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Sample records for damage evolution law

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  2. Evolution of the Second Law of Thermodynamics

    ERIC Educational Resources Information Center

    Raman, V. V.

    1970-01-01

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

  3. Radiation damage evolution in ceramics

    SciTech Connect

    Devanathan, Ramaswami

    2009-09-15

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

  4. Complexity, organization, evolution, and constructal law

    NASA Astrophysics Data System (ADS)

    Bejan, A.; Errera, M. R.

    2016-02-01

    Physics is concise, simple, unambiguous, and constantly improving. Yet, confusion reigns in the field especially with respect to complexity and the second law of thermodynamics. In this paper, we step back and take a look at these notions—their meaning and definition—on the background provided by nature and thermodynamics. We review the central concepts and words that underpin the physics of evolutionary design today: information, knowledge, evolution, change, arrow of time, pattern, organization, drawings, complexity, fractal dimension, object, icon, model, empiricism, theory, disorder, second law, the "any" system in thermodynamics, morphing freely, and the constructal law. We show, for example, that information is not knowledge, fractal dimension is not a measure of complexity, and pattern is not a live flow architecture. Drawings, as physical means to facilitate the flow of knowledge, are subject to the natural tendency toward design evolution. Complexity, organization, and evolution in nature are most powerful and useful when pursued as a discipline, with precise terms, rules, and principles.

  5. Stochastic damage evolution in textile laminates

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  6. Optimization of control laws for damage detection in smart structures

    NASA Astrophysics Data System (ADS)

    Ray, Laura R.; Marini, Solomon

    2000-06-01

    A prevalent method of damage detection is based on identifying changes in modal characteristics due to damage induced variations in stiffness or mass along a structure. It is known that modal frequencies can be insensitive to damage, and the open-loop sensitivity itself depends on modal properties and damage location. Here, we develop methods of designing control laws that enhance the sensitivity of modal characteristics to damage. Sensitivity enhancing control exploits the relationship between control gains and closed-loop dynamics in order to increase the observability of damage. The design methods are based on optimization of cost functions that involve the dependence of classic measures of sensitivity on design variables, which include placement of sensors and actuators and state feedback control gains. Due to the size of the design space and the unknown nature of the cost surface, genetic algorithms are used to find control laws that maximize sensitivity to specific damage types subject to control effort and stability constraints. Optimized control laws designed for sensitivity enhancement of stiffness damage in a cantilevered beam are demonstrated by numerical simulation.

  7. Damages for pain and suffering in tort law.

    PubMed

    Mendelson, Danuta

    2008-05-01

    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.

  8. Brittleness Effect on Rock Fatigue Damage Evolution

    NASA Astrophysics Data System (ADS)

    Nejati, Hamid Reza; Ghazvinian, Abdolhadi

    2014-09-01

    The damage evolution mechanism of rocks is one of the most important aspects in studying of rock fatigue behavior. Fatigue damage evolution of three rock types (onyx marble, sandstone and soft limestone) with different brittleness were considered in the present study. Intensive experimental tests were conducted on the chosen rock samples and acoustic emission (AE) sensors were used in some of them to monitor the fracturing process. Experimental tests indicated that brittleness strongly influences damage evolution of rocks in the course of static and dynamic loading. AE monitoring revealed that micro-crack density induced by the applied loads during different stages of the failure processes increases as rock brittleness increases. Also, results of fatigue tests on the three rock types indicated that the rock with the most induced micro-cracks during loading cycles has the least fatigue life. Furthermore, the condition of failure surfaces of the studied rocks samples, subjected to dynamic and static loading, were evaluated and it was concluded that the roughness of failure surfaces is influenced by loading types and rock brittleness. Dynamic failure surfaces were rougher than static ones and low brittle rock demonstrate a smoother failure surface compared to high brittle rock.

  9. Are There Laws of Genome Evolution?

    PubMed Central

    Koonin, Eugene V.

    2011-01-01

    Research in quantitative evolutionary genomics and systems biology led to the discovery of several universal regularities connecting genomic and molecular phenomic variables. These universals include the log-normal distribution of the evolutionary rates of orthologous genes; the power law–like distributions of paralogous family size and node degree in various biological networks; the negative correlation between a gene's sequence evolution rate and expression level; and differential scaling of functional classes of genes with genome size. The universals of genome evolution can be accounted for by simple mathematical models similar to those used in statistical physics, such as the birth-death-innovation model. These models do not explicitly incorporate selection; therefore, the observed universal regularities do not appear to be shaped by selection but rather are emergent properties of gene ensembles. Although a complete physical theory of evolutionary biology is inconceivable, the universals of genome evolution might qualify as “laws of evolutionary genomics” in the same sense “law” is understood in modern physics. PMID:21901087

  10. In-situ damage evolution and micro/macro transition for laminated composites

    NASA Astrophysics Data System (ADS)

    Fan, Jinghong; Zhang, Junqian

    In this paper, a theoretical formulation for the development of matrix cracking damage in composite laminates is presented. To describe the constraint effects on any layer k, an in situ damage effective function, Lambda(k)(ij), is introduced. An equivalent constraint model and a micro/macroscopic damage analysis are then developed to express Lambda(k)(ij) explicitly in terms of constraint stiffness and thickness ratio as well as a damage state variable, D(k). The reduction of E, G and nu in the in situ damage state and a constrained damage evolution law incorporating residual curing strain are then derived through Lambda(k)(ij) and d Lambda(k)(ij)/d D(k), respectively. A series of experimental results are correlated and some phenomena, such as the effects of the lamina thickness on damage initiation, damage evolution, and energy dissipation, are predicted and explained.

  11. The evolution of law in biopreparedness.

    PubMed

    Hodge, James G

    2012-03-01

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

  12. The constructal law of design and evolution in nature.

    PubMed

    Bejan, Adrian; Lorente, Sylvie

    2010-05-12

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

  13. The constructal law and the evolution of design in nature.

    PubMed

    Bejan, Adrian; Lorente, Sylvie

    2011-10-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Luo, Liao-Fu

    2009-06-01

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

  15. The constructal law of design and evolution in nature

    PubMed Central

    Bejan, Adrian; Lorente, Sylvie

    2010-01-01

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

  16. Evolution of the violin: The law of effect in action.

    PubMed

    Wasserman, Edward A; Cullen, Patrick

    2016-01-01

    As is true for most other human inventions, the origin of the violin is unknown. What is known is that this popular and versatile instrument has notably changed over the course of several hundred years. At issue is whether those evolutionary changes in the construction of the violin are the result of premeditated, intelligent design or whether they arose through a trial-and-error process. Recent scientific evidence favors the latter account. Our perspective piece puts these recent empirical findings into a comprehensive selectionist framework. According to this view, the many things we do and make--like violins--arise from a process of variation and selection which accords with the law of effect. Contrary to popular opinion, there is neither mystique nor romance in this process; it is as fundamental and ubiquitous as the law of natural selection. As with the law of natural selection in the evolution of organisms, there is staunch resistance to the role of the law of effect in the evolution of human inventions. We conclude our piece by considering several objections to our perspective.

  17. Permeability of WIPP Salt During Damage Evolution and Healing

    SciTech Connect

    BODNER,SOL R.; CHAN,KWAI S.; MUNSON,DARRELL E.

    1999-12-03

    The presence of damage in the form of microcracks can increase the permeability of salt. In this paper, an analytical formulation of the permeability of damaged rock salt is presented for both initially intact and porous conditions. The analysis shows that permeability is related to the connected (i.e., gas accessible) volumetric strain and porosity according to two different power-laws, which may be summed to give the overall behavior of a porous salt with damage. This relationship was incorporated into a constitutive model, known as the Multimechanism Deformation Coupled Fracture (MDCF) model, which has been formulated to describe the inelastic flow behavior of rock salt due to coupled creep, damage, and healing. The extended model was used to calculate the permeability of rock salt from the Waste Isolation Pilot Plant (WIPP) site under conditions where damage evolved with stress over a time period. Permeability changes resulting from both damage development under deviatoric stresses and damage healing under hydrostatic pressures were considered. The calculated results were compared against experimental data from the literature, which indicated that permeability in damaged intact WIPP salt depends on the magnitude of the gas accessible volumetric strain and not on the total volumetric strain. Consequently, the permeability of WIPP salt is significantly affected by the kinetics of crack closure, but shows little dependence on the kinetics of crack removal by sintering.

  18. Law & psychiatry: the evolution of laws regulating psychiatric commitment in France.

    PubMed

    Gourevitch, Raphaël; Brichant-Petitjean, Clara; Crocq, Marc-Antoine; Petitjean, François

    2013-07-01

    This column reviews the evolution of French laws governing psychiatric commitment, culminating in the July 2011 Act, which was opposed by most professional organizations. The 2011 Act has maintained the two traditional French approaches to involuntary treatment: at the request of a third person and upon a decision by a prefect representing the government. However, the 2011 Act introduced major innovations into French practices: systematic review by a judge, a 72-hour observation period, and the possibility of compulsory community treatment.

  19. Progressive damage state evolution and quantification in composites

    NASA Astrophysics Data System (ADS)

    Patra, Subir; Banerjee, Sourav

    2016-04-01

    fatigue cycles was performed to extract the useful information about the damage state. This study has potential to investigate progressive damage evolution and to quantify at different fatigue cycles.

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

    PubMed Central

    Collin, Rachel; Cipriani, Roberto

    2003-01-01

    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). PMID:14728776

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

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

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

  2. Fault Wear by Damage Evolution During Steady-State Slip

    NASA Astrophysics Data System (ADS)

    Lyakhovsky, Vladimir; Sagy, Amir; Boneh, Yuval; Reches, Ze'ev

    2014-11-01

    Slip along faults generates wear products such as gouge layers and cataclasite zones that range in thickness from sub-millimeter to tens of meters. The properties of these zones apparently control fault strength and slip stability. Here we present a new model of wear in a three-body configuration that utilizes the damage rheology approach and considers the process as a microfracturing or damage front propagating from the gouge zone into the solid rock. The derivations for steady-state conditions lead to a scaling relation for the damage front velocity considered as the wear-rate. The model predicts that the wear-rate is a function of the shear-stress and may vanish when the shear-stress drops below the microfracturing strength of the fault host rock. The simulated results successfully fit the measured friction and wear during shear experiments along faults made of carbonate and tonalite. The model is also valid for relatively large confining pressures, small damage-induced change of the bulk modulus and significant degradation of the shear modulus, which are assumed for seismogenic zones of earthquake faults. The presented formulation indicates that wear dynamics in brittle materials in general and in natural faults in particular can be understood by the concept of a "propagating damage front" and the evolution of a third-body layer.

  3. [Safety and accuracy of surgical procedures: case law evolution].

    PubMed

    Rougé-Maillart, C; Gaudin, A; Lermite, E; Arnaud, J-P; Penneau, M

    2008-01-01

    Surgeons, like other doctors, practice their profession within a framework of contractual liability defined by statute in 1936. This established that the doctor was subject to a contractual obligation to provide appropriate and diligent care. Care and technical acts should conform to those which would have been provided by a prudent doctor within the standards of knowledge and practice of his field; care which deviates from this standard would be considered medical error or fault. This standard of care is referred to as "sound professional conduct". However, while not calling this basic principle into question, civil jurisdictions have progressively held surgeons liable whenever injury has occurred following surgical acts, without considering whether care deviates from sound professional conduct. Since 2000, judges have begun to attribute a requirement for absolute safety of results in cases where the surgeon had injured an organ unrelated to the planned operation. However it seems that the rare judgments given on this topic in the last 2-3 years have become less frequent. The creation of a compensation regime for medical accidents, via the law dated March 4, 2002, has contributed to this evolution. It is to be hoped that the flaws described in this system do not encourage jurisdictions to reconsider previous case law decisions.

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

    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.

  5. Empirical laws of survival and evolution: Their universality and implications

    PubMed Central

    Azbel', Mark Ya.

    1999-01-01

    Presented analysis of human and fly life tables proves that with the specified accuracy their entire survival and mortality curves are uniquely determined by a single point (e.g., by the birth mortality q0), according to the law, which is universal for species as remote as humans and flies. Mortality at any age decreases with the birth mortality q0. According to life tables, in the narrow vicinity of a certain q0 value (which is the same for all animals of a given species, independent of their living conditions), the curves change very rapidly and nearly simultaneously for an entire population of different ages. The change is the largest in old age. Because probability to survive to the mean reproductive age quantifies biological fitness and evolution, its universal rapid change with q0 (which changes with living conditions) manifests a new kind of an evolutionary spurt of an entire population. Agreement between theoretical and life table data is explicitly seen in the figures. Analysis of the data on basic metabolism reduces it to the maximal mean lifespan (for animals from invertebrates to mammals), or to the maximal mean fission time (for bacteria), and universally scales them with the total number of body atoms only. Phenomenological origin of this unification and universality of metabolism, survival, and evolution is suggested. Their implications and challenges are discussed. PMID:10611390

  6. Chromosome damage evolution after low and high LET irradiation

    NASA Astrophysics Data System (ADS)

    Andreev, Sergey; Eidelman, Yuri

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

  7. Evolution of the passive film on mechanically damaged nitinol.

    PubMed

    Schroeder, Valeska

    2009-07-01

    The corrosion behavior of Nitinol-based medical implants is critical to their success in vivo. Contemporary Nitinol-based medical implants are typically chemically passivated or electrochemically polished to form a protective passive film. However, mechanically formed surfaces caused by handling damage, fretting, or fatigue fracture may also be present on a device in vivo. In this study, mechanically polished surfaces are used to simulate mechanically damaged surfaces such that analytical techniques, including electrochemical impedance spectroscopy, open circuit potential monitoring, X-ray photoelectron spectroscopy (XPS), and Mott-Schottky analysis may be used to monitor the evolution of the passive film on mechanically damaged Nitinol. These mechanically polished Nitinol surfaces are compared with chemically passivated and electrochemically polished Nitinol surfaces and mechanically polished titanium surfaces in phosphate buffered saline solution. The mechanically polished Nitinol exhibits lower impedance at low frequencies, empirically modeled to a thinner film with lower film resistance than chemically passivated and electrochemically polished Nitinol and mechanically polished titanium. Moreover, the passive film on mechanically polished Nitinol continues to develop over time, increasing in its thickness and film resistance. This characterization demonstrates that mechanically formed surfaces may be initially less protective than chemically passivated and electrochemically polished Nitinol surfaces, but continue to become thicker and more resistant to electrochemical reactions with exposure to saline solution.

  8. The Evolution of Health Care Advance Planning Law and Policy

    PubMed Central

    Sabatino, Charles P

    2010-01-01

    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. PMID:20579283

  9. Beyond Rio? The Evolution of International Environmental Law.

    ERIC Educational Resources Information Center

    Brunnee, Jutta

    1993-01-01

    Discusses the expansion and innovation in the use of international environmental law mechanisms to address the problems of global environmental protection. Presents initiatives involving customary international law, forms of international agreements, nonbinding "soft law," and an example involving Canada's biodiversity commitments. (MDH)

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

    SciTech Connect

    Gray, George T., III; Livescu, Veronica; Cerreta, Ellen K

    2010-03-18

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

  11. Scale Invariance in Landscape Evolution Models Using Stream Power Laws

    NASA Astrophysics Data System (ADS)

    Kwang, J. S.; Parker, G.

    2014-12-01

    Landscape evolution models (LEM) commonly utilize stream power laws to simulate river incision with formulations such as E = KAmSn, where E is a vertical incision rate [L/T], K is an erodibility constant [L1-2m/T], A is an upstream drainage area [L2], S is a local channel gradient [-], and m and n are positive exponents that describe the basin hydrology. In our reduced complexity model, the landscape approached equilibrium by balancing an incision rate with a constant, uniform, vertical rock uplift rate at every location in the landscape. From our simulations, for a combination of m and n, the landscape exhibited scale invariance. That is, regardless of the size and scale of the basin, the relief and vertical structure of the landscape remained constant. Therefore, the relief and elevation profile of the landscape at equilibrium were only dependent on the coefficients for erodibility and uplift and an equation that described how upstream area, A, increased as the length of a stream increased. In our analytical 1D models, we utilized two equations that described upslope area, (a) A = Bl, where B is the profile width [L], and l is the stream length from the ridge [L] and (b) A = Clh, Hack's Law, where C is a constant [L2-h] and h is a positive exponent. With these equations, (a) m = n and (b) hm = n resulted in scale invariance. In our numerical 2D models, the relationship between A and l was inherent in the actual structure of the drainage network. From our numerical 2D results, scale invariance occurred when 2m = n. Additionally, using reasonable values from the literature for exponents, n, m and h, resulted in singularities at the ridges in the landscape, which caused truncation error. In consequence, the elevation of the ridge increased as the number of grid cells in the domain increased in the numerical model, and the model was unable to converge. These singularities at the ridges appeared when (a) m ≥ n and (b) hm ≥ n in the analytical model and 2m ≥ n in

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

    PubMed

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

    2014-12-01

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

  13. Constructal law of design and evolution: Physics, biology, technology, and society

    NASA Astrophysics Data System (ADS)

    Bejan, Adrian; Lorente, Sylvie

    2013-04-01

    This is a review of the theoretical and applied progress made based on the Constructal law of design and evolution in nature, with emphasis on the last decade. The Constructal law is the law of physics that accounts for the natural tendency of all flow systems (animate and inanimate) to change into configurations that offer progressively greater flow access over time. The progress made with the Constructal law covers the broadest range of science, from heat and fluid flow and geophysics, to animal design, technology evolution, and social organization (economics, government). This review presents the state of this fast growing field, and draws attention to newly opened directions for original research. The Constructal law places the concepts of life, design, and evolution in physics.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    Ground-penetrating radar (GPR) is being increasingly used for pavements maintenance due to the wide range of applications spanning from physical to geometrical inspections, thereby allowing for a reliable diagnosis of the main causes of road structural damages. In this work, an off-ground GPR system was used to investigate a large-scale rural road network. Two sets of surveys were carried out in different time periods, with the main goals to i) localize the most critical sections; ii) monitor the evolution of previous damages and localize newborn deep faults, although not revealed at the pavement surface level; iii) analyze the causes of both evolution and emergence of faults by considering environmental and human factors. A 1-GHz GPR air-launched antenna was linked to an instrumented van for collecting data at traffic speed. Other support techniques (e.g. GPS data logger, odometer, HD video camera) were used for cross-checking,. Such centre frequency of investigation along with a 25-ns time window allow for a signal penetration of 900 mm, consistent with the deepest layer interfaces. The bottom of the array was 400 mm over the surface, with a minimum distance of 1200 mm from the van body. Scan length of maximum 10 km were provided for avoiding heavy computational loads. The rural road network was located in the District of Rieti, 100 km north from Rome, Italy, and mostly develops in a hilly and mountainous landscape. In most of the investigated roads, the carriageway consists in two lanes of 3.75 meters wide and two shoulders of 0.50 meters wide. A typical road section includes a HMA layer (65 mm average thickness), a base layer (100 mm average thickness), and a subbase layer (300 mm average thickness), as described by pavement design charts. The first set of surveys was carried out in two days at the beginning of spring in moderately dry conditions. Overall, 320-km-long inspections were performed in both travel directions, thereby showing a productivity of

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

    PubMed

    Jones, Owen D

    2004-11-29

    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.

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

    PubMed Central

    Jones, Owen D

    2004-01-01

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

  17. A biophysical model of cell evolution after cytotoxic treatments: Damage, repair and cell response.

    PubMed

    Tomezak, M; Abbadie, C; Lartigau, E; Cleri, F

    2016-01-21

    We present a theoretical agent-based model of cell evolution under the action of cytotoxic treatments, such as radiotherapy or chemotherapy. The major features of cell cycle and proliferation, cell damage and repair, and chemical diffusion are included. Cell evolution is based on a discrete Markov chain, with cells stepping along a sequence of discrete internal states from 'normal' to 'inactive'. Probabilistic laws are introduced for each type of event a cell can undergo during its life: duplication, arrest, senescence, damage, reparation, or death. We adjust the model parameters on a series of cell irradiation experiments, carried out in a clinical LINAC, in which the damage and repair kinetics of single- and double-strand breaks are followed. Two showcase applications of the model are then presented. In the first one, we reconstruct the cell survival curves from a number of published low- and high-dose irradiation experiments. We reobtain a very good description of the data without assuming the well-known linear-quadratic model, but instead including a variable DSB repair probability. The repair capability of the model spontaneously saturates to an exponential decay at increasingly high doses. As a second test, we attempt to simulate the two extreme possibilities of the so-called 'bystander' effect in radiotherapy: the 'local' effect versus a 'global' effect, respectively activated by the short-range or long-range diffusion of some factor, presumably secreted by the irradiated cells. Even with an oversimplified simulation, we could demonstrate a sizeable difference in the proliferation rate of non-irradiated cells, the proliferation acceleration being much larger for the global than the local effect, for relatively small fractions of irradiated cells in the colony.

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

    NASA Astrophysics Data System (ADS)

    Chen, Yanguang

    2016-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  20. Damage Evolution On Mechanical Parts Under Cyclic Loading

    NASA Astrophysics Data System (ADS)

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

    2007-05-01

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

  1. Nonlinear flutter of composite plates with damage evolution

    NASA Astrophysics Data System (ADS)

    Kim, Young I.; Stragnac, Thomas W.; Kurdila, Andrew J.

    1993-04-01

    The investigators present a study of dynamic and aeroelastic response of structures which evolve due to damage. Aeroelastic response is shown to be dependent upon the distribution and accumulation of damage. In turn, the damage is dependent upon the presence of the aerodynamic loads. Dynamic characteristics are unique to the coupled damage/aeroelastic system and are developed as part of the solution methodology. In this study, the damage is due to the natural progression of microcracking of the composite structure; yet, the control model presented is appropriate for distributed actuation systems. The stability boundary for aeroelastic flutter and divergence evolves due to damage. Control design based upon the min-max control theory is presented which addresses model uncertainties.

  2. The Coffin-Manson law as a consequence of the statistical nature of the LCF surface damage

    NASA Astrophysics Data System (ADS)

    Brechet, Y.; Magnin, T.; Sornette, D.

    1992-09-01

    The transition between the Coffin-Manson law in low cycle fatigue and the Basquin law in high cycle fatigue is shown to be closely related to the microstructural aspects of damage accumulation in the two different fatigue domains. In LCF, the surface extension of microcracks is predominant whereas their bulk propagation is dominating in HCF. Along these lines, the Coffin-Manson law is derived using standard methods of statistical physics of disordered systems. The university of the Coffin-Manson exponent for single-phased materials is shown to be a direct consequence of the statistical nature of damage accumulation due to the growth and the interaction of surface microcracks.

  3. Dynamic deformation and fracture of single crystal silicon: Fracture modes, damage laws, and anisotropy

    SciTech Connect

    Huang, J. Y.; E, J. C.; Huang, J. W.; Sun, T.; Fezzaa, K.; Xu, S. L.; Luo, S. N.

    2016-05-25

    Impact fracture of single-crystal Si is critical to long-term reliability of electronic devices and solar cells for its wide use as components or substrates in semiconductor industry. Single-crystal Si is loaded along two different crystallographic directions with a split Hopkinson pressure bar integrated with an in situ x-ray imaging and diffraction system. Bulk stress histories are measured, simultaneously with x-ray phase contrast imaging (XPCI) and Laue diffraction. Damage evolution is quantified with grayscale maps from XPCI. Single-crystal Si exhibits pronounced anisotropy in fracture modes, and thus fracture strengths and damage evolution. For loading along [11¯ 0] and viewing along [001], (1¯1¯0)[11¯ 0] cleavage is activated and induces horizontal primary cracks followed by perpendicular wing cracks. However, for loading along [011¯] and viewing along [111], random nucleation and growth of shear and tensile-splitting crack networks lead to catastrophic failure of materials with no cleavage. The primary-wing crack mode leads to a lower characteristic fracture strength due to predamage, but a more concentrated strength distribution, i.e., a higher Weibull modulus, compared to the second loading case. Furthermore, the sequential primary cracking, wing cracking and wing-crack coalescence processes result in a gradual increase of damage with time, deviating from theoretical predictions. Particle size and aspect ratios of fragments are discussed with postmortem fragment analysis, which verifies fracture modes observed in XPCI.

  4. Dynamic deformation and fracture of single crystal silicon: Fracture modes, damage laws, and anisotropy

    DOE PAGES

    Huang, J. Y.; E, J. C.; Huang, J. W.; ...

    2016-05-25

    Impact fracture of single-crystal Si is critical to long-term reliability of electronic devices and solar cells for its wide use as components or substrates in semiconductor industry. Single-crystal Si is loaded along two different crystallographic directions with a split Hopkinson pressure bar integrated with an in situ x-ray imaging and diffraction system. Bulk stress histories are measured, simultaneously with x-ray phase contrast imaging (XPCI) and Laue diffraction. Damage evolution is quantified with grayscale maps from XPCI. Single-crystal Si exhibits pronounced anisotropy in fracture modes, and thus fracture strengths and damage evolution. For loading along [11¯ 0] and viewing along [001],more » (1¯1¯0)[11¯ 0] cleavage is activated and induces horizontal primary cracks followed by perpendicular wing cracks. However, for loading along [011¯] and viewing along [111], random nucleation and growth of shear and tensile-splitting crack networks lead to catastrophic failure of materials with no cleavage. The primary-wing crack mode leads to a lower characteristic fracture strength due to predamage, but a more concentrated strength distribution, i.e., a higher Weibull modulus, compared to the second loading case. Furthermore, the sequential primary cracking, wing cracking and wing-crack coalescence processes result in a gradual increase of damage with time, deviating from theoretical predictions. Particle size and aspect ratios of fragments are discussed with postmortem fragment analysis, which verifies fracture modes observed in XPCI.« less

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

    PubMed Central

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

    2013-01-01

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

  6. An existence result for a model of complete damage in elastic materials with reversible evolution

    NASA Astrophysics Data System (ADS)

    Bonetti, Elena; Freddi, Francesco; Segatti, Antonio

    2017-01-01

    In this paper, we consider a model describing evolution of damage in elastic materials, in which stiffness completely degenerates once the material is fully damaged. The model is written by using a phase transition approach, with respect to the damage parameter. In particular, a source of damage is represented by a quadratic form involving deformations, which vanishes in the case of complete damage. Hence, an internal constraint is ensured by a maximal monotone operator. The evolution of damage is considered "reversible", in the sense that the material may repair itself. We can prove an existence result for a suitable weak formulation of the problem, rewritten in terms of a new variable (an internal stress). Some numerical simulations are presented in agreement with the mathematical analysis of the system.

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

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

    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

  8. The effects of self-interstitial clusters on cascade defect evolution beyond the primary damage state

    SciTech Connect

    Heinisch, H.L.

    1997-04-01

    The intracascade evolution of the defect distributions of cascades in copper is investigated using stochastic annealing simulations applied to cascades generated with molecular dynamics (MD). The temperature and energy dependencies of annihilation, clustering and free defect production are determined for individual cascades. The annealing simulation results illustrate the strong influence on intracascade evolution of the defect configuration existing in the primary damage state. Another factor significantly affecting the evolution of the defect distribution is the rapid one-dimensional diffusion of small, glissile interstitial loops produced directly in cascades. This phenomenon introduces a cascade energy dependence of defect evolution that is apparent only beyond the primary damage state, amplifying the need for further study of the annealing phase of cascade evolution and for performing many more MD cascade simulations at higher energies.

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

    PubMed

    Abzhanov, Arhat

    2013-12-01

    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.

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

    PubMed

    Gong, Tao; Shuai, Lan

    2014-01-01

    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 λ 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.

  11. Gradation of mechanical properties in gas-diffusion electrode. Part 2: Heterogeneous carbon fiber and damage evolution in cell layers

    NASA Astrophysics Data System (ADS)

    Poornesh, K. K.; Cho, C. D.; Lee, G. B.; Tak, Y. S.

    In PEM fuel cell, gas-diffusion electrode (GDE) plays very significant role in force transmission from bipolar plate to the membrane. This paper investigates the effects of geometrical heterogeneities of gas-diffusion electrode layer (gas-diffusion layer (GDL) and catalyst layer (CL)) on mechanical damage evolution and propagation. We present a structural integrity principle of membrane electrode assembly (MEA) based on the interlayer stress transfer capacity and corresponding cell layer material response. Commonly observable damages such as rupture of hydrophobic coating and breakage of carbon fiber in gas-diffusion layer are attributed to the ductile to brittle phase transition within a single carbon fiber. Effect of material inhomogeneity on change in modulus, hardness, contact stiffness, and electrical contact resistance is also discussed. Fracture statistics of carbon fiber and variations in flexural strength of GDL are studied. The damage propagation in CL is perceived to be influenced by the type of gradation and the vicinity from which crack originates. Cohesive zone model has been proposed based on the traction-separation law to investigate the damage propagation throughout the two interfaces (carbon fiber/CL and CL/membrane).

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

    NASA Astrophysics Data System (ADS)

    Main, Ian

    2014-05-01

    '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

  13. The evolution of damage in tritium exposed copper

    SciTech Connect

    Goods, S.H. )

    1991-02-01

    Severe microstructural damage has been observed in polycrystalline OFHC copper specimens thermally exposed to high pressure tritium gas at temperatures {le}200 {degree}C, but not at 300 {degree}C. No such damage occurs in single crystal specimens exposed under identical conditions, regardless of temperature. In the polycrystals, the damage takes the form of very flat, crack-like intergranular cavities. It is found that the cavitation evolves slowly with time. For short exposure times, cavities as small as 0.1 {mu}m are observed. In specimens subjected to the longest aging times, the cavities grow and link until entire grain boundary facets fail. The driving force for the growth of these cavities is attributed to the internal gas pressure of helium-3 generated by the decay of tritium. The growth kinetics of cavity microstructure are described by a coupled grain boundary, surface self-diffusion process. The tritium exposure profoundly affects the mechanical properties of the polycrystalline material, inducing a severe loss in ductility. In concert with the observed ductility loss is a change in fracture morphology from transgranular ductile rupture to intergranular fracture. Examination of the resulting grain boundary facets reveals a dimple structure. The spacing of these dimples can be correlated with the spacing of the exposure-induced grain boundary cavities.

  14. 32 CFR 536.50 - Determination of damages-applicable law.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... giving rise to the claim occurred, including choice of law rules, is applicable. Therefore, the law of... claims accruing on or after September 1, 1995. The law of the place of the incident giving rise to...

  15. Studying the laws of software evolution in a long-lived FLOSS project

    PubMed Central

    Gonzalez-Barahona, Jesus M; Robles, Gregorio; Herraiz, Israel; Ortega, Felipe

    2014-01-01

    Some free, open-source software projects have been around for quite a long time, the longest living ones dating from the early 1980s. For some of them, detailed information about their evolution is available in source code management systems tracking all their code changes for periods of more than 15 years. This paper examines in detail the evolution of one of such projects, glibc, with the main aim of understanding how it evolved and how it matched Lehman's laws of software evolution. As a result, we have developed a methodology for studying the evolution of such long-lived projects based on the information in their source code management repository, described in detail several aspects of the history of glibc, including some activity and size metrics, and found how some of the laws of software evolution may not hold in this case. © 2013 The Authors. Journal of Software: Evolution and Process published by John Wiley & Sons Ltd. PMID:25893093

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

    PubMed

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

    2012-07-27

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

  17. Microstructural effects on damage evolution in shocked copper polycrystals

    DOE PAGES

    Lieberman, Evan J.; Lebensohn, Ricardo A.; Menasche, David B.; ...

    2016-07-01

    Three-dimensional crystal orientation fields of a copper sample, characterized before and after shock loading using High Energy Diffraction Microscopy, are used for input and validation of direct numerical simulations using a Fast Fourier Transform (FFT)-based micromechanical model. The locations of the voids determined by X-ray tomography in the incipiently-spalled sample, predominantly found near grain boundaries, were traced back and registered to the pre-shocked microstructural image. Using FFT-based simulations with direct input from the initial microstructure, micromechanical fields at the shock peak stress were obtained. Statistical distributions of micromechanical fields restricted to grain boundaries that developed voids after the shock aremore » compared with corresponding distributions for all grain boundaries. Distributions of conventional measures of stress and strain (deviatoric and mean components) do not show correlation with the locations of voids in the post-shocked image. Neither does stress triaxiality, surface traction or grain boundary inclination angle, in a significant way. On the other hand, differences in Taylor factor and accumulated plastic work across grain boundaries do correlate with the occurrence of damage. As a result, damage was observed to take place preferentially at grain boundaries adjacent to grains having very different plastic response.« less

  18. Microstructural effects on damage evolution in shocked copper polycrystals

    SciTech Connect

    Lieberman, Evan J.; Lebensohn, Ricardo A.; Menasche, David B.; Bronkhorst, Curt Allan; Rollett, Anthony D.

    2016-07-01

    Three-dimensional crystal orientation fields of a copper sample, characterized before and after shock loading using High Energy Diffraction Microscopy, are used for input and validation of direct numerical simulations using a Fast Fourier Transform (FFT)-based micromechanical model. The locations of the voids determined by X-ray tomography in the incipiently-spalled sample, predominantly found near grain boundaries, were traced back and registered to the pre-shocked microstructural image. Using FFT-based simulations with direct input from the initial microstructure, micromechanical fields at the shock peak stress were obtained. Statistical distributions of micromechanical fields restricted to grain boundaries that developed voids after the shock are compared with corresponding distributions for all grain boundaries. Distributions of conventional measures of stress and strain (deviatoric and mean components) do not show correlation with the locations of voids in the post-shocked image. Neither does stress triaxiality, surface traction or grain boundary inclination angle, in a significant way. On the other hand, differences in Taylor factor and accumulated plastic work across grain boundaries do correlate with the occurrence of damage. As a result, damage was observed to take place preferentially at grain boundaries adjacent to grains having very different plastic response.

  19. General introduction to microstructural evolution under cascade damage conditions

    SciTech Connect

    Wiedersich, H.

    1993-06-01

    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.

  20. The Coffin-Manson law as a consequence of the statistical nature of the LCF surface damage

    SciTech Connect

    Brechet, Y.; Magnin, T.; Sornette, D. Lille I, Universite, Villeneuve-d'Ascq Nice, Universite, )

    1992-09-01

    The transition between the Coffin-Manson law in low cycle fatigue and the Basquin law in high cycle fatigue is shown to be closely related to the microstructural aspects of damage accumulation in the two different fatigue domains. In LCF, the surface extension of microcracks is predominant whereas their bulk propagation is dominating in HCF. Along these lines, the Coffin-Manson law is derived using standard methods of statistical physics of disordered systems. The university of the Coffin-Manson exponent for single-phased materials is shown to be a direct consequence of the statistical nature of damage accumulation due to the growth and the interaction of surface microcracks. 22 refs.

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

    NASA Astrophysics Data System (ADS)

    Suzuki, T.

    2010-12-01

    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

  2. On compression and damage evolution in PTFE and PEEK

    NASA Astrophysics Data System (ADS)

    Rau, C.; Parry, S.; Garcea, S. C.; Bourne, N. K.; McDonald, S. A.; Eastwood, D. S.; Brown, E. N.; Withers, P. J.

    2017-01-01

    The well-known Taylor cylinder impact test, that follows the impact of a flat-ended cylindrical rod onto a rigid stationary anvil, is conducted over a range of impact speeds for two polymers, PTFE and PEEK. In previous work experiments and a model were developed to capture the deformation behaviour of the rod after impact. A distinctive feature of these works was that a region in which both spatial and temporal variation of both longitudinal and radial deformation showed evidence of changes in phase within the material. This region is X-ray imaged in a range of impacted targets at the I13 Imaging and Coherence beam line at the Diamond synchrotron. Further techniques were fielded to resolve compressed regions within the recovered polymer cylinders that showed a fracture zone in the impact region. This shows the transit of damage from ductile to brittle failure results from previously undetected internal failure.

  3. Spin-coating process evolution and reproducibility for power-law fluids.

    PubMed

    Jardim, P L G; Michels, A F; Horowitz, F

    2014-03-20

    A distinct development of an exact analytical solution for power-law fluids during the spin-coating process is presented for temporal and spatial thickness evolution, after steady state conditions are attained. This solution leads to the definition of a characteristic time, related to the memory of the initial thickness profile. Previously obtained experimental data, for several rotation speeds and carboxymetilcellulose concentrations in water, are quantitatively analyzed through the evaluation of their characteristic times and compared with theoretical predictions, thus allowing better understanding of thickness profile evolution and of process reproducibility.

  4. Particle swarms in gases: the velocity-average evolution equations from Newton's law.

    PubMed

    Ferrari, Leonardo

    2003-08-01

    The evolution equation for a generic average quantity relevant to a swarm of particles homogeneously dispersed in a uniform gas, is obtained directly from the Newton's law, without having recourse to the (intermediary) Boltzmann equation. The procedure makes use of appropriate averages of the term resulting from the impulsive force (due to collisions) in the Newton's law. When the background gas is assumed to be in thermal equilibrium, the obtained evolution equation is shown to agree with the corresponding one following from the Boltzmann equation. But the new procedure also allows to treat physical situations in which the Boltzmann equation is not valid, as it happens when some correlation exists (or is assumed) between the velocities of swarm and gas particles.

  5. Asymmetrical Damage Partitioning in Bacteria: A Model for the Evolution of Stochasticity, Determinism, and Genetic Assimilation.

    PubMed

    Chao, Lin; Rang, Camilla Ulla; Proenca, Audrey Menegaz; Chao, Jasper Ubirajara

    2016-01-01

    Non-genetic phenotypic variation is common in biological organisms. The variation is potentially beneficial if the environment is changing. If the benefit is large, selection can favor the evolution of genetic assimilation, the process by which the expression of a trait is transferred from environmental to genetic control. Genetic assimilation is an important evolutionary transition, but it is poorly understood because the fitness costs and benefits of variation are often unknown. Here we show that the partitioning of damage by a mother bacterium to its two daughters can evolve through genetic assimilation. Bacterial phenotypes are also highly variable. Because gene-regulating elements can have low copy numbers, the variation is attributed to stochastic sampling. Extant Escherichia coli partition asymmetrically and deterministically more damage to the old daughter, the one receiving the mother's old pole. By modeling in silico damage partitioning in a population, we show that deterministic asymmetry is advantageous because it increases fitness variance and hence the efficiency of natural selection. However, we find that symmetrical but stochastic partitioning can be similarly beneficial. To examine why bacteria evolved deterministic asymmetry, we modeled the effect of damage anchored to the mother's old pole. While anchored damage strengthens selection for asymmetry by creating additional fitness variance, it has the opposite effect on symmetry. The difference results because anchored damage reinforces the polarization of partitioning in asymmetric bacteria. In symmetric bacteria, it dilutes the polarization. Thus, stochasticity alone may have protected early bacteria from damage, but deterministic asymmetry has evolved to be equally important in extant bacteria. We estimate that 47% of damage partitioning is deterministic in E. coli. We suggest that the evolution of deterministic asymmetry from stochasticity offers an example of Waddington's genetic assimilation

  6. Law.

    ERIC Educational Resources Information Center

    Walker, W. R.; Cox, W. E.

    1978-01-01

    Presents a literature review of the legal issues relative to water quality covering publications of 1977. Consideration is given to federal laws, Supreme Court cases, and the impact of federal environmental laws on local government. A list of 47 references is also presented. (HM)

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  8. Evolution of a Subducted Slab with Viscosity Controlled by Damage and Healing Processes

    NASA Astrophysics Data System (ADS)

    Bellas, A. S.; Zhong, S.; Bercovici, D.

    2015-12-01

    The rheology and viscosity in the lithosphere and mantle are fundamental to understanding mantle and lithospheric dynamics including the emergence and evolution of plate tectonics on Earth and other planets. The viscosity is controlled by temperature, stress, and grain size, and particularly, the grain size leads to history-dependence in viscosity through damaging and healing processes at grain scales. Motivated by studies by Bercovici, Schubert and Ricard, [2015] and Schmalholz [2011], in this study, we investigate the rheology and viscosity in the vicinity of a subducted slab which hangs from the overlying lithosphere. We calculate both numerically and analytically the timescale on which viscosity diminishes to a minimum as a result of grain size reduction caused by buoyancy induced deformation and damage. The evolution equation for grain size (or fineness as the inverse grain size) is solved with a second order Runge-Kutta scheme, together with a tracer method, and the mantle dynamics is solved with Citcom which has been modified to include grain size dependent viscosity. We initially do not allow the slab's buoyancy to evolve. The analytical solution for viscosity evolution and its timescale is derived under the assumption that stress is constant. We find that the analytical and numerical solutions of viscosity reduction with time are in good agreement with each other. In all cases, when Dσ2 > H, where D is damage parameter, σ stress, and H healing parameter, which ensures damage dominates over healing, the timescale of the viscosity reduction is inversely proportional to D, and is on the order of 1 Myr for an Earth-like planet. Our work implies that the evolution of rheology in a damage-dominated regime around a subducted slab is a rapid process. We will extend the models to allow slab buoyancy to co-evolve with grain size and viscosity to examine the effect on this characteristic timescale and slab dynamics.

  9. Impact of Gas Adsorption Induced Coal Matrix Damage on the Evolution of Coal Permeability

    NASA Astrophysics Data System (ADS)

    Zhu, W. C.; Wei, C. H.; Liu, J.; Xu, T.; Elsworth, D.

    2013-11-01

    It has been widely reported that coal permeability can change from reduction to enhancement due to gas adsorption even under the constant effective stress condition, which is apparently inconsistent with the classic theoretical solutions. This study addresses this inconsistency through explicit simulations of the dynamic interactions between coal matrix swelling/shrinking induced damage and fracture aperture alteration, and translations of these interactions to permeability evolution under the constant effective stress condition. We develop a coupled coal-gas interaction model that incorporates the material heterogeneity and damage evolution of coal, which allows us to couple the progressive development of damage zone with gas adsorption processes within the coal matrix. For the case of constant effective stress, coal permeability changes from reduction to enhancement while the damage zone within the coal matrix develops from the fracture wall to further inside the matrix. As the peak Langmuir strain is approached, the decrease of permeability halts and permeability increases with pressure. The transition of permeability reduction to permeability enhancement during gas adsorption, which may be closely related to the damage zone development in coal matrix, is controlled by coal heterogeneity, external boundary condition, and adsorption-induced swelling.

  10. The second law of thermodynamics under unitary evolution and external operations

    SciTech Connect

    Ikeda, Tatsuhiko N.; Sakumichi, Naoyuki; Polkovnikov, Anatoli; Ueda, Masahito

    2015-03-15

    The von Neumann entropy cannot represent the thermodynamic entropy of equilibrium pure states in isolated quantum systems. The diagonal entropy, which is the Shannon entropy in the energy eigenbasis at each instant of time, is a natural generalization of the von Neumann entropy and applicable to equilibrium pure states. We show that the diagonal entropy is consistent with the second law of thermodynamics upon arbitrary external unitary operations. In terms of the diagonal entropy, thermodynamic irreversibility follows from the facts that quantum trajectories under unitary evolution are restricted by the Hamiltonian dynamics and that the external operation is performed without reference to the microscopic state of the system.

  11. Modeling of delamination damage evolution in laminated composites subjected to low velocity impact

    NASA Technical Reports Server (NTRS)

    Lo, David C.; Allen, David H.

    1994-01-01

    This study examines the delamination evolution, under quasi-static conditions, of laminated polymeric composites with mechanically nonlinear resin rich interfaces. The constitutive behavior of the interface is represented by two models developed by Needleman and Tvegaard. These models assumed that the interfacial tractions, a function of only the interfacial displacement, will behave similarly to the interatomic forces generated during the interatomic seperation. The interface material's parameters control the load at which the delamination growth initiates and the final delamination size. A wide range of damage accumulation responses have been obtained by varying the model parameters. These results show that Tvergaard's model has been found to be better suited of the two models in predicting damage evolution for the configurations examined.

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

    SciTech Connect

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

    2012-07-09

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

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

    NASA Astrophysics Data System (ADS)

    Koonin, Eugene

    2003-03-01

    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

  14. Intraspecific competition facilitates the evolution of tolerance to insect damage in the perennial plant Solanum carolinense.

    PubMed

    McNutt, David W; Halpern, Stacey L; Barrows, Kahaili; Underwood, Nora

    2012-12-01

    Tolerance to herbivory (the degree to which plants maintain fitness after damage) is a key component of plant defense, so understanding how natural selection and evolutionary constraints act on tolerance traits is important to general theories of plant-herbivore interactions. These factors may be affected by plant competition, which often interacts with damage to influence trait expression and fitness. However, few studies have manipulated competitor density to examine the evolutionary effects of competition on tolerance. In this study, we tested whether intraspecific competition affects four aspects of the evolution of tolerance to herbivory in the perennial plant Solanum carolinense: phenotypic expression, expression of genetic variation, the adaptive value of tolerance, and costs of tolerance. We manipulated insect damage and intraspecific competition for clonal lines of S. carolinense in a greenhouse experiment, and measured tolerance in terms of sexual and asexual fitness components. Compared to plants growing at low density, plants growing at high density had greater expression of and genetic variation in tolerance, and experienced greater fitness benefits from tolerance when damaged. Tolerance was not costly for plants growing at either density, and only plants growing at low density benefited from tolerance when undamaged, perhaps due to greater intrinsic growth rates of more tolerant genotypes. These results suggest that competition is likely to facilitate the evolution of tolerance in S. carolinense, and perhaps in other plants that regularly experience competition, while spatio-temporal variation in density may maintain genetic variation in tolerance.

  15. Laws of conservation as related to brain growth, aging, and evolution: symmetry of the minicolumn.

    PubMed

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

    2011-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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.

  17. A Numerical Method for Simulating the Microscopic Damage Evolution in Composites Under Uniaxial Transverse Tension

    NASA Astrophysics Data System (ADS)

    Zhi, Jie; Zhao, Libin; Zhang, Jianyu; Liu, Zhanli

    2016-06-01

    In this paper, a new numerical method that combines a surface-based cohesive model and extended finite element method (XFEM) without predefining the crack paths is presented to simulate the microscopic damage evolution in composites under uniaxial transverse tension. The proposed method is verified to accurately capture the crack kinking into the matrix after fiber/matrix debonding. A statistical representative volume element (SRVE) under periodic boundary conditions is used to approximate the microstructure of the composites. The interface parameters of the cohesive models are investigated, in which the initial interface stiffness has a great effect on the predictions of the fiber/matrix debonding. The detailed debonding states of SRVE with strong and weak interfaces are compared based on the surface-based and element-based cohesive models. The mechanism of damage in composites under transverse tension is described as the appearance of the interface cracks and their induced matrix micro-cracking, both of which coalesce into transversal macro-cracks. Good agreement is found between the predictions of the model and the in situ experimental observations, demonstrating the efficiency of the presented model for simulating the microscopic damage evolution in composites.

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

    NASA Astrophysics Data System (ADS)

    Cretegny, Laurent

    2000-10-01

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

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

    NASA Astrophysics Data System (ADS)

    Kuan, Yean-Der

    2000-10-01

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

  20. Damage evolution on Sm and O sublattices in Au-implanted samarium titanate pyrochlore

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Weber, W. J.; Shutthanandan, V.; Devanathan, R.; Thevuthasan, S.; Balakrishnan, G.; Paul, D. M.

    2004-03-01

    Damage evolution on the Sm and O sublattices in Sm2Ti2O7 single crystals irradiated with 1 MeV Au2+ ions at 170, 300, and 700 K was studied by Rutherford backscattering spectroscopy and 16O(d,p)17O nuclear reaction analysis along the <001> direction. The damage accumulation behavior at each irradiation temperature indicates that the relative disorder on the O sublattice is higher than that on the Sm sublattice, and the relative disorder, determined by ion channeling, on each sublattice follows a nonlinear dependence on dose that is well described by a disorder accumulation model. While there is little difference in damage accumulation behavior on the Sm sublattice at 170 and 300 K irradiation, the rate of damage accumulation decreases dramatically at 700 K due to dynamic recovery processes. The critical dose for amorphization at 170 and 300 K is 0.14 displacements per atom (dpa), and a higher dose of 0.22 dpa is observed under irradiation at 700 K. During thermal annealing in an 18O environment, a significant increase in the 18O exchange was observed between 800 and 900 K, which is just below the previously determined critical temperature, 950 K, for amorphization in Sm2Ti2O7, suggesting that the mobility of O vacancies may be important in defining the critical temperature.

  1. Damage and the Gutenberg-Richter Law: from simple models to natural earthquake fault systems

    NASA Astrophysics Data System (ADS)

    Tiampo, K. F.; Klein, W.; Rundle, J. B.; Dominguez, R.; Serino, C.

    2010-12-01

    Natural earthquake fault systems are highly nonhomogeneous in space, where these inhomogeneities occur because the earth is made of a variety of materials which hold and dissipate stress differently. One way that the inhomogeneous nature of fault systems manifests itself is in the spatial patterns which emerge in seismicity graphs (Tiampo et al., 2002, 2007). Despite their inhomogeneous nature, real faults are often modeled as spatially homogeneous systems. One argument for this approach is that earthquake faults experience long range stress transfer, and if this range is longer than the length scales associated with the inhomogeneities of the system, the dynamics of the system may be unaffected by their presence. However, it is not clear that this is the case. In this work we study the scaling of an earthquake model that is a variation of the Olami-Feder-Christensen (OFC) model, in order to explore the effect of spatial inhomogeneities on earthquake-like systems when interaction ranges are long, but not necessarily longer than the distances associated with those inhomogeneities (Rundle and Jackson, 1977; Olami et al., 1988). For long ranges and without inhomogeneities, such models have been found to produce scaling similar to GR scaling found in real earthquake systems (Rundle and Klein, 1993). In the earthquake models discussed here, damage is distributed inhomogeneously throughout and the interaction ranges, while long, are not longer than all of the damage length scales. We find that the scaling depends not only on the amount of damage, but also on the spatial distribution of that damage. In addition, we study the behaviour of particular natural earthquake faults and the spatial and temporal variation of GR scaling in those systems, in order to compare them with various damage cases from the simulations.

  2. On the Physical Basis of Rate Law Formulations for River Evolution, and their Applicability to the Simulation of Evolution after Earthquakes

    NASA Astrophysics Data System (ADS)

    An, C.; Parker, G.; Fu, X.

    2015-12-01

    River morphology evolves in response to trade-offs among a series of environmental forcing factors, and this evolution will be disturbed if such environmental factors change. One example of response to chronic disturbance is the intensive river evolution after earthquakes in southwest China's mountain areas. When simulating river morphological response to environmental disturbance, an exponential rate law with a specified characteristic response time is often regarded as a practical tool for quantification. As conceptual models, empirical rate law formulations can be used to describe broad brush morphological response, but their physically basis is not solid in that they do not consider the details of morphodynamic processes. Meanwhile, river evolution can also be simulated with physically-based morphodynamic models which conserve sediment via the Exner equation. Here we study the links between the rate law formalism and the Exner equation through solving the Exner equation mathematically and numerically. The results show that, when implementing a very simplified form of a relation for bedload transport, the Exner equation can be reduced to the diffusion equation, the solution of which is a Gaussian function. This solution coincides with the solution associated with rate laws, thus providing a physical basis for such formulations. However, when the complexities of a natural river are considered, the solution of the Exner equation will no longer be a simple Gaussian function. Under such circumstances, the rate law becomes invalid, and a full understanding of the response of rivers to earthquakes requires a complete morphodynamic model.

  3. Implications Of Fault Damaged Bedrock To Tectonic and Landscape Evolution In Coastal Alaska

    NASA Astrophysics Data System (ADS)

    Boucher, A.; Koons, P. O.; Roy, S. G.; Birkel, S. D.; Kaluzienski, L. M.; Campbell, S. W.

    2015-12-01

    Bedrock material strength properties heavily impact erosion rates in temperate glacial environments. We focus on the influence of localized tectonic crustal weakening in southeast Alaska on modern glacial erosion rates, thereby quantifying a primary feedback in tectonic/climatic coupling. Southeast Alaska, with its coincident high strain rates, vigorous glacial erosion and rapid sedimentation rates, provides an excellent setting in which to evaluate this interaction. To characterize the relationship between fault damage and glacial incision, we collected data in transects across the strike-slip Fairweather Fault in Yakutat and Disenchantment Bays, in deglaciated valleys below the Mendenhall, Herbert, Ptarmigan, and Lemon Creek Glaciers on the perimeter of the Juneau Icefield, and on deglaciated nunataks on the Echo and Vaughan Lewis Glaciers in the interior of the Juneau Icefield. The mechanical properties of the bedrock are characterized by estimates of fault spacing and material cohesion. In structurally-controlled bedrock valleys exploited by glaciers, fracture spacing may vary by several orders of magnitude across fault damage zones, from more than 10 m to less than 0.1 m. Analysis of active and quiescent fault zones indicate that this variation approximates a power law relationship and correlates with a gradient in cohesive strength varying from greater than 50 MPa to less than 50 kPa between intact bedrock and the core of fault damage zones. The width and orientation of the damage zones is highly variable and we have chosen our field sites to sample zones of very large total displacement, up to kilometers along the Fairweather Fault, and substantially smaller displacements, down to centimeters for the Juneau Icefield locales. Using a Cordilleran Ice sheet model to extend our modern observations into last glacial maximum conditions, we predict both erosion rates and sediment provenance for a material strength pattern influenced by tectonically induced fault

  4. Detection of damage in multiwire cables based on wavelet entropy evolution

    NASA Astrophysics Data System (ADS)

    Ibáñez, Flor; Baltazar, Arturo; Mijarez, Rito

    2015-08-01

    Multiwire cables are widely used in important engineering structures. Since they are exposed to several dynamic and static loads as well as detrimental environmental conditions, their structural health can be compromised. Due to the critical role played by multiwire cables, it is necessary to develop a non-destructive health monitoring method to maintain their structure and proper performance. Ultrasonic inspection using guided waves is a promising non-destructive damage monitoring technique for rods, single and multiwire cables. However, the propagated guided waves are composed of an infinite number of dispersive vibrational modes making their analysis difficult. In this work, an entropy-based method to identify small changes in non-stationary signals is proposed. An experimental system to capture and post-process acoustic signals is implemented. The discrete wavelet transform is computed in order to obtain the reconstructed wavelet coefficients of the signals and to analyze the energy at different scales. The use of the concept of entropy evolution of non-stationary signals to detect damage in multiwire cables is evaluated. The results show that there is a correlation between the entropy value and level of damage of the cable including breaking of single wires and change in the mechanical contact conditions among the wires. It is found that the studied method has low sensitivity to signal noise and can reduce the computational complexity encountered in a typical time-frequency analysis.

  5. Detection of structural damage in multiwire cables by monitoring the entropy evolution of wavelet coefficients

    NASA Astrophysics Data System (ADS)

    Ibáñez, Flor; Baltazar, Arturo; Mijarez, Rito; Aranda, Jorge

    2015-03-01

    Multiwire cables are widely used in important civil structures. Since they are exposed to several dynamic and static loads, their structural health can be compromised. The cables can also be submitted to mechanical contact, tension and energy propagation in addition to changes in size and material within their wires. Due to the critical role played by multiwire cables, it is necessary to develop a non-destructive health monitoring method to maintain their structure and proper performance. Ultrasonic inspection using guided waves is a promising non-destructive damage monitoring technique for rods, single wires and multiwire cables. The propagated guided waves are composed by an infinite number of vibrational modes making their analysis difficult. In this work, an entropy-based method to identify small changes in non-stationary signals is proposed. A system to capture and post-process acoustic signals is implemented. The Discrete Wavelet Transform (DWT) is computed in order to obtain the reconstructed wavelet coefficients of the signals and to analyze the energy at different scales. The feasibility of using the concept of entropy evolution of non-stationary signals to detect damage in multiwire cables is evaluated. The results show that there is a high correlation between the entropy value and damage level of the cable. The proposed method has low sensitivity to noise and reduces the computational complexity found in a typical time-frequency analysis.

  6. An incremental-iterative method for modeling damage evolution in voxel-based microstructure models

    NASA Astrophysics Data System (ADS)

    Zhu, Qi-Zhi; Yvonnet, Julien

    2015-02-01

    Numerical methods motivated by rapid advances in image processing techniques have been intensively developed during recent years and increasingly applied to simulate heterogeneous materials with complex microstructure. The present work aims at elaborating an incremental-iterative numerical method for voxel-based modeling of damage evolution in quasi-brittle microstructures. The iterative scheme based on the Lippmann-Schwinger equation in the real space domain (Yvonnet, in Int J Numer Methods Eng 92:178-205, 2012) is first cast into an incremental form so as to implement nonlinear material models efficiently. In the proposed scheme, local strain increments at material grid points are computed iteratively by a mapping operation through a transformation array, while local stresses are determined using a constitutive model that accounts for material degradation by damage. For validation, benchmark studies and numerical simulations using microtomographic data of concrete are performed. For each test, numerical predictions by the incremental-iterative scheme and the finite element method, respectively, are presented and compared for both global responses and local damage distributions. It is emphasized that the proposed incremental-iterative formulation can be straightforwardly applied in the framework of other Lippmann-Schwinger equation-based schemes, like the fast Fourier transform method.

  7. Evolution of damage fraction due to dense ionizing irradiation on TiO2 film

    NASA Astrophysics Data System (ADS)

    Kumar, Avesh; Kanjilal, D.; Mohanty, T.

    2013-10-01

    The evolution of damage fraction during dense ionizing irradiation at various fluences using 100 MeV Ag ion is studied. Irradiation induced modification of surface roughness and surface potential of titanium dioxide nanocrystalline thin films are estimated. TiO2 thin films deposited on Si (1 0 0) substrate were irradiated by 100 MeV Ag ion beam with varying fluences. Ion bombardment generates point and extended defects in TiO2 thin films due to dense electronic excitation. The surface morphology and surface roughness of irradiated and pristine thin films were measured using atomic force microscopy. The changes in surface potential of pristine as well as Ag ion beam irradiated thin films were measured from contact potential difference between TiO2 thin film (one electrode) of unknown work function and Au (reference electrode) of known work function using scanning Kelvin probe microscopy. The defect size and damage fraction are calculated from exponential fitting of variation of both contact surface potential difference and roughness exponent with fluence.

  8. Effect of heat treatments on mechanical properties and damage evolution of thixoformed aluminium alloys

    SciTech Connect

    Cavaliere, P. . E-mail: pasquale.cavaliere@unile.it; Cerri, E.; Leo, P.

    2005-07-15

    In the present work, the effects of heat treatments on mechanical properties, microstructure evolution and damage resulting from plastic deformation of thixoformed A319 and A356 aluminium alloys, are studied. The thixoforming process can lead to the production of components that are characterized by very good mechanical properties and low porosity with a globular microstructure which is fine and uniform. The mechanical properties can be further improved through heat treatments such as T5 and T6. The prime factor influencing the damage in the alloys belonging to the Al-Si system is represented by decohesion of silicon particles resulting from the stress concentration at the particle-matrix interfaces. A statistical analysis of fractured particles after tensile tests in the as-cast and as-treated condition has been carried out in the present work; optical and scanning electron microscopy techniques have been used to characterize the microstructure and fracture surfaces of the specimens and the results are fully presented.

  9. PCA algorithm for detection, localisation and evolution of damages in gearbox bearings

    NASA Astrophysics Data System (ADS)

    Pirra, M.; Gandino, E.; Torri, A.; Garibaldi, L.; Machorro-López, J. M.

    2011-07-01

    A fundamental aspect when dealing with rolling element bearings, which often represent a key component in rotating machineries, consists in correctly identifying a degraded behaviour of a bearing with a reasonable level of confidence. This is one of the main requirements a health and usage monitoring system (HUMS) should have. This paper introduces a monitoring technique for the diagnosis of bearing faults based on Principal Component Analysis (PCA). This method overcomes the problem of acquiring data under different environmental conditions (hardly biasing the data) and allows accurate damage recognition, also assuring a rather low number of False Alarms (FA). In addition, a novel criterion is proposed in order to isolate the area in which the faulty bearing stands. Another useful feature of this PCA-based method concerns the capability to observe an increasing trend in the evolution of bearing degradation. The described technique is tested on an industrial rig (designed by Avio S.p.A.), consisting of a full size aeroengine gearbox. Healthy and variously damaged bearings, such as with an inner or rolling element fault, are set up and vibration signals are collected and processed in order to properly detect a fault. Finally, data collected from a test rig assembled by the Dynamics & Identification Research Group (DIRG) are used to demonstrate that the proposed method is able to correctly detect and to classify different levels of the same type of fault and also to localise it.

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

    SciTech Connect

    Allen, D.; Helms, K.; Lagoudas, D.

    1995-08-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  12. Geometric evolution law for modeling strongly anisotropic thin-film morphology.

    PubMed

    Ograin, Christopher; Lowengrub, John

    2011-12-01

    The morphology of the solid-vapor interface of a nanoscale thin crystalline film is influenced by many factors including surface diffusion, attachment-detachment, deposition, and interface kinetics. Using a high-order accurate and efficient numerical method, we investigate the dynamics of two dimensional thin films when all of these effects are considered. The observed morphologies consist of facets of constant slope separated by narrow transition intervals: kinks (valleys) and antikinks (hills). The number of kinks and antikinks decreases as the system coarsens in time. Our numerical results confirm that when deposition is present, the only possible coarsening event is the kink-ternary where two kinks meet and annihilate an antikink. We characterize the total amount of coarsening, the time over which the coarsening occurs and the associated coarsening scaling laws when all effects are considered. As found in previous work that considered only attachment-detachment, or surface diffusion, there are three distinct coarsening regimes associated with increasing magnitudes of the deposition flux-fast coarsening, a regime in which periodic structures form with little or no subsequent coarsening, and a regime in which the film surface evolves chaotically. We find that the inclusion of attachment-detachment leads to additional coarsening compared to the dynamics that result from driven surface diffusion alone. When deposition and interface kinetics are both considered, the slowdown of evolution caused by the kinetic effects necessitates a decrease in the deposition flux in order to produce a nonchaotic coarsening regime. Together, these provide testable predictions for experiments of thin-film dynamics.

  13. Damage Evolution in Composite Materials and Sandwich Structures Under Impulse Loading

    NASA Astrophysics Data System (ADS)

    Silva, Michael Lee

    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

  14. Self-consistent evolution of tissue damage under stress wave propagation

    SciTech Connect

    Amendt, P; Glinsky, M; Kaufman, Y; London, R A; Sapir, M; Strauss, M

    1999-01-14

    Laser-initiated stress waves are reflected from tissue boundaries, thereby inducing tensile stresses, which are responsible for tissue damage. A self-consistent model of tissue failure evolution induced by stress wave propagation is considered. The failed tissue is represented by an ensemble of spherical voids and includes the effect of nucleation, growth and coalescence of voids under stress wave tension. Voids nucleate around impurities and grow according to an extended Rayleigh model that includes the effects of surface tension, viscosity and acoustic emission at void collapse. The damage model is coupled self-consistently to a one-dimensional planar hydrodynamic model of stress waves generated by a short pulse laser. We considered the problem of a bipolar wave generated by a short pulse laser absorbed on a free boundary of an aqueous system. The propagating wave includes a tensile component, which interacts with the impurities of exponential distribution in dimension, impurity density ({approximately}10{sup 8} cm{sup -3}) void and an ensemble of voids is generated. For moderate growth reduces the tensile wave component and causes the pressure to oscillate between tension and compression. For low impurity density ({approximately}10{sup 6} cm{sup -3} ) the bubbles grow on a long time scale (5-10 {micro}sec) relative to the wave interaction time ({approximately}100 nsec). At later times the growing bubbles interact with each other causing pressure oscillations and delay the system from reaching the 1 bar ambient compression pressure. This effect increases considerably the bubble lifetime consistent with experiments. At the collapse stage small bubbles collapse earlier and induce pressures, which reduce the collapse time of the larger bubbles.

  15. Fatigue crack initiation and damage evolution of unnotched titanium matrix composites

    NASA Astrophysics Data System (ADS)

    Her, Yung-Chiun

    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. Growth behavior of small fatigue cracks in TMCs was also studied carefully. It was found that fatigue crack initiation and multiplication of TMCs are strongly influenced by the thickness of the interfacial reaction layer. Fatigue crack will not develop from the micro-notches in the interfacial reaction layer until the thickness of the reaction layer exceeds a critical value. Matrix crack growth rate is affected by the applied stress level, however, it appears to be independent of the matrix material and heat treatment. The combined effects of fatigue crack multiplication and propagation result in stiffness degradation of the composites. The Ag/Ta duplex fiber coating significantly improves the transverse tensile and flexural creep resistance of the SCS-6/Ti-25-10 composite. However, the Ag/Ta-coated composite exhibits a shorter crack initiation life, higher number of matrix cracks, and higher crack growth rate than the uncoated composite. The embrittlement of the residual Ag/Ta layer suggests that Ag is not an effective diffusion barrier to prevent the interdiffusion of atomic species across the interface. The high interfacial cracking density and high interfacial bond strength in the Ag/Ta-coated SCS-6/Tisb3Al composite are believed to be responsible for its poor fatigue damage tolerance. For titanium alloys, the threshold intensity factor range, Delta Ksbth, for small fatigue cracks in the matrix alloys of TMCs has been determined to be between 0.9 ˜ 1.0 MPa*msp{1/2} which is much lower than that for long

  16. The Effects of Plasticity and the Evolution of Damage Zones in Earthquake Cycle Simulations

    NASA Astrophysics Data System (ADS)

    Erickson, B. A.; Dunham, E. M.

    2015-12-01

    How does plastic response during the earthquake cycle affect nucleation and propagation during individual events and the recurrence intervals between events? How do damage zones evolve with increasing cumulative slip and how do they affect subsequent rupture? To explore these questions we are developing a robust, physics-based earthquake cycle model accounting for off-fault yielding over multiple event sequences. The method is developed for the anti-plane framework where interseismic loading is imposed at the remote boundary. Spontaneous, quasi-dynamic events nucleate at the fault governed by rate-and-state friction. The off-fault volume is discretized with finite difference methods and time-dependent boundary conditions impose the free surface, remote loading and friction law at the fault. Stresses in the domain are limited by a Drucker-Prager yield condition, with depth-dependent normal stresses that remain constant in time during antiplane shear deformation. The constitutive theory furnishes a nonlinear equilibrium equation that makes use of an elastoplastic tangent stiffness tensor. One of the difficulties arising in our application problems is that plasticity reduces the effective shear modulus to values approaching zero and the equilibrium equations undergo a loss of solvability. One possible solution to this is through the incorporation of hardening which can provide a lower bound (away from zero) of the shear modulus. We assume zero initial plastic strain prior to the first event which nucleates down dip near a locking depth of 12 km. Plastic flow ensues when stresses exceed the yield condition. The event ruptures up dip with reduced rupture speed and slip velocity compared to its elastic counterpart, generating a flowerlike plastic strain distribution corresponding to greater damage near Earth's free surface. Our preliminary exploration of parameter space show that once the first event terminates, an interseismic loading period follows during which no

  17. The discrepancies in multistep damage evolution of yttria-stabilized zirconia irradiated with different ions

    SciTech Connect

    Yang, Tengfei; Taylor, Caitlin A.; Kong, Shuyan; Wang, Chenxu; Zhang, Yanwen; Huang, Xuejun; Xue, Jianming; Yan, Sha; Wang, Yugang

    2013-01-01

    This paper reports a comprehensive investigation of structural damage in yttria-stabilized zirconia irradiated with different ions over a wide fluence range. A similar multistep damage accumulation exists for the irradiations of different ions, but the critical doses for occurrence of second damage step, characterized by a faster increase in damage fraction, and the maximum elastic strain at the first damage step are varied and depend on ion mass. For irradiations of heavier ions, the second damage step occurs at a higher dose with a lower critical elastic strain. Furthermore, larger extended defects were observed in the irradiations of heavy ions at the second damage step. Associated with other experiment results and multistep damage accumulation model, the distinct discrepancies in the damage buildup under irradiations of different ions were interpreted by the effects of electronic excitation, energy of primary knock-on atom and chemistry contributions of deposited ions.

  18. Power-law spectrum and small-world structure emerge from coupled evolution of neuronal activity and synaptic dynamics

    NASA Astrophysics Data System (ADS)

    Zeng, Hong-Li; Zhu, Chen-Ping; Guo, Yan-Dong; Teng, Ao; Jia, Jing; Kong, Hui; Zhou, Rui; Yang, Juan-Ping; Li, Su-Quan

    2015-04-01

    A co-evolutionary neuronal network model based on previous ones is proposed, and both functional and structural properties are numerically calculated. Recent experiments have revealed power-law behavior in electrocorticogram (ECoG) spectrum related with synaptic plasticity and reorganization. In the present neuronal network model, the network starts its evolution from the initial configuration of random network which is the least biased and without special structure, and the interaction rules among neurons are modified from both models by Bornholdt's and Arcangelis' groups to simulate the process of synaptic development and maturation. The system exhibits dynamic small-world structure which is the result of evolution instead of the assumption beforehand. Meanwhile, the power spectrum of electrical signals reproduces the power-law behavior with the exponent 2.0 just as what is experimentally measured in ECoG spectrum. Moreover, the power spectrum of the average degree per neuron over time also exhibits power-law behavior, with the exponent 2.0 again over more than 5 orders of magnitude. Different from previous results, our network exhibits assortative degree-degree correlation which is expected to be checked by experiments.

  19. The co-evolution of microstructure features in self-ion irradiated HT9 at very high damage levels

    NASA Astrophysics Data System (ADS)

    Getto, E.; Vancoevering, G.; Was, G. S.

    2017-02-01

    Understanding the void swelling and phase evolution of reactor structural materials at very high damage levels is essential to maintaining safety and longevity of components in Gen IV fast reactors. A combination of ion irradiation and modeling was utilized to understand the microstructure evolution of ferritic-martensitic alloy HT9 at high dpa. Self-ion irradiation experiments were performed on alloy HT9 to determine the co-evolution of voids, dislocations and precipitates up to 650 dpa at 460 °C. Modeling of microstructure evolution was conducted using the modified Radiation Induced Microstructure Evolution (RIME) model, which utilizes a mean field rate theory approach with grouped cluster dynamics. Irradiations were performed with 5 MeV raster-scanned Fe2+ ions on samples pre-implanted with 10 atom parts per million He. The swelling, dislocation and precipitate evolution at very high dpa was determined using Analytical Electron Microscopy in Scanning Transmission Electron Microscopy (STEM) mode. Experimental results were then interpreted using the RIME model. A microstructure consisting only of dislocations and voids is insufficient to account for the swelling evolution observed experimentally at high damage levels in a complicated microstructure such as irradiated alloy HT9. G phase was found to have a minimal effect on either void or dislocation evolution. M2X played two roles; a variable biased sink for defects, and as a vehicle for removal of carbon from solution, thus promoting void growth. When accounting for all microstructure interactions, swelling at high damage levels is a dynamic process that continues to respond to other changes in the microstructure as long as they occur. effect of dislocations on voids, effect of precipitates on dislocations and voids and combined effect of dislocations and precipitates on voids. The overall approach will be to examine a simple system of voids and dislocations and then incorporate the more complex treatments of

  20. Features in chemical kinetics. I. Signatures of self-emerging dimensional reduction from a general format of the evolution law.

    PubMed

    Nicolini, Paolo; Frezzato, Diego

    2013-06-21

    Simplification of chemical kinetics description through dimensional reduction is particularly important to achieve an accurate numerical treatment of complex reacting systems, especially when stiff kinetics are considered and a comprehensive picture of the evolving system is required. To this aim several tools have been proposed in the past decades, such as sensitivity analysis, lumping approaches, and exploitation of time scales separation. In addition, there are methods based on the existence of the so-called slow manifolds, which are hyper-surfaces of lower dimension than the one of the whole phase-space and in whose neighborhood the slow evolution occurs after an initial fast transient. On the other hand, all tools contain to some extent a degree of subjectivity which seems to be irremovable. With reference to macroscopic and spatially homogeneous reacting systems under isothermal conditions, in this work we shall adopt a phenomenological approach to let self-emerge the dimensional reduction from the mathematical structure of the evolution law. By transforming the original system of polynomial differential equations, which describes the chemical evolution, into a universal quadratic format, and making a direct inspection of the high-order time-derivatives of the new dynamic variables, we then formulate a conjecture which leads to the concept of an "attractiveness" region in the phase-space where a well-defined state-dependent rate function ω has the simple evolution ω[over dot]=-ω(2) along any trajectory up to the stationary state. This constitutes, by itself, a drastic dimensional reduction from a system of N-dimensional equations (being N the number of chemical species) to a one-dimensional and universal evolution law for such a characteristic rate. Step-by-step numerical inspections on model kinetic schemes are presented. In the companion paper [P. Nicolini and D. Frezzato, J. Chem. Phys. 138, 234102 (2013)] this outcome will be naturally related to the

  1. Features in chemical kinetics. I. Signatures of self-emerging dimensional reduction from a general format of the evolution law

    NASA Astrophysics Data System (ADS)

    Nicolini, Paolo; Frezzato, Diego

    2013-06-01

    Simplification of chemical kinetics description through dimensional reduction is particularly important to achieve an accurate numerical treatment of complex reacting systems, especially when stiff kinetics are considered and a comprehensive picture of the evolving system is required. To this aim several tools have been proposed in the past decades, such as sensitivity analysis, lumping approaches, and exploitation of time scales separation. In addition, there are methods based on the existence of the so-called slow manifolds, which are hyper-surfaces of lower dimension than the one of the whole phase-space and in whose neighborhood the slow evolution occurs after an initial fast transient. On the other hand, all tools contain to some extent a degree of subjectivity which seems to be irremovable. With reference to macroscopic and spatially homogeneous reacting systems under isothermal conditions, in this work we shall adopt a phenomenological approach to let self-emerge the dimensional reduction from the mathematical structure of the evolution law. By transforming the original system of polynomial differential equations, which describes the chemical evolution, into a universal quadratic format, and making a direct inspection of the high-order time-derivatives of the new dynamic variables, we then formulate a conjecture which leads to the concept of an "attractiveness" region in the phase-space where a well-defined state-dependent rate function ω has the simple evolution dot{ω }= - ω ^2 along any trajectory up to the stationary state. This constitutes, by itself, a drastic dimensional reduction from a system of N-dimensional equations (being N the number of chemical species) to a one-dimensional and universal evolution law for such a characteristic rate. Step-by-step numerical inspections on model kinetic schemes are presented. In the companion paper [P. Nicolini and D. Frezzato, J. Chem. Phys. 138, 234102 (2013)], 10.1063/1.4809593 this outcome will be naturally

  2. US-Europe Workshop on Impact of Multifunctionality on Damage Evolution in Composite Materials

    DTIC Science & Technology

    2015-09-01

    fibers, with no degradation of inherent fracture properties. The vascular architecture is critical for in situ mixing, polymerization, and repeated...healing of delamination damage. An interpenetrating vascular network results in full recovery (>100%) of fracture resistance after delamination...impact damage, notch-tip splitting and fibre fracture accumulation are presented. US-EUROPE WORKSHOP ON IMPACT OF MULTIFUNCTIONALITY ON DAMAGE

  3. A methodology for determining the evolution law of gob permeability and its distributions in longwall coal mines

    NASA Astrophysics Data System (ADS)

    Zhang, Cun; Tu, Shihao; Zhang, Lei; Bai, Qingsheng; Yuan, Yong; Wang, Fangtian

    2016-04-01

    In order to understand the permeability evolution law of the gob by mining disturbances and obtain the permeability distribution of the fully compacted gob, comprehensive methods including theoretical analyses of monitoring data and numerical simulation are used to determine the permeability of gobs in the mining process. Based on current research, three zones of the vertical stress and permeability in the gob are introduced in this article, which are the caving rock mass accumulation zone, the gradually compacted zone and the fully compacted zone. A simple algorithm is written by using FISH language to be imported into the reservoir model. FISH language is an internal programming language in FLAC3D. It is possible to calculate the permeability at each zone with this algorithm in the mining process. Besides, we analyze the gas flow rates from seven gob gas ventholes (GGV) located on a longwall face operated in a mine of a Huainan coalfield in Huainan City, China. Combined with Darcy’s law, a calculation model of permeability around GGV in the gob is proposed. Using this model, the evolution law of permeability in the gob is deduced; the phases of permeability evolution are the decline stage and the stable stage. The result of the vertical stress monitoring data and good fitting effect of the permeability to the experimental data show that the permeability decline caused by the compaction of the gob is the principal reason for the decline stage. The stable stage indicates that the gob has been fully compacted, and the average period of full gob compaction is 47.75 d. The permeability in the middle of the compacted gob is much smaller than the permeability on the edge of the gob which presents an O shape trend. Besides, the little difference among the results of the numerical simulation, the permeability calculation model and other commonly used calculation models validate the correctness of the permeability calculation model and numerical simulation results.

  4. Padova Charter on personal injury and damage under civil-tort law : Medico-legal guidelines on methods of ascertainment and criteria of evaluation.

    PubMed

    Ferrara, Santo Davide; Baccino, Eric; Boscolo-Berto, Rafael; Comandè, Giovanni; Domenici, Ranieri; Hernandez-Cueto, Claudio; Gulmen, Mete Korkut; Mendelson, George; Montisci, Massimo; Norelli, Gian Aristide; Pinchi, Vilma; Ranavaya, Mohammed; Shokry, Dina A; Sterzik, Vera; Vermylen, Yvo; Vieira, Duarte Nuno; Viel, Guido; Zoja, Riccardo

    2016-01-01

    Compensation for personal damage, defined as any pecuniary or non-pecuniary loss causally related to a personal injury under civil-tort law, is strictly based on the local jurisdiction and therefore varies significantly across the world. This manuscript presents the first "International Guidelines on Medico-Legal Methods of Ascertainment and Criteria of Evaluation of Personal Injury and Damage under Civil-Tort Law". This consensus document, which includes a step-by-step illustrated explanation of flow charts articulated in eight sequential steps and a comprehensive description of the ascertainment methodology and the criteria of evaluation, has been developed by an International Working Group composed of juridical and medico-legal experts and adopted as Guidelines by the International Academy of Legal Medicine (IALM).

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

    NASA Astrophysics Data System (ADS)

    Freire, Igor Leite; Santos Sampaio, Júlio Cesar

    2014-02-01

    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.

  6. Estimation of the Past and Future Infrastructure Damage Due the Permafrost Evolution Processes

    NASA Astrophysics Data System (ADS)

    Sergeev, D. O.; Chesnokova, I. V.; Morozova, A. V.

    2015-12-01

    The geocryological processes such as thermokarst, frost heaving and fracturing, icing, thermal erosion are the source of immediate danger for the structures. The economic losses during the construction procedures in the permafrost area are linked also with the other geological processes that have the specific character in cold regions. These processes are swamping, desertification, deflation, flooding, mudflows and landslides. Linear transport structures are most vulnerable component of regional and national economy. Because the high length the transport structures have to cross the landscapes with different permafrost conditions that have the different reaction to climate change. The climate warming is favorable for thermokarst and the frost heaving is linked with climate cooling. In result the structure falls in the circumstances that are not predicted in the construction project. Local engineering problems of structure exploitation lead to global risks of sustainable development of regions. Authors developed the database of geocryological damage cases for the last twelve years at the Russian territory. Spatial data have the attributive table that was filled by the published information from various permafrost conference proceedings. The preliminary GIS-analysis of gathered data showed the widespread territorial distribution of the cases of negative consequences of geocryological processes activity. The information about maximum effect from geocryological processes was validated by detailed field investigation along the railways in Yamal and Transbaicalia Regions. Authors expect the expanding of database by similar data from other sectors of Arctic. It is important for analyzing the regional, time and industrial tendencies of geocryological risk evolution. Obtained information could be used in insurance procedures and in information systems of decisions support in different management levels. The investigation was completed with financial support by Russian

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

    PubMed

    Madrazo, Alejandro

    2009-09-01

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

  8. Low velocity impact response and damage evolution in unreinforced resin systems and self-repairing polymer matrix composites

    NASA Astrophysics Data System (ADS)

    Motuku, Molefi

    The low velocity impact response and damage evolution in unreinforced polymer matrices, conventional polymer matrix composites, and self-repairing polymer matrix composites was investigated. The impact response study of unreinforced matrices and conventional laminates was undertaken because the failure initiation energies, threshold energy levels, failure characteristics and damage evolution in both the matrix material (unreinforced resin plaques) and the composite are intrinsic to proper design of a self-repairing composite. The self-repairing concept was investigated due to its attractive potential to alleviate damage problems in polymer matrix composites. Self-repairing composites, which fall under the category of passive smart polymer composites, have the potential to self repair both micro- and macro-damage resulting from impacts as well as non-impact loading. The self-repairing mechanism is achieved through the incorporation of hollow fibers in addition to the normal solid reinforcing fibers. The hollow fibers store the damage-repairing solution or chemicals that are released into the matrix or damaged zone upon fiber failure to repair and/or arrest damage progression. The room temperature low velocity impact response and damage evolution in DERAKANE 411-350 and 411-C50 vinyl ester unreinforced resin systems was investigated as a function of impact energy level, sample thickness, matrix material and catalyst system. The low velocity impact response of conventional and self-repairing glass reinforced polymer composites was investigated by addressing the fabrication and some of the parameters that influence their response to low velocity impact loading. Specific issues addressed by this study include developing a process to fabricate self-repairing laminates, processing quality; selection of storage material for the repairing solution; release and transportation of repairing solution; the effect of the number, type and spatial distribution of the repairing

  9. Limitations on the Evolution of Quantum Coherences: Towards Fully Quantum Second Laws of Thermodynamics.

    PubMed

    Ćwikliński, Piotr; Studziński, Michał; Horodecki, Michał; Oppenheim, Jonathan

    2015-11-20

    The second law of thermodynamics places a limitation into which states a system can evolve into. For systems in contact with a heat bath, it can be combined with the law of energy conservation, and it says that a system can only evolve into another if the free energy goes down. Recently, it's been shown that there are actually many second laws, and that it is only for large macroscopic systems that they all become equivalent to the ordinary one. These additional second laws also hold for quantum systems, and are, in fact, often more relevant in this regime. They place a restriction on how the probabilities of energy levels can evolve. Here, we consider additional restrictions on how the coherences between energy levels can evolve. Coherences can only go down, and we provide a set of restrictions which limit the extent to which they can be maintained. We find that coherences over energy levels must decay at rates that are suitably adapted to the transition rates between energy levels. We show that the limitations are matched in the case of a single qubit, in which case we obtain the full characterization of state-to-state transformations. For higher dimensions, we conjecture that more severe constraints exist. We also introduce a new class of thermodynamical operations which allow for greater manipulation of coherences and study its power with respect to a class of operations known as thermal operations.

  10. Molecular dynamics study of radiation damage and microstructure evolution of zigzag single-walled carbon nanotubes under carbon ion incidence

    NASA Astrophysics Data System (ADS)

    Li, Huan; Tang, Xiaobin; Chen, Feida; Huang, Hai; Liu, Jian; Chen, Da

    2016-07-01

    The radiation damage and microstructure evolution of different zigzag single-walled carbon nanotubes (SWCNTs) were investigated under incident carbon ion by molecular dynamics (MD) simulations. The radiation damage of SWCNTs under incident carbon ion with energy ranging from 25 eV to 1 keV at 300 K showed many differences at different incident sites, and the defect production increased to the maximum value with the increase in incident ion energy, and slightly decreased but stayed fairly stable within the majority of the energy range. The maximum damage of SWCNTs appeared when the incident ion energy reached 200 eV and the level of damage was directly proportional to incident ion fluence. The radiation damage was also studied at 100 K and 700 K and the defect production decreased distinctly with rising temperature because radiation-induced defects would anneal and recombine by saturating dangling bonds and reconstructing carbon network at the higher temperature. Furthermore, the stability of a large-diameter tube surpassed that of a thin one under the same radiation environments.

  11. Strain-dependent Damage Evolution and Velocity Reduction in Fault Zones Induced by Earthquake Rupture

    NASA Astrophysics Data System (ADS)

    Zhong, J.; Duan, B.

    2009-12-01

    Low-velocity fault zones (LVFZs) with reduced seismic velocities relative to the surrounding wall rocks are widely observed around active faults. The presence of such a zone will affect rupture propagation, near-field ground motion, and off-fault damage in subsequent earth-quakes. In this study, we quantify the reduction of seismic velocities caused by dynamic rup-ture on a 2D planar fault surrounded by a low-velocity fault zone. First, we implement the damage rheology (Lyakhovsky et al. 1997) in EQdyna (Duan and Oglesby 2006), an explicit dynamic finite element code. We further extend this damage rheology model to include the dependence of strains on crack density. Then, we quantify off-fault continuum damage distribution and velocity reduction induced by earthquake rupture with the presence of a preexisting LVFZ. We find that the presence of a LVFZ affects the tempo-spatial distribu-tions of off-fault damage. Because lack of constraint in some damage parameters, we further investigate the relationship between velocity reduction and these damage prameters by a large suite of numerical simulations. Slip velocity, slip, and near-field ground motions computed from damage rheology are also compared with those from off-fault elastic or elastoplastic responses. We find that the reduction in elastic moduli during dynamic rupture has profound impact on these quantities.

  12. The evolution of the american law institute test for insanity in Oregon: focus on diagnosis.

    PubMed

    Lockey, Christopher J; Bloom, Joseph D

    2007-01-01

    In 1962, the American Law Institute published its Model Penal Code, which includes an insanity test later adopted by many states. The second paragraph of the test excludes people with certain psychiatric conditions manifested by repeated criminal or antisocial conduct from using them as a basis for an insanity defense. Oregon adopted this test in 1971. Since then, its legislature and courts have added to the conditions excluded in the second paragraph. In this article, we look at how recent Oregon appellate court decisions have culminated in a narrower and less contentious notion of which psychiatric diagnoses serve as a basis for an insanity defense. Then we discuss Oregon's expansion of the second paragraph of the American Law Institute Insanity Test in a national context.

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

    SciTech Connect

    Wang, P.C.; Jeng, S.M.; Yang, J.M.; Russ, S.M.

    1996-08-01

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

  14. Space Law

    NASA Astrophysics Data System (ADS)

    Hermida, Julian

    2006-01-01

    This chapter examines the salient characteristics of Space Law. It analyzes the origins and evolution of Space Law, its main international principles, and some current topics of interest to the scientific community: the delimitation of airspace and outer space, intellectual property, and criminal responsibility.

  15. Numerical simulation of the damage evolution in the pelvic floor muscles during childbirth.

    PubMed

    Oliveira, Dulce A; Parente, Marco P L; Calvo, Begoña; Mascarenhas, Teresa; Natal Jorge, Renato M

    2016-02-29

    Several studies have shown that pelvic floor injuries during a vaginal delivery can be considered a significant factor in the development of pelvic floor dysfunction. Such disorders include a group of conditions affecting women like urinary incontinence, pelvic organ prolapse and fecal incontinence. Numerical simulations are valuable tools that are contributing to the clarification of the mechanisms behind pelvic floor disorders. The aim of this work is to propose a mechanical model implemented in the finite element method context to estimate the damage in the pelvic floor muscles by mechanical effects during a vaginal delivery of a fetus in vertex presentation and occipitoanterior position. The constitutive model adopted has already been successfully used in the simulation of childbirth and the structural damage model added has previously been applied to characterize the damage process in biological soft tissues undergoing finite deformations. The constitutive parameters were fit to experimental data available in the literature and the final proposed material model is suitable to estimate the mechanical damage in the pelvic floor muscle during a vaginal delivery. The computational model predicts that even an apparently uneventful vaginal delivery inflicts injuries to the pelvic floor muscles, particularly during the extension of the fetus head, having been obtained more than 10% of damaged fibers. As a clinical evidence, the present work allows to conclude that the puborectalis component of the levator ani muscle is the most prone to damage.

  16. Tracking composite material damage evolution using Bayesian filtering and flash thermography data

    NASA Astrophysics Data System (ADS)

    Gregory, Elizabeth D.; Holland, Steve D.

    2016-05-01

    We propose a method for tracking the condition of a composite part using Bayesian filtering of ash thermography data over the lifetime of the part. In this demonstration, composite panels were fabricated; impacted to induce subsurface delaminations; and loaded in compression over multiple time steps, causing the delaminations to grow in size. Flash thermography data was collected between each damage event to serve as a time history of the part. The ash thermography indicated some areas of damage but provided little additional information as to the exact nature or depth of the damage. Computed tomography (CT) data was also collected after each damage event and provided a high resolution volume model of damage that acted as truth. After each cycle, the condition estimate, from the ash thermography data and the Bayesian filter, was compared to 'ground truth'. The Bayesian process builds on the lifetime history of ash thermography scans and can give better estimates of material condition as compared to the most recent scan alone, which is common practice in the aerospace industry. Bayesian inference provides probabilistic estimates of damage condition that are updated as each new set of data becomes available. The method was tested on simulated data and then on an experimental data set.

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

    SciTech Connect

    Hoelzer, M.A.; Michod, R.E. )

    1991-06-01

    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.

  18. In-situ X-ray CT results of damage evolution in L6 ordinary chondrite meteorites

    SciTech Connect

    Cuadra, Jefferson A.; Hazeli, Kavan; Ramesh, K. T.; Martz, Harry

    2016-06-17

    These are slides about in-situ X-ray CT results of damage evolution in L6 ordinary chondrite meteorites. The following topics are covered: mechanical and thermal damage characterization, list of Grosvenor Mountain (GRO) meteorite samples, in-situ x-ray compression test setup, GRO-chipped reference at 0 N - existing cracks, GRO-chipped loaded at 1580 N, in-situ x-ray thermal fatigue test setup, GRO-B14 room temperature reference, GRO-B14 Cycle 47 at 200°C, GRO-B14 Cycle 47 at room temperature, conclusions from qualitative analysis, future work and next steps. Conclusions are the following: Both GRO-Chipped and GRO-B14 had existing voids and cracks within the volume. These sites with existing damage were selected for CT images from mechanically and thermally loaded scans since they are prone to damage initiation. The GRO-Chipped sample was loaded to 1580 N which resulted in a 14% compressive engineering strain, calculated using LVDT. Based on the CT cross sectional images, the GRO-B14 sample at 200°C has a thermal expansion of approximately 96 μm in height (i.e. ~1.6% engineering strain).

  19. Effect of Heat Input on the Tensile Damage Evolution in Pulsed Laser Welded Ti6Al4V Titanium Sheets

    NASA Astrophysics Data System (ADS)

    Liu, Jing; Gao, Xiaolong; Zhang, Jianxun

    2016-11-01

    The present paper is focused on studying the effect of heat input on the tensile damage evolution of pulsed Nd:YAG laser welding of Ti6Al4V alloy under monotonic loading. To analyze the reasons that the tensile fracture site of the pulsed-laser-welded Ti6Al4V sheet joints changes with the heat input under monotonic loading, the microstructure of the sample with different nominal strain values was investigated by in situ observation. Experiment results show that the tensile ductility and fatigue life of welded joints with low heat input are higher than that of welded joints with high heat input. Under tensile loads, the critical engineering strain for crack initiation is much lower in the welded joint with high heat input than in the welded joints with low and medium heat input. And the microstructural damage accumulation is much faster in the fusion zone than in the base metal for the welded joints with high input, whereas the microstructural damage accumulation is much faster in the base metal than in the fusion zone for the welded joints with low input. Consequently, the welded joints fractured in the fusion zone for the welds with high heat input, whereas the welded joints ruptured in the base metal for the welds with low heat input. It is proved that the fine grain microstructure produced by low heat input can improve the critical nominal strain for crack initiation and the resistance ability of microstructural damage.

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

    NASA Astrophysics Data System (ADS)

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

    2011-07-01

    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.

  1. Cavity evolution at grain boundaries as a function of radiation damage and thermal conditions in nanocrystalline nickel

    SciTech Connect

    Muntifering, Brittany; Blair, Sarah Jane; Gong, Cajer; Dunn, Aaron; Dingreville, Remi; Qu, Jianmin; Hattar, Khalid

    2015-12-30

    Enhanced radiation tolerance of nanostructured metals is attributed to the high density of interfaces that can absorb radiation-induced defects. Here, cavity evolution mechanisms during cascade damage, helium implantation, and annealing of nanocrystalline nickel are characterized via in situ transmission electron microscopy (TEM). Films subjected to self-ion irradiation followed by helium implantation developed evenly distributed cavity structures, whereas films exposed in the reversed order developed cavities preferentially distributed along grain boundaries. Post-irradiation annealing and orientation mapping demonstrated uniform cavity growth in the nanocrystalline structure, and cavities spanning multiple grains. Furthermore, these mechanisms suggest limited ability to reduce swelling, despite the stability of the nanostructure.

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

    NASA Astrophysics Data System (ADS)

    Soesoo, Alvar; Bons, Paul D.

    2015-07-01

    Magma is generated by partial melting from micrometre-scale droplets at the source and may accumulate to form >100 km-scale plutons. Magma accumulation thus spans well over ten orders of magnitude in scale. Here we provide measurements of migmatitic leucosomes and granitic veins in drill cores from the Estonian Proterozoic basement and outcrops at Masku in SW Finland and Montemor-o-Novo, central Portugal. Despite the differences in size and number of measured leucosomes and magmatic veins, differences in host rock types and metamorphic grades, the cumulative width distribution of the studied magmatic leucosomes/veins follows a power law with exponents usually between 0.7 and 1.8. Published maps of the SE Australian Lachlan Fold Belt were used to investigate the distribution of granitoid pluton sizes. The granites occupy ca. 22 % of the 2.6 × 105 km2 area. The cumulative pluton area distributions show good power law distributions with exponents between 0.6 and 0.8 depending on pluton area group. Using the self-affine nature of pluton shapes, it is possible to estimate the total volume of magma that was expelled from the source in the 2.6 × 105 km2 map area, giving an estimated 0.8 km3 of magma per km2. It has been suggested in the literature that magma batches in the source merge to form ever-bigger batches in a self-organized way. This leads to a power law for the cumulative distribution of magma volumes, with an exponent m V between 1 for inefficient melt extraction, and 2/3 for maximum accumulation efficiency as most of the volume resides in the largest batches that can escape from the source. If m V ≥ 1, the mass of the magma is dominated by small batches; in case m = 2/3, about 50 % of all magma in the system is placed in a single largest batch. Our observations support the model that the crust develops a self-organized critical state during magma generation. In this state, magma batches accumulate in a non-continuous, step-wise manner to form ever

  3. Comparing monofractal and multifractal analysis of corrosion damage evolution in reinforcing bars.

    PubMed

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

    2012-01-01

    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.

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

    PubMed Central

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

    2012-01-01

    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. PMID:22238682

  5. Collateral damage: rapid exposure-induced evolution of pesticide resistance leads to increased susceptibility to parasites.

    PubMed

    Jansen, Mieke; Stoks, Robby; Coors, Anja; van Doorslaer, Wendy; de Meester, Luc

    2011-09-01

    Although natural populations may evolve resistance to anthropogenic stressors such as pollutants, this evolved resistance may carry costs. Using an experimental evolution approach, we exposed different Daphnia magna populations in outdoor containers to the carbamate pesticide carbaryl and control conditions, and assessed the resulting populations for both their resistance to carbaryl as well as their susceptibility to infection by the widespread bacterial microparasite Pasteuria ramosa. Our results show that carbaryl selection led to rapid evolution of carbaryl resistance with seemingly no cost when assessed in a benign environment. However, carbaryl-resistant populations were more susceptible to parasite infection than control populations. Exposure to both stressors reveals a synergistic effect on sterilization rate by P. ramosa, but this synergism did not evolve under pesticide selection. Assessing costs of rapid adaptive evolution to anthropogenic stress in a semi-natural context may be crucial to avoid too optimistic predictions for the fitness of the evolving populations.

  6. Theoretical predicting of permeability evolution in damaged rock under compressive stress

    NASA Astrophysics Data System (ADS)

    Vu, M. N.; Nguyen, S. T.; To, Q. D.; Dao, N. H.

    2017-03-01

    This paper outlines an analytical model of crack growth induced permeability changes. A theoretical solution of effective permeability of cracked porous media is derived. The fluid flow obeys Poisseuille's law along the crack and Darcy's law in the porous matrix. This solution exhibits a percolation threshold for any type of crack distribution apart from a parallel crack distribution. The physical behaviour of fluid flow through a cracked porous material is well reproduced by the proposed model. The presence of this effective permeability coupling to analytical expression of crack growth under compression enables the modelling of the permeability variation due to stress-induced cracking in a porous rock. This incorporation allows the prediction of the permeability change of a porous rock embedding an anisotropic crack distribution from any initial crack density, i.e. lower, around or upper to percolation threshold. The interaction between cracks is not explicitly taken into account. The model is well applicable both to micro and macro-cracks.

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

    PubMed

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

    2014-01-01

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

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

    PubMed

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

    2012-01-01

    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.

  9. Fatigue damage evolution study with non-destructive magnetic properties measurement method using scanning SQUID microscopy

    NASA Astrophysics Data System (ADS)

    Lee, Tae-Kyu

    The fatigue process can be precisely defined in the crack propagation stage, where the fatigue damage can be evaluated by observed cracks and where an increase of the dislocation density occurs at the first 10% of the fatigue life. But for the stages between dislocation saturation and prior to nucleation, no definition can be given due to the relative difficulty in quantifying the damage. Especially, detecting a high-cycle fatigue damage is a particularly important yet an unsolved problem in non-destructive testing. There are no reliable techniques to measure the progress of fatigue in the intermediate fatigue regime, the second stage of fatigue, where the overall dislocation density is approximately constant and the microstructural changes are subtle include about 80% of the fatigue life in high-cycle fatigue. In this study, a non-destructive evaluation method is established by continuously measuring the magnetic properties, which interact with the developing fatigue damage during cyclic loading. Dislocations and microcracks which are initiated during the fatigue act as pinning sites which impede the motion of magnetic domain walls under the applied magnetic field, thereby influencing the bulk magnetic properties. The remanence field of various fatigued steel specimens are detected using a scanning microscope based on a high transition temperature Superconducting Quantum Interference Device (SQUID). The results show the development of localized peaks in remanent magnetization prior to the formation of visible fatigue cracks. Even in the second stage of fatigue, where the macroscopic state of the sample is relatively constant, the results show that a scanning SQUID microscope is capable of detecting regions of fatigue damage both on surface and in sub-surface regions.

  10. Negative Power Law Scaling of Rockfalls along the Yorkshire Coast: Implications for Long Term Landscape Evolution

    NASA Astrophysics Data System (ADS)

    Barlow, John; Rosser, Nick; Lime, Michael; Petley, David; Brain, Matthew; Sapsford, Melanie; Norman, Emma

    2010-05-01

    An increasing body of evidence suggests that rockfalls follow a negative power law scaling in their magnitude-frequency distribution of the form F = aM-b. Where F is the normalized frequency density, M is the event magnitude, and a / b are dimensionless scaling coefficients. Investigation using Terrestrial Laser Scanning (TLS) has produced an extremely high resolution inventory of rockfall magnitudes along the sea cliffs near Staithes, UK. Such data is ideal for erosion modelling. Once the scaling parameters have been estimated, the volume of eroded rock for events of magnitude x (Vx) is derived as Vx = ax-b+1. Therefore, the total volume (V t) of eroded rock between a minimum and maximum magnitude can be calculated by taking by integrating the above. An examination of monthly fluctuations in the scaling coefficients indicates greater variation within the winter months in response to higher deliveries of wave energy during these months. Initial results using geophone data indicate a relationship between the magnitude of the scaling coefficients and the amount of wave energy delivered to the cliff. Such linkages suggest the possibility of a predictive model for erosion based on wave climate, providing a predictive capability for the implications of environmental change. Model testing is to be accomplished using an innovative cliff recession model derived using cosmogenic isotope concentrations and paleoenvironmental data. Our cosmogenic dating model considers marine variables (tidal range, wave climate and inundation duration); Holocene relative sea level change; lateral cliff retreat, and the consequent changes in geometrical and marine shielding to establish the rate of retreat based on a continuum of Be10 concentrations.

  11. Re-evolution of lost mandibular teeth in frogs after more than 200 million years, and re-evaluating Dollo's law.

    PubMed

    Wiens, John J

    2011-05-01

    Dollo's law states that structures that are evolutionarily lost will not be regained. Recent phylogenetic studies have revealed several potential examples in which Dollo's law seems to be violated, where lost structures appear to have been regained over evolutionary time. However, these examples have recently been questioned and suggested to be methodological artifacts. In this article, I document a striking and incontrovertible phylogenetic example of the re-evolution of a lost, complex structure: mandibular teeth in the frog genus Gastrotheca. I use a time-calibrated phylogeny for 170 amphibian species to show that mandibular teeth were lost in the ancestor of modern frogs at least 230 million years ago (Mya) and have been regained in the last ∼ 5-17 My. I review recent studies on trait re-evolution and show that this long period of trait absence prior to re-acquisition is largely unprecedented. I also argue that there are several methodological issues that may cause trait re-evolution to be hardest to detect under those conditions when it is most likely to occur, leading to erroneous failures to reject Dollo's law. Finally, I discuss a mechanism that may facilitate trait re-evolution, and the evolution of mandibular teeth in frogs as an example of developmental constraint.

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

    NASA Astrophysics Data System (ADS)

    Wu, Y.; Peroulis, D.

    2015-02-01

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

  13. Process compensated resonance testing modeling for damage evolution and uncertainty quantification

    NASA Astrophysics Data System (ADS)

    Biedermann, Eric; Heffernan, Julieanne; Mayes, Alexander; Gatewood, Garrett; Jauriqui, Leanne; Goodlet, Brent; Pollock, Tresa; Torbet, Chris; Aldrin, John C.; Mazdiyasni, Siamack

    2017-02-01

    Process Compensated Resonance Testing (PCRT) is a nondestructive evaluation (NDE) method based on the fundamentals of Resonant Ultrasound Spectroscopy (RUS). PCRT is used for material characterization, defect detection, process control and life monitoring of critical gas turbine engine and aircraft components. Forward modeling and model inversion for PCRT have the potential to greatly increase the method's material characterization capability while reducing its dependence on compiling a large population of physical resonance measurements. This paper presents progress on forward modeling studies for damage mechanisms and defects in common to structural materials for gas turbine engines. Finite element method (FEM) models of single crystal (SX) Ni-based superalloy Mar-M247 dog bones and Ti-6Al-4V cylindrical bars were created, and FEM modal analyses calculated the resonance frequencies for the samples in their baseline condition. Then the frequency effects of superalloy creep (high-temperature plastic deformation) and macroscopic texture (preferred crystallographic orientation of grains detrimental to fatigue properties) were evaluated. A PCRT sorting module for creep damage in Mar-M247 was trained with a virtual database made entirely of modeled design points. The sorting module demonstrated successful discrimination of design points with as little as 1% creep strain in the gauge section from a population of acceptable design points with a range of material and geometric variation. The resonance frequency effects of macro-scale texture in Ti-6Al-4V were quantified with forward models of cylinder samples. FEM-based model inversion was demonstrated for Mar-M247 bulk material properties and variations in crystallographic orientation. PCRT uncertainty quantification (UQ) was performed using Monte Carlo studies for Mar-M247 that quantified the overall uncertainty in resonance frequencies resulting from coupled variation in geometry, material properties, crystallographic

  14. Synergistic Effects of Frequency and Temperature on Damage Evolution and Life Prediction of Cross-Ply Ceramic Matrix Composites under Tension-Tension Fatigue Loading

    NASA Astrophysics Data System (ADS)

    Longbiao, Li

    2016-12-01

    In this paper, the synergistic effects of loading frequency and testing temperature on the fatigue damage evolution and life prediction of cross-ply SiC/MAS ceramic-matrix composite have been investigated. The damage parameters of the fatigue hysteresis modulus, fatigue hysteresis dissipated energy and the interface shear stress were used to monitor the damage evolution inside of SiC/MAS composite. The evolution of fatigue hysteresis dissipated energy, the interface shear stress and broken fibers fraction versus cycle number, and the fatigue life S-N curves of SiC/MAS composite under the loading frequency of 1 and 10 Hz at 566 °C and 1093 °C in air condition have been predicted. The synergistic effects of the loading frequency and testing temperature on the degradation rate of fatigue hysteresis dissipated energy and the interface shear stress have been analyzed.

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

    PubMed

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

    2009-05-29

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

  16. Civil Law Glossary.

    ERIC Educational Resources Information Center

    Update on Law-Related Education, 1997

    1997-01-01

    Presents a glossary of civil law terms originally compiled for journalists by the American Bar Association. Defines many essential civil law concepts and practices including compensatory damages, jurisdiction, motion to dismiss, discovery, and remedy. (MJP)

  17. Cavity evolution at grain boundaries as a function of radiation damage and thermal conditions in nanocrystalline nickel

    DOE PAGES

    Muntifering, Brittany; Blair, Sarah Jane; Gong, Cajer; ...

    2015-12-30

    Enhanced radiation tolerance of nanostructured metals is attributed to the high density of interfaces that can absorb radiation-induced defects. Here, cavity evolution mechanisms during cascade damage, helium implantation, and annealing of nanocrystalline nickel are characterized via in situ transmission electron microscopy (TEM). Films subjected to self-ion irradiation followed by helium implantation developed evenly distributed cavity structures, whereas films exposed in the reversed order developed cavities preferentially distributed along grain boundaries. Post-irradiation annealing and orientation mapping demonstrated uniform cavity growth in the nanocrystalline structure, and cavities spanning multiple grains. Furthermore, these mechanisms suggest limited ability to reduce swelling, despite the stabilitymore » of the nanostructure.« less

  18. The effects of shockwave profile shape and shock obliquity on spallation in Cu and Ta: kinetic and stress-state effects on damage evolution(u)

    SciTech Connect

    Gray, George T

    2010-12-14

    Widespread research over the past five decades has provided a wealth of experimental data and insight concerning shock hardening and the spallation response of materials subjected to square-topped shock-wave loading profiles. Less quantitative data have been gathered on the effect of direct, in-contact, high explosive (HE)-driven Taylor wave (or triangular-wave) loading profile shock loading on the shock hardening, damage evolution, or spallation response of materials. Explosive loading induces an impulse dubbed a 'Taylor Wave'. This is a significantly different loading history than that achieved by a square-topped impulse in terms of both the pulse duration at a fixed peak pressure, and a different unloading strain rate from the peak Hugoniot state achieved. The goal of this research is to quantify the influence of shockwave obliquity on the spallation response of copper and tantalum by subjecting plates of each material to HE-driven sweeping detonation-wave loading and quantify both the wave propagation and the post-mortem damage evolution. This talk will summarize our current understanding of damage evolution during sweeping detonation-wave spallation loading in Cu and Ta and show comparisons to modeling simulations. The spallation responses of Cu and Ta are both shown to be critically dependent on the shockwave profile and the stress-state of the shock. Based on variations in the specifics of the shock drive (pulse shape, peak stress, shock obliquity) and sample geometry in Cu and Ta, 'spall strength' varies by over a factor of two and the details of the mechanisms of the damage evolution is seen to vary. Simplistic models of spallation, such as P{sub min} based on 1-D square-top shock data lack the physics to capture the influence of kinetics on damage evolution such as that operative during sweeping detonation loading. Such considerations are important for the development of predictive models of damage evolution and spallation in metals and alloys.

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

    SciTech Connect

    Mourad, Hashem M; Bronkhorst, Curt A; Addessio, Francis L

    2010-12-16

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

  20. Strain Accumulation and Damage Evolution During Creep of SiCf/SiC Composites

    NASA Astrophysics Data System (ADS)

    Wilshire, Brian; Burt, Howard

    For many high-performance applications, worldwide research efforts continue to be focussed on ceramic-fibre-reinforced ceramic-matrix composites (CFCMCs), with numerous studies featuring SiC-fibre-reinforced SiC-matrix materials (termed SiCf/SiC type products). In particular, because these CFCMCs are being considered for components which must operate for long periods without failure under load in hostile high-temperature environments, special attention has then been directed to characterization of their creep and creep fracture behaviour. In turn, many of these studies have been concerned with clarification of the damage processes which cause creep failure, aiming to acquire the understanding needed for future product development and component design.

  1. Damage Evolution in Al Wire Bonds Subjected to a Junction Temperature Fluctuation of 30 K

    NASA Astrophysics Data System (ADS)

    Agyakwa, Pearl A.; Yang, Li; Arjmand, Elaheh; Evans, Paul; Corfield, Martin R.; Johnson, C. Mark

    2016-07-01

    Ultrasonically bonded heavy Al wires subjected to a small junction temperature fluctuation under power cycling from 40°C to 70°C were investigated using a non-destructive three-dimensional (3-D) x-ray tomography evaluation approach. The occurrence of irreversible deformation of the microstructure and wear-out under such conditions were demonstrated. The observed microstructures consist of interfacial and inter-granular cracks concentrated in zones of stress intensity, i.e., near heels and emanating from interface precracks. Interfacial voids were also observed within the bond interior. Degradation rates of `first' and `stitch' bonds are compared and contrasted. A correlative microscopy study combining perspectives from optical microscopy with the x-ray tomography results clarifies the damage observed. An estimation of lifetime is made from the results and discussed in the light of existing predictions.

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

    SciTech Connect

    Allen, D.H.; Hurtado, L.D.; Helms, K.L.E.

    1995-03-01

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

  3. Evolution.

    ERIC Educational Resources Information Center

    Mayr, Ernst

    1978-01-01

    Traces the history of evolution theory from Lamarck and Darwin to the present. Discusses natural selection in detail. Suggests that, besides biological evolution, there is also a cultural evolution which is more rapid than the former. (MA)

  4. Real time in-situ sensing of damage evolution in nanocomposite bonded surrogate energetic materials

    NASA Astrophysics Data System (ADS)

    Sengezer, Engin C.; Seidel, Gary D.

    2016-04-01

    The current work aims to explore the potential for in-situ structural health monitoring in polymer bonded energetic materials through the introduction of carbon nanotubes (CNTs) into the binder phase as a means to establish a significant piezoresistive response through the resulting nanocomposite binder. The experimental effort herein is focused towards electro-mechanical characterization of surrogate materials in place of actual energetic (explosive) materials in order to provide proof of concept for the strain and damage sensing. The electrical conductivity and the piezoresistive behavior of samples containing randomly oriented MWCNTs introduced into the epoxy (EPON 862) binder of 70 wt% ammonium perchlorate-epoxy hybrid composites are quantitatively and qualitatively evaluated. Brittle failure going through linear elastic behavior, formation of microcracks leading to reduction in composite load carrying capacity and finally macrocracks resulting in eventual failure are observed in the mechanical response of MWNT-ammonium perchlorateepoxy hybrid composites. Incorporating MWNTs into local polymer binder improves the effective stiffness about 40% compared to neat ammonium perchlorate-polymer samples. The real time in-situ relative change in resistance for MWNT hybrid composites was detected with the applied strains through piezoresistive response.

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

    SciTech Connect

    Barashev, Alexander V; Golubov, Stanislav I; Stoller, Roger E

    2012-06-01

    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.

  6. InSitu SEM Investigation of Microstructural Damage Evolution and Strain Relaxation in a Melt Infiltrated SiC/SiC Composite

    NASA Technical Reports Server (NTRS)

    Sevener, Kathy; Chen, Zhe; Daly, Sam; Tracy, Jared; Kiser, Doug

    2016-01-01

    With CMC components poised to complete flight certification in turbine engines on commercial aircraft within the near future, there are many efforts within the aerospace community to model the mechanical and environmental degradation of CMCs. Direct observations of damage evolution are needed to support these modeling efforts and provide quantitative measures of damage parameters used in the various models. This study was performed to characterize the damage evolution during tensile loading of a melt infiltrated (MI) silicon carbide reinforced silicon carbide (SiC/SiC) composite. A SiC/SiC tensile coupon was loaded to a maximum global stress of 30 ksi in a tensile fixture within an SEM while observations were made at 5 ksi increments. Both traditional image analysis and DIC (digital image correlation) were used to quantify damage evolution. With the DIC analysis, microscale damage was observed at the fiber-matrix interfaces at stresses as low as 5 ksi. First matrix cracking took place between 20 and 25 ksi, accompanied by an observable relaxation in strain near matrix cracks. Matrix crack opening measurements at the maximum load ranged from 200 nm to 1.5 m. Crack opening along the fiber-matrix interface was also characterized as a function of load and angular position relative to the loading axis. This characterization was funded by NASA GRC and was performed to support NASA GRC modeling of SiC/SiC environmental degradation

  7. Brittle dynamic damage due to earthquake rupture

    NASA Astrophysics Data System (ADS)

    Bhat, Harsha; Thomas, Marion

    2016-04-01

    The micromechanical damage mechanics formulated by Ashby and Sammis, 1990, and generalized by Deshpande and Evans 2008 has been extended to allow for a more generalized stress state and to incorporate an experimentally motivated new crack growth (damage evolution) law that is valid over a wide range of loading rates. This law is sensitive to both the crack tip stress field and its time derivative. Incorporating this feature produces additional strain-rate sensitivity in the constitutive response. The model is also experimentally verified by predicting the failure strength of Dionysus-Pentelicon marble over wide range of strain rates. We then implement this constitutive response to understand the role of dynamic brittle off-fault damage on earthquake ruptures. We show that off-fault damage plays an important role in asymmetry of rupture propagation and is a source of high-frequency ground motion in the near source region.

  8. Modeling electrical power absorption and thermally-induced biological tissue damage.

    PubMed

    Zohdi, T I

    2014-01-01

    This work develops a model for thermally induced damage from high current flow through biological tissue. Using the first law of thermodynamics, the balance of energy produced by the current and the energy absorbed by the tissue are investigated. The tissue damage is correlated with an evolution law that is activated upon exceeding a temperature threshold. As an example, the Fung material model is used. For certain parameter choices, the Fung material law has the ability to absorb relatively significant amounts of energy, due to its inherent exponential response character, thus, to some extent, mitigating possible tissue damage. Numerical examples are provided to illustrate the model's behavior.

  9. Synergistic Effects of Temperature, Oxidation and Multicracking Modes on Damage Evolution and Life Prediction of 2D Woven Ceramic-Matrix Composites under Tension-Tension Fatigue Loading

    NASA Astrophysics Data System (ADS)

    Longbiao, Li

    2016-11-01

    In this paper, the synergistic effects of temperature, oxidation and multicracking modes on damage evolution and life prediction in 2D woven ceramic-matrix composites (CMCs) have been investigated. The damage parameter of fatigue hysteresis dissipated energy and the interface shear stress were used to monitor the damage evolution inside of CMCs. Under cyclic fatigue loading, the fibers broken fraction was determined by combining the interface/fiber oxidation model, interface wear model and fibers statistical failure model at elevated temperature, based on the assumption that the fiber strength is subjected to two-parameter Weibull distribution and the load carried by broken and intact fibers satisfy the Global Load Sharing (GLS) criterion. When the broken fibers fraction approaches to the critical value, the composite fatigue fractures. The evolution of fatigue hysteresis dissipated energy, the interface shear stress and broken fibers fraction versus cycle number, and the fatigue life S-N curves of SiC/SiC at 1000, 1200 and 1300 °C in air and steam condition have been predicted. The synergistic effects of temperature, oxidation, fatigue peak stress, and multicracking modes on the evolution of interface shear stress and fatigue hysteresis dissipated energy versus cycle numbers curves have been analyzed.

  10. Damage-induced nonassociated inelastic flow in rock salt

    SciTech Connect

    Chan, K.S.; Bodner, S.R.; Brodsky, N.S.; Fossum, A.F.

    1993-06-01

    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.

  11. A damage analysis for brittle materials using stochastic micro-structural information

    NASA Astrophysics Data System (ADS)

    Lin, Shih-Po; Chen, Jiun-Shyan; Liang, Shixue

    2016-03-01

    In this work, a micro-crack informed stochastic damage analysis is performed to consider the failures of material with stochastic microstructure. The derivation of the damage evolution law is based on the Helmholtz free energy equivalence between cracked microstructure and homogenized continuum. The damage model is constructed under the stochastic representative volume element (SRVE) framework. The characteristics of SRVE used in the construction of the stochastic damage model have been investigated based on the principle of the minimum potential energy. The mesh dependency issue has been addressed by introducing a scaling law into the damage evolution equation. The proposed methods are then validated through the comparison between numerical simulations and experimental observations of a high strength concrete. It is observed that the standard deviation of porosity in the microstructures has stronger effect on the damage states and the peak stresses than its effect on the Young's and shear moduli in the macro-scale responses.

  12. Yearly evolution of organ damage markers in diabetes or metabolic syndrome: data from the LOD-DIABETES study

    PubMed Central

    2011-01-01

    Background Cardiovascular disease morbidity-mortality is greater in people with type 2 diabetes mellitus or metabolic syndrome. The purpose of this study was to evaluate the yearly evolution of organ damage markers in diabetes or metabolic syndrome, and to analyze the associated factors. Methods An observational prospective study was carried out in the primary care setting, involving 112 patients: 68 diabetics and 44 subjects with metabolic syndrome, subjected to 12 months of follow-up. Measurements: traditional cardiovascular risk factors (blood pressure, blood glucose, lipids, smoking, body mass index (BMI) and) and non-traditional risk factors (waist circumference, hsC Reactive Protein and fibrinogen); subclinical vascular (carotid intima-media thickness, pulse wave velocity and ankle/brachial index), cardiac (Cornell voltage-duration product), renal organ damage (creatinine, glomerular filtration and albumin/creatinine index), and antihypertensive and lipid-lowering drugs. Results At baseline, the diabetics presented a mean age of 59.9 years, versus 55.2 years in the subjects with metabolic syndrome (p = 0.03). Diastolic blood pressure, total cholesterol and HDL-cholesterol were lower among the patients with diabetes, while blood glucose and HbA1c, as well as antihypertensive and lipid-lowering drug use, were greater. At evaluation after one year, the diabetics showed a decrease in BMI (-0.39), diastolic blood pressure (-3.59), and an increase in fibrinogen (30.23 mg/dL), ankle/brachial index (0.07) and the number of patients with ankle/brachial index pathologic decreased in 6. In turn, the patients with metabolic syndrome showed an increase in HDL-cholesterol (1-91 mg/dL), fibrinogen (25.54 mg/dL), Cornell voltage-duration product (184.22 mm/ms), ankle/brachial index (0.05) and the use of antihypertensive and lipid-lowering drugs, and a reduction in serum glucose (3.74 mg/dL), HOMA, systolic (-6.76 mmHg), diastolic blood pressure (-3.29 mmHg), and pulse wave

  13. Determination of Paris' law constants and crack length evolution via Extended and Unscented Kalman filter: An application to aircraft fuselage panels

    NASA Astrophysics Data System (ADS)

    Wang, Yiwei; Binaud, Nicolas; Gogu, Christian; Bes, Christian; Fu, Jian

    2016-12-01

    Prediction of fatigue crack length in aircraft fuselage panels is one of the key issues for aircraft structural safety since it helps prevent catastrophic failures. Accurate estimation of crack length propagation is also meaningful for helping develop aircraft maintenance strategies. Paris' law is often used to capture the dynamics of fatigue crack propagation in metallic material. However, uncertainties are often present in the crack growth model, measured crack size and pressure differential in each flight and need to be accounted for accurate prediction. The aim of this paper is to estimate the two unknown Paris' law constants m and C as well as the crack length evolution by taking into account these uncertainties. Due to the nonlinear nature of the Paris' law, we propose here an on-line estimation algorithm based on two widespread nonlinear filtering techniques, Extended Kalman filter (EKF) and Unscented Kalman filter (UKF). The numerical experiments indicate that both EKF and UKF estimated the crack length well and accurately identified the unknown parameters. Although UKF is theoretical superior to EKF, in this Paris' law application EKF is comparable in accuracy to UKF and requires less computational expense.

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

    SciTech Connect

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

    2002-12-01

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

  15. The effects of shockwave profile shape and shock obliquity on spallation : studies of kinetics and stress state effects on damage evolution

    SciTech Connect

    Gray, George T., III; Hull, Larry M; Faulkner, J R; Briggs, M E; Cerreta, E K; Addessio, F L; Bourne, N K

    2009-06-22

    Shock-loading of a material in contact with a high explosive (HE) experiences a 'Taylor wave' (triangular wave) loading profile in contrast to the square-wave loading profile imparted via the impact of a flyer plate. Detailed metallographic and mlcrotextural analysis of the damage evolution in spalled Cu samples as a function of square/triangle and sweeping detonation-wave loading is presented.

  16. Influence of sweeping detonation-wave loading on damage evolution during spallation loading of tantalum in both a planar and curved geometry

    SciTech Connect

    Gray, George Thompson III; Hull, Lawrence Mark; Livescu, Veronica; Faulkner, James; Briggs, Matthew E.; Meyer, Ross Keith; Andrews, Heather Lynn; Hare, Steven John; Jakulewicz, Micah Shawn; Shinas, Michael A.

    2015-03-30

    Widespread research over the past five decades has provided a wealth of experimental data and insight concerning the shock hardening, damage evolution, and the spallation response of materials subjected to square-topped shock-wave loading profiles. However, fewer quantitative studies have been conducted on the effect of direct, in-contact, high explosive (HE)-driven Taylor wave (unsupported shocks) loading on the shock hardening, damage evolution, or spallation response of materials. Systematic studies quantifying the effect of sweeping-detonation wave loading are yet sparser. In this study, the damage evolution and spallation response of Ta is shown to be critically dependent on the peak shock stress, the geometry of the sample (flat or curved plate geometry), and the shock obliquity during sweeping-detonation-wave shock loading. Sweepingwave loading in the flat-plate geometry is observed to: a) yield a lower spall strength than previously documented for 1-D supported-shock-wave loading, b) exhibit increased shock hardening as a function of increasing obliquity, and c) lead to an increased incidence of deformation twin formation with increasing shock obliquity. Sweeping-wave loading of a 10 cm radius curved Ta plate is observed to: a) lead to an increase in the shear stress as a function of increasing obliquity, b) display a more developed level of damage evolution, extensive voids and coalescence, and lower spall strength with obliquity in the curved plate than seen in the flat-plate sweeping-detonation wave loading for an equivalent HE loading, and c) no increased propensity for deformation twin formation with increasing obliquity as seen in the flat-plate geometry. The overall observations comparing and contrasting the flat versus curved sweeping-wave spall experiments with 1D loaded spallation behavior suggests a coupled influence of obliquity and geometry on dynamic shock-induced damage evolution and spall strength. Coupled experimental and modeling research

  17. Farmers, Ranchers, and the Railroad: The Evolution of Fence Law in the Great Plains, 1865-1900

    ERIC Educational Resources Information Center

    Kawashima, Yasuhide

    2010-01-01

    This article is divided into three parts. The first examines specific fencing policies in Kansas, Nebraska, and other Plains states, highlighting the transformation from the "fence-out" to "fence-in" (herd laws) policies. The second part discusses the coming of the railroads to the Great Plains and the farmers and the ranchers…

  18. Development of a viscoelastic continuum damage model for cyclic loading

    NASA Astrophysics Data System (ADS)

    Sullivan, R. W.

    2008-12-01

    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.

  19. Integrability and conservation laws for the nonlinear evolution equations of partially coherent waves in noninstantaneous Kerr media.

    PubMed

    Hansson, T; Lisak, M; Anderson, D

    2012-02-10

    It is shown that the evolution equations describing partially coherent wave propagation in noninstantaneous Kerr media are integrable and have an infinite number of invariants. A recursion relation for generating these invariants is presented, and it is demonstrated how to express them in the coherent density, self-consistent multimode, mutual coherence, and Wigner formalisms.

  20. TP53 copy number expansion is associated with the evolution of increased body size and an enhanced DNA damage response in elephants.

    PubMed

    Sulak, Michael; Fong, Lindsey; Mika, Katelyn; Chigurupati, Sravanthi; Yon, Lisa; Mongan, Nigel P; Emes, Richard D; Lynch, Vincent J

    2016-09-19

    A major constraint on the evolution of large body sizes in animals is an increased risk of developing cancer. There is no correlation, however, between body size and cancer risk. This lack of correlation is often referred to as 'Peto's Paradox'. Here, we show that the elephant genome encodes 20 copies of the tumor suppressor gene TP53 and that the increase in TP53 copy number occurred coincident with the evolution of large body sizes, the evolution of extreme sensitivity to genotoxic stress, and a hyperactive TP53 signaling pathway in the elephant (Proboscidean) lineage. Furthermore, we show that several of the TP53 retrogenes (TP53RTGs) are transcribed and likely translated. While TP53RTGs do not appear to directly function as transcription factors, they do contribute to the enhanced sensitivity of elephant cells to DNA damage and the induction of apoptosis by regulating activity of the TP53 signaling pathway. These results suggest that an increase in the copy number of TP53 may have played a direct role in the evolution of very large body sizes and the resolution of Peto's paradox in Proboscideans.

  1. TP53 copy number expansion is associated with the evolution of increased body size and an enhanced DNA damage response in elephants

    PubMed Central

    Sulak, Michael; Fong, Lindsey; Mika, Katelyn; Chigurupati, Sravanthi; Yon, Lisa; Mongan, Nigel P; Emes, Richard D; Lynch, Vincent J

    2016-01-01

    A major constraint on the evolution of large body sizes in animals is an increased risk of developing cancer. There is no correlation, however, between body size and cancer risk. This lack of correlation is often referred to as 'Peto's Paradox'. Here, we show that the elephant genome encodes 20 copies of the tumor suppressor gene TP53 and that the increase in TP53 copy number occurred coincident with the evolution of large body sizes, the evolution of extreme sensitivity to genotoxic stress, and a hyperactive TP53 signaling pathway in the elephant (Proboscidean) lineage. Furthermore, we show that several of the TP53 retrogenes (TP53RTGs) are transcribed and likely translated. While TP53RTGs do not appear to directly function as transcription factors, they do contribute to the enhanced sensitivity of elephant cells to DNA damage and the induction of apoptosis by regulating activity of the TP53 signaling pathway. These results suggest that an increase in the copy number of TP53 may have played a direct role in the evolution of very large body sizes and the resolution of Peto's paradox in Proboscideans. DOI: http://dx.doi.org/10.7554/eLife.11994.001 PMID:27642012

  2. Postbuckling Investigations of Piezoelectric Microdevices Considering Damage Effects

    PubMed Central

    Sun, Zhigang; Wang, Xianqiao

    2014-01-01

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

  3. Postbuckling investigations of piezoelectric microdevices considering damage effects.

    PubMed

    Sun, Zhigang; Wang, Xianqiao

    2014-03-11

    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.

  4. The Continued Evolution of U.S. Law of Armed Conflict Implementation: Implications for the U.S. Military

    DTIC Science & Technology

    2015-01-01

    Big Data, and the Changing Face of Conflict,” Georgetown Journal of International Affairs, 2014a, pp. 108–118. 42 The Continued Evolution of U.S...NLWs have already been developed and are in use by U.S. forces, such as Tasers and flash bang grenades.21 Current U.S. Department of Defense policy...Navy’s Tiny 5-Pound Missile Packs a Big Punch,” Wired, February 28, 2014; Jon Rosamond, “USN Spike Miniature PGM Success- fully Engages FIAC Targets

  5. Damage characterization for particles filled semi-crystalline polymer

    NASA Astrophysics Data System (ADS)

    Lauro, Franck; Balieu, Romain; Bennani, Bruno; Haugou, Gregory; Bourel, Benjamin; Chaari, Fahmi; Matsumoto, Tsukatada; Mottola, Ernesto

    2015-09-01

    Damage evolution and characterization in semi-crystalline polymer filled with particles under various loadings is still a challenge. A specific damage characterization method using Digital Image Correlation is proposed for a wide range of strain rates considering tensile tests with hydraulic jacks as well as Hopkinson's bars. This damage measurement is obtained by using and adapting the SEE method [1] which was developed to characterize the behaviour laws at constant strain rates of polymeric materials in dynamic. To validate the characterization process, various damage measurement techniques are used under quasi-static conditions before to apply the procedure in dynamic. So, the well-known damage characterization by loss of stiffness technique under quasi-static loading is applied to a polypropylene. In addition, an in-situ tensile test, carried out in a microtomograph, is used to observe the cavitation phenomenon in real time. A good correlation is obtained between all these techniques and consequently the proposed technique is supposed suitable for measuring the ductile damage observed in semi-crystalline polymers under dynamic loading. By applying it to the semi-crystalline polymer at moderate and high speed loadings, the damage evolution is measured and it is observed that the damage evolution is not strain rate dependent but the failure strain on the contrary is strain rate dependent.

  6. Continuum damage modeling for ductile metals under high strain rate deformation

    NASA Astrophysics Data System (ADS)

    Husson, C.; Ahzi, S.; Daridon, L.; Courtine, T.

    2003-09-01

    The accuracy of the computational investigation on the response of ductile materials under dynamic condition depends on the capability of the constitutive model in accounting for strain rate, temperature and microstructural effects. In this work, we propose a damage evolution law, valid for a wide range of strain rates, based on the theory of continuum damage mechanics (CDM). This model implicitly accounts for the three stages of damage: the nucleation, the growth and the coalescence. This non-linear isotropic CDM model for ductile damage is developed by assuming the existence of a new ductile damage dissipation potential. The proposed damage law is coupled with an evolution law for the flow stress. Like in the mechanical threshold stress (M.T.S.) model, the flow stress is decomposed as the sum of an athermal component and a temperature and strain rate dependent component. Results from our motel are in agreement with the existing experimental results for stress-strain behavior and damage evolution in oxygen-free high-conducting (OFHC) copper under both quasi-static and dynamic loading conditions.

  7. Statistical Analysis of Japanese Structural Damage Data

    DTIC Science & Technology

    1977-01-01

    Calculated Peak Overpressure Data ......... .. 36 Figure 4. Frequency Functions for Assumed Damage Laws ............ .. 38 Figure 5. Conversions to Value of...Buildings .... .......... .. 92 Figure 20. Effect of Damage Law on Confidence Regions ............ .. 97 * Figure 21. Comparison of Confidence Limits on...Value of ad (Cumulative Log Normal Damage Law ) ...... ............ .. 99 * Figure 22. Comparison of Confidence Limits on Value of ad (Cumulative Log

  8. 77 FR 31827 - Pipeline Safety: Pipeline Damage Prevention Programs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-30

    ... Safety: Pipeline Damage Prevention Programs AGENCY: Pipeline and Hazardous Materials Safety... excavation damage prevention law enforcement programs; establish an administrative process for making... excavation damage prevention law enforcement programs; and establish the adjudication process...

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

    SciTech Connect

    Nagy, Peter

    2013-09-30

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

  10. Biochemical, cellular, and molecular mechanisms in the evolution of secondary damage after severe traumatic brain injury in infants and children: Lessons learned from the bedside.

    PubMed

    Kochanek, Patrick M.; Clark, Robert S.B.; Ruppel, Randall A.; Adelson, P. David; Bell, Michael J.; Whalen, Michael J.; Robertson, Courtney L.; Satchell, Margaret A.; Seidberg, Neal A.; Marion, Donald W.; Jenkins, Larry W.

    2000-07-01

    OBJECTIVE: To present a state-of-the-art review of mechanisms of secondary injury in the evolution of damage after severe traumatic brain injury in infants and children. DATA SOURCES: We reviewed 152 peer-reviewed publications, 15 abstracts and proceedings, and other material relevant to the study of biochemical, cellular, and molecular mechanisms of damage in traumatic brain injury. Clinical studies of severe traumatic brain injury in infants and children were the focus, but reports in experimental models in immature animals were also considered. Results from both clinical studies in adults and models of traumatic brain injury in adult animals were presented for comparison. DATA SYNTHESIS: Categories of mechanisms defined were those associated with ischemia, excitotoxicity, energy failure, and resultant cell death cascades; secondary cerebral swelling; axonal injury; and inflammation and regeneration. CONCLUSIONS: A constellation of mediators of secondary damage, endogenous neuroprotection, repair, and regeneration are set into motion in the brain after severe traumatic injury. The quantitative contribution of each mediator to outcome, the interplay between these mediators, and the integration of these mechanistic findings with novel imaging methods, bedside physiology, outcome assessment, and therapeutic intervention remain an important target for future research.

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

    PubMed

    Rath, Johannes; Ischi, Monique; Perkins, Dana

    2014-09-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

  13. Dynamic Response and Damage Evolution in Composite Materials Subjected to Underwater Explosive Loading: An Experimental and Computational Study

    DTIC Science & Technology

    2010-01-01

    testing , utilizing a water filled conical shock tube and computational sim- ulations, utilizing the commercially available LS - DYNA finite element code... composites have utilized LS - DYNA and the Mat_162 (Mat_Composite_OPTION) material model which simulates fiber breakage, matrix cracking and delamination damage...ARTICLE IN PRESS5. Finite element modeling Finite element modeling of the testing has been performed uti- lizing the LS - DYNA code available from the

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

    SciTech Connect

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

    2010-10-26

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

  15. Effects of processing history on the evolution of surface damage layer and dislocation substructure in large grain niobium cavities

    NASA Astrophysics Data System (ADS)

    Kang, D.; Bieler, T. R.; Compton, C.

    2015-12-01

    Large grain niobium (Nb) is being investigated for fabricating superconducting radiofrequency cavities as an alternative to the traditional approach using fine grain polycrystalline Nb sheets. Past studies have identified a surface damage layer on fine grain cavities due to deep drawing and demonstrated the necessity for chemical etching on the surface. However, the origin of and depth of the damage layer are not well understood, and similar exploration on large grain cavities is lacking. In this work, electron backscatter diffraction (EBSD) was used to examine the cross sections at the equator and iris of a half cell deep drawn from a large grain Nb ingot slice. The results indicate that the damage (identified by a high density of geometrically necessary dislocations) depends on crystal orientations, is different at the equator and iris, and is present through the full thickness of a half cell in some places. After electron backscatter diffraction, the specimens were heat treated at 800 °C or 1000 °C for two hours, and the same areas were reexamined. A more dramatic decrease in dislocation content was observed at the iris than the equator, where some regions exhibited no change. The specimens were then etched and examined again, to determine if the subsurface region behaved differently than the surface. Little change in the dislocation substructure was observed, suggesting that the large grain microstructure is retained with a normal furnace anneal.

  16. Continuum damage model for ferroelectric materials and its application to multilayer actuators

    NASA Astrophysics Data System (ADS)

    Gellmann, Roman; Ricoeur, Andreas

    2016-05-01

    In this paper a micromechanical continuum damage model for ferroelectric materials is presented. As a constitutive law it is implemented into a finite element (FE) code. The model is based on micromechanical considerations of domain switching and its interaction with microcrack growth and coalescence. A FE analysis of a multilayer actuator is performed, showing the initiation of damage zones at the electrode tips during the poling process. Further, the influence of mechanical pre-stressing on damage evolution and actuating properties is investigated. The results provided in this work give useful information on the damage of advanced piezoelectric devices and their optimization.

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

    PubMed

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

    2015-06-01

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

  18. Damage 90: A post processor for crack initiation

    NASA Astrophysics Data System (ADS)

    Lemaitre, Jean; Doghri, Issam

    1994-05-01

    A post processor is fully described which allows the calculation of the crack initiation conditions from the history of strain components taken as the output of a finite element calculation. It is based upon damage mechanics using coupled strain damage constitutive equations for linear isotropic elasticity, perfect plasticity and a unified kinetic law of damage evolution. The localization of damage allows this coupling to be considered only for the damaging point for which the input strain history is taken from a classical structure calculation in elasticity or elastoplasticity. The listing of the code, a `friendly' code, with less than 600 FORTRAN instructions is given and some examples show its ability to model ductile failure in one or multi dimensions, brittle failure, low and high cycle fatigue with the non-linear accumulation, and multi-axial fatigue.

  19. Modeling Fatigue Damage in Long-Fiber Thermoplastics

    SciTech Connect

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

    2009-10-30

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

  20. Damage evolution of ion irradiated defected-fluorite La2Zr2O7 epitaxial thin films

    DOE PAGES

    Kaspar, Tiffany C.; Gigax, Jonathan G.; Shao, Lin; ...

    2017-01-13

    Pyrochlore-structure oxides, A2B2O7, may exhibit remarkable radiation tolerance due to the ease with which they can accommodate disorder by transitioning to a defected fluorite structure. In this paper, the mechanism of defect formation was explored by evaluating the radiation damage behavior of high quality epitaxial La2Zr2O7 thin films with the defected fluorite structure, irradiated with 1 MeV Zr+ at doses up to 10 displacements per atom (dpa). The level of film damage was evaluated as a function of dose by Rutherford backscattering spectrometry in the channeling geometry (RBS/c) and scanning transmission electron microscopy (STEM). At lower doses, the surface ofmore » the La2Zr2O7 film amorphized, and the amorphous fraction as a function of dose fit well to a stimulated amorphization model. As the dose increased, the surface amorphization slowed, and amorphization appeared at the interface. Even at a dose of 10 dpa, the core of the film remained crystalline, despite the prediction of amorphization from the model. To inform future ab initio simulations of La2Zr2O7, the bandgap of a thick La2Zr2O7 film was measured to be indirect at 4.96 eV, with a direct transition at 5.60 eV.« less

  1. Damage evolution of ion irradiated defected-fluorite La 2 Zr 2 O 7 epitaxial thin films

    DOE PAGES

    Kaspar, Tiffany C.; Gigax, Jonathan G.; Shao, Lin; ...

    2017-05-01

    Pyrochlore-structure oxides, A2B2O7, may exhibit remarkable radiation tolerance due to the ease with which they can accommodate disorder by transitioning to a defected fluorite structure. In this paper, the mechanism of defect formation was explored by evaluating the radiation damage behavior of high quality epitaxial La2Zr2O7 thin films with the defected fluorite structure, irradiated with 1 MeV Zr+ at doses up to 10 displacements per atom (dpa). The level of film damage was evaluated as a function of dose by Rutherford backscattering spectrometry in the channeling geometry (RBS/c) and scanning transmission electron microscopy (STEM). At lower doses, the surface ofmore » the La2Zr2O7 film amorphized, and the amorphous fraction as a function of dose fit well to a stimulated amorphization model. As the dose increased, the surface amorphization slowed, and amorphization appeared at the interface. Even at a dose of 10 dpa, the core of the film remained crystalline, despite the prediction of amorphization from the model. To inform future ab initio simulations of La2Zr2O7, the bandgap of a thick La2Zr2O7 film was measured to be indirect at 4.96 eV, with a direct transition at 5.60 eV.« less

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

    SciTech Connect

    Deng, S.; Weitsman, Y.J.

    2000-03-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-02-01

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

  4. Frictional evolution, acoustic emissions activity, and off-fault damage in simulated faults sheared at seismic slip rates

    NASA Astrophysics Data System (ADS)

    Passelègue, François. X.; Spagnuolo, Elena; Violay, Marie; Nielsen, Stefan; Di Toro, Giulio; Schubnel, Alexandre

    2016-10-01

    We present a series of high-velocity friction tests conducted on Westerly granite, using the Slow to HIgh Velocity Apparatus (SHIVA) installed at Istituto Nazionale di Geofisica e Vulcanologia Roma with acoustic emissions (AEs) monitored at high frequency (4 MHz). Both atmospheric humidity and pore fluid (water) pressure conditions were tested, under effective normal stress σneff in the range 5-20 MPa and at target sliding velocities Vs in the range 0.003-3 m/s. Under atmospheric humidity two consecutive friction drops were observed. The first one is related to flash weakening, and the second one to the formation and growth of a continuous layer of melt in the slip zone. In the presence of fluid, a single drop in friction was observed. Average values of fracture energy are independent of effective normal stress and sliding velocity. However, measurements of elastic wave velocities on the sheared samples suggested that larger damage was induced for 0.1 < Vs<0.3 m/s. This observation is supported by AEs recorded during the test, most of which were detected after the initiation of the second friction drop, once the fault surface temperature was high. Some AEs were detected up to a few seconds after the end of the experiments, indicating thermal rather than mechanical cracking. In addition, the presence of pore water delayed the onset of AEs by cooling effects and by reducing of the heat produced, supporting the link between AEs and the production and diffusion of heat during sliding. Using a thermoelastic crack model developed by Fredrich and Wong (1986), we confirm that damage may be induced by heat diffusion. Indeed, our theoretical results predict accurately the amount of shortening and shortening rate, supporting the idea that gouge production and gouge comminution are in fact largely controlled by thermal cracking. Finally, we discuss the contribution of thermal cracking in the seismic energy balance. In fact, while a dichotomy exists in the literature regarding

  5. A Dynamic Damage Mechanics Source Model for Explosions in Crystalline Rock

    NASA Astrophysics Data System (ADS)

    Mihaly, J. M.; Bhat, H. S.; Sammis, C. G.; Rosakis, A.

    2011-12-01

    The micromechanical damage mechanics formulated by Ashby and Sammis [PAGEOPH, 1990] and generalized by Deshpande and Evans [J. Mech. Phys. Solids, 2008] has been extended to allow for a more generalized stress state and to incorporate an experimentally motivated crack growth (damage evolution) law that is valid over a wide range of loading rates. This law is sensitive to both the crack tip stress field and its time derivative, and thus produces strain-rate sensitivity in the constitutive response. The model is experimentally verified by predicting the failure strength of Dionysus-Pentelicon marble over strain rates ranging from to . This rate-dependent damage mechanics has been implemented in the ABAQUS dynamic finite element code and used to explore the effects of burn rate (loading rate) and lithostatic stress on the spatial extent of fracture damage and S waves generated by explosions in crystalline rock. Slower rise times and longer pressure pulses produce more damage and stronger S waves.

  6. International law and law enforcement firearms.

    PubMed

    Jussila, Jorma; Normia, Pertti

    2004-01-01

    Several international agreements set constraints on the legitimate use of firearms as representing lethal force. Their meaning in terms of weapons technology must take into account their operational frame of reference, and legitimate warfare can be regarded as a law enforcement operation with similar principles on the use of force. Changes in weapons technology, such as new types of ammunition, transforming firearms into weapons with less-lethal and even humanitarian options, require new interpretations of the legislation. A division into lethal and non-lethal weapons is an oversimplification and the separation of international humanitarian law into military and law enforcement provisions can be questioned from the technical aspect. The type of technology acceptable for law enforcement use of firearms should be defined. An assessment for weapon injury should not be based on lethality, but rather on the potential for tissue damage and its reversibility.

  7. Coupled Crystal Plasticity-Phase Field Fracture Simulation Study on Damage Evolution Around a Void: Pore Shape Versus Crystallographic Orientation

    NASA Astrophysics Data System (ADS)

    Diehl, Martin; Wicke, Marcel; Shanthraj, Pratheek; Roters, Franz; Brueckner-Foit, Angelika; Raabe, Dierk

    2017-03-01

    Various mechanisms such as anisotropic plastic flow, damage nucleation, and crack propagation govern the overall mechanical response of structural materials. Understanding how these mechanisms interact, i.e. if they amplify mutually or compete with each other, is an essential prerequisite for the design of improved alloys. This study shows—by using the free and open source software DAMASK (the Düsseldorf Advanced Material Simulation Kit)—how the coupling of crystal plasticity and phase field fracture methods can increase the understanding of the complex interplay between crystallographic orientation and the geometry of a void. To this end, crack initiation and propagation around an experimentally obtained pore with complex shape is investigated and compared to the situation of a simplified spherical void. Three different crystallographic orientations of the aluminum matrix hosting the defects are considered. It is shown that crack initiation and propagation depend in a non-trivial way on crystallographic orientation and its associated plastic behavior as well as on the shape of the pore.

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

    PubMed

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

    2014-05-21

    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.

  9. Damage evolution of bi-body model composed of weakly cemented soft rock and coal considering different interface effect.

    PubMed

    Zhao, Zenghui; Lv, Xianzhou; Wang, Weiming; Tan, Yunliang

    2016-01-01

    Considering the structure effect of tunnel stability in western mining of China, three typical kinds of numerical model were respectively built as follows based on the strain softening constitutive model and linear elastic-perfectly plastic model for soft rock and interface: R-M, R-C(s)-M and R-C(w)-M. Calculation results revealed that the stress-strain relation and failure characteristics of the three models vary between each other. The combination model without interface or with a strong interface presented continuous failure, while weak interface exhibited 'cut off' effect. Thus, conceptual models of bi-material model and bi-body model were established. Then numerical experiments of tri-axial compression were carried out for the two models. The relationships between stress evolution, failure zone and deformation rate fluctuations as well as the displacement of interface were detailed analyzed. Results show that two breakaway points of deformation rate actually demonstrate the starting and penetration of the main rupture, respectively. It is distinguishable due to the large fluctuation. The bi-material model shows general continuous failure while bi-body model shows 'V' type shear zone in weak body and failure in strong body near the interface due to the interface effect. With the increasing of confining pressure, the 'cut off' effect of weak interface is not obvious. These conclusions lay the theoretical foundation for further development of constitutive model for soft rock-coal combination body.

  10. 32 CFR 842.66 - Applicable law.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... determine the applicable law for assessment of liability. (a) A claim is settled under the law and standards... in the apportionment of liability. The amount of damage sustained by both parties is...

  11. 32 CFR 842.66 - Applicable law.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... determine the applicable law for assessment of liability. (a) A claim is settled under the law and standards... in the apportionment of liability. The amount of damage sustained by both parties is...

  12. 32 CFR 842.66 - Applicable law.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... determine the applicable law for assessment of liability. (a) A claim is settled under the law and standards... in the apportionment of liability. The amount of damage sustained by both parties is...

  13. 32 CFR 842.66 - Applicable law.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... determine the applicable law for assessment of liability. (a) A claim is settled under the law and standards... in the apportionment of liability. The amount of damage sustained by both parties is...

  14. Water, law, science

    SciTech Connect

    Narasimhan, T.N.

    2007-10-17

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

  15. Evolution of target organ damage and haemodynamic parameters over 4 years in patients with increased insulin resistance: the LOD-DIABETES prospective observational study

    PubMed Central

    Gómez-Marcos, Manuel Ángel; Recio-Rodríguez, José Ignacio; Patino-Alonso, María Carmen; Agudo-Conde, Cristina; Rodríguez-Sanchez, Emiliano; Maderuelo-Fernandez, Jose Angel; Gómez-Sánchez, Leticia; Gomez-Sanchez, Marta; García-Ortiz, Luís

    2016-01-01

    Objectives We prospectively examined the impact of type 2 diabetes compared with metabolic syndrome (MetS) on the development of vascular disease over 4 years as determined by anatomic and functional markers of vascular disease. By comparing the vascular outcomes of the 2 disorders, we seek to determine the independent effect of elevated glucose levels on vascular disease. Setting 2 primary care centres in Salamanca, Spain. Participants We performed a prospective observational study involving 112 patients (68 with type 2 diabetes and 44 with MetS) who were followed for 4 years. Primary and secondary outcome measures Measurements included blood pressure, blood glucose, lipids, smoking, body mass index, waist circumference, Homeostasis Model Assessment Insulin Resistance (HOMA-IR), hs-c-reactive protein and fibrinogen levels. We also evaluated vascular, carotid intima media thickness (IMT), pulse wave velocity (PWV) and ankle/brachial index, heart and renal target organ damage (TOD). The haemodynamic parameters were central (CAIx) and peripheral (PAIx) augmentation indices. Results In year 4, participants with type 2 diabetes had increased IMT thickness. These patients had more plaques and an IMT>0.90 mm. In participants with MetS, we only found an increase in the number of plaques. We found no changes in PWV, CAIx and PAIx. The patients with diabetes had a greater frequency of vascular TOD. There were no differences neither in renal nor cardiac percentage of TOD in the patients with MetS or diabetes mellitus type 2. Conclusions This prospective study showed that the evolution of vascular TOD is different in participants with type 2 diabetes compared with those with MetS. While IMT and PWV increased in type 2 diabetes, these were not modified in MetS. The renal and cardiac TOD evolution, as well as the PAIx and CAIx, did not change in either group. Trial registration number NCT01065155; Results. PMID:27251684

  16. The Law of Higher Education 1980.

    ERIC Educational Resources Information Center

    Kaplin, William A.

    Designed to be used either independently or as a companion to "The Law of Higher Education" (1978), this book serves as a reference to current legal issues, as well as to primary and secondary materials concerning higher education law. Part One, Overview of Postsecondary Education Law, examines the evolution of law relating to postsecondary…

  17. In-situ luminescence monitoring of ion-induced damage evolution in SiO2 and Al2O3

    DOE PAGES

    Crespillo, Miguel L.; Graham, Joseph T.; Zhang, Yanwen; ...

    2015-12-17

    Real-time, in-situ ionoluminescence measurements provide information of evolution of emission bands with ion fluence, and thereby establish a correlation between point defect kinetics and phase stability. Using fast light ions (2 MeV H and 3.5 He MeV) and medium mass-high energy ions (8 MeV O, E=0.5 MeV/amu), scintillation materials of a-SiO2, crystalline quartz, and Al2O3 are comparatively investigated at room temperature with the aim of obtaining a further insight on the structural defects induced by ion irradiation and understand the role of electronic energy loss on the damage processes. For more energetic heavy ions, the electronic energy deposition pattern offersmore » higher rates of excitation deeper into the material and allows to evaluate the competing mechanisms between the radiative and non-radiative de-excitation processes. Irradiations with 8 MeV O ions have been selected corresponding to the electronic stopping regime, where the electronic stopping power is dominant, and above the critical amorphization threshold for quartz. Lastly, the usefulness of IBIL and its specific capabilities as a sensitive tool to investigate the material characterization and evaluation of radiation effects are demonstrated.« less

  18. Limit laws for Zipf's law

    NASA Astrophysics Data System (ADS)

    Eliazar, Iddo

    2011-01-01

    In this communication we establish stochastic limit laws leading from Zipf's law to Pareto's and Heaps' laws. We consider finite ensembles governed by Zipf's law and study their asymptotic statistics as the ensemble size tends to infinity. A Lorenz-curve analysis establishes three types of limit laws for the ensembles' statistical structure: 'communist', 'monarchic', and Paretian. Further considering a dynamic setting in which the ensembles grow stochastically in time, a functional central limit theorem analysis establishes a Gaussian approximation for the ensembles' stochastic growth. The Gaussian approximation provides a generalized and corrected formulation of Heaps' law.

  19. Heat transfer in damaged material

    NASA Astrophysics Data System (ADS)

    Kruis, J.

    2013-10-01

    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.

  20. Darwin's laws.

    PubMed

    Haufe, Chris

    2012-03-01

    There is widespread agreement among contemporary philosophers of biology and philosophically-minded biologists that Darwin's insights about the intrusion of chance processes into biological regularities undermines the possibility of there being biological laws. Darwin made references to "designed laws." He also freely described some laws as having exceptions. This paper provides a philosophical analysis of the notion of scientific laws that was dominant in Darwin's time, and in all probability the one which he inherited. The analysis of laws is then used to show how it could have been natural for Darwin to believe in designed laws that had exceptions, and to highlight the continuity between the metaphysics of pre-Darwinian, Darwinian, and contemporary biological science. One important result is the removal of one motivation for the anti-laws sentiment in philosophy and biology.

  1. Courtside: A Damaging Lesson

    ERIC Educational Resources Information Center

    Zirkel, Perry A.

    2004-01-01

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

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

    SciTech Connect

    Aschwanden, Markus J.; Shimizu, Toshifumi E-mail: shimizu.toshifumi@isas.jaxa.jp

    2013-10-20

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

  3. Exact law of live nature

    NASA Astrophysics Data System (ADS)

    Azbel, Mark Ya.

    2005-07-01

    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.

  4. Violation of Dollo's law: evidence of muscle reversions in primate phylogeny and their implications for the understanding of the ontogeny, evolution, and anatomical variations of modern humans.

    PubMed

    Diogo, Rui; Wood, Bernard

    2012-10-01

    According to Dollo's law, once a complex structure is lost it is unlikely to be reacquired. In this article, we report new data obtained from our myology-based cladistic analyses of primate phylogeny, which provide evidence of anatomical reversions violating Dollo's law: of the 220 character state changes unambiguously optimized in the most parsimonious primate tree, 28 (13%) are evolutionary reversions, and of these 28 reversions six (21%) occurred in the nodes that lead to the origin of modern humans; nine (32%) violate Dollo's law. In some of these nine cases, the structures that were lost in adults of the last common ancestor and are absent in adults of most subgroups of a clade are actually present in early ontogenetic stages of karyotypically normal individuals as well as in later ontogenetic stages of karyotypically abnormal members of those subgroups. Violations of Dollo's law may thus result from the maintenance of ancestral developmental pathways during long periods of trait absence preceding the reacquisition of the trait through paedomorphic events. For instance, the presence of contrahentes and intermetacarpales in adult chimpanzees is likely due to a prolonged/delayed development of the hand musculature, that is, in this case chimpanzees are more neotenic than modern humans.

  5. Battle Brewing Over Arkansas Creationism Law.

    ERIC Educational Resources Information Center

    Baum, Rudy

    1981-01-01

    Reports recent proceedings regarding a new law enacted in early 1981 in Arkansas which requires schools that teach evolution to teach what the law calls "creation-science." Opposition to the law by the American Civil Liberties Union is discussed. (CS)

  6. 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)

    Harrison, W. J.

    1981-01-01

    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.

  7. Limits of imagination: the 150th Anniversary of Mendel's Laws, and why Mendel failed to see the importance of his discovery for Darwin's theory of evolution.

    PubMed

    Singh, Rama S

    2015-09-01

    Mendel is credited for discovering Laws of Heredity, but his work has come under criticism on three grounds: for possible falsification of data to fit his expectations, for getting undue credit for the laws of heredity without having ideas of segregation and independent assortment, and for being interested in the development of hybrids rather than in the laws of heredity. I present a brief review of these criticisms and conclude that Mendel deserved to be called the father of genetics even if he may not, and most likely did not, have clear ideas of segregation and particulate determiners as we know them now. I argue that neither Mendel understood the evolutionary significance of his findings for the problem of genetic variation, nor would Darwin have understood their significance had he read Mendel's paper. I argue that the limits to imagination, in both cases, came from their mental framework being shaped by existing paradigms-blending inheritance in the case of Darwin, hybrid development in the case of Mendel. Like Einstein, Darwin's natural selection was deterministic; like Niels Bohr, Mendel's Laws were probabilistic-based on random segregation of trait-determining "factors". Unlike Einstein who understood quantum mechanics, Darwin would have been at a loss with Mendel's paper with no guide to turn to. Geniuses in their imaginations are like heat-seeking missiles locked-in with their targets of deep interests and they generally see things in one dimension only. Imagination has limits; unaided imagination is like a bird without wings--it goes nowhere.

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

    SciTech Connect

    Elaqra, H.; Godin, N.; Peix, G.; R'Mili, M. . E-mail: Mohamed.Rmili@insa-lyon.fr; Fantozzi, G.

    2007-05-15

    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.

  9. Interacting damage models mapped onto ising and percolation models

    SciTech Connect

    Toussaint, Renaud; Pride, Steven R.

    2004-03-23

    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

  10. Irreversible entropy model for damage diagnosis in resistors

    SciTech Connect

    Cuadras, Angel Crisóstomo, Javier; Ovejas, Victoria J.; Quilez, Marcos

    2015-10-28

    We propose a method to characterize electrical resistor damage based on entropy measurements. Irreversible entropy and the rate at which it is generated are more convenient parameters than resistance for describing damage because they are essentially positive in virtue of the second law of thermodynamics, whereas resistance may increase or decrease depending on the degradation mechanism. Commercial resistors were tested in order to characterize the damage induced by power surges. Resistors were biased with constant and pulsed voltage signals, leading to power dissipation in the range of 4–8 W, which is well above the 0.25 W nominal power to initiate failure. Entropy was inferred from the added power and temperature evolution. A model is proposed to understand the relationship among resistance, entropy, and damage. The power surge dissipates into heat (Joule effect) and damages the resistor. The results show a correlation between entropy generation rate and resistor failure. We conclude that damage can be conveniently assessed from irreversible entropy generation. Our results for resistors can be easily extrapolated to other systems or machines that can be modeled based on their resistance.

  11. 3D Progressive Damage Modeling for Laminated Composite Based on Crack Band Theory and Continuum Damage Mechanics

    NASA Technical Reports Server (NTRS)

    Wang, John T.; Pineda, Evan J.; Ranatunga, Vipul; Smeltzer, Stanley S.

    2015-01-01

    A simple continuum damage mechanics (CDM) based 3D progressive damage analysis (PDA) tool for laminated composites was developed and implemented as a user defined material subroutine to link with a commercially available explicit finite element code. This PDA tool uses linear lamina properties from standard tests, predicts damage initiation with an easy-to-implement Hashin-Rotem failure criteria, and in the damage evolution phase, evaluates the degradation of material properties based on the crack band theory and traction-separation cohesive laws. It follows Matzenmiller et al.'s formulation to incorporate the degrading material properties into the damaged stiffness matrix. Since nonlinear shear and matrix stress-strain relations are not implemented, correction factors are used for slowing the reduction of the damaged shear stiffness terms to reflect the effect of these nonlinearities on the laminate strength predictions. This CDM based PDA tool is implemented as a user defined material (VUMAT) to link with the Abaqus/Explicit code. Strength predictions obtained, using this VUMAT, are correlated with test data for a set of notched specimens under tension and compression loads.

  12. A damage mechanics based general purpose interface/contact element

    NASA Astrophysics Data System (ADS)

    Yan, Chengyong

    Most of the microelectronics packaging structures consist of layered substrates connected with bonding materials, such as solder or epoxy. Predicting the thermomechanical behavior of these multilayered structures is a challenging task in electronic packaging engineering. In a layered structure the most complex part is always the interfaces between the strates. Simulating the thermo-mechanical behavior of such interfaces, is the main theme of this dissertation. The most commonly used solder material, Pb-Sn alloy, has a very low melting temperature 180sp°C, so that the material demonstrates a highly viscous behavior. And, creep usually dominates the failure mechanism. Hence, the theory of viscoplasticity is adapted to describe the constitutive behavior. In a multilayered assembly each layer has a different coefficient of thermal expansion. Under thermal cycling, due to heat dissipated from circuits, interfaces and interconnects experience low cycle fatigue. Presently, the state-of-the art damage mechanics model used for fatigue life predictions is based on Kachanov (1986) continuum damage model. This model uses plastic strain as a damage criterion. Since plastic strain is a stress path dependent value, the criterion does not yield unique damage values for the same state of stress. In this dissertation a new damage evolution equation based on the second law of thermodynamic is proposed. The new criterion is based on the entropy of the system and it yields unique damage values for all stress paths to the final state of stress. In the electronics industry, there is a strong desire to develop fatigue free interconnections. The proposed interface/contact element can also simulate the behavior of the fatigue free Z-direction thin film interconnections as well as traditional layered interconnects. The proposed interface element can simulate behavior of a bonded interface or unbonded sliding interface, also called contact element. The proposed element was verified against

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

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

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

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

    SciTech Connect

    Aschwanden, Markus J.; Zhang, Jie; Liu, Kai E-mail: jzhang7@gmu.edu

    2013-09-20

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

  15. 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)

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

    2013-09-01

    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 κ, spreading exponent β, 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 κvpropL 0.94 ± 0.01 and the three-parameter scaling law Lvpropκ 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 κ than confined flares (without CMEs).

  16. Viscoelastic-damage interface model formulation with friction to simulate the delamination growth in mode II shear

    NASA Astrophysics Data System (ADS)

    Goodarzi, Mohammad Saeed; Hosseini-Toudeshky, Hossein

    2017-02-01

    In this paper a formulation of a viscoelastic-damage interface model with friction in mode-II is presented. The cohesive constitutive law contains elastic and damage regimes. It has been assumed that the shear stress in the elastic regime follows the viscoelastic properties of the matrix material. The three element Voigt model has been used for the formulation of relaxation modulus of the material. Damage evolution proceeds according to the bilinear cohesive constitutive law combined with friction stress consideration. Combination of damage and friction is based on the presumption that the damaged area, related to an integration point, can be dismembered into the un-cracked area with the cohesive damage and cracked area with friction. Samples of a one element model have been presented to see the effect of parameters on the cohesive constitutive law. A comparison between the predicted results with available results of end-notched flexure specimens in the literature is also presented to verify the model. Transverse crack tension specimens are also simulated for different applied displacement velocities.

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

    NASA Technical Reports Server (NTRS)

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

    1998-01-01

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

  18. Evolution of ischemic damage and behavioural deficit over 6 months after MCAo in the rat: Selecting the optimal outcomes and statistical power for multi-centre preclinical trials.

    PubMed

    Rewell, Sarah S J; Churilov, Leonid; Sidon, T Kate; Aleksoska, Elena; Cox, Susan F; Macleod, Malcolm R; Howells, David W

    2017-01-01

    Key disparities between the timing and methods of assessment in animal stroke studies and clinical trial may be part of the reason for the failure to translate promising findings. This study investigates the development of ischemic damage after thread occlusion MCAo in the rat, using histological and behavioural outcomes. Using the adhesive removal test we investigate the longevity of behavioural deficit after ischemic stroke in rats, and examine the practicality of using such measures as the primary outcome for future studies. Ischemic stroke was induced in 132 Spontaneously Hypertensive Rats which were assessed for behavioural and histological deficits at 1, 3, 7, 14, 21, 28 days, 12 and 24 weeks (n>11 per timepoint). The basic behavioural score confirmed induction of stroke, with deficits specific to stroke animals. Within 7 days, these deficits resolved in 50% of animals. The adhesive removal test revealed contralateral neglect for up to 6 months following stroke. Sample size calculations to facilitate the use of this test as the primary experimental outcome resulted in cohort sizes much larger than are the norm for experimental studies. Histological damage progressed from a necrotic infarct to a hypercellular area that cleared to leave a fluid filled cavity. Whilst absolute volume of damage changed over time, when corrected for changes in hemispheric volume, an equivalent area of damage was lost at all timepoints. Using behavioural measures at chronic timepoints presents significant challenges to the basic science community in terms of the large number of animals required and the practicalities associated with this. Multicentre preclinical randomised controlled trials as advocated by the MultiPART consortium may be the only practical way to deal with this issue.

  19. Evolution of ischemic damage and behavioural deficit over 6 months after MCAo in the rat: Selecting the optimal outcomes and statistical power for multi-centre preclinical trials

    PubMed Central

    Churilov, Leonid; Sidon, T. Kate; Aleksoska, Elena; Cox, Susan F.; Macleod, Malcolm R.; Howells, David W.

    2017-01-01

    Key disparities between the timing and methods of assessment in animal stroke studies and clinical trial may be part of the reason for the failure to translate promising findings. This study investigates the development of ischemic damage after thread occlusion MCAo in the rat, using histological and behavioural outcomes. Using the adhesive removal test we investigate the longevity of behavioural deficit after ischemic stroke in rats, and examine the practicality of using such measures as the primary outcome for future studies. Ischemic stroke was induced in 132 Spontaneously Hypertensive Rats which were assessed for behavioural and histological deficits at 1, 3, 7, 14, 21, 28 days, 12 and 24 weeks (n>11 per timepoint). The basic behavioural score confirmed induction of stroke, with deficits specific to stroke animals. Within 7 days, these deficits resolved in 50% of animals. The adhesive removal test revealed contralateral neglect for up to 6 months following stroke. Sample size calculations to facilitate the use of this test as the primary experimental outcome resulted in cohort sizes much larger than are the norm for experimental studies. Histological damage progressed from a necrotic infarct to a hypercellular area that cleared to leave a fluid filled cavity. Whilst absolute volume of damage changed over time, when corrected for changes in hemispheric volume, an equivalent area of damage was lost at all timepoints. Using behavioural measures at chronic timepoints presents significant challenges to the basic science community in terms of the large number of animals required and the practicalities associated with this. Multicentre preclinical randomised controlled trials as advocated by the MultiPART consortium may be the only practical way to deal with this issue. PMID:28182727

  20. Exact law of live nature

    NASA Astrophysics Data System (ADS)

    Azbel‧, Mark Ya.

    2005-08-01

    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.

  1. School Law.

    ERIC Educational Resources Information Center

    Splitt, David A.

    1982-01-01

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

  2. World Law.

    ERIC Educational Resources Information Center

    Marvin, David

    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…

  3. DEVELOPMENT OF CHINESE HEALTH LAW: OVERVIEW AND SUGGESTIONS.

    PubMed

    Liu, Kai; Tang, Daolu

    2014-07-01

    Health law is a rapidly developing law specialty in China. This article examines the current overall framework and evolution of Chinese health law, as a background to an analysis of the advantages and disadvantages of this legal regime. Research suggests that: 1) The independent status of Chinese health law as jurisprudence and a specialty ought to be assured altogether; 2) The convergence between health law and other laws should be strengthened; 3) The current Chinese health law framework ought to be completed. This suggests the necessity to find ways to improve the independence of health law in China by eliminating the convergence and completing the legal framework.

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

    SciTech Connect

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

    2013-04-08

    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.

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

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  6. Forecasting Frost Damage: Follow the Water

    NASA Astrophysics Data System (ADS)

    Rempel, A. W.

    2015-12-01

    Frost damage takes place when the pressure exerted against pore walls exceeds the cohesive strength of water-infiltrated rock and causes cracks to extend. Elegant theoretical treatments supported by meticulous field and laboratory observations have combined to unravel the basic mechanical and thermodynamic controls in idealized systems. Frost damage is most vigorous when conditions are cold enough that the net pressure exerted against the pore walls can cause crack extension, yet warm enough to enable the flow that supplies further ice growth in the newly opened space. This insight is applied here to develop practical geomorphic process laws for the effects of frost damage at the larger scales that are relevant for describing the evolution of landscapes. To this end, a direct connection is made between the intensity of frost damage and the porosity increase that results from gradients in water flux under conditions that are cold enough for ice-rock interactions to propagate cracks. This implies that the annual temperature variation at the ground surface can be combined with considerations of heat and mass transport to derive rigorous forecasts of the potential for frost damage that are tied to the increases in water mass that accompany solidification in porous rock. As an example, the image shows the depth-integrated porosity change λ promoted by crack growth at temperatures colder than -ΔTc over an annual cycle for different choices of mean annual temperature MAT and surface amplitude A (assuming a thermal diffusivity of 1 mm2/s and a power-law relationship between permeability and undercooling with exponent α=4, such that a base value of 10-14m2 is reached at a reference undercooling of 0.1 ºC). The abrupt onset in cracking once MAT decreases below a threshold is produced by the requirement that undercooling surpass ΔTc in order to generate sufficient pressures to propagate cracks. The eventual reduction and gradual tail in λ at colder MAT is produced by

  7. Stigma law.

    PubMed

    1998-10-30

    Massachusetts enacted a law, called House No. 2099, that relieves real estate brokers from liability for not disclosing the history of a property to a potential buyer. The statute says that certain information does not need to be disclosed in a real estate transaction. Such information includes whether any previous occupants had HIV/AIDS or any other disease that is unlikely to be transmitted casually.

  8. Stochastics of diffusion induced damage in intercalation materials

    NASA Astrophysics Data System (ADS)

    Barai, Pallab; Mukherjee, Partha P.

    2016-10-01

    Fundamental understanding of the underlying diffusion-mechanics interplay in the intercalation electrode materials is critical toward improved life and performance of lithium-ion batteries for electric vehicles. Especially, diffusion induced microcrack formation in brittle, intercalation active materials, with emphasis on the grain/grain-boundary (GB) level implications, has been fundamentally investigated based on a stochastic modeling approach. Quasistatic damage evolution has been analyzed under lithium concentration gradient induced stress. Scaling of total amount of microcrack formation shows a power law variation with respect to the system size. Difference between the global and local roughness exponent indicates the existence of anomalous scaling. The deterioration of stiffness with respect to microcrack density displays two distinct regions of damage propagation; namely, diffused damage evolution and stress concentration driven localized crack propagation. Polycrystalline material microstructures with different grain sizes have been considered to study the diffusion-induced fracture in grain and GB regions. Intergranular crack paths are observed within microstructures containing softer GB region, whereas, transgranular crack paths have been observed in microstructures with relatively strong GB region. Increased tortuosity of the spanning crack has been attributed as the reason behind attaining increased fracture strength in polycrystalline materials with smaller grain sizes.

  9. Scaling law of average failure rate and steady-state rate in rocks

    NASA Astrophysics Data System (ADS)

    Hao, Shengwang; Liu, Chao; Wang, Yingchong; Chang, Fuqing

    2017-03-01

    The evolution properties in the steady stage of a rock specimen are reflective of the damage or weakening growth within and thus are used to determine whether an unstable transition occurs. In this paper, we report the experimental results for rock (granite and marble) specimens tested at room temperature and room humidity under three typical loading modes: quasi-static monotonic loading, brittle creep, and brittle creep relaxation. Deformed rock specimens in current experiments exhibit an apparent steady stage characterized by a nearly constant evolution rate, which dominates the lifetime of the rock specimens. The average failure rate presents a common power-law relationship with the evolution rate in the steady stage, although the exponent is different for different loading modes. The results indicate that a lower ratio of the slope of the secondary stage with respect to the average rate of the entire lifetime implies a more brittle failure.

  10. Undermining Evolution: Where State Standards Go Wrong

    ERIC Educational Resources Information Center

    American Educator, 2012

    2012-01-01

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

  11. Analysis of Microstructure and Damage Evolution in Ultra-Thin Wires of the Magnesium Alloy MgCa0.8 at Multipass Drawing

    NASA Astrophysics Data System (ADS)

    Milenin, Andrij; Kustra, Piotr; Byrska-Wójcik, Dorota; Grydin, Olexandr; Schaper, Mirko; Mentlein, Thorben; Gerstein, Gregory; Nürnberger, Florian

    2016-12-01

    A combined multipass hot and cold drawing process was implemented to manufacture ultra-thin wires of the magnesium alloy MgCa0.8 with a final diameter of 0.05 mm. Numerical simulations were applied to design the drawing process of 40 passes regarding the microstructure evolution. To parametrize the model, in situ tensile tests were performed. Analysis of the MgCa0.8 wires featuring diameters below 0.1 mm revealed no intergranular crack initiation. The grain size of the ultra-thin wires is within the range of 30-500 nm with grains elongated in the drawing direction. The fine-grained microstructure provides high mechanical strength properties.

  12. 45 CFR 164.412 - Law enforcement delay.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... § 164.412 Law enforcement delay. If a law enforcement official states to a covered entity or business... 45 Public Welfare 1 2010-10-01 2010-10-01 false Law enforcement delay. 164.412 Section 164.412... investigation or cause damage to national security, a covered entity or business associate shall: (a) If...

  13. 46 CFR 390.12 - Liquidated damages.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Liquidated damages. 390.12 Section 390.12 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION REGULATIONS UNDER PUBLIC LAW 91-469 CAPITAL... which by operation of law must be withdrawn from the capital account balance on deposit in the fund...

  14. Conservation Laws

    NASA Astrophysics Data System (ADS)

    Dewitt, Bryce; Christensen, Steven M.

    In the case of the free particle, we interpreted various components of the energy-momentum-stress density as fluxes of energy and momentum. This interpretation can obviously be extended also to particle ensembles and gases. When we speak of fluxes we usually think of quantities that are conserved. In special relativity, energy and momentum are conserved. In general relativity, they are no longer generally conserved, at least if we do not include the energy and momentum of the gravitational field itself. Nevertheless, their densities and fluxes satisfy a covariant generalization of a true conservation law, which is quite easy to obtain.

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

    NASA Astrophysics Data System (ADS)

    Hayakawa, Kunio; Nakamura, Tamotsu; Tanaka, Shigekazu

    2007-05-01

    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.

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

    PubMed Central

    Lan, Chunguang; Zhou, Zhi; Ou, Jinping

    2012-01-01

    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

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

    PubMed

    Lan, Chunguang; Zhou, Zhi; Ou, Jinping

    2012-01-01

    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.

  18. Flexure with damage

    NASA Astrophysics Data System (ADS)

    Manaker, David M.; Turcotte, Donald L.; Kellogg, Louise H.

    2006-09-01

    Ductile behaviour in rocks is often associated with plasticity due to dislocation motion or diffusion under high pressures and temperatures. However, ductile behaviour can also occur in brittle materials. An example would be cataclastic flow associated with folding at shallow crustal levels. Engineers utilize damage mechanics to model the continuum deformation of brittle materials. In this paper we utilize a modified form of damage mechanics that includes a yield stress. Here, damage represents a reduction in frictional strength. We use this empirical approach to simulate bending of the lithosphere through the problem of plate flexure. We use numerical simulations to obtain quasi-static solutions to the Navier equations of elasticity. We use the program GeoFEST v. 4.5 (Geophysical Finite Element Simulation Tool), developed by NASA Jet Propulsion Laboratory, to generate solutions for each time step. When the von Mises stress exceeds the critical stress on an element we apply damage to reduce the shear modulus of the element. Damage is calculated at each time step by a power-law relationship of the ratio of the critical stress to the von Mises stress and the critical strain to the von Mises strain. This results in the relaxation of the material due to increasing damage. To test our method, we apply our damage rheology to a semi-infinite plate deforming under its own weight. Where the von Mises stress exceeds the critical stress, we simulate the formation of damage and observe the time-dependent relaxation of the stress and strain to near the yield strength. We simulate a wide range of behaviours from slow relaxation to instantaneous failure, over timescales that span six orders of magnitude. Using this method, stress relaxation produces perfectly plastic behaviour in cases where failure does not occur. For cases of failure, we observe a rapid increase in damage, analogous to the acceleration of microcrack formation and acoustic emissions prior to failure. Thus

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

    ERIC Educational Resources Information Center

    Wixted, John T.

    2004-01-01

    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…

  20. Effect of the order of He+ and H+ ion co-implantation on damage generation and thermal evolution of complexes, platelets, and blisters in silicon

    NASA Astrophysics Data System (ADS)

    Daghbouj, N.; Cherkashin, N.; Darras, F.-X.; Paillard, V.; Fnaiech, M.; Claverie, A.

    2016-04-01

    Hydrogen and helium co-implantation is nowadays used to efficiently transfer thin Si layers and fabricate silicon on insulator wafers for the microelectronic industry. The synergy between the two implants which is reflected through the dramatic reduction of the total fluence needed to fracture silicon has been reported to be strongly influenced by the implantation order. Contradictory conclusions on the mechanisms involved in the formation and thermal evolution of defects and complexes have been drawn. In this work, we have experimentally studied in detail the characteristics of Si samples co-implanted with He and H, comparing the defects which are formed following each implantation and after annealing. We show that the second implant always ballistically destroys the stable defects and complexes formed after the first implant and that the redistribution of these point defects among new complexes drives the final difference observed in the samples after annealing. When H is implanted first, He precipitates in the form of nano-bubbles and agglomerates within H-related platelets and nano-cracks. When He is implanted first, the whole He fluence is ultimately used to pressurize H-related platelets which quickly evolve into micro-cracks and surface blisters. We provide detailed scenarios describing the atomic mechanisms involved during and after co-implantation and annealing which well-explain our results and the reasons for the apparent contradictions reported at the state of the art.

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

    PubMed

    Alberti, C

    2012-02-01

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

  2. Guess-Work and Reasonings on Centennial Evolution of Surface Air Temperature in Russia. Part IV: Towards Economic Estimations of Climate-Related Damages from the Bifurcation Analysis Viewpoint

    NASA Astrophysics Data System (ADS)

    Kolokolov, Yury; Monovskaya, Anna

    The paper completes the cycle of the research devoted to the development of the experimental bifurcation analysis (not computer simulations) in order to answer the following questions: whether qualitative changes occur in the dynamics of local climate systems in a centennial timescale?; how to analyze such qualitative changes with daily resolution for local and regional space-scales?; how to establish one-to-one daily correspondence between the dynamics evolution and economic consequences for productions? To answer the questions, the unconventional conceptual model to describe the local climate dynamics was proposed and verified in the previous parts. That model (HDS-model) originates from the hysteresis regulator with double synchronization and has a variable structure due to competition between the amplitude quantization and the time quantization. The main advantage of the HDS-model is connected with the possibility to describe “internally” (on the basis of the self-regulation) the specific causal effects observed in the dynamics of local climate systems instead of “external” description of three states of the hysteresis behavior of climate systems (upper, lower and transient states). As a result, the evolution of the local climate dynamics is based on the bifurcation diagrams built by processing the data of meteorological observations, where the strange effects of the essential interannual daily variability of annual temperature variation are taken into account and explained. It opens the novel possibilities to analyze the local climate dynamics taking into account the observed resultant of all internal and external influences on each local climate system. In particular, the paper presents the viewpoint on how to estimate economic damages caused by climate-related hazards through the bifurcation analysis. That viewpoint includes the following ideas: practically each local climate system is characterized by its own time pattern of the natural qualitative

  3. In-situ luminescence monitoring of ion-induced damage evolution in SiO2 and Al2O3

    SciTech Connect

    Crespillo, Miguel L.; Graham, Joseph T.; Zhang, Yanwen; Weber, William J.

    2015-12-17

    Real-time, in-situ ionoluminescence measurements provide information of evolution of emission bands with ion fluence, and thereby establish a correlation between point defect kinetics and phase stability. Using fast light ions (2 MeV H and 3.5 He MeV) and medium mass-high energy ions (8 MeV O, E=0.5 MeV/amu), scintillation materials of a-SiO2, crystalline quartz, and Al2O3 are comparatively investigated at room temperature with the aim of obtaining a further insight on the structural defects induced by ion irradiation and understand the role of electronic energy loss on the damage processes. For more energetic heavy ions, the electronic energy deposition pattern offers higher rates of excitation deeper into the material and allows to evaluate the competing mechanisms between the radiative and non-radiative de-excitation processes. Irradiations with 8 MeV O ions have been selected corresponding to the electronic stopping regime, where the electronic stopping power is dominant, and above the critical amorphization threshold for quartz. Lastly, the usefulness of IBIL and its specific capabilities as a sensitive tool to investigate the material characterization and evaluation of radiation effects are demonstrated.

  4. Scaling Relations for Intercalation Induced Damage in Electrodes

    SciTech Connect

    Chen, Chien-Fan; Barai, Pallab; Smith, Kandler; Mukherjee, Partha P.

    2016-04-02

    Mechanical degradation, owing to intercalation induced stress and microcrack formation, is a key contributor to the electrode performance decay in lithium-ion batteries (LIBs). The stress generation and formation of microcracks are caused by the solid state diffusion of lithium in the active particles. Here in this work, scaling relations are constructed for diffusion induced damage in intercalation electrodes based on an extensive set of numerical experiments with a particle-level description of microcrack formation under disparate operating and cycling conditions, such as temperature, particle size, C-rate, and drive cycle. The microcrack formation and evolution in active particles is simulated based on a stochastic methodology. A reduced order scaling law is constructed based on an extensive set of data from the numerical experiments. The scaling relations include combinatorial constructs of concentration gradient, cumulative strain energy, and microcrack formation. Lastly, the reduced order relations are further employed to study the influence of mechanical degradation on cell performance and validated against the high order model for the case of damage evolution during variable current vehicle drive cycle profiles.

  5. Scaling Relations for Intercalation Induced Damage in Electrodes

    SciTech Connect

    Chen, Chien-Fan; Barai, Pallab; Smith, Kandler; Mukherjee, Partha P.

    2016-06-01

    Mechanical degradation, owing to intercalation induced stress and microcrack formation, is a key contributor to the electrode performance decay in lithium-ion batteries (LIBs). The stress generation and formation of microcracks are caused by the solid state diffusion of lithium in the active particles. In this work, scaling relations are constructed for diffusion induced damage in intercalation electrodes based on an extensive set of numerical experiments with a particle-level description of microcrack formation under disparate operating and cycling conditions, such as temperature, particle size, C-rate, and drive cycle. The microcrack formation and evolution in active particles is simulated based on a stochastic methodology. A reduced order scaling law is constructed based on an extensive set of data from the numerical experiments. The scaling relations include combinatorial constructs of concentration gradient, cumulative strain energy, and microcrack formation. The reduced order relations are further employed to study the influence of mechanical degradation on cell performance and validated against the high order model for the case of damage evolution during variable current vehicle drive cycle profiles.

  6. Scaling Relations for Intercalation Induced Damage in Electrodes

    DOE PAGES

    Chen, Chien-Fan; Barai, Pallab; Smith, Kandler; ...

    2016-04-02

    Mechanical degradation, owing to intercalation induced stress and microcrack formation, is a key contributor to the electrode performance decay in lithium-ion batteries (LIBs). The stress generation and formation of microcracks are caused by the solid state diffusion of lithium in the active particles. Here in this work, scaling relations are constructed for diffusion induced damage in intercalation electrodes based on an extensive set of numerical experiments with a particle-level description of microcrack formation under disparate operating and cycling conditions, such as temperature, particle size, C-rate, and drive cycle. The microcrack formation and evolution in active particles is simulated based onmore » a stochastic methodology. A reduced order scaling law is constructed based on an extensive set of data from the numerical experiments. The scaling relations include combinatorial constructs of concentration gradient, cumulative strain energy, and microcrack formation. Lastly, the reduced order relations are further employed to study the influence of mechanical degradation on cell performance and validated against the high order model for the case of damage evolution during variable current vehicle drive cycle profiles.« less

  7. Demonstrating the Gas Laws.

    ERIC Educational Resources Information Center

    Holko, David A.

    1982-01-01

    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.…

  8. Inclusion and the Law.

    ERIC Educational Resources Information Center

    Damer, Linda K.

    2001-01-01

    Describe four different laws related to the education of children with disabilities: (1) Public Law 94-142; (2) Public Law 99-457; (3) Public Law 101-336 ADA; and (4) Public Law 101-476 IDEA. Discusses the topic of mainstreaming and highlights the recent legal decisions that have occurred. (CMK)

  9. Prolegomenon to patterns in evolution.

    PubMed

    Kauffman, Stuart A

    2014-09-01

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

  10. Thermodynamical Arguments Against Evolution

    NASA Astrophysics Data System (ADS)

    Rosenhouse, Jason

    2017-02-01

    The argument that the second law of thermodynamics contradicts the theory of evolution has recently been revived by anti-evolutionists. In its basic form, the argument asserts that whereas evolution implies that there has been an increase in biological complexity over time, the second law, a fundamental principle of physics, shows this to be impossible. Scientists have responded primarily by noting that the second law does not rule out increases in complexity in open systems, and since the Earth receives energy from the Sun, it is an open system. This reply is correct as far as it goes, and it adequately rebuts the most crude versions of the second law argument. However, it is insufficient against more sophisticated versions, and it leaves many relevant aspects of thermodynamics unexplained. We shall consider the history of the argument, explain the nuances various anti-evolution writers have brought to it, and offer thorough explanations for why the argument is fallacious. We shall emphasize in particular that the second law is best viewed as a mathematical statement. Since anti-evolutionists never make use of the mathematical structure of thermodynamics, invocations of the second law never contribute anything substantive to their discourse.

  11. Molecular dynamics simulation of radiation damage cascades in diamond

    SciTech Connect

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

    2015-06-28

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

  12. Teaching Global Law.

    ERIC Educational Resources Information Center

    Wojtan, Linda S.

    1980-01-01

    Addresses problem of American students' limited knowledge of international issues and laws. Provides articles for secondary school students on law around the world, South Africa, Russia, folk law, and alternatives to the adversary system and suggests relevant resources. (KC)

  13. Right Hemisphere Brain Damage

    MedlinePlus

    ... Language and Swallowing / Disorders and Diseases Right Hemisphere Brain Damage [ en Español ] What is right hemisphere brain ... right hemisphere brain damage ? What is right hemisphere brain damage? Right hemisphere brain damage (RHD) is damage ...

  14. Innovations in Law.

    ERIC Educational Resources Information Center

    Martz, Carlton

    2000-01-01

    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…

  15. Students and the Law.

    ERIC Educational Resources Information Center

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

    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…

  16. Tax Law System

    ERIC Educational Resources Information Center

    Tsindeliani, Imeda A.

    2016-01-01

    The article deals with consideration of the actual theoretic problems of the subject and system of tax law in Russia. The theoretical approaches to determination of the nature of separate institutes of tax law are represented. The existence of pandect system intax law building as financial law sub-branch of Russia is substantiated. The goal of the…

  17. Toxic torts and environmental law: Recent developments

    SciTech Connect

    Mahoney, W.F.; Murphy, J.; Cross, A.

    1994-12-31

    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.

  18. America's Anti-Evolution Movement

    ERIC Educational Resources Information Center

    Moore, Randy

    2002-01-01

    Evolution is the cornerstone of biology and one of the most powerful, exciting, and well-supported laws in modern science. Evolution transforms biology from a collection of unrelated observations and definitions into a coherent discipline that, among other things, helps people understand life's history and predict answers to important research…

  19. Evolution and Friendship

    ERIC Educational Resources Information Center

    Mena-Werth, Jose

    2005-01-01

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

  20. Incorporating Micro-Mechanics Based Damage Models into Earthquake Rupture Simulations

    NASA Astrophysics Data System (ADS)

    Bhat, H.; Rosakis, A.; Sammis, C. G.

    2012-12-01

    The micromechanical damage mechanics formulated by Ashby and Sammis, 1990 and generalized by Deshpande and Evans 2008 has been extended to allow for a more generalized stress state and to incorporate an experimentally motivated new crack growth (damage evolution) law that is valid over a wide range of loading rates. This law is sensitive to both the crack tip stress field and its time derivative. Incorporating this feature produces additional strain-rate sensitivity in the constitutive response. The model is also experimentally verified by predicting the failure strength of Dionysus-Pentelicon marble over a wide range of strain rates. Model parameters determined from quasi-static experiments were used to predict the failure strength at higher loading rates. Agreement with experimental results was excellent. After this verification step the constitutive law was incorporated into a Finite Element Code focused on simulating dynamic earthquake ruptures with specific focus on the ends of the fault (fault tip process zone) and the resulting strong ground motion radiation was studied.

  1. The Distinction between Civil and Criminal Law: A Lesson Plan for High School Law-Related Educators To Support "Understanding the Federal Courts."

    ERIC Educational Resources Information Center

    Administrative Office of the United States Courts, Washington, DC.

    The O. J. Simpson trials taught much of the United States a basic lesson in the difference between criminal law and civil law. Many students learn in their government classes that a person cannot be tried twice for the same crime. A person found innocent in a criminal trial, however, can be sued under civil law procedures for damages. It is…

  2. 48 CFR 222.302 - Liquidated damages and overtime pay.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... the Government as liquidated damages to the servicing finance and accounting officer for crediting to the appropriate Government Treasury account. The contracting officer shall return any excess withheld... REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE SOCIOECONOMIC PROGRAMS APPLICATION OF LABOR LAWS TO...

  3. 48 CFR 422.302 - Liquidated damages and overtime pay.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SOCIOECONOMIC PROGRAMS APPLICATION OF LABOR LAWS TO GOVERNMENT ACQUISITIONS Contract Work Hours and Safety... authorized to review determinations of liquidated damages due under section 104(c) of the Contract Work...

  4. Damaged Skylab

    NASA Technical Reports Server (NTRS)

    1973-01-01

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

  5. Administrative Law Judges

    EPA Pesticide Factsheets

    The Administrative Law Judges conduct hearings and render decisions in proceedings between the EPA and persons, businesses, government entities, and other organizations which are or are alleged to be regulated under environmental laws.

  6. Health care law versus constitutional law.

    PubMed

    Hall, Mark A

    2013-04-01

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

  7. Tort law and medical malpractice insurance premiums.

    PubMed

    Kilgore, Meredith L; Morrisey, Michael A; Nelson, Leonard J

    2006-01-01

    This paper estimated the effects of tort law and insurer investment returns on physician malpractice insurance premiums. Data were collected on tort law from 1991 through 2004, and multivariate regression models, including fixed effects for state and year, were used to estimate the effect of changes in tort law on medical malpractice premiums. The premium consequences of national policy changes were simulated. The analysis found that the introduction of a new damage cap lowered malpractice premiums for internal medicine, general surgery, and obstetrics/gynecology by 17.3%, 20.7%, and 25.5%, respectively. Lowering damage caps by dollar 100,000 reduced premiums by 4%. Statutes of repose also resulted in lower premiums. No other tort law changes had the effect of lowering premiums. Simulation results indicate that a national cap of dollar 250,000 on awards for noneconomic damages in all states would imply premium savings of dollar 16.9 billion. Extending a dollar 250,000 cap to all states that do not currently have them would save dollar 1.4 billion annually, or about 8% of the total. A negative effect on malpractice premiums was found for the Dow Jones industrial average, but not for bond prices; effects of the Nasdaq index were not significant for internal medicine, but were marginally significant for surgery and obstetrics premiums.

  8. Campus Common Law

    ERIC Educational Resources Information Center

    Bakken, Gordon Morris

    1976-01-01

    Discusses the legal principle of common law as it applies to the personnel policies of colleges and universities in an attempt to define the parameters of campus common law and to clarify its relationship to written university policies and relevant state laws. (JG)

  9. On Teaching Natural Law.

    ERIC Educational Resources Information Center

    Forte, David F.

    1978-01-01

    A brief look at Columbia, Harvard, and Notre Dame law schools shows that the American tradition in teaching natural law has not been strong. The value of teaching natural law is discussed, a separate course or seminar is seen as the most effective option, and a selection of available sources for such a course is appended. (JMD)

  10. School of Law

    ERIC Educational Resources Information Center

    Olsen, Ken

    2005-01-01

    This article explains how Street Law helps teachers to defuse tensions between students and police through a combination of education, empathy, and expertise. Street Law was born at Georgetown in 1972. Every year, it sends two dozen law students like Courtney Donovan into Washington, D.C., high schools to help teach the year long course. Street…

  11. Education on Environmental Law.

    ERIC Educational Resources Information Center

    Cano, Guillermo J.

    1981-01-01

    Argues that environmental law, as part of legal science, should be taught at universities; discusses the development of environmental law and its relationship to other sciences; and proposes a framework for studying environmental law as a university course for study. (DC)

  12. Henry's Law: A Retrospective

    ERIC Educational Resources Information Center

    Rosenberg, Robert M.; Peticolas, Warner L.

    2004-01-01

    A retrospective view of Henry's law and its applicability in any specific system at a finite concentration is tested. It can be concluded that Henry's law is only a limiting law and is adequate at low mole fractions but is useful for practical purposes where high precision is not required.

  13. The Laws Are Yours.

    ERIC Educational Resources Information Center

    Lawyers' Wives of Wisconsin, Racine.

    The pamphlet briefly describes various facets of the law and legal system in Wisconsin, and defines many legal terms. The objective is to further public understanding of the law and of the legal profession, particularly in Wisconsin. No attempt is made to answer specific legal questions. Sections cover civil and criminal law; the federal court…

  14. Cumulative creep damage for unidirectional composites under step loading

    NASA Astrophysics Data System (ADS)

    Guedes, Rui Miranda

    2012-11-01

    The creep lifetime prediction of unidirectional composite materials under step loading, based on constant loading durability diagram, is analyzed for the two-step creep loading condition. For this purpose different nonlinear cumulative-damage laws are revisited and applied to predict creep lifetime. One possible approach to accounting for damage accumulation is provided by the continuum-damage mechanics (CDM). However, the CDM lifetime expression obtained for constant loading condition presents some drawbacks. Specifically, the upper stress range is not accommodated by CDM form. A modification of CDM is proposed, forcing the CDM to capture the short-term creep failure. It is proven that this modified CDM (MCDM) does not yield the same predictions as the Linear Cumulative-damage law (Miner's law). Predictions obtained from the nonlinear cumulative-damage laws are compared against synthetic lifetime generated by a micromechanical model that simulates unidirectional composites under two-step creep loading condition. Comparable deviations from Miner's law are obtained by the nonlinear cumulative-damage laws.

  15. Is life law-like?

    PubMed

    Weiss, Kenneth M; Buchanan, Anne V

    2011-08-01

    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.

  16. Three Laws in Darwinian Evolutionary Theory

    NASA Astrophysics Data System (ADS)

    Ao, Ping

    2006-03-01

    Recent works to formulate laws in Darwinian evolutionary dynamics will be discussed. Specifically, three laws which form a consistent mathematical framework for the evolutionary dynamics in biology will be spelt out. The second law is most quantitative and is explicitly expressed in the unique form of a stochastic differential equation. Salient features of Darwinian evolutionary dynamics are captured by this law: the probabilistic nature of evolution, ascendancy, and the adaptive landscape. Four dynamical elements are introduced in this formulation: the ascendant matrix, the transverse matrix, the Wright evolutionary potential, and the stochastic drive. The first law may be regarded as a special case of the second law. It gives the reference point to discuss the evolutionary dynamics. The third law describes the relationship between the focused level of description to its lower and higher ones, and defines the dichotomy of deterministic and stochastic drives. It is an acknowledgement of the hierarchical structure in biology. A new interpretation of Fisher's fundamental theorem of natural selection is provided in terms of the F-Theorem. Ref. P. Ao, Physics of Life Reviews 2 (2005) 117-156.

  17. Approximation of Laws

    NASA Astrophysics Data System (ADS)

    Niiniluoto, Ilkka

    2014-03-01

    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).

  18. Dynamically driven phase transformations in heterogeneous materials. II. Applications including damage

    NASA Astrophysics Data System (ADS)

    Plohr, JeeYeon N.; Clements, B. E.; Addessio, F. L.

    2006-12-01

    A model, developed for heterogeneous materials undergoing dynamically driven phase transformations in its constituents, has been extended to include the evolution of damage. Damage is described by two mechanisms: interfacial debonding between the constituents and brittle failure micro-crack growth within the constituents. The analysis is applied to silicon carbide-titanium (SiC-Ti) unidirectional metal matrix composites that undergo the following phenomena: Ti has a yield stress of approximately 0.5 GPa and above a pressure of about 2 GPa undergoes a solid-solid phase transformation. The inelastic work from plastic dissipation contributes to the temperature and pressure rise in the Ti. SiC behaves elastically below a critical stress, above which it is damaged by microcrack growth. Finally, under tensile loading, the interface between Ti and SiC debonds according to an interfacial decohesion law. Each process is first examined independently in order to understand how its characteristic behavior is manifested in the stress-strain response of the composite. The complex interplay between loading states, viscoplasticity, damage, and solid-solid phase transformations is then studied at both the micromechanics and macromechanics levels.

  19. Applying laws of biology to diabetes with emphasis on metabolic syndrome.

    PubMed

    Houck, Philip D; de Oliveira, Jose Mario F

    2013-05-01

    The listed laws of biology will be applied to diabetes mellitus and metabolic syndrome. (1) Biology must be consistent with the fundamental laws of physics and chemistry. (2) Life, as opposed to non-living, exhibits negative entropy (known as syntropy), capable of creating order out of chaos. (The energy to support negative entropy is yet to be defined.) (3) The cell is the fundamental unit of biology. (4) The cell must be in homeostasis with its environment. (This property enables the process of evolution. In other words, the environment changes life.) (5) There must be a distinction between self and the environment. (Immunity and inflammation are the defenses against invaders from the environment and responsible for repair of damaged and senile cells.) (6) Electromagnetic information transfer is necessary for development and regeneration. (Life and, more specifically, regeneration of tissue will not exist in a non-electromagnetic environment, denervation results in atrophy.) A new model of disease derived from these laws is that health exists when degeneration and regeneration are in balance. Inflammation is the fulcrum between the two, being both beneficial in repair and detrimental by promoting degeneration. This model leads to a number of hypotheses.

  20. 32 CFR 750.48 - Measure of damages in injury or death cases.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... possessions, determine the measure of damages under the law of the location where the injury arises. (b) Where... provision, damages will be determined in accordance with general principles of American tort law. The..., loss of companionship, comfort, society, protection, and consortium, and loss of training,...

  1. Fatigue Life of Postbuckled Structures with Indentation Damages

    NASA Technical Reports Server (NTRS)

    Davila, Carlos G.; Bisagni, Chiara

    2016-01-01

    The fatigue life of composite stiffened panels with indentation damage was investigated experimentally using single stringer compression specimens. Indentation damage was induced on one of the two flanges of each stringer. The experiments were conducted using advanced instrumentation, including digital image correlation, passive thermography, and in-situ ultrasonic scanning. Specimens with initial indentation damage lengths of 32 millimeters to 56 millimeters were tested quasi-statically and in fatigue, and the effects of cyclic load amplitude and damage size were studied. A means of comparison of the damage propagation rates and collapse loads based on a stress intensity measure and the Paris law is proposed.

  2. Fatigue Life of Postbuckled Structures with Indentation Damage

    NASA Technical Reports Server (NTRS)

    Davila, Carlos G.; Bisagni, Chiara

    2016-01-01

    The fatigue life of composite stiffened panels with indentation damage was investigated experimentally using single stringer compression specimens. Indentation damage was induced on one of the two flanges of the stringer. The experiments were conducted using advanced instrumentation, including digital image correlation, passive thermography, and in-situ ultrasonic scanning. Specimens with initial indentation damage lengths of 37 millimeters to 56 millimeters were tested in fatigue and the effects of cyclic load amplitude and damage size were studied. A means of comparison of the damage propagation rates and collapse loads based on a stress intensity measure and the Paris law is proposed.

  3. Macrothermodynamics of Biological Evolution:

    NASA Astrophysics Data System (ADS)

    Gladyshev, Georgi P.

    The author sets forth general considerations pertaining to the thermodynamic theory of biological evolution and the aging of living organisms. It becomes much easier to comprehend the phenomenon of life scrutinizing the formation of structural hierarchies of biological matter applying different temporal scales. These scales are 'identified' by nature itself, and this is reflected in the law of temporal hierarchies. The author discusses some misunderstandings in thermodynamics and evolutionary biology. A simple physicochemical model of biological evolution and the development of living beings is proposed. The considered theory makes it possible to use physicochemical evaluations to develop effective anti-aging diets.

  4. Helmholtz solitons in power-law optical materials

    SciTech Connect

    Christian, J. M.; McDonald, G. S.; Potton, R. J.; Chamorro-Posada, P.

    2007-09-15

    A nonlinear Helmholtz equation for optical materials with regimes of power-law type of nonlinearity is proposed. This model captures the evolution of broad beams at any angle with respect to the reference direction in a wide range of media, including some semiconductors, doped glasses, and liquid crystals. Exact analytical soliton solutions are presented for a generic nonlinearity, within which known Kerr solitons comprise a subset. Three general conservation laws are also reported. Analysis and numerical simulations examine the stability of the Helmholtz power-law solitons. A propagation feature, associated with spatial solitons in power-law media, constituting a class of oscillatory solution, is identified.

  5. On Hack's Law

    NASA Astrophysics Data System (ADS)

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

    1996-11-01

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

  6. Zipf's law, power laws and maximum entropy

    NASA Astrophysics Data System (ADS)

    Visser, Matt

    2013-04-01

    Zipf's law, and power laws in general, have attracted and continue to attract considerable attention in a wide variety of disciplines—from astronomy to demographics to software structure to economics to linguistics to zoology, and even warfare. A recent model of random group formation (RGF) attempts a general explanation of such phenomena based on Jaynes' notion of maximum entropy applied to a particular choice of cost function. In the present paper I argue that the specific cost function used in the RGF model is in fact unnecessarily complicated, and that power laws can be obtained in a much simpler way by applying maximum entropy ideas directly to the Shannon entropy subject only to a single constraint: that the average of the logarithm of the observable quantity is specified.

  7. The evolution of airplanes

    NASA Astrophysics Data System (ADS)

    Bejan, A.; Charles, J. D.; Lorente, S.

    2014-07-01

    The prevailing view is that we cannot witness biological evolution because it occurred on a time scale immensely greater than our lifetime. Here, we show that we can witness evolution in our lifetime by watching the evolution of the flying human-and-machine species: the airplane. We document this evolution, and we also predict it based on a physics principle: the constructal law. We show that the airplanes must obey theoretical allometric rules that unite them with the birds and other animals. For example, the larger airplanes are faster, more efficient as vehicles, and have greater range. The engine mass is proportional to the body size: this scaling is analogous to animal design, where the mass of the motive organs (muscle, heart, lung) is proportional to the body size. Large or small, airplanes exhibit a proportionality between wing span and fuselage length, and between fuel load and body size. The animal-design counterparts of these features are evident. The view that emerges is that the evolution phenomenon is broader than biological evolution. The evolution of technology, river basins, and animal design is one phenomenon, and it belongs in physics.

  8. Public health law reform.

    PubMed

    Gostin, L O

    2001-09-01

    Public health law reform is necessary because existing statutes are outdated, contain multiple layers of regulation, and are inconsistent. A model law would define the mission and functions of public health agen cies, provide a full range of flexible powers, specify clear criteria and procedures for activities, and provide protections for privacy and against discrimination. The law reform process provides an opportunity for public health agencies to draw attention to their resource needs and achievements and to form ties with constituency groups and enduring relations with the legislative branch of government. Ultimately, the law should become a catalyst, rather than an impediment, to reinvigorating the public health system.

  9. Public Health Law Reform

    PubMed Central

    Gostin, Lawrence O.

    2001-01-01

    Public health law reform is necessary because existing statutes are outdated, contain multiple layers of regulation, and are inconsistent. A model law would define the mission and functions of public health agencies, provide a full range of flexible powers, specify clear criteria and procedures for activities, and provide protections for privacy and against discrimination. The law reform process provides an opportunity for public health agencies to draw attention to their resource needs and achievements and to form ties with constituency groups and enduring relations with the legislative branch of government. Ultimately, the law should become a catalyst, rather than an impediment, to reinvigorating the public health system. PMID:11527757

  10. Darwinian Evolution and Fractals

    NASA Astrophysics Data System (ADS)

    Carr, Paul H.

    2009-05-01

    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!

  11. School Law Update...Preventive School Law.

    ERIC Educational Resources Information Center

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

    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…

  12. Brittle creep, damage, and time to failure in rocks

    NASA Astrophysics Data System (ADS)

    Amitrano, David; Helmstetter, AgnèS.

    2006-11-01

    We propose a numerical model based on static fatigue laws in order to model the time-dependent damage and deformation of rocks under creep. An empirical relation between time to failure and applied stress is used to simulate the behavior of each element of our finite element model. We review available data on creep experiments in order to study how the material properties and the loading conditions control the failure time. The main parameter that controls the failure time is the applied stress. Two commonly used models, an exponential tf-exp (-bσ/σ0) and a power law function tf-σb' fit the data as well. These time-to-failure laws are used at the scale of each element to simulate its damage as a function of its stress history. An element is damaged by decreasing its Young's modulus to simulate the effect of increasing crack density at smaller scales. Elastic interactions between elements and heterogeneity of the mechanical properties lead to the emergence of a complex macroscopic behavior, which is richer than the elementary one. In particular, we observe primary and tertiary creep regimes associated respectively with a power law decay and increase of the rate of strain, damage event and energy release. Our model produces a power law distribution of damage event sizes, with an average size that increases with time as a power law until macroscopic failure. Damage localization emerges at the transition between primary and tertiary creep, when damage rate starts accelerating. The final state of the simulation shows highly damaged bands, similar to shear bands observed in laboratory experiments. The thickness and the orientation of these bands depend on the applied stress. This model thus reproduces many properties of rock creep, which were previously not modeled simultaneously.

  13. [Common law, civil law: thinking about the tools of the judge in bioethics].

    PubMed

    Baudouin, Jean-Louis

    2006-01-01

    Civilian and common law judges differ substantially in their approach to the resolution of issues concerning bioethics and health sciences. Whereas the civilian judge will first take into account the legislative source, his common law counterpart will most probably first look at judicial precedents for guidance. In both systems, however, the legislative drafting technique differs substantially and has a direct impact on judicial interpretation of the law. Both systems also differ in the way that judicial decisions are drafted and rendered. In the common law tradition, judges draft their own opinion, leaving the possibility of dissent which, in turn, helps to better illustrate contentious issues and may have an influence on social awareness of difficult problems. Finally, in bioethics, legislation should be preferred if only for a question of social legitimacy, since decisions are then taken by elected representatives. However, this type of legislation should be subject to periodical review to better adapt its rules to the evolution of science and society.

  14. [Law 6/84: "an inappropriate law"].

    PubMed

    Barroco, L E

    1994-01-01

    The intervention of Dr. Luis Elmano Barroco was evaluated at a meeting on March 19, 1994, on the topic of the state of abortion after 10 years of the new abortion law. Some aspects of the law of 1984 are characterized as inappropriate and inadequate because of the experience of the maternity ward of Dr. Alfredo da Costa. It was expected that in the wake of the publication of the law, official health care institutions would provide services for termination of pregnancy in accordance with legal indications. However, a survey carried out by the Association for Family Planning in July 1993 revealed that more than 50% of hospitals did not perform abortions because of the inexistence of specialized services or lack of resources or on grounds of conscientious objection. Even a revision of the abortion law does not take into consideration the fact that before 12 weeks of gestation it is difficult to precisely confirm grave lesions or the physical and psychological state of health of the pregnant woman which could be potentially life threatening. It was not taken into account either that it is impossible to diagnose definitively chromosomal aberrations, severe diseases, and fetal malformation before the 16th week. The law did not contemplate the prevailing socioeconomical conditions either that lead to clandestine abortion with high morbidity and mortality from cervical lesions, uterine perforation, infections, sepsis, and salpingitis. Prenatal diagnosis for eugenic abortion can be carried out by cytogenetic analysis of the amniotic fluid and ecography, but such diagnosis probably amounts to only 30-40% of risk cases in the whole country. A recent study by the Johns Hopkins University indicated that the chance of survival of a child born before 24 weeks is nil, therefore the limit of induced abortion should be extended to the 24th week to facilitate diagnosis of possible genetic abnormalities.

  15. The Law of Elasticity

    ERIC Educational Resources Information Center

    Cocco, Alberto; Masin, Sergio Cesare

    2010-01-01

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

  16. School Law Update, 1986.

    ERIC Educational Resources Information Center

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

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

  17. Careers in Law Enforcement.

    ERIC Educational Resources Information Center

    Herbert, Solomon J.

    1991-01-01

    Opportunities for blacks in law enforcement careers are detailed. Local and federal law enforcement agencies are hiring members of minority groups. In a climate in which so many young African Americans are involved in negative behaviors, others should take the opportunity to try to provide positive role models. (SLD)

  18. The Corporate Law Curriculum

    ERIC Educational Resources Information Center

    Mofsky, James S.

    1976-01-01

    On the premise that corporate counsel must be an able diagnostician before he can focus on highly specialized and interrelated issues of business law, the author suggests an approach to corporate law curriculum in which the basic course balances the quality and quantity of material designed to create the needed sensitivity. (JT)

  19. Know Your Laws. Czechoslovakian.

    ERIC Educational Resources Information Center

    Watson, Joan Q.; Ziembinski, Vera

    This Czechoslovakian 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…

  20. Know Your Laws. Italian.

    ERIC Educational Resources Information Center

    Watson, Joan Q.

    This Italian language version of "Know Your Laws" consists of 24 self-contained modules designed to acquaint the Florida adult students with law they 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…

  1. Know Your Laws. French.

    ERIC Educational Resources Information Center

    Watson, Joan Q.; Ledun, Andree

    This French 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…

  2. Know Your Laws. German.

    ERIC Educational Resources Information Center

    Watson, Joan Q.; Karch, Hannelore

    This German 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…

  3. Know Your Laws. Spanish.

    ERIC Educational Resources Information Center

    Watson, Joan Q.; Ackerson, Leonor

    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…

  4. Know Your Laws. Polish.

    ERIC Educational Resources Information Center

    Watson, Joan Q.; Kopania, Margaret

    This Polish 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…

  5. California Library Laws, 2009

    ERIC Educational Resources Information Center

    Smith, Paul G., Ed.

    2009-01-01

    California Library Laws 2009 is a selective guide to state laws and related materials that most directly affect the everyday operations of public libraries and organizations that work with public libraries. It is intended as a convenient reference, not as a replacement for the annotated codes or for legal advice. The guide is organized as follows.…

  6. California Library Laws, 2008

    ERIC Educational Resources Information Center

    Smith, Paul G., Ed.

    2008-01-01

    "California Library Laws 2008" is a selective guide to state laws and related materials that most directly affect the everyday operations of public libraries and organizations that work with public libraries. It is intended as a convenient reference, not as a replacement for the annotated codes or for legal advice. The guide is organized…

  7. Laws for Young Mountaineers.

    ERIC Educational Resources Information Center

    Kanawha County Board of Education, Charleston, WV.

    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,…

  8. Teaching Information Technology Law

    ERIC Educational Resources Information Center

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

    2009-01-01

    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…

  9. Science and the Law.

    ERIC Educational Resources Information Center

    Kennedy, Donald; Merrill, Richard A.

    2000-01-01

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

  10. Pop Goes the Law

    ERIC Educational Resources Information Center

    Harper, Steven J.

    2013-01-01

    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…

  11. Language and the Law.

    ERIC Educational Resources Information Center

    Gibbons, John

    1999-01-01

    Discusses the language of law and its general interest to the field of applied linguistics. Specific focus is on legal language, the problems and remedies of legal communication (e.g., language and disadvantage before the law, improving legal communication) the legislation of language (e.g., language rights, language crimes), and forensic…

  12. Teachers and the Law.

    ERIC Educational Resources Information Center

    Fischer, Louis; And Others

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

  13. Bicycle Law Enforcement Manual.

    ERIC Educational Resources Information Center

    Hunter, William W.; Stutts, Jane C.

    This manual is an attempt to draw together relevant resources and information for localities interested in developing a bicycle law enforcement operation. It is divided into five major sections. Section I explains the need for and importance of bicycle law enforcement. In section II are presented examples of past and current bicycle law…

  14. Social Studies: Law Education.

    ERIC Educational Resources Information Center

    Curriculum Review, 1979

    1979-01-01

    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)

  15. Indian Law Enforcement History.

    ERIC Educational Resources Information Center

    Etheridge, David

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

  16. Reinventing Howard's Law School.

    ERIC Educational Resources Information Center

    Glenn, Gwendolyn

    2001-01-01

    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)

  17. Charles' Law of Gases.

    ERIC Educational Resources Information Center

    Petty, John T.

    1995-01-01

    Describes an experiment that uses air to test Charles' law. Reinforces the student's intuitive feel for Charles' law with quantitative numbers they can see, introduces the idea of extrapolating experimental data to obtain a theoretical value, and gives a physical quantitative meaning to the concept of absolute zero. (JRH)

  18. Law of Empires.

    ERIC Educational Resources Information Center

    Martz, Carlton

    2001-01-01

    This issue of "Bill of Rights in Action" explores issues raised by empires and imperial law. The first article, "Clash of Empires: The Fight for North America," looks at the clash of empires and the fight for North America during the 18th century. The second article, "When Roman Law Ruled the Western World," examines…

  19. Civil Law: 12 Activities.

    ERIC Educational Resources Information Center

    Dresbach, Debra

    These learning activities on civil law are intended to supplement the secondary level Scholastic materials "Living Law." Case studies, simulations, and role-play activities are included. Information provided for each activity includes a brief overview, background information, teacher instructions and a description of each activity.…

  20. EOS Laser Atmosphere Wind Sounder (LAWS) investigation

    NASA Technical Reports Server (NTRS)

    1996-01-01

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

  1. International resources law

    SciTech Connect

    Not Available

    1991-01-01

    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.

  2. Anisotropic damage effects in masonry walls

    NASA Astrophysics Data System (ADS)

    Massart, T.; Bouillard, P.; Geers, M. G. D.; Peerlings, R. H. J.

    2003-03-01

    This paper refers to the characterization of plane masonry behaviour under the assumption of plane stress. Masonry may be seen as a two-phase (bricks and mortar) periodic anisotropic material with complex macroscopic behaviour due to the possible occurrence of cracking in each of the phases. Non-linear constitutive equations have thus to be used in order to realistically represent masonry structures. Most existing macroscopic models defined for such materials are by essence phenomenological. This leads to weakly motivated frameworks and rather complex models, especially if one wants to account for material symmetry evolution due to cracking. The aim of this paper is to identify a simple set of damage mechanics variables for the constituents that could be used in homogenization procedures to infer the overall behaviour of the material from its mesostructural features (geometrical arrangement and mechanical properties of the constituents). Based on unit cell computations, it is shown that scalar damage mesomodels allow to obtain realistic damage patterns encountered in experiments. Results suggest that at the meso-scale, it is possible to use a scalar damage model for the individual phases which naturally leads to the desired anisotropy evolution into the macroscopic descriptions. This macroscopic anisotropy evolution is illustrated using a numerical homogenization procedure to identify the degraded stiffness associated to damage patterns. The influence of variations in the constituent characteristics is also correctly captured as illustrated for some of the loading schemes.

  3. Prospects for the international migration of U.S. sex offender registration and community notification laws.

    PubMed

    Logan, Wayne A

    2011-01-01

    Sex offender registration and community notification laws have proved enormously popular in the U.S. This is so even though the avowed sexual violence preventive benefits of the laws remain largely untested and unproven; indeed, it remains an open question whether the laws actually have anti-therapeutic and criminogenic effect. This article examines why this data deficit has characterized the social and political evolution of the laws and considers the prospects for their migration to other nations.

  4. Adhesive Characterization and Progressive Damage Analysis of Bonded Composite Joints

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  5. Chemical Laws, Idealization and Approximation

    ERIC Educational Resources Information Center

    Tobin, Emma

    2013-01-01

    This paper examines the notion of laws in chemistry. Vihalemm ("Found Chem" 5(1):7-22, 2003) argues that the laws of chemistry are fundamentally the same as the laws of physics they are all "ceteris paribus" laws which are true "in ideal conditions". In contrast, Scerri (2000) contends that the laws of chemistry are…

  6. Anomalous law of cooling

    NASA Astrophysics Data System (ADS)

    Lapas, Luciano C.; Ferreira, Rogelma M. S.; Rubí, J. Miguel; Oliveira, Fernando A.

    2015-03-01

    We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergoes a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton's law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature may oscillate. Despite this anomalous behavior, we show that the variation of entropy remains always positive in accordance with the second law of thermodynamics.

  7. Anomalous law of cooling.

    PubMed

    Lapas, Luciano C; Ferreira, Rogelma M S; Rubí, J Miguel; Oliveira, Fernando A

    2015-03-14

    We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergoes a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton's law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature may oscillate. Despite this anomalous behavior, we show that the variation of entropy remains always positive in accordance with the second law of thermodynamics.

  8. Lenz's Law Magic Trick

    NASA Astrophysics Data System (ADS)

    Ruiz, Michael J.

    2006-02-01

    The demonstration of Lenz's law by dropping a powerful magnet down a nonmagnetic metal pipe has become a classic lecture-hall demonstration.1,2 An inexpensive version is packaged as a professional magic trick3 called "Newton's Nightmare." Combining sleight-of-hand with a demonstration of Lenz's law is a surefire way to heighten student interest. The subsequent student discussion motivated by a desire to understand the magic trick can lead to a memorable physics lesson. This paper will discuss Lenz's law magic and review literature that reveals the subtlety of the physics.

  9. Anomalous law of cooling

    SciTech Connect

    Lapas, Luciano C.; Ferreira, Rogelma M. S.; Rubí, J. Miguel; Oliveira, Fernando A.

    2015-03-14

    We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergoes a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton’s law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature may oscillate. Despite this anomalous behavior, we show that the variation of entropy remains always positive in accordance with the second law of thermodynamics.

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

    NASA Astrophysics Data System (ADS)

    Grove, D. J.; Rajendran, A. M.

    1997-07-01

    The Rajendran-Grove (RG) ceramic damage model is based on an elastic-plastic-cracking description. A crack density parameter g (Na3) describes the scalar damage. The number of flaws N is assumed to be constant and the crack size parameter ``a'' evolves according to a strain energy release based evolution law. Crack orientation is not considered in this model. However, the microcracking multi-plane model considers crack orientations in nine pre-selected directions and computes damage by summing up the crack density contribution from all nine cracks. Both models account for crack opening and sliding. These two models have been implemented in the 1995 version of the EPIC code. We simulated an experiment in which an aluminum plate impacts a long slender ceramic bar. The experimental data consisted of particle velocities (in the radial direction) at two lateral locations on the surface of the bar and the particle velocity (in the longitudinal direction) at the back face of the bar. This paper compares the results from the EPIC code simulations using the RG and multi-plane ceramic models.

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

    NASA Astrophysics Data System (ADS)

    Grove, D. J.; Rajendran, A. M.

    1998-07-01

    The Rajendran-Grove (RG) ceramic damage model is based on an elastic-plastic-cracking description. A crack density parameter γ(=No*a3) describes the scalar damage. The number of flaws No* is assumed to be constant and the crack size parameter "a" evolves according to a strain energy release based evolution law. Crack orientation is not considered in this model. However, Espinosa's multi-plane (MP) microcracking model considers crack orientations in nine pre-selected directions and computes damage by summing up the crack density contribution from all nine directions. Both models account for crack opening and sliding. These two models have been implemented in the 1995 version of the EPIC code. We simulated plate impact experiments in which a thin alumina flyer plate impacted a thick alumina plate. The experimental data consisted of particle velocities recorded at the back face of the target plate. This paper compares the results from the EPIC code simulations using the RG and MP ceramic models.

  12. Equation of State of Phenomenological Mechanochemistry of Damage

    NASA Astrophysics Data System (ADS)

    Greenfield, Michael

    2015-06-01

    Traditional damage theory deals with distributed microcracks rather than with individual cracks. This theory adds just one additional parameter to the set of classical thermodynamic parameters of deformable solids, like strain and temperature. Basically, the traditional damage theory reflects only one experimental observation: the elastic modules become smaller with growing damage. Contrary to the traditional damage theory, the Phenomenological Mechanochemistry of Damage (PMD) includes, in addition to the bulk elastic energy, the energy associated with braking/recovery of chemical bonds. Therefore, in addition to the elasticity equations it includes the equation, describing evolution/dynamics of chemical bonds. Although ``chemical bonds'' is a nano-scale concept, we treat the bonds using phenomenological approach. The additional equation of damage evolution is of the rate type, thus, making the whole model rate-dependent (even in quasi-static approach.) In the paper, we review some earlier results and present the novel ones with emphasis on the rate-dependent effects.

  13. Accepting Evolution or Discarding Science

    ERIC Educational Resources Information Center

    Sharpes, Donald K.; Peramas, Mary M.

    2006-01-01

    Challenging basic principles of constitutional law, advocates of intelligent design are undermining educators' ability to teach evolution in their science classrooms. Because US Supreme Court rulings now prohibit creationist accounts of the origin of life in schools, arguments favoring divine intervention, known as intelligent design, have emerged…

  14. Evolution: geometrical and dynamical aspects.

    PubMed

    Freguglia, Paolo; Bazzani, Armando

    2003-01-01

    We develop a possible axiomatic approach to the evolution theory that has been previously discussed in Freguglia [2002]. The axioms synthesize the fundamental ideas of evolution theory and allow a geometrical and dynamical interpretation of the generation law. Using the axioms we derive a simple reaction-diffusion model which introduces the species as self-organized stationary distribution of a finite population and simulates the evolution of a phenotypic character under the effect of an external perturbing action. The dynamical properties of the model are briefly presented using numerical simulations.

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

    ERIC Educational Resources Information Center

    Costonis, John J.

    2002-01-01

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

  16. Plate tectonics, damage and inheritance.

    PubMed

    Bercovici, David; Ricard, Yanick

    2014-04-24

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

  17. Tribal Laws and Regulations

    EPA Pesticide Factsheets

    EPA works collaboratively with tribes, states, and local governments to preserve our land. A number of federal statutes or laws form the legal basis for the Office of Solid Waste and Emergency Response programs.

  18. Preventive Law on Campus.

    ERIC Educational Resources Information Center

    Ward, Paul; Tribbensee, Nancy

    2003-01-01

    Discusses how, by fostering a teamwork relationship between administrators and university attorneys, the preventive law approach can effectively identify risks and develop strategies and policies in advance of any individual legal dispute. (EV)

  19. Teaching Criminal Law.

    ERIC Educational Resources Information Center

    Levin, Sandy

    1989-01-01

    Presents learning activities and resources for teaching senior level criminal law courses. Topics covered include arrest, search and seizure, bail, trial procedures, sentencing, and prisons. Objective is to encourage students to address societal issues. (LS)

  20. Potential conservation laws

    SciTech Connect

    Kunzinger, Michael; Popovych, Roman O.

    2008-10-15

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

  1. Bullying Policies and Laws

    MedlinePlus

    ... Policies & Laws | Español Search Stopbullying.gov WHAT IS BULLYING Definition The Roles Kids Play Other Types of Aggressive Behavior CYBER BULLYING What is Cyberbullying? Prevent Cyberbullying Report Cyberbullying WHO ...

  2. Disobeying Immoral Laws.

    ERIC Educational Resources Information Center

    Israel, Elfie

    1994-01-01

    Describes how one teacher continued to teach after becoming pregnant, even though this was against school policy. Reminds teachers that Henry Thoreau claimed it is moral to disobey an immoral law. (HB)

  3. Optical monitoring for power law fluids during spin coating.

    PubMed

    Jardim, P L G; Michels, A F; Horowitz, F

    2012-01-30

    Optical monitoring is applied, in situ and in real time, to non-newtonian, power law fluids in the spin coating process. An analytical exact solution is presented for thickness evolution that well fits to most measurement data. As result, typical rheological parameters are obtained for several CMC (carboximetilcelullose) concentrations and rotation speeds. Optical monitoring thus precisely indicates applicability of the model to power law fluids under spin coating.

  4. Finite element implementation of a thermo-damage-viscoelastic constitutive model for hydroxyl-terminated polybutadiene composite propellant

    NASA Astrophysics Data System (ADS)

    Xu, Jinsheng; Han, Long; Zheng, Jian; Chen, Xiong; Zhou, Changsheng

    2017-02-01

    A thermo-damage-viscoelastic model for hydroxyl-terminated polybutadiene (HTPB) composite propellant with consideration for the effect of temperature was implemented in ABAQUS. The damage evolution law of the model has the same form as the crack growth equation for viscoelastic materials, and only a single damage variable S is considered. The HTPB propellant was considered as an isotropic material, and the deviatoric and volumetric strain-stress relations are decoupled and described by the bulk and shear relaxation moduli, respectively. The stress update equations were expressed by the principal stresses σ_{ii}R and the rotation tensor M, the Jacobian matrix in the global coordinate system J_{ijkl} was obtained according to the fourth-order tensor transformation rules. Two models having complex stress states were used to verify the accuracy of the constitutive model. The test results showed good agreement with the strain responses of characteristic points measured by a contactless optical deformation test system, which illustrates that the thermo-damage-viscoelastic model perform well at describing the mechanical properties of an HTPB propellant.

  5. Substitution of Azotobacter vinelandii hydrogenase small-subunit cysteines by serines can create insensitivity to inhibition by O2 and preferentially damages H2 oxidation over H2 evolution.

    PubMed Central

    McTavish, H; Sayavedra-Soto, L A; Arp, D J

    1995-01-01

    Mutants in which conserved cysteines 294, 297 or 64 and 65 of the Azotobacter vinelandii hydrogenase small subunit were replaced by serines were studied. Cysteines 294 and 297 are homologous to cysteines 246 and 249 of the Desulfovibrio gigas hydrogenase, and these cysteines are ligands to the [3Fe-4S] clusters (A. Volbeda, M.-H. Charon, C. Piras, E. C. Hatchikian, M. Frey, and J. C. Fontecilla-Camps, Nature (London) 373:580-587, 1995). Cysteine 65 is homologous to cysteine 20 of the D. gigas hydrogenase, and this cysteine is a ligand to the proximal [4Fe-4S] cluster. All three mutants retained some hydrogenase activity. All three mutants studied had H2 oxidation-to-H2 evolution activity ratios with whole cells of approximately 1.5, compared with 46 for the wild type. The changes preferentially deplete H2 oxidation activity, while having less effect on evolution. The K64,65C-->S hydrogenase was partially purified and had a specific activity for the evolution reaction that was 22% that of the wild type, while the oxidation-specific activity was 2% that of the wild type. Because cysteine 65 provides a ligand to the proximal [4Fe-4S] cluster, this cluster can be altered without entirely eliminating enzyme activity. Likewise, the detection of H2 evolution and H2 oxidation activities with whole cells and membranes of the K294C-->S and K297C-->S mutants indicates that the [3Fe-4S] cluster can also be altered or possibly eliminated without entirely eliminating enzyme activity. Membranes with K294C-->S or K297C-->S hydrogenase were uninhibited by O2 in H2 oxidation and uninhibited by H2 in H2 evolution. Wild-type membranes and membranes with K64,65C-->S hydrogenase were both sensitive to these inhibitors. These data indicate that the [3Fe-4S] cluster controls the reversible inhibition of hydrogenase activity by O2 or H2. PMID:7608067

  6. [When the violation of medical confidentiality is imposed by law: Another side effect of Law N° 20.584].

    PubMed

    Vega, Jorge; Quintana, María Soledad

    2016-02-01

    A law of rights and duties of patients was recently enacted in Chile (Law N° 20.584). When someone dies, the law allows his inheritors to have access to part or the totality of the medical record. Therefore, they may become acquainted of information that the patient gave in confidence to his physician, protected by "the medical confidentiality". The original bill included the possibility that a doctor could deny information that could cause harm to the former holder of the clinical record, but this precaution was banned by congressmen, seriously damaging the institution of "medical confidentiality", a cornerstone of the medical-patient relationship since the beginning of medicine.

  7. Teaching Law to the Public: Catalogue of Law School Projects.

    ERIC Educational Resources Information Center

    National Inst. for Citizen Education in the Law, Washington, DC.

    This catalog was developed to provide useful information about the many "Teaching Law to the Public" law school-based projects operating around the country in 1993-94. Aimed at law school project staff members, it is a handy reference to other law school programs. The catalog also is intended as a guide for everybody involved in…

  8. The law of the leading digits and the world religions

    NASA Astrophysics Data System (ADS)

    Mir, T. A.

    2012-02-01

    Benford's law states that the occurrence of significant digits in many data sets is not uniform but tends to follow a logarithmic distribution such that the smaller digits appear as first significant digits more frequently than the larger ones. We investigate here numerical data on the country-wise adherent distribution of seven major world religions i.e. Christianity, Islam, Buddhism, Hinduism, Sikhism, Judaism and Baha'ism to see if the proportion of the leading digits occurring in the distribution conforms to Benford's law. We find that the adherent data of all the religions, except Christianity, excellently does conform to Benford's law. Furthermore, unlike the adherent data on Christianity, the significant digit distribution of the three major Christian denominations i.e. Catholicism, Protestantism and Orthodoxy obeys the law. Thus in spite of their complexity general laws can be established for the evolution of religious groups.

  9. Group invariant solution for a pre-existing fracture driven by a power-law fluid in permeable rock

    NASA Astrophysics Data System (ADS)

    Fareo, A. G.; Mason, D. P.

    2016-06-01

    Group invariant analytical and numerical solutions for the evolution of a two-dimensional fracture with nonzero initial length in permeable rock and driven by an incompressible non-Newtonian fluid of power-law rheology are obtained. The effect of fluid leak-off on the evolution of the power-law fluid fracture is investigated.

  10. Water laws and concepts

    USGS Publications Warehouse

    Thomas, H.E.

    1970-01-01

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

  11. Topography evolution of 500 keV Ar(4+) ion beam irradiated InP(100) surfaces - formation of self-organized In-rich nano-dots and scaling laws.

    PubMed

    Sulania, Indra; Agarwal, Dinesh C; Kumar, Manish; Kumar, Sunil; Kumar, Pravin

    2016-07-27

    We report the formation of self-organized nano-dots on the surface of InP(100) upon irradiating it with a 500 keV Ar(4+) ion beam. The irradiation was carried out at an angle of 25° with respect to the normal at the surface with 5 different fluences ranging from 1.0 × 10(15) to 1.0 × 10(17) ions per cm(2). The morphology of the ion-irradiated surfaces was examined by atomic force microscopy (AFM) and the formation of the nano-dots on the irradiated surfaces was confirmed. The average size of the nano-dots varied from 44 ± 14 nm to 94 ± 26 nm with increasing ion fluence. As a function of the ion fluence, the variation in the average size of the nano-dots has a great correlation with the surface roughness, which changes drastically up to the ion fluence of 1.0 × 10(16) ions per cm(2) and attains almost a saturation level for further irradiation. The roughness and the growth exponent values deduced from the scaling laws suggest that the kinetic sputtering and the large surface diffusion steps of the atoms are the primary reasons for the formation of the self-organized nanodots on the surface. X-ray photo-electron spectroscopy (XPS) studies show that the surface stoichiometry changes with the ion fluence. With irradiation, the surface becomes more indium (In)-rich owing to the preferential sputtering of the phosphorus atoms (P) and the pure metallic In nano-dots evolve at the highest ion fluence. The cross-sectional scanning electron microscopy (SEM) analysis of the sample irradiated with the highest fluence showed the absence of the nanostructuring beneath the surface. The surface morphological changes at this medium energy ion irradiation are discussed in correlation with the low and high energy experiments to shed more light on the mechanism of the well separated nano-dot formation.

  12. Numerical methods for nonlinear hillslope transport laws

    NASA Astrophysics Data System (ADS)

    Perron, J. Taylor

    2011-06-01

    The numerical methods used to solve nonlinear sediment transport equations often set very restrictive limits on the stability and accuracy of landscape evolution models. This is especially true for hillslope transport laws in which sediment flux increases nonlinearly as the surface slope approaches a limiting value. Explicit-time finite difference methods applied to such laws are subject to fundamental limits on numerical stability that require time steps much shorter than the timescales over which landscapes evolve, creating a heavy computational burden. I present an implicit method for nonlinear hillslope transport that builds on a previously proposed approach to modeling alluvial sediment transport and improves stability and accuracy by avoiding the direct calculation of sediment flux. This method can be adapted to any transport law in which the expression for sediment flux is differentiable. Comparisons of numerical solutions with analytic solutions in one and two dimensions show that the implicit method retains the accuracy of a standard explicit method while permitting time steps several orders of magnitude longer than the maximum stable time step for the explicit method. The ability to take long time steps affords a substantial savings in overall computation time, despite the implicit method's higher per-iteration computational cost. Implicit models for hillslope evolution also offer a distinct advantage when modeling the response of hillslopes to incising channels.

  13. Nurturing Respect for the Law.

    ERIC Educational Resources Information Center

    Ioffe, M. G.

    1978-01-01

    Describes the content and methodology of elective courses which expand Soviet student's understanding of the Soviet state and the courts, the structure of power, and the basic rights and duties of the citizen. Courses in labor law, love and family law, criminal law, and constitutional law expand the current social studies curriculum. (KC)

  14. Physical Laws for Mechanobiology

    NASA Technical Reports Server (NTRS)

    Freed, Alan D.

    2007-01-01

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

  15. Effect of Cumulative Damage on Rocket Motor Service Life

    NASA Astrophysics Data System (ADS)

    Gligorijević, Nikola; Živković, Saša; Subotić, Sredoje; Rodić, Vesna; Gligorijević, Ivan

    2015-10-01

    Two series of antihail rocket propellant grains failed only 3 months after production, due to the appearance of cracks in the grain channel. Structural integrity analysis demonstrated sufficient reliability at the beginning of service life. Further analysis showed that under temperature loads, cumulative damage during the short period in field stocks caused the grain failure, despite the established opinion that such failure can become significant only after lengthy storage. A linear cumulative damage law is evaluated by exposing a number of hydroxyl-terminated polybutadiene (HTPB) composite propellant specimens to different but constant stress levels. The analysis showed that cumulative damage must not be overlooked at the design stage. Further, a positive correlation between the propellant cumulative damage law and tensile strength is strongly indicated.

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

    NASA Astrophysics Data System (ADS)

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

    2012-01-01

    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.

  17. Criminal Law Study Guide

    DTIC Science & Technology

    1991-08-01

    0507 ARTICLE 134’S LIMITATIONS 5-41 0508 ARTICLE 133’S LIMITATIONS 5-44 0 CHAPTER VI DRUG OFFENSES 0600 HISTORICAL OVERVIEW 6-1 0601 THEORIES OF...b) battery, (c) maiming, and (d) murder. 2. Defined and made punishable by law. Basic to the American theory of justice is the principle that there...necessary to be familiar with the common law background since the trial counsel must still adopt a particular theory to establish the accused’s

  18. Criminal Law Study Guide

    DTIC Science & Technology

    1989-03-01

    THEORIES OF PROSECUTION 6-1 0602 RELATIONSHIP AMONG DRUG OFFENSES 6-19 0603 REFERENCE TO OTHER AREAS 6-21 Aooession For NTIS GRA&I DTIC TAB 0 Unannounoed...punishable by law. Basic to the American theory of justice is the principle that there can be no punishment for harmful conduct unless it was...simplified, it is still necessary to be familiar with the common law background, since the trial counsel must still adopt a particular theory to establish the

  19. The trespasses of property law.

    PubMed

    Wall, Jesse

    2014-01-01

    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.

  20. Time-evolving statistics of cavitation damage on metallic surfaces.

    PubMed

    Diodati, P; Marchesoni, F

    2002-11-01

    The statistics of surface damage on polycrystalline aluminium plates caused by acoustic cavitation is studied experimentally as a function of time. Cavitation is shown to produce a uniform distribution of crater-like holes with different depth, area and eccentricity. Most notably, the size distribution of such craters evolves with time from a gamma function into a power law. By contrast, on the surface of a martensitic Cu-Ni-Al crystal cavitation damage generates ramified patterns, reminiscent of a fractal object.

  1. Diffusion Processes Satisfying a Conservation Law Constraint

    DOE PAGES

    Bakosi, J.; Ristorcelli, J. R.

    2014-03-04

    We investigate coupled stochastic differential equations governing N non-negative continuous random variables that satisfy a conservation principle. In various fields a conservation law requires that a set of fluctuating variables be non-negative and (if appropriately normalized) sum to one. As a result, any stochastic differential equation model to be realizable must not produce events outside of the allowed sample space. We develop a set of constraints on the drift and diffusion terms of such stochastic models to ensure that both the non-negativity and the unit-sum conservation law constraint are satisfied as the variables evolve in time. We investigate the consequencesmore » of the developed constraints on the Fokker-Planck equation, the associated system of stochastic differential equations, and the evolution equations of the first four moments of the probability density function. We show that random variables, satisfying a conservation law constraint, represented by stochastic diffusion processes, must have diffusion terms that are coupled and nonlinear. The set of constraints developed enables the development of statistical representations of fluctuating variables satisfying a conservation law. We exemplify the results with the bivariate beta process and the multivariate Wright-Fisher, Dirichlet, and Lochner’s generalized Dirichlet processes.« less

  2. Diffusion Processes Satisfying a Conservation Law Constraint

    SciTech Connect

    Bakosi, J.; Ristorcelli, J. R.

    2014-03-04

    We investigate coupled stochastic differential equations governing N non-negative continuous random variables that satisfy a conservation principle. In various fields a conservation law requires that a set of fluctuating variables be non-negative and (if appropriately normalized) sum to one. As a result, any stochastic differential equation model to be realizable must not produce events outside of the allowed sample space. We develop a set of constraints on the drift and diffusion terms of such stochastic models to ensure that both the non-negativity and the unit-sum conservation law constraint are satisfied as the variables evolve in time. We investigate the consequences of the developed constraints on the Fokker-Planck equation, the associated system of stochastic differential equations, and the evolution equations of the first four moments of the probability density function. We show that random variables, satisfying a conservation law constraint, represented by stochastic diffusion processes, must have diffusion terms that are coupled and nonlinear. The set of constraints developed enables the development of statistical representations of fluctuating variables satisfying a conservation law. We exemplify the results with the bivariate beta process and the multivariate Wright-Fisher, Dirichlet, and Lochner’s generalized Dirichlet processes.

  3. Law 20-30: Teacher Resource Manual.

    ERIC Educational Resources Information Center

    King, John; Jackson, Landis

    Law 20, in the Alberta (Canada) educational system, is an introductory course with three core modules: (1) "Nature of Law and Civil Law System," (2) "Contract Law," and (3) "Family Law." Law 30 consists of (1) "Basic Rights and Responsibilities," (2) "Labour Law," and (3) "Property Law."…

  4. The evolution of helicopters

    NASA Astrophysics Data System (ADS)

    Chen, R.; Wen, C. Y.; Lorente, S.; Bejan, A.

    2016-07-01

    Here, we show that during their half-century history, helicopters have been evolving into geometrically similar architectures with surprisingly sharp correlations between dimensions, performance, and body size. For example, proportionalities emerge between body size, engine size, and the fuel load. Furthermore, the engine efficiency increases with the engine size, and the propeller radius is roughly the same as the length scale of the whole body. These trends are in accord with the constructal law, which accounts for the engine efficiency trend and the proportionality between "motor" size and body size in animals and vehicles. These body-size effects are qualitatively the same as those uncovered earlier for the evolution of aircraft. The present study adds to this theoretical body of research the evolutionary design of all technologies [A. Bejan, The Physics of Life: The Evolution of Everything (St. Martin's Press, New York, 2016)].

  5. 43 CFR 11.17 - Compliance with applicable laws and standards.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Compliance with applicable laws and standards. 11.17 Section 11.17 Public Lands: Interior Office of the Secretary of the Interior NATURAL RESOURCE DAMAGE ASSESSMENTS Introduction § 11.17 Compliance with applicable laws and standards. (a)...

  6. 43 CFR 11.17 - Compliance with applicable laws and standards.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false Compliance with applicable laws and standards. 11.17 Section 11.17 Public Lands: Interior Office of the Secretary of the Interior NATURAL RESOURCE DAMAGE ASSESSMENTS Introduction § 11.17 Compliance with applicable laws and standards. (a)...

  7. Corrosion Damage Functions

    SciTech Connect

    Jones, Russell H.

    2002-11-30

    Corrosion damage can lead to reduced operational lifetimes. Often this damage is not as obvious as general corrosion but takes the form of pits, intergranular corrosion, crevice corrosion and hydrogen absorption. These types of corrosion damage lead to stress corrosion cracking, hydrogen induced cracking and corrosion fatigue. A critical step in defining a corrosion damage function is determining the relationship between the corrosion damage, the resulting crack propagation mechanism and component lifetimes. The sequence of events is often some localized corrosion event such as pitting, transition of the pit to a planar crack, propagation of this short crack, transition of the short crack to long crack conditions and continued propagation through Stage I, II, and III of the long crack SCC regimes. A description of critical corrosion damage processes and examples of the transition to long crack SCC conditions will be discussed.

  8. Damage Analysis of Rectangular Section Composite Beam under Pure Bending

    NASA Astrophysics Data System (ADS)

    Liu, Yiping; Xiao, Fan; Liu, Zejia; Tang, Liqun; Fang, Daining

    2013-02-01

    Laminated composite beams are commonly used in engineering applications involving macro to nano structures. Based on the assumption that plain sections remain plain after deformation, this paper analyzes stress distributions in cross-ply laminated composite beams with rectangular cross-sections, and formulates the basic damage equations through Kachanov's damage definition and Janson's failure criterion. The location of the neutral axis and the ultimate bending moment are obtained for pure bending cases. The effect of the elastic modulus of the two layers on the damage evolution is analyzed; a reasonable damage composite beam model is proposed to predict the ultimate bending moment.

  9. Computing beyond Moore's Law

    SciTech Connect

    Shalf, John M.; Leland, Robert

    2015-12-01

    Here, photolithography systems are on pace to reach atomic scale by the mid-2020s, necessitating alternatives to continue realizing faster, more predictable, and cheaper computing performance. If the end of Moore's law is real, a research agenda is needed to assess the viability of novel semiconductor technologies and navigate the ensuing challenges.

  10. Environment Law Review--1970.

    ERIC Educational Resources Information Center

    Sherrod, H. Floyd; And Others

    This is the first of several volumes to be published annually in the field of environmental law. It contains material from periodicals published in early 1970, 1969, and several articles of special significance which appeared in periodicals bearing 1968 dates. It has been collected primarily for lawyers so they may have, in convenient reference…

  11. Financial Disclosure Laws.

    ERIC Educational Resources Information Center

    Merz, Carol

    1983-01-01

    A study of school board presidents and superintendents in Washington, Missouri, and New Jersey reveals that strict financial disclosure laws tend to reduce the number of professionals on boards; however, board members with professional occupations differ from other board members on a number of measures. (MLF)

  12. Demonstrating Newton's Second Law.

    ERIC Educational Resources Information Center

    Fricker, H. S.

    1994-01-01

    Describes an apparatus for demonstrating the second law of motion. Provides sample data and discusses the merits of this method over traditional methods of supplying a constant force. The method produces empirical best-fit lines which convincingly demonstrate that for a fixed mass, acceleration is proportional to force. (DDR)

  13. Know Your Laws.

    ERIC Educational Resources Information Center

    Watson, Joan Q.

    These 24 self-contained competency-based modules are designed to acquaint Florida adult students with laws they 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 the Cognitive Domain and parallel the…

  14. The Gas Laws

    ERIC Educational Resources Information Center

    Raman, V. V.

    1973-01-01

    Inquires into the individual names and dates which are associated with the various perfect gas laws on the basis of published and historically researched works. Indicates the presence of eight features in giving a scientist credit for a scientific discovery. (CC)

  15. Law as Focus.

    ERIC Educational Resources Information Center

    Blythe, Joan Heiges

    1989-01-01

    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…

  16. Athletics and the Law.

    ERIC Educational Resources Information Center

    Appenzeller, Herb

    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,…

  17. Boyle's Law Experiment.

    ERIC Educational Resources Information Center

    Hermens, Richard A.

    1983-01-01

    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…

  18. A Boyle's Law Demonstrator.

    ERIC Educational Resources Information Center

    Sathe, Dileep V.

    1984-01-01

    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)

  19. Students and the Law.

    ERIC Educational Resources Information Center

    Gluckman, Ivan B.

    This publication consists of 29 articles that were published between April 1974 and June 1977 in the "Students and the Law" column of the National Association of Secondary School Principals' magazine, the "Student Advocate." In editing the articles, an attempt has been made to eliminate or update any suggestions or conclusions that may have been…

  20. School Law Update, 1985.

    ERIC Educational Resources Information Center

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

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

  1. School Law Issue.

    ERIC Educational Resources Information Center

    Update on Law-Related Education, 1994

    1994-01-01

    This law-related education teaching resource calls attention to civil rights in the school. Julius Menacker gives an overview of major national school legislation and the federal courts' roles in the constitutional areas of equal protection, freedom of expression, and due process. Aggie Alvez offers new perspectives on the constitutional,…

  2. Environmental Law II.

    ERIC Educational Resources Information Center

    Continuing Legal Education in Colorado, Inc., Denver.

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

  3. Constitutional Law--Elective.

    ERIC Educational Resources Information Center

    Gallagher, Joan; Wood, Robert J.

    The elective unit on Constitutional Law is intended for 11th and 12th grade students. The unit is designed around major course goals which are to develop those concepts whereby students recognize and understand the following three topic areas: 1) Role of the Federal Judicial Branch of Government, 2) Supreme Court Cases Involving the Three Branches…

  4. ADHD and School Law.

    ERIC Educational Resources Information Center

    Gregg, Soleil

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

  5. Law in Outer Space.

    ERIC Educational Resources Information Center

    Schmidt, William G.

    1997-01-01

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

  6. Team Teaching School Law

    ERIC Educational Resources Information Center

    Vanko, John G.; Rogina, Raymond P.

    2005-01-01

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

  7. Desegregation Law; An Introduction.

    ERIC Educational Resources Information Center

    Integrated Education Associates, Evanston, IL.

    This booklet is comprised of the following: (i) School desegregation law: recent developments (by J. Harold Flannery), dealing with several threshold questions such as: What is illegal school segregation? What must be done about it and by whom? What will be the role of the courts after desegregation? (ii) School desegregation--the past five years,…

  8. Special Education Law Update.

    ERIC Educational Resources Information Center

    Zirkel, Perry A.

    1989-01-01

    Due to an error made in printing Professor Zirkel's "Special Education Law; Recent Developments" in Volume 48 (October 13, 1988), these updates to the article are printed. Citations are organized under the following major sections: (1) diagnosis and placement; (2) treatment issues; (3) financial issues; and (4) gifted students. (MLF)

  9. The Hungarian Library Law.

    ERIC Educational Resources Information Center

    1976

    This booklet includes the Law-Decree No. 15 on Libraries issued by the Presidium of the Hungarian People's Republic in 1976 and the decree of the Council of Ministers on its implementation. The purpose of the decree is to further the fulfilment of citizens' cultural demands, and meet the needs for special literature of both citizens and corporate…

  10. Lectures on Law Enforcement.

    ERIC Educational Resources Information Center

    Nettleship, Lois

    Three lectures on law enforcement are presented that were prepared for study purposes at Johnson County Community College. The first lecture examines the fundamental ideas of the Age of Enlightenment and discusses their influence on the American Revolution, the United States Constitution, and the Bill of Rights. Major provisions of the Bill of…

  11. Preventive Law Curriculum Guide.

    ERIC Educational Resources Information Center

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

    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…

  12. Equal Justice Under Law.

    ERIC Educational Resources Information Center

    Johnson, Earl, Jr., Ed.

    1994-01-01

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

  13. [Cloning and law in Hungary].

    PubMed

    Julesz, Máté

    2015-03-01

    Reproductive human cloning is prohibited in Hungary, as in many other countries. Therapeutic human cloning is not prohibited, just like in many other countries. Stem cell therapy is also allowed. Article III, paragraph (3) of the Hungarian basic law (constitution) strictly forbids total human cloning. Article 1 of the Additional Protocol to the Oviedo Convention, on the Prohibition of Cloning Human Beings (1998) stipulates that any intervention seeking to create a human being genetically identical to another human being, whether living or dead, is prohibited. In Hungary, according to Article 174 of the Criminal Code, total human cloning constitutes a crime. Article 180, paragraph (3) of the Hungarian Act on Health declares that embryos shall not be brought about for research purposes; research shall be conducted only on embryos brought about for reproductive purposes when this is authorized by the persons entitled to decide upon its disposal, or when the embryo is damaged. Article 180, paragraph (5) of the Hungarian Act on Health stipulates that multiple individuals who genetically conform to one another shall not be brought about. According to Article 181, paragraph (1) of the Hungarian Act on Health, an embryo used for research shall be kept alive for not longer than 14 days, not counting the time it was frozen for storage and the time period of research.

  14. Impact damage of composites

    NASA Technical Reports Server (NTRS)

    Wu, Hsi-Young T.; Springer, George S.

    1986-01-01

    A model is described for estimating the impact damage of fiber reinforced composite plates. The displacements and stresses are calculated by a three dimensional transient, finite element method of solution of the governing equations applicable to a linearly elastic body. The region in which damage occurs is estimated using the Tsai-Wu failure criterion. A computer code was developed which can be used to calculate the impact force, displacements and velocities of the plate and the impact body, stresses and strains in the plate, and the damage area. Sample numerical results are presented illustrating the type of information provided by the code. Comparisons between measured and calculated damage areas are also given.

  15. Damage Tolerance of Composites

    NASA Technical Reports Server (NTRS)

    Hodge, Andy

    2007-01-01

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

  16. Archie's law - a reappraisal

    NASA Astrophysics Data System (ADS)

    Glover, Paul W. J.

    2016-07-01

    When scientists apply Archie's first law they often include an extra parameter a, which was introduced about 10 years after the equation's first publication by Winsauer et al. (1952), and which is sometimes called the "tortuosity" or "lithology" parameter. This parameter is not, however, theoretically justified. Paradoxically, the Winsauer et al. (1952) form of Archie's law often performs better than the original, more theoretically correct version. The difference in the cementation exponent calculated from these two forms of Archie's law is important, and can lead to a misestimation of reserves by at least 20 % for typical reservoir parameter values. We have examined the apparent paradox, and conclude that while the theoretical form of the law is correct, the data that we have been analysing with Archie's law have been in error. There are at least three types of systematic error that are present in most measurements: (i) a porosity error, (ii) a pore fluid salinity error, and (iii) a temperature error. Each of these systematic errors is sufficient to ensure that a non-unity value of the parameter a is required in order to fit the electrical data well. Fortunately, the inclusion of this parameter in the fit has compensated for the presence of the systematic errors in the electrical and porosity data, leading to a value of cementation exponent that is correct. The exceptions are those cementation exponents that have been calculated for individual core plugs. We make a number of recommendations for reducing the systematic errors that contribute to the problem and suggest that the value of the parameter a may now be used as an indication of data quality.

  17. Evaluating glaucoma damage: emerging imaging technologies

    PubMed Central

    Kostanyan, Tigran; Wollstein, Gadi; Schuman, Joel S

    2015-01-01

    The use of ocular imaging tools to estimate structural and functional damage in glaucoma has become a common clinical practice and a substantial focus of vision research. The evolution of the imaging technologies through increased scanning speed, penetration depth, image registration and development of multimodal devices has the potential to detect the pathology more reliably and in earlier stages. This review is focused on new ocular imaging modalities used for glaucoma diagnosis. PMID:27087829

  18. The evolution of complex life.

    PubMed

    Billingham, J

    1989-01-01

    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.

  19. Hubble's Law Implies Benford's Law for Distances to Galaxies

    NASA Astrophysics Data System (ADS)

    Hill, Theodore P.; Fox, Ronald F.

    2016-03-01

    A recent article by Alexopoulos and Leontsinis presented empirical evidence that the first digits of the distances from the Earth to galaxies are a reasonably good fit to the probabilities predicted by Benford's law, the well known logarithmic statistical distribution of significant digits. The purpose of the present article is to give a theoretical explanation, based on Hubble's law and mathematical properties of Benford's law, why galaxy distances might be expected to follow Benford's law. The new galaxy-distance law derived here, which is robust with respect to change of scale and base, to additive and multiplicative computational or observational errors, and to variability of the Hubble constant in both time and space, predicts that conformity to Benford's law will improve as more data on distances to galaxies becomes available. Conversely, with the logical derivation of this law presented here, the recent empirical observations may be viewed as independent evidence of the validity of Hubble's law.

  20. A Quantitative Examination Whether Education Mitigates Stress Levels among Law Enforcement Officers

    ERIC Educational Resources Information Center

    Metts, Gary A.

    2012-01-01

    Stress is damaging if it is continual, overwhelming. and prolonged. Law enforcement officers face stressful events daily. A relationship exists between stress levels and the physical and psychological effects to the human body. Although there is a general understanding of the damage stress can do physically and psychologically, many elements that…

  1. Predicting bulk damage in NIF triple harmonic generators

    SciTech Connect

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

    1998-09-18

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

  2. Damage and intensity survey

    USGS Publications Warehouse

    Reagor, G.; Brewer, L.R.

    1992-01-01

    A field team (the tuhors) from the National Earthquake Information Center (USGS) conducted a damage survey of the epicentral area in the week following the earthquakes. Detailed information about damage and where and how strongly the earthquakes were felt was obtained through interviews with local residents and personal observations. 

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

    SciTech Connect

    Bhattcharya, B.; Ellingwood, B.

    1998-02-01

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

  4. Fatigue damage prognosis using affine arithmetic

    NASA Astrophysics Data System (ADS)

    Gbaguidi, Audrey; Kim, Daewon

    2014-02-01

    Among the essential steps to be taken in structural health monitoring systems, damage prognosis would be the field that is least investigated due to the complexity of the uncertainties. This paper presents the possibility of using Affine Arithmetic for uncertainty propagation of crack damage in damage prognosis. The structures examined are thin rectangular plates made of titanium alloys with central mode I cracks and a composite plate with an internal delamination caused by mixed mode I and II fracture modes, under a harmonic uniaxial loading condition. The model-based method for crack growth rates are considered using the Paris Erdogan law model for the isotropic plates and the delamination growth law model proposed by Kardomateas for the composite plate. The parameters for both models are randomly taken and their uncertainties are considered as defined by an interval instead of a probability distribution. A Monte Carlo method is also applied to check whether Affine Arithmetic (AA) leads to tight bounds on the lifetime of the structure.

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

    ERIC Educational Resources Information Center

    Haimbaugh, George D., Jr.

    1981-01-01

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

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

    ERIC Educational Resources Information Center

    Suagee, Dean B.

    2003-01-01

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

  7. Eye for an Eye, A Survey History of Law, Social Studies: 6448.06.

    ERIC Educational Resources Information Center

    Henderson, Jerry W.

    This guide is one of a series in the Quinmester Program to aid high school teachers in planning instructional programs concerning the origins and evolution of our system of law. The purpose of this course of study is to help students understand the rights and responsibilities of citizens under the law; to motivate them to make judgments upon the…

  8. Empirical tests of Zipf's law mechanism in open source Linux distribution.

    PubMed

    Maillart, T; Sornette, D; Spaeth, S; von Krogh, G

    2008-11-21

    Zipf's power law is a ubiquitous empirical regularity found in many systems, thought to result from proportional growth. Here, we establish empirically the usually assumed ingredients of stochastic growth models that have been previously conjectured to be at the origin of Zipf's law. We use exceptionally detailed data on the evolution of open source software projects in Linux distributions, which offer a remarkable example of a growing complex self-organizing adaptive system, exhibiting Zipf's law over four full decades.

  9. Bayes and the Law

    PubMed Central

    Fenton, Norman; Neil, Martin; Berger, Daniel

    2016-01-01

    Although the last forty years has seen considerable growth in the use of statistics in legal proceedings, it is primarily classical statistical methods rather than Bayesian methods that have been used. Yet the Bayesian approach avoids many of the problems of classical statistics and is also well suited to a broader range of problems. This paper reviews the potential and actual use of Bayes in the law and explains the main reasons for its lack of impact on legal practice. These include misconceptions by the legal community about Bayes’ theorem, over-reliance on the use of the likelihood ratio and the lack of adoption of modern computational methods. We argue that Bayesian Networks (BNs), which automatically produce the necessary Bayesian calculations, provide an opportunity to address most concerns about using Bayes in the law. PMID:27398389

  10. Modernizing public health law.

    PubMed

    Griffith, Richard; Tengnah, Cassam

    2011-07-01

    The rapid spread of a mutant strain of Escherichia coli throughout Europe highlights the need for modern and flexible public health laws to identify, control and treat infections and contamination that give significant concern for the health of the population. In this article, Richard Griffith and Cassam Tengnah outline the amendments to the Public Health (Control of Disease) Act 1984 that adopt an all-hazards approach to threats to public health.

  11. Upstream health law.

    PubMed

    Sage, William M; McIlhattan, Kelley

    2014-01-01

    For the first time, entrepreneurs are aggressively developing new technologies and business models designed to improve individual and population health, not just to deliver specialized medical care. Consumers of these goods and services are not yet "patients"; they are simply people. As this sector of the health care industry expands, it is likely to require new forms of legal governance, which we term "upstream health law."

  12. Ethics and Law

    NASA Astrophysics Data System (ADS)

    Vilacoba Ramos, Andrés

    2007-04-01

    Ethics are the set of moral rules that govern human conduct. Hegel, for his part, asserted that ethicity implied the full realization of freedom, as well as the suppression of it as arbitrariness. In this paper, we point out that, through the relation between Law and Ethics, we can discover how high are the Ethics of a society, as well as the adherence of its members to it.

  13. Compensation law in composites

    NASA Astrophysics Data System (ADS)

    Dufresne, A.; Lavergne, C.; Lacabanne, C.

    1993-12-01

    The experimental resolution of the α retardation / relaxation mode of model composites epoxy resin- glass beads has been performed using Thermo Stimulated Creep (TSCr) and Thermo Stimulated Currents (TSC) spectroscopies. The distributed retardation / relaxation times τ are found to obey a compensation law, which is characteristic of cooperative movements liberated at the vicinity of T g. The T c and τ c compensation parameters reveal that the microstructure is strongly linked to the nature of the interface.

  14. Thermodynamics and evolution.

    PubMed

    Demetrius, L

    2000-09-07

    The science of thermodynamics is concerned with understanding the properties of inanimate matter in so far as they are determined by changes in temperature. The Second Law asserts that in irreversible processes there is a uni-directional increase in thermodynamic entropy, a measure of the degree of uncertainty in the thermal energy state of a randomly chosen particle in the aggregate. The science of evolution is concerned with understanding the properties of populations of living matter in so far as they are regulated by changes in generation time. Directionality theory, a mathematical model of the evolutionary process, establishes that in populations subject to bounded growth constraints, there is a uni-directional increase in evolutionary entropy, a measure of the degree of uncertainty in the age of the immediate ancestor of a randomly chosen newborn. This article reviews the mathematical basis of directionality theory and analyses the relation between directionality theory and statistical thermodynamics. We exploit an analytic relation between temperature, and generation time, to show that the directionality principle for evolutionary entropy is a non-equilibrium extension of the principle of a uni-directional increase of thermodynamic entropy. The analytic relation between these directionality principles is consistent with the hypothesis of the equivalence of fundamental laws as one moves up the hierarchy, from a molecular ensemble where the thermodynamic laws apply, to a population of replicating entities (molecules, cells, higher organisms), where evolutionary principles prevail.

  15. Turning around Newton's Second Law

    ERIC Educational Resources Information Center

    Goff, John Eric

    2004-01-01

    Conceptual and quantitative difficulties surrounding Newton's second law often arise among introductory physics students. Simply turning around how one expresses Newton's second law may assist students in their understanding of a deceptively simple-looking equation.

  16. Henry's Law and Noisy Knuckles.

    ERIC Educational Resources Information Center

    Kimbrough, Doris R.

    1999-01-01

    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)

  17. 77 FR 19799 - Pipeline Safety: Pipeline Damage Prevention Programs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-02

    ...This Notice of Proposed Rulemaking (NPRM) seeks to revise the Pipeline Safety Regulations to: Establish criteria and procedures for determining the adequacy of state pipeline excavation damage prevention law enforcement programs; establish an administrative process for making adequacy determinations; establish the Federal requirements PHMSA will enforce in states with inadequate excavation......

  18. 48 CFR 622.302 - Liquidated damages and overtime pay.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Liquidated damages and overtime pay. 622.302 Section 622.302 Federal Acquisition Regulations System DEPARTMENT OF STATE SOCIOECONOMIC PROGRAMS APPLICATION OF LABOR LAWS TO GOVERNMENT ACQUISITIONS Contract Work Hours and...

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

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Liquidated damages and overtime pay. 1422.302 Section 1422.302 Federal Acquisition Regulations System DEPARTMENT OF THE INTERIOR SOCIOECONOMIC PROGRAMS APPLICATION OF LABOR LAWS TO GOVERNMENT ACQUISITIONS Contract Work Hours and...

  20. Enforcing pollution control laws

    SciTech Connect

    Russell, C.S.; Harrington, W.; Vaughan, W.J.

    1986-01-01

    The heightened environmental consciousness of the 1970s prompted passage of a multitude of ambitious and unprecedented laws designed to clean up the environment and protect it for future generations. But beyond the mere passing of laws lay the difficult tasks of implementing, monitoring, and enforcing them. The authors of this book describe the current state of air and water pollution monitoring and enforcement activity a decade later, within the context of relevant legal, technological, and statistical developments. They mediate between the concerns of the theoretical literature-where it is generally assumed that violations are discovered and punished-and the real world-where violations are rarely discovered and almost never punished. Monitoring and enforcement procedures to date have been aimed at achieving initial rather than continuing compliance with regulations. The authors contend that it is time for a new approach focusing on the enduring problems of compliance. Economic models are used to show the extent of the difficulties involved in monitoring and enforcing pollution control laws on a continuous basis.

  1. Sexuality and the law.

    PubMed

    Portelli, C J

    1998-01-01

    Federal, state, and local laws in the US now govern almost every aspect of sexuality. This includes sexuality at the workplace, sexuality education, adolescent sexuality, access to sexuality information and sexually explicit materials, sexual orientation, and sexually transmitted disease(STD)/HIV transmission. Almost 33% of the US Supreme Court's docket this past term concerned sexuality issues. In contrast to 50 years ago, when sexuality law was confined to the criminal arena, contemporary "sex crimes" primarily relate to nonconsensual and exploitative behaviors. It is time for lawmakers, judges, lawyers, policy analysts, lobbyists, and advocates to realize they cannot legislate or litigate how, when, or why people fall in love. Rather, the role of the law should be to create and preserve models of justice and equality that seek to preserve one's individual rights to privacy and freedom to choose in matters related to one's sexuality. This includes free access to age-appropriate sexuality information, the right to marriage and children regardless of sexual orientation, comprehensive sexuality education that encompasses information about avoiding unwanted pregnancies and HIV/STDs, access to contraception and abortion, protection from sexually abusive or exploitative relationships, and access to sexual health care.

  2. FTS evolution

    NASA Technical Reports Server (NTRS)

    Provost, David E.

    1990-01-01

    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.

  3. Teaching Evolution

    ERIC Educational Resources Information Center

    Bryner, Jeanna

    2005-01-01

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

  4. Life and evolution as physics

    PubMed Central

    Bejan, Adrian

    2016-01-01

    ABSTRACT What is evolution and why does it exist in the biological, geophysical and technological realms — in short, everywhere? Why is there a time direction — a time arrow — in the changes we know are happening every moment and everywhere? Why is the present different than the past? These are questions of physics, about everything, not just biology. The answer is that nothing lives, flows and moves unless it is driven by power. Physics sheds light on the natural engines that produce the power destroyed by the flows, and on the free morphing that leads to flow architectures naturally and universally. There is a unifying tendency across all domains to evolve into flow configurations that provide greater access for movement. This tendency is expressed as the constructal law of evolutionary flow organization everywhere. Here I illustrate how this law of physics accounts for and unites the life and evolution phenomena throughout nature, animate and inanimate. PMID:27489579

  5. Constitutive modeling of viscoplastic damage in solder material

    SciTech Connect

    WEI,YONG; CHOW,C.L.; NEILSEN,MICHAEL K.; FANG,HUEI ELIOT

    2000-04-17

    This paper presents a constitutive modeling of viscoplastic damage in 63Sn-37Pb solder material taking into account the effects of microstructural change in grain coarsening. Based on the theory of damage mechanics, a two-scalar damage model is developed by introducing the damage variables and the free energy equivalence principle. An inelastic potential function based on the concept of inelastic damage energy release rate is proposed and used to derive an inelastic damage evolution equation. The validation of the model is carried out for the viscoplastic material by predicting monotonic tensile behavior and tensile creep curves at different temperatures. The softening behavior of the material under monotonic tension loading can be characterized with the model. The results demonstrate adequately the validity of the proposed viscoplastic constitutive modeling for the solder material.

  6. Army Medicine and the Law

    DTIC Science & Technology

    1964-01-01

    D. Blood Alcohol Tests and Drunken Drivers E. Hypnosis in the Law F. Lie-Detectors Can Lie! G, Forensic Pathology and the Law H. The Medicolegal...The Federal Tort Claims Act, copyright, 1963. b. Consent to Medical Procedures, copyright 1963. c. Hypnosis in the Law, copyright 1964. d. Blood...Tort Claims Act, copyright 1963. b. Forensic Pathology and the Law, copyright 1964. c. Some Legal Aspects of Military Preventive Medicine, copyright

  7. Reordering American Constitutional Law Teaching.

    ERIC Educational Resources Information Center

    Gerber, Scott D.

    1994-01-01

    Maintains that constitutional law is the cornerstone of an undergraduate public law curriculum. Asserts that there is a welcome trend toward teaching the subject over a two-semester sequence, instead of only one. Describes course content and teaching strategies used in a college constitutional law course. (CFR)

  8. Freedom under Law. Revised edition.

    ERIC Educational Resources Information Center

    Denver Public Schools, CO.

    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…

  9. Higher Education and the Law.

    ERIC Educational Resources Information Center

    Edwards, Harry T.; Nordin, Virginia Davis

    The proliferation of laws, regulations, and judicial opinions affecting higher education and the nature of the impact of these laws on the academic community are examined. Designed for use by both students and practitioners, the book employs the "case method" design based on the belief that law cases furnish the best sources for study…

  10. Law-Focused Education: Iowa.

    ERIC Educational Resources Information Center

    University of Northern Iowa, Cedar Falls. Malcolm Price Lab. School.

    This law-focused resource booklet is intended to help secondary level students learn about the civil law portion of Iowa's judicial system. The materials are designed to help students understand how to deal with conflict in a peaceful and orderly manner and how to cope with decision making in personal law situations as related to the family, the…

  11. Law and family planning.

    PubMed

    Kirby, M D

    1984-03-17

    This discussion of law and family planning reviews some recent reports of the Australain Law Reform Commission (ALRC), the law as it affects family planning and the sexuality of young people with reference to the Irish dilemma, the law's approach in Ingland, Canada, and the US. The ALRC works only on references recived by it from the Federal Attorney General. No reference so far received has been specific to the issues of family planning, but some past and present projects are partly relevant. The most recent report of the ALRC, tabled in Federal Parliament in December 1983 related to privacy protection. An issue that arose in this inquiry related to the subject of the rights to privacy of young people. In a discussion paper the ALRC had suggestd that young persons between the ages of 12-16 should have certain defined legal protection of privacy, even against their parents. Specifically, the ALRC was thinking of medical advice and school counseling. Obviously the issue of contraceptive advice was raised in this context, and never has a tenative proposal of the ALRC engendered so much bitter criticism. The Commission modified its proposal on this topic and the details of the revised proposals are disclosed in its report. Clearly, the rights of young people in regard to sexual advice, education, and treatment are matters of great controversy and strongly divided community opinion. In Australia there are some who are totally opposed to family planning for themselves, their children, and even for others. Such opposition exists in the medical profession. Presumably, such people base their views on strongly held moral principles. They generally believe that contraception interferes in the ways of nature. Far from being promoted by open discussion and instruction in the schools, such matters are intimate concerns of a small circle, principally the family. In dealing with those aspects that concern the rights of parents in thes matters, attention turns to England's Gillick

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

    SciTech Connect

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

    2010-12-22

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

  13. War Damage Assessment

    NASA Technical Reports Server (NTRS)

    1994-01-01

    During and after the Persian Gulf war, hundreds of "oil lakes" were created in Kuwait by oil released from damaged wells. The lakes are a hazard to the Kuwait atmosphere, soil and ground water and must be carefully monitored. Boston University Center for Remote Sensing, assisted by other organizations, has accurately mapped the lakes using Landsat and Spot imagery. The war damage included the formation of over 300 oil lakes, oil pollution and sand dune movement. Total damage area is over 5,400 square kilometers - 30 percent of Kuwait's total surface area.

  14. Kinetics of wealth and the Pareto law

    NASA Astrophysics Data System (ADS)

    Boghosian, Bruce M.

    2014-04-01

    An important class of economic models involve agents whose wealth changes due to transactions with other agents. Several authors have pointed out an analogy with kinetic theory, which describes molecules whose momentum and energy change due to interactions with other molecules. We pursue this analogy and derive a Boltzmann equation for the time evolution of the wealth distribution of a population of agents for the so-called Yard-Sale Model of wealth exchange. We examine the solutions to this equation by a combination of analytical and numerical methods and investigate its long-time limit. We study an important limit of this equation for small transaction sizes and derive a partial integrodifferential equation governing the evolution of the wealth distribution in a closed economy. We then describe how this model can be extended to include features such as inflation, production, and taxation. In particular, we show that the model with taxation exhibits the basic features of the Pareto law, namely, a lower cutoff to the wealth density at small values of wealth, and approximate power-law behavior at large values of wealth.

  15. Kinetics of wealth and the Pareto law.

    PubMed

    Boghosian, Bruce M

    2014-04-01

    An important class of economic models involve agents whose wealth changes due to transactions with other agents. Several authors have pointed out an analogy with kinetic theory, which describes molecules whose momentum and energy change due to interactions with other molecules. We pursue this analogy and derive a Boltzmann equation for the time evolution of the wealth distribution of a population of agents for the so-called Yard-Sale Model of wealth exchange. We examine the solutions to this equation by a combination of analytical and numerical methods and investigate its long-time limit. We study an important limit of this equation for small transaction sizes and derive a partial integrodifferential equation governing the evolution of the wealth distribution in a closed economy. We then describe how this model can be extended to include features such as inflation, production, and taxation. In particular, we show that the model with taxation exhibits the basic features of the Pareto law, namely, a lower cutoff to the wealth density at small values of wealth, and approximate power-law behavior at large values of wealth.

  16. Dynamics and Adaptive Control for Stability Recovery of Damaged Aircraft

    NASA Technical Reports Server (NTRS)

    Nguyen, Nhan; Krishnakumar, Kalmanje; Kaneshige, John; Nespeca, Pascal

    2006-01-01

    This paper presents a recent study of a damaged generic transport model as part of a NASA research project to investigate adaptive control methods for stability recovery of damaged aircraft operating in off-nominal flight conditions under damage and or failures. Aerodynamic modeling of damage effects is performed using an aerodynamic code to assess changes in the stability and control derivatives of a generic transport aircraft. Certain types of damage such as damage to one of the wings or horizontal stabilizers can cause the aircraft to become asymmetric, thus resulting in a coupling between the longitudinal and lateral motions. Flight dynamics for a general asymmetric aircraft is derived to account for changes in the center of gravity that can compromise the stability of the damaged aircraft. An iterative trim analysis for the translational motion is developed to refine the trim procedure by accounting for the effects of the control surface deflection. A hybrid direct-indirect neural network, adaptive flight control is proposed as an adaptive law for stabilizing the rotational motion of the damaged aircraft. The indirect adaptation is designed to estimate the plant dynamics of the damaged aircraft in conjunction with the direct adaptation that computes the control augmentation. Two approaches are presented 1) an adaptive law derived from the Lyapunov stability theory to ensure that the signals are bounded, and 2) a recursive least-square method for parameter identification. A hardware-in-the-loop simulation is conducted and demonstrates the effectiveness of the direct neural network adaptive flight control in the stability recovery of the damaged aircraft. A preliminary simulation of the hybrid adaptive flight control has been performed and initial data have shown the effectiveness of the proposed hybrid approach. Future work will include further investigations and high-fidelity simulations of the proposed hybrid adaptive Bight control approach.

  17. Military Personnel Law Deskbook

    DTIC Science & Technology

    2006-08-01

    not a “taking” for which damages accrue. Ainsworth v. Barn Ballroom Co., 157 F.2d 97 (4th Cir. 1946). Standard of review is whether the action was...MCO 1700.27A, paras. 1402, 1405. A. Lotterie B. Pull-tab C. Sale of t bo D. Topless or nude dancing . AR 215-1, para. 8-13. E. Awarding alcohol as

  18. Thresholded Power law Size Distributions of Instabilities in Astrophysics

    NASA Astrophysics Data System (ADS)

    Aschwanden, Markus J.

    2015-11-01

    Power-law-like size distributions are ubiquitous in astrophysical instabilities. There are at least four natural effects that cause deviations from ideal power law size distributions, which we model here in a generalized way: (1) a physical threshold of an instability; (2) incomplete sampling of the smallest events below a threshold x0; (3) contamination by an event-unrelated background xb; and (4) truncation effects at the largest events due to a finite system size. These effects can be modeled in the simplest terms with a “thresholded power law” distribution function (also called generalized Pareto [type II] or Lomax distribution), N(x){dx}\\propto {(x+{x}0)}-a{dx}, where x0 > 0 is positive for a threshold effect, while x0 < 0 is negative for background contamination. We analytically derive the functional shape of this thresholded power law distribution function from an exponential growth evolution model, which produces avalanches only when a disturbance exceeds a critical threshold x0. We apply the thresholded power law distribution function to terrestrial, solar (HXRBS, BATSE, RHESSI), and stellar flare (Kepler) data sets. We find that the thresholded power law model provides an adequate fit to most of the observed data. Major advantages of this model are the automated choice of the power law fitting range, diagnostics of background contamination, physical instability thresholds, instrumental detection thresholds, and finite system size limits. When testing self-organized criticality models that predict ideal power laws, we suggest including these natural truncation effects.

  19. Scale-free networks are not robust under neutral evolution

    NASA Astrophysics Data System (ADS)

    Hörnquist, M.

    2001-11-01

    Recently, it has been shown that a large variety of different networks have power law (scale-free) distributions of connectivities. We investigate the robustness of such a distribution in discrete threshold networks under neutral evolution. The guiding principle for this is robustness in the resulting phenotype. The numerical results show that a power law distribution is not stable under such an evolution, and the network approaches a homogeneous form where the overall distribution of connectivities is given by a Poisson distribution.

  20. Nonlinear damage analysis: Postulate and evaluation

    NASA Technical Reports Server (NTRS)

    Leis, B. N.; Forte, T. P.

    1983-01-01

    The objective of this program is to assess the viability of a damage postulate which asserts that the fatigue resistance curve of a metal is history dependent due to inelastic action. The study focusses on OFE copper because this simple model material accentuates the inelastic action central to the damage postulate. Data relevant to damage evolution and crack initiation are developed via a study of surface topography. The effects of surface layer residual stresses are explored via comparative testing as were the effects in initial prestraining. The results of the study very clearly show the deformation history dependence of the fatigue resistance of OFE copper. Furthermore the concept of deformation history dependence is shown to qualitatively explain the fatigue resistance of all histories considered. Likewise quantitative predictions for block cycle histories are found to accurately track the observed results. In this respect the assertion that damage per cycle for a given level of the damage parameter is deformation history dependent appears to be physically justified.

  1. Discussion on ``Frontiers of the Second Law''

    NASA Astrophysics Data System (ADS)

    Lloyd, Seth; Bejan, Adrian; Bennett, Charles; Beretta, Gian Paolo; Butler, Howard; Gordon, Lyndsay; Grmela, Miroslav; Gyftopoulos, Elias P.; Hatsopoulos, George N.; Jou, David; Kjelstrup, Signe; Lior, Noam; Miller, Sam; Rubi, Miguel; Schneider, Eric D.; Sekulic, Dusan P.; Zhang, Zhuomin

    2008-08-01

    This article reports an open discussion that took place during the Keenan Symposium "Meeting the Entropy Challenge" (held in Cambridge, Massachusetts, on October 4, 2007) following the short presentations—each reported as a separate article in the present volume—by Adrian Bejan, Bjarne Andresen, Miguel Rubi, Signe Kjelstrup, David Jou, Miroslav Grmela, Lyndsay Gordon, and Eric Schneider. All panelists and the audience were asked to address the following questions • Is the second law relevant when we trap single ions, prepare, manipulate and measure single photons, excite single atoms, induce spin echoes, measure quantum entanglement? Is it possible or impossible to build Maxwell demons that beat the second law by exploiting fluctuations? • Is the maximum entropy generation principle capable of unifying nonequilibrium molecular dynamics, chemical kinetics, nonlocal and nonequilibrium rheology, biological systems, natural structures, and cosmological evolution? • Research in quantum computation and quantum information has raised many fundamental questions about the foundations of quantum theory. Are any of these questions related to the second law?

  2. Numerical Methods for Nonlinear Hillslope Transport Laws

    NASA Astrophysics Data System (ADS)

    Perron, J. T.

    2008-12-01

    The numerical methods used to solve nonlinear sediment transport equations often set restrictive limits on the stability and accuracy of landscape evolution models. This is especially true for hillslope transport laws in which sediment flux increases nonlinearly as the surface slope approaches a limiting value. Standard explicit finite difference methods applied to such laws are subject to fundamental limits on numerical stability that require time steps much shorter than the timescales over which landscapes evolve, creating a heavy computational burden. Methods that rely on cell-to-cell sediment routing schemes can introduce significant errors that may not be obvious unless the numerical solution is compared with a known solution. I present a new, implicit method for nonlinear hillslope transport that builds on a previously proposed approach to modeling alluvial sediment transport but avoids the use of a cell-to-cell sediment routing scheme. Comparisons of numerical solutions with analytic solutions in one and two dimensions show that the new method retains the accuracy of the explicit method while allowing timesteps several orders of magnitude longer than the maximum timesteps permitted by the explicit method. The method can be adapted to any transport law in which the expression for sediment flux is differentiable, including coupled systems in which sediment flux is a function of quantities such as soil depth.

  3. Stellar evolution.

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

  4. Court Disallows Damage Claims

    ERIC Educational Resources Information Center

    Tomson, Bernard; Coplan, Norman

    1976-01-01

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

  5. Composites Damage Tolerance Workshop

    NASA Technical Reports Server (NTRS)

    Gregg, Wayne

    2006-01-01

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

  6. LSD and Genetic Damage

    ERIC Educational Resources Information Center

    Dishotsky, Norman I.; And Others

    1971-01-01

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

  7. Nerve Damage (Diabetic Neuropathies)

    MedlinePlus

    ... may include numbness or insensitivity to pain or temperature a tingling, burning, or prickling sensation sharp pains ... from working properly, the body cannot regulate its temperature as it should. Nerve damage can also cause ...

  8. Diabetes and nerve damage

    MedlinePlus

    Diabetic neuropathy; Diabetes - neuropathy; Diabetes - peripheral neuropathy ... In people with diabetes, the body's nerves can be damaged by decreased blood flow and a high blood sugar level. This condition is ...

  9. 7 CFR 1945.25 - Relationship between FmHA or its successor agency under Public Law 103-354 and FEMA.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... under Public Law 103-354 and FEMA. 1945.25 Section 1945.25 Agriculture Regulations of the Department of... Public Law 103-354 and FEMA. (a) General. When a major disaster or emergency declaration is made by the... FmHA or its successor agency under Public Law 103-354 on losses and damages caused by an unusual...

  10. Conservation Laws with Dissipation,

    DTIC Science & Technology

    1980-07-01

    smooth, due to the formation of shock waves. However, global solutions exist in the class of functions of bounded variation ,/in the sense of Tonelli...hyperbolic conservation law (2.2) ut + f(u)x -0 The Cauchy problem for (2.2), with initial data u(x,O), of bounded variation , admits a solution in the class...BV of functions of bounded variation ,.in the sense of Tonelli-Cesari. No gain would be made by assuming that u(x,O) is smoother, even analytic! In

  11. Law of the sea

    SciTech Connect

    Richardson, E.L.

    1981-03-01

    The Law of the Sea Treaty is designed as an umbrella treaty to provide a general legal framework for dealing with sources of marine pollution, 85% of which are land-based. Unlike smaller bodies of water, the oceans may be too large to reverse the effects of pollution beyond a certain point. Besides land-based sources, the treaty addresses pollution from seabed activities, dumping, airborne pollutants, and vessels. Basic jurisdictional rights and duties are established that protect navigational freedoms as well as prevent pollution. (DCK)

  12. On integrable conservation laws.

    PubMed

    Arsie, Alessandro; Lorenzoni, Paolo; Moro, Antonio

    2015-01-08

    We study normal forms of scalar integrable dispersive (not necessarily Hamiltonian) conservation laws, via the Dubrovin-Zhang perturbative scheme. Our computations support the conjecture that such normal forms are parametrized by infinitely many arbitrary functions that can be identified with the coefficients of the quasi-linear part of the equation. Moreover, in general, we conjecture that two scalar integrable evolutionary partial differential equations having the same quasi-linear part are Miura equivalent. This conjecture is also consistent with the tensorial behaviour of these coefficients under general Miura transformations.

  13. On integrable conservation laws

    PubMed Central

    Arsie, Alessandro; Lorenzoni, Paolo; Moro, Antonio

    2015-01-01

    We study normal forms of scalar integrable dispersive (not necessarily Hamiltonian) conservation laws, via the Dubrovin–Zhang perturbative scheme. Our computations support the conjecture that such normal forms are parametrized by infinitely many arbitrary functions that can be identified with the coefficients of the quasi-linear part of the equation. Moreover, in general, we conjecture that two scalar integrable evolutionary partial differential equations having the same quasi-linear part are Miura equivalent. This conjecture is also consistent with the tensorial behaviour of these coefficients under general Miura transformations. PMID:25568614

  14. Evolution of dietary antioxidants.

    PubMed

    Benzie, Iris F F

    2003-09-01

    Oxygen is vital for most organisms but, paradoxically, damages key biological sites. Oxygenic threat is met by antioxidants that evolved in parallel with our oxygenic atmosphere. Plants employ antioxidants to defend their structures against reactive oxygen species (ROS; oxidants) produced during photosynthesis. The human body is exposed to these same oxidants, and we have also evolved an effective antioxidant system. However, this is not infallible. ROS breach defences, oxidative damage ensues, accumulates with age, and causes a variety of pathological changes. Plant-based, antioxidant-rich foods traditionally formed the major part of the human diet, and plant-based dietary antioxidants are hypothesized to have an important role in maintaining human health. This hypothesis is logical in evolutionary terms, especially when we consider the relatively hypoxic environment in which humans may have evolved. In this paper, the human diet is discussed briefly in terms of its evolutionary development, different strategies of antioxidant defence are outlined, and evolution of dietary antioxidants is discussed from the perspectives of plant need and our current dietary requirements. Finally, possibilities in regard to dietary antioxidants, evolution, and human health are presented, and an evolutionary cost-benefit analysis is presented in relation to why we lost the ability to make ascorbic acid (vitamin C) although we retained an absolute requirement for it.

  15. Simple model of self-organized biological evolution

    SciTech Connect

    de Boer, J.; Derrida, B.; Flyvbjerg, H.; Jackson, A.D.; Wettig, T. The Isaac Newton Institute for Mathematical Sciences, 20 Clarkson Road, Cambridge, CB4 0EH Laboratoire de Physique Statistique, Ecole Normale Superieure, 24 rue Lhomond, F-75005 Paris Service de Physique Theorique, Centre de Etudes Nucleaires de Saclay, F-91191, Gif-Sur-Yvette CONNECT, The Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen )

    1994-08-08

    We give an exact solution of a recently proposed self-organized critical model of biological evolution. We show that the model has a power law distribution of durations of coevolutionary avalanches'' with a mean field exponent 3/2. We also calculate analytically the finite size effects which cut off this power law at times of the order of the system size.

  16. Simple model of self-organized biological evolution

    NASA Astrophysics Data System (ADS)

    de Boer, Jan; Derrida, Bernard; Flyvbjerg, Henrik; Jackson, Andrew D.; Wettig, Tilo

    1994-08-01

    We give an exact solution of a recently proposed self-organized critical model of biological evolution. We show that the model has a power law distribution of durations of coevolutionary ``avalanches'' with a mean field exponent 3/2. We also calculate analytically the finite size effects which cut off this power law at times of the order of the system size.

  17. Alcohol and the law.

    PubMed

    Karasov, Ariela O; Ostacher, Michael J

    2014-01-01

    Society has had an interest in controlling the production, distribution, and use of alcohol for millennia. The use of alcohol has always had consequences, be they positive or negative, and the role of government in the regulation of alcohol is now universal. This is accomplished at several levels, first through controls on production, importation, distribution, and use of alcoholic beverages, and second, through criminal laws, the aim of which is to address the behavior of users themselves. A number of interventions and policies reduce alcohol-related consequences to society by regulating alcohol pricing, targeting alcohol-impaired driving, and limiting alcohol availability. The legal system defines criminal responsibility in the context of alcohol use, as an enormous percentage of violent crime and motor death is associated with alcohol intoxication. In recent years, recovery-oriented policies have aimed to expand social supports for recovery and to improve access to treatment for substance use disorders within the criminal justice system. The Affordable Care Act, also know as "ObamaCare," made substantial changes to access to substance abuse treatment by mandating that health insurance include services for substance use disorders comparable to coverage for medical and surgical treatments. Rather than a simplified "war on drugs" approach, there appears to be an increasing emphasis on evidence-based policy development that approaches alcohol use disorders with hope for treatment and prevention. This chapter focuses on alcohol and the law in the United States.

  18. Alexander's Law revisited.

    PubMed

    Jeffcoat, Benjamin; Shelukhin, Alexander; Fong, Alex; Mustain, William; Zhou, Wu

    2008-07-01

    Alexander's Law states that the slow-phase velocity of the nystagmus caused by unilateral vestibular lesion increases with gaze in the beat direction. Two studies have shown that this gaze effect is generalized to the nystagmus caused by unilateral cold water irrigation. This indicates that the gaze effect is not the result of central changes associated with a peripheral lesion but rather because of unilateral vestibular peripheral inhibition. In this study, we show that there is a similar gaze effect on the nystagmus produced by unilateral warm water ear irrigation. Furthermore, we examined the two hypotheses of Alexander's Law proposed in the two studies. One hypothesis is based on the gaze-dependent modulation of the vestibulo-ocular reflex (VOR) response to unbalanced canal input. The other hypothesis, however, is based on the leaky neural integrator caused by unilateral vestibular peripheral inhibition. These two hypotheses predict the same gaze effect on the nystagmus produced by cold water irrigation, but opposite gaze effects on the nystagmus produced by warm water irrigation. Our results support the first hypothesis and suggest that the second hypothesis needs to be modified.

  19. Lightning Scaling Laws Revisited

    NASA Technical Reports Server (NTRS)

    Boccippio, D. J.; Arnold, James E. (Technical Monitor)

    2000-01-01

    Scaling laws relating storm electrical generator power (and hence lightning flash rate) to charge transport velocity and storm geometry were originally posed by Vonnegut (1963). These laws were later simplified to yield simple parameterizations for lightning based upon cloud top height, with separate parameterizations derived over land and ocean. It is demonstrated that the most recent ocean parameterization: (1) yields predictions of storm updraft velocity which appear inconsistent with observation, and (2) is formally inconsistent with the theory from which it purports to derive. Revised formulations consistent with Vonnegut's original framework are presented. These demonstrate that Vonnegut's theory is, to first order, consistent with observation. The implications of assuming that flash rate is set by the electrical generator power, rather than the electrical generator current, are examined. The two approaches yield significantly different predictions about the dependence of charge transfer per flash on storm dimensions, which should be empirically testable. The two approaches also differ significantly in their explanation of regional variability in lightning observations.

  20. Fault tolerant control laws

    NASA Technical Reports Server (NTRS)

    Ly, U. L.; Ho, J. K.

    1986-01-01

    A systematic procedure for the synthesis of fault tolerant control laws to actuator failure has been presented. Two design methods were used to synthesize fault tolerant controllers: the conventional LQ design method and a direct feedback controller design method SANDY. The latter method is used primarily to streamline the full-state Q feedback design into a practical implementable output feedback controller structure. To achieve robustness to control actuator failure, the redundant surfaces are properly balanced according to their control effectiveness. A simple gain schedule based on the landing gear up/down logic involving only three gains was developed to handle three design flight conditions: Mach .25 and Mach .60 at 5000 ft and Mach .90 at 20,000 ft. The fault tolerant control law developed in this study provides good stability augmentation and performance for the relaxed static stability aircraft. The augmented aircraft responses are found to be invariant to the presence of a failure. Furthermore, single-loop stability margins of +6 dB in gain and +30 deg in phase were achieved along with -40 dB/decade rolloff at high frequency.

  1. A scaling law of radial gas distribution in disk galaxies

    NASA Technical Reports Server (NTRS)

    Wang, Zhong

    1990-01-01

    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).

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

    PubMed

    Lening Zhang; Jianhong Liu

    2007-10-01

    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.

  3. [Environmental damage assessment: international regulations and revelation to China].

    PubMed

    Zhang, Hong-zhen; Cao, Dong; Yu, Fang; Wang, Jin-nan; Qi, Ji; Jia, Qian; Zhang, Tian-zhu; Luo, Yong-ming

    2013-05-01

    As the whole society gradually realizes the scarcity of nature resources and environmental value, countries all over the world have evolved and improved the system of environmental damage assessment through the practices of pollution prevention and ecological environmental protection. On one hand, in the research prospective, the practices of environmental damage assessment brought new challenges to environmental law, environmental economics, environmental science, environmental engineering, etc. On the other hand, they constantly promoted and developed relevant laws and regulations, techniques, working mechanism, and guidelines on procedure in practice. On the hasis of comparison and analysis of international practices and experiences from US, EU, and Japan, etc., this article identified relevant concepts, content, and scope of environmental damage assessment, and presented its scientific positioning and development direction. At present, both theory and practice of environmental damage assessment in China are in their infancy period. Considering current environmental situation and socioeconomic development features of China, learning international practices and experiences and raising the orientation of environmental damage assessment have great meaning in exploring the suitable environmental damage assessment system.

  4. What is a Physical Law?

    NASA Astrophysics Data System (ADS)

    Lange, Marc

    2008-10-01

    Laws of nature are distinguished from logical and mathematical truths, on the one hand, and from ``accidental facts'' (such as that every atom in some particular spatiotemporal region is lead), on the other hand. What is it for some fact to be a law? Roughly speaking, laws, unlike accidents, would still have held no matter what -- even if other things had been different. For instance, if Earth's axis had been tipped differently, then various accidental features of Earth's seasons would have been different, but the laws of nature would have been no different. However, this way of drawing the distinction between laws and accidents threatens to appeal to the very distinction that it is supposed to illuminate: some fact p is a law if and only if for any hypothetical state of affairs q that is logically consistent with the laws, p would still have held had q been the case. (The risk of circularity arises from the requirement that q be logically consistent with the laws.) In this talk, I will explain how to avoid referring to lawhood on the right side of this ``if and only if.'' The resulting account of the distinction between laws and accidents nicely explains the sense in which things ``cannot'' break the laws.

  5. Assessing Tropical Cyclone Damage

    NASA Astrophysics Data System (ADS)

    Done, J.; Czajkowski, J.

    2012-12-01

    Landfalling tropical cyclones impact large coastal and inland areas causing direct damage due to winds, storm-surge flooding, tornadoes, and precipitation; as well as causing substantial indirect damage such as electrical outages and business interruption. The likely climate change impact of increased tropical cyclone intensity, combined with increases in exposure, bring the possibility of increased damage in the future. A considerable amount of research has focused on modeling economic damage due to tropical cyclones, and a series of indices have been developed to assess damages under climate change. We highlight a number of ways this research can be improved through a series of case study analyses. First, historical loss estimates are revisited to properly account for; time, impacted regions, the source of damage by type, and whether the damage was direct/indirect and insured/uninsured. Second, the drivers of loss from both the socio-economic and physical side are examined. A case is made to move beyond the use of maximum wind speed to more stable metrics and the use of other characteristics of the wind field such as direction, degree of gustiness, and duration is explored. A novel approach presented here is the potential to model losses directly as a function of climate variables such as sea surface temperature, greenhouse gases, and aerosols. This work is the first stage in the development of a tropical cyclone loss model to enable projections of losses under scenarios of both socio-economic change (such as population migration or altered policy) and physical change (such as shifts in tropical cyclone activity one from basin to another or within the same basin).

  6. Continuum damage model for bioresorbable magnesium alloy devices - Application to coronary stents.

    PubMed

    Gastaldi, D; Sassi, V; Petrini, L; Vedani, M; Trasatti, S; Migliavacca, F

    2011-04-01

    The main drawback of a conventional stenting procedure is the high risk of restenosis. The idea of a stent that "disappears" after having fulfilled its mission is very intriguing and fascinating, since it can be expected that the stent mass decreases in time to allow the gradual transmission of the mechanical load to the surrounding tissues owing to controlled dissolution by corrosion. Magnesium and its alloys are appealing materials for designing biodegradable stents. The objective of this work is to develop, in a finite element framework, a model of magnesium degradation that is able to predict the corrosion rate, thus providing a valuable tool for the design of bioresorbable stents. Continuum damage mechanics is suitable for modeling several damage mechanisms, including different types of corrosion. In this study, the damage is assumed to be the superposition of stress corrosion and uniform microgalvanic corrosion processes. The former describes the stress-mediated localization of the corrosion attack through a stress-dependent evolution law, while the latter affects the free surface of the material exposed to an aggressive environment. Comparisons with experimental tests show that the developed model can reproduce the behavior of different magnesium alloys subjected to static corrosion tests. The study shows that parameter identification for a correct calibration of the model response on the results of uniform and stress corrosion experimental tests is reachable. Moreover, three-dimensional stenting procedures accounting for interaction with the arterial vessel are simulated, and it is shown how the proposed modeling approach gives the possibility of accounting for the combined effects of an aggressive environment and mechanical loading.

  7. The law of mortality revisited: interspecies comparisons of mortality.

    PubMed

    Olshansky, S J

    2010-01-01

    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.

  8. Reducing Radiation Damage

    SciTech Connect

    Blankenbecler, Richard

    2006-06-05

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

  9. Numerical Simulation for Predicting Fatigue Damage Progress in Notched CFRP Laminates by Using Cohesive Elements

    NASA Astrophysics Data System (ADS)

    Okabe, Tomonaga; Yashiro, Shigeki

    This study proposes the cohesive zone model (CZM) for predicting fatigue damage growth in notched carbon-fiber-reinforced composite plastic (CFRP) cross-ply laminates. In this model, damage growth in the fracture process of cohesive elements due to cyclic loading is represented by the conventional damage mechanics model. We preliminarily investigated whether this model can appropriately express fatigue damage growth for a circular crack embedded in isotropic solid material. This investigation demonstrated that this model could reproduce the results with the well-established fracture mechanics model plus the Paris' law by tuning adjustable parameters. We then numerically investigated the damage process in notched CFRP cross-ply laminates under tensile cyclic loading and compared the predicted damage patterns with those in experiments reported by Spearing et al. (Compos. Sci. Technol. 1992). The predicted damage patterns agreed with the experiment results, which exhibited the extension of multiple types of damage (e.g., splits, transverse cracks and delaminations) near the notches.

  10. Scaling laws in cognitive sciences.

    PubMed

    Kello, Christopher T; Brown, Gordon D A; Ferrer-I-Cancho, Ramon; Holden, John G; Linkenkaer-Hansen, Klaus; Rhodes, Theo; Van Orden, Guy C

    2010-05-01

    Scaling laws are ubiquitous in nature, and they pervade neural, behavioral and linguistic activities. A scaling law suggests the existence of processes or patterns that are repeated across scales of analysis. Although the variables that express a scaling law can vary from one type of activity to the next, the recurrence of scaling laws across so many different systems has prompted a search for unifying principles. In biological systems, scaling laws can reflect adaptive processes of various types and are often linked to complex systems poised near critical points. The same is true for perception, memory, language and other cognitive phenomena. Findings of scaling laws in cognitive science are indicative of scaling invariance in cognitive mechanisms and multiplicative interactions among interdependent components of cognition.

  11. Natural resource damages: A legal, economic and policy overview

    SciTech Connect

    Connaughton, J.L.

    1995-12-31

    Natural resource damages liability is a major development in environmental law. Government authorities are increasingly seeking damage claims for injury to natural resources, invoking the natural resource damages (NRD) provisions of the federal Superfund statute and the Oil Pollution Act. The number of Claims asserted is increasing, and the amounts sought range to hundreds of millions of dollars, with some claims exceeding $1 billion. Some assert that the federal NRD program is an awakening sleeping giant that could threaten to rival the Superfund cleanup program in cost and the potential for imposing far-reaching liabilities on a wide range of businesses as well as the federal government. Lawyers, economists, and other experts on NRD have become fully engaged in comprehensive analyses of the legal, economic and policy issues presented by NRD claims, including a full review of the NRD litigating record. Many critics find that existing NRD law and practice is flawed; produces excessive liability claims, skewed incentives and economic waste; and urgently needs reform. Changes have been recommended to improve the law and refocus the NRD program on achieving cost-effective restoration of injured natural resources. These analytical endeavors are especially timely because Congress is currently considering significant changes in NRD law. This overview will provide a brief background summary of the NRD program and highlight some of the central legal and scientific issues facing government policy makers and litigants in NRD cases.

  12. Horrocks's bogus law

    NASA Astrophysics Data System (ADS)

    Hughes, David W.

    2005-02-01

    In the early 17th century it was generally accepted that the size of a planet was related to its distance from the Sun. The Lancashire astronomer Jeremiah Horrocks (1619-42) took this a stage further. For the planets known at the time he suggested that the planet-Sun distance was about 15 000 times the planetary radius. This was equivalent to saying that all the planetary spheres subtended an angle of 28 arcsec at the Sun. This so called ``Horrocks's Law'' was confirmed by his Sunday 24 November 1639 (old style) measurement of the angular diameter of the transiting Venus. It leads to a solar parallax of 14 arcsec, a value considered rather small at the time, but refreshingly close to the modern value of about 8.798 arcsec.

  13. Kirschmann's Fourth Law.

    PubMed

    Bosten, J M; Mollon, J D

    2012-01-15

    Kirschmann's Fourth Law states that the magnitude of simultaneous color contrast increases with the saturation of the inducing surround, but that the rate of increase reduces as saturation increases. Others since Kirschmann have agreed and disagreed. Here we show that the form of the relationship between simultaneous color contrast and inducer saturation depends on the method of measurement. Functions were measured by four methods: (i) asymmetric matching with a black surround, (ii) asymmetric matching with a surround metameric to equal energy white, (iii) dichoptic matching, and (iv) nulling an induced sinusoidal modulation. Results from the asymmetric matching conditions agreed with Kirschmann, whereas results from nulling and from dichoptic matching showed a more linear increase in simultaneous contrast with the saturation of the inducer. We conclude that the method certainly affects the conclusions reached, and that there may not be any "fair" way of measuring simultaneous contrast.

  14. LAWS hurricane studies

    NASA Technical Reports Server (NTRS)

    Molinari, John

    1995-01-01

    The Laser Atmospheric Wind Sounder (LAWS) has recently been deselected from the Earth Observing System (EOS). A broad range of orbital altitudes and laser power are being considered for future wind lidar missions. As a result, as was anticipated in the proposed work, it may be impossible to meaningfully study tropical cyclones with lidar wind data because data coverage (i.e., swath width) is insufficient. Research on this grant has focused on how to maximize the benefits of a wind lidar regardless of the choice of platform or laser. Our studies have shown that major unsolved problems in tropical meteorology relate to the structure, dynamics, and role in tropical cyclogenesis of 'easterly waves'. These disturbances exist almost everywhere in the global subtropics. Results are described that focus upon easterly wave impacts on eastern Pacific tropical cyclogenesis. The availability of wind lidar data would create tremendous opportunities for the study of these waves and their role in the general circulation.

  15. Videofile for Law Enforcement

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Components of a videotape storage and retrieval system originally developed for NASA have been adapted as a tool for law enforcement agencies. Ampex Corp., Redwood City, Cal., built a unique system for NASA-Marshall. The first application of professional broadcast technology to computerized record-keeping, it incorporates new equipment for transporting tapes within the system. After completing the NASA system, Ampex continued development, primarily to improve image resolution. The resulting advanced system, known as the Ampex Videofile, offers advantages over microfilm for filing, storing, retrieving, and distributing large volumes of information. The system's computer stores information in digital code rather than in pictorial form. While microfilm allows visual storage of whole documents, it requires a step before usage--developing the film. With Videofile, the actual document is recorded, complete with photos and graphic material, and a picture of the document is available instantly.

  16. The phenomenological mechanochemistry of damage and radial cracking

    NASA Astrophysics Data System (ADS)

    Grinfeld, Michael

    2017-01-01

    Traditional damage theory deals with distributed microcracks rather than with individual cracks. In its simplest form, this theory adds just one additional parameter to the set of classical thermodynamic parameters of deformable solids like strain and temperature. Basically, the traditional damage theory reflects only one experimental observation: The elastic moduli become smaller with growing damage. Contrary to the traditional damage theory, the Phenomenological Mechanochemistry of Damage (PMD) uses an energetic approach; it includes, in addition to the bulk elastic energy, the energy associated with braking/recovery of chemical bonds. Therefore, in addition to the elasticity equations, it includes the equation describing evolution/dynamics of chemical bonds. With the minimum amount of physically transparent assumptions, it allows the reproduction of radial cracking patterns that are often observed in experiments and nature. In this paper, we review some earlier results and present the novel ones with emphasis on the electro- or magnetostatics ponderomotive forces.

  17. Crumpling Damaged Graphene

    PubMed Central

    Giordanelli, I.; Mendoza, M.; Andrade Jr., J. S.; Gomes, M. A. F.; Herrmann, H. J.

    2016-01-01

    Through molecular mechanics we find that non-covalent interactions modify the fractality of crumpled damaged graphene. Pristine graphene membranes are damaged by adding random vacancies and carbon-hydrogen bonds. Crumpled membranes exhibit a fractal dimension of 2.71 ± 0.02 when all interactions between carbon atoms are considered, and 2.30 ± 0.05 when non-covalent interactions are suppressed. The transition between these two values, obtained by switching on/off the non-covalent interactions of equilibrium configurations, is shown to be reversible and independent on thermalisation. In order to explain this transition, we propose a theoretical model that is compatible with our numerical findings. Finally, we also compare damaged graphene membranes with other crumpled structures, as for instance polymerised membranes and paper sheets, that share similar scaling properties. PMID:27173442

  18. Damage Tolerance Assessment Branch

    NASA Technical Reports Server (NTRS)

    Walker, James L.

    2013-01-01

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

  19. Classical and quantum Malus laws

    NASA Astrophysics Data System (ADS)

    Wódkiewicz, Krzysztof

    1995-04-01

    The classical and the quantum Malus laws for light and spin are discussed. It is shown that for spin 1/2, the quantum Malus law is equivalent in form to the classical Malus law provided the statistical average involves a quasidistribution function that can become negative. A generalization of Malus's law for arbitrary spin s is obtained in the form of a Feynman path-integral representation for the Malus amplitude. The classical limit of the Malus amplitude for s-->∞ is discussed.

  20. A method of damage mechanics analysis for solder material

    SciTech Connect

    Fang, H.E.; Chow, C.L.; Yang, Fan

    1997-06-01

    This paper presents as a method of damage mechanics analysis for solder joint material stressed to extensive plastic deformation. The material chosen for the current work is the 60Sn-40Pb eutectic alloy due to its wide use. The analysis is based on the thermodynamic theory of irreversible processes. With the introduction of a set of internal state variables, known as damage variables, and a damage effect tensor, a damage dissipative potential function is proposed to enable the formulation of the constitutive equations of elasticity and plasticity coupled with damage. The equations of damage evolution are also derived to monitor damage initiation and growth. Before a damage analysis can be performed with a finite element analysis, the mechanical properties of the chosen solder joint material and its damage variables must first be determined. A method of experimental analysis was developed and used to successfully measure the highly strain sensitive 60Sn-40Pb solder material. The measured properties are presented and various characteristics of the solder material are examined and discussed. 7 refs., 8 figs.

  1. Damage Pre-Cursors Based Assessment of Accrued Thermo-Mechanical Damage and Remaining Useful Life in Field Deployed Electronics

    NASA Astrophysics Data System (ADS)

    Lall, Pradeep; Harsha, Mahendra; Goebel, Kai; Jones, Jim

    Field deployed electronics may accrue damage due to environmental exposure and usage after finite period of service but may not often have any o-indicators of failure such as cracks or delamination. A method to interrogate the damage state of field deployed electronics in the pre-failure space may allow insight into the damage initiation, progression, and remaining useful life of the deployed system. Aging has been previously shown to effect the reliability and constitutive behavior of second-level leadfree interconnects. Prognostication of accrued damage and assessment of residual life can provide valuable insight into impending failure. In this paper, field deployed parts have been extracted and prognosticated for accrued damage and remaining useful life in an anticipated future deployment environment. A subset of the field deployed parts have been tested to failure in the anticipated field deployed environment to validate the assessment of remaining useful life. In addition, some parts have been subjected to additional known thermo-mechanical stresses and the incremental damage accrued validated with respect to the amount of additional damage imposed on the assemblies. The presented methodology uses leading indicators of failure based on micro-structural evolution of damage to identify accrued damage in electronic systems subjected to sequential stresses of thermal aging and thermal cycling. Damage equivalency methodologies have been developed to map damage accrued in thermal aging to the reduction in thermo-mechanical cyclic life based on damage proxies. The expected error with interrogation of system state and assessment of residual life has been quantified. Prognostic metrics including α-λmetric, sample standard deviation, mean square error, mean absolute percentage error, average bias, relative accuracy, and cumulative relative accuracy have been used to compare the performance of the damage proxies.

  2. Adaptive Neural Network Nonparametric Identifier With Normalized Learning Laws.

    PubMed

    Chairez, Isaac

    2016-04-05

    This paper addresses the design of a normalized convergent learning law for neural networks (NNs) with continuous dynamics. The NN is used here to obtain a nonparametric model for uncertain systems described by a set of ordinary differential equations. The source of uncertainties is the presence of some external perturbations and poor knowledge of the nonlinear function describing the system dynamics. A new adaptive algorithm based on normalized algorithms was used to adjust the weights of the NN. The adaptive algorithm was derived by means of a nonstandard logarithmic Lyapunov function (LLF). Two identifiers were designed using two variations of LLFs leading to a normalized learning law for the first identifier and a variable gain normalized learning law. In the case of the second identifier, the inclusion of normalized learning laws yields to reduce the size of the convergence region obtained as solution of the practical stability analysis. On the other hand, the velocity of convergence for the learning laws depends on the norm of errors in inverse form. This fact avoids the peaking transient behavior in the time evolution of weights that accelerates the convergence of identification error. A numerical example demonstrates the improvements achieved by the algorithm introduced in this paper compared with classical schemes with no-normalized continuous learning methods. A comparison of the identification performance achieved by the no-normalized identifier and the ones developed in this paper shows the benefits of the learning law proposed in this paper.

  3. The Simulated Law Firm and Other Contemporary Law Simulations

    ERIC Educational Resources Information Center

    Hollander, Patricia A.

    1978-01-01

    Various modes of simulations currently used in law schools are reviewed, including the Simulated Law Firm (SLF) at SUNY Buffalo and various computer-aided teaching programs. Simulation and computer use in the legal profession is reported, followed by a historical description of simulations in teaching and research. Its effectiveness as a teaching…

  4. Simulating the Law: Experiential "Teachniques" in the Modern Law Curricula

    ERIC Educational Resources Information Center

    Daly, Yvonne; Higgins, Noelle

    2010-01-01

    The concept of arguing aspects of legal scenarios in order to facilitate student learning within the law curriculum originated in the vocational Inns of Court in fourteenth-century England. Nowadays, simulations of court proceedings, such as moot courts and mock trials, are widely employed as educational tools in law modules in third-level…

  5. Library Laws Handbook: State Laws Relating to Michigan Libraries.

    ERIC Educational Resources Information Center

    Michigan Library, Lansing.

    This document presents excerpts and copies of state laws relating to Michigan libraries. The following are included: the Preamble of the Constitution of Michigan of 1963; Legislative Council Act (excerpt); Incompatible Public Offices; Freedom of Information Act; Open Meetings Act; Laws, Documents, and Reports (excerpts); Administrative Procedures…

  6. Bijuralism in Law's Empire and in Law's Cosmos.

    ERIC Educational Resources Information Center

    Kasirer, Nicholas

    2002-01-01

    Using the example of McGill University's bijural program, explores how teaching the common and civil law traditions together provides an opportunity to teach in law's "cosmos" rather than its "empire," so that a bijural legal education can plainly and confidently ally itself with the great university tradition of prizing…

  7. Experimental Verification of Boyle's Law and the Ideal Gas Law

    ERIC Educational Resources Information Center

    Ivanov, Dragia Trifonov

    2007-01-01

    Two new experiments are offered concerning the experimental verification of Boyle's law and the ideal gas law. To carry out the experiments, glass tubes, water, a syringe and a metal manometer are used. The pressure of the saturated water vapour is taken into consideration. For educational purposes, the experiments are characterized by their…

  8. Teaching of Administrative Law in the New Grade of Law

    ERIC Educational Resources Information Center

    Domínguez Alonso, Patricia

    2012-01-01

    The teaching of Administrative Law in the new grade of law poses numerous challenges and opportunities in the new model of Bologna. It's really important work of research and students in class presentations. It is also important to motivate students to study the issues and cases brought before classes and to use virtual platforms to interact with…

  9. Empirical Scaling Laws of Rocket Exhaust Cratering

    NASA Technical Reports Server (NTRS)

    Donahue, Carly M.; Metzger, Philip T.; Immer, Christopher D.

    2005-01-01

    When launching or landing a space craft on the regolith of a terrestrial surface, special attention needs to be paid to the rocket exhaust cratering effects. If the effects are not controlled, the rocket cratering could damage the spacecraft or other surrounding hardware. The cratering effects of a rocket landing on a planet's surface are not understood well, especially for the lunar case with the plume expanding in vacuum. As a result, the blast effects cannot be estimated sufficiently using analytical theories. It is necessary to develop physics-based simulation tools in order to calculate mission-essential parameters. In this work we test out the scaling laws of the physics in regard to growth rate of the crater depth. This will provide the physical insight necessary to begin the physics-based modeling.

  10. Analyses of the cell mechanical damage during microinjection.

    PubMed

    Liu, Fei; Wu, Dan; Wu, Xiaoyong; Chen, Ken

    2015-02-04

    The microinjection is an essential technique to introduce foreign materials into biological cells. The soft cell is inevitably ruptured by the microinjector during microinjection. We discuss the way to reduce the mechanical damage by analyzing the control parameters during microinjection. The computational model is developed with the dissipative particle dynamics to simulate the soft mechanical properties of biological cells. The cell model contains the membrane networks, the internal cytoskeleton, crosslink proteins, motors and their functions. The weak power law rheology verifies our computational model. The number of ruptured bonds is used to describe the extent of the mechanical damage that the cell experiences during microinjection. Some experiments are conducted on the Zebrafish embryos. Both the simulation works and experimental results show that the size, shape of the microinjector tip, and the injection velocity have a significant influence on the cell damage. A small, sharp microinjector with a high velocity can reduce the mechanical damage.

  11. Public health law research: exploring law in public health systems.

    PubMed

    Ibrahim, Jennifer K; Burris, Scott; Hays, Scott

    2012-11-01

    The importance of law in the organization and operation of public health systems has long been a matter of interest to public health lawyers and practitioners, but empirical research on law as a factor in health system performance has been limited in quantity and sophistication. The emergence of Public Health Law Research and Public Health Systems and Services Research within a coordinated effort to strengthen public health research and practice has dramatically changed matters. This article introduces Public Health Law Research as an integral part of Public Health Systems and Services Research, discusses the challenges of integrating the 2 fields, and highlights 2 examples of current research that demonstrate the benefits of an integrated approach to improve the use of law in public health practice.

  12. Displacement Cascade Damage Production in Metals

    SciTech Connect

    Stoller, Roger E; Malerba, Lorenzo; Nordlund, Kai

    2015-01-01

    Radiation-induced changes in microstructure and mechanical properties in structural materials are the result of a complex set of physical processes initiated by the collision between an energetic particle (neutron or ion) and an atom in the lattice. This primary damage event is called an atomic displacement cascade. The simplest description of a displacement cascade is to view it as a series of many billiard-ball-like elastic collisions among the atoms in the material. This chapter describes the formation and evolution of this primary radiation damage mechanism 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 relevant variables such as cascade energy and irradiation temperature is discussed, and defect formation in different materials is compared.

  13. Secondary factors influencing cascade damage formation

    NASA Astrophysics Data System (ADS)

    Stoller, Roger E.; Guiriec, Sylvain G.

    2004-08-01

    Primary cascade damage production in iron has been extensively investigated by molecular dynamics, and the average defect production as a function of cascade energy and temperature is well characterized. However, preliminary results indicate several factors alter `normal' cascade evolution, leading to quite different defect production behavior. Further investigation of three such factors has been carried out: (1) primary knock-on atom (PKA) direction, (2) nearby free surfaces, and (3) pre-existing effects. Results of the investigation confirm these factors significantly impact damage production. Effects include: enhanced defect survival for PKA directions lying in close-packed {1 1 0} planes, increased point defect clustering and larger defect clusters in cascades initiated near a surface, and reduced defect survival in material containing defects. The origin and implications of these effects are discussed relative to the interpretation of certain experimental observations and parameters used in other modeling studies.

  14. Damage characterization in concrete using diffuse ultrasound

    NASA Astrophysics Data System (ADS)

    Shokouhi, Parisa; Niederleithinger, Ernst

    2012-05-01

    Diffuse ultrasonic measurements were used to characterize the state of stress-induced damage (volumetric microcracking) in concrete specimens. The test specimens were subjected to cycles of stepwise uniaxial compression. At each step, the loading (stress- or strain-controlled) was held constant and a series of ultrasonic measurements parallel and perpendicular to the loading were obtained. Unusually long signals were recorded, so that the diffuse ultrasonic regime tailing the coherent field could be studied. In the diffuse regime, the measured ultrasonic response is a superposition of reflections from scatters within concrete and thus, very sensitive to the changes in concrete microstructure. Using Coda Wave Interferometry (CWI), the evolution of diffuse velocity with the increasing load was monitored. The rate of change in the diffusion velocities was shown to be a good indication of the state of (low to medium intensity) damage in concrete.

  15. Progressive Damage Analysis of Bonded Composite Joints

    NASA Technical Reports Server (NTRS)

    Leone, Frank A., Jr.; Girolamo, Donato; Davila, Carlos G.

    2012-01-01

    The present work is related to the development and application of progressive damage modeling techniques to bonded joint technology. The joint designs studied in this work include a conventional composite splice joint and a NASA-patented durable redundant joint. Both designs involve honeycomb sandwich structures with carbon/epoxy facesheets joined using adhesively bonded doublers.Progressive damage modeling allows for the prediction of the initiation and evolution of damage within a structure. For structures that include multiple material systems, such as the joint designs under consideration, the number of potential failure mechanisms that must be accounted for drastically increases the complexity of the analyses. Potential failure mechanisms include fiber fracture, intraply matrix cracking, delamination, core crushing, adhesive failure, and their interactions. The bonded joints were modeled using highly parametric, explicitly solved finite element models, with damage modeling implemented via custom user-written subroutines. Each ply was discretely meshed using three-dimensional solid elements. Layers of cohesive elements were included between each ply to account for the possibility of delaminations and were used to model the adhesive layers forming the joint. Good correlation with experimental results was achieved both in terms of load-displacement history and the predicted failure mechanism(s).

  16. Loss and damage

    NASA Astrophysics Data System (ADS)

    Huq, Saleemul; Roberts, Erin; Fenton, Adrian

    2013-11-01

    Loss and damage is a relative newcomer to the climate change agenda. It has the potential to reinvigorate existing mitigation and adaptation efforts, but this will ultimately require leadership from developed countries and enhanced understanding of several key issues, such as limits to adaptation.

  17. Coping with brain damage

    NASA Technical Reports Server (NTRS)

    Waring, W.

    1974-01-01

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

  18. Modifying Radiation Damage

    PubMed Central

    Kim, Kwanghee; McBride, William H.

    2011-01-01

    Radiation leaves a fairly characteristic footprint in biological materials, but this is rapidly all but obliterated by the canonical biological responses to the radiation damage. The innate immune recognition systems that sense “danger” through direct radiation damage and through associated collateral damage set in motion a chain of events that, in a tissue compromised by radiation, often unwittingly result in oscillating waves of molecular and cellular responses as tissues attempt to heal. Understanding “nature’s whispers” that inform on these processes will lead to novel forms of intervention targeted more precisely towards modifying them in an appropriate and timely fashion so as to improve the healing process and prevent or mitigate the development of acute and late effects of normal tissue radiation damage, whether it be accidental, as a result of a terrorist incident, or of therapeutic treatment of cancer. Here we attempt to discuss some of the non-free radical scavenging mechanisms that modify radiation responses and comment on where we see them within a conceptual framework of an evolving radiation-induced lesion. PMID:20583981

  19. 25 CFR 161.715 - What will BIA do if a trespasser fails to pay penalties, damages and costs?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... LAND AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Trespass Penalties, Damages, and Costs § 161... provided by applicable Navajo Nation law, BIA will: (a) Refuse to issue the permittee a permit for any...

  20. Economics of mining law

    USGS Publications Warehouse

    Long, K.R.

    1995-01-01

    Modern mining law, by facilitating socially and environmentally acceptable exploration, development, and production of mineral materials, helps secure the benefits of mineral production while minimizing environmental harm and accounting for increasing land-use competition. Mining investments are sunk costs, irreversibly tied to a particular mineral site, and require many years to recoup. Providing security of tenure is the most critical element of a practical mining law. Governments owning mineral rights have a conflict of interest between their roles as a profit-maximizing landowner and as a guardian of public welfare. As a monopoly supplier, governments have considerable power to manipulate mineral-rights markets. To avoid monopoly rent-seeking by governments, a competitive market for government-owned mineral rights must be created by artifice. What mining firms will pay for mineral rights depends on expected exploration success and extraction costs. Landowners and mining firms will negotlate respective shares of anticipated differential rents, usually allowing for some form of risk sharing. Private landowners do not normally account for external benefits or costs of minerals use. Government ownership of mineral rights allows for direct accounting of social prices for mineral-bearing lands and external costs. An equitable and efficient method is to charge an appropriate reservation price for surface land use, net of the value of land after reclamation, and to recover all or part of differential rents through a flat income or resource-rent tax. The traditional royalty on gross value of production, essentially a regressive income tax, cannot recover as much rent as a flat income tax, causes arbitrary mineral-reserve sterilization, and creates a bias toward development on the extensive margin where marginal environmental costs are higher. Mitigating environmental costs and resolving land-use conflicts require local evaluation and planning. National oversight ensures