Low cycle fatigue in turbines

Behavior of certain components at low-cycle fatigue is a parameter related to the conditions of use of turbines, to the technology of engine production and to the precision of its regulation. The laboratory takes this into account using data from sophisticated tests and rigorous analyses. The production plan includes careful examination of possible causes of premature rupture. This parameter has motivated the metallurgy industry to develop new materials and new technology

Analysis of reproductive performances during the formation of a synthetic rabbit strain

[EN] In 1995, a synthetic rabbit strain ('2666') was formed at INRA for commercial meat purposesby crossing the INRA '2066' strain and the 'V' strain from the Polytechnical University of Valencia (Spain).The development of some reproductive traits and body weight at palpation of the '2666' does was studiedfrom the F1 (first generation cross) to the F4 generation in comparison with the 'V' does. This developmentwas quantified in terms of Dickerson's crossbreeding parameters. The base strains did not differ significantlyfor any of the studied traits, either overall or in their direct and maternal genetic value. F1 does exhibitedsignificant individual heterosis for body weight (5.5% of the parental average), pregnancy rate (13.3%),total born (18.3%), born alive (24.4%) and weaned (21.0%) per litter born. Concerning body weight, asignificant crossbred superiority over the 'V' line was retained in the F2 but not thereafter. The rate ofpregnancy showed no crossbred advantage from the F2 on. Concerning litter size traits, the benefit ofcrossbreeding was maintained until the F4, but at a lower magnitude than in the F1. Body weight andpregnancy rate exhibited maternal heterosis, while litter size did not. Direct epistatic losses were significantfor body weight, tended towards significance for pregnancy rate, but did not affect litter size. Overall, thecomparison between the synthetic strain and the founders was favourable to the synthetics.Brun, J.; Baselga, M. (2005). Analysis of reproductive performances during the formation of a synthetic rabbit strain. World Rabbit Science. 13. doi:10.4995/wrs.2005.514SWORD1

Auxetic two-dimensional lattice with Poisson's Ratio arbitrarily close to -1

In this paper we propose a new lattice structure having macroscopic Poisson's ratio arbitrarily close to the stability limit -1. We tested experimentally the effective Poisson's ratio of the micro-structured medium; the uniaxial test has been performed on a thermoplastic lattice produced with a 3d printing technology. A theoretical analysis of the effective properties has been performed and the expression of the macroscopic constitutive properties is given in full analytical form as a function of the constitutive properties of the elements of the lattice and on the geometry of the microstructure. The analysis has been performed on three micro-geometry leading to an isotropic behaviour for the cases of three-fold and six-fold symmetry and to a cubic behaviour for the case of four-fold symmetry.Comment: 26 pages, 12 figures (26 subfigures

Platonic crystal with low-frequency locally resonant snail structures. Wave trapping, transmission amplification and shielding

We propose a new type of platonic crystal. The proposed microstructured plate includes snail resonators with low-frequency resonant vibrations. The particular dynamic effect of the resonators are highlighted by a comparative analysis of dispersion properties of homo- geneous and perforated plates. Analytical and numerical estimates of classes of standing waves are given and the analysis on a macrocell shows the possibility to obtain localization, wave trapping and edge waves. Applications include transmission amplification within two plates separated by a small ligament. Finally we proposed a design procedure to suppress low frequency flexural vibration in an elongated plate implementing a by-pass system re- routing waves within the mechanical system.Comment: 11 figures (20 files

Is the solar convection zone in strict thermal wind balance?

Context: The solar rotation profile is conical rather than cylindrical as one could expect from classical rotating fluid dynamics (e.g. Taylor-Proudman theorem). Thermal coupling to the tachocline, baroclinic effects and latitudinal transport of heat have been advocated to explain this peculiar state of rotation. Aims: To test the validity of thermal wind balance in the solar convection zone using helioseismic inversions for both the angular velocity and fluctuations in entropy and temperature. Methods: Entropy and temperature fluctuations obtained from 3-D hydrodynamical numerical simulations of the solar convection zone are compared with solar profiles obtained from helioseismic inversions. Results: The temperature and entropy fluctuations in 3-D numerical simulations have smaller amplitude in the bulk of the solar convection zone than those found from seismic inversions. Seismic inversion find variations of temperature from about 1 K at the surface up to 100 K at the base of the convection zone while in 3-D simulations they are of order 10 K throughout the convection zone up to 0.96 $R_{\odot}$. In 3-D simulations, baroclinic effects are found to be important to tilt the isocontours of $\Omega$ away from a cylindrical profile in most of the convection zone helped by Reynolds and viscous stresses at some locations. By contrast the baroclinic effect inverted by helioseismology are much larger than what is required to yield the observed angular velocity profile. Conclusion: The solar convection does not appear to be in strict thermal wind balance, Reynolds stresses must play a dominant role in setting not only the equatorial acceleration but also the observed conical angular velocity profile.Comment: 8 pages, 6 figures (low resolution), Accepted by Astronomy and Astrophysics - Affiliation: (1) AIM, CEA/DSM-CNRS-Univ. Paris Diderot, IRFU/SAp, France & (2) LUTH, Observatoire de Paris, CNRS-Univ. Paris Diderot, France ; (3) Tata Institute of Fundamental Research, India; (4) Centre for Basic Sciences, University of Mumbai, Indi

Simulations of closed timelike curves

Proposed models of closed timelike curves (CTCs) have been shown to enable powerful information-processing protocols. We examine the simulation of models of CTCs both by other models of CTCs and by physical systems without access to CTCs. We prove that the recently proposed transition probability CTCs (T-CTCs) are physically equivalent to postselection CTCs (P-CTCs), in the sense that one model can simulate the other with reasonable overhead. As a consequence, their information-processing capabilities are equivalent. We also describe a method for quantum computers to simulate Deutschian CTCs (but with a reasonable overhead only in some cases). In cases for which the overhead is reasonable, it might be possible to perform the simulation in a table-top experiment. This approach has the benefit of resolving some ambiguities associated with the equivalent circuit model of Ralph et al. Furthermore, we provide an explicit form for the state of the CTC system such that it is a maximum-entropy state, as prescribed by Deutsch.Comment: 15 pages, 1 figure, accepted for publication in Foundations of Physic

An algorithm for quantifying dependence in multivariate data sets

We describe an algorithm to quantify dependence in a multivariate data set. The algorithm is able to identify any linear and non-linear dependence in the data set by performing a hypothesis test for two variables being independent. As a result we obtain a reliable measure of dependence. In high energy physics understanding dependencies is especially important in multidimensional maximum likelihood analyses. We therefore describe the problem of a multidimensional maximum likelihood analysis applied on a multivariate data set with variables that are dependent on each other. We review common procedures used in high energy physics and show that general dependence is not the same as linear correlation and discuss their limitations in practical application. Finally we present the tool CAT, which is able to perform all reviewed methods in a fully automatic mode and creates an analysis report document with numeric results and visual review.Comment: 4 pages, 3 figure

Extra Shared Entanglement Reduces Memory Demand in Quantum Convolutional Coding

We show how extra entanglement shared between sender and receiver reduces the memory requirements for a general entanglement-assisted quantum convolutional code. We construct quantum convolutional codes with good error-correcting properties by exploiting the error-correcting properties of an arbitrary basic set of Pauli generators. The main benefit of this particular construction is that there is no need to increase the frame size of the code when extra shared entanglement is available. Then there is no need to increase the memory requirements or circuit complexity of the code because the frame size of the code is directly related to these two code properties. Another benefit, similar to results of previous work in entanglement-assisted convolutional coding, is that we can import an arbitrary classical quaternary code for use as an entanglement-assisted quantum convolutional code. The rate and error-correcting properties of the imported classical code translate to the quantum code. We provide an example that illustrates how to import a classical quaternary code for use as an entanglement-assisted quantum convolutional code. We finally show how to "piggyback" classical information to make use of the extra shared entanglement in the code.Comment: 7 pages, 1 figure, accepted for publication in Physical Review