Tri-critical behavior in rupture induced by disorder

We discover a qualitatively new behavior for systems where the load transfer has limiting stress amplification as in real fiber composites. We find that the disorder is a relevant field leading to tri--criticality, separating a first-order regime where rupture occurs without significant precursors from a second-order regime where the macroscopic elastic coefficient exhibit power law behavior. Our results are based on analytical analysis of fiber bundle models and numerical simulations of a two-dimensional tensorial spring-block system in which stick-slip motion and fracture compete.Comment: Revtex, 10 pages, 4 figures available upon reques

Rupture Pressure Prediction for Composite High Pressure Tanks Using Acoustic Emission

The French Aerospace company AEROSPATIALE manufactures high pressure tanks for helium gas storage. Because these tanks are critical elements for rockets and satellites, a new approach has been developed to have a better knowledge of the structure reliability. Although numerical tools such as finite elements codes are used for the design of such structures and. quality rules are imposed to insure that the tanks manufactured are in accordance to the definition, it is conceivable that even a successful proof test could actually damage the composite and lead to a residual SF less than 2

Scale relativity and fractal space-time: theory and applications

In the first part of this contribution, we review the development of the theory of scale relativity and its geometric framework constructed in terms of a fractal and nondifferentiable continuous space-time. This theory leads (i) to a generalization of possible physically relevant fractal laws, written as partial differential equation acting in the space of scales, and (ii) to a new geometric foundation of quantum mechanics and gauge field theories and their possible generalisations. In the second part, we discuss some examples of application of the theory to various sciences, in particular in cases when the theoretical predictions have been validated by new or updated observational and experimental data. This includes predictions in physics and cosmology (value of the QCD coupling and of the cosmological constant), to astrophysics and gravitational structure formation (distances of extrasolar planets to their stars, of Kuiper belt objects, value of solar and solar-like star cycles), to sciences of life (log-periodic law for species punctuated evolution, human development and society evolution), to Earth sciences (log-periodic deceleration of the rate of California earthquakes and of Sichuan earthquake replicas, critical law for the arctic sea ice extent) and tentative applications to system biology.Comment: 63 pages, 14 figures. In : First International Conference on the Evolution and Development of the Universe,8th - 9th October 2008, Paris, Franc

Rocky Planetesimals as the Origin of Metals in DZ Stars

{Abridged}. An analysis of the calcium and hydrogen abundances, Galactic positions and kinematics of 146 DZ stars from the Sloan Digital Sky Survey demonstrates that interaction with the interstellar medium cannot account for their externally polluted atmospheres. The calcium-to-hydrogen ratios for the 37 DZA stars are dominated by super-solar values, as are the lower limits for the remaining 109 DZ stars. All together their metal-contaminated convective envelopes contain 10^{20+-2} g of calcium, commensurate with the masses of calcium inferred for large asteroids. It is probable that these stars are contaminated by circumstellar matter; the rocky remains of terrestrial planetary systems. In this picture, two predictions emerge: 1) at least 3.5% of all main sequence A- and F-type stars build terrestrial planets; and 2) the DZA stars are externally polluted by both metals and hydrogen, and hence constrain the frequency and mass of water-rich, extrasolar planetesimals.Comment: Accepted to MNRA

A Study of the Day - Night Effect for the Super - Kamiokande Detector: I. Time Averaged Solar Neutrino Survival Probability

This is the first of two articles aimed at providing comprehensive predictions for the day-night (D-N) effect for the Super-Kamiokande detector in the case of the MSW \nu_e \to \numt transition solution of the solar neutrino problem. The one-year averaged probability of survival of the solar \nue crossing the Earth mantle, the core, the inner 2/3 of the core, and the (core + mantle) is calculated with high precision (better than 1%) using the elliptical orbit approximation (EOA) to describe the Earth motion around the Sun. Results for the survival probability in the indicated cases are obtained for a large set of values of the MSW transition parameters $\Delta m^2$ and $sin^22\theta_{V}$ from the ``conservative'' regions of the MSW solution, derived by taking into account possible relatively large uncertainties in the values of the $^{8}$B and $^{7}$Be neutrino fluxes. Our results show that the one-year averaged D-N asymmetry in the $\nu_e$ survival probability for neutrinos crossing the Earth core can be, in the case of $sin^22 \theta_{V} \leq 0.13$, larger than the asymmetry in the probability for (only mantle crossing + core crossing) neutrinos by a factor of up to six. The enhancement is larger in the case of neutrinos crossing the inner 2/3 of the core. This indicates that the Super-Kamiokande experiment might be able to test the $sin^22\theta_{V} \leq 0.01$ region of the MSW solution of the solar neutrino problem by performing selective D-N asymmetry measurements.Comment: LaTeX2e - 18 Text Pages + 21 figures = 39 Pages. - Figures in PS + text file sk1b14.tex requires two auxiliary files (included

Dragon-kings: mechanisms, statistical methods and empirical evidence

This introductory article presents the special Discussion and Debate volume "From black swans to dragon-kings, is there life beyond power laws?" published in Eur. Phys. J. Special Topics in May 2012. We summarize and put in perspective the contributions into three main themes: (i) mechanisms for dragon-kings, (ii) detection of dragon-kings and statistical tests and (iii) empirical evidence in a large variety of natural and social systems. Overall, we are pleased to witness significant advances both in the introduction and clarification of underlying mechanisms and in the development of novel efficient tests that demonstrate clear evidence for the presence of dragon-kings in many systems. However, this positive view should be balanced by the fact that this remains a very delicate and difficult field, if only due to the scarcity of data as well as the extraordinary important implications with respect to hazard assessment, risk control and predictability.Comment: 20 page

A Study of the Day - Night Effect for the Super-Kamiokande Detector: II. Electron Spectrum Deformations and Day - Night Asymmetries

Using the results of a high precision calculation of the solar neutrino survival probability for Earth crossing neutrinos in the case of MSW $\nu_e \to \nu_{\mu(\tau)}$ transition solution of the solar neutrino problem, performed in an earlier study, we derive predictions for the one-year averaged day-night (D-N) asymmetry in the deformations of the $e^-$ - spectrum to be measured with the Super - Kamiokande detector, and for the D-N asymmetry in the energy- integrated one year signal in this detector. The asymmetries are calculated for solar $\nu_e$ crossing the Earth mantle only, the core and the (mantle + core) for a large representative set of values of the MSW transition parameters $\Delta m^2$ and $\sin^2 2\theta_v$ from the ``conservative'' MSW solution region obtained by taking into account possible uncertainties in the values of the $^8$B and $^7$Be neutrino fluxes. The effect of the uncertainties in the value of the bulk matter density and in the chemical composition of the core, on the D-N asymmetry predictions is discussed. It is shown, in particular, that for $\sin^2 2\theta_v \leq 0.013$ the one year average D-N asymmetry for neutrinos crossing the Earth core can be larger than the asymmetry for (only mantle crossing + core crossing) neutrinos by a factor of up to six. Iso - (D-N) asymmetry contours in the $\Delta m^2 - \sin^2 2\theta_v$ plane for the Super - Kamiokande detector are derived in the region \sin^2 2\theta_v \gsim 10^{-4} for only mantle crossing, core crossing and (only mantle crossing + core crossing) neutrinos. Our results indicate that the Super - Kamiokande experiment might be able to test the $\sin^2 2\theta_v \le 0.01$ region of the MSW solution of the solar neutrino problem by performing selective D-N asymmetry measurements.Comment: LaTeX, 18 pages, 3 Tables, 16 Figures in 7 postscript file

Mantle Pb paradoxes : the sulfide solution

Author Posting. © Springer, 2006. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Contributions to Mineralogy and Petrology 152 (2006): 295-308, doi:10.1007/s00410-006-0108-1.There is growing evidence that the budget of Pb in mantle peridotites is largely contained in sulfide, and that Pb partitions strongly into sulfide relative to silicate melt. In addition, there is evidence to suggest that diffusion rates of Pb in sulfide (solid or melt) are very fast. Given the possibility that sulfide melt ‘wets’ sub-solidus mantle silicates, and has very low viscosity, the implications for Pb behavior during mantle melting are profound. There is only sparse experimental data relating to Pb partitioning between sulfide and silicate, and no data on Pb diffusion rates in sulfides. A full understanding of Pb behavior in sulfide may hold the key to several long-standing and important Pb paradoxes and enigmas. The classical Pb isotope paradox arises from the fact that all known mantle reservoirs lie to the right of the Geochron, with no consensus as to the identity of the “balancing” reservoir. We propose that long-term segregation of sulfide (containing Pb) to the core may resolve this paradox. Another Pb paradox arises from the fact that the Ce/Pb ratio of both OIB and MORB is greater than bulk earth, and constant at a value of 25. The constancy of this “canonical ratio” implies similar partition coefficients for Ce and Pb during magmatic processes (Hofmann et al. 1986), whereas most experimental studies show that Pb is more incompatible in silicates than Ce. Retention of Pb in residual mantle sulfide during melting has the potential to bring the bulk partitioning of Ce into equality with Pb if the sulfide melt/silicate melt partition coefficient for Pb has a value of ~ 14. Modeling shows that the Ce/Pb (or Nd/Pb) of such melts will still accurately reflect that of the source, thus enforcing the paradox that OIB and MORB mantles have markedly higher Ce/Pb (and Nd/Pb) than the bulk silicate earth. This implies large deficiencies of Pb in the mantle sources for these basalts. Sulfide may play other important roles during magmagenesis: 1). advective/diffusive sulfide networks may form potent metasomatic agents (in both introducing and obliterating Pb isotopic heterogeneities in the mantle); 2). silicate melt networks may easily exchange Pb with ambient mantle sulfides (by diffusion or assimilation), thus ‘sampling’ Pb in isotopically heterogeneous mantle domains differently from the silicate-controlled isotope tracer systems (Sr, Nd, Hf), with an apparent ‘de-coupling’ of these systems.Our intemperance should not be blamed on the support we gratefully acknowledge from NSF: EAR- 0125917 to SRH and OCE-0118198 to GAG

Benchmark numerical simulations of rarefied non-reacting gas flows using an open-source DSMC code

Validation and verification represent an important element in the development of a computational code. The aim is establish both confidence in the algorithm and its suitability for the intended purpose. In this paper, a direct simulation Monte Carlo solver, called dsmcFoam, is carefully investigated for its ability to solve low and high speed non-reacting gas flows in simple and complex geometries. The test cases are: flow over sharp and truncated flat plates, the Mars Pathfinder probe, a micro-channel with heated internal steps, and a simple micro-channel. For all the cases investigated, dsmcFoam demonstrates very good agreement with experimental and numerical data available in the literature

Melting and differentiation of early-formed asteroids: The perspective from high precision oxygen isotope studies

A number of distinct methodologies are available for determining the oxygen isotope composition of minerals and rocks, these include laser-assisted fluorination, secondary ion mass spectrometry (SIMS)and UV laser ablation. In this review we focus on laser-assisted fluorination, which currently achieves the highest levels of precision available for oxygen isotope analysis. In particular, we examine how results using this method have furthered our understanding of early-formed differentiated meteorites. Due to its rapid reaction times and low blank levels, laser-assisted fluorination has now largely superseded the conventional externally-heated Ni “bomb” technique for bulk analysis. Unlike UV laser ablation and SIMS analysis, laser-assisted fluorination is not capable of focused spot analysis. While laser fluorination is now a mature technology, further analytical improvements are possible via refinements to the construction of sample chambers, clean-up lines and the use of ultra-high resolution mass spectrometers. High-precision oxygen isotope analysis has proved to be a particularly powerful technique for investigating the formation and evolution of early-formed differentiated asteroids and has provided unique insights into the interrelationships between various groups of achondrites. A clear example of this is seenin samples that lie close to the terrestrial fractionation line (TFL). Based on the data from conventional oxygen isotope analysis, it was suggested that the main-group pallasites, the howardite eucrite diogenite suite (HEDs) and mesosiderites could all be derived from a single common parent body. However,high precision analysis demonstrates that main-group pallasites have a Δ17O composition that is fully resolvable from that of the HEDs and mesosiderites, indicating the involvement of at least two parent bodies. The range of Δ17O values exhibited by an achondrite group provides a useful means of assessing the extent to which their parent body underwent melting and isotopic homogenization. Oxygen isotope analysis can also highlight relationships between ungrouped achondrites and the more well-populated groups. A clear example of this is the proposed link between the evolved GRA 06128/9 meteorites and the brachinites. The evidence from oxygen isotopes, in conjunction with that from other techniques, indicates that we have samples from approximately 110 asteroidal parent bodies (∼60 irons, ∼35 achondrites and stony-iron, and ∼15 chondrites) in our global meteorite collection. However, compared to the likely size of the original protoplanetary asteroid population, this is an extremely low value. In addition, almost all of the differentiated samples (achondrites, stony-iron and irons) are derived from parent bodies that were highly disrupted early in their evolution. High-precision oxygen isotope analysis of achondrites provides some important insights into the origin of mass-independent variation in the early Solar System. In particular, the evidence from various primitive achondrite groups indicates that both the slope 1 (Y&R) and CCAM lines are of primordial significance. Δ17O differences between water ice and silicate-rich solids were probably the initial source of the slope 1 anomaly. These phases most likely acquired their isotopic composition as a result of UV photo-dissociation of CO that took place either in the early solar nebula or precursor giant molecular cloud. Such small-scale isotopic heterogeneities were propagated into larger-sized bodies, such as asteroids and planets, as a result of early Solar System processes, including dehydration, aqueous alteration,melting and collisional interactions