WorldWideScience

Sample records for sous chargement biaxial

  1. Évolution de la surface de plasticité sous chargement biaxial dans un acier inoxydable duplex

    Science.gov (United States)

    Aubin, V.; Quaegebeur, P.; Degallaix, S.

    2002-12-01

    Nous proposons une méthodologie de mesure automatique de la surface de plasticité pendant des chargements cycliques biaxiaux. La surface de plasticité est mesurée de manière discrète avec un faible offset de déformation plastique (2 10^{-5}) et des paramètres de mesure optimisés. La méthode est appliquée à un acier inoxydable duplex soumis à un trajet de chargement non-proportionnel. Les résultats montrent une distorsion et une translation de la surface de plasticité sans changement de taille. La méthode présentée permet également de vérifier la normalité de la vitesse d'écoulement plastique par rapport à la surface de plasticité.

  2. Cyclic plasticity of an austenitic-ferritic stainless steel under biaxial non proportional loading; Plasticite cyclique d'un acier inoxydable austeno-ferritique sous chargement biaxial non-proportionnel

    Energy Technology Data Exchange (ETDEWEB)

    Aubin, V

    2001-11-15

    Austenitic-ferritic stainless steels are supplied since about 30 years only, so they are yet not well-known. Their behaviour in cyclic plasticity was studied under uniaxial loading but not under multiaxial loading, whereas only a thorough knowledge of the phenomena influencing the mechanical behaviour of a material enables to simulate and predict accurately its behaviour in a structure. This work aims to study and model the behaviour of a duplex stainless steel under cyclic biaxial loading. A three step method was adopted. A set of tension-torsion tests on tubular specimen was first defined. We studied the equivalence between loading directions, and then the influence of loading path and loading history on the stress response of the material. Results showed that duplex stainless steel shows an extra-hardening under non proportional loading and that its behaviour depends on previous loading. Then, in order to analyse the results obtained during this first experimental stage, the yield surface was measured at different times during cyclic loading of the same kind. A very small plastic strain offset (2*10{sup -5}) was used in order not to disturb the yield surface measured. The alteration of isotropic and kinematic hardening variables were deduced from these measures. Finally, three phenomenological constitutive laws were identified with the experimental set. We focused our interest on the simulation of stabilized stress levels and on the simulation of the cyclic hardening/softening behaviour. The comparison between experimental and numerical results enabled the testing of the relevance of these models. (authors)

  3. Étude expérimentale du comportement cyclique d'un acier du type 316 L sous chargement multiaxial complexe en traction-torsion-pressions interne et externe

    Science.gov (United States)

    Bocher, L.; Delobelle, P.

    1997-09-01

    are very rich in informations and lead to classify the different types of loading, with two or three cyclic components, with respect to the observed supplementary hardening. This classification was established as follows: i) The in-phase tests with two or three components (δ = \\varphi = 0^circ); no supplementary hardening is observed. ii) The tension-pressure tests such as r_1 = 1, \\varphi = 90^circ and r_1 = - 1, \\varphi = 60^circ, the hardening is slightly inferior to that of tension-torsion tests. iii) The tension-torsion tests such as r_2 = 1 and δ = 90^circ, where a substantial additionnal hardening takes place. iv) The tension-torsion-pressure tests where the three components are strongly shifted, namely: r_1 = r_2 = 1, δ = 90^circ and \\varphi = 60^circ, and r_2 = 1, r_1 = -1, δ = 41.4^circ and \\varphi = 82.8^circ. The hardening is slightly superior to the one recorded in tension-torsion. A more thorough study is in preparation which considers all the possible combinations in tension-torsion-pressures, and will be performed on the same material. The early results tend to validate the observations presented in this article. Cette étude réside dans la détermination expérimentale du comportement à la température ambiante de l'acier inoxydable 316 L sous chargement cyclique non proportionnel en traction-torsion-pressions interne et externe. Les deux ou trois déformations sinusoïdales appliquées sont soit en phase, soit hors-phase et l'on étudie l'amplitude du durcissement supplémentaire en fonction du degré de multiaxialité. On présente quelques boucles stabilisées typiques. Par rapport au durcissement supplémentaire maximal, les différents essais peuvent être classés comme suit: essais en phase (pas de durcissement supplémentaire), essais de traction-pressions hors-phase, essais de traction-torsion hors phase et essais de traction-torsion-pressions avec déphasages conséquents.

  4. Comportement en flexion des bétons fibrés sous chargement cyclique

    Directory of Open Access Journals (Sweden)

    Boulekbache Bensaid

    2014-04-01

    Full Text Available Ce papier présente les résultats d’une étude expérimentale sur le comportement en flexion des bétons de fibres métalliques. On étudie l’effet de la rhéologie du béton sur l’orientation des fibres et l’influence de l’orientation sur les propriétés mécaniques. La rigidité de l’ancrage des fibres étudiée par les essais cycliques est liée aux caractéristiques rhéologiques et mécaniques de la matrice. Les résultats montrent que la fluidité des bétons est un paramètre essentiel de l’orientation des fibres. Dès lors que l’on obtient une orientation dans le sens de l’efficacité mécanique, la résistance à la flexion est nettement améliorée.

  5. Recherche de propriétés de fatigue dommages et dilatance de roche sous chargement cyclique discontinu

    OpenAIRE

    Fan , Jinyang

    2017-01-01

    Since the salt cavern storage of natural gas and compressed air plays a critical role in ensuring the energy supply and adjusting the seasonal imbalance of power, China government has been constructing numerous new storages in recent years. Because of the seasonal of the seasonal variations of the gas/air pressure, the storages undergo cyclic loading, which causes rock fatigue and induces the associated safety and environmental hazards. The investigation of the discontinuous fatigue of salt u...

  6. Composes inter-halogenes sous pression: etude des transformations structurales dans le monobromure d'iode sous forme dense

    Science.gov (United States)

    Bouchard, Alexandre

    La famille des composes halogenes et inter-halogenes representent des solides moleculaires adoptant des phases denses communes avec des solides moleculaires diatomiques comme l'azote et l'hydrogene. Parmi les transformations structurales et electroniques induites sous haute pression et observees dans ces solides, on note, entre autres, la dissociation moleculaire et la metallisation. De plus, l'etude des phases denses de l'iode a permis recemment l'observation d'une structure cristalline possedant une modulation dite incommensurable, c'est-a-dire une modulation possedant une periodicite differente de celle de la structure cristalline, jetant ainsi une lumiere nouvelle sur le processus de dissociation moleculaire dans les solides halogenes. Dans ce memoire, on propose d'etudier les changements structuraux dans monobromure d'iode (IBr), un compose inter-halogene possedant des proprietes structurales semblables a celles de deux composes halogenes, soit l'iode (I 2) et le brome (Br2) sous leur forme solide. Des experiences de diffraction des rayons X de poudres en utilisant un rayonnement synchrotron ont ete realisees a temperature ambiante sur l'IBr en variant la pression jusqu'aux environs de 60 GPa. La nature chimique particuliere du compose IBr a necessite la mise au point de techniques de chargement d'echantillon destinees a preserver l'integrite chimique de la substance utilisee. On rapporte egalement l'observation d'une phase de l'IBr presentant une modulation incommensurable. Les phases observees dans l'IBr permettent d'etablir des paralleles avec les phases denses rapportees dans I2 et Br2 par le biais d'un modele phenomenologique decrivant la sequence structurale des solides halogenes sous forme condensee.

  7. Biaxial Creep Specimen Fabrication

    International Nuclear Information System (INIS)

    JL Bump; RF Luther

    2006-01-01

    This report documents the results of the weld development and abbreviated weld qualification efforts performed by Pacific Northwest National Laboratory (PNNL) for refractory metal and superalloy biaxial creep specimens. Biaxial creep specimens were to be assembled, electron beam welded, laser-seal welded, and pressurized at PNNL for both in-pile (JOYO reactor, O-arai, Japan) and out-of-pile creep testing. The objective of this test campaign was to evaluate the creep behavior of primary cladding and structural alloys under consideration for the Prometheus space reactor. PNNL successfully developed electron beam weld parameters for six of these materials prior to the termination of the Naval Reactors program effort to deliver a space reactor for Project Prometheus. These materials were FS-85, ASTAR-811C, T-111, Alloy 617, Haynes 230, and Nirnonic PE16. Early termination of the NR space program precluded the development of laser welding parameters for post-pressurization seal weldments

  8. Biaxial Creep Specimen Fabrication

    Energy Technology Data Exchange (ETDEWEB)

    JL Bump; RF Luther

    2006-02-09

    This report documents the results of the weld development and abbreviated weld qualification efforts performed by Pacific Northwest National Laboratory (PNNL) for refractory metal and superalloy biaxial creep specimens. Biaxial creep specimens were to be assembled, electron beam welded, laser-seal welded, and pressurized at PNNL for both in-pile (JOYO reactor, O-arai, Japan) and out-of-pile creep testing. The objective of this test campaign was to evaluate the creep behavior of primary cladding and structural alloys under consideration for the Prometheus space reactor. PNNL successfully developed electron beam weld parameters for six of these materials prior to the termination of the Naval Reactors program effort to deliver a space reactor for Project Prometheus. These materials were FS-85, ASTAR-811C, T-111, Alloy 617, Haynes 230, and Nirnonic PE16. Early termination of the NR space program precluded the development of laser welding parameters for post-pressurization seal weldments.

  9. Biaxial magnetic grain alignment

    International Nuclear Information System (INIS)

    Staines, M.; Genoud, J.-Y.; Mawdsley, A.; Manojlovic, V.

    2000-01-01

    Full text: We describe a dynamic magnetic grain alignment technique which can be used to produce YBCO thick films with a high degree of biaxial texture. The technique is, however, generally applicable to preparing ceramics or composite materials from granular materials with orthorhombic or lower crystal symmetry and is therefore not restricted to superconducting applications. Because magnetic alignment is a bulk effect, textured substrates are not required, unlike epitaxial coated tape processes such as RABiTS. We have used the technique to produce thick films of Y-247 on untextured silver substrates. After processing to Y-123 the films show a clear enhancement of critical current density relative to identically prepared untextured or uniaxially textured samples. We describe procedures for preparing materials using magnetic biaxial grain alignment with the emphasis on alignment in epoxy, which can give extremely high texture. X-ray rocking curves with FWHM of as little as 1-2 degrees have been measured

  10. Biaxial vent extruder

    International Nuclear Information System (INIS)

    Idemoto, A.; Maki, Y.; Oda, N.

    1981-01-01

    A biaxial vent extruder is described for processing of slurry-like waste fluids or radioactive waste fluids which have a hopper cylinger, a solidifying substance port and a solidified substance port. A plurality of vent cylinders each having a vent port are provided with a plunger type scraper. An extruding cylinder having a single opening for a main screw is connected to the assembled vent cylinders. The main screw extends to the upstream end of the extruding cylinder and a sub-screw extends to the extruding cylinder. The screws each having a full flight engaging the other and a set of rings are mounted on the screws near the respective vent port inlets. The screws are rotated in different directions and inwardly with respect to the vent ports. Rotors may be mounted on the screws to break down solid particles

  11. Biaxial stretching of film principles and applications

    CERN Document Server

    Demeuse, M T

    2011-01-01

    Biaxial (having two axes) stretching of film is used for a range of applications and is the primary manufacturing process by which products are produced for the food packaging industry. Biaxial stretching of film: principles and applications provides an overview of the manufacturing processes and range of applications for biaxially stretched films. Part one reviews the fundamental principles of biaxial stretching. After an introductory chapter which defines terms, chapters discuss equipment design and requirements, laboratory evaluations, biaxial film structures and typical industrial processes for the biaxial orientation of films. Additional topics include post production processing of biaxially stretched films, the stress-strain behaviour of poly(ethylene terephthalate) and academic investigations of biaxially stretched films. Part two investigates the applications of biaxial films including fresh cut produce, snack packaging and product labelling. A final chapter investigates potential future trends for bi...

  12. Biaxial Stress Tests of Plain Concrete

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.K.; Cho, M.S.; Song, Y.C. [Korea Electric Power Research Institute, Taejon (Korea)

    2001-07-01

    Containment concrete specimens(4000, 5000psi) were tested under biaxial stress and presented basic physical properties and biaxial failure envelops for the concrete specimens. Failure behaviors of concrete under biaxial stress were assessed with stress-strain responses and failure modes. Here provided real test data to develop nonlinear finite element concrete models. (author). 15 refs., 46 figs., 4 tabs.

  13. Le cerveau sous effet placebo

    OpenAIRE

    Touzet , Claude

    2017-01-01

    International audience; Comment le fait de croire qu’on nous injecte de la morphine (alors qu’il s’agit de sérum physiologique) peut-il faire disparaître la douleur ? Investigation sur le cerveau sous placebo.

  14. A damage model of Zr {alpha} under cyclic loading at 200 degree Celsius; Modelisation de l`endommagement du Zr {alpha} sous chargement cyclique a 200 deg C

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, C.; Drubay, B. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. de Mecanique et de Technologie; Cailletaud, G. [Ecole Nationale Superieure des Mines, 75 - Paris (France); Mottot, M. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Direction des Technologies Avancees

    1994-12-31

    A damage model for anticipating zirconium {alpha} test-piece rupture under cyclic solicitations at 200 degree Celsius is presented. The article is divided into three parts : an experimental approach, the damage model presentation and the application of this model. (O.L.). 10 refs., 7 figs., 4 tabs.

  15. Assessment of subcriticality during PWR-type reactor refueling; Evaluation de la sous-criticite lors des operations de chargement d'un reacteur nucleaire REP

    Energy Technology Data Exchange (ETDEWEB)

    Verdier, A

    2005-04-15

    During the core loading period of a PWR, any fuel assembly misplacements may significantly reduce the existing criticality margin. The Dampierre 4-18 event showed the present monitoring based on the variations of the outside-core detector counting rate cannot detect such misplacements. In order to circumvent that, a more detailed analysis of the available signal was done. We particularly focused on the neutronic noise analysis methods such as MSM (modified source multiplication), MSA (amplified source multiplication), Rossi-{alpha} and Feynman-{alpha} methods. The experimental part of our work was dedicated to the application of those methods to a research reactor. Finally, our results showed that those methods cannot be used with the present PWR instrumentation. Various detector positions were then studied using Monte Carlo calculations capable of following the neutron origin. Our results showed that the present technology does not allow us to use any solution based on neutron detection for monitoring core loading. (author)

  16. Lifetime prediction of structures submitted to thermal fatigue loadings; Prediction de duree de vie de structures sous chargement de fatigue thermique

    Energy Technology Data Exchange (ETDEWEB)

    Amiable, S

    2006-01-15

    The aim of this work is to predict the lifetime of structures submitted to thermal fatigue loadings. This work lies within the studies undertaken by the CEA on the thermal fatigue problems from the french reactor of Civaux. In particular we study the SPLASH test: a specimen is heated continuously and cyclically cooled down by a water spray. This loading generates important temperature gradients in space and time and leads to the initiation and the propagation of a crack network. We propose a new thermo-mechanical model to simulate the SPLASH experiment and we propose a new fatigue criterion to predict the lifetime of the SPLASH specimen. We propose and compare several numerical models with various complexity to estimate the mechanical response of the SPLASH specimen. The practical implications of this work are the reevaluation of the hypothesis used in the French code RCC, which are used to simulate thermal shock and to interpret the results in terms of fatigue. This work leads to new perspectives on the mechanical interpretation of the fatigue criterion. (author)

  17. Characteristics definition and optimisation of an integrated electromechanical battery under cyclic loading; Caracterisation et optimisation d'une batterie electromecanique sous chargement cyclique

    Energy Technology Data Exchange (ETDEWEB)

    Kerzreho, C.

    2002-01-15

    This work takes place into a multidisciplinary project, gathering mechanical and electromechanical specialists, with the aim to design a 3 kWh household electromechanical battery module. The energy is stored as kinetic one in a flywheel. The main characteristics of this battery are a high yield, a long life duration and a minimal discharge time over one hour. At a low cost, it could be used in conjunction with alternative electric sources and to secure and regulate home current supplies and consumption. Following a literature review of the available technologies, the flywheel similitude properties are demonstrated and capabilities design coefficients are defined taking into account the stress cycles. In order to define criterions to choose the flywheel material and geometry, the results are applied to the major literatures configurations including metals, composites or ceramics. They are brought together as graphical maps and, using optimal solution surfaces, they show the compromises between the design criterions such as specific energy, energy density, maximal rotational velocity and cost. A single suited structure is then defined which integrates into the flywheel some parts of the motor-generator and of the magnetic bearings. A global design process is conducted taking into account the specific properties and the interactions between the components. The geometry of the motor-generator rotor is optimised then, improving the battery performances. The feasibility of an auto-fitting process is proposed showing that endurance limit depends on flywheel slenderness. The build prototype is finally presented. (author)

  18. Biaxiality of chiral liquid crystals

    International Nuclear Information System (INIS)

    Longa, L.; Trebin, H.R.; Fink, W.

    1993-10-01

    Using extended deGennes-Ginzburg-Landau free energy expansion in terms of the anisotropic part of the dielectric tensor field Q αβ (χ) a connection between the phase biaxiality and the stability of various chiral liquid crystalline phases is studied. In particular the cholesteric phase, the cubic Blue Phases and the phases characterized by an icosahedral space group symmetry are analysed in detail. Also a general question concerning the applicability of the mean-field approximation in describing the chiral phases is addressed. By an extensive study of the model over a wide range of the parameters a new class of phenomena, not present in the original deGennes-Ginzburg-Landau model, has been found. These include: a) re-entrant phase transitions between the cholesteric and the cubic blue phases and b) the existence of distinct phases of the same symmetry but of different biaxialities. The phase biaxiality serves here as an extra scalar order parameter. Furthermore, it has been shown that due to the presence of the competing bulk terms in the free energy, the stable phases may acquire a large degree of biaxiality, also in liquid crystalline materials composed of effectively uniaxial molecules. A study of icosahedral space group symmetries gives a partial answer to the question as to whether an icosahedral quasicrystalline liquid could be stabilized in liquid crystals. Although, in general, the stability of icosahedral structures could be enhanced by the extra terms in the free energy no absolutely stable icosahedral phase has been found. (author). 16 refs, 3 figs, 1 tab

  19. Biaxial fatigue of metals the present understanding

    CERN Document Server

    Schijve, Jaap

    2016-01-01

    Problems of fatigue under multiaxial fatigue loads have been addressed in a very large number of research publications. The present publication is primarily a survey of biaxial fatigue under constant amplitude loading on metal specimens. It starts with the physical understanding of the fatigue phenomenon under biaxial fatigue loads. Various types of proportional and non-proportional biaxial fatigue loads and biaxial stress distributions in a material are specified. Attention is paid to the fatigue limit, crack nucleation, initial micro crack growth and subsequent macro-crack in different modes of crack growth. The interference between the upper and lower surfaces of a fatigue crack is discussed. Possibilities for predictions of biaxial fatigue properties are analysed with reference to the similarity concept. The significance of the present understanding for structural design problems is considered. The book is completed with a summary of major observations.

  20. Stabilisation problem in biaxial platform

    Directory of Open Access Journals (Sweden)

    Lindner Tymoteusz

    2016-12-01

    Full Text Available The article describes investigation of rolling ball stabilization problem on a biaxial platform. The aim of the control system proposed here is to stabilize ball moving on a plane in equilibrium point. The authors proposed a control algorithm based on cascade PID and they compared it with another control method. The article shows the results of the accuracy of ball stabilization and influence of applied filter on the signal waveform. The application used to detect the ball position measured by digital camera has been written using a cross platform .Net wrapper to the OpenCV image processing library - EmguCV. The authors used the bipolar stepper motor with dedicated electronic controller. The data between the computer and the designed controller are sent with use of the RS232 standard. The control stand is based on ATmega series microcontroller.

  1. Stabilisation problem in biaxial platform

    Science.gov (United States)

    Lindner, Tymoteusz; Rybarczyk, Dominik; Wyrwał, Daniel

    2016-12-01

    The article describes investigation of rolling ball stabilization problem on a biaxial platform. The aim of the control system proposed here is to stabilize ball moving on a plane in equilibrium point. The authors proposed a control algorithm based on cascade PID and they compared it with another control method. The article shows the results of the accuracy of ball stabilization and influence of applied filter on the signal waveform. The application used to detect the ball position measured by digital camera has been written using a cross platform .Net wrapper to the OpenCV image processing library - EmguCV. The authors used the bipolar stepper motor with dedicated electronic controller. The data between the computer and the designed controller are sent with use of the RS232 standard. The control stand is based on ATmega series microcontroller.

  2. Biaxial Loading Tests for steel containment vessel

    Energy Technology Data Exchange (ETDEWEB)

    Miyagawa, T. [Nuclear Power Engineering Corp., Tokyo (Japan); Wright, D.J.; Arai, S.

    1999-07-01

    The Nuclear Power Engineering Corporation (NUPEC) has conducted a 1/10 scale of the steel containment vessel (SCV) test for the understanding of ultimate structural behavior beyond the design pressure condition. Biaxial Loading Tests were supporting tests for the 1/10 scale SCV model to evaluate the method of estimating failure conditions of thin steel plates under biaxial loading conditions. The tentative material models of SGV480 and SPV490 were obtained. And the behavior of SGV480 and SPV490 thin steel plates under biaxial loading conditions could be well simulated by FE-Analyses with the tentative material models and Mises constitutive law. This paper describes the results and the evaluations of these tests. (author)

  3. Biaxial Loading Tests for steel containment vessel

    International Nuclear Information System (INIS)

    Miyagawa, T.; Wright, D.J.; Arai, S.

    1999-01-01

    The Nuclear Power Engineering Corporation (NUPEC) has conducted a 1/10 scale of the steel containment vessel (SCV) test for the understanding of ultimate structural behavior beyond the design pressure condition. Biaxial Loading Tests were supporting tests for the 1/10 scale SCV model to evaluate the method of estimating failure conditions of thin steel plates under biaxial loading conditions. The tentative material models of SGV480 and SPV490 were obtained. And the behavior of SGV480 and SPV490 thin steel plates under biaxial loading conditions could be well simulated by FE-Analyses with the tentative material models and Mises constitutive law. This paper describes the results and the evaluations of these tests. (author)

  4. Ray-optics analysis of inhomogeneous biaxially anisotropic media

    NARCIS (Netherlands)

    Sluijter, M.; De Boer, D.K.G.; Urbach, H.P.

    2009-01-01

    Firm evidence of the biaxial nematic phase in liquid crystals, not induced by a magnetic or electric field, has been established only recently. The discovery of these biaxially anisotropic liquid crystals has opened up new areas of both fundamental and applied research. The advances in biaxial

  5. SOUS LES PAVÉS: LA PLAGE!

    DEFF Research Database (Denmark)

    Clemmensen, Thomas Juel

    2017-01-01

    kunstnerbevægelse situationisterne brugte parolen sous les pavés: la plage! blev stranden associeret med det frie naturlige rum i kontrast til den brolagte gade, der repræsenterede samfundets undertrykkende orden. Men udtrykket kan samtidig minde os om geologiens allestedsnærværende karakter. Geologien findes lige...

  6. Analysis of Biaxially Stressed Bridge Deck Plates

    DEFF Research Database (Denmark)

    Jönsson, Jeppe; Bondum, Tommi Højer

    2012-01-01

    The ultimate state analysis of bridge deck plates at the intersection zone between main girders and transverse beams is complicated by biaxial membrane stresses, which may be in compression or tension in either direction depending on the bridge configuration and the specific location. This paper...

  7. Engineering piezoresistivity using biaxially strained silicon

    DEFF Research Database (Denmark)

    Pedersen, Jesper Goor; Richter, Jacob; Brandbyge, Mads

    2008-01-01

    of the piezocoefficient on temperature and dopant density is altered qualitatively for strained silicon. In particular, we find that a vanishing temperature coefficient may result for silicon with grown-in biaxial tensile strain. These results suggest that strained silicon may be used to engineer the iezoresistivity...

  8. Clichy-sous-Bois (France) operation

    Energy Technology Data Exchange (ETDEWEB)

    Dechamp, A

    1984-09-01

    The geothermal plant of Clichy-sous-Bois has been operating for 2 years and covers the needs of 3,400 equivalent-dwellings, including a sport-hall, 2 schools, the town-hall and 7 low-cost groups of flats. Geothermal energy covers 65% of the energy yearly global consumption for heating and sanitary hot water, i.e. 35,151 MWh. Thus, 3,195 TOE are saved each year. In December, 1979, the town of Clichy-sous-bois delegated their sponsorship to the Societe d'equipement et d'amenagement du territoire du departement de la Seine-Saint-Denis - SODETAT 93 for the realization of the geothermal operation. The production and injection wells were drilled between July and September, 1981. The Dogger aquifer was encountered at 1,800 m deep, with a temperature of 70,8/sup 0/C and an exploitation yield of 200m/sup 3//h. Surface works started in March 1982 and were completed in November of the same year. Apart from the geothermal power plant, the network comprises 11 exchange substations and a distribution network of 2,700 m long with 7,000 m of underground pipes. This plant is exploited by the Compagnie francaise d'exploitation thermique (COFRETH) within the framework of a farmout contract for 20 years, including: production, transportation and public distribution of geothermal heat all over the city of Clichy-sous-Bois.

  9. Biaxial crystal-based optical tweezers

    DEFF Research Database (Denmark)

    Angelsky, Oleg V.; Maksimyak, Andrew P.; Maksimyak, Peter P.

    2010-01-01

    We suggest an optical tweezer setup based on an optically biaxial crystal. To control movements of opaque particles, we use shifts. The results of experimental studies are reported which are concerned with this laser tweezer setup. We demonstrate a movement of microparticles of toner using...... a singular-optical trap, rotation of particles due to orbital angular momentum of the field, and converging or diverging of two different traps when changing transmission plane of polariser at the input of our polarisation interferometer....

  10. Implantable biaxial piezoresistive accelerometer for sensorimotor control.

    Science.gov (United States)

    Zou, Qiang; Tan, Wei; Sok Kim, Eun; Singh, Jasspreet; Loeb, Gerald E

    2004-01-01

    This paper describes the design, fabrication and test results of a novel biaxial piezoresistive accelerometer and its incorporation into a miniature neuromuscular stimulator called a BION. Because of its highly symmetric twin mass structure, the X and Z axis acceleration can be measured at the same time and the cross axis sensitivity can be minimized by proper piezoresistor design. The X and Z axis sensitivities of the biaxial accelerometer are 0.10 mV/g/V and 1.40 mV/g/V, respectively, which are further increased to 0.65 mV/g/V and 2.40 mV/g/V, respectively, with extra silicon mass added to the proof mass. The cross-axis sensitivity is less than 3.3% among X, Y and Z-axis. An orientation tracking method for human segments by measuring every joint angle is also discussed in this paper. Joint angles can be obtained by processing the outputs of a pair of biaxial accelerometers (placed very close to the joint axis on the adjacent limb links), without having to integrate acceleration or velocity signals, thereby avoiding errors due to offsets and drift.

  11. Biaxial testing for fabrics and foils optimizing devices and procedures

    CERN Document Server

    Beccarelli, Paolo

    2015-01-01

    This book offers a well-structured, critical review of current design practice for tensioned membrane structures, including a detailed analysis of the experimental data required and critical issues relating to the lack of a set of design codes and testing procedures. The technical requirements for biaxial testing equipment are analyzed in detail, and aspects that need to be considered when developing biaxial testing procedures are emphasized. The analysis is supported by the results of a round-robin exercise comparing biaxial testing machines that involved four of the main research laboratories in the field. The biaxial testing devices and procedures presently used in Europe are extensively discussed, and information is provided on the design and implementation of a biaxial testing rig for architectural fabrics at Politecnico di Milano, which represents a benchmark in the field. The significance of the most recent developments in biaxial testing is also explored.

  12. Biaxial Testing of 2195 Aluminum Lithium Alloy Using Cruciform Specimens

    Science.gov (United States)

    Johnston, W. M.; Pollock, W. D.; Dawicke, D. S.; Wagner, John A. (Technical Monitor)

    2002-01-01

    A cruciform biaxial test specimen was used to test the effect of biaxial load on the yield of aluminum-lithium alloy 2195. Fifteen cruciform specimens were tested from 2 thicknesses of 2195-T8 plate, 0.45 in. and 1.75 in. These results were compared to the results from uniaxial tensile tests of the same alloy, and cruciform biaxial tests of aluminum alloy 2219-T87.

  13. Radiculoplexopathie, anticorps anti Yo et cancer ovarien sous ...

    African Journals Online (AJOL)

    Les radiculo-plexopathies au cours des cancers sont le plus souvent d'origine métastatique. Leur origine dysimmune est rare. Nous rapportons un cas de radiculoplexopathie d'évolution favorable sous traitement immunomodulateur, survenue chez une patiente porteuse d'un carcinome ovarien bilatéral sous ...

  14. Biaxially textured articles formed by powder metallurgy

    Science.gov (United States)

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-08-05

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of ternary mixtures consisting of: Ni powder, Cu powder, and Al powder, Ni powder, Cr powder, and Al powder; Ni powder, W powder and Al powder; Ni powder, V powder, and Al powder; Ni powder, Mo powder, and Al powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100} orientation texture; and further having a Curie temperature less than that of pure Ni.

  15. Biaxially textured articles formed by powder metallurgy

    Science.gov (United States)

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-07-29

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100} orientation texture; and further having a Curie temperature less than that of pure Ni.

  16. Biaxially textured articles formed by power metallurgy

    Science.gov (United States)

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-08-26

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100} orientation texture; and further having a Curie temperature less than that of pure Ni.

  17. Palatability of sous vide processed chicken breast.

    Science.gov (United States)

    Turner, B E; Larick, D K

    1996-08-01

    The influences of brine composition, internal temperature, heating rate, and storage periods up to 28 d on flavor, texture, and color of sous vide processed chicken breast were evaluated. Pectoralis major muscles containing water and sodium chloride, with or without sodium lactate, were browned and vacuum packaged. Sous vide processing was by fast or slow heating to an internal temperature of 77 or 94 C. Product was evaluated after 0, 14, and 28 d storage at 4 C. Quality was evaluated by gas chromatographic analyses of flavor volatiles, shear, color, and sensory panels. Incorporation of sodium lactate into brine did not influence oxidative stability (as measured by headspace gas chromatography) or sensory warmed-over flavor. Presence of sodium lactate did result in enhanced fresh roasted or meaty and saltiness sensory scores as well as a more yellow color. The more rapid heating rate decreased sulfur-containing compounds and did not influence other volatile concentrations. Products processed to 94 C were less juicy, less tender, and contained higher quantities of alcohols and hydrocarbons than those processed to 77 C. Storage resulted in a decline in fresh roasted or meaty flavor note and an increase in warmed-over flavor note and quantities of alcohols, aldehydes and ketones, hydrocarbons, and total headspace volatiles.

  18. Biaxial behavior of plain concrete of nuclear containment building

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang-Keun E-mail: sklee0806@bcline.com; Song, Young-Chul; Han, Sang-Hoon

    2004-01-01

    To provide biaxial failure behavior characteristics of concrete of a standard Korean nuclear containment building, the concrete specimens with the dimensions of 200 mmx200 mmx60 mm were tested under different biaxial load combinations. The specimens were subjected to biaxial load combinations covering the three regions of compression-compression, compression-tension, nd tension-tension. To avoid a confining effect due to friction in the boundary surface between the concrete specimen and the loading platen, the loading platens with Teflon pads were used. The principal deformations in the specimens were recorded, and the failure modes along with each stress ratio were examined. Based on the strength data, the biaxial ultimate strength envelopes were developed and the biaxial stress-strain responses in three different biaxial loading regions were plotted. The test results indicated hat the concrete strength under equal biaxial compression, f{sub 1}=f{sub 2}, is higher by about 17% on the average than that under the uniaxial compression and the concrete strength under biaxial tension is almost independent of the stress ratio and is similar to that under the uniaxial tension.

  19. Biaxial behavior of plain concrete of nuclear containment building

    International Nuclear Information System (INIS)

    Lee, Sang-Keun; Song, Young-Chul; Han, Sang-Hoon

    2004-01-01

    To provide biaxial failure behavior characteristics of concrete of a standard Korean nuclear containment building, the concrete specimens with the dimensions of 200 mmx200 mmx60 mm were tested under different biaxial load combinations. The specimens were subjected to biaxial load combinations covering the three regions of compression-compression, compression-tension, nd tension-tension. To avoid a confining effect due to friction in the boundary surface between the concrete specimen and the loading platen, the loading platens with Teflon pads were used. The principal deformations in the specimens were recorded, and the failure modes along with each stress ratio were examined. Based on the strength data, the biaxial ultimate strength envelopes were developed and the biaxial stress-strain responses in three different biaxial loading regions were plotted. The test results indicated hat the concrete strength under equal biaxial compression, f 1 =f 2 , is higher by about 17% on the average than that under the uniaxial compression and the concrete strength under biaxial tension is almost independent of the stress ratio and is similar to that under the uniaxial tension

  20. Tambaqui (Colossoma macropomum sous vide: characterization and quality parameters

    Directory of Open Access Journals (Sweden)

    Fabiane de Cássia Pontes Ramos

    2016-02-01

    Full Text Available The objective of this study was to evaluate the microbiological, physical and physico-chemical quality parameters of sous vide preparation of pen-reared tambaqui (Colossoma macropomum. To prepare the tambaqui sous vide, 200 g of fillet, 50 g of basil sauce (1:4 fish fillet:sauce ratio and 10 mL of 5% sodium lactate were used. The product was then vacuum-packaged, pasteurized at 65 ºC for 12.5 min and refrigerated. The presence of Salmonella spp., sulfite-reducing Clostridium and Listeria monocytogenes was not detected in the samples analyzed. The coliform count at 45 ºC and coagulase-positive staphylococci were below the limit (103 permitted by the law in vigor. Water retention capacity and chloride content analyses revealed that the tambaqui fillet differed significantly (P<0.05 from the sous vide because of the addition of basil sauce. The total volatile basic nitrogen (TVB-N and thiobarbituric acid reactive substances (TBARS content of the fillet and sous vide were below the limits established by the law, indicating good quality. The lightness (L* and yellow color (b* of the fillet and the sous vide did not differ significantly (P>0.05, but the red color (a* decreased in the sous vide, which is related to the addition of basil sauce. The chroma (C* and hue angle (ho differed significantly (P<0.05, and the fillet samples were lighter in color, whereas the sous vide was characterized by yellow color. The n-6/n-3 ratios found for the fillet and the sous vide are within the recommended values, which is important for human metabolism. The fillet and sous vide also had high calcium, zinc, magnesium and potassium concentrations. It is concluded that tambaqui sous vide is a good source of nutrients, rich in fatty acids and minerals essential for human health.

  1. Biaxial mechanical tests in zircaloy-4

    International Nuclear Information System (INIS)

    Mintzer, S.R.; Bordoni, R.A.A.; Falcone, J.M.

    1980-01-01

    The texture of the zircaloy-4 tubes used as cladding in nuclear fuel elements determines anisotropy of the mechanical properties. As a consequence, the uniaxial tests to determine the mechanical behaviour of the tubes are incomplete. Furthermore, the cladding in use is subject to creep with a state of biaxial tensions. For this reason it is also important to determine the biaxial mechanical properties. The creep tests were performed by internal pressure for a state of axial to circumferential tensions of 0.5. Among the experimental procedures are described: preparation of the test specimens, pressurizing equipment, and the implementation of a device that permits a permanent register of the deformation. For the non-irradiated Atucha type zircaloy-4 sheaths, experimental curves of circumferential deformation versus time were obtained, in tests at constant pressure and for different values of temperature and pressure. An empirical function was determined to adjust the experimental values for the speed of the circumferential deformation in terms of the initial tension applied, temperature and deformation, and the change of the corresponding parameters in accordance to the range of the tensions. Also the activation energy for creep was determined. (M.E.L.) [es

  2. Lipoblastome de la fosse sous temporale

    Science.gov (United States)

    Najib, Jaafar; Aniba, Khalid; Laghmari, Mehdi; Lmejjati, Mohammed; Ghannane, Houssine; Benali, Said Ait; Ennadam, Hind; Mrabti, Hind; Idrissi, Nadia Cherif

    2014-01-01

    Le lipoblastome est une tumeur bénigne rare, formée d'adypocytes immatures associés à la présence d'une matrice myxoide, de septas fibreux, et d'une architecture lobulaire. Il survient généralement chez le nourrisson et l'enfant. Cette tumeur touche dans la majorité des cas les tissus sous-cutanés des extrémités et du tronc. Elle est extrèmement rare au niveau de la tète et du cou. Un total de moins de 100 cas a été rapporté précédemment dans la littérature. PMID:25918563

  3. Local approach: fracture at high temperature in an austenitic stainless steel submitted to thermomechanical loadings. Calculations and experimental validations; Approche locale: fissuration a haute temperature dans un acier inoxydable austenitique sous chargements thermomecaniques. Simulations numeriques et validations experimentales

    Energy Technology Data Exchange (ETDEWEB)

    Poquillon, D

    1997-10-01

    Usually, for the integrity assessment of defective components, well established rules are used: global approach to fracture. A more fundamental way to deal with these problems is based on the local approach to fracture. In this study, we choose this way and we perform numerical simulations of intergranular crack initiation and intergranular crack propagation. This type of damage can be find in components of fast breeder reactors in 316 L austenitic stainless steel which operate at high temperatures. This study deals with methods coupling partly the behaviour and the damage for crack growth in specimens submitted to various thermomechanical loadings. A new numerical method based on finite element computations and a damage model relying on quantitative observations of grain boundary damage is proposed. Numerical results of crack initiation and growth are compared with a number of experimental data obtained in previous studies. Creep and creep-fatigue crack growth are studied. Various specimen geometries are considered: compact Tension Specimens and axisymmetric notched bars tested under isothermal (600 deg C) conditions and tubular structures containing a circumferential notch tested under thermal shock. Adaptative re-meshing technique and/or node release technique are used and compared. In order to broaden our knowledge on stress triaxiality effects on creep intergranular damage, new experiments are defined and conducted on sharply notched tubular specimens in torsion. These isothermal (600 deg C) Mode II creep tests reveal severe intergranular damage and creep crack initiation. Calculated damage fields at the crack tip are compared with the experimental observations. The good agreement between calculations and experimental data shows the damage criterion used can improve the accuracy of life prediction of components submitted to intergranular creep damage. (author) 200 refs.

  4. Study of the damaging mechanisms of a copper / carbon - carbon composite under thermomechanical loading; Etude des mecanismes d'endommagement d'un assemblage cuivre / composite carbone - carbone sous chargement thermomecanique

    Energy Technology Data Exchange (ETDEWEB)

    Moncel, L

    1999-06-18

    The purpose of this work is to understand and to identify the damaging mechanisms of Carbon-Carbon composite bonded to copper under thermomechanical loading. The study of the composite allowed the development of non-linear models. These ones have been introduced in the finite elements analysis code named CASTEM2000. They have been validated according to a correlation between simulation and mechanical tests on multi-material samples. These tests have also permitted us to better understand the behaviour of the bonding between composite and copper (damaging and fracture modes for different temperatures) under shear and tensile loadings. The damaging mechanisms of the bond under thermomechanical loading have been studied and identified according to microscopic observations on mock-ups which have sustained thermal cycling tests: some cracks appear in the composite, near the bond between the composite and the copper. The correlation between numerical and experimental results have been improved because of the reliability of the composite modelization, the use of residual stresses and the results of the bond mechanical characterization. (author)

  5. Study of the damaging mechanisms of a carbon - carbon composite bonded to copper under thermomechanical loading; Etude des mecanismes d'endommagement d'un assemblage cuivre / composite carbone - carbone sous chargement thermomecanique

    Energy Technology Data Exchange (ETDEWEB)

    Moncel, L

    1999-06-15

    The purpose of this work is to understand and to identify the damaging mechanisms of Carbon-Carbon composite bonded to copper under thermomechanical loading. The study of the composite allowed the development of non-linear models. These ones have been introduced in the finite elements analysis code named CASTEM 2000. They have been validated according to a correlation between simulation and mechanical tests on multi-material samples. These tests have also permitted us to better understand the behaviour of the bonding between composite and copper (damaging and fracture modes for different temperatures) under shear and tensile loadings. The damaging mechanisms of the bond under thermomechanical loading have been studied and identified according to microscopic observations on mock-ups which have sustained thermal cycling tests: some cracks appear in the composite, near the bond between the composite and the copper. The correlation between numerical and experimental results have been improved because of the reliability of the composite modelization, the use of residual stresses and the results of the bond mechanical characterisation. (author)

  6. Study of the initiation and the propagation of cracks under 3D thermal cyclic loading; Etude de l'amorcage et de la propagation des fissures sous chargement thermique cyclique 3D

    Energy Technology Data Exchange (ETDEWEB)

    Ancelet, O

    2005-07-01

    The incident which has occurred on the Civaux power plant has shown the noxiousness of thermal loading and the difficulty to take it into account at design level. The objective of this report is to study the initiation and the propagation of crack under thermal loading. In this aim the CEA has developed a new experiment named FAT3D. The various experiments carried out showed the harmfulness of a thermal loading, which makes it possible to rapidly initiate a network of cracks and to propagate one (or some) cracks through the totally thickness of the component under certain conditions. These experimental results associated with a mechanical analysis put at fault the usual criteria of damage based on the variations of the equivalent strain. In addition, the study of the propagation stage shows the importance of the plasticity which, in the case of a thermal loading, slows down the propagation of the crack. (author)

  7. The Sous Vide Revolution: Coming Full Circle and Beyond

    OpenAIRE

    Hoeche, Ulrich

    2016-01-01

    For the purpose of this research, academic material and online sources were utilised to clarify the meaning of the key term sous vide. The Sous Vide Advisory Committee (1991) says ‘Sous Vide (also known as Cuisine en Papillote) is an interrupted catering system in which raw or par-cooked food is sealed into a vacuumised laminated plastic pouch or container, heat treated by controlled cooking, rapidly cooled and then reheated for service after a period of chilled storage’. According to Herb...

  8. Conductive and robust nitride buffer layers on biaxially textured substrates

    Science.gov (United States)

    Sankar, Sambasivan [Chicago, IL; Goyal, Amit [Knoxville, TN; Barnett, Scott A [Evanston, IL; Kim, Ilwon [Skokie, IL; Kroeger, Donald M [Knoxville, TN

    2009-03-31

    The present invention relates to epitaxial, electrically conducting and mechanically robust, cubic nitride buffer layers deposited epitaxially on biaxially textured substrates such as metals and alloys. The invention comprises of a biaxially textured substrate with epitaxial layers of nitrides. The invention also discloses a method to form such epitaxial layers using a high rate deposition method as well as without the use of forming gases. The invention further comprises epitaxial layers of oxides on the biaxially textured nitride layer. In some embodiments the article further comprises electromagnetic devices which may have superconducting properties.

  9. Biaxial wheel/hub test facility. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, G.; Grubisic, V. [eds.

    2000-07-01

    The 4{sup th} meeting aims to exchange the experience and knowledge of engineers during several presentations and discussions about new developments required for a reliable, time and cost reducing validation of the wheel/hub assembly. Tremendous development of the wheel performance, described by the ratio of the rated load (kg) versus the wheel weight (kg) had taken place during the last 5000 years. Starting from the ratio of 3 for wooden 2-piece-disc-wheels in Mesopotamia it needed nearly 1000 years to increase the ratio to approx 5 at light-weight spoke wheels for fighting carriages, found in the grave of king Tutenchamon in Egypt. Modern light alloy wheels of commercial vehicles reach values up to 160 kg/kg. Additionally the comlex design of the modern systems for cars and commercial vehicles comprising wheel, brake, hub, bearing, spindle and hub carrier, including different materials and their treatment, fasteners, press-fits, require an appropriate testing procedure. The variable loading conditions, caused by operational wheel forces, brake and torque moments including heating, may result in changing tolerances and press-fits during operation and consequently in different damage mechanisms. This can be simulated in the Biaxial Wheel Test Machine, whereby corresponding load programs are necessary. An overview about all biaxial test machines in usage at the end of 1999 is shown in the introduction. The total number is 17 for cars, 7 for commercial vehicles and 1 for trains. The six presentations of this meeting were consequently concentrated on: (a) recommendations for a standardization of load programs of the German Wheel Committee, (b) the simulation of brake and torque events and (c) the possibility for a numerical stress analyses and fatigue life assessment. (orig./AKF)

  10. Behaviour of biaxially restrained concretes under high temperature

    International Nuclear Information System (INIS)

    Thienel, K.-Ch.; Rostasy, F.S.

    1993-01-01

    Under asymmetric biaxial loading the major restraining stresses of concrete made with expanded shale or quarzite aggregates change between both loading axis. Differences between uniaxial and biaxial restraint vanish, if the restraint is normalized with respect to the ultimate strength at ambient temperature of the same stress ratio K. The type of aggregate and the mix proportions do affect the restraining stresses irrespective of the initial stress ratio K 0 . (author)

  11. La base sous-marine de Bordeaux, sous le béton la culture

    Directory of Open Access Journals (Sweden)

    Mathieu Marsan

    2012-06-01

    Full Text Available Active à peine plus d’un an pendant l’Occupation, la base sous-marine de Bordeaux cristallise encore les souvenirs douloureux des heures sombres du Port de la Lune. Le bunker attire pourtant depuis les années 1960 des artistes, cinéastes, plasticiens et musiciens fascinés par l’esprit du lieu. Institutionnalisée au début des années 1990, la base sous-marine devient un espace dédié au nautisme avant d’être consacrée à l’art contemporain au début du XXIe siècle. Aujourd’hui au cœur du projet d’aménagement des bassins à flot du quartier de Bacalan, la base sous-marine questionne et intrigue ses visiteurs sur son passé, mais aussi – et surtout – sur son avenir.Build during the German occupation, the submarine base of Bordeaux active during hardly more than a year still crystallizes the painful memories of the dark hours of the « Port de la Lune ». Nevertheless, the bunker attracts artists, film-makers, visual artists and musicians fascinated by the spirit of the place since the 1960’s. Institutionalized at the beginning of 1990’s, the submarine base became a space dedicated to the yachting before contemporary art at the beginning of the XXIth century. Nowadays at the heart of the project of redevelopment of the wet docks in the urban area of Bacalan, the submarine base questions and intrigues its visitors on its past, but also – and especially – on its future.

  12. Fertilité des sols agricoles sous vigne et sous blé de la région de ...

    African Journals Online (AJOL)

    L'objectif de ce travail est l'évaluation agronomique de la qualité du sol sous vigne et sous blé dans la région Mohammedia-Benslimane au Maroc, à travers les indicateurs chimiques de la qualité du sol (pH, CE, CaCO3, Carbone organique total, Azote, Phosphore et Potassium). Les résultats de cette étude montrent que ...

  13. Biaxial seismic behaviour of reinforced concrete columns =

    Science.gov (United States)

    Rodrigues, Hugo Filipe Pinheiro

    A analise dos efeitos dos sismos mostra que a investigacao em engenharia sismica deve dar especial atencao a avaliacao da vulnerabilidade das construcoes existentes, frequentemente desprovidas de adequada resistencia sismica tal como acontece em edificios de betao armado (BA) de muitas cidades em paises do sul da Europa, entre os quais Portugal. Sendo os pilares elementos estruturais fundamentais na resistencia sismica dos edificios, deve ser dada especial atencao a sua resposta sob acoes ciclicas. Acresce que o sismo e um tipo de acao cujos efeitos nos edificios exige a consideracao de duas componentes horizontais, o que tem exigencias mais severas nos pilares comparativamente a acao unidirecional. Assim, esta tese centra-se na avaliacao da resposta estrutural de pilares de betao armado sujeitos a acoes ciclicas horizontais biaxiais, em tres linhas principais. Em primeiro lugar desenvolveu-se uma campanha de ensaios para o estudo do comportamento ciclico uniaxial e biaxial de pilares de betao armado com esforco axial constante. Para tal foram construidas quatro series de pilares retangulares de betao armado (24 no total) com diferentes caracteristicas geometricas e quantidades de armadura longitudinal, tendo os pilares sido ensaiados para diferentes historias de carga. Os resultados experimentais obtidos sao analisados e discutidos dando particular atencao a evolucao do dano, a degradacao de rigidez e resistencia com o aumento das exigencias de deformacao, a energia dissipada, ao amortecimento viscoso equivalente; por fim e proposto um indice de dano para pilares solicitados biaxialmente. De seguida foram aplicadas diferentes estrategias de modelacao nao-linear para a representacao do comportamento biaxial dos pilares ensaiados, considerando nao-linearidade distribuida ao longo dos elementos ou concentrada nas extremidades dos mesmos. Os resultados obtidos com as varias estrategias de modelacao demonstraram representar adequadamente a resposta em termos das curvas

  14. Biaxial failure criteria and stress-strain response for concrete of containment structure

    International Nuclear Information System (INIS)

    Lee, S. K.; Woo, S. K.; Song, Y. C.; Kweon, Y. K.; Cho, C. H.

    2001-01-01

    Biaxial failure criteria and stress-strain response for plain concrete of containment structure on nuclear power plants are studied under uniaxial and biaxial stress(compression-compression, compression-tension, and tension-tension combined stress). The concrete specimens of a square plate type are used for uniaxial and biaxial loading. The experimental data indicate that the strength of concrete under biaxial compression, f 2 /f 1 =-1/-1, is 17 percent larger than under uniaxial compression and the poisson's ratio of concrete is 0.1745. On the base of the results, a biaxial failure envelope for plain concrete that the uniaxial strength is 5660 psi are provided, and the biaxial failure behaviors for three biaxial loading areas are plotted respectively. And, various analytical equations having the reliability are proposed for representations of the biaxial failure criteria and stress-strain response curves of concrete

  15. Depletion-induced biaxial nematic states of boardlike particles

    International Nuclear Information System (INIS)

    Belli, S; Van Roij, R; Dijkstra, M

    2012-01-01

    With the aim of investigating the stability conditions of biaxial nematic liquid crystals, we study the effect of adding a non-adsorbing ideal depletant on the phase behavior of colloidal hard boardlike particles. We take into account the presence of the depletant by introducing an effective depletion attraction between a pair of boardlike particles. At fixed depletant fugacity, the stable liquid-crystal phase is determined through a mean-field theory with restricted orientations. Interestingly, we predict that for slightly elongated boardlike particles a critical depletant density exists, where the system undergoes a direct transition from an isotropic liquid to a biaxial nematic phase. As a consequence, by tuning the depletant density, an easy experimental control parameter, one can stabilize states of high biaxial nematic order even when these states are unstable for pure systems of boardlike particles. (paper)

  16. Failure of composite plates under static biaxial planar loading

    Science.gov (United States)

    Waas, Anthony M.; Khamseh, Amir R.

    1992-01-01

    The project involved detailed investigations into the failure mechanisms in composite plates as a function of hole size (holes centrally located in the plates) under static loading. There were two phases to the project, the first dealing with uniaxial loads along the fiber direction, and the second dealing with coplanar biaxial loading. Results for the uniaxial tests have been reported and published previously, thus this report will place emphasis on the second phase of the project, namely the biaxial tests. The composite plates used in the biaxial loading experiments, as well as the uniaxial, were composed of a single ply unidirectional graphite/epoxy prepreg sandwiched between two layers of transparent thermoplastic. This setup enabled us to examine the failure initiation and propagation modes nondestructively, during the test. Currently, similar tests and analysis of results are in progress for graphite/epoxy cruciform shaped flat laminates. The results obtained from these tests will be available at a later time.

  17. Biaxial deformation behaviour of poly-ether-ether-ketone

    Science.gov (United States)

    Turner, Josh; Menary, Gary; Martin, Peter

    2018-05-01

    The biaxial tensile properties of thin poly-ether-ether-ketone (PEEK) films are presented. Investigation into the biaxial mechanical behaviour of PEEK films will provide a preliminary insight into the anticipated stress/strain response, and potential suitability, to the possible fabrication of thin walled parts through stretch blow moulding and thermoforming processes - with the multi-axial state of strain imposed onto the heated thermoplastic sheet representative of the expected strain history experienced during these material forming processes. Following identification of the prospective forming temperature window, the biaxial mechanical behaviour of the material is characterized under differing modes of deformation, at a nominal strain rate of 1 s-1. The temperature dependence is outlined within - with an appreciable increase in flow behaviour correlated with specimen temperature exceeding its glass transition temperature (Tg).

  18. Method for forming biaxially textured articles by powder metallurgy

    Science.gov (United States)

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2002-01-01

    A method of preparing a biaxially textured alloy article comprises the steps of preparing a mixture comprising Ni powder and at least one powder selected from the group consisting of Cr, W, V, Mo, Cu, Al, Ce, YSZ, Y, Rare Earths, (RE), MgO, CeO.sub.2, and Y.sub.2 O.sub.3 ; compacting the mixture, followed by heat treating and rapidly recrystallizing to produce a biaxial texture on the article. In some embodiments the alloy article further comprises electromagnetic or electro-optical devices and possesses superconducting properties.

  19. Characterization Of Biaxial Strain Of Poly(L-Lactide) Tubes

    DEFF Research Database (Denmark)

    Løvdal, Alexandra Liv Vest; Andreasen, Jens Wenzel; Mikkelsen, Lars Pilgaard

    2016-01-01

    Poly(L-lactide) (PLLA) in its L-form has promising mechanical properties. Being a semi-crystalline polymer, it can be subjected to strain-induced crystallization at temperatures above Tg and can thereby become oriented. Following a simultaneous (SIM) biaxial strain process or a sequential (SEQ...

  20. Anomalously temperature-independent birefringence in biaxial optical crystals

    International Nuclear Information System (INIS)

    Grechin, Sergei G; Dmitriev, Valentin G; Dyakov, Vladimir A; Pryalkin, Vladimir I

    2000-01-01

    Temperature-independent birefringence in a biaxial crystal was predicted theoretically and observed experimentally for the first time. The width of the plot against temperature (the range corresponding to the temperature independence of the birefringence) at a fundamental radiation wavelength of 632.8 nm in a KTP crystal 5.9 mm long was more than 160 0 C. (letters to the editor)

  1. Biaxial charts for rectangular reinforced columns in accordance with ...

    African Journals Online (AJOL)

    linearity arising from the non-linear stress-strain relationships and the cracking of the cross-section. · As a result, the systematic production of biaxial design charts necessitates the application of numerical methods that are based on iterations.

  2. Methodology for dynamic biaxial tension testing of pregnant uterine tissue.

    Science.gov (United States)

    Manoogian, Sarah; Mcnally, Craig; Calloway, Britt; Duma, Stefan

    2007-01-01

    Placental abruption accounts for 50% to 70% of fetal losses in motor vehicle crashes. Since automobile crashes are the leading cause of traumatic fetal injury mortality in the United States, research of this injury mechanism is important. Before research can adequately evaluate current and future restraint designs, a detailed model of the pregnant uterine tissues is necessary. The purpose of this study is to develop a methodology for testing the pregnant uterus in biaxial tension at a rate normally seen in a motor vehicle crash. Since the majority of previous biaxial work has established methods for quasi-static testing, this paper combines previous research and new methods to develop a custom designed system to strain the tissue at a dynamic rate. Load cells and optical markers are used for calculating stress strain curves of the perpendicular loading axes. Results for this methodology show images of a tissue specimen loaded and a finite verification of the optical strain measurement. The biaxial test system dynamically pulls the tissue to failure with synchronous motion of four tissue grips that are rigidly coupled to the tissue specimen. The test device models in situ loading conditions of the pregnant uterus and overcomes previous limitations of biaxial testing. A non-contact method of measuring strains combined with data reduction to resolve the stresses in two directions provides the information necessary to develop a three dimensional constitutive model of the material. Moreover, future research can apply this method to other soft tissues with similar in situ loading conditions.

  3. Biaxial potential of surface-stabilized ferroelectric liquid crystals

    Science.gov (United States)

    Kaznacheev, Anatoly; Pozhidaev, Evgeny; Rudyak, Vladimir; Emelyanenko, Alexander V.; Khokhlov, Alexei

    2018-04-01

    A biaxial surface potential Φs of smectic-C* surface-stabilized ferroelectric liquid crystals (SSFLCs) is introduced in this paper to explain the experimentally observed electric-field dependence of polarization P˜cell(E ) , in particular the shape of the static hysteresis loops. Our potential consists of three independent parts. The first nonpolar part Φn describes the deviation of the prime director n (which is the most probable orientation of the long molecular axes) from the easy alignment axis R , which is located in the boundary surface plane. It is introduced in the same manner as the uniaxial Rapini potential. The second part Φp of the potential is a polar term associated with the presence of the polar axis in a FLC. The third part Φm relates to the inherent FLC biaxiality, which has not been taken into consideration previously. The Φm part takes into account the deviations of the secondary director m (which is the most probable orientation of the short molecular axes) from the normal to the boundary surface. The overall surface potential Φs, which is a sum of Φn,Φp , and Φm, allows one to model the conditions when either one, two, or three minima of the SSFLC cell free energy are realized depending on the biaxiality extent. A monodomain or polydomain structure, as well as the bistability or monostability of SSFLC cells, depends on the number of free-energy minima, as confirmed experimentally. In this paper, we analyze the biaxiality impact on the FLC alignment. We also answer the question of whether the bistable or monostable structure can be formed in an SSFLC cell. Our approach is essentially based on a consideration of the biaxial surface potential, while the uniaxial surface potential cannot adequately describe the experimental observations in the FLC.

  4. Deep geothermal energy: the Soultz-sous-Forets experience

    International Nuclear Information System (INIS)

    Genter, A.; Guenot, N.; Graff, J.J.

    2010-01-01

    This paper presents the mining exploitation project of the geothermal heat at Soultz-sous-Forets, located 50 km NE of Strasbourg (Bas Rhin, France). A geothermal power plant, inaugurated mid-2008, will commercialize its own power generation soon. This power plant is owned by a consortium of French-German industrialists through the European economical interest group for the mining exploitation of heat. The paper presents the geological characteristics of the hot dry rock geothermal reservoir, the deep geothermal wells, the hydraulic stimulation of the reservoir rock, the surface equipments of the power plants and the production pumps, the activities of the site in 2008 and 2009 and the perspectives of development of this energy source in France in the light of the Soultz-sous-Forets site experience. (J.S.)

  5. Strain Measurement System Developed for Biaxially Loaded Cruciform Specimens

    Science.gov (United States)

    Krause, David L.

    2000-01-01

    A new extensometer system developed at the NASA Glenn Research Center at Lewis Field measures test area strains along two orthogonal axes in flat cruciform specimens. This system incorporates standard axial contact extensometers to provide a cost-effective high-precision instrument. The device was validated for use by extensive testing of a stainless steel specimen, with specimen temperatures ranging from room temperature to 1100 F. In-plane loading conditions included several static biaxial load ratios, plus cyclic loadings of various waveform shapes, frequencies, magnitudes, and durations. The extensometer system measurements were compared with strain gauge data at room temperature and with calculated strain values for elevated-temperature measurements. All testing was performed in house in Glenn's Benchmark Test Facility in-plane biaxial load frame.

  6. Limit load assessment of centre cracked plates under biaxial loading

    International Nuclear Information System (INIS)

    Meek, C.; Ainsworth, R.A.

    2015-01-01

    Fitness-for-service of equipment and components containing defects is generally assessed using procedures such as BS 7910, API 579 and R6. There is currently little detailed advice in these procedures on the effects of biaxial and triaxial loading on fracture. This poster shows some theoretical bounding solutions of the plastic limit load for centre cracked plates under a variety of biaxial loading ratios and compares the estimates with those found by numerical methods using finite element (FE) analysis using Abacus CAE modelling software. The limit load of a structure is the maximum load that it can carry before plastic collapse occurs; this is often when the plastic zone has become large enough to spread from the crack tip to a remote boundary. For an elastic-perfectly plastic material, the irreversible deformation will continue at stresses no higher than the yield stress. The model for these limit load solutions is a bi-axially loaded plate of width 2W and height 2H, a centre crack of width 2a, acted on by remotely applied uniform stresses σ 2 perpendicular to the crack and Bσ 2 parallel to the crack, where B is the biaxial loading ratio, it means the ratio of the parallel to the perpendicular stress. A quarter plate of an elastic-perfectly plastic material has been modelled. The results show that an exact solution has been found for negative and low positive values of B. For B > 1, the lower bound solution is conservative for all values of a/W and B

  7. Efficient Driving of Piezoelectric Transducers Using a Biaxial Driving Technique.

    Directory of Open Access Journals (Sweden)

    Samuel Pichardo

    Full Text Available Efficient driving of piezoelectric materials is desirable when operating transducers for biomedical applications such as high intensity focused ultrasound (HIFU or ultrasound imaging. More efficient operation reduces the electric power required to produce the desired bioeffect or contrast. Our preliminary work [Cole et al. Journal of Physics: Condensed Matter. 2014;26(13:135901.] suggested that driving transducers by applying orthogonal electric fields can significantly reduce the coercivity that opposes ferroelectric switching. We present here the experimental validation of this biaxial driving technique using piezoelectric ceramics typically used in HIFU. A set of narrow-band transducers was fabricated with two sets of electrodes placed in an orthogonal configuration (following the propagation and the lateral mode. The geometry of the ceramic was chosen to have a resonance frequency similar for the propagation and the lateral mode. The average (± s.d. resonance frequency of the samples was 465.1 (± 1.5 kHz. Experiments were conducted in which each pair of electrodes was driven independently and measurements of effective acoustic power were obtained using the radiation force method. The efficiency (acoustic/electric power of the biaxial driving method was compared to the results obtained when driving the ceramic using electrodes placed only in the pole direction. Our results indicate that the biaxial method increases efficiency from 50% to 125% relative to the using a single electric field.

  8. Analysis and experimental validation of through-thickness cracked large-scale biaxial fracture tests

    International Nuclear Information System (INIS)

    Wiesner, C.S.; Goldthorpe, M.R.; Andrews, R.M.; Garwood, S.J.

    1999-01-01

    Since 1984 TWI has been involved in an extensive series of tests investigating the effects of biaxial loading on the fracture behaviour of A533B steel. Testing conditions have ranged from the lower to upper shelf regions of the transition curve and covered a range of biaxiality ratios. In an attempt to elucidate the trends underlying the experimental results, finite element-based mechanistic models were used to analyse the effects of biaxial loading. For ductile fracture, a modified Gunson model was used and important effects on tearing behaviour were found for through thickness cracked wide plates, as observed in upper shelf tests. For cleavage fracture, both simple T-stress methods and the Anderson-Dodds and Beremin models were used. Whilst the effect of biaxiality on surface cracked plates was small, a marked effect of biaxial loading was found for the through-thickness crack. To further validate the numerical predictions for cleavage fracture, TWI have performed an additional series of lower shelf through thickness cracked biaxial wide plate fracture tests. These tests were performed using various biaxiality loading conditions varying from simple uniaxial loading, through equibiaxial loading, to a biaxiality ratio equivalent to a circumferential crack in a pressure vessel. These tests confirmed the predictions that there is a significant effect of biaxial loading on cleavage fracture of through thickness cracked plate. (orig.)

  9. Application of magnetomechanical hysteresis modeling of magnetic techniques for monitoring neutron embrittlement and biaxial stress

    International Nuclear Information System (INIS)

    Sablik, M.J.; Kwun, H.; Burkhardt, G.L.

    1993-01-01

    Research was done on the biaxial stress problem accomplished in the first half of the second year. All of the work done was preparatory to magnetic measurements. Issues addressed were: construction of a model for extracting changes in the magnetic properties of a specimen from the readings of an indirect sensor; initial development of a model for how biaxial stress alters the intrinsic magnetic properties of thespecimen; use of finite element stress analysis modeling to determine a detailed shape for the cruciform biaxial stress specimen; and construction of the biaxial stress loading apparatus

  10. Comportement des fondations et des ancrages de structures marines sous l'effet de sollicitations cycliques Behavior of Foundations and Anchors for Marine Structures under the Effect of Cyclic Stresses

    Directory of Open Access Journals (Sweden)

    Le Tirant P.

    2006-11-01

    Full Text Available L'exploration et l'exploitation des hydrocarbures en haute mer conduisent à la mise en place d'ouvrages fixes ou flottants de dimensions de plus en plus colos sales, par des profondeurs d'eau sans cesse croissantes, atteignant actuellement 200 à 300 mètres en production, un millier de mètres en exploration. Les fondations des ouvrages pétroliers de production comprennent essentiel-lement- les pieux ou groupes de pieux, battus ou forés; - les fondations superficielles à embase poids. Le comportement des fondations ou ancrages de structures sous l'action des sollicitations cycliques est étudié, en fonction de la nature des terrains, à partir - de mesures et d'observations sur des structures réelles; d'expérimentations sur des modèles en semi-grandeur ou de simulations sur modèles réduits. Les exemples donnés situent la diversité des problèmes rencontrés pour l'instal-lation des ouvrages en haute mer et! l'ampleur des travaux nécessaires pour décrire plus correctement les phénomènes d'intéraction sols-structures mannes sous l'effet des chargements cycliques et transitoires et, par suite, mieux optimiser le dimensionnement des fondations et des ancrages. Exploration and production of hydrocarbons in the high seas lead ta the installation of fixed or floating structures having more and more colossal sizes at constantly increasing water depths which now attain 200 ta 300 meters for production and 1000 meters for exploration. The foundations of ail production structures mainly consist of - pilings or groups of pilings, either driven or drilled; superficial gravity foundations the behovior of foundations or anchors for such structures under the effect of cyclic stresses is examined as a function of the nature of formations, on the basis of - measurements and observations on actual structures, experiments with semi-full-sized models or by simulations with scale models. The examples given illustrate the diversity of the problems

  11. Plate forme L3 informatique sous application android

    OpenAIRE

    BENDEDDOUCHE, Rida; BENAMARA, Mohammed El Amin

    2014-01-01

    Ce travail est présenté dans le cadre de notre projet de fin d’étude licence en informatique. Nous sommes actuellement dans une étape de transition de l’informatique fixe à l’informatique mobile. De jour en jour l’optimisation des smartphones ne cesse d’augmenter et cela grâce aux applications mobiles. Les smartphones utilisent plusieurs systèmes d’exploitation, une grande partie est sous Android. Les Smartphones et tablettes ont été conçus pour faciliter la vie quotidienne. En partant de ce ...

  12. Lightweight, Low-CTE Tubes Made From Biaxially Oriented LCPs

    Science.gov (United States)

    Rubin, Leslie; Federico, Frank; Formato, Richard; Larouco, John; Slager, William

    2004-01-01

    Tubes made from biaxially oriented liquid-crystal polymers (LCPs) have been developed for use as penetrations on cryogenic tanks. ( Penetrations in this context denotes feed lines, vent lines, and sensor tubes, all of which contribute to the undesired conduction of heat into the tanks.) In comparison with corresponding prior cryogenic-tank penetrations made from stainless steels and nickel alloys, the LCP penetrations offer advantages of less weight and less thermal conduction. An additional major advantage of LCP components is that one can tailor their coefficients of thermal expansion (CTEs). The estimated cost of continuous production of LCP tubes of typical sizes is about $1.27/ft ($4.17/m) [based on 1998 prices]. LCP tubes that are compatible with liquid oxygen and that feature tailored biaxial molecular orientation and quasi-isotropic properties (including quasi-isotropic CTE) have been fabricated by a combination of proprietary and patented techniques that involve the use of counterrotating dies (CRDs). Tailoring of the angle of molecular orientation is what makes it possible to tailor the CTE over a wide range to match the CTEs of adjacent penetrations of other tank components; this, in turn, makes it possible to minimize differential-thermal expansion stresses that arise during thermal cycling. The fabrication of biaxially oriented LCP tubes by use of CRDs is not new in itself. The novelty of the present development lies in tailoring the orientations and thus the CTEs and other mechanical properties of the LCPs for the intended cryogenic applications and in modifications of the CRDs for this purpose. The LCP tubes and the 304-stainless-steel tubes that the LCP tubes were intended to supplant were tested with respect to burst strength, permeability, thermal conductivity, and CTE.

  13. Field-Induced Rheology in Uniaxial and Biaxial Fields

    International Nuclear Information System (INIS)

    MARTIN, JAMES E.

    1999-01-01

    Steady and oscillatory shear 3-D simulations of electro- and magnetorheology in uniaxial and biaxial fields are presented, and compared to the predictions of the chain model. These large scale simulations are three dimensional, and include the effect of Brownian motion. In the absence of thermal fluctuations, the expected shear thinning viscosity is observed in steady shear, and a striped phase is seen to rapidly form in a uniaxial field, with a shear slip zone in each sheet. However, as the influence of Brownian motion increases, the fluid stress decreases, especially at lower Mason numbers, and the striped phase eventually disappears, even when the fluid stress is still high. In a biaxial field, an opposite trend is seen, where Brownian motion decreases the stress most significantly at higher Mason numbers. to account for the uniaxial steady shear data they propose a microscopic chain model of the role played by thermal fluctuations on the rheology of ER and MR fluids that delineates the regimes where an applied field can impact the fluid viscosity, and gives an analytical prediction for the thermal effect. In oscillatory shear, a striped phase again appears in uniaxial field, at strain amplitudes greater than(approx) 0.15, and the presence of a shear slip zone creates strong stress nonlinearities at low strain amplitudes. In a biaxial field, a shear slip zone is not created, and so the stress nonlinearities develop only at expected strain amplitudes. The nonlinear dynamics of these systems is shown to be in good agreement with the Kinetic Chain Model

  14. Hole doped Dirac states in silicene by biaxial tensile strain

    KAUST Repository

    Kaloni, Thaneshwor P.; Cheng, Yingchun; Schwingenschlö gl, Udo

    2013-01-01

    The effects of biaxial tensile strain on the structure, electronic states, and mechanical properties of silicene are studied by ab-initio calculations. Our results show that up to 5% strain the Dirac cone remains essentially at the Fermi level, while higher strain induces hole doped Dirac states because of weakened Si–Si bonds. We demonstrate that the silicene lattice is stable up to 17% strain. It is noted that the buckling first decreases with the strain (up to 10%) and then increases again, which is accompanied by a band gap variation. We also calculate the Grüneisen parameter and demonstrate a strain dependence similar to that of graphene.

  15. Hole doped Dirac states in silicene by biaxial tensile strain

    KAUST Repository

    Kaloni, Thaneshwor P.

    2013-03-11

    The effects of biaxial tensile strain on the structure, electronic states, and mechanical properties of silicene are studied by ab-initio calculations. Our results show that up to 5% strain the Dirac cone remains essentially at the Fermi level, while higher strain induces hole doped Dirac states because of weakened Si–Si bonds. We demonstrate that the silicene lattice is stable up to 17% strain. It is noted that the buckling first decreases with the strain (up to 10%) and then increases again, which is accompanied by a band gap variation. We also calculate the Grüneisen parameter and demonstrate a strain dependence similar to that of graphene.

  16. Light propagation in a magneto-optical hyperbolic biaxial crystal

    Science.gov (United States)

    Kuznetsov, Evgeniy V.; Merzlikin, Alexander M.

    2017-12-01

    The light propagation through a magneto-optical hyperbolic biaxial crystal is investigated. Magnetization of the structure results in splitting and reconnection of an isofrequency near the self-intersection point and thus it leads to the disappearance of conical refraction in a crystal. In its turn the isofrequency splitting leads to band gap opening and makes it possible to steer the beam. These effects allow to control the light propagation by means of an external magnetostatic field. The Poynting's vector distribution in the crystal is calculated by means of a Fourier transform in order to demonstrate the aforementioned effects.

  17. Effects of various surface treatments on the biaxial flexural properties of yttria-stabilized zirconia ceramics

    Directory of Open Access Journals (Sweden)

    Teerthesh Jain

    2018-01-01

    Conclusions: Air particle abrasion with CoJet Sand, LTD, and CTs had no negative impact on biaxial flexural strength indeed it increased the biaxial flexural strength. Hence, these surface treatments can be done in routine clinical practice to improve the performance of ceramic restorations.

  18. Sol-gel deposition of buffer layers on biaxially textured metal substances

    Science.gov (United States)

    Shoup, Shara S.; Paranthamam, Mariappan; Beach, David B.; Kroeger, Donald M.; Goyal, Amit

    2000-01-01

    A method is disclosed for forming a biaxially textured buffer layer on a biaxially oriented metal substrate by using a sol-gel coating technique followed by pyrolyzing/annealing in a reducing atmosphere. This method is advantageous for providing substrates for depositing electronically active materials thereon.

  19. Le harcèlement organisationnel des relations sous emprise

    CERN Document Server

    Guhel, Cécile

    2014-01-01

    Le lien entre harcèlement et emprise professionnelle est bien réel. Il est aussi puissant que destructeur. L'aide extérieure est importante mais la prise de conscience du sujet et sa mise à distance sont primordiales pour le retour à Soi. Un facteur de risque organisationnel est un facteur qui relève de l'organisation et qui comporte le risque ou la probabilité qu'un tel comportement abusif voie le jour et qu'il ait des effets négatifs. Un tel facteur peut également contribuer à la persistance ou à l'aggravation du comportement. En abordant la relation d'emprise sous l'éclairage de différentes théories psychologiques, cela vous permettra d'observer les mécanismes intrapsychiques conscients et inconscients qui sous-tendent les comportements de l'instigateur de la relation d'emprise d'une part, et de sa victime d'autre part. Enfin, à travers trois témoignages, de salariées en poste, vous découvrirez combien la parole sur le travail est importante dans la prise de conscience du processus de de...

  20. Acoustic emission under biaxial stresses in unflawed 21-6-9 and 304 stainless steel

    International Nuclear Information System (INIS)

    Hamstad, M.A.; Leon, E.M.; Mukherjee, A.K.

    1980-01-01

    Acoustic emission (AE) testing has been carried out with uniaxial and biaxial (2:1 stress ratio) stressing of smooth samples of 21-6-9 and 304 stainless steel (SS). Uniaxial testing was done with simple tensile and compression samples as well as with the special biaxial specimens. Biaxial tensile stressing was accomplished with a specially designed specimen, which had been used previously to characterize AE in 7075 aluminum under biaxial stressing. Results were obtained for air-melt and for vacuum-melt samples of 21-6-9 SS. The air-melt samples contain considerably more inclusion particles than the vacuum-melt samples. For the 304 SS, as received material was examined. To allow AE correlations with microstructure, extensive characterization of the 21-6-9 microstructure was carried out. Significant differences in AE occur in biaxially stressed specimens as compared to uniaxially stressed samples. 15 figures, 3 tables

  1. Modeling of delayed strains of concrete under biaxial loadings. Application to the reactor containment of nuclear power plants; Modelisation des deformations differees du beton sous sollicitations biaxiales. application aux enceintes de confinement de batiments reacteurs des centrales nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Benboudjema, F

    2002-12-15

    The prediction of delayed strains is of crucial importance for durability and long-term serviceability of concrete structures (bridges, containment vessels of nuclear power plants, etc.). Indeed, creep and shrinkage cause cracking, losses of pre-stress and redistribution of stresses, and also, rarely, the ruin of the structure. The objective of this work is to develop numerical tools, able to predict the long-term behavior of concrete structures. Thus, a new hydro mechanical model is developed, including the description of drying, shrinkage, creep and cracking phenomena for concrete as a non-saturated porous medium. The modeling of drying shrinkage is based on an unified approach of creep and shrinkage. Basic and drying creep models are based on relevant chemo-physical mechanisms, which occur at different scales of the cement paste. The basic creep is explicitly related to the micro-diffusion of the adsorbed water between inter-hydrates and intra-hydrates and the capillary pores, and the sliding of the C-S-H gel at the nano-porosity level. The drying creep is induced by the micro-diffusion of the adsorbed water at different scales of the porosity, under the simultaneous effects of drying and mechanical loadings. Drying shrinkage is, therefore, assumed to result from the elastic and delayed response of the solid skeleton, submitted to both capillary and disjoining pressures. Furthermore, the cracking behavior of concrete is described by an orthotropic elastoplastic damage model. The coupling between all these phenomena is performed by using effective stresses which account for both external applied stresses and pore pressures. This model has been incorporated into a finite element code. The analysis of the long-term behavior is also performed on concrete specimens and prestressed concrete structures submitted to simultaneous drying and mechanical loadings. (author)

  2. Biaxial fatigue crack propagation behavior of perfluorosulfonic-acid membranes

    Science.gov (United States)

    Lin, Qiang; Shi, Shouwen; Wang, Lei; Chen, Xu; Chen, Gang

    2018-04-01

    Perfluorosulfonic-acid membranes have long been used as the typical electrolyte for polymer-electrolyte fuel cells, which not only transport proton and water but also serve as barriers to prevent reactants mixing. However, too often the structural integrity of perfluorosulfonic-acid membranes is impaired by membrane thinning or cracks/pinholes formation induced by mechanical and chemical degradations. Despite the increasing number of studies that report crack formation, such as crack size and shape, the underlying mechanism and driving forces have not been well explored. In this paper, the fatigue crack propagation behaviors of Nafion membranes subjected to biaxial loading conditions have been investigated. In particular, the fatigue crack growth rates of flat cracks in responses to different loading conditions are compared, and the impact of transverse stress on fatigue crack growth rate is clarified. In addition, the crack paths for slant cracks under both uniaxial and biaxial loading conditions are discussed, which are similar in geometry to those found after accelerated stress testing of fuel cells. The directions of initial crack propagation are calculated theoretically and compared with experimental observations, which are in good agreement. The findings reported here lays the foundation for understanding of mechanical failure of membranes.

  3. Biaxial experimental and analytical characterization of a dielectric elastomer

    Science.gov (United States)

    Helal, Alexander; Doumit, Marc; Shaheen, Robert

    2018-01-01

    Electroactive polymers (EAPs) have emerged as a strong contender for use in low-cost efficient actuators in multiple applications especially related to biomimetic and mobile-assistive devices. Dielectric elastomers (DE), a subcategory of these smart materials, have been of particular interest due to their large achievable deformation and favourable mechanical and electro-mechanical properties. Previous work has been completed to understand the behaviour of these materials; however, their properties require further investigation to properly integrate them into real-world applications. In this study, a biaxial tensile experimental evaluation of 3M™ VHB 4905 and VHB 4910 is presented with the purpose of illustrating the elastomers' transversely isotropic mechanical behaviours. These tests were applied to both tapes for equibiaxial stretch rates ranging between 0.025 and 0.300 s-1. Subsequently, a dynamic planar biaxial visco-hyperelastic constitutive relationship was derived from a Kelvin-Voigt rheological model and the general Hooke's law for transversely isotropic materials. The model was then fitted to the experimental data to obtain three general material parameters for either tapes. The model's ability to predict tensile stress response and internal energy dissipation, with respect to experimental data, is evaluated with good agreement. The model's ability to predict variations in mechanical behaviour due to changes in kinematic variables is then illustrated for different conditions.

  4. Biaxial loading effects on the growth of cracks

    International Nuclear Information System (INIS)

    Brown, M.W.; Miller, K.J.; Walker, T.J.

    1983-01-01

    Fatigue crack growth under different biaxial stress states is considered for both small scale yielding and high bulk stress conditions. Analytical and elastic finite element results are compared favourably alongside experimental results on a AISI 316 stainless steel at both room and elevated temperatures. Differences in crack growth rates are compared against different crack tip cyclic plastic zone sizes for various degrees of mixed mode loading, thereby overcoming the limitations of the Paris Law and LEFM. The usefulness of the approach is indicated for studies in the behaviour of materials subjected to thermal shock. Where steep temperature gradients are introduced due to rapid thermal transients, high strains are produced which propagate fatigue cracks under cyclic conditions. Since stress gradients are generally associated with thermal shock situations, the cracks grow through a plastically deformed region near the surface into an elastic region. A unified approach to fatigue behaviour, encompassing both linear elastic and elastic-plastic fracture mechanics, will enable analysis of thermal shock situations. The approach to crack propagation developed here shows that cyclic growth rates are a function of a severe strain zone size in which local stresses exceed the tensile strength, i.e. monotonic instability. The effects of stress biaxiality and mixed mode loading are included in the analysis, which may be extended to general yielding situations. (orig.)

  5. Changes in Meat Quality Characteristics of the Sous-vide Cooked Chicken Breast during Refrigerated Storage.

    Science.gov (United States)

    Hong, Go-Eun; Kim, Ji-Han; Ahn, Su-Jin; Lee, Chi-Ho

    2015-01-01

    This study was performed to investigate the changes in meat quality characteristics of the sous vide cooked chicken breast during refrigerated storage at 4℃ for 14 d between before and after sous-vide cooking. Cooking loss and shear force were significantly increased, whereas expressible drip was significantly decreased along with reduction in the water holding capacity in both of two groups. Redness of meat juice was significantly (p<0.05) increased during storage, and considerably increased in the refrigerated samples after sous-vide cooked at the 7 to 10 d. The thiobarbituric acid reactive substances (TBARS) was significantly increased and was higher in the refrigerator stored chicken breast samples after sous-vide cooking. The volatile basic nitrogen (VBN) value was significantly increased in both groups, but the VBN value of the stored raw meat sample before sous-vide cooking was increased at an early storage, while the VBN value of the stored sample after sous-vide cooking was increased gradually in this study. Total viable counts and coliform counts were significantly decreased during storage, and coliforms were not detected after 7 d of storage in both groups. Salmonella spp. was not detected during the whole studied period. The outcome of this research can provide preliminary data that could be used to apply for further study of chicken breast using sous-vide cooking method that could be attractive to consumers.

  6. Pollution urbaine : la France sous le dôme

    OpenAIRE

    Laurent, Eloi

    2017-01-01

    Un an exactement après avoir accueilli la COP21, Paris suffoquait début décembre sous un dôme de pollution, mais aussi Lyon, Villeurbanne, Marseille, Avignon, Rouen ou Grenoble. Airparif, qui a relevé un niveau de particules fines de 146 µg/m3 à Paris en moyenne pour le 1er décembre, précisait dans un communiqué qu’il s’agissait là d’un des pics hivernaux de pollution les plus sévères de ces dix dernières années, les précédents remontant à janvier 2009 et décembre 2007.

  7. Numerical analysis oriented biaxial stress-strain relation and failure criterion of plain concrete

    International Nuclear Information System (INIS)

    Link, J.

    1975-01-01

    A biaxial stress-strain relation and failure criterion is proposed, which is applicable to structural analysis methods. The formulation of material behavior of plain concrete in biaxial stress-state was developed. A nonlinear elastic, anisotropic stress-strain relation was derived with two moduli of elasticity, E 1 , E 2 and Poisson's ratios, ν 1 , ν 2 , which depend on the prevailing biaxial stress state. The stress-strain relation is valid in the whole biaxial stress field, that means with a smooth transition between the domains of tension/tension, tension/compression and compression/compression. The stress-dependent moduli E 1 , E 2 and the Poisson's ratios ν 1 , ν 2 are approximated by polynomials, trigonometrical and exponential functions. A failure criterion was defined by approximating the test results of the biaxial ultimate concrete strength with a 7th degree polynomial, which is also valid in the whole biaxial stress domain. The definition of the state of failure is given as a function of stresses as well as strains. Initial parameters of the formulation of the biaxial material behavior are the uniaxial cylindrical strength of concrete and the initial values of Young's modulus and Poisson's ratio. A simple expansion of this formulation makes it applicable not only to normal but also to light-weight concrete. Comparison of numerically calculated stress-strain curves up to the ultimate biaxial stresses which indicate the failure criteria with those obtained from tests show a very good agreement. It is shown, that the biaxial stress-strain relation can be extended for use in cases of triaxial tension/tension/compression stress state. Numerical examples of analysis of concrete slabs show the importance of incorporation of a realistic material behavior for better safety estimations

  8. Intradomain Textures in Block Copolymers: Multizone Alignment and Biaxiality

    Science.gov (United States)

    Prasad, Ishan; Seo, Youngmi; Hall, Lisa M.; Grason, Gregory M.

    2017-06-01

    Block copolymer (BCP) melt assembly has been studied for decades, focusing largely on self-organized spatial patterns of periodically ordered segment density. Here, we demonstrate that underlying the well-known composition profiles (i.e., ordered lamella, cylinders, spheres, and networks) are generic and heterogeneous patterns of segment orientation that couple strongly to morphology, even in the absence of specific factors that promote intra or interchain segment alignment. We employ both self-consistent field theory and coarse-grained simulation methods to measure polar and nematic order parameters of segments in a freely jointed chain model of diblock melts. We show that BCP morphologies have a multizone texture, with segments predominantly aligned normal and parallel to interdomain interfaces in the respective brush and interfacial regions of the microdomain. Further, morphologies with anisotropically curved interfaces (i.e., cylinders and networks) exhibit biaxial order that is aligned to the principal curvature axes of the interface.

  9. Creep modeling of textured zircaloy under biaxial stressing

    International Nuclear Information System (INIS)

    Adams, B.L.; Murty, K.L.

    1984-01-01

    Anisotropic biaxial creep behavior of textured Zircaloy tubing was modeled using a crystal-plastic uniform strain-rate upper-bound and a uniform stress lower-bound approach. Power-law steady-state creep is considered to occur on each crystallite glide system by fixing the slip rate to be proportional to the resolved shear stress raised to a power. Prismatic, basal, and pyramidal slip modes were considered. The crystallographic texture is characterized using the orientation distribution function determined from a set of three pole-figures. This method is contrasted with a Von-Mises-Hill phenomenological model in comparison with experimental data obtained at 673 deg K. The resulting creep-dissipative loci show the importance of the basal slip mode on creep in heavily cold-worked cladding, whereas prismatic slip is more important for the recrystallized materials. (author)

  10. Anisotropic yield surfaces in bi-axial cyclic plasticity

    International Nuclear Information System (INIS)

    Rider, R.J.; Harvey, S.J.; Breckell, T.H.

    1985-01-01

    Some aspects of the behaviour of yield surfaces and work-hardening surfaces occurring in biaxial cyclic plasticity have been studied experimentally and theoretically. The experimental work consisted of subjecting thin-walled tubular steel specimens to cyclic plastic torsion in the presence of sustained axial loads of various magnitudes. The experimental results show that considerable anisotropy is induced when the cyclic shear strains are dominant. Although the true shapes of yield and work-hardening surfaces can be very complex, a mathematical model is presented which includes both anisotropy and Bauschinger effects. The model is able to qualitatively predict the deformation patterns during a cycle of applied plastic shear strain for a range of sustained axial stresses and also indicate the material response to changes in axial stress. (orig.)

  11. Elastic stability of biaxially loaded longitudinally stiffened composite structures.

    Science.gov (United States)

    Viswanathan, A. V.; Tamekuni, M.; Tripp, L. L.

    1973-01-01

    A linear analysis method is presented for the elastic stability of structures of uniform cross section, that may be idealized as an assemblage of laminated plate-strips, flat and curved, and beams. Each plate-strip and beam covers the entire length of the structure and is simply supported on the edges normal to the longitudinal axis. Arbitrary boundary conditions may be specified on any external longitudinal side of plate-strips. The structure or selected plate-strips may be loaded in any desired combination of inplane biaxial loads. The analysis simultaneously considers all modes of instability and is applicable for the buckling of laminated composite structures. Some numerical results are presented to indicate possible applications.

  12. High temperature strength of Hastelloy XR under biaxial stress states

    International Nuclear Information System (INIS)

    Muto, Yasushi; Hada, Kazuhiko; Koikegami, Hajime; Ohno, Nobutada.

    1991-01-01

    Biaxial(tension/torsion) creep and creep-fatigue tests were conducted on Hastelloy XR at 950degC in air. Hastelloy XR is a nickel base solution-annealed heat resistant alloy. Thin-walled tubular test specimens were employed. As results of the creep tests, the von Mises' flow rule was revealed to be applicable very well. Under the torsion load, sufficient growth of voids was necessary to initiate the fracture and this resulted in longer life time compared with that under the tension load. Only a few number of small voids could be observed and very long life times were attained under the compression load. The creep-fatigue tests revealed that superposition of constant torsion load on a cyclic axial load reduced the cycles to failure significantly and the amount of reduction was consistent with the prediction by the linear life fraction rule. (author)

  13. Post-buckling capacity of bi-axially loaded rectangular steel plates

    DEFF Research Database (Denmark)

    Jönsson, Jeppe; Bondum, T. H.

    2012-01-01

    slenderness and edge displacement ratio are included in the investigations presented. Capacity interaction curves are established in the bi-axial stress domain. It turns out that for certain stress ratios the imperfections dominating the ultimate capacity are not affine to the lowest classical buckling mode...... for biaxial stress. It is of great interest that short wave imperfections of a lower magnitude compared to conventionally used imperfections are seen to lower the capacity of the bi-axially loaded plates. The topic is of major concern in the flange plates of long span bridges with multi box girder...

  14. Mastering the biaxial stress state in nanometric thin films on flexible substrates

    Energy Technology Data Exchange (ETDEWEB)

    Faurie, D., E-mail: faurie@univ-paris13.fr [LSPM-CNRS, UPR3407, Université Paris 13, Villetaneuse (France); Renault, P.-O.; Le Bourhis, E. [Institut Pprime UPR3346, CNRS – Université de Poitiers, Futuroscope (France); Geandier, G. [Institut Jean Lamour, CNRS UMR7198, Université de Lorraine, Nancy Cedex (France); Goudeau, P. [Institut Pprime UPR3346, CNRS – Université de Poitiers, Futuroscope (France); Thiaudière, D. [SOLEIL Synchrotron, Saint-Aubin, Gif-Sur-Yvette (France)

    2014-07-01

    Biaxial stress state of thin films deposited on flexible substrate can be mastered thanks to a new biaxial device. This tensile machine allows applying in-plane loads F{sub x} and F{sub y} in the two principal directions x and y of a cruciform-shaped polymer substrate. The transmission of the deformation at film/substrate interface allows controlling the stress and strain field in the thin films. We show in this paper a few illustrations dealing with strain measurements in polycrystalline thin films deposited on flexible substrate. The potentialities of the biaxial device located at Soleil synchrotron are also discussed.

  15. DYNAMIC STRAIN MAPPING AND REAL-TIME DAMAGE STATE ESTIMATION UNDER BIAXIAL RANDOM FATIGUE LOADING

    Data.gov (United States)

    National Aeronautics and Space Administration — DYNAMIC STRAIN MAPPING AND REAL-TIME DAMAGE STATE ESTIMATION UNDER BIAXIAL RANDOM FATIGUE LOADING SUBHASISH MOHANTY*, ADITI CHATTOPADHYAY, JOHN N. RAJADAS, AND CLYDE...

  16. Single-source mechanical loading system produces biaxial stresses in cylinders

    Science.gov (United States)

    Flower, J. F.; Stafford, R. L.

    1967-01-01

    Single-source mechanical loading system proportions axial-to-hoop tension loads applied to cylindrical specimens. The system consists of hydraulic, pneumatic, and lever arrangements which produce biaxial loading ratios.

  17. Failure criterion for graphene in biaxial loading—a molecular dynamics study

    International Nuclear Information System (INIS)

    Yazdani, Hessam; Hatami, Kianoosh

    2015-01-01

    Molecular dynamics simulations are carried out in order to develop a failure criterion for infinite/bulk graphene in biaxial tension. Stresses along the principal edge configurations of graphene (i.e. armchair and zigzag directions) are normalized to the corresponding uniaxial ultimate strength values. The combinations of normalized stresses resulting in the failure of graphene are used to define failure envelopes (limiting stress ratio surfaces). Results indicate that a bilinear failure envelope can be used to represent the tensile strength of graphene in biaxial loading at different temperatures with reasonable accuracy. A circular failure envelope is also introduced for practical applications. Both failure envelopes define temperature-independent upper limits for the feasible combinations of normalized stresses for a graphene sheet in biaxial loading. Predicted failure modes of graphene under biaxial loading are also shown and discussed. (paper)

  18. Local behavior of an AISI 304 stainless steel submitted to in situ biaxial loading in SEM

    Energy Technology Data Exchange (ETDEWEB)

    Caër, C., E-mail: celia.caer@gmail.com; Pesci, R.

    2017-04-06

    The microstructural response of a coarse grained AISI 304 stainless steel submitted to biaxial tensile loading was investigated using SEM and X-ray diffraction. The specimen geometry was designed to allow for biaxial stress state and incipient crack in the center of the active part under biaxial tensile loading. This complex loading was performed step by step by a micromachine fitting into a SEM chamber. At each loading step FSD pictures and EBSD measurements were carried out to study the microstructural evolution of the alloy, namely grain rotations and misorientations, stress-induced martensite formation and crack propagation. According to their initial orientation, grains are found to behave differently under loading. Approximately 60% of grains are shown to reorient to the [110] Z orientation under biaxial tensile loading, whereas the 40% left undergo high plastic deformation. EBSD and XRD measurements respectively performed under loading and on the post mortem specimen highlighted the formation of about 4% of martensite.

  19. Evaluation of micro fatigue crack growth under equi-biaxial stress by membranous pressure fatigue test

    International Nuclear Information System (INIS)

    Iida, Satoshi; Abe, Shigeki; Nakamura, Takao; Kamaya, Masayuki

    2014-01-01

    For preventing nuclear power plant (NPP) accidents, NPPs are required to ensure system safety in long term safe operation under aging degradation. Now, fatigue accumulation is one of major ageing phenomena and are evaluated to ensure safety by design fatigue curve that are based on the results of uniaxial fatigue tests. On the other hand, thermal stress that occurs in piping of actual components is not uniaxial but equi-biaxial. For accurate evaluation, it is required to conform real circumstance. In this study, membranous pressure fatigue test was conducted to simulated equi-biaxial stress. Crack initiation and crack growth were examined by replica investigation. Calculation result of equivalent stress intensity factor shows crack growth under equi-biaxial stress is faster than under uniaxial stress. It is concluded that equi-biaxial fatigue behavior should be considered in the evaluation of fatigue crack initiation and crack growth. (author)

  20. Vacuum welding of metals; Soudage des metaux sous vide

    Energy Technology Data Exchange (ETDEWEB)

    Stohr, J A; Briola, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    This new welding process has been developed by the Commissariat a l'Energie Atomique (CEA) in France. The edges of the work-pieces are melted by the impact of an electron beam produced by an electron gun. Welding is carried out in a vacuum of 10{sup -4} to 10{sup -8} mm of mercury. The welding machine consists, diagrammatically, of: a) a metal enclosure in which a vacuum is produced; b) a cathode for electron emission, a high-voltage generator for accelerating these electrons, a focusing device; c) a mechanical device for moving (rotating) the work-piece. Advantages of the process: 1) possible welding of highly oxidizable metals (e.g. zirconium); 2) fabrication of high-vacuum-sealed metal containers; 3) production of very deeply penetrated welds. Therefore, this new process is particularly advantageous for atomic power applications, the fabrication of electron tubes and, more generally, for all industries in which very special metals are used. (author) [French] Ce procede de soudage a ete recemment mis au point au Commissariat a l'Energie Atomique en France (CEA). Il consiste a utiliser, pour fondre les levres des pieces a souder, l'impact d'un faisceau d'electrons produit par un canon a electrons. Le soudage s'effectue sous un vide de 10{sup -4} a 10{sup -8} mm de mercure. La machine a souder se compose schematiquement: a) d'une enceinte metallique ou l'on fait le vide; b) d'une cathode emettant des electrons, d'un generateur H.T. permettant d'accelerer ces electrons d'un dispositif de focalisation; c) d'un dispositif mecanique permettant le deplacement (rotation) de la piece a souder. Avantages de ce procede: 1) possibilite de souder les metaux tres oxydables (exemple: zirconium); 2) realisation de 'containers' metalliques fermes sous vide pousse; 3) obtention de profondeurs de soudures considerables. Ce nouveau procede est donc particulierement interessant pour l ' energie atomique, la fabrication des tubes electroniques et, en general, toutes les industries

  1. Biaxial loading effects on fracture toughness of reactor pressure vessel steel

    International Nuclear Information System (INIS)

    McAfee, W.J.; Bass, B.R.; Bryson, J.W. Jr.; Pennell, W.E.

    1995-03-01

    The preliminary phases of a program to develop and evaluate fracture methodologies for assessing crack-tip constraint effects on fracture toughness of reactor pressure vessel (RPV) steels have been completed by the Heavy-Section Steel Technology (HSST) Program. Objectives were to investigate effect of biaxial loading on fracture toughness, quantify this effect through existing stress-based, dual-parameter, fracture-toughness correlations, or propose and verify alternate correlations. A cruciform beam specimen with 2-D, shallow, through-thickness flaw and a special loading fixture was designed and fabricated. Tests were performed using biaxial loading ratios of 0:1 (uniaxial), 0.6:1, and 1:1 (equi-biaxial). Critical fracture-toughness values were calculated for each test. Biaxial loading of 0.6:1 resulted in a reduction in the lower bound fracture toughness of ∼12% as compared to that from the uniaxial tests. The biaxial loading of 1:1 yielded two subsets of toughness values; one agreed well with the uniaxial data, while one was reduced by ∼43% when compared to the uniaxial data. Results were evaluated using J-Q theory and Dodds-Anderson (D-A) micromechanical scaling model. The D-A model predicted no biaxial effect, while the J-Q method gave inconclusive results. When applied to the 1:1 biaxial data, these constraint methodologies failed to predict the observed reduction in fracture toughness obtained in one experiment. A strain-based constraint methodology that considers the relationship between applied biaxial load, the plastic zone width in the crack plane, and fracture toughness was formulated and applied successfully to the data. Evaluation of this dual-parameter strain-based model led to the conclusion that it has the capability of representing fracture behavior of RPV steels in the transition region, including the effects of out-of-plane loading on fracture toughness. This report is designated as HSST Report No. 150

  2. Fatigue Test Design: Scenarios for Biaxial Fatigue Testing of a 60-Meter Wind Turbine Blade

    Energy Technology Data Exchange (ETDEWEB)

    Post, Nathan [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-07-01

    Current practice in commercial certification of wind turbine blades is to perform separate flap and lead-lag fatigue tests. The National Renewable Energy Laboratory has been researching and evaluating biaxial fatigue testing techniques and demonstrating various options, typically on smaller-scale test articles at the National Wind Technology Center. This report evaluates some of these biaxial fatigue options in the context of application to a multimegawatt blade certification test program at the Wind Technology Testing Center in Charlestown, Massachusetts.

  3. Fracture assessment of shallow-flaw cruciform beams tested under uniaxial and biaxial loading conditions

    International Nuclear Information System (INIS)

    Bass, B.R.; McAfee, W.J.; Williams, P.T.; Pennell, W.E.

    1999-01-01

    A technology to determine shallow-flaw fracture toughness of reactor pressure vessel (RPV) steels is being developed for application to the safety assessment of RPVs containing postulated shallow surface flaws. Matrices of cruciform beam tests were developed to investigate and quantify the effects of temperature, biaxial loading, and specimen size on fracture initiation toughness of two-dimensional (constant depth), shallow, surface flaws. The cruciform beam specimens were developed at Oak Ridge National Laboratory (ORNL) to introduce a far-field, out-of-plane biaxial stress component in the test section that approximates the nonlinear stresses resulting from pressurized-thermal-shock or pressure-temperature loading of an RPV. Tests were conducted under biaxial load ratios ranging from uniaxial to equibiaxial. These tests demonstrated that biaxial loading can have a pronounced effect on shallow-flaw fracture toughness in the lower transition temperature region for an RPV material. The cruciform fracture toughness data were used to evaluate fracture methodologies for predicting the observed effects of biaxial loading on shallow-flaw fracture toughness. Initial emphasis was placed on assessment of stress-based methodologies, namely, the J-Q formulation, the Dodds-Anderson toughness scaling model, and the Weibull approach. Applications of these methodologies based on the hydrostatic stress fracture criterion indicated an effect of loading-biaxiality on fracture toughness; the conventional maximum principal stress criterion indicated no effect. A three-parameter Weibull model based on the hydrostatic stress criterion is shown to correlate with the experimentally observed biaxial effect on cleavage fracture toughness by providing a scaling mechanism between uniaxial and biaxial loading states. (orig.)

  4. Investigation of the Leak Response of a Carbon-Fiber Laminate Loaded in Biaxial Tension

    Science.gov (United States)

    Jackson, Wade C.; Ratcliffe, James G.

    2013-01-01

    Designers of pressurized structures have been reluctant to use composite materials because of concerns over leakage. Biaxial stress states are expected to be the worst-case loading condition for allowing leakage to occur through microcracks. To investigate the leakage behavior under in-plane biaxial loading, a cruciform composite specimen was designed that would have a relatively large test section with a uniform 1:1 biaxial loading ratio. A 7.6-cm-square test section was desired for future investigations of the leakage response as a result of impact damage. Many iterations of the cruciform specimen were evaluated using finite element analysis to reduce stress concentrations and maximize the size of the uniform biaxial strain field. The final design allowed the specimen to go to relatively high biaxial strain levels without incurring damage away from the test section. The specimen was designed and manufactured using carbon/epoxy fabric with a four-ply-thick, quasi-isotropic, central test section. Initial validation and testing were performed on a specimen without impact damage. The specimen was tested to maximum biaxial strains of approximately 4500micro epsilon without apparent damage. A leak measurement system containing a pressurized cavity was clamped to the test section and used to measure the flow rate through the specimen. The leakage behavior of the specimen was investigated for pressure differences up to 172 kPa

  5. Heat extraction from deep rocks at Soultz-sous-Forets

    International Nuclear Information System (INIS)

    Gerard, A.; Baumgaeriner, J.; Baria, R.

    1996-01-01

    A European coordinated research program for the study of hot-dry-rock systems is in progress at Soultz-sous-Forets (Alsace, France). The aim of this project is the extraction of heat from the granite batholiths distributed along the Rhine graben. The technique used involves important forced water circulations under relatively low-pressures using the natural geologic fractures network. The region concerned extends about 3000 km 2 under both the French and the German territories. The program started in 1987 with preliminary scientific investigations followed by a feasibility study. In December 1995, two deep wells, GPK1 (3600 m) and GPK2 (3900 m) were available and equipped for hydraulic testing. Temperatures encountered can reach 168 C at 3800 m with a geothermal gradient exceeding 3.5 C/100 m below 3600 m. The tests performed have shown that the hydraulic performances of these wells can be considerably improved using a simple well stimulation technique. (J.S.). 1 fig

  6. Monitoring Poisson's ratio of glass fiber reinforced composites as damage index using biaxial Fiber Bragg Grating sensors

    OpenAIRE

    Yılmaz, Çağatay; Yilmaz, Cagatay; Akalın, Çağdaş; Akalin, Cagdas; Kocaman, Esat Selim; Suleman, A.; Yıldız, Mehmet; Yildiz, Mehmet

    2016-01-01

    Damage accumulation in Glass Fiber Reinforced Polymer (GFRP) composites is monitored based on Poisson's ratio measurements for three different fiber stacking sequences subjected to both quasi-static and quasi-static cyclic tensile loadings. The sensor systems utilized include a dual-extensometer, a biaxial strain gage and a novel embedded-biaxial Fiber Bragg Grating (FBG) sensor. These sensors are used concurrently to measure biaxial strain whereby the evolution of Poisson's ratio as a functi...

  7. Shear flow simulations of biaxial nematic liquid crystals

    Science.gov (United States)

    Sarman, Sten

    1997-08-01

    We have calculated the viscosities of a biaxial nematic liquid crystal phase of a variant of the Gay-Berne fluid [J. G. Gay and B. J. Berne, J. Chem. Phys. 74, 3316 (1981)] by performing molecular dynamics simulations. The equations of motion have been augmented by a director constraint torque that fixes the orientation of the directors. This makes it possible to fix them at different angles relative to the stream lines in shear flow simulations. In equilibrium simulations the constraints generate a new ensemble. One finds that the Green-Kubo relations for the viscosities become linear combinations of time correlation function integrals in this ensemble whereas they are complicated rational functions in the conventional canonical ensemble. We have evaluated these Green-Kubo relations for all the shear viscosities and all the twist viscosities. We have also calculated the alignment angles, which are functions of the viscosity coefficients. We find that there are three real alignment angles but a linear stability analysis shows that only one of them corresponds to a stable director orientation. The Green-Kubo results have been cross checked by nonequilibrium shear flow simulations. The results from the different methods agree very well. Finally, we have evaluated the Miesowicz viscosities [D. Baalss, Z. Naturforsch. Teil A 45, 7 (1990)]. They vary by more than 2 orders of magnitude. The viscosity is consequently highly orientation dependent.

  8. Research on self-calibration biaxial autocollimator based on ZYNQ

    Science.gov (United States)

    Guo, Pan; Liu, Bingguo; Liu, Guodong; Zhong, Yao; Lu, Binghui

    2018-01-01

    Autocollimators are mainly based on computers or the electronic devices that can be connected to the internet, and its precision, measurement range and resolution are all defective, and external displays are needed to display images in real time. What's more, there is no real-time calibration for autocollimator in the market. In this paper, we propose a biaxial autocollimator based on the ZYNQ embedded platform to solve the above problems. Firstly, the traditional optical system is improved and a light path is added for real-time calibration. Then, in order to improve measurement speed, the embedded platform based on ZYNQ that combines Linux operating system with autocollimator is designed. In this part, image acquisition, image processing, image display and the man-machine interaction interface based on Qt are achieved. Finally, the system realizes two-dimensional small angle measurement. Experimental results showed that the proposed method can improve the angle measurement accuracy. The standard deviation of the close distance (1.5m) is 0.15" in horizontal direction of image and 0.24"in vertical direction, the repeatability of measurement of the long distance (10m) is improved by 0.12 in horizontal direction of image and 0.3 in vertical direction.

  9. Adaptive fuzzy trajectory control for biaxial motion stage system

    Directory of Open Access Journals (Sweden)

    Wei-Lung Mao

    2016-04-01

    Full Text Available Motion control is an essential part of industrial machinery and manufacturing systems. In this article, the adaptive fuzzy controller is proposed for precision trajectory tracking control in biaxial X-Y motion stage system. The theoretical analyses of direct fuzzy control which is insensitive to parameter uncertainties and external load disturbances are derived to demonstrate the feasibility to track the reference trajectories. The Lyapunov stability theorem has been used to testify the asymptotic stability of the whole system, and all the signals are bounded in the closed-loop system. The intelligent position controller combines the merits of the adaptive fuzzy control with robust characteristics and learning ability for periodic command tracking of a servo drive mechanism. The simulation and experimental results on square, triangle, star, and circle reference contours are presented to show that the proposed controller indeed accomplishes the better tracking performances with regard to model uncertainties. It is observed that the convergence of parameters and tracking errors can be faster and smaller compared with the conventional adaptive fuzzy control in terms of average tracking error and tracking error standard deviation.

  10. Preparation of biaxially oriented TlCu-1234 thin films

    CERN Document Server

    Khan, N A; Tateai, F; Kojima, T; Ishida, K; Terada, N; Ihara, H

    1999-01-01

    The single phase of TlCu-1234 superconductor thin films is prepared for the first time by the amorphous phase epitaxy (APE) method, which is thallium treatment of sputtered amorphous phase at 900 degrees C for 1 h. The amorphous $9 phase is prepared by sputtering from the stoichiometric target composition CuBa/sub 2/Ca/sub 3/Cu/sub 4/O/sub 12-y/. The films on the SrTiO/sub 3/ substrate are aligned biaxially after the thallium treatment. Highly reproducible $9 TlCu-1234 films are prepared by this method. The XRD reflected a predominant single phase with the c-axis lattice constant of 18.74 AA. This lattice constant value is in between that of Cu-1234 (17.99 AA) and Tl-1234 (19.11 AA) . The $9 pole figure measurements of (103) reflection of the films showed a-axis-oriented crystals with Delta phi =0.8 degrees . The composition of the films after energy dispersive X-ray (EDX) measurements is Tl/sub 0.8/Cu/sub 0.2/Ba/sub $9 2/Ca/sub 3/Cu/sub 4/O /sub 12-y/. From the resistivity measurements, the T/sub c/ is 113 K...

  11. Experimental studies of yield phenomena in biaxially loaded metals

    International Nuclear Information System (INIS)

    Hecker, S.S.

    1976-01-01

    Realistic materials properties input represents one of the major limitations in computer stress analysis in the plastic range. Lack of data on the response of many structural materials to multiaxial loading requires modeling plastic behavior. Such models can at best predict the response of a limited class of materials for a limited range of loading. A summary of biaxial plasticity experiments on metals is presented to provide a testing ground for such models and to serve as a reference guide for materials that may be of practical interest. Most of the work has been done on materials assumed to exhibit time-and-pressure-independent plastic flow. Special attention is focused on initial and subsequent yield conditions and stress-strain relations. Some specific examples of material behavior that does not fall within the assumptions of classical plasticity theories are discussed. These include time-dependence as evidenced in creep, cyclic loading and strain-rate effects, pressure dependence, large strain behavior, microstructural changes and failure laws. 15 figures, 277 references

  12. Modeling of biaxial gimbal-less MEMS scanning mirrors

    Science.gov (United States)

    von Wantoch, Thomas; Gu-Stoppel, Shanshan; Senger, Frank; Mallas, Christian; Hofmann, Ulrich; Meurer, Thomas; Benecke, Wolfgang

    2016-03-01

    One- and two-dimensional MEMS scanning mirrors for resonant or quasi-stationary beam deflection are primarily known as tiny micromirror devices with aperture sizes up to a few Millimeters and usually address low power applications in high volume markets, e.g. laser beam scanning pico-projectors or gesture recognition systems. In contrast, recently reported vacuum packaged MEMS scanners feature mirror diameters up to 20 mm and integrated high-reflectivity dielectric coatings. These mirrors enable MEMS based scanning for applications that require large apertures due to optical constraints like 3D sensing or microscopy as well as for high power laser applications like laser phosphor displays, automotive lighting and displays, 3D printing and general laser material processing. This work presents modelling, control design and experimental characterization of gimbal-less MEMS mirrors with large aperture size. As an example a resonant biaxial Quadpod scanner with 7 mm mirror diameter and four integrated PZT (lead zirconate titanate) actuators is analyzed. The finite element method (FEM) model developed and computed in COMSOL Multiphysics is used for calculating the eigenmodes of the mirror as well as for extracting a high order (n system inputs and scanner displacement as system output. By applying model order reduction techniques using MATLABR a compact state space system approximation of order n = 6 is computed. Based on this reduced order model feedforward control inputs for different, properly chosen scanner displacement trajectories are derived and tested using the original FEM model as well as the micromirror.

  13. Al-Ḥudayyda sous occupation ottomane (1849-1918

    Directory of Open Access Journals (Sweden)

    Patrice Chevalier

    2011-12-01

    Full Text Available Petit port de pêche situé sur les côtes de la mer Rouge, al-Ḥudayyda change progressivement de statut et de dimensions avec l’arrivée de l’armée ottomane en 1839. Al-Ḥudayyda se voit alors choisi comme l’un des points stratégiques (militaire et politique du dispositif colonial ottoman.Grâce aux différentes infrastructures mises en place par l’administration ottomane, mais aussi grâce à l’ouverture du canal de Suez en 1869, le village attire peu à peu une population multi-ethnique et cosmopolite venue y commercer ou simplement y trouver refuge, dans un contexte politique régional passablement agité. D’une centaine de Yéménites à l’origine, il compte 42 000 âmes à la veille de la première guerre mondiale.La cohabitation sous administration ottomane va-t-elle générer ou non des échanges ou emprunts entre les différentes communautés ? Les Ottomans vont-ils réussir à transcender les multiples appartenances identitaires au profit d’une appartenance citoyenne à l’empire, comme le prévoit leur ambitieux programme de réformes ? La ville d’al- Ḥudayyda sera-t-elle dotée d’une identité spécifique suffisamment forte pour que les individus appartenant aux différentes communautés présentes s’identifient à la ville ? Voilà quelques-unes des questions auxquelles cet article tente de répondre.

  14. Le sous-titrage : une pratique à la marge de la traduction

    Directory of Open Access Journals (Sweden)

    Dumas, Louise

    2014-12-01

    Full Text Available Le sous-titre interlinguistique est un objet difficile à appréhender théoriquement. S'il permet d'aller d'une langue à une autre, il implique aussi un passage de l'écoute à la lecture et du cinéma à l'écriture. Le caractère interlinguistique est souvent mis en avant pour amener à considérer le sous-titrage comme une traduction. Sa complexité médiologique suggère toutefois qu'il est plus qu'une traduction. En même temps, les fortes contraintes (exigence de brièveté, de lisibilité, de cohérence avec l'image cinématographique auxquelles il est soumis font qu'il est moins qu'une traduction – moins exact, moins long, moins « équivalent » au texte original. Le présent travail se propose de réfléchir de manière théorique aux rapports entre sous-titrage et traduction. Pour ce faire, nous confronterons le sous-titrage aux concepts fondamentaux de la traductologie. Premièrement, le passage de l'oral à l'écrit opéré dans les sous-titres est intimement lié à la distinction traductologique entre traduction et interprétariat. Pour pouvoir condenser les dialogues, résumer leur contenu, le sous-titreur est amené à les interpréter, ce qui permet de souligner l'étroite parenté entre traduction, interprétariat et interprétation. Deuxièmement, les fortes contraintes auxquelles sont soumis les sous-titres invitent à s'interroger sur la notion d'équivalence qui se trouve normalement au principe de toute traduction. Toutes les théories traductologiques insistent sur le fait qu'une équivalence n'est jamais parfaite et que le traducteur privilégie certains niveaux d'équivalence : en poussant à l'extrême cette dynamique de sélection constitutive de l'équivalence, on peut considérer que les sous-titres sont équivalents aux dialogues. En tant que cas limite, le sous-titrage permet de tester les concepts fondamentaux de la traductologie et de définir leurs limites.

  15. Experimental study on ultimate strength and strain behavior of concrete under biaxial compressive stresses

    International Nuclear Information System (INIS)

    Onuma, Hiroshi; Aoyagi, Yukio

    1976-01-01

    The purpose of this investigation was to study the ultimate strength failure mode and deformation behavior of concrete under short-term biaxial compressive stresses, as an aid to design and analyze the concrete structures subjected to multiaxial compression such as prestressed or reinforced concrete vessel structures. The experimental work on biaxial compression was carried out on the specimens of three mix proportions and different ages with 10cm x 10cm x 10cm cubic shape in a room controlled at 20 0 C. The results are summarized as follows. (1) To minimize the surface friction between specimens and loading platens, the pads of teflon sheets coated with silicone grease were used. The coefficient of friction was measured and was 3 percent on the average. (2) The test data showed that the strength of the concrete subjected to biaxial compression increased as compared to uniaxial compressive strength, and that the biaxial strength increase was mainly dependent on the ratio of principal stresses, and it was hardly affected by mix proportions and ages. (3) The maximum increase of strength, which occurred at the stress ratio of approximately sigma 2 /sigma 1 = 0.6, was about 27 percent higher than the uniaxial strength of concrete. (4) The ultimate strength in case of biaxial compression could be approximated by the parabolic equation. (Kako, I.)

  16. Failure analysis based on microvoid growth for sheet metal during uniaxial and biaxial tensile tests

    International Nuclear Information System (INIS)

    Abbassi, Fethi; Mistou, Sebastien; Zghal, Ali

    2013-01-01

    Highlights: ► Cruciform specimen designed and biaxial tensile test carried out. ► Stereo Correlation Image technique is used for 3D full-filed measurements. ► SEM fractography analysis is used to explain the fracture mechanism. ► Constitutive modeling of the necking phenomenon was developed using GTN model. - Abstract: The aim of the presented investigations is to perform an analysis of fracture and instability during simple and complex load testing by addressing the influence of ductile damage evolution in necking processes. In this context, an improved experimental methodology was developed and successfully used to evaluate localization of deformation during uniaxial and biaxial tensile tests. The biaxial tensile tests are carried out using cruciform specimen loaded using a biaxial testing machine. In this experimental investigation, Stereo-Image Correlation technique has is used to produce the heterogeneous deformations map within the specimen surface. Scanning electron microscope is used to evaluate the fracture mechanism and the micro-voids growth. A finite element model of uniaxial and biaxial tensile tests are developed, where a ductile damage model Gurson–Tvergaard–Needleman (GTN) is used to describe material deformation involving damage evolution. Comparison between the experimental and the simulation results show the accuracy of the finite element model to predict the instability phenomenon. The advanced measurement techniques contribute to understand better the ductile fracture mechanism

  17. Control of biaxial strain in single-layer molybdenite using local thermal expansion of the substrate

    Science.gov (United States)

    Plechinger, Gerd; Castellanos-Gomez, Andres; Buscema, Michele; van der Zant, Herre S. J.; Steele, Gary A.; Kuc, Agnieszka; Heine, Thomas; Schüller, Christian; Korn, Tobias

    2015-03-01

    Single-layer MoS2 is a direct-gap semiconductor whose electronic band structure strongly depends on the strain applied to its crystal lattice. While uniaxial strain can be easily applied in a controlled way, e.g., by bending of a flexible substrate with the atomically thin MoS2 layer on top, experimental realization of biaxial strain is more challenging. Here, we exploit the large mismatch between the thermal expansion coefficients of MoS2 and a silicone-based substrate to apply a controllable biaxial tensile strain by heating the substrate with a focused laser. The effect of this biaxial strain is directly observable in optical spectroscopy as a redshift of the MoS2 photoluminescence. We also demonstrate the potential of this method to engineer more complex strain patterns by employing highly absorptive features on the substrate to achieve non-uniform heat profiles. By comparison of the observed redshift to strain-dependent band structure calculations, we estimate the biaxial strain applied by the silicone-based substrate to be up to 0.2%, corresponding to a band gap modulation of 105 meV per percentage of biaxial tensile strain.

  18. Shape recovery characteristics of biaxially prestrained Fe-Mn-Si-based shape memory alloy

    International Nuclear Information System (INIS)

    Wada, M.; Naoi, H.; Yasuda, H.; Maruyama, T.

    2008-01-01

    Fe-Mn-Si-based shape memory alloy has already been used practically for steel pipe joints. In most of the applications including the steel pipe joints, it is possible to estimate the reduction of diameter from the experimental data of the shape recovery after uniaxial stretching of the alloy materials. However, studies on shape recovery effects after biaxial stretching are important for the extensive applications of the alloy. In this study, we investigated the shape recovery strain after uniaxial and biaxial stretching and the microstructures of the alloy in order to see the effects of uniaxial and biaxial prestrain on the stress-induced martensitic transformation. Amounts of shape recovery strain in the biaxially prestrained specimens are smaller than those in the uniaxially prestrained specimens. Transmission electron microscopy revealed that reverse transformations of stress-induced martensitic ε-phase are prevented by slip bands formed at the same time in the biaxially prestrained specimens, but not in the uniaxially prestrained specimens. The technological data and interpretations presented in this study should be useful in forming design guidelines for promoting the extensive applications of Fe-Mn-Si-based shape memory alloy

  19. Nondestructive measurement of esophageal biaxial mechanical properties utilizing sonometry

    Science.gov (United States)

    Aho, Johnathon M.; Qiang, Bo; Wigle, Dennis A.; Tschumperlin, Daniel J.; Urban, Matthew W.

    2016-07-01

    Malignant esophageal pathology typically requires resection of the esophagus and reconstruction to restore foregut continuity. Reconstruction options are limited and morbid. The esophagus represents a useful target for tissue engineering strategies based on relative simplicity in comparison to other organs. The ideal tissue engineered conduit would have sufficient and ideally matched mechanical tolerances to native esophageal tissue. Current methods for mechanical testing of esophageal tissues both in vivo and ex vivo are typically destructive, alter tissue conformation, ignore anisotropy, or are not able to be performed in fluid media. The aim of this study was to investigate biomechanical properties of swine esophageal tissues through nondestructive testing utilizing sonometry ex vivo. This method allows for biomechanical determination of tissue properties, particularly longitudinal and circumferential moduli and strain energy functions. The relative contribution of mucosal-submucosal layers and muscular layers are compared to composite esophagi. Swine thoracic esophageal tissues (n  =  15) were tested by pressure loading using a continuous pressure pump system to generate stress. Preconditioning of tissue was performed by pressure loading with the pump system and pre-straining the tissue to in vivo length before data was recorded. Sonometry using piezocrystals was utilized to determine longitudinal and circumferential strain on five composite esophagi. Similarly, five mucosa-submucosal and five muscular layers from thoracic esophagi were tested independently. This work on esophageal tissues is consistent with reported uniaxial and biaxial mechanical testing and reported results using strain energy theory and also provides high resolution displacements, preserves native architectural structure and allows assessment of biomechanical properties in fluid media. This method may be of use to characterize mechanical properties of tissue engineered esophageal

  20. Tuning magnetism by biaxial strain in native ZnO.

    Science.gov (United States)

    Peng, Chengxiao; Wang, Yuanxu; Cheng, Zhenxiang; Zhang, Guangbiao; Wang, Chao; Yang, Gui

    2015-07-07

    Magnetic ZnO, one of the most important diluted magnetic semiconductors (DMS), has attracted great scientific interest because of its possible technological applications in optomagnetic devices. Magnetism in this material is usually delicately tuned by the doping level, dislocations, and local structures. The rational control of magnetism in ZnO is a highly attractive approach for practical applications. Here, the tuning effect of biaxial strain on the d(0) magnetism of native imperfect ZnO is demonstrated through first-principles calculations. Our calculation results show that strain conditions have little effect on the defect formation energy of Zn and O vacancies in ZnO, but they do affect the magnetism significantly. For a cation vacancy, increasing the compressive strain will obviously decrease its magnetic moment, while tensile strain cannot change the moment, which remains constant at 2 μB. For a singly charged anion vacancy, however, the dependence of the magnetic moment on strain is opposite to that of the Zn vacancy. Furthermore, the ferromagnetic state is always present, irrespective of the strain type, for ZnO with two zinc vacancies, 2VZns. A large tensile strain is favorable for improving the Curie temperature and realizing room temperature ferromagnetism for ZnO-based native semiconductors. For ZnO with two singly charged oxygen vacancies, 2Vs, no ferromagnetic ordering can be observed. Our work points the way to the rational design of materials beyond ZnO with novel non-intrinsic functionality by simply tuning the strain in a thin film form.

  1. Bandgap-customizable germanium using lithographically determined biaxial tensile strain for silicon-compatible optoelectronics.

    Science.gov (United States)

    Sukhdeo, David S; Nam, Donguk; Kang, Ju-Hyung; Brongersma, Mark L; Saraswat, Krishna C

    2015-06-29

    Strain engineering has proven to be vital for germanium-based photonics, in particular light emission. However, applying a large permanent biaxial tensile strain to germanium has been a challenge. We present a simple, CMOS-compatible technique to conveniently induce a large, spatially homogenous strain in circular structures patterned within germanium nanomembranes. Our technique works by concentrating and amplifying a pre-existing small strain into a circular region. Biaxial tensile strains as large as 1.11% are observed by Raman spectroscopy and are further confirmed by photoluminescence measurements, which show enhanced and redshifted light emission from the strained germanium. Our technique allows the amount of biaxial strain to be customized lithographically, allowing the bandgaps of different germanium structures to be independently customized in a single mask process.

  2. Phonon deformation potentials of hexagonal GaN studied by biaxial stress modulation

    Directory of Open Access Journals (Sweden)

    Jun-Yong Lu

    2011-09-01

    Full Text Available In this work, a biaxial stress modulation method, combining the microfabrication technique, finite element analysis and a weighted averaging process, was developed to study piezospectroscopic behavior of hexagonal GaN films, epitaxially grown by metalorganic chemical vapor deposition on c-sapphire and Si (111 substrates. Adjusting the size of patterned islands, various biaxial stress states could be obtained at the island centers, leading to abundant stress-Raman shift data. With the proposed stress modulation method, the Raman biaxial stress coefficients of E2H and A1 (LO phonons of GaN were determined to be 3.43 cm-1/GPa and 2.34 cm-1/GPa, respectively.

  3. STRAIN-CONTROLLED BIAXIAL TENSION OF NATURAL RUBBER: NEW EXPERIMENTAL DATA

    KAUST Repository

    Pancheri, Francesco Q.

    2014-03-01

    We present a new experimental method and provide data showing the response of 40A natural rubber in uniaxial, pure shear, and biaxial tension. Real-time biaxial strain control allows for independent and automatic variation of the velocity of extension and retraction of each actuator to maintain the preselected deformation rate within the gage area of the specimen. Wealso focus on the Valanis-Landel hypothesis that is used to verify and validate the consistency of the data.Weuse a threeterm Ogden model to derive stress-stretch relations to validate the experimental data. The material model parameters are determined using the primary loading path in uniaxial and equibiaxial tension. Excellent agreement is found when the model is used to predict the response in biaxial tension for different maximum in-plane stretches. The application of the Valanis-Landel hypothesis also results in excellent agreement with the theoretical prediction.

  4. A proposal of parameter to predict biaxial fatigue life for CF8M cast stainless steels

    International Nuclear Information System (INIS)

    Park, Joong Cheul; Kwon, Jae Do

    2005-01-01

    Biaxial low cycle fatigue test was carried out to predict fatigue life under combined axial-torsional loading condition which is that of in-phase and out-of-phase for CF8M cast stainless steels. Fatemi Socie(FS) parameter which is based on critical plane approach is not only one of methods but also the best method that can predict fatigue life under biaxial loading condition. But the result showed that, biaxial fatigue life prediction by using FS parameter with several different parameters for the CF8M cast stainless steels is not conservative but best results. So in this present research, we proposed new fatigue life prediction parameter considering effective shear stress instead of FS parameter which considers the maximum normal stress acting on maximum shear strain and its effectiveness was verified

  5. Discrete Element Simulations and Experiments on the Deformation of Cohesive Powders in a Bi-Axial Box

    NARCIS (Netherlands)

    Imole, Olukayode Isaiah; Kumar, Nishant; Magnanimo, Vanessa; Luding, Stefan

    2012-01-01

    We compare element test experiments and simulations on the deformation of frictional, cohesive particles in a bi-axial box. We show that computer simulations with the Discrete Element Method qualitatively reproduce a uniaxial compression element test in the true bi-axial tester. We highlight the

  6. Biaxial Stretch Improves Elastic Fiber Maturation, Collagen Arrangement, and Mechanical Properties in Engineered Arteries.

    Science.gov (United States)

    Huang, Angela H; Balestrini, Jenna L; Udelsman, Brooks V; Zhou, Kevin C; Zhao, Liping; Ferruzzi, Jacopo; Starcher, Barry C; Levene, Michael J; Humphrey, Jay D; Niklason, Laura E

    2016-06-01

    Tissue-engineered blood vessels (TEVs) are typically produced using the pulsatile, uniaxial circumferential stretch to mechanically condition and strengthen the arterial grafts. Despite improvements in the mechanical integrity of TEVs after uniaxial conditioning, these tissues fail to achieve critical properties of native arteries such as matrix content, collagen fiber orientation, and mechanical strength. As a result, uniaxially loaded TEVs can result in mechanical failure, thrombus, or stenosis on implantation. In planar tissue equivalents such as artificial skin, biaxial loading has been shown to improve matrix production and mechanical properties. To date however, multiaxial loading has not been examined as a means to improve mechanical and biochemical properties of TEVs during culture. Therefore, we developed a novel bioreactor that utilizes both circumferential and axial stretch that more closely simulates loading conditions in native arteries, and we examined the suture strength, matrix production, fiber orientation, and cell proliferation. After 3 months of biaxial loading, TEVs developed a formation of mature elastic fibers that consisted of elastin cores and microfibril sheaths. Furthermore, the distinctive features of collagen undulation and crimp in the biaxial TEVs were absent in both uniaxial and static TEVs. Relative to the uniaxially loaded TEVs, tissues that underwent biaxial loading remodeled and realigned collagen fibers toward a more physiologic, native-like organization. The biaxial TEVs also showed increased mechanical strength (suture retention load of 303 ± 14.53 g, with a wall thickness of 0.76 ± 0.028 mm) and increased compliance. The increase in compliance was due to combinatorial effects of mature elastic fibers, undulated collagen fibers, and collagen matrix orientation. In conclusion, biaxial stretching is a potential means to regenerate TEVs with improved matrix production, collagen organization, and mechanical

  7. The fabrication and high temperature stability of biaxially textured Ni tape by ion beam structure modification method

    International Nuclear Information System (INIS)

    Wu, K.; Wang, S.S.; Meng, J.; Han, Z.

    2004-01-01

    For the conventional rolling assisted biaxially textured metallic substrate (RABiTS) process, a large degree of cold rolling deformation and a subsequent high temperature annealing procedure are required to obtain adequately biaxially textured Ni tape. Recently, we have reported a newly developed process, named as ion beam structure modification (ISM), for fabricating biaxially textured Ni tape by use of low energy argon ion beam bombardment. In this paper, the biaxial texture of ISM processed Ni tape and its thermal stability at high temperatures are investigated. Results show that Ni tape processed under optimum ISM conditions, the (2 0 0) rocking curve FWHM is less than 5.7 deg. , and the (1 1 1) phi-scan FWHM is less than 7.5 deg. . High temperature annealing does not impair the biaxial-texture already developed in ISM processed Ni foils, although ISMs should not be regarded as a complete equilibrium process

  8. Crack modelling for the assessment of stiffness loss of reinforced concrete structures under mechanical loading - determination of the permeability of the micro-cracked body; Modelisation de la fissuration pour l'evaluation de la perte d'etancheite des structures en beton arme sous chargements mecaniques

    Energy Technology Data Exchange (ETDEWEB)

    Bongue Boma, M

    2007-12-15

    We propose a model describing the evolution of mechanical and permeability properties of concrete under slow mechanical loading. Calling upon the theory of continua with microstructure, the kinematic of the domain is enriched by a variable characterising size and orientation of the crack field. We call upon configurational forces to deal with crack propagation and we determine the balance equations governing both strain and propagation. The geometry of the microstructure is representative of the porous media: the permeability is obtained from the resolution of Stokes equations in an elementary volume. An example has been treated: we considered simple assumptions (uniform crack field, application of linear fracture mechanics...) and we determined the behaviour of a body under tensile loading. Strain, crack propagation and stiffness loss are completely assessed. Finally the evolution of permeability is plotted: once activated, crack propagation is the main cause of water tightness loss. (author)

  9. Crack modelling for the assessment of stiffness loss of reinforced concrete structures under mechanical loading - determination of the permeability of the micro-cracked body; Modelisation de la fissuration pour l'evaluation de la perte d'etancheite des structures en beton arme sous chargements mecaniques

    Energy Technology Data Exchange (ETDEWEB)

    Bongue Boma, M

    2007-12-15

    We propose a model describing the evolution of mechanical and permeability properties of concrete under slow mechanical loading. Calling upon the theory of continua with microstructure, the kinematic of the domain is enriched by a variable characterising size and orientation of the crack field. We call upon configurational forces to deal with crack propagation and we determine the balance equations governing both strain and propagation. The geometry of the microstructure is representative of the porous media: the permeability is obtained from the resolution of Stokes equations in an elementary volume. An example has been treated: we considered simple assumptions (uniform crack field, application of linear fracture mechanics...) and we determined the behaviour of a body under tensile loading. Strain, crack propagation and stiffness loss are completely assessed. Finally the evolution of permeability is plotted: once activated, crack propagation is the main cause of water tightness loss. (author)

  10. Development of Pangasius steaks by improved sous-vide technology and its process optimization.

    Science.gov (United States)

    Kumari, Namita; Singh, Chongtham Baru; Kumar, Raushan; Martin Xavier, K A; Lekshmi, Manjusha; Venkateshwarlu, Gudipati; Balange, Amjad K

    2016-11-01

    The present study embarked on the objective of optimizing improved sous - vide processing condition for development of ready-to-cook Pangasius steaks with extended shelf-life using response surface methodology. For the development of improved sous - vide cooked product, Pangasius steaks were treated with additional hurdles in various combinations for optimization. Based on the study, suitable combination of chitosan and spices was selected which enhanced antimicrobial and oxidative stability of the product. The Box-Behnken experimental design with 15 trials per model was adopted for designing the experiment to know the effect of independent variables, namely chitosan concentration (X 1 ), cooking time (X 2 ) and cooking temperature (X 3 ) on dependent variable i.e. TBARS value (Y 1 ). From RSM generated model, the optimum condition for sous - vide processing of Pangasius steaks were 1.08% chitosan concentration, 70.93 °C of cooking temperature and 16.48 min for cooking time and predicted minimum value of multiple response optimal condition was Y = 0.855 mg MDA/Kg of fish. The high correlation coefficient (R 2  = 0.975) between the model and the experimental data showed that the model was able to efficiently predict processing condition for development of sous - vide processed Pangasius steaks. This research may help the processing industries and Pangasius fish farmer as it provides an alternative low cost technology for the proper utilization of Pangasius .

  11. Plastic deformation and fracture behavior of zircaloy-2 fuel cladding tubes under biaxial stress

    International Nuclear Information System (INIS)

    Maki, Hideo; Ooyama, Masatosi

    1975-01-01

    Various combinations of biaxial stress were applied on five batches of recrystallized zircaloy-2 fuel cladding tubes with different textures; elongation in both axial and circumferential directions of the specimen was measured continuously up to 5% plastic deformation. The anisotropic theory of plasticity proposed by Hill was applied to the resulting data, and anisotropy constants were obtained through the two media of plastic strain loci and plastic strain ratios. Comparison of the results obtained with the two methods proved that the plastic strain loci provide data that are more effective in predicting quantitatively the plastic deformation behavior of the zircaloy-2 tubes. The anisotropy constants change their value with progress of plastic deformation, and judicious application of the effective stress and effective strain obtained on anisotropic materials will permit the relationship between stress and strain under various biaxialities of stresses to be approximated by the work hardening law. The test specimens used in the plastic deformation experiments were then stressed to fracture under the same combination of biaxial stress as in the proceeding experiments, and the deformation in the fractured part was measured. The result proved that the tilt angle of the c-axis which serves as the index of texture is related to fracture ductility under biaxial stress. Based on this relationship, it was concluded that material with a tilt angle ranging from 10 0 to 15 0 is the most suitable for fuel cladding tubes, from the viewpoint of fracture ductility, at least in the case of unirradiated material. (auth.)

  12. Accessible switching of electronic defect type in SrTi O3 via biaxial strain

    Science.gov (United States)

    Chi, Yen-Ting; Youssef, Mostafa; Sun, Lixin; Van Vliet, Krystyn J.; Yildiz, Bilge

    2018-05-01

    Elastic strain is used widely to alter the mobility of free electronic carriers in semiconductors, but a predictive relationship between elastic lattice strain and the extent of charge localization of electronic defects is still underdeveloped. Here we considered SrTi O3 , a prototypical perovskite as a model functional oxide for thin film electronic devices and nonvolatile memories. We assessed the effects of biaxial strain on the stability of electronic defects at finite temperature by combining density functional theory (DFT) and quasiharmonic approximation (QHA) calculations. We constructed a predominance diagram for free electrons and small electron polarons in this material, as a function of biaxial strain and temperature. We found that biaxial tensile strain in SrTi O3 can stabilize the small polaron, leading to a thermally activated and slower electronic transport, consistent with prior experimental observations on SrTi O3 and distinct from our prior theoretical assessment of the response of SrTi O3 to hydrostatic stress. These findings also resolved apparent conflicts between prior atomistic simulations and conductivity experiments for biaxially strained SrTi O3 thin films. Our computational approach can be extended to other functional oxides, and for the case of SrTi O3 our findings provide concrete guidance for conditions under which strain engineering can shift the electronic defect type and concentration to modulate electronic transport in thin films.

  13. Research on Design and Simulation of Biaxial Tensile-Bending Complex Mechanical Performance Test Apparatus

    Directory of Open Access Journals (Sweden)

    Hailian Li

    2017-09-01

    Full Text Available In order to realize a micro-mechanic performance test of biaxial tensile-bending-combined loading and solve the problem of incompatibility of test apparatus and observation apparatus, novel biaxial-combined tensile-bending micro-mechanical performance test apparatus was designed. The working principle and major functions of key constituent parts of test apparatus, including the servo drive unit, clamping unit and test system, were introduced. Based on the finite element method, biaxial tensile and tension-bending-combined mechanical performances of the test-piece were studied as guidance to learn the distribution of elastic deformation and plastic deformation of all sites of the test-piece and to better plan test regions. Finally, this test apparatus was used to conduct a biaxial tensile test under different pre-bending loading and a tensile test at different rates; the image of the fracture of the test-piece was acquired by a scanning electron microscope and analyzed. It was indicated that as the pre-bending force rises, the elastic deformation phase would gradually shorten and the slope of the elastic deformation phase curve would slightly rise so that a yield limit would appear ahead of time. Bending speed could exert a positive and beneficial influence on tensile strength but weaken fracture elongation. If bending speed is appropriately raised, more ideal anti-tensile strength could be obtained, but fracture elongation would decline.

  14. Crack under biaxial loading: Two-parameter description and prediction of crack growth direction

    Czech Academy of Sciences Publication Activity Database

    Seitl, Stanislav

    2014-01-01

    Roč. 31, APR (2014), s. 44-49 ISSN 0213-3725 R&D Projects: GA MŠk(CZ) 7AMB14AT012 Institutional support: RVO:68081723 Keywords : Concrete * T-stress * cracks growth prediction * numerical calculation * biaxial loading Subject RIV: JL - Materials Fatigue, Friction Mechanics

  15. Biaxial loading and shallow-flaw effects on crack-tip constraint and fracture-toughness

    International Nuclear Information System (INIS)

    Pennell, W.E.; Bass, B.R.; Bryson, J.W.; McAfee, W.J.; Theiss, T.J.; Rao, M.C.

    1993-01-01

    Uniaxial tests of single-edged notched bend (SENB) specimens with both deep- and shallow-flaws have shown elevated fracture-toughness for the shallow flaws. The elevation in fracture-toughness for shallow flaws has been shown to be the result of reduced constraint at the crack-tip. Biaxial loading has the potential to increase constraint at the crack-tip and thereby reduce some of the shallow-flaw, fracture-toughness elevation. Biaxial fracture-toughness tests have shown that the shallow-flaw, fracture-toughness elevation is reduced but not eliminated by biaxial loading. Dual-parameter, fracture-toughness correlations have been proposed to reflect the effect of crack-tip constraint on fracture-toughness. Test results from the uniaxial and biaxial tests were analyzed using the dual-parameter technology. Discrepancies between analysis results and cleavage initiation site data from fractographic examinations indicate that the analysis models are in need of further refinement. Addition of a precleavage, ductile-tearing element to the analysis model has the potential to resolve the noted discrepancies

  16. 2D nonlocal versus 3D bifurcation studies for biaxially loaded plates

    DEFF Research Database (Denmark)

    Benallal, A.; Tvergaard, Viggo

    1998-01-01

    The main objective of this work is to analyse how a two-dimensional second gradient plasticity model is able to reproduce the three-dimensional bifurcation behaviour for a biaxially loaded flat plate. While it is found that the simple model used here is able to capture them qualitatively for the ...

  17. Studies of biaxial mechanical properties and nonlinear finite element modeling of skin.

    Science.gov (United States)

    Shang, Xituan; Yen, Michael R T; Gaber, M Waleed

    2010-06-01

    The objective of this research is to conduct mechanical property studies of skin from two individual but potentially connected aspects. One is to determine the mechanical properties of the skin experimentally by biaxial tests, and the other is to use the finite element method to model the skin properties. Dynamic biaxial tests were performed on 16 pieces of abdominal skin specimen from rats. Typical biaxial stress-strain responses show that skin possesses anisotropy, nonlinearity and hysteresis. To describe the stress-strain relationship in forms of strain energy function, the material constants of each specimen were obtained and the results show a high correlation between theory and experiments. Based on the experimental results, a finite element model of skin was built to model the skin's special properties including anisotropy and nonlinearity. This model was based on Arruda and Boyce's eight-chain model and Bischoff et al.'s finite element model of skin. The simulation results show that the isotropic, nonlinear eight-chain model could predict the skin's anisotropic and nonlinear responses to biaxial loading by the presence of an anisotropic prestress state.

  18. Mechanical properties of biaxially strained poly(L-lactide) tubes: Strain rate and temperature dependence

    DEFF Research Database (Denmark)

    Løvdal, Alexandra Liv Vest; Andreasen, Jens Wenzel; Mikkelsen, Lars Pilgaard

    2017-01-01

    Poly(l-lactide) (PLLA) is a bioabsorbable polymer with high stiffness and strength compared to the other commercially available bioabsorbable polymers. The properties of PLLA can be improved by straining, causing deformation-mediated molecular orientation. PLLA tubes were biaxially strained above...

  19. Biaxial flexural strength of Turkom-Cera core compared to two other all-ceramic systems

    Directory of Open Access Journals (Sweden)

    Bandar Mohammed Abdullah Al-Makramani

    2010-12-01

    Full Text Available Advances in all-ceramic systems have established predictable means of providing metal-free aesthetic and biocompatible materials. These materials must have sufficient strength to be a practical treatment alternative for the fabrication of crowns and fixed partial dentures. OBJECTIVES: The aim of this study was to compare the biaxial flexural strength of three core ceramic materials. MATERIAL AND METHODS: Three groups of 10 disc-shaped specimens (16 mm diameter x 1.2 mm thickness - in accordance with ISO-6872, 1995 were made from the following ceramic materials: Turkom-Cera Fused Alumina [(Turkom-Ceramic (M Sdn Bhd, Puchong, Selangor, Malaysia], In-Ceram (Vita Zahnfabrik, Bad Säckingen, Baden-Württemberg, Germany and Vitadur-N (Vita Zahnfabrik, Bad Säckingen, Baden-Württemberg, Germany, which were sintered according to the manufacturer's recommendations. The specimens were subjected to biaxial flexural strength test in an universal testing machine at a crosshead speed of 0.5 mm/min. The definitive fracture load was recorded for each specimen and the biaxial flexural strength was calculated from an equation in accordance with ISO-6872. RESULTS: The mean biaxial flexural strength values were: Turkom-Cera: 506.8±87.01 MPa, In-Ceram: 347.4±28.83 MPa and Vitadur-N: 128.7±12.72 MPa. The results were analyzed by the Levene's test and Dunnett's T3 post-hoc test (SPSS software V11.5.0 for Windows, SPSS, Chicago, IL, USA at a preset significance level of 5% because of unequal group variances (P<0.001. There was statistically significant difference between the three core ceramics (P<0.05. Turkom-Cera showed the highest biaxial flexural strength, followed by In-Ceram and Vitadur-N. CONCLUSIONS: Turkom-Cera core had significantly higher flexural strength than In-Ceram and Vitadur-N ceramic core materials.

  20. Experimental and analytical comparison of constraint effects due to biaxial loading and shallow-flaws

    International Nuclear Information System (INIS)

    Theiss, T.J.; Bass, B.R.; Bryson, J.W.

    1993-01-01

    A program to develop and evaluate fracture methodologies for the assessment of crack-tip constraint effects on fracture toughness of reactor pressure vessel (RPV) steels has been initiated in the Heavy-Section Steel Technology (HSST) Program. The focus of studies described herein is on the evaluation of a micromechanical scaling model based on critical stressed volumes for quantifying crack-tip constraint through applications to experimental data. Data were utilized from single-edge notch bend (SENB) specimens and HSST-developed cruciform beam specimens that were tested in HSST shallow-crack and biaxial testing programs. Shallow-crack effects and far-field tensile out-of-plane biaxial loading have been identified as constraint issues that influence both fracture toughness and the extent of the toughness scatter band. Results from applications indicate that the micromechanical scaling model can be used successfully to interpret experimental data from the shallow- and deep-crack SENB specimen tests. When applied to the uniaxially and biaxially loaded cruciform specimens, the two methodologies showed some promising features, but also raised several questions concerning the interpretation of constraint conditions in the specimen based on near-tip stress fields. Crack-tip constraint analyses of the shallow-crack cruciform specimen based on near-tip stress fields. Crack-tip constraint analyses of the shallow-crack cruciform specimen subjected to uniaxial or biaxial loading conditions are shown to represent a significant challenge for these methodologies. Unresolved issued identified from these analyses require resolution as part of a validation process for biaxial loading applications

  1. Une localisation exceptionnelle de la tuberculose vertébrale Mal de Pott sous-occipital

    Science.gov (United States)

    Yahyaoui, Sana; Majdoub, Senda; Zaghouani, Houneida; Fradj, Hosni Ben; Bakir, Dejla; Bouajina, Elyes; Kraiem, Chakib

    2013-01-01

    Le mal de Pott est la forme la plus commune de la tuberculose osseuse touchant essentiellement le rachis dorso-lombaire. La localisation sous-occipitale reste exceptionnelle. Le diagnostic de cette entité est le plus souvent tardif ce qui expose à des complications graves. Les radiographies standard ne sont parlantes qu’à un stade tardif de la maladie, d'où l'intérêt de l'imagerie moderne notamment la tomodensitométrie (TDM) et l'imagerie par résonance magnétique (IRM) qui permettent un diagnostic précoce. Nous rapportons un nouveau cas de tuberculose sous-occipitale. Le diagnostic était posé sur l'imagerie en coupe et confirmé histologiquement à la biopsie transorale. Sont rappelés les aspects en imagerie de cette localisation particulière du mal de Pott. PMID:23819005

  2. Spécificités du sous-titrage pour enfants malentendants

    OpenAIRE

    Comitre-Narvaez, Isabel

    2016-01-01

    Ce travail aborde la spécificité multisémiotique du texte audiovisuel qui est à l’origine de nombreux défis que le traducteur audiovisuel doit relever. Il explore les rapports intersémiotiques qui s’établissent entre le code verbal et le code visuel et se concentre sur les particularités du sous-titrage pour sourds et malentendants dans la “compensation” du déficit auditif, essentiellement son rapport spécifique à l’image. À cet égard, Gottlieb signale que le succès du sous-titrage dépend du ...

  3. Room temperature growth of biaxially aligned yttria-stabilized zirconia films on glass substrates by pulsed-laser deposition

    CERN Document Server

    Li Peng; Mazumder, J

    2003-01-01

    Room temperature deposition of biaxially textured yttria-stabilized zirconia (YSZ) films on amorphous glass substrates was successfully achieved by conventional pulsed-laser deposition. The influence of the surrounding gases, their pressure and the deposition time on the structure of the films was studied. A columnar growth process was revealed based on the experimental results. The grown biaxial texture appears as a kind of substrate independence, which makes it possible to fabricate in-plane aligned YSZ films on various substrates.

  4. Fracture assessment of HSST Plate 14 shallow-flaw cruciform bend specimens tested under biaxial loading conditions

    Energy Technology Data Exchange (ETDEWEB)

    Bass, B.R.; McAfee, W.J.; Williams, P.T.; Pennell, W.E.

    1998-06-01

    A technology to determine shallow-flaw fracture toughness of reactor pressure vessel (RPV) steels is being developed for application to the safety assessment of RPVs containing postulated shallow surface flaws. Matrices of cruciform beam tests were developed to investigate and quantify the effects of temperature, biaxial loading, and specimen size on fracture initiation toughness of two-dimensional (constant depth), shallow, surface flaws. The cruciform beam specimens were developed at Oak Ridge National Laboratory (ORNL) to introduce a far-field, out-of-plane biaxial stress component in the test section that approximates the nonlinear stresses resulting from pressurized-thermal-shock or pressure-temperature loading of an RPV. Tests were conducted under biaxial load ratios ranging from uniaxial to equibiaxial. These tests demonstrated that biaxial loading can have a pronounced effect on shallow-flaw fracture toughness in the lower transition temperature region for an RPV material. The cruciform fracture toughness data were used to evaluate fracture methodologies for predicting the observed effects of biaxial loading on shallow-flaw fracture toughness. Initial emphasis was placed on assessment of stress-based methodologies, namely, the J-Q formulation, the Dodds-Anderson toughness scaling model, and the Weibull approach. Applications of these methodologies based on the hydrostatic stress fracture criterion indicated an effect of loading-biaxiality on fracture toughness; the conventional maximum principal stress criterion indicated no effect. A three-parameter Weibull model based on the hydrostatic stress criterion is shown to correlate the experimentally observed biaxial effect on cleavage fracture toughness by providing a scaling mechanism between uniaxial and biaxial loading states.

  5. Profil lipidique des personnes vivant avec le VIH sous antirétroviral ...

    African Journals Online (AJOL)

    Au regard des connaissances actuelles, aucune étude n'est disponible au Bénin sur le profil lipidique des personnes vivant avec le VIH. L'objectif de la présente étude est de décrire le profil lipidique des personnes vivant avec le VIH sous antirétroviral suivies au CHU-O/P de Porto-Novo. Il s'est agi d'une étude ...

  6. statut de la matiere organique des cambisols et des lixisols sous

    African Journals Online (AJOL)

    Administrateur

    L'étude vise à évaluer la matière organique des Cambisols et des Lixisols sous formations naturelles de longue durée en zone climatique nord-soudanienne et à établir, les relations entre ... sont supérieures à celles des sols des zones sahélienne et sud-soudanienne. ... globale a eu une corrélation positive avec le pH.

  7. Evaluation of constraint methodologies applied to a shallow-flaw cruciform bend specimen tested under biaxial loading conditions

    International Nuclear Information System (INIS)

    Bass, B.R.; McAfee, W.J.; Williams, P.T.; Pennell, W.E.

    1998-01-01

    A technology to determine shallow-flaw fracture toughness of reactor pressure vessel (RPV) steels is being developed for application to the safety assessment of RPVs containing postulated shallow surface flaws. Matrices of cruciform beam tests were developed to investigate and quantify the effects of temperature, biaxial loading, and specimen size on fracture initiation toughness of two-dimensional (constant depth), shallow surface flaws. The cruciform beam specimens were developed at Oak Ridge National Laboratory (ORNL) to introduce a prototypic, far-field. out-of-plane biaxial stress component in the test section that approximates the nonlinear stresses resulting from pressurized-thermal-shock or pressure-temperature loading of an RPV. Tests were conducted under biaxial load ratios ranging from uniaxial to equibiaxial. These tests demonstrated that biaxial loading can have a pronounced effect on shallow-flaw fracture toughness in the lower transition temperature region for RPV materials. The cruciform fracture toughness data were used to evaluate fracture methodologies for predicting the observed effects of biaxial loading on shallow-flaw fracture toughness. Initial emphasis was placed on assessment of stress-based methodologies. namely, the J-Q formulation, the Dodds-Anderson toughness scaling model, and the Weibull approach. Applications of these methodologies based on the hydrostatic stress fracture criterion indicated an effect of loading-biaxiality on fracture toughness, the conventional maximum principal stress criterion indicated no effect

  8. Preliminary assessment of the effects of biaxial loading on reactor pressure vessel structural-integrity-assessment technology

    International Nuclear Information System (INIS)

    Pennell, W.E.; Bass, B.R.; Bryson, J.W.; Dickson, T.L.; McAfee, W.J.; Merkle, J.G.

    1996-01-01

    Effects of biaxial loading on shallow-flaw fracture toughness were studied to determine potential impact on structural integrity assessment of a reactor pressure vessel (RPV) under pressurized thermal shock (PTS) transient loading and pressure-temperature (PT) loading produced by reactor heatup and cooldown transients. Biaxial shallow-flaw fracture-toughness tests results were also used to determine the parameter controlling fracture in the transition temperature range, and to develop a related dual-parameter fracture-toughness correlation. Shallow-flaw and biaxial loading effects were found to reduce the conditional probability of crack initiation by a factor of nine when the shallow-flaw fracture-toughness K Jc data set, with biaxial-loading effects adjustments, was substituted in place of ASME Code K Ic data set in PTS analyses. Biaxial loading was found to reduce the shallow-flaw fracture toughness of RPV steel such that the lower-bound curve was located between ASME K Ic and K IR curves. This is relevant to future development of P-T curve analysis procedures. Fracture in shallow-flaw biaxial samples tested in the lower transition temperature range was shown to be strain controlled. A strain-based dual-parameter fracture-toughness correlation was developed and shown to be capable of predicting the effect of crack-tip constraint on fracture toughness for strain-controlled fracture

  9. Volatile compound profile of sous-vide cooked lamb loins at different temperature-time combinations.

    Science.gov (United States)

    Roldán, Mar; Ruiz, Jorge; Del Pulgar, José Sánchez; Pérez-Palacios, Trinidad; Antequera, Teresa

    2015-02-01

    Lamb loins were subjected to sous-vide cooking at different combinations of temperature (60 and 80°C) and time (6 and 24h) to assess the effect on the volatile compound profile. Major chemical families in cooked samples were aliphatic hydrocarbons and aldehydes. The volatile compound profile in sous-vide cooked lamb loin was affected by the cooking temperature and time. Volatile compounds arising from lipid oxidation presented a high abundance in samples cooked at low or moderate cooking conditions (60°C for 6 and 24h, 80°C for 6h), while a more intense time and temperature combination (80°C for 24h) resulted on a higher concentration of volatile compounds arising from Strecker degradations of amino acids, as 2-methylpropanal and 3-methylbutanal. Therefore, sous-vide cooking at moderately high temperatures for long times would result in the formation of a stronger meaty flavor and roast notes in lamb meat. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Insertion Testing of Polyethylene Glycol Microneedle Array into Cultured Human Skin with Biaxial Tension

    Science.gov (United States)

    Takano, Naoki; Tachikawa, Hiroto; Miyano, Takaya; Nishiyabu, Kazuaki

    Aiming at the practical use of polyethylene glycol (PEG) microneedles for transdermal drug delivery system (DDS), a testing apparatus for their insertion into cultured human skin has been developed. To simulate the variety of conditions of human skin, biaxial tension can be applied to the cultured human skin. An adopted testing scheme to apply and control the biaxial tension is similar to the deep-draw forming technique. An attention was also paid to the short-time setup of small, thin and wet cultured skin. One dimensional array with four needles was inserted and influence of tension was discussed. It was found that tension, deflection of skin during insertion and original curvature of skin are the important parameters for microneedles array design.

  11. Effects of monoclinic symmetry on the properties of biaxial liquid crystals

    Science.gov (United States)

    Solodkov, Nikita V.; Nagaraj, Mamatha; Jones, J. Cliff

    2018-04-01

    Tilted smectic liquid crystal phases such as the smectic-C phase seen in calamitic liquid crystals are usually treated using the assumption of biaxial orthorhombic symmetry. However, the smectic-C phase has monoclinic symmetry, thereby allowing disassociation of the principal optic and dielectric axes based on symmetry and invariance principles. This is demonstrated here by comparing optical and dielectric measurements for two materials with highly first-order direct transitions from nematic to smectic-C phases. The results show a high difference between the orientations of the principal axes sets, which is interpreted as the existence of two distinct cone angles for optical and dielectric frequencies. Both materials exhibit an increasing degree of monoclinic behavior with decreasing temperature. Due to fast switching speeds, ferroelectric smectic-C* materials are important for fast modulators and LCoS devices, where the dielectric biaxiality influences device operation.

  12. Mechanical properties of stanene under uniaxial and biaxial loading: A molecular dynamics study

    Energy Technology Data Exchange (ETDEWEB)

    Mojumder, Satyajit [Department of Mechanical Engineering, Bangladesh University of Engineering and Technology, Dhaka 1000 (Bangladesh); Amin, Abdullah Al [Department of Mechanical and Aerospace Engineering, Case western Reverse University, Cleveland, Ohio 44106 (United States); Islam, Md Mahbubul, E-mail: mmi122@psu.edu [Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

    2015-09-28

    Stanene, a graphene like two dimensional honeycomb structure of tin has attractive features in electronics application. In this study, we performed molecular dynamics simulations using modified embedded atom method potential to investigate mechanical properties of stanene. We studied the effect of temperature and strain rate on mechanical properties of α-stanene for both uniaxial and biaxial loading conditions. Our study suggests that with the increasing temperature, both the fracture strength and strain of the stanene decrease. Uniaxial loading in zigzag direction shows higher fracture strength and strain compared to the armchair direction, while no noticeable variation in the mechanical properties is observed for biaxial loading. We also found at a higher loading rate, material exhibits higher fracture strength and strain. These results will aid further investigation of stanene as a potential nano-electronics substitute.

  13. New classes of bi-axially symmetric solutions to four-dimensional Vasiliev higher spin gravity

    Energy Technology Data Exchange (ETDEWEB)

    Sundell, Per; Yin, Yihao [Departamento de Ciencias Físicas, Universidad Andres Bello,Republica 220, Santiago de Chile (Chile)

    2017-01-11

    We present new infinite-dimensional spaces of bi-axially symmetric asymptotically anti-de Sitter solutions to four-dimensional Vasiliev higher spin gravity, obtained by modifications of the Ansatz used in https://arxiv.org/abs/1107.1217, which gave rise to a Type-D solution space. The current Ansatz is based on internal semigroup algebras (without identity) generated by exponentials formed out of the bi-axial symmetry generators. After having switched on the vacuum gauge function, the resulting generalized Weyl tensor is given by a sum of generalized Petrov type-D tensors that are Kerr-like or 2-brane-like in the asymptotic AdS{sub 4} region, and the twistor space connection is smooth in twistor space over finite regions of spacetime. We provide evidence for that the linearized twistor space connection can be brought to Vasiliev gauge.

  14. Effects of repeated biaxial loads on the creep properties of cardinal ligaments.

    Science.gov (United States)

    Baah-Dwomoh, Adwoa; De Vita, Raffaella

    2017-10-01

    The cardinal ligament (CL) is one of the major pelvic ligaments providing structural support to the vagina/cervix/uterus complex. This ligament has been studied mainly with regards to its important function in the treatment of different diseases such as surgical repair for pelvic organ prolapse and radical hysterectomy for cervical cancer. However, the mechanical properties of the CL have not been fully determined, despite the important in vivo supportive role of this ligament within the pelvic floor. To advance our limited knowledge about the elastic and viscoelastic properties of the CL, we conducted three consecutive planar equi-biaxial tests on CL specimens isolated from swine. Specifically, the CL specimens were divided into three groups: specimens in group 1 (n = 7) were loaded equi-biaxially to 1 N, specimens in group 2 (n = 8) were loaded equi-biaxially to 2N, and specimens in group 3 (n = 7) were loaded equi-biaxially to 3N. In each group, the equi-biaxial loads of 1N, 2N, or 3N were applied and kept constant for 1200s three times. The two axial loading directions were selected to be the main in-vivo loading direction of the CL and the direction that is perpendicular to it. Using the digital image correlation (DIC) method, the in-plane Lagrangian strains in these two loading directions were measured throughout the tests. The results showed that CL was elastically anisotropic, as statistical differences were found between the mean strains along the two axial loading directions for specimens in group 1, 2, or 3 when the equi-biaxial load reached 1N, 2N, or 3N, respectively. For specimens in group 1 and 2, no statistical differences were detected in the mean normalized strains (or, equivalently, the increase in strain over time) between the two axial loading directions for each creep test. For specimens in group 3, some differences were noted but, by the end of the 3rd creep test, there were no statistical differences in the mean normalized strains between

  15. Chaos synchronization in bi-axial magnets modeled by Bloch equation

    International Nuclear Information System (INIS)

    Moukam Kakmeni, F.M.; Nguenang, J.P.; Kofane, T.C.

    2005-10-01

    In this paper, we show that the bi-axial magnetic material modelled by Bloch equation admits chaotic solutions for a certain set of numerical values assigned to the system of parameters and initial conditions. Using the unidirectional linear and nonlinear feedback schemes, we demonstrate that two such systems can be synchronized together. The chaotic synchronization is discussed in the context of complete synchronization which means that the difference of the states of two relevant systems converge to zero. (author)

  16. Mechanical characterisation of porcine rectus sheath under uniaxial and biaxial tension.

    LENUS (Irish Health Repository)

    Lyons, Mathew

    2014-06-03

    Incisional hernia development is a significant complication after laparoscopic abdominal surgery. Intra-abdominal pressure (IAP) is known to initiate the extrusion of intestines through the abdominal wall, but there is limited data on the mechanics of IAP generation and the structural properties of rectus sheath. This paper presents an explanation of the mechanics of IAP development, a study of the uniaxial and biaxial tensile properties of porcine rectus sheath, and a simple computational investigation of the tissue. Analysis using Laplace׳s law showed a circumferential stress in the abdominal wall of approx. 1.1MPa due to an IAP of 11kPa, commonly seen during coughing. Uniaxial and biaxial tensile tests were conducted on samples of porcine rectus sheath to characterise the stress-stretch responses of the tissue. Under uniaxial tension, fibre direction samples failed on average at a stress of 4.5MPa at a stretch of 1.07 while cross-fibre samples failed at a stress of 1.6MPa under a stretch of 1.29. Under equi-biaxial tension, failure occurred at 1.6MPa with the fibre direction stretching to only 1.02 while the cross-fibre direction stretched to 1.13. Uniaxial and biaxial stress-stretch plots are presented allowing detailed modelling of the tissue either in silico or in a surrogate material. An FeBio computational model of the tissue is presented using a combination of an Ogden and an exponential power law model to represent the matrix and fibres respectively. The structural properties of porcine rectus sheath have been characterised and add to the small set of human data in the literature with which it may be possible to develop methods to reduce the incidence of incisional hernia development.

  17. Ab initio study of Co and Ni under uniaxial and biaxial loading and in epitaxial overlayers

    Czech Academy of Sciences Publication Activity Database

    Zelený, Martin; Legut, Dominik; Šob, Mojmír

    2008-01-01

    Roč. 78, č. 22 (2008), 224105/1-224105/11 ISSN 1098-0121 R&D Projects: GA ČR GD106/05/H008; GA AV ČR IAA1041302; GA MŠk OC 147 Institutional research plan: CEZ:AV0Z20410507 Keywords : ab initio calculations * epitaxial overlayers * uniaxial and biaxial loading Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.322, year: 2008

  18. Investigation of in-plane biaxial low cycle fatigued austenitic stainless steel AISI 321. I. Mechanical testing on the planar biaxial load machine

    International Nuclear Information System (INIS)

    Taran, Yu.V.; Balagurov, A.M.; Kuznetsov, A.N.; Schreiber, J.; Bomas, H.; Stoeberl, Ch.; Rathjen, P.; Vorster, W.J.J.; Korsunsky, A.M.

    2007-01-01

    During fatigue loading of structural materials such as stainless steel, changes in the microstructure which affect the mechanical and physical properties occur. Experimental simulation of the loading conditions that induce the changes can be performed by mechanical loading, usually in the form of uniaxial tension-compression cycling. However, real machines and structures are subjected to more complex multiaxial stresses. Fatigue and fracture under multiaxial stresses are one of the most important current topics aimed at ensuring improved reliability of industrial components. The first step towards better understanding of this problem is to subject the materials to biaxial loading. The material examined was low austenitic stainless steel AISI 321 H. A set of the four samples of cruciform geometry was subjected to the biaxial tension-compression fatigue cycling with the frequency of 0.5 Hz at the applied load of 10-17 kN. The samples are intended for the neutron diffraction measurements of the residual stresses and the mechanical characterizations on a dedicated stress-diffractometer

  19. Effect of metal chloride solutions on coloration and biaxial flexural strength of yttria-stabilized zirconia

    Science.gov (United States)

    Oh, Gye-Jeong; Lee, Kwangmin; Lee, Doh-Jae; Lim, Hyun-Pil; Yun, Kwi-Dug; Ban, Jae-Sam; Lee, Kyung-Ku; Fisher, John G.; Park, Sang-Won

    2012-10-01

    The effect of three kinds of transition metal dopants on the color and biaxial flexural strength of zirconia ceramics for dental applications was evaluated. Presintered zirconia discs were colored through immersion in aqueous chromium, molybdenum and vanadium chloride solutions and then sintered at 1450 °C. The color of the doped specimens was measured using a digital spectrophotometer. For biaxial flexural strength measurements, specimens infiltrated with 0.3 wt% of each aqueous chloride solution were used. Uncolored discs were used as a control. Zirconia specimens infiltrated with chromium, molybdenum and vanadium chloride solutions were dark brown, light yellow and dark yellow, respectively. CIE L*, a*, and b* values of all the chromium-doped specimens and the specimens infiltrated with 0.1 wt% molybdenum chloride solution were in the range of values for natural teeth. The biaxial flexural strengths of the three kinds of metal chloride groups were similar to the uncolored group. These results suggest that chromium and molybdenum dopants can be used as colorants to fabricate tooth colored zirconia ceramic restorations.

  20. A novel constrained H2 optimization algorithm for mechatronics design in flexure-linked biaxial gantry.

    Science.gov (United States)

    Ma, Jun; Chen, Si-Lu; Kamaldin, Nazir; Teo, Chek Sing; Tay, Arthur; Mamun, Abdullah Al; Tan, Kok Kiong

    2017-11-01

    The biaxial gantry is widely used in many industrial processes that require high precision Cartesian motion. The conventional rigid-link version suffers from breaking down of joints if any de-synchronization between the two carriages occurs. To prevent above potential risk, a flexure-linked biaxial gantry is designed to allow a small rotation angle of the cross-arm. Nevertheless, the chattering of control signals and inappropriate design of the flexure joint will possibly induce resonant modes of the end-effector. Thus, in this work, the design requirements in terms of tracking accuracy, biaxial synchronization, and resonant mode suppression are achieved by integrated optimization of the stiffness of flexures and PID controller parameters for a class of point-to-point reference trajectories with same dynamics but different steps. From here, an H 2 optimization problem with defined constraints is formulated, and an efficient iterative solver is proposed by hybridizing direct computation of constrained projection gradient and line search of optimal step. Comparative experimental results obtained on the testbed are presented to verify the effectiveness of the proposed method. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  1. Biaxial testing for nuclear grade graphite by ball on three balls assessment

    International Nuclear Information System (INIS)

    Mohd Reusmaazran Yusof; Yusof Abdullah

    2012-01-01

    Nuclear grade (high-purity) graphite for fuel element and moderator material in Advanced Gas Cooling Reactors (AGR) displays large scatter in strength and a non-linear stress-strain response from the damage accumulation. These responses can be characterized as quasi-brittle behaviour. Current assessments of fracture in core graphite components are based on the linear elastic approximation and thus represent a major assumption. The quasi-brittle behaviour gives challenge to assess the real nuclear graphite component. The selected test method would help to bridge the gap between microscale to macro-scale in real reactor component. The small scale tests presented here can contribute some statistical data to manifests the failure in real component. The evaluation and choice of different solution design of biaxial test will be discussed in this paper. The ball on-three ball test method was used for assessment test follows by numerous of analytical method. The results shown that biaxial strength of the EY9 grade graphite depends on the method used for evaluation. Some of the analytical methods use to calculate biaxial strength were found not to be valid and therefore should not be used to assess the mechanical properties of nuclear graphite. (author)

  2. Biaxial thermal creep of Inconel 617 and Haynes 230 at 850 and 950 °C

    International Nuclear Information System (INIS)

    Tung, Hsiao-Ming; Mo, Kun; Stubbins, James F.

    2014-01-01

    The biaxial thermal creep behavior of Inconel 617 and Haynes 230 at 850 and 950 °C was investigated. Biaxial stresses were generated using the pressurized tube technique. The detailed creep deformation and fracture mechanism have been studied. Creep curves for both alloys showed that tertiary creep accounts for a greater portion of the materials’ life, while secondary creep only accounts for a small portion. Fractographic examinations of the two alloys indicated that nucleation, growth, and coalescence of creep voids are the dominant micro-mechanisms for creep fracture. At 850 °C, alloy 230 has better creep resistance than alloy 617. When subjected to the biaxial stress state, the creep rupture life of the two alloys was considerably reduced when compared to the results obtained by uniaxial tensile creep tests. The Monkman–Grant relation proves to be a promising method for estimating the long-term creep life for alloy 617, whereas alloy 230 does not follow the relation. This might be associated with the significant changes in the microstructure of alloy 230 at high temperatures

  3. A study of extracellular matrix remodeling in aortic heart valves using a novel biaxial stretch bioreactor.

    Science.gov (United States)

    Lei, Ying; Masjedi, Shirin; Ferdous, Zannatul

    2017-11-01

    In aortic valves, biaxial cyclic stretch is known to modulate cell differentiation, extracellular matrix (ECM) synthesis and organization. We designed a novel bioreactor that can apply independent and precise stretch along radial and circumferential directions in a tissue culture environment. While this bioreactor can be used for either native or engineered tissues, this study determined matrix remodeling and strain distribution of aortic cusps after culturing under biaxial stretch for 14 days. The contents of collagen and glycosaminoglycans were determined using standard biochemical assays and compared with fresh controls. Strain fields in static cusps were more uniform than those in stretched cusps, which indicated degradation of the ECM fibers. The glycosaminoglycan content was significantly elevated in the static control as compared to fresh or stretched cusps, but no difference was observed in collagen content among the groups. The strain profile of freshly isolated fibrosa vs. ventricularis and left, right, and noncoronary cusps were also determined by Digital Image Correlation technique. Distinct strain patterns were observed under stretch on fibrosa and ventricularis sides and among the three cusps. This work highlights the critical role of the anisotropic ECM structure for proper functions of native aortic valves and the beneficial effects of biaxial stretch for maintenance of the native ECM structure. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Uniaxial and biaxial tensioning effects on thin membrane materials. [large space structures

    Science.gov (United States)

    Hinson, W. F.; Goslee, J. W.

    1980-01-01

    Thin laminated membranes are being considered for various surface applications on future large space structural systems. Some of the thin membranes would be stretched across or between structural members with the requirement that the membrane be maintained within specified limits of smoothness which would be dictated by the particular applications such as antenna reflector requirements. The multiaxial tensile force required to maintain the smoothness in the membrane needs to be determined for use in the structure design. Therefore, several types of thicknesses of thin membrane materials have been subjected to varied levels of uniaxial and biaxial tensile loads. During the biaxial tests, deviations of the material surface smoothness were measured by a noncontacting capacitance probe. Basic materials consisted of composites of vacuum deposited aluminum on Mylar and Kapton ranging in thickness from 0.00025 in (0.000635 cm) to 0.002 in (0.00508 cm). Some of the material was reinforced with Kevlar and Nomex scrim. The uniaxial tests determined the material elongation and tensile forces up to ultimate conditions. Biaxial tests indicated that a relatively smooth material surface could be achieved with tensile force of approximately 1 to 15 Newtons per centimeter, depending upon the material thickness and/or reinforcement.

  5. Microbiological and other characteristics of chicken breast meat following electron-beam and sous-vide treatments

    International Nuclear Information System (INIS)

    Shamsuzzaman, K.; Chuaqui-Offermanns, N.; Lucht, L.; McDougall, T.; Borsa, J.

    1992-01-01

    The combined effects of radiation and sous-vide treatment of chicken breast meat were investigated with respect to survival and growth of Listeria monocytogenes, shelf life, thiamine content, and sensory qualities. Chicken breasts were inoculated with L. monocytogenes 81-861 (10(5) CFU/G), vacuum-packed, irradiated with electron beam (EB) up to 2.9 kGy, and cooked to an internal temperature of 65.6 degrees C. Sous-vide treatment alone had marginal lethal effect on the L. monocytogenes; the residual inoculum reached 10(7) CFU/g after 8 weeks at 2 degrees C. However, after the combined treatments of sous-vide and EB at 2.9 kGy, the organism remained undetectable during the 8-week storage period. Parallel studies on uninoculated breast meat revealed that sous-vide samples had a shelf life of less than 6 weeks without EB treatment, whereas samples that were irradiated and then received sous-vide treatment had a shelf life of at least 8 weeks. There was a slight reduction in thiamine levels as a result of the EB treatment, but there was essentially no additional loss of thiamine due to the subsequent sous-vide treatment and storage at 2 degrees C. Electron-beam treatment had very little effect on the odor and flavor of the reheated samples. It was concluded that EB treatment combined with, sous-vide treatment can greatly enhance the microbial safety and shelf life of chicken breast meat

  6. Study of the effect of an equi-biaxial loading on the fatigue lifetime of austenitic stainless steel

    International Nuclear Information System (INIS)

    Bradai, Soumaya

    2014-01-01

    Fatigue lifetime assessment is essential in the design of structures. Under-estimated predictions may result in unnecessary in service inspections. Conversely, over-estimated predictions may have serious consequences on the integrity of structures.In some nuclear power plant components, the fatigue loading may be equi-biaxial because of thermal fatigue. So the potential impact of multiaxial loading on the fatigue life of components is a major concern. Meanwhile, few experimental data are available on austenitic stainless steels. It is essential to improve the fatigue assessment methodologies to take into account the potential equi-biaxial fatigue damage. Hence this requires obtaining experimental data on the considered material with a strain tensor in equi-biaxial tension. The aim of this study is to present the experimental and numerical results obtained with a device 'FABIME2' developed in the LISN in collaboration with EDF and AREVA. The association of the experimental results, obtained on the new experimental fatigue device FABIME2, with the numerical analyses obtained by FEM simulation with Cast3M code, has enabled to define the aggravating effect of the equi-biaxial fatigue loading. However, this effect is covered by the Design fatigue curve defined from the nuclear industry. For the crack propagation, a first simplified approach enables to study the kinetic behavior of crack propagation in equi-biaxial fatigue. (author) [fr

  7. Thermograms of the combined High Hydrostatic Pressure and Sous-vide treated Longissimus dorsi of pork

    Science.gov (United States)

    Kenesei, Gy; Jónás, G.; Salamon, B.; Dalmadi, I.

    2017-10-01

    In this work, slices of Longissimus dorsi of pork was used as raw material to establish the effects of the sous-vide technology and the high hydrostatic pressure treatments (and their combinations) on meat. The state of the proteins in meat has a very important effect on several quality parameters of the product, such as weight loss, water holding capacity, organoleptic properties. Therefore it is important to follow and analyse the denaturation of the protein content during food processing. The samples were cooked sous-vide (60 °C, 5-480 minutes) or pressurized (100-600 MPa, 5 minutes, room temperature). Also two steps treatments were studied combining both technologies, applying high hydrostatic pressure treatment (300 or 600 MPa, 5 minutes, room temperature) after or previous to sous-vide cooking (60 °C, 30 minutes). The changes in the condition of meat proteins were followed by a differential scanning calorimeter. The DSC curves were analysed using the unit’s own software where denaturation heat was determined. Thermograms show through the change of the sample’s protein state the dissimilar effect of the treatments. Using the Polar Qualification System -previously proved to be effective with NIR measurements- the spectral information was reduced to a two dimensional polar co-ordinate system where each DSC curve is represented by a “quality point”. As a new experiment the applied PQS data reduction method compared to the traditional thermal analysis data processing gave us less information on the differences of our samples although the results are promising as we were able to detect the same trends and characteristics.

  8. Long-time water level observations at the HDR-testsite Soultz-sous-Forets

    Energy Technology Data Exchange (ETDEWEB)

    Dornstaedter, J; Heinemann-Glutsch, B; Zaske, J [GTC-Kappelmeyer GmbH, Karlsruhe (Germany)

    1997-12-01

    Pressure or water level measurements have been performed by GTC in different wells at the geothermal testsite Soultz-sous-Forets for six years now. The water lever variations are mainly influenced by earth tides, barometric pressure variations, hydraulic testing and stimulation. The small scale variations are influenced by tidal and barometric forcing functions, the large scale variations by hydraulic testing and stimulation. By analyzing such measurements it is possible to get important information about the hydrualic connections between the boreholes, as well as aquifer parameters. (orig./AKF)

  9. Leuconostoc rapi sp. nov., isolated from sous-vide cooked rutabaga

    DEFF Research Database (Denmark)

    Lyhs, Ulrike; Snauwaert, I.; Pihlajaviita, S.

    2015-01-01

    A Gram-positive, ovoid lactic acid bacterium, strain LMG 27676T, was isolated from a spoiled sous-vide cooked rutabaga. 16S rRNA gene sequence analysis indicated that the novel strain belongs to the genus Leuconostoc, with Leuconostoc kimchi and Leuconostoc miyukkimchii as nearest neighbours (99.......1 and 98.8% 16S rRNA gene sequence similarity towards the type strain, respectively). Phylogenetic analysis of the 16S rRNA gene, multilocus sequence analysis of the pheS, rpoA and atpA genes, and biochemical and genotypic characteristics allowed to differentiate strain LMG 27676T from all established...

  10. Etude de la propagation sous critique dans les fibres de verre par relaxation de la charge

    OpenAIRE

    R'Mili , M.; Godin , N.; Lamon , J.

    2011-01-01

    International audience; Plusieurs fibres inorganiques de type verre ou céramique (à base de carbure de silicium) sont très sensibles à la propagation sous critique de fissures, activée chimiquement ou thermiquement. Dans ce cas la rupture survient d'une façon prématurée à un niveau de contrainte relativement bas comparé à la contrainte de rupture. Cet article propose une approche statistique de la rupture en fatigue statique fondée sur l'analyse de la rupture des fibres dans une mèche sollici...

  11. Biaxially mechanical tuning of 2-D reversible and irreversible surface topologies through simultaneous and sequential wrinkling.

    Science.gov (United States)

    Yin, Jie; Yagüe, Jose Luis; Boyce, Mary C; Gleason, Karen K

    2014-02-26

    Controlled buckling is a facile means of structuring surfaces. The resulting ordered wrinkling topologies provide surface properties and features desired for multifunctional applications. Here, we study the biaxially dynamic tuning of two-dimensional wrinkled micropatterns under cyclic mechanical stretching/releasing/restretching simultaneously or sequentially. A biaxially prestretched PDMS substrate is coated with a stiff polymer deposited by initiated chemical vapor deposition (iCVD). Applying a mechanical release/restretch cycle in two directions loaded simultaneously or sequentially to the wrinkled system results in a variety of dynamic and tunable wrinkled geometries, the evolution of which is investigated using in situ optical profilometry, numerical simulations, and theoretical modeling. Results show that restretching ordered herringbone micropatterns, created through sequential release of biaxial prestrain, leads to reversible and repeatable surface topography. The initial flat surface and the same wrinkled herringbone pattern are obtained alternatively after cyclic release/restretch processes, owing to the highly ordered structure leaving no avenue for trapping irregular topological regions during cycling as further evidenced by the uniformity of strains distributions and negligible residual strain. Conversely, restretching disordered labyrinth micropatterns created through simultaneous release shows an irreversible surface topology whether after sequential or simultaneous restretching due to creation of irregular surface topologies with regions of highly concentrated strain upon formation of the labyrinth which then lead to residual strains and trapped topologies upon cycling; furthermore, these trapped topologies depend upon the subsequent strain histories as well as the cycle. The disordered labyrinth pattern varies after each cyclic release/restretch process, presenting residual shallow patterns instead of achieving a flat state. The ability to

  12. Biaxial loading and shallow-flaw effects on crack-tip constraint and fracture toughness

    International Nuclear Information System (INIS)

    Bass, B.R.; Bryson, J.W.; Theiss, T.J.; Rao, M.C.

    1994-01-01

    A program to develop and evaluate fracture methodologies for the assessment of crack-tip constraint effects on fracture toughness of reactor pressure vessel (RPV) steels has been initiated in the Heavy-Section Steel Technology (HSST) Program. Crack-tip constraint is an issue that significantly impacts fracture mechanics technologies employed in safety assessment procedures for commercially licensed nuclear RPVs. The focus of studies described herein is on the evaluation of two stressed-based methodologies for quantifying crack-tip constraint (i.e., J-Q theory and a micromechanical scaling model based on critical stressed volumes) through applications to experimental and fractographic data. Data were utilized from single-edge notch bend (SENB) specimens and HSST-developed cruciform beam specimens that were tested in HSST shallow-crack and biaxial testing programs. Results from applications indicate that both the J-Q methodology and the micromechanical scaling model can be used successfully to interpret experimental data from the shallow- and deep-crack SENB specimen tests. When applied to the uniaxially and biaxially loaded cruciform specimens, the two methodologies showed some promising features, but also raised several questions concerning the interpretation of constraint conditions in the specimen based on near-tip stress fields. Fractographic data taken from the fracture surfaces of the SENB and cruciform specimens are used to assess the relevance of stress-based fracture characterizations to conditions at cleavage initiation sites. Unresolved issues identified from these analyses require resolution as part of a validation process for biaxial loading applications. This report is designated as HSST Report No. 142

  13. Regional and depth variability of porcine meniscal mechanical properties through biaxial testing.

    Science.gov (United States)

    Kahlon, A; Hurtig, M B; Gordon, K D

    2015-01-01

    The menisci in the knee joint undergo complex loading in-vivo resulting in a multidirectional stress distribution. Extensive mechanical testing has been conducted to investigate the tissue properties of the knee meniscus, but the testing conditions do not replicate this complex loading regime. Biaxial testing involves loading tissue along two different directions simultaneously, which more accurately simulates physiologic loading conditions. The purpose of this study was to report mechanical properties of meniscal tissue resulting from biaxial testing, while simultaneously investigating regional variations in properties. Ten left, fresh porcine joints were obtained, and the medial and lateral menisci were harvested from each joint (twenty menisci total). Each menisci was divided into an anterior, middle and posterior region; and three slices (femoral, deep and tibial layers) were obtained from each region. Biaxial and constrained uniaxial testing was performed on each specimen, and Young's moduli were calculated from the resulting stress strain curves. Results illustrated significant differences in regional mechanical properties, with the medial anterior (Young's modulus (E)=11.14 ± 1.10 MPa), lateral anterior (E=11.54 ± 1.10 MPa) and lateral posterior (E=9.0 ± 1.2 MPa) regions exhibiting the highest properties compared to the medial central (E=5.0 ± 1.22 MPa), medial posterior (E=4.16 ± 1.13 MPa) and lateral central (E=5.6 ± 1.20 MPa) regions. Differences with depth were also significant on the lateral meniscus, with the femoral (E=12.7 ± 1.22 MPa) and tibial (E=8.6 ± 1.22 MPa) layers exhibiting the highest Young's moduli. This data may form the basis for future modeling of meniscal tissue, or may aid in the design of synthetic replacement alternatives. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Changes provoked by boiling, steaming and sous-vide cooking in the lipid and volatile profile of European sea bass.

    Science.gov (United States)

    Nieva-Echevarría, Bárbara; Manzanos, María J; Goicoechea, Encarnación; Guillén, María D

    2017-09-01

    This study aims to shed light on the changes provoked by boiling, steaming and sous-vide cooking on the lipids and volatile profile of farmed and wild European sea bass meat. None of the cooking techniques provoked changes due to hydrolytic or oxidation processes detectable by 1 H NMR on sea bass lipids. The lipid profile of main and minor lipidic components was maintained after cooking. However, study by SPME-GC/MS evidenced that steaming and sous-vide cooking modified the volatile profile of sea bass meat, especially in farmed specimens. The compounds generated came from the occurrence, to a very small extent, of lipid and protein degradation. By contrast, boiling scarcely modified the initial characteristics of raw sea bass. Thus, from a sensory point of view and considering the odour-active compounds generated, steaming and sous-vide cooking provoked more noticeable changes than boiling, especially in farmed sea bass meat. Copyright © 2017. Published by Elsevier Ltd.

  15. Formation of biaxial texture in metal films by selective ion beam etching

    Energy Technology Data Exchange (ETDEWEB)

    Park, S.J. [Department of Materials Science and Engineering, University of Florida, 106 Rhines Hall, P.O. Box 116400, Gainesville, FL 32611 (United States); Norton, D.P. [Department of Materials Science and Engineering, University of Florida, 106 Rhines Hall, P.O. Box 116400, Gainesville, FL 32611 (United States)]. E-mail: dnort@mse.ufl.edu; Selvamanickam, Venkat [IGC-SuperPower, LLC, 450 Duane Avenue, Schenectady, NY 12304 (United States)

    2006-05-15

    The formation of in-plane texture via ion bombardment of uniaxially textured metal films was investigated. In particular, selective grain Ar ion beam etching of uniaxially textured (0 0 1) Ni was used to achieve in-plane aligned Ni grains. Unlike conventional ion beam assisted deposition, the ion beam irradiates the uniaxially textured film surface with no impinging deposition flux. The initial uniaxial texture is established via surface energy minimization with no ion irradiation. Within this sequential texturing method, in-plane grain alignment is driven by selective etching and grain overgrowth. Biaxial texture was achieved for ion beam irradiation at elevated temperature.

  16. Formation of biaxial texture in metal films by selective ion beam etching

    International Nuclear Information System (INIS)

    Park, S.J.; Norton, D.P.; Selvamanickam, Venkat

    2006-01-01

    The formation of in-plane texture via ion bombardment of uniaxially textured metal films was investigated. In particular, selective grain Ar ion beam etching of uniaxially textured (0 0 1) Ni was used to achieve in-plane aligned Ni grains. Unlike conventional ion beam assisted deposition, the ion beam irradiates the uniaxially textured film surface with no impinging deposition flux. The initial uniaxial texture is established via surface energy minimization with no ion irradiation. Within this sequential texturing method, in-plane grain alignment is driven by selective etching and grain overgrowth. Biaxial texture was achieved for ion beam irradiation at elevated temperature

  17. Biaxially stretchable supercapacitors based on the buckled hybrid fiber electrode array

    Science.gov (United States)

    Zhang, Nan; Zhou, Weiya; Zhang, Qiang; Luan, Pingshan; Cai, Le; Yang, Feng; Zhang, Xiao; Fan, Qingxia; Zhou, Wenbin; Xiao, Zhuojian; Gu, Xiaogang; Chen, Huiliang; Li, Kewei; Xiao, Shiqi; Wang, Yanchun; Liu, Huaping; Xie, Sishen

    2015-07-01

    In order to meet the growing need for smart bionic devices and epidermal electronic systems, biaxial stretchability is essential for energy storage units. Based on porous single-walled carbon nanotube/poly(3,4-ethylenedioxythiophene) (SWCNT/PEDOT) hybrid fiber, we designed and fabricated a biaxially stretchable supercapacitor, which possesses a unique configuration of the parallel buckled hybrid fiber array. Owing to the reticulate SWCNT film and the improved fabrication technique, the hybrid fiber retained its porous architecture both outwardly and inwardly, manifesting a superior capacity of 215 F g-1. H3PO4-polyvinyl alcohol gel with an optimized component ratio was introduced as both binder and stretchable electrolyte, which contributed to the regularity and stability of the buckled fiber array. The buckled structure and the quasi one-dimensional character of the fibers endow the supercapacitor with 100% stretchability along all directions. In addition, the supercapacitor exhibited good transparency, as well as excellent electrochemical properties and stability after being stretched 5000 times.In order to meet the growing need for smart bionic devices and epidermal electronic systems, biaxial stretchability is essential for energy storage units. Based on porous single-walled carbon nanotube/poly(3,4-ethylenedioxythiophene) (SWCNT/PEDOT) hybrid fiber, we designed and fabricated a biaxially stretchable supercapacitor, which possesses a unique configuration of the parallel buckled hybrid fiber array. Owing to the reticulate SWCNT film and the improved fabrication technique, the hybrid fiber retained its porous architecture both outwardly and inwardly, manifesting a superior capacity of 215 F g-1. H3PO4-polyvinyl alcohol gel with an optimized component ratio was introduced as both binder and stretchable electrolyte, which contributed to the regularity and stability of the buckled fiber array. The buckled structure and the quasi one-dimensional character of the

  18. In-situ neutron diffraction study of Zircaloy 4 subjected to biaxial tension

    Energy Technology Data Exchange (ETDEWEB)

    Gharghouri, M.A. [Canadian Neutron Beam Centre, Chalk River Laboratories, Chalk River, ON (Canada); McDonald, D.; Xiao, L. [Atomic Energy of Canada Limited, Chalk River, ON (Canada)

    2014-07-01

    Zircaloy-4 is widely used as fuel element cladding in nuclear reactors. Pellet-clad interaction (PCI) failure is a concern for many water reactor fuel designs. Extensive work on the mechanism of PCI failure has led to the conclusion that stress corrosion cracking (SCC) induced by iodine vapour in the temperature range relevant to fuel operation is the most probable cause of PCI failure in zirconium alloy fuel element cladding. In-situ neutron diffraction measurements performed on tubular Zircaloy-4 specimens simultaneously pulled in tension and pressurized internally will provide information on the effects of stress biaxiality on the distribution of stresses at the crystal level during loading. (author)

  19. Numerical modelling of fracture initiation and propagation in biaxial tests on rock samples

    CSIR Research Space (South Africa)

    Van de Steen, B

    2001-03-01

    Full Text Available and Peirce, 1995). Additional edges can be obtained in the Voronoi tessellation, by connecting the geometric centre of the Voronoi polygons with the vertices of the polygons. These last elements are further referred to as the internal fracture paths, while... samples without flaws therefore display a very brittle behaviour (Napier and Peirce, 1995). To obtain a more plastic behaviour, it may be necessary to adjust the flaw density as well (D0 to D0b, Table 2). The brittleness of the simulated biaxial tests...

  20. SPICE compatible analytical electron mobility model for biaxial strained-Si-MOSFETs

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhry, Amit; Sangwan, S. [UIET, Panjab University, Chandigarh (India); Roy, J. N., E-mail: amit_chaudhry01@yahoo.com [Solar Semiconductro Pvt. Ltd, Hyderabad (India)

    2011-05-15

    This paper describes an analytical model for bulk electron mobility in strained-Si layers as a function of strain. Phonon scattering, columbic scattering and surface roughness scattering are included to analyze the full mobility model. Analytical explicit calculations of all of the parameters to accurately estimate the electron mobility have been made. The results predict an increase in the electron mobility with the application of biaxial strain as also predicted from the basic theory of strain physics of metal oxide semiconductor (MOS) devices. The results have also been compared with numerically reported results and show good agreement. (semiconductor devices)

  1. Magnetic response of FeNbCuBSi RQ ribbons to bi-axial strain

    Energy Technology Data Exchange (ETDEWEB)

    Butvin, P. E-mail: fyzipbut@nic.savba.sk; Butvinova, B.; Frait, Z.; Sitek, J.; Svec, P

    2000-06-02

    Nanocrystalline strip samples of the FeNbCuBSi class that are macroscopically heterogeneous due to surface /volume differences have been investigated. This heterogeneity is found to be a general property of the class. It represents a base for mutual force influence between the surface and the majority volume beneath. The bi-axial in-plane stress exerted by the ribbon surfaces on the volume is demonstrated first of all by a magnetoelastic anisotropy. The contribution of the creep-induced anisotropy, which can build up under the surface stress at post-treatment temperature, is also found possible.

  2. Magnetic response of FeNbCuBSi RQ ribbons to bi-axial strain

    International Nuclear Information System (INIS)

    Butvin, P.; Butvinova, B.; Frait, Z.; Sitek, J.; Svec, P.

    2000-01-01

    Nanocrystalline strip samples of the FeNbCuBSi class that are macroscopically heterogeneous due to surface /volume differences have been investigated. This heterogeneity is found to be a general property of the class. It represents a base for mutual force influence between the surface and the majority volume beneath. The bi-axial in-plane stress exerted by the ribbon surfaces on the volume is demonstrated first of all by a magnetoelastic anisotropy. The contribution of the creep-induced anisotropy, which can build up under the surface stress at post-treatment temperature, is also found possible

  3. Tunnel splitting in biaxial spin models investigated with spin-coherent-state path integrals

    International Nuclear Information System (INIS)

    Chen Zhide; Liang, J.-Q.; Pu, F.-C.

    2003-01-01

    Tunnel splitting in biaxial spin models is investigated with a full evaluation of the fluctuation functional integrals of the Euclidean kernel in the framework of spin-coherent-state path integrals which leads to a magnitude of tunnel splitting quantitatively comparable with the numerical results in terms of diagonalization of the Hamilton operator. An additional factor resulted from a global time transformation converting the position-dependent mass to a constant one seems to be equivalent to the semiclassical correction of the Lagrangian proposed by Enz and Schilling. A long standing question whether the spin-coherent-state representation of path integrals can result in an accurate tunnel splitting is therefore resolved

  4. SPICE compatible analytical electron mobility model for biaxial strained-Si-MOSFETs

    International Nuclear Information System (INIS)

    Chaudhry, Amit; Sangwan, S.; Roy, J. N.

    2011-01-01

    This paper describes an analytical model for bulk electron mobility in strained-Si layers as a function of strain. Phonon scattering, columbic scattering and surface roughness scattering are included to analyze the full mobility model. Analytical explicit calculations of all of the parameters to accurately estimate the electron mobility have been made. The results predict an increase in the electron mobility with the application of biaxial strain as also predicted from the basic theory of strain physics of metal oxide semiconductor (MOS) devices. The results have also been compared with numerically reported results and show good agreement. (semiconductor devices)

  5. A novel biaxial specimen for inducing residual stresses in thermoset polymers and fibre composite material

    DEFF Research Database (Denmark)

    Jakobsen, Johnny; Andreasen, Jens Henrik; Jensen, Martin

    2015-01-01

    engineers when they challenge the material limits in present and future thermoset and composite component. In addition to the new specimen configuration, this paper presents an analytical solution for the residual stress state in the specimen. The analytical solution assumes linear elastic and isotropic......A new type of specimen configuration with the purpose of introducing a well-defined biaxial residual (axisymmetric) stress field in a neat thermoset or a fibre composite material is presented. The ability to experimentally validate residual stress predictions is an increasing need for design...

  6. Biaxial creep deformation of Zircaloy-4 in the high alpha phase temperature range

    International Nuclear Information System (INIS)

    Donaldson, A.T.; Horwood, R.A.; Healey, T.

    1983-01-01

    The ballooning response of Zircaloy-4 fuel tubes during a postulated loss-of-coolant accident may be calculated from a knowledge of the thermal environment of the rods and the creep deformation characteristics of the cladding. In support of such calculations biaxial creep studies have been performed on fuel tubes supplied by Westinghouse, Wolverine and Sandvik of temperatures in the alpha phase range. This paper presents the results of an investigation of their respective creep behaviour which has resulted in the formulation of equations for use in LOCA fuel ballooning codes. (author)

  7. Particle flow of ceramic breeder pebble beds in bi-axial compression experiments

    International Nuclear Information System (INIS)

    Hermsmeyer, S.; Reimann, J.

    2002-01-01

    Pebble beds of ceramic material are investigated within the framework of developing solid breeder blankets for future fusion power plants. A thermo-mechanical characterisation of such pebble beds is mandatory for understanding the behaviour of pebble beds, and thus the overall blanket, under fusion environment conditions. The mechanical behaviour of pebble beds is typically explored with uni-axial, bi-axial and tri-axial compression experiments. The latter two types of experiment are particularly revealing since they contain explicitly, beyond a compression behaviour of the bed, information on the conditions for pebble flow, i.e. macroscopic relocation, in the pebble bed. (orig.)

  8. Evaluation of Anisotropic Biaxial Stress Induced Around Trench Gate of Si Power Transistor Using Water-Immersion Raman Spectroscopy

    Science.gov (United States)

    Suzuki, Takahiro; Yokogawa, Ryo; Oasa, Kohei; Nishiwaki, Tatsuya; Hamamoto, Takeshi; Ogura, Atsushi

    2018-05-01

    The trench gate structure is one of the promising techniques to reduce on-state resistance (R on) for silicon power devices, such as insulated gate bipolar transistors and power metal-oxide-semiconductor field-effect transistors. In addition, it has been reported that stress is induced around the trench gate area, modifying the carrier mobilities. We evaluated the one-dimensional distribution and anisotropic biaxial stress by quasi-line excitation and water-immersion Raman spectroscopy, respectively. The results clearly confirmed anisotropic biaxial stress in state-of-the-art silicon power devices. It is theoretically possible to estimate carrier mobility using piezoresistance coefficients and anisotropic biaxial stress. The electron mobility was increased while the hole mobility was decreased or remained almost unchanged in the silicon (Si) power device. The stress significantly modifies the R on of silicon power transistors. Therefore, their performance can be improved using the stress around the trench gate.

  9. Biaxial direct tensile tests in a large range of strain rates. Results on a ferritic nuclear steel

    Energy Technology Data Exchange (ETDEWEB)

    Albertini, C.; Labibes, K.; Montagnani, M.; Pizzinato, E.V.; Solomos, G.; Viaccoz, B. [Commission of the European Communities, Ispra (Italy). Joint Research Centre

    2000-09-01

    Constitutive equations are usually calibrated only trough the experimental results obtained by means of unixial tests because of the lack of adequate biaxial experimental data especially at high strain rate conditions. These data are however important for the validation of analytical models and also for the predictions of mechanical behaviour of real structures subjected to multiaxial loading by numerical simulations. In this paper some developments are shown concerning biaxial cruciform specimens and different experimental machines allowing biaxial tests in a large range of strain rates. This experimental campaign has also allowed study of the influence of changing the strain paths. Diagrams of equivalent stress versus straining direction and also equivalent plastic fracture strain versus straining direction are shown. (orig.)

  10. Les effets potentiels du taping chez une population adulte souffrant d'un conflit sous-acromial

    OpenAIRE

    Roch, Sylvie; Thétaz, Alain; Balthazard, Pierre

    2012-01-01

    Introduction : Le conflit sous-acromial est une pathologie fréquente qui touche une grande partie de la population. Quelques revues de la littérature recommandent une prise en charge spécifique, mais peu d’études proposent le taping comme adjuvant aux traitements préconisés. Ainsi ce travail de bachelor a pour objectif de déterminer les effets potentiels du taping chez une population adulte souffrant de conflit sous-acromial. Méthodologie : Notre recherche d’études s’est effectuée de janvier ...

  11. Vacuum brazing of metals (1961); Brassure sous vide des metaux (1961)

    Energy Technology Data Exchange (ETDEWEB)

    Lapujoulade, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1961-07-01

    We have studied brazing in vacuum aiming its application for the making of containers and apparatus meant for high vacuum (p < 10{sup -8} torr). We first define the wettability of a brazing alloy on a metal and we remind the influence of the various parameters which act on this wettability (nature of the solid, of the liquid, geometrical and physicochemical state of the surface, metallurgical reactions occurring at the interface, temperature, time). We give then the results of the tests carried out in order to determine the conditions of wettability in vacuum of some brazing alloys on metals which can be used for the above mentioned apparatus (stainless steel, aluminium, bronze, titanium, zirconium, kovar, nickel, copper). (author) [French] Nous avons etudie la brasure sous vide en vue de son application a la construction d'enceintes et apparelilage destines a l'obtention des vides eleves (p < 10{sup -8} torr). Nous definissons d'abord la mouillabilite d'une brasure sur un metal et nous rappelons l'influence des differents parametres qui agissent sur cette mouillabilite (nature du solide, du liquide, etat geometrique et physico-chimique de la surface, reactions metallurgiques a l'interface, temperature, temps). Nous donnons ensuite les resultats des essais effectues dans le but de determiner les conditions de mouillabilite sous vide de certaines brassures sur des metaux utilisables dans les constructions mentionnees ci-dessus (acier inoxydable, bronze d'aluminium, titane, zirconium, kovar, nickel, cuivre). (auteur)

  12. Experiment to measure the effects of biaxial strain on the critical current of NbTi superconductor

    International Nuclear Information System (INIS)

    Froelich, K.J.

    1975-01-01

    Twisted multifilament, copper-clad NbTi superconductors have been axially and biaxially strained at 4.2K with a 7.5T background field. A simply-constructed cryogenic loading frame was built and used to strain the conductor. Results on 1.27 mm x 3.13 mm conductor have shown that degradation of less than .3 percent of critical current occurred when the wire was biaxially strained to +3260 μepsilon in the axial direction and -1875 μepsilon in the transverse direction. Degradation approaches 3 percent of critical current at approximately 6000 μepsilon in the axial direction only

  13. Bi-axially crumpled silver thin-film electrodes for dielectric elastomer actuators

    International Nuclear Information System (INIS)

    Low, Sze-Hsien; Lau, Gih-Keong

    2014-01-01

    Metal thin films, which have high conductivity, are much stiffer and may fracture at a much lower strain than dielectric elastomers. In order to fabricate compliant electrodes for use in dielectric elastomer actuators (DEAs), metal thin films have been formed into either zigzag patterns or corrugations, which favour bending and only allow uniaxial DEA deformations. However, biaxially compliant electrodes are desired in order to maximize generated forces of DEA. In this paper, we present crumpled metal thin-film electrodes that are biaxially compliant and have full area coverage over the dielectric elastomer. These crumpled metal thin-film electrodes are more stretchable than flat metal thin films; they remain conductive beyond 110% radial strain. Also, crumpling reduced the stiffening effect of metal thin films on the soft elastomer. As such, DEAs using crumpled metal thin-film electrodes managed to attain relatively high actuated area strains of up to 128% at 1.8 kV (102 Vμm −1 ). (paper)

  14. Biaxial-Type Concentrated Solar Tracking System with a Fresnel Lens for Solar-Thermal Applications

    Directory of Open Access Journals (Sweden)

    Tsung Chieh Cheng

    2016-04-01

    Full Text Available In this paper, an electromechanical, biaxial-type concentrated solar tracking system was designed for solar-thermal applications. In our tracking system, the sunlight was concentrated by the microstructure of Fresnel lens to the heating head of the Stirling engine and two solar cells were installed to provide the power for tracking system operation. In order to obtain the maximum sun power, the tracking system traces the sun with the altitude-azimuth biaxial tracing method and accurately maintains the sun’s radiation perpendicular to the plane of the heating head. The results indicated that the position of heating head is an important factor for power collection. If the sunlight can be concentrated to completely cover the heating head with small heat loss, we can obtain the maximum temperature of the heating head of the Stirling engine. Therefore, the temperature of heating head can be higher than 1000 °C in our experiment on a sunny day. Moreover, the results also revealed that the temperature decrease of the heating head is less than the power decrease of solar irradiation because of the latent heat of copper and the small heat loss from the heating head.

  15. Laser damage metrology in biaxial nonlinear crystals using different test beams

    Science.gov (United States)

    Hildenbrand, Anne; Wagner, Frank R.; Akhouayri, Hassan; Natoli, Jean-Yves; Commandre, Mireille

    2008-01-01

    Laser damage measurements in nonlinear optical crystals, in particular in biaxial crystals, may be influenced by several effects proper to these materials or greatly enhanced in these materials. Before discussion of these effects, we address the topic of error bar determination for probability measurements. Error bars for the damage probabilities are important because nonlinear crystals are often small and expensive, thus only few sites are used for a single damage probability measurement. We present the mathematical basics and a flow diagram for the numerical calculation of error bars for probability measurements that correspond to a chosen confidence level. Effects that possibly modify the maximum intensity in a biaxial nonlinear crystal are: focusing aberration, walk-off and self-focusing. Depending on focusing conditions, propagation direction, polarization of the light and the position of the focus point in the crystal, strong aberrations may change the beam profile and drastically decrease the maximum intensity in the crystal. A correction factor for this effect is proposed, but quantitative corrections are not possible without taking into account the experimental beam profile after the focusing lens. The characteristics of walk-off and self-focusing have quickly been reviewed for the sake of completeness of this article. Finally, parasitic second harmonic generation may influence the laser damage behavior of crystals. The important point for laser damage measurements is that the amount of externally observed SHG after the crystal does not correspond to the maximum amount of second harmonic light inside the crystal.

  16. Equi-biaxial loading effect on austenitic stainless steel fatigue life

    Directory of Open Access Journals (Sweden)

    C. Gourdin

    2016-10-01

    Full Text Available Fatigue lifetime assessment is essential in the design of structures. Under-estimated predictions may result in unnecessary in service inspections. Conversely, over-estimated predictions may have serious consequences on the integrity of structures. In some nuclear power plant components, the fatigue loading may be equibiaxial because of thermal fatigue. So the potential impact of multiaxial loading on the fatigue life of components is a major concern. Meanwhile, few experimental data are available on austenitic stainless steels. It is essential to improve the fatigue assessment methodologies to take into account the potential equi-biaxial fatigue damage. Hence this requires obtaining experimental data on the considered material with a strain tensor in equibiaxial tension. Two calibration tests (with strain gauges and image correlation were used to obtain the relationship between the imposed deflection and the radial strain on the FABIME2 specimen. A numerical study has confirmed this relationship. Biaxial fatigue tests are carried out on two austenitic stainless steels for different values of the maximum deflection, and with a load ratio equal to -1. The interpretation of the experimental results requires the use of an appropriate definition of strain equivalent. In nuclear industry, two kinds of definition are used: von Mises and TRESCA strain equivalent. These results have permitted to estimate the impact of the equibiaxiality on the fatigue life of components

  17. Biaxial fatigue tests and crack paths for AISI 304L stainless steel

    Directory of Open Access Journals (Sweden)

    V. Chaves

    2014-10-01

    Full Text Available AISI 304L stainless steel specimens have been tested in fatigue. The tests were axial, torsional and in-phase biaxial, all of them under load control and R=-1. The S-N curves were built following the ASTM E739 standard and the method of maximum likelihood proposed by Bettinelli. The fatigue limits of the biaxial tests were represented in axes σ-τ. The elliptical quadrant, appropriate for ductile materials, and the elliptical arc, appropriate for fragile materials, were included in the graph. The experimental values were better fitted with an elliptical quadrant, despite the ratio between the pure torsion and tension fatigue limits, τFL/σFL, is 0.91, close to 1, which is a typical value for fragile materials. The crack direction along the surface has been analyzed by using a microscope, with especial attention to the crack initiation zones. The crack direction during the Stage I has been compared with theoretical models.

  18. Experimental study of internal conical refraction in a biaxial crystal with Laguerre–Gauss light beams

    International Nuclear Information System (INIS)

    Peet, V

    2014-01-01

    The effect of internal conical refraction (CR) in a biaxial crystal was studied using Laguerre–Gauss light beams LG 0 ℓ with ℓ=1 and 2, while the lowest-order LG 0 0 beam was used as a reference. The transition from ordinary double refraction to CR was examined. It has been shown that double refraction of an LG 0 ℓ beam forms two focal spots containing ℓ dark stripes. These stripes evolve into ℓ+1 dark rings over an annular focal image when CR is established, and it results in a fine-structure of ℓ+2 bright focal rings with different intensities. In a sharp contrast to the lowest-order reference, the multiring focal structure has a distinct asymmetry with respect to the focal image plane. It has been shown that bright off-axis ‘hot spot’ can be formed on the far-field profiles of outgoing light beams when the biaxial crystal is slightly tilted, and a small angle between the propagation axis of the beam and the optic axis of the crystal arises. These off-axis light structures emerge as either a charge-one optical vortex or a zero-charge spot with annihilated vorticity. Polarization selection reveals J 1 or J 0 Bessel-like profiles of the corresponding ‘hot spots’, and a complex pattern of forked fringes in the dark region near the beam core. (paper)

  19. Robust control for a biaxial servo with time delay system based on adaptive tuning technique.

    Science.gov (United States)

    Chen, Tien-Chi; Yu, Chih-Hsien

    2009-07-01

    A robust control method for synchronizing a biaxial servo system motion is proposed in this paper. A new network based cross-coupled control and adaptive tuning techniques are used together to cancel out the skew error. The conventional fixed gain PID cross-coupled controller (CCC) is replaced with the adaptive cross-coupled controller (ACCC) in the proposed control scheme to maintain biaxial servo system synchronization motion. Adaptive-tuning PID (APID) position and velocity controllers provide the necessary control actions to maintain synchronization while following a variable command trajectory. A delay-time compensator (DTC) with an adaptive controller was augmented to set the time delay element, effectively moving it outside the closed loop, enhancing the stability of the robust controlled system. This scheme provides strong robustness with respect to uncertain dynamics and disturbances. The simulation and experimental results reveal that the proposed control structure adapts to a wide range of operating conditions and provides promising results under parameter variations and load changes.

  20. Characterization of mechanical properties of pericardium tissue using planar biaxial tension and flexural deformation.

    Science.gov (United States)

    Murdock, Kyle; Martin, Caitlin; Sun, Wei

    2018-01-01

    Flexure is an important mode of deformation for native and bioprosthetic heart valves. However, mechanical characterization of bioprosthetic leaflet materials has been done primarily through planar tensile testing. In this study, an integrated experimental and computational cantilever beam bending test was performed to characterize the flexural properties of glutaraldehyde-treated bovine and porcine pericardium of different thicknesses. A strain-invariant based structural constitutive model was used to model the pericardial mechanical behavior quantified through the bending tests of this study and the planar biaxial tests previously performed. The model parameters were optimized through an inverse finite element (FE) procedure in order to describe both sets of experimental data. The optimized material properties were implemented in FE simulations of transcatheter aortic valve (TAV) deformation. It was observed that porcine pericardium TAV leaflets experienced significantly more flexure than bovine when subjected to opening pressurization, and that the flexure may be overestimated using a constitutive model derived from purely planar tensile experimental data. Thus, modeling of a combination of flexural and biaxial tensile testing data may be necessary to more accurately describe the mechanical properties of pericardium, and to computationally investigate bioprosthetic leaflet function and design. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Dependence of the optical conductivity on the uniaxial and biaxial strains in black phosphorene

    Science.gov (United States)

    Yang, C. H.; Zhang, J. Y.; Wang, G. X.; Zhang, C.

    2018-06-01

    By using the Kubo formula, the optical conductivity of strained black phosphorene was studied. The anisotropic band dispersion gives rise to an orientation dependent optical conductivity. The energy gap can be tuned by the uniaxial and biaxial strains which can be observed from the interband optical conductivity polarized along the armchair (x ) direction. The preferential conducting direction is along the x direction. The dependence of the intraband optical conductivity along the zigzag (y ) direction on the Fermi energy and strain exhibits increasing or decreasing monotonously. However, along the x direction this dependence is complicated which originates from the carriers' inverse-direction movements obtained by two types of the nearest phosphorus atom interactions. The modification of the biaxial strain on the energy structure and optical-absorption property is more effective. The imaginary part of the total optical conductivity (Im σ ) can be negative around the threshold of the interband optical transition by modifying the chemical potential. Away from this frequency region, Im σ exhibits positive value. It can be used in the application of the surface plasmon propagations in multilayer dielectric structures.

  2. Upregulation of matrix synthesis in chondrocyte-seeded agarose following sustained bi-axial cyclic loading

    Directory of Open Access Journals (Sweden)

    Belinda Pingguan-Murphy

    2012-08-01

    Full Text Available OBJECTIVES: The promotion of extracellular matrix synthesis by chondrocytes is a requisite part of an effective cartilage tissue engineering strategy. The aim of this in vitro study was to determine the effect of bi-axial cyclic mechanical loading on cell proliferation and the synthesis of glycosaminoglycans by chondrocytes in threedimensional cultures. METHOD: A strain comprising 10% direct compression and 1% compressive shear was applied to bovine chondrocytes seeded in an agarose gel during two 12-hour conditioning periods separated by a 12-hour resting period. RESULTS: The bi-axial-loaded chondrocytes demonstrated a significant increase in glycosaminoglycan synthesis compared with samples exposed to uni-axial or no loading over the same period (p<0.05. The use of a free-swelling recovery period prior to the loading regime resulted in additional glycosaminoglycan production and a significant increase in DNA content (p<0.05, indicating cell proliferation. CONCLUSIONS: These results demonstrate that the use of a bi-axial loading regime results in increased matrix production compared with uni-axial loading.

  3. Thermal and radiation induced polymerisation of carbon sub-oxide; Polymerisation thermique et sous rayonnement du sous-oxyde de carbone

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Michel

    1964-03-15

    This research thesis addresses the study of the polymerisation of carbon sub-oxide (C{sub 3}O{sub 2}) in gaseous phase. As this work is related to other researches dealing with the reactions of the graphite-CO{sub 2} system which occur in graphite-moderated nuclear reactors, a first intention was to study the behaviour of C{sub 3}O{sub 2} when submitted to radiations. Preliminary tests showed that the most remarkable result of this action was the formation of a polymer. It was also noticed that the polymerisation of this gas was spontaneous however slower at room temperature. The research thus focused on this polymerisation, and on the formula of the obtained polymer. After some generalities, the author reports the preparation, purification and storage and conservation of the carbon sub-oxide. The next parts report the kinetic study of thermal polymerisation, the study of polymerisation under γ rays, the study of the obtained polymer by using visible, UV and infrared spectroscopy, electronic paramagnetic resonance, and semi-conductivity measurements [French] Le but de ce travail est l'etude de la polymerisation du sous-oxyde de carbone, C{sub 3}O{sub 2}, en phase gazeuse. Ce travail est en relation avec d'autres recherches concernant les reactions du systeme graphite-CO{sub 2} qui se produisent dans les reacteurs nucleaires de la filiere moderee au graphite. Notre premiere intention etait donc d'etudier le comportement de C{sub 3}O{sub 2} sous l'action des rayonnements. Or des essais preliminaires nous ont rapidement montre que le resultat le plus marquant de cette action etait l'obtention d'un polymere. On a egalement remarque que ce gaz polymerisait spontanement - quoique moins rapidement - a la temperature ambiante. Notre etude s'est donc circonscrite a cette polymerisation, avec ou sans rayonnements, ainsi qu'a son aboutissement: le polymere, dont nous avons tente d'eclaircir la formule. Au terme de cette etude, bien que certains points ne soient pas encore

  4. Effect of sous vide processing on physicochemical, ultrastructural, microbial and sensory changes in vacuum packaged chicken sausages.

    Science.gov (United States)

    Naveena, B M; Khansole, Panjab S; Shashi Kumar, M; Krishnaiah, N; Kulkarni, Vinayak V; Deepak, S J

    2017-01-01

    The processing of sous vide chicken sausages was optimized under vacuum packaging condition and cooking at 100 ℃ for 30 min (SV30), 60 min (SV60) and 120 min (SV120) and compared with aerobically cooked control at 100 ℃ for 30 min. Sous vide processing of chicken sausages (SV30) produced higher (p emulsion ultra-structure due to SV30 processing relative to control sausages. Sous vide processing of chicken sausages enriched with rosemary diterpene phenols retained the freshness and quality up to 120 days during storage at 4 ± 1 ℃ relative to control sausages that were spoiled on 20th day. Lipid oxidation and microbial growth remained below the spoilage levels for all the SV-processed sausages throughout the storage and addition of rosemary diterpene mixture at 0.02% v/w reduced the microbial growth and improved (p < 0.05) the sensory attributes. Our results demonstrate that sous vide processing minimizes lipid oxidation and microbial growth of chicken sausages with improved product quality and shelf-life at 4 ± 1 ℃. © The Author(s) 2016.

  5. Biaxial creep deformation of Zircaloy-4 PWR fuel cladding in the alpha,(alpha + beta) and beta phase temperature ranges

    International Nuclear Information System (INIS)

    Donaldson, A.T.; Healey, T.; Horwood, R.A.L.

    1985-01-01

    The biaxial creep behaviour of Zircaloy-4 fuel cladding has been determined at temperatures between 973 - 1073 K in the alpha phase range, in the duplex (alpha + beta) region between 1098 - 1223 K and in the beta phase range between 1323 - 1473 K. This paper presents the creep data together with empirical equations which describe the creep deformation response within each phase region. (author)

  6. Active-flux based motion sensorless vector control of biaxial excitation generator/motor for automobiles (BEGA)

    DEFF Research Database (Denmark)

    Coroban-Schramel, Vasile; Boldea, Ion; Andreescu, Gheorghe-Daniel

    2009-01-01

    This paper proposes a novel, active-flux based, motion-sensorless vector control structure for biaxial excitation generator for automobiles (BEGA) for wide speed range operation. BEGA is a hybrid excited synchronous machine having permanent magnets on q-axis and a dc excitation on daxis. Using th...... electrical degrees in less than 2 ms test time....

  7. Mechanical response of cross-ply Si3N4/BN fibrous monoliths under uniaxial and biaxial loading

    International Nuclear Information System (INIS)

    Singh, D.; Cruse, T. A.; Hermanson, D. J.; Goretta, K. C.; Zok, F. W.; McNulty, J. C.

    2000-01-01

    Mechanical properties of hot-pressed Si 3 N 4 /BN fibrous monoliths (FMs) were evaluated under ambient conditions in four-point and biaxial flexure modes. Effects of cell orientation, 0degree/90degree and ±45degree, on elastic modulus and fracture strength of the FMs were investigated. Fracture surfaces were examined by scanning electron microscopy

  8. Meso-Scale Finite Element Analysis of Mechanical Behavior of 3D Braided Composites Subjected to Biaxial Tension Loadings

    Science.gov (United States)

    Zhang, Chao; Curiel-Sosa, Jose L.; Bui, Tinh Quoc

    2018-04-01

    In many engineering applications, 3D braided composites are designed for primary loading-bearing structures, and they are frequently subjected to multi-axial loading conditions during service. In this paper, a unit-cell based finite element model is developed for assessment of mechanical behavior of 3D braided composites under different biaxial tension loadings. To predict the damage initiation and evolution of braiding yarns and matrix in the unit-cell, we thus propose an anisotropic damage model based on Murakami damage theory in conjunction with Hashin failure criteria and maximum stress criteria. To attain exact stress ratio, force loading mode of periodic boundary conditions which never been attempted before is first executed to the unit-cell model to apply the biaxial tension loadings. The biaxial mechanical behaviors, such as the stress distribution, tensile modulus and tensile strength are analyzed and discussed. The damage development of 3D braided composites under typical biaxial tension loadings is simulated and the damage mechanisms are revealed in the simulation process. The present study generally provides a new reference to the meso-scale finite element analysis (FEA) of multi-axial mechanical behavior of other textile composites.

  9. Effective X-ray elastic constant measurement for in situ stress measurement of biaxially strained AA5754-O

    International Nuclear Information System (INIS)

    Iadicola, Mark A.; Gnäupel-Herold, Thomas H.

    2012-01-01

    Accurate measurement of stresses by X-ray diffraction requires accurate X-ray elastic constants. Calibration experiments are one method to determine these for a specific material in a specific condition. In this paper, uniaxial tension experiments are used to investigate the variation of these constants after uniaxial and equal-biaxial plastic deformation for an aluminum alloy (AA5754-O) of interest to the automotive industry. These data are critical for accurate measurement of the biaxial mechanical properties of the material using a recent experimental method combining specialized sheet metal forming equipment with portable X-ray diffraction equipment. The measured effective X-ray elastic constants show some minor variation with increased plastic deformation, and this behavior was found to be consistent for both uniaxially and equal-biaxially strained samples. The use of two average values for effective X-ray elastic constants, one in the rolling direction and one transverse to the rolling direction of the sheet material, is shown to be of sufficient accuracy for the combined tests of interest. Comparison of uniaxial data measured using X-ray diffraction and standard methods show good agreement, and biaxial stress–strain results show good repeatability. Additionally, the calibration data show some non-linear behavior, which is analyzed in regards to crystallographic texture and intergranular stress effects. The non-linear behavior is found to be the result of intergranular stresses based on comparison with additional measurements using other X-ray diffraction equipment and neutron diffraction.

  10. Guide pour la rédaction de cahiers des charges pour la sous-traitance en mécano-soudage

    CERN Document Server

    Cheminat, Olivier

    2016-01-01

    Ce rapport est principalement dédié aux rédacteurs de cahiers des charges lors de sous-traitance en soudage. Le choix de faire sous-traiter une fabrication et le choix du sous-traitant revêtent une triple dimension technique, économique et stratégique. Un sous-traitant n'est pas un simple fournisseur ; il est un véritable partenaire technique pour le donneur d'ordre qui lui confie la réalisation d'un produit qu'il a lui-même conçu. La sous-traitance nécessite alors, outre un audit préalable du partenaire, un suivi en continu, à distance, et une communication entre le donneur d'ordre et le sous-traitant. Le cahier des charges est un des éléments de cette communication. C'est un outil essentiel, notamment lorsque le marché est soumis à des normes, imposées par contrat entre le donneur d'ordre et le sous-traitant. Ce présent document est un guide pour la rédaction du document de consultation, afin d'être le plus précis et exhaustif possible, mais il ne saurait être utilisé pour établi...

  11. Registration of vehicles at the Gex sous-préfecture: now by appointment only

    CERN Multimedia

    2016-01-01

    The Gex sous-préfecture has informed CERN that it has taken the following steps in order to reduce waiting times at its counters for the issue of carte grise vehicle registration certificates. As of 1 February 2016, you must book an appointment via the website http://www.rdv.ain.gouv.fr/ for all services relating to the registration of vehicles, in particular the:   change of the holder of a registration certificate, issue of a certificat de situation administrative (administrative status certificate required for the sale of a vehicle), change of marital status (or company name in the case of legal entities), change of address, change in the technical specification of the vehicle, corrections to registration certificates, equests for duplicates (loss or theft of registration certificates), registration of a diplomatic vehicle (CERN), registration of a new vehicle, registration of vehicles purchased tax-free in the Pays de Gex free zone (formerly TTW series), and import of vehicles (from ...

  12. Patrimonialiser les bases de sous-marins et le Mur de l’Atlantique

    OpenAIRE

    Prelorenzo, Claude

    2014-01-01

    Le Mur de l’Atlantique court de la frontière espagnole jusqu’au nord de la Norvège. Au sein de ce dispositif sont installées cinq bases de sous-marins : Dunkerque, Saint-Nazaire, Lorient, La Rochelle et Bordeaux. Après une période de purgatoire, liée aux souvenirs trop frais des bombardements qu’ils ont attirés sur les villes, les édifices du mur sont entrés dans la sphère de la culture et du tourisme. Nous posons alors la question suivante : de quoi ces édifices portent-ils témoignage, et no...

  13. Raconter l’Histoire (sous la direction de Prstojevic A.

    Directory of Open Access Journals (Sweden)

    Sophie Thiriar

    2011-10-01

    Full Text Available Sous le titre Raconter l’Histoire, Alexandre Prstojevic a réuni treize articles, faisant suite à deux colloques qui ont eu lieu à Paris en mai 2006 et à Montréal en octobre de la même année. Treize pointures du monde slave se sont intéressées pour l’occasion à la représentation littéraire et cinématographique de l’histoire – principalement celle de l’Europe centrale et orientale – après le spectacle mortifère des deux guerres mondiales. Suite aux multiples expériences déshumanisantes dont est...

  14. Scintigraphy of the Pericerebral Subarachnoidspaces; Scintigraphie des Espaces Sous-Arachnoidiens Pericerebraux

    Energy Technology Data Exchange (ETDEWEB)

    Oberson, R.; Martini, T. [Institut Universitaire de Radiologie Medicale, Hopital Cantonal, Lausanne (Switzerland)

    1969-05-15

    -auricular shunt of the C.S.F. in cases of symptomatic hydrocephalus of traumatic or occult origin in adult or child patients. The study was based on an analysis of over 100 scintigrams of the pericerebral subarachnoid cavities. From this, the authors were gradually able to work out the normal and pathological symptomatology of this field, from the point of view of both cisternal morphology and fluid hydrodynamics. (author) [French] L'exploration des espaces sous-arachnoiediens pericerebraux par les radioisotopes (cisternographie radioisotopique ou 'RISA- cisternography' ) prend une place de plus en plus importante parmi les techniques neuroradioisotopiques de diagnostic. Elle fournit de precieux renseignements sur la permeabilite des espaces sous-arachnoiediens et sur la dynamique du liquide cephalo-rachidien (LCR). On doit actuellement la considerer comme indispensable et irremplacable dans le diagnostic de certaines affections neurologiques, tout comme la gamma-encephalographie et les techniques neuroradiologiques plus classiques (angiographie et pneumographie cerebrales). En effet, cet examen est seul a preciser l'aspect morphologique global des espaces sous-arachnoiediens pericerebraux; tout en renseignant sur la permeabilite des citernes pericerebrales et des sillons de la convexite, il fournit une image scintigraphique typique et symetrique, facile a observer, de face et de profil, des voies principales de circulation du LCR cisternal. L'image scintigraphique d'une citerne indique qu'elle est permeable et que l'espace sous-jacent l'est aussi. Du point de vue dynamique, la cisternographie radioisotopique, outre la demonstration par voie scintigraphique de la permeabilite des citernes, met en evidence le schema normal ou pathologique de la dynamique du LCR. Le schema normal de progression du LCR est actuellement bien etabli. Il est du plus haut interet de le connaitre afin de distinguer deja quelques syndromes pathologiques: la presence d'une fistule de LCR (la

  15. Numerical and experimental analysis of the directional stability on crack propagation under biaxial stresses

    International Nuclear Information System (INIS)

    RodrIguez-MartInez, R; Urriolagoitia-Calderon, G; Urriolagoitia-Sosa, G; Hernandez-Gomez, L H; Merchan-Cruz, E A; RodrIguez-Canizo, R G; Sandoval-Pineda, J M

    2009-01-01

    In this paper, the case of Single Edge Notch (SEN) specimens subject to opening/compressive loading was analyzed; The loads are applied in several ratios to evaluate the influence of the specimen geometry, and the Stress Intensity Factor (SIF) K 1 values on the directional stability of crack propagation. The main purpose of this work is to evaluate the behaviour of the fracture propagation, when modifying the geometry of the SEN specimen and different relationships of load tension/compression are applied. Additionally, the precision of the numerical and experimental analysis is evaluated to determine its reliability when solving this type of problems. The specimens are subjected to biaxial opening/compression loading; both results (numerical and experimental) are compared in order to evaluate the condition of directional stability on crack propagation. Finally, an apparent transition point related to the length of specimens was identified, in which the behaviour of values of SIF changes for different loading ratios.

  16. Fatigue and creep-fatigue strength of 304 steel under biaxial strain conditions

    International Nuclear Information System (INIS)

    Asayama, Tai; Aoto, Kazumi; Wada, Yusaku

    1990-01-01

    A series of fatigue and creep-fatigue tests were conducted with 304 stainless steel at 550degC under a variety of biaxial strain conditions. Fatigue life under nonproportional loading conditions showed a significant life reduction compared with that of proportional loading, and this life reduction was reasonably estimated by taking into account the strain paths along which the strain history is imposed. Furthermore, a marked life reduction was shown to occur under nonproportional loading by imposing a strain hold period at a peak tensile strain. This life reduction was evaluated by the linear damage rule. It was shown to be possible to estimate the fatigue damage and the creep damage under nonproportional loading by a linear damage rule by estimating a stress relaxation behavior by Mises-type equivalent stress or Huddleston-type equivalent stress. (author)

  17. Numerical and experimental analysis of the directional stability on crack propagation under biaxial stresses

    Energy Technology Data Exchange (ETDEWEB)

    RodrIguez-MartInez, R; Urriolagoitia-Calderon, G; Urriolagoitia-Sosa, G; Hernandez-Gomez, L H [Instituto Politecnico Nacional Seccion de Estudios de Posgrado e Investigacion (SEPI), Escuela Superior de IngenierIa Mecanica y Electrica (ESIME), Edificio 5. 2do Piso, Unidad Profesional Adolfo Lopez Mateos ' Zacatenco' Col. Lindavista, C.P. 07738, Mexico, D.F. (Mexico); Merchan-Cruz, E A; RodrIguez-Canizo, R G; Sandoval-Pineda, J M, E-mail: rrodriguezm@ipn.m, E-mail: urrio332@hotmail.co, E-mail: guiurri@hotmail.co, E-mail: luishector56@hotmail.co, E-mail: eamerchan@gmail.co, E-mail: ricname@hotmail.co, E-mail: jsandovalp@ipn.m [Instituto Politecnico Nacional Seccion de Estudios de Posgrado e Investigacion (SEPI), Escuela Superior de IngenierIa Mecanica y Electrica (ESIME). Unidad profesional, AZCAPOTZALCO, Av. de las Granjas No. 682, Col. Sta. Catarina Azcapotzalco, C.P. 02550, Mexico D.F. (Mexico)

    2009-08-01

    In this paper, the case of Single Edge Notch (SEN) specimens subject to opening/compressive loading was analyzed; The loads are applied in several ratios to evaluate the influence of the specimen geometry, and the Stress Intensity Factor (SIF) K{sub 1} values on the directional stability of crack propagation. The main purpose of this work is to evaluate the behaviour of the fracture propagation, when modifying the geometry of the SEN specimen and different relationships of load tension/compression are applied. Additionally, the precision of the numerical and experimental analysis is evaluated to determine its reliability when solving this type of problems. The specimens are subjected to biaxial opening/compression loading; both results (numerical and experimental) are compared in order to evaluate the condition of directional stability on crack propagation. Finally, an apparent transition point related to the length of specimens was identified, in which the behaviour of values of SIF changes for different loading ratios.

  18. The Landau-de Gennes theory of nematic liquid crystals: Uniaxiality versus Biaxiality

    KAUST Repository

    Majumdar, Apala

    2011-12-01

    We study small energy solutions within the Landau-de Gennes theory for nematic liquid crystals, subject to Dirichlet boundary conditions. We consider two-dimensional and three-dimensional domains separately. In the two-dimensional case, we establish the equivalence of the Landau-de Gennes and Ginzburg-Landau theory. In the three-dimensional case, we give a new definition of the defect set based on the normalized energy. In the threedimensional uniaxial case, we demonstrate the equivalence between the defect set and the isotropic set and prove the C 1,α-convergence of uniaxial small energy solutions to a limiting harmonic map, away from the defect set, for some 0 < a < 1, in the vanishing core limit. Generalizations for biaxial small energy solutions are also discussed, which include physically relevant estimates for the solution and its scalar order parameters. This work is motivated by the study of defects in liquid crystalline systems and their applications.

  19. Method for measuring biaxial stress in a body subjected to stress inducing loads

    Science.gov (United States)

    Clotfelter, W. N. (Inventor)

    1977-01-01

    A method is described for measuring stress in test articles including the steps of obtaining for a calibrating specimen a series of transit time differentials between the second wave echo for a longitudinal wave and the first wave echo for each of a pair of shear waves propagated through the specimen as it is subjected to known stress load of a series of stress loads for thus establishing a series of indications of the magnitudes for stress loads induced in the specimen, and thereafter obtaining a transit time differential between the second wave echo for a longitudinal wave and the first wave echo for each of a pair of shear waves propagated in the planes of the stress axes of a test article and comparing the transit time differential thus obtained to the series of transit time differentials obtained for the specimen to determine the magnitude of biaxial stress in the test article.

  20. Potential drop crack growth monitoring in high temperature biaxial fatigue tests

    International Nuclear Information System (INIS)

    Fitzgerald, B.P.; Krempl, E.

    1993-01-01

    The present work describes a procedure for monitoring crack growth in high temperature, biaxial, low cycle fatigue tests. The reversing DC potential drop equipment monitors smooth, tubular type 304 stainless steel specimens during fatigue testing. Electrical interference from an induction heater is filtered out by an analog filter and by using a long integration time. A Fourier smoothing algorithm and two spline interpolations process the large data set. The experimentally determined electrical potential drop is compared with the theoretical electrostatic potential that is found by solving Laplace's equation for an elliptical crack in a semi-infinite conducting medium. Since agreement between theory and experiment is good, the method can be used to measure crack growth to failure from the threshold of detectability

  1. The effect of casting conditions on the biaxial flexural strength of glass-ceramic materials.

    Science.gov (United States)

    Johnson, A; Shareef, M Y; Walsh, J M; Hatton, P V; van Noort, R; Hill, R G

    1998-11-01

    To assess the effect of mould and glass casting temperatures on the biaxial flexural strength (BFS) of two different types of castable glass-ceramic, using existing laboratory equipment and techniques. Two castable glass-ceramic materials were evaluated. One glass (LG3) is based on SiO2-Al2O3-P2O5-CaO-CaF2, and is similar in composition to glasses used in the manufacture of glass-ionomer cements. The other glass (SG3) is based on SiO2-K2O-Na2O-CaO-CaF2, and is a canasite-based material. Both materials were used to produce discs of 12 mm diameter and 2 mm thickness using the same lost-wax casting process as used for metal castings. Mould temperatures of between 500 degrees C and 1000 degrees C and glass casting temperatures of between 1100 degrees C and 1450 degrees C were evaluated. The cast discs were cerammed and the biaxial flexural strength determined with a Lloyd 2000 R tester. A significant difference was found for the BFS in the range of mould temperatures evaluated, with the optimum investment mould temperature being 590 degrees C for LG3 and 610 degrees C for SG3 (p = 0.0002 and p = 0.019, respectively). No significant differences were seen between any of the glass casting temperatures evaluated. The mould temperature for castable glass-ceramic materials produced using the lost-wax casting process can have a significant effect on BFS. The optimum mould temperature may differ slightly depending on the type of material being used. The glass casting temperature of these materials does not appear to have a significant effect on BFS.

  2. Application of magnetomechanical hysteresis modeling to magnetic techniques for monitoring neutron embrittlement and biaxial stress

    International Nuclear Information System (INIS)

    Sablik, M.J.; Kwun, H.; Rollwitz, W.L.; Cadena, D.

    1992-01-01

    The objective is to investigate experimentally and theoretically the effects of neutron embrittlement and biaxial stress on magnetic properties in steels, using various magnetic measurement techniques. Interaction between experiment and modeling should suggest efficient magnetic measurement procedures for determining neutron embrittlement biaxial stress. This should ultimately assist in safety monitoring of nuclear power plants and of gas and oil pipelines. In the first six months of this first year study, magnetic measurements were made on steel surveillance specimens from the Indian Point 2 and D.C. Cook 2 reactors. The specimens previously had been characterized by Charpy tests after specified neutron fluences. Measurements now included: (1) hysteresis loop measurement of coercive force, permeability and remanence, (2) Barkhausen noise amplitude; and (3) higher order nonlinear harmonic analysis of a 1 Hz magnetic excitation. Very good correlation of magnetic parameters with fluence and embrittlement was found for specimens from the Indian Point 2 reactor. The D.C. Cook 2 specimens, however showed poor correlation. Possible contributing factors to this are: (1) metallurgical differences between D.C. Cook 2 and Indian Point 2 specimens; (2) statistical variations in embrittlement parameters for individual samples away from the stated men values; and (3) conversion of the D.C. Cook 2 reactor to a low leakage core configuration in the middle of the period of surveillance. Modeling using a magnetomechanical hysteresis model has begun. The modeling will first focus on why Barkhausen noise and nonlinear harmonic amplitudes appear to be better indicators of embrittlement than the hysteresis loop parameters

  3. UV protective zinc oxide coating for biaxially oriented polypropylene packaging film by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Lahtinen, Kimmo, E-mail: kimmo.lahtinen@lut.fi [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Kääriäinen, Tommi, E-mail: tommi.kaariainen@colorado.edu [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Johansson, Petri, E-mail: petri.johansson@tut.fi [Paper Converting and Packaging Technology, Tampere University of Technology, P.O.Box 589, FI-33101 Tampere (Finland); Kotkamo, Sami, E-mail: sami.kotkamo@tut.fi [Paper Converting and Packaging Technology, Tampere University of Technology, P.O.Box 589, FI-33101 Tampere (Finland); Maydannik, Philipp, E-mail: philipp.maydannik@lut.fi [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Seppänen, Tarja, E-mail: tarja.seppanen@lut.fi [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Kuusipalo, Jurkka, E-mail: jurkka.kuusipalo@tut.fi [Paper Converting and Packaging Technology, Tampere University of Technology, P.O.Box 589, FI-33101 Tampere (Finland); Cameron, David C., E-mail: david.cameron@miktech.fi [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland)

    2014-11-03

    Biaxially oriented polypropylene (BOPP) packaging film was coated with zinc oxide (ZnO) coatings by atomic layer deposition (ALD) in order to protect the film from UV degradation. The coatings were made at a process temperature of 100 °C using diethylzinc and water as zinc and oxygen precursors, respectively. The UV protective properties of the coatings were tested by using UV–VIS and infrared spectrometry, differential scanning calorimetry (DSC) and a mechanical strength tester, which characterised the tensile and elastic properties of the film. The results obtained with 36 and 67 nm ZnO coatings showed that the ZnO UV protective layer is able to provide a significant decrease in photodegradation of the BOPP film under UV exposure. While the uncoated BOPP film suffered a complete degradation after a 4-week UV exposure, the 67 nm ZnO coated BOPP film was able to preserve half of its original tensile strength and 1/3 of its elongation at break after a 6-week exposure period. The infrared analysis and DSC measurements further proved the UV protection of the ZnO coatings. The results show that a nanometre scale ZnO coating deposited by ALD is a promising option when a transparent UV protection layer is sought for polymer substrates. - Highlights: • Atomic layer deposited zinc oxide coatings were used as UV protection layers. • Biaxially oriented polypropylene (BOPP) film was well protected against UV light. • Formation of UV degradation products in BOPP was significantly reduced. • Mechanical properties of the UV exposed BOPP film were significantly improved.

  4. Effects of biaxial oscillatory shear stress on endothelial cell proliferation and morphology.

    Science.gov (United States)

    Chakraborty, Amlan; Chakraborty, Sutirtha; Jala, Venkatakrishna R; Haribabu, Bodduluri; Sharp, M Keith; Berson, R Eric

    2012-03-01

    Wall shear stress (WSS) on anchored cells affects their responses, including cell proliferation and morphology. In this study, the effects of the directionality of pulsatile WSS on endothelial cell proliferation and morphology were investigated for cells grown in a Petri dish orbiting on a shaker platform. Time and location dependent WSS was determined by computational fluid dynamics (CFD). At low orbital speed (50 rpm), WSS was shown to be uniform (0-1 dyne/cm(2)) across the bottom of the dish, while at higher orbital speed (100 and 150 rpm), WSS remained fairly uniform near the center and fluctuated significantly (0-9 dyne/cm(2)) near the side walls of the dish. Since WSS on the bottom of the dish is two-dimensional, a new directional oscillatory shear index (DOSI) was developed to quantify the directionality of oscillating shear. DOSI approached zero for biaxial oscillatory shear of equal magnitudes near the center and approached one for uniaxial pulsatile shear near the wall, where large tangential WSS dominated a much smaller radial component. Near the center (low DOSI), more, smaller and less elongated cells grew, whereas larger cells with greater elongation were observed in the more uniaxial oscillatory shear (high DOSI) near the periphery of the dish. Further, cells aligned with the direction of the largest component of shear but were randomly oriented in low magnitude biaxial shear. Statistical analyses of the individual and interacting effects of multiple factors (DOSI, shear magnitudes and orbital speeds) showed that DOSI significantly affected all the responses, indicating that directionality is an important determinant of cellular responses. Copyright © 2011 Wiley Periodicals, Inc.

  5. Effect of Molecular Flexibility on the Nematic-to-Isotropic Phase Transition for Highly Biaxial Molecular Non-Symmetric Liquid Crystal Dimers

    Science.gov (United States)

    Sebastián, Nerea; López, David Orencio; Diez-Berart, Sergio; de la Fuente, María Rosario; Salud, Josep; Pérez-Jubindo, Miguel Angel; Ros, María Blanca

    2011-01-01

    In this work, a study of the nematic (N)–isotropic (I) phase transition has been made in a series of odd non-symmetric liquid crystal dimers, the α-(4-cyanobiphenyl-4’-yloxy)-ω-(1-pyrenimine-benzylidene-4’-oxy) alkanes, by means of accurate calorimetric and dielectric measurements. These materials are potential candidates to present the elusive biaxial nematic (NB) phase, as they exhibit both molecular biaxiality and flexibility. According to the theory, the uniaxial nematic (NU)–isotropic (I) phase transition is first-order in nature, whereas the NB–I phase transition is second-order. Thus, a fine analysis of the critical behavior of the N–I phase transition would allow us to determine the presence or not of the biaxial nematic phase and understand how the molecular biaxiality and flexibility of these compounds influences the critical behavior of the N–I phase transition. PMID:28824100

  6. Les particules illocutoires, variable d’ajustement de la traduction sous-titrante au cinéma

    Directory of Open Access Journals (Sweden)

    Ève Vayssière

    2010-12-01

    Full Text Available Die illokutiven Partikel fungieren als Anpassungsvariable, die beim Übersetzungsakt zur Untertitelung von Filmen entweder weggelassen werden oder erscheinen. Wenn sie einfach gelöscht werden, ergeben sich weder grammatikalische Störungen noch Informationsverlust. Das Auftauchen dieser Partikel in den deutschen Untertiteln zeigt jedoch, wie wichtig sie sind: Als Partikel der Oralität tragen sie zur Idiomatizität bei.Les particules illocutoires sont des variables d’ajustement lors de l’acte de traduction sous-titrante au cinéma, elles peuvent être supprimées sans que cela occasionne de dysfonctionnement grammatical et elles disparaissent lors de la traduction en français sans que cela occasionne une perte d’informations. Leur apparition dans les sous-titres allemands montre néanmoins leur importance : particules de l’oralité, elles sont vecteur d’« idiomaticité ».

  7. Patrimonialiser les bases de sous-marins et le Mur de l’Atlantique

    Directory of Open Access Journals (Sweden)

    Claude Prelorenzo

    2011-06-01

    Full Text Available Le Mur de l’Atlantique court de la frontière espagnole jusqu’au nord de la Norvège. Au sein de ce dispositif sont installées cinq bases de sous-marins : Dunkerque, Saint-Nazaire, Lorient, La Rochelle et Bordeaux. Après une période de purgatoire, liée aux souvenirs trop frais des bombardements qu’ils ont attirés sur les villes, les édifices du mur sont entrés dans la sphère de la culture et du tourisme. Nous posons alors la question suivante : de quoi ces édifices portent-ils témoignage, et nous envisageons plusieurs aspects : leur évident modernisme qui les situe à un moment de l’histoire de l’architecture, leur hétérogénéité qui fait de ces bâtiments des sortes d’ovni, sans aucun rapport ni d’échelle ni de forme avec l’architecture civile, une technique d’enfouissement et de camouflage génératrice d’un nouveau paysage. Mais ces édifices peuvent-ils être exonérés de leur but guerrier ? Quel est le message de leur recyclage dans le culturel, le festif ou le commercial ? Deux bases de sous-marins sont plus particulièrement présentées, celle de Saint-Nazaire et celle de Lorient.The Atlantic Wall stretches from the Spanish border to northern Norway. Within this system there are five bases for submarines: Dunkirk, Saint-Nazaire, Lorient, La Rochelle and Bordeaux. After a period of purgatory, with the painful memories of the wartime air raids which destroyed the cities around the bases, the buildings which the Atlantic Wall comprises have now entered the spheres of culture and tourism. What do these buildings bear witness to? Their frank modernism puts them at a precise moment in the history of architecture. Their heterogeneity makes them like UFOs, without any relation of scale or form to civil architecture. Their specific techniques of dissimulation and camouflage created new landscapes. But can these buildings be freed from the memories of their original military purpose? What message is

  8. Effects of combined electron-beam irradiation and sous-vide treatments on microbiological and other qualities of chicken breast meat

    International Nuclear Information System (INIS)

    Shamsuzzaman, K.; Lucht, L.; Chuaqui-Offermanns, N.

    1994-01-01

    The microbiological safety, refrigeration shelf-life, and nutritional quality of chicken breast meat were investigated following combined electron-beam irradiation and cooking under vacuum (sous-vide). Chicken breast meat inoculated with 10 6 CFU/g of Listeria monocytogenes was irradiated with an electron beam at doses up to 3.1 kGy under vacuum in barrier bags, cooked in a boiling water bath for 3 min 45 s (previously determined to achieve an internal temperature of 71.1 o C), and stored at 8 o C for up to 5 weeks. Listeria was undetectable in samples treated with combined sous-vide and irradiation at 3.1 kGy, but the organism survived the sous-vide treatment without irradiation and multiplied during storage. A similar study, conducted with uninoculated chicken breast meat, revealed that the product which received both irradiation (3 kGy) and sous-vide treatment had a shelf-life of at least 8 weeks at 8 o C, whereas the unirradiated samples treated sous-vide spoiled in 16 days. Listeria was undetectable in combination treated samples, but some of the unirradiated sous-vide samples tested after long storage showed high levels of Listeria. Some loss of thiamine occurred with the combined treatments. (author)

  9. Production durable de légumes sous-utilisés en vue d'améliorer la ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Production durable de légumes sous-utilisés en vue d'améliorer la sécurité alimentaire en milieu ruralrity (Les légumes indigènes revêtent une importance capitale pour les femmes pauvres vivant en milieu rural, mais ont reçu, à ce jour, peu d'attention de la part des milieux de la recherche, du développement et des ...

  10. Active control of residual tool marks for freeform optics functionalization by novel biaxial servo assisted fly cutting.

    Science.gov (United States)

    Zhu, Zhiwei; To, Suet; Zhang, Shaojian

    2015-09-01

    The inherent residual tool marks (RTM) with particular patterns highly affect optical functions of the generated freeform optics in fast tool servo or slow tool servo (FTS/STS) diamond turning. In the present study, a novel biaxial servo assisted fly cutting (BSFC) method is developed for flexible control of the RTM to be a functional micro/nanotexture in freeform optics generation, which is generally hard to achieve in FTS/STS diamond turning. In the BSFC system, biaxial servo motions along the z-axis and side-feeding directions are mainly adopted for primary surface generation and RTM control, respectively. Active control of the RTM from the two aspects, namely, undesired effect elimination or effective functionalization, are experimentally demonstrated by fabricating a typical F-theta freeform surface with scattering homogenization and two functional microstructures with imposition of secondary phase gratings integrating both reflective and diffractive functions.

  11. Integral modeling and financial impact of the geothermal situation and power plant at Soultz-sous-Forets

    International Nuclear Information System (INIS)

    Heidinger, Ph.

    2010-01-01

    The science about deep Enhanced Geothermal Systems (EGS) is still an emerging process and for further spreading economics is the key of the technology. To understand the financial situation, a program for economic evaluation was developed. This software (Euronaut) is completely modularized and considers all cash flows. Projects like an EGS are wrapped into tree-like structures. Based on the results which were gained at Soultz-sous-Forets, two configurations were designed. The first EGS configuration consists of a simplified two well (doublet) system where the dependencies of all components (mainly the reservoir, wells, pumps and the heat-to-power conversion unit) are physically and economically linked together. The realization of these dependencies and their complex interactions enable a sensitivity analysis of the borehole depth and reservoir depth, respectively. As a result, depth dependent effective costs and revenues of an EGS plant with the geohydrological characteristics of Soultz-sous-Forets are determined. As a future development, the second configuration will adapt the actual situation at Soultz-sous-Forets with the individual features of all four wells (GPK1 - GPK4). Then, this model can be used for all kinds of sensitivity analyses to clarify the impact of certain components or to optimize the operation scheme; e.g. the flow rates. (author)

  12. Biaxial testing of canine annulus fibrosus tissue under changing salt concentrations

    Directory of Open Access Journals (Sweden)

    Jacques M. Huyghe

    2010-03-01

    Full Text Available The in vivo mechanics of the annulus fibrosus of the intervertebral disc is one of biaxial rather than uniaxial loading. The material properties of the annulus are intimately linked to the osmolarity in the tissue. This paper presents biaxial relaxation experiments of canine annulus fibrosus tissue under stepwise changes of external salt concentration. The force tracings show that stresses are strongly dependent on time, salt concentration and orientation. The force tracing signature of are sponse to a change instrain, is one of a jumpin stress that relaxes partly as the new strain is maintained. The force tracing signature of a stepwise change in salt concentration is a progressive monotonous change in stress towards a new equilibrium value. Although the number of samples does not allow any definitive quantitative conclusions, the trends may shed light on the complex interaction among the directionality of forces, strains and fiber orientation on one hand, and on the other hand, the osmolarity of the tissue. The dual response to a change in strain is understood as an immediate response before fluid flows in or out of the tissue, followed by a progressive readjustment of the fluid content in time because of the gradient in fluid chemical potential between the tissue and the surrounding solution.A mecânica in vivo do anel fibroso do disco intervertebral é baseada em carregamento biaxial ao invés de uniaxial. As propriedades materiais do anel estão intimamente ligadas à osmolaridade no tecido. O artigo apresenta experimentos de relaxação biaxiais do anel fibroso de um tecido canino sob mudanças abruptas na concentração externa de sal. A assinatura da força devido à mudança brusca de salinidade resulta em uma progressiva e monótona mudança na tensão em direção a um novo valor de equilíbrio. Embora o número de amostras não permita nenhuma conclusão quantitativa, as tendências podem abrir uma luz no entendimento das intera

  13. Electrically conducting oxide buffer layers on biaxially textured nickel alloy tapes by reel-to-reel MOCVD process

    International Nuclear Information System (INIS)

    Stadel, O; Samoilenkov, S V; Muydinov, R Yu; Schmidt, J; Keune, H; Wahl, G; Gorbenko, O Yu; Korsakov, I E; Melnikov, O V; Kaul, A R

    2006-01-01

    Reel-to-reel MOCVD process for continuous growth of electrically conducting buffer layers on biaxially textured Ni5W tapes has been developed. The new buffer layer architechture is presented: 200 nm (La, Ba) 2 CuO 4 /40 nm (La, Ba)MnO 3 /Ni5W. Constituting layers with high structural quality have been grown on moving tapes (in plane FWHM ≤ 6 0 and out of plane FWHM ≤ 3 0 )

  14. Corrosion Fatigue Crack Growth Behavior at Notched Hole in 7075 T6 Under Different Biaxial Stress Ratios

    Science.gov (United States)

    2016-08-18

    Subjected to Biaxial Cyclic Loads.” Engineering Fracture Mechanics , 78:1516- 1528, 2011. [37] Sih, G.C.. “A Special Theory of Crack Propagation...of Aeronautics and Astronautics Graduate School of Engineering and Management Air Force Institute of Technology Air University Air Education and...environments from pre- cracked notched circular hole in a 7075-T6 cruciform specimen using a fracture mechanics approach. With stress ratio of R

  15. Effect of surface acid etching on the biaxial flexural strength of two hot-pressed glass ceramics.

    Science.gov (United States)

    Hooshmand, Tabassom; Parvizi, Shaghayegh; Keshvad, Alireza

    2008-07-01

    The purpose of this study was to assess the effect of surface acid etching on the biaxial flexural strength of two hot-pressed glass ceramics reinforced by leucite or lithium disilicate crystals. Forty glass ceramic disks (14-mm diameter, 2-mm thick) consisting of 20 leucite-based ceramic disks (IPS Empress) and 20 lithia disilicate-based ceramic (IPS Empress 2) were produced by hot-pressing technique. All specimens were polished and then cleaned ultrasonically in distilled water. Ten specimens of each ceramic group were then etched with 9% hydrofluoric (HF) acid gel for 2 minutes and cleaned ultrasonically again. The biaxial flexural strength was measured by the piston-on-three-ball test in a universal testing machine. Data based on ten specimens in each group were analyzed by two-way ANOVA (alpha= 0.05). Microstructure of ceramic surfaces before and after acid etching was also examined by a scanning electron microscope. The mean biaxial flexural strength values for each group tested were (in MPa): nonetched IPS Empress = 118.6 +/- 25.5; etched IPS Empress = 102.9 +/- 15.4; nonetched IPS Empress 2 = 283.0 +/- 48.5; and etched IPS Empress 2 = 250.6 +/- 34.6. The results showed that the etching process reduced the biaxial flexural strengths significantly for both ceramic types (p= 0.025). No significant interaction between the ceramic type and etching process was found (p= 0.407). From the results, it was concluded that surface HF acid etching could have a weakening effect on hot-pressed leucite or lithia disilicate-based glass ceramic systems.

  16. Non-monotonic probability of thermal reversal in thin-film biaxial nanomagnets with small energy barriers

    Directory of Open Access Journals (Sweden)

    N. Kani

    2017-05-01

    Full Text Available The goal of this paper is to investigate the short time-scale, thermally-induced probability of magnetization reversal for an biaxial nanomagnet that is characterized with a biaxial magnetic anisotropy. For the first time, we clearly show that for a given energy barrier of the nanomagnet, the magnetization reversal probability of an biaxial nanomagnet exhibits a non-monotonic dependence on its saturation magnetization. Specifically, there are two reasons for this non-monotonic behavior in rectangular thin-film nanomagnets that have a large perpendicular magnetic anisotropy. First, a large perpendicular anisotropy lowers the precessional period of the magnetization making it more likely to precess across the x^=0 plane if the magnetization energy exceeds the energy barrier. Second, the thermal-field torque at a particular energy increases as the magnitude of the perpendicular anisotropy increases during the magnetization precession. This non-monotonic behavior is most noticeable when analyzing the magnetization reversals on time-scales up to several tens of ns. In light of the several proposals of spintronic devices that require data retention on time-scales up to 10’s of ns, understanding the probability of magnetization reversal on the short time-scales is important. As such, the results presented in this paper will be helpful in quantifying the reliability and noise sensitivity of spintronic devices in which thermal noise is inevitably present.

  17. Development and evolution of biaxial texture of rolled nickel tapes by ion beam bombardment for high Tc coated conductors

    International Nuclear Information System (INIS)

    Wang, S.S.; Wu, K.; Shi, K.; Liu, Q.; Han, Z.

    2004-01-01

    High quality YBa 2 Cu 3 O 7-x films on metallic substrates with high critical current densities well over 10 6 A/cm 2 can be prepared by the rolling assisted biaxially textured substrates (RABiTS) method. Nickel or its alloys have been used as biaxially textured substrates formed through a specific rolling and high temperature annealing procedures. In this paper, we report a newly developed process for developing biaxial texture in rolled Ni tape by argon ion beam bombardment. It is named the ion-beam structure modification (ISM) process. In the ISM processed Ni foils, X-ray diffraction ω scans showed the full width-half maximum (FWHM) value of the (2 0 0) peak was 5.7 deg. . And the electron back scattering diffraction (EBSP) analysis based on scanning electron microscopy showed good {1 0 0} cubic orientation and the mean grain size was determined as about 25 μm. The texture evolution of rolled Ni foils during ISM process is reported also. For ISM process, local temperature elevation and distribution arises from the ion bombardment, coupled with anisotropic incident ion penetration and propagation as a result of channeling effects in the metal lattice, are expected to play the major roles in the development of grain reorientation in the Ni foil. Due to the simplicity and efficiency of the ISM process, the technique shows a great promise for application in the industrial scale production of long-lengths of superconductor tapes

  18. Biaxial stress driven tetragonal symmetry breaking and high-temperature ferromagnetic semiconductor from half-metallic CrO2

    Science.gov (United States)

    Xiao, Xiang-Bo; Liu, Bang-Gui

    2018-03-01

    It is highly desirable to combine the full spin polarization of carriers with modern semiconductor technology for spintronic applications. For this purpose, one needs good crystalline ferromagnetic (or ferrimagnetic) semiconductors with high Curie temperatures. Rutile CrO2 is a half-metallic spintronic material with Curie temperature 394 K and can have nearly full spin polarization at room temperature. Here, we find through first-principles investigation that when a biaxial compressive stress is applied on rutile CrO2, the density of states at the Fermi level decreases with the in-plane compressive strain, there is a structural phase transition to an orthorhombic phase at the strain of -5.6 % , and then appears an electronic phase transition to a semiconductor phase at -6.1 % . Further analysis shows that this structural transition, accompanying the tetragonal symmetry breaking, is induced by the stress-driven distortion and rotation of the oxygen octahedron of Cr, and the half-metal-semiconductor transition originates from the enhancement of the crystal field splitting due to the structural change. Importantly, our systematic total-energy comparison indicates the ferromagnetic Curie temperature remains almost independent of the strain, near 400 K. This biaxial stress can be realized by applying biaxial pressure or growing the CrO2 epitaxially on appropriate substrates. These results should be useful for realizing full (100%) spin polarization of controllable carriers as one uses in modern semiconductor technology.

  19. On the field-induced switching of molecular organization in a biaxial nematic cell and its relaxation

    Science.gov (United States)

    Ricci, Matteo; Berardi, Roberto; Zannoni, Claudio

    2015-08-01

    We investigate the switching of a biaxial nematic filling a flat cell with planar homogeneous anchoring using a coarse-grained molecular dynamics simulation. We have found that an aligning field applied across the film, and acting on specific molecular axes, can drive the reorientation of the secondary biaxial director up to one order of magnitude faster than that for the principal director. While the π/2 switching of the secondary director does not affect the alignment of the long molecular axes, the field-driven reorientation of the principal director proceeds via a concerted rotation of the long and transversal molecular axes. More importantly, while upon switching off a (relatively) weak or intermediate field, the biaxial nematic liquid crystal is always able to relax to the initial surface aligned director state; this is not the case when using fields above a certain threshold. In that case, while the secondary director always recovers the initial state, the principal one remains, occasionally, trapped in a nonuniform director state due to the formation of domain walls.

  20. Improvement of microbiological safety of sous-vide meals by gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Farkas, J. E-mail: huto@omega.kee.hu; Polyak-Feher, K.; Andrassy, E.; Meszaros, L

    2002-03-01

    Experimental batches of smoked-cured pork in stewed beans sauce were inoculated with spores of psychrotrophic Bacillus cereus, more heat and radiation resistant than spores of non-proteolytic C. botulinum. After vacuum packaging, the meals were treated with combinations of pasteurizing heat treatments and gamma irradiation of 5 kGy. Prior and after treatments, and periodically during storage at 10 deg. C, total aerobic and total anerobic viable cell counts, and selectively, the viable cell counts of B. cereus and sulphite-reducing clostridia have been determined. The effects of the treatment order as well as addition of nisin to enhance the preservative efficiency of the physical treatments were also studied. Heat-sensitization of bacterial spores surviving irradiation occurred. The quality-friendly sous-vide cooking in combination with this medium dose gamma irradiation and/or nisin addition increased considerably the microbiological safety and the keeping quality of the meals studied. However, approx. 40% loss of thiamin content occurred as an effect of combination treatments, and adverse sensorial effects may also limit the feasible radiation doses or the usable concentrations of nisin.

  1. Improvement of microbiological safety of sous-vide meals by gamma radiation

    International Nuclear Information System (INIS)

    Farkas, J.; Polyak-Feher, K.; Andrassy, E.; Meszaros, L.

    2002-01-01

    Experimental batches of smoked-cured pork in stewed beans sauce were inoculated with spores of psychrotrophic Bacillus cereus, more heat and radiation resistant than spores of non-proteolytic C. botulinum. After vacuum packaging, the meals were treated with combinations of pasteurizing heat treatments and gamma irradiation of 5 kGy. Prior and after treatments, and periodically during storage at 10 deg. C, total aerobic and total anerobic viable cell counts, and selectively, the viable cell counts of B. cereus and sulphite-reducing clostridia have been determined. The effects of the treatment order as well as addition of nisin to enhance the preservative efficiency of the physical treatments were also studied. Heat-sensitization of bacterial spores surviving irradiation occurred. The quality-friendly sous-vide cooking in combination with this medium dose gamma irradiation and/or nisin addition increased considerably the microbiological safety and the keeping quality of the meals studied. However, approx. 40% loss of thiamin content occurred as an effect of combination treatments, and adverse sensorial effects may also limit the feasible radiation doses or the usable concentrations of nisin

  2. Shelf Life of Chicken Meat Balls Submitted to Sous Vide Treatment

    Directory of Open Access Journals (Sweden)

    ÖP Can

    2015-06-01

    Full Text Available The objective of this study was to investigate the appropriate temperature for processing storage of chicken meatballs made of minced chicken meat with the sous vide method. The chicken meatballs were prepared and separated into four experimental groups according to the application of heat treatment (10 and 20 minutes and storage time (+2 and +10°C. Sensory, microbiological (total aerobic mesophilic bacteria, total psychrotrophs, lactic acidbacteria, Enterobacteriaceae, Clostridiumperfringens, Listeria spp., chemical (pH, thiobarbituric acid, color (L*, a*, b* values, and texture profile analyses were performed on meatball samples. Cl. perfringens and Listeria spp. were not detected in meatball samples during the storage period. Samples cooked at 10 minute and stored at +2°C the highest count of total aerobic mesophilic bacteria (p<0.05. For lipid oxidation, interaction was observed between cooking time and storage temperature, with higher TBARs values for samples stored at 10 °C, while cooking time and storage temperature showed no influence on the color and textural analysis parameters. For the treatments evaluated, cooking time x storage temperature seem affect more microbiological and chemical parameters than color and textural parameters of chicken meatballs.

  3. Fuel elements for pressurised-gas reactors; Elements combustibles des piles a gaz sous pression

    Energy Technology Data Exchange (ETDEWEB)

    Stohr, J A; Englander, M; Gauthron, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    The design and fabrication of fuel elements for the first CO{sub 2} pressurized reactors have induced to investigate: various cladding materials, natural uranium base fuels, canning processes. The main analogical tests used in connection with the fuel element study are described. These various tests have enabled, among others, the fabrication of the fuel element for the EL2 reactor. Lastly, future solutions for electrical power producing reactors are foreseen. (author)Fren. [French] L'etude et la realisation d'elements combustibles pour les premieres piles a CO{sub 2} sous pression ont conduit a examiner: les divers materiaux de gaine, les combustibles a base d'uranium naturel, les modes de gainage. Les principaux essais analogiques ayant servi au cours de l'etude de la cartouche sont decrits. Ces divers essais ont notamment permis la realisation de la cartouche de la pile EL2. Enfin sont envisagees les solutions futures pour les piles productrices d'energie electrique. (auteur)

  4. Installation for analytic chemistry under irradiation; Installation de chimie analytique sous rayonnement

    Energy Technology Data Exchange (ETDEWEB)

    Fradin, J; Azoeuf, P; Guillon, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1966-07-01

    An installation has been set up for carrying out manipulations and chemical analyses on radioactive products. It is completely remote-controlled and is of linear shape, 15 metres long; it is made up of three zones: - an active zone containing the apparatus, - a rear zone giving access to the active zone, - a forward zone independent of the two others and completely protected from which the remote-control of the apparatus is effected. The whole assembly has been designed so that each apparatus corresponding to an analytical technique is set up in a sealed enclosure. The sealed enclosures are interconnected by a conveyor. After three years operation, a critical review is now made of the installation. (authors) [French] L'installation a ete realisee pour effectuer des manipulations et des analyses chimiques sur des produits radioactifs. Elle est totalement telecommandee et se presente sous une forme lineaire de 15 metres de longueur et comporte trois zones: - une zone active d'appareillage, - une zone arriere d'intervention, - une zone avant independante des deux premieres et totalement protegee, ou s'operent les telecommandes de l'appareillage. L'ensemble a ete concu de facon a ce que chaque appareillage correspondant a une technique d'analyse soit implante dans une enceinte etanche. Les enceintes etanches sont reliees entre elles par un convoyeur. Apres trois annees de fonctionnement nous faisons le bilan et les critiques de l'installation. (auteurs)

  5. Les tuméfactions sous mandibulaires: à propos de 42 cas et revue de la literature

    Science.gov (United States)

    Darouassi, Youssef; Mliha Touati, Mohamed; Chihani, Mehdi; Nadour, Karim; Ammar, Haddou; Bouaity, Brahim

    2014-01-01

    Les tuméfactions de la région sous mandibulaire sont une entité pathologique fréquente, caractérisées par un tableau clinique et une démarche diagnostique stéréotypée, et une unicité presque constante au plan chirurgical. Notre travail est une étude rétrospective sur une période de 5 an d'une série consécutive de 42 cas de tuméfactions sous mandibulaires qui ont été colligés au service d'oto-rhino-laryngologie et de chirurgie cervico-faciale de l'hôpital militaire Avicenne de Marrakech. L’âge moyen des patients était de 41 ans. Une prédominance masculine a été retrouvée. Le tableau clinique a été dominé par la tuméfaction sous mandibulaire. Tous les patients ont bénéficié d'une échographie cervicale. La tomodensitométrie cervicale a été réalisée chez 7 patients. La première étiologie était la sous maxillite chronique lithiasique dans 39,02% des cas. Le traitement était chirurgical dans tous les cas. En comparant les résultats avec ceux rapportés dans la littérature, nous allons discuter les différents aspects diagnostiques et thérapeutiques des étiologies les plus fréquentes. Les tuméfactions de la région sous mandibulaire sont fréquentes, nécessitant une démarche diagnostique rigoureuse et une prise en charge thérapeutique adaptée. PMID:25469195

  6. Numerical development of a new correlation between biaxial fracture strain and material fracture toughness for small punch test

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Pradeep [Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094 (India); Dutta, B.K., E-mail: bijon.dutta@gmail.com [Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094 (India); Chattopadhyay, J. [Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094 (India); Reactor Safety Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2017-04-01

    The miniaturized specimens are used to determine mechanical properties of the materials, such as yield stress, ultimate stress, fracture toughness etc. Use of such specimens is essential whenever limited quantity of material is available for testing, such as aged/irradiated materials. The miniaturized small punch test (SPT) is a technique which is widely used to determine change in mechanical properties of the materials. Various empirical correlations are proposed in the literature to determine the value of fracture toughness (J{sub IC}) using this technique. bi-axial fracture strain is determined using SPT tests. This parameter is then used to determine J{sub IC} using available empirical correlations. The correlations between J{sub IC} and biaxial fracture strain quoted in the literature are based on experimental data acquired for large number of materials. There are number of such correlations available in the literature, which are generally not in agreement with each other. In the present work, an attempt has been made to determine the correlation between biaxial fracture strain (ε{sub qf}) and crack initiation toughness (J{sub i}) numerically. About one hundred materials are digitally generated by varying yield stress, ultimate stress, hardening coefficient and Gurson parameters. Such set of each material is then used to analyze a SPT specimen and a standard TPB specimen. Analysis of SPT specimen generated biaxial fracture strain (ε{sub qf}) and analysis of TPB specimen generated value of J{sub i}. A graph is then plotted between these two parameters for all the digitally generated materials. The best fit straight line determines the correlation. It has been also observed that it is possible to have variation in J{sub i} for the same value of biaxial fracture strain (ε{sub qf}) within a limit. Such variation in the value of J{sub i} has been also ascertained using the graph. Experimental SPT data acquired earlier for three materials were then used to get J

  7. On the Landau-de Gennes Elastic Energy of a Q-Tensor Model for Soft Biaxial Nematics

    Science.gov (United States)

    Mucci, Domenico; Nicolodi, Lorenzo

    2017-12-01

    In the Landau-de Gennes theory of liquid crystals, the propensities for alignments of molecules are represented at each point of the fluid by an element Q of the vector space S_0 of 3× 3 real symmetric traceless matrices, or Q-tensors. According to Longa and Trebin (1989), a biaxial nematic system is called soft biaxial if the tensor order parameter Q satisfies the constraint tr(Q^2) = {const}. After the introduction of a Q-tensor model for soft biaxial nematic systems and the description of its geometric structure, we address the question of coercivity for the most common four-elastic-constant form of the Landau-de Gennes elastic free-energy (Iyer et al. 2015) in this model. For a soft biaxial nematic system, the tensor field Q takes values in a four-dimensional sphere S^4_ρ of radius ρ ≤ √{2/3} in the five-dimensional space S_0 with inner product = tr(QP). The rotation group it{SO}(3) acts orthogonally on S_0 by conjugation and hence induces an action on S^4_ρ \\subset {S}_0. This action has generic orbits of codimension one that are diffeomorphic to an eightfold quotient S^3/H of the unit three-sphere S^3, where H={± 1, ± i, ± j, ± k} is the quaternion group, and has two degenerate orbits of codimension two that are diffeomorphic to the projective plane RP^2. Each generic orbit can be interpreted as the order parameter space of a constrained biaxial nematic system and each singular orbit as the order parameter space of a constrained uniaxial nematic system. It turns out that S^4_ρ is a cohomogeneity one manifold, i.e., a manifold with a group action whose orbit space is one-dimensional. Another important geometric feature of the model is that the set Σ _ρ of diagonal Q-tensors of fixed norm ρ is a (geodesic) great circle in S^4_ρ which meets every orbit of S^4_ρ orthogonally and is then a section for S^4_ρ in the sense of the general theory of canonical forms. We compute necessary and sufficient coercivity conditions for the elastic energy by

  8. Multi-cracking in uniaxial and biaxial fatigue of 304L stainless steel

    International Nuclear Information System (INIS)

    Rupil, J.

    2012-01-01

    When a mechanical part is subjected to a repeated mechanical stress, it may be damaged after a number of cycles by several cracks initiation and propagation of a main crack. This is the phenomenon of fatigue damage. The thesis deals specifically with possible damage to some components of nuclear plants due to thermal fatigue. Unlike conventional mechanical fatigue damage where a main crack breaks the part, the thermal fatigue damage usually results in the appearance of a surface crack network. Two aspects are discussed in the thesis. The first is the experimental study of fatigue multiple cracking stage also called multi-cracking. Two mechanical test campaigns with multi-cracking detection by digital image correlation were conducted. These campaigns involve uniaxial and equi-biaxial mechanical loads in tension/compression without mean stress. This work allows to monitor and to observe the evolution of different networks of cracks through mechanical solicitations. The second is the numerical simulation of the phenomenon of fatigue damage. Several types of model are used (stochastic, probabilistic, cohesive finite elements). The experimental results have led to identify a multiple crack initiation law in fatigue which is faced with the numerical results. This comparison shows the relevance of the use of an analytical probabilistic model to find statistical results on the density of cracks that can be initiated with thermal and mechanical fatigue loadings. (author) [fr

  9. Bi-Axial Solar Array Drive Mechanism: Design, Build and Environmental Testing

    Science.gov (United States)

    Scheidegger, Noemy; Ferris, Mark; Phillips, Nigel

    2014-01-01

    The development of the Bi-Axial Solar Array Drive Mechanism (BSADM) presented in this paper is a demonstration of SSTL's unique space manufacturing approach that enables performing rapid development cycles for cost-effective products that meet ever-challenging mission requirements: The BSADM is designed to orient a solar array wing towards the sun, using its first rotation axis to track the sun, and its second rotation axis to compensate for the satellite orbit and attitude changes needed for a successful payload operation. The tight development schedule, with manufacture of 7 Flight Models within 1.5 year after kick-off, is offset by the risk-reduction of using qualified key component-families from other proven SSTL mechanisms. This allowed focusing the BSADM design activities on the mechanism features that are unique to the BSADM, and having an Engineering Qualification Model (EQM) built 8 months after kick-off. The EQM is currently undergoing a full environmental qualification test campaign. This paper presents the BSADM design approach that enabled meeting such a challenging schedule, its design particularities, and the ongoing verification activities.

  10. DEM Simulation of Biaxial Compression Experiments of Inherently Anisotropic Granular Materials and the Boundary Effects

    Directory of Open Access Journals (Sweden)

    Zhao-Xia Tong

    2013-01-01

    Full Text Available The reliability of discrete element method (DEM numerical simulations is significantly dependent on the particle-scale parameters and boundary conditions. To verify the DEM models, two series of biaxial compression tests on ellipse-shaped steel rods are used. The comparisons on the stress-strain relationship, strength, and deformation pattern of experiments and simulations indicate that the DEM models are able to capture the key macro- and micromechanical behavior of inherently anisotropic granular materials with high fidelity. By using the validated DEM models, the boundary effects on the macrodeformation, strain localization, and nonuniformity of stress distribution inside the specimens are investigated using two rigid boundaries and one flexible boundary. The results demonstrate that the boundary condition plays a significant role on the stress-strain relationship and strength of granular materials with inherent fabric anisotropy if the stresses are calculated by the force applied on the wall. However, the responses of the particle assembly measured inside the specimens are almost the same with little influence from the boundary conditions. The peak friction angle obtained from the compression tests with flexible boundary represents the real friction angle of particle assembly. Due to the weak lateral constraints, the degree of stress nonuniformity under flexible boundary is higher than that under rigid boundary.

  11. Localized strain measurements of the intervertebral disc annulus during biaxial tensile testing.

    Science.gov (United States)

    Karakolis, Thomas; Callaghan, Jack P

    2015-01-01

    Both inter-lamellar and intra-lamellar failures of the annulus have been described as potential modes of disc herniation. Attempts to characterize initial lamellar failure of the annulus have involved tensile testing of small tissue samples. The purpose of this study was to evaluate a method of measuring local surface strains through image analysis of a tensile test conducted on an isolated sample of annular tissue in order to enhance future studies of intervertebral disc failure. An annulus tissue sample was biaxial strained to 10%. High-resolution images captured the tissue surface throughout testing. Three test conditions were evaluated: submerged, non-submerged and marker. Surface strains were calculated for the two non-marker conditions based on motion of virtual tracking points. Tracking algorithm parameters (grid resolution and template size) were varied to determine the effect on estimated strains. Accuracy of point tracking was assessed through a comparison of the non-marker conditions to a condition involving markers placed on tissue surface. Grid resolution had a larger effect on local strain than template size. Average local strain error ranged from 3% to 9.25% and 0.1% to 2.0%, for the non-submerged and submerged conditions, respectively. Local strain estimation has a relatively high potential for error. Submerging the tissue provided superior strain estimates.

  12. Electron beam induced modifications in flexible biaxially oriented polyethylene terephthalate sheets: Improved mechanical and electrical properties

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhary, N. [Accelerator & Pulse Power Division, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Koiry, S.P. [Technical Physics Division, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Singh, A., E-mail: asb_barc@yahoo.com [Technical Physics Division, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Tillu, A.R. [Accelerator & Pulse Power Division, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Jha, P.; Samanta, S.; Debnath, A.K. [Technical Physics Division, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Aswal, D.K., E-mail: dkaswal@yahoo.com [Technical Physics Division, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Mondal, R.K. [Radiation Technology Development Division, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Acharya, S.; Mittal, K.C. [Accelerator & Pulse Power Division, Bhabha Atomic Research Centre, Mumbai, 400 085 (India)

    2017-03-01

    In the present work, we have studied the effects of electron beam irradiation (with dose ranging from 2 to 32 kGy) on mechanical and electrical properties of biaxially oriented polyethylene terephthalate (BOPET) sheets. The sol-gel analysis, Fourier transformation infra-red (FTIR), X-ray photoelectron spectroscopy (XPS) characterizations of the irradiated BOPET sheets suggest partial cross-linking of PET chains through the diethylene glycol (DEG). The mechanical properties of BOPET, such as, tensile strength, Young's modulus and electrical resistivity shows improvement with increasing dose and saturate for doses >10 kGy. The improved mechanical properties and high electrical resistivity of electron beam modified BOPET sheets may have additional advantages in applications, such as, packaging materials for food irradiation, medical product sterilization and electronic industries. - Graphical abstract: Irradiation of BOPET by electron beam leads to the formation of diethylene glycol that crosslink's the PET chains, resulting in improved mechanical properties and enhanced electrical resistivity. - Highlights: • BOPET exhibit improved tensile strength/Young's modulus after e-beam exposure. • Electrical resistivity of BOPET increases after e-beam exposure. • Cross-linking of PET chains through diethylene glycol was observed after e-beam exposure.

  13. General planar transverse domain walls realized by optimized transverse magnetic field pulses in magnetic biaxial nanowires

    Science.gov (United States)

    Li, Mei; Wang, Jianbo; Lu, Jie

    2017-02-01

    The statics and field-driven dynamics of transverse domain walls (TDWs) in magnetic nanowires (NWs) have attracted continuous interests because of their theoretical significance and application potential in future magnetic logic and memory devices. Recent results demonstrate that uniform transverse magnetic fields (TMFs) can greatly enhance the wall velocity, meantime leave a twisting in the TDW azimuthal distribution. For application in high-density NW devices, it is preferable to erase the twisting so as to minimize magnetization frustrations. Here we report the realization of a completely planar TDW with arbitrary tilting attitude in a magnetic biaxial NW under a TMF pulse with fixed strength and well-designed orientation profile. We smooth any twisting in the TDW azimuthal plane thus completely decouple the polar and azimuthal degrees of freedom. The analytical differential equation describing the polar angle distribution is derived and the resulting solution is not the Walker-ansatz form. With this TMF pulse comoving, the field-driven dynamics of the planar TDW is investigated with the help of the asymptotic expansion method. It turns out the comoving TMF pulse increases the wall velocity under the same axial driving field. These results will help to design a series of modern magnetic devices based on planar TDWs.

  14. Strain distribution and failure mode of polymer separators for Li-ion batteries under biaxial loading

    Science.gov (United States)

    Kalnaus, Sergiy; Kumar, Abhishek; Wang, Yanli; Li, Jianlin; Simunovic, Srdjan; Turner, John A.; Gorney, Phillip

    2018-02-01

    Deformation of polymer separators for Li-ion batteries has been studied under biaxial tension by using a dome test setup. This deformation mode provides characterization of separator strength under more complex loading conditions, closer representing deformation of an electric vehicle battery during crash event, compared to uniaxial tension or compression. Two polymer separators, Celgard 2325 and Celgard 2075 were investigated by deformation with spheres of three different diameters. Strains in separators were measured in situ by using Digital Image Correlation (DIC) technique. The results show consistent rupture of separators along the machine direction coinciding with areas of high strain accumulation. The critical first principal strain for failure was independent of the sphere diameter and was determined to be approximately 34% and 43% for Celgard 2325 and Celgard 2075 respectively. These values can be taken as a criterion for internal short circuit in a battery following an out-of-plane impact. A Finite Element (FE) model was built with the anisotropic description of separator behavior, derived from tensile tests in orthogonal directions. The results of simulations predicted the response of separator rather well when compared to experimental results for various sizes of rigid sphere.

  15. Evaluation of Biaxial Mechanical Properties of Aortic Media Based on the Lamellar Microstructure

    Directory of Open Access Journals (Sweden)

    Hadi Taghizadeh

    2015-01-01

    Full Text Available Evaluation of the mechanical properties of arterial wall components is necessary for establishing a precise mechanical model applicable in various physiological and pathological conditions, such as remodeling. In this contribution, a new approach for the evaluation of the mechanical properties of aortic media accounting for the lamellar structure is proposed. We assumed aortic media to be composed of two sets of concentric layers, namely sheets of elastin (Layer I and interstitial layers composed of mostly collagen bundles, fine elastic fibers and smooth muscle cells (Layer II. Biaxial mechanical tests were carried out on human thoracic aortic samples, and histological staining was performed to distinguish wall lamellae for determining the dimensions of the layers. A neo-Hookean strain energy function (SEF for Layer I and a four-parameter exponential SEF for Layer II were allocated. Nonlinear regression was used to find the material parameters of the proposed microstructural model based on experimental data. The non-linear behavior of media layers confirmed the higher contribution of elastic tissue in lower strains and the gradual engagement of collagen fibers. The resulting model determines the nonlinear anisotropic behavior of aortic media through the lamellar microstructure and can be assistive in the study of wall remodeling due to alterations in lamellar structure during pathological conditions and aging.

  16. Behavior of annealed type 316 stainless steel under monotonic and cyclic biaxial loading at room temperature

    International Nuclear Information System (INIS)

    Ellis, J.R.; Robinson, D.N.; Pugh, C.E.

    1978-01-01

    This paper addresses the elastic-plastic behavior of type 316 stainless steel, one of the major structural alloys used in liquid-metal fast breeder reactor components. The study was part of a continuing program to develop a structural design technology applicable to advanced reactor systems. Here, behaviour of solution annealed material was examined through biaxial stress experiments conducted at room temperature under radial loadings (√3tau=sigma) in tension-torsion stress space. The effects of both stress limited monotonic loading and strain limited cyclic loading were determined on the size, shape and position of yield loci corresponding to small offset strain (10 microstrain) definition of yield. In the present work, the aim was to determine the extent to which the constitutive laws previously recommended for type 304 stainless steel are applicable to type 316 stainless steel. It was concluded that for the conditions investigated, the inelastic behavior of the two materials are qualitatively similar. Specifically, the von Mises yield criterion provides a reasonable approximation of initial yield behavior and the subsequent hardening behavior, at least under small offset definitions of yield, is to the first order kinematic in nature. (Auth.)

  17. Biodegradable multilayer barrier films based on alginate/polyethyleneimine and biaxially oriented poly(lactic acid).

    Science.gov (United States)

    Gu, Chun-Hong; Wang, Jia-Jun; Yu, Yang; Sun, Hui; Shuai, Ning; Wei, Bing

    2013-02-15

    A layer-by-layer (LBL) approach was used to assemble alternating layers of sodium alginate (ALG)/polyethyleneimine (PEI) on biaxially oriented poly(lactic acid) (BOPLA) films in order to produce bio-based all-polymer thin films with low gas permeability. Increasing the depositing of ALG and PEI from 0 to 30 layers results in large thickness variations (from 0 to 3.92 μm). After 30 ALG/PEI layers are deposited, the resulting assembly has an OTR of 1.22 cm(3)/(m(2) day atm). When multiplied by thickness, the resulting oxygen permeability (OP) is found to be less than 3.8×10(-17) cm(3) cm/cm(2) s Pa, which is almost 3 orders of magnitude lower than that of uncoated BOPLA film (1.8×10(-14) cm(3)cm/cm(2) s Pa). At the same time, the resulting multilayer-coated BOPLA films maintain high optical clarity and tensile properties. This unique barrier thin film has become a promising alternative to non-biodegradable synthetic food packaging materials. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Development of partial safety factors for the design of partially prestressed rectangular sections in biaxial flexure

    International Nuclear Information System (INIS)

    Chatterjee, Aritra; Bhattacharya, Baidurya; Agrawal, Gunjan; Mondal, Apurba

    2011-01-01

    Partial safety factors (PSFs) used in reliability-based design are intended to account for uncertainties in load, material and mathematical modeling while ensuring that the target reliability is satisfied for the relevant class of structural components in the given load combination and limit state. This paper describes the methodology in detail for developing a set of optimal reliability-based PSFs for the design of rectangular partially prestressed concrete sections subjected to biaxial flexure. The mechanical formulation of the flexural limit state is based on the principle behind prestressed concrete design recommended by IS 1343 and SP16 and failure is defined as tensile cracking of concrete extending beyond the depth of cover. The applied moments are combined according to Wood's criteria. The optimization of the PSFs is based on reliability indices obtained from first order reliability analysis of the structural components; Monte Carlo simulations are performed in each run to determine the capacity statistics and dependence between capacity and applied loads (effected through the axial loads influencing moment capacity corresponding to cracking). Numerical examples involving flexural design of partially prestressed concrete shell elements in nuclear power plant containments under accidental pressure load combination are provided. (author)

  19. Biaxial Solar Tracking System Based on the MPPT Approach Integrating ICTs for Photovoltaic Applications

    Directory of Open Access Journals (Sweden)

    Raúl Gregor

    2015-01-01

    Full Text Available The smart grid and distributed generation based on renewable energy applications often involve the use of information and communication technology (ICT coupled with advanced control and monitoring algorithms to improve the efficiency and reliability of the electrical grid and renewable generation systems. Photovoltaic (PV systems have been recently applied with success in the fields of distributed generation due to their lower environmental impact where the electrical energy generation is related to the amount of solar irradiation and thus the angle of incident ray of the sun on the surface of the modules. This paper introduces an integration of ICTs in order to achieve the maximum power point tracking (MPPT using a biaxial solar tracking system for PV power applications. To generate the references for the digital control of azimuth and elevation angles a Global Positioning System (GPS by satellites is used which enables acquiring the geographic coordinates of the sun in real-time. As a total integration of the system a communication platform based on the 802.15.4 protocol for the wireless sensor networks (WSNs is adopted for supervising and monitoring the PV plant. A 2.4 kW prototype system is implemented to validate the proposed control scheme performance.

  20. Monitoring Local Changes in Granite Rock Under Biaxial Test: A Spatiotemporal Imaging Application With Diffuse Waves

    Science.gov (United States)

    Xie, Fan; Ren, Yaqiong; Zhou, Yongsheng; Larose, Eric; Baillet, Laurent

    2018-03-01

    Diffuse acoustic or seismic waves are highly sensitive to detect changes of mechanical properties in heterogeneous geological materials. In particular, thanks to acoustoelasticity, we can quantify stress changes by tracking acoustic or seismic relative velocity changes in the material at test. In this paper, we report on a small-scale laboratory application of an innovative time-lapse tomography technique named Locadiff to image spatiotemporal mechanical changes on a granite sample under biaxial loading, using diffuse waves at ultrasonic frequencies (300 kHz to 900 kHz). We demonstrate the ability of the method to image reversible stress evolution and deformation process, together with the development of reversible and irreversible localized microdamage in the specimen at an early stage. Using full-field infrared thermography, we visualize stress-induced temperature changes and validate stress images obtained from diffuse ultrasound. We demonstrate that the inversion with a good resolution can be achieved with only a limited number of receivers distributed around a single source, all located at the free surface of the specimen. This small-scale experiment is a proof of concept for frictional earthquake-like failure (e.g., stick-slip) research at laboratory scale as well as large-scale seismic applications, potentially including active fault monitoring.

  1. Analysis of biaxial strain in InN(0001) epilayers grown by molecular beam epitaxy

    International Nuclear Information System (INIS)

    Dimakis, E.; Domagala, J.; Iliopoulos, E.; Adikimenakis, A.; Georgakilas, A.

    2007-01-01

    The in-plane lattice parameters of InN, GaN and Al 2 O 3 in a InN/GaN/Al 2 O 3 (0001) heterostructure have been measured as a function of temperature in the range of 25-350 C, using high resolution X-ray diffraction. The results reveal that both the GaN and InN crystals follow the in-plane thermal expansion of the Al 2 O 3 substrate's lattice and there is no rearrangement of misfit dislocations at the InN/GaN and GaN/Al 2 O 3 interfaces. It was also found that either compressive or tensile character of residual biaxial strain is possible for the InN films, depending on the two-dimensional (2D) or three-dimensional (3D) growth mode of InN on the GaN(0001) buffer layer. The tensile strain is inherent to the nucleation and coalescence of 3D islands. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Particle flow of ceramic breeder pebble beds in bi-axial compression experiments

    International Nuclear Information System (INIS)

    Hermsmeyer, S.; Reimann, J.

    2002-01-01

    Pebble beds of Tritium breeding ceramic material are investigated within the framework of developing solid breeder blankets for future nuclear fusion power plants. For the thermo-mechanical characterisation of such pebble beds, bed compression experiments are the standard tools. New bi-axial compression experiments on 20 and 30 mm high pebble beds show pebble flow effects much more pronounced than in previous 10 mm beds. Owing to the greater bed height, conditions are reached where the bed fails in cross direction and unhindered flow of the pebbles occurs. The paper presents measurements for the orthosilicate and metatitanate breeder materials that are envisaged to be used in a solid breeder blanket. The data are compared with calculations made with a Drucker-Prager soil model within the finite-element code ABAQUS, calibrated with data from other experiments. It is investigated empirically whether internal bed friction angles can be determined from pebble beds of the considered heights, which would simplify, and broaden the data base for, the calibration of the Drucker-Prager pebble bed models

  3. Pulsed Source Measurements on a Uranium-Water Subcritical Assembly; Mesures Faites sur un Assemblage Sous- Critique Uranium-Eau Ordinaire a l'Aide d'une Source Pulsee; Izmereniya s pomoshch'yu istochnikov impul'snykh nejtronov na urano-vodnoi podkriticheskoi sborke; Mediciones con Fuentes Pulsantes en un Conjunto Subcritico Uranio-Agua

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, I. H.; Walker, J. [Department of Physics, University of Birmingham, Birmingham (United Kingdom)

    1964-02-15

    An unreflected assembly of natural uranium and light water has been used in conjunction with a pulsed source of neutrons for decay-time measurements at different bucklings. Four different lattice pitches over the range 3.94 cm to 5.08 cm were obtained by using different pairs of accurately machined lattice plates and in each case the uranium was in the form of bars 109.8 cm long and 3.0 cm diameter. The fuel- was mounted horizontally and loadings up to approximately 6 t were involved. Spatial harmonics were eliminated or selected by appropriate placing of a small scintillation detector. Experimental results showing the dependence of decay constant on buckling are presented and compared with theoretical values. (author) [French] On a utilise conjointement un assemblage sans reflecteur uranium naturel-eau ordinaire et une source puisee en vue de mesurer le temps de decroissance pour differents laplaciens. - Plusieurs paires de plaques de reseau usinees avec precision ont permis d'adopter quatre differents pas de reseau allant de 3,94cm a 5,08 cm; dans chaque cas, l'uranium etait sous forme de barres de 109,8 cm de long et de 3,0 cm de diametre. Le combustible etait monte horizontalement et le chargement a atteint parfois jusqu'a pres de 6 t. Grace a un petit detecteur a scintillations convenablement place, on a pu eliminer les harmoniques spatiaux ou les selectionner. Les auteurs presentent des resultats d'experiences qui montrent les variations de la constante de desintegration en fonction du laplacien, et les comparent avec les valeurs theoriques. (author) [Spanish] Los autores utilizaron un conjunto de uranio natural y agua ligera, sin reflector, juntamente con una fuente neutronica pulsante, para efectuar determinaciones del tiempo de desintegracion en correspondencia con diferentes valores del laplaciano. En este conjunto se pueden establecer cuatro diferentes espaciamientos del reticulado, desde 3,94 cm hasta 5,08 cm. utilizando diferentes pares de placas de

  4. Sigand : une application SIG sous androïd (tablette de la gestion des chantiers

    Directory of Open Access Journals (Sweden)

    CHAKIB SAFAR BATI

    2016-12-01

    Full Text Available L’introduction de données terrain pour les études environnementales ou de gestion de l’espace, régionales ou locales est une nécessité incontournable pour la validation des traitements et des interprétations mais aussi pour fournir des compléments d’informations aux divers travaux. Mais ce retour terrain est également de plus en plus demandé pour les gestionnaires de chantiers et de projets qui ont une exigence de contrôle ou de suivi et donc d’une information temps réel sur l’avancement des travaux, autrement pour introduire de nouvelles informations sur la base de données géoréférencées. Les avancées technologiques en matière de manipulation de l’information géographique (GPS, tablette graphique, téléphone portable, réalité augmentée permettent d’espérer la mise à dispositiondes professionnels, voire d’un plus large public, des outils adéquats pour de tels travaux. Actuellement, les outils d’élaboration, de gestion et d’exploitation des bases de données géographiques (solutions SIG ne sont pas encore complètement opérationnels en version « tablette » ; des applications telles que Qgis ou ArcGis sous Androïd attendent encore des développements. Nous présentons ici la première version d’une application SIG sous Androïd (disponible sur tablette pour la gestion en temps réel des chantiers qui permet de charger des couches vectorielles et de les mettre à jour sur le terrain en fonction de l’observation directe ; les couches (préalablement géoréférencées sont projetées sur des fonds cartographiques fournis par un serveur cartographique Google Maps (Route, Satellite, terrain; dans le cas d’absence de connexion internet, le fond cartographique est ramené d’un cache. Nous utilisons SpatialiteAndroïd pour le stockage et la manipulation des données géographiques. Le contrôleur de cartes Google Maps est employé pour afficher en mode cartographique les données stockées dans

  5. High pressure experimental water loop; Cellule experimentale a eau sous pression

    Energy Technology Data Exchange (ETDEWEB)

    Grenon, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Terny, M [Societe Grenobloise d' Etudes et d' Applications Hydrauliques, 38 (France)

    1958-07-01

    A high pressure experimental water loop has been made for studying the detection and evolution of cladding failure in a pressurized reactor. The loop has been designed for a maximum temperature of 360 deg. C, a maximum of 160 kg/cm{sup 2} and flow rates up to 5 m{sup 3}/h. The entire loop consists of several parts: a main circuit with a canned rotor circulation pump, steam pressurizer, heating tubes, two hydro-cyclones (one de-gasser and one decanter) and one tubular heat exchanger; a continuous purification loop, connected in parallel, comprising pressure reducing valves and resin pots which also allow studies of the stability of resins under pressure, temperature and radiation; following the gas separator is a gas loop for studying the recombination of the radiolytic gases in the steam phase. The preceding circuits, as well as others, return to a low pressure storage circuit. The cold water of the low pressure storage flask is continuously reintroduced into the high pressure main circuit by means of a return pump at a maximum head of 160 kg /cm{sup 2}, and adjusted to the pressurizer level. This loop is also a testing bench for the tight high pressure apparatus. The circulating pump and the connecting flanges (Oak Ridge type) are water-tight. The feed pump and the pressure reducing valves are not; the un-tight ones have a system of leak recovery. To permanently check the tightness the circuit has been fitted with a leak detection system (similar to the HRT one). (author)Fren. [French] Une cellule experimentale a eau sous pression a ete realisee pour l'etude de l'evolution et de la detection de ruptures de gaines dans le cas d'un reacteur pressurise. Les performances de ce circuit sont: 350 deg. C maximum pour la temperature et 160 kg/cm{sup 2} maximum pour la pression, le debit pouvant atteindre 5 m{sup 3}/h. Le circuit complet est constitue de plusieurs parties: un circuit principal avec pompe de circulation a rotor immerge, preiseur a vapeur, tubes chaudieres

  6. Investigation of persistent Multiplets at the EGS reservoir of Soultz-Sous-Forêts, France

    Science.gov (United States)

    Lengliné, O.; Cauchie, L.; Schmittbuhl, J.

    2017-12-01

    During the exploitation of geothermal reservoirs, abundant seismicity is generally observed, especially during phases of hydraulic stimulations. The induced seismicity at the Enhanced Geothermal System of Soultz-Sous-Forêts in France, has been thoroughly studied over the years of exploitation. The mechanism at its origin has been related to both fluid pressure increases during stimulation and aseismic creeping movements. The fluid-induced seismic events often exhibit a high degree of similarity and the mechanism at the origin of these repeated events is thought to be associated with slow slip process where asperities on the rupture zone act several times.To have a better understanding of the mechanisms associated with such events and on the damaged zones involved during the hydraulic stimulations, we investigate the behavior of the multiplets and their persistent nature over several water injection intervals. For this purpose, we analyzed large datasets recorded from a borehole seismic network for several water injection periods (1993, 2000). For each stimulation interval, thousands of events are recorded at depth. We detected the events using a STA/LTA approach and classified them into families of comparable waveforms using an approach based on cross-correlation analysis. Classification of the seismic events is then improved depending on their location within the multiplets. For this purpose, inter-event distances within multiplets are examined and determined from cross-correlation analysis between pairs of events. These distances are then compared to the source dimensions derived from the estimation of the corner frequencies estimation. The multiplets properties (location, events size) are then investigated within and over several hydraulic tests. Hopefully these steps will lead to increase the knowledge on the repetitive nature of these events and the investigation of their persistence will outline the heterogeneities of the structures (regional stress

  7. Experimental Studies on Strength Behaviour of Notched Glass/Epoxy Laminated Composites under Uni-axial and Bi-axial Loading

    Science.gov (United States)

    Guptha, V. L. Jagannatha; Sharma, Ramesh S.

    2017-11-01

    The use of FRP composite materials in aerospace, aviation, marine, automotive and civil engineering industry has increased rapidly in recent years due to their high specific strength and stiffness properties. The structural members contrived from such composite materials are generally subjected to complex loading conditions and leads to multi-axial stress conditions at critical surface localities. Presence of notches, much required for joining process of composites, makes it further significant. The current practice of using uni-axial test data alone to validate proposed material models is inadequate leading to evaluation and consideration of bi-axial test data. In order to correlate the bi-axial strengths with the uni-axial strengths of GFRP composite laminates in the presence of a circular notch, bi-axial tests using four servo-hydraulic actuators with four load cells were carried out. To determine the in-plane strength parameters, bi-axial cruciform test specimen model was considered. Three different fibre orientations, namely, 0°, 45°, and 90° are considered with a central circular notch of 10 mm diameter in the present investigation. From the results obtained, it is observed that there is a reduction in strength of 5.36, 2.41 and 13.92% in 0°, 45°, and 90° fibre orientation, respectively, under bi-axial loading condition as compared to that of uni-axial loading in laminated composite.

  8. Green-Kubo relations for the viscosity of biaxial nematic liquid crystals

    Science.gov (United States)

    Sarman, Sten

    1996-09-01

    We derive Green-Kubo relations for the viscosities of a biaxial nematic liquid crystal. In this system there are seven shear viscosities, three twist viscosities, and three cross coupling coefficients between the antisymmetric strain rate and the symmetric traceless pressure tensor. According to the Onsager reciprocity relations these couplings are equal to the cross couplings between the symmetric traceless strain rate and the antisymmetric pressure. Our method is based on a comparison of the microscopic linear response generated by the SLLOD equations of motion for planar Couette flow (so named because of their close connection to the Doll's tensor Hamiltonian) and the macroscopic linear phenomenological relations between the pressure tensor and the strain rate. In order to obtain simple Green-Kubo relations we employ an equilibrium ensemble where the angular velocities of the directors are identically zero. This is achieved by adding constraint torques to the equations for the molecular angular accelerations. One finds that all the viscosity coefficients can be expressed as linear combinations of time correlation function integrals (TCFIs). This is much simpler compared to the expressions in the conventional canonical ensemble, where the viscosities are complicated rational functions of the TCFIs. The reason for this is, that in the constrained angular velocity ensemble, the thermodynamic forces are given external parameters whereas the thermodynamic fluxes are ensemble averages of phase functions. This is not the case in the canonical ensemble. The simplest way of obtaining numerical estimates of viscosity coefficients of a particular molecular model system is to evaluate these fluctuation relations by equilibrium molecular dynamics simulations.

  9. Redesigning axial-axial (biaxial) cruciform specimens for very high cycle fatigue ultrasonic testing machines.

    Science.gov (United States)

    Montalvão, Diogo; Wren, Andrew

    2017-11-01

    The necessity to increase performances in terms of lifetime and security in mechanical components or structures is the motivation for intense research in fatigue. Applications range from aeronautics to medical devices. With the development of new materials, there is no longer a fatigue limit in the classical sense, where it was accepted that the fatigue limit is the stress level such that there is no fracture up to 1E7 cycles. The recent development of ultrasonic testing machines where frequencies can go as high as 20 kHz or over enabled tests to be extended to ranges larger than 1E9 in just a few days. This area of studies is now known as Very High Cycle Fatigue (VHCF). On the other hand, most of the existing test equipment in the market for both classical and VHCF are uniaxial test machines. However, critical components used in Engineering applications are usually subjected to complex multi-axial loading conditions. In this paper, it is presented the methodology to redesigning existing cruciform test specimens that can be used to create an in-plane biaxial state of stress when used in 'uniaxial' VHCF ultrasonic testing machines (in this case, the term 'uniaxial' is used not because of the state of stress created at the centre of the specimen, but because of the direction at which the load is applied). The methodology is explained in such a way that it can be expanded to other existing designs, namely cruciform designs, that are not yet used in VHCF. Also, although the approach is presented in simple and logical terms, it may not be that obvious for those who have a more focused approach on fatigue rather than on modal analysis. It is expected that by contributing to bridging the gap between the sciences of modal analysis and fatigue, this research will help and encourage others exploiting new capabilities in VHCF.

  10. Dependence of electronic properties of germanium on the in-plane biaxial tensile strains

    Energy Technology Data Exchange (ETDEWEB)

    Yang, C.H. [State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications (BUPT), Beijing 100876 (China); Yu, Z.Y., E-mail: yuzhongyuan30@gmail.com [State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications (BUPT), Beijing 100876 (China); Liu, Y.M.; Lu, P.F. [State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications (BUPT), Beijing 100876 (China); Gao, T. [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China); Li, M.; Manzoor, S. [State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications (BUPT), Beijing 100876 (China)

    2013-10-15

    The hybrid HSE06 functional with the spin–orbit coupling effects is used to calculate the habituation of the electronic properties of Ge on the (0 0 1), (1 1 1), (1 0 1) in-plane biaxial tensile strains (IPBTSs). Our motivation is to explore the nature of electronic properties of tensile-strained Ge on different substrate orientations. The calculated results demonstrate that one of the most effective and practical approaches for transforming Ge into a direct transition semiconductor is to introduce (0 0 1) IPBTS to Ge. At 2.3% (0 0 1) IPBTS, Ge becomes a direct bandgap semiconductor with 0.53 eV band gap, in good agreement with the previous theoretical and experimental results. We find that the (1 1 1) and (1 0 1) IPBTSs are not efficient since the shear strain and inner displacement of atoms introduced by them quickly decrease the indirect gap of Ge. By investigating the dependence of valence band spin–orbit splitting on strain, we prove that the dependency relationship and the coupled ways between the valence-band states of tensile-strained Ge are closely related to the symmetry of strain tensor, i.e., the symmetry of the substrate orientation. The first- and second-order coefficients describing the dependence of indirect gap, direct gap, the valence band spin–orbit coupling splitting, and heavy-hole–light-hole splitting of Ge on IPBTSs have been obtained by the least squares polynomial fitting. These coefficients are significant to quantitatively modulate the electronic properties of Ge by tensile strain and design tensile-strained Ge devices by semiconductor epitaxial technique.

  11. Cyclic plasticity of an austenitic-ferritic stainless steel under biaxial non proportional loading

    International Nuclear Information System (INIS)

    Aubin, V.

    2001-11-01

    Austenitic-ferritic stainless steels are supplied since about 30 years only, so they are yet not well-known. Their behaviour in cyclic plasticity was studied under uniaxial loading but not under multiaxial loading, whereas only a thorough knowledge of the phenomena influencing the mechanical behaviour of a material enables to simulate and predict accurately its behaviour in a structure. This work aims to study and model the behaviour of a duplex stainless steel under cyclic biaxial loading. A three step method was adopted. A set of tension-torsion tests on tubular specimen was first defined. We studied the equivalence between loading directions, and then the influence of loading path and loading history on the stress response of the material. Results showed that duplex stainless steel shows an extra-hardening under non proportional loading and that its behaviour depends on previous loading. Then, in order to analyse the results obtained during this first experimental stage, the yield surface was measured at different times during cyclic loading of the same kind. A very small plastic strain offset (2*10 -5 ) was used in order not to disturb the yield surface measured. The alteration of isotropic and kinematic hardening variables were deduced from these measures. Finally, three phenomenological constitutive laws were identified with the experimental set. We focused our interest on the simulation of stabilized stress levels and on the simulation of the cyclic hardening/softening behaviour. The comparison between experimental and numerical results enabled the testing of the relevance of these models. (authors)

  12. Valence band structure and density of states effective mass model of biaxial tensile strained silicon based on k · p theory

    International Nuclear Information System (INIS)

    Kuang Qian-Wei; Liu Hong-Xia; Wang Shu-Long; Qin Shan-Shan; Wang Zhi-Lin

    2011-01-01

    After constructing a stress and strain model, the valence bands of in-plane biaxial tensile strained Si is calculated by k · p method. In the paper we calculate the accurate anisotropy valance bands and the splitting energy between light and heavy hole bands. The results show that the valance bands are highly distorted, and the anisotropy is more obvious. To obtain the density of states (DOS) effective mass, which is a very important parameter for device modeling, a DOS effective mass model of biaxial tensile strained Si is constructed based on the valance band calculation. This model can be directly used in the device model of metal—oxide semiconductor field effect transistor (MOSFET). It also a provides valuable reference for biaxial tensile strained silicon MOSFET design. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  13. Design of a cruciform bend specimen for determination of out-of- plane biaxial tensile stress effects on fracture toughness for shallow cracks

    International Nuclear Information System (INIS)

    Bass, B.R.; Bryson, J.W.; Mcafee, W.J.; Pennell, W.E.; Theiss, T.J.

    1993-01-01

    Pressurized-thermal-shock loading in a reactor pressure vessel produces significant positive out-of-plane stresses along the crack front for both circumferential and axial cracks. Experimental evidence, while very limited, seems to indicate that a reduction in toughness is associated with out-of-plane biaxial loading when compared with toughness values obtained under uniaxial conditions. A testing program is described that seeks to determine the effects of out-of-plane biaxial tensile loading on fracture toughness of RPV steels. A cruciform bend specimen that meets specified criteria for the testing pregam is analyzed using three-dimensional elastic-plastic finite-element techniques. These analysis results provide the basis for proposed test conditions that are judged likely to produce a biaxial loading effect in the cruciform bend specimen

  14. Faulting mechanisms and stress regime at the European HDR site of Soultz-sous-Forets, France

    International Nuclear Information System (INIS)

    Cuenot, Nicolas; Charlety, Jean; Haessler, Henri; Dorbath, Louis

    2006-01-01

    The state of stress and its implications for shear on fault planes during fluid injection are crucial issues for the HDR (Hot Dry Rock) or EGS (Enhanced or Engineered Geothermal System) concept. This is especially true for hydraulic stimulation experiments, aimed at enhancing the connectivity of a borehole to the natural fracture network, since they tend to induce the shearing of fractures, which is controlled by the local stress regime. During the 2000 and 2003 stimulation tests at Soultz-sous-Forets, France, about 10,000 microearthquakes were located with a surface seismological network. Hundreds of double-couple (DC) focal mechanisms were automatically determined from first-motion polarities using the FPFIT program [Reasenberg, P.A., Oppenheimer, D., 1985. FPFIT, FPPLOT and FPPAGE: Fortran computer programs for calculating and displaying earthquake fault-plane solutions. US Geological Survey Open-File Report 85-739, 25 pp.]. The majority of these mechanisms indicate normal-faulting movement with a more or less pronounced strike-slip component. Some quasi-pure strike-slip events also occurred, especially in the deeper part of the stimulated rock volume, at more than 5 km depth. Although we found a double-couple solution for all events, we tried to observe and quantify the proportion of the non-double-couple (NDC) component in the seismic moment tensor for several microseisms from the 2003 data. The study shows that the NDC is higher for the events in the vicinity of the injection well than for the events far from the well. We used the method of Rivera and Cisternas [Rivera, L., Cisternas, A., 1990. Stress tensor and fault-plane solutions for a population of earthquakes. Bull. Seismol. Soc. Am. 80, 600-614.] to perform the inversion of the deviatoric part of the stress tensor from P-wave polarities. This method was applied to different datasets from the 2000 test, taken from the shallower and deeper parts of the stimulated region. The results show a stable

  15. Faulting mechanisms and stress regime at the European HDR site of Soultz-sous-Forets, France

    Energy Technology Data Exchange (ETDEWEB)

    Cuenot, Nicolas; Charlety, Jean; Haessler, Henri [Institut de Physique du Globe de Strasbourg, Ecole et Observatoire des Sciences de la Terre (IPGS-EOST), 5 rue Rene Descartes, 67084 Strasbourg Cedex (France); Dorbath, Louis [Institut de Physique du Globe de Strasbourg, Ecole et Observatoire des Sciences de la Terre (IPGS-EOST), 5 rue Rene Descartes, 67084 Strasbourg Cedex (France); Institut de Recherche pour le Developpement, Laboratoire des Mecanismes et Transferts en Geologie (IRD, LMTG), 14 Avenue Edouard Belin, 31400 Toulouse (France)

    2006-10-15

    The state of stress and its implications for shear on fault planes during fluid injection are crucial issues for the HDR (Hot Dry Rock) or EGS (Enhanced or Engineered Geothermal System) concept. This is especially true for hydraulic stimulation experiments, aimed at enhancing the connectivity of a borehole to the natural fracture network, since they tend to induce the shearing of fractures, which is controlled by the local stress regime. During the 2000 and 2003 stimulation tests at Soultz-sous-Forets, France, about 10,000 microearthquakes were located with a surface seismological network. Hundreds of double-couple (DC) focal mechanisms were automatically determined from first-motion polarities using the FPFIT program [Reasenberg, P.A., Oppenheimer, D., 1985. FPFIT, FPPLOT and FPPAGE: Fortran computer programs for calculating and displaying earthquake fault-plane solutions. US Geological Survey Open-File Report 85-739, 25 pp.]. The majority of these mechanisms indicate normal-faulting movement with a more or less pronounced strike-slip component. Some quasi-pure strike-slip events also occurred, especially in the deeper part of the stimulated rock volume, at more than 5 km depth. Although we found a double-couple solution for all events, we tried to observe and quantify the proportion of the non-double-couple (NDC) component in the seismic moment tensor for several microseisms from the 2003 data. The study shows that the NDC is higher for the events in the vicinity of the injection well than for the events far from the well. We used the method of Rivera and Cisternas [Rivera, L., Cisternas, A., 1990. Stress tensor and fault-plane solutions for a population of earthquakes. Bull. Seismol. Soc. Am. 80, 600-614.] to perform the inversion of the deviatoric part of the stress tensor from P-wave polarities. This method was applied to different datasets from the 2000 test, taken from the shallower and deeper parts of the stimulated region. The results show a stable

  16. Traduction audiovisuelle : quand le sous-titrage à destination des personnes sourdes et malentendantes se rencontrent dans le film "Le Prénom"

    OpenAIRE

    Horii, Anaïk

    2015-01-01

    La traduction audiovisuelle est riche en méthodes de traduction : doublage, voice over, sur-titrage, audiodescription, etc. Ce mémoire se concentre sur la méthode du sous-titrage ainsi que sur celle du sous-titrage à destination des personnes sourdes et malentendantes. Le but était de comparer ces deux méthodes de traduction interlinguistique (dans les deux cas pour un public germanophone) en s'attardant sur les références culturelles ainsi que sur les langages populaire, familier et argotiqu...

  17. Influence of Sous Vide and water immersion processing on polyacetylene content and instrumental color of parsnip (Pastinaca sativa) disks.

    Science.gov (United States)

    Rawson, Ashish; Koidis, Anastasios; Rai, Dilip K; Tuohy, Maria; Brunton, Nigel

    2010-07-14

    The effect of blanching (95 +/- 3 degrees C) followed by sous vide (SV) processing (90 degrees C for 10 min) on levels of two polyacetylenes in parsnip disks immediately after processing and during chill storage was studied and compared with the effect of water immersion (WI) processing (70 degrees C for 2 min.). Blanching had the greatest influence on the retention of polyacetylenes in sous vide processed parsnip disks resulting in significant decreases of 24.5 and 24% of falcarinol (1) and falcarindiol (2) respectively (p processing did not result in additional significant losses in polyacetylenes compared to blanched samples. Subsequent anaerobic storage of SV processed samples resulted in a significant decrease in 1 levels (p levels was observed (p > 0.05). 1 levels in WI processed samples were significantly higher than in SV samples (p processing with losses of up to 70% occurring after 5 days storage. 1 type polyacetylene undergoes degradation such as oxidation, dehydrogenation when thermally treated forming oxidized form of 1 type molecules, in this case falcarindione, dehydrofalcarinol, dehydrofalcarinone. Thermal processing had a significant effect on instrumental color of parsnip samples compared to minimally processed in both SV and WI processed samples resulting in parsnip disks becoming darker, yellower and browner following processing and storage.

  18. Effect of saliva and blood contamination on the bi-axial flexural strength and setting time of two calcium-silicate based cements: Portland cement and biodentine.

    Science.gov (United States)

    Alhodiry, W; Lyons, M F; Chadwick, R G

    2014-03-01

    This study evaluated the effect of contamination with saliva and blood on the bi-axial flexural strength and setting time of pure gray Portland cement and Biodentine (Septodont, Allington, UK). A one-way ANOVA showed that contamination caused no significant difference between the cements in bi-axial flexural strength (P> 0.05). However there was a significant difference in setting time (PPortland cement taking longer than Biodentine, regardless of the contaminant, and contamination with blood increased the setting time of both materials. Biodentine was similar in strength to Portland cement, but had a shorter setting time for both contaminated and non-contaminated samples.

  19. Effect of shallow angles on compressive strength of biaxial and triaxial laminates.

    Science.gov (United States)

    Jia, Hongli; Yang, Hyun-Ik

    2016-01-01

    Biaxial (BX) and triaxial (TX) composite laminates with ±45° angled plies have been widely used in wind turbine blades. As the scale of blades increases, BX and TX laminates with shallow-angled plies (i.e. off-axis ply angle shallow-angled BX and TX laminates are critical considering their locations in a wind turbine blade, and therefore in this study, the uniaxial static compression tests were conducted using BX and TX laminates with angled-plies of ±45°, ±35°, and ±25°, for the purpose of evaluation. On the other hand, Mori-Tanaka mean field homogenization method was employed to predict elastic constants of plies in BX and TX laminates involved in tests; linear regression analyses of experimentally measured ply strengths collected from various sources were then performed to estimate strengths of plies in BX and TX laminates; finally, Tsai-Wu, Hashin, and Puck failure criteria were chosen to predict compressive strengths of BX and TX laminates. Comparison between theoretical predictions and test results were carried out to illustrate the effectiveness of each criterion. The compressive strength of BX laminate decreases as ply angle increases, and the trend was successfully predicted by all three failure criteria. For TX laminates, ±35° angled plies rather than ±45° angled plies led to the lowest laminate compressive strength. Hashin and Puck criteria gave good predictions at certain ply angles for TX laminates, but Tsai-Wu criterion was able to capture the unexpected strength variation of TX laminates with ply angle. It was concluded that the transverse tensile stress in 0° plies of TX laminates, which attains its maximum when the off-axis ply angle is 35°, is the dominant factor in failure determination if using Tsai-Wu criterion. This explains the unexpected strength variation of TX laminates with ply angle, and also indicates that proper selection of ply angle is the key to fully utilizing the advantages of shallow-angled laminates.

  20. Biaxially oriented CdTe films on glass substrate through nanostructured Ge/CaF2 buffer layers

    Science.gov (United States)

    Lord, R. J.; Su, P.-Y.; Bhat, I.; Zhang, S. B.; Lu, T.-M.; Wang, G.-C.

    2015-09-01

    Heteroepitaxial CdTe films were grown by metal organic chemical vapor deposition on glass substrates through nanostructured Ge/CaF2 buffer layers which were biaxially oriented. It allows us to explore the structural properties of multilayer biaxial semiconductor films which possess small angle grain boundaries and to test the principle of a solar cell made of such low-cost, low-growth-temperature semiconductor films. Through the x-ray diffraction and x-ray pole figure analysis, the heteroepitaxial relationships of the mutilayered films are determined as [111] in the out-of-plane direction and CdTe//Ge//{ }{{{CaF}}2} in the in-plane direction. The I-V curves measured from an ITO/CdS/CdTe/Ge/CaF2/glass solar cell test structure shows a power conversion efficiency of ˜η = 1.26%, illustrating the initial success of such an approach. The observed non-ideal efficiency is believed to be due to a low shunt resistance and high series resistance as well as some residual large-angle grain boundary effects, leaving room for significant further improvement.

  1. Development of a hysteresis model for R/C columns subjected to bi-axial lateral loading

    International Nuclear Information System (INIS)

    Dutta, Sekhar Chandra; Chowdhury, Rajib; Roy, Raghupati; Reddy, G. Rami

    2003-01-01

    Recent investigations on dynamic response of reinforced concrete (R/C) structures have confirmed that the R/C structural members undergo much more inelastic deformation in each of the two mutually perpendicular directions under bi-directional seismic loading, than that observed only under unidirectional ground motion. To predict the seismic response of R/C structure with fair accuracy demands, a faithful model that can incorporate the effect of biaxial bending interaction in column. This model should not have high computational demand but should adequately reflect the stiffness degrading and strength deterioration characteristics of R/C structural members. Present study is an effort to develop such a bi-directional hysteresis model accounting the effect of interaction between lateral loadings in two orthogonal directions. The development of the present model is based on the yield surface approach and it can incorporate both strength and stiffness degradation characteristics, which is unavoidable in R/C structures during cyclic loading. The performance of the proposed model/ is demonstrated through the prediction of available experimental results of a reinforced concrete column, subjected to biaxial loading. (author)

  2. Pattern zoology in biaxially pre-stretched elastic bilayers: from wrinkles and creases to fracture-like ridges

    Science.gov (United States)

    Al-Rashed, Rashed; Lopez JiméNez, Francisco; Reis, Pedro

    The wrinkling of elastic bilayers under compression has been explored as a method to produce reversible surface topography, with applications ranging from microfluidics to tunable optics. We introduce a new experimental system to study the effects of pre-stretching on the instability patterns that result from the biaxial compression of thin shells bound to an elastic substrate. A pre-stretched substrate is first prepared by pressurizing an initially flat elastomeric disk and bulging it into a nearly hemispherical thick shell. The substrate is then coated with a thin layer of a polymer suspension, which, upon curing, results in a thin shell of nearly constant thickness. Releasing the pre-stretch in the substrate by deflating the system places the outer film in a state of biaxial compression, resulting in a variety of buckling patterns. We explore the parameter space by systematically varying the pre-stretch, the substrate/film stiffness mismatch, and the thickness of the film. This results in a continuous transition between different buckling patterns, from the dimples and wrinkles that are traditionally associated with the buckling of elastic bilayers, to creases and high aspect ratio `fracture-like' ridges, where the pre-stretch plays an essential role.

  3. Determination of the Quality and Shelf Life of Sous Vide Cooked Turkey Cutlet Stored at 4 and 12ºC

    Directory of Open Access Journals (Sweden)

    IT Akoğlu

    Full Text Available ABSTRACT The aim of this study was to determine the quality and shelf life of sous vide turkey cutlet stored at 4 and 12ºC. Samples were packaged under vacuum into polyamide-polypropylene pouches, cooked using sous vide technology (65ºC/40 min, chilled at 3ºC and stored at 4 and 12ºC for 5 weeks. Microbial (TMAB, lactic acid bacteria, Enterobacteriaceae, moulds and yeasts, Salmonella spp., L. monocytogenes, Cl. perfringens, physical-chemical (pH, water activity, TBARS, L*a*b* colour, texture profile analysis and shear force and sensory (appearance, colour, odour, flavour, juiciness, chewiness and acceptance parameters were determined. According to the results of mesophilic bacterial counts and sensory analysis, the shelf life of the sous vide turkey cutlet, cooked at 65ºC for 40 min, was determined as 28 days at 4ºC while 15 days at 12ºC. Salmonella spp., L. monocytogenes, Cl. perfringens were not detected in turkey cutlet samples during the storage period. It was detected that sous vide cooked provided convenient ready-to-eat foods and a long shelf life for turkey cutlet.

  4. Change in physical and chemical characteristics related to the binomial time-temperature used in sous pasteurization see Tambaqui (Colossoma macropomum

    Directory of Open Access Journals (Sweden)

    H.C.A. Kato

    2016-02-01

    Full Text Available The goal of this study was to evaluate sous vide fish and assess the influence of time and temperature on the pasteurization process through quality parameters. The raw material (tambaqui fillets and the sous vide underwent physical, physicochemical, and microbiological analyses. A sauce was prepared containing soy sauce, water, horseradish and garlic flakes. The product's pasteurization parameters of time and temperature were defined according to a 22 central composite rotatable design (CCRD, and the dependent variables were water holding capacity (WHC and instrumental texture aiming at obtaining high WHC values for the product to maintain the desired juiciness. The microbiological analysis required by legislation have indicated that the fish fillets and sous vide were within de standard. The values of total coliforms found in the samples (fillets and sous vide analyzed were below the critical level of 10² CFU/g. The counts of sulphite-reducing clostridia and psychrotrophic and mesophilic bacteria on plates in the samples were <1x10 CFU/g. In conclusion, temperature was the most important factor in the pasteurization process, significantly contributing to the quality of the final product. The mathematical models proposed were considered predictive for each response.

  5. Biaxial and antiferroelectric structure of the orthogonal smectic phase of a bent-shaped molecule and helical structure in a chiral mixture system

    Science.gov (United States)

    Kang, Sungmin; Nguyen, Ha; Nakajima, Shunpei; Tokita, Masatoshi; Watanabe, Junji

    2013-05-01

    We examined the biaxial and antiferroelectric properties in the Smectic-APA (Sm-APA) phase of bent-shaped DC-S-8. The biaxiality, which results from the existence of a secondary director, was well established from birefringence observations in the homeotropically aligned Sm-APA. By entering into Sm-APA phase, the birefringence (Δn, difference between two refractive indices of short axes) continuously increased from 0 to 0.02 with decreasing temperature. The antiferroelectric switching and second harmonic generation (SHG) activity on the field-on state were also observed in the Sm-APA phase, and the evaluated spontaneous polarization (PS) value strongly depended on temperature. The temperature dependence of Δn and PS resembles each other and follows Haller's approximation, showing that the biaxiality is due to polar packing in which the molecules are preferentially packed with their bent direction arranged in the same direction, and that the phase transition of Sm-APA to Sm-A is second order. The biaxiality was further examined in chiral Sm-APA*. Doping with chiral components induced the helical twisting of the secondary director in the Sm-APA* phase, which was confirmed by observing the reflection of the circular dichroism (CD) bands in the homeotropically aligned cell. The helical pitch of Sm-APA* is tunable in the range of 300-700 nm wavelength with a variation in the chiral content of 5 to 10 weight (wt)%.

  6. Most effective way to improve the hydrogen storage abilities of Na-decorated BN sheets: applying external biaxial strain and an electric field.

    Science.gov (United States)

    Tang, Chunmei; Zhang, Xue; Zhou, Xiaofeng

    2017-02-15

    Density functional calculations were used to investigate the hydrogen storage abilities of Na-atoms-decorated BN sheets under both external biaxial strain and a vertical electric field. The Na atom generally has the weakest binding strength to a given substrate compared with the other elements in the periodic table [PANS, 2016, 113, 3735]. Consequently, it is understudied in comparison to other elements and there are few reports about the hydrogen storage abilities of Na-decorated nanomaterials. We calculated that the average binding energy (E b ) of Na atoms to the pure BN sheet is 1.08 eV, which is smaller than the cohesive energy of bulk Na (1.11 eV). However, the E b can be increased to 1.15 eV under 15% biaxial strain, and further up to 1.53 eV with the control of both 15% biaxial strain and a 5.14 V nm -1 electric field (E-field). Therefore, the application of biaxial strain and an external upward E-field can prevent clustering of the Na atoms on the surface of a BN sheet, which is crucial for the hydrogen storage. Each Na atom on the surface of a BN sheet can adsorb only one H 2 molecule when no strain or E-field is applied; however, the absorption increases to five H 2 molecules under 15% biaxial strain and six H 2 molecules under both 15% biaxial strain combined with a 5.14 V nm -1 E-field. The average adsorption energies for H 2 of BN-(Na-mH 2 ) (m = 1-6) are within the range of practical applications (0.2-0.6 eV). The hydrogen gravimetric density of the periodic BN-(Na-6H 2 ) 4 structure is 9 wt%, which exceeds the 5.5 wt% value that should be met by 2017 as specified by the US Department of Energy. On the other side, removal of the biaxial strain and E-field can help to desorb the H 2 molecule. These findings suggest a new route to design hydrogen storage materials under near-ambient conditions.

  7. Biaxial analysis of synthetic scaffolds for hernia repair demonstrates variability in mechanical anisotropy, non-linearity and hysteresis.

    Science.gov (United States)

    Deeken, Corey R; Thompson, Dominic M; Castile, Ryan M; Lake, Spencer P

    2014-10-01

    Over the past 60 years, the soft tissue repair market has grown to include over 50 types of hernia repair materials. Surgeons typically implant these materials in the orientation that provides maximum overlap of the mesh over the defect, with little regard for mechanical properties of the mesh material. If the characteristics of the meshes were better understood, an appropriate material could be identified for each patient, and meshes could be placed to optimize integration with neighboring tissue and avoid the mechanical mis-match that can lead to impaired graft fixation. The purpose of this study was to fully characterize and compare the mechanical properties of thirteen types of hernia repair materials via planar biaxial tensile testing. Equibiaxial (i.e., equal simultaneous loading in both directions) and strip biaxial (i.e., loading in one direction with the other direction held fixed) tests were utilized as physiologically relevant loading regimes. After applying a 0.1N pre-load on each arm, samples were subjected to equibiaxial cyclic loading using a triangular waveform to 2.5mm displacement on each arm at 0.1Hz for 10 cycles. Samples were then subjected to two strip biaxial tests (using the same cyclic loading protocol), where extension was applied along a single axis with the other axis held fixed. The thirteen evaluated mesh types exhibited a wide range of mechanical properties. Some were nearly isotropic (C-QUR™, DUALMESH(®), PHYSIOMESH™, and PROCEED(®)), while others were highly anisotropic (Ventralight™ ST, Bard™ Mesh, and Bard™ Soft Mesh). Some displayed nearly linear behavior (Bard™ Mesh), while others were non-linear with a long toe region followed by a sharp rise in tension (INFINIT(®)). These materials are currently utilized in clinical settings as if they are uniform and interchangeable, and clearly this is not the case. The mechanical properties most advantageous for successful hernia repairs are currently only vaguely described

  8. Influence of Citric Acid on the Pink Color and Characteristics of Sous Vide Processed Chicken Breasts During Chill Storage

    Science.gov (United States)

    Lim, Ki-Won

    2015-01-01

    Chicken breast dipped with citric acid (CA) was treated by sous vide processing and stored in a refrigerated state for 0, 3, 6, 9, and 14 d. A non-dipped control group (CON) and three groups dipped in different concentrations of citric acid concentration were analyzed (0.5%, 0.5CIT; 2.0%, 2CIT and 5.0%, 5CIT; w/v). Cooking yield and moisture content increased due to the citric acid. While the redness of the juice and meat in all groups showed significant increase during storage, the redness of the citric acid groups was reduced compared to the control group (pacid reactive substances (TBARS) were generally lower in the citric acid-treated samples than in untreated ones, indicating extended shelf life of the cooked chicken breast dipped in citric acid solution. The shear force of the 2CIT and 5CIT groups was significantly lower (pcitric acid concentrations. PMID:26761885

  9. Effect of different temperature-time combinations on lipid and protein oxidation of sous-vide cooked lamb loins.

    Science.gov (United States)

    Roldan, Mar; Antequera, Teresa; Armenteros, Monica; Ruiz, Jorge

    2014-04-15

    Forty-five lamb loins were subjected to sous-vide cooking at different combinations of temperature (60, 70 and 80 °C) and time (6, 12 and 24 h) to assess the effect on the oxidative stability of lipids and proteins. Heating induced both lipid and protein oxidation in lamb loins. Higher cooking temperature-time combinations increased conjugated dienes and decreased thiobarbituric reactive substances (TBARS) values and hexanal. Total protein carbonyls increased throughout time at all cooking temperatures considered, while α-aminoadipic (AAS) and γ-glutamic semialdehydes (GGS) increased when cooking at 60 °C but not at 80 °C. Links between the decrease in secondary compounds from lipid oxidation due to cooking at higher temperatures and for longer times with the increased levels of 3-methylbutanal and greater differences between total protein carbonyls and AAS plus GGS were hypothesised. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Les images en géographie sous l’angledes humanités numériques

    Directory of Open Access Journals (Sweden)

    Gaëlle Hallair

    2009-04-01

    Full Text Available L’article présente une méthodologie pour conserver, stocker, inventorier, archiver, numériser, indexer, valoriser et diffuser des archives géographiques sous l’angle des Digital humanities. L’article applique cette méthodologie aux images en géographie avant de présenter un projet de plate-forme documentaire concernant les plaques de verres du fonds Emmanuel de Martonne hébergées actuellement par l’UMR CNRS 8586 PRODIG.This article points out the methodology of Digital humanities to preserve, to stock, to make an inventory, to digitize, to index, to enhance the value und to spread geographical archives. It applies this methodology to geographical visual documents and presents a database project about photographic plates of the Emmanuel de Martonne’s collection localised in the research center PRODIG (UMR CNRS 8586.

  11. Lille, place financière intermédiaire sous la Révolution et l’Empire

    OpenAIRE

    De Oliveira, Matthieu

    2011-01-01

    Dernière grande place négociante et financière avant la frontière septentrionale, Lille joue pleinement son rôle d’intermédiaire entre les marchés parisiens au Sud et belgo-hollandais au Nord sous la Révolution et l’Empire. La déclaration de guerre en 1792 puis la départementalisation des territoires conquis ne font que renforcer la position nodale des acteurs économiques et financiers de la place. Au premier rang d’entre eux, François Briansiaux mobilise efficacement son important réseau de ...

  12. Effects of Interphase Modification and Biaxial Orientation on Dielectric Properties of Poly(ethylene terephthalate)/Poly(vinylidene fluoride-co-hexafluoropropylene) Multilayer Films.

    Science.gov (United States)

    Yin, Kezhen; Zhou, Zheng; Schuele, Donald E; Wolak, Mason; Zhu, Lei; Baer, Eric

    2016-06-01

    Recently, poly(vinylidene fluoride) (PVDF)-based multilayer films have demonstrated enhanced dielectric properties, combining high energy density and high dielectric breakdown strength from the component polymers. In this work, further enhanced dielectric properties were achieved through interface/interphase modulation and biaxial orientation for the poly(ethylene terephthalate)/poly(methyl methacrylate)/poly(vinylidene fluoride-co-hexafluoropropylene) [PET/PMMA/P(VDF-HFP)] three-component multilayer films. Because PMMA is miscible with P(VDF-HFP) and compatible with PET, the interfacial adhesion between PET and P(VDF-HFP) layers should be improved. Biaxial stretching of the as-extruded multilayer films induced formation of highly oriented fibrillar crystals in both P(VDF-HFP) and PET, resulting in improved dielectric properties with respect to the unstretched films. First, the parallel orientation of PVDF crystals reduced the dielectric loss from the αc relaxation in α crystals. Second, biaxial stretching constrained the amorphous phase in P(VDF-HFP) and thus the migrational loss from impurity ions was reduced. Third, biaxial stretching induced a significant amount of rigid amorphous phase in PET, further enhancing the breakdown strength of multilayer films. Due to the synergistic effects of improved interfacial adhesion and biaxial orientation, the PET/PMMA/P(VDF-HFP) 65-layer films with 8 vol % PMMA exhibited optimal dielectric properties with an energy density of 17.4 J/cm(3) at breakdown and the lowest dielectric loss. These three-component multilayer films are promising for future high-energy-density film capacitor applications.

  13. Evaluation of anisotropic effective stress-strain criteria for the biaxial yield and flow of 2024 aluminum tubes

    International Nuclear Information System (INIS)

    Stout, M.G.; Hecker, S.S.; Bourcier, R.

    1983-01-01

    2024 aluminum tubes, heat treated to a T6 and T8 temper, were tested in combinations of tension-internal pressure and tension-torsion loading. Yield loci and flow behavior were determined for both modes of loading and compared to theoretical predictions. Both tempers of 2024 aluminum exhibited crystallographic textures and anisotropic yield and flow. Hill's quadratic yield criterion and the associated flow rule under-estimate balanced biaxial yield and flow, which is consistent with hydraulic bulge data on other face-centered cubic metals. Hill's nonquadratic criterion, which adds one additional parameter, and Bassani's criterion, which adds two parameters, predict the anisotropic yield behavior much more accurately. Predictions of the complete flow behavior, including strain paths, with these anisotropic criteria could be improved markedly by including provisions for planar anisotropy

  14. Self-field ac losses in biaxially aligned Y endash Ba endash Cu endash O tape conductors

    International Nuclear Information System (INIS)

    Iijima, Y.; Hosaka, M.; Sadakata, N.; Saitoh, T.; Kohno, O.; Takeda, K.

    1997-01-01

    Self-field ac losses were measured by the conventional ac four-probe method in biaxially aligned Y endash Ba endash Cu endash O tapes using polycrystalline Hastelloy tapes with textured yttria-stabilized-zirconia buffer layers. The ac losses increased in proportion to the fourth power of transport current in the high J c sample, and agreed well with Norris close-quote equation for thin strip conductors. However, the low J c sample had rather higher losses than Norris close-quote prediction, suggesting excessive magnetic flux penetration caused by percolated current paths. The results confirmed Norris close-quote prediction of the low ac losses for thin strip conductors, and indicated the importance of removing percolated structures of current paths to avoid higher ac losses than the theoretical predictions based on uniform conductors. copyright 1997 American Institute of Physics

  15. Core structure and dynamics of non-Abelian vortices in a biaxial nematic spinor Bose-Einstein condensate

    Science.gov (United States)

    Borgh, Magnus O.; Ruostekoski, Janne

    2016-05-01

    We demonstrate that multiple interaction-dependent defect core structures as well as dynamics of non-Abelian vortices can be realized in the biaxial nematic (BN) phase of a spin-2 atomic Bose-Einstein condensate (BEC). An experimentally simple protocol may be used to break degeneracy with the uniaxial nematic phase. We show that a discrete spin-space symmetry in the core may be reflected in a breaking of its spatial symmetry. The discrete symmetry of the BN order parameter leads to non-commuting vortex charges. We numerically simulate reconnection of non-Abelian vortices, demonstrating formation of the obligatory rung vortex. In addition to atomic BECs, non-Abelian vortices are theorized in, e.g., liquid crystals and cosmic strings. Our results suggest the BN spin-2 BEC as a prime candidate for their realization. We acknowledge financial support from the EPSRC.

  16. Biaxial Mechanical Evaluation of Absorbable and Nonabsorbable Synthetic Surgical Meshes Used for Hernia Repair: Physiological Loads Modify Anisotropy Response.

    Science.gov (United States)

    Cordero, A; Hernández-Gascón, B; Pascual, G; Bellón, J M; Calvo, B; Peña, E

    2016-07-01

    The aim of this study was to obtain information about the mechanical properties of six meshes commonly used for hernia repair (Surgipro(®), Optilene(®), Infinit(®), DynaMesh(®), Ultrapro™ and TIGR(®)) by planar biaxial tests. Stress-stretch behavior and equibiaxial stiffness were evaluated, and the anisotropy was determined by testing. In particular, equibiaxial test (equal simultaneous loading in both directions) and biaxial test (half of the load in one direction following the Laplace law) were selected as a representation of physiologically relevant loads. The majority of the meshes displayed values in the range of 8 and 18 (N/mm) in each direction for equibiaxial stiffness (tangent modulus under equibiaxial load state in both directions), while a few achieved 28 and 50 (N/mm) (Infinit (®) and TIGR (®)). Only the Surgipro (®) mesh exhibited planar isotropy, with similar mechanical properties regardless of the direction of loading, and an anisotropy ratio of 1.18. Optilene (®), DynaMesh (®), Ultrapro (®) and TIGR (®) exhibited moderate anisotropy with ratios of 1.82, 1.84, 2.17 and 1.47, respectively. The Infinit (®) scaffold exhibited very high anisotropy with a ratio of 3.37. These trends in material anisotropic response changed during the physiological state in the human abdominal wall, i.e. T:0.5T test, which the meshes were loaded in one direction with half the load used in the other direction. The Surgipro (®) mesh increased its anisotropic response (Anis[Formula: see text] = 0.478) and the materials that demonstrated moderate and high anisotropic responses during multiaxial testing presented a quasi-isotropic response, especially the Infinit(®) mesh that decreased its anisotropic response from 3.369 to 1.292.

  17. An analytical model for the ductile failure of biaxially loaded type 316 stainless steel subjected to thermal transients

    International Nuclear Information System (INIS)

    Dimelfi, R.J.

    1987-01-01

    Failure properties are calculated for the case of biaxially loaded type 316 stainless steel tubes that are heated from 300 K to near melting at various constant rates. The procedure involves combining a steady state plastic-deformation rate law with a strain hardening equation. Integrating under the condition of plastic instability gives the time and plastic strain at which ductile failure occurs for a given load. The result is presented as an analytical expression for equivalent plastic strain as a function of equivalent stress, temperature, heating rate and material constants. At large initial load, ductile fracture is calculated to occur early, at low temperatures, after very little deformation. At very small loads deformation continues for a long time to high temperatures where creep rupture mechanisms limit ductility. In the case of intermediate loads, the plastic strain accumulated before the occurrence of unstable ductile fracture is calculated. Comparison of calculated results is made with existing experimental data from pressurized tubes heated at 5.6 K/s and 111 K/s. When the effect of grain growth on creep ductility is taken into account from recrystallization data, agreement between measured and calculated uniform ductility is excellent. The general reduction in ductility and failure time that is observed at higher heating rate is explained via the model. The model provides an analytical expression for the ductility and failure time during transients for biaxially loaded type 316 stainless steel as a function of the initial temperature and load, as well as the material creep and strain hardening parameters. (orig.)

  18. The impact of hydrofluoric acid etching followed by unfilled resin on the biaxial strength of a glass-ceramic.

    Science.gov (United States)

    Posritong, Sumana; Borges, Alexandre Luiz Souto; Chu, Tien-Min Gabriel; Eckert, George J; Bottino, Marco A; Bottino, Marco C

    2013-11-01

    To evaluate the null hypotheses that hydrofluoric (HF) acid etching time would neither decrease the biaxial flexural strength of a glass-based veneering ceramic nor enhance it after silane and unfilled resin (UR) applications. Disc-shaped IPS e.max ZirPress specimens were allocated into 12 groups: G1-control (no-etching), G2-30 s, G3-60 s, G4-90 s, G5-120 s, G6-60 s+60 s. Groups (G7-G12) were treated in the same fashion as G1-G6, but followed by silane and UR applications. Surface morphology and roughness (Ra and Rq) of the ceramics were assessed by means of scanning electron microscopy (SEM) and profilometry, respectively. Flexural strength was determined by biaxial testing. Data were analyzed by two-way ANOVA and the Sidak test (α=0.05). Weibull statistics were estimated and finite element analysis (FEA) was carried out to verify the stress concentration end areas of fracture. The interaction (etching time vs. surface treatment) was significant for Ra (p=0.008) and Rq (0.0075). Resin-treated groups presented significantly lower Ra and Rq than non-treated groups, except for the 60s group (pceramic microstructure and that the UR was able to penetrate into the irregularities. A significant effect of etching time (p=0.029) on flexural strength was seen. G7-G12 presented higher strength than G1-G6 (pceramic flexural strength. Moreover, the flexural strength could be enhanced after UR treatment. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  19. Behaviour of uranium under irradiation; Comportement de l'uranium sous irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Adda, Y; Mustelier, J P; Quere, Y [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-07-01

    phase alloys (U Nb, U Mo) the size and distribution of the bubbles are greatly influenced by the existence of a polygonization lattice, formed before irradiation, inside the grains. During high temperature annealings the bubbles situated on the polygonization lattice grow much faster than those which are distributed inside the crystal. In the case of uranium the bubbles are either distributed at random, or grouped in flat accumulations which can give rise to transgranular cracks, according to the state of the metal and the irradiation temperature. At high temperature an intergranular de-cohesion is also observed. (authors) [French] On expose les principaux resultats obtenus dans l'etude de la formation des defauts introduits dans l'uranium par la fission a basse temperature. Par irradiation a 20 K on a pu evaluer le nombre de paires de Frenkel produites par une fission. L'analyse des courbes de variation de resistivite electrique a permis de preciser l'etendue des pointes de deplacement (deplacement Spike) et le mecanisme de la creation des defauts dus a la fission. Des irradiations a 77 K ont apporte des precisions supplementaires et indiquent un comportement different de l'uranium recristallise et ecroui. On a etudie la diffusion des gaz rares a partir d'alliages metal-gaz rare obtenus par decharge electrique et d'echantillons d'uranium irradie. Le degagement des gaz rares sous vide n'est controle par un processus de diffusion simple que dans le cas ou la teneur en gaz rare est tres faible (U tres faiblement irradie). Par contre quand la teneur en gaz rare est plus forte (echantillons prepares par decharge electrique) le degagement du gaz se produit par formation, croissance et coalescence de bulles; le coefficient de diffusion apparent est alors tres different du coefficient vrai et ne peut etre utilise dans les calculs de gonflement. Dans le cas d'un processus de diffusion simple on a etudie les differents facteurs qui regissent le phenomene. On a montre en

  20. Utilisation des sous-produits agroalimentaires dans l’alimentation des poissons d’élevage en Côte d’Ivoire

    Directory of Open Access Journals (Sweden)

    Kimou Nestor B.

    2016-03-01

    Full Text Available Cette étude évalue l’impact de l’utilisation des sous-produits agroalimentaires dans l’alimentation des poissons d’élevage en Côte d’Ivoire. Une enquête a été réalisée en 2013 dans quinze principales zones piscicoles sur les caractéristiques technico-économiques des fermes, le profil socio-économique des promoteurs et les pratiques aquacoles, particulièrement l’alimentation des poissons. Les résultats révèlent que 71 % des pisciculteurs enquêtés utilisent des sous-produits agricoles durant au moins un stade de production. Parmi eux, 53 % utilisent exclusivement des sous-produits. Le son de riz (52 % et le mélange de sons de riz et de maïs (28 % sont les plus utilisés. Les prix moyens de ces sous-produits varient entre 20 et 105 FCFA/kg. Oreochromis niloticus et Heterotis niloticus sont les principales espèces élevées en polyculture sur les fermes. Les sous-produits sont utilisés en système semi-intensif, extensif et en rizipisciculture, en majorité en zone rurale. Les pisciculteurs sont pour la plupart des agriculteurs, âgés de plus de 40 ans. Les taux d’utilisation des sous-produits sont plus élevés dans les régions de l’Ouest, du Centre-Ouest et du Sud-Ouest de la Côte d’Ivoire, par rapport à celles du Sud et de l’Est. Les rendements des fermes sont relativement faibles (544 à 2445 kg/ha/an, avec des gains moyens quotidiens de 0,87 et 9,97 g/j pour le tilapia et l’heterotis respectivement. L’analyse des stratégies des acteurs suggère la nécessité de définir des mécanismes d’accompagnement et de financement de la pisciculture, afin que ces acteurs puissent améliorer les formulations alimentaires à partir des matières premières locales et accessibles.

  1. Effect of the cooking method (grilling, roasting, frying and sous-vide) on the oxidation of thiols, tryptophan, alkaline amino acids and protein cross-linking in jerky chicken

    OpenAIRE

    Silva, Fábio A. P.; Ferreira, Valquíria C. S.; Madruga, Marta S.; Estévez, Mario

    2016-01-01

    Broiler breast (pectoralis major) meat was submitted to salting with NaCl + NaNO3 followed by a drying process to produce jerky-type chicken. The final product (raw broiler charqui) was desalted and then cooked using grilled, roasted, fried and sous-vide techniques. Sous-vide cooked samples showed lowest results of moisture loss compared to roasted and fried ones. Fatty acid profile suffered minor changes after cooking of broiler charqui. Regarding to protein oxidation, tryptophan fluorescenc...

  2. PH measurement under pressure and at high temperatures; Mesure du pH sous pression et a temperature elevee

    Energy Technology Data Exchange (ETDEWEB)

    Fournie, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Le Peintre, M; Mahieu, C [Centre National de la Recherche Scientifique (CNRS), 91 - Gif-sur-Yvette (France)

    1961-07-01

    In the first part the development and operation of a glass electrode under pressure at room temperature is described. The pressure equilibrium between the inside and outside of the glass membrane several centimetres thick is obtained instantaneously by means of a siphon. The use of a silicone oil as electrical insulator makes possible the working of the glass electrode with the siphon at high pressures (100 kg/cm{sup 2}). In the second part, we determined the pH of various buffer solutions up to 250 deg. C using a cell of our design having two hydrogen electrodes. The values thus obtained for the buffer solutions make it possible to verify and calibrate the pH electrodes independently of the oxido-reduction potential of the medium. In the third part we give the results obtained up to 200 deg. C with the glass electrodes developed in conjunction with the Societe St Gobain. (author) [French] Dans une premiere partie, nous exposons la mise au point et le fonctionnement d'une electrode en verre sous pression a la temperature ordinaire. L'equilibrage instantane de la pression a l'interieur et a l'exterieur de la membrane en verre de quelques diziemes de millimetres d'epaisseur s'effectue par l'intermediaire d'un siphon. L'emploi d'une huile de silicone comme isolant electrique a permis le fonctionnement de l'electrode en verre a siphon sous haute pression (1000 kg/cm{sup 2}). Dans une deuxieme partie, nous avons determine jusqu'a 250 deg. C les valeurs du pH des diverses solutions tampons avec une cellule de notre conception a deux electrodes d'hydrogene. Les valeurs des solutions tampons ainsi obtenues permettent de verifier et d'etalonner les electrodes a pH independantes du potentiel d'oxydo-reduction du milieu. Dans une troisieme partie, nous relatons les resultats obtenus jusqu'a 200 deg. C avec les electrodes en verre mis au point en collaboration avec la Societe Saint-Gobain. (auteur)

  3. Measurements for uranium-light water subcritical assembly; Mesures pour ensemble sous-critique uranium-eau legere d'enseignement

    Energy Technology Data Exchange (ETDEWEB)

    Barre, J Y [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1964-07-01

    The aim of this report is to determine the matter Laplacian of a subcritical assembly, done for educational purposes, using natural uranium combustible and light water for the moderator and the reflector. (M.B.) [French] L'objet de ce rapport est la determination du Laplacien matiere d'un reseau sous-critique, destine a l'enseignement, utilisant comme combustible l'uranium naturel et comme moderateur et reflecteur l'eau naturelle. (M.B.)

  4. Effect of biaxial strain and external electric field on electronic properties of MoS{sub 2} monolayer: A first-principle study

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Chuong V., E-mail: chuongnguyen11@gmail.com [Institute of Research and Development, Duy Tan University, Da Nang (Viet Nam); School of Mechanical Engineering, Le Quy Don Technical University, Ha Noi (Viet Nam); Hieu, Nguyen N. [Institute of Research and Development, Duy Tan University, Da Nang (Viet Nam)

    2016-04-01

    In this work, making use of density functional theory (DFT) computations, we systematically investigate the effect of biaxial strain engineering and external electric field applied perpendicular to the layers on the band gaps and electronic properties of monolayer MoS{sub 2}. The direct-to-indirect band gaps and semiconductor-to-metal transition are observed in monolayer MoS{sub 2} when strain and electric field are applied in our calculation. We show that when the biaxial strain and external electric field are introduced, the electronic properties including band gaps of monolayer MoS{sub 2} can be reduced to zero. Our results provide many useful insights for the wide applications of monolayer MoS{sub 2} in electronics and optoelectronics.

  5. Shear Piezoelectricity in Poly(vinylidenefluoride-co-trifluoroethylene): Full Piezotensor Coefficients by Molecular Modeling, Biaxial Transverse Response, and Use in Suspended Energy-Harvesting Nanostructures.

    Science.gov (United States)

    Persano, Luana; Catellani, Alessandra; Dagdeviren, Canan; Ma, Yinji; Guo, Xiaogang; Huang, Yonggang; Calzolari, Arrigo; Pisignano, Dario

    2016-09-01

    The intrinsic flexible character of polymeric materials causes remarkable strain deformations along directions perpendicular to the applied stress. The biaxial response in the shear piezoelectricity of polyvinylidenefluoride copolymers is analyzed and their full piezoelectric tensors are provided. The microscopic shear is exploited in single suspended nanowires bent by localized loading to couple flexural deformation and transverse piezoelectric response. © 2016 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Biaxial mechanics and inter-lamellar shearing of stem-cell seeded electrospun angle-ply laminates for annulus fibrosus tissue engineering.

    Science.gov (United States)

    Driscoll, Tristan P; Nakasone, Ryan H; Szczesny, Spencer E; Elliott, Dawn M; Mauck, Robert L

    2013-06-01

    The annulus fibrosus (AF) of the intervertebral disk plays a critical role in vertebral load transmission that is heavily dependent on the microscale structure and composition of the tissue. With degeneration, both structure and composition are compromised, resulting in a loss of AF mechanical function. Numerous tissue engineering strategies have addressed the issue of AF degeneration, but few have focused on recapitulation of AF microstructure and function. One approach that allows for generation of engineered AF with appropriate (+/-)30° lamellar microstructure is the use of aligned electrospun scaffolds seeded with mesenchymal stem cells (MSCs) and assembled into angle-ply laminates (APL). Previous work indicates that opposing lamellar orientation is necessary for development of near native uniaxial tensile properties. However, most native AF tensile loads are applied biaxially, as the disk is subjected to multi-axial loads and is constrained by its attachments to the vertebral bodies. Thus, the objective of this study was to evaluate the biaxial mechanical response of engineered AF bilayers, and to determine the importance of opposing lamellar structure under this loading regime. Opposing bilayers, which replicate native AF structure, showed a significantly higher modulus in both testing directions compared to parallel bilayers, and reached ∼60% of native AF biaxial properties. Associated with this increase in biaxial properties, significantly less shear, and significantly higher stretch in the fiber direction, was observed. These results provide additional insight into native tissue structure-function relationships, as well as new benchmarks for engineering functional AF tissue constructs. Copyright © 2013 Orthopaedic Research Society.

  7. The Evaluation of the Effect of Strain Limits on the Physical Properties of Magnetorheological Elastomers Subjected to Uniaxial and Biaxial Cyclic Testing.

    OpenAIRE

    Gorman, Dave; Murphy, Niall; Ekins, Ray; Jerrams, Stephen

    2017-01-01

    Magnetorheological Elastomers (MREs) are “smart” materials whose physical properties are altered by the application of magnetic fields. In a previous study by the authors [1], variations in the physical properties of MREs have been evaluated when subjected to a range of magnetic field strengths for both uniaxial and biaxial cyclic tests. By applying the same magnetic field to similar samples, this paper investigates the effect of both the upper strain limit and the strain amplitude on the pro...

  8. Stick-slip behavior of Indian gabbro as studied using a NIED large-scale biaxial friction apparatus

    Science.gov (United States)

    Togo, Tetsuhiro; Shimamoto, Toshihiko; Yamashita, Futoshi; Fukuyama, Eiichi; Mizoguchi, Kazuo; Urata, Yumi

    2015-04-01

    This paper reports stick-slip behaviors of Indian gabbro as studied using a new large-scale biaxial friction apparatus, built in the National Research Institute for Earth Science and Disaster Prevention (NIED), Tsukuba, Japan. The apparatus consists of the existing shaking table as the shear-loading device up to 3,600 kN, the main frame for holding two large rectangular prismatic specimens with a sliding area of 0.75 m2 and for applying normal stresses σ n up to 1.33 MPa, and a reaction force unit holding the stationary specimen to the ground. The shaking table can produce loading rates v up to 1.0 m/s, accelerations up to 9.4 m/s2, and displacements d up to 0.44 m, using four servocontrolled actuators. We report results from eight preliminary experiments conducted with room humidity on the same gabbro specimens at v = 0.1-100 mm/s and σ n = 0.66-1.33 MPa, and with d of about 0.39 m. The peak and steady-state friction coefficients were about 0.8 and 0.6, respectively, consistent with the Byerlee friction. The axial force drop or shear stress drop during an abrupt slip is linearly proportional to the amount of displacement, and the slope of this relationship determines the stiffness of the apparatus as 1.15 × 108 N/m or 153 MPa/m for the specimens we used. This low stiffness makes fault motion very unstable and the overshooting of shear stress to a negative value was recognized in some violent stick-slip events. An abrupt slip occurred in a constant rise time of 16-18 ms despite wide variation of the stress drop, and an average velocity during an abrupt slip is linearly proportional to the stress drop. The use of a large-scale shaking table has a great potential in increasing the slip rate and total displacement in biaxial friction experiments with large specimens.

  9. Fatigue behavior of boxing welded joint under biaxial cyclic loads; 2juku kurikaeshi kajuka ni okeru kakumawashi yosetsu keishu no hiro kyodo

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, I.; Takada, A.; Akiyama, S.; Ushijima, M.; Maenaka, H. [Ministry of Transportation, Tokyo (Japan)

    1998-12-31

    Various forces such as gravity, wave induced force, inertial force etc. compositely act on a ship body from various directions. Therefore, while discussing strength or life of structural elements of ship body, it is necessary to understand the effects of the composite force condition. In this study, fatigue tests of boxing welded joint under rectangular biaxial cyclic loads are performed, the following results are obtained. Even under he biaxial cyclic loads, it is the same as the uniaxial test, the cracks occurred at the boxing weld toes propagate almost in the straight y-direction, but no oblique propagation of the cracks caused by the lad in the y-direction occurs. That the crack at initial stage of the crack progress is improved in y-direction can be illustrated by the facts that the residual stress in x-direction near the toes reaches to the yield stress, and the stress concentration in the welded toes is bigger in x-direction than that in y-direction. But as for prediction of the progress route, a further study including amplitude ratio of the biaxial loads, effects of width of test specimen is necessary. 4 refs., 12 figs., 4 tabs.

  10. Microfracture pattern compared to core-scale fractures in the borehole of Soultz-sous-Forets granite, Rhine graben, France

    Energy Technology Data Exchange (ETDEWEB)

    Dezayes, C.; Villemin, T. [Universite de Savoie (France). Laboratoire de Geodynamique des Chaines Alpines, UPRES-A CNRS 5025; Pecher, A. [Universite Joseph Fourier, Grenoble (France). Laboratoire de Geodynamique des Chaines Alpines, UPRES-A CNRS 5025

    2000-07-01

    Microfractures appearing in thin section as fluid inclusion trails in quartz crystals were studied in four core samples of Soultz-sous-Forets granite. Their orientations in four series of three mutually perpendicular thin sections were estimated using a previously described apparent dip method and a new method involving measurements of strike and apparent dips. Three samples display three microfracture sets and one sample displays two sets. In all samples, one set is nearly vertical and strikes N-S. In two samples, one and two sets are nearly vertical and strike E-W. In two samples, two sets strike NW-SE: one is vertical, the other dips gently to the NE (or SW). Comparing microfracture and mesofractures sets in the same cores shows that (1) the N-S microfacture set is always dominant at both scales and (2) all other microfracture sets have no mesoscopic counterpart. The N-S microfracture sets could have been created during E-W extension of earliest Cenozoic age (Rhine Graben rifting). Differences between the two scales are explained by a {sigma}{sub 1}/{sigma}{sub 2} switching which occurred at the crystal scale and generated mutually perpendicular cracks.

  11. Studies and support for the EGS reservoirs at Soultz-sous-Forets. April 2004 - May 2009. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Portier, S.; Vuataz, F.-D. [Centre de Recherche en Geothermie (CREGE), Neuchatel (Switzerland)

    2009-08-15

    This comprehensive final report for the Swiss Federal Office of Energy (SFOE) takes a look at the activities carried out during the period from April 2004 up to May 2009 at Soultz-sous-Forets, France, in connection with the enhanced geothermal systems (EGS) at that location. The report describes the work performed by the Swiss EGS Research and Development group involved in the Soultz project. The principal target set was to install and operate a power plant, enabling the deep reservoir/heat exchanger to be operated, evaluated and improved under realistic conditions. The Swiss contributors have been participating in several work packages: Short and long term tests and medium-term tests of the three-well reservoir/heat exchanger system, development and up-scaling, technical and economic design of larger, industrial, EGS units and the development of stimulation methodology for EGS. The exchange of findings obtained during this project phase is discussed, as is the state-of-the-art of EGS stimulation methods, the interpretation of logging data. Also, seismic /-hydraulic factors, the evaluation of the production/injection performance of the boreholes and reservoir development strategies are discussed as are the modelling of geochemical impact of forced fluid circulation in the deep geothermal reservoir and the results of chemical stimulation tests performed on site.

  12. Efficacy of Combined Sous Vide-Microwave Cooking for Foodborne Pathogen Inactivation in Ready-to-Eat Chicory Stems.

    Science.gov (United States)

    Renna, Massimiliano; Gonnella, Maria; de Candia, Silvia; Serio, Francesco; Baruzzi, Federico

    2017-07-01

    There is a variety of different food processing methods, which can be used to prepare ready-to-eat foods. However, the need to preserve the freshness and nutritional qualities leads to the application of mild technologies which may be insufficient to inactivate microbial pathogens. In this work, fresh chicory stems were packed under a vacuum in films, which were transparent to microwaves. These were then exposed to microwaves for different periods of time. The application of sous vide microwave cooking (SV-MW, 900 W, 2450 MHz), controlled naturally occurring mesophilic aerobic bacteria, yeasts and molds for up to 30 d when vacuum-packed vegetables were stored at 4 °C. In addition, the process lethality of the SV-MW 90 s cooking was experimentally validated. This treatment led to 6.07 ± 0.7 and 4.92 ± 0.65 log cfu/g reduction of Escherichia coli and Listeria monocytogenes inoculated over the chicory stems (100 g), respectively. With an initial load of 9 log cfu/g for both pathogens, less than 10 cfu/g of surviving cells were found after 90 s cooking. This shows that short-time microwave cooking can be used to effectively pasteurize vacuum-packed chicory stems, achieving >5 log cfu/g reduction of E. coli and L. monocytogenes. © 2017 Institute of Food Technologists®.

  13. Spatiotemporal complexity of 2-D rupture nucleation process observed by direct monitoring during large-scale biaxial rock friction experiments

    Science.gov (United States)

    Fukuyama, Eiichi; Tsuchida, Kotoyo; Kawakata, Hironori; Yamashita, Futoshi; Mizoguchi, Kazuo; Xu, Shiqing

    2018-05-01

    We were able to successfully capture rupture nucleation processes on a 2-D fault surface during large-scale biaxial friction experiments using metagabbro rock specimens. Several rupture nucleation patterns have been detected by a strain gauge array embedded inside the rock specimens as well as by that installed along the edge walls of the fault. In most cases, the unstable rupture started just after the rupture front touched both ends of the rock specimen (i.e., when rupture front extended to the entire width of the fault). In some cases, rupture initiated at multiple locations and the rupture fronts coalesced to generate unstable ruptures, which could only be detected from the observation inside the rock specimen. Therefore, we need to carefully examine the 2-D nucleation process of the rupture especially when analyzing the data measured only outside the rock specimen. At least the measurements should be done at both sides of the fault to identify the asymmetric rupture propagation on the fault surface, although this is not perfect yet. In the present experiment, we observed three typical types of the 2-D rupture propagation patterns, two of which were initiated at a single location either close to the fault edge or inside the fault. This initiation could be accelerated by the free surface effect at the fault edge. The third one was initiated at multiple locations and had a rupture coalescence at the middle of the fault. These geometrically complicated rupture initiation patterns are important for understanding the earthquake nucleation process in nature.

  14. Fabrication of High Current YBa2Cu3O7-y Coated Conductors Using Rolling-Assisted Biaxially Textured Substrates

    International Nuclear Information System (INIS)

    Christen, D.K.; Feenstra, R.; Kroeger, D.M.; Lee, D.F.; List, F.A.; Martin, P.M.; Norton, D.P.; Paranthaman, M.; Park, C.; Royal, A.; Specht, E.D.; Verebelyi, D.T.

    1999-01-01

    High critical current YBa 2 Cu 3 O 7-y (referred to as YBCO) coated conductors were fabricated with a layer sequence of YBCO/YSZ/CeO 2 /Ni. The cube (100) texture in the starting Ni substrates was obtained by cold rolling followed by recrystallization. A thin CeO 2 (Cerium Oxide) layer with a thickness of 100-200 was grown epitaxially on the biaxially textured-Ni substrates using an e-beam evaporation technique. This was followed by the growth of a thick ( 2 film had a dense microstructure. The microstructure of the e-beam YSZ film was porous whereas the sputtered YSZ film was dense. The YBCO films were grown by pulsed laser deposition on both e-beam and sputtered YSZ layers. A transport critical current density of 1 x l0 6 A/cm 2 at 77 K was obtained for 0.8 m thick YBCO Rims on both YSZ surfaces in zero field. To demonstrate the quality and compatibility of the e-beam CeO 2 layers; YBCO films were also grown on CeO 2 -buffered YSZ (100) single crystal substrates using e-beam co-evaporated Y-BaF 2 -Cu precursors followed by a post-annealing process. A transport critical current density of over 1 x lO 6 A/cm 2 at 77 K was obtained on a 0.3 m thick YBCO film in zero field

  15. Finite element analysis of the biaxial cyclic tensile loading of the elastoplastic plate with the central hole: asymptotic regimes

    Science.gov (United States)

    Turkova, Vera; Stepanova, Larisa

    2018-03-01

    For elastistoplastic structure elements under cyclic loading three types of asymptotic behavior are well known: shakedown, cyclic plasticity or ratcheting. In structure elements operating in real conditions ratcheting must always be excluded since it caused the incremental fracture of structure by means of the accumulation of plastic strains. In the present study results of finite-element (FEM) calculations of the asymptotical behavior of an elastoplastic plate with the central circular and elliptic holes under the biaxial cyclic loading for three different materials are presented. Incremental cyclic loading of the sample with stress concentrator (the central hole) is performed in the multifunctional finite-element package SIMULIA Abaqus. The ranges of loads found for shakedown, cyclic plasticity and ratcheting are presented. The results obtained are generalized and analyzed. Convenient normalization is suggested. The chosen normalization allows us to present all computed results, corresponding to separate materials, within one common curve with minimum scattering of the points. Convenience of the generalized diagram consists in a possibility to find an asymptotical behavior of an inelastic structure for materials for which computer calculations were not made.

  16. Strain mapping near a triple junction in strained Ni-based alloy using EBSD and biaxial nanogauges

    Energy Technology Data Exchange (ETDEWEB)

    Clair, A. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS, Universite de Bourgogne, 9 Avenue Alain Savary, BP 47870, 21078 Dijon Cedex (France); Foucault, M.; Calonne, O. [Areva ANP, Centre Technique Departement Corrosion-Chimie, 30 Bd de l' industrie, BP 181, 71205 Le Creusot (France); Lacroute, Y.; Markey, L.; Salazar, M.; Vignal, V. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS, Universite de Bourgogne, 9 Avenue Alain Savary, BP 47870, 21078 Dijon Cedex (France); Finot, E., E-mail: Eric.Finot@u-bourgogne.fr [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS, Universite de Bourgogne, 9 Avenue Alain Savary, BP 47870, 21078 Dijon Cedex (France)

    2011-05-15

    Research highlights: > Surface strains measured using nanogauge were compared to the texture obtained by EBSD. > Statistics of the principal strain discern the grains according to the Schmid factor. > Strain hotspots were localized near a triple junction of alloy 600 under tensile loading. > Asymetrical profile of the GB strains is a criterion for surface cracking initiation. - Abstract: A key element for analyzing the crack initiation in strained polycrystalline alloys is the local quantification of the surface strain distribution according to the grain texture. Using electron backscattered diffraction, the local microstructure was determined to both localize a triple junction and deduce the local Schmid factors. Kernel average misorientation (KAM) was also used to map the areas of defect concentration. The maximum principal strain and the in-plane shear strain were quantified using the biaxial nanogauge. Distortions of the array of nanodots used as spot markers were analyzed near the triple junction. The crystallographic orientation and the surface strain were then investigated both statistically for each grain and locally at the grain boundaries. The superimposition of microstructure and strain maps allows the high strain gradient (reaching 3-fold the applied strain) to be localized at preferential grain boundaries near the triple junction. The Schmid factors and the KAM were compared to the maximum principal strain and the in-plane shear strain respectively. The polycrystalline deformation was attributable first to the rotation of some grains, followed by the elongation of all grains along their preferential activated slip systems.

  17. Tailoring the structural and electronic properties of a graphene-like ZnS monolayer using biaxial strain

    International Nuclear Information System (INIS)

    Behera, Harihar; Mukhopadhyay, Gautam

    2014-01-01

    Our first-principles full-potential density functional theory calculations show that a ZnS monolayer (ML-ZnS), which is predicted to adopt a graphene-like planar honeycomb structure with a direct band gap, undergoes strain-induced modifications in its structure and band gap when subjected to in-plane homogeneous biaxial strain (δ). ML-ZnS gets buckled for compressive strain greater than 0.92% ; the buckling parameter Δ(= 0.00 Å for planar ML-ZnS) linearly increases with increasing compressive strain (Δ = 0.435 Å at δ = −5.25%). A tensile strain of 2.91% turns the direct ML-ZnS band gap into indirect. Within our considered strain values of |δ| < 6%, the band gap shows linearly decreasing (non-linearly increasing as well as decreasing) variation with tensile (compressive) strain. These predictions (based on our calculations with two atoms per unit cell) may be exploited in future for potential applications in strain sensors and other nano-devices such as nano-electromechanical systems and nano-optomechanical systems. (paper)

  18. Effect of grain shape and texture on equi-biaxial creep of stress relieved and recrystallized Zircaloy-4

    International Nuclear Information System (INIS)

    Murty, K.L.; Tanikella, B.V.; Earthman, J.C.

    1994-01-01

    Zirconium alloys are extensively used in various types of fission reactors both light and heavy water types for different applications, examples being thin-walled tubing to clad radioactive fuel, grids, channels in boiling water reactors (BWRs) as well as pressure and calandria tubes in pressurized heavy water reactors (PHWRs). Biaxial creep behaviors of stress relieved and recrystallized thin-walled tubing of Zircaloy-4 are considered under equal hoop and axial stresses by internal pressurization superimposed with axial load. Both hoop and axial strains were monitored and the ratio of the strain rates along the hoop to axial directions is considered to represent the degree of anisotropy. The slightly stronger hoop direction of the recrystallized material became weaker compared to the axial direction following cold work and a stress-relief anneal. Crystallographic texture was considered in terms of x-ray pole figures from which the crystallite orientation distribution functions (CODF) were derived. A crystal plasticity model based on slip on representative systems was combined with the CODF to predict the creep anisotropy. It was found that the textural differences between the recrystallized and stress-relieved material is believed to invoke anisotropic grain boundary sliding leading to stress enhancement in the hoop direction. This stress enhancement is shown to account for the observed differences in creep behavior between the present equiaxed and columnar grain structures

  19. Development of an in-plane biaxial test for forming limit curve (FLC) characterization of metallic sheets

    International Nuclear Information System (INIS)

    Zidane, I; Guines, D; Léotoing, L; Ragneau, E

    2010-01-01

    The main objective of this work is to propose a new experimental device able to give for a single specimen a good prediction of rheological parameters and formability under static and dynamic conditions (for intermediate strain rates). In this paper, we focus on the characterization of sheet metal forming. The proposed device is a servo-hydraulic testing machine provided with four independent dynamic actuators allowing biaxial tensile tests on cruciform specimens. The formability is evaluated thanks to the classical forming limit diagram (FLD), and one of the difficulties of this study was the design of a dedicated specimen for which the necking phenomenon appears in its central zone. If necking is located in the central zone of the specimen, then the speed ratio between the two axes controls the strain path in this zone and a whole forming limit curve can be covered. Such a specimen is proposed through a numerical and experimental validation procedure. A rigorous procedure for the detection of numerical and experimental forming strains is also presented. Finally, an experimental forming limit curve is determined and validated for an aluminium alloy dedicated to the sheet forming processes (AA5086)

  20. Biaxial creep behavior of ribbed GCFR cladding at 6500C in nominally pure helium (99.99%)

    International Nuclear Information System (INIS)

    Yaggee, F.L.; Purohit, A.; Grajek, W.J.; Peoppel, R.B.

    1977-11-01

    Biaxial creep-rupture tests were conducted on 12 prototypic GCFR fuel-cladding specimens at 650 0 C and a nominal hoop stress of 241.3 MPa. All test specimens were fabricated from 20% cold-worked Type 316 stainless steel tubes that were ribbed on the outer surface by mechanical grinding or electro-chemical etching. Test variables included specimen length and the presence or absence of weld-reinforcing end collars. Test results have indicated that, compared with data on smooth specimens, ribbing has no detrimental effect on creep-rupture lifetime. Specimens fabricated from tubes ribbed by electrochemical etching exhibit a significantly shorter creep-rupture lifetime and a higher secondary (steady-state) creep rate than specimens fabricated from tubes ribbed by mechanical grinding. Specimen length does not strongly affect creep-rupture lifetime, but the presence of an end collar does exhibit a significant influence on both the axial strain profile and the ratio of maximum diametral strain at the failure site to average diametral strain away from the failure site. The ribs do not inhibit the propagation of fissure or rupture failures

  1. Field-induced optically isotropic state in bent core nematic liquid crystals: unambiguous proof of field-induced optical biaxiality

    International Nuclear Information System (INIS)

    Elamain, Omaima; Komitov, Lachezar; Hegde, Gurumurthy; Fodor-Csorba, Katalin

    2013-01-01

    The behaviour of bent core (BC) nematic liquid crystals was investigated under dc applied electric field. The optically isotropic state of a sample containing BC nematic was observed under application of low dc electric fields. The quality of the dark state when the sample was inserted between two crossed polarizers was found to be superb and it did not change when rotating the sample between the polarizers. The coupling between the net molecular dipole moment and the applied dc electric field was considered as the origin of the out-of-plane switching of the BC molecules resulting in switching from the field-off bright state to the field-on dark state. The field-induced optically isotropic state is an unambiguous proof of the field-induced biaxiality in the BC nematic liquid crystal. A simple model explaining the appearance of the isotropic optical state in BC nematics and the switching of the sample slow axis between three mutually orthogonal directions under dc applied electric field is proposed. (paper)

  2. An isotropic suspension system for a biaxial accelerometer using electroplated thick metal with a HAR SU-8 mold

    International Nuclear Information System (INIS)

    Lee, Jin Seung; Lee, Seung S

    2008-01-01

    In this paper, a novel approach is developed to design an isotropic suspension system using thick metal freestanding micro-structures combining bulk micro-machining with electroplating based on a HAR SU-8 mold. An omega-shape isotropic suspension system composed of circular curved beams that have free switching of imaginary boundary conditions is proposed. This novel isotropic suspension design is not affected by geometric dimensional parameters and always achieves matching stiffness along the principle axes of elasticity. Using the finite element method, the isotropic suspension system was compared with an S-shaped meandering suspension system. In order to realize the suggested isotropic suspension system, a cost-effective fabrication process using electroplating with the SU-8 mold was developed to avoid expensive equipment and materials such as deep reactive-ion etching (DRIE) or a silicon-on-insulator (SOI) wafer. The fabricated isotropic suspension system was verified by electromagnetic actuation experiments. Finally, a biaxial accelerometer with isotropic suspension system was realized and tested using a vibration generator system. The proposed isotropic suspension system and the modified surface micro-machining technique based on electroplating with an SU-8 mold can contribute towards minimizing the system size, simplifying the system configuration, reducing the system price of and facilitating mass production of various types of low-cost sensors and actuators

  3. Interference of wedge-shaped protrusions on the faces of a Griffith crack in biaxial stress. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Boulet, J.A.M. [Tennessee Univ., Knoxville, TN (United States)

    1992-04-01

    An initial investigation of the influence of protrusion interference on the fracture toughness required to prevent unstable propagation of a Griffith crack in a brittle material is described. The interference is caused by relative shear displacement of the crack faces when subjected to remote biaxial stress with neither principal stress parallel to the crack. It is shown that for room temperature cracks smaller than about one centimeter in silicon carbide, or about one millimeter in silicon nitride, the presence of interference changes the fracture stress. A mathematical model based on linear elasticity solutions and including multiple interference sites at arbitrarily specified positions on the crack is presented. Computations of the change in required fracture toughness and its dependence on wedge geometry (size and vertex angle), applied stresses (orientation and magnitude), and location of the interference site are discussed. Results indicate that a single interference site has only a slight effect on required toughness. However, the influence of interference increases monotonically with the number of interference sites. The two-dimensional model described herein is not accurate when the interference sites are closely spaced.

  4. Monitoring Poisson’s Ratio Degradation of FRP Composites under Fatigue Loading Using Biaxially Embedded FBG Sensors

    Science.gov (United States)

    Akay, Erdem; Yilmaz, Cagatay; Kocaman, Esat S.; Turkmen, Halit S.; Yildiz, Mehmet

    2016-01-01

    The significance of strain measurement is obvious for the analysis of Fiber-Reinforced Polymer (FRP) composites. Conventional strain measurement methods are sufficient for static testing in general. Nevertheless, if the requirements exceed the capabilities of these conventional methods, more sophisticated techniques are necessary to obtain strain data. Fiber Bragg Grating (FBG) sensors have many advantages for strain measurement over conventional ones. Thus, the present paper suggests a novel method for biaxial strain measurement using embedded FBG sensors during the fatigue testing of FRP composites. Poisson’s ratio and its reduction were monitored for each cyclic loading by using embedded FBG sensors for a given specimen and correlated with the fatigue stages determined based on the variations of the applied fatigue loading and temperature due to the autogenous heating to predict an oncoming failure of the continuous fiber-reinforced epoxy matrix composite specimens under fatigue loading. The results show that FBG sensor technology has a remarkable potential for monitoring the evolution of Poisson’s ratio on a cycle-by-cycle basis, which can reliably be used towards tracking the fatigue stages of composite for structural health monitoring purposes. PMID:28773901

  5. A nonlocal continuum model for the biaxial buckling analysis of composite nanoplates with shape memory alloy nanowires

    Science.gov (United States)

    Farajpour, M. R.; Shahidi, A. R.; Farajpour, A.

    2018-03-01

    In this study, the buckling behavior of a three-layered composite nanoplate reinforced with shape memory alloy (SMA) nanowires is examined. Whereas the upper and lower layers are reinforced with typical nanowires, SMA nanoscale wires are used to strengthen the middle layer of the system. The composite nanoplate is assumed to be under the action of biaxial compressive loading. A scale-dependent mathematical model is presented with the consideration of size effects within the context of the Eringen’s nonlocal continuum mechanics. Using the one-dimensional Brinson’s theory and the Kirchhoff theory of plates, the governing partial differential equations of SMA nanowire-reinforced hybrid nanoplates are derived. Both lateral and longitudinal deflections are taken into consideration in the theoretical formulation and method of solution. In order to reduce the governing differential equations to their corresponding algebraic equations, a discretization approach based on the differential quadrature method is employed. The critical buckling loads of the hybrid nanosystem with various boundary conditions are obtained with the use of a standard eigenvalue solver. It is found that the stability response of SMA composite nanoplates is strongly sensitive to the small scale effect.

  6. Biaxial Properties of the Left and Right Pulmonary Arteries in a Monocrotaline Rat Animal Model of Pulmonary Arterial Hypertension.

    Science.gov (United States)

    Pursell, Erica R; Vélez-Rendón, Daniela; Valdez-Jasso, Daniela

    2016-11-01

    In a monocrotaline (MCT) induced-pulmonary arterial hypertension (PAH) rat animal model, the dynamic stress-strain relation was investigated in the circumferential and axial directions using a linear elastic response model within the quasi-linear viscoelasticity theory framework. Right and left pulmonary arterial segments (RPA and LPA) were mechanically tested in a tubular biaxial device at the early stage (1 week post-MCT treatment) and at the advanced stage of the disease (4 weeks post-MCT treatment). The vessels were tested circumferentially at the in vivo axial length with matching in vivo measured pressure ranges. Subsequently, the vessels were tested axially at the mean pulmonary arterial pressure by stretching them from in vivo plus 5% of their length. Parameter estimation showed that the LPA and RPA remodel at different rates: axially, both vessels decreased in Young's modulus at the early stage of the disease, and increased at the advanced disease stage. Circumferentially, the Young's modulus increased in advanced PAH, but it was only significant in the RPA. The damping properties also changed in PAH; in the LPA relaxation times decreased continuously as the disease progressed, while in the RPA they initially increased and then decreased. Our modeling efforts were corroborated by the restructuring organization of the fibers imaged under multiphoton microscopy, where the collagen fibers become strongly aligned to the 45 deg angle in the RPA from an uncrimped and randomly organized state. Additionally, collagen content increased almost 10% in the RPA from the placebo to advanced PAH.

  7. Biaxial creep behavior of ribbed GCFR cladding at 650/sup 0/C in nominally pure helium (99. 99%)

    Energy Technology Data Exchange (ETDEWEB)

    Yaggee, F. L.; Purohit, A.; Grajek, W. J.; Peoppel, R. B.

    1977-11-01

    Biaxial creep-rupture tests were conducted on 12 prototypic GCFR fuel-cladding specimens at 650/sup 0/C and a nominal hoop stress of 241.3 MPa. All test specimens were fabricated from 20% cold-worked Type 316 stainless steel tubes that were ribbed on the outer surface by mechanical grinding or electro-chemical etching. Test variables included specimen length and the presence or absence of weld-reinforcing end collars. Test results have indicated that, compared with data on smooth specimens, ribbing has no detrimental effect on creep-rupture lifetime. Specimens fabricated from tubes ribbed by electrochemical etching exhibit a significantly shorter creep-rupture lifetime and a higher secondary (steady-state) creep rate than specimens fabricated from tubes ribbed by mechanical grinding. Specimen length does not strongly affect creep-rupture lifetime, but the presence of an end collar does exhibit a significant influence on both the axial strain profile and the ratio of maximum diametral strain at the failure site to average diametral strain away from the failure site. The ribs do not inhibit the propagation of fissure or rupture failures.

  8. Above-bandgap optical properties of biaxially strained GeSn alloys grown by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Richard D’Costa, Vijay, E-mail: elevrd@nus.edu.sg; Wang, Wei; Zhou, Qian; Yeo, Yee-Chia, E-mail: eleyeoyc@nus.edu.sg [Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583 (Singapore); Soon Tok, Eng [Department of Physics, National University of Singapore, Singapore 117551 (Singapore)

    2014-01-13

    The complex dielectric function of biaxially strained Ge{sub 1−x}Sn{sub x} (0 ≤ x ≤ 0.17) alloys grown on Ge (100) has been determined by spectroscopic ellipsometry from 1.2 to 4.7 eV. The effect of substitutional Sn incorporation and the epitaxial strain on the energy transitions E{sub 1}, E{sub 1} + Δ{sub 1}, E{sub 0}′, and E{sub 2} of GeSn alloys is investigated. Our results indicate that the strained GeSn alloys show Ge-like electronic bandstructure with all the transitions shifted downward due to the alloying of Sn. The strain dependence of E{sub 1} and E{sub 1} + Δ{sub 1} transitions is explained using the deformation potential theory, and values of −5.4 ± 0.4 eV and 3.8 ± 0.5 eV are obtained for the hydrostatic and shear deformation potentials, respectively.

  9. Effect of Ceramic Surface Treatments After Machine Grinding on the Biaxial Flexural Strength of Different CAD/CAM Dental Ceramics.

    Science.gov (United States)

    Bagheri, Hossein; Hooshmand, Tabassom; Aghajani, Farzaneh

    2015-09-01

    This study aimed to evaluate the effect of different ceramic surface treatments after machining grinding on the biaxial flexural strength (BFS) of machinable dental ceramics with different crystalline phases. Disk-shape specimens (10mm in diameter and 1.3mm in thickness) of machinable ceramic cores (two silica-based and one zirconia-based ceramics) were prepared. Each type of the ceramic surfaces was then randomly treated (n=15) with different treatments as follows: 1) machined finish as control, 2) machined finish and sandblasting with alumina, and 3) machined finish and hydrofluoric acid etching for the leucite and lithium disilicate-based ceramics, and for the zirconia; 1) machined finish and post-sintered as control, 2) machined finish, post-sintered, and sandblasting, and 3) machined finish, post-sintered, and Nd;YAG laser irradiation. The BFS were measured in a universal testing machine. Data based were analyzed by ANOVA and Tukey's multiple comparisons post-hoc test (α=0.05). The mean BFS of machined finish only surfaces for leucite ceramic was significantly higher than that of sandblasted (P=0.001) and acid etched surfaces (P=0.005). A significantly lower BFS was found after sandblasting for lithium disilicate compared with that of other groups (Pceramics was affected by the type of ceramic material and surface treatment method. Sandblasting with alumina was detrimental to the strength of only silica-based ceramics. Nd:YAG laser irradiation may lead to substantial strength degradation of zirconia.

  10. Evaluation of biaxial flexural strength and modulus of filled and unfilled adhesive systems = Avaliação da resistência flexural biaxial e módulo de flexão de sistemas adesivos

    Directory of Open Access Journals (Sweden)

    Liberti, Michele Santana

    2009-01-01

    Full Text Available Objetivo: O objetivo deste estudo foi avaliar a resistência flexural e o módulo de flexão de dois sistemas adesivos, através de ensaio de resistência flexural biaxial. Metodologia: Os adesivos (Pentron Clinical Technologies estudados foram: Bond 1 (B1 e NanoBond (NB. Treze discos de cada adesivo foram preparados com dimensões aproximadas de 6,1 mm de diâmetro e 0,6 mm de espessura. Os discos de adesivos foram confeccionados utilizando-se moldes de teflon e fotopolimerizados com aparelho XL 3000 (3M ESPE. Após armazenamento por 10 dias, os discos foram testados em máquina universal de ensaio (Instron 5844, com velocidade de 1,27 mm/min. Os dados foram submetidos à análise de variância (1 fator ao nível de significância de 0,05. Resultados: Os valores médios (±DP de resistência flexural para os adesivos foram (em MPa: B1- 89,7±7,6 e NB- 131,1±9,5. Os valores médios de módulo flexural (±DP foram (em MPa: B1- 1999,9±258,4 e NB- 2314,5±271,0. Conclusão: O adesivo contendo partículas de carga (NB mostrou maiores valores de resistência flexural e módulo de flexão que o adesivo B1

  11. Effets Seebeck et Nernst dans les cuprates: Etude de la reconstruction de la surface de Fermi sous champ magnetique intense

    Science.gov (United States)

    Laliberte, Francis

    2010-06-01

    Ce memoire presente des mesures de transport thermoelectrique, les effets Seebeck et Nernst, dans une serie d'echantillons de supraconducteurs a haute temperature critique. Des resultats obtenus recemment au Laboratoire National des Champs Magnetiques Intenses a Grenoble sur La1.7Eu0.2Sr0.1 CuO4, La1.675Eu0.2Sr0.125CuO 4, La1.64Eu0.2Sr0.16CuO4, La1.74Eu0.1Sr0.16CuO4 et La 1.4Nd0.4Sr0.2CuO4 sont analyses. Une attention particuliere est accordee aux equations de la theorie semi-classique du transport et leur validite est verifiee. La procedure experimentale et les materiaux utilises pour concevoir les montages de mesures sont expliques en detail. Enfin, un chapitre est dedie a l'explication et l'interpretation des resultats de transport thermoelectrique sur YBa2Cu3O6+delta publies au cours de l'hiver 2010 dans les revues Nature et Physical Review Letters. Les donnees d'effet Seebeck dans les echantillons de La 1.8-x,Eu0.2SrxCuO 4, ou un changement de signe est observe, permettent de conclure a la presence d'une poche d'electrons dans la surface de Fermi qui domine le transport a basse temperature dans la region sous-dopee du diagramme de phase. Cette conclusion est similaire a celle obtenue par des mesures d'effet Hall dans YBa 2Cu3O6+delta et elle cadre bien dans un scenario de reconstruction de la surface de Fermi. Les donnees d'effet Nernst recueillies indiquent que la contribution des fluctuations supraconductrices est limitee a un modeste intervalle de temperature au-dessus de la temperature critique.

  12. Construction and Operation of a Commercial Gamma-Ray Package-Sterilizing Plant; Construction et fonctionnement d'une installation industrielle pour la sterilisation d'articles sous emballage par les rayons gamma; Razrabotka i ehkspluatatsiya sbornoj ustanovki gamma-izlucheniya promyshlennogo tipa dlya sterilizatsii meditsinskikh materialov; Construccion y funcionamiento de una instalacion industrial para la esterilizacion gamma de articulos medicos empaquetados

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, C. G. [Johnson' s Ethical Plastics Ltd., Slough (United Kingdom)

    1963-11-15

    The purpose of the paper is to describe the Co{sup 60} sterilizing plant now being operated commercially by Johnson's Ethical Plastics Limited, at Slough, England. This is a continuous process plant with a source of 72000 c and completely automatic operation. Based on experience gained by U.K.A.E.A. in their Package Irradiation Plant at Wantage, the present plant was designed specifically for sterilization of disposable plastic syringes and other medical products of similar bulk density. The plant has been in operation since November 1962. A description is given of the main features of its construction, including personnel safety devices, and method of loading the source rods. Operating experience is described including dosimetry, integration of the plant into a commercial undertaking as a production process, and bacteriological results. A short discussion on the economics of sterilizing by gamma radiation is given and an assessment of possible future applications of a plant of this type. (author) [French] Le memoire est consacre a la description de l'installation de sterilisation au cobalt-60, actuellement exploitee industriellement par la Johnson Ethical Plastics Ltd., a Slough (Angleterre). Cette installation, equipee d'une source de 72 000 c, fonctionne en continu et toutes les operations y sont automatiques. Fondee sur l'experience acquise par l'Autorite de l'energie atomique du Royaume-Uni dans son installation d'irradiation d'articles sous emballage, de Wantage, l'installation decrite est specialement destinee a la sterilisation de seringues en matieres plastiques et d'autres instruments medicaux non recuperables de densite apparente analogue. L'installation est en service depuis novembre 1962. Le memoire decrit ses principales caracteristiques, y compris les appareils de protection du personnel et les dispositifs de chargement des barreaux utilises comme sources. L'auteur fournit des donnees d'ordre pratique, notamment sur la dosimetrie, l'integration de l

  13. Effect of furnace type and ceramming heat treatment conditions on the biaxial flexural strength of a canasite glass-ceramic.

    Science.gov (United States)

    Johnson, A; Shareef, M Y; van Noort, R; Walsh, J M

    2000-07-01

    To assess the effect of different heat treatment conditions when using two different furnace types on the biaxial flexural strength (BFS) of a fluorcanasite castable glass-ceramic. Two furnace types, one a programmable furnace (PF), the other a dental laboratory burnout furnace (DLF), were used with various ceramming times to determine their effect on the BFS of a fluorcanasite castable glass-ceramic. The glass-ceramic material was cast to produce discs of 12 mm diameter and 2 mm thickness using the lost wax casting process (n = 80). After casting, both furnace types were used to ceram the discs. Half the discs were not de-vested from the casting ring before ceramming but cerammed in situ (DLF) and half were de-vested before ceramming (PF). All the discs were given a nucleation heat treatment at 520 degrees C for 1 h and then cerammed at 860 degrees C using four heat soak times (0.5, 1, 2 and 3 h). The DLF furnace had a rate of climb of 13 degrees C/min and the PF furnace had a rate of climb of 5 degrees C/min to 520 degrees C and 3 degrees C/min to 860 degrees C. After ceramming the discs were de-vested and the BFS determined using a Lloyd 2000R tester. The maximum BFS values seen for both furnace types were almost identical (280 MPa), but were achieved at different heat soak times (1 h DLF, and 2 h PF). The only significant differences in BFS values for the two furnaces were between the 0.5 and 2 h heat soak times (p < or = 0.05). Individual differences were seen between results obtained from each furnace type/heat soak times evaluated (p < or = 0.05). Already available dental laboratory burnout furnaces can be used to ceram fluorcanasite glass-ceramic castings to the same BFS values as more expensive and slower specialist programmable furnaces.

  14. Ductile Tearing of Thin Aluminum Plates Under Blast Loading. Predictions with Fully Coupled Models and Biaxial Material Response Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Corona, Edmundo [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gullerud, Arne S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Haulenbeek, Kimberly K. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Reu, Phillip L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-06-01

    The work presented in this report concerns the response and failure of thin 2024- T3 aluminum alloy circular plates to a blast load produced by the detonation of a nearby spherical charge. The plates were fully clamped around the circumference and the explosive charge was located centrally with respect to the plate. The principal objective was to conduct a numerical model validation study by comparing the results of predictions to experimental measurements of plate deformation and failure for charges with masses in the vicinity of the threshold between no tearing and tearing of the plates. Stereo digital image correlation data was acquired for all tests to measure the deflection and strains in the plates. The size of the virtual strain gage in the measurements, however, was relatively large, so the strain measurements have to be interpreted accordingly as lower bounds of the actual strains in the plate and of the severity of the strain gradients. A fully coupled interaction model between the blast and the deflection of the structure was considered. The results of the validation exercise indicated that the model predicted the deflection of the plates reasonably accurately as well as the distribution of strain on the plate. The estimation of the threshold charge based on a critical value of equivalent plastic strain measured in a bulge test, however, was not accurate. This in spite of efforts to determine the failure strain of the aluminum sheet under biaxial stress conditions. Further work is needed to be able to predict plate tearing with some degree of confidence. Given the current technology, at least one test under the actual blast conditions where the plate tears is needed to calibrate the value of equivalent plastic strain when failure occurs in the numerical model. Once that has been determined, the question of the explosive mass value at the threshold could be addressed with more confidence.

  15. Effect of Alumina Addition to Zirconia Nano-composite on Low Temperature Degradation Process and Biaxial Strength

    Directory of Open Access Journals (Sweden)

    Moluk Aivazi

    2016-12-01

    Full Text Available Ceramic dental materials have been considered as alternatives to metals for dental implants application. In this respect, zirconia tetragonal stabilized with %3 yttrium, is of great importance among the ceramic materials for endosseous dental implant application. Because of its good mechanical properties and color similar to tooth. The aim and novelty of this study was to design and prepare Y-TZP nano-composite to reduce the degradation process at low temperature by alumina addition and maintaining submicron grain sized. Also, flexural strength of nano-composite samples was evaluated. Toward this purpose, alumina-Y-TZP nano-composites containing 0–30 vol% alumina (denoted as A-Y-TZP 0-30 were fabricated using α-alumina and Y-TZP nano-sized by sintering pressure less method. The synthesized samples were characterized using x-ray diffraction, field emission scanning electron microscopy equipped with energy dispersive x-ray spectroscopy techniques. Nano-composite samples with high density (≥96% and grain sized of ≤ 400 nm was obtained by sintering at 1270 °C for 170 min. After low temperature degradation test (LTD, A-Y-TZP20 and A-Y-TZP30 not showed monoclinic phase and the flexural strength in all of samples were higher than A-Y-TZP0. It was concluded that the grains were remained in submicron sized and A-Y-TZP20 and A-Y-TZP30 did not present biaxial strength reduction after LTD test.

  16. Biaxial bending of slender HSC columns and tubes filled with concrete under short- and long-term loads: I Theory

    Directory of Open Access Journals (Sweden)

    Jose A. Rodríguez-Gutiérrez

    2014-05-01

    Full Text Available An analytical method that calculates both the short- and long-term response of slender columns made of high-strength concrete (HSC and tubes filled with concrete with generalized end conditions and subjected to transverse loads along the span and axial load at the ends (causing a single or double curvature under uniaxial or biaxial bending is presented. The proposed method, which is an extension of a method previously developed by the authors, is capable of predicting not only the complete load-rotation and load-deflection curves (both the ascending and descending parts but also the maximum load capacity. The columns that can be analyzed include solid and hollow (rectangular, circular, oval, C-, T-, L-, or any arbitrary shape cross sections and columns made of circular and rectangular steel tubes filled with HSC. The fiber method is used to calculate the moment-curvature diagrams at different levels of the applied axial load (i.e., the M-P-φ curves, and the Gauss method of integration (for the sum of the contributions of the fibers parallel to the neutral axis is used to calculate the lateral rotations and deflections along the column span. Long-term effects, such as creep and shrinkage of the concrete, are also included. However, the effects of the shear deformations and torsion along the member are not included. The validity of the proposed method is presented in a companion paper and compared against the experimental results for over seventy column specimens reported in the technical literature by different researchers.

  17. Biaxial Flexural Strength of High-Viscosity Glass-Ionomer Cements Heat-Cured with an LED Lamp during Setting

    Directory of Open Access Journals (Sweden)

    Gustavo Fabián Molina

    2013-01-01

    Full Text Available Adding heat to glass ionomers during setting might improve mechanical properties. The aim was to compare the biaxial flexural strength (BFS between and within four glass ionomers, by time of exposure to a high-intensity LED light-curing unit. Materials and methods. Samples of Fuji 9 Gold Label, Ketac Molar Easymix, ChemFil Rock, and the EQUIA system were divided into three treatment groups (n=30: without heating (Group 1, heated with LED lamp of 1400 mW/cm2 for 30 s while setting (Group 2, and heated with LED lamp of 1400 mW/cm2 for 60 s while setting (Group 3. Samples were stored for 48 hours in distilled water at 37°C until tested. BFS was tested, using a universal testing machine at a crosshead speed of 1 mm/min. Data were analyzed, using ANOVA test with the Bonferroni correction (α=0.05. Heating the glass-ionomer cements with an LED curing light of 1400 mW/cm2 during setting for 30 s increased the BFS value of all GICs. No statistically significant difference in mean BFS scores was found between the EQUIA system and ChemFil Rock at 30 s and 60 s. The mean BFS value was statistically significantly higher for the EQUIA system and ChemFil Rock than for Fuji 9 Gold Label and Ketac Molar Easymix at all exposure times.

  18. Catastrophic biaxial proximal sesamoid bone fractures in UK Thoroughbred races (1999-2004): horse characteristics and racing history.

    Science.gov (United States)

    Kristoffersen, M; Parkin, T D H; Singer, E R

    2010-07-01

    Catastrophic biaxial proximal sesamoid bone fractures (PSBF) have not yet been described in detail in the UK racing population. To determine the incidence and relative risk (RR) of PSBF in different types of racing in the UK; and to describe horse-level characteristics and racing histories of horses sustaining these injuries. Distal limbs were collected from all racehorses suffering catastrophic fractures during racing at all 59 racecourses in the UK, in a prospective study from February 1999 to December 2004. Post mortem investigation identified the anatomical location and type of fracture. Horse, racing history, race and racecourse details were obtained. Characteristics of the horses that sustained PSBF were described. The incidence and RR of PSBF in the different types of racing in the UK were calculated. Thirty-one horses suffered PSBF during the study period. The incidence of PSBF in all types of race was 0.63 per 10,000 starts (31/494,744). The incidence was highest in flat races on all weather surfaces (1.63 per 10,000 starts: 12/73,467; RR = 4.4 when compared to turf flat racing). Affected horses had an average age of 5.6 years and had started a mean of 28 races at the time of fracture. There is a strong association between type of racing surface and PSBF. Horses competing in flat races on all weather surfaces have an increased risk of PSBF. These fractures appear to happen in experienced horses with several starts, with few fractures occurring within the first season of racing. Further research should focus on identification of underlying pathology of these fractures. Epidemiological studies aimed at the identification of risk factors for PSBF in the UK racing population would require a large number of cases acquired over many years given the relatively low incidence of PSBF.

  19. Nonlocal vibration and biaxial buckling of double-viscoelastic-FGM-nanoplate system with viscoelastic Pasternak medium in between

    Energy Technology Data Exchange (ETDEWEB)

    Liu, J.C. [College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058 (China); Zhang, Y.Q., E-mail: cyqzhang@zju.edu.cn [College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058 (China); State Key Laboratory of Mechanical Structural Strength and Vibration, Xi' an Jiaotong University, Xi' an 710049 (China); Fan, L.F. [College of Architecture and Civil Engineering, Beijing University of Technology, Beijing 100084 (China)

    2017-04-11

    The general equation for transverse vibration of double-viscoelastic-FGM-nanoplate system with viscoelastic Pasternak medium in between and each nanoplate subjected to in-plane edge loads is formulated on the basis of the Eringen's nonlocal elastic theory and the Kelvin model. The factors of the structural damping, medium damping, small size effect, loading ratio, and Winkler modulus and shear modulus of the medium are incorporated in the formulation. Based on the Navier's method, the analytical solutions for vibrational frequency and buckling load of the system with simply supported boundary conditions are obtained. The influences of these factors on vibrational frequency and buckling load of the system are discussed. It is demonstrated that the vibrational frequency of the system for the out-of-phase vibration is dependent upon the structural damping, small size effect and viscoelastic Pasternak medium, whereas the vibrational frequency for the in-phase vibration is independent of the viscoelastic Pasternak medium. While the buckling load of the system for the in-phase buckling case has nothing to do with the viscoelastic Pasternak medium, the buckling load for the out-of-phase case is related to the small size effect, loading ratio and Pasternak medium. - Highlights: • Vibration of double-viscoelastic-FGM-nanoplate system under in-plane edge loads is investigated. • Biaxial buckling of the system with simply supported boundary conditions is analyzed. • Explicit expression for the vibrational frequency and buckling load is obtained. • Impacts of viscoelastic Pasternak medium on vibrational frequency and buckling load are discussed. • Influences of structural damping, small size effect and loading ratio are also considered.

  20. Oxidation of steel heated in CO{sub 2} medium under pressure; Oxydation d'un acier ordinaire chauffe dans le gaz carbonique sous pression

    Energy Technology Data Exchange (ETDEWEB)

    Darras, R.; Leclercq, D.; Bunard, C. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    Behaviour of low-alloyed steels heated in CO{sub 2} medium under pressure is reported. Tests are carried out in the range of erature reached in the CO{sub 2} cooled reactors (vessel, thermal shield, pipes). The observed weight increases are small, even after more than a thousand hours of heating at 350 deg. C, but oxidation curve looks like progressing linearly. Furthermore, the oxide formed under a pressure of 15 kg/cm{sup 2} is undoubtedly more compact and adherent than the one formed under a pressure of 1 kg/cm{sup 2}. Finally, for practical use, CO{sub 2} steel pipes surface has to be sand blast and pickled. A following phosphatizing protects it from atmospheric corrosion during assembling, but these treatments have no influence on the behaviour of these steels heated in CO{sub 2}. (author)Fren. [French] On etudie le comportement d'aciers au carbone faiblement allies, chauffes dans le gaz carbonique sous pression, aux temperatures atteintes dans les reacteurs refroidis par ce gaz (caisson, bouclier thermique, canalisations). Les augmentations de poids observees sont faibles, meme apres plus de 1000 heures de chauffage a 350 deg. C, mais l'oxydation semble se poursuivre lineairement. De plus, l'oxyde forme dans le gaz carbonique sous pression de 15 kg/cm{sup 2} est nettement plus compact et adherent que celui forme sous pression atmospherique de gaz carbonique. Enfin, dans la pratique, les surfaces d'acier du circuit de gaz carbonique sont necessairement sablees ou decapees; une phosphatation ulterieure le protege de la corrosion atmospherique pendant le montage. Ces traitements sont sans influence sur le comportement de ces aciers dans le gaz carbonique a chaud. (auteur)

  1. Oxidation of steel heated in CO{sub 2} medium under pressure; Oxydation d'un acier ordinaire chauffe dans le gaz carbonique sous pression

    Energy Technology Data Exchange (ETDEWEB)

    Darras, R; Leclercq, D; Bunard, C [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    Behaviour of low-alloyed steels heated in CO{sub 2} medium under pressure is reported. Tests are carried out in the range of erature reached in the CO{sub 2} cooled reactors (vessel, thermal shield, pipes). The observed weight increases are small, even after more than a thousand hours of heating at 350 deg. C, but oxidation curve looks like progressing linearly. Furthermore, the oxide formed under a pressure of 15 kg/cm{sup 2} is undoubtedly more compact and adherent than the one formed under a pressure of 1 kg/cm{sup 2}. Finally, for practical use, CO{sub 2} steel pipes surface has to be sand blast and pickled. A following phosphatizing protects it from atmospheric corrosion during assembling, but these treatments have no influence on the behaviour of these steels heated in CO{sub 2}. (author)Fren. [French] On etudie le comportement d'aciers au carbone faiblement allies, chauffes dans le gaz carbonique sous pression, aux temperatures atteintes dans les reacteurs refroidis par ce gaz (caisson, bouclier thermique, canalisations). Les augmentations de poids observees sont faibles, meme apres plus de 1000 heures de chauffage a 350 deg. C, mais l'oxydation semble se poursuivre lineairement. De plus, l'oxyde forme dans le gaz carbonique sous pression de 15 kg/cm{sup 2} est nettement plus compact et adherent que celui forme sous pression atmospherique de gaz carbonique. Enfin, dans la pratique, les surfaces d'acier du circuit de gaz carbonique sont necessairement sablees ou decapees; une phosphatation ulterieure le protege de la corrosion atmospherique pendant le montage. Ces traitements sont sans influence sur le comportement de ces aciers dans le gaz carbonique a chaud. (auteur)

  2. Brigitte SIMONOT et Gabriel GALLEZOT (2009) (dir.), L’entonnoir : Google sous la loupe des sciences de l’information et de la communication

    OpenAIRE

    Bonaccorsi, Julia

    2013-01-01

    Ce titre annonce d’emblée une posture critique et, plus largement, une promesse de dévoilement. L’approche communicationnelle, affirmée dès le sous-titre, saisit Google comme un objet de recherche à construire à distance des discours promotionnels ou pamphlétaires. La recherche collective prend appui sur une perspective sociotechnique, mais également sociopolitique du moteur de recherche et de ses usages, pour interroger la production de valeurs par la société Google. Le moteur est scruté au ...

  3. Measurement and Analysis of Ultra-Thin Austenitic Stainless Steel Sheet under Biaxial Tensile Loading and In-Plane Reverse Loading

    Science.gov (United States)

    Murakoso, Satoko; Kuwabara, Toshihiko

    Biaxial tensile tests of austenitic stainless steel sheet (SUS304) 0.2mm thick have been carried out using cruciform specimens. The specimens are loaded under linear stress paths in a servo-controlled biaxial tensile testing machine. Plastic orthotropy remained coaxial with the principal stresses throughout every experiment. The successive contours of plastic work in biaxial stress space changed their shapes progressively, exemplifying differential work hardening. The geometry of the entire family of the work contours and the directions of plastic strain rates have been precisely measured and compared with those calculated using conventional yield functions. Yld2000-2d [Barlat, F., Brem, J.C., Yoon, J.W., Chung, K., Dick, R.E., Lege, D.J., Pourboghrat, F., Choi, S.H. and Chu, E., International Journal of Plasticity, Vol. 19, (2003), pp. 1297-1319.] with an exponent of 6 was capable of reproducing the general trends of the work contours and the directions of plastic strain rates with good accuracy. Furthermore, in order to quantitatively evaluate the Bauschinger effect of the test material, in-plane tension/compression tests are conducted. It was found that the non-dimensional (σ /σu) - Δɛ /(σu/ E) curves measured during unloading almost fall on a single curve and are not affected by the amount of pre-strain, where σ is the current stress during unloading, σu is the stress immediately before unloading, Δɛ (< 0) is the total strain increment during unloading.

  4. Applicability of a particularly simple model to nonlinear elasticity of slide-ring gels with movable cross-links as revealed by unequal biaxial deformation.

    Science.gov (United States)

    Kondo, Yuuki; Urayama, Kenji; Kidowaki, Masatoshi; Mayumi, Koichi; Takigawa, Toshikazu; Ito, Kohzo

    2014-10-07

    The strain energy density function (F) of the polyrotaxane-based slide-ring (SR) gels with movable cross-links along the network strands is characterized by unequal biaxial stretching which can achieve various types of deformation. The SR gels as prepared without any post-preparation complication exhibit considerably smaller values of the ratio of the stresses (σy/σx) in the stretched (x) and constrained (y) directions in planar extension than classical chemical gels with heterogeneous and nearly homogeneous network structures do. This feature of the SR gels leads to the peculiar characteristic that the strain energy density function (F) has no explicit cross term of strains in different directions, which is in contrast to F with explicit strain cross terms for most chemical gels and elastomers. The biaxial stress-strain data of the SR gels are successfully described by F of the Gent model with only two parameters (small-strain shear modulus and a parameter representing ultimate elongation), which introduces the finite extensibility effect into the neo-Hookean model with no explicit cross term of strain. The biaxial data of the deswollen SR gels examined in previous study, which underwent a considerable reduction in volume from the preparation state, are also well described by the Gent model, which is in contrast to the case of the classical chemical gels that the stress-strain relations before and after large deswelling are not described by a common type of F due to a significant degree of collapse of the network strands in the deswollen state. These intriguing features of nonlinear elasticity of the SR gels originate from a novel function of the slidable cross-links that can maximize the arrangement entropy of cross-linked and non-cross-linked cyclic molecules in the deformed networks.

  5. Effect of the cooking method (grilling, roasting, frying and sous-vide) on the oxidation of thiols, tryptophan, alkaline amino acids and protein cross-linking in jerky chicken.

    Science.gov (United States)

    Silva, Fábio A P; Ferreira, Valquíria C S; Madruga, Marta S; Estévez, Mario

    2016-08-01

    Broiler breast ( pectoralis major ) meat was submitted to salting with NaCl + NaNO 3 followed by a drying process to produce jerky-type chicken. The final product (raw broiler charqui) was desalted and then cooked using grilled, roasted, fried and sous-vide techniques. Sous-vide cooked samples showed lowest results of moisture loss compared to roasted and fried ones. Fatty acid profile suffered minor changes after cooking of broiler charqui. Regarding to protein oxidation, tryptophan fluorescence, protein carbonylation and disulphide bonds formation of chicken charqui were affected by cooking temperature while free thiol groups, Schiff base formation and hardness were mostly impacted by the length of cooking. Instrumental color of broiler charqui was affected by the type of cooking, being closely related with Maillard products formation. In conclusion, sous-vide technique seems to be the most advantageous cooking method to obtain high-quality ready-to-eat chicken charqui.

  6. Bi-axial M-. Phi. analyses of RC columns using fiber model and comparison with experimental results. 2 jikumage wo ukeru hashirabuzai no M-. Phi. kankei eno fiber model no tekigosei

    Energy Technology Data Exchange (ETDEWEB)

    Murayama, Y.; Tokuyama, S.; Furuichi, K. (Kajima Corp., Tokyo (Japan))

    1991-10-31

    In order to examine the accuracy of a fiber model for analyzing the stability of towers of a cable-stayed bridge subjected to biaxial bending force due to earthquake, experimental results of column test specimens were compared with analytical results. The relation between biaxial bending moment and curvature (M-{Phi}) was measured in biaxial bending model experiment using a reinforcement ratio, axial compressive force and loading pattern as parameters. Since the relation was greatly affected by axial modeling of a reinforcing material, the parameter analysis was conducted by paying particular attention to reinforcement models (bilinear model, cubic one and Ramberg-Osgood one). As a result, the Ramberg-Osgood model was suitable for columns with a large longitudinal reinforcement ratio and large axial tension such as seen in highrise buildings, while the cubic model was more suitable for columns with a small ratio such as seen in cable-stayed bridges. 4 refs., 10 figs., 1 tab.

  7. Physicochemical and microbiological changes during the refrigerated storage of lamb loins sous-vide cooked at different combinations of time and temperature.

    Science.gov (United States)

    Roldán, Mar; Antequera, Teresa; Hernández, Alejandro; Ruiz, Jorge

    2015-10-01

    This study aimed to determine the influence of cooking temperature (either 60 ℃ or 80 ℃) and time (6 h or 24 h) on the physicochemical (weight loss, moisture content, instrumental color, instrumental texture, lipid and protein oxidation) and microbiological changes underwent by sous-vide cooked lamb loins during refrigerated storage for 30 days. There was a slight trend to decreasing weight losses in some of the cooking treatments, but only in samples cooked at 60 ℃ for 6 h it was paralleled with an increase in moisture content. The only noteworthy oxidative change was a marked decrease in conjugated dienes after two weeks of storage in samples cooked at 80 ℃ for 24 h. Neither instrumental texture nor color showed noticeable variations during the storage. Microbial population remained quite low during the whole refrigerated storage. Overall, most of the studied parameters showed only scarce changes throughout 30 days of refrigerated storage that most likely would not influence the quality of sous-vide cooked loin lambs. © The Author(s) 2014.

  8. Oxidation of ordinary steels or alloys heated in carbon dioxide under pressure; Oxydation d'aciers ordinaires ou allies chauffes dans le gaz carbonique sous pression

    Energy Technology Data Exchange (ETDEWEB)

    Leclercq, D; Chevilliard, C; Darras, R [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    Selection tests were carried out on commercial steels from the viewpoint of their resistance to oxidation in carbon dioxide, under 25 atmospheres pressure, between 350 and 600 deg. C. Comparative curve of oxidation kinetics were obtained, from which the influence of various additive elements can be found; small amounts of aluminium particularly seem to be favourable in the case of only slightly alloyed steels. (author) [French] Des essais de selection d'aciers commerciaux ont ete effectues quant a leur resistance a l'oxydation dans le gaz carbonique, sous pression de 25 atmospheres, ente 350 et 600 deg. C. Des courbes comparatives de cinetique d'oxydation ont ete obtenues, ce qui permet de degager l'influence de divers elements d'addition; de faibles teneurs en aluminium apparaissent notamment favorables dans le cas des aciers peu allies. L'acier inoxydable 18-8 a egalement ete etudie, notamment sous forme de tubes minces. Son comportement est bon jusqu'au moins 600 deg. C dans ces conditions. (auteur)

  9. Effect of different temperature-time combinations on physicochemical, microbiological, textural and structural features of sous-vide cooked lamb loins.

    Science.gov (United States)

    Roldán, Mar; Antequera, Teresa; Martín, Alberto; Mayoral, Ana Isabel; Ruiz, Jorge

    2013-03-01

    Lamb loins were subjected to sous-vide cooking at different combinations of temperature (60, 70, and 80 °C) and time (6, 12, and 24 h). Different physicochemical, histological and structural parameters were studied. Increasing cooking temperatures led to higher weight losses and lower moisture contents, whereas the effect of cooking time on these variables was limited. Samples cooked at 60 °C showed the highest lightness and redness, while increasing cooking temperature and cooking time produced higher yellowness values. Most textural variables in a texture profile analysis showed a marked interaction between cooking temperature and time. Samples cooked for 24h showed significantly lower values for most of the studied textural parameters for all the temperatures considered. Connective tissue granulation at 60 °C and gelation at 70 °C were observed in the SEM micrographs. The sous-vide cooking of lamb loins dramatically reduced microbial population even with the less intense heat treatment studied (60 °C-6 h). Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Méthode d'estimation des tassements des sols fins sous les remblais d'infrastructures ferroviaires pour lignes à grande vitesse

    Science.gov (United States)

    Said Alami, Soukaina; Reiffsteck, Philippe; Cuira, Fahd

    2018-02-01

    Le besoin de maîtriser les déformations des sols sous les remblais destinés à recevoir les structures de lignes à grande vitesse, en fait un enjeu important pour ces projets. Toutefois, de nombreuses difficultés ont été soulevées liées principalement au grand nombre d'incertitudes qui entourent le phénomène. En effet, la caractérisation géologique et géotechnique dépend de sondages et d'essais où le risque de remaniement est important et dont l'interprétation est, souvent, délicate. Cet article présente une procédure de calcul qui permettrait en pratique d'évaluer le tassement sous remblai avec une bonne précision et qui a été validée sur un certain nombre d'ouvrages. Pour cela, des corrections sont introduites aux méthodes usuelles de calcul permettant d'approcher les valeurs mesurées sur chantier.

  11. Prediction of crack growth direction by Strain Energy Sih's Theory on specimens SEN under tension-compression biaxial loading employing Genetic Algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-MartInez R; Lugo-Gonzalez E; Urriolagoitia-Calderon G; Urriolagoitia-Sosa G; Hernandez-Gomez L H; Romero-Angeles B; Torres-San Miguel Ch, E-mail: rrodriguezm@ipn.mx, E-mail: urrio332@hotmail.com, E-mail: guiurri@hotmail.com, E-mail: luishector56@hotmail.com, E-mail: romerobeatriz98@hotmail.com, E-mail: napor@hotmail.com [INSTITUTO POLITECNICO NACIONAL Seccion de Estudios de Posgrado e Investigacion (SEPI), Escuela Superior de Ingenieria Mecanica y Electrica (ESIME), Edificio 5. 2do Piso, Unidad Profesional Adolfo Lopez Mateos ' Zacatenco' Col. Lindavista, C.P. 07738, Mexico, D.F. (Mexico)

    2011-07-19

    Crack growth direction has been studied in many ways. Particularly Sih's strain energy theory predicts that a fracture under a three-dimensional state of stress spreads in direction of the minimum strain energy density. In this work a study for angle of fracture growth was made, considering a biaxial stress state at the crack tip on SEN specimens. The stress state applied on a tension-compression SEN specimen is biaxial one on crack tip, as it can observed in figure 1. A solution method proposed to obtain a mathematical model considering genetic algorithms, which have demonstrated great capacity for the solution of many engineering problems. From the model given by Sih one can deduce the density of strain energy stored for unit of volume at the crack tip as dW = [1/2E({sigma}{sup 2}{sub x} + {sigma}{sup 2}{sub y}) - {nu}/E({sigma}{sub x}{sigma}{sub y})]dV (1). From equation (1) a mathematical deduction to solve in terms of {theta} of this case was developed employing Genetic Algorithms, where {theta} is a crack propagation direction in plane x-y. Steel and aluminium mechanical properties to modelled specimens were employed, because they are two of materials but used in engineering design. Obtained results show stable zones of fracture propagation but only in a range of applied loading.

  12. Study of lattice strain evolution during biaxial deformation of stainless steel using a finite element and fast Fourier transform based multi-scale approach

    International Nuclear Information System (INIS)

    Upadhyay, M.V.; Van Petegem, S.; Panzner, T.; Lebensohn, R.A.; Van Swygenhoven, H.

    2016-01-01

    A multi-scale elastic-plastic finite element and fast Fourier transform based approach is proposed to study lattice strain evolution during uniaxial and biaxial loading of stainless steel cruciform shaped samples. At the macroscale, finite element simulations capture the complex coupling between applied forces in the arms and gauge stresses induced by the cruciform geometry. The predicted gauge stresses are used as macroscopic boundary conditions to drive a mesoscale elasto-viscoplastic fast Fourier transform model, from which lattice strains are calculated for particular grain families. The calculated lattice strain evolution matches well with experimental values from in-situ neutron diffraction measurements and demonstrates that the spread in lattice strain evolution between different grain families decreases with increasing biaxial stress ratio. During equibiaxial loading, the model reveals that the lattice strain evolution in all grain families, and not just the 311 grain family, is representative of the polycrystalline response. A detailed quantitative analysis of the 200 and 220 grain family reveals that the contribution of elastic and plastic anisotropy to the lattice strain evolution significantly depends on the applied stress ratio.

  13. Distribution and viability of fetal and adult human bone marrow stromal cells in a biaxial rotating vessel bioreactor after seeding on polymeric 3D additive manufactured scaffolds

    Directory of Open Access Journals (Sweden)

    Anne eLeferink

    2015-10-01

    Full Text Available One of the conventional approaches in tissue engineering is the use of scaffolds in combination with cells to obtain mechanically stable tissue constructs in vitro prior to implantation. Additive manufacturing by fused deposition modeling is a widely used technique to produce porous scaffolds with defined pore network, geometry, and therewith defined mechanical properties. Bone marrow derived mesenchymal stromal cells (MSCs are promising candidates for tissue engineering based cell therapies due to their multipotent character. One of the hurdles to overcome when combining additive manufactured scaffolds with MSCs is the resulting heterogeneous cell distribution and limited cell proliferation capacity. In this study, we show that the use of a biaxial rotating bioreactor, after static culture of human fetal MSCs (hfMSCs seeded on synthetic polymeric scaffolds, improved the homogeneity of cell and extracellular matrix (ECM distribution and increased the total cell number. Furthermore, we show that the relative mRNA expression levels of indicators for stemness and differentiation are not significantly changed upon this bioreactor culture, whereas static culture shows variations of several indicators for stemness and differentiation. The biaxial rotating bioreactor presented here offers a homogeneous distribution of hfMSCs, enabling studies on MSCs fate in additive manufactured scaffolds without inducing undesired differentiation.

  14. On the Novel Biaxial Strain Relaxation Mechanism in Epitaxial Composition Graded La1−xSrxMnO3 Thin Film Synthesized by RF Magnetron Sputtering

    Directory of Open Access Journals (Sweden)

    Yishu Wang

    2015-11-01

    Full Text Available We report on a novel method to fabricate composition gradient, epitaxial La1−xSrxMnO3 thin films with the objective to alleviate biaxial film strain. In this work, epitaxial, composition gradient La1−xSrxMnO3, and pure LaMnO3 and La0.67Sr0.33MnO3 thin films were deposited by radio frequency (RF magnetron sputtering. The crystalline and epitaxy of all films were first studied by symmetric θ–2θ X-ray diffraction (XRD and low angle XRD experiments. Detailed microstructural characterization across the film thickness was conducted by high-resolution transmission electron microscopy and electron diffraction. Four compositional gradient domains were observed in the La1−xSrxMnO3 film ranging from LaMnO3 rich to La0.67Sr0.33MnO3 at the surface. A continuous reduction in the lattice parameter was observed accompanied by a significant reduction in the out-of-plane strain in the film. Fabrication of the composition gradient La1−xSrxMnO3 thin film was found to be a powerful method to relieve biaxial strain under critical thickness. Besides, the coexistence of domains with a composition variance is opening up various new possibilities of designing new nanoscale structures with unusual cross coupled properties.

  15. An evaluation of the processing conditions, structure, and properties (biaxial flexural strength and antibacterial efficacy) of sintered strontium-zinc-silicate glass ceramics.

    Science.gov (United States)

    Looney, Mark; Shea, Helen O'; Gunn, Lynda; Crowley, Dolores; Boyd, Daniel

    2013-05-01

    The use of artificial bone grafts has increased in order to satisfy a growing demand for bone replacement materials. Initial mechanical stability of synthetic bone grafts is very advantageous for certain clinical applications. Coupled with the advantage of mechanical strength, a material with inherent antibacterial properties would be very beneficial. A series of strontium-doped zinc silicate (Ca-Sr-Na-Zn-Si) glass ceramics have been characterized in terms of their crystalline structure, biaxial flexural strength and antibacterial efficacy based on the identification of optimum sintering conditions. All three glass ceramics, namely, BT110, BT111, and BT112 were found to be fully crystalline, with BT111 and BT112 comprising of biocompatible crystalline phases. The biaxial flexural strengths of the three glass ceramics ranged from 70 to 149 MPa and were shown to be superior to those of clinically established ceramics in dry conditions and following incubation in simulated physiological conditions. The bacteriostatic effect for each glass ceramic was also established, where BT112 showed an inhibitory effect against three of the most common bacteria found at implantation sites, namely, Enterococcus faecalis, methicillin-resistant Staphylococcus aureus (MRSA), and Pseudomonas aeruginosa. The results of the evaluation suggest that the materials studied offer advantages over current clinical materials and indicate the potential suitability of the glass ceramics as therapeutic bone grafts.

  16. Prediction of crack growth direction by Strain Energy Sih's Theory on specimens SEN under tension-compression biaxial loading employing Genetic Algorithms

    International Nuclear Information System (INIS)

    Rodriguez-MartInez R; Lugo-Gonzalez E; Urriolagoitia-Calderon G; Urriolagoitia-Sosa G; Hernandez-Gomez L H; Romero-Angeles B; Torres-San Miguel Ch

    2011-01-01

    Crack growth direction has been studied in many ways. Particularly Sih's strain energy theory predicts that a fracture under a three-dimensional state of stress spreads in direction of the minimum strain energy density. In this work a study for angle of fracture growth was made, considering a biaxial stress state at the crack tip on SEN specimens. The stress state applied on a tension-compression SEN specimen is biaxial one on crack tip, as it can observed in figure 1. A solution method proposed to obtain a mathematical model considering genetic algorithms, which have demonstrated great capacity for the solution of many engineering problems. From the model given by Sih one can deduce the density of strain energy stored for unit of volume at the crack tip as dW = [1/2E(σ 2 x + σ 2 y ) - ν/E(σ x σy)]dV (1). From equation (1) a mathematical deduction to solve in terms of θ of this case was developed employing Genetic Algorithms, where θ is a crack propagation direction in plane x-y. Steel and aluminium mechanical properties to modelled specimens were employed, because they are two of materials but used in engineering design. Obtained results show stable zones of fracture propagation but only in a range of applied loading.

  17. Multi-mode technique for the determination of the biaxial Y{sub 2}SiO{sub 5} permittivity tensor from 300 to 6 K

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, N. C., E-mail: natalia.docarmocarvalho@research.uwa.edu.au; Le Floch, J-M.; Tobar, M. E. [School of Physics, The University of Western Australia, Crawley 6009 (Australia); ARC Centre of Excellence for Engineered Quantum Systems (EQuS), 35 Stirling Hwy, Crawley 6009 (Australia); Krupka, J. [Instytut Mikroelektroniki i Optoelektroniki PW, Koszykowa 75, 00-662 Warsaw (Poland)

    2015-05-11

    The Y{sub 2}SiO{sub 5} (YSO) crystal is a dielectric material with biaxial anisotropy with known values of refractive index at optical frequencies. It is a well-known rare-earth (RE) host material for optical research and more recently has shown promising performance for quantum-engineered devices. In this paper, we report the first microwave characterization of the real permittivity tensor of a bulk YSO sample, as well as an investigation of the temperature dependence of the tensor components from 296 K down to 6 K. Estimated uncertainties were below 0.26%, limited by the precision of machining the cylindrical dielectric. Also, the electrical Q-factors of a few electromagnetic modes were recorded as a way to provide some information about the crystal losses over the temperature range. To solve the tensor components necessary for a biaxial crystal, we developed the multi-mode technique, which uses simultaneous measurement of low order whispering gallery modes. Knowledge of the permittivity tensor offers important data, essential for the design of technologies involving YSO, such as microwave coupling to electron and hyperfine transitions in RE doped samples at low temperatures.

  18. Effects of hydrostatic pressure and biaxial strains on the elastic and electronic properties of t-C8B2N2

    Science.gov (United States)

    Zhu, Haiyan; Shi, Liwei; Li, Shuaiqi; Duan, Yifeng; Zhang, Shaobo; Xia, Wangsuo

    2018-04-01

    The effects of hydrostatic pressure and biaxial strains on the elastic and electronic properties of a superhard material t-C8B2N2 have been studied using first-principles calculations. The structure is proven to be mechanically and dynamically stable under the applied external forces. All the elastic constants (except C66) and elastic modulus increase (decrease) with increasing pressure and compressive (tensile) biaxial strain ɛxx. A microscopic model is used to calculate the Vicker's hardness of every single bond as well as the crystal. The hardness of t-C8B2N2 (64.7 GPa) exceeds that of c-BN (62 GPa) and increases obviously by employing pressure and compressive ɛxx. Furthermore, the Debye temperature and anisotropy of sound velocities for t-C8B2N2 have been discussed. t-C8B2N2 undergoes an indirect to direct bandgap transition when ɛxx > 2%; however, the indirect bandgap character of the material remains under pressure.

  19. Mechanical control of the electro-optical properties of monolayer and bilayer BC3 by applying the in-plane biaxial strain

    Science.gov (United States)

    Behzad, Somayeh

    2017-11-01

    Recently, a new two-dimensional (2D) material, the 2D BC3 crystal, has been synthesized. Here, the mechanical control of the electro-optical properties of monolayer and bilayer BC3 by applying the biaxial strain is investigated. The electronic structure calculations showed that the strain-free monolayer and bilayer BC3 are indirect band-gap semiconductors with band gap of 0.62 and 0.29 eV, respectively, where the conduction band minimum (CBM) is at the M point whereas the valence band maximum (VBM) is at the Γ point. The doubly degenerated bands in the monolayer BC3 are splitted in the bilayer BC3 due to the interlayer interactions. Both monolayer and bilayer BC3 remain indirect gap semiconductor under biaxial tensile strain and their band gaps increases with strain. On the other hand, by increasing the magnitude of tensile strain, the optical spectra shift to the lower energies and the static dielectric constant increases. These findings suggest the potential of strain-engineered 2D BC3 in electronic and optoelectronic device applications.

  20. The effect of core material, veneering porcelain, and fabrication technique on the biaxial flexural strength and weibull analysis of selected dental ceramics.

    Science.gov (United States)

    Lin, Wei-Shao; Ercoli, Carlo; Feng, Changyong; Morton, Dean

    2012-07-01

    The objective of this study was to compare the effect of veneering porcelain (monolithic or bilayer specimens) and core fabrication technique (heat-pressed or CAD/CAM) on the biaxial flexural strength and Weibull modulus of leucite-reinforced and lithium-disilicate glass ceramics. In addition, the effect of veneering technique (heat-pressed or powder/liquid layering) for zirconia ceramics on the biaxial flexural strength and Weibull modulus was studied. Five ceramic core materials (IPS Empress Esthetic, IPS Empress CAD, IPS e.max Press, IPS e.max CAD, IPS e.max ZirCAD) and three corresponding veneering porcelains (IPS Empress Esthetic Veneer, IPS e.max Ceram, IPS e.max ZirPress) were selected for this study. Each core material group contained three subgroups based on the core material thickness and the presence of corresponding veneering porcelain as follows: 1.5 mm core material only (subgroup 1.5C), 0.8 mm core material only (subgroup 0.8C), and 1.5 mm core/veneer group: 0.8 mm core with 0.7 mm corresponding veneering porcelain with a powder/liquid layering technique (subgroup 0.8C-0.7VL). The ZirCAD group had one additional 1.5 mm core/veneer subgroup with 0.7 mm heat-pressed veneering porcelain (subgroup 0.8C-0.7VP). The biaxial flexural strengths were compared for each subgroup (n = 10) according to ISO standard 6872:2008 with ANOVA and Tukey's post hoc multiple comparison test (p≤ 0.05). The reliability of strength was analyzed with the Weibull distribution. For all core materials, the 1.5 mm core/veneer subgroups (0.8C-0.7VL, 0.8C-0.7VP) had significantly lower mean biaxial flexural strengths (p Empress and e.max groups, regardless of core thickness and fabrication techniques. Comparing fabrication techniques, Empress Esthetic/CAD, e.max Press/CAD had similar biaxial flexural strength (p= 0.28 for Empress pair; p= 0.87 for e.max pair); however, e.max CAD/Press groups had significantly higher flexural strength (p Empress Esthetic/CAD groups. Monolithic core

  1. Intergranular Pressure Solution in Nacl: Grain-To-Grain Contact Experiments under the Optical Microscope Dissolution sous contrainte dans NaCl : expériences de contact grain à grain sous microscope optique

    Directory of Open Access Journals (Sweden)

    Spiers C. J.

    2006-12-01

    effective diffusivity varying with contact force and on-going convergence. The results agree broadly with those of previous compaction creep experiments performed using wet halite powder. Discrepancies with other workers results for single-contact dissolution experiments can be explained in terms of differences in experimental configuration and competition between driving forces. La dissolution sous contrainte (IPS - Intergranular Pressure Solution représente un mécanisme de lithification, de compaction et de déformation à l'échelle géologique pour une large gamme de roches. Les études expérimentales d'IPS réalisées sur des agrégats de quartz n'ont pas été couronnées de succès en raison d'un taux faible d'IPS, et les expériences IPS réalisées en utilisant une halite saturée comme analogue de roche (Spiers et Schutjens, 1990 ; Hickman et Evans, 1991 ont laissé des incertitudes quant au détail des mécanismes IPS et à la structure/saturation au contact du grain dans ce matériau. La présente étude fait état de quatre expériences de dissolution de contact réalisées sous microscope optique afin d'étudier le mécanisme et la cinétique de l'IPS pour des contacts simples halite/halite et halite/verre, chargés en eau salée (température ambiante. Des forces normales de contact dans la gamme de 1,0 à 2,6 N ont été appliquées en présence d'eau salée saturée en NaCl, induisant des pressions de 0,8 à 7,4 MPa. Des pertes de masse et des convergences - fonction du temps - ont été observées pour tous les contacts. Dans tous les cas, le fait de charger le contact (ou d'augmenter la charge sur le contact a conduit à la formation immédiate d'une morphologie de contact rugueuse, composée d'un motif d'îles et de canaux, contrôlé par des caractéristiques cristallographiques, à l'échelle de quelques microns. Cette microstructure non équilibrée a évolué dans le temps vers une face de contact optiquement plate. Le processus de convergence

  2. Dimensionnement des actionneurs électriques alimentés à fréquence variable sous faible tension

    Science.gov (United States)

    Biedinger, J.-M.; Vilain, J.-P.

    1999-09-01

    In Part I we present a multidisciplinary analysis model for the prediction of functional connections between the design variables and the electromagnetical, electrical and thermal performances of a brushless permanent magnet motor. In this paper we have elaborated a design methodology for electrical motors supplied from a variable-frequency low-voltage source. The objective is to take into account the influence of the inverter's dynamics from the beginning of the design, for the same reasons as we do for electromechanical and thermal constraints. The procedure is based on a Sequential Quadratic Programming optimization method. Two techniques are used to take into account the influence of the inverter: the first one develops the performance analysis with the multidisciplinary model; the second one considers the inverter's current reference as a supplementary optimization variable for the control of the design. Optimization difficulties linked to the chopping of the converter are discuted in connection with a sensitivity analysis of the torque, with respect to the inverter's current reference; a method is proposed to enhance the performances of the algorithm. The method has been applied to the design of a permanent magnet brushless DC motor used in the propulsion system of an electrical scooter; evolution of the design with the complexity level of analysis model is evidenced. Dans une première partie nous avons développé un modèle d'analyse pluridisciplinaire qui établissait les dépendances fonctionnelles entre les variables de conception et les performances magnéto-électro-thermiques d'un moteur brushless à aimants permanents. Dans cet article nous décrivons une procédure de dimensionnement adaptée à la conception de la machine alimentée à fréquence variable sous faible tension. L'objectif est d'intégrer la dynamique du convertisseur électronique dès la phase initiale du dimensionnement, au même titre que les spécifications

  3. L'intervention sous-marine : situation actuelle et perspectives d'avenir Underwater Operations and Techniques: Current Situation and Future Outlook

    Directory of Open Access Journals (Sweden)

    Bertrand A. R. V.

    2006-11-01

    Full Text Available A l'occasion de la Conférence Internationale de Paris sur la Pénétration sous-marine(6-8 décembre 1982, cet article fait le point sur les différents moyens d'intervention sous-marine disponibles à ce jour (plongeurs, engins télécommandés, sous-marins à pression atmosphérique et sur un certain nombre de problèmes technologiques communs (matériaux, télémanipulation, navigation, sources d'énergie. Ce domaine est encore en pleine évolution et fait appel aux récentes innovations technologiques. Bien que les engins télécommandés semblent avoir actuellement la faveur des industriels, les autres moyens restent d'avenir prometteur, la complémentarité devant remplacer dans le futur la concurrence La résurrection de l'Argyronète qui doit devenir en 1985 un banc d'essais des nouvelles techniques est le témoignage de l'activité de ce secteur industriel. This article is based on the International Symposium in Paris on Underwater Operations and Techniques 6-9 December 1982. It reviews the different methods now available for underwater operations (divers, remote-controlled vehicles, atmospheric-pressure submarines and various technological problems common to all of them (materials, remote manipulation, navigating, power sources. This field is evolving rapidly and makes use of the most recent technological innovations. Although remote-controlled vehicles now seem to be favored by industrialists, the other methods still have a promising future, and the complementariness of these methods can be expected to replace rivalry among them. The resurrection of the Argyronète project, which should become a test bench for new techniques in 1985, is a good illustration of the activity going on in this industrial sector.

  4. The natural seismic hazard and induced seismicity of the european HDR (hot dry rock) geothermal energy project at Soultz-sous-Forets (Bas-Rhin, France); Alea sismique naturel et sismicite induite du projet geothermique europeen RCS (roche chaude seche) de Soultz-sous-Forets (Bas-Rhin, France)

    Energy Technology Data Exchange (ETDEWEB)

    Helm, J A

    1996-06-07

    Development of the Soultz-sous-Forets HDR (Hot Dry Rock) geothermal energy project will involve important fluid injections which will induce micro-seismic events. This thesis discusses the natural seismicity of the region and induced seismicity associated with fluid injections. A catalogue of all historical and instrument seismicity of the Soultz-sous-Forets (SSF) region has been compiled. This seismicity does not correspond to movements along the major tectonic features of the region. The area around SSF has been identified as being one where high heat flow corresponds to low seismicity. The largest well documented seismic event in the region which took place in 1952 had an epicentral intensity of VI. All important data pertaining to the series of seismic events which took place in the region from August to October 1952 have been collected and are presented. This work details the installation and operation of a permanent 3 station network of accelerometers and seismometers around the HDR site. Also the installation and operation of a mobile network of vertical seismometers during fluid injections. 167 micro-seismic events were recorded on the surface network, with magnitudes from -0.5 to 1.9. The preferential alignment of the micro-seismic cloud is N160 deg. Individual focal mechanisms of the larger seismic events correspond to an extensional tectonic regime. Stress inversion of P wave polarities indicates that the maximum stress is vertical and the intermediate and minimum stress axes horizontal. The largest of the horizontal stresses is orientated N124 deg and the smallest N34 deg. Induced seismic movement is taking place on pre-existing fractures controlled by the in situ stress seismic movement is taking place on pre-existing tectonic fractures controlled by the in situ stress field, and the largest of the induced events had a magnitude 1.9. This level of seismicity does not pose any environmental hazard to the region around Soultz-sous-Forets. (author) 151

  5. Lutte contre le Bremia de la laitue en pépinière et sous abri froid : compte-rendu d'essai 2005

    OpenAIRE

    Lambion, Jérôme

    2006-01-01

    Le mildiou de la laitue (Bremia lactucae) est la maladie la plus redoutée sur cette espèce, notamment en culture biologique d’hiver sous abris. En Provence, les dégâts sont très importants, parfois dès la pépinière, et entraînent de fortes pertes financières. Cette situation est due à deux facteurs principaux : d’une part au contournement récurrent des résistances génétiques par de nouvelles souches de Bremia (25 races déterminées à ce jour), et d’autre part à la faiblesse des méthodes de lut...

  6. Stress corrosion cracking of Inconel in high temperature water; Corrosion fissurante sous contrainte de l'Inconel dans l'eau a haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Coriou,; Grall,; Gall, Le; Vettier, [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    Some Inconel samples were subjected to hot water corrosion testing (350 deg. C), under stress slightly above the elastic limit. It has been observed that different types of alloys - with or without titanium - could suffer serious intergranular damage, including a complete rupture, within a three months period. In one case, we observed an unusual intergranular phenomenon which appeared quite different from common intergranular corrosion. (author) [French] Des essais de corrosion d'Inconel sont realises dans l'eau a 350 deg. C, et sous contrainte legerement superieure a la limite elastique. On constate que differentes varietes d'alliage avec ou sans titane donnent lieu a des accidents intergranulaires graves allant jusqu'a rupture complete en 3 mois. Dans un cas, on observe un phenomene intergranulaire particulier tres different de la corrosion intergranulaire classique. (auteur)

  7. Le pardon ou l’oubli ? La réhabilitation judiciaire en France sous la IIIe République : le cas d’Angers

    OpenAIRE

    Coltel, Antony

    2011-01-01

    La réhabilitation judiciaire constitue une forme essentielle du « pardon officiel » que la société française, sous la IIIe République, pouvait accorder aux anciens condamnés. La réhabilitation judiciaire s’applique à des condamnés ayant subi leur peine en bonne et due forme et non à des innocents injustement punis ayant obtenu la révision de leur procès. Il s’agit donc d’une mesure de pardon spécifique inaugurée par les codes napoléoniens, rétablissant le condamné dans ses droits et effaçant ...

  8. Processus d'innovation et recomposition des territoires agricoles : le cas du semis sous couvert végétal au nord du Cameroun

    OpenAIRE

    Dugué, Patrick; Olina Bassala, Jean-Paul

    2015-01-01

    Au nord du Cameroun, l'adoption des systèmes de culture sous couvert végétal (SCV) butte sur le partage des résidus de culture fourragers en saison sèche entre le bétail et la couverture du sol. Elle nécessite donc d'accroître l'offre fourragère et de prendre en compte les différents types d'élevage (villageois, semi-sédentaire, transhumant, etc.). Dans les conditions actuelles de pratique des SCV par les producteurs (faible couverture du sol, peu d'années successives en SCV) les effets atten...

  9. Identité hors territoire. Les élites espagnoles exilées en France sous la dictature de Primo de Rivera (1923-1930

    Directory of Open Access Journals (Sweden)

    Elvire Diaz

    2006-09-01

    Full Text Available Le territoire étant un point d’ancrage de l’identité individuelle et nationale, nous verrons dans ce travail si hors territoire, il peut y avoir préservation de l’identité, individuelle, collective, nationale, débouchant sur une dé-territorialisation, au sens défini par Gilles Deleuze. Notre objet d’étude portera sur le cas d’une micro-société hors territoire, les élites intellectuelles espagnoles exilées en France sous la dictature du Général Miguel Primo de Rivera (1923-1930.Le général Mig...

  10. Écrire dans la variante de l’autre : le cas de Sous les vents de Neptune de Fred Vargas

    Directory of Open Access Journals (Sweden)

    Nadine Vincent

    2014-04-01

    Full Text Available Pour tout auteur, choisir d’écrire dans une langue ou dans la variante d’une langue qui n’est pas la sienne représente un défi de taille. Nous nous intéresserons au roman Sous les vents de Neptune, de l’écrivaine française Fred Vargas, qui a situé une partie de son intrigue au Québec, sans maîtriser la notion de variation linguistique. En analysant les réactions des lecteurs européens et québécois, de même que les caractéristiques de la langue québécoise de Vargas, nous aborderons la question de l’impérialisme linguistique et de son anachronisme au xxie siècle.

  11. "Velvet":Sous-titrage de l'épisode 1 de la série de R. Campos et G.R. Neira

    OpenAIRE

    De Corte, Inès

    2017-01-01

    Sous-titrage du premier épisode de la série "Velvet" réalisée par R. Campos et G.R. Neira et produite par Bambú Producciones. Contextualisation de la série dans l'histoire et dans les jeux d'influences de l'industrie de la mode afin d'évaluer l'adaptation de la série et sa crédibilité historique. Commentaires de traduction expliquant le processus de traduction, la réflexion et la méthodologie employées. Master [120] en traduction, Université catholique de Louvain, 2017

  12. Gazettes sous influence : le Courrier du Bas-Rhin, la Gazette des Deux-Ponts et les sujets touchant la Russie vers 1770

    Directory of Open Access Journals (Sweden)

    Georges Dulac

    2016-11-01

    Full Text Available Vers 1770, la campagne anti-russe du gouvernement français tend à dégrader l’image de la Russie, ce qui lèse gravement ses intérêts, notamment quand elle doit emprunter pour financer la guerre avec la Turquie. Aussi le prince Dmitri Alexeevitch Golitsyn, ministre plénipotentiaire à La Haye, se montre-t-il alors très actif sur ce terrain. Sa correspondance avec Pétersbourg témoigne de ses efforts, aux effets inégaux, pour influer sur les informations diffusées par quelques journaux : principalement le Courrier du Bas-Rhin, publié par Jean Manzon à Trèves, sous contrôle prussien, et dans une moindre mesure les deux Gazettes des Deux-Ponts, l’une politique, l’autre littéraire. Le journaliste de Trèves, qui trouve son intérêt à prendre le parti de la Russie, met en œuvre en sa faveur un discours journalistique abondant et parfois très élaboré. Cependant, la ligne du journal subit des fluctuations sensibles, selon l’évolution de la situation et à la suite de diverses interventions, dont celles du roi de Prusse et d’autre part de Stanislas-Auguste, qui pensionne un temps le journaliste. La Gazette des deux Ponts pratique l’information orientée avec plus de finesse, et, comme la gazette littéraire, accorde une large place à la matière russe : mais sur le plan politique, son traitement reste le plus souvent sous influence française et répond rarement aux vœux de D. A. Golitsyn.

  13. Epitaxial YBa2Cu3O7 on biaxially textured (001) Ni: An approach to high critical current density superconducting tapes

    International Nuclear Information System (INIS)

    Norton, D.P.; Goyal, A.; Budai, J.D.

    1997-01-01

    In-plane aligned, c-axis oriented YBa 2 Cu 3 O 7 (YBCO) films with superconducting critical current densities, J c , as high as 700,000 amperes per square centimeter at 77 kelvin have been grown on thermo-mechanically, rolled-textured (001) Ni tapes using pulsed-laser deposition. Epitaxial growth of oxide buffer layers directly on biaxially textured Ni, formed by recrystallization of cold-rolled pure Ni, enables the growth of 1.5 micrometer-thick YBCO films with superconducting properties that are comparable to those observed for epitaxial films on single crystal oxide substrates. This result represents a viable approach for producing long-length superconducting tapes for high current, high field applications at 77 kelvin

  14. Analytical modeling of the effect of crack depth, specimen size, and biaxial stress on the fracture toughness of reactor vessel steels

    International Nuclear Information System (INIS)

    Chao, Yuh-Jin

    1995-01-01

    Fracture, toughness values for A533-B reactor pressure vessel (RPV) steel obtained from test programs at Oak Ridge National Laboratory (ORNL) and University of Kansas (KU) are interpreted using the J-A 2 analytical model. The analytical model is based on the critical stress concept and takes into consideration the constraint effect using the second parameter A 2 in addition to the generally accepted first parameter J which represents the loading level. It is demonstrated that with the constraint level included in the model effects of crack depth (shallow vs deep), specimen size (small vs. large), and loading type (uniaxial vs biaxial) on the fracture toughness from the test programs can be interpreted and predicted

  15. Investigation of in-plane biaxial low cycle fatigued austenitic stainless steel AISI 321. II. Neutron diffraction stress analysis at the IBR-2 pulsed nuclear reactor

    International Nuclear Information System (INIS)

    Taran, Yu.V.; Balagurov, A.M.; Sheverev, S.G.; ); Schreiber, J.; Bomas, H.; Korsunsky, A.M.

    2007-01-01

    The in-plane biaxial low cycle fatigued sample of the cruciform geometry from austenitic stainless steel AISI 321 was investigated on the time-of-flight neutron Fourier stress-diffractometer. The lattice parameters in the austenite matrix and the martensite inclusions created during the fatigue cycling as well as the martensite volume fraction were measured along two mutually perpendicular planar axes of the sample of the cruciform geometry by using the strain neutron scanner. The phase total residual strain components were calculated using the stress equilibrium relations. The separation of the residual stresses into macro- and microstresses was performed using the mixture rule. The measurements of the applied load-phase elastic strain responses were carried out on a uniaxial load machine. The strong difference between the phase elastic moduli was found out

  16. Prediction under Uncertainty on a Mature Field Prévision de production sous incertitude pour un champ mature

    Directory of Open Access Journals (Sweden)

    Feraille M.

    2012-04-01

    uses Gaussian process modeling and an adaptive design strategy. In the final step of the workflow, parametric response surfaces are used to approximate the reservoir production forecasts and obtain their probabilistic distribution by propagating the remaining posterior uncertainty of input parameters. Dans le cadre de l’ingénierie de réservoir, des simulateurs permettent de comprendre et prédire le déplacement des fluides dans le réservoir et ainsi d’optimiser son exploitation. Ces simulateurs prennent en entrée un grand nombre de paramètres qui peuvent être entachés d’incertitudes. Afin d’assurer une production future correcte, la comparaison des différents scénarios d’exploitation possibles doit tenir compte de ces incertitudes. Les prévisions de production ne doivent pas être évaluées en ne considérant qu’un seul cas « moyen » pour chaque scénario mais en intégrant l’incertitude sur les paramètres d’entrée. Dans le cadre de champ mature où un historique de production est disponible, le formalisme Bayésien est bien adapté pour répondre au problème des prédictions sous incertitudes. En effet, il permet de définir les incertitudes, dites a posteriori, sur les entrées du modèle de réservoir en prenant en compte à la fois les données statiques et dynamiques. Ces incertitudes a posteriori peuvent ensuite être propagées afin de calculer des prévisions de production probabilistes pour chaque scénario, tout en respectant la connaissance statique et dynamique du réservoir. Mais l’obtention des incertitudes a posteriori ainsi que la propagation de celles-ci sur les prévisions de production nécessitent un nombre souvent prohibitif de simulations du modèle réservoir. Dans cet article, nous proposons une application de plusieurs techniques statistiques avancées afin de prendre en compte les incertitudes dans les prévisions de production pour un champ mature et ce en utilisant un nombre raisonnable de simulations. Le

  17. Effects of core-to-dentin thickness ratio on the biaxial flexural strength, reliability, and fracture mode of bilayered materials of zirconia core (Y-TZP) and veneer indirect composite resins.

    Science.gov (United States)

    Su, Naichuan; Liao, Yunmao; Zhang, Hai; Yue, Li; Lu, Xiaowen; Shen, Jiefei; Wang, Hang

    2017-01-01

    Indirect composite resins (ICR) are promising alternatives as veneering materials for zirconia frameworks. The effects of core-to-dentin thickness ratio (C/Dtr) on the mechanical property of bilayered veneer ICR/yttria-tetragonal zirconia polycrystalline (Y-TZP) core disks have not been previously studied. The purpose of this in vitro study was to assess the effects of C/Dtr on the biaxial flexural strength, reliability, and fracture mode of bilayered veneer ICR/ Y-TZP core disks. A total of 180 bilayered 0.6-mm-thick composite resin disks in core material and C/Dtr of 2:1, 1:1, and 1:2 were tested with either core material placed up or placed down for piston-on-3-ball biaxial flexural strength. The mean biaxial flexural strength, Weibull modulus, and fracture mode were measured to evaluate the variation trend of the biaxial flexural strength, reliability, and fracture mode of the bilayered disks with various C/Dtr. One-way analysis of variance (ANOVA) and chi-square tests were used to evaluate the variation tendency of fracture mode with the C/Dtr or material placed down during testing (α=.05). Light microscopy was used to identify the fracture mode. The mean biaxial flexural strength and reliability improved with the increase in C/Dtr when specimens were tested with the core material either up and down, and depended on the materials that were placed down during testing. The rates of delamination, Hertzian cone cracks, subcritical radial cracks, and number of fracture fragments partially depended on the C/Dtr and the materials that were placed down during testing. The biaxial flexural strength, reliability, and fracture mode in bilayered structures of Y-TZP core and veneer ICR depend on both the C/Dtr and the material that was placed down during testing. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  18. Evolution de la perméabilité d'agrégats de sels sous contrainte liée à des circulations de fluides : dissolution, colmatage, déformation

    OpenAIRE

    Chen , Tao

    1994-01-01

    Le but de ce travail est d'étudier l'évolution de la perméabilité d'agrégats de sels sous contrainte lorsque les fluides circulant dans ces agrégats peuvent réagir avec le solide par des dissolutions et/ou des colmatages. Des essais de circulation de divers fluides à travers des échantillons de briques de sels sous contrainte ont permis de suivre l'évolution de la composition des fluides en cours d'essai. L'évolution des matériaux a été aussi caractérisée en cours d'essai (mesure de vitesse a...

  19. Effet de pratiques de fertilisation azotée sur la sensibilité d’une culture de tomate à l’oïdium et la pourriture grise en conditions de production sous serre.

    OpenAIRE

    Ozayou, Saddik

    2011-01-01

    L’azote est le principal élément nutritif utilisé pour le contrôle des maladies aériennes sous abris. Dans ce stage, nous avons étudié l’effet de trois régimes de fertilisation azotée (4 mmoles/L, 8 mmoles/L et 16 mmoles/L) sur la physiologie de la plante et la sensibilité de la tomate à l’Oidium neolycopersici et à Botrytis cinerea en conditions de production sous serre. Pour ce faire, nous avons inoculé différents organes aériens des plantes dans la serre ou au laboratoire de l’INRA d’Alény...

  20. A continuous acceleration tube of ions under 200 KV; Un tube d'acceleration continue d'ions sous 200 KV

    Energy Technology Data Exchange (ETDEWEB)

    Mongodin, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1954-07-01

    The realization of an Van de Graaff accelerator required, for the preliminary studies, the construction of a small proton accelerator, functioning at 200 kV in order to resolve some parasitic effects inherent to the accelerators tubes. The aim of this report is to describe the different organs of the accelerator tube, to explain the operating system and to encode their characteristics. The report first presents the ion source and the beam buncher permitting to inject in the accelerator tube particles of about 9 kV and very batched in a thin beam of circular section. Then the study explain the tube characteristics considered like optic system. A method to obtain precise calculation of particle trajectories is exposed. Aberrations of the system were discussed and balance of the currents on all electrodes inside the tube for different regimes of working were provided. The influence of the residual pressure in the tube were explained. The report finally ends on a part of the fundamental problem of the straining occurring inside the tubes accelerators under high tension. (M.B.) [French] La realisation d n accelerateur du type Van de Graaff a necessite, entre autres etudes preliminaires, la construction d'un petit accelerateur de protons, fonctionnant sous 200 kV afin d'eclaircir certains effets parasites propres aux tubes accelerateurs. L'objet de ce rapport est de decrire les differents organes du tube accelerateur, d'en expliquer le fonctionnement et de chiffrer leurs caracteristiques. Le memoire presente d'abord la source d'ions et le canon permettant d'injecter dans le tube accelerateur des particules de 9 kV environ et bien groupees dans un faisceau fin de section circulaire. Puis il passe a l'etude du tube considere comme systeme optique. Une methode utilisee pour le calcul precis des trajectoires des particules y est exposee. Il aborde le probleme des aberrations de ce systeme et fournit par la suite le bilan des courants sur toutes les electrodes a l

  1. High vacuum high temperature x-ray camera (1961); Chambre de diffraction de rayons x a haute temperature sous vide pousse (1961)

    Energy Technology Data Exchange (ETDEWEB)

    Baron, J L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1961-07-01

    - This camera makes it possible to carry out X-ray studies on highly oxidisable materials, up to about 900 deg. C. Most of the existing models do not provide sufficient protection against the formation of surface oxide or carbide films on the sample. The present arrangement makes it possible to operate at very low pressures: 5 x 10{sup -8} to 10{sup -7} torr, thanks to an entirely metallic apparatus. The radiation heating system consists of an incandescent lamp, outside the evacuated portion, and a reflector which concentrates the energetic flux into the sample through a silica window. The heated parts have thus only a small thermal inertia. With the apparatus it has been possible to determine the phase parameters of uranium-{alpha} up to 650 deg. C with a precision of {+-} 0.0015 A. A similar study has been carried out on a uranium-chromium alloy in the {beta}-phase up to 740 deg. C. (author) [French] Cette chambre permet l'etude, par diffraction de rayons X, de materiaux tres oxydables, ceci jusqu'a 900 deg. C environ. La plupart des modeles existant a l'heure actuelle n'assurent pas une protection suffisante de l'echantillon contre la formation de films superficiels d'oxydes ou de carbures. La disposition d'ensemble permet d'operer sous des pressions tres basses: 5.10{sup -8} a 10{sup -7} torr, grace a une construction entierement metallique. Le systeme de chauffage par rayonnement associe une lampe a incandescence, exterieure a l'enceinte sous vide, et un reflecteur, qui concentre le flux energetique sur l'echantillon, a travers un hublot de silice. Les pieces echauffees ne presentent ainsi qu'une faible inertie thermique. L'appareil a permis la determination des parametres de l'uranjum en phase a, jusqu'a 650 deg. C, avec une precision de {+-} 0,0015 A. Une etude similaire a ete effectuee sur un alliage uranium-chrome, en phase {beta}, jusqu'a 740 deg. C. (auteur)

  2. Effect of Grapefruit Seed Extract on Thermal Inactivation of Listeria monocytogenes during Sous-Vide Processing of Two Marinated Mexican Meat Entrées.

    Science.gov (United States)

    Valenzuela-Melendres, Martin; Peña-Ramos, E Aida; Juneja, Vijay K; Camou, Juan Pedro; Cumplido-Barbeitia, German

    2016-07-01

    D- and z-values for Listeria monocytogenes were obtained for two Mexican meat entrées: pork meat marinated in tomatillo (green tomato) sauce (PTS) and beef marinated in a red chili sauce (BRCS), with addition of 0, 200, and 800 ppm of grapefruit seed extract (GSE). Meat samples inoculated with L. monocytogenes were packaged in sterile bags, immersed in a water bath, and held at 55, 57.5, 60, and 62.5°C for different periods of time. Depending upon the temperature, D-values at 0 ppm of GSE ranged from 26.19 to 2.03 min in BRCS and 26.41 to 0.8 min in PTS. Adding 800 ppm of GSE to BRCS thermally treated at 55 and 62.5°C significantly decreased inactivation time by 35%. A reduction in time of 25.9, 10.6, and 40.1% at 55, 57.5, and 60°C, respectively, was observed in PTS with 800 ppm of GSE. The z-values of L. monocytogenes were not significantly affected by GSE addition; average z-values were 7.25 and 5.09°C for BRCS and PTS, respectively. Estimated thermal lethality for a 7-D log reduction of L. monocytogenes under commercial-size sous-vide conditions at a reference temperature of 55°C was reached at 78 and 71 min for BRCS without and with 800 ppm of GSE, respectively. For PTS, 7-D reduction was attained at 69 and 61 min without and with addition of 800 ppm of GSE, respectively. Supplementing both Mexican meat entrées (BRCS and PTS) with 800 ppm of GSE rendered L. monocytogenes cells more sensitive to the lethal effect of heat. The results of this study will assist the retail food industry in designing acceptance limits on critical control points pertaining to cooking regimes to effectively eliminate L. monocytogenes in BRCS and PTS sous-vide processed Mexican meat entrées.

  3. Use of radioisotopes in studying the penetration of sulphur into iron during hydrogen cathode charging; Application des radioelements a l'etude de la penetration du soufre dans le fer lors du chargement en hydrogene cathodique; Ispol'zovanie radioehlementov dlya izucheniya proniknoveniya sery v zhelezo, kogda ona zaryazhaetsya katodnym vodorodom; Aplicacion de los radioelementos al estudio de la penetracion del azufre en el hierro durante la carga con hidrogeno catodico

    Energy Technology Data Exchange (ETDEWEB)

    Besnard, S; Talbot, J [Centre National de la Recherche Scientifique, Vitry (France)

    1962-01-15

    Certain elements, such as arsenic for example, are commonly used in the laboratory to facilitate the penetration of hydrogen into iron. It has been found in industry that steel corrosion caused by hydrogen was aggravated by the presence of sulphurated hydrogen. It is an interesting question whether these elements, hitherto considered to be catalysts, merely permit a higher hydrogen absorption or whether they directly affect the metal. A study of this phenomenon is undertaken in the authors' laboratory, using electrolytic pure iron. Hydrogen supersaturation is effected by cathode charging. The addition element is S{sup 35}-labelled sodium sulphide. It is shown that, in half an hour, at -15 Degree-Sign C, the sulphur penetrates into the iron to a depth of some 120 {mu}m. A preferential localization of the sulphur at the grain boundaries is also noted. This result, which could not have been obtained without the help of radioactive tracers, has important consequences, especially for the oil industry. A similar study is made using phosphorus-32. (author) [French] Certains elements, comme l'arsenic par exemple, sont couramment utilises au laboratoire pour favoriser la penetration de l'hydrogene dans le fer. Dans l'industrie, on a constate que la corrosion des aciers due a l'hydrogene etait aggravee par la presence d'hydrogene sulfure. On pouvait se demander si ces corps, consideres jusqu'ici comme des catalyseurs, permettaient uniquement une plus grande absorption de l'hydrogene ou s'ils avaient une action directe sur le metal. L'etude de ce phenomene a ete entreprise dans notre laboratoire en utilisant du fer pur electrolytique. La sursaturation en hydrogene a ete realisee par chargement cathodique. L'element d'addition etait le sulfure de sodium marque au soufre-35. Nous avons pu montrer qu'en une demi-heure a -15 Degree-Sign C le soufre penetre dans le fer jusqu'a une profondeur de 120 {mu} environ. Par ailleurs, on a pu constater une localisation preferentielle du

  4. L'interdépendance entre les sous-systèmes conjugal et parental: une analyse personne-processus-contexte

    Directory of Open Access Journals (Sweden)

    Bigras Marc

    2000-01-01

    Full Text Available Dans le présent article nous étudions les mécanismes de transmission des difficultés socioaffectives entre les systèmes conjugal et parental sous l'effet d'une part de stress contextuels comme la pauvreté des familles et, d'autre part, des caractéristiques personnelles des membres de ces familles comme le sexe et l'âge de l'enfant. Un échantillon de couples avec ou sans enfant permet dans une première étude d'estimer l'impact de la présence de l'enfant sur le couple alors que deux autres études posent la question complémentaire de l'impact du couple sur l'enfant. Les résultats de ces études contribuent à démontrer l'interdépendance entre le couple et l'enfant alors que chaque membre de la famille peut-être une source d'influence sur les autres. Nous argumentons qu'une réponse aversive à des problèmes extrafamiliaux favorise des stress intrafamiliaux mais que cela se révèle surtout selon les caractéristiques des membres de la famille.

  5. Critical and sub-critical experiments on U-BeO lattices; Experiences critiques et sous-critiques sur reseaux U-BeO

    Energy Technology Data Exchange (ETDEWEB)

    Benoist, P.; Gourdon, Ch.; Martelly, J.; Sagot, M.; Wanner, G. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Deniz, V.; Joshi, B.V.; Sahai, K. [Atomic Energy Establishment Trombay (India)

    1958-07-01

    Sub-critical experiments have allowed us to measure the material buckling of uranium natural oxide of beryllium lattices with a grid of 15 cm, and made up of uranium bars measuring 2.60 - 2.92 - 3.56 and 4.40 cm of diameter. A critical experiment has then been conducted with hollow 1.35 per cent enriched uranium bars. A study of U-BeO 18.03 cm grid lattices is at present being conducted. (author)Fren. [French] Nous avons mesure par des experiences sous-critiques le laplacien matiere de reseaux uranium naturel-oxyde de beryllium, dont la maille carree a un pas de 15 cm, realises avec des barreaux d'uranium de diametres 2,60 - 2,92 - 3,56 - 4,40 cm. Une experience critique a ete faite ensuite avec des barres creuses d'uranium enrichi a 1,35 pour cent; l'etude des reseaux U-BeO de pas 18,03 cm est actuellement en cours. (auteur)

  6. Effects of sous-vide method at different temperatures, times and vacuum degrees on the quality, structural, and microbiological properties of pork ham.

    Science.gov (United States)

    Jeong, Kiyoung; O, Hyeonbin; Shin, So Yeon; Kim, Young-Soon

    2018-04-10

    This study evaluated the influence of different factors on pork hams cooked by sous-vide method. The quality and structural and microbiological properties of the treated samples were compared with those of controls. Samples were subjected to treatment at different combinations of temperature (61 °C or 71 °C), time (45 or 90 min), and vacuum degree (98.81% or 96.58%). The control sample was air packaged and boiled for 45 min in boiling water. Temperature and vacuum degree affected quality properties, while the effect of time was limited. Samples cooked at 61 °C showed higher moisture content, redness, and pink color of the meat juice, whereas samples cooked at 71 °C showed higher cooking loss rate, lightness, and volatile basic nitrogen values. Texture analysis indicated tenderer meat for the treatment group than the control. No microbial growth was detected in any treatment groups. Meat cooked at 61 °C and 98.81% vacuum showed more spacious arrangement of meat fiber. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. Proceedings of the European Symposium on Pressure Equipment - ESOPE 2007; Actes des Journees d'Etudes Europeennes Equipements sous Pression - ESOPE 2007

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    orientations retained for pressure equipments used in the nuclear industry, the European standards and the international collaboration, the Chinese standards and finally the recent developments of the codes and standards of the ASME in the USA. ESOPE 2007 also includes a Poster Session organized in the context of the international exhibition, which allows the companies to present their industrial realizations in parallel to the Symposium. (author) [French] Tous les trois ans, et depuis maintenant trente ans, l AFIAP organise un symposium ou les experts et acteurs oeuvrant dans le domaine des equipements sous pression, qu'ils soient fixes ou transportables, peuvent se rencontrer et echanger sur tous les developpements touchant a leur activite. Ce qui etait dans un premier temps denomme 'Congres national sur la technologie des appareils a pression', puis 'Journees d'etude sur les appareils a pression', est devenu depuis 2001 les 'Journees d'etude Europeennes sur les equipements sous pression' ou encore 'European Symposium on Pressure Equipment' (ESOPE), marquant ainsi une volonte d'ouverture a l'Europe et a l'international dans un contexte marque par la mise en oeuvre des directives europeennes applicables a ces equipements. Les journees 2001 furent plus particulierement consacrees a la mise en oeuvre des directives harmonisant la construction des equipements, et les journees 2004 ont ete plus particulierement axees sur la gestion des equipements en service. Pour le symposium ESOPE 2007, le comite d organisation a souhaite reprendre ces deux themes sous les aspects de la securite et de la competitivite, ainsi que de l'innovation. La seance pleniere du dernier jour sera entierement consacree a ces themes et comportera une Table Ronde ou s'exprimeront des representants nationaux et europeens des pouvoirs publics, des representants des fabricants et utilisateurs, ainsi que des experts engages dans la

  8. Critical and sub-critical experiments on U-BeO lattices; Experiences critiques et sous-critiques sur reseaux U-BeO

    Energy Technology Data Exchange (ETDEWEB)

    Benoist, P; Gourdon, Ch; Martelly, J; Sagot, M; Wanner, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Deniz, V; Joshi, B V; Sahai, K [Atomic Energy Establishment Trombay (India)

    1958-07-01

    Sub-critical experiments have allowed us to measure the material buckling of uranium natural oxide of beryllium lattices with a grid of 15 cm, and made up of uranium bars measuring 2.60 - 2.92 - 3.56 and 4.40 cm of diameter. A critical experiment has then been conducted with hollow 1.35 per cent enriched uranium bars. A study of U-BeO 18.03 cm grid lattices is at present being conducted. (author)Fren. [French] Nous avons mesure par des experiences sous-critiques le laplacien matiere de reseaux uranium naturel-oxyde de beryllium, dont la maille carree a un pas de 15 cm, realises avec des barreaux d'uranium de diametres 2,60 - 2,92 - 3,56 - 4,40 cm. Une experience critique a ete faite ensuite avec des barres creuses d'uranium enrichi a 1,35 pour cent; l'etude des reseaux U-BeO de pas 18,03 cm est actuellement en cours. (auteur)

  9. Three-Dimensional Packing Structure and Electronic Properties of Biaxially Oriented Poly(2,5-bis(3-alkylthiophene-2-yl)thieno[3,2- b ]thiophene) Films

    KAUST Repository

    Cho, Eunkyung

    2012-04-11

    We use a systematic approach that combines experimental X-ray diffraction (XRD) and computational modeling based on molecular mechanics and two-dimensional XRD simulations to develop a detailed model of the molecular-scale packing structure of poly(2,5-bis (3-tetradecylthiophene-2-yl) thieno[3,2-b]thiophene) (PBTTT-C 14) films. Both uniaxially and biaxially aligned films are used in this comparison and lead to an improved understanding of the molecular-scale orientation and crystal structure. We then examine how individual polymer components (i.e., conjugated backbone and alkyl side chains) contribute to the complete diffraction pattern, and how modest changes to a particular component orientation (e.g., backbone or side-chain tilt) influence the diffraction pattern. The effects on the polymer crystal structure of varying the alkyl side-chain length from C 12 to C 14 and C 16 are also studied. The accurate determination of the three-dimensional polymer structure allows us to examine the PBTTT electronic band structure and intermolecular electronic couplings (transfer integrals) as a function of alkyl side-chain length. This combination of theoretical and experimental techniques proves to be an important tool to help establish the relationship between the structural and electronic properties of polymer thin films. © 2012 American Chemical Society.

  10. Development of biaxially textured buffer layers on rolled-Ni substrates for high current YBa2Cu3O7-y coated conductors

    International Nuclear Information System (INIS)

    Paranthaman, M.; Goyal, A.; Norton, D.P.

    1996-01-01

    This paper describes the development of 3 buffer layer architectures with good biaxial textures on rolled-Ni substrates using vacuum processing techniques. The techniques include pulsed laser ablation, e-beam evaporation, dc and rf magnetron sputtering. The first buffer layer architecture consists of an epitaxial laminate of Ag/Pd(Pt)/Ni. The second buffer layer consists of an epitaxial laminate of CeO 2 /Pd/Ni. The third alternative buffer layer architecture consists of an epitaxial laminate of YSZ/CeO 2 /Ni. The cube (100) texture in the Ni was produced by cold rolling followed by recrystallization. Crystallographic orientations of the Pd, Ag, CeO 2 , and YSZ films grown were all (100). We recently demonstrated a critical- current density of 0.73x10 6 A/cm 2 at 77 K and zero field on 1.4 μm thick YBa 2 Cu 3 O 7-y (YBCO) film. This film was deposited by pulsed laser ablation on a YBCO/YSZ/CeO 2 /Ni substrate

  11. MOD approach for the growth of epitaxial CeO2 buffer layers on biaxially textured Ni-W substrates for YBCO coated conductors

    International Nuclear Information System (INIS)

    Bhuiyan, M S; Paranthaman, M; Sathyamurthy, S; Aytug, T; Kang, S; Lee, D F; Goyal, A; Payzant, E A; Salama, K

    2003-01-01

    We have grown epitaxial CeO 2 buffer layers on biaxially textured Ni-W substrates for YBCO coated conductors using a newly developed metal organic decomposition (MOD) approach. Precursor solution of 0.25 M concentration was spin coated on short samples of Ni-3 at%W (Ni-W) substrates and heat-treated at 1100 C in a gas mixture of Ar-4%H 2 for 15 min. Detailed x-ray studies indicate that CeO 2 films have good out-of-plane and in-plane textures with full-width-half-maximum values of 5.8 deg. and 7.5 deg., respectively. High temperature in situ XRD studies show that the nucleation of CeO 2 films starts at 600 C and the growth completes within 5 min when heated at 1100 C. SEM and AFM investigations of CeO 2 films reveal a fairly dense microstructure without cracks and porosity. Highly textured YSZ barrier layers and CeO 2 cap layers were deposited on MOD CeO 2 -buffered Ni-W substrates using rf-magnetron sputtering. Pulsed laser deposition (PLD) was used to grow YBCO films on these substrates. A critical current, J c , of about 1.5 MA cm -2 at 77 K and self-field was obtained on YBCO (PLD)/CeO 2 (sputtered)/YSZ (sputtered)/CeO 2 (spin-coated)/Ni-W

  12. Free vibration and biaxial buckling analysis of magneto-electro-elastic microplate resting on visco-Pasternak substrate via modified strain gradient theory

    Science.gov (United States)

    Jamalpoor, A.; Ahmadi-Savadkoohi, A.; Hosseini-Hashemi, Sh

    2016-10-01

    This paper deals with the theoretical analysis of free vibration and biaxial buckling of magneto-electro-elastic (MEE) microplate resting on Kelvin-Voigt visco-Pasternak foundation and subjected to initial external electric and magnetic potentials, using modified strain gradient theory (MSGT). Kirchhoff plate model and Hamilton’s principle are employed to extract the governing equations of motion. Governing equations were analytically solved to obtain clear closed-form expression for complex natural frequencies and buckling loads using Navier’s approach. Numerical results are presented to reveal variations of natural frequency and buckling load ratio of MEE microplate against different amounts of the length scale parameter, initial external electric and magnetic potentials, aspect ratio, damping and transverse and shear stiffness parameters of the visco-Pasternak foundation, length to thickness ratio, microplate thickness and higher modes. Numerical results of this study illustrate that by increasing thickness-to-material length scale parameter ratio, both natural frequency and buckling load ratio predicted by MSGT and modified couple stress theory are reduced because the non-dimensional length scale parameter tends to decrease the stiffness of structures and make them more flexible. In addition, results show that initial external electric and initial external magnetic potentials have no considerable influence on the buckling load ratio and frequency of MEE microplate as the microplate thickness increases.

  13. Sequential Indentation Tests to Investigate the Influence of Confining Stress on Rock Breakage by Tunnel Boring Machine Cutter in a Biaxial State

    Science.gov (United States)

    Liu, Jie; Cao, Ping; Han, Dongya

    2016-04-01

    The influence of confining stress on rock breakage by a tunnel boring machine cutter was investigated by conducting sequential indentation tests in a biaxial state. Combined with morphology measurements of breaking grooves and an analysis of surface and internal crack propagation between nicks, the effects of maximum confining stress and minimum stress on indentation efficiency, crack propagation and chip formation were investigated. Indentation tests and morphology measurements show that increasing a maximum confining stress will result in increased consumed energy in indentations, enlarged groove volumes and promoted indentation efficiency when the corresponding minimum confining stress is fixed. The energy consumed in indentations will increase with increase in minimum confining stress, however, because of the decreased groove volumes as the minimum confining stress increases, the efficiency will decrease. Observations of surface crack propagation show that more intensive fractures will be induced as the maximum confining stress increases, whereas the opposite occurs for an increase of minimum confining stress. An observation of the middle section, cracks and chips shows that as the maximum confining stress increases, chips tend to form in deeper parts when the minimum confining stress is fixed, whereas they tend to formed in shallower parts as the minimum confining stress increases when the maximum confining stress is fixed.

  14. Effect of Low-Pressure Nitrogen DC Plasma Treatment on the Surface Properties of Biaxially Oriented Polypropylene, Poly (Methyl Methacrylate) and Polyvinyl Chloride Films

    International Nuclear Information System (INIS)

    Mortazavi, S. Hamideh; Ghoranneviss, Mahmood; Pilehvar, Soheil; Esmaeili, Sina; Zargham, Shamim; Hashemi, S. Ebrahim; Jodat, Hamzeh

    2013-01-01

    In this study, commercial biaxially oriented polypropylene (BOPP), polyvinyl chloride (PVC) and poly (methyl methacrylate) (PMMA) films were treated with nitrogen plasma over different exposure times in a Pyrex tube surrounded by a DC variable magnetic field. The chemical changes that appeared on the surface of the samples were investigated using Fourier transform infrared (FT-IR) spectroscopy and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy after treatment for 2 min, 4 min and 6 min in a nitrogen plasma chamber. Effects of the plasma treatment on the surface topographies and contact angles of the untreated and plasma treated films were also analyzed by atomic force microscopy (AFM) and a contact angle measuring system. The results show that the plasma treated films become more hydrophilic with an enhanced wettability due to the formation of some new polar groups on the surface of the treated films. Moreover, at higher exposure times, the total surface energy in all treated films increased while a reduction in contact angle occurred. The behavior of surface roughness in each sample was completely different at higher exposure times. (plasma technology)

  15. Are bi-axial proximal sesamoid bone fractures in the British Thoroughbred racehorse a bone fatigue related fracture? A histological study.

    Science.gov (United States)

    Kristoffersen, M; Hetzel, U; Parkin, T D H; Singer, E R

    2010-01-01

    To investigate whether microfractures and alterations in the trabecular bone area are associated with catastrophic bi-axial proximal sesamoid bone fractures (PSBF). Proximal sesamoid bones (PSB) from 10 racehorses with PSBF and from 10 control racehorses without musculoskeletal injury were examined using the bulk basic fuchsin method. Bone histomorphometric and microfracture analysis was performed, and cases and controls compared using two-sample t-test, paired t-test, and Mann-Whitney U test. There was no significant difference in the microfracture density and the trabecular bone area between bones from case and control horses, and between fractured and non-fractured bones in case horses. Microfracture density was low in the areas of the PSB examined. Microfracture density was not significantly different between groups, indicating that propagation of micro-cracks is an unlikely predisposing pathologic alteration in PSBF in British racehorses. There was no significant difference in the bone surface area between groups, which one would expect if modelling, adaptation and an increase in bone density were associated with PSBF fracture in the case horses. Therefore, PSBF in the British racehorse does not appear to be associated with microfractures of the trabecular bone of the PSB. The PSB fractures might represent an acute monotonic fracture; however, the aetiology of the fractures remains unknown with additional research required.

  16. Experimental investigation on transformation, reorientation and plasticity of Ni47Ti44Nb9 SMA under biaxial thermal–mechanical loading

    International Nuclear Information System (INIS)

    Chen, Xiang; Peng, Xianghe; Chen, Bin; Han, Jia; Zeng, Zhongmin; Hu, Ning

    2015-01-01

    The constitutive behavior of shape memory alloy (SMA) Ni 47 Ti 44 Nb 9 specimens subjected to different thermal–mechanical loading histories was investigated experimentally. This involved the application of strain by different proportional or non-proportional paths in the biaxial ϵ−γ plane at −60 °C (M s + 30 °C), the interaction between stress-induced martensitic transformation, reorientation and plastic deformation, temperature-induced reverse martensitic transformation and strain recovery. The results show that the equivalent stress–strain curves, as well as the pure shear and pure tensile curves, depend strongly on the thermal–mechanical loading history. For specimens deformed previously to the same equivalent strains by different paths, the equivalent recovery strains after unloading are similar, as are the spans between the reverse transformation start and final temperatures. The activated martensite variants depend strongly on loading history. The recovery of the axial strain component and that of the shear strain component due to reverse transformation occur synchronously and develop along the shortest path in the ϵ−γ plane. The results may provide some new and useful information on the effects of transformation, plasticity and loading paths for further studies and applications of such materials. (paper)

  17. Hot pressing of U-UC cermets and stoichiometric uranium monocarbide; Preparation par frittage sous charge de cermets U-UC et de monocarbure stoechiometrique

    Energy Technology Data Exchange (ETDEWEB)

    Dubuisson, J; Houyvet, A; Le Boulbin, E; Lucas, R; Moranville, C [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    High density fuels, either in uranium monocarbide or in U-UC cermets have been prepared on laboratory-scale, by hot pressing of mixtures of uranium powder and graphite in suitable proportions. Uranium powder is prepared by calcium reduction of UO{sub 2} followed by an acetic leaching at low temperature. An adequate protection-treatment permits the manipulation of the powder in the open air. Uranium and Graphite powders are intimately mixed and then hot pressed in a double effect graphite die at a temperature of 900-1000 deg. C under a charge of 200 kg/cm{sup 2} during 3 hours. A special design of the die avoids the breaking of the graphite during the sintering. In this way, samples are prepared, the characteristics of which are: 1) {+-} 5 pour cent of homogeneity for a ratio height/diameter = 2. 2) almost theoretical density (98 pour cent) 3) low concentration of unreacted carbon (heat treatment of stoichiometric monocarbide can be useful for completion of reaction) 4) the micrographic examination shows: - a network of monocarbide surrounding uranium in the case of low concentration cermets (<2,5 per cent C) - two networks intimately mixed for high concentration cermets (<2,5 per cent C) - a fine grain structure for the monocarbide (10 u). 5) In every case, the X rays examinations show a fine grain structure without any orientation, and no UC{sub 2}. Some indications are given on the physical (thermal cycling, conductibility) and chemical properties (corrosion, reaction with cladding materials). (author)Fren. [French] Une methode de preparation de combustibles de haute densite, soit en monocarbure d'uranium, soit en cermets U-UC, a ete mise au point au laboratoire. Il s'agit du frittage sous charge de melanges de poudres d'uranium et de graphite en proportion convenable. La poudre d'uranium est elaboree par calciothermie de l'oxyde UO{sub 2} suivie d'un lavage acetique a basse temperature. Un traitement de protection adequat pe sa manipulation a l'air. Les poudres

  18. The Influence Of Hydrothermal Alteration And Weathering On Rock Magnetic Properties Of Granites From The Eps-1 Drilling (soultz-sous-forÊts / France)

    Science.gov (United States)

    Just, J.; Schleicher, A.; Kontny, A.; de Wall, H.

    The EPS-1 drilling in Soultz-sous-Forêts (Rhinegraben, France) recovered a core pro- file of Tertiary to Permo-Mesozoic sediments deposited on a Variscan granitic base- ment. Magnetic susceptibility (k) measurements on the core material revealed a con- tinous increase from the basement/cover boundary (kmean 0.4 x 10-3 SI) into the magnetite-bearing granite (kmean 13 x 10-3 SI) over a depth range of 1417 U 1555 m. Rock magnetic and mineralogic studies were performed for the fresh granite, the hydrothermally altered granite near a fault zone and the altered granite from the fossil land surface near the basement/cover boundary. The decrease in susceptibility can be correlated with a gradual decomposition of magnetite to hematite and an alteration of the matrix minerals feldspars, biotite and hornblende to clay minerals and carbon- ates. Along with this transition, characteristic rock magnetic signatures can be dis- criminated for different degrees of alteration. While temperature-dependent magnetic susceptibility k(T)-curves in fresh granites indicate a typical multidomain magnetite course with good reversibility, different types of irreversible courses are observed for the altered granite. However, hematite could not be identified in the k(T)-curves. Al- tered granite shows relatively weak magnetic behaviour in AF-demagnetisation exper- iments, untypical for hematite. The alteration of the fresh granite also causes a change in magnetic fabric parameter, especially of the anisotropy factor. The magnetic min- eralogy from the altered granite in respect to the changes in rock magnetic properties will be discussed.

  19. Influences de la symphonie concertante sur la musique de la Cour parisienne sous l'Empire et la Restauration (1800-1830

    Directory of Open Access Journals (Sweden)

    Dratwicki, Alexandre

    2003-12-01

    Full Text Available The origins of the very much appreciated "symphonie concertante" can be found in the importance of public concerts given in Paris at the end of the 18th century. The specific repertoire played at the French Court during the years 1800-1830 distinctly shows this vogue for the "symphonie concertante", for it reveals the still unknown importance of virtuosity. Considered as an musical entertainment for the pompous parties at the French Court or as an musical accompaniment for the masses given at the Imperial and Royal Chapel, this "decorative concertant syle" became an essential part of the Regime etiquette during the Napoleonic empire as well as the Restoration period. This music, perfectly incorporated into the official guidelines, will disappear as a consequence of the political events of 1830 and the arrival of a new aesthetic movement, the Romanticism.

    [fr] La vogue du concert public à Paris, à la fin du XVIIIe siècle, fut à l'origine de l'essor phénoménal que connut la symphonie concertante. Le répertoire de la musique de la Cour - entre 1800 et 1830 - est particulièrement représentatif de cette mode : il révèle une place encore insoupçonnée laissée à la virtuosité. Agrémentant les messes de la Chapelle ou les bals donnés lors de fastueuses soirées, ce « style concertant décoratif » devint un élément constitutif de l'apparat gouvernemental sous l'Empire et la Restauration. Une sorte d'académisme officiel que les événements politiques de 1830 et l'essor du romantisme musical feront définitivement disparaître.

  20. Experimental and numerical study of the stability of phyllosilicates in a strong thermal gradient. Test in the geothermal site of Soultz-sous-Forets

    International Nuclear Information System (INIS)

    Baldeyrou-Bailly, A.

    2003-01-01

    Thermodynamic data of hydrated phyllosilicates, in particular clay minerals are not well known. The stability fields of these minerals are not well determined; following some authors they even do not exist. We have developed an experimental approach, in which a sequence of local equilibrium states between a fluid and minerals take place in a closed gold cell along a strong thermal gradient. The experiments were conducted in the chemical systems: Mg-Al-Si-H 2 O (MASH), K-Al-Si-H 2 O (KASH), and K-Mg-Al-Si-H 2 O (KMASH). The sequences of crystallization observed along the thermal gradient are the same if one exchanges the position of the cells containing the initial reacting materials with respect to the thermal gradient end-members. The crystallization sequences correspond to local equilibrium states. Following the temperature increase (from 200 to 350 C) one observes the following sequences: di-octahedral smectite? tri-octahedral smectite; kaolinite? donbassite? tri-octahedral chlorite; smectite? illite? muscovite; or even kaolinite? illite + smectite? donbassite; commonly observed in hydrothermal systems. They allow to develop a thermodynamic model for hydrated phyllosilicates, taking into account their hydration state as a function of temperature. This model shows the stability fields of clay minerals between 200 and 350 C.The chemical and mineralogical dynamics showed in these experimental systems has been applied to predict the possible dissolutions and/or precipitations which may take place between the circulated hot fluid and the geothermal granitic reservoir in the geothermal system at Soultz-sous-Forets. These processes may affect the duration of the geothermal reservoir, as a function of evolution in the morphology of the porosity. Our experimental approach shows that feldspars and smectites are forming the major part of the total volume of silicates which may precipitate in addition to carbonates already described in previous studies. (author)

  1. Apparent Dependence of Rate- and State-Dependent Friction Parameters on Loading Velocity and Cumulative Displacement Inferred from Large-Scale Biaxial Friction Experiments

    Science.gov (United States)

    Urata, Yumi; Yamashita, Futoshi; Fukuyama, Eiichi; Noda, Hiroyuki; Mizoguchi, Kazuo

    2017-06-01

    We investigated the constitutive parameters in the rate- and state-dependent friction (RSF) law by conducting numerical simulations, using the friction data from large-scale biaxial rock friction experiments for Indian metagabbro. The sliding surface area was 1.5 m long and 0.5 m wide, slid for 400 s under a normal stress of 1.33 MPa at a loading velocity of either 0.1 or 1.0 mm/s. During the experiments, many stick-slips were observed and those features were as follows. (1) The friction drop and recurrence time of the stick-slip events increased with cumulative slip displacement in an experiment before which the gouges on the surface were removed, but they became almost constant throughout an experiment conducted after several experiments without gouge removal. (2) The friction drop was larger and the recurrence time was shorter in the experiments with faster loading velocity. We applied a one-degree-of-freedom spring-slider model with mass to estimate the RSF parameters by fitting the stick-slip intervals and slip-weakening curves measured based on spring force and acceleration of the specimens. We developed an efficient algorithm for the numerical time integration, and we conducted forward modeling for evolution parameters ( b) and the state-evolution distances (L_{{c}}), keeping the direct effect parameter ( a) constant. We then identified the confident range of b and L_{{c}} values. Comparison between the results of the experiments and our simulations suggests that both b and L_{{c}} increase as the cumulative slip displacement increases, and b increases and L_{{c}} decreases as the loading velocity increases. Conventional RSF laws could not explain the large-scale friction data, and more complex state evolution laws are needed.

  2. Caracterización del inicio y crecimiento de grietas de interfaz entre fibra y matriz bajo cargas transversales biaxiales usando el modelo de interfaz elástica lineal-frágil

    OpenAIRE

    Távara Mendoza, Luis Arístides; Mantic, Vladislav; Graciani Díaz, Enrique; Blázquez Gámez, Antonio; París Carballo, Federico

    2011-01-01

    En el presente trabajo se estudia el inicio y crecimiento de una grieta de interfaz entre fibra y matriz bajo cargas transversales biaxiales de tracción - tracción y tracción - compresión. Se considera un problema simplificado en relación a una lámina unidireccional real, con una fibra inmersa en una matriz cuyas dimensiones externas son mucho más grandes que el radio de la fibra. El objetivo es predecir por un lado las cargas de fallo (cargas criticas) que originan el despegue en ...

  3. Characterization and interpretation of a fractured rocky massif from borehole data. Boreholes of geothermal project at Soultz-sous-Forets and other examples of unidirectional sampling; Caracterisation et interpretation d`un volume rocheux fracture a partir de donnees de forages. Les forages geothermiques de Soultz-sous-Forets et autres exemples d`echantillonnages unidirectionnels

    Energy Technology Data Exchange (ETDEWEB)

    Dezayes, CH

    1995-12-18

    In this thesis, we study fractures from borehole data on two sites: in one, located at Soultz-sous-Forets (Alsace) in the Rhine graben, boreholes reach a delta Jurassic series forming a petroleum reservoir. At Soultz, fractures have been studied on cores and borehole images. Striated faults present on cores permit to determine the tectonic history of the granite, completed by field study in Vosges Massif. This history corresponds to the Rhine graben history knowing by different authors. The analysis of vertical induced fractures observed on borehole images indicates a present-day NW-SE to NNW-SSE compression. These variations of stress direction are confirmed by others in situ measurements, as hydraulic injection, micro-seismicity, etc... On cores and borehole images, numerous fractures have been observed. Most of them are linked to the E-W distension, which permits the Rhine graben opening at Oligocene. At greatest scale, in quartz minerals, the micro-fractures are constitute by fluid inclusion trails. Several sets are related to the E-W distension, but others sets are linked to compressive stages. These sets are not observed on cores. This is a under-sampling of some fractures by the boreholes, but theses fractures exit into to rock massif. On borehole images, fracture density is weakest than the cores, however the set organisation is the same. At Ravenscar, the distribution of fracture spacing along different unidirectional sampling shows a exponential negative law. However, the fracture density varies with sampling. (author) 199 refs.

  4. Contribution of the Surface and Down-Hole Seismic Networks to the Location of Earthquakes at the Soultz-sous-Forêts Geothermal Site (France)

    Science.gov (United States)

    Kinnaert, X.; Gaucher, E.; Kohl, T.; Achauer, U.

    2018-03-01

    Seismicity induced in geo-reservoirs can be a valuable observation to image fractured reservoirs, to characterize hydrological properties, or to mitigate seismic hazard. However, this requires accurate location of the seismicity, which is nowadays an important seismological task in reservoir engineering. The earthquake location (determination of the hypocentres) depends on the model used to represent the medium in which the seismic waves propagate and on the seismic monitoring network. In this work, location uncertainties and location inaccuracies are modeled to investigate the impact of several parameters on the determination of the hypocentres: the picking uncertainty, the numerical precision of picked arrival times, a velocity perturbation and the seismic network configuration. The method is applied to the geothermal site of Soultz-sous-Forêts, which is located in the Upper Rhine Graben (France) and which was subject to detailed scientific investigations. We focus on a massive water injection performed in the year 2000 to enhance the productivity of the well GPK2 in the granitic basement, at approximately 5 km depth, and which induced more than 7000 earthquakes recorded by down-hole and surface seismic networks. We compare the location errors obtained from the joint or the separate use of the down-hole and surface networks. Besides the quantification of location uncertainties caused by picking uncertainties, the impact of the numerical precision of the picked arrival times as provided in a reference catalogue is investigated. The velocity model is also modified to mimic possible effects of a massive water injection and to evaluate its impact on earthquake hypocentres. It is shown that the use of the down-hole network in addition to the surface network provides smaller location uncertainties but can also lead to larger inaccuracies. Hence, location uncertainties would not be well representative of the location errors and interpretation of the seismicity

  5. Space-time dependent impulse response of a subcritical cylindrical reactor; Reponse impulsionnelle spatio-temporelle d'un reacteur cylindrique en regime sous-critique

    Energy Technology Data Exchange (ETDEWEB)

    Cazemajou, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    In this paper, a new formulation of the spatial dependent impulse response of a subcritical reactor in a cylindrical geometry is proposed. An expression of the transfer function between a point source at the center of coordinates and the flux at a given point (r,z) is obtained by solving: by means of Laplace transform, the one group diffusion equation. In this transfer function, variables r and p (p being the Laplace variable) remain linked within a modified Bessel function. Taking the inverse Laplace transform is done by two different ways: - using the Mellin-Fourier method which separates variables r and t. This method makes it possible to establish that there is identity between the classical formulation and the new one. - using an inverse Laplace transform which keeps variables r and t linked. This method requires to approximate the inverse Laplace transform of the end factor. It is then possible to replace the radial harmonics modes series of the classical expression by a single function. This new formulation seems to be of particular interest when dealing with reactors of large size and lifetime. It is also interesting each time the harmonics play an important role. (author) [French] Dans le present rapport, on propose une nouvelle formulation de la reponse impulsionnelle spatio-temporelle d'un reacteur sous-critique, en geometrie cylindrique. Une expression de la fonction de transfert entre une source ponctuelle placee au centre des coordonnees et le flux au point courant (r,z) est obtenue en resolvant, par transformation de Laplace, l'equation de la diffusion a un seul groupe d'energie. Dans cette fonction de transfert, les variables r et p (variable de Laplace) demeurent groupees dans une fonction de Bessel modifiee. Le retour a l'original est effectue de deux manieres: - la methode de Mellin-Fourier qui separe les variables r et t, permet d'etablir l'identite entre la nouvelle formulation et la formulation classique. - un original conservant les variables

  6. Numerical modeling of the impact of temperature on the behavior of minerals in the Soultz-sous-Forêts enhanced geothermal system

    Science.gov (United States)

    Van Ngo, Viet; Lucas, Yann; Clément, Alain; Fritz, Bertrand

    2015-04-01

    Operation of the enhanced geothermal system (EGS) requires to re-inject fluid, after heat exchange at the surface to the energy production, into the geothermal reservoir. This cold re-injected fluid can cause a strong disequilibrium with the fluid and granitic rock within the geothermal reservoir and then implies the possible dissolution/precipitation of minerals. The hydrothermal alterations include the transformation of plagioclase, biotite and K-feldspar and the precipitation of various secondary minerals. The major sealing phases observed in the main fracture zones are quartz, calcite, and clay minerals. These mineralogical transformations may modify the porosity, permeability and fluid pathways of the geothermal reservoir. In the Soultz-sous-Forêts EGS (Alsace, France), the hydraulic connection between the injection well and the production well is quite poor. Therefore, understanding the impact of changes in temperature, which are caused by the re-injected fluid, on the behavior of minerals (especially for the main newly-formed minerals such as quartz, calcite and clay minerals) is a critical preliminary step for the long-term prediction of their evolution. The approach used in the present work is typically based on a geochemical code, called THERMA, which enables to calculate the changes in equilibrium constants of all primary and secondary minerals and aqueous species as a function of temperature. Our model accounted for a wide range of different mineral groups in order to make sure a large freedom for the numerical calculations. The modeling results showed that when the temperature of geothermal reservoir is cooled down, quartz, calcite, illites, galena and pyrite have tendency towards equilibrium state, which indicates that they are precipitated under the geothermal conditions. In contrast, other minerals including plagioclase, K-feldspar and biotite remained unsaturated. These behaviors of minerals were further illustrated by the Khorzinsky stability

  7. Oxidation of iron and steels by carbon dioxide under pressure (1962); Oxydation du fer et des aciers par l'anhydride carbonique sous pression (1962)

    Energy Technology Data Exchange (ETDEWEB)

    Colombie, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1962-07-01

    After having developed one of the first thermo-balances to operate under pressure, we have studied the influence of the pressure on the corrosion of iron and steels by carbon dioxide. The corrosion was followed by three different methods simultaneously: by the oxidation kinetics, by micrographs, and by radiocrystallography. We have been able to show that the influence of the pressure is not negligible and we have provided much experimental evidence: oxidation kinetics, micrographic aspects, surface precipitation of carbon, metal carburization, the texture of the magnetite layer. All these phenomena are certainly modified by changes in the carbon dioxide pressure. In order to interpret most of our results we have been led to believe that the phenomenon of corrosion by CO{sub 2} depends on secondary reactions localised at the oxide-gas interface. This would constitute a major difference between the oxidation by CO{sub 2} and that by oxygen. (author) [French] Apres avoir etudie et mis au point une des premieres thermobalances fonctionnant sous pression, nous avons etudie l'influence de la pression sur la corrosion du fer et des aciers par l'anhydride carbonique. Notre etude a ete conduite simultanement sur trois plans differents: etude des cinetiques d'oxydation, etude micrographique et etude radiocristallographique. Nous avons pu montrer que l'influence de la pression n'etait pas negligeable et nous en avons fourni un faisceau de preuves experimentales important: cinetiques d'oxydation, aspect micrographique, precipitation superficielle de carbone, carburation du metal, texture de la couche de magnetite. Tous ces phenomenes sont sans aucun doute modifies par une variation de pression du gaz carbonique. Pour interpreter la plupart de nos resultats, nous avons ete conduits a penser que le phenomene de corrosion par CO{sub 2} etait tributaire de reactions secondaires localisees a l'interface oxyde-gaz. Ce serait la une des differences fondamentales entre l'oxydation par

  8. Compatibility of various magnesium alloys with pressurized carbon dioxide at high temperatures; Compatibilite de divers alliages de magnesium avec le gaz carbonique sous pression aux temperatures elevees

    Energy Technology Data Exchange (ETDEWEB)

    Dewanckel, B; David, R; Hulin, C; Leclercq, D [Commissariat a l' Energie Atomique, 38 - Grenoble (France). Centre d' Etudes Nucleaires

    1968-07-01

    This work on the compatibility of magnesium alloys with pressurized carbon dioxide has been carried out along three lines: - testing of special alloys containing additions of zirconium, manganese, cerium, zinc, beryllium and yttrium. The results are satisfactory, generally speaking, and the corrosion kinetics are often comparable to those of conventional magnesium-zirconium alloy; - influence of the quality of the carbon dioxide, in particular the presence of water vapour or of carbon monoxide in this gas. It appears that oxidation is reduced if the carbon dioxide contains traces of water vapour, but is more pronounced if carbon monoxide is also present; - study of certain phenomena related to corrosion: size changes in the samples during tests, structural modifications in the alloys (grain-size changes, formation of a cortical zone in the case of alloys containing zirconium). The influence of thermal cycling has also been studied in a few specific tests. The results obtained make it possible to compare the behaviour of various alloys under varying conditions of long-term use, and to choose, if required, the best composition for a given application. (authors) [French] Ce travail sur la compatibilite des alliages de magnesium avec le gaz carbonique sous pression a ete particulierement oriente dans trois directions: - epreuve, d'alliages speciaux comportant des additions de zirconium, manganese, cerium, zinc, beryllium et yttrium. Les resultats sont generalement satisfaisants et les cinetiques de corrosion souvent comparables a celles de l'alliage magnesium-zirconium classique; - influence de la qualite du gaz carbonique, et notamment de la presence de vapeur d'eau ou d'oxyde de carbone dans ce gaz. Il est apparu que l'oxydation est reduite si le gaz carbonique contient des traces d'eau, mais accrue si l'oxyde de carbone est egalement present; - etude de certains phenomenes lies a la corrosion: variations dimensionnelles des echantillons au cours des essais

  9. Texturation à froid sous contraintes triaxiales de phase à haute T_c de Bi(Pb)SrCaCuO préréagie

    Science.gov (United States)

    Langlois, P.; Massat, H.; Suryanarayanan, R.

    1994-11-01

    The alignment of grains in isostatically precompacted samples of prereacted Bi{1,8}Pb{0,4}Sr{2,0}Ca{2,2}Cu{3,0}O{10,3 + x} powder has been achieved by compressive plastic deformation under isostatic pressure at room temperature. Isostatic pressures were in the range 0.1 to 1 GPa and deformation rates were led up to 57 %. Prior to sintering, X-ray diffraction measurements corroborate an expected high- T_c phase purity of nearly 85 % and indicate that the as-deformed samples have been textured with the (c-axes parallel to the pressing direction whilst a.c. susceptibility measurements ascertain a high transition temperature around 107 K. Intergranular connection does not occur until sintering at 850 ^{circ}C for 80 h and measurements indicate then that the texture has been retained. Superconducting properties themselves show sensitivity to texture through anisotropy-related distinctive irreversibility lines. L'alignement de grains de poudre Bi{1,8}Pb{0,4}Sr{2,0}Ca{2,2}Cu{3,0}O{10,3 + x} préréagie a été réalisé par déformation plastique à température ambiante d'échantillons précompactés isostatiquement et comprimés sous pression isostatique, la gamme des pressions isostatiques allant de 0,1 à 1 GPa et les taux de déformation atteignant 57 %. Les mesures de diffraction de rayons X corroborent la pureté de phase à haute T_c proche de 85 % attendue et indiquent que les échantillons ainsi déformés ont été texturés avec les plans ab perpendiculaires à la direction de compression. Les mesures de susceptibilité alternative avèrent une température élevée de transition à environ 107 K mais la connexion intergranulaire n'est assurée qu'après un frittage à 850 ^{circ}C pendant 80 h dont on vérifie qu'il conserve la texture. Enfin, la sensibilité des propriétés supraconductrices à la texturation est évaluée par le biais de lignes d'irréversibilité distinctes en fonction de l'anisotropie.

  10. Applications of sub-optimality in dynamic programming to location and construction of nuclear fuel processing plant; Application de la sous-optimalite en programmation dynamique a la localisation et la cadence optimales de construction des equipements

    Energy Technology Data Exchange (ETDEWEB)

    Thiriet, L; Deledicq, A [Commissariat a l' Energie Atomique, 92 - Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires, section des etudes economiques generales

    1968-09-01

    First, the point of applying Dynamic Programming to optimization and Operational Research problems in chemical industries are recalled, as well as the conditions in which a dynamic program is illustrated by a sequential graph. A new algorithm for the determination of sub-optimal politics in a sequential graph is then developed. Finally, the applications of sub-optimality concept is shown when taking into account the indirect effects related to possible strategies, or in the case of stochastic choices and of problems of the siting of plants... application examples are given. (authors) [French] On rappelle d'abord l'interet de la Programmation Dynamique dans les problemes d'optimisation et de Recherche Operationnelle dans les industries chimiques, et les conditions de representation d'un programme dynamique par un graphe sequentiel. On expose ensuite un nouvel algorithme de determination de politiques sous-optimales dans un graphe sequentiel. On montre enfin les applications du concept de sous-optimalite a la prise en compte d'effets indirects lies aux politiques possibles, aux choix dans l'aleatoire, a des problemes de localisation optimale d'usines... et on donne des exemples d'utilisation. (auteurs)

  11. Foreshocks and Aftershocks Detected from Stick-slip Events on a 3 m Biaxial Apparatus and their Relationship to Quasistatic Nucleation and Wear Processes

    Science.gov (United States)

    Wu, S.; Mclaskey, G.

    2017-12-01

    We investigate foreshocks and aftershocks of dynamic stick-slip events generated on a newly constructed 3 m biaxial friction apparatus at Cornell University (attached figure). In a typical experiment, two rectangular granite blocks are squeezed together under 4 or 7 MPa of normal pressure ( 4 or 7 million N on a 1 m2 fault surface), and then shear stress is increased until the fault slips 10 - 400 microns in a dynamic rupture event similar to a M -2 to M -3 earthquake. Some ruptures nucleate near the north end of the fault, where the shear force is applied, other ruptures nucleate 2 m from the north end of the fault. The samples are instrumented with 16 piezoelectric sensors, 16 eddy current sensors, and 8 strain gage rosettes, evenly placed along the fault to measure vertical ground motion, local slip, and local stress, respectively. We studied sequences of tens of slip events and identified a total of 194 foreshocks and 66 aftershocks located within 6 s time windows around the stick-slip events and analyzed their timing and locations relative to the quasistatic nucleation process. We found that the locations of the foreshocks and aftershocks were distributed all along the length of the fault, with the majority located at the ends of the fault where local normal and shear stress is highest (caused by both edge effects and the finite stiffness of the steel frame surrounding the granite blocks). We also opened the laboratory fault and inspected the fault surface and found increased wear at the sample ends. To explore the foreshocks' and aftershocks' relationship to the nucleation and afterslip, we compared the occurrence of foreshocks to the local slip rate on the laboratory fault closest to each foreshock in space and time. We found that that majority of foreshocks were generated from local slip rates between 1 and 100 microns/s, though we were not able to resolve slip rate lower than about 1 micron/s. Our experiments provide insight into how foreshocks and

  12. Thermal fatigue loading for a type 304-L stainless steel used for pressure water reactor: investigations on the effect of a nearly perfect biaxial loading, and on the cumulative fatigue life

    International Nuclear Information System (INIS)

    Fissolo, A.; Gourdin, C.; Bouin, P.; Perez, G.

    2010-01-01

    Fatigue-life curves are used in order to estimate crack-initiation, and also to prevent water leakage on Pressure Water Reactor pipes. Such curves are built exclusively from push-pull tests performed under constant and uniaxial strain or stress-amplitude. However, thermal fatigue corresponds to a nearly perfect biaxial stress state and severe loading fluctuations are observed in operating conditions. In this frame, these two aspects have been successively investigated in this paper: In order to investigate on potential difference between thermal fatigue and mechanical fatigue, tests have been carried out at CEA using thermal fatigue devices. They show that for an identical level of strain-amplitude, the number of cycles required to achieve crack-initiation is significantly lower under thermal fatigue. This enhanced damage results probably from a perfect biaxial state under thermal fatigue. In this frame, application of the multiaxial Zamrik's criterion seems to be very promising. In order to investigate on cumulative damage effect in fatigue, multi-level strain controlled fatigue tests have been performed. Experimental results show that linear Miner's rule is not verified. A loading sequence effect is clearly evidenced. The double linear damage rule ('DLDR') improves significantly predictions of fatigue-life. (authors)

  13. Tractographie globale sous contraintes anatomiques

    OpenAIRE

    Teillac , Achille

    2017-01-01

    This work aims at developing a method inferring white matter fibers reconstructed using a global spin-glass approach constrained by anatomical prior knowledge. Unlike usual methods building fibers independently from one another, our markovian approach reconstructs the whole tractogram in an unique process by minimizing the global energy depending on the spin glass configuration (position, orientation, length and connection(s)) and the match with the local diffusion process in order to increas...

  14. Tutoriel Android sous Android Studio

    OpenAIRE

    Rodriguez , Dima

    2015-01-01

    Engineering school; Le système d’exploitation Android est actuellement l’OS le plus utilisé dans le monde faisant tourner des smartphones, tablettes, montres connectées, liseuses électroniques, télévisions interactives, et bien d'autres. C’est un système, open source qui utilise le noyau Linux. Il a été créée par Android, Inc. qui fut rachetée par Google en 2005. Le développement d’applications pour Android s’effectue en Java en utilisant des bibliothèques spécifiques. Le but de ce tutoriel e...

  15. SOUS LE PAVÉ: LA PLAGE!

    DEFF Research Database (Denmark)

    Clemmensen, Thomas Juel

    2017-01-01

    of these take their point of departure in the author’s observations of material conditions and processes on the harbor in Aarhus, which highlight the city as a geological phenomenon. But mostly the thoughts are inspired by works and ideas of artists and architects, which more or less consciously have revolved...

  16. Crack Features and Shear-Wave Splitting Associated with Fracture Extension during Hydraulic Stimulation of the Geothermal Reservoir in Soultz-sous-Forêts

    Directory of Open Access Journals (Sweden)

    Adelinet M.

    2016-05-01

    Full Text Available The recent tomography results obtained within the scope of the Enhanced Geothermal System (EGS European Soultz project led us to revisit the meso-fracturing properties of Soultz test site. In this paper, we develop a novel approach coupling effective medium modeling and shear-wave splitting to characterize the evolution of crack properties throughout the hydraulic stimulation process. The stimulation experiment performed in 2000 consisted of 3 successive injection steps spanning over 6 days. An accurate 4-D tomographic image was first carried out based upon the travel-times measured for the induced seismicity [Calò M., Dorbath C., Cornet F.H., Cuenot N. (2011 Large-scale aseismic motion identified through 4-D P-wave tomography, Geophys. J. Int. 186, 1295-1314]. The current study shows how to take advantage of the resulting compressional wave (Calò et al., 2011 and shear-wave velocity models. These are given as input data to an anisotropic effective medium model and converted into crack properties. In short, the effective medium model aims to estimate the impact of cracks on velocities. It refers to a crack-free matrix and 2 families of penny-shaped cracks with orientations in agreement with the main observed geological features: North-South strike and dip of 65°East and 65°West [Genter A., Traineau H. (1996 Analysis of macroscopic fractures in granite in the HDR geothermal well EPS-1, Soultz-sous-Forêts, France, J. Vol. Geoth. Res. 72, 121-141], respectively. The resulting output data are the spatial distributions of crack features (lengths and apertures within the 3-D geological formation. We point out that a flow rate increase results in a crack shortening in the area imaged by both compressional and shear waves, especially in the upper part of the reservoir. Conversely, the crack length, estimated during continuous injection rate phases, is higher than during the increasing injection rate phases. A possible explanation for this is that

  17. Sous-produits de la désinfection dans l'eau potable des petits réseaux municipaux: variabilité spatio-temporelle, modélisation et stratégies de suivi

    OpenAIRE

    Guilherme, Stéphanie

    2014-01-01

    Les trihalométhanes (THM) et les acides haloacétiques (AHA) constituent les seules familles réglementées de sous-produits de la désinfection (SPD). Les SPD sont des composés issus de la réaction de la matière organique naturelle présente dans l’eau et du désinfectant lors du traitement de l’eau potable. La plupart de ces composés ne sont pas réglementés, même si plusieurs études ont montré que certains SPD peuvent présenter un risque toxicologique plus important que les THM et les AHA. De nos...

  18. Méthode multi-échelle pour la modélisation du flambage des tôles minces sous contraintes résiduelles - Application au laminage

    OpenAIRE

    Nakhoul , Rebecca; Montmitonnet , Pierre; Potier-Ferry , Michel

    2013-01-01

    National audience; Dans le laminage à froid, l'apparition d'une distribution hétérogène de contraintes résiduelles peut engendrer le flambage de la tôle laminée, entraînant un " défaut de planéité ". L'objectif est de définir un modèle macroscopique simple décrivant les modes et amplitudes de flambage d'une tôle sous l'effet des contraintes résiduelles issues du laminage. Le présent article présente une nouvelle méthode bi-échelle [1,2] comme une alternative du modèle de flambage développé da...

  19. Sub-critical installations for continuous evaporations of up to 200 litres/hour - description and experimental results; Installations sous-critiques d'evaporation continue jusqu'a 200 litres/heure - description et resultats experimentaux

    Energy Technology Data Exchange (ETDEWEB)

    Auchapt, P; Bouzou, G C; Sautray, R R; Jacquotte, M C [Commissariat a l' Energie Atomique, Marcoule (France). Centre de Production de Plutonium de Marcoule

    1965-07-01

    In this report are given a detailed technological description and the test results obtained with two continuous evaporation units, one of 16 l/hr, the other of 65 l/hr. These installations are sub-critical with multiplication factors (k{sub eff}) for total reflection of 0.73 and 0.77. A third evaporator of 200 litres, also sub-critical (k{sub eff} = 0.90), is given as the limiting possible case. A description is also given of simple devices without regulator for maintaining a constant level in an extra flat, separator thus making it possible to operate without supervision in perfect safety at any concentration factor. The liberal thermal characteristics and the simple operational principles constitute a sure guarantee for operation in {alpha} and {gamma} conditions. (authors) [French] Dans ce rapport, on trouvera la description technologique detaillee et les resultats obtenus au cours des essais, de deux installations d'evaporation en continu, l'une de 16 l/h, l'autre de 65 l/h. Ces installations sont sous-critiques avec des facteurs de multiplication (k{sub eff}) en reflexion totale de 0,73 et 0,77. Un troisieme evaporateur, de 200 l/h, egalement sous-critique (k{sub eff} = 0,90), est donne comme cas limite realisable. On trouvera aussi la description de dispositifs simples, sans regulateur, permettant de garder un niveau constant dans un separateur extra-plat, ce qui permet une marche sans surveillance, en toute securite, a tous les facteurs de concentration. Les caracteristiques thermiques non poussees et les principes de fonctionnement simples, sont une garantie certaine pour l'exploitation en milieu {alpha} et {gamma}. (auteurs)

  20. Anisotropically biaxial strain in non-polar (112-0) plane In x Ga1-x N/GaN layers investigated by X-ray reciprocal space mapping.

    Science.gov (United States)

    Zhao, Guijuan; Li, Huijie; Wang, Lianshan; Meng, Yulin; Ji, Zesheng; Li, Fangzheng; Wei, Hongyuan; Yang, Shaoyan; Wang, Zhanguo

    2017-07-03

    In this study, the indium composition x as well as the anisotropically biaxial strain in non-polar a-plane In x Ga 1-x N on GaN is studied by X-ray diffraction (XRD) analysis. In accordance with XRD reciprocal lattice space mapping, with increasing indium composition, the maximum of the In x Ga 1-x N reciprocal lattice points progressively shifts from a fully compressive strained to a fully relaxed position, then to reversed tensile strained. To fully understand the strain in the ternary alloy layers, it is helpful to grow high-quality device structures using a-plane nitrides. As the layer thickness increases, the strain of In x Ga 1-x N layer releases through surface roughening and the 3D growth-mode.

  1. Quantification de la Charge Virale et tests de résistance du VIH-1 aux ARV à partir d’échantillons DBS (Dried Blood Spots chez des patients Guinéens sous traitement antirétroviral

    Directory of Open Access Journals (Sweden)

    Nestor Bangoura

    2015-06-01

    Full Text Available Problématique: Comme dans plusieurs pays du Sud, le suivi virologique des patients sous traitement antirétroviral (TARV en Guinée est timide voire inexistant dans certaines localités. Le but de cette étude était d’évaluer la faisabilité technique et logistique de l’utilisation des DBS dans les tests de charge virale (CV et de génotypage. Méthode: De septembre à octobre 2010, les DBS ont été préparés à partir de prélèvements sanguins de patients adultes sous TARV. Le délai d’envoi des échantillons au laboratoire de référence était de 30 jours maximum après le prélèvement et se faisait à température ambiante. La CV a été quantifiée et les échantillons de patients en échec virologique (CV ≥ 3 log10 copies/mL ont été génotypés selon le protocole de l’ANRS. L’algorithme de Stanford version 6.0.8 a été utilisé pour l’analyse et l’interprétation des mutations de résistance. Résultats: Parmi les 136 patients inclus, 129 et 7 étaient respectivement sous première et deuxième ligne de traitement avec une médiane de suivi de 35 mois [IQR: 6-108]. L’échec virologique a été noté chez 33 patients. Parmi eux, 84.8% (n = 28/33 ont bénéficié d’ungénotypage. Le taux de résistance global était de 14% (n = 19/136. Le CRF02_AG était le sous type viral le plus prévalent (82%; n = 23. Conclusion: En plus de montrer la faisabilité technique et logistique des tests de CV et de génotypage à partir des DBS, ces résultats montrent l’intérêt de leurs utilisations dans le suivi virologique des patients sous TARV. Cette étude a permis également de documenter l’échec virologique, la résistance aux ARV et la diversité génétique du VIH-1 en Guinée. Mots clés: VIH-1, Résistance aux ARV, DBS (Dried Blood Spots, Guinée Conakry, Génotypage,Charge Virale.   Quantification of Viral load and resistance tests of HIV-1 to ARVs from dried blood spotssamples in Guinean patients undergoing

  2. Impregnation of Graphite with Liquid Silicon in a Vacuum; Impregnation du graphite avec du silicium llquide sous vide; Propitka grafita kremniem v vakuume; Impregnacion de grafito con silicio liquido en el vacio

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, V. E.; Zelenskij, V. F.; Kolendovskij, M. K.; Kolomiets, L. D.

    1963-11-15

    A study was made of the possibility of producing high thermal resistance graphite-silicon carbide materials by means of impregnating MG graphite with liquid silicon in a vacuum. An attempt is made to explain the mechanism and origins of the degradation of products during the impregnation process. On the basis of their researches the authors put forward a number of technical requirements, observance of which make it possible to produce graphite-silicon carbide materials by means of impregnation of graphite with liquid silicon-in a vacuum at temperatures of 1450 to 1600 deg. C. (author) [French] Les auteurs etudient la possibilite d'obtenir, en impregnant du graphite MG avec du silicium liquide sous vide, des materiaux au graphite, carbure et silicium resistants a la chaleur. Ils cherchent a expliquer le mecanisme et les causes de la destruction des produits au cours de l'impregnation. Se fondant sur les resultats de leurs recherches, ils enoncent un certain nombre de conditions technologiques a remplir pour obtenir les materiaux en question en impregnant le graphite de silicium liquide sous vide, a une temperature de l'ordre de 1450 a 1600 deg. C. (author) [Spanish] Los autores han estudiado la posibilidad de preparar materiales de grafito y carburo de silicio de elevada resistencia termica impregnando grafito marca MG con silicio liquido en el vacio. Proponen una explicacion del mecanismo y de las causas de la degradacion de los productos durante la impregnacion. Sobre la base de las investigaciones realizadas, los autores enumeran una serie de condiciones tecnologicas cuyo cumplimiento permite preparar piezas de grafito y carburo de silicio, impregnando el grafito con silicio liquido en el vacio a temperaturas comprendidas entre 1450 y 1600 deg. C. [Russian] V rabote izuchalas' vozmozhnost' sozdaniya grafit-karbidkremnievykh materialov s povyshennoj termostojkost'yu putem propitki grafita marki MG zhidkim kremniem v vakuume. Sdelana popytka ob{sup y

  3. A fly-wheel drive with controlled-torque clutch for a reactors cooling circuit pumps; Entrainement des pompes du circuit de refrigeration d'un reacteur par volant a embrayage sous couple controle

    Energy Technology Data Exchange (ETDEWEB)

    Riettini, A [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1964-10-15

    After a theoretical study on the slowing down of a centrifugal pump, the motion equations have been checked by means of experimental tests. In order to have important slowing down times (which is the case of the cooling pumps of a research reactor) it is necessary to add a fly-wheel. To prevent troubles when starting, a block pump-fly-wheel with clutch under controlled torque was developed. It is so possible to start the fly-wheel progressively without increasing too much power of the driving motor. (author) [French] Apres une etude theorique sur le mouvement de ralentissement d'une pompe centrifuge, les equations du mouvement ont ete verifiees par des essais pratiques. Pour obtenir des temps de ralentissement importants (cas des pompes de refrigeration d'un reacteur de recherche) il est necessaire d'y adjoindre un volant d'inertie. Pour eviter les inconvenients au demarrage, on a etudie un ensemble pompe-volant avec embrayage sous couple controle. Cette solution permet de lancer progressivement le volant sans augmentation appreciable de la puissance du moteur d'entrainement. (auteur)

  4. Apport de la simulation numérique à la compréhension des mécanismes d'interaction de cavités dans le cadre de la modélisation de l'endommagement ductile sous sollicitation dynamique

    Science.gov (United States)

    Roy, G.; Buy, F.; Llorca, F.

    2002-12-01

    L'étude présentée s'inscrit dans le cadre d'une démarche menant à la construction d'un modèle analytique ou semi analytique de comportement élasto-visco-plastique endommageable, applicable aux chargements rencontrés en configuration d'impact violent et générant de l'écaillage ductile. La prise en compte des effets de compressibilité et de micro inertie est essentielle pour modéliser la phase de croissance. Des simulations numériques globales de la structure et locales à l'échelle des hétérogénéités permettent d'évaluer les niveaux de sollicitations dans les zones susceptibles de s'endommager, dévaluer des critères analytiques de germination de l'endommagement et de comprendre les mécanismes d'interaction entre les défauts. Les effets micro inertiels et de compressibilité sont ainsi mis en évidence dans les phases de germination et de coalescence des micro défauts. II s'agit ici d'une illustration non exhaustive de travaux engagés au CEA Valduc sur le tantale, dans le cadre d'une thèse [10]. Un programme matériaux en partenariat CEA-CNRS sur la modélisation multi échelles du comportement de structures a également été initié dans ce contexte.

  5. Analytic study of plastic instabilities during tension or compression tests on a metallic plate bi-axially loaded in its plane: symmetric and antisymmetric modes with respect to the median plane

    International Nuclear Information System (INIS)

    Jouve, Dominique

    2012-01-01

    This report is a continuation of the thesis [23], devoted to the onset of necking plastic instabilities during tension tests on metallic plates bi-axially loaded in their plane. We are also interested here in compression tests, and in the development of antisymmetric defects with respect to the median plane of the plate. As in the thesis, we search for the dominant mode, i.e. the most unstable pair of wavelengths (λ1, λ2) in the loading plane. An approximate analytical formulation for the growth rate is proposed, especially for plane-strain tests in the absence of viscous effects, and for static tests in tension in the x1 and x2 loading directions. In that latter case, we retrieve published results [14][15]. For plane-strain tests, we show that infinitely dense networks of shear bands inclined at 45 deg. with respect to the loading direction instantaneously occur when heat softening prevails over work-hardening. (author)

  6. Electron bombardment fusion and continuous casting of uranium carbide. Fundamental study of the metallurgical and thermal processes; Fusion sous bombardement d'electrons et coulee continue de carbure d'uranium. Etude fondamentale des processus metallurgiques et thermiques

    Energy Technology Data Exchange (ETDEWEB)

    Trouve, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-02-01

    During a pilot production run, about 1.200 kg of uranium carbide cylindrical rods were prepared by electron bombardment fusion and continuous casting in an apparatus making it possible to operate in a constant vacuum automatically. In order to make the most of the fusion technique used, it was necessary to resolve a certain number of problems involved in this production. It was found that the energy yield for the electron bombardment heating using accelerating voltages of about 10 kV was 100 per cent; about 40 per cent of the electrons are re-emitted by back-scattering. These electrons leave the surface with practically zero energy. The fusion technique leads to the elimination of the majority of the metallic impurities. In order to explain the variations in the non-metallic impurity contents the different reactions occurring in the molten uranium monocarbide have been determined. A micrographic study of the rods obtained has shown various types of crystallization depending on the rate of casting and, despite the uniaxial symmetry of the cooling, no texture has been observed, whatever the rate of fusion employed. The aspects of the fracture surfaces observed on certain rods can be explained by theory in the domain where the material is elastic. Furthermore it has been shown that a decrease in the brittleness occurs as a result of the formation of fine precipitates of the Wiedmanstatten structure type. (authors) [French] Au cours d'une fabrication pilote, environ 1 200 kg de barreaux cylindriques de carbure d'uranium ont ete prepares par fusion sous bombardement d'electrons et coulee continue dans un appareillage permettant d'operer d'une maniere automatique sous vide constant. Afin de tirer le meilleur parti possible de la technique de fusion utilisee, il importait de repondre a un certain nombre de questions soulevees par cette fabrication. Le rendement energetique du chauffage par bombardement d'electrons pour des tensions acceleratrices de l'ordre de 10 kV a ete

  7. Les littératures contemporaines sous l´angle du concept de nation = As literaturas contemporâneas sob o aspecto do conceito de nação

    Directory of Open Access Journals (Sweden)

    Dominique Marie Philippe Geneviève Boxus

    2009-01-01

    Full Text Available Devant l´actuelle déstabilisation du concept de nation en contexte demondialisation, quelles sont la pertinence et l´actualité d´une étude des littératures contemporaines sous l´angle de la nation ? Faut-il constater l´obsolescence du concept de littérature nationale ? Pour sortir d´une impasse théorique, la perspective historique s´avèreindispensable et une étude des avatars de la nation, concept et réalité, met sur la voie d´une vision élargie où la nation est révélée comme représentation: fiction symbolique ou mythe.À côté d´un modèle mythique hégémonique privilégiant l´homogène, un autre modèle national est identifié, caractérisé par l´hétérogène et servant d´auxiliaire aux collectivités excentriques en quête d´une identification. Comme expression privilégiée du mythe de lanation, la littérature joue un rôle fondamental dans l´invention de représentations nationales inédites, ce qui justifie la pérennité d´une recherche (sociologique et/ou thématique centrée sur le littéraire contemporain (ou passé, pourvu qu´elle opère à partird´un point de vue actualisé envisagé sous l´angle de la nation.Diante da atual desestabilização do conceito de nação em contexto de globalização, quais são a pertinência e a atualidade de um estudo das literaturas contemporâneas sob o ângulo da nação? Haverá de se constatar a obsolescência do conceito de literatura nacional? Para sair de um impasse teórico, apresenta-se uma história do conceito de nação, desde suas origens no século XVIII até os dias de hoje. Abre-se caminho para uma visão ampliada da nação, ou seja, para uma definição que a revela como representação: ficção simbólica ou mito. Ao lado de um modelo mítico hegemônico que privilegia o homogêneo, um outro modelo nacional é identificado, caracterizado pelo heterogêneo e auxiliando coletividades ex-cêntricas no seu esforço de identificação. Sendo uma

  8. Study of the machining of uranium carbide rods obtained by continuous casting under electronic bombardment; Etude de l'usinage de barreaux de carbure d'uranium obtenus par coulee continue sous bombardement electronique

    Energy Technology Data Exchange (ETDEWEB)

    Rousset, P; Accary, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    The authors consider the various methods of machining uranium mono-carbide and compare them critically in the case of their application to uranium carbide obtained by fusion under an electronic bombardment and continuous casting. This study leads them to propose two mechanical machining methods: cylindrical rectification and center-less rectification, preceded by a preliminary roughing out of a cylinder, the latter appearing more suitable. A study of the machining yields as a function of the diameter of the rough bars and of the diameter of the finished rods has shown that an optimum value of the rough bar diameter exists for each value of the finished rod diameter. It is found that the yield increases as the diameter itself increases, this yield rising from 45 per cent to around 70 per cent as the diameter of the rough bars increases from 25-26 mm to 37-38 mm. (authors) [French] Les auteurs envisagent les differentes methodes d'usinage du monocarbure d'uranium et se livrent a une etude critique de celles-ci, dans le cas de leur application a l'usinage de barreaux de carbure d'uranium obtenus par fusion sous bombardement electronique et coulee continue. Cette etude les conduit a proposer deux methodes d'usinage mecanique: la rectification cylindrique et la rectification 'centerless', precedee d'un ebauchage par carottage, la seconde paraissant la plus appropriee. L'etude des rendements d'usinage en fonction du diametre des barreaux bruts et du diametre des barreaux finis, a mis en evidence une valeur optimale du diametre des barreaux bruts pour chaque valeur du diametre des barreaux usines. Elle a montre que le rendement croit lorsque le diametre croit lui-meme, ce rendement passant d'environ 45 pour cent a environ 70 pour cent, lorsque le diametre des barreaux bruts passe de 25-26 mm a 37-38 mm.

  9. The compatibility of chromium-aluminium steels with high pressure carbon dioxid at intermediate- temperatures; Compatibilite des aciers au chrome-aluminium avec le gaz carbonique sous pression aux temperatures moyennes

    Energy Technology Data Exchange (ETDEWEB)

    Leclercq, D; Loriers, H; David, R; Darras, E [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    With a view to their use in the exchangers of nuclear reactors of the graphite-gas or heavy water-gas types, the behaviour of chromium-aluminium steels containing up to 7 per cent chromium and 1.5 per cent aluminium has been studied in the presence of high-pressure carbon dioxide at temperatures of between 400 and 700 deg. C. The two most interesting grades of steel (2 per cent Cr - 0.35 per cent Al - 0.35 per cent Mo and 7 per cent Cr - 1.5 per cent Al - 0.6 per cent Si) are still compatible with carbon dioxide up to 550 and 600 deg. C respectively. A hot dip aluminised coating considerably increases resistance to oxidation of the first grade and should make possible its use up to temperatures of at least 600 deg. C. (authors) [French] Dans l'optique de leur emploi dans les echangeurs de reacteurs nucleaires des filieres graphite-gaz ou eau lourde-gaz, le comportement en presence de gaz carbonique sous pression d'aciers au chrome-aluminium, contenant jusqu'a 7 pour cent de chrome et 1,5 pour cent d'aluminium a ete etudie entre 400 et 700 deg. C. Les deux nuances les plus interessantes (2 pour cent Cr - 0,35 pour cent Al - 0,35 pour cent Mo et 7 pour cent Cr - 1,5 pour cent Al - 0,6 pour cent Si) restent compatibles avec le gaz carbonique jusqu'a 550 et 600 deg. C respectivement. Un revetement d'aluminium, effectue par immersion dans un bain fondu, ameliore notablement la resistance a l'oxydation de la premiere et doit permettre son empioi jusqu'a 600 deg. C au moins. (auteurs)

  10. La sous-traitance au Brésil : un phénomène à la fois ancien et nouveau Subcontracting in Brazil: a phenomenon both new and old La subcontratación en Brasil : un fenómeno antiguo y nuevo a la vez

    Directory of Open Access Journals (Sweden)

    Graça Druck

    2009-05-01

    Full Text Available L’objectif de l’article est de discuter la sous-traitance aujourd’hui au Brésil. Nous discutons dans l’article le processus de flexibilisation et de précarisation du travail au Brésil, en prenant comme objet d’étude la sous-traitance, en tant qu’une des principales politiques de gestion et d’organisation du travail dans le cadre de la restructuration productive. Nous présentons une synthèse du processus de sous-traitance observé ces dernières années dans le pays, sous ses anciennes et nouvelles modalités, et nous analysons les résultats empiriques récents sur la sous-traitance dans des entreprises industrielles à haut risque pour l’environnement et la santé des travailleurs, dans la Région Métropolitaine de Salvador/Bahia/Brésil, de même que nous indiquons les principales de formes de résistance et de contre-pouvoirs construits contre la précarisation du travail et la sous-traitance.The purpose of the article is to discuss current subcontracting in Brazil. Our study subject « subcontracting as one of the main work management and organization policies in the framework of productive restructurings » used to discuss the work flexilibization and precarization process in Brazil. We present a synthesis of the subcontracting process observed in recent years in this country, under its old and new conditions, and we analyze the recent empirical results on subcontracting in industrial enterprises at high risk to the environment and workers’ health, in the metropolitan region of Salvador/Bahia, Brazil. We also identify the main forms of resistance and the counterbalances developed against work precarization and subcontracting.El objetivo de este artículo es discutir la tercerización en el Brasil contemporáneo. Se discute el proceso de flexibilización y de precarización del trabajo en Brasil, tomando como objeto de estudio la subcontratación como una de las principales políticas de gestión y de organizaci

  11. A study of uranium-thorium mixed lattices; Etude de reseaux mixtes uranium - thorium

    Energy Technology Data Exchange (ETDEWEB)

    Bacher, P; Eckert, R; Mazancourt, R de [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1957-07-01

    Some subcritical experiments have been carried out during the charging of the pile G1 by introducing thorium bars in a regular lattice into the pile. The spreading out of these experiments over a period of three months has permitted: a) work on a pile gradually increasing in size and b) measurements on comparable charges in so far that they have either the same number of bars of thorium, or the same concentration of thorium. From the measurements at constant charge and at constant concentration, it is possible by extrapolation to determine the critical charges and concentrations. The values obtained have showed that the material Laplacian of the lattice depends linearly on the thorium concentration and must cancel out for a concentration T = 8.8 {+-} 0.3 per cent by volume. These results have been found, to a very good approximation, by a simple calculation. (author) [French] Des experiences sous-critiques ont ete effectuees au cours du chargement de la pile G1 en introduisant des barres de thorium reparties suivant un reseau regulier dans la pile. L'etalement de ces experiences sur trois mois a permis d'operer sur une pile de plus en plus grosse et de faire un grand nombre de mesures sur des chargements comparables par le fait qu'ils avaient soit le meme nombre de barres de thorium, soit la meme concentration en thorium. A partir des mesures a chargement constant et a concentration constante, il a ete possible de determiner par extrapolation les chargements et concentrations critiques. Les valeurs obtenues ont montre que le laplacien matiere moyen du reseau dependait lineairement de la concentration en thorium, et devrait s'annuler pour une concentration T = 8,8 {+-} 0,3% en volume. Ces resultats ont ete retrouves avec une tres bonne approximation par un calcul elementaire. (auteur)

  12. Experimental study of columns partially filled with concrete under compressive axial loads Etude expérimentale des colonnes partiellement remplis par le béton sous charge axiale

    Directory of Open Access Journals (Sweden)

    Achoura D.

    2012-09-01

    Full Text Available Dans cette étude, on présente les résultats expérimentaux obtenus sur des poteaux mixtes béton-acier mince réalisés par soudures. Un total de 24 profilés en acier, et en forme de I a été testé sous charge de compression uni-axiale à l’âge de 28 jours. les spécimens ont été réparties comme suit: 4 à vides, 4 partiellement remplies avec un béton ordinaire sans l’addition des connecteurs, 4 renforcés par des connecteurs de cisaillements de type cornière en U, 4 autres l’ont été avec des connecteurs de cisaillements type goujons et 8 restants ont été renforcés avec des liens transversaux d’espacement 100mm, 50mm, soudés aux bouts des ailes opposées. Les principaux paramètres étudiés sont: l’élancement du profilé, le type de connecteur de renforcement. A partir des résultats d’essais obtenus, il est confirmé que les parois minces sont plus sensibles de l’apparition au voilement et la longueur des profilés a un effet considérable sur la capacité portante et le mode de rupture. L’addition des connecteurs de renforcement a confirmé l’augmentation de la charge ultime par rapport aux profilés sans connecteurs. In the present work, results of tests conducted on thin welded steel-concrete stubs are presented. A total of 24 stubs an I steel section were tested under axial compression at 28 days after the date of casting, 4 were empty, 4 filled with normal concrete, 8 columns had shear connecters welded along the centreline of the web, and 8 columns had steel rods welded between the tips of opposing flanges on both sides of the spacing of the transverse link 100 mm and 50 mm. The main parameters studied were: the heel height, and type of connector strengthening. From the test results, it is confirmed that the thin walls are more sensitive to the appearance local buckling and the length of the profiles has a significant effect on the bearing capacity and failure mode. The bearing capacity was increased

  13. Study of the machining of uranium carbide rods obtained by continuous casting under electronic bombardment; Etude de l'usinage de barreaux de carbure d'uranium obtenus par coulee continue sous bombardement electronique

    Energy Technology Data Exchange (ETDEWEB)

    Rousset, P.; Accary, A. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    The authors consider the various methods of machining uranium mono-carbide and compare them critically in the case of their application to uranium carbide obtained by fusion under an electronic bombardment and continuous casting. This study leads them to propose two mechanical machining methods: cylindrical rectification and center-less rectification, preceded by a preliminary roughing out of a cylinder, the latter appearing more suitable. A study of the machining yields as a function of the diameter of the rough bars and of the diameter of the finished rods has shown that an optimum value of the rough bar diameter exists for each value of the finished rod diameter. It is found that the yield increases as the diameter itself increases, this yield rising from 45 per cent to around 70 per cent as the diameter of the rough bars increases from 25-26 mm to 37-38 mm. (authors) [French] Les auteurs envisagent les differentes methodes d'usinage du monocarbure d'uranium et se livrent a une etude critique de celles-ci, dans le cas de leur application a l'usinage de barreaux de carbure d'uranium obtenus par fusion sous bombardement electronique et coulee continue. Cette etude les conduit a proposer deux methodes d'usinage mecanique: la rectification cylindrique et la rectification 'centerless', precedee d'un ebauchage par carottage, la seconde paraissant la plus appropriee. L'etude des rendements d'usinage en fonction du diametre des barreaux bruts et du diametre des barreaux finis, a mis en evidence une valeur optimale du diametre des barreaux bruts pour chaque valeur du diametre des barreaux usines. Elle a montre que le rendement croit lorsque le diametre croit lui-meme, ce rendement passant d'environ 45 pour cent a environ 70 pour cent, lorsque le diametre des barreaux bruts passe de 25-26 mm a 37-38 mm.

  14. Kinetic Modeling of Vacuum Gas Oil Hydrotreatment using a Molecular Reconstruction Approach Modélisation cinétique de l’hydrotraitement de distillats sous vide utilisant une approche de reconstruction moléculaire

    Directory of Open Access Journals (Sweden)

    Charon-Revellin N.

    2010-10-01

    Full Text Available Vacuum Gas Oils (VGO are heavy petroleum cuts (boiling points ranging from 350 to 550 ˚C that can be transformed into valuable fuels (gasolines, diesels by fluid catalytic cracking or hydrocracking. Prior to these conversion processes, hydrotreating is required in order to eliminate the impurities in VGOs. The hydrotreatment process enables to meet the environmental specifications (total sulfur contents and to prevent nitrogen poisoning of conversion catalysts. In order to develop a kinetic model based on an accurate VGOs molecular description, innovative analytical tools and molecular reconstruction techniques were used in this work. A lumped model using a Langmuir-Hinshelwood representation was developed for hydrodearomatization, hydrodesulfurization and hydrodenitrogenation of the VGO. This lumped model was successfully applied to the experimental feed pretreatment data and was able to predict evolution of concentration of the aromatics, nitrogen and sulfur species. Les Distillats Sous Vide (DSV sont des coupes pétrolières lourdes (gamme de températures d'ébullition 350 à 550 °C qui peuvent être valorisées en carburants (essence, gazole par craquage catalytique ou par hydrocraquage. Un hydrotraitement est requis avant ces procédés de conversion afin d'éliminer les impuretés du DSV. De cette manière, le procédé d'hydrotraitement permet d'attendre les spécifications environnementales (teneur en soufre ainsi que de prévenir l'empoisonnement par les composés azotés des catalyseurs de conversion. De manière à pouvoir développer un modèle cinétique basé sur une description moléculaire précise des DSV, des outils analytiques innovant et des techniques de reconstruction moléculaire ont été utilisés dans ce travail. Un modèle cinétique de regroupement utilisant une représentation de type Langmuir-Hinshelwood a été développé pour l'hydrodésaromatisation, l'hydrodésulfuration et l'hydrodésazotation des DSV. Ce

  15. Comportement en vapocraquage de molécules modèles et de distillats sous vide hydrotraités. Deuxième partie : pyrolyse de molécules modèles représentatives des distillats sous vide bruts et hydrotraités Steam-Cracking Behavior of Model Molecules and Hydrotreated Vacuum Distillates Part Two: Pyrolysis of Model Molecules Representative of Unprocessed and Hydrotreated Vacuum Distillates

    Directory of Open Access Journals (Sweden)

    Freund E.

    2006-11-01

    Full Text Available La pyrolyse de molécules modèles a permis sur la base d'écarts de rendements obtenus entre le n -décane et leur mélange à 20 % avec celui-ci, l'établissement d'une échelle de potentialité de craquage présentée précédemment. L'approche des phénomènes de pyrolyse par des schémas réactionnels simplifiés est développée dans le présent article pour des molécules modèles, exemples de chaque grande famille susceptible de constituer le distillat sous vide : le perhydrophénanthrène pour les naphtènes lourds, l'octahydrophénanthrène symétrique pour les naphténoaromatiques, le naphtalène et l'alpha méthylnaphtalène pour les aromatiques méthylés ou non, le dodécylbenzène pour les aromatiques substitués par une longue chaîne aliphatique. Le cas de l'acénaphtylène a été examiné à part. On the basis of differences in yields obtained between n-decane and a 20% mixture of model molecules with n-decane, the pyrolysis of model molecules was used to determine a cracking potentiality scale that was previous described. The present article describes the approach to pyrolysis phenomena by simplified reaction mechanisms for model molecules taken from each major family liable to make up vacuum distillate, i. e. perhydrophenanthrene for heavy naphthenes, symmetrical octahydrophenanthrene for naphthenoaromatics, naphthalene and alpha-methynaphthalene for methylated or nonmethylated aromatics, dodecylbenzene for aromatics substituted for by a long aliphatic chain. The case of acenaphthylene is examined separately.

  16. Comportment of various magnesium alloys in carbon dioxide under pressure, between 400 and 600 deg; Compatibilite de divers alliages de magnesium avec le gaz carbonique sous pression entre 400 et 600 deg

    Energy Technology Data Exchange (ETDEWEB)

    Darras, R; Baque, P; Chevilliard, C [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    'magnesium oxyde fritte'. Les echantillons, preleves dans des produits files, sont convenablement polis, deux etats de surface reproductibles etant realises a titre comparatif. Les essais ont ete effectues dans le gaz carbonique purifie, aux pressions de 25 et 60 atmospheres, et a des temperatures allant de 400 a 600, au moyen d'autoclaves speciaux en acier inoxydable, chauffes exterieurement. Leur duree est en general superieure a 1000 heures. Les equations des courbes d'augmentation de poids obtenues sont du type ({delta}p){sup n} = k.t (({delta}p en mg/cm{sup 2} et t en heures), l'exposant n etant voisin de 2, du moins jusqu'a 500 deg. C. En se referant a des resultats precedemment acquis quant a certains de ces materiaux exposes dans le gaz carbonique sous pression atmospherique et sous 15 atmospheres, il apparait que: 1) Pour un materiau determine: - a une pression donnee, l'oxydation augmente avec la temperature, - a une temperature donnee, l'oxydation augmente avec la pression, - dans les memes conditions de temperature et de pression, les resultats obtenus varient peu suivant les deux etats de surface etudies; 2) les alliages Mg-Zr presentent une resistance a l'oxydation amelioree par rapport au magnesium non allie; 3) l'alliage magnox est beaucoup moins avantageux dans le gaz carbonique que dans l'air, par rapport aux autres alliages. D'une facon generale, les courbes d'oxydation tendant vers un palier apres un certain temps d'exposition, la compatibilite de tous les alliages consideres avec le gaz carbonique apparait satisfaisante jusqu'a une temperature voisine de 500 deg. C, dans les conditions operatoires presentement definies; au dessus de 500 deg. C, des differences notables apparaissent entre les divers alliages, mais des phenomenes de sublimation interferent avec ceux d'oxydation, de sorte qu'un classement des divers materiaux ne peut etre base que sur leur resultante. (auteur)

  17. Radioinitiation of Chain Branched Reactions and its Sensitization; Amorcage sous rayonnement des reactions par ramification en chaine; sensibilisation du processus; Radiatsionnoe initsiirovanie tsennykh razvetvlennykh reaktsij i ego sensibilizatsiya; Radioiniciacion de reacciones en cadena ramificadas y medios para aumentar su sensibilidad

    Energy Technology Data Exchange (ETDEWEB)

    Barelko, E V; Kartashova, L I; Komarov, P N; Proskurnin, M A [Karpov Physico-Chemical Institute, Moscow, Union of Soviet Socialist Republics (Russian Federation)

    1960-07-15

    This paper describes the results of experiments by the writers with radioinitiation of chain branched reactions of the oxidation of organic compounds. The function of radiation as an initiating agent is described with reference to the oxidation of several unsaturated hydrocarbons and butanol. The reaction is self-accelerating and proceeds spontaneously after radiation has ceased. A detailed investigation was made of a process from oxidizing benzene, which has a high radiation resistance. The writers devised a method of sensitizing the radioinitiation of the oxidation of radiation-resistant substances by chemically inert but non-radiation-resistant substances. The main quantitative features of the process for the radiooxidation of benzene are stated to be the accumulation of various reaction products, and the effect of temperature, pressure, power and radiation dosage on the process of such accumulation. Information was obtained about the mechanism of the process. The design of circulating equipment is described. (author) [French] Dans ce memoire, les auteurs presentent les resultats d'une etude consacree a l'amorcage sous rayonnement de reactions, d'oxydation des composes organiques, par ramification en chaine. Ils montrent le role des rayonnements en tant qu'agents d'amorcage de la reaction, en citant comme exemples l'oxydation de certains hydrocarbures non satures et du butanol. La reaction possede un caractere d'auto-acceleration et continue spontanement lorsque l'action des rayonnements a cesse. La reaction d'oxydation du benzene a ete etudiee en detail; elle est caracterisee par la haute stabilite de la substance vis-a-vis de l'action des rayonnements. Les auteurs formulent les principes de la sensibilisation, par l'action de substances instables vis-a-vis des rayonnements de l'amorcage sous rayonnement de la reaction d'oxydation de substances stables vis-a-vis des rayonnements et chimiquement inertes. Le memoire fournit les caracteristiques quantitatives

  18. Durabilité des structures en béton et robustesse vis-à-vis des actions accidentelles

    OpenAIRE

    TOUTLEMONDE, François; LABORATOIRE CENTRAL DES PONTS ET CHAUSSEES - LCPC

    2007-01-01

    L'expérience du fonctionnement réel des structures en béton existantes, spécialement sous conditions environnementales extrêmes, sous chargement accidentel sévère, ou au bout d'un vieillissement en service de longue durée, fait ressortir la nécessité de mieux intégrer dans la conception de la structure l'objectif de la durabilité, l'enjeu des nouveaux concepts fiabilistes pour une conception en vue de la durabilité, l'intérêt de la spécification performantielle du matériau, l'importance de la...

  19. Le CERN sous le feu des syndicats

    CERN Multimedia

    Lalive d'Epinay, Marc

    2002-01-01

    In order to find the money needed to complete the LHC, CERN has made savings by outsourcing some jobs, especially maintenance and cleaning. This decision has been strongly criticised by French and Swiss trade unions who claim that employees are suffering (0.5 page)

  20. 18 octobre 2013 - Le Préfet de l’Ain L. Touvet signe le livre d'or avec le Directeur général du CERN R. Heuer et le Chef du Département Technologie F. Bordry. Photo de groupe, de gauche à droite: T. Kupisz, Secrétaire général de la sous préfecture de Gex; L. Miralles, Chef du Département Infrastructure et services généraux; F. Eder, Délégué aux Relations avec les Etats hôtes; S. Donnot, Sous-préfet de Gex; L. Touvet, Préfet de l'Ain; E. Sches, Sous-préfète de Nantua; E.Gröniger-Voss, Conseiller juridique du CERN; R. Heuer, Directeur général; F. Bordry, Chef du Département Technologie et P. Bloch, Chef du Département Physique.

    CERN Multimedia

    Anna Pantelia

    2013-01-01

    18 octobre 2013 - Le Préfet de l’Ain L. Touvet signe le livre d'or avec le Directeur général du CERN R. Heuer et le Chef du Département Technologie F. Bordry. Photo de groupe, de gauche à droite: T. Kupisz,\tSecrétaire général de la sous préfecture de Gex; L. Miralles, Chef du Département Infrastructure et services généraux; F. Eder, Délégué aux Relations avec les Etats hôtes; S. Donnot, Sous-préfet de Gex; L. Touvet, Préfet de l'Ain; E. Sches, Sous-préfète de Nantua; E.Gröniger-Voss, Conseiller juridique du CERN; R. Heuer, Directeur général; F. Bordry, Chef du Département Technologie et P. Bloch, Chef du Département Physique.

  1. Modelization of ratcheting in biaxial experiments

    International Nuclear Information System (INIS)

    Guionnet, C.

    1989-08-01

    A new unified viscoplastic constitutive equation has been developed in order to interpret ratcheting experiments on mechanical structures of fast reactors. The model is based essentially on a generalized Armstrong Frederick equation for the kinematic variable; the coefficients of the dynamic recovery term in this equation is a function of both instantaneous and accumulated inelastic strain which is allowed to vary in an appropriate manner in order to reproduce the experimental ratcheting rate. The validity of the model is verified by comparing predictions with experimental results for austenitic stainless steel (17-12 SPH) tubular specimens subjected to cyclic torsional loading under constant tensile stress at 600 0 C [fr

  2. Bi-axial Vibration Energy Harvesting

    Science.gov (United States)

    2012-07-01

    included early dedicated portable signal averaging equipment, Nomad, CT4 and F18 fatigue test control systems and some field trials. Currently he is...and repairs to acoustically- fatigued structures. ____________________ ________________________________________________ UNCLASSIFIED...Physicists at the Tokyo Institute of Technology investigated various piezoceramic materials [20], developing lead zirconate titanate ( PZT ) in around 1952

  3. Evaluation of a Biaxial Test Fixture.

    Science.gov (United States)

    1983-01-01

    TD 1 a 1 I 1 ! II : ill « \\ \\ \\ X \\ 1 X X I rH 0 _ i0 2: \\ \\ 1 \\ \\ X c...i 00 o • 1—1 «4 TO x; 1 •H P X bO < c 0) 9 i—1 H Lft 03 1 C TD «4 I z <D 2: +J «-4 C fc <t H O oc «i- • & CMW w a...a, »<A T) «4 i-t C a. (0 3 o C O o S-i fn • CD < •P C £ flj M P • bO «4 ’n C ID O 0) 1 i—I H P 1 O 13 • 0> i-H

  4. Composite biaxially textured substrates using ultrasonic consolidation

    Science.gov (United States)

    Blue, Craig A; Goyal, Amit

    2013-04-23

    A method of forming a composite sheet includes disposing an untextured metal or alloy first sheet in contact with a second sheet in an aligned opposing position; bonding the first sheet to the second sheet by applying an oscillating ultrasonic force to at least one of the first sheet and the second sheet to form an untextured intermediate composite sheet; and annealing the untextured intermediate composite sheet at a temperature lower than a primary re-crystallization temperature of the second sheet and higher than a primary re-crystallization temperature of the first sheet to convert the untextured first sheet into a cube textured sheet, wherein the cube texture is characterized by a .phi.-scan having a FWHM of no more than 15.degree. in all directions, the second sheet remaining untextured, to form a composite sheet.

  5. Determination of bore efficiency loss employed as powder in boral fabrication, proportionately to the dimension of grain; Determination de la reduction d'efficacite du bore ou d'un autre absorbeur employe sous forme de poudre dissemine dans un produit non absorbant, en fonction de la grosseur des grains

    Energy Technology Data Exchange (ETDEWEB)

    Laforge, P; Millot, J P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1957-07-01

    Authors' mind was attracted by the importance of bore granulometry when employed as powder in boral fabrication. The calculation, object of this report, permits to give values for bore efficiency loss, proportionately to the dimension of spherical or ellipsoidal supposed grains. Grains to be employed should exceptionally only exceed 20 {mu} for a correspondent efficiency loss of 8 per cent about. (author) [French] L'attention des auteurs a ete attiree sur l'importance de la granulometrie du bore employe sous forme de poudre dans la fabrication du boral. Le calcul qui fait l'objet de ce rapport permet de chiffrer la perte d'efficacite du bore en fonction de la dimension des grains supposes spheriques ou ellipsoidaux. Les grains a employer ne devraient qu'exceptionnellement etre superieurs a 20 microns, ce qui correspond a une perte d'efficacite d'environ 8 pour cent. (auteur)

  6. Mike Davis, Génocides tropicaux. Catastrophes naturelles et famines coloniales (1870-1900. Aux origines du sous-développement, Paris, La Découverte, 2003, 479 p., trad. Late Victorian Holocausts, El Niño Famines and the Making of the Third World, 2001.

    Directory of Open Access Journals (Sweden)

    Cyrille Ferraton

    2005-04-01

    Full Text Available C’est à une histoire en grande partie négligée et méconnue qu’est consacré l’ouvrage de Mike Davis Génocides tropicaux publié en 2001 sous le titre Late Victorian Holocausts, El Niño Famines and the Making of the Third World. L’Inde, la Chine, le Brésil, l’Afrique du Nord, l’Afrique australe, les Philippines, en fait, un grand nombre de pays qu’Alfred Sauvy désignera en 1952 par pays du « tiers-monde », connurent à la fin du XIXe siècle et au tout début du XXe siècle trois périodes climatique...

  7. Effect of high energy electrons on the skin and on the underlying tissues of the rabbit. A clinical and histological study; Effets des electrons de haute energie sur la peau et les tissus sous-jacents du lapin. Etude clinique et histologique

    Energy Technology Data Exchange (ETDEWEB)

    Legeay, G; Vialettes, H; Adnet, J J; Court, L; Masse, R [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1967-07-01

    The authors consider in this report the effects of high-energy electrons on rabbit teguments and on the underlying tissues after a single high dose irradiation. After briefly considering the mechanism of interaction between the electrons and matter as a function of their energy, the authors describe the dosimetry carried out, as a function of the irradiation device. The animal received surface doses of 5700 to 22100 rads in the thigh; the electron energy varied from 21 to 30 MeV. A clinical study was carried out over a period of nine months with a view to following the evolution of the damage and the functional degradation of the underlying tissues. A histological study of the induced damage was made after a second irradiation using 30 MeV electrons to produce doses of 16400 rads. Interesting observations were made concerning the damage caused to muscular and nerve tissues. (authors) [French] Les auteurs etudient, dans ce rapport, les effets des electrons de haute energie sur les teguments du lapin et les tissus sous-jacents apres une irradiation unique a dose elevee. Apres un rappel du mecanisme de l'interaction des electrons avec la matiere en fonction de leur energie, la dosimetrie realisee est exposee en fonction du dispositif d'irradiation. Les animaux ont recu, au niveau de la cuisse, des doses en surface de 5700 a 22100 rads; les energies des electrons vont de 21 a 30 MeV. Une etude clinique des lesions, observees pendant 9 mois, decrit leur evolution ainsi que les alterations fonctionnelles des tissus sous-jacents. Une etude histologique des lesions induites a ete realisee au cours d'une seconde experience pour des doses de 16400 rads avec des electrons de 30 MeV. D'interessantes observations ont ete faites concernant les lesions des tissus musculaires et nerveux. (auteurs)

  8. The Subcritical Assembly for High-Temperature Use; Assemblage Sous-Critique Pour Emploi a Haute Temperature; K voprosu o podkriticheskoj sborke dlya ispol'zovaniya pri vysokikh temperaturakh; Conjunto Subcritico para Temperatura Elevada

    Energy Technology Data Exchange (ETDEWEB)

    Sakurai, Y.; Sekiya, T.; Suita, T. [Osaka University (Japan); Hishida, H.; Hamada, H.; Nagashima, K. [Sumitomo Atomic Energy Industries Group (Japan)

    1964-04-15

    intended to study the influence of high temperature upon the reactor parameters. (author) [French] Les assemblages sous-critiques sont a uranium naturel et a graphite. L'assemblage qui fait l'objet du memoire est caracterise par une partie a haute temperature qui peut etre placee au centre d'assemblages a basse temperature, et peut fournit des renseignements a la fois pour le futur reacteur a haute temperature refroidi par un gaz et pour la conversion directe de l'energie d'un milieu gazeux a haute temperature en electricite. En outre, il est prevu qu'il sera utilise pour renseignement. L'assemblage a ete place dans une structure de 2 x 2 x 3 m, composee de manchons en graphite de barres carrees de 10 cm de cote. La partie a haute temperature, de 1 m3, est chauffee par effet Joule et peut etre maintenue a une temperature de 2000 Degree-Sign C. Pour la partie a basse temperature, on utilise comme combustible des pastilles d'UO{sub 2} , et pour la partie , a haute temperature, des pastilles d'UC{sub 2}. Le combustible est introduit dans les manchons en graphite de barres de section carree. Les sources Am-Be de 5 c sont placees sous le socle fixe a la base des assemblages; d'autre part, les neutrons puises sont injectes dans l'assemblage a un point pris arbitrairement. La cible placee a l'extremite d'un tube branche sur un accelerateur est bombardee par un faisceau de deutons. Les connexions du dispositif de chauffage par effet Joule sont refroidies a l'eau et l'ensemble de la surface des parios de la partie a haute temperature a l'helium. Les circuits d'helium a haute temperature sont concus de maniere a servir pour les travaux de recherche relatifs a la conversion directe. Ces assemblages sont equipes d'appareils de controle et de mesure comparables a ceux dont sont dotes les petits reacteurs nucleaires. L'auteur met au point une methode experimentale de determination du laplacien du systeme; il a cherche quelle est la meilleure disposition pour la source de neutrons puises

  9. L’évolution de l’affirmative action aux États-Unis sous la présidence de George W. Bush Evolution of Affirmative Action in the United States during the Presidency of George W. Bush

    Directory of Open Access Journals (Sweden)

    Marie-Christine Pauwels

    2010-03-01

    Full Text Available L’offensive contre l’affirmative action engagée depuis les années 1980 s’est accrue pendant les deux mandats de la présidence Bush, et l’opinion publique s’est radicalisée, percevant désormais de plus en plus fréquemment ces programmes comme une série d’avantages indûment octroyés à un certain nombre de « privilégiés ». Tout programme d’affirmative action doit désormais être étayé par des disparity studies démontrant la réalité de la discrimination, et seules des mesures très ciblées (narrowly tailored sont autorisées pour y remédier. La charge de la preuve a été en quelque sorte inversée. Mais contrairement aux idées reçues, l’affirmative action n’est pas sur le point de disparaître aux États-Unis et malgré son hostilité de principe, le gouvernement Bush n’a pris aucune mesure concrète pour démanteler ces programmes. L’affirmative action connaît aujourd’hui plusieurs transformations majeures, l’évolution la plus marquante étant l’effacement du critère ethno-racial au profit de critères plus neutres et moins idéologiquement polarisants, essentiellement d’ordre géographique et territorial. Dans l’enseignement supérieur par exemple, des procédures d’admission codées ont vu le jour pour favoriser l’accès des minorités ethniques sous-représentées aux campus d’élite, et diverses stratégies de contournement ont été mises en place dans l’adjudication des marchés publics. Ces transformations sont également intéressantes à analyser d’un point de vue transnational, puisque l’on observe une convergence croissante avec le modèle français de discrimination positive, lui aussi fondé sur le camouflage et l’euphémisation de l’identité ethno-raciale et sur une logique de territoire.This article examines the fate of affirmative action in the United States during the eight years of the Bush administration. After a brief reminder of the major landmarks

  10. Purification by high vacuum fusion and progressive solidification of uranium from electrolytic origin; Purification par fusion sous vide eleve et solidification progressive d'uranium d'origine electrolytique

    Energy Technology Data Exchange (ETDEWEB)

    Poeydomenge, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-01-15

    grain observed, so-called secondary recrystallisation. in appendix, the method for measuring the electrical resistance by induction (with direct current)is studied from the fundamental and experimental point of view. The author applied it to the particular case of uranium for measuring the low-temperature resistance of the bars from the same which solidified first to the least pure ended the ingot. (author) [French] Dans le cadre de recherches generales sur la purification de l'uranium par fusion de zone, on a entrepris de determiner le degre de purification que l'on pourrait atteindre par une simple solidification progressive a vitesse et direction soigneusement controlees d'un uranium de purete nucleaire courante. Cet uranium de purete intermediaire fournirait un materiau de depart approprie au mode de purification ultime qu'est la fusion a zone verticale, dite ''flottante''. Dans ce but, des lingots d'uranium d'origine electrolytique ont ete refondus sous vide (2 a 5 x 10{sup -6} mm) dans une longue nacelle en UO{sub 2} apres une monte lente en temperature pour eliminer le maximum de gaz et d'impuretes volatiles. Ce degazage et cette volatilisation d'impuretes sont completes par maintien prolonge a haute temperature du bais liquide. Celui-ci est ensuite solidifie d'une extremite a l'autre de la nacelle par deplacement a vitesse lente et constante du front de solidification de facon a obtenir une repartition des impuretes selon les lois etablies par PFANN. Differentes methodes experimentales ont permis de montrer que le metal solidifie en premier lieu est nettement plus pur que celui de la partie solidifie a l'extremite opposee du lingot. Le degre de purification du metal en tete du lingot a ete apprecie, soit quantitativement par mesure du rapport des resistivites electriques a la temperature ambiante et a celle de l'azote liquide, soit qualitativement par l'examen de la structure micrographique et par l'etude de la recristallisation du metal. D'une part, le metal

  11. La spirale dell’azzardo: una subcultura del gioco che “evapora” le relazioni / La spirale du jeu de hasard : une sous-culture qui empêche toute relation / The gambling: a subculture of game that “burns” the relationships

    Directory of Open Access Journals (Sweden)

    Molin Valentina

    2011-07-01

    neutralizzazione dei possibili rinforzi negativi che provengono invece dai “non-giocatori”.Dans cet article, l’auteur analyse les caractéristiques de ce qu’elle a appelé « sous-culture des jeux de hasard », décelable dans certains milieux de loisirs et dans les sous-groupes de joueurs particulièrement « acharnés ». Parmi ces formes de sous-culture, l’article va identifier les règles et les sanctions, les valeurs, les comportements durables, la caractérisation des relations et des interactions, en concluant que ce qui est construit dans l'espace du jeu est un univers séparé, une «réalité extérieure» dans laquelle des nouvelles règles sont écrites et où les valeurs changent par rapport au «monde extérieur» . Il a également été possible de conclure que l'adhésion à l' «univers du jeu» - l'internalisation de ses normes, le partage de ses valeurs, le développement des relations en son sein - est un facteur de maintenance de la conduite du jeu, car cette adhésion permet d'envisager comme «normal» son propre comportement grâce à des réactions positives provenant des compagnons de jeu et à la neutralisation d’éventuelles réactions négatives provenant des «non joueurs».

  12. Study of atmospheric tritium transfers in lettuce: kinetic study, equilibrium and organic incorporation during a continuous atmospheric exposure; Etude des transferts du tritium atmospherique chez la laitue: Etude cinetique, etat d'equilibre et integration du tritum sous forme organique lors d'une exposition atmospherique continue

    Energy Technology Data Exchange (ETDEWEB)

    Boyer, C.

    2009-11-30

    This thesis has explored the mechanisms of tritium 'absorption and incorporation in a human-consumed plant, lettuce (Lactuca sativa L.), due to atmospheric exposure. Foliar uptake appears to play a key role in absorption of tritium as tissue free water tritium. Whatever the development stage and the light conditions, the specific activity in tissue free water reaches that of water vapour in air in several hours. The specific activity ratio is then about 0, 4. The time to reach equilibrium in soil is over 24 hours in most cases: the specific activity ratio ranges then 0, 01 to 0, 26. Incorporation rate of tissue free water tritium as organically-bound tritium has been estimated to 0, 13 to 0, 16 % h-l in average over the growing period of the plant, but marked variations are observed during growth. In particular, a significant increase appeared at the exponential growth stage. Deposition and diffusion of tritium in soil lead to significant OBT activities in soil. Results globally indicate equilibrium between the different environmental compartments (air, soil, plant). However, some experiments have revealed high OBT concentrations regarding atmospheric level exposure and ask for a possible phenomenon of local tritium accumulation in OBT for particular conditions of exposure. (author) [French] Ce travail de these a concerne l'etude des phenomenes d'absorption et d'incorporation sous forme organique du tritium dans un vegetal de consommation courante, la laitue (Lactuca sativa L.), en reponse a une exposition atmospherique. Il apparait que la voie foliaire joue un role primordial dans l'absorption du tritium au sein de l'eau tissulaire des plants. Quels que soient le stade de developpement des plants et les conditions d'eclairement, le temps necessaire pour atteindre l'equilibre des concentrations dans l'eau libre et dans la vapeur d'eau de l'air est de plusieurs heures; le rapport des concentrations est alors de

  13. Soudage par explosion thermique sous charge de cermets poreux à base de TiC-Ni sur substrat en acier-comportement tribologique Welding of porous TiC–Ni based cermets on substrate steel by thermal explosion under load-tribological behaviour

    Directory of Open Access Journals (Sweden)

    Lemboub Samia

    2013-11-01

    Full Text Available Dans ce travail, nous nous intéressons à l'élaboration de cermets à base de TiC-Ni par dispersion de particules de carbures, oxydes ou borures dans une matrice de nickel, grâce à la technique de l'explosion thermique sous une charge de 20 MPa. La combustion de mélanges actifs (Ti-C-Ni-An où An = Al2O3, MgO, SiC, TiB2, WC, basée sur la réaction de synthèse de TiC (ΔHf298K = −184 kJ/mole, génère des cermets complexes. Un court maintien sous charge du cermet à 1373 K, après l'explosion thermique, permet son soudage sur un substrat en acier XC55. Les cermets obtenus dans ces conditions demeurent poreux et conservent une porosité de l'ordre de 25–35 %. La densité relative du cermet, sa dureté et son comportement tribologique, dépendront de la nature de l'addition dans les mélanges de départ. Porous TiC-Ni based cermets were obtained by dispersion of carbides, oxides or borides particles in a nickel matrix thanks to the thermal explosion technique realized under a load of 20 MPa. The combustion of active mixtures (Ti-C-Ni-An where An = Al2O3, MgO, SiC, TiB2 or WC based on the titanium carbide reaction synthesis (ΔHf = −184 kJ/mol, generates porous complex cermets. After the thermal explosion, a short maintenance under load at 1373 K of the combustion product, allows at the same time the cermets welding on a carbon steel substrate. The obtained cermets under these conditions preserve a porosity of about 25–35%. The relative density, hardness and tribological behaviour of the complex cermets depend on the additions nature (An in the starting mixtures.

  14. Application du concept de maillon faible à un critère d'endurance multiaxial

    Science.gov (United States)

    Flacelière, L.; Morel, F.; Palin-Luc, T.

    2002-12-01

    En fatigue à grand nombre de cycle, il est aujourd'hui admis que la distribution des contraintes, ainsi que la taille des composants, sont responsables de variations de la limite de fatigue. Sous chargement uniaxial ou multiaxial, on peut montrer qu'une approche statistique dite du maillon le plus faible, combiné à un critère multiaxial d'endurance basé sur une analyse micro plastique, permet de prédire la limite de fatigue de plusieurs matériaux métalliques. Quatre types de chargement sont analysés (traction-compression, torsion, flexion rotative et flexion plane), puis comparées aux résultats expérimentaux, pour une fonte et deux aciers haute résistance. L'approche statistique proposée permet d'intégrer un certain nombre d'aspects: la dispersion des données pour tous types de chargement, l'effet de gradient et l'influence de la présence de défauts matériaux. Enfin, ce modèle rend également compte de la diminution de la limite de fatigue avec l'augmentation du volume contraint. Les prédictions des probabilités de rupture sont raisonnables bien que seules des limites de fatigue relatives à des probabilités de rupture de 50% soient utilisées pour l'identification des paramètres du modèle.

  15. Radioactive study of Mo{sup 93} and Mo{sup 95} levels and research of subshell effects for the shell 2d 5/2; Etude, par radioactivite des niveaux de {sup 93}Mo et de {sup 95}Mo et essai de mise en evidence de la sous-couche 2d{sub 5/2}

    Energy Technology Data Exchange (ETDEWEB)

    Levi Lesueur, Ch [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1961-03-15

    We studied the decay schemes of Tc{sup 93} et Tc{sup 95} to determine the spins of Mo{sup 93} and M{sup 95} levels, and especially the position of the single-particle level 1g 7/2. We found a large spacing between the neutron shells 2d 5/2 and 1g 7/2 like that observed first in Mo{sup 97}. As the subshell 2d 5/2 is so far from its neighbours, we thought that subshell effects could perhaps be discovered in the systematics of separation energies and beta-decay energies. We found such effects. (author) [French] Par l'etude des schemas de desintegration de {sup 93}Tc et {sup 95}Tc, nous avons essaye de determiner les spins des niveaux de {sup 93}Mo et {sup 95}Mo et en particulier la position du niveau de particule 1g 7/2. Nous avons ainsi confirme l'ecart important entre les couches de neutrons 2d 5/2 et 1g 7/2 deja constate a propos de {sup 97}Mo. Nous avons pense que la sous-couche 2d 5/2 ainsi isolee des couches voisines pouvait, peut etre, etre mise en evidence par l'etude des systematiques d'energies de separation et d'energies de desintegration beta. Nous avons verifie qu'il en etait bien ainsi. (auteur)

  16. Fuel slugs considered for use in the high flux reactor EL3; Elements combustibles envisages pour la pile a haut flux EL 3

    Energy Technology Data Exchange (ETDEWEB)

    Stohr, J A; Caillat, R; Gauthron, M; Montagne, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    EL3 was designed essentially for the study, under irradiation conditions, of materials used in the construction of atomic reactors. The study schedule allocates considerable time and effort to new types of fuel slugs. The present report described the various types of slug being tested or scheduled for tests. After laboratory study, each slug is tested in an experimental cell in the pile. The best are retained and used to charge the reactor (the present charge is purely provisional to permit first criticality and power rise tests)ren. [French] La pile EL3 est essentiellement destinee a l'etude sous irradiation des materiaux utilises dans la construction des reacteurs atomiques. Dans ce programme, une tres large part est reservee a l'etude de nouveaux elements combustibles. Le present rapport decrit les differentes solutions de cartouches dont l'essai est envisage ou en cours. Apres etude en laboratoire, chacune de ces solutions est testee dans une cellule experimentale en pile. Les meilleures seront retenues pour constituer le chargement normal de la pile (le chargement actuel etant essentiellement une solution provisoire qui a permis la divergence de la pile et les premiers essais de montee en puissance). (auteur)

  17. Emo. Origini, significati e caratteristiche della “sottocultura delle emozioni” / Emo. Origines, significations et caractéristiques de la “sous-culture des émotions” / Emo movement. Origins, meanings and characteristics of the “emotions subculture”

    Directory of Open Access Journals (Sweden)

    Serafin G.

    2010-12-01

    Full Text Available Uno dei fenomeni giovanili, che oggi pare essere sempre più preoccupante, è quello degli “emo”. Sembra trattarsi di un movimento sottoculturale che, almeno inizialmente, muove i primi passi dal punk della fine degli anni ’70. Uno degli aspetti che caratterizza questa moderna subcultura giovanile di matrice gotica è dato da una filosofia di vita nichilista e dal ricorso all’autolesionismo. Il più delle volte si tratta di giovani e adolescenti con il bisogno di cercare una propria dimensione e che, come è facilmente intuibile dalla stessa parola “emo”, sono alla ricerca di emo-zioni.Con questo lavoro, che non pretende assolutamente di essere una esaustiva trattazione del fenomeno, si cerca di gettare alcune basi per lo studio e la comprensione di quello che sembra essere un sempre più diffuso sintomo di un disagio giovanile.L’analisi delle storie di vita di alcuni giovani emo dovrebbe, pertanto, consentire se non altro di fornire un inquadramento del movimento nei suoi tratti salienti. Un des phénomènes juvéniles qui aujourd'hui paraît être de plus en plus préoccupant est celui des « emo ». Il s’agit d'un mouvement sous-culturel qui, au moins initialement, remue les premiers pas du punk de la fin des années 70. Une philosophie de vie nihiliste et le recours à l’automutilation sont certains des aspects qui caractérisent cette sous-culture juvénile contemporaine de matrice gothique. Il s’agit le plus souvent de jeunes et d’adolescents qui ont besoin de trouver leur propre vie et qui sont – comme l’on peut deviner du même mot « emo » - à la recherche d'émo-tions.Cet article, qui ne prétend pas être une étude exhaustive du phénomène, essaye de jeter les bases pour l'analyse et la compréhension de ce qui semble être un symptôme d’un malaise juvénile de plus en plus diffusé.L'analyse des récits de vie de certains jeunes « emo » devrait, donc, permettre de fournir un encadrement du mouvement

  18. Research trends in radiobiology since 40 years. a new approach: the enzymatic repair function of DNA, internal factor in evolution of biological systems under irradiation; Etude des tendances des recherches en radiologie depuis 40 ans. Une nouvelle voie de recherche: la fonction de reparation enzymatique de l'ADN, facteur interne d'evolution des systemes biologiques sous rayonnement

    Energy Technology Data Exchange (ETDEWEB)

    Mouton, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    'on croyait encore que les effets des rayonnements sur les systemes vivants etaient des effets directs, immediats, irreparables et definitifs. Depuis lors, on s'est rendu compte que les radiolesions pouvaient resulter d'effets indirects, etre tardives, reparables, et le plus souvent modifiables par des traitements chimiques ou biochimiques ad hoc. Cependant, la percee decisive en radiobiologie se situe entre 1962 et 1964, avec la decouverte que la cellule possede un mecanisme de defense active vis-a-vis de tout ce qui peut porter atteinte a l'integrite du patrimoine genetique inscrit dans la structure meme de l'ADN. L'existence d'une quatrieme fonction de l'ADN, celle d'auto-reparation, par voie enzymatique sous controle genetique, apporte enfin a la radiobiologie la base biologique moleculaire qui lui manquait pour sortir de la nuit 'phenomenologique' ou elle s'etait enfoncee apres l'abandon de la generalisation de la theorie de Lea, faute de preuve experimentale. Dans la seconde partie, cette fois prospective, de l'etude l'auteur tente une synthese elargie en considerant le role que peut jouer cette fonction de reparation de l'ADN non seulement du point de vue de la survie des systemes biologiques irradies en presence ou non d'agents modificateurs de dose ou mutagenes, mais aussi de celui de l'evolution naturelle ou artificielle de ces systemes sous rayonnement. Les donnees les plus recentes de la litterature sont en accord avec ce qui ne constitue encore qu'une hypothese generale de recherche. Des travaux portant sur les caracteres phenotypiques et genotypiques lies a l'acquisition de radioresistance gamma et UV, chez 'Escherichia coli K12', ont ete entrepris par l'auteur, en collaboration avec O. Tremeau en vue d'apporter une contribution experimentale nouvelle a cet egard. (auteur)

  19. Comportement en vapocraquage de molécules modèles et de distillats sous vide hydrotraités. Première partie : potentialité de craquage, réacteur à profil de température rectangulaire et à court temps de séjour Steam-Cracking Behavior of Model Molecules and Hydrotreated Vacuum Distillates

    Directory of Open Access Journals (Sweden)

    Berthelin M.

    2006-11-01

    Full Text Available Dans le cadre de la valorisation des coupes lourdes par vapocraquage, des distillats sous vide plus ou moins hydrotraités et des molécules modèles ont été pyrolysés. Cette étude a été réalisée sur un micropilote dont la partie réactionnelle est chauffée entre 680 et 860°C, par induction électromagnétique haute fréquence; le débit total peut varier de 60 à 800 g/h avec une perte de charge inférieure à 0,3 bar. Deux réacteurs tubulaires spiralés de rapport surface/volume allant jusqu'à 2000 m-1 permettent d'atteindre des temps de séjour de 10 à 400 millisecondes. Un indice quantifiant l'aptitude de chaque molécule à produire de l'éthylène, du propylène et des composés lourds, a permis l'établissement d'une échelle de potentialité de craquage, permettant d'orienter les performances d'un catalyseur de prétraitement : optimisation de la consommation d'hydrogène, meilleure valorisation des charges lourdes lors du vapocraquage. Grâce au profil de température rectangulaire du micropilote, des gains très importants de rendements d'éthylène et une production très faible d'asphaltènes ont été mis en évidence par pyrolyse de distillats sous vide hydrotraités. L'importance primordiale de la température dans le couple température-temps de séjour a été confirmée. Within the framework of the upgrading of heavy cuts for steam cracking, more or less hydrotreated vacuum distillates and model molecules were pyrolyzed. This research was done in a micropilot plant in which the reaction section was heated to between 680 and 860°C by high-frequency electromagnetic induction. The total flow rate can vary from 60 to 800 g/h with a pressure drop of less than 0. 3 bar. Two spiral tubular reactors with a high surface/volume ratio of up to 2000 m-1 enable residence times of 10 to 400 milliseconds to be obtained. An index quantifying the capacity of each molecule to produce ethylene, propylene and heavy compounds was used

  20. Geopressure and Trap Integrity Predictions from 3-D Seismic Data: Case Study of the Greater Ughelli Depobelt, Niger Delta Pressions de pores et prévisions de l’intégrité des couvertures à partir de données sismiques 3D : le cas du grand sous-bassin d’Ughelli, Delta du Niger

    Directory of Open Access Journals (Sweden)

    Opara A.I.

    2012-05-01

    Full Text Available The deep drilling campaign in the Niger Delta has demonstrated the need for a detailed geopressure and trap integrity (drilling margin analysis as an integral and required step in prospect appraisal. Pre-drill pore pressure prediction from 3-D seismic data was carried out in the Greater Ughelli depobelt, Niger Delta basin to predict subsurface pressure regimes and further applied in the determination of hydrocarbon column height, reservoir continuity, fault seal and trap integrity. Results revealed that geopressured sedimentary formations are common within the more prolific deeper hydrocarbon reserves in the Niger Delta basin. The depth to top of mild geopressure (0.60 psi/ft ranges from about 10 000 ftss to over 30 000 ftss. The distribution of geopressures shows a well defined trend with depth to top of geopressures increasing towards the central part of the basin. This variation in the depth of top of geopressures in the area is believed to be related to faulting and shale diapirism, with top of geopressures becoming shallow with shale diapirism and deep with sedimentation. Post-depositional faulting is believed to have controlled the configuration of the geopressure surface and has played later roles in modifying the present day depth to top of geopressures. In general, geopressure in this area is often associated with simple rollover structures bounded by growth faults, especially at the hanging walls, while hydrostatic pressures were observed in areas with k-faults and collapsed crested structures. Les campagnes de forages profonds dans le delta du Niger ont démontré la nécessité d’une analyse détaillée des surpressions et de l’intégrité des structures pour évaluer correctement les prospects. La prédiction des pressions interstitielles a pu être réalisée ici avant forage à partir de données sismiques 3-D du grand sous-bassin d’Ughelli, dans le delta du Niger. Ce travail a permis de prévoir les régimes de pression du

  1. Disposal of Radioactive Waste in the Subsurface of the Federal Republic of Germany: Geological and Hydro-Geological Problems; Elimination des Dechets Radioactifs dans le Sous-Sol de la Republique Federale d'Allemagne: Problemes Geologiques et Hydrogeologiques; 041f 041e 0414 ; Evacuacion de Desechos Radiactivos en el Subsuelo de la Republica Federal de Alemania Problemas Geologicos e Hidrogeologicos

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, R.; Richter, W. [Bundesanstalt fuer Bodenforschung, Hannover (Germany)

    1960-07-01

    The geological and hydrogeological problems related to the subsurface disposal of radioactive wastes in the Federal Republic of Germany are outlined. Special consideration is given to the possibility of storing solid and liquid wastes in the salt-domes widespread in the north-west, and of injecting liquid waste into deep reservoirs containing briny water and located in favourable geologic structures. (author) [French] Les auteurs decrivent les problemes geologiques et hydrogeologiques que pose, dans la Republique federale d'Allemagne, l'elimination des dechets radioactifs dans le sous-sol. Ils examinent notamment la possibilite d'emmagasiner des dechets solides et liquides dans les salines, qui abondent dans la partie nord-ouest et d'injecter des dechets liquides dans de profonds reservoirs d'eau saline, situes dans des formations geologiques presentant des conditions favorables. (author) [Spanish] Los autores exponen los problemas geologicos e hidrogeologicos que plantea la evacuacion de desechos radiactivos en el subsuelo de la Republica Federal de Alemania. Examinan sobre todo la posibilidad de almacenar desechos solidos y liquidos en los domos de sal, muy abundantes en el noroeste del pais, y de inyectar desechos liquidos en depositos profundos de agua salobre situados en estructuras geologicas que presentan condiciones favorables. (author) [Russian] Privoditsja opisanie geologicheskih i gidrogeologicheskih problem, svjazannyh s podzemnym udaleniem radioaktivnyh othodov v Federal'noj Respublike Germanii. Osoboe vnimanie udeljaetsja vozmozhnosti skladirovanija tverdyh i zhidkih othodov v soljanyh kupolah, imejushhihsja v bol'shom kolichestve v severo- zapadnoj chasti Germanii, i zahoronenija zhidkih othodov v glubokie rezervuary, soderzhashhie solenye vody i raspolozhennye v podhodjashhih geologicheskih strukturah. (author)

  2. Theoretical aspects of neutron interaction: part 1 - interaction programme for ibm 7094, part 2 - the shielding sub-programme, part 3 - listing of the programme; Aspects theoriques de l'interaction neutronique: annexe 1 - programme interaction pour ibm 7094 - annexe 2 - sous programme ombre - annexe 3 - liste du programme

    Energy Technology Data Exchange (ETDEWEB)

    Moret-Bailly, J; Penet, F; Spinelli, J C [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    Part I. Methods are described for obtaining the equations for a system of elements containing fissile matter: a) by using the balance after fission, b) by using the balance before fission, c) by the evolution equations. All these methods lead to equivalent matrices whose greatest proper value is the multiplication coefficient for the system K. It is shown how to calculate K. From this it is possible to deduce the rules which generalize the criterion for the bounded solid angle. An IBM 7094 programme applies this theory to the calculation of the installations made up of a maximum of 500 elements. It calculates the effective values of K, the leaks, the solid angles and then K. Part. II. This sub-programme calculates the shielding between the elements. (authors) [French] Sommaire, - Annexe I. On expose les methodes permettant d'obtenir les equations d'un systeme d'elements contenant de la matiere fissile: a) par le bilan apres fission, b) par le bilan avant fission, c) par les equations d'evolution. Toutes ces methodes conduisent a des matrices equivalentes dont la plus grande valeur propre est le coefficient de multiplication de l'ensemble K. On montre comment K se calcule. On en deduit des regles qui generalisent le critere de l'angle solide limite. Un programme pour IBM 7094 applique cette theorie au calcul des installations comportant au maximum 500 elements. II calcule les k effectifs, les fuites, les angles solides puis K. Annexe II. Ce sous-programme calcule les ombres entre les elements. (auteurs)

  3. Construction, Cost and Use of an Enriched Uranium, Light-Water Subcritical Assembly; Assemblage Sous-Critique a Uranium Enrichi et Eau Legere; Realisation, Cout et Application; Realizatsiya i stoimost' podkriticheskoj sborki na obogashchennom urane i legkoj vode; Construccion, Coste y Aplicacion de un Conjunto Subcritico de Uranio Enriquecido

    Energy Technology Data Exchange (ETDEWEB)

    Vittoz, B.; Berthet, P.; Gavin, P.; Mandrin, C.; Robert, P.; Thurnheer, J. [Ecole Polytechnique de l' Universite de Lausanne (Switzerland)

    1964-02-15

    Designed for the experimental investigation of multiplying lattices, the Lausanne subcritical assembly is also used for teaching purposes. It is extremely versatile. The authors explain why the Nuclear Engineering Laboratory of the Ecole Polytechnique, University of Lausanne, decided to construct a subcritical assembly, relying as far as possible on its own resources, and why a slightly enriched uranium, light-water lattice was selected. The construction and arrangements are such that the lattice and neutron input parameters can be varied quickly and easily. 1. The uranium rods are vertically suspended and each suspension point has two degrees of freedom and can be continuously varied. Hence the lattice spacing, for example, can also be continuously varied. 2. The neutron input is provided by five Pu-Be sources placed in a graphite base. The spacing of these sources can also be continuously regulated. The paper discusses the safety problems the facility involves because of the fact that the reactivity can vary a great deal from one configuration to the other. It also explains the general construction and operational costs. The facility is used, inter alia, to study a non-periodic lattice with a view to obtaining a uniform flux. For this purpose the heterogeneous theory developed by Feinberg and Horning is used. A lattice in which the rods are identically arranged in non-equidistant, parallel n-planes is first considered. Each plane is a fast- neutron source and an absorber of thermal neutrons. Outside these planes, two-group diffusion equations are used. If the characteristics of a single plane are known the neutron flux for the n- planes can be forecast. These characteristics are determined experimentally, with due regard to the vertical variation of the neutron flux. The role played by the distance between the rods in a given plane is also investigated. (author) [French] Destine a l'etude experimentale des reseaux ienultiplicateurs, l'assemblage sous-critique de

  4. Present Status of Nitrogen Fixation by Reactor Radiation; Etat Actuel des Recherches sur l'oxydation directe de l'azote sous irradiation dans des reacteurs; Sovremennoe sostoyani opytov po okisleniyu azota izlucheniem iz reaktorov; Estado actual de las investigaciones sobre fijacion del nitrogeno por irradiacion en reactores

    Energy Technology Data Exchange (ETDEWEB)

    Harteck, P; Dondes, S [Rensselaer Polytechnic Institute, Troy, NY (United States)

    1960-07-15

    'oxydation directe de l'azote sous irradiation, entreprises depuis plusieurs annees par le Rensselaer Polytechnic Institute et le Brookhaven National Laboratory, utilisent directement les particules de recul de fission comme rayonnements ionisants, au moyen de la dispersion d'uranium-235 dans des fibres de verre de cinq microns de diametre environ. Les auteurs ont determine les effets de la temperature, de la pression et du rapport azote/oxygene sur la valeur de G pour l'oxydation de l'azote et ont publie le compte rendu de leurs travaux. Ils en donnent un bref apercu. Les recherches en question ont ete effectuees avec des systemes statiques; plus recemment des systemes statiques et des systemes a circulation ont ete utilises a la fois. Avec les systemes statiques, les auteurs se sont surtout attaches a etudier l'effet de l'intensite des rayonnements, notamment sur la cinetique d'equilibre sous irradiation. Ils ont constate que dans des melanges ou le rapport azote/oxygene est de 4 a 1 et de 2 a 1 N0{sub 2} et N{sub 2}0 se forment jusqu'a epuisement de tout l'oxygene present. Un systeme a circulation continue (cycling) fonctionne maintenant dans une boucle a l'interieur du reacteur de Brookhaven. Les auteurs fournissent sur les effets de la temperature, de la pression, du rapport azote/oxygene et de l'intensite des rayonnements des donnees que l'on pourra utiliser pour etablir un projet de reacteur de chimie nucleaire. Le systeme actuel fonctionne sous 10 atmospheres et a 150{sup o}C. La temperature est fonction de l'energie de fission liberee dans les fibres de verre et de la resistance thermique du circuit. Une autre boucle, qui doit fonctionner sous 50 - 75 atmospheres et a 600{sup o} C, est en construction. Il est possible, grace a ces boucles, d'etudier les caracteristiques d'un systeme continu, y compris le comportement des produits de fission liberes dans le courant, gazeux. Les auteurs distinguent trois stades dans la cinetique complexe de l'oxydation de l'azote: reactions

  5. Organisation of biological research carried out in the United States by the A.E.C. or under her contract (1960); Organisation des recherches biologiques menees aux Etats-Unis par l'A.E.C. ou sous son egide. Compte-rendu sommaire d'une mission d'etude (1960)

    Energy Technology Data Exchange (ETDEWEB)

    Pellerin, J [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    This report is based on information gathered in the course of a trip to the United States, in November and December 1958 which consisted chiefly of visits to the main biological and medical research laboratories and discussions with the heads of these establishments. A description is given of the general organisation of the Atomic Energy Commission's Division of Biology and Medicine, and of the distribution of responsibility for radiation protection work and for biological, medical and agricultural research amongst the various Services attached to it; this is followed by a more detailed account of the activities carried on in this field at the great national laboratories. Finally, the systems of collaboration set up with external research organisations in the form of research contracts are examined, together with the substantial help provided by the A.E.C. for biological, medical and agricultural research in general, owing to a systematic policy of subsidising the distribution of radioisotopes for this purpose. (author) [French] Le present rapport a ete etabli sur la base des renseignements recueillis au cours d'un voyage d'etude aux Etats-Unis, en novembre et decembre 1958, comportant notamment la visite des principaux laboratoires de recherche biologique et medicale et des entretiens avec les principaux responsables de ces laboratoires. Apres une description de l'organisation generale de la 'Division of Biology and Medicine' de l'Atomic Energy Commission et de la repartition entre les divers Services qui lui sont rattaches des responsabilites concernant la protection contre les radiations et la Recherche biologique, medicale et agronomique, des indications plus detaillees sont donnees au sujet des activites poursuivies dans ce domaine au sein des grands laboratoires nationaux. Sont examinees enfin, l'importance et les modalites de la collaboration instituee avec les Organismes de Recherche exterieurs sous la forme de contrats de recherche ainsi que l

  6. Organisation of biological research carried out in the United States by the A.E.C. or under her contract (1960); Organisation des recherches biologiques menees aux Etats-Unis par l'A.E.C. ou sous son egide. Compte-rendu sommaire d'une mission d'etude (1960)

    Energy Technology Data Exchange (ETDEWEB)

    Pellerin, J. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    This report is based on information gathered in the course of a trip to the United States, in November and December 1958 which consisted chiefly of visits to the main biological and medical research laboratories and discussions with the heads of these establishments. A description is given of the general organisation of the Atomic Energy Commission's Division of Biology and Medicine, and of the distribution of responsibility for radiation protection work and for biological, medical and agricultural research amongst the various Services attached to it; this is followed by a more detailed account of the activities carried on in this field at the great national laboratories. Finally, the systems of collaboration set up with external research organisations in the form of research contracts are examined, together with the substantial help provided by the A.E.C. for biological, medical and agricultural research in general, owing to a systematic policy of subsidising the distribution of radioisotopes for this purpose. (author) [French] Le present rapport a ete etabli sur la base des renseignements recueillis au cours d'un voyage d'etude aux Etats-Unis, en novembre et decembre 1958, comportant notamment la visite des principaux laboratoires de recherche biologique et medicale et des entretiens avec les principaux responsables de ces laboratoires. Apres une description de l'organisation generale de la 'Division of Biology and Medicine' de l'Atomic Energy Commission et de la repartition entre les divers Services qui lui sont rattaches des responsabilites concernant la protection contre les radiations et la Recherche biologique, medicale et agronomique, des indications plus detaillees sont donnees au sujet des activites poursuivies dans ce domaine au sein des grands laboratoires nationaux. Sont examinees enfin, l'importance et les modalites de la collaboration instituee avec les Organismes de Recherche exterieurs sous la forme de

  7. Research trends in radiobiology since 40 years. a new approach: the enzymatic repair function of DNA, internal factor in evolution of biological systems under irradiation; Etude des tendances des recherches en radiologie depuis 40 ans. Une nouvelle voie de recherche: la fonction de reparation enzymatique de l'ADN, facteur interne d'evolution des systemes biologiques sous rayonnement

    Energy Technology Data Exchange (ETDEWEB)

    Mouton, R. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    . Il y a moins d'une generation, l'on croyait encore que les effets des rayonnements sur les systemes vivants etaient des effets directs, immediats, irreparables et definitifs. Depuis lors, on s'est rendu compte que les radiolesions pouvaient resulter d'effets indirects, etre tardives, reparables, et le plus souvent modifiables par des traitements chimiques ou biochimiques ad hoc. Cependant, la percee decisive en radiobiologie se situe entre 1962 et 1964, avec la decouverte que la cellule possede un mecanisme de defense active vis-a-vis de tout ce qui peut porter atteinte a l'integrite du patrimoine genetique inscrit dans la structure meme de l'ADN. L'existence d'une quatrieme fonction de l'ADN, celle d'auto-reparation, par voie enzymatique sous controle genetique, apporte enfin a la radiobiologie la base biologique moleculaire qui lui manquait pour sortir de la nuit 'phenomenologique' ou elle s'etait enfoncee apres l'abandon de la generalisation de la theorie de Lea, faute de preuve experimentale. Dans la seconde partie, cette fois prospective, de l'etude l'auteur tente une synthese elargie en considerant le role que peut jouer cette fonction de reparation de l'ADN non seulement du point de vue de la survie des systemes biologiques irradies en presence ou non d'agents modificateurs de dose ou mutagenes, mais aussi de celui de l'evolution naturelle ou artificielle de ces systemes sous rayonnement. Les donnees les plus recentes de la litterature sont en accord avec ce qui ne constitue encore qu'une hypothese generale de recherche. Des travaux portant sur les caracteres phenotypiques et genotypiques lies a l'acquisition de radioresistance gamma et UV, chez 'Escherichia coli K12', ont ete entrepris par l'auteur, en collaboration avec O. Tremeau en vue d'apporter une contribution experimentale nouvelle a cet egard. (auteur)

  8. Sous type rare du cancer de prostate: Le carcinome sarcomatoide

    African Journals Online (AJOL)

    A. Qarro

    est essentiellement chirurgical qui peut aller de la simple résection de la prostate jusqu'à l'exentération pelvienne associée ou non à la chimiothérapie ou à la radiothérapie. Le pronostic est très mauvais avec 20% de risque de décès la première année qui suit le diagnostic. Nous rapportons une observation d'un patient.

  9. Echanges thermiques dans un four à combustible eau sous ...

    African Journals Online (AJOL)

    Belonging to the class of the diffusive phenomena, these thermal transfers were explained using mathematical techniques among which transformations of Fourier and Laplace.. Concurrently to these theoretical aspects, the phenomena of transfers of heat intervene in an eminent way in the industrial activities and the life of ...

  10. Le CERN sous haute sécurité

    CERN Multimedia

    Scappaticci, Bruno

    2008-01-01

    1500 prestigious guests came to participate to the LHC inauguration on last Tuedday, among which the Swiss President and the French Prime Minister François Fillon. Picked unities of the polices (Swiss an French) were on a war-footing.. (2 pages)

  11. Les agendas 21 locaux : quels apports sous quelles latitudes ?

    Directory of Open Access Journals (Sweden)

    Cyria Emelianoff

    2005-05-01

    Full Text Available Since the Rio conference, several thousands local agendas 21 have assisted the penetration of the concept of sustainable development at the local level. This article presents a synthesis of the approaches employed by local authorities in 9 European countries, with an emphasis on the benefits and limitations presented by the local agendas 21 in place. We characterised the specificities of French local authorities and determined the geographical dimensions of the mobilisation in favour of local agendas 21.

  12. De vieilles obsessions sous des habits neufs ?

    Directory of Open Access Journals (Sweden)

    Louis Quéré

    2011-10-01

    Full Text Available Cet article fait le tri dans le texte de Laurence Kaufmann et Laurent Cordonier entre ce qui paraît et ce qui ne paraît pas plausible dans leurs conjectures. Il spécifie à quelles conditions on peut admettre l'hypothèse du « cerveau social ». Il est par contre plus critique à l'égard de l'idée d'une « régulation neuroendocrinienne du lien social ». L'argument est que les auteurs n'estiment pas correctement les possibilités et les limites des explications neuroscientifiques des conduites humaines et des relations sociales. Enfin l'article confronte la forme de naturalisme social défendue par les auteurs à celle de la tradition pragmatiste (John Dewey et George Herbert Mead et s'appuie sur la seconde pour faire ressortir le caractère problématique de la première.A new look for old obsessions?This paper tries to sift out the plausible in what Laurence Kaufmann and Laurent Cordonier tell in their article. It specifies some conditions for the acceptation of their surmise about the « social brain ». It criticizes much more their speculations about a « neuroendocrinous regulation of the social bond ». It argues that the authors don't estimate properly the capacities and the limits of the neuroscientific explanations of human conduct and social relations. Finally, it compares the version of social naturalism assumed by the authors with the pragmatist tradition's one (John Dewey and George Herbert Mead and uses this last to show the problematic character of the first.¿Nuevas apariencias de añejas obsesiones?El autor pasa por la criba el texto de Laurence Kaufman y Laurent Cordonier y distingue entre lo que parece plausible y lo que no lo es. Específica bajo qué condiciones puede admitirse la hipótesis de un « cerebro social ». Es mucho más crítico con respecto a la « regulación neuro-endocrina de los lazos sociales ». Estos autores no analizan correctamente las posibilidades y los límites de las explicaciones neuro-científicas del comportamiento humano y de las relaciones sociales. El autor también confronta la forma de naturalismo social defendida por los autores con la de la tradición pragmatista (John Dewey y George Herbert Mead apoyándose en este último para resaltar el carácter problemático de la primera.

  13. Les formes psychiatriques des hematomes sous-duraux chroniques ...

    African Journals Online (AJOL)

    Methods: This was a retrospective study of 26 cases of chronic subdural hematoma with psychiatric disorders admitted in neurology, neurosurgery and psychiatry of Hôpital Général de Grand Yoff and Fann's CHU of Dakar (Senegal) between 2001 in 2009. Results: The mean age of patients was 80.6 years. No patient had a ...

  14. Les objets sous contrainte. Gages, saisies, confiscation, vol, pillage, recel…

    Directory of Open Access Journals (Sweden)

    Laurent Feller

    2009-09-01

    Full Text Available Cette table ronde s’inscrit dans le cadre d’une réflexion menée sur la valeur des choses au Moyen Âge, c’est-à-dire sur les conditions empiriques et théoriques de l’évaluation ; un groupe de travail conjoint du LAMOP (UMR 8589, Paris 1-CNRS et du CSIC de Madrid organise une série de tables rondes. La première s’est tenue à Madrid en novembre 2008 et a eu comme thème : « Circulation et remploi des objets au Moyen Âge ».Les objets circulent parfois malgré la volonté de leurs propriétaires, en ...

  15. Carcinome adenoide kystique sous-glottique | Gassab | Journal ...

    African Journals Online (AJOL)

    Case report: A 75-year-old man, presented with a laryngeal dyspnea. The computed tomography of the larynx showed a posterior subglottic tumor. The panendoscopy revealed a large nonulcerated submucosal tumor in the posterior wall of the subglottic area. Biopsies made the diagnosis of laryngeal ACC. The patient had ...

  16. Pia Petersen sous le signe de don Quichotte

    Directory of Open Access Journals (Sweden)

    Esther Bautista Naranjo

    2013-04-01

    Full Text Available This interview has been motivated by the Cervantean intertextuality of Pia Petersen’s (a French-speaking Danish author last novel, Le Chien de don Quichotte (2012. Departing from the values that the writer attributes to Cervantes’ work, I try to establish a connection with a specific critical trend in order to test, later on, to which extent this approach is used by the author to create a series of characters placed under the sign of don Quixote. Finally, I evaluate her novel’s relation with contemporary reality.

  17. Machine for extrusion under vacuum; Machine de fluage sous vide

    Energy Technology Data Exchange (ETDEWEB)

    Gautier, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    In a study of the behaviour of easily oxidised metals during the extrusion process, it is first necessary to find an effective mean of fighting corrosion, since this, even when barely detectable, has an important influence on the validity of the results recorded. The neatest and also the most efficient of all the methods tried consists in creating a vacuum around the test piece. Working on this principle, and at the same time respecting the conventional rules for extrusion tests (loading the sample after stabilisation at the testing temperature, differential measurements of lengthening, etc.) we found it necessary to construct an original machine. (author) [French] L'etude du comportement au fluage des materiaux facilement oxydables exige, en premier lieu, une lutte efficace contre la corrosion qui, meme a peine decelable, prend une part preponderante quant a la validite des resultats enregistres. La solution la plus elegante, et, a vrai dire, la plus energique parmi toutes les methodes essayees, consiste a realiser le vide autour de l'eprouvette d'essai. Partant de ce principe, et pour sauvegarder les regles classiques de l'essai de fluage (mise en charge de l'eprouvette apres stabilisation en temperature d'essai, mesures differentielles des allongements, etc.) nous nous sommes trouves dans la necessite de construire une machine inedite. (auteur)

  18. Machine for extrusion under vacuum; Machine de fluage sous vide

    Energy Technology Data Exchange (ETDEWEB)

    Gautier, A. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    In a study of the behaviour of easily oxidised metals during the extrusion process, it is first necessary to find an effective mean of fighting corrosion, since this, even when barely detectable, has an important influence on the validity of the results recorded. The neatest and also the most efficient of all the methods tried consists in creating a vacuum around the test piece. Working on this principle, and at the same time respecting the conventional rules for extrusion tests (loading the sample after stabilisation at the testing temperature, differential measurements of lengthening, etc.) we found it necessary to construct an original machine. (author) [French] L'etude du comportement au fluage des materiaux facilement oxydables exige, en premier lieu, une lutte efficace contre la corrosion qui, meme a peine decelable, prend une part preponderante quant a la validite des resultats enregistres. La solution la plus elegante, et, a vrai dire, la plus energique parmi toutes les methodes essayees, consiste a realiser le vide autour de l'eprouvette d'essai. Partant de ce principe, et pour sauvegarder les regles classiques de l'essai de fluage (mise en charge de l'eprouvette apres stabilisation en temperature d'essai, mesures differentielles des allongements, etc.) nous nous sommes trouves dans la necessite de construire une machine inedite. (auteur)

  19. Irradiation damage 'displacement zone'; Dommages sous irradiation zone de deplacements

    Energy Technology Data Exchange (ETDEWEB)

    Genthon, J P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1969-07-01

    It is well known that a charged particle (ion, primary atom, etc...) moving in a solid slows down and can cause a cascade of displacements of the atoms in the solid. A study is made here of the extent to which the cascade is made up, or not, of independent collisions, as a function of the energy of the initial charged particle. When the distance between the collisions is small, these latter are no longer independent; the cascade, which then has to be considered as a whole, perturbs and locates, in the irradiated solid , a zone which has been named a 'displacement zone'. It is shown that the proportion of displacement zones increases with increasing atom size (high atomic number Z), with decreasing atomic distance D in the substance considered and with decreasing energy of the ion undergoing the slowing down process (although always remaining above a few hundred eV). The proportions obtained are higher than those corresponding to the calculations of J. A. Brinkman [3]. An interatomic potential required for this work has also been determined. (author) [French] On sait qu'une particule chargee (ions, atomes primaires, etc...) en mouvement dans un solide se ralentit, avec eventuellement deplacement en cascade d'atomes du solide. On etudie ici dans quelle proportion, en fonction de l'energie de la particule chargee initiale, la cascade est constituee, ou non, de 'chocs independants'. Lorsque la distance entre chocs est petite, ceux-ci ne sont plus independants; la cascade, qui doit alors etre consideree dans son ensemble, perturbe et definit dans le solide irradie, une zone qu'on a appele zone de deplacements. On montre que la proportion de zones de deplacements est d'autant plus grande que les atomes sont gros (nombre atomique Z grand), que la distance interatomique D est petite dans le corps considere, et que l'energie de l'ion en ralentissement est petite (tout en restant superieure a quelques centaines d'eV). Les proportions obtenues sont superieures a celles qui correspondraient aux calculs de J. A. BRINKMAN [3], On determine d'autre part un potentiel interatomique, necessaire a cette etude. (auteur)

  20. Emissions under reinforced supervision; Des emissions sous surveillance renforcee

    Energy Technology Data Exchange (ETDEWEB)

    Remoue, A

    2009-11-15

    Despite some enforcement difficulties, the Integrated Pollution Prevention and Control (IPPC) European directive on the integrated approach of pollution is going to harden. The new version, which will be presented on second lecture at the Parliament in the beginning of 2010 will oblige industries to opt for the best available technologies. In Europe, 55000 sites are concerned by the IPPC directive, among which 6760 are in France. Today, about 1650 French sites are not in order with this directive. (J.S.)

  1. Biaxial nematic liquid crystals theory, simulation and experiment

    CERN Document Server

    Luckhurst, Geoffrey R

    2015-01-01

    Liquid Crystals are a state of matter that have properties between those of conventional liquid and those of a solid crystal. Thermotropic liquid crystals react to changes in temperature or, in some cases, pressure. The reaction of lyotropic liquid crystals, which are used in the manufacture of soaps and detergents, depends on the type of solvent they are mixed with. Since the accidental discovery of the chiral nematic (ordered) phase in 1888 many liquid crystal phases have been found, sometimes by chance and sometimes by design. The existence of one such phase was predicted by Freiser in 197

  2. Uniaxial and biaxial mechanical properties of porcine linea alba

    NARCIS (Netherlands)

    Cooney, Gerard M.; Moerman, Kevin M.; Takaza, Michael; Winter, Des C.; Simms, Ciaran K.

    2015-01-01

    Incisional hernia is a severe complication post-laparoscopic/laparotomy surgery that is commonly associated with the linea alba. However, the few studies on the mechanical properties of the linea alba in the literature appear contradictory, possible due to challenges with the physical dimensions of

  3. evaluation of approximate design procedures for biaxially loaded

    African Journals Online (AJOL)

    The approximation according to the ACI is based on the work by Parme [9] who chose to approximate a as a logarithmic function 9f a parameter /3 representing an actual point on· the non-dimensional load contour, where the two moment components, . related to the respective uniaxial capacities are equal,. i.e. f3=;: my lmuy ...

  4. Measurement of refractive index of biaxial potassium titanyl ...

    Indian Academy of Sciences (India)

    By this technique the change in polarization of light that is incident on a material ... threshold and non-hygroscopic nature shows its superiority over many nonlinear ... intensity vs. angle of analyzer whereas eqs (6) and (7) are the desired ...

  5. In-situ neutron diffraction during biaxial deformation

    International Nuclear Information System (INIS)

    Van Petegem, S.; Wagner, J.; Panzner, T.; Upadhyay, M.V.; Trang, T.T.T.; Van Swygenhoven, H.

    2016-01-01

    A change in strain path may have a significant effect on the mechanical response of metals. In order to understand or even predict the macroscopic behaviour under such conditions a detailed knowledge on the microstructural evolution is crucial. Yet relatively little work has been done to quantify and understand how the inter- and intragranular strains are affected during a change in strain path. In this work we present a new multiaxial deformation rig that allows performing in situ proportional and non-proportional loading under neutron diffraction. We demonstrate the capabilities of this new setup for the case of a 316 L stainless steel. We show that the nature and magnitude of intergranular strain strongly depends on the applied stress state and demonstrate that micro yielding and internal strain recovery are responsible for the observed transient softening during a 90° strain path change. We anticipate that this new characterization method will provide previously inaccessible microstructural data that can serve as input for benchmarking current state-of-the-art crystal plasticity models.

  6. In-situ neutron diffraction during biaxial deformation

    OpenAIRE

    Van Petegem, S.; Wagner, J.; Panzner, T.; Upadhyay, M.V.; Trang, T.T.T.; Van Swygenhoven, H.

    2016-01-01

    A change in strain path may have a significant effect on the mechanical response of metals. In order to understand or even predict the macroscopic behaviour under such conditions a detailed knowledge on the microstructural evolution is crucial. Yet relatively little work has been done to quantify and understand how the inter- and intragranular strains are affected during a change in strain path. In this work we present a new multiaxial deformation rig that allows performing in situ proportion...

  7. Numerical analysis of interacting cracks in biaxial stress field

    International Nuclear Information System (INIS)

    Kovac, M.; Cizelj, L.

    1999-01-01

    The stress corrosion cracks as seen for example in PWR steam generator tubing made of Inconel 600 usually produce highly irregular kinked and branched crack patterns. Crack initialization and propagation depends on stress state underlying the crack pattern. Numerical analysis (such as finite element method) of interacting kinked and branched cracks can provide accurate solutions. This paper discusses the use of general-purpose finite element code ABAQUS for evaluating stress fields at crack tips of interacting complex cracks. The results obtained showed reasonable agreement with the reference solutions and confirmed use of finite elements in such class of problems.(author)

  8. Biaxial nominal state of stress at the crack front

    International Nuclear Information System (INIS)

    Dietmann, H.; Kussmaul, K.

    1979-01-01

    In fracture toughness testing with CT-specimens there is an unaxial nominal stress state caused by the nominal stress psub(y) perpendicular to the crack surface. This paper investigates the question whether the fracture toughness, or generally speaking, the fracture load, is influenced by additional nominal stresses psub(x) and psub(z) in the crack surface, i.e. by a multiaxial stress state. (orig.)

  9. BEGA-a biaxial excitation Generator for automobiles

    DEFF Research Database (Denmark)

    Scridon, S.; Boldea, Ion; Tutelea, L.

    2005-01-01

    -voltage regulation is obtained by the flux-barrier PM combination with field (excitation) low-power control and a full-power diode rectifier in the stator. Good power/volume and superior efficiency (up to 80%) are obtained at costs comparable to those of an existing Lundell generator. The generator configuration...

  10. Biaxiality in Nematic and Smectic Liquid Crystals. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Satyendra [Kent State Univ., Kent, OH (United States); Li, Quan [Kent State Univ., Kent, OH (United States); Srinivasarao, Mohan [Georgia Inst. of Technology, Atlanta, GA (United States); Agra-Kooijman, Dena M. [Kent State Univ., Kent, OH (United States); Rey, Alejandro [McGill Univ., Montreal, QC (Canada)

    2017-01-24

    During the award period, the project team explored several phenomena in a diverse group of soft condensed matter systems. These include understanding of the structure of the newly discovered twist-bend nematic phase, solving the mystery of de Vries smectic phases, probing of interesting associations and defect structures in chromonic liquid crystalline systems, dispersions of ferroelectric nanoparticles in smectic liquid crystals, investigations of newly synthesized light sensitive and energy harvesting materials with highly desirable transport properties. Our findings are summarized in the following report followed by a list of 36 publications and 37 conference presentations. We achieved this with the support of Basic Sciences Division of the US DOE for which we are thankful.

  11. Comparison of fission probabilities with emission of long range particles under the action of slow and fast neutrons on various materials; Probabilites comparees de fission avec emission de particules de long parcours pour divers materiaux sous l'action des neutrons lents et rapides

    Energy Technology Data Exchange (ETDEWEB)

    Netter, F; Faraggi, H; Garin-Bonnet, A; Julien, J; Corge, C [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Turkiewicz, J [Institut de Recherches Nucleaire de Varsovie (Poland)

    1958-07-01

    parcours, sous l'action de neutrons de diverses energies: neutrons thermiques, neutrons de pile, neutrons produits avec l'accelerateur Van de Graaff par la reaction des protons sur le tritium. Les mesures sont effectuees: 1) a l'aide de plaques photographiques, en soumettant a l'action des neutrons une couche de matiere fissile, accolee contre une emulsion nucleaire Ilford de 100 microns; une feuille d'etain appliquee entre la plaque et la couche arrete les {alpha} et les fragments de fission. On distingue dans l'emulsion par un developpement approprie les trajectoires de particules de long parcours des trajectoires de protons de recul provenant soit des neutrons de fission, soit des neutrons primaires rapides. La frequence comparee des trajectoires des particules de long parcours et des reculs dus aux neutrons de fission fournit une mesure de la section efficace de fission avec emission de particules de long parcours relativement au produit de la section efficace de fission par le nombre moyen de neutrons emis par fission. Des precautions sont prises peur eliminer le role des neutrons thermiques dans les mesures par neutrons rapides. 2) a l'aide d'un systeme de chambre d'ionisation et compteur proportionnel, on mesure le taux de coincidence entre les impulsions produites par la particule de long parcours et celles produites par un des fragments de fission, relativement au taux de comptage des fragments de fission. (auteur)

  12. The Co{sup 60} Irradiation Facility and the Gamma Field at Riso; Appareil d'irradiation au cobalt-60 et champ sous irradiation gamma, a Riso; Ustanovka dlya obluchenij, rabotayushchaya na So60, i pole gamma-luchej v rizo; Instalacion de irradiacion con cobalto-60 y campo de irradiacion gamma en el centro de Riso

    Energy Technology Data Exchange (ETDEWEB)

    Brynjolfsson, A; Holm, N W [Danish Atomic Energy Commission, Establishment Riso (Denmark)

    1960-07-15

    The paper describes both the Co{sup 60} irradiation facility and the gamma field at the Agricultural Department of the Research Establishment, Riso. The Co{sup 60} irradiation facility contains 1,800 curies of Co{sup 60.} Details of the construction are given together with the safety precautions which have been included in the design. Dosimetry has been carried out by four different methods: 1. Ionisation chambers, 2. Calorimetry, 3. Fricke dosimeter, 4. Photographic films. A general outline is given of the gamma field, including details of source position. The dose rate is approximately 100 r./hr. at a distance of 1 m. An area of radius 15 m is used for the growing of plants under irradiation. A brief indication is given of the class of products which have been irradiated in the two facilities. (author) [French] Le memoire decrit l'appareil d'irradiation au cobalt-60 et le champ sous irradiation gamma du Departement de l'agriculture de l'Organisme de recherche de Riso. L'appareil d'irradiation au cobalt-60 contient une source de 1 800 curies. Des details sont donnes sur la construction ainsi que sur les dispositifs de protection compris dans le plan. Quatre methodes differentes ont ete utilisees pour la dosimetrie: 1. Chambres d'ionisation 2. Calorimetrie 3. Dosimetrie de Fricke 4. Pellicules photographique s On donne un apercu general du champ gamma, ainsi que des details sur la position de la source. L'intensite de dose est de 100 R/h environ a une distance de 1 m. Une zone d'un rayon de 15 m est utilisee pour la croissance des plantes soumises a l'irradiation. Des indications sommaires sont donnees sur la categorie des produits qui ont ete soumis a l'irradiation dans les deux installations. (author) [Spanish] Los autores describen la instalacion de irradiacion con cobalto-60 y el campo de irradiacion gamma del Departamento de Agronomia del Instituto de Investigaciones de Riso. El dispositivo de irradiacion consiste en una fuente de cobalto-60 de 1 800 curies

  13. Etude par Spectrométrie de masse de la décomposition thermique sous vide de kérogènes appartenant à deux lignées évolutives distinctes Mass Spectrometry Investigation of the Vaccum Thermal Decomposition of Kerogens from Two Distinct Evolutive Lines

    Directory of Open Access Journals (Sweden)

    Souron C.

    2006-11-01

    Full Text Available Le but de cette étude est la connaissance qualitative et quantitative des composés dégagés lors de la décomposition thermique sous vide de quelques échantillons de kérogènes appartenant à deux lignées différentes. La principale technique utilisée est la spectrométrie de masse, appuyée sur des études préliminaires par thermogravi métrie et analyse élémentaire. Une adaptation particulière de l'appareillage et une mise au point de la méthode d'étalonnage permettent de doser les quatre composés minéraux les plus abondants et de donner une représentation des composés organiques. Cette étude montre que les composés formés au cours du chauffage comprennent, pour tous les kérogènes étudiés, des composés oxygénés et soufrés (CO, H2O, SH2, SOJ libérés principalement dans l'intervalle de température 200-400° C, et des composés hydrocarbonés, plus abondants, dans l'intervalle 300-500° C. On commente dans cet article l'origine supposée de ces composés; la formation de S02 au cours de la pyrolyse est particulièrement mal connue. On remarque que le rapport H2O/C02 peut être un critère de distinction des deux lignées de kérogènes étudiés. La distinction observée sur les produits hydrocarbonés nécessitera des recherches complémentaires pour être utilisée avec plus de sûreté. The aim of this investigation is to obtain a qualitative and quantitative understanding of the compounds given off during the vacuum thermal decomposition of several kerogen samples from two different lines. The main technique used is mass spectrometry, based on prior investigations by thermogravimetry and element onalysis. The equipment was specially adapted and a calibration method was developed for titrating the four most abundant minerai compounds and for representing the organic compounds. This investigation shows that the compounds formed during heating include, for oil the kerogens examined, oxygen-and sulfur

  14. Carcinogenesis by Fast Neutrons Relative to X-Rays in Mice; Carcinogenese chez les Souris sous l'Effet des Neutrons Rapides et des Rayons X; Sravnitel'naya chastota vozniknoveniya rakovykh opukholej u myshej pri obluchenii bystrymi nejtronami i rentgenovskimi luchami; Accion Carcinogenica Comparada de los Neutrones Rapidos y de los Rayos X en el Raton

    Energy Technology Data Exchange (ETDEWEB)

    Cole, L. J.; Nowell, P. C. [Division of Biological and Medical Sciences, U.S. Naval Radiological Defense Laboratory, San Francisco, CA (United States); Department of Pathology, School of Medicine, University of Pennsylvania, Philadelphia, PA (United States)

    1964-05-15

    ). Parmi les souris du Groupe I, sacrifiees 12 a 16 mois apres l'exposition, 75% presentaient des hepatomes; ce taux atteignait 92% chez les souris du Groupe II. Par contre, des tumeurs du foie se sont produites chez 14% des souris exposees seulement aux neutrons (Groupe V) et chez 2,4% des souris exposees a une dose unique (500 rad) de rayons X de 250 kVcrete. On a observe des neoplasmes du rein chez pres de 100% des souris du Groupe IV, alors que ces lesions ont ete peu frequentes chez les souris temoins. Les auteurs etudient Inverted-Exclamation-Mark ' induction de ces neoplasmes sous l'effet de l'exposition aux neutrons et leur developpement sous l'action des agent employes pour stimuler la proliferation. En ce qui concerne l'induction de neoplasmes du rein chez les souris, les donnees indiquent un coefficient de puissance d'environ 2 pour les neutrons de fission par rapport aux rayons X de 250 kV-crete. Pour ce qui est de l'apparition de lymphomes dans cette lignee, leur frequence a ete moins importante chez les souris exposees aux neutrons (11%) que chez les sujets exposes aux rayons X (29%). (author) [Spanish] Los autores sometieron ratones jovenes adultos de la variedad LAF a una exposicion subletal unica a neutrones de fision, tratandolos de la siguiente forma: Grupo I: 195 a 199 rad, seguida de una sola inyeccion subcutanea de CCl{sub 4}, un mes despues de la exposicion; Grupo II: inyeccion de CCl{sub 4} aplicada un dia antes de la irradiacion neutronica (280 y 329 rad); Grupo III: inyeccion de CCl{sub 4} sin irradiacion; Gmpo IV: nefrectomfa unilateral un dia antes de la irradiacion (320 y 328 rad); Grupo V: irradiacion neutronica exclusivamente (200 y 320 rad). Al sacrificar los sujetos entre 12 y 16 meses a contar de la irradiacion, se encontraron hepatomas en el 75% de los ratones del Grupo I y en el 92% de los del Grupo II. En cambio, los tumores hepaticos aparecieron en el 14% de los ratones que solo fueron irradiados (Grupo V) y en el 2,4% de los expuestos

  15. The Measurement of Reactivity In Multiregion Subcritical Systems by the Pulsed Neutron Technique; Mesure de la Reactivite dans les Systemes Sous-Critiques a Plusieurs Regions par la Methode des Neutrons Pulses; Izmerenie reaktivnosti v mnogozonnykh podkriticheskikh sistemakh metodom impul'snykh nejtronov; Mediciones de la Reactividad en Sistemas Subcriticos de Varias Regiones Mediante la Tecnica de los Neutrones Pulsados

    Energy Technology Data Exchange (ETDEWEB)

    Sherwin, J.; Leng, J. H. [United Kingdom Atomic Energy Authority, Windscale Works, Cumberland (United Kingdom)

    1965-10-15

    The prompt decay of a thermalized burst of neutrons in a multiregion subcritical system is examined using a two-group diffusion theory. It is shown that a relationship can be established between the prompt decay constant of the fundamental mode and the effective multiplication factor of the system in terms of two parameters, defined, for the purposes of this paper, as the reactor response coefficient and the prompt decay correction and which depend to a large extent on the spatial flux patterns within the system. For the uniform bare system, the response coefficient can be identified with the mean neutron lifetime in the system; for a multiregion system it represents a compound of the lifetimes in each region weighted by perturbation type integrals. The second parameter, the decay correction, can have no physical meaning in that it arises from an attempt to relate the two scales of reactivity involved; that is the scale using the prompt decay constant and the scale derived using the effective multiplication factor. The properties of these parameters are examined here with reference to an enriched uranium graphitemoderated reactor consisting of uniform core and reflector and it is shown that the two parameters are not uniquely defined by the reactivity of the system but depend on the method chosen to make the system subcritical. Two sets of measurements are treated by the theory. In one, the Windscale Advanced Gas-Cooled Reactor was shut down by a uniform poison. In the other the reactivity of a core in the zero-energy reactor HERO was varied by altering the loaded radius. The neutron pulse measurements are all shown to be in good agreement with more conventional methods of reactivity determination. Some discussion of the experimental techniques and the difficulties encountered in the graphite-moderated systems is presented. (author) [French] Les auteurs etudient la decroissance des neutrons instantanes d'une bouffee thermalisee de neutrons dans un systeme sous

  16. Research with a Natural-Uranium Light-Water Subcritical Assembly; Recherches au Moyen d'un Ensemble Sous-Critique a Uranium Naturel et a Eau Ordinaire; Issledovaniya na podkriticheskoj sborke,rabotayushchej na prirodnom urane i obychnoj vode; Investigaciones con un Conjunto Subcritico de Uranio Natural y Agua Ligera

    Energy Technology Data Exchange (ETDEWEB)

    Koskinen, H. [Institute of Technical Physics, Otaniemi (Finland)

    1964-02-15

    systematic study of non-uniform lattices. In the future, enriched elements will be included in the assembly. Then systematic study of mixed lattices becomes possible, and also research with other non-uniformities will be easier because of the higher flux. Some discussion of this future programme is included in this paper. (author) [French] L'auteur relate les recherches effectuees avec un ensemble uranium naturel-eau ordinaire et enumere certains des sujets qui feront l'objet d'un prochain programme. La plus grande partie de la documentation est nouvelle. Certaines donnees ont encore un caractere provisoire, car les experiences et l'analyse des resultats se poursuivent. . Les travaux sont axes sur deux objectifs principaux: 1. Etude experimentale de la validite des methodes de calcul que l'on se propose d'utiliser, notamment en cas de geometries speciales (repartitions non uniformes du combustible, configurations de s'ous- ensembles, limites de forme particuliere, etc.). Les etudes theoriques conduisent souvent ici a certaines difficultes de convergence. Il faut donc les comparer avec les repartitions du flux mesurees. 2. Etude des proprietes particulieres des reseaux uranium naturel-eau ordinaire et notamment de la validite des modeles de ralentissement a plusieurs groupes pour des structures de coeur uniformes et non uniformes. On pense qu'un ensemble comportant une seule source de fission spontanee convient particulierement pour les recherches de ce genre, bien que la statistique ne porte que sur un petit nombre d'observations. Cela est du a deux faits: 1. On peut considerer que le spectre de la source primaire est identique a celui de la fission induite, si bien qu'il n'y a pas d'oscillations transitoires d'energie, comme dans le cas d'une source ponctuelle de neutrons rapides. 2. L'intensite de la source primaire en chaque point de l'espace est proportionnelle a la section efficace de fission du combustible lorsqu'on considere egalement cette derniere comme une fonction

  17. The Main Technological Characteristics of Apparatus for Industrial Radiochemical Processes, in Particular Ethylene Polymerization; Caracteristique techniques fondamentals des appareils pour l'application industrielle de reactions chimiques sous rayonnement (notamment la polymerisation de l'ethylene ); Osnovnye tekhnologicheskie kharakteristiki apparatov dlya provedeniya radiatsionno-khimi-cheskikh protsessov (v chastnosti, dlya polimerizatsii ehtilena) v promyshlennom masshtabe; Principales caracteristicas tecnologicas de los aparatos para la aplicacion industrial de reacciones radioquimicas

    Energy Technology Data Exchange (ETDEWEB)

    Syrkus, N P; Breger, A K; Weinstein, B I [Karpov Physicochemical Institute, Moscow, USSR (Russian Federation)

    1960-07-15

    The paper gives a general review of some of the main technological features of apparatus, for instance spherical apparatus, for industrial radiochemical processes. A method is proposed for estimating the effectiveness of apparatus of any given construction by comparing it with the output of an infinitely large apparatus having the same radiation source. An account is given of the technological features of an apparatus for radio-polymerizing ethylene at 200 atmospheres and 25{sup o}C{sup 1} with a rodshaped gamma-radiation source (Co{sup 60}) of variable activity. This apparatus can be designed to suit the mean dose rate which the power efficiency of the apparatus allows. It is shown that the yield, Q, of the apparatus is, other things being equal, a constant ration of the power, W{sub 0}, of the gamma-radiation of the apparatus. In the apparatus reviewed, Q {approx} W{sub 0}{sup 0,5}. (author) [French] Le memoire contient un expose general des caracteristiques techniques essentielles des appareils, par exemple d'un appareil du type spherique, pour l'application industrielle de reactions chimiques sous rayonnement. Le memoire propose une methode pour evaluer l'efficacite d'appareils de tous types en comparant la productivite de chaque modele avec celle d'un appareil infiniment grand, alimente par une source de rayonnement identique. Le memoire indique le calcul des caracteristiques techniques de l'appareil destine a la polymerisation sous rayonnement de l'ethylene (pression : 200 atmospheres, temperature: 25{sup o}C{sup 2} avec une source allongee de rayonnement gamma Co{sup 60} pour diverses activites. Un appareil de ce type peut etre calcule selon les valeurs moyennes de l'intensite des doses, determinees selon la valeur du coefficient d'efficacite totale energetique de l'appareil. On constate que la productivite (Q) de l'appareil, toutes choses egales d'ailleurs, est puissance de l'intensite (W{sub 0}) du rayonnement gamma de l'appareil. Pour l'appareil considere

  18. Physical Properties of P.V.C. Attenuated Network Copolymers Produced by Ionizing Radiation; Proprietes physiques des copolymeres obtenus sous l'action de rayonnements ionisants et dont le reseau est attenue par l'effet du chlorure de polyvinyle; Fizicheskie svojstva polivinilkhloridnykh obednennykh tsepej sopolimerov, poluchennykh v rezul'tate vozdejstviya ioniziruyushchej radiatsii; Propiedades fisicas de los copolimeros de redes atenuadas por cloruro de polivinilo obtenidos por irradiacion

    Energy Technology Data Exchange (ETDEWEB)

    Pinner, S H [Tube Investments Research Laboratories, Hinxton Hall, Cambridge (United Kingdom)

    1960-07-15

    The cross-linking of polyvinyl chloride with ionizing radiation poses special problems. Due to rather unfavourable cross-linking and dislinking parameters for this polymer, the radiation doses necessary for high cross-link densities are uneconomicall y large and discolouration and dehydrohalogenatio n are simultaneously produced. These difficulties have been overcome by the incorporation into the P. V. C., prior to irradiation, of diallyl and triallyl esters. Heavily cross-linked products are thereby obtained with relatively low doses of ionizing radiation. Examination of the physical properties of the products suggests that these are not simply graft copolymers, which term normally implies the presence of long branch chains, but are polymer attenuated allyl networks. In these materials, the desirable properties of the parent polymer and of the allyl network are combined. The tensile strength, modulus and elongation of the attenuated network copolymers are presented and discussed as a function of temperature and of the concentration and functionality of the allyl ester. Reference is also made to the swelling and chemical resistance of the products. (author) [French] La reticulation du chlorure de polyvinyle sous l'action des rayonnements ionisants pose des problemes particuliers. Les parametres de reticulation et de degradation etant plutot defavorables pour ce polymere, les doses d'irradiation necessaires a l'obtention de fortes densites de pontage sont trop elevees pour donner des resultats economiquement interessants; elles provoquent simultanement la decoloration et la deshalogenhydratation. Il a ete possible de surmonter ces difficultes par introduction d'esters diallyliques et triallyliques dans le chlorure de polyvinyle, avant irradiation. Ce procede permet d'obtenir au moyen de doses d'irradiation relativement faibles des produits fortement reticules. L'etude des proprietes physiques de ces produits montre qu'il s'agit non pas de simples copolymeres greffes

  19. « Le nez dans le micro ». Répercussions du travail sous commande vocale dans les entrepôts de la grande distribution alimentaire “Up front and close”. The impact of voice guidance systems in large food distribution warehouses “Estar pegado al micrófono”. Repercusiones del trabajo de activación por voz en los almacenes de la distribución alimentaria masiva

    Directory of Open Access Journals (Sweden)

    David Gaborieau

    2012-12-01

    Full Text Available Dans les entrepôts de la grande distribution alimentaire, l’introduction d’un nouvel outil de travail, le guidage par commande vocale, a considérablement modifié le travail des préparateurs de commande. Auparavant caractérisée par l’absence d’enchaînement et la possibilité de prendre de l’avance, l’activité de préparation a évolué vers une temporalité restrictive comparable à celle d’un ouvrier sur chaîne. Sous guidage vocal, « le nez dans le micro », le savoir-faire des préparateurs est réduit à un engagement physique. L’usage du corps constitue alors une ressource en tant mode d’appropriation du sens au travail, mais également un rempart lorsque des pathologies font apparaître les limites de l’intensification.Order picker operations in large food distribution warehouses have been considerably changed by a introduction of a new tool – voice guidance systems. Where the work used to be characterized by a lack of fixed sequencing and the impossibility for operatives of getting ahead of schedule, preparation activities have evolved towards more restrictive temporalities comparable to production line workers’ experience. With “up front and close” vocal guidance, order pickers’ skill is limited to their physical engagement, now considered a resource (i.e. a mode for appropriating the meaning of work but also a bulwark against the pathologies that arise as the general intensification drive reaches its limits.En los almacenes de la distribución alimentaria a gran escala, la introducción de una nueva herramienta de trabajo, el guiado activado por voz, ha transformado considerablemente el trabajo de los preparadores de pedidos. La actividad de preparación, antes caracterizada por la ausencia de secuenciación y por la posibilidad que el trabajador tenía de ganar tiempo, ha evolucionado hacia una temporalidad restrictiva comparable a la de un obrero en una cadena. Con el guiado activado por voz, al

  20. L'impact du piratage sur l'achat et le téléchargement légal. Une comparaison de quatre filières culturelles

    OpenAIRE

    Irène Bastard; Marc Bourreau; François Moreau

    2014-01-01

    Using a survey on cultural habits and consumption behavior of 2,000 individuals, we study the determinants of physical purchases and pay-downloads in four cultural industries: books, recorded music, movies, and video games. We show that the impact of piracy on legal purchases differs among these industries: it is negative for recorded music, but positive for video games. This impact also differs among individuals, when we distinguish occasional pirates from intensive ones. Our results suggest...