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Sample records for az nuclei application

  1. 77 FR 20356 - Foreign-Trade Zone 277-Western Maricopa County, AZ; Application for Manufacturing Authority...

    Science.gov (United States)

    2012-04-04

    ... Manufacturing Authority; Suntech Arizona, Inc., (Solar Panel Manufacturing), Goodyear, AZ An application has..., Inc., grantee of FTZ 277, requesting manufacturing authority on behalf of Suntech Arizona, Inc... foreign inputs that become scrap or waste during manufacturing. FTZ designation would further...

  2. The hot blow forming of AZ31 Mg sheet: Formability assessment and application development

    Science.gov (United States)

    Carter, Jon T.; Krajewski, Paul E.; Verma, Ravi

    2008-11-01

    The hot blow forming of magnesium sheet offers significant opportunity for forming complex, lightweight parts for automotive applications. This paper characterizes the elevated-temperature formability of AZ31 magnesium sheet materials and the effect of processing conditions on the performance of these materials. In addition, magnesium sheet application development at General Motors Corporation is reviewed.

  3. Brueckner-AMD method and its applications to light nuclei

    International Nuclear Information System (INIS)

    We propose a new approach employing the Brueckner-AMD in which the G-matrix is calculated using the antisymmetrized molecular dynamics (AMD). Its applications to some light nuclei are demonstrated, and the high reliability of the description of the shell and cluster structures is discussed. (author)

  4. nuclei

    Directory of Open Access Journals (Sweden)

    Minkov N.

    2016-01-01

    Full Text Available We study the effects of quadrupole-octupole deformations on the energy and magnetic properties of high-K isomeric states in even-even heavy and superheavy nuclei. The neutron two-quasiparticle (2qp isomeric energies and magnetic dipole moments are calculated within a deformed shell model with the Bardeen-Cooper- Schrieffer (BCS pairing interaction over a wide range of quadrupole and octupole deformations. We found that in most cases the magnetic moments exhibit a pronounced sensitivity to the octupole deformation, while the 2qp energies indicate regions of nuclei in which the presence of high-K isomeric states may be associated with the presence of octupole softness or even with octupole deformation. In the present work we also examine the influence of the BCS pairing strength on the energy of the blocked isomer configuration. We show that the formation of 2qp energy minima in the space of quadrupole-octupole and eventually higher multipolarity deformations is a subtle effect depending on nuclear pairing correlations.

  5. Electrochemical polymerization of pyrrole over AZ31 Mg alloy for biomedical applications

    International Nuclear Information System (INIS)

    Highlights: ► Polymerization of pyrrole over AZ31 Mg was carried out using cyclic voltammetry. ► Pyrrole concentration was optimized to accomplish the adherent and uniform coating. ► Effect of monomer concentration on the surface morphology was discussed. ► Corrosion resistance of AZ31 Mg in SBF was studied as a function of Py concentration. ► PPy coated AZ31 Mg alloy exhibited enhanced corrosion resistance at 0.25 M of Py. -- Abstract: Electrochemical polymerization of pyrrole (Py) from aqueous salicylate solution over AZ31 Mg alloy was carried out using cyclic voltammetry (CV). The effect of monomer concentration on the surface and electrochemical corrosion in simulated body fluid (SBF) were analysed. Attenuated total reflection-infrared (ATR-IR) spectra showed the characteristic ring stretching peaks for polypyrrole (PPy). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies exhibited typical cauliflower morphology with rough surface for PPy coated AZ31 Mg alloy. Open circuit potential measurement and potentiodynamic polarization studies revealed that the coating prepared using 0.25 M of Py had positive shift of about 120 mV in corrosion potential and lower corrosion current density (0.03 mA/cm2) compared to other concentrations and uncoated AZ31 Mg alloy (0.25 mA/cm2). Electrochemical impedance spectroscopic (EIS) studies of uncoated and PPy coated Mg alloy in SBF revealed three-time constants behaviour with about one order of increment in impedance value for 0.25 M of Py

  6. High energy beams of radioactive nuclei and their biomedical applications

    International Nuclear Information System (INIS)

    The availability of high-energy beams of radioactive species is the most recent advancement in the field of accelerator physics. One of the primary interactions experienced by relativistic heavy ions is the peripheral nuclear collision. Thus, radioactive nuclei are produced as secondary particles from peripheral nuclear fragmentation reactions. These nuclei have trajectories and energies differing little from that of the parent particle. Various radioactive beams produced as a result of these reactions, now available on a regular basis from the Bevalac, are: 11C, 13N, 15O, and 19Ne with sufficient intensity. Besides the interest in such beams for nuclear physics, important applications in therapeutic and diagnostic radiology and in nuclear medicine are discussed

  7. Surface characterization and cytocompatibility evaluation of silanized magnesium alloy AZ91 for biomedical applications

    Directory of Open Access Journals (Sweden)

    Agnieszka Witecka, Akiko Yamamoto, Henryk Dybiec and Wojciech Swieszkowski

    2012-01-01

    Full Text Available Mg alloys with high Al contents have superior corrosion resistance in aqueous environments, but poor cytocompatibility compared to that of pure Mg. We have silanized the cast AZ91 alloy to improve its cytocompatibility using five different silanes: ethyltriethoxysilane (S1, 3-aminopropyltriethoxysilane (S2, 3-isocyanatopyltriethoxysilane (S3, phenyltriethoxysilane (S4 and octadecyltriethoxysilane (S5. The surface hydrophilicity/hydrophobicity was evaluated by water contact angle measurements. X-ray photoelectron analysis was performed to investigate the changes in surface states and chemical composition. All silane reagents increased adsorption of the albumin to the modified surface. In vitro cytocompatibility evaluation revealed that silanization improved cell growth on AZ91 modified by silane S1. Measurement of the concentration of Mg2+ ions released during the cell culture indicated that silanization does not affect substrate degradation.

  8. Characterization and degradation behavior of AZ31 alloy surface modified by bone-like hydroxyapatite for implant applications

    Science.gov (United States)

    Wen, Cuilian; Guan, Shaokang; Peng, Li; Ren, Chenxing; Wang, Xiang; Hu, Zhonghua

    2009-04-01

    Hydroxyapatite (HA) coating on AZ31 alloy substrate was prepared by a cathodic electrodeposition method. The as-deposited specimen was then post-treated with hot alkali solution to improve the corrosion resistance and bioactivity for implant applications. The microstructure and composition of HA coating, as well as its degradation behavior in simulated body fluid (SBF) were investigated. It reveals that the as-deposited coating consists of dicalcium phosphate dehydrate (DCPD, CaHPO 4·2H 2O) and HA. While 10 μm-thick nanowhisker HA coatings doped with Na +, Mg +, HPO 42-and CO 32- can be found after NaOH alkali treatment, which exhibits a very similar composition of natural bone. The post-treated coating was composed of needle-like particles with 1000 nm in length and 35 nm in diameter, having a slenderness ratio of about 28.6. Electrochemical tests shows that the Ecorr of Mg substrate significantly increased from -1.6 to -1.42 V after surface modified by HA coatings. There was obvious mass gain on post-treated specimen immersed in SBF during the first 30 days due to the Ca-P-Mg deposition. The HA-coated AZ31 alloy could slow down the degradation rate and effectively induce the deposition of Ca-P-Mg apatite in SBF, showing a good bioactivity.

  9. Newton method for the optimization of a new constitutive equation for the plastic flow dependent on the strain. Application to magnesium alloys AZ80 and AZ61

    International Nuclear Information System (INIS)

    A new numerical algorithm has been developed, based on Newton's method, for optimizing the parameters of a new strain dependent constitutive equation, based on the Garofalo equation. The adjustment is direct, with second order algorithms, for an equation derived from that of Garofalo with a nonlinear objective function. This new optimization algorithm has been applied to creep data of two magnesium alloys AZ80 and AZ61, having an unusual plastic behavior. A certain pseudo-stationary exists in the curves studied, in the sense that the usual deformation states are not manifested in an obvious way. The parameters of the new constitutive equation, dependent on strain, have been determined for these alloys. For analyzing the precision of the parameters and the accuracy of modeling of the stress-strain curves, a statistical treatment has been applied which allows assessing the quality of the constitutive equation proposed and the consistency of these parameters. Stress-strain curves have been compared with the modeling results, reaching a good agreement between the experimental data and the resulting modeling. (Author)

  10. Application of Anand's constitutive model on twin roll casting process of AZ31 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    HU Xiao-dong; JU Dong-ying

    2006-01-01

    Twin-roll thin strip casting process combines casting and hot rolling into a single process,in which thermal stress and thermal mechanical stress were involved. Considering the high temperature gradient,the existing of liquid and solid regions and rolling deformation,suitable constitutive model is the key to describe the process. Anand's model is a temperature-dependent,rate-dependent and unified of creep and plasticity model and the Jaumann derivative was employed in Anand's model which makes the constitutive model frame-indifferent or objective,therefore the highly nonlinearities behavior in the twin-roll casting process can be simulated. The parameters of the Anand's model were regressed based on the compression tests of AZ31 magnesium alloy. The simulation results reveal that the Anand's model can well describe the deformation characteristics of twin-roll casting process. Based on the simulation results,the form of evolution equations in Anand's model was discussed.

  11. Spectral distribution in nuclei: general principles and applications

    International Nuclear Information System (INIS)

    The subject of spectral distribution methods where one derives and applies the locally smoothed forms of observables in nuclei is briefly reviewed. It is well understood that the local forms (with respect to energy) of the level density function, expectation values and strength densities are Gaussian, linear (or ratio of Gaussians) and a bivariate Gaussian respectively. To accomodate symmetries in the above forms, one has to deal with multivariate distributions in general; for example the angular-momentum (J) decomposition leads to a bivariate Gaussian form for the level density. These results extend to indefinitely large spaces by method of partitioning and they generate convolution forms. The origin of these remarkable spectral properties is discussed and shell model examples are given to substantiate their applicability to nuclear systems. Spectral distribution theory is a practical, usable theory because the smoothed forms are defined in terms of traces of low particle-rank operators, and the trace information propagates. Finally the application of the spectral methods for a wide range of nuclear problems is discussed; these include binding energies, orbit occupancies , electromagnetic and β-decay sum rule quantities, analysis of operators, symmetry breaking, numerical level densities, and determination of bounds on time-reversal non-invariant part of nucleon-nucleon interaction. (author). 11 figs., 159 refs

  12. In Vitro Analysis of Electrophoretic Deposited Fluoridated Hydroxyapatite Coating on Micro-arc Oxidized AZ91 Magnesium Alloy for Biomaterials Applications

    Science.gov (United States)

    Razavi, Mehdi; Fathi, Mohammadhossein; Savabi, Omid; Vashaee, Daryoosh; Tayebi, Lobat

    2015-03-01

    Magnesium (Mg) alloys have been recently introduced as a biodegradable implant for orthopedic applications. However, their fast corrosion, low bioactivity, and mechanical integrity have limited their clinical applications. The main aim of this research was to improve such properties of the AZ91 Mg alloy through surface modifications. For this purpose, nanostructured fluoridated hydroxyapatite (FHA) was coated on AZ91 Mg alloy by micro-arc oxidation and electrophoretic deposition method. The coated alloy was characterized through scanning electron microscopy, transmission electron microscopy, X-ray diffraction, in vitro corrosion tests, mechanical tests, and cytocompatibility evaluation. The results confirmed the improvement of the corrosion resistance, in vitro bioactivity, mechanical integrity, and the cytocompatibility of the coated Mg alloy. Therefore, the nanostructured FHA coating can offer a promising way to improve the properties of the Mg alloy for orthopedic applications.

  13. The collective model of nuclei and its applications

    International Nuclear Information System (INIS)

    The concepts of collective coordinates, the establishment of Hamiltonian collectives through the model of the drop of liquid or through the symmetry arguments and of the operators in these variables are discussed in this study. The passage of the laboratory system to the principal axis system is discussed thoroughly with the symmetries produced by this transformation, considering a drop in two dimensions. It is also observed that the deformed nuclei have some properties that can be described through the rotation-vibration and symmetric rotor models. The rotation-vibration model concerns the nuclei with axially symmetric deformations in the basic state and its importance is due to the fact that it can predict the nuclear spectrum at low energies. The asymmetric rotor model assumes the existence of triaxial nuclei and considers their collective movements. This model can be modified taking into consideration that vibrations β can also appear. Finally there is a comparison between the two models and the models are also compared with the experiment. (author)

  14. Dynamical symmetries of BEC: exact energy formulas and an application to alpha-conjugate nuclei

    International Nuclear Information System (INIS)

    An algebraic approach, based on dynamical symmetries, to Bose-Einstein condensates will be illustrated. It allows to write symmetry-dictated exact energy formulas for boson condensates that depend typically on a few quantum numbers. The application to alpha condensation in nuclei will be discussed in detail, showing that symmetry alone is sufficient to predict the energy of N-alpha states in alpha conjugate nuclei. Experiments that might improve the present knowledge will be suggested. (author)

  15. Thermodynamical properties of microscopic IBM and applications to Fe nuclei

    International Nuclear Information System (INIS)

    By using the microscopic sdIBM-2 formalism, procedures of canonical ensemble average and saddle point method, the finite-temperature internal energy, specific heat and level density of nucleus were calculated. The temperature of the phase transition of thermal excitation mode was determined in reference to the single boson energy. As there is a peak in the specific heat, it is established that the symmetric phase transition takes place in the nucleus. For 56,58Fe isotopes, numerical results were calculated and compared with the experimental data and the values obtained by quantum Monte Carlo calculations. The present results indicate that this approach can be successfully used in describing light nuclei and their finite-temperature behavior

  16. Newton method for the optimization of a new constitutive equation for the plastic flow dependent on the strain. Application to magnesium alloys AZ80 and AZ61; El metodo de Newton para la optimizacion de una nueva ecuacion constitutiva para la fluencia plastica dependiente de la deformacion. Aplicacin a las aleaciones de magnesio AZ80 y AZ61

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, V.; Roeorp, R.; Carsi, M.; Ruano, O. A.

    2013-07-01

    A new numerical algorithm has been developed, based on Newton's method, for optimizing the parameters of a new strain dependent constitutive equation, based on the Garofalo equation. The adjustment is direct, with second order algorithms, for an equation derived from that of Garofalo with a nonlinear objective function. This new optimization algorithm has been applied to creep data of two magnesium alloys AZ80 and AZ61, having an unusual plastic behavior. A certain pseudo-stationary exists in the curves studied, in the sense that the usual deformation states are not manifested in an obvious way. The parameters of the new constitutive equation, dependent on strain, have been determined for these alloys. For analyzing the precision of the parameters and the accuracy of modeling of the stress-strain curves, a statistical treatment has been applied which allows assessing the quality of the constitutive equation proposed and the consistency of these parameters. Stress-strain curves have been compared with the modeling results, reaching a good agreement between the experimental data and the resulting modeling. (Author)

  17. Physical conditions in photodissociation regions: Application to galactic nuclei

    Science.gov (United States)

    Wolfire, M. G.; Tielens, A. G. G. M.; Hollenbach, David J.

    1990-01-01

    Infrared and sub-millimeter observations are used in a simple procedure to determine average physical properties of the neutral interstellar medium in Galactic photodissociation regions as well as in ensembles of clouds which exist in the nuclei of luminous infrared galaxies. The relevant observations include the Infrared Astronomy Satellite (IRAS) infrared continuum measurements, infrared spectroscopy of the fine-structure lines of SiII 35 microns, OI 63 microns, and CII 158 microns, and the 2.6 mm CO (J=1-0) rotational transition. The diagnostic capabilities of the OI 145 microns line is also addressed. Researchers attribute these emission lines as well as the continuum to the atomic/molecular photodissociation region on the surfaces of molecular clouds which are illuminated by strong ultraviolet fields. They use the theoretical photodissociation region models of Tielens and Hollenbach (1985, Ap. J., 291, 722) to construct simple diagrams which utilize line ratios and line to continuum ratios to determine the average gas density n, the average incident far-ultraviolet flux G sub o, and the temperature of the atomic gas T.

  18. Physical conditions in photodissociation regions - Application to galactic nuclei

    Science.gov (United States)

    Wolfire, Mark G.; Tielens, A. G. G. M.; Hollenbach, David

    1990-01-01

    A procedure is outlined which determines the physical characteristics of the neutral interstellar medium in the nuclei of luminous galaxies. The method uses millimeter and IR observations to find the mass and density of the molecular and atomic gas components as well as the UV flux incident on clouds. The area and volume filling factors and approximate number of clouds and cloud radii are also found. For the Galactic center, about 100 clouds of radius about 0.4 pc and density about 100,000/cu cm are found within about 5 pc. The atomic gas temperature is about 700 K and the FUV field on clouds is about 100,000 times the local Galactic FUV field. The flux is consistent with a central source of luminosity of 2-3 x 10 to the 7th solar. Roughly 100,000 clouds of radius roughly 0.4 pc are found within the roughly 330 pc nuclear region of M82. The large number of clouds produces a projected area filling factor approaching unity. Cloud heating may be dominated by an intense interstellar UV flux.

  19. 6th International Workshop on Application of Lasers in Atomic Nuclei Research

    CERN Document Server

    Błaszczak, Z; Marinova, K; LASER 2004

    2006-01-01

    6th International Workshop on Application of Lasers in Atomic Nuclei Research, LASER 2004, held in Poznan, Poland, 24-27 May, 2004 Researchers and graduate students interested in the Mössbauer Effect and its applications will find this volume indispensable. The volume presents the most recent developments in the methodology of Mössbauer spectroscopy. Reprinted from Hyperfine Interactions (HYPE) Volume 162, 1-4

  20. Many-body quantum chaos: Recent developments and applications to nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, J.M.G. [Grupo de Fisica Nuclear, Departamento de Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Kar, K. [Theory Division, Saha Institute of Nuclear Physics, Calcutta 700 064 (India); Kota, V.K.B. [Physical Research Laboratory, Ahmedabad 380 009 (India); Molina, R.A. [Instituto de Estructura de la Materia, CSIC, Serrano 123, E-28006 Madrid (Spain); Relano, A. [Grupo de Fisica Nuclear, Departamento de Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Instituto de Estructura de la Materia, CSIC, Serrano 123, E-28006 Madrid (Spain); Retamosa, J., E-mail: iokin@nuc3.fis.ucm.e [Grupo de Fisica Nuclear, Departamento de Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid, E-28040 Madrid (Spain)

    2011-03-15

    In the last decade, there has been an increasing interest in the analysis of energy level spectra and wave functions of nuclei, particles, atoms and other quantum many-body systems by means of statistical methods and random matrix ensembles. The concept of quantum chaos plays a central role for understanding the universal properties of the energy spectrum of quantum systems. Since these properties concern the whole spectrum, statistical methods become an essential tool. Besides random matrix theory, new theoretical developments making use of information theory, time series analysis, and the merging of thermodynamics and the semiclassical approximation are emphasized. Applications of these methods to quantum systems, especially to atomic nuclei, are reviewed. We focus on recent developments like the study of 'imperfect spectra' to estimate the degree of symmetry breaking or the fraction of missing levels, the existence of chaos remnants in nuclear masses, the onset of chaos in nuclei, and advances in the comprehension of the Hamiltonian structure in many-body systems. Finally, some applications of statistical spectroscopy methods generated by many-body chaos and two-body random matrix ensembles are described, with emphasis on Gamow-Teller strength sums and beta decay rates for stellar evolution and supernovae.

  1. Calculating the transfer function of noise removal by principal component analysis and application to AzTEC observations

    CERN Document Server

    Downes, Thomas Patrick; Scott, Kimberly; Austermann, Jason; Wilson, Grant W

    2011-01-01

    Instruments using arrays of many bolometers have become increasingly common in the past decade. The maps produced by such instruments typically include the filtering effects of the instrument as well as those from subsequent steps performed in the reduction of the data. Therefore interpretation of the maps is dependent upon accurately calculating the transfer function of the chosen reduction technique on the signal of interest. Many of these instruments use non-linear and iterative techniques to reduce their data because such methods can offer improved signal-to-noise over those that are purely linear, particularly for signals at scales comparable to that subtended by the array. We discuss a general approach for measuring the transfer function of principal component analysis (PCA) on point sources that are small compared to the spatial extent seen by any single bolometer within the array. The results are applied to previously released AzTEC catalogues of the COSMOS, Lockman Hole, Subaru XMM-Newton Deep Field,...

  2. Application of X-ray microtomography to analysis of cavitation in AZ61 magnesium alloy during hot deformation

    International Nuclear Information System (INIS)

    Research highlights: → The novel use of X-ray microtomography to study cavitation in magnesium alloys. → Proof that large particles dominate cavity nucleation in this alloy. → Proof that progressively smaller particles nucleate cavities during deformation. - Abstract: The efficiency of particles in acting as cavity formation sites during hot deformation was investigated for a fine-grained wrought magnesium-aluminium-zinc (AZ series) alloy using X-ray micro tomography. Two methodologies were developed to determine the particle/cavity association from 3-dimensional data, each clearly demonstrating that particles act as a major formation site for cavitation. The particles forming cavities were identified and characterised. It is shown that progressively smaller particles nucleate cavities as strain increases. This is due to concurrent grain growth which reduces the critical particle diameter for cavity nucleation during testing, leading to a continuous cavity nucleation. Particle agglomerates are shown to be particularly potent sites for cavity formation, leading to large and complex shaped cavities even if the individual particles within the agglomerate are below the critical particle diameter for cavity nucleation.

  3. 78 FR 57923 - Arizona Disaster #AZ-00029

    Science.gov (United States)

    2013-09-20

    ... ADMINISTRATION Arizona Disaster AZ-00029 AGENCY: Small Business Administration. ACTION: Notice. SUMMARY: This is...: 06/13/2014. ADDRESSES: Submit completed loan applications to: U.S. Small Business Administration... CONTACT: A. Escobar, Office of Disaster Assistance, U.S. Small Business Administration, 409 3rd Street...

  4. Long-term corrosion inhibition mechanism of microarc oxidation coated AZ31 Mg alloys for biomedical applications

    International Nuclear Information System (INIS)

    Highlights: ► The corrosion behavior is significantly affected by the long-term immersion. ► The degradation is inhibited due to the corrosion product layer. ► The corrosion resistance is enhanced by optimized MAO electrolyte concentrations. ► The corrosion inhibition mechanism is presented by a Flash animation. - Abstract: This paper addresses the long-term corrosion behavior of microarc oxidation coated Mg alloys immersed in simulated body fluid for 28 days. The coatings on AZ31 Mg alloys were produced in the electrolyte of sodium phosphate (Na3PO4) at the concentration of 20 g/L, 30 g/L and 40 g/L, respectively. Scanning electron microscope (SEM) and optical micrograph were used to observe the microstructure of the samples before and after corrosion. The composition of the MAO coating and corrosion products were determined by X-Ray Diffraction (XRD). Corrosion product identification showed that hydroxyapatite (HA) was formed on the surface of the corroded samples. The ratio of Ca/P in HA determined by the X-ray Fluorescence (XRF) technique showed that HA is an acceptable biocompatible implant material. The potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were employed to characterize the corrosion rate and the electrochemical impedance. The corrosion resistance of the coated Mg alloys can be enhanced by optimizing the electrolyte concentrations for fabricating samples, and is enhanced after immersing the coated samples in simulated body fluid for more than 14 days. The enhanced corrosion resistance after long-term immersion is attributed to a corrosion product layer formed on the sample surface. The inhibition mechanism of the corrosion process is discussed and presented with an animation

  5. New Microscopic Derivation of the Interacting Boson Model and its Applications to Exotic Nuclei

    International Nuclear Information System (INIS)

    We propose a new approach to microscopic derivation of the Interacting Boson Model (IBM) Hamiltonian for general cases, starting from the mean-field model, e.g., the one with Skyrme-type interactions [1]. The multi-fermion dynamics of the surface deformations and the effects of the nuclear force are simulated in terms of bosons. By comparing Potential Energy Surface (PES) of the mean-field model with that of the IBM, the parameters of the IBM Hamiltonian can be obtained as functions of N and Z. Using this method, levels and wave functions of the excited states are computed precisely: Various situations of three dynamical symmetries and quantum shape/phase transitions, including the recently proposed critical-point symmetries [2,3], can be reproduced quite nicely. Moreover, intriguing spectroscopic properties, e.g., unexpectedly large region of the E(5) symmetry, are predicted for experimentally unknown exotic nuclei such as W-Os isotopes with A ≥200. As another application, we will present the results of the systematic calculations for Z ≤50 nuclei such as Ru isotopes. These results contain the predicted energy levels for unexplored territory. Finally, we would like to discuss the uniqueness of the derived IBM parameters with the aid of the wavelet analysis, taking Sm and Ba isotopes as examples.(author)

  6. Tank 241-AZ-101 tank characterization plan

    International Nuclear Information System (INIS)

    The Defense Nuclear Facilities Safety Board has advised the DOE to concentrate the near-term sampling and analysis activities on identification and resolution of safety issues. The Data Quality Objective (DQO) process was chosen as a tool to be used in the resolution of safety issues. As a result, A revision in the Federal Facilities Agreement and Consent Order (Tri-Party Agreement) milestone M-44 has been made, which states that ''A Tank Characterization Plan (TCP) will also be developed for each double-shell tank (DST) and single-shell tank (SST) using the DQO process. Development of TCPs by the DQO process is intended to allow users to ensure their needs will be met and that resources are devoted to gaining only necessary information''. This document satisfies that requirement for Tank 241-AZ-101 (AZ-101) sampling activities. Tank AZ-101 is currently a non-Watch List tank, so the only DQOs applicable to this tank are the safety screening DQO and the compatibility DQO, as described below. The contents of Tank AZ-101, as of October 31, 1994, consisted of 3,630 kL (960 kgal) of dilute non-complexed waste and aging waste from PUREX (NCAW, neutralized current acid waste). Tank AZ-101 is expected to have two primary layers. The bottom layer is composed of 132 kL of sludge, and the top layer is composed of 3,500 kL of supernatant, with a total tank waste depth of approximately 8.87 meters

  7. Tank 241-AZ-102 tank characterization plan

    International Nuclear Information System (INIS)

    The Defense Nuclear Facilities Safety Board has advised the DOE to concentrate the near-term sampling and analysis activities on identification and resolution of safety issues. The Data Quality Objective (DQO) process was chosen as a tool to be used in the resolution of safety issues. As a result, a revision in the Federal Facilities Agreement and Consent Order (Tri-Party Agreement) milestone M-44 has been made, which states that ''A Tank Characterization Plan (TCP) will also be developed for each double-shell tank (DST) and single-shell tank (SST) using the DQO process ... Development of TCPs by the DQO process is intended to allow users to ensure their needs will be met and that resources are devoted to gaining only necessary information''. This document satisfies that requirement for tank 241-AZ-102 (AZ-102) sampling activities. Tank AZ-102 is currently a non-Watch List tank, so the only DQOs applicable to this tank are the safety screening DQO and the compatibility DQO, as described below. The current contents of Tank AZ-102, as of October 31, 1994, consisted of 3,600 kL (950 kgal) of dilute non-complexed waste and aging waste from PUREX (NCAW, neutralized current acid waste). Tank AZ-102 is expected to have two primary layers. The bottom layer is composed of 360 kL of sludge, and the top layer is composed of 3,240 kL of supernatant, with a total tank waste depth of approximately 8.9 meters

  8. Cloud Condensation Nuclei Prediction Error from Application of Kohler Theory: Importance for the Aerosol Indirect Effect

    Science.gov (United States)

    Sotiropoulou, Rafaella-Eleni P.; Nenes, Athanasios; Adams, Peter J.; Seinfeld, John H.

    2007-01-01

    In situ observations of aerosol and cloud condensation nuclei (CCN) and the GISS GCM Model II' with an online aerosol simulation and explicit aerosol-cloud interactions are used to quantify the uncertainty in radiative forcing and autoconversion rate from application of Kohler theory. Simulations suggest that application of Koehler theory introduces a 10-20% uncertainty in global average indirect forcing and 2-11% uncertainty in autoconversion. Regionally, the uncertainty in indirect forcing ranges between 10-20%, and 5-50% for autoconversion. These results are insensitive to the range of updraft velocity and water vapor uptake coefficient considered. This study suggests that Koehler theory (as implemented in climate models) is not a significant source of uncertainty for aerosol indirect forcing but can be substantial for assessments of aerosol effects on the hydrological cycle in climatically sensitive regions of the globe. This implies that improvements in the representation of GCM subgrid processes and aerosol size distribution will mostly benefit indirect forcing assessments. Predictions of autoconversion, by nature, will be subject to considerable uncertainty; its reduction may require explicit representation of size-resolved aerosol composition and mixing state.

  9. Deuteron-induced nucleon transfer reactions within an ab initio framework: First application to p-shell nuclei

    CERN Document Server

    Raimondi, Francesco; Navrátil, Petr; Quaglioni, Sofia

    2016-01-01

    Background: Low-energy transfer reactions in which a proton is stripped from a deuteron projectile and dropped into a target play a crucial role in the formation of nuclei in both primordial and stellar nucleosynthesis, as well as in the study of exotic nuclei using radioactive beam facilities and inverse kinematics. Ab initio approaches have been successfully applied to describe the $^3$H$(d,n)^4$He and $^3$He$(d,p)^4$He fusion processes. Purpose: An ab initio treatment of transfer reactions would also be desirable for heavier targets. In this work, we extend the ab initio description of $(d,p)$ reactions to processes with light $p$-shell nuclei. As a first application, we study the elastic scattering of deuterium on $^7$Li and the ${}^{7}$Li($d$,$p$)${}^{8}$Li transfer reaction based on a two-body Hamiltonian. Methods: We use the no-core shell model to compute the wave functions of the nuclei involved in the reaction, and describe the dynamics between targets and projectiles with the help of microscopic-clu...

  10. 7th International Workshop on Application of Lasers in Atomic Nuclei Research “Nuclear Ground and Isometric State Properties”

    CERN Document Server

    Błaszczak, Z; Marinova, K; LASER 2006

    2007-01-01

    7th International Workshop on Application of Lasers in Atomic Nuclei Research, LASER 2004, held in Poznan, Poland, May 29-June 01, 2006 Researchers and PhD students interested in recent results in the nuclear structure investigation by laser spectroscopy, the progress of the experimental technique and the future developments in the field will find this volume indispensable. Reprinted from Hyperfine Interactions (HYPE) Volume ???

  11. Correlation between the surface chemistry and the atmospheric corrosion of AZ31, AZ80 and AZ91D magnesium alloys

    OpenAIRE

    Feliu Jr., S.; Pardo, Angel; Merino, M. C.; Coy, A. E.; Viejo, F.; Arrabal, R.

    2009-01-01

    X-ray photoelectron spectroscopy (XPS) was used in order to investigate the correlation between the surface chemistry and the atmospheric corrosion of AZ31, AZ80 and AZ91D magnesium alloys exposed to 98% relative humidity at 50 °C. Commercially pure magnesium, used as the reference material, revealed MgO, Mg(OH)2 and tracers of magnesium carbonate in the air-formed film. For the AZ80 and AZ91D alloys, the amount of magnesium carbonate formed on the surface reached similar values to those of M...

  12. Multi-dimensional constraint relativistic mean field model and applications in actinide and transfermium nuclei

    CERN Document Server

    Lu, Bing-Nan; Zhao, En-Guang; Zhou, Shan-Gui

    2013-01-01

    In this contribution we present some results of potential energy surfaces of actinide and transfermium nuclei from multi-dimensional constrained relativistic mean field (MDC-RMF) models. Recently we developed multi-dimensional constrained covariant density functional theories (MDC-CDFT) in which all shape degrees of freedom $\\beta_{\\lambda\\mu}$ with even $\\mu$ are allowed and the functional can be one of the following four forms: the meson exchange or point-coupling nucleon interactions combined with the non-linear or density-dependent couplings. In MDC-RMF models, the pairing correlations are treated with the BCS method. With MDC-RMF models, the potential energy surfaces of even-even actinide nuclei were investigated and the effect of triaxiality on the fission barriers in these nuclei was discussed. The non-axial reflection-asymmetric $\\beta_{32}$ shape in some transfermium nuclei with $N=150$, namely $^{246}$Cm, $^{248}$Cf, $^{250}$Fm, and $^{252}$No were also studied.

  13. Fluorescent Magnesium Nanocomplex in Protein Scaffold for Cell Nuclei Imaging Application

    Energy Technology Data Exchange (ETDEWEB)

    Pandya, Alok [Ahmedabad Univ. (India); Tripathi, Apritam [Ahmedabad Univ. (India); Purohit, Rahul [Ahmedabad Univ. (India); Singh, Sanjay [Ahmedabad Univ. (India); Nandasiri, Manjula I. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Karakoti, Ajay S. [Ahmedabad Univ. (India); Singh, Surinder P. [National Physical Lab., New Delhi (India); Shanker, Rishi [Ahmedabad Univ. (India)

    2015-10-27

    Here in, we report a facile strategy for the synthesis of water-soluble ultra-fine blue emitting fluorescent Magnesium nanoparticles-protein complex (MgNC). This MgNC is demonstrated to exhibit excellent photo stability and biocompatibility. It was also observed that MgNC stain cell nuclei with high specifcity.

  14. Pseudomagic nuclei

    International Nuclear Information System (INIS)

    It has been shown previously that, below a critical angular momentum, yrast bands of non-magic nuclei are well described by the two-parameter variable moment of inertia model. Some striking exceptions to this rule are found in nuclei which have the same mass number as doubly magic nuclei but possess either one (or two) proton pairs beyond a magic number and one (or two) neutron hole pairs, or vice versa. Yrast bands in these 'pseudomagic' nuclei resemble those in magic nuclei. (author)

  15. Deuteron-induced nucleon transfer reactions within an ab initio framework: First application to p -shell nuclei

    Science.gov (United States)

    Raimondi, Francesco; Hupin, Guillaume; Navrátil, Petr; Quaglioni, Sofia

    2016-05-01

    Background: Low-energy transfer reactions in which a proton is stripped from a deuteron projectile and dropped into a target play a crucial role in the formation of nuclei in both primordial and stellar nucleosynthesis, as well as in the study of exotic nuclei using radioactive beam facilities and inverse kinematics. Ab initio approaches have been successfully applied to describe the 3H (d ,n )4He and 3He(d ,p )4He fusion processes. Purpose: An ab initio treatment of transfer reactions would also be desirable for heavier targets. In this work, we extend the ab initio description of (d ,p ) reactions to processes with light p -shell nuclei. As a first application, we study the elastic scattering of deuterium on 7Li and the 7Li(d ,p )8Li transfer reaction based on a two-body Hamiltonian. Methods: We use the no-core shell model to compute the wave functions of the nuclei involved in the reaction, and describe the dynamics between targets and projectiles with the help of microscopic-cluster states in the spirit of the resonating group method. Results: The shapes of the excitation functions for deuterons impinging on 7Li are qualitatively reproduced up to the deuteron breakup energy. The interplay between d -7Li and p -8Li particle-decay channels determines some features of the 9Be spectrum above the d +7Li threshold. Our prediction for the parity of the 17.298 MeV resonance is at odds with the experimental assignment. Conclusions: Deuteron stripping reactions with p -shell targets can now be computed ab initio, but calculations are very demanding. A quantitative description of the 7Li(d ,p )8Li reaction will require further work to include the effect of three-nucleon forces and additional decay channels and to improve the convergence rate of our calculations.

  16. Model for asymptotic D-state parameters of light nuclei: application to 4 He

    International Nuclear Information System (INIS)

    A simple method for calculating the asymptotic D state observables for light nuclei is suggested. The method exploits the dominant clusters of the light nuclei. The method is applied to calculate the 4 He asymptotic D to S normalization ratio ρα and the closely related D state parameter Dα2. The study predicts a correlation between Dα2 and Bα, and between ρα and Bα, where Bα is the binding energy of 4 He. The present study yields ρα ∼ -0.14 and Dα2 ∼ -0.12 fm2 consistent with the correct experimental ηD and the binding energies of the deuteron, triton, and the α particle where ηd is the deuteron D state to S state to S state normalization ratio. (author)

  17. Binding energy of finite nuclei in Jastrow-Factor-Cluster method with applications in helium

    International Nuclear Information System (INIS)

    A general expression for the binding energy of finite nuclei in the Jastrow-Factor-Cluster method is developed upto the three-body cluster term with centre of mass correction. It is applied in mass A = 3 and 4 with the standard Chakkalakal function and the average Pauli condition. Compared to the previous work of Afnan (1969) better saturation properties are obtained for two- and three-body truncation. Convergence is also better. (orig.)

  18. BASEMAP, PINAL COUNTY, AZ

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Basemap datasets comprise six of the seven FGDC themes of geospatial data that are used by most GIS applications (Note: the seventh framework theme, orthographic...

  19. Applicability of the orientation average formula in heavy-ion fusion reactions of deformed nuclei

    CERN Document Server

    Rumin, T; Takigawa, N; Rumin, Tamanna; Hagino, Kouichi; Takigawa, Noboru

    2001-01-01

    In heavy-ion fusion reactions involving a well deformed nucleus, one often assumes that the orientation of the target nucleus does not change during the reaction. We discuss the accuracy of this procedure by analyzing the excitation function of the fusion cross section and the fusion barrier distribution in the reactions of $^{154}$Sm target with various projectiles ranging from $^{12}$C to $^{40}$Ar. It is shown that the approximation gradually looses its accuracy with increasing charge product of the projectile and target nuclei because of the effects of finite excitation energy of the target nucleus. The relevance of such inaccuracy in analyzing the experimental data is also discussed.

  20. High-spin states in boson models with applications to actinide nuclei

    CERN Document Server

    Kuyucak, S

    1995-01-01

    We use the 1/N expansion formalism in a systematic study of high-spin states in the sd and sdg boson models with emphasis on spin dependence of moment of inertia and E2 transitions. The results are applied to the high-spin states in the actinide nuclei ^{232}Th, ^{234-238}U, where the need for g bosons is especially acute but until now, no realistic calculation existed. We find that the d-boson energy plays a crucial role in description of the high-spin data.

  1. Dynamical approach to bidimensional tunneling. Application to the proton emission from deformed nuclei

    International Nuclear Information System (INIS)

    The quasi-stationary state decrease by tunneling quantum effect through an anisotropic potential barrier, has been studied by solving numerically the time dependent Schroedinger equation. Applied to excited states proton decay from deformed nuclei, this approach showed the competition during the tunneling between the properties of the initial quasi-stationary wave function and the deformed potential barrier. The importance of the residual angular momentum and its time dependent variation, have also been studied. Particular cases of the states decrease to a quasi-stationary particle have been studied function of the nuclear deformation around the crossing point. Results show that the nuclear states knowledge is now possible. (A.L.B.)

  2. Application of the Time of Flight Technique for Lifetime Measurements with Relativistic Beams of Heavy Nuclei

    CERN Document Server

    Chester, A; Bazin, D; Becerril, A; Campbell, C M; Cook, J M; Dewald, A; Dinca, D C; Miller, D; Moeller, V; Müller, W F; Norris, R P; Portillo, M; Starosta, K; Stolz, A; Terry, J R; Vaman, C; Zwahlen, H

    2006-01-01

    A novel method for picosecond lifetime measurements of excited gamma-ray emitting nuclear states has been developed for fast beams from fragmentation reactions. A test measurement was carried out with a beam of 124Xe at an energy of ~55 MeV/u. The beam ions were Coulomb excited to the first 2+ state on a movable target. Excited nuclei emerged from the target and decayed in flight after a distance related to the lifetime. A stationary degrader positioned downstream with respect to the target was used to further reduce the velocity of the excited nuclei. As a consequence, the gamma-ray decays from the 2+ excited state that occurred before or after traversing the degrader were measured at a different Doppler shift. The gamma-ray spectra were analyzed from the forward ring of the Segmented Germanium Array; this ring positioned at 37 deg. simultaneously provides the largest sensitivity to changes in velocity and the best energy resolution. The ratio of intensities in the peaks at different Doppler shifts gives inf...

  3. Adubação do algodoeiro: III - Ensaios sôbre a aplicação de azôto em cobertura Fertilizer experiments with cotton: III - Nitrogen application as top-dressing

    Directory of Open Access Journals (Sweden)

    O. S. Neves

    1957-01-01

    Full Text Available Nêste trabalho são apresentados os resultados de três ensaios realizados entre 1937-38 e 1941-42 nas Estações Experimentais de Mococa (em solo massapê, Tietê (em solo argiloso e Tatuí (em terra-roxa-misturada, nos quais canteiros adubados com fósforo e potássio foram comparados com outros que receberam esses nutrientes e mais azoto. O azôto, nas formas de salitre do Chile e de Calnitro IG (mistura de nitrato de amônio e carbonato de cálcio, foi aplicado pelo método usual - nos sulcos destinados às sementes, no momento do plantio - ou em cobertura, ao achar-se o algodoeiro em pleno desenvolvimento. O fósforo e o potássio foram sempre empregados nos sulcos de plantio. Em Mococa e Tietê os ensaios foram conduzidos, nos mesmos canteiros, por três anos; em Tatuí, por dois. Os dois adubos azotados deram o mesmo resultado. Em Mococa eles aumentaram apreciavelmente a produção, não se notando diferença entre os dois métodos de aplicação, mas em Tietê e Tatuí o azôto empregado nos sulcos de plantio em regra pouco aumentou ou mesmo deprimiu a produção, ao passo que a elevou consideravelmente quando aplicado em cobertura. • Em Mococa, tendo chovido nos dias imediatos ao plantio, os adubos azotados não prejudicaram o "stand"; por outro lado, as chuvas caídas não foram suficientes para lixiviar o azôto do massapê utilizado para o ensaio. Em Tietê o motivo principal da inferioridade da aplicação dos adubos azotados nos sulcos de plantio foi o prejuízo que eles causaram às sementes em germinação, devido à elevada concentração local de sais. Num dos dois anos de ensaio em Tatuí ficou patente que o azôto empregado nos sulcos foi arrastado antes de o algodoeiro o ter podido absorver, enquanto o aplicado em cobertura não sofreu esse inconveniente. O arrastamento do azôto, que se dá sobretudo quando êle é empregado por ocasião do plantio, não teve grande influência nos presentes ensaios, porque os solos

  4. A microscopic derivation of nuclear collective rotation-vibration model and its application to nuclei

    Science.gov (United States)

    Gulshani, P.

    2016-07-01

    We derive a microscopic version of the successful phenomenological hydrodynamic model of Bohr-Davydov-Faessler-Greiner for collective rotation-vibration motion of an axially symmetric deformed nucleus. The derivation is not limited to small oscillation amplitude. The nuclear Schrodinger equation is canonically transformed to collective co-ordinates, which is then linearized using a constrained variational method. The associated constraints are imposed on the wavefunction rather than on the particle co-ordinates. The approach yields three self-consistent, time-reversal invariant, cranking-type Schrodinger equations for the rotation-vibration and intrinsic motions, and a self-consistency equation. For harmonic oscillator mean-field potentials, these equations are solved in closed forms for excitation energy, cut-off angular momentum, and other nuclear properties for the ground-state rotational band in some deformed nuclei. The results are compared with measured data.

  5. Exotic nuclei

    International Nuclear Information System (INIS)

    The nuclei far from the β-stability valley which are referred to as exotic nuclei have attracted considerable interest in recent years. Undoubtedly the study of the exotic nuclei is destined to be one of the frontier fields in nuclear structure physics. The recent experiments with radioactive beams have opened up this new era in nuclear spectroscopy. The lighter exotic nuclei are observed to show quite interesting features. For example, a halo structure has been attributed to 11Li in order to explain the observed large matter radius. Also, it is seen that 31--33Na show deformed characteristics rather than the spherical shape expected from the shell closure at N = 20. This points towards a need for a new investigation of the shell structure as one moves away from the β - stability valley. With the aforementioned interesting features observed for the lighter nuclei, clearly one question of great interest is whether similar effects can be seen in heavy nuclei. New calculations using the relativistic mean field approach have been performed for a range of nuclei over a wide range of isotopes up to those with a large excess of neutrons. In the present talk, some interesting new results obtained from these calculations win be discussed

  6. Quantum algebra Uqp(u2) and application to the rotational collective dynamics of the nuclei

    International Nuclear Information System (INIS)

    This thesis concerns some aspects of new symmetries in Nuclear Physics. It comprises three parts. The first one is devoted to the study of the quantum algebra Uqp(u2). More precisely, we develop its Hopf algebraic structure and we study its co-product structure. The bases of the representation theory of Uqp(u2) are introduced. On one hand, we construct the finite-dimensional irreducible representations of Uqp(u2). On the other hand, we calculate the Clebsch-Gordan coefficients with the projection operator method. To complete our study, we construct some deformed boson mappings of the quantum algebras Uqp(u2), Uq2(su2) and Uqp(u1,1). The second part deals with the construction of a new phenomenological model of the non rigid rotator. This model is based on the quantum algebra Uqp(u2). The rotational energy and the E2 reduced transition probabilities are obtained. They depend on the two deformation parameters q and p of the quantum algebra. We show how the use of the two-parameter deformation of the algebra Uqp(u2) leads to a generalization of the Uq(su2)-rotator model. We also introduce a new model of the anharmonic oscillator on the basis of the quantum algebra Uqp(u2). We show that the system of the Uq(su2)-rotator and of the anharmonic oscillator can be coupled with the use of the deformation parameters of Uqp(u2). A ro-vibration energy formula and expansion 'a la' Dunham are obtained. The aim of the lest part is to apply our non rigid rotator model to the rotational collective dynamics of the superdeformed nuclei of the A∼130 - 150 and A∼190 mass regions and deformed nuclei of the actinide and rare earth series. We adjust the free parameters of our model and compare our results with those arising from four other models of the non rigid rotator. A comparative analysis is given in terms of transition energies. We calculate the dynamical moments of inertia with the fitted parameters. A comparison between the results of different models shows the role played by

  7. The AzTEC Mathematics Project (AMP).

    Science.gov (United States)

    Johnson, Gae R.

    The AzTEC Mathematics Project (AMP) is a statewide partnership among Arizona's Regents universities and state community colleges, partner school districts, and economic communities. AzTec is committed to preparing highly qualified K-12 mathematics and science teachers. AMP targeted Native American teachers and teachers of Native American students…

  8. Meteor Crater, AZ

    Science.gov (United States)

    2002-01-01

    -term research and technology program designed to examine Earth's land, oceans, atmosphere, ice and life as a total integrated system.The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.Size: 15 x 30 km (9 x 18 miles) Location: 35.1 deg. North lat., 111.0 deg. West long. Orientation: Northeast at top Image Data: ASTER bands 1,2, and 3. Original Data Resolution: 15 m Date Acquired: May 17, 2001

  9. Correlation between the surface chemistry and the atmospheric corrosion of AZ31, AZ80 and AZ91D magnesium alloys

    International Nuclear Information System (INIS)

    X-ray photoelectron spectroscopy (XPS) was used in order to investigate the correlation between the surface chemistry and the atmospheric corrosion of AZ31, AZ80 and AZ91D magnesium alloys exposed to 98% relative humidity at 50 deg. C. Commercially pure magnesium, used as the reference material, revealed MgO, Mg(OH)2 and tracers of magnesium carbonate in the air-formed film. For the AZ80 and AZ91D alloys, the amount of magnesium carbonate formed on the surface reached similar values to those of MgO and Mg(OH)2. A linear relation between the amount of magnesium carbonate formed on the surface and the subsequent corrosion behaviour in the humid environment was found. The AZ80 alloy revealed the highest amount of magnesium carbonate in the air-formed film and the highest atmospheric corrosion resistance, even higher than the AZ91D alloy, indicating that aluminium distribution in the alloy microstructure influenced the amount of magnesium carbonate formed.

  10. Correlation between the surface chemistry and the atmospheric corrosion of AZ31, AZ80 and AZ91D magnesium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Feliu, S. [Centro Nacional de Investigaciones Metalurgicas CSIC, Avda. Gregorio del Amo 8, 28040 Madrid (Spain); Pardo, A. [Departamento de Ciencia de Materiales, Facultad de Quimica, Universidad Complutense, 28040 Madrid (Spain)], E-mail: anpardo@quim.ucm.es; Merino, M.C. [Departamento de Ciencia de Materiales, Facultad de Quimica, Universidad Complutense, 28040 Madrid (Spain); Coy, A.E.; Viejo, F.; Arrabal, R. [Corrosion and Protection Centre, School of Materials, University of Manchester, P.O. Box 88, Sackville Street, Manchester M60 1QD (United Kingdom)

    2009-01-15

    X-ray photoelectron spectroscopy (XPS) was used in order to investigate the correlation between the surface chemistry and the atmospheric corrosion of AZ31, AZ80 and AZ91D magnesium alloys exposed to 98% relative humidity at 50 deg. C. Commercially pure magnesium, used as the reference material, revealed MgO, Mg(OH){sub 2} and tracers of magnesium carbonate in the air-formed film. For the AZ80 and AZ91D alloys, the amount of magnesium carbonate formed on the surface reached similar values to those of MgO and Mg(OH){sub 2}. A linear relation between the amount of magnesium carbonate formed on the surface and the subsequent corrosion behaviour in the humid environment was found. The AZ80 alloy revealed the highest amount of magnesium carbonate in the air-formed film and the highest atmospheric corrosion resistance, even higher than the AZ91D alloy, indicating that aluminium distribution in the alloy microstructure influenced the amount of magnesium carbonate formed.

  11. Correlation between the surface chemistry and the atmospheric corrosion of AZ31, AZ80 and AZ91D magnesium alloys

    Science.gov (United States)

    Feliu, S., Jr.; Pardo, A.; Merino, M. C.; Coy, A. E.; Viejo, F.; Arrabal, R.

    2009-01-01

    X-ray photoelectron spectroscopy (XPS) was used in order to investigate the correlation between the surface chemistry and the atmospheric corrosion of AZ31, AZ80 and AZ91D magnesium alloys exposed to 98% relative humidity at 50 °C. Commercially pure magnesium, used as the reference material, revealed MgO, Mg(OH) 2 and tracers of magnesium carbonate in the air-formed film. For the AZ80 and AZ91D alloys, the amount of magnesium carbonate formed on the surface reached similar values to those of MgO and Mg(OH) 2. A linear relation between the amount of magnesium carbonate formed on the surface and the subsequent corrosion behaviour in the humid environment was found. The AZ80 alloy revealed the highest amount of magnesium carbonate in the air-formed film and the highest atmospheric corrosion resistance, even higher than the AZ91D alloy, indicating that aluminium distribution in the alloy microstructure influenced the amount of magnesium carbonate formed.

  12. Corrosion resistance of AZ31 alloy after plastic working in NaCl solutions

    Directory of Open Access Journals (Sweden)

    W. Walke

    2011-04-01

    Full Text Available Purpose: The purpose of the study was to assess corrosion resistance of magnesium alloy AZ31 (Mg-Al-Zn alloy after plastic working in NaCl solutions. It presents currently applied methods of magnesium alloys plastic working. Basic groups of magnesium alloys that are used for plastic working have been discussed.Design/methodology/approach: Corrosion tests of AZ31 alloy were carried out in solution with concentration of 0.01-2 M NaCl with application of the system for electrochemical tests VoltaLab®PGP201. Resistance to electrochemical corrosion was evaluated on the ground of registered anodic polarisation curves by means of potentiodynamic method. Immersion tests were carried out in NaCl solutions in the time of 1-5 days. Scanning microscopy enabled to present microstructure of AZ31 after immersion tests.Findings: Results of all carried out tests explicitly prove deterioration of corrosion properties of magnesium alloy AZ31 with the increase in molar concentration of NaCl solution.Practical implications: It was determined that irrespective of molar concentration of NaCl solution pitting corrosion was found in the tested alloy. It proves that application of protective coating on elements made of the tested alloy is necessary.Originality/value: Literature gives the results of corrosion tests with reference to cast alloy AZ31. Tests of corrosion resistance of hot rolled AZ31 in chloride solutions have been made for the first time.

  13. Four-body correlations in heavy nuclei

    International Nuclear Information System (INIS)

    The origin of four-body correlations in heavy nuclei is studied. It is found that the physical picture for this phenomenon can be different in heavy and light nuclei. An application to the /sup 208/Pb region is made

  14. System Description for Tank 241-AZ-101 Waste Retrieval Data Acquisition System

    Energy Technology Data Exchange (ETDEWEB)

    ROMERO, S.G.

    2000-02-14

    The proposed activity provides the description of the Data Acquisition System for Tank 241-AZ-101. This description is documented in HNF-5572, Tank 241-AZ-101 Waste Retrieval Data Acquisition System (DAS). This activity supports the planned mixer pump tests for Tank 241-AZ-101. Tank 241-AZ-101 has been selected for the first full-scale demonstration of a mixer pump system. The tank currently holds over 960,000 gallons of neutralized current acid waste, including approximately 12.7 inches of settling solids (sludge) at the bottom of the tank. As described in Addendum 4 of the FSAR (LMHC 2000a), two 300 HP mixer pumps with associated measurement and monitoring equipment have been installed in Tank 241-AZ-101. The purpose of the Tank 241-AZ-101 retrieval system Data Acquisition System (DAS) is to provide monitoring and data acquisition of key parameters in order to confirm the effectiveness of the mixer pumps utilized for suspending solids in the tank. The suspension of solids in Tank 241-AZ-101 is necessary for pretreatment of the neutralized current acid waste and eventual disposal as glass via the Hanford Waste Vitrification Plant. HNF-5572 provides a basic description of the Tank 241-AZ-101 retrieval system DAS, including the field instrumentation and application software. The DAS is provided to fulfill requirements for data collection and monitoring. This document is not an operations procedure or is it intended to describe the mixing operation. This USQ screening provides evaluation of HNF-5572 (Revision 1) including the changes as documented on ECN 654001. The changes include (1) add information on historical trending and data backup, (2) modify DAS I/O list in Appendix E to reflect actual conditions in the field, and (3) delete IP address in Appendix F per Lockheed Martin Services, Inc. request.

  15. Lysobacter capsici AZ78 can be combined with copper to effectively control Plasmopara viticola on grapevine.

    Science.gov (United States)

    Puopolo, Gerardo; Giovannini, Oscar; Pertot, Ilaria

    2014-01-01

    The bacterial genus Lysobacter represents a still underdeveloped source of biocontrol agents able to protect plants against pathogenic oomycetes. In this work the L. capsici strain AZ78 was evaluated with regard to the biological control of Plasmopara viticola, the causal agent of grapevine downy mildew. L. capsici AZ78 is able to resist copper ions and its resistance to this metal is probably due to the presence of genes coding for copper oxidase (copA) and copper exporting PIB-type ATPases (ctpA). The presence of both genes was also detected in other members of the Lysobacter genus. Resistance to copper allowed L. capsici AZ78 to be combined with a low-dose of a copper-based fungicide, leading to more effective control of grapevine downy mildew. Notably, prophylactic application of L. capsici AZ78 alone to grapevine leaves reduced downy mildew disease to the same degree as a copper-based fungicide. Furthermore, L. capsici AZ78 persists in the phyllosphere of grapevine plants and tolerates environmental stresses such as starvation, freezing, mild heat shock and UV light irradiation. These traits suggest that L. capsici AZ78 could be a suitable candidate for developing a new biofungicide to be used in combination with copper to control grapevine downy mildew. PMID:24140153

  16. Kaonic nuclei

    Czech Academy of Sciences Publication Activity Database

    Mareš, Jiří; Friedman, E.; Gal, A.

    -, č. 56 (2006), s. 95-98. ISSN 0323-0465 R&D Projects: GA AV ČR IAA1048305 Institutional research plan: CEZ:AV0Z10480505 Keywords : key words * kaonic nuclei * Kbar-nucleus interactions Subject RIV: BE - Theoretical Physics Impact factor: 0.647, year: 2006

  17. Superdeformed nuclei

    International Nuclear Information System (INIS)

    Superdeformation was first proposed some twenty years ago to explain the fission isomers observed in some actinide nuclei. It was later realized that superdeformed shapes can occur at high angular momentum in lighter nuclei. The interest in the mechanisms responsible for these exotic shapes has increased enormously with the discovery of a superdeformed band of nineteen discrete lines in 152Dy (8). At about the same time, evidence for highly deformed nuclei (axis ratio 3:2) was also reported near 132Ce(9). Striking properties emerged from the first experiments, such as the essentially constant energy spacing between transitions (picket-fence spectra), the unexpectedly strong population of superdeformed bands at high spins, and the apparent lack of a link between the superdeformed states and the yrast levels. These findings were reviewed by Nolan and Twin. The present article follows upon their work and discusses the wealth of information that has since become available. This includes the discovery of a new island of superdeformation near A = 190, the detailed spectroscopy of ground and excited bands in the superdeformed well near A = 150 and A = 190, the surprising occurrence of superdeformed bands with identical transition energies in nuclei differing by one or two mass units, and the improved understanding of mechanisms responsible for the feeding into and the decay out of the superdeformed states

  18. The A-Z of electronuclear power

    International Nuclear Information System (INIS)

    Both a bilingual translation aid and a reference book, 'The A-Z of Electronuclear Power' covers the full range of electronuclear activities and the English and French terminology relating to the different phases of the modern industrial process

  19. Spectroscopic Classification of ASASSN-16az

    Science.gov (United States)

    Prieto, J. L.; Rich, J.; Shappee, B. J.

    2016-02-01

    We obtained an optical spectrum (range 360-920 nm) of ASASSN-16az (ATel #8614) on UT 2016 Feb 2.4 with WFCCD mounted on the du Pont 2.5m telescope at Las Campanas Observatory. Cross-correlation with a library of SN spectra using SNID (Blondin & Tonry 2007, ApJ, 666, 1024) shows that ASASSN-16az is a normal Type Ia at +10 days.

  20. Applications of the O(18) limit of the IBM-3 to the Z ∼ N ∼ 40 nuclei

    International Nuclear Information System (INIS)

    Low-energy levels of the N ∼ Z ∼ 40 nuclei are characterized by the following complex but interesting features: (1) large deformation δ2 ∼ 0.4, (2) Ex(41+)/Ex(21+) ∼ 2.5 and (3) Ex(02+) ∼ Ex(41+) ∼ Ex(22+). In terms of the O(18) limit of IBM-3, investigated the level structure of the N ∼ Z ∼ 40 nuclei have been investigated. (author)

  1. Magic nuclei

    International Nuclear Information System (INIS)

    4 nuclei of Nickel-48 have been produced in the GANIL accelerator. This nucleus is made up of 28 protons and 20 neutrons, it has at least 10 neutrons less than natural nickel but it is doubly magic: both protons and neutrons are distributed on full shells. It appears as if being doubly magic could compensate for the instability due to the shortage of neutrons. (A.C.)

  2. light charged particles induced nuclear reaction on some medium weight nuclei for particles applications

    International Nuclear Information System (INIS)

    The radioisotopes of indium, cadmium and tin have many practical and medical applications. Their standard routes for production are proton or deuteron induced reactions on natural or enriched cadmium or tin. The production via 3He induced reactions on natural or enriched cadmium was rarely discussed. In this study 3He induced reactions on natural cadmium were measured utilizing the stacked-foil technique. The primary incident beam energy was 27 MeV extracted from the MGC- 20E cyclotron, Debrecen, Hungary.the exciatation functions for the reactions natCd(3He,x) 115g,111mCd, 117m,g,116m,115m,114m,113m,111g,110m,g,109g,108g,107gIn and 117m,113,111,110Sn were evaluated. The data were compared with the available literature data.Different theoretical nuclear reaction models were also used to predict the cross sections for those reactions. The used models were ALICE-IPPE, TALYS-1.2 and EMPIRE-03. The experimental data were compared also to the theoretical model calculations. The theoretical models did not describe most of the experimental results.The isomeric cross section ratios for the isomeric pairs117m,gIn and 110m,gIn were calculated. The isomeric cross section ratio depends on the spins of the states of the interested isomeric pair. The calculated isomeric ratios helped to identify the mechanisms of the reactions involved.The integral yields for some medically relevant isotopes were calculated using the excitation function curves

  3. On validity of application of Student's t-criterion for experimental proof of Wigner's SU(4)-symmetry reestablishing in atomic nuclei

    International Nuclear Information System (INIS)

    The article provide verification of normal distribution of factor R using agreement criteria W of Shapiro-Wilk and basing on experimental values of Franzini-Radicati factor R. The obtained results demonstrating that the factor R of Franzini-Radicati in the range of isospin 1/2z<28 has normal distribution. That justify application of t-criterion of Student for the experimental proof of restoration of Wigner's SU(4)-symmetry in atomic nuclei. (author)

  4. Tank 241-AZ-101 Mixer Pump Test Vapor Sampling and Analysis Plan

    International Nuclear Information System (INIS)

    This sampling and analysis plan (SAP) identifies characterization objectives pertaining to sample collection, laboratory analytical evaluation, and reporting requirements for vapor samples obtained during the operation of mixer pumps in tank 241-AZ-101. The primary purpose of the mixer pump test (MPT) is to demonstrate that the two 300 horsepower mixer pumps installed in tank 241-AZ-101 can mobilize the settled sludge so that it can be retrieved for treatment and vitrification Sampling will be performed in accordance with Tank 241-AZ-101 Mixer Pump Test Data Quality Objective (Banning 1999) and Data Quality Objectives for Regulatory Requirements for Hazardous and Radioactive Air Emissions Sampling and Analysis (Mulkey 1999). The sampling will verify if current air emission estimates used in the permit application are correct and provide information for future air permit applications

  5. Az újraelosztásról

    OpenAIRE

    Bródy, András

    1998-01-01

    Magyarországon az adók összege meghaladja a teljes béralapot. Indokolttá vált felmérni, hogy milyen szerepet töltenek be az adók az árak alakulásában. A magyar adórendszer a vizsgálat szerint eltorzítja a bér/ár arányt és tartós munkanélküliséget okoz. Nem az egyenlőtlenséget tompítja, nem az elesetteket segíti, hanem a gazdagok felhalmozási eszközévé vált. Nem szektorsemleges. Megváltoztatja a gazdaság alapvető arányait és félrevezet minden gazdasági elemzést....

  6. Rapid coating of AZ31 magnesium alloy with calcium deficient hydroxyapatite using microwave energy

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Yufu, E-mail: Yufu.Ren@rockets.utoledo.edu [Department of Mechanical, Industrial and Manufacturing Engineering, The University of Toledo, Toledo, OH (United States); Zhou, Huan [Department of Mechanical, Industrial and Manufacturing Engineering, The University of Toledo, Toledo, OH (United States); Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, Jiangsu (China); Nabiyouni, Maryam [Department of Bioengineering, The University of Toledo, Toledo, OH (United States); Bhaduri, Sarit B. [Department of Mechanical, Industrial and Manufacturing Engineering, The University of Toledo, Toledo, OH (United States); Division of Dentistry, The University of Toledo, Toledo, OH (United States)

    2015-04-01

    Due to their unique biodegradability, magnesium alloys have been recognized as suitable metallic implant materials for degradable bone implants and bioresorbable cardiovascular stents. However, the extremely high degradation rate of magnesium alloys in physiological environment has restricted its practical application. This paper reports the use of a novel microwave assisted coating technology to improve the in vitro corrosion resistance and biocompatibility of Mg alloy AZ31. Results indicate that a dense calcium deficient hydroxyapatite (CDHA) layer was uniformly coated on a AZ31 substrate in less than 10 min. Weight loss measurement and SEM were used to evaluate corrosion behaviors in vitro of coated samples and of non-coated samples. It was seen that CDHA coatings remarkably reduced the mass loss of AZ31 alloy after 7 days of immersion in SBF. In addition, the prompt precipitation of bone-like apatite layer on the sample surface during immersion demonstrated a good bioactivity of the CDHA coatings. Proliferation of osteoblast cells was promoted in 5 days of incubation, which indicated that the CDHA coatings could improve the cytocompatibility of the AZ31 alloy. All the results suggest that the CDHA coatings, serving as a protective layer, can enhance the corrosion resistance and biological response of magnesium alloys. Furthermore, this microwave assisted coating technology could be a promising method for rapid surface modification of biomedical materials. - Highlights: • A microwave assisted coating process for biodegradable Mg alloy. • CDHA coatings were successfully developed on AZ31 alloy in minutes. • The as-deposited CDHA coatings significantly reduced the degradation rate of AZ31 alloy. • The CDHA coated AZ31 alloy showed good bioactivity and biocompatibility in vitro. • The microwave assisted coating process can be used as rapid surface modification for bioimplants.

  7. Rapid coating of AZ31 magnesium alloy with calcium deficient hydroxyapatite using microwave energy

    International Nuclear Information System (INIS)

    Due to their unique biodegradability, magnesium alloys have been recognized as suitable metallic implant materials for degradable bone implants and bioresorbable cardiovascular stents. However, the extremely high degradation rate of magnesium alloys in physiological environment has restricted its practical application. This paper reports the use of a novel microwave assisted coating technology to improve the in vitro corrosion resistance and biocompatibility of Mg alloy AZ31. Results indicate that a dense calcium deficient hydroxyapatite (CDHA) layer was uniformly coated on a AZ31 substrate in less than 10 min. Weight loss measurement and SEM were used to evaluate corrosion behaviors in vitro of coated samples and of non-coated samples. It was seen that CDHA coatings remarkably reduced the mass loss of AZ31 alloy after 7 days of immersion in SBF. In addition, the prompt precipitation of bone-like apatite layer on the sample surface during immersion demonstrated a good bioactivity of the CDHA coatings. Proliferation of osteoblast cells was promoted in 5 days of incubation, which indicated that the CDHA coatings could improve the cytocompatibility of the AZ31 alloy. All the results suggest that the CDHA coatings, serving as a protective layer, can enhance the corrosion resistance and biological response of magnesium alloys. Furthermore, this microwave assisted coating technology could be a promising method for rapid surface modification of biomedical materials. - Highlights: • A microwave assisted coating process for biodegradable Mg alloy. • CDHA coatings were successfully developed on AZ31 alloy in minutes. • The as-deposited CDHA coatings significantly reduced the degradation rate of AZ31 alloy. • The CDHA coated AZ31 alloy showed good bioactivity and biocompatibility in vitro. • The microwave assisted coating process can be used as rapid surface modification for bioimplants

  8. In vitro Study on Biodegradable AZ31 Magnesium Alloy Fibers Reinforced PLGA Composite

    Institute of Scientific and Technical Information of China (English)

    Y.H.Wu; N.Li; Y.Cheng; Y.F.Zheng; Y.Han

    2013-01-01

    AZ31 magnesium alloy fibers reinforced poly(lactic-co-glycolic acid) (PLGA) composites were prepared and their mechanical property,immersion corrosion behavior and biocompatibility were studied.The tensile test showed that with the addition of AZ31 fibers,the composites had a significant increment in tensile strength and elongation.For the direct cell attachment test,all the cells showed a healthy morphology and spread well on the experimental sample surfaces.The immersion results indicated that pH values of the immersion medium increased with increasing AZ31 fiber contents.All the in vitro experimental results indicated that this new kind of magnesium alloy fibers reinforced PLGA composites show a potential for future biomedical applications.

  9. Comparison of corrosion behaviors of AZ31, AZ91,AM60 and ZK60 magnesium alloys

    Institute of Scientific and Technical Information of China (English)

    CHENG Ying-liang; QIN Ting-wei; WANG Hui-min; ZHANG Zhao

    2009-01-01

    The corrosion behaviours of four kinds of rolled magnesium alloys of AZ31, AZ91, AM60 and ZK60 were studied in 1 mol/L sodium chloride solution. The results of EIS and potentiodynamic polarization show that the corrosion resistance of the four materials is ranked as ZK60>AM60>AZ31>AZ91. The corrosion processes of the four magnesium alloys were also analyzed by SEM and energy dispersive spectroscopy(EDS). The results show that the corrosion patterns of the four alloys are localized corrosion and the galvanic couples formed by the second phase particles and the matrix are the main source of the localized corrosion of magnesium alloys. The corrosion resistance of the different magnesium alloys has direct relationship with the concentration of alloying elements and microstructure of magnesium alloys. The ratio of the β phase in AZ91 is higher than that in AZ31 and the β phase can form micro-galvanic cell with the alloy matrix, as a result, the corrosion resistance of AZ31 will be higher than AZ91. The manganese element in AM60 magnesium alloy can form the second phase particle of AlMnFe, which can reduce the Fe content in magnesium alloy matrix, purifying the microstructure of alloy, as a result, the corrosion resistance of AM60 is improved. However, due to the more noble galvanic couples of AlMnFe and matrix, the microscopic corrosion morphology of AM60 is more localized. The zirconium element in ZK60 magnesium alloy can refine grain, form stable compounds with Fe and Si, and purify the composition of alloy, which results in the good corrosion resistance of ZK60 magnesium alloy.

  10. Atmospheric corrosion of magnesium alloys AZ31 and AZ61 under continuous condensation conditions

    OpenAIRE

    Feliu Jr., S.; Maffiotte, C.; Galván Sierra, Juan Carlos; Barranco, Violeta

    2011-01-01

    This paper studies the corrosion rate of magnesium alloys AZ31 and AZ61 exposed in humid air under continuous condensation conditions. The shape of the gravimetric curves for corrosion progress suggests that the process is controlled by factors related with the corrosion product layer growing on the metallic surface according to gravimetric results there is an initial period in which only a small part of the corroded metal is incorporated in the corrosion product layer, but after longer testi...

  11. 76 FR 619 - Arizona Disaster #AZ-00014

    Science.gov (United States)

    2011-01-05

    ... ADMINISTRATION Arizona Disaster AZ-00014 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for the... Disaster Assistance, U.S. Small Business Administration, 409 3rd Street, SW., Suite 6050, Washington,...

  12. Application of the triaxial quadrupole-octupole rotor to the ground and negative-parity levels of actinide nuclei

    Science.gov (United States)

    Nadirbekov, M. S.; Minkov, N.; Strecker, M.; Scheid, W.

    2016-03-01

    In this work, we examine the possibility to describe yrast positive- and negative-parity excitations of deformed even-even nuclei through a collective rotation model in which the nuclear surface is characterized by triaxial quadrupole and octupole deformations. The nuclear moments of inertia are expressed as sums of quadrupole and octupole parts. By assuming an adiabatic separation of rotation and vibration degrees of freedom, we suppose that the structure of the positive- and negative-parity bands may be determined by the triaxial-rigid-rotor motion of the nucleus. By diagonalizing the Hamiltonian in a symmetrized rotor basis with embedded parity, we obtain a model description for the yrast positive- and negative-parity bands in several actinide nuclei. We show that the energy displacement between the opposite-parity sequences can be explained as the result of the quadrupole-octupole triaxiality.

  13. Application of the triaxial quadrupole-octupole rotor to the ground and negative-parity levels of actinide nuclei

    CERN Document Server

    Nadirbekov, M S; Strecker, M; Scheid, W

    2016-01-01

    In this work we examine the possibility to describe yrast positive- and negative-parity excitations of deformed even-even nuclei through a collective rotation model in which the nuclear surface is characterized by triaxial quadrupole and octupole deformations. The nuclear moments of inertia are expressed as sums of quadrupole and octupole parts. By assuming an adiabatic separation of rotation and vibration degrees of freedom we suppose that the structure of the positive- and negative- parity bands may be determined by the triaxial-rigid-rotor motion of the nucleus. By diagonalizing the Hamiltonian in a symmetrized rotor basis with embedded parity we obtain a model description for the yrast positive- and negative-parity bands in several actinide nuclei. We show that the energy displacement between the opposite-parity sequences can be explained as the result of the quadrupole-octupole triaxiality.

  14. Applications of mean-field plus nearest-orbit pairing interaction model to well-deformed nuclei

    CERN Document Server

    Chen Yu Yan

    2002-01-01

    An exactly solvable mean-field plus nearest-orbit pairing model for describing the well-deformed nuclei is adopted for study of the nuclei in rare-earth and actinide regions. Binding energies and pairing excitation energies of sup 1 sup 5 sup 8 sup - sup 1 sup 7 sup 1 Er, sup 1 sup 6 sup 0 sup - sup 1 sup 7 sup 8 Yb, sup 1 sup 7 sup 0 sup - sup 1 sup 8 sup 3 Hf, sup 2 sup 2 sup 6 sup - sup 2 sup 3 sup 4 Th, sup 2 sup 3 sup 0 sup - sup 2 sup 4 sup 0 U and sup 2 sup 3 sup 6 sup - sup 2 sup 4 sup 3 Pu isotopes are calculated and compared with the corresponding experimental results

  15. Description of collective and quasiparticle excitations in deformed actinide nuclei: The first application of the Heavy Shell Model

    CERN Document Server

    Cui, Ji-Wei; Chen, Fang-Qi; Sun, Yang; Wu, Cheng-Li; Gao, Zao-Chun

    2014-01-01

    The Heavy Shell Model (HSM) (Y. Sun and C.-L. Wu, Phys. Rev. C 68, 024315 (2003)) was proposed to take the advantages of two existing models, the projected shell model (PSM) and the Fermion Dynamical Symmetry Model (FDSM). To construct HSM, one extends the PSM by adding collective D-pairs into the intrinsic basis. The HSM is expected to describe simultaneously low-lying collective and quasi-particle excitations in deformed nuclei, and still keeps the model space tractable even for the heaviest systems. As the first numerical realization of the HSM, we study systematically the band structures for some deformed actinide nuclei, with a model space including up to 4-quasiparticle and 1-D-pair configurations. The calculated energy levels for the ground- state bands, the collective bands such as {\\beta} - and {\\gamma} -bands, and some quasiparticle bands agree well with known experimental data. Some low-lying quasiparticle bands are predicted, awaiting experimental confirmation.

  16. Measurements of the fragmentation cross sections of relativistic heavy nuclei and their application to cosmic-ray propagation

    International Nuclear Information System (INIS)

    The fragmentation cross sections of relativistic krypton, xenon, holmium and gold nuclei in targets of aluminium, carbon and polyethylene were measured. The beams were accelerated to maximum rigidity at the LBL Bevalac, corresponding to energies per nucleon of 1.5, 1.2, 1.1, and 1.0 Gev/amu for Kr, Xe, Ho, and Au respectively. The total and partial charge changing cross sections were determined for each beam and target combination, and cross sections in hydrogen were derived from the polyethylene (CH2) and carbon data. The total cross sections were found to be 10% to 15% smaller than the predictions of a formula derived from measurements made with lower charge nuclei, and a new representation of the dependence of the total charge changing cross sections on beam and target charge was determined

  17. Effects of Sm on the grain refinement, microstructures and mechanical properties of AZ31 magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Ming [National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); School of Mechanical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Hu, Xiaoyu [National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Peng, Liming, E-mail: plm616@sjtu.edu.cn [National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Fu, Penghuai [National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Peng, Yinghong [School of Mechanical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China)

    2015-01-03

    The effects of samarium (Sm) on the grain refinement, microstructures and mechanical properties of as-cast AZ31 (Mg–3Al–1Zn–0.3Mn) magnesium (Mg) alloy have been investigated. Very serious grain coarsening happens when Sm content is between 0.16% and 1.18%. This is due to both the reactions between Al and Sm which reduce the constitutional undercooling effect and the lack of Al{sub 2}Sm heterogeneous nuclei. However, excellent grain refinement effect is achieved at Sm content above 2.17%, which is because the in-situ formed Al{sub 2}Sm particles significantly promote heterogeneous nucleation. The main phases in AZ31–xSm alloys include α-Mg, β-Mg{sub 17}Al{sub 12}, Al{sub 11}Sm{sub 3} and Al{sub 2}Sm. The Mg{sub 17}Al{sub 12} phase is gradually suppressed by the increase in Sm content, and the Al{sub 2}Sm is present at a higher Sm content. Because of grain refinement strengthening and secondary phase strengthening effects, the room temperature tensile property of AZ31–3.13Sm alloy has the optimal value of YS78.7MPa–UTS216.7MPa-EL13.6%.

  18. Fully self-consistent multiparticle-multi-hole configuration mixing method - Applications to a few light nuclei

    International Nuclear Information System (INIS)

    This thesis project takes part in the development of the multiparticle-multi-hole configuration mixing method aiming to describe the structure of atomic nuclei. Based on a double variational principle, this approach allows to determine the expansion coefficients of the wave function and the single-particle states at the same time. In this work we apply for the first time the fully self-consistent formalism of the mp-mh method to the description of a few p- and sd-shell nuclei, using the D1S Gogny interaction. A first study of the 12C nucleus is performed in order to test the doubly iterative convergence procedure when different types of truncation criteria are applied to select the many-body configurations included in the wave-function. A detailed analysis of the effect caused by the orbital optimization is conducted. In particular, its impact on the one-body density and on the fragmentation of the ground state wave function is analyzed. A systematic study of sd-shell nuclei is then performed. A careful analysis of the correlation content of the ground state is first conducted and observables quantities such as binding and separation energies, as well as charge radii are calculated and compared to experimental data. Satisfactory results are found. Spectroscopic properties are also studied. Excitation energies of low-lying states are found in very good agreement with experiment, and the study of magnetic dipole features are also satisfactory. Calculation of electric quadrupole properties, and in particular transition probabilities B(E2), however reveal a clear lack of collectivity of the wave function, due to the reduced valence space used to select the many-body configurations. Although the renormalization of orbitals leads to an important fragmentation of the ground state wave function, only little effect is observed on B(E2) probabilities. A tentative explanation is given. Finally, the structure description of nuclei provided by the multiparticle

  19. A comparative corrosion behavior of Mg, AZ31 and AZ91 alloys in 3.5% NaCl solution

    OpenAIRE

    I.B. Singh; M Singh; Das, S.

    2015-01-01

    The corrosion behavior of Mg, AZ31 and AZ91 has been evaluated in 3.5% NaCl solution using weight loss, electrochemical polarization and impedance measurements. Corrosion rate derived from the weight losses demonstrated the occurrence of steeply fast corrosion reaction on AZ91 alloy after three hours of immersion, indicating the start of galvanic corrosion. An increase of corrosion rate with immersion time was also observed for AZ31 but with lesser extent than AZ91 alloy. Whereas Mg metals sh...

  20. SUZAKU VIEW OF THE SWIFT/BAT ACTIVE GALACTIC NUCLEI. III. APPLICATION OF NUMERICAL TORUS MODELS TO TWO NEARLY COMPTON THICK ACTIVE GALACTIC NUCLEI (NGC 612 AND NGC 3081)

    International Nuclear Information System (INIS)

    The broadband spectra of two Swift/BAT active galactic nuclei (AGNs) obtained from Suzaku follow-up observations are studied: NGC 612 and NGC 3081. Fitting with standard models, we find that both sources show similar spectra characterized by heavy absorption with NH ≅ 1024 cm-2, and the fraction of scattered light is fscat = 0.5%-0.8%, and the solid angle of the reflection component is Ω/2π = 0.4-1.1. To investigate the geometry of the torus, we apply numerical spectral models utilizing Monte Carlo simulations by Ikeda et al. to the Suzaku spectra. We find that our data are well explained by this torus model, which has four geometrical parameters. The fit results suggest that NGC 612 has a torus half-opening angle of ≅60 deg. - 70 deg. and is observed from a nearly edge-on angle with a small amount of scattering gas, while NGC 3081 has a very small opening angle of ≅15 deg. and is observed on a face-on geometry, more like the deeply buried 'new type' AGNs found by Ueda et al. We demonstrate the potential power of direct application of such numerical simulations to high-quality broadband spectra to unveil the inner structure of AGNs.

  1. 19F-decoupling of half-integer spin quadrupolar nuclei in solid-state NMR: application of frequency-swept decoupling methods.

    Science.gov (United States)

    Chandran, C Vinod; Hempel, Günter; Bräuniger, Thomas

    2011-09-01

    In solid-state NMR studies of minerals and ion conductors, quadrupolar nuclei like (7)Li, (23)Na or (133)Cs are frequently situated in close proximity to fluorine, so that application of (19)F decoupling is beneficial for spectral resolution. Here, we compare the decoupling efficiency of various multi-pulse decoupling sequences by acquiring (19)F-decoupled (23)Na-NMR spectra of cryolite (Na(3)AlF(6)). Whereas the MAS spectrum is only marginally affected by application of (19)F decoupling, the 3Q-filtered (23)Na signal is very sensitive to it, as the de-phasing caused by the dipolar interaction between sodium and fluorine is three-fold magnified. Experimentally, we find that at moderate MAS speeds, the decoupling efficiencies of the frequency-swept decoupling schemes SW(f)-TPPM and SW(f)-SPINAL are significantly better than the conventional TPPM and SPINAL sequences. The frequency-swept sequences are therefore the methods of choice for efficient decoupling of quadrupolar nuclei with half-integer spin from fluorine. PMID:21856132

  2. Nuclear spectroscopy by radioactivity. Study of nuclei adjacent to the 82 neutron closed shell and application to fission

    International Nuclear Information System (INIS)

    Chemical separation techniques have been developed which make it possible to obtain a certain number of isotopes presenting anomalies in the fission efficiencies (near the magic shell N=82). A short description is given of the fission phenomenon by analysing the selection of isotopes investigated; it is shown how it was possible to explain the results by means of computers and the various chemical separations perfected are described. Thus a study was made of the 144La direct γ spectrum. It was shown that the anomalies in the fission efficiencies of certain nuclei are apparent only. Hence, it is the presence of isomers and the distribution of the corresponding efficiency between two isomers which are the cause of the apparent weakness of the efficiency of 134I, 136I and 136Cs, and of certain isotopes of Nb(Z=41). The nuclear spectrometry of nuclei of the area N=82 has made it possible to extend the existence of a metastable state to 136Xe and 138Ba. The value of the energies of the first 2+, 4+, 6+ levels and the half life duration of the 6+ metastable state are given. The discussion of the results and of the models show that the interpretation of the 0+, 2+, 4+ of the 82 neutron nuclei by means of a two quasi-particle (protons) model gives a fairly satisfactory description of the various experimental events: elastic scattering, gamma spectrometry and proton transfer reactions; on the other hand the interpretation of higher energy levels, requires the use of more complicated configurations

  3. Application of the sextic oscillator with centrifugal barrier and the spheroidal equation for some X(5) candidate nuclei

    CERN Document Server

    Raduta, A A

    2013-01-01

    The eigenvalue equation associated to the Bohr-Mottelson Hamiltonian is considered in the intrinsic reference frame and amended by replacing the harmonic oscillator potential in the $\\beta$ variable with a sextic oscillator potential with centrifugal barrier plus a periodic potential for the $\\gamma$ variable. After the separation of variables, the $\\beta$ equation is quasi-exactly solved, while the solutions for the $\\gamma$ equation are just the angular spheroidal functions. An anharmonic transition operator is used to determine the reduced E2 transition probabilities. The formalism is conventionally called the Sextic and Spheroidal Approach (SSA) and applied for several X(5) candidate nuclei: $^{176,178,180,188,190}$Os, $^{150}$Nd, $^{170}$W, $^{156}$Dy, $^{166,168}$Hf. The SSA predictions are in good agreement with the experimental data of the mentioned nuclei. The comparison of the SSA results with those yielded by other models, such as X(5) \\cite{Iache9}, Infinite Square Well (ISW) \\cite{Raduta}, and Da...

  4. Review of metastable states in heavy nuclei

    Science.gov (United States)

    Dracoulis, G. D.; Walker, P. M.; Kondev, F. G.

    2016-07-01

    The structure of nuclear isomeric states is reviewed in the context of their role in contemporary nuclear physics research. Emphasis is given to high-spin isomers in heavy nuclei, with A≳ 150 . The possibility to exploit isomers to study some of the most exotic nuclei is a recurring theme. In spherical nuclei, the role of octupole collectivity is discussed in detail, while in deformed nuclei the limitations of the K quantum number are addressed. Isomer targets and isomer beams are considered, along with applications related to energy storage, astrophysics, medicine, and experimental advances.

  5. The AzTEC mm-Wavelength Camera

    CERN Document Server

    Wilson, G W; Perera, T A; Scott, K S; Ade, P A R; Bock, J J; Glenn, J; Golwala, S R; Kim, S; Kang, Y; Lydon, D; Mauskopf, P D; Predmore, C R; Roberts, C M; Souccar, K; Yun, M S

    2008-01-01

    AzTEC is a mm-wavelength bolometric camera utilizing 144 silicon nitride micromesh detectors. Herein we describe the AzTEC instrument architecture and its use as an astronomical instrument. We report on several performance metrics measured during a three month observing campaign at the James Clerk Maxwell Telescope, and conclude with our plans for AzTEC as a facility instrument on the Large Millimeter Telescope.

  6. The interaction of two nonplanar solitary waves in electron-positron-ion plasmas: An application in active galactic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    EL-Labany, S. K.; Khedr, D. M. [Department of Physics, Faculty of Science, Damietta University, Damietta El-Gedida 34517 (Egypt); El-Shamy, E. F. [Department of Physics, Faculty of Science, Damietta University, Damietta El-Gedida 34517 (Egypt); Department of Physics, College of Science, King Khalid University, P.O. 9004, Abha (Saudi Arabia); Sabry, R. [Department of Physics, Faculty of Science, Damietta University, Damietta El-Gedida 34517 (Egypt); Department of Physics, College of Science and Humanitarian Studies, Salman bin Abdulaziz University, Alkharj (Saudi Arabia)

    2013-01-15

    In the present research paper, the effect of bounded nonplanar (cylindrical and spherical) geometry on the interaction between two nonplanar electrostatic solitary waves (NESWs) in electron-positron-ion plasmas has been studied. The extended Poincare-Lighthill-Kuo method is used to obtain nonplanar phase shifts after the interaction of the two NESWs. This study is a first attempt to investigate nonplanar phase shifts and trajectories for NESWs in a two-fluid plasma (a pair-plasma) consisting of electrons and positrons, as well as immobile background positive ions in nonplanar geometry. The change of phase shifts and trajectories for NESWs due to the effect of cylindrical geometry, spherical geometry, the physical processes (either isothermal or adiabatic), and the positions of two NESWs are discussed. The present investigation may be beneficial to understand the interaction between two NESWs that may occur in active galactic nuclei.

  7. Formation of Turbulent Cones in Accretion Disk Outflows and Application to Broad Line Regions of Active Galactic Nuclei

    CERN Document Server

    Poludnenko, A Y; Frank, A

    2002-01-01

    We consider the stability of an accretion disk wind to cloud formation when subject to a central radiation force. For a vertical launch velocity profile that is Keplerian or flatter and the presence of a significant radiation pressure, the wind flow streamlines cross in a conical layer. We argue that such regions are highly unstable, and are natural sites for supersonic turbulence and, consequently, density compressions. We suggest that combined with thermal instability these will all conspire to produce clouds. Such clouds can exist in dynamical equilibrium, constantly dissipating and reforming. As long as there is an inner truncation radius to the wind, our model emerges with a biconical structure similar to that inferred by Elvis (2000) for the broad line region (BLR) of active galactic nuclei (AGN). Our results may also apply to other disk-wind systems.

  8. Comparison of DD, DT and Cf-252 neutron excitation of light and medium mass nuclei for field PGNAA applications

    Energy Technology Data Exchange (ETDEWEB)

    Seabury, E.H. [Idaho National Laboratory, P.O. Box 1625 Idaho Falls, ID 8341-3840 (United States)]. E-mail: Edward.Seabury@inl.gov; Blackburn, B.W. [Idaho National Laboratory, P.O. Box 1625 Idaho Falls, ID 8341-3840 (United States); Chichester, D.L. [Idaho National Laboratory, P.O. Box 1625 Idaho Falls, ID 8341-3840 (United States); Wharton, C.J. [Idaho National Laboratory, P.O. Box 1625 Idaho Falls, ID 8341-3840 (United States); Caffrey, A.J. [Idaho National Laboratory, P.O. Box 1625 Idaho Falls, ID 8341-3840 (United States)

    2007-08-15

    Prompt Gamma Ray Neutron activation analysis can offer significant cost and safety advantages in the identification of explosives and toxic chemicals. As an example, the US military examined over a thousand suspect chemical munitions with Idaho National Laboratory's PINS Chemical Assay System last year. PGNAA requires, of course, a neutron source to excite the atomic nuclei of the item under test via neutron capture and inelastic neutron scattering reactions and the choice of neutron source can drastically affect PGNAA system performance. We have carried out Monte Carlo and laboratory experiments comparing DD, DT and Cf-252 neutrons incident on light and medium mass chemical elements, toward optimizing the design of future neutron-generator-based PGNAA systems for field use. We report the excitation of (n, {gamma}) and (n, n') gamma rays from these elements by each type of neutron source.

  9. Comparison of DD, DT and Cf-252 neutron excitation of light and medium mass nuclei for field PGNAA applications

    International Nuclear Information System (INIS)

    Prompt Gamma Ray Neutron activation analysis can offer significant cost and safety advantages in the identification of explosives and toxic chemicals. As an example, the US military examined over a thousand suspect chemical munitions with Idaho National Laboratory's PINS Chemical Assay System last year. PGNAA requires, of course, a neutron source to excite the atomic nuclei of the item under test via neutron capture and inelastic neutron scattering reactions and the choice of neutron source can drastically affect PGNAA system performance. We have carried out Monte Carlo and laboratory experiments comparing DD, DT and Cf-252 neutrons incident on light and medium mass chemical elements, toward optimizing the design of future neutron-generator-based PGNAA systems for field use. We report the excitation of (n, γ) and (n, n') gamma rays from these elements by each type of neutron source

  10. Comparison of DD, DT and Cf-252 neutron excitation of light and medium mass nuclei for field PGNAA applications

    Science.gov (United States)

    Seabury, E. H.; Blackburn, B. W.; Chichester, D. L.; Wharton, C. J.; Caffrey, A. J.

    2007-08-01

    Prompt Gamma Ray Neutron activation analysis can offer significant cost and safety advantages in the identification of explosives and toxic chemicals. As an example, the US military examined over a thousand suspect chemical munitions with Idaho National Laboratory's PINS Chemical Assay System last year. PGNAA requires, of course, a neutron source to excite the atomic nuclei of the item under test via neutron capture and inelastic neutron scattering reactions and the choice of neutron source can drastically affect PGNAA system performance. We have carried out Monte Carlo and laboratory experiments comparing DD, DT and Cf-252 neutrons incident on light and medium mass chemical elements, toward optimizing the design of future neutron-generator-based PGNAA systems for field use. We report the excitation of (n, γ) and (n, n‧) gamma rays from these elements by each type of neutron source.

  11. Angular momentum projection of cranked Hartree-Fock states: Application to terminating bands in A∼44 nuclei

    International Nuclear Information System (INIS)

    We present the first systematic calculations based on the angular momentum projection of cranked Slater determinants. We propose the Iy→I scheme, by which one projects the angular momentum I from the one-dimensional cranked state constrained to the average spin projection of y>=I. Calculations performed for the rotational band in 46Ti show that the AMP Iy→I scheme offers a natural mechanism for correcting the cranking moment of inertia at low spins and shifting the terminating state up by ∼2 MeV, in accordance with data. We also apply this scheme to high-spin states near the band termination in A∼44 nuclei and compare results thereof with experimental data, shell-model calculations, and results of the approximate analytical symmetry-restoration method proposed previously

  12. Application of an Extended Random Phase Approximation on Giant Resonances in Light, Medium and Heavy Mass Nuclei

    CERN Document Server

    Tselyaev, V; Speth, J; Krewald, S; Reinhard, P -G

    2016-01-01

    We present results of the time blocking approximation (TBA) on giant resonances in light, medium and heavy mass nuclei. The TBA is an extension of the widely used random-phase approximation (RPA) adding complex configurations by coupling to phonon excitations. A new method for handling the single-particle continuum is developed and applied in the present calculations. We investigate in detail the dependence of the numerical results on the size of the single particle space and the number of phonons as well as on nuclear matter properties. Our approach is self-consistent, based on an energy-density functional of Skyrme type where we used seven different parameter sets. The numerical results are compared with experimental data.

  13. Angular momentum projection of cranked Hartree-Fock states: Application to terminating bands in A~44 nuclei

    CERN Document Server

    Zdunczuk, H; Dobaczewski, J; Kosmulski, M

    2007-01-01

    We present the first systematic calculations based on the angular-momentum projection of cranked Slater determinants. We propose the Iy --> I scheme, by which one projects the angular momentum I from the 1D cranked state constrained to the average spin projection of =I. Calculations performed for the rotational band in 46Ti show that the AMP Iy --> I scheme offers a natural mechanism for correcting the cranking moment of inertia at low-spins and shifting the terminating state up by ~2 MeV, in accordance with data. We also apply this scheme to high-spin states near the band termination in A~44 nuclei, and compare results thereof with experimental data, shell-model calculations, and results of the approximate analytical symmetry-restoration method proposed previously.

  14. Coupled-Cluster Theory for Nuclei

    International Nuclear Information System (INIS)

    The quantum-many body problem spans numerous scientific disciplines ranging from condensed matter to quantum dots, to high-temperature superconductors, and to nuclei. In these proceedings, we discuss the development of coupled-cluster techniques and their application to nuclei. We concentrate specifically on calculations pertaining to the ground- and excited-state properties of 4He and 16O

  15. Modeling in vivo corrosion of AZ31 as temporary biodegradable implants. Experimental validation in rats

    International Nuclear Information System (INIS)

    In this paper, two complementary approaches, mathematical modeling and experimental results are combined to identify variables that affect the in vivo biodegradation of magnesium implants. The in vivo corrosion behavior of AZ31 alloy proposed for temporary applications as fixation of bone fractures has been modeled solving the Laplace equation by finite element method (FEM). Bar-shaped AZ31 implants of 1 mm diameter and 20 mm length were inserted in Wistar rat femurs with and without a fracture. The presence of gas around AZ31 implants inside the femurs has been detected in situ at the epiphysis and in fractured areas by computerized tomography (CT). Examining some in vivo conditions, the model confirms that magnesium-alloy devices have different biodegradation behavior, depending on the thickness of electrolyte at the implantation site and can be used for predicting the biodegradation behavior. - Highlights: • Modeling of AZ31 corrosion by solving the Laplace by finite element method • Electrolyte thickness is a key factor in the in vivo corrosion of magnesium alloys. • A critical thickness below which corrosion is focused around impurities is identified. • The critical value is less evident in a material with a high number of impurities. • Experimental and numerical results explain the biodegradation of magnesium implants

  16. Rapid coating of AZ31 magnesium alloy with calcium deficient hydroxyapatite using microwave energy.

    Science.gov (United States)

    Ren, Yufu; Zhou, Huan; Nabiyouni, Maryam; Bhaduri, Sarit B

    2015-04-01

    Due to their unique biodegradability, magnesium alloys have been recognized as suitable metallic implant materials for degradable bone implants and bioresorbable cardiovascular stents. However, the extremely high degradation rate of magnesium alloys in physiological environment has restricted its practical application. This paper reports the use of a novel microwave assisted coating technology to improve the in vitro corrosion resistance and biocompatibility of Mg alloy AZ31. Results indicate that a dense calcium deficient hydroxyapatite (CDHA) layer was uniformly coated on a AZ31 substrate in less than 10min. Weight loss measurement and SEM were used to evaluate corrosion behaviors in vitro of coated samples and of non-coated samples. It was seen that CDHA coatings remarkably reduced the mass loss of AZ31 alloy after 7days of immersion in SBF. In addition, the prompt precipitation of bone-like apatite layer on the sample surface during immersion demonstrated a good bioactivity of the CDHA coatings. Proliferation of osteoblast cells was promoted in 5days of incubation, which indicated that the CDHA coatings could improve the cytocompatibility of the AZ31 alloy. All the results suggest that the CDHA coatings, serving as a protective layer, can enhance the corrosion resistance and biological response of magnesium alloys. Furthermore, this microwave assisted coating technology could be a promising method for rapid surface modification of biomedical materials. PMID:25686961

  17. Computer simulation of the leaching and washing of waste in tanks C-106, AY-102, AZ-101, and AZ-102

    Energy Technology Data Exchange (ETDEWEB)

    MacLean, G.T.

    1997-05-01

    The waste in underground storage tanks C-106, AY-102, AZ-101, and AZ-102 will be used to prepare feed material for the proposed high level waste vitrification demonstration plant at Hanford. A chemical process simulation computer program called the Environment Simulation Program (ESP) was used to estimate the compositions and quantities of this waste and the products after pretreatment processing. The amount of precipitated material in Tank C-106 predicted to be dissolved by sluicing is 27 wt.%. The amount of precipitated material predicted to be dissolved by mild leaching is about 30% for the C-106 and AY-102 combined waste and about 50% for AZ-101, and 35% for AZ-102 wastes. The predicted caustic solution raw material requirements for leaching are 158 m{sup 3} for C-106 and AY-102, 60 m{sup 3} for AZ-101, and 146 m{sup 3} for AZ-102, all as 50 wt.% NAOH.

  18. Computer simulation of the leaching and washing of waste in tanks C-106, AY-102, AZ-101, and AZ-102

    International Nuclear Information System (INIS)

    The waste in underground storage tanks C-106, AY-102, AZ-101, and AZ-102 will be used to prepare feed material for the proposed high level waste vitrification demonstration plant at Hanford. A chemical process simulation computer program called the Environment Simulation Program (ESP) was used to estimate the compositions and quantities of this waste and the products after pretreatment processing. The amount of precipitated material in Tank C-106 predicted to be dissolved by sluicing is 27 wt.%. The amount of precipitated material predicted to be dissolved by mild leaching is about 30% for the C-106 and AY-102 combined waste and about 50% for AZ-101, and 35% for AZ-102 wastes. The predicted caustic solution raw material requirements for leaching are 158 m3 for C-106 and AY-102, 60 m3 for AZ-101, and 146 m3 for AZ-102, all as 50 wt.% NAOH

  19. Nuclei in the Skyrme model

    International Nuclear Information System (INIS)

    The application of the Skyrme model to nuclear physics is discussed. A new approach is presented in which nuclei are identified with static soliton solutions in the appropriate topological sector. When this approach is applied to the deuteron, it yields automatically the correct spin, isospin, and parity quantum numbers. 4 refs

  20. Hot deformation behavior and dynamic recrystallization kinetics of AZ61 and AZ61 + Sr magnesium alloys

    Directory of Open Access Journals (Sweden)

    S. Aliakbari Sani

    2016-06-01

    Full Text Available In this study, the effect of strontium addition on hot deformation of AZ61 alloy was investigated by hot compression tests. A reference alloy (AZ61 and an Sr-containing alloy (AZ61 + Sr was cast while their average initial grain size were supposed to be about 140 and 40 µm, respectively. In AZ61 + Sr alloy, the Sr-containing precipitations were stable at homogenization temperature. Analysing the hot compression curves, it was revealed that dynamic recrystallization phenomenon had occurred and controlled the thermomechanical behaviour of the alloys. The derived constitutive equations showed that the hot deformation parameters (n and Q in AZ61 + Sr alloy is smaller than those of AZ61 alloy; this can be related to the small initial grain size and the lower amounts of solute aluminium atoms. The analysis of DRX kinetics along with the micrographs of the deformed microstructures showed that at the same condition the development of DRXed microstructure in AZ61 + Sr alloy was faster than AZ61 alloy. The increased recrystallized microstructure was interpretated to be attributed to (1 the more grain boundaries present and (2 the existance of the Al-Mg-Sr precipitations assisted the PSN mechanism. Also, the attenuated intensity of the basal texture of AZ61 + Sr was related to the DRX fraction of microstructure.

  1. Isobar excitations in nuclei

    International Nuclear Information System (INIS)

    This paper covers the following aspects of isobar excitations in nuclei: Nuclear spin response; Electromagnetic probes; Pion-nuclear reactions; Baryon charge exchange reactions; Charge exchange reactions on nuclei; and Exclusive spectra

  2. Theoretical models for exotic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Sagawa, Hiroyuki [RIKEN Nishina Center, Saitama (Japan); University of Aizu, Center for Mathematics and Physics, Fukushima (Japan); Hagino, Kouichi [Tohoku University, Department of Physics, Sendai (Japan); Tohoku University, Research Center for Electron Photon Science, Sendai (Japan); National Astronomical Observatory of Japan, Tokyo (Japan)

    2015-08-15

    We review various theoretical models which have been used to study the properties of the ground state and excited states of nuclei close to and beyond the neutron and proton drip lines. The validity and limitations of these models are discussed with applications to recent experimental findings such as di-neutron correlations in Borromian nuclei, the soft dipole excitations, direct two-neutron and two-proton decays, and odd-even staggerings of reaction cross sections. The role of isoscalar spin-triplet pairing interaction is also pointed out in the low-lying energy spectra as well as the spin- and isospin-dependent decay rates for N = Z and N = Z + 2 nuclei with mass A < 60. A characteristic feature of the Coulomb energy displacement of the Borromian nucleus {sup 11}Li is discussed in connection to the energies of isobaric analogue states (IAS) of T = 5/2 multiples in the A = 11 systems. (orig.)

  3. Az élelmiszerárak volatilitása az új tagországokban

    OpenAIRE

    Jámbor, Attila

    2014-01-01

    A mezőgazdasági piaci szereplők és a döntéshozók számára kulcskérdés az élelmiszerárak mozgásának és tényezőinek ismerete, hogy kiszámíthatóbbá tegyék azokat a jövőben. Az 1970-es évek élelmiszerválsága óta nem voltak olyan magasak, és nem ingadoztak olyan mértékben az élelmiszerárak, mint manapság (Sumner [2009]). Habár a volatilitás témakörét könyvtárnyi szakirodalom elemzi, azok nagy része az ipari termékekre vagy pénzügyi piacokra koncentrál, míg a mezőgazdasági és élelmiszer-pia...

  4. Joining of AZ31 and AZ91 Mg alloys by friction stir welding

    Directory of Open Access Journals (Sweden)

    B. Ratna Sunil

    2015-12-01

    Full Text Available Two dissimilar magnesium (Mg alloy sheets, one with low aluminium (AZ31 and another with high aluminium (AZ91 content, were successfully joined by friction stir welding (FSW. The effect of process parameters on the formation of hot cracks was investigated. A sound metallurgical joint was obtained at optimized process parameters (1400 rpm with 25 mm/min feed which contained fine grains and distributed β (Mg17Al12 phase within the nugget zone. An increasing trend in the hardness measurements has also confirmed more amount of dissolution of aluminium within the nugget zone. A sharp interface between nugget zone and thermo mechanical affected zone (TMAZ was clearly noticed at the AZ31 Mg alloy side (advancing but not on the AZ91 Mg alloy side (retreating. From the results it can be concluded that FSW can be effectively used to join dissimilar metals, particularly difficult to process metals such as Mg alloys, and hot cracking can be completely eliminated by choosing appropriate process parameters to achieve sound joint.

  5. Entrevista a Maravillas Díaz

    OpenAIRE

    Vernia Carrasco, Anna Mercedes

    2012-01-01

    Maravillas Díaz es Doctora en Filosofía y Ciencias de la Educación y Profesora Titular del Área de Didáctica de la Música en la Universidad del País Vasco. Autora de diversas publicaciones en libros y revistas especializadas. Ha participado en numerosos Comités Científicos nacionales e internacionales como evaluadora experta. Ha impartido numerosas ponencias como profesora invitada y dirigido congresos y jornadas destacando la dirección de la XXVI Conferencia de la International Socie...

  6. Tank 241-AZ-101 and tank 241-AZ-102, airlift circulator operation vapor sampling and analysis plan

    International Nuclear Information System (INIS)

    This sampling and analysis plan (SAP) identifies characterization objectives pertaining to sample collection, laboratory analytical evaluation, and reporting requirements for vapor samples obtained during the operation of the tank 241-AZ-101 and 241-AZ-102 airlift circulators (ALCs). The purpose of the ALC operation is to support portions of the operational test procedure (OTP) for Project W-030 (OTP-W030-001) and to perform functional test in support of Project W-151. Project W-030 is the 241-A-702 ventilation upgrade project (241-AZ-702) and Project W-151 is the 241-AZ-101 Mixer Pump Test. The functional tests will check the operability of the tank 241-AZ-101 ALCs. Process Memo's No.2E98-082 and No.2E99-001 (LMHC 1999a, LMHC 1999b) direct the operation of the ALCs and the Industrial Hygiene monitoring respectively. A series of tests will be conducted in which the ALCs in tanks 241-AZ-101 and 241-AZ-102 will be operated at different air flow rates. Vapor samples will be obtained to determine constituents that may be present in the tank headspace during ALC operation at tanks 241-AZ-101 and 241-AZ-102 as the waste is disturbed. During the testing, vapor samples will be obtained from the headspace of tanks 241-AZ-101 and 241-AZ-102 via the unused port on the standard hydrogen monitoring system (SHMS). Results will be used to provide the waste feed delivery program with environmental air permitting data for tank waste disturbing activities. Because of radiological concerns, the samples will be filtered for particulates. It is recognized that this may remove some organic compounds

  7. ANALYSIS RESULTS FOR BUILDING 241 702-AZ A TRAIN

    Energy Technology Data Exchange (ETDEWEB)

    DUNCAN JB; FRYE JM; COOKE CA; LI SW; BROCKMAN FJ

    2006-12-13

    This report presents the analyses results for three samples obtained under RPP-PLAN-28509, Sampling and Analysis Plan for Building 241 702-AZ A Train. The sampling and analysis was done in response to problem evaluation request number PER-2004-6139, 702-AZ Filter Rooms Need Radiological Cleanup Efforts.

  8. ANALYSIS RESULTS FOR BUILDING 241 702-AZ A TRAIN

    International Nuclear Information System (INIS)

    This report presents the analyses results for three samples obtained under RPP-PLAN-28509, Sampling and Analysis Plan for Building 241 702-AZ A Train. The sampling and analysis was done in response to problem evaluation request number PER-2004-6139, 702-AZ Filter Rooms Need Radiological Cleanup Efforts

  9. 241-AZ Farm Annulus Extent of Condition Baseline Inspection

    Energy Technology Data Exchange (ETDEWEB)

    Engeman, Jason K.; Girardot, Crystal L.; Vazquez, Brandon J.

    2013-05-15

    This report provides the results of the comprehensive annulus visual inspection for tanks 241- AZ-101 and 241-AZ-102 performed in fiscal year 2013. The inspection established a baseline covering about 95 percent of the annulus floor for comparison with future inspections. Any changes in the condition are also included in this document.

  10. Mechanical properties and microstructures of a wrought AZ91 alloy

    Institute of Scientific and Technical Information of China (English)

    YAN Yunqi; ZHANG Tingjie; ZHOU Lian; DENG Ju

    2004-01-01

    Effects of hot plastic deformation on microstructures and tensile properties of AZ91 alloy were investigated. Compared with as-T4 microstructures, the as-extruded samples of AZ91 alloy with fine grains exhibit better strength and ductility due to dynamic recrystallization. The succeeded rotation forging also provides finer grains while the strength in creases, but the elongation decreases. Simultaneously, wrought AZ91 alloy shows more balance properties than as-T4 condition ones. An interesting elongation of 228.5% is attained in the as-extruded AZ91 alloy in spite of the coarse grains with the size of 85 μm. The two-step method enhances the superplastic property of AZ91 alloy. The microstructure is still keep ing the same scale of grains after superplastic testing.

  11. Azúcar y enfermedades cardiovasculares

    Directory of Open Access Journals (Sweden)

    Luis Gómez Morales

    2013-07-01

    Full Text Available Las enfermedades cardiovasculares constituyen la principal causa de muerte en la población española y podría existir una relación entre la prevalencia de las mismas y el consumo excesivo de azúcar. En estos últimos años, los investigadores se han centrado en las propiedades de estos nutrientes. Aunque existen muchos estudios que analizan dicha asociación, los resultados no son unánimes. En cualquier caso, existe fundamento suficiente para diseñar estrategias de salud pública de cara a reducir el consumo de bebidas azucaradas, como parte de un estilo de vida saludable. Por lo tanto, la cuestión que abordamos es: ¿la ingesta de azúcar, en cuantía abundante, se asocia un mayor riesgo de padecer enfermedad cardiovascular? Para ello utilizamos como eje de la discusión el modelo de análisis DAFO.

  12. Skyrmions in nuclei

    International Nuclear Information System (INIS)

    The applications of skyrmions to the derivation of the nucleon-nucleon force are now over a dozen years old, and this occasion is used to assess the degree of success of the endeavor. A very brief review is given of the use of skyrmions for determining single-baryon properties. Then their use for two-nucleon systems is described, with attention to the use of the product ansatz, the full structure of the lagrangian, baryon resonance admixtures, dilatons, and exact solutions for the B=2 system in order to find the sources of attraction in the central potential. We briefly address possible insights into the behavior of the nucleon in nuclei achieved from the skyrmion approach. (author)

  13. Electron scattering off nuclei

    International Nuclear Information System (INIS)

    Two recently developed aspects related to the scattering of electrons off nuclei are presented. On the one hand, a model is introduced which emphasizes the relativistic aspects of the problem in the impulse approximation, by demanding strict maintenance of the algebra of the Poincare group. On the other hand, the second model aims at a more sophisticated description of the nuclear response in the case of collective excitations. Basically, it utilizes the RPA formalism with a new development which enables a more careful treatment of the states in the continuum as is the case for the giant resonances. Applications of both models to the description of elastic scattering, inelastic scattering to discrete levels, giant resonances and the quasi-elastic region are discussed. (Author)

  14. Improved Corrosion Resistance of Magnesium Alloys AZ31 and AZ91HP by High Current Pulsed Electron Beam Treatment

    Institute of Scientific and Technical Information of China (English)

    HAO Sheng- zhi; GAO Bo; ZHOU Ji-yang; DONG Chuang

    2004-01-01

    Surface treatment of magnesium alloys AZ31 and AZ91HP by a high current pulsed electron beam (HCPEB)was investigated in the present paper. The corrosion resistance of treated samples was tested in a 5% (wt%) NaCl solution,showing remarkably improvement as manifested by polarization curves. According to EPMA analysis, the intermetallic Mg17Al12 in the surface layer of AZ91HP sample almost disappeared after the treatment of HCPEB, leaving the surface layer in a state of supersaturated solid solution. Both the augmentation of aluminum content and the formation of supersaturated structure in the surface layer are believed to contribute to the improved corrosion resistance of AZ31 and AZ91HP.

  15. Improved Corrosion Resistance of Magnesium Alloys AZ31 and AZ91HP by High Current Pulsed Electron Beam Treatment

    Institute of Scientific and Technical Information of China (English)

    HAOSheng-zhi; GAOBo; ZHOUJi-yang; DONGChuang

    2004-01-01

    Surface treatment of magnesium alloys AZ31 and AZ91HP by a high current pulsed electron beam (HCPEB) was investigated in the present paper. The corrosion resistance of treated samples was tested in a 5% (wt%) NaCl solution, showing remarkably improvement as manifested by polarization curves. According to EPMA analysis, the intermetallic Mg17Al12 in the surface layer of AZ91HP sample almost disappeared after the treatment of HCPEB, leaving the surface layer in a state of supersaturated solid solution. Both the augmentation of aluminum content and the formation of supersaturated structure in the surface layer are believed to contribute to the improved corrosion resistance of AZ31 and AZ91HP.

  16. Structure and Corrosion Resistance of Microarc Oxidation Coatings on AZ91D Magnesium Alloy

    Institute of Scientific and Technical Information of China (English)

    Cui Shihai; Han Jianmin; Li Weijing; Li Ronghua; Zhu Xiaowen; Wang Jinhua

    2004-01-01

    Magnesium alloys are widely used as shells of 3C (computer, mobile phone and consumer electronics) equipments for its impressive mechanical and physical properties, such as low density, good resistance to electromagnetic radiation, suitable for high pressure diecasting and easily recycling, etc. But poor corrosion resistance confines its extensively application. In this paper, protective coatings was successfully prepared on AZ91D magnesium alloys by micro-arc oxidation (MAO) and painting process. Microstructures and phases of MAO coatings were invesgated with scanning electron microscope (SEM) and X-Ray diffractometer. Mechanical properties of MAO coating, such as adhesive force and corrosion resistance, were also tested. Results showed that MAO coatings were a good base for painting process. MAO coatings with paint have good adhesive properties to base metal and excellent corrosion resistance. Micro-arc oxidation with painting process is a good kind of surface treatment to improve the corrosion resistance of mobile phone shell made of AZ91D magnesium alloys.

  17. Magnetic force improvement and parameter optimization for magnetic abrasive polishing of AZ31 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The magnetic force acting on workpieee to be machined plays a significantly important role in magnetic abrasive polishing process.But in a case of polishing nonferrous materials,the strength of magnetic force is very low and it leads lower polishing efficiency.The magnesium alloy that has superior mechanical properties for industrial application such as a lightweight and high specific strength is one of the most famous nonferrous materials.An improving strategy of the magnetic force for me AZ31 magnesium alloy installed with a permanent magnet was proposed and experimental verification Was carded out.For the proposed strategy,the effect of process parameters on the surface roughness of the AZ31 magnesium alloy Was evaluated by a design of experimental method.

  18. Using two-pass friction stir processing to produce nanocrystalline microstructure in AZ61 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Despite their interesting properties,nanostructured materials have found limited use as a result of the cost of preparation and the difficulty in scaling up.Herein,a two-pass friction stir processing(FSP)technique is employed to refine grain sizes to a nanoscale.Nanocrystalline AZ61 Mg alloy with an av-erage grain size of less than 100nm was successfully obtained using FSP.Corresponding to this,the highest microhardness of the nano-grained region reached triple times that of AZ61 substrate.In prin-ciple,by applying multiple overlapping passes,it should be possible to produce any desired size thin sheet of nanostructure using this technique.We expect that the FSP technique may pave a way to large-scale structural applications of nanostructured metals and alloys.

  19. Corrosion resistance of a composite polymeric coating applied on biodegradable AZ31 magnesium alloy.

    Science.gov (United States)

    Zomorodian, A; Garcia, M P; Moura e Silva, T; Fernandes, J C S; Fernandes, M H; Montemor, M F

    2013-11-01

    The high corrosion rate of magnesium alloys is the main drawback to their widespread use, especially in biomedical applications. There is a need for developing new coatings that provide simultaneously corrosion resistance and enhanced biocompatibility. In this work, a composite coating containing polyether imide, with several diethylene triamine and hydroxyapatite contents, was applied on AZ31 magnesium alloys pre-treated with hydrofluoric acid by dip coating. The coated samples were immersed in Hank's solution and the coating performance was studied by electrochemical impedance spectroscopy and scanning electron microscopy. In addition, the behavior of MG63 osteoblastic cells on coated samples was investigated. The results confirmed that the new coatings not only slow down the corrosion rate of AZ31 magnesium alloys in Hank's solution, but also enhance the adhesion and proliferation of MG63 osteoblastic cells, especially when hydroxyapatite nanoparticles were introduced in the coating formulation. PMID:23454214

  20. Test-retest reliability of [{sup 11}C]AZ10419369 binding to 5-HT{sub 1B} receptors in human brain

    Energy Technology Data Exchange (ETDEWEB)

    Nord, Magdalena; Finnema, Sjoerd J.; Schain, Martin; Halldin, Christer; Farde, Lars [Karolinska Institutet, Center for Psychiatric Research, R5:00, Karolinska University Hospital, Department of Clinical Neuroscience, Stockholm (Sweden)

    2014-02-15

    [{sup 11}C]AZ10419369 is a recently developed 5-HT{sub 1B} receptor radioligand that is sensitive to changes in endogenous serotonin concentrations in the primate brain. Thus, [{sup 11}C] AZ10419369 may serve as a useful tool in clinical studies of the pathophysiology and pharmacological treatment of diseases related to the serotonin system, such as depression and anxiety disorders. The aim of this study was to evaluate the test-retest reliability of [{sup 11}C]AZ10419369. Eight men were examined with PET and [{sup 11}C] AZ10419369 twice on the same day. The binding potentials (BP{sub ND}) of [{sup 11}C]AZ10419369 in selected serotonergic projection areas and in the raphe nuclei (RN) were determined using the simplified reference tissue model, and for comparison also using a wavelet-aided parametric imaging approach. The BP{sub ND} values obtained from the first and second PET scans were compared by means of descriptive statistics, difference, absolute variability and intraclass correlation coefficient. Similar BP{sub ND} values were obtained with the two methods. The absolute mean differences in BP{sub ND} between PET 1 and PET 2 were less than 3 % in all serotonergic projection regions. Absolute variabilities were low in cortical regions (5 - 7 %), low to moderate (7 - 14 %) in subcortical regions, but higher (20 %) in the RN. The BP{sub ND} of [{sup 11}C]AZ10419369 is highly reproducible in cortical regions and satisfactory in subcortical projection areas. The variability in the RN is higher. Thus larger sample sizes or larger divergences are required to assess a potential difference between subjects or between experimental conditions in this region. (orig.)

  1. Corrosion product layers on magnesium alloys AZ31 and AZ61: Surface chemistry and protective ability

    Energy Technology Data Exchange (ETDEWEB)

    Feliu, S., E-mail: sfeliu@cenim.csic.es; Llorente, I.

    2015-08-30

    Highlights: • Surface chemistry of the corrosion product layers on magnesium alloys. • Influence of the type of alloy on the carbonate surface enrichment. • Relation between surface composition and protection properties. - Abstract: This paper studies the chemical composition of the corrosion product layers formed on magnesium alloys AZ31 and AZ61 following immersion in 0.6 M NaCl, with a view to better understanding their protective action. Relative differences in the chemical nature of the layers were quantified by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive analysis of X-ray (EDX) and low-angle X-ray diffraction (XRD). Corrosion behavior was investigated by Electrochemical Impedance Spectroscopy (EIS) and hydrogen evolution measurement. An inhibitive effect from the corrosion product layers was observed from EIS, principally in the case of AZ31, as confirmed by hydrogen evolution tests. A link was found between carbonate enrichment observed by XPS in the surface of the corrosion product layer, concomitant with the increase in the protective properties observed by EIS.

  2. Corrosion product layers on magnesium alloys AZ31 and AZ61: Surface chemistry and protective ability

    International Nuclear Information System (INIS)

    Highlights: • Surface chemistry of the corrosion product layers on magnesium alloys. • Influence of the type of alloy on the carbonate surface enrichment. • Relation between surface composition and protection properties. - Abstract: This paper studies the chemical composition of the corrosion product layers formed on magnesium alloys AZ31 and AZ61 following immersion in 0.6 M NaCl, with a view to better understanding their protective action. Relative differences in the chemical nature of the layers were quantified by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive analysis of X-ray (EDX) and low-angle X-ray diffraction (XRD). Corrosion behavior was investigated by Electrochemical Impedance Spectroscopy (EIS) and hydrogen evolution measurement. An inhibitive effect from the corrosion product layers was observed from EIS, principally in the case of AZ31, as confirmed by hydrogen evolution tests. A link was found between carbonate enrichment observed by XPS in the surface of the corrosion product layer, concomitant with the increase in the protective properties observed by EIS

  3. Nuclei and quantum worlds

    International Nuclear Information System (INIS)

    This document gathers the slides and their commentaries that have been presented at the conference 'physics and fundamental questions' by P. Chomaz. The author reviews the different quantum aspects of nuclei: tunnel effect, symmetries, magic numbers, wave functions, size, shapes and deformations. The author shows that nuclei are quantum objects of great complexity, their structures are not yet well understood and the study of exotic nuclei will continue bringing valuable information

  4. Facebook Marketing - Fra A-Z

    DEFF Research Database (Denmark)

    Mortensen, Thomas Bøtker

    2009-01-01

    Facebook Marketing – Leverage Social Media to Grow Your Business af Steven Holzner er Facebook Marketing fra A-Z, som kan anbefales til virksomheder, som overvejer at bevæge sig ud i cyber space og afprøve mulighederne for at markedsføre sig dér. Bogen beskriver på hvilke væsentlige punkter...... marketing på Facebook adskiller sig fra traditionel marketing, og gennemgår trin for trin de fundamentale ting, som man skal vide for, at virksomheden kan agere med den tilsigtede effekt i et socialt netværk som Facebook. Og eftersom 34 % af den danske befolkning i dag er hoppet med på Facebook vognen og...... har oprettet en profil på Facebook, er potentialet åbenlyst....

  5. Structure evolution of AZ61 magnesium alloy in SIMA process

    Institute of Scientific and Technical Information of China (English)

    YAN Hong; ZHANG Fa-yun; JIE Xiao-ping

    2005-01-01

    The effect of prior compressive deformation, isothermal temperature and holding time on the structure of AZ61 magnesium alloy fabricated by strain-induced melt activation(SIMA) processing was investigated. The specimens were subjected under deformation ratios of 0%, 22% and 40% and various heat treatment time and temperature regions. The results indicate that the ideal technological parameters of semi-solid AZ61 alloy produced with non-dendrites are recommended as 22% (prior compressive deformation), 595 ℃ (heat treatment temperature) and 40 min(time). The as-cast AZ61 magnesium alloy isn't fit for semi-solid forming.

  6. Variability of Active Galactic Nuclei

    OpenAIRE

    Peterson, Bradley M.

    2001-01-01

    Continuum and emission-line variability of active galactic nuclei provides a powerful probe of microarcsecond scale structures in the central regions of these sources. In this contribution, we review basic concepts and methodologies used in analyzing AGN variability. We develop from first principles the basics of reverberation mapping, and pay special attention to emission-line transfer functions. We discuss application of cross-correlation analysis to AGN light curves. Finally, we provide a ...

  7. Superheavy nuclei and fission barriers

    Science.gov (United States)

    Lu, Bing-Nan; Zhao, Jie; Zhao, En-Guang; Zhou, Shan-Gui

    In this chapter, we will present relativistic mean field (RMF) description of heavy and superheavy nuclei (SHN). We will discuss the shell structure and magic numbers in the mass region of SHN, binding energies and α decay Q values, shapes of ground states and potential energy surfaces and fission barriers. We particularly focus on the multidimensionally-constrained covariant density functional theories (CDFT) and the applications of CDFT to the study of exotic nuclear shapes and fission barriers.

  8. A comparative corrosion behavior of Mg, AZ31 and AZ91 alloys in 3.5% NaCl solution

    Directory of Open Access Journals (Sweden)

    I.B. Singh

    2015-06-01

    Full Text Available The corrosion behavior of Mg, AZ31 and AZ91 has been evaluated in 3.5% NaCl solution using weight loss, electrochemical polarization and impedance measurements. Corrosion rate derived from the weight losses demonstrated the occurrence of steeply fast corrosion reaction on AZ91 alloy after three hours of immersion, indicating the start of galvanic corrosion. An increase of corrosion rate with immersion time was also observed for AZ31 but with lesser extent than AZ91 alloy. Whereas Mg metals showed a decrease of corrosion rate with immersion time, suggesting the formation of a protective layer on their surfaces. In contrast, the corrosion current density (Icorr derived from the Tafel plots, exhibited their corrosion resistances in order of Mg > AZ91 > AZ31. Electrochemical charge transfer resistance (Rct and double layer capacitance measured by electrochemical impedance spectroscopy (EIS, are well in accordance with the measured Icorr. EIS measurements with time and microstructural examination of the corroded and uncorroded samples are helpful in elucidation of results measured by electrochemical polarization.

  9. Cytotoxicity studies of AZ31D alloy and the effects of carbon dioxide on its biodegradation behavior in vitro

    International Nuclear Information System (INIS)

    Magnesium alloys have been advocated as potential artificial bone materials due to their biocompatibility and biodegradability. The understanding of their corrosive mechanism in physiological environments is therefore essential for making application-orientated designs. Thus, this in vitro study was designed to assess the effects of CO2 on corrosive behavior of AZ31D to mimic in vivo special ingredient. Electrochemical technologies accompanied with Scanning electron microscope, Fourier transform infrared, X-ray diffraction, Energy dispersive spectroscopy and hydrogen evolution measurement were employed to analyze corrosive rates and mechanisms of AZ31D. Moreover, the biocompatibility of AZ31D was assessed with a direct cell attachment assay and an indirect cytotoxicity test in different diluted extracts. The ion concentrations in extracts were measured using inductively coupled plasma mass spectrometry to offer explanations on the differences of cell viability in the indirect test. The results of the direct cytotoxicity assay showed that the corrosive rate of AZ31D was too rapid to allow for cell adhesion. Extracts diluted less than 20 times would cause adverse effects on cell proliferation, likely due to excessive ions and gas release. Moreover, the presence of CO2 did not cause significant differences on corrosive behavior of AZ31D according to the results of electrochemical testing and hydrogen evolution measurement. This might be caused by the simultaneous process of precipitation and dissolution of MgCO3 due to the penetration role of CO2. This analysis of corrosive atmospheres on the degradation behavior of magnesium alloys would contribute to the design of more scientific in vitro testing systems in the future. - Highlights: • We evaluate the effects of CO2 on corrosion behavior of magnesium alloys. • We assess the feasibility of commercial AZ31D alloy as potential implants. • CO2 is not the key factor to minimize the gap of in vitro and in vivo

  10. Carbon Nanotube Addition to Simultaneously Enhance Strength and Ductility of Hybrid AZ31/AA5083 Alloy

    OpenAIRE

    Muralidharan Paramsothy; Manoj Gupta; Jimmy Chan; Richard Kwok

    2011-01-01

    AZ31/AA5083 hybrid alloy nanocomposite containing CNT nanoparticle reinforcement was fabricated using solidification processing followed by hot extrusion. The AZ31/AA5083 hybrid alloy nanocomposite exhibited similar grain size to monolithic AZ31/AA5083 hybrid alloy, reasonable CNT nanoparticle distribution, non-dominant (0 0 0 2) texture in the longitudinal direction, and 20% higher hardness than monolithic AZ31/AA5083 hybrid alloy. Compared to monolithic AZ31/AA5083 hybrid alloy (in tension)...

  11. EnviroAtlas - Phoenix, AZ - Atlas Area Boundary

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset shows the boundary of the Phoenix, AZ Atlas Area. It represents the outside edge of all the block groups included in the EnviroAtlas Area....

  12. Laser welding of AZ61 magnesium-based alloys

    Institute of Scientific and Technical Information of China (English)

    Wang Hongying; Li Zhijun; Zhang Yihui

    2006-01-01

    Laser welding of AZ61 magnesium alloys was carried out asing a CO2 laser weldingexperimental system.The welding properties of AZ61 sheets with different thickness were investigated.The effect of processing parameters including laser power, welding speed and protection gas flow was researched.The results show that laser power and welding speed have large effect on the weld width and joint dimensions.Protection gas flow has relatively slight effect on the weld width.The property test of three typical joints indicates that microhardness and tensile strength in weld zone are higher than that of AZ61 base metal.Joints with good appearance and excellent mechanical properties can be produced using CO2 laser welding method.The microstructure with small grains in weld zone is believed to be responsible for the excellent mechanical properties of AZ61 joints.

  13. 75 FR 81190 - Television Broadcasting Services; Yuma, AZ

    Science.gov (United States)

    2010-12-27

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Television Broadcasting Services; Yuma, AZ AGENCY: Federal Communications Commission. ACTION: Dismissal. SUMMARY: The Commission dismisses the petition for rulemaking filed by...

  14. Neutron rich nuclei

    International Nuclear Information System (INIS)

    If some β- emitters are particularly interesting to study in light, medium, and heavy nuclei, another (and also) difficult problem is to know systematically the properties of these neutron rich nuclei far from the stability line. A review of some of their characteristics is presented. How far is it possible to be objective in the interpretation of data is questioned and implications are discussed

  15. Nuclei in high forms

    International Nuclear Information System (INIS)

    The purpose of 1991 Joliot-Curie Summer School is to review the most advances in the understanding of the nuclei physics after the considerable progress in gamma spectroscopy. It covers the following topics: Highly and super-deformed nuclei, nuclear structures, mean-field approach and beyond, fission isomers, nuclear excitations with long lifetime and metal clusters

  16. Espectroscopia por infrarrojo cercano (NIRS: Su aplicación en análisis de jugos de caña de azúcar Near Infrared Spectroscopy (NIRS: Its application in sugarcane juice analysis

    Directory of Open Access Journals (Sweden)

    Silvia Zossi

    Full Text Available La espectroscopia por infrarrojo cercano (NIRS es una metodología instrumental que ha presentado un desarrollo creciente en los últimos años en la industria azucarera mundial. Se la utiliza tanto en centros de investigación como en diversas industrias, por ser una técnica no destructiva, rápida, que no emplea reactivos químicos y que requiere menos mano de obra que los métodos tradicionales empleados en el laboratorio. Por tal motivo, se decidió determinar para las condiciones de la industria azucarera de Tucumán (Argentina, los modelos de calibración más adecuados que permitan predecir los parámetros Brix y pol en jugo de caña de azúcar, mediante el empleo de un equipo NIRS, haciendo posible el reemplazo de los ensayos tradicionales de estos dos parámetros. Los resultados obtenidos de indicadores estadísticos, tales como error estándar de calibración (SEC, error estándar de predicción (SEP y coeficiente de correlación de la calibración (R² fueron altamente satisfactorios en los parámetros evaluados y presentaron concordancia con los valores encontrados en la bibliografía mundial.Near Infrared Spectroscopy (NIRS is an instrumental method which has been increasingly developing during the last few years in sugar industry worldwide. It is employed at research centres and in various industries as well, due to its advantages: it is a non-destructive technique, it is fast and does not require chemical reagents or as much workforce as required by traditional methods used in the laboratory. This work aims to determine the most suitable calibration models to predict Brix and pol in sugarcane juice by means of NIRS equipment, so as to replace traditional methods based on those two parameters. Results obtained from statistical indicators like standard error of calibration (SEC, standard error of prediction (SEP and calibration correlation coefficient (R² were highly satisfactory for the evaluated parameters and showed agreement

  17. Hot Deformation Kinetics of Magnesium Alloy AZ31

    Institute of Scientific and Technical Information of China (English)

    WANG Lingyun; HUANG Guangjie; FAN Yonge; LU Zhiwen; PAN Fusheng

    2006-01-01

    The flow stress at elevated temperatures for magnesium alloy AZ31 was studied using isothermal compression testing. The effect of deformation parameters on the flow stress was studied as well. The kinetics of elevated temperature deformation was expressed by means of some empirical rate equations. The activation parameter has been calculated. A mechanism for the dynamic softening of AZ31 alloy in a hot deformation experiment was identified to be the dynamic recrystallization.

  18. Test Plan for Tank 241-AZ-101 Solubility Screening Tests

    International Nuclear Information System (INIS)

    Tank 241-AZ-101 (101-AZ) has been identified as one of the early tanks to be retrieved for waste pretreatment and immobilization. Retrieval of the tank waste from other tanks may require dilution. This test is to determine the effects of dilution on the mass of solids and their composition, which can be compared with tanks where dilution is required. This test plan gives test instructions, example data sheets, a waste compatibility review, and a waste stream fact sheet

  19. Semi empirical hardness predictive model for AZ91 nanocomposite

    Science.gov (United States)

    Zaidi, N. H. A.; Jamaludin, S. B.; Zaidi, A. M. A.; Ahmad, K. R.

    2016-07-01

    AZ91 nanocomposite was exposed to several heat treatment processes and the effect of precipitation hardening on hardness was studied as a function of time and temperature. The investigation shows the significant of time and temperature are the main role in the precipitation hardening process of the nanocomposite. Kinetics study show a deceptive activation energy of 21 kJ/mol of the AZ91 nanocomposite. A relationship was derived to predict the maximum hardness at given time and temperature.

  20. Flow behaviour of magnesium alloy AZ31B processed by equal-channel angular pressing

    Science.gov (United States)

    Arun, M. S.; Chakkingal, U.

    2014-08-01

    Magnesium alloys are characterised by their low density, high specific strength and stiffness. But, the potential application of Mg is limited by its low room-temperature ductility & formability. Formability can be improved by developing an ultrafine grained (UFG) structure. Equal channel angular pressing (ECAP) is a well known process that can be used to develop an ultrafine grained microstructure. The aim of this study was to investigate the flow behaviour of AZ31B magnesium alloy after ECAP. The specimen was subjected to three passes of ECAP with a die angle of 120° using processing route Bc. The processing temperature was 523 K for the first pass and 423 K for the subsequent two passes. The microstructure characterisation was done. Compression tests of ECAPed and annealed specimens were carried out at strain rates of 0.01 - 1s-1 and deformation temperatures of 200 - 300°C using computer servo-controlled Gleeble-3800 system. The value of activation energy Q and the empirical materials constants of A and n were determined. The equations relating flow stress and Zener-Hollomon parameter were proposed. In the case annealed AZ31, the activation energy was determined to be 154 kJ/mol, which was slightly higher than the activation energy of 144 kJ/mol for ECAPed AZ31.

  1. Preparation of biomimetic hydrophobic coatings on AZ91D magnesium alloy surface

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The hydrophobic coating has been a promising technology for improving surface performance. The surface performance of magnesium alloy has been limited in application. Furthermore, the hydrophobic of magnesium alloy is rarely investigated because magnesium alloy is an active metal alloy. In this paper, inspired by microstructure character of typical plant leaf surface such as lotus, the biomimetic hydrophobic coatings on AZ91D magnesium alloy surface were prepared by means of wet-chemical combining electroless. The samples were immersed into AgNO3 solution in wet-chemical method firstly. Then, biomimetic hydrophobic coatings were prepared by electroless after wet-method pretreatment. The microstructure was observed by SEM and the contact angles were measured by contact angle tester. The results indicated that the biomimetic hydrophobic coatings with uniform crystalline and dense structure could be obtained on AZ91D magnesium alloy surface. The results of contact angle revealed that the biomimetic nano-composite coatings were hydrophobic. The wet-chemical method treatment on the AZ91D magnesium alloy substrate provided a rough microstructure, thus improving adhesion of the coating and the substrate.

  2. Monitoring Lysobacter capsici AZ78 using strain specific qPCR reveals the importance of the formulation for its survival in vineyards.

    Science.gov (United States)

    Segarra, Guillem; Puopolo, Gerardo; Porcel-Rodríguez, Elena; Giovannini, Oscar; Pertot, Ilaria

    2016-02-01

    Survival in the phyllosphere is a critical feature for biofungicides based on non-spore forming bacteria. Moreover, knowledge of their persistence on plants is important to design effective formulations and application techniques. With this scope, the aim of this work was to develop a specific method to monitor the fate in the environment of Lysobacter capsici AZ78, a biocontrol agent of Plasmopara viticola, and to evaluate the contribution of formulation in its persistence on grapevine leaves. A strain-specific primer pair derived from REP-PCR fingerprinting was used in quantitative PCR experiments to track the evolution of L. capsici AZ78 population in vineyards. The population reached between 5 and 6 log10 cells gram of leaf(-1) after application and decreased by more than 100 times in one week. Multiple regression analysis showed that unfavourable temperature was the main environmental factor correlating with the decrease of L. capsici AZ78 persistence on grapevine leaves. Importantly, the use of formulation additives protected L. capsici AZ78 against environmental factors and improved its persistence on the leaves by more than 10 times compared to nude cells. Formulation and the knowledge about the persistence of L. capsici AZ78 in vineyards will be useful to develop commercial biofungicides for foliar application. PMID:26691736

  3. Tank 241-AZ-102 Privatization Push Mode Core Sampling and Analysis Plan

    International Nuclear Information System (INIS)

    This sampling and analysis plan (SAP) identifies characterization objectives pertaining to sample collection, laboratory analytical evaluation, and reporting requirements for samples obtained from tank 241-AZ-102. The purpose of this sampling event is to obtain information about the characteristics of the contents of 241-AZ-102 required to satisfy the Data Quality Objectives For TWRS Privatization Phase I : Confirm Tank TIS An Appropriate Feed Source For High-Level Waste Feed Batch X(HLW DQO) (Nguyen 1999a), Data Quality Objectives For TWRS Privatization Phase 1: Confirm Tank TIS An Appropriate Feed Source For Low-Activity Waste Feed Batch X (LAW DQO) (Nguyen 1999b), Low Activity Waste and High Level Waste Feed Data Quality Objectives (L and H DQO) (Patello et al. 1999) and Characterization Data Needs for Development, Design, and Operation of Retrieval Equipment Developed through the Data Quality Objective Process (Equipment DQO) (Bloom 1996). The Tank Characterization Technical Sampling Basis document (Brown et al. 1998) indicates that these issues, except the Equipment DQO apply to tank 241-AZ-102 for this sampling event. The Equipment DQO is applied for shear strength measurements of the solids segments only. Poppiti (1999) requires additional americium-241 analyses of the sludge segments. Brown et al. (1998) also identify safety screening, regulatory issues and provision of samples to the Privatization Contractor(s) as applicable issues for this tank. However, these issues will not be addressed via this sampling event. Reynolds et al. (1999) concluded that information from previous sampling events was sufficient to satisfy the safety screening requirements for tank 241-AZ-102. Push mode core samples will be obtained from risers 15C and 24A to provide sufficient material for the chemical analyses and tests required to satisfy these data quality objectives. The 222-S Laboratory will extrude core samples, composite the liquids and solids, perform chemical analyses

  4. Adubação do algodoeiro: IV - Ensaios sôbre época de aplicação de azôto e potássio Fertilizer experiments with cotton: IV- Experiments on the time of application of nitrogen and potassium

    Directory of Open Access Journals (Sweden)

    O. S. Neves

    1957-01-01

    Full Text Available Neste artigo os autores relatam os resultados obtidos em 10 ensaios, instalados em sete diferentes localidades e abrangendo os principais tipos de solo do Estado de São Paulo. Esses ensaios foram realizados entre 1949-50 e 1953-54 e, excetuando-se um, foram conduzidos por dois ou três anos nos mesmos canteiros, fornecendo, ao todo, 22 resultados anuais. O objetivo em mira foi estudar a melhor época para a aplicação do azôto e do potássio, sendo estes nutrientes, assim como o fósforo, empregados sozinhos ou em diversas combinações. O azôto foi usado na forma de salitre do Chile e, conforme o ensaio, nas doses de 20 ou 30 kg/ha de N; o fósforo como superfosfato, na dose de 60 kg/ha de P2O5; o potássio como cloreto, nas doses de 30 ou 40 kg/ha de K2O. Em média dos ensaios, o efeito do azôto aplicado em cobertura 30-40 dias após a emergência das plantas foi muito superior ao do empregado por ocasião do plantio, nos sulcos destinados às sementes, sendo também maior que o da aplicação em cobertura feita 60-80 dias após a emergência. O fracionamento da dose de azôto em duas porções iguais - estudado em quatro ensaios, compreendendo oito resultados anuais - mostrou-se ainda superior à aplicação da dose total 30-40 dias após a emergência. Quando as duas porções- foram aplicadas em cobertura o efeito do azôto foi bem maior que nas combinações de épocas em que uma das porções foi empregada por ocasião do plantio. Um exame retrospectivo, baseado nos presentes ensaios e nos relatados em artigo anterior, perfazendo 30 resultados anuais, confirmou integralmente as conclusões acima, mostrando que é inútil tentar-se avaliar o efeito dos adubos azotados solúveis empregando-os nos sulcos de plantio, conforme o hábito arraigado em nosso meio, e que a aplicação em cobertura, pouco antes ou logo que aparecerem no algodoal os primeiros botões florais, geralmente dá bons resultados. Nos ensaios em que se p

  5. Prediction of corrosion rate of AZ31B magnesium alloy under salt fog environment in NaCl solution

    OpenAIRE

    even">D.Thirumalaikumarasamy,; , K.Shanmugam and V. Balasubramanian

    2013-01-01

    Magnesium alloys have gained considerable interest as a material for automotive and aerospace applications due to its low density, high specific strength, and good castability. However, another considerable issue is their corrosion properties. This restricts their practical applications. In this present research, corrosion behavior of the AZ31B magnesium alloy was evaluated by conducting salt fog test in NaCl solution at different chloride ion concentrations, pH values, spraying times, and ai...

  6. Nucleons in nuclei, however

    International Nuclear Information System (INIS)

    The topics presented at the 1989 Joliot-Curie Lectures are reported. Two main subjects were retained: a simplified description of the N-body motion of particles in the quasi-particle configuration; study of the dynamics of nuclear components which are not described by nucleons in their ground state. The following themes were presented: quasiparticles and the Green functions, relativistic aspects of the quasiparticle concept, the dimensions of nucleons in the nuclei and the EMC effect, quarks and gluons in the nuclei, the delta in the nuclei, the strangeness, quasiparticles far from the Fermi sea, diffusion of electrons, stellar evolution and nucleosynthesis

  7. From Nucleons To Nuclei To Fusion Reactions

    Energy Technology Data Exchange (ETDEWEB)

    Quaglioni, S; Navratil, P; Roth, R; Horiuchi, W

    2012-02-15

    Nuclei are prototypes of many-body open quantum systems. Complex aggregates of protons and neutrons that interact through forces arising from quantum chromo-dynamics, nuclei exhibit both bound and unbound states, which can be strongly coupled. In this respect, one of the major challenges for computational nuclear physics, is to provide a unified description of structural and reaction properties of nuclei that is based on the fundamental underlying physics: the constituent nucleons and the realistic interactions among them. This requires a combination of innovative theoretical approaches and high-performance computing. In this contribution, we present one of such promising techniques, the ab initio no-core shell model/resonating-group method, and discuss applications to light nuclei scattering and fusion reactions that power stars and Earth-base fusion facilities.

  8. Brueckner-AMD study of light nuclei

    International Nuclear Information System (INIS)

    In many states of light nuclei, the cluster structure is observed in addition to the shell structure. To understand the mechanism of clustering, we apply the Brueckner theory to the Antisymmetrized Molecular Dynamics (AMD) based on realistic nuclear interactions. The Bethe-Goldstone equation in the Brueckner theory is solved for every nucleon pair described by wave packets of AMD, and the G-matrix is calculated with single-particle orbits in AMD self-consistently. We show applicability of this method not only to self-conjugate nuclei but also to N ≠ Z nuclei with A ≤ 12. It is confirmed that these results present reasonable description of cluster structures and energy-level schemes in comparison with the experimental ones in light nuclei. For 8Be having a typical α + α cluster structure, the structure dependence of the G-matrix is investigated and the role of tensor force is shown to be important in understanding the clustering mechanism.

  9. Study of nuclear level densities for exotic nuclei

    Directory of Open Access Journals (Sweden)

    M Nasri Nasrabadi

    2012-06-01

    Full Text Available Nuclear level density (NLD is one of the properties of nuclei with widespread applications in astrophysics and nuclear medicine. Since there has been little experimental and theoretical research on the study of nuclei which are far from stability line, studying NLD for these nuclei is of crucial importance. Also, as NLD is an important input for nuclear research codes, hence studying the methods for calculation of this parameter is essential. Besides introducing various methods and models for calculating NLD for practical applications, we used exact spectra distribution (SPDM for determining NLD of two neutron and proton enriched exotic nuclei with the same mass number.

  10. Coulomb energy of nuclei

    International Nuclear Information System (INIS)

    The density functional determining the Coulomb energy of nuclei is calculated to the first order in e2. It is shown that the Coulomb energy includes three terms: the Hartree energy; the Fock energy; and the correlation Coulomb energy (CCE), which contributes considerably to the surface energy, the mass difference between mirror nuclei, and the single-particle spectrum. A CCE-based mechanism of a systematic shift of the single-particle spectrum is proposed. A dominant contribution to the CCE is shown to come from the surface region of nuclei. The CCE effect on the calculated proton drip line is examined, and the maximum charge Z of nuclei near this line is found to decrease by 2 or 3 units. The effect of Coulomb interaction on the effective proton mass is analyzed

  11. Coulomb Energy of Nuclei

    CERN Document Server

    Shaginyan, V R

    2001-01-01

    The density functional determining the Coulomb energy of nuclei is calculated to the first order in $e^2$. It is shown that the Coulomb energy includes three terms: the Hartree energy; the Fock energy; and the correlation Coulomb energy (CCE), which contributes considerably to the surface energy, the mass difference between mirror nuclei, and the single-particle spectrum. A CCE-based mechanism of a systematic shift of the single-particle spectrum is proposed. A dominant contribution to the CCE is shown to come from the surface region of nuclei. The CCE effect on the calculated proton drip line is examined, and the maximum charge $Z$ of nuclei near this line is found to decrease by 2 or 3 units. The effect of Coulomb interaction on the effective proton mass is analyzed.

  12. Coulomb Energy of Nuclei

    OpenAIRE

    Shaginyan, V. R.

    2002-01-01

    The density functional determining the Coulomb energy of nuclei is calculated to the first order in $e^2$. It is shown that the Coulomb energy includes three terms: the Hartree energy; the Fock energy; and the correlation Coulomb energy (CCE), which contributes considerably to the surface energy, the mass difference between mirror nuclei, and the single-particle spectrum. A CCE-based mechanism of a systematic shift of the single-particle spectrum is proposed. A dominant contribution to the CC...

  13. Hot nuclei and fragmentation

    International Nuclear Information System (INIS)

    A review is made of the present status concerning the production of nuclei above 5 MeV temperature. Considerable progress has been made recently on the understanding of the formation and the fate of such hot nuclei. It appears that the nucleus seems more stable against temperature than predicted by static calculations. However, the occurrence of multifragment production at high excitation energies is now well established. The various experimental features of the fragmentation process are discussed. (author) 59 refs., 12 figs

  14. Electroweak interactions in nuclei

    Science.gov (United States)

    Henley, E. M.

    1984-06-01

    Nuclear and subnuclear degrees of freedom and lepton nucleus scattering were discussed. Electroweak interactions in nuclei were examined. Topics discussed include: introduction to electroweak theory; the Weinberg-Salam theory for leptons; the Weinberg-Salam theory for hadrons-the GIM mechanism; electron scattering as a probe of the electroweak interaction (observation of PV, the weak interaction for nucleons, and parity violation in atoms); and time reversed invariance and electric dipole moments of nucleons, nuclei, and atoms.

  15. Fabrication of microfluidic chips using lithographic patterning and adhesive bonding of the thick negative photoresist AZ 125 nXT

    Science.gov (United States)

    Knoll, Thorsten; Bergmann, Andreas; Nußbaum, Dominic

    2015-05-01

    In this work, for the first time the negative photoresist AZ 125 nXT was used for the fabrication of a microfluidic chip. Usually, fabrication of microfluidic devices on the basis of silicon or glass substrates is done by using the epoxy-based negative photoresist SU-8 or other thick film polymer materials. The suitability of SU-8 for various microfluidic applications has been shown in the fields of bioanalytic devices, lab-on-chip systems or microreaction technology. However, processing is always a very challenging task with regard to the adaptation of process parameters to the individual design and required functionality. Now, the AZ 125 nXT allows for the fabrication of structures in a wide thickness range with only one type of viscosity. In contrast to SU-8, the AZ 125 nXT is fully cross-linked during UV exposure and does not require a time-consuming post-exposure bake. 90 μm deep microfluidic channels were defined by lithographic patterning of AZ 125 nXT. Sealing of the open microfluidic channels was performed by a manual adhesive bonding process at a temperature of 100 °C. The fluidic function was successfully tested with flow rates up to 20 ml/min by means of a microfluidic edge connector. Long term stability and chemical resistance of the fabricated microfluidic channels will be investigated in the near future. The presented work shows the potential of AZ 125 nXT as a possible alternative to SU-8 for the fabrication of microfluidic chips.

  16. Permutation group in light nuclei

    International Nuclear Information System (INIS)

    From general features of the multiplet scheme, a framework is provided for the application of permutation groups to the structure of light nuclei. It is shown that the description of nuclear states in terms of cluster configurations offers possibilities of finding the best orbital states for a given partition f. The significance of the orbital partition for orbital states is explained in terms of selection rules. Specific methods and results obtained in shell configurations, cluster configurations, and nuclear reactions are discussed. (2 figures, 4 tables, 42 references) (U.S.)

  17. High energy neutron cross-sections and kerma values of biomedical interest calculated with a nuclear model applicable to light nuclei

    International Nuclear Information System (INIS)

    A model has been developed for calculating fast neutron cross sections (E > 14 MeV) for light nuclei of biomedical interest. The model explicitly includes experimental nuclear structure information. Some calculations for 12C, 14N, and 16O are presented

  18. LASER CLADDING OF MAGNESIUM ALLOY AZ91D WITH SILICON CARBIDE

    OpenAIRE

    L. F. CAI; C. K. MARK; WEI ZHOU

    2009-01-01

    Mg alloys are ultralight but their structural applications are often limited by their poor wear and corrosion resistance. The research aimed to address the problem by laser-cladding. Cladding with SiC powder onto surface of AZ91D was carried out using Nd:YAG laser. The laser-clad surface was analyzed using the optical microscope, SEM equipped with EDS, and XRD and found to contain SiC and other Si compounds such as Mg2Si and Al3.21Si0.47 as well as much refined α-Mg grains and β-Mg17Al12 inte...

  19. On the cold rolling of AZ31 Mg alloy after Equal Channel Angular Pressing

    Directory of Open Access Journals (Sweden)

    Seyed Mohammad Arab

    2014-09-01

    Full Text Available Among the various Severe Plastic Deformation (SPD processes, Equal Channel Angular Pressing (ECAP is one of the most applicable one which improves strength and ductility due to grain refinement and suitable texture development. In this study, cold rolling were carried out on the 4 pass ECAPed (in route A and C strip shaped specimens of AZ31 magnesium alloy to investigate the ECAP effects on the roll-ability. Results showed that reduction in area which can be concerned as an index for roll-ability increased after ECAP. It was also seen that ECAP in route C enhanced roll-ability more than route A.

  20. On the cold rolling of AZ31 Mg alloy after Equal Channel Angular Pressing

    OpenAIRE

    Seyed Mohammad Arab; Abbas Akbarzadeh

    2014-01-01

    Among the various Severe Plastic Deformation (SPD) processes, Equal Channel Angular Pressing (ECAP) is one of the most applicable one which improves strength and ductility due to grain refinement and suitable texture development. In this study, cold rolling were carried out on the 4 pass ECAPed (in route A and C) strip shaped specimens of AZ31 magnesium alloy to investigate the ECAP effects on the roll-ability. Results showed that reduction in area which can be concerned as an index for roll-...

  1. MICROSTRUCTURE AND MECHANICAL PROPERTIES OF AZ91D EXTRUDED TUBE

    Institute of Scientific and Technical Information of China (English)

    B.Y. Yu; C.L. Bao; H.W. Song; Z. Liu; H.P. Yu

    2006-01-01

    The effect of extrusion ratio on microstructures and mechanical properties of magnesium alloy AZ91D extruded tube at 430℃ has been studied. After the evolution of microstructure and mechanical properties of AZ91D during extrusion were studied, the following parameters were obtained: tensile strength reached the climax value of 306.9MPa and elongation peak value of10.1% at an extrusion ratio of 7.125, and with the increase of the extrusion ratio to 7.45, yield strength reached a top value of 285.795MPa with decreased tensile strength and elongation. It was concluded that mechanical properties of magnesium alloys AZ91D could be enhanced by adjusting the extrusion ratio near recrystallization.

  2. Preliminary study of biodegradation of AZ31B magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    REN Yibin; HUANG Jingjing; ZHANG Bingchun; YANG Ke

    2007-01-01

    Magnesium alloys are potential to be developed as a new type of biodegradable implant material by use of their active corrosion behavior.Both in vitro and in vivo biodegradation properties of an AZ31B magnesium alloy were investigated in this work.The results showed that AZ31B alloy has a proper degradation rate and much lower hydrogen release in Hank's solution,with a degradation rate of about 0.3 mm/year and hydrogen release below 0.15mL/cm2.The animal implantation test showed that the AZ31B alloy could slowly biodegrade in femur of the rabbit and form calcium phosphate around the alloy sample,with the Ca/P ratio close to the natural bone.

  3. The evolutionary differentiation of two histone H2A.Z variants in chordates (H2A.Z-1 and H2A.Z-2) is mediated by a stepwise mutation process that affects three amino acid residues

    OpenAIRE

    Ausió Juan; Ishibashi Toyotaka; Dryhurst Deanna; González-Romero Rodrigo; Eirín-López José M

    2009-01-01

    Abstract Background The histone H2A family encompasses the greatest number of core histone variants of which the replacement variant H2A.Z is currently one of the most heavily studied. No clear mechanism for the functional variability that H2A.Z imparts to chromatin has yet been proposed. While most of the past studies have referred to H2A.Z generically as a single protein, in vertebrates it is a mixture of two protein forms H2A.Z-1 (previously H2A.Z) and H2A.Z-2 (previously H2A.F/Z or H2A.V)...

  4. Enhancing Microstructure and Mechanical Properties of AZ31-MWCNT Nanocomposites through Mechanical Alloying

    OpenAIRE

    B.K.Raghunath; Rao, T H; Jayakumar, J.

    2013-01-01

    Multiwall carbon nanotubes (MWCNTs) reinforced Mg alloy AZ31 nanocomposites were fabricated by mechanical alloying and powder metallurgy technique. The reinforcement material MWCNTs were blended in three weight fractions (0.33%, 0.66%, and 1%) with the matrix material AZ31 (Al-3%, zinc-1% rest Mg) and blended through mechanical alloying using a high energy planetary ball mill. Specimens of monolithic AZ31 and AZ31-MWCNT composites were fabricated through powder metallurgy technique. The micro...

  5. Physics of Unstable Nuclei

    Science.gov (United States)

    Khoa, Dao Tien; Egelhof, Peter; Gales, Sydney; Giai, Nguyen Van; Motobayashi, Tohru

    2008-04-01

    Studies at the RIKEN RI beam factory / T. Motobayashi -- Dilute nuclear states / M. Freer -- Studies of exotic systems using transfer reactions at GANIL / D. Beaumel et al. -- First results from the Magnex large-acceptance spectrometer / A. Cunsolo et al. -- The ICHOR project and spin-isospin physics with unstable beams / H. Sakai -- Structure and low-lying states of the [symbol]He exotic nucleus via direct reactions on proton / V. Lapoux et al. -- Shell gap below [symbol]Sn based on the excited states in [symbol]Cd and [symbol]In / M. Górska -- Heavy neutron-rich nuclei produced in the fragmentation of a [symbol]Pb beam / Zs. Podolyák et al. -- Breakup and incomplete fusion in reactions of weakly-bound nuclei / D.J. Hinde et al. -- Excited states of [symbol]B and [symbol]He and their cluster aspect / Y. Kanada-En'yo et al. -- Nuclear reactions with weakly-bound systems: the treatment of the continuum / C. H. Dasso, A. Vitturi -- Dynamic evolution of three-body decaying resonances / A. S. Jensen et al. -- Prerainbow oscillations in [symbol]He scattering from the Hoyle state of [symbol]C and alpha particle condensation / S. Ohkubo, Y. Hirabayashi -- Angular dispersion behavior in heavy ion elastic scattering / Q. Wang et al. -- Microscopic optical potential in relativistic approach / Z.Yu. Ma et al. -- Exotic nuclei studied in direct reactions at low momentum transfer - recent results and future perspectives at fair / P. Egelhof -- Isotopic temperatures and symmetry energy in spectator fragmentation / M. De Napoli et al. -- Multi-channel algebraic scattering theory and the structure of exotic compound nuclei / K. Amos et al. -- Results for the first feasibility study for the EXL project at the experimental storage ring at GSI / N. Kalantar-Nayestanaki et al. -- Coulomb excitation of ISOLDE neutron-rich beams along the Z = 28 chain / P. Van Duppen -- The gamma decay of the pygmy resonance far from stability and the GDR at finite temperature / G. Benzoni et al

  6. AZ-101 Mixer Pump Test Qualification Test Procedures (QTP)

    International Nuclear Information System (INIS)

    Describes the Qualification test procedure for the AZ-101 Mixer Pump Data Acquisition System (DAS). The purpose of this Qualification Test Procedure (QTP) is to confirm that the AZ-101 Mixer Pump System has been properly programmed and hardware configured correctly. This QTP will test the software setpoints for the alarms and also check the wiring configuration from the SIMcart to the HMI. An Acceptance Test Procedure (ATP), similar to this QTP will be performed to test field devices and connections from the field

  7. Thermal analytical investigations of the magnesium alloy AZ91

    Directory of Open Access Journals (Sweden)

    K.N. Braszczyńska - Malik

    2007-04-01

    Full Text Available The results of thermal derivative analysis (TDA, differential scanning calorimetric (DSC measurements and microstructure investigations of commercial AZ91 magnesium alloy are presented. The performed examinations allowed to determine the microstructure after solidification process and also precipitation process during continuous heating of supersaturated solid solution. The α-phase and α+γ semi-divorced eutectic were observed in as-cast material, whereas both discontinuous and continuous precipitates of γ phase were revealed after heating supersaturated AZ91 alloy.

  8. Corrosion performance of atmospheric plasma sprayed alumina coatings on AZ31B magnesium alloy under immersion environment

    OpenAIRE

    D. Thirumalaikumarasamy; K. Shanmugam; Balasubramanian, V

    2014-01-01

    Plasma sprayed ceramic coatings are successfully used in many industrial applications, where high wear and corrosion resistance with thermal insulation are required. The alumina powders were plasma sprayed on AZ31B magnesium alloy with three different plasma spraying parameters. In the present work, the influence of plasma spray parameters on the corrosion behavior of the coatings was investigated. The corrosion behavior of the coated samples was evaluated by immersion corrosion test in 3.5 w...

  9. Research on the drawing process with a large total deformation wires of AZ31 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Bajor, T; Muskalski, Z; Suliga, M, E-mail: tbajor@wip.pcz.p [Czestochowa University of Technology, Faculty of Materials Processing Technology and Applied Physics, Al. Armii Krajowej 19, 42-200 Czestochowa (Poland)

    2010-07-01

    Magnesium and their alloys have been extensively studied in recent years, not only because of their potential applications as light-weight engineering materials, but also owing to their biodegradability. Due to their hexagonal close-packed crystallographic structure, cold plastic processing of magnesium alloys is difficult. The preliminary researches carried out by the authors have indicated that the application of the KOBO method, based on the effect of cyclic strain path change, for the deformation of magnesium alloys, provides the possibility of obtaining a fine-grained structure material to be used for further cold plastic processing with large total deformation. The main purpose of this work is to present research findings concerning a detailed analysis of mechanical properties and changes occurring in the structure of AZ31 alloy wire during the multistage cold drawing process. The appropriate selection of drawing parameters and the application of multistep heat treatment operations enable the deformation of the AZ31 alloy in the cold drawing process with a total draft of about 90%.

  10. The evolutionary differentiation of two histone H2A.Z variants in chordates (H2A.Z-1 and H2A.Z-2 is mediated by a stepwise mutation process that affects three amino acid residues

    Directory of Open Access Journals (Sweden)

    Ausió Juan

    2009-02-01

    Full Text Available Abstract Background The histone H2A family encompasses the greatest number of core histone variants of which the replacement variant H2A.Z is currently one of the most heavily studied. No clear mechanism for the functional variability that H2A.Z imparts to chromatin has yet been proposed. While most of the past studies have referred to H2A.Z generically as a single protein, in vertebrates it is a mixture of two protein forms H2A.Z-1 (previously H2A.Z and H2A.Z-2 (previously H2A.F/Z or H2A.V that differ by three amino acids. Results We have performed an extensive study on the long-term evolution of H2A.Z across metazoans with special emphasis on the possible selective mechanisms responsible for the differentiation between H2A.Z-1 and H2A.Z-2. Our results reveal a common origin of both forms early in chordate evolution. The evolutionary process responsible for the differentiation involves refined stepwise mutation change within the codons of the three differential residues. This eventually led to differences in the intensity of the selective constraints acting upon the different H2A.Z forms in vertebrates. Conclusion The results presented in this work definitively reveal that the existence of H2A.Z-1 and H2A.Z-2 is not a whim of random genetic drift. Our analyses demonstrate that H2A.Z-2 is not only subject to a strong purifying selection but it is significantly more evolutionarily constrained than H2A.Z-1. Whether or not the evolutionary drift between H2A.Z-1 and H2A.Z-2 has resulted in a functional diversification of these proteins awaits further research. Nevertheless, the present work suggests that in the process of their differently constrained evolutionary pathways, these two forms may have acquired new or complementary functions.

  11. Particles and nuclei, letters

    International Nuclear Information System (INIS)

    The present collection of letters from JINR, Dubna, contains seven separate records on kinematic separation and mass analysis of heavy recoiling nuclei, dynamical effects prior to heavy ion fusion, VACTIV-DELPHI graphical dialog based program for the analysis of gamma-ray spectra, irradiation of nuclear emulsions in relativistic beams of 6He and3H nuclei, optical and structural investigations of PLZT x/65/35 (x = 4, 8 %) ferroelectric ceramics irradiated by a high-current pulsed electron beam, the oscillating charge and first evidence for neutrinoless double beta decay

  12. Particles and nuclei, letters

    International Nuclear Information System (INIS)

    The present collection of letters from JINR, Dubna, contains seven separate records on physics from extra dimensions, new physics in the new millennium with GENIUS: double beta decay, dark matter, solar neutrinos, the (μ-, e+) conversion in nuclei mediated by light Majorana neutrinos, exotic muon-to-positron conversion in nuclei: partial transition sum evaluation by using shell model, solar neutrino problem accounting for self consistent magnetohydrodynamics solution for solar magnetic fields, first neutrino observations from the Sudbury neutrino observatory and status report on BOREXINO and results of the muon-background measurements at CERN

  13. Rotational motion in nuclei

    International Nuclear Information System (INIS)

    Nuclear structure theories are reviewed concerned with nuclei rotational motion. The development of the deformed nucleus model facilitated a discovery of rotational spectra of nuclei. Comprehensive verification of the rotational scheme and a successful classification of corresponding spectra stimulated investigations of the rotational movement dynamics. Values of nuclear moments of inertia proved to fall between two marginal values corresponding to rotation of a solid and hydrodynamic pattern of an unrotating flow, respectively. The discovery of governing role of the deformation and a degree of a symmetry violence for determining rotational degrees of freedon is pointed out to pave the way for generalization of the rotational spectra

  14. Influence of shot peening on corrosion properties of biocompatible magnesium alloy AZ31 coated by dicalcium phosphate dihydrate (DCPD).

    Science.gov (United States)

    Mhaede, Mansour; Pastorek, Filip; Hadzima, Branislav

    2014-06-01

    Magnesium alloys are promising materials for biomedical applications because of many outstanding properties like biodegradation, bioactivity and their specific density and Young's modulus are closer to bone than the commonly used metallic implant materials. Unfortunately their fatigue properties and low corrosion resistance negatively influenced their application possibilities in the field of biomedicine. These problems could be diminished through appropriate surface treatments. This study evaluates the influence of a surface pre-treatment by shot peening and shot peening+coating on the corrosion properties of magnesium alloy AZ31. The dicalcium phosphate dihydrate coating (DCPD) was electrochemically deposited in a solution containing 0.1M Ca(NO3)2, 0.06M NH4H2PO4 and 10mL/L of H2O2. The effect of shot peening on the surface properties of magnesium alloy was evaluated by microhardness and surface roughness measurements. The influence of the shot peening and dicalcium phosphate dihydrate layer on the electrochemical characteristics of AZ31 magnesium alloy was evaluated by potentiodynamic measurements and electrochemical impedance spectroscopy in 0.9% NaCl solution at a temperature of 22±1°C. The obtained results were analyzed by the Tafel-extrapolation method and equivalent circuit method. The results showed that the application of shot peening process followed by DCPD coating improves the properties of the AZ31 surface from corrosion and mechanical point of view. PMID:24863232

  15. Radiometric assay for phenylethanolamine N-methyltransferase and catechol O-methyltransferase in a single tissue sample: application to rat hypothalamic nuclei, pineal gland, and heart

    International Nuclear Information System (INIS)

    A simple and highly sensitive method for simultaneous assay of phenylethanolamine N-methyltransferase (PNMT) and catechol O-methyltransferase (COMT) is described. These enzymes are determined in a single tissue homogenate using S-[methyl-3H] adenosyl-L-methionine as methyl donor and sequentially incubating with the substrates phenylethanolamine and epinephrine. The radioactive products of the enzymatic reactions, N-methylphenylethanolamine and metanephrine, are extracted and then separated by thin-layer chromatography. The identity of the reaction products has been established chromatographically and the conditions for both enzymatic reactions in the assay procedure have been defined. Measurement of PNMT activity in the rat pineal gland or in minute fragments of other tissues (e.g., brain nuclei) has not been possible using previously described methods. Activities of PNMT and COMT in the rat pineal gland, various hypothalamic nuclei, and the auricular and ventricular myocardia are herein reported

  16. Improvement on the quality of the images obtained with adaptive optics and application to the study of the active galactic nuclei

    OpenAIRE

    Exposito, Jonathan

    2013-01-01

    My work is connecting three areas in astrophysics: the study of active galactic nuclei (AGN), adaptive optics (AO) and the optimization of the methods for related data-processing. It focuses on the development of tools to obtain the best image quality in terms of resolution and contrast so as to maximize the scientific return especially for the study of AGN. Adaptive optics can compensate for the effects of atmospheric turbulence on the wavefront and thus to approach the theoretical resolutio...

  17. Three-cluster variant of the algebraic version of resonating group method and its application to the bound state properties study of 6He and 8He nuclei

    International Nuclear Information System (INIS)

    Microscopic model for three-cluster configuration of light nuclei has been formulated in the frameworks of resonating group method in its algebraic version. The model has been applied for the ground states of 6He and 8He in configuration of α-particle plus two n-clusters and α-particle plus two 2n-clusters. The results have been obtained emphasize the importance of three-cluster moving mode for adequate description of nuclear properties, especially neutron halo

  18. Neutron Halo Isomers in Stable Nuclei and their Possible Application for the Production of Low Energy, Pulsed, Polarized Neutron Beams of High Intensity and High Brilliance

    CERN Document Server

    Habs, D; Thirolf, P G; Böni, P

    2010-01-01

    We propose to search for neutron halo isomers populated via $\\gamma$-capture in stable nuclei with mass numbers of about A=140-180 or A=40-60, where the $4s_{1/2}$ or $3s_{1/2}$ neutron shell model state reaches zero binding energy. These halo nuclei can be produced for the first time with new $\\gamma$-beams of high intensity and small band width ($\\le$ 0.1\\%) achievable via Compton back-scattering off brilliant electron beams thus offering a promising perspective to selectively populate these isomers with small separation energies of 1 eV to a few keV. Similar to single-neutron halo states for very light, extremely neutron-rich, radioactive nuclei \\cite{hansen95,tanihata96,aumann00}, the low neutron separation energy and short-range nuclear force allows the neutron to tunnel far out into free space much beyond the nuclear core radius. This results in prolonged half lives of the isomers for the $\\gamma$-decay back to the ground state in the 100 ps-$\\mu$s range. Similar to the treatment of photodisintegration ...

  19. 78 FR 3877 - Radio Broadcasting Services; Peach Springs, AZ

    Science.gov (United States)

    2013-01-17

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Peach Springs, AZ AGENCY: Federal Communications... the Hualapai Tribe, proposing to amend the Table of Allotments by allotting Channel 265A at Peach... second potential service at Peach Springs. Channel 265A can be allotted at Peach Springs, Arizona,...

  20. 75 FR 76293 - Radio Broadcasting Services; Peach Springs, AZ

    Science.gov (United States)

    2010-12-08

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Peach Springs, AZ AGENCY: Federal Communications..., allots FM Channel 281C3 at Peach Springs, Arizona, in order to maintain a first local service at that community. Channel 281C3 can be allotted at Peach Springs, Arizona, in compliance with the...

  1. Mixer pump test plan for double shell tank AZ-101

    International Nuclear Information System (INIS)

    Mixer pump systems have been chosen as the method for retrieval of tank wastes contained in double shell tanks at Hanford. This document describes the plan for testing and demonstrating the ability of two 300 hp mixer pumps to mobilize waste in tank AZ-101. The mixer pumps, equipment and instrumentation to monitor the test were installed by Project W-151

  2. AZ91C magnesium alloy modified by Cd

    DEFF Research Database (Denmark)

    Shabadi, R.; Ambat, Rajan; Dwarakadasa, E.S.

    2014-01-01

    In the present work, the effect of Cd on the microstructure, mechanical properties and general corrosion behaviour of AZ91C alloys was investigated. Addition of Cd was found not to be efficient in modifying/refining the microstructure or β-phase. A morphology change in β-phase from fine continuou...

  3. Purification technology of AZ91 magnesium alloy wastes

    Institute of Scientific and Technical Information of China (English)

    吴国华; 谢敏; 翟春泉; 曾小勤; 朱燕萍; 丁文江

    2003-01-01

    The effects of different purification processes on the mechanical properties,structure and fracture pattern of AZ91 magnesium alloy wastes were studied.The results show that the inclusions in the Mg melt can be removed effectively by the treatment of the fluxes with MgO foam ceramic filter.Therefore,the properties of magnesium alloy wastes can be improved substantially.Tensile strength and elongation of the magnesium alloy wastes after purification treatment can reach 194.6 MPa and 5.12% respectively,which are comparable to the mechanical properties of AZ91 fresh stuff.The metallographic analysis results show that the purification treatment has not obvious effect on metallurgical structure.The fracture mechanism of AZ91 is not changed,and its fractures are still quasicleavage crack.It is discovered that for AZ91 magnesium alloy,the fluxes containing TiO2 can decrease the Fe content of magnesium alloy wastes to below 0.0056%.The results also show that TiO2 is helpful for the precipitation of γ phase in granular or small island shape and can refine the grain size effectively.

  4. User Manual for the AZ-101 Data Acquisition System (AS-101 DAS)

    Energy Technology Data Exchange (ETDEWEB)

    BRAYTON, D.D.

    2000-02-17

    User manual for the TK AZ-101 Waste Retrieval System Data Acquisition System. The purpose of this document is to describe use of the AZ-101 Data Acquisition System (AZ-101 DAS). The AZ-101 DAS is provided to fulfill the requirements for data collection and monitoring as defined in Letters of Instruction (LOI) from Numatec Hanford Corporation (NHC) to Fluor Federal Services (FFS). For a complete description of the system, including design, please refer to the AZ-101 DAS System Description document, RPP-5572.

  5. User Manual for the AZ-101 Data Acquisition System (AS-101 DAS)

    International Nuclear Information System (INIS)

    User manual for the TK AZ-101 Waste Retrieval System Data Acquisition System. The purpose of this document is to describe use of the AZ-101 Data Acquisition System (AZ-101 DAS). The AZ-101 DAS is provided to fulfill the requirements for data collection and monitoring as defined in Letters of Instruction (LOI) from Numatec Hanford Corporation (NHC) to Fluor Federal Services (FFS). For a complete description of the system, including design, please refer to the AZ-101 DAS System Description document, RPP-5572

  6. Interactions on Nuclei

    OpenAIRE

    Hoyer, Paul

    1995-01-01

    I review hard photon initiated processes on nuclei. The space-time development of the DIS reaction as viewed in the target rest frame qualitatively describes the nuclear shadowing of quark and gluon distributions, although it may be difficult to understand the very weak $Q^2$ dependence of the low $x$ data. The current jet hadron energy distribution at large $\

  7. Electroweak interactions in nuclei

    International Nuclear Information System (INIS)

    Topics include: introduction to electroweak theory; the Weinberg-Salam theory for leptons; the Weinberg-Salam theory for hadrons-the GIM mechanism; electron scattering as a probe of the electroweak interaction (observation of PV, the weak interaction for nucleons, and parity violation in atoms); and time reversed invariance and electric dipole moments of nucleons, nuclei, and atoms. 52 references

  8. Nuclei with tetrahedral symmetry

    International Nuclear Information System (INIS)

    We discuss a point-group-theory based method of searching for new regions of nuclear stability. We illustrate the related strategy with realistic calculations employing the tetrahedral and the octahedral point groups. In particular, several nuclei in the rare earth region appear as excellent candidates to study the new mechanism. (author)

  9. Octupole collectivity in nuclei

    Science.gov (United States)

    Butler, P. A.

    2016-07-01

    The experimental and theoretical evidence for octupole collectivity in nuclei is reviewed. Recent theoretical advances, covering a wide spectrum from mean-field theory to algebraic and cluster approaches, are discussed. The status of experimental data on the behaviour of energy levels and electric dipole and electric octupole transition moments is reviewed. Finally, an outlook is given on future prospects for this field.

  10. Triaxiality in superheavy nuclei

    International Nuclear Information System (INIS)

    In this work, triaxial degree of freedom is explicitly utilized in calculating alpha decay lifetimes. The synthesis of superheavy nuclei with Z = 114-116 and 118 were detected by their decaying alpha chains with terminating spontaneous fission events. The lifetime of alpha decay chains measured are to be compared with the values evaluated theoretically

  11. Fissibility of compound nuclei

    CERN Document Server

    Iwata, Yoritaka

    2012-01-01

    Collisions between $^{248}$Cm and $^{48}$Ca are systematically investigated by time-dependent density functional calculations with evaporation prescription. Depending on the incident energy and impact parameter, fusion, deep-inelastic and fission events are expected to appear. In this paper, a microscopic method of calculating the fissibility of compound nuclei is presented.

  12. Quick Surface Treatment of AZ31B by AC Micro-arc Oxidation

    Institute of Scientific and Technical Information of China (English)

    WANG Shenglin; ZHANG Peng; DU Yunhui; WANG Yujie; HAO Zhiqiang

    2014-01-01

    In order to explore an effective way to shorten treatment time and enhance the quality of treatment coating, AC micro-arc oxidation was conducted to treat the surface of AZ31B deformation magnesium alloy in KF+KOH treatment solution. The influences of micro-arc oxidation parameters such as concentration of KF, concentration of KOH, output voltage of booster, temperature of treatment solution, and treatment time on treatment coating thickness were raveled out under different conditions. The structure and composition of treatment coating were determined, the growth mechanism of treatment coating was discussed, and the quick surface treatment technology for compact treatment coating with maximum thickness was developed. The experimental results show that:A maximum 33μm-thick compact treatment coating, consisting of MgF2 and MgO mainly, can be formed on AZ31B in 112s under the conditions of 1 132 g/L KF, 382 g/L KOH, 66 V for output voltage of booster and 34℃of treatment solution which were optimized by a genetic algorithm from the model established by artificial neural networks. There are no“crater-shaped”pores in this treatment coating as the heat shock resulting from the smooth variation of AC sinusoidal voltage is far smaller than that of the rigidly varied DC or pulse current. The treatment time is only one sixth of that adopted in the other surface treatment technology at best, principally for the reason that the coating can always grow irrespective of the electric potential of AZ31B. This investigation lays a firm foundation for the extensive application of magnesium alloy.

  13. Computer Model Of Fragmentation Of Atomic Nuclei

    Science.gov (United States)

    Wilson, John W.; Townsend, Lawrence W.; Tripathi, Ram K.; Norbury, John W.; KHAN FERDOUS; Badavi, Francis F.

    1995-01-01

    High Charge and Energy Semiempirical Nuclear Fragmentation Model (HZEFRG1) computer program developed to be computationally efficient, user-friendly, physics-based program for generating data bases on fragmentation of atomic nuclei. Data bases generated used in calculations pertaining to such radiation-transport applications as shielding against radiation in outer space, radiation dosimetry in outer space, cancer therapy in laboratories with beams of heavy ions, and simulation studies for designing detectors for experiments in nuclear physics. Provides cross sections for production of individual elements and isotopes in breakups of high-energy heavy ions by combined nuclear and Coulomb fields of interacting nuclei. Written in ANSI FORTRAN 77.

  14. Medium energy hadron scattering from nuclei

    International Nuclear Information System (INIS)

    The Glauber approximation for medium energy scattering of hadronic projectiles from nuclei is combined with the interacting boson model of nuclei to produce a transition matrix for elastic and inelastic scattering in algebraic form which includes coupling to all the intermediate states. We present closed form analytic expresions for the transition matrix elements for the three dynamical symmetries of the interacting boson model; that is for, a spherical quadrupole vibrator, a γ unstable rotor, and both prolate and oblate axially symmetric rotors. We give examples of application of this formalism to proton scattering from 154Sm and 154Gd. 27 refs., 5 figs., 1 tab

  15. Corrosion Resistance of AZ91 Magnesium Alloy with Pulse Electrodeposited Ni-SiC Nanocomposite Coating

    Directory of Open Access Journals (Sweden)

    A. Amadeh

    2012-03-01

    Full Text Available Magnesium and its alloys are the lightest of the structural metals, which makes them one of the most promising materials to minimize vehicle weight, but poor surface properties restrict the application of these alloys. In this paper, Ni-SiC nanocomposite coatings were applied on AZ91 magnesium alloy from Watts bath containing different amounts of SiC content by pulse electrodeposition technique. The morphology and phase analysis were carried out by Scanning Electron Microscopy (SEM and X-Ray Diffraction (XRD analysis, respectively. Microhardness of specimens was measured and the results revealed a significant enhancement from 74 H for bare AZ91 magnesium alloy to 523 HV for the specimen coated in the bath containing 15 g.L–1 SiC. The Corrosion behavior of the samples was studied by potentiodaynamic polarization, and the obtained data showed superior corrosion resistance for coated AZ91 magnesium alloy, i.e. the corrosion current density decreased from 2.69 mA.cm–2, for the uncoated sample, to 0.00046 mA.cm–2, for coated specimen in the bath containing 15 g.L–1 SiC and the corrosion potential increased from – 2.069 V to – 0.33 V at the same conditions. Magnesium and its alloys are the lightest of the structural metals, which makes them one of the most promising materials to minimize vehicle weight, but poor surface properties restrict the application of these alloys. In this paper, Ni-SiC nanocomposite coatings were applied on AZ91 magnesium alloy from Watts bath containing different amounts of SiC content by pulse electrodeposition technique. The morphology and phase analysis were carried out by Scanning Electron Microscopy (SEM and X-Ray Diffraction (XRD analysis, respectively. Microhardness of specimens was measured and the results revealed a significant enhancement from 74 H for bare AZ91 magnesium alloy to 523 HV for the specimen coated in the bath containing 15 g.L–1 SiC. The Corrosion behavior of the samples was studied by

  16. Flow Stress and Mathematical Model for DRX Evolution of Semi-continuous Cast AZ80 Alloy During Hot Deformation

    Directory of Open Access Journals (Sweden)

    Liang Haicheng

    2016-01-01

    Full Text Available Using electromagnetic fields application ways, AZ80 magnesium alloy is semi-continuously cast into billets with diameter of 165 mm. And the dynamic recrystallization (DRX evolution of the semi-continuous cast AZ80 magnesium alloy during hot compression has been experimentally studied on Gleeble 2000 thermal-mechanical simulator, at temperatures from 260 to 410 °C and strain rates from 0.001 to 10s-1. It is found that the chief microstructure evolution is dynamic recrystallization, and the effect of deformation process parameters on DRX evolution is analyzed. The mathematical models including critical recrystallization model, kinetics model and grain size model of DRX are established and the results show good agreement between experiments and the models.

  17. Triaxiality in 146,148Sm nuclei

    International Nuclear Information System (INIS)

    Recently, attempts have been made to use the dynamic pairing plus quadrupole model to evaluate B(E2) values, B(E2) branching ratios, and low-lying energy levels for 146,148Sm nuclei, which are in poor agreement with experiment. Application of the boson expansion technique on 148Sm shows too much splitting and an incorrect order for the quintet states, while other properties have not been discussed. In the present work, 146,148Sm nuclei have been described using an asymmetric rotor model framework. The nonaxiality parameter γ has been evaluated using the energy ration E2+'/E6+. Remarkable success has been achieved in explaining the correct ordering of known low-lying energy levels, B(E2) values, and B(E2) branching ratios, which indicate that the so-called spherical nuclei may be treated as triaxial. (author). 8 refs., 9 tabs., 1 fig

  18. Fast neutron inelastic scattering from nuclei

    International Nuclear Information System (INIS)

    The need for accurate values of inelastic scattering cross sections appears when the requests for neutron data for reactors and other applied purposes are considered. These requests are partly related to values for spherical nuclei, well studied over many years. These studies were extensively considered in two review papers presented, in 1976, at the International Conference on the Interactions of Neutrons with nuclei. Other requests are related to vibrational and rotational nuclei, and relevant studies have been recently performed. The quality of these investigations and the large number of recent results have lead to concentration on them as the topic of the present review. The constant improvements of the experimental techniques permits precise measurements of inelastic scattering cross sections to the first excited levels over a range of incident energies, such that different reactions mechanisms are predominant in different parts of that range of energies. Quadrupole, hexadecapole and octupole deformation parameters of the target nuclei can be deduced from the data using phenomenological models. The successful application of the analysis over the range of energies leads to the conclusion that reliable information on the shape of the nuclei has been derived. The validity of the various models, which include direct interaction and compound nucleus reaction mechanisms, is discussed in connection with analyses of recent experiments. (author)

  19. Grain refinement of AZ91D alloy by intensive melt shearing and its persistence after remelting and isothermal holding

    Directory of Open Access Journals (Sweden)

    Zuo Yubo

    2013-01-01

    Full Text Available Intensive melt shearing has a significant grain refining effect on some light alloys. However, the persistence of the grain refining effect during isothermal holding and remelting is still unclear, although it is very important for the practical application. In this study, intensive melt shearing was achieved in a twin-screw mechanism to investigate its grain refining effect on AZ91D magnesium alloy. The refinement mechanism was discussed and the persistence of grain refinement after remelting and isothermal holding was also studied. A Zeiss imaging system with polarized light was used for quantitative measurement of grain size. The results show that the intensive melt shearing has a significant grain refining effect on AZ91D magnesium alloy. With the application of intensive melt shearing, the grain size of AZ91D magnesium alloy can be reduced from 530 μm (for a typical as-cast microstructure to 170 μm, which is about 70% size reduction. The grain refinement achieved by the intensive melt shearing can be partially kept after isothermal holding and remelting. It is believed that the refinement effect was mainly due to the finer and well dispersed oxide particles formed by high intensive shearing. The smaller size of oxide particles and their slow motion velocity in the sheared melt could make important contributions to the remained grain refinement.

  20. Effect of rolling temperature of the magnesium alloy AZ31B formability; Efeito da temperatura de laminacao na deformabilidade da liga de magnesio AZ31B

    Energy Technology Data Exchange (ETDEWEB)

    Catorceno, L.L.C.; Zimmermann, A.J.O.; Padilha, A.F., E-mail: litzy.catorceno@poli.usp.b [Universidade de Sao Paulo (DEMM/EP/USP), SP (Brazil). Escola Politecnica. Dept. de Engenharia Metalurgica e de Materiais

    2010-07-01

    The magnesium alloy AZ31B presents an interesting set of properties, which makes it potential candidate for applications in automotive and aeronautics. The main limitation of magnesium alloys is the low capacity of plastic forming at room temperature. The main motivation of this project is to understand and control the microstructure and crystallographic texture of magnesium alloys, to improve their formability. The effect of rolling temperature on the formability of the alloy was studied in this stage of the project. The alloy in the form of annealed and recrystallized sheets (2 mm thick) was deformed by rolling at four different temperatures: 25, 100, 200 and 250 deg C. The microstructural characterization was achieved using several complementary techniques of microstructural analysis, such as optical microscopy, scanning electron microscopy, X-ray analysis by energy dispersive, X-ray diffraction and microhardness. Results about the effect of rolling temperature on the alloy formability were presented and discussed. (author)

  1. Cytotoxicity studies of AZ31D alloy and the effects of carbon dioxide on its biodegradation behavior in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jiali, E-mail: wangjialicsu@yahoo.cn [Center for Translational Medicine Research and Development, Institute of Biomedical and Health Engineering, Chinese Academy of Sciences, Shenzhen 518055 (China); Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong SAR (China); Qin, Ling [Center for Translational Medicine Research and Development, Institute of Biomedical and Health Engineering, Chinese Academy of Sciences, Shenzhen 518055 (China); Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong SAR (China); Wang, Kai [School of Humanities and Social Sciences, Hunan University of Chinese Medicine, Changsha 410208 (China); Wang, Jue; Yue, Ye [Center for Translational Medicine Research and Development, Institute of Biomedical and Health Engineering, Chinese Academy of Sciences, Shenzhen 518055 (China); Li, Yangde [Guangdong Innovation Team for Biodegradable Magnesium and Medical Implants, E-ande, Dongguan 523660 (China); Tang, Jian [Center for Translational Medicine Research and Development, Institute of Biomedical and Health Engineering, Chinese Academy of Sciences, Shenzhen 518055 (China); Li, Weirong [Guangdong Innovation Team for Biodegradable Magnesium and Medical Implants, E-ande, Dongguan 523660 (China)

    2013-10-01

    Magnesium alloys have been advocated as potential artificial bone materials due to their biocompatibility and biodegradability. The understanding of their corrosive mechanism in physiological environments is therefore essential for making application-orientated designs. Thus, this in vitro study was designed to assess the effects of CO{sub 2} on corrosive behavior of AZ31D to mimic in vivo special ingredient. Electrochemical technologies accompanied with Scanning electron microscope, Fourier transform infrared, X-ray diffraction, Energy dispersive spectroscopy and hydrogen evolution measurement were employed to analyze corrosive rates and mechanisms of AZ31D. Moreover, the biocompatibility of AZ31D was assessed with a direct cell attachment assay and an indirect cytotoxicity test in different diluted extracts. The ion concentrations in extracts were measured using inductively coupled plasma mass spectrometry to offer explanations on the differences of cell viability in the indirect test. The results of the direct cytotoxicity assay showed that the corrosive rate of AZ31D was too rapid to allow for cell adhesion. Extracts diluted less than 20 times would cause adverse effects on cell proliferation, likely due to excessive ions and gas release. Moreover, the presence of CO{sub 2} did not cause significant differences on corrosive behavior of AZ31D according to the results of electrochemical testing and hydrogen evolution measurement. This might be caused by the simultaneous process of precipitation and dissolution of MgCO{sub 3} due to the penetration role of CO{sub 2}. This analysis of corrosive atmospheres on the degradation behavior of magnesium alloys would contribute to the design of more scientific in vitro testing systems in the future. - Highlights: • We evaluate the effects of CO{sub 2} on corrosion behavior of magnesium alloys. • We assess the feasibility of commercial AZ31D alloy as potential implants. • CO{sub 2} is not the key factor to minimize

  2. Pairing correlations in exotic nuclei

    CERN Document Server

    Sagawa, H

    2012-01-01

    The BCS and HFB theories which can accommodate the pairing correlations in the ground states of atomic nuclei are presented. As an application of the pairing theories, we investigate the spatial extension of weakly bound Ne and C isotopes by taking into account the pairing correlation with the Hartree-Fock-Bogoliubov (HFB) method and a 3-body model, respectively. We show that the odd-even staggering in the reaction cross sections of $^{30,31,32}$Ne and $^{14,15,16}$C are successfully reproduced, and thus the staggering can be attributed to the unique role of pairing correlations in nuclei far from the stability line. A correlation between a one-neutron separation energy and the anti-halo effect is demonstrated for $s$- and p-waves using the HFB wave functions. We also propose effective density-dependent pairing interactions which reproduce both the neutron-neutron ($nn$) scattering length at zero density and the neutron pairing gap in uniform matter. Then, we apply these interactions to study pairing gaps in ...

  3. The expressions for the super-allowed beta-decay rates in the Coriolis coupling model: application to the 1d5/2 shell nuclei

    International Nuclear Information System (INIS)

    The expressions for super-allowed beta-decay transition rates have been derived within the context of the Coriolis coupling model. The derived expressions, valid for the beta-decay between any two mirror nuclei, have been applied to calculate super-allowed beta-decay transition rates of 21Na, 23Mg, 25Al, and 27Si. Without the use of any hindrance factor, the calculated rates agree well with the data and also with the calculations done using the shell model with configuration admixture. (author)

  4. Disintegration of comet nuclei

    International Nuclear Information System (INIS)

    The breaking up of comets into separate pieces, each with its own tail, was seen many times by astronomers of the past. The phenomenon was in sharp contrast to the idea of the eternal and unchangeable celestial firmament and was commonly believed to be an omen of impending disaster, especially for comets with tails stretching across half the sky. It is only now that we have efficient enough space exploration tools to see comet nuclei and even - in the particular case of small comet Hartley-2 in 2010 - to watch their disintegration stage. There are also other suspected candidates for disintegration in the vast family of comet nuclei and other Solar System bodies. (physics of our days)

  5. Bubble nuclei; Noyaux Bulles

    Energy Technology Data Exchange (ETDEWEB)

    Legoll, F. [Service de Physique Theorique, CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)

    1998-07-22

    For nuclei with very high electrical charge, the Coulomb field is expected to drive the protons away from the centre to the surface of the nucleus. Such a nucleus would be no more compact but look like a bubble. The goal of this work is to confirm this idea. We are interested in only the ground state of spherical nuclei. We use the Skyrme potential with the Sly4 parametrization to calculate the mean-field Hamiltonian. Paring correlations are described by a surface-active delta paring interaction. In its ground state the nucleus {sup A=900} X{sub Z=274} is shown to be a bubble. Another stable state is found with a little higher energy: it is also a bubble. (author) 11 refs., 18 figs., 33 tabs.

  6. Nuclei in the Cosmos

    International Nuclear Information System (INIS)

    Nuclei in the Cosmos is the foremost bi-annual conference of nuclear physicists, astrophysicists, cosmochemists, and others to survey the recent achievements in Nuclear Astrophysics. As an interdisciplinary meeting it promotes mutual understanding and collaboration over fields fundamental to solve a range of open questions, from the origin of the elements to stellar evolution. Inherent part of the conference is a school devoted to students and young scientists where prominent scientists introduce the field of nuclear astrophysics to the participants. Conference Topics: Cosmology and big bang nucleosynthesis; Element production, stellar evolution and stellar explosions; Evidences of nucleosynthesis in stars and in presolar grains; Experiments in nuclear astrophysics; Nuclei far from stability; Nuclear theory in astrophysics; New facilities. [TRA

  7. Photoabsorption in nuclei

    OpenAIRE

    Effenberger, M.; Mosel, U.

    1997-01-01

    We calculate the total photoabsorption cross section and cross sections for inclusive pion and eta photoproduction in nuclei in the energy range from 300 MeV to 1 GeV within the framework of a semi-classical BUU transport model. Besides medium modifications like Fermi motion and Pauli blocking we focus on the collision broadening of the involved resonances. The resonance contributions to the elementary cross section are fixed by fits to partial wave amplitudes of pion photoproduction. The cro...

  8. Gluon density in nuclei

    OpenAIRE

    Ayala, A. L.; Ducati, M. B. Gay; Levin, E. M.

    1996-01-01

    In this talk we present our detail study ( theory and numbers) [1] on the shadowing corrections to the gluon structure functions for nuclei. Starting from rather contraversial information on the nucleon structure function which is originated by the recent HERA data, we develop the Glauber approach for the gluon density in a nucleus based on Mueller formula [2] and estimate the value of the shadowing corrections in this case. Than we calculate the first corrections to the Glauber approach and ...

  9. Resistance spot welding of AZ series magnesium alloys: Effects of aluminum content on microstructure and mechanical properties

    International Nuclear Information System (INIS)

    The microstructural evolution of the spot welded AZ31, AZ61 and AZ80 magnesium alloys was studied via optical and scanning electron microscopy. As the Al content of the magnesium base alloy increased from 3 wt% (AZ31) to 6% (AZ61) and 8% (AZ80), columnar to equi-axed dendrite transition and grain refinement in the fusion zone were enhanced. However, the increasing amount of the β-Mg17(Al,Zn)12 phase in the heat affected zone (HAZ) and fusion zone (FZ) resulted in the reduction of the tensile shear strengths of the AZ61 and AZ80 welds compared to those of AZ31 welds. Moreover, in the tensile-shear testing, the AZ61 and AZ80 welds failed in the heat affected zone along the fusion boundary, because micro-cracking occurred preferentially at the interfaces between β particles and Mg matrix. Post-weld solutionizing treatment was found to significantly reduce the quantity of β particles in heat affected and fusion zones of AZ61 and AZ80 welds. This led to an increase in the weld strengths of AZ61 and AZ80 alloys because the heat treatment eliminated the β particles and cracks propagated into the coarse-grained heat affected zone and then base material. For the heat treated welds, grain size was found as a major factor in the failure mode

  10. Resistance spot welding of AZ series magnesium alloys: Effects of aluminum content on microstructure and mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Niknejad, Seyedtirdad, E-mail: snikneja@uwaterloo.ca [Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave., Waterloo, Ontario, Canada N2l 3G1 (Canada); Liu, Lei [Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Lee, Mok-Young [Research Institute of Industrial Science and Technology, Pohang 790-600 (Korea, Republic of); Esmaeili, Shahrzad; Zhou, Norman Y. [Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave., Waterloo, Ontario, Canada N2l 3G1 (Canada)

    2014-11-17

    The microstructural evolution of the spot welded AZ31, AZ61 and AZ80 magnesium alloys was studied via optical and scanning electron microscopy. As the Al content of the magnesium base alloy increased from 3 wt% (AZ31) to 6% (AZ61) and 8% (AZ80), columnar to equi-axed dendrite transition and grain refinement in the fusion zone were enhanced. However, the increasing amount of the β-Mg{sub 17}(Al,Zn){sub 12} phase in the heat affected zone (HAZ) and fusion zone (FZ) resulted in the reduction of the tensile shear strengths of the AZ61 and AZ80 welds compared to those of AZ31 welds. Moreover, in the tensile-shear testing, the AZ61 and AZ80 welds failed in the heat affected zone along the fusion boundary, because micro-cracking occurred preferentially at the interfaces between β particles and Mg matrix. Post-weld solutionizing treatment was found to significantly reduce the quantity of β particles in heat affected and fusion zones of AZ61 and AZ80 welds. This led to an increase in the weld strengths of AZ61 and AZ80 alloys because the heat treatment eliminated the β particles and cracks propagated into the coarse-grained heat affected zone and then base material. For the heat treated welds, grain size was found as a major factor in the failure mode.

  11. Structures of exotic nuclei

    International Nuclear Information System (INIS)

    Discoveries of many different types of nuclear shape coexistence are being found at both low and high excitation energies throughout the periodic table, as documented in recent reviews. Many new types of shape coexistence have been observed at low excitation energies, for examples bands on more than four different overlapping and coexisting shapes are observed in 185Au, and competing triaxial and prolate shapes in 71Se and 176Pt. Discrete states in super-deformed bands with deformations β 2 ∼ 0.4-0.6, coexisting with other shapes, have been seen to high spin up to 60ℎ in 152Dy, 132Ce and 135Nd. Super-deformed nuclei with N and Z both around 38 and around Z = 38, N ≥ 60. These data led to the discovery of new shell gaps and magic numbers of 38 for N and Z and 60 for N but now for deformed shapes. Marked differences in structure are observed at spins of 6 to 20 in nuclei in this region, which differ by only two protons; for example, 68Ge and 70Se. The differences are thought to be related to the competing shell gaps in these nuclei

  12. On Quasibound N* Nuclei

    CERN Document Server

    Kelkar, N G; Moskal, P

    2015-01-01

    The possibility for the existence of unstable bound states of the S11 nucleon resonance N$^*$(1535) and nuclei is investigated. These quasibound states are speculated to be closely related to the existence of the quasibound states of the eta mesons and nuclei. Within a simple model for the N N$^*$ interaction involving a pion and eta meson exchange, N$^*$-nucleus potentials for N*-$^3$He and N*-$^{24}$Mg are evaluated and found to be of a Woods-Saxon like form which supports two to three bound states. In case of N*-$^3$He, one state bound by only a few keV and another by 4 MeV is found. The results are however quite sensitive to the N N$^*$ $\\pi$ and N N$^*$ $\\eta$ vertex parameters. A rough estimate of the width of these states, based on the mean free path of the exchanged mesons in the nuclei leads to very broad states with $\\Gamma \\sim$ 80 and 110 MeV for N*-$^3$He and N*-$^{24}$Mg respectively.

  13. The surface chemistry of 3-mercaptopropyltrimethoxysilane films deposited on magnesium alloy AZ91

    International Nuclear Information System (INIS)

    Magnesium and its alloys have desirable physical and mechanical properties for a number of applications. Unfortunately, these materials are highly susceptible to corrosion, particularly in the presence of aqueous solutions. The purpose of this study is to develop a uniform, non-toxic surface treatment to enhance the corrosion resistance of magnesium alloys. This paper reports the influence of the coating bath parameters and alloy microstructure on the deposition of 3-mercaptopropyltrimethoxysilane (MPTS) coatings on magnesium alloy AZ91. The surface chemistry at the magnesium/MPTS interface has also been explored. The results indicate that the deposition of MPTS onto AZ91 was influenced by both the pH and MPTS concentration in the coating bath. Furthermore, scanning electron microscopy results showed that the MPTS film deposited uniformly on all phases of the magnesium alloy surface. X-ray photoelectron spectroscopy studies revealed that at the magnesium/MPTS interface, the molecules bond to the surface through the thiol group in an acid-base interaction with the Mg(OH)2 layer, whereas in the bulk of the film, the molecules are randomly oriented.

  14. Laser Methods in the Study of Nuclei, Atoms and Molecules

    Science.gov (United States)

    Inamura, Takashi T.

    2005-01-01

    The VIth International Workshop on Application of Lasers in Atomic Nuclei Research was held at Adam Mickiewicz University, Poznan in Poland from May 24 to 27, 2004. Its title this year was "Laser methods in the study of nuclei, atoms and molecules". Some topics are reviewed from a viewpoint of the atomic physics contribution to nuclear physics and its applications. It is suggested how this meeting should be organized in the future by taking the new geopolitics into account.

  15. BASEMAP, LA PAZ COUNTY, AZ, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — FEMA Framework Basemap datasets comprise six of the seven FGDC themes of geospatial data that are used by most GIS applications (Note: the seventh framework theme,...

  16. Constitutive turnover of histone H2A.Z at yeast promoters requires the preinitiation complex

    Science.gov (United States)

    Tramantano, Michael; Sun, Lu; Au, Christy; Labuz, Daniel; Liu, Zhimin; Chou, Mindy; Shen, Chen; Luk, Ed

    2016-01-01

    The assembly of the preinitiation complex (PIC) occurs upstream of the +1 nucleosome which, in yeast, obstructs the transcription start site and is frequently assembled with the histone variant H2A.Z. To understand the contribution of the transcription machinery in the disassembly of the +1 H2A.Z nucleosome, conditional mutants were used to block PIC assembly. A quantitative ChIP-seq approach, which allows detection of global occupancy change, was employed to measure H2A.Z occupancy. Blocking PIC assembly resulted in promoter-specific H2A.Z accumulation, indicating that the PIC is required to evict H2A.Z. By contrast, H2A.Z eviction was unaffected upon depletion of INO80, a remodeler previously reported to displace nucleosomal H2A.Z. Robust PIC-dependent H2A.Z eviction was observed at active and infrequently transcribed genes, indicating that constitutive H2A.Z turnover is a general phenomenon. Finally, sites with strong H2A.Z turnover precisely mark transcript starts, providing a new metric for identifying cryptic and alternative sites of initiation. DOI: http://dx.doi.org/10.7554/eLife.14243.001 PMID:27438412

  17. Superplastic Properties of AZ31 and AZ31-1.0Y-1.3Sr Alloy Produced by Twin-Roll Casting and Sequential Hot Rolling

    Science.gov (United States)

    Ning, Huiyan; Yu, Yandong; Lin, Kai; Wen, Lihua; Liu, Chunxiang

    2016-02-01

    Superplastic mechanical properties of the AZ31 and AZ31-1.0Y-1.3Sr magnesium alloy sheets produced by twin-roll casting and sequential hot rolling (TRC) were investigated. The AZ31-1.0Y-1.3Sr alloy sheets with the thickness of 1 mm were prepared by twin-roll casting process, which exhibited finer equiaxed grain structure. Uniaxial tensile testing and gas blow forming on AZ31 and AZ31-1.0Y-1.3Sr magnesium alloy sheets were carried out. Results show that the superplastic mechanical properties of AZ31-1.0Y-1.3Sr alloys are better than those of AZ31 alloys at 400 °C and the strain rate of 7 × 10-4/s. The addition of Y and Sr elements is helpful to improve the formability of AZ31 alloy. Grain boundary sliding plays a dominant role in superplastic forming.

  18. Laser Cladding of Magnesium Alloy AZ91D with Silicon Carbide

    Science.gov (United States)

    Cai, L. F.; Mark, C. K.; Zhou, Wei

    Mg alloys are ultralight but their structural applications are often limited by their poor wear and corrosion resistance. The research aimed to address the problem by laser-cladding. Cladding with SiC powder onto surface of AZ91D was carried out using Nd:YAG laser. The laser-clad surface was analyzed using the optical microscope, SEM equipped with EDS, and XRD and found to contain SiC and other Si compounds such as Mg2Si and Al3.21Si0.47 as well as much refined α-Mg grains and β-Mg17Al12 intermetallics. The laser-clad surface possesses considerably higher hardness but its corrosion resistance is not improved, indicating that the laser-cladding technique can only be adopted for applications in noncorrosive environments where wear is the predominant problem.

  19. In vitro and in vivo studies of biodegradable fine grained AZ31 magnesium alloy produced by equal channel angular pressing.

    Science.gov (United States)

    Ratna Sunil, B; Sampath Kumar, T S; Chakkingal, Uday; Nandakumar, V; Doble, Mukesh; Devi Prasad, V; Raghunath, M

    2016-02-01

    The objective of the present work is to investigate the role of different grain sizes produced by equal channel angular pressing (ECAP) on the degradation behavior of magnesium alloy using in vitro and in vivo studies. Commercially available AZ31 magnesium alloy was selected and processed by ECAP at 300°C for up to four passes using route Bc. Grain refinement from a starting size of 46μm to a grain size distribution of 1-5μm was successfully achieved after the 4th pass. Wettability of ECAPed samples assessed by contact angle measurements was found to increase due to the fine grain structure. In vitro degradation and bioactivity of the samples studied by immersing in super saturated simulated body fluid (SBF 5×) showed rapid mineralization within 24h due to the increased wettability in fine grained AZ31 Mg alloy. Corrosion behavior of the samples assessed by weight loss and electrochemical tests conducted in SBF 5× clearly showed the prominent role of enhanced mineral deposition on ECAPed AZ31 Mg in controlling the abnormal degradation. Cytotoxicity studies by MTT colorimetric assay showed that all the samples are viable. Additionally, cell adhesion was excellent for ECAPed samples particularly for the 3rd and 4th pass samples. In vivo experiments conducted using New Zealand White rabbits clearly showed lower degradation rate for ECAPed sample compared with annealed AZ31 Mg alloy and all the samples showed biocompatibility and no health abnormalities were noticed in the animals after 60days of in vivo studies. These results suggest that the grain size plays an important role in degradation management of magnesium alloys and ECAP technique can be adopted to achieve fine grain structures for developing degradable magnesium alloys for biomedical applications. PMID:26652384

  20. The Formablity of AZ31B Magnesium Alloy Sheet

    Institute of Scientific and Technical Information of China (English)

    WANG Lingyun; LU Zhiwen; ZHAO Yazhong; QIU Xiaogang

    2006-01-01

    The forming limit diagrams(FLD)of AZ31B magnesium alloy sheet were tested by means of the electro etching grid method based on the forming experiment of magnesium alloy sheet carried out with a BCS-30D sheet forming testing machine and the strain testing analysis made with an advanced ASAME automatic strain measuring system. Experiments show that, at room temperature, the mechanical properties and deep drawing performance of AZ31B cold-rolled magnesium alloy sheet were so poor that it failed to test the forming limit diagrams without an ideal forming and processing capacity, while the hot-rolled magnesium alloy sheet was of a little better plasticity and forming performance after testing its forming limit diagrams. It can be concluded that the testing of the forming limit curves (FLC)offers the theoretical foundation for the drawing of the deep drawing and forming process of magnesium alloy sheet.

  1. Perturbative many-body approaches to finite nuclei

    International Nuclear Information System (INIS)

    In this work the authors discuss various approaches to the effective interaction appropriate for finite nuclei. The methods reviewed are the folded-diagram method of Kuo and co-workers and the summation of the folded diagrams as advocated by Lee and Suzuki. Examples of applications to sd-shell nuclei from previous works are discussed together with hitherto unpublished results for nuclei in pf-shell. Since the method of Lee and Suzuki is found to yield the best converged results, this method is applied to calculate the effective interaction for nuclei in the pf-shell. For the calculation of the effective interaction, three recent versions of the Bonn meson-exchange potential model have been used. These versions are fitted to the same set of data and differ only in the strength of the tensor force. The importance of the latter for finite nuclei is discussed. 67 refs., 17 figs., 7 tabs

  2. Inverter DC resistance spot welding of magnesium alloy AZ31

    OpenAIRE

    Hwang, I. S.; D. C. Kim; Kang, M. J.

    2011-01-01

    Purpose: The welding lobes of AC resistance spot welding and inverter DC resistance spot welding for the magnesium alloy sheet AZ31 were compared and analyzed.Design/methodology/approach: Using the welding lobe in terms of electrode force, weld time, and weld current which are process variables of the resistance spot welding, optimal welding conditions were determined. The lower limit of the range of the optimal welding condition was decided by minimum shear tension strength for the magnesium...

  3. Self-assembled monolayers formed on AZ31 Mg alloy

    Science.gov (United States)

    Salman, S. A.; Okido, M.

    2012-07-01

    Self-assembled monolayer (SAM) was successfully adsorbed on the AZ31 Mg alloy surface using oleic acid and stearic acid with various organic solvents, such as acetone, ethanol, and hexane. The surface monolayers were characterized using contact angle measurements, X-ray photoelectron spectroscopy (XPS) and anodic polarization test. It was shown that the higher contact angle and the best anti-corrosion property were obtained with treatment in oleic acid with ethanol solution.

  4. ADATBIZTONSÁG AZ RFID ALKALMAZÁSAKOR

    OpenAIRE

    Radványi, Tibor

    2013-01-01

    Ebben a cikkben az RFID (Rádiófrekvenciás azonosítás) technológia használata által felvetett adatbiztonsági kérdések kerülnek megtárgyalásra. Milyen támadási lehetőségek vannak, és milyen védekezési lépéseket tehetünk ezek kivédésére. Egy termék számtalan veszélynek van kitéve, ameddig a gyártótól el nem jut a fogyasztóhoz. Ez elég hosszú folyamat, amely során az áruk elveszhetnek, vagy ellophatják őket. Az EU előírások a legtöbb árucikk esetében egyre messzebb tolják ki a gyártói felelőssége...

  5. Forging and Rolling of magnesium alloy AZ61

    Directory of Open Access Journals (Sweden)

    M. Greger

    2007-01-01

    Full Text Available Purpose: The paper summarises results of experiments aimed at development of structure of modified alloyAZ61 at hot deformation.Design/methodology/approach: Deformation behaviour of alloy was verified at the temperature of 420°C byrolling at 380°C by forging, respectively.Findings: Magnesium alloy AZ 61 have hexagonal structure and their forming is at room temperatures verydifficult, that’s why big plastic deformations are carried out in hot condition. After plastic deformations wasobtained that original grain size decreased 15 times.Research limitations/implications: This paper provide data about magnitude of deformation, strain rate andtemperature of forming at different techniques of plastic deformation. It was aimed to determine the conditionsfor non problem rolling and forging respectively.Practical implications: Initial structure was as cast and after heat treatment T4. Heat treatment appeared muchbetter for forming as well as forging than rolling because of state of stress.Originality/value: Role of βphase (Mg17Al12 in these alloys at plastic forming is very important, such thathow it was obtained, best final properties of AZ 61 alloy supports very fine particles, distributed into Mg matrix.Next a relevant information is that multi stage forming process is much better in comparison with a big singlereduction.

  6. Rheological Behavior of Semi-Solid AZ91D Alloy

    Institute of Scientific and Technical Information of China (English)

    Weimin MAO; Zisheng ZHEN; Shijian YAN; Xueyou ZHONG

    2004-01-01

    The rheological behavior and microstructure of semi-solid AZ91D was studied using a Couette type viscometer. The results show that the apparent viscosity of semi-solid AZ91D increases with the cooling rate increasing when it is continuously cooled and mechanically stirred and the empiric relation of the apparent viscosity with the cooling rate and solid fraction at shearing rate 93.7 s-1 is expressed as η=[0.66 - 0.63e(-ε/3.01)]e(fs/0.14), and with the shearing rate and solid fraction at cooling rate 4℃/min is shown as η=0.55e(fs/0.11-γ/87.59), as well as the cooling rate and shearing rate have an important effect on the microstructure of the semi-solid AZ91D alloy slurry, and decreasing the cooling rate and increasing the shearing rate are favorable to the nondendritic evolution of the primary grains.

  7. Microstructures of AZ91D alloy solidified during electromagnetic stirring

    Institute of Scientific and Technical Information of China (English)

    MAO Wei-min; ZHEN Zi-sheng; CHEN Hong-tao

    2005-01-01

    With the help of an electromagnetic stirring device self-made and alloy melt quenching technology,the effect of electromagnetic stirring parameters on the microstructures of semi-solid AZ91D alloy was mainly studied at the stirring frequency of 200 Hz.The experimental results show that when the stirring power rises,the primary α-Mg rosettes in the semi-solid melt will bear stronger man-made temperature fluctuation and the root remelting effect of the dendritic arms is promoted so that the spherical primary α-Mg grains become much more and rounder.If the stirring frequency is 200 Hz,the ideal semi-solid microstructure of AZ91D magnesium alloy can be obtained when the stirring power is increased to 6.0 kW.If the stirring frequency is 200 Hz and the stirring power is 6.0 kW,it is found that the lower cooling rate is favorable for the spherical primary α-Mg grains to be developed during the electromagnetic stirring stage.If the AZ91D magnesium alloy billet prepared during electromagnetic stirring at the stirring frequency of 200 Hz and the stirring power of 6.0 kW is reheated to the solidus and liquidus temperature region,the primary α-Mg grain's shape will get more spherical,so it is very advantageous to the semi-solid thixoforming process.

  8. Determination of the excitation energy and angular momentum of high spin formed nuclei with Diamant and Eurogam II: application to the study of 84Zr deexcitation

    International Nuclear Information System (INIS)

    The association of the Diamant multi-detector of light particles and of the Eurogam II gamma radiation multi-detector has permitted to determine the excitation energy and angular momentum of high spin formed nuclei. In a first step, the gamma radiation response of this set of detectors has been simulated precisely using the Geant 3 Monte Carlo code. This simulation has been validated by a detailed comparison of the data characterizing Eurogam II (efficiency, peak/total ratio). This simulation has permitted to extract for the first time the multiplicity response of Eurogam II with respect to the measured gamma fold, for the experimental conditions considered in this work. From this multiplicity, it is possible to evaluate the spin of the residual nuclei formed. The measurement with Diamant of the energy of each light particle evaporated during the fusion-evaporation reaction allows to reach the excitation energy of the residual nucleus formed. This approach has permitted to determine the experimental input line of the 84Zr residual nucleus formed during the 32S + 58Ni reaction at 120 and 130 MeV after emission of two protons with a single alpha. These results are compared to those of a statistical evaporation code. The superdeformed states of 84Zr have been occupied only at the 130 MeV bombardment energy. The low supply intensity of this structure shows an angular momentum effect. The study of the quasi-continuum of quadrupolar transitions occupied in 84Zr indicates a change of the nucleus structure: a crossing of orbitals involving the H11/2 orbital should explain the variations of the kinematic and dynamic inertia momentums observed in this region. (J.S.)

  9. Dynamic Chirality in Nuclei

    International Nuclear Information System (INIS)

    Chirality has recently been proposed as a novel feature of rotating nuclei [1]. Because the chiral symmetry is dichotomic, its spontaneous breaking by the axial angular momentum vector leads to doublets of closely lying rotational bands of the same parity. To investigate nuclear chirality, next to establish the existence of almost degenerate rotational bands, it is necessary to measure also other observables and compare them to the model predictions. The crucial test for the suggested nuclei as candidates to express chirality is based on precise lifetime measurements. Two lifetime experiments and theoretical approaches for the description of the experimental results will be presented. Lifetimes of exited states in 134Pr were measured [2,3] by means of the recoil distance Doppler-shift and Doppler-shift attenuation techniques. The branching ratios and the electric or magnetic character of the transitions were also investigated [3]. The experiments were performed at IReS, Strasbourg, using the EUROBALL IV spectrometer, in conjunction with the inner bismuth germanate ball and the Cologne coincidence plunger apparatus. Exited states in 134Pr were populated in the fusion-evaporation reaction 119Sn(19F, 4n)134Pr. The possible chiral interpretation of twin bands was investigated in the two-quasiparticle triaxial rotor [1] and interacting boson-fermion-fermion models [4]. Both theoretical approaches can describe the level-scheme of 134Pr. The analysis of the wave functions has shown that the possibility for the angular momenta of the proton, neutron, and core to find themselves in the favorable, almost orthogonal geometry, is present but is far from being dominant [3,5]. The structure is characterized by large β and γ fluctuations. The existence of doublets of bands in 134Pr can be attributed to weak chirality dominated by shape fluctuations. In a second experiment branching ratios and lifetimes in 136Pm were measured by means of the recoil distance Doppler-shift and

  10. Study of nuclei' excitation in the charge exchange reactions (Draft)

    International Nuclear Information System (INIS)

    Carried out experimental and theoretical studies show, that in the nuclear charge exchange reactions there is an unique ability for study both properties and behavior of the delta-isobar in the excited nuclear environment. However for theoretical analysis of these reactions it is necessary have experimental data on nuclei charge exchange on free nucleons. It is offered the experiment of measurement dependence of inclusive cross section of the tritium nuclei charge exchange in 3He nuclei on hydrogen from transferred energy. This reaction is isotopically dependent on 3He nuclei in tritons charge exchange reaction on neutrons. Aim of proposed experiment is checking of a hypothesis believability about the delta-isobar excitation in flying nucleus, and measurement of the process intensity. Peculiarity of this experiment is application of relativistic tritons beams formed from accelerated fragments of 4He nuclei. Experimental facility presents of combination of two one-arm spectrometers: first one - time-flying spectrometer for measurement tritium nuclei impulse in beam to target with accuracy 0.3 % for 6 GeV/s and identification of tritium nuclei, the second one - magnetic spectrometer for identification and measurement of 3He nuclei impulse forming in the result of the charge exchange reaction

  11. Reorganization of Damaged Chromatin by the Exchange of Histone Variant H2A.Z-2

    Energy Technology Data Exchange (ETDEWEB)

    Nishibuchi, Ikuno [Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima (Japan); Department of Radiation Oncology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima (Japan); Department of Radiation Oncology, Hiroshima Prefectural Hospital, Hiroshima (Japan); Suzuki, Hidekazu; Kinomura, Aiko; Sun, Jiying; Liu, Ning-Ang [Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima (Japan); Horikoshi, Yasunori [Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima (Japan); Research Center for Mathematics of Chromatin Live Dynamics, Hiroshima University, Hiroshima (Japan); Shima, Hiroki [Department of Biochemistry, Graduate School of Medical Sciences, Tohoku University, Sendai (Japan); Kusakabe, Masayuki; Harata, Masahiko [Laboratory of Molecular Biology, Graduate School of Agricultural Science, Tohoku University, Sendai (Japan); Fukagawa, Tatsuo [Department of Molecular Genetics, National Institute of Genetics and The Graduate University for Advanced Studies, Mishima (Japan); Ikura, Tsuyoshi [Laboratory of Chromatin Regulatory Network, Department of Mutagenesis, Radiation Biology Center, Kyoto University, Kyoto (Japan); Ishida, Takafumi [Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima (Japan); Nagata, Yasushi [Department of Radiation Oncology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima (Japan); Tashiro, Satoshi, E-mail: ktashiro@hiroshima-u.ac.jp [Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima (Japan); Research Center for Mathematics of Chromatin Live Dynamics, Hiroshima University, Hiroshima (Japan)

    2014-07-15

    Purpose: The reorganization of damaged chromatin plays an important role in the regulation of the DNA damage response. A recent study revealed the presence of 2 vertebrate H2A.Z isoforms, H2A.Z-1 and H2A.Z-2. However, the roles of the vertebrate H2A.Z isoforms are still unclear. Thus, in this study we examined the roles of the vertebrate H2A.Z isoforms in chromatin reorganization after the induction of DNA double-strand breaks (DSBs). Methods and Materials: To examine the dynamics of H2A.Z isoforms at damaged sites, we constructed GM0637 cells stably expressing each of the green fluorescent protein (GFP)-labeled H2A.Z isoforms, and performed fluorescence recovery after photobleaching (FRAP) analysis and inverted FRAP analysis in combination with microirradiation. Immunofluorescence staining using an anti-RAD51 antibody was performed to study the kinetics of RAD51 foci formation after 2-Gy irradiation of wild-type (WT), H2A.Z-1- and H2A.Z-2-deficient DT40 cells. Colony-forming assays were also performed to compare the survival rates of WT, H2A.Z-1-, and H2A.Z-2-deficient DT40 cells with control, and H2A.Z-1- and H2A.Z-2-depleted U2OS cells after irradiation. Results: FRAP analysis revealed that H2A.Z-2 was incorporated into damaged chromatin just after the induction of DSBs, whereas H2A.Z-1 remained essentially unchanged. Inverted FRAP analysis showed that H2A.Z-2 was released from damaged chromatin. These findings indicated that H2A.Z-2 was exchanged at DSB sites immediately after the induction of DSBs. RAD51 focus formation after ionizing irradiation was disturbed in H2A.Z-2-deficient DT40 cells but not in H2A.Z-1-deficient cells. The survival rate of H2A.Z-2-deficient cells after irradiation was lower than those of WT and H2A.Z-1- DT40 cells. Similar to DT40 cells, H2A.Z-2-depleted U2OS cells were also radiation-sensitive compared to control and H2A.Z-1-depleted cells. Conclusions: We found that vertebrate H2A.Z-2 is involved in the regulation of the DNA

  12. Reorganization of Damaged Chromatin by the Exchange of Histone Variant H2A.Z-2

    International Nuclear Information System (INIS)

    Purpose: The reorganization of damaged chromatin plays an important role in the regulation of the DNA damage response. A recent study revealed the presence of 2 vertebrate H2A.Z isoforms, H2A.Z-1 and H2A.Z-2. However, the roles of the vertebrate H2A.Z isoforms are still unclear. Thus, in this study we examined the roles of the vertebrate H2A.Z isoforms in chromatin reorganization after the induction of DNA double-strand breaks (DSBs). Methods and Materials: To examine the dynamics of H2A.Z isoforms at damaged sites, we constructed GM0637 cells stably expressing each of the green fluorescent protein (GFP)-labeled H2A.Z isoforms, and performed fluorescence recovery after photobleaching (FRAP) analysis and inverted FRAP analysis in combination with microirradiation. Immunofluorescence staining using an anti-RAD51 antibody was performed to study the kinetics of RAD51 foci formation after 2-Gy irradiation of wild-type (WT), H2A.Z-1- and H2A.Z-2-deficient DT40 cells. Colony-forming assays were also performed to compare the survival rates of WT, H2A.Z-1-, and H2A.Z-2-deficient DT40 cells with control, and H2A.Z-1- and H2A.Z-2-depleted U2OS cells after irradiation. Results: FRAP analysis revealed that H2A.Z-2 was incorporated into damaged chromatin just after the induction of DSBs, whereas H2A.Z-1 remained essentially unchanged. Inverted FRAP analysis showed that H2A.Z-2 was released from damaged chromatin. These findings indicated that H2A.Z-2 was exchanged at DSB sites immediately after the induction of DSBs. RAD51 focus formation after ionizing irradiation was disturbed in H2A.Z-2-deficient DT40 cells but not in H2A.Z-1-deficient cells. The survival rate of H2A.Z-2-deficient cells after irradiation was lower than those of WT and H2A.Z-1- DT40 cells. Similar to DT40 cells, H2A.Z-2-depleted U2OS cells were also radiation-sensitive compared to control and H2A.Z-1-depleted cells. Conclusions: We found that vertebrate H2A.Z-2 is involved in the regulation of the DNA

  13. Enhancing Microstructure and Mechanical Properties of AZ31-MWCNT Nanocomposites through Mechanical Alloying

    Directory of Open Access Journals (Sweden)

    J. Jayakumar

    2013-01-01

    Full Text Available Multiwall carbon nanotubes (MWCNTs reinforced Mg alloy AZ31 nanocomposites were fabricated by mechanical alloying and powder metallurgy technique. The reinforcement material MWCNTs were blended in three weight fractions (0.33%, 0.66%, and 1% with the matrix material AZ31 (Al-3%, zinc-1% rest Mg and blended through mechanical alloying using a high energy planetary ball mill. Specimens of monolithic AZ31 and AZ31-MWCNT composites were fabricated through powder metallurgy technique. The microstructure, density, hardness, porosity, ductility, and tensile properties of monolithic AZ31 and AZ31-MWCNT nano composites were characterized and compared. The characterization reveals significant reduction in CNT (carbon nanoTube agglomeration and enhancement in microstructure and mechanical properties due to mechanical alloying through ball milling.

  14. XPS study of the surface chemistry on AZ31 and AZ91 magnesium alloys in dilute NaCl solution

    Science.gov (United States)

    Wang, Lei; Shinohara, Tadashi; Zhang, Bo-Ping

    2010-08-01

    The surface chemistry on AZ31 and AZ91 magnesium alloys was characterized by X-ray photoelectron spectroscopy (XPS) in the corrosion and the passivation zones. In the corrosion zone, the presence of Mg(OH) 2 and MgCO 3 species was found in the outer surface, whereas, in the inner layer, the co-existence of Mg(OH) 2, MgO and MgCO 3 species was observed for both alloys. The presence of Al 3+ in the surface electrolyte to form Al 2O 3/Al(OH) 3 and the formation of carbonate product provide a better passivation on the surfaces and retard the chloride-induced corrosion on the materials in the passivation zone.

  15. XPS study of the surface chemistry on AZ31 and AZ91 magnesium alloys in dilute NaCl solution

    Energy Technology Data Exchange (ETDEWEB)

    Wang Lei [Materials Reliability Center, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047 (Japan); School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Shinohara, Tadashi, E-mail: SHINOHARA.Tadashi@nims.go.jp [Materials Reliability Center, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047 (Japan); Zhang Boping [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China)

    2010-08-01

    The surface chemistry on AZ31 and AZ91 magnesium alloys was characterized by X-ray photoelectron spectroscopy (XPS) in the corrosion and the passivation zones. In the corrosion zone, the presence of Mg(OH){sub 2} and MgCO{sub 3} species was found in the outer surface, whereas, in the inner layer, the co-existence of Mg(OH){sub 2}, MgO and MgCO{sub 3} species was observed for both alloys. The presence of Al{sup 3+} in the surface electrolyte to form Al{sub 2}O{sub 3}/Al(OH){sub 3} and the formation of carbonate product provide a better passivation on the surfaces and retard the chloride-induced corrosion on the materials in the passivation zone.

  16. XPS study of the surface chemistry on AZ31 and AZ91 magnesium alloys in dilute NaCl solution

    International Nuclear Information System (INIS)

    The surface chemistry on AZ31 and AZ91 magnesium alloys was characterized by X-ray photoelectron spectroscopy (XPS) in the corrosion and the passivation zones. In the corrosion zone, the presence of Mg(OH)2 and MgCO3 species was found in the outer surface, whereas, in the inner layer, the co-existence of Mg(OH)2, MgO and MgCO3 species was observed for both alloys. The presence of Al3+ in the surface electrolyte to form Al2O3/Al(OH)3 and the formation of carbonate product provide a better passivation on the surfaces and retard the chloride-induced corrosion on the materials in the passivation zone.

  17. Active galactic nuclei

    CERN Document Server

    Beckmann, Volker

    2012-01-01

    This AGN textbook includes phenomena based on new results in the X-Ray domain from new telescopes such as Chandra and XMM Newton not mentioned in any other book. Furthermore, it considers also the Fermi Gamma Ray Space Telescope with its revolutionary advances of unprecedented sensitivity, field of view and all-sky monitoring. Those and other new developments as well as simulations of AGN merging events and formations, enabled through latest super-computing capabilities. The book gives an overview on the current knowledge of the Active Galacitc Nuclei phenomenon. The spectral energy d

  18. Active galactic nuclei

    CERN Document Server

    Blandford, RD; Woltjer, L

    1990-01-01

    Starting with this volume, the Lecture Notes of the renowned Advanced Courses of the Swiss Society for Astrophysics and Astronomy will be published annually. In each course, three extensive lectures given by leading experts in their respective fields cover different and essential aspects of the subject. The 20th course, held at Les Diablerets in April 1990, dealt with current research on active galactic nuclei; it represents the most up-to-date views on the subject, presented with particular regard for clarity. The previous courses considered a wide variety of subjects, beginning with ""Theory

  19. Particles and nuclei, letters

    International Nuclear Information System (INIS)

    The present collection of letters from JINR, Dubna, contains eight separate records on the interaction of high energy Λ6He hypernuclear beams with atomic nuclei, the position-sensitive detector of a high spatial resolution on the basis of a multiwire gas electron multiplier, pseudorapidity hadron density at the LHC energy, high precision laser control of the ATLAS tile-calorimeter module mass production at JINR, a new approach to ECG's features recognition involving neural network, subcriticity of a uranium target enriched in 235U, beam space charge effects in high-current cyclotron injector CI-5, a homogeneous static gravitational field and the principle of equivalence

  20. Particles and nuclei, letters

    International Nuclear Information System (INIS)

    The present collection of letters from JINR, Dubna, contains six separate records on the DELPHI experiment at LEP, the Fermi-surface dynamics of rotating nuclei, production of large samples of the silica dioxide aerogel in the 37-litre autoclave and test of its optical properties, preliminary radiation resource results on scintillating fibers, a new algorithm for the direct transformation method of time to digital with the high time resolution and development and design of analogue read-out electronics for HADES drift chamber system

  1. Photoabsorption on nuclei

    OpenAIRE

    Effenberger, M.; Hombach, A; Teis, S.; Mosel, U.

    1996-01-01

    We calculate the total photoabsorption cross section on nuclei in the energy range from 300 MeV to 1 GeV within the framework of a semi-classical phase space model. Besides medium modifications like Fermi motion and Pauli blocking we focus on the collision broadening of the involved resonances. The resonance contributions to the elementary cross section are fixed by fits to partial wave amplitudes of pion photoproduction. The cross sections for $N \\, R \\to N \\, N$, needed for the calculation ...

  2. Low-Luminosity Seyfert Nuclei

    CERN Document Server

    Ho, L C; Sargent, W L W; Ho, Luis C.; Filippenko, Alexei V.; Sargent, Wallace L. W.

    1996-01-01

    We describe a new sample of Seyfert nuclei discovered during the course of an optical spectroscopic survey of nearby galaxies. The majority of the objects, many recognized for the first time, have luminosities much lower than those of classical Seyferts and populate the faint end of the AGN luminosity function. A significant fraction of the nuclei emit broad H-alpha emission qualitatively similar to the broad lines seen in classical Seyfert 1 nuclei and QSOs.

  3. Electron scattering for exotic nuclei

    Indian Academy of Sciences (India)

    Toshimi Suda

    2014-11-01

    A brand-new electron scattering facility, the SCRIT Electron Scattering Facility, will soon start its operation at RIKEN RI Beam Factory, Japan. This is the world’s first electron scattering facility dedicated to the structure studies of short-lived nuclei. The goal of this facility is to determine the charge density distributions of short-lived exotic nuclei by elastic electron scattering. The first collision between electrons and exotic nuclei will be observed in the year 2014.

  4. The dynamics of the nuclei-nuclei interactions at very high energies

    International Nuclear Information System (INIS)

    The lectures on the dynamics of nuclei-nuclei interactions at very high energies, presented in the Summer School on Nuclear Physics and Particle Physics (1988), are shown. The equation of state of the hadronic matter is analyzed, by means of simple models, and some orders of magnitude can be asserted. The main characteristics of the high energy hadronic interactions are recalled. The basis of the dynamics of the relativistic fluids are given. Applications of this dynamics in the description of the space-time evolution of a plasma, generated by heavy ions collision, are carried out

  5. Photodisintegration of p-process nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, A.; Nair, C.; Erhard, M.; Bemmerer, D.; Beyer, R.; Junghans, A.; Kosev, K.; Rusev, G.; Schilling, K.D.; Schwengner, R. [Forschungszentrum Dresden-Rossendorf, 01314 Dresden (Germany); Grosse, E. [Forschungszentrum Dresden-Rossendorf, 01314 Dresden (Germany); Technische Universitaet Dresden, 01062 Dresden (Germany)

    2009-07-01

    The neutron deficient p-nuclei are shielded from the s- or r-process by stable isotopes. P-nuclei are likely to be formed in high temperature cosmic scenarios like exploding supernovae by photodisintegration reactions on heavy r- or s- seed nuclei. The lack of experimental information on energy-dependent cross sections especially for ({gamma},p) and ({gamma},{alpha}) reactions reduces the applicability of nucleosynthesis models. Using intense bremsstrahlung produced at the superconducting electron linear accelerator ELBE at Forschungszentrum Dresden-Rossendorf we investigated ({gamma},n), ({gamma},p) and ({gamma},{alpha}) reactions for the medium-mass p-nuclei {sup 92}Mo and {sup 144}Sm, as well as ({gamma},n) reactions for {sup 100}Mo and {sup 154}Sm by photo-activation. The lowest photoactivation yields have been measured in an underground laboratory. The photodisintegration of {sup 197}Au serves as a benchmark and it is compared to data measured previously with the positron annihilation technique.

  6. Spectroscopic Studies of Exotic Nuclei at ISOLDE

    CERN Multimedia

    2002-01-01

    Experiment IS50 is designed to: a) Investigate the full range of the @b strength function of heavy (A~$>$~48)~K nuclei b)~Study the decay of isomeric states in n-deficient bromine nuclei (A~=~72 and 70). The heavy K isotopes appeared to have complex decay schemes, including feeding by the @b-decay of levels having open neutron channels (Beta decay energy Q(@b) exceeds neutron binding energy S^n); in addition, a large fraction of the delayed transitions populate excited levels in the daughter nuclei. The allowed @b-decay selects states in the daughter nucleus with wave functions having a large overlap with the initial state. Hence, the @b strength functions, deduced from these deca reveal simple structures correlated to the particle-hole excitation energies in the Ca nuclei. These results are valuable for the application of the shell-model calculations far from stability. The delayed neutron spectra are measured with a large area curved scintillator in coincidence either with high resolution Ge(Li) detectors, ...

  7. Four-body correlations in nuclei

    CERN Document Server

    Sambataro, M

    2015-01-01

    Low-energy spectra of 4$n$ nuclei are described with high accuracy in terms of four-body correlated structures ("quartets"). The states of all $N\\geq Z$ nuclei belonging to the $A=24$ isobaric chain are represented as a superposition of two-quartet states, with quartets being characterized by isospin $T$ and angular momentum $J$. These quartets are assumed to be those describing the lowest states in $^{20}$Ne ($T_z$=0), $^{20}$F ($T_z$=1) and $^{20}$O ($T_z$=2). We find that the spectrum of the self-conjugate nucleus $^{24}$Mg can be well reproduced in terms of $T$=0 quartets only and that, among these, the $J$=0 quartet plays by far the leading role in the structure of the ground state. The same conclusion is drawn in the case of the three-quartet $N=Z$ nucleus $^{28}$Si. As an application of the quartet formalism to nuclei not confined to the $sd$ shell, we provide a description of the low-lying spectrum of the proton-rich $^{92}$Pd. The results achieved indicate that, in 4$n$ nuclei, four-body degrees of f...

  8. Tank 241-AZ-102 Privatization Push Mode Core Sampling and Analysis Plan

    International Nuclear Information System (INIS)

    This sampling and analysis plan (SAP) identifies characterization objectives pertaining to sample collection, laboratory analytical evaluation, and reporting requirements for samples obtained from tank 241-AZ-102

  9. 241-AZ Tank Farm Construction Extent of Condition Review for Tank Integrity

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, Travis J.; Boomer, Kayle D.; Gunter, Jason R.; Venetz, Theodore J.

    2013-07-30

    This report provides the results of an extent of condition construction history review for tanks 241-AZ-101 and 241-AZ-102. The construction history of the 241-AZ tank farm has been reviewed to identify issues similar to those experienced during tank AY-102 construction. Those issues and others impacting integrity are discussed based on information found in available construction records, using tank AY-102 as the comparison benchmark. In the 241-AZ tank farm, the second DST farm constructed, both refractory quality and tank and liner fabrication were improved.

  10. The Role of Calcium in Microstructural Refinement of AZ91 Magnesium Alloy

    Institute of Scientific and Technical Information of China (English)

    LIU Shengfa; KANG Liugen; HAN Hui; WANG Zhongfan

    2006-01-01

    The effect of calcium addition on the microstructures of AZ91 magnesium alloy was investigated. It was found that a small amount of calcium in AZ91 alloy produced a large decrease in the a-Mg grain size and the dispersed fine β-Mg17 Al12 phases. In addition, some Al4 Ca particles were found to exist in the AZ91 alloy containing 0.5 wt% Ca. EDS analysis and water-quenched technique revealed that the grain-refining mechanism of calcium for the AZ91 alloys was mainly attributed to the role of restricting growth of calcium in the primary a-Mg crystals.

  11. Nuclear magnetic resonance of thermally oriented nuclei

    International Nuclear Information System (INIS)

    The more recent developments in the spectroscopy of Nuclear Magnetic Resonance on Oriented Nuclei (NMRON) are reviewed; both theoretical and experimental advances are summarised with applications to On-Line and Off-Line determination of magnetic dipole and electric quadrupole hyperfine parameters. Some emphasis is provided on solid state considerations with indications of where likely enhancements in technique will lead in conventional hyperfine studies. (orig.)

  12. Development of the helium-jet fed on-line mass separator RAMA and its application to studies of T/sub z/ = -2 nuclei

    International Nuclear Information System (INIS)

    The study of nuclei far from beta stability is hampered greatly when the nuclide of interest decays in a manner identical to that of a nuclide produced in greater yield in the same bombardment. Attempts to observe the protons associated with the decay of the A = 4n, T/sub z/ = -2 series of beta-delayed proton emitters failed because of the large number of protons arising from the strong beta-delayed proton decay of the A = 4n + 1, T/sub z/ = -3/2 nuclides. One solution to this problem is through the use of an on-line mass separator. Development of the Berkelely helium-jet fed on-line mass separator RAMA is discussed as applied to studies of the A = 4n, T/sub z/ = -2 nuclides. RAMA (Recoil Atom Mass Analyzer) has typical efficiencies of 0.1% for approx. 75 elements with melting points less than or equal to 20000C. This efficiency permits decay studies to be readily performed on nuclei with production cross sections greater than or equal to 500 μb for γ-ray spectroscopy and greater than or equal to 1 μb for discrete energy charged particle spectroscopy. The mass range on the normalized RAMA focal plane is +- 10%. The quoted efficiency is for a mass resolution of M/ΔM approx. 300. RAMA has been used to observe two members of the A = 4n, T/sub z/ = -2 series of beta-delayed proton emitters, 20Mg and 24Si. Observation of beta-delayed protons from a mass-separated sample of 20Mg(t/sub 1/2/ approx. 95 ms) establishes the mass-excess of the lowest T = 2 (0+) state in 20Na (13.42 +- .05 MeV), thereby completing the mass twenty isospin quintet. A similar measurement of the decay of 24Si (t/sub 1/2/ approx. 100 ms) establishes the mass-excess of the lowest T = 2 (0+) state in 24Al (5.903 +- 0.009 MeV). The mass 24 isospin quintet is incomplete because the mass of 24Si remains unknown

  13. AZ INTEGRÃ LT IGAZGATÃ SI ÉS ELLENÅ RZÉSI RENDSZER HATÉKONYSÃ GA AZ EU-BAN

    OpenAIRE

    Vasary, Viktoria

    2005-01-01

    Az Európai Unió Közös Agrárpolitikára fordított kiadásainak szabálytalanul és jogtalanul kifizetett (4000 euró feletti) tételeit a tagállamok kötelesek jelenteni az EU Bizottságának. Az EU Számvevőszéke által legutóbb elkészített külön je-lentés alapján az 1971 és 2002 között megállapított szabálytalan kifizetések visz-szafizetési folyamata az összeg 75%-át érintő mértékben még mindig „függőben†van. A kérdés jelenleg az, hogy az 1992. évi reformot követő, a támogatási szer-kezetben dominá...

  14. CO2 and diode laser welding of AZ31 magnesium alloy

    International Nuclear Information System (INIS)

    Magnesium alloys are being increasingly used in automotive and aerospace structures. Laser welding is an important joining method in such applications. There are several kinds of industrial lasers available at present, including the conventional CO2 and Nd:YAG lasers as well as recently available high power diode lasers. A 1.5 kW diode laser and a 2 kW CO2 laser are used in the present study for the welding of AZ31 alloys. It is found that different welding modes exist, i.e., keyhole welding with the CO2 laser and conduction welding with both the CO2 and the diode lasers. This paper characterizes welds in both welding modes. The effect of beam spot size on the weld quality is analyzed. The laser processing parameters are optimized to obtain welds with minimum defects

  15. Effect of rolling temperature of the magnesium alloy AZ31B formability

    International Nuclear Information System (INIS)

    The magnesium alloy AZ31B presents an interesting set of properties, which makes it potential candidate for applications in automotive and aeronautics. The main limitation of magnesium alloys is the low capacity of plastic forming at room temperature. The main motivation of this project is to understand and control the microstructure and crystallographic texture of magnesium alloys, to improve their formability. The effect of rolling temperature on the formability of the alloy was studied in this stage of the project. The alloy in the form of annealed and recrystallized sheets (2 mm thick) was deformed by rolling at four different temperatures: 25, 100, 200 and 250 deg C. The microstructural characterization was achieved using several complementary techniques of microstructural analysis, such as optical microscopy, scanning electron microscopy, X-ray analysis by energy dispersive, X-ray diffraction and microhardness. Results about the effect of rolling temperature on the alloy formability were presented and discussed. (author)

  16. Investigation of the chemical vicinity of defects in Mg and AZ31 with positron coincident Doppler boarding spectroscopy

    International Nuclear Information System (INIS)

    Within the scope of the present work, two main goals have been achieved: Firstly, the coincident Doppler broadening spectrometer (CDBS) at the high intense positron source NEPOMUC has been elaborately improved in order to increase the spatial resolution for defect mapping measurements and to investigate samples with shallow positron trapping sites which are present e. g. in magnesium. Secondly, as an application, the chemical vicinity of defects in the industrially used magnesium based alloy AZ31 has been examined by means of the detailed investigation of ion-irradiated specimen with positron annihilation spectroscopy. Detailed simulations with the finite-element simulation tool COMSOL were used to optimize the focal diameter of the positron beam at the sample position in order to increase the spatial resolution. With a value of 0.3 mm, sub-mm resolution has now been reached. The CDBS has been furthermore equipped with a sample cooling unit in order to reach liquid nitrogen temperature, maintaining the feature of scanning the sample for defect mapping. Defects and their chemical surrounding in ion irradiated magnesium and the magnesium based alloy AZ31 were then investigated on an atomic scale with the CDBS. In the respective spectra the chemical information and the defect contribution have been thoroughly separated. For this purpose, samples of annealed Mg were irradiated with Mg-ions in order to create exclusively defects. In addition Al- and Zn-ion irradiations on Mg-samples were performed in order to create samples with both defects and impurity atoms. The ion irradiated area on the samples was investigated with laterally and depth resolved positron Doppler broadening spectroscopy (DBS) and compared with SRIM-simulations of the vacancy distribution. The investigation of the chemical vicinity of crystal defects in AZ31 was performed with CDBS on Mg-ion irradiated AZ31 with Mg-ion irradiated Mg. The outer tail of the energy distribution in the annihilation

  17. Mussel-inspired functionalization of PEO/PCL composite coating on a biodegradable AZ31 magnesium alloy.

    Science.gov (United States)

    Tian, Peng; Xu, Demin; Liu, Xuanyong

    2016-05-01

    immersion in SBF. The initial cell adhesion and spread were also improved by the polydopamine. By further immobilizing polyhexamethylene biguanidine (PHMB) onto the coating surface via the assistance of polydopamine, good antibacterial ability was obtained. This feasible method for fabricating a cytocompatible and antibacterial composite coating on a biodegradable AZ31 alloy may be promising in implant applications due to the osteointegration and anti-infection properties of these materials post operation. PMID:26874118

  18. Dynamic effects in MAS and MQMAS NMR spectra of half-integer quadrupolar nuclei: calculations and an application to the double perovskite cryolite.

    Science.gov (United States)

    Kotecha, Mrignayani; Chaudhuri, Santanu; Grey, Clare P; Frydman, Lucio

    2005-11-30

    Dynamic processes such as chemical exchange or rotations between inequivalent orientations can affect the magic-angle spinning (MAS) and the multiple-quantum (MQ) MAS NMR spectra of half-integer quadrupolar nuclei. The present paper discusses such dynamic multisite MAS and MQMAS effects and applies them to study the dynamic processes that occur in the double perovskite cryolite, Na3AlF6. Dynamic line shape simulations invoking a second-order broadening of the central transition and relying on the semiclassical Bloch-McConnell formalism for chemical exchange were performed for a variety of exchange models possessing different symmetries. Fitting experimental variable-temperature cryolite 23Na NMR data with this formalism revealed that the two inequivalent sodium sites in this mineral undergo an exchange characterized by a broad distribution of rates. To further assess this dynamic process a variety of 27Al and 19F MAS NMR studies were also undertaken; quantitative 27Al-19F dipolar coupling measurements then revealed a dynamic motion of the AlF6 octahedra that were qualitatively consistent with predictions stemming from molecular dynamic simulations on this double perovskite. PMID:16305261

  19. Particles and nuclei, letters

    International Nuclear Information System (INIS)

    The present collection of letters from JINR, Dubna, contains ten separate records on the properties of the N=82 even-even nuclei, an investigation of the charge collection for strongly irradiated silicon strip detectors of the CMS ECAL preshower, the rate capability of the CSC cathode readout electronics, the timing resolution of cathode strip chambers of the CMS ME1/1 muon station and bunch crossing identification, strengthening and damping of synchrotron oscillations, photoradiation hardness of organic scintillators, as well as on a method of anode wire incident angle calculation of the first muon station (ME1/1) of the Compact Muon Solenoid set-up (CMS), heavy ion studies with CMS HF calorimeter, an investigation of the possibility of developing iodine-containing treatment and prophylactic pharmaceuticals based on blue-green algae Spirulina platensis using neutron activation analysis, a comparison between schemes for heavy ion injection into Nuclotron booster

  20. Particles and nuclei, letters

    International Nuclear Information System (INIS)

    The present collection of letters from JINR, Dubna, contains nine separate records on the transport of the evanescent electron beam in the vacuum section with plasma disks, determination of ΔΓs from analysis of untagged decays Bs0→J/ψφ by using the method of angular moments, investigation of light nucleus clustering in relativistic multifragmentation processes, secondary fragments of relativistic 22Ne at 4.1 A · GeV/c nuclei in nuclear emulsion, extrapolation of experimental data of accelerated radiation aging to the operation condition of dipole magnet electrical insulation at low dose rates, automatic quality control system of the installed straws into TRT wheels, a new method of fast simulation for a hadron calorimeter response, empirical evidence for relation between threshold effects and neutron strength function as well as on what information can be derived when no events are registered

  1. Particles and nuclei, letters

    International Nuclear Information System (INIS)

    The present collection of letters from JINR, Dubna, contains seven separate records on the integral representation for structure functions and target mass effects, multiscale properties of DNA primary structure including cross-scale correlations, dissipative evolution of the elementary act, the fine structure of the MT=1 Gamow-Teller resonance in 147gTb→147Gd β+/EC decay, the behaviour of the TVO temperature sensors in the magnetic fields, a fast method for searching for tracks in multilayer drift chambers of HADES spectrometer, a novel approach to particle track etching including surfactant enhanced control of pore morphology, azimuthal correlations of secondary particles in 32S induced interactions with Ag(Br) nuclei at 4.5 GeV/ c/ nucleon

  2. Particles and nuclei, letters

    International Nuclear Information System (INIS)

    The present collection of letters from JINR, Dubna, contains ten separate records on Wien filter using in exploring on low-energy radioactive nuclei, memory effects in dissipative nucleus-nucleus collision, topological charge and topological susceptibility in connection with translation and gauge invariance, solutions of the multitime Dirac equation, the maximum entropy technique. System's statistical description, the charged conductor inside dielectric. Solution of boundary condition by means of auxiliary charges and the method of linear algebraic equations, optical constants of the TGS single crystal irradiated by power pulsed electron beam, interatomic pair potential and n-e amplitude from slow neutron scattering by noble gases, the two-coordinate multiwire proportional chamber of the high spatial resolution and neutron drip line in the region of O-Mg isotopes

  3. Pulsars: gigantic nuclei

    International Nuclear Information System (INIS)

    What is the real nature of pulsars? This is essentially a question of the fundamental strong interaction between quarks at low-energy scale and hence of the non-perturbative quantum chromo-dynamics, the solution of which would certainly be meaningful for us to understand one of the seven millennium prize problems (i.e., "Yang-Mills Theory") named by the Clay Mathematical Institute. After a historical note, it is argued here that a pulsar is very similar to an extremely big nucleus, but is a little bit different from the gigantic nucleus speculated 80 years ago by L. Landau. The paper demonstrates the similarity between pulsars and gigantic nuclei from both points of view: the different manifestations of compact stars and the general behavior of the strong interaction. (author)

  4. Exotic nuclei in supernovae

    International Nuclear Information System (INIS)

    In this talk I discuss properties of hot stellar matter at sub-nuclear densities which is formed in supernova explosions. I emphasize that thermodynamic conditions in this case are rather similar to those created in the laboratory by intermediate-energy heavy-ion collisions. Theoretical methods developed for the interpretation of multi-fragment final states in such reactions can be used also for description of the stellar matter. I present main steps of the statistical approach to the equation of state and nuclear composition, dealing with an ensemble of nuclear species instead of one “average” nucleus. Finally some results of this approach are presented. The emphasis is put on possible formation of heavy and superheavy nuclei. (author)

  5. Gluon density in nuclei

    CERN Document Server

    Ayala, A P; Levin, E M

    1996-01-01

    In this talk we present our detail study ( theory and numbers) [1] on the shadowing corrections to the gluon structure functions for nuclei. Starting from rather contraversial information on the nucleon structure function which is originated by the recent HERA data, we develop the Glauber approach for the gluon density in a nucleus based on Mueller formula [2] and estimate the value of the shadowing corrections in this case. Than we calculate the first corrections to the Glauber approach and show that these corrections are big. Based on this practical observation we suggest the new evolution equation which takes into account the shadowing corrections and solve it. We hope to convince you that the new evolution equation gives a good theoretical tool to treat the shadowing corrections for the gluons density in a nucleus and, therefore, it is able to provide the theoretically reliable initial conditions for the time evolution of the nucleus - nucleus cascade.

  6. Clusters in nuclei

    CERN Document Server

    Beck, Christian

    Following the pioneering discovery of alpha clustering and of molecular resonances, the field of nuclear clustering is today one of those domains of heavy-ion nuclear physics that faces the greatest challenges, yet also contains the greatest opportunities. After many summer schools and workshops, in particular over the last decade, the community of nuclear molecular physicists has decided to collaborate in producing a comprehensive collection of lectures and tutorial reviews covering the field. This third volume follows the successful Lect. Notes Phys. 818 (Vol. 1) and 848 (Vol. 2), and comprises six extensive lectures covering the following topics:  - Gamma Rays and Molecular Structure - Faddeev Equation Approach for Three Cluster Nuclear Reactions - Tomography of the Cluster Structure of Light Nuclei Via Relativistic Dissociation - Clustering Effects Within the Dinuclear Model : From Light to Hyper-heavy Molecules in Dynamical Mean-field Approach - Clusterization in Ternary Fission - Clusters in Light N...

  7. Collective excitations in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Chomaz, Ph. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France); Collaboration: La Direction des Sciences de la Matiere du CEA (FR); Le Fonds National de la Recherche Scientifique de Belgique (BE)

    1998-12-31

    The properties of the nucleus cannot be reduced to the properties of its constituents: it is a complex system. The fact that many properties of the nucleus are consequences of the existence of mean-field potential is a manifestation of this complexity. In particular, the nucleons can thus self-organize in collective motions such as giant resonances. Therefore the study of this collective motions is a very good tool to understand the properties of the nucleus itself. The purpose of this article is to stress some aspects of these collective vibrations. We have studied how an ensemble of fermions as the nucleus can self-organize in collective vibrations which are behaving like a gas of bosons in weak interaction. Understanding of these phenomena remains one of the important subjects of actuality in the context of quantal systems in strong interaction. In particular, the study of the states with one or two vibration quanta provides a direct information on the structure of nuclei close to their ground states. Moreover, some collective states appear to be very robust against the onset of chaos. This is the case of the hot giant dipole built on top of a hot nucleus which seems to survive up to rather high temperatures. Their sudden disappearance is still a subject of controversy. It may be that the mean-field and the associated collective states are playing a crucial role also in catastrophic processes such as the phase-transitions. Indeed, when the system is diluted the collective vibrations may become unstable and it seems that these unstable modes provide a natural explanation to the self organization of the system in drops. Finally, considering the diversity of the different structures of exotic nuclei one may expect new vibration types. All these studies are showing the diversity of the collective motions of strongly correlated quantum systems such as the nucleus but many open questions remain to be solved. (authors) 304 refs., 53 figs., 5 tabs.

  8. Collective excitations in nuclei

    International Nuclear Information System (INIS)

    The properties of the nucleus cannot be reduced to the properties of its constituents: it is a complex system. The fact that many properties of the nucleus are consequences of the existence of mean-field potential is a manifestation of this complexity. In particular, the nucleons can thus self-organize in collective motions such as giant resonances. Therefore the study of this collective motions is a very good tool to understand the properties of the nucleus itself. The purpose of this article is to stress some aspects of these collective vibrations. We have studied how an ensemble of fermions as the nucleus can self-organize in collective vibrations which are behaving like a gas of bosons in weak interaction. Understanding of these phenomena remains one of the important subjects of actuality in the context of quantal systems in strong interaction. In particular, the study of the states with one or two vibration quanta provides a direct information on the structure of nuclei close to their ground states. Moreover, some collective states appear to be very robust against the onset of chaos. This is the case of the hot giant dipole built on top of a hot nucleus which seems to survive up to rather high temperatures. Their sudden disappearance is still a subject of controversy. It may be that the mean-field and the associated collective states are playing a crucial role also in catastrophic processes such as the phase-transitions. Indeed, when the system is diluted the collective vibrations may become unstable and it seems that these unstable modes provide a natural explanation to the self organization of the system in drops. Finally, considering the diversity of the different structures of exotic nuclei one may expect new vibration types. All these studies are showing the diversity of the collective motions of strongly correlated quantum systems such as the nucleus but many open questions remain to be solved. (authors)

  9. Quarks in Few Body Nuclei

    Directory of Open Access Journals (Sweden)

    Holt Roy J.

    2016-01-01

    Full Text Available Electron scattering at very high Bjorken x from hadrons provides an excellent test of models, has an important role in high energy physics, and from nuclei, provides a window into short range correlations. Light nuclei have a key role because of the relatively well-known nuclear structure. The development of a novel tritium target for Jefferson Lab has led to renewed interest in the mass three system. For example, deep inelastic scattering experiments in the light nuclei provide a powerful means to determine the neutron structure function. The isospin dependence of electron scattering from mass-3 nuclei provide information on short range correlations in nuclei. The program using the new tritium target will be presented along with a summary of other experiments aimed at revealing the large-x structure of the nucleon.

  10. Quarks in Few Body Nuclei

    Science.gov (United States)

    Holt, Roy J.

    2016-03-01

    Electron scattering at very high Bjorken x from hadrons provides an excellent test of models, has an important role in high energy physics, and from nuclei, provides a window into short range correlations. Light nuclei have a key role because of the relatively well-known nuclear structure. The development of a novel tritium target for Jefferson Lab has led to renewed interest in the mass three system. For example, deep inelastic scattering experiments in the light nuclei provide a powerful means to determine the neutron structure function. The isospin dependence of electron scattering from mass-3 nuclei provide information on short range correlations in nuclei. The program using the new tritium target will be presented along with a summary of other experiments aimed at revealing the large-x structure of the nucleon.

  11. Histone H2A (H2A.X and H2A.Z variants in molluscs: molecular characterization and potential implications for chromatin dynamics.

    Directory of Open Access Journals (Sweden)

    Rodrigo González-Romero

    Full Text Available Histone variants are used by the cell to build specialized nucleosomes, replacing canonical histones and generating functionally specialized chromatin domains. Among many other processes, the specialization imparted by histone H2A (H2A.X and H2A.Z variants to the nucleosome core particle constitutes the earliest response to DNA damage in the cell. Consequently, chromatin-based genotoxicity tests have been developed in those cases where enough information pertaining chromatin structure and dynamics is available (i.e., human and mouse. However, detailed chromatin knowledge is almost absent in most organisms, specially protostome animals. Molluscs (which represent sentinel organisms for the study of pollution are not an exception to this lack of knowledge. In the present work we first identified the existence of functionally differentiated histone H2A.X and H2A.Z variants in the mussel Mytilus galloprovincialis (MgH2A.X and MgH2A.Z, a marine organism widely used in biomonitoring programs. Our results support the functional specialization of these variants based on: a their active expression in different tissues, as revealed by the isolation of native MgH2A.X and MgH2A.Z proteins in gonad and hepatopancreas; b the evolutionary conservation of different residues encompassing functional relevance; and c their ability to confer specialization to nucleosomes, as revealed by nucleosome reconstitution experiments using recombinant MgH2A.X and MgH2A.Z histones. Given the seminal role of these variants in maintaining genomic integrity and regulating gene expression, their preliminary characterization opens up new potential applications for the future development of chromatin-based genotoxicity tests in pollution biomonitoring programs.

  12. On the deformation twinning of Mg AZ31B

    DEFF Research Database (Denmark)

    Abdolvand, Hamidreza; Majkut, Marta; Oddershede, Jette;

    2015-01-01

    Crystals with a hexagonal close-packed (HCP) structure are inherently anisotropic, and have a limited number of independent slip systems, which leads to strong deformation textures and reduced formability in polycrystalline products. Tension along the c-axis of the crystal ideally activates...... extension twinning as a deformation mode due to the lack of easy-slip systems. In this work, experiments were devised to study extension twinning in a polycrystalline Mg alloy AZ31B with a strong basal rolling texture by tensile deformation parallel to the plate normal. Three-dimensional synchrotron X...

  13. 78 FR 65370 - Notice of Inventory Completion: Pima County Office of the Medical Examiner, Tucson, AZ

    Science.gov (United States)

    2013-10-31

    ... been placed with or near individual human remains at the time of death or later as part of the death... objects were removed from a location near the town of San Manuel, Pinal County, AZ. This notice is... were removed from a river wash near San Manuel in Pinal County, AZ. The remains were removed from...

  14. Genome Sequence of the Acidophilic Bacterium Acidocella sp. Strain MX-AZ02

    DEFF Research Database (Denmark)

    Servín-Garcidueñas, Luis E.; Garrett, Roger A.; Amils, Ricardo;

    2013-01-01

    Here, we report the draft genome sequence of Acidocella sp. strain MX-AZ02, an acidophilic and heterotrophic alphaproteobacterium isolated from a geothermal lake in western Mexico.......Here, we report the draft genome sequence of Acidocella sp. strain MX-AZ02, an acidophilic and heterotrophic alphaproteobacterium isolated from a geothermal lake in western Mexico....

  15. In vitro degradation behavior and cytocompatibility of biodegradable AZ31 alloy with PEO/HT composite coating.

    Science.gov (United States)

    Tian, Peng; Liu, Xuanyong; Ding, Chuanxian

    2015-04-01

    Biodegradable magnesium-based implants have attracted much attention recently in orthopedic applications because of their good mechanical properties and biocompatibility. However, their rapid degradation in vivo will not only reduce their mechanical strength, but also induce some side effects, such as local alkalization and gas cavity, which may lead to a failure of the implant. In this work, a hydroxyapatite (HA) layer was prepared on plasma electrolytic oxidization (PEO) coating by hydrothermal treatment (HT) to fabricate a PEO/HT composite coating on biodegradable AZ31 alloy. The in vitro degradation behaviors of all samples were evaluated in simulated body fluid (SBF) and their surface cytocompatibility was also investigated by evaluating the adhesion and proliferation of osteoblast cells (MC3T3-E1). The results showed that the HA layer consisted of a dense inner layer and a needle-like outer layer, which successfully sealed the PEO coating. The in vitro degradation tests showed that the PEO/HT composite coating improved the corrosion resistance of AZ31 alloy in SBF, presenting nearly no severe local alkalization and hydrogen evolution. The lasting corrosion resistance of the PEO/HT composite coating may attribute to the new hydroxyapatite formation during the degradation process. Moreover, compared with AZ31 alloy and PEO coating, PEO/HT composite coating was more suitable for cells adhesion and proliferation, indicating improved surface cytocompatibility. The results show that the PEO/HT composite coating is promising as protective coating on biodegradable magnesium-based implants to enhance their corrosion resistance as well as improve their surface cytocompatibility for orthopedic applications. PMID:25731092

  16. Influence of hot extrusion on microstructure and mechanical properties of AZ31 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    WANG Ling; TIAN Su-gui; MENG Fan-lai; DU Hong-qiang

    2006-01-01

    Extrusion treatment is a common method to refine the grain size and improve the mechanical properties of metal material. The influence of hot extrusion on microstructure and mechanical properties of AZ31 magnesium alloy was investigated. The results show that the mechanical properties of AZ31 alloy are obviously improved by extrusion treatment. The ultimate tensile strength (UTS) of AZ31 alloy at room temperature is measured to be 222 MPa, and is enhanced to 265.8 MPa after extrusion at 420℃. The yield tensile strength (YTS) of AZ31 alloy at room temperature is measured to be 84 MPa, and is enhanced to 201 MPa after extrusion at 420℃. The effective improvements on mechanical properties result from the formation of the finer grains during extrusion and the finer particles precipitated by age treatment. The features of the microstructure evolution during hot extruded of AZ31 alloy are dislocation slipping on the matrix and occurrence of the dynamic recrystallization.

  17. Corrosion behaviour and in vitro/in vivo biocompatibility of surface-modified AZ31 alloy

    International Nuclear Information System (INIS)

    The present work evaluates the corrosion behaviour and the in vitro/in vivo biocompatibility of the AZ31 magnesium alloy, which fulfills the mechanical requirements of bone. The corrosion kinetic of as-received AZ31 alloy was not compatible with the cell growth. To improve its performance, the AZ31 alloy was surface modified by a chemical conversion treatment in hydrofluoric acid. The magnesium fluoride layer generated by the surface treatment of AZ31 alloy enhances its corrosion behaviour, allowing the in vitro growth of osteoblastic cells over the surface and the in vivo formation of a highly compact layer of new bone tissue. These results lead to consider the magnesium fluoride coating as necessary for potential use of the AZ31 alloy as biodegradable and absorbable implant for bone repair. (Author) 18 refs.

  18. Examination of dynamic recrystallization during compression of AZ31 magnesium

    Institute of Scientific and Technical Information of China (English)

    XIN RenLong; WANG BingShu; CHEN XingPin; HUANG GuangJie; LIU Qing

    2009-01-01

    This study aimed to investigate dynamic recrystallization (DRX) behavior during compression of mag-nesium alloy AZ31. Cylinder samples were cut from the extruded rod and hot rolled sheet AZ31 for compression test. The samples were compressed using a Gleeble 1500D at a temperature of 300Ⅱ and a strain rate of 0.01 s-1. Grain orientations and misorientation angles across grain boundaries for the tested samples were obtained by using electron backscatter diffraction (EBSD) technique. The results showed that strong basal texture was observed after 50% compression (ε = 0.69) on both the extruded and hot rolled samples, which have different initial textures. It was observed that with increased strain, DRX grains gradually rotated to basal orientation, and grain boundaries with misorientation angle of near 30° was formed in the samples. At the strain of 0.69, a high fraction of high-angle (> 60°) bounda-ries was present in the extruded sample, whereas almost no high angle boundaries were observed in the hot rolled sheet sample.

  19. Examination of dynamic recrystallization during compression of AZ31 magnesium

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    This study aimed to investigate dynamic recrystallization (DRX) behavior during compression of magnesium alloy AZ31. Cylinder samples were cut from the extruded rod and hot rolled sheet AZ31 for compression test. The samples were compressed using a Gleeble 1500D at a temperature of 300℃ and a strain rate of 0.01 s-1. Grain orientations and misorientation angles across grain boundaries for the tested samples were obtained by using electron backscatter diffraction (EBSD) technique. The results showed that strong basal texture was observed after 50% compression (ε = 0.69) on both the extruded and hot rolled samples, which have different initial textures. It was observed that with increased strain, DRX grains gradually rotated to basal orientation, and grain boundaries with misorientation angle of near 30° was formed in the samples. At the strain of 0.69, a high fraction of high-angle (> 60°) bounda-ries was present in the extruded sample, whereas almost no high angle boundaries were observed in the hot rolled sheet sample.

  20. Development of AZS refractories for the glass industry

    International Nuclear Information System (INIS)

    Refractory materials can support high temperatures, thermal strength and the contact with aggressive environments, for this reason they are widely used in the cement, glass and steel industry. Commercial AZS (alumina-zirconia-silica) refractories are a good alternative in refractory materials for the glass industry' because they can support the aggressive conditions during liquid processing of glass. However, another problem encountered in glass industry is contamination by refractory' material that fall into the molten glass, which can produce a series of defects in the final product. This research was conducted to develop new formulations of AZS refractories with different amounts of ZrO2 with the purpose of improving the characteristics, properties and the work conditions in the glass melting furnaces and, at the same time, lower the costs this type of refractories. The results obtained indicate that the composition with low content of ZrO2 can provide better properties than the commercial product, with some modifications in the particle size distribution. Copyright (2004) AD-TECH - International Foundation for the Advancement of Technology Ltd

  1. Monopole transitions in hot nuclei

    International Nuclear Information System (INIS)

    Monopole transitions can be a signature of shape changing in a hot, pulsating nucleus (the low energy E0 mode) and/or a measure of the compressibility of finite nuclei (GMR, the breathing mode). Experimental information pertaining to GMR is reviewed. Recipes for deducing the incompressibility modules for infinite nuclear matter from data on GMR are discussed. Astrophysical implications are outlined. The first attempts at locating the GMR strength in moderately hot nuclei are described. Prospects for improving the experimental techniques to make an observation of this strength in selected nuclei unambiguous are discussed. (author). 46 refs, 8 figs

  2. Spectroscopy of heavy fissionable nuclei

    Indian Academy of Sciences (India)

    S K Tandel

    2015-09-01

    Structural studies of heavy nuclei are quite challenging due to increased competition from fission, particularly at high spins. Nuclei in the actinide region exhibit a variety of interesting phenomena. Recent advances in instrumentation and analysis techniques have made feasible sensitive measurements of nuclei populated with quite low cross-sections. These include isomers and rotational band structures in isotopes of Pu ( = 94) to Rf ( = 104), and octupole correlations in the Th ( = 90) region. The obtained experimental data have provided insights on various aspects like moments of inertia and nucleon alignments at high spins, quasiparticle energies and evolution of quadrupole and octupole collectivity, among others. An overview of some of these results is presented.

  3. Modeling level structures of odd-odd deformed nuclei

    International Nuclear Information System (INIS)

    A technique for modeling quasiparticle excitation energies and rotational parameters in odd-odd deformed nuclei has been applied to actinide species where new experimental data have been obtained by use of neutron-capture gamma-ray spectroscopy. The input parameters required for the calculation were derived from empirical data on single-particle excitations in neighboring odd-mass nuclei. Calculated configuration-specific values for the Gallagher-Moszkowski splittings were used. Calculated and experimental level structures for 238Np, 244Am, and 250Bk are compared, as well as those for several nuclei in the rare-earth region. The agreement for the actinide species is excellent, with bandhead energies deviating 22 keV and rotational parameters 5%, on the average. Corresponding average deviations for five rare-earth nuclei are 47 keV and 7%. Several applications of this modeling technique are discussed. 18 refs., 5 figs., 4 tabs

  4. Particles and nuclei, letters

    International Nuclear Information System (INIS)

    The present collection of letters from JINR, Dubna, contains ten separate records on the role of the Coulomb distortion in form-factor calculations for 12C with alpha-clusterization and nucleon-nucleon correlations, optimization of a set-up for the investigation of the light-nuclei spin structure at the internal target of the Nuclotron, precessing deuteron polarization, connection of the parameter estimation quality of maximum likelihood and generalized moments, determination of the total energy QEC for 156Ho(T1/2∼56 min)β+/EC decay using the total absorption γ-ray spectrometer, selection of signal events in the DUBTO experiment, a search for the dineutron in the interaction of neutrons with deuterons, tracking performance of the HERA-B outer tracker PC chambers, construction and manufacture of large size straw-chambers of the COMPASS spectrometer tracking system, as well as on the charge form factor and the nucleon momentum distribution of 24He and their centre-of-mass correction

  5. Collective excitations in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Chomaz, Ph

    1997-12-31

    The properties of the nucleus cannot be reduced to the properties of its constituents: it is a complex system. The fact that many properties of the nucleus are consequences of the existence of mean-field potential is a manifestation of this complexity. In particular the nucleons can thus self-organize in collective motions such as giant resonances. Therefore the study of these collective motions is a very good to understand the properties of the nucleus itself. The purpose of this article was to stress some aspects of these collective vibrations. In particular we have studied how an ensemble of fermions as the nucleus can self-organize in collective vibrations which are behaving like a gas of bosons in weak interaction. The understanding of these phenomena remains one of the important subjects of actually in the context of quantal systems in strong interaction. In particular the study of the states with one or two vibration quanta provides a direct information on the structure if nuclei close to their ground states. (author) 270 refs.

  6. Collective excitations in nuclei

    International Nuclear Information System (INIS)

    The properties of the nucleus cannot be reduced to the properties of its constituents: it is a complex system. The fact that many properties of the nucleus are consequences of the existence of mean-field potential is a manifestation of this complexity. In particular the nucleons can thus self-organize in collective motions such as giant resonances. Therefore the study of these collective motions is a very good to understand the properties of the nucleus itself. The purpose of this article was to stress some aspects of these collective vibrations. In particular we have studied how an ensemble of fermions as the nucleus can self-organize in collective vibrations which are behaving like a gas of bosons in weak interaction. The understanding of these phenomena remains one of the important subjects of actually in the context of quantal systems in strong interaction. In particular the study of the states with one or two vibration quanta provides a direct information on the structure if nuclei close to their ground states. (author)

  7. Antibaryons bound in nuclei

    CERN Document Server

    Mishustin, I N; Buervenich, T J; Stöcker, H; Greiner, W

    2005-01-01

    We study the possibility of producing a new kind of nuclear systems which in addition to ordinary nucleons contain a few antibaryons (antiproton, antilambda, etc.). The properties of such systems are described within the relativistic mean-field model by employing G-parity transformed interactions for antibaryons. Calculations are first done for infinite systems and then for finite nuclei from He to Pb. It is demonstrated that the presence of a real antibaryon leads to a strong rearrangement of a target nucleus resulting in a significant increase of its binding energy and local compression. Noticeable effects remain even after the antibaryon coupling constants are reduced by factor 3-4 compared to G-parity motivated values. We have performed detailed calculations of the antibaryon annihilation rates in the nuclear environment by applying a kinetic approach. It is shown that due to significant reduction of the reaction Q-values, the in-medium annihilation rates should be strongly suppressed leading to relativel...

  8. Gluon density in nuclei

    International Nuclear Information System (INIS)

    In this talk we present our detailed study (theory and numbers) on the shadowing corrections to the gluon structure functions for nuclei. Starting from rather controversial information on the nucleon structure function which is originated by the recent HERA data, we develop the Glauber approach for the gluon density in a nucleus based on Mueller formula and estimate the value of the shadowing corrections in this case. Then we calculate the first corrections to the Glauber approach and show that these corrections are big. Based on this practical observation we suggest the new evolution equation which takes into account the shadowing corrections and solve it. We hope to convince you that the new evolution equation gives a good theoretical tool to treat the shadowing corrections for the gluons density in a nucleus and, therefore, it is able to provide the theoretically reliable initial conditions for the time evolution of the nucleus-nucleus cascade. The initial conditions should be fixed both theoretically and phenomenologically before to attack such complicated problems as the mixture of hard and soft processes in nucleus-nucleus interactions at high energy or the theoretically reliable approach to hadron or/and parton cascades for high energy nucleus-nucleus interaction. 35 refs., 24 figs., 1 tab

  9. Gluon density in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Ayala, A.L. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica][Pelotas Univ., RS (Brazil). Inst. de Fisica e Matematica; Ducati, M.B.G. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica; Levin, E.M. [Fermi National Accelerator Lab., Batavia, IL (United States)][Nuclear Physics Inst., St. Petersburg (Russian Federation)

    1996-10-01

    In this talk we present our detailed study (theory and numbers) on the shadowing corrections to the gluon structure functions for nuclei. Starting from rather controversial information on the nucleon structure function which is originated by the recent HERA data, we develop the Glauber approach for the gluon density in a nucleus based on Mueller formula and estimate the value of the shadowing corrections in this case. Then we calculate the first corrections to the Glauber approach and show that these corrections are big. Based on this practical observation we suggest the new evolution equation which takes into account the shadowing corrections and solve it. We hope to convince you that the new evolution equation gives a good theoretical tool to treat the shadowing corrections for the gluons density in a nucleus and, therefore, it is able to provide the theoretically reliable initial conditions for the time evolution of the nucleus-nucleus cascade. The initial conditions should be fixed both theoretically and phenomenologically before to attack such complicated problems as the mixture of hard and soft processes in nucleus-nucleus interactions at high energy or the theoretically reliable approach to hadron or/and parton cascades for high energy nucleus-nucleus interaction. 35 refs., 24 figs., 1 tab.

  10. Fusion probability in heavy nuclei

    Science.gov (United States)

    Banerjee, Tathagata; Nath, S.; Pal, Santanu

    2015-03-01

    Background: Fusion between two massive nuclei is a very complex process and is characterized by three stages: (a) capture inside the potential barrier, (b) formation of an equilibrated compound nucleus (CN), and (c) statistical decay of the CN leading to a cold evaporation residue (ER) or fission. The second stage is the least understood of the three and is the most crucial in predicting yield of superheavy elements (SHE) formed in complete fusion reactions. Purpose: A systematic study of average fusion probability, , is undertaken to obtain a better understanding of its dependence on various reaction parameters. The study may also help to clearly demarcate onset of non-CN fission (NCNF), which causes fusion probability, PCN, to deviate from unity. Method: ER excitation functions for 52 reactions leading to CN in the mass region 170-220, which are available in the literature, have been compared with statistical model (SM) calculations. Capture cross sections have been obtained from a coupled-channels code. In the SM, shell corrections in both the level density and the fission barrier have been included. for these reactions has been extracted by comparing experimental and theoretical ER excitation functions in the energy range ˜5 %-35% above the potential barrier, where known effects of nuclear structure are insignificant. Results: has been shown to vary with entrance channel mass asymmetry, η (or charge product, ZpZt ), as well as with fissility of the CN, χCN. No parameter has been found to be adequate as a single scaling variable to determine . Approximate boundaries have been obtained from where starts deviating from unity. Conclusions: This study quite clearly reveals the limits of applicability of the SM in interpreting experimental observables from fusion reactions involving two massive nuclei. Deviation of from unity marks the beginning of the domain of dynamical models of fusion. Availability of precise ER cross sections over a wider energy range for

  11. Physics with loosely bound nuclei

    Indian Academy of Sciences (India)

    Chhanda Samanta

    2001-08-01

    The essential aspect of contemporary physics is to understand properties of nucleonic matter that constitutes the world around us. Over the years research in nuclear physics has provided strong guidance in understanding the basic principles of nuclear interactions. But, the scenario of nuclear physics changed drastically as the new generation of accelerators started providing more and more rare isotopes, which are away from the line of stability. These weakly bound nuclei are found to exhibit new forms of nuclear matter and unprecedented exotic behaviour. The low breakup thresholds of these rare nuclei are posing new challenges to both theory and experiments. Fortunately, nature has provided a few loosely bound stable nuclei that have been studied thoroughly for decades. Attempts are being made to find a consistent picture for the unstable nuclei starting from their stable counterparts. Some significant differences in the structure and reaction mechanisms are found.

  12. Collisions between complex atomic nuclei

    International Nuclear Information System (INIS)

    The use of heavy ion accelerators in the study of nuclear structure and states is reviewed. The reactions discussed are the quasielastic reactions in which small amounts of energy and few particles are exchanged between the colliding nuclei. The development of heavy ion accelerators is also discussed, as well as detection equipment. Exotic phenomena, principally the possible existence of superheavy nuclei, are also treated. (JIW)

  13. Particles and nuclei in PANIC

    International Nuclear Information System (INIS)

    PANIC is the triennal International Conference on Particles and Nuclei, and judging from the latest PANIC, held in Kyoto from 20-24 April there is no need for panic yet. Faced with two pictures – one of nuclei described in nucleon and meson terms, and another of nucleons containing quarks and gluons – physicists are intrigued to know what new insights from the quark level can tell us about nuclear physics, or vice versa

  14. Sturmian method for light exotic nuclei

    International Nuclear Information System (INIS)

    this intuitive prediction and also indicate that due to small binding energies it is important for other nuclei too. There was one more aspect connected to weak binding of Borromean systems that was emphasized in this work. This is the effect of nucleon mass parameter. A realistic atomic nucleus is a system composed of neutrons and protons. Considering the constituents of the nucleus as structureless identical fermions (i.e. nucleons) provides a very useful formalism, which leads to significant simplifications of our understanding and description of nuclear structure. These simplifications follow from the fact that the potentials of the strong neutron-neutron, neutron-proton and proton-proton interactions are also very similar. However, realistic kinetic energy operator and kinetic energy operator of the nucleus as a system of nucleons are different, in particular the latter contains the nucleon mass parameter which in many applications is defined as an average of the proton and neutron masses. For the nuclei at the neutron dripline due to large neutron to proton ratio this becomes a worse approximation. In this work it was investigated how binding energy and size of 6He and 14Be depend on the nucleon mass parameter and showed that while the size is little sensitive to the nucleon mass parameter, change in binding energy is not negligible. Last, but not least, one more observation is to be pointed out. The binding in halo nuclei results from a delicate balance between different forces and is very sensitive to this force choice. Except for 6He where core-n interaction is well known, because of the mentioned difficulties the reliability of the different core-nucleon forces is not clearly established yet. The sensitivity to the nn force is also not negligible, due to weak binding of Borromean nuclei. (Author)

  15. Investigation of copper nuclei

    International Nuclear Information System (INIS)

    An extensive study has been performed on copper isotopes in the mass region A=63-66. The results of a precise measurement are presented on the properties of levels of 64Cu and 66Cu. They were obtained by bombarding the 63Cu and 65Cu nuclei with neutrons. The gamma spectra collected after capture of thermal, 2-keV, 24-keV neutrons have been analysed and combined to give a rather extensive set of precise level energies and gamma transition strengths. From the angular distribution of the gamma rays it is possible to obtain information concerning the angular momentum J of several low-lying states. The level schemes derived from such measurements have been used as a test for calculations in the framework of the shell model. The spectral distributions of eigenstates in 64Cu for different configuration spaces are presented and discussed. In this study the relative importance of configurations with n holes in the 1f7/2 shell with n up to 16, are investigated. It is found that the results strongly depend on the values of the single-particle energies. The results of the spectral-distribution method were utilized for shell-model calculations. From the information obtained from the spectral analysis it was decided to adopt a configuration space which includes up to one hole in the 1f7/2 shell and up to two particles in the 1g9/2 shell. Further, restrictions on seniority and on the coupling of the two particles in the 1g9/2 orbit have been applied and their effects have been studied. It is found that the calculated excitation energies reproduce the measured values in a satisfactory way, but that some of the electromagnetic properties are less well in agreement with experimental data. (Auth.)

  16. A variety of kaonic nuclei

    International Nuclear Information System (INIS)

    We have investigated systematically kaonic nuclei which are ppnK-, pppK-, pppnK-, 6BeK-, 9BK- and 11CK-. Since I = 0 K-barN interaction, which is very attractive, plays an essential role in kaonic nuclei, we should treat it adequately. For this purpose, we have improved the framework of antisymmetrized molecular dynamics (AMD): 1) we can treat pK-/nK-bar0 mixing and 2) perform not only angular-momentum projection but also isospin projection. As a result of our calculation with a new framework of AMD, all kaonic nuclei we calculated are deeply bound by about 100 MeV as a discrete state. They have various structures with highly dense state. We have also investigated double kaonic nuclei, ppnK-K- and ppnK-K-. They are more shrunk than single kaonic nuclei, but the binding energy per single kaon (E(K-bar)) is about 100 MeV, which is equal to that in the case of single kaonic nuclei. (author)

  17. Controlling the degradation rate of AZ91 magnesium alloy via sol–gel derived nanostructured hydroxyapatite coating

    Energy Technology Data Exchange (ETDEWEB)

    Rojaee, Ramin, E-mail: raminrojaee@aim.com [Biomaterials Research Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan, 84156-83111 (Iran, Islamic Republic of); Fathi, Mohammadhossein [Biomaterials Research Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan, 84156-83111 (Iran, Islamic Republic of); Dental Materials Research Center, Isfahan University of Medical Sciences, Isfahan (Iran, Islamic Republic of); Raeissi, Keyvan [Department of Materials Engineering, Isfahan University of Technology, Isfahan, 84156-83111 (Iran, Islamic Republic of)

    2013-10-15

    Magnesium (Mg) alloys have been introduced as new generation of biodegradable orthopedic materials in recent years since it has been proved that Mg is one of the main minerals required for osseous tissue revival. The main goal of the present study was to establish a desired harmony between the necessities of orthopedic patient body to Mg{sup 2+} ions and degradation rate of the Mg based implants as a new class of biodegradable/bioresorbable materials. This prospect was followed by providing a sol–gel derived nanostructured hydroxyapatite (n-HAp) coating on AZ91 alloy using dip coating technique. Phase structural analysis, morphology study, microstructure characterization, and functional group identification were performed using X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. The prepared samples were immersed in simulated body fluid in order to study the formation of apatite-like precipitations, barricade properties of the n-HAp coating, and to estimate the dosage of released Mg{sup 2+} ions within a specified and limited time of implantation. Electrochemical polarization tests were carried out to evaluate and compare the corrosion behavior of the n-HAp coated and uncoated samples. The changes of the in vitro pH values were also evaluated. Results posed the noticeable capability of n-HAp coating on stabilizing alkalization behavior and improving the corrosion resistance of AZ91 alloy. It was concluded that n-HAp coated AZ91 alloy could be a good candidate as a type of biodegradable implant material for biomedical applications. - Highlights: • Nanostructured hydroxyapatite coatings were applied on Mg based alloy. • The whole corrosion process of Mg based alloy was controlled in body fluid. • This coating was able to act as a barrier against further release of Mg{sup 2+} ions. • The coating improved the stabilization of Mg alkalization behavior.

  18. Controlling the degradation rate of AZ91 magnesium alloy via sol–gel derived nanostructured hydroxyapatite coating

    International Nuclear Information System (INIS)

    Magnesium (Mg) alloys have been introduced as new generation of biodegradable orthopedic materials in recent years since it has been proved that Mg is one of the main minerals required for osseous tissue revival. The main goal of the present study was to establish a desired harmony between the necessities of orthopedic patient body to Mg2+ ions and degradation rate of the Mg based implants as a new class of biodegradable/bioresorbable materials. This prospect was followed by providing a sol–gel derived nanostructured hydroxyapatite (n-HAp) coating on AZ91 alloy using dip coating technique. Phase structural analysis, morphology study, microstructure characterization, and functional group identification were performed using X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. The prepared samples were immersed in simulated body fluid in order to study the formation of apatite-like precipitations, barricade properties of the n-HAp coating, and to estimate the dosage of released Mg2+ ions within a specified and limited time of implantation. Electrochemical polarization tests were carried out to evaluate and compare the corrosion behavior of the n-HAp coated and uncoated samples. The changes of the in vitro pH values were also evaluated. Results posed the noticeable capability of n-HAp coating on stabilizing alkalization behavior and improving the corrosion resistance of AZ91 alloy. It was concluded that n-HAp coated AZ91 alloy could be a good candidate as a type of biodegradable implant material for biomedical applications. - Highlights: • Nanostructured hydroxyapatite coatings were applied on Mg based alloy. • The whole corrosion process of Mg based alloy was controlled in body fluid. • This coating was able to act as a barrier against further release of Mg2+ ions. • The coating improved the stabilization of Mg alkalization behavior

  19. Spectrin-like proteins in plant nuclei

    NARCIS (Netherlands)

    Ruijter, de N.C.A.; Ketelaar, T.; Blumenthal, S.S.D.; Emons, A.M.C.; Schel, J.H.N.

    2000-01-01

    We analysed the presence and localization of spectrin-like proteins in nuclei of various plant tissues, using several anti-erythrocyte spectrin antibodies on isolated pea nuclei and nuclei in cells. Western blots of extracted purified pea nuclei show a cross-reactive pair of bands at 220–240 kDa, ty

  20. Corrosion and mechanical properties of hot-extruded AZ31 magnesium alloys

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    AZ31 magnesium alloys were hot-extruded at 573 K and 623 K with extrusion ratio (λ) of 20, 35 and 50. The corrosion and mechanical behavior of hot-extruded AZ31 were studied by galvanic tests and tensile tests. The microstructures of the studied AZ31 alloys were also investigated with optical microscope. The results show that, compared with the as-cast AZ31 alloy, the corrosion potentials of all hot-extruded AZ31 alloys are increased by 60 mV. Moreover, at the extrusion temperature of 623 K, the galvanic current of AZ31 alloy decreases with increasing extrusion and the galvanic corrosion resistance is increased by 10% with the extrusion ratio of 50. In addition, the tensile strength and elongation of the extruded alloys are significantly enhanced by about 20% and 140%, respectively. The improvement of corrosion resistance and obvious increasing of mechanical properties of AZ31 alloys by hot-extrusion are ascribed to grain refinement and microstructural modification together with the homogeneous distribution of intermetallie phases throughout the matrix.

  1. Corrosion resistance of biodegradable polymeric layer-by-layer coatings on magnesium alloy AZ31

    Science.gov (United States)

    Cui, Lan-Yue; Zeng, Rong-Chang; Zhu, Xiao-Xiao; Pang, Ting-Ting; Li, Shuo-Qi; Zhang, Fen

    2016-06-01

    Biocompatible polyelectrolyte multilayers (PEMs) and polysiloxane hybrid coatings were prepared to improve the corrosion resistance of biodegradable Mg alloy AZ31. The PEMs, which contained alternating poly(sodium 4-styrenesulfonate) (PSS) and poly(allylamine hydrochloride) (PAH), were first self-assembled on the surface of the AZ31 alloy substrate via electrostatic interactions, designated as (PAH/PSS)5/AZ31. Then, the (PAH/PSS)5/AZ31 samples were dipped into a methyltrimethoxysilane (MTMS) solution to fabricate the PMTMS films, designated as PMTMS/(PAH/PSS)5/AZ31. The surface morphologies, microstructures and chemical compositions of the films were investigated by FE-SEM, FTIR, XRD and XPS. Potentiodynamic polarization, electrochemical impedance spectroscopy and hydrogen evolution measurements demonstrated that the PMTMS/(PAH/PSS)5/AZ31 composite film significantly enhanced the corrosion resistance of the AZ31 alloy in Hank's balanced salt solution (HBSS). The PAH and PSS films effectively improved the deposition of Ca-P compounds including Ca3(PO4)2 and hydroxyapatite (HA). Moreover, the corrosion mechanism of the composite coating was discussed. These coatings could be an alternative candidate coating for biodegradable Mg alloys.

  2. Diagnóstico molecular de enfermedades sistémicas de la caña de azúcar en la Argentina: ajuste metodológico y aplicaciones Molecular diagnosis of sistemic sugarcane diseases in Argentina: methodology adjustment and applications

    Directory of Open Access Journals (Sweden)

    María P. Filippone

    Full Text Available Las enfermedades sistémicas representan uno de los principales factores que afectan la producción de caña de azúcar. El conocimiento del estado fitosanitario del cultivo y la identificación correcta de los fitopatógenos son claves para reducir las pérdidas por enfermedades. En este sentido, es fundamental contar con técnicas de diagnóstico sensibles, rápidas y fáciles de ejecutar, para realizar un diagnóstico preciso y precoz. A partir del año 2005, en la Estación Exper imental Agroindustrial Obispo Colombres se incorporó el diagnóstico molecular basado en la reacción en cadena de la polimerasa, para la detección específica de cuatro enfermedades sistémicas de la caña de azúcar: raquitismo de la caña soca (Leifsonia xyli sp. xyli, escaldadura de la hoja (Xanthomonas albilineans, mosaico de la caña de azúcar (Sugarcane mosaic virus, ScMV y síndrome de la hoja amarilla (Sugarcane yellow leaf virus, ScYLV. En este trabajo, se presenta la optimización metodológica del diagnóstico molecular y se compara su eficiencia con la de la técnica inmunoquímica ELISA. El método molecular mostró mayor sensibilidad para las enfermedades evaluadas, tanto bacterianas como virales. El establecimiento del diagnóstico molecular constituye un avance tecnológico de gran importancia para la industria azucarera regional, ya que no solo ayudará a disminuir la incidencia de dichas enfermedades, sino que también evitará el ingreso de otras nuevas al introducir germoplasma de caña de azúcar desde otras regiones.Systemic diseases represent one of the main factors affecting sugarcane production. The knowledge of crop sanitary conditions and the correct identification of phytopathogens are key factors to reduce losses caused by them. To diagnose diseases as early as possible is crucial, so techniques that are sensitive, fast, accurate and easy to use are essential. Since 2005, molecular diagnosis based on polymerase chain reaction has

  3. Conformal AZ5214-E resist deposition on patterned (1 0 0) InP substrates

    Science.gov (United States)

    Eliás, P.; Gregusová, D.; Martaus, J.; Kostic, I.

    2006-02-01

    A draping technique was studied to deposit thin, visco-elastic AZ5214-E resist layers from a water surface over planar and patterned substrates. A visco-elastic AZ5214-E layer forms on the water surface when a drop of AZ5214-E makes contact with it. The drop spreads out within a fraction of a second because of a large positive difference in surface tension between water and AZ5214-E. The spreading mechanism lies in the ability of PGMEA (AZ5214-E liquid constituent) to form hydrogen bonds with water. We brought AZ5214-E drops to make contact with water at 20 ± 0.1 °C via adhesive forces to form AZ5214-E layers on the water surface of (1) circular and (2) square shapes. In case (1), the layers, formed from drops of V = 3 µl, had thickness t ap c sdot 4V/πΦ-2 for Φ c sdot 4V/πΦ-2 for larger Φ. In case (2), the layers had t ap a + bV for V between 7 and 12 µl on square-shaped water surfaces of constant area A = 34.5 mm × 34.5 mm. All layers exhibited microscopic waviness with an average thickness uniformity u ~ 91%, and submicron waviness with a root-mean-square roughness σ ~ 12 nm and a lateral correlation length ξ ~ 32 µm. AZ5214-E sheets coated conformally high mesa objects with sharp convex and concave edges: 61 µm high ridges confined to ~35°-inclined facets and 9 µm high ridges confined to negatively sloped facets. The draping technique can be used to deposit conformal AZ5214-E layers over non-planar substrates for non-planar device processing.

  4. Phonon effects on the double mass differences in magic nuclei

    Science.gov (United States)

    Saperstein, E. E.; Baldo, M.; Gnezdilov, N. V.; Tolokonnikov, S. V.

    2016-03-01

    Odd-even double mass differences (DMDs) of magic nuclei are found within an approach starting from the free N N interaction, accounting for particle-phonon coupling (PC) effects. We consider three PC effects: the phonon-induced effective interaction, the renormalization of the "ends" due to the pole PC contribution to the nucleon mass operator, and the change of the single-particle energies. The perturbation theory in gL2, where gL is the vertex of the creation of the L -multipole phonon, is used for PC calculations. PC corrections to single-particle energies are found with an approximate accounting for the tadpole diagram. Results for magic Ca,4840, Ni,7856, Sn,132100, and 208Pb nuclei are presented. For the lighter part of this set of nuclei, from 40Ca to 56Ni, the cases divide approximately in half, between those where the PC corrections to DMD values are in good agreement with the data and the ones with the opposite result. In the major part of the cases of worsening description of DMD, a poor applicability of the perturbation theory for the induced interaction is the most probable reason of the phenomenon. For intermediate nuclei, 78Ni and 100Sn, there are no sufficiently accurate data on masses of nuclei necessary for finding DMD values. Finally, for heavier nuclei, 132Sn and 208Pb, PC corrections always result in better agreement with experiment.

  5. commodity: el caso del mercado internacional del azúcar

    Directory of Open Access Journals (Sweden)

    Julio César Alonso

    2013-01-01

    Full Text Available Este trabajo estudia el comportamiento estacional de los precios internacionales del azúcar transados en Nueva York y Londres. Para este caso, empleando pruebas de raíces estacionales y una muestra mensual desde enero de 1989 hasta diciembre de 2010, se encuentra la existencia de un comportamiento estacional estocástico no estacionario. Dicha conducta implica que un “verano” se puede convertir en un “invierno”, resultado que no había sido documentado previamente en estos mercados. Por otro lado, empleando dicho hallazgo, los resultados muestran que es posible construir un modelo autorregresivo de media móvil que se comporta relativamente mejor al pronosticar el precio frente a un modelo que no tiene en cuenta dicho tipo de estacionalidad.

  6. Isovector excitations of N ≠ Z nuclei

    International Nuclear Information System (INIS)

    We show that the method based on the tensor coupling of an appropriate family of isovector excitation operators to the parent isospin multiplet can be used, to advantage, for the correct treatment of the isospin degree of freedom in non isoscalar nuclei. This method is applicable to any isovector excitation operator and for parent states which need not to be of the closed subshells type. As an illustration we apply it to the study of the Gamow-Teller transition strength in 90Zr. (author)

  7. Propagation of heavy cosmic-ray nuclei

    International Nuclear Information System (INIS)

    Techniques for modeling the propagation of heavy cosmic-ray nuclei, and the required atomic and nuclear data, are assembled in this paper. Emphasis is on understanding nuclear composition in the charge range 3< Z<83. Details of the application of ''matrix methods'' above a few hundred meV per nucleon, a new treatment of electron capture decay, and a new table of cosmic-ray-stable isotopes are presented. Computation of nuclear fragmentation cross sections, stopping power, and electron stripping and attachment are briefly reviewed

  8. Miről szól az input-output modell?

    OpenAIRE

    Augusztinovics, Mária

    1996-01-01

    Három kérdésre keressük a választ: 1. Miért volt az input-output a legünnepeltebb kvantitatív makrogazdasági modell az 1950-es és 1960-as években? 2. Miért gondol- ják sokan, hogy mára elavulttá vált? 3. Mi az input-output modell lényege, ami soha nem fog elavulni?

  9. Bioetanol de la caña de azúcar

    OpenAIRE

    N. Aguilar-Rivera

    2007-01-01

    La búsqueda de la viabilidad y desarrollo de la agroindustria de la caña de azúcar es ya una política imperativa. La producción de caña y azúcar constituyen la principal agroindustria del país, con presencia en 57 ingenios azucareros, localizados en 15 estados de la república. Sin embargo, la actual ineficiencia productiva, altos costos y otras causas como la entrada de jarabe de maíz de alta fructosa (HFCS) de menor costo han desplazado el consumo interno de azúcar...

  10. Project W-211 Initial Tank Retrieval Systems (ITRS) Description of Operations for 241-AZ-102

    International Nuclear Information System (INIS)

    The primary purpose of the Initial Tank Retrieval Systems (ITRS) is to provide systems for retrieval of radioactive wastes stored in underground double-shell tanks (DSTs) for transfer to alternate storage, evaporation, pretreatment or treatment, while concurrently reducing risks associated with safety watch list and other DSTs. This Description of Operation (DOO) defines the control philosophy for the waste retrieval system for Tank 241-AZ-102 (AZ-102). This DOO provides a basis for the detailed design of the Project W-211 Retrieval Control System (RCS) for AZ-102 and also establishes test criteria for the RCS

  11. Influence of neodymium on high cycle fatigue behavior of die cast AZ91D magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    杨友; 李雪松

    2010-01-01

    High cycle fatigue behavior of die cast AZ91D magnesium alloy with different Nd contents was investigated.Axial mechanical fatigue tests were conducted at the stress ratio R=0.1 and the fatigue strength was evaluated using up-to-down load method on specimens of AZ91D with different Nd contents.The results showed that the grain of AZ91D alloy was refined,the size and amount of β-Mg17Al12 phase decreased and distributed uniformly with increasing Nd content.At the number of cycles to failure,Nf=107,the fatigue...

  12. Simulation of Magnesium Alloy AZ91D Microstructure Using Modified Cellular Automaton Method

    Institute of Scientific and Technical Information of China (English)

    HUO Liang; LI Bin; SHI Yufeng; XU Qingyan; HAN Zhiqiang; LIU Baicheng

    2009-01-01

    A two-dimensional modified cellular automaton model was developed to simulate the solidification process of magnesium alloy, The stochastic nucleation, solute redistribution, and growth anisotropy effects were taken into account in the present model. The model was used to simulate the grain size of magnesium alloy AZ91D for various cooling rates during the solidification process. To quantitatively validate the current model, metallographic expedments were carded out on specimens obtained from sand mold AZ91D step castings. The metallographic results agree well with the prediction results. The current model can be used to accurately predict the grain sizes of cast AZ91D magnesium alloy.

  13. A MANGANESE OXIDE CONTAINED COATING FOR BIODEGRADABLE AZ31B MAGNESIUM ALLOY

    OpenAIRE

    TINGTING YAN; LILI TAN; DANGSHENG XIONG; BINGCHUN ZHANG; KE YANG

    2009-01-01

    A manganese oxide contained coating was prepared on biodegradable AZ31B magnesium alloy to control the degradation of AZ31B and improve its biocompatibility. Morphology, composition, and corrosion resistance of the coating were studied. The SEM observations showed that the coating was approximately 4–6 μm in thickness with net-like microcracks. The XPS analysis indicated that the coating was mainly composed of MgO, Mg(OH)2, MnO2, Mn2O3, and Mn3O4. It was found that AZ31B with such coating sho...

  14. From heavy nuclei to super-heavy nuclei

    International Nuclear Information System (INIS)

    The existence of super-heavy nuclei has been predicted nearly fifty years ago. Due to the strong coulomb repulsion, the stabilisation of these nuclei is possible only through shell effects. The reasons for this fragile stability, as well as the theoretical predictions concerning the position of the island of stability are presented in the first part of this lecture. In the second part, experiments and experimental techniques which have been used to synthesize or search for super-heavy elements are described. Spectroscopic studies performed in very heavy elements are presented in the following section. We close this lecture with techniques that are currently being developed in order to reach the superheavy island and to study the structure of very-heavy nuclei. (author)

  15. Recent Results for the Effects of Distortion in the Inter-Cluster Motion in Light Nuclei and Application to Nuclear Astrophysics

    International Nuclear Information System (INIS)

    Deuteron induced quasi-free scattering and reactions have been extensively investigated in the past few decades. This was done not only for the study of the nuclear structure and processes but also for the important astrophysical implication (Trojan Horse Method, THM). In particular the width of the neutron momentum distribution in deuteron will be studied as a function of the transferred momentum. THM applications will also be discussed because the momentum distribution of the spectator particle inside the Trojan horse nucleus is a necessary input for this method. The impact of the width variation on the extraction of the astrophysical S(E)-factor is discussed as well as the relevance of the s and d wave component in the deuteron wave function. (author)

  16. Proceedings of the 14. International Symposium on the Interaction of Fast Neutrons with Nuclei - Neutron Generators and Application - organized by the Technical University of Dresden

    International Nuclear Information System (INIS)

    The symposium was devoted to current problems of intense fast neutron sources, especially 14 MeV DT-neutron generators, and their broad spectrum of application in nuclear physics. 56 participants from 12 countries and the IAEA demonstrate the high interest on this selected topics. The submitted contributions can be divided into two general parts. The first one gives a review about the different possibilities of the technical and technological solution in development, the present status of operation and also the problems connected with the use of intense neutron sources. Various experimental arrangements for neutron spectroscopy, determination of nuclear data and theoretical aspects are the content of the second part. The participation in this meeting of designer and operators on the one hand and users of neutron sources on the other hand was a good choice and stimulated productive discussions during the conference. (author)

  17. Az egyetemek és a vállalkozások kapcsolata az átmenet idején

    OpenAIRE

    Inzelt, Annamária

    2004-01-01

    A cikk az egyetemek és a vállalkozások közötti kapcsolatok változását vizsgálja Magyarország piacgazdasági átalakulásának - az EU-tagságot megelőző - időszakában. A cikk az innovációs rendszerelmélet és a hármas csavarvonal (triple helix) modell alkalmazásával kutatja a kapcsolatok típusait és jellemzőit. Azt elemzi, hogyan mozdítja elő a kormány az egyetemek és a vállalkozások közötti kapcsolatokat, valamint hogyan viszonyulnak a vállalkozások az egyetemekhez. A kutatás fontos részét jelente...

  18. Cavitation inception from bubble nuclei.

    Science.gov (United States)

    Mørch, K A

    2015-10-01

    The tensile strength of ordinary water such as tap water or seawater is typically well below 1 bar. It is governed by cavitation nuclei in the water, not by the tensile strength of the water itself, which is extremely high. Different models of the nuclei have been suggested over the years, and experimental investigations of bubbles and cavitation inception have been presented. These results suggest that cavitation nuclei in equilibrium are gaseous voids in the water, stabilized by a skin which allows diffusion balance between gas inside the void and gas in solution in the surrounding liquid. The cavitation nuclei may be free gas bubbles in the bulk of water, or interfacial gaseous voids located on the surface of particles in the water, or on bounding walls. The tensile strength of these nuclei depends not only on the water quality but also on the pressure-time history of the water. A recent model and associated experiments throw new light on the effects of transient pressures on the tensile strength of water, which may be notably reduced or increased by such pressure changes. PMID:26442138

  19. Model of a black hole gas submitted to background gravitational field for active galaxy nuclei with application to calculating the continuous emission spectra of massless particles (Photons: neutrinos and gravitons)

    International Nuclear Information System (INIS)

    A new theoretical model for active galaxy nuclei which describes the continuous spectrum of rest massless particles (photons, neutrinos and gravitons) in the frequency range from radiofrequency to gamma ray frequency, is presented. The model consists in a black hole gas interacting with a background gravitacional field. The previously models proposed for active galaxy nuclei are exposured. Whole theoretical fundaments based on Einstein general relativity theory for defining and studying singularity properties (black holes) are also presented. (M.C.K.)

  20. Breaking of the z-signature symmetry in the Hartree-Fock-Bogoliubov formalism. Applications to the dynamics of deformed nuclei

    International Nuclear Information System (INIS)

    This work concerns the extension of the application domain of microscopic calculations in nuclear structure to phenomena breaking the z-signature symmetry. The approach followed consists in solving the many-body problem by means of the mean-field approximation using the Hartree-Fock-Bogoliubov method. By employing the Gogny nucleon-nucleon interaction, mean-field effects as well as pairing correlations are calculated in a self-consistent way. In order to simplify the iterative resolution of the associated system of non-linear equations, the remaining symmetries of the system are explicitly taken into account. In all studies made up to now, the z-signature symmetry was imposed. The solutions of the HFB problem were eigenstates of the z-signature symmetry, a symmetry related to a rotation of π around the z axis. However, many physical phenomena, as rotational bands based on individual excitations and magnetic dipole collective excitations, break this symmetry. In this work the formalism needed to take into account this symmetry breaking is developed and results are given for the two above phenomena. Theoretical rotational bands are in good agreement with experimental data. Band-heads excitation energies as well as moment of inertia are well reproduced. Concerning magnetic dipole excitations, we show that the low-lying l+ states experimentally observed, are not collective scissor excitations, the latter being found at high excitation energy. An interpretation in terms of rather non-collective hexadecapole excitations coupled to individual excitations is proposed. (author)

  1. Hot nuclei study: Is there a limit for the excitation energy that a nucleus can endure. Application to 40Ca + 27Al system at 25 and 35 MeV/u

    International Nuclear Information System (INIS)

    Hot nuclei produced in the 40Ca+27Al reaction have been studied at 25 and 35 MeV/u. In a first part, we remind the experimental context which brings us to perform this experiment and to use the AMPHORA multidetector. AMPHORA's efficiency for the most violent collisions has then been verified. The hot nuclei study requires the definition of a criterion to select central collisions. We established that a light particles multiplicity greater or equal to 9 selected a special class of these collisions. We exhibit the experimental results deduced from these hot nuclei study: source velocity, excitation energy, temperature. After comparison with an evaporation code, we deduce excitation energies per nucleon of 6 MeV/u at 25 MeV/u and 7.5 MeV/u at 35 MeV/u. Despite the significant increase of hot nuclei excitation energies, we do not observe a strong evolution for the associated charge distributions and heavy fragments multiplicities. Rare events where 75% of total charge are carried away by light particles have then been studied. They are associated with very hot nuclei and we call them vaporization events. The comparison between experimental results and those of a statistical evaporation code confirms that we selected nuclei with high excitation energy. The agreement is generally good except for charge distributions evolution depending on the source's excitation energy. However, these problems should not challenge the statistical nature of evaporation mechanisms

  2. Dynamic behaviors of a Ca–P coated AZ31B magnesium alloy during in vitro and in vivo degradations

    International Nuclear Information System (INIS)

    Surface modification can be an effective way to control the biodegradation behavior of magnesium alloys and even improve their biological properties. Much attention has been paid to the initial protection ability and biological properties of magnesium alloys coating. In this work, the dynamic behaviors of a Ca–P coated AZ31B magnesium alloy during the degradations in vitro and in vivo, including hemolysis, mechanical loading capability and implantation in animals, were investigated. The hemolytic rates of the alloy with and without coating were all declined to be lower than 5% after more than 20 days immersion in PBS, though an increase happened to the alloy at the early immersion of 3–7 days. Reduction of the mechanical loading capacity was gradually evolved for the coated alloy and the peak load retention of 85% was still maintained after 120 days degradation. The in vivo implantation indicated that the Ca–P coated AZ31B alloy showed a more suitable time dependent degradation behavior which was favorable for growth of the new tissue and the healing dynamics of bones, making it a promising choice for medical application.

  3. Photodissociation of neutron deficient nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Sonnabend, K.; Babilon, M.; Hasper, J.; Mueller, S.; Zarza, M.; Zilges, A. [TU Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany)

    2006-03-15

    The knowledge of the cross sections for photodissociation reactions like e.g. ({gamma}, n) of neutron deficient nuclei is of crucial interest for network calculations predicting the abundances of the so-called p nuclei. However, only single cross sections have been measured up to now, i.e., one has to rely nearly fully on theoretical predictions. While the cross sections of stable isotopes are accessible by experiments using real photons, the bulk of the involved reactions starts from unstable nuclei. Coulomb dissociation (CD) experiments in inverse kinematics might be a key to expand the experimental database for p-process network calculations. The approach to test the accuracy of the CD method is explained. (orig.)

  4. Photodissociation of neutron deficient nuclei

    Science.gov (United States)

    Sonnabend, K.; Babilon, M.; Hasper, J.; Müller, S.; Zarza, M.; Zilges, A.

    2006-03-01

    The knowledge of the cross sections for photodissociation reactions like e.g. (γ, n) of neutron deficient nuclei is of crucial interest for network calculations predicting the abundances of the so-called p nuclei. However, only single cross sections have been measured up to now, i.e., one has to rely nearly fully on theoretical predictions. While the cross sections of stable isotopes are accessible by experiments using real photons, the bulk of the involved reactions starts from unstable nuclei. Coulomb dissociation (CD) experiments in inverse kinematics might be a key to expand the experimental database for p-process network calculations. The approach to test the accuracy of the CD method is explained.

  5. Cavitation inception from bubble nuclei

    DEFF Research Database (Denmark)

    Mørch, Knud Aage

    2015-01-01

    experimental investigations of bubbles and cavitation inception have been presented. These results suggest that cavitation nuclei in equilibrium are gaseous voids in the water, stabilized by a skin which allows diffusion balance between gas inside the void and gas in solution in the surrounding liquid. The...... cavitation nuclei may be free gas bubbles in the bulk of water, or interfacial gaseous voids located on the surface of particles in the water, or on bounding walls. The tensile strength of these nuclei depends not only on the water quality but also on the pressure-time history of the water. A recent model...... and associated experiments throw new light on the effects of transient pressures on the tensile strength of water, which may be notably reduced or increased by such pressure changes....

  6. Microscopic description of light unstable nuclei with the stochastic variational method

    CERN Document Server

    Varga, K; Arai, K; Ogawa, Y

    1996-01-01

    The structure of the light proton and neutron rich nuclei is studied in a microscopic multicluster model using the stochastic variational method. This approach enables us to describe the weakly bound nature of these nuclei in a consistent way. Applications for various nuclei ^{6-9}Li, ^7Be, ^8B, ^9C, ^{9-10}Be, ^{9-10}B presented. The paper discusses the relation of this model to other models as well as the possible extension for p and sd shell nuclei.

  7. EnviroAtlas -Phoenix, AZ- One Meter Resolution Urban Land Cover Data (2010) Web Service

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas web service supports research and online mapping activities related to EnviroAtlas (https://www.epa.gov/enviroatlas). The EnviroAtlas Phoenix, AZ...

  8. EnviroAtlas - Phoenix, AZ - One Meter Resolution Urban Land Cover Data (2010)

    Data.gov (United States)

    U.S. Environmental Protection Agency — The EnviroAtlas Phoenix, AZ land cover (LC) data and map were generated from USDA NAIP (National Agricultural Imagery Program) four band (red, green, blue and...

  9. Microstructure and properties of AZ80 magnesium alloy prepared by hot extrusion from recycled machined chips

    Institute of Scientific and Technical Information of China (English)

    刘英; 李元元; 张大童; 倪东惠; 陈维平

    2002-01-01

    AZ80 magnesium alloy was prepared by hot extrusion of recycled machined chips and its microstructure and mechanical properties were investigated. Hot pressing was employed to prepare extrusion billets of AZ80 chips, then the billets were hot extruded at 623K with an extrusion ratio of 25∶ 1. The extruded rods show a high ultimate tensile strength of 285MPa and a high elongation of 6%. Due to grain refinement by extrusion, mechanical properties of the extruded rods are much higher than those of as-cast AZ80 alloy. Process technique and chips densification mechanism were also studied. Results show that hot extrusion is an efficient method for AZ80 alloy chips recycling.

  10. Effect of Carbon Nanotube on High-Temperature Formability of AZ31 Magnesium Alloy

    Science.gov (United States)

    Hassan, S. Fida; Paramsothy, M.; Gasem, Z. M.; Patel, F.; Gupta, M.

    2014-08-01

    Room-temperature tensile properties of AZ31 alloy have significantly been improved when reinforced with carbon nanotube via ingot metallurgy process. However, high-temperature (up to 250 °C) elongation-to-failure tensile test of the developed nanocomposite revealed a considerable softening in the AZ31 alloy matrix accompanied by an incredible ductility increment (up to 132%). Microstructural characterization of the fractured samples revealed that the dynamic recrystallization process has induced a complete recrystallization in the AZ31 alloy at a lower temperature (150 °C) followed by substantial grain growth at a higher temperature used in this study. Fractography on the fractured surfaces revealed that the room-temperature mixed brittle-ductile modes of fracture behavior of AZ31 alloy have transformed into a complete ductile mode of fracture at high temperature.

  11. Effects of Ca addition on microstructure and properties of AZ63 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    钱宝光; 耿浩然; 陶珍东; 赵鹏; 田宪法

    2004-01-01

    Effects of Ca addition on the microstructure and viscosity as well as electrochemical properties of casting AZ63 magnesium alloy were studied. Testing results show that the viscosity value increases with the increase of calcium content, especially at the higher temperature, and there exists such a relation between the ignition temperature and viscosity of magnesium alloy: when the melt viscosity increases, the ignition temperature increases too. The microstructure of AZ63 magnesium alloy is first refined and then coarsened with the increase of Ca addition. By the addition of 0.15% Ca, AZ63 alloy has more negative open-circuit potential(1. 624 5V), bigger anode efficiency (55.65%) and lower corrosion rate(0.214g/(m2·h).AZ63 allo6y containing some Ca content is a high driving-potential and high-efficiency sacrificial anodes material.

  12. Wear resistance of ceramic coating on AZ91 magnesium alloy by micro-arc oxidation

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hui; LIU Zheng; CHEN Li-jia; CHEN Ji; HAN Zhong

    2006-01-01

    The ceramic coating formed on AZ91 magnesium alloy by micro-arc oxidation (MAO) was characterized. The results show that the ceramic coating(3.4-23 μm in thickness)on the surface of AZ91 alloy was attained under different micro-arc oxidation treatment conditions, which consist mainly of MgO, Mg2SiO4 and MgSiO3 phases. Nano-hardness in a cross-sectional specimen was determined by nano-indentation experiment. The MAO coatings exhibit higher hardness than the substrate. Dry sliding wear tests for the MAO coatings and AZ91 alloy were also carried out using an oscillating friction and wear tester in a ball-on-disc contact configuration. The wear resistance of the MAO coatings is improved respectively under different treatment time as a result of different structures of ceramic coatings formed on AZ91 alloy.

  13. EnviroAtlas - Phoenix, AZ - BenMAP Results by Block Group

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset demonstrates the effect of changes in pollution concentration on local populations in 2,434 block groups in Phoenix, AZ. The US EPA's...

  14. Draft Genome Sequence of Lysobacter capsici AZ78, a Bacterium Antagonistic to Plant-Pathogenic Oomycetes.

    Science.gov (United States)

    Puopolo, Gerardo; Sonego, Paolo; Engelen, Kristof; Pertot, Ilaria

    2014-01-01

    Lysobacter capsici AZ78, isolated from tobacco rhizosphere, effectively controls Phytophthora infestans and Plasmopara viticola on tomato and grapevine plants, respectively. We report the first draft genome sequence of the L. capsici species. PMID:24762937

  15. Spontaneous fission of superheavy nuclei

    Indian Academy of Sciences (India)

    R A Gherghescu; D N Poenaru

    2015-09-01

    The macroscopic–microscopic method is extended to calculate the deformation energy and penetrability for binary nuclear configurations typical for fission processes. The deformed two-centre shell model is used to obtain single-particle energy levels for the transition region of two partially overlapped daughter and emitted fragment nuclei. The macroscopic part is obtained using the Yukawa-plus-exponential potential. The microscopic shell and pairing corrections are obtained using the Strutinsky and BCS approaches and the cranking formulae yield the inertia tensor. Finally, the WKB method is used to calculate penetrabilities and spontaneous fission half-lives. Calculations are performed for the decay of 282,292120 nuclei.

  16. International Symposium on Exotic Nuclei

    CERN Document Server

    Sobolev, Yu G; EXON-2014

    2015-01-01

    The production and the properties of nuclei in extreme conditions, such as high isospin, temperature, angular momenta, large deformations etc., have become the subject of detailed investigations in all scientific centers. The main topics discussed at the Symposium were: Synthesis and Properties of Exotic Nuclei; Superheavy Elements; Rare Processes, Nuclear Reactions, Fission and Decays; Experimental Facilities and Scientific Projects. This book provides a comprehensive overview of the newest results of the investigations in the main scientific centers such as GSI (Darmstadt, Germany), GANIL (Caen, France), RIKEN (Wako-shi, Japan), MSU (Michigan, USA), and JINR (Dubna, Russia).

  17. Coulomb displacement energies in nuclei

    International Nuclear Information System (INIS)

    In the present work the positions of the isobaric analog resonances (IAR) are calculated using the HF-TDA theory with a complete proton particle-neutron hole basis. The important feature of this approach is the fact that the HF potential and the particle-hole interaction used in the TDA are derived from the same two-body interactions. In this theroy all the higher order effects are taken into account in one consistent framework. The calculations are performed for several N > Z, closed shell nuclei. For these nuclei good agreement between the experimental and theoretical excitation energies of the IAR is obtained. (orig.)

  18. PDFs from nucleons to nuclei

    CERN Document Server

    Accardi, Alberto

    2016-01-01

    I review recent progress in the extraction of unpolarized parton distributions in the proton and in nuclei from a unified point of view that highlights how the interplay between high energy particle physics and lower energy nuclear physics can be of mutual benefit to either field. Areas of overlap range from the search for physics beyond the standard model at the LHC, to the study of the non perturbative structure of nucleons and the emergence of nuclei from quark and gluon degrees of freedom, to the interaction of colored probes in a cold nuclear medium.

  19. Nuclei, hadrons, and elementary particles

    International Nuclear Information System (INIS)

    This book is a short introduction to the physics of the nuclei, hadrons, and elementary particles for students of physics. Important facts and model imaginations on the structure, the decay, and the scattering of nuclei, the 'zoology' of the hadrons and basic facts of hadronic scattering processes, a short introduction to quantum electrodynamics and quantum chromodynamics and the most important processes of lepton and parton physics, as well as the current-current approach of weak interactions and the Glashow-Weinberg-Salam theory are presented. (orig.) With 153 figs., 10 tabs

  20. Neutron scattering on deformed nuclei

    International Nuclear Information System (INIS)

    Measurements of neutron elastic and inelastic differential cross sections around 14 MeV for 9Be, C, 181Ta, 232Th, 238U and 239Pu have been analyzed using a coupled channel (CC) formalism for deformed nuclei and phenomenological global optical model potentials (OMP). For the actinide targets these results are compared with the predictions of a semi-microscopic calculation using Jeukenne, Lejeune and Mahaux (JLM) microscopic OMP and a deformed ground state nuclear density. The overall agreement between calculations and the measurements is reasonable good even for the very light nuclei, where the quality of the fits is better than those obtained with spherical OMP

  1. Octupole shapes in heavy nuclei

    International Nuclear Information System (INIS)

    Theoretical calculations and measurements show the presence of strong octupole correlations in thecyround states and low-lying states of odd-mass and odd-odd nuclei in the RaPa region. Evidence for octupole correlations is provided by the observation of parity doublets and reductions in M1 matrix elements, decoupling parameters, and Coriolis matrix elements Involving high-j states. Enhancement of E1 transition rates has also been observed for some of the octupole deformed nuclei. The most convincing argument for octupole deformation is provided by the similarities of the reduced alpha decay rates to the two members of parity doublets

  2. Microstructure and corrosion resistance of Ce–V conversion coating on AZ31 magnesium alloy

    International Nuclear Information System (INIS)

    Highlights: • Through simple chemical conversion process, a Ce–V conversion coating is prepared on AZ31 magnesium alloy. The coating (∼2 μm thick) has a duplex structure and is composed of Mg, Al, Ce, V and O in the outer layer and Mg, Al, V, F and O in the inner layer. • The Ce–V conversion coating can increase the Ecorr by 157 mV and decrease the icorr by 80 times compared to AZ31 magnesium alloy substrate. Moreover, the performance of the Ce–V conversion coating excels the chromate conversion coating on AZ31 magnesium alloy. • The EIS results of Ce–V conversion coating indicate an increase of 10× in the corrosion resistance and a delay in the corrosion process kinetics compared to uncoated AZ31 magnesium alloy in 3.5 wt.% NaCl solution. • The ball cratering is a simple and effective technique of thickness measurement for chemical conversion coating. - Abstract: A Ce–V conversion coating was developed to improve the corrosion resistance of AZ31 magnesium alloy. Scanning electronic microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectrometer (XPS), grazing incidence X-ray diffraction (GIXRD) and the ball cratering test were adopted to study the morphology, chemical composition, structure and thickness of the coating. The coating has duplex structure with network and its thickness is about 2 μm. The coating contains high contents of Ce and V, which exhibits amorphous structure. Potentiodynamic polarization shows the coating can increase the corrosion potential and reduce the corrosion current density of AZ31 magnesium alloy. Moreover, the electrochemical impedance spectra exhibit the coating significantly improves the corrosion resistance of AZ31 magnesium alloy. Results indicate that the Ce–V conversion coating can provide effective protection to AZ31 magnesium alloy

  3. Influence of boron addition on the grain refinement and mechanical properties of AZ91 Mg alloy

    International Nuclear Information System (INIS)

    This article reports the effect of boron addition on the grain refinement efficiency and mechanical properties of AZ91 magnesium alloy. The results show that the addition of boron in the form of Al-4B master alloy, significantly refines the grain size of AZ91 alloy. This refinement is due to the presence of AlB2 particles, which act as potential nucleants for Mg grains. Improved mechanical properties are obtained with the addition of boron due to the finer grains.

  4. Acceptance Test Report for the 241-AZ-101 Ultrasonic Interface Level Analyzer

    International Nuclear Information System (INIS)

    This document comprises the Acceptance Test Report for the 241-AZ-101 Ultrasonic Interface Level Analyzer. This document presents the results of Acceptance Testing of the 241-AZ-101 Ultrasonic Interface Level Analyzers (URSILLAs). Testing of the URSILLAs was performed in accordance with ATP-260-001, ''URSILLA Pre-installation Acceptance Test Procedure''. The objective of the testing was to verify that all equipment and components function in accordance with design specifications and original equipment manufacturer's specifications

  5. Numerical simulation of temperature field of AZ91D magnesium alloy during equal channel angular extrusion

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The temperature field of AZ91D magnesium alloy extruded by equal channel angular extrusion(ECAE) has been simulated using finite element method(FEM).A series of tests were designed to obtain the simulation parameters:flow stress of AZ91D,friction factor and heat transfer coefficient.The simulated temperature agrees well with the measured one.The evolution of temperature and influencing factor was discussed in details.Furthermore,the extrusion pressure of ECAE was analyzed.

  6. Repeatable and reproducible methodology of the AZ91 alloy structure evaluation

    Directory of Open Access Journals (Sweden)

    J. Adamiec

    2007-04-01

    Full Text Available The objective of the research conducted was to develop a comprehensive procedure for a quantitative evaluation of magnesium casting alloy’s (AZ91 microstructure. The procedure encompasses: a methodology of metallographic specimens preparation, microstructure detection methods, selection of image acquisition methods, image analysis methodology and adjustment of morphological and stereological parameters to the quantitative description of volume fraction of phases and structural components of the AZ91.

  7. AZ91D半固态坯料的等温压缩变形研究%Isothermal Compression Deformation of AZ91D Semisolid Billets

    Institute of Scientific and Technical Information of China (English)

    曹富荣; 管仁国; 邢振环

    2011-01-01

    AZ91D semisolid billets were prepared by a self-designed wavelike sloping plate device. Mechanical behavior and microstructure evolution of isothermal compression deformation in AZ91D semisolid billets have been studied using a Gleeble1500 thermal simulation machine and optical microscopy. When deformation temperature was constant, true stress increased with increasing strain rate; when strain rate was constant, true stress decreased with increasing deformation temperature. The deformation mechanisms of AZ91D alloy were quasi-elastic deformation during isothermal compression and phase interface sliding under thermal activation. The microstructures of isothermal compression of AZ91D semisolid billets consist of globular and near-globular grains that are caused by the round-grinding of a-Mg grains under shear stress and Ostwald ripening under surface tension.%采用自行设计的波浪型倾斜板装置制备了AZ91D半固态坯料.利用Gleeblel500热模拟实验机和光学显微镜对AZ91D半固态坯料等温压缩变形力学行为和组织演变进行了研究.结果表明:在变形温度相同的情况下,随应变速率的增加,真应力增大;随变形速率的降低,真应力减小;在应变速率相同的情况下,随变形温度的增加,真应力减小.随变形温度的降低,真应力增大.AZ91D半固态坯料等温压缩的变形机制为准弹性变形机制和热激活条件下的相界面滑动变形机制.AZ91D半固态坯料等温压缩变形的组织为球形和近球形晶粒,剪切应力作用下的α-Mg晶粒磨圆和表面张力作用下的Ostwald熟化是获得球形和近球形组织的原因.

  8. Native Oxide Films on AZ31 and AZ61 Commercial Magnesium Alloys ─ Corrosion Behaviour, Effect on Isothermal Oxidation and Sol─gel Thin Film Formation

    OpenAIRE

    Feliu, Sebastían; Barranco, V.; Llorente, Irene; García-Galván, Federico R.; Jimenez Morales, Antonia; Galván Sierra, Juan Carlos; El Hadad, Amir

    2015-01-01

    The authors present a review of their recent research work in an endeavour to interpret the influence of native oxide films on the corrosion behaviour of commercial AZ31 and AZ61 magnesium alloys or on the oxidation kinetics in air at 200°C. The tendency of some of these thin films to be sufficiently protective in mild or weak corrosive environments is examined. For obtaining oxide films with different protective properties, some of the specimens are tested with the surface in the as-received...

  9. Electrochemical corrosion behavior of AZ91D alloy in ethylene glycol

    International Nuclear Information System (INIS)

    The effect of concentration on the corrosion behavior of Mg-based alloy AZ91D was investigated in ethylene glycol-water solutions using electrochemical techniques i.e. potentiodynamic polarization, electrochemical impedance measurements (EIS) and surface examination via scanning electron microscope (SEM) technique. This can provide a basis for developing new coolants for magnesium alloy engine blocks. Corrosion behavior of AZ91D alloy by coolant is important in the automotive industry. It was found that the corrosion rate of AZ91D alloy decreased with increasing concentration of ethylene glycol. For AZ91D alloy in chloride >0.05 M or fluoride 0.05 M for fluoride containing ethylene glycol solution, some inhibition effect has been observed. The corrosion of AZ91D alloy in the blank can be effectively inhibited by addition of 0.05 mM paracetamol that reacts with AZ91D alloy and forms a protective film on the surface at this concentration as confirmed by surface examination.

  10. Effect of rare earth elements on high cycle fatigue behavior of AZ91 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Mokhtarishirazabad, M., E-mail: mehdi-mokhtari@hotmail.com [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Boutorabi, S.M.A. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Azadi, M.; Nikravan, M. [Irankhodro Powertrain Company (IPCO), Tehran (Iran, Islamic Republic of)

    2013-12-10

    This article investigates effects of adding rare earth elements (RE) into a magnesium–aluminum–zinc alloy (the AZ91 alloy) on its high cycle fatigue (HCF) behavior. For this purpose, AZ91 and AZ91+1% RE (AZE911) alloys were gravity casted in a metallic die. RE elements were added to the AZ91 alloy in the form of mischmetals. Microscopic evaluations with the scanning electron microscopy (SEM) and mechanical tests include tensile, hardness and HCF behaviors, were performed on prepared samples. Rotary bending fatigue tests were carried out at a stress ratio (R) of −1 and a frequency of 125 Hz, at the room temperature, in the air. The microscopic investigation demonstrates that the addition of 1% RE elements leads to the formation of Al{sub 11}RE{sub 3} intermetallic particles which is associated to the reduction of β-(Mg{sub 17}Al{sub 12}) phases. Results of mechanical experiments suggest a negligible effect of adding 1% RE elements on mechanical properties of the AZ91 alloy. Curves of stress-life (S–N) shows an increase in the fatigue strength at 10{sup 5} cycles, from 100±10 MPa to 135±10 MPa, when RE elements were added to the AZ91 alloy.

  11. Microstructure and corrosion behavior of electrodeposited nano-crystalline nickel coating on AZ91 Mg alloy

    International Nuclear Information System (INIS)

    Highlights: • Activation, zincating, and Cu electrodeposition were used as pretreatment processes for electrodeposition of nickel coatings. • Nano-crystalline nickel coatings were successfully electrodeposited onto the AZ91 Mg alloys. • Effect of nickel electrodeposited coating on the corrosion resistance of AZ91 Mg alloy has been studied. - Abstract: In order to enhance the corrosion resistance, nickel coating was electrodeposited onto AZ91 Mg alloy. Activation, zincating, and Cu electrodeposition used as pretreatment processes for better adhesion and corrosion performance of the nickel over layer. The corrosion properties of the AZ91 Mg alloy, nickel electroplated AZ91 Mg alloy, and pure nickel was assessed via polarization and electrochemical impedance spectroscopy (EIS) methods in 3.5 wt% NaCl solution. Moreover, the structure of the coating was investigated by means of X-ray diffraction, whereas specimen’s morphology and elemental composition were analyzed using scanning electron microscope (SEM) equipped with energy dispersive spectrometer (EDS). Measurements revealed that the coating has a nano-crystalline structure with the grain size of 95 nm. Corrosion results showed superior corrosion resistance for the coated AZ91 Mg alloy as the corrosion current density decreased from 2.5 × 10−4 A cm−2, for the uncoated sample, to 1.5 × 10−5 A cm−2, for coated specimen and the corrosion potential increased from −1.55 V to −0.98 V (vs. Ag/AgCl) at the same condition

  12. Texture Evolution of Single-Pass Hot-Rolled 5052/AZ31/5052 Clad Sheets

    Science.gov (United States)

    Nie, Huihui; Liang, Wei; Yang, Fuqian; Zheng, Liuwei; Li, Xianrong; Fan, Haiwei

    2016-06-01

    Three-layered 5052/AZ31/5052 clad sheets with maximum rolling reductions of 33% and 48% were prepared, using single-pass hot rolling followed by thermal annealing at 200°C for 1 h. The evolutions of microstructures and textures were analyzed. The experimental results show that the AZ31 layer exhibited a typical deformation microstructure with rolling-induced twins. The AZ31 layer with the 33% rolling reduction possessed a texture with the basal pole tilting about 35° away from normal direction to transverse direction and the majority of twins consists of {10 bar{1} 1}-{10 bar{1} 2} double twins and {10 bar{1} 2} tensile twins. The AZ31 layer with the 48% rolling reduction possessed a typical basal texture because {10 bar{1} 1} compression twins were activated by c-axis strain to compete with the tensile twins. No intermetallics were observed after annealing, and recrystallization occurred preferentially at the interface between AZ31 and 5052. The typical rolling texture of the 5052 layer disappeared, and the stable {001} rotation cube component was dominant. The tensile test of the rolled three-layered 5052/AZ31/5052 clad sheets was performed. The tensile experimental results show that the annealed clad sheets with 33% rolling reduction and smaller degree of recrystallization have the largest elongation of 22.5% and larger ultimate tensile strength (UTS) than the annealed clad sheets with 48% rolling reduction.

  13. Electrochemical corrosion behavior of AZ91D alloy in ethylene glycol

    Energy Technology Data Exchange (ETDEWEB)

    Fekry, A.M. [Chemistry Department, Faculty of Science, Cairo University, Giza 12613 (Egypt)], E-mail: hham4@hotmail.com; Fatayerji, M.Z. [Chemistry Department, Faculty of Science, Cairo University, Giza 12613 (Egypt)

    2009-11-01

    The effect of concentration on the corrosion behavior of Mg-based alloy AZ91D was investigated in ethylene glycol-water solutions using electrochemical techniques i.e. potentiodynamic polarization, electrochemical impedance measurements (EIS) and surface examination via scanning electron microscope (SEM) technique. This can provide a basis for developing new coolants for magnesium alloy engine blocks. Corrosion behavior of AZ91D alloy by coolant is important in the automotive industry. It was found that the corrosion rate of AZ91D alloy decreased with increasing concentration of ethylene glycol. For AZ91D alloy in chloride >0.05 M or fluoride <0.05 M containing 30% ethylene glycol solution, they are more corrosive than the blank (30% ethylene glycol-70% water). However, at concentrations <0.05 for chloride or >0.05 M for fluoride containing ethylene glycol solution, some inhibition effect has been observed. The corrosion of AZ91D alloy in the blank can be effectively inhibited by addition of 0.05 mM paracetamol that reacts with AZ91D alloy and forms a protective film on the surface at this concentration as confirmed by surface examination.

  14. Symmetry Remnants in the Face of Competing Interactions in Nuclei

    CERN Document Server

    Leviatan, A

    2015-01-01

    Detailed description of nuclei necessitates model Hamiltonians which break most dynamical symmetries. Nevertheless, generalized notions of partial and quasi dynamical symmetries may still be applicable to selected subsets of states, amidst a complicated environment of other states. We examine such scenarios in the context of nuclear shape-phase transitions.

  15. Symmetry remnants in the face of competing interactions in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Leviatan, A., E-mail: ami@phys.huji.ac.il [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel); Macek, M., E-mail: michal.macek@yale.edu [Center for Theoretical Physics, Sloane Physics Laboratory, Yale University, New Haven, CT 06520-8120 (United States)

    2015-10-15

    Detailed description of nuclei necessitates model Hamiltonians which break most dynamical symmetries. Nevertheless, generalized notions of partial and quasi dynamical symmetries may still be applicable to selected subsets of states, amidst a complicated environment of other states. We examine such scenarios in the context of nuclear shape-phase transitions.

  16. Auxiliary-field quantum Monte Carlo methods in nuclei

    CERN Document Server

    Alhassid, Y

    2016-01-01

    Auxiliary-field quantum Monte Carlo methods enable the calculation of thermal and ground state properties of correlated quantum many-body systems in model spaces that are many orders of magnitude larger than those that can be treated by conventional diagonalization methods. We review recent developments and applications of these methods in nuclei using the framework of the configuration-interaction shell model.

  17. Gluons in nuclei and pions

    International Nuclear Information System (INIS)

    The possibility of connecting apparently different descriptions of quarks in nuclei has already been shown. The authors pursue the consequences of this 'duality' for flavour-singlet distributions. An interesting possibility is that nuclear pions may have unusual quark-gluon substructure. Indeed, pions in general could be relatively 'rich' in glue. (author)

  18. Magnetic shift of magic nuclei

    International Nuclear Information System (INIS)

    The shell effect of nuclei in strong magnetic fields associated with magnetars' is considered within the shell model. It is demonstrated that the magnetic field gives rise to a change of the phase in shell-oscillations of nuclear masses. The nuclear magic numbers of the iron region are shifted significantly towards smaller mass numbers. (author)

  19. Fission dynamics of hot nuclei

    Indian Academy of Sciences (India)

    Santanu Pal; Jhilam Sadhukhan

    2014-04-01

    Experimental evidence accumulated during the last two decades indicates that the fission of excited heavy nuclei involves a dissipative dynamical process. We shall briefly review the relevant dynamical model, namely the Langevin equations for fission. Statistical model predictions using the Kramers’ fission width will also be discussed.

  20. Low energy + scattering on = nuclei

    Indian Academy of Sciences (India)

    Swapan Das; Arun K Jain

    2003-11-01

    The data for the total cross-section of + scattering on various nuclei have been analysed in the Glauber multiple scattering theory. Energy-dependent +-nucleus optical potential is generated using the forward +-nucleon scattering amplitude and the nuclear density distribution. Along with this, the calculated total +-nucleus cross-sections using the effective +-nucleon cross-section inside the nucleus are also presented.

  1. Nuclear astrophysics of light nuclei

    DEFF Research Database (Denmark)

    Fynbo, Hans Otto Uldall

    2013-01-01

    A review of nuclear astrophysics of light nuclei using radioactive beams or techniques developed for radioactive beams is given. We discuss Big Bang nucleosynthesis, with special focus on the lithium problem, aspects of neutrino-physics, helium-burning and finally selected examples of studies...

  2. Generalized parton distributions of nuclei

    OpenAIRE

    Guzey, V.

    2009-01-01

    We review recent theoretical results on generalized parton distributions (GPDs) of nuclei, emphasizing the following three roles of nuclear GPDs: (i) complementarity to free proton GPDs, (ii) the enhancement of traditional nuclear effects such as nuclear binding, EMC effect, nuclear shadowing, and (iii) an access to novel nuclear effects such as medium modifications of bound nucleons.

  3. Octupole correlation effects in nuclei

    International Nuclear Information System (INIS)

    Octupole correlation effects in nuclei are discussed from the point of view of many-body wavefunctions as well as mean-field methods. The light actinides, where octupole effects are largest, are considered in detail. Comparisons of theory and experiment are made for energy splittings of parity doublets; E1 transition matrix elements and one-nucleon transfer reactions

  4. Fission Dynamics of Compound Nuclei

    OpenAIRE

    Iwata, Yoritaka; Heinz, Sophia

    2012-01-01

    Collisions between $^{248}$Cm and $^{48}$Ca are systematically investigated by time-dependent density functional calculations with evaporation prescription. Depending on the incident energy and impact parameter, fusion, deep-inelastic and quasi-fission events are expected to appear. In this paper, possible fission dynamics of compound nuclei is presented.

  5. Percolation and multifragmentation of nuclei

    International Nuclear Information System (INIS)

    A method to build the 'cold' nuclei as percolation clusters is suggested. Within the framework of definite assumptions of the character of nucleon-nucleon couplings breaking resulting from the nuclear reactions as description of the multifragmentation process in the hadron-nucleus and nucleus-nucleus reactions at high energies is obtained. 19 refs.; 6 figs

  6. Chiral Electroweak Currents in Nuclei

    CERN Document Server

    Riska, D O

    2016-01-01

    The development of the chiral dynamics based description of nuclear electroweak currents is reviewed. Gerald E. (Gerry) Brown's role in basing theoretical nuclear physics on chiral Lagrangians is emphasized. Illustrative examples of the successful description of electroweak observables of light nuclei obtained from chiral effective field theory are presented.

  7. Static multipole deformations in nuclei

    International Nuclear Information System (INIS)

    The physics of static multipole deformations in nuclei is reviewed. Nuclear static moments result from the delicate balance between the vibronic Jahn-Teller interaction (particle-vibration coupling) and the residual interaction (pairing force). Examples of various permanent nuclear deformations are discussed

  8. Surface delta interaction and properties of medium mass nuclei

    International Nuclear Information System (INIS)

    The idea of Surface Delta Interaction (SDI) is that because of Pauli principle, the interaction between nucleons is peaked near the surface of the nucleus. The delta potential is short ranged like free NN interaction. It has some interesting properties which makes it a quite 'realistic' interaction, to use. SDI gives matrix elements which are quite close to empirical matrix elements found from shell model studies. Also this interaction reproduces deformation properties quite well in complex nuclei. Comparison of SDI matrix elements with two modern interactions, namely, JUN45 and G-f5pg9 interaction has been made and report some applications to finite nuclei

  9. Rotational states in deformed nuclei: An analytic approach

    CERN Document Server

    Bentz, W; Enders, J; Richter, A; Wambach, J

    2011-01-01

    The consequences of the spontaneous breaking of rotational symmetry are investigated in a field theory model for deformed nuclei, based on simple separable interactions. The crucial role of the Ward-Takahashi identities to describe the rotational states is emphasized. We show explicitly how the rotor picture emerges from the isoscalar Goldstone modes, and how the two-rotor model emerges from the isovector scissors modes. As an application of the formalism, we discuss the M1 sum rules in deformed nuclei, and make connection to empirical information.

  10. Nuclei at extreme conditions. A relativistic study

    Energy Technology Data Exchange (ETDEWEB)

    Afanasjev, Anatoli [Mississippi State Univ., Mississippi State, MS (United States)

    2014-11-14

    The major goals of the current project were further development of covariant density functional theory (CDFT), better understanding of its features, its application to different nuclear structure and nuclear astrophysics phenomena and training of graduate and undergraduate students. The investigations have proceeded in a number of directions which are discussed in detail in the part “Accomplishments” of this report. We have studied the role of isovector and isoscalar proton-neutron pairings in rotating nuclei; based on available experimental data it was concluded that there are no evidences for the existence of isoscalar proton-neutron pairing. Generalized theoretical approach has been developed for pycnonuclear reaction rates in the crust of neutron stars and interior of white dwarfs. Using this approach, extensive database for considerable number of pycnonuclear reactions involving stable and neutron-rich light nuclei has been created; it can be used in future for the study of various nuclear burning phenomena in different environments. Time-odd mean fields and their manifestations in terminating states, non-rotating and rotating nuclei have been studied in the framework of covariant density functional theory. Contrary to non-relativistic density functional theories these fields, which are important for a proper description of nuclear systems with broken time-reversal symmetry, are uniquely defined in the CDFT framework. Hyperdeformed nuclear shapes (with semi-axis ratio 2.5:1 and larger) have been studied in the Z = 40-58 part of nuclear chart. We strongly believe that such shapes could be studied experimentally in the future with full scale GRETA detector.

  11. Effect of hot working on the damping capacity and mechanical properties of AZ31 magnesium alloy

    Science.gov (United States)

    Lee, K.; Kang, C.; Kim, K.

    2015-04-01

    Magnesium alloys have received much attention for their lightweight and other excellent properties, such as low density, high specific strength, and good castability, for use in several industrial and commercial applications. However, both magnesium and its alloys show limited room-temperature formability owing to the limited number of slip systems associated with their hexagonal close-packed crystal structure. It is well known that crystallographic texture plays an important role in both plastic deformation and macroscopic anisotropy of magnesium alloys. Many authors have concentrated on improving the room- temperature formability of Mg alloys. However, despite having a lot of excellent properties in magnesium alloy, the study for various properties of magnesium alloy have not been clarified enough yet. Mg alloys are known to have a good damping capacity compared to other known metals and their alloys. Also, the damping properties of metals are generally recognized to be dependent on microstructural factors such as grain size and texture. However, there are very few studies on the relationship between the damping capacity and texture of Magnesium alloys. Therefore, in this study, specimens of the AZ31 magnesium alloy, were processed by hot working, and their texture and damping property investigated. A 60 mm × 60 mm × 40 mm rectangular plate was cut out by machining an ingot of AZ31 magnesium alloy (Mg-3Al-1Zn in mass%), and rolling was carried out at 673 K to a rolling reduction of 30%. Then, heat treatment was carried out at temperatures in the range of 573-723 K for durations in the range of 30-180 min. The samples were immediately quenched in oil after heat treatment to prevent any change in the microstructure. Texture was evaluated on the compression planes by the Schulz reflection method using nickel-filtered Cu Kα radiation. Electron backscatter diffraction measurements were conducted to observe the spatial distribution of various orientations. Specimens

  12. Characterization of AZ31 magnesium alloy by duplex process combining laser surface melting and plasma electrolytic oxidation

    Science.gov (United States)

    Liu, Cancan; Liang, Jun; Zhou, Jiansong; Li, Qingbiao; Wang, Lingqian

    2016-09-01

    Top ceramic coatings were fabricated on the laser surface melting (LSM) modified AZ31 alloy by plasma electrolytic oxidation (PEO) in a phosphate electrolyte. The effect of LSM treatment on the microstructure and corrosion behavior of the bare and PEO treated AZ31 alloy was evaluated. Results showed that LSM treatment produced a homogeneous modified layer with redistributed intermetallic compounds, resulting in enhanced corrosion resistance of AZ31 alloy. The LSM treatment had no obvious influence on the surface and cross-sectional microstructures of the PEO coatings on AZ31 alloy. Besides, MgO was the main constituent for PEO coatings, regardless of LSM pretreatment. However, the long-term corrosion properties of the PEO coated AZ31 alloy with LSM pretreatment revealed large enhancement. Based on the analysis of microstructure and corrosion property, the corrosion mechanisms of the PEO and LSM-PEO coated AZ31 alloy were proposed.

  13. Particles and Nuclei, Letters

    International Nuclear Information System (INIS)

    The present collection of letters from JINR, Dubna, contains eight separate letters on analysis of experimental data on relativistic nuclear collisions in the Lobachevski space, relativistic contribution of the final-state interaction to deuteron photodisintegration, on the charge asymmetry of the like-sign lepton pairs induced by B - B bar - production asymmetry, limits on the νe → νe neutrino oscillation parameters from an experiment at the IHEP-JINR neutrino detector, excitation of high spin isomers in photonuclear reactions, study of product formation in proton-nuclear reactions on the 129I target induced by 660-MeV protons, application of jet pumps in the cryogenic system of the Nuclotron - superconducting accelerator of relativistic particles and study of the silicon drift detector performance with inclined tracks

  14. Nuclei as topological solitons

    International Nuclear Information System (INIS)

    The application of the Skyrme model to the construction of interaction and current operators for nuclear systems is reviewed. The long-range behaviors of these operators are found to agree with results of phenomenological meson theories based on effective chiral Lagrangians. The Skyrme model thus provides a compact method for obtaining long-range parts of such operators, consistent with the usual soft-pion theorems as well as with the requirement of current conservation. Predictions of the short-range parts of the operators remain uncertain due to difficulties in solving the equations of motion for the two-nucleon problem. The usual factorized ansatz for the soliton field of the two-nucleon system does not give sufficient accuracy at short range. The possibility of an improvement which would allow the construction of spin and isospin operators for the individual nucleons is discussed. The Skyrme model is discussed in the limit of large baryon number

  15. Synthesis of AzPhchitosan-bifenthrin-PVC to protect cables against termites.

    Science.gov (United States)

    Zhang, Lingkun; Cai, Weiwei; Chen, Wu-Ya; Zhang, Li; Hu, Kaikai; Guan, Yan-Qing

    2016-03-30

    The destruction of PVC cables by termites is a continuing and long-standing problem, which can lead to power leakage and power cut. Given the environmental demerits of insecticide overuse, alternative methods of addressing this problem are a highly desirable goal. In this study, we used photo-immobilization to develop a chitosan carrier system to help bifenthrin immobilize on the surface of the PVC substrate. The immobilization was analyzed using nuclear magnetic resonance (NMR), UV absorption, reverse-phase high-performance liquid chromatography (RP-HPLC), Raman absorption spectroscopy, and thermal gravimetric analysis (TGA). The surface structure and biological activity of the embedded and immobilized bifenthrin were examined using scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photon-electron spectroscopy (XPS). Its efficacy was assessed in pest experiments. The results indicate a successful embedding and immobilization of bifenthrin. Furthermore, the chemical bonding network between AzPhchitosan, bifenthrin, and PVC is stable, guaranteeing no environmental release of bifenthrin, and also providing more efficacious protection against termites. The evidence suggests that this photo-immobilization of bifenthrin-embedded chitosan on the surface of PVC substrates is a novel and environmentally friendly technique for termite control. This paper also reports a modification of chitosan with respect to its novel application in environmental protection. PMID:26794946

  16. Investigation on the Explosive Welding of 1100 Aluminum Alloy and AZ31 Magnesium Alloy

    Science.gov (United States)

    Chen, Pengwan; Feng, Jianrui; Zhou, Qiang; An, Erfeng; Li, Jingbo; Yuan, Yuan; Ou, Sanli

    2016-07-01

    The undesirable properties of magnesium alloys include easy embrittlement, low oxidation resistance, and difficulty in welding with other materials. Their application in industry is, therefore, restricted. In this paper, plates of 1100 aluminum alloy and AZ31 magnesium alloy were successfully welded together using the explosive welding technique. The influences of the welding parameters on the weld quality were investigated. The surface morphology and microstructure near the weld interface were examined by optical microscopy, scanning electron microscopy (equipped with energy-dispersive x-ray spectroscopy), and transmission electron microscopy. The experimental results demonstrated the typical wavy bonding interface. In addition, elemental diffusion with a thickness of approximately 3 μm occurred near the bonding interface. The two plates were joined together well at the atomic scale. Nanograins with a size of approximately 5 nm were observed in the diffusion layer. The microhardness and shear strength were measured to evaluate the mechanical properties, which confirmed that a high quality of bonding was acquired.

  17. Investigation on the Explosive Welding of 1100 Aluminum Alloy and AZ31 Magnesium Alloy

    Science.gov (United States)

    Chen, Pengwan; Feng, Jianrui; Zhou, Qiang; An, Erfeng; Li, Jingbo; Yuan, Yuan; Ou, Sanli

    2016-06-01

    The undesirable properties of magnesium alloys include easy embrittlement, low oxidation resistance, and difficulty in welding with other materials. Their application in industry is, therefore, restricted. In this paper, plates of 1100 aluminum alloy and AZ31 magnesium alloy were successfully welded together using the explosive welding technique. The influences of the welding parameters on the weld quality were investigated. The surface morphology and microstructure near the weld interface were examined by optical microscopy, scanning electron microscopy (equipped with energy-dispersive x-ray spectroscopy), and transmission electron microscopy. The experimental results demonstrated the typical wavy bonding interface. In addition, elemental diffusion with a thickness of approximately 3 μm occurred near the bonding interface. The two plates were joined together well at the atomic scale. Nanograins with a size of approximately 5 nm were observed in the diffusion layer. The microhardness and shear strength were measured to evaluate the mechanical properties, which confirmed that a high quality of bonding was acquired.

  18. Time Dependent Magnesium AZ31B Behavior: Experimental and Physically based Modeling Investigation

    Science.gov (United States)

    Rodriguez, A. K.; Ayoub, G.; Kridli, G.; Zbib, H.

    The need to produce vehicles with improved fuel efficiency and reduced emissions has led the automotive industry to consider use of "lightweighting" materials in the construction of automotive body and chassis systems. For automotive body structures and closure panel applications, mostly made of sheet, aluminum alloys are being introduced due to their lower densities and relatively high specific strengths, as well as their compatibility with the traditional manufacturing process that are used with steel. However, interest has been increasingly focusing on the use of sheet magnesium in the manufacturing of panels and structural components, since its density is about 40% lower compared to aluminum. Accordingly, the objectives of this study are to investigate the evolution of microstructure during thermo-mechanical processing of twin-roll cast AZ31B alloys sheets, and to examine the mechanical properties of the alloy under superplastic conditions. The rate dependent crystal plasticity model have been used and integrated using an explicit model was coupled with the Taylor polycrystal model in the aim to capture the overall behavior of our studied material.

  19. Novel smart stannate based coatings of self-healing functionality for AZ91D magnesium alloy

    International Nuclear Information System (INIS)

    Smart stannate based coatings were used for improving the corrosion resistance of AZ91D alloy. The proposed coatings characterize with their safety compared with the process involving toxic chromate. They are also industrially applicable and economically attractive where only two steps are needed for the coating preparation and the chemicals used are just a diluted tin-oxide solution. The electrochemical behavior and the self-healing characteristics due to stannate coatings on Mg substrate has been evaluated in 3.5% NaCl solution. Polarization measurements, electrochemical impedance spectroscopy, SEM–EDS analyses were performed to assess the performance of the coatings in NaCl and to determine the optimum conditions for self-healing ability. Results showed that stannate coatings improve the resistance to localized corrosion and micro-cracks due to formation of tin oxide-rich magnesium hydroxide layer. It was confirmed that stannate are promising coatings provide a self-healing functionality for Mg substrate that heal the pitting zones and auto-repair the micro-cracks

  20. The correlation between the impression and double shear creep of AZ31 magnesium alloy

    International Nuclear Information System (INIS)

    This study reports the application of an impression creep test to measure the creep behavior of AZ31 magnesium alloy. The correlation between the impression and double shear creep data on the same sample was determined. The creep parameters determined via impression and double shear creep assessments were found to be identical, with n = ∼3.5 and Q = ∼109.1 kJ/mol in the low-stress region, indicating that creep deformation was found to be controlled by the viscous glide of dislocations and that the viscous glide was governed by the diffusion of aluminum atoms in magnesium. The punching stress conversion factor α was determined to be 3.4 with a correlation factor β = 0.755. The Dorn constant A was determined to be 11.4 s−1. The ratio of As to Ai was 967.8, which is close to the predicted value of 928.6. This fact indicates that the impression creep relationship and double shear creep relationship can be converted into the equivalent uniaxial creep relationship.

  1. Characterisation and modelling of defect formation in direct-chill cast AZ80 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Mackie, D.; Robson, J.D.; Withers, P.J. [School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom); Turski, M. [Magnesium Elektron UK, Rake Lane, Manchester, M27 8BF (United Kingdom)

    2015-06-15

    Wrought magnesium alloys for demanding structural applications require high quality defect free cast feedstock. The aim of this study was to first identify and characterise typical defects in direct chill cast magnesium–aluminium–zinc (AZ) alloy billet and then use modelling to understand the origins of these defects so they can be prevented. Defects were first located using ultrasonic inspection and were then characterised using X-ray computed tomography (XCT) and serial sectioning, establishing the presence of oxide films and intermetallic particles Al{sub 8}Mn{sub 5} in all defects. A model was developed to predict the flow patterns and growth kinetics of the intermetallic phases during casting, which influence the formation of defects. Simulation of the growth of the intermetallic particles demonstrated that precipitation from the liquid occurs in the mould. The combination of the entrained oxide films and intermetallic particles recirculates in the liquid metal and continues to grow, until large enough to settle, which is predicted to occur at the centre of the mould where the flow is the slowest. Based on these predictions, strategies to reduce the susceptibility to defect formation are suggested. - Highlights: • Casting defects in magnesium direct chill casting have been imaged and characterised in 3-dimensions. • The occurrences of co-located clusters of particles and oxide films have been characterised and explained. • A coupled model has been developed to help interpret the observed trend for defects located towards the centre of billets.

  2. Characterisation and modelling of defect formation in direct-chill cast AZ80 alloy

    International Nuclear Information System (INIS)

    Wrought magnesium alloys for demanding structural applications require high quality defect free cast feedstock. The aim of this study was to first identify and characterise typical defects in direct chill cast magnesium–aluminium–zinc (AZ) alloy billet and then use modelling to understand the origins of these defects so they can be prevented. Defects were first located using ultrasonic inspection and were then characterised using X-ray computed tomography (XCT) and serial sectioning, establishing the presence of oxide films and intermetallic particles Al8Mn5 in all defects. A model was developed to predict the flow patterns and growth kinetics of the intermetallic phases during casting, which influence the formation of defects. Simulation of the growth of the intermetallic particles demonstrated that precipitation from the liquid occurs in the mould. The combination of the entrained oxide films and intermetallic particles recirculates in the liquid metal and continues to grow, until large enough to settle, which is predicted to occur at the centre of the mould where the flow is the slowest. Based on these predictions, strategies to reduce the susceptibility to defect formation are suggested. - Highlights: • Casting defects in magnesium direct chill casting have been imaged and characterised in 3-dimensions. • The occurrences of co-located clusters of particles and oxide films have been characterised and explained. • A coupled model has been developed to help interpret the observed trend for defects located towards the centre of billets

  3. Biodegradation behavior of micro-arc oxidized AZ31 magnesium alloys formed in two different electrolytes

    International Nuclear Information System (INIS)

    Highlights: ► Phosphate coating has lesser degradation rate than silicate coating in r-SBF solution. ► Farringtonite phase is chemically more stable than forsterite phase in SBF solution. ► Apatite forming ability of forsterite containing coating is better than farringtonite containing film. ► The hydrophilisity nature of silicate film on magnesium alloy with respect to its roughness, is greater than phosphate film. - Abstract: Degradation behavior of coated magnesium alloys is among most prominent factors for their biomedical applications. In this study, bio-corrosion behavior of micro-arc oxidized magnesium AZ31 alloys formed in silicate and phosphate baths was investigated in r-SBF medium. For this purpose polarization behavior and open circuit profile of the coated samples were achieved by electrochemical and immersion tests, respectively. Moreover, the morphology and composition of the coatings were evaluated before and after immersion test using scanning electron microscopy, X-ray diffraction and energy dispersive spectroscopy. The results showed that the phosphate film had better corrosion resistance and greater thickness than silicate film and, in turn, the lesser degradability in SBF solution, so that Ca2+ and PO43− containing compounds were more abundant on silicate film than phosphate film. Moreover phosphate film had greater surface roughness and lesser hydrophilic nature.

  4. Clustering aspects of sd shell nuclei studied by AMD

    International Nuclear Information System (INIS)

    The new clustering aspects of sd-shell nuclei found by the recent application of the antisymmetrized molecular dynamics are reported. In this paper we present two topics, 'superdeformed band of 32S and 16O + 16O clustering' and 'molecular-orbital and di-nuclei states in 22Ne'. In the first topic, it will be shown that the superdeformed band of 32S has a considerable amount of 16O + 16O cluster component, and can be regarded as to belong to a family of the 16O + 16O molecular bands. In the second topic, the presence of the molecularorbital band which has an α + 16O cluster core surrounded by two covalently neutrons is suggested together with an α + 18O di-nuclei band

  5. Isobar doorway approach to pion scattering on open shell nuclei

    International Nuclear Information System (INIS)

    Delta-hole approach developed for the pion scattering on closed shell nuclei is extended to be applied to the case of open shell nuclei. The doorway space is spanned by the states of the form vertical strokeΨ(A-1) x ψ(Δ)> which correspond to vertical strokeΔ x h> states in the usual delta-hole approach for closed shell nuclei. In this approach, the effects of the couplings between elastic and inelastic channels are incorporated in a natural way. As a first application of this approach, some numerical calculations have been done for the elastic and inelastic pion scattering on 12C and the elastic scattering on 14N and 14C. The effects of the nuclear structure and the coupling between elastic and inelastic channels are discussed. (orig.)

  6. Obesidad y azúcar: aliados o enemigos

    Directory of Open Access Journals (Sweden)

    Arturo Lisbona Catalán

    2013-07-01

    Full Text Available En las últimas tres décadas, la prevalencia de obesidad en los países desarrollados ha alcanzado dimensiones epidémicas y continua en aumento¹. Existen múltiples factores que influyen en la incidencia de obesidad, y junto con el descenso de actividad física ,el exceso de ingesta, juega un papel preponderante en la aparición de este problema de salud pública². Aunque existe una clara relación entre la ingesta de grasas y la ganancia de peso, el papel de los carbohidratos y más concretamente el de la sacarosa en el desarrollo de obesidad es más controvertido. Gran parte de esta controversia se debe a la creciente demanda de bebidas azucaradas y al posible incremento calórico en la dieta asociado a su consumo. A pesar de la publicación de múltiples estudios y comunicaciones a este respecto en los últimos años, siguen existiendo numerosas incógnitas acerca del papel que juegan las dietas ricas en azúcares en el incremento de incidencia y prevalencia de obesidad en los últimos años.

  7. Microstructural development of high temperature deformed AZ31 magnesium alloys

    International Nuclear Information System (INIS)

    Due to their significant role in automobile industries, high temperature deformation of Mg–Al–Zn alloys (AZ31) at constant stress (i.e. creep) were studied at a wide range of stresses and temperatures to characterize underlying deformation mechanism, dynamic recrystallization (DRX) and dislocation density evolution. Various microstructures (e.g. grain growth & DRX) are noted during steady-state creep mechanisms such as grain boundary sliding (GBS), dislocation glide creep (DGC) and dislocation climb creep (DCC). Although a combination of DRX and grain growth is characteristic of low stacking fault energy materials like Mg alloys at elevated temperatures, observation reveals grain growth at low strain-rates (GBS region) along with dynamic recovery (DRV) mechanism. X-Ray Diffraction (XRD) analysis revealed a decrease in dislocation density during GBS region while it increased under dislocation based creep mechanisms which could be related to the possible DRV and DRX respectively. Scanning Electron Microscopic (SEM) characterization of the fracture surface reveals more inter-granular fracture for large grains (i.e. GBS region with DRV process) and more dimple shape fracture for small grains (i.e. DGC & DCC region with DRX)

  8. Microstructural development of high temperature deformed AZ31 magnesium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Shahbeigi Roodposhti, Peiman, E-mail: pshahbe@ncsu.edu; Sarkar, Apu; Murty, Korukonda Linga

    2015-02-25

    Due to their significant role in automobile industries, high temperature deformation of Mg–Al–Zn alloys (AZ31) at constant stress (i.e. creep) were studied at a wide range of stresses and temperatures to characterize underlying deformation mechanism, dynamic recrystallization (DRX) and dislocation density evolution. Various microstructures (e.g. grain growth & DRX) are noted during steady-state creep mechanisms such as grain boundary sliding (GBS), dislocation glide creep (DGC) and dislocation climb creep (DCC). Although a combination of DRX and grain growth is characteristic of low stacking fault energy materials like Mg alloys at elevated temperatures, observation reveals grain growth at low strain-rates (GBS region) along with dynamic recovery (DRV) mechanism. X-Ray Diffraction (XRD) analysis revealed a decrease in dislocation density during GBS region while it increased under dislocation based creep mechanisms which could be related to the possible DRV and DRX respectively. Scanning Electron Microscopic (SEM) characterization of the fracture surface reveals more inter-granular fracture for large grains (i.e. GBS region with DRV process) and more dimple shape fracture for small grains (i.e. DGC & DCC region with DRX)

  9. Leading twist nuclear shadowing phenomena in hard processes with nuclei

    CERN Document Server

    Frankfurt, L; Strikman, M

    2011-01-01

    We present and discuss the theory and phenomenology of the leading twist theory of nuclear shadowing which is based on the combination of the generalization of Gribov-Glauber theory, QCD factorization theorems, and HERA QCD analysis of diffraction in lepton-proton deep inelastic scattering (DIS). We apply this technique for the analysis of a wide range of hard processes with nuclei---inclusive DIS on deuterons, medium-range and heavy nuclei, coherent and incoherent diffractive DIS with nuclei, and hard diffraction in proton-nucleus scattering---and make predictions for the effect of nuclear shadowing in the corresponding sea quark and gluon parton distributions. We also analyze the role of the leading twist nuclear shadowing in generalized parton distributions in nuclei and in certain characteristics of final states in nuclear DIS. We discuss the limits of applicability of the leading twist approximation for small x scattering off nuclei and the onset of the black disk regime and methods of detecting it. It w...

  10. Direct Electroless Nickel Plating on AZ91D Magnesium Alloy from a Sulfate Solution and its Deposition Mechanism

    Institute of Scientific and Technical Information of China (English)

    GUChang-dong; LIANJian-she; LIGuang-yu; NIULi-yuan; JIANGZhong-hao

    2004-01-01

    A bath of electroless plating Ni on the AZ91D magnesium alloy, containing sulfate nickel, was given in this paper. The nucleation mechanism of Ni-P deposits on the AZ91D magnesium alloy was studied by using XRD and SEM. The electroless Ni-P deposits were preferentially nucleated on the β(Mg17Al12) phase and extended to the primary and eutectic α phases of the AZ91D magnesium alloy.

  11. Proceedings of biological applications of relativistic nuclei

    International Nuclear Information System (INIS)

    The workshop BARN 92 on various aspects of radiation treatment of tumours and of biological radiation effects on living system hosted 38 short papers. Each is indexed and abstracted separately for the INIS database. (R.P.)

  12. Cluster Structure of Atomic Nuclei and Nucleosynthesis

    International Nuclear Information System (INIS)

    It is shown that the static and dynamic α-cluster models of nuclei, which describe an elastic electron scattering, photodisintegration reactions and pion double charge exchange reactions on α-cluster nuclei are in favor of the α-capture and α process of the formation of these nuclei

  13. Transmutations of atomic nuclei in hadron-nuclei nuclear collisions at GeV energies

    International Nuclear Information System (INIS)

    In hadron-nuclei nuclear collisions nuclei change their mass numbers A and the charge numbers Z. The mechanism of transmutation of a target nucleus was prompted experimentally and is described in this work. The information about the nuclei transmutation may be a basis for elaboration of the method of nuclei changes in beams of hadrons from accelerators

  14. A study on the relationships between corrosion properties and chemistry of thermally oxidised surface films formed on polished commercial magnesium alloys AZ31 and AZ61

    Energy Technology Data Exchange (ETDEWEB)

    Feliu, Sebastián, E-mail: sfeliu@cenim.csic.es [Centro Nacional de Investigaciones Metalúrgicas CSIC, Avda. Gregorio del Amo 8, 28040 Madrid (Spain); Samaniego, Alejandro [Centro Nacional de Investigaciones Metalúrgicas CSIC, Avda. Gregorio del Amo 8, 28040 Madrid (Spain); Barranco, Violeta [Instituto de Ciencias de Materiales de Madrid, ICMM, Consejo Superior de Investigaciones Científicas, CSIC, Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049, Madrid (Spain); El-Hadad, A.A. [Physics Department, Faculty of Science, Al-Azhar University, Nasr City 11884, Cairo (Egypt); Llorente, Irene [Centro Nacional de Investigaciones Metalúrgicas CSIC, Avda. Gregorio del Amo 8, 28040 Madrid (Spain); Serra, Carmen [Servicio de Nanotecnologia y Análisis de Superficies, CACTI, Universidade de Vigo, 36310 Vigo (Spain); Galván, J.C. [Centro Nacional de Investigaciones Metalúrgicas CSIC, Avda. Gregorio del Amo 8, 28040 Madrid (Spain)

    2014-03-01

    Highlights: • Surface chemistry of heat treated magnesium alloys. • Relation between heat treatment and aluminium subsurface enrichment. • Relation between surface composition and corrosion behaviour. - Abstract: This paper studies the changes in chemical composition of the thin oxide surface films induced by heating in air at 200 °C for time intervals from 5 min to 60 min on the freshly polished commercial AZ31 and AZ61 alloys with a view to better understanding their protective properties. This thermal treatment resulted in the formation of layers enriched in metallic aluminium at the interface between the outer MgO surface films and the bulk material. A strong link was found between the degree of metallic Al enrichment in the subsurface layer (from 10 to 15 at.%) observed by XPS (X-ray photoelectron spectroscopy) in the AZ61 treated samples and the increase in protective properties observed by EIS (electrochemical impedance spectroscopy) in the immersion test in 0.6 M NaCl. Heating for 5–60 min in air at 200 °C seems to be an effective, easy to perform and inexpensive method for increasing the corrosion resistance of the AZ61 alloy by approximately two or three times.

  15. Dynamic behavior and constitutive modeling of magnesium alloys AZ91D and AZ31B under high strain rate compressive loading

    Science.gov (United States)

    Xiao, Jing; Ahmad, Iram Raza; Shu, D. W.

    2014-03-01

    The dynamic stress-strain characteristics of magnesium alloys have not been sufficiently studied experimentally. Thus, the present work investigated compressive dynamic stress-strain characteristics of two representative magnesium alloys: AZ91D and AZ31B at high strain rates and elevated temperatures. In order to use the stress-strain characteristics in numerical simulations to predict the impact response of components, the stress-strain characteristics must be modeled. The most common approach is to use accepted constitutive laws. The results from the experimental study of the response of magnesium alloys AZ91D and AZ31B under dynamic compressive loading, at different strain rates and elevated temperatures are presented here. Johnson-Cook model was used to best fit the experimental data. The material parameters required by the model were obtained and the resultant stress-strain curves of the two alloys for each testing condition were plotted. It is found that the dynamic stress-strain relationship of both magnesium alloys are strain rate and temperature dependent and can be described reasonably well at high strain rates and room temperature by Johnson-Cook model except at very low strains. This might be due to the fact that the strain rate is not strictly constant in the early stage of deformation.

  16. Characterization of Ni–P coating on AZ91D magnesium alloy with surfactants and nano-additives

    OpenAIRE

    Mohammed Sahal

    2014-01-01

    Direct electroless Ni–P plating was done on AZ91D magnesium alloy by immersing magnesium AZ91D samples into a bath containing Nickel sulphate. The nucleation mechanism of Ni–P deposits on the AZ91D magnesium alloy in the presence of surfactants and nano-additives was studied by using SEM. The electroless Ni–P deposits were preferentially nucleated on the βMg17Al12 phase of AZ91D magnesium alloy. Ni–P coating was coated uniformly in the presence of surfactants. Effect of surfactant C-Tab with ...

  17. Neutron-rich nuclei studied with AMD

    International Nuclear Information System (INIS)

    Antisymmetrized molecular dynamics (AMD) which is a newly constructed theory of quantum-mechanical microscopic simulation of heavy ion collisions is explained to present us with a very useful theoretical approach for the study of the structure-changes which occur when we go from ordinary nuclei to exotic neutron-rich nuclei. It is because of the flexible nature of the AMD wave function which can describe the formation and dissolution of clusters both in collision problems and in structure problems. After brief explanation of successful applications of AMD to heavy ion collisions and that of the frictional cooling technique for constructing minimum-energy wave functions, the results of the AMD analyses of Li, Be, and B isotopes are discussed. Very good reproduction of magnetic moments is obtained and is explained to be related with the structure-change between cluster structure and shell-model-like structure within each isotope. The superposition of AMD determinants is shown to reproduce neutron halo structure. (orig.)

  18. Microscopy characterization of Alumina-Zirconia-Silica (AZS) refractory treated in molten vitreous environment

    International Nuclear Information System (INIS)

    Alumina-Zirconia-Silica (AZS) is being used as a glass-contact refractory in ceramic melter for vitrification of high level radioactive liquid waste (HLW). Molten vitreous mass formed during the fusion of glass forming oxides and modifiers provide hostile corrosive environment. The surface alteration of AZS refractory having intimate contact with molten vitreous mass at a temperature of 975 deg C for long duration was carried out by electron microscopy of the exposed specimen of the AZS interface. A specimen sample of AZS of proper dimension was prepared using diamond cutting machine and was suspended with a platinum wire in the pool of molten vitreous mass in such a way that the level of the molten mass covers half of the specimen height. The entire setup was then isothermally heated at 975 deg C for 800 hrs in a resistance heating furnace. At the end of the exposure period, the sample was cut to expose the cross section of the sample and was mounted and was metallographic prepared. The cross-section was characterized for image and micro chemical analysis using CAMECA SX 100 electron probe micro analyzer (EPMA). A steady beam current of 20 nA and 20 kV acceleration voltage were used for the purpose of analysis. Wavelength Dispersive Spectroscopy (WDS) was used to study the distribution of various elements in the AZS/glass sample Backscattered electron (BSE) images of the interface between AZS refractory and glass at two different locations. Both the images show that the interface between AZS and glass is diffused and continuous. No cracks, pores or discontinuity could be observed at the interface

  19. Phase coexistence in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Gulminelli, F

    2003-05-01

    In this work the general theory of first order phase transitions in finite systems is discussed, with a special emphasis to the conceptual problems linked to a thermodynamic description for small, short-lived systems de-exciting in the vacuum as nuclear samples coming from heavy ion collisions. After a short review of the general theory of phase transitions in the framework of information theory; we will present the different possible extensions to the field of finite systems. The concept of negative heat capacity, developed in the early seventies in the context of self-gravitating systems, will be reinterpreted in the general framework of convexity anomalies of thermo-statistical potentials. The connection with the distribution of the order parameter will lead us to a definition of first order phase transitions in finite systems based on topology anomalies of the event distribution in the space of observations. A careful study of the thermodynamic limit will provide a bridge with the standard theory of phase transitions and show that in a wide class of physical situations the different statistical ensembles are irreducibly inequivalent. In the second part of the paper we will apply the theoretical ideas developed in the first part to the possible observation of a liquid-to-gas-like phase transition in heavy ion collisions. The applicability of equilibrium concepts in a dynamical collisional process without boundary conditions will first be critically discussed. The observation of abnormally large partial energy fluctuations in carefully selected samples of collisions detected with the MULTICS-Miniball array will then be reported as a strong evidence of a first order phase transition with negative heat capacity in the nuclear equation of state. (author)

  20. Phase coexistence in nuclei

    International Nuclear Information System (INIS)

    In this work the general theory of first order phase transitions in finite systems is discussed, with a special emphasis to the conceptual problems linked to a thermodynamic description for small, short-lived systems de-exciting in the vacuum as nuclear samples coming from heavy ion collisions. After a short review of the general theory of phase transitions in the framework of information theory; we will present the different possible extensions to the field of finite systems. The concept of negative heat capacity, developed in the early seventies in the context of self-gravitating systems, will be reinterpreted in the general framework of convexity anomalies of thermo-statistical potentials. The connection with the distribution of the order parameter will lead us to a definition of first order phase transitions in finite systems based on topology anomalies of the event distribution in the space of observations. A careful study of the thermodynamic limit will provide a bridge with the standard theory of phase transitions and show that in a wide class of physical situations the different statistical ensembles are irreducibly inequivalent. In the second part of the paper we will apply the theoretical ideas developed in the first part to the possible observation of a liquid-to-gas-like phase transition in heavy ion collisions. The applicability of equilibrium concepts in a dynamical collisional process without boundary conditions will first be critically discussed. The observation of abnormally large partial energy fluctuations in carefully selected samples of collisions detected with the MULTICS-Miniball array will then be reported as a strong evidence of a first order phase transition with negative heat capacity in the nuclear equation of state. (author)

  1. Effect of the chemistry and structure of the native oxide surface film on the corrosion properties of commercial AZ31 and AZ61 alloys

    Energy Technology Data Exchange (ETDEWEB)

    Feliu, Sebastian, E-mail: sfeliu@cenim.csic.es [Centro Nacional de Investigaciones Metalurgicas CSIC, Avda. Gregorio del Amo 8, 28040 Madrid (Spain); Maffiotte, C. [CIEMAT-DT edificio 30, Avda. Complutense, 22, 28040 Madrid (Spain); Samaniego, A.; Galvan, Juan Carlos [Centro Nacional de Investigaciones Metalurgicas CSIC, Avda. Gregorio del Amo 8, 28040 Madrid (Spain); Barranco, Violeta [Centro Nacional de Investigaciones Metalurgicas CSIC, Avda. Gregorio del Amo 8, 28040 Madrid (Spain); Instituto de Ciencias de Materiales de Madrid, ICMM, Consejo Superior de Investigaciones Cientificas, CSIC, Sor Juana Ines de la Cruz, 3, Cantoblanco, 28049, Madrid (Spain)

    2011-08-01

    The purpose of this study has been to advance in knowledge of the chemical composition, structure and thickness of the thin native oxide film formed spontaneously in contact with the laboratory atmosphere on the surface of freshly polished commercial AZ31 and AZ61 alloys with a view to furthering the understanding of protection mechanisms. For comparative purposes, and to more fully describe the behaviour of the native oxide film, the external oxide films formed as a result of the manufacturing process (as-received condition) have been characterised. The technique applied in this research to study the thin oxide films (thickness of just a few nanometres) present on the surface of the alloys has basically been XPS (X-ray photoelectron spectroscopy) in combination with ion sputtering. Corrosion properties of the alloys were studied in 0.6 M NaCl by measuring charge transfer resistance values, which are deduced from EIS (electrochemical impedance spectroscopy) measurements after 1 h of exposure. Alloy AZ61 generally showed better corrosion resistance than AZ31, and the freshly polished alloys showed better corrosion resistance than the alloys in as-received condition. This is attributed to a combination of (1) higher thickness of the native oxide film on the AZ61 alloy and (2) greater uniformity of the oxide film in the polished condition. The formation of an additional oxide layer composed by a mixture of spinel (MgAl{sub 2}O{sub 4}) and MgO seems to diminish the protective properties of the passive layer on the surface of the alloys in as-received condition.

  2. Effects of carbon dioxide plasma immersion ion implantation on the electrochemical properties of AZ31 magnesium alloy in physiological environment

    Science.gov (United States)

    Xu, Ruizhen; Yang, Xiongbo; Zhang, Xuming; Wang, Mei; Li, Penghui; Zhao, Ying; Wu, Guosong; Chu, Paul K.

    2013-12-01

    Plasma immersion ion implantation (PIII) is conducted to improve the intrinsically poor corrosion properties of biodegradable AZ31 magnesium alloy in the physiological environment. Carbon dioxide is implanted into the samples and X-ray photoelectron spectroscopy and scanning electron microscopy are used to characterize the materials. The corrosion properties are systematically studied by potentiodynamic polarization tests in two simulated physiological environments, namely simulated body fluids and cell culture medium. The plasma-implanted materials exhibit a lower initial corrosion rate. Being a gaseous ion PIII technique, conformal ion implantation into an object with a complex shape such as an orthopedic implant can be easily accomplished and CO2 PIII is a potential method to improve the biological properties of magnesium and its alloys in clinical applications.

  3. Effects of carbon dioxide plasma immersion ion implantation on the electrochemical properties of AZ31 magnesium alloy in physiological environment

    International Nuclear Information System (INIS)

    Plasma immersion ion implantation (PIII) is conducted to improve the intrinsically poor corrosion properties of biodegradable AZ31 magnesium alloy in the physiological environment. Carbon dioxide is implanted into the samples and X-ray photoelectron spectroscopy and scanning electron microscopy are used to characterize the materials. The corrosion properties are systematically studied by potentiodynamic polarization tests in two simulated physiological environments, namely simulated body fluids and cell culture medium. The plasma-implanted materials exhibit a lower initial corrosion rate. Being a gaseous ion PIII technique, conformal ion implantation into an object with a complex shape such as an orthopedic implant can be easily accomplished and CO2 PIII is a potential method to improve the biological properties of magnesium and its alloys in clinical applications.

  4. Evolution of active galactic nuclei

    CERN Document Server

    Merloni, Andrea

    2012-01-01

    [Abriged] Supermassive black holes (SMBH) lurk in the nuclei of most massive galaxies, perhaps in all of them. The tight observed scaling relations between SMBH masses and structural properties of their host spheroids likely indicate that the processes fostering the growth of both components are physically linked, despite the many orders of magnitude difference in their physical size. This chapter discusses how we constrain the evolution of SMBH, probed by their actively growing phases, when they shine as active galactic nuclei (AGN) with luminosities often in excess of that of the entire stellar population of their host galaxies. Following loosely the chronological developments of the field, we begin by discussing early evolutionary studies, when AGN represented beacons of light probing the most distant reaches of the universe and were used as tracers of the large scale structure. This early study turned into AGN "Demography", once it was realized that the strong evolution (in luminosity, number density) of ...

  5. Multiple phonon excitation in nuclei

    International Nuclear Information System (INIS)

    The studies of multiphonon excitations in nuclei are reviewed both from the theoretical and experimental points of view. The presence of giant resonances in nuclei is described in the framework of macroscopic and microscopic models and the relative merits of different probes to excite such states are illustrated. The existence of giant resonances built on excited states is stressed. An exhaustive description of the theoretical estimates of the properties of the multiphonon states is presented. The theory predicts that such multiple collective excitations should closely follow a harmonic pattern. Recent experimental results on the double giant dipole resonance using the (π+π-) double charge exchange reaction are shown. The status of the search for isoscalar multiphonon excitations by means of the strong nuclear potential produced by heavy ions is presented. Conclusions are drawn and new prospects are discussed. (authors) 293 refs., 67 figs., 8 tabs

  6. Relativistic description of deformed nuclei

    International Nuclear Information System (INIS)

    The author has shown that relativistic Hartree calculations using parameters that have been fit to the properties of nuclear matter can provide a good description of both spherical and axially deformed nuclei. The quantitative agreement with experiment is equivalent to that which was obtained in non-relativistic calculations using Skyrme interactions. The equilibrium deformation is strongly correlated with the size of the spin-orbit splitting, and that parameter sets which give roughly the correct value for this splitting provide the best agreement with the quadrupole moments in the s-d shell. Finally, for closed shell +/- 1 nuclei, it was shown that the self-consistent calculations are able to reproduce the experimental magnetic moments. This was not possible in relativistic calculations which include only the effects of the valence orbital

  7. Moessbauer effects on oriented nuclei

    International Nuclear Information System (INIS)

    Standard nuclear orientation methods (not sensitive to the polarization) do not give information on the sign of the magnetic moment. Mossbauer effect separates right-hand and left-hand circularly polarized components, thus its detection on oriented nuclei (T approximately 10 mK) gives the sign of the magnetic moment of oriented state. In this thesis we applied this method to study the 3/2- ground states of 191Pt and 193Os, which are in the prolate-oblate transition region, where assignement of experimental levels to theoretical states is often umbiguous. We show that for those nuclei the sign of the magnetic moment is the signature of the configuration, and its determination establishes the correspondance between experimental and theoretical levels

  8. Phonon operators for deformed nuclei

    International Nuclear Information System (INIS)

    The mathematical formalism with the phonon operators independent of the signature of the angular momentum projection turns out to be inadequate for describing excited states of deformed nuclei. New phonon operators are introduced which depend on the signature of the angular momentum projection on the symmetry axis of a deformed nucleus. It is shown that the calculations with the new phonons take correctly into account the Pauli principle in two-phonon components of wave functions. The results obtained differ from those given by the phonons independent of the signature of the angular momentum projection. The new phonons must be used in deformed nuclei at taking systematically the Pauli principle into account and in calculations involving wave functions of excited states having components with more than one-phonon operator

  9. Compton Scattering on Light Nuclei

    Directory of Open Access Journals (Sweden)

    Shukla D.

    2010-04-01

    Full Text Available Compton scattering on light nuclei (A = 2, 3 has emerged as an effective avenue to search for signatures of neutron polarizabilities, both spin–independent and spin–dependent ones. In this discussion I will focus on the theoretical aspect of Compton scattering on light nuclei; giving first a brief overview and therafter concentrating on our Compton scattering calculations based on Chiral effective theory at energies of the order of pion mass. These elastic γd and γHe-3 calculations include nucleons, pions as the basic degrees of freedom. I will also discuss γd results where the ∆-isobar has been included explicitly. Our results on unpolarized and polarization observables suggest that a combination of experiments and further theoretical efforts will provide an extraction of the neutron polarizabilities.

  10. Phonon operators in deformed nuclei

    International Nuclear Information System (INIS)

    For the description of the excited states in deformed nuclei new phonon operators are introduced, which depend on the sign of the angular momentum projection onto the symmetry axis of a deformed nucleus. In the calculations with new phonons the Pauli principle is correctly taken into account in the two-phonon components of the wave functions. There is a difference in comparison with the calculation with phonons independent of the sign of the angular momentum projection. The new phonons should be used in deformed nuclei if the Pauli principle is consistently taken into account and in the calculations with the excited state wave functions having the components with more than one phonon operator

  11. Cooper pairs in atomic nuclei

    International Nuclear Information System (INIS)

    We describe recent efforts to study Cooper pairs in atomic nuclei. We consider a self-consistent Hartree Fock mean field for the even Sm isotopes and compare results based on three treatments of pairing correlations: a BCS treatment, a number-projected BCS treatment and an exact treatment using the Richardson Ansatz. Significant differences are seen in the pairing correlation energies. Furthermore, because it does not average over the properties of the fermion pairs, the Richardson solution permits a more meaningful definition of the Cooper wave function and of the fraction of pairs that are collective. Our results confirm that only a few pairs near the Fermi surface in realistic atomic nuclei are collective. (Author)

  12. Cooper pairs in atomic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Pittel, S. [Bartol Research Institute and Department of Physics and Astronomy, University of Delaware, Newark, 19716 Delaware (United States); Dussel, G. G. [Departamento de Fisica J.J. Giambiagi, Universidad de Buenos Aires, 1428 Buenos Aires (Argentina); Dukelsky, J.; Sarriguren, P. [Instituto de Estructura de la Materia, CSIC, Serrano 123, 28006 Madrid (Spain)

    2008-12-15

    We describe recent efforts to study Cooper pairs in atomic nuclei. We consider a self-consistent Hartree Fock mean field for the even Sm isotopes and compare results based on three treatments of pairing correlations: a BCS treatment, a number-projected BCS treatment and an exact treatment using the Richardson Ansatz. Significant differences are seen in the pairing correlation energies. Furthermore, because it does not average over the properties of the fermion pairs, the Richardson solution permits a more meaningful definition of the Cooper wave function and of the fraction of pairs that are collective. Our results confirm that only a few pairs near the Fermi surface in realistic atomic nuclei are collective. (Author)

  13. Direct Reactions with Exotic Nuclei

    International Nuclear Information System (INIS)

    We discuss recent work on Coulomb dissociation and an effective-range theory of low-lying electromagnetic strength of halo nuclei. We propose to study Coulomb dissociation of a halo nucleus bound by a zero-range potential as a homework problem. We study the transition from stripping to bound and unbound states and point out in this context that the Trojan-Horse method is a suitable tool to investigate subthreshold resonances

  14. Triaxial rotation in atomic nuclei

    Institute of Scientific and Technical Information of China (English)

    CHEN Yong-Shou; GAO Zao-Chun

    2009-01-01

    The Projected Shell Model has been developed to include the spontaneously broken axial symmetry so that the rapidly rotating triaxial nuclei can be described microscopically. The theory provides an useful tool to gain an insight into how a triaxial nucleus rotates, a fundamental question in nuclear structure. We shall address some current interests that are strongly associated with the triaxial rotation. A feasible method to explore the problem has been suggested.

  15. Neurotransmitters of the suprachiasmatic nuclei

    OpenAIRE

    Reghunandanan, Vallath; Reghunandanan, Rajalaxmy

    2006-01-01

    There has been extensive research in the recent past looking into the molecular basis and mechanisms of the biological clock, situated in the suprachiasmatic nuclei (SCN) of the anterior hypothalamus. Neurotransmitters are a very important component of SCN function. Thorough knowledge of neurotransmitters is not only essential for the understanding of the clock but also for the successful manipulation of the clock with experimental chemicals and therapeutical drugs. This article reviews the c...

  16. Weak pion production from nuclei

    Indian Academy of Sciences (India)

    S K Singh; M Sajjad Athar; Shakeb Ahmad

    2006-04-01

    The charged current pion production induced by neutrinos in 12C, 16O and 56Fe nuclei has been studied. The calculations have been done for the coherent as well as the incoherent processes assuming dominance and takes into account the effect of Pauli blocking, Fermi motion and the renormalization of in the nuclear medium. The pion absorption effects have also been taken into account.

  17. Direct Reactions with Exotic Nuclei

    CERN Document Server

    Baur, G

    2005-01-01

    We discuss recent work on Coulomb dissociation and an effective-range theory of low-lying electromagnetic strength of halo nuclei. We propose to study Coulomb dissociation of a halo nucleus bound by a zero-range potential as a homework problem. We study the transition from stripping to bound and unbound states and point out in this context that the Trojan-Horse method is a suitable tool to investigate subthreshold resonances.

  18. An introduction to mesic nuclei

    CERN Document Server

    Wilkin, Colin

    2016-01-01

    There is much speculation and a modest amount of evidence that certain mesons might form quasi-bound states with nuclei to produce really exotic states of matter. For this to be a practical possibility, the interaction between the meson and nucleons at low energies must be strong and attractive and the production rates "healthy". The conditions for this are surveyed for the light mesons. How this might lead to quasi-bound states is then discussed in a few typical cases.

  19. Weak pion production from nuclei

    International Nuclear Information System (INIS)

    The charged current pion production induced by neutrinos in 12C, 16O and 56Fe nuclei has been studied. The calculations have been done for the coherent as well as the incoherent processes assuming Δ dominance and takes into account the effect of Pauli blocking, Fermi motion and the renormalization of Δ in the nuclear medium. The pion absorption effects have also been taken into account. (author)

  20. Geometric symmetries in light nuclei

    CERN Document Server

    Bijker, Roelof

    2016-01-01

    The algebraic cluster model is is applied to study cluster states in the nuclei 12C and 16O. The observed level sequences can be understood in terms of the underlying discrete symmetry that characterizes the geometrical configuration of the alpha-particles, i.e. an equilateral triangle for 12C, and a regular tetrahedron for 16O. The structure of rotational bands provides a fingerprint of the underlying geometrical configuration of alpha-particles.

  1. Proton scattering from unstable nuclei

    Indian Academy of Sciences (India)

    Y Blumenfeld; E Khan; F Maréchal; T Suomijärvi

    2001-08-01

    Recent improvements in the intensities and optical qualities of radioactive beams have made possible the study of elastic and inelastic proton scattering on unstable nuclei. The design and performances of an innovative silicon strip detector array devoted to such experiments are described. The quality of the data obtained are illustrated with recent results obtained at the GANIL facility for unstable oxygen, sulfur and argon isotopes. Methods to analyse the data using phenomenological and microscopic optical model potentials are discussed.

  2. PREFACE: Correlation Dynamics in Nuclei

    Science.gov (United States)

    Suzuki, Toshio; Otsuka, Takaharu; Ichimura, Munetake

    2005-01-01

    The International Symposium on `Correlation Dynamics in Nuclei' was held at the Sanjo Kaikan, the University of Tokyo, from the 31 January to 4 February 2005. This symposium was organized on the occasion of the 50th anniversary of the Configuration Mixing theory of Arima and Horie. The symposium was hosted by the University of Tokyo, and supported by the Inoue Foundation for Science, the Japan Atomic Energy Research Institute and the Ministry of Education, Culture, Sports, Science and Technology. The purpose of the symposium was to discuss theoretical and experimental developments and future prospects in physics of correlation dynamics in nuclei, including topics such as effective interactions, shell model studies of configuration mixing and spin-isospin modes in nuclei. It was shown in many ways and angles that the Arima-Horie theory has been a starting point of a variety of developments of the studies in these fields over many decades. The developments have been enhanced by the expansion of computational capabilities and the progress in accelerators, detectors and radioactive beam facilities. We enjoyed 28 excellent and lively invited talks and 30 oral presentations in the symposium with about 90 participants. A special session was dedicated to celebrate the 80th birthday of Professor Igal Talmi, who made invaluable and pioneering works in the shell model theory. Finally, we would like to thank all the speakers and the participants as well as the other organizers for their contributions which made the symposium very successful.

  3. EFFECTS OF Ce ON CORROSION RESISTANCE OF AZ91D MAGNESIUM ALLOY

    Institute of Scientific and Technical Information of China (English)

    Z.H. Huang; X.F. Guo; Z.M. Zhang; C.J. Xu

    2005-01-01

    As-cast and corrosive microstructures of AZ91D alloy containing various Ce contents were observed by optical microscope (OM). The phase compositions of the alloys before and after the corrosion were analyzed by X-ray diffraction (XRD). Meanwhile, the corrosion resistance of the alloys was tested by weight loss and potentiodynamic polarization curve methods respectively.The results show that rod-like Al4Ce phase is formed in AZ91D alloy containing certain Ce content and as-cast microstructures are refined. AZ91D-0. 7%Ce alloy has good grain refinementeffect. The addition of Ce can reduce the corrosion rate and corrosion current density of AZ91Dalloy and those of AZ91D-0. 1%Ce alloy reach the minimum, which are 0.35mg/(cm2·d) and2.761μA/cm2 with 75% and 86% reduction, respectively. The increasing volume fraction and reticular degree of β phase can improve the corrosion resistance of the alloys.

  4. Caña de azúcar en Colombia

    Directory of Open Access Journals (Sweden)

    Ramos Gómez, Oscar Gerardo

    2005-04-01

    Full Text Available This article studies the sugar industry in Colombia, mainly in the Cauca Valley. The analysis is focused on the technical evolution undergone since its inception and the way in which a «sugar culture» evolved. This work also studies the participation of «hacendados» and croppers during the Independence period and the formation of republican oligarchies, their adaptation to the economy modernization processes in the 20th Century, as well as the State intervention and the associative mechanisms the sector used to confront the 1930 crisis. These mechanisms helped to expand the sector. Finally the recent performance of the sugar industry is analyzed, mainly its growth in the seventies and the present efforts at competitiveness, environmental impact and situation in the world trade.

    Este artículo analiza la industria azucarera en Colombia, sobre todo en el Valle del Cauca, su evolución técnica desde sus orígenes y el modo en que se fue configurando una cultura de la caña de azúcar. Además, estudia la participación de los hacendados y cultivadores en la independencia y la formación de las oligarquías republicanas, su adaptación a la modernización de la economía nacional en el siglo XX y la intervención el Estado y los mecanismos asociativos con que hizo frente el sector a la crisis de 1930 y que dieron lugar a una notable expansión del mismo. La parte final del texto explora el desempeño reciente de dicha actividad, su fuerte crecimiento en el decenio de 1970 y sus actuales esfuerzos por mejorar su competitividad, impacto medioambiental y posición en el comercio mundial.

  5. Compressed Baryonic Matter: from Nuclei to Pulsars

    CERN Document Server

    Xu, Renxin

    2013-01-01

    Our world is wonderful because of the negligible baryonic part although unknown dark matter and dark energy dominate the Universe. Those nuclei in the daily life are forbidden to fuse by compression due to the Coulomb repulse, nevertheless, it is usually unexpected in extraterrestrial extreme-environments: the gravity in a core of massive evolved star is so strong that all the other forces (including the Coulomb one) could be neglected. Compressed baryonic matter is then produced after supernova, manifesting itself as pulsar-like stars observed. The study of this compressed baryonic matter can not only be meaningful in fundamental physics (e.g., the elementary color interaction at low-energy scale, testing gravity theories, detecting nano-Hertz background gravitational waves), but has also profound implications in engineering applications (including time standard and navigation), and additionally, is focused by Chinese advanced telescopes, either terrestrial or in space. Historically, in 1930s, L. Landau spec...

  6. Clusters in neutron-rich light nuclei

    Directory of Open Access Journals (Sweden)

    Jelavić Malenica D.

    2016-01-01

    Full Text Available Due to their high selectivity, transfer and sequential decay reactions are powerful tools for studies of both single particle (nucleon and cluster states in light nuclei. Their use is particularly simple for investigations of α-particle clustering (because α-particle has Jπ=0+, which simplifies spin and parity assignments to observed cluster states, but they are also easily applicable to other types of clustering. Recent results on clustering in neutron-rich isotopes of beryllium, boron and carbon obtained measuring the 10B+10B reactions (at 50 and 72 MeV are presented. The highly efficient and segmented detector systems used, built from 4 Double Sided Silicon Strip Detectors (DSSSD allowed detection of double and multiple coincidences and, in that way, studies of states populated in transfer reactions, as well as their sequential decay.

  7. Corrosion behaviour and in vitro/in vivo biocompatibility of surface-modified AZ31 alloy; Comportamiento frente a la corrosion y biocompatibilidad in vitrolin vivo de la aleacion AZ31 modificada superficialmente

    Energy Technology Data Exchange (ETDEWEB)

    Carboneras, M.; Iglesias, C.; Perez-Maceda, B. T.; Valle, J. A. de; Garcia-Alonso, M. C.; Alobera, M. A.; Clemente, C.; Rubio, J. C.; Escudero, M. I.; Lozano, R. M.

    2011-07-01

    The present work evaluates the corrosion behaviour and the in vitro/in vivo biocompatibility of the AZ31 magnesium alloy, which fulfills the mechanical requirements of bone. The corrosion kinetic of as-received AZ31 alloy was not compatible with the cell growth. To improve its performance, the AZ31 alloy was surface modified by a chemical conversion treatment in hydrofluoric acid. The magnesium fluoride layer generated by the surface treatment of AZ31 alloy enhances its corrosion behaviour, allowing the in vitro growth of osteoblastic cells over the surface and the in vivo formation of a highly compact layer of new bone tissue. These results lead to consider the magnesium fluoride coating as necessary for potential use of the AZ31 alloy as biodegradable and absorbable implant for bone repair. (Author) 18 refs.

  8. Improvement on the Corrosion Resistance of AZ91D Magnesium Alloy by Aluminum Diffusion Coating

    Institute of Scientific and Technical Information of China (English)

    Hongwei HUO; Ying LI; Fuhui WANG

    2007-01-01

    By combination of magnetron sputtering deposition and vacuum annealing, an aluminum diffusion coating was prepared on the substrate of AZ91D alloy to improve its corrosion resistance. The microstructure and composition of the diffusion coating was investigated by scanning electron microscopy and X-ray diffraction. The diffusion coating was mainly comprised of β phase-Al12Mg17. The continuous immersion test in 3.5 wt pct neutral NaCl solution indicated that the specimen with diffusion coating had better corrosion resistance compared with the bare AZ91D alloy specimen. The potentiodynamic polarization measurement indicated that the diffusion coating could function as an effectively protective layer to reduce the corrosion rate of AZ91D alloy when exposed to 3.5 wt pct NaCl solution.

  9. Microstructure and corrosion property of AZ61 magnesium alloy by electromagnetic stirring

    Institute of Scientific and Technical Information of China (English)

    FANG Can-feng; ZHANG Xing-guo; JI Shou-hua; JIN Jun-ze; CHANG Yu-bao

    2005-01-01

    The influence of permanent-magnet-driven stirring during solidification on the microstructure and corrosion property of AZ61 magnesium alloy was investigated. The corrosion behaviour of AZ61 was studied in 3.5mol/L NaCl by measuring electrochemical polarization. The results show that the permanent-magnet stirring refines the microstructure of AZ61 magnesium alloy, which improves the precipitation amount and distribution uniformity of β phase and decreases the content of hydrogen, but it has less influence on the distribution uniformity of Zn. The change of precipitation amount of β phase influences the corrosive nature of the matrix, and it has no direct proportion with the corrosion resistance of the matrix.

  10. Hot rolling characteristics of spray-formed AZ91 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-feng; ZHAO Jiu-zhou; HE Jie; HU Zhuang-qi

    2007-01-01

    AZ91 magnesium alloy was prepared by spray forming. The spray-deposited alloy was subsequently hot-rolled with a 80% reduction at 350 ℃. The microstructural features of the as-spray-deposited and hot-rolled alloy were examined by optical microscopy, scanning electron microscopy and X-ray diffractometry. The results show that the spray-formed AZ91 magnesium alloy has, compared with the as-cast ingot, a finer microstructure with less intermetallic phase Mg17Al12 dispersed in the matrix due to fast cooling and solidification rates of spray forming process, and, therefore showing excellent workability. It can be hot-rolled with nearly 20% reduction for one pass at lower temperatures (330-360℃), and the total reduction can reach 50% prior to annealing. After proper thermo-mechanical treatment, the spray-formed AZ91 magnesium alloy exhibits outstanding mechanical properties.

  11. Research on the inhibition mechanism of tetraphenylporphyrin on AZ91D magnesium alloy

    International Nuclear Information System (INIS)

    Highlights: ► Environment-friendly tetraphenylporphyrin is synthesized in the lab. ► The tetraphenylporphyrin can efficiently inhibit AZ91D corrosion. ► The inhibitor chelates with Mg ions to form a film retarding Mg dissolution. - Abstract: 5,10,15,20-Tetraphenylporphyrin (TPP) is synthesized and its inhibition effect on AZ91D magnesium alloy in 0.05 wt.% NaCl solution is studied. Electrochemical measurement and immersion corrosion test results indicate that the inhibition efficiency of TPP reaches 90%. SEM, FT-IR, ultraviolet–visible absorption spectrum (UV), fluorescent spectrometry and XPS analyses suggest that TPP molecules can chelate with Mg via their N atoms to form a TPP–Mg complex, which can precipitate as a film on AZ91D alloy. The precipitated TPP–Mg reduces the porosity of the original Mg(OH)2 surface film and retards the dissolution of the Mg alloy.

  12. Effects of Ce on damping capacity of AZ91D magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    黄正华; 郭学锋; 张忠明

    2004-01-01

    The microstructures and damping capacity of AZ91D cast alloys containing various Ce contents were investigated. Damping capacity (Q-1) of the alloys was measured by cantilever beam technique, and the relationship between damping capacity and strain amplitude was investigated. The results show that Al4 Ce phase is formed in AZ91D alloy after adding a certain quantity of Ce contents, then as-cast microstructures of the alloys are refined.Meanwhile the damping capacity of the alloys is also improved. When the mass fraction of Ce is 0.7 %, the most obvious refinement effect and the maximum damping capacity can be obtained. When the damping capacity (Q-1) is 2. 728 × 10-3 , 61% increment can be obtained compared with unmodified AZ91D alloy. The damping capacity of the alloys is relative to strain amplitude, and the damping behavior can be explained by the theory of Granato and Lucke.

  13. Microstructure and mechanical properties of AZ31 Mg alloy processed by high ratio extrusion

    Institute of Scientific and Technical Information of China (English)

    CHEN Yong-jun; WANG Qu-dong; LIN Jin-bao; ZHANG Lu-jun; ZHAI Chun-quan

    2006-01-01

    The microstructure and mechanical properties of AZ31 Mg alloy processed by high ratio extrusion (HRE) were investigated. General extrusion with extrusion ratio of 7 and high ratio extrusion with extrusion ratio 100 were contrastively conducted at 250, 300 and 350 ℃. The results show that HRE process may be applied successfully to AZ31 Mg alloy at temperatures of 250, 300 and 350 ℃ and this leads to obvious grain refinement during HRE process. The strength of HRE process is improved obviously compared with that of general extrusion. The grain refining mechanism of HRE process was also discussed. The current results imply that the simple high ratio extrusion method might be a feasible and effective processing means for refining the microstructure and improving the mechanical properties of AZ31 Mg alloy.

  14. Influence of Procedure Parameters on Rheological Property of Semi-Solid AZ91D Magnesium Alloy

    Institute of Scientific and Technical Information of China (English)

    Jiang Yunxi; Xie Shuisheng; Li Xinggang; Li Lei

    2004-01-01

    Semi-solid AZ91D magnesium alloy was investigated in isothermal steady-state condition. The influence of stirring technological parameters such as stirring temperature and shear rate to apparent viscosity of semi-solid alloy slurry was discussed. Apparent viscosity increases with stirring temperature decreases at the same shear rate. At the same stirring temperature, apparent viscosity decreases rapidly at first with shear rate increases, and then apparent viscosity decreases slowly with shear rate increases, when shear rate reaches a certain value, apparent viscosity appears tiny increase. According to the experimental data, the relation between solid volume fraction and apparent viscosity of semi-solid AZ9l D alloy at shear rate 238 s- 1 is fitted by regression method, it supplies useful data to the numerical simulation of semi-solid AZ91D alloy die casting process.

  15. Influence of inorganic acid pickling on the corrosion resistance of magnesium alloy AZ31 sheet

    DEFF Research Database (Denmark)

    Nwaogu, Ugochukwu Chibuzoh; Blawert, C.; Scharnagl, N.;

    2009-01-01

    Surface contaminants as a result of thermo-mechanical processing of magnesium alloys, e.g. sheet rolling, can have a negative effect on the corrosion resistance of magnesium alloys. Especially contaminants such as Fe, Ni and Cu, left on the surface of magnesium alloys result in the formation...... of micro-galvanic couples and can therefore increase corrosion attack on these alloys. Due to this influence they should be removed to obtain good corrosion resistance. In this study, the effect of inorganic acid pickling on the corrosion behaviour of a commercial AZ31 magnesium alloy sheet...... cleaning the AZ31 sheet. However, to obtain reasonable corrosion resistance at least 5 mu m of the surface of AZ31 magnesium alloy sheet have to be removed....

  16. Review on theoretical researches of superheavy nuclei

    International Nuclear Information System (INIS)

    We review the recent progress of theoretical researches on heavy nuclei and superheavy nuclei. At first we analyze the experimental data of long lifetime heavy nuclei and discuss their stability. Then the calculated binding energies and alpha-decay energies of heavy and superheavy nuclei from different models are compared and discussed. This includes the results from the local binding energy formula of heavy nuclei with Z ≥ 90 and N ≥ 130, those from the relativistic mean-field model, and from other models. For the local binding energy formula, it can reproduce experimental binding energies of known heavy and superheavy nuclei well. The relativistic mean-field model and non-relativistic mean-field model show that there is shape coexistence in superheavy nuclei. For some superheavy nuclei, superdeformed prolate shape can be their ground states and there are isomers in lowly excited states due to shape coexistence. The properties of some unknown superheavy nuclei are predicted. Some new views on the stability and on half-lives of heavy and superheavy nuclei are presented. Possible new phenomenon in superheavy region is analyzed and discussed. (author)

  17. Effect of filler wire on the joint properties of AZ31 magnesium alloys using CO2 laser welding

    Institute of Scientific and Technical Information of China (English)

    Wang Hongying; Li Zhijun

    2007-01-01

    Laser welding with filler wire of AZ31 magnesium alloys is investigated using a CO2 laser experimental system. The effect of three different filler wires on the joint properties is researched. The results show that the weld appearance can be effectively improved when using laser welding with filler wire. The microhardness and tensile strength of joints are almost the same as those of the base metal when ER AZ31 or ER AZ61 wire is adopted. However, when the filler wire of ER 5356 aluminum alloy is used, the mechanical properties of joints become worse. For ER AZ31 and ER AZ61 filler wires, the microstructure of weld zone shows small dendrite grains. In comparison, for ER 5356 filler wire, the weld shows a structure of snowy dendrites and many intermetallic compounds and eutectic phases distribute in the dendrites. These intermetallic constituents with low melting point increase the tendency of hot crack and result in fragile joint properties. Therefore, ER AZ31 and ER AZ61 wire are more suitable filler material than ER 5356 for CO2 laser welding of AZ31 magnesium alloys.

  18. 14 CFR Appendix to Subpart U of... - Special Flight Rules in the Vicinity of the Grand Canyon National Park, AZ

    Science.gov (United States)

    2010-01-01

    ... Grand Canyon National Park, AZ Appendix to Subpart U of Part 93 Aeronautics and Space FEDERAL AVIATION... TRAFFIC RULES Special Flight Rules in the Vicinity of Grand Canyon National Park, AZ Pt. 93, Subpt. U, App. Appendix to Subpart U of Part 93—Special Flight Rules in the Vicinity of the Grand Canyon National Park,...

  19. 14 CFR Special Federal Aviation... - 2-Special Flight Rules in the Vicinity of the Grand Canyon National Park, AZ

    Science.gov (United States)

    2010-01-01

    ... the Grand Canyon National Park, AZ Federal Special Federal Aviation Regulation No. 50 Aeronautics and... No. 50-2—Special Flight Rules in the Vicinity of the Grand Canyon National Park, AZ Section 1... airspace, designated as the Grand Canyon National Park Special Flight Rules Area: That airspace...

  20. Patrón de consumo e ingestas recomendadas de azúcar

    Directory of Open Access Journals (Sweden)

    Joan Quiles i Izquierdo

    2013-07-01

    Full Text Available Los azúcares son hidratos de carbono con sabor dulce que proveen energía al organismo. El cerebro adulto utiliza aproximadamente 140 g de glucosa al día, cantidad que puede representar hasta el 50% del total de hidratos de carbono que se consumen. En nuestro país el patrón de consumo de azúcar en alimentos permanece constante, mientras que el consumo de bebidas refrescantes presenta un aumento en los últimos cuatro años. La Encuesta Nacional de Ingesta Dietética de España (ENIDE, 2010-11 estimó que un 20% de la ingesta calórica de los españoles procede de los hidratos de carbono denominados azúcares. Se ha asociado el consumo de azúcar con diversas patologías (diabetes, obesidad, caries, cardiovasculares si bien estas relaciones no presentan consistencia en las evidencias encontradas. La información alimentaria a través del etiquetado nutricional, incluida la relativa a los azúcares presentes en los alimentos, facilitada al consumidor persigue proteger la salud de los mismos y garantizar su derecho a la información para que puedan tomar decisiones con criterio. A la vista de las distintas valoraciones y estudios existentes y sobre todo, en ausencia de una evidencia científica sólida que arroje datos concretos sobre los que realizar recomendaciones, el mejor consejo nutricional para la población general podría ser llevar una dieta variada y equilibrada con alimentos y nutrientes procedentes de diversas fuentes, combinando dicha dieta con el ejercicio y la actividad física. De manera más concreta, un consumo moderado de azúcar (< 10% de la energía total en el anterior contexto de dieta variada y equilibrada, es compatible.

  1. Microstructure and corrosion behavior of electrodeposited nano-crystalline nickel coating on AZ91 Mg alloy

    Energy Technology Data Exchange (ETDEWEB)

    Zarebidaki, Arman, E-mail: arman.zare@iauyazd.ac.ir; Mahmoudikohani, Hassan, E-mail: hassanmahmoudi.k@gmail.com; Aboutalebi, Mohammad-Reza

    2014-12-05

    Highlights: • Activation, zincating, and Cu electrodeposition were used as pretreatment processes for electrodeposition of nickel coatings. • Nano-crystalline nickel coatings were successfully electrodeposited onto the AZ91 Mg alloys. • Effect of nickel electrodeposited coating on the corrosion resistance of AZ91 Mg alloy has been studied. - Abstract: In order to enhance the corrosion resistance, nickel coating was electrodeposited onto AZ91 Mg alloy. Activation, zincating, and Cu electrodeposition used as pretreatment processes for better adhesion and corrosion performance of the nickel over layer. The corrosion properties of the AZ91 Mg alloy, nickel electroplated AZ91 Mg alloy, and pure nickel was assessed via polarization and electrochemical impedance spectroscopy (EIS) methods in 3.5 wt% NaCl solution. Moreover, the structure of the coating was investigated by means of X-ray diffraction, whereas specimen’s morphology and elemental composition were analyzed using scanning electron microscope (SEM) equipped with energy dispersive spectrometer (EDS). Measurements revealed that the coating has a nano-crystalline structure with the grain size of 95 nm. Corrosion results showed superior corrosion resistance for the coated AZ91 Mg alloy as the corrosion current density decreased from 2.5 × 10{sup −4} A cm{sup −2}, for the uncoated sample, to 1.5 × 10{sup −5} A cm{sup −2}, for coated specimen and the corrosion potential increased from −1.55 V to −0.98 V (vs. Ag/AgCl) at the same condition.

  2. Nanomechanical analysis of AZ31 magnesium alloy and pure magnesium correlated with crystallographic orientation

    International Nuclear Information System (INIS)

    The anisotropic nanomechanical properties of AZ31 magnesium alloy and pure Mg were measured in situ via nanoindentation of individual grains with simultaneous observations using a scanning electron microscope. Values of the nanohardness, indentation size effect, elastic modulus, and yield strength were correlated with the crystallographic orientation provided by electron backscattering diffraction and were further used to investigate the relationships between the nanomechanical properties of the materials and the work of nanoindentation. The nanohardness of AZ31 was found to be generally above that of pure Mg due to solid solution strengthening. The nanohardness of AZ31 first considerably decreased and then marginally increased, whereas the nanohardness of pure Mg steadily decreased as the angle between the hexagonal lattice c-axis of both materials and the indentation direction increased. The indentation size effect was stronger for AZ31 than for pure Mg, and its magnitude decreased as the angle between the lattice c-axis and the indentation direction increased. The AZ31 modulus remained nearly constant throughout the range of investigated orientations; the modulus of pure Mg followed a theoretical angular dependence but was generally lower than expected. The yield strength behaved in a similar manner to the nanohardness in both materials. Plots of the ratio of the nanohardness to the yield strength revealed that both materials underwent significant work hardening shortly after nanoindentation began. It was also shown that the amount of plastic deformation increased for Mg and increased or remained nearly constant for AZ31 as the angle increased. The observed orientation dependencies were interpreted as a consequence of the anisotropic activities of the dominant slip systems and extension twinning

  3. Patrón de consumo e ingestas recomendadas de azúcar

    OpenAIRE

    Joan Quiles i Izquierdo

    2013-01-01

    Los azúcares son hidratos de carbono con sabor dulce que proveen energía al organismo. El cerebro adulto utiliza aproximadamente 140 g de glucosa al día, cantidad que puede representar hasta el 50% del total de hidratos de carbono que se consumen. En nuestro país el patrón de consumo de azúcar en alimentos permanece constante, mientras que el consumo de bebidas refrescantes presenta un aumento en los últimos cuatro años. La Encuesta Nacional de Ingesta Dietética de España (ENIDE, 2010-11) est...

  4. The microstructure and impression creep behavior of cast AZ80 magnesium alloy with yttrium additions

    International Nuclear Information System (INIS)

    Highlights: ► Addition of 0.5–2%Y to the AZ80 alloy improved creep resistance. ► AZ80 + 0.5Y and AZ80 + 1Y showed the highest creep resistances at low and high temperatures, respectively. ► Higher creep resistance was due to the solid solution hardening of Al and formation of the stable Al2Y compound. ► The low stress creep mechanism was climb of dislocations. ► The high stress creep mechanism was dislocation climb with additional particle strengthening. -- Abstract: The effects of 0.5, 1.0 and 2.0 wt.% Y additions on the microstructure and creep behavior of the as-cast AZ80 alloy were investigated by impression tests. The tests were performed at temperatures in the range 423–523 K, under punching stress in the range 150–650 MPa. At low temperatures up to 473 K, the AZ80 + 0.5Y alloy had the highest creep resistance among all materials tested, whereas with increasing temperature from 473 K to 523 K, the AZ80 + 1.0Y alloy had a better performance. This can be attributed to the fact that at low temperatures the presences of β-Mg17Al12 and Al2Y phases together with solid solution hardening effects of Al in the Mg matrix strengthen the AZ80 + 0.5Y alloy. At higher temperatures, AZ80 + 1.0Y with a higher volume fraction of the more thermally stable Al2Y and lower amounts of the less stable β-Mg17Al12 exhibits better creep behavior. The stress exponents and activation energies were almost the same for all alloy systems studied, 6.0–8.8 and 90–119 kJ/mol, respectively. The observed decreasing trend of creep-activation energy with stress suggests that two parallel mechanisms of lattice and pipe-diffusion-controlled dislocation climb are competing. Climb of dislocations with an additional particle strengthening effect controlled by dislocation pipe diffusion is dominant at high stresses, whereas climb of dislocations is the controlling mechanism at low stresses.

  5. Grain refinement of AZ31 magnesium alloy by electromagnetic stirring under effect of grain-refiner

    Indian Academy of Sciences (India)

    S Y Gao; Q C Le; Z Q Zhang; J Z Cui

    2012-08-01

    The effects of electromagnetic stirring and Al4C3 grain refiner on the grain refinement of semicontinuously cast AZ31 magnesium alloy were discussed in this investigation. The results indicate that electromagnetic stirring has an effective refining effect on the grain size of AZ31 magnesium alloy under the effect of Al4C3 grain refiner. Electromagnetic stirring can `activate’ the Al4C3 particles, resulting in more heterogeneous nucleation sites for the primary -Mg grains. But, longer holding time can `deactivate’ the Al4C3 particles and poison the grain refining effect.

  6. Effects of organic acid pickling on the corrosion resistance of magnesium alloy AZ31 sheet

    DEFF Research Database (Denmark)

    Nwaogu, Ugochukwu Chibuzoh; Blawert, C.; Scharnagl, N.; Dietzel, W.; Kainer, K. U.

    2010-01-01

    mu m of the contaminated surface was required to reach corrosion rates less than 1 mm/year in salt spray condition. Among the three organic acids examined, acetic acid is the best choice. Oxalic acid can be an alternative while citric acid is not suitable for cleaning AZ31 sheet, because of......Organic acids were used to clean AZ31 magnesium alloy sheet and the effect of the cleaning processes on the surface condition and corrosion performance of the alloy was investigated. Organic acid cleanings reduced the surface impurities and enhanced the corrosion resistance. Removal of at least 4...

  7. Selectividad de caña de azúcar en bovinos

    OpenAIRE

    E. M. Aranda; G.D. Mendoza; Ramos, J.A.; S. Salgado; A. C. Vitti

    2009-01-01

    Se condujo este trabajo con el objetivo de conocer la aceptación del forraje de caña de azúcar integral en la dieta con base de pasto para bovinos adultos fistulados en rumen y duodeno estabulados; para ello, se ofreció pasto estrella africana (Cynodon plectostachyus) y caña de azúcar (Saccharum officinarum) mezclada con 1% de urea a voluntad, por separado. Se midió la composición de los alimentos, consumo de materia seca, pH ruminal y duodenal. Se utilizaron técnicas de la estadística descri...

  8. Exotic light nuclei and nuclei in the lead region

    International Nuclear Information System (INIS)

    Three methods are discussed for modifying, or renormalizing, a truncated nuclear hamiltonian such that the wave functions obtained by diagonalizing this modified or effective hamiltoniandescribe the nucleus as well as possible: deriving the hamiltonian directly from a realistic nucleon-nucleon interaction between free nucleons; parametrizing the hamiltonian in terms of a number of parameters and determining these parameters from a least-squares fit of calculated properties to experimental data; approximating the nucleon-nucleon (NN) interaction between two nucleons in a nucleus by a simple analytic expression. An effective hamiltonian derived following the second method is applied in a theoretical study of exotic nuclei in the region of Z=2-9 and A=4-30 and the problem of the neutron halo in 11Li is discussed. Results of shell-model calculations of 20iPb and nuclei in its neighbourhood are presented in which an effective hamiltonian was employed derived with the last method. The quenching of M1 strength in 208Pb, and the spectroscopic factors measured in proton knock-out reactions could be described quite satisfactory. Finally, a method is presented for deriving the effective hamiltonian directly from the realistic NN interaction with algebraic techniques. (H.W.). 114 refs.; 34 figs.; 12 tabs.; schemes

  9. Effects of the types of overlap on the mechanical properties of FSSW welded AZ series magnesium alloy joints

    Science.gov (United States)

    Wang, Dan; Shen, Jun; Wang, Lin-Zhi

    2012-03-01

    The effects of the types of overlap on the mechanical properties of the friction stir spot welding (FSSW) welded AZ series magnesium alloy joints were investigated by microstructural observations, microhardness tests, and tensile tests. The results show that the microstructure of the stir zone adjacent to the periphery of the rotating pin is mainly composed of the upper sheet. The average distance D between the longitudinal segment of the curved interface and the keyhole periphery, the tensile shear force, and the microhardness of the stir zone of the FSSW welded AZ61 alloy joint are the highest in all samples. During FSSW of AZ31 and AZ61 dissimilar magnesium alloys, the irregular deformation of the longitudinal segment of the curved interface appears, while the microhardness of the stir zone is higher when AZ61 alloy is the upper sheet. Moreover, the microhardness of the stir zone increases initially and then decreases sharply in the longitudinal test position.

  10. Assessing the ecosystem service potential of Tucson AZ's urban forest

    Science.gov (United States)

    Pavao-Zuckerman, M.

    2011-12-01

    Urbanization is arguably one of the most dramatic forms of landscape change, and an important anthropogenic influence on the structure and function of ecosystems. Cities have obvious impacts on local ecologies and environments, such as shifts in species diversity and alteration of local microclimates. While scientists are now familiar with many of these localized impacts of urbanization, cities and suburban areas contribute to 10-15 % of surface land cover in the conterminous U.S., pointing to the potential, yet poorly understood, contribution of cities to regional, national, and global carbon (C) and energy budgets. As cities continue to expand urban ecologists place more emphasis on understanding the functions of urban ecosystems and the ecosystem services (e.g. habitat, air, and water quality) that cities provide. While studies demonstrate that the urban environment alters the structure and function of remnant patches of native ecosystems relative to their non-urban counterparts, the ability of restoration, planning, and design to improve the provision of ecosystem services is a new approach within ecology. One strategy involves green urban design, or using ecological principles for planning or reinvigorating certain ecological processes, in cities. Increasing the amount of vegetative cover can reduce this effect by reinforcing ecosystem services in cities, including shading of surfaces, promotion of cooling through evapotranspiration, and the sequestration of atmospheric CO2 in plant tissues and soils. However, the on-the-ground reality of such strategies is relatively unknown. A pilot study is being conducted in Tucson, AZ to investigate the impact of increasing the cover of trees in the urban landscape on local microclimates and the urban heat island. Trees (Velvet Mesquite, Chilean Mesquite, and Desert Willow) were planted in two neighborhoods in Tucson in 1990. We are collecting data during the summer 2011 monsoon (DBH, crown volume, and hemispherical

  11. Nucleon transfer between heavy nuclei

    International Nuclear Information System (INIS)

    Nucleon transfer reactions between heavy nuclei are characterized by the classical behaviour of the scattering orbits. Thus semiclassical concepts are well suited for the description of these reactions. In the present contribution the characteristics of single and multinucleon transfer reactions at energies below and above the Coulomb barrier are shown for systems like Sn+Sn, Xe+U and Ni+Pb. The role of the pairing interaction in the transfer of nucleon pairs is illustrated. For strong transitions the coupling of channels and the absorption into more complicated channels is taken into account in a coupled channels calculation

  12. Superdeformation in the bismuth nuclei

    International Nuclear Information System (INIS)

    High angular-momentum states in 196,197Bi were populated in the reaction 183W (19F,xn) at a beam energy of 108 MeV, and γ rays were detected with the Gammasphere array. Two weakly populated rotational bands, with energy spacings characteristic of superdeformation have been found. Both cascades can be assigned unambiguously to the Bi nuclei; however, their isotopic assignment to 197Bi is tentative. The properties of the bands and their possible structures are discussed. Our results represent the first identification of superdeformed bands in a nucleus of the A∼190 mass region with Z>82

  13. New Magicity of Light Nuclei

    OpenAIRE

    Samanta, C.; Adhikari, S

    2001-01-01

    A new mass formula capable of explaining the binding energies of almost all the known isotopes from Li to Bi is prescribed. In addition to identifying the new magic number at neutron number N=16 (Z=7-9), pseudo-magic numbers at N=14 (Z=7-10), Z=14 (N=13-19), and at N=6 (Z=3-8), the formula accounts for the loss of magicity for nuclei with N=8 (Z=4) and N=20 (Z=12-17). The redefinition of the neutron drip line resulting from this formula further allows us to predict the existence of 26O,31F, 3...

  14. Exotic nuclei and Yukawa's forces

    OpenAIRE

    Otsuka, Taka; Suzuki, Toshio; Utsuno, Yutaka

    2008-01-01

    In this plenary talk, we will overview the evolution of the shell structure in stable and exotic nuclei as a new paradigm of nuclear structure physics. This shell evolution is primarily due to the tensor force. The robust mechanism and some examples will be presented. Such examples include the disappearance of existing magic numbers and the appearance of new ones. The nuclear magic numbers have been believed, since Mayer and Jensen, to be constants as 2, 8, 20, 28, 50, …This turned out to be ...

  15. Collective bands in superdeformed nuclei

    International Nuclear Information System (INIS)

    The collective properties of excited superdeformed bands have been investigated in the framework of self-consistent cranked Nilsson plus quasiparticle random-phase approximation. The expected octupole nature of some bands observed recently in some nuclei has been confirmed by a comparative analysis of their E1 decays to the yrast band and of the anomalous behavior of their dynamical moment of inertia. It is also shown that the onset of supederformation affects considerably the structure of the giant resonances and greatly enhances the collectivity of the low-lying scissors mode. (author)

  16. Single Pion production from Nuclei

    International Nuclear Information System (INIS)

    We have studied charged current one pion production induced by νμ(ν-barμ) from some nuclei. The calculations have been done for the incoherent pion production processes from these nuclear targets in the Δ dominance model and take into account the effect of Pauli blocking, Fermi motion and renormalization of Δ properties in the nuclear medium. The effect of final state interactions of pions has also been taken into account. The numerical results have been compared with the recent results from the MiniBooNE experiment for the charged current 1π production, and also with some of the older experiments in Freon and Freon-Propane from CERN

  17. Microscopic properties of superdeformed nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, Lennart B

    1999-04-01

    Many high spin rotational bands in superdeformed nuclei have been found in the A 140 - 150 region, but so far no linking transitions to known normal-deformed states have been found in these nuclei. Therefore, configuration and spin assignments have to be based on indirect spectroscopic information. Identical bands were first discovered in this region of superdeformed states. At present, some identical bands have also been found at normal deformation, but such bands are more common at superdeformation. Recently lifetime measurements have given relative quadrupole moments with high accuracy. Spectroscopic quantities are calculated using the configuration constrained cranked Nilsson-Strutinsky model with the modified oscillator potential. In a statistical study the occurrence of identical bands is tested. Comparing superdeformed and normal deformed nuclei, the higher possibility for identical bands at superdeformation is understood from calculated reduced widths of the E{sub {gamma}} and J{sup (2)} distributions. The importance of high-N orbitals for identical bands is also discussed. Additivity of electric quadrupole moment contributions in the superdeformed A - 150 region is discussed with the nucleus {sup 152}Dy as a `core`. In analytic harmonic oscillator calculations, the effective electric quadrupole moment q{sub eff}, i.e. the change in the total quadrupole moment caused by the added particle, is expressed as a simple function of the single-particle mass, quadrupole moment q{sub {nu}}. Also in realistic calculations, simple relations between q{sub eff} and q{sub {nu}} can be used to estimate the total electric quadrupole moment, e.g. for the nucleus {sup 142}Sm, by adding the effect of 10 holes, to the total electric quadrupole moment of {sup 152}Dy. Furthermore, tools are given for estimating the quadrupole moment for possible configurations in the superdeformed A - 150 region. For the superdeformed region around {sup 143}Eu, configuration and spin assignments

  18. Exotic nuclei: another aspect of nuclear structure

    International Nuclear Information System (INIS)

    This document gathers the lectures made at the Joliot Curie international summer school in 2002 whose theme that year was exotic nuclei. There were 11 contributions whose titles are: 1) interactions, symmetry breaking and effective fields from quarks to nuclei; 2) status and perspectives for the study of exotic nuclei: experimental aspects; 3) the pairing interaction and the N = Z nuclei; 4) borders of stability region and exotic decays; 5) shell structure of nuclei: from stability to decay; 6) variational approach of system with a few nucleons; 7) from heavy to super-heavy nuclei; 8) halos, molecules and multi-neutrons; 9) macroscopic approaches for fusion reactions; 10) beta decay: a tool for spectroscopy; 11) the gas phase chemistry of super-heavy elements

  19. Comportamiento mecánico de la aleación AZ31 reforzada con nanofibras de carbono

    Directory of Open Access Journals (Sweden)

    Adeva, P.

    2010-12-01

    Full Text Available The aim of this study is to investigate the effect of reinforcing AZ31 with carbon nanofibres. The materials AZ31, AZ31-1 % C y AZ31-2 % C were produced by a conventional powder metallurgy route consisting of mechanical mixing of nanofibres and powders of AZ31, cool compactation and extrusion at 350 °C. After extrusion the three materials exhibited a recrystallized microstructure of similar grain size, fine and rather inhomogeneous. Furthermore, they presented a weak fibre texture with basal plane parallel to the extrusion direction. The tensile properties were affected by the nanofibres presence only at 100 °C. At this temperature, yield strength and tensile strength were 30% higher than in the unreinforced alloy.

    En este trabajo se ha estudiado el efecto de la adición de nanofibras de carbono en las propiedades mecánicas de la aleación AZ31 procesada por una ruta pulvimetalúrgica convencional. Se prepararon tres materiales, AZ31, AZ31- 1 % C y AZ31-2 % C. Tras una mezcla mecánica de las nanofibras con los polvos de AZ31, se precompactaron en frío y se extruyeron a 350 °C. Los tres presentan una microestructura recristalizada con un tamaño de grano similar, fino aunque algo heterogéneo. Los tres materiales presentan una débil textura de fibra con el plano basal paralelo a la dirección de extrusión. Las propiedades mecánicas a tracción únicamente se ven afectadas por la presencia de nanofibras a 100 °C superando los materiales reforzados en un 30 % a los valores de límite elástico y resistencia de la aleación sin reforzar.

  20. Nuclei at the limits of particle stability

    International Nuclear Information System (INIS)

    The properties and synthesis of nuclei at the limits of particle stability are reviewed. Nuclear reactions were induced and studied by means of the 'exotic' nuclear beams, i.e. beams of radioactive drip-line nuclei. The beams are mostly generated in heavy-ion projectile fragmentation. The cases of both neutron-rich and proton-rich nuclei are discussed. (K.A.) 270 refs.; 13 figs.; 1 tab

  1. The Origin of Fracture in the I-ECAP of AZ31B Magnesium Alloy

    Science.gov (United States)

    Gzyl, Michal; Rosochowski, Andrzej; Boczkal, Sonia; Qarni, Muhammad Jawad

    2015-11-01

    Magnesium alloys are very promising materials for weight-saving structural applications due to their low density, comparing to other metals and alloys currently used. However, they usually suffer from a limited formability at room temperature and low strength. In order to overcome those issues, processes of severe plastic deformation (SPD) can be utilized to improve mechanical properties, but processing parameters need to be selected with care to avoid fracture, very often observed for those alloys during forming. In the current work, the AZ31B magnesium alloy was subjected to SPD by incremental equal-channel angular pressing (I-ECAP) at temperatures varying from 398 K to 525 K (125 °C to 250 °C) to determine the window of allowable processing parameters. The effects of initial grain size and billet rotation scheme on the occurrence of fracture during I-ECAP were investigated. The initial grain size ranged from 1.5 to 40 µm and the I-ECAP routes tested were A, BC, and C. Microstructures of the processed billets were characterized before and after I-ECAP. It was found that a fine-grained and homogenous microstructure was required to avoid fracture at low temperatures. Strain localization arising from a stress relaxation within recrystallized regions, namely twins and fine-grained zones, was shown to be responsible for the generation of microcracks. Based on the I-ECAP experiments and available literature data for ECAP, a power law between the initial grain size and processing conditions, described by a Zener-Hollomon parameter, has been proposed. Finally, processing by various routes at 473 K (200 °C) revealed that route A was less prone to fracture than routes BC and C.

  2. The waste management program at VUB-AZ: An integrated solution for nuclear biomedical waste management

    International Nuclear Information System (INIS)

    In 1996 the University of Brussels and its Academic hospital (VUB-AZ) started a waste program for the nuclear biomedical waste management. This program, based on selective collection, measurement before decay, storage for decay of short-lived radionuclides, measurement after decay and eventual clearance as non-nuclear waste, has proved its effectiveness over the past 5 years. Effective characterisation for on-site storage for decay of short-lived radionuclides makes selective collection of waste streams mandatory and requires motivated and trained laboratory staff. Dynamic optimisation of this selective collection increases the efficiency of the storage for decay program. The accurate qualitative and quantitative measurement of nuclear biomedical waste before decay has several advantages such as verification of correct selective collection, optimisation of the decay period and possibility of clearance below the minimal detectable activity. Sealed waste packages are assessed for specific activity by an HPGe-detector or by a liquid scintillation counter. The WasteMan software allows a full trace-ability of all waste packages from production to either clearance or disposal. This waste storage program, including the complete measurement set-up and the necessary management software, is already installed in a second university, proving the general applicability of the whole concept for biomedical nuclear waste. Many hospitals and other biomedical centres however produce small quantities of nuclear waste for which investments in measurement equipment and decay rooms are not cost-effective. The installation of a regional centre for nuclear biomedical waste will be presented here as an alternative solution to this problem. (author)

  3. Az elváltak gazdasági körülményei az Egyesült Államokban

    OpenAIRE

    Hernádi, Miklós

    2001-01-01

    Az angolszász országokban, részben azért is, mert a családjogi bírósági tárgyalásokat in camera, vagyis nem nyilvános formában tartják, nem publikálják a meghozott határozatok összesített adatait. (Az Egyesült Államokban a családjogi ügyeket mindjárt állami szinten, vagyis a superior courtokban, nem pedig a magistrate courtokban tárgyalják.) Így nem hozzáférhetők adatok arra vonatkozóan, hogy egy-egy évben hány ügy került, és hány nem került a bíróság elé (mert peren kívül rendeződött); hány ...

  4. AZ31镁合金搅拌摩擦点焊%Friction stir spot welding of AZ31 Mg-alloy

    Institute of Scientific and Technical Information of China (English)

    尹玉环; 胡绳荪; North T.H.; 张晓博; 孙娜

    2011-01-01

    研究了搅拌头旋转频率以及停留时间对AZ31镁合金搅拌摩擦点焊接头力学性能的影响.随着旋转频率的增大,不同搅拌针条件下,AZ31搅拌摩擦点焊接头的力学性能均呈现先增大后减小的趋势.随着停留时间的延长,AZ31搅拌摩擦点焊接头的力学性能先增大随后在一定范围内波动.结果表明,结合宽度是影响搅拌摩擦点焊接头力学性能的重要因素,结合宽度越大,点焊接头的力学性能越好;此外,上下板之间界面特征对搅拌摩擦点焊接头的力学性能也具有重要的影响.

  5. Deep inelastic collisions between very heavy nuclei

    International Nuclear Information System (INIS)

    A systematic survey of deep inelastic reactions was performed for colliding nuclei of masses between 80 and 240 amu. The application of large surface detectors and, particularly, of a position sensitive ionization chamber, has proved to be very effective and appropriate for this type of investigation. The Wilczynski diagrams describing the relative motion between the colliding objects shows a gradual trend as a function of growing masses of target and projectile where the trajectories lead the particles not toward negative scattering angles but increasingly into the direction around and above the grazing angle. This behavior is attributed to a delicate balance between Coulomb and nuclear forces. The energy dumping as a function of the mass transfer strength matches a general law between total kinetic energy loss and the variance of the proton number distribution. For the partly damped component this relation seems to hold independently from the choice of ingoing channel and bombarding energy. The dissipation of the kinetic energy does not depend only on the relative velocity of the impinging nuclei, and the simple friction model is not appropriate to describe these processes. The γ-multiplicity measurement displays a rapid increase as a function of scattering angle and total kinetic energy loss, which give new insights to the process and indicate the necessity of microscopic quantum mechanical calculations of the interaction. In the U-U collision large mass transfers are present which possibly populate with relatively large cross sections the transuranic elements. In the Pb-Pb reaction the mass transfer is more restricted. The decay probability by fission of the primary masses increases strongly for growing masses and excitation energies

  6. Mass-23 nuclei in astrophysics

    Science.gov (United States)

    Fraser, P. R.; Amos, K.; Canton, L.; Karataglidis, S.; Svenne, J. P.; van der Kniff, D.

    2015-09-01

    The formation of mass-23 nuclei by radiative capture is of great interest in astrophysics. A topical problem associated with these isobars is the so-called 22Na puzzle of ONe white dwarf novae, where the abundance of 22Na observed is not as is predicted by current stellar models, indicating there is more to learn about how the distribution of elements in the universe occurred. Another concerns unexplained variations in elements abundance on the surface of aging red giant stars. One method for theoretically studying nuclear scattering is the Multi-Channel Algebraic Scattering (MCAS) formalism. Studies to date have used a simple collective-rotor prescription to model the target states which couple to projectile nucleons. While, in general, the target states considered all belong to the ground state rotor band, for some systems it is necessary to include coupling to states outside of this band. Herein we discuss an extension of MCAS to allow coupling of different strengths between such states and the ground state band. This consideration is essential when studying the scattering of neutrons from 22Ne, a necessary step in studying the mass-23 nuclei mentioned above.

  7. Selfconsistent calculations for hyperdeformed nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Molique, H.; Dobaczewski, J.; Dudek, J.; Luo, W.D. [Universite Louis Pasteur, Strasbourg (France)

    1996-12-31

    Properties of the hyperdeformed nuclei in the A {approximately} 170 mass range are re-examined using the self-consistent Hartree-Fock method with the SOP parametrization. A comparison with the previous predictions that were based on a non-selfconsistent approach is made. The existence of the {open_quotes}hyper-deformed shell closures{close_quotes} at the proton and neutron numbers Z=70 and N=100 and their very weak dependence on the rotational frequency is suggested; the corresponding single-particle energy gaps are predicted to play a role similar to that of the Z=66 and N=86 gaps in the super-deformed nuclei of the A {approximately} 150 mass range. Selfconsistent calculations suggest also that the A {approximately} 170 hyperdeformed structures have neglegible mass asymmetry in their shapes. Very importantly for the experimental studies, both the fission barriers and the {open_quotes}inner{close_quotes} barriers (that separate the hyperdeformed structures from those with smaller deformations) are predicted to be relatively high, up to the factor of {approximately}2 higher than the corresponding ones in the {sup 152}Dy superdeformed nucleus used as a reference.

  8. Interacting boson model for exotic nuclei at low isospin

    International Nuclear Information System (INIS)

    With Wigner's SU(4) supermultiplet symmetry [and its generalization to pseudo-SU(4)] as a starting point, a boson-model space is constructed that includes T = 0 as well as T = 1 bosons (IBM-4). The boson Hamiltonian is derived microscopically from a realistic shell-model interaction through a mapping that relies on the existence of approximate shell-model symmetries. Applications are presented for odd-odd N = Z nuclei from 2958Cu29 to 3570Br35. (authors)

  9. Rotating nuclei at extreme conditions: Cranked relativistic mean field description

    CERN Document Server

    Afanasjev, A V

    1999-01-01

    The cranked relativistic mean field (CRMF) theory is applied for the description of superdeformed (SD) rotational bands observed in sup 1 sup 5 sup 3 Ho. The question of the structure of the so-called SD band in sup 1 sup 5 sup 4 Er is also addressed and a brief overview of applications of CRMF theory to the description of rotating nuclei at extreme conditions is presented.

  10. Representation of the neutron cross sections of several fertile and fissile nuclei in the resonance regions

    International Nuclear Information System (INIS)

    Some problems associated with the measurement and representation of the neutron cross sections of the fertile and fissile nuclei in the resolved and unresolved resonance regions are briefly discussed. Attention is restricted to the heavy nuclei most important for nuclear reactor applications: the resonance structure of the light- and medium-weight nuclei (moderators and structural materials) has different characteristics and requires a different approach. Some of the experimental problems in neutron cross-section measurements and some of the ambiguities in the resonance analysis resulting from the use of different resonance formalisms and different treatments of the effect of far-away levels are discussed

  11. Recent shell-model results for exotic nuclei

    Directory of Open Access Journals (Sweden)

    Utsuno Yusuke

    2014-03-01

    Full Text Available We report on our recent advancement in the shell model and its applications to exotic nuclei, focusing on the shell evolution and large-scale calculations with the Monte Carlo shell model (MCSM. First, we test the validity of the monopole-based universal interaction (VMU as a shell-model interaction by performing large-scale shell-model calculations in two different mass regions using effective interactions which partly comprise VMU. Those calculations are successful and provide a deeper insight into the shell evolution beyond the single-particle model, in particular showing that the evolution of the spin-orbit splitting due to the tensor force plays a decisive role in the structure of the neutron-rich N ∼ 28 region and antimony isotopes. Next, we give a brief overview of recent developments in MCSM, and show that it is applicable to exotic nuclei that involve many valence orbits. As an example of its applications to exotic nuclei, shape coexistence in 32Mg is examined.

  12. The asymptotic hadron spectrum, anti-nuclei, hyper-nuclei and quark phase

    International Nuclear Information System (INIS)

    The only hope of determining the hadronic spectrum in the high mass region is through a study of matter produced in very high energy nuclear collisions. Along the way, exotic nuclei, i.e., anti-nuclei and hyper-nuclei may be produced in appreciable numbers, and the detection of a quark phase may be possible. (orig.)

  13. Cesium Removal From Tanks 241-AN-103 and 241-SX-105 and 241-AZ-101 and 241-AZ-102 Composite For Testing In Bench Scale Steam Reformer

    International Nuclear Information System (INIS)

    This report documents the preparation of three actual Hanford tank waste samples for shipment to the Savannah River National Laboratory (SRNL). Two of the samples were dissolved saltcakes from tank 241-AN-103 (hereafter AN-103) and tank 241-SX-105 (hereafter SX-105); one sample was a supernate composite from tanks 241-AZ-101 and 241-AZ-102 (hereafter AZ-101/102). The preparation of the samples was executed following the test plans LAB-PLAN-10-00006, Test Plan for the Preparation of Samples from Hanford Tanks 241-SX-105, 241-AN-103, 241-AN-107, and LAB-PLN-l0-00014, Test Plan for the Preparation of a Composite Sample from Hanford Tanks 241-AZ-101 and 241-AZ-102 for Steam Reformer Testing at the Savannah River National Laboratory. All procedural steps were recorded in laboratory notebook HNF-N-274 3. Sample breakdown diagrams for AN-103 and SX-105 are presented in Appendix A. The tank samples were prepared in support of a series of treatability studies of the Fluidized Bed Steam Reforming (FBSR) process using a Bench-Scale Reformer (BSR) at SRNL. Tests with simulants have shown that the FBSR mineralized waste form is comparable to low-activity waste glass with respect to environmental durability (WSRC-STI-2008-00268, Mineralization of Radioactive Wastes by Fluidized Bed Steam Reforming (FBSR): Comparisons to Vitreous Waste Forms and Pertinent Durability Testing). However, a rigorous assessment requires long-term performance data from FBSR product formed from actual Hanford tank waste. Washington River Protection Solutions, LLC (WRPS) has initiated a Waste Form Qualification Program (WP-5.2.1-2010-001, Fluidized Bed Steam Reformer Low-level Waste Form Qualification) to gather the data required to demonstrate that an adequate FBSR mineralized waste form can be produced. The documentation of the selection process of the three tank samples has been separately reported in RPP-48824, Sample Selection Process for Bench-Scale Steam Reforming Treatability Studies Using

  14. CESIUM REMOVAL FROM TANKS 241-AN-103 & 241-SX-105 & 241-AZ-101 & 241AZ-102 COMPOSITE FOR TESTING IN BENCH SCALE STEAM REFORMER

    Energy Technology Data Exchange (ETDEWEB)

    DUNCAN JB; HUBER HJ

    2011-04-21

    This report documents the preparation of three actual Hanford tank waste samples for shipment to the Savannah River National Laboratory (SRNL). Two of the samples were dissolved saltcakes from tank 241-AN-103 (hereafter AN-103) and tank 241-SX-105 (hereafter SX-105); one sample was a supernate composite from tanks 241-AZ-101 and 241-AZ-102 (hereafter AZ-101/102). The preparation of the samples was executed following the test plans LAB-PLAN-10-00006, Test Plan for the Preparation of Samples from Hanford Tanks 241-SX-105, 241-AN-103, 241-AN-107, and LAB-PLN-l0-00014, Test Plan for the Preparation of a Composite Sample from Hanford Tanks 241-AZ-101 and 241-AZ-102 for Steam Reformer Testing at the Savannah River National Laboratory. All procedural steps were recorded in laboratory notebook HNF-N-274 3. Sample breakdown diagrams for AN-103 and SX-105 are presented in Appendix A. The tank samples were prepared in support of a series of treatability studies of the Fluidized Bed Steam Reforming (FBSR) process using a Bench-Scale Reformer (BSR) at SRNL. Tests with simulants have shown that the FBSR mineralized waste form is comparable to low-activity waste glass with respect to environmental durability (WSRC-STI-2008-00268, Mineralization of Radioactive Wastes by Fluidized Bed Steam Reforming (FBSR): Comparisons to Vitreous Waste Forms and Pertinent Durability Testing). However, a rigorous assessment requires long-term performance data from FBSR product formed from actual Hanford tank waste. Washington River Protection Solutions, LLC (WRPS) has initiated a Waste Form Qualification Program (WP-5.2.1-2010-001, Fluidized Bed Steam Reformer Low-level Waste Form Qualification) to gather the data required to demonstrate that an adequate FBSR mineralized waste form can be produced. The documentation of the selection process of the three tank samples has been separately reported in RPP-48824, Sample Selection Process for Bench-Scale Steam Reforming Treatability Studies Using

  15. 75 FR 20920 - Safety Zone; Lake Havasu Grand Prix, Lake Havasu, AZ

    Science.gov (United States)

    2010-04-22

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Lake Havasu Grand Prix, Lake Havasu, AZ... temporary safety zone upon the navigable waters of Lake Havasu on the Colorado River in Lake Havasu City, Arizona for the Lake Havasu Grand Prix. This temporary safety zone is necessary to provide for the...

  16. Validation of Airborne Visible-Infrared Imaging Spectrometer Data at Ray Mine, AZ

    Science.gov (United States)

    Lang, H.; Baloga, S.

    1999-01-01

    We validate 1997 Airborne Visible-Infrared Imaging Spectrometer (AVIRIS) reflectance spectra covering 0.4 meu - 2.4 meu from a stable, flat mineralogically characterized man-made target at Ray Mine, AZ, the site for an EPA/NASA assessment of the utility of remote sensing for monitoring acid drainage from an active open pit mine.

  17. Compression Deformation Behavior of AZ81 Magnesium Alloy at Elevated Temperatures

    Directory of Open Access Journals (Sweden)

    Xiaoping Luo

    2014-01-01

    Full Text Available The hot deformation behavior of an AZ81 magnesium alloy was investigated by hot compressive testing on a Gleeble-1500 thermal mechanical simulator in the temperature range from 200 to 400°C and in the strain rate range of 0.001–5 s−1. The relationships among flow stress, strain rate, and deformation temperature were analyzed, and the deformation activation energy and stress exponent were calculated. The microstructure evolution of the AZ81 magnesium alloy under high deformation was examined. The results indicated that the maximum value of the flow stress increased with the decrease of deformation temperature and the increase of strain rate. When the deformation temperature is constant, the flow stress of the AZ81 magnesium alloy increases with the increase of strain rate, which can be demonstrated by a Zener-Hollomon parameter in a hyperbolic-sine-type equation with a hot compression deformation activation energy of 176.01 KJ/mol and basic hot deformation material factors A, n, and a in the analytical expression of the AZ81 magnesium alloy flow stress of 3.21227×1014 s−1, 7.85, and 0.00866 MPa, respectively.

  18. Thermal stability of magnesium alloy AZ91 prepared by severe plastic deformation

    OpenAIRE

    Roman Štěpánek; Libor Pantělejev; Ondřej Man

    2013-01-01

    This paper deals with the thermal stability of ultrafine-grained alloy AZ91 prepared by means of ECAP (Equal Channel Angular Pressing) method. Annealing experiments were conducted isochronally for 30 minutes in the temperature range of 220 to 400 °C in argon atmosphere. EBSD (Electron Backscatter Diffraction) method was used to image the changes in microstructure due to increased temperature.

  19. Effect of La and Nd on microstructures and mechanical properties of AZ61 wrought magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    周海涛; 曾小勤; 丁文江; 马春江; 朱燕萍

    2004-01-01

    Effects of La and Nd addition on the microstructure and mechanical properties of the AZ61 alloy have been investigated. The results show that when La and Nd are added into the AZ61 alloy respectively, the β(Mg17Al12 ) phase is refined and granulated, and new phases are formed in the form of small rod-like shape, which are verified as La3 Al11 and Nd3 Al11 phase by X-ray diffraction and TEM observation. Microstructure observations show that the effective efficiency of La addition is higher than that of Nd addition, thus the sizes ofβ(Mg17 Al12 ) and La3 Al11 phase are relatively smaller than those ofβ(Mg17 Al12 ) and Nd3 Al11 phases in both AZ61 alloy and Nd-containing alloy. The increase of the tensile strength and elongation of AZ61 alloy refers to the existence of small rod-like La3Al11 and Nd3 Al11 phases, and fine granulatedβ(Mg17 Al12) phase.

  20. Tank 241-AZ-101 steam bumping and settling Process Test report

    International Nuclear Information System (INIS)

    This report summarizes the process test in which the airlift circulators in Tank 241-AZ-101 were shutdown. The test was successful, in that no extreme temperature excursions occurred. Only general data was obtianed through the use of a gamma energy probe

  1. AZ ÖNTÖZÉS SZEREPE, JELENTÅ SÉGE

    OpenAIRE

    Lajos HELYES

    2005-01-01

    Az öntözés egyik alapvető célja, hogy javítsa az egyre növekvő népesség élel-miszerrel való ellátását. A világon jelenleg a szántóterület 17%-át öntözik, vi-szont ez a felület adja az évenként betakarítható össztermés valamivel több mint 40%-át. Hazánkban a vízjogi engedéllyel rendelkező öntözésre berendezett terü-letünk 210 ezer hektár, ami a szántóterület közel 5%-a, de a ténylegesen öntözött terület évjárattól függően ennek kb. a fele. Az Európai Unióban átlagosan a szántóterület 13,5%-a t...

  2. Mechanisms of 5-azacytidine (5AzC)-induced toxicity in the rat foetal brain

    Science.gov (United States)

    Ueno, Masaki; Katayama, Kei-Ichi; Nakayama, Hiroyuki; Doi, Kunio

    2002-01-01

    Mechanisms of 5-azacytidine (5AzC)-induced toxicity in the rat foetal brain were investigated. 5AzC (10 mg/kg) was injected into pregnant rats on day 13 of gestation and the protein and mRNA expressions of p53 and its transcriptional target genes, p21, bax, cyclin G1, fas, and gadd45, were examined in the foetal brain. The number of p53-positive cells peaked at 9 h after treatment (HAT) and those of apoptotic cells and p21-positive cells peaked at 12 HAT. The expressions of p21, bax, cyclin G1, and fas mRNAs were significantly elevated from 9 to 12 HAT. From the experiments using 5-bromo-2′-deoxyuridine (BrdU), as compared with controls, the migration of neuroepithelial cells significantly delayed and BrdU-positive signals were observed in many apoptotic cells from 9 to 24 HAT in the 5AzC-group. In addition, the number of S phase cells significantly decreased at 12 HAT. The present results indicate that 5AzC induced apoptosis and cell cycle arrest probably at G1 phase in the rat foetal brain and they might be mediated by p53 in response to DNA damage. PMID:12383193

  3. THE APPARENT VISCOSITY OF SEMI-SOLID AZ91D ALLOY AT STEADY STATE

    Institute of Scientific and Technical Information of China (English)

    Z.S. Zhen; W.M. Mao; S.J. Yan; A.M. Zhao; C.L. CuI; X.Y. Zhong

    2002-01-01

    The Rheological behavior of semi-solid AZ91D at steady state is studied using a Couettetype viscometer in the present paper. The results show that the apparent viscosity ofsemi-solid AZ91D at the steady state increases with the solid fraction increasing, andgoes up sharply when the solid fraction reaches a certain value, which is called criticalfraction. In addition, the apparent viscosity of semi-solid AZ91D at the steady statetakes on a distinct downtrend with the shearing rate increasing, which indicates astrong shear thinning property. In addition, the critical solid fraction becomes higherunder larger shearing rate, owing to the more globular shape of the solid particles.Based on the present experiment results, an empirical equation is built as that, relatingthe steady state apparent viscosity of semi-solid AZ91D with the solid fraction fs andshearing rate γ at the same time: ηapp=10. 74exp(6.95fs)γ-0.86.

  4. INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.

  5. Fatigue properties of magnesium alloy AZ91 processed by severe plastic deformation

    Czech Academy of Sciences Publication Activity Database

    Fintová, Stanislava; Kunz, Ludvík

    2015-01-01

    Roč. 42, FEB (2015), s. 219-228. ISSN 1751-6161 R&D Projects: GA ČR GAP108/10/2001 Institutional support: RVO:68081723 Keywords : AZ91 magnesium alloy * ECAP * Fatigue * Crack initiation Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 3.417, year: 2014 http://www.sciencedirect.com/science/article/pii/S1751616114003713

  6. Corrosion resistance of WE43 and AZ91D magnesium alloys with phosphate PEO coatings

    International Nuclear Information System (INIS)

    The corrosion performance of WE43-T6 and AZ91D magnesium alloys with and without treatment by plasma electrolytic oxidation (PEO) was investigated by electrochemical measurements in 3.5 wt.% NaCl solution. For untreated WE43-T6 alloy, formation of a uniform corrosion layer (Mg(OH)2) was accompanied by initial pits around magnesium-rare earth intermetallic compounds. The AZ91D alloy disclosed increased corrosion susceptibility, with localized corrosion around the β-phase, though the β-phase network phase acted as a barrier for corrosion progression. PEO treatment in alkaline phosphate electrolyte improved the corrosion resistance of WE43-T6 alloy only at the initial stages of immersion in the test solution. However, PEO-treated AZ91D alloy revealed a relatively high corrosion resistance for much increased immersion times, contrary to the relative corrosion resistances of the untreated alloys. The improved performance of the PEO-treated AZ91D alloy appears to be related to the formation of a more compact coating

  7. Effect of cooling rate on microstructure and compressive performance of AZ91 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    YANG Lin; FENG Hui; QIU Ke-qiang; CHEN Li-jia; LIU Zheng

    2006-01-01

    Effect of cooling rate on both microstructure and room temperature compressive performance of the AZ91 magnesium alloy was investigated. The experimental results show that with increasing cooling rate, the quantity of the solid solution phase increases and the fraction of secondary phase Mg17Al12 decreases. The almost single solid solution phase can be obtained with using liquid nitrogen as a coolant. The compressive strengths of the rapid solidified AZ91 magnesium alloys are higher than those of normal cast alloy, and decrease with increasing cooling rate. After artificial aging treatment for 14 h at 168 ℃, the compressive strength of the rapidly solidified AZ91 magnesium alloy cooled in liquid nitrogen increases from 253.5 to 335.3 MPa, while the compressive yield strength increases from 138.1 to 225.91 MPa. The improvement in the compressive strength of the rapidly solidified AZ91magnesium alloys can be attributed to the hardening effect from fine secondary phase.

  8. Microstructure refinement of AZ91D alloy solidified with pulsed magnetic field

    Institute of Scientific and Technical Information of China (English)

    WANG Bin; YANG Yuan-sheng; ZHOU Ji-xue; TONG Wen-hui

    2008-01-01

    The effects of pulsed magnetic field on the solidified microstructure of an AZ91D magnesium alloy were investigated. The experimental results show that the remarkable microstructural refinement is achieved when the pulsed magnetic field is applied in the solidification of AZ91D alloy. The average grain size of the as-cast microstructure of AZ91D alloy is refined to 104μm. Besides the grain refinement, the morphology of the primary α-Mg is changed from dendritic to rosette, then to globular shape with changing the parameters of the pulsed magnetic field. The pulsed magnetic field causes melt convection during solidification, which makes the temperature of the whole melt homogenized, and produces an undercooling zone in front of the liquid/solid interface by the magnetic pressure, which makes the nucleation rate increased and big dendrites prohibited. In addition, primary α-Mg dendrites break into fine crystals, resulting in a refined solidification structure of the AZ91D alloy. The Joule heat effect induced in the melt also strengthens the grain refinement effect and spheroidization of dendrite arms.

  9. Structural evaluation of thermocouple probes for 241-AZ-101 waste tank

    International Nuclear Information System (INIS)

    This document reports on the structural analysis of the thermocouple probe to be installed in 241-AZ-101 waste tank. The thermocouple probe is analyzed for normal pump mixing operation and potential earthquake induced loads required by the Hanford Site Design Criteria SDC-4.1

  10. Selectividad de caña de azúcar en bovinos

    Directory of Open Access Journals (Sweden)

    E. M. Aranda

    2009-01-01

    Full Text Available Se condujo este trabajo con el objetivo de conocer la aceptación del forraje de caña de azúcar integral en la dieta con base de pasto para bovinos adultos fistulados en rumen y duodeno estabulados; para ello, se ofreció pasto estrella africana (Cynodon plectostachyus y caña de azúcar (Saccharum officinarum mezclada con 1% de urea a voluntad, por separado. Se midió la composición de los alimentos, consumo de materia seca, pH ruminal y duodenal. Se utilizaron técnicas de la estadística descriptiva, como la media aritmética y error estándar. La proteína, paredes celulares y hemicelulosa fueron mayores para el pasto estrella. El consumo de MS fue de 46.6 y 38.1% para la caña de azúcar y el pasto, respectivamente; el pH ruminal tuvo valores de 7.3, disminuyendo a 6.7 a las 12 h.; y el pH de la digesta duodenal osciló de 3.7 a 4.7. Se concluye que hubo mayor aceptación por la caña de azúcar y el pH ruminal no indica valores que afecten la celulólisis ruminal.

  11. El despojo del patrimonio gallego. Una denuncia de Isaac Díaz Pardo

    OpenAIRE

    Sánchez García, Jesús Ángel; Sobrino Manzanares, María Luisa

    2010-01-01

    Dando continuidad al objetivo de recuperar textos sobre arte gallego inéditos o poco conocidos, en esta ocasión se han seleccionado dos artículos escritos por el multifacético e incansable artista y empresario Isaac Díaz Pardo (Santiago de Compostela, 1920), ambos publicados en la revista Galicia Emigrante.

  12. 75 FR 11939 - DNS Electronics, Chandler, AZ; Notice of Termination of Investigation

    Science.gov (United States)

    2010-03-12

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF LABOR Employment and Training Administration DNS Electronics, Chandler, AZ; Notice of Termination of Investigation... a petition filed on May 27, 2009, by three workers on behalf of workers of DNS Electronics,...

  13. Complete Genome Sequence of the Model Rhizosphere Strain Azospirillum brasilense Az39, Successfully Applied in Agriculture.

    Science.gov (United States)

    Rivera, Diego; Revale, Santiago; Molina, Romina; Gualpa, José; Puente, Mariana; Maroniche, Guillermo; Paris, Gastón; Baker, David; Clavijo, Bernardo; McLay, Kirsten; Spaepen, Stijn; Perticari, Alejandro; Vazquez, Martín; Wisniewski-Dyé, Florence; Watkins, Chris; Martínez-Abarca, Francisco; Vanderleyden, Jos; Cassán, Fabricio

    2014-01-01

    We present the complete genome sequence of Azospirillum brasilense Az39, isolated from wheat roots in the central region of Argentina and used as inoculant in extensive and intensive agriculture during the last four decades. The genome consists of 7.39 Mb, distributed in six replicons: one chromosome, three chromids, and two plasmids. PMID:25059863

  14. Fatigue behavior of magnesium alloy and application in auto steering wheel frame

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The low-cycle fatigue behaviors of AZ91HP-F, AZ91HP-T6, AZ91HP-T4 and AM50HP-F were investigated, and the potential application of AM50HP-F in steering wheel frame was studied. The steering wheel properties were characterized by bend fatigue and tensile testing, and the fatigue fracture was analyzed by SEM. The results show that the fatigue lives of AZ91HP-F and AZ91HP-T6 have little difference by comparing the low-cycles fatigue properties of different heat treatment states. The crack propagation velocity of AZ91HP-T4 is lower than that of AZ91HP-F and AZ91HP-T6. The die casting technological parameters of the magnesium steering wheel have been optimized with the aid of flow-3D software. The tensile testing results of the different part of magnesium steering wheel show that the ultimate tensile strength and elongation in the wheel arm and wheel rim have no difference and the average value are 220 MPa and 5%, respectively. The fracture is in the brittleness mode and the fatigue crack initiates at the outside of the wheel rim.

  15. Dynamic-angle spinning and double rotation of quadrupolar nuclei

    International Nuclear Information System (INIS)

    Nuclear magnetic resonance (NMR) spectroscopy of quadrupolar nuclei is complicated by the coupling of the electric quadrupole moment of the nucleus to local variations in the electric field. The quadrupolar interaction is a useful source of information about local molecular structure in solids, but it tends to broaden resonance lines causing crowding and overlap in NMR spectra. Magic- angle spinning, which is routinely used to produce high resolution spectra of spin-1/2 nuclei like carbon-13 and silicon-29, is incapable of fully narrowing resonances from quadrupolar nuclei when anisotropic second-order quadrupolar interactions are present. Two new sample-spinning techniques are introduced here that completely average the second-order quadrupolar coupling. Narrow resonance lines are obtained and individual resonances from distinct nuclear sites are identified. In dynamic-angle spinning (DAS) a rotor containing a powdered sample is reoriented between discrete angles with respect to high magnetic field. Evolution under anisotropic interactions at the different angles cancels, leaving only the isotropic evolution of the spin system. In the second technique, double rotation (DOR), a small rotor spins within a larger rotor so that the sample traces out a complicated trajectory in space. The relative orientation of the rotors and the orientation of the larger rotor within the magnetic field are selected to average both first- and second-order anisotropic broadening. The theory of quadrupolar interactions, coherent averaging theory, and motional narrowing by sample reorientation are reviewed with emphasis on the chemical shift anisotropy and second-order quadrupolar interactions experienced by half-odd integer spin quadrupolar nuclei. The DAS and DOR techniques are introduced and illustrated with application to common quadrupolar systems such as sodium-23 and oxygen-17 nuclei in solids

  16. Dynamic-angle spinning and double rotation of quadrupolar nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, K.T. (Lawrence Berkeley Lab., CA (United States) California Univ., Berkeley, CA (United States). Dept. of Chemistry)

    1991-07-01

    Nuclear magnetic resonance (NMR) spectroscopy of quadrupolar nuclei is complicated by the coupling of the electric quadrupole moment of the nucleus to local variations in the electric field. The quadrupolar interaction is a useful source of information about local molecular structure in solids, but it tends to broaden resonance lines causing crowding and overlap in NMR spectra. Magic- angle spinning, which is routinely used to produce high resolution spectra of spin-{1/2} nuclei like carbon-13 and silicon-29, is incapable of fully narrowing resonances from quadrupolar nuclei when anisotropic second-order quadrupolar interactions are present. Two new sample-spinning techniques are introduced here that completely average the second-order quadrupolar coupling. Narrow resonance lines are obtained and individual resonances from distinct nuclear sites are identified. In dynamic-angle spinning (DAS) a rotor containing a powdered sample is reoriented between discrete angles with respect to high magnetic field. Evolution under anisotropic interactions at the different angles cancels, leaving only the isotropic evolution of the spin system. In the second technique, double rotation (DOR), a small rotor spins within a larger rotor so that the sample traces out a complicated trajectory in space. The relative orientation of the rotors and the orientation of the larger rotor within the magnetic field are selected to average both first- and second-order anisotropic broadening. The theory of quadrupolar interactions, coherent averaging theory, and motional narrowing by sample reorientation are reviewed with emphasis on the chemical shift anisotropy and second-order quadrupolar interactions experienced by half-odd integer spin quadrupolar nuclei. The DAS and DOR techniques are introduced and illustrated with application to common quadrupolar systems such as sodium-23 and oxygen-17 nuclei in solids.

  17. Characterization of the first core sample of neutralized current acid waste from double-shell tank 101-AZ

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, M E; Scheele, R D; Tingey, J M

    1989-09-01

    In FY 1989, Westinghouse Hanford Company (WHC) successfully obtained four core samples (totaling seven segments) of neutralized current acid waste (NCAW) from double-shell tanks (DSTs) 101-AZ and 102-AZ. A segment was a 19-in.-long and 1-in.-diameter cylindrical sample of waste. A core sample consisted of enough 19-in.-long segments to obtain the waste of interest. Three core samples were obtained from DST 101-AZ and one core sample from DST 102-AZ. Two DST 101-AZ core samples consisted of two segments per core, and the third core sample consisted of only one segment. The third core consisted of the solids from the bottom of the tank and was used to determine the relative abrasiveness of this NCAW. The DST 102-AZ core sample consisted of two segments. The core samples were transported to the Pacific Northwest Laboratory (PNL), where the waste was extruded from its sampler and extensively characterized. A characterization plan was followed that simulated the processing of the NCAW samples through retrieval, pretreatment and vitrification process steps. Physical, rheological, chemical and radiochemical properties were measured throughout the process steps. The characterization of the first core sample from DST 101-AZ was completed, and the results are provided in this report. The results for the other core characterizations will be reported in future reports. 3 refs., 13 figs., 10 tabs.

  18. Neutron Resonances in Systems of Few Nuclei and Their Possible Role in Radiation of Overdense Stars

    International Nuclear Information System (INIS)

    Exact analytical solutions of three- and four-body systems made of one light particle and other heavy particles have been obtained in the model of Born-Oppenheimer approximation with two-body separable interactions. In the case of neutron scattering on a subsystem of few fixed nuclei the appearance of new resonance quantum states has been shown as well as their dependence on distances between heavy nuclei. The applications of new phenomena to overdense stars radiation are considered. (author)

  19. Covariant density functional theory for exotic nuclei near the neutron drip-line

    International Nuclear Information System (INIS)

    The covariant density functional theory with a few number of parameters allows a very successful description of ground-state and excited-state properties for nuclei all over the nuclear chart. The recent progress on the covariant density functional theory and its applications for nuclear structure and astrophysics as well as extensions by the Beijing group and collaborators are summarized. In particular, the halos in exotic nuclei are discussed in details.

  20. Tank 241-AZ-101 criticality assessment resulting from pump jet mixing: Sludge mixing simulation

    International Nuclear Information System (INIS)

    Tank 241-AZ-101 (AZ-101) is one of 28 double-shell tanks located in the AZ farm in the Hanford Site's 200 East Area. The tank contains a significant quantity of fissile materials, including an estimated 9.782 kg of plutonium. Before beginning jet pump mixing for mitigative purposes, the operations must be evaluated to demonstrate that they will be subcritical under both normal and credible abnormal conditions. The main objective of this study was to address a concern about whether two 300-hp pumps with four rotating 18.3-m/s (60-ft/s) jets can concentrate plutonium in their pump housings during mixer pump operation and cause a criticality. The three-dimensional simulation was performed with the time-varying TEMPEST code to determine how much the pump jet mixing of Tank AZ-101 will concentrate plutonium in the pump housing. The AZ-101 model predicted that the total amount of plutonium within the pump housing peaks at 75 g at 10 simulation seconds and decreases to less than 10 g at four minutes. The plutonium concentration in the entire pump housing peaks at 0.60 g/L at 10 simulation seconds and is reduced to below 0.1 g/L after four minutes. Since the minimum critical concentration of plutonium is 2.6 g/L, and the minimum critical plutonium mass under idealized plutonium-water conditions is 520 g, these predicted maximums in the pump housing are much lower than the minimum plutonium conditions needed to reach a criticality level. The initial plutonium maximum of 1.88 g/L still results in safety factor of 4.3 in the pump housing during the pump jet mixing operation