Sample records for damage evolution law

  1. Glen's Law++: Transition to a Rate-Weakening Flow Law As a New Framework for Damage Evolution

    NASA Astrophysics Data System (ADS)

    Borstad, C. P.; Morlighem, M.; Khazendar, A.; Scheuchl, B.; Larour, E. Y.; Rignot, E. J.

    2014-12-01

    Continuum damage mechanics is gaining increasing acceptance as a framework for modeling flow enhancement caused by fractures in glaciers and ice shelves. To date, the temporal evolution of viscous damage has been handled using a transport equation with some kind of source term for damage. A number of empirical formulations for such a source term have been adopted, though no clear physical foundation exists for treating damage using flux terms. Furthermore, it remains to be demonstrated that the parameters of such a source term can be determined from observations. Here, we introduce a new framework for damage evolution that does not require specifying a damage source term and that results in a more intuitive physical interpretation of the coupled evolution of stress and damage. By postulating an explicit rate-weakening flow law above a threshold stress, damage can be calculated analytically from the results of a stress balance computation. A transport equation is still applied to advect damage, but the evolution of damage is explicitly linked to the evolving stress balance. This new damage formulation requires only two new parameters, both of which have clear physical interpretations and can be inferred from observations. Using the Ice Sheet System Model (ISSM), we determine values for both parameters by inverting for damage for the remnant Larsen B ice shelf using a time series of InSAR velocity data covering the years 2000-2010. The inferred patterns of damage and strain rate, in both space and time, are used to quantify the rate-weakening constitutive parameters using nonlinear regression. The resulting damage evolution framework is then applied in perturbation experiments to determine the conditions and timescales under which the remnant Larsen B ice shelf may collapse. We conclude by discussing advantages of this approach to damage evolution and applications to problems in iceberg calving, ice shelf stability, and buttressing at the grounding line.

  2. MICROMECHANICS-BASED MODELING OF DAMAGE EVOLUTION IN VISCOELASTIC COMPOSITES

    Microsoft Academic Search

    R. S. KUMAR; R. TALREJA

    Damage in composite laminates affects their overall viscoelastic response. Previous research has been focused on developing constitutive equations for these materials considering a fixed state of damage. A complete description, however, requires suitable damage evolution laws. This paper is focused on studying damage evolution in viscoelastic laminates using a computational micromechanics approach. We use cohesive finite elements to study nucleation

  3. Evolution and the Law

    ERIC Educational Resources Information Center

    Mayer, William V.

    1973-01-01

    Some court cases and legislative bills have been filed in states to legalize the use of the creationist view (of life forms on earth) in biology textbooks superseding the organic theory of evolution. The law has not yet accepted the religious viewpoint. (PS)

  4. Ductile Damage Evolution and Strain Path Dependency

    SciTech Connect

    Tasan, C. C. [Netherlands Institute for Metals Research (NIMR), PO Box 5008, 2600GA, Delft (Netherlands); Eindhoven University of Technology, Department of Mechanical Engineering, PO Box 513, 5600MB, Eindhoven (Netherlands); Hoefnagels, J. M. P.; Peerlings, R. H. J.; Geers, M. G. D. [Eindhoven University of Technology, Department of Mechanical Engineering, PO Box 513, 5600MB, Eindhoven (Netherlands); ten Horn, C. H. L. J.; Vegter, H. [Corus Research Development and Technology, PO Box 10000, 1970 CA IJmuiden (Netherlands)

    2007-04-07

    Forming limit diagrams are commonly used in sheet metal industry to define the safe forming regions. These diagrams are built to define the necking strains of sheet metals. However, with the rise in the popularity of advance high strength steels, ductile fracture through damage evolution has also emerged as an important parameter in the determination of limit strains. In this work, damage evolution in two different steels used in the automotive industry is examined to observe the relationship between damage evolution and the strain path that is followed during the forming operation.

  5. Damage evolution in filled elastomers

    NASA Astrophysics Data System (ADS)

    Ha, K.; Park, S.; Schapery, R. A.

    1993-06-01

    This report summarizes theoretical and experimental research on distributed damage growth and its effect on stress-strain behavior and on the strain distribution around macrocracks in particle-filled rubber. Two Appendices provide details on the constitutive model, experimental determination of deformation and damage in specimens under axial straining and confining pressure, and experimental measurement of strain fields in biaxially-stressed specimens with cracks.

  6. Evolution of the Second Law of Thermodynamics

    ERIC Educational Resources Information Center

    Raman, V. V.

    1970-01-01

    Presents the history surrounding the evolution of the second law of thermodynamics. Discusses Sadi Carnot's contributions, but also refers to those by Clapeyron, Thomson, Joule, Clausius, and Boltzman among others. (RR)

  7. Radiation damage evolution in ceramics

    SciTech Connect

    Devanathan, Ramaswami

    2009-09-15

    A review is presented of recent results on radiation damage production, defect accumulation and dynamic annealing in a number of ceramics, such as silicon carbide, zircon and zirconia. Under energetic particle irradiation, ceramics can undergo amorphization by the accumulation of point defects and defect clusters (silicon carbide) or direct impact amorphization (zircon). Ceramics that resist radiation-induced amorphization have mechanisms to dissipate the primary knock-on atom energy, such as replacement collision sequences that leave the lattice undisturbed and low-energy cation site exchange. The presence of engineered mobile defects, such as structural vacancies in stabilized zirconia, can dynamically anneal radiation damage. Thus, defect engineering is a promising strategy to design radiation tolerance for applications such as nuclear waste disposal.

  8. Stochastic damage evolution in textile laminates

    NASA Technical Reports Server (NTRS)

    Dzenis, Yuris A.; Bogdanovich, Alexander E.; Pastore, Christopher M.

    1993-01-01

    A probabilistic model utilizing random material characteristics to predict damage evolution in textile laminates is presented. Model is based on a division of each ply into two sublaminas consisting of cells. The probability of cell failure is calculated using stochastic function theory and maximal strain failure criterion. Three modes of failure, i.e. fiber breakage, matrix failure in transverse direction, as well as matrix or interface shear cracking, are taken into account. Computed failure probabilities are utilized in reducing cell stiffness based on the mesovolume concept. A numerical algorithm is developed predicting the damage evolution and deformation history of textile laminates. Effect of scatter of fiber orientation on cell properties is discussed. Weave influence on damage accumulation is illustrated with the help of an example of a Kevlar/epoxy laminate.

  9. DAMAGE EVOLUTION IN DYNAMIC DEFORMATION OF

    Microsoft Academic Search

    M. A. MEYERS; V. F. NESTERENKO

    1 Abstract—Damage evolution was investigated in silicon carbide by subjecting it to dynamic deformation in (a) a compression Hopkinson-Kolsky bar (compressive stresses of 5 GPa), and (b) high-velocity impact under confinement (compressive stresses of 19-32 GPa) by a cylindrical (rod) tungsten alloy projectile. Considerable evidence of plastic deformation, as dislocations and stacking faults, was found in the frac- tured specimens.

  10. Spall behavior and damage evolution in tantalum

    SciTech Connect

    Zurek, A.K.; Thissell, W.R.; Tonks, D.L.

    1995-09-01

    The authors conducted a number of plate impact experiments using an 80-mm launcher to study dynamic void initiation, linkup, and spall in tantalum. The tests ranged in shock pressure so that the transition from void initiation, incipient spall, and full spall could be studied. Wave profiles were measured using a velocity interferometry system (VISAR), and targets were recovered using soft recovery techniques. The authors utilized scanning electron microscopy, metallographic cross-sections, and plateau etching to obtain quantitative information concerning damage evolution in tantalum under spall conditions. The data (wave profiles and micrographs) are analyzed in terms of a new theory and model of dynamic damage cluster growth. They have developed a model of ductile damage based on void coalescence of initially nucleated voids, that leads to clusters of voids. At low loading strain rates, the biggest cluster has time to grow much more rapidly than smaller clusters to break the sample. At high loading strain rates, large clusters cannot grow any faster than smaller clusters so the sample breaks when enough clusters grow independently to form a fracture surface by random accumulation.

  11. Fracture and damage evolution of fluorinated polymers

    SciTech Connect

    Brown, E. N. (Eric N.); Rae, P. (Philip); Orler, E. B. (E. Bruce); Thissell, W. R. (W. Richards); Dattelbaum, D. M. (Dana M.)

    2004-01-01

    Fluoropolymers are often semi-crystalline in nature, with their linear chains forming complicated phases near room temperature and ambient pressure. The most widely used fluorocarbon polymer for engineering applications is polytetrafluoroethylene (PTFE), due to its extremely low coefficient of friction, outstanding resistance to corrosion, and excellent electrical properties. The phase structure of PTFE is complex with four well-characterized crystalline phases (three observed at atmospheric pressure) and substantial molecular motion well below the melting point. The first-order transition at 19 C between phases II and IV is an unraveling in the helical conformation. Further rotational disordering and untwisting of the helices occurs above 30 C giving way to phase I. The mechanical behavior, including fracture and damage evolution, of PTFE depends on the chain and segment motions dictated by crystalline phase microstructure. The presence of three unique phases at ambient pressure near room temperature implies that failure during standard operating conditions may be strongly dependent on the phase. This paper presents a preliminary study of fracture and damage evolution in PTFE with the effects of temperature-induced phase on fracture mechanisms. The quasi-static fracture of PTFE in the atmospheric pressure regime, over a range of temperatures, was found to be strongly phase dependent: phase II exhibits brittle-fracture, phase IV displays ductile-fracture with crazing and some stable crack growth, and plastic flow dominates phase 1. The bulk failure properties are correlated to failure mechanisms through fractography of the fracture surfaces (optical microscopy and scanning electron microscopy (SEM)).

  12. Conservation laws and normal forms of evolution equations

    E-print Network

    Roman O. Popovych; Artur Sergyeyev

    2010-03-08

    We study local conservation laws for evolution equations in two independent variables. In particular, we present normal forms for the equations admitting one or two low-order conservation laws. Examples include Harry Dym equation, Korteweg-de-Vries-type equations, and Schwarzian KdV equation. It is also shown that for linear evolution equations all their conservation laws are (modulo trivial conserved vectors) at most quadratic in the dependent variable and its derivatives.

  13. Investigation of shear damage considering the evolution of anisotropy

    NASA Astrophysics Data System (ADS)

    Kweon, S.

    2013-12-01

    The damage that occurs in shear deformations in view of anisotropy evolution is investigated. It is widely believed in the mechanics research community that damage (or porosity) does not evolve (increase) in shear deformations since the hydrostatic stress in shear is zero. This paper proves that the above statement can be false in large deformations of simple shear. The simulation using the proposed anisotropic ductile fracture model (macro-scale) in this study indicates that hydrostatic stress becomes nonzero and (thus) porosity evolves (increases or decreases) in the simple shear deformation of anisotropic (orthotropic) materials. The simple shear simulation using a crystal plasticity based damage model (meso-scale) shows the same physics as manifested in the above macro-scale model that porosity evolves due to the grain-to-grain interaction, i.e., due to the evolution of anisotropy. Through a series of simple shear simulations, this study investigates the effect of the evolution of anisotropy, i.e., the rotation of the orthotropic axes onto the damage (porosity) evolution. The effect of the evolutions of void orientation and void shape onto the damage (porosity) evolution is investigated as well. It is found out that the interaction among porosity, the matrix anisotropy and void orientation/shape plays a crucial role in the ductile damage of porous materials.

  14. Evolution of damage and plasticity in

    NASA Astrophysics Data System (ADS)

    Majumdar, B. S.; Newaz, G. M.; Ellis, J. R.

    1993-07-01

    The inelastic deformation mechanisms were evaluated for a model titanium-based, fiber-reinforced composite: a beta titanium alloy (Ti-15V-3Al-3Cr-3Sn) reinforced with SiC (SCS-6) fibers. The primary emphasis of this article is to illustrate the sequence in which damage and plasticity evolved for this system. The mechanical responses and the results of detailed microstructural evaluations for the [0]8, [90]8, and [±45]2s, laminates are provided. It is shown that the char- acteristics of the reaction zone around the fiber play a very important role in the way damage and plasticity evolve, particularly in the microyield regime of deformation, and must be included in any realistic constitutive model. Fiber-matrix debonding was a major damage mode for the off-axis systems. The tension test results are also compared with the predictions of a few con- stitutive models.

  15. Local conservation laws of second-order evolution equations

    E-print Network

    Roman O. Popovych; Anatoly M. Samoilenko

    2008-08-06

    Generalizing results by Bryant and Griffiths [Duke Math. J., 1995, V.78, 531-676], we completely describe local conservation laws of second-order (1+1)-dimensional evolution equations up to contact equivalence. The possible dimensions of spaces of conservation laws prove to be 0, 1, 2 and infinity. The canonical forms of equations with respect to contact equivalence are found for all nonzero dimensions of spaces of conservation laws.

  16. Conservation laws for self-adjoint ?rst order evolution equations

    E-print Network

    Igor Leite Freire

    2011-04-26

    In this work we consider the problem on group classification and conservation laws of the general first order evolution equations. We obtain the subclasses of these general equations which are quasi-self-adjoint and self-adjoint. By using the recent Ibragimov's Theorem on conservation laws, we establish the conservation laws of the equations admiting self-adjoint equations. We illustrate our results applying them to the inviscid Burgers' equation. In particular an infinite number of new symmetries of these equations are found and their corresponding conservation laws are established.

  17. A differential evolution tuned optimal guidance law

    Microsoft Academic Search

    Raghunathan Thangavelu; S. Pradeep

    2007-01-01

    The optimal guidance law (OGL) is based on the assumptions of linear kinematical model of missile guidance and unconstrained control in a linear quadratic regulator formulation. These are strong assumptions that are rarely satisfied in practice; the kinematics of the missile-target engagement is highly nonlinear, and infinite lateral acceleration -which is the control -is a physical impossibility. As a consequence,

  18. Experimental and numerical characterization of damage evolution in steels

    Microsoft Academic Search

    Diego J. Celentano; Jean-Louis Chaboche

    2007-01-01

    This paper presents an experimental and numerical characterization of ductile damage evolution in steels subjected to large plastic deformations. To this end, a set of tensile tests combining load–unload tensile cycles is firstly carried out in order to evaluate the deterioration exhibited by the Young’s modulus for increasing levels of plastic deformation. This task allows, in turn, to derive the

  19. The evolution of law in biopreparedness.

    PubMed

    Hodge, James G

    2012-03-01

    The decade following the terrorist attacks on September 11, 2001, and ensuing anthrax exposures that same fall has seen significant legal reforms designed to improve biopreparedness nationally. Over the past 10 years, a transformative series of legal changes have effectively (1) rebuilt components of federal, state, and local governments to improve response efforts; (2) created an entire new legal classification known as "public health emergencies"; and (3) overhauled existing legal norms defining the roles and responsibilities of public and private actors in emergency response efforts. The back story as to how law plays an essential role in facilitating biopreparedness, however, is pocked with controversies and conflicts between law- and policymakers, public health officials, emergency managers, civil libertarians, scholars, and others. Significant legal challenges for the next decade remain. Issues related to interjurisdictional coordination; duplicative legal declarations of emergency, disaster, and public health emergency; real-time legal decision making; and liability protections for emergency responders and entities remain unresolved. This article explores the evolving tale underlying the rise and prominence of law as a pivotal tool in national biopreparedness and response efforts in the interests of preventing excess morbidity and mortality during public health emergencies. PMID:22455677

  20. The Necessity of Evolution: Law and Logic in Darwin's Explanation

    ERIC Educational Resources Information Center

    Gough, Noel P.

    1978-01-01

    Recognition of the logic of Darwin's explanation has significance for understanding evolution and for appreciation of the extent to which Darwin's concept of evolutionary mechanism accords with modern evolutionary thought. Darwin's explanation exemplifies the concept of a scientific law and can help learners to understand the nature of scientific…

  1. Sequential law in multiaxial fatigue, a new damage indicator

    Microsoft Academic Search

    G. Mesmacque; S. Garcia; A. Amrouche; C. Rubio-Gonzalez

    2005-01-01

    One of the largest difficulties in fatigue damage is to find a representative ‘Damage indicator’ which can be easily connected with the Wöhler curve taken as known data of the material. The most used model is the Miner's rule but this does not take into account the loading history, so for the same loading level the experimental results are higher

  2. The constructal law of design and evolution in nature

    PubMed Central

    Bejan, Adrian; Lorente, Sylvie

    2010-01-01

    Constructal theory is the view that (i) the generation of images of design (pattern, rhythm) in nature is a phenomenon of physics and (ii) this phenomenon is covered by a principle (the constructal law): ‘for a finite-size flow system to persist in time (to live) it must evolve such that it provides greater and greater access to the currents that flow through it’. This law is about the necessity of design to occur, and about the time direction of the phenomenon: the tape of the design evolution ‘movie’ runs such that existing configurations are replaced by globally easier flowing configurations. The constructal law has two useful sides: the prediction of natural phenomena and the strategic engineering of novel architectures, based on the constructal law, i.e. not by mimicking nature. We show that the emergence of scaling laws in inanimate (geophysical) flow systems is the same phenomenon as the emergence of allometric laws in animate (biological) flow systems. Examples are lung design, animal locomotion, vegetation, river basins, turbulent flow structure, self-lubrication and natural multi-scale porous media. This article outlines the place of the constructal law as a self-standing law in physics, which covers all the ad hoc (and contradictory) statements of optimality such as minimum entropy generation, maximum entropy generation, minimum flow resistance, maximum flow resistance, minimum time, minimum weight, uniform maximum stresses and characteristic organ sizes. Nature is configured to flow and move as a conglomerate of ‘engine and brake’ designs. PMID:20368252

  3. Damage evolution in dynamic deformation of silicon carbide

    Microsoft Academic Search

    C. J. Shih; M. A. Meyers; V. F. Nesterenko; S. J. Chen

    2000-01-01

    Damage evolution was investigated in silicon carbide by subjecting it to dynamic deformation in (a) a compression Hopkinson–Kolsky bar (compressive stresses of 5 GPa), and (b) high-velocity impact under confinement (compressive stresses of 19–32 GPa) by a cylindrical (rod) tungsten alloy projectile. Considerable evidence of plastic deformation, as dislocations and stacking faults, was found in the fractured specimens. A polytype

  4. Stochastic damage evolution modeling in laminates. Ph.D. Thesis

    SciTech Connect

    Dzenis, Y.A.

    1994-01-01

    A stochastic mesomechanics model has been developed for damage accumulation analysis in advanced laminated composites. The model is based on a theory of excursions of random process beyond the limiting bounds. Stochastic strains in the laminate subjected to random Gaussian in-plane loading are calculated using lamination theory and random functions theory. Probabilistic variation of stiffness and strength characteristics of plies are used in the analysis. A stochastic version of maximum strain failure criterion is applied for damage probability calculation. A mesovolume concept is utilized in modeling stiffness degradation. The model is verified experimentally based on the available data. Capabilities of the model are illustrated by predictions of damage accumulation and failure in a Kevlar/epoxy (0/ +/- 30/90){sub s} laminate under quasistationary, long-term stationary, and cyclic loading. Effects of loading rate, deviation, stationary level and cyclic amplitude on damage evolution are discussed. High-cycle fatigue behavior of laminate is calculated utilizing the observed stages in failure accumulation under the cyclic loading. Percolation type analysis of damage morphology is performed for the inhomogeneous anisotropic media. The model and computer codes developed can be incorporated into structural analysis software and used in design of laminated structures.

  5. Law of genome evolution direction: Coding information quantity grows

    NASA Astrophysics Data System (ADS)

    Luo, Liao-Fu

    2009-06-01

    The problem of the directionality of genome evolution is studied. Based on the analysis of C-value paradox and the evolution of genome size, we propose that the function-coding information quantity of a genome always grows in the course of evolution through sequence duplication, expansion of code, and gene transfer from outside. The function-coding information quantity of a genome consists of two parts, p-coding information quantity that encodes functional protein and n-coding information quantity that encodes other functional elements. The evidences on the law of the evolutionary directionality are indicated. The needs of function are the motive force for the expansion of coding information quantity, and the information quantity expansion is the way to make functional innovation and extension for a species. Therefore, the increase of coding information quantity of a genome is a measure of the acquired new function, and it determines the directionality of genome evolution.

  6. Cohesive Laws and Progressive Damage Analysis of Composite Bonded Joints, a Combined Numerical/Experimental Approach

    NASA Technical Reports Server (NTRS)

    Girolamo, Donato; Davila, Carlos G.; Leone, Frank A.; Lin, Shih-Yung

    2015-01-01

    The results of an experimental/numerical campaign aimed to develop progressive damage analysis (PDA) tools for predicting the strength of a composite bonded joint under tensile loads are presented. The PDA is based on continuum damage mechanics (CDM) to account for intralaminar damage, and cohesive laws to account for interlaminar and adhesive damage. The adhesive response is characterized using standard fracture specimens and digital image correlation (DIC). The displacement fields measured by DIC are used to calculate the J-integrals, from which the associated cohesive laws of the structural adhesive can be derived. A finite element model of a sandwich conventional splice joint (CSJ) under tensile loads was developed. The simulations, in agreement with experimental tests, indicate that the model is capable of predicting the interactions of damage modes that lead to the failure of the joint.

  7. A multiscale model for predicting damage evolution in heterogeneous viscoelastic media 

    E-print Network

    Searcy, Chad Randall

    2004-11-15

    the effects of local scale damage. Damage, in the form discrete cracks, is allowed to grow according to a micromechanically-based viscoelastic traction-displacement law. Finite element formulations have been developed for both the global and local scale...

  8. Chromosome damage evolution after low and high LET irradiation

    NASA Astrophysics Data System (ADS)

    Andreev, Sergey; Eidelman, Yuri

    Ionizing radiation induces DNA and chromatin lesions which are converted to chromosome lesions detected in the first post-irradiation mitosis by classic cytogenetic techniques as chromosomal aberrations (CAs). These techniques allow to monitor also delayed aberrations observed after many cell generations post-irradiation - the manifestation of chromosomal instability phenotype (CIN). The problem discussed is how to predict time evolution from initial to delayed DNA/chromosome damage. To address this question, in the present work a mechanistic model of CIN is elaborated which integrates pathways of (*) DNA damage induction and its conversion to chromosome lesions (aberrations), (**) lesion transmission and generation through cell cycles. Delayed aberrations in subsequent cycles are formed in the model owing to two pathways, DNA damage generation de novo as well as CA transmission from previous cycles. DNA damage generation rate is assumed to consist of bystander and non-bystander components. Bystander signals impact all cells roughly equally, whereas non-bystander DSB generation rate differs for the descendants of unirradiated and irradiated cells. Monte Carlo simulation of processes underlying CIN allows to predict the time evolution of initial radiation-induced damage - kinetics curve for delayed unstable aberrations (dicentrics) together with dose response and RBE as a function of time after high vs low LET irradiation. The experimental data for radiation-induced CIN in TK6 lymphoblastoid cells and human lymphocytes irradiated with low (gamma) and high (Fe, C) LET radiation are analyzed on the basis of the proposed model. One of the conclusions is that without bystander signaling, just taking into account the initial DNA damage and non-bystander DSB generation, it is impossible to describe the available experimental data for high-LET-induced CIN. The exact contribution of bystander effects for high vs low LET remains unknown, but the relative contribution may be assessed at large times after initial acute irradiation. RBE for delayed aberrations depends on LET, time and cell line, which probably reflects a genetic background for bystander component. The proposed modeling approach creates a basis for integration of complex network of bystander/inflammatory signaling in systems-level platform for quantification of radiation induced CIN.

  9. Study of nanoscale damage evolution using embedded atom method potentials

    NASA Astrophysics Data System (ADS)

    Potirniche, Gabriel; Horstemeyer, Mark; Gullet, Phillip

    2004-03-01

    Damage evolution at nanoscale has been studied using embedded atom method (EAM) potentials based on molecular dynamics principles. The simulations were performed using WARP, a parallel computing atomistic stress simulator based on Lennard-Jones (LJ) potentials for Aluminum. By varying the number of atoms from a few hundred to a few hundred thousands, we analyzed void nucleation, growth and coalescence at increasing material length scale. Rectangular specimens with and without voids were subjected to uniaxial tension up to a total strain of 50rates. Uniaxial stress-strain curves, void-volume fraction evolution and stress triaxiality were monitored. The results indicated that nucleation process is highly dependent on the material length scale, while the void growth and void coalescence mechanisms were almost indifferent to the increasing length scale. Material length scale mostly affects dislocation nucleation mechanisms that lead to void formation. Strain rate also significantly influences the stress-strain response during plastic deformation at various length scales.

  10. The effect of interfacial properties on damage evolution in model composites

    Microsoft Academic Search

    Thomas J. Mackin; Teresa L. Halverson; Nancy R. Sottos

    2005-01-01

    This study explores the effect of interfacial properties on damage evolution and damage mechanisms in model glass fiber reinforced epoxy matrix composites. The composite properties were varied by changing the inter- facial bond between the fiber and the matrix. Double- edge-notched specimens were tested in tension and evaluated using thermoelastic stress analysis (TSA) to observe damage initiation and evolution, and

  11. Scaling Laws for Convection with Temperature-dependent Viscosity and Grain-damage

    E-print Network

    Foley, Bradford J

    2014-01-01

    Numerical experiments of convection with grain-damage are used to develop scaling laws for convective heat flow, mantle velocity, and plate velocity across the stagnant lid and plate-tectonic regimes. Three main cases are presented in order of increasing complexity: a simple case wherein viscosity is only dependent on grainsize, a case where viscosity depends on temperature and grainsize, and finally a case where viscosity is temperature and grainsize sensitive, and the grain-growth (or healing) is also temperature sensitive. In all cases, convection with grain-damage scales differently than Newtonian convection due to the effects of grain-damage. For the fully realistic case, numerical results show stagnant lid convection, fully mobilized convection that resembles the temperature-independent viscosity case, and partially mobile or transitional convection, depending on damage to healing ratio, Rayleigh number, and the activation energies for viscosity and healing. Applying our scaling laws for the fully reali...

  12. The production and evolution of scaling laws via galaxy merging

    NASA Astrophysics Data System (ADS)

    Covington, Matthew D.

    2008-12-01

    Galaxy mergers are a major force in the formation of galaxies. We study a large suite of hydrodynamical galaxy merger simulations in order to better understand how mergers could lead to the development and evolution of galaxy scaling laws. We begin by constructing a physically-motivated analytical model that predicts the properties of the remnants of galaxy mergers. The free parameters in this model are calibrated using the simulation set. Once developed, the merger model is applied to two Semi-Analytic Models of galaxy formation and used to study the production and evolution of elliptical galaxy scaling laws via merging. We demonstrate that major mergers of disk galaxies are capable of producing the observed scaling relations. The tilt of the fundamental plane and the rotation of the size-mass relation from that of disks, are the result of a gas gradient in the progenitor galaxies. We also demonstrate that galaxy mergers are capable of reproducing the observed high-redshift Tully-Fisher law outliers along with the tight S 0.5 -stellar mass relation. Furthermore, we show using the simulations that S 0.5 tracks the total enclosed mass including the contribution from dark matter.

  13. Defect and damage evolution quantification in dynamically-deformed metals using orientation-imaging microscopy

    SciTech Connect

    Gray, George T., III [Los Alamos National Laboratory; Livescu, Veronica [Los Alamos National Laboratory; Cerreta, Ellen K [Los Alamos National Laboratory

    2010-03-18

    Orientation-imaging microscopy offers unique capabilities to quantify the defects and damage evolution occurring in metals following dynamic and shock loading. Examples of the quantification of the types of deformation twins activated, volume fraction of twinning, and damage evolution as a function of shock loading in Ta are presented. Electron back-scatter diffraction (EBSD) examination of the damage evolution in sweeping-detonation-wave shock loading to study spallation in Cu is also presented.

  14. Einstein's evolution equations as a system of balance laws

    SciTech Connect

    Bona, C.; Masso, J. (Departament de Fiiaasica, Universitat de les Illes Balears, E-07071 Palma de Mallorca, Spain (ES))

    1989-08-15

    The evolution system in the space plus time (3+1) decomposition of Einstein's field equations is explicitly written as a system of balance laws. This is achieved by demanding that the time coordinate be harmonic (harmonic synchronization) and the space coordinate lines be normal to the constant-time hypersurfaces. No symmetry nor special form of the metric has been assumed, so that the equations may be used as a part of a three-dimensional numerical code for general relativity. The particular case of spherical symmetry is also considered and a numerical test of this case is provided by using a nonstandard form of the Schwarzschild line element.

  15. On-site inspections of pavement damages evolution using GPR

    NASA Astrophysics Data System (ADS)

    Tosti, Fabio; D'Amico, Fabrizio; Calvi, Alessandro; Benedetto, Andrea

    2014-05-01

    Ground-penetrating radar (GPR) is being increasingly used for pavements maintenance due to the wide range of applications spanning from physical to geometrical inspections, thereby allowing for a reliable diagnosis of the main causes of road structural damages. In this work, an off-ground GPR system was used to investigate a large-scale rural road network. Two sets of surveys were carried out in different time periods, with the main goals to i) localize the most critical sections; ii) monitor the evolution of previous damages and localize newborn deep faults, although not revealed at the pavement surface level; iii) analyze the causes of both evolution and emergence of faults by considering environmental and human factors. A 1-GHz GPR air-launched antenna was linked to an instrumented van for collecting data at traffic speed. Other support techniques (e.g. GPS data logger, odometer, HD video camera) were used for cross-checking,. Such centre frequency of investigation along with a 25-ns time window allow for a signal penetration of 900 mm, consistent with the deepest layer interfaces. The bottom of the array was 400 mm over the surface, with a minimum distance of 1200 mm from the van body. Scan length of maximum 10 km were provided for avoiding heavy computational loads. The rural road network was located in the District of Rieti, 100 km north from Rome, Italy, and mostly develops in a hilly and mountainous landscape. In most of the investigated roads, the carriageway consists in two lanes of 3.75 meters wide and two shoulders of 0.50 meters wide. A typical road section includes a HMA layer (65 mm average thickness), a base layer (100 mm average thickness), and a subbase layer (300 mm average thickness), as described by pavement design charts. The first set of surveys was carried out in two days at the beginning of spring in moderately dry conditions. Overall, 320-km-long inspections were performed in both travel directions, thereby showing a productivity of approximately 160 km/day at 40 km/h speed, on the average. After processing and first-checking, GPR profiles were divided into homogeneous sections according to the combination of different parameters (e.g. route analyzed, long distance conditions of regularity/irregularity in layers arrangement). In such context, a high consistency between surface damages, mismatches from the GPR scans, and boundary environmental conditions was demonstrated. In addition, deep mismatches were detected even for early-stage or unrevealed faults. The second set of surveys was carried out in autumn in high humidity conditions, due to recent rainfalls. 160 km of relevant routes from the same road network were investigated. Results showed a high consistency with those collected during the first-stage of surveys. Minor changes were found in those sections with low traffic loads (e.g. farther away from the biggest town of Rieti), whereas major mismatches were detected in wetlands (e.g. close to rivers), work zones, and nearby those sections already deeply damaged in the past. This work benefited from networking activities carried out within the EU funded COST Action TU1208 'Civil Engineering Applications of Ground Penetrating Radar'.

  16. [Case of law-evading herbs poisoning that induced shock and myocardial damage].

    PubMed

    Nakamura, Yoshihiko; Nakano, Minoru; Nakamura, Mitsunobu; Miyazaki, Dai; Okamori, Satoshi; Akuzawa, Hisashi; Yuasa, Masahiro

    2014-12-01

    Law-evading herbs may induce poisoning symptoms, especially when they contain synthetic cannabinoids. However, their detailed pharmacological effects have not yet been clarified. Some reports have previously described symptoms of poisoning, but only a few reports have so far described shock and myocardial damage (MD). We experienced a case of shock and MD in a patient who had smoked law-evading herbs. A 61-year-old male presented at an emergency department 8 hours after smoking law-evading herbs (Rush Trip, High Men Monster) with chest pain. A vasopressor agent was administered to treat shock and antiarrhythmic drugs were administered due to ventricular arrhythmia. The contents of the law-evading herbs were unknown, so an in-hospital follow-up was conducted to treat the patient's symptoms. The follow-up blood test showed an increased level of cardiac enzymes, which thereafter demonstrated a spontaneous remission. The systemic conditions tended to improve and the patient was discharged from the hospital on the 5th hospital day. The contents of the law-evading herbs in question were thereafter,analyzed, and synthetic cannabinoids (JWH-210, JWH-081 and JWH-122) as well as caffeine were detected. The cause for the poisoning symptoms were suspected to be the presence of synthetic cannabinoids and caffeine. Such law-evading herbs may contain synthetic cannabinoids and caffeine which both may induce shock and MD. PMID:25771668

  17. The Morning after the Year of Darwin. Book review. The Laws of Evolution and the Derived

    E-print Network

    Badyaev, Alex

    Pr:374 The Morning after the Year of Darwin. Book review. The Laws of Evolution Ł69.95. ­ As much of the western scientific community reflects on the Year of Darwin festivities revisions of its history, The Laws of Evolution gives us pause. It reminds us that evolutionary

  18. Damage Evolution On Mechanical Parts Under Cyclic Loading

    Microsoft Academic Search

    P. Lestriez; F. Bogard; J. L. Shan; Y. Q. Guo

    2007-01-01

    This paper presents a fatigue damage model, based on the continuum damage mechanics and general thermodynamic theory, proposed by Lemaitre and Chaboche, for rolling bearings under very numerous loading cycles. A flow surface of fatigue using the Sines criterion is adopted. The coupling between the hardening plasticity and damage effects is considered in the constitutive equations. An explicit algorithm of

  19. Damage Evolution On Mechanical Parts Under Cyclic Loading

    NASA Astrophysics Data System (ADS)

    Lestriez, P.; Bogard, F.; Shan, J. L.; Guo, Y. Q.

    2007-05-01

    This paper presents a fatigue damage model, based on the continuum damage mechanics and general thermodynamic theory, proposed by Lemaitre and Chaboche, for rolling bearings under very numerous loading cycles. A flow surface of fatigue using the Sines criterion is adopted. The coupling between the hardening plasticity and damage effects is considered in the constitutive equations. An explicit algorithm of weak coupling leads to a calculation very fast. This fatigue damage model is implemented into Abaqus/Explicit using a Vumat user's subroutine. Moreover, the damage variable in function of time is transformed into a function of number of cycles. An algorithm of cycle jump, with a criterion for choosing the number increment of cycles, is proposed, which allows to largely reduce the CPU time. The present damage simulation allows to determine the lifetime of mechanical parts under cyclic loading.

  20. Collateral damage: Evolution with displacement of fracture distribution and secondary fault strands in fault

    E-print Network

    Savage, Heather M.

    Collateral damage: Evolution with displacement of fracture distribution and secondary fault strands in fault damage zones Heather M. Savage1,2 and Emily E. Brodsky1 Received 22 April 2010; revised 10 faults is governed by the same process. Based on our own field work combined with data from

  1. Use of atomic force microscopy for characterizing damage evolution during fatigue

    Microsoft Academic Search

    Laurent Cretegny

    2000-01-01

    A study of the development of surface fatigue damage in PH 13-8 Mo stainless steel and copper by atomic force microscopy (AFM) was performed. AFM observations allow highly automated, quantitative characterization of surface deformation with a resolution of 5 nm or better, which is ideal for understanding fatigue damage evolution. A secondary objective was to establish a correlation between fatigue

  2. Tensile properties and damage evolution in vascular 3D woven glass/epoxy composites

    E-print Network

    Sottos, Nancy R.

    Tensile properties and damage evolution in vascular 3D woven glass/epoxy composites Anthony M management [6,7], electrical and magnetic modulation [1], and damage detection [8­10]. In bulk polymers Microvascular a b s t r a c t Vascularization enables multifunctional composites capable of self

  3. Law, evolution and the brain: applications and open questions.

    PubMed Central

    Jones, Owen D

    2004-01-01

    This paper discusses several issues at the intersection of law and brain science. It focuses principally on ways in which an improved understanding of how evolutionary processes affect brain function and human behaviour may improve law's ability to regulate behaviour. It explores sample uses of such 'evolutionary analysis in law' and also raises questions about how that analysis might be improved in the future. Among the discussed uses are: (i) clarifying cost-benefit analyses; (ii) providing theoretical foundation and potential predictive power; (iii) assessing comparative effectiveness of legal strategies; and (iv) revealing deep patterns in legal architecture. Throughout, the paper emphasizes the extent to which effective law requires: (i) building effective behavioural models; (ii) integrating life-science perspectives with social-science perspectives; (iii) considering the effects of brain biology on behaviours that law seeks to regulate; and (iv) examining the effects of evolutionary processes on brain design. PMID:15590611

  4. Fracture in sheet metal forming: Effect of ductile damage evolution

    Microsoft Academic Search

    M. Khelifa; M. Oudjene; A. Khennane

    2007-01-01

    This work deals with the virtual simulation of the sheet metal stamping process. The main objective is to predict when and where the cracks can appear in the workpiece during the forming operation. A local approach based on the strong coupling between anisotropic elastoplasticity with mixed nonlinear work hardening (isotropic and kinematic) and an isotropic ductile damage is proposed. The

  5. Damage Evolution in Composites with a Homogenization-based Continuum

    E-print Network

    Ghosh, Somnath

    .1177/1056789508091563 #12;introduction of effective damage parameters that represent overall material degradation (Chaboche, 1981; Kachanov, 1987; Lemaitre and Chaboche, 1990; Krajicinovic, 1996; Nemat-Nasser and Hori, 1999 materials. The phenomenological CDM models (Chaboche, 1981; Ortiz, 1985; Simo and Ju, 1987; Chow and Wang

  6. Fatigue Damage Evolution in Silicon Films for Micromechanical Applications

    E-print Network

    Suo, Zhigang

    of stable crack growth by stress corrosion cracking prior to the onset of unstable crack growth in the SiO2 the importance of stress corrosion cracking phenomena (in the topical SiO2 layer on Si) as the key process topography evolution and crack growth/fracture dur- ing the cyclic actuation of polysilicon

  7. Experimental and Analytical Evaluation of Stressing-Rate State Evolution in Rate-State Friction Laws

    NASA Astrophysics Data System (ADS)

    Bhattacharya, P.; Rubin, A. M.; Bayart, E.; Savage, H. M.; Marone, C.; Beeler, N. M.

    2013-12-01

    Standard rate and state friction laws fail to explain the full range of observations from laboratory friction experiments. A new state evolution law has been proposed by Nagata et al. (2012) that adds a linear stressing-rate-dependent term to the Dieterich (aging) law, which may provide a remedy. They introduce a parameter c that controls the contribution of the stressing rate to state evolution. We show through analytical approximations that the new law can transition between the responses of the traditional Dieterich (aging) and Ruina (slip) laws in velocity step up/down experiments when the value of c is tuned properly. In particular, for c = 0 the response is pure aging while for finite, non-zero c one observes slip law like behavior for small velocity jumps but aging law like response for larger jumps. The magnitude of the velocity jump required to see this transition between aging and slip behaviour increases as c increases. In the limit of c >> 1 the response to velocity steps becomes purely slip law like. In this limit, numerical simulations show that this law loses its appealing time dependent healing property. An approach using Markov Chain Monte Carlo parameter search on data for large magnitude velocity step tests reveals that it is only possible to determine a lower bound on c using datasets that are well explained by the slip law. For a dataset with velocity steps of two orders of magnitude on simulated fault gouge we find this lower bound to be c ? 10.0. This is significantly larger than c ? 2.0 used by Nagata et al. (2012) to fit their data (mainly bare rock experiments with smaller excursions from steady state than our dataset). Similar parameter estimation exercises on slide hold slide data reveal that none of the state evolution laws considered - Dieterich, Ruina, Kato-Tullis and Nagata - match the relevant features of the data. In particular, even the aging law predicts only the correct rate of healing for long hold times but not the correct amount of healing. For c = 10.0, the Nagata law shows significant slip dependence in healing rate for long hold times which is at odds with the lab data and similar to the slip law response. If one accepts frictional healing observed in the laboratory as a ';proper' analog for fault strengthening over the interseismic period, we conclude that none of the investigated state evolution laws provides a comprehensive and correct constitutive relation.

  8. Nonlinear differential equation for fatigue damage evolution, using a micromechanical model

    Microsoft Academic Search

    Eli Altus

    2002-01-01

    A 1-D discrete (cycle by cycle) micromechanical fatigue model, which represents a material made from an ensemble of elements having statistical (Weibull) strength distribution, has been developed in previous works. In the present study, the recursive type equations have been transformed into a continuous form, leading to a nonlinear second order differential equation of damage evolution (stiffness reduction), for which

  9. Effects of grain refinement and strength on friction and damage evolution under repeated sliding contact in nanostructured metals

    E-print Network

    Suresh, Subra

    Effects of grain refinement and strength on friction and damage evolution under repeated sliding of grain sizes well below 100 nm, was studied. The evolution of friction and damage during repeated sliding with that in ultrafine-crystalline and microcrystalline materials so as to develop a broad perspective on the effects

  10. Microstructure: Property correlation. [multiaxial fatigue damage evolution in waspaloy

    NASA Technical Reports Server (NTRS)

    Jayaraman, N.

    1990-01-01

    Strain controlled torsional and biaxial (tension-torsion) low cycle fatigue behavior of Waspaloy was studied at room temperature as a function of heat treatment. Biaxial tests were conducted under proportional (when the axial and torsional strain cycles are in-phase) and non-proportional (when the axial and torsional strain cycles are 90 deg out-of-phase) cyclic conditions. The deformation behavior under these different cyclic conditions were evaluated by slip trace analysis. For this, a Schmidt-type factor was defined for multiaxial loading conditions and it was shown that when the slip deformation is predominant, non-proportional cycles are more damaging than proportional or pure axial or torsional cycles. This was attributed to the fact that under non-proportional cyclic conditions, deformation was through multiple slip as opposed single slip for other loading conditions, which gave rise to increased hardening. The total life for a given test condition was found to be independent of heat treatment. This was interpreted as being due to the differences in the cycles to initiation and propagation of cracks.

  11. The Evolution of the Exponent of Zipf's Law in Language Ontogeny

    PubMed Central

    Baixeries, Jaume; Elvevĺg, Brita; Ferrer-i-Cancho, Ramon

    2013-01-01

    It is well-known that word frequencies arrange themselves according to Zipf's law. However, little is known about the dependency of the parameters of the law and the complexity of a communication system. Many models of the evolution of language assume that the exponent of the law remains constant as the complexity of a communication systems increases. Using longitudinal studies of child language, we analysed the word rank distribution for the speech of children and adults participating in conversations. The adults typically included family members (e.g., parents) or the investigators conducting the research. Our analysis of the evolution of Zipf's law yields two main unexpected results. First, in children the exponent of the law tends to decrease over time while this tendency is weaker in adults, thus suggesting this is not a mere mirror effect of adult speech. Second, although the exponent of the law is more stable in adults, their exponents fall below 1 which is the typical value of the exponent assumed in both children and adults. Our analysis also shows a tendency of the mean length of utterances (MLU), a simple estimate of syntactic complexity, to increase as the exponent decreases. The parallel evolution of the exponent and a simple indicator of syntactic complexity (MLU) supports the hypothesis that the exponent of Zipf's law and linguistic complexity are inter-related. The assumption that Zipf's law for word ranks is a power-law with a constant exponent of one in both adults and children needs to be revised. PMID:23516390

  12. Damage detection and conductivity evolution in carbon nanofiber epoxy via electrical impedance tomography

    NASA Astrophysics Data System (ADS)

    Tallman, T. N.; Gungor, S.; Wang, K. W.; Bakis, C. E.

    2014-04-01

    Utilizing electrically conductive nanocomposites for integrated self-sensing and health monitoring is a promising area of structural health monitoring (SHM) research wherein local changes in conductivity coincide with damage. In this research we conduct proof of concept investigations using electrical impedance tomography (EIT) for damage detection by identifying conductivity changes and by imaging conductivity evolution in a carbon nanofiber (CNF) filled epoxy composite. CNF/epoxy is examined because fibrous composites can be manufactured with a CNF/epoxy matrix thereby enabling the entire matrix to become self-sensing. We also study the mechanisms of conductivity evolution in CNF/epoxy through electrical impedance spectroscopy (EIS) testing. The results of these tests indicate that thermal expansion is responsible for conductivity evolution in a CNF/epoxy composite.

  13. Numerical Simulations of Inter-laminar Damage Evolution in a Composite Wing Box

    NASA Astrophysics Data System (ADS)

    Riccio, A.; Raimondo, A.; Borrelli, R.; Mercurio, U.; Tescione, D.; Scaramuzzino, F.

    2014-06-01

    In this paper, a numerical study has been carried out on skin delamination and skin-stringer debonding growth in a composite wing-box under compressive loading conditions. The adopted numerical models use the Virtual Crack Closure Technique to simulate the inter-laminar damage evolution and the numerical analyses have been performed by means of the FEM code ABAQUS and B2000++. The obtained numerical results have been assessed and compared each other in terms of delaminated area evolution, delamination growth initiation load and strain distributions. In order to investigate the effectiveness of the adopted numerical platforms in predicting the evolution of inter-laminar damages, comparisons with experimental data, in terms of load displacement curves and strains in the debonding area, have been also introduced.

  14. The evolution of Zipf's law indicative of city development

    E-print Network

    Chen, Yanguang

    2015-01-01

    Zipf's law of city-size distributions can be expressed by three types of mathematical models: one-parameter form, two-parameter form, and three-parameter form. The one-parameter and one of the two-parameter models are familiar to urban scientists. However, the three-parameter model and another type of two-parameter model have not attracted attention. This paper is devoted to exploring the conditions and scopes of application of this Zipf models. By mathematical reasoning and empirical analysis, new discoveries are made as follows. First, if the size distribution of cities in a geographical region cannot be described with the one- or two-parameter model, maybe it can be characterized by the three-parameter model with a scaling factor and a scale-translational factor. Second, all these Zipf models can be unified by hierarchical scaling laws based on cascade structure. Third, the patterns of city-size distributions seems to evolve from three-parameter mode to two-parameter mode, and then to one-parameter mode. F...

  15. Reduction of mesh sensitivity in continuum damage mechanics

    Microsoft Academic Search

    W. A. M. Brekelmans; J. H. P. de Vree

    1995-01-01

    Summary Continuum damage theories can be applied to simulate the failure behaviour of engineering constructions. In the constitutive equations of the material a damage parameter is incorporated. A damage criterion and a damage evolution law are postulated and quantified based on experimental data. The elaboration of the mathematical formulation is performed by common finite element techniques. Without special precautions the

  16. Worldtube conservation laws for the null-timelike evolution problem

    E-print Network

    Jeffrey Winicour

    2011-05-17

    I treat the worldtube constraints which arise in the null-timelike initial-boundary value problem for the Bondi-Sachs formulation of Einstein's equations. Boundary data on a worldtube and initial data on an outgoing null hypersurface determine the exterior spacetime by integration along the outgoing null geodsics. The worldtube constraints are a set of conservation laws which impose conditions on the integration constants. I show how these constraints lead to a well-posed initial value problem governing the extrinsic curvature of the worldtube, whose components are related to the integration constants. Possible applications to gravitational waveform extraction and to the well-posedness of the null-timelike initial-boundary value problem are discussed.

  17. Fatigue-damage evolution and damage-induced reduction of critical current of a Nb3Al superconducting composite

    NASA Astrophysics Data System (ADS)

    Ochiai, S.; Sekino, F.; Sawada, T.; Ohno, H.; Hojo, M.; Tanaka, M.; Okuda, H.; Koganeya, M.; Hayashi, K.; Yamada, Y.; Ayai, N.; Watanabe, K.

    2003-09-01

    We have studied the fatigue-damage mechanism of a Nb3Al superconducting composite at room temperature, and the influences of the fatigue damages introduced at room temperature on the critical current at 4.2 K and the residual strength at room temperature. The main (largest) fatigue crack arose first in the clad copper and then extended into the inner core with an increasing number of stress cycles. The cracking of the Nb3Al filaments in the core region occurred at a late stage (around 60-90% of the fatigue life). Once the fracture of the core occurred, it extended very quickly, resulting in a quick reduction in critical current and the residual strength with increasing stress cycles. Such a behaviour was accounted for by the crack growth calculated from the S-N curves (the relation of the maximum stress to the number of stress cycles at failure) combined with the Paris law. The size and distribution of the subcracks along the specimen length, and therefore the reduction in critical current of the region apart from the main crack, were dependent on the maximum stress level. The large subcracks causing fracture of the Nb3Al filaments were formed when the maximum stress was around 300-460 MPa, resulting in large reduction in critical current, but not when the maximum stress was outside such a stress range.

  18. The relationship between microstructure and damage evolution in hot-rolled complex-phase steel sheet

    NASA Astrophysics Data System (ADS)

    Bell, Grant A. S.

    Complex-phase (CP) steels are employed in applications that require high-strength and good edge formability. These steels derive their strength from a fine-grained bainite-ferrite microstructure, and alloying to provide solid-solution and precipitation strengthening. CP steels are produced industrially through a process of controlled rolling and cooling to produce desirable microstructures. Hole-expansion tests are typically used as a measure of edge formability for applications such as stretch-flanges. It has been shown that CP microstructures are susceptible to large fluctuations in hole-expansion performance with little change in processing or resulting tensile properties. The steel's characteristics of damage evolution are critical to the hole-expansion performance. This study investigates the role of microstructure in the development of damage in CP microstructural variants. Two variant pairs of different thicknesses were produced from the leading and trailing edge of industrially produced hot-rolled sheet. Each pair consisted of a variant with poor hole-expansion performance, and a variant with good hole-expansion performance. Each variant was tested via interrupted double-notched uniaxial tension testing to induce damage. Damage evolution in each variant was quantified by X-ray micro-computed tomography (XmicroCT), and supplementary optical micrography. The damage results were correlated with microstructural characteristics. It was shown that poor hole-expansion variants failed by intergranular fracture. In these variants, void damage induced by hard martensite and retained austenite was not critical in producing failure. Purely void-damaged microstructures failed by ductile fracture, whereas cracked microstructures failed in a mixed brittle-ductile failure initiated by planar cracks. Microstructural banding of large elongated ferrite grains correlated with the existence of intergranular planar fractures.

  19. Power-law behavior in the quantum-resonant evolution of the ? -kicked accelerator

    NASA Astrophysics Data System (ADS)

    Halkyard, P. L.; Saunders, M.; Gardiner, S. A.; Challis, K. J.

    2008-12-01

    We consider the atom-optical ? -kicked accelerator when the initial momentum distribution is symmetric. We demonstrate the existence of quantum-resonant dynamics, and derive analytic expressions for the system evolution. In particular, we consider the dynamical evolution of the momentum moments and find that all even-ordered momentum moments exhibit a power-law growth. In the ultracold (zero-temperature) limit the exponent is determined by the order of the moment, whereas for a broad, thermal initial momentum distribution the exponent is reduced by 1. To demonstrate the power-law behavior explicitly we consider the evolutions of the second- and fourth-order momentum moments, and cumulants, for an initially Gaussian momentum distribution corresponding to the Maxwell-Boltzmann distribution of an ideal gas at thermal equilibrium.

  20. Power-law behavior in the quantum-resonant evolution of the delta-kicked accelerator

    E-print Network

    P. L. Halkyard; M. Saunders; S. A. Gardiner; K. J. Challis

    2008-09-25

    We consider the atom-optical delta-kicked accelerator when the initial momentum distribution is symmetric. We demonstrate the existence of quantum-resonant dynamics, and derive analytic expressions for the system evolution. In particular, we consider the dynamical evolution of the momentum moments and find that all even-ordered momentum moments exhibit a power law growth. In the ultracold (zero-temperature) limit the exponent is determined by the order of the moment, whereas for a broad, thermal initial momentum distribution the exponent is reduced by one. To demonstrate the power law behavior explicitly we consider the evolutions of the second- and fourth-order momentum moments, and cumulants, for an initially Gaussian momentum distribution corresponding to the Maxwell-Boltzmann distribution of an ideal gas at thermal equilibrium.

  1. The Influence of Grain Boundary Type upon Damage Evolution at Grain Boundary Interfaces

    SciTech Connect

    Perez-Bergquist, Alejandro G [Los Alamos National Laboratory; Brandl, Christian [Los Alamos National Laboratory; Escobedo, Juan P [Los Alamos National Laboratory; Trujillo, Carl P [Los Alamos National Laboratory; Cerreta, Ellen K [Los Alamos National Laboratory; Gray III, George T [Los Alamos National Laboratory; Germann, Timothy C [Los Alamos National Laboratory

    2012-07-09

    In a prior work, it was found that grain boundary structure strongly influences damage evolution at grain boundaries in copper samples subjected to either shock compression or incipient spall. Here, several grain boundaries with different grain boundary structures, including a {Sigma}3 (10-1) boundary, are interrogated via conventional transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) to investigate the effects of atomic-scale structural differences on grain boundary strength and mobility. Boundaries are studied both before and after shock compression at a peak shock stress of 10 GPa. Results of the TEM and HRTEM work are used in conjunction with MD modeling to propose a model for shock-induced damage evolution at grain boundary interfaces that is dependent upon coincidence.

  2. Damage Evolution and Fault reactivation during Stimulation of a Geothermal Reservoir

    NASA Astrophysics Data System (ADS)

    Abe, Steffen; Karrech, Ali; Regenauer-Lieb, Klaus; Deckert, Hagen

    2014-05-01

    In many geothermal projects the generation of additional fluid pathways, for example by injecting fluid into the geothermal well under high pressure, is necessary to achieve the required rate of fluid flow. Because in a number of geological setting pre-existing faults are the prefered target structures for geothermal wells, the interaction between the faults and fluid pressures generated during the stimulation needs to be considered as well as the influence of the faults of fluid flow. Therefore a good understanding of the interaction and feedback between permeability, porous flow and damage evolution is needed. In this study we are using numerical simulations of the coupled hydro-mechanical processes to investigate the relation between fluid injection, damage evolution and possible fault reactivation in a simplified model of a geothermal reservoir. The simulations are based on a Finite Element model including the damage evolution procedure developed by Karrech et al. 2014 [1]. The geometry, material properties and stress conditions used in the models are based on the available data from the geothermal site in Soultz-sous-Forets (France). The dominant geometrical structure in the model is a steeply dipping fault zone. Otherwise the rock is considered homogeneous. The geometry of the fault zone and its location relative to the well is simplified from Evans et al. 2005 [2]. The stress boundary conditions are taken from Cornet et al. 2007 [3]. Initial results show that the evolution of the damage, and therefore the permeability, in the model is strongly dependent on the material parameters, in particular the amount of pre-existing damage in fault zone. Under the injection pressures considered in this study a reactivation of the fault appears to be feasible only if the fault is already very weak prior to the stimulation. [1] A.Karrech, C.Schrank, R.Freij-Ayoub and K.Regenauer-Lieb, 2014, A multi-scaling approach to predict hydraulic damage of poromaterials, Int. J. Mech. Sci., v. 78, p. 1-7 [2] K.F.Evans, A.Genter and J. Sausse, 2005, Permeability creation and damage due to massive fluid injections into granite at 3.5 km at Soultz: 1. Borehole observations, J. Geophys. Res., v. 110, B04203 [3] F.H. Cornet, Th. Berard and S. Bourouis, 2007, How close to failure is a granite rock mass at a 5km depth?, Int. J. Rock. Mech. Min. Sci., v. 44, p. 47-66

  3. Damage evolution in GLARE fibre-metal laminate under repeated low-velocity impact tests

    NASA Astrophysics Data System (ADS)

    Moriničre, Freddy; Alderliesten, René; Tooski, Mehdi; Benedictus, Rinze

    2012-12-01

    An experimental study was performed on the repeated low-velocity impact behaviour of GLARE. Damage evolution in the material constituents was characterised with successive number of impacts. Records were correlated with visual inspection, ultrasound C-scan and chemical etching. The stiffness of the plate varied when cumulating the number of impacts. Damage accumulation was limited thanks to the synthesis of unidirectional composite and metal. The glass/epoxy plies with high elastic tensile strength could withstand several impacts before perforation despite delamination growth in the vicinity of the impacted area. The damage tolerant aluminium layers prevented the penetration of the projectile and avoided the expansion of delamination. This efficient mechanism preserved the structural integrity of GLARE until first aluminium cracking at the non-impacted side. Among the different failure modes, plate deformation absorbed most of the impact energy. The findings will support the development of a generic quasi-static analytical model and numerical methods.

  4. Deterministic and stochastic analysis of size effects and damage evolution in quasi-brittle materials

    Microsoft Academic Search

    M. A. Gutiérrez; R. De Borst

    1999-01-01

    Summary   This study presents some recent results on damage evolution in quasi-brittle materials including stochastic imperfections.\\u000a The material strength is described as a random field and coupled to the response. The most probable configurations of imperfections\\u000a leading to failure are sought by means of an optimisation algorithm. This allows for evaluation of the significance of different\\u000a modes and of the

  5. Finite element prediction of proximal femur fracture pattern based on orthotropic behaviour law coupled to quasi-brittle damage.

    PubMed

    Hambli, Ridha; Bettamer, Awad; Allaoui, Samir

    2012-03-01

    The purpose of this study was to develop a finite element model based on continuum damage mechanics in order to simulate the profile of the fractured area of proximal femur and the complete force-displacement curve from the beginning until complete fracture. The model was developed in term of anisotropic behaviour law coupled to quasi-brittle damage to describe the progressive crack initiation and propagation within proximal femoral. A damage law was developed and implemented into a finite element code (Abaqus) based on experimental observations. To illustrate the potential of the current approach, the right adult human femur previously investigated by Keyak and Falkinstein (Model B: male, age 61) was simulated until complete fracture under one-legged stance load. The femur fracture profile was predicted and compared to clinical observed results. Good agreements were obtained suggesting that the proposed damage model could be used correctly to simulate the force-displacement curve, the fracture type and to simulate the progressive propagation of the crack paths. Present model can contribute towards the development of diagnostic tool that can detect osteoporotic fracture for aged patients in an early stage and predict bone strength accurately. PMID:21824797

  6. Evolution of the Transplantation of Human Organ Act and law in India.

    PubMed

    Agarwal, Sanjay K; Srivastava, Rakesh K; Gupta, Sudhir; Tripathi, Samidha

    2012-07-27

    : The Government of India has established laws to conduct organ transplantation in India. The Transplantation of Human Organ Act and rules in India were promulgated in 1994 and subsequently amended in 2008 and 2011 to promote organ transplantation, including deceased organ donation, commensurate with the highest ethical principles. We have reviewed in brief the origin and evolution of the Transplantation of Human Organ Act in India with the hope that our experience in developing the laws that govern organ transplantation may be of value for others undertaking or overseeing this life-giving advance. PMID:22728294

  7. Unification of Small and Large Time Scales for Biological Evolution: Deviations from Power Law

    NASA Astrophysics Data System (ADS)

    Chowdhury, Debashish; Stauffer, Dietrich; Kunwar, Ambarish

    2003-02-01

    We develop a unified model that describes both “micro” and “macro” evolutions within a single theoretical framework. The ecosystem is described as a dynamic network; the population dynamics at each node of this network describes the “microevolution” over ecological time scales (i.e., birth, ageing, and natural death of individual organisms), while the appearance of new nodes, the slow changes of the links, and the disappearance of existing nodes accounts for the “macroevolution” over geological time scales (i.e., the origination, evolution, and extinction of species). In contrast to several earlier claims in the literature, we observe strong deviations from power law in the regime of long lifetimes.

  8. Effect of Temperature on Damage Evolution of Cr25Ni35Nb Alloy Subjected to Combined Mechanical and Environmental Degradation

    NASA Astrophysics Data System (ADS)

    Shen, Limin; Liu, Huansheng; Gong, Jianming; Geng, Luyang

    2015-07-01

    Due to combined mechanical and environmental degradation, i.e. coupled creep and carburization, Cr25Ni35Nb alloy often fails prior to the expected design life. In the present paper, based on the continuum damage mechanics, the constitutive model of coupled multi-damage factors for computing the damage evolution of Cr25Ni35Nb alloy was proposed. The damage prediction was carried out by using finite element method based on ABAQUS code. And then damage evolution processes at different operating temperatures (950 °C and 1050 °C) were simulated and the effect of service temperature on the damage evolution was discussed. The results showed that the rate of damage increased obviously with operating temperature increasing. The location with maximum damage is along the inner surface of tube, which implies that fracture begins along the inner surface of tube under the action of coupled creep and carburization damage and this is coincident with the actual observation of the failure of furnace tube.

  9. Process-induced damage evolution and management in resin transfer molding of composite panels

    NASA Astrophysics Data System (ADS)

    Kuan, Yean-Der

    2000-10-01

    Woven fiber composites made by resin transfer molding process are currently used as the primary and secondary load bearing structures in automotive and aircraft industries. A variety of defects could be evolved during the injection stage and the curing stage of the process. Improper injection conditions or unsound tool design would result in process induced damage in the form of dry spots, incomplete filling, or displacement of the fiber. In the curing stage, the process parameters of heating and cooling rates, and the temperature level at each element of the curing cycle have direct effects on the development of internal residual stresses, and shape distortion due to warpage. The work in this dissertation aims at developing numerical models to predict, characterize, and minimize process-induced damage during both the injection stage and curing stage in RTM process for woven-fiber composites. A control volume technique based on the finite difference method is used to characterize the flow behavior in resin transfer molding (RTM) of composite structures. Resin flow through fiber mats is modeled as a two-phase flow through porous media. Experimental results on flow behavior of EPON 826 epoxy resin into irregular mold cavity with fiberglass mats agree well with the present numerical simulation. Parametric analysis of several case studies using developed model illustrates the effectiveness of the flow model in investigating the flow pattern, mold filling time, dry spots formulation, and pressure distribution inside the mold. A numerical model describing the evolution of process-induced damage during curing in molded composite panels was developed. The effects of thermo-mechanical and thermo-chemical responses of the material on the evolution of damage during resin transfer molding of the panels are quantified. The developed numerical model in conjunction with an optimization module based on Simulated Annealing (SA) scheme form a useful tool for conducting a parametric design analysis for characterization and management of process-induced damage in composite panels. Experimental investigation of resin transfer molding of composite panels made of epoxy resin (EPON 826) and eight-harness graphite fiber mats, indicates that low cure temperature, moderate heating rate and high rate of cooling after cure would minimize damage during curing. Furthermore the experimental measurements are in agreement with the degree of damage predicted by the numerical models and hence verifying the effectiveness of these models. The models and methods developed in the present work are of broader applicability to process design and optimization of resin transfer molding of composite structures.

  10. Damage evolution and residual stresses in plasma-sprayed zirconia thermal barrier coatings.

    SciTech Connect

    Singh, J. P.

    1999-02-03

    Air-plasma-sprayed zirconia thermal barrier coatings were subjected to thermal cycling and residual stress evolution in thermally grown oxide scale was studied by micro- and macro-ruby fluorescence spectroscopy. The macro approach reveals that compressive stress in the oxide scale increases with increasing number of thermal cycles (and thus increasing scale thickness), reaching a value of 1.8 GPa at a scale thickness of 3-4 {micro}m (80 cycles). Micro-ruby fluorescence spectroscopy indicates that protrusions of the zirconia top coat into the bond coat act as localized areas of high stress concentration, leading to damage initiation during thermal cycling.

  11. Moving on from bland: the evolution of the law and minimally conscious patients.

    PubMed

    Heywood, Rob

    2014-01-01

    The decision in Bland centred on the withdrawal of artificial nutrition and hydration from a patient in a persistent vegetative state (PVS). Since then, a new medical condition has emerged, known as a minimally conscious state (MCS). In W v M, the Court of Protection was asked to authorise the withdrawal of artificial nutrition and hydration from a patient in a MCS. Baker J refused to grant the declaration. More recently, however, the courts were also asked to rule on the lawfulness of withholding treatment in a similar, albeit factually different, case. In the Court of Appeal decision in Aintree University Hospitals NHS Foundation Trust v David James and Others, Sir Alan Ward, with the agreement of Arden LJ and Laws LJ, granted a declaration that it would be lawful to withhold treatment. The Supreme Court then upheld this ruling, Lady Hale stating that the Court of Appeal reached the right result but for the wrong reasons. This article seeks to critically appraise the evolution of the law in regard to withdrawing treatment from MCS patients. The piece begins by explaining the differences between the two conditions of PVS and MCS and defines the law from the starting point of Bland. From here, the discussion progresses to focus on the challenges that the law has had to face in trying to keep pace with the advancing nature of medical understanding of conditions of the brain and explains how it has responded to these. The narrative then critiques the legal mechanism of best interests as it has been employed in the case law concerning MCS patients to date by analysing the various judicial perspectives on the concept. After addressing both the narrow and wide viewpoints, a conclusion is ventured as to how the balancing of best interests should be approached in respect of future MCS cases. PMID:24618294

  12. Progress in modelling the microstructural evolution in metals under cascade damage conditions

    NASA Astrophysics Data System (ADS)

    Trinkaus, H.; Singh, B. N.; Golubov, S. I.

    2000-12-01

    In recent years, it has been shown that intra-cascade clustering of vacancies and self-interstitial atoms (SIAs), differences in the thermal stability and mobility of the resulting clusters and one-dimensional (1-D) diffusional glide of SIA clusters play a key role in damage accumulation in metals under cascade damage conditions. The model taking these aspects into account (production bias model, PBM) succeeded in rationalising striking features in the microstructural evolution in pure metals, where the conventional rate theory model failed: the high overall swelling even at low dislocation densities, the enhanced swelling near grain boundaries, the decoration of dislocations with SIA loops, saturation of void growth and void lattice formation. In the present paper, the main ideas and results of these considerations are reviewed. We discuss recent work on possible effects of deviations of SIA cluster diffusion from strictly 1-D by direction changes and/or self-climb and formulate a general reaction kinetics including 1-D and 3-D cluster diffusion. Such reaction kinetics may be considered to form the basis for a general description of cascade damage accumulation in metals and complex technical alloys.

  13. Ductile Fracture Characterization of Aluminum Alloy 2024-T351 Using Damage Plasticity Theory

    Microsoft Academic Search

    Liang Xue; Tomasz Wierzbicki

    2009-01-01

    This paper presents the calibration procedure for aluminum alloy 2024-T351 using a recently developed damage plasticity theory. The damage plasticity theory consists of a full three dimensional damage evolution law where the pressure sensitivity and the Lode angle dependence are included in a fracture envelope and the equivalent plastic strain is used as a time-like variable to determine the damage

  14. Computational applications of a coupled plasticity-damage constitutive model for simulating plain concrete fracture

    Microsoft Academic Search

    Rashid K. Abu Al-Rub; Sun-Myung Kim

    2010-01-01

    A coupled plasticity-damage model for plain concrete is presented in this paper. Based on continuum damage mechanics (CDM), an isotropic and anisotropic damage model coupled with a plasticity model is proposed in order to effectively predict and simulate plain concrete fracture. Two different damage evolution laws for both tension and compression are formulated for a more accurate prediction of the

  15. Atomistic processes of damage evolution in neutron-irradiated Cu and Ni at high temperature

    NASA Astrophysics Data System (ADS)

    Shimomura, Yoshiharu; Mukouda, Ichiro; Sugio, Kenjiro; Zhao, Ping

    This paper consists of two parts. In part 1, the experimental results of damage evolution of neutron-irradiated Cu and Ni are described. In part 2, results of computer simulations are described with linkage of experimental data to explore the atomistic process of damage evolution. To study experimentally the atomistic processes of damage evolution in neutron-irradiated Cu and Ni in part 1, we prepare two types of specimens for both metals. One is as-received specimen from manufacturer. Another is a residual-gas-free specimen which is prepared by melting as-received metals in highly evacuated vacuum at 10-5 Pa. Specimens are irradiated with fission neutrons in the temperature-controlled-irradiation capsule at JMTR (Japan Materials Testing Reactor). TEM (Transmission Electron Microscope) observation shows that the dislocation structure is developed by the aggregation of interstitial clusters in irradiated metals. It is found that the number density of void which are observed in specimens, both as-received and residual-gas-free, that are irradiated to a low fluence such as 5.3 × 1018 n/cm2 at high temperature of 200°C is the same. This suggests that gas atoms are not responsible for the nucleation of voids at high temperature above 200°C in neutron-irradiated Cu and Ni. There are two characteristic temperatures of Tsft and Tvoid for the formation of stacking fault tetrahedra (sfts) and voids at high temperature, below Tsft only sft forms and above Tvoid only voids are observed. Tsft is 180°C and 250°C for Cu and Ni, respectively. Tvoid is 250°C and 270°C for Cu and Ni, respectively. In situ annealing experiments of neutron-irradiated specimen are carried out to examine the behavior of voids and sfts at high temperature. It is found that voids move as a cluster and that sfts coalesce and disappear spontaneously without shrinkage of their size. In part 2, Computer simulations of molecular dynamics and molecular statics are carried out to study the atomistic process of damage evolution in neutron-irradiated Cu and Ni at high temperatures. Interstitial clusters relax to a bundle of <110> crowdions and move one-dimensionally with a small activation energy such as 0.001eV. The migration of interstitial bundles reacts sensitively to strain fields. Interstitial clusters then form their grouping. The activation energy of an interstitial bundle to change their crowdion direction to another one is about 1 eV. This is an important factor for the evolution of dislocation structure. At high temperatures, a vacancy cluster of sfts and voids relaxes to a movable structure of string shape. Vacancy clusters move and coalesce with other clusters. The activation energy is as small as those that vacancy clusters move as a cluster without an evaporation as a single vacancy. Voids can nucleate at high temperature without trapping of any gas atoms in small vacancy clusters. Voids nucleate uniformly in specimens irradiated to a low fluence. Micro-voids migrate under the influence of strain fields and segregate near dislocation lies. At high temperature, vacancy clusters relax to the movable structure of string shape. This may explain the results of recent varying temperature irradiation at high temperature. At high temperature, vacancies are stored in a supersaturated state in a crystal as small vacancy clusters and clustering of vacancies proceed by cluster migration.

  16. Microstructural Observation and Simulation of Micro Damage Evolution of Ternary Polypropylene Blend with Ethylene-Propylene-Rubber (EPR) and Talc

    NASA Astrophysics Data System (ADS)

    Mae, Hiroyuki; Omiya, Masaki; Kishimoto, Kikuo

    An attempt has been made to study the microstructural deformation and micro damage evolution process in the thermoplastic polypropylene (PP) blended with the ethylene-propylene rubber (EPR) and talc. The in situ observation is conducted during uniaxially stretching within TEM step by step to investigate the deformation events depending on the elongation of samples. In addition, the microstructural deformation and damage evolution process were simulated by coarse-grained molecular dynamics (MD). The experimental result shows that the micro damage initiates at the interface between PP matrix and talc particle. Then, the micro void is generated there, leading to the fibrils of the PP matrix and EPR particles. The similar trend of the micro damage evolution process is obtained by MD simulation. Finally, the effects of the interfacial strength of PP-EPR and PP-talc on the microstructural damage evolution and macroscopic mechanical properties are investigated. It is indicated that increasing the interfacial strength between PP-EPR is more effective for improving the stiffness and the maximum stress, compared to the PP-talc interfacial strength. In addition, to enhance the material ductility, it is important to increase the interfacial strength of PP-EPR.

  17. Modeling the long-term evolution of the primary damage in ferritic alloys using coarse-grained methods

    SciTech Connect

    Becquart, C. S. [Universite de Lille; Domain, C. [EDF R& D, Clamart, France; Golubov, Stanislav I [ORNL; Stoller, Roger E [ORNL; Zschack, P. [Argonne National Laboratory (ANL); Barbu, Alain [CEA, Cetre de Sacaly, Gif-sur-Yvette, France; Bocquet, J.L. [CEA, Cetre de Sacaly, Gif-sur-Yvette, France; Caturla, Maria-Jose [Universidad de Alicante; Hou, Marc [Universite Libre de Bruxelles, Brussels, Belgium; Fu, Chu-chun [CEA, Cetre de Sacaly, Gif-sur-Yvette, France; Ortiz, C. J. [Laboratory Nacional de Fusion, CIEMAT; Soudi, A. [Centre Universitaire de Saida, Algeria

    2010-01-01

    Knowledge of the long-term evolution of the microstructure after introduction of primary damage is an essential ingredient in understanding mechanical property changes that occur during irradiation. Within the European integrated project PERFECT, different techniques have been developed or improved to model microstructure evolution of Fe alloys under irradiation. This review paper aims to present the current state of the art of these techniques, as developed in the project, as well as the main results obtained.

  18. Prediction of damage evolution in continuous fiber metal matrix composites subjected to fatigue loading

    SciTech Connect

    Allen, D.; Helms, K.; Lagoudas, D. [Texas A& M Univ., College Station, TX (United States)] [and others

    1995-08-01

    A life prediction model is being developed by the authors for application to metal matrix composites (MMC`s). The systems under study are continuous silicon carbide fibers imbedded in titanium matrix. The model utilizes a computationally based framework based on thermodynamics and continuum mechanics, and accounts for matrix inelasticity, damage evolution, and environmental degradation due to oxidation. The computational model utilizes the finite element method, and an evolutionary analysis of a unit cell is accomplished via a time stepping algorithm. The computational scheme accounts for damage growth such as fiber-matrix debonding, surface cracking, and matrix cracking via the inclusion of cohesive zone elements in the unit cell. These elements are located based on experimental evidence also obtained by the authors. The current paper outlines the formulation utilized by the authors to solve this problem, and recent results are discussed. Specifically, results are given for a four-ply unidirectional composite subjected to cyclic fatigue loading at 650{degrees}C both in air and inert gas. The effects of oxidation on the life of the composite are predicted with the model, and the results are compared to limited experimental results.

  19. Relating damage evolution of concrete cooled to cryogenic temperatures to permeability

    NASA Astrophysics Data System (ADS)

    Kogbara, Reginald B.; Iyengar, Srinath R.; Grasley, Zachary C.; Rahman, Syeda; Masad, Eyad A.; Zollinger, Dan G.

    2014-11-01

    Typically, 9% Ni steel is used for primary containment of liquefied natural gas (LNG). Utilization of concrete in place of 9% Ni steel for primary containment would lead to significant cost savings. Hence, this study investigates changes in the microstructure of concrete due to cryogenic freezing that would affect its relevant engineering properties for containment. The study also evaluates the effect of aggregate type on the damage potential of concrete subjected to cryogenic freezing. The aim is to investigate design methodologies to produce damage-resistant cryogenic concrete. The study employed four concrete mixture designs involving river sand as fine aggregate, and coarse aggregates with different coefficient of thermal expansion (CTE) values. Specifically, the coarse aggregates were limestone, sandstone, trap rock and lightweight aggregate. Concrete cubes were cured under water for at least 28 days and thereafter frozen from ambient (20 °C) to cryogenic temperature (-165 °C). Acoustic emission (AE) sensors were placed on the concrete cubes during freezing. X-ray computed tomography (XRCT) was employed to study the microstructure of concrete cores, before and after cryogenic freezing. The impact of the microstructural evolution thus obtained from AE and XRCT on relevant engineering properties was determined via water and chloride permeability tests. Microcrack propagation determined from AE correlated with changes in permeability. There were no observable cracks in majority of the concrete mixtures after freezing. This implies that microcracks detected via AE and increased permeability was very well distributed and smaller than the XRCT's resolution. Damage (microcracking) resistance of the concrete with different aggregates was in the order limestone ? trap rock ? lightweight aggregate ? sandstone.

  20. Damage evolution of a SiC/Ti-15-3 metal matrix composite with different heat treatments 

    E-print Network

    Miller, David Arthur

    1995-01-01

    The purpose of this thesis was to study the effects of heat treatments on the deformation mechanisms of a SiCi MMC. The damage evolution for a four ply unidirectional SiC sigma fiber/Ti 15-3 MMC was studied for a uniaxial tensile loading. Both 90...

  1. Effects of grain refinement and strength on friction and damage evolution under repeated sliding contact in nanostructured metals

    Microsoft Academic Search

    T. Hanlon; A. H. Chokshi; M. Manoharan; S. Suresh

    2005-01-01

    The early stage sliding contact fatigue behavior of nanocrystalline materials, with average and total range of grain sizes well below 100nm, was studied. The evolution of friction and damage during repeated sliding contact in the nanocrystalline metals and alloys was systematically compared and contrasted with that in ultrafine-crystalline and microcrystalline materials so as to develop a broad perspective on the

  2. Crystalline to amorphous transition and band structure evolution in ion-damaged silicon studied by spectroscopic ellipsometry

    Microsoft Academic Search

    P. K. Giri; S. Tripurasundari; G. Raghavan; B. K. Panigrahi; P. Magudapathy; K. G. M. Nair; A. K. Tyagi

    2001-01-01

    Crystalline to amorphous transition and subsequent microstructural evolution in silicon induced by Ar+-ion implantation over a wide range of ion fluences (6×1013-1×1017 cm-2) have been investigated by spectroscopic ellipsometry. In the evaluation of the optical and microstructural properties of the damaged layer, the contribution of the surface overlayer to the measured dielectric spectra was separated by fitting a multilayer model

  3. Finite element analysis of damage evolution and the prediction of the limiting draw ratio in textured aluminum sheets

    Microsoft Academic Search

    JianGuo Hu; Takashi Ishikawa; John J. Jonas

    2000-01-01

    Void nucleation and growth models have been incorporated into an elasto-plastic finite element code together with an anisotropic fourth-order strain rate potential so that damage evolution during the deep drawing of textured aluminum sheets can be analyzed. The fourth-order strain rate potential is based on the Taylor model of crystal plasticity and therefore takes the presence of texture into account.

  4. Irradiation damage in 304 and 316 stainless steels: experimental investigation and modeling. Part I: Evolution of the microstructure

    NASA Astrophysics Data System (ADS)

    Pokor, C.; Brechet, Y.; Dubuisson, P.; Massoud, J.-P.; Barbu, A.

    2004-03-01

    Irradiation damage in three austenitic stainless steels, SA 304L, CW 316 and CW Ti-modified 316, is investigated both experimentally and theoretically. The density and size of Frank loops after irradiation at 320 and 375 °C in experimental EBR II, BOR-60 and OSIRIS reactors for doses up to 40 dpa are characterized by TEM. The evolution of the initial dislocation network under irradiation is evaluated. A cluster dynamics model is proposed to account quantitatively for the experimental findings.

  5. Off-fault damage and acoustic emission distributions during the evolution of structurally complex faults over series of stick-slip events

    NASA Astrophysics Data System (ADS)

    Goebel, T. H. W.; Becker, T. W.; Sammis, C. G.; Dresen, G.; Schorlemmer, D.

    2014-06-01

    Variations in fault structure, for example, surface roughness and deformation zone width, influence the location and dynamics of large earthquakes as well as the distribution of small seismic events. In nature, changes in fault roughness and seismicity characteristics can rarely be studied simultaneously, so that little is known about their interaction and evolution. Here, we investigate the connection between fault structure and near-fault distributions of seismic events over series of stick-slip cycles in the laboratory. We conducted a set of experiments on rough faults that developed from incipient fracture surfaces. We monitored stress and seismic activity which occurred in the form of acoustic emissions (AEs). We determined AE density distributions as a function of fault normal distance based on high-accuracy hypocentre locations during subsequent interslip periods. The characteristics of these distributions were closely connected to different structural units of the faults, that is, the fault core, off-fault and background damage zone. The core deformation zone was characterized by consistently high seismic activity, whereas the off-fault damage zone displayed a power-law decay of seismic activity with increasing distance from the fault core. The exponents of the power-law-distributed off-fault activity increased with successive stick-slip events so that later interslip periods showed a more rapid spatial decay of seismic activity from the fault. The increase in exponents was strongest during the first one to three interslip periods and reached approximately constant values thereafter. The relatively rapid spatial decay of AE events during later interslip periods is likely an expression of decreasing fault zone complexity and roughness. Our results indicate a close relationship between fault structure, stress and seismic off-fault activity. A more extensive mapping of seismic off-fault activity-decay has the potential to significantly advance the understanding of fault zone properties including variations in fault roughness and stress.

  6. Cosmological Evolution of Einstein-Aether Models with Power-law-like Potential

    E-print Network

    Hao Wei; Xiao-Peng Yan; Ya-Nan Zhou

    2014-04-15

    The so-called Einstein-Aether theory is General Relativity coupled (at second derivative order) to a dynamical unit time-like vector field (the aether). It is a Lorentz-violating theory, and gained much attention in the recent years. In the present work, we study the cosmological evolution of Einstein-Aether models with power-law-like potential, by using the method of dynamical system. In the case without matter, there are two attractors which correspond to an inflationary universe in the early epoch, or a de Sitter universe in the late time. In the case with matter but there is no interaction between dark energy and matter, there are only two de Sitter attractors, and no scaling attractor exists. So, it is difficult to alleviate the cosmological coincidence problem. Therefore, we then allow the interaction between dark energy and matter. In this case, several scaling attractors can exist under some complicated conditions, and hence the cosmological coincidence problem could be alleviated.

  7. Evolution of femtosecond laser-induced damage in doped GaN thin films

    NASA Astrophysics Data System (ADS)

    Grinys, Tomas; Dmukauskas, Mantas; Š?iuka, Mindaugas; Nargelas, Saulius; Melninkaitis, Andrius

    2014-02-01

    Mg- and Si-doped GaN layers deposited by metalorganic chemical vapor deposition method were irradiated with femtosecond pulse duration laser of three different wavelengths 1,030, 515 and 343 nm. Both single and multiple shot laser induced damage thresholds of doped GaN layers were evaluated and discussed. The scanning electron microscopy employed with electron beam induced current and energy dispersive X-ray techniques were used to study laser damage morphology. It was observed that ablated area and laser-induced damage increased with irradiation fluence. The mechanism of damage generation by Gaussian beam profile laser was considered.

  8. The effect of stress rate on crack damage evolution in polystyrene and PEEK. Ph.D. Thesis

    SciTech Connect

    Gregory, B.L.

    1993-01-01

    The effects of stress rate on fatigue crack propagation (FCP) in polystyrene (PS) and polyetheretherketone (PEEK) were examined emphasizing damage evolution during fatigue fracture. Extruded and compression molded PS were studied. Craze distributions along trailing edges of successive process zone configurations in each material were self-similar. A core of dense crazing was observed in the extruded PS; no core was observed in the compression molded material. These results have important implications for the kinematics of process zone evolution in compression molded PS. Crack growth kinetics were treated as dl/dn and dl/dt. Consideration of the loading waveform and the load-time-area (LTA) revealed that LTA and rate effects couldn`t be decoupled. However, by treating the data as dl/dt the contribution of LTA constant, and the effect of stress rate was determined. Attempts were made to quantify the contributions of fatigue and creep LTA on total FCP kinetics by linear summation. While these failed, it was subsequently determined that two linear regimes separated by a characteristic period could approximate the data. The contributions of both stress rate and LTA varied above and below this characteristic period. From this analysis, the contributions of time and cycle reversal could be evaluated. Crack growth due to creep exhibited strong correlation with an exponential function compatible with stress-temperature activated processes. The crack damage evolution of PEEK as a function of stress rate during fatigue was also investigated. A brittle-ductile transition was observed characterized by a transformation at the crack tip from a rounded to a triangular (90 deg angle) crack front. The results showed that the damaged material ahead of the crack tip behaved as an elastic perfectly plastic material (plane stress conditions). This damage zone was further characterized as a volume of transformed material.

  9. EVALUATION OF DAMAGE EVOLUTION UNDER REPEATED LOADING OF POST-TENSIONED CONCRETE BEAMS BY ACOUSTIC EMISSION

    Microsoft Academic Search

    Edoardo Proverbio; Giuseppe Campanella; Vincenzo Venturi

    Recent collapses of bridges have demonstrated once again the need for reliable tools for an early monitoring of damage progression. Damages due to deterioration processes, overload, bad design, poor material quality, can grow subcritically until final collapse of the structure. AE method has been successful used for more than 20 years in industry for monitoring metal equipments (pipelines, pressure vessels,

  10. Study of the damage evolution function of tin silver copper in cycling

    NASA Astrophysics Data System (ADS)

    Qasaimeh, Awni

    The present research focused on the assessment of solder joint fatigue life in microelectronics assemblies. A general concern of any reliability engineer is whether accelerated tests are relevant to field conditions. The risk of this was minimized by developing an approach to reduce the duration of an accelerated thermal cycling test, thus allowing for the use of less accelerated test conditions. For this purpose the conventional dye and pry technique was improved and used together with artificial neural networks to measure and characterize very early stages of crack growth. The same work also demonstrated a quantitative link between thermal cycling induced recrystallization and a strong acceleration of the subsequent fatigue crack growth and failure. A new study was conducted in which different combinations of annealing and isothermal cycling provided a systematic characterization of the effects of a range of individual parameters on the recrystallization. Experiments showed the ongoing coarsening of secondary precipitates to have a clear effect on recrystallization. The rate of recrystallization was also shown not to scale with the inelastic energy deposition. This means that the most popular current thermal cycling model cannot apply to SnAgCu solder joints. Recrystallization of the Sn grains is usually not the rate limiting mechanism in isothermal cycling. The crack initiation stage often takes up a much greater fraction of the overall life, and the eventual failure of BGA joints tends to involve transgranular crack growth instead. Cycling of individual solder joints allowed for monitoring of the evolution of the solder properties and the rate of inelastic energy deposition. Both the number of cycles to crack initiation and the subsequent number of cycles to failure were shown to be determined by the inelastic energy deposition. This provides for a simple model for the extrapolation of accelerated test results to the much milder cycling amplitudes characteristic of long term service conditions based on conventional Finite Element Modeling. It also offers a critical basis for the ongoing development of a practical model to account for the often dramatic break-down of Miner's rule of linear damage accumulation under variable cycling amplitudes as expected in realistic applications.

  11. Fatigue damage evolution and property degradation of a SCS-6/Ti-22Al-23Nb orthorhombic titanium aluminide composite

    SciTech Connect

    Wang, P.C.; Jeng, S.M.; Yang, J.M. [Univ. of California, Los Angeles, CA (United States). Dept. of Materials Science and Engineering] [Univ. of California, Los Angeles, CA (United States). Dept. of Materials Science and Engineering; Russ, S.M. [Wright Lab., Wright-Patterson AFB, OH (United States). Materials Directorate] [Wright Lab., Wright-Patterson AFB, OH (United States). Materials Directorate

    1996-08-01

    The fatigue damage evolution and property degradation of a SCS-6/Ti-22Al-23Nb orthorhombic titanium aluminide composite under low cycle fatigue loading at room temperature was investigated. The fatigue test was conducted under a load-controlled mode with a load ratio (R) of 0.1, a frequency of 10 Hz, and a maximum applied stress ranging from 600 to 945 MPa. The stiffness reduction as well as the evolution of microstructural damage which includes matrix crack length, matrix crack density and interfacial debonding length as a function of fatigue cycles, and applied stresses were measured. An analytical model and a computer simulation were also developed to predict the residual stiffness and the post-fatigued tensile strength as a function of microstructural damage. Finally, a steady-state crack growth model proposed by Marshall et al. was used to predict the interfacial frictional stress and the critical crack length. Correlation between the theoretical predictions and experimental results were also discussed.

  12. Real-time in situ sensing of damage evolution in advanced fiber composites using carbon nanotube networks.

    PubMed

    Thostenson, Erik T; Chou, Tsu-Wei

    2008-05-28

    Developments in producing nanostructured materials with novel properties have opened up new opportunities in which unique functionality can be added to existing material systems. As advanced fiber composites are utilized more frequently in primary structural applications there is a key challenge to enhance the performance and reliability while reducing maintenance. As a consequence there is tremendous scientific and technical interest in the development of techniques for monitoring the health of composite structures where real-time sensing can provide information on the state of microstructural damage. In this research we utilize electrically conductive networks of carbon nanotubes as in situ sensors for detecting damage accumulation during cyclic loading of advanced fiber composites. Here we show that, by combining load and strain measurements in real-time with direct current electrical resistance measurements of the carbon nanotube network, insight can be gained toward the evolution and accumulation of damage. The resistance/strain relations show substantial hysteresis due to the formation and opening/closing of cracks during cyclic loading. Through interpreting the resistance response curves we identify a parameter that may be utilized as a quantitative measure of damage. PMID:21730592

  13. The protein folds as platonic forms: new support for the pre-Darwinian conception of evolution by natural law.

    PubMed

    Denton, Michael J; Marshall, Craig J; Legge, Michael

    2002-12-01

    Before the Darwinian revolution many biologists considered organic forms to be determined by natural law like atoms or crystals and therefore necessary, intrinsic and immutable features of the world order, which will occur throughout the cosmos wherever there is life. The search for the natural determinants of organic form-the celebrated "Laws of Form"-was seen as one of the major tasks of biology. After Darwin, this Platonic conception of form was abandoned and natural selection, not natural law, was increasingly seen to be the main, if not the exclusive, determinant of organic form. However, in the case of one class of very important organic forms-the basic protein folds-advances in protein chemistry since the early 1970s have revealed that they represent a finite set of natural forms, determined by a number of generative constructional rules, like those which govern the formation of atoms or crystals, in which functional adaptations are clearly secondary modifications of primary "givens of physics." The folds are evidently determined by natural law, not natural selection, and are "lawful forms" in the Platonic and pre-Darwinian sense of the word, which are bound to occur everywhere in the universe where the same 20 amino acids are used for their construction. We argue that this is a major discovery which has many important implications regarding the origin of proteins, the origin of life and the fundamental nature of organic form. We speculate that it is unlikely that the folds will prove to be the only case in nature where a set of complex organic forms is determined by natural law, and suggest that natural law may have played a far greater role in the origin and evolution of life than is currently assumed. PMID:12419661

  14. Evolution of damage and plasticity in titanium-based, fiber-reinforced composites

    NASA Technical Reports Server (NTRS)

    Majumdar, B. S.; Newaz, G. M.; Ellis, J. R.

    1993-01-01

    The inelastic deformation mechanisms were evaluated for a model titanium-based, fiber-reinforced composite: a beta titanium alloy (Ti-15V-3Al-3Cr-3Sn) reinforced with SiC (SCS-6) fibers. The primary emphasis of this article is to illustrate the sequence in which damage and plasticity evolved for this system. The mechanical responses and the results of detailed microstructural evaluations for the 0(8), 90(8), and +/- 45(2s) line oriented laminates are provided. It is shown that the characteristics of the reaction zone around the fiber play a very important role in the way damage and plasticity evolve, particularly in the microyield regime of deformation, and must be included in any realistic constitutive model. Fiber-matrix debonding was a major damage mode for the off-axis systems. The tension test results are also compared with the predictions of a few constitutive models.

  15. A computational model for predicting damage evolution in laminated composite plates 

    E-print Network

    Phillips, Mark Lane

    1999-01-01

    The feasibility of producing a model capable of predicting the evolution of interface degradation, matrix cracking, and delimitation at multiple sites in laminated continuous fiber composite plates subjected to monotonic loading, while still being...

  16. Stochastic Damage Evolution under Static and Fatigue Loading in Composites with Manufacturing Defects 

    E-print Network

    Huang, Yongxin

    2012-07-16

    In this dissertation, experimental investigations and theoretical studies on the stochastic matrix cracking evolution under static and fatigue loading in composite laminates with defects are presented. The presented work demonstrates a methodology...

  17. Deformation, structural changes and damage evolution in nanotwinned copper under repeated frictional contact sliding

    Microsoft Academic Search

    A. Singh; M. Dao; L. Lu; S. Suresh

    2011-01-01

    Nanotwinned metals have the potential for use as structural materials by virtue of having a combination of high strength as well as reasonable ductility and damage tolerance. In the current study, the tribological response of nanotwinned copper has been characterized under conditions of repeated frictional sliding contact with a conical tip diamond indenter. Pure ultrafine-grained copper specimens of fixed grain

  18. The Effect of Interfacial Properties on Damage Evolution in Model Composites

    E-print Network

    Sottos, Nancy R.

    in model glass fiber reinforced epoxy matrix composites. The composite properties were varied by changing, such as holes, notches, lap joints, and incidental damage, will affect the residual strength and lifetime: fiber failure and pullout, matrix cracking, interface debonding, and shear band devel- opment [1

  19. Teaching about Controversial Issues: Resolving Conflict between Creationism and Evolution through Law-Related Education.

    ERIC Educational Resources Information Center

    Morishita, Ford

    1991-01-01

    Presents a unit on evolution and creation theories in which students explore the legal issues surrounding the teaching of evolution and creation in biology. Students write preliminary essays, study conflict resolution techniques, and conduct a moot trial of the Scopes case of 1925. A course outline is provided. (MDH)

  20. Collateral Damage: the Implications of Utrecht Star Cluster Astrophysics for Galaxy Evolution

    NASA Astrophysics Data System (ADS)

    Kruijssen, J. M. D.

    2013-01-01

    Until the early 2000s, the research portfolio of the Astronomical Institute in Utrecht (SIU) did not include galaxy evolution. Somewhat serendipitously, this changed with the advent of the star cluster group. In only a few years, a simple framework was developed to describe and quantify the properties of dynamically evolving star cluster populations. Since then, the ‘Utrecht cluster disruption model’ has shown that the galactic environment plays an important role in setting the evolution of stellar clusters. From this simple result, it follows that cluster populations bear some imprint of the characteristics and histories of their host galaxies, and that star clusters can be used to trace galaxy evolution—an aim for which the Utrecht star cluster models were never designed, but which they are well-capable of fulfilling. I review some of the work in this direction, with a strong emphasis on the contributions from the SIU.

  1. Damage evolution in acetabular reconstructs under physiological testing in a saline environment.

    PubMed

    Tozzi, G; Lupton, C; Heaton-Adegbile, P; Tong, J

    2012-01-10

    Damage development in cemented acetabular reconstructs has been studied under a combined cyclic loading block representative of routine activities in a saline environment. A custom-made environmental chamber was designed and installed on the Portsmouth hip simulator to allow testing of acetabular reconstructs in a wet condition for the first time. Damage was monitored and detected by scanning at selected loading intervals using micro-focus computed tomography (?CT). The preliminary results show that, although, as in dry cases, debonding at the bone-cement interface defined the failure of the cement fixation, the combination of mechanical loading and saline environment significantly affected the damage initiation and development, with drastically reduced survival lives of the reconstructs. Debonding was found to be initiated at the bone-cement interface near the rim of the acetabular cup, or DeLee zone I, in wet condition, as opposed to initiation in DeLee zone II near the dome region in dry cases. The survival time of the reconstruct in wet condition is less than 10% of that in dry condition under a given applied hip contact force. PMID:22018582

  2. The evolution of Mexico City's abortion laws: from public morality to women's autonomy.

    PubMed

    Madrazo, Alejandro

    2009-09-01

    Before 2000, Mexico City's criminal laws prohibited induced abortion to maintain public morality. The Criminal Code considered abortion by accident or in cases of rape not criminal, and criminal but excusable-and therefore not punishable-in certain cases not endangering public morality, such as medical necessity to save the woman's life. In 2000, the Criminal Code was reformed expanding exceptions from criminal liability, particularly in cases of danger to a woman's health or where fetal survival was at risk. In 2004, Mexico City enacted its own law, effectively decriminalizing consensual abortion in cases of rape, fetal malformation, and risk to the woman's health. A 2007 reform further decriminalized all consensual abortion within the first 12 weeks of pregnancy, and required public hospitals to provide abortion and family planning services. In August 2008, the Supreme Court of Mexico ruled Mexico City's 2007 liberalization of abortion law constitutional. PMID:19545866

  3. The Source of Alabama’s Abundance of Arbitration Cases: Alabama’s Bizarre Law of Damages for Mental Anguish

    E-print Network

    Simpson, W. Scott; Ware, Stephen J.; Willard, Vickie M.

    2004-01-01

    This Article gives an overview of arbitration litigation in Alabama, including the evolution of mental anguish jurisprudence in contract cases, especially with regard to the automobile and home industries; a proposal to ...

  4. Evolution Equations with Non-Linear Constitutive Laws and Memory E ects

    E-print Network

    Louisiana State University

    Universität Dresden 11th October 2000 Abstract Abstract: Evolution equations are considered as operator, or for speci#28;c models in one dimension of space, such as in Kurbanov, [7], again for Maxwell's equations

  5. PREDICTION OF PROXIMAL FEMORAL FRACTURE BY USING MECHANICAL QUASI-BRITTLE DAMAGE COUPLED WITH ANISOTROPIC BEHAVIOUR LAW

    E-print Network

    Boyer, Edmond

    applied stress, fracture toughness to determine the crack initiation and crack propagation behavior if if PREDICTION OF PROXIMAL FEMORAL FRACTURE BY USING MECHANICAL QUASI-BRITTLE DAMAGE COUPLED WITH ANISOTROPIC : abettamer2003@yahoo.com Introduction A femoral fracture caused by the osteoporosis becomes increasingly

  6. Higher-order hydrodynamics: Extended Fick's Law, evolution equation, and Bobylev's instability

    Microsoft Academic Search

    Justino R. Madureira; Aurea R. Vasconcellos; Roberto Luzzi

    Microscopic descriptions of hydrodynamics, that is, deri- vation of kinetic equations from classical or quantum me- chanics and containing kinetic ~or transport! coefficients written in terms of correlation functions, is a traditional problem of long standing. An important aspect is the deriva- tion of constitutive laws which express thermodynamic fluxes ~or currents as those of matter and of energy! in

  7. Contact behavior evolution induced by damage growth in radio-frequency microelectromechanical system switches

    NASA Astrophysics Data System (ADS)

    Wu, Y.; Peroulis, D.

    2015-02-01

    This study provides a two-contact-event model to explain the evolution of the contact behavior of microelectromechanical system (MEMS) switches through their lifetime. The succession of two dynamic contact events is carefully considered during actuation inspired by experimental observations. The contact between the MEMS switch tip and the drain can be treated as an effective contact between an elastic hemisphere and a rigid plane. If the first contact event results in elastic deformation, the effective hemisphere will fully recover. Consequently, the subsequent contact event also produces elastic deformation. If, on the other hand, the first contact event induces elastoplastic or plastic deformation, a residual depth will be produced between the hemisphere and the rigid plane. The contact force of the subsequent contact event can be significantly reduced due to this additional residual depth. With the growth of residual depth during the switch cycling process, the modeling results show three possible situations of contact radius evolution: (1) The contact radius increases to a maximum value and then decreases to zero; (2) the contact radius increases to one local maximum value; then decreases to a local minimum value; subsequently increases again to another maximum value, and finally decreases to zero; and (3) the contact radius increases to one maximum value and then decreases to zero; after an intermittent response, the contact radius increases again to another maximum value and finally decreases to zero. Furthermore, the Maxwell spreading formula is applied to determine the contact resistance which is inversely proportional to the contact radius. Three situations of contact resistance evolution corresponding to the evolution of contact radius are obtained. All three situations are also observed and validated by the experimental results.

  8. Damage evolution in acetabular replacements under long-term physiological loading conditions.

    PubMed

    Wang, J-Y; Heaton-Adegbile, P; New, A; Hussell, J G; Tong, J

    2009-05-29

    Damage development in cemented acetabular replacements has been studied in bovine pelvic bones under long-term physiological loading conditions, including normal walking, stair climbing and a combined block loading with representative routine activities. The physiological loading conditions were achieved using a specially designed hip simulator for fixation endurance testing. Damage was detected and monitored using micro-CT scanning at regular intervals of the experiments, and verified by microscopic studies post testing. The results show that debonding at the bone-cement interface defined the failure of cement fixation in all cases, and debondings initiated near the dome of the acetabulum in the superior-posterior quadrant, consistent with the high-stress region identified from the finite element analysis of implanted acetabular models Zant, N.P., Heaton-Adegbile, P., Hussell, J.G., Tong, J., 2008b. In-vitro fatigue failure of cemented acetabular replacements-a hip simulator study. Journal of Biomechanical Engineering, Transactions of the ASME, 130, 021019-1-9]; [Tong, J., Zant, N.P., Wang, J-Y., Heaton-Adegbile, P., Hussell, J.G., 2008. Fatigue in cemented acetabulum. International Journal of Fatigue, 30(8), 1366-1375]. PMID:19345357

  9. An explicit finite element formulation for dynamic strain localization and damage evolution in metals

    SciTech Connect

    Mourad, Hashem M [Los Alamos National Laboratory; Bronkhorst, Curt A [Los Alamos National Laboratory; Addessio, Francis L [Los Alamos National Laboratory

    2010-12-16

    An explicit finite element formulation, used to study the behavior and failure mechanisms of metallic materials under high strain rate loading, is presented. The formulation is based on the assumed-strain approach of Fish and Belytschko [1988], which allows localization bands to be embedded within an element, thereby alleviating mesh sensitivity and reducing the required computational effort. The behavior of the material outside localization bands (and of the virgin material prior to the onset of strain localization) is represented using a Gurson-type coupled plasticity-damage model based on the work of Johnson and Addessio [1988]. Assuming adiabatic conditions, the response of the localization band material is represented by a set of constitutive equations for large elasticviscoplastic deformations in metals at high strain rates and high homologous temperatures (see Brown et al. [1989]). Computational results are compared to experimental data for different metallic alloys to illustrate the advantages of the proposed modeling strategy.

  10. Models for predicting damage evolution in metal matrix composites subjected to cyclic loading

    SciTech Connect

    Allen, D.H.; Hurtado, L.D.; Helms, K.L.E. [Texas A and M Univ., College Station, TX (United States). Center for Mechanics of Composites

    1995-03-01

    A thermomechanical analysis of a continuous fiber metal matrix composite (MMC) subjected to cyclic loading is performed herein. The analysis includes the effects of processing induced residual thermal stresses, matrix inelasticity, and interface cracking. Due to these complexities, the analysis is performed computationally using the finite element method. Matrix inelasticity is modelled with a rate dependent viscoplasticity model. Interface fracture is modelled by the use of a nonlinear interface constitutive model. The problem formulation is summarized, and results are given for a four-ply unidirectional SCS-6/{beta}21S titanium composite under high temperature isothermal mechanical fatigue. Results indicate rate dependent viscoplasticity can be a significant mechanism for dissipating the energy available for damage propagation, thus contributing to improved ductility of the composite. Results also indicate that the model may be useful for inclusion in life prediction methodologies for MMC`s.

  11. The public philosophy of John Dewey and the evolution of law enforcement 

    E-print Network

    Patterson, Michael Lewis

    2004-09-30

    we make judgments of the activities we do, we could reach a more objective measurement of our progress. The same applies to our techniques. Improvements in manufacturing, or in the case of police, skills in performing law enforcement duties..., computers, pistols, and impact weapons; for skills there are improved interview techniques and better takedown methods; for thinking, there are diverse methods of finding solutions such as problem solving, case management and incident command. When making...

  12. Is Power Law Scaling a quantitative description of Darwin Theory of Evolution?

    Microsoft Academic Search

    Hari Mohan Gupta; José Roberto Campanha

    2003-01-01

    In the present work, via computational simulation we study the statistical distribution of people versus number of steps acquired by them in a learning process, considering Darwin classical theory of evolution, i.e. competition, learning and survival for the fittest. We consider that learning ability is normally distributed. We found that the number of people versus step acquired by them in

  13. Toward a Theory of Statutory Evolution: The Federalization of Environmental Law

    Microsoft Academic Search

    E. Donald Elliott; Bruce A Ackerman; John C Millian

    1985-01-01

    Let us begin by renouncing two of the more ambitious implications of thetitle. No, we do not believe that any single theory can do justice to all varietiesof statutory development. Nor do we believe that everything worth sayingabout the processes by which statutes change can be captured by analogy tobiological evolution.Just as each human being has a unique life history,

  14. Defect production, annealing kinetics and damage evolution in alpha-Fe: an atomic-scale computer simulation

    NASA Astrophysics Data System (ADS)

    Soneda, N.; Diaz de La Rubia, T.

    1998-05-01

    Radiation-induced microstructural and compositional changes in solids are governed by the interaction between the fraction of defects that escape their nascent cascade and the material. We use a combination of molecular dynamics (MD) and kinetic Monte Carlo (KMC) simulations to calculate the damage production efficiency and the fraction of freely migrating defects in alpha-Fe at 600 K. MD simulations provide information on the nature of the primary damage state as a function of recoil energy, and on the kinetics and energetics of point defects and small defect clusters. The KMC simulations use as input the MD results and provide a description of defect diffusion and interaction over long time and length scales. For the MD simulations, we employ the analytical embedded-atom potential developed by Johnson and Oh for alpha-Fe, including a modification of the short-range repulsive interaction. We use MD to calculate the diffusivities of point defects and small defect clusters and the binding energy of small vacancy and interstitial clusters. We show that, at temperatures below about 600 K, small interstitial clusters form prismatic dislocation loops which migrate in one dimension with a very low activation energy Ea 0.1eV. We also present results of MD simulations of displacement cascades at energies up to 20 keV. The results show that, for recoil energies above 5 keV, interstitials are produced in the form of small prismatic loops with a high probability, but vacancies are not. The MD results are then combined with a KMC simulation of defect interaction and diffusion, which includes the one-dimensional glide of small interstitial loops. The results provide a clear picture of the damage annealing process and show that for 20keV cascades the escape probability for both vacancies and interstitials is about 65%. This results in a freely migrating defect production efficiency of 20% of the total defect production predicted by the modified Kinchin-Pease model (the displacements per atom standard). The capability of the hybrid MD-KMC method for carrying out long length and time scale simulations of damage evolution in irradiated materials is emphasized.

  15. Is Power Law Scaling a quantitative description of Darwin Theory of Evolution?

    Microsoft Academic Search

    Hari Mohan Gupta; Dpto Física

    2003-01-01

    In the present work, via computational simulation we study the statistical\\u000adistribution of people versus number of steps acquired by them in a learning\\u000aprocess, considering Darwin classical theory of evolution, i.e. competition,\\u000alearning and survival for the fittest. We consider that learning ability is\\u000anormally distributed. We found that the number of people versus step acquired\\u000aby them in

  16. Fatigue damage analysis of unidirectional metal matrix composites

    Microsoft Academic Search

    Serge Kruch; Nicolas Carrčre; Jean-Louis Chaboche

    2006-01-01

    The paper deals with the non-linear analysis of industrial components subjected to strong thermo-mechanical cyclic loads. Two kinds of damages must be taken into account: the first one being a “constitutive damage” which will dominate the low cycle fatigue (LCF) regime and whose evolution law will be coupled to the elasto-viscoplastic model. The second one will be a “classical” fatigue

  17. Topographic signatures and a general transport law for deep-seated landslides in a landscape evolution model

    NASA Astrophysics Data System (ADS)

    Booth, Adam M.; Roering, Josh J.; Rempel, Alan W.

    2013-06-01

    A fundamental goal of studying earth surface processes is to disentangle the complex web of interactions among baselevel, tectonics, climate, and rock properties that generate characteristic landforms. Mechanistic geomorphic transport laws can quantitatively address this goal, but no widely accepted law for landslides exists. Here we propose a transport law for deep-seated landslides in weathered bedrock and demonstrate its utility using a two-dimensional numerical landscape evolution model informed by study areas in the Waipaoa catchment, New Zealand, and the Eel River catchment, California. We define a non-dimensional landslide number, which is the ratio of the horizontal landslide flux to the vertical tectonic flux, that characterizes three distinct landscape types. One is dominated by stochastic landsliding, whereby discrete landslide events episodically erode material at rates exceeding the long-term uplift rate. Another is characterized by steady landsliding, in which the landslide flux at any location remains constant through time and is greatest at the steepest locations in the catchment. The third is not significantly affected by landsliding. In both the "stochastic landsliding" and "steady landsliding" regimes, increases in the non-dimensional landslide number systematically reduce catchment relief and widen valley spacing, producing long, low angle hillslopes despite high uplift rates. The stochastic landsliding regime captures the frequent observation that deep-seated landslides produce large sediment fluxes from small areal extents while being active only a fraction of the time. We suggest that this model is adaptable to a wide range of geologic settings and is useful for interpreting climate-driven changes in landslide behavior.

  18. From Migmatites to Plutons: Power Law Relationships in the Evolution of Magmatic Bodies

    NASA Astrophysics Data System (ADS)

    Soesoo, Alvar; Bons, Paul D.

    2015-07-01

    Magma is generated by partial melting from micrometre-scale droplets at the source and may accumulate to form >100 km-scale plutons. Magma accumulation thus spans well over ten orders of magnitude in scale. Here we provide measurements of migmatitic leucosomes and granitic veins in drill cores from the Estonian Proterozoic basement and outcrops at Masku in SW Finland and Montemor-o-Novo, central Portugal. Despite the differences in size and number of measured leucosomes and magmatic veins, differences in host rock types and metamorphic grades, the cumulative width distribution of the studied magmatic leucosomes/veins follows a power law with exponents usually between 0.7 and 1.8. Published maps of the SE Australian Lachlan Fold Belt were used to investigate the distribution of granitoid pluton sizes. The granites occupy ca. 22 % of the 2.6 × 105 km2 area. The cumulative pluton area distributions show good power law distributions with exponents between 0.6 and 0.8 depending on pluton area group. Using the self-affine nature of pluton shapes, it is possible to estimate the total volume of magma that was expelled from the source in the 2.6 × 105 km2 map area, giving an estimated 0.8 km3 of magma per km2. It has been suggested in the literature that magma batches in the source merge to form ever-bigger batches in a self-organized way. This leads to a power law for the cumulative distribution of magma volumes, with an exponent m V between 1 for inefficient melt extraction, and 2/3 for maximum accumulation efficiency as most of the volume resides in the largest batches that can escape from the source. If m V ? 1, the mass of the magma is dominated by small batches; in case m = 2/3, about 50 % of all magma in the system is placed in a single largest batch. Our observations support the model that the crust develops a self-organized critical state during magma generation. In this state, magma batches accumulate in a non-continuous, step-wise manner to form ever-larger accumulations. There is no characteristic length or time scale in the partial melting process or its products. Smallest melt segregations and >km-scale plotuns form the end members of a continuous chain of mergers of magma batches.

  19. Conservation Laws and the Multiplicity Evolution of Spectra at the Relativistic Heavy Ion Collider

    E-print Network

    Zbigniew Chaj?cki; Mike Lisa

    2009-01-09

    Transverse momentum distributions in ultra-relativistic heavy ion collisions carry considerable information about the dynamics of the hot system produced. Direct comparison with the same spectra from $p+p$ collisions has proven invaluable to identify novel features associated with the larger system, in particular, the "jet quenching" at high momentum and apparently much stronger collective flow dominating the spectral shape at low momentum. We point out possible hazards of ignoring conservation laws in the comparison of high- and low-multiplicity final states. We argue that the effects of energy and momentum conservation actually dominate many of the observed systematics, and that $p+p$ collisions may be much more similar to heavy ion collisions than generally thought.

  20. Review: Evolution of stacking fault tetrahedra and its role in defect accumulation under cascade damage conditions [review article

    NASA Astrophysics Data System (ADS)

    Singh, B. N.; Golubov, S. I.; Trinkaus, H.; Edwards, D. J.; Eldrup, M.

    2004-07-01

    In order to help understand the evolution of stacking fault tetrahedra (SFTs) in a cascade producing irradiation environment, the available information on the behaviour of SFTs observed under different experimental conditions has been briefly reviewed. Effects of thermal annealing and irradiations on the stability of pre-existing SFTs produced by quenching and aging are also included in the review. Some results on the effects of thermal annealing of irradiation-induced SFTs are presented and discussed. The analysis of these observations leads to three significant conclusions: (a) during irradiation SFTs produced in the cascades are likely to interact with vacancies, self-interstitial atoms (SIAs) and SIA clusters, (b) interaction with SIAs and their clusters may cause both shrinkage and transformation of SFTs into Frank loops and (c) both during irradiation and annealing the lifetime of SFTs is determined not only by their thermal stability but also by their stability against transformation to loops. These facts must be taken into account in the theoretical treatments of damage accumulation.

  1. Deformation Failure Characteristics of Coal Body and Mining Induced Stress Evolution Law

    PubMed Central

    Wen, Zhijie; Wen, Jinhao; Shi, Yongkui; Jia, Chuanyang

    2014-01-01

    The results of the interaction between coal failure and mining pressure field evolution during mining are presented. Not only the mechanical model of stope and its relative structure division, but also the failure and behavior characteristic of coal body under different mining stages are built and demonstrated. Namely, the breaking arch and stress arch which influence the mining area are quantified calculated. A systematic method of stress field distribution is worked out. All this indicates that the pore distribution of coal body with different compressed volume has fractal character; it appears to be the linear relationship between propagation range of internal stress field and compressed volume of coal body and nonlinear relationship between the range of outburst coal mass and the number of pores which is influenced by mining pressure. The results provide theory reference for the research on the range of mining-induced stress and broken coal wall. PMID:24967438

  2. Deformation failure characteristics of coal body and mining induced stress evolution law.

    PubMed

    Wen, Zhijie; Qu, Guanglong; Wen, Jinhao; Shi, Yongkui; Jia, Chuanyang

    2014-01-01

    The results of the interaction between coal failure and mining pressure field evolution during mining are presented. Not only the mechanical model of stope and its relative structure division, but also the failure and behavior characteristic of coal body under different mining stages are built and demonstrated. Namely, the breaking arch and stress arch which influence the mining area are quantified calculated. A systematic method of stress field distribution is worked out. All this indicates that the pore distribution of coal body with different compressed volume has fractal character; it appears to be the linear relationship between propagation range of internal stress field and compressed volume of coal body and nonlinear relationship between the range of outburst coal mass and the number of pores which is influenced by mining pressure. The results provide theory reference for the research on the range of mining-induced stress and broken coal wall. PMID:24967438

  3. Propagation of continuum damage in a viscoelastic ice bar

    SciTech Connect

    Shin, J.G. (Seoul National Univ. (Korea, Republic of). Dept. of Naval Architecture and Ocean Engineering); Karr, D.G. (Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Naval Architecture and Marine Engineering)

    1994-05-01

    An initial value problem of a semi-infinite nonlinear viscoelastic bar is solved with continuum damage evolution. The evolution law of the continuum damage for a viscoelastic material is used in order to explore the propagation of two crushing mechanisms: grain boundary cracking and transgranular cracking. Using the method of characteristics, the speed of propagation is found to be dependent on the continuum damage. On the wave front, the delayed elastic strain is zero, and only the continuum damage due to the transgranular cracking evolves. A finite difference method is developed to solve the governing equations on the obtained characteristic lines, and gives a stable solution for the propagation of the stress, strain, and damage. Numerical results are obtained and discussed using the material properties of polycrystalline ice.

  4. An investigation of the effects of history dependent damage in time dependent fracture mechanics: nano-scale studies of damage evolution

    SciTech Connect

    Brust, F.W. (Bud) Jr; Mohan, R.; Yang, Y.P.; Oh, J.; Katsube, N.

    2002-12-01

    High-temperature operation of technical engineering systems is critical for system efficiency, and will be a key driver in the future US DOE energy policy. Developing an understanding of high-temperature creep and creep-fatigue failure processes is a key driver for the research work described here. The focus is on understanding the high-temperature deformation and damage development on the nano-scale (50 to 500 nm) level. The high-temperature damage development process, especially with regard to low and high cyclic loading, which has received little attention to date, is studied. Damage development under cyclic loading develops in a fashion quite different from the constant load situation. The development of analytical methodologies so that high-temperature management of new systems can be realized is the key goal of this work.

  5. Vortex Structure and Evolution within Bow Echoes. Part I: Single-Doppler and Damage Analysis of the 29 June 1998 Derecho

    Microsoft Academic Search

    Nolan T. Atkins; Justin M. Arnott; Ron W. Przybylinski; Ray A. Wolf; Bradley D. Ketcham

    2004-01-01

    Single-Doppler radar along with damage observations are examined to investigate the structural evolution of vortices observed within the 29 June 1998 derecho event that propagated through southeastern Iowa into central and eastern Illinois. A total of 13 meso-g-scale vortices observed primarily at low levels (0-3 km AGL) along the leading edge of the convective system were detected by the Weather

  6. Strain rate dependency of the shear properties of a highly oriented thermoplastic composite material using a contacting displacement measurement methodology—Part B: shear damage evolution

    Microsoft Academic Search

    N. Papadakis; N. Reynolds; M. W. Pharaoh; P. K. C. Wood; G. F. Smith

    2004-01-01

    This paper is the second part of a two-part series on the strain rate dependency of the shear properties of a glass\\/polypropylene composite laminate material. In this study the Ladevéze composite material model is used to characterise the shear damage evolution for crosshead displacement rates varying over three orders of mag-nitude. The research was carried out as part of the

  7. Postbuckling investigations of piezoelectric microdevices considering damage effects.

    PubMed

    Sun, Zhigang; Wang, Xianqiao

    2014-01-01

    Piezoelectric material has been emerging as a popular building block in MEMS devices owing to its unique mechanical and electrical material properties. However, the reliability of MEMS devices under buckling deformation environments remains elusive and needs to be further explored. Based on the Talreja's tensor valued internal state damage variables as well as the Helmhotlz free energy of piezoelectric material, a constitutive model of piezoelectric materials with damage is presented. The Kachanvo damage evolution law under in-plane compressive loads is employed. The model is applied to the specific case of the postbuckling analysis of the piezoelectric plate with damage. Then, adopting von Karman's plate theory, the nonlinear governing equations of the piezoelectric plates with initial geometric deflection including damage effects under in-plane compressive loads are established. By using the finite difference method and the Newmark scheme, the damage evolution for damage accumulation is developed and the finite difference procedure for postbuckling equilibrium path is simultaneously employed. Numerical results show the postbuckling behaviors of initial flat and deflected piezoelectric plates with damage or no damage under different sets of electrical loading conditions. The effects of applied voltage, aspect ratio of plate, thick-span ratio of plate, damage as well as initial geometric deflections on the postbuckling behaviors of the piezoelectric plate are discussed. PMID:24618774

  8. Postbuckling Investigations of Piezoelectric Microdevices Considering Damage Effects

    PubMed Central

    Sun, Zhigang; Wang, Xianqiao

    2014-01-01

    Piezoelectric material has been emerging as a popular building block in MEMS devices owing to its unique mechanical and electrical material properties. However, the reliability of MEMS devices under buckling deformation environments remains elusive and needs to be further explored. Based on the Talreja's tensor valued internal state damage variables as well as the Helmhotlz free energy of piezoelectric material, a constitutive model of piezoelectric materials with damage is presented. The Kachanvo damage evolution law under in-plane compressive loads is employed. The model is applied to the specific case of the postbuckling analysis of the piezoelectric plate with damage. Then, adopting von Karman's plate theory, the nonlinear governing equations of the piezoelectric plates with initial geometric deflection including damage effects under in-plane compressive loads are established. By using the finite difference method and the Newmark scheme, the damage evolution for damage accumulation is developed and the finite difference procedure for postbuckling equilibrium path is simultaneously employed. Numerical results show the postbuckling behaviors of initial flat and deflected piezoelectric plates with damage or no damage under different sets of electrical loading conditions. The effects of applied voltage, aspect ratio of plate, thick-span ratio of plate, damage as well as initial geometric deflections on the postbuckling behaviors of the piezoelectric plate are discussed. PMID:24618774

  9. Does the universe obey the energy conservation law by a constant mass or an increasing mass with radius during its evolution?

    E-print Network

    Akinbo Ojo

    2008-10-09

    How the energy conservation law is obeyed by the universe during its evolution is an important but not yet unanimously resolved question. Does the universe have a constant mass during its evolution or has its mass been increasing with its radius? Here, we evaluate the two contending propositions within the context of the Friedmann equations and the standard big bang theory. We find that though both propositions appeal to the Friedmann equations for validity, an increasing mass with increasing radius is more in harmony with the thermal history of the big bang model. In addition, temperature and flatness problems that plague the constant mass proposal are mitigated by the increasing mass with radius proposal. We conclude that the universe has been increasing in mass and radius in obedience to the energy conservation law.

  10. Effect of Yarn Sizes on the Tensile Damage Evolution of a C/SiC Composite Fabricated by Chemical Vapor Infiltration

    NASA Astrophysics Data System (ADS)

    Wang, Yiqiang; Zhang, Litong; Cheng, Laifei

    2011-04-01

    The damage evolutions of C/SiC composites fabricated by chemical vapor infiltration with two different sizes of yarns were compared by cyclic tensile load/unload tests accompanied with the acoustic emission (AE) monitoring. The results show that an inflexion was observed in both the evolution of hysteresis characteristics and the corresponding AE curve for composite with fine yarns, which is, however, absent for composite with coarse yarns, suggesting that the former is much closer to the tough material than the latter one. Felicity effect was observed for both composites, which is more pronounced for the composite with coarse yarns due to the large yarn sizes leading to more matrix debris inside the yarns.

  11. Lattice strain and damage evolution of 9-12/%Cr ferritic/martensitic steel during in situ tensile test by x-ray diffraction and small angle scattering.

    SciTech Connect

    Pan, X.; Wu, X.; Mo, K.; Chen, X,; Almer, J. D.; Ilavsky, J.; Haeffner, D. R.; Stubbins, J. F.; X-Ray Science Division; Univ. of Illinois

    2010-01-01

    In situ X-ray diffraction and small angle scattering measurements during tensile tests were performed on 9-12% Cr ferritic/martensitic steels. The lattice strains in both particle and matrix phases, along two principal directions, were directly measured. The load transfer between particle and matrix was calculated based on matrix/particle elastic mismatch, matrix plasticity and interface decohesion. In addition, the void or damage evolution during the test was measured using small angle X-ray scattering. By combining stress and void evolution during deformation, the critical interfacial strength for void nucleation was determined, and compared with pre-existing void nucleation criteria. These comparisons show that models overestimate the measured critical strength, and require a larger particle size than measured to match the X-ray observations.

  12. Modeling Fatigue Damage in Long-Fiber Thermoplastics

    SciTech Connect

    Nguyen, Ba Nghiep; Kunc, Vlastimil; Bapanapalli, Satish K.

    2009-10-30

    This paper applies a fatigue damage model recently developed for injection-molded long-fiber thermoplastics (LFTs) to predict the modulus reduction and fatigue lifetime of glass/polyamide 6,6 (PA6,6) specimens. The fatigue model uses a multiscale mechanistic approach to describe fatigue damage accumulation in these materials subjected to cyclic loading. Micromechanical modeling using a modified Eshelby-Mori-Tanaka approach combined with averaging techniques for fiber length and orientation distributions is performed to establish the stiffness reduction relation for the composite as a function of the microcrack volume fraction. Next, continuum damage mechanics and a thermodynamic formulation are used to derive the constitutive relations and the damage evolution law. The fatigue damage model has been implemented in the ABAQUS finite element code and has been applied to analyze fatigue of the studied glass/PA6,6 specimens. The predictions agree well with the experimental results.

  13. Evolution

    NSDL National Science Digital Library

    This virtual evolution exhibit at the University of California at Berkeley (Museum of Paleontology) combines several of the best resources we've evaluated, such as Phylogenetic Systematics and the Talk Origins Archive, among others. In addition, the Evolution Website provides information on the Theory of Evolution (with links to further information including Timeline of Evolutionary Thought; Systematics; Dinosaur Discoveries; and Vertebrate Flight) and the History of Evolutionary Thought (including dozens of biographical summaries). For educators or students interested in reviewing or learning about evolution in a historical context, this Website will be of much use.

  14. Investigation of a Novel NDE Method for Monitoring Thermomechanical Damage and Microstructure Evolution in Ferritic-Martensitic Steels for Generation IV Nuclear Energy Systems

    SciTech Connect

    Nagy, Peter

    2013-09-30

    The main goal of the proposed project is the development of validated nondestructive evaluation (NDE) techniques for in situ monitoring of ferritic-martensitic steels like Grade 91 9Cr-1Mo, which are candidate materials for Generation IV nuclear energy structural components operating at temperatures up to ~650{degree}C and for steam-generator tubing for sodium-cooled fast reactors. Full assessment of thermomechanical damage requires a clear separation between thermally activated microstructural evolution and creep damage caused by simultaneous mechanical stress. Creep damage can be classified as "negligible" creep without significant plastic strain and "ordinary" creep of the primary, secondary, and tertiary kind that is accompanied by significant plastic deformation and/or cavity nucleation and growth. Under negligible creep conditions of interest in this project, minimal or no plastic strain occurs, and the accumulation of creep damage does not significantly reduce the fatigue life of a structural component so that low-temperature design rules, such as the ASME Section III, Subsection NB, can be applied with confidence. The proposed research project will utilize a multifaceted approach in which the feasibility of electrical conductivity and thermo-electric monitoring methods is researched and coupled with detailed post-thermal/creep exposure characterization of microstructural changes and damage processes using state-of-the-art electron microscopy techniques, with the aim of establishing the most effective nondestructive materials evaluation technique for particular degradation modes in high-temperature alloys that are candidates for use in the Next Generation Nuclear Plant (NGNP) as well as providing the necessary mechanism-based underpinnings for relating the two. Only techniques suitable for practical application in situ will be considered. As the project evolves and results accumulate, we will also study the use of this technique for monitoring other GEN IV materials. Through the results obtained from this integrated materials behavior and NDE study, new insight will be gained into the best nondestructive creep and microstructure monitoring methods for the particular mechanisms identified in these materials. The proposed project includes collaboration with a national laboratory partner and the results will also serve as a foundation to guide the efforts of scientists in the DOE laboratory, university, and industrial communities concerned with the technological challenges of monitoring creep and microstructural evolution in materials planned to be used in Generation IV Nuclear Energy Systems.

  15. Does Species Evolution Follow Scale Laws? First Applications of the Scale Relativity Theory to Fossil and Living-beings

    Microsoft Academic Search

    Jean Chaline

    2010-01-01

    We have demonstrated, using the Cantor dust method, that the statistical distribution of appearance and disappearance of rodents\\u000a species (Arvicolid rodent radiation in Europe) follows power laws strengthening the evidence for a fractal structure set.\\u000a Self-similar laws have been used as model for the description of a huge number of biological systems. With Nottale we have\\u000a shown that log-periodic behaviors

  16. DNA Damages as a Depolymerization Process

    NASA Astrophysics Data System (ADS)

    Ochoa, Juan G. Diaz; Wulkow, Michael

    The damage of DNA chains by environmental factors like radiation or chemical pollutants is a topic that has been frequently explored from an experimental and a theoretical perspective. Such damages, like the damage of the strands of a DNA chain, are toxic for the cell and can induce mutagenesis or apoptosis. Several models make strong assumptions for the distribution of damages; for instance a frequent supposition is that these damages are Poisson distributed. [L. Ma, J. J. Wagner, W. Hu, A. J. Levine and G. A. Stolovitzki, Proc. Natl. Acad. Sci.PNAS 102, 14266 (2005).] Only few models describe in detail the damage and the mechanisms associated to the formation and evolution of this damage distribution [H. Nikjoo, P. O'neill and D. T. Goodhead, Radiat. Res. 156, 577 (2001).] Nevertheless, such models do not include the repair processes which are continuously active inside the cell. In this work we present a novel model, based on a depolymerization process, describing the distribution of damages on DNA chains coupled to the dynamics associated to its repair processes. The central aim is not to give a final and comprehensive model, but a hint to represent in more detail the complex dynamics involved in the damage and repair of DNA. We show that there are critical parameters associated to this repair process, in particular we show how critical doses can be relevant in deciding whether the cell continues its repair process or starts apoptosis. We also find out that the damage concentration is related to the dose via a power law relation.

  17. Temperature activated absorption during laser-induced damage: The evolution of laser-supported solid-state absorption fronts

    SciTech Connect

    Carr, C W; Bude, J D; Shen, N; Demange, P

    2010-10-26

    Previously we have shown that the size of laser induced damage sites in both KDP and SiO{sub 2} is largely governed by the duration of the laser pulse which creates them. Here we present a model based on experiment and simulation that accounts for this behavior. Specifically, we show that solid-state laser-supported absorption fronts are generated during a damage event and that these fronts propagate at constant velocities for laser intensities up to 4 GW/cm{sup 2}. It is the constant absorption front velocity that leads to the dependence of laser damage site size on pulse duration. We show that these absorption fronts are driven principally by the temperature-activated deep sub band-gap optical absorptivity, free electron transport, and thermal diffusion in defect-free silica for temperatures up to 15,000K and pressures < 15GPa. In addition to the practical application of selecting an optimal laser for pre-initiation of large aperture optics, this work serves as a platform for understanding general laser-matter interactions in dielectrics under a variety of conditions.

  18. An X-ray Radiography Study of the Effect of Thermal Cycling on Damage Evolution in Large-Area Sn-3.5Ag Solder Joints

    NASA Astrophysics Data System (ADS)

    Muralidharan, Govindarajan; Kurumaddali, Kanth; Kercher, Andrew K.; Walker, Larry; Leslie, Scott G.

    2013-02-01

    There is a need for next-generation, high-performance power electronic packages and systems utilizing wide-band-gap devices to operate at high temperatures in automotive and electricity transmission applications. Sn-3.5Ag solder is a candidate for use in such packages with potential maximum operating temperatures of about 200°C. However, there is a need to understand the thermal cycling reliability of Sn-3.5Ag solders subject to such high-temperature operating conditions. The results of a study on the damage evolution occurring in large-area Sn-3.5Ag solder joints between silicon dies and direct bonded copper substrates with Au/Ni-P metallization subject to thermal cycling between 200°C and 5°C are presented in this paper. Interface structure evolution and damage accumulation were followed using high-resolution X-ray radiography, cross-sectional optical and scanning electron microscopies, and X-ray microanalysis in these joints for up to 3000 thermal cycles. Optical and scanning electron microscopy results showed that the stresses introduced by the thermal cycling result in cracking and delamination at the copper-intermetallic compound interface. X-ray microanalysis showed that stresses due to thermal cycling resulted in physical cracking and breakdown of the Ni-P barrier layer, facilitating Cu-Sn interdiffusion. This interdiffusion resulted in the formation of Cu-Sn intermetallic compounds underneath the Ni-P layer, subsequently leading to delamination between the Ni-rich layer and Cu-Sn intermetallic compounds.

  19. Evolution of patients' complaints in a French university hospital: is there a contribution of a law regarding patients' rights?

    PubMed Central

    Giugliani, Camila; Gault, Nathalie; Fares, Valia; Jegu, Jérémie; Trolli, Sergio Eleni dit; Biga, Julie; Vidal-Trecan, Gwenaelle

    2009-01-01

    Background Legislative measures have been identified as one effective way of changing attitude or behaviour towards health care. The aim of this study was to describe trends in patients' complaints for medical issues; to evaluate the contribution of a law regarding patients' rights, and to identify factors associated to patients' perception of a medical error. Methods Patients with a complaint letter for medical issues in a French university hospital were included. Trends in complaint rates were analysed. Comparisons were made between a first (1998–2000) and a second (2001–2004) time period, before and after the diffusion of the law, and according to the perception of a medical error. Results Complaints for medical issues increased from 1998 to 2004. Of 164 complaints analysed, 66% were motivated by the perception of a medical error (47% during the first time period vs. 73% during the second time period; p = 0.001). Error or delay in diagnosis/treatment and surgical/medical complication were the main reasons for complaints. Surgical departments had the higher number of complaints. Second time period, substandard care, disability, and adverse effect of a health product were independently associated with the perception of a medical error, positively for the formers, and negatively for the latter. Conclusion This study revealed an increase with time in the number of complaints for medical issues in a university hospital, as well as an increase in the perception of a medical error after the passing of a law regarding patients' rights in France. PMID:19660131

  20. Modeling the long-term evolution of the primary damage in ferritic alloys using coarse-grained methods

    SciTech Connect

    Stoller, Roger E [ORNL; Becquart, C. S. [Universite de Lille; Domain, C. [EDF R& D, Clamart, France; Hou, Marc [Universite Libre de Bruxelles, Brussels, Belgium; Soudi, A. [Centre Universitaire de Saida, Algeria; Malerba, Lorenzo [Belgian Nuclear Research Centre, SCK-CEN

    2010-01-01

    Atomic displacement cascades in solids are complex phenomena, the outcome of which can be statistically characterised by properties such as their spatial extent, morphology and the spatial correlation of defects. Some properties scale in a simple way with parameters such as the cascade energy, others have limited variability with energy, for example point defect cluster size distributions. Taking advantage of the latter invariance, we use Object Kinetic Monte Carlo simulations to demonstrate that most properties of displacement cascade play no significant role in the evolution of point defect cluster size distributions after long enough time. It is suggested that reliable long-term predictions are possible, when using only the self-interstitial and vacancy cluster size distributions from low energy displacement cascades as building blocks to represent the complete spectrum of cascade energies obtained under neutron irradiation conditions. This is shown on the basis of recursive properties of displacement cascades evidenced for the first time and taking only approximately into account the average volumes in which vacancies and self-interstitial atoms are confined. The model has been successfully used to simulate the evolution of point defect clusters in iron for displacement rates in the range of 10-6 dpa/s and doses of the order of 0.1 dpa. The applicability beyond this range and to more complex materials is discussed.

  1. Evolution of radiographic joint damage in rituximab-treated versus TNF-treated rheumatoid arthritis cases with inadequate response to TNF antagonists

    PubMed Central

    Finckh, Axel; Möller, Burkhard; Dudler, Jean; Walker, Ulrich A; Kyburz, Diego; Gabay, Cem

    2012-01-01

    Background Observational studies have suggested that patients with rheumatoid arthritis (RA) who experience inadequate response to anti-tumour necrosis factor (anti-TNF) agents respond more favourably to rituximab (RTX) than to an alternative anti-TNF agent. However, the relative effectiveness of these agents on long-term outcomes, particularly in radiographic damage, remains unclear. Objective To compare the effectiveness of RTX against anti-TNF agents in preventing joint damage in patients with RA who have experienced inadequate response to at least one prior anti-TNF agent. Methods This is a prospective cohort study within the Swiss registry of patients with RA who discontinued at least one anti-TNF agent and subsequently received either RTX or an alternative anti-TNF agent. The primary outcome, progression of radiographic joint erosions (Ratingen erosion score)over time, and the secondary outcome, functional disability (Health Assessment Questionnaire Disability Index), were analysed using regression models for longitudinal data and adjusted for potential confounders. Results Of the 371 patients included, 104 received RTX and 267 received an alternative anti-TNF agent. During the 2.6-year median follow-up period, the rates of Ratingen erosion score progression were similar between patients taking RTX and patients taking an alternative anti-TNF agent (p=0.67). The evolution of the Health Assessment Questionnaire score was statistically significantly better in the RTX group (p=0.016), but the magnitude of the effect was probably not clinically relevant. Conclusion This observational study suggests that RTX is as effective as an alternative anti-TNF agent in preventing erosions in patients with RA who have previously experienced inadequate response to anti-TNF agents. PMID:22419773

  2. An anisotropic gradient damage model for quasi-brittle materials

    Microsoft Academic Search

    Ellen Kuhl; Ekkehard Ramm; René de Borst

    2000-01-01

    An anisotropic continuum damage model based on the microplane concept is elaborated. Scalar damage laws are formulated on several individual microplanes representing the planes of potential failure. These uniaxial constitutive laws can be cast into a fourth-order damage formulation such that anisotropy of the overall constitutive law is introduced in a natural fashion. Strain gradients are incorporated in the constitutive

  3. Conservation laws and multiplicity evolution of spectra at energies available at the BNL Relativistic Heavy Ion Collider

    SciTech Connect

    Chajecki, Zbigniew; Lisa, Mike [Department of Physics, Ohio State University, 191 West Woodruff Ave., Columbus, Ohio 43210 (United States)

    2009-03-15

    Transverse momentum distributions in ultrarelativistic heavy ion collisions carry considerable information about the dynamics of the hot system produced. Direct comparison with the same spectra from p+p collisions has proved invaluable in identifying novel features associated with the larger system, in particular, the 'jet quenching' at high momentum and the apparently much stronger collective flow dominating the spectral shape at low momentum. We point out possible hazards of ignoring conservation laws in the comparison of high- and low-multiplicity final states. We argue that the effects of energy and momentum conservation actually dominate many of the observed systematics, and that p+p collisions may be much more similar to heavy ion collisions than generally thought.

  4. Evolution of different dual-use concepts in international and national law and its implications on research ethics and governance.

    PubMed

    Rath, Johannes; Ischi, Monique; Perkins, Dana

    2014-09-01

    This paper provides an overview of the various dual-use concepts applied in national and international non-proliferation and anti-terrorism legislation, such as the Biological and Toxin Weapons Convention, the Chemical Weapons Convention and United Nations Security Council Resolution 1540, and national export control legislation and in relevant codes of conduct. While there is a vast literature covering dual-use concepts in particular with regard to life sciences, this is the first paper that incorporates into such discussion the United Nations Security Council Resolution 1540. In addition, recent developments such as the extension of dual-use export control legislation in the area of human rights protection are also identified and reviewed. The discussion of dual-use concepts is hereby undertaken in the context of human- and/or national-security-based approaches to security. This paper discusses four main concepts of dual use as applied today in international and national law: civilian versus military, peaceful versus non-peaceful, legitimate versus illegitimate and benevolent versus malevolent. In addition, the usage of the term to describe positive technology spin-offs between civilian and military applications is also briefly addressed. Attention is also given to the roles civil society and research ethics may play in the governance of dual-use sciences and technologies. PMID:24497004

  5. Temporal Variation of Aerosol Properties at a Rural Continental Site and Study of Aerosol Evolution through Growth Law Analysis

    NASA Technical Reports Server (NTRS)

    Wang, Jian; Collins, Don; Covert, David; Elleman, Robert; Ferrare, Richard A.; Gasparini, Roberto; Jonsson, Haflidi; Ogren, John; Sheridan, Patrick; Tsay, Si-Chee

    2006-01-01

    Aerosol size distributions were measured by a Scanning Mobility Particle Sizer (SMPS) onboard the CIRPAS Twin Otter aircraft during 16 flights at the Southern Great Plains (SGP) site in northern central Oklahoma as part of the Aerosol Intensive Operation period in May, 2003. During the same period a second SMPS was deployed at a surface station and provided continuous measurements. Combined with trace gas measurements at the SGP site and back-trajectory analysis, the aerosol size distributions provided insights into the sources of aerosols observed at the SGP site. High particle concentrations, observed mostly during daytime, were well correlated with the sulfur dioxide (SO2) mixing ratios, suggesting nucleation involving sulfuric acid is likely the main source of newly formed particles at the SGP. Aerosols within plumes originating from wildfires in Central America were measured at the surface site. Vertically compact aerosol layers, which can be traced back to forest fires in East Asia, were intercepted at altitudes over 3000 meters. Analyses of size dependent particle growth rates for four periods during which high cloud coverage was observed indicate growth dominated by volume controlled reactions. Sulfate accounts for 50% to 72% of the increase in aerosol volume concentration; the rest of the volume concentration increase was likely due to secondary organic species. The growth law analyses and meteorological conditions indicate that the sulfate was produced mainly through aqueous oxidation of SO2 in clouds droplets and hydrated aerosol particles.

  6. Preventing Persons Affected by Serious Mental Illnesses from Obtaining Firearms: The Evolution of Law, Policy, and Practice in Massachusetts.

    PubMed

    Silver, James; Fisher, William H; Silver, Emily

    2015-06-01

    A history of commitment to a mental health facility disqualifies applicants for gun licenses. Identifying such a history has become increasingly complex as the locus of confinement has become more diversified and privatized. In Massachusetts, prior to 2014, the databases used to identify individuals who would be disqualified on such grounds had not contemporaneously matched the evolution of the state's mental health systems. A survey of Massachusetts police chiefs, who, as in many jurisdictions, are charged with certifying qualification, indicates that some have broadened the scope of their background checks to include the experience of their officers with respect to certain applicants. The survey identifying these patterns, conducted in 2014, preceded by one month significant legislative reforms that mandate the modification of the reporting into a centralized database commitments to all types of mental health and substance use facilities, thus allowing identification of all commitments occurring in the state. The anticipated utilization of a different database mechanism, which has parallels in several other states, potentially streamlines the background check process, but raises numerous concerns that need to be addressed in developing and using such databases. Copyright © 2015 John Wiley & Sons, Ltd. PMID:25737302

  7. Courtside: A Damaging Lesson

    ERIC Educational Resources Information Center

    Zirkel, Perry A.

    2004-01-01

    This case presents a costly lesson for teachers and for districts that include a liquidated, or stipulated, damages clause in their teacher employment contracts. Although the court enforced the clause in this case, in this well-reasoned recent decision and in most of the much older, canvassed case law from other jurisdictions, the answer to the…

  8. Evolution equation of population genetics: relation to the density-matrix theory of quasiparticles with general dispersion laws.

    PubMed

    Bezák, V

    2003-02-01

    The Waxman-Peck theory of population genetics is discussed in regard of soil bacteria. Each bacterium is understood as a carrier of a phenotypic parameter p. The central objective is the calculation of the probability density with respect to p, Phi(p,t;p(0)), of the carriers living at time t>0, provided that initially at t(0)=0, all bacteria carried the phenotypic parameter p(0)=0. The theory involves two small parameters: the mutation probability mu and a parameter gamma involved in a function w(p) defining the fitness of the bacteria to survive the generation time tau and give birth to an offspring. The mutation from a state p to a state q is defined by a Gaussian with a dispersion sigma(2)(m). The author focuses our attention on a function phi(p,t) which determines uniquely the function Phi(p,t;p(0)) and satisfies a linear equation (Waxman's equation). The Green function of this equation is mathematically identical with the one-particle Bloch density matrix, where mu characterizes the order of magnitude of the potential energy. (In the x representation, the potential energy is proportional to the inverted Gaussian with the dispersion sigma(2)(m)). The author solves Waxman's equation in the standard style of a perturbation theory and discusses how the solution depends on the choice of the fitness function w(p). In a sense, the function c(p)=1-w(p)/w(0) is analogous to the dispersion function E(p) of fictitious quasiparticles. In contrast to Waxman's approximation, where c(p) was taken as a quadratic function, c(p) approximately gammap(2), the author exemplifies the problem with another function, c(p)=gamma[1-exp(-ap(2))], where gamma is small but a may be large. The author shows that the use of this function in the theory of the population genetics is the same as the use of a nonparabolic dispersion law E=E(p) in the density-matrix theory. With a general function c(p), the distribution function Phi(p,t;0) is composed of a delta-function component, N(t)delta(p), and a blurred component. When discussing the limiting transition for t--> infinity, the author shows that his function c(p) implies that N(t)-->N( infinity ) not equal 0 in contrast with the asymptotics N(t)-->0 resulting from the use of Waxman's function c(p) approximately p(2). PMID:12636721

  9. Medium energy ion scattering analysis of the evolution and annealing of damage and associated dopant redistribution of ultra shallow implants in Si

    NASA Astrophysics Data System (ADS)

    van den Berg, J. A.; Reading, M. A.; Armour, D. G.; Carter, G.; Zalm, P. C.; Bailey, P.; Noakes, T. C. Q.

    As junction depths in advanced semiconductor devices move to below 20 nm, the process of disorder evolution during ion implantation at ultra low energies becomes increasingly influenced by the surface. This may also hold for shallow regrowth and dopant redistribution processes during subsequent thermal annealing of the substrate. The investigation of these near-surface processes requires analytical techniques with a depth resolution of?1 nm. Medium energy ion scattering (MEIS) has the unique capability of simultaneously providing quantitative, high-resolution depth distributions of implant disorder (displaced Si lattice atoms) and of implanted atoms, albeit not of light species. We report here a comparative MEIS investigation into the growth mode of shallow disordered/amorphised layers during?1 keV B+ and 2.5 keV As+ ion implantation into Si. In both cases the growth of the damage depth profiles differs significantly from the energy deposition function, as it is strongly determined on the one hand by the proximity of the surface acting as a nucleation site for migrating point defects formed during implantation, which results in planar growth of the amorphous layer, and on the other by the dynamic annealing processes operating at room temperature. When such defect recombination processes are inhibited, e.g. for low dose, ultra shallow 200 eV B+ implants, MEIS shows that defect production yields exceeding the Kinchin-Pease model predictions are achieved. For As implants, a correlation is observed between the movement of the As and the depth of the growing, planar amorphous layer. Thermal annealing of As implanted samples at different temperatures and durations leads to solid phase epitaxial regrowth. During regrowth, MEIS shows that there is a close correlation between damage dissolution, the movement of nearly half of the As dopant into substitutional sites and the snowploughing of a fraction of the As in front of the advancing amorphous/crystalline interface leading to the formation of a less than 1 nm wide As pile-up layer trapped under the oxide.

  10. Interaction Between Dynamic Rupture And Off-fault Brittle Damage

    NASA Astrophysics Data System (ADS)

    Xu, S.; Ampuero, J.; Ben-Zion, Y.; Lyakhovsky, V.

    2008-12-01

    The high stress concentration at the front of a dynamic rupture is expected to produce rock damage (reduction of elastic moduli) in the material surrounding the main fault plane. Off-fault yielding and energy absorption in the damage process should reduce the amplitude of the ground motion. However, the reduced elastic moduli in the damaged zone can amplify locally the motion and create a waveguide that may allow the motion to propagate with little geometric attenuation. In addition, the asymmetric damage generated in the in- plane rupture mode may produce bimaterial interfaces that can reduce the frictional dissipation and increase the radiation efficiency. Previous studies incorporated plastic yielding in simulations of dynamic rupture (Andrews, 1975, 2005; Ben- Zion and Shi, 2005; Templeton et al., 2008) while keeping the elastic moduli unchanged. In this work we examine the dynamics of ruptures and generated motion in a model consisting of a frictional fault in a medium governed by a continuum damage rheology that accounts for the evolution of elastic moduli (e.g. Lyakhovsky and Ben-Zion, 2008). We perform numerical simulations based on the Spectral Element Method to study how the parameters of the friction law, damage rheology and background stress control the rate of growth of the off-fault damage zone, the rupture speed, the energy partition to various components, and the maximum slip rate and ground motion. We compare the peak motion generated with our damage model to results of analogous simulations using Coulomb plastic yielding. Off-fault damage is of special importance for ruptures along faults that separate rocks of different elastic properties, because they can generate asymmetric patterns of material degradation that might be observable in the field. We plan to perform simulations involving velocity-weakening friction and off-fault damage associated with pre-existing bimaterial faults.

  11. A model for high temperature creep of single crystal superalloys based on nonlocal damage and viscoplastic material behavior

    NASA Astrophysics Data System (ADS)

    Trinh, B. T.; Hackl, K.

    2014-07-01

    A model for high temperature creep of single crystal superalloys is developed, which includes constitutive laws for nonlocal damage and viscoplasticity. It is based on a variational formulation, employing potentials for free energy, and dissipation originating from plasticity and damage. Evolution equations for plastic strain and damage variables are derived from the well-established minimum principle for the dissipation potential. The model is capable of describing the different stages of creep in a unified way. Plastic deformation in superalloys incorporates the evolution of dislocation densities of the different phases present. It results in a time dependence of the creep rate in primary and secondary creep. Tertiary creep is taken into account by introducing local and nonlocal damage. Herein, the nonlocal one is included in order to model strain localization as well as to remove mesh dependence of finite element calculations. Numerical results and comparisons with experimental data of the single crystal superalloy LEK94 are shown.

  12. Water, law, science

    NASA Astrophysics Data System (ADS)

    Narasimhan, T. N.

    2008-01-01

    SummaryIn a world with water resources severely impacted by technology, science must actively contribute to water law. To this end, this paper is an earth scientist's attempt to comprehend essential elements of water law, and to examine their connections to science. Science and law share a common logical framework of starting with a priori prescribed tenets, and drawing consistent inferences. In science, observationally established physical laws constitute the tenets, while in law, they stem from social values. The foundations of modern water law in Europe and the New World were formulated nearly two thousand years ago by Roman jurists who were inspired by Greek philosophy of reason. Recognizing that vital natural elements such as water, air, and the sea were governed by immutable natural laws, they reasoned that these elements belonged to all humans, and therefore cannot be owned as private property. Legally, such public property was to be governed by jus gentium, the law of all people or the law of all nations. In contrast, jus civile or civil law governed private property. Remarkably, jus gentium continues to be relevant in our contemporary society in which science plays a pivotal role in exploiting vital resources common to all. This paper examines the historical roots of modern water law, follows their evolution through the centuries, and examines how the spirit of science inherent in jus gentium is profoundly influencing evolving water and environmental laws in Europe, the United States and elsewhere. In a technological world, scientific knowledge has to lie at the core of water law. Yet, science cannot formulate law. It is hoped that a philosophical understanding of the relationships between science and law will contribute to their constructively coming together in the service of society.

  13. Constitutive modeling of solid propellant materials with evolving microstructural damage

    NASA Astrophysics Data System (ADS)

    Xu, F.; Aravas, N.; Sofronis, P.

    Solid propellants are composite materials with complex microstructure. In a generic form, the material consists of polymeric binder, crystal oxidizer (e.g., ammonium perchlorate), and fuel particles (e.g., aluminum). Severe stressing and extreme temperatures induce damage which is manifested in particle cracking, dewetting along particle/polymer interfaces, void nucleation and growth. Damage complicates the overall constitutive response of a solid propellant over and above the complexities associated with the differing constitutive properties of the particle and binder phases. Using rigorous homogenization theory for composite materials, we propose a general 3-D nonlinear macroscopic constitutive law that models microstructural damage evolution upon straining through continuous void formation and growth. The law addresses the viscous deformation rate within the framework of additive decomposition of the deformation rate and the concept of back stress is used to improve the model performance in stress relaxation. No restriction is placed on the magnitude of the strains. Experimental data from the standard relaxation and uniaxial tension tests are used to calibrate the model parameters in the case of a high elongation solid propellant. It is emphasized that the model parameters are descriptors of individual phase constitutive response and criticality conditions for particle decohesion which can systematically be determined through experiment. The model is used to predict the response of the material under more complex loading paths and to investigate the effect of crack tip damage on the mechanical behavior of a compact tension fracture specimen.

  14. Progressive Damage Analysis of Laminated Composite (PDALC)-A Computational Model Implemented in the NASA COMET Finite Element Code

    NASA Technical Reports Server (NTRS)

    Lo, David C.; Coats, Timothy W.; Harris, Charles E.; Allen, David H.

    1996-01-01

    A method for analysis of progressive failure in the Computational Structural Mechanics Testbed is presented in this report. The relationship employed in this analysis describes the matrix crack damage and fiber fracture via kinematics-based volume-averaged variables. Damage accumulation during monotonic and cyclic loads is predicted by damage evolution laws for tensile load conditions. The implementation of this damage model required the development of two testbed processors. While this report concentrates on the theory and usage of these processors, a complete list of all testbed processors and inputs that are required for this analysis are included. Sample calculations for laminates subjected to monotonic and cyclic loads were performed to illustrate the damage accumulation, stress redistribution, and changes to the global response that occur during the load history. Residual strength predictions made with this information compared favorably with experimental measurements.

  15. Damage In Rock Massives, Evidences From Microseismic Monitoring and Numerical Modelling

    NASA Astrophysics Data System (ADS)

    Amitrano, D.; Gruber, S.; Girard, L.

    2014-12-01

    Damage is an active process in rock massives that can progressively lead to their collapse. Microseismic monitoring appears as a powerful tool for detecting damage and identifying the parameters controlling its occurrence parameter. In this presentation, we first present results of seismic monitoring performed on different sites and highlighting different control parameters, including freezing/thawing cycling, long term creeping, rainfall. These observations reveal common features as power-law distribution of the seismic event size and of their temporal distribution. The evolution of these distributions can be used for forecasting the failure, as successfully tested on a cliff that undergone macroscopic failure. In a second part we present numerical modelling of damage that successfully reproduce the major part of the in-situ observations. The simulations based on short or long term damage and taking into account the action of fluids, have been applied to realistic cases and show promising results in good agreements with field observation.

  16. A simplified implementation of a gradient-enhanced damage model with transient length scale effects

    NASA Astrophysics Data System (ADS)

    Saroukhani, S.; Vafadari, R.; Simone, A.

    2013-06-01

    Gradient-enhanced damage models with constant gradient activity suffer from spurious damage growth at high deformation levels. This issue was resolved by Geers et al. (Comput Methods Appl Mech Eng 160(1-2):133-153, 1998) by expressing the gradient activity parameter as a function of the local equivalent strain at the expense of adding one set of degrees of freedom to those of the standard model. In this contribution, a new formulation of the gradient-enhanced damage model with variable length scale is presented which eliminates the need for the extra set of degrees of freedom. The merits of the proposed formulation are demonstrated, and the choice of the damage evolution law and its impact on the model performance are discussed.

  17. Progressive Damage Analysis of Laminated Composite (PDALC) (A Computational Model Implemented in the NASA COMET Finite Element Code). 2.0

    NASA Technical Reports Server (NTRS)

    Coats, Timothy W.; Harris, Charles E.; Lo, David C.; Allen, David H.

    1998-01-01

    A method for analysis of progressive failure in the Computational Structural Mechanics Testbed is presented in this report. The relationship employed in this analysis describes the matrix crack damage and fiber fracture via kinematics-based volume-averaged damage variables. Damage accumulation during monotonic and cyclic loads is predicted by damage evolution laws for tensile load conditions. The implementation of this damage model required the development of two testbed processors. While this report concentrates on the theory and usage of these processors, a complete listing of all testbed processors and inputs that are required for this analysis are included. Sample calculations for laminates subjected to monotonic and cyclic loads were performed to illustrate the damage accumulation, stress redistribution, and changes to the global response that occurs during the loading history. Residual strength predictions made with this information compared favorably with experimental measurements.

  18. Tornado Damage!

    NSDL National Science Digital Library

    2014-09-18

    Students learn about tornadoes, the damage they cause, and how to rate tornadoes. Specifically, students investigate the Enhanced Fujita Damage Scale of tornado intensity, and use it to complete a mock engineering analysis of damage caused by a tornado. Additional consideration is given to tornado warning systems and how these systems can be improved to be safer. Lastly, students learn basic tornado safety procedures.

  19. Effect of stochasticity on the damage accumulation in solids

    Microsoft Academic Search

    Vadim V. Silberschmidt; Jean-Louis Chaboche

    1994-01-01

    The influence of stochasticity of external action on damage accumulation is studied in terms of continuum damage mechanics (CDM). The accounting for micromechanisms is based on the introduction of additional parameters-traditional damage and shear damage. Kinetic equations of damage accumulation are reformulated to account for the stochastic component of loading. The characteristic features of the evolution of the ensembles of

  20. Damage evolution analysis in mortar, during compressive loading using acoustic emission and X-ray tomography: Effects of the sand\\/cement ratio

    Microsoft Academic Search

    H. Elaqra; N. Godin; G. Peix; M. R'Mili; G. Fantozzi

    2007-01-01

    This paper explores the use of acoustic emission (AE) and X-ray tomography to identify the mechanisms of damage and the fracture process during compressive loading on concrete specimens. Three-dimensional (3D) X-ray tomography image analysis was used to observe defects of virgin mortar specimen under different compressive loads. Cumulative AE events were used to evaluate damage process in real time according

  1. 48 CFR 422.302 - Liquidated damages and overtime pay.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...LABOR LAWS TO GOVERNMENT ACQUISITIONS Contract Work Hours and Safety Standards Act 422.302 Liquidated damages and...damages due under section 104(c) of the Contract Work Hours and Safety Standards Act, and to take remedial action,...

  2. 48 CFR 422.302 - Liquidated damages and overtime pay.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...LABOR LAWS TO GOVERNMENT ACQUISITIONS Contract Work Hours and Safety Standards Act 422.302 Liquidated damages and...damages due under section 104(c) of the Contract Work Hours and Safety Standards Act, and to take remedial action,...

  3. Helmet Laws

    MedlinePLUS

    ... universal motorcycle helmet laws to qualify for certain highway safety funds. By 1975, all but three had ... here. For more information, consult the appropriate State Highway Safety Office . State Motorcyclists Bicyclists Universal Helmet Law ( ...

  4. Elastic-Plastic Constitutive Equation of WC-Co Cemented Carbides with Anisotropic Damage

    SciTech Connect

    Hayakawa, Kunio; Nakamura, Tamotsu; Tanaka, Shigekazu [Department of Mechanical Engineering, Shizuoka University, 3-5-1 Johoku, Hamamatsu 432-8561 (Japan)

    2007-05-17

    Elastic-plastic constitutive equation of WC-Co cemented carbides with anisotropic damage is proposed to predict a precise service life of cold forging tools. A 2nd rank symmetric tensor damage tensor is introduced in order to express the stress unilaterality; a salient difference in uniaxial behavior between tension and compression. The conventional framework of irreversible thermodynamics is used to derive the constitutive equation. The Gibbs potential is formulated as a function of stress, damage tensor, isotropic hardening variable and kinematic hardening variable. The elastic-damage constitutive equation, conjugate forces of damage, isotropic hardening and kinematic hardening variable is derived from the potential. For the kinematic hardening variable, the superposition of three kinematic hardening laws is employed in order to improve the cyclic behavior of the material. For the evolution equation of the damage tensor, the damage is assumed to progress by fracture of the Co matrix - WC particle interface and by the mechanism of fatigue, i.e. the accumulation of microscopic plastic strain in matrix and particles. By using the constitutive equations, calculation of uniaxial tensile and compressive test is performed and the results are compared with the experimental ones in the literature. Furthermore, finite element analysis on cold forward extrusion was carried out, in which the proposed constitutive equation was employed as die insert material.

  5. Environmental Laws

    NSDL National Science Digital Library

    United States. Environmental Protection Agency.

    The Environmental Protection Agency (EPA) has compiled a list of the seventeen major environmental laws which govern their agency and the programs they administer. Users can link to summaries or the full-text version of each law, provided, for the most part, by Cornell University. Those new to the subject may want to visit the Introduction to Laws and Regulations section, which explains how environmental laws come into being. Additional sections of the site--Regulations and Proposed Rules, Codified Regulations, and Current Legislation and Laws--link to further information such as Federal Register documents issued by EPA and the Code of Federal Regulations database.

  6. Multi-wavelength Observations of the Spatio-temporal Evolution of Solar Flares with AIA/SDO. II. Hydrodynamic Scaling Laws and Thermal Energies

    NASA Astrophysics Data System (ADS)

    Aschwanden, Markus J.; Shimizu, Toshifumi

    2013-10-01

    In this study we measure physical parameters of the same set of 155 M- and X-class solar flares observed with AIA/SDO as analyzed in Paper I, by performing a differential emission measure analysis to determine the flare peak emission measure EM p , peak temperature Tp , electron density np , and thermal energy E th, in addition to the spatial scales L, areas A, and volumes V measured in Paper I. The parameter ranges for M- and X-class flares are log (EM p ) = 47.0-50.5, Tp = 5.0-17.8 MK, np = 4 × 109-9 × 1011 cm-3, and thermal energies of E th = 1.6 × 1028-1.1 × 1032 erg. We find that these parameters obey the Rosner-Tucker-Vaiana (RTV) scaling law T_p^2 \\propto n_p L and HvpropT 7/2 L -2 during the peak time tp of the flare density np , when energy balance between the heating rate H and the conductive and radiative loss rates is achieved for a short instant and thus enables the applicability of the RTV scaling law. The application of the RTV scaling law predicts power-law distributions for all physical parameters, which we demonstrate with numerical Monte Carlo simulations as well as with analytical calculations. A consequence of the RTV law is also that we can retrieve the size distribution of heating rates, for which we find N(H)vpropH -1.8, which is consistent with the magnetic flux distribution N(?)vprop?-1.85 observed by Parnell et al. and the heating flux scaling law FH vpropHLvpropB/L of Schrijver et al.. The fractal-diffusive self-organized criticality model in conjunction with the RTV scaling law reproduces the observed power-law distributions and their slopes for all geometrical and physical parameters and can be used to predict the size distributions for other flare data sets, instruments, and detection algorithms.

  7. MULTI-WAVELENGTH OBSERVATIONS OF THE SPATIO-TEMPORAL EVOLUTION OF SOLAR FLARES WITH AIA/SDO. II. HYDRODYNAMIC SCALING LAWS AND THERMAL ENERGIES

    SciTech Connect

    Aschwanden, Markus J. [Lockheed Martin Advanced Technology Center, Org. ADBS, Bldg. 252, 3251 Hanover St., Palo Alto, CA 94304 (United States); Shimizu, Toshifumi, E-mail: aschwanden@lmsal.com, E-mail: shimizu.toshifumi@isas.jaxa.jp [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo, Sagamihara, Kanagawa 252-5210 (Japan)

    2013-10-20

    In this study we measure physical parameters of the same set of 155 M- and X-class solar flares observed with AIA/SDO as analyzed in Paper I, by performing a differential emission measure analysis to determine the flare peak emission measure EM{sub p} , peak temperature T{sub p} , electron density n{sub p} , and thermal energy E{sub th}, in addition to the spatial scales L, areas A, and volumes V measured in Paper I. The parameter ranges for M- and X-class flares are log (EM{sub p}) = 47.0-50.5, T{sub p} = 5.0-17.8 MK, n{sub p} = 4 × 10{sup 9}-9 × 10{sup 11} cm{sup –3}, and thermal energies of E{sub th} = 1.6 × 10{sup 28}-1.1 × 10{sup 32} erg. We find that these parameters obey the Rosner-Tucker-Vaiana (RTV) scaling law T{sub p}{sup 2}?n{sub p} L and H?T {sup 7/2} L {sup –2} during the peak time t{sub p} of the flare density n{sub p} , when energy balance between the heating rate H and the conductive and radiative loss rates is achieved for a short instant and thus enables the applicability of the RTV scaling law. The application of the RTV scaling law predicts power-law distributions for all physical parameters, which we demonstrate with numerical Monte Carlo simulations as well as with analytical calculations. A consequence of the RTV law is also that we can retrieve the size distribution of heating rates, for which we find N(H)?H {sup –1.8}, which is consistent with the magnetic flux distribution N(?)??{sup –1.85} observed by Parnell et al. and the heating flux scaling law F{sub H} ?HL?B/L of Schrijver et al.. The fractal-diffusive self-organized criticality model in conjunction with the RTV scaling law reproduces the observed power-law distributions and their slopes for all geometrical and physical parameters and can be used to predict the size distributions for other flare data sets, instruments, and detection algorithms.

  8. Kentucky Law Survey: Family Law

    Microsoft Academic Search

    Louise Everett Graham

    1998-01-01

    This Article addresses some of the family law developments occurring since the Kentucky Law Journal last published a Kentucky law survey. Space limitations preclude discussion of every post-1985 change. Instead, this Article focuses on general trends, significant cases, and legislative developments.\\u000aInquiry into family law developments in Kentucky is timely, not only because of the social importance of family relations,

  9. Darwin's evolutionary philosophy: The laws of change

    Microsoft Academic Search

    Edward S. Reed

    1978-01-01

    The philosophical or metaphysical architecture of Darwin's theory of evolution by natural selection is analyzed and diflussed. It is argued that natural selection was for Darwin a paradigmatic case of a natural law of change — an exemplar of what Ghiselin (1969) has called selective retention laws. These selective retention laws lie at the basis of Darwin's revolutionary world view.

  10. 32 CFR 750.46 - Applicable law.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...manifestation(s) of the emotional distress; and (3) Claims under the MCA do not include the principles of absolute liability and punitive damages. (d) Clarification of terms. Federal law determines the meaning and construction...

  11. Property Evaluation and Damage Evolution of Environmental Barrier Coatings and Environmental Barrier Coated SiC/SiC Ceramic Matrix Composite Sub-Elements

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Halbig, Michael; Jaskowiak, Martha; Hurst, Janet; Bhatt, Ram; Fox, Dennis S.

    2014-01-01

    This paper describes recent development of environmental barrier coatings on SiC/SiC ceramic matrix composites. The creep and fatigue behavior at aggressive long-term high temperature conditions have been evaluated and highlighted. Thermal conductivity and high thermal gradient cyclic durability of environmental barrier coatings have been evaluated. The damage accumulation and complex stress-strain behavior environmental barrier coatings on SiCSiC ceramic matrix composite turbine airfoil subelements during the thermal cyclic and fatigue testing of have been also reported.

  12. Consequences of the Thermal Transient on the Evolution of the Damaged Zone Around a Repository for Heat-Emitting High-Level Radioactive Waste in a Clay Formation: a Performance Assessment Perspective

    NASA Astrophysics Data System (ADS)

    Yu, Li; Weetjens, Eef; Sillen, Xavier; Vietor, Tim; Li, Xiangling; Delage, Pierre; Labiouse, Vincent; Charlier, Robert

    2014-01-01

    A proper evaluation of the perturbations of the host rock induced by the excavation and the emplacement of exothermic wastes is essential for the assessment of the long-term safety of high-level radioactive waste disposals in clay formations. The impact of the thermal transient on the evolution of the damaged zone (DZ) has been explored in the European Commission project TIMODAZ (thermal impact on the damaged zone around a radioactive waste disposal in clay host rocks, 2006-2010). This paper integrates the scientific results of the TIMODAZ project from a performance assessment (PA) point of view, showing how these results support and justify key PA assumptions and the values of PA model parameters. This paper also contextualises the significance of the thermal impact on the DZ from a safety case perspective, highlighting how the project outcomes result into an improved understanding of the thermo-hydro-mechanical behaviour of the clay host rocks. The results obtained in the TIMODAZ project strengthen the assessment basis of the safety evaluation of the current repository designs. There was no evidence throughout the TIMODAZ experimental observations of a temperature-induced additional opening of fractures nor of a significant permeability increase of the DZ. Instead, thermally induced plasticity, swelling and creep seem to be beneficial to the sealing of fractures and to the recovery of a very low permeability in the DZ, close to that of an undisturbed clay host rock. Results from the TIMODAZ project indicate that the favourable properties of the clay host rock, which guarantee the effectiveness of the safety functions of the repository system, are expected to be maintained after the heating-cooling cycle. Hence, the basic assumptions usually made in PA calculations so far are expected to remain valid, and the performance of the system should not be affected in a negative way by the thermal evolution of the DZ around a radioactive waste repository in clay host rock.

  13. A non-local visco-elastic damage model and dynamic fracturing Vladimir Lyakhovsky a,n

    E-print Network

    Lyakhovsky, Vladimir

    online 6 June 2011 Keywords: Fracture Phase transformation Dynamics Constitutive Behavior Damage rheology-term dissipation stabilizing the damage evolution. The third term produces a finite length scale for damage for damage evolution derived from basic thermodynamic considerations quantifies the kinetics of damage under

  14. Employment Law

    NSDL National Science Digital Library

    Runkel, Ross, 1939-

    Ross Runkel is a retired professor of law, and given his long experience with employment and labor law, it seems quite natural that he would be the founder of the site, Employment Law. Along with a team of other equally qualified professionals, he has created this site to serve as a clearinghouse of material about the world of employment law and its many facets. First time visitors may wish to check out his employment law or arbitration blogs, then move on to one of the most popular features, a list of recent and pending cases in the field that have been heard before the US Supreme Court. Additionally, the â??Articlesâ?ť area contains pieces authored by Runkel and others, including a piece on how to find an employment lawyer and several timely pieces on the National Labor Relations Board.

  15. Defect interactions with stepped CeO2/SrTiO3 interfaces: Implications for radiation damage evolution and fast ion conduction

    NASA Astrophysics Data System (ADS)

    Dholabhai, Pratik P.; Aguiar, Jeffery A.; Misra, Amit; Uberuaga, Blas P.

    2014-05-01

    Due to reduced dimensions and increased interfacial content, nanocomposite oxides offer improved functionalities in a wide variety of advanced technological applications, including their potential use as radiation tolerant materials. To better understand the role of interface structures in influencing the radiation damage tolerance of oxides, we have conducted atomistic calculations to elucidate the behavior of radiation-induced point defects (vacancies and interstitials) at interface steps in a model CeO2/SrTiO3 system. We find that atomic-scale steps at the interface have substantial influence on the defect behavior, which ultimately dictate the material performance in hostile irradiation environments. Distinctive steps react dissimilarly to cation and anion defects, effectively becoming biased sinks for different types of defects. Steps also attract cation interstitials, leaving behind an excess of immobile vacancies. Further, defects introduce significant structural and chemical distortions primarily at the steps. These two factors are plausible origins for the enhanced amorphization at steps seen in our recent experiments. The present work indicates that comprehensive examination of the interaction of radiation-induced point defects with the atomic-scale topology and defect structure of heterointerfaces is essential to evaluate the radiation tolerance of nanocomposites. Finally, our results have implications for other applications, such as fast ion conduction.

  16. Florida Law

    NSDL National Science Digital Library

    2011-01-01

    This fine collection from the University of Florida's George A. Smathers Libraries documents the laws and legal heritage of Florida. It has digitized texts from the holdings of the University of Florida's Lawton Chiles Legal Information Center and the P. K. Yonge Library of Florida History as well as other sources. This omnibus collection features the Journal of the Florida House of Representatives, a variety of general texts on Florida laws, and the Florida Water Law collection. This last collection is particularly fascinating as it brings together over 7,000 documents related to long-term water management plans across the Sunshine State. Moving on, the Florida Historical Legal Documents section of the site contains primary source materials that survey changes in Florida law from 1822 through 1845, when the area became a state. Finally, the House Journal section brings together the official record of actions taken by the House and its committees.

  17. Congenital ureteropelvic junction obstruction: physiopathology, decoupling of tout court pelvic dilatation-obstruction semantic connection, biomarkers to predict renal damage evolution.

    PubMed

    Alberti, C

    2012-02-01

    The widespread use of fetal ultrasonography results in a frequent antenatally observation of hydronephrosis, ureteropelvic junction obstruction (UPJO) accounting for the greatest fraction of congenital obstructive nephropathy. UPJO may be considered, in most cases, as a functional obstructive condition, depending on defective fetal smooth muscle/nerve development at this level, with lack of peristaltic wave propagation--aperistaltic segment--and, therefore, poor urine ejection from the renal pelvis into the ureter. The UPJO-related physiopathologic events are, at first, the compliant dilatation of renal pelvis that, acting as hydraulic buffer, protects the renal parenchyma from the rising intrapelvic pressure-related potential damages, and, subsequently, beyond such phase of dynamic balance, the tubular cell stretch-stress induced by increased intratubular pressure and following parenchymal inflammatory lesions: inflammatory infiltrates, fibroblast proliferation, activation of myofibroblasts, tubulo-interstitial fibrosis. Reactive oxygen species (ROS), nitric oxide (NO), several chemo- and cytokines, growth factors, prostaglandins and eicosanoids, angiotensin-II are the main pathogenetic mediators of the obstructive nephropathy. Apoptosis of tubular cells is the major cause of the tubular atrophy, together with epithelial-mesenchymal transdifferentiation. Some criticisms on tout court semantic renal pelvis dilatation-obstruction connection have been raised considering that the renal pelvis expansion isn't, in any case, linked to an ostructive condition, as it may be verified by diuretic (furosemide) renogram together with scintiscan-based evaluation of differential renal function. In this regard, rather than repetitive invasive nuclear procedures that expose the children to ionizing radiations, an intriguing noninvasive strategy, based on the evaluation of urinary biomarkers and urinary proteome, can define the UPJO-related possible progress of parenchymal lesions, thus predicting which patients must require an obstruction correcting surgery and in which patients, instead, the hydronephrosis will spontaneously resolve. PMID:22428472

  18. MULTI-WAVELENGTH OBSERVATIONS OF THE SPATIO-TEMPORAL EVOLUTION OF SOLAR FLARES WITH AIA/SDO. I. UNIVERSAL SCALING LAWS OF SPACE AND TIME PARAMETERS

    SciTech Connect

    Aschwanden, Markus J. [Lockheed Martin Advanced Technology Center, Org. ADBS, Bldg. 252, 3251 Hanover St., Palo Alto, CA 94304 (United States); Zhang, Jie; Liu, Kai, E-mail: aschwanden@lmsal.com, E-mail: jzhang7@gmu.edu [School of Physics, Astronomy and Computational Sciences, George Mason University, 4400 University Dr., MSN 6A2, Fairfax, VA 22030 (United States)

    2013-09-20

    We extend a previous statistical solar flare study of 155 GOES M- and X-class flares observed with AIA/SDO to all seven coronal wavelengths (94, 131, 171, 193, 211, 304, and 335 Ĺ) to test the wavelength dependence of scaling laws and statistical distributions. Except for the 171 and 193 Ĺ wavelengths, which are affected by EUV dimming caused by coronal mass ejections (CMEs), we find near-identical size distributions of geometric (lengths L, flare areas A, volumes V, and fractal dimension D{sub 2}), temporal (flare durations T), and spatio-temporal parameters (diffusion coefficient ?, spreading exponent ?, and maximum expansion velocities v{sub max}) in different wavelengths, which are consistent with the universal predictions of the fractal-diffusive avalanche model of a slowly driven, self-organized criticality (FD-SOC) system, i.e., N(L)?L {sup –3}, N(A)?A {sup –2}, N(V)?V {sup –5/3}, N(T)?T {sup –2}, and D{sub 2} = 3/2, for a Euclidean dimension d = 3. Empirically, we find also a new strong correlation ??L {sup 0.94±0.01} and the three-parameter scaling law L?? T {sup 0.1}, which is more consistent with the logistic-growth model than with classical diffusion. The findings suggest long-range correlation lengths in the FD-SOC system that operate in the vicinity of a critical state, which could be used for predictions of individual extreme events. We find also that eruptive flares (with accompanying CMEs) have larger volumes V, longer flare durations T, higher EUV and soft X-ray fluxes, and somewhat larger diffusion coefficients ? than confined flares (without CMEs)

  19. Molecular dynamics simulation of radiation damage cascades in diamond

    NASA Astrophysics Data System (ADS)

    Buchan, J. T.; Robinson, M.; Christie, H. J.; Roach, D. L.; Ross, D. K.; Marks, N. A.

    2015-06-01

    Radiation damage cascades in diamond are studied by molecular dynamics simulations employing the Environment Dependent Interaction Potential for carbon. Primary knock-on atom (PKA) energies up to 2.5 keV are considered and a uniformly distributed set of 25 initial PKA directions provide robust statistics. The simulations reveal the atomistic origins of radiation-resistance in diamond and provide a comprehensive computational analysis of cascade evolution and dynamics. As for the case of graphite, the atomic trajectories are found to have a fractal-like character, thermal spikes are absent and only isolated point defects are generated. Quantitative analysis shows that the instantaneous maximum kinetic energy decays exponentially with time, and that the timescale of the ballistic phase has a power-law dependence on PKA energy. Defect recombination is efficient and independent of PKA energy, with only 50% of displacements resulting in defects, superior to graphite where the same quantity is nearly 75%.

  20. Undermining Evolution: Where State Standards Go Wrong

    ERIC Educational Resources Information Center

    American Educator, 2012

    2012-01-01

    While many states are handling evolution better today than in the past, anti-evolution pressures continue to threaten state science standards. In April 2012, for example, Tennessee passed a law that enables teachers to bring anti-evolution materials into the classroom without being challenged by administrators. This law is similar to the Science…

  1. Multi-Wavelength Observations of the Spatio-Temporal Evolution of Solar Flares with AIA/SDO: I. Universal Scaling Laws of Space and Time Parameters

    E-print Network

    Aschwanden, Markus J; Liu, Kai

    2013-01-01

    We extend a previous statistical solar flare study of 155 GOES M- and X-class flares observed with AIA/SDO (Aschwanden 2012) to all 7 coronal wavelengths (94, 131, 171, 193, 211, 304, 335 \\ang) to test the wavelength-dependence of scaling laws and statistical distributions. Except for the 171 and 193 \\ang\\ wavelengths, which are affected by EUV dimming caused by coronal mass ejections (CMEs), we find near-identical size distributions of geometric (lengths $L$, flare areas $A$, volumes $V$, fractal dimension $D_2$), temporal (flare durations $T$), and spatio-temporal parameters (diffusion coefficient $\\kappa$, spreading exponent $\\beta$, and maximum expansion velocities $v_{max}$) in different wavelengths, which are consistent with the universal predictions of the fractal-diffusive avalanche model of a slowly-driven self-organized criticality (FD-SOC) system, i.e., $N(L) \\propto L^{-3}$, $N(A) \\propto A^{-2}$, $N(V) \\propto V^{-5/3}$, $N(T) \\propto T^{-2}$, $D_2=3/2$, for a Euclidean dimension $d=3$. Empirical...

  2. SIMULATION OF PROGRESSIVE DAMAGE IN BOLTED COMPOSITE JOINTS

    Microsoft Academic Search

    Hannes Koerber; Pedro P. Camanho

    Recently, a continuum based progressive damage model for fiber-reinforced composites became available in the commercial finite element code ABAQUS. The implemented model uses the Hashin damage initiation criteria (1,2) and damage evolution is based on the work of Matzenmiller (3) and Camanho and Davila (4). The \\

  3. Damage and fracture simulation during the extrusion processes

    Microsoft Academic Search

    Ridha Hambli; Daniel Badie-Levet

    2000-01-01

    In order to accurately predict the damage and failure evolution in the case of metal forming processes, such as stamping and extrusion, a finite element model valid for numerically describing of such processes has been developed. Damage and crack propagation have been taken into account by means of continuum damage mechanics concepts. To study the effects of variation of processes

  4. Public Interest Law: Five Years Later.

    ERIC Educational Resources Information Center

    Jaffe, Sanford

    This report provides an account of public-interest law firm activities supported by the Ford Foundation. Public interest law is a phrase that describes efforts aimed at providing legal representation for underrepresented interests in the legal process. The report is arranged into four major sections. The first section, on the evolution of the…

  5. 26 CFR 1.186-1 - Recoveries of damages for antitrust violations, etc.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Recoveries of damages for antitrust violations, etc. 1.186-1 Section...186-1 Recoveries of damages for antitrust violations, etc. (a) Allowance... (4) Injury suffered under certain antitrust law violations. An injury...

  6. School Law

    ERIC Educational Resources Information Center

    Splitt, David A.

    1987-01-01

    Forecasts no major surprises during the U.S. Supreme Court's 1987-88 term. Like the "Edwards v. Aguillard" ruling against Louisiana's creation science law, upcoming decisions concerning religious issues (controversial textbooks and moments of silence) and free speech (language use and controversial subject matter in student publications) will…

  7. Faraday's Law

    NSDL National Science Digital Library

    Light a light bulb by waving a magnet. This simulation of a Faraday's Law is from the Physics Education Technology website of University of Colorado. It is accessible for teachers and students alike. Included are links to related topics and additional ideas and activities for teachers to use.

  8. School Law.

    ERIC Educational Resources Information Center

    Splitt, David A.

    1982-01-01

    Summarizes three current issues in school law, including school district suits over potentially carcinogenic asbestos insulation, a California judge's finding that captionless educational television discriminates against hearing-impaired students, and the federal government's attempt to keep the Fairfax (Virginia) school system from charging…

  9. School Law.

    ERIC Educational Resources Information Center

    Splitt, David A.

    1985-01-01

    Discusses (1) a Michigan court decision concerning reverse discrimination and voluntary affirmative action policies; (2) the Massachusetts Supreme Court's rejection of the work-to-rule strategy; and (3) an Arkansas law that will allow teachers failing a basic skills and literacy test to be fired only when their state certification expires. (MLF)

  10. Fractional order viscoelasticity and theoretical progress in rheological constitutive law for rocks

    NASA Astrophysics Data System (ADS)

    Kawada, Y.; Yajima, T.; Nagahama, H.

    2010-12-01

    Fractional calculus has recently become an important tool in the analysis of relaxation phenomena, such as stress-strain relationships in composite materials. This is because the memory effect, an essence of viscoelasticity, cannot be entirely described by the empirical constitutive equations with the integer-order time derivative. We derive a generalized viscoelastic constitutive equation from an energy function with fractional-order time derivatives. The constitutive equation reduces the empirical models of viscoelasticity such as Maxwell, Kelvin-Voigt and Zener models and represents the relaxation behavior of any kind of viscoelastic materials such as polymer, metal and rocks, enabling us to investigate the time-dependent property of relaxation and the origin of power-law dynamics. The constitutive equation is a differential equation with fractional order, and taking the Laplace transformations yield solutions with the Mittag-Leffler function having the asymptotic behavior of temporal power-law. The constitutive equation is hence equivalent to the Boltzmann superposition integral (a definition of the viscoelastic behavior) with power-law kernel, i.e., the Green’s function exhibiting temporal power-law relaxation, and in its special case, the kernel becomes an exponential function having a characteristic time. We also analyze experimental data sets on the deformation of rocks such as halite and lherzolite exhibiting the empirical flow-law (the power-law scaling between bulk stress and strain-rate) and show that the behaviors can be described by the viscoelastic constitutive equation with fractional-order derivatives as well. The order of fractional derivative is identical to the reciprocal of stress exponent of flow law reflecting the memory effect in viscoelasticity and the deformation mechanisms of rocks. It is also denoted that the power-law scaling in viscoelastic behavior of rocks is related to aspects of crustal fluid dynamics and change in atmospheric radon concentration associated with damage evolution prior to catastrophic failure (analogous to an earthquake).

  11. On the description of anisotropic damage in composite laminates

    NASA Astrophysics Data System (ADS)

    Wei, Yang; Boehler, J. P.

    1991-11-01

    A general anisotropic damage theory of cracked laminates is formulated here. The deformation of composite laminates is composed of matrix elastic strains, pseudo-elastic damage strains due to cracking and permanent damage strains due to interlaminar slip. The surface of damage initiation is constructed according to the concept of linear elastic fracture mechanics for the virgin material. After the initial damage, a pesudo-elastic damage can be used to describe the damage behaviour if interlaminar slip is negligible. Damage evolution, load induced anisotropy and interlaminar intralaminar interaction for composite laminates are examined; the latter can perturb the normality structure of damage strain rate. Explicit expressions are given for pseudo-elastic (or secant) moduli of the damaging composite laminates, under a non-interacting assumption imposed on the cracks between different families.

  12. Evolution Noonan Evolution 301

    E-print Network

    Goulet, Denis C.

    Evolution Noonan Spring 08 Evolution 301 Instructor: Brice Noonan Office: 504 Shoemaker e-mail: bnoonan@olemiss.edu Class time: T,Th: 8:00 ­ 9:15 Office Hrs: T, Th: 9:15 ­ 10:45 Text: Evolution (Futuyma Week 3: Jan 29, 21 Chapter 3: Patterns of Evolution Week 4: Feb 5, 7 Chapter 4,5: Evolution

  13. Ampere's Law

    NSDL National Science Digital Library

    2014-09-18

    The lesson begins with a demonstration introducing students to the force between two current carrying loops, comparing the attraction and repulsion between the loops to that between two magnets. After formal lecture on Ampere's law, students begin to use the concepts to calculate the magnetic field around a loop. This is applied to determine the magnetic field of a toroid, imagining a toroid as a looped solenoid.

  14. Damage and fatigue described by a fractional derivative model

    NASA Astrophysics Data System (ADS)

    Caputo, Michele; Fabrizio, Mauro

    2015-07-01

    As in [1], damage is associated with fatigue that a material undergoes. In this paper, because we work with viscoelastic solids represented by a fractional model, damage is described by the order of the fractional derivative, which represents the phase field satisfying Ginzburg-Landau equation, which describes the evolution of damage. Finally, in our model, damage is caused, not only by fatigue, but also directly by a source related to environmental factors and described by a positive time function.

  15. Nonlocal Damage Gradient Model for Fracture Characterization of Aluminum Alloy

    Microsoft Academic Search

    Chi L. Chow; Jianghui Mao; Jie Shen

    2011-01-01

    This article presents the development of a generalized nonlocal damage-coupled material model. The model introduces the concept of cumulative damage gradient through a set of damage evolution equations within the irreversible thermodynamics framework. The conventional damage-coupled plasticity models require either self-developed finite element codes or the mandatory use of regular elements. The proposed material model is implemented in a commercial

  16. 48 CFR 1422.302 - Liquidated damages and overtime pay.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...DEPARTMENT OF THE INTERIOR SOCIOECONOMIC PROGRAMS APPLICATION OF LABOR LAWS TO GOVERNMENT ACQUISITIONS Contract Work Hours and Safety Standards Act 1422.302 Liquidated damages and overtime pay. (a) HCAs are authorized to take the...

  17. 48 CFR 222.302 - Liquidated damages and overtime pay.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...LABOR LAWS TO GOVERNMENT ACQUISITIONS Contract Work Hours and Safety Standards Act 222.302 Liquidated damages and...pay. Upon receipt of notification of Contract Work Hours and Safety Standards Act violations, the contracting...

  18. 48 CFR 222.302 - Liquidated damages and overtime pay.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...LABOR LAWS TO GOVERNMENT ACQUISITIONS Contract Work Hours and Safety Standards Act 222.302 Liquidated damages and...pay. Upon receipt of notification of Contract Work Hours and Safety Standards Act violations, the contracting...

  19. 48 CFR 1422.302 - Liquidated damages and overtime pay.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...DEPARTMENT OF THE INTERIOR SOCIOECONOMIC PROGRAMS APPLICATION OF LABOR LAWS TO GOVERNMENT ACQUISITIONS Contract Work Hours and Safety Standards Act 1422.302 Liquidated damages and overtime pay. (a) HCAs are authorized to take the...

  20. STOCHASTIC MODELING OF HURRICANE DAMAGE: REANALYSIS OF UPDATED DATA

    E-print Network

    Katz, Richard

    " · Number of Events ("Law of Small Numbers") -- Poisson distribution (Trend? Other covariates?) · Damage from Individual Storms -- Lognormal distribution (Trend? Other covariates?) -- Generalized Pareto (GP" Y = X - u over high threshold u Model Y with Generalized Pareto (GP) distribution Distribution

  1. Creep damage and expected creep life for welded 9–11% Cr steels

    Microsoft Academic Search

    P. Auerkari; S. Holmström; J. Veivo; J. Salonen

    2007-01-01

    The damage mechanisms affecting engineering steels at high-temperatures include creep cavitation and cracking that can form the path for final failure in susceptible locations such as welds. The evolution of observed damage is widely used in condition monitoring, timing of inspections and support of life management. However, the damage evolution is material dependent, and requires confirmation from inspection data. For

  2. Damaged Skylab

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The Saturn V vehicle, carrying the unmarned orbital workshop for the Skylab-1 mission, lifted off successfully and all systems performed normally. Sixty-three seconds into the flight, engineers in the operation support and control center saw an unexpected telemetry indication that signalled that damages occurred on one solar array and the micrometeoroid shield during the launch. The micrometeoroid shield, a thin protective cylinder surrounding the workshop, that protected it from tiny space particles and the sun's scorching heat, ripped loose from its position around the workshop. This caused the loss of one solar wing and jammed the other. Still unoccupied, the Skylab was stricken with the loss of the heat shield and sunlight beat mercilessly on the lab's sensitive skin. Internal temperatures soared, rendering the station uninhabitable, threatening foods, medicines, films, and experiments. This image, taken during a fly-around inspection by the Skylab-2 crew, shows the exterior skin of the workshop discolored by solar radiation. The Marshall Space Flight Center (MSFC) developed, tested, rehearsed, and approved three repair options. These options included a parasol sunshade and a twin-pole sunshade to restore the temperature inside the workshop, and a set of metal cutting tools to free the jammed solar panel.

  3. Scaling of fracture length and distributed damage

    NASA Astrophysics Data System (ADS)

    Lyakhovsky, Vladimir

    2001-01-01

    The linear theory of elasticity formulated in terms of dimensionless strain components does not allow the introduction of any space scaling except linear relations between fracture length and displacements and thus the determination theoretically of the strength of a body or structure directly. Self-similarity of a fracture process means the existence of a universal faulting mechanism. However, the general applicability of universal scaling to field observations and rock mechanics measurements remains the subject of some debate. Complete self-similarity of a fracture process is hardly ever found experimentally, except in some aluminium alloys. At early stages of the loading, material degrades due to increasing microcrack concentrations. Later, these microcracks where distributed in the process zone localize into a subcritically growing macrocrack, and finally the fracture process accelerates and rupture runs away, producing dynamic fracture. The macroscopic effects of distributed cracking and other types of damage require treatment by constitutive models that include non-linear stress-strain relations together with material degradation and recovery. The present model treats two physical aspects of the brittle rock behaviour: (1) a mechanical aspect, that is, the sensitivity of the macroscopic elastic moduli to distributed cracks and to the type of loading, and (2) a kinetic aspect, that is, damage evolution (degradation/recovery of elasticity) in response to ongoing deformation. To analyse the scaling of a fracture process and the onset of the dynamic events, we present here the results of numerical modelling of mode I crack growth. It is shown that the distributed damage and the process zone created eliminate the stress-strain crack-tip singularities, providing a finite rate of quasi-static crack growth. The growth rate of these cracks fits well the experimentally observed power law, with the subcritical crack index depending on the ratio between the driving force and the confining pressure. The geometry of the process zone around a quasi-static crack has a self-similar shape identical to that predicted by universal scaling of the linear fracture mechanics. At a certain stage, controlled by dynamic weakening and approximated by the reduction of the critical damage level proportional to the rate of a damage increase, the self-similarity breaks down and crack velocity significantly deviates from that predicted by the quasi-static regime. The subcritical crack growth index increases steeply, crack growth accelerates, the size of the process zone decreases, and the rate of crack growth ceases to be controlled by the rate of damage increase. Furthermore, the crack speed approaches that predicted by the elastodynamic equation. The model presented describes transition from quasi-static crack propagation to the dynamic regime and gives proper time and length scales for the onset of the catastrophic dynamic process.

  4. Newton's Laws

    NSDL National Science Digital Library

    Willey, David

    This page consists of a lists of activities relating to Newton's Laws. Created by David Willey at the University of Pittsburgh, these activities include a bowling ball pendulum, human air puck, a table cloth and crockery, a sewing hoop, an egg and a sheet and bicycle wheel gyroscope. This is a nice set on interactive lesson plans for physics instructors. Willey provides a brief description of each. Additional links are provided to more interactive lessons for those interested in physics. Instructors should be able to implement many of these ideas into their curriculum.

  5. State Highway Safety Laws

    MedlinePLUS

    State Highway Safety Laws & Funding State Laws Each state and U.S. territory has enacted laws governing various driver behaviors, ... page contains charts for a specific type of highway safety law, listing the provisions for all U.S. ...

  6. An anisotropic model of damage for brittle materials with different behavior in tension and compression

    Microsoft Academic Search

    A. Zolochevsky; E. Yeseleva; W. Ehlers

    2005-01-01

    The article outlines a continuum damage mechanics model for elastic deformation associated with the appearance and growth of parallel penny-shaped microcracks in brittle materials. The model is able to describe simultaneously the anisotropic nature of damage and the difference between the damaging processes under tensile and compressive loading types. Constitutive equation and damage evolution equations are developed on the basis

  7. Plant evolution The Evolution

    E-print Network

    Rieseberg, Loren

    Plant evolution The Evolution of Plants by Kathy J. Willis and Jenny C. McElwain. Oxford University Press, 2002. $40.00/Ł22.99 pbk (378 pages) ISBN 0 19 850065 3 Developmental Genetics and Plant Evolution is observed for treatments of evolution and development. Titles of major monographs on the subject imply

  8. Administrative Law: The Hidden Comparative Law Course.

    ERIC Educational Resources Information Center

    Strauss, Peter L.

    1996-01-01

    Argues that the main contribution of the Administrative Law course to law students is that it presents problems which contrast with those of the standard court-centered curriculum and can illuminate other areas of law, repeatedly confronting students with doctrinal differences. Offers several examples from civil procedure, constitutional law, and…

  9. Entropic Corrections to Coulomb's Law

    E-print Network

    S. H. Hendi; A. Sheykhi

    2011-10-17

    Two well-known quantum corrections to the area law have been introduced in the literatures, namely, logarithmic and power-law corrections. Logarithmic corrections, arises from loop quantum gravity due to thermal equilibrium fluctuations and quantum fluctuations, while, power-law correction appears in dealing with the entanglement of quantum fields in and out the horizon. Inspired by Verlinde's argument on the entropic force, and assuming the quantum corrected relation for the entropy, we propose the entropic origin for the Coulomb's law in this note. Also we investigate the Uehling potential as a radiative correction to Coulomb potential in 1-loop order and show that for some value of distance the entropic corrections of the Coulomb's law is compatible with the vacuum-polarization correction in QED. So, we derive modified Coulomb's law as well as the entropy corrected Poisson's equation which governing the evolution of the scalar potential $\\phi$. Our study further supports the unification of gravity and electromagnetic interactions based on the holographic principle.

  10. The Second Law of Thermodynamics

    NSDL National Science Digital Library

    The Second Law of Thermodynamics can be stated as: Energy spontaneously tends to flow from being concentrated in one place to becoming diffused and spread out - or - disorder in a closed system will increase. This radio broadcast explains this law, its implications as to time and energy in the universe, and whether the Second Law tends to be refuted by the existence of life and the theory of evolution. The broadcast explains how the Sun-Earth system is like a steam engine where the Sun is the hot engine, the Earth is a cold sink, and the biosphere plays the part of the pistons by converting energy from the Sun into work needed to provide for life on Earth. There is discussion about the relation between the Second Law and the Big Bang, the expansion of the cosmos, and our inexorable passage through time towards the heat death of the universe; how gravity stores negative energy, which enables it to create order out of disorder; and why the Second Law may be the most fundamental law in all of science. The broadcast is 43 minutes in length.

  11. Prolegomenon to patterns in evolution.

    PubMed

    Kauffman, Stuart A

    2014-09-01

    Despite Darwin, we remain children of Newton and dream of a grand theory that is epistemologically complete and would allow prediction of the evolution of the biosphere. The main purpose of this article is to show that this dream is false, and bears on studying patterns of evolution. To do so, I must justify the use of the word "function" in biology, when physics has only happenings. The concept of "function" lifts biology irreducibly above physics, for as we shall see, we cannot prestate the ever new biological functions that arise and constitute the very phase space of evolution. Hence, we cannot mathematize the detailed becoming of the biosphere, nor write differential equations for functional variables we do not know ahead of time, nor integrate those equations, so no laws "entail" evolution. The dream of a grand theory fails. In place of entailing laws, I propose a post-entailing law explanatory framework in which Actuals arise in evolution that constitute new boundary conditions that are enabling constraints that create new, typically unprestatable, adjacent possible opportunities for further evolution, in which new Actuals arise, in a persistent becoming. Evolution flows into a typically unprestatable succession of adjacent possibles. Given the concept of function, the concept of functional closure of an organism making a living in its world becomes central. Implications for patterns in evolution include historical reconstruction, and statistical laws such as the distribution of extinction events, or species per genus, and the use of formal cause, not efficient cause, laws. PMID:24704211

  12. Evolution, Fundamentalism, and American Education.

    ERIC Educational Resources Information Center

    Doyle, James J.

    1988-01-01

    Describes four court cases involving confrontation between the theory of evolution and the theory of creation: the Scopes trial, the Seagraves trial, Arkansas Act 590, and the Louisiana law. Provides 64 references on the issue. (YP)

  13. Damage analysis and fundamental studies. Quarterly progress report, October-December 1979

    SciTech Connect

    Doran, D. G.

    1980-02-01

    Progress on each of the following topics is outlined: (1) rotating target neutron source, (2) fusion materials irradiation test facility, (3) environmental characterization, (4) damage production, and (5) damage microstructure evolution and mechanical behavior. (MOW)

  14. The Fourth Law of Thermodynamics

    Microsoft Academic Search

    R. e. Morel; George Fleck

    1972-01-01

    Abstract. Classical thermodynamics, based on conservation of matter and en- ergy and on the increase of entropy accompanying every natural event, reliably predicts equilibrium properties of macroscopic systems, regardless of the complex- ity of those systems. Thermodynamic,theory historically has had little to say about the far-from-equilibrium evolution of systems. This is in part because the classical laws of thermodynamics, limited

  15. Educational Malpractice and Special Education Law.

    ERIC Educational Resources Information Center

    Coultas, Faye M.

    1979-01-01

    Handicapped students have safeguards that go beyond those for other students and these safeguards may provide the basis for a personal damage action or an educational malpractice suit by a handicapped child or his or her parent. Available from IIT/Chicago-Kent College of Law, 77 South Wacker Drive, Chicago, IL 60606; single copies $5.00.…

  16. Evolution towards Symmetry Ferdinand Verhulst and Richard Huveneers

    E-print Network

    Verhulst, Ferdinand

    Evolution towards Symmetry Ferdinand Verhulst and Richard Huveneers Mathematisch Instituut those of today and will the laws of tomorrow still be the same? Henri Poincar´e in `The evolution of the laws', Derni`eres Pens´ees. Abstract The dynamics of time-dependent evolution towards symmetry

  17. The relationship between stress, porosity, and nonlinear damage accumulation in acrylic bone cement

    Microsoft Academic Search

    B. P. Murphy; P. J. Prendergast

    2002-01-01

    The long-term survival of cemented hip replace- ments depends on the ability of the cemented fixation to resist fatigue damage. Damage has been assumed to accu- mulate linearly (Miner's law) even though it is unlikely to be the case in such a porous brittle material. This study ad- dresses the nonlinear stress-dependent nature of fatigue damage accumulation in acrylic bone

  18. Damage Detection in Composite Plates by Using an Enhanced Time Reversal Method

    E-print Network

    Kim, Yong Jung

    Damage Detection in Composite Plates by Using an Enhanced Time Reversal Method Hoon Sohn1 ; Hyun Woo Park2 ; Kincho H. Law3 ; and Charles R. Farrar4 Abstract: A damage detection technique, which does not rely on any past baseline signals, is proposed to assess damage in composite plates by using

  19. Evolution and Friendship

    ERIC Educational Resources Information Center

    Mena-Werth, Jose

    2005-01-01

    In 1925, Williams Jennings Bryan, a former congressman from Nebraska and a former Secretary of State under Woodrow Wilson, spent two agonizing weeks defending his religious faith that cost him his life a month after. Bryan was a prosecutor of high school teacher John Scopes, who had violated Tennessee state law by teaching the theory of evolution.…

  20. Sobriety Checkpoint Laws

    MedlinePLUS

    Sobriety Checkpoint Laws Sobriety checkpoints (also called DUI checkpoints) are locations where law enforcment officers are stationed to check drivers for ... all states conduct sobriety checkpoints. Some states have laws authorizing their use. Others forbid them or are ...

  1. Customary Law in Common Law Systems

    Microsoft Academic Search

    Gordon R. Woodman

    2001-01-01

    Drawing on the experience of the operation of customary law accumulated in common law colonial and post-colonial African countries, I seek to contribute to answers to two questions. The first concerns the significance of the rule of law in development; my tentative answer will be that it is indeed significant, but not at all in the manner or for the

  2. Damage analysis during hot deformation of a resulfurised stainless steel

    Microsoft Academic Search

    H. Tinet; H. Klöcker; J. Le Coze

    2004-01-01

    Ductile damage evolution and fracture of a resulfurised stainless steel (AISI 303) were analysed by high temperature tension tests. Void nucleation, growth and coalescence were investigated. The existence of two distinct void coalescence mechanisms has been demonstrated. High temperature damage models assume the existence of a critical value of the void volume fraction at the onset of void coalescence. In

  3. DDSIM: A NEXT GENERATION DAMAGE AND DURABILITY SIMULATOR

    Microsoft Academic Search

    JOHN M. EMERY; PAUL A. WAWRZYNEK; ANTHONY R. INGRAFFEA

    Current state-of-practice tools for life prediction of structural components are limited in some or all of the following capabilities: geometry of and boundary conditions on the affected structural component, automation of the analysis process, stochastics of the primary variables, and physics of the damage evolution processes. A next generation damage and durability simulator, DDSim, is being developed to address each

  4. Friction-damage coupled model for brittle materials

    Microsoft Academic Search

    Luigi Gambarotta

    2004-01-01

    By considering a tensorial description of the damage and of the unilateral and frictional effects on the displacement jump across the crack faces, an anisotropic constitutive model based on the assumption of linear elastic matrix weakened by microcraks is derived. Damage and sliding evolutions are obtained on the basis of proper limit conditions and associated flow rules. This treatment implies

  5. The story of abortion law in Poland.

    PubMed

    Chazan, B

    1996-12-01

    Poland's 1956 abortion law permitted abortion on demand without state control or reporting mechanisms. It has been estimated that this liberal law resulted in as many as 400,000 abortions in 1962 alone. After the Communist regime ended, a new law was passed in March 1993 to provide legal protection to "conceived children." This law allowed abortion only when the pregnancy constitutes a threat to the life or a serious threat to the health of the mother, the fetus is irreversibly damaged, or the pregnancy resulted from rape or incest. Opponents of this law predicted it would result in prosecution of a huge number of women and that it would have an adverse effect on maternal mortality rates. However, there have been only a few court cases to date, and maternal mortality is decreasing. The discussion surrounding this new law has resulted in growing awareness that the fetus is a human being rather than a mass of tissue. Interest in modern contraceptive methods is also increasing. Public opinion polls indicate that most Poles approve of abortions only in the cases indicated by the law and that only 42% of respondents also support availability of abortion for social reasons. However, a law passed in October 1996 will allow women to request abortions for social reasons after counseling and a waiting period. PMID:12222282

  6. Plate tectonics, damage and inheritance.

    PubMed

    Bercovici, David; Ricard, Yanick

    2014-04-24

    The initiation of plate tectonics on Earth is a critical event in our planet's history. The time lag between the first proto-subduction (about 4?billion years ago) and global tectonics (approximately 3?billion years ago) suggests that plates and plate boundaries became widespread over a period of 1?billion years. The reason for this time lag is unknown but fundamental to understanding the origin of plate tectonics. Here we suggest that when sufficient lithospheric damage (which promotes shear localization and long-lived weak zones) combines with transient mantle flow and migrating proto-subduction, it leads to the accumulation of weak plate boundaries and eventually to fully formed tectonic plates driven by subduction alone. We simulate this process using a grain evolution and damage mechanism with a composite rheology (which is compatible with field and laboratory observations of polycrystalline rocks), coupled to an idealized model of pressure-driven lithospheric flow in which a low-pressure zone is equivalent to the suction of convective downwellings. In the simplest case, for Earth-like conditions, a few successive rotations of the driving pressure field yield relic damaged weak zones that are inherited by the lithospheric flow to form a nearly perfect plate, with passive spreading and strike-slip margins that persist and localize further, even though flow is driven only by subduction. But for hotter surface conditions, such as those on Venus, accumulation and inheritance of damage is negligible; hence only subduction zones survive and plate tectonics does not spread, which corresponds to observations. After plates have developed, continued changes in driving forces, combined with inherited damage and weak zones, promote increased tectonic complexity, such as oblique subduction, strike-slip boundaries that are subparallel to plate motion, and spalling of minor plates. PMID:24717430

  7. A comparison study between scalar and multi-plane microcracking ceramic damage models

    SciTech Connect

    Grove, D. J.; Rajendran, A. M. [Weapons and Materials Research Directorate, Army Research Laboratory, Aberdeen Proving Ground, Maryland 21005 (United States)

    1998-07-10

    The Rajendran-Grove (RG) ceramic damage model is based on an elastic-plastic-cracking description. A crack density parameter {gamma}(=N{sub o}*a{sup 3}) describes the scalar damage. The number of flaws N{sub o}* is assumed to be constant and the crack size parameter 'a' evolves according to a strain energy release based evolution law. Crack orientation is not considered in this model. However, Espinosa's multi-plane (MP) microcracking model considers crack orientations in nine pre-selected directions and computes damage by summing up the crack density contribution from all nine directions. Both models account for crack opening and sliding. These two models have been implemented in the 1995 version of the EPIC code. We simulated plate impact experiments in which a thin alumina flyer plate impacted a thick alumina plate. The experimental data consisted of particle velocities recorded at the back face of the target plate. This paper compares the results from the EPIC code simulations using the RG and MP ceramic models.

  8. Hyperbolic evolution system for numerical relativity

    SciTech Connect

    Bona, C.; Masso, J. (Departament de Fisica, Universitat de les Illes Balears, E-07071 Palma de Mallorca (Spain))

    1992-02-24

    Einstein evolution equations are written as a hyperbolic system of balance laws. A harmonic time coordinate is used with zero shift vector (harmonic slicing). The principal part of the evolution system reduces to a set of uncoupled wave equations in first order form. The relevance for three-dimensional numerical relativity of both the harmonic slicing and the resulting evolution system is stressed.

  9. SECOND LAW OF THERMODYNAMICS

    E-print Network

    Kostic, Milivoje M.

    SECOND LAW OF THERMODYNAMICS: STATUS AND CHALLENGES San Diego, California, USA 14 ­ 15 June 2011, Second Law of Thermodynamics. PACS: 05.90.+m Second Law of Thermodynamics: Status and Challenges AIP Conf;Revisiting The Second Law of Energy Degradation and Entropy Generation: From Sadi Carnot's Ingenious

  10. Law Related Education Curriculum.

    ERIC Educational Resources Information Center

    Carey, John J.

    Law related education learning modules and lesson plans are presented in this curriculum guide, which is designed to meet three broad goals: (1) to encourage good citizenship and respect for the law by teaching students how to effectively function within the law and to demonstrate and value lawful conduct; (2) to promote a better understanding for…

  11. Community dynamics in an online law journal

    Microsoft Academic Search

    Aldo de Moor; Sjef van Erp

    2004-01-01

    Online communities are continuously evolving socio-technical systems. To provide them with better change management support, a systematic analysis of the norms that govern their evolution is required. In this paper, we present an approach that was used to analyze the community dynamics in an online law journal. Electronic journals in the legal domain are essential instruments in the validation and

  12. Numerical Modeling of Fatigue Damage and Fissure Propagation under Cyclic Loadings

    Microsoft Academic Search

    F. Bogard; P. Lestriez; Y. Q. Guo

    2008-01-01

    The purpose of this work is to develop a numerical simulation procedure in order to predict the evolution of the fatigue damage and rupture in mechanical parts (such as rolling bearings and gears) under cyclic loadings. The study of the fatigue damage evolution, from the first defect appearance until the part's failure, is primordial in view of the preventive maintenance.

  13. Generalized Second Law of Thermodynamics in Warped Dgp Braneworld

    Microsoft Academic Search

    Ahmad Sheykhi; Bin Wang

    2010-01-01

    We investigate the validity of the generalized second law of thermodynamics on the (n - 1)-dimensional brane embedded in the (n + 1)-dimensional bulk. We examine the evolution of the apparent horizon entropy extracted through relation between gravitational equation and the first law of thermodynamics together with the matter field entropy inside the apparent horizon. We find that the apparent

  14. Does Your Collective Bargaining Agreement Violate Antitrust Law?

    ERIC Educational Resources Information Center

    Bigoness, William J.; And Others

    1981-01-01

    To familiarize managers with the conditions under which collective bargaining agreements may violate antitrust law, the historical evolution of antitrust law concerning labor-management relations is traced; the managerial implications of the United States Supreme Court's decisions are discussed; and likely future trends are suggested. (Author/MLF)

  15. The generalized second law of thermodynamics in generalized gravity theories

    Microsoft Academic Search

    Shao-Feng Wu; Bin Wang; Guo-Hong Yang; Peng-Ming Zhang

    2008-01-01

    We investigate the generalized second law of thermodynamics (GSL) in generalized theories of gravity. We examine the total entropy evolution with time including the horizon entropy, the non-equilibrium entropy production, and the entropy of all matter, field and energy components. We derive a universal condition to protect the generalized second law and study its validity in different gravity theories. In

  16. Integrated Modelling of Damage and Fracture in Sheet Metal Forming

    SciTech Connect

    Peerlings, R. H. J.; Geers, M. G. D. [Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven (Netherlands); Mediavilla, J. [Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven (Netherlands); Netherlands Institute for Metals Research, Delft (Netherlands)

    2007-05-17

    A framework for finite element simulations of ductile damage development and ductile fracture during metal forming is presented. The damage evolution is described by a phenomenological continuum damage model. Crack growth and fracture are treated as the ultimate consequences of the damage process. Computationally, the initiation and growth of cracks is traced by an adaptive remeshing strategy, thereby allowing for opening crack faces. The application of the method to the fabrication of food-can lids demonstrates its capabilities, but also some of its limitations.

  17. Stability of the Area Law for the Entropy of Entanglement

    E-print Network

    Spyridon Michalakis

    2012-07-11

    Recent results on the stability of the spectral gap under general perturbations for frustration-free Hamiltonians, have motivated the following question: Does the entanglement entropy of quantum states that are connected to states satisfying an area law along gapped Hamiltonian paths, also satisfy an area law? We answer this question in the affirmative, combining recent advances in quasi-adiabatic evolution and Lieb-Robinson bounds with ideas from the proof of the 1D area law.

  18. Finite element simulation of fine blanking processes using a pressure-dependent damage model

    Microsoft Academic Search

    Ridha Hambli

    2001-01-01

    In order to accurately simulate fine blanking processes, a finite element model valid for numerically describing of such operations has been developed. The numerical simulation of the damage evolution and crack initiation and propagation have been described by means of continuum damage approach. In this paper, two models for damage accumulation has been implemented in the finite element code ABAQUS

  19. Micromechanical modeling of short glass-fiber reinforced thermoplastics-Isotropic damage of pseudograins

    Microsoft Academic Search

    S. Kammoun; L. Brassart; G. Robert; I. Doghri; L. Delannay

    2011-01-01

    A micromechanical damage modeling approach is presented to predict the overall elasto-plastic behavior and damage evolution in short fiber reinforced composite materials. The practical use of the approach is for injection molded thermoplastic parts reinforced with short glass fibers. The modeling is proceeded as follows. The representative volume element is decomposed into a set of pseudograins, the damage of which

  20. Damage Theory Applied to Flexural Fatigue Tests on Conventional and Asphalt Rubber Hot Mixes

    Microsoft Academic Search

    Luiz G. R. Mello; Kamil E. Kaloush; Márcio M. Farias

    2010-01-01

    Application of the Continuum Damage Theory (CDT) to evaluate the evolution of internal damage in Hot Mix Asphalt (HMA) is investigated in this paper. The CDT leads to the formulation of a characteristic curve relating normalized pseudo-stiffness and the internal damage variable, and this curve is supposed to be unique for each material. The uniqueness of the characteristic curve was

  1. Anisotropic Damage Analysis of HY100 Steel Under Quasistatic Loading Conditions

    SciTech Connect

    Los Alamos National Laboratory

    2001-01-01

    The effect of MnS inclusion orientation on damage evolution and fracture toughness in HYlOO steel is investigated in the context of anisotropic damage modeling at the continuum level. Experimental notched-bar data sets are analyzed and modeled using finite element calculations with constitutive behavior that assumes isotropic elastoplastic behavior in conjunction with anisotropic damage.

  2. Faculty of Law Faculty of Law

    E-print Network

    Faculty of Law Faculty of Law (141) Credit Hours Academic Year:2012/2013 Second: Faculty CompulsoryCourse No. -----------3Arabic Language Skills (1) 0110101 -----------3Military Sciences0111100 -----------3National Education9111101 -----------3English Language Skills (1) 0130101 University Electives:(15 credit

  3. Drug Laws and Drug Law Enforcement

    Microsoft Academic Search

    Edward M. Brecher

    1986-01-01

    The problem of drug use and abuse has been present in American society ever since its inception, and many different laws have been enacted, both at the federal and state level, to combat drug use. The question that arises is how effective have these laws been or what has their impact been on reducing drug use within the United States?

  4. Predicting bulk damage in NIF triple harmonic generators

    SciTech Connect

    De Yoreo, J; Runkel, M; Williams, W

    1998-09-18

    Recently reported experiments have investigated the statistics of laser damage in KDP and KD*P. Automated damage tests have allowed cumulative failure and damage probability distributions to be constructed. Large area tests have investigated the feasibility of on-line laser conditioning and damage evolution for tripler harmonic generation (THG) crystals on the National Ignition Facility (NIF). These tests have shown that there is a nonzero probability of damage at NIF redline fluence (14.3 J/cm2, 351 nm, 3 ns) and that the damage pinpoint density evolves exponentially with fluence. In this paper, the results of these tests are used in conjunction with model spatial profiles of the NIP beam to predict the level of damage created in the THG crystal. A probabilistic calculation based on the overlap of the beam fluence and damage probabiity distribution shows that the overall damage probability is less than 3% for well-conditioned, high quality KDP/KD*P crystals of conventional or rapid growth. The number density of generated pinpoints has been calculated by mapping the damage evolution curves onto the NlF model profile. This shows that the number of damage pinpoints generated in high fluence portions of the NIF beam will be low for well-conditioned THG crystals. In contrast, unconditioned triplers of the same material will exhibit an increase in pinpoint density of greater than 20x. To test the validity of these calculations a 37 cm, conventionally grown KD*P tripler from the Beamlet laser was scatter mapped for bulk damage. The tripler had been exposed to NE-like fluences during its operational lifetime on Beamlet and exhibited very low levels of bulk pinpoint damage, essentially supporting the predictions based on tests and modeling.

  5. Damage Tolerance of Composites

    NASA Technical Reports Server (NTRS)

    Hodge, Andy

    2007-01-01

    Fracture control requirements have been developed to address damage tolerance of composites for manned space flight hardware. The requirements provide the framework for critical and noncritical hardware assessment and testing. The need for damage threat assessments, impact damage protection plans, and nondestructive evaluation are also addressed. Hardware intended to be damage tolerant have extensive coupon, sub-element, and full-scale testing requirements in-line with the Building Block Approach concept from the MIL-HDBK-17, Department of Defense Composite Materials Handbook.

  6. A damage mechanics based approach to structural deterioration and reliability

    SciTech Connect

    Bhattcharya, B.; Ellingwood, B. [Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Civil Engineering

    1998-02-01

    Structural deterioration often occurs without perceptible manifestation. Continuum damage mechanics defines structural damage in terms of the material microstructure, and relates the damage variable to the macroscopic strength or stiffness of the structure. This enables one to predict the state of damage prior to the initiation of a macroscopic flaw, and allows one to estimate residual strength/service life of an existing structure. The accumulation of damage is a dissipative process that is governed by the laws of thermodynamics. Partial differential equations for damage growth in terms of the Helmholtz free energy are derived from fundamental thermodynamical conditions. Closed-form solutions to the equations are obtained under uniaxial loading for ductile deformation damage as a function of plastic strain, for creep damage as a function of time, and for fatigue damage as function of number of cycles. The proposed damage growth model is extended into the stochastic domain by considering fluctuations in the free energy, and closed-form solutions of the resulting stochastic differential equation are obtained in each of the three cases mentioned above. A reliability analysis of a ring-stiffened cylindrical steel shell subjected to corrosion, accidental pressure, and temperature is performed.

  7. Resonance rotation of celestial bodies and Cassini's laws

    Microsoft Academic Search

    V. V. Beletskii

    1972-01-01

    Celestial body rotation about its center of mass, taking into account the body orbit evolution, is considered. Non-linear evolution equations of motion are constructed. Empirical Cassini's laws describing the Moon motion result from these equations as their stationary points. Bifurcation conditions of steady motions are written out and conditions of their stability are investigated. Hypothesis of Mercury's resonance motion analogous

  8. Fundamental Laws of Algebra

    NSDL National Science Digital Library

    Blohowiak, Chad

    2005-01-01

    This learning object from Wisc-Online covers the fundamental laws of algebra. The interactive activity includes slides which cover the following topics: the commutative, associative and distributive laws as applied to addition and multiplication.

  9. The Modern Law Dean.

    ERIC Educational Resources Information Center

    Miller, John A.

    2000-01-01

    Asserting that law schools have entered an era when increasingly the law dean is a "rainmaker"--public envoy, professional fund raiser, and alumni booster. Considers implications for universities, colleges, faculties, students, and the deans themselves. (EV)

  10. Assistive Technology Laws

    MedlinePLUS

    ... Inclusion » View Item AT Fact Sheet: Assistive Technology Laws Back to Search Results There is a wide ... is important for families to understand how Federal laws affect their child’s right to AT. Provided below ...

  11. Mature Driver Laws

    MedlinePLUS

    Mature Driver Laws More and more Americans are outliving their ability to drive safely. As a result of impairments in three ... address this issue, many states have have enacted laws that contain specific licensing requirements for older drivers. ...

  12. Natural Resource and Environmental Law and Policy Minor (Code No. 670): 2010-11 Name: Last Update: Checksheet updated

    E-print Network

    Tullos, Desiree

    Natural Resource and Environmental Law and Policy Minor (Code No. 670): 2010-11 Name: Last Update) Evolution of U.S. Environmental and Nat. Res. Law AREC 253 (4) Environmental Law AREC 432 (4) Natural Resource Policy and Law FOR 462 (3) Select 16 credits from the list below Agricultural and Food Policy

  13. Generalized law for aftershocks

    NSDL National Science Digital Library

    Robert Shcherbakov

    A generalized law for aftershock decay rates is provided through the combination of the Gutenberg-Richter frequency magnitude relation, Bath's law, and the modified Omori's law. Several large quakes with readily identified aftershocks were studied. Results indicate that aftershock decay rates depended on several parameters specific to each seismic region. It was found that the law can be used to forecast the rate of aftershock occurrence after specific information about the main shock's magnitude and the area's land is known.

  14. Advertising Law Internet Site

    NSDL National Science Digital Library

    The Advertising Law Internet Site houses articles about the legal aspects of marketing products, with particular emphasis on infomercials, home shopping, and direct response TV. Other articles discuss 900 Number regulations, contest laws, business opportunity laws, and additional aspects of promotion law. The site also houses copies of FTC Guides and Speeches and FTC Rules and statutes. Consumer Advisories issued by the FTC will also be made available at the site.

  15. Health care law versus constitutional law.

    PubMed

    Hall, Mark A

    2013-04-01

    National Federation of Independent Business v. Sebelius, the Supreme Court's ruling on the Patient Protection and Affordable Care Act, is a landmark decision - both for constitutional law and for health care law and policy. Others will study its implications for constitutional limits on a range of federal powers beyond health care. This article considers to what extent the decision is also about health care law, properly conceived. Under one view, health care law is the subdiscipline that inquires how courts and government actors take account of the special features of medicine that make legal or policy issues especially problematic - rather than regarding health care delivery and finance more generically, like most any other economic or social enterprise. Viewed this way, the opinions from the Court's conservative justices are mainly about general constitutional law principles. In contrast, Justice Ruth Bader Ginsburg's dissenting opinion for the four more liberal justices is just as much about health care law as it is about constitutional law. Her opinion gives detailed attention to the unique features of health care finance and delivery in order to inform her analysis of constitutional precedents and principles. Thus, the Court's multiple opinions give a vivid depiction of the compelling contrasts between communal versus individualistic conceptions of caring for those in need, and between health care and health insurance as ordinary commodities versus ones that merit special economic, social, and legal status. PMID:23262771

  16. Finite element analysis of damage accumulation for structure under impact

    NASA Astrophysics Data System (ADS)

    Hongyan, Wang; Guixiang, Hao

    2011-07-01

    Responses of structure under impact load are different from quasi-static process and fatigue. Especially when the impact load is cyclic loading and unloading, damage of structure is different form that of structure under single continuous load. Random impact load usually has high peak value, thus material in structure may contain plastic strain, and damage evolution is non-linear. For cyclic loading and unloading, elastic recovery process should be considered. These characteristics make it difficult to compute damage in FEA. In the paper, we use FEM and damage theories to compute cumulative damage of certain metal structure under cyclic loading and unloading, and statistic method is used in load setting. A series of experiments were carried out to verify the simulated results. It is proved that FEM can be used to acquire cumulative damage of structure under cyclic loading and unloading, and the results may be referenced in engineering design.

  17. Validity of Thermodynamical Laws in Dark Energy Filled Universe

    E-print Network

    Samarpita Bhattacharya; Ujjal Debnath

    2010-12-26

    We have considered the flat FRW model of the universe which is filled with only dark energy. The general descriptions of first and second laws of thermodynamics are investigated on the apparent horizon and event horizon of the universe. We have assumed the equation of state of three different types of dark energy models. We have examined the validity of first and second laws of thermodynamics on apparent and event horizons for these dark energies. For these dark energy models, it has been found that on the apparent horizon, first and second laws are always valid. On the event horizon, the laws are break down for dark energy models 1 and 2. For model 3, first law cannot be satisfied on the event horizon, but second law may be satisfied at the late stage of the evolution of the universe and so the validity of second law on the event horizon depends on the values of the parameters only.

  18. Evolution of vortex knots

    NASA Astrophysics Data System (ADS)

    Ricca, Renzo L.; Samuels, David C.; Barenghi, Carlo F.

    1999-07-01

    For the first time since Lord Kelvin's original conjectures of 1875 we address and study the time evolution of vortex knots in the context of the Euler equations. The vortex knot is given by a thin vortex filament in the shape of a torus knot [script T]p,q (p>1, q>1; p, q co-prime integers). The time evolution is studied numerically by using the Biot Savart (BS) induction law and the localized induction approximation (LIA) equation. Results obtained using the two methods are compared to each other and to the analytic stability analysis of Ricca (1993, 1995). The most interesting finding is that thin vortex knots which are unstable under the LIA have a greatly extended lifetime when the BS law is used. These results provide useful information for modelling complex structures by using elementary vortex knots.

  19. Law of Large Numbers

    NSDL National Science Digital Library

    Grinstead, Charles M.

    Created by Charles M. Grinstead and J. Laurie Snell of Dartmouth College, this website is part of an online statistics textbook. Topics include: (1) Law of Large Numbers for Discrete Random Variables, (2) Chebyshev Inequality, (3) Law of Averages, (4) Law of Large Numbers for Continuous Random Variables, (5) Monte Carlo Method. There are several examples and exercises that accompany the material.

  20. Kepler and his Laws

    NSDL National Science Digital Library

    David Stern

    This lesson discusses the work of Tycho Brahe and his connection with Johannes Kepler. Students will receive an introduction to conic sections along with Kepler's laws and observe the mathematical formulation of the third law, and its explicit form for artificial Earth satellites. In addition, the student will confirm Kepler's third law by comparing orbital periods and mean distances for all major planets.

  1. Numerical simulation of welding induced damage and residual stress of martensitic steel 15-5PH

    Microsoft Academic Search

    T. Wu; M. Coret; A. Combescure

    2008-01-01

    This paper is about the modeling of damage and residual stresses induced by a complex history of thermo-elasto-plastic multiphase in welding heat affected zone (HAZ). A two-scale model for elasto-plastic damaged multiphase is developed. The constitutive equations of the model are coupling ductile damage, elasto-plastic strains, phase transformation and transformation plasticity. In this study, an equation of damage evolution is

  2. Experimental and theoretical studies for fatigue damage of short fiber reinforced metal

    Microsoft Academic Search

    Wei Shen; Dongning Chu; Lihua Peng; Jiachi Xu

    1995-01-01

    The fatigue damage variable D which is defined by the post-fatigue strain (PFFS) is introduced to study the overall damage-failure process of metal matrix composite (MMC) under cyclic loading. A fatigue damage evolution derived by means of the definition of fatigue damage and used to predict the fatigue life is presented in this paper.In addition, information on the crack propagation,

  3. Defect evolution during machining of brittle materials

    Microsoft Academic Search

    A. Chandra; K. P. Wang; Y. Huang; G. Subhash

    1997-01-01

    A simple stress based defect evolution model is developed to assess the influence of various process paramters on material removal rate (MRR) and induced damage during ceramic grinding processes. Model predictions for normal and lateral damage zones under normal indentations are first compared to fracture models as well as experimental observations on pyrex glass. The proposed model is then extended

  4. AN EXACTLY CONSERVATIVE PARTICLE METHOD FOR ONE DIMENSIONAL SCALAR CONSERVATION LAWS

    E-print Network

    AN EXACTLY CONSERVATIVE PARTICLE METHOD FOR ONE DIMENSIONAL SCALAR CONSERVATION LAWS YOSSI FARJOUN Cambridge MA 02139, USA Abstract. A particle scheme for scalar conservation laws in one space dimension resolutions. 1. Introduction Conservation laws are important models for the evolution of continuum quantities

  5. Damage-induced localized hypermutability

    PubMed Central

    Sterling, Joan F; Roberts, Steven A; Chao, Frank G; Xu, Hong; Zhang, Leilei; Walsh, Jesse; Resnick, Michael A

    2011-01-01

    Genome instability continuously presents perils of cancer, genetic disease and death of a cell or an organism. At the same time, it provides for genome plasticity that is essential for development and evolution. We address here the genome instability confined to a small fraction of DNA adjacent to free DNA ends at uncapped telomeres and double-strand breaks. We found that budding yeast cells can tolerate nearly 20 kilobase regions of subtelomeric single-strand DNA that contain multiple UV-damaged nucleotides. During restoration to the double-strand state, multiple mutations are generated by error-prone translesion synthesis. Genome-wide sequencing demonstrated that multiple regions of damage-induced localized hypermutability can be tolerated, which leads to the simultaneous appearance of multiple mutation clusters in the genomes of UV-irradiated cells. High multiplicity and density of mutations suggest that this novel form of genome instability may play significant roles in generating new alleles for evolutionary selection as well as in the incidence of cancer and genetic disease. PMID:21406975

  6. Conservation law of operator current in open quantum systems

    E-print Network

    J. Salmilehto; P. Solinas; M. Möttönen

    2012-03-08

    We derive a fundamental conservation law of operator current for master equations describing reduced quantum systems. If this law is broken, the temporal integral of the current operator of an arbitrary system observable does not yield in general the change of that observable in the evolution. We study Lindblad-type master equations as examples and prove that the application of the secular approximation during their derivation results in a violation of the conservation law. We show that generally any violation of the law leads to artificial corrections to the complete quantum dynamics, thus questioning the accuracy of the particular master equation.

  7. High-density Polyethylene Damage at Extreme Tensile Conditions

    NASA Astrophysics Data System (ADS)

    Brown, Eric; Furmanski, Jevan; Ramos, Kyle; Dattelbaum, Dana; Jensen, Brian; Iverson, Adam; Carlson, Carl; Fezzaa, Kamel; Trujillo, Carl; Martinez, Daniel; Gray, George; Patterson, Brian

    2013-06-01

    In situ and post mortem observations of the dynamic tensile failure and damage evolution of high-density polyethylene (HDPE) are made during Dynamic-Tensile-Extrusion (Dyn-Ten-Ext) loading. The Dyn-Ten-Ext technique probes the tensile response of materials at large strains (>1) and high strain-rates (>10,000/s) by firing projectiles through a conical die. Depending on the extrusion ratios and velocities, HDPE damage varies from gross deformation with substantial internal damage, to a stable jet with finite particulation, to catastrophic fragmentation. Postmortem sectioning elucidates a mechanism of internal damage inception and progression oblique to the extrusion axis. X-ray computed tomography corroborates a shear damage mechanism with an internal damage zone aligned with the extrusion axis. In situ measurements of damage are made with the impact system for ultrafast synchrotron experiments (IMPULSE) designed for using the advanced imaging and X-ray methods available at the Advanced Photon Source. Time resolved phase-contrast imaging elucidates the evolution of damage features during dynamic loading that is observed in post mortem sectioning and tomography.

  8. Evolution of Clinical Military Psychology Ethics

    Microsoft Academic Search

    Carrie H. Kennedy; Bret A. Moore

    2007-01-01

    Ethical quandaries for military psychologists are a challenge. Effective military mental health providers must have a thorough understanding of their ethics code, pertinent military instructions, military law, and the mental health laws of the countries in which they practice. This article traces the evolution of clinical military psychology ethics from World War II to present day and serves to introduce

  9. Philadelphia University Faculty of law

    E-print Network

    Philadelphia University Faculty of law Department of -------------- ---------- semester, 2007/2008 Course Syllabus Course code: 420141 Course Title: Public International Law (1) Course prerequisite (s) and/or corequisite (s): public international law 2, international human law and international Course

  10. Philadelphia University Faculty of law

    E-print Network

    Philadelphia University Faculty of law Department of -------------- ---------- semester, 2007/2008 Course Syllabus Course code: 410331 Course Title: International Trade Law Course prerequisite (s) and trade law Prerequisite: Introduction to commercial law Module number: 410331 Module number: 330270

  11. Philadelphia University Faculty of law

    E-print Network

    /or corequisite (s): Specialization elective requirement- Labor Law Course Level: fourth year Credit hours: 3 description: Module name: The social security law Prerequisite: Labor law Module number: 410318 Module numberPhiladelphia University Faculty of law Department of -------------- ---------- semester, 2007

  12. Laser Damage Lab

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Optical Damage Threshold Testing Instrumentation at NASA Langley Research Center. This work was sanctioned and funded by Code Q, R, & AE to develop a new standard for damage testing various types of optical materials and coatings. Laser Induced Damage Threshold (LIDT) testing is a destructive test procedure to determine the minimum applied laser energy level that will result in damage and is referred to as the damage threshold. The damage threshold is often the critical limitation in the section of optical materials for use in high-energy laser systems.The test station consists of diagnostic equipment, beam conditioning optical elements, an inspection microscope and three lasers: a high energy pulsed ND: Yag, which develops 650mJ at 10 hz and outputs three wavelengths which include 1.06m, 532nm and 355 nm; a Ti:sapphire laser which produces a continuum of laser output from 790nm to 900nm; and a alignment HeNe, which looks yellow when mixed with the 2nd harmonic ND:Yag laser. Laser sources are used to perform damage threshold testing at the specific wavelength of interest.

  13. DNA Damage Response

    PubMed Central

    Giglia-Mari, Giuseppina; Zotter, Angelika; Vermeulen, Wim

    2011-01-01

    Structural changes to DNA severely affect its functions, such as replication and transcription, and play a major role in age-related diseases and cancer. A complicated and entangled network of DNA damage response (DDR) mechanisms, including multiple DNA repair pathways, damage tolerance processes, and cell-cycle checkpoints safeguard genomic integrity. Like transcription and replication, DDR is a chromatin-associated process that is generally tightly controlled in time and space. As DNA damage can occur at any time on any genomic location, a specialized spatio-temporal orchestration of this defense apparatus is required. PMID:20980439

  14. The Legitimacy of Punitive Damages in Media Libel Cases.

    ERIC Educational Resources Information Center

    Thomas, James H.

    The constitutionality of punitive damage awards in media defamation litigation was examined through a review of federal and state libel case law since the 1964 Supreme Court decision in "New York Times v. Sullivan." Using the opinions of various courts and justices and studies of libel litigation, a number of areas bearing on the issue were…

  15. Undergraduate Handbook School of Law

    E-print Network

    Hickman, Mark

    Undergraduate Handbook School of Law Critique. LLB 2013LAW #12;Contents 1 From the Dean Welcome to the School of Law 3 Law degrees at UC 4 Double degrees at UC 5 Planning your degree 6 Specialisations & career opportunities 9 Law School staff 11 2013 course supervisors 12 Law facilities 14 Academic

  16. Nonlinear viscoelastic and viscoplastic constitutive equations with growing damage

    Microsoft Academic Search

    R. A. Schapery

    1999-01-01

    Nonequilibrium thermodynamics, rate-process theory, viscoelastic fracture mechanics and various experimentally-motivated simplifications\\u000a are used to develop constitutive equations that account for effects of viscoelasticity, viscoplasticity, growing damage and\\u000a aging. Their form is more general than previously developed by the author, and allows for relatively general tensorial effects\\u000a of damage. Some important special cases are then covered, with emphasis on viscoelasticity. Evolution

  17. Comparison of GTN damage models for sheet metal forming

    Microsoft Academic Search

    Zhi-ying Chen; Xiang-huai Dong

    2008-01-01

    The Gurson-Tvergaard-Needleman (GTN) damage model was developed basing on anisotropic yield criterion to predict the damage\\u000a evolution for anisotropic voided ductile materials. Hill’s quadratic anisotropic yield criterion (1948) and Barlat’s 3-component\\u000a anisotropic yield criterion (1989) were used to describe the anisotropy of the matrix. User defined subroutines were developed\\u000a using the above models. Taking the benchmark of NUMISHEET’93 square cup

  18. Controlling Opossum Damage 

    E-print Network

    Texas Wildlife Services

    2007-05-23

    damage; however, their pelts can be sold only during the furbearer season and with the proper licenses. Other furbearers include beaver, otter, mink, nutria, ringtailed cat, badger, skunk, weasel, raccoon, muskrat, fox and civet cat. Homeowners...

  19. LSD and Genetic Damage

    ERIC Educational Resources Information Center

    Dishotsky, Norman I.; And Others

    1971-01-01

    Reviews studies of the effects of lysergic acid diethylamide (LSD) on man and other organisms. Concludes that pure LSD injected in moderate doses does not cause chromosome or detectable genetic damage and is not a teratogen or carcinogen. (JM)

  20. Controlling Beaver Damage

    E-print Network

    Texas Wildlife Services

    2007-03-13

    Damage Controlling BEAVER B eavers (Castor canadensis) are the largest rodents in North America. Their range includes most of North America, from the northern parts of Canada and Alaska to northern Mexico. Beavers are aquatic rodents which live...

  1. Court Disallows Damage Claims

    ERIC Educational Resources Information Center

    Tomson, Bernard; Coplan, Norman

    1976-01-01

    In rejecting claims for damages, the Court finds that contract's "increase or decrease of cost" language is not applicable to added overhead costs and loss of labor efficiency resulting from delays over which the contractor has no control. (Author)

  2. DAMAGING AGENTS AND PROTECTION

    E-print Network

    Standiford, Richard B.

    limit the longevity of individual oaks. People who manage oak trees or woodlands are concerned of the ecological relationships between oaks and damaging agents. Oaks evolved under the challenge of various

  3. Controlling Woodpecker Damage 

    E-print Network

    Texas Wildlife Damage Management Service

    2008-04-15

    Several species of woodpeckers, flickers and sapsuckers live in Texas. They can be destructive when they drill holes in wooden structures. This publication discusses various controls and alternative methods for eliminating noise and damage....

  4. Controlling Armadillo Damage 

    E-print Network

    Texas Wildlife Services

    2007-03-13

    Armadillos are beneficial because they eat insects and other invertebrates, but they can damage lawns, gardens and structural foundations. They also are believed to transmit leprosy to humans. This leaflet focuses on control methods such as trapping...

  5. Northridge, CA Earthquake Damage

    USGS Multimedia Gallery

    The person in this image was a USGS employee at the time this was taken. Collection of USGS still images taken after the January 17, 1994 Northridge earthquake highlighting the damage to buildings and infrastructure....

  6. Composites Damage Tolerance Workshop

    NASA Technical Reports Server (NTRS)

    Gregg, Wayne

    2006-01-01

    The Composite Damage Tolerance Workshop included participants from NASA, academia, and private industry. The objectives of the workshop were to begin dialogue in order to establish a working group within the Agency, create awareness of damage tolerance requirements for Constellation, and discuss potential composite hardware for the Crew Launch Vehicle (CLV) Upper Stage (US) and Crew Module. It was proposed that a composites damage tolerance working group be created that acts within the framework of the existing NASA Fracture Control Methodology Panel. The working group charter would be to identify damage tolerance gaps and obstacles for implementation of composite structures into manned space flight systems and to develop strategies and recommendations to overcome these obstacles.

  7. Controlling Feral Hog Damage 

    E-print Network

    Texas Wildlife Services

    2008-04-15

    This publication discusses the distribution of feral hogs as well as their habitats, food habits and reproduction. Feral hogs can damage crops and kill lambs and kid goats. Methods of control are also explained....

  8. On Hack's Law

    NASA Astrophysics Data System (ADS)

    Rigon, Riccardo; Rodriguez-Iturbe, Ignacio; Maritan, Amos; Giacometti, Achille; Tarboton, David G.; Rinaldo, Andrea

    1996-11-01

    Hack's law is reviewed, emphasizing its implications for the elongation of river basins as well as its connections with their fractal characteristics. The relation between Hack's law and the internal structure of river basins is investigated experimentally through digital elevation models. It is found that Hack's exponent, elongation, and some relevant fractal characters are closely related. The self-affine character of basin boundaries is shown to be connected to the power law decay of the probability of total contributing areas at any link and to Hack's law. An explanation for Hack's law is derived from scaling arguments. From the results we suggest that a statistical framework referring to the scaling invariance of the entire basin structure should be used in the interpretation of Hack's law.

  9. Plaintiff injury and defendant reprehensibility: Implications for compensatory and punitive damage awards

    Microsoft Academic Search

    Corinne Cather; Edith Greene; Robert Durham

    1996-01-01

    A criticism of the civil jury is that jurors' decisions about damages are capricious and arbitrary. In particular, critics point to the skyrocketing nature of punitive damage assessments as evidence of a system run amok. The purpose of this study was to examine the factors that influence jurors' decisions about compensatory and punitive awards. We assess whether, as the law

  10. Age Discrimination: Monetary Damages under the Federal Age Discrimination in Employment Act.

    ERIC Educational Resources Information Center

    Butler, Richard

    1979-01-01

    Since the Age Discrimination in Employment Act is a remedial act, a wide range of damages should be available in the absence of compelling arguments in favor of severely restricting the type of damages recoverable. Available from the Managing Editor, Nebraska Law Review, University of Nebraska, Lincoln, Nebraska 68583; sc $3.00. (Author/IRT)

  11. The use of coupled nonlocal damage-plasticity to predict crack growth in ductile metal plates

    Microsoft Academic Search

    Jonathan P. Belnoue; Barry Garnham; Martin Bache; Alexander M. Korsunsky

    2010-01-01

    A nonlocal coupled damage-plasticity model is presented for predicting crack growth within plates made from a ductile metallic alloy. The damage law is explicitly defined in terms of the accumulated nonlocal plastic strain ensuring efficient numerical implementation. On the basis of this model, a UMAT for the finite element (FE) package ABAQUS (implicit) is developed. Thin plates of different geometries

  12. A damage model for ductile crack initiation and propagation , N. Van Goethem+

    E-print Network

    Lisbon, University of

    A damage model for ductile crack initiation and propagation P. Areias , N. Van Goethem+ , E-001 Lisboa, Portugal ICIST Abstract Damage-induced ductile crack initiation and propagation is modeled using laws take into account pressure sensitivity and the Lode angle effect in the fracture strain. Two plane

  13. Rate Tornado Damage

    NSDL National Science Digital Library

    Tornadoes can produce damage that ranges from broken tree limbs to a block of houses swept from their foundations. They can inflict utter devastation across a wide swath of land or, destroy one house and leave others on either side largely untouched. In this interactive feature from NOVA Online, sudents examine a series of photos of tornado damage and assign intensity ratings (on the Fulita scale) based on what they see.

  14. Rate Tornado Damage

    NSDL National Science Digital Library

    Lexi Krock

    An interactive Flash animation that educates students about the Fujita scale for rating tornado wind speeds and the damage caused by tornados. After being presented with photographs of tornado damage, students are challenged to assign the tornado a rating on the F-scale. The interactive explains the different levels of the F-scale and provides instant feedback on whether or not the correct category was assigned to the tornado.

  15. Newton's Second Law

    NSDL National Science Digital Library

    John Pratte

    This lesson introduces students to Sir Isaac Newton's Second Law of Motion. Topics include the two ways to study the dynamics of a system in which there is motion, a brief description of Newton's work in studying and measuring the motion of objects, and a summary of his three laws of motion. The lesson includes an activity in which students test Newton's Second Law by measuring the acceleration of a cart which is being pulled by increasingly larger masses.

  16. Non standard thermodynamics framework for robust computations with induced anisotropic damage

    E-print Network

    -dissipation potential for the second one. The elasticity law and the strain energy release rate density YYY , variable of thermodynamics a pseudo-dissipation po- tential quadratic function of YYY is most often considered, the damage law taking the form DDD = JJJ : YYY (1) with a positive multiplier and JJJ a positive fourth order

  17. Non standard thermodynamics framework for robust computations with induced anisotropic damage

    E-print Network

    . The elasticity law and the strain energy release rate density YYY , variable associated with DDD- tential quadratic function of YYY is most often considered, the damage law taking the form DDD = JJJ : YYY (1) with a positive multiplier and JJJ a positive fourth order tensor, eventually nonlinear

  18. Bullying Policies and Laws

    MedlinePLUS

    ... Policies & Laws | Espańol Search Stopbullying.gov WHAT IS BULLYING Definition The Roles Kids Play Related Topics CYBER BULLYING What is Cyberbullying? Prevent Cyberbullying Report Cyberbullying WHO ...

  19. Customary law row looming.

    PubMed

    Khumalo, B

    1993-11-01

    Married women under customary law in South Africa are perpetual minors; customary law marriages are not of equal status to civil law marriages; women are denied inheritance access to land and property and excluded from decision making in their homes and communities; and Muslim women do not have equal rights under Muslim personal law. As political and civil reforms loom on the horizon in South Africa, however, calls are being made for customary law to be included under the scrutiny of the Bill of Rights. Women under customary law would therefore be protected under an uniform Bill of Rights. Members of the Congress of Traditional Leaders are staunchly opposed to such a move. They argue instead that women under customary law should not be protected in the Bill of Rights. Customary law will therefore be insulated from legislative reform. This paper briefly presents segments of the ongoing debate between law academics, women's pressure groups, and religious and cultural bodies on the issue. PMID:12345311

  20. Infrared thermography of damage evaluation in leather products

    NASA Astrophysics Data System (ADS)

    Luong, Minh Phong

    1999-05-01

    The paper aims to illustrate three advantages of infrared thermography as a non-destructive, non-contact and real-time technique (a) to observe the progressive damage processes and failure mechanisms of leather, (b) to detect the occurrence of intrinsic dissipation localization, and (b) to evaluate a threshold of acceptable damage. The parameter, investigated in this paper, is the heat generation due to intrinsic dissipation caused by anelasticity and/or inelasticity of leather. It readily describes the damage location and the failure evolution of leather for sport foot-wear.

  1. EOS Laser Atmosphere Wind Sounder (LAWS) investigation

    NASA Technical Reports Server (NTRS)

    1996-01-01

    In this final report, the set of tasks that evolved from the Laser Atmosphere Wind Sounder (LAWS) Science Team are reviewed, the major accomplishments are summarized, and a complete set of resulting references provided. The tasks included preparation of a plan for the LAWS Algorithm Development and Evolution Laboratory (LADEL); participation in the preparation of a joint CNES/NASA proposal to build a space-based DWL; involvement in the Global Backscatter Experiments (GLOBE); evaluation of several DWL concepts including 'Quick-LAWS', SPNDL and several direct detection technologies; and an extensive series of system trade studies and Observing System Simulation Experiments (OSSE's). In this report, some of the key accomplishments are briefly summarized with reference to interim reports, special reports, conference/workshop presentations, and publications.

  2. Scaling Laws in Magnetohydrodynamic Turbulence

    E-print Network

    Leonardo Campanelli

    2004-10-04

    We analyze the decay laws of the kinetic and magnetic energies and the evolution of correlation lengths in freely decaying incompressible magnetohydrodynamic (MHD) turbulence. Scale invariance of MHD equations assures that, in the case of constant dissipation parameters ({\\it i.e.} kinematic viscosity and resistivity) and null magnetic helicity, the kinetic and magnetic energies decay in time as $E \\sim t^{-1}$, and the correlation lengths evolve as $\\xi \\sim t^{1/2}$. In the helical case, assuming that the magnetic field evolve towards a force-free state, we show that (in the limit of large magnetic Reynolds number) the magnetic helicity remains constant, the kinetic and magnetic energies decay as $E_v \\sim t^{-1}$ and $E_B \\sim t^{-1/2}$ respectively, while both the kinetic and magnetic correlation lengths grow as $\\xi \\sim t^{1/2}$.

  3. A Data Analysis for the Inverse Square Law

    ERIC Educational Resources Information Center

    Downie, Russell

    2007-01-01

    When first encountered, inverse square laws can damage the confidence of beginning physics students whose maths skills are uncertain. Engaging in practical exercises that help them work with the idea can be a great help. We have used the following apparatus for a number of years and our students understand and enjoy the exercise.

  4. A Data Analysis for the Inverse Square Law

    NASA Astrophysics Data System (ADS)

    Downie, Russell

    2007-04-01

    When first encountered, inverse square laws can damage the confidence of beginning physics students whose maths skills are uncertain. Engaging in practical exercises that help them work with the idea can be a great help. We have used the following apparatus for a number of years and our students understand and enjoy the exercise.

  5. The Concept of ‘Law’ in Global Administrative Law

    Microsoft Academic Search

    Benedict Kingsbury

    2009-01-01

    What constitutes ‘law’ in the efflorescent field of ‘global administrative law’? This article argues for a ‘social fact’ conception of law, emphasizing sources and recognition criteria, but it extends this Hartian positivism to incorporate requirements of ‘publicness’ in law. ‘Publicness’ is immanent in public law in national democratic jurisprudence, and increasingly in global governance, where it applies to public entities

  6. Environmental Law and Policy: Nature, Law and Society

    Microsoft Academic Search

    Zygmunt J. B. Plater; Robert H Abrams; Robert L Graham; Lisa Heinzerling; David A Wirth; Noah D Hall

    2010-01-01

    This user-friendly book - noted for its comprehensive legal process approach to the depth and complexity of modern environmental law - gives students a solid doctrinal footing in the law and helps build their analytical skills. Environmental Law and Policy: Nature, Law, and Society, Fourth Edition, uses the legal process approach, building on a base of common law and constitutional

  7. LawGuru.com

    NSDL National Science Digital Library

    LawGuru.com is an exhaustive resource for free legal information. The site provides access to more than 430 legal search engines and databases, including a feature that allows parallel searching of multiple databases. The site also maintains the LawGuru.com BBS, a searchable database of legal questions posted by users accompanied by responses from one of the more than 320 practicing attorneys in the LawGuru.com network. Currently the BBS database contains over 4,000 legal questions divided into more than 25 categories. In addition, LawGuru.com provides a collection of fifteen FAQs written on various legal issues, links to over 500 legal Internet resources, and information on over 600 associated electronic mailing lists. Recently, LawGuru.com began hosting the Internet Law Library (see the May 3, 1996 Scout Report), a comprehensive resource formerly maintained by the US House of Representatives. LawGuru.com is operated by The Law Offices of Eslamboly & Barlavi (California).

  8. Teachers and the Law.

    ERIC Educational Resources Information Center

    Fischer, Louis; And Others

    This book is designed to promote legal literacy for public school teachers. It examines a wide range of constitutional, statutory, and case law that directly affects their work. Its purpose is to provide teachers with the knowledge necessary to comply with the law, assert their rights, and bring violations to the attention of administrators and…

  9. Kepler's Law of Refraction

    Microsoft Academic Search

    R. A. Houstoun

    1939-01-01

    In his review of the second volume of the new edition of Kepler's works in Nature of August 19, p. 306, Prof. H. C. Plummer states that Kepler's formula for the law of refraction is alpha - beta = kappaalpha sec beta, where alpha is the angle of incidence and beta the angle of refraction. This reduces to the law

  10. Women Law Professors.

    ERIC Educational Resources Information Center

    Fossum, Donna

    1980-01-01

    Women have made considerable progress toward becoming part of tenure-track legal faculties, but women law professors continue to be academically disproportionately inbred and overrepresented in some areas, such as family law and legal research and writing. (Journal availability: American Bar Foundation, 1155 E. 60th St., Chicago, IL 60637.) (MSE)

  11. Science and the Law.

    ERIC Educational Resources Information Center

    Kennedy, Donald; Merrill, Richard A.

    2000-01-01

    Explaines the role of the Carnegie Commission which was formed to explore the relationship between the disciplines of science, technology, and the law. Discusses concerns about the individual right of privacy in projects such as the Human Genome Project. Focuses on the panel on Science, Technology, and Law which was established in 1999. (YDS)

  12. The Law of Elasticity

    ERIC Educational Resources Information Center

    Cocco, Alberto; Masin, Sergio Cesare

    2010-01-01

    Participants estimated the imagined elongation of a spring while they were imagining that a load was stretching the spring. This elongation turned out to be a multiplicative function of spring length and load weight--a cognitive law analogous to Hooke's law of elasticity. Participants also estimated the total imagined elongation of springs joined…

  13. Indian Law Enforcement History.

    ERIC Educational Resources Information Center

    Etheridge, David

    Written as a tribute to American Indian law enforcement officers and the Indian Criminal Justice System, this monographh details the history of the legislative, judicial, financial, and cultural problems associated with the development of Indian law enforcement. Citing numerous court cases, pieces of legislation, and individual and organizational…

  14. Linear Laws in Physics

    NASA Astrophysics Data System (ADS)

    Wang, Liqiu

    The empirical laws in physics, relating two frame-indifferent spatial vectors linearly, are shown to be both necessary and sufficient condition for a general linear relation between two vectors to satisfy the principle of material frame indifference, a more universal law in physics.

  15. Linear Laws in Physics

    Microsoft Academic Search

    Liqiu Wang

    1998-01-01

    The empirical laws in physics, relating two frame-indifferent spatial vectors linearly, are shown to be both necessary and sufficient condition for a general linear relation between two vectors to satisfy the principle of material frame indifference, a more universal law in physics.

  16. School of Law Scholarships

    E-print Network

    Almor, Amit

    School of Law Scholarships Complete Scholarship Name Application Deadline Date Contact Name Contact This scholarship was created in March 2010 by the American College of Trial Lawyers to support programs of Admissions 803.777.6605 usclaw@law.sc.edu Andrew J. Savage Scholarship Endowment Fund The Andrew J. Savage

  17. Law and You.

    ERIC Educational Resources Information Center

    Schurr, Sandra

    Fourteen activity units are presented to help elementary and junior high students learn about laws, rules, and respect for others. A pretest introduces the materials by asking students why society has rules and laws, which ones apply to children, and what reactions students have to the word "cop." The subsequent units involve the students in group…

  18. Partnering with Law Enforcement.

    ERIC Educational Resources Information Center

    Justin, Terry

    1997-01-01

    The benefits of child support enforcement programs collaborating with law enforcement include the timely identification of fraudulent cases and increased information access. Welfare reform legislation allows funding to assist law enforcement agencies that provide child support enforcement services. The creation of a Criminal Child Support…

  19. School Law Update, 1986.

    ERIC Educational Resources Information Center

    Jones, Thomas N., Ed.; Semler, Darel P., Ed.

    A wide variety of contemporary legal issues, involving all levels of public and private education, are addressed in the 20 separate chapters comprising this volume. The titles and authors of the chapters are as follows: (1) Due Process of Law: Loudermill v. Cleveland Board of Education (Hooker); (2) Schools, Technology and the Law (Helm); (3)…

  20. Microstructural evolution during dynamic deformation of cubic metals: copper

    SciTech Connect

    Cerreta, Ellen K [Los Alamos National Laboratory; Koller, Darcie D [Los Alamos National Laboratory; Bronkhorst, Curt A [Los Alamos National Laboratory; Excobedo, Juan P [Los Alamos National Laboratory; Hansen, Benjamin L [Los Alamos National Laboratory; Patterson, Brian M [Los Alamos National Laboratory; Lebensohn, Ricardo A [Los Alamos National Laboratory; Livescu, Veronica [Los Alamos National Laboratory; Tonks, Davis [Los Alamos National Laboratory; Mourad, Hashem M [Los Alamos National Laboratory; Germann, Timothy C [Los Alamos National Laboratory; Perez - Bergquist, Alex [Los Alamos National Laboratory; Gray Ill, George T [Los Alamos National Laboratory

    2010-12-22

    Shockwave shape can influence dynamic damage evolution. Features such as rise time, pulse duration, peak shock pressure, pull back, and release rate are influenced as wave shape changes. However, their individual influence on dynamic damage evolution is not well understood. Specifically, changing from a square to triangular or Taylor wave loading profile can alter the release kinetics from peak shock pressure and the volume of material sampled during release. This creates a spatial influence. In high purity metals, because damage is often linked to boundaries within the microstructure (grain or twin), changing the volume of material sampled during release, can have a drastic influence on dynamic damage evolution as the number of boundaries or defects sampled is altered. In this study, model-driven dynamic experiments have been conducted on eu with four different grain sizes to examine, for a given shockwave shape, how the spatial effect of boundary distribution influences dynamic damage evolution. Both two and three dimensional damage characterization techniques have been utilized. This study shows the critical influence of spatial effects, in this case boundary density, on dynamic damage evolution. As the boundary density decreases, the damage evolution transitions from nucleation controlled to growth controlled. It also shows that specific boundaries, those with high Schmid factor orientations on either side, maybe a necessary condition for void formation.

  1. Reducing Radiation Damage

    SciTech Connect

    Blankenbecler, Richard

    2006-06-05

    This talk describes the use of a modified treatment sequence, i.e., radiation dose, geometry, dwell time, etc., to mitigate some of the deleterious effects of cancer radiotherapy by utilizing natural cell repair processes. If bad side effects can be reduced, a more aggressive therapy can be put into place. Cells contain many mechanisms that repair damage of various types. If the damage can not be repaired, cells will undergo apoptosis (cell death). Data will be reviewed that support the fact that a small dose of radiation will activate damage repair genes within a cell. Once the mechanisms are fully active, they will efficiently repair the severe damage from a much larger radiation dose. The data ranges from experiments on specific cell cultures using microarray (gene chip) techniques to experiments on complete organisms. The suggested effect and treatment is consistent with the assumption that all radiation is harmful, no matter how small the dose. Nevertheless, the harm can be reduced. These mechanisms need to be further studied and characterized. In particular, their time dependence needs to be understood before the proposed treatment can be optimized. Under certain situations it is also possible that the deleterious effects of chemotherapy can be mitigated and the damage to radiation workers can be reduced.

  2. [Compulsory admission to hospital in Tunisia: a necessary evolution].

    PubMed

    Ellouze, Faten; Lahmar, Aymen; Beji, Rami; Dridi, Anis; Fadhel M'rad, Mohamed

    2015-01-01

    The evolution of the legislation governing compulsory admission to hospital in Tunisia is interesting for two reasons. The country's 2011 revolution notably brought about major changes to the legislative framework, from constitutional through to ordinary laws. At the same time, the current trend for globalisation is also affecting legislation: international laws, treaties and UN charters are imposed on the laws of individual countries. This article looks at how Tunisian law governing compulsory admission to hospital has had to evolve. PMID:26143219

  3. Duke Law & Technology Review

    NSDL National Science Digital Library

    Law school students are well known for trying to "do good" whether it be through aiding wrongly accused persons, or by providing legal advice at any number of free clinics. This academic and policy-oriented online publication from the people at Duke University's Law School is another such endeavor, and one that is worth a closer look. The publication's general area of interest is in the intersection of law and technology, and as such it draws on the knowledge base of specialties that include business law and intellectual property. The school's Law & Technology Review consists primarily of short issues briefs that provide insight into a wide range of issues for both the legal community and professionals working in these areas more broadly. Visitors to the site can browse the different briefs through a listing of general thematic areas or merely scroll through the site's homepage.

  4. Damage Tolerance Assessment Branch

    NASA Technical Reports Server (NTRS)

    Walker, James L.

    2013-01-01

    The Damage Tolerance Assessment Branch evaluates the ability of a structure to perform reliably throughout its service life in the presence of a defect, crack, or other form of damage. Such assessment is fundamental to the use of structural materials and requires an integral blend of materials engineering, fracture testing and analysis, and nondestructive evaluation. The vision of the Branch is to increase the safety of manned space flight by improving the fracture control and the associated nondestructive evaluation processes through development and application of standards, guidelines, advanced test and analytical methods. The Branch also strives to assist and solve non-aerospace related NDE and damage tolerance problems, providing consultation, prototyping and inspection services.

  5. Child Labor Laws in Mississippi.

    ERIC Educational Resources Information Center

    Robbins, Jerry H.

    Child labor laws have not attracted much attention in recent years. Much of the basic legislation and the case law dates from the early part of the 20th century. This paper discusses the Mississippi statutory law on the subject, compares that law with legislation in five other States, and discusses case law in Mississippi and in other States.…

  6. Cardiff Law School Postgraduate Programmes

    E-print Network

    Davies, Christopher

    Cardiff Law School Postgraduate Programmes www.law.cardiff.ac.uk #12;Welcome from the Head Professional Legal Training: LPC, BPTC, GDL and LLM Legal Practice 10 LLM Canon Law 10 LLM European Legal Studies 11 LLM Governance and Devolution 12 LLM Human Rights Law 12 LLM International Commercial Law 13

  7. Philadelphia University Faculty of Law

    E-print Network

    Contracts · 410315 Labor Law · 410323 Commercial Papers & Banking Transactions · 410391 Law of Civil1 Philadelphia University Faculty of Law Curriculum Details Academic Year: 2004/2005 Study Plan for Bachelor Degree of Law Modules Descriptions #12;2 Study Plan for Bachelor Degree of Law / Academic Year

  8. The Evolution and Development of the Universe

    E-print Network

    Clement Vidal; Charles Auffray; Alex H. Blin; Jean Chaline; Louis Crane; Thomas Durt; Borje Ekstig; Horace Fairlamb; Jan Greben; Rob Hengeveld; Francis Heylighen; Gerard Jagers op Akkerhuis; Giuseppe Longo; Nicolas F. Lori; Denis Noble; Laurent Nottale; Franc Rottiers; Stanley Salthe; John Stewart; Ruediger Vaas; Gertrudis Van de Vijver; Nico M. van Straalen

    2010-01-04

    This document is the Special Issue of the First International Conference on the Evolution and Development of the Universe (EDU 2008). Please refer to the preface and introduction for more details on the contributions. Keywords: acceleration, artificial cosmogenesis, artificial life, Big Bang, Big History, biological evolution, biological universe, biology, causality, classical vacuum energy, complex systems, complexity, computational universe, conscious evolution, cosmological artificial selection, cosmological natural selection, cosmology, critique, cultural evolution, dark energy, dark matter, development of the universe, development, emergence, evolution of the universe evolution, exobiology, extinction, fine-tuning, fractal space-time, fractal, information, initial conditions, intentional evolution, linear expansion of the universe, log-periodic laws, macroevolution, materialism, meduso-anthropic principle, multiple worlds, natural sciences, Nature, ontology, order, origin of the universe, particle hierarchy, philosophy, physical constants, quantum darwinism, reduction, role of intelligent life, scale relativity, scientific evolution, self-organization, speciation, specification hierarchy, thermodynamics, time, universe, vagueness.

  9. Teaching American Law to French Law Students--in English.

    ERIC Educational Resources Information Center

    Sultan, Allen

    1978-01-01

    Described is the history and academic activity of the program, offered in English, to French law students, at the Center for the Study of English and American Law. The program includes instruction in law, along with English language instruction. (JMD)

  10. Damage Control Orthopaedics

    Microsoft Academic Search

    Julie M. Keller; Andrew N. Pollak

    \\u000a University of Maryland School of Medicine\\u000a \\u000a Julie M. Keller MD, Andrew N. Pollak MD\\u000a \\u000a \\u000a In damage control for trauma patients, the main tenets are to perform temporary operative procedures to provide time for physiologic\\u000a stabilization before definitive surgical care. There are four distinct phases of the damage control philosophy: the first\\u000a is recognition of the at risk patient; next, temporizing

  11. Monitoring low cycle fatigue damage in turbine blade using vibration characteristics

    NASA Astrophysics Data System (ADS)

    Kumar, Sandeep; Roy, Niranjan; Ganguli, Ranjan

    2007-01-01

    A finite element based approach is used to simulate the evolution of low cycle fatigue damage in a turbine blade. The turbine blade is modelled as a rotating Timoshenko beam with taper and twist. A damage growth model for low cycle fatigue damage developed using a continuum mechanics approach is integrated with the finite element model. Numerical results are obtained to study the effect of damage growth on the rotating frequencies. It is found that low cycle fatigue causes sufficient degradation in blade stiffness for changes in rotating frequency to be used as an indicator to track damage growth. Continuum damage mechanics models in conjunction with finite element analysis are used to develop thresholds for damage indicators. By placing suitable threshold on the frequency change, it is possible to detect the onset of the final stage of damage in the structure before failure occurs.

  12. The new energy law

    SciTech Connect

    Allen, Z.

    1997-05-01

    Foreign companies, as well as Polish companies, have long awaited the introduction of a new environment for doing business in Poland`s energy sector. The adoption by the Sejm (lower house of the Polish Parliament) of a new Energy Law (Prawo Energetyczne) promises to move Poland into a brave new world for energy sector businesses. With this law, Poland hopes to leapfrog into the vanguard of European countries in terms of privatization and demonopolization of its energy sectors. Only the United Kingdom may be more progressive in this regard. During the past several months, a draft law was passed by the Sejm and sent to the Senate. The Senate introduced nearly 50 changes, passed the law and returned it to the Sejm. At that point, the Sejm committee responsible for this law recommended against almost all the Senate`s changes, returning the draft law to its original form. The actions by the Sejm, now awaited, will be final with only the signature of the president needed to put the law into force. Subsequently, this examination of the law is based upon the draft as originally passed by the Sejm and expected to be signed by Poland`s president. There are several key provisions of the proposed new law that make it so different from the current regulatory structure. The key terms that the Polish government likes to use are privatization and demonopolization, of which the latter is to come first. It is a leap forward from an energy sector that was owned entirely by the State, and where prices at all levels, from the coal mines to the residential consumer, were set without regard to cost.

  13. FindLaw Constitutional Law Center

    NSDL National Science Digital Library

    This offering from FindLaw (last discussed in the January 15, 1999 Scout Report) focuses on the US Constitution. The site is composed of two primary sections. The first offers an annotated Constitution, commentary on selected topics with links to key sections of the Constitution or The Federalist Papers, a history of the Constitution, and brief biographies of notable "Founding Fathers" and delegates to the Constitutional Convention. The second section highlights the Third Branch of government, with a history of the Supreme Court, landmark decisions regarding civil rights with the full opinions, a summary and analysis of the criminal law and procedure decisions of the October 1998 Supreme Court Term, and several links for current Supreme Court news and information. Both sections also feature a search engine. Additional resources at the site include a Town Hall section that explores Hot Topics (currently flag burning) and message boards on a wide variety of Constitutional issues.

  14. FindLaw Constitutional Law Center

    NSDL National Science Digital Library

    This latest offering from FindLaw (last discussed in the January 15, 1999 Scout Report) focuses on the US Constitution. The site is composed of two primary sections. The first offers an annotated Constitution, commentary on selected topics with links to key sections of the Constitution or The Federalist Papers, a history of the Constitution, and brief biographies of notable "Founding Fathers" and delegates to the Constitutional Convention. The second section highlights the Third Branch of government, with a history of the Supreme Court, landmark decisions regarding civil rights with the full opinions, a summary and analysis of the criminal law and procedure decisions of the October 1998 Supreme Court Term, and several links for current Supreme Court news and information. Both sections also feature a search engine. Additional resources at the site include a Town Hall section that explores Hot Topics (currently flag burning) and message boards on a wide variety of Constitutional issues.

  15. FindLaw Consumer Law Center

    NSDL National Science Digital Library

    One of the most comprehensive legal resources on the Internet, Findlaw (described in the February 23, 1996 Scout Report) has offerings for consumers. In the Consumer Law Center, users will find thousands of consumer-focused articles and resources in a number of different categories, such as Banking, Credit, Discrimination, Estate Planning, Family Law, Government Benefits, Health and Medicine, Intellectual Property, Investments, Labor & Employment, Personal Injury, Landlord/ Tenant & Real Estate, and many others. The Consumer Center also offers contact information for national consumer organizations, better business bureaus, corporations, trade associations and related organizations, as well as tips and guidance on filing effective consumer complaints. In addition, the site provides information on the process of hiring a lawyer and using lawyers to settle disputes or claims.

  16. Laws, Morals and Politics

    E-print Network

    Burkhardt, Robert J.

    for all three, and for others as well, 5 an absolute canon or criterion of morality as this enters the social sphere; call it Reason, Justice, the Law of Nature. All social norms, to be called law, must conform to this. While social norms may have...­ tinguishing an "internal point of view" on law which "sees the obligatoriness" of certain behaviors from an "external point of view" 2 5 which sees only patterns or regularities of conduct. Hart's approach follows the 38 post-Wittgensteinian tradition...

  17. The LSU Law Center -- Canada Bijuralism Conference. Introduction: Global Law and the Law School Curriculum.

    ERIC Educational Resources Information Center

    Costonis, John J.

    2002-01-01

    Introduces papers from a conference focused on the bijural programs of Louisiana State University Law Center and McGill University Faculty of Law. The programs educate all first-degree law students in both the common law and civil law traditions, preparing them for the increasing globalization of legal practice. (EV)

  18. Micro-mechanical modeling of perforating shock damage

    SciTech Connect

    Swift, R.P.; Krogh, K.E. [Los Alamos National Lab., NM (United States); Behrmann, L.A. [Schlumberger Perforating and Testing (United States); Halleck, P.M. [Pennsylvania State Univ., University Park, PA (United States)

    1997-11-17

    Shaped charge jet induced formation damage from perforation treatments hinders productivity. Manifestation of this damage is in the form of grain fragmentation resulting in fines that plug up pore throats along with the breakdown of inter-grain cementation. The authors use the Smooth Particle Hydrodynamic (SPH) computational method as a way to explicitly model, on a grain pore scale, the dynamic interactions of grains and grain/pores to calculate the damage resulting from perforation type stress wave loading. The SPH method is a continuum Lagrangian, meshless approach that features particles. Clusters of particles are used for each grain to provide representation of a grain pore structure that is similar to x-ray synchrotron microtomography images. Numerous damage models are available to portray fracture and fragmentation. In this paper the authors present the results of well defined impact loading on a grain pore structure that illustrate how the heterogeneity affects stress wave behavior and damage evolution. The SPH approach easily accommodates the coupling of multi-materials. Calculations for multi-material conditions with the pore space treated as a void, fluid filled, and/or clay filled show diverse effects on the stress wave propagation behavior and damage. SPH comparisons made with observed damage from recovered impacted sandstone samples in gas gun experiments show qualitatively the influence of stress intensity. The modeling approach presented here offers a unique way in concert with experiments to define a better understanding of formation damage resulting from perforation completion treatments.

  19. Damage Detection and Analysis in CFRPs Using Acoustic Emission Technique

    NASA Astrophysics Data System (ADS)

    Whitlow, Travis Laron

    Real time monitoring of damage is an important aspect of life management of critical structures. Acoustic emission (AE) techniques allow for measurement and assessment of damage in real time. Acoustic emission parameters such as signal amplitude and duration were monitored during the loading sequences. Criteria that can indicate the onset of critical damage to the structure were developed. Tracking the damage as it happens gives a better analysis of the failure evolution that will allow for a more accurate determination of structural life. The main challenge is distinguishing between legitimate damage signals and "false positives" which are unrelated to damage growth. Such false positives can be related to electrical noise, friction, or mechanical vibrations. This research focuses on monitoring signals of damage growth in carbon fiber reinforced polymers (CFRPs) and separating the relevant signals from the false ones. In this Dissertation, acoustic emission signals from CFRP specimens were experimentally recorded and analyzed. The objectives of this work are: (1) perform static and fatigue loading of CFRP composite specimens and measure the associated AE signals, (2) accurately determine the AE parameters (energy, frequency, duration, etc.) of signals generated during failure of such specimens, (3) use fiber optic sensors to monitor the strain distribution of the damage zone and relate these changes in strain measurements to AE data.

  20. Philadelphia University Faculty of law

    E-print Network

    Philadelphia University Faculty of law Department of -------------- ---------- semester, 2007/2008 Course Syllabus Course code: 410417 Course Title: Private International Law Course prerequisite (s) and Professor Dr. Sabri Thyabat Course module description: Module name: Private international law Prerequisite

  1. Beyond Unions, Notwithstanding Labor Law

    E-print Network

    Loudon, Catherine

    561 Beyond Unions, Notwithstanding Labor Law Marion Crain & Ken Matheny* Introduction .....................................................................................................................561 I. Labor Unionism and the Labor Law Frame IV. Implications of a Revived Right of Assembly for Labor Law..........................601

  2. What's Inside: Child Labor Laws

    E-print Network

    Veiga, Pedro Manuel Barbosa

    What's Inside: · Child Labor Laws · Attachments to Online Job Announcements · Hiring Officials child labor laws that apply. Below is a brief overview. 14 and 15 year olds: Departments must keep-year age groupmayworkatanytimeforunlimitedhoursinany non-hazardousposition. CHILD LABOR LAWS

  3. Modeling of mechanical damage detection in CFRPs via electrical resistance

    Microsoft Academic Search

    Z. H. Xia; W. A. Curtin

    2007-01-01

    Carbon fiber reinforced polymer composites (CFRPs) are inherently multifunctional materials that, in addition to their primary function as a structural material, allow for the sensing and monitoring of in situ damage nucleation and evolution by the measurement of the material electrical resistance. Here an analytic model is developed for the transverse (perpendicular to the fibers) electrical resistance of pristine and

  4. Damaged Hospital Wing

    USGS Multimedia Gallery

    This two story hospital wing in Cauquenes, Chile suffered severe damage to the wall of the first floor as a result of the M 8.8 earthquake on Feb. 27, 2010. This building must be torn down. All patients were successfully evacuated at 3:34 AM after the earthquake shaking started....

  5. Perinatal Brain Damage Causation

    Microsoft Academic Search

    Olaf Dammann; Alan Leviton

    2007-01-01

    The search for causes of perinatal brain damage needs a solid theoretical foundation. Current theory apparently does not offer a unanimously accepted view of what constitutes a cause, and how it can be identified. We discuss nine potential theoretical misconceptions: (1) too narrow a view of what is a cause (causal production vs. facilitation), (2) extrapolating from possibility to fact

  6. Earthquake Damage Slide Show

    NSDL National Science Digital Library

    This slide show presents examples of various types of damage caused by earthquakes. Photos include structural failures in bridges and buildings, landshifts, landslides, liquefaction, fires, tsunamis, and human impacts. Supplemental notes are provided to aid instructors about the photos presented on each slide.

  7. Coping with brain damage

    NASA Technical Reports Server (NTRS)

    Waring, W.

    1974-01-01

    Two neurological disorders, cerebral palsy, and traumatic brain damage as from an accident, are considered. The discussion covers the incidence of disabilities, their characteristics, and what is now being done to deal with them, particularly in reference to areas in which the capabilities of the engineer can be effectively applied.

  8. NonLocal Plastic-Damage Model for Failure Analysis of Sheet-Metals

    Microsoft Academic Search

    M. Brunet; F. Morestin; H. Walter-Leberre

    A new damage model which takes account of void shape effect and anisotropy of the matrix material is integrated into the dynamic\\u000a explicit finite element framework to predict the damage evolution which occurs under crash or stamping process. For the strain\\u000a localization and failure, the pathological mesh dependence has been overcome by a non-local approach where the evolution equation for

  9. Damage mechanics in engineering materials

    SciTech Connect

    Voyiadjis, G.Z. [ed.] [Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Civil and Environmental Engineering; Woody Ju, J.W. [ed.] [Univ. of California, Los Angeles, CA (United States). Dept. of Civil Engineering; Chaboche, J.L. [ed.] [ONERA, Resistance des Structures, Chatillon (France)

    1998-12-31

    This book contains thirty peer-reviewed papers that are based on the presentations made at the symposium on Damage Mechanics in Engineering Materials on the occasion of the Joint ASME/ASCE/SES Mechanics Conference (McNU97), held in Evanston, Illinois, June 28--July 2, 1997. The key area of discussion was on the constitutive modeling of damage mechanics in engineering materials encompassing the following topics: macromechanics/micromechanical constitutive modeling, experimental procedures, numerical modeling, inelastic behavior, interfaces, damage, fracture, failure, computational methods. The book is divided into six parts: study of damage mechanics; localization and damage; damage in brittle materials; damage in metals and metal matrix composites; computational aspects of damage models; damage in polymers and elastomers.

  10. Fusion leads to effective segregation of damage during cell division: An analytical treatment.

    PubMed

    Lade, Steven J; Coelho, Miguel; Toli?, Iva M; Gross, Thilo

    2015-08-01

    High levels of cellular damage are associated with impairment of cellular function and cell death. Partitioning the damage into a fraction of cells in the population improves population fitness and survival. We have previously shown that protein aggregates, resulting from misfolded, damaged proteins, fuse with each other leading to damage partitioning during cell division. Here, using an analytical treatment of aggregate fusion in dividing cells we present analytical expressions for two measures of damage partition: aggregate mass partition asymmetry between two dividing cells and standard deviation of total aggregate mass across the population. The scaling laws obtained demonstrate how damage partition may generally depend on characteristics of the cellular processes, facilitating better understanding of damage segregation in biological cells. PMID:25934351

  11. Understanding Evolution

    NSDL National Science Digital Library

    2004-02-06

    This site provides access to basic and advanced online resources for teaching the science and history of evolutionary biology. The resources are organized by topic: the mechanisms of evolution; the relevance of evolutionary theory to everyday life; lines of scientific evidence; and the history of ideas, research, and contributors in the study of evolution. For teachers, there are searchable databases of lesson plans, activities, and conceptual frameworks on the history of life, evidence for evolution, mechanisms of evolution, and the nature of science. Other materials include links to news items and highlighted features on specific evolution topics.

  12. Harris County Law Library 

    E-print Network

    Raiford Stripling Associates, Inc.; Stripling, Raiford L.

    2011-08-29

    A new method for optimizing heat exchangers is developed in this paper. It is based on second law efficiency relationships rather than on the traditional heat exchanger effectiveness concept. The cost of energy is based on its availability level...

  13. Potential Conservation Laws

    E-print Network

    Michael Kunzinger; Roman O. Popovych

    2008-04-15

    We prove that potential conservation laws have characteristics depending only on local variables if and only if they are induced by local conservation laws. Therefore, characteristics of pure potential conservation laws have to essentially depend on potential variables. This statement provides a significant generalization of results of the recent paper by Bluman, Cheviakov and Ivanova [J. Math. Phys., 2006, V.47, 113505]. Moreover, we present extensions to gauged potential systems, Abelian and general coverings and general foliated systems of differential equations. An example illustrating possible applications of proved statements is considered. A special version of the Hadamard lemma for fiber bundles and the notions of weighted jet spaces are proposed as new tools for the investigation of potential conservation laws.

  14. Matching Law Visualization Tool

    E-print Network

    Reed, Derek D.

    2015-05-15

    , the matching law remains an elusive principle to students of behavior analysis lacking requisite training in quantitative analyses. This simulation tool is intended to visually describe how manipulations of the parameters of the quantitative models modulate...

  15. Stokes' Law Revisited

    ERIC Educational Resources Information Center

    Wray, E. M.

    1977-01-01

    Discusses limitations and corrections to be made in physics experiments involving the investigations of drag and terminal velocity on spheres falling through a liquid in accordance with Stokes' law. (SL)

  16. Newton's Laws of Motion

    NSDL National Science Digital Library

    Dr. David P. Stern

    2004-10-09

    This series of web pages, part of From Stargazers to Starships, describes Newton's three laws of motion and the two concepts on which they are based, force and inertia. A lesson plan for instructors is also provided.

  17. Law Hall & Council 

    E-print Network

    Unknown

    2011-08-17

    Slowly but surely the direct application of the Second Law of Thermodynamics is being recognized, for its practical usefulness in engineering. This paper will describe the methods, and show the results of applications to whole economic sectors...

  18. AJ Ohm's Law Calculator

    NSDL National Science Digital Library

    Jimmy Raymond

    The electrical relationships between resistance (R), current (I), power (P) and voltage (E) is defined by Ohm's Law. One ohm is defined as the resistance which allow the current of one ampere under a potential difference of 1 volt.

  19. Business Law Today

    NSDL National Science Digital Library

    The American Bar Association has recently begun to provide full text of this bimonthly magazine covering various aspects of business law. In addition to feature articles, there are five small sections with snippets of legal news and features.

  20. Ohm's Law I

    NSDL National Science Digital Library

    2014-09-18

    Students work to increase the intensity of a light bulb by testing batteries in series and parallel circuits. They learn about Ohm's law, power, parallel and series circuits, and ways to measure voltage and current.

  1. The Abortion Law Homepage

    NSDL National Science Digital Library

    This privately posted page offers extensive and highly credible information on legislation and jurisprudence relating to abortion in the US. The site offers thoroughly linked discussions of constitutional law, Roe v. Wade, Planned Parenthood v. Casey, state and federal abortion laws, including partial-birth abortion laws, and much more. The hypertext links are to primary documents including court decisions, texts of legislation, court briefs, and oral argument transcripts. There is also an index to primary documents for ease of access. We found the page to have no political agenda. As the author states, "this page is being constructed to help people, regardless of their political bent, understand the background and state of abortion law in America, and access related legal material--especially that which is less available and less well known."

  2. Potential conservation laws

    SciTech Connect

    Kunzinger, Michael [Fakultaet fuer Mathematik, Universitaet Wien, Nordbergstrasse 15, A-1090 Wien (Austria); Popovych, Roman O. [Fakultaet fuer Mathematik, Universitaet Wien, Nordbergstrasse 15, A-1090 Wien (Austria); Institute of Mathematics, NAS of Ukraine, 3 Tereshchenkivska Str., Kyiv-4 (Ukraine)

    2008-10-15

    We prove that potential conservation laws have characteristics depending only on local variables if and only if they are induced by local conservation laws. Therefore, characteristics of pure potential conservation laws have to essentially depend on potential variables. This statement provides a significant generalization of results of the recent paper by Bluman et al. [J. Math. Phys. 47, 113505 (2006)]. Moreover, we present extensions to gauged potential systems, Abelian and general coverings, and general foliated systems of differential equations. An example illustrating possible applications of these results is given. A special version of the Hadamard lemma for fiber bundles and the notions of weighted jet spaces are proposed as new tools for the investigation of potential conservation laws.

  3. Law Enforcement Technology

    NSDL National Science Digital Library

    Serving as a sworn officer of the law continues to be one of the most demanding professions in the country, and those in the field will certainly appreciate the website of Law Enforcement Technology. This monthly magazine concentrates primarily on the emerging trends in the field of law enforcement technology, such as the use of computers, refined body armor designs, and of course, improvements in weaponry and forensics. On their website, visitors can read articles about new data management systems, mobile license plate readers, and innovative flashlights. Along with these feature articles, each issue contains information about funding opportunities for law enforcement technology initiatives and new developments in software technology. Finally, visitors can also sign up to receive email notifications about job opportunities and promotional offers.

  4. Numerical study of damage in unsaturated Geological and Engineered barriers

    NASA Astrophysics Data System (ADS)

    Arson, C.; Gatmiri, B.

    The theoretical framework of a damage model dedicated to non-isothermal unsaturated porous media is presented. The damage variable is a second-order tensor, and the model is formulated in independent state variables. The behavior laws are derived from a postulated expression of Helmholtz free energy. The damaged rigidities are computed by applying the Principle of Equivalent Elastic Energy (PEEE). Internal length parameters are introduced in the expressions of liquid water and vapor conductivities, to account for cracking effects on fluid flows. The damage model has been implemented in ?-Stock Finite Element program. The mechanical aspect of the damage model is validated by simulating a triaxial compression test on a dry isothermal brittle material. Then, a sophisticated model of nuclear waste disposal, involving two non-isothermal unsaturated porous media, is reproduced. The results obtained in elasticity are in good agreement with the results presented in the corresponding reference article. A parametric study on initial damage is then performed to assess the influence of the Excavated Damaged Zone (EDZ) on the response of the nuclear waste repository during the heating phase. The trends meet the theoretical expectations.

  5. Laser induced damage in optical materials: 7th ASTM symposium.

    PubMed

    Glass, A J; Guenther, A H

    1976-06-01

    The Seventh ERDA-ASTM-ONR-NBS Symposium on Laser Induced Damage in Optical Materials was held at the National Bureau of Standards in Boulder, Colorado, on 29-31 July 1975. These Symposia are held as part of the activities in ASTM Subcommittee II on Lasers and Laser Materials, which is charged with the responsibilities of formulating standards and test procedures for laser materials, components, and devices. The Chairman of Subcommittee II is Haynes Lee, of Owens-Illinois, Inc. Co-chairmen for the Damage Symposia are Arthur Guenther of the Air Force Weapons Laboratory and Alexander J. Glass of Law-rence Livermore Laboratory. Over 150 attendees at the Symposium heard forty-five papers on topics relating fabrication procedures to laser induced damage in optical materials; on metal mirrors; in ir window materials; the multipulse, wavelength, and pulse length dependence of damage thresholds; damage in dielectric films and at exposed surfaces; as well as theoretical discussions on avalanche ionization and multiphoton processes of importance at shorter wavelengths. Of particular importance were the scaling relations developed from several parametric studies relating fundamental properties (refractive index, surface roughness etc.) to the damage threshold. This year many of the extrinsic influences tending to reduce a materials damage resistance were isolated such that measures of their egregious nature could be quantified. Much still needs to be accomplished to improve processing and fabrication procedures to allow a measurable approach to a materials intrinsic strength to be demonstrated. PMID:20165214

  6. Power-laws and Non-Power-laws in Dark Matter Halos

    E-print Network

    R. N. Henriksen

    2006-09-05

    Simulated dark matter profiles are often modelled as a `NFW' density profile rather than a single power law. Recently, attention has turned to the rather rigorous power-law behaviour exhibited by the `pseudo phase-space density' of the dark matter halo, which is defined dimensionally in terms of the local density and velocity dispersion of the dark matter particles. The non-power-law behaviour of the density profile is generally taken to exclude simple scale-free, in-fall models; however the power-law behaviour of the `pseudo-density' is a counter indication. We argue in this paper that both behaviours may be at least qualitatively understood in terms of a dynamically evolving self-similarity, rather than the form for self-similar infall that is fixed by cosmological initial conditions. The evolution is likely due to collective relaxation such as that provided by the radial-orbit instability on large scales. We deduce, from a distribution function given by first order coarse-graining, both the NFW-type density profile and the power-law pseudo-density profile. The results are not greatly sensitive to variation about 3 in the power of the velocity dispersion used in the definition of the phase space pseudo-density. We suggest that the power 2 may create the more physical quantity, whose deviations from a power-law are a diagnostic of incomplete relaxation.

  7. Law & Politics Internet guide

    NSDL National Science Digital Library

    This metasite of law and political resources is designed for legal professionals, academics, and the general public. About two dozen lists of annotated links cover topics such as Legal Portals, Legal Resources, Foreign & International Law, and Legal Research. Equipped with language translation software (which works well on some pages but seems to cause graphics problems on other pages), the site is well designed and easy to use.

  8. Damage monitoring of refractory wall in a generic entrained-bed slagging gasification system

    E-print Network

    Ray, Asok

    INTRODUCTION Modern day gasification plants offer a versatile and clean way to convert coal and other791 Damage monitoring of refractory wall in a generic entrained-bed slagging gasification system-bed slagging gasification systems is attributed to evolution of structural damage in the refractory walls

  9. Structural Properties and Deformation Patterns of Evolving Strike-slip Faults: Numerical Simulations Incorporating Damage Rheology

    E-print Network

    Lyakhovsky, Vladimir

    . This broader domain corresponds to shallow damage (or compliant) zones which have been identified in several words: Damage rheology, fault zone structure, strike-slip fault evolution, compliant zones, fault stepovers. 1. Introduction Understanding the geometrical and mechanical properties of fault zones

  10. Generalized second law of thermodynamics in warped DGP braneworld

    E-print Network

    Ahmad Sheykhi; Bin Wang

    2009-11-16

    We investigate the validity of the generalized second law of thermodynamics on the $(n-1)$-dimensional brane embedded in the $(n+1)$-dimensional bulk. We examine the evolution of the apparent horizon entropy extracted through relation between gravitational equation and the first law of thermodynamics together with the matter field entropy inside the apparent horizon. We find that the apparent horizon entropy extracted through connection between gravity and the first law of thermodynamics satisfies the generalized second law of thermodynamics. This result holds regardless of whether there is the intrinsic curvature term on the brane or a cosmological constant in the bulk. The observed satisfaction of the generalized second law provides further support on the thermodynamical interpretation of gravity based on the profound connection between gravity and thermodynamics.

  11. Fatigue damage initiation and growth from artificial defects in Zr-based metallic glass

    Microsoft Academic Search

    B. C. Menzel; R. H. Dauskardt

    2008-01-01

    An array of well-defined and micrometer-sized circular and line defects were produced on the surface of Zr-based bulk metallic glass bend specimens using a focused ion beam (FIB) in order to study the effect of the defect size, orientation and shape on fatigue damage initiation and growth. Damage evolution was recorded using a surface-replicating technique. Damage was observed to initiate

  12. Implantation of si under extreme conditions: The effects of high temperature and dose on damage accumulation

    Microsoft Academic Search

    O. W. Holland; Ling Xie; Bent Nielsen; D. S. Zhou

    1996-01-01

    The accumulation of lattice damage in Si(100) during ion irradiation at extreme dose and temperature was investigated. Irradiation\\u000a above the ion-induced, crystal-to-amorphous transition temperature (?200°C) enabled damage growth to be studied to arbitrarily\\u000a high dose. Electron microscopy and Rutherford backscattering spectrometry were used to characterize the growth of damage under\\u000a these extreme conditions, as well as its microstructural evolution. These

  13. Theoretical and experimental investigation of anisotropic damage in textile-reinforced composite structures

    Microsoft Academic Search

    W. Hufenbach; R. Böhm; L. Kroll; A. Langkamp

    2004-01-01

    In the present work, a phenomenological plane-stress damage-mechanics-based model for textile-reinforced composites is presented and its predictive capability is evaluated by carrying out a series of experimental tests. Damage variables are introduced to describe the evolution of the damage state and, as a subsequence, the degradation of material stiffness. For calculating the nonlinear stress and strain distribution of complexly loaded

  14. Nondestructive damage detection and evaluation technique for seismically damaged structures

    NASA Astrophysics Data System (ADS)

    Adachi, Yukio; Unjoh, Shigeki; Kondoh, Masuo; Ohsumi, Michio

    1999-02-01

    The development of quantitative damage detection and evaluation technique, and damage detection technique for invisible damages of structures are required according to the lessons from the 1995 Hyogo-ken Nanbu earthquake. In this study, two quantitative damage sensing techniques for highway bridge structures are proposed. One method is to measure the change of vibration characteristics of the bridge structure. According to the damage detection test for damaged bridge column by shaking table test, this method can successfully detect the vibration characteristic change caused by damage progress due to increment excitations. The other method is to use self-diagnosis intelligent materials. According to the reinforced concrete beam specimen test, the second method can detect the damage by rupture of intelligent sensors, such as optical fiber or carbon fiber reinforced plastic rod.

  15. Hyperbolic Conservation Laws The 1D conservation law

    E-print Network

    Gardner, Carl

    Hyperbolic Conservation Laws The 1D conservation law wt + f(w)x = 0 (where w and f have m of linearly independent eigenvectors). Then solutions to the conservation law can be viewed in terms to form a complete linearly independent set, and the conservation law is called strictly hyperbolic

  16. The Law of Hazardous Waste: CERCLA, RCRA, & Common Law Claims

    E-print Network

    Kammen, Daniel M.

    Law 273.4 The Law of Hazardous Waste: CERCLA, RCRA, & Common Law Claims (Fall 2008) Units: 3 CCN (2 to RCRA, CERCLA, and the Administrative Process Sec. A - Introduction Sec. B ­ Overview of RCRA and CERCLA The Law of Hazardous Waste Disposal and Remediation 2. Ch. III, Intro to RCRA, CERCLA

  17. The Law of Hazardous Waste: CERCLA, RCRA, & Common Law Claims

    E-print Network

    Kammen, Daniel M.

    Law 273.4 The Law of Hazardous Waste: CERCLA, RCRA, & Common Law Claims (Fall 2006) Units: 3 CCN (2: 1. Miller & Johnston The Law of Hazardous Waste Disposal and Remediation 2. Ch. III, Intro to RCRA, CERCLA, and the Administrative Process Sec. A - Introduction Sec. B ­ Overview of RCRA and CERCLA M: 39

  18. Damage mechanics characterization on fatigue behavior of a solder joint material

    SciTech Connect

    Chow, C.L.; Yang, F. [Univ. of Michigan, Dearborn, MI (United States). Dept. of Mechanical Engineering; Fang, H.E. [Sandia National Labs., Albuquerque, NM (United States). Computational Physics Dept.

    1998-08-01

    This paper presents the first part of a comprehensive mechanics approach capable of predicting the integrity and reliability of solder joint material under fatigue loading without viscoplastic damage considerations. A separate report will be made to present a comprehensive damage model describing life prediction of the solder material under thermomechanical fatigue loading. The method is based on a theory of damage mechanics which makes possible a macroscopic description of the successive material deterioration caused by the presence of microcracks/voids in engineering materials. A damage mechanics model based on the thermodynamic theory of irreversible processes with internal state variables is proposed and used to provide a unified approach in characterizing the cyclic behavior of a typical solder material. With the introduction of a damage effect tensor, the constitutive equations are derived to enable the formulation of a fatigue damage dissipative potential function and a fatigue damage criterion. The fatigue evolution is subsequently developed based on the hypothesis that the overall damage is induced by the accumulation of fatigue and plastic damage. This damage mechanics approach offers a systematic and versatile means that is effective in modeling the entire process of material failure ranging from damage initiation and propagation leading eventually to macro-crack initiation and growth. As the model takes into account the load history effect and the interaction between plasticity damage and fatigue damage, with the aid of a modified general purpose finite element program, the method can readily be applied to estimate the fatigue life of solder joints under different loading conditions.

  19. Optimisation of Quantum Evolution Algorithms

    E-print Network

    Apoorva Patel

    2015-03-04

    Given a quantum Hamiltonian and its evolution time, the corresponding unitary evolution operator can be constructed in many different ways, corresponding to different trajectories between the desired end-points. A choice among these trajectories can then be made to obtain the best computational complexity and control over errors. As an explicit example, Grover's quantum search algorithm is described as a Hamiltonian evolution problem. It is shown that the computational complexity has a power-law dependence on error when a straightforward Lie-Trotter discretisation formula is used, and it becomes logarithmic in error when reflection operators are used. The exponential change in error control is striking, and can be used to improve many importance sampling methods. The key concept is to make the evolution steps as large as possible while obeying the constraints of the problem. In particular, we can understand why overrelaxation algorithms are superior to small step size algorithms.

  20. Quantification of fretting damage

    Microsoft Academic Search

    Siegfried Fouvry; Philippe Kapsa; Leo Vincent

    1996-01-01

    The fretting behaviour of high speed steel SC 6-5-2 uncoated and coated with a TiN coating against an alumina ball was studied based on a fretting map approach.Cracking and material loss were observed depending on the contract loading. To quantify the damage, a methodology is proposed based on an elastic Hertzian-Mindlin contact description. The sliding regimes are clearly defined, applying

  1. Tornado damage risk assessment

    SciTech Connect

    Reinhold, T.A.; Ellingwood, B.

    1982-09-01

    Several proposed models were evaluated for predicting tornado wind speed probabilities at nuclear plant sites as part of a program to develop statistical data on tornadoes needed for probability-based load combination analysis. A unified model was developed which synthesized the desired aspects of tornado occurrence and damage potential. The sensitivity of wind speed probability estimates to various tornado modeling assumptions are examined, and the probability distributions of tornado wind speed that are needed for load combination studies are presented.

  2. Photochemical Damage of the Retina

    Microsoft Academic Search

    Jiangmei Wu; Stefan Seregard; Peep V. Algvere

    2006-01-01

    Visual perception occurs when radiation with a wavelength between 400 and 760 nm reaches the retina. The retina has evolved to capture photons efficiently and initiate visual transduction. The retina, however, is vulnerable to damage by light, a vulnerability that has long been recognized. Photochemical damage has been widely studied, because it can cause retinal damage within the intensity range

  3. Philadelphia University Faculty of Law

    E-print Network

    Philadelphia University Faculty of Law Foreign Students Handbook 2005/2006 #12;The Faculty of Law University 4 International Cooperation 5 The Map of The University 6 The Faculty of Law in a glimpse 7 Mission of the Faculty 8 Learning & Teaching System 9 Admission's Requirement 11 The Law Program 15

  4. Assisted Reproduction in Jewish Law

    Microsoft Academic Search

    Daniel B. Sinclair

    2002-01-01

    This Article attempts to untangle Jewish law regarding assisted reproductive technologies (ARTs), namely artificial insemination with husband's sperm, artificial insemination with donor sperm, and in vitro fertilization. The author examines teachings by prominent Jewish law scholars and clarifies basic schools of thought regarding each method. He explores Jewish law prohibitions on incest and adultery and the laws regarding legal parentage

  5. Symposium Issue Reimagining Labor Law

    E-print Network

    Loudon, Catherine

    i Symposium Issue Reimagining Labor Law FOREWORD Reimagining Collective Rights in the Workplace Direction for Worker Protection? Chris Tilly & Marie Kennedy 539 Beyond Unions, Notwithstanding Labor Law Marion Crain & Ken Matheny 561 Not Dead Yet: Preserving Labor Law Strengths While Exploring New Labor Law

  6. Undergraduate Handbook School of Law

    E-print Network

    Hickman, Mark

    Undergraduate Handbook School of Law Critique. LLB 2014LAW #12;Contents 1 From the Dean Welcome has been taken to ensure the information contained in this School of Law Undergraduate Handbook of Canterbury Calendar is definitive. School of Law Undergraduate Handbook published March 2014. 6 LLB

  7. Water laws and concepts

    USGS Publications Warehouse

    Thomas, H.E.

    1970-01-01

    Throughout human history various laws and customs have developed concerning the individual rights and rights in common to the waters of the earth. Many existing laws and concepts are clearly influenced by the environment in which they originated and reflect the relative abundance or scarcity of water. Many concepts reflect the people's original interests in the water and once established have been passed from generation to generation with little modification. Some laws and concepts have been carried by people in their migrations and colonial expansions to vastly different environments, with rather curious consequences. In many places water laws that had been well adapted to the natural environment have become less tenable because of man's activities in modifying that environment, or because of increasing use of water: Increasing consumptive use shifts the water economy toward lesser abundance or increasing deficiency; increasing nonconsumptive use results in pollution of the water resources, so that they become less suitable for other users. The water-rights systems in the United States vary from State to State: some are reasonably fitted to their environment, some have outlived their place in history, some are wasteful of water, some show favoritism to certain special interests or segments of the population. Water-use rights are universally recognized as real property, with constitutional protection against deprivation without due process of law.

  8. Military Law Review

    NSDL National Science Digital Library

    The Library of Congress' Research Center of Military Legal Resources contains, among other publications, the Military Law Review. The Military Law Review has been published quarterly since 1958, and is meant to be used by military attorneys in their work and "'provides a forum for those interested in military law to share the products of their experience and research.'" Visitors should also note that most of the issues from 1958 to 2008 are available for general perusal. Each issue of the journal contains both articles and book reviews. An article in the Winter 2008 issue, entitled "Crossing the Line: Reconciling the Right to Picket Military Funerals With the First Amendment", is a very accessible article about the constitutionality of state and federal funeral picketing laws. Visitors interested in learning about the school that provides military legal education, and where the Military Law Review is published, should click on the link "The Judge Advocate General's Legal Center & School (JAGS), U.S. Army, Charlottesville, Virginia", in the first paragraph on the homepage

  9. Understanding Evolution

    NSDL National Science Digital Library

    The intent of this website is to give teachers a background understanding of evolution, opening the door by giving them strategies for teaching and responding to misconceptions and roadblocks. The heart of the site is Evolution 101, which can serve as a primer to evolutionary theory or an intensive course in the nitty gritty details of speciation, micro- and macroevolution, and ongoing research into how evolution happens. The site is replete with practical examples of how evolution impacts our daily lives, including lesson plans about bunny breeding, the problem of antibiotic resistance in disease organisms, and the conservation and breeding of endangered species.

  10. Time-dependent damage in predictions of fatigue behaviour of normal and healing ligaments

    NASA Astrophysics Data System (ADS)

    Thornton, Gail M.; Bailey, Soraya J.; Schwab, Timothy D.

    2015-06-01

    Ligaments are dense fibrous tissues that connect bones across a joint and are exposed daily to creep and fatigue loading. Ligaments are tensile load-bearing tissues; therefore, fatigue loading will have a component of time-dependent damage from the non-zero mean stress and cycle-dependent damage from the oscillating stress. If time-dependent damage is not sufficient to completely predict the fatigue response, then cycle-dependent damage could be an important contributor. Using data from normal ligaments (current study and Thornton et al., Clin. Biomech. 22:932-940, 2007a) and healing ligaments (Thornton and Bailey, J. Biomech. Eng. 135:091004-1-091004-6, 2013), creep data was used to predict the fatigue response considering time-dependent damage. Relationships between creep lifetime and test stress or initial strain were modelled using exponential or power-law regression. In order to predict fatigue lifetimes, constant rates of damage were assumed and time-varying stresses were introduced into the expressions for time-dependent damage from creep. Then, the predictions of fatigue lifetime were compared with curvefits to the fatigue data where exponential or power-law regressions were used to determine the relationship between fatigue lifetime and test stress or initial strain. The fatigue prediction based on time-dependent damage alone greatly overestimated fatigue lifetime suggesting that time-dependent damage alone cannot account for all of the damage accumulated during fatigue and that cycle-dependent damage has an important role. At lower stress and strain, time-dependent damage was a greater relative contributor for normal ligaments than healing ligaments; however, cycle-dependent damage was a greater relative contributor with incremental increases in stress or strain for normal ligaments than healing ligaments.

  11. Punctuated equilibrium in software evolution

    NASA Astrophysics Data System (ADS)

    Gorshenev, A. A.; Pis'Mak, Yu. M.

    2004-12-01

    An approach based on the paradigm of self-organized criticality is proposed for experimental investigation and theoretical modeling of software evolution. The dynamics of modifications is studied for three free, open source programs MOZILLA, FREE-BSD, and EMACS using the data from version control systems. Scaling laws typical for self-organized criticality found. A model of software evolution presenting the natural selection principle is proposed. Results of numerical and analytical investigation of the model are presented. They are in good agreement with data collected for real-world software.

  12. Student Press Law Center

    NSDL National Science Digital Library

    Created in 1974, the Student Press Law Center (SPLC) is the â??nation's only legal assistance agency devoted exclusively to educating high school and college journalists about the rights and responsibilities embodied in the First Amendment.â?ť Based in Arlington, Virginia the Center provides free legal advice and information along with low-cost educational materials. On its homepage, visitors can make their way through sections that include Know Your Rights and Classroom Resources. In Know Your Rights, visitors can learn about the rights of high school journalists and educators, peruse an online law library, and check out an interactive map tracking the latest legal developments in student press rights nationally. Moving on, the Classroom Resources area brings together dozens of classroom handouts, presentations, and some fun short quizzes regarding libel, privacy, and other media-law issues.

  13. Newton's Third Law

    NSDL National Science Digital Library

    This educational wallsheet illustrating Newton's Third Law of Motion is the third of a set of four. Each image on the front of the poster illustrates Newton's Third Law, and is described on the back. The wallsheet also provides teachers with background information, pre-activity reading for the students that relates the law to the action of the fuel being expelled from the rocket and its reaction on the rocket carrying the Swift satellite into orbit, as well as Swift's turning motions once in orbit, pre-activity discussion with optional questions that relate to the Swift satellite, a classroom-ready activity and assessment, and post-activity discussions that tie the classroom activity back to the Swift satellite.

  14. Federal Communications Law Journal

    NSDL National Science Digital Library

    There's a whole lot of material to cover within the world of communications law, and within their aegis, the Federal Communications Law Journal (FCLJ) covers everything from intellectual property to cable regulation. The Journal is published by Indiana University law students, and it also serves as the official journal for the Federal Communications Bar Association. This status also means that the Journal will occasionally feature pieces by members of Congress and commissioners in the Federal Communications Commission. First-time visitors to the site can browse through the contents of the most recent issues, or they can browse through archived issues all the way back to 1993. Also, visitors can view some of their short commentaries in the "Forum" area and learn about print subscriptions and submitting manuscripts for consideration.

  15. Physical Laws for Mechanobiology

    NASA Technical Reports Server (NTRS)

    Freed, Alan D.

    2007-01-01

    Higher-level physical laws applicable to biological tissues are presented that will permit the modeling of metabolic activity at the cellular level, including variations in the mass of a tissue. Here the tissue is represented as a fluid/solid mixture, wherein molecular solutes transport within the fluid, and cells can migrate throughout the porous solid. Variations in mass can arise via exchanges in mass between the constituent phases within a control volume such that mass is conserved in the tissue overall. The governing balance laws for mass, momentum, energy, and entropy are a special case of those describing a chemically reacting mixture with diffusion. Thermodynamic constraints on the constitutive structure are addressed. Biophysics; Biomechanics; Brownian motion; Cell migration; Mixture theory; Thermodynamic laws; Tissue mechanics

  16. A New Damage Constitutive Model for Thermal Deformation of AA6111 Sheet

    NASA Astrophysics Data System (ADS)

    Ma, Wenyu; Wang, Baoyu; Bian, Jianhua; Tang, Xuefeng; Yang, Lei; Huo, Yuanming

    2015-06-01

    Hot tensile tests were conducted using a Gleeble 1500, at the temperature range of 623 K to 823 K (350 °C to 550 °C) and strain rate range of 0.1 to 10 s-1. Flow stress is significantly affected by temperature and strain rate. As strain increases; the flow stress first rapidly increases, subsequently maintains a steady state, and finally drops sharply because of damage evolution. The features and mechanism of the damage were studied utilizing a scanning electron microscope. Micro-void nucleation, growth, and coalescence result in the failure of the hot-formed specimen. A damage equation based on continuum damage mechanics and damage mechanism in hot metal forming was proposed. A unified viscoplastic damage model coupled with strain, strain rate, temperature, dislocation, hardening, damage, damage rate, and so on was developed and calibrated for AA6111 using Genetic Algorism Tool in three steps. This model can be used to describe viscoplastic flow behavior and damage evolution at various temperatures and strain rates. The model was implemented into the finite element (FE) model in ABAQUS platform via the variable user material subroutine. Thus, the FE model could be employed to study the damage distribution and the effects of blank holder force (BHF) and forming velocity on hot cylindrical deep drawing. It is revealed that lower BHF and higher velocity are beneficial for drawability. A good agreement between simulated and experimental results has been achieved.

  17. Viscoelastic{Viscoplastic Damage Model for Asphalt Concrete

    E-print Network

    Graham, Michael A.

    2010-10-12

    subroutine UMAT. Results from nite element simulations in Abaqus are presented. All values in this section are e ective values because this section presents the model for the undamaged material. The superimposed bars ( ) will be suppressed throughout... in the commercial nite element package Abaqus. Guidelines 13 for this implementation are provided by Huang (2008). The mechanical and moisture damage laws will likewise be discretized and the undamaged material model implementation will be modi ed to include...

  18. Generalized second law of thermodynamics in Gauss–Bonnet braneworld

    Microsoft Academic Search

    Ahmad Sheykhi; Bin Wang

    2009-01-01

    We investigate the validity the generalized second law of thermodynamics in a general braneworld model with curvature correction terms on the brane and in the bulk, respectively. Employing the derived entropy expression associated with the apparent horizon, we examine the time evolution of the total entropy, including the derived entropy of the apparent horizon and the entropy of the matter

  19. Long simulations of the Solar System: Brouwer's Law and Chaos

    E-print Network

    Sharp, Philip

    Long simulations of the Solar System: Brouwer's Law and Chaos K. R. Grazier W. I. Newman James M of motion for self- gravitating systems, particularly in the context of our Solar System's evolution growth can be attained in 3-D Solar System integrations. Our integrations are such that the positions

  20. Thermal annealing of radiation damaged titanite

    SciTech Connect

    Chrosch, J.; Colombo, M.; Malcherek, T.; Salje, E.K.H. [Univ. of Cambridge (United Kingdom). Dept. of Earth Sciences; Groat, L.A. [Univ. of British Columbia, Vancouver (Canada). Dept. of Earth and Ocean Sciences; Bismayer, U. [Univ. Hamburg (Germany). Mineralogisch-Petrographisches Inst.

    1998-09-01

    Radiogenic impurities of 400 to 800 ppm U and Th in titanite, CaTiSiO{sub 5}, lead to moderate radiation damage ({approx}1.5 {times} 10{sup 18} {alpha}-decay events/g) and therefore to partial amorphization ({approx}30%). Powder X-ray diffraction on such damaged titanite from the Cardiff locality in Canada shows that two modifications of the crystalline material coexist. Both modifications are structurally {beta} phase but differ systematically in their lattice parameters and also in their chemical composition. One modification exhibits strong particle size broadening in X-ray diffraction patterns, whereas it is almost unstrained with respect to fully annealed titanite. The other modification shows large strain broadening and increased specific volume (about 3%) due to a high concentration of defects. The unstrained modification consists of small nucleation centers in the damaged material, and it grows when the sample is annealed. At annealing temperatures above 823 K, this modification dominates rapidly and replaces the strained titanite. The results of Rietveld refinement of the annealed samples and of the time evolution of isothermal annealing studies are discussed. The analysis of volume strain and of structural strain resulting from the peak profiles suggests a temperature-dependent activation energy for the recrystallization process, with E{sub A} {approx} 380 kJ/mol at T > 873 K and E{sub A} {approx} 500 kJ/mol at temperatures 773 K < T < 873 K.

  1. Kepler's Second Law

    NSDL National Science Digital Library

    David Stern

    This lesson introduces students to Kepler's second law; that planets (and satellites) move fastest at their closest approach to the center of attraction and slow down when far away. This is made evident by calculating the ratio of greatest and smallest orbital velocities and by invoking the concept of energy. Students should acquire an intuitive understanding for the way orbital velocities vary along each orbit according to Kepler's second law. They will review the concepts of potential energy and kinetic energy and understand that orbital motion also conserves energy, in a somewhat similar way, although the formulas look different. Students will also be introduced to the procedure for calculating orbital motion.

  2. Teaching Evolution

    ERIC Educational Resources Information Center

    Bryner, Jeanna

    2005-01-01

    Eighty years after the famous 1925 Scopes "monkey trial," which tested a teacher's right to discuss the theory of evolution in the classroom, evolution--and its most recent counterview, called "intelligent design"--are in the headlines again, and just about everyone seems to have an opinion. This past July, President Bush weighed in, telling…

  3. Time evolution of negative binomial optical field in diffusion channel

    E-print Network

    Liu Tang-Kun; Wu Pan-Pan; Shan Chuan-Jia; Liu Ji-Bing; Fan Hong-Yi

    2015-04-17

    We find time evolution law of negative binomial optical field in diffusion channel. We reveal that by adjusting the diffusion parameter, photon number can controlled. Therefore, the diffusion process can be considered a quantum controlling scheme through photon addition.

  4. Pennsylvania environmental law handbook

    SciTech Connect

    Not Available

    1990-01-01

    This book presents an analysis of business' obligations in chapters on: Air pollution control; Water pollution control; Coastal zone management and water obstructions; Wetlands; Solid and hazardous waste management; Waste minimization and pollution prevention; Right-to-know and emergency planning; Regulation of PCBs; Asbestos; Pennsylvania environmental Tort law; and Environmental considerations in business transactions.

  5. Stoke's Law Problem Set

    NSDL National Science Digital Library

    Rachel Headley

    This is a problem set that involves the calculation of velocities from a Reynolds number, determination of Stoke's Law applicability, and calculation of settling velocities for a variety of grain sizes and materials. This can be used in conjunction with a lab but is itself just a problem set.

  6. Law in Outer Space.

    ERIC Educational Resources Information Center

    Schmidt, William G.

    1997-01-01

    Provides an overview of the current practice and fascinating future of legal issues involved in outer space exploration and colonization. Current space law, by necessity, addresses broad principles rather than specific incidents. Nonetheless, it covers a variety of issues including commercial development, rescue agreements, object registration,…

  7. Equal Justice Under Law.

    ERIC Educational Resources Information Center

    Johnson, Earl, Jr., Ed.

    1994-01-01

    This special theme issue of "Update on Law-Related Education""tells about the past, present, and future of equal legal representation for all in our society." It is dedicated to the history and heroes of legal aid for the poor and the need to further that cause if the United States hopes to achieve equal justice for all. In his foreword, Justice…

  8. Relativistic Kepler's third law

    Microsoft Academic Search

    B. M. Barker; G. G. Byrd; R. F. Oconnell

    1986-01-01

    The authors give a post-Newtonian generalization of Kepler's third law that includes spin and quadrupole moment effects, parameterized post-Newtonian parameters gamma and beta, and the Nordtvedt effect. The time from periastron to apastron is also found, and it turns out, in general, not to be equal to half the period. The results are given in a very general coordinate system

  9. Kepler's third law

    Microsoft Academic Search

    A. Tan; W. L. Chameides

    1981-01-01

    There are slight differences in the standards of Kepler's third law in the different textbooks. The authors work out an average r, that over the arc lengths of the orbit and show that such an average is equal to the semimajor axis.(AIP)

  10. When is cloning lawful?

    Microsoft Academic Search

    Margaret Brumby; Pascal Kasimba

    1987-01-01

    The infertility (Medical Procedures) Act (Victoria) is the first legislation in the common-law world designed to regulate the practice of in vitro fertilization. This act explicitly prohibits “cloning,” without providing a definition of this term. The legislative history of the act suggests that it refers only to the production of multiple, identical copies of human individuals. But other scientific procedures,

  11. THE INVERSE CARE LAW

    Microsoft Academic Search

    JULIAN TUDOR HART

    care tends to vary inversely with the need for it in the population served. This inverse care law operates more completely where medical care is most exposed to market forces, and less so where such exposure is reduced. The market distribution of medical care is a primitive and historically outdated social form, and any return to it would further exag-

  12. Women's Law Initiative

    NSDL National Science Digital Library

    Women'sLaw.org was founded in February 2000 by attorneys, educators, advocates, and web designers, with the aim of using the internet to facilitate help for survivors of domestic violence and sexual assault. The language of the website is written in an accessible style, which is most welcome. The menu tab called "Know the Law", across the top of any page, has information available under state, federal, tribal, and religious law, and addresses common issues like "parental kidnapping", "restraining orders", "divorce", and "suing your abuser", in a question-and-answer format. Helpfully, the text of the laws of each state that aid or effect domestic abuse survivors can be found on this site, under the "Legal Statutes" tab, at the far right hand side of the menu across the top of any page. "State Statutes", "Federal Statutes", and "Tribal Statutes" are available. The "Helping Others" tab offers information on such groups as "Lawyers", "Doctors and Healthcare Workers", "Religious Leaders", and "Salon Professionals". The last group may come as a surprise, but visitors can read an article entitled "Enlisting the Aid of Hairstylists as Sentinels for Domestic Abuse", to learn about CUT IT OUT, which teaches salon professionals to recognize abuse in their clients.

  13. Mixed mode cohesive law

    Microsoft Academic Search

    J. L. Högberg

    2006-01-01

    A traction-separation relation to model the fracture process is presented. The cohesive law captures the linear elastic and softening behaviour prior to fracture. It also allows for different fracture parameters, such as fracture energy, strength and critical separation in different mode mixities. Thus, the fracture process in mode I (peel), in mode II (shear) or in mixed mode (a combination

  14. CONTRACT LAW: GENERAL THEORIES

    Microsoft Academic Search

    Richard Craswell

    When contracts are incomplete, the law must rely on default rules to resolve any issues that have not been explicitly addressed by the parties. Some default rules (called 'majoritarian' or 'market-mimicking') are designed to be left in place by most parties, and thus are chosen to reflect an efficient allocation of rights and duties. Others (called 'information-forcing' or 'penalty' default

  15. Team Teaching School Law

    ERIC Educational Resources Information Center

    Vanko, John G.; Rogina, Raymond P.

    2005-01-01

    Graduate students preparing themselves for a career in school administration are typically apprehensive about the legal issues they will face in their first administrative position. After teaching school law for the first time, the author believed that there had to be a more effective way to reach these students rather than the traditional methods…

  16. Newton's Laws Demonstrations

    NSDL National Science Digital Library

    Don Rathjen

    2007-01-01

    In this collection of demonstrations, learners explore Newton's Laws of Motion. These seventeen quick activities investigate air resistance, acceleration, terminal velocity, inertia, action-reaction, and other key concepts related to forces and motion. These demonstrations can be coupled together or conducted individually.

  17. ISI law enforcement research

    Microsoft Academic Search

    Jeff Lacoss; John Granacki; Jack Wills

    1998-01-01

    The Advanced System Division of ISI is engaged in a number of projects focused on using commercial technologies to produce a low-cost system with extensive capability for reconfiguration and experimentation. Low-cost platforms for mobile computing and communications enable experimental approaches to determining requirements for law enforcement and military field applications. Unfortunately, flexible COTS hardware is generally unavailable, forcing experiments to

  18. Discretion in Administrative Law.

    ERIC Educational Resources Information Center

    Grey, J.

    1979-01-01

    Clarifies the concept of discretion, demonstrates how far the courts have been willing to tolerate it, and charts some new paths that appear to be opening before those who advocate wide judicial review. Available from the Osgoode Hall Law School, York University, 4700 Keele Street, Downsview, Ontario, Canada, M3J 2R5; $8.00/issue. (Author/IRT)

  19. Avogadro's Hypothesis (or Law)

    Microsoft Academic Search

    S. H. Woolhouse

    1910-01-01

    IN Prof. Tilden's ``Life of Mendeléeff'' in the current number of the Journal of the Chemical Society, I see that he refers repeatedly to the ``law'' of Avogadro. Sir William Ramsay, in his ``Modern Chemistry'', speaks of it as a ``hypothesis'', and this has surely been, until recently, the practice of chemists.

  20. Environmental Law II.

    ERIC Educational Resources Information Center

    Continuing Legal Education in Colorado, Inc., Denver.

    Presented are papers delivered at a 1976 Colorado environmental law conference. Included in the publication are the conference schedule, the text of nine papers, background information on authors, and bibliography listings for each paper. Titles and topics of the papers are the following: (1) Water Resources Development and the Environment…

  1. ADHD and School Law.

    ERIC Educational Resources Information Center

    Gregg, Soleil

    A review of the research and legal literature summarizes the status of attention deficit hyperactivity disorder (ADHD) under school law. Following a brief introduction, discussion of ADHD as a disability notes the impact of ADHD on overall functioning and provides a table of diagnostic criteria for subtypes of ADHD. The following section focuses…

  2. Kepler's Third Law

    NSDL National Science Digital Library

    Dr. Greg Bothun

    This applet shows the relative orbits of Earth and Mars as governed by Kepler's Laws. The purpose of the applet is to demonstrate why it takes approximately 2 years for a manned mission to Mars. To simulate other relative orbital mechanics, the orbits of the Earth and Mars can be changed to any arbitrary distance from the Sun.

  3. School Law Update, 1985.

    ERIC Educational Resources Information Center

    Jones, Thomas N., Ed.; Semler, Darel P., Ed.

    A wide variety of contemporary legal issues, involving all levels of public and private education, are addressed in the 20 papers in this volume. Written in law review style and including legal citations, the papers and authors included are: (1) "Who Runs the Schools" (Flygare); (2) "Copyright Issues in Computer-Assisted Instruction" (Helm); (3)…

  4. Physical and chemical microstructural damage in pressed CL-20 explosives

    NASA Astrophysics Data System (ADS)

    Demol, Gauthier; Sandusky, Harold W.

    2000-04-01

    The ultimate utility of CL-20 as an ingredient in explosive and propellant formulations will depend upon the ability to understand the factors that are responsible for batch-to-batch variability with respect to sensitivity, and also to control the sensitivity in formulations within acceptable limits. We used light microscopy of cold-mounted, polished samples to characterize CL-20 at various stages in its life cycle. The evolution of damage from the initial neat crystals of CL-20 to the ready-to-use pressed pellets shows that processing seriously damages the crystals. These crystals are very brittle, and several explanations are proposed.

  5. Micromechanics-based elastic-damage analysis of laminated composite structures

    Microsoft Academic Search

    S. H. Pyo; H. K. Lee

    2009-01-01

    Based on the micromechanics-based constitutive model, derived in our preceding work [Lee, H.K., Pyo, S.H., 2009. A 3D-damage model for fiber-reinforced brittle composites with microcracks and imperfect interfaces. Journal of Engineering Mechanics-ASCE, in press, doi:10.1061\\/(ASCE)EM.1943.7889.0000039.], incorporating a multi-level damage model and a continuum damage model, the overall elastic behavior and damage evolution of laminated composite structures are studied in detail.

  6. Clarifying Baker's Law

    PubMed Central

    Cheptou, P.-O.

    2012-01-01

    Background Baker's Law states that colonization by self-compatible organisms is more likely to be successful than colonization by self-incompatible organisms because of the ability for self-compatible organisms to produce offspring without pollination agents. This simple model has proved very successful in plant ecology and has been applied to various contexts, including colonizing or ruderal species, islands colonizers, invasive species or mating system variation across distribution ranges. Moreover, it is one of the only models in population biology linking two traits of major importance in ecology, namely dispersal and mating system. Although Baker's Law has stimulated a large number of empirical studies reporting the association of self-fertilization and colonizing ability in various contexts, the data have not established a general pattern for the association of traits. Scope In this paper, a critical position is adopted to discuss and clarify Baker's Law. From the literature referring to Baker's Law, an analysis made regarding how mating success is considered in such studies and discrepancies with population genetics theory of mating systems are highlighted. The data reporting the association of self-fertilization and colonizing ability are also briefly reviewed and the potential bias in interpretation is discussed. Lastly, a recent theoretical model analysing the link between colonizing ability and self-fertilization is considered. Conclusions Evolutionary predictions are actually more complex than Baker's intuitive arguments. It appears that Baker's Law encompasses a variety of ecological scenarios, which cannot be considered a priori as equivalent. Questioning what has been considered as self-evident for more than 50 years seems a reasonable objective to analyse in-depth dispersal and mating system traits. PMID:21685434

  7. Hagfors' law revisited

    NASA Astrophysics Data System (ADS)

    Sultan-Salem, Ahmed K.; Tyler, G. Leonard

    2006-04-01

    Hagfors' scattering law, ?°H($\\theta$), is in wide use in connection with the study of backscatter data from planetary surfaces because it provides good agreement with a variety of observations. The surface root-mean-square slope inferred on the basis of ?°H($\\theta$) is customarily taken as C-1/2, where C is the shape parameter in ?°H($\\theta$). The relationship between the surface slope and C is indefinite, however, because of the indeterminateness of the surface scales contributing to the scattering process. Moreover, the horizontal scale of the inferred slope obtained is not specified. As a consequence of limitations in the Kirchhoff approximation on which it is predicated, ?°H($\\theta$) does not conserve energy. The use of a fractional Brownian fractal surface model leads to a scattering law with the same functional form as ?°H($\\theta$) when the Hurst exponent characterizing the fractal model is 1/2. Fractal-based scattering laws, derived by applying the Kirchhoff approximation, suffer the same deficiency with regard to conservation of energy. In contrast to ?°H($\\theta$), slope information for fractal-based laws is explicit with respect to horizontal scale. Both ?°H($\\theta$) and fractal-based laws require that the illuminated surface area exceeds a certain value, which is a function of the electromagnetic wavelength and surface parameters, in order to reduce the surface radar cross section overestimation error, introduced by a mathematical approximation, below some specified value. This requirement may be necessary to take into account in experiments where the radar resolution cells are comparable in size to the wavelength, such as in Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS).

  8. Damaged Skylab Micrometeoroid Shield

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The Saturn V vehicle, carrying the unmarned orbital workshop for the Skylab-1 mission, lifted off successfully and all systems performed normally. Sixty-three seconds into flight, engineers in the operation support and control center saw an unexpected telemetry indication that signalled that damages occurred on one solar array and the micrometeoroid shield during the launch. The micrometeoroid shield, a thin protective cylinder surrounding the workshop protecting it from tiny space particles and the sun's scorching heat, ripped loose from its position around the workshop. This caused the loss of one solar wing and jammed the other. Still unoccupied, the Skylab was stricken with the loss of the heat shield and sunlight beat mercilessly on the lab's sensitive skin. Internal temperatures soared, rendering the station uninhabitable, threatening foods, medicines, films, and experiments. This image, taken during a fly-around inspection by the Skylab-2 crew, shows the damaged meteoroid shield being held by a thin aluminum strap entangled with green-hued remnants of the lost heat shield. The Marshall Space Flight Center (MSFC) developed, tested, rehearsed, and approved three repair options. These options included a parasol sunshade and a twin-pole sunshade to restore the temperature inside the workshop, and a set of metal cutting tools to free the jammed solar panel.

  9. Ion Implantation Damage in Quartz

    NASA Astrophysics Data System (ADS)

    Macaulay-Newcombe, R. G.

    This thesis is a report on a series of measurements of ion-bombardment effects on alpha -quartz crystals. Damage was produced in alpha -quartz (single-crystal SiO_2) by bombarding with ions of ^4He ^+ to ^{209} Bi^{++} in the energy range of 15-200 keV, at both 300 K and <=50 K. The samples were analysed in-situ with Rutherford backscattering/channeling, using 1-2 MeV ^4He^+ ions; data was obtained from both the oxygen and silicon peaks, so that damage stoichiometry could be calculated. At low ion fluences (~10^ {10}-10^{11} ions/mm^2) the apparent damage level increases linearly with fluence, but at rates of about 3-19 times greater than predicted by the modified Kinchin-Pease equation. At higher fluences (~ 10^{11}-10 ^{12} ions/mm^2 ) the rate of damage increases with fluence for elastic energy deposition rates of less than ~ 0.08 eV/atom, but remains constant for greater elastic energy deposition rates. At even higher ion fluences saturation of the damage occurs. It has been observed that the analysis beam creates damage at a rate dependent on the level of damage already present in the crystal; furthermore, the damage created by the analysis ions appears to be predominantly due to the inelastically deposited energy. Strain effects seem to greatly exaggerate the level of damage indicated by simple channeling calculations. A simple model is proposed to explain both the high rates of damage production and the non-stoichiometry of the damage. The model indicates that the effects of elastic energy deposition, inelastic energy deposition, strain produced by damage, and lattice relaxation into a "quasi-amorphous" state, all contribute to the apparent damage levels synergistically.

  10. Nondestructive Damage Detection in General Beams 

    E-print Network

    Dincal, Selcuk

    2010-12-08

    Figure 4.11 Damage Localization Result for Damage Case SB 1 Using EB Direct j? ......................................................................................... 78 Figure 4.12 Damage Extent and Severity Estimate for Damage Case SB 1... Using EB Direct j? ......................................................................................... 79 Figure 4.13 Damage Localization Result for Damage Case SB 2 Using EB Direct j...

  11. AN EXPERIMENTALCOMPUTATIONAL APPROACH TO THE INVESTIGATION OF DAMAGE EVOLUTION IN

    E-print Network

    Ghosh, Somnath

    - anical properties, as well as their ability to reduce life-cycle costs through enhanced thermal stability REINFORCED ALUMINUM MATRIX COMPOSITE M. LI1 , S. GHOSH1 { and O. RICHMOND2 1 Department of Aerospace: Computer simulation; Image analysis; Aluminum composites; Microstructure; Fracture and Fracture toughness 1

  12. RESULTS FROM CAVITATION DAMAGE EXPERIMENTS WITH MERCURY SPALLATION TARGETS AT THE LANSCE WNR IN 2008

    SciTech Connect

    Riemer, Bernie [ORNL] [ORNL; Abdou, Ashraf A [ORNL] [ORNL; Felde, David K [ORNL] [ORNL; Sangrey, Robert L [ORNL] [ORNL; Wendel, Mark W [ORNL] [ORNL

    2010-01-01

    Damage assessment from proton beam induced cavitation experiments on mercury spallation targets done at the LANSCE WNR facility has been completed. The experiments investigated two key questions for the Spallation Neutron Source target, namely, how damage is affected by flow velocity in the SNS coolant channel geometry, and how damage scales with proton beam intensity at a given constant charge per pulse. With regard to the former question, prior in-beam experiments indicated that the coolant channel geometry with stagnant mercury was especially vulnerable to damage which might warrant a design change. Yet other results indicated a reduction in damage with the introduction of flow. Using more prototypic to the SNS, the 2008 experiment damage results show the channel is less vulnerable than the bulk mercury side of the vessel wall. They also show no benefit from increasing channel flow velocity beyond nominal SNS speeds. The second question probed a consensus belief that damage scales with beam intensity (protons per unit area) by a power law dependence with exponent of around 4. Results from a 2005 experiment did not support this power law dependence but some observations were inconsistent and unexplained. These latest results show weaker damage dependence.

  13. A continuum description of the damage process in the arterial wall of abdominal aortic aneurysms.

    PubMed

    Marini, Giacomo; Maier, Andreas; Reeps, Christian; Eckstein, Hans-Henning; Wall, Wolfgang A; Gee, Michael W

    2012-01-01

    In the present work, we develop a three-dimensional isotropic finite-strain damage model for abdominal aortic aneurysm (AAA) wall that considers both the characteristic softening of the material caused by damage and the spatial variation of the material properties. A strain energy function is formulated that accounts for a hyperelastic, slightly compressible, isotropic material behavior during the elastic phase, whereas the damage process only contributes to the material response when the elastic limit of the AAA wall is exceeded. Material and damage parameters are obtained by fitting the strain energy function to the experimental data obtained by uniaxial tensile tests of freshly harvested AAA wall samples. The damage model extends the validity of the material law to a strain range of up to 50%. Purely elastic material laws for AAA wall are only valid for a strain range of up to 17%. In a series of finite element simulations of patient-specific AAAs, serving as numerical examples, we investigate the applicability of the damage model. The use of the damage model does not yield a more distinct identification of rupture-prone AAAs than other computational-based risk indices. However, the benefit of the finite-strain damage model is the potential capability to trigger growth and remodeling processes in mechanobiological models. PMID:25830207

  14. Stellar evolution.

    NASA Technical Reports Server (NTRS)

    Chiu, H.-Y. (editor); Muriel, A.

    1972-01-01

    Aspects of normal stellar evolution are discussed together with evolution near the main sequence, stellar evolution from main sequence to white dwarf or carbon ignition, the structure of massive main-sequence stars, and problems of stellar stability and stellar pulsation. Other subjects considered include variable stars, white dwarfs, close binaries, novae, early supernova luminosity, neutron stars, the photometry of field horizontal-branch stars, and stellar opacity. Transport mechanisms in stars are examined together with thermonuclear reactions and nucleosynthesis, the instability problem in nuclear burning shells, stellar coalescence, and intense magnetic fields in astrophysics. Individual items are announced in this issue.

  15. The Teaching of Constitutional Law in American Law Schools.

    ERIC Educational Resources Information Center

    Haimbaugh, George D., Jr.

    1981-01-01

    A survey of the teaching of constitutional law used questionnaires sent to the dean of every law school approved by the Association of American Law Schools or the American Bar Association. Responses describe the basic course, advanced courses and seminars, teachers, goals, and examinations. (MLW)

  16. Teaching "Law and Education" Outside the Law School.

    ERIC Educational Resources Information Center

    Simpson, Robert J., Ed.

    A symposium discussion is presented on the topic, "Teaching 'Law and Education' Outside the Law School." The participants were: Walter J. McCann of Harvard Graduate School of Education; E. Edmund Reutter, Jr., of Teachers College of Columbia University; Robert J. Simpson of University of Miami Center for Policy and Law in Education; Tyll Van Geel…

  17. Vermont Law School's Unique Master of Studies in Environmental Law.

    ERIC Educational Resources Information Center

    Suagee, Dean B.

    2003-01-01

    Vermont Law School offers a 1-year master of studies in environmental law for which the only prerequisite is a bachelor's degree. A fellowship program waives tuition and provides stipends for American Indians taking the program. Courses on federal Indian law complement the program. The Native community at nearby Dartmouth College provides social…

  18. Impact damage in composite laminates

    NASA Technical Reports Server (NTRS)

    Wang, Chung-Yue; Yew, Ching H.

    1990-01-01

    A low-velocity impact-damage model for quasi-symmetric graphite-fiber composite plates is presented. The distribution of damage in each layer of the plate was calculated by employing Di Sciuva's composite laminate theory together with Hashin's failure criterion for fiber-reinforced composites. The dynamic deformation of the target plate was represented by the lower vibrational modes of the plate. The principle of virtual work was applied in the formulation of the problem. In the analysis, the material was regarded as 'damaged' when its designed strength was reduced by the failure of its constituents. The constituent failures consisted of matrix crackings, fiber breakages, and delamination between layers. According to damage modes, the moduli of material in the damaged zone were reduced according to the failure criteria. The interaction between layers and its role in damage propagation were also studied.

  19. Incentive effects of class actions and punitive damages under alternative procedural regimes

    Microsoft Academic Search

    Marta Cenini; Barbara Luppi; Francesco Parisi

    2011-01-01

    In an economic perspective, punitive damages and class actions can be viewed as sharing a common economic function—creating\\u000a optimal deterrence. Building on Parisi and Cenini (Class actions for Europe: perspectives from law and economics, ELGAR, 2010), we study the effect of alternative procedural regimes on the effectiveness of punitive damages and class actions. Specifically,\\u000a we compare the workings of punitive

  20. Effect of material damage on the stress-strain state near a crack tip in creep

    NASA Astrophysics Data System (ADS)

    Astaf'ev, V. I.; Grigorova, T. V.; Pastukhov, V. A.

    1992-02-01

    The asymptotic stress and damage fields near the tip of a growing crack are determined for a creep-damaged material described by Rabotnov-Hayhurst-Leckie constitutive equations. It is found that the singular stress field, characteristic of the crack theory, is absent near the crack tip, which is consistent with the results of finite element solutions for tearing cracks. A crack growth law is obtained which provides a qualitative description of the crack growth process in stainless steels under constant loading.

  1. Damage in woven CFRP laminates subjected to low velocity impacts

    NASA Astrophysics Data System (ADS)

    Ullah, H.; Abdel-Wahab, A. A.; Harland, A. R.; Silberschmidt, V. V.

    2012-08-01

    Carbon fabric-reinforced polymer (CFRP) composites used in sports products can be exposed to different in-service conditions such as large dynamic bending deformations caused by impact loading. Composite materials subjected to such loads demonstrate various damage modes such as matrix cracking, delamination and, ultimately, fabric fracture. Damage evolution in these materials affects both their in-service properties and performance that can deteriorate with time. These processes need adequate means of analysis and investigation, the major approaches being experimental characterisation and non-destructive examination of internal damage in composite laminates. This research deals with a deformation behaviour and damage in woven composite laminates due to low-velocity dynamic out-of-plane bending. Experimental tests are carried out to characterise the behaviour of such laminates under large-deflection dynamic bending in un-notched specimens in Izod tests using a Resil Impactor. A series of low-velocity impact tests is carried out at various levels of impact energy to assess the energy absorbed and force-time response of CFRP laminates. X-ray micro computed tomography (micro-CT) is used to investigate material damage modes in the impacted specimens. X-ray tomographs revealed that through-thickness matrix cracking, inter-ply delamination and intra-ply delamination, such as tow debonding and fabric fracture, were the prominent damage modes.

  2. Simulating Evolution

    ERIC Educational Resources Information Center

    Stebbins, Robert C.; Allen, Brockenbrough

    1975-01-01

    Described are simulations that can be used to illustrate evolution by natural selection. Suggestions for simulating phenomena such as adaptive radiation, color match to background and vision of predators are offered. (BR)

  3. Radiation Damage Workshop

    NASA Technical Reports Server (NTRS)

    Stella, P. M.

    1984-01-01

    The availability of data regarding the radiation behavior of GaAs and silicon solar cells is discussed as well as efforts to provide sufficient information. Other materials are considered too immature for reasonable radiation evaluation. The lack of concern over the possible catastrophic radiation degradation in cascade cells is a potentially serious problem. Lithium counterdoping shows potential for removing damage in irradiated P-type material, although initial efficiencies are not comparable to current state of the art. The possibility of refining the lithium doping method to maintain high initial efficiencies and combining it with radiation tolerant structures such as thin BSF cells or vertical junction cells could provide a substantial improvement in EOL efficiencies. Laser annealing of junctions, either those formed ion implantation or diffusion, may not only improve initial cell performance but might also reduce the radiation degradation rate.

  4. Title Law Journal Credit Category Academic Credit

    E-print Network

    Zhuang, Yu

    "). Texas Tech Administrative Law Journal Credit. Students working on this journal are selected in the same Administrative Law Journal, Estate Planning & Community Property Law Journal, Business & Bankruptcy Law Journal Administrative Law Journal, Estate Planning & Community Property Law Journal, Business & Bankruptcy Law Journal

  5. Law Libraries: The Next Generation.

    ERIC Educational Resources Information Center

    Edmonds, Ed

    1993-01-01

    Reports on the 1993 annual conference of the American Association of Law Libraries (AALL). Topics covered include the future of law librarianship, access to government information, copyright, library school closings, the Internet, and the impact of global information needs. (EAM)

  6. Faraday diagnostics for R-damage

    SciTech Connect

    Oro, David M [Los Alamos National Laboratory; Tabaka, Leonard J [Los Alamos National Laboratory

    2011-01-13

    ALT-3 and R-Damage are experiments to be executed in collaboration between LANL and VNIIEF personnel. They are planned to be fielded in Sarov, Russia at VNIIEF. Both experiments employ Russian explosively driven pulse-power systems to generate a pulse of electrical current that is used to drive the experiment. The current pulse will be measured with Faraday-rotation fiber-optic loops. Using this well known technique, the change in the current enclosed by the loops is determined by measuring the change in the magnetic field integrated along the fiber-optic loop by detecting the Faraday rotation of linearly polarized light traveling through the fiber. The amount of polarization rotation of the light is related to the integrated magnetic field and therefore the enclosed current (Ampere's law) through the Verdet constant which for the optical-fibers used in this experiment has been determined to within 1 %. The presentation describes how the technique will be employed in the R-Damage experiment.

  7. Rapid Disaster Damage Estimation

    NASA Astrophysics Data System (ADS)

    Vu, T. T.

    2012-07-01

    The experiences from recent disaster events showed that detailed information derived from high-resolution satellite images could accommodate the requirements from damage analysts and disaster management practitioners. Richer information contained in such high-resolution images, however, increases the complexity of image analysis. As a result, few image analysis solutions can be practically used under time pressure in the context of post-disaster and emergency responses. To fill the gap in employment of remote sensing in disaster response, this research develops a rapid high-resolution satellite mapping solution built upon a dual-scale contextual framework to support damage estimation after a catastrophe. The target objects are building (or building blocks) and their condition. On the coarse processing level, statistical region merging deployed to group pixels into a number of coarse clusters. Based on majority rule of vegetation index, water and shadow index, it is possible to eliminate the irrelevant clusters. The remaining clusters likely consist of building structures and others. On the fine processing level details, within each considering clusters, smaller objects are formed using morphological analysis. Numerous indicators including spectral, textural and shape indices are computed to be used in a rule-based object classification. Computation time of raster-based analysis highly depends on the image size or number of processed pixels in order words. Breaking into 2 level processing helps to reduce the processed number of pixels and the redundancy of processing irrelevant information. In addition, it allows a data- and tasks- based parallel implementation. The performance is demonstrated with QuickBird images captured a disaster-affected area of Phanga, Thailand by the 2004 Indian Ocean tsunami are used for demonstration of the performance. The developed solution will be implemented in different platforms as well as a web processing service for operational uses.

  8. Jurist: Books on Law

    NSDL National Science Digital Library

    This site, a recent addition to Professor Bernard Hibbitts' Jurist site (discussed in the April 11, 1997 Scout Report), is a monthly publication edited by Ronald Collins and David Skover of the Seattle University School of Law. Highlight of the site, of course, is the review section, with five to ten reviewed new books (excluding casebooks and textbooks) per issue. There are also notices of new books in 37 subject categories, one review of an old book, and a list of law publishers. The May 1998 issue is a special issue on Closed Chambers: The First Eyewitness Account of the Epic Struggles Inside the Supreme Court, by Edward Lazarus. It includes a RealPlayer interview with the author (transcript available), in addition to six commentaries.

  9. Characteristics of shear damage for 60Sn-40Pb solder material

    SciTech Connect

    Fang, H.E. [Sandia National Labs., Albuquerque, NM (United States); Chow, C.L.; Wei, Y. [Univ. of Michigan, Dearborn, MI (United States). Dept. of Mechanical Engineering

    1997-12-31

    This paper presents an investigation of the development of a continuum damage model capable of accurately analyzing shear damage in 60Sn-40Pb solder material. Based on the theory of damage mechanics, an internal state variable known as the damage variable is introduced to characterize material degradation caused by the change of material microstructures under load. A damage surface in stress space is proposed to quantify damage initiation and its successive expanding surfaces to represent damage hardening. With the aid of irreversible thermodynamics, the damage-coupled constitutive equations and the damage evolution equations are established. A failure criterion is proposed based on the accumulation of overall damage in the material. The damage model is implemented in a general purpose finite element program ABAQUS through its user-defined material subroutine UMAT. The program is applied to predict shear deformation in a notched specimen. The predicted failure mode and maximum load agree well with those measured experimentally. The effect of finite element meshing on the numerical results is also examined and discussed.

  10. Survey of four damage models for concrete.

    SciTech Connect

    Leelavanichkul, Seubpong (University of Utah, Salt Lake City, UT); Brannon, Rebecca Moss (University of Utah, Salt Lake City, UT)

    2009-08-01

    Four conventional damage plasticity models for concrete, the Karagozian and Case model (K&C), the Riedel-Hiermaier-Thoma model (RHT), the Brannon-Fossum model (BF1), and the Continuous Surface Cap Model (CSCM) are compared. The K&C and RHT models have been used in commercial finite element programs many years, whereas the BF1 and CSCM models are relatively new. All four models are essentially isotropic plasticity models for which 'plasticity' is regarded as any form of inelasticity. All of the models support nonlinear elasticity, but with different formulations. All four models employ three shear strength surfaces. The 'yield surface' bounds an evolving set of elastically obtainable stress states. The 'limit surface' bounds stress states that can be reached by any means (elastic or plastic). To model softening, it is recognized that some stress states might be reached once, but, because of irreversible damage, might not be achievable again. In other words, softening is the process of collapse of the limit surface, ultimately down to a final 'residual surface' for fully failed material. The four models being compared differ in their softening evolution equations, as well as in their equations used to degrade the elastic stiffness. For all four models, the strength surfaces are cast in stress space. For all four models, it is recognized that scale effects are important for softening, but the models differ significantly in their approaches. The K&C documentation, for example, mentions that a particular material parameter affecting the damage evolution rate must be set by the user according to the mesh size to preserve energy to failure. Similarly, the BF1 model presumes that all material parameters are set to values appropriate to the scale of the element, and automated assignment of scale-appropriate values is available only through an enhanced implementation of BF1 (called BFS) that regards scale effects to be coupled to statistical variability of material properties. The RHT model appears to similarly support optional uncertainty and automated settings for scale-dependent material parameters. The K&C, RHT, and CSCM models support rate dependence by allowing the strength to be a function of strain rate, whereas the BF1 model uses Duvaut-Lion viscoplasticity theory to give a smoother prediction of transient effects. During softening, all four models require a certain amount of strain to develop before allowing significant damage accumulation. For the K&C, RHT, and CSCM models, the strain-to-failure is tied to fracture energy release, whereas a similar effect is achieved indirectly in the BF1 model by a time-based criterion that is tied to crack propagation speed.

  11. Inverse Square Law

    NSDL National Science Digital Library

    The Exploratorium

    2012-07-11

    In this math activity related to light, learners explore why a light, such as a candle or a streetlight, looks dimmer the farther away from it we get. The answer lies in the Inverse Square Law, which learners demonstrate using graph paper or perfboard. (Two methods are given for this activity.) Learners will discover that the intensity of light is described by the power distributed over an area.

  12. Newton's Second Law Experiment

    NSDL National Science Digital Library

    Fendt, Walter

    This applet simulates an experiment to study Newton's Second Law. A mass sliding on a horizontal surface is connected by a string to a hanging mass. The value of the two masses and the coefficient of friction can be set by the user. The user can use a timer to gather data for the motion of the sliding mass as a function of time. This applet is a part of a large collection of physics applets, available in a wide range of languages.

  13. Future Weapons, Past Laws

    Microsoft Academic Search

    Kenneth Anderson; Oren Gross; Ashley Deeks; Gregory McNeal

    2012-01-01

    The laws governing armed conflicts—both those attempting to regulate the legality of going to war (jus ad bellum) and the rules pertaining to the conduct of warfare (jus in bello)—have seen changes and modifications in reaction to shifts in the nature of warfare, in general, and the introduction of new technologies of communication, transportation, manufacturing and destruction, in particular.\\u000aYet,

  14. Hagfors' law revisited

    Microsoft Academic Search

    Ahmed K. Sultan-Salem; G. Leonard Tyler

    2006-01-01

    Hagfors' scattering law, sigma°H($\\\\theta$), is in wide use in connection with the study of backscatter data from planetary surfaces because it provides good agreement with a variety of observations. The surface root-mean-square slope inferred on the basis of sigma°H($\\\\theta$) is customarily taken as C-1\\/2, where C is the shape parameter in sigma°H($\\\\theta$). The relationship between the surface slope and C

  15. Hagfors' law revisited

    Microsoft Academic Search

    Ahmed K. Sultan-Salem; G. Leonard Tyler

    2006-01-01

    Hagfors' scattering law, ?°H($\\\\theta$), is in wide use in connection with the study of backscatter data from planetary surfaces because it provides good agreement with a variety of observations. The surface root-mean-square slope inferred on the basis of ?°H($\\\\theta$) is customarily taken as C?1\\/2, where C is the shape parameter in ?°H($\\\\theta$). The relationship between the surface slope and C

  16. Biot-Savart Law

    NSDL National Science Digital Library

    VU Bioengineering RET Program, School of Engineering,

    This lesson begins with a demonstration prompting students to consider how current generates a magnetic field and the direction of the field that is generated. Through formal lecture, students learn Biot-Savart's law in order to calculate, most simply, the magnetic field produced in the center of a circular current carrying loop. For applications, students find it is necessary to integrate the field produced over all small segments in an actual current carrying wire.

  17. Kinetics of wealth and the Pareto law.

    PubMed

    Boghosian, Bruce M

    2014-04-01

    An important class of economic models involve agents whose wealth changes due to transactions with other agents. Several authors have pointed out an analogy with kinetic theory, which describes molecules whose momentum and energy change due to interactions with other molecules. We pursue this analogy and derive a Boltzmann equation for the time evolution of the wealth distribution of a population of agents for the so-called Yard-Sale Model of wealth exchange. We examine the solutions to this equation by a combination of analytical and numerical methods and investigate its long-time limit. We study an important limit of this equation for small transaction sizes and derive a partial integrodifferential equation governing the evolution of the wealth distribution in a closed economy. We then describe how this model can be extended to include features such as inflation, production, and taxation. In particular, we show that the model with taxation exhibits the basic features of the Pareto law, namely, a lower cutoff to the wealth density at small values of wealth, and approximate power-law behavior at large values of wealth. PMID:24827290

  18. Feral swine damage and damage management in forested ecosystems

    Microsoft Academic Search

    Tyler A. Campbell; David B. Long

    2009-01-01

    Invasive feral swine (Sus scrofa) cause deleterious impacts to ecosystem processes and functioning throughout their worldwide distribution, including forested ecosystems in the United States. Unfortunately, many feral swine damage management programs are conducted in a piecemeal fashion, are not adequately funded, and lack clearly stated or realistic objectives. This review paper identifies damage caused by feral swine to forest resources

  19. Philadelphia University Faculty of law

    E-print Network

    /or corequisite (s): administrative law 2 Course Level: Third Year Credit hours: 3 Credit HoursLecture Time Prerequisite: Administrative law (2) Module number: 420363 Module number: 420226 The administrative justicePhiladelphia University Faculty of law Department of -------------- ---------- semester, 2007

  20. The tides of customary law

    Microsoft Academic Search

    Mark Finnane

    This confusion surrounding the standing of customary law in the criminal justice system was a symptom of the disturbed state of an unfinished colonialism. 'Excuse of tribal law to be axed', blared a headline in The Australian newspaper, leading the charge. Three days later the same campaigning newspaper devoted an editorial to the subject: 'One Law for All: Our legal

  1. Philadelphia University Faculty of law

    E-print Network

    Philadelphia University Faculty of law Department of -------------- ---------- semester, 2007/or corequisite (s): Law of Civil Procedures Course Level: Fourth year Credit hours: 3 Credit HoursLecture Time applications Prerequisite: Civil law of procedure Module number: 410494 Module number: 410391 This course

  2. Philadelphia University Faculty of law

    E-print Network

    Philadelphia University Faculty of law Department of -------------- ---------- semester, 2007/2008 Course Syllabus Course code: Course Title: Administrative Law 2: Course prerequisite (s) and/or corequisite (s): Administrative Law 1 Course Level: Third Year Credit hours: 3 Credit HoursLecture Time

  3. Philadelphia University Faculty of law

    E-print Network

    Philadelphia University Faculty of law Department of -------------- ---------- semester, 2007/2008 Course Syllabus Course code: 420242 Course Title: Public International Law 2 Course prerequisite (s) and/or corequisite (s): public international law 1 Course Level: Second year Credit hours: 3 Credit HoursLecture Time

  4. Reordering American Constitutional Law Teaching.

    ERIC Educational Resources Information Center

    Gerber, Scott D.

    1994-01-01

    Maintains that constitutional law is the cornerstone of an undergraduate public law curriculum. Asserts that there is a welcome trend toward teaching the subject over a two-semester sequence, instead of only one. Describes course content and teaching strategies used in a college constitutional law course. (CFR)

  5. The Death of Labor Law?

    Microsoft Academic Search

    Cynthia L. Estlund

    2006-01-01

    This review tells three interlocking tales of decline, each with its respective prognosis for recovery: the declines of labor law scholarship, labor law, and organized labor. The relationship between the latter two and the role that a reformed labor law might play in reviving organized labor are matters of continuing controversy. In the meantime, two developments on the ground suggest

  6. Whats Inside: Child Labor Laws

    E-print Network

    Veiga, Pedro Manuel Barbosa

    Whats Inside: · Child Labor Laws · Computer Training Update · Annual Performance Review · Meet the age of eighteen (18). The Oklahoma Department of Labor has specific child labor laws that apply. Below) 744-5373. CHILD LABOR LAWS ANNUAL PERFORMANCE REVIEW Policy and Procedures 3-0741, Performance

  7. Whats Inside: Child Labor Laws

    E-print Network

    Veiga, Pedro Manuel Barbosa

    Whats Inside: Child Labor Laws Annual Performance Review BDS Reminders All International Part- Time are under the age of eighteen (18). The Oklahoma Department of Labor has specific child labor laws work up to eight hours a day, 40 hours in any one week, and only between the hours of CHILD LABOR LAWS

  8. Nebraska Law University of Nebraska

    E-print Network

    Farritor, Shane

    Nebraska Law University of Nebraska Reciprocity Policy Updated: August 2010 The University of Nebraska College of Law Office of Career Services' policy concerning placement assistance provided to students/graduates of other law schools is as follows: 1). Requests for reciprocity must be received from

  9. Origin of the Natural Laws

    Microsoft Academic Search

    Milo Wolff; Geoff Haselhurst

    2000-01-01

    Before the wave theory of matter natural laws were observed, but not predicted by a physical cause. Their existence was faith in Nature, a God. Now, using a spherical wave structure of the electron-positron, natural laws are predicted exactly as observed - not God-given, but a consequence of the wave structure of matter. The prediction of laws, of electron spin,

  10. Requirements Evolution Empirical Analyses

    E-print Network

    Felici, Massimo

    Requirements Evolution Empirical Analyses Massimo Felici 18 July 2001, ITC-IRST/ARS, Trento, Italy Massimo Felici Requirements Evolution ITC-IRST/ARS #12;Requirements Evolution 1 Overview · Why Requirements Evolution? · Empirical Requirements Evolution: Two Industrial Case Studies · Discussion

  11. Shock Initiation of Damaged Explosives

    SciTech Connect

    Chidester, S K; Vandersall, K S; Tarver, C M

    2009-10-22

    Explosive and propellant charges are subjected to various mechanical and thermal insults that can increase their sensitivity over the course of their lifetimes. To quantify this effect, shock initiation experiments were performed on mechanically and thermally damaged LX-04 (85% HMX, 15% Viton by weight) and PBX 9502 (95% TATB, 5% Kel-F by weight) to obtain in-situ manganin pressure gauge data and run distances to detonation at various shock pressures. We report the behavior of the HMX-based explosive LX-04 that was damaged mechanically by applying a compressive load of 600 psi for 20,000 cycles, thus creating many small narrow cracks, or by cutting wedge shaped parts that were then loosely reassembled, thus creating a few large cracks. The thermally damaged LX-04 charges were heated to 190 C for long enough for the beta to delta solid - solid phase transition to occur, and then cooled to ambient temperature. Mechanically damaged LX-04 exhibited only slightly increased shock sensitivity, while thermally damaged LX-04 was much more shock sensitive. Similarly, the insensitive explosive PBX 9502 was mechanically damaged using the same two techniques. Since PBX 9502 does not undergo a solid - solid phase transition but does undergo irreversible or 'rachet' growth when thermally cycled, thermal damage to PBX 9502 was induced by this procedure. As for LX-04, the thermally damaged PBX 9502 demonstrated a greater shock sensitivity than mechanically damaged PBX 9502. The Ignition and Growth reactive flow model calculated the increased sensitivities by igniting more damaged LX-04 and PBX 9502 near the shock front based on the measured densities (porosities) of the damaged charges.

  12. Finite element analysis of interfacial and local damage in metal matrix composites

    SciTech Connect

    Voyiadjis, G.Z.; Park, T. [Louisiana State Univ., Baton Rouge, LA (United States)

    1995-12-31

    The proposed micromechanical damage composite model used here is such that separate local constitutive damage relations are used for each of the matrix and the fiber. This is coupled with the interfacial damage between the matrix and the fiber exclusively. The damage relations are linked to the overall response through a certain homogenization procedure. The elasto-plastic stiffness tensor is derived for the damaged composite. Numerical solutions are obtained using the finite element method for the proposed theory for two types of laminate layups (0/90){sub s} and ({+-} 45){sub s} each consisting of four plies and compared with experimental results. A very good correlation is obtained between the experimental and numerical results. In addition to the damage evolution, the development of plastic zones and the stress-strain response are shown for the two types of laminated layups.

  13. Fundamental destruction of information and conservation laws

    E-print Network

    Jonathan Oppenheim; Benni Reznik

    2009-02-13

    Theories which have fundamental information destruction or decoherence are motivated by the black hole information paradox where one appears to have pure states evolving into mixed states. However such theories have either violated conservation laws, or are highly non-local. Here, we show that the tension between conservation laws and locality can be circumvented by constructing a relational theory of information destruction. In terms of conservation laws, we derive a generalisation of Noether's theorem for general theories, and show that symmetries imply a strong restriction on the type of evolution permissable. With respect to locality, we distinguish violations of causality from the creation or destruction of space-like seperated correlations. We show that violations of causality need not occur in a relational framework, although one can have situations where correlations decay faster than one might otherwise expect or can be created over spatial distances. This creation or destruction of correlations cannot be used to signal superluminally, and thus no violation of causality occurs. We prove that theories with information destruction can be made time-symmetric, thus impossing no arrow of time.

  14. An Internal Damage Model for Viscoelastic-Viscoplastic Energetic Materials

    NASA Astrophysics Data System (ADS)

    Matheson, Erik; Drumheller, Doug; Baer, Mel

    1999-06-01

    A theoretical foundation constraining the forms of mechanical damage models for visocelastic-viscoplastic energetic materials is developed. The theory is cast in terms of a viscoelastic-viscoplastic deviatoric stress tensor and a scalar viscoelastic-viscoplastic distention strain rate model. The constitutive forms of the deviatoric stress tensor and the distention strain rates are constrained by the second law of thermodynamics ensuring that the models will be dissipative. Additionally, a damage model is formulated that is driven by the mechanical response of the material and which modifies the constitutive models for the stress deviator and the distention strain rates. The deviatoric strain rates are reduced with increasing damage while the material is distended, but are computed normally when there is no distention. The stress deviator is computed in the normal manner using the modified strain rates. The distention strain rates are also modified by the damage so that no porosity may evolve until there is finite damage. The models are implemented in the CTH shock physics code, and comparisons to test data are made.

  15. Damage properties simulations of self-healing composites.

    PubMed

    Chen, Cheng; Ji, Hongwei; Wang, Huaiwen

    2013-10-01

    Self-healing materials are inspired by biological systems in which damage triggers an autonomic healing response. The damage properties of a self-healing polymer composite were investigated by numerical simulation in this paper. Unit cell models with single-edge centered crack and single-edge off-centered crack were employed to investigate the damage initiation and crack evolution by the extended finite element method (XFEM) modeling. The effect of microcapsule's Young's modulus on composites was investigated. Result indicates the microcapsule's Young's modulus has little effect on the unit cell's carrying capacity. It was found that during the crack propagation process, its direction is attracted toward the microcapsules, which makes it helpful for the microcapsules to be ruptured by the propagating crack fronts resulting in release of the healing agent into the cracks by capillary action. PMID:24245129

  16. Nondestructive Damage Evaluation in Ceramic Matrix Composites for Aerospace Applications

    PubMed Central

    Dassios, Konstantinos G.; Kordatos, Evangelos Z.; Aggelis, Dimitrios G.; Matikas, Theodore E.

    2013-01-01

    Infrared thermography (IRT) and acoustic emission (AE) are the two major nondestructive methodologies for evaluating damage in ceramic matrix composites (CMCs) for aerospace applications. The two techniques are applied herein to assess and monitor damage formation and evolution in a SiC-fiber reinforced CMC loaded under cyclic and fatigue loading. The paper explains how IRT and AE can be used for the assessment of the material's performance under fatigue. IRT and AE parameters are specifically used for the characterization of the complex damage mechanisms that occur during CMC fracture, and they enable the identification of the micromechanical processes that control material failure, mainly crack formation and propagation. Additionally, these nondestructive parameters help in early prediction of the residual life of the material and in establishing the fatigue limit of materials rapidly and accurately. PMID:23935428

  17. ORIGINAL PAPER Mathematical modeling of evolution. Solved and open problems

    E-print Network

    Schuster, Peter

    on variation and natural selection is due to the great naturalist Charles Darwin who derived it from a wealth are natural selection, Men- del's laws of inheritance, optimization by mutation and selection, and neutral of flowreactor. Keywords Error threshold Á Molecular evolution Á Natural selection Á Neutral evolution Á Quasi

  18. DR Reactor VSR channel damage

    Microsoft Academic Search

    F. J. Kempf; J. K. Rawlins

    1961-01-01

    On July 11, 1961 the Ball 3X System at DR Reactor was inadventently tripped. All vertical safety rods dropped and all channels were filled with balls. This report has the twofold purpose of documenting borescope observations of ten vertical rod channels at DR Reactor and recording the estimated extent of graphite damage resulting from the above incident. Channel damage data

  19. THE DYNAMICS OF RADIATION DAMAGE

    Microsoft Academic Search

    Vineyard; A. N. Goland; M. Milgram; G. H. Vineyard

    1960-01-01

    Calculations of radiation damage to face-centered-cubic metallic ; crystals, in particular copper crystals, are presented to give a more intimate ; view of events occurring in the lattice at low and moderate energies. The ; results show that damage at low energies consists of vacancies and interstitials ; and that the regular arrangement of atoms on a lattice has an

  20. Laser Damage Inspection Final Report

    Microsoft Academic Search

    J T Salmon; J M Brase; E S Bliss; C J Carrano; L M Kegelmeyer; M G Miller; C D Orth; R A Sacks

    2001-01-01

    Large, high-power laser systems are often designed as reimaging multipass cavities to maximize the extraction of energy from the amplifiers. These multipass cavities often have vacuum spatial filters that suppress the growth of beam instability via B-integral effects. These spatial filters also relay images of laser damage, often nearly superimposing these images in common planes. Also, the fluence damage threshold

  1. Grinding induced damage in ceramics

    Microsoft Academic Search

    Bi Zhang; X. L Zheng; H Tokura; M Yoshikawa

    2003-01-01

    Although grinding is widely used as a productive technique for finishing ceramic components in the manufacturing industry, it often causes damage to the machined components. The exact nature, the manner and the penetration depth of grinding-induced damage are, however, still not clear, leaving many uncertainties and sometimes danger in using ceramics for structural applications. This paper presents research results on

  2. Structural Damage Assessment under Uncertainty

    Microsoft Academic Search

    Israel Lopez Martinez

    2010-01-01

    Structural damage assessment has applications in the majority of engineering structures and mechanical systems ranging from aerospace vehicles to manufacturing equipment. The primary goals of any structural damage assessment and health monitoring systems are to ascertain the condition of a structure and to provide an evaluation of changes as a function of time as well as providing an early-warning of

  3. Behind the Evolution/Creation Controversy.

    ERIC Educational Resources Information Center

    Parker, Franklin

    This paper discusses the historical background of the creationist movement, presents Federal Judge Overton's analysis of why and how the Creationists got the equal time evolution/creation teaching law passed in Arkansas, and examines how scientists and educators are reacting to the controversy. Creationists were set back when Overton declared…

  4. SELFSIMILAR FOLD EVOLUTION UNDER PRESCRIBED ENDSHORTENING

    E-print Network

    Bath, University of

    embedded in a homogeneous matrix subject to compression parallel to the layer. The creation, however, it has become clear that fold evolution under prescribed end­shortening (or total strain) may layer embedded in a vis­ cous matrix (see Figure 1). The constitutional laws are linear, and small

  5. Eco-design with TRIZ laws of evolution

    Microsoft Academic Search

    Davide Russo; Daniele Regazzoni; Tiziano Montecchi

    2011-01-01

    Sustainability is one of the most recent theme designers have to deal with and sustainability parameters are quickly gaining the top of the list of the requirements any product has to fulfil. Due to standards, legal regulation and customer growing awareness of environmental issues, engineers cannot avoid turning their everyday activities from design to eco-design. By the way, a significant

  6. A metallography and x-ray tomography study of spall damage in ultrapure Al

    SciTech Connect

    Qi, M. L. [School of Science, Wuhan University of Technology, Wuhan, Hubei 430070 (China); HPSynC@Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Bie, B. X. [School of Science, Wuhan University of Technology, Wuhan, Hubei 430070 (China); The Peac Institute of Multiscale Sciences and Sichuan University, Chengdu, Sichuan 610207 (China); Zhao, F. P.; Fan, D.; Luo, S. N., E-mail: sluo@pims.ac.cn [The Peac Institute of Multiscale Sciences and Sichuan University, Chengdu, Sichuan 610207 (China); Hu, C. M. [HPSynC@Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); National Key Laboratory of Shock Wave and Detonation Physics, Chinese Academy of Engineering Physics, Mianyang, Sichuan 621900 (China); Ran, X. X. [School of Science, Wuhan University of Technology, Wuhan, Hubei 430070 (China); Xiao, X. H. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Yang, W. G., E-mail: wenge@aps.anl.gov [HPSynC@Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Li, P. [National Key Laboratory of Shock Wave and Detonation Physics, Chinese Academy of Engineering Physics, Mianyang, Sichuan 621900 (China)

    2014-07-15

    We characterize spall damage in shock-recovered ultrapure Al with metallography and x-ray tomography. The measured damage profiles in ultrapure Al induced by planar impact at different shock strengths, can be described with a Gaussian function, and showed dependence on shock strengths. Optical metallography is reasonably accurate for damage profile measurements, and agrees within 10–25% with x-ray tomography. Full tomography analysis showed that void size distributions followed a power law with an exponent of ? = 1.5 ± 2.0, which is likely due to void nucleation and growth, and the exponent is considerably smaller than the predictions from percolation models.

  7. Ultrasonic investigation of damage progression in concrete

    NASA Astrophysics Data System (ADS)

    Shokouhi, Parisa; Lorenz, Anna

    2014-02-01

    Coherent and diffuse ultrasonic measurements are used to monitor the state of progressive damage in concrete under compressive loading. The results obtained during a single load cycle experiment are discussed in this paper. In this experiment, uniaxial compression was gradually applied (stress-controlled) to a prismatic plain concrete specimen in small incremental steps. At each load step, the strain (and not stress) was held constant until a series of ultrasonic measurements were completed. Ultrasonic measurements were taken in two directions: parallel and perpendicular to the loading axis. Identical longitudinal (P-wave) dry-contact transducers of center frequency of about 100 KHz were used in both directions. The time scale of the signals was chosen long enough to allow the recording of ultrasonic coda. The evolutions of coherent P-wave velocities, diffuse ultrasonic wave velocities, diffusivity and diffusion (at 100 KHz) with the increasing load are demonstrated and discussed.

  8. Empirical Scaling Laws of Rocket Exhaust Cratering

    NASA Technical Reports Server (NTRS)

    Donahue, Carly M.; Metzger, Philip T.; Immer, Christopher D.

    2005-01-01

    When launching or landing a space craft on the regolith of a terrestrial surface, special attention needs to be paid to the rocket exhaust cratering effects. If the effects are not controlled, the rocket cratering could damage the spacecraft or other surrounding hardware. The cratering effects of a rocket landing on a planet's surface are not understood well, especially for the lunar case with the plume expanding in vacuum. As a result, the blast effects cannot be estimated sufficiently using analytical theories. It is necessary to develop physics-based simulation tools in order to calculate mission-essential parameters. In this work we test out the scaling laws of the physics in regard to growth rate of the crater depth. This will provide the physical insight necessary to begin the physics-based modeling.

  9. Laser damage in yttrium orthophosphate

    NASA Astrophysics Data System (ADS)

    Allen, R.; Esterowitz, L.; Klein, P. H.; Nicolai, V. O.; Zwicker, W. K.

    1980-07-01

    Laser damage experiments on single crystal blades of yttrium orthophosphate were performed. Crystals were grown by slow cooling of a flux containing lead pyrophosphate. Optical absorption is small from about 300 nm to about 3200 nm, approximating the transmission of calcite. A 1.06 micrometer neodymium glass laser with Q-switched pulse duration of 17 ns was used for damage measurements. The laser beam (0.025 cm FWHM) was focussed on the large face of the YPO4 crystals. Visible damage was always observed at front and back crystal surfaces following exposure to pulses averaging 3.6 GW/square centimeter or more. No visible damage was found in YPO4 at power densities less than 2.2 - 2.4 GW/square centimeter. Calcite crystals showed damage at somewhat smaller power densities.

  10. The physics of evolution

    NASA Astrophysics Data System (ADS)

    Eigen, Manfred

    1988-12-01

    The Darwinian concept of evolution through natural selection has been revised and put on a solid physical basis, in a form which applies to self-replicable macromolecules. Two new concepts are introduced: sequence space and quasi-species. Evolutionary change in the DNA- or RNA-sequence of a gene can be mapped as a trajectory in a sequence space of dimension ?, where ? corresponds to the number of changeable positions in the genomic sequence. Emphasis, however, is shifted from the single surviving wildtype, a single point in the sequence space, to the complex structure of the mutant distribution that constitutes the quasi-species. Selection is equivalent to an establishment of the quasi-species in a localized region of sequence space, subject to threshold conditions for the error rate and sequence length. Arrival of a new mutant may violate the local threshold condition and thereby lead to a displacement of the quasi-species into a different region of sequence space. This transformation is similar to a phase transition; the dynamical equations that describe the quase-species have been shown to be analogous to those of the two-dimensional Ising model of ferromagnetism. The occurrence of a selectively advantageous mutant is biased by the particulars of the quasi-species distribution, whose mutants are populated according to their fitness relative to that of the wild-type. Inasmuch as fitness regions are connected (like mountain ridges) the evolutionary trajectory is guided to regions of optimal fitness. Evolution experiments in test tubes confirm this modification of the simple chance and law nature of the Darwinian concept. The results of the theory can also be applied to the construction of a machine that provides optimal conditions for a rapid evolution of functionally active macromolecules. An introduction to the physics of molecular evolution by the author has appeared recently.1 Detailed studies of the kinetics and mechanisms of replication of RNA, the most likely candidate for early evolution2,3, and of the implications on natural selection have been given in Refs. 4 and 5. The quasi-species model has been constructed in Refs. 6 and 7 using the concept of sequence space. Subsequently various methods have been invented to elucidate this concept and to relate it to the theory of critical phenomena 8-19. The instability of the quasi-species at the error threshold is discussed in Ref. 10. Evolution experiments with RNA strands in test tubes are described in Refs. 21 and 22.

  11. Evolution of biological information.

    PubMed

    Schneider, T D

    2000-07-15

    How do genetic systems gain information by evolutionary processes? Answering this question precisely requires a robust, quantitative measure of information. Fortunately, 50 years ago Claude Shannon defined information as a decrease in the uncertainty of a receiver. For molecular systems, uncertainty is closely related to entropy and hence has clear connections to the Second Law of Thermodynamics. These aspects of information theory have allowed the development of a straightforward and practical method of measuring information in genetic control systems. Here this method is used to observe information gain in the binding sites for an artificial 'protein' in a computer simulation of evolution. The simulation begins with zero information and, as in naturally occurring genetic systems, the information measured in the fully evolved binding sites is close to that needed to locate the sites in the genome. The transition is rapid, demonstrating that information gain can occur by punctuated equilibrium. PMID:10908337

  12. Transgender Law and Policy Institute

    NSDL National Science Digital Library

    The Transgender Law and Policy Institute aims to advance transgender equality through advocating for non-discrimination laws and policy change. The number of transgender people in the United States population ranges from two to five percent and a smaller number are transsexual. Visitors will find that one of the many features on this very thorough site is under the "Non-discrimination Laws" link, which consists of lists, maps, and charts of which states and municipalities have non-discrimination laws that include gender identity and expression. Some of these laws include prohibiting discrimination in public employment and policies regarding restrooms and other gender-based facilities. Visitors interested in reading about such transgender related litigation in criminal, immigration, medical, tax, discrimination, or tort law will appreciate the "Litigation: Case Law" link.

  13. Generalized second law of thermodynamics in Gauss-Bonnet braneworld

    E-print Network

    Ahmad Sheykhi; Bin Wang

    2009-07-25

    We investigate the validity the generalized second law of thermodynamics in a general braneworld model with curvature correction terms on the brane and in the bulk, respectively. Employing the derived entropy expression associated with the apparent horizon, we examine the time evolution of the total entropy, including the derived entropy of the apparent horizon and the entropy of the matter fields inside the apparent horizon. We show that the generalized second law of thermodynamics is fulfilled on the 3-brane embedded in the 5D spacetime with curvature corrections.

  14. The second law of thermodynamics for pure quantum states

    E-print Network

    Sheldon Goldstein; Takashi Hara; Hal Tasaki

    2013-03-30

    A version of the second law of thermodynamics states that one cannot lower the energy of an isolated system by a cyclic operation. We prove this law without introducing statistical ensembles and by resorting only to quantum mechanics. We choose the initial state as a pure quantum state whose energy is almost E_0 but not too sharply concentrated at energy eigenvalues. Then after an arbitrary unitary time evolution which follows a typical "waiting time", the probability of observing the energy lower than E_0 is proved to be negligibly small.

  15. Deriving Darcy's Law

    NSDL National Science Digital Library

    Karen Salvage

    This exercise begins with a demonstration of fluid flow through porous sediment using a constant head permeameter, with the students conducting the experiment and collecting the data. The demo is followed by a Think-Pair-Share exercise in which the question is posed to the class: "What could we change in order to increase flow through the system?" The class then works through their brainstormed list of ideas, discussing each and evaluating whether it is correct or a misconception. The students derive Darcy's Law qualitatively, based upon the results of the Think-Pair-Share exercise and discussions.

  16. Beer's Law Lab

    NSDL National Science Digital Library

    The PhET project at the University of Colorado creates "fun, interactive, research-based simulations of physical phenomena." This particular one deals with Beer's Law. "The thicker the glass, the darker the brew, the less the light that passes through." Make colorful concentrated and dilute solutions and explore how much light they absorb and transmit using a virtual spectrophotometer! The simulation is also paired with a teachers' guide and related resources from PhET. The simulation is also available in multiple languages.

  17. Law and family planning.

    PubMed

    Gerber, P

    1984-03-17

    The decision in the Gillick case confirms that oral contraceptives (OCS) may be prescribed for adolescents under age 16 without their parent's knowlege or consent. And it is probable that to convey the information to parents will render the doctor guilty of professional miscnduct. This is true incases where the adolescent has reached the age of 16 and thus attained the age of consent, notwithstanding the decision in the Browne case. In that case, an elderly Birmingham general practitioner, Dr. Robert Browne, was chaged, on the information of a local family planning clinc, with serious professional misconduct when he told the father of a girl who had been his patient since birth that she was taking OCS. The girl had consulted a local family planning clinic, which had put her on OCS and conveyed the information to Dr. Browne in a confidential letter. Dr Browne had decided that her parents were the best people to counsel her, and since the information had been supplied by the clinic, "I could not accept from a third party a unilateral imposition of confidential information." The latter proposition is specious; the former is not a good defense at law. The decision of the General Medical Council's Disciplinary Committee in favor of Dr. Browne rests on tenuous reasoning. It was most likely wrong when it was handed down in 1971 and would almost certainly not be followed today. There is something in the Gillick case to infuriate every family doctor. At 1 level, the decision points the finger at as sensitive area of family medicine most often ignored by medical practitioners -- the provision of timely counseling, particularly in the area of sexual relations. The point has been reached where a family planning clinic's judgment can be lawfully substituted for that of parents on issues involving the moral and emotional development of their children. A doctor's obligation to maintain confidentiality does not come about by default, nor can it gan moral reinforcement as a result of some alleged "forfeiture" of parental rights, said to arise from a lack of adequate supervision, control, or even indifference. If is time for the law to consider the mess its "ad hoc" approach has created. The chaos is gargantuan in Australia. If the patient is capable of forming a sound judgment about the treatment to which he/she is consenting, and if a doctor concludes that the patient is an emancipated minor, then, in the present state of the law: a doctor commits no offense by prescribing OCS; having prescribed contraception to such a minor, it is professional misconduct to inform the patients that the minor is using contraception (Gillick); and in Queensland, unlawful carnal knowledge must be reported. PMID:6700486

  18. Statutory and Administrative Law for Geology Courses.

    ERIC Educational Resources Information Center

    Gutstadt, Allan

    1986-01-01

    Federal, state, and local statutory law is created by legislative bodies, administrative law by government agencies. Describes the nature of these laws and recommends that both statutory and administrative law be included in courses on legal aspects of geology. (JN)

  19. Simulating Perforation Permeability Damage and Cleanup

    SciTech Connect

    Morris, J.P.; Lomov, I.N.; Glenn, L.A.

    2000-09-01

    Completion of cased and cemented wells by shaped charge perforation causes its own damage to the formation, potentially reducing well productivity. In practice it is found that underbalance conditions clean up the damaged zone to some extent, however, the mechanisms of these processes are poorly understood. Most hydrocodes typically used to simulate rock response to shaped charge penetration do not provide permeability estimates. Furthermore, the time scales for formation clean up are potentially much longer than the period of jet penetration. We have developed a simple, yet accurate model for the evolution of porosity and permeability which can easily be incorporated into existing hydrocodes using information from the history of each cell. In addition, we have developed a code that efficiently simulates fines migration during the post-shot surge period using initial conditions taken directly from hydrocode simulations of jet penetration. Results from a one-dimensional model simulation are in excellent agreement with measured fines and permeability distributions. We also present two-dimensional numerical results which qualitatively reproduce experimentally obtained permeability maps for different values of underbalance. Although initial results have been promising, further comparison with experiment is essential to tune the coupling between the hydrocode and fines migration simulator. Currently the permeability model is most appropriate for high permeability sandstones (such as Berea), but with little effort, the model can be extended to other rock types, given sufficient experimental data.

  20. Simulating perforation permeability damage and cleanup

    SciTech Connect

    Morris, J P; Lomov, I N; Glenn, L A

    2000-12-15

    Completion of cased and cemented wells by shaped charge perforation causes its own damage to the formation, potentially reducing well productivity. In practice it is found that underbalance conditions clean up the damaged zone to some extent, however, the mechanisms of these processes are poorly understood. Most hydrocodes typically used to simulate rock response to shaped charge penetration do not provide permeability estimates. Furthermore, the time scales for formation clean up are potentially much longer than the period of jet penetration. We have developed a simple, yet accurate model for the evolution of porosity and permeability which can easily be incorporated into existing hydrocodes using information from the history of each cell. In addition, we have developed a code that efficiently simulates fines migration during the post-shot surge period using initial conditions taken directly from hydrocode simulations of jet penetration. Results from a one-dimensional model simulation are in excellent agreement with measured permeability distributions. We also present two-dimensional numerical results which qualitatively reproduce experimentally obtained permeability maps for different values of underbalance. Although initial results have been promising, further comparison with experiment is essential to tune the coupling between the hydrocode and fines migration simulator. Currently the permeability model is most appropriate for high permeability sandstones (such as Berea), but with little effort, the model can be extended to other rock types, given sufficient experimental data.