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1

Exponential evolution law of fretting wear damage in low-friction coatings for aerospace components  

Microsoft Academic Search

Friction coefficient evolution in low-friction coatings subjected to fretting wear was measured and described using a power-law relation for the development of Kachanov-type damage parameter as a function of accumulated reciprocal sliding distance. Fretting wear tests were performed using idealised contact geometry and loading conditions similar to those found in aero-engine components. A conventional dry film lubricant coating and a

Kyungmok Kim; Alexander M. Korsunsky

2008-01-01

2

On the origin of power-law rheology during the evolution of damage  

NASA Astrophysics Data System (ADS)

Many composite materials, including rocks undergoing semi-brittle failure by stress-enhanced corrosion reactions, exhibit power law scaling between bulk stress and strain rate. Chemical reaction rate theory on a uniform material predicts instead an exponential dependence, so mean field models to account for power law behaviour usually require a specific (often power-law) underlying distribution of local material properties to account for this, ideally conditioned on experimental and theoretical studies of microstructures. This mean field approach however breaks down at higher crack density, where bulk properties also depend on the collective dynamics or interaction of a population of microstructures. To examine the relative contribution of material heterogeneity and crack-crack interactions, we develop a 2-dimensional spring-dashpot network with breaking bonds, and investigate the influence of the distribution of microscopic relaxation times generate a macroscopic rheology of power-law form. Specifically, we examine the possibility of non-power-law microscopic heterogeneity, e.g. a Gaussian distribution of relaxation times, leading to macroscopic power-law rheology.

Kawada, Yusuke; Naylor, Mark; Touati, Sarah; Main, Ian

2010-05-01

3

Characterization of damage evolution in non linear media by means of power law exponent: Modeling and experiments  

NASA Astrophysics Data System (ADS)

Non linear Mesoscopic Elastic materials are characterized by the presence of a distribution of microscopic features like grain boundaries, phase transition and micro-cracks which result in a heterogeneous structure at the mesoscopic scale. It comes out from experimental observations that these materials are described by a non classical nonlinear Equation Of State (EOS) which has the particularity of being multivalued (presents hysteresis in the quasi static stress-strain relation) and amplitude dependent (due to nonlinearity in dynamic experiments). To evaluate the material's integrity, one needs to learn about microscopic defects which are at the origin of fracture process in materials. Thus non linear indicators y could be extracted from quantification of the amplitude dependence of non linear phenomena where power laws y = axb are found to be well fitting this kind of behavior. Several experiments on damage evolution show a wide range of variation of the exponent b of the power law going from 1 up to 3 when y is defined as a dimensionless quantity. Using multi-scale multi-state models to describe microscopic mechanisms expected to take place in such systems, we aim to link the variations of b to the micro-structure, that is to say, to the involved mechanism.

Idjimarene, S.; Scalerandi, M.; Bentahar, M.

2014-02-01

4

One damage law for different mechanisms  

Microsoft Academic Search

We consider here a general three-dimensional kinetic damage law. It uses the thermodynamic of irreversible processes formalism\\u000a and the phenomenological aspects of isotropic damage. It gives the damage rate as a function of its associated variable, the\\u000a strain energy density release rate and the accumulated plastic strain rate.\\u000a \\u000a Associated with different plastic constitutive equations, this damage law takes into account

J. Lemaitre; J. P. Sermage

1997-01-01

5

One damage law for different mechanisms  

NASA Astrophysics Data System (ADS)

We consider here a general three-dimensional kinetic damage law. It uses the thermodynamic of irreversible processes formalism and the phenomenological aspects of isotropic damage. It gives the damage rate as a function of its associated variable, the strain energy density release rate and the accumulated plastic strain rate. Associated with different plastic constitutive equations, this damage law takes into account brittle damage, ductile damage, low and high cycle fatigue and creep damage. In this paper we mainly focus on creep-fatigue interaction and high cycle fatigue. Associated to a viscoplastic constitutive equation having kinematic hardening, the damage law gives the non linear creep-fatigue interaction. The agreement with experiments is good. Associated to plastic constitutive equations also having kinematic hardening but introduced in a micromechanical two scale model based on the self-consistent scheme, it models the non linear accumulation of damage induced by a succession of sequences of different amplitudes as well as the effect of the mean stress and the influence of non proportional loading.

Lemaitre, J.; Sermage, J. P.

1997-07-01

6

Evolution of the Second Law of Thermodynamics  

ERIC Educational Resources Information Center

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)

Raman, V. V.

1970-01-01

7

A Damage Evolution Approach in Fracture Mechanics of Pipelines  

Microsoft Academic Search

\\u000a The paper concentrates on perspectives of the damage evolution approach in fracture mechanics of oil and gas pipelines. This\\u000a approach is based on the generalised concept of damage. It is postulated that deformation and fracture processes in solids\\u000a are determined by some general functional law related to the accumulation of damage. Fracture mechanics parameters are accepted\\u000a as the controlling parameters

Yu. G. Matvienko

8

Probabilistic constitutive law for damage in ligaments  

Microsoft Academic Search

A new constitutive equation is presented to describe the damage evolution process in parallel-fibered collagenous tissues such as ligaments. The model is formulated by accounting for the fibrous structure of the tissues. The tissue’s stress is defined as the average of the collagen fiber’s stresses. The fibers are assumed to be undulated and straightened out at different stretches that are

Zheying Guo; Raffaella De Vita

2009-01-01

9

Probabilistic constitutive law for damage in ligaments.  

PubMed

A new constitutive equation is presented to describe the damage evolution process in parallel-fibered collagenous tissues such as ligaments. The model is formulated by accounting for the fibrous structure of the tissues. The tissue's stress is defined as the average of the collagen fiber's stresses. The fibers are assumed to be undulated and straightened out at different stretches that are randomly defined according to a Weibull distribution. After becoming straight, each collagen fiber is assumed to be linear elastic. Damage is defined as a reduction in collagen fiber's stiffness and occurs at different stretches that are also randomly defined by a Weibull distribution. Due to the lack of experimental data, the predictions of the constitutive equation are analyzed by varying the values of its structural parameters. Moreover, the results are compared with the available stress-strain data in the biomechanics literature that evaluate damage produced by subfailure stretches in rat medial collateral ligaments. PMID:19665914

Guo, Zheying; De Vita, Raffaella

2009-11-01

10

Micro Damage Evolution Analysis of Target Impacted by Projectile  

NASA Astrophysics Data System (ADS)

A new dynamic stress-strain rate type constitutive model for mixed hardening material has been developed using evolutional Gurson type yield function for solving problems of rigid plastic porous materials. During the plastic process of ductile materials in many engineering problems, the failure of materials is mainly induced by the damage behaviors such as the nucleation of micro void, their evolutions and the coalescence. With the aid of some concept of parameters and formulations, such as generalized triaxiality function in stress space, void fraction, effective stress with micro void interaction and void induced effective strain rate, generalized triaxiality ratio and so on, the dynamic void evolutional process of mixed hardening material has been analyzed in detail. Based on the above constitutive law the rigid-plastic finite element modeling and the FEM computer system including the damage evolutional process have been developed. The micro damage phenomena caused by collision of a flying projectile on to a target is simulated in order to reveal the applicability of the method. The inherent relations between the penetration and perforation process, and damage evolution process during the impact of target plate by projectile are revealed.

Tsuta, Toshio; Yin, Yajun; Iwamoto, Takeshi

11

Entropy evolution law in a laser process  

SciTech Connect

For the first time, we obtain the entropy variation law in a laser process after finding the Kraus operator of the master equation describing the laser process with the use of the entangled state representation. The behavior of entropy is determined by the competition of the gain and damping in the laser process. The evolution formula for the number of photons is also obtained. -- Highlights: •We apply the thermo-field dynamics method to the master equation of a laser. •We find the operator-sum (Kraus) representation for the density operator. •We find both the normally ordered and compact forms of ?(t) for ?{sub 0}=|z??z|. •We find the exact expression of the laser’s entropy. •Our results reveal quantitatively how a laser beam can be generated in a laser.

Chen, Jun-hua, E-mail: cjh@ustc.edu.cn; Fan, Hong-yi

2013-07-15

12

Stochastic damage evolution in textile laminates  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

13

Damages for pain and suffering in tort law.  

PubMed

Legislation enacted between 2002 and 2005 by each Australian State and Territory reformed and partially codified the common law of personal injuries. This column examines the nature and history of damages for pain and suffering and analyses the approach taken by different Australian jurisdictions to compensation for non-economic loss. Non-economic loss is generally composed of pain and suffering, loss of amenities of life, and loss of enjoyment of life (some jurisdictions, eg New South Wales, also include disfigurement, and loss of expectation of life). Several jurisdictions have imposed thresholds that a claimant must meet as a prerequisite to suing for damages at common law. PMID:18575167

Mendelson, Danuta

2008-05-01

14

A one-dimensional micromechanical model of elastic-microplastic damage evolution  

Microsoft Academic Search

Summary A one-dimensional micromechanically based model of elastic-microductile damage evolution is presented. The deterioration of the material is represented by Dugdale micro-cracks. Postulating a physically plausible crack growth law a consequent homogenisation predicts the macroscopic hardening and softening behavior during a loading process as well as the corresponding continuous damage evolution and typical characteristics during a final unloading process.

W. Becker; D. Gross

1987-01-01

15

A two-dimensional micromechanical model of anisotropic elastic-microplastic damage evolution  

Microsoft Academic Search

A two-dimensional micromechanically based model of anisotropic elastic-microplastic damage evolution is presented. The deterioration of the material is represented by equally oriented Dugdale microcracks. Assuming a physically plausible crack growth law a consequent homogenization gives the macroscopic nonlinear stress-strain behavior during a loading process as well as the evolution of the corresponding anisotropic damage and typical characteristics during a final

W. Becker; D. Gross

1988-01-01

16

Universe with the linear law of evolution  

Microsoft Academic Search

The model of the homogenous and isotropic universe is considered in which the coordinate system of reference is not defined by the matter but is a priori specified. The scale factor of the universe changes following the linear law. The scale of mass changes proportional to the scale factor. The temperature of the relativistic matter changes inversly proportional to the

D. L. Khokhlov

1998-01-01

17

Universe with the linear law of evolution  

Microsoft Academic Search

The model of the homogenous and isotropic universe is considered in which the\\u000acoordinate system of reference is not defined by the matter but is a priori\\u000aspecified. The scale factor of the universe changes following the linear law.\\u000aThe scale of mass changes proportional to the scale factor. The temperature of\\u000athe relativistic matter changes inversly proportional to the

D. L. Khokhlov

1998-01-01

18

The Evolution of Water Law and Policy in Spain  

Microsoft Academic Search

Spain has old and complex legislation with regard to water, which has recently undergone some modification (the 1999 Act). The water market has been introduced, with emphasis on environmental protection aspects, while continuing traditional management through hydro basins. The current state of evolution in water law is one of vagueness, with contrasting lines of tension; in some, the old type

Antonio Embid

2002-01-01

19

Effects of an Uncertainty on Evolution Law in Dynamical Systems.  

National Technical Information Service (NTIS)

It is shown that a small perturbation of the evolution law of chaotic dynamical systems is practically equivalent to the finite precision on the knowledge of the initial condition. In spite of the short predictability time t sub p on a single trajectory t...

A. Crisanti M. Falcioni A. Vulpiani

1989-01-01

20

The constructal law and the evolution of design in nature.  

PubMed

The constructal law accounts for the universal phenomenon of generation and evolution of design (configuration, shape, structure, pattern, rhythm). This phenomenon is observed across the board, in animate, inanimate and human systems. The constructal law states the time direction of the evolutionary design phenomenon. It defines the concept of design evolution in physics. Along with the first and second law, the constructal law elevates thermodynamics to a science of systems with configuration. In this article we review the more recent work of our group, with emphasis on the advances made with the constructal law in the natural sciences. Highlighted are the oneness of animate and inanimate designs, the origin of finite-size organs on animals and vehicles, the flow of stresses as the generator of design in solid structures (skeletons, vegetation), the universality and rigidity of hierarchy in all flow systems, and the global design of human flows. Noteworthy is the tapestry of distributed energy systems, which balances nodes of production with networks of distribution on the landscape, and serves as key to energy sustainability and empowerment. At the global level, the constructal law accounts for the geography and design of human movement, wealth and communications. PMID:21683663

Bejan, Adrian; Lorente, Sylvie

2011-10-01

21

Scaling laws in evolution of large computer programs  

NASA Astrophysics Data System (ADS)

The approach is based on a paradigm of self-organized criticality 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 the self-organization criticality are found. The model of software evolution presenting the natural selection principle is proposed. The results of numerical and analytical investigation of the model are presented. They are in good agreement with the data collected for the real-world software.

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

2008-05-01

22

Plastic strain induced damage evolution and martensitic transformation in ductile materials at cryogenic temperatures  

NASA Astrophysics Data System (ADS)

The Fe-Cr-Ni stainless steels are well known for their ductile behavior at cryogenic temperatures. This implies development and evolution of plastic strain fields in the stainless steel components subjected to thermo-mechanical loads at low temperatures. The evolution of plastic strain fields is usually associated with two phenomena: ductile damage and strain induced martensitic transformation. Ductile damage is described by the kinetic law of damage evolution (cf. [1]). Here, the assumption of isotropic distribution of damage (microcracks and microvoids) in the Representative Volume Element (RVE) is made. Formation of the plastic strain induced martensite (irreversible process) leads to the presence of quasi-rigid inclusions of martensite in the austenitic matrix. The amount of martensite platelets in the RVE depends on the intensity of the plastic strain fields and on the temperature. The evolution of the volume fraction of martensite is governed by a kinetic law based on the accumulated plastic strain (cf. [2]). Both of these irreversible phenomena, associated with the dissipation of plastic power, are included into the constitutive model of stainless steels at cryogenic temperatures. The model is tested on the thin-walled corrugated shells (known as bellows expansion joints) used in the interconnections of the Large Hadron Collider, the new proton storage ring being constructed at present at CERN. .

Garion, C.; Skoczen, B. T.

2002-05-01

23

Digital image correlation and biaxial test on composite material for anisotropic damage law identification  

Microsoft Academic Search

The purpose of the work is to extend the use of non-conventional tests and full field measurements to the identification of an anisotropic damage law. A Digital Image Correlation technique based on a finite element discretization is used to extract planar displacement fields. The reconditioned Equilibrium Gap Method is then used to retrieve a damage law that accounts for shear

Jean Noël Périé; Hugo Leclerc; Stéphane Roux; François Hild

2009-01-01

24

Einstein's evolution equations as a system of balance laws  

SciTech Connect

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.

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

1989-08-15

25

Dollo's law and the re-evolution of shell coiling.  

PubMed Central

Gastropods have lost the quintessential snail feature, the coiled shell, numerous times in evolution. In many cases these animals have developed a limpet morphology with a cap-shaped shell and a large foot. Limpets thrive in marginal habitats such as hydrothermal vents, the high-energy rocky intertidal areas and fresh water, but they are considered to be evolutionary dead-ends, unable to re-evolve a coiled shell and therefore unable to give rise to the diversity seen among coiled snails. The re-evolution of a coiled shell, or any complex character, is considered unlikely or impossible (Dollo's law) because the loss of the character is followed by the loss of the genetic architecture and developmental mechanisms that underlie that character. Here, we quantify the level of coiling in calyptraeids, a family of mostly uncoiled limpets, and show that coiled shells have re-evolved at least once within this family. These results are the first demonstration, to our knowledge, of the re-evolution of coiling in a gastropod, and show that the developmental features underlying coiling have not been lost during 20-100 Myr of uncoiled evolutionary history. This is the first example of the re-evolution of a complex character via a change in developmental timing (heterochrony) rather than a change in location of gene expression (heterotopy).

Collin, Rachel; Cipriani, Roberto

2003-01-01

26

Dynamics of the Size and Orientation Distribution of Microcracks and Evolution of Macroscopic Damage Parameters  

NASA Astrophysics Data System (ADS)

We are dealing with damage of brittle materials caused by growth of microcracks. In our model the cracks are penny-shaped. They can only enlarge but not heal. For a single crack a Rice-Griffith growth law is assumed: There is crack growth only if tension is applied normally to the crack surface, exceeding a critical value. Our aim is to investigate the effect of crack growth on macroscopic constitutive quantities. A possible approach taking into account such an internal structure within continuum mechanics is the mesoscopic theory. A distribution of crack lengths and crack orientations within the continuum element is introduced. Macroscopic quantities are calculated as averages with the distribution function. A macroscopic measure of the progressing damage, i.e., a damage parameter, is the average crack length. For this scalar damage parameter we derive an evolution equation. Due to the unilateral growth law for the single crack, it turns out that the form of this differential equation depends explicitly on the initial crack length distribution. In order to treat biaxial loading, it is necessary to introduce a tensorial damage parameter. We define a second-order tensor damage parameter in terms of the crack length and orientation distribution function.

Papenfuss, Christina; Böhme, Thomas; Herrmann, Heiko; Muschik, Wolfgang; Verhás, Joseph

2007-05-01

27

Damage evolution on different scale levels  

NASA Astrophysics Data System (ADS)

The patterns of multiple fractures in a localized zone at the notch tip of metallic specimens are studied at different stages of static and cyclic loading. Cumulative number-length distributions of microcracks in the localized zone of fracture and amplitude distribution of acoustic emission signals accompanying the development of fracture are calculated. The influence of metal structure and loading conditions on multiple fracture kinetics is considered. The identified common kinetic features of multiple fractures in metallic specimens are used for analyzing both the localized zones of fracture in rocks and the seismic activity accompanying the formation of faults in the Earth's crust. The basic regularities in the kinetics of damage accumulation before fracturing of a specimen are found to be similar to those in the dynamics of seismicity before an earthquake. The physical interpretation of the parameters used for earthquake prediction is suggested.

Botvina, L. R.

2011-10-01

28

Damage evolution ahead of sharp notches under cyclic loading  

Microsoft Academic Search

The evolution of cyclic damage ahead of sharp notches has been investigated experimentally. The results are analyzed in terms of a loading parameter ?Bvm which is derived from averaging the calculated local stress and strain distribution at the notch root over some microstructure related size scale. This loading parameter is suggested to bridge the gap between the stress controlled crack

S. Sähn; M. Schaper; V. B. Pham; B. Wurm; Th. Husert; E. Winschuh; G. Jaeger

1996-01-01

29

Damage evolution in creep bulging of thin sheet metal  

Microsoft Academic Search

The creeping motion of thin sheet metal, damaged by artificial cavities is observed in bulging tests and simulated ‘semi’-analytically. The sheet metal satisfies Norton’s Law for secondary creep and is subjected to a bi-directional stretch. The stretch is produced by creep bulging through elliptical dies with the virtue of sustaining nearly uniform background stress ratio for each aspect ratio of

J. Tirosh; L. Rubinski; A. Shirizly; D. P. Harvey II

2000-01-01

30

Mathematical Modelling of Hydraulic Permeability Evolution in the Damage Zone Surrounding Geological Faults  

NASA Astrophysics Data System (ADS)

Geological faults are planar structures, oriented in three-dimensional space, on which shear displacement has occurred. As the rock shears, the material within and around the shear plane is damaged causing a huge variability in fluid flow properties. Faults can be barriers to flow, conduits, or combinations of the two, and their hydraulic properties vary considerably over both space and time. It is critical for the prediction of both future and historical fluid (or gas) migration through fault zones to be able to assess their spatial and temporal hydraulic evolution. This is particularly relevant, due to the large timescales involved, when modelling historic migration in oil fields, or when simulating the transport of radionuclides following the deep burial of radioactive waste. Fluid flow and structural deformation are fully coupled processes within fault zones: Small scale discontinuities, such as fractures and deformation bands of reduced permeability, are formed in the damage zone surrounding faults and have a strong influence on flow properties. Fluid flow in the subsurface is traditionally modelled using Darcy's law, and structural deformation using Navier's law. The main aim of this research is to investigate and validate our understanding of these coupled processes in the damage zone surrounding faults. In the research presented here, fault zone evolution is modelled using a finite element approach. The coupled hydro-mechanical model has been developed and validated using standard benchmark data. The model has been used to simulate deformation and fluid flow in damage zone structures mapped at the Big Hole fault, Utah. Results demonstrate propagation of the existing slip surfaces leading to increased flow. The model is now being applied to explore temporal and spatial fault evolution in the Sierra Nevada based on data sets collected by Bürgmann and Pollard. Results will validate and enhance scientific understanding of the physical processes inherent in fault development. Ultimately, the model will be extended to include chemical processes such as mineralisation, and will provide an invaluable tool for predicting the heterogeneous hydrogeological properties of faults.

Willson, J. P.; Lunn, R. J.; Cowie, P.

2004-12-01

31

Synchrotron Tomographic Characterization of Damage Evolution During Aluminum Alloy Solidification  

NASA Astrophysics Data System (ADS)

Fast synchrotron X-ray microtomography was used to directly observe damage accumulation in a semi-solid Al-15 wt pct Cu alloy with a solid fraction of ~0.75 during isothermal tensile deformation. The evolution of damage was quantified in terms of size distribution of internal and surface-connected damage, strain mapping, and volume change to provide an insight into hot tear formation. A combination of existing void growth, void nucleation, and void coalescence all contribute to the final failure, although each dominates during different stages of deformation. Specifically, internal voids are shown to grow and coalesce from the region of high triaxiality at the center of the gage length outward and prove to be the contributing factor to final failure caused by insufficient liquid feeding.

Puncreobutr, Chedtha; Lee, Peter D.; Hamilton, Richard W.; Cai, Biao; Connolley, Thomas

2013-12-01

32

The Evolution of Health Care Advance Planning Law and Policy  

PubMed Central

Context: The legal tools of health care advance planning have substantially changed since their emergence in the mid-1970s. Thirty years of policy development, primarily at the state legislative level addressing surrogate decision making and advance directives, have resulted in a disjointed policy landscape, yet with important points of convergence evolving over time. An understanding of the evolution of advance care planning policy has important implications for policy at both the state and federal levels. Methods: This article is a longitudinal statutory and literature review of health care advance planning from its origins to the present. Findings: While considerable variability across the states still remains, changes in law and policy over time suggest a gradual paradigm shift from what is described as a “legal transactional approach” to a “communications approach,” the most recent extension of which is the emergence of Physician Orders for Life-Sustaining Treatment, or POLST. The communications approach helps translate patients’ goals into visible and portable medical orders. Conclusions: States are likely to continue gradually moving away from a legal transactional mode of advance planning toward a communications model, albeit with challenges to authentic and reliable communication that accurately translates patients’ wishes into the care they receive. In the meantime, the states and their health care institutions will continue to serve as the primary laboratory for advance care planning policy and practice.

Sabatino, Charles P

2010-01-01

33

Time evolution of damage due to environmentally assisted aging in a fiber bundle model  

NASA Astrophysics Data System (ADS)

Damage growth in composite materials is a complex process which is of interest in many fields of science and engineering. We consider this problem in a fiber bundle model where fibers undergo an aging process due to the accumulation of damage driven by the locally acting stress in a chemically active environment. By subjecting the bundle to a constant external load, fibers fail either when the load on them exceeds their individual intrinsic strength or when the accumulated internal damage exceeds a random threshold. We analyze the time evolution of the breaking process under low external loads where aging of fibers dominates. In the mean field limit, we show analytically that the aging system continuously accelerates in a way which can be characterized by an inverse power law of the event rate with a singularity that defines a failure time. The exponent is not universal; it depends on the details of the aging process. For localized load sharing, a more complex damage process emerges which is dominated by distinct spatial regions of the system with different degrees of stress concentration. Analytical calculations revealed that the final acceleration to global failure is preceded by a stationary accumulation of damage. When the disorder is strong, the accelerating phase has the same functional behavior as in the mean field limit. The analytical results are verified by computer simulations.

Lennartz-Sassinek, S.; Main, I. G.; Danku, Z.; Kun, F.

2013-09-01

34

Damage evolution in metal matrix composites subjected to thermomechanical fatigue  

SciTech Connect

A thermomechanical analysis of unidirectional continuous fiber metal matrix composites is presented. The analysis includes the effects of processing induced residual thermal stresses, interface cracking, and inelastic matrix behavior on damage evolution. Due to the complexity of the nonlinear effects, the analysis is performed computationally using the finite element method. The interface fracture is modeled by a nonlinear constitutive model. The problem formulation is summarized and results are presented for a four-ply unidirectional SCS-6/{beta}21S titanium composite under high temperature isothermal mechanical fatigue.

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

1995-05-01

35

Functionality, power-laws and defect evolution in software systems  

Microsoft Academic Search

In a previous paper, an intimate link between power-law distri- bution of component sizes and defect growth in maturing software systems, independently of their representation language, was revealed by the use of a variational method built on statistical mechanical ar- guments. Building on the above work, this paper first of all demonstrates ex- perimentally that power-law behaviour in component sizes

Les Hatton

36

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

PubMed Central

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.

Jones, Owen D

2004-01-01

37

Damage evolution during uniaxial compressive tests characterized by acoustic emission monitoring  

Microsoft Academic Search

Damage in rocks under stress is related to cracks nucleation and propagation. Acoustic emissions (AE) are transient elastic wave that are generated by rapid microcracks growth. Hence, the analysis of AE produced during mechanical tests is a non-destructive tool for the study of the rock damage evolution. In order to analyse the damage evolution of pillars in Lorraine iron mines,

J. Wassermann; D. Amitrano; G. Senfaute; F. Homand

2003-01-01

38

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

SciTech Connect

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.

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

2010-01-01

39

Microscopic elasticity and rate and state friction evolution laws  

NASA Astrophysics Data System (ADS)

Rate and state friction formalism represents the dependence of macroscopic shear traction ?M on sliding velocity V and the history of the sliding surface. In macroscopic terms, ?M = PN[?0 + a ln(V/Vref) + b ln(?/?norm)], where PN is normal traction, ?0 is the coefficient of friction, a ? b ? 0.01 are small dimensionless parameters, Vref is a reference velocity, ? is the state variable that depends on history, and ?norm represents the effect of changes in normal traction. This representation does not consider microscopic elasticity and is inadequate over very small times. The apparent value of a just after a small decrease in shear traction is a factor of a few larger than its traditional value of ˜0.01. Changes of microscopic elastic strain energy may cause this effect. Microscopic elasticity affects friction after changes in normal traction. Shear traction does not change instantly after a sudden change in normal traction because time is required for real contact area to change. A hybrid of the aging law (where ?increases linearly with time during holds) and the slip law behavior (where the state variable does not change in the limit of zero sliding velocity) is necessary. Slip-law behavior dominates near steady state and also applies to sudden initial sliding where the state variable and porosity are far from steady state. Porosity increases from its initial value toward the steady state value over slip scaling with the critical displacementDc. The ratio of dilatant to shear strain in low porosity material is a modest fraction of 1 and related to the construct of dilatancy angle in engineering.

Sleep, Norman H.

2012-12-01

40

On-site inspections of pavement damages evolution using GPR  

NASA Astrophysics Data System (ADS)

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'.

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

2014-05-01

41

On a new law of bone remodeling based on damage elasticity: a thermodynamic approach  

PubMed Central

Background Bone tissue is the main element of the human skeleton and is a dynamic tissue that is continuously renewed by bone-resorbing osteoclasts and bone-forming osteoblasts. The bone is also capable of repairing itself and adapting its structure to changes in its load environment through the process of bone remodeling. Therefore, this phenomenon has been gaining increasing interest in the last years and many laws have been developed in order to simulate this process. Results In this paper, we develop a new law of bone remodeling in the context of damaged elastic by applying the thermodynamic approach in the case of small perturbations. The model is solved numerically by a finite difference method in the one-dimensional bone structure of a n-unit elements model. Conclusion In addition, several numerical simulations are presented that confirm the accuracy and effectiveness of the model.

2012-01-01

42

The evolution of the damage zone with fault growth in sandstone and its multiscale characteristics  

Microsoft Academic Search

We document the formation and evolution of the damage zones associated with strike-slip faults in porous sandstone, through detailed field and statistical studies of faults of increasing slip magnitudes. The faults initiate as sheared joints with discontinuous damage zone located primarily at fault tips and fault surface irregularities. With increasing slip, the damage zone develops by progressive fracture infilling and

Ghislain de Joussineau; Atilla Aydin

2007-01-01

43

Effects of microstructure evolution on damage accumulation in lead-free solder joints  

Microsoft Academic Search

The wear out of lead-free solder joints under realistic loading conditions has been shown to deviate strongly from predictions based on current damage accumulation models. We argue that the deviation must be due to the simultaneous evolution of solder properties and damage. In general, solder properties and fatigue behaviors are determined by microstructure and damage accumulation mechanisms. Literature has reported

Linlin Yang; Liang Yin; Brian Roggeman; Peter Borgesen

2010-01-01

44

Rupture propagation and radiation : comparisons between interface constitutive laws including damage and friction  

NASA Astrophysics Data System (ADS)

Seismic rupture of large earthquakes propagates along pre-existing faults that have a complex internal structure (fault zone). The propagation and the radiation of a seismic rupture has long been considered in seismology as a friction dominated process, formulated as a propagating shear crack problem under the assumption of a Barenblatt-type surface energy. Simple friction laws, such as the slip weakening and the rate-and-state laws are commonly used in modeling the rupture process, because they well describe the low frequency content of near-fault strong motion data, whilst they insure finite stress and slip velocity at the rupture tip through the introduction of a characteristic cohesive length scale. The high frequency signal data provided by the rapidly increasing quality and density of the seismological and geodetic data in the near fault region should provide new informations on smaller scale features of the rupture which require to go beyond the classical frictional shear crack paradigm. At the same time, the rapid development of new sophisticated and efficient numerical methods is providing us with tools for simulation of rupture propagation and high frequency radiation. In this study, we first provide a short description of recent development of numerical methods based on non smooth contact mechanics and high-order variational approximation of the elastodynamics, together with non classical interface constitutive laws (Raous et al, 1999) that account for interface damage and breakdown processes as well as loading/unloading response generalizing the classical smooth linear slip-weakening friction law. We investigate here the characteristics of the nucleation, propagation, arrest and high frequency radiation for planar and complex fault geometries and compare them to the features provided by standard friction law, such as slip weakening and rate-and-state laws. We finally investigate the effects related to off-fault dissipation in terms of volumetric dynamical damage, and its potential implication for the scaling of the radiated energy, for different fault geometries. Finally, we discuss some open issues regarding the multi-scale modeling of earthquake rupture dynamics, and high frequency generation, when retaining a formulation based on surface energy.

Vilotte, J.; Festa, G.; Raous, M. R.; Henninger, C.

2009-12-01

45

Stress-weakening effect on friction and a major revision of evolution law for contact state  

NASA Astrophysics Data System (ADS)

Rate and State Friction (RSF) law comprehensively captures important aspects of rock friction and has explained various aspects of fault motion successfully. However, existing RSF laws are clearly incorrect in describing some aspects of friction firmly established by experiments [Beeler et al., 1994]. The shortfall is that the state evolution law which aptly represents time-dependent strengthening of virtually locked faults systematically mispredicts the slip distance required to complete the state evolution caused by changed slip velocity [Marone, 1998; Nakatani, 2001]. To address the problem of evolution law, we observed state variable in RSF continuously in friction experiments on rough granite surfaces. The observation of state variable was performed in the following two independent ways; 1) by subtracting direct effect from measured shear stress 2) by using an acoustic monitoring technique [Nagata et al., 2008]. The latter method is usable even when slip velocity is so low that the former method cannot be used. The former can be regarded as “semi-direct” measurements of state variable. This method strongly depends on the value of coefficient of direct effect a. Ideally, a is observed as the instantaneous change of applied shear stress (direct effect) upon velocity step. However, the measured shear stress change is much smaller than the real direct effect in reality because the state variable changes considerably before the stress peak. Correction by inferring the change of state using an evolution law is a routine procedure, but the evolution law is in doubt. Hence, before we tackled the evolution law issue, we have designed a special step test where the change of state is minimal and have established that a >0.03. Further, with help of acoustic method, we have identified that a ~0.05. The value is surprisingly large, but agrees very well with the activation volume of silicate lattice. We compared thus observed variation of frictional strength with the prediction of a popular version of evolution law called “ageing law” [Dieterich, 1979; Ruina, 1983; Beeler, 1994], which explicitly involves both time-dependent healing and slip-dependent weakening. The comparison has shown that an additional shear-stress-dependent weakening term is needed for ageing law to well reproduce the observed variation of frictional strength. Additional independent support for the existence of stress-dependent weakening was obtained from acoustic observation in experiments carefully designed to suppress effects other than shear stress. In further detail, we have observed by acoustic method that the effect diminishes at lower shear stress. Simulations using the modified ageing law reproduced both shear stress and state variable quantitatively well with the same set of parameter values for various types of experiments, which was actually not possible with the original ageing law. Furthermore, the modified law predicts nearly symmetric response to velocity step up and down, as well as it predicts the completion of slip-weakening in a nearly fixed slip distance irrespective of the initial value of state variable; the two major deficits known for the original ageing law has been dissolved.

Nagata, K.; Nakatani, M.; Yoshida, S.

2009-12-01

46

A computational approach to the investigation of impact damage evolution in discontinuously reinforced fiber composites  

NASA Astrophysics Data System (ADS)

A micromechanical damage constitutive model for discontinuous fiber-reinforced composites is developed to perform impact simulation. Progressive interfacial fiber debonding and a crack-weakened model are considered in accordance with a statistical function to describe the varying probability of damage. Emanating from a constitutive damage model for aligned fiber-reinforced composites, a micromechanical damage constitutive model for randomly oriented, discontinuous fiber-reinforced composites is developed. The constitutive damage model is then implemented into a finite element program DYNA3D to simulate the dynamic behavior and the progressive damage of composites. Finally, numerical simulations for a biaxial loading test and a four-point bend impact test of composite specimens are performed to validate the computational model and investigate impact damage evolution in discontinuous fiber-reinforced composite structures. Furthermore, in order to address the influence of Weibull parameter So on the damage evolution in composites, parametric analysis is carried out.

Lee, H. K.

47

Software and business methods patents: Case law evolution and market strategies  

Microsoft Academic Search

In this paper we explore the evolution of the software industry and the increasing importance of patent protection. Through a set of case law, we show that the various American Courts of Justice for the one hand and the European Patent Office (EPO) one the other hand have the same point of view by granting software patents. We put in

Isabelle Liotard

2006-01-01

48

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

NASA Astrophysics Data System (ADS)

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.

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

2008-12-01

49

von Baer's law for the ages: lost and found principles of developmental evolution.  

PubMed

In 1828, Karl Ernst von Baer formulated a series of empirically defined rules, which became widely known as the 'Law of Development' or 'von Baer's law of embryology'. This was one the most significant attempts to define the principles that connected morphological complexity and embryonic development. Understanding this relation is central to both evolutionary biology and developmental genetics. Von Baer's ideas have been both a source of inspiration to generations of biologists and a target of continuous criticism over many years. With advances in multiple fields, including paleontology, cladistics, phylogenetics, genomics, and cell and developmental biology, it is now possible to examine carefully the significance of von Baer's law and its predictions. In this review, I argue that, 185 years after von Baer's law was first formulated, its main concepts after proper refurbishing remain surprisingly relevant in revealing the fundamentals of the evolution-development connection, and suggest that their explanation should become the focus of renewed research. PMID:24120296

Abzhanov, Arhat

2013-12-01

50

Exploring the effect of power law social popularity on language evolution.  

PubMed

Abstract We evaluate the effect of a power-law-distributed social popularity on the origin and change of language, based on three artificial life models meticulously tracing the evolution of linguistic conventions including lexical items, categories, and simple syntax. A cross-model analysis reveals an optimal social popularity, in which the ? value of the power law distribution is around 1.0. Under this scaling, linguistic conventions can efficiently emerge and widely diffuse among individuals, thus maintaining a useful level of mutual understandability even in a big population. From an evolutionary perspective, we regard this social optimality as a tradeoff among social scaling, mutual understandability, and population growth. Empirical evidence confirms that such optimal power laws exist in many large-scale social systems that are constructed primarily via language-related interactions. This study contributes to the empirical explorations and theoretical discussions of the evolutionary relations between ubiquitous power laws in social systems and relevant individual behaviors. PMID:24730762

Gong, Tao; Shuai, Lan

2014-01-01

51

Evolution Equation of Creep Damage Under Stress Variation  

Microsoft Academic Search

Design and assessment of structural components at elevated temperature are very significant for ensuring the safety. Lear\\u000a damage accumulation (summation of creep time fraction) is widely used to predict creep rupture time under stress and temperature\\u000a variation. Life prediction of creep under stress variation by creep damage mechanics of Kachanov-Rabotnov concides with that\\u000a of linear damage accumulation model. However, creep

Yukio Sanomura; Kzutaka Saitoh

52

Plastic strain induced damage evolution and martensitic transformation in ductile materials at cryogenic temperatures  

Microsoft Academic Search

The Fe-Cr-Ni stainless steels are well known for their ductile behavior at cryogenic temperatures. This implies development and evolution of plastic strain fields in the stainless steel components subjected to thermo-mechanical loads at low temperatures. The evolution of plastic strain fields is usually associated with two phenomena: ductile damage and strain induced martensitic transformation. Ductile damage is described by the

C. Garion; B. T. Skoczen

2002-01-01

53

Plastic Strain Induced Damage Evolution and Martensitic Transformation in Ductile Materials at Cryogenic Temperatures  

Microsoft Academic Search

The Fe-Cr-Ni stainless steels are well known for their ductile behaviour at cryogenic temperatures. This implies development and evolution of plastic strain fields in the stainless steel components subjected to thermo-mechanical loads at low temperatures. The evolution of plastic strain fields is usually associated with two phenomena: ductile damage and strain induced martensitic transformation. Ductile damage is described by the

C Garion; Blazej Skoczen

2001-01-01

54

Modeling stress state dependent damage evolution in a cast Al–Si–Mg aluminum alloy  

Microsoft Academic Search

Internal state variable rate equations are cast in a continuum framework to model void nucleation, growth, and coalescence in a cast Al–Si–Mg aluminum alloy. The kinematics and constitutive relations for damage resulting from void nucleation, growth, and coalescence are discussed. Because damage evolution is intimately coupled with the stress state, internal state variable hardening rate equations are developed to distinguish

M. F. Horstemeyer; J. Lathrop; A. M. Gokhale; M. Dighe

2000-01-01

55

Use of atomic force microscopy for characterizing damage evolution during fatigue  

Microsoft Academic Search

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

Laurent Cretegny

2000-01-01

56

Damage evolution and forming limit predictions of an A12024-T3 aluminium alloy  

Microsoft Academic Search

In this paper, a plastic damage evolution equation for Al2024-T3 sheets is proposed based on the Continuum Damage Mechanics (CDM) and an experimental stress-strain relationship. The forming limit strains of aluminium sheets are predicted based on a modified M-K model which includes the effect of material damage. The theoretical results show that the conventional over-estimations of limit strains in the

W. B. Lee; W. H. Tai; C. Y. Tang

1997-01-01

57

Fatigue crack initiation and damage evolution of unnotched titanium matrix composites  

Microsoft Academic Search

Fatigue crack initiation, multiplication, matrix crack density evolution, and stiffness reduction of several unnotched SCS-6 silicon carbide fiber-reinforced titanium and titanium aluminide matrix composites have been investigated experimentally and analytically. The effects of the thickness of the interfacial reaction layer and fiber coating on fatigue crack initiation life, crack growth rate, and fatigue damage evolution of the composites were examined.

Yung-Chiun Her

1998-01-01

58

Structural damage evolution assessment using the regularised time step integration method  

NASA Astrophysics Data System (ADS)

This paper presents an approach to identify both the location and severity evolution of damage in engineering structures directly from measured dynamic response data. A relationship between the change in structural parameters such as stiffness caused by structural damage development and the measured dynamic response data such as accelerations is proposed, on the basis of the governing equations of motion for the original and damaged structural systems. Structural damage parameters associated with time are properly chosen to reflect both the location and severity development over time of damage in a structure. Basic equations are provided to solve the chosen time-dependent damage parameters, which are constructed by using the Newmark time step integration method without requiring a modal analysis procedure. The Tikhonov regularisation method incorporating the L-curve criterion for determining the regularisation parameter is then employed to reduce the influence of measurement errors in dynamic response data and then to produce stable solutions for structural damage parameters. Results for two numerical examples with various simulated damage scenarios show that the proposed method can accurately identify the locations of structural damage and correctly assess the evolution of damage severity from information on vibration measurements with uncertainties.

Chen, Hua-Peng; Maung, Than Soe

2014-09-01

59

Evolution of damage during deformation in porous granular materials (Louis Néel Medal Lecture)  

NASA Astrophysics Data System (ADS)

'Crackling noise' occurs in a wide variety of systems that respond to external forcing in an intermittent way, leading to sudden bursts of energy release similar to those heard when crunching up a piece of paper or listening to a fire. In mineral magnetism ('Barkhausen') crackling noise occurs due to sudden changes in the size and orientation of microscopic ferromagnetic domains when the external magnetic field is changed. In rock physics sudden changes in internal stress associated with microscopically brittle failure events lead to acoustic emissions that can be recorded on the sample boundary, and used to infer the state of internal damage. Crackling noise is inherently stochastic, but the population of events often exhibits remarkably robust scaling properties, in terms of the source area, duration, energy, and in the waiting time between events. Here I describe how these scaling properties emerge and evolve spontaneously in a fully-dynamic discrete element model of sedimentary rocks subject to uniaxial compression at a constant strain rate. The discrete elements have structural disorder similar to that of a real rock, and this is the only source of heterogeneity. Despite the stationary loading and the lack of any time-dependent weakening processes, the results are all characterized by emergent power law distributions over a broad range of scales, in agreement with experimental observation. As deformation evolves, the scaling exponents change systematically in a way that is similar to the evolution of damage in experiments on real sedimentary rocks. The potential for real-time failure forecasting is examined by using synthetic and real data from laboratory tests and prior to volcanic eruptions. The combination of non-linearity and an irreducible stochastic component leads to significant variations in the precision and accuracy of the forecast failure time, leading to a significant proportion of 'false alarms' (forecast too early) and 'missed events' (forecast too late), as well as an over-optimistic assessments of forecasting power and quality when the failure time is known (the 'benefit of hindsight'). The evolution becomes progressively more complex, and the forecasting power diminishes, in going from ideal synthetics to controlled laboratory tests to open natural systems at larger scales in space and time.

Main, Ian

2014-05-01

60

Matrix Fatigue Damage Evolution in a Longitudinal CFRP Composite  

Microsoft Academic Search

Three point bend tests were conducted on 45o off-axis 60% volume carbon fibre reinforced polymer composites under stress control (stress ratio, R=1) and frequency of 4Hz. This allowed a fundamental study to be carried out on the continuous damage accumulation in the matrix without the influence of delamination. Permanent bending was observed at all stress levels and found to be

A. Plumtree; M. Ostgathe

61

Law  

ERIC Educational Resources Information Center

A case involving the mental health rights of children is currently working its way toward the Supreme Court. That case, Bartley v. Kremens, challenges the power of parents to institutionalize their children in mental hospitals or institutions for the retarded without due process of law. (Author/RK)

Ellis, James W.

1976-01-01

62

Frictional response to velocity steps and 1-D fault nucleation under a state evolution law with stressing-rate dependence  

NASA Astrophysics Data System (ADS)

A new state evolution law has recently been proposed by Nagata et al. (2012) that includes a dependence upon stressing rate through a laboratory derived proportionality constant c. It has been claimed that this law, while retaining the time-dependent healing of the Dieterich (or Aging) law, can also match the symmetric response of the Ruina (or Slip) law to velocity step tests. We show through analytical approximations and numerical results that the new law transitions between the responses of the traditional Aging and Slip laws in velocity step-up/step-down experiments when the value of c is tuned properly. Particularly, for c=0, the response is pure Aging, while for finite, nonzero c one observes Slip law type behavior for small velocity jumps but Aging law type response for larger jumps. The magnitude of the velocity jump required to see this transition between aging and slip behaviors increases as c increases. In the limit of c?1 the response becomes purely Slip law type for all geologically plausible velocity jumps. We also present results from detailed analytical and numerical studies of the mechanism of rupture nucleation on 1-D faults under this new state evolution law to demonstrate that the style of nucleation can also be made to switch from Aging-type (expanding cracks) to Slip-type (slip pulses) by adjusting the value of c as indicated by the velocity step results.

Bhattacharya, P.; Rubin, A. M.

2014-03-01

63

A method for calculating damage evolution in adiabatic shear band of titanium alloy  

Microsoft Academic Search

A method for calculating the evolution of the local damage variable at the adiabatic shear band (ASB) center was proposed. In the present method, the JOHNSON-COOK model and the nonlocal theory were adopted, and the damage variable formula applicable for the bilinear (linearly elastic and strain-softening) constitutive relation was further generalized to consider the plastic deformation occurring in the strain-hardening

Xue-bin WANG

2009-01-01

64

Energy Change due to Off-Fault Damage Evolution associated with Dynamic Fault Tip Growth  

NASA Astrophysics Data System (ADS)

We theoretically study off-fault damage evolution effects on dynamic earthquake rupture, especially from a standpoint of energy change in a whole system. The importance of off-fault inelastic energy loss due to damage on dynamic earthquake rupture has attracted interests of many researchers in terms of, for example, rupture velocity reduction and crack tip growth cessation. The damage effect is found to be important on dynamic earthquake slip behavior in terms of porosity increase also in a series of our previous studies, Suzuki and Yamashita (2007; 2008; 2009; 2010). The mathematical formulation of Murakami and Kamiya (1997) is assumed in the present study; the damage tensor D is used to describe damage state in a medium. Damage, which consists of microcracks in a medium, has direction (defined as normal to the crack surface) and the magnitude (crack size), so that a scalar damage variable is insufficient to describe the damage state. We first analytically derive the equation system including the damage tensor and describing energy change in a whole system due to any dynamic elastic and inelastic deformation processes such as macroscopic crack extension and damage evolution. The change in the summation of strain and kinetic energies and damage energy is found to be equal to the summation of energy flowing out of the medium through the boundary and energy turning to heat and irreversibly lost based on the analytical expression; the damage energy is associated with surface energy released by damage evolution. The damage energy is confirmed to be equal to the summation of the loss in strain energy due to change in the elastic moduli and irreversibly lost energy. A mode III crack embedded in a medium causing damage is then assumed to study the off-fault damage effects on dynamic earthquake rupture. Spontaneous crack tip growth with the Coulomb fracture criterion is assumed and in such a case the rupture velocity can be sufficiently smaller than the terminal velocity (the shear wave speed here) because of energy lost by damage evolution. There also exists a feedback mechanism stabilizing the crack tip growth; if the rupture velocity tends to increase, more damage energy is consumed and the growth is suppressed; on the other hand, if the rupture velocity tends to decrease, the amount of damage energy reduces and the crack tip growth is promoted. Ranges appropriate for parameters appearing in our formulation are estimated if we assume that the rupture velocity is at 80~90% of the shear wave speed, which is the value suggested from seismological observations. About 10~20% of the total energy change is consumed by evolving damage in such a case and the effect of off-fault damage cannot be neglected when we consider, for example, the seismic and the radiation efficiencies. It is suggested that we may overestimate those efficiencies if we do not consider the damage energy.

Suzuki, T.

2010-12-01

65

A computational model for predicting damage evolution in laminated composite plates  

SciTech Connect

A model is developed herein for predicting the evolution of interface degradation, matrix cracking, and delamination at multiple sites in laminated continuous fiber composite plates subjected to monotonic and/or cyclic mechanical loading. Due to the complicated nature of the many cracks and their interactions, a multi-scale micro-meso-local-global methodology is deployed in order to model all damage modes. Interface degradation is first modeled analytically on the microscale, and the results are homogenized to produce a cohesive zone model that is capable of predicting interface fracture. Subsequently, matrix cracking in the plies is modeled analytically on the meso-scale, and this result is homogenized to produce ply level damage dependent constitutive equations. The evolution of delaminations is considered on the local scale, and this effect is modeled using a three dimensional finite element algorithm. Results of this analysis are homogenized to produce damage dependent laminate equations. Finally, global response of the damaged plate is modeled using a plate finite element algorithm. Evolution of all three modes of damage is predicted via interfacing all four scales into a single multi-scale algorithm that is computationally tenable for use on a desktop computer. Results obtained herein suggest that this model may be capable of accurately predicting complex damage patterns such as that observed at open holes in laminated plates.

Phillips, M.L.; Yoon, C.; Allen, D.H.

1999-10-01

66

General introduction to microstructural evolution under cascade damage conditions  

SciTech Connect

A short overview of the processes that affect the evolution of the microstructure during irradiation is given. The processes include defect production with an emphasis on the effects of the dynamic cascade events, defect clustering, irradiation-enhanced diffusion, radiation-induced segregation, phase decompositions and phase transformations. A simple model for the description of the development of the defect microstructure in a pure metal during cascade producing irradiation is also outlined which can provide, in principle, defect fluxes required for the description of the microstructural processes such as phase decomposition and irradiation-induced precipitation.

Wiedersich, H.

1993-06-01

67

Mathematical modeling of genome evolution: Where do the power laws come from  

NASA Astrophysics Data System (ADS)

Power law distributions appear in numerous biological, physical, social and other contexts, which appear to be fundamentally different. In biology, power laws have been claimed to describe the distributions of the connections of enzymes and metabolites in metabolic networks, the number of interaction partners of a given protein, the number of members in paralogous families, and other quantities. In network analysis, power laws imply evolution of the network with preferential attachment, i.e. a greater likelihood of nodes being added to pre-existing hubs. Exploration of different types of evolutionary models in an attempt to determine which of them lead to power law distributions has the potential of revealing non-trivial aspects of genome evolution. A simple model of evolution of the domain composition of proteomes was developed, with the following elementary processes: i) domain birth (duplication with divergence), ii) death (inactivation and/or deletion), and iii) innovation (emergence from non-coding or non-globular sequences or acquisition via horizontal gene transfer). This formalism can be described as a birth, death and innovation model (BDIM). The formulas for equilibrium frequencies of domain families of different size and the total number of families at equilibrium were derived for a general BDIM. All asymptotics of equilibrium frequencies of domain families possible for the given type of models were found and their appearance depending on model parameters was investigated. It was proved that the power law asymptotics appears if, and only if, the model is balanced, i.e., domain duplication (birth) and deletion (death) rates are asymptotically equal up to the second order. It was further proved that any power asymptotic with the degree not equal to -1 can appear only if the assumption of independence of the birth/death rates on the size of a domain family is rejected. Specific cases of BDIMs, namely simple, linear, polynomial and rational models, were explored in detail and the distributions of the equilibrium frequencies of domain families of different size were determined for each case. The BDIM formalism was applied to the analysis of the domain family size distributions in prokaryotic and eukaryotic proteomes and an excellent fit was observed between these empirical data and a particular form of the model, the second-order balanced linear BDIM. Calculation of the parameters of these models suggests surprisingly high innovation rates, comparable to the total domain birth (duplication) and death (elimination) rates, particularly for prokaryotic genomes. Thus, a straightforward model of genome evolution, which does not explicitly include selection, seems to be sufficient to explain the observed distributions of domain family sizes, in which power laws appear as asymptotic. However, for the model to be compatible with the data, there has to be a precise balance between domain birth, death and innovation rates, and this is likely to be maintained by selection. The developed approach is oriented at a mathematical description of evolution of domain composition of proteomes, but a simple reformulation could be applied to models of other evolving networks with preferential attachment.

Koonin, Eugene

2003-03-01

68

Laws of Conservation as Related to Brain Growth, Aging, and Evolution: Symmetry of the Minicolumn  

PubMed Central

Development, aging, and evolution offer different time scales regarding possible anatomical transformations of the brain. This article expands on the perspective that the cerebral cortex exhibits a modular architecture with invariant properties in regards to these time scales. These properties arise from morphometric relations of the ontogenetic minicolumn as expressed in Noether’s first theorem, i.e., that for each continuous symmetry there is a conserved quantity. Whenever minicolumnar symmetry is disturbed by either developmental or aging processes the principle of least action limits the scope of morphometric alterations. Alternatively, local and global divergences from these laws apply to acquired processes when the system is no longer isolated from its environment. The underlying precepts to these physical laws can be expressed in terms of mathematical equations that are conservative of quantity. Invariant properties of the brain include the rotational symmetry of minicolumns, a scaling proportion or “even expansion” between pyramidal cells and core minicolumnar size, and the translation of neuronal elements from the main axis of the minicolumn. It is our belief that a significant portion of the architectural complexity of the cerebral cortex, its response to injury, and its evolutionary transformation, can all be captured by a small set of basic physical laws dictated by the symmetry of minicolumns. The putative preservations of parameters related to the symmetry of the minicolumn suggest that the development and final organization of the cortex follows a deterministic process.

Casanova, Manuel F.; El-Baz, Ayman; Switala, Andrew

2011-01-01

69

Computational model for predicting nonlinear viscoelastic damage evolution in materials subjected to dynamic loading  

Microsoft Academic Search

Many inelastic solids accumulate numerous cracks before failure due to impact loading, thus rendering any exact solution of the IBVP untenable. It is therefore useful to construct computational models that can accurately predict the evolution of damage during actual impact\\/dynamic events in order to develop design tools for assessing performance characteristics. This paper presents a computational model for predicting the

Flavio V. Souza; Yong-Rak Kim; George A. Gazonas; David H. Allen

2009-01-01

70

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

NASA Technical Reports Server (NTRS)

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.

Jayaraman, N.

1990-01-01

71

Radiation-induced damage and evolution of defects in Mo  

NASA Astrophysics Data System (ADS)

The formation of defects in bcc Mo lattice as a result of 50-keV Xe bombardment is studied via atomistic simulation with an interatomic potential developed using the force-matching ab initio based approach. The defect evolution in the cascade is described. Diffusion and interaction of interstitials and vacancies are analyzed. Only small interstitial atom clusters form directly in the cascade. Larger clusters grow only via aggregation at temperatures up to 2000 K. Stable forms of clusters demonstrate one-dimensional diffusion with a very high diffusion coefficient and escape quickly to the open surface. Point vacancies have much lower diffusivity and do not aggregate. The possibility of a large prismatic vacancy loop formation near the impact surface as a result of fast recrystallization is revealed. The mobility of the vacancy dislocation loop segments is high, however, the motion of the entire loops is strongly hindered by neighbor point defects. This paper explains the existence of the large prismatic vacancy loops and the absence of the interstitial loops in the recent experiments with ion irradiation of Mo foils.

Starikov, Sergey V.; Insepov, Zeke; Rest, Jeffrey; Kuksin, Alexey Yu.; Norman, Genri E.; Stegailov, Vladimir V.; Yanilkin, Alexey V.

2011-09-01

72

Breaking the Law of Valgus: the surprising and unexplained prevalence of medial patellofemoral cartilage damage  

PubMed Central

Objectives To compare the prevalence of medial and lateral patellofemoral (PF) cartilage damage in three large osteoarthritis (OA) studies and determine the relationship of this damage to varus, neutral, and valgus knee alignment. Methods In the Boston OA of the Knee (BOKS), Framingham OA (FOA), and Multicenter OA (MOST) studies, MRIs were read for cartilage morphology at the medial and lateral patella and trochlea femoris using Whole-Organ MRI Scores (WORMS). WORMS scores ? 2 (any cartilage defect), ? 3 (areas of partial thickness loss), ? 4 (diffuse partial thickness loss), and ? 5 (extensive full thickness loss) were all variously considered as thresholds to identify damage that may indicate OA. Full-limb radiographs were measured for mechanical alignment, and varus (< ?2°), neutral (?2° to 2°), and valgus (> 2°) knees were identified. Results The prevalence of medial PF cartilage damage exceeded that of lateral damage in all three OA studies and according to nearly every threshold. Only among severely involved knees (WORMS ? 4 or ? 5) did the prevalence of lateral PF cartilage damage approximate that of medial damage. The high prevalence of medial PF damage persisted in all strata of knee alignment. Even among knees with valgus malalignment, the prevalence of lateral PF cartilage damage equaled or surpassed that of medial PF damage only when the threshold was specific to severely involved knees. Conclusions Medial PF cartilage damage is at least as prevalent among older adults as lateral PF cartilage damage.

Gross, K. Douglas; Niu, Jingbo; Stefanik, Joshua J.; Guermazi, Ali; Roemer, Frank W.; Sharma, Leena; Nevitt, Michael C.; Segal, Neil A.; Lewis, Cora E.; Felson, David T.

2013-01-01

73

Evolution Law of the Optical Field of Degenerate Parametric Amplifier in Dissipative Channel  

NASA Astrophysics Data System (ADS)

We explore the time-evolution law of the optical field of degenerate parametric amplifier (DPA) in dissipative channel. It turns out that its density operator at initial time ? 0 = A exp(E ? a †2) exp(a † aln?) exp(E a 2) evolves into ? (t)= {A}/{? ^' }} exp ({E^{ast }e^{-2kappa t}a^{dag 2}}/{ ? ^' 2}})exp {a^{dag }aln {[? -(? 2-4|E|2)T]e^{-2?t}/}{? ^' 2}}} exp ({ Ee^{-2? t}a2}/{? ^' 2}}), where ? is the damping constant of the channel, T = 1 - e -2?t , and ? ^' }? ?{(1-? T)2-4|E|2T2}. We employ the method of integration (or summation) within an ordered (normally ordered or antinormally ordered) of operators to overcome the obstacles in the process of calculation.

Chen, Feng; Fang, Bao-long; He, Rui; Fan, Hong-yi

2014-04-01

74

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

NASA Astrophysics Data System (ADS)

A higher-order hydrodynamics for material motion in fluids, under arbitrary nonequilibrium conditions, is constructed. We obtain what is a generalized-to that conditions-Fick-type Law. It includes a representation of Burnett-type contributions of all order, in the form of a continuous-fraction expansion. Also, the equation includes generalized thermodynamic forces, which are characterized and discussed. All kinetic coefficients are given as correlations of microscopic mechanical quantities averaged over the nonequilibrium ensemble, and then are time- and space-dependent as a consequence of accounting for the dissipative processes that are unfolding in the medium. An extended evolution equation for the density of particles is derived, and the conditions when it goes over restricted forms of the type of the telegraphist equation and Fick's diffusion equation are presented.

Jou, David; Casas-Vázquez, José; Madureira, Justino R.; Vasconcellos, Áurea R.; Luzzi, Roberto

2002-01-01

75

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

NASA Astrophysics Data System (ADS)

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.

Bell, Grant A. S.

76

The damage and healing of bone in the disuse state under mechanical and electro-magnetic loadings  

Microsoft Academic Search

The damage behaviour of bone tissues has attracted many interests of scientists and engineers due to it can repair itself. This renewing process is performed by bone remodelling. In the present paper, we establish a mechanism-based damage model to rationalize the damage evolution law of bone under simultaneously applied mechanical and electromagnetic fields. An evolutionary law of bone damage and

Chuan-Yong Qu; Shou-Wen Yu

2011-01-01

77

Analysis of WWER-440 and PWR RPV welds surveillance data to compare irradiation damage evolution  

NASA Astrophysics Data System (ADS)

It is known that for Russian-type and Western water reactor pressure vessel steels there is a similar degradation in mechanical properties during equivalent neutron irradiation. Available surveillance results from WWER and PWR vessels are used in this article to compare irradiation damage evolution for the different reactor pressure vessel welds. The analysis is done through the semi-mechanistic model for radiation embrittlement developed by JRC-IE. Consistency analysis with BWR vessel materials and model alloys has also been performed within this study. Globally the two families of studied materials follow similar trends regarding the evolution of irradiation damage. Moreover in the high fluence range typical of operation of WWER the radiation stability of these vessels is greater than the foreseen one for PWR.

Debarberis, L.; Acosta, B.; Zeman, A.; Sevini, F.; Ballesteros, A.; Kryukov, A.; Gillemot, F.; Brumovsky, M.

2006-04-01

78

Quantification of damage evolution for a micromechanical model of ductile fracture in spallation of copper  

SciTech Connect

Detailed quantitative measurements of damage evolution in an incipiently spalled and recovered 10100 OFHC copper sample of 30 {micro}m grain size are described. The free surface velocity is shown. The total porosity of the sample as a function of distance from the spall plane is reported. The observed and true volumetric size distribution of voids and the observed size distribution of clusters of voids are also calculated and presented.

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

1997-09-01

79

Damage Evolution and Fault reactivation during Stimulation of a Geothermal Reservoir  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

80

Bradford's law in relation to the evolution of a field. A case study of solar power research  

Microsoft Academic Search

Based on the data of growth of literature in the field of solar power, the present paper investigates the stage of evolution at which the scattering of articles over journals is similar to Bradford's curve, i.e. the stage at which Bradford's law is valid. Traces the related changes that take place in the size and elements of the core during

K. C. Garg; Praveen Sharma; Lalita Sharma

1993-01-01

81

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

NASA Astrophysics Data System (ADS)

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.

Morinière, Freddy D.; Alderliesten, René C.; Tooski, Mehdi Yarmohammad; Benedictus, Rinze

2012-12-01

82

MMonCa: An Object Kinetic Monte Carlo simulator for damage irradiation evolution and defect diffusion  

NASA Astrophysics Data System (ADS)

In this work, we introduce the Object Kinetic Monte Carlo (OKMC) simulator MMonCa and simulate the defect evolution in three different materials. We start by explaining the theory of OKMC and showing some details of how such theory is implemented by creating generic structures and algorithms in the objects that we want to simulate. Then we successfully reproduce simulated results for defect evolution in iron, silicon and tungsten using our simulator and compare with available experimental data and similar simulations. The comparisons validate MMonCa showing that it is powerful and flexible enough to be customized and used to study the damage evolution of defects in a wide range of solid materials.

Martin-Bragado, Ignacio; Rivera, Antonio; Valles, Gonzalo; Gomez-Selles, Jose Luis; Caturla, María J.

2013-12-01

83

Dynamic damage evolution in aluminum as a model system for understanding FCC materials in extreme conditions  

NASA Astrophysics Data System (ADS)

Materials play a key role in many emerging technologies. Future technologies in the energy and defense sectors will place huge demands on material performance with respect to stress, strain, temperature, and pressure. These applications require that the response of materials on dynamic (microsecond) time scales be predictable and controllable. Hence, the goal of this research project was to study the extreme environment of shock loaded damage evolution in aluminum as a model system for understanding dynamic response of FCC metals in these environments. Phase one utilized plate impact experiments to study the influence of spatial effects (in the form of microstructural defect distributions) on the dynamic damage evolution process. Samples were soft recovered for shot analysis and comparison to real time laser velocimetry. Results revealed that the length scale of defects controls the failure mechanisms of the microstructure; suggesting defect density and the spatial distribution of defects are critical factors in the deformation process in extreme environments. Phase two studied the influence of kinetic effects (in the form of dynamic tensile loading rate) to reveal time dependence on the dynamic deformation process. Results concluded damage nucleation and growth rates are highly time dependent and can be overdriven as higher tensile loading rates result in extremely short time durations. It was shown that laser velocimetry provides an adequate means for understanding the dynamic damage evolution process when soft recovery of the sample is unavailable. This was shown by comparing laser velocimetry results with data obtained from optical analysis on recovered specimens. The methodology here provides a means to systematically study materials of interest in extreme conditions and provides a pathway for obtaining the relevant physics needed for model development leading to a predictive capability.

Sanchez, Nathaniel Jonathon

84

Damage and fracture evolution in brittle materials by shape optimization methods  

NASA Astrophysics Data System (ADS)

This paper is devoted to a numerical implementation of the Francfort-Marigo model of damage evolution in brittle materials. This quasi-static model is based, at each time step, on the minimization of a total energy which is the sum of an elastic energy and a Griffith-type dissipated energy. Such a minimization is carried over all geometric mixtures of the two, healthy and damaged, elastic phases, respecting an irreversibility constraint. Numerically, we consider a situation where two well-separated phases coexist, and model their interface by a level set function that is transported according to the shape derivative of the minimized total energy. In the context of interface variations (Hadamard method) and using a steepest descent algorithm, we compute local minimizers of this quasi-static damage model. Initially, the damaged zone is nucleated by using the so-called topological derivative. We show that, when the damaged phase is very weak, our numerical method is able to predict crack propagation, including kinking and branching. Several numerical examples in 2 d and 3 d are discussed.

Allaire, Grégoire; Jouve, François; Van Goethem, Nicolas

2011-06-01

85

Similarity Solutions of Creep — Damage Coupled Problems in Fracture Mechanics  

Microsoft Academic Search

The asymptotic solution to Mode III and Mode I crack problems in a creeping solid in the framework of Continuum Damage Mechanics\\u000a is presented. The kinetic law of damage evolution is the Kachanov — Rabotnov equation [1]. The damage parameter is incorporated into the power-law creep constitutive equations. Thus the coupled system of damage\\u000a mechanics — creep theory equations is

L. V. Stepanova; M. E. Fedina

86

Cosmological evolution of Einstein-Aether models with power-law-like potential  

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

87

Engineering and the law-the wages of sin: preventing punitive damages  

Microsoft Academic Search

The author discusses the common themes in several recent cases holding medical device manufacturers liable for punitive damages. He points out that current medical device design and manufacturing standards prevent clearly dangerous products from staying in the marketplace, creating the legal expectation that devices should be risk-free. A court that expects devices to be risk-free may misunderstand the inevitable adverse

1989-01-01

88

26 CFR 1.162-22 - Treble damage payments under the antitrust laws.  

Code of Federal Regulations, 2010 CFR

...that Z Co.'s claim for treble damages was based on a conspiracy to fix and maintain prices with respect to electrical insulators for high-tension power poles. Since the civil action was not based on the same violation of the Federal...

2009-04-01

89

26 CFR 1.162-22 - Treble damage payments under the antitrust laws.  

Code of Federal Regulations, 2010 CFR

...that Z Co.'s claim for treble damages was based on a conspiracy to fix and maintain prices with respect to electrical insulators for high-tension power poles. Since the civil action was not based on the same violation of the Federal...

2010-04-01

90

Jurisdiction and applicable law in cases of damage from space in Europe—The advent of the most suitable choice—Rome II  

NASA Astrophysics Data System (ADS)

Liability for space activities is a much discussed subject and the advent of commercial space operations has only added to its importance. Articles VI and VII Outer Space Treaty, together with Articles II and III Liability Convention, remain the main entry level for state liability for damage arising from private space activities. Few space-faring nations have introduced national space statutes that include a flow down of their international obligations. The European Union (EU) Regulation on the law applicable to non-contractual obligations—hereinafter Rome II Regulation—could harbour developments for liability law in the context of damage resulting from space operations. Space activities were not the main focus of the Regulation but may well turn out to be an interesting spin-off. The Regulation prescribes general rules that will determine the law applicable to damage scenarios where more than one legal system applies. It is important for trans-national tort cases in that it does not limit the rules of applicable law to EU Member States only. This paper focuses on the common rules applicable to damage actions based on torts or other non-contractual obligations as they apply to damage caused by space activities. After an assessment of the relevant international and national law norms, the impact of the Rome II Regulation will be addressed.

Smith, Lesley Jane; Doldirina, Catherine

2010-01-01

91

Use of atomic force microscopy for characterizing damage evolution during fatigue  

NASA Astrophysics Data System (ADS)

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 life exhausted and impedance spectroscopy. Strain controlled fatigue tests were conducted both in high and low cycle fatigue regimes, and interruptions of the fatigue tests allowed characterizing the evolution of the surface upset at various life-fractions. In the low strain amplitude tests on stainless steel (Deltaepsilonpl/2 = 0.0026%), surface damage occurred in the shape of narrow streaks at the interface between martensite laths where reverted austenite was present. The streaks eventually coalesced to form crack nuclei. In high strain amplitude tests (Deltaepsilon pl/2 = 0.049%), fatigue surface damage was essentially dominated by the formation of extrusions. In copper, both low (Deltaepsilonpl/2 = 0.061%) and high (Deltaepsilonpl/2 = 0.134%) strain amplitude tests showed the formation of slip bands (mainly extrusions) across entire grains. Protrusions were present only in copper specimens tested at the high strain amplitude. Crack nucleation in the low strain amplitude tests occurred in both materials at the interface between a region that sustained a high level of deformation and one with little evidence of surface upset. This commonality between these two materials that are otherwise very dissimilar in nature suggests a universal scheme for location of fatigue crack nucleation sites during HCF. A procedure was developed in this study to quantitatively characterize the amount of irreversible surface strain. The proposed formalism is applicable to any material, independently of the type of surface damage, and leads to a criterion for crack nucleation based on physical evidence of surface damage. A correlation between fatigue damage and impedance spectroscopy measurements was shown in copper, in particular during the primary cyclic hardening stage. The measurements were however less sensitive to the development of surface upset that occurred beyond that stage.

Cretegny, Laurent

2000-10-01

92

Damage Evolution in GaN Under MeV Heavy Ion Implantation  

SciTech Connect

Damage evaluation processes in patterned GaN implanted by 3 MeV Au2+ ions were investigated as function of ion fluences and annealing temperatures. Surface swelling was observed by using AFM and the results showed that the swelling height depends on ion fluence and annealing temperature. A four-stage of implantatation-induced damage evolution, including point defects, defect clustering, disordering or amorphization and even decomposition, was found and was contributed to defect formation, accumulation and N bubble formation induced at different level of dpa. Crater-like holes were observed on the surface of GaN implanted at the ion fluence of 2×1016 cm-2, and it is considered as an evidence of N loss and broken bubbles formed during implantation.

Gao, Yuan; Xue, Jianming; Zhang, Dongzheng; Wang, Zilong; Lan, Chune; Yan, Sha; Wang, Yugang; Xu, Fujun; Shen, Bo; Zhang, Yanwen

2009-10-22

93

Damage evolution during uniaxial compressive tests characterized by acoustic emission monitoring  

NASA Astrophysics Data System (ADS)

Damage in rocks under stress is related to cracks nucleation and propagation. Acoustic emissions (AE) are transient elastic wave that are generated by rapid microcracks growth. Hence, the analysis of AE produced during mechanical tests is a non-destructive tool for the study of the rock damage evolution. In order to analyse the damage evolution of pillars in Lorraine iron mines, a small-scale approach has been studied through laboratory investigations. Experiments of fracturation have been performed under uniaxial deformation on iron ore and mudstone from mine of Tressange (Lorraine, France). Loading consists on successive loading-unloading cycles with increasing the axial load until the sample fails. The axial load as well as six strain gauges outputs are collected by an acquisition system. 12 acoustical transducers were coupled around the sample. 8 of them function as receivers and constitute a mini-seimic network, 4 transducers function as transmitters and are dedicated to P wave velocity measurements in axial and radial directions. A fast acquisition system detects, digitizes and stores the acoustic emission data during mechanical test. This system allows us to count AE and to digitize the associated waveforms. Analysis of acoustical parameters such as P-wave velocity, acoustical activity and mechanical parameter such as permanent deformation has been realized for six uniaxial compressive tests. The acoustical activity is concentrated on the last loading phase until the stress pick and during post-pick phase. Those stages correspond especially to the appearance of the permanent strain. Significant P-wave velocity diminution is also observed during this phase along 32 ray path. Those observations (concerning AE activity, P-wave velocity, and permanent strain) can be attributed to microcracks growth and coalescence, and finally to the formation of the failure planes. Study of others acoustical and mechanical parameters also available such as signal energy, maximum amplitude of AE events, Young modulus, volumetric variations (?V/V), provide a better understanding of rock damage process under stress.

Wassermann, J.; Amitrano, D.; Senfaute, G.; Homand, F.

2003-04-01

94

Frequency Analysis of Acoustic Emission Signal to Monitor Damage Evolution in Masonry Structures  

NASA Astrophysics Data System (ADS)

A crucial aspect in damage evaluation of masonry structures is the analysis of long-term behaviour and for this reason fatigue analysis has a great influence on safety assessment of this structures. Acoustic Emission (AE) are very effective non-destructive techniques applied to identify micro and macro-defects and their temporal evolution in several materials. This technique permits to estimate the velocity of ultrasound waves propagation and the amount of energy released during fracture propagation to obtain information on the criticality of the ongoing process. By means of AE monitoring, an experimental analysis on a set of reinforced and unreinforced masonry walls under variable amplitude and static loading has been carried out. During these tests, the AE signals were recorded. The AE signals were analysed using Fast Fourier Transform (FFT) to examine the frequency distribution of the micro and macro cracking. It possible to evaluate the evolution of the wavelength of the AE signal through the two characteristic peak in the AE spectrum signals and the wave speed of the P or S waves. This wavelength evolution can be represent the microcrak and macrocrack evolution in masonry walls. This procedure permits to estimate the fracture dimension characteristic in several loading condition and for several masonry reinforced condition.

Masera, D.; Bocca, P.; Grazzini, A.

2011-07-01

95

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

NASA Astrophysics Data System (ADS)

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.

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

2000-12-01

96

Constraining the Stream Power Law: a novel approach combining a Landscape Evolution Model and an inversion method  

NASA Astrophysics Data System (ADS)

In the past few decades, many studies have been dedicated to our understanding of the interactions between tectonic and erosion and, in many instances, using numerical models of landscape evolution. Among the numerous parameterizations that have been developed to predict river channel evolution, the Stream Power Law, which links erosion rate to drainage area and slope, remains the most widely used. Despite its simple formulation, its power lies in its capacity to reproduce many of the characteristic features of natural systems (the concavity of river profile, the propagation of knickpoints, etc.). However, the three main coefficients that are needed to relate erosion rate to slope and drainage area in the Stream Power Law remain poorly constrained. In this study, we present a novel approach to constrain the Stream Power Law coefficients under the detachment limited mode by combining a highly efficient Landscape Evolution Model, FastScape, which solves the Stream Power Law under arbitrary geometries and boundary conditions and an inversion algorithm, the Neighborhood Algorithm. A misfit function is built by comparing topographic data of a reference landscape supposedly at steady state and the same landscape subject to both uplift and erosion over one time step. By applying the method to a synthetic landscape, we show that different landscape characteristics can be retrieved, such as the concavity of river profiles and the steepness index. When applied on a real catchment (in the Whataroa region of the South Island in New Zealand), this approach provide well resolved constraints on the concavity of river profiles and the distribution of uplift as a function of distance to the Alpine Fault, the main active structure in the area.

Croissant, T.; Braun, J.

2013-11-01

97

Time evolution of electric fields and currents and the generalized Ohm's law  

Microsoft Academic Search

Fundamentally, the time derivative of the electric field is given by the displacement-current term in Maxwell's generalization of Ampère's law, and the time derivative of the electric current density is given by the generalized Ohm's law. The latter is derived by summing the accelerations of all the plasma particles and can be written exactly, with no approximations, in a (relatively

V. M. Vasyliunas

2005-01-01

98

A Damage Mechanics Treatment of Creep Failure in Rock Salt  

Microsoft Academic Search

Recent progress in the formulation of a constitutive model for describing coupled creep and damage development in rock salt is summarized. The constitutive model is based on the assumption that both dislocation slip and creep damage in the form of microcracks with possible wing-tips contribute to the macroscopic inelastic strain rate. The relevant kinetic equations, flow law, and damage evolution

K. S. Chan; S. R. Bodner; A. F. Fossum; D. E. Munson

1997-01-01

99

Damage and microstructure evolution in GaN under Au ion irradiation  

NASA Astrophysics Data System (ADS)

Damage and microstructure evolution in gallium nitride (GaN) under Au+ ion irradiation has been investigated using complementary electron microscopy, secondary ion mass spectrometry and ion-beam analysis techniques. Epitaxially-grown GaN layers (2 µm thick) have been irradiated by 2.0 MeV Au ions to 1.0 × 1015 and 1.4 × 1015 cm-2 at 155 K and to 7.3 × 1015 cm-2 at 200 K. The irradiation-induced damage has been analysed by Rutherford backscattering spectroscopy in a channelling direction (RBS/C). For a better determination of the ion-induced disorder profile, an iterative procedure and a Monte Carlo code (McChasy) are combined to analyse the ion channelling spectra. With increasing irradiation dose, separated amorphous layers develop from the sample surface and near the damage peak region. Formation of large nitrogen bubbles with sizes up to 70 nm is observed in the buried amorphous layer, while the surface layer contains small bubbles with a diameter of a few nanometres due to significant nitrogen loss from the surface. Volume expansion from 3% to 25% in the irradiated region is suggested by cross-sectional transmission electron microscope and RBS/C measurement. The anomalous shape of the Au distributions under three irradiations indicates out-diffusion of Au towards the sample surface. The results from the complementary techniques suggest that nitrogen is retained in the damaged GaN where the crystallinity is preserved. Once the amorphous state is reached in the surface region, GaN starts to decompose and nitrogen escapes from the surface. Furthermore, experimental results show considerable errors in both the disorder profile and the ion range predicted by the Stopping and Range of Ions in Matter code, indicating a significant overestimation of electronic stopping powers of Au ions in GaN.

Zhang, Yanwen; Ishimaru, Manabu; Jagielski, Jacek; Zhang, Weiming; Zhu, Zihua; Saraf, Laxmikant V.; Jiang, Weilin; Thome, Lionel; Weber, William J.

2010-03-01

100

Damage and Microstructure Evolution in GaN under Au Ion Irradiation  

SciTech Connect

Damage and microstructure evolution in gallium nitride (GaN) under Au+ ion irradiation has been investigated using complementary electron microscopy, secondary ion mass spectrometry and ion beam analysis techniques. Epitaxially-grown GaN layers (2-um-thick) have been irradiated by 2.0 MeV Au ions to 1.0 × 1015 and 1.4 × 1015 cm-2 at 155 K and 7.3 × 1015 cm-2 at 200 K. The irradiation-induced damage has been analyzed by Rutherford backscattering spectroscopy in a channeling direction (RBS/C). For a better determination of ion-induced disorder profile, an iterative procedure and a Monte Carlo code (McChasy) are combined to analyze the ion channeling spectra. With increasing irradiation dose, separated amorphous layers develop from the sample surface and near the damage peak region. Formation of large nitrogen bubbles with sizes up to 70 nm is observed in the buried amorphous layer, while the surface layer contains small bubbles with diameter of a few nanometers due to significant nitrogen loss from the surface. Volume expansion from 3% to 25% in the irradiated region is suggested by cross sectional transmission electron microscope and RBS/C measurement. The anomalous shape of the Au distributions under three irradiations indicates out-diffusion of Au toward sample surface. The results from the complementary techniques suggest that nitrogen is retained in the damaged GaN where the crystallinity is preserved. Once the amorphous state is reached in the surface region, GaN starts to decompose and nitrogen escapes from the surface. Furthermore, experimental results show considerable errors in both disorder profile and ion range predicted by the Stopping and Range of Ions in Matter code, indicating a significant overestimation of electronic stopping powers of Au ions in GaN.

Zhang, Yanwen; Ishimaru, Manabu; Jagielski, Jacek; Zhang, Weiming; Zhu, Zihua; Saraf, Laxmikant V.; Jiang, Weilin; Thome, Lionel; Weber, William J.

2010-02-11

101

[The spirit of the law and the laws of the spirit: the evolution of Brazilian legal thought in the realm of mental health].  

PubMed

The article explores the evolution of the Brazilian republic's laws and norms on mental illness during three periods. The first (1890-1910) saw the topic of mental pathology introduced into the State's realm of interest, with the main concern being to recognize and preserve the rights of those displaying such pathologies. During this period, mental alterations were understood in terms of neuropathology. The following period (1911-1945) saw expansion of government initiatives, with the same concerns as the previous period. The interpretation of mental illness did not undergo any major changes, although it broadened in scope. Marked by a discontinuity in relation to previous times, Brazil's developmentalist period (1946-1982) saw an economic developmentalist spirit hold sway, underpinned by humanist thought of conservative propensity. It brought a vigorous growth in the number of Brazilian hospitals, while interest in protecting the mentally ill continued. PMID:19241674

Messas, Guilherme Peres

2008-01-01

102

Tool Life Prediction for Ceramic Tools in Intermittent Turning of Hardened Steel Based on Damage Evolution Model  

NASA Astrophysics Data System (ADS)

Al2O3-based ceramic is one of the most widely used materials for tools employed in hardened steel turning applications due to its high hardness, wear resistance, heat resistance and chemical stability. The objective of this work is to predict the lives of Al2O3-(W, Ti)C ceramic tools in intermittent turning of hardened AISI 1045 steel by means of damage evolution model taking into account the mechanical loading and thermal effect in the cutting process. A damage evolution model analyzing the RVE with uniformly distributed interacting cracks is constructed based on micromechanics. The calculated results of the proposed damage evolution model are compared with the lives of two kinds of Al2O3-(W, Ti)C ceramic tools obtained through experiments. It is found that the proposed model can be used to predict the lives of the ceramic cutting tools in intermittent turning operation.

Cui, Xiaobin; Zhao, Jun; Zhou, Yonghui; Zheng, Guangming

2011-07-01

103

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

Microsoft Academic Search

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

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

2010-01-01

104

Proposed scaling law for intensity evolution in hadron storage rings based on dynamic aperture variation with time  

NASA Astrophysics Data System (ADS)

A scaling law for the time dependence of the dynamic aperture, i.e., the region of phase space where stable motion occurs, has been proposed in previous papers [M. Giovannozzi, W. Scandale, and E. Todesco, Part. Accel. 56, 195 (1996)PLACBD0031-2460; M. Giovannozzi, W. Scandale, and E. Todesco, in Proceedings of the 1997 Particle Accelerator Conference, edited by M. Comyn, M. K. Craddock, M. Reiser, and J. Thomson (IEEE Service Center, Piscataway, NJ, 1997), p. 1445; M. Giovannozzi, W. Scandale, and E. Todesco, Phys. Rev. EPLEEE81063-651X 57, 3432 (1998)10.1103/PhysRevE.57.3432]. This law, based on the analysis of numerical simulations data, is not entirely phenomenological, but motivated by some fundamental theorems of the theory of dynamical systems and indicates that the dynamic aperture has a logarithmic dependence on time. This result is used in turn as a basis for deriving a scaling law for the intensity evolution in hadron storage rings. This relationship is presented and discussed in detail in this paper. Furthermore, experimental data were compared to the predictions of this law and showed a remarkable agreement.

Giovannozzi, M.

2012-02-01

105

Characterization of damage evolution in an AM60 magnesium alloy by computed tomography  

SciTech Connect

Lawrence Livermore National Laboratory (LLNL) and Sandia National Laboratories, California (SNL) are collaborating on the development of new techniques to study damage evolution and growth in material specimens subjected to mechanical loading. These techniques include metallography, radiography, computed tomography (CT) and modeling. The material specimens being studied include cast magnesium and aluminum alloys, and forged stainless steel. We will concentrate on characterizing monotonically loaded magnesium alloy specimens using computed tomography. Several notched tensile specimens were uniaxially loaded to different percentages of the failure load. Specimens were initially characterized by radiography and computed tomography to determine the preloaded state. Subsequent CT scans were performed after the samples were loaded to different percentages of the load failure. The CT volumetric data are being used to measure void size, distribution and orientation in all three dimensions nondestructively to determine the effect of void growth on the mechanical behavior of the materials.

Waters, Amy; Green, Robert [Center for Nondestructive Evaluation, 3400 N. Charles St., Baltimore, Maryland 21218 (United States); Martz, Harry; Dolan, Ken; Rikard, Derrill [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States); Horstemeyer, Mark [Sandia National Laboratories, 7011 East Ave., Livermore, California 94550 (United States)

1999-12-02

106

Characterization of damage evolution in an AM60 magnesium alloy by computed tomography  

SciTech Connect

Lawrence Livermore National Lab and Sandia National Laboratories, CA are collaborating on the development of new techniques to study damage evolution and growth in material specimens subjected to mechanical loading. These techniques include metallography, radiography, computed tomography (CT) and modeling. The material specimens being studied include cast magnesium and aluminum alloys, and forged stainless steel. The authors concentrate on characterizing monotonically loaded Mg alloy specimens using CT. Several notched tensile specimens were uniaxially loaded to different percentages of the failure load. Specimens were initially characterized by radiography and computed tomography to determine the preloaded state. Subsequent CT scans were performed after the samples were loaded to different percentages of the load failure. The CT volumetric data are being used to measure void size, distribution and orientation in all three dimensions nondestructively to determine the effect of void growth on the mechanical behavior of the materials.

Waters, A.; Green, R.E.; Martz, H.; Dolan, K.; Horstemeyer, M.; Derrill, R.

1999-06-16

107

Modeling ductile metals under large strain, pressure and high strain rate incorporating damage and microstructure evolution  

NASA Astrophysics Data System (ADS)

In this work, a constitutive modeling that couples plasticity, grain size evolution (due to plastic deformation and dynamic recrystallization) and ductile damage has been developed. The effect of grain size on the material yield stress (Hall-Petch) and on the melting temperature has been considered. The model has been used to investigate computationally the behavior of high purity copper in dynamic tensile extrusion test (DTE). An extensive numerical simulation work, using implicit finite element code with direct integration, has been performed and the results have been compared with available experimental data. The major finding is that the proposed model is capable to predict most of the observed features such as the increase of material ductility with the decreasing average grain size, the overall number and size of fragments and the average grain size distribution in the fragment trapped into the dime.

Iannitti, Gianluca; Bonora, Nicola; Ruggiero, Andrew; Dichiaro, Simone

2012-03-01

108

On the nonlinear self-adjointness and local conservation laws for a class of evolution equations unifying many models  

NASA Astrophysics Data System (ADS)

In this paper we consider a class of evolution equations up to fifth-order containing many arbitrary smooth functions from the point of view of nonlinear self-adjointness. The studied class includes many important equations modeling different phenomena. In particular, some of the considered equations were studied previously by other researchers from the point of view of quasi self-adjointness or strictly self-adjointness. Therefore we find new local conservation laws for these equations invoking the obtained results on nonlinearly self-adjointness and the conservation theorem proposed by Nail Ibragimov.

Freire, Igor Leite; Santos Sampaio, Júlio Cesar

2014-02-01

109

Study on Law of Groundwater Evolution under Natural and Artificial Forcing with Case study of Haihe River Basin  

NASA Astrophysics Data System (ADS)

The evolution of groundwater is one of the key problems of water cycle study. It is a result of joint effect of natural condition and human activities, but until now the driving forces of groundwater system evolution were not fully understood due to the complexity of groundwater system structures and the uncertainty of affecting factors. Geology, precipitation and human activity are the main factors affecting the groundwater system evolution and interact each other, but the influence of such three factors on groundwater system are not clarified clearly on a macroscopic scale. The precipitation changes the volume of water recharge and the groundwater pumping effect the discharge of groundwater. Another important factor influencing balance of groundwater storage is the underlaying that affects the renewablility of groundwater. The underlaying is decided mainly by geological attributes but also influenced by human activited. The macroscopic environment of groundwater evolves under the natural and anthropic factors. This paper study the general law of groundwater evolution among the factors based on the case study in Haihe River Basin, a typical area with dramatic groundwater change under natural precipitation attenuation and gradually increase of water suuply. Haihe River Basin is located in north-China, covers an area of 320,041 km2 with over 40% plain areas. The plain area of Haihe Basin is densely populated with many large and medium-sized cities, including metropolis of Beijing and Tianjin, and concentrated irrigated areas, playing important roles in China's economy and food production. It is the unique basin where groundwater occupies majority of total water supply in China. Long-term groundwater over-exploitation causes a series of ecological and environmental problems that threats the sustainable development. In this paper, the historical process of groundwater balance in Haihe Basin is divided into three phases by decrease of rainfall and increase of water pumping. The different problems caused by groundwater shrinkage are summarized. The volume of recharge from natural precipitation and artificial water cycle, natural evaporation and groundwater exploitation are analyzed based on water balance. Through the historical data analysis the changing trend of coefficients of groundwater balance discovers the evolution of groundwater. The general law is concluded with deeper analysis displays the contribution of natural and artificial factors causing deterioration of groundwater balance. A general law of groundwater evolution is put forward to describe the affection of both natural and anthropogenic factors with a relation curve. Considering the water demand of future socio-economic development in Haihe River Basin, the prospective of future vision of groundwater cycle is analyzed by the law of groundwater evolution. Iterated scenario analysis based on comparison of ameliorative function on groundwater balance to point out reasonable control on groundwater exploitation and rational water allocation under the condition of completion of South-to-North Water Transfer Project that could bring more than 7 billion m3 into Haihe River Basin from Yantze River. Finally, the advantages and disadvantages are concluded through the case study and the farther research in this field is pointed out.

You, Jinjun; Gan, Hong; Wang, Lin; Bi, Xue; Du, Sisi

2010-05-01

110

The Evolution of Criminal Law and Police during the Pre-modern Era  

Microsoft Academic Search

Increased standardization was a by-product of technical innovations during the Industrial Revolution. An unfortunate side effect of standardization was enhanced opportunities for theft and embezzlement. Two significant modern institutions radically evolved during the eighteenth to mid-nineteenth centuries to control these growing problems: criminal law and public police. These institutions strongly interacted with the pace of the Industrial Revolution. Our argument

Douglas W. Allen; Yoram Barzel

2009-01-01

111

Evolution and convergence of state laws governing controlled substance prescription monitoring programs, 1998-2011.  

PubMed

Objectives. We sought to collect and characterize all laws governing the operation of prescription monitoring programs (PMPs), state-level databases that collect patient-specific prescription information, which have been suggested as a tool for reducing prescription drug overdose fatalities. Methods. We utilized a structured legal research protocol to systematically identify, review, and code all PMP statutes and regulations effective from 1998 through 2011. These laws were then abstracted along eleven domains, including reporting provisions, data sharing, and data access. Results. PMP characteristics vary greatly among states and across time. We observed an increase in the types and frequency of data required to be reported, the types of individuals permitted to access PMP data, and the percentage of PMPs authorized to proactively identify outlier prescribers and patients. As of 2011, 10 states required PMPs to report suspicious activity to law enforcement, while only 3 required reporting to the patient's physician. None required linkage to drug treatment or required all prescribers to review PMP data before prescribing. Few explicitly address data retention. Conclusions. State PMP laws are heterogeneous and evolving. Future studies of PMP effectiveness should take these variations into account. PMID:24922132

Davis, Corey S; Pierce, Matthew; Dasgupta, Nabarun

2014-08-01

112

Damage Evolution in Composite Materials and Sandwich Structures Under Impulse Loading  

NASA Astrophysics Data System (ADS)

Damage evolution in composite materials is a rather complex phenomenon. There are numerous failure modes in composite materials stemming from the interaction of the various constituent materials and the particular loading conditions. This thesis is concerned with investigating damage evolution in sandwich structures under repeated transient loading conditions associated with impulse loading due to hull slamming of high-speed marine craft. To fully understand the complex stress interactions, a full field technique to reveal stress or strain is required. Several full field techniques exist but are limited to materials with particular optical properties. A full field technique applicable to most materials is known as thermoelastic stress analysis (TSA) and reveals the variation in sum of principal stresses of a cyclically loaded sample by correlating the stresses to a small temperature change occurring at the loading frequency. Digital image correlation (DIC) is another noncontact full field technique that reveals the deformation field by tracking the motion of subsets of a random speckle pattern during the loading cycles. A novel experimental technique to aid in the study of damage progression that combines TSA and DIC simultaneously utilizing a single infrared camera is presented in this thesis. A technique to reliably perform DIC with an infrared (IR) camera is developed utilizing variable emissivity paint. The thermal data can then be corrected for rigid-body motion and deformation such that each pixel represents the same material point in all frames. TSA is then performed on this corrected data, reducing motion blur and increasing accuracy. This combined method with a single infrared camera has several advantages, including a straightforward experimental setup without the need to correct for geometric effects of two spatially separate cameras. Additionally, there is no need for external lighting in TSA as the measured electromagnetic radiation is emitted by the sample's thermal fields. The particular stress resolution of TSA will depend on properties of the material of interest but the noise floor for the temperature variation is universal to the camera utilized. For the camera system in this thesis, the noise floor was found to be fairly frequency independent with a magnitude of 0.01 °C, giving the minimum measurable stress for 2024 aluminum alloy of 3.6 MPa and for Nylon of 0.84 MPa. The average displacement range found during a static DIC test with IR images was 0.1 pixels. The maximum displacement variation at 1 Hz was 0.018 pixels. The average variation in strain at 1 Hz was 25 microstrain comparable to traditional DIC measurements in the visible optical regime. The combined TSA-DIC method in IR was validated with several benchmark example problems including plate structures with holes, cracks, and bimaterials. The validated technique was applied to foam-core sandwich composite beams under repeated simulated wave slamming loading. There are numerous failure modes in sandwich composite materials and the full field stress and strain from TSA and DIC, respectively, allow for improved failure analysis and prediction. Understanding damage in sandwich structures under impulse loading is a complex open area of research and the combined TSA-DIC method provides further insight into the failure process.

Silva, Michael Lee

113

Developing Fitness Functions for Pleasant Music: Zipf's Law and Interactive Evolution Systems  

Microsoft Academic Search

\\u000a In domains such as music and visual art, where the quality of an individual often depends on subjective or hard to express\\u000a concepts, the automating fitness assignment becomes a difficult problem. This paper discusses the application of Zipf’s Law\\u000a in evaluation of music pleasantness. Preliminary results indicate that a set of Zipf-based metrics can be effectively used\\u000a to classify music

Bill Z. Manaris; Penousal Machado; Clayton Mccauley; Juan Romero; Dwight Krehbiel

2005-01-01

114

Damage Evolution and Recovery in Al-Implanted 4H-SiC  

SciTech Connect

Damage evolution in 4H-SiC epitaxial layers irradiated with 1.1 MeV Al molecular ions at 150 K to a range of ion fluences and subsequent isochronal recovery were studied by Rutherford backscattering spectroscopy (RBS) and nuclear reaction analysis (NRA). The relative disorder on both the Si and C sublattices follows a sigmoidal dependence on ion fluence, and a buried amorphous layer is formed when the local dose reaches a critical amorphization value (0.12 dpa). The buried amorphous thickness increases rapidly at {approx} 2.0 x 1014 Al/cm2 and eventually saturates at the highest fluence. Isochronal annealing studies up to 870 K reveals the existence of three distinct recovery stages at {approx} 335, 520 and 650 K for low to intermediate ion fluences, where the relative disorder has not yet reached the fully amorphous level. In high-dose samples, where a buried amorphous layer is produced, the onset of a fourth recovery stage appears above 800 K. Recrystallization occurs at the rear interface and in the surface region, and the relative amount of recovery decreases with increasing fluence for the same annealing temperatures. Defect-stimulated epitaxial growth rather than thermal-stimulated epitaxial growth dominates the recrystallization.

Zhang, Yanwen (EMSL FACILITY USERS); Weber, William J. (BATTELLE (PACIFIC NW LAB)); Jiang, Weilin (BATTELLE (PACIFIC NW LAB)); Hallen, Anders (Royal Institute of Technology); Possnert, Goran (Uppsala University); Y. Yoshida, S. Nishino, H. Harima, and T. Kimoto

2001-12-01

115

High Cycle Fatigue Damage Model for Delamination Crack Growth in CF\\/Epoxy Composite Laminates  

Microsoft Academic Search

This article presents the development of a fatigue damage model which helps to carry out simulation of the evolution of delamination in the laminated composite structures under cyclic loadings. A classical interface damage evolution law, which is commonly used to predict the static debonding process, is modified further to incorporate fatigue delamination effects due to high cycle loadings. An improved

Laurent Gornet; Hassan Ijaz

2011-01-01

116

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)

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.

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

2014-06-01

117

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)

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.

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

2014-04-01

118

An innovative multi-component variate that reveals hierarchy and evolution of structural damage in a solid: application to acrylic bone cement.  

PubMed

A major limitation of solid mechanics is the inability to take into account the influence of hierarchy and evolution of the inherent microscopic structure on evaluating the performance of materials. Irreversible damage and fracture in solids, studied commonly as cracks, flaws, and conventional material properties, are by no means descriptive of the subsequent responses of the microstructures to the applied load. In this work, we addressed this limitation through the use of a novel multi-component variate. The essence of this variate is that it allows the presentation of the random damage in the amplitude spectrum, probability space, and probabilistic entropy. Its uniqueness is that it reveals the evolution and hierarchy of random damage in multi- and trans-scales, and, in addition, it includes the correlations among the various damage features. To better understand the evolution and hierarchy of random damage, we conducted a series of experiments designed to test three variants of a poly (methyl methacrylate) (PMMA) bone cement, distinguished by the methods used to sterilize the cement powder. While analysis of results from conventional tension tests and scanning electron microscopy failed to pinpoint differences among these cement variants, our multi-component variate allowed quantification of the multi- and trans-scale random damage events that occurred in the loading process. We tested the statistical significance of damage states to differentiate the responses at the various loading stages and compared the damage states among the groups. We also interpreted the hierarchical and evolutional damage in terms of the probabilistic entropy (s), the applied stress (?), and the trajectory of damage state. We found that the cement powder sterilization method has a strong influence on the evolution of damage states in the cured cement specimens when subjected to stress in controlled mechanical tests. We have shown that in PMMA bone cements, our damage state variate has the unique ability to quantify and discern the history and evolution of microstructural damage. PMID:22071983

Qi, Gang; Fan, Ming; Lewis, Gladius; Wayne, Steven F

2012-02-01

119

Evolution Law of the Negative Binomial State in Laser Channel and its Photon-Number Decay Formula  

NASA Astrophysics Data System (ADS)

For the first time we examine how a negative binomial state (NBS), whose density operator is {sum }_{n=0}^{infty } {(n+s) !}/{n!s!}? ^{s+1}(1-? )n\\vert nrangle left < n\\vert , evolves in a laser channel. By using a newly derived generating function formula about Laguerre polynomial we obtain the evolution law of NBS, which turns out to be an infinite operator-sum of photon-added negative binomial state with a new negative-binomial parameter, and the photon number of NBS decays with e -2(?-g)t , where g and ? represent the cavity gain and loss respectively. The technique of integration (summation) within an ordered product of operators is used in our discussions.

Da, Cheng; Chen, Qian-Fan; Fan, Hong-Yi

2014-06-01

120

Modeling of the Heterogeneous Damage Evolution at the Granular Scale in Polycrystals under Complex Cyclic Loadings  

Microsoft Academic Search

In this study, a new extension of a micromechanical approach proposed recently by the authors is developed to predict the damaged behavior of polycrystals under various multiaxial cyclic loading paths. The model is expressed in the time dependent plasticity for a small strain assumption. With the framework of the continuum damage mechanics (CDM), it is assumed that a scalar damage

A. Abdul-Latif; M. Chadli

2007-01-01

121

Constraining the Stream Power Law: a novel approach combining a Landscape Evolution Model and an inversion method  

NASA Astrophysics Data System (ADS)

In the past few decades, many studies have been dedicated to our understanding of the interactions between tectonics and erosion. To predict river channel evolution, the Stream Power Law (SPL), which links erosion rate to drainage area and slope (E = KAmSn), remains the most widely used erosion model in the community. Despite its simple formulation, its power lies in its capacity to reproduce many of the characteristic features of natural systems (the concavity of river profile, the propagation of knickpoints, etc.). However, the three main coefficients that are needed to relate erosion rate to slope and drainage area in the SPL remain poorly constrained. In this study, we present a novel approach to constrain the SPL coefficients under the detachment limited mode by combining a highly efficient Landscape Evolution Model, FastScape and an inversion algorithm, the Neighborhood Algorithm. A misfit function is built by comparing topographic data of a reference landscape supposedly at steady state and the same landscape subject to both uplift and erosion over one time step. By applying the method to a synthetic landscape, we show that different landscape characteristics can be retrieved, such as the concavity of river profiles and the steepness index. When applied on a real catchment (in the Whataroa region of the South Island in New Zealand), this approach provides well resolved constraints on the concavity of river profiles and the distribution of uplift as a function of distance to the Alpine Fault, the main active structure in the area.

Croissant, Thomas; Braun, Jean

2014-05-01

122

Radiation damage-He interaction in He implanted Si during bubble formation and their evolution in voids  

NASA Astrophysics Data System (ADS)

He atoms were implanted in crystalline and pre-amorphized silicon wafers at doses in the 2×10 161×10 17 cm-2 range. Using transmission electron microscopy (TEM) we monitored the evolution of He bubbles into voids upon thermal annealing. Bubbles are formed in both crystalline and amorphous silicon. However, in amorphous material bubble interaction with the moving crystalline-amorphous interface during the epitaxial regrowth prevents their evolution into voids. By implanting He at different target temperatures in crystalline Si, thus by changing the structure of radiation damage, we found that the interaction between point defects and He atoms is essential for the generation of He bubbles and for their subsequent evolution into voids.

Raineri, V.; Coffa, S.; Saggio, M.; Frisina, F.; Rimini, E.

1999-01-01

123

Contribution of Strain Hardening Law Coupled to Damage and Remeshing Procedure in the Localization of Plastic Instabilities Application to Hydroforming Processes  

Microsoft Academic Search

In this study, we present an experimental\\/numerical methodology, which aims to improve 3D thin sheet hydroforming considering coupled constitutive equations formulated in the framework of the thermodynamics of irreversible processes accounting for isotropic hardening as well as isotropic ductile damage. The experimental study is dedicated to the identification of stress-strain flow from the global measure of pole displacement, thickness evolution,

Abel Cherouat; Mahfoudh Ayadi; Mohamed Ali Rezgui

2011-01-01

124

[From symmetries to the laws of evolution. I. Chirality as a means of active media stratification].  

PubMed

Features of the hypothetical evolution of a hierarchy of chiral objects formed by active media are discussed. On the basis of experimental facts a new synergetic generalization is made: an evolving system can repeatedly broaden the spectrum of its symmetry types within one level of organization which increases its complexity and change the sign of chirality during transition to a higher level. Switching the chirality sign of macroscopic objects provides irreversibility of stratification. The known chirality of biological structures at different levels suggests that the chiral L/D-stratification should be universal and the hierarchical paths are stable and determined. A high level enantiomorph with reciprocal chirality demonstrates a wider spectrum of functionality. A fractal description of natural hierarchical systems is pointed out to be inadequate because it implicates invariance of the chirality sign of the objects at different scales. PMID:22567922

Tverdislov, V A; Sidorova, A É; Iakovenko, L V

2012-01-01

125

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

PubMed Central

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.

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

2014-01-01

126

Comets and entropy hydrodynamics: How does evolution violate the 2nd law?  

NASA Astrophysics Data System (ADS)

Information density can increase locally if one is careful to control the flow of entropy. Not diffusively but through clever use of "invariants of the flow". Replacing entropy with true invariants of the flow, we show how information can be concentrated or "added" consistent with the observation of increasing complexity on the Earth. Analogous to a digital computer made of fluid components, the "calculation" proceeds by clever manipulation of boundary conditions. Magnetized comets possess exactly the properties needed to produce the simplest entropy invariant, making them a prime candidate for driving evolution. They may also provide the origin of the chirality or "handedness" of life. Thus the Origin-of-life, evolutionary progress paradox can be solved, but at the cost of requiring the universe to be in a highly information-dense initial state.

Sheldon, Robert B.; Webb, Gary

2013-09-01

127

Weak Forms of Shakedown for Elastic–Plastic Structures Exhibiting Ductile Damage  

Microsoft Academic Search

A special weak-form shakedown is studied for elastic–plastic internal-variable material models with nonlinear hardening, damageable elastic moduli and damageable yield surface, in the hypothesis of ductile damage, (i.e. damage induced by plastic strains), but the precise evolutive law of damage being left unspecified. Sufficient weak-form shakedown theorems are presented, one static and another kinematic, each assessing whether eventually plastic deformations

C. Polizzotto; G. Borino; P. Fuschi

2001-01-01

128

Failure of a welded pressure vessel due to creep: damage initiation, evolution and reheat cracking  

Microsoft Academic Search

Continuum damage mechanics (CDM)-based constitutive equations are reviewed and presented for austenitic AISI 316H stainless steels, which undergo creep deformation and damage at 550°C. Two multi-axial stress rupture functions\\/criteria have been utilised. Equations and the finite element computer code, DAMAGE XX, were used to carry out CDM studies of the weldment in an axi-symmetric equivalent of the flank section of

F. Vakili-Tahami; Hayhurst

2007-01-01

129

Experimental measurements of damage evolution in Al-Si eutectic alloys  

SciTech Connect

The application of damage mechanics principles to the study of deformation and fracture of two phase materials, such as metal matrix composites, has recently received much attention. In this context, the primary concern is the initiation and growth of microstructural damage, primarily in the form of particle cracking or interfacial decohesion. It is clear that for many of these materials, microstructural damage initiated at very low imposed strains and has significant effects on the work hardening behavior of the material and the localization process which leads to final fracture. Unfortunately, the quantification of damage is often a difficult and tedious experimental task. It would therefore be of interest to have a simpler method for characterizing damage in these types of systems. The goal of this work was to examine the feasibility of quantifying damage using conventional tension and compression tests. Testing was performed on a model Al-Si eutectic system where the shape and morphology of the second phase could be easily modified to examine situations where high or low levels of damage were expected during deformation. Damage was evaluated by the difference in the compressive and tensile flow stresses as function of applied strain.

Poole, W.J.; Dowdle, E.J. [Univ. of British Columbia, Vancouver, British Columbia (Canada). Dept. of Metals and Materials Engineering] [Univ. of British Columbia, Vancouver, British Columbia (Canada). Dept. of Metals and Materials Engineering

1998-10-05

130

Genetic Basis of a Violation of Dollo's Law: Re-Evolution of Rotating Sex Combs in Drosophila bipectinata  

PubMed Central

Phylogenetic analyses suggest that violations of “Dollo’s law”—that is, re-evolution of lost complex structures—do occur, albeit infrequently. However, the genetic basis of such reversals has not been examined. Here, we address this question using the Drosophila sex comb, a recently evolved, male-specific morphological structure composed of modified bristles. In some species, sex comb development involves only the modification of individual bristles, while other species have more complex “rotated” sex combs that are shaped by coordinated migration of epithelial tissues. Rotated sex combs were lost in the ananassae species subgroup and subsequently re-evolved, ?12 million years later, in Drosophila bipectinata and its sibling species. We examine the genetic basis of the differences in sex comb morphology between D. bipectinata and D. malerkotliana, a closely related species with a much simpler sex comb representing the ancestral condition. QTL mapping reveals that >50% of this difference is controlled by one chromosomal inversion that covers ?5% of the genome. Several other, larger inversions do not contribute appreciably to the phenotype. This genetic architecture suggests that rotating sex combs may have re-evolved through changes in relatively few genes. We discuss potential developmental mechanisms that may allow lost complex structures to be regained.

Seher, Thaddeus D.; Ng, Chen Siang; Signor, Sarah A.; Podlaha, Ondrej; Barmina, Olga; Kopp, Artyom

2012-01-01

131

Coda Wave Interferometry Method Applied in Structural Monitoring to Assess Damage Evolution in Masonry and Concrete Structures  

NASA Astrophysics Data System (ADS)

In this experimental program the main goal is to monitor the damage evolution in masonry and concrete structures by Acoustic Emission (AE) signal analysis applying a well-know seismic method. For this reason the concept of the coda wave interferometry is applied to AE signal recorded during the tests. Acoustic Emission (AE) are very effective non-destructive techniques applied to identify micro and macro-defects and their temporal evolution in several materials. This technique permits to estimate the velocity of ultrasound waves propagation and the amount of energy released during fracture propagation to obtain information on the criticality of the ongoing process. By means of AE monitoring, an experimental analysis on a set of reinforced masonry walls under variable amplitude loading and strengthening reinforced concrete (RC) beams under monotonic static load has been carried out. In the reinforced masonry wall, cyclic fatigue stress has been applied to accelerate the static creep and to forecast the corresponding creep behaviour of masonry under static long-time loading. During the tests, the evaluation of fracture growth is monitored by coda wave interferometry which represents a novel approach in structural monitoring based on AE relative change velocity of coda signal. In general, the sensitivity of coda waves has been used to estimate velocity changes in fault zones, in volcanoes, in a mining environment, and in ultrasound experiments. This method uses multiple scattered waves, which travelled through the material along numerous paths, to infer tiny temporal changes in the wave velocity. The applied method has the potential to be used as a "damage-gauge" for monitoring velocity changes as a sign of damage evolution into masonry and concrete structures.

Masera, D.; Bocca, P.; Grazzini, A.

2011-07-01

132

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

NASA Astrophysics Data System (ADS)

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.

Thostenson, Erik T.; Chou, Tsu-Wei

2008-05-01

133

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

PubMed

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

Thostenson, Erik T; Chou, Tsu-Wei

2008-05-28

134

Penetration and induced damage evolution of concrete and granite when subjected to multiple projectile impacts  

NASA Astrophysics Data System (ADS)

An experimental study was conducted to investigate the penetration process of multiple impacts into concrete targets. The concrete targets were subjected to repeated constant velocity impacts with an ogive nose projectile. The penetration and crater formation data were consistent with single impact penetration data from previous studies conducted at Sandia National Laboratories. In order to predict the depth of the multiple impact penetration, a single impact penetration model, developed by M. Forrestal at Sandia National Laboratories, was extended to account for the degradation of the target strength with each subsequent impact. The degradation of the target was determined empirically and included in the model as a strength-modifying factor. To further understand the multiple impact penetration process, a study was conducted to look at both the static and dynamic properties of concrete and granite as a function of induced damage. Both static and dynamic compression experiments were performed on concrete and granite specimens with various levels of induced damage. The static compressive strength of both materials decreased with increasing levels of damage due to the induced damage causing the activation and propagation of failure cracks in the specimens. In contrast, the dynamic compressive strength remained unchanged with increasing damage due to the inability of the fracture process zone to develop and relieve the strain energy before complete specimen failure. A series of dynamic and static tensile-splitting experiments were performed on concrete and granite specimens to investigate the effect of induced damage on their tensile strength. The experiments showed that the static splitting strength was highly dependent on the orientation of the induced damage with regard to the applied loading, however the dynamic tensile strength decreased with increasing damage with no apparent dependency on the random damage orientation. Photoelastic experiments have shown that the mechanism of failure changes for the dynamically tested damaged specimens, reducing their dependence on damage orientation. The photoelastic experiments also determined that the tensile splitting specimen was in equilibrium at the time of failure, and that the dynamic stress field closely resembles the static splitting stress field.

Gomez, Jason Thomas

135

Modeling of fatigue damage evolution on the basis of the kinetic concept of strength  

Microsoft Academic Search

On the basis of the kinetic theory of strength, a new approach to the modeling of material degradation in cyclic loading has\\u000a been suggested. Assuming that not stress changes, but acting stresses cause the damage growth in materials under fatigue conditions,\\u000a we applied the kinetic theory of strength to model the material degradation. The damage growth per cycle, the effect

Leon Mishnaevsky Jr; Povl Brøndsted

2007-01-01

136

DNA repair and the evolution of transformation in Bacillus subtilis. 3. Sex with damaged DNA  

SciTech Connect

Natural genetic transformation in the bacterium Bacillus subtilis provides an experimental system for studying the evolutionary function of sexual recombination. The repair hypothesis proposes that during transformation the exogenous DNA taken up by cells is used as template for recombinational repair of damages in the recipient cell's genome. Earlier results demonstrated that the population density of transformed cells (i.e., sexual cells) increases, relative to nontransformed cells (primarily asexual cells), with increasing dosage of ultraviolet irradiation, provided that the cells are transformed with undamaged homologous DNA after they have become damaged. In nature, however, donor DNA for transformation is likely to come from cells that are as damaged as the recipient cells. In order to better simulate the effects of transformation in natural populations we conducted similar experiments as those just described using damaged donor DNA. The authors document in this report that transformants continue to increase in relative density even if they are transformed with damaged donor DNA. These results suggest that sites of transformation are often damaged sites in the recipient cell's genome.

Hoelzer, M.A.; Michod, R.E. (Department of Ecology and Evolutionary Biology, University of Arizona, Tucson (USA))

1991-06-01

137

Multiscale Computational Model for Predicting Damage Evolution in Viscoelastic Composites Subjected to Impact Loading.  

National Technical Information Service (NTIS)

The objective of the project was to develop a multiscale computational model capable of predicting the evolution of matrix cracking, delamination, and fiber cracking in viscoelastic composite structures subjected to ballistic impact. The model is three di...

J. N. Reddy

2005-01-01

138

Continuum damage growth analysis using element free Galerkin method  

Microsoft Academic Search

This paper presents an elasto-plastic element free Galerkin formulation based on Newton-Raphson algorithm for damage growth\\u000a analysis. Isotropic ductile damage evolution law is used. A study has been carried out in this paper using the proposed element\\u000a free Galerkin method to understand the effect of initial damage and its growth on structural response of single and bi-material\\u000a problems. Asimple method

C. O. Arun; B. N. Rao; S. M. Srinivasan

2010-01-01

139

Comparing Monofractal and Multifractal Analysis of Corrosion Damage Evolution in Reinforcing Bars  

PubMed Central

Based on fractal theory and damage mechanics, the aim of this paper is to describe the monofractal and multifractal characteristics of corrosion morphology and develop a new approach to characterize the nonuniform corrosion degree of reinforcing bars. The relationship between fractal parameters and tensile strength of reinforcing bars are discussed. The results showed that corrosion mass loss ratio of a bar cannot accurately reflect the damage degree of the bar. The corrosion morphology of reinforcing bars exhibits both monofractal and multifractal features. The fractal dimension and the tensile strength of corroded steel bars exhibit a power function relationship, while the width of multifractal spectrum and tensile strength of corroded steel bars exhibit a linear relationship. By comparison, using width of multifractal spectrum as multifractal damage variable not only reflects the distribution of corrosion damage in reinforcing bars, but also reveals the influence of nonuniform corrosion on the mechanical properties of reinforcing bars. The present research provides a new approach for the establishment of corrosion damage constitutive models of reinforcing bars.

Xu, Yidong; Qian, Chunxiang; Pan, Lei; Wang, Bingbing; Lou, Chi

2012-01-01

140

Fault Damage Zone Characteristics and the Evolution of Fluid Flow Properties  

NASA Astrophysics Data System (ADS)

Faults are a major control on fluid flow in the crust. Fault damage zones are represented by both microfracturing of the rock matrix and by macroscopic fracture networks. The empirical characterization of fracture patterns at various scales, as well as understanding the geometry of the fault zone fracture population help to predict both fault growth processes and bulk hydraulic properties of a fault zone. Here, we characterize the damage around a large strike slip fault zone in order to understand the fluid flow properties and their temporal and spatial variation. We studied faults of various displacements that cut crystalline rock within the excellently exposed and exhumed Atacama Fault Zone, northern Chile. The core zone of the largest displacement fault (~2km offset) displays discrete high strain ultracataclasite layers that bound highly fractured zones of protocataclastic granodiorite. Bulk fluid flow appears to have been largely restricted to this multiple-core zone, as the damage zone displays a lack of hydrothermal activity although fluid inclusion planes indicate early percolation through microcracks. Micro- and macroscale fracture densities within the damage zones of faults with displacements ranging over 3 orders of magnitude (0.2m - 2000m) have been characterized. These show a log-linear decrease in density with perpendicular distance from the fault plane. Macrofractures are a combination of open and shear mode fractures, and are orientated at a high angle to the main fault trace. Microfractures are represented by fluid inclusion planes in a predominantly mode I orientation. Macro and micro-fracture densities fall to background levels at ~50mm for the smallest displacement fault (0.2-2m offset) and ~100m for the two largest faults (200m and 2000m offset). The maximum fracture density of all faults appears to scale with log fault displacement. This differs from other studies where a there is a constant maximum microfracture density that is independent of fault length. Our observations imply that fluid flow in fault damage zones will be controlled by both macroscopic fracture networks and microscopic damage. A paucity in cross-cutting relationships for both macro- and microscopic fracture sets in the damage zone indicates a lack of cyclic damage and implies fluid flow may have been confined to the core zone.

Mitchell, T. M.; Faulkner, D. R.

2005-12-01

141

Locality and nonlocality in geomorphic transport laws: Implications of a particle-based model of hillslope evolution  

NASA Astrophysics Data System (ADS)

Many geomorphic transport laws assume that the transport process is local, meaning that the space and time scales of particle displacement are short relative to those of the system as a whole. This assumption allows one to express sediment flux in terms of at-a-point properties such as the local surface gradient. However, while this assumption is quite reasonable for some processes (for example, grain displacement by raindrop impact), it is questionable for others (such as landsliding). Moreover, particle displacement distance may also depend on slope angle, becoming longer as gradient increases. For example, the average motion distance during sediment ravel events on very steep slopes may approach the length of the entire hillslope. In such cases, the mass flux through a given point may depend not only on the local topography but also on topography some distance upslope, thus violating the locality assumption. Here we use a stochastic, particle- based model of hillslope evolution to gain insight into the potential for, and consequences of, nonlocality in sediment transport. The model is designed as a simple analogy for a host of different processes that displace sediment grains on hillslopes. The hillslope is represented as a two-dimensional pile of particles. These particles undergo quasi-random motion according to the following rules: (1) during each iteration, a particle and a direction are selected at random; (2) the particle hops in the direction of motion with a probability that depends on the its height relative to that of its immediate neighbor; (3) the particle continues making hops in the same direction and with the same probability dependence, until coming to rest or exiting the base of the slope. The topography and motion statistics that emerge from these rules show a range of behavior that depends on a dimensionless relief parameter. At low relief, hillslope shape is parabolic, mean displacement length is on the order of two particle widths, and the probability distribution of displacement length is thin- tailed (approximately exponential). At high relief, hillslopes become planar, average displacement length increases by an order of magnitude, and the displacement-length distribution becomes heavy-tailed (albeit truncated at the slope length). Across the spectrum of relief values, the relationship between mean flux and gradient resembles the family of nonlinear flux-gradient curves that has been used to model hillslope evolution. We compare the emergent morphology and transport statistics with linear, nonlinear, and fractional diffusion models of hillslope transport.

Tucker, G. E.; Bradley, D. N.

2008-12-01

142

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

NASA Astrophysics Data System (ADS)

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.

Kruijssen, J. M. D.

2013-01-01

143

Fault Damage Zone Characteristics and the Evolution of Fluid Flow Properties  

Microsoft Academic Search

Faults are a major control on fluid flow in the crust. Fault damage zones are represented by both microfracturing of the rock matrix and by macroscopic fracture networks. The empirical characterization of fracture patterns at various scales, as well as understanding the geometry of the fault zone fracture population help to predict both fault growth processes and bulk hydraulic properties

T. M. Mitchell; D. R. Faulkner

2005-01-01

144

Evolution of the fi eld of wildlife damage management in the United States and future challenges  

Microsoft Academic Search

Through the early twentieth century, people in rural areas of North America either dealt with problems caused by wildlife by killing the problem species, eliminating its habitat, changing crops or husbandry practices, tolerating the damage, or moving to a new area devoid of such problem animals. However, many of these solutions are impractical today with the increase in human populations,

JAMES E. MILLER

2007-01-01

145

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

Microsoft Academic Search

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

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

2011-01-01

146

Perinatal Hypoxic-Ischemic Brain Damage: Evolution of an Animal Model  

Microsoft Academic Search

Early research in the Vannucci laboratory prior to 1981 focused largely on brain energy metabolism in the developing rat. At that time, there was no experimental model to study the effects of perinatal hypoxia-ischemia in the rodent, despite the tremendous need to investigate the pathophysiology of perinatal asphyxial brain damage in infants. Accordingly, we developed such a model in the

Robert C. Vannucci; Susan J. Vannucci

2005-01-01

147

Effects of Grain Boundary Sliding on Microstructural Evolution and Damage Accumulation in Tin-Lead Alloy  

Microsoft Academic Search

Experiments on the eutectic tin-lead (Sn-Pb) alloys were conducted to study the effects of grain boundary sliding on the deformation and damage processes at the microscopic level. The primary objective is to gain mechanistic undersanding of solder joint reliability in microelectronic packaging. Bulk specimens were subjected to relatively fast deformations of tension, compression, and bending, for the purposes of examining

Y.-L. Shen; K. C. R. Abell; S. E. Garrett

2004-01-01

148

Microscopic evolution of pre-damaged and undamaged tungsten exposed to low-energy and high-flux helium ions  

NASA Astrophysics Data System (ADS)

High-energy (260 keV) He+ pre-damaged and undamaged polycrystalline tungsten samples were irradiated with low-energy (220 eV) and high-flux (˜1021 ions/m2 s) He+ at a sample temperature of 873 K to a fluence of 1.0 × 1025 ions/m2. Microscopic evolution of these samples was carried out using non-destructive conductive atomic force microscopy and a nanohardness test. Analysis indicates that a large number of nanometer-sized protuberances of irradiated tungsten samples results from over-high internal pressure of nanometer-sized helium bubbles. Ordered and nanostructured helium bubbles with the same diameter and average spacing can be formed due to the self-trapping and self-organizing of helium atoms in the tungsten materials. In the case of pre-damaged, low-energy He+ irradiation results in a random distribution of nanostructured helium bubbles, indicating that high-energy He+ implantation results in serious irradiation damage of tungsten materials, acting as nuclei for helium bubbles.

Yang, Qi; Liu, Dongping; Fan, Hongyu; Li, Xin; Niu, Jinhai; Wang, Younian

2014-04-01

149

Characterizing Damage Evolution and Yield in Sandstone Under Triaxial Loading as a Function of Changing Effective Pressure  

NASA Astrophysics Data System (ADS)

Experimental rock deformation was used to study 1) the accumulation of microscopic damage preceding macroscopic failure across the brittle-ductile transition (BDT) in granular porous rocks, 2) how damage induced at one effective pressure (P) affects failure at a different P, and 3) the appropriateness of single yield envelope versus multiple yield envelope models. Granular porous material is idealized as an elastic-plastic material, where failure occurs by localized dilatant shear at low P and compactant cataclastic flow at high P. Given distinct failure modes in the low and high P regimes, different types of damage may develop prior to failure at different P. As such, yielding of porous rocks has been modeled with a single yield envelope, or with two distinct yield envelopes corresponding to the different failure modes. Water saturated cylinders of Berea sandstone (18% porosity, 185 µm grain size) were deformed in triaxial compression at a shortening rate of 4 µm/s. During each experiment, the confining and pore pressure were held constant; acoustic emissions (AE), axial stress, axial displacement, and pore volume changes were recorded. Samples were deformed at pore pressures of 10, 20, and 30 MPa, and confining pressures of 50, 180, and 260 MPa to investigate the brittle, transitional, and ductile regimes. Three different load paths were used. The first involved loading to failure to establish a baseline response. The second involved initial loading to 80% of the differential stress at failure, unloading, and reloading to failure at a different pore pressure. The third was similar to the second, except confining pressure was changed between load and reload to cause failure in a different regime than the initial load. AE is used to quantify damage evolution, and the Kaiser effect was used to map damage states in stress space. The experiments show that contours of equivalent damage are subparallel to the failure envelope across the BDT, and that macroscopic failure depends on load path and the cumulative damage state. Damage induced in either the low or high pressure regimes has little effect for failure in the other deformation regime, supporting the concept of distinct processes and damage development in the two regimes. The behavior across the brittle-ductile transition is most consistent with a model based on two distinct yield envelopes each associated with distinct damage mechanisms and a sharp transition between the low and high pressure regimes. These results could be important in predicting formation damage and permeability changes in over-pressured reservoirs that undergo large drops in pore pressure, as well as for reservoirs undergoing advance recovery methods and sequestration that increase pore pressure. This could also aid in understanding deformation in tectonic basins that experienced P changes due to burial or exhumation, or from cyclic loading along faults.

Choens, R. C.; Chester, F. M.

2009-12-01

150

Constitutive behavior, texture and damage evolution in BCC metal using taylor impact test  

Microsoft Academic Search

To capture the evolution of anisotropy in textured metals under high rate conditions, we developed a method that enables us to digitally resolve this event. Using a Taylor Anvil Test Facility, we dynamically deformed unalloyed Ta, while capturing real time digital images of the radial flow at the impact surface. We measured the elliptical footprint and plotted its eccentricity (ratio

C. P. Trujillo; Gray; S. R. Chen; R. L. Chavez

2004-01-01

151

Modelling of pavement materials on steel decks using the five-point bending test: Thermo mechanical evolution and fatigue damage  

NASA Astrophysics Data System (ADS)

This paper deals with the modelling of wearing courses on steel orthotropic decks such as the Millau viaduct in France. This is of great importance when dealing with durability: due to the softness of such a support, the pavement is subjected to considerable strains that may generate top-down cracks in the layer at right angles of the orthotropic plate stiffeners and shear cracks at the interface between pavement and steel. Therefore, a five-point bending fatigue test was developed and improved since 2003 at the ENTPE laboratory, to test different asphalt concrete mixes. This study aims at modelling the mechanical behavior of the wearing course throughout the fatigue test by a finite element method (Comsol Multiphysics software). Each material - steel, sealing sheet, asphalt concrete layer - is considered and modelled. The modelling of asphalt concrete is complex since it is a heterogeneous material, a viscoelastic medium and it thermosensitive. The actual characteristics of the asphalt concrete (thermo physical parameter and viscoelastic complex modulus) are determined experimentally on cylindrical cores. Moreover, a damage law based on Miner's damage is included in the model. The modelling of the fatigue test leads to encouraging results. Finally, results from the model are compared to the experimental data obtained from the five-point bending fatigue test device. The experimental data are very consistent with the numerical simulation.

Arnaud, L.; Houel, A.

2010-06-01

152

Acute lung injury induced by cadmium aerosol. I. Evolution of alveolar cell damage.  

PubMed Central

Following exposure to an aerosol of 0.1% (.005 M) cadmium chloride, rat lungs were examined at 6 hours and 1, 2, 3, 4, 7, and 10 days. By light microscopy, damage was multifocal and centered about respiratory bronchioles. Ultrastructurally, there was Type 1 cell edema with frequent loss of surface plasma membranes during the first 24 hours. After 2 days, the number of Type 2 cells had markedly increased, and by 3 days the damaged alveoli were lined by plump cuboidal cells closely resembling Type 2 cells. By 4 days, these cells were flatter, the change being more marked by 7 days; by 10 days, the cells had regained the appearance of Type 1 cells through loss of osmiophilic bodies and superficial microvilli. We conclude that CdCl2 damages Type 1 cells, which are then replaced by proliferation of Type 2 cells. These cells lose their osmiophilic bodies and flatten out to replace the lost Type 1 cells, the process being almost complete by 10 days after the injury. This pattern resembles the injury caused by NO2, O3, and O2. Images Figure 16-18 Figure 19 Figures 20-21 Figure 22 Figure 23 Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 24 Figure 25 Figure 26 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15

Strauss, R. H.; Palmer, K. C.; Hayes, J. A.

1976-01-01

153

Effects of He irradiation on Ti3AlC2: Damage evolution and behavior of He bubbles  

NASA Astrophysics Data System (ADS)

In present investigation, Ti3AlC2 ceramic was irradiated at room temperature using 50 keV He ions with doses ranging from 8 × 1016 cm-2 to 1 × 1018 cm-2 and the corresponding peak values of dpa varying from 4 to 52. The damage evolution of nanolaminated crystalline structure as well as the formation and the growth of He bubbles induced by He irradiation were investigated by grazing incidence X-ray diffraction (GIXRD), atomic force microscope (AFM) and transmission electron microscopy (TEM). GIXRD analysis showed serious structural disorder but no obvious amorphization even at the highest dose, which was consistent with the selected area electron diffraction (SAED) results. AFM results demonstrated that serious blistering and exfoliation appeared on the surfaces at high doses. TEM observations revealed the formation of spherical He bubbles, string-like bubbles and "faulting zones" at various doses respectively.

Wang, Chenxu; Yang, Tengfei; Kong, Shuyan; Xiao, Jingren; Xue, Jianming; Wang, Qian; Hu, Chunfeng; Huang, Qing; Wang, Yugang

2013-09-01

154

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

NASA Astrophysics Data System (ADS)

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 with an effective medium approximation. The best fit to the dielectric spectra for disordered silicon could be obtained by taking our highest-fluence implanted (fluence=1×1017 ions/cm2) amorphous silicon (a-Si) data as reference data instead of a-Si data available in the handbook. The derivative spectra as a function of fluence show a distinct and sharp transition from the crystalline to amorphous phase. The threshold fluence for this transition is derived from fitting. Evaluation of standard sum rules and optical moments for imaginary part of the pseudodielectric function reveals no substantial change in various physical parameters below the transition indicating their insensitivity to point defects, while it shows a large change with fluence above the threshold for amorphization. The disorder induced changes in the effective dielectric constant, number of valence electrons per atom participating in optical transition, Penn gap energy, average bond length, coordination number, effective dispersion oscillator energy, an average strength of the interband optical transition with fluence is discussed on the basis of microstructural evolution and corresponding band structure modification. It is also shown that the dielectric functions of damaged silicon are well represented by a sum of six classical Lorentz oscillators. With increasing fluences, each of the oscillator amplitude decreases and linewidth increases except for the 3.3 eV transition which shows increasing amplitude with fluence. These results are discussed in the context of short-range order/disorder and effective band gap reduction along with flattening of the bands with increasing fluence above the amorphization threshold.

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

2001-07-01

155

Spatially resolved stochastic cluster dynamics for radiation damage evolution in nanostructured metals  

NASA Astrophysics Data System (ADS)

A spatially resolved stochastic cluster dynamics (SRSCD) model is introduced to describe radiation-induced defect evolution in metals. The stochastic nature of the method allows SRSCD to model more chemical species and more mobile defects than rate theory methods without loss of computational efficiency, while reaching larger timescales and simulating larger volumes than object-oriented kinetic Monte Carlo (OKMC) methods. To comprehend the capabilities of the method and access new understanding of defect evolution, SRSCD is used in three scenarios. In the first, the results of Frenkel pair implantation are found to match those of rate theory in both spatially homogeneous and spatially resolved media. Next, to study spatial resolution effects and correspondence to OKMC, the results of 20 keV cascade implantation into copper is simulated and an acceptable match with OKMC is found. Finally the method is used to study the problem of helium desorption in thin iron foils. The model is compared with available experimental measures and is found to be in good agreement. The ability of SRSCD to include many mobile species of defects allows a detailed analysis of the mechanisms of helium release from the free surface of the iron foils. As a result new dominant mechanisms of helium release are discussed as well as their operating regimes.

Dunn, Aaron Y.; Capolungo, Laurent; Martinez, Enrique; Cherkaoui, Mohammed

2013-11-01

156

Adaptive Response to DNA-Damaging Agents in Natural Saccharomyces cerevisiae Populations from "Evolution Canyon", Mt. Carmel, Israel  

PubMed Central

Background Natural populations of most organisms, especially unicellular microorganisms, are constantly exposed to harsh environmental factors which affect their growth. UV radiation is one of the most important physical parameters which influences yeast growth in nature. Here we used 46 natural strains of Saccharomyces cerevisiae isolated from several natural populations at the “Evolution Canyon” microsite (Nahal Oren, Mt. Carmel, Israel). The opposing slopes of this canyon share the same geology, soil, and macroclimate, but they differ in microclimatic conditions. The interslope differences in solar radiation (200%–800% more on the “African” slope) caused the development of two distinct biomes. The south-facing slope is sunnier and has xeric, savannoid “African” environment while the north-facing slope is represented by temperate, “European” forested environment. Here we studied the phenotypic response of the S. cerevisiae strains to UVA and UVC radiations and to methyl methanesulfonate (MMS) in order to evaluate the interslope effect on the strains' ability to withstand DNA-damaging agents. Methodology/Principal Findings We exposed our strains to the different DNA-damaging agents and measured survival by counting colony forming units. The strains from the “African” slope were more resilient to both UVA and MMS than the strains from the “European” slope. In contrast, we found that there was almost no difference between strains (with similar ploidy) from the opposite slopes, in their sensitivity to UVC radiation. These results suggest that the “African” strains are more adapted to higher solar radiation than the “European” strains. We also found that the tetraploids strains were more tolerant to all DNA-damaging agents than their neighboring diploid strains, which suggest that high ploidy level might be a mechanism of adaptation to high solar radiation. Conclusions/Significance Our results and the results of parallel studies with several other organisms, suggest that natural selection appears to select, at a microscale, for adaptive complexes that can tolerate the higher UV radiation on the “African” slope.

Lidzbarsky, Gabriel A.; Shkolnik, Tamar; Nevo, Eviatar

2009-01-01

157

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

SciTech Connect

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.

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

2010-12-16

158

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

Microsoft Academic Search

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

Jean Chaline

2010-01-01

159

THEORETICAL INVESTIGATION OF MICROSTRUCTURE EVOLUTION AND DEFORMATION OF ZIRCONIUM UNDER CASCADE DAMAGE CONDITIONS  

SciTech Connect

This work is based on our reaction-diffusion model of radiation growth of Zr-based materials proposed recently in [1]. In [1], the equations for the strain rates in unloaded pure crystal under cascade damage conditions of, e.g., neutron or heavy-ion irradiation were derived as functions of dislocation densities, which include contributions from dislocation loops, and spatial distribution of their Burgers vectors. The model takes into account the intra-cascade clustering of self-interstitial atoms and their one-dimensional diffusion; explains the growth stages, including the break-away growth of pre-annealed samples; and accounts for some striking observations, such as of negative strain in prismatic direction, and co-existence of vacancy- and interstitial-type prismatic loops. In this report, the change of dislocation densities due to accumulation of sessile dislocation loops is taken into account explicitly to investigate the dose dependence of radiation growth. The dose dependence of climb rates of dislocations is calculated, which is important for the climb-induced glide model of radiation creep. The results of fitting the model to available experimental data and some numerical calculations of the strain behavior of Zr for different initial dislocation structures are presented and discussed. The computer code RIMD-ZR.V1 (Radiation Induced Microstructure and Deformation of Zr) developed is described and attached to this report.

Barashev, Alexander V [ORNL] [ORNL; Golubov, Stanislav I [ORNL] [ORNL; Stoller, Roger E [ORNL] [ORNL

2012-06-01

160

Real-time Monitoring Of Damage Evolution In Aerospace Materials Using Nonlinear Acoustics  

NASA Astrophysics Data System (ADS)

This work deals with the development of a novel non-destructive technique based on nonlinear acoustics, enabling real-time monitoring of material degradation in aerospace structures. When a sinusoidal ultrasonic wave of a given frequency and of sufficient amplitude is introduced into a nonlinear or an-harmonic solid, the fundamental wave distorts as it propagates, so that the second and higher harmonics of the fundamental frequency are generated. The measurement of the amplitude of these harmonics provides information on the coefficient of the second and higher order terms of the stress-strain relation for a nonlinear solid. It is demonstrated here that the material bulk nonlinear parameter for titanium alloy samples at different fatigue levels exhibits large changes compared to linear ultrasonic parameters such as velocity and attenuation. However, the use of bulk ultrasonic waves has serious disadvantages for the health monitoring of aerospace structures since it requires the placement of ultrasonic transducers on two, perfectly parallel, opposite sides of the samples. Such a setup is hardly feasible in real field conditions. For this reason, surface acoustic waves (SAW) were used in this study enabling the in-situ characterization of fatigue damage. The experimental setup for measuring the material nonlinear parameter using SAW was realised and the feasibility of the technique for health monitoring of aerospace structures was evaluated.

Matikas, T. E.; Paipetis, A.; Kostopoulos, V.

2008-06-01

161

Evolution of Ar+-damaged graphite surface during annealing as investigated by scanning probe microscopy  

NASA Astrophysics Data System (ADS)

The surface evolution of highly oriented pyrolytic graphite irradiated with Ar+ ions of 1.0 keV at doses between 5 x1011 and 1 x1013 ions/cm2 during annealing was investigated by scanning tunneling microscopy (STM) and atomic force microscopy (AFM) in the tapping mode. Hillocks were observed by both STM and AFM after ion irradiation, where the height of a hillock measured by STM was larger than that measured by AFM. The ion-irradiated surface was recovered in three stages during annealing: the first stage at 473-873 K, the second stage at 873-1473 K, and the third stage at 1473-1873 K. In the first stage, many of the ion-induced hillocks recovered rapidly and irregular domelike protrusions were formed due to both the recombination of the mobile interstitial clusters with the immobile vacancies and the aggregation of interstitial clusters. In the second stage, the hillocks recovered slightly and domelike protrusions aggregated to larger domelike protrusions. In the third stage, the hillocks recovered completely and domelike protrusions changed from irregular shapes to regular circles with monatomic step height of graphite due to the change from irregular carbon interstitial clusters to complete extraplane in graphite. Hexagonal hollows were also formed and became larger circular hollows above 1623 K with monatomic step height of graphite due to the vacancy clusters formed by the migration of vacancies and the following collapse of the neighboring layers in graphite.

An, B.; Fukuyama, S.; Yokogawa, K.; Yoshimura, M.

2002-09-01

162

Damage-induced nonassociated inelastic flow in rock salt  

SciTech Connect

The multi-mechanism deformation coupled fracture model recently developed by CHAN, et al. (1992), for describing time-dependent, pressure-sensitive inelastic flow and damage evolution in crystalline solids was evaluated against triaxial creep experiments on rock salt. Guided by experimental observations, the kinetic equation and the flow law for damage-induced inelastic flow in the model were modified to account for the development of damage and inelastic dilatation in the transient creep regime. The revised model was then utilized to obtain the creep response and damage evolution in rock salt as a function of confining pressure and stress difference. Comparison between model calculation and experiment revealed that damage-induced inelastic flow is nonassociated, dilatational, and contributes significantly to the macroscopic strain rate observed in rock salt deformed at low confining pressures. The inelastic strain rate and volumetric strain due to damage decrease with increasing confining pressures, and all are suppressed at sufficiently high confining pressures.

Chan, K.S.; Bodner, S.R. [Southwest Research Inst., San Antonio, TX (United States); Brodsky, N.S.; Fossum, A.F. [RE/SPEC, Inc., Rapid City, SD (United States); Munson, D.E. [Sandia National Labs., Albuquerque, NM (United States)

1993-06-01

163

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.

164

Computer simulation of creep damage at crack tip in short fibre composites  

Microsoft Academic Search

Creep damage at crack tip in short fibre composites has been simulated by using the finite element method (FEM). The well-known\\u000a Schapery non-linear viscoelastic constitutive relationship was used to characterize time-dependent behaviour of the material.\\u000a A modified recurrence equation was adopted to accelerate the iteration. Kachanov-Rabotnov's damage evolution law was employed.\\u000a The growth of the damage zone with time around

Zhang Shuangyin; L. W. Tsai

1994-01-01

165

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

PubMed Central

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.

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

2009-01-01

166

The effects of shockwave profile shape and shock obliquity on spallation: studies of kinetic and stress-state effects on damage evolution and spallation  

NASA Astrophysics Data System (ADS)

While much has been learned over the past five decades concerning the kinetics of the damage evolution and spallation in shock-loaded materials these studies have focused principally on 1-D shocked samples where the shocks produced possessed ``square-topped'' profiles as a function of peak stress. However, considerably less is known concerning spallation resulting from direct in-contact HE-driven, where a ``Taylor-wave'' shockwave profile is applied let alone a sweeping detonation Taylor-wave loading stress path where the applied stress tensor evolves as a function of obliquity. In this talk the influence of HE-driven shock loading, both 1-D and as a function of shock obliquity on the damage evolution and spallation response of Cu, 1018 steel, and Ta is compared and contrasted to that seen in each material subjected to flyer-plate driven ``square-topped wave'' shock profile prestraining.

Gray, George, III

2009-06-01

167

Material response to shock/dynamic loading: Windows into kinetic and stress-state effects on defect generation and damage evolution  

NASA Astrophysics Data System (ADS)

While the field of shock-wave physics has provided significant insights into many of the processes related to wave propagation in materials, the exact operative micromechanisms of defect generation occurring during the shock and thereafter those controlling defect storage and damage evolution remain incompletely understood and poorly modeled. Attainment of a truly predictive capability to enable accurate simulations of dynamic impact, shock, and high-rate loading phenomena applications requires a linked experimental, modeling, and validation research program. In this talk an overview of the microstructural mechanisms affecting the strength of materials at high pressure and strain rates as well as the processes controlling damage evolution during shock loading will be reviewed. The spectrum of physical phenomena and the potential nation-wide experimental facilities poised to study them is discussed. In addition, the limitations and caveats involved in using only velocimetry, single-pass radiography, and/or shock recovery alone to elucidate the 3-D aspects of defect generation, storage, and recovery will be examined in detail. Examples of how both ``real-time'' and post-mortem experimental approaches are needed to quantify dislocation / defect generation, shock-induced phase transitions, and damage evolution and spallation will be discussed.

Gray, George Thompson, III

2012-03-01

168

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

SciTech Connect

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.

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

2002-12-01

169

Development of a viscoelastic continuum damage model for cyclic loading  

NASA Astrophysics Data System (ADS)

A previously developed spectrum model for linear viscoelastic behavior of solids is used to describe the rate-dependent damage growth of a time dependent material under cyclic loading. Through the use of the iterative solution of a special Volterra integral equation, the cyclic strain history is described. The spectrum-based model is generalized for any strain rate and any uniaxial load history to formulate the damage function. Damage evolution in the body is described through the use of a rate-type evolution law which uses a pseudo strain to express the viscoelastic constitutive equation with damage. The resulting damage function is used to formulate a residual strength model. The methodology presented is demonstrated by comparing the peak values of the computed cyclic strain history as well as the residual strength model predictions to the experimental data of a polymer matrix composite.

Sullivan, R. W.

2008-12-01

170

Evolution of Different Dual-use Concepts in International and National Law and Its Implications on Research Ethics and Governance.  

PubMed

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

Rath, Johannes; Ischi, Monique; Perkins, Dana

2014-09-01

171

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

NASA Technical Reports Server (NTRS)

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.

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

172

Application of Phase Space Warping on Damage Tracking for Bearing Fault  

NASA Astrophysics Data System (ADS)

Nowadays, the significance of keeping equipment function properly each time is obvious. If equipment fails during its use, it may have disastrous consequences. Estimating remaining useful life (RUL) of equipment is a key to prevent such calamities, improve its reliability, provide security and reduce unnecessary maintenance and operational cost. The evolution and tracking of damage is the foundation of RUL predicting, and also is one of the most important content of mechanical fault diagnosis. Slow-time variable process of mechanical damage would lead the phase space reconstructed by fast-time variable vibrate signals warping. Search the dynamics characteristic law of damage evolution analysis in the phase space, and build the relationship between fast-time variable signals and slow-time variable damage, and then damage evolution tracking is possible. To validate the theory, simulation model of bearing damage evolution is built, the outer-race fault evolution signals is obtained, and the trend of evolution of degradation of bearing fault is described with Phase Space Warping (PSW) theory and Smooth Orthogonal Decomposition (SOD). The results proved the feasibility of the methodology of PSW in damage evolution tracking.

Fan, Bin; Hu, Niaoqing; Hu, Lei; Gu, Fengshou

2012-05-01

173

Postbuckling investigations of piezoelectric microdevices considering damage effects.  

PubMed

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

Sun, Zhigang; Wang, Xianqiao

2014-01-01

174

Postbuckling Investigations of Piezoelectric Microdevices Considering Damage Effects  

PubMed Central

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.

Sun, Zhigang; Wang, Xianqiao

2014-01-01

175

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

NASA Astrophysics Data System (ADS)

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.

Wang, Yiqiang; Zhang, Litong; Cheng, Laifei

2011-04-01

176

Water, law, science  

NASA Astrophysics Data System (ADS)

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.

Narasimhan, T. N.

2008-01-01

177

Influence of thermal damage on physical properties of a granite rock: Porosity, permeability and ultrasonic wave evolutions  

Microsoft Academic Search

In this paper, parameters for characterization of connected porosity and overall damage in the thermally-cracked rock of granite in order to assess, respectively, its transport properties and its mechanical strength are identified and quantified. Samples were heated to a range of peak temperatures up to 600°C at ambient pressure. Characterizations were made by measurement of porosity, gas permeability, velocity and

S. Chaki; M. Takarli; W. P. Agbodjan

2008-01-01

178

Modeling Fatigue Damage in Long-Fiber Thermoplastics  

SciTech Connect

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.

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

2009-10-30

179

In-Situ Monitoring of Damage Evolution in Glass Matrix Composites during Cyclic Loading using Nondestructive Techniques  

NASA Astrophysics Data System (ADS)

Infrared thermography is a powerful non-destructive testing technique which can be used for the detection of damage in advanced materials such as ceramic matrix composites. The purpose of this study is to apply a non-destructive methodology for analyzing, in real-time, the thermal effects in ceramic matrix composites caused by cyclic loading. Mechanical stresses induced by cyclic loading cause heat release in the composite due to failure of the interface, which results in increasing the material’s temperature. The heat waves, generated by the thermo-mechanical coupling, and the intrinsic energy dissipated during mechanical cyclic loading of the specimen, were detected by an infrared camera. The results were correlated with acoustic emission events that occurred during the damage accumulation process of the material.

Kordatos, E. Z.; Aggelis, D. G.; Dassios, K. G.; Matikas, T. E.

2013-10-01

180

Anisotropy of intermetallic particle cracking damage evolution in an Al-Mg-Si base wrought aluminum alloy under uniaxial compression  

Microsoft Academic Search

Particle cracking is an important damage mode in numerous engineering alloys having anisotropic microstructures. In this contribution,\\u000a cracking of anisotropic Fe-rich intermetallic particles in an extruded 6061 (T651) Al-alloy is quantitatively characterized\\u000a as a function of compressive strain for two loading directions. The Fe-rich intermetallic particles rotate when a compressive\\u000a load is applied parallel to the extrusion direction, which in

H. Agarwal; A. M. Gokhale; S. Graham; M. F. Horstemeyer

2002-01-01

181

Anisotropy of intermetallic particle cracking damage evolution in an Al-Mg-Si base wrought aluminum alloy under uniaxial compression  

Microsoft Academic Search

Particle cracking is an important damage mode in numerous engineering alloys having anisotropic microstructures. In this contribution, cracking of anisotropic Fe-rich intermetallic particles in an extruded 6061 (T651) Al-alloy is quantitatively characterized as a function of compressive strain for two loading directions. The Fe-rich intermetallic particles rotate when a compressive load is applied parallel to the extrusion direction, which in

H. Agarwal; A. M. Gokhale; S. Graham; M. F. Horstemeyer

2002-01-01

182

Evolution of National Wildlife Law.  

National Technical Information Service (NTIS)

In 1842 the United States Supreme Court declared that wildlife was held in trust for all citizens. Since that time the nature and scope of the federal government's involvement in the protection and conservation of wildlife have expanded steadily. With new...

1977-01-01

183

A Global/Local Finite Element Approach for Predicting Interlaminar and Intralaminar Damage Evolution in Composite Stiffened Panels Under Compressive Load  

NASA Astrophysics Data System (ADS)

This paper addresses the prediction of intralaminar and interlaminar damage onset and evolution in composite structures through the use of a finite element based procedure. This procedure joins methodologies whose credibility has been already assessed in literature such as the Virtual Crack Closure Technique (for delamination) and the ply discount approach (for matrix/fiber failures). In order to establish the reliability of the procedure developed, comparisons with literature experimental results on a stiffened panel with an embedded delamination are illustrated. The methodology proposed, implemented in ANSYS as post-processing routines, is combined with a finite element model of the panel, built by adopting both shell and solid elements within the frame of an embedded global/local approach to connect differently modelled substructures.

Pietropaoli, Elisa; Riccio, Aniello

2011-04-01

184

Laws of the accumulation of fatigue damage in steels St. 45 and 1Kh13 under the influence of programmed variable loads  

Microsoft Academic Search

1.The fatigue strength characteristics of steels St. 45 and 1Kh13 and the kinetics of the variation in cyclic inelastic strains of these materials were investigated; it was shown that the stabilized value of the inelastic strain per cycle is a measure of the intensity of the accumulation of fatigue damage under constant loading conditions.2.A method based on taking into account

V. T. Troshchenko

1973-01-01

185

Mechanical Response of Stitched T300 Mat/Urethane 420 IMR Composite Laminates: Property/Orientation Dependence and Damage Evolution  

SciTech Connect

This report presents experimental and analytical results of investigations on the mechanical response of stitched T300 mat/urethane 420 IMR composite laminates with three different lay-up configurations. Tensile tests and short-term creep and recovery tests were conducted on the laminate coupons at various orientations. The X-ray photographic technique was adopted to detect the internal damage due to external loading history. The tensile data of laminates with antisymmetric and symmetric lay-ups indicated that lay- up sequences of cross-ply laminates do not have much influence on their tensile properties. However, misalignments within the stitch-bonded plies disturb the symmetry of intended quasi-isotropic laminates and thereby cause the mechanical properties to exhibit a certain amount of angular dependence. Classic lamination theory was found to be able to provide a very good prediction of tensile properties for the stitched laminates within linear range. Creep and recovery response of laminate coupons is greatly dependent on loading angles and load levels. The internal damage of laminate coupons is also directly related to loading angles and load levels as well as loading history.

Deng, S.; Weitsman, Y.J.

2000-03-01

186

Damage of swift ions in crystalline calcium fluoride. Evolution of the ion explosion spike into a thermal spike  

NASA Astrophysics Data System (ADS)

The molecular dynamics simulation of the damage caused in calcium fluoride by the passage of a swift ion energetic enough to create vacant K-states in the host during passage in the [1 1 1] direction shows that the ion explosion characterised by a collective inward motion of anions, with an outward motion of cations which initially develops in close-packed <1 1 0> directions, is overcome by a chaotic process initiated by similar ionic motions in <1 1 2> directions. This ion explosion spike degenerates in <65 fs into a thermal spike some 55 Å in diameter. Annealing is a lengthy process but by 20 ps it had become plain that the thermal spike cools to give a stable, glassy structure some 46 Å across based on disordered fluoride-sharing CaF n clusters with a central filament composed of neutral fluorine molecules.

Young, D. A.

2006-11-01

187

Kepler's Laws  

Microsoft Academic Search

Johannes KEPLER published his three laws in 1609 and 1618 (table 1). Based on the very precise observations of Mars' orbit made by Tycho Brahe, and developed in the Copernican system, they describe the shape of the orbit of the planets around the Sun as an ellipse (first law), explain how the planets move around the Sun (second law) and

B. Mosser

2001-01-01

188

Radiation Laws  

NSDL National Science Digital Library

This site lists physical laws that describe radiation. Topics covered include the Plank Radiation Law, and the Wien and Stefan-Boltzmann Laws. The site also features a table summarizing the blackbody temperatures necessary to give a peak for emitted radiation in various regions of the spectrum, and three Java applets illustrating important properties of blackbody radiation.

Astronomy, Department O.; Knoxville, University O.

189

Defect interactions with stepped CeO?/SrTiO? interfaces: implications for radiation damage evolution and fast ion conduction.  

PubMed

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. PMID:24852551

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

2014-05-21

190

Environmental Laws  

NSDL National Science Digital Library

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.

Agency., United S.

191

Computer simulation of creep damage at crack tip in short fibre composites  

NASA Astrophysics Data System (ADS)

Creep damage at crack tip in short fibre composites has been simulated by using the finite element method (FEM). The well-known Schapery non-linear viscoelastic constitutive relationship was used to characterize time-dependent behaviour of the material. A modified recurrence equation was adopted to accelerate the iteration. Kachanov-Rabotnov's damage evolution law was employed. The growth of the damage zone with time around the crack tip was calculated and the results were shown with the so-called “digit photo”, which was produced by the printer.

Shuangyin, Zhang; Tsai, L. W.

1994-08-01

192

Water law  

SciTech Connect

Water law overlaps a number of legal fields beyond the narrow scope the term implies. These include environmental law, natural resources law, real property law, and tort law. This diversity can pose problems for those water resource administrators, consultants, and other professionals who need access to the latest legal decisions, but who cannot find the needed information in one single, convenient, and easily understood form. This new book is designed to present recent developments in water law on a level that can be easily understood, with a minimum of ''legalese.'' No prior knowledge of the law or legal system is necessary to understand the material, and all legal terms are explained in the text.

Goldfarb, W.

1984-01-01

193

32 CFR 537.5 - Applicable law.  

Code of Federal Regulations, 2013 CFR

...extent and nature of the tort. However, as to what law of damages is applicable, Maryland or Virginia depecage (choice of law) theory may apply. For example, if the flight originated in Indiana and the destination was Virginia, the conflict law of both...

2013-07-01

194

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

PubMed Central

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.

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

2012-01-01

195

Exact law of live nature  

NASA Astrophysics Data System (ADS)

Exact law of mortality dynamics in changing populations and environment is derived. It includes no explicit characteristics of animal- environment interactions (metabolism etc) which are a must for life; it is universal for all animals, from single cell yeast to humans, with their drastically different biology, evolutionary history, and complexity; it is rapidly (within few percent of life span) reversible. Such law is unique for live systems with their homeostatic self-adjustment to environment (cf. thermodynamics of liquids and glasses). The law which is valid for all live, and only live, systems is their specific natural law. Mortality is an instrument of natural selection and biological diversity. Its law, which is preserved in evolution of all species, is a conservation law of mortality, selection, evolution, biology. The law implies new kind of intrinsic mortality and adaptation which dominate in evolutionary unprecedented protected populations and, in contrast to species specific natural selection, proceed via universal stepwise rungs and reduce to universal cellular mechanism. The law demonstrates that intrinsic mortality and at least certain aspects of aging are disposable evolutionary byproducts, and directed genetic and/or biological changes may yield healthy and vital Methuselah lifespan. This is consistent with experiments. Universality implies that single cell yeast may provide a master key to the cellular mechanism of universal mortality, aging, selection, evolution, and its regulation in all animals. One may look for its manifestations in animal cells also, e.g., in their replicative senescence and cancer. Evolutionary origin and genetic nature of universality are suggested.

Azbel, Mark Ya.

2005-07-01

196

The evolution from sector-specific regulation towards competition law in EU telecom markets from 1997 to 2011: Different effects in practical implementation  

Microsoft Academic Search

The telecommunications markets in the European Union have gone through a period of rapid technological as well as economic change. After the market opening in the late 1990s, the approach to regulate these markets has likewise changed over time. Whereas a sectorspecific framework dominated the phase from 1998-2002, a more prominent role of competition law regulating telecommunications markets has become

Natascha Freund; Ernst-Olav Ruhle

2011-01-01

197

Water law  

SciTech Connect

The author pays particular attention to recent amendments to the Clean Water Act, Safe Drinking Water Act, and hazardous waste statutes. Concludes with a new chapter on regional land-use controls to safeguard water quality. This book is revised to explain the nature of law and the relationships among water law, science, water uses, water rights, and water resources management.

Goldfarb, W.

1988-01-01

198

Ohm's Law  

NSDL National Science Digital Library

See how the equation form of Ohm's law relates to a simple circuit. Adjust the voltage and resistance, and see the current change according to Ohm's law. The sizes of the symbols in the equation change to match the circuit diagram.

Simulations, Phet I.; Dubson, Michael; Gratny, Mindy

2004-06-01

199

Partition coefficients for REE between garnets and liquids - Implications of non-Henry's Law behaviour for models of basalt origin and evolution  

NASA Technical Reports Server (NTRS)

An experimental investigation of Ce, Sm and Tm rare earth element (REE) partition coefficients between coexisting garnets (both natural and synthetic) and hydrous liquids shows that Henry's Law may not be obeyed over a range of REE concentrations of geological relevance. Systematic differences between the three REE and the two garnet compositions may be explained in terms of the differences between REE ionic radii and those of the dodecahedral site into which they substitute, substantiating the Harrison and Wood (1980) model of altervalent substitution. Model calculations demonstrate that significant variation can occur in the rare earth contents of melts produced from a garnet lherzolite, if Henry's Law partition coefficients do not apply for the garnet phase.

Harrison, W. J.

1981-01-01

200

Political Analysis of the Trade Regime, from The Evolution of the Trade Regime: Politics, Law, and Economics of the GATT and the WTO  

Microsoft Academic Search

The Evolution of the Trade Regime offers a comprehensive political-economic history of the development of the world's multilateral trade institutions, the General Agreement on Tariffs and Trade (GATT) and its successor, the World Trade Organization (WTO). While other books confine themselves to describing contemporary GATT\\/WTO legal rules or analyzing their economic logic, this is the first to explain the logic

John H. Barton; Judith L. Goldstein; Timothy E. Josling; Richard H. Steinberg

201

Florida Law  

NSDL National Science Digital Library

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.

2011-01-01

202

Guass's Law  

NSDL National Science Digital Library

A Keynote Presentation exported as a clickable Quicktime movie. Gauss's Law is demonstrated in this presentation. Utilizing an insulated sphere enclosed in a spherical conducting shell. All equations are fully developed.

Dimauro, Mr. T.

2009-01-12

203

Lawful Inspections.  

ERIC Educational Resources Information Center

The sanitarian often spends much of his working day performing, reviewing, or supervising inspections. It is important that the sanitarian realize the legal implications of inspections and be prepared to perform them in accordance with the law. (RE)

Sikora, Vincent A.

1979-01-01

204

Ohm's Law  

NSDL National Science Digital Library

In this interactive simulation of Ohm’s law, adapted from the University of Colorado's Physics Education Technology project, adjust the voltage and resistance in a circuit, and observe how this affects the flow of current.

Foundation, Wgbh E.

2007-04-19

205

Prediction of Damage in A Randomly Oriented Short-Fiber Composite Plate Containing A Central Hole  

SciTech Connect

A micro-macro approach to matrix cracking in randomly oriented short-fiber composites is used in this paper for the damage and failure analysis of a random glass/epoxy plate containing a central hole under tensile loading. At the micro-scale, the virgin and reduced elastic properties of the composite are computed using micromechanical models and are then averaged over all possible orientations and weighted by an orientation distribution function. Next, the macroscopic response is performed by means of a continuum damage mechanics formulation in which the damage evolution law is obtained using a damage threshold function and the concepts of thermodynamic of continuous media. Damage accumulations leading to initiation and propagation of a macroscopic crack are modeled using a vanishing element technique.

Nguyen, Ba Nghiep; Khaleel, Mohammad A.; Bathe, K.-J.

2003-01-01

206

Damage in heterogeneous aluminum alloys  

Microsoft Academic Search

The role of damage on the mechanical response of a heterogeneous material was investigated through both mechanical testing and x-ray tomography. X-ray tomography was used to obtain quantitative information on the evolution of damage through processes occurring at both the local and global scale. The results indicate that heterogeneity in the spatial distribution of particles does influence the damage process.

Justin Gammage

2003-01-01

207

Damage in heterogeneous aluminum alloys  

Microsoft Academic Search

The role of damage on the mechanical response of a heterogeneous material was investigated through both mechanical testing and x-ray tomography. X-ray tomography was used to obtain quantitative information on the evolution of damage through processes occurring at both the local and global scale. The results indicate that heterogeneity in the spatial distribution of particles does influence the damage process.

Justin J. Gammage

2002-01-01

208

Heat transfer in damaged material  

NASA Astrophysics Data System (ADS)

Fully coupled thermo-mechanical analysis of civil engineering problems is studied. The mechanical analysis is based on damage mechanics which is useful for modeling of behaviour of quasi-brittle materials, especially in tension. The damage is assumed to be isotropic. The heat transfer is assumed in the form of heat conduction governed by the Fourier law and heat radiation governed by the Stefan-Boltzmann law. Fully coupled thermo-mechanical problem is formulated.

Kruis, J.

2013-10-01

209

Water resources, geography, and law  

SciTech Connect

Geographers have paid too little attention to law as a guiding element in many facets of natural resource use and landscape evolution. This book illustrates how the law interacts with natural and cultural processes related to water resources, and demonstrates the value of paying attention to legal dimensions. The chapters summarize water law in three areas of geographical interest: public use, allocation of rights, and boundary changes. Separate abstracts were prepared for two chapters selected for the Energy Data Base (EDB) and Energy Abstracts for Policy Analysis (EAPA).

Matthews, O.P.

1984-01-01

210

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

NASA Astrophysics Data System (ADS)

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.

Trinh, B. T.; Hackl, K.

2013-08-01

211

Multi-wavelength Observations of the Spatio-temporal Evolution of Solar Flares with AIA/SDO. I. Universal Scaling Laws of Space and Time Parameters  

NASA Astrophysics Data System (ADS)

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 Å) to test the wavelength dependence of scaling laws and statistical distributions. Except for the 171 and 193 Å 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 2), temporal (flare durations T), and spatio-temporal parameters (diffusion coefficient ?, spreading exponent ?, 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)vpropL -3, N(A)vpropA -2, N(V)vpropV -5/3, N(T)vpropT -2, and D 2 = 3/2, for a Euclidean dimension d = 3. Empirically, we find also a new strong correlation ?vpropL 0.94 ± 0.01 and the three-parameter scaling law Lvprop? T 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).

Aschwanden, Markus J.; Zhang, Jie; Liu, Kai

2013-09-01

212

Exact law of live nature  

NASA Astrophysics Data System (ADS)

The exact law of mortality dynamics in changing populations and environment is derived. It includes no explicit characteristics of animal-environment interactions (metabolism, etc.) which are a must for life; it is universal for all animals, from single-cell yeast to humans, with their drastically different biology, evolutionary history, and complexity; it is rapidly (within few percent of life span) reversible. Such a law is unique for live systems with their homeostatic self-adjustment to environment (cf. thermodynamics of liquids and glasses). The law which is valid for all live, and only live, systems is their specific natural law. Mortality is an instrument of natural selection and biological diversity. Its law, which is preserved in evolution of all species, is a conservation law of mortality, selection, evolution, biology. The law implies new kinds of intrinsic mortality and adaptation which dominate in evolutionary unprecedented protected populations and, in contrast to species-specific natural selection, proceed via universal stepwise rungs and reduce to universal cellular mechanism. The law demonstrates that intrinsic mortality and at least certain aspects of aging are disposable evolutionary byproducts, and directed genetic and/or biological changes may yield healthy and vital Methuselah lifespan. This is consistent with experiments. Universality implies that single-cell yeast may provide a master key to the cellular mechanism of universal mortality, aging, selection, evolution, and its regulation in all animals. One may look for its manifestations in animal cells also, e.g., in their replicative senescence and cancer. Evolutionary origin and genetic nature of universality are suggested.

Azbel?, Mark Ya.

2005-08-01

213

A fatigue damage accumulation model based on continuum damage mechanics and ductility exhaustion  

Microsoft Academic Search

Using continuum damage mechanics, a fatigue damage accumulation model related to ductility exhaustion has been developed. This model was applied to study fatigue damage evolution in a pressure vessel steel and two-level cyclic tests have been carried out to verify the damage accumulation model. The experimental results showed that a damage variable, D, based on ductility exhaustion can be used

Guangxu Cheng; Alan Plumtree

1998-01-01

214

World Law.  

ERIC Educational Resources Information Center

This consultant paper is intended to provide information useful to a goal of this curriculum development project in the war/peace field, that is to encourage students to search intelligently for alternatives to war. The most fundamental assumptions used in thinking about international law are described, including some assumptions about systemic…

Marvin, David

215

Contracting Law  

Microsoft Academic Search

Revised and updated to 2006, the fourth edition of Contracting Law continues the clear explanations of contract doctrine, engaging cases, and thought-provoking cultural and historical materials that have made this casebook a favorite of students and professors. Students and faculty appreciate the fact that no separate statutory supplement is necessary. Selected provisions from the Restatement Second of Contracts and the

Deborah Waire Post; Amy Hilsman Kastely; Nancy Ota; Sharon K. Hom

2006-01-01

216

E. C. proposes laws against acid rain  

Microsoft Academic Search

Germany is pushing the European Community (E.C.) to impose air pollution laws that are more stringent than those of member nations except for the Federal Republic of Germany and the Netherlands. Concerns over massive damage reports from acid rain and political pressures brought on by the emergence of the Green Party led the Kohl Administration to pass stricter laws, but

2009-01-01

217

3D Viscoelastic Damage Rheology Models of Strike-Slip Fault Systems and Their Associated Surface Deformation  

NASA Astrophysics Data System (ADS)

Material and geometric properties of a strike-slip fault zone control the seismicity patterns and spatial distribution of deformation. The goal of this work is to understand the coupled evolution of fault zones and associated deformation phenomena in various settings (lithospheric structure, temperature gradient and rheology). To simulate fault zone evolution, we use a thermodynamically-based continuum damage framework constrained by laboratory data of fracture and friction experiments (e.g., Lyakhovsky et al., 1997; Hamiel et al., 2004). Three dimensional simulations with the damage rheology model are used to investigate fault evolution from a single segment scale to large-scale long-term plate boundary. Our 3D model consists of a layered seismogenic crust governed by visco-elastic damage rheology, underlain by a visco-elastic upper mantle governed by power-law rheology. We compare the surface deformation patterns associated with a single fault embedded in a viscoelastic lithosphere (not governed by the damage rheology) with analytic solutions and with established numerical codes incorporating viscoelastic rheology (e.g., Savage and Prescott, 1978; Johnson and Segall, 2004). These results validate the use of our 3D code with the damage rheology for fault evolution studies constrained by geodetic data. We present initial results showing surface deformation patterns associated with the evolution of simple and complex strike slip fault systems. The initial results indicate that damage zones of strike slip faults form a flower structure with depth. The flower structure consists of broad damage in the top few kilometers of the seismogenic crust, and highly localized damage at depth. The initial results also indicate that the bulk of inelastic strain release during earthquakes is concentrated in the highly damaged cores of the main fault zones, but some portion with low spatial gradient is accommodated over a broad domain.

Finzi, Y.; Hearn, E. H.; Lyakhovsky, V.; Ben-Zion, Y.

2006-12-01

218

Interacting damage models mapped onto ising and percolation models  

SciTech Connect

The authors introduce a class of damage models on regular lattices with isotropic interactions between the broken cells of the lattice. Quasistatic fiber bundles are an example. The interactions are assumed to be weak, in the sense that the stress perturbation from a broken cell is much smaller than the mean stress in the system. The system starts intact with a surface-energy threshold required to break any cell sampled from an uncorrelated quenched-disorder distribution. The evolution of this heterogeneous system is ruled by Griffith's principle which states that a cell breaks when the release in potential (elastic) energy in the system exceeds the surface-energy barrier necessary to break the cell. By direct integration over all possible realizations of the quenched disorder, they obtain the probability distribution of each damage configuration at any level of the imposed external deformation. They demonstrate an isomorphism between the distributions so obtained and standard generalized Ising models, in which the coupling constants and effective temperature in the Ising model are functions of the nature of the quenched-disorder distribution and the extent of accumulated damage. In particular, they show that damage models with global load sharing are isomorphic to standard percolation theory, that damage models with local load sharing rule are isomorphic to the standard ising model, and draw consequences thereof for the universality class and behavior of the autocorrelation length of the breakdown transitions corresponding to these models. they also treat damage models having more general power-law interactions, and classify the breakdown process as a function of the power-law interaction exponent. Last, they also show that the probability distribution over configurations is a maximum of Shannon's entropy under some specific constraints related to the energetic balance of the fracture process, which firmly relates this type of quenched-disorder based damage model to standard statistical mechanics.

Toussaint, Renaud; Pride, Steven R.

2004-03-23

219

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

SciTech Connect

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 to the sand/cement ratio. This work shows that AE and X-ray tomography are complementary nondestructive methods to measure, characterise and locate damage sites in mortar. The effect of the sand proportion on damage and fracture behaviour is studied, in relation with the microstructure of the material.

Elaqra, H. [Groupe d'Etude de Metallurgie Physique et de Physique des Materiaux, GEMPPM UMR CNRS no. 5510, INSA-Lyon, F-69621 (France); Godin, N. [Groupe d'Etude de Metallurgie Physique et de Physique des Materiaux, GEMPPM UMR CNRS no. 5510, INSA-Lyon, F-69621 (France); Peix, G. [Controle Non Destructif par Rayonnements Ionisants (CNDRI) INSA-Lyon, F-69621 (France); R'Mili, M. [Groupe d'Etude de Metallurgie Physique et de Physique des Materiaux, GEMPPM UMR CNRS no. 5510, INSA-Lyon, F-69621 (France)]. E-mail: Mohamed.Rmili@insa-lyon.fr; Fantozzi, G. [Groupe d'Etude de Metallurgie Physique et de Physique des Materiaux, GEMPPM UMR CNRS no. 5510, INSA-Lyon, F-69621 (France)

2007-05-15

220

Ampere's Law  

NSDL National Science Digital Library

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.

VU Bioengineering RET Program, School of Engineering,

221

The laws of emotion  

Microsoft Academic Search

It is argued that emotions are lawful phe- nomena and thus can be described in terms of a set of laws of emotion. These laws result from the operation of emotion mechanisms that are accessible to intentional control to only a limited extent. The law of situational meaning, the law of concern, the law of reality, the laws of change,

Nico H. Frijda

1988-01-01

222

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

NASA Technical Reports Server (NTRS)

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.

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

1996-01-01

223

43 CFR 9239.1-3 - Measure of damages.  

Code of Federal Regulations, 2013 CFR

... 2013-10-01 false Measure of damages. 9239.1-3 Section 9239.1-3...Trespass § 9239.1-3 Measure of damages. (a) Unless State law provides...law shall prevail, the following minimum damages apply to trespass of timber and...

2013-10-01

224

Bragg's Law  

NSDL National Science Digital Library

It may be beneficial to have students perform the Wave Interference activity prior to engaging them in this activity. The following handouts are identical, with the exception that one is in Word format, while the other is in PDF format. The students should perform the exercise in a computer laboratory. Before proceeding through the questions, they should be given an opportunity to review the material on this web page. Bragg\\'s Law Activity Sheet (Acrobat (PDF) 73kB Mar2 10) Bragg\\'s Law Activity Sheet for Word (Microsoft Word 37kB Feb25 10) The following Powerpoint presentation can be used as an introduction to Bragg's Law. Bragg\\'s Law Powerpoint Presentation (PowerPoint 974kB Feb25 10) Wave Interference Activity Prior to investigating Bragg's law through this activity, it may be helpful to explore interference of sinusoidal waveforms by following the link below. Wave Interference Activity Bragg's Law Applet Java Applet created by Konstantin Lukin with supervision by Glenn A. Richard, Project Java Webmaster Original Bragg's Law Applet page on Mineral Physics Institute web server at Stony Brook University: Project Java - Bragg's Law and Diffraction: How waves reveal the atomic structure of crystals Bragg's Law refers to the simple equation: nà = 2d sinà derived by the English physicists Sir W.H. Bragg and his son Sir W.L. Bragg in 1913 to explain why the cleavage faces of crystals appear to reflect X-ray beams at certain angles of incidence (Ã, Ã). The variable d is the distance between atomic layers in a crystal, and the variable lambda is the wavelength of the incident X-ray beam (see applet); n is an integer. This observation is an example of X-ray wave interference (Roentgenstrahlinterferenzen), commonly known as X-ray diffraction (XRD), and was direct evidence for the periodic atomic structure of crystals postulated for several centuries. The Braggs were awarded the Nobel Prize in physics in 1915 for their work in determining crystal structures beginning with NaCl, ZnS and diamond. Although Bragg's law was used to explain the interference pattern of X-rays scattered by crystals, diffraction has been developed to study the structure of all states of matter with any beam, e.g., ions, electrons, neutrons, and protons, with a wavelength similar to the distance between the atomic or molecular structures of interest. How to Use this Applet The applet shows two rays incident on two atomic layers of a crystal, e.g., atoms, ions, and molecules, separated by the distance d. The layers look like rows because the layers are projected onto two dimensions and your view is parallel to the layers. The applet begins with the scattered rays in phase and interferring constructively. Bragg's Law is satisfied and diffraction is occurring. The meter indicates how well the phases of the two rays match. The small light on the meter is green when Bragg's equation is satisfied and red when it is not satisfied. The meter can be observed while the three variables in Bragg's are changed by clicking on the scroll-bar arrows and by typing the values in the boxes. The d and à variables can be changed by dragging on the arrows provided on the crystal layers and scattered beam, respectively. Bragg's Law Applet with details meter activated, but no constructive interference. Note that the peaks and troughs on the scattered beams are not aligned. Bragg's Law Applet with constructive interference and n = 2. Note that the peaks and troughs on the scattered beams are aligned. Deriving Bragg's Law by Paul Schields Bragg's Law can easily be derived by considering the conditions necessary to make the phases of the beams coincide when the incident angle equals and reflecting angle. The rays of the incident beam are always in phase and parallel up to the point at which the top beam strikes the top layer at atom z (Fig. 1). The second beam continues to the next layer where it is scattered by atom B. The second beam must travel the extra distance AB + BC if the two beams are to continue traveling adjacent and parallel. This extra distance must be an integral (n) multiple of the wavelength (Ã) for the phases of the two beams to be the same: nà = AB +BC (2). Fig. 1 Deriving Bragg's Law using the reflection geometry and applying trigonometry. The lower beam must travel the extra distance (AB + BC) to continue traveling parallel and adjacent to the top beam. Recognizing d as the hypotenuse of the right triangle Abz, we can use trigonometry to relate d and à to the distance (AB + BC). The distance AB is opposite à so, AB = d sinÃ(3). Because AB = BC eq. (2) becomes, nà = 2AB (4) Substituting eq. (3) in eq. (4) we have, nà = 2 d sinÃ, (1) and Bragg's Law has been derived. The location of the surface does not change the derivation of Bragg's Law. Experimental Diffraction Patterns The following figures show experimental x-ray diffraction patterns of cubic SiC using synchrotron radiation. Detail from previous image Players in the Discovery of X-ray Diffraction Friedrich and Knipping first observed Roentgenstrahlinterferenzen in 1912 after a hint from their research advisor, Max von Laue, at the University of Munich. Bragg's Law greatly simplified von Laue's description of X-ray interference. The Braggs used crystals in the reflection geometry to analyze the intensity and wavelengths of X-rays (spectra) generated by different materials. Their apparatus for characterizing X-ray spectra was the Bragg spectrometer. Laue knew that X-rays had wavelengths on the order of 1 Ã. After learning that Paul Ewald's optical theories had approximated the distance between atoms in a crystal by the same length, Laue postulated that X-rays would diffract, by analogy to the diffraction of light from small periodic scratches drawn on a solid surface (an optical diffraction grating). In 1918 Ewald constructed a theory, in a form similar to his optical theory, quantitatively explaining the fundamental physical interactions associated with XRD. Elements of Ewald's eloquent theory continue to be useful for many applications in physics. Kennedy Walker split cylinder apparatus in the Mineral Physics Institute High Pressure Laboratory at Stony Brook University Do We Have Diamonds? If we perform a high pressure experiment in a press, such as the Kennedy-Walker split cylinder apparatus, to convert graphite into diamonds, we can use X-ray diffraction techniques to determine whether we achieved the intended result. The carbon atoms in graphite are arranged into planes that are separated by d-spacings of 3.35Ã. If we use X-rays with a wavelength (Ã) of 1.54Ã, and we have diamonds in the material we are testing, we will find peaks on our X-ray pattern at à values that correspond to each of the d-spacings that characterize diamond. These d-spacings are 1.075Ã, 1.261Ã, and 2.06Ã. To discover where to expect peaks if diamond, graphite, or both are present, you can set à to 1.54à in the applet, and set distance to one of the d-spacings. Then start with à at 6 degrees, and vary it until you find a Bragg's condition. Do the same with each of the remaining d-spacings. Remember that in the applet, you are varying Ã, while on the X-ray pattern printout, the angles are given as 2Ã. Consequently, when the applet indicates a Bragg's condition at a particular angle, you must multiply that angle by 2 to locate the angle on the X-ray pattern printout where you would expect a peak. First stage anvils in the Kennedy Walker split cylinder apparatus

Richard, Glenn

225

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)

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.

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

1998-01-01

226

A Relationship between Lotka's Law, Bradford's Law, and Zipf's Law.  

ERIC Educational Resources Information Center

A common functional relationship among Lotka's law, Bradford's law, and Zipf's law is derived. The proof takes explicit account of the sequences of observed values of the variables by means of an index. This approach results in a more realistic and precise formulation of each law. (Author/EM)

Chen, Ye-Sho; Leimkuhler, Ferdinand F.

1986-01-01

227

32 CFR 750.33 - Damages.  

Code of Federal Regulations, 2013 CFR

... 2013-07-01 2013-07-01 false Damages. 750.33 Section 750.33 National...REGULATIONS Federal Tort Claims Act § 750.33 Damages. (a) Generally. The measure of damages is determined by the law of the...

2013-07-01

228

EFFECT OF CREVICE FORMER ON CORROSION DAMAGE PROPAGATION  

SciTech Connect

The objectives of this report are: (1) To determine the effect of the crevice former on the localized corrosion damage propagation; (2) FOCUS on post initiation stage, crevice propagation and arrest processes; (3) Determine the evolution of damage--severity, shape, location/distribution, damage profile; and (4) Model of crevice corrosion propagation, i.e. the evolution of the crevice corrosion damage profile.

J.H. Payer; U. Landau; X. Shan; A.S. Agarwal

2006-03-01

229

Undermining Evolution: Where State Standards Go Wrong  

ERIC Educational Resources Information Center

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…

American Educator, 2012

2012-01-01

230

Effects of multiaxial stress state and saltwater on fatigue damage and failure of glass/epoxy composite  

NASA Astrophysics Data System (ADS)

Fiber composites used in advanced mechanical systems are generally subjected to cyclic loading with multiaxial stress state. Thus multiaxial fatigue is a subject of major importance in design and evaluation of long-term performance of composite structures and components. Theoretical work was initially performed to address the fundamental issues of damage evolution and material degradation in glass/epoxy composites subject to multiaxial cyclic stresses. A continuum damage mechanics formulation based on irreversible thermodynamics was used to construct multiaxial cyclic constitutive equations of the composite. With coupling of damage anisotropy and multiaxial stress state and using Gibb's free energy function, damage driving force was determined. Based on the second principle of thermodynamics, evolution equations were also obtained to describe the change of the damage state in the composite under multiaxial fatigue loading. A newly introduced failure-life theory was employed for the fiber composite, based on anisotropic nature of composite strength property and distinct mechanisms of microcrack formation and growth under different multiaxial cyclic stresses. A driving force for fatigue failure was formulated with a governing function, involving combined cyclic shear and transverse tensile stresses along the weakest principal material plane of the composite. Multiaxial fatigue life of the composite was related to the forcing function using a power-law. A formulation of thermomechanical response of a fiber composite based on the general thermodynamics theory was proposed to establish a model that can couple water sorption, applied stress and damage in the composite. Starting from general Gibbs free energy, constitutive equations, which describe the relationships between state variables and corresponding driving forces, were derived. The evolution laws that describe relationships of damage driving force-damage evolution and chemical potential gradient-water flux were also given. Critical multiaxial fatigue experiments were conducted on filament-wound glass/epoxy composite tubular specimens to characterize the damage initiation and evolution. At the same time, experiment data were also been used to determine the material and multiaxial stress parameters of the fatigue-life laws for the composite and to demonstrate the validity of the theory.

Wang, Feng

231

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. ...

232

Ductile damage at large plastic strains: Models, numerical issues and transition to fracture  

NASA Astrophysics Data System (ADS)

The introduction of new effects, both in the plastic flow rule of the material and in the evolution laws for internal variables like damage, namely the importance of taking into account triaxiality and the influence of the third invariant of the deviatoric stress tensor in the modeling of mechanical behavior of metallic materials is here assessed. To solve mesh dependency associated with numerical implementation of strain softening laws a non-local approach of integral-type is used. A comprehensive assessment of several non-local models is carried out for different values of stress triaxiality and third invariant of the deviatoric stress tensor. A continuous-discontinuos model, based on the XFEM, in order to handle simultaneously large strains, damage localisation and crack propagation is discussed.

Cesar de Sa, J. M. A.

2013-12-01

233

On Common Ground: Jost's (1897) Law of Forgetting and Ribot's (1881) Law of Retrograde Amnesia  

ERIC Educational Resources Information Center

T. Ribot's (1881) law of retrograde amnesia states that brain damage impairs recently formed memories to a greater extent than older memories, which is generally taken to imply that memories need time to consolidate. A. Jost's (1897) law of forgetting states that if 2 memories are of the same strength but different ages, the older will decay more…

Wixted, John T.

2004-01-01

234

Elastic moduli evolution and accompanying stress changes with increasing crack damage: implications for stress changes around fault zones and volcanoes during deformation  

Microsoft Academic Search

The elastic moduli of rock in areas susceptible to crack damage, such as within fault zones or volcanic edifices, can be subject to large modifications. Knowledge of how elastic moduli may vary in such situations is important for both the reliable modelling of volcano deformation and stability and for linear and non-linear elastic crack models for earthquake rupture. Furthermore, it

M. J. Heap; D. R. Faulkner; P. G. Meredith; S. Vinciguerra

2010-01-01

235

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.

236

Entropic Corrections to Coulomb's Law  

NASA Astrophysics Data System (ADS)

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 ?. Our study further supports the unification of gravity and electromagnetic interactions based on the holographic principle.

Hendi, S. H.; Sheykhi, A.

2012-04-01

237

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

NASA Astrophysics Data System (ADS)

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).

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

2010-12-01

238

Evolution of damage in the lens after in vivo close to threshold exposure to UV-B radiation: cytomorphological study of apoptosis.  

PubMed

The purpose of the present study was to investigate cataractogenesis and recovery of lens damage after in vivo close to threshold ultraviolet (UV)-B radiation around 300 nm. Eighty six-week-old albino Sprague-Dawley rats were familiarized to a rat restrainer five days prior to exposure. Groups of non-anesthetized rats were exposed unilaterally to 8 kJ/m(2) UVR-300 nm. The animals were sacrificed at 1, 7, 48 and 336h following exposure. The lenses were extracted for imaging of dark-field lens macro anatomy and measurement of intensity of forward lens light scattering to quantify lens opacities. Three exposed lenses and one non-exposed lens from each time interval were examined with light and transmission electron microscopy (TEM). Macro anatomy and lens light scattering revealed that all contralateral non-exposed lenses were clear. The degree of lens opacity (difference in lens light scattering between exposed and non-exposed lenses) increased during the 336h, reaching a plateau towards the end of the observation period. Light microscopy and TEM demonstrated that apoptotic features appeared in the epithelium already 1h after UVR exposure, and small vacuoles were seen in the outer cortex. Epithelial damage occurs during the first 48h after exposure and is followed by regenerative repair at 336h post-exposure. Apoptotic epithelial cells were phagocytized by adjacent epithelial cells. Cortical fiber cells exhibited increasing damage throughout the observation period without any clear repair after 336h. In conclusion, acute UVR-induced cataract is partly a reversible. Lens epithelium is a primary target for UVR exposure. Damage to cortical fiber cells remained irreversible. PMID:20599969

Galichanin, Konstantin; Löfgren, Stefan; Bergmanson, Jan; Söderberg, Per

2010-09-01

239

Acid mine drainage: Common law, SMCRA, and the Clean Water Act  

Microsoft Academic Search

Acid mine drainage is a major problem related to coal mining which, if unabated, can severely damage the aquatic environment. Damage resulting from acid mine drainage was first addressed by common law and riparian principles. As societal laws changed, common law principles alone could not effectively control this problem. Preventing and controlling pollution including acid mine drainage are important goals

Henrich

1995-01-01

240

Finite element analysis on creep damage  

Microsoft Academic Search

An implicit, iterative semi-analytical integration scheme is proposed to integrate the Leckie-Hayhurst isotropic creep damage evolution equation as well as the Bailey-Norton creep constitutive equation. This scheme is incorporated to a finite element programme dealing with thermal elastic plastic creep problems. Creep damage evolution and rupture time in a high temperature structure can be predicted.

X. N. Wang; X. C. Wang

1996-01-01

241

The Role of Elastic and Plastic Anisotropy of Sn in Recrystallization and Damage Evolution During Thermal Cycling in SAC305 Solder Joints  

SciTech Connect

Because failures in lead-free solder joints occur at locations other than the most highly shear-strained regions, reliability prediction is challenging. To gain physical understanding of this phenomenon, physically based understanding of how elastic and plastic deformation anisotropy affect microstructural evolution during thermomechanical cycling is necessary. Upon solidification, SAC305 (Sn-3.0Ag-0.5Cu) solder joints are usually single or tricrystals. The evolution of microstructures and properties is characterized statistically using optical and orientation imaging microscopy. In situ synchrotron x-ray measurements during thermal cycling are used to examine how crystal orientation and thermal cycling history change strain history. Extensive characterization of a low-stress plastic ball grid array (PBGA) package design at different stages of cycling history is compared with preliminary experiments using higher-stress package designs. With time and thermal history, microstructural evolution occurs mostly from continuous recrystallization and particle coarsening that is unique to each joint, because of the specific interaction between local thermal and displacement boundary conditions and the strong anisotropic elastic, plastic, expansion, and diffusional properties of Sn crystals. The rate of development of recrystallized microstructures is a strong function of strain and aging. Cracks form at recrystallized (random) boundaries, and then percolate through recrystallized regions. Complications arising from electromigration and corrosion are also considered.

Bieler, Thomas R.; Zhou, Bite; Blair, Lauren; Zamiri, Amir; Darbandi, Payam; Pourboghrat, Farhang; Lee, Tae-Kyu; Liu, Kuo-Chuan (Michigan); (Cisco)

2013-04-08

242

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)

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.

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

2014-01-01

243

Demonstrating the Gas Laws.  

ERIC Educational Resources Information Center

Presents a complete computer program demonstrating the relationship between volume/pressure for Boyle's Law, volume/temperature for Charles' Law, and volume/moles of gas for Avagadro's Law. The programing reinforces students' application of gas laws and equates a simulated moving piston to theoretical values derived using the ideal gas law.…

Holko, David A.

1982-01-01

244

AALS Law Books Recommended  

Microsoft Academic Search

The years following World War I1 witnessed the creation of many new law schools. Standards were needed for all aspects of both law school and law library administration. The AALS, under the presidency of Professor Walter Gellhorn, sponsored the creation of a major list of titles recommended for acquisitions by academic law libraries. The list, Law Boob Recommended for Libraries,

Mark P. Bernstein

1989-01-01

245

law, economic analysis of  

Microsoft Academic Search

This article surveys the economic analysis of five primary fields of law: property law; liability for accidents; contract law; litigation; and public enforcement and criminal law. It also briefly considers some criticisms of the economic analysis of law. Keywords adverse possession; asymmetric information; Becker, G.; Bentham, J.; bona fide purchase rule; Coase, R.; collective action; compensated takings; contract formation; contractual

A. Mitchell Polinsky; Steven Shavell

246

Tornado Damage!  

NSDL National Science Digital Library

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.

Integrated Teaching And Learning Program

247

Characterization of creep and creep damage by in-situ microtomography  

NASA Astrophysics Data System (ADS)

Application of in-situ microtomography to characterization of power law creep and creep damage in structural materials is presented. It is shown first that the successively reconstructed volumes are adequately monitoring the macroscopic sample shape and that microtomography is an optimal tool to characterize inhomogeneous specimen deformation. Based on a two-step image correlation technique the evolution of single voids is revealed and the basis of a pioneering approach to creep damage studies is presented. The method allows the unequivocal separation of three concurrent damage mechanisms: nucleation, growth, and coalescence of voids. The results indicate that growth rate of voids with equivalent diameters in the range of 2-5 mm is of about one order of magnitude higher than the prediction of continuum solid mechanics. Analysis of void coalescence points out the presence of two stable growth regimes related to coalescence between primary and secondary voids, respectively.

Borbély, András; Dzieciol, Krzysztof; Sket, Federico; Isaac, Augusta; di Michiel, Marco; Buslaps, Thomas; Kaysser-Pyzalla, Anke R.

2011-07-01

248

Primary Radiation Damage Formation  

SciTech Connect

The physical processes that give rise to changes in the microstructure, and the physical and mechanical properties of materials exposed to energetic particles are initiated by essentially elastic collisions between atoms in what has been called an atomic displacement cascade. The formation and evolution of this primary radiation damage mechanism are described to provide an overview of how stable defects are formed by displacement cascades, as well as the nature and morphology of the defects themselves. The impact of the primary variables cascade energy and irradiation temperature are discussed, along with a range of secondary factors that can influence damage formation.

Stoller, Roger E [ORNL

2012-01-01

249

Full-scale prestress loss monitoring of damaged RC structures using distributed optical fiber sensing technology.  

PubMed

For the safety of prestressed structures, prestress loss is a critical issue that will increase with structural damage, so it is necessary to investigate prestress loss of prestressed structures under different damage scenarios. Unfortunately, to date, no qualified techniques are available due to difficulty for sensors to survive in harsh construction environments of long service life and large span. In this paper, a novel smart steel strand based on the Brillouin optical time domain analysis (BOTDA) sensing technique was designed and manufactured, and then series of tests were used to characterize properties of the smart steel strands. Based on prestress loss principle analysis of damaged structures, laboratory tests of two similar beams with different damages were used to verify the concept of full-scale prestress loss monitoring of damaged reinforced concrete (RC) beams by using the smart steel strands. The prestress losses obtained from the Brillouin sensors are compared with that from conventional sensors, which provided the evolution law of prestress losses of damaged RC beams. The monitoring results from the proposed smart strand can reveal both spatial distribution and time history of prestress losses of damaged RC beams. PMID:22778590

Lan, Chunguang; Zhou, Zhi; Ou, Jinping

2012-01-01

250

Full-Scale Prestress Loss Monitoring of Damaged RC Structures Using Distributed Optical Fiber Sensing Technology  

PubMed Central

For the safety of prestressed structures, prestress loss is a critical issue that will increase with structural damage, so it is necessary to investigate prestress loss of prestressed structures under different damage scenarios. Unfortunately, to date, no qualified techniques are available due to difficulty for sensors to survive in harsh construction environments of long service life and large span. In this paper, a novel smart steel strand based on the Brillouin optical time domain analysis (BOTDA) sensing technique was designed and manufactured, and then series of tests were used to characterize properties of the smart steel strands. Based on prestress loss principle analysis of damaged structures, laboratory tests of two similar beams with different damages were used to verify the concept of full-scale prestress loss monitoring of damaged reinforced concrete (RC) beams by using the smart steel strands. The prestress losses obtained from the Brillouin sensors are compared with that from conventional sensors, which provided the evolution law of prestress losses of damaged RC beams. The monitoring results from the proposed smart strand can reveal both spatial distribution and time history of prestress losses of damaged RC beams.

Lan, Chunguang; Zhou, Zhi; Ou, Jinping

2012-01-01

251

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

NASA Astrophysics Data System (ADS)

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.

Hayakawa, Kunio; Nakamura, Tamotsu; Tanaka, Shigekazu

2007-05-01

252

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

SciTech Connect

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.

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

2007-05-17

253

Transitions in midwestern ground water law  

Microsoft Academic Search

The evolution of ground-water law in eight states in the Midwest (Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, Ohio, and Wisconsin) is examined, and a review of transitions in ground-water doctrines is presented. Two underlying themes in changing ground-water management are communicated. First, ground-water law is evolving from private property rules of capture based on the absolute ownership doctrines to rules

Jean A. Bowman; Gary R. Clark

1989-01-01

254

Scaling laws and indications of self-organized criticality in urban systems  

Microsoft Academic Search

Evolution of urban systems has been considered to exhibit some form of self-organized criticality (SOC) in the literature. This paper provides further mathematical foundations and empirical evidences to support the supposition. The hierarchical structure of systems of cities can be formulated as three exponential functions: the number law, the population size law, and the area law. These laws are identical

Yanguang Chen; Yixing Zhou

2008-01-01

255

Towards Coherent Regulation of Law Enforcement Surveillance in the Network Society  

Microsoft Academic Search

In this paper, we study the evolution of telecommunications technology and its impact on law enforcement surveillance. Privacy and the need for law enforcement to conduct investigations have not been at the center of the recent public policy debate. Yet, policy environments have approved law enforcement surveillance that can be and is intrusive. Law enforcement surveillance therefore deserves particular attention

Serena Chan; L. Jean Camp

256

A Grained Continuum Theory of Damage and Coarsening  

NASA Astrophysics Data System (ADS)

Formation of tectonic plate boundaries from mantle and lithosphere dynamics involves shear localization during deformation as well as remnant weak zones after deformation ceases. The requisite state variable that delineates the weak zone could be, for example, increased temperature or water content, although a well documented feature of lithospheric weak zones is reduced grainsize (i.e., mylonites). Grainsize reduction is typically attributed to dynamic recrystallization although the models arising from this hypothesis are problematic: grainsize reduction occurs during dislocation creep while the rheological effect of grainsize occurs in diffusion creep and these creep mechanisms exist in different stress regimes. Moreover, the grain-growth ("healing") laws employed for these models assume static grain-growth or coarsening, although the setting itself is far from static or equilibrium. Here we present a new grained-continuum theory for simultaneous and competing coarsening and grainsize reduction through a "damage" mechanics and nonequilibrium thermodynamics approach. The theory contains coupled grainsize/statistical and continuum/macroscopic components. The grainsize/statistical element of the theory prescribes the evolution of the grainsize distribution through space and time, and a kinetic phenomenological (i.e., nonequilibrium thermodynamic) law for how grainzize changes depending on free energy differences between grains, including both grain-boundary surface energy (which controls coarsening) and the contribution of deformational work to these free energies (which controls damage). The continuum level of the theory considers standard mass, momentum and energy conservation on the statistically averaged grained continuum; however, the continuum treatment of energy conservation and entropy-source positivity provide the phenomenological law for the statistical grain-growth law. A fundamental thermodynamic requirement arising from the theory is that deformational work must always cause large grains to shrink and small ones to grow, causing the grainsize distribution to propagate to smaller grainsizes and thus to mean grainsize reduction. The theory also captures the essential static-coarsening predictions of self-similar grainsize distributions from Lifshitz-Slyosov and Hillert theories. However, with the inclusion of nonstatic/nonequilibrium conditions such as damage and deformational work, the theory also predicts a range of self-similar and non-self-similar (even singular) grainsize distribution evolutions involving either coarsening or grainsize reduction and shear localization.

Bercovici, D.; Ricard, Y.

2005-12-01

257

THERMODYNAMICAL ASPECTS OF IMPLICIT GRADIENT DAMAGE  

Microsoft Academic Search

A gradient damage formulation for quasi-brittle damage is derived from a nonstandard expression for the free energy potential. In contrast with many existing approaches, the nonstandard terms are related to the kinematics of the problem and therefore come into play already in the elastic regime. Following the argument that the second law of thermodynamics need only be satisfied globally for

R. H. J. PEERLINGS; M. G. D. GEERS

258

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

259

Students and the Law.  

ERIC Educational Resources Information Center

Designed as a practical approach to the study of law, this publication offers seven lesson plans focusing on legal topics that have potential significance to high school students preparing to enter the world of work. Lesson plans address the following topics: minors and the law, automobile insurance, employment law, sports and the law, computer…

South Carolina State Dept. of Education, Columbia. Office of Vocational Education.

260

Innovations in Law.  

ERIC Educational Resources Information Center

This issue of "Bill of Rights in Action" looks at historical and recent innovations in law. The first article examines the code of laws developed by the ancient Hebrews which influenced Roman law, English law, and the U.S. Declaration of Independence and Constitution. The second article explores Thomas Jefferson's writing of the Declaration of…

Martz, Carlton

2000-01-01

261

[Teaching about Family Law].  

ERIC Educational Resources Information Center

This issue of "Focus on Law Studies""contains a special emphasis on teaching about law and the family", in the form of the following three articles: "Teaching Family Law: Growing Pains and All" (Susan Frelich Appleton); "The Family Goes to Court: Including Law in a Sociological Perspective on the Family" (Mary Ann Lamanna); and Michael Grossberg's…

Ryan, John Paul, Ed.

1992-01-01

262

Hyperphysics: Kepler's Laws  

NSDL National Science Digital Library

This Hyperphysics page, from Georgia State University, provides detailed explanations for each of Kepler's Laws: the Law of Orbits, Law of Periods, and the Law of Areas. Each description offers appropriate formulas and equations as well as related images and graphics. Various links are provided throughout the article for related information.

Nave, Carl R.

2008-10-28

263

Enforceable social laws  

Microsoft Academic Search

In this paper we study the enforcement of social laws in artificial social systems using a control system. We define the enforceable social law problem as an extension of Tennenholtz' stable social law problem. We distinguish the choice of social laws from the choice of control systems, where the latter leads to new computational problems. We consider also properties of

Guido Boella; Leendert W. N. van der Torre

2005-01-01

264

Toxic torts and environmental law: Recent developments  

SciTech Connect

This article describes recent developments in environmental law including the following: in Toxic tort issues: standards for expert testimony; punitive damages; preemption; failure to warn and strict liability; the unavoidably unsafe defense; in Hazardous waste issues: joint and several liability; petroleum exclusion; recoverable costs; causation; owner or operator and successor liability; contribution; commerce; RCRA land bar; criminal conviction.

Mahoney, W.F. [ed.; Murphy, J.; Cross, A. [Segal, McCambridge, Singer & Mahoney, Ltd., Chicago, IL (United States)] [and others

1994-12-31

265

A methodology to predict creep life for advanced ceramics using continuum damage mechanics  

SciTech Connect

A methodology is proposed to estimate creep rupture life for advanced ceramics such as continuous fiber reinforced ceramic matrix composites (CFCMC). Based on the premise that the damage pattern takes the form of a heterogeneous distribution of grain boundary cavities in the majority of creep life, a damage parameter is incorporated in various creep strain rate equations. The resulting constitutive equations for creep strain and accumulated damage are cast in terms of stress, and other affinities. It is pointed out that these affinities can be derived from a scalar creep potential in non equilibrium thermodynamics. The evolutionary laws are formulated based on many micro-mechanical models. The time-dependent reliability or hazard rate for a SiC is then established by damage mechanics with Weibull analysis. A unit cell model is presented for predicting life of a uni-directional CFCMC subjected to a constant far-field stress. A system of coupled flrst order ordinary differential equations is derived from which the evolution of creep damage can be solved giving the rupture life. It is shown that the stress dependence on the lifetime is very sensitive to the type of damage mechanisms active at the microstructural level.

Chuang, T.J.; Duffy, S.F.

1994-01-01

266

Subsidence: an emerging area of the law  

SciTech Connect

This Note surveys various legal theories courts could employ to compensate property owners injured by subsidence caused by groundwater pumping. Many courts have clouded the subsidence issue by applying water law to determine liability. Dissatisfied with the results of applying water law to subsidence, the Texas Supreme Court held, in the landmark Friendswood decision, that negligence would be a cause of action to redress future subsidence. The best theory of liability for subsidence damage, however, is loss of subjacent support. The prevailing rule under the law of support is that the defendant is strictly liable for damage resulting from withdrawal of support. The Restatement and several cases have finally recognized that there is no valid distinction between withdrawal of solid and fluid substances for purposes of imposing strict liability under subjacent support principles. Since subsidence may result from groundwater pumping even in the absence of negligence, strict liability is superior to a negligence theory. Unlike any water law theory, the law of support recognizes that the injury is to rights in land rather than to water rights. Until legislatures respond to the problem, adherence to the law of subjacent support is the best approach to internalizing the costs of subsidence.

Morris, J.

1981-01-01

267

Effect of Crevice Former on Corrosion Damage Propagation.  

National Technical Information Service (NTIS)

The objectives of this report are: (1) To determine the effect of the crevice former on the localized corrosion damage propagation; (2) FOCUS on post initiation stage, crevice propagation and arrest processes; (3) Determine the evolution of damage--severi...

2006-01-01

268

Identifying Multidimensional Damage in a Hierarchical Dynamical System  

Microsoft Academic Search

In this paper, we present a novel method for multidimensional damage identification based on a dynamical systems approach to damage evolution. This approach does not depend on the knowledge of particular damage physics, and is appropriate for systems where damage evolves on much slower time scale than the directly observable dynamics. In an experimental context, the phase space reconstruction and

David Chelidze

2004-01-01

269

Water Law in Spain After 1985  

Microsoft Academic Search

Spain has old and complex legislation with regard to water. The current state of evolution in water law is one of vagueness, with contrasting lines of tension: in some areas, the old focus predominates but there are others in which the so-called new water culture can be detected. There are two legal references to mention and comment on: first, the

Antonio Embid Irujo

2003-01-01

270

A universal wear law for abrasion  

Microsoft Academic Search

Finding a wear law that is valid over a wide range of conditions and materials would have enormous practical value. The authors have previously discovered a simple relationship describing the evolution of the abrasive wear rate of steel sliding against boron carbide-coated coupons, and have developed a model accounting for its kinetics. The authors show here that this wear equation

Matthew T. Siniawski; Stephen J. Harris; Qian Wang

2007-01-01

271

Evolution and Friendship  

ERIC Educational Resources Information Center

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.…

Mena-Werth, Jose

2005-01-01

272

Right Hemisphere Brain Damage  

MedlinePLUS

Right Hemisphere Brain Damage [ en Español ] What is right hemisphere brain damage ? What are some signs or symptoms of right hemisphere ... right hemisphere brain damage ? What is right hemisphere brain damage? Right hemisphere brain damage is damage to ...

273

Life as a manifestation of the second law of thermodynamics  

Microsoft Academic Search

We examine the thermodynamic evolution of various evolving systems, from primitivephysical systems to complex living systems, and conclude that they involve similar processeswhich are phenomenological manifestations of the second law of thermodynamics. We take thereformulated second law of thermodynamics of Hatsopoulos and Keenan and Kestin and extendit to nonequilibrium regions, where nonequilibrium is described in terms of gradientsmaintaining systems at

Eric D. Schneider; James J. Kay

1994-01-01

274

32 CFR 750.69 - Measure of damages.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Measure of damages. 750.69 Section 750.69 National...Provision of Law § 750.69 Measure of damages. Generally, the measure-of-damage provisions under the MCA are used to...

2013-07-01

275

State Workers' Compensation Laws.  

National Technical Information Service (NTIS)

The report is comprised of tables of benefits, on a state by state basis, as required by law including: Type of Law and Insurance Requirements for Private Employment; Numerical Exemptions; Coverage of Agricultural Workers; Jurisdictions in Which Workers' ...

1992-01-01

276

State Workers' Compensation Laws.  

National Technical Information Service (NTIS)

The document contents include: Type of law and insurance requirements for private employment; Numerical exemptions; Coverage of agricultural workers; Jurisdictions in which workers' compensation laws apply to domestic employment; Medical benefits and meth...

1989-01-01

277

State Workers' Compensation Laws.  

National Technical Information Service (NTIS)

Table of Contents: Type of Law and Insurance Requirements for Private Employment; Numerical Exemptions; Coverage of Agricultural Workers; Jurisdictions in Which Workers' Compensation Laws Aply to Domestic Employment; Medical Benefits and Methods of Physic...

1990-01-01

278

Generalized law for aftershocks  

NSDL National Science Digital Library

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.

Shcherbakov, Robert; Rundle, John B.; Turcotte, Donald L.; Agu

279

Alabama Marine Law Program.  

National Technical Information Service (NTIS)

The Alabama Marine Law Program at the University of Alabama Law Center was funded from January 1, 1979 to May 31, 1982. During this period, the Program had as its continuing objective research, service and education in issues relating to law and the coast...

1982-01-01

280

Communication, Law, and Justice.  

ERIC Educational Resources Information Center

The author takes the position that communication is an essential, but often overlooked component of law and justice; furthermore, some of the current problems in the area of law and justice are basically communication problems. The author traces the early development of communication and law as closely related disciplines, with emphasis on the…

Anapol, Malthon M.

281

Kepler and his Laws  

NSDL National Science Digital Library

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.

Stern, David

282

Laws of Thermodynamics  

NSDL National Science Digital Library

This lesson explains the two laws of thermodynamics that govern the relationship between energy and natural systems. These are the Law of Conservation of Energy and Law of Entropy. Key terms are hyperlinked so that students can easily find definitions to unfamiliar words.

2012-06-11

283

Hyperbolic evolution system for numerical relativity  

SciTech Connect

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.

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

1992-02-24

284

Approximation of Laws  

NASA Astrophysics Data System (ADS)

Approximation of laws is an important theme in the philosophy of science. If we can make sense of the idea that two scientific laws are "close" to each other, then we can also analyze such methodological notions as approximate explanation of laws, approximate reduction of theories, approximate empirical success of theories, and approximate truth of laws. Proposals for measuring the distance between quantitative scientific laws were given in Niiniluoto (1982, 1987). In this paper, these definitions are reconsidered as a response to the interesting critical remarks by Liu (1999).

Niiniluoto, Ilkka

2014-03-01

285

Is life law-like?  

PubMed

Genes are generally assumed to be primary biological causes of biological phenotypes and their evolution. In just over a century, a research agenda that has built on Mendel's experiments and on Darwin's theory of natural selection as a law of nature has had unprecedented scientific success in isolating and characterizing many aspects of genetic causation. We revel in these successes, and yet the story is not quite so simple. The complex cooperative nature of genetic architecture and its evolution include teasingly tractable components, but much remains elusive. The proliferation of data generated in our "omics" age raises the question of whether we even have (or need) a unified theory or "law" of life, or even clear standards of inference by which to answer the question. If not, this not only has implications for the widely promulgated belief that we will soon be able to predict phenotypes like disease risk from genes, but also speaks to the limitations in the underlying science itself. Much of life seems to be characterized by ad hoc, ephemeral, contextual probabilism without proper underlying distributions. To the extent that this is true, causal effects are not asymptotically predictable, and new ways of understanding life may be required. PMID:21828277

Weiss, Kenneth M; Buchanan, Anne V

2011-08-01

286

Is Life Law-Like?  

PubMed Central

Genes are generally assumed to be primary biological causes of biological phenotypes and their evolution. In just over a century, a research agenda that has built on Mendel’s experiments and on Darwin’s theory of natural selection as a law of nature has had unprecedented scientific success in isolating and characterizing many aspects of genetic causation. We revel in these successes, and yet the story is not quite so simple. The complex cooperative nature of genetic architecture and its evolution include teasingly tractable components, but much remains elusive. The proliferation of data generated in our “omics” age raises the question of whether we even have (or need) a unified theory or “law” of life, or even clear standards of inference by which to answer the question. If not, this not only has implications for the widely promulgated belief that we will soon be able to predict phenotypes like disease risk from genes, but also speaks to the limitations in the underlying science itself. Much of life seems to be characterized by ad hoc, ephemeral, contextual probabilism without proper underlying distributions. To the extent that this is true, causal effects are not asymptotically predictable, and new ways of understanding life may be required.

Weiss, Kenneth M.; Buchanan, Anne V.

2011-01-01

287

CONSTITUTIVE RELATIONSHIP OF TISSUE BEHAVIOR WITH DAMAGE ACCUMULATION OF HUMAN CORTICAL BONE  

PubMed Central

Microdamage accumulation has been identified as a major conduit for bone tissues to absorb fracture energy. Due to the poor understanding of its underlying mechanism, however, an adequate constitutive relationship between damage accumulation and the mechanical behavior of bone has not yet been established. In this study, the constitutive relationship between the damage accumulation induced by overload and the evolution of mechanical properties of bone with incremental deformation was established based on the experimental results obtained from a novel progressive loading protocol developed in our laboratory. First, a decayed exponential model was proposed to capture the damage accumulation (modulus loss) with increasing applied strain. Next, a power law function was proposed to represent the progression of plastic deformation with damage accumulation. Finally, a linear combination of the Kohlrausch-Williams-Watts (KWW) function and Debye function was used to depict the viscoelastic behavior of bone associated with damage accumulation. The results of this study may help develop a constitutive model for predicting the mechanical behavior of cortical bone tissues.

Luo, Qing; Leng, Huijie; Acuna, Rae; Dong, Xuanliang; Rong, Qiguo; Wang, Xiaodu

2010-01-01

288

Effects of Burn Rate on the Spatial Extent of Fracture Damage in an Underground Explosion (Postprint).  

National Technical Information Service (NTIS)

The quasistatic micromechanical damage mechanics originally formulated by Ashby and Sammis has been made fully dynamical by the incorporation of physically motivated crack growth laws. This rate-dependent damage mechanics has been implemented in the ABAQU...

C. G. Sammis

2012-01-01

289

Gas evolution from spheres  

SciTech Connect

Gas evolution from spherical solids or liquids where no convective processes are active is analyzed. Three problem classes are considered: (1) constant concentration boundary, (2) Henry's law (first order) boundary, and (3) Sieverts' law (second order) boundary. General expressions are derived for dimensionless times and transport parameters appropriate to each of the classes considered. However, in the second order case, the non-linearities of the problem require the presence of explicit dimensional variables in the solution. Sample problems are solved to illustrate the method. 5 refs., 4 figs.

Longhurst, G.R.

1991-04-01

290

Power law relaxation in a complex system: Omori law after a financial market crash  

Microsoft Academic Search

We study the relaxation dynamics of a financial market just after the occurrence of a crash by investigating the number of times the absolute value of an index return is exceeding a given threshold value. We show that the empirical observation of a power law evolution of the number of events exceeding the selected threshold (a behavior known as the

Fabrizio Lillo; Rosario N. Mantegna

2001-01-01

291

Power-law relaxation in a complex system: Omori law after a financial market crash  

Microsoft Academic Search

We study the relaxation dynamics of a financial market just after the occurrence of a crash by investigating the number of times the absolute value of an index return is exceeding a given threshold value. We show that the empirical observation of a power law evolution of the number of events exceeding the selected threshold (a behavior known as the

F. Lilloand; Rosario N. Mantegna

2003-01-01

292

A continuum Damage Approach of Asphalt Concrete Fatigue Tests  

Microsoft Academic Search

To forecast pavement fatigue cracking, fatigue performances of asphalt mixtures are assessed us- ing laboratory cyclic fatigue tests. A damage model is implemented to predict the behavior of asphalt mixtures during these tests. Under sinusoidal loading, the evolution of the complex modulus of the ma- terial is defined as the damage variable associated to a microcracking mechanism. Its evolution during

Didier Bodin; Gilles Pijaudier-Cabot; Chantal de La Roche; Jean-Michel Piau

293

Newton's Law of Gravitation  

NSDL National Science Digital Library

The two activities included in this guide introduce students to the principles behind Newton's Law of Gravitation and help students learn aspects of the law in an interesting and engaging way. This guide provides teachers with background information pertaining to the activities, preparation suggestions for each activity, as well as material lists, and demonstrations. The activity guide assumes knowledge of Newton's Second Law of Motion, can be tailored for the level of the students, and can be completed individually or in groups. This is the last of four posters on Newton's Laws and a copy of the wallsheet intended to accompany these activities is available on this website.

294

Law.com  

NSDL National Science Digital Library

Describing itself as "a single, comprehensive destination for legal information, e-law services and legal products on the Web," this Website offers law students, legal professionals, business firms, and the general public news and information on the law. Lawyers will find here such items as the complete text of the latest edition of the American Lawyer with its listing of the top 100 law firms in the country. Law students can take advantage of features about schools, transferring, and recruiting, as well as links to professional associations. Businesses can find news and analysis of recent issues in business law as well as updated, annotated links to business law sites. For the public, the site offers news and analysis on prominent legal issues, such as recent Supreme Court decisions and the Wisconsin suit against the EPA over formulated gasoline. In addition, an online Real Life Dictionary of the Law gives accessible definitions to over 3,000 common legal terms. The search engine for the site draws on a surprisingly extensive archive -- for instance, we received more than 350 returns for "bankruptcy" -- making this site also a manageable resource for legal research, especially for practicing lawyers, journalists, and the general public. While this is a commercial site offering to sell law books, pamphlets, multimedia materials, and various online services, there is a considerable collection of free materials for users.

295

Bullying Policies and Laws  

MedlinePLUS

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

296

German Law Archive  

NSDL National Science Digital Library

Maintained by Gerhard Dannemann of the Centre for the Advanced Study of European and Comparative Law at University of Oxford, this site features cases, literature, and bibliographies on German law. Documents contained in the archive are organized in four sections: Judgments and other decisions by German courts; Statues: Acts of Parliament and statutory instruments; Literature on German law; and Bibliographies on German law. Additional resources include an internal search engine and related links. Some of the sections are still under development, and information for potential contributors to the archive is provided.

297

Federal Law Enforcement Statistics  

NSDL National Science Digital Library

Supplies census statistics about federal employees with law enforcement authority. Provides additional information about the functionality, budget, expenditures, and staffing of federal crime labs and police departments.

Justice, U. S.

298

School Law Update...Preventive School Law.  

ERIC Educational Resources Information Center

A wide variety of contemporary legal issues are addressed in the 15 separate papers that make up this volume. The introductory chapter by William C. Bednar, Jr. provides a broad-based rationale for "Preventive School Law." Chapters 2 and 3, both by Gerald A. Caplan, review "Current Issues in Reduction-in-Force" and "First Amendment Claims by…

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

299

Evolution of vortex knots  

NASA Astrophysics Data System (ADS)

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.

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

1999-07-01

300

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).

301

Information Law and Copyright.  

ERIC Educational Resources Information Center

Because of information law's inability to keep up with rapid changes in information technology and impreciseness of the law, copyrighting of databases poses unique problems. Interpretation of fair use doctrine, privately owned computer "downloading," impact of federal electronic filing, and questions concerning information businesses need to be…

Marx, Peter A.

1986-01-01

302

Reinventing Howard's Law School.  

ERIC Educational Resources Information Center

Describes efforts by Alice Gresham Bullock, dean of the Howard University School of Law, to improve the school (including building a new library and improving relations with faculty) and restore Howard to its previous stature as a leader in civil rights law. (EV)

Glenn, Gwendolyn

2001-01-01

303

Know Your Laws. Spanish.  

ERIC Educational Resources Information Center

This Spanish language version of "Know Your Laws" consists of 24 self-contained modules designed to acquaint the Florida adult student with laws she/he will meet in everyday life; fundamentals of local, state, and federal governments; and the criminal and juvenile justice systems. (The 130 objectives are categorized in the first three levels of…

Watson, Joan Q.; Ackerson, Leonor

304

Scaling Laws for SGEMP  

Microsoft Academic Search

Scaling laws for the nonlinear system-generated electromagnetic pulse (SGEMP) problem are defined and resulting implications for theory and experiments are explored. The scaling laws are used to present calculations in a scaled format which permits display of responses to a wide range of variations in fluence, spectrum, pulse width, and characteristic dimension. Interesting trends in the solutions as a function

A. J. Woods; E. P. Wenaas

1976-01-01

305

Social Studies: Law Education.  

ERIC Educational Resources Information Center

Reviews 11 series, texts, supplements, kits, and professional references for law instruction, including civil and criminal law, the Bill of Rights, and controversial legal issues: arson, gun control, capital punishment, and euthanasia. While all grade levels are covered, the emphasis is on secondary-level materials. (SJL)

Curriculum Review, 1979

1979-01-01

306

Teaching Information Technology Law  

ERIC Educational Resources Information Center

In this paper we discuss an approach to the teaching of information technology law to higher education computing students that attempts to prepare them for professional computing practice. As information technology has become ubiquitous its interactions with the law have become more numerous. Information technology practitioners, and in particular…

Taylor, M. J.; Jones, R. P.; Haggerty, J.; Gresty, D.

2009-01-01

307

Pop Goes the Law  

ERIC Educational Resources Information Center

The Law School Admission Council recently reported that applications were heading toward a 30-year low, reflecting, as a "New York Times" article put it, "increased concern over soaring tuition, crushing student debt, and diminishing prospects of lucrative employment upon graduation." Since 2004 the number of law-school applicants has dropped from…

Harper, Steven J.

2013-01-01

308

Law Related Education.  

ERIC Educational Resources Information Center

This journal edition focuses upon the many resources for teachers to draw upon in order to infuse law-related education (LRE) into their classrooms. Isidore Starr explains the reasons behind the LRE movement, while Mabel McKinney-Browning describes the existing American Bar Association's programs in LRE. Judith Zimmer covers the Street Law

Maslow, R., Ed.; Kirchgaessner, R., Ed.

1989-01-01

309

Science and the Law.  

ERIC Educational Resources Information Center

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)

Kennedy, Donald; Merrill, Richard A.

2000-01-01

310

Laws of data refinement  

Microsoft Academic Search

A specification language typically contains sophisticated data types that are expensive or even impossible to implement. Their replacement with simpler or more efficiently implementable types during the programming process is called data refinement. We give a new formal definiton of data refinement and use it to derive some basic laws. The derived laws are constructive in that used in conjunction

Joseph M. Morris

1989-01-01

311

Laws for Young Mountaineers.  

ERIC Educational Resources Information Center

This booklet introduces secondary grade students to the criminal laws of West Virginia. It can easily be adapted and used by educators in other states. The authors believe that young people must recognize and understand these laws and the mechanisms which society uses to implement and enforce them if they are to function as an integral, important,…

Kanawha County Board of Education, Charleston, WV.

312

Lotka's Law Revisited.  

ERIC Educational Resources Information Center

Discusses the literature that has become associated with Lotka's Law of Scientific Productivity (a general theoretical estimate of author productivity in the sciences) and attempts to identify the important factors of Lotka's original methodology that should be considered when attempting to test applicability of Lotka's Law. Forty-seven references…

Potter, William Gray

1981-01-01

313

Physics Flashlets: Kepler's Laws  

NSDL National Science Digital Library

This simulation illustrates Kepler's Second Law, that orbits sweep out equal areas during equal intervals of time, for any part of the orbit. The user can choose from three buttons between circular or increasingly elliptical orbits to observe that the law holds in all cases.

Fowler, Michael; Welch, Heather

2008-10-05

314

The law and neuroscience.  

PubMed

Some of the implications for law of recent discoveries in neuroscience are considered in a new program established by the MacArthur Foundation. A group of neuroscientists, lawyers, philosophers, and jurists are examining issues in criminal law and, in particular, problems in responsibility and prediction and problems in legal decision making. PMID:18995814

Gazzaniga, Michael S

2008-11-01

315

Ohm's Law 2  

NSDL National Science Digital Library

In this extension to the Ohm's Law I activity, students observe just how much time it takes to use up the "juice" in a battery, and if it is better to use batteries in series or parallel. This extension is suitable as a teacher demonstration and may be started before students begin work on the Ohm's Law I activity.

K-12 Outreach Office,

316

Nanotechnology and the Law  

NASA Astrophysics Data System (ADS)

Law and nanotechnology form a vast subject. The aim here will be to examine them from the societal standpoint of nanoethics, if necessary without due reference to the work that has been undertaken. For while law differs from ethics, as we shall attempt to explain throughout this reflection, it must also be studied in its relationship with social realities.

Desmoulin-Canselier, Sonia; Lacour, Stéphanie

317

SIMULATION OF PROGRESSIVE DAMAGE IN BOLTED COMPOSITE JOINTS  

Microsoft Academic Search

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 \\

Hannes Koerber; Pedro P. Camanho

318

Damage and fracture simulation during the extrusion processes  

Microsoft Academic Search

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

Ridha Hambli; Daniel Badie-Levet

2000-01-01

319

International resources law  

SciTech Connect

This book covers: Historical origins of civil code legal systems; Modern civil law practice for mineral lawyers; Treaties and agreements for protection of international investments; Europe 1992-toward a single energy market; Dispute resolution in international agreements; Assessment of political risk; Reducing political risk; Protecting mineral investments from upheaval in developing countries; Typical world petroleum arrangements; government take in the Pacific Rim - Papua New Guinea; Mineral base of the USSR and prospects of investment; International taxation for the mining practitioner; Tax considerations - branch versus subsidiary; Doing business in the host country - nontax considerations; Impact of host-country laws on operations and profits; Mineral development and native rights - New Zealand; Designing the investment vehicle: mining; International oil and gas joint ventures; Selected U.S. laws with extraterritorial effect; U.S. tax and securities laws applied to foreign joint venturers; and Extraterritorial effect of U.S. laws.

Not Available

1991-01-01

320

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.

321

Impact crater scaling laws  

NASA Technical Reports Server (NTRS)

Impact craters are numerous on planetary bodies and furnish important information about the composition and past histories of those bodies. The interpretation of that information requires knowledge about the fundamental aspects of impact cratering mechanics. Since the typical conditions of impacts are at a size scale and velocity far in excess of experimental capabilities, direct simulations are precluded. Therefore, one must rely on extrapolation from experiments of relatively slow impacts of very small bodies, using physically based scaling laws, or must study the actual cases of interest using numerical code solutions of the fundamental physical laws that govern these processes. A progress report is presented on research on impact cratering scaling laws, on numerical studies that were designed to investigate those laws, and on various applications of the scaling laws developed by the author and his colleagues. These applications are briefly reviewed.

Holsapple, K. A.

1987-01-01

322

Florida Law Collections  

NSDL National Science Digital Library

The Florida Law Collections document the laws and legal heritage of Florida through a wide range of texts digitized from the holdings of the University of Florida's Lawton Chiles Legal Information Center, the State Library, and Archives of Florida, and several other key institutions. Specifically, the collection includes issues of the Journal of the Florida House of Representatives, the Florida Historical Legal Documents collection, a Florida Water Law collection that is particularly noteworthy, as well as other general texts on Florida laws, the legislative process, and government. Given the debates over water rights and usage throughout the state, the Water Law collection is a real find, and visitors can search over 7300 documents within the collection. From the homepage, visitors can perform advanced searches and also look over recently added items. Finally, visitors can also sign up to receive their RSS feed and contact the site administrators with any additional queries they might have.

323

Stanford Technology Law Review  

NSDL National Science Digital Library

This site, sponsored by the Stanford University Law School, among others, "publishes articles, book reviews, and working papers within the intersection of law, policy, and science/technology." At present one article and three working papers are available. They cover topics such as the Reno v. ACLU decision, who the makers of law in cyberspace should be, how cyberlaw might be different from other law, and changes in evidentiary privileges as a result of the advances in telecommunications. Authors range from litigation counsels at MCI to Eugene Volokh and Lawrence Lessig, University of California-Los Angeles and Harvard University Law professors respectively. The site also contains a virtual symposium on "cloning sheep, cloning people." Note that papers and articles are available in multiple formats.

1997-01-01

324

Entropy, irreversibility and evolution.  

PubMed

The Second Law of Thermodynamics is investigated with respect to its value as an indicator of the direction of the evolutionary process. Non-thermodynamic entropy concepts and possible errors in the use of thermodynamic entropy are discussed. The importance of genuine thermodynamic potentials and their correct application for understanding processes is emphasized. There is no direct connection between evolutionary events such as speciation and thermodynamic entropy changes; the irreversibility of evolution is not a consequence of thermodynamic irreversibility. PMID:7564399

Berry, S

1995-07-12

325

A theoretical model of grainsize evolution during deformation  

NASA Astrophysics Data System (ADS)

Lithospheric shear localization, as occurs in the formation of tectonic plate boundaries, is often associated with diminished grainsize (e.g., mylonites). Grainsize reduction is typically attributed to dynamic recrystallization; however, theoretical models of shear-localization arising from this hypothesis are problematic since (1) they require the simultaneous action of two exclusive creep mechanisms (diffusion and dislocation creep), and (2) the grain-growth ("healing") laws employed by these models are derived from static grain-growth or coarsening theory, although the shear-localization setting itself is far from static equilibrium. We present a new first-principles grained-continuum theory which accounts for both coarsening and damage-induced grainsize reduction. Damage per se is the generic process for generation of microcracks, defects, dislocations (including recrystallization), subgrains, nucleii and cataclastic breakdown of grains. The theory contains coupled statistical grain-scale and continuum macroscopic components. The grain-scale element of the theory prescribes both the evolution of the grainsize distribution, and a phenomenological grain-growth law derived from non-equilibrium thermodynamics; grain-growth thus incorporates the free energy differences between grains, including both grain-boundary surface energy (which controls coarsening) and the contribution of deformational work to these free energiesconservation and positivity of entropy production provide the phenomenological law for the statistical grain-growth law. We identify four potential mechanisms that affect the distribution of grainsize; two of them conserve the number of grains but change their relative masses and two of them change the number of grains by sticking them together or breaking them. In the limit of static equilibrium, only the two mechanisms that increase the average grainsize are allowed by the second law of thermodynamics. The first one is a diffusive mass transport from small grains to large grains that captures the essential component of normal grain-growth theories. The second one is the aggregation of grains. With the inclusion of nonstatic/nonequilibrium conditions, the theory predicts two mechanisms for which the thermodynamic requirement of entropy positivity always imposes large grains to shrink and small ones to grow. A first damage mechanism opposite to diffusion, tends to homogenize the distribution of grainsize around its initial average grainsize. A second damage mechanism favors the creation of small grains by division of larger grains. This second mechanism reduces the average grainsize with time. The competition between the two coarsening mechanisms, the damage-induced grain homogenization and the damage-induced grain reduction controls the general evolution of the grainsize population. Under uniform and constant shear, and assuming than grains cannot stick together, the average grainsize is related to the energy dissipated during the deformation (in agreement with Austin and Evans, 2007). The prediction of this theory fits satisfactorily with the available observations and we will discuss the implications of this model for large scale geodynamics.

Ricard, Y.; Bercovici, D.; Rozel, A.

2007-12-01

326

Darwinian Evolution and Fractals  

NASA Astrophysics Data System (ADS)

Did nature's beauty emerge by chance or was it intelligently designed? Richard Dawkins asserts that evolution is blind aimless chance. Michael Behe believes, on the contrary, that the first cell was intelligently designed. The scientific evidence is that nature's creativity arises from the interplay between chance AND design (laws). Darwin's ``Origin of the Species,'' published 150 years ago in 1859, characterized evolution as the interplay between variations (symbolized by dice) and the natural selection law (design). This is evident in recent discoveries in DNA, Madelbrot's Fractal Geometry of Nature, and the success of the genetic design algorithm. Algorithms for generating fractals have the same interplay between randomness and law as evolution. Fractal statistics, which are not completely random, characterize such phenomena such as fluctuations in the stock market, the Nile River, rainfall, and tree rings. As chaos theorist Joseph Ford put it: God plays dice, but the dice are loaded. Thus Darwin, in discovering the evolutionary interplay between variations and natural selection, was throwing God's dice!

Carr, Paul H.

2009-05-01

327

[Teaching about Law and Literature].  

ERIC Educational Resources Information Center

This issue of "Focus on Law Studies" contains a special emphasis on teaching about law and literature, in the form of the following six articles: "Law and Literature: New Combinations in Teaching" (John Paul Ryan); "Teaching Law and American Literature" (Janet Eldred); "Teaching Law with Sacco, Vanzetti, and the Rosenbergs" (Susan N. Herman); Ann…

Ryan, John Paul, Ed.

1993-01-01

328

GENERAL STRUCTURE OF THE LAW  

Microsoft Academic Search

Economic theory can provide insight into the general structure of the law and the organization of topics in this encyclopedia. After arguing that all of law is contract law, I show how economics can be used to explain the choice between criminal law and tort law, liability rules and property rights, prior regulation and post liability, restitution and torts, and

Donald Wittman

329

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.

1994-01-01

330

Ideal Gas Laws  

NSDL National Science Digital Library

This lab manual contains descriptions of a series of laboratories covering the ideal gas laws and ideal gas processes. These experiments are designed for introductory high school and college introductory physics, chemistry, and engineering courses. Each experiment includes the intended audience, learning goals, and a short introduction to the physics. The experiments include Boyleâs Law, work done in an isothermal process, adiabatic processes, thermodynamic cycles, and the heat capacity of a gas. These labs are designed for an adiabatic gas law apparatus developed at Andrews University.

Kutzner, Mickey; Wong, Peter

2011-11-18

331

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

ERIC Educational Resources Information Center

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)

Costonis, John J.

2002-01-01

332

Law Enforcement and the Library.  

ERIC Educational Resources Information Center

Presents information on law enforcement relating to library crimes. Discusses jurisdiction, reporting a loss, law enforcement response, law enforcement's expectations, suspects, publicity, the aftermath, and testimony in court. (AEF)

Clark, Edward F.

1998-01-01

333

The matching law  

PubMed Central

The matching law may be viewed either as an empirical generalization, and therby subject to disproof, or as part of a system of equations used to define the utility (“value”) of a reinforcer. In the latter case it is tautologous, and not subject to disproof within the defining context. A failure to obtain matching will most often be a signal that the independent variables have not been properly scaled. If, however, the proper transformations have been made on the independent variables, and matching is not obtained, the experimental paradigm may be outside the purview of the matching law. At that point, reinterpretations or revisions of the law are called for. The theoretical matching law is but one of many possible ways to define utility, and it may eventually be rejected in favor of a more useful definition.

Killeen, Peter

1972-01-01

334

Assistive Technology Laws  

MedlinePLUS

... the Rehabilitation Act requires that all electronic and information technologies developed and used by any Federal government agency ... gov/telecom.html Federal Government Procurement of Accessible Information Technology Public Law 105-220 section 408 [29 USC ...

335

Civil Law Study Guide.  

National Technical Information Service (NTIS)

This study guide is intended to be a convenient reference for use by Navy and Marine Corps personnel on civil law subjects. Those subjects include, inter alia, JAG Manual investigations, enlisted administrative separations, officer personnel matters, rela...

1987-01-01

336

Laws of Motion  

NSDL National Science Digital Library

The representation depicts a truck with a ladder on its roof stopping quickly so that the ladder is thrown from the top of the truck. The representation is contained within a slide show explaining Newton's 1st Law of Motion.

337

Model State Idling Law.  

National Technical Information Service (NTIS)

In May, 2004, at the National Idle Reduction Planning Conference in Albany, New York, representatives from the trucking industry identified the inconsistent pattern and design of state and local vehicle idle restriction laws as a barrier to greater implem...

2006-01-01

338

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."

339

Newton's Laws of Motion  

NSDL National Science Digital Library

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.

Stern, David P.

2004-10-09

340

What Is Benford's Law?  

ERIC Educational Resources Information Center

The surprising property of many data sets that their first significant digits follow Benford's Law provides examples that can pique and hold students' interest. Several ideas for student activities are presented.

Bradley, Jonathan R.; Farnsworth, David L.

2009-01-01

341

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.

342

Distracted Driving Laws  

MedlinePLUS

... 3 restrict school bus drivers from texting. Crash Data Collection: Nearly all states include at least one category ... Criteria (MMUCC) guideline provides best practices on distraction data collection. Preemption Laws: Many localities have passed their own ...

343

Nonlocal Damage Gradient Model for Fracture Characterization of Aluminum Alloy  

Microsoft Academic Search

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

Chi L. Chow; Jianghui Mao; Jie Shen

2011-01-01

344

Western ground water law  

SciTech Connect

The bulk of western ground-water law is currently imposed at the state and local levels, and is highly variable in its technical provisions. Most ground water law is of recent origin (largely since the end of World War II) and continues to evolve through legislative enactments and judicial decisions. The principal purposes of ground water law are: (1) to regulate the rate of depletion to aquifers whose natural and artificial recharge is insufficient; (2) to regulate the rate of depletion to aquifers which supply or support the flow of surface water to prior vested ownership rights which take from streams, lakes, and springs; (3) to protect aquifers from pollution; and (4) to regulate the extraction or injection of ground water in areas prone to geologic instability. The law which attempts to achieve these objectives is a patchwork of federal constitutional principles and judicial doctrine; federal statutes and subsidiary regulations; state constitutional and statutory provisions developed from judicial interpretation; state common law; local ordinances and regulations. Because of the extent and complexity of this body of law, clear-cut answers to all but the most routine and narrow questions are difficult to ascertain. This is due partly to the fact that such questions arose infrequently prior to the time ground water assumed a major role in supplying the water needs of the west, and partly from earlier incomplete and faulty understandings of ground-water hydrology by the courts.

Not Available

1982-03-01

345

Water law and the development of geothermal resources  

SciTech Connect

A review of 14 western states reveals a diversity of legal approaches to the water problems associated with the geothermal fluids of surface and groundwaters. State variations in the application and enforcement of water and property laws are presented in the appendix. Recommendations to geothermal developers include having a thorough knowledge of state water laws and participation in the formulation of state regulatory processes. To facilitate new geothermal development, holders of prior water rights should have the burden of proving interference and damage. Courts should wait for state legislatures to deal specifically with geothermal issues rather than ruling on the basis of past water law. 44 references. (DCK)

Olpin, O.; Thompson, B.H.

1982-01-01

346

Phenomenological approach to mechanical damage growth analysis.  

PubMed

The problem of characterizing damage evolution in a generic material is addressed with the aim of tracing it back to existing growth models in other fields of research. Based on energetic considerations, a system evolution equation is derived for a generic damage indicator describing a material system subjected to an increasing external stress. The latter is found to fit into the framework of a recently developed phenomenological universality (PUN) approach and, more specifically, the so-called U2 class. Analytical results are confirmed by numerical simulations based on a fiber-bundle model and statistically assigned local strengths at the microscale. The fits with numerical data prove, with an excellent degree of reliability, that the typical evolution of the damage indicator belongs to the aforementioned PUN class. Applications of this result are briefly discussed and suggested. PMID:18999489

Pugno, Nicola; Bosia, Federico; Gliozzi, Antonio S; Delsanto, Pier Paolo; Carpinteri, Alberto

2008-10-01

347

A two-scale damage model with material length  

NASA Astrophysics Data System (ADS)

The Note presents the formulation of a class of two-scale damage models involving a micro-structural length. A homogenization method based on asymptotic developments is employed to deduce the macroscopic damage equations. The damage model completely results from energy-based micro-crack propagation laws, without supplementary phenomenological assumptions. We show that the resulting two-scale model has the property of capturing micro-structural lengths. When damage evolves, the micro-structural length is given by the ratio of the surface density of energy dissipated during the micro-crack growth and the macroscopic damage energy release rate per unit volume of the material. The use of fracture criteria based on resistance curves or power laws for sub-critical growth of micro-cracks leads to quasi-brittle and, respectively, time-dependent damage models. To cite this article: C. Dascalu, C. R. Mecanique 337 (2009).

Dascalu, Cristian

2009-09-01

348

Modeling history to analyze software evolution  

Microsoft Academic Search

SUMMARY The histories of software systems hold useful information when reasoning about the systems at hand or when reasoning about general laws of software evolution. Over the past 30 years more and more research has been spent on understanding software evolution. However, the approaches developed so far do not rely on an explicit meta- model, and thus, they make it

Tudor Gîrba; Stéphane Ducasse

2006-01-01

349

Evolution of the information in the universe  

Microsoft Academic Search

Information in the universe evolves according to a nonlinear law, which results from a combination of nonlinear dynamics and quantum theory. The Kolmogoroff-Sinai entropy rate of the universe evolves in inverse proportion to the temperature. Since the evolution of temperature is known from standard cosmology, the time dependence of the universal entropy rate can be determined and the temporal evolution

Rudolf A. Treumann

1993-01-01

350

Evolution of the information in the universe  

Microsoft Academic Search

Information in the universe evolves according to a nonlinear law, which results from a combination of nonlinear dynamics and quantum theory. The Kolmogoroff-Sinai entropy rate of the Universe evolves in inverse proportion to the temperature. Since the evolution of temperature is known from standard cosmology, the time dependence of the universal entropy rate can be determined and the temporal evolution

Rudolf A. Treumann

1993-01-01

351

Kepler's Laws, Newton's Laws, and the Search for New Planets  

Microsoft Academic Search

Introduction. One of the high points of elementary calculus is the derivation of Ke- pler's empirically deduced laws of planetary motion from Newton's Law of Gravity and his second law of motion. However, the standard treatment of the subject in calcu- lus books is flawed for at least three reasons that I think are important. First, Newton's Laws are used

Robert Osserman

352

Rediscovering Kepler's laws using Newton's gravitation law and NASA data  

NASA Astrophysics Data System (ADS)

Kepler's three laws of planetary motion were originally discovered by using data acquired from Tycho Brache's naked eye observations of the planets. We show how Kepler's third law can be reproduced using planetary data from NASA. We will also be using Newton's Gravitational law to explain why Kepler's three laws exist as they do.

Springsteen, Paul; Keith, Jason

2010-03-01

353

Rediscovering Kepler's laws using Newton's gravitation law and NASA data  

Microsoft Academic Search

Kepler's three laws of planetary motion were originally discovered by using data acquired from Tycho Brache's naked eye observations of the planets. We show how Kepler's third law can be reproduced using planetary data from NASA. We will also be using Newton's Gravitational law to explain why Kepler's three laws exist as they do.

Paul Springsteen; Jason Keith

2010-01-01

354

Consequences of Lotka's Law for the Law of Bradford.  

ERIC Educational Resources Information Center

After discussion of the equivalency of the information laws of Bradford, Leimkuhler, Lotka, and Mandelbrot, aberrations from Leimkuhler's law (including "Groos droop" as encountered in practice) are studied. Other aberrations of Leimkuhler's law are explained, starting from generalization of verbal formulation of Bradford's Law. (18 references)…

Egghe, L.

1985-01-01

355

Power-law decreasing in solutions of the Boltzmann equation  

NASA Astrophysics Data System (ADS)

We analyze the evolution of distribution functions with a power-law decrease at large energies. We apply the temperature transform approach and show that these decays correspond to branch points of the transformed function. For the very hard particle (VHP) model we find that an initial condition with power-law decrease relaxes to an exponential one immediately for t > 0. For Maxwell models we study the displacement of the branch points and find that the power-law decrease is preserved as time elapses.

Zanette, D.; Garibotti, C. R.; Barrachina, R. O.

1987-02-01

356

Observation of mammalian similarity through allometric scaling laws  

Microsoft Academic Search

We discuss the problem of observation of natural similarity in skeletal evolution of terrestrial mammals. Analysis is given by means of testing of the power scaling laws established in long-bone allometry, which describe development of bones (of length L and diameter D) with body mass in terms of the growth exponents, e.g., ?=dlogL\\/dlogD. The bone-size evolution scenario given three decades

Valery B. Kokshenev

2003-01-01

357

An Energy-based Damage Model for Concrete Structures under Cyclic Loading  

Microsoft Academic Search

An anisotropic damage model is developed by introducing nonlinear unloading\\/linear reloading branches on the principal axis of damage to simulate the hysteretic behaviors of concrete structures subjected to cyclic loading. The nonlinear unloading branch is defined as a power function and an energy-based evolution rule of damage is implemented into the definition of linear reloading one. Two independent damage variables,

Long Yuchuan; XU Shaoqian; GAO Xuechao

2011-01-01

358

Duhaime's Law Dictionary  

NSDL National Science Digital Library

Part of a Canadian site created and maintained by a solicitor of British Columbia with the express purpose of "giving the law back to the people," this dictionary offers clear, concise definitions of many legal terms that anyone who finds themselves engaged with issues of civil or criminal justice is likely to need to know. While some of the terms are clearly applicable to the system of justice in which solicitor Duhaime practices, the vast majority are generic to Western law. A link is also offered to Duhaime.org, the parent site, which features a plethora of materials for educating oneself in the law, especially if one is dealing with the Canadian justice system.

359

Biodiversity Laws: State Experiences  

PubMed

/ The Western Governors' Association (WGA) includes both the public lands states with their issues and the plains states, which are 98% privately owned. WGA deals with most legislation affecting biodiversity, whether the effect is direct or tangential. It will probably not be possible, or desirable, for one entity to be in charge of biodiversity conservation. The Endangered Species Act, public lands laws, agricultural laws, water law, environmental laws, and funding legislation all affect biodiversity conservation and the responsibility for it. None of them on their own are enough, and most can cause harmful unintended consequences for biodiversity. The experience of western states in developing consensus principles for reauthorization of the Endangered Species Act provides an example of common-sense ways to improve management of biodiversity, notwithstanding the complexity and large stakes involved. The WGA's proposed changes call for increasing the role of states, streamlining the act, and increasing certainty for landowners and water users.To achieve sustainable conservation for biodiversity, the better question is not "Who is/should be in charge?", it is "How do we get this done?" To answer this, we need goals, guidance, and bottom lines from federal laws, and management and oversight at the state level, but they all need to support local on-the-ground partnerships. Sustainable conservation requires the active participation of those who live there. WGA's experience in coordinating the Great Plains Partnership as well as its work with watershed efforts shed light on what to expect. Multilevel partnerships are not easy and require a different way of doing business. The ad hoc, site-specific processes that result do not lend themselves to being legislated, fit into organizational boxes, or scored on a budget sheet. They do require common sense and a long-term perspective.KEY WORDS: Biodiversity; Partnerships; Environmental laws; Endangered Species Act; Conservation; Local empowerment PMID:8895414

CLARK

1996-11-01

360

The trespasses of property law.  

PubMed

The purpose of this article is to identify a limit to the appropriate application of property law to the use and storage of bodily material. I argue here that property law ought to be limited to protecting 'contingent rights' and that recent cases where property rights have been recognised in semen represent the application of property law beyond this limit. I also suggest how the law ought to develop in order to avoid the overextensive use of property law. PMID:23842078

Wall, Jesse

2014-01-01

361

International Water Law Project  

NSDL National Science Digital Library

As clean water has increasingly become a resource subject to scarcity, international politics and law have become involved with the issues of access to and maintenance of water sources. This site provides comprehensive information on the subject, featuring full texts of the major diplomatic documents, including rules on international groundwaters and rivers agreed upon at UN conferences in Helsinki and Seoul, treaty drafts, regional agreements as well as international case law, an extensive bibliography, and links to related sites. The site was conceived and developed by Gabriel Eckstein in conjunction with The World's Water project of the Pacific Institute.

Eckstein, Gabriel.

362

Kepler's Second Law  

NSDL National Science Digital Library

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.

Stern, David

363

The past, present, and future of software evolution  

Microsoft Academic Search

Change is an essential characteristic of software development, as software systems must respond to evolving requirements, platforms, and other environmental pressures. In this paper, we discuss the concept of software evolution from several perspectives. We examine how it relates to and differs from software maintenance. We discuss insights about software evolution arising from Lehmanpsilas laws of software evolution and the

Michael W. Godfrey; Daniel M. German

2008-01-01

364

Education Law. Second Edition.  

ERIC Educational Resources Information Center

This second edition of this reference guide provides a survey of some of the major legal problems that confront policymakers and school administrators. It contains landmark cases and other cases that best illustrate major principles of education law, along with summaries, discussions, and analyses of the cases. Edited cases are integrated into…

Imber, Michael; van Geel, Tyll

365

The Laws List  

NSDL National Science Digital Library

This site is a dictionary of physics and astronomy. Users can look up laws, rules, terms and constants related to physics in pages listed by letter. The site is not a complete reference, but it is a useful resource for introductory physics.

Francis, Erik

2004-11-28

366

State Infertility Insurance Laws  

MedlinePLUS

... their teachings and beliefs. (Illinois Compiled Statutes Annotated, Chapter 215, Sections 5/356m and 125/5-3). ... or cryopreservation of eggs. (Annotated Laws of Massachusetts, Chapters 175,§ 47H; 176A,§8K;176B,§4J; and l76G,§ ...

367

Strike Laws, Not Children.  

ERIC Educational Resources Information Center

In 1999, a coalition of child advocacy groups, the Canadian Foundation for Children, Youth, and the Law, challenged Section 43 of Canada's criminal code, which permits "reasonable force" in disciplining children. The heavily debated issue turns on judges' varied interpretations. A court decision is expected by year's end. (MLH)

Robertson, Heather-Jane

2000-01-01

368

School Law Update, 1985.  

ERIC Educational Resources Information Center

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)…

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

369

Environmental Law II.  

ERIC Educational Resources Information Center

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…

Continuing Legal Education in Colorado, Inc., Denver.

370

Metrics for Law Enforcement.  

ERIC Educational Resources Information Center

Designed to meet the job-related metric measurement needs of students interested in law enforcement, this instructional package is one of two for the public service occupations cluster, part of a set of 55 packages for metric instruction in different occupations. The package is intended for students who already know the occupational terminology,…

Cooper, Gloria S., Ed.; Magisos, Joel H., Ed.

371

Law in Outer Space.  

ERIC Educational Resources Information Center

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,…

Schmidt, William G.

1997-01-01

372

Relativistic Kepler's third law  

Microsoft Academic Search

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

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

1986-01-01

373

Knowledge and social laws  

Microsoft Academic Search

In this paper we combine existing work in the area of social laws with a framework for reasoning about knowledge in multi-agent systems. The unifying framework in which this is done is based on Alternating-time Temporal Logic (ATL), to which semantics we add epistemic accessibility relations (to deal with the knowledge), actions (in order to naturally talk about allowed and

Wiebe van der Hoek; Mark Roberts; Michael Wooldridge

2005-01-01

374

Law as Focus.  

ERIC Educational Resources Information Center

Shows how teachers can increase students' general appreciation of literature and improve students' writing skills by studying literature with legal issues and images of the law. Cites several examples of such literature, including Geoffrey Chaucer's "Canterbury Tales," William Shakespeare's "Measure for Measure," and Jonathan Swift's "Gulliver's…

Blythe, Joan Heiges

1989-01-01

375

National Indian Law Library  

NSDL National Science Digital Library

The National Indian Law Library (NILL) has worked for over three decades to bring together key resources for Native Americans and their advocates in the field of legal scholarship and service. Today it remains the only entity that offers a comprehensive vision of past and present tribal governmental documents from across the United States. The NILL is based in Boulder, Colorado and its website provides selected documents, information on ongoing activities and the very useful Indian Law News Bulletins. These bulletins are published almost every week and offer succinct and timely information about new developments in Indian Law. Visitors can search through the archives of these bulletins back to 1998, or look through the bulletins for links to germane legal briefs. This same area contains links to digests that cover activities in state courts, federal trial courts, and law review journal articles. Users shouldn't miss the Research By Topic area, which contains links that deal with 20 different themes, including tribal education, health & human services, sacred sites, prisoners' issues, and child welfare.

376

Chemistry and the law.  

PubMed

The Chemistry and the Law Division of the American Chemical Society met in San Diego in March 2012. The divisional meeting was attended by patent attorneys, patent analysts and scientists who are all united by the business need to effectively deal with patent prosecution, patent research, litigation and licensing. This report highlights some of the presentations from the divisional sessions. PMID:24236835

Grant, James L

2012-07-01

377

Stoke's Law Problem Set  

NSDL National Science Digital Library

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.

Headley, Rachel

378

Boyle's Law Experiment.  

ERIC Educational Resources Information Center

Suggests that ideal experiments fit into course time constraints and be meaningful, relevant to course content, safe, inexpensive, simple, reproducible, and easy to set up/maintain. Describes a Boyle's Law experiment that uses a minimum of equipment and meets the foregoing criteria. Apparatus used, procedures, and safety precautions are…

Hermens, Richard A.

1983-01-01

379

A Boyle's Law Demonstrator.  

ERIC Educational Resources Information Center

The usual apparatus for demonstrating Boyle's law produces reasonably accurate results, but is not impressive as a demonstration because students cannot easily appreciate the change in pressure. An apparatus designed to produce a more effective demonstration is described. Procedures employed are also described. (JN)

Sathe, Dileep V.

1984-01-01

380

German law: the differences.  

PubMed

Medical device regulations in Germany are changing. The first amendment of the Medical Device Law, the MPG, is in preparation. Four decrees on medical devices are also being discussed by the Bundesrat, the Federal Council. This article summarizes what manufacturers, distributors and users should know about the German device regulations. PMID:10174630

Müller-Lierheim, W G

1997-11-01

381

On the psychophysical law  

Microsoft Academic Search

The general psychophysical law is that equal stimulus ratios produce equal subjective ratios. A first-order approximation is a power function whose exponent varies from 0.3 (loudness) to 2.0 (visual flash rate). This holds for Class I (prothetic) or quantitative continua, distinguishable by 4 criteria: \\

S. S. Stevens

1957-01-01

382

Newton's Laws Demonstrations  

NSDL National Science Digital Library

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.

Rathjen, Don

2007-01-01

383

International Economic Law  

Microsoft Academic Search

As conflict and cooperation among states turn to an ever greater extent on economic issues, this fully updated and expanded second edition presents a comprehensive exploration of the legal foundations of the international economy. It not only examines the current status of the law, but also explores the origins, political tensions and development of outcomes that are often difficult to

Andreas F. Lowenfeld

384

Athletics and the Law.  

ERIC Educational Resources Information Center

This book answers questions concerning athletics and the law. The chapters include trends in litigation, disruptive behavior, the changing attitude of the court toward married athletes, training rules, and good conduct codes. They include the problem of athletic travel, the changing role of state athletic associations with their diverse rules,…

Appenzeller, Herb

385

THE INVERSE CARE LAW  

Microsoft Academic Search

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-

JULIAN TUDOR HART

386

Team Teaching School Law  

ERIC Educational Resources Information Center

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…

Vanko, John G.; Rogina, Raymond P.

2005-01-01

387

Physical Laws for Mechanobiology.  

National Technical Information Service (NTIS)

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, whe...

A. D. Freed

2007-01-01

388

Preventive Law Curriculum Guide.  

ERIC Educational Resources Information Center

This curriculum guide presents a context for preservice education and/or professional development in education law for teachers. Section 1, "Teacher Liability," discusses "Duty to Supervise,""Providing Reasonable Care,""Duty,""Preventing Student-to-Student Sexual Harassment,""Reporting Child Abuse,""Issuing Permission Slips,""Defense for…

Henderson, Martha V.; Gullatt, David E.; Hardin, Dawn T.; Jannik, Catherine; Tollett, John R.

389

AID and the law  

PubMed Central

The present state of the law is unsatisfactory. The exact effect on the marriage of the parties has not been decided although in English law if artificial insemination by donor (AID) takes place without consent that would appear to be a ground for divorce since 1969. The law regards a child born as a result of AID as illegitimate and draws no distinction between the case where the husband consents and where he does not. Theoretically, an offence is committed if the birth entry is falsified, presumably in cases where the husband consents. The AID child, like any other illegitimate child, has rights against the natural parents, but he is in a worse position than most illegitimate children, in that he may not have any information about his father. It is now possible to freeze sperm and so preserve it over longer periods. All the problems associated with AID are present also when sperm is preserved in banks, but if the law is in an unsatisfactory state in relation to AID this is even more true in relation to sperm banks. The main criticism of the Feversham Report (1960) could be that it recommended, broadly speaking, the `status quo' but scientific progress has now overtaken and left the Feversham findings well behind. What, therefore, is required is a full consideration of the subject of AID and, on the basis of that, some statutory code regulating all its aspects.

Cusine, D J

1975-01-01

390

Law, endowments, and finance  

Microsoft Academic Search

Using a sample of 70 former colonies, this paper assesses two theories regarding the historical determinants of financial development. The law and finance theory holds that legal traditions, brought by colonizers, differ in terms of protecting the rights of private investors vis-à-vis the state, with important implications for financial markets. The endowment theory argues that the disease environment encountered by

Thorsten Beck; Asli Demirgüç-Kunt; Ross Levine

2003-01-01

391

Law, Endowment, and Finance  

Microsoft Academic Search

This paper assesses two theories regarding the historical determinants of international differences in financial development. The law and finance theory holds that legal traditions differ in terms of the priority they attach to protecting the rights of private investors vis-a-vis the State and this has important implications for financial development. The endowment theory argues that the disease and geographical environment

Thorsten Beck; Asli Demirguc-Kunt; Ross Levine

2002-01-01

392

Yugoslav Enterprises Law.  

National Technical Information Service (NTIS)

Text is presented in English of Yugoslav federal enterprises law, originally published in Sluzbeni list at no. 77/78, 40/89, 46/90. Provisions cover social ownership, cooperative ownership, mixed ownership, and private ownership. Includes founding and man...

1990-01-01

393

Investigation of damage accumulation during unsteady low-cycle loading under stress control  

Microsoft Academic Search

Conclusions 1.It is proposed that the addition of relative unidirectional cumulative plastic strains (quasistatic damage) and relative cyclic strains (fatigue damage) be adopted for estimating the state of damage of cyclically anisotropic materials under symmetric stress control and asymmetric unsteady loading in the general case.2.Under a single change of loading regime the law of linear addition of relative lives gives

M. A. Daunis; R. A. Stasyunas

1976-01-01

394

Adhesive Characterization and Progressive Damage Analysis of Bonded Composite Joints  

NASA Technical Reports Server (NTRS)

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 indicate that the model is capable of predicting the interactions of damage modes that lead to the failure of the joint.

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

2014-01-01

395

Clearance of Nonlinear Flight Control Laws Using Hybrid Evolutionary Optimization  

Microsoft Academic Search

The application of two evolutionary optimisation methods, namely differential evolution and genetic algorithms, to t he clearance of nonlinear flight control laws for highly augmen ted aircraft is described. The algorithms are applied to the problem of evaluating a nonlinear handling qualities clearance cri terion for a simulation model of a high performance aircraft with a delta canard configuration and

Prathyush P. Menon; Jongrae Kim; Declan G. Bates; Ian Postlethwaite

2006-01-01

396

Modeling the densification of powder composites by power law creep  

Microsoft Academic Search

A model describing the densification under isotropic pressure of a powder composite, consisting of viscoplastic particles deforming by power law creep mixed with rigid inclusions of the same size, is presented. A description of the behavior of each type of contacts is first proposed, from which an expression for the densification rate of the mixture is deduced. The evolution of

Bouvard

1993-01-01

397

Antarctic implications of the new law of the sea  

Microsoft Academic Search

The impact of ideas adopted at the Third United Nations Conference on the Law of the Sea (UNCLOS III) on current discussions of Antarctica's future demonstrates how changes in one international regime can affect the evolution of another. By 1975, changed fish and oil markets had increased interest in Antarctic resources to the point where participants in the Antarctic Treaty

M. J. Peterson

1986-01-01

398

Toda lattice hierarchy and conservation laws  

NASA Astrophysics Data System (ADS)

Time evolutions of the Toda lattice hierarchies of Ueno and Takasaki are induced by Hamiltonians which are conservation laws for the original (one and two dimensional) Toda lattice obtained by Olive and Turok. Moreover these Hamiltonians for two dimensional Toda lattice hierarchy are also conserved quantities of the two component KP hierarchy in which that system is embedded. The one dimensional Toda lattice hierarchy is characterized by the bilinear relations, and a new version of the one dimensional Toda lattice hierarchy is constructed. Generalized Toda lattice hierarchies associated to all affine Lie algebras are presented.

Takebe, Takashi

1990-04-01

399

Understanding Evolution  

NSDL National Science Digital Library

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.

2004-02-06

400

TJNAF free electron laser damage studies  

SciTech Connect

Laser material damage experiments were conducted at the Thomas Jefferson National Accelerator Facility (TJNAF) free electron laser (FEL) user laboratorywith an average power of 100W and a power density of 104W/cm2. The FEL beam bombards the target with a steady stream of tens of millions of pulses persecond each containing 50MW of power in a short burst of ~1ps. No conventional laser combines these characteristics, and no experiments have previouslybeen done to explore the effects of the FEL pulse. The goal is to develop scaling laws to accurately describe large-scale damage from a MW FEL usingsmall-scale experiments.

Biallas, George; Neil, George; Gubeli, Joseph; Jordan, Kevin; Short, L.R.; Michelle D. Shinn; Hill, Richard; McGinnis, R.; Walker, Richard; Thomson, R.W.; Benson, Stephen; Colson, William

2001-12-01

401

Biotech Law Web Server  

NSDL National Science Digital Library

The Biotech Law home page offers legal and scientific information of interest to researchers in biotechnology/pharmaceutical science. At this time, the site provides basic articles on methods of record keeping for inventors, an explanation of the U.S. legal standard for inventorship and an overview of patent application preparation. The Biotech law home page also includes more advanced articles on intellectual property licensing, parallel importing of patented products, and the effects of electronic publication on U.S. Patent rights. In addition to a "heads up" guide to recently-issued U.S. biotech patents, the home page provides links to additional sources of information on intellectual property protection, as well as links to selected scientific resources on Internet.

Foley & Lardner.

1996-01-01

402

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.

1998-01-01

403

Harvard Law School Forum  

NSDL National Science Digital Library

Founded in 1946 by 30 law students returned from the war, the Harvard Law School Forum has remained a nonprofit, student-run organization that sponsors a variety of speakers and panel discussions featuring political, literary, and cultural luminaries from around the world. Over the years, many of these discussions have been broadcast on the radio or otherwise recorded and are now available online in their entirety. Past programs currently offered in RealPlayer format include, to name just a few, Henry Kissinger, Timothy Leary, Jimmy Hoffa, Martin Luther King, Betty Friedan, Shimon Peres, Carl Sagan, F. Lee Bailey, Mario Cuomo, Ralph Nader, Helen Thomas, Charlton Heston, and Vince McMahon. The site also features a guide to past programs (sorted by decade and some with photos or associated press clippings), a photo gallery, and information on upcoming speakers. The site is an ongoing project, and additional recordings and other materials will be added as they are prepared or become available.

404

Polish Law Governing the Press.  

National Technical Information Service (NTIS)

Uniform text of Law governing the Press of 1/1984 as amended in 1988, 1989, and 1990. The law contains provisions pertaining to rights and responsibilities of journalists; the press council; organization of press activities; rectifications and responses; ...

1992-01-01

405

Minimal Complexity Control Law Synthesis.  

National Technical Information Service (NTIS)

A paradigm for control law design for modern engineering systems is proposed: Minimize control law complexity subject to the achievement of a specified accuracy in the face of a specified level of uncertainty. Correspondingly, the overall goal is to make ...

D. S. Bernstein W. M. Haddad C. N. Nett

1989-01-01

406

A Guide to Scots Law  

NSDL National Science Digital Library

From contemporary legislation passed in London or Brussels to Roman Law to Udal (old Norse) Law, Scottish Law has many influences and inheritances. This site, created by Evi C. Athanasekou of the University of Glasgow Department of Computer Science, attempts to present "basic knowledge about the Scottish legal system that ranges from what the sources of Scots Law are to practical solutions to common everyday legal problems." At the site, users can explore the history and sources of Scots Law and learn about the current legal system structure in Scotland (which remains distinct from the English one). The Scots Law Queries section provides answers to everyday legal questions in Scotland. Additional features include a Scottish legal yellow pages section, legal terms of Scots Law, Latin words, phrases and maxims in Scots Law, and related links.

Athanasekou, Evi C.

1997-01-01

407

Henry's Law and Noisy Knuckles.  

ERIC Educational Resources Information Center

Discusses Henry's Law which describes the relationship between the pressure of gas and the concentration of that gas in a solution. Presents an application of Henry's Law to the cracking of knuckles. (CCM)

Kimbrough, Doris R.

1999-01-01

408

Inverse Square Law  

NSDL National Science Digital Library

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.

Exploratorium, The

2012-07-11

409

Biot-Savart Law  

NSDL National Science Digital Library

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.

VU Bioengineering RET Program, School of Engineering,

410

Law Library of Congress  

NSDL National Science Digital Library

The mission of the Law Library of Congress is to provide research and legal information to the U.S. Congress as well as to U.S. Federal Courts and Executive Agencies, and to offer reference services to the public. Truth be told, this is a pretty tall order, and they fulfill this objective quite admirably, and in no small part due to this fairly comprehensive and well-designed site.

411

Hyperphysics -- Coulomb's Law  

NSDL National Science Digital Library

This web page, authored by Rod Nave of Georgia State University, provides a concise, yet thorough explanation of Coulomb's Law and how it it is used to determine the electric force between charges. A Javascript calculator is available to compute forces between charges. Links are available for users to access related items or delve more deeply into electromagnetic forces. This item is part of a large hyper-linked resource that covers most of physics, with extensive use of concept maps.

Nave, Rod

2009-12-10

412

Fretting damage assessment of titanium alloys using orientation imaging microscopy  

Microsoft Academic Search

The formation of fretting damage and cracks depends strongly on the microstructure. Recent advances in orientation imaging microscopy (OIM) make it possible to obtain new assessment measurements of the near-surface layers containing fretting damage. In particular, crystallographic grain orientation, misorientations between grains, accumulation of plastic deformation, and the evolution of microstructure leading to microtexture formation and twinning can be determined

Dana R. Swalla; Richard W. Neu

2006-01-01

413

Investigation on fatigue-creep interaction damage model for solder  

Microsoft Academic Search

It is well known, reliability and workability are the more important issues in the field of chip size package (CSP). Creep and fatigue behaviors are the main loads of the solder joints, the reliability of which should take account of those two main loads. Based on the theory of continuum damage mechanics (CDM), this paper focuses on damage evolution of

Na Liu; Xiaoyan Li; Yongchang Yan

2008-01-01

414

Finite element analysis of damage accumulation for structure under impact  

Microsoft Academic Search

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

Wang Hongyan; Hao Guixiang

2011-01-01

415

First Law Model  

NSDL National Science Digital Library

The First Law model displays the dynamics of a ball subject to no net force. The initial conditions for the ball are an initial velocity in the x and y directions. The initial position of the ball can be changed by dragging it when the simulation is paused. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item. Ejs First Law model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_newton_FirstLaw.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for Newtonian mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Christian, Wolfgang

2008-06-03

416

Encyclopedia of Law and Economics  

NSDL National Science Digital Library

Conceived by the University of Ghent, Belgium, the Encyclopedia of Law and Economics Website is a broad-based collection of resources pertaining to economic and legal issues throughout the world. Showcasing a comprehensive index of searchable bibliographic resources, this site also includes abstracts of recent law and economics reviews. The hefty Law and Economics Web Resources section features working papers, bibliographies, and mailing lists. In addition, the site links to law and economics academic programs, associations, and an array of relevant Websites.

2005-12-15

417

Galactic Rotation and Natural Law  

NASA Astrophysics Data System (ADS)

There exist a number of striking empirical regularities in the kinematics of rotating galaxies. These include flat rotation curves, the Tully-Fisher relation, and a relation between gravitational force and baryonic surface density. I suggest that these may be tantamount to Natural Laws, analogous to Kepler's Laws. The physical interpretation of these Laws is fraught with peril.

McGaugh, Stacy S.

2012-05-01

418

Freedom under Law. Revised edition.  

ERIC Educational Resources Information Center

This pamphlet identifies and explains Colorado laws as they apply to juveniles and adults. The handbook was specifically developed to help teenagers know how the laws protect them and how they are expected to comply with them. Two short sections discuss the necessity of having laws and give definitions of 12 legal terms such as felony and petty…

Denver Public Schools, CO.

419

Law and the Physical Educator.  

ERIC Educational Resources Information Center

Since federal and state laws directly influence the professional activities of physical educators, it is essential to understand the implications of particular laws and regulations as well as legal processes. Some misconceptions about the law are examined, and techniques by which physical educators can affect educational policy are explored. (JN)

Jansma, Paul; French, Ron

1982-01-01

420

Immigration Law & the American Dream.  

ERIC Educational Resources Information Center

This magazine is designed to help high school teachers of civics, government, history, law, and law-related education program developers educate students about legal issues. This issue focuses on immigration law and the American Dream. It includes 11 articles: (1) "U.S. Immigration Policy and Globalization" (P. Martin; S. Martin) explains how the…

Parrini, Michelle, Ed.; Parins, Claire, Ed.; Kittlaus, Jennifer, Ed.; Bliss, Pam, Ed.

2001-01-01

421

The Death of Labor Law?  

Microsoft Academic Search

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

Cynthia L. Estlund

2006-01-01

422

Tax Breaks for Law Students.  

ERIC Educational Resources Information Center

A guide to federal income tax law as it affects law students is presented. Some costs that may constitute valuable above-the-line deductions are identified: moving expenses, educational expenses, job-seeking expenses, and income averaging. Available from Washington and Lee University School of Law, Lexington, VA 24450, $5.50 sc) (MLW)

Button, Alan L.

1981-01-01

423

The Evolution of Complex Life  

NASA Technical Reports Server (NTRS)

In considering the probabilities that intelligent life might exist elsewhere in the Universe, it is important to ask questions about the factors governing the emergence of complex living organisms in the context of evolutionary biology, planetary environments and events in space. Two important problems arise. First, what can be learned about the general laws governing the evolution of complex life anywhere in space by studying its history on the Earth? Second, how is the evolution of complex life affected by events in space? To address these problems, a series of Science Workshops on the Evolution of Complex Life was held at the Ames Research Center. Included in this paper are highlights of those workshops, with particular emphasis on the first question, namely the evolution of complex extraterrestrial life.

Billingham, John

1989-01-01

424

Characteristics of Creep Damage for 60Sn40Pb Solder Material  

Microsoft Academic Search

This paper presents a viscoplasticity model taking into account the effects of change in grain or phase size and damage on the characterization of creep damage in 60Sn-40Pb solder. Based on the theory of damage mechanics, a two-scalar damage model is developed for isotropic materials by introducing the free energy equivalence principle. The damage evolution equations are derived in terms

Y. Wei; C. L. Chow; H. E. Fang; M. K. Neilsen

1999-01-01

425

A Cosmic Coincidence: The Power-law Galaxy Correlation Function  

NASA Astrophysics Data System (ADS)

We model the evolution of galaxy clustering through cosmic time to investigate the nature of the power-law shape of ?(r), the galaxy two-point correlation function. While ?(r) at large scales is set by primordial fluctuations, departures from a power law are governed by galaxy pair counts at small scales, subject to nonlinear dynamics. We assume that galaxies reside within dark matter halos and subhalos. Therefore, the shape of the correlation function at small scales depends on the amount of halo substructure. We use a semi-analytic substructure evolution model to study subhalo populations within host halos. We find that tidal mass loss and, to a lesser extent, dynamical friction dramatically deplete the number of subhalos within larger host halos over time, resulting in a ~90% reduction by z = 0 compared to the number of distinct mergers that occur during the assembly of a host halo. We show that these nonlinear processes resulting in this depletion are essential for achieving a power law ?(r). We investigate how the shape of ?(r) depends on subhalo mass (or luminosity) and redshift. We find that ?(r) breaks from a power law at high masses, implying that only galaxies of luminosities <~ L * should exhibit power-law clustering. Moreover, we demonstrate that ?(r) evolves from being far from a power law at high redshift, toward a near power-law shape at z = 0. We argue that ?(r) will once again evolve away from a power law in the future. This is in large part caused by the evolving competition between the accretion and destruction rates of subhalos over time, which happen to strike just the right balance at z ? 0. We then investigate the conditions required for ?(r) to be a power law in a general context. We use the halo model, along with simple parameterizations of the halo occupation distribution, to probe galaxy occupation at various masses and redshifts. We show that the key ingredients determining the shape of ?(r) are the fraction of galaxies that are satellites, the relative difference in mass between the halos of isolated galaxies and halos that contain a single satellite on average, and the rareness of halos that host galaxies. These pieces are intertwined and we find no simple, universal rule for which a power law ?(r) will occur. However, we do show that the physics responsible for setting the galaxy content of halos do not care about the conditions needed to achieve a power law ?(r) and that these conditions are met only in a narrow mass and redshift range. We conclude that the power-law nature of ?(r) for L * and fainter galaxy samples at low redshift is a cosmic coincidence.

Watson, Douglas F.; Berlind, Andreas A.; Zentner, Andrew R.

2011-09-01

426

Kinetics of wealth and the Pareto law  

NASA Astrophysics Data System (ADS)

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.

Boghosian, Bruce M.

2014-04-01

427

Punctuated equilibrium in software evolution  

NASA Astrophysics Data System (ADS)

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.

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

2004-12-01

428

Punctuated equilibrium in software evolution.  

PubMed

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. PMID:15697556

Gorshenev, A A; Pis'mak, Yu M

2004-12-01

429

A high accuracy femto-/picosecond laser damage test facility dedicated to the study of optical thin films  

NASA Astrophysics Data System (ADS)

A laser damage test facility delivering pulses from 100 fs to 3 ps and designed to operate at 1030 nm is presented. The different details of its implementation and performances are given. The originality of this system relies the online damage detection system based on Nomarski microscopy and the use of a non-conventional energy detection method based on the utilization of a cooled CCD that offers the possibility to obtain the laser induced damage threshold (LIDT) with high accuracy. Applications of this instrument to study thin films under laser irradiation are presented. Particularly the deterministic behavior of the sub-picosecond damage is investigated in the case of fused silica and oxide films. It is demonstrated that the transition of 0-1 damage probability is very sharp and the LIDT is perfectly deterministic at few hundreds of femtoseconds. The damage process in dielectric materials being the results of electronic processes, specific information such as the material bandgap is needed for the interpretation of results and applications of scaling laws. A review of the different approaches for the estimation of the absorption gap of optical dielectric coatings is conducted and the results given by the different methods are compared and discussed. The LIDT and gap of several oxide materials are then measured with the presented instrument: Al2O3, Nb2O5, HfO2, SiO2, Ta2O5, and ZrO2. The obtained relation between the LIDT and gap at 1030 nm confirms the linear evolution of the threshold with the bandgap that exists at 800 nm, and our work expands the number of tested materials.

Mangote, B.; Gallais, L.; Zerrad, M.; Lemarchand, F.; Gao, L. H.; Commandré, M.; Lequime, M.

2012-01-01

430

Plate tectonics, damage and inheritance  

NASA Astrophysics Data System (ADS)

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.

Bercovici, David; Ricard, Yanick

2014-04-01

431

Genetic technologies and courts of law.  

PubMed

Human genetic testing, and its next logical technological plateau, gene therapy, are largely unregulated in the United States and much of the world. Since the basic science and some of the technological know-how related to such tests and therapeutic regimes cross national boundaries, the disputes that follow in the wake of popular response to such technological advances could arise in virtually any court of the world. For much of the post-industrial world, this pits the unfettered processes of medical decision-making against standards of the rule of law enforced by independent courts of law. For a substantial portion of the developing world, courts are not independent and the rule of law is precariously standardized. There the proponents of unbounded genetic test development and experimentation have greatest opportunities for mischief that can create civil, criminal and military strife. In this paper we propose and discuss methods to forecast case scenarios. We will emphasize the globalization of civil and criminal conflicts that may be spurred by the use of genetic testing. Extra-judicial dispute resolution is likely to fail in the case of genetic tests. We finally propose an international means of judicial discourse that has potential to bring objectivity and even-handedness to the just resolution of issues spurred by genetic testing and engineered evolution. PMID:11881639

Zweig, F M; Davis, A M

2000-01-01

432

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.

433

Confidentiality and the law.  

PubMed Central

Codes of medical ethics issued by professional organizations typically contain statements affirming the importance of confidentiality between patients and health-care practitioners. Seldom, however, is the confidentiality obligation depicted as absolute. Instead, exceptions are noted, the most common of which is that health-care professionals are justified in breaching the confidence of a patient if required by law to do so. Reasons that might be given to support this exception are critically discussed in this paper. The conclusion argued for is that this is not a legitimate exception to the confidentiality rule.

McConnell, T

1994-01-01

434

Deriving Darcy's Law  

NSDL National Science Digital Library

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.

Salvage, Karen

435

Punctuated Equilibrium in Software Evolution  

Microsoft Academic Search

The approach based on paradigm of self-organized criticality proposed for experimental investi- gation and theoretical modelling of software evolution. The dynamics of modifications studied for three free, open source programs Mozilla, Free-BSD and Emacs using the data from version control systems. Scaling laws typical for the self-organization criticality found. The model of software evo- lution presenting the natural selection principle

A. A. Gorshenev; Yu. M. Pis'mak

2003-01-01

436

Towards energetic consistent transition from damage to fracture  

NASA Astrophysics Data System (ADS)

From the theoretical point of view, an energetically transition from damage to fracture should occur for totally damaged material. Nevertheless, in terms of numerical simulation, this condition leads to a singularity in the constitutive equations, when the Lemaitre model for ductile damage is used to describe material behavior. In this work, a cohesive law is inserted in a previous developed model for the transition of damage to fracture using XFEM in order to overcome this limitation. An exponential type of cohesive law is assumed, but its defining parameters are not considered to be a characteristic of the material but are rather fitted to fulfill energetic requirements. The efficiency of the proposed approach is tested in various numerical examples.

Seabra, Mariana R. R.; Cesar de Sa, José M. A.

2013-05-01

437

Plasticity-damage couplings in titanium  

NASA Astrophysics Data System (ADS)

At room temperature, titanium materials display deformation and failure properties that are quite different from that of typical materials with cubic crystalline structure (aluminium, steels, etc). Rolled or extruded products exhibit a strong anisotropy and very pronounced difference in yielding and work-hardening evolution between tension and compression loadings. In this paper, a macroscopic elastic/plastic model that accounts for the key features of the plastic deformation of Ti, in particular the distortion of the yield surface induced by texture evolution is presented. Comparison with data demonstrates that the model predicts with accuracy the plastic response for a variety of loading conditions. Furthermore, it is shown that the model can be extended such as to incorporate damage. In contrast to existing approaches, the plasticity-damage couplings are deduced and not postulated. Hence, all material parameters have a clear physical significance, being related to plastic properties that can be determined from few simple mechanical tests. The new model predicts that in titanium materials damage accumulation is strongly influenced by the anisotropy and asymmetry in plastic flow. Moreover, it is shown that under uniaxial tension, the porosity evolution should be much slower than in materials with plastic flow obeying the classical von Mises criterion, and that the succession of damage events leading to failure should also be markedly different.

Cazacu, Oana; Baudard, Benoit Revil

2013-12-01

438

China's Juvenile Delinquency Prevention Law: the law and the philosophy.  

PubMed

The present study introduces and discusses the Juvenile Delinquency Prevention Law of the People's Republic of China. The law was promulgated in the context of Chinese socioeconomic reforms and legal reforms in response to the rising delinquency since the early 1980s. The study explains the social and political background of the law with respect to the patterns of delinquency in China. The law has several main features that reflect the Chinese philosophical underpinnings of crime prevention and control, and the study discusses the connection between the law and the traditional Chinese philosophy and thinking. Finally, the study discusses the challenges to the enforcement of the law in Chinese society, which has lacked a legal tradition in its history. PMID:17600300

Lening Zhang; Jianhong Liu

2007-10-01

439

Evolution Lessons  

NSDL National Science Digital Library

This collection of lessons from the Evolution and the Nature of Science Institute (ENSI) focus on evolution. Each title is an active link to the named activity. The site also contains links to synopses for all of the lessons and a statement on the appropriate grade level for the lessons.

440

FTS evolution  

NASA Technical Reports Server (NTRS)

Viewgraphs on flight telerobotic servicer evolution are presented. Topics covered include: paths for FTS evolution; frequently performed actions; primary task states; EPS radiator panel installation; generic task definitions; path planning; non-contact alignment; contact planning and control; and human operator interface.

Provost, David E.

1990-01-01

441

Stellar Evolution  

NSDL National Science Digital Library

This site discusses hydrostatic balance, radiation pressure, and gravity and how these things affect the evolution of a star based on its mass. There are three sections that talk about the mass criteria, lifetime, and evolution on the H-R diagram of red dwarfs, mid mass stars, and high mass stars. This site ends with a short quiz.

Miller, Kristen; Miller, Scott

2010-05-25

442

Stellar Evolution  

NSDL National Science Digital Library

This Chandra X-Ray Observatory page links to several activities and articles on stellar evolution. It includes an interactive Flash activity featuring simulations of different-mass stars evolving and a detailed "story" of stellar evolution for the interested reader, available in PDF and HTML formats.

2010-05-28

443

A scaling law of radial gas distribution in disk galaxies  

NASA Technical Reports Server (NTRS)

Based on the idea that local conditions within a galactic disk largely determine the region's evolution time scale, researchers built a theoretical model to take into account molecular cloud and star formations in the disk evolution process. Despite some variations that may be caused by spiral arms and central bulge masses, they found that many late-type galaxies show consistency with the model in their radial atomic and molecular gas profiles. In particular, researchers propose that a scaling law be used to generalize the gas distribution characteristics. This scaling law may be useful in helping to understand the observed gas contents in many galaxies. Their model assumes an exponential mass distribution with disk radius. Most of the mass are in atomic gas state at the beginning of the evolution. Molecular clouds form through a modified Schmidt Law which takes into account gravitational instabilities in a possible three-phase structure of diffuse interstellar medium (McKee and Ostriker, 1977; Balbus and Cowie, 1985); whereas star formation proceeds presumably unaffected by the environmental conditions outside of molecular clouds (Young, 1987). In such a model both atomic and molecular gas profiles in a typical galactic disk (as a result of the evolution) can be fitted simultaneously by adjusting the efficiency constants. Galaxies of different sizes and masses, on the other hand, can be compared with the model by simply scaling their characteristic length scales and shifting their radial ranges to match the assumed disk total mass profile sigma tot(r).

Wang, Zhong

1990-01-01

444

Indentation Damage in Ceramics.  

National Technical Information Service (NTIS)

The basic processes of indentation damage in brittle ceramics have been studied. Attention has focused on the roles of material crystallography and microstructure in determining the nature of the damage pattern. Microscopy techniques, particularly transmi...

B. R. Lawn B. J. Hockey

1987-01-01

445

Femoral nerve damage (image)  

MedlinePLUS

The femoral nerve is located in the leg and supplies the muscles that assist help straighten the leg. It supplies sensation ... leg. One risk of damage to the femoral nerve is pelvic fracture. Symptoms of femoral nerve damage ...

446

Diabetes and nerve damage  

MedlinePLUS

Nerve damage that occurs in people with diabetes is called diabetic neuropathy. This condition is a complicaiton ... In people with diabetes, the body's nerves can be damaged by ... level . This condition is more likely when blood sugar level ...

447

hr-law: Human Rights Law Mailing List  

NSDL National Science Digital Library

hr-law is a mailing list for law students studying international human rights or humanitarian law, or who are just interested in the subject. The purpose of the list is to provide a forum where people can share information, experiences and ideas. Some of the appropriate topics for this list include: information on how to do research in the human rights area, and sharing of hints; exchanging help on papers or research projects; discussion of topics related to human rights law; and sharing information on employment, internship and volunteer opportunities.

448

Relations between Continuous Versions of Bibliometric Laws.  

ERIC Educational Resources Information Center

Demonstrates how the addition of a third "hidden" variable to the two parameters in Lotka's law makes this law equivalent, in a strictly logical sense, with Mandelbrot's law. Similarly, Lotka's inverse square law is made equivalent with Leimkuhler's law. It is also shown how Pareto's law fits into this framework. (29 references) (Author/CLB)

Rousseau, Ronald

1990-01-01

449

The law of mortality revisited: interspecies comparisons of mortality.  

PubMed

In 1825 the British actuary Benjamin Gompertz believed he had discovered a consistency in the timing of death in people that was so important that he labelled his observation a 'law of mortality'. To Gompertz, this 'law' was equivalent in importance to Newton's law of gravity because he believed it would be observed in all living things. Gompertz's quest for the 'law' eventually failed, as did similar efforts by other scientists in the 19th and most of the 20th century. However, the search for the law of mortality was successfully resolved in 1996 when my colleagues and I discovered that the only way to 'see' Gompertz's law expressed as common age patterns of death across species was to partition total mortality into its intrinsic and extrinsic components, and examine mortality schedules on a uniform time scale. Scientists had been unable to reveal the law of mortality in the past not only because they could not partition total mortality, but also because of the previous anthropocentric perspective that forced some scientists to view duration of life along a single time scale - one based on human measurements of chronological time. The law of mortality is relevant today not only because it links the epidemiology of disease, ageing and death across species, but because it creates a window into the future for those who study disease epidemiology in animals that now live long enough in protected environments to experience the biological consequences of ageing. In this paper I summarize the historical search for the law of mortality, explain why the solution could only be found by linking two seemingly unconnected scientific disciplines (evolution biology and actuarial/demographics), explain why age patterns of disease and death in humans may be used to understand and predict disease epidemiology in other species, and describe how a new scientific discipline has arisen in the modern era as a result of this research. PMID:19954793

Olshansky, S J

2010-01-01

450

High-density polyethylene damage at extreme tensile conditions  

NASA Astrophysics Data System (ADS)

In-situ and postmortem 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 (>105 s?1) by firing projectiles through a conical die. Postmortem sectioning elucidates a mechanism of internal damage inception and progression. X-ray computed tomography corroborates shear damage with cracks nearly aligned with the extrusion axis but separated by unfailed internal bridges of material. In-situ measurements of damage are made with the impact system for ultrafast synchrotron experiments (IMPULSE) using the advanced imaging X-ray methods available at the Advanced Photon Source. Multiple frame phase-contrast imaging (PCI) elucidates the evolution of damage features in HDPE during Dyn-Ten-Ext loading that is observed in postmortem sectioning and X-ray tomography.

Brown, E. N.; Furmanski, J.; Ramos, K. J.; Dattelbaum, D. M.; Jensen, B. J.; Iverson, A. J.; Carlson, C. A.; Fezzaa, K.; Gray, G. T., III; Patterson, B. M.; Trujillo, C. P.; Martinez, D. T.; Pierce, T. H.

2014-05-01

451

Damage control resuscitation: history, theory and technique  

PubMed Central

Damage control resuscitation (DCR) represents the natural evolution of the initial concept of damage control surgery. It currently includes early blood product transfusion, immediate arrest and/or temporization of ongoing hemorrhage (i.e., temporary intravascular shunts and/or balloon tamponade) as well as restoration of blood volume and physiologic/hematologic stability. As a result, DCR addresses the early coagulopathy of trauma, avoids massive crystalloid resuscitation and leaves the peritoneal cavity open when a patient approaches physiologic exhaustion without improvement. This concept also applies to severe injuries within anatomical transition zones as well as extremities. This review will discuss each of these concepts in detail.

Ball, Chad G.

2014-01-01

452

Algorithms for gradient damage models based on a semi-smooth Newton method  

Microsoft Academic Search

In this paper two different algorithms are applied to a model of brittle damage including the gradient of the damage variable. Both algorithms are based on a modified Newton method. In the first algorithm the Newton method is applied directly to the whole system of equations, while in the second algorithm, the equilibrium equations and the damage evolution problem are

Peter J. Ireman

2005-01-01

453

Thermodynamic modeling of creep damage in materials with different properties in tension and compression  

Microsoft Academic Search

A constitutive model is developed to describe the creep response of polycrystalline metals and alloys with different behavior in tension and compression. A second-order damage tensor is introduced in order to describe the creep damage under nonproportional loading in nonisothermal processes. The thermodynamic formulation of the creep equation and the damage evolution equation is used to study the creep behavior

George Z. Voyiadjis; Alexander Zolochevsky

2000-01-01

454

A constitutive theory for creep behavior of initially isotropic materials sustaining unilateral damage  

Microsoft Academic Search

The goal of the present work is to modify structure of the creep constitutive equations existing in the literature, and simultaneously to incorporate both damage induced anisotropy and unilateral damage into the constitutive model. The proposed nonlinear-tensor constitutive equation for creep together with the damage evolution equation take into account the secondary and tertiary creep of the initially isotropic materials.

J. Betten; A. Sklepus; A. Zolochevsky

2003-01-01

455

Creep failure model of a tempered martensitic stainless steel integrating multiple deformation and damage mechanisms  

Microsoft Academic Search

A new model considering both deformation and damage evolution under multiple viscoplastic mechanisms is used to represent high temperature creep deformation and damage of a martensitic stainless steel in a wide range of load levels. First, an experimental database is built to characterise both creep flow and damage behaviour using tests on various kinds of specimens. The parameters of the

V. Gaffard; J. Besson; A. F. Gourgues-Lorenzon

2005-01-01

456

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

Microsoft Academic Search

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

Ridha Hambli

2001-01-01

457

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

Microsoft Academic Search

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

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

2011-01-01

458

Anisotropic Damage Analysis of HY100 Steel Under Quasistatic Loading Conditions  

SciTech Connect

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.

Los Alamos National Laboratory

2001-01-01

459

Should assisted dying be lawful?  

PubMed

Calls for a change in the law to allow strictly controlled forms of assisted dying in the UK have resurfaced following a much-publicised storyline on the subject on the TV soap opera Coronation Street and the impending debate on Lord Falconer's Assisted Dying Bill in the House of Lords. This article reviews the current stance of the law on euthanasia and assisted dying and considers Lord Falconer's attempts to reform the law through the Assisted Dying Bill. PMID:24514111

Griffith, Richard

2014-02-01

460

American Society of International Law  

NSDL National Science Digital Library

The American Society of International Law (ASIL) aims to educate and engage the public in issues concerning international law. The society's extensive Website contains a wealth of information, including several online publications, bibliographies, the ASIL Guide to Electronic Resources for International Law, and ASILEX, a searchable database of ASIL publications from 1964 to the present. In addition, the site provides a detailed introduction and history of the society, profiles its membership, and maintains a calendar of important events and activities.

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