WorldWideScience

Sample records for genetic material damage

  1. LSD and Genetic Damage

    Science.gov (United States)

    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)

  2. Material Induced Anisotropic Damage

    NARCIS (Netherlands)

    Niazi, Muhammad Sohail; Wisselink, H.H.; Meinders, Vincent T.; van den Boogaard, Antonius H.; Hora, P.

    2012-01-01

    The anisotropy in damage can be driven by two different phenomena; anisotropic defor-mation state named Load Induced Anisotropic Damage (LIAD) and anisotropic (shape and/or distribution) second phase particles named Material Induced Anisotropic Damage (MIAD). Most anisotropic damage models are based

  3. Damage Atlas for Photographic materials

    Directory of Open Access Journals (Sweden)

    Kristel Van Camp

    2010-11-01

    Full Text Available La conservation des documents photographiques peut nécessiter des interventions préventives ou curatives. Ce choix est guidé par leur état de conservation. Une meilleure connaissance des détériorations est donc cruciale. Le répertoire présenté ici essaie de les classifier selon des caractéristiques spécifiques et leur niveau de gravité. Les différents types de dégradation sont illustrés et décrits avec une terminologie précise. L’auteur propose en regard de ceux-ci l’intervention qui semble la plus appropriée. Ce répertoire s’adresse à toutes les personnes concernées par la photographie, qu’ils soient dans le milieu de la conservation ou dans le domaine artistique, dans les musées ou dans les archives. In order to rescue a damaged photographic object, preventive or conservative actions are needed. Knowing the specific characteristics of different types of damage is crucial. A damage atlas can provide these characteristics. With this atlas the damage can be recognised and appropriate actions can be taken. This damage atlas offers a first attempt to such a characterisation in the field of photography. The damage atlas contains images and the necessary information about damage on photographic material. The atlas with special annotations about the terminology and the grade of the damage is meant for everybody who works with photographic material, as well in museums as in archives.

  4. Genetic damage from low-level and natural background radiation

    International Nuclear Information System (INIS)

    Oftedal, P.

    1988-01-01

    Relevant predictions that have been made of possible low level biological effects on man are reviewed, and the estimate of genetic damage is discussed. It is concluded that in spite of a number of attempts, no clear-cut case of effects in human populations of radiation at natural levels has been demonstrated. The stability of genetic material is dynamic, with damage, repair and selection running as continuous processes. Genetic materials are well protected and are conservative in the extreme, not least because evolution by genetic adaptation is an expensive process: Substitution of one allele A 1 by another A 2 means the death of the whole A 1 population

  5. Radiation damage of structural materials

    CERN Document Server

    Koutsky, Jaroslav

    1994-01-01

    Maintaining the integrity of nuclear power plants is critical in the prevention or control of severe accidents. This monograph deals with both basic groups of structural materials used in the design of light-water nuclear reactors, making the primary safety barriers of NPPs. Emphasis is placed on materials used in VVER-type nuclear reactors: Cr-Mo-V and Cr-Ni-Mo-V steel for RPV and Zr-Nb alloys for fuel element cladding. The book is divided into 7 main chapters, with the exception of the opening one and the chapter providing a phenomenological background for the subject of radiation damage. Ch

  6. Nondestructive characterization of materials damage

    International Nuclear Information System (INIS)

    Dobmann, G.

    1999-01-01

    The paper discusses two examples of application of NDT for early detection of materials damage, or ageing effects. The first case shows the potential of micromagnetic testing techniques for early detection of hydrogen-induced stress corrosion cracking in pipework. Pipe specimens made of steel X20Cr13, which differed in materials state induced by various heat treatments, were exposed to corrosive attack induced in a closed cycle by simultaneous rinsing with NACE solution and stress application through stamp impact. Various micromagnetic testing parameters were measured at the specimens' outside surface during the annealing period. Further, fatigue experiments were made with specimen sets made of steel 1.4541, under various mechanical and temperature stresses (room temperature and 300 C), for measuring the remanent magnetization of the cylindrical fatigue test blocks (equal geometry) cut out of the specimens, in order to conclude information on the martensite content and the fatigue effects. (Orig./CB) [de

  7. Material Induced Anisotropic Damage in DP600

    NARCIS (Netherlands)

    Niazi, Muhammad Sohail; Wisselink, H.H.; Meinders, Vincent T.; van den Boogaard, Antonius H.

    2013-01-01

    Plasticity induced damage development in metals is anisotropic by nature. The anisotropy in damage is driven by two different phenomena; anisotropic deformation state i.e. Load Induced Anisotropic Damage (LIAD) and anisotropic microstructure i.e. Material Induced Anisotropic Damage (MIAD). The

  8. Laser-induced damage in optical materials

    CERN Document Server

    Ristau, Detlev

    2014-01-01

    Dedicated to users and developers of high-powered systems, Laser-Induced Damage in Optical Materials focuses on the research field of laser-induced damage and explores the significant and steady growth of applications for high-power lasers in the academic, industrial, and military arenas. Written by renowned experts in the field, this book concentrates on the major topics of laser-induced damage in optical materials and most specifically addresses research in laser damage that occurs in the bulk and on the surface or the coating of optical components. It considers key issues in the field of hi

  9. Genetic engineering: frost damage trial halted.

    Science.gov (United States)

    Budiansky, S

    The University of California at Berkeley has announced the postponement of a planned experiment involving the field testing of bacteria genetically engineered to reduce frost damage to crops. The action came after Jeremy Rifkin, who had earlier filed suit against the National Institutes of Health after its Recombinant DNA Advisory Committee had approved the experiment, threatened to seek a temporary restraining order against the university to halt the experiment.

  10. Radiation damages in superconducting materials

    International Nuclear Information System (INIS)

    Heinz, W.; Seibt, E.

    1978-01-01

    Radiation damage investigations of technical superconductors are reported and discussed with respect to their main properties like critical current jsub(c), transition temperature Tsub(c), upper critical field Bsub(c2), pinning and annealing behaviour. Ordered A15 type alloys (like Nb 3 Sn and V 3 Ga) show significant reductions of all critical parameters above a threshold of about 2x10 21 m -2 with 50 MeV deuterons corresponding to 2x10 22 neutrons/m 2 (Esub(n)>0.1 MeV). Pure metals and disordered B1 type alloys (like Nb or NbTi) show only a small linear decrease in critical parameters (except Bsub(c2) of niobium). Experimental results are compared with theoretical calculations. (author)

  11. Drilling Damage in Composite Material

    Directory of Open Access Journals (Sweden)

    Luís Miguel P. Durão

    2014-05-01

    Full Text Available The characteristics of carbon fibre reinforced laminates have widened their use from aerospace to domestic appliances, and new possibilities for their usage emerge almost daily. In many of the possible applications, the laminates need to be drilled for assembly purposes. It is known that a drilling process that reduces the drill thrust force can decrease the risk of delamination. In this work, damage assessment methods based on data extracted from radiographic images are compared and correlated with mechanical test results—bearing test and delamination onset test—and analytical models. The results demonstrate the importance of an adequate selection of drilling tools and machining parameters to extend the life cycle of these laminates as a consequence of enhanced reliability.

  12. Failure and damage analysis of advanced materials

    CERN Document Server

    Sadowski, Tomasz

    2015-01-01

    The papers in this volume present basic concepts and new developments in failure and damage analysis with focus on advanced materials such as composites, laminates, sandwiches and foams, and also new metallic materials. Starting from some mathematical foundations (limit surfaces, symmetry considerations, invariants) new experimental results and their analysis are shown. Finally, new concepts for failure prediction and analysis will be introduced and discussed as well as new methods of failure and damage prediction for advanced metallic and non-metallic materials. Based on experimental results the traditional methods will be revised.

  13. Thermal Damage Characterization of Energetic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, P C; DeHaven, M R; Springer, H K; Maienschein, J L

    2009-08-14

    We conducted thermal damage experiments at 180?C on PBXN-9 and characterized its material properties. Volume expansion at high temperatures was very significant which led to a reduction in material density. 2.6% of weight loss was observed, which was higher than other HMX-based formulations. Porosity of PBXN-9 increased to 16% after thermal exposure. Small-scale safety tests (impact, friction, and spark) showed no significant sensitization when the damaged samples were tested at room temperature. Gas permeation measurements showed that gas permeability in damaged materials was several orders of magnitude higher than that in pristine materials. In-situ measurements of gas permeability and density were proved to be possible at higher temperatures.

  14. Genetic Damage Induced by Accidental Environmental Pollutants

    Directory of Open Access Journals (Sweden)

    Beatriz Pérez-Cadahía

    2006-01-01

    Full Text Available Petroleum is one of the main energy sources worldwide. Its transport is performed by big tankers following some established marine routes. In the last 50 years a total amount of 37 oil tankers have given rise to great spills in different parts of the world, Prestige being the last one. After the accident, a big human mobilisation took place in order to clean beaches, rocks and fauna, trying to reduce the environmental consequences of this serious catastrophe. These people were exposed to the complex mixture of compounds contained in the oil. This study aimed at determine the level of environmental exposure to volatile organic compounds (VOC, and the possible damage induced on the population involved in the different cleaning tasks by applying the genotoxicity tests sister chromatid exchanges (SCE, micronucleus (MN test, and comet assay. Four groups of individuals were included: volunteers (V, hired manual workers (MW, hired high-pressure cleaner workers (HPW and controls. The higher VOC levels were associated with V environment, followed by MW and lastly by HPW, probably due to the use of high-pressure cleaners. Oil exposure during the cleaning tasks has caused an increase in the genotoxic damage in individuals, the comet assay being the most sensitive biomarker to detect it. Sex, age and tobacco consumption have shown to influence the level of genetic damage, while the effect of using protective devices was less noticeable than expected, perhaps because the kind used was not the most adequate.

  15. Genetic damage induced by accidental environmental pollutants.

    Science.gov (United States)

    Pérez-Cadahía, Beatriz; Laffon, Blanca; Pásaro, Eduardo; Méndez, Josefina

    2006-09-25

    Petroleum is one of the main energy sources worldwide. Its transport is performed by big tankers following some established marine routes. In the last 50 years a total amount of 37 oil tankers have given rise to great spills in different parts of the world, Prestige being the last one. After the accident, a big human mobilisation took place in order to clean beaches, rocks and fauna, trying to reduce the environmental consequences of this serious catastrophe. These people were exposed to the complex mixture of compounds contained in the oil. This study aimed at determine the level of environmental exposure to volatile organic compounds (VOC), and the possible damage induced on the population involved in the different cleaning tasks by applying the genotoxicity tests sister chromatid exchanges (SCE), micronucleus (MN) test, and comet assay. Four groups of individuals were included: volunteers (V), hired manual workers (MW), hired high-pressure cleaner workers (HPW) and controls. The higher VOC levels were associated with V environment, followed by MW and lastly by HPW, probably due to the use of high-pressure cleaners. Oil exposure during the cleaning tasks has caused an increase in the genotoxic damage in individuals, the comet assay being the most sensitive biomarker to detect it. Sex, age and tobacco consumption have shown to influence the level of genetic damage, while the effect of using protective devices was less noticeable than expected, perhaps because the kind used was not the most adequate.

  16. Radiation damage in barium fluoride detector materials

    International Nuclear Information System (INIS)

    Levey, P.W.; Kierstead, J.A.; Woody, C.L.

    1988-01-01

    To develop radiation hard detectors, particularly for high energy physics studies, radiation damage is being studied in BaF 2 , both undoped and doped with La, Ce, Nd, Eu, Gd and Tm. Some dopants reduce radiation damage. In La doped BaF 2 they reduce the unwanted long lifetime luminescence which interferes with the short-lived fluorescence used to detect particles. Radiation induced coloring is being studied with facilities for making optical measurements before, during and after irradiation with 60 C0 gamma rays. Doses of 10 6 rad, or less, create only ionization induced charge transfer effects since lattice atom displacement damage is negligible at these doses. All crystals studied exhibit color center formation, between approximately 200 and 800 nm, during irradiation and color center decay after irradiation. Thus only measurements made during irradiation show the total absorption present in a radiation field. Both undoped and La doped BaF 2 develop damage at minimum detectable levels in the UV---which is important for particle detectors. For particle detector applications these studies must be extended to high dose irradiations with particles energetic enough to cause lattice atom displacement damage. In principle, the reduction in damage provided by dopants could apply to other applications requiring radiation damage resistant materials

  17. Damage evolution during fatigue in structural materials

    Czech Academy of Sciences Publication Activity Database

    Polák, Jaroslav; Man, Jiří; Petrenec, Martin

    2012-01-01

    Roč. 1, August (2012), s. 3-12 ISSN 2211-8128. [International Congress on Metallurgy and Materials - SAM/CONAMET 2011 /11./. Rosario, 18.10.2011-21.10.2011] R&D Projects: GA ČR GA106/09/1954 Institutional support: RVO:68081723 Keywords : cyclic plasticity * crack nucleation * crack growth * fatigue damage Subject RIV: JL - Materials Fatigue, Friction Mechanics

  18. Radiation damage studies of nuclear structural materials

    International Nuclear Information System (INIS)

    Barat, P.

    2012-01-01

    Maximum utilization of fuel in nuclear reactors is one of the important aspects for operating them economically. The main hindrance to achieve this higher burnups of nuclear fuel for the nuclear reactors is the possibility of the failure of the metallic core components during their operation. Thus, the study of the cause of the possibility of failure of these metallic structural materials of nuclear reactors during full power operation due to radiation damage, suffered inside the reactor core, is an important field of studies bearing the basic to industrial scientific views.The variation of the microstructure of the metallic core components of the nuclear reactors due to radiation damage causes enormous variation in the structure and mechanical properties. A firm understanding of this variation of the mechanical properties with the variation of microstructure will serve as a guide for creating new, more radiation-tolerant materials. In our centre we have irradiated structural materials of Indian nuclear reactors by charged particles from accelerator to generate radiation damage and studied the some aspects of the variation of microstructure by X-ray diffraction studies. Results achieved in this regards, will be presented. (author)

  19. Genetics 101 --The Hereditary Material of Life

    Science.gov (United States)

    ... of this page please turn Javascript on. Feature: Genetics 101 Genetics 101 — The Hereditary Material of Life Past Issues / Summer 2013 Table of Contents Genetics is the study of heredity, the process in ...

  20. Possible genetic damage from diagnostic x irradiation. A review

    International Nuclear Information System (INIS)

    Withrow, T.J.; Andersen, F.A.; Yao, K.T.S.; Stratmeyer, M.E.

    1980-08-01

    Although it is known that x irradiation is capable of producing mutations and chromosomal abnormalities in experimental systems, there is little or no direct evidence of such phenomena in humans. This report reviews some human genetic diseases and chromosomal abnormalities as well as the evidence for x-ray induced mutations and chromosomal abnormalities in experimental systems. The examination of these areas reveals that spontaneous chromosomal abnormalities and genetic diseases are associated with the same type of DNA damage that x irradiation produces in experimental systems. Therefore, it is concluded that genetic radiation damage in humans may mainfest itself as an increase in the spontaneous genetic diseases rather than as any unique disease

  1. Uncertainty on Fatigue Damage Accumulation for Composite Materials

    DEFF Research Database (Denmark)

    Toft, Henrik Stensgaard; Sørensen, John Dalsgaard

    2009-01-01

    In the present paper stochastic models for fatigue damage accumulation for composite materials are presented based on public available constant and variable amplitude fatigue tests. The methods used for estimating the SN-curve and accumulated fatigue damage are presented.......In the present paper stochastic models for fatigue damage accumulation for composite materials are presented based on public available constant and variable amplitude fatigue tests. The methods used for estimating the SN-curve and accumulated fatigue damage are presented....

  2. Metamict state radiation damage in crystalline materials

    International Nuclear Information System (INIS)

    Haaker, R.F.; Ewing, R.C.

    1979-01-01

    Metamict minerals provide an excellent basis for the evaluation of long-term radiation damage effects, particularly such changes in physical and chemical properties as microfracturing, hydrothermal alteration, and solubility. This paper summarizes pertinent literature on metamictization and proposes experiments that are critical to the elucidation of structural controls on radiation damage in crystalline phases

  3. Characteristic of fretting damage in metal material

    Energy Technology Data Exchange (ETDEWEB)

    Li, D.; Zhi, F.

    1988-10-01

    The fretting fatigue experiment of LC4 high strength aluminum alloy is described. An SEM examination of the fractology and morphology of fretting damage is carried out as well as an EDAX analysis of the chemical composition of fretting particles. The results show that many loose oxide particles were produced and accumulated in the fretting damage region. 10 references.

  4. Damage and failure processes in structural materials

    International Nuclear Information System (INIS)

    Embury, J.D.

    1993-01-01

    At large plastic strains consideration must be given not only to the descriptions of work hardening and texture evolution but also to the process of damage accumulation and the documentation of the various modes of failure which may terminate the plastic history. In this presentation consideration is given first to documenting the various modes of failure and their dependence on stress state. It is then shown that damage accumulation can be studied in a quantitative manner by using model systems in conjunction with FEM calculations. Finally consideration is given to complex forming processes such as ironing to show how studies of damage initiation and accumulation relate to practical engineering problems. (orig.)

  5. Magnetic resonance imaging (MRI): A review of genetic damage investigations.

    Science.gov (United States)

    Vijayalaxmi; Fatahi, Mahsa; Speck, Oliver

    2015-01-01

    Magnetic resonance imaging (MRI) is a powerful, non-invasive diagnostic medical imaging technique widely used to acquire detailed information about anatomy and function of different organs in the body, in both health and disease. It utilizes electromagnetic fields of three different frequency bands: static magnetic field (SMF), time-varying gradient magnetic fields (GMF) in the kHz range and pulsed radiofrequency fields (RF) in the MHz range. There have been some investigations examining the extent of genetic damage following exposure of bacterial and human cells to all three frequency bands of electromagnetic fields, as used during MRI: the rationale for these studies is the well documented evidence of positive correlation between significantly increased genetic damage and carcinogenesis. Overall, the published data were not sufficiently informative and useful because of the small sample size, inappropriate comparison of experimental groups, etc. Besides, when an increased damage was observed in MRI-exposed cells, the fate of such lesions was not further explored from multiple 'down-stream' events. This review provides: (i) information on the basic principles used in MRI technology, (ii) detailed experimental protocols, results and critical comments on the genetic damage investigations thus far conducted using MRI equipment and, (iii) a discussion on several gaps in knowledge in the current scientific literature on MRI. Comprehensive, international, multi-centered collaborative studies, using a common and widely used MRI exposure protocol (cardiac or brain scan) incorporating several genetic/epigenetic damage end-points as well as epidemiological investigations, in large number of individuals/patients are warranted to reduce and perhaps, eliminate uncertainties raised in genetic damage investigations in cells exposed in vitro and in vivo to MRI. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Dissection of DNA damage responses using multiconditional genetic interaction maps

    NARCIS (Netherlands)

    Guénolé, Aude

    2013-01-01

    To protect the genome, cells have evolved a diverse set of pathways designed to sense, signal, and repair multiple types of DNA damage. To assess the degree of coordination and crosstalk among these pathways, we systematically mapped changes in the cell's genetic network across a panel of different

  7. Preventing organ damage by genetic testing for hereditary ...

    African Journals Online (AJOL)

    Haemochromatosis can be prevented by regular blood donation or phlebotomy and therefore detection of a genetic predisposition at an early age, before irreversible damage to cardiac, hepatic and endocrine tissue occurs, represents an important clinical goal. South African Family Practice Vol. 47(2) 2005: 44-45 ...

  8. Laser Induced Damage in Optical Materials: 1979.

    Science.gov (United States)

    1980-07-01

    MgO, HfO2 , ZrO2 , Nd203, CeO2 , TiO 2 and SiO 2 films about 5000 R thick, deposited on Suprasil I substrates. They also compared the damage threshold...ion filtered and reactive gas treated for purification prior to crystal growth. The samples were surface ground, polished with a slurry of Linde A in...A1203, BeO, MgO, HfO 2 , ZrO2, Nd203, CeO2 , TiO2 and Si02- thickness about O.5/um - were electron gun evaporated Zn Suprasil I substrates. Damage

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

    Science.gov (United States)

    Glass, A J; Guenther, A H

    1976-06-01

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

  10. SPECTER: neutron damage calculations for materials irradiations

    International Nuclear Information System (INIS)

    Greenwood, L.R.; Smither, R.K.

    1985-01-01

    Neutron displacement damage-energy cross sections have been calculated for 41 isotopes in the energy range from 10 -10 to 20 MeV. Calculations were performed on a 100-point energy grid using nuclear cross sections from ENDF/B-V and the DISCS computer code. Elastic scattering is treated exactly including angular distributions from ENDF/B-V. Inelastic scattering calculations consider both discrete and continuous nuclear level distributions. Multiple (n,xn) reactions use a Monte Carlo technique to derive the recoil distributions. The (n,d) and (n,t) reactions are treated as (n,p) and (n, 3 He) as (n, 4 He). The (n,γ) reaction and subsequent β-decay are also included, using a new treatment of γ-γ coincidences, angular correlations, β-neutrino correlations, and the incident neutron energy. The Lindhard model was used to compute the energy available for nuclear displacement at each recoil energy. The SPECTER computer code has been developed to simplify damage calculations. The user need only specify a neutron energy spectrum. SPECTER will then calculate spectral-averaged displacements, recoil spectra, gas production, and total damage energy (Kerma). The SPECTER computer code package is readily accessible to the fusion community via the National Magnetic Fusion Energy Computer Center (NMFECC) at Lawrence Livermore National laboratory

  11. Manipulating Genetic Material in Bacteria

    Science.gov (United States)

    1998-01-01

    Lisa Crawford, a graduate research assistant from the University of Toledo, works with Laurel Karr of Marshall Space Flight Center (MSFC) in the molecular biology laboratory. They are donducting genetic manipulation of bacteria and yeast for the production of large amount of desired protein. Photo credit: NASA/Marshall Space Flight Center (MSFC)

  12. Radiation damage of organic composite material for fusion magnet

    International Nuclear Information System (INIS)

    Nishijima, S.; Okada, T.

    1991-01-01

    Fusion superconducting magnets are 'series machines' in the sense that the complete magnet may decrease in overall performance when even one component does not deliver the expected performance. Such magnets are often operated under severe conditions, such as radiation environments and those materials which are most prone to damage under such radiation environments demand particular attention. The component most sensitive to radiation damage in the fusion magnet is the organic composite material used for insulation, usually glass fibre reinforced plastic (GFRP). Radiation resistant GFRPs have been developed and these will be discussed in this work, together with other aspects of radiation damage of organic composite materials. (author)

  13. An anisotropic tertiary creep damage constitutive model for anisotropic materials

    International Nuclear Information System (INIS)

    Stewart, Calvin M.; Gordon, Ali P.; Ma, Young Wha; Neu, Richard W.

    2011-01-01

    When an anisotropic material is subject to creep conditions and a complex state of stress, an anisotropic creep damage behavior is observed. Previous research has focused on the anisotropic creep damage behavior of isotropic materials but few constitutive models have been developed for anisotropic creeping solids. This paper describes the development of a new anisotropic tertiary creep damage constitutive model for anisotropic materials. An advanced tensorial damage formulation is implemented which includes both material orientation relative to loading and the degree of creep damage anisotropy in the model. A variation of the Norton-power law for secondary creep is implemented which includes the Hill's anisotropic analogy. Experiments are conducted on the directionally-solidified bucket material DS GTD-111. The constitutive model is implemented in a user programmable feature (UPF) in ANSYS FEA software. The ability of the constitutive model to regress to the Kachanov-Rabotnov isotropic tertiary creep damage model is demonstrated through comparison with uniaxial experiments. A parametric study of both material orientation and stress rotation are conducted. Results indicate that creep deformation is modeled accurately; however an improved damage evolution law may be necessary. - Highlights: → The deformation of anisotropic creeping solid is directionally dependent. → Few constitutive models have been developed to deal with anisotropic behavior. → A transversely-isotropic nickel base superalloy, DS GTD-111, is studied. → A vector constitutive model based on the Kachanov-Rabotnov formulation is developed. → The new model accurately models deformation at various orientations.

  14. Physics of radiation damage and radiation materials technology

    International Nuclear Information System (INIS)

    1992-01-01

    This issue of 'Problems in Atomic Science and Technology', on the 'Physics of Radiation Damage and Radiation Materials Technology', is a collection of 24 papers on the effects on or processes in materials due to their irradiation by neutrons, ions in the energy range from a few tens of keV to several MeV (deuterium, helium, oxygen), and electrons. Included are studies on radiation damage of materials, on ion implantation, thermonuclear reactor materials testing, fast-particle energy loss ramifications for fusion reaction rates in materials, and biological radiation effects

  15. Precursor to damage state quantification in composite materials (Conference Presentation)

    Science.gov (United States)

    Patra, Subir; Banerjee, Sourav

    2017-04-01

    Nonlinear damage in the composite materials is developed with the growth of damages in the material under fatigue loading. Nonlinear ultrasonic techniques are sensitive to early stage damages such as, fiber breakages, matrix micro-cracking, and deboning etc. Here, in this work, early stage damages are detected in Unidirectional (UD) carbon fiber composite under fatigue loading. Specimens are prepared according to American Society for Testing and Materials (ASTM) standard. Specimens are subjected to low cycle high load (LCHL) fatigue loading until 150,000 cycles. Sensors are mounted on the specimen used for actuation and sensing. A five count tone burst with low frequency (fc =375 kHz) followed by high frequency (fc =770 kHz) signal, was used as actuation signal. Pitch-catch experiments are collected at the interval of 5,000 cycles. Sensor signals are collected for various excitation voltage (from 5V to 20V, with 5V interval). First Fourier Transform (FFT) of the sensor signals are performed and side band frequencies are observed at around 770 kHz. Severity of damages in the material is quantified from the ratio of amplitude of side band frequencies with the central frequency. Nonlinearity in the material due to damage development is also investigated from the damage growth curve obtained at various excitation amplitude. Optical Microcopy imaging were also performed at the interval of 5,000 to examine developments of damages inside the material. This study has a good potential in detection of early stage damages in composite materials.

  16. Minimizing material damage using low temperature irradiation

    Science.gov (United States)

    Craven, E.; Hasanain, F.; Winters, M.

    2012-08-01

    Scientific advancements in healthcare driven both by technological breakthroughs and an aging and increasingly obese population have lead to a changing medical device market. Complex products and devices are being developed to meet the demands of leading edge medical procedures. Specialized materials in these medical devices, including pharmaceuticals and biologics as well as exotic polymers present a challenge for radiation sterilization as many of these components cannot withstand conventional irradiation methods. The irradiation of materials at dry ice temperatures has emerged as a technique that can be used to decrease the radiation sensitivity of materials. The purpose of this study is to examine the effect of low temperature irradiation on a variety of polymer materials, and over a range of temperatures from 0 °C down to -80 °C. The effectiveness of microbial kill is also investigated under each of these conditions. The results of the study show that the effect of low temperature irradiation is material dependent and can alter the balance between crosslinking and chain scission of the polymer. Low temperatures also increase the dose required to achieve an equivalent microbiological kill, therefore dose setting exercises must be performed under the environmental conditions of use.

  17. A nonlinear CDM based damage growth law for ductile materials

    Science.gov (United States)

    Gautam, Abhinav; Priya Ajit, K.; Sarkar, Prabir Kumar

    2018-02-01

    A nonlinear ductile damage growth criterion is proposed based on continuum damage mechanics (CDM) approach. The model is derived in the framework of thermodynamically consistent CDM assuming damage to be isotropic. In this study, the damage dissipation potential is also derived to be a function of varying strain hardening exponent in addition to damage strain energy release rate density. Uniaxial tensile tests and load-unload-cyclic tensile tests for AISI 1020 steel, AISI 1030 steel and Al 2024 aluminum alloy are considered for the determination of their respective damage variable D and other parameters required for the model(s). The experimental results are very closely predicted, with a deviation of 0%-3%, by the proposed model for each of the materials. The model is also tested with predictabilities of damage growth by other models in the literature. Present model detects the state of damage quantitatively at any level of plastic strain and uses simpler material tests to find the parameters of the model. So, it should be useful in metal forming industries to assess the damage growth for the desired deformation level a priori. The superiority of the new model is clarified by the deviations in the predictability of test results by other models.

  18. Request from radiation damage evaluation in materials

    International Nuclear Information System (INIS)

    Fukuya, Koji; Kimura, Itsuro

    2003-01-01

    Radiation transport calculations in a PWR using cross-section data sets based on JENDL3.2 showed that the calculated neutron fluence agreed well with the dosimeter measurements and that the fast neutron flux and dpa rate differed within 10% from to those calculated using ENDF/B-IV and ENDF/B-VI based data sets. Calculations of helium generation in structural materials in the PWR using ENDF/B-VI showed that the dominant source of helium is the (n, α) reaction of 59 Ni and that the calculated helium content agreed with the measurements. For accurate estimation of radiation field from a material viewpoint, it is desirable to construct proper cross-section libraries, which have a proper energy group structure and contain sufficient elements including 59 Ni as an indispensable element. (author)

  19. Protective effects of vitamin C against gamma-ray induced wholly damage and genetic damage

    International Nuclear Information System (INIS)

    Fu Chunling; Jiang Weiwei; Zhang Ping; Chen Xiang; Zhu Shengtao

    2000-01-01

    Objective: Protective effects of supplemental vitamin C against 60 Co-gamma-ray induced wholly damage and genetic damage was investigated in mice. Method: Mice were divided into normal control group, irradiation control group and vitamin C experimental group 1,2,3 (which were orally given vitamin C 15, 30, 45 mg/kg.bw for 10 successive days respectively prior to gamma-ray irradiation). Micronuclei in the bone marrow polychromatophilic erythrocytes in each group of mice were examined and the 30 day survival rate of mice following whole-body 5.0 Gy γ irradiation were also determined. Results: Supplemental vitamin C prior to gamma-rays irradiation can significantly decrease bone marrow PECMN rate of mice and increase 30 day survival rate and prolong average survival time. The protection factor is 2.09. Conclusion: Vitamin C has potent protective effects against gamma irradiation induced damage in mice. In certain dose range, vitamin C can absolutely suppress the gamma-rays induced genetic damage in vivo

  20. Examination of material damage on components of future fusion reactors

    International Nuclear Information System (INIS)

    Gutzeit, V.; Hoven, H.; Linke, J.; Roedig, M.

    1998-01-01

    Nowadays materials based on beryllium, carbon or tungsten are those most favored for use as wall components which will be heat loaded by the plasma in future fusion reactors. These materials are subjected to extreme heat loads (up to 20 MWm -2 ) during normal operation. In order to carry the heat away safely, the above materials are joined to metallic heat sinks (molybdenum or copper alloys) by an appropriate joining technique. As the components and the joints are thermally cycled by the heat load, thermal fatigue will cause material damage. Additionally, in the case of an unsteady plasma the materials will be extremely thermoshocked by energy densities up to 140 MJm -2 . Under these conditions the materials facing the plasma (Be, C, W) will be strongly eroded. At the same time local melting, recrystallisation and cracking will cause extensive material damage. The thermal load on materials normally observed in fusion reactors will be simulated by means of appropriate testing equipment (electron-beam for instance). The material damage thus caused will be examined by metallography, scanning electron microscopy using energy dispersive analysis, quantitative microstructure analysis and non-contact profilometry. Based on these results appropriate materials as well as joining techniques will be designed for use in future fusion facilities such as ITER. (orig.) [de

  1. Mesoscopic analysis of drying shrinkage damage in a cementitious material

    DEFF Research Database (Denmark)

    Moonen, P.; Pedersen, R.R.; Simone, A.

    2008-01-01

    Concrete and cement-based materials exhibit shrinkage when exposed to drying. Structural effects and inhomogeneity of material properties adverse free shrinkage, hereby inducing stress concentrations and possibly damage. In this contribution, the magnitude of shrinkage- induced damage during...... a typical sample preparation procedure is assessed. To this extent, a coupled hygro-thermo-mechanical model, incorporating rate-effects, is developed. The constitutive model is applied at a mesoscopic level where the aggregates and the interfacial transition zone (ITZ) are explicitly modelled. Two drying...... temperatures are considered: 35 °C and 50 °C. Significantly more micro-damage and higher internal stresses are found for the latter, revealing the importance of drying shrinkage damage, even at laboratory scale....

  2. Calculations on neutron irradiation damage in reactor materials

    International Nuclear Information System (INIS)

    Sone, Kazuho; Shiraishi, Kensuke

    1976-01-01

    Neutron irradiation damage calculations were made for Mo, Nb, V, Fe, Ni and Cr. Firstly, damage functions were calculated as a function of neutron energy with neutron cross sections of elastic and inelastic scatterings, and (n,2n) and (n,γ) reactions filed in ENDF/B-III. Secondly, displacement damage expressed in displacements per atom (DPA) was estimated for neutron environments such as fission spectrum, thermal neutron reactor (JMTR), fast breeder reactor (MONJU) and two fusion reactors (The Conceptual Design of Fusion Reactor in JAERI and ORNL-Benchmark). then, damage cross section in units of dpa. barn was defined as a factor to convert a given neutron fluence to the DPA value, and was calculated for the materials in the above neutron environments. Finally, production rates of helium and hydrogen atoms were calculated with (n,α) and (n,p) cross sections in ENDF/B-III for the materials irradiated in the above reactors. (auth.)

  3. Identification Damage Model for Thermomechanical Degradation of Ductile Heterogeneous Materials

    Science.gov (United States)

    Amri, A. El; Yakhloufi, M. H. El; Khamlichi, A.

    2017-05-01

    The failure of ductile materials subject to high thermal and mechanical loading rates is notably affected by material inertia. The mechanisms of fatigue-crack propagation are examined with particular emphasis on the similarities and differences between cyclic crack growth in ductile materials, such as metals, and corresponding behavior in brittle materials, such as intermetallic and ceramics. Numerical simulations of crack propagation in a cylindrical specimen demonstrate that the proposed method provides an effective means to simulate ductile fracture in large scale cylindrical structures with engineering accuracy. The influence of damage on the intensity of the destruction of materials is studied as well.

  4. Fundamental Technology Development for Radiation Damage in Nuclear Materials

    International Nuclear Information System (INIS)

    Kwon, Sang Chul; Kwon, J. H.; Kim, E. S. and others

    2005-04-01

    This project was performed to achieve technologies for the evaluation of radiation effects at materials irradiated at HANARO and nuclear power plants, to establish measurement equipment and software for the analysis of radiation defects and to set up facilities for the measurements of radiation damage with non-destructive methods. Major targets were 1) establishment of hot laboratories and remote handling facilities/ technologies for the radioactive material tests, 2) irradiation test for the simulation of nuclear power plant environment and measurement/calculation of physical radiation damage, 3) evaluation and analysis of nano-scale radiation damage, 4) evaluation of radiation embrittlement with ultrasonic resonance spectrum measurement and electromagnetic measurement and 5) basic research of radiation embrittlement and radiation damage mechanism. Through the performance of 3 years, preliminary basics were established for the application research to evaluation of irradiated materials of present nuclear power plants and GEN-IV systems. Particularly the results of SANS, PAS and TEM analyses were the first output in Korea. And computer simulations of radiation damage were tried for the first time in Korea. The technologies will be developed for the design of GEN-IV material

  5. Photoinduced processes, radiation interaction with material and damages - material hardness

    Directory of Open Access Journals (Sweden)

    Srećković Milesa Ž.

    2015-01-01

    Full Text Available Photo and nuclear radiation induced processes are considered through the interaction of radiation with semiconducting, metallic and other materials, including the scintillator materials. The improvement of component efficiency by the use of quantum generators, trimming and hybrid processes with nuclear radiation has been analyzed. The studied processes can be positive or negative depending on application. Besides the experimental approach to the processes and chosen interactions, the analytical description of our experiments, as well as ones from other references, has been performed. The contemporary couplings between the nuclear physics, laser techniques and respective dosimetric aspects have been considered. [Projekat Ministarstva nauke Republike Srbije, br. II45003 i br. TP 35046

  6. Nuclear data for radiation damage estimates for reactor structural materials

    International Nuclear Information System (INIS)

    Piksaikin, V.

    1986-06-01

    The IAEA Consultants' Meeting on Nuclear Data for Radiation Damage Estimates for Reactor Structural Materials was convened by the IAEA Nuclear Data Section in Santa Fe, New Mexico, USA from 20-22 May 1985. The meeting was attended by 17 participants from 10 countries and 2 international organizations. The main objectives of the meeting were to review the status of displacement cross sections and the requirements for nuclear data needed for radiation damage estimates in reactor structural materials, and to develop recommendations for future activities in this field. This publication contains the text of all the papers prepared especially for this meeting including the conclusions and recommendations worked out during the meeting

  7. Biomarkers of genetic damage in human populations exposed to pesticides

    International Nuclear Information System (INIS)

    Aiassa, Delia; Manas, Fernando; Bosch, Beatriz; Gentile, Natalia; Bernardi, Natali; Gorla, Nora

    2012-01-01

    The effect of pesticides on human, animal and environmental health has been cause of concern in the scientific community for a long time. Numerous studies have reported that pesticides are not harmless and that their use can lead to harmful biological effects in the medium and long term, in exposed human and animals, and their offspring. The importance of early detection of genetic damage is that it allows us to take the necessary measures to reduce or eliminate the exposure to the deleterious agent when damage is still reversible, and thus to prevent and to diminish the risk of developing tumors or other alterations. In this paper we reviewed the main concepts in the field, the usefulness of genotoxicity studies and we compiled studies performed during the last twenty years on genetic monitoring of people occupationally exposed to pesticides. we think that genotoxicity tests, including that include chromosomal aberrations, micronucleus, sister chromatid exchanges and comet assays, should be considered as essential tools in the implementation of complete medical supervision for people exposed to potential environmental pollutants, particularly for those living in the same place as others who were others have already developed some type of malignancy. This action is particularly important at early stages to prevent the occurrence of tumors, especially from environmental origins.

  8. Radiation Damage in Reactor Materials. Part of the Proceedings of the Symposium on Radiation Damage in Solids and Reactor Materials

    International Nuclear Information System (INIS)

    1963-01-01

    Radiation damage has presented a new design parameter for the selection of materials to be used in fuel and cladding elements, moderators, structural components and pressure vessels in nuclear reactors. The severe and novel requirements for certain optimum combinations of physical and nuclear properties have emphasized the need for a better understanding of the basic mechanisms of radiation damage. This knowledge is not only essential for progress in the field of nuclear energy, but has direct applications to space technology and semi-conductor research as well. The IAEA, as part of its programme of promoting nuclear technology, therefore convened the Symposium on Radiation Damage in Solids and Reactor Materials, 7-11 May 1962. At the invitation of, and with generous material assistance from, the Government of Italy, the Symposium was held at Venice. The Symposium was primarily concerned with the investigation of the fundamental processes of radiation that underlie the behaviour of metals, alloys and ceramics that are actually useful or potentially useful reactor materials. Two sessions were devoted to studies of irradiation effects on simple metals, as these effects are easiest to interpret. Other topics included general theory, alloys, fissionable and moderator materials and special experimental techniques for radiation damage studies. The properties influenced by irradiation which were of main concern were those of primary importance to the behaviour of solids as reactor materials (e. g. dimensional stability, phase transformation, radiation hardening, fracture, fission-gas escape from uranium and its compounds). Other properties, such as optical, electrical and magnetic properties, and effects on semiconductors, ionic and other non-metallic crystals are also of interest in that these studies can increase our knowledge of the mechanism of radiation damage in solids and provide a tool for investigation into the physics of the solid state by offering a means of

  9. Heavy ion linear accelerator for radiation damage studies of materials

    Energy Technology Data Exchange (ETDEWEB)

    Kutsaev, Sergey V.; Mustapha, Brahim; Ostroumov, Peter N.; Nolen, Jerry; Barcikowski, Albert; Pellin, Michael; Yacout, Abdellatif

    2017-03-01

    A new eXtreme MATerial (XMAT) research facility is being proposed at Argonne National Laboratory to enable rapid in situ mesoscale bulk analysis of ion radiation damage in advanced materials and nuclear fuels. This facility combines a new heavy-ion accelerator with the existing high-energy X-ray analysis capability of the Argonne Advanced Photon Source. The heavy-ion accelerator and target complex will enable experimenters to emulate the environment of a nuclear reactor making possible the study of fission fragment damage in materials. Material scientists will be able to use the measured material parameters to validate computer simulation codes and extrapolate the response of the material in a nuclear reactor environment. Utilizing a new heavy-ion accelerator will provide the appropriate energies and intensities to study these effects with beam intensities which allow experiments to run over hours or days instead of years. The XMAT facility will use a CW heavy-ion accelerator capable of providing beams of any stable isotope with adjustable energy up to 1.2 MeV/u for U-238(50+) and 1.7 MeV for protons. This energy is crucial to the design since it well mimics fission fragments that provide the major portion of the damage in nuclear fuels. The energy also allows damage to be created far from the surface of the material allowing bulk radiation damage effects to be investigated. The XMAT ion linac includes an electron cyclotron resonance ion source, a normal-conducting radio-frequency quadrupole and four normal-conducting multi-gap quarter-wave resonators operating at 60.625 MHz. This paper presents the 3D multi-physics design and analysis of the accelerating structures and beam dynamics studies of the linac.

  10. Radiation damage with biological specimens and organic materials

    International Nuclear Information System (INIS)

    Glaeser, R.M.

    1979-01-01

    The radiation damage referred to in this chapter is defined as any changes in the physical structure or chemical makeup of the specimen which occur as a result of exposure to the electron beam. Radiation damage occurs in organic materials predominantly as a consequence of inelastic scattering of the incident electrons which frequently results in molecular ionization and radiolysis. Other types of radiation damage which can occur are specimen etching, which occurs as the result of synergistic action of electron irradiation and the presence of certain residual gasses, and specimen heating which occurs only at electron current densities that are large on the scale of ionization damage. The primary events in radiation physics and radiation chemistry and signal-to-noise considerations are also discussed in some detail

  11. Mechanical Behaviour of Materials Volume II Fracture Mechanics and Damage

    CERN Document Server

    François, Dominique; Zaoui, André

    2013-01-01

    Designing new structural materials, extending lifetimes and guarding against fracture in service are among the preoccupations of engineers, and to deal with these they need to have command of the mechanics of material behaviour. This ought to reflect in the training of students. In this respect, the first volume of this work deals with elastic, elastoplastic, elastoviscoplastic and viscoelastic behaviours; this second volume continues with fracture mechanics and damage, and with contact mechanics, friction and wear. As in Volume I, the treatment links the active mechanisms on the microscopic scale and the laws of macroscopic behaviour. Chapter I is an introduction to the various damage phenomena. Chapter II gives the essential of fracture mechanics. Chapter III is devoted to brittle fracture, chapter IV to ductile fracture and chapter V to the brittle-ductile transition. Chapter VI is a survey of fatigue damage. Chapter VII is devoted to hydogen embrittlement and to environment assisted cracking, chapter VIII...

  12. Associations between Fungal Species and Water-Damaged Building Materials

    DEFF Research Database (Denmark)

    Andersen, Birgitte; Frisvad, Jens Christian; Søndergaard, Ib

    2011-01-01

    Fungal growth in damp or water-damaged buildings worldwide is an increasing problem, which has adverse effects on both the occupants and the buildings. Air sampling alone in moldy buildings does not reveal the full diversity of fungal species growing on building materials. One aim of this study...

  13. Transport properties of damaged materials. Cementitious barriers partnership

    Energy Technology Data Exchange (ETDEWEB)

    Langton, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2014-11-01

    The objective of the Cementitious Barriers Partnership (CBP) project is to develop tools to improve understanding and prediction of the long-term structural, hydraulic, and chemical performance of cementitious barriers used in low-level waste storage applications. One key concern for the long-term durability of concrete is the degradation of the cementitious matrix, which occurs as a result of aggressive chemical species entering the material or leaching out in the environment, depending on the exposure conditions. The objective of the experimental study described in this report is to provide experimental data relating damage in cementitious materials to changes in transport properties, which can eventually be used to support predictive model development. In order to get results within a reasonable timeframe and to induce as much as possible uniform damage level in materials, concrete samples were exposed to freezing and thawing (F/T) cycles. The methodology consisted in exposing samples to F/T cycles and monitoring damage level with ultrasonic pulse velocity measurements. Upon reaching pre-selected damage levels, samples were tested to evaluate changes in transport properties. Material selection for the study was motivated by the need to get results rapidly, in order to assess the relevance of the methodology. Consequently, samples already available at SIMCO from past studies were used. They consisted in three different concrete mixtures cured for five years in wet conditions. The mixtures had water-to-cement ratios of 0.5, 0.65 and 0.75 and were prepared with ASTM Type I cement only. The results showed that porosity is not a good indicator for damage caused by the formation of microcracks. Some materials exhibited little variations in porosity even for high damage levels. On the other hand, significant variations in tortuosity were measured in all materials. This implies that damage caused by internal pressure does not necessarily create additional pore space in

  14. Transport properties of damaged materials. Cementitious barriers partnership

    International Nuclear Information System (INIS)

    Langton, C.

    2014-01-01

    The objective of the Cementitious Barriers Partnership (CBP) project is to develop tools to improve understanding and prediction of the long-term structural, hydraulic, and chemical performance of cementitious barriers used in low-level waste storage applications. One key concern for the long-term durability of concrete is the degradation of the cementitious matrix, which occurs as a result of aggressive chemical species entering the material or leaching out in the environment, depending on the exposure conditions. The objective of the experimental study described in this report is to provide experimental data relating damage in cementitious materials to changes in transport properties, which can eventually be used to support predictive model development. In order to get results within a reasonable timeframe and to induce as much as possible uniform damage level in materials, concrete samples were exposed to freezing and thawing (F/T) cycles. The methodology consisted in exposing samples to F/T cycles and monitoring damage level with ultrasonic pulse velocity measurements. Upon reaching pre-selected damage levels, samples were tested to evaluate changes in transport properties. Material selection for the study was motivated by the need to get results rapidly, in order to assess the relevance of the methodology. Consequently, samples already available at SIMCO from past studies were used. They consisted in three different concrete mixtures cured for five years in wet conditions. The mixtures had water-to-cement ratios of 0.5, 0.65 and 0.75 and were prepared with ASTM Type I cement only. The results showed that porosity is not a good indicator for damage caused by the formation of microcracks. Some materials exhibited little variations in porosity even for high damage levels. On the other hand, significant variations in tortuosity were measured in all materials. This implies that damage caused by internal pressure does not necessarily create additional pore space in

  15. Monitoring genetic damage to ecosystems from hazardous waste

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, S.L.

    1992-03-01

    Applications of ecological toxicity testing to hazardous waste management have increased dramatically over the last few years, resulting in a greater awareness of the need for improved biomonitoring techniques. Our laboratory is developing advanced techniques to assess the genotoxic effects of environmental contamination on ecosystems. We have developed a novel mutagenesis assay using the nematode Caenorhabditis elegans, which is potentially applicable for multimedia studies in soil, sediment, and water. In addition, we are conducting validation studies of a previously developed anaphase aberration test that utilizes sea urchin embryos. Other related efforts include field validation studies of the new tests, evaluation of their potential ecological relevance, and analysis of their sensitivity relative to that of existing toxicity tests that assess only lethal effects, rather than genetic damage.

  16. Dynamic damage nucleation and evolution in multiphase materials

    Science.gov (United States)

    Fensin, S. J.; Escobedo, J. P.; Gray, G. T.; Patterson, B. M.; Trujillo, C. P.; Cerreta, E. K.

    2014-05-01

    For ductile metals, dynamic fracture occurs through void nucleation, growth, and coalescence. Previous experimental works in high purity metals have shown that microstructural features such as grain boundaries, inclusions, vacancies, and heterogeneities can act as initial void nucleation sites. However, for materials of engineering significance, those with, second phase particles it is less clear what the role of a soft second phase will be on damage nucleation and evolution. To approach this problem in a systematic manner, two materials have been investigated: high purity copper and copper with 1% lead. These materials have been shock loaded at ˜1.5 GPa and soft recovered. In-situ free surface velocity information and post mortem metallography reveals the presence of a high number of small voids in CuPb in comparison to a lower number of large voids in Cu. This suggests that damage evolution is nucleation dominated in the CuPb and growth dominated in the pure Cu.

  17. Thermal Damage Detection and Characterization in Porous Materials

    Science.gov (United States)

    2011-11-30

    Thermal Damage Detection and Characterization in Porous Materials H.T. Banks ∗ and Amanda Keck Criner† Center for Research in Scientific Computation...methods described in [3], which are denoted Ωi with boundaries ∂Ωi for i = 1, 2 . . . nr. The undamaged perforated domain Ω is given by Ω̂ \\ (∪ nri =1Ωi... Banks , Brittany Boudreaux, Amanda Keck Criner, Krista Foster, Cerena Uttal, Thomas Vogel, and William P. Winfree, Thermal based damage detection in porous

  18. Characterization of the damage produced on different materials surfaces

    International Nuclear Information System (INIS)

    Dellavale Clara, Hector Damian

    2004-01-01

    In the present work the characterization techniques of surfaces ULOI and RIMAPS have been applied on laboratory samples made from aluminium, stainless steel and material based on fiberglass.The resultant surfaces of, chemical etching with corrosive agents Keller and Tucker, mechanic damage from the wear and tear of abrasive paper and sandrubbing with alumina particles, are analyzed to different level of damage.The systematic application of the above mentioned techniques is carried out with the objective of finding information, which allows to characterize the superficial damage, both in its incipient state as in the extreme situation revealed by the presence of etch pits. Important results have been obtained, in the characterization of the incipient stage of the chemical etching, using the curves of the normalized area.In addition, it was possible to verify the capacity of the techniques in the early detection of the preferential directions generated by the etch pits

  19. Damage by radiation in structural materials of BWR reactor vessels

    International Nuclear Information System (INIS)

    Robles, E.; Balcazar, M.; Alpizar, A.M.; Calderon, B.E.

    2002-01-01

    The structural materials which are manufactured the pressure vessels of the BWR reactors undergo degradation in their mechanical properties mainly due to the damage produced by the fast neutrons (E> 1 MeV) coming from the reactor core. The mechanisms of neutron damage in this type of materials are experimentally studied, through the irradiation of vessel steel in experimental reactors for a quickly ageing. Alternately the neutron damage through steel irradiation with heavy ions is simulated. In this work the first results of the damage induced by irradiation of a similar steel to the vessel of a BWR reactor are shown. The irradiation was performed with fast neutrons (E> 1 MeV, fluence of 1.45 x 10 18 n/cm 2 ) in the TRIGA Mark III Salazar reactor and separately with Ni +3 ions in a Tandetrom accelerator (E= 4.8 MeV and an ion flux rank of 0.1 to 53 ions/A 2 ). (Author)

  20. Fast Neutron Damage Studies on NdFeB Materials

    CERN Document Server

    Spencer, James; Baldwin, A; Boussoufi, Moe; Pellet, David; Volk, James T; Wolf, Zachary

    2005-01-01

    Many materials and electronics need to be tested for the radiation environment expected at linear colliders (LC) where the accelerator and detectors will be subjected to large fluences of hadrons, leptons and gammas over the life of the facility. Although the linacs will be superconducting, there are still many potential uses for NdFeB in the damping rings, injection and extraction lines and final focus. Our understanding of the radiation damage situation for rare earth permanent magnet materials was presented at PAC2003 and our first measurements of fast neutron, stepped doses at the UC Davis McClellan Nuclear Reactor Center (UCD MNRC) were presented at EPAC2004 where the damage appeared proportional to the distances between the effective operating points and Hc. Here we have extended those doses and included more commercial samples together with the induced radioactivities associated with their respective dopants. Hall probe data for the external induction distributions are compared with vector magnetizatio...

  1. Assessment of the material properties of a fire damaged building

    OpenAIRE

    Oladipupo OLOMO; Olufikayo ADERINLEWO; Moses TANIMOLA; Silvana CROOPE

    2012-01-01

    This study identifies a process for assessing the material properties of a fire damaged building so as to determine whether the remains can be utilized in construction or be demolished. Physical and chemical analysis were carried out on concrete and steel samples taken from various elements of the building after thorough visual inspection of the entire building had been conducted. The physical (non-destructive) tests included the Schmidt hammer and ultrasonic pulse velocity tests on the concr...

  2. Compilation of radiation damage test data cable insulating materials

    CERN Document Server

    Schönbacher, H; CERN. Geneva

    1979-01-01

    This report summarizes radiation damage test data on commercially available organic cable insulation and jacket materials: ethylene- propylene rubber, Hypalon, neoprene rubber, polyethylene, polyurethane, polyvinylchloride, silicone rubber, etc. The materials have been irradiated in a nuclear reactor to integrated absorbed doses from 5*10/sup 5/ to 5*10/sup 6/ Gy. Mechanical properties, e.g. tensile strength, elongation at break, and hardness, have been tested on irradiated and non-irradiated samples. The results are presented in the form of tables and graphs, to show the effect of the absorbed dose on the measured properties. (13 refs).

  3. Particle radiation-induced genetic damage in vivo

    International Nuclear Information System (INIS)

    Chang, P.Y.; Bakke, J.; Lin, S.

    2003-01-01

    Full text: Assessment of radiation-induced alterations in the genomic is important to determine both short and long-term effects after exposure. Transgenic mouse mutation model systems, based on the insertion of specific target genes into the genome of every cell of the animals, provide a rapid and efficient means to obtain statistically reliable results on the frequencies of mutations in all tissues without requiring prior drug selection and clonal expansion of the target cells. We are using the plasmid-based lacZ transgenic mouse model system to measure the dose- and temporal-dependent particle-radiation induced responses. We measured cytogenetic damage to the hematopoietic system as well as mutations in the transgene in both the brain and spleen tissues after an acute dose of 250 MeV/amu protons or 1 GeV/amu iron ions. The level of peripheral blood micronucleated reticulocytes (MN-RET) increased dramatically within 48 h after whole body exposure for both proton or iron irradiated animals and returned to control levels within 1 week after treatment suggesting that these severely damaged transient cell populations are rapidly eliminated from the body. Mutation frequencies (MF) of the lacZ transgene increased as a function of proton dose in the spleen and brain tissues at 1, 8 and 16 wks post irradiation. We demonstrated that the MF of the lacZ target transgene was responsive to low doses of protons with significant increases in the MF (p 0.5 Gy iron ions. The overall magnitude of induction of lacZ MF in the brain is lower than that of the spleen, suggesting that radiation-induced genetic effects are tissue-specific, and tissue physiology plays a role in determining the late effects after particle radiation. This work was supported by NASA/NSBRI NCC 9-58-163

  4. Radiation damage and materials performance in irradiation environment

    International Nuclear Information System (INIS)

    Singh, B.N.

    2009-01-01

    Collisions of energetic projectile particles with host atoms produce atomic displacements in the target materials. Subsequently, some of these displacements are transformed into lattice defects and survive in the form of single defects and of defect clusters. Depending on the ambient temperature, these defects and their clusters diffuse, interact, annihilate, segregate and accumulate in various forms and are responsible for the evolution of the irradiation-induced microstructure. Naturally, both physical and mechanical properties and thereby the performance and lifetime of target materials are likely to be determined by the nature and the magnitude of the accumulated defects and their spatial dispositions. The defect accumulation, microstructural evolution and the resulting materials response gets very complicated particularly under the reactor operational conditions. The complication arises from the fact that the materials used in the structural components will experience concurrently generation of defects produced by the flux of neutrons and generation of dislocations due to plastic deformation. In other words, the defect accumulation will have to be considered under the conditions of two interactive reaction kinetics operating simultaneously. Both materials and experimental variables are likely to affect the damage accumulation and thereby the materials performance. Experimental and theoretical results pertaining to effects of major materials and experimental variables on materials performance will be briefly examined. (au)

  5. XAFS studies of radiation damage in nuclear materials

    Science.gov (United States)

    Olive, Daniel Thomas

    The growing demand for nuclear energy places a high importance on the development of new materials capable of withstanding higher temperatures and harsher irradiation conditions than those used in existing reactors. By supporting the development of next generation reactors it also becomes possible to close the nuclear fuel cycle, greatly reducing the amount of waste sent for disposal in deep geologic repositories, where its interaction with the environment is also a matter of interest. In this thesis, X-ray absorption fine structure (XAFS) spectroscopy is used to investigate the local atomic structure of systems of interest to nuclear energy. First, two XAFS studies on environmental materials are presented. Granular activated carbon (GAC) was treated with iron to improve its water remediation properties, specifically with respect to arsenic. XAFS was used to determine the nature of iron coating on the GAC surface, and the method of arsenic bonding to the treated surface. Next, a neodymium precipitate from solubility studies carried out for the Waste Isolation Pilot Plant (WIPP) was analyzed. Neodymium was used as an analog for plutonium in brine solutions. XAFS fitting indicated that the neodymium substituted for calcium in a gypsum lattice, providing information useful for future geochemical modeling. XAFS was also used to study radiation damage in materials. A candidate material for advanced reactor structural materials, modified 9Cr--1Mo, was irradiated to 1, 4, and 10 displacements per atom (dpa). XAFS analyses were performed on the Fe, Mo, and Nb K-edges. Irradiation caused a reduction in coordination for all three elements, but the exact behavior was element specific. Damage around Fe atoms was linear with dose, while damage around Mo atoms saturated at or before 1 dpa. XAFS was shown to provide a useful atomic level description of radiation damage for a complex alloy system. Finally, zirconium carbide and zirconium nitride, candidate materials for advanced

  6. Hydrogels as a Replacement Material for Damaged Articular Hyaline Cartilage

    Directory of Open Access Journals (Sweden)

    Charlotte M. Beddoes

    2016-06-01

    Full Text Available Hyaline cartilage is a strong durable material that lubricates joint movement. Due to its avascular structure, cartilage has a poor self-healing ability, thus, a challenge in joint recovery. When severely damaged, cartilage may need to be replaced. However, currently we are unable to replicate the hyaline cartilage, and as such, alternative materials with considerably different properties are used. This results in undesirable side effects, including inadequate lubrication, wear debris, wear of the opposing articular cartilage, and weakening of the surrounding tissue. With the number of surgeries for cartilage repair increasing, a need for materials that can better mimic cartilage, and support the surrounding material in its typical function, is becoming evident. Here, we present a brief overview of the structure and properties of the hyaline cartilage and the current methods for cartilage repair. We then highlight some of the alternative materials under development as potential methods of repair; this is followed by an overview of the development of tough hydrogels. In particular, double network (DN hydrogels are a promising replacement material, with continually improving physical properties. These hydrogels are coming closer to replicating the strength and toughness of the hyaline cartilage, while offering excellent lubrication. We conclude by highlighting several different methods of integrating replacement materials with the native joint to ensure stability and optimal behaviour.

  7. Laser induced damage in optical materials: ninth ASTM symposium.

    Science.gov (United States)

    Glass, A J; Guenther, A H

    1978-08-01

    The Ninth Annual Symposium on Optical Materials for High Power Lasers (Boulder Damage Symposium) was held at the National Bureau of Standards in Boulder, Colorado, 4-6 October 1977. The symposium was under the auspices of ASTM Committee F-1, Subcommittee on Laser Standards, with the joint sponsorship of NBS, the Defense Advanced Research Project Agency, the Department of Energy (formerly ERDA), and the Office of Naval Research. About 185 scientists attended, including representatives of the United Kingdom, France, Canada, Australia, Union of South Africa, and the Soviet Union. The Symposium was divided into sessions concerning Laser Windows and Materials, Mirrors and Surfaces, Thin Films, Laser Glass and Glass Lasers, and Fundamental Mechanisms. As in previous years, the emphasis of the papers was directed toward new frontiers and new developments. Particular emphasis was given to materials for use from 10.6 microm to the uv region. Highlights included surface characterization, thin film-substrate boundaries, and advances in fundamental laser-matter threshold interactions and mechanisms. The scaling of damage thresholds with pulse duration, focal area, and wavelength were also discussed. Alexander J. Glass of Lawrence Livermore Laboratory and Arthur H. Guenther of the Air Force Weapons Laboratory were co-chairpersons. The Tenth Annual Symposium is scheduled for 12-14 September 1978 at the National Bureau of Standards, Boulder, Colorado.

  8. Characterization of Structure and Damage in Materials in Four Dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, I. M. [Univ. of Illinois, Urbana, IL (United States); Schuh, C. A. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Vetrano, J. S. [U.S. Department of Energy, Washington, DC (United States); Browning, N. D. [Univ. of California, Davis, CA (United States); Field, D. P. [Washington State Univ., Pullman, WA (United States); Jensen, D. J. [Technical Univ. of Denmark, Roskilde (Denmark); Miller, M. K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Baker, I. [Darmouth College, Hanover, NH (United States); Dunand, D. C. [Northwestern Univ., Evanston, IL (United States); Dunin-Borkowski, R. [Technical Univ. of Denmark, Lyngby (Denmark); Kabius, B. [Argonne National Lab. (ANL), Argonne, IL (United States); Kelly, T. [Cameca Instruments Corp., Madison, WI (United States); Lozano-Perez, S. [Univ. of Oxford (United Kingdom); Misra, A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rohrer, G. S. [Carnegie Mellon Univ., Pittsburgh, PA (United States); Rollett, A. D. [Carnegie Mellon Univ., Pittsburgh, PA (United States); Taheri, M. [Drexel Univ., Philadelphia, PA (United States); Thompson, G. B. [Univ. of Alabama, Tuscaloosa, AL (United States); Uchic, M. [Air Force Research Lab. (AFRL), Wright-Patterson AFB, OH (United States); Wang, X. L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Was, G. [Univ. of Michigan, Ann Arbor, MI (United States)

    2010-09-30

    The materials characterization toolbox has recently experienced a number of parallel revolutionary advances, foreshadowing a time in the near future when materials scientists can quantify material structure across orders of magnitude in length and time scales (i.e., in four dimensions) completely. This paper presents a viewpoint on the materials characterization field, reviewing its recent past, evaluating its present capabilities, and proposing directions for its future development. Electron microscopy; atom-probe tomography; X-ray, neutron and electron tomography; serial sectioning tomography; and diffraction-based analysis methods are reviewed, and opportunities for their future development are highlighted. Particular attention is paid to studies that have pioneered the synergetic use of multiple techniques to provide complementary views of a single structure or process; several of these studies represent the state-of-the-art in characterization, and suggest a trajectory for the continued development of the field. Based on this review, a set of grand challenges for characterization science is identified, including suggestions for instrumentation advances, scientific problems in microstructure analysis, and complex structure evolution problems involving materials damage. The future of microstructural characterization is proposed to be one not only where individual techniques are pushed to their limits, but where the community devises strategies of technique synergy to address complex multiscale problems in materials science and engineering.

  9. Laser induced damage in optical materials: eleventh ASTM symposium.

    Science.gov (United States)

    Bennett, H E; Glass, A J; Guenther, A H; Newnam, B

    1980-07-15

    The eleventh Symposium on Optical Materials for High-Power Lasers (Boulder Damage Symposium) was held at the National Bureau of Standards in Boulder, Colorado, 30-31 October 1979. The symposium was held under the auspices of ASTM Committee F-1, Subcommittee on Laser Standards, with the joint sponsorship of NBS, the Defense Advanced Research Projects Agency, the Department of Energy, and the Office of Naval Research. About 150 scientists attended the symposium, including representatives of the United Kingdom, France, Canada, Japan, West Germany, and Denmark. The symposium was divided into sessions concerning transparent optical materials and the measurement of their properties, mirrors and surfaces, thin film characteristics, thin film damage, considerations for high-power systems, and finally theory and breakdown. As in previous years, the emphasis of the papers presented at the symposium was directed toward new frontiers and new developments. Particular emphasis was given to materials for high-power apparatus. The wavelength range of prime interest was from 10.6 microm to the UV region. Highlights included surface characterization, thin film-substrate boundaries, and advances in fundamental laser-matter threshold interactions and mechanisms. The scaling of damage thresholds with pulse duration, focal area, and wavelength was discussed in detail. Harold E. Bennett of the Naval Weapons Center, Alexander J. Glass of the Lawrence Livermore Laboratory, Arthur H. Guenther of the Air Force Weapons Laboratory, and Brian E. Newnam of the Los Alamos Scientific Laboratory were cochairpersons. The twelfth annual symposium is scheduled for 30 September-1 October 1980 at the National Bureau of Standards, Boulder, Colorado.

  10. Composite Beam Theory with Material Nonlinearities and Progressive Damage

    Science.gov (United States)

    Jiang, Fang

    Beam has historically found its broad applications. Nowadays, many engineering constructions still rely on this type of structure which could be made of anisotropic and heterogeneous materials. These applications motivate the development of beam theory in which the impact of material nonlinearities and damage on the global constitutive behavior has been a focus in recent years. Reliable predictions of these nonlinear beam responses depend on not only the quality of the material description but also a comprehensively generalized multiscale methodology which fills the theoretical gaps between the scales in an efficient yet high-fidelity manner. The conventional beam modeling methodologies which are built upon ad hoc assumptions are in lack of such reliability in need. Therefore, the focus of this dissertation is to create a reliable yet efficient method and the corresponding tool for composite beam modeling. A nonlinear beam theory is developed based on the Mechanics of Structure Genome (MSG) using the variational asymptotic method (VAM). The three-dimensional (3D) nonlinear continuum problem is rigorously reduced to a one-dimensional (1D) beam model and a two-dimensional (2D) cross-sectional analysis featuring both geometric and material nonlinearities by exploiting the small geometric parameter which is an inherent geometric characteristic of the beam. The 2D nonlinear cross-sectional analysis utilizes the 3D material models to homogenize the beam cross-sectional constitutive responses considering the nonlinear elasticity and progressive damage. The results from such a homogenization are inputs as constitutive laws into the global nonlinear 1D beam analysis. The theoretical foundation is formulated without unnecessary kinematic assumptions. Curvilinear coordinates and vector calculus are utilized to build the 3D deformation gradient tensor, of which the components are formulated in terms of cross-sectional coordinates, generalized beam strains, unknown warping

  11. Basic aspects of spallation radiation damage to materials

    Energy Technology Data Exchange (ETDEWEB)

    Wechsler, M.S.; Lin, C. [North Carolina State Univ., Raleigh, NC (United States); Sommer, W.F. [Los Alamos National Laboratory, NM (United States)

    1995-10-01

    The nature of radiation effects, as learned from investigations using reactor neutron irradiations, is reviewed, and its relevance to spallation radiation damage to materials in accelerator-driven neutron sources is discussed. Property changes upon irradiation are due to (1) displaced atoms, producing vacancy and interstitial defect clusters, which cause radiation hardening and embrittlement; (2) helium production, the helium then forming bubbles, which engenders high-temperature grain-boundary fracture; and (3) transmutations, which means that impurity concentrations are introduced. Methods for analyzing displacement production are related, and recent calculations of displacement cross sections using SPECTER and LAHET are described, with special reference to tungsten, a major candidate for a target material in accelerator-driven neutron systems.

  12. Radiation damage in materials. Primary knock-on atom energy analyses of cascade damage

    International Nuclear Information System (INIS)

    Sekimura, Naoto

    1995-01-01

    To understand cascade damage formation as a function of primary recoil energy, thin foils of gold were irradiated with 20 - 400 keV self-ions to 1.0 x 10 14 ions/m 2 at 300 K. Yield of groups of vacancy clusters saturated at ion energy higher than 100 keV. Number of clusters in a group had variation even from the same energy ions. Size distribution of the clusters was not strongly dependent on number of clusters in a group and ion energy. Density of vacancy clusters in a group formed near the specimen surface was calibrated to estimate vacancy cluster formation in neutron-irradiated material. A model was proposed to predict distribution of defect clusters in the irradiated materials based on a primary recoil spectrum. Examples of recomposed distribution of vacancy clusters in a group in irradiated gold were compared with the measured data. (author)

  13. Materials surface damage and modification under high power plasma exposures

    Science.gov (United States)

    Garkusha, I.; Makhlaj, V.; Byrka, O.; Taran, V.; Voitsenya, V.; Malykhin, S.; Herashchenko, S.; Surovitskiy, S.; Nowakowska-Langier, K.; Sadowski, M. J.; Skladnik-Sadowska, E.; Terentyev, D.

    2018-01-01

    Influence of powerful plasma impacts on several materials used for the construction of energy systems, i.e. different grades of steels as well as tungsten coatings, has been discussed. Irradiations of these materials with hydrogen and helium plasma streams have been performed in several high-current-pulse and quasi-stationary plasma accelerators which provided the variation of a power load upon the exposed surface as well as changes of the particle flux in wide ranges: the energy flux density in the range of 1-25 MJ/m2, particle flux - up to 1026-1029 ion/m2s, the plasma stream velocity - up to about 500 km/s, and the pulse duration in the range of 1-250 μs. A response of the investigated materials to extreme plasma loads, which are relevant to transient events in fusion reactors, is briefly discussed. It is demonstrated that a broad combination of mechanisms of powerful plasma interactions with various materials includes not only a surface damage caused by different erosion mechanisms, but under certain conditions it may also result in a significant improvement of material properties in the near-surface surface layer of several tens-μm in thickness. Some improvement of the structure and substructure of such a layer may be caused by the high-speed quenching, the shock wave formation and material alloying with plasma- and coating-species. The creation of unique surface structures and a considerable improvement of physical and mechanical properties of different materials can be achieved by the pulsed plasma alloying, i.e. pre-deposited coating modifications and mixing caused by the impacting plasma streams.

  14. Laser induced damage in optical materials: twelfth ASTM symposium.

    Science.gov (United States)

    Bennett, H E; Glass, A J; Guenther, A H; Newnam, B

    1981-09-01

    The twelfth annual Symposium on Optical Materials for High Power Lasers (Boulder Damage Symposium) was held at the National Bureau of Standards in Boulder, Colorado, 30 Sept.-l Oct., 1980. The symposium was held under the auspices of ASTM Committee F-l, Subcommittee on Laser Standards, with the joint sponsorship of NBS, the Defense Advanced Research Projects Agency, the Department of Energy, the Office of Naval Research, and the Air Force Office of Scientific research. Over 150 scientists attended the symposium, including representatives of the United Kingdom, France, Japan, and West Germany. The symposium was divided into sessions concerning materials and measurements, mirrors and surfaces, thin films, and finally fundamental mechanisms. As in previous years, the emphasis of the papers presented at the symposium was directed toward new frontiers and new developments. Particular emphasis was given to materials for high power systems. The wavelength range of prime interest was from 10.6 microm to the UV region. Highlights included surface characterization, thin film-substrate boundaries, and advances in fundamental laser-matter threshold interactions and mechanisms. The scaling of damage thresholds with pulse duration, focal area, and wavelength was discussed in detail. Harold E. Bennett of the Naval Weapons Center, Alexander J. Glass of the Lawrence Livermore National Laboratory, Arthur H. Guenther of the Air Force Weapons Laboratory, and Brian E. Newnam of the Los Alamos National Laboratory were cochairmen of the symposium. The thirteenth annual symposium is scheduled for 17-18 Nov. 1981 at the National Bureau of Standards, Boulder, Colorado.

  15. Characterization of genetic miscoding lesions caused by postmortem damage

    DEFF Research Database (Denmark)

    Gilbert, M Thomas P; Hansen, Anders J; Willerslev, Eske

    2002-01-01

    The spectrum of postmortem damage in mitochondrial DNA was analyzed in a large data set of cloned sequences from ancient human specimens. The most common forms of damage observed are two complementary groups of transitions, termed "type 1" (adenine-->guanine/thymine-->cytosine) and "type 2" (cyto...

  16. Laser-induced damage in optical materials: sixteenth ASTM symposium.

    Science.gov (United States)

    Bennett, H E; Guenther, A H; Milam, D; Newnam, B E

    1987-03-01

    The Sixteenth Annual Symposium on Optical Materials for High Power Lasers (Boulder Damage Symposium) was held at the National Bureau of Standards in Boulder, CO, 15-17 Oct. 1984. The Symposium was held under the auspices of ASTM Committee F-1, Subcommittee on Laser Standards, with the joint sponsorship of NBS, the Defense Advanced Research Project Agency, the Department of Energy, the Office of Naval Research, and the Air Force Office of Scientific Research. Approximately 180 scientists attended the Symposium, including representatives from England, France, The Netherlands, Scotland, and West Germany. The Symposium was divided into sessions concerning Materials and Measurements, Mirrors and Surfaces, Thin Films, and Fundamental Mechanisms. As in previous years, the emphasis of the papers presented at the Symposium was directed toward new frontiers and new developments. Particular emphasis was given to materials for high-power apparatus. The wavelength range of prime interest was from 10.6,microm to the UV region. Highlights included surface characterization, thin-film-substrate boundaries, and advances in fundamental laser-matter threshold interactions and mechanisms. Harold E. Bennett of the U.S. Naval Weapons Center, Arthur H. Guenther of the U.S. Air Force Weapons Laboratory, David Milam of the Lawrence Livermore National Laboratory, and Brian E. Newnam of the Los Alamos National Laboratory were cochairmen of the Symposium.

  17. Biobanking genetic material for agricultural animal species

    Science.gov (United States)

    Biobanking animal germplasm and tissues is a major component of conserving genetic resources. Effectively constructing such gene banks requires an understanding and evaluation of genetic resources, the ability to conserve various tissues through cryopreservation, and a robust information technology ...

  18. Optimized adhesives for strong, lightweight, damage-resistant, nanocomposite materials: new insights from natural materials

    International Nuclear Information System (INIS)

    Hansma, P K; Turner, P J; Ruoff, R S

    2007-01-01

    From our investigations of natural composite materials such as abalone shell and bone we have learned the following. (1) Nature is frugal with resources: it uses just a few per cent glue, by weight, to glue together composite materials. (2) Nature does not avoid voids. (3) Nature makes optimized glues with sacrificial bonds and hidden length. We discuss how optimized adhesives combined with high specific stiffness/strength structures such as carbon nanotubes or graphene sheets could yield remarkably strong, lightweight, and damage-resistant materials

  19. Optimized adhesives for strong, lightweight, damage-resistant, nanocomposite materials: new insights from natural materials

    Energy Technology Data Exchange (ETDEWEB)

    Hansma, P K [Physics Department, Broida Hall, University of California, Santa Barbara, CA 93106 (United States); Turner, P J [Physics Department, Broida Hall, University of California, Santa Barbara, CA 93106 (United States); Ruoff, R S [Department of Mechanical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3111 (United States)

    2007-01-31

    From our investigations of natural composite materials such as abalone shell and bone we have learned the following. (1) Nature is frugal with resources: it uses just a few per cent glue, by weight, to glue together composite materials. (2) Nature does not avoid voids. (3) Nature makes optimized glues with sacrificial bonds and hidden length. We discuss how optimized adhesives combined with high specific stiffness/strength structures such as carbon nanotubes or graphene sheets could yield remarkably strong, lightweight, and damage-resistant materials.

  20. Acoustic damage detection in laser-cut CFRP composite materials

    Science.gov (United States)

    Nishino, Michiteru; Harada, Yoshihisa; Suzuki, Takayuki; Niino, Hiroyuki

    2012-03-01

    Carbon fiber reinforced plastics (CFRP) composite material, which is expected to reduce the weight of automotive, airplane and etc., was cut by laser irradiation with a pulsed-CO2 laser (TRUMPF TFL5000; P=800W, 20kHz, τ=8μs, λ=10.6μm, V=1m/min) and single-mode fiber lasers (IPG YLR-300-SM; P=300W, λ=1.07μm, V=1m/min)(IPG YLR- 2000-SM; P=2kW, λ=1.07μm, V=7m/min). To detect thermal damage at the laser cutting of CFRP materials consisting of thermoset resin matrix and PAN or PITCH-based carbon fiber, the cut quality was observed by X-ray CT. The effect of laser cutting process on the mechanical strength for CFRP tested at the tensile test. Acoustic emission (AE) monitoring, high-speed camera and scanning electron microscopy were used for the failure process analysis. AE signals and fractographic features characteristic of each laser-cut CFRP were identified.

  1. Damage Precursor Investigation of Fiber-Reinforced Composite Materials Under Fatigue Loads

    Science.gov (United States)

    2013-09-01

    capability, needs Maintenance Action Damage Detection by NDE and/or in-situ sensors (Ultrasonic, Thermography , Acoustic Emission, etc.) Incipient... Damage Prognosis for Materials and Structures in Complex Systems, AFOSR Discovery Challenge Thrust (DCT) Workshop on Prognosis of Aircraft and Space... Damage Precursor Investigation of Fiber-Reinforced Composite Materials Under Fatigue Loads by Asha J. Hall, Raymond E. Brennan IV, Anindya

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

    Science.gov (United States)

    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

  3. Stress and Damage in Polymer Matrix Composite Materials Due to Material Degradation at High Temperatures

    Science.gov (United States)

    McManus, Hugh L.; Chamis, Christos C.

    1996-01-01

    This report describes analytical methods for calculating stresses and damage caused by degradation of the matrix constituent in polymer matrix composite materials. Laminate geometry, material properties, and matrix degradation states are specified as functions of position and time. Matrix shrinkage and property changes are modeled as functions of the degradation states. The model is incorporated into an existing composite mechanics computer code. Stresses, strains, and deformations at the laminate, ply, and micro levels are calculated, and from these calculations it is determined if there is failure of any kind. The rationale for the model (based on published experimental work) is presented, its integration into the laminate analysis code is outlined, and example results are given, with comparisons to existing material and structural data. The mechanisms behind the changes in properties and in surface cracking during long-term aging of polyimide matrix composites are clarified. High-temperature-material test methods are also evaluated.

  4. Nondestructive characterization of materials damage; Zerstoerungsfreie Charakterisierung von Werkstoffschaedigung

    Energy Technology Data Exchange (ETDEWEB)

    Dobmann, G. [Fraunhofer Inst. fuer Zerstoerungsfreie Pruefverfahren, IZFP, Saarbruecken (Germany)

    1999-08-01

    The paper discusses two examples of application of NDT for early detection of materials damage, or ageing effects. The first case shows the potential of micromagnetic testing techniques for early detection of hydrogen-induced stress corrosion cracking in pipework. Pipe specimens made of steel X20Cr13, which differed in materials state induced by various heat treatments, were exposed to corrosive attack induced in a closed cycle by simultaneous rinsing with NACE solution and stress application through stamp impact. Various micromagnetic testing parameters were measured at the specimens` outside surface during the annealing period. Further, fatigue experiments were made with specimen sets made of steel 1.4541, under various mechanical and temperature stresses (room temperature and 300 C), for measuring the remanent magnetization of the cylindrical fatigue test blocks (equal geometry) cut out of the specimens, in order to conclude information on the martensite content and the fatigue effects. (Orig./CB) [Deutsch] In diesem Beitrag werden zwei Beispiele der ZFP zur Frueherkennung von Werkstoffschaedigung und Alterungserscheinungen diskutiert. Zum einen wurde das Potential mikromagnetischer Pruefverfahren zur Frueherkennung wasserstoffinduzierter, auch kathodische Spannungsrisskorrosion genannt (HISCC, hydrogene induced stress corrosion cracking), an Rohrleitungen nachgewiesen. Rohrproben unterschiedlicher Waermebehandlungszustaende der Stahlguete X20Cr13 wurden durch gleichzeitiges Spuelen mit NACE-Loesung in einem geschlossenen Kreislauf und Beaufschlagen einer Spannung durch Stempeldruck dem Korrosionsangriff ausgesetzt. Waehrend der Auslagerung wurden verschiedene mikromagnetische Pruefgroessen an der Aussenseite der Rohrproben aufgenommen. Zum anderen wurden an Probensaetzen der Stahlqualitaet 1.4541 Ermuedungsexperimente bei unterschiedlichen mechanischen und Temperaturbelastungen (bei Raumtemperatur und 300 C) durchgefuehrt. Das Ziel war die Messung der

  5. Assessment of the material properties of a fire damaged building

    Directory of Open Access Journals (Sweden)

    Oladipupo OLOMO

    2012-12-01

    Full Text Available This study identifies a process for assessing the material properties of a fire damaged building so as to determine whether the remains can be utilized in construction or be demolished. Physical and chemical analysis were carried out on concrete and steel samples taken from various elements of the building after thorough visual inspection of the entire building had been conducted. The physical (non-destructive tests included the Schmidt hammer and ultrasonic pulse velocity tests on the concrete samples, tensile strength test on the steel samples and chemical tests involving the assessment of the quantities of cement, sulphates and chloride concentrations in the samples. A redesign of the building elements was also carried out and the results were compared with the existing design. The non-destructive test results indicated compressive strengths as low as 9.9 N/mm2, the tensile strength test indicated a maximum strength of 397.48 N/mm2 and the chemical test indicated chloride contents as high as 0.534 g per gramme of concrete. These properties deviated significantly from standard requirements. Based on these results, it was concluded that the remains of the building should be demolished.

  6. Radiation damage in diatomic materials at high doses

    International Nuclear Information System (INIS)

    Hobbs, L.W.; Hughes, A.E.

    1975-10-01

    Radiation effects in diatomic materials can differ structurally from those in metals because of the need to take into account different displacement rates on the two sublattices and the inevitable stoichiometric implications; in most diatomic insulators the anion species has the greater displacement cross section. Anion point defect stabilisation in heavily-irradiated (0.1 to 10 dpa) diatomic insulators has been studied using radiolysis of alkali and alkaline earth halides. A temperatures > 0.3 Tsub(m), all anion defects are mobile and can aggregate. Aggregation of anion interstitials results in creation of perfect dislocation loops without the need for primary cation displacements; simultaneous formation of substitutional anion molecular centres provides the necessary cation interstitials. Aggregation of anion vacancies leads to formation of metallic inclusions of the cation species, in some cases in an ordered array, which is the analogue, on a single sublattice, to the void lattice in metals. Availability of sinks for both anion interstitials and anion vacancies yields defect growth kinetics similar to those observed during formation of voids in irradiated metals, and a very high level of damage (approximately 10%) can be sustained in the lattice. The width of the temperature region concerned is much narrower, however, due to the possibility of recombination of aggregated or re-emitted anion vacancies with mobile or dispersed anion molecular defects; the latter can also aggregate to form fluid anion molecular inclusions and so complete the decomposition of the solid into separate phases of its constituent elements. (author)

  7. Damage identification on spatial Timoshenko arches by means of genetic algorithms

    Science.gov (United States)

    Greco, A.; D'Urso, D.; Cannizzaro, F.; Pluchino, A.

    2018-05-01

    In this paper a procedure for the dynamic identification of damage in spatial Timoshenko arches is presented. The proposed approach is based on the calculation of an arbitrary number of exact eigen-properties of a damaged spatial arch by means of the Wittrick and Williams algorithm. The proposed damage model considers a reduction of the volume in a part of the arch, and is therefore suitable, differently than what is commonly proposed in the main part of the dedicated literature, not only for concentrated cracks but also for diffused damaged zones which may involve a loss of mass. Different damage scenarios can be taken into account with variable location, intensity and extension of the damage as well as number of damaged segments. An optimization procedure, aiming at identifying which damage configuration minimizes the difference between its eigen-properties and a set of measured modal quantities for the structure, is implemented making use of genetic algorithms. In this context, an initial random population of chromosomes, representing different damage distributions along the arch, is forced to evolve towards the fittest solution. Several applications with different, single or multiple, damaged zones and boundary conditions confirm the validity and the applicability of the proposed procedure even in presence of instrumental errors on the measured data.

  8. Radiation-induced genetic damage and the prostaglandin system

    International Nuclear Information System (INIS)

    Das, U.N.; Rama Devi, G.

    1988-01-01

    Radiation is one of the sheet anchors of cancer therapy. More often than not radiation is used in combination with anticancer drugs and surgery in the management of cancer. The death of any cell can be observed if the dose of radiation to which it is exposed is sufficiently high. However, after low doses of radiation (precise values vary with the tissue) disturbances in cell proliferation can be observed which may include interference with mitosis and DNA synthesis. This can lead to the formation of cells with abnormal DNA, with qualitative and/or quantitative abnormalities. These effects of radiation are seen mainly in the tissues undergoing continual renewal such as mucosa, bone marrow, gonads etc., and the spectrum of damage ranging from progressive hypoplesia to total atrophy, depending on the dose. One of the late effects of radiation is the development of cancer

  9. Self-Healing Structural Materials for Damage Tolerant Aerospace Vehicles

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed  effort describes how to develop novel lightweight, self-healing systems where self-repair is induced by the forces imparted by the damage event itself....

  10. Neutron and gamma irradiation damage to organic materials.

    Energy Technology Data Exchange (ETDEWEB)

    White, Gregory Von, II; Bernstein, Robert

    2012-04-01

    This document discusses open literature reports which investigate the damage effects of neutron and gamma irradiation on polymers and/or epoxies - damage refers to reduced physical chemical, and electrical properties. Based on the literature, correlations are made for an SNL developed epoxy (Epon 828-1031/DDS) with an expected total fast-neutron fluence of {approx}10{sup 12} n/cm{sup 2} and a {gamma} dosage of {approx}500 Gy received over {approx}30 years at < 200 C. In short, there are no gamma and neutron irradiation concerns for Epon 828-1031/DDS. To enhance the fidelity of our hypotheses, in regards to radiation damage, we propose future work consisting of simultaneous thermal/irradiation (neutron and gamma) experiments that will help elucidate any damage concerns at these specified environmental conditions.

  11. The History of Patenting Genetic Material.

    Science.gov (United States)

    Sherkow, Jacob S; Greely, Henry T

    2015-01-01

    The US Supreme Court's recent decision in Association for Molecular Pathology v. Myriad Genetics, Inc. declared, for the first time, that isolated human genes cannot be patented. Many have wondered how genes were ever the subjects of patents. The answer lies in a nuanced understanding of both legal and scientific history. Since the early twentieth century, "products of nature" were not eligible to be patented unless they were "isolated and purified" from their surrounding environment. As molecular biology advanced, and the capability to isolate genes both physically and by sequence came to fruition, researchers (and patent offices) began to apply patent-law logic to genes themselves. These patents, along with other biological patents, generated substantial social and political criticism. Myriad Genetics, a company with patents on BRCA1 and BRCA2, two genes critical to assessing early-onset breast and ovarian cancer risk, and with a particularly controversial business approach, became the antagonist in an ultimately successful campaign to overturn gene patents in court. Despite Myriad's defeat, some questions concerning the rights to monopolize genetic information remain. The history leading to that defeat may be relevant to these future issues.

  12. Thermomechanics of damageable materials under diffusion: modelling and analysis

    Science.gov (United States)

    Roubíček, Tomáš; Tomassetti, Giuseppe

    2015-12-01

    We propose a thermodynamically consistent general-purpose model describing diffusion of a solute or a fluid in a solid undergoing possible phase transformations and damage, beside possible visco-inelastic processes. Also heat generation/consumption/transfer is considered. Damage is modelled as rate-independent. The applications include metal-hydrogen systems with metal/hydride phase transformation, poroelastic rocks, structural and ferro/para-magnetic phase transformation, water and heat transport in concrete, and if diffusion is neglected, plasticity with damage and viscoelasticity, etc. For the ensuing system of partial differential equations and inclusions, we prove existence of solutions by a carefully devised semi-implicit approximation scheme of the fractional-step type.

  13. Study of genetic damage in the Japanese oyster induced by an environmentally-relevant exposure to diuron: evidence of vertical transmission of DNA damage.

    Science.gov (United States)

    Barranger, A; Akcha, F; Rouxel, J; Brizard, R; Maurouard, E; Pallud, M; Menard, D; Tapie, N; Budzinski, H; Burgeot, T; Benabdelmouna, A

    2014-01-01

    Pesticides represent a major proportion of the chemical pollutants detected in French coastal waters and hence a significant environmental risk with regards to marine organisms. Commercially-raised bivalves are particularly exposed to pollutants, among them pesticides, as shellfish farming zones are subject to considerable pressure from agricultural activities on the mainland. The aims of this study were to determine (1) the genotoxic effects of diuron exposure on oyster genitors and (2) the possible transmission of damaged DNA to offspring and its repercussions on oyster fitness. To investigate these points, oysters were exposed to concentrations of diuron close to those detected in the Marennes-Oleron Basin (two 7-day exposure pulses at 0.4 and 0.6 μg L(-1)) during the gametogenesis period. Genomic abnormalities were characterized using two complementary approaches. The Comet assay was applied for the measurement of early and reversible primary DNA damage, whereas flow cytometry was used to assess the clastogenic and aneugenic effect of diuron exposure. Polar Organic Chemical Integrative Samplers (POCIS) were used in exposed and assay tanks to confirm the waterborne concentration of diuron reached during the experiment. The results obtained by the Comet assay clearly showed a higher level of DNA strand breaks in both the hemocytes and spermatozoa of diuron-exposed genitors. The transmission of damaged genetic material to gamete cells could be responsible for the genetic damage measured in offspring. Indeed, flow cytometry analyses showed the presence of DNA breakage and a significant decrease in DNA content in spat from diuron-exposed genitors. The transmission of DNA damage to the offspring could be involved in the negative effects observed on offspring development (decrease in hatching rate, higher level of larval abnormalities, delay in metamorphosis) and growth. In this study, the vertical transmission of DNA damage was so highlighted by subjecting oyster

  14. Both genetic and dietary factors underlie individual differences in DNA damage levels and DNA repair capacity

    Czech Academy of Sciences Publication Activity Database

    Slyšková, Jana; Lorenzo, Y.; Karlsen, A.; Carlsen, M. H.; Novosadová, Vendula; Blomhoff, R.; Vodička, Pavel; Collins, A. R.

    2014-01-01

    Roč. 16, APR 2014 (2014), s. 66-73 ISSN 1568-7864 R&D Projects: GA ČR(CZ) GAP304/12/1585 Institutional support: RVO:68378041 ; RVO:86652036 Keywords : DNA damage * DNA repair capacity * diet Subject RIV: EB - Genetics ; Molecular Biology; EI - Biotechnology ; Bionics (BTO-N) Impact factor: 3.111, year: 2014

  15. Acute crack cocaine exposure induces genetic damage in multiple organs of rats.

    Science.gov (United States)

    Moretti, Eduardo Gregolin; Yujra, Veronica Quispe; Claudio, Samuel Rangel; Silva, Marcelo Jose Dias; Vilegas, Wagner; Pereira, Camilo Dias Seabra; de Oliveira, Flavia; Ribeiro, Daniel Araki

    2016-04-01

    Crack cocaine is a very toxic product derived from cocaine. The aim of this study was to evaluate genetic damage in multiple organs of rats following acute exposure to crack cocaine. A total of 20 Wistar rats were distributed into four groups (n = 5), as follows: 0, 4.5, 9, and 18 mg/kg body weight (b.w.) of crack cocaine administered by intraperitoneal route (i.p.). All animals were killed 24 h after intraperitoneal (i.p.) injection. The results showed that crack cocaine increased the number of micronucleated cells in bone marrow cells exposed to 18 mg/kg crack cocaine (p genetic damage as depicted by single cell gel (comet) assay at 9 and 18 mg/kg doses (p cocaine at 9 and 18 mg/kg (p cocaine is able to induce genomic damage in multiple organs of Wistar rats.

  16. Multi-physics modeling of multifunctional composite materials for damage detection

    Science.gov (United States)

    Sujidkul, Thanyawalai

    This study presents a modeling of multifunction composite materials for damage detection with its verification and validation to mechanical behavior predictions of Carbon Fibre Reinforced Polymer composites (CFRPs), CFRPs laminated composites, and woven SiC/SiC matrix composites that are subjected to fracture damage. Advantages of those materials are low cost, low density, high strength-to-weight ratio, and comparable specific tensile properties, the special of SiC/SiC is good environmental stability at high temperature. Resulting in, the composite has been used for many important structures such as helicopter rotors, aerojet engines, gas turbines, hot control surfaces, sporting goods, and windmill blades. Damage or material defect detection in a mechanical component can provide vital information for the prediction of remaining useful life, which will result in the prevention of catastrophic failures. Thus the understanding of the mechanical behavior have been challenge to the prevent damage and failure of composites in different scales. The damage detection methods in composites have been investigated widely in recent years. Non-destructive techniques are the traditional methods to detect the damage such as X-ray, acoustic emission and thermography. However, due to the invisible damage in composite can be occurred, to prevent the failure in composites. The developments of damage detection methods have been considered. Due to carbon fibers are conductive materials, in resulting CFRPs can be self-sensing to detect damage. As is well known, the electrical resistance has been shown to be a sensitive measure of internal damage, and also this work study in thermal resistance can detect damage in composites. However, there is a few number of different micromechanical modeling schemes has been proposed in the published literature for various types of composites. This works will provide with a numerical, analytical, and theoretical failure models in different damages to

  17. Thermomechanics of damageable materials under diffusion: modelling and analysis

    Czech Academy of Sciences Publication Activity Database

    Roubíček, Tomáš; Tomassetti, G.

    2015-01-01

    Roč. 66, č. 6 (2015), s. 3535-3572 ISSN 0044-2275 R&D Projects: GA ČR GAP201/10/0357 Institutional support: RVO:61388998 Keywords : visco-elastic porous solids * incomplete damage * diffusion driven by chemical-potential gradient Subject RIV: BA - General Mathematics Impact factor: 1.560, year: 2015 http://link.springer.com/article/10.1007/s00033-015-0566-2

  18. ITER transient consequences for material damage: modelling versus experiments

    Science.gov (United States)

    Bazylev, B.; Janeschitz, G.; Landman, I.; Pestchanyi, S.; Loarte, A.; Federici, G.; Merola, M.; Linke, J.; Zhitlukhin, A.; Podkovyrov, V.; Klimov, N.; Safronov, V.

    2007-03-01

    Carbon-fibre composite (CFC) and tungsten macrobrush armours are foreseen as PFC for the ITER divertor. In ITER the main mechanisms of metallic armour damage remain surface melting and melt motion erosion. In the case of CFC armour, due to rather different heat conductivities of CFC fibres a noticeable erosion of the PAN bundles may occur at rather small heat loads. Experiments carried out in the plasma gun facilities QSPA-T for the ITER like edge localized mode (ELM) heat load also demonstrated significant erosion of the frontal and lateral brush edges. Numerical simulations of the CFC and tungsten (W) macrobrush target damage accounting for the heat loads at the face and lateral brush edges were carried out for QSPA-T conditions using the three-dimensional (3D) code PHEMOBRID. The modelling results of CFC damage are in a good qualitative and quantitative agreement with the experiments. Estimation of the droplet splashing caused by the Kelvin-Helmholtz (KH) instability was performed.

  19. ITER transient consequences for material damage: modelling versus experiments

    International Nuclear Information System (INIS)

    Bazylev, B; Janeschitz, G; Landman, I; Pestchanyi, S; Loarte, A; Federici, G; Merola, M; Linke, J; Zhitlukhin, A; Podkovyrov, V; Klimov, N; Safronov, V

    2007-01-01

    Carbon-fibre composite (CFC) and tungsten macrobrush armours are foreseen as PFC for the ITER divertor. In ITER the main mechanisms of metallic armour damage remain surface melting and melt motion erosion. In the case of CFC armour, due to rather different heat conductivities of CFC fibres a noticeable erosion of the PAN bundles may occur at rather small heat loads. Experiments carried out in the plasma gun facilities QSPA-T for the ITER like edge localized mode (ELM) heat load also demonstrated significant erosion of the frontal and lateral brush edges. Numerical simulations of the CFC and tungsten (W) macrobrush target damage accounting for the heat loads at the face and lateral brush edges were carried out for QSPA-T conditions using the three-dimensional (3D) code PHEMOBRID. The modelling results of CFC damage are in a good qualitative and quantitative agreement with the experiments. Estimation of the droplet splashing caused by the Kelvin-Helmholtz (KH) instability was performed

  20. Damage detection of truss structures using two-stage optimization based on micro genetic algorithm

    International Nuclear Information System (INIS)

    Kim, Nam Il; Kim, Hyung Min; Lee, Jae Hong

    2014-01-01

    A simple and efficient two-stage optimization procedure is proposed to properly identify the sites and the extent of multiple damages in truss structures. In the first stage, the most potentially damaged elements are identified using an anti-optimization (AO) technique. In the second stage, a micro genetic algorithm (MGA) is performed to accurately determine the actual damage extents based on a priori knowledge from the first stage. The correctness and effectiveness of the proposed algorithm are proved by two illustrated test examples: the planar and space truss models with the numerically simulated data. The numerical results show the computational advantages of the proposed method to precisely determine the sites and the extent of multiple damages of truss structures.

  1. Damage Mechanisms and Crack Growth in a Particulate Composite Material

    National Research Council Canada - National Science Library

    Liu, C

    1998-01-01

    ... industries for their improved performance over the matrix material in, for example, thermal and electrical conductivities, friction and wear resistance, machinability, surface hardness, and cost effective...

  2. Characteristics of Creep Damage for 60Sn-40Pb Solder Material

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-08-26

    This paper presents a viscoplasticity model taking into account the effects of change in grain or phase size and damage on the characterization of creep damage in 60Sn-40Pb solder. Based on the theory of damage mechanics, a two-scalar damage model is developed for isotropic materials by introducing the free energy equivalence principle. The damage evolution equations are derived in terms of the damage energy release rates. In addition, a failure criterion is developed based on the postulation that a material element is said to have ruptured when the total damage accumulated in the element reaches a critical value. The damage coupled viscoplasticity model is discretized and coded in a general-purpose finite element program known as ABAQUS through its user-defined material subroutine UMAT. To illustrate the application of the model, several example cases are introduced to analyze, both numerically and experimentally, the tensile creep behaviors of the material at three stress levels. The model is then applied to predict the deformation of a notched specimen under monotonic tension at room temperature (22 C). The results demonstrate that the proposed model can successfully predict the viscoplastic behavior of the solder material.

  3. Damage thresholds of thin film materials and high reflectors at 248 nm

    Energy Technology Data Exchange (ETDEWEB)

    Rainer, F.; Lowdermilk, W.H.; Milam, D.; Carniglia, C.K.; Hart, T.T.; Lichtenstein, T.L.

    1982-01-01

    Twenty-ns, 248-nm KrF laser pulses were used to measure laser damage thresholds for halfwave-thick layers of 15 oxide and fluoride coating materials, and for high reflectance coatings made with 13 combinations of these materials. The damage thresholds of the reflectors and single-layer films were compared to measurements of several properties of the halfwave-thick films to determine whether measurements of these properties of single-layer films to determine whether measurements of these properties of single-layer films were useful for identifying materials for fabrication of damage resistant coatings.

  4. Physics of radiation damage and radiation materials technology

    International Nuclear Information System (INIS)

    1994-01-01

    Materials of the meeting ''Nuclear power in Ukraine'' are published in the present issue. The meeting was held i Alushta, 28 September - 3 October 1993. Important issues of nuclear power development in Ukraine are considered, including creation of the nuclear fuel cycle, nuclear safety and economics. Part of materials are devoted to discussing projects of advanced reactors

  5. Damage of multilayer polymer materials under creep loading

    Czech Academy of Sciences Publication Activity Database

    Zouhar, Michal; Hutař, Pavel; Náhlík, Luboš; Knésl, Zdeněk

    2011-01-01

    Roč. 465, - (2011), s. 153-156 ISSN 1013-9826 R&D Projects: GA ČR GA106/09/0279; GA ČR GC101/09/J027 Institutional research plan: CEZ:AV0Z20410507 Keywords : CMOD * material interface * creep * fracture mechanics Subject RIV: JL - Materials Fatigue, Friction Mechanics

  6. CISM Course on Damage and Fracture of Disordered Materials

    CERN Document Server

    Mier, Jan

    2000-01-01

    The principal objective of this book is to relate the random distributions of defects and material strength on the microscopic scale with the deformation and residual strength of materials on the macroscopic scale. To reach this goal the authors considered experimental, analytical and computational models on atomic, microscopic and macroscopic scales.

  7. Material damage in graphite by run-away electrons

    Energy Technology Data Exchange (ETDEWEB)

    Hoven, H.; Koizlik, K.; Linke, J.; Nickel, H.; Wallura, E.; Kohlhaas, W.

    1989-04-01

    Graphite limiters in the KFA tokamak TEXTOR have been hit by run-away electrons, which ''burned'' craters into the material surface. The craters have been formed by material erosion and/or sublimation and by chipping of thin laminates from the surface and additionally by redeposition of graphitic material. Moreover, thin metallic layers have been detected which may have been redeposited independently from the run-away electron event, and which could be found also outside the run-away electron crater. The redeposited carbon showed primarily two types of structure, namely oriented pyrocarbon and carbon-black-like material. The crater has been investigated by metallography, optical microscopy, secondary electron microscopy combined with energy-dispersive X-ray analysis, and automatic quantitative image analysis. The examined parameters are crater geometry, cracking behaviour and type and structure of redeposited material. (orig.).

  8. Genetic damage in the bivalve mollusk Corbicula fluminea induced by the water-soluble fraction of gasoline.

    Science.gov (United States)

    Fedato, R P; Simonato, J D; Martinez, C B R; Sofia, S H

    2010-07-19

    Although gasoline is an important contaminant of aquatic ecosystems, information concerning the potential effects of this petroleum derivative on the DNA of aquatic biota is lacking. The present study aimed to evaluate the genotoxic and mutagenic effects of acute exposures (6, 24, and 96h) to gasoline water-soluble fraction (GWSF), diluted to 5%, on the Asian clam Corbicula fluminea. The comet assay and the micronucleus (MN) test were performed on hemocytes and gill cells of C. fluminea. For the three different times tested, the comet assay indicated DNA damage in hemocytes and gill cells of C. fluminea exposed to GWSF. The MN test detected significant damage in the genetic material of the hemocytes only after 96h of exposure to GWSF. The recovery capacity of organisms previously exposed for 6h to GWSF was also evaluated with the comet assay. The results revealed a great capacity of this species to repair DNA damage; following 6h of recovery, the comet score returned to that of the control groups. Overall, our findings indicate that GWSF has genotoxic and mutagenic effects on C. fluminea. In addition, the present results confirm the sensitivity of C. fluminea to damage caused by exposure to environmental contaminants, and, therefore, its suitability for use in environmental monitoring studies. Copyright 2010 Elsevier B.V. All rights reserved.

  9. Comet assay to determine genetic damage by the use of ivermectin in zebu cows (Bos taurus indicus

    Directory of Open Access Journals (Sweden)

    Donicer Montes-Vergara

    2017-05-01

    Full Text Available Objective. The objective of the work was evaluate the damage genetic caused by the use of ivermectin (IVM in cows zebu to concentrations of 1% and 3.15% through the test comet. Material and methods. 15 cows, were taken with age between 3 and 4 years old, average weight of 350 kg, body condition between 3 and 3.5. Three experimental groups with five animals per group, which were exposed to the concentration of IVM to 1% to 3.15% more group control (without application of IVM were used. Animal blood sample was performed by venipuncture jugular or medial flow with vacutainer® needle, extracting 8 ml of blood. The blood samples it was collected at 9, 18 and 27 days post-treatment. Results. The display of the comets is made by using fluorescence microscope, the cells were evaluated by means of visual log and the Comet image software. Evidenced the presence of nuclei with DNA migration in all analyzed plates. The values of classification of comets indicate cells with high levels of damage (grade 3: cells with high damage. The rate of DNA damage of the treatment to 1% to 3.15% was significant, to relate to the control group. Conclusions. The results obtained in this study demonstrate the likely genotoxic potential of the use of IVM in cattle.

  10. The protective effect of hypoxia and dithiothreitol on X-ray-induced genetic damage in Arabidopsis

    International Nuclear Information System (INIS)

    Sree Ramulu, K.; Veen, J.H. van der

    1987-01-01

    A study was made on the protective effect of hypoxia and dithiothreitol (DTT) on X-ray-induced ovule sterility and embryonic lethality in Arabidopsis. Both hypoxia and DTT gave a pronounced and additive reduction of radiation-induced genetic damage. The reduction was significantly higher for ovule sterility than for embryonic lethals. It is suggested that non-fertilized ovules contain a higher ratio of strand breaks/other damage than embryonic lethals do, for hypoxia and DTT are known specifically to give a reduction of strand breaks. (Auth.)

  11. Interaction of bullets with intermediate targets: material transfer and damage.

    Science.gov (United States)

    Vermeij, Erwin; Rijnders, Marco; Pieper, Pascal; Hermsen, Rob

    2012-11-30

    In complex shooting incidents, it is not always clear which bullet hit or eventually killed the victim and who fired it. The examination of traces of foreign material embedded in or adhered to bullets provides critical information in the trajectory reconstruction of spent bullets. Such a reconstruction can have considerable legal implications because it can prove that it was not someone's intention to kill. However, the microtraces that remain on spent bullets are often ignored. Microtraces on bullets, around bullet-holes and on ricochet marks were investigated using SEM/EDX for two different types of bullets: a relatively hard, full metal jacket (FMJ) bullet and a relatively soft, lead round-nose (LRN) bullet. A total of 179 bullets were fired into intermediate targets, sheets of 5 different materials (MDF, greenboard, gypsum fibreboard, glass and steel), at approximate incident angles of 90°, 10° and 5°. Of the 144 bullets fired at incident angles of 90°, 130 bullets perforated one of the materials, and 14 bullets perforated two of the materials. The 35 bullets fired at incident angles of 10° and 5° ricocheted off the intermediate targets, producing ricochet marks. In the majority of cases, traces from the target materials were found on the bullet, both after perforation and ricochet. The only exceptions were (1) the perforation of 9-mm sheets of MDF by FMJ bullets and (2) ricochet off glass when the glass did not break. Steel targets transfer small, but still detectable traces of iron to the bullet. The order in which targets are hit was reflected in the traces found on the bullets, i.e., materials from a secondary target were deposited on top of deposits from the primary target. This result implies that it is possible to determine the order of impact from the stratification of the material analysed. Traces from the bullets were found around all the bullet holes. Wipe-off from lead bullets is sometimes visible by the naked eye. Ricocheting bullets produce

  12. Multi-Physics Computational Modeling Tool for Materials Damage Assessment, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovation proposed here is to provide a multi-physics modeling tool for materials damage assessment for application to future aircraft design. The software...

  13. Radiation damage in diagnostic window materials for the TFTR

    Energy Technology Data Exchange (ETDEWEB)

    Primak, W.

    1981-07-01

    The general problem of evaluating diagnostic window materials for the TFTR at the tank wall location is described. Specific evaluations are presented for several materials: vitreous silica, crystal quartz, sapphire, zinc selenide, and several fluorides: lithium fluoride, magnesium fluoride, and calcium fluoride; and seal glasses are discussed. The effects of the neutrons will be minimal. The major problems arise from the high flux of ionizing radiation, mainly the soft x rays which are absorbed near the surface of the materials. Additionally, this large energy deposition causes a significant thermal pulse with attendant thermal stresses. It is thus desirable to protect the windows with cover slips where this is feasible or to reduce the incident radiation by mounting the windows on long pipes. A more detailed summary is given at the end of this report.

  14. Preparation of the Jaws Damaged Parts from Composite Biopolymers Materials

    Directory of Open Access Journals (Sweden)

    Riyam A. Al-husseini

    2017-10-01

    Full Text Available Composite materials composing of fusing two materials or more are disaccorded in mechanical and physical characteristics, The studied the effect of changing in the reinforcement percentage by Hydroxyapatite Prepared nano world via the size of the nanoscale powder manufacturing manner chemical precipitation and microwave powders were two types their preparations have been from natural sources: the first type of eggshells and the other from the bones of fish in mechanical Properties which include the tensile strength, elastic modulus, elongation, hardness and tear for composite material consisting of Silicone rubber (SIR reinforced by (µ-n-HA, after strengthening silicone rubber Protect proportions (5,10,15,20 wt% of Article achieved results that increase the additive lead to increased hardness while tougher and modulus of elasticity decreases with added as shown in the diagrams.

  15. Fast neutron Damage Studies on NdFeB Materials

    OpenAIRE

    Anderson, S.; Spencer, J.; Wolf, Z.; Boussoufi, M.; Baldwin, A.; Pellett, D.; Volk, J.

    2005-01-01

    Many materials and electronics need to be tested for the radiation environment expected at linear colliders (LC) since both accelerator and detectors will be subjected to large fluences of hadrons, leptons and gamma’s over the life of the facility. While the linacs will be superconducting, there are still many uses for NdFeB in the damping rings, injection and extraction lines and final focus. Our understanding of the situation for rare earth, permanent magnet materials was presented at the P...

  16. Cumulative genetic damage in children exposed to preconception and intrauterine radiation

    International Nuclear Information System (INIS)

    Bross, I.D.; Natarajan, N.

    1980-01-01

    Using a mathematical model and newly developed computer software, the data from the Tri-State Leukemia Survey involving different combinations of radiation exposures to the father and mother prior to conception and to the mother during pregnancy were analyzed. The hypothesis that radiation exposure produces genetic damage which may be expressed in the child both as indicator disease and as leukemia was tested. The genetic damage was estimated in terms of the proportion affected by a given exposure. The relative risk of leukemia and certain other indicator diseases among those affected could then be estimated. The results show that there are at least two distinguishable risk groups, one group with lower (one or two exposures); and the other group with higher (two or three) radiation exposures

  17. The Adaptive Significance of Natural Genetic Variation in the DNA Damage Response of Drosophila melanogaster.

    Science.gov (United States)

    Svetec, Nicolas; Cridland, Julie M; Zhao, Li; Begun, David J

    2016-03-01

    Despite decades of work, our understanding of the distribution of fitness effects of segregating genetic variants in natural populations remains largely incomplete. One form of selection that can maintain genetic variation is spatially varying selection, such as that leading to latitudinal clines. While the introduction of population genomic approaches to understanding spatially varying selection has generated much excitement, little successful effort has been devoted to moving beyond genome scans for selection to experimental analysis of the relevant biology and the development of experimentally motivated hypotheses regarding the agents of selection; it remains an interesting question as to whether the vast majority of population genomic work will lead to satisfying biological insights. Here, motivated by population genomic results, we investigate how spatially varying selection in the genetic model system, Drosophila melanogaster, has led to genetic differences between populations in several components of the DNA damage response. UVB incidence, which is negatively correlated with latitude, is an important agent of DNA damage. We show that sensitivity of early embryos to UVB exposure is strongly correlated with latitude such that low latitude populations show much lower sensitivity to UVB. We then show that lines with lower embryo UVB sensitivity also exhibit increased capacity for repair of damaged sperm DNA by the oocyte. A comparison of the early embryo transcriptome in high and low latitude embryos provides evidence that one mechanism of adaptive DNA repair differences between populations is the greater abundance of DNA repair transcripts in the eggs of low latitude females. Finally, we use population genomic comparisons of high and low latitude samples to reveal evidence that multiple components of the DNA damage response and both coding and non-coding variation likely contribute to adaptive differences in DNA repair between populations.

  18. Fusion reactor materials program plan. Section 2. Damage analysis and fundamental studies

    International Nuclear Information System (INIS)

    1978-07-01

    The scope of this program includes: (1) Development of procedures for characterizing neutron environments of test facilities and fusion reactors, (2) Theoretical and experimental investigations of the influence of irradiation environment on damage production, damage microstructure evolution, and mechanical and physical property changes, (3) Identification and, where appropriate, development of essential nuclear and materials data, and (4) Development of a methodology, based on damage mechanisms, for correlating the mechanical behavior of materials exposed to diverse test environments and projecting this behavior to magnetic fusion reactor (MFR) environments. Some major problem areas are addressed

  19. A frictional contact problem with wear involving elastic-viscoplastic materials with damage and thermal effects

    Directory of Open Access Journals (Sweden)

    Abdelmoumene Djabi

    2015-05-01

    Full Text Available We consider a mathematical problem for quasistatic contact between a thermo-elastic-viscoplastic body with damage and an obstacle. The contact is frictional and bilateral with a moving rigid foundation which results in the wear of the contacting surface. We employ the thermo-elasticviscoplastic with damage constitutive law for the material. The damage of the material caused by elastic deformations. The evolution of the damage is described by an inclusion of parabolic type. The problem is formulated as a coupled system of an elliptic variational inequality for the displacement, a parabolic variational inequality for the damage and the heat equation for the temperature. We establish a variational formulation for the model and we prove the existence of a unique weak solution to the problem. The proof is based on a classical existence and uniqueness result on parabolic inequalities, differential equations and fixed point arguments.

  20. Ion beam-induced luminescence as method of characterization of radiation damage in polycrystalline materials

    Energy Technology Data Exchange (ETDEWEB)

    Jozwik, Iwona, E-mail: iwona.jozwik@itme.edu.pl [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland); Jagielski, Jacek [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland); National Centre for Nuclear Research, Soltana 7, 05-400 Otwock/Swierk (Poland); Gawlik, Grzegorz [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland); Panczer, Gerard [Institut Lumière Matière ILM, UMR5306 Université Lyon 1-CNRS, Université de Lyon, Villeurbanne (France); Moncoffre, Nathalie [Institut de Physique Nucléaire de Lyon IPNL, Université de Lyon, Université Lyon 1, CNRS/IN2P3, UMR 5822, Villeurbanne (France); Ratajczak, Renata [National Centre for Nuclear Research, Soltana 7, 05-400 Otwock/Swierk (Poland); Jozwik, Przemyslaw [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland); National Centre for Nuclear Research, Soltana 7, 05-400 Otwock/Swierk (Poland); Wajler, Anna; Sidorowicz, Agata [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland); Thomé, Lionel [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, CNRS/IN2P3, Universite Paris-Sud, Bat. 108, F-91405 Orsay (France)

    2015-12-15

    The problem of information about damage build-up, intensively studied for single crystals, poses many difficulties for polycrystalline materials. The Rutherford Backscattering/Channeling (RBS/C) technique could be applied for single crystals only, but its use is excluded in polycrystalline materials. Therefore the development of a quantitative method well suited for the evaluation of damage level in polycrystalline materials is a must, and still constitutes a major challenge in materials analysis. A comparative study of damage accumulation in magnesium aluminate spinel (MgAl{sub 2}O{sub 4}) has been conducted using ionoluminescence (IL) and RBS/C techniques. The results obtained by both methods, demonstrate a two-step character of damage build-up process. The values of the cross-section on the damage creation in each case were estimated using MSDA model. The results presented here confirm the huge potential of the luminescence techniques for damage analysis in single- and polycrystalline samples, and ability of the IL method to perform fast, in situ analysis of damage accumulation process.

  1. Radiation damage of the construction materials, Phase I, Part I- Radiation damage of the construction steels

    International Nuclear Information System (INIS)

    Lazarevic, Dj.

    1962-10-01

    The objective of this task was testing the mechanical properties of stainless steels having different grain size. Being an important material used mainly for reactor vessel construction stainless steel will be exposed to neutron flux in the RA reactor for testing

  2. Fast Neutron Damage Studies on NdFeB Materials

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, S.; Spencer, J.; Wolf, Z.; /SLAC; Baldwin, A.; Pellett, D.; Boussoufi, M.; /UC, Davis

    2005-05-17

    Many materials and electronics need to be tested for the radiation environment expected at linear colliders (LC) since both accelerator and detectors will be subjected to large fluences of hadrons, leptons and {gamma}'s over the life of the facility [1]. While the linacs will be superconducting, there are still many uses for NdFeB in the damping rings, injection and extraction lines and final focus. Our understanding of the situation for rare earth, permanent magnet materials was presented at PAC03 [2]. Our first measurements of fast neutron, stepped doses at the UC Davis McClellan Nuclear Reactor Center (UCD MNRC) were presented at EPAC04 [3]. We have extended the doses, included other manufacturer's samples, and measured induced radioactivities which are discussed in detail.

  3. Alpha damage in non-reference waste form matrix materials

    International Nuclear Information System (INIS)

    Burnay, S.G.

    1987-05-01

    Although bitumen is the matrix material currently used for European α-bearing intermediate level waste streams, polymer and polymer-modified cement matrices could have advantages over bitumen for such wastes. Two organic matrix systems have been studied - an epoxide resin, and an epoxide modified cement. Alpha irradiations were carried out by incorporating 241 Am at approx. 0.9 Ci/l. Comparisons have been made with unirradiated material and with materials which had been γ-irradiated to the same dose as the α-irradiated samples. Measurements were made of dimensional changes, mechanical properties and the leaching behaviour of 241 Am and 137 Cs. A limited amount of swelling (< 3%) was observed in α-irradiated epoxide resin; none was observed in the epoxide modified cement. Gamma irradiation to 300 kGy has no significant effect on the mechanical properties of either system. However, alpha irradiation to the same dose produced significant changes in flexural strength, an increase for the polymer and a decrease for the polymer-cement. Leaching in these systems was found to be a diffusion-controlled process; alpha irradiation to approx. 250 kGy has little effect on the leaching behaviour of either system. (author)

  4. Genetic damages in radiation workers of radiology centers in Bushehr port

    Directory of Open Access Journals (Sweden)

    Gholamreza Khamisipour

    2004-09-01

    Full Text Available Unstable genetic aberrations might provide a good marker for assessing genetic damage in populations exposed to low levels of ionizing radiation.The frequency of these aberrations was estimated in peripheral lymphocytes from hospital workers in Bushehr Port, occupationally exposed to low levels of ionizing radiation (54 subjects and age and sex matched controls. A total of 34 (23 males & 11 females subjects had unstable genetic aberrations (50 chromosomal-type & 31 chromatid type but only 7 subjects in control group had unstable genetic aberrations. When compared with controls, exposed workers showed a significant increase in structural chromosomal-type aberrations (p<0.001 OR=11 chromosomal exchange being the most frequent alteration. Chromatid deletion (18 cases and ring chromosome (4 cases were seen only in exposed group. There was no association between smoking status, sex, age, level of education or working years. The increased frequencies of chromosomal damage in radiation workers, indicate conducting cytogenetic analysis in parallel to physical dosimetry in the working place.

  5. Genetic and environmental influences on oxidative damage assessed in elderly Danish twins

    DEFF Research Database (Denmark)

    Broedbaek, Kasper; Ribel-Madsen, Rasmus; Henriksen, Trine

    2011-01-01

    Previous studies have shown an association between oxidative stress and various diseases in humans including cancer, cardiovascular disease, diabetes, and chronic respiratory disease. To what extents this damage is determined by genetic and environmental factors is unknown. In a classical twin...... study with 198 elderly twins we examined the contributions of genetic versus environmental factors to nucleic acid oxidation and lipid peroxidation. Urinary excretion of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), 8-oxo-7,8-dihydroguanosine (8-oxoGuo), and dinor,dihydro F2-isoprostane metabolites (F2......-IsoP-M) was measured using liquid chromatography-tandem mass spectrometry. The environmental influence on nucleic acid oxidation and lipid peroxidation was predominant, leaving only little influence from genetic factors, as evidenced by no differences in intraclass correlations between monozygotic (MZ...

  6. Preserving Yeast Genetic Heritage through DNA Damage Checkpoint Regulation and Telomere Maintenance

    Directory of Open Access Journals (Sweden)

    Huilin Zhou

    2012-10-01

    Full Text Available In order to preserve genome integrity, extrinsic or intrinsic DNA damages must be repaired before they accumulate in cells and trigger other mutations and genome rearrangements. Eukaryotic cells are able to respond to different genotoxic stresses as well as to single DNA double strand breaks (DSBs, suggesting highly sensitive and robust mechanisms to detect lesions that trigger a signal transduction cascade which, in turn, controls the DNA damage response (DDR. Furthermore, cells must be able to distinguish natural chromosomal ends from DNA DSBs in order to prevent inappropriate checkpoint activation, DDR and chromosomal rearrangements. Since the original discovery of RAD9, the first DNA damage checkpoint gene identified in Saccharomyces cerevisiae, many genes that have a role in this pathway have been identified, including MRC1, MEC3, RAD24, RAD53, DUN1, MEC1 and TEL1. Extensive studies have established most of the genetic basis of the DNA damage checkpoint and uncovered its different functions in cell cycle regulation, DNA replication and repair, and telomere maintenance. However, major questions concerning the regulation and functions of the DNA damage checkpoint remain to be answered. First, how is the checkpoint activity coupled to DNA replication and repair? Second, how do cells distinguish natural chromosome ends from deleterious DNA DSBs? In this review we will examine primarily studies performed using Saccharomyces cerevisiae as a model system.

  7. Processing of hazardous material, or damage treatment method for shallow layer underground storage structure

    International Nuclear Information System (INIS)

    Ito, Hiroshi; Sakaguchi, Takehiko; Nishioka, Yoshihiro.

    1997-01-01

    In radioactive waste processing facilities and shallow layer underground structures for processing hazardous materials, sheet piles having freezing pipes at the joint portions are spiked into soils at the periphery of a damaged portion of the shallow layer underground structure for processing or storing hazardous materials. Liquid nitrogen is injected to the freezing pipes to freeze the joint portions of adjacent sheet piles. With such procedures, continuous waterproof walls are formed surrounding the soils at the peripheries of the damaged portion. Further, freezing pipes are disposed in the surrounding soils, and liquid nitrogen is injected to freeze the soils. The frozen soils are removed, and artificial foundation materials are filled in the space except for the peripheries of the damaged portion after the removal thereof, and liquid suspension is filled in the peripheries of the damaged portion, and restoration steps for closing the damaged portion are applied. Then, the peripheries of the damaged portion are buried again. With such procedures, series of treatments for removing contaminated soils and repairing a damaged portion can be conducted efficiently at a low cost. (T.M.)

  8. Determining the Radiation Damage Effect on Glovebox Glove Material.

    Energy Technology Data Exchange (ETDEWEB)

    Cournoyer, M. E. (Michael E.); Balkey, J. J. (James J.); Andrade, R.M. (Rose M.)

    2005-01-01

    The Nuclear Material Technology (NMT) Division has the largest inventory of glove box gloves at Los Alamos National Laboratory. The minimization of unplanned breaches in the glovebox, e.g., glove failures, is a primary concern in the daily operations in NMT Division facilities, including the Plutonium Facility (PF-4) at TA-55 and Chemical and Metallurgy Research (CMR) Facility. Glovebox gloves in these facilities are exposed to elevated temperatures and exceptionally aggressive radiation environments (particulate {sup 239}Pu and {sup 238}Pu). Predictive models are needed to estimate glovebox glove service lifetimes, i.e. change-out intervals. Towards this aim aging studies have been initiated that correlate changes in mechanical (physical) properties with degradation chemistry. This present work derives glovebox glove change intervals based on previously reported mechanical data of thermally aged hypalon glove samples. Specifications for 30 mil tri-layered hypalon/lead glovebox gloves (TLH) and 15 mil hypalon gloves (HYP) have already been established. The relevant mechanical properties are shown on Table 1. Tensile strength is defined as the maximum load applied in breaking a tensile test piece divided by the original cross-sectional area of the test piece (Also termed maximum stress and ultimate tensile stress). Ultimate elongation is the elongation at time of rupture (Also termed maximum strain). The specification for the tensile test and ultimate elongation are the minimum acceptable values. In addition, the ultimate elongation must not vary 20% from the original value. In order to establish a service lifetimes for glovebox gloves in a thermal environment, the mechanical properties of glovebox glove materials were studied.

  9. Compilation of radiation damage test data part III: materials used around high-energy accelerators

    CERN Document Server

    Beynel, P; Schönbacher, H; CERN. Geneva

    1982-01-01

    For pt.II see CERN report 79-08 (1979). This handbook gives the results of radiation damage tests on various engineering materials and components intended for installation in radiation areas of the CERN high-energy particle accelerators. It complements two previous volumes covering organic cable-insulating materials and thermoplastic and thermosetting resins.

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

    NARCIS (Netherlands)

    Gutiérrez, M.A.; Borst, R. de

    1999-01-01

    This study presents some recent results on damage evolution in quasi-brittle materials including stochastic imperfections. The material strength is described as a random field and coupled to the response. The most probable configurations of imperfections leading to failure are sought by means of an

  11. Handbook of damage mechanics nano to macro scale for materials and structures

    CERN Document Server

    2015-01-01

    This authoritative reference provides comprehensive coverage of the topics of damage and healing mechanics. Computational modeling of constitutive equations is provided as well as solved examples in engineering applications. A wide range of materials that engineers may encounter are covered, including metals, composites, ceramics, polymers, biomaterials, and nanomaterials. The internationally recognized team of contributors employ a consistent and systematic approach, offering readers a user-friendly reference that is ideal for frequent consultation. Handbook of Damage Mechanics: Nano to Macro Scale for Materials and Structures is ideal for graduate students and faculty, researchers, and professionals in the fields of Mechanical Engineering, Civil Engineering, Aerospace Engineering, Materials Science, and Engineering Mechanics.

  12. Damage characterization in engineering materials using a combination of optical, acoustic, and thermal techniques

    Science.gov (United States)

    Tragazikis, I. K.; Exarchos, D. A.; Dalla, P. T.; Matikas, T. E.

    2016-04-01

    This paper deals with the use of complimentary nondestructive methods for the evaluation of damage in engineering materials. The application of digital image correlation (DIC) to engineering materials is a useful tool for accurate, noncontact strain measurement. DIC is a 2D, full-field optical analysis technique based on gray-value digital images to measure deformation, vibration and strain a vast variety of materials. In addition, this technique can be applied from very small to large testing areas and can be used for various tests such as tensile, torsion and bending under static or dynamic loading. In this study, DIC results are benchmarked with other nondestructive techniques such as acoustic emission for damage localization and fracture mode evaluation, and IR thermography for stress field visualization and assessment. The combined use of these three nondestructive methods enables the characterization and classification of damage in materials and structures.

  13. Damage detection in laminar thermoplastic composite materials by means of embedded optical fibers

    Directory of Open Access Journals (Sweden)

    Kojović Aleksandar M.

    2006-01-01

    Full Text Available This paper investigates the possibility of applying optical fibers as sensors for investigating low energy impact damage in laminar thermoplastic composite materials, in real time. Impact toughness testing by a Charpy impact pendulum with different loads was conducted in order to determine the method for comparative measurement of the resulting damage in the material. For that purpose intensity-based optical fibers were built in to specimens of composite materials with Kevlar 129 (the DuPont registered trade-mark for poly(p-phenylene terephthalamide woven fabric as reinforcement and thermoplastic PVB (poly(vinyl butyral as the matrix. In some specimens part of the layers of Kevlar was replaced with metal mesh (50% or 33% of the layers. Experimental testing was conducted in order to observe and analyze the response of the material under multiple low-energy impacts. Light from the light-emitting diode (LED was launched to the embedded optical fiber and was propagated to the phototransistor-based photo detector. During each impact, the signal level, which is proportional to the light intensity in the optical fiber, drops and then slowly recovers. The obtained signals were analyzed to determine the appropriate method for real time damage monitoring. The major part of the damage occurs during impact. The damage reflects as a local, temporary release of strain in the optical fiber and an increase of the signal level. The obtained results show that intensity-based optical fibers could be used for measuring the damage in laminar thermoplastic composite materials. The acquired optical fiber signals depend on the type of material, but the same set of rules (relatively different, depending on the type of material could be specified. Using real time measurement of the signal during impact and appropriate analysis enables quantitative evaluation of the impact damage in the material. Existing methods in most cases use just the intensity of the signal before

  14. Radiation Damage Studies of Materials and Electronic Devices Using Hadrons

    Energy Technology Data Exchange (ETDEWEB)

    Pellett, David; Baldwin, Andrew; Gallagher, Garratt; Olson, David; Styczinski, Marshall

    2014-05-14

    We have irradiated NdFeB permanent magnet samples from different manufacturers and with differing values of coercivity and remanence using stepped doses of 1 MeV equivalent neutrons up to a fluence of 0:64 1015n=cm2 to evaluate effects on magnetization and B field distributions. The samples with high coercivity, irradiated in open circuit configurations, showed no or minimal effects when compared with unirradiated samples, whereas the lower coercivity magnets suffered significant losses of magnetization and changes in the shapes of their field patterns. One such magnet underwent a fractional magnetization loss of 13.1% after a fluence of 0:59 1015 n=cm2. This demagnetization was not uniform. With increasing fluence, B field scans along the centerlines of the pole faces revealed that the normal component of B decreased more near the midpoint of the scan than near the ends. In addition, a fit to the curve of overall magnetization loss with fluence showed a significant deviation from linearity. The results are discussed in light of other measurements and theory. The high coercivity materials appear suitable for use in accelerator applications subject to irradiation by fast neutrons such as dipoles where the internal demagnetizing field is comparable to or less than that of the open circuit samples tested in this study.

  15. Optical fiber sensors for damage analysis in aerospace materials

    Science.gov (United States)

    Schindler, Paul; May, Russell; Claus, Richard

    1995-01-01

    Under this grant, fiber optic sensors were investigated for use in the nondestructive evaluation of aging aircraft. Specifically, optical fiber sensors for detection and location of impacts on a surface, and for detection of corrosion in metals were developed. The use of neural networks was investigated for determining impact location by processing the output of a network of fiberoptic strain sensors distributed on a surface. This approach employs triangulation to determine location by comparing the arrival times at several sensors, of the acoustic signal generated by the impact. For this study, a neural network simulator running on a personal computer was used to train a network using a back-propagation algorithm. Fiber optic extrinsic Fabry-Perot interferometer (EFPI) strain sensors are attached to or embedded in the surface, so that stress waves emanating from an impact can be detected. The ability of the network to determine impact location by time-or-arrival of acoustic signals was assessed by comparing network outputs with actual experimental results using impacts on a panel instrumented with optical fiber sensors. Using the neural network to process the sensor outputs, the impact location can be inferred to centimeter range accuracy directly from the arrival time data. In addition, the network can be trained to determine impact location, regardless of material anisotropy. Results demonstrate that a back-propagation network identifies impact location for an anisotropic graphite/bismaleimide plate with the same accuracy as that for an isotropic aluminum plate. Two different approaches were investigated for the development of fiber optic sensors for corrosion detection in metals, both utilizing optical fiber sensors with metal coatings. In the first approach, an extrinsic Fabry-Perot interferometric fiber optic strain sensor was placed under tensile stress, and while in the resulting strained position, a thick coating of metal was applied. Due to an increase in

  16. Impacts of damage production and accumulation on materials performance in irradiation environment

    DEFF Research Database (Denmark)

    Singh, B.N.

    1998-01-01

    Aspects of generation of atomic displacements and surviving defect fractions and their sensitivity to recoil energy have been considered. These considerations show that the nature of the primary damage production plays a vital role in the evolution of the damage accumulation as well as mechanical...... the damage accumulation, irradiation hardening and the loss of ductility. The recently developed production bias model together with one-dimensional glide of interstitial clusters produced in the cascades has been shown to describe the damage accumulation at temperatures above stage V for pure metals...... and needs to be extended to temperatures below stage V and to materials of practical interests. This requires, however, that the information regarding the effects of alloying elements and impurity atoms on the nature of the primary damage state are available from molecular dynamics and kinetic Monte Carlo...

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

    Science.gov (United States)

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

    1992-02-01

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

  18. Elevated oxidative membrane damage associated with genetic modifiers of Lyst-mutant phenotypes.

    Directory of Open Access Journals (Sweden)

    Colleen M Trantow

    2010-07-01

    Full Text Available LYST is a large cytosolic protein that influences the biogenesis of lysosome-related organelles, and mutation of the encoding gene, LYST, can cause Chediak-Higashi syndrome. Recently, Lyst-mutant mice were recognized to also exhibit an iris disease resembling exfoliation syndrome, a common cause of glaucoma in humans. Here, Lyst-mutant iris phenotypes were used in a search for genes that influence Lyst pathways. In a candidate gene-driven approach, albino Lyst-mutant mice homozygous for a mutation in Tyr, whose product is key to melanin synthesis within melanosomes, exhibited complete rescue of Lyst-mutant iris phenotypes. In a genetic background-driven approach using a DBA/2J strain of congenic mice, an interval containing Tyrp1 enhanced Lyst-dependent iris phenotypes. Thus, both experimental approaches implicated the melanosome, an organelle that is a potential source of oxidative stress, as contributing to the disease phenotype. Confirming an association with oxidative damage, Lyst mutation resulted in genetic context-sensitive changes in iris lipid hydroperoxide levels, being lowest in albino and highest in DBA/2J mice. Surprisingly, the DBA/2J genetic background also exposed a late-onset neurodegenerative phenotype involving cerebellar Purkinje-cell degeneration. These results identify an association between oxidative damage to lipid membranes and the severity of Lyst-mutant phenotypes, revealing a new mechanism that contributes to pathophysiology involving LYST.

  19. On a possible methodology for identifying the initiation of damage of a class of polymeric materials

    Science.gov (United States)

    Alagappan, P.; Kannan, K.; Rajagopal, K. R.

    2016-08-01

    In this paper, we provide a possible methodology for identifying the initiation of damage in a class of polymeric solids. Unlike most approaches to damage that introduce a damage parameter, which might be a scalar, vector or tensor, that depends on the stress or strain (that requires knowledge of an appropriate reference configuration in which the body was stress free and/or without any strain), we exploit knowledge of the fact that damage is invariably a consequence of the inhomogeneity of the body that makes the body locally `weak' and the fact that the material properties of a body invariably depend on the density, among other variables that can be defined in the current configuration, of the body. This allows us to use density, for a class of polymeric materials, as a means to identify incipient damage in the body. The calculations that are carried out for the biaxial stretch of an inhomogeneous multi-network polymeric solid bears out the appropriateness of the thesis that the density of the body can be used to forecast the occurrence of damage, with the predictions of the theory agreeing well with experimental results. The study also suggests a meaningful damage criterion for the class of bodies being considered.

  20. Upgrading of highly elapsed degradation damage evaluation of structural materials for the light water reactors

    International Nuclear Information System (INIS)

    Katada, Yasuyuki; Matsushima, Shinobu; Sato, Shunji

    1998-01-01

    In this study, for degradation of structural materials in accompanying with highly yearly lapse of the nuclear power plants, it was an aim to elucidate interaction between material degradation and degradation under high hot water environment. And, another aims consisted in intention of expansion protection and recovery evaluation of damage due to laser processing method and so on for welded portion showing extreme material degradation and in preparation of damage region diagram based on the obtained data. In this fiscal year, on interaction between materials and environmental degradation, it was found that as stress corrosion cracking of materials hardened by shot peening shows a resemble shapes of stress-strain curve in CERT and CLRT, shapes of load-time curve were much different. On comparison of the SP material and non-processing material, as peak current showing activity of newly created surface shows no difference, re-passivation of the SP material was found to be too late. And, on recovery evaluation of material degradation damage, as it was found that constant melt depth was essential to evaluate corrosion, a condition preparation aimed for melt depth of more than 1 mm. As only small amount of bubbles were observed at molten metal part on YAG laser processing, it was found that many small bubbles scatter at thermal effect part. (G.K.)

  1. Maritime Transport of Environmentally Damaging Materials - A Balance Between Absolute Freedom and Strict Prohibition

    Directory of Open Access Journals (Sweden)

    Thaqal S. Al-Ajmi

    2007-06-01

    Full Text Available This study is intended to balance the rights of free navigation in all of its forms whether in the high seas or in the territorial waters of other States by resorting to the right of innocent passage and right of transit passage, which is enjoyable by all States and the obligation to protect the environment from any damaging materials as imposed upon all States at the same time, when such damaging materials are shipped from one State to another via seas or oceans. According to this study, which presented many evidence from international law and regional and even national practice, the obligation to protect the environment supersedes the right of free navigation, therefore restricting the right to ship or transport materials that could cause damage to the environment.

  2. Materials damaging and rupture - Volumes 1-2. General remarks, metallic materials. Non-metallic materials and biomaterials, assemblies and industrial problems

    International Nuclear Information System (INIS)

    Clavel, M.; Bompard, P.

    2009-01-01

    The rupture and damaging of materials and structures is almost always and unwanted events which may have catastrophic consequences. Even if the mechanical failure causes can often be analyzed using a thorough knowledge of materials behaviour, the forecasting and prevention of failures remain difficult. While the macroscopic mechanical behaviour is often the result of average effects at the structure or microstructure scale, the damage is very often the result of the combination of load peaks, of localization effects and of microstructure defects. This book, presented in two volumes, takes stock of the state-of-the-art of the knowledge gained in the understanding and modelling of rupture and damaging phenomena of materials and structure, mostly of metallic type. It gives an outline of the available knowledge for other classes of materials (ceramics, biomaterials, geo-materials..) and for different types of applications (aeronautics, nuclear industry). Finally, it examines the delicate problem, but very important in practice, of the behaviour of assemblies. Content: Vol.1 - physical mechanisms of materials damaging and rupture; rupture mechanics; cyclic plasticity and fatigue crack growth; fatigue crack propagation; environment-induced cracking; contacts and surfaces. Vol.2 - glasses and ceramics; natural environments: soils and rocks; mechanical behaviour of biological solid materials: the human bone; contribution of simulation to the understanding of rupture mechanisms; assemblies damaging and rupture; industrial cases (behaviour of PWR pressure vessel steels, and thermal and mechanical stresses in turbojet engines). (J.S.)

  3. Optimal filter design with progressive genetic algorithm for local damage detection in rolling bearings

    Science.gov (United States)

    Wodecki, Jacek; Michalak, Anna; Zimroz, Radoslaw

    2018-03-01

    Harsh industrial conditions present in underground mining cause a lot of difficulties for local damage detection in heavy-duty machinery. For vibration signals one of the most intuitive approaches of obtaining signal with expected properties, such as clearly visible informative features, is prefiltration with appropriately prepared filter. Design of such filter is very broad field of research on its own. In this paper authors propose a novel approach to dedicated optimal filter design using progressive genetic algorithm. Presented method is fully data-driven and requires no prior knowledge of the signal. It has been tested against a set of real and simulated data. Effectiveness of operation has been proven for both healthy and damaged case. Termination criterion for evolution process was developed, and diagnostic decision making feature has been proposed for final result determinance.

  4. Action of the chlorophyllin before genetic damage induced by gamma radiation in germinal cells of Drosophila

    International Nuclear Information System (INIS)

    Moreno B, R.

    2004-01-01

    The chlorophyllin (CHLN) is a porphyrin of nutritious grade and soluble in water, derived of the chlorophyll. It has been reported that this pigment is a good anti mutagen since it reduces the damage to the DNA caused by physical or chemical agents of direct or indirect action. Their anti carcinogenic action has also been demonstrated when it is administered itself during the induced post-initiation phase by aflatoxins and heterocyclic amines. However in the last decade it has been reported that it also has promoter activity against the genetic damage induced by diverse agents like the alkyl ants of direct and indirect action, the gamma radiation and some heterocyclic amines. This effect has been observed in testing systems like Salmonella, Drosophila, rainbow trout and rodents. In the mouse spermatogonia it has been reported that it reduces the damage to the DNA but with the test of lethal dominant in Drosophila increment the damage induced by gamma radiation. The present study consisted on evaluating the effect of the CHLN in the line germinal masculine of Drosophila by means of the lethal recessive test bound to the sex (LRLS) with the stump Muller 5 and a litters system. Its were pretreated wild males with CHLN and 24 h later were irradiated with 0, 10, 20 and 40 Gy of gamma radiation immediately later were crossed with virgin females of the stump Basc and at 72 h the male was transferred to a cultivation media with three new virgin females, this process repeated three times until completing 3 litters. The F1 it was crossed among itself and in the F2 it was analysed the presence or absence of lethals. The results indicated that the CHLN per se incremented the basal frequency of damage due to the pigment can act as an agent that is inserted to the ADN causing pre mutagenic leisure. Nevertheless with the groups treated with the different doses of gamma radiation the CHLN does not present any protector action, neither promoter except in the litter I of the group

  5. Effect of cadmium on genetic toxicity and protection of cortex acanthopanasia radicis against genetic damage induced by cadmium

    International Nuclear Information System (INIS)

    Liu Bing; Pang Huimin; Chen Minyi

    1999-01-01

    Objective and Methods: The test of sperm aberration and micronucleus of bone marrow cells in mice were used to detect the mutagenicity of cadmium and anti-mutagenicity of Cortex Acanthopanasia Radicis (CAR) on germ cell and somatic cell. Kunming mice were divided randomly into four groups: normal saline control group (NS): MMC control group (MMC 1.0 mg/kg); Cd-mutate group (1/5 LD 50 ), 17.6 mg/kg); CAR anti-mutate group (CAR 1,2,4 g/kg + Cd). Ridit test and x 2 were used to evaluate the statistical significance of the date. Results: The experiment demonstrated that Chinese medicine CAR can significantly decrease sperm aberration and micronuclei frequencies induced by Cd (P<0.01). Conclusion: As an anti-mutagen CAR has practical value in occupational protection against genetic damage induced by Cd

  6. Review of Repair Materials for Fire-Damaged Reinforced Concrete Structures

    Science.gov (United States)

    Zahid, MZA Mohd; Abu Bakar, BH; Nazri, FM; Ahmad, MM; Muhamad, K.

    2018-03-01

    Reinforced concrete (RC) structures perform well during fire and may be repaired after the fire incident because their low heat conductivity prevents the loss or degradation of mechanical strength of the concrete core and internal reinforcing steel. When an RC structure is heated to more than 500 °C, mechanical properties such as compressive strength, stiffness, and tensile strength start to degrade and deformations occur. Although the fire-exposed RC structure shows no visible damage, its residual strength decreases compared with that in the pre-fire state. Upon thorough assessment, the fire-damaged RC structure can be repaired or strengthened, instead of subjecting to partial or total demolition followed by reconstruction. The structure can be repaired using several materials, such as carbon fiber-reinforced polymer, glass fiber-reinforced polymer, normal strength concrete, fiber-reinforced concrete, ferrocement, epoxy resin mortar, and high-performance concrete. Selecting an appropriate repair material that must be compatible with the substrate or base material is a vital step to ensure successful repair. This paper reviews existing repair materials and factors affecting their performance. Of the materials considered, ultra-high-performance fiber-reinforced concrete (UHPFRC) exhibits huge potential for repairing fire-damaged RC structures but lack of information available. Hence, further studies must be performed to assess the potential of UHPFRC in rehabilitating fire-damaged RC structures.

  7. Enhancement of global flood damage assessments using building material based vulnerability curves

    Science.gov (United States)

    Englhardt, Johanna; de Ruiter, Marleen; de Moel, Hans; Aerts, Jeroen

    2017-04-01

    This study discusses the development of an enhanced approach for flood damage and risk assessments using vulnerability curves that are based on building material information. The approach draws upon common practices in earthquake vulnerability assessments, and is an alternative for land-use or building occupancy approach in flood risk assessment models. The approach is of particular importance for studies where there is a large variation in building material, such as large scale studies or studies in developing countries. A case study of Ethiopia is used to demonstrate the impact of the different methodological approaches on direct damage assessments due to flooding. Generally, flood damage assessments use damage curves for different land-use or occupancy types (i.e. urban or residential and commercial classes). However, these categories do not necessarily relate directly to vulnerability of damage by flood waters. For this, the construction type and building material may be more important, as is used in earthquake risk assessments. For this study, we use building material classification data of the PAGER1 project to define new building material based vulnerability classes for flood damage. This approach will be compared to the widely applied land-use based vulnerability curves such as used by De Moel et al. (2011). The case of Ethiopia demonstrates and compares the feasibility of this novel flood vulnerability method on a country level which holds the potential to be scaled up to a global level. The study shows that flood vulnerability based on building material also allows for better differentiation between flood damage in urban and rural settings, opening doors to better link to poverty studies when such exposure data is available. Furthermore, this new approach paves the road to the enhancement of multi-risk assessments as the method enables the comparison of vulnerability across different natural hazard types that also use material-based vulnerability curves

  8. Wear and damage of articular cartilage with friction against orthopedic implant materials.

    Science.gov (United States)

    Oungoulian, Sevan R; Durney, Krista M; Jones, Brian K; Ahmad, Christopher S; Hung, Clark T; Ateshian, Gerard A

    2015-07-16

    The objective of this study was to measure the wear response of immature bovine articular cartilage tested against glass or alloys used in hemiarthroplasties. Two cobalt chromium alloys and a stainless steel alloy were selected for these investigations. The surface roughness of one of the cobalt chromium alloys was also varied within the range considered acceptable by regulatory agencies. Cartilage disks were tested in a configuration that promoted loss of interstitial fluid pressurization to accelerate conditions believed to occur in hemiarthroplasties. Results showed that considerably more damage occurred in cartilage samples tested against stainless steel (10 nm roughness) and low carbon cobalt chromium alloy (27 nm roughness) compared to glass (10 nm) and smoother low or high carbon cobalt chromium (10 nm). The two materials producing the greatest damage also exhibited higher equilibrium friction coefficients. Cartilage damage occurred primarily in the form of delamination at the interface between the superficial tangential zone and the transitional middle zone, with much less evidence of abrasive wear at the articular surface. These results suggest that cartilage damage from frictional loading occurs as a result of subsurface fatigue failure leading to the delamination. Surface chemistry and surface roughness of implant materials can have a significant influence on tissue damage, even when using materials and roughness values that satisfy regulatory requirements. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Wear and Damage of Articular Cartilage with Friction Against Orthopaedic Implant Materials

    Science.gov (United States)

    Oungoulian, Sevan R.; Durney, Krista M.; Jones, Brian K.; Ahmad, Christopher S.; Hung, Clark T.; Ateshian, Gerard A.

    2015-01-01

    The objective of this study was to measure the wear response of immature bovine articular cartilage tested against glass or alloys used in hemiarthroplasties. Two cobalt chromium alloys and a stainless steel alloy were selected for these investigations. The surface roughness of one of the cobalt chromium alloys was also varied within the range considered acceptable by regulatory agencies. Cartilage disks were tested in a configuration that promoted loss of interstitial fluid pressurization to accelerate conditions believed to occur in hemiarthroplasties. Results showed that considerably more damage occurred in cartilage samples tested against stainless steel (10 nm roughness) and low carbon cobalt chromium alloy (27 nm roughness) compared to glass (10 nm) and smoother low or high carbon cobalt chromium (10 nm). The two materials producing the greatest damage also exhibited higher equilibrium friction coefficients. Cartilage damage occurred primarily in the form of delamination at the interface between the superficial tangential zone and the transitional middle zone, with much less evidence of abrasive wear at the articular surface. These results suggest that cartilage damage from frictional loading occurs as a result of subsurface fatigue failure leading to the delamination. Surface chemistry and surface roughness of implant materials can have a significant influence on tissue damage, even when using materials and roughness values that satisfy regulatory requirements. PMID:25912663

  10. The effects of butylated hydroxytoluene on radiation and chemically-induced genetic damage in Drosophila melanogaster

    International Nuclear Information System (INIS)

    Sankaranarayanan, K.

    1983-01-01

    This paper reports the results of a study on the effects of the phenolic antioxidant butylated hydroxytoluene (BHT) on the sensitivity of Drosophila germ cells to the X-ray and chemical induction of genetic damage. Prior to irradiation or chemical treatment, the flies were raised in normal, BHT-containing or dimethyl sulphoxide (DMSO)-containing media. In one series of X-ray experiments, male pupae raised in these different media were irradiated. The concentration of BHT in the medium was 0.05% (in 0.5% DMSO) and that of DMSO, 0.5%. In the X-ray experiments, the frequencies of sex-linked recessive lethals and of autosomal translocations in spermatids of males raised in the BHT-containing medium were significantly lower than in those of males raised in the other two media. If however, the spermatids in pupae were irradiated, the amounts of genetic damage in the three groups of males were nearly the same. (orig./WB)

  11. Effects of ion beam irradiation on size of mutant sector and genetic damage in Arabidopsis

    Energy Technology Data Exchange (ETDEWEB)

    Hase, Yoshihiro, E-mail: hase.yoshihiro@qst.go.jp [Takasaki Advanced Radiation Research Institute, National Institutes for Quantum and Radiological Science and Technology (QST), 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Nozawa, Shigeki [Takasaki Advanced Radiation Research Institute, National Institutes for Quantum and Radiological Science and Technology (QST), 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Narumi, Issay [Faculty of Life Sciences, Toyo University, 1-1-1 Izumino, Itakura, Gunma 374-0193 (Japan); Oono, Yutaka [Takasaki Advanced Radiation Research Institute, National Institutes for Quantum and Radiological Science and Technology (QST), 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)

    2017-01-15

    Size of mutant sector and genetic damage were evaluated in Arabidopsis to further our understanding of effective ion beam use in plant mutation breeding. Arabidopsis seeds, heterozygous for the GLABRA1 (GL1) gene (GL1/gl1-1), were irradiated with 15.8 MeV/u neon ions (mean linear energy transfer (LET): 352 keV/μm), 17.3 MeV/u carbon ions (113 keV/μm), or {sup 60}Co gamma rays. The frequency and size of glabrous sectors generated because of inactivation of the GL1 allele were examined. The frequency and overall size of large deletions were evaluated based on the loss of heterozygosity of DNA markers using DNA isolated from glabrous tissue. Irrespective of the radiation properties, plants with mutant sectors were obtained at similar frequencies at the same effective dosage necessary for survival reduction. Ion beams tended to induce larger mutant sectors than gamma rays. The frequency of large deletions (>several kbp) increased as the LET value increased, with chromosome regions larger than 100 kbp lost in most large deletions. The distorted segregation ratio of glabrous plants in the progenies of irradiated GL1/gl1-1 plants suggested frequent occurrence of chromosome rearrangement, especially those subjected to neon ions. Exposure to ion beams with moderate LET values (30–110 keV/μm) is thought effective for inducing mutant sectors without causing extensive genetic damage.

  12. Status of radiation damage dosimetry for fusion materials testing in reactors

    International Nuclear Information System (INIS)

    Alberman, A.; Dierckx, R.; Nolthenius, H.J.; Voorbraak, W.P.

    1992-04-01

    The EURATOM Working Group on Reactor Dosimetry (EWGRD) has issued in the past several documents in order to establish standardized procedures and recommendations on neutron spectrum information, fluence measurements, damage cross-section data, etc. The main goal of this status report is to review the suitable material irradiation characterization parameters, in such a way that experimental results, obtained in a research reactor environment, can be applied in the design of the fusion power plants. Recent developments in fusion reactor technology programs and mainly the large European component qualification tests undertaken for NET (Next European Torus) have led the EWGRD to consider new requirements. Particularly the application of ceramics (tritium breeding blankets, insulators) addresses new requirements: damage to sublattices, relevance of 'dpa' as irradiation parameter, etc. This report presents the status of available metrology methods, recommended cross-sections and damage assessment, relevant to fusion technology material irradiations. (author). 42 refs.; 2 figs.; 2 tabs

  13. Radiation damage formation in fusion structural materials due to elastic and inelastic processes

    Science.gov (United States)

    Ryazanov, A. I.; Semenov, E. V.

    2011-10-01

    A new theoretical model based on Boltzmann transport equation for moving displaced atoms is developed for the investigations of main important characteristics of radiation damage production in fusion structural materials. The main characteristics sub-cascades are determined here including the distribution of sub-cascades per PKA, average number of point defects per sub-cascade combining suggested model and NRT approach, sub-cascade's cross-sections and generation rates for both elastic and inelastic processes. On the basis of this developed model the numerical calculations for the main important characteristics of radiation damage production, cascade and sub-cascade formations in different fusion structural materials such as Fe, V, C, Al, Be and W are performed using the neutron energy spectra for fusion reactors: ITER and DEMO. For the comparison of difference in radiation damage production in fusion and fission reactors the additional numerical calculations have been made for neutron energy spectrum in fast atomic reactor HFIR.

  14. Modeling of Stress Development During Thermal Damage Healing in Fiber-reinforced Composite Materials Containing Embedded Shape Memory Alloy Wires

    NARCIS (Netherlands)

    Bor, Teunis Cornelis; Warnet, Laurent; Akkerman, Remko; de Boer, Andries

    2010-01-01

    Fiber-reinforced composite materials are susceptible to damage development through matrix cracking and delamination. This article concerns the use of shape memory alloy (SMA) wires embedded in a composite material to support healing of damage through a local heat treatment. The composite material

  15. A VIABLE CAPACITIVE APPROACH FOR DAMAGE DETECTION OF AIRCRAFT COMPOSITE MATERIAL

    OpenAIRE

    Ensheng, Dong; Yilin, Jiang; Wei, Guo; Xiangbin, Yu

    2013-01-01

    Military and Commercial aircraft are being constructed by more and more advanced composite materials. In order to prevent catastrophic failure any damage in aircraft composite material should be detected as soon as possible. The relations of the electrode length, the electrode width, and the space between electrodes to the testing sensitivity of the uniplanar double electrodes are investigated. A three dimensions model of the uniplanar capacitive sensor with 8 electrodes is founded and the op...

  16. The use of recombinant DNA techniques to study radiation-induced damage, repair and genetic change in mammalian cells

    International Nuclear Information System (INIS)

    Thacker, J.

    1986-01-01

    A brief introduction is given to appropriate elements of recombinant DNA techniques and applications to problems in radiobiology are reviewed with illustrative detail. Examples are included of studies with both 254 nm ultraviolet light and ionizing radiation and the review progresses from the molecular analysis of DNA damage in vitro through to the nature of consequent cellular responses. The review is dealt with under the following headings: Molecular distribution of DNA damage, The use of DNA-mediated gene transfer to assess damage and repair, The DNA double strand break: use of restriction endonucleases to model radiation damage, Identification and cloning of DNA repair genes, Analysis of radiation-induced genetic change. (UK)

  17. A Robust Damage Reporting Strategy for Polymeric Materials Enabled by Aggregation Induced Emission

    Science.gov (United States)

    2016-08-17

    Spearing, S. M.; Soutis, C. Damage Detection in Composite Materials Using Lamb Wave Methods. Smart Mater. Struct. 2002, 11, 269. (2) Bruns, N.; Pustelny... Transporting Property. J. Mater. Chem. 2012, 22, 4527−4534. (22) Banal, J. L.; White, J. M.; Lam, T. W.; Blakers, A. W.; Ghiggino, K. P.; Wong, W. W. H. A

  18. Cyclic Plastic Response and Damage in Materials for High Temperature Applications

    Czech Academy of Sciences Publication Activity Database

    Polák, Jaroslav; Obrtlík, Karel; Petrenec, Martin

    2014-01-01

    Roč. 46, č. 5 (2014), s. 601-607 ISSN 0039-2316 R&D Projects: GA ČR(CZ) GA13-23652S Institutional support: RVO:68081723 Keywords : fatigue damage * cyclic plastic * high temperature * crack initiation Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 0.376, year: 2014

  19. Status of neutron dosimetry and damage analysis for the fusion materials program

    International Nuclear Information System (INIS)

    Greenwood, L.R.

    1979-01-01

    The status of neutron flux and spectral measurements is described for fusion material irradiations at reactor, T(d,n), Be(d,n), and spallation neutron sources. Such measurements are required for the characterization of an irradiation in terms of displacement damage, gas and transmutant production. Emphasis is placed on nuclear data deficiencies with specific recommendations for cross section measurements and calculations

  20. High dose radiation damage in nuclear energy structural materials investigated by heavy ion irradiation simulation

    International Nuclear Information System (INIS)

    Zheng Yongnan; Xu Yongjun; Yuan Daqing

    2014-01-01

    Structural materials in ITER, ADS and fast reactor suffer high dose irradiations of neutrons and/or protons, that leads to severe displacement damage up to lOO dpa per year. Investigation of radiation damage induced by such a high dose irradiation has attracted great attention along with the development of nuclear energy facilities of new generation. However, it is deeply hampered for the lacking of high dose neutron and proton sources. Irradiation simulation of heavy ions produced by accelerators opens up an effective way for laboratory investigation of high dose irradiation induced radiation damage encountered in the ITER, ADS, etc. Radiation damage is caused mainly by atomic displacement in materials. The displacement rate of heavy ions is about lO 3 ∼10 7 orders higher than those of neutrons and protons. High displacement rate of heavy ions significantly reduces the irradiation time. The heavy ion irradiation simulation technique (HIIS) technique has been developed at China Institute of Atomic Energy and a series of the HIIS experiments have been performed to investigate radiation damage in stainless steels, tungsten and tantalum at irradiation temperatures from room temperature to 800 ℃ and in the irradiation dose region up to 100 dpa. The experimental results show that he radiation swelling peak for the modified stainless steel appears in the temperature region around 580 ℃ and the radiation damage is more sensitive to the temperature, the size of the radiation induced vacancy cluster or void increase with the increasing of the irradiation dose, and among the three materials the home-made modified stainless steel has the best radiation resistant property. (authors)

  1. A Comparative Study on Damage Mechanism of Sandwich Structures with Different Core Materials under Lightning Strikes

    Directory of Open Access Journals (Sweden)

    Jiangyan Yan

    2017-10-01

    Full Text Available Wind turbine blades are easily struck by lightning, a phenomenon that has attracted more and more attention in recent years. On this subject a large current experiment was conducted on three typical blade sandwich structures to simulate the natural lightning-induced arc effects. The resulting damage to different composite materials has been compared: polyvinyl chloride (PVC and polyethylene terephthalate (PET suffered pyrolysis and cracks inside, while the damage to balsa wood was fibers breaking off and large delamination between it and the resin layer, and only a little chemical pyrolysis. To analyze the damage mechanism on sandwich structures of different materials, a finite element method (FEM model to calculate the temperature and pressure distribution was built, taking into consideration heat transfer and flow expansion due to impulse currents. According to the simulation results, PVC had the most severe temperature and pressure distribution, while PET and balsa wood were in the better condition after the experiments. The temperature distribution results explained clearly why balsa wood suffered much less chemical pyrolysis than PVC. Since balsa wood had better thermal stability than PET, the pyrolysis area of PET was obviously larger than that of balsa wood too. Increasing the volume fraction of solid components of porous materials can efficiently decrease the heat transfer velocity in porous materials. Permeability didn’t influence that much. The findings provide support for optimum material selection and design in blade manufacturing.

  2. Evaluation of fatigue damage of pressure vessel materials by observation of microstructures

    International Nuclear Information System (INIS)

    Yoshida, Kazuo

    1994-01-01

    As the important factor as the secular change mode of pressure vessel materials, there is fatigue damage. In USA, there is the move to use LWRs by extending their life, and it becomes necessary to show the soundness of the structures of machinery and equipment for long period. For exactly evaluating the soundness of the structures of machinery and equipment, it is important to clarify the degree of secular deterioration of the materials. In this report, by limiting to the fatigue damage of LWR pressure vessel steel, the method of grasping the change of microstructure and the method of estimating the degree of fatigue damage from the change of microstructure are shown. The change of microstructure arising in materials due to fatigue advances in the following steps, namely, the multiplication of dislocations, the tangling of dislocations, the formation of cell structure, the turning of cells, the formation of microcracks, the growth of cracks and fracture. In the case of pressure vessel steel, due to the quenching and tempering, the cell structure is formed from the beginning, and the advance of fatigue is recognized as the increase of the turning angle of cell structures. The detection of fatigue damage by microstructure is reported. (K.I.)

  3. Axisymmetric thermoviscoelastoplastic state of thin laminated shells made of a damageable material

    Science.gov (United States)

    Galishin, A. Z.

    2008-04-01

    A technique for the determination of the axisymmetric thermoviscoelastoplastic state of laminated thin shells made of a damageable material is developed. The technique is based on the kinematic equations of the theory of thin shells that account for transverse shear strains. The thermoviscoplastic equations, which describe the deformation of a shell element along paths of small curvature, are used as the constitutive equations. The equivalent stress that appears in the kinetic equations of damage and creep is determined from a failure criterion that accounts for the stress mode. The thermoviscoplastic deformation of a two-layer shell that models an element of a rocket engine nozzle is considered as an example

  4. Finite-Element Modeling of a Damaged Pipeline Repaired Using the Wrap of a Composite Material

    Science.gov (United States)

    Lyapin, A. A.; Chebakov, M. I.; Dumitrescu, A.; Zecheru, G.

    2015-07-01

    The nonlinear static problem of FEM modeling of a damaged pipeline repaired by a composite material and subjected to internal pressure is considered. The calculation is carried out using plasticity theory for the pipeline material and considering the polymeric filler and the composite wrap. The level of stresses in various zones of the structure is analyzed. The most widespread alloy used for oil pipelines is selected as pipe material. The contribution of each component of the pipeline-filler-wrap system to the level of stresses is investigated. The effect of the number of composite wrap layers is estimated. The results obtained allow one to decrease the costs needed for producing test specimens.

  5. Elasto-plastic damage analysis of functionally graded material disks subjected to thermal shock and thermal cycle

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae-Myung; Toi, Yutaka [Tokyo Univ. (Japan). Inst. of Industrial Science

    2001-03-01

    The elasto-plastic damage behaviors of functionally graded materials (FGM) subjected to thermal loading are analyzed by the finite element method using continuum damage mechanics. The Lemaitre's damage model is employed to analyze the damage behavior of a FGM disk subjected to thermal shock and a FGM coating subjected to thermal cycle. The effect of FGM on the thermal damage is discussed through some numerical examples for industrial materials. Numerical results show the validity of the present method for the evaluation and the development of new FGM. (author)

  6. SANITY OF CORN GRAINS AS A FUNCTION OF GENETIC MATERIAL

    Directory of Open Access Journals (Sweden)

    L. F. Oliveira

    2018-02-01

    Full Text Available Diseases that occur in corn crops can cause great losses to farmers and consumers of its product and derivatives. So, was evaluated the sanity of maize grains in different genetic materials. The grains used were obtained from the crop of 2014/2015 on a farm in the city of Sorriso, State of Mato Grosso. For this, grain samples were collected from hybrids P3630H, 30F53YH, P2830H, and P3844H. The standard test ("Blotter Test" allowed noticing the incidence of Aspergillus sp., Fusarium sp. and Penicillium sp. Data were submitted to analysis of variance and Scott-Knott test at 5% probability. In treatments with the resistant genetic material the genus with the highest incidence was Penicillium sp. (82%, followed by Fusarium sp. (68.75% and Aspergillus sp. (15.25%. The hybrid with the lower incidence of Fusarium sp. was P2830H (59%. The hybrid with greater resistance to Aspergillus sp. and Penicillium sp. was P3844H (5 and 55%, respectively. The most susceptible hybrid to pathogens Aspergillus sp., Fusarium sp. and Penicillium sp. was 30F53YH (37, 79 and 94%, respectively. For the better sanitary quality of grains, based on the observed data, it is recommended to use the hybrid P2830H

  7. ANALYTICAL MODEL OF DAMAGED AIRCRAFT SKIN BONDED REPAIRS ASSUMING THE MATERIAL PROPERTIES DEGRADATION

    Directory of Open Access Journals (Sweden)

    2016-01-01

    Full Text Available The search of optimal variants for composite repair patches allows to increase the service life of a damaged air- plane structure. To sensibly choose the way of repair, it is necessary to have a computational complex to predict the stress- strain condition of "structure-adhesive-patch" system and to take into account the damage growth considering the material properties change. The variant of the computational complex based on inclusion method is proposed.For calculation purposes the repair bonded joint is divided into two areas: a metal plate with patch-shaped hole and a "patch-adhesive layer-skin" composite plate (inclusion.Calculation stages:Evaluation of the patch influence to the skin stress-strain condition, stress distribution between skin and patch in the case of no damage. Calculation of the stress-strain condition is performed separately for the skin with hole and for the inclusion; solutions are coupled based on strain compatibility.Definition of the damage growth parameters at new stress-strain condition due to bonded patch existence. Skincrack stress intensity factors are found to identify the crack growth velocity. Patch is modelled as a set of "springs" bridging the crack.Degradation analysis of elasticity properties for the patch material.Repair effectiveness is evaluated with respect to crack growth velocity reduction in the initial material in compari- son with the case of the patch absence.Calculation example for the crack repair effectiveness depending on number of loading cycles for the 7075-T6 aluminum skin is given. Repair patches are carbon-epoxy, glass-epoxy and boron-epoxy material systems with quasi- isotropic layup and GLARE hybrid metal-polymeric material.The analysis shows the high effectiveness of the carbon-epoxy patch. Due to low stiffness, the glass-epoxy patchdemonstrates the least effectiveness. GLARE patch containing the fiberglass plies oriented across the crack has the same effectiveness as the carbon and

  8. Compression fatigue of Wind Turbine Blade composites materials and damage mechanisms

    DEFF Research Database (Denmark)

    Fraisse, Anthony; Brøndsted, Povl

    driven edgewise bending introduces significant fully reversed cycling at the leading and trailing edges. Therefore, material manufacturer and WTB manufacturer demand test results of highest reliability and reproducibility. However, these equirements for compression-compression and tensioncompression...... laminate architectures have been tested in order to validate the test method. Damage mechanisms and damage progression in compression fatigue have been investigated using 3D X-Ray Tomography and a qualitative explanation of the damage mechanisms is presented....... fatigue properties are a big challenge for the test institutes to meet. Tests are very difficult to perform, as it is nearly impossible to design an optimal test setup. This study shows a newly developed sample geometry and test method in order to obtain representative and reliable results. Two different...

  9. Acoustic Research on the Damage Mechanism of Carbon Fiber Composite Materials

    Science.gov (United States)

    Wang, Bing; Liu, Yanlei; Sheng, Shuiping

    This thesis involves the study about different processes including the tensile fracture, inter-layer tear or avulsion, as well as the interlaminar shear or split regarding carbon fiber composite materials with the aid of acoustic emission technique. Also, various acoustic emission signals that are released by composite samples in the process of fracture are analyzed. As is indicated by the test results, different acoustic emissive signals that are released by carbon fiber layers in various stages of damage and fracture bear different characteristics. Acoustic detection can effectively monitor the whole stage of elastic deformation, the damage development, and even the accumulation process while figuring out in an efficient manner about the internal activities of the composites, plus the diverse types of damages. In addition, its fabulous application value lies in its relevant structural evaluation as well as the evaluation of integrity with regard to carbon fiber composite.

  10. Glutathione S-Transferase Gene Polymorphisms: Modulator of Genetic Damage in Gasoline Pump Workers.

    Science.gov (United States)

    Priya, Kanu; Yadav, Anita; Kumar, Neeraj; Gulati, Sachin; Aggarwal, Neeraj; Gupta, Ranjan

    2015-01-01

    This study investigated genetic damage in gasoline pump workers using the cytokinesis blocked micronucleus (CBMN) assay. Blood and urine samples were collected from 50 gasoline pump workers and 50 control participants matched with respect to age and other confounding factors except for exposure to benzene through gasoline vapors. To determine the benzene exposure, phenol was analyzed in urinary samples of exposed and control participants. Urinary mean phenol level was found to be significantly high (P gasoline pump workers (6.70 ± 1.78) when compared to control individuals (2.20 ± 0.63; P gasoline vapors can increase genotoxic risk in gasoline pump workers. © The Author(s) 2015.

  11. Influence of XRCC1 Genetic Polymorphisms on Ionizing Radiation-Induced DNA Damage and Repair

    Directory of Open Access Journals (Sweden)

    Silvia Sterpone

    2010-01-01

    Full Text Available It is well known that ionizing radiation (IR can damage DNA through a direct action, producing single- and double-strand breaks on DNA double helix, as well as an indirect effect by generating oxygen reactive species in the cells. Mammals have evolved several and distinct DNA repair pathways in order to maintain genomic stability and avoid tumour cell transformation. This review reports important data showing a huge interindividual variability on sensitivity to IR and in susceptibility to developing cancer; this variability is principally represented by genetic polymorphisms, that is, DNA repair gene polymorphisms. In particular we have focussed on single nucleotide polymorphisms (SNPs of XRCC1, a gene that encodes for a scaffold protein involved basically in Base Excision Repair (BER. In this paper we have reported and presented recent studies that show an influence of XRCC1 variants on DNA repair capacity and susceptibility to breast cancer.

  12. Development of Nondestructive Non-Contact Acousto-Thermal Evaluation Technique for Damage Detection in Materials (Postprint)

    Science.gov (United States)

    2012-09-01

    used to demonstrate the capability of the NCATS technique to evaluate incipient thermal damage in composite structures. An aluminum alloy aircraft wheel...extensive damage that can be detected visually without much difficulty. When the damage is not visible, ultrasonic and thermography NDE techniques have...AFRL-RX-WP-JA-2014-0223 DEVELOPMENT OF NONDESTRUCTIVE NON- CONTACT ACOUSTO-THERMAL EVALUATION TECHNIQUE FOR DAMAGE DETECTION IN MATERIALS

  13. FEATURES of NON-DESTRUCTIVE damage CONTROL OF aircraft parts made of composite MATERIALS at the enterprises of aviation industry

    Directory of Open Access Journals (Sweden)

    A. V. Kopylov

    2014-01-01

    Full Text Available The article describes the urgent problems which can arise at enterprises of aviation industries by the operating air during non-destructive damage control of products made of composite materials used in aircraft. The methods of control are very specific due to have a number of peculiarities in detecting damages in view of the complicated composite materials structure.

  14. Potential Damage to Modern Building Materials from 21st Century Air Pollution

    Directory of Open Access Journals (Sweden)

    Peter Brimblecombe

    2010-01-01

    Full Text Available The evolution of damage to building materials has been estimated for the 21st century, with a particular focus on aluminum, zinc, copper, plastic, paint, and rubber in urban areas. We set idealized air pollution and climates to represent London and Prague across the period 1950–2100. Environmental parameters were used to estimate future recession, corrosion, and loss of properties through published damage or dose-response functions. The 21st century seems to provide a less aggressive environment for stone and metals than recent times. Improvements in air quality are the most relevant drivers for this amelioration. Changes in climate predicted for the 21st century do not alter this picture. On the other hand, polymeric materials, plastic, paint, and rubber might show slightly increased rates of degradation, to some extent the result of enhanced oxidant concentrations, but also the possibility of contributions from more solar radiation.

  15. Atomistic modeling of nanowires, small-scale fatigue damage in cast magnesium, and materials for MEMS

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, Martin L. [Univ. of Colorado, Boulder, CO (United States); Talmage, Mellisa J. [Univ. of Colorado, Boulder, CO (United States); McDowell, David L. [Georgia Inst. of Technology, Atlanta, GA (United States); West, Neil [Univ. of Colorado, Boulder, CO (United States); Gullett, Philip Michael [Mississippi State Univ., Mississippi State, MS (United States); Miller, David C. [Univ. of Colorado, Boulder, CO (United States); Spark, Kevin [Univ. of Colorado, Boulder, CO (United States); Diao, Jiankuai [Univ. of Colorado, Boulder, CO (United States); Horstemeyer, Mark F. [Mississippi State Univ., Mississippi State, MS (United States); Zimmerman, Jonathan A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gall, K. [Georgia Inst. of Technology, Atlanta, GA (United States)

    2006-10-01

    Lightweight and miniaturized weapon systems are driving the use of new materials in design such as microscale materials and ultra low-density metallic materials. Reliable design of future weapon components and systems demands a thorough understanding of the deformation modes in these materials that comprise the components and a robust methodology to predict their performance during service or storage. Traditional continuum models of material deformation and failure are not easily extended to these new materials unless microstructural characteristics are included in the formulation. For example, in LIGA Ni and Al-Si thin films, the physical size is on the order of microns, a scale approaching key microstructural features. For a new potential structural material, cast Mg offers a high stiffness-to-weight ratio, but the microstructural heterogeneity at various scales requires a structure-property continuum model. Processes occurring at the nanoscale and microscale develop certain structures that drive material behavior. The objective of the work presented in this report was to understand material characteristics in relation to mechanical properties at the nanoscale and microscale in these promising new material systems. Research was conducted primarily at the University of Colorado at Boulder to employ tightly coupled experimentation and simulation to study damage at various material size scales under monotonic and cyclic loading conditions. Experimental characterization of nano/micro damage will be accomplished by novel techniques such as in-situ environmental scanning electron microscopy (ESEM), 1 MeV transmission electron microscopy (TEM), and atomic force microscopy (AFM). New simulations to support experimental efforts will include modified embedded atom method (MEAM) atomistic simulations at the nanoscale and single crystal micromechanical finite element simulations. This report summarizes the major research and development accomplishments for the LDRD project

  16. Damage of ductile plastic materials in nuclear development of an industrial numerical tool

    International Nuclear Information System (INIS)

    Strub, C.; Felix, S.

    1993-01-01

    To study how harmful a defect (crack...) in a structure can be, an analysis based on the concept of local approach is well suited. A rheological model has been implemented in the CASTEM 2000 finite element code, for elastoplastic materials with isotropic hardening and damage characteristics. This simulation allows a good description of a ductile rupture test on a notched sample. (A.B.). 3 refs,. 8 figs

  17. A Multidisciplinary Approach to Health Monitoring and Materials Damage Prognosis for Metallic Aerospace Systems

    Science.gov (United States)

    2013-03-01

    material model to identify the hotspot of the structural component in ABAQUS . The meso RVE mesh generated using the software OOF has been used at...joint was analyzed in ABAQUS . The same cyclic loading condition which was used during the fatigue test, that is, 490 N (110 lbs) to 4900 N (1100 lbs...damage model. The main advantage of this approach is that no baseline training data is required and signals can be classified on the fly to new

  18. Group constant preparation for the estimate of neutron induced damage in structural materials

    International Nuclear Information System (INIS)

    Panini, G.C.

    1996-01-01

    Neutron heating (kerma), displacement per atom cross sections (DPA), gas and γ-ray production are important parameters for the estimate of the damage produced by neutron induced nuclear reactions in the structural materials. The NJOY System for Nuclear Data Processing has been extensively used in order to compute the above quantities; here the theory, the algorithms and the connected problems are described. (author). 6 refs, 3 tabs

  19. Frost induced damages within porous materials - from concrete technology to fuel cells technique

    Science.gov (United States)

    Palecki, Susanne; Gorelkov, Stanislav; Wartmann, Jens; Heinzel, Angelika

    2017-12-01

    Porous media like concrete or layers of membrane electrode assemblies (MEA) within fuel cells are affected by a cyclic frost exposure due to different damage mechanisms which could lead to essential degradation of the material. In general, frost damages can only occur in case of a specific material moisture content. In fuel cells, residual water is generally available after shut down inside the membrane i.e. the gas diffusion layer (GDL). During subsequent freezing, this could cause various damage phenomena such as frost heaves and delamination effects of the membrane electrode assembly, which depends on the location of pore water and on the pore structure itself. Porous materials possess a pore structure that could range over several orders of magnitudes with different properties and freezing behaviour of the pore water. Latter can be divided into macroscopic, structured and pre-structured water, influenced by surface interactions. Therefore below 0 °C different water modifications can coexist in a wide temperature range, so that during frost exposure a high amount of unfrozen and moveable water inside the pore system is still available. This induces transport mechanisms and shrinkage effects. The physical basics are similar for porous media. While the freezing behaviour of concrete has been studied over decades of years, in order to enhance the durability, the know-how about the influence of a frost attack on fuel cell systems is not fully understood to date. On the basis of frost damage models for concrete structures, an approach to describe the impact of cyclic freezing and thawing on membrane electrode assemblies has been developed within this research work. Major aim is beyond a better understanding of the frost induced mechanisms, the standardization of a suitable test procedure for the assessment of different MEA materials under such kind of attack. Within this contribution first results will be introduced.

  20. Damage tolerant design and condition monitoring of composite material and bondlines in wind turbine blades: Failure and crack propagation

    DEFF Research Database (Denmark)

    Pereira, Gilmar Ferreira; Mikkelsen, Lars Pilgaard; McGugan, Malcolm

    2015-01-01

    This research presents a novel method to asses a crack growing/damage event in composite material, in polymer, or in structural adhesive using Fibre Bragg Grating (FBG) sensors embedded in the host material, and its application in to a composite material structure: Wind Turbine Trailing Edge....... A Structure-Material-Sensor Finite Element Method (FEM) model was developed to simulate the Fibre Bragg Grating sensor output response, when embedded in a host material (Composite material, polymer or adhesive), during a crack growing/damage event. This Structure-Material-Sensor model provides a tool...

  1. Effect of Projectile Materials on Foreign Object Damage of a Gas-Turbine Grade Silicon Nitride

    Science.gov (United States)

    Choi, Sung R.; Racz, Zsolt; Bhatt, Ramakrishna T.; Brewer, David N.; Gyekenyesi, John P.

    2005-01-01

    Foreign object damage (FOD) behavior of AS800 silicon nitride was determined using four different projectile materials at ambient temperature. The target test specimens rigidly supported were impacted at their centers by spherical projectiles with a diameter of 1.59 mm. Four different types of projectiles were used including hardened steel balls, annealed steel balls, silicon nitride balls, and brass balls. Post-impact strength of each target specimen impacted was determined as a function of impact velocity to better understand the severity of local impact damage. The critical impact velocity where target specimens fail upon impact was highest with brass balls, lowest with ceramic ball, and intermediate with annealed and hardened steel balls. Degree of strength degradation upon impact followed the same order as in the critical impact velocity with respect to projectile materials. For steel balls, hardened projectiles yielded more significant impact damage than annealed counterparts. The most important material parameter affecting FOD was identified as hardness of projectiles and was correlated in terms of critical impact velocity, impact deformation, and impact load.

  2. Numerical-graphical method for describing the creep of damaged highly filled polymer materials

    Science.gov (United States)

    Bykov, D. L.; Martynova, E. D.; Mel'nikov, V. P.

    2015-09-01

    A method for describing the creep behavior until fracture of a highly filled polymer material previously damaged in preliminary tests is proposed. The constitutive relations are the relations of nonlinear endochronic theory of aging viscoelastic materials (NETAVEM) [1]. The numerical-graphical method for identifying the functions occurring in NETAVEM, which was proposed in [2] for describing loading processes at a constant strain rate, is used here for the first time in creep theory. We use the results of experiments with undamaged and preliminary damaged specimens under the action of the same constant tensile loads. The creep kernel is determined in experiments with an undamaged specimen. The reduced time function contained in NETAVEM is determined from the position of points corresponding to the same values of strain on the creep curves of the damaged and undamaged specimens. An integral equation is solved to obtain the aging function, and then the viscosity function is determined. The knowledge of all functions contained in the constitutive relations permits solving the creep problem for products manufactured from a highly filled polymer material.

  3. Ice crystallization in porous building materials: assessing damage using real-time 3D monitoring

    Science.gov (United States)

    Deprez, Maxim; De Kock, Tim; De Schutter, Geert; Cnudde, Veerle

    2017-04-01

    Frost action is one of the main causes of deterioration of porous building materials in regions at middle to high latitudes. Damage will occur when the internal stresses due to ice formation become larger than the strength of the material. Hence, the sensitivity of the material to frost damage is partly defined by the structure of the solid body. On the other hand, the size, shape and interconnection of pores manages the water distribution in the building material and, therefore, the characteristics of the pore space control potential to form ice crystals (Ruedrich et al., 2011). In order to assess the damage to building materials by ice crystallization, lot of effort was put into identifying the mechanisms behind the stress build up. First of all, volumetric expansion of 9% (Hirschwald, 1908) during the transition of water to ice should be mentioned. Under natural circumstances, however, water saturation degrees within natural rocks or concrete cannot reach a damaging value. Therefore, linear growth pressure (Scherer, 1999), as well as several mechanisms triggered by water redistribution during freezing (Powers and Helmuth, 1953; Everett, 1961) are more likely responsible for damage due to freezing. Nevertheless, these theories are based on indirect observations and models and, thus, direct evidence that reveals the exact damage mechanism under certain conditions is still lacking. To obtain this proof, in-situ information needs to be acquired while a freezing process is performed. X-ray computed tomography has proven to be of great value in material research. Recent advances at the Ghent University Centre for Tomography (UGCT) have already allowed to dynamically 3D image crack growth in natural rock during freeze-thaw cycles (De Kock et al., 2015). A great potential to evaluate the different stress build-up mechanisms can be found in this imaging technique consequently. It is required to cover a range of materials with different petrophysical properties to achieve

  4. Insensitivity to Flaws Leads to Damage Tolerance in Brittle Architected Meta-Materials.

    Science.gov (United States)

    Montemayor, L C; Wong, W H; Zhang, Y-W; Greer, J R

    2016-02-03

    Cellular solids are instrumental in creating lightweight, strong, and damage-tolerant engineering materials. By extending feature size down to the nanoscale, we simultaneously exploit the architecture and material size effects to substantially enhance structural integrity of architected meta-materials. We discovered that hollow-tube alumina nanolattices with 3D kagome geometry that contained pre-fabricated flaws always failed at the same load as the pristine specimens when the ratio of notch length (a) to sample width (w) is no greater than 1/3, with no correlation between failure occurring at or away from the notch. Samples with (a/w) > 0.3, and notch length-to-unit cell size ratios of (a/l) > 5.2, failed at a lower peak loads because of the higher sample compliance when fewer unit cells span the intact region. Finite element simulations show that the failure is governed by purely tensile loading for (a/w) meta-materials may give rise to their damage tolerance and insensitivity of failure to the presence of flaws even when made entirely of intrinsically brittle materials.

  5. Formulation and computational aspects of plasticity and damage models with application to quasi-brittle materials

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z.; Schreyer, H.L. [New Mexico Engineering Research Institute, Albuquerque, NM (United States)

    1995-09-01

    The response of underground structures and transportation facilities under various external loadings and environments is critical for human safety as well as environmental protection. Since quasi-brittle materials such as concrete and rock are commonly used for underground construction, the constitutive modeling of these engineering materials, including post-limit behaviors, is one of the most important aspects in safety assessment. From experimental, theoretical, and computational points of view, this report considers the constitutive modeling of quasi-brittle materials in general and concentrates on concrete in particular. Based on the internal variable theory of thermodynamics, the general formulations of plasticity and damage models are given to simulate two distinct modes of microstructural changes, inelastic flow and degradation of material strength and stiffness, that identify the phenomenological nonlinear behaviors of quasi-brittle materials. The computational aspects of plasticity and damage models are explored with respect to their effects on structural analyses. Specific constitutive models are then developed in a systematic manner according to the degree of completeness. A comprehensive literature survey is made to provide the up-to-date information on prediction of structural failures, which can serve as a reference for future research.

  6. A Nonlocal Damage Model for Elastoplastic Materials based on Gradient Plasticity Theory

    International Nuclear Information System (INIS)

    Chen, J.; Yuan, H.; Kalkhof, D.

    2001-10-01

    Experimental and theoretical studies have shown that size effects in structure deformations and failure become significant as soon as strain gradients are high. For instance as soon as material failure dominates a deformation process, the specimen displays increasingly softening and the finite element computation is significantly affected by the element size. Without considering this effect in the constitutive model one cannot hope a reliable prediction to the ductile material failure process. To give an accurate prediction of the structure integrity and to quantify the material failure process, it is necessary to introduce the strain gradients into constitutive equations. Gradient plasticity models have been discussed extensively in recent years. The mesh-sensitivity in numerical analysis has been successfully eliminated and analytical explanations for size effects were given. In the present work, a general framework for a nonlocal micromechanical damage model based on the gradient-dependent plasticity theory is presented and its finite element algorithm for finite strains is developed and implemented. In the finite element algorithm, equivalent plastic strain and plastic multiplier have been taken as the unknown variables. Due to the implementation of the Lapacian term, the implicit C 1 shape function is applied for equivalent plastic strain and can be transformed to arbitrary quadrilateral elements. Computational analysis of material failure is consistent to the known size effects. By incorporating the Laplacian of plastic strain into the GTN constitutive relationship, the known mesh-dependence is overcome for the simulation of ductile damage processes and numerical results correlate uniquely with the given material parameters. In the chapters of applications, we discuss simulations of micro-indentation tests based on the gradient plasticity model. The role of intrinsic material length parameters in the gradient plasticity model is investigated. The

  7. Recognition of materials and damage on historical buildings using digital image classification

    Directory of Open Access Journals (Sweden)

    Jose E. Merono

    2015-01-01

    Full Text Available Nowadays, techniques in digital image processing make it possible to detect damage, such as moisture or biological changes, on the surfaces of historical buildings. Digital classification techniques can be used to identify damages in construction materials in a non-destructive way. In this study, we evaluate the application of the object-oriented classification technique using photographs taken with a Fujifilm IS-Pro digital single lens reflex camera and the integration of the classified images in a three-dimensional model obtained through terrestrial laser scanning data in order to detect and locate damage affecting biocalcarenite stone employed in the construction of the Santa Marina Church (Córdoba, Spain. The Fujifilm IS-Pro camera captures spectral information in an extra-visible range, generating a wide spectral image with wavelengths ranging from ultraviolet to infrared. Techniques of object-oriented classification were applied, taking into account the shapes, textures, background information and spectral information in the image. This type of classification requires prior segmentation, defined as the search for homogeneous regions in an image. The second step is the classification process of these regions based on examples. The output data were classified according to the kind of damage that affects the biocalcarenite stone, reaching an overall classification accuracy of 92% and an excellent kappa statistic (85.7%. We have shown that multispectral classification with visible and near-infrared bands increased the degree of recognition among different damages. Post-analysis of these data integrated in a three-dimensional model allows us to obtain thematic maps with the size and position of the damage.

  8. On the relationship between indentation hardness and modulus, and the damage resistance of biological materials.

    Science.gov (United States)

    Labonte, David; Lenz, Anne-Kristin; Oyen, Michelle L

    2017-07-15

    The remarkable mechanical performance of biological materials is based on intricate structure-function relationships. Nanoindentation has become the primary tool for characterising biological materials, as it allows to relate structural changes to variations in mechanical properties on small scales. However, the respective theoretical background and associated interpretation of the parameters measured via indentation derives largely from research on 'traditional' engineering materials such as metals or ceramics. Here, we discuss the functional relevance of indentation hardness in biological materials by presenting a meta-analysis of its relationship with indentation modulus. Across seven orders of magnitude, indentation hardness was directly proportional to indentation modulus. Using a lumped parameter model to deconvolute indentation hardness into components arising from reversible and irreversible deformation, we establish criteria which allow to interpret differences in indentation hardness across or within biological materials. The ratio between hardness and modulus arises as a key parameter, which is related to the ratio between irreversible and reversible deformation during indentation, the material's yield strength, and the resistance to irreversible deformation, a material property which represents the energy required to create a unit volume of purely irreversible deformation. Indentation hardness generally increases upon material dehydration, however to a larger extent than expected from accompanying changes in indentation modulus, indicating that water acts as a 'plasticiser'. A detailed discussion of the role of indentation hardness, modulus and toughness in damage control during sharp or blunt indentation yields comprehensive guidelines for a performance-based ranking of biological materials, and suggests that quasi-plastic deformation is a frequent yet poorly understood damage mode, highlighting an important area of future research. Instrumented

  9. Skin damage probabilities using fixation materials in high-energy photon beams

    International Nuclear Information System (INIS)

    Carl, J.; Vestergaard, A.

    2000-01-01

    Patient fixation, such as thermoplastic masks, carbon-fibre support plates and polystyrene bead vacuum cradles, is used to reproduce patient positioning in radiotherapy. Consequently low-density materials may be introduced in high-energy photon beams. The aim of the this study was to measure the increase in skin dose when low-density materials are present and calculate the radiobiological consequences in terms of probabilities of early and late skin damage. An experimental thin-windowed plane-parallel ion chamber was used. Skin doses were measured using various overlaying low-density fixation materials. A fixed geometry of a 10 x 10 cm field, a SSD = 100 cm and photon energies of 4, 6 and 10 MV on Varian Clinac 2100C accelerators were used for all measurements. Radiobiological consequences of introducing these materials into the high-energy photon beams were evaluated in terms of early and late damage of the skin based on the measured surface doses and the LQ-model. The experimental ion chamber save results consistent with other studies. A relationship between skin dose and material thickness in mg/cm 2 was established and used to calculate skin doses in scenarios assuming radiotherapy treatment with opposed fields. Conventional radiotherapy may apply mid-point doses up to 60-66 Gy in daily 2-Gy fractions opposed fields. Using thermoplastic fixation and high-energy photons as low as 4 MV do increase the dose to the skin considerably. However, using thermoplastic materials with thickness less than 100 mg/cm 2 skin doses are comparable with those produced by variation in source to skin distance, field size or blocking trays within clinical treatment set-ups. The use of polystyrene cradles and carbon-fibre materials with thickness less than 100 mg/cm 2 should be avoided at 4 MV at doses above 54-60 Gy. (author)

  10. New evaluation method of material degradation considering synergistic effects of radiation damage

    International Nuclear Information System (INIS)

    Miwa, Yukio; Kaji, Yoshiyuki; Okubo, Nariaki; Kondo, Keietsu; Tsukada, Takashi

    2008-01-01

    In core structural materials of next generation reactors such as a liquid-metal cooled fast breeding reactor and a supercritical-water cooled thermal or first reactor, materials' degradation behavior by neutron irradiation damage and thermal (cyclic) stress should be considered with fair accuracy in design process (including maintenance and repair plans), because the materials are used under higher temperature gradients and higher neutron flux fields than those in the present light water reactors. In the current experimental design rules, service lives of core structural components were determined by the materials degradation such as the increase of ductile-to-brittle transition temperature after post irradiation examination data. However, other materials degradations such as irradiation-assisted stress corrosion cracking (IASCC), which occurs by the degradation synergistically interacting with radiation hardening, local chemical composition change, swelling and radiation creep, should be considered reasonably in the design process of the next generation reactors, because of the anticipation of the beneficial effects by synergy of radiation damage. The radiation hardening and local chemical composition change at grain boundaries due to radiation-induced segregation increased with increasing dose. Above some threshold dose, swelling increased rapidly with increasing dose. Residual stress due to thermal stress and welding procedure decreased with increasing dose. To predict material failure by IASCC with reasonable accuracy, in this study, each material degradation phenomenon with different dose dependence was modeled with consideration of radiation induced stress relaxation. And then the models were integrated to simulate the failure behavior for the duration of reactor operation period. In this paper, the models obtained by ion-irradiation experiments and compared by data from neutron irradiation experiments were presented, and the concept of our new evaluation

  11. New ideas in dosimetry and damage calculations for fusion materials irradiations

    International Nuclear Information System (INIS)

    Greenwood, L.R.

    1986-01-01

    Nuclear data and techniques are being developed to improve our ability to characterize fusion materials irradiations in terms of neutron fluence and spectra as well as damage parameters such as atomic displacements, gas production, and other transmutation. The production of long-lived isotopes are being measured near 14 MeV, including reactions from Al, Fe, and Mo to 26 Al, 53 Mn, and 94 Nb, and measurements for other reactions are in progress. These data can be used for fusion reactor dosimetry, plasma diagnostics, and the estimation of radioactivity in fusion reactor materials. Dosimetry cross sections are being measured for fission reactors using Be(d,n) sources (E/sub d/= 7 to 40 MeV) and monoenergetic neutron sources from 1 to 14 MeV. These data can be used to adjust activation cross sections. Spallation cross sections are being measured for higher-energy accelerator neutron sources. Helium production cross sections are being tested at all fusion irradiation facilities. We have recently discovered a new thermal helium production in copper, similar to the well-known effect in nickel. Recommended procedures have been published for the calculation of helium from both copper and nickel in mixed-spectrum reactors. A new program SPECOMP has recently been developed to calculate displacement damage for compounds. This program uses the SPECTER recoil atom distributions and integrates over secondary displacement functions for each combination of incident ion and matrix material to determine displacement cross sections for alloys, insulators, and breeder materials

  12. Spatially distributed damage detection in CMC thermal protection materials using thin-film piezoelectric sensors

    Science.gov (United States)

    Kuhr, Samuel J.; Blackshire, James L.; Na, Jeong K.

    2009-03-01

    Thermal protection systems (TPS) of aerospace vehicles are subjected to impacts during in-flight use and vehicle refurbishment. The damage resulting from such impacts can produce localized regions that are unable to resist extreme temperatures. Therefore it is essential to have a reliable method to detect, locate, and quantify the damage occurring from such impacts. The objective of this research is to demonstrate a capability that could lead to detecting, locating and quantifying impact events for ceramic matrix composite (CMC) wrapped tile TPS via sensors embedded in the TPS material. Previous research had shown a correlation between impact energies, material damage state, and polyvinylidene fluoride (PVDF) sensor response for impact energies between 0.07 - 1.00 Joules, where impact events were located directly over the sensor positions1. In this effort, the effectiveness of a sensor array is evaluated for detecting and locating low energy impacts on a CMC wrapped TPS. The sensor array, which is adhered to the internal surface of the TPS tile, is used to detect low energy impact events that occur at different locations. The analysis includes an evaluation of signal amplitude levels, time-of-flight measurements, and signal frequency content. Multiple impacts are performed at each location to study the repeatability of each measurement.

  13. A Damage Resistance Comparison Between Candidate Polymer Matrix Composite Feedline Materials

    Science.gov (United States)

    Nettles, A. T

    2000-01-01

    As part of NASAs focused technology programs for future reusable launch vehicles, a task is underway to study the feasibility of using the polymer matrix composite feedlines instead of metal ones on propulsion systems. This is desirable to reduce weight and manufacturing costs. The task consists of comparing several prototype composite feedlines made by various methods. These methods are electron-beam curing, standard hand lay-up and autoclave cure, solvent assisted resin transfer molding, and thermoplastic tape laying. One of the critical technology drivers for composite components is resistance to foreign objects damage. This paper presents results of an experimental study of the damage resistance of the candidate materials that the prototype feedlines are manufactured from. The materials examined all have a 5-harness weave of IM7 as the fiber constituent (except for the thermoplastic, which is unidirectional tape laid up in a bidirectional configuration). The resin tested were 977-6, PR 520, SE-SA-1, RS-E3 (e-beam curable), Cycom 823 and PEEK. The results showed that the 977-6 and PEEK were the most damage resistant in all tested cases.

  14. Non-destructive ultrasonic evaluation of thermal damage in cementitious materials

    Energy Technology Data Exchange (ETDEWEB)

    Masse, S.; Vetter, G.; Boch, P. [Ecole Superieure de Physique et de Chimie Industrielles, Paris (France). Lab. of Ceramics and Minerals

    2002-07-01

    Thermal damage in cementitious materials (cement paste and microconcretes) subjected to high temperatures (T) up to 1000 C was monitored using a non-destructive, ultrasonic method of measurement of Young's modulus (E). Four cements were used: a Portland cement, two slag cements, and a ternary blend cement. Microconcretes were made by mixing cement, silica fume, quartz sand, and superplasticizer. Heat treating the materials at increasing T results in a decrease in E, more pronounced in microconcretes than in pastes. For a given sort of material (i.e. pastes or microconcretes) the curves of E/E{sub 0} = f[T] follow the same trend, whatever the kind of cement. (orig.)

  15. Damage Characterization and Real-Time Health Monitoring of Aerospace Materials Using Innovative NDE Tools

    Science.gov (United States)

    Matikas, Theodore E.

    2010-07-01

    The objective of this work is to characterize the damage and monitor in real-time aging structural components used in aerospace applications by means of advanced nondestructive evaluation techniques. Two novel experimental methodologies are used in this study, based on ultrasonic microscopy and nonlinear acoustics. It is demonstrated in this work that ultrasonic microscopy can be successfully utilized for local elastic property measurement, crack-size determination as well as for interfacial damage evaluation in high-temperature materials, such as metal matrix composites. Nonlinear acoustics enables real-time monitoring of material degradation in aerospace structures. When a sinusoidal ultrasonic wave of a given frequency and of sufficient amplitude is introduced into a nonharmonic solid, the fundamental wave distorts as it propagates, and therefore the second and higher harmonics of the fundamental frequency are generated. Measurements of the amplitude of these harmonics provide information on the coefficient of second- and higher-order terms of the stress-strain relation for a nonlinear solid. It is shown in this article that the material bulk nonlinear parameter for metallic alloy samples at different fatigue levels exhibits large changes compared to linear ultrasonic parameters, such as velocity and attenuation.

  16. Damage detection of hybrid aramid/metal–PVB composite materials using optical fiber sensors

    Directory of Open Access Journals (Sweden)

    A. Kojović

    2009-09-01

    Full Text Available Embedding optical fiber sensors within laminar thermoplastic composite material results in forming a system known as «smart structure». These sensors present the information about the inner structure health during the material exploitation and especially in the case of exterior impacts when a geometric configuration or the property changes of the material should be expected. This paper evaluates the feasibility of the real-time monitoring of indentation and low energy impact damage in composite laminates from indentation loading and Charpy pendulum impact, using the embedded intensity-based optical fiber sensors. An optical fiber sensing system, which relies solely on monitoring light intensity for providing the indication of the composite structural health, offers simplicity in design and cost-effectiveness. For this, aramid/polyvinylbutyral (PVB and aramid/metal/PVB laminates with embedded optical fibers were fabricated. Four configurations of woven composites were tested, namely, aramid/PVB, and aramid/metal/PVB in three stacking sequences of aramid and metallic woven layers. The initiation of damage and fracture during testing was detected by observation of the intensity drop of light signal transmitted through an optical fiber.

  17. Development of a Nondestructive Non-Contact Acousto-Thermal Evaluation Technique for Damage Detection in Materials (Preprint)

    Science.gov (United States)

    2011-11-01

    evaluate incipient thermal damage in composite structures. An aluminum aircraft wheel with a crack was used to show the applicability of the technique...ultrasonic and thermography NDE techniques have been valuable in detecting damage due to sub-surface delamination. Thermal exposure of PMCs can cause...AFRL-RX-WP-TP-2011-4366 DEVELOPMENT OF A NONDESTRUCTIVE NON- CONTACT ACOUSTO-THERMAL EVALUATION TECHNIQUE FOR DAMAGE DETECTION IN MATERIALS

  18. Evaluation of surface fractal dimension of carbon for plasma-facing material damaged by hydrogen plasma

    International Nuclear Information System (INIS)

    Nishino, Nobuhiro

    1997-01-01

    The surface structure of the plasma facing materials (PFM) changes due to plasma-surface interaction in a nuclear fusion reactor. Usually B 4 C coated graphite block are used as PFM. In this report, the surface fractal was applied to study the surface structure of plasma-damaged PFM carbon. A convenient flow-type adsorption apparatus was developed to evaluate the surface fractal dimension of materials. Four branched alkanol molecules with different apparent areas were used as the probe adsorbates. The samples used here were B 4 C coated isotopic graphite which were subjected to hydrogen plasma for various periods of exposure. The monolayer capacities of these samples for alkanols were determined by applying BET theory. The surface fractal dimension was calculated using the monolayer capacities and molecular areas for probe molecules and was found to increase from 2 to 3 with the plasma exposure time. (author)

  19. Microbial growth in building material samples and occupants' health in severely moisture-damaged homes.

    Science.gov (United States)

    Järvi, K; Hyvärinen, A; Täubel, M; Karvonen, A M; Turunen, M; Jalkanen, K; Patovirta, R; Syrjänen, T; Pirinen, J; Salonen, H; Nevalainen, A; Pekkanen, J

    2018-03-01

    There is no commonly approved approach to detect and quantify the health-relevant microbial exposure in moisture-damaged buildings. In 39 single-family homes with severe moisture damage, we studied whether concentrations of viable microbes in building material samples are associated with health among 71 adults and 68 children, and assessed with symptoms questionnaires, exhaled NO, and peak expiratory flow (PEF) variability. Symptoms were grouped into three scores: upper respiratory symptoms, lower respiratory symptoms, and general symptoms. The homes were divided into three groups based on viable counts of fungi, actinomycetes, and total bacteria cultivated from building material samples. Highest group of actinomycete counts was associated with more general symptoms, worse perceived health, and higher daily PEF variability (aOR 12.51; 1.10-141.90 as compared to the lowest group) among adults, and with an increase in lower respiratory symptoms in children, but the confidence intervals were wide. We observed significant associations of fungal counts and total microbial score with worse perceived health in adults. No associations with exhaled NO were observed. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. A coupled interface-body nonlocal damage model for the analysis of FRP strengthening detachment from cohesive material

    Directory of Open Access Journals (Sweden)

    J. Toti

    2011-10-01

    Full Text Available In the present work, a new model of the FRP-concrete or masonry interface, which accounts for the coupling occurring between the degradation of the cohesive material and the FRP detachment, is presented; in particular, a coupled interface-body nonlocal damage model is proposed. A nonlocal damage and plasticity model is developed for the quasi-brittle material. For the interface, a model which accounts for the mode I, mode II and mixed mode of damage and for the unilateral contact and friction effects is developed. Two different ways of performing the coupling between the body damage and the interface damage are proposed and compared. Some numerical applications are carried out in order to assess the performances of the proposed model in reproducing the mechanical behavior of the masonry elements strengthened with external FRP reinforcements.

  1. Prostaglandins and their precursors can modify genetic damage-induced by gamma-radiation and benzo(a)pyrene

    International Nuclear Information System (INIS)

    Das, U.N.; Ramadevi, G.; Rao, K.P.; Rao, M.S.

    1985-01-01

    Experiments were performed to study the effect of various prostaglandins (PGs) and their precursors, gamma-linolenic acid (GLA) and arachidonic acid (AA) on gamma-radiation and benzo (a) pyrene (BP)-induced genetic damage to the bone marrow cells of mice, using the sensitive micronucleus (MN) test. Thromboxane B2 prostaglandin E1 and GLA completely prevented BP-induced and reduced to a great degree radiation-induced genetic damage, where as PGE2, PGF2 alpha and AA were without any effect. Since GLA and AA are widely distributed in the cell membranes, and as PGs can be formed virtually in response to any type of stimulus, it is likely that GLA and PGE1 may function as endogenous anti-mutagenic chemicals

  2. Nonlinear absorption and optical damage threshold of carbon-based nanostructured material embedded in a protein

    Science.gov (United States)

    Janulewicz, K. A.; Hapiddin, A.; Joseph, D.; Geckeler, K. E.; Sung, J. H.; Nickles, P. V.

    2014-12-01

    Physical processes in laser-matter interaction used to be determined by generation of fast electrons resulting from efficient conversion of the absorbed laser radiation. Composite materials offer the possibility to control the absorption by choice of the host material and dopants. Reported here strong absorption of ultrashort laser pulse in a composite carbon-based nanomaterial including single-walled carbon nanotubes (SWCNTs) or multilayer graphene was measured in the intensity range between 1012 and 1016 W cm-2. A protein (lysozyme) was used as the host. The maximum absorption of femtosecond laser pulse has reached 92-96 %. The optical damage thresholds of the coatings were registered at an intensity of (1.1 ± 0.5) × 1013 W cm-2 for the embedded SWCNTs and at (3.4 ± 0.3) × 1013 W cm-2 for the embedded graphene. Encapsulated variant of the dispersed nanomaterial was investigated as well. It was found that supernatant protein in the coating material tends to dominate the absorption process, independently of the embedded nanomaterial. The opposite was observed for the encapsulated material.

  3. Recent developments in neutron dosimetry and radiation damage calculations for fusion-materials studies

    International Nuclear Information System (INIS)

    Greenwood, L.R.

    1983-01-01

    This paper is intended as an overview of activities designed to characterize neutron irradiation facilities in terms of neutron flux and energy spectrum and to use these data to calculate atomic displacements, gas production, and transmutation during fusion materials irradiations. A new computerized data file, called DOSFILE, has recently been developed to record dosimetry and damage data from a wide variety of materials test facilities. At present data are included from 20 different irradiations at fast and mixed-spectrum reactors, T(d,n) 14 MeV neutron sources, Be(d,n) broad-spectrum sources, and spallation neutron sources. Each file entry includes activation data, adjusted neutron flux and spectral data, and calculated atomic displacements and gas production. Such data will be used by materials experimenters to determine the exposure of their samples during specific irradiations. This data base will play an important role in correlating property changes between different facilities and, eventually, in predicting materials performance in fusion reactors. All known uncertainties and covariances are listed for each data record and explicit references are given to nuclear decay data and cross sections

  4. Damage detection on polymeric matrix composite materials by using acoustic emission technique

    Directory of Open Access Journals (Sweden)

    J. Cauich–Cupul

    2008-04-01

    Full Text Available In order to predict the mechanical behaviour of a composite during its service life, it is important to study the initiation and development of cracks and its effects induced by degradation. The onset of damage is related to the structural integrity of the component and its fatigue life. For this, among other reasons, non–destructive techniques have been widely used nowadays in composite materials characterization such as acoustic emission (AE. This method has demonstrated excellent results on detecting and identifying initiations sites, cracking propagation and fracture mechanisms of polymer matrix composite materials. At the same time, mechanical behaviour has been related intimately to the reinforcement architecture. The goal of this paper is to remark the importance of acoustic emission technique as a unique tool for characterising mechanical parameters in response to external stresses and degradation processes. Some results obtained from different analysis are discussed to support the significance of using AE, technique that will be increased continuously in the composite materials field due to its several alternatives for understanding the mechanical behaviour, therefore the objective of this manuscript is to involve the benefits and advantages of AE in the materials characterization.

  5. Analysis and Characterization of Damage and Failure Utilizing a Generalized Composite Material Model Suitable for Use in Impact Problems

    Science.gov (United States)

    Goldberg, Robert K.; Carney, Kelly S.; DuBois, Paul; Khaled, Bilal; Hoffarth, Canio; Rajan, Subramaniam; Blankenhorn, Gunther

    2016-01-01

    A material model which incorporates several key capabilities which have been identified by the aerospace community as lacking in state-of-the art composite impact models is under development. In particular, a next generation composite impact material model, jointly developed by the FAA and NASA, is being implemented into the commercial transient dynamic finite element code LS-DYNA. The material model, which incorporates plasticity, damage, and failure, utilizes experimentally based tabulated input to define the evolution of plasticity and damage and the initiation of failure as opposed to specifying discrete input parameters (such as modulus and strength). The plasticity portion of the orthotropic, three-dimensional, macroscopic composite constitutive model is based on an extension of the Tsai-Wu composite failure model into a generalized yield function with a non-associative flow rule. For the damage model, a strain equivalent formulation is utilized to allow for the uncoupling of the deformation and damage analyses. In the damage model, a semi-coupled approach is employed where the overall damage in a particular coordinate direction is assumed to be a multiplicative combination of the damage in that direction resulting from the applied loads in the various coordinate directions. Due to the fact that the plasticity and damage models are uncoupled, test procedures and methods to both characterize the damage model and to covert the material stress-strain curves from the true (damaged) stress space to the effective (undamaged) stress space have been developed. A methodology has been developed to input the experimentally determined composite failure surface in a tabulated manner. An analytical approach is then utilized to track how close the current stress state is to the failure surface.

  6. A methodology for the economic assessment of material damage caused by SO2 and NOx emissions in Europe

    International Nuclear Information System (INIS)

    Mayerhofer, P.; Weltschev, M.; Trukenmueller, A.; Friedrich, R.

    1995-01-01

    Damage to materials causes high economic losses in Europe. A large part of this damage can be attributed to the emissions caused by the energy and the transport sector. In the paper, the procedure for the economic assessment of material damages caused by SO 2 and NO x emissions in Europe is described. Model and data requirements are outlined, and gaps and uncertainties of the quantification are discussed. Two types of results are presented. First, the marginal (additional) costs of damage to material caused by an additional power plant are assessed. The analysis covers plants with different technologies. Results for the fossil power plants are in the range of 0.0062 to 0.12 mECU/kWh. In addition, the total economic material damage due to the present air pollution was assessed. It is in the range of 2.9 to 5.3 x 10 9 ECU/year. However, the analysis has many uncertainties. Most noteworthy are the material inventories and partially the damage functions and input data. 15 refs., 1 fig., 1 tab

  7. Assessment of extent and degree of thermal damage to polymeric materials in the Three Mile Island Unit 2 reactor building

    International Nuclear Information System (INIS)

    Alvares, N.J.

    1986-01-01

    This paper describes assumptions and procedures used to perform thermal damage analysis caused by post loss-of-coolant-accident (LOCA) hydrogen deflagration at Three Mile Island Unit 2 Reactor. Examination of available photographic evidence yields data on the extent and range of thermal and burn damage. Thermal damage to susceptible material in accessible regions of the reactor building was distributed in non-uniform patterns. No clear explanation for non-uniformity was found in examined evidence, e.g., burned materials were adjacent to materials that appear similar but were not burned. Because these items were in proximity to vertical openings that extend the height of the reactor building, the authors assume the unburned materials preferentially absorbed water vapor during periods of high, local steam concentration. A control pendant from the polar crane located in the top of the reactor building sustained asymmetric burn damage of decreasing degree from top to bottom. Evidence suggests the polar-crane pendant side that experienced heaviest damage was exposed to intense radiant energy from a transient fire plume in the reactor containment volume. Simple hydrogen-fire-exposure tests and heat transfer calculations approximate the degree of damage found on inspected materials from the containment building and support for an estimated 8% pre-fire hydrogen

  8. Assessment of extent and degree of thermal damage to polymeric materials in the Three Mile Island Unit 2 Reactor building

    International Nuclear Information System (INIS)

    Alvares, N.J.

    1985-06-01

    This paper describes assumptions and procedures used to perform thermal damage analysis caused by post loss-of-coolant-accident (LOCA) hydrogen deflagration at Three Mile Island Unit 2 Reactor. Examination of available photographic evidence yields data on the extent and range of thermal and burn damage. Thermal damage to susceptible material in accessible regions of the reactor building was distributed in non-uniform patterns. No clear explanation for non-uniformity was found in examined evidence, e.g., burned materials were adjacent to materials that appear similar but were not burned. Because these items were in proximity to vertical openings that extend the height of the reactor building, we assume the unburned materials preferentially absorbed water vapor during periods of high, local steam concentration. A control pendant from the polar crane located in the top of the reactor building sustained asymmetric burn damage of decreasing degree from top to bottom. Evidence suggests the polar-crane pendant side that experienced heaviest damage was exposed to intense radiant energy from a transient fire plume in the reactor containment volume. Simple hydrogen-fire-exposure tests and heat transfer calculations approximate the degree of damage found on inspected materials from the containment building and support for an estimated 8% pre-fire hydrogen

  9. Acoustic emission: A useful tool for damage evaluation in composite materials

    Science.gov (United States)

    Mouzakis, Dionysios E.; Dimogianopoulos, Dimitrios G.

    2018-02-01

    High performance composites for aviation-related structures are prone to constant aging by environmental agents. Previous data from our work reported on the stiffening behaviour of glass fibre polyester composites used in the manufacturing of wind turbine blades. Airplanes from such composites are already on service nowadays. This justifies the detailed study of the exposure of high performance materials to environmental conditions such as varying temperature, humidity, ultraviolet radiation, in order to assess the impact of these important aging factors on their mechanical behaviour. The dramatic changes in the dynamic mechanical response of polymer matrix carbon fibre composites upon exposure to acceleration aging has been assessed in the present study. In order to assess the synergistic effect action of temperature and humidity on composites subjected to changes of temperature from -35 to +40 °C and humidity variations from climatic chamber for 60 days. Conditions were cycled, as if actual flight cycles of 3-4 hours per flight, were to be simulated. Dynamic mechanical analysis tests were performed in three point bending mode. Scanning of frequency and temperature were performed in order to determine both the viscoelastic response as well as the time-dependent behaviour of the aged materials. All tests were run both for aged and pristine materials for comparison purposes. Three point bending testing was performed in both static as well as in Dynamic mechanical analysis, for a range of temperatures and frequencies. Acoustic Emission damage detection was also performed during the three point bending test both in static and dynamic mode. The aged materials had gained in dynamic stiffness. In addition, that, the gain in the storage moduli, was accompanied by a decrease in the material damping ability, as determined by the tanδ parameter. In the final stages of the study, impact testing was performed on both pristine and aged specimens. The experimentally recorded

  10. Damage tolerant design and condition monitoring of composite material and bondlines in wind turbine blades: Failure and crack propagation

    DEFF Research Database (Denmark)

    Pereira, Gilmar Ferreira; Mikkelsen, Lars Pilgaard; McGugan, Malcolm

    2015-01-01

    This research presents a novel method to asses a crack growing/damage event in composite material, in polymer, or in structural adhesive using Fibre Bragg Grating (FBG) sensors embedded in the host material, and its application in to a composite material structure: Wind Turbine Trailing Edge....... A Structure-Material-Sensor Finite Element Method (FEM) model was developed to simulate the Fibre Bragg Grating sensor output response, when embedded in a host material (Composite material, polymer or adhesive), during a crack growing/damage event. This Structure-Material-Sensor model provides a tool...... to analyse the application of this monitoring technique in other locations/structures, by predicting the sensor output and deciding, based on this, the optimal sensor distribution/configuration....

  11. Adaptive coupling between damage mechanics and peridynamics: a route for objective simulation of material degradation up to complete failure

    KAUST Repository

    Han, Fei

    2016-05-17

    The objective (mesh-independent) simulation of evolving discontinuities, such as cracks, remains a challenge. Current techniques are highly complex or involve intractable computational costs, making simulations up to complete failure difficult. We propose a framework as a new route toward solving this problem that adaptively couples local-continuum damage mechanics with peridynamics to objectively simulate all the steps that lead to material failure: damage nucleation, crack formation and propagation. Local-continuum damage mechanics successfully describes the degradation related to dispersed microdefects before the formation of a macrocrack. However, when damage localizes, it suffers spurious mesh dependency, making the simulation of macrocracks challenging. On the other hand, the peridynamic theory is promising for the simulation of fractures, as it naturally allows discontinuities in the displacement field. Here, we present a hybrid local-continuum damage/peridynamic model. Local-continuum damage mechanics is used to describe “volume” damage before localization. Once localization is detected at a point, the remaining part of the energy is dissipated through an adaptive peridynamic model capable of the transition to a “surface” degradation, typically a crack. We believe that this framework, which actually mimics the real physical process of crack formation, is the first bridge between continuum damage theories and peridynamics. Two-dimensional numerical examples are used to illustrate that an objective simulation of material failure can be achieved by this method.

  12. Assessment of Extent and Degree of Thermal Damage to Polymeric Materials in the Three Mile Island Unit 2 Reactor Building

    International Nuclear Information System (INIS)

    Alvares, N. J.

    1984-02-01

    Thermal damage to susceptible materials in accessible regions of the TMI-2 reactor building shows damage-distribution patterns that indicate non-uniform intensity of exposure. No clear explanation for non-uniformity is found in existing evidence; e.g., in some regions a lack of thermally susceptible materials frustrates analysis. Elsewhere, burned materials are present next to materials that seem similar but appear unscathed-leading to conjecture that the latter materials preferentially absorb water vapor during periods of high local steam concentration. Most of the polar crane pendant shows heavy burns on one half of its circumferential surface. This evidence suggests that the polar crane pendant side that experienced heaviest burn damage was exposed to intense radiant energy from a transient fire plume in the reactor containment volume. Tests and simple heat-transfer calculations based on pressure and temperature records from the accident show that the atmosphere inside the reactor building was probably 8% hydrogen in air, a value not inconsistent with the extent of burn damage. Burn-pattern geography indicates uniform thermal exposure in the dome volume to the 406-ft level (about 6 ft below the polar crane girder), partial thermal exposure in the volume between the 406- and 347-ft levels as indicated by the polar crane cable, and lack of damage to most thermally susceptible materials in the west quadrant of the reactor building; some evidence of thermal exposure Is seen in the free volume between the 305- and 347-ft levels. (author)

  13. Designing Multiagent Dental Materials for Enhanced Resistance to Biofilm Damage at the Bonded Interface.

    Science.gov (United States)

    Melo, Mary Anne; Orrego, Santiago; Weir, Michael D; Xu, Huakun H K; Arola, Dwayne D

    2016-05-11

    The oral environment is considered to be an asperous environment for restored tooth structure. Recurrent dental caries is a common cause of failure of tooth-colored restorations. Bacterial acids, microleakage, and cyclic stresses can lead to deterioration of the polymeric resin-tooth bonded interface. Research on the incorporation of cutting-edge anticaries agents for the design of new, long-lasting, bioactive resin-based dental materials is demanding and provoking work. Released antibacterial agents such as silver nanoparticles (NAg), nonreleased antibacterial macromolecules (DMAHDM, dimethylaminohexadecyl methacrylate), and released acid neutralizer amorphous calcium phosphate nanoparticles (NACP) have shown potential as individual and dual anticaries approaches. In this study, these agents were synthesized, and a prospective combination was incorporated into all the dental materials required to perform a composite restoration: dental primer, adhesive, and composite. We focused on combining different dental materials loaded with multiagents to improve the durability of the complex dental bonding interface. A combined effect of bacterial acid attack and fatigue on the bonding interface simulated the harsh oral environment. Human saliva-derived oral biofilm was grown on each sample prior to the cyclic loading. The oral biofilm viability during the fatigue performance was monitored by the live-dead assay. Damage of the samples that developed during the test was quantified from the fatigue life distributions. Results indicate that the resultant multiagent dental composite materials were able to reduce the acidic impact of the oral biofilm, thereby improving the strength and resistance to fatigue failure of the dentin-resin bonded interface. In summary, this study shows that dental restorative materials containing multiple therapeutic agents of different chemical characteristics can be beneficial toward improving resistance to mechanical and acidic challenges in oral

  14. Influence of frost damage and sample preconditioning on the porosity characterization of cement based materials using low temperature calorimetry

    DEFF Research Database (Denmark)

    Wu, Min; Fridh, Katja; Johannesson, Björn

    2015-01-01

    Low temperature calorimetry (LTC) can be used to study the meso-porosity of cement based materials. The influence of frost damage on the meso-porosity determination by LTC was explored on a model material MCM-41 and two cement pastes by conducting repeated cycles of freezing and melting measureme...

  15. Compilation of radiation damage test data. Pt. 2. Thermoset and thermoplastic resins, composite materials

    International Nuclear Information System (INIS)

    Tavlet, M.; Fontaine, A.; Schoenbacher, H.

    1998-01-01

    This catalogue summarizes radiation damage test data on thermoplastic and thermoset resins and composites. Most of them are epoxy resins used as insulator for magnet coils. Many results are also given for new engineering thermoplastics which can be used either for their electrical properties or for their mechanical properties. The materials have been irradiated either in a 60 Co source, up to integrated absorbed doses between 200 kGy and a few megagrays, at dose rates of the order of 1 Gy/s, or in a nuclear reactor at dose rates of the order of 50 Gy/s, up to doses of 100 MGy. The flexural strength, the deformation and the modulus of elasticity have been measured on irradiated and non-irradiated samples, according to the recommendations of the International Electrotechnical Commissions. The results are presented in the form of tables and graphs to show the effect of the absorbed dose on the measured properties. (orig.)

  16. Comparison of Interfacial Strengthening in Creep Deformation and Radiation Damage Processes of Advanced Structural Materials for Nuclear Applications

    Science.gov (United States)

    Zhu, Hanliang

    2018-02-01

    The mechanisms for microstructural strengthening in creep deformation and radiation damage processes of advanced structural materials for nuclear applications are compared. During creep and irradiation, various defects are generated and move in the microstructure. Any microstructural features that can retard such defect movement may improve both creep and radiation damage resistance. Interfaces in the microstructure are important barriers for preventing defect motion. To achieve ultrahigh strength and enhanced radiation damage resistance, an extremely high density of interfaces has been designed in recently developed nanostructured materials. However, interface-mediated processes may govern the deformation of these materials, decreasing their creep properties. Methods for improving the creep resistance of nanostructured materials are reviewed and discussed.

  17. Primary Radiation Damage in Materials. Review of Current Understanding and Proposed New Standard Displacement Damage Model to Incorporate in Cascade Defect Production Efficiency and Mixing Effects

    International Nuclear Information System (INIS)

    Nordlund, Kai; Sand, Andrea E.; Granberg, Fredric; Zinkle, Steven J.; Stoller, Roger; Averback, Robert S.; Suzudo, Tomoaki; Malerba, Lorenzo; Banhart, Florian; Weber, William J.; Willaime, Francois; Dudarev, Sergei; Simeone, David

    2015-01-01

    Under the auspices of the NEA Nuclear Science Committee (NSC), the Working Party on Multi-scale Modelling of Fuels and Structural Materials for Nuclear Systems (WPMM) was established in 2008 to assess the scientific and engineering aspects of fuels and structural materials, aiming at evaluating multi-scale models and simulations as validated predictive tools for the design of nuclear systems, fuel fabrication and performance. The WPMM's objective is to promote the exchange of information on models and simulations of nuclear materials, theoretical and computational methods, experimental validation, and related topics. It also provides member countries with up-to-date information, shared data, models and expertise. The WPMM Expert Group on Primary Radiation Damage (PRD) was established in 2009 to determine the limitations of the NRT-dpa standard, in the light of both atomistic simulations and known experimental discrepancies, to revisit the NRT-dpa standard and to examine the possibility of proposing a new improved standard of primary damage characteristics. This report reviews the current understanding of primary radiation damage from neutrons, ions and electrons (excluding photons, atomic clusters and more exotic particles), with emphasis on the range of validity of the 'displacement per atom' (dpa) concept in all major classes of materials with the exception of organics. The report also introduces an 'athermal recombination-corrected dpa' (arc-dpa) relation that uses a relatively simple functional to address the well-known issue that 'displacement per atom' (dpa) overestimates damage production in metals under energetic displacement cascade conditions, as well as a 'replacements-per-atom' (rpa) equation, also using a relatively simple functional, that accounts for the fact that dpa is understood to severely underestimate actual atom relocation (ion beam mixing) in metals. (authors)

  18. Use of conventional and chirped optical fibre Bragg gratings to detect matrix cracking damage in composite materials

    International Nuclear Information System (INIS)

    Palaniappan, J; Wang, H; Ogin, S L; Thorne, A; Reed, G T; Tjin, S C

    2005-01-01

    A comparison is made between conventional (i.e. uniform) and chirped optical fibre Bragg gratings (FBGs) for the detection of matrix cracking damage in composite materials. Matrix cracking damage is generally the first type of visible damage to develop under load in the off-axis plies of laminated composites and is generally the precursor of more serious damage mechanisms, particularly delamination. The detection of this type of damage is thus important, particularly in aerospace applications. Using a uniform FBG, characteristic changes develop in the reflected spectrum which can be used to identify crack development in the composite. The additional advantage of using a chirped grating is that the crack position can also be located

  19. Combined model of strain-induced phase transformation and orthotropic damage in ductile materials at cryogenic temperatures

    CERN Document Server

    Garion, Cedric

    2003-01-01

    Ductile materials (like stainless steel or copper) show at cryogenic temperatures three principal phenomena: serrated yielding (discontinuous in terms of dsigma/depsilon), plastic strain-induced phase transformations and evolution of ductile damage. The present paper deals exclusively with the two latter cases. Thus, it is assumed that the plastic flow is perfectly smooth. Both in the case of damage evolution and for the gamma-alpha prime phase transformation, the principal mechanism is related to the formation of plastic strain fields. In the constitutive modeling of both phenomena, a crucial role is played by the accumulated plastic strain, expressed by the Odqvist parameter p. Following the general trends, both in the literature concerning the phase transformation and the ductile damage, it is assumed that the rate of transformation and the rate of damage are proportional to the accumulated plastic strain rate. The gamma-alpha prime phase transformation converts the initially homogenous material to a two-p...

  20. The study of sub-surface damage distributions during grinding process on different abrasion materials

    Science.gov (United States)

    Kuo, Ching-Hsiang; Huang, Chien-Yao; Yu, Zong-Ru; Shu, Shyu-Cheng; Chang, Keng-Shou; Hsu, Wei-Yao

    2017-10-01

    The grinding process is the primary technology for curvature generation (CG) on glass optics. The higher material removal rate (MRR) leads to deeper sub-surface damage (SSD) on lens surface. The SSD must be removed by following lapping and polishing processes to ensure the lens quality. However, these are not an easy and an efficient process to remove the SSD from ground surface directly for aspheric surfaces with tens or hundreds microns departure from bestfit- sphere (BFS). An efficient fabrication procedure for large aspheric departure on glass materials must be considered. We propose 3-step fabrication procedures for aspheric surface with larger departure. 1st step is to generate a specific aspheric surface with depth less than 10 μm of SSD residual. 2nd step is to remove SSD and keep the aspheric form by using Zeeko polisher with higher MRR pad. Final step is to figure and finish the aspheric surface by using QED MRF machine. In this study, we focus on the 1st step to investigate the residual depth of SSD after grinding process on different abrasion materials. The materials of tested part are fused silica, S-NPH2, and S-PHM52. The cross grinding would be configured and depth of SSD/surface roughness would be evaluated in this study. The characteristic of SSD could be observed after etching by confocal microscope. The experimental results show the depth of SSD below 31.1 μm with #400 grinding wheel. And the near 10 μm depth of SSD would be achieved with #1,000 grinding wheel. It means the aspherization polishing on large parts with large departure from best fit sphere would be replaced. The fabrication of large aspheric part would be efficient.

  1. Potentials of Optical Damage Assessment Techniques in Automotive Crash-Concepts composed of FRP-Steel Hybrid Material Systems

    Science.gov (United States)

    Dlugosch, M.; Spiegelhalter, B.; Soot, T.; Lukaszewicz, D.; Fritsch, J.; Hiermaier, S.

    2017-05-01

    With car manufacturers simultaneously facing increasing passive safety and efficiency requirements, FRP-metal hybrid material systems are one way to design lightweight and crashworthy vehicle structures. Generic automotive hybrid structural concepts have been tested under crash loading conditions. In order to assess the state of overall damage and structural integrity, and primarily to validate simulation data, several NDT techniques have been assessed regarding their potential to detect common damage mechanisms in such hybrid systems. Significant potentials were found particularly in combining 3D-topography laser scanning and X-Ray imaging results. Ultrasonic testing proved to be limited by the signal coupling quality on damaged or curved surfaces.

  2. Activity of the protector chlorophyllin or promoter of the genetic damage induced by the 1,2 dimethyl hydrazine

    International Nuclear Information System (INIS)

    Guerrero M, M.G.

    2004-01-01

    The chlorophyllin (CHLN) it is a porphyrin of soluble nutritious grade in water, derived of the chlorophyll that includes in their structure a copper atom. It has been reported that this pigment can act as anti mutagen, reducing the damage to the DNA caused by physical or chemical agents of direct or indirect action. Their anti carcinogen action has also been studied during the initiation phase induced for carcinogen as the aflatoxins and heterocyclic amines. In contrast the reports have increased on a probable promoter activity of the CHLN on the induced genetic damage. This effect was seen for the first time before the damage induced by alkylating agents in Salmonella. Recently it has been observed with the damage induced by gamma radiation, ENU and CrO 3 in somatic cells of the wing of Drosophila and in the induction of tumors for 1,2-dimethylhydrazine (DMH) in mice. Presently study is evaluated the protective effect or promoter of the CHLN before the genetic damage induced by 1,2-dimethylhydrazine, by means of the bioassay mutation and somatic recombination (SMART) in the wing of Drosophila melanogaster. Its were pretreated with CHLN or SAC to transheterocygotes larvas for two locus of the chromosome three mwh+/+flr 3 ; later on they are retarded the chronic treatment with DMH 0, 1, 2 and 3 days. It was measured the toxicity and the speed of development of the treated individuals. The wings of those adults that emerged were analyzed to register the number and the size of stains. The results indicated: differences in the viability of the individuals of the groups SAC + DMH vs CHLN + DMH only in the treated immediately after the pretreatment (DRT-0) that the CHLN doesn't modify the rate of the treated individuals development. The results of somatic mutation indicated that the CHLN has a protective effect only immediately after the pretreatment (DRT-0) however in DRT-1, 2 and 3 showed a promoter effect of genetic damage. (Author)

  3. Ovine Reference Materials and Assays for Prion Genetic Testing

    Science.gov (United States)

    Background: Genetic predisposition to scrapie in sheep is associated with variation in the peptide sequence of the ovine prion protein encoded by Prnp. Codon variants implicated in scrapie susceptibility or disease progression include those at amino acid positions 112, 136, 141, 154, and 171. Nin...

  4. Material State Awareness for Composites Part II: Precursor Damage Analysis and Quantification of Degraded Material Properties Using Quantitative Ultrasonic Image Correlation (QUIC

    Directory of Open Access Journals (Sweden)

    Subir Patra

    2017-12-01

    Full Text Available Material state awareness of composites using conventional Nondestructive Evaluation (NDE method is limited by finding the size and the locations of the cracks and the delamination in a composite structure. To aid the progressive failure models using the slow growth criteria, the awareness of the precursor damage state and quantification of the degraded material properties is necessary, which is challenging using the current NDE methods. To quantify the material state, a new offline NDE method is reported herein. The new method named Quantitative Ultrasonic Image Correlation (QUIC is devised, where the concept of microcontinuum mechanics is hybrid with the experimentally measured Ultrasonic wave parameters. This unique combination resulted in a parameter called Nonlocal Damage Entropy for the precursor awareness. High frequency (more than 25 MHz scanning acoustic microscopy is employed for the proposed QUIC. Eight woven carbon-fiber-reinforced-plastic composite specimens were tested under fatigue up to 70% of their remaining useful life. During the first 30% of the life, the proposed nonlocal damage entropy is plotted to demonstrate the degradation of the material properties via awareness of the precursor damage state. Visual proofs for the precursor damage states are provided with the digital images obtained from the micro-optical microscopy, the scanning acoustic microscopy and the scanning electron microscopy.

  5. Material State Awareness for Composites Part II: Precursor Damage Analysis and Quantification of Degraded Material Properties Using Quantitative Ultrasonic Image Correlation (QUIC).

    Science.gov (United States)

    Patra, Subir; Banerjee, Sourav

    2017-12-18

    Material state awareness of composites using conventional Nondestructive Evaluation (NDE) method is limited by finding the size and the locations of the cracks and the delamination in a composite structure. To aid the progressive failure models using the slow growth criteria, the awareness of the precursor damage state and quantification of the degraded material properties is necessary, which is challenging using the current NDE methods. To quantify the material state, a new offline NDE method is reported herein. The new method named Quantitative Ultrasonic Image Correlation (QUIC) is devised, where the concept of microcontinuum mechanics is hybrid with the experimentally measured Ultrasonic wave parameters. This unique combination resulted in a parameter called Nonlocal Damage Entropy for the precursor awareness. High frequency (more than 25 MHz) scanning acoustic microscopy is employed for the proposed QUIC. Eight woven carbon-fiber-reinforced-plastic composite specimens were tested under fatigue up to 70% of their remaining useful life. During the first 30% of the life, the proposed nonlocal damage entropy is plotted to demonstrate the degradation of the material properties via awareness of the precursor damage state. Visual proofs for the precursor damage states are provided with the digital images obtained from the micro-optical microscopy, the scanning acoustic microscopy and the scanning electron microscopy.

  6. Fundamental Processes of Coupled Radiation Damage and Mechanical Behavior in Nuclear Fuel Materials for High Temperature Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Phillpot, Simon; Tulenko, James

    2011-09-08

    The objective of this work has been to elucidate the relationship among microstructure, radiation damage and mechanical properties for nuclear fuel materials. As representative nuclear materials, we have taken an hcp metal (Mg as a generic metal, and Ti alloys for fast reactors) and UO2 (representing fuel). The degradation of the thermo-mechanical behavior of nuclear fuels under irradiation, both the fissionable material itself and its cladding, is a longstanding issue of critical importance to the nuclear industry. There are experimental indications that nanocrystalline metals and ceramics may be more resistant to radiation damage than their coarse-grained counterparts. The objective of this project look at the effect of microstructure on radiation damage and mechanical behavior in these materials. The approach to be taken was state-of-the-art, large-scale atomic-level simulation. This systematic simulation program of the effects of irradiation on the structure and mechanical properties of polycrystalline Ti and UO2 identified radiation damage mechanisms. Moreover, it will provided important insights into behavior that can be expected in nanocrystalline microstructures and, by extension, nanocomposites. The fundamental insights from this work can be expected to help in the design microstructures that are less susceptible to radiation damage and thermomechanical degradation.

  7. ±Genetic structure of the oak wilt vector beetle Platypus quercivorus: inferences toward the process of damaged area expansion

    Directory of Open Access Journals (Sweden)

    Nozaki Ai

    2010-10-01

    Full Text Available Abstract Background The ambrosia beetle, Platypus quercivorus, is the vector of oak wilt, one of the most serious forest diseases in Japan. Population genetics approaches have made great progress toward studying the population dynamics of pests, especially for estimating dispersal. Knowledge of the genetic structuring of the beetle populations should reveal their population history. Using five highly polymorphic microsatellite loci, 605 individuals from 14 sampling sites were assessed to infer the ongoing gene flow among populations as well as the processes of expansion of damaged areas. Results Population differentiation (FST = 0.047, G'ST = 0.167 was moderate and two major clusters were detected by several methods, dividing the samples into north-eastern and south-western populations, a similar genetic divergence was reported in host oak trees. Within the north-eastern populations, the subgroups mostly corresponded to differences in the collection period. The genetic characteristics of the population might have changed after 2 years due to the mixing of individuals between populations with enhanced migration related to population outbreaks. Because isolation by distance was detected for whole populations and also within the north-eastern populations, migration was considered to be limited between neighbouring populations, and most populations were suggested to be in genetic equilibrium of genetic drift and gene flow. Recent bottlenecks were found in some populations with no geographical bias; however, they were all from newly emerged oak wilt forests. The emergence of oak wilt should have induced intense fluctuations in the beetle population size. Conclusions Because the genetic boundaries coincide, we suggest that the geographical structuring of the beetle was formed by co-evolution with the host species. Our findings indicate the oak wilt expansion process.

  8. Assessment of thermal damage to polymeric materials by hydrogen deflagration in the Three Mile Island Unit 2 Reactor Building

    International Nuclear Information System (INIS)

    Alvares, N.J.

    1985-05-01

    Thermal damage to susceptible material in accessible regions of the reactor building was distributed in non-uniform patterns. No clear explanation for non-uniformity was found in examined evidence, e.g., burned materials were adjacent to materials that appear similar but were not burned. Because these items were in proximity to vertical openings that extend the height of the reactor building, we assume the unburned materials preferentially absorbed water vapor during periods of high, local steam concentration. Simple hydrogen-fire-exposure tests and heat transfer calculations duplicate the degree of damage found on inspected materials from the containment building. These data support estimated 8% pre-fire hydrogen concentration predictions based on various hydrogen production mechanisms

  9. Oswald Avery and the Identification of DNA as the Genetic Material

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 9. Oswald Avery and the Identification of DNA as the Genetic Material. S Mahadevan ... Author Affiliations. S Mahadevan1. Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012, India.

  10. Damage evaluation system for materials used in fossil thermal power plants

    Energy Technology Data Exchange (ETDEWEB)

    Okamura, Hiroyuki [Science Univ. of Tokyo (Japan); Sakai, Shinsuke [Tokyo Univ. (Japan); Tomita, Akira [Japan Power Engineering and Inspection Corp., Tokyo (Japan); Koyama, Teruo [Babcock Hitachi K.K., Tokyo (Japan); Sakurai, Shigeo; Kawasaki, Yoshiya [Hitachi Ltd., Ibaraki (Japan)

    1998-11-01

    The summary of this research paper is as follows: The fundamental design of the damage evaluation system is carried out based on the basic concept. Prototype systems for boilers and turbines have been constructed: (a) Boiler: (I) Evaluation part: Outer surface of the primary pendant superheater tube; (II) Damage mode: Creep; (III) Damage evaluation method: Hardness measurement method; (b) Turbine: (I) Evaluation part: Inner surface at the center bore of high pressure turbine rotor; (II) Damage mode: Creep; (III) Damage evaluation method: Electric potential method. (orig./MM)

  11. Oxidative stress and genetic damage among workers exposed primarily to organophosphate and pyrethroid pesticides.

    Science.gov (United States)

    Zepeda-Arce, Rigoberto; Rojas-García, Aurora Elizabeth; Benitez-Trinidad, Alma; Herrera-Moreno, José Francisco; Medina-Díaz, Irma Martha; Barrón-Vivanco, Briscia S; Villegas, Germán Pier; Hernández-Ochoa, Isabel; Sólis Heredia, María de Jesús; Bernal-Hernández, Yael Y

    2017-06-01

    The indiscriminate use of pesticides in agriculture and public health campaigns has been associated with an increase of oxidative stress and DNA damage, resulting in health outcomes. Some defense mechanisms against free radical-induced oxidative damage include the antioxidant enzyme systems. The aim of this study was to determine the levels of malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and the relationship of antioxidant enzyme levels with DNA damage among sprayers (workers) occupationally exposed to pesticides. The determinations of MDA and antioxidant enzymes were performed spectrophotometrically. The genotoxic effects were evaluated using the comet assay. The results showed a marginally significant decrease in SOD and CAT activities in the high exposure group compared to the control group. For MDA, statistically significant differences were found among people working long term vs. those working temporarily (P = 0.02) as sprayers. In the moderate exposure group, a positive correlation was observed between MDA levels and GPx activity. In the high exposure group, a negative correlation was observed between GR and CAT activities, and between MDA levels and GPx activities. Furthermore, in the high exposure group, a positive correlation between DNA damage parameters and MDA levels was observed. The results suggest an important role of antioxidant enzymes for the protection of DNA damage caused by occupational exposure to pesticides. © 2017 Wiley Periodicals, Inc.

  12. Patients with genetically heterogeneous synchronous colorectal cancer carry rare damaging germline mutations in immune-related genes

    Science.gov (United States)

    Cereda, Matteo; Gambardella, Gennaro; Benedetti, Lorena; Iannelli, Fabio; Patel, Dominic; Basso, Gianluca; Guerra, Rosalinda F.; Mourikis, Thanos P.; Puccio, Ignazio; Sinha, Shruti; Laghi, Luigi; Spencer, Jo; Rodriguez-Justo, Manuel; Ciccarelli, Francesca D.

    2016-01-01

    Synchronous colorectal cancers (syCRCs) are physically separated tumours that develop simultaneously. To understand how the genetic and environmental background influences the development of multiple tumours, here we conduct a comparative analysis of 20 syCRCs from 10 patients. We show that syCRCs have independent genetic origins, acquire dissimilar somatic alterations, and have different clone composition. This inter- and intratumour heterogeneity must be considered in the selection of therapy and in the monitoring of resistance. SyCRC patients show a higher occurrence of inherited damaging mutations in immune-related genes compared to patients with solitary colorectal cancer and to healthy individuals from the 1,000 Genomes Project. Moreover, they have a different composition of immune cell populations in tumour and normal mucosa, and transcriptional differences in immune-related biological processes. This suggests an environmental field effect that promotes multiple tumours likely in the background of inflammation. PMID:27377421

  13. Radiation genetic studies in garden pea. Part 2. Caffeine potentiation and chromosome damage

    International Nuclear Information System (INIS)

    Kaul, M.L.H.

    1979-01-01

    The effect of 1.5x10 -2 M caffeine post-treatments over the chromosome damage induced by 4kR X-ray 1.5x10 -2 M Maleic hydrazide (MH) and N-Nitroso-N-urethane (NMU) treatments in the root top cells of a normal and trigenic leaf mutant of Pisum sativum was studied. While MH and NMU produced S-dependent effects, X-rays induced non-delayed S-independent effects. These effects got potentiated by caffeine treatments. With MH, the potentiation occurred when the cells got exposed to caffeine during S-phase and with X-rays, it occurred when the irradiated cells are treated in G 2 or prophase stage. The caffeine potentiation of chromosome damage produced by MH was similar in the roots exposed to caffeine at 16 and 31degC but with NMU, the potentiation was lower at 31 than at 16degC. If the inhibitory effect of caffeine on gap filling process of the damaged DNA is the molecular mechanism responsible for caffeine potentiation of reproductive death it may be the mechanism responsible for the observed chromosome damage in MH treated cells exposed to caffeine during G 1 and S phase. But the X-irradiated cells are insensitive to caffeine at such phases. In these cells caffeine probably acts as an inhibitor of the photoreactivating enzymes for binding sites or with the substrate in the irradiated cells post-treated during G 2 and prophase. However, temperature independence of caffeine potentiation is not compatible with eithr of the above two views. Compared to the normal genotype, the trigenic mutant exhibited an increased chromosomal damage, but not the potentiation. Probably mutant genes reduce the resistance of a genome against mutagenic action, consequently enhance the suseptibility to chromosome damage. (author)

  14. Analysis and Characterization of Damage Utilizing an Orthotropic Generalized Composite Material Model Suitable for Use in Impact Problems

    Science.gov (United States)

    Goldberg, Robert K.; Carney, Kelly S.; DuBois, Paul; Hoffarth, Canio; Rajan, Subramaniam; Blankenhorn, Gunther

    2016-01-01

    The need for accurate material models to simulate the deformation, damage and failure of polymer matrix composites under impact conditions is becoming critical as these materials are gaining increased usage in the aerospace and automotive communities. In order to address a series of issues identified by the aerospace community as being desirable to include in a next generation composite impact model, an orthotropic, macroscopic constitutive model incorporating both plasticity and damage suitable for implementation within the commercial LS-DYNA computer code is being developed. The plasticity model is based on extending the Tsai-Wu composite failure model into a strain hardening-based orthotropic plasticity model with a non-associative flow rule. The evolution of the yield surface is determined based on tabulated stress-strain curves in the various normal and shear directions and is tracked using the effective plastic strain. To compute the evolution of damage, a strain equivalent semi-coupled formulation is used in which a load in one direction results in a stiffness reduction in multiple material coordinate directions. A detailed analysis is carried out to ensure that the strain equivalence assumption is appropriate for the derived plasticity and damage formulations that are employed in the current model. Procedures to develop the appropriate input curves for the damage model are presented and the process required to develop an appropriate characterization test matrix is discussed

  15. A new material to prevent urethral damage after implantation of artificial devices: an experimental study

    Directory of Open Access Journals (Sweden)

    Salvador Vilar Correia Lima

    Full Text Available ABSTRACT Objective To validate the application of the bacterial cellulose (BC membrane as a protecting barrier to the urethra. Materials and Methods Forty female Wistar rats (four groups of 10: Group 1 (sham, the urethra was dissected as in previous groups and nothing applied around; Group 2, received a 0.7cm strip of the BC applied around the urethra just below the bladder neck; Group 3, received a silicon strip with the same dimensions as in group 2; Group 4, had a combination of 2 and 3 groups being the silicon strip applied over the cellulosic material. Half of the animals in each group were killed at 4 and 8 months. Bladder and urethra were fixed in formalin for histological analysis. Results Inflammatory infiltrates were more intense at 4 months at lymphonodes (80% Grade 2, statistically different in the group 2 compared with groups 1 (p=0.0044 and 3 (p=0.0154. At 8 months, all samples were classified as grade 1 indicating a less intense inflammatory reaction in all groups. In group 2, at 8 months, there was a reduction in epithelial thickness (30±1μm when com-pared to groups 1 (p=0.0001 and 3 (p<0.0001. Angiogenesis was present in groups 2 and 4 and absent in group 3. In BC implant, at 4 and 8 months, it was significant when comparing groups 4 with 1 (p=0.0159. Conclusion BC membrane was well integrated to the urethral wall promoting tissue remodeling and strengthening based on morphometric and histological results and may be a future option to prevent urethral damage.

  16. Experimental measurements of surface damage and residual stresses in micro-engineered plasma facing materials

    Science.gov (United States)

    Rivera, David; Wirz, Richard E.; Ghoniem, Nasr M.

    2017-04-01

    The thermomechanical damage and residual stresses in plasma-facing materials operating at high heat flux are experimentally investigated. Materials with micro-surfaces are found to be more resilient, when exposed to cyclic high heat flux generated by an arc-jet plasma. An experimental facility, dedicated to High Energy Flux Testing (HEFTY), is developed for testing cyclic heat flux in excess of 10 MW/m2. We show that plastic deformation and subsequent fracture of the surface can be controlled by sample cooling. We demonstrate that W surfaces with micro-pillar type surface architecture have significantly reduced residual thermal stresses after plasma exposure, as compared to those with flat surfaces. X-ray diffraction (XRD) spectra of the W-(110) peak reveal that broadening of the Full Width at Half Maximum (FWHM) for micro-engineered samples is substantially smaller than corresponding flat surfaces. Spectral shifts of XRD signals indicate that residual stresses due to plasma exposure of micro-engineered surfaces build up in the first few cycles of exposure. Subsequent cyclic plasma heat loading is shown to anneal out most of the built-up residual stresses in micro-engineered surfaces. These findings are consistent with relaxation of residual thermal stresses in surfaces with micro-engineered features. The initial residual stress state of highly polished flat W samples is compressive (≈ -1.3 GPa). After exposure to 50 plasma cycles, the surface stress relaxes to -1.0 GPa. Micro-engineered samples exposed to the same thermal cycling show that the initial residual stress state is compressive at (- 250 MPa), and remains largely unchanged after plasma exposure.

  17. Damage behavior of REE-doped W-based material exposed to high-flux transient heat loads

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Jing [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Luo, Lai–Ma, E-mail: luolaima@126.com [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Laboratory of Nonferrous Metal Material and Processing Engineering of Anhui Province, Hefei 230009 (China); Lin, Jin–shan [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Zan, Xiang; Zhu, Xiao–yong [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Laboratory of Nonferrous Metal Material and Processing Engineering of Anhui Province, Hefei 230009 (China); Xu, Qiu [Research Reactor Institute, Kyoto University, Osaka-Fu 590-0494 (Japan); Wu, Yu–Cheng, E-mail: ycwu@hfut.edu.cn [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Laboratory of Nonferrous Metal Material and Processing Engineering of Anhui Province, Hefei 230009 (China)

    2016-12-15

    Pure W and W-Lu alloys were prepared by mechanical alloying (MA) and spark plasma sintering (SPS) technology. The performance and relevant damage mechanism of W-(0%, 2%, 5%, 10%) Lu alloys under transient heat loads were investigated using a laser beam heat load test to simulate the transient events in future nuclear fusion reactors. Scanning electron microscopy was used to observe the morphologies of the damaged surfaces and energy dispersive X-ray spectroscopy was used to conduct composition analysis. Damages to the surface such as cracks, pits, melting layers, Lu-rich droplets, and thermal ablation were observed. A mass of dense fuzz-like nanoparticles formed on the outer region of the laser-exposed area. Recrystallization, grain growth, increased surface roughness, and material erosion were also observed. W-Lu samples with low Lu content demonstrated better thermal performance than pure W, and the degree of damage significantly deteriorated under repetitive transient heat loads.

  18. Damage behavior of REE-doped W-based material exposed to high-flux transient heat loads

    International Nuclear Information System (INIS)

    Shi, Jing; Luo, Lai–Ma; Lin, Jin–shan; Zan, Xiang; Zhu, Xiao–yong; Xu, Qiu; Wu, Yu–Cheng

    2016-01-01

    Pure W and W-Lu alloys were prepared by mechanical alloying (MA) and spark plasma sintering (SPS) technology. The performance and relevant damage mechanism of W-(0%, 2%, 5%, 10%) Lu alloys under transient heat loads were investigated using a laser beam heat load test to simulate the transient events in future nuclear fusion reactors. Scanning electron microscopy was used to observe the morphologies of the damaged surfaces and energy dispersive X-ray spectroscopy was used to conduct composition analysis. Damages to the surface such as cracks, pits, melting layers, Lu-rich droplets, and thermal ablation were observed. A mass of dense fuzz-like nanoparticles formed on the outer region of the laser-exposed area. Recrystallization, grain growth, increased surface roughness, and material erosion were also observed. W-Lu samples with low Lu content demonstrated better thermal performance than pure W, and the degree of damage significantly deteriorated under repetitive transient heat loads.

  19. Probabilistic approaches applied to damage and embrittlement of structural materials in nuclear power plants

    International Nuclear Information System (INIS)

    Vincent, L.

    2012-01-01

    The present study deals with the long-term mechanical behaviour and damage of structural materials in nuclear power plants. An experimental way is first followed to study the thermal fatigue of austenitic stainless steels with a focus on the effects of mean stress and bi-axiality. Furthermore, the measurement of displacement fields by Digital Image Correlation techniques has been successfully used to detect early crack initiation during high cycle fatigue tests. A probabilistic model based on the shielding zones surrounding existing cracks is proposed to describe the development of crack networks. A more numeric way is then followed to study the embrittlement consequences of the irradiation hardening of the bainitic steel constitutive of nuclear pressure vessels. A crystalline plasticity law, developed in agreement with lower scale results (Dislocation Dynamics), is introduced in a Finite Element code in order to run simulations on aggregates and obtain the distributions of the maximum principal stress inside a Representative Volume Element. These distributions are then used to improve the classical Local Approach to Fracture which estimates the probability for a microstructural defect to be loaded up to a critical level. (author) [fr

  20. DNA damage in male gonad cells of Green mussel (Perna viridis) upon exposure to tobacco products

    Digital Repository Service at National Institute of Oceanography (India)

    Nagarajappa; Ganguly, A.; Goswami, U.

    , heavy metals, etc. Some of these chemicals are known genotoxicants and can cause damage to the genetic material of the exposed organism (Shugart, 1990). Damaged DNA may potentiate subsequent deleterious cellular events such as disease (e.g., cancer...

  1. Development and Evaluation of Cement-Based Materials for Repair of Corrosion-Damaged Reinforced Concrete Slabs

    OpenAIRE

    Liu, Rongtang; Olek, J.

    2001-01-01

    In this study, the results of an extensive laboratory investigation conducted to evaluate the properties of concrete mixes used as patching materials to repair reinforced concrete slabs damaged by corrosion are reported. Seven special concrete mixes containing various combinations of chemical or mineral admixtures were developed and used as a patching material to improve the durability of the repaired slabs. Physical and mechanical properties of these mixes, such as compressive strength, stat...

  2. Ternary alloy material prediction using genetic algorithm and cluster expansion

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chong [Iowa State Univ., Ames, IA (United States)

    2015-12-01

    This thesis summarizes our study on the crystal structures prediction of Fe-V-Si system using genetic algorithm and cluster expansion. Our goal is to explore and look for new stable compounds. We started from the current ten known experimental phases, and calculated formation energies of those compounds using density functional theory (DFT) package, namely, VASP. The convex hull was generated based on the DFT calculations of the experimental known phases. Then we did random search on some metal rich (Fe and V) compositions and found that the lowest energy structures were body centered cube (bcc) underlying lattice, under which we did our computational systematic searches using genetic algorithm and cluster expansion. Among hundreds of the searched compositions, thirteen were selected and DFT formation energies were obtained by VASP. The stability checking of those thirteen compounds was done in reference to the experimental convex hull. We found that the composition, 24-8-16, i.e., Fe3VSi2 is a new stable phase and it can be very inspiring to the future experiments.

  3. A PVC-foam material model based on a thermodynamically elasto-plastic-damage framework exhibiting failure and crushing

    NARCIS (Netherlands)

    Gielen, A.W.J.

    2008-01-01

    A well known foam for naval sandwiches is PVC (polyvinyl chloride) foam. This foam exhibits elasto-damage behavior under tension and elasto-plastic behavior under compression. A proper material model is required for the prediction of the failure and post-failure behavior of these sandwiches during

  4. Implementation of an anisotropic damage material model for non-proportional loading

    NARCIS (Netherlands)

    Niazi, Muhammad Sohail; Wisselink, H.H.; Meinders, Vincent T.; Huetink, Han; Onate, E; Owen, D.R.J

    2009-01-01

    Anisotropic damage for non-proportional loading is incorporated in an implicit finite element code under the framework of continuum damage models, using two different methodologies. Simple simulations are carried out to check the performance of the models. The advantages and drawbacks of both

  5. Salt damage in porous materials: a threat to the cultural heritage

    Directory of Open Access Journals (Sweden)

    Clifford Price

    1997-11-01

    Full Text Available Salt damage is one of the most pervasive threats to the long-term survival of historic and prehistoric structures and artefacts. Basic research at the Institute on the processes leading to salt damage is helping to ameliorate the problem.

  6. Going Deeper into Laser Damage: Experiments and Methods for Characterizing Materials in High Power Laser Systems

    Science.gov (United States)

    Taylor, Lucas Nathan

    Laser damage is a primary limiting factor to the design of high-power laser systems. This is true for short-pulse systems as well as long-pulse and continuous-wave (CW) systems. Unlike short-pulse laser damage, CW laser damage has been much less studied. This work comprises a background of laser damage and laser heating theory, a CW laser damage experiment and an imaging technique for monitoring laser heating. The damage experiment was performed on 100 nm thick hafnia coatings deposited on fused silica. Uniformly grown films were compared to hafnia-alumina nanolaminates. While the nanolaminates are known to perform better for 1 ns pulses, we found they had worse laser damage performance in the CW regime. We found the nanolaminates reduced crystallinity. The polycrystalline uniform films are thought to have increased absorption. We measured the thermal conductivity of the nanolaminates to be approximately 1/2 that of the uniform films. A theoretical model including the absorption and thermal conductivity of the nanolaminate and uniform film agreed with the experimental data for 1 ns pulses and CW tests. During laser damage experiments, anomalous damage morphologies were observed that we were unable to explain with theoretical techniques. We then developed an experimental method to observe high-speed laser damage events at the ms time-scale. We imaged laser heating and compared it to a theoretical model with good agreement. Our measurement method captured image data from a Mach- Zender interferometer that had do be processed ex-situ. We desired a system capable of providing real-time thermal data. We developed an image processing technique at least 66 times faster than the original method.

  7. Effect of damage on water retention and gas transport properties geo-materials: Application to geological storage of radioactive waste

    International Nuclear Information System (INIS)

    M'Jahad, S.

    2012-01-01

    In the context of geological disposal of radioactive waste, this work contributes to the characterization of the effect of diffuse damage on the water retention and gas transfer properties of concrete (CEM I and CEM V) selected by Andra, Callovo-Oxfordian argillite (host rock) and argillite / concrete interfaces. This study provides information on the concrete microstructure from Mercury porosimetry intrusion and water retention curves: each concrete has a distinct microstructure, CEM I concrete is characterized by a significant proportion of capillary pores while CEM V concrete has a large proportion of C-S-H pores. Several protocols have been developed in order to damage concrete. The damage reduces water retention capacity of CEM I concrete and increases its gas permeability. Indeed, gas breakthrough pressure decreases significantly for damaged concrete, and this regardless of the type of concrete. For argillite, the sample mass increases gradually at RH = 100%, which creates and increases damage in the material. This reduces its ability to retain water. Otherwise, water retention and gas transport properties of argillite are highly dependent of its initial water saturation, which is linked to its damage. Finally, we observed a clogging phenomenon at the argillite/concrete interfaces, which is first mechanical and then hydraulic (and probably chemical) after water injection. This reduces the gas breakthrough pressure interfaces. (author)

  8. Organophosphate-based pesticides and genetic damage implicated in bladder cancer.

    Science.gov (United States)

    Webster, Lucy R; McKenzie, Geoff H; Moriarty, Helen T

    2002-03-01

    Organophosphate-based pesticides have been associated with pathology and chromosomal damage in humans. There are also epidemiologic links with cancer. The few screening tests for low-level occupational exposure are of doubtful sensitivity; this investigation evaluated four methods. Blood samples were studied from 10 farmers before and after occupational exposure to organophosphate-based pesticides and five unexposed controls. The standard cholinesterase test was insensitive to the exposure (P=0.815). However, a significant increase in Howell-Jolly bodies within erythrocytes was observed (P=0.001). Cytogenetic studies on routine and aphidicolin-induced blood cultures revealed that following organophosphate exposure the total number of gaps and breaks on human chromosomes was significantly increased (P=0.004 and P=0.0006, respectively). We concluded that Howell-Jolly body and fragile site analysis were sensitive indicators of nuclear damage resulting from low-level occupational exposure to organophosphate. Such nuclear damage could be implicated in carcinogenesis. The development of bladder cancer is one such example.

  9. Analysis of PWI footprint traces and material damage on the first walls of the spherical tokamak QUEST

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, S.K., E-mail: sksharma@triam.kyushu-u.ac.jp [IGSES, Kyushu University, Kasuga, Fukuoka 816 8580 (Japan); Zushi, H.; Yoshida, N.; Watanabe, H. [Research Institute of Applied Mechanics, Kyushu University, Kasuga, Fukuoka 816 8580 (Japan); Osakabe, M.; Takeri, Y. [National Institute for Fusion Science, Toki 509 5292 (Japan); Hasegawa, M. [Research Institute of Applied Mechanics, Kyushu University, Kasuga, Fukuoka 816 8580 (Japan); Tanabe, T. [IGSES, Kyushu University, Kasuga, Fukuoka 816 8580 (Japan); Tokunaga, K.; Hanada, K.; Idei, H. [Research Institute of Applied Mechanics, Kyushu University, Kasuga, Fukuoka 816 8580 (Japan); Sakamoto, M. [PRC, University of Tsukuba, Ibaraki, 3058577 (Japan); Nakamura, K.; Fujisawa, A. [Research Institute of Applied Mechanics, Kyushu University, Kasuga, Fukuoka 816 8580 (Japan); Ishiguro, M.; Tashima, S. [IGSES, Kyushu University, Kasuga, Fukuoka 816 8580 (Japan)

    2012-01-15

    After several non-inductive current startup experimental campaigns in the spherical tokamak QUEST, its metallic first walls have revealed various kinds of damages as a signature of strong plasma wall interaction (PWI). Several types of footprint traces, namely colored regions formed due to material erosion/redeposition, melting of plasma facing components (PFCs) and numerous arc tracks on the chamber walls are recognized. Analysis of the re-deposited materials on collector probes is carried out using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). Redeposition of several impurity materials such as carbon, oxygen and tungsten is identified. The footprint traces are majorly formed on the lower side PFCs, showing a large up/down asymmetry. Both toroidally symmetric and asymmetric footprint traces are formed on the bottoms side divertor plate and the lower part of the outboard side walls, respectively. Localized melting occurred on the outboard side limiters is attributed to the loss of energetic electrons produced via electron cyclotron resonance (ECR) heating. The observed damages are discussed in view of localized PWI, loss of energetic electrons, particle drifts, sputtering, arcing and redeposition of eroded materials. Material analysis and numerically calculated guiding center orbits of the charge particles are used to discuss these damages.

  10. Analysis of PWI footprint traces and material damage on the first walls of the spherical tokamak QUEST

    International Nuclear Information System (INIS)

    Sharma, S.K.; Zushi, H.; Yoshida, N.; Watanabe, H.; Osakabe, M.; Takeri, Y.; Hasegawa, M.; Tanabe, T.; Tokunaga, K.; Hanada, K.; Idei, H.; Sakamoto, M.; Nakamura, K.; Fujisawa, A.; Ishiguro, M.; Tashima, S.

    2012-01-01

    After several non-inductive current startup experimental campaigns in the spherical tokamak QUEST, its metallic first walls have revealed various kinds of damages as a signature of strong plasma wall interaction (PWI). Several types of footprint traces, namely colored regions formed due to material erosion/redeposition, melting of plasma facing components (PFCs) and numerous arc tracks on the chamber walls are recognized. Analysis of the re-deposited materials on collector probes is carried out using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). Redeposition of several impurity materials such as carbon, oxygen and tungsten is identified. The footprint traces are majorly formed on the lower side PFCs, showing a large up/down asymmetry. Both toroidally symmetric and asymmetric footprint traces are formed on the bottoms side divertor plate and the lower part of the outboard side walls, respectively. Localized melting occurred on the outboard side limiters is attributed to the loss of energetic electrons produced via electron cyclotron resonance (ECR) heating. The observed damages are discussed in view of localized PWI, loss of energetic electrons, particle drifts, sputtering, arcing and redeposition of eroded materials. Material analysis and numerically calculated guiding center orbits of the charge particles are used to discuss these damages.

  11. Experimental study of discontinuous plastic flow, phase transformation and micro-damage evolution in ductile materials at cryogenic temperatures

    CERN Document Server

    Marcinek, Dawid Jarosław; Sgobba, S

    2009-01-01

    The present Thesis deals with three low temperature phenomena occurring in ductile materials subjected to mechanical loads: serrated yielding, plastic strain induced γ-α’ phase transformation and evolution of micro-damage: - the Thesis explains the physical mechanisms governing each phenomenon at the micro and macroscopic levels; - the document describes in detail the advanced laboratory equipment needed for cryogenic experiments; - the results of tests carried out with unique precision and focused on serrated yielding and evolution of micro-damage (the observations were made with different strain rates and with the use of different materials) are presented; - validation of suitable kinetic laws and identification of parameters for tested materials is carried out.

  12. Material State Awareness for Composites Part I: Precursor Damage Analysis Using Ultrasonic Guided Coda Wave Interferometry (CWI).

    Science.gov (United States)

    Patra, Subir; Banerjee, Sourav

    2017-12-16

    Detection of precursor damage followed by the quantification of the degraded material properties could lead to more accurate progressive failure models for composite materials. However, such information is not readily available. In composite materials, the precursor damages-for example matrix cracking, microcracks, voids, interlaminar pre-delamination crack joining matrix cracks, fiber micro-buckling, local fiber breakage, local debonding, etc.-are insensitive to the low-frequency ultrasonic guided-wave-based online nondestructive evaluation (NDE) or Structural Health Monitoring (SHM) (~100-~500 kHz) systems. Overcoming this barrier, in this article, an online ultrasonic technique is proposed using the coda part of the guided wave signal, which is often neglected. Although the first-arrival wave packets that contain the fundamental guided Lamb wave modes are unaltered, the coda wave packets however carry significant information about the precursor events with predictable phase shifts. The Taylor-series-based modified Coda Wave Interferometry (CWI) technique is proposed to quantify the stretch parameter to compensate the phase shifts in the coda wave as a result of precursor damage in composites. The CWI analysis was performed on five woven composite-fiber-reinforced-laminate specimens, and the precursor events were identified. Next, the precursor damage states were verified using high-frequency Scanning Acoustic Microscopy (SAM) and optical microscopy imaging.

  13. Damage Simulation in Composite Materials: Why It Matters and What Is Happening Currently at NASA in This Area

    Science.gov (United States)

    McElroy, Mack; de Carvalho, Nelson; Estes, Ashley; Lin, Shih-yung

    2017-01-01

    Use of lightweight composite materials in space and aircraft structure designs is often challenging due to high costs associated with structural certification. Of primary concern in the use of composite structures is durability and damage tolerance. This concern is due to the inherent susceptibility of composite materials to both fabrication and service induced flaws. Due to a lack of general industry accepted analysis tools applicable to composites damage simulation, a certification procedure relies almost entirely on testing. It is this reliance on testing, especially compared to structures comprised of legacy metallic materials where damage simulation tools are available, that can drive costs for using composite materials in aerospace structures. The observation that use of composites can be expensive due to testing requirements is not new and as such, research on analysis tools for simulating damage in composite structures has been occurring for several decades. A convenient approach many researchers/model-developers in this area have taken is to select a specific problem relevant to aerospace structural certification and develop a model that is accurate within that scope. Some examples are open hole tension tests, compression after impact tests, low-velocity impact, damage tolerance of an embedded flaw, and fatigue crack growth to name a few. Based on the premise that running analyses is cheaper than running tests, one motivation that many researchers in this area have is that if generally applicable and reliable damage simulation tools were available the dependence on certification testing could be lessened thereby reducing overall design cost. It is generally accepted that simulation tools if applied in this manner would still need to be thoroughly validated and that composite testing will never be completely replaced by analysis. Research and development is currently occurring at NASA to create numerical damage simulation tools applicable to damage in

  14. [Genetic damage in peripheral blood lymphocyte of 1,3-butadiene workers].

    Science.gov (United States)

    Liu, Nan; Wang, Xuesheng; Meng, Huilin; Cui, Tao; Cheng, Juan; Xiao, Jingwei; Li, Zhongsheng; Li, Bin

    2013-09-01

    To investigate the DNA and chromosome damage in peripheral blood lymphocyte of workers occupationally exposed to 1,3-butadiene (BD). Personal information including occupational history, age, sex, smoking and drinking status was collected by the questionnaire. Gas chromatography was used to analyze the BD level. One hundred and eighty 1,3-butadiene workers and 58 controls without occupational BD exposure were investigated. Comet assay and cytokinesis-block micronucleus (CBMN) detection were used to evaluate DNA and chromosomal damage levels in peripheral blood lymphocyte. The concentration of BD in the working environment of BD-exposed workers was 1.80 (0.59-2.76) mg/m3. The rate of CBMN, NPB, NBUD and Olive TM of lymphocyte in BD-exposed workers [(6.76 +/- 4.99) per thousand, 1.00 (0.00-4.00), 2.00 (0.00-7.00) and 4.64 (3.50-5.98), respectively] were higher than those in controls [(3.10 +/- 2.65) per thousdand, 0.00 (0.00-2.80), 1.00 (0.00- 5.00) and 2.34 (0.82-3.93), P < 0.01]. According to the length of work, 180 BD-exposed workers were classified into 3 groups: 1 yrs-, 14.0 yrs- and 20.0 yrs-group, respectively after adjusting the age,sex, smoking and drinking, the rate of CBMN was a rising tendency along with the increase in length of work. Under present BD exposure levels, both comet assay and Cytokinesis-block micronucleus test could detect BD-induced genotoxicity in BD-exposed workers, and are more suitable to assess the cumulative damage effect on DNA.

  15. Aberrations of Genetic Material as Biomarkers of Ionizing Radiation Effects

    Energy Technology Data Exchange (ETDEWEB)

    Milacic, S.

    2004-07-01

    significant difference of the number of aberrant cells and the sum of chromosome aberrations between the exposed and control groups (t-test;p<0.001). The sum of chromosome aberrations and the number of aberrant cells was in positive correlation with the duration of exposure (p<0.001), and to a less degree of probability with the age (p<0.05) in the exposed workers. In the controls, this correlation was negative and insignificant. the group of subjects with the duration of occupational exposure up to 15 years had significantly less number of aberrant cells and chromosome aberrations in comparison to the subjects with longer duration of occupational exposure, over 15 years. Long-term occupational exposure to low doses had the effect to the development and frequency of chromosome aberrations, especially unstable ones (dicentric), but it varied in relation to different working places in public health system. The majority of subjects had no genetic modifications affected by low doses, arguing for the significance of individual variability's in radio sensitivity and genetic predisposition. (Author)14 refs.

  16. Paraoxonase-1 genetic polymorphisms and susceptibility to DNA damage in workers occupationally exposed to organophosphate pesticides

    International Nuclear Information System (INIS)

    Singh, Satyender; Kumar, Vivek; Thakur, Sachin; Banerjee, Basu Dev; Rautela, Rajender Singh; Grover, Shyam Sunder; Rawat, Devendra Singh; Pasha, Syed Tazeen; Jain, Sudhir Kumar; Ichhpujani, Rattan Lal; Rai, Arvind

    2011-01-01

    Human paraoxonase 1 (PON1) is a lipoprotein-associated enzyme involved in the detoxification of organophosphate pesticides (OPs) by hydrolyzing the bioactive oxons. Polymorphisms of the PON1 gene are responsible for variation in the expression and catalytic activity of PON1 enzyme. In the present study, we have determined (a) the prevalence of two common PON1 polymorphisms, (b) the activity of PON1 and acetylcholinesterase enzymes, and (c) the influence of PON1 genotypes and phenotypes variation on DNA damage in workers exposed to OPs. We examined 230 subjects including 115 workers exposed to OPs and an equal number of normal healthy controls. The results revealed that PON1 activity toward paraoxon (179.19 ± 39.36 vs. 241.52 ± 42.32 nmol/min/ml in controls) and phenylacetate (112.74 ± 17.37 vs. 134.28 ± 25.49 μmol/min/ml in controls) was significantly lower in workers than in control subjects (p 192 QR (Gln/Arg) and PON1 55 LM (Leu/Met) in workers and control subjects (p > 0.05). The PON1 activity toward paraoxonase was found to be significantly higher in the R/R (Arg/Arg) genotypes than Q/R (Gln/Arg) and lowest in Q/Q (Gln/Gln) genotypes in both workers and control subjects (p 55 LM (Leu/Met), PON1 activity toward paraoxonase was observed to be higher in individuals with L/L (Leu/Leu) genotypes and lowest in individuals with M/M (Met/Met) genotypes in both groups (p < 0.001). No influence of PON1 genotypes and phenotypes was seen on the activity of acetylcholinesterase and arylesterase. The DNA damage was observed to be significantly higher in workers than in control subjects (p < 0.05). Further, the individuals who showed least paraoxonase activity i.e., those with (Q/Q [Gln/Gln] and M/M [Met/Met]) genotypes showed significantly higher DNA damage compared to other isoforms in workers exposed to OPs (p < 0.05). The results indicate that the individuals with PON1 Q/Q and M/M genotypes are more susceptible toward genotoxicity. In conclusion, the study suggests

  17. Continuous Influx of Genetic Material from Host to Virus Populations.

    Directory of Open Access Journals (Sweden)

    Clément Gilbert

    2016-02-01

    Full Text Available Many genes of large double-stranded DNA viruses have a cellular origin, suggesting that host-to-virus horizontal transfer (HT of DNA is recurrent. Yet, the frequency of these transfers has never been assessed in viral populations. Here we used ultra-deep DNA sequencing of 21 baculovirus populations extracted from two moth species to show that a large diversity of moth DNA sequences (n = 86 can integrate into viral genomes during the course of a viral infection. The majority of the 86 different moth DNA sequences are transposable elements (TEs, n = 69 belonging to 10 superfamilies of DNA transposons and three superfamilies of retrotransposons. The remaining 17 sequences are moth sequences of unknown nature. In addition to bona fide DNA transposition, we uncover microhomology-mediated recombination as a mechanism explaining integration of moth sequences into viral genomes. Many sequences integrated multiple times at multiple positions along the viral genome. We detected a total of 27,504 insertions of moth sequences in the 21 viral populations and we calculate that on average, 4.8% of viruses harbor at least one moth sequence in these populations. Despite this substantial proportion, no insertion of moth DNA was maintained in any viral population after 10 successive infection cycles. Hence, there is a constant turnover of host DNA inserted into viral genomes each time the virus infects a moth. Finally, we found that at least 21 of the moth TEs integrated into viral genomes underwent repeated horizontal transfers between various insect species, including some lepidopterans susceptible to baculoviruses. Our results identify host DNA influx as a potent source of genetic diversity in viral populations. They also support a role for baculoviruses as vectors of DNA HT between insects, and call for an evaluation of possible gene or TE spread when using viruses as biopesticides or gene delivery vectors.

  18. Damage Identification of Trusses with Elastic Supports Using FEM and Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Nam-Il Kim

    2013-01-01

    Full Text Available The computationally efficient damage identification technique for truss structures with elastic supports is proposed based on the force method. To transform the truss with supports into the equivalent free-standing model without supports, the novel zero-length dummy members are employed. General equilibrium equations and kinematic relations, in which the reaction forces and the displacements at the elastic supports are taken into account, are clearly formulated. The compatibility equations, in terms of forces in which the flexibilities of elastic supports are considered, are explicitly presented using the singular value decomposition (SVD technique. Both member and reaction forces are simultaneously and directly obtained. Then, all nodal displacements including constrained nodes are back calculated from the member and reaction forces. Next, the microgenetic algorithm (MGA is used to properly identify the site and the extent of multiple damages in truss structures. In order to verify the superiority of the current study, the numerical solutions are presented for the planar and space truss models with and without elastic supports. The numerical results indicate that the computational effort required by this study is found to be significantly lower than that of the displacement method.

  19. Personal exposure to PM2.5, genetic variants and DNA damage: a multi-center population-based study in Chinese.

    Science.gov (United States)

    Chu, Minjie; Sun, Chongqi; Chen, Weihong; Jin, Guangfu; Gong, Jianhang; Zhu, Meng; Yuan, Jing; Dai, Juncheng; Wang, Meilin; Pan, Yun; Song, Yuanchao; Ding, Xiaojie; Guo, Xuejiang; Du, Mulong; Xia, Yankai; Kan, Haidong; Zhang, Zhengdong; Hu, Zhibin; Wu, Tangchun; Shen, Hongbing

    2015-06-15

    Exposure to particulate matter (e.g., PM2.5) may result in DNA damage, a major culprit in mutagenesis and environmental toxicity. DNA damage levels may vary among individuals simultaneously exposed to PM2.5, however, the genetic determinants are still unclear. To explore whether PM2.5 exposure and genetic variants contribute to the alteration in DNA damage, we recruited 328 subjects from three independent cohorts (119 from Zhuhai, 123 from Wuhan and 86 from Tianjin) in southern, central and northern China with different PM2.5 exposure levels. Personal 24-h PM2.5 exposure levels and DNA damage levels of peripheral blood lymphocytes were evaluated. Genotyping were performed using Illumina Human Exome BeadChip with 241,305 single nucleotide variants (SNVs). The DNA damage levels are consistent with the PM2.5 exposure levels of each cohort. A total of 35 SNVs were consistently associated with DNA damage levels among the three cohorts with pooled P values less than 1.00×10(-3) after adjustment for age, gender, smoking status and PM2.5 exposure levels, of which, 18 SNVs together with gender and PM2.5 exposure levels were independent factors contributing to DNA damage. Gene-based test revealed 3 genes significantly associated with DNA damage levels (P=5.11×10(-3) for POLH, P=2.88×10(-3) for RIT2 and P=2.29×10(-2) for CNTN4). Gene ontology (GO) analyses indicated that the identified variants were significantly enriched in DNA damage response pathway. Our findings highlight the importance of genetic variation as well as personal PM2.5 exposure in modulating individual DNA damage levels. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  20. Direct Index Method of Beam Damage Location Detection Based on Difference Theory of Strain Modal Shapes and the Genetic Algorithms Application

    Directory of Open Access Journals (Sweden)

    Bao Zhenming

    2012-01-01

    Full Text Available Structural damage identification is to determine the structure health status and analyze the test results. The three key problems to be solved are as follows: the existence of damage in structure, to detect the damage location, and to confirm the damage degree or damage form. Damage generally changes the structure physical properties (i.e., stiffness, mass, and damping corresponding with the modal characteristics of the structure (i.e., natural frequencies, modal shapes, and modal damping. The research results show that strain mode can be more sensitive and effective for local damage. The direct index method of damage location detection is based on difference theory, without the modal parameter of the original structure. FEM numerical simulation to partial crack with different degree is done. The criteria of damage location detection can be obtained by strain mode difference curve through cubic spline interpolation. Also the genetic algorithm box in Matlab is used. It has been possible to identify the damage to a reasonable level of accuracy.

  1. Effect of low temperature on radiation-induced genetic damage in Drosophila melanogaster

    International Nuclear Information System (INIS)

    Mazar Barnett, Beatriz

    1992-01-01

    The response of fully mature motile sperm and late spermatids when challenged with X-radiation at 0 o C has been studied in sex-linked recessive lethals, II-III translocations and dominant lethality experiments. At 0 o C a significant increase in both mutagenic and clastogenic damage was detected compared to that obtained at 24 o C. Furthermore, the results of experiments performed with different postirradiation temperatures demonstrate that low temperature during irradiation was the sole factor responsible for the observed increase. In the recessive lethal and translocation tests the response of late spermatids was higher than that shown by motile spermatozoa. As a whole, the results, which are rather similar to data reported on the effects of irradiation in oxygen of the same cell stages, suggest that the low temperature acted as dose-modifying factor. (author). 21 refs.; 6 tabs

  2. FISH as A method for detection of radiation Induced genetic damage

    International Nuclear Information System (INIS)

    Lakatosova, M.; Holeckova, B.

    2006-01-01

    Fluorescence in situ hybridization (FISH) has been considered as a suitable method for rapid and easy detection of chromosome aberrations. In contrast to the standard conventional staining procedure, this technique enables the detection and specification of stable chromosomal re-arrangements, which are compatible with cellular division and thus, they could be transmitted from common ancestral to next cell generations. FISH chromosome - specific painting probes have been effectively applied for the detection of chromosomal damage after exposure to radiation. During last years, several specific fluorescent labeled probes were performed that allowed precise detection of centromeres, sub-telomeres or other regions (sequences) in genome. Our paper deals with describing of different types of FISH probes and their possibilities for application in radiobiology. (authors)

  3. Refinement of Foam Backfill Technology for Expedient Airfield Damage Repair- Phase I: Laboratory Evaluation of Foam Materials

    Science.gov (United States)

    2016-11-01

    specimens before and after unmolding. B) Bottom of specimen following unmolding. C) Crack generated during foam expansion and curing...The Program Manager was Jeb S. Tingle, ERDC-GSL. This work was performed by the Airfields and Pavements Branch (GMA) of the Engineering Systems...airfield damage repair AFCEC U.S. Air Force Civil Engineer Center APB Airfields and Pavements Branch ASTM American Society for Testing and Materials

  4. Diffusion-controlled and creep-mitigated ASR damage via microplane model: II. Material degra- dation, drying, and verification

    OpenAIRE

    Rahimi-Aghdam, Saeed; P. Bažant, Zdenek; Caner, Ferhun Cem

    2016-01-01

    The theory for the material and structural damage due to the alkali-silica reaction (ASR) in concrete is calibrated and validated by finite element fitting of the main test results from the literature. The fracture mechanics aspects, and particularly the localization limiter, are handled by the crack band model. It is shown that the theory can capture the following features quite well: (1) the effects of various loading conditions and stress states on the ASR-induced expansion and it...

  5. Laser-induced damage of materials in bulk, thin-film, and liquid forms

    International Nuclear Information System (INIS)

    Natoli, Jean-Yves; Gallais, Laurent; Akhouayri, Hassan; Amra, Claude

    2002-01-01

    Accurate threshold curves of laser-induced damage (7-ns single shot at 1.064 μm) are measured in bulk and at the surfaces of optical components such as substrates, thin films, multilayers, and liquids. The shapes and the slopes of the curves are related to the spot size and to the densities of the nanodefects that are responsible for damage. First, these densities are reported for bulk substrates. In surfaces and films the recorded extrinsic and intrinsic threshold curves permit the discrimination of the effects of microdefects and nanodefects. In all cases the density of nanocenters is extracted by means of a phenomenological approach. Then we test liquids and mixtures of liquids with controlled defect densities. The results emphasize the agreement between measurement and prediction and demonstrate the validity of the presence of different kinds of nanocenter as the precursors of laser damage

  6. Light ions cyclotron bombardment to simulate fast neutron radiation damage in nuclear materials

    International Nuclear Information System (INIS)

    Segura, E.; Lucki, G.; Aguiar, D.

    1984-01-01

    The applicability and limitations of the use of cyclotron light ions bombardment to simulate the effects of the neutron irradiation are presented. Light ions with energies of about 10 MeV are capable to produce homogeneous damage in specimens suitable for measuring bulk mechanical properties although their low damage rate of 10 -5 dpa.sec -1 limit the dose range to a few dpa. On the other hand, cyclotron alpha particle implantation provides a fast and convenient way of introducing helium with a minimum of side effects so that we can take advantage of this technique to get better understanding of the mechanism by which this insoluble gas produces high temperature embrittlement. Some experimental details such as dimensions and cooling techniques are described. Finally a description of the infrastructure for cyclotron alpha particle implantation and a creep-test facility of the Division of Radiation Damage at IPEN-CNEN/SP are presented. (Author) [pt

  7. Ion-irradiation-induced damage in nuclear materials: Case study of a-SiO2 and MgO

    International Nuclear Information System (INIS)

    Bachiller-Perea, Diana

    2016-01-01

    One of the most important challenges in Physics today is the development of a clean, sustainable, and efficient energy source that can satisfy the needs of the actual and future society producing the minimum impact on the environment. For this purpose, a huge international research effort is being devoted to the study of new systems of energy production; in particular, Generation IV fission reactors and nuclear fusion reactors are being developed. The materials used in these reactors will be subjected to high levels of radiation, making necessary the study of their behavior under irradiation to achieve a successful development of these new technologies. In this thesis two materials have been studied: amorphous silica (a-SiO 2 ) and magnesium oxide (MgO). Both materials are insulating oxides with applications in the nuclear energy industry. High-energy ion irradiations have been carried out at different accelerator facilities to induce the irradiation damage in these two materials; then, the mechanisms of damage have been characterized using principally Ion Beam Analysis (IBA) techniques. One of the challenges of this thesis was to develop the Ion Beam Induced Luminescence or iono-luminescence (which is not a widely known IBA technique) and to apply it to the study of the mechanisms of irradiation damage in materials, proving the power of this technique. For this purpose, the iono-luminescence of three different types of silica (containing different amounts of OH groups) has been studied in detail and used to describe the creation and evolution of point defects under irradiation. In the case of MgO, the damage produced under 1.2 MeV Au + irradiation has been characterized using Rutherford backscattering spectrometry in channeling configuration and X-ray diffraction. Finally, the iono-luminescence of MgO under different irradiation conditions has also been studied.The results obtained in this thesis help to understand the irradiation-damage processes in materials

  8. SIAM CM 09 - The SIAM method for applying cohesive models to the damage behaviour of engineering materials and structures

    International Nuclear Information System (INIS)

    Scheider, Ingo; Cornec, Alfred; Schwalbe, Karl-Heinz

    2009-01-01

    This document provides guidance on the determination of damage and fracture of ductile metallic materials and structures made thereof, based mainly on experience obtained at GKSS. The method used for the fracture prediction is the cohesive model, in which material separation is represented by interface elements and their constitutive behaviour, the so-called traction-separation law, in the framework of finite elements. Several traction-separation laws are discussed, some of which are already implemented in commercial finite element codes and therefore easy applicable. Methods are described for the determination of the cohesive parameters, using a hybrid experimental/numerical approach. (orig.)

  9. SIAM CM 09 - The SIAM method for applying cohesive models to the damage behaviour of engineering materials and structures

    Energy Technology Data Exchange (ETDEWEB)

    Scheider, Ingo; Cornec, Alfred [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Materialforschung; Schwalbe, Karl-Heinz

    2009-12-19

    This document provides guidance on the determination of damage and fracture of ductile metallic materials and structures made thereof, based mainly on experience obtained at GKSS. The method used for the fracture prediction is the cohesive model, in which material separation is represented by interface elements and their constitutive behaviour, the so-called traction-separation law, in the framework of finite elements. Several traction-separation laws are discussed, some of which are already implemented in commercial finite element codes and therefore easy applicable. Methods are described for the determination of the cohesive parameters, using a hybrid experimental/numerical approach. (orig.)

  10. Influence of some exo nucleases in response to the induced genetic damage in Escherichia coli by alpha radiation

    International Nuclear Information System (INIS)

    Aguilar M, M.

    2005-01-01

    Within the strategies with those that E. coli counts to overcome to the genetic damage there is the SOS response, a group of genes that participate in repair and/or tolerance that it confers to the bacteria major opportunities of surviving. These genes are repressed and its only are expressed when it happens genetic damage. So that this system is activated it is necessary that DNA of a band exists and in this sense the double ruptures (RDB) its are not able to induce this response unless there is a previous processing. In stumps with defects in certain genes that have to do with repair of RDB (as recO, recJ and xonA) the activity of SOS is smaller than in a wild stump what suggests that these participate in the previous processes to the activation of the response. The ionizing radiation produce among other many lesions, RDB in greater or smaller proportion, depending on the ionization capacity. A parameter to evaluate this capacity is the lineal energy transfer (LET), defined as the average energy given by unit of distance travelled. In general the LET of the corpuscular radiations is a lot but high that of the electromagnetic one, for what produces bigger quantity of ionizations inside a restricted zone and it increases by this way the probability that RDB has been generated. This work has for object to infer the participation of xonA and recJ in this response and to evaluate the damage produced by ionizing radiation of different LET (alpha particles of different energies) in a stump with all the functional repair mechanisms. Its were considered two parameters: the survival and the activity of SOS evaluated by means of the chromo test. The results indicate that the activity of these exo nucleases is necessary for the repair of RDB as well as for the processing of lesions foresaw to the activation of SOS. As for the treatment with alphas of different energies is observed that so much the survival like the activity of SOS vary as the LET of the radiation changes

  11. Concrete Materials with Ultra-High Damage Resistance and Self- Sensing Capacity for Extended Nuclear Fuel Storage Systems

    Energy Technology Data Exchange (ETDEWEB)

    Li, Mo [Univ. of California, Irvine, CA (United States); Nakshatrala, Kalyana [Univ. of Houston, TX (United States); William, Kasper [Univ. of Houston, TX (United States); Xi, Yungping [Univ. of Colorado, Boulder, CO (United States)

    2017-02-08

    The objective of this project is to develop a new class of multifunctional concrete materials (MSCs) for extended spent nuclear fuel (SNF) storage systems, which combine ultra-high damage resistance through strain-hardening behavior with distributed multi-dimensional damage self-sensing capacity. The beauty of multifunctional concrete materials is two-fold: First, it serves as a major material component for the SNF pool, dry cask shielding and foundation pad with greatly improved resistance to cracking, reinforcement corrosion, and other common deterioration mechanisms under service conditions, and prevention from fracture failure under extreme events (e.g. impact, earthquake). This will be achieved by designing multiple levels of protection mechanisms into the material (i.e., ultrahigh ductility that provides thousands of times greater fracture energy than concrete and normal fiber reinforced concrete; intrinsic cracking control, electrochemical properties modification, reduced chemical and radionuclide transport properties, and crack-healing properties). Second, it offers capacity for distributed and direct sensing of cracking, strain, and corrosion wherever the material is located. This will be achieved by establishing the changes in electrical properties due to mechanical and electrochemical stimulus. The project will combine nano-, micro- and composite technologies, computational mechanics, durability characterization, and structural health monitoring methods, to realize new MSCs for very long-term (greater than 120 years) SNF storage systems.

  12. Genetic similarity among commercial oil palm materials based on microsatellite markers

    Directory of Open Access Journals (Sweden)

    Diana Arias

    2012-08-01

    Full Text Available Microsatellite markers are used to determine genetic similarities among individuals and might be used in various applications in breeding programs. For example, knowing the genetic similarity relationships of commercial planting materials helps to better understand their responses to environmental, agronomic and plant health factors. This study assessed 17 microsatellite markers in 9 crosses (D x P of Elaeis guineensis Jacq. from various commercial companies in Malaysia, France, Costa Rica and Colombia, in order to find possible genetic differences and/or similarities. Seventy-seven alleles were obtained, with an average of 4.5 alleles per primer and a range of 2-8 amplified alleles. The results show a significant reduction of alleles, compared to the number of alleles reported for wild oil palm populations. The obtained dendrogram shows the formation of two groups based on their genetic similarity. Group A, with ~76% similarity, contains the commercial material of 3 codes of Deli x La Mé crosses produced in France and Colombia, and group B, with ~66% genetic similarity, includes all the materials produced by commercial companies in Malaysia, France, Costa Rica and Colombia

  13. Articulation of Native Cartilage Against Different Femoral Component Materials. Oxidized Zirconium Damages Cartilage Less Than Cobalt-Chrome.

    Science.gov (United States)

    Vanlommel, Jan; De Corte, Ronny; Luyckx, Jean Philippe; Anderson, Melissa; Labey, Luc; Bellemans, Johan

    2017-01-01

    Oxidized zirconium (OxZr) is produced by thermally driven oxidization creating an oxidized surface with the properties of a ceramic at the top of the Zr metal substrate. OxZr is much harder and has a lower coefficient of friction than cobalt-chrome (CoCr), both leading to better wear characteristics. We evaluated and compared damage to the cartilage of porcine patella plugs, articulating against OxZr vs CoCr. Our hypothesis was that, owing to its better wear properties, OxZr would damage cartilage less than CoCr. If this is true, OxZr might be a better material for the femoral component during total knee arthroplasty if the patella is not resurfaced. Twenty-one plugs from porcine patellae were prepared and tested in a reciprocating pin-on-disk machine while lubricated with bovine serum and under a constant load. Three different configurations were tested: cartilage-cartilage as the control group, cartilage-OxZr, and cartilage-CoCr. Macroscopic appearance, cartilage thickness, and the modified Mankin score were evaluated after 400,000 wear cycles. The control group showed statistically significant less damage than plugs articulating against both other materials. Cartilage plugs articulating against OxZr were statistically significantly less damaged than those articulating against CoCr. Although replacing cartilage by an implant always leads to deterioration of the cartilage counterface, OxZr results in less damage than CoCr. The use of OxZr might thus be preferable to CoCr in case of total knee arthroplasty without patella resurfacing. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Neural-Network-Biased Genetic Algorithms for Materials Design: Evolutionary Algorithms That Learn.

    Science.gov (United States)

    Patra, Tarak K; Meenakshisundaram, Venkatesh; Hung, Jui-Hsiang; Simmons, David S

    2017-02-13

    Machine learning has the potential to dramatically accelerate high-throughput approaches to materials design, as demonstrated by successes in biomolecular design and hard materials design. However, in the search for new soft materials exhibiting properties and performance beyond those previously achieved, machine learning approaches are frequently limited by two shortcomings. First, because they are intrinsically interpolative, they are better suited to the optimization of properties within the known range of accessible behavior than to the discovery of new materials with extremal behavior. Second, they require large pre-existing data sets, which are frequently unavailable and prohibitively expensive to produce. Here we describe a new strategy, the neural-network-biased genetic algorithm (NBGA), for combining genetic algorithms, machine learning, and high-throughput computation or experiment to discover materials with extremal properties in the absence of pre-existing data. Within this strategy, predictions from a progressively constructed artificial neural network are employed to bias the evolution of a genetic algorithm, with fitness evaluations performed via direct simulation or experiment. In effect, this strategy gives the evolutionary algorithm the ability to "learn" and draw inferences from its experience to accelerate the evolutionary process. We test this algorithm against several standard optimization problems and polymer design problems and demonstrate that it matches and typically exceeds the efficiency and reproducibility of standard approaches including a direct-evaluation genetic algorithm and a neural-network-evaluated genetic algorithm. The success of this algorithm in a range of test problems indicates that the NBGA provides a robust strategy for employing informatics-accelerated high-throughput methods to accelerate materials design in the absence of pre-existing data.

  15. Topical calcitriol protects from UV-induced genetic damage but suppresses cutaneous immunity in humans.

    Science.gov (United States)

    Damian, Diona L; Kim, Young Jin; Dixon, Katie M; Halliday, Gary M; Javeri, Arash; Mason, Rebecca S

    2010-08-01

    Calcitriol, the biologically active form of vitamin D, has been reported to cause both suppressive and protective immune effects in mice. Its immune effects in vivo in humans are unclear. We investigated the in vivo effects of topical calcitriol on minimal erythema dose and skin immune responses in healthy volunteers. We found that calcitriol did not protect from ultraviolet (UV)-induced erythema (sunburn) when applied either 24 h before or immediately after irradiation, although it decreased the density of sunburn cells and thymine dimers seen on biopsy when applied 24 h before and again immediately after irradiation. Using the Mantoux reaction as a model of skin immunity, we found that topical calcitriol applied at high total doses reduced the Mantoux responses of nearby untreated, unirradiated skin, suggesting a para-local or systemic immunosuppressive effect not observed with lower calcitriol doses. We then measured UV-induced suppression of Mantoux reactions at vehicle-treated sites and sites treated with low-dose calcitriol, and found that calcitriol neither reduced nor enhanced UV-induced immunosuppression. Despite calcitriol reducing UV-induced DNA damage, which should protect the immune system, it has immunosuppressive effects in our model which may help to explain the efficacy of analogues such as calcipotriol in the treatment of psoriasis.

  16. Numerical study of the EDZ by a thermo-hydro-mechanical damage model dedicated to unsaturated geo-materials

    International Nuclear Information System (INIS)

    Arson, Chloe; Gatmiri, Behrouz

    2010-01-01

    involved in the transfer model in the intact state. A specific algorithm has been written in order to implement the 'THHMD' model in 'Θ-Stock' Finite Element code. In the brittle domain, the increment of damage-associated stress has a non-linear expression, and is thus computed iteratively. The final algorithm encompasses three interwoven loops, and two convergence criteria. Due to the couplings between the constitutive laws, the computation of the residual vector requires specific dynamic storage variables. Simulations of laboratory tests have already provided a numerical validation of the mechanical aspect of the model. This article presents the results of more complex simulations, aimed at studying the effects of a decreasing thermal loading on an unsaturated host geo-material. The numerical response of the algorithm is first checked in the elastic domain, by comparing the numerical results to experimental data. Parametric studies are then performed with the same materials endowed with non zero damage parameter. This approach enables the study of damage trends in various loading conditions, with various parameter combinations. A heating laboratory test performed on unsaturated bentonite samples has been simulated with the 'THHMD' model. The satisfactory results obtained in elasticity in the experimental conditions justify a parametric study on damage. The rigidity to mechanical tensile strains (g M ) has been varied for a given heating power on the one hand, and the power of the heating source has been varied with a fixed gM parameter on the other hand. In both cases, damage trends are in full agreement with the physical expectations. In accordance with the assumptions of the model, the thermal loading generates isotropic tensile strains, and consequently, isotropic damage. Damage grows with the rigidity to tensile strains g M and with the heating power. An in situ heating test has been reproduced by a one-dimensional axisymmetric

  17. A Mechanical, Microstructural, and Damage Study of Various Tailor Hot Stamped Material Conditions Consisting of Martensite, Bainite, Ferrite, and Pearlite

    Science.gov (United States)

    Bardelcik, Alexander; Vowles, Caryn J.; Worswick, Michael J.

    2018-02-01

    This paper examines the mechanical, microstructural, and damage characteristics of five different material conditions that were created using the tailored hot stamping process with in-die heating. The tailored material conditions, TMC1 to TMC5 (softest-hardest), were created using die temperatures ranging from 700 °C to 400 °C, respectively. The tensile strength (and total elongation) ranged from 615 MPa (0.24) for TMC1 to 1122 MPa (0.11) for TMC5. TMC3 and TMC4 exhibited intermediate strength levels, with almost no increase in total elongation relative to TMC5. FE-SEM microscopy was used to quantify the mixed-phase microstructures, which ranged in volume fractions of ferrite, pearlite, bainite, and martensite. High-resolution optical microscopy was used to quantify void accumulation and showed that the total void area fraction at 0.60 thickness strain was low for TMC1 and TMC5 ( 0.09 pct) and highest for TMC3 (0.31 pct). Damage modes were characterized and revealed that the poor damage behavior of TMC3 (martensite/bainite/ferrite composition) was a result of small martensitic grains forming at grain boundaries and grain boundary junctions, which facilitated void nucleation as shown by the highest measured void density for this particular material condition. The excellent ductility of TMC1 was a result of a large grained ferritic/pearlitic microstructure that was less susceptible to void nucleation and growth. Large titanium nitride (TiN) inclusions were observed in all of the tailored material conditions and it was shown that they noticeably contributed to the total void accumulation, specifically for the TMC3 and TMC4 material conditions.

  18. A Mechanical, Microstructural, and Damage Study of Various Tailor Hot Stamped Material Conditions Consisting of Martensite, Bainite, Ferrite, and Pearlite

    Science.gov (United States)

    Bardelcik, Alexander; Vowles, Caryn J.; Worswick, Michael J.

    2018-04-01

    This paper examines the mechanical, microstructural, and damage characteristics of five different material conditions that were created using the tailored hot stamping process with in-die heating. The tailored material conditions, TMC1 to TMC5 (softest-hardest), were created using die temperatures ranging from 700 °C to 400 °C, respectively. The tensile strength (and total elongation) ranged from 615 MPa (0.24) for TMC1 to 1122 MPa (0.11) for TMC5. TMC3 and TMC4 exhibited intermediate strength levels, with almost no increase in total elongation relative to TMC5. FE-SEM microscopy was used to quantify the mixed-phase microstructures, which ranged in volume fractions of ferrite, pearlite, bainite, and martensite. High-resolution optical microscopy was used to quantify void accumulation and showed that the total void area fraction at 0.60 thickness strain was low for TMC1 and TMC5 ( 0.09 pct) and highest for TMC3 (0.31 pct). Damage modes were characterized and revealed that the poor damage behavior of TMC3 (martensite/bainite/ferrite composition) was a result of small martensitic grains forming at grain boundaries and grain boundary junctions, which facilitated void nucleation as shown by the highest measured void density for this particular material condition. The excellent ductility of TMC1 was a result of a large grained ferritic/pearlitic microstructure that was less susceptible to void nucleation and growth. Large titanium nitride (TiN) inclusions were observed in all of the tailored material conditions and it was shown that they noticeably contributed to the total void accumulation, specifically for the TMC3 and TMC4 material conditions.

  19. Research status on radiation damage in nuclear materials and recommendations for IAEA activities. Technical report

    International Nuclear Information System (INIS)

    Caro, Alfredo; Caro, Magdalena

    2002-03-01

    This report addresses the synergy between the continuous progress of parallel computing and the spectacular advances in the theoretical framework that describes materials. Together, they contributed to significantly advance our comprehension of materials properties like mechanical behavior. It also highlights its impact on nuclear technology, as it provides physical insight into the complex processes responsible for the degradation of structural materials under neutron irradiation

  20. Chesapeake Bay fish-osprey (Pandion haliaetus) food chain: Evaluation of contaminant exposure and genetic damage.

    Science.gov (United States)

    Lazarus, Rebecca S; Rattner, Barnett A; McGowan, Peter C; Hale, Robert C; Karouna-Renier, Natalie K; Erickson, Richard A; Ottinger, Mary Ann

    2016-06-01

    From 2011 to 2013, a large-scale ecotoxicological study was conducted in several Chesapeake Bay (USA) tributaries (Susquehanna River and flats, the Back, Baltimore Harbor/Patapsco Rivers, Anacostia/ middle Potomac, Elizabeth and James Rivers) and Poplar Island as a mid-Bay reference site. Osprey (Pandion haliaetus) diet and the transfer of contaminants from fish to osprey eggs were evaluated. The most bioaccumulative compounds (biomagnification factor > 5) included p,p'-dichlorodiphenyldichloroethylene (DDE), total polychlorinated biphenyls (PCBs), total polybrominated diphenyl ethers (PBDEs), and bromodiphenyl ether (BDE) congeners 47, 99, 100, and 154. This analysis suggested that alternative brominated flame retardants and other compounds (methoxytriclosan) are not appreciably biomagnifying. A multivariate analysis of similarity indicated that major differences in patterns among study sites were driven by PCB congeners 105, 128, 156, 170/190, and 189, and PBDE congeners 99 and 209. An integrative redundancy analysis showed that osprey eggs from Baltimore Harbor/Patapsco River and the Elizabeth River had high residues of PCBs and p,p'-DDE, with PBDEs making a substantial contribution to overall halogenated contamination on the Susquehanna and Anacostia/middle Potomac Rivers. The redundancy analysis also suggested a potential relation between PBDE residues in osprey eggs and oxidative DNA damage in nestling blood samples. The results also indicate that there is no longer a discernible relation between halogenated contaminants in osprey eggs and their reproductive success in Chesapeake Bay. Osprey populations are thriving in much of the Chesapeake, with productivity rates exceeding those required to sustain a stable population. Environ Toxicol Chem 2016;35:1560-1575. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US Government work and, as such, is in the public domain in the United States of America. Published 2016 Wiley

  1. Chesapeake Bay fish–osprey (Pandion haliaetus) food chain: Evaluation of contaminant exposure and genetic damage

    Science.gov (United States)

    Lazarus, Rebecca S.; Rattner, Barnett A.; McGowan, Peter C.; Hale, Robert C.; Karouna-Reiner, Natalie K.; Erickson, Richard A.; Ottinger, Mary Ann

    2016-01-01

    From 2011 to 2013, a large-scale ecotoxicological study was conducted in several Chesapeake Bay (USA) tributaries (Susquehanna River and flats, the Back, Baltimore Harbor/Patapsco Rivers, Anacostia/ middle Potomac, Elizabeth and James Rivers) and Poplar Island as a mid-Bay reference site. Osprey (Pandion haliaetus) diet and the transfer of contaminants from fish to osprey eggs were evaluated. The most bioaccumulative compounds (biomagnification factor > 5) included p,p′-dichlorodiphenyldichloroethylene (DDE), total polychlorinated biphenyls (PCBs), total polybrominated diphenyl ethers (PBDEs), and bromodiphenyl ether (BDE) congeners 47, 99, 100, and 154. This analysis suggested that alternative brominated flame retardants and other compounds (methoxytriclosan) are not appreciably biomagnifying. A multivariate analysis of similarity indicated that major differences in patterns among study sites were driven by PCB congeners 105, 128, 156, 170/190, and 189, and PBDE congeners 99 and 209. An integrative redundancy analysis showed that osprey eggs from Baltimore Harbor/Patapsco River and the Elizabeth River had high residues of PCBs and p,p′-DDE, with PBDEs making a substantial contribution to overall halogenated contamination on the Susquehanna and Anacostia/middle Potomac Rivers. The redundancy analysis also suggested a potential relation between PBDE residues in osprey eggs and oxidative DNA damage in nestling blood samples. The results also indicate that there is no longer a discernible relation between halogenated contaminants in osprey eggs and their reproductive success in Chesapeake Bay. Osprey populations are thriving in much of the Chesapeake, with productivity rates exceeding those required to sustain a stable population.

  2. Damage detection in carbon composite material typical of wind turbine blades using auto-associative neural networks

    Science.gov (United States)

    Dervilis, N.; Barthorpe, R. J.; Antoniadou, I.; Staszewski, W. J.; Worden, K.

    2012-04-01

    The structure of a wind turbine blade plays a vital role in the mechanical and structural operation of the turbine. As new generations of offshore wind turbines are trying to achieve a leading role in the energy market, key challenges such as a reliable Structural Health Monitoring (SHM) of the blades is significant for the economic and structural efficiency of the wind energy. Fault diagnosis of wind turbine blades is a "grand challenge" due to their composite nature, weight and length. The damage detection procedure involves additional difficulties focused on aerodynamic loads, environmental conditions and gravitational loads. It will be shown that vibration dynamic response data combined with AANNs is a robust and powerful tool, offering on-line and real time damage prediction. In this study the features used for SHM are Frequency Response Functions (FRFs) acquired via experimental methods based on an LMS system by which identification of mode shapes and natural frequencies is accomplished. The methods used are statistical outlier analysis which allows a diagnosis of deviation from normality and an Auto-Associative Neural Network (AANN). Both of these techniques are trained by adopting the FRF data for normal and damage condition. The AANN is a method which has not yet been widely used in the condition monitoring of composite materials of blades. This paper is trying to introduce a new scheme for damage detection, localisation and severity assessment by adopting simple measurements such as FRFs and exploiting multilayer neural networks and outlier novelty detection.

  3. Multiscale analysis: a way to investigate laser damage precursors in materials for high power applications at nanosecond pulse duration

    Science.gov (United States)

    Natoli, J. Y.; Wagner, F.; Ciapponi, A.; Capoulade, J.; Gallais, L.; Commandré, M.

    2010-11-01

    The mechanism of laser induced damage in optical materials under high power nanosecond laser irradiation is commonly attributed to the presence of precursor centers. Depending on material and laser source, the precursors could have different origins. Some of them are clearly extrinsic, such as impurities or structural defects linked to the fabrication conditions. In most cases the center size ranging from sub-micrometer to nanometer scale does not permit an easy detection by optical techniques before irradiation. Most often, only a post mortem observation of optics permits to proof the local origin of breakdown. Multi-scale analyzes by changing irradiation beam size have been performed to investigate the density, size and nature of laser damage precursors. Destructive methods such as raster scan, laser damage probability plot and morphology studies permit to deduce the precursor densities. Another experimental way to get information on nature of precursors is to use non destructive methods such as photoluminescence and absorption measurements. The destructive and non destructive multiscale studies are also motivated for practical reasons. Indeed LIDT studies of large optics as those used in LMJ or NIF projects are commonly performed on small samples and with table top lasers whose characteristics change from one to another. In these conditions, it is necessary to know exactly the influence of the different experimental parameters and overall the spot size effect on the final data. In this paper, we present recent developments in multiscale characterization and results obtained on optical coatings (surface case) and KDP crystal (bulk case).

  4. Materials properties utilization in a cumulative mechanical damage function for LMFBR fuel pin failure analysis

    International Nuclear Information System (INIS)

    Jacobs, D.C.

    1977-01-01

    An overview is presented of one of the fuel-pin analysis techniques used in the CRBRP program, the cumulative mechanical damage function. This technique, as applied to LMFBR's, was developed along with the majority of models used to describe the mechanical properties and environmental behavior of the cladding (i.e., 20 percent cold-worked, 316 stainless steel). As it relates to fuel-pin analyses the Cumulative Mechanical Damage Function (CDF) continually monitors cladding integrity through steady state and transient operation; it is a time dependent function of temperature and stress which reflects the effects of both the prior mechanical history and the variations in mechanical properties caused by exposure to the reactor environment

  5. Modulation of Radiation-Induced Genetic Damage by HCMV in Peripheral Blood Lymphocytes from a Brain Tumor Case-Control Study

    Energy Technology Data Exchange (ETDEWEB)

    Rourke, Elizabeth A.; Lopez, Mirtha S.; Monroy, Claudia M. [Department of Epidemiology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030 (United States); Scheurer, Michael E. [Department of Pediatrics and Dan L. Duncan Cancer Center, The Baylor College of Medicine, Houston, TX 77030 (United States); Etzel, Carol J. [Department of Epidemiology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030 (United States); Albrecht, Thomas [Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, TX 77555 (United States); Bondy, Melissa L.; El-Zein, Randa A., E-mail: relzein@mdanderson.org [Department of Epidemiology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030 (United States)

    2010-04-12

    Human cytomegalovirus (HCMV) infection occurs early in life and viral persistence remains through life. An association between HCMV infection and malignant gliomas has been reported, suggesting that HCMV may play a role in glioma pathogenesis and could facilitate an accrual of genotoxic damage in the presence of γ-radiation; an established risk factor for gliomas. We tested the hypothesis that HCMV infection modifies the sensitivity of cells to γ-radiation-induced genetic damage. We used peripheral blood lymphocytes (PBLs) from 110 glioma patients and 100 controls to measure the level of chromosome damage and cell death. We evaluated baseline, HCMV-, γ-radiation and HCMV + γ-radiation induced genetic instability with the comprehensive Cytokinesis-Blocked Micronucleus Cytome (CBMN-CYT). HCMV, similar to radiation, induced a significant increase in aberration frequency among cases and controls. PBLs infected with HCMV prior to challenge with γ-radiation led to a significant increase in aberrations as compared to baseline, γ-radiation and HCMV alone. With regards to apoptosis, glioma cases showed a lower percentage of induction following in vitro exposure to γ-radiation and HCMV infection as compared to controls. This strongly suggests that, HCMV infection enhances the sensitivity of PBLs to γ-radiation-induced genetic damage possibly through an increase in chromosome damage and decrease in apoptosis.

  6. Genetic Deletion and Pharmacological Inhibition of PI3Kγ Reduces Neutrophilic Airway Inflammation and Lung Damage in Mice with Cystic Fibrosis-Like Lung Disease

    Directory of Open Access Journals (Sweden)

    Maria Galluzzo

    2015-01-01

    Full Text Available Purpose. Neutrophil-dominated airway inflammation is a key feature of progressive lung damage in cystic fibrosis (CF. Thus, reducing airway inflammation is a major goal to prevent lung damage in CF. However, current anti-inflammatory drugs have shown several limits. PI3Kγ plays a pivotal role in leukocyte recruitment and activation; in the present study we determined the effects of genetic deletion and pharmacologic inhibition of PI3Kγ on airway inflammation and structural lung damage in a mouse model of CF lung disease. Methods. βENaC overexpressing mice (βENaC-Tg were backcrossed with PI3Kγ-deficient (PI3KγKO mice. Tissue damage was assessed by histology and morphometry and inflammatory cell number was evaluated in bronchoalveolar lavage fluid (BALF. Furthermore, we assessed the effect of a specific PI3Kγ inhibitor (AS-605240 on inflammatory cell number in BALF. Results. Genetic deletion of PI3Kγ decreased neutrophil numbers in BALF of PI3KγKO/βENaC-Tg mice, and this was associated with reduced emphysematous changes. Treatment with the PI3Kγ inhibitor AS-605240 decreased the number of neutrophils in BALF of βENaC-Tg mice, reproducing the effect observed with genetic deletion of the enzyme. Conclusions. These results demonstrate the biological efficacy of both genetic deletion and pharmacological inhibition of PI3Kγ in reducing chronic neutrophilic inflammation in CF-like lung disease in vivo.

  7. Evaluation of the potential inhibitor of Ix (Pp-Ix) protoporphyrin of the genetic damage induced by gamma rays administered to different dose reasons in Drosophila melanogaster

    International Nuclear Information System (INIS)

    Flores A, J. A.

    2016-01-01

    Ionizing radiation can damage in DNA directly or indirectly by free radicals (Rl), characterized by unstable and highly reactive. To avoid damage by Rl the cell has endogenous antioxidants such as Sod, Cat, GSH or exogenous as some vitamins, but if with these mechanisms does not reach the cell homeostasis, the consequence may be the generation of chronic-disease degenerative such as cancer. This study was conducted in order to test the inhibitory role of Rl protoporphyrin Ix (Pp-Ix), induced by 20 Gy of gamma rays administered at different dose ratios using the assay of somatic mutation and recombination in the Drosophila wing. The results indicated that 20 Gy delivered at a rate of low dose (6.659 Gy/h), caused elevated frequencies of genetic damage (p <0.001), compared with those that induced a high dose reason (1111.42 Gy/h) in larvae of 48 h old. The difference is probably due to an indirect damage by Rl; when this hypothesis was approved with the possible inhibitor role of Pp-Ix (0.69 m M), damage was increased with the two reasons of tested doses. This result may be due to: 1) the Pp-Ix is not a good inhibitor of Rl, 2) the difference in the frequency of mutation found with both dose reasons, not due to Rl so that this compound did not reduce the genetic damage, and 3) that Pp-Ix acts as pro oxidant. (Author)

  8. Matrix damage helaing in fiber reinforced composite materials containing embedded active and passive wires

    NARCIS (Netherlands)

    Bor, T.C.; Warnet, L.L.; Akkerman, R.; van der Zwaag, Sybrand; Brinkman, E.

    2015-01-01

    Continuous fiber reinforced composite materials are susceptible to matrix cracking and delamination upon impact. Active and passive wires can be embedded within the composite material to support the healing behavior. Upon a local heating stimulus the wires, oriented mostly in the out-of-plane

  9. Consultants Group Meeting on Genetic Sexing and Population Genetics of Screwworms. Working Material

    International Nuclear Information System (INIS)

    2000-01-01

    A Thematic Plan on SIT for Screwworms developed in 1999 by IPC and TC identified certain R and D bottlenecks to the expansion of this technology into new agricultural areas. This consultant's meeting was held to review these conclusions and to advise the Agency on the need, or otherwise, of initiating a CRP to address the bottlenecks identified in the Thematic Plan. In 2001 it is expected that the New World Screwworm, Cochliomyia hominivorax, will have been eradicated from all of Central America, including Panama where a sterile release barrier will be established to prevent re-invasion from South America. This barrier will need to be maintained indefinitely with its associated costs. The use of an all-male strain in the production facility would have very positive impact on the cost/benefit analysis of the programme. The Director of the Screwworm Programme in Central America made this point very strongly during the Thematic Plan discussions and at a subsequent technical meeting in Tuxtla Gutierrez. Interest to expand the programme into South America is now being shown by certain countries in the region where the economic feasibility of implementing an SIT programme might depend on producing sterile flies more economically and here again the use of a genetic sexing strain could play an important role. For the Old World Screwworm, Chrysomya bezziana the Australian authorities have just completed a successful small field trial of the SIT in Malaysia and it is proposed that more extensive field tests be carried out in the region. For both the New World Screwworm in South America and the Old World Screwworm, in Asia there is virtually no information regarding the population structure in relation to the implementation of an SIT programme. Is the Old World Screwworm a single species over its very wide distribution and are the populations of New World Screwworm in South America the same as in Central America and related to each other? Are the populations isolated? These

  10. From Damage to Delamination in Nonlinearly Elastic Materials at Small Strains

    Czech Academy of Sciences Publication Activity Database

    Mielke, A.; Roubíček, Tomáš; Thomas, M.

    2012-01-01

    Roč. 109, č. 2 (2012), s. 235-273 ISSN 0374-3535 R&D Projects: GA MŠk(CZ) 1M06031; GA ČR GAP201/10/0357 Institutional research plan: CEZ:AV0Z20760514 Keywords : rate-independent systems * brittle damage * gamma-convergence for evolutionary systems Subject RIV: BA - General Mathematics Impact factor: 1.038, year: 2012 http://www.springerlink.com/content/a42r23up5t1r4g8w/

  11. Threats to ICF reactor materials: computational simulations of radiation damage induced topological changes in fused silica

    CERN Document Server

    Kubota, A; Stolken, J; Sadigh, B; Reyes, S; Rubia, T D; Latkowski, J F

    2003-01-01

    We have performed molecular dynamics simulations of radiation damage in fused silica. In this study, we discuss the role of successive cascade overlap on the saturation and self-healing of oxygen vacancy defects in the amorphous fused silica network. Furthermore, we present findings on the topological changes in fused silica due to repeated energetic recoil atoms. These topological network modifications consistent with experimental Raman spectroscopic observation on neutron and ion irradiated fused silica are indicators of permanent densification that has also been observed experimentally.

  12. Damaging process of graphite - new model and its impact on degradation of materials performance

    International Nuclear Information System (INIS)

    Tanabe, T.; Muto, S.

    1999-01-01

    The most widely accepted model for development of defect structure in neutron irradiated graphite has been such that following the first production of a pair of an interstitial and vacancy, di-interstitials and vacancies are formed and their subsequent growth would result in the production of an interstitial plane or loop in-between the basal planes and vacancy clusters, respectively, which could cause the loss of thermal conductivity and dimensional change. Recently we have claimed that the formation of vacancy clusters and growth of the interstitial planes are not necessarily a unique interpretation of the damaging process. Instead, the damaging process is described by orientational disordering within the basal planes, i.e. fragmentation into small crystallites and rotation of their crystalline axes, change of stacking order and elongation of the interplanar spacing. The orientational disordering within the basal planes proceeds coordinately over a few layers with their layered correlation maintained. This process accompanies changes in bonding nature producing 5 member- and 7 member-atomic rings as appeared in fullerenes. This is so to speak ''self-restoring or reconstruction'' to maintain resonance bonds as strict as possible without the formation of dangling bonds. This paper reviews irradiation effects in graphite such as increase of hydrogen retention, loss of thermal conductivity and dimensional change on the bases of our new model, taking account of the changes of the bonding nature in irradiated graphite. (orig.)

  13. Laser shocks: A tool for experimental simulation of damage into materials

    Science.gov (United States)

    Boustie, M.; Cuq Lelandais, J. P.; Berthe, L.; Ecault, R.

    2012-07-01

    High power laser irradiation of solids results in a strong shock wave propagation, driving very high amplitude pressure loadings with very short durations. These particular characteristics offer the possibility to study the behaviour of matter under extreme dynamic conditions in continuity with what is possible with the conventional generators of shock (launchers of projectiles, explosives). An advantage of laser shocks is a possible recovery of the shocked samples presenting the metallurgical effects of the shock in most cases. We introduce the principle of the laser shock generation, the characterization of these shocks, the principal mechanisms and effects associated with their propagation in the solids. We show how laser shocks can be a laboratory tool for simulating shock effects at ultra high strain rate, providing a high in information experimental layout for validation of damage modelling on an extended strain rate range compared to conventional shock generators. New data have been obtained with ultra short femtosecond range irradiation. Experimental data gathered through post mortem observation, time resolved velocity measurement are shown along with numerical associated simulations, showing the possibility to predict the damage behaviour of metallic targets under extreme strain rate up to 108 s-1̤

  14. Radiation damage of the construction materials, Phase I, Part II specializations

    International Nuclear Information System (INIS)

    Lazarevic, Dj.

    1963-03-01

    This document contains three reports about the visits and training of the experts involved in VISA-2 project to Saclay. All the documents include technical description about methods for fabrication and testing the materials under different irradiation conditions

  15. Self-Healing Structural Materials for Damage Tolerant Aerospace Vehicles: Mechanoresponsive healing polymers

    Data.gov (United States)

    National Aeronautics and Space Administration — Materials that are capable of puncture healing upon impact show great promise for space exploration applications wherein an internal breach caused by micrometeoroid...

  16. Self-sealing of thermal fatigue and mechanical damage in fiber-reinforced composite materials

    Science.gov (United States)

    Moll, Jericho L.

    Fiber reinforced composite tanks provide a promising method of storage for liquid oxygen and hydrogen for aerospace applications. The inherent thermal fatigue of these vessels leads to the formation of microcracks, which allow gas phase leakage across the tank walls. In this dissertation, self-healing functionality is imparted to a structural composite to effectively seal microcracks induced by both mechanical and thermal loading cycles. Two different microencapsulated healing chemistries are investigated in woven glass fiber/epoxy and uni-weave carbon fiber/epoxy composites. Self-healing of mechanically induced damage was first studied in a room temperature cured plain weave E-glass/epoxy composite with encapsulated dicyclopentadiene (DCPD) monomer and wax protected Grubbs' catalyst healing components. A controlled amount of microcracking was introduced through cyclic indentation of opposing surfaces of the composite. The resulting damage zone was proportional to the indentation load. Healing was assessed through the use of a pressure cell apparatus to detect nitrogen flow through the thickness direction of the damaged composite. Successful healing resulted in a perfect seal, with no measurable gas flow. The effect of DCPD microcapsule size (51 microm and 18 microm) and concentration (0--12.2 wt%) on the self-sealing ability was investigated. Composite specimens with 6.5 wt% 51 microm capsules sealed 67% of the time, compared to 13% for the control panels without healing components. A thermally stable, dual microcapsule healing chemistry comprised of silanol terminated poly(dimethyl siloxane) plus a crosslinking agent and a tin catalyst was employed to allow higher composite processing temperatures. The microcapsules were incorporated into a satin weave E-glass fiber/epoxy composite processed at 120°C to yield a glass transition temperature of 127°C. Self-sealing ability after mechanical damage was assessed for different microcapsule sizees (25 microm and 42

  17. RESTORING A DAMAGED 16-YEAR -OLD INSULATING POLYMER CONCRETE DIKE OVERLAY: REPAIR MATERIALS AND TECHNOLOGIES.

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA,T.

    2007-01-01

    The objective of this program was to design and formulate organic polymer-based material systems suitable for repairing and restoring the overlay panels of insulating lightweight polymer concrete (ILPC) from the concrete floor and slope wall of a dike at KeySpan liquefied natural gas (LNG) facility in Greenpoint, Brooklyn, NY, just over sixteen years ago. It also included undertaking a small-scale field demonstration to ensure that the commercial repairing technologies were applicable to the designed and formulated materials.

  18. New concept of damage evaluation method for core internal materials considering radiation induced stress relaxation (1). Experiments and modeling of radiation effects

    International Nuclear Information System (INIS)

    Miwa, Yukio; Kondo, Keietsu; Okubo, Nariaki; Kaji, Yoshiyuki; Tsukada, Takashi

    2009-01-01

    In order to build the new concept of material damage evaluation method, synergistic effect of radiation and residual stress on material degradation was estimated experimentally, and the effect of radiation induced stress relaxation on retardation of material degradation was observed. (author)

  19. Genetic algorithms and genetic programming for multiscale modeling: Applications in materials science and chemistry and advances in scalability

    Science.gov (United States)

    Sastry, Kumara Narasimha

    2007-03-01

    Effective and efficient rnultiscale modeling is essential to advance both the science and synthesis in a, wide array of fields such as physics, chemistry, materials science; biology, biotechnology and pharmacology. This study investigates the efficacy and potential of rising genetic algorithms for rnultiscale materials modeling and addresses some of the challenges involved in designing competent algorithms that solve hard problems quickly, reliably and accurately. In particular, this thesis demonstrates the use of genetic algorithms (GAs) and genetic programming (GP) in multiscale modeling with the help of two non-trivial case studies in materials science and chemistry. The first case study explores the utility of genetic programming (GP) in multi-timescaling alloy kinetics simulations. In essence, GP is used to bridge molecular dynamics and kinetic Monte Carlo methods to span orders-of-magnitude in simulation time. Specifically, GP is used to regress symbolically an inline barrier function from a limited set of molecular dynamics simulations to enable kinetic Monte Carlo that simulate seconds of real time. Results on a non-trivial example of vacancy-assisted migration on a surface of a face-centered cubic (fcc) Copper-Cobalt (CuxCo 1-x) alloy show that GP predicts all barriers with 0.1% error from calculations for less than 3% of active configurations, independent of type of potentials used to obtain the learning set of barriers via molecular dynamics. The resulting method enables 2--9 orders-of-magnitude increase in real-time dynamics simulations taking 4--7 orders-of-magnitude less CPU time. The second case study presents the application of multiobjective genetic algorithms (MOGAs) in multiscaling quantum chemistry simulations. Specifically, MOGAs are used to bridge high-level quantum chemistry and semiempirical methods to provide accurate representation of complex molecular excited-state and ground-state behavior. Results on ethylene and benzene---two common

  20. Creep damage in welds of X 20 CrMoV 12 1 steel. Part 2 - Studies of long term service exposed material and damage data base and calculation of damage distribution and damage resistance; Krypskador i svetsar av X 20 CrMoV 12 1 staal. Etapp 2 - Studier av lingtidspiverkat material och skadedatabas samt berakning av skadefordelning och skadetilighet

    Energy Technology Data Exchange (ETDEWEB)

    Storesund, Jan; Borggreen, Kjeld; Weilin Zang; Nilsson, Henrik; Samuelson, Aake

    2004-09-01

    The present project has been consisted of the following pieces of work on welds of X20 CrMoV 12 1: Analysis of, by use of replica testing, creep damage development in 368 welds in 11 Danish high pressure steam lines with operation up to 200,000 h. Metallographic investigations of four welds from a retired live steam line with approximately 182 000 h in operation. - Evaluation of the influence of the two most common etching methods on the interpretation of creep cavitation. Analysis of the time security of the material, i.e. influence of enhanced temperature or stress on creep life time. Finite element simulations of the creep behaviour of X20 welds where effects of HAZ creep properties, system stresses and degree of multiaxiality in the rupture criterion are studied. In addition a literature study on publications of creep life time in X20 steel was performed in a first, already reported part of the project. The results of the comprehensive replica testing and the metallographic investigations show clear-cut that welds of this material have an excellently long creep life that indeed will reach 200,000 h. The creep damage at that time is in general very limited. The typical creep life for welds of X20 can be evaluated to at least 250,000 h. The reason for that it is not possible to evaluate an even longer creep life is the fact that creep testing and finite element simulations show that creep elongation and creep damage will accelerate considerably later in the creep life than some low alloy steels. In the worst case this acceleration could start already just after 200,000 h. It is also demonstrated that welds of the X20 steel can stand system stresses much better than low alloy steels. Recommendations for how and when inspections and testing of welds of the current material should be performed have been issued. They have been adapted to the findings in the project. The recommendations can, as long as severe damage is absent, allow for longer inspection intervals

  1. Diamond Particle Detector Properties during High Fluence Material Damage Tests and their Future Applications for Machine Protection in the LHC

    CERN Document Server

    Burkart, F; Borburgh, J; Dehning, B; Di Castro, M; Griesmayer, E; Lechner, A; Lendaro, J; Loprete, F; Losito, R; Montesano, S; Schmidt, R; Wollmann, D; Zerlauth, M

    2013-01-01

    Experience with LHC machine protection (MP) during the last three years of operation shows that the MP systems sufficiently protect the LHC against damage in case of failures leading to beam losses with a time constant exceeding 1ms. An unexpected fast beam loss mechanism, called UFOs [1], was observed, which could potentially quench superconducting magnets. For such fast losses, but also for better understanding of slower losses, an improved understanding of the loss distribution within a bunch train is required [2]. Diamond particle detectors with bunch-by-bunch resolution and high dynamic range have been developed and successfully tested in the LHC and in experiments to quantify the damage limits of LHC components. This paper will focus on experience gained in use of diamond detectors. The properties of these detectors were measured during high-fluence material damage tests in CERN’s Hi-RadMat facility. The results will be discussed and compared to the cross-calibration with FLUKA simulations. Future app...

  2. Standard practice for determining damage-Based design Stress for fiberglass reinforced plastic (FRP) materials using acoustic emission

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2006-01-01

    1.1 This practice details procedures for establishing the direct stress and shear stress damage-based design values for use in the damage-based design criterion for materials to be used in FRP vessels and other composite structures. The practice uses data derived from acoustic emission examination of four-point beam bending tests and in-plane shear tests (see ASME Section X, Article RT-8). 1.2 The onset of lamina damage is indicated by the presence of significant acoustic emission during the reload portion of load/reload cycles. "Significant emission" is defined with historic index. 1.3 Units - The values stated in inch-pound units are to be regarded as standard. The values given in brackets are mathematical conversions to SI units which are provided for information only and are not considered standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health pr...

  3. Characterization and Modeling of Neutron and Gamma-Ray Radiation Damage in Silicon Carbide Semi-Conductor Materials and Silica Optical Fibers at Cryogenic Temperature

    Data.gov (United States)

    National Aeronautics and Space Administration — When radiation is incident upon a material, it can knock atoms within the lattice out of their proper positions. However, this damage can often be overcome because...

  4. Neutron spectra calculation in material in order to compute irradiation damage

    International Nuclear Information System (INIS)

    Dupont, C.; Gonnord, J.; Le Dieu de Ville, A.; Nimal, J.C.; Totth, B.

    1982-01-01

    This short presentation will be on neutron spectra calculation methods in order to compute the damage rate formation in irradiated structure. Three computation schemes are used in the French C.E.A.: (1) 3-dimensional calculations using the line of sight attenuation method (MERCURE IV code), the removal cross section being obtained from an adjustment on a 1-dimensional transport calculation with the discrete ordinate code ANISN; (2) 2-dimensional calculations using the discrete ordinates method (DOT 3.5 code), 20 to 30 group library obtained by collapsing the 100 group a library on fluxes computed by ANISN; (3) 3-dimensional calculations using the Monte Carlo method (TRIPOLI system). The cross sections which originally came from UKNDL 73 and ENDF/B3 are now processed from ENDF B IV. (author)

  5. Damage monitoring of aircraft structures made of composite materials using wavelet transforms

    Science.gov (United States)

    Molchanov, D.; Safin, A.; Luhyna, N.

    2016-10-01

    The present article is dedicated to the study of the acoustic properties of composite materials and the application of non-destructive testing methods to aircraft components. A mathematical model of a wavelet transformed signal is presented. The main acoustic (vibration) properties of different composite material structures were researched. Multiple vibration parameter dependencies on the noise reduction factor were derived. The main steps of a research procedure and new method algorithm are presented. The data obtained was compared with the data from a three dimensional laser-Doppler scanning vibrometer, to validate the results. The new technique was tested in the laboratory and on civil aircraft at a training airfield.

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

    International Nuclear Information System (INIS)

    Arnaud, L; Houel, A

    2010-01-01

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

  7. No increases in biomarkers of genetic damage or pathological changes in heart and brain tissues in male rats administered methylphenidate hydrochloride (Ritalin) for 28 days.

    Science.gov (United States)

    Witt, Kristine L; Malarkey, David E; Hobbs, Cheryl A; Davis, Jeffrey P; Kissling, Grace E; Caspary, William; Travlos, Gregory; Recio, Leslie

    2010-01-01

    Following a 2005 report of chromosomal damage in children with attention deficit/hyperactivity disorder (ADHD) who were treated with the commonly prescribed medication methylphenidate (MPH), numerous studies have been conducted to clarify the risk for MPH-induced genetic damage. Although most of these studies reported no changes in genetic damage endpoints associated with exposure to MPH, one recent study (Andreazza et al. [2007]: Prog Neuropsychopharmacol Biol Psychiatry 31:1282-1288) reported an increase in DNA damage detected by the Comet assay in blood and brain cells of Wistar rats treated by intraperitoneal injection with 1, 2, or 10 mg/kg MPH; no increases in micronucleated lymphocyte frequencies were observed in these rats. To clarify these findings, we treated adult male Wistar Han rats with 0, 2, 10, or 25 mg/kg MPH by gavage once daily for 28 consecutive days and measured micronucleated reticulocyte (MN-RET) frequencies in blood, and DNA damage in blood, brain, and liver cells 4 hr after final dosing. Flow cytometric evaluation of blood revealed no significant increases in MN-RET. Comet assay evaluations of blood leukocytes and cells of the liver, as well as of the striatum, hippocampus, and frontal cortex of the brain showed no increases in DNA damage in MPH-treated rats in any of the three treatment groups. Thus, the previously reported observations of DNA damage in blood and brain tissue of rats exposed to MPH for 28 days were not confirmed in this study. Additionally, no histopathological changes in brain or heart, or elevated serum biomarkers of cardiac injury were observed in these MPH-exposed rats. (c) 2009 Wiley-Liss, Inc.

  8. Radiation damage

    CERN Document Server

    Heijne, Erik H M; CERN. Geneva

    1998-01-01

    a) Radiation damage in organic materials. This series of lectures will give an overview of radiation effects on materials and components frequently used in accelerator engineering and experiments. Basic degradation phenomena will be presented for organic materials with comprehensive damage threshold doses for commonly used rubbers, thermoplastics, thermosets and composite materials. Some indications will be given for glass, scintillators and optical fibres. b) Radiation effects in semiconductor materials and devices. The major part of the time will be devoted to treat radiation effects in semiconductor sensors and the associated electronics, in particular displacement damage, interface and single event phenomena. Evaluation methods and practical aspects will be shown. Strategies will be developed for the survival of the materials under the expected environmental conditions of the LHC machine and detectors. I will describe profound revolution in our understanding of black holes and their relation to quantum me...

  9. Correlating TEM images of damage in irradiated materials to molecular dynamics simulations

    International Nuclear Information System (INIS)

    Schaeublin, R.; Caturla, M.-J.; Wall, M.; Felter, T.; Fluss, M.; Wirth, B.D.; Diaz de la Rubia, T.; Victoria, M.

    2002-01-01

    TEM image simulations are used to couple the results from molecular dynamics (MD) simulations to experimental TEM images. In particular we apply this methodology to the study of defects produced during irradiation. MD simulations have shown that irradiation of FCC metals results in a population of vacancies and interstitials forming clusters. The limitation of these simulations is the short time scales available, on the order of 100 s of picoseconds. Extrapolation of the results from these short times to the time scales of the laboratory has been difficult. We address this problem by two methods: we perform TEM image simulations of MD simulations of cascades with an improved technique, to relate defects produced at short time scales with those observed experimentally at much longer time scales. On the other hand we perform in situ TEM experiments of Au irradiated at liquid-nitrogen temperatures, and study the evolution of the produced damage as the temperature is increased to room temperature. We find that some of the defects observed in the MD simulations at short time scales using the TEM image simulation technique have features that resemble those observed in laboratory TEM images of irradiated samples. In situ TEM shows that stacking fault tetrahedra are present at the lowest temperatures and are stable during annealing up to room temperature, while other defect clusters migrate one dimensionally above -100 deg. C. Results are presented here

  10. The materials concept in German light water reactors. A contribution to plant safety, economic performance and damage prevention

    International Nuclear Information System (INIS)

    Ilg, Ulf

    2008-01-01

    Major decisions taken as early as in the planning and construction phases of nuclear power plants may influence overall plant life. Component quality at the beginning of plant life is determined very much also by a balanced inclusion of the 'design, choice of materials, manufacturing and inspection' elements. One example of the holistic treatment of design, choice of material, and manufacture of important safety-related components in pressurized water reactors is the reactor pressure vessel (RPV) in which the ferritic compound tubes, with inside claddings, for the control rod drive nozzles are screwed into the vessel top. Also the choice of Incoloy 800 for the steam generator tubes, and the design of the main coolant pipes with inside claddings as seamless pipe bends / straight pipes with integrated nozzles connected to mixed welds with austenitic pipes are other special design features of the Siemens/KWU plants. A demonstrably high quality standard by international comparison to this day has been exhibited by the austenitic RPV internals of boiling water reactors, which were made of a low-carbon Nb-stabilized austenitic steel grade by optimum manufacturing technologies. The same material is used for backfitting austenitic pipes. Reliable and safe operation of German nuclear power plants has been demonstrated for more than 4 decades. One major element in this performance is the materials concept adopted in Germany also in the interest of damage prevention. (orig.)

  11. Development of damage evaluation method on the brittle materials for constructions using microscopic structural dynamics and probability theory

    International Nuclear Information System (INIS)

    Arai, Taketoshi

    1997-01-01

    The conventional stress analysis evaluation of the ceramic apparatuses is due to a perfect model of continuous mechanical materials. Such approximate and simplified treatment is thought to be unsufficient with the following two reasons. At first, because of changes of materials mechanical properties with manufacturing conditions and presence of limit in experimentalismic understanding, establishment of quantitative guideline for improvement of materials and structures and general understanding of thermo-mechanical property change due to neutron radiation becomes difficult. The second, because of statistical change of mechanical property and others containing fracture condition at various loading types, judgement standard of conventional deterministic evaluation is apt to be conservative and causes inferior performance and economics of the constructions under their using conditions. Therefore, in this study, following two basic approaches are planned; 1) Preparation of material deformation and fracture model considering correlation between microscopic/mesoscopic damage and macroscopic behavior, and 2) Improvement of the finite element method calculation due to parallel treatment for soundness and reliability evaluation of the construction. (G.K.)

  12. Understanding the Femtosecond Laser-Solid Interaction Near and Beyond the Material Damage Threshold

    Science.gov (United States)

    2016-05-23

    insulator ), band gap, and surface morphology (nano/micro-structured surface), and the PIs team has worked synergistically in designing and performing...ambience (air/vacuum/other), polarization and angle of incidence, target solid material conductivity (metal/semiconductor/ insulator ), band gap, and...microscopy technique has been developed in our lab to observe the formation of laser-induced periodic surface structures (LIPSS) from the interaction of a

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

    Science.gov (United States)

    2015-09-01

    with the 16th European Conference on Composite Materials (ECCM-16) (http://www.eccm16.org) at the Hotel Barcelo Renacimiento near the University of...ECCM-16), Seville, Spain, June 24-25, 2014 Hotel Barcelo Renacimiento , ROOM: R10-España 2 TUESDAY, JUNE 24, 2014 Hotel Barcelo Renacimiento , ROOM...WEDNESDAY, JUNE 25, 2014 Hotel Barcelo Renacimiento , ROOM: Andalucia 9-10 SESSION #4 PANEL DISCUSSION Chairs: Ioannis Chasiotis (U. of Illinois at Urbana

  14. Roughness, surface energy, and superficial damages of CAD/CAM materials after surface treatment.

    Science.gov (United States)

    Strasser, Thomas; Preis, Verena; Behr, Michael; Rosentritt, Martin

    2018-02-05

    The aim of this study was to examine the effects of surface pre-treatment on CAD/CAM materials including ceramics, zirconia, resin-infiltrated ceramic, and resin-based composite. Specimens were made of ten CAD/CAM materials (Celtra Duo, Degudent, D; Vita Suprinity, Vita, D; E.max CAD, Ivoclar-Vivadent, FL; E.max ZirCAD, Ivoclar-Vivadent, FL; Vita Enamic, Vita, D; Cerasmart, GC, B; LAVA Ultimate, 3M, D; SHOFU Block HC, SHOFU, US; Grandio Blocs, VOCO, D; BRILLIANT Crios, Coltene, CH) and pretreated to represent clinical procedures (Hf 20 s/5%; phosphoric acid 20 s/37%; Monobond etch and prime (Ivoclar-Vivadent, FL); water-cooled diamond bur (80 μm; 4 μm); Al 2 O 3 -blasting (50 μm/1 bar, 50 μm/2 bar, 120 μm/1 bar, 120 μm/2 bar); untreated; manufacturer's instructions). SEM-analysis (Phenom, FEI, NL) of the surfaces was performed (magnifications ≤ 10,000×). Roughness values R a , R z (KJ 3D, Keyence, J), and surface energy SE (OCA15 plus, SCA20, DataPhysics, D) were determined (statistics: non-parametric Mann-Whitney U test/Kruskal-Wallis test for independent specimen, α = 0.05). Kruskal-Wallis revealed significant (p CAD/CAM materials require individual pre-treatment for optimized and protective surface activation. Cementation is a key factor for clinical success. Given the variety of available CAD/CAM materials, specific procedures are needed.

  15. Nondestructive indication of fatigue damage and residual lifetime in ferromagnetic construction materials

    Czech Academy of Sciences Publication Activity Database

    Tomáš, Ivan; Kovářík, O.; Vértesy, G.; Kadlecová, Jana

    2014-01-01

    Roč. 25, č. 6 (2014), "065601-1"-"065601-10" ISSN 0957-0233. [International Symposium on Measurement Technology and Intelligent Instruments /11./ (ISMTII). Aachen, 01.07.2013-03.07.2013] R&D Projects: GA ČR(CZ) GAP108/12/1872 Institutional support: RVO:68378271 Keywords : fatigue * residual lifetime * magnetic nondestructive evaluation * ferromagnetic construction materials Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.433, year: 2014

  16. Measuring Visual Literacy Skills on Students’ Concept Understanding of Genetic Transfer Material

    Science.gov (United States)

    Fibriana, F.; Pamelasari, S. D.; Aulia, L. S.

    2017-04-01

    Visualization is an important skill for all students majoring in natural sciences. Also, the visual literacy skills (VLS) are essential for Microbiology learning. The lecturer can use the external representations (ERs) to visualize the microorganisms and its microenvironment. One of learning materials which are rather difficult to interpret in microbiology is genetic transfer. In this study, we measure the VLS on students’ concept understanding of genetic transfer material using a simple test. The tests were held before and after the lecture on this topic employing a combination of talking drawing with picture and picture model. The results show that in the beginning, students showed their poor visual literacy. After the lecture, students were able to draw their understanding on the genetic transfer in bacteria. Most students’ visual literacy ability improves in the level of acceptable. In conclusion, the students’ ability was improved in the average amount of conceptual knowledge. This result reveals that some students comprehend in the correct level of ability, meaning that they have a high degree of conceptual (propositional) and visual knowledge.

  17. Primary DNA damage and genetic polymorphisms for CYP1A1, EPHX and GSTM1 in workers at a graphite electrode manufacturing plant

    Directory of Open Access Journals (Sweden)

    Airoldi Luisa

    2007-10-01

    Full Text Available Abstract Background The results of a cross-sectional study aimed to evaluate whether genetic polymorphisms (biomarkers of susceptibility for CYP1A1, EPHX and GSTM1 genes that affect polycyclic aromatic hydrocarbons (PAH activation and detoxification might influence the extent of primary DNA damage (biomarker of biologically effective dose in PAH exposed workers are presented. PAH-exposure of the study populations was assessed by determining the concentration of 1-hydroxypyrene (1OHP in urine samples (biomarker of exposure dose. Methods The exposed group consisted of workers (n = 109 at a graphite electrode manufacturing plant, occupationally exposed to PAH. Urinary 1OHP was measured by HPLC. Primary DNA damage was evaluated by the alkaline comet assay in peripheral blood leukocytes. Genetic polymorphisms for CYP1A1, EPHX and GSTM1 were determined by PCR or PCR/RFLP analysis. Results 1OHP and primary DNA damage were significantly higher in electrode workers compared to reference subjects. Moreover, categorization of subjects as normal or outlier highlighted an increased genotoxic risk OR = 2.59 (CI95% 1.32–5.05 associated to exposure to PAH. Polymorphisms in EPHX exons 3 and 4 was associated to higher urinary concentrations of 1OHP, whereas none of the genotypes analyzed (CYP1A1, EPHX, and GSTM1 had any significant influence on primary DNA damage as evaluated by the comet assay. Conclusion The outcomes of the present study show that molecular epidemiology approaches (i.e. cross-sectional studies of genotoxicity biomarkers can play a role in identifying common genetic risk factors, also attempting to associate the effects with measured exposure data. Moreover, categorization of subjects as normal or outlier allowed the evaluation of the association between occupational exposure to PAH and DNA damage highlighting an increased genotoxic risk.

  18. UHMWPE-based nanocomposite as a material for damaged cartilage replacement

    International Nuclear Information System (INIS)

    Senatov, F.S.; Kopylov, A.N.; Anisimova, N.Yu.; Kiselevsky, M.V.; Maksimkin, A.V.

    2015-01-01

    In the present work dispersion-strengthened nanocomposites based on ultra-high molecular weight polyethylene (UHMWPE) after mechanical activation were studied. Mechanical activation was performed for hardening of the boundaries between the polymer particles, reducing the fusion defects and increasing of wear-resistance. Three types of samples were prepared: UHMWPE, UHMWPE/Al 2 O 3 nanocomposite and UHMWPE/Al 2 O 3 nanocomposite after mechanical activation. UHMWPE/Al 2 O 3 nanocomposites prepared with mechanical activation show the best mechanical properties in compression and higher wear-resistance. UHMWPE/Al 2 O 3 nanocomposites prepared with mechanical activation were chosen for in vivo study by orthotopical transplantation in rats. Animals' activity has been being monitored for 60 days after surgery. No signs of inflammation, cellular infiltration, destruction of material or bone–cartilage defect were found. Implanted sample has not changed its position of implantation, there were no any shifts. Obtained data shows that UHMWPE-based nanocomposite is a promising material for creating bioimplants for cartilage defect replacement. - Highlights: • Mechanical activation of UHMWPE composite leads to changing of fracture mechanism. • Mechanical activation leads to increasing of wear-resistance of UHMWPE composite. • The presence of Al 2 O 3 in grain boundaries of UHMWPE inhibits crack growth. • Complete integration of UHMWPE-based implant in cartilage defect of rat was shown. • UHMWPE/Al 2 O 3 nanocomposite may be recommended for use in cartilage replacement

  19. The use of plastic optical fibres and shape memory alloys for damage assessment and damping control in composite materials

    Science.gov (United States)

    Kuang, K. S. C.; Cantwell, W. J.

    2003-08-01

    This paper reports the use of a plastic fibre sensor for detecting impact damage in carbon fibre epoxy cantilever beams by monitoring their damping response under free vibration loading conditions. The composite beams were impacted at impact energies up to 8 J. The residual strengths and stiffnesses of the damaged laminates were measured in order to relate reductions in their mechanical properties to changes in their damping characteristics. Here, optical fibre sensors were surface bonded to carbon fibre composite beams which were subjected to free vibration tests to monitor their dynamic response. In the second part of this study, Ni-Ti shape memory alloy (SMA) wires were employed to control and modify the damping response of a composite beam. The SMA wires were initially trained to obtain the desired shape when activated. Here, the trained SMA wires were heated locally using a nickel/chromium wire that was wrapped around the trained region of the SMA. By using this method to activate the SMA wire (as opposed to direct electrical heating), it is possible to obtain localized actuation without heating the entire length of the wire. This procedure minimizes any damage to the host material that may result from local heat transfer between the SMA wire and the composite structure. In addition, the reduction in power requirements to achieve SMA activation permits the use of small-size power packs which can in turn lead to a potential weight reduction in weight-critical applications. The findings of this study demonstrate that a trained SMA offers a superior damping capability to that exhibited by an 'as-supplied' flat-annealed wire.

  20. Evaluation of corrosion damage to materials after three years in the Avery Island salt mine

    International Nuclear Information System (INIS)

    Griess, J.C.

    1982-08-01

    The corrosion results obtained from two heated steel pipes that had been buried in a salt mine at Avery Island, Louisiana, for about three years are reported. In addition, weight losses of corrosion specimens of several alloys attached to the outer surfaces of the pipes were also obtained, and the maximum depths of penetration were measured. The greatest attack was noted on carbon steel, particularly when the water content of the salt was high. The maximum penetration rate observed was about 1 mm/year. All other materials tested underwent much less attack than did carbon steel; titanium and Hastelloy C-276 were totally unaffected on both pipes. Minimal attack was also noted on Zircaloy-2 and type 304L stainless steel, whereas E-Brite 26-1 experienced pitting, and, at high temperatures, a more general attack on some areas. 12 figures, 5 tables

  1. Novel Method to Characterize and Model the Multiaxial Constitutive and Damage Response of Energetic Materials.

    Energy Technology Data Exchange (ETDEWEB)

    Kaneshige, Michael J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rabbi, Md Fazle [Univ. of Texas, El Paso, TX (United States); Kaneshige, Michael J. [Univ. of Texas, El Paso, TX (United States); Mach, Robert [Univ. of Texas, El Paso, TX (United States); Catzin, Carlos A. [Univ. of Texas, El Paso, TX (United States); Stewart, Calvin M. [Univ. of Texas, El Paso, TX (United States)

    2017-12-01

    Simulant polymer bonded explosives are widely used to simulate the mechanical response of real energetic materials. In this paper, the fracture resistance of a simulant polymer bo nded explosive (PBX) is experimentally investigated. The simulant is composed of 80 wt.% soda lime glass beads (SLGB) and 20 wt.% high impact Polystyrene 825 (HIPS). Brazilian disk tests are performed to characterize the tensile and compressive properties. Fracture toughness and energy tests are performed in the semi - circular bending (SCB) configuration on 80, 81, 82, and 83 wt % SLGB compositions. Digital image correlation is performed to record the surface displacements and calculate surface strains during testing. The m icromechanical behavior of ductile and brittle fracture are evaluated using digital microscopy and scanning electron microscopy of the fracture surface. It is determined that (i) the manufacturing process produces a credible simulant of PBX properties, and (ii) the SCB test measures fracture resistance with a reasonable coefficient of variation.

  2. The application of methacrylate resin and the derivation as restorative material of damaged tooth tissue

    Directory of Open Access Journals (Sweden)

    Adioro Soetojo

    2007-12-01

    Full Text Available The application of methacrylate resin and the derivation (composite resin and dentin bonding in clinical conservative dentistry has been widely developed. This material could be used to restore class I-V cavity with good aesthetic due to the compatible color with tooth. Composite resin adhesion hydrophobically in enamel that is due to mechanic retention in the form of resin tags which penetrates into enamel porosity. Meanwhile hydrophilic dentin bonding adhesion due to the chemical reaction between functional groups of amino collagen with carbonyl in dentin bonding forming amide binding. In addition mechanical retention in which dentin bonding penetrating into nano inter fibrilar cavity then polymerized. The success of methacrylate resin adhesion restoration is decided by enamel porosity, wetting character of resin, wetting contact angle, good etching acid, optimal humidity of tooth surface, the accuracy of dentist during filling is done etc.

  3. UHMWPE-based nanocomposite as a material for damaged cartilage replacement

    Energy Technology Data Exchange (ETDEWEB)

    Senatov, F.S., E-mail: Senatov@misis.ru [National University of Science and Technology “MISIS”, 119049, Leninskiy pr. 4, Moscow (Russian Federation); Kopylov, A.N.; Anisimova, N.Yu.; Kiselevsky, M.V. [N.N. Blokhin Russian Cancer Research Center, 115478, Kashirskoye sh. 23, Moscow (Russian Federation); Maksimkin, A.V. [National University of Science and Technology “MISIS”, 119049, Leninskiy pr. 4, Moscow (Russian Federation)

    2015-03-01

    In the present work dispersion-strengthened nanocomposites based on ultra-high molecular weight polyethylene (UHMWPE) after mechanical activation were studied. Mechanical activation was performed for hardening of the boundaries between the polymer particles, reducing the fusion defects and increasing of wear-resistance. Three types of samples were prepared: UHMWPE, UHMWPE/Al{sub 2}O{sub 3} nanocomposite and UHMWPE/Al{sub 2}O{sub 3} nanocomposite after mechanical activation. UHMWPE/Al{sub 2}O{sub 3} nanocomposites prepared with mechanical activation show the best mechanical properties in compression and higher wear-resistance. UHMWPE/Al{sub 2}O{sub 3} nanocomposites prepared with mechanical activation were chosen for in vivo study by orthotopical transplantation in rats. Animals' activity has been being monitored for 60 days after surgery. No signs of inflammation, cellular infiltration, destruction of material or bone–cartilage defect were found. Implanted sample has not changed its position of implantation, there were no any shifts. Obtained data shows that UHMWPE-based nanocomposite is a promising material for creating bioimplants for cartilage defect replacement. - Highlights: • Mechanical activation of UHMWPE composite leads to changing of fracture mechanism. • Mechanical activation leads to increasing of wear-resistance of UHMWPE composite. • The presence of Al{sub 2}O{sub 3} in grain boundaries of UHMWPE inhibits crack growth. • Complete integration of UHMWPE-based implant in cartilage defect of rat was shown. • UHMWPE/Al{sub 2}O{sub 3} nanocomposite may be recommended for use in cartilage replacement.

  4. Insects feeding on cadavers as an alternative source of human genetic material

    Directory of Open Access Journals (Sweden)

    Rafał Skowronek

    2015-03-01

    Full Text Available In some criminal cases, the use of classical sources of human genetic material is difficult or even impossible. One solution may be the use of insects, especially blowfly larvae which feed on corpses. A recent review of case reports and experimental studies available in biomedical databases has shown that insects can be a valuable source of human mitochondrial and genomic deoxyribonucleic acid (DNA, allowing for an effective analysis of hypervariable region (HVR sequences and short tandem repeat (STR profiles, respectively. The optimal source of human DNA is the crop (a part of the gut of active third-instar blowfly larvae. Pupae and insect faeces can be also used in forensic genetic practice instead of the contents of the alimentary tract.

  5. The Market Gate of Miletus: damages, material characteristics and the development of a compatible mortar for restoration

    Science.gov (United States)

    Siegesmund, Siegfried; Middendorf, Bernhard

    2008-12-01

    The indoor exhibit of the Market Gate of Miletus is unique for an archaeological monument. The reconstruction of the gate was done in such a way that most marble fragments were removed leaving cored marble columns 3-4 cm in thickness. These cored columns were mounted on a steel construction and filled with different mortars or filled with specially shaped blocks of brick combined with mortar. All the missing marble elements were replaced by copies made of a Portland cement based concrete, which is compositionally similar to the original building materials. During the Second World War the monument was heavily damaged by aerial bombardment. For 2 years the Market Gate of Miletus was exposed to weathering, because a brick wall protecting the gate was also destroyed. The deterioration phenomena observed are microcracks, macroscopic fractures, flaking, sugaring, greying, salt efflorescence, calcitic-sinter layers and iron oxide formation etc. The rapid deterioration seems to be due to indoor atmospheric effects, and also by a combination of incompatible materials (e.g. marble, steel, mortar, concrete, bricks etc.). Compatible building materials like mortars or stone replacing materials have to be developed for the planned restoration. The requirements for restoration mortars are chemical-mineralogical and physical-mechanical compatibilities with the existing building materials. In detail this means that the mortar should ensure good bonding properties, adapted strength development and not stain the marble when in direct contact. The favoured mortar was developed with a hydraulic binder based on iron-free white cement and pozzolana based on activated clay. A special limestone and quartz sand mixture was used as an aggregate. The cement was adjusted using chemical additives. Specially designed tests were applied extensively to prove whether the developed mortar is suitable for the restoration of this precious monument.

  6. Deuterium ion irradiation damage and deuterium trapping mechanism in candidate stainless steel material (JPCA2) for fusion reactor

    International Nuclear Information System (INIS)

    Ashizuka, Norihiro; Kurita, Takaaki; Yoshida, Naoaki; Fujiwara, Tadashi; Muroga, Takeo

    1987-01-01

    An improved austenitic stainless steel (JPCA), a candidate material for fusion reactor, is irradiated at room temperature with deuterium ion beams. Desorption spectra of deuterium gas is measured at various increased temperatures and defects formed under irradiation are observed by transmission electron microscopy to determine the mechanism of the thermal release of deuteriums and the characteristics of irradiation-induced defects involved in the process. In the deuterium deportion spectra observed, five release stages are found to exist at 90 deg C, 160 deg C, 220 deg C, 300 deg C and 400 deg C, referred to as Stage I, II, III, IV and V, respectively. Stage I is interpreted as representing the release of deuteriums trapped in point defects (presumably vacancies) formed under irradiation. The energy of desorption from the trapping sites is estimated at 0.8 eV. Stage II is concluded to be associated with the release of deuteriums trapped in a certain kind of existing defects. Stage III involves the release of deuteriums that are trapped in dislocations, dislocation loops or dislocated portions of stacking fault tetrahedra. This release occurs significantly in processed materials and other materials irradiated with high energy ion beams that may cause cascade damage. Stage IV is interpreted in terms of thermal decomposition of small deuterium clusters. Stage V is associated with the decomposition of rather large deuterium clusters grown on the {111} plane. (Nogami, K.)

  7. A preliminary study on radiation damage effect in ceramics composite materials as innovative basic research using the HTTR

    International Nuclear Information System (INIS)

    Ishihara, Masahiro; Baba, Shinichi; Aihara, Jun; Arai, T.; Hayashi, K.; Ishino, S.

    1999-01-01

    An innovative basic research concerning with the basic science and applied technology is planned using the High Temperature Engineering Test Reactor (HTTR), which provides the advantage of not only a high temperature irradiation field above 400degC but also a large irradiation space. The first irradiation experiment is to be performed in 2001. Many research themes with a wide variety of scientific and technological interests are proposed as the innovative basic research. For the purpose of demonstration of scientific feasibility and advantages in the HTTR irradiation, several research themes have been being conducted as the preliminary studies. In this paper the outline of the innovative basic research is described, and the preliminary study on the radiation damage mechanism of ceramic composite materials is presented. (author)

  8. Scoping of material damage with FISPACT-II and different nuclear data libraries: transmutation, activation, and PKAs

    International Nuclear Information System (INIS)

    Gilbert, M.R.; Sublet, J.-Ch.

    2016-01-01

    The uncertainty associated with nuclear data, and the simulated predictions of transmutation, activation, and primary damage events derived from them, is not only that derived based on the quantified errors in a particular nuclear library. Uncertainty also manifests in comparisons between different libraries – if they do not produce the same results, then, since it often impossible to know a priori which library is best, predicted results must be considered to have an uncertainty (at least) as much as the variation between libraries. Of course, this situation is further complicated by the fact that it is not always possible, or practical, to produce results with multi-libraries. There is thus a need, within the nuclear data community, to assess different libraries, and make recommendations about the best choice of library for particular applications, in this case material science

  9. Research on Service Life of Flame Resistant Materials in the Exhibition Hall by the Use of Mechanical Method of the Meso Damage Mechanics

    OpenAIRE

    Zhang Junzhu

    2015-01-01

    The population in the exhibition hall is relatively dense, and fire incidents often occur, so the existence of flame resistant materials is very important. The flame resistant materials are used to analyze the museums, art galleries, science and technology museums and other exhibition halls. Taking two kinds of flame resistant materials, namely, Mg(OH)2 and Al(OH)3 as an example, this paper establishes a model of meso damage mechanics by the use of mechanical method of the meso damage mechani...

  10. Genetic relationship of organic bases of the quinoline and isoquinoline series from lignite semicoking tars with the initial biological material

    Energy Technology Data Exchange (ETDEWEB)

    Platonov, V.V.; Proskuryakov, V.A.; Podshibyakin, S.I.; Domogatskii, V.V.; Shvykin, A.Y.; Shavyrina, O.A.; Chilachava, K.B. [Leo Tolstoy State Pedagog University, Tula (Russian Federation)

    2002-07-01

    The genetic relationship of quinoline and isoquinoline compounds present in semicoking tars of Kimovsk lignites (near-Moscow fields) with the initial vegetable material is discussed. Transformation pathways of the native compounds in the course of lignite formation are suggested.

  11. X-ray optics research for free electron lasers: study of material damage under extreme fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Kuba, Jaroslav E-mail: kuba@llnl.gov; Wootton, Alan; Bionta, R.M.; Shepherd, Ronnie; Fill, E.E.; Ditmire, Todd; Dyer, Gilliss; London, R.A.; Shlyaptsev, V.N.; Dunn, James; Booth, Rex; Bajt, Sasa; Smith, R.F.; Feit, M.D.; Levesque, Rick; McKernan, Mark

    2003-07-11

    Free electron lasers operating in the 0.1-1.5 nm wavelength range have been proposed for the Stanford Linear Accelerator Center (USA) and DESY (Germany). The unprecedented brightness and associated fluence (up to 30 J cm{sup -2}) predicted for pulses <300 fs pose new challenges for optical components. A criterion for optical component design is required, implying an understanding of X-ray--material interactions at these extreme conditions. In our experimental effort, the extreme conditions are simulated by the currently available sources ranging from optical lasers, through X-ray lasers (XRLs) at 14.7 nm down to K-alpha sources ({approx}0.15 nm). In this paper, we present an overview of our research project on X-ray--matter interaction, including both computer modeling and preliminary results from optical laser experiments, the COMET tabletop high brightness ps XRL and a K-alpha experimental campaign carried out at the JanUSP laser facility at the Lawrence Livermore National Laboratory.

  12. X-ray optics research for free electron lasers: study of material damage under extreme fluxes

    International Nuclear Information System (INIS)

    Kuba, Jaroslav; Wootton, Alan; Bionta, R.M.; Shepherd, Ronnie; Fill, E.E.; Ditmire, Todd; Dyer, Gilliss; London, R.A.; Shlyaptsev, V.N.; Dunn, James; Booth, Rex; Bajt, Sasa; Smith, R.F.; Feit, M.D.; Levesque, Rick; McKernan, Mark

    2003-01-01

    Free electron lasers operating in the 0.1-1.5 nm wavelength range have been proposed for the Stanford Linear Accelerator Center (USA) and DESY (Germany). The unprecedented brightness and associated fluence (up to 30 J cm -2 ) predicted for pulses <300 fs pose new challenges for optical components. A criterion for optical component design is required, implying an understanding of X-ray--material interactions at these extreme conditions. In our experimental effort, the extreme conditions are simulated by the currently available sources ranging from optical lasers, through X-ray lasers (XRLs) at 14.7 nm down to K-alpha sources (∼0.15 nm). In this paper, we present an overview of our research project on X-ray--matter interaction, including both computer modeling and preliminary results from optical laser experiments, the COMET tabletop high brightness ps XRL and a K-alpha experimental campaign carried out at the JanUSP laser facility at the Lawrence Livermore National Laboratory

  13. Gene expression profiles and genetic damage in benzo(a)pyrene diol epoxide-exposed TK6 cells

    Energy Technology Data Exchange (ETDEWEB)

    Akerman, G.S.; Rosenzweig, B.A.; Domon, O.E.; McGarrity, L.J.; Blankenship, L.R.; Tsai, C.A.; Culp, S.J.; MacGregor, J.T.; Sistare, F.D.; Chen, J.J.; Morris, S.M

    2004-05-18

    Microarray analysis is a powerful tool to identify the biological effects of drugs or chemicals on cellular gene expression. In this study, we compare the relationships between traditional measures of genetic toxicology and mutagen-induced alterations in gene expression profiles. TK6 cells were incubated with 0.01, 0.1, or 1.0 {mu}M {+-}anti-benzo(a)pyrene-trans-7,8-dihydrodiol-9,10-epoxide (BPDE) for 4 h and then cultured for an additional 20 h. Aliquots of the exposed cells were removed at 4 and 24 h in order to quantify DNA adduct levels by {sup 32}P post-labeling and measure cell viability by cloning efficiency and flow cytometry. Gene expression profiles were developed by extracting total RNA from the control and exposed cells at 4 and 24 h, labeling with Cy3 or Cy5 and hybridizing to a human 350 gene array. Mutant frequencies in the Thymidine Kinase and Hypoxanthine Phosphoribosyl Transferase genes were also determined. The 10{alpha}-(deoxyguanosin-N{sup 2}-yl)-7{alpha},8{beta},9{beta}-trihydroxy-7,8,9,10-= tetrahydrobenzo(a) pyrene (dG-N{sup 2}-BPDE) adduct increased as a function of dose and was the only adduct identified. A dose-related decrease in cell viability was evident at 24 h, but not at 4 h. Cell death occurred by apoptosis. At 4 h, analysis of the gene expression profiles revealed that Glutathione Peroxidase and Gadd45 were consistently upregulated (greater than 1.5-fold and significantly (P<0.001) greater than the control in two experiments) in response to 1.0 {mu}M BPDE exposure. Fifteen genes were consistently down-regulated (less than 0.67-fold and significantly (P<0.001) lower than the control in two experiments) at 4 h in cultures exposed to 1.0 {mu}M BPDE. Genes with altered expression at 4 h included genes important in the progression of the cell-cycle and those that inhibit apoptosis. At 24 h post-exposure, 16 genes, involved in cell-cycle control, detoxification, and apoptosis were consistently upregulated; 10 genes were repressed in

  14. Material Surface Damage under High Pulse Loads Typical for ELM Bursts and Disruptions in ITER

    Science.gov (United States)

    Landman, I. S.; Pestchanyi, S. E.; Safronov, V. M.; Bazylev, B. N.; Garkusha, I. E.

    The divertor armour material for the tokamak ITER will probably be carbon manufactured as fibre composites (CFC) and tungsten as either brush-like structures or thin plates. Disruptive pulse loads where the heat deposition Q may reach 102 MJ/m 2 on a time scale Ïä of 3 ms, or operation in the ELMy H-mode at repetitive loads with Q âe 1/4 3 MJ/m2 and Ïä âe 1/4 0.3 ms, deteriorate armour performance. This work surveys recent numerical and experimental investigations of erosion mechanisms at these off-normal regimes carried out at FZK, TRINITI, and IPP-Kharkov. The modelling uses the anisotropic thermomechanics code PEGASUS-3D for the simulation of CFC brittle destruction, the surface melt motion code MEMOS-1.5D for tungsten targets, and the radiation-magnetohydrodynamics code FOREV-2D for calculating the plasma impact and simulating the heat loads for the ITER regime. Experiments aimed at validating these codes are being carried out at the plasma gun facilities MK-200UG, QSPA-T, and QSPA-Kh50 which produce powerful streams of hydrogen plasma with Q = 10–30 MJ/m2 and Ïä = 0.03–0.5 ms. Essential results are, for CFC targets, the experiments at high heat loads and the development of a local overheating model incorporated in PEGASUS-3D, and for the tungsten targets the analysis of evaporation- and melt motion erosion on the base of MEMOS-1.5D calculations for repetitive ELMs.

  15. Damage characteristics and constitutive modeling of the 2D C/SiC composite: Part II – Material model and numerical implementation

    Directory of Open Access Journals (Sweden)

    Jun Li

    2015-02-01

    Full Text Available In this work, a macroscopic non-linear constitutive model accounting for damage, inelastic strain and unilateral behavior is proposed for the 2D plain-woven C/SiC composite. A set of scalar damage variables and a new thermodynamic potential expression are introduced in the framework of continuum damage mechanics. In the deduced constitutive equations, the material’s progressive damage deactivation behavior during the compression loading is described by a continuous function, and different deactivation rates under uniaxial and biaxial compression loadings are also considered. In damage evolution laws, the coupling effect among the damage modes and impediment effect of compression stress on the development of shear damage in different plane stress states are taken into account. Besides, the general plasticity theory is applied to describing the evolution of inelastic strain in tension and/or shear stress state. The Tsai–Wu failure criterion is adopted for strength analysis. Additionally, the material model is implemented as a user-defined material subroutine (UMAT and linked to the ABAQUS finite element software, and its performance is demonstrated through several numerical examples.

  16. Taking into account of the aging and the damage in the size determination of composite materials structures

    International Nuclear Information System (INIS)

    Mercier, J.

    2006-11-01

    The aim of this study was to better understand the aging of glass fibres-epoxy composites exposed to humid conditions and loading so as to predict its effects on the lifetimes of composite structures. Water diffusion was first experimentally investigated by gravimetric method to determine water sorption kinetics for different humid conditions. A Fickian model of diffusion could describe the results obtained. Specimens, saturated at different levels, were mechanically characterised. Decreases of mechanical properties as a function of water uptake were revealed by tensile tests. Damage by cracking and the coupling with humidity were then studied. Differences between reversible and irreversible changes in properties were revealed and analysed in detail. A predictive model taking into account effects due to water and/or mechanical loading is proposed, using finite element method. As a first step, in modelling the diffusion process, the non-uniform water distribution across the composite are determined for any conditions (temperature, humidity, aging time). The resulting mechanical properties of the material, as a function of the absorbed water concentration, are determined in each point. Then, diffusion/mechanic coupled calculation allows to determine material global properties from properties at each point. It is then possible to predict continuous evolution of rigidity during aging time, at all stages of water absorption and matrix cracking, for any condition (temperature, humidity, thickness, mechanical loading level). (author)

  17. Ancient DNA in historical parchments - identifying a procedure for extraction and amplification of genetic material.

    Science.gov (United States)

    Lech, T

    2016-05-06

    Historical parchments in the form of documents, manuscripts, books, or letters, make up a large portion of cultural heritage collections. Their priceless historical value is associated with not only their content, but also the information hidden in the DNA deposited on them. Analyses of ancient DNA (aDNA) retrieved from parchments can be used in various investigations, including, but not limited to, studying their authentication, tracing the development of the culture, diplomacy, and technology, as well as obtaining information on the usage and domestication of animals. This article proposes and verifies a procedure for aDNA recovery from historical parchments and its appropriate preparation for further analyses. This study involved experimental selection of an aDNA extraction method with the highest efficiency and quality of extracted genetic material, from among the multi-stage phenol-chloroform extraction methods, and the modern, column-based techniques that use selective DNA-binding membranes. Moreover, current techniques to amplify entire genetic material were questioned, and the possibility of using mitochondrial DNA for species identification was analyzed. The usefulness of the proposed procedure was successfully confirmed in identification tests of historical parchments dating back to the 13-16th century AD.

  18. Action of the chlorophyllin on the genetic damage induced by gamma radiation in germinal cells of Drosophila Melanogaster

    International Nuclear Information System (INIS)

    Cruces, M.P.; Pimentel, A.E.; Moreno, A.; Moreno, R.

    2003-01-01

    The obtained results using somatic cells, they have evidenced that the chlorophyllin (CHLN) it can act inhibiting or increasing the damage caused by different mutagens. The objective of this investigation is to evaluate the effect of the CHLN on the damage induced by gamma radiation in germinal cells of Drosophila. Two tests were used, the lost of the X chromosome and the conventional test of lethal recessive bound to the sex (LRLS); both with a system of litters. The obtained results in both essays, indicated that the CHLN doesn't reduce the damage induced by the gamma radiation in none of the cellular monitored states. (Author)

  19. Genetic damage induced by trophic doses of lead in the neotropical fish Hoplias malabaricus (Characiformes, Erythrinidae as revealed by the comet assay and chromosomal aberrations

    Directory of Open Access Journals (Sweden)

    Marta Margarete Cestari

    2004-01-01

    Full Text Available The effects of clastogenic or mutagenic agents have rarely been studied in neotropical fish species exposed to contaminated water. In this study, the genetic damage caused by lead in the widely distributed South American fish, Hoplias malabaricus, was assessed using the comet (SCGE assay and by testing for chromosomal aberrations. Eighteen specimens were acclimatized to laboratory conditions and then chronically exposed to contaminated food by feeding prey (Cyprinus sp. injected intraperitoneally with doses of inorganic lead adjusted to give a contamination level of 21 mg of Pb2+.g-1 net weight of H. malabaricus. Three fish were sampled for chromosomal analysis after four doses (18 days and another three after eight doses (41 days of lead and the results then compared with three untreated controls kept under lead-free conditions. An additional six treated fish and three controls were sampled for the comet assay after 13 doses (64 days. Exposure to lead significantly increased the frequency of chromosomal aberrations and the frequency of tailed cell nuclei, the latter indicating DNA damage. These results show that H. malabaricus is a useful biological model for screening the clastogenic effects of lead and possibly other xenobiotics. The genetic damage seen here illustrates the need to investigate the potential effects of heavy metals on fish species in South America.

  20. Single cell gel electrophoresis as a tool to assess genetic damage in Heleobia cf. australis (Mollusca: Gastropoda as sentinel for industrial and domestic pollution in Montevideo bay (Uruguay

    Directory of Open Access Journals (Sweden)

    Silvia Villar

    2015-09-01

    Full Text Available AbstractThe knowledge of the extent of DNA damage in aquatic organisms in polluted areas is an important issue because contamination may alter their health at sublethal levels. Although molluscs have been widely used to monitor water pollution, there are no records of in vivo genotoxicity studies. Heleobia cf. australis, is distributed in almost all Uruguayan coastal ecosystems, including highly polluted sites. The comet assay is a damage genetic biomarker based on the migration of negatively charged DNA fragments produced by mutagenic agents in individual cells. Live individuals were collected in the Montevideo Bay (impacted area and Laguna Garzón (control to analyze the presence of mutagenic agents in the former site through comet assay. Cells from organisms of the impacted area showed significantly higher levels of genetic damage than those obtained in the control population, measured by percentage of DNA in the tail. Although preliminary, this approach supports the idea that H. cf. australis could be used as a sentinel to evaluate the presence of mutagenic agents in estuarine environments, alerting to the impact of contamination in its early stages.

  1. Genetic polymorphisms and possible gene-gene interactions in metabolic and DNA repair genes: Effects on DNA damage

    Czech Academy of Sciences Publication Activity Database

    Naccarati, Alessio; Souček, P.; Štětina, R.; Haufroid, V.; Kumar, R.; Vodičková, Ludmila; Trtková, K.; Dušinská, M.; Hemminki, K.; Vodička, Pavel

    2006-01-01

    Roč. 593, 1-2 (2006), s. 22-31 ISSN 0027-5107 R&D Projects: GA ČR GA310/03/0437 Institutional research plan: CEZ:AV0Z5039906 Keywords : Single-strand breaks * Genetic polymorphisms * Metabolism Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.111, year: 2006

  2. Evaluation by instrumented indentation of the damage caused by gamma radiation on polymeric materials; Avaliacao por indentacao instrumentada dos danos causados pela radiacao gama em materiais polimericos

    Energy Technology Data Exchange (ETDEWEB)

    Rosa, M.P.; Azevedo, E.C.; Miquelin, C.A.; Soboll, D.S., E-mail: helunica@yahoo.com.b [Universidade Tecnologica Federal do Parana (DAFIS/UTFPR), Curitiba, PR (Brazil). Dept. Academico de Fisica

    2010-07-01

    Several materials with densities close to water are used as phantoms in dosimetry. Such materials are damaged because they are exposed to radiation, the surface layers suffer the largest changes. This damage can be assessed by instrumented indentation. This paper investigates the variations in hardness and elastic modulus of samples of polymethyl-methacrylate, polyvinyl chloride, polyacetal and polypropylene before and after being irradiated with gamma radiation dose 500 Gy, using a Nanoindeter XP, with applied loads between 1 mN and 400 mN. The results are discussed correlating the variations in the mechanical properties of polymers with their applications. (author)

  3. Long-term strength curves generated by the nonlinear Maxwell-type model for viscoelastoplastic materials and the linear damage rule under step loading

    Directory of Open Access Journals (Sweden)

    Andrew V. Khokhlov

    2016-09-01

    Full Text Available The nonlinear Maxwell-type constitutive relation with two arbitrary material functions is formulated for viscoelastoplastic materials and studied analytically in uni-axial case to reveal capabilities of the model and its applicability scope. Its coupling with a number of fracture criteria is analyzed in order to simulate creep rupture under constant and piecewise-constant loading and to compare creep life estimates arising as a result. The limit strain criterion, the critical dissipation criterion and two proposed new families of failure criteria taking into account a strain history (i.e. a whole creep curve are considered. Long-term strength curves equations generated by each one of the four chosen failure criteria are derived. Their general qualitative properties are analyzed and compared to each other under minimal restrictions on material functions of the constitutive relation. It is proved that qualitative properties of all theoretic long-term strength curves coincide with basic properties of typical test long-term strength curves of viscoelastoplastic materials. For every failure criteria considered herein, rapture time under step-wise loading is evaluated for arbitrary material functions and compared to the lifetime yielding from the linear damage accumulation rule (i.e. “Miner’s rule”. General formulas for cumulative damage (“Miner’s sum” deviations from unity are obtained for all failure criteria coupled with the nonlinear Maxwell-type constitutive relation. Their dependences on material functions and loading program parameters are examined. In particular, it is proved that the linear damage rule is exactly valid for the critical dissipation criterion whatever material functions, number of loading steps and stress levels are chosen. On the contrary, for the limit strain criterion, the linear damage rule is never valid for two-step loading and cumulative damage at rapture instant is greater or less than unity depending on the

  4. Effects of wearing bio-active material coated fabric against γ-irradiation-induced cellular damaged in Sprague-Dawley rats

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Jung Ae; Kim, Hye Rim; Yoon, Sun Hye; Nam, Sang Hyun; Park, Sang Hyun; Jang, Beom Su [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Go, Kyung Chan; Yang, Gwang Wung; Rho, Young Hwan; Park, Hyo Suk [Research and Development Center, VENTEX Co. Ltd., Seoul (Korea, Republic of)

    2016-09-15

    Ionizing radiation causes cellular damage and death through the direct damage and/or indirectly the production of ROS, which induces oxidative stress. This study was designed to evaluate the in vivo radioprotective effects of a bio-active material coated fabric (BMCF) against γ-irradiation-induced cellular damage in Sprague-Dawley (SD) rats. Healthy male SD rats wore bio-active material coated (concentrations in 10% and 30%) fabric for 7 days after 3 Gy of γ-irradiation. Radioprotective effects were evaluated by performing various biochemical assays including spleen and thymus index, WBC count, hepatic damage marker enzymes [aspartate transaminase (AST) and alanine transaminase (ALT)] in plasma, liver antioxidant enzymes, and mitochondrial activity in muscle. Exposure to γ-irradiation resulted in hepatocellular and immune systemic damage. Gamma-irradiation induced decreases in antioxidant enzymes. However, wearing the BMCF-30% decreased significantly AST and ALT activities in plasma. Furthermore, wearing the BMCF-30% increased SOD (superoxide dismutase) and mitochondrial activity. These results suggest that wearing BMCF offers effective radioprotection against γ-irradiation-induced cellular damage in SD rats.

  5. Neutron radiation damage studies in the structural materials of a 500 MWe fast breeder reactor using DPA cross-sections from ENDF / B-VII.1

    Science.gov (United States)

    Saha, Uttiyoarnab; Devan, K.; Bachchan, Abhitab; Pandikumar, G.; Ganesan, S.

    2018-04-01

    The radiation damage in the structural materials of a 500 MWe Indian prototype fast breeder reactor (PFBR) is re-assessed by computing the neutron displacement per atom (dpa) cross-sections from the recent nuclear data library evaluated by the USA, ENDF / B-VII.1, wherein revisions were taken place in the new evaluations of basic nuclear data because of using the state-of-the-art neutron cross-section experiments, nuclear model-based predictions and modern data evaluation techniques. An indigenous computer code, computation of radiation damage (CRaD), is developed at our centre to compute primary-knock-on atom (PKA) spectra and displacement cross-sections of materials both in point-wise and any chosen group structure from the evaluated nuclear data libraries. The new radiation damage model, athermal recombination-corrected displacement per atom (arc-dpa), developed based on molecular dynamics simulations is also incorporated in our study. This work is the result of our earlier initiatives to overcome some of the limitations experienced while using codes like RECOIL, SPECTER and NJOY 2016, to estimate radiation damage. Agreement of CRaD results with other codes and ASTM standard for Fe dpa cross-section is found good. The present estimate of total dpa in D-9 steel of PFBR necessitates renormalisation of experimental correlations of dpa and radiation damage to ensure consistency of damage prediction with ENDF / B-VII.1 library.

  6. 3D/4D analyses of damage and fracture behaviours in structural materials via synchrotron X-ray tomography.

    Science.gov (United States)

    Toda, Hiroyuki

    2014-11-01

    X-ray microtomography has been utilized for the in-situ observation of various structural metals under external loading. Recent advances in X-ray microtomography provide remarkable tools to image the interior of materials. In-situ X-ray microtomography provides a unique possibility to access the 3D character of internal microstructure and its time evolution behaviours non-destructively, thereby enabling advanced techniques for measuring local strain distribution. Local strain mapping is readily enabled by processing such high-resolution tomographic images either by the particle tracking technique or the digital image correlation technique [1]. Procedures for tracking microstructural features which have been developed by the authors [2], have been applied to analyse localised deformation and damage evolution in a material [3]. Typically several tens of thousands of microstructural features, such as particles and pores, are tracked in a tomographic specimen (0.2 - 0.3 mm(3) in volume). When a sufficient number of microstructural features is dispersed in 3D space, the Delaunay tessellation algorithm is used to obtain local strain distribution. With these techniques, 3D strain fields can be measured with reasonable accuracy. Even local crack driving forces, such as local variations in the stress intensity factor, crack tip opening displacement and J integral along a crack front line, can be measured from discrete crack tip displacement fields [4]. In the present presentation, complicated crack initiation and growth behaviour and the extensive formation of micro cracks ahead of a crack tip are introduced as examples.A novel experimental method has recently been developed by amalgamating a pencil beam X-Ray diffraction (XRD) technique with the microstructural tracking technique [5]. The technique provides information about individual grain orientations and 1-micron-level grain morphologies in 3D together with high-density local strain mapping. The application of this

  7. Modeling of the fatigue damage accumulation processes in the material of NPP design units under thermomechanical unstationary effects. Estimation of spent life and forecast of residual life

    International Nuclear Information System (INIS)

    Kiriushin, A.I.; Korotkikh, Yu.G.; Gorodov, G.F.

    2002-01-01

    Full text: The estimation problems of spent life and forecast of residual life of NPP equipment design units, operated at unstationary thermal force loads are considered. These loads are, as a rule, unregular and cause rotation of main stress tensor platforms of the most loaded zones of structural elements and viscoelastic plastic deformation of material in the places of stresses concentrations. The existing engineering approaches to the damages accumulation processes calculation in the material of structural units, their advantages and disadvantages are analyzed. For the processes of fatigue damages accumulation a model is proposed, which allows to take into account the unregular pattern of deformation multiaxiality of stressed state, rotation of main platforms, non-linear summation of damages at the loading mode change. The model in based on the equations of damaged medium mechanics, including the equations of viscoplastic deformation of the material and evolutionary equations of damages accumulation. The algorithms of spent life estimation and residual life forecast of the controlled equipment and systems zones are made on the bases of the given model by the known real history of loading, which is determined by real model of NPP operation. The results of numerical experiments on the basis of given model for various processes of thermal force loads and their comparison with experimental results are presented. (author)

  8. Oxidative damage to biological macromolecules in Prague bus drivers and garagemen: impact of air pollution and genetic polymorphisms.

    Science.gov (United States)

    Bagryantseva, Yana; Novotna, Bozena; Rossner, Pavel; Chvatalova, Irena; Milcova, Alena; Svecova, Vlasta; Lnenickova, Zdena; Solansky, Ivo; Sram, Radim J

    2010-11-10

    DNA integrity was investigated in the lymphocytes of 50 bus drivers, 20 garagemen and 50 controls using the comet assay with excision repair enzymes. In parallel, 8-oxo-7,8-dihydro-2'-deoxyguanosine and 15-F(2t)-isoprostane levels in the urine and protein carbonyl levels in the plasma were assessed as markers of oxidative damage to DNA, lipids and proteins. Exposure to carcinogenic polycyclic aromatic hydrocarbons (cPAHs) and volatile compounds was measured by personal samplers for 48 and 24h, respectively, before the collection of biological specimens. Both exposed groups exhibited a higher levels of DNA instability and oxidative damage to biological macromolecules than the controls. The incidence of oxidized lesions in lymphocyte DNA, but not the urinary levels of 8-oxodG, correlated with exposure to benzene and triglycerides increased this damage. Oxidative damage to lipids and proteins was associated with exposure to cPAHs and the lipid peroxidation levels positively correlated with age and LDL cholesterol, and negatively with vitamin C. The carriers of at least one variant hOGG1 (Cys) allele tended to higher oxidative damage to lymphocyte DNA than those with the wild genotype, while XPD23 (Gln/Gln) homozygotes were more susceptible to the induction of DNA strand breaks. In contrast, GSTM1 null variant seemed to protect DNA integrity. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  9. Characterization of mechanical damage mechanisms in ceramic composite materials. Technical report, 23 May 1987-24 May 1988

    Energy Technology Data Exchange (ETDEWEB)

    Lankford, J.

    1988-09-01

    High-strain-rate compressive failure mechanisms in fiber-reinforced ceramic-matrix composite materials were characterized. These are contrasted with composite damage development at low-strain rates, and with the dynamic failure of monolithic ceramics. It is shown that it is possible to derive major strain-rate strengthening benefits if a major fraction of the fiber reinforcement is aligned with the load axis. This effect considerably exceeds the inertial microfracture strengthening observed in monolithic ceramics, and non-aligned composites. Its basis is shown to be the trans-specimen propagation time period for heterogeneously-nucleated, high-strain kink bands. A brief study on zirconia focused on the remarkable inverse strength-strain rate result previously observed for both fully and partially-stabilized zirconia single crystals, whereby the strength decreased with increasing strain rate. Based on the hypothesis that the suppression of microplastic flow, hence, local stress relaxation, might be responsible for this behavior, fully stabilized (i.e., non-transformable) specimens were strain-gaged and subjected to compressive microstrain. The rather stunning observation was that the crystals are highly microplastic, exhibiting plastic yield on loading and anelasticity and reverse plasticity upon unloading. These results clearly support the hypothesis that with increasing strain rate, microcracking is favored at the expense of microplasticity.

  10. Detecting un-authorized genetically modified organisms (GMOs) and derived materials.

    Science.gov (United States)

    Holst-Jensen, Arne; Bertheau, Yves; de Loose, Marc; Grohmann, Lutz; Hamels, Sandrine; Hougs, Lotte; Morisset, Dany; Pecoraro, Sven; Pla, Maria; Van den Bulcke, Marc; Wulff, Doerte

    2012-01-01

    Genetically modified plants, in the following referred to as genetically modified organisms or GMOs, have been commercially grown for almost two decades. In 2010 approximately 10% of the total global crop acreage was planted with GMOs (James, 2011). More than 30 countries have been growing commercial GMOs, and many more have performed field trials. Although the majority of commercial GMOs both in terms of acreage and specific events belong to the four species: soybean, maize, cotton and rapeseed, there are another 20+ species where GMOs are commercialized or in the pipeline for commercialization. The number of GMOs cultivated in field trials or for commercial production has constantly increased during this time period. So have the number of species, the number of countries involved, the diversity of novel (added) genetic elements and the global trade. All of these factors contribute to the increasing complexity of detecting and correctly identifying GMO derived material. Many jurisdictions, including the European Union (EU), legally distinguish between authorized (and therefore legal) and un-authorized (and therefore illegal) GMOs. Information about the developments, field trials, authorizations, cultivation, trade and observations made in the official GMO control laboratories in different countries around the world is often limited, despite several attempts such as the OECD BioTrack for voluntary dissemination of data. This lack of information inevitably makes it challenging to detect and identify GMOs, especially the un-authorized GMOs. The present paper reviews the state of the art technologies and approaches in light of coverage, practicability, sensitivity and limitations. Emphasis is put on exemplifying practical detection of un-authorized GMOs. Although this paper has a European (EU) bias when examples are given, the contents have global relevance. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. The effect of ultrasound and its combination with radiation on the genetic material of Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Silhankova, L.; Malkova-Kadlecova, Z.; Studlarova, Z.

    1978-01-01

    Ultrasonic radiation at 20 kHz with intensity 35 W/cm 2 and amplitude 15 to 25 μm applied to a diploid strain of Saccharomyces cerevisiae was found to act as a weak mutagen with maximum efficiency at the 20% survival of the cells. Under these conditions, the frequency of reversion of the suppressible allele ilv1-92 increased ten times, the frequency of mitotic gene conversion four times. Doses leading to survivals lower than 20% led to a slight increase in the frequency of cytoplasmic respiration-deficient mutants. Submutagenic doses applied immediately after γ or UV irradiation did not substantially increase the effect of these physical agents on the genetic material of the yeast strain investigated. Application of ultrasound prior to UV radiation did not considerably influence the effect of the UV radiation either. (author)

  12. Small molecule inhibitors uncover synthetic genetic interactions of human flap endonuclease 1 (FEN1 with DNA damage response genes.

    Directory of Open Access Journals (Sweden)

    Thomas A Ward

    Full Text Available Flap endonuclease 1 (FEN1 is a structure selective endonuclease required for proficient DNA replication and the repair of DNA damage. Cellularly active inhibitors of this enzyme have previously been shown to induce a DNA damage response and, ultimately, cell death. High-throughput screens of human cancer cell-lines identify colorectal and gastric cell-lines with microsatellite instability (MSI as enriched for cellular sensitivity to N-hydroxyurea series inhibitors of FEN1, but not the PARP inhibitor olaparib or other inhibitors of the DNA damage response. This sensitivity is due to a synthetic lethal interaction between FEN1 and MRE11A, which is often mutated in MSI cancers through instabilities at a poly(T microsatellite repeat. Disruption of ATM is similarly synthetic lethal with FEN1 inhibition, suggesting that disruption of FEN1 function leads to the accumulation of DNA double-strand breaks. These are likely a result of the accumulation of aberrant replication forks, that accumulate as a consequence of a failure in Okazaki fragment maturation, as inhibition of FEN1 is toxic in cells disrupted for the Fanconi anemia pathway and post-replication repair. Furthermore, RAD51 foci accumulate as a consequence of FEN1 inhibition and the toxicity of FEN1 inhibitors increases in cells disrupted for the homologous recombination pathway, suggesting a role for homologous recombination in the resolution of damage induced by FEN1 inhibition. Finally, FEN1 appears to be required for the repair of damage induced by olaparib and cisplatin within the Fanconi anemia pathway, and may play a role in the repair of damage associated with its own disruption.

  13. Genetic engineered color silk: fabrication of a photonics material through a bioassisted technology.

    Science.gov (United States)

    Shimizu, Katsuhiko

    2018-04-05

    Silk produced by the silkworm Bombyx mori is an attractive material because of its luster, smooth and soft texture, conspicuous mechanical strength, good biocompatibility, slow biodegradation, and carbon neutral synthesis. Silkworms have been domesticated and bred for production of better quality and quantity of silk, resulting in the development of sericulture and the textile industry. Silk is generally white, so dyeing is required to obtain colored fiber. However, the dyeing process involves harsh conditions and generates a large volume of waste water, which have environmentally and economically negative impacts. Although some strains produce cocoons that contain pigments derived from the mulberry leaves that they eat, the pigments are distributed in the sericin layer and are lost during gumming. In trials for production of colored silk by feeding silkworms on diets containing dyes, only limited species of dye molecules were incorporated into the silk threads. A method for the generation of transgenic silkworm was established in conjunction with the discovery of green fluorescent protein (GFP), and silkworms carrying the GFP gene spun silk threads that formed cocoons that glowed bright green and still retained the original properties of silk. A wide range of color variation of silk threads has been obtained by replacing the GFP gene with the genes of other fluorescent proteins chosen from the fluorescent protein palette. The genetically modified silk with photonic properties can be processed to form various products including linear threads, two-dimensional fabrics, and three-dimensional materials. The transgenic colored silk could be economically advantageous due to addition of a new value to silk and reduction of cost for water waste, and environmentally preferable for saving water. Here, I review the literature regarding the production methods of fluorescent silk from transgenic silkworms and present examples of genetically modified color silk. © 2018 IOP

  14. Genetic effects of ionizing radiation

    International Nuclear Information System (INIS)

    Myers, D.K.; Childs, J.D.

    1980-01-01

    The genetic material in living organisms is susceptible to damage from a wide variety of causes including radiation exposure. Most of this damage is repaired by the organism; the residual damage and damage which is not correctly repaired can lead to genetic changes such as mutations. In lower organisms, most offspring carry an unaltered copy of the genetic information that was present in the parental organism, most of the genetic changes which do occur are not caused by natural background radiation, and the increase in frequency of genetic changes after irradiation at low-dose rates is directly proportional to total radiation dose. The same principles appear to be valid in mammals and other higher organisms. About 105 out of every 1000 humans born suffer from some genetic or partly-genetic condition requiring medical attention at some time. It has been estimated that approximately 1 person in every 2000 born carry a deleterious genetic mutation that was caused by the continued exposure of many generations of our ancestors to natural background radiation. On the same basis, it is predicted that the incidence of genetic diseases would be increased to 106 per 1000 in the children and grandchildren of radiation workers who were exposed to 1 rem per year commencing at age 18. However, there was no detectable change in the health and fitness of mice whose male ancestors were repeatedly exposed to high radiation doses up to 900 rem per generation. (auth)

  15. Research on Service Life of Flame Resistant Materials in the Exhibition Hall by the Use of Mechanical Method of the Meso Damage Mechanics

    Directory of Open Access Journals (Sweden)

    Zhang Junzhu

    2015-01-01

    Full Text Available The population in the exhibition hall is relatively dense, and fire incidents often occur, so the existence of flame resistant materials is very important. The flame resistant materials are used to analyze the museums, art galleries, science and technology museums and other exhibition halls. Taking two kinds of flame resistant materials, namely, Mg(OH2 and Al(OH3 as an example, this paper establishes a model of meso damage mechanics by the use of mechanical method of the meso damage mechanics, and researches the macro mechanical properties of the thermal insulation materials and decorative materials so as to predict its service life. This research finds that the use of two kinds of flame resistant materials, namely, Mg(OH2 and Al(OH3 can improve the elasticity modulus of the thermal insulation materials and decorative materials used in the construction, so that its macro mechanical properties can have a significant improvement, and its service life can also have a significant improvement after adding flame retardant materials.

  16. Ground water pollution by arsenic and its effects on health. Involvement of metabolic methylation in arsenic-induced genetic damage and tumorigenesis; Muki hiso no mechiru ka taisha to idenshi shogaisei narabini shuyo yuhatsusei

    Energy Technology Data Exchange (ETDEWEB)

    Yamanaka, K. [Nihon Univ., Tokyo (Japan)] Okada, S. [Shizuoka Prefecture (Japan)

    1997-07-10

    Drinking water contamination has become a worldwide problem. It is pointed out that re-evaluation of genetic damage with carcinogen is considered as an important problem particularly arsenic`s effects on health. To explain the genetic damage development mechanism of arsenic compound, results of the research conducted on the action of arsenic compound which develops during metabolic methylation process and inorganic arsenic are explained in this paper. The results of the study are summarized as follows. Arsenic genetic damage mutation is caused by dimethyl arsenic in main metabolism than inorganic arsenic. Lung DNA damage is induced by the interaction of O2 and arsenic peroxide radical. Dimethyl arsenic shows very important effect on lung cancer formation process which is induced based on 4-nitroquinoline-1-oxide (4NQO). It not only promotes lung cancer but it also plays an important role in malignant tumor`s mutation. 25 refs., 2 figs.

  17. Survival of extensively damaged endodontically treated incisors restored with different types of posts-and-core foundation restoration material.

    Science.gov (United States)

    Lazari, Priscilla Cardoso; de Carvalho, Marco Aurélio; Del Bel Cury, Altair A; Magne, Pascal

    2017-09-16

    analysis (log-rank post hoc test at α=.05 for pairwise comparisons). None of the tested specimen withstood all 140 000 cycles. All specimens without a ferrule were affected by an initial failure phenomenon (wide gap at the lingual margin between the core foundation restoration/crown assembly and the root). NfPfP, NfPt, and NfPtB had similar survival (29649 to 30987 mean cycles until initial failure). NfPfB outperformed NfPt and NfPtB. None of the post-and-core foundation restoration materials were able to match the performance of the ferrule group FPf (72667 cycles). In all groups, 100% of failures were catastrophic. The survival of extensively damaged endodontically treated incisors without a ferrule was slightly improved by the use of a fiber post with a bulk-fill composite resin core foundation restoration. However, none of the post-and-core techniques was able to compensate for the absence of a ferrule. The presence of the posts always adversely affected the failure mode. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  18. Development of genomic DNA reference materials for genetic testing of disorders common in people of ashkenazi jewish descent.

    Science.gov (United States)

    Kalman, Lisa; Wilson, Jean Amos; Buller, Arlene; Dixon, John; Edelmann, Lisa; Geller, Louis; Highsmith, William Edward; Holtegaard, Leonard; Kornreich, Ruth; Rohlfs, Elizabeth M; Payeur, Toby L; Sellers, Tina; Toji, Lorraine; Muralidharan, Kasinathan

    2009-11-01

    Many recessive genetic disorders are found at a higher incidence in people of Ashkenazi Jewish (AJ) descent than in the general population. The American College of Medical Genetics and the American College of Obstetricians and Gynecologists have recommended that individuals of AJ descent undergo carrier screening for Tay Sachs disease, Canavan disease, familial dysautonomia, mucolipidosis IV, Niemann-Pick disease type A, Fanconi anemia type C, Bloom syndrome, and Gaucher disease. Although these recommendations have led to increased test volumes and number of laboratories offering AJ screening, well-characterized genomic reference materials are not publicly available. The Centers for Disease Control and Prevention-based Genetic Testing Reference Materials Coordination Program, in collaboration with members of the genetic testing community and Coriell Cell Repositories, have developed a panel of characterized genomic reference materials for AJ genetic testing. DNA from 31 cell lines, representing many of the common alleles for Tay Sachs disease, Canavan disease, familial dysautonomia, mucolipidosis IV, Niemann-Pick disease type A, Fanconi anemia type C, Bloom syndrome, Gaucher disease, and glycogen storage disease, was prepared by the Repository and tested in six clinical laboratories using three different PCR-based assay platforms. A total of 33 disease alleles was assayed and 25 different alleles were identified. These characterized materials are publicly available from Coriell and may be used for quality control, proficiency testing, test development, and research.

  19. Bilingual Cancer Genetic Education Modules for the Deaf Community: Development and Evaluation of the Online Video Material.

    Science.gov (United States)

    Boudreault, Patrick; Wolfson, Alicia; Berman, Barbara; Venne, Vickie L; Sinsheimer, Janet S; Palmer, Christina

    2018-04-01

    Health information about inherited forms of cancer and the role of family history in cancer risk for the American Sign Language (ASL) Deaf community, a linguistic and cultural community, needs improvement. Cancer genetic education materials available in English print format are not accessible for many sign language users because English is not their native or primary language. Per Center for Disease Control and Prevention recommendations, the level of literacy for printed health education materials should not be higher than 6th grade level (~ 11 to 12 years old), and even with this recommendation, printed materials are still not accessible to sign language users or other nonnative English speakers. Genetic counseling is becoming an integral part of healthcare, but often ASL users are not considered when health education materials are developed. As a result, there are few genetic counseling materials available in ASL. Online tools such as video and closed captioning offer opportunities for educators and genetic counselors to provide digital access to genetic information in ASL to the Deaf community. The Deaf Genetics Project team used a bilingual approach to develop a 37-min interactive Cancer Genetics Education Module (CGEM) video in ASL with closed captions and quizzes, and demonstrated that this approach resulted in greater cancer genetic knowledge and increased intentions to obtain counseling or testing, compared to standard English text information (Palmer et al., Disability and Health Journal, 10(1):23-32, 2017). Though visually enhanced educational materials have been developed for sign language users with multimodal/lingual approach, little is known about design features that can accommodate a diverse audience of sign language users so the material is engaging to a wide audience. The main objectives of this paper are to describe the development of the CGEM and to determine if viewer demographic characteristics are associated with two measurable aspects of

  20. An Energy-Equivalent d⁺/d-Damage Model with Enhanced Microcrack Closure-Reopening Capabilities for Cohesive-Frictional Materials.

    Science.gov (United States)

    Cervera, Miguel; Tesei, Claudia

    2017-04-20

    In this paper, an energy-equivalent orthotropic d ⁺/ d - damage model for cohesive-frictional materials is formulated. Two essential mechanical features are addressed, the damage-induced anisotropy and the microcrack closure-reopening (MCR) effects, in order to provide an enhancement of the original d ⁺/ d - model proposed by Faria et al. 1998, while keeping its high algorithmic efficiency unaltered. First, in order to ensure the symmetry and positive definiteness of the secant operator, the new formulation is developed in an energy-equivalence framework. This proves thermodynamic consistency and allows one to describe a fundamental feature of the orthotropic damage models, i.e., the reduction of the Poisson's ratio throughout the damage process. Secondly, a "multidirectional" damage procedure is presented to extend the MCR capabilities of the original model. The fundamental aspects of this approach, devised for generic cyclic conditions, lie in maintaining only two scalar damage variables in the constitutive law, while preserving memory of the degradation directionality. The enhanced unilateral capabilities are explored with reference to the problem of a panel subjected to in-plane cyclic shear, with or without vertical pre-compression; depending on the ratio between shear and pre-compression, an absent, a partial or a complete stiffness recovery is simulated with the new multidirectional procedure.

  1. Diffusional mass transport phenomena in the buffer material and damaged zone of a borehole wall in an underground nuclear fuel waste vault

    International Nuclear Information System (INIS)

    Page, S.; Cheung, S.C.H.

    1983-06-01

    The effects of the geometry of the borehole and the characteristics of the damaged borehole rock wall on the movement of the radionuclides from an underground nuclear waste vault have been studied. The results show that radionuclide transport will occur mainly through the buffer into the damaged zone of the borehole wall. As the degree of facturing of the damaged zone increases, the total radionuclide flux will increase up to a limit which can be approximated by a one-dimensional radial diffusion model. For large degrees of fracturing of the damaged zone, an increase in the radial buffer material thickness will decrease the total flux, whereas, for small degrees of fracturing, an increase in the radial buffer thickness may slightly increase the total flux. Increasing the vertical buffer thickness will significantly decrease the total flux when the degree of fracturing of the damaged zone is small. An increase in the vertical extent of the damaged zone will cause an increase in total flux

  2. Progress report on research and development work 1991 of the Institute of Genetics and Toxicology of Fissionable Materials, Karlsruhe Nuclear Research Center

    International Nuclear Information System (INIS)

    1991-03-01

    The present annual report describes the results of research work done by the Institute of Genetics and Toxicology of Fissionable Materials (IGT) in 1991. The following eight subjects were dealt with: genetic repair; genetic regulation; biological carcinogenesis; molecular genetics of eukaryontic genes; genetic mouse models for human illnesses; radiation toxicology of actinides; molecular and cellular environmental toxicology, and in vivo fractionation and speciation of actinides. (MG) [de

  3. Genetics

    Science.gov (United States)

    ... Likelihood of getting certain diseases Mental abilities Natural talents An abnormal trait (anomaly) that is passed down ... one of them has a genetic disorder. Information Human beings have cells with 46 chromosomes . These consist ...

  4. Micromechanisms of damage in 0 deg. splits in a [90/0]{sub s} composite material using synchrotron radiation computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Moffat, A.J. [School of Engineering Sciences, University of Southampton, University Road, Southampton, Hants SO17 1BJ (United Kingdom)], E-mail: ajmoffat@soton.ac.uk; Wright, P. [School of Engineering Sciences, University of Southampton, University Road, Southampton, Hants SO17 1BJ (United Kingdom); Buffiere, J.-Y. [MATEIS, INSA de Lyon, Universite de Lyon (France); Sinclair, I.; Spearing, S.M. [School of Engineering Sciences, University of Southampton, University Road, Southampton, Hants SO17 1BJ (United Kingdom)

    2008-11-15

    In situ synchrotron radiation computed tomography has been used to investigate 0 deg. ply splits in a [90/0]{sub s} carbon fibre-epoxy laminate. This technique allows for direct three-dimensional observations of damage. Micromechanisms such as pinning and bridging have been observed in rubber-toughened, resin-rich regions. Crack opening and shear displacements associated with 0 deg. splits have been quantified and this work demonstrates that this technique may be particularly useful for determining full-field strain maps around damage in composite materials.

  5. The interferon gamma gene in celiac disease: augmented expression correlates with tissue damage but no evidence for genetic susceptibility.

    NARCIS (Netherlands)

    Wapenaar, M.C.; Belzen, M.J van; Fransen, J.H.; Sarasqueta, A.F.; Houwen, R.H.J.; Meijer, J.W.; Mulder, C.J.J.; Wijmenga, C.

    2004-01-01

    Celiac disease (CD) is a complex genetic disorder characterized by gluten intolerance. The Th1 immune response, with a key position for interferon gamma (IFN-gamma), is an important determinant of intestinal remodeling in CD. We aimed at further ascertaining the role of IFN-gamma, either as a

  6. Genetic polymorphisms influence the susceptibility of men to sperm DNA damage associated with exposure to air pollution

    Czech Academy of Sciences Publication Activity Database

    Rubeš, J.; Rybář, R.; Přinosilová, P.; Věžník, Z.; Chvátalová, Irena; Solanský, I.; Šrám, Radim

    2010-01-01

    Roč. 683, 1-2 (2010), s. 9-15 ISSN 0027-5107 R&D Projects: GA AV ČR 1QS500390506 Institutional research plan: CEZ:AV0Z50390512; CEZ:AV0Z50390703 Keywords : Gene-environment interaction * sperm chromatin structure assay * sperm DNA damage Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 3.204, year: 2010

  7. DNA as Genetic Material: Revisiting Classical Experiments through an Easy, Practical Class

    Directory of Open Access Journals (Sweden)

    W. J. Malagó

    2009-05-01

    Full Text Available In 1928, Frederick Griffith demonstrated a process of transmission of genetic information by transforming  Pneumococcus. In 1944, Oswald Avery, Colin Munro MacLeod and Maclyn McCarty showed that Griffith´stransformation principle  is DNA. Here, we intend to revisit these classicalexperiments by reproducing them in easier adapted forms, for a practical class given to undergraduate students. The Griffith experiment was reproduced by mixing heat-killed, ampicillin - resistant  E. coliwith live ampicillin -susceptible  E. coli, followed by plating samples in the presence or absence of the antibiotic. Cells were also plated separately as control. Avery’s work was reproduced by pre-treating a purified plasmid harboring the ampicillin resistan ce gene with Dnase I. Treated and untreated plasmids were then used to transform  E. colicells, which were plated in culture media containing ampicillin. The students received a class guide with brief theoretical explanations and protocols to perform the experiments. The original papers by Griffith and Avery  et al. were also provided, along with a list of questions to encourage a discussion on the experimental approach and results obtained. The adapted experiments were successful completed and all expected results were obtained in class. Thus the students effectively revisited the classical experiments which revealed that DNA is the genetic material. Also, the class was very well accepted, as indicated by students’ evaluations. Thus, we presented an inexpens ive, quick class involving important concepts, which can be easily reproduced in any laboratory withminor resources.

  8. Chemical genetics reveals a specific requirement for Cdk2 activity in the DNA damage response and identifies Nbs1 as a Cdk2 substrate in human cells.

    Directory of Open Access Journals (Sweden)

    Lara Wohlbold

    2012-08-01

    Full Text Available The cyclin-dependent kinases (CDKs that promote cell-cycle progression are targets for negative regulation by signals from damaged or unreplicated DNA, but also play active roles in response to DNA lesions. The requirement for activity in the face of DNA damage implies that there are mechanisms to insulate certain CDKs from checkpoint inhibition. It remains difficult, however, to assign precise functions to specific CDKs in protecting genomic integrity. In mammals, Cdk2 is active throughout S and G2 phases, but Cdk2 protein is dispensable for survival, owing to compensation by other CDKs. That plasticity obscured a requirement for Cdk2 activity in proliferation of human cells, which we uncovered by replacement of wild-type Cdk2 with a mutant version sensitized to inhibition by bulky adenine analogs. Here we show that transient, selective inhibition of analog-sensitive (AS Cdk2 after exposure to ionizing radiation (IR enhances cell-killing. In extracts supplemented with an ATP analog used preferentially by AS kinases, Cdk2(as phosphorylated the Nijmegen Breakage Syndrome gene product Nbs1-a component of the conserved Mre11-Rad50-Nbs1 complex required for normal DNA damage repair and checkpoint signaling-dependent on a consensus CDK recognition site at Ser432. In vivo, selective inhibition of Cdk2 delayed and diminished Nbs1-Ser432 phosphorylation during S phase, and mutation of Ser432 to Ala or Asp increased IR-sensitivity. Therefore, by chemical genetics, we uncovered both a non-redundant requirement for Cdk2 activity in response to DNA damage and a specific target of Cdk2 within the DNA repair machinery.

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

    Science.gov (United States)

    Trinh, B. T.; Hackl, K.

    2014-07-01

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

  10. An application of cost-effectiveness analysis to restrict the damage caused by accidental release of radioactive material to the environment

    International Nuclear Information System (INIS)

    Frittelli, L.; Tamburrano, A.

    1980-01-01

    A cost-effective analysis is applied to the problem of restricting the damage caused by an accidental release of radioactive material to the environment. The cost of remedial actions is compared with the monetary value of the collective dose avoided by these actions. After describing the methodology used, the results for various 'standard' accidents in PWR are given. Results are also given for various values of the monetary value of health damage ($ per man Sv). If remedial action were managed only on the basis of cost-effective analysis, an intervention plan for reducing social damage would be justified only for large and mean extent accidents; however, no account has been taken of psychological factors. (U.K.)

  11. Helium production for 0.8-2.5 GeV proton induced spallation reactions, damage induced in metallic window materials

    International Nuclear Information System (INIS)

    Hilscher, D.; Herbach, C.-M.; Jahnke, U.; Tishchenko, V.; Enke, M.; Filges, D.; Goldenbaum, F.; Neef, R.-D.; Nuenighoff, K.; Paul, N.; Schaal, H.; Sterzenbach, G.; Letourneau, A.; Boehm, A.; Galin, J.; Lott, B.; Peghaire, A.; Pienkowski, L.

    2001-01-01

    Production cross-sections for neutrons and charged particles as well as excitation energy distributions in spallation reactions were measured recently by the NESSI-collaboration and have been employed to test different intra nuclear cascade models and the subsequent evaporation. The INCL/GEMINI code, which describes best the experimental data has been employed to calculate the damage cross-sections in Fe and Ta as well as the He/dpa ratio as a function of proton energy. For the same amount of neutron production in a typical target of a spallation neutron source the proton beam induced radiation damage in an Fe window is shown to decrease almost linearly with proton energy. For heavier materials such as Ta a similar decrease of the radiation damage is found only for energies above about 3 GeV

  12. Molecular genetics

    International Nuclear Information System (INIS)

    Kubitschek, H.E.

    1975-01-01

    Progress is reported on studies on the nature and action of lethal and mutagenic lesions in DNA and the mechanisms by which these are produced in bacteria by ionizing radiation or by decay of radioisotopes incorporated in DNA. Studies of radioisotope decay provide the advantages that the original lesion is localized in the genetic material and the immediate physical and chemical changes that occur at decay are known. Specific types of DNA damage were related to characteristic decay properties of several radioisotopes. Incorporated 125 I, for example, induces a double-stranded break in DNA with almost every decay, but causes remarkably little damage of any other kind to the DNA. (U.S.)

  13. Development of a genomic DNA reference material panel for myotonic dystrophy type 1 (DM1) genetic testing.

    Science.gov (United States)

    Kalman, Lisa; Tarleton, Jack; Hitch, Monica; Hegde, Madhuri; Hjelm, Nick; Berry-Kravis, Elizabeth; Zhou, Lili; Hilbert, James E; Luebbe, Elizabeth A; Moxley, Richard T; Toji, Lorraine

    2013-07-01

    Myotonic dystrophy type 1 (DM1) is caused by expansion of a CTG triplet repeat in the 3' untranslated region of the DMPK gene that encodes a serine-threonine kinase. Patients with larger repeats tend to have a more severe phenotype. Clinical laboratories require reference and quality control materials for DM1 diagnostic and carrier genetic testing. Well-characterized reference materials are not available. To address this need, the Centers for Disease Control and Prevention-based Genetic Testing Reference Material Coordination Program, in collaboration with members of the genetic testing community, the National Registry of Myotonic Dystrophy and Facioscapulohumeral Muscular Dystrophy Patients and Family Members, and the Coriell Cell Repositories, has established and characterized cell lines from patients with DM1 to create a reference material panel. The CTG repeats in genomic DNA samples from 10 DM1 cell lines were characterized in three clinical genetic testing laboratories using PCR and Southern blot analysis. DMPK alleles in the samples cover four of five DM1 clinical categories: normal (5 to 34 repeats), mild (50 to 100 repeats), classical (101 to 1000 repeats), and congenital (>1000 repeats). We did not identify or establish Coriell cell lines in the premutation range (35 to 49 repeats). These samples are publicly available for quality control, proficiency testing, test development, and research and should help improve the accuracy of DM1 testing. Copyright © 2013 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  14. Application of a Genetic Algorithm and a Neural Network for the Discovery and Optimization of New Solid Catalytic Materials

    Czech Academy of Sciences Publication Activity Database

    Rodemerck, U.; Baerns, M.; Holeňa, Martin; Wolf, D.

    2004-01-01

    Roč. 223, - (2004), s. 168-174 ISSN 0169-4332 Institutional research plan: CEZ:AV0Z1030915 Keywords : genetic algorithm * neural network * catalytic materials Subject RIV: BA - General Mathematics Impact factor: 1.497, year: 2004

  15. Genetics

    International Nuclear Information System (INIS)

    Hubitschek, H.E.

    1975-01-01

    Progress is reported on the following research projects: genetic effects of high LET radiations; genetic regulation, alteration, and repair; chromosome replication and the division cycle of Escherichia coli; effects of radioisotope decay in the DNA of microorganisms; initiation and termination of DNA replication in Bacillus subtilis; mutagenesis in mouse myeloma cells; lethal and mutagenic effects of near-uv radiation; effect of 8-methoxypsoralen on photodynamic lethality and mutagenicity in Escherichia coli; DNA repair of the lethal effects of far-uv; and near uv irradiation of bacterial cells

  16. Damage by radiation in structural materials of BWR reactor vessels; Dano por radiacion en materiales estructurales de vasijas de reactores BWR

    Energy Technology Data Exchange (ETDEWEB)

    Robles, E.; Balcazar, M.; Alpizar, A.M.; Calderon, B.E. [Departamento de Sintesis y Caracterizacion de Materiales, Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2002-07-01

    The structural materials which are manufactured the pressure vessels of the BWR reactors undergo degradation in their mechanical properties mainly due to the damage produced by the fast neutrons (E> 1 MeV) coming from the reactor core. The mechanisms of neutron damage in this type of materials are experimentally studied, through the irradiation of vessel steel in experimental reactors for a quickly ageing. Alternately the neutron damage through steel irradiation with heavy ions is simulated. In this work the first results of the damage induced by irradiation of a similar steel to the vessel of a BWR reactor are shown. The irradiation was performed with fast neutrons (E> 1 MeV, fluence of 1.45 x 10{sup 18} n/cm{sup 2}) in the TRIGA Mark III Salazar reactor and separately with Ni{sup +3} ions in a Tandetrom accelerator (E= 4.8 MeV and an ion flux rank of 0.1 to 53 ions/A{sup 2}). (Author)

  17. Dynamic localisation of mature microRNAs in Human nucleoli is influenced by exogenous genetic materials.

    Directory of Open Access Journals (Sweden)

    Zhou Fang Li

    Full Text Available Although microRNAs are commonly known to function as a component of RNA-induced silencing complexes in the cytoplasm, they have been detected in other organelles, notably the nucleus and the nucleolus, of mammalian cells. We have conducted a systematic search for miRNAs in HeLa cell nucleoli, and identified 11 abundant miRNAs with a high level of nucleolar accumulation. Through in situ hybridisation, we have localised these miRNAs, including miR-191 and miR-484, in the nucleolus of a diversity of human and rodent cell lines. The nucleolar association of these miRNAs is resistant to various cellular stresses, but highly sensitive to the presence of exogenous nucleic acids. Introduction of both single- and double-stranded DNA as well as double stranded RNA rapidly induce the redistribution of nucleolar miRNAs to the cytoplasm. A similar change in subcellular distribution is also observed in cells infected with the influenza A virus. The partition of miRNAs between the nucleolus and the cytoplasm is affected by Leptomycin B, suggesting a role of Exportin-1 in the intracellular shuttling of miRNAs. This study reveals a previously unknown aspect of miRNA biology, and suggests a possible link between these small noncoding RNAs and the cellular management of foreign genetic materials.

  18. Inter-laboratory analysis of selected genetically modified plant reference materials with digital PCR.

    Science.gov (United States)

    Dobnik, David; Demšar, Tina; Huber, Ingrid; Gerdes, Lars; Broeders, Sylvia; Roosens, Nancy; Debode, Frederic; Berben, Gilbert; Žel, Jana

    2018-01-01

    Digital PCR (dPCR), as a new technology in the field of genetically modified (GM) organism (GMO) testing, enables determination of absolute target copy numbers. The purpose of our study was to test the transferability of methods designed for quantitative PCR (qPCR) to dPCR and to carry out an inter-laboratory comparison of the performance of two different dPCR platforms when determining the absolute GM copy numbers and GM copy number ratio in reference materials certified for GM content in mass fraction. Overall results in terms of measured GM% were within acceptable variation limits for both tested dPCR systems. However, the determined absolute copy numbers for individual genes or events showed higher variability between laboratories in one third of the cases, most possibly due to variability in the technical work, droplet size variability, and analysis of the raw data. GMO quantification with dPCR and qPCR was comparable. As methods originally designed for qPCR performed well in dPCR systems, already validated qPCR assays can most generally be used for dPCR technology with the purpose of GMO detection. Graphical abstract The output of three different PCR-based platforms was assessed in an inter-laboratory comparison.

  19. Novel genetically optimised high-displacement piezoelectric actuator with efficient use of active material

    Science.gov (United States)

    Poikselkä, Katja; Leinonen, Mikko; Palosaari, Jaakko; Vallivaara, Ilari; Röning, Juha; Juuti, Jari

    2017-09-01

    This paper introduces a new type of piezoelectric actuator, Mikbal. The Mikbal was developed from a Cymbal by adding steel structures around the steel cap to increase displacement and reduce the amount of piezoelectric material used. Here the parameters of the steel cap of Mikbal and Cymbal actuators were optimised by using genetic algorithms in combination with Comsol Multiphysics FEM modelling software. The blocking force of the actuator was maximised for different values of displacement by optimising the height and the top diameter of the end cap profile so that their effect on displacement, blocking force and stresses could be analysed. The optimisation process was done for five Mikbal- and two Cymbal-type actuators with different diameters varying between 15 and 40 mm. A Mikbal with a Ø 25 mm piezoceramic disc and a Ø 40 mm steel end cap was produced and the performances of unclamped measured and modelled cases were found to correspond within 2.8% accuracy. With a piezoelectric disc of Ø 25 mm, the Mikbal created 72% greater displacement while blocking force was decreased 57% compared with a Cymbal with the same size disc. Even with a Ø 20 mm piezoelectric disc, the Mikbal was able to generate ∼10% higher displacement than a Ø 25 mm Cymbal. Thus, the introduced Mikbal structure presents a way to extend the displacement capabilities of a conventional Cymbal actuator for low-to-moderate force applications.

  20. Biosafety Procedure for Safe Handling of Genetically Modified Plant Materials in Bio Design Facility

    International Nuclear Information System (INIS)

    Zaiton Ahmad; Shuhaimi Shamsudin; Mohamed Najli Mohamed Yasin; Affrida Abu Hassan; Mohd Zaid Hassan; Rusli Ibrahim

    2015-01-01

    Bio Design Facility is the specifically designed glass house for propagation, screening and analysis of high quality plant varieties developed through biotechnology or a combination of nuclear technology and biotechnology. High quality plant varieties especially genetically modified plants (GMO) require a special glass house facility for propagation and screening to isolate them from cross-pollinating with wild type varieties in surrounding ecosystem, and for carrying out evaluation of possible risks of the plants to human, animal and environment before they are proven safe for field trials or commercial release. This facility which was developed under the Ninth Malaysia Plan is classified as the Plant Containment Level 2 and is compliance with the bio safety regulations and guidance for the safe release of GMO according to Malaysian Bio safety Act 2007. Bio Design Facility is fully operational since 2010 and in 2012, it has also been certified as the glass house for post-entry quarantine by The Department of Agriculture. This paper summarizes the bio safety procedure for a safe, controlled and contained growing and evaluation of GMO in Bio Design Facility. This procedure covers the physical (containment and equipment's) and operational (including responsibility, code of practice, growing, decontamination and disposal of plant materials, emergency and contingency plan) aspects of the facility. (author)

  1. Genetics

    DEFF Research Database (Denmark)

    Christensen, Kaare; McGue, Matt

    2016-01-01

    The sequenced genomes of individuals aged ≥80 years, who were highly educated, self-referred volunteers and with no self-reported chronic diseases were compared to young controls. In these data, healthy ageing is a distinct phenotype from exceptional longevity and genetic factors that protect...

  2. Development of a genomic DNA reference material panel for Rett syndrome (MECP2-related disorders) genetic testing.

    Science.gov (United States)

    Kalman, Lisa V; Tarleton, Jack C; Percy, Alan K; Aradhya, Swaroop; Bale, Sherri; Barker, Shannon D; Bayrak-Toydemir, Pinar; Bridges, Christina; Buller-Burckle, Arlene M; Das, Soma; Iyer, Ramaswamy K; Vo, Timothy D; Zvereff, Val V; Toji, Lorraine H

    2014-03-01

    Rett syndrome is a dominant X-linked disorder caused by point mutations (approximately 80%) or by deletions or insertions (approximately 15% to 18%) in the MECP2 gene. It is most common in females but lethal in males, with a distinctly different phenotype. Rett syndrome patients have severe neurological and behavioral problems. Clinical genetic testing laboratories commonly use characterized genomic DNA reference materials to assure the quality of the testing process; however, none are commercially available for MECP2 genetic testing. The Centers for Disease Control and Prevention's Genetic Testing Reference Material Coordination Program, in collaboration with the genetic testing community and the Coriell Cell Repositories, established 27 new cell lines and characterized the MECP2 mutations in these and in 8 previously available cell lines. DNA samples from the 35 cell lines were tested by eight clinical genetic testing laboratories using DNA sequence analysis and methods to assess copy number (multiplex ligation-dependent probe amplification, semiquantitative PCR, or array-based comparative genomic hybridization). The eight common point mutations known to cause approximately 60% of Rett syndrome cases were identified, as were other MECP2 variants, including deletions, duplications, and frame shift and splice-site mutations. Two of the 35 samples were from males with MECP2 duplications. These MECP2 and other characterized genomic DNA samples are publicly available from the NIGMS Repository at the Coriell Cell Repositories. Copyright © 2014 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

  3. Creation of Polyurethane Injection Materials, Their Pilot-industrial Production, Development and Industrial Introduction of the Technology of Strengthening and Restoring the Operability of Damaged Constructions and Buildings

    Directory of Open Access Journals (Sweden)

    Marukha, V.І.

    2015-01-01

    Full Text Available Polyurethane and foam polyurethane fluid injection materials not conceding foreign analogues and technology technology of restoration and strengthening the operability of concrete and reinforced concrete structures and buildings damaged by cracks were developed. Normative and technical documentation on the injection materials and technological processes was created. The diagnosticrestoring complex for implementing the above technologies was designed, installed and utilized at the construction sites. The equipment is designed and manufactured; the technology of the research and industrial production of «A» and «B» components of injecting polyurethane materials is designed and developed. The pilot-scale batch is manufactured. Technological processes of preparation and application of the «A» and «B» componentsof the injecting materials in industrial conditions are worked out and implemented.

  4. Evaluation of terrestrial microcosms for detection, fate, and survival analysis of genetically engineered microorganisms and their recombinant genetic material

    Energy Technology Data Exchange (ETDEWEB)

    Fredrickson, J.K.; Seidler, R.J.

    1989-02-01

    The research included in this document represents the current scientific information available regarding the applicability of terrestrial microcosms and related methodologies for evaluating detection methods and the fate and survival of microorganisms in the environment. The three terrestrial microcosms described in this document were used to evaluate the survival and fate of recombinant bacteria in soils and in association with plant surfaces and insects and their transport through soil with percolating water and root systems, and to test new methods and procedures to improve detection and enumeration of bacteria in soil. Simple (potting soil composed of peat mix and perlite, lacking environmental control and monitoring) and complex microcosms (agricultural soil with partial control and monitoring of environmental conditions) were demonstrated to be useful tools for preliminary assessments of microbial viability in terrestrial ecosystems. These studies evaluated the survival patterns of Enterobacter cloacae (pBR322) in soil and on plant surfaces and the ingestion of this same microorganism by cutworms and survival in the foregut and frass. The Versacore microcosm design was used to monitor the fate and competitiveness of genetically engineered bacteria in soil. Both selective media and gene probes were used successfully to follow the fate of two recombinant Pseudomonas sp. introduced into Versacore microcosms. Intact soil-core microcosms were employed to evaluate the fate and transport of genetically altered Azospirillum sp. and Pseudomonas sp. in soil and the plant rhizosphere. The usefulness of these various microcosms as a tool for risk assessment is underscored by the ease in obtaining soil from a proposed field release site to evaluate subsequent GEM fate and survival.

  5. THz absorption signature detection of genetic material of E. coli and B. subtilis

    Science.gov (United States)

    Bykhovski, Alexei; Li, Xiaowei; Globus, Tatiana; Khromova, Tatyana; Gelmont, Boris; Woolard, Dwight; Samuels, Alan C.; Jensen, James O.

    2005-11-01

    The development of efficient biological agent detection techniques requires in-depth understanding of THz absorption spectral features of different cell components. Chromosomal DNA, RNAs, proteins, bacterial cell wall, proteinaceous coat might be essential for bacterial cells and spores THz signature. As a first step, the DNA's contribution into entire cell THz spectra was analyzed. The experimental study of cells and DNAs of E. coli and cells/spores and DNA of Bacillus subtilis was conducted. Samples were prepared in the form of water solutions (suspension) with the concentrations in the range 0.01-1 mg/ml. The measurable difference in the THz transmission spectra of E. coli and Bacillus subtilis DNAs was observed. The correlation between chromosomal DNA signature and a corresponding entire spore/cell signature was observed. This correlation was especially pronounced for spores of Bacillus subtilis and their DNA. These experimental results justify our approach to develop a model for THz signatures of biological simulants and agents. In parallel with the experimental study, for the first time, the computer modeling and simulation of chromosome DNAs of E. coli and Bacillus subtilis was performed and their THz signatures were calculated. The DNA structures were optimized using the Amber software package. Also, we developed the initial model of the DNA fragment poly(dAT)-poly(dTA) solvated in water to be used in the simulations of genetic material (DNA and RNA) of spores and cells. Molecular dynamical simulations were conducted using explicit solvent (3-point TIP3P water) and implicit solvent (generalized Born) models. The calculated THz signatures of E. coli and Bacillus subtilis DNAs and poly(dAT)-poly(dTA) reproduce many features of our measured spectra. The results of this study demonstrate that THz Fourier transform infrared spectroscopy is a promising tool in generating spectral data for complex biological objects such as bacterial cells and spores.

  6. Initial evaluation and comparison of plasma damage to atomic layer carbon materials using conventional and low T{sub e} plasma sources

    Energy Technology Data Exchange (ETDEWEB)

    Jagtiani, Ashish V.; Miyazoe, Hiroyuki; Chang, Josephine; Farmer, Damon B.; Engel, Michael; Neumayer, Deborah; Han, Shu-Jen; Engelmann, Sebastian U., E-mail: suengelm@us.ibm.com; Joseph, Eric A. [IBM, T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Boris, David R.; Hernández, Sandra C.; Walton, Scott G. [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States); Lock, Evgeniya H. [Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375 (United States)

    2016-01-15

    The ability to achieve atomic layer precision is the utmost goal in the implementation of atomic layer etch technology. Carbon-based materials such as carbon nanotubes (CNTs) and graphene are single atomic layers of carbon with unique properties and, as such, represent the ultimate candidates to study the ability to process with atomic layer precision and assess impact of plasma damage to atomic layer materials. In this work, the authors use these materials to evaluate the atomic layer processing capabilities of electron beam generated plasmas. First, the authors evaluate damage to semiconducting CNTs when exposed to beam-generated plasmas and compare these results against the results using typical plasma used in semiconductor processing. The authors find that the beam generated plasma resulted in significantly lower current degradation in comparison to typical plasmas. Next, the authors evaluated the use of electron beam generated plasmas to process graphene-based devices by functionalizing graphene with fluorine, nitrogen, or oxygen to facilitate atomic layer deposition (ALD). The authors found that all adsorbed species resulted in successful ALD with varying impact on the transconductance of the graphene. Furthermore, the authors compare the ability of both beam generated plasma as well as a conventional low ion energy inductively coupled plasma (ICP) to remove silicon nitride (SiN) deposited on top of the graphene films. Our results indicate that, while both systems can remove SiN, an increase in the D/G ratio from 0.08 for unprocessed graphene to 0.22 to 0.26 for the beam generated plasma, while the ICP yielded values from 0.52 to 1.78. Generally, while some plasma-induced damage was seen for both plasma sources, a much wider process window as well as far less damage to CNTs and graphene was observed when using electron beam generated plasmas.

  7. Laser Induced Damage in Optical Materials: 1983. Symposium on Optical Materials for High Power Lasers (15th). Held in Boulder, Colorado on 14-16 November 1983

    Science.gov (United States)

    1985-11-01

    cleaning. In a typical cleansing , the substrate was soaked in mild acids or bases, scrubbed with rotary brushes while immersed in a solution of water...the field, presented a discourse on the inherent mechanical damage in diamond-turned optical sur faces . In referring to works dating back to 1665...determine the temperature pro­ file in the axial and radial directions. For this purpose, we model the window as a disc with two circular faces

  8. Aspergillus fumigatus spore proteomics and genetics reveal that VeA represses DefA-mediated DNA damage response.

    Science.gov (United States)

    Shin, Kwang-Soo; Park, Hee-Soo; Kim, Young; Heo, In-Beom; Kim, Young Hwan; Yu, Jae-Hyuk

    2016-10-04

    Aspergillus fumigatus reproduces and infects host by forming a high number of small asexual spores (conidia). The velvet proteins are global transcriptional regulators governing the complex process of conidiogenesis in this fungus. Here, to further understand the velvet-mediated regulation, we carried out comparative proteomic analyses of conidia of wild type (WT) and three velvet mutants (ΔveA, ΔvelB and ΔvosA). Cluster analysis of 184 protein spots showing at least 1.5-fold differential accumulation between WT and mutants reveal the clustering of WT- ΔveA and ΔvelB-ΔvosA. Among 43 proteins identified by Nano-LC-ESI-MS/MS, 23 including several heat shock proteins showed more than two-fold reduction in both the ∆velB and ∆vosA conidia. On the contrary, three proteins exhibited more than five-fold increase in ∆veA only, including the putative RNA polymerase II degradation factor DefA. The deletion of defA resulted in a reduced number of conidia and restricted colony growth. In addition, the defA deletion mutant conidia showed hypersensitivity against the DNA damaging agents NQO and MMS, while the ΔveA mutant conidia were more resistant against to NQO. Taken together, we propose that VeA controls protein level of DefA in conidia, which are dormant and equipped with multiple layers of protection against environmental cues. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Damage evaluation of laminated composite material using a new acoustic emission Lamb-based and finite element techniques

    Science.gov (United States)

    Yousefi, Jalal; Najfabadi, Mehdi Ahmadi; Toudeshky, Hossein Hosseini; Akhlaghi, Mehdi

    2017-10-01

    In this paper, a very promising procedure is proposed to evaluate delamination using Acoustic Emission (AE) technique in composite laminates. First, a new procedure was developed to decompose the fundamental Lamb wave modes in small size specimens. The damage mechanisms in End Notched Flexure (ENF) in woven and unidirectional specimens were then discriminated using Fuzzy Clustering Method (FCM). Afterwards, the crack-arrest phenomenon was examined in each specimen. After that, experimental and Cohesive Zone Modeling (CZM) techniques were conducted to characterize the delamination using ENF specimens. The results showed how, it is possible to successfully decrease the effect of propagating media such as attenuation of AE signals using the new proposed methodology. As a final point, the results of this study could lead to efficiently distinguishing different damages in laminated composite using AE Lamb-based technique.

  10. Design of an ultra-thin absorption layer with magnetic materials based on genetic algorithm at the S band

    Science.gov (United States)

    Wang, Fang; Yang, Xiaoning; Liu, Xiaoning; Niu, Tiaoming; Wang, Jing; Mei, Zhonglei; Jian, Yabin

    2018-04-01

    In this work, we design an ultra-thin absorption coating at the S band, and the total thickness is less than 2 mm. For incident angle less than 30 degree and the whole S band, the reflection is less than -5 dB. The coating is constructed with 4/3 layers of magnetic material with different thicknesses, which are optimized by using genetic algorithm. Analytic and simulation results confirm the correctness of the design.

  11. Developing a Material Response Model of Biopolymer-Stabilized Regolith to Predict Micrometeorite Damage of ISRU Habitat Systems

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed space technology research aims to investigate the micrometeorite impact performance of Regolith Biocomposite (RBC), an innovative in-situ material...

  12. Protective or damage promoting effect of calcium carbonate layers on the surface of cement based materials in aqueous environments

    International Nuclear Information System (INIS)

    Schwotzer, M.; Scherer, T.; Gerdes, A.

    2010-01-01

    Cement based materials permanently exposed to aggressive aqueous environments are subject to chemical changes affecting their durability. However, this holds also for tap water that is considered to be not aggressive to cementitious materials, although in that case a formation of covering layers of CaCO 3 on the alkaline surfaces is commonly supposed to provide protection against reactive transport processes. Thus, investigations of the structural and chemical properties of the material/water interface were carried out in laboratory experiments and case studies to elucidate the consequences of surface reactions for the durability of cement based materials exposed to tap water. Focused Ion Beam investigations revealed that a protective effect of a CaCO 3 covering layer depends on its structural properties, which are in turn affected by the hydro-chemical conditions during crystallization. Surface precipitation of CaCO 3 can trigger further chemical degradation, if the required calcium is supplied by the pore solution of the material.

  13. Simulations of dynamic crack propagation in brittle materials using nodal cohesive forces and continuum damage mechanics in the distinct element code LDEC

    Energy Technology Data Exchange (ETDEWEB)

    Block, G I; Rubin, M B; Morris, J P; Berryman, J G

    2006-08-23

    Experimental data indicates that the limiting crack speed in brittle materials is less than the Rayleigh wave speed. One reason for this is that dynamic instabilities produce surface roughness and microcracks that branch from the main crack. These processes increase dissipation near the crack tip over a range of crack speeds. When the scale of observation (or mesh resolution) becomes much larger than the typical sizes of these features, effective-medium theories are required to predict the coarse-grained fracture dynamics. Two approaches to modeling these phenomena are described and used in numerical simulations. The first approach is based on cohesive elements that utilize a rate-dependent weakening law for the nodal cohesive forces. The second approach uses a continuum damage model which has a weakening effect that lowers the effective Rayleigh wave speed in the material surrounding the crack tip. Simulations in this paper show that while both models are capable of increasing the energy dissipated during fracture when the mesh size is larger than the process zone size, only the continuum damage model is able to limit the crack speed over a range of applied loads. Numerical simulations of straight-running cracks demonstrate good agreement between the theoretical predictions of the combined models and experimental data on dynamic crack propagation in brittle materials. Simulations that model crack branching are also presented.

  14. Reduction of radiation damage on organic material at very low object temperatures in an electron microscope with supraconductive lenses

    International Nuclear Information System (INIS)

    Knapek, E.

    1981-01-01

    As a result of this study, the increase in structure conservation by cooling the object to very low temperatures (cryoprotection) as compared with the conditions at room temperature was higher than the values at low temperatures reached so far by one to two orders of magnitude. The experiments carried out with an electron microscope with supraconductive lenses (SLEM) showed, depending of the organic substance, that in tests with an electron diffraction of about 4.2 K the reduction of radiation damage as compared with room temperature was by a factor between 30 and 350. (orig./PW) [de

  15. Wavelength dependence of the damage threshold of inorganic materials under extreme-ultraviolet free-electron-laser irradiation

    Czech Academy of Sciences Publication Activity Database

    Hau-Riege, S.P.; London, R.A.; Bionta, R.M.; Ryutov, D.; Soufli, R.; Bajt, S.; McKernan, M.A.; Baker, S. L.; Krzywinski, J.; Sobierajski, R.; Nietubyc, R.; Klinger, D.; Pelka, J. B.; Jurek, M.; Juha, Libor; Chalupský, Jaromír; Cihelka, Jaroslav; Hájková, Věra; Velyhan, Andriy; Krása, Josef; Tiedtke, K.; Toleikis, S.; Wabnitz, H.; Bergh, M.; Caleman, C.; Timneanu, N.

    2009-01-01

    Roč. 95, č. 11 (2009), 111104/1-111104/3 ISSN 0003-6951 R&D Projects: GA AV ČR KAN300100702; GA MŠk LC510; GA MŠk(CZ) LC528; GA MŠk LA08024; GA AV ČR IAA400100701 Institutional research plan: CEZ:AV0Z10100523 Keywords : damage threshold * silicon carbide * boron carbide * soft X- ray free-electron laser Subject RIV: BH - Optics, Masers, Lasers Impact factor: 3.554, year: 2009

  16. Development of Meandering Winding Magnetometer (MWM (Register Trademark)) Eddy Current Sensors for the Health Monitoring, Modeling and Damage Detection of High Temperature Composite Materials

    Science.gov (United States)

    Russell, Richard; Washabaugh, Andy; Sheiretov, Yanko; Martin, Christopher; Goldfine, Neil

    2011-01-01

    The increased use of high-temperature composite materials in modern and next generation aircraft and spacecraft have led to the need for improved nondestructive evaluation and health monitoring techniques. Such technologies are desirable to improve quality control, damage detection, stress evaluation and temperature measurement capabilities. Novel eddy current sensors and sensor arrays, such as Meandering Winding Magnetometers (MWMs) have provided alternate or complimentary techniques to ultrasound and thermography for both nondestructive evaluation (NDE) and structural health monitoring (SHM). This includes imaging of composite material quality, damage detection and .the monitoring of fiber temperatures and multidirectional stresses. Historically, implementation of MWM technology for the inspection of the Space Shuttle Orbiter Reinforced Carbon-Carbon Composite (RCC) leading edge panels was developed by JENTEK Sensors and was subsequently transitioned by NASA as an operational pre and post flight in-situ inspection at the Kennedy Space Center. A manual scanner, which conformed'automatically to the curvature of the RCC panels was developed and used as a secondary technique if a defect was found during an infrared thermography screening, During a recent proof of concept study on composite overwrapped pressure vessels (COPV's), three different MWM sensors were tested at three orientations to demonstrate the ability of the technology to measure stresses at various fiber orientations and depths. These results showed excellent correlation with actual surface strain gage measurements. Recent advancements of this technology have been made applying MWM sensor technology for scanning COPVs for mechanical damage. This presentation will outline the recent advance in the MWM.technology and the development of MWM techniques for NDE and SHM of carbon wraped composite overwrapped pressure vessels (COPVs) including the measurement of internal stresses via a surface mounted sensor

  17. Quality assurance for Duchenne and Becker muscular dystrophy genetic testing: development of a genomic DNA reference material panel.

    Science.gov (United States)

    Kalman, Lisa; Leonard, Jay; Gerry, Norman; Tarleton, Jack; Bridges, Christina; Gastier-Foster, Julie M; Pyatt, Robert E; Stonerock, Eileen; Johnson, Monique A; Richards, C Sue; Schrijver, Iris; Ma, Tianhui; Miller, Vanessa Rangel; Adadevoh, Yetsa; Furlong, Pat; Beiswanger, Christine; Toji, Lorraine

    2011-03-01

    Duchenne and Becker muscular dystrophies (DMD/BMD) are allelic X-linked recessive disorders that affect approximately 1 in 3500 and 1 in 20,000 male individuals, respectively. Approximately 65% of patients with DMD have deletions, 7% to 10% have duplications, and 25% to 30% have point mutations in one or more of the 79 exons of the dystrophin gene. Most clinical genetics laboratories test for deletions, and some use technologies that can detect smaller mutations and duplications. Reference and quality control materials for DMD/BMD diagnostic and carrier genetic testing are not commercially available. To help address this need, the Centers for Disease Control and Prevention-based Genetic Testing Reference Material Coordination Program, in collaboration with members of the genetic testing and the DMD/BMD patient communities and the Coriell Cell Repositories, have characterized new and existing cell lines to create a comprehensive DMD/BMD reference material panel. Samples from 31 Coriell DMD cell lines from male probands and female carriers were analyzed using the Affymetrix SNP Array 6.0 and Multiplex Ligation-Dependent Probe Amplification (MRC-Holland BV, Amsterdam, the Netherlands), a multiplex PCR assay, and DNA sequence analysis. Identified were 16 cell lines with deletions, 9 with duplications, and 4 with point mutations distributed throughout the dystrophin gene. There were no discordant results within assay limitations. These samples are publicly available from Coriell Institute for Medical Research (Camden, NJ) and can be used for quality assurance, proficiency testing, test development, and research, and should help improve the accuracy of DMD testing. Copyright © 2011 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

  18. Long-Term Strength of a Thick-Walled Pipe Filled with an Aggressive Medium, with Account for Damageability of the Pipe Material and Residual Strength

    Science.gov (United States)

    Piriev, S. A.

    2018-01-01

    This paper describes the study of scattered fracture of a thick-walled pipe filled with an aggressive medium, which creates uniform pressure on the inner surface of the pipe. It is assumed that the aggressive medium affects only the value of instantaneous strength. Damageability is described by an integral operator of the hereditary type. The problem is solved with allowance for residual strength of the pipe material behind the fracture front. Numerical calculation is carried out, and relationships between the fracture front coordinate and time for various concentrations of the aggressive medium and residual strength behind the fracture front are constructed.

  19. Multi-Axial Damage Index and Accumulation Model for Predicting Fatigue Life of CMC Materials, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The fatigue life of CMCs must be well characterized for the safe and reliable use of these materials as integrated TPS components. Existing fatigue life prediction...

  20. Using ParaPost Tenax fiberglass and ParaCore build-up material to restore severely damaged teeth.

    Science.gov (United States)

    Caicedo, Ricardo; Castellon, Paulino

    2005-01-01

    This article describes a technique using ParaPost Tenax Fiber White, ParaPost Cement, and ParaPost ParaCore build-up material to restore a tooth with a significant loss of tooth structure. After successful root canal therapy, the posts were bonded in the canals and the core was built using ParaPost ParaCore build-up material. At that point, the tooth was prepared to receive a conventional porcelain-fused-to-metal crown.

  1. Factors affecting the exchange of genetic material between Nordic and US Holstein populations

    DEFF Research Database (Denmark)

    Buch, Line Hjortø; Sørensen, A.C.; Lassen, Jan

    2009-01-01

    be explained by differences in economic values, trait definitions, national genetic evaluation procedures, and genotype x environment interactions. The objective of this study was to test whether uniform definitions of the female fertility traits would increase the exchange of genes across populations......, and to quantify the effect on genetic gain. A second objective was to test whether a more similar relative weighting of the index traits across populations would increase the exchange of genes across populations, and to quantify the effect on genetic gain. This was done in a stochastic simulation study......The possibility of profitable cooperation between dairy cattle populations depends on several factors. Among these factors is the similarity of breeding goals, for example, as measured by the correlations between selection indices. Correlations between selection indices less than unity can usually...

  2. Tungsten as a plasma-facing material in fusion devices: impact of helium high-temperature irradiation on hydrogen retention and damages in the material

    Science.gov (United States)

    Bernard, E.; Sakamoto, R.; Kreter, A.; Barthe, M. F.; Autissier, E.; Desgardin, P.; Yamada, H.; Garcia-Argote, S.; Pieters, G.; Chêne, J.; Rousseau, B.; Grisolia, C.

    2017-12-01

    Plasma-facing materials for next generation fusion devices, like ITER and DEMO, have to withstand intense fluxes of light elements (notably helium and hydrogen isotopes). For tungsten (W), helium (He) irradiation leads to major changes in the material morphology, rising concerns about properties such as material structure conservation and hydrogen (H) retention. The impact of preceeding He irradiation conditions (temperature, flux and fluence) on H trapping were investigated on a set of W samples exposed to the linear plasma device PSI-2. Positron annihilation spectroscopy (PAS) was carried out to probe the free volume of defects created by the He exposure in the W structure at the atomic scale. In parallel, tritium (T) inventory after exposure was evaluated through T gas loading and desorption at the Saclay Tritium Lab. First, we observed that the material preparation prior to He irradiation was crucial, with a major reduction of the T trapping when W was annealed at 1773 K for 2 h compared to the as-received material. PAS study confirms the presence of He in the bubbles created in the material surface layer, whose dimensions were previously characterized by transmission electron microscopy and grazing-incidence small-angle x-ray scattering, and demonstrates that even below the minimal energy for displacement of He in W, defects are created in almost all He irradiation conditions. The T loading study highlights that increasing the He fluence leads to higher T inventory. Also, for a given fluence, increasing the He flux reduces the T trapping. The very first steps of a parametric study were set to understand the mechanisms at stake in those observed material modifications, confirming the need to pursue the study with a more complete set of surface and irradiation conditions.

  3. [Studies of the repair of radiation-induced genetic damage in Drosophila]. Annual progress report, October 1, 1988--June 1, 1989

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1989-12-31

    The primary goal of this study is to achieve a more thorough understanding of the mechanisms employed by higher organisms to repair DNA damage induced by both ionizing and nonionizing radiation. These studies are also contributing to an improved understanding of the processes of mutagenesis and carcinogenesis in higher eukaryotes. The studies employ Drosophila as a model organism for investigating repair functions that are common to all higher eukaryotes. Drosophila was chosen in the early phases of this study primarily because of the ease with which one can isolate and characterize repair-deficient mutants in a metazoan organism. The laboratory has gone on to investigate the metabolic defects of such mutants while others have performed complementary genetic and cytogenetic studies which relate DNA repair processes to mutagenesis and chromosome stability. The repair studies have exploited the capacity to introduce mutant Drosophila cells into tissue culture and thereby compare repair defects directly with those of homologous human disorders. Researchers are currently employing recombinant DNA technology to investigate the mechanisms of the DNA repair pathways defined by those mutants.

  4. Fatigue damage evolution in quasi-unidirectional non-crimp fabric based composite materials for wind turbine blades

    DEFF Research Database (Denmark)

    Mikkelsen, Lars Pilgaard

    to be controlled by local architecture of the socalled backing bundle structure present in the non-crimp fabric. This mechanism is demonstrated to be highly dependent on the presence of curing induced residual stresses. Residual stresses which for an epoxy matrix system can be controlled by the chosen cure profile......The fatigue failure of wind turbine blades is controlled by failure mechanisms on multiple scales spanning single fiber fatigue failure at the sub-micron scale, over the fiber bundle structure on the millimeter scale to the quasi-unidirectional non-crimp fabric on the meter scale. At the smaller...... scales, the 3D x-ray computer tomography technique is used non-destructive to observe the fatigue damage evolution on the fiber and bundle scale. Those observations are then linked to the larger scales through mechanical testing of representative volumes of the non-crimp fabric bundle structure...

  5. Determining the molecular origin of radiation damage/enhancement in electro-optic polymeric materials through polarized light microscopy

    Science.gov (United States)

    Perez-Moreno, Javier

    2014-09-01

    Previous studies on the radiation effects upon polymer and polymer-based photonic materials suggest that the radiation resistance of the material is heavily dependent on the choice of polymer-host and guest-chromophore. The best results to date have been achieved with electro optic polymeric materials based on CLD1 doped in APC, which has resulted in improved performance at the device level upon gamma-ray irradiation at moderate doses. Still, our understanding of the physical mechanisms behind the enhancement of the performance is unclear. In this paper, we discuss how polarized light microscopy could be used as a means to quantify the effect of the different physical parameters that influence the optical response of electro-optic polymeric thin film samples.

  6. Genetic relation of adamantanes from extracts and semicoking tars of lignites with the initial biological material

    Energy Technology Data Exchange (ETDEWEB)

    Platonov, V.V.; Shvykin, A.Y.; Proskuryakov, V.A.; Podshibyakin, S.I. [Lev Tolstoi State Pedagogical University, Tula (Russian Federation)

    1999-11-01

    A genetic relation was revealed of adamantanes from extracts and semicoking tars of lignites with the relic terpenoid and steroid compounds. Probable pathways are suggested for transformation of the initial natural structures into adamantanes. The qualitative and quantitative compositions of adamantanes from crude oil and coal are compared.

  7. Genetically modified crops and the “food crisis”: discourse and material impacts

    NARCIS (Netherlands)

    Glover, D.; Stone, G.D.

    2011-01-01

    A surge of media reports and rhetorical claims depicted genetically modified (GM) crops as a solution to the ‘global food crisis’ manifested in the sudden spike in world food prices during 2007–08. Broad claims were made about the potential of GM technologies to tackle the crisis, even though the

  8. The Winding Road to Discovering the Link between Genetic Material and DNA

    Science.gov (United States)

    Cherif, Abour H.; Roze, Maris; Movahedzadeh, Farahnaz

    2015-01-01

    This is an account of the three-centuries long journey to the discovery of the link between DNA and the transformation principle of heredity beginning with the discovery of the cell in 1665 and leading up to the 1953 discovery of the genetic code and the structure of DNA. This account also illustrates the way science works and how scientists do…

  9. Hybrid attribute-based recommender system for learning material using genetic algorithm and a multidimensional information model

    Directory of Open Access Journals (Sweden)

    Mojtaba Salehi

    2013-03-01

    Full Text Available In recent years, the explosion of learning materials in the web-based educational systems has caused difficulty of locating appropriate learning materials to learners. A personalized recommendation is an enabling mechanism to overcome information overload occurred in the new learning environments and deliver suitable materials to learners. Since users express their opinions based on some specific attributes of items, this paper proposes a hybrid recommender system for learning materials based on their attributes to improve the accuracy and quality of recommendation. The presented system has two main modules: explicit attribute-based recommender and implicit attribute-based recommender. In the first module, weights of implicit or latent attributes of materials for learner are considered as chromosomes in genetic algorithm then this algorithm optimizes the weights according to historical rating. Then, recommendation is generated by Nearest Neighborhood Algorithm (NNA using the optimized weight vectors implicit attributes that represent the opinions of learners. In the second, preference matrix (PM is introduced that can model the interests of learner based on explicit attributes of learning materials in a multidimensional information model. Then, a new similarity measure between PMs is introduced and recommendations are generated by NNA. The experimental results show that our proposed method outperforms current algorithms on accuracy measures and can alleviate some problems such as cold-start and sparsity.

  10. Finite element simulations and experiments to determine the residual damage of a CFRP composite material after ballistic impacts

    NARCIS (Netherlands)

    Herlaar, K.; Jagt-Deutekom, M. van der

    2005-01-01

    The use of lightweight systems is essential for future combat systems. More and more steel structures are replaced by composite structures. This also influences the vulnerability of the platform. A finite element material model is created in Autodyn of the carbon fiber reinforced plastic (CFRP)

  11. A novel approach towards fatigue damage prognostics of composite materials utilizing SHM data and stochastic degradation modeling

    NARCIS (Netherlands)

    Loutas, T.; Eleftheroglou, N.

    2016-01-01

    A prognostic framework is proposed in order to estimate the remaining useful life of composite materials under fatigue loading based on acoustic emission data and a sophisticated Non Homogenous Hidden Semi Markov Model. Bayesian neural networks are also utilized as an alternative machine learning

  12. Damage analysis: damage function development and application

    International Nuclear Information System (INIS)

    The derivation and application of damage functions, including recent developments for the U.S. LMFBR and CTR programs, is reviewed. A primary application of damage functions is in predicting component life expectancies; i.e., the fluence required in a service spectrum to attain a specified design property change. An important part of the analysis is the estimation of the uncertainty in such fluence limit predictions. The status of standardizing the procedures for the derivation and application of damage functions is discussed. Improvements in several areas of damage function development are needed before standardization can be completed. These include increasing the quantity and quality of the data used in the analysis, determining the limitations of the analysis due to the presence of multiple damage mechanisms, and finally, testing of damage function predictions against data obtained from material surveillance programs in operating thermal and fast reactors. 23 references. (auth)

  13. Introgression of genetic material from Zea mays ssp. Mexicana into cultivated maize was facilitated by tissue culture

    International Nuclear Information System (INIS)

    Wang, L.; Gu, X.; Qu, M.; Luan, J.; Zhang, J.

    2012-01-01

    Zea mays ssp. mexicana, a wild relative of cultivated maize (Z. mays ssp. mays), is a useful gene resource for maize breeding. In this study, two populations were generated by conventional breeding scheme (population I) or tissue culture regime (population II), respectively, to introgress genetic material of Z. mays ssp. mexicana into maize. Karyotype analysis showed that the arm ratios of 10 pairs of chromosomes in parent maize Ye515 and derivative lines from 2 different populations with 26% and 38% chromosome variation frequencies, respectively. Alien chromatin was detected in the root tip cells of progeny plants through genomic in situ hybridization (GISH). There were 3.3 chromosomes carrying alien chromatin on average in population I and 6.5 in population II. The hybridization signals were located mainly at the terminal or sub terminal regions of the chromosomes and the sizes were notably variant among lines. Based on those results, it is concluded that the introgression of genetic material from Z. mays ssp. mexicana into cultivated maize was facilitated by tissue culture, and subsequently some excellent materials for maize breeding were created. (author)

  14. Synthesis, growth and characterization of o-phenylinediaminium benzilate: An SHG material with high laser damage threshold for NLO applications

    Science.gov (United States)

    Rajkumar, M.; Chandramohan, A.

    2017-02-01

    An organic molecular charge transfer complex salt, o-phenylenediaminium benzilate was synthesized and single crystals grown by slow solvent evaporation solution growth technique in methanol at ambient temperature. The grown crystal was subjected to Single crystal XRD analysis to establish the molecular structure. The molecular structure was further confirmed by 1H and 13C NMR spectral studies. The formation of the charge transfer complex salt was confirmed by UV-VIS spectroscopic technique. To identify the optical transmittance window and lower wavelength cut-off, the crystal was subjected to UV-Vis-NIR transmission spectral studies. The presence of various functional groups in the salt crystal was confirmed by FT-IR spectroscopic technique. Photoluminescence study was carried out to explore its efficiency towards device fabrications. The TG and DTA thermal analyses were simultaneously carried out to establish the thermal stability of the crystal. The dielectric studies of the grown crystal were executed at different temperatures as a function of frequency to investigate its electrical properties. The SHG efficiency of the crystal was determined using the modified Kurtz and Perry powder technique and its value was found to be 1.98 times that of the KDP crystal. Laser damage threshold value was measured using Nd:YAG laser. The mechanical stability of the title crystal was established employing Vickers micro hardness tester.

  15. Integrated Prediction and Mitigation Methods of Materials Damage and Lifetime Assessment during Plasma Operation and Various Instabilities in Fusion Devices

    International Nuclear Information System (INIS)

    Hassanein, Ahmed

    2015-01-01

    This report describes implementation of comprehensive and integrated models to evaluate plasma material interactions during normal and abnormal plasma operations. The models in full3D simulations represent state-of-the art worldwide development with numerous benchmarking of various tokamak devices and plasma simulators. In addition, significant number of experimental work has been performed in our center for materials under extreme environment (CMUXE) at Purdue to benchmark the effect of intense particle and heat fluxes on plasma-facing components. This represents one-year worth of work and resulted in more than 23 Journal Publications and numerous conferences presentations. The funding has helped several students to obtain their M.Sc. and Ph.D. degrees and many of them are now faculty members in US and around the world teaching and conducting fusion research. Our work has also been recognized through many awards.

  16. Integrated Prediction and Mitigation Methods of Materials Damage and Lifetime Assessment during Plasma Operation and Various Instabilities in Fusion Devices

    Energy Technology Data Exchange (ETDEWEB)

    Hassanein, Ahmed [Purdue Univ., West Lafayette, IN (United States)

    2015-03-31

    This report describes implementation of comprehensive and integrated models to evaluate plasma material interactions during normal and abnormal plasma operations. The models in full3D simulations represent state-of-the art worldwide development with numerous benchmarking of various tokamak devices and plasma simulators. In addition, significant number of experimental work has been performed in our center for materials under extreme environment (CMUXE) at Purdue to benchmark the effect of intense particle and heat fluxes on plasma-facing components. This represents one-year worth of work and resulted in more than 23 Journal Publications and numerous conferences presentations. The funding has helped several students to obtain their M.Sc. and Ph.D. degrees and many of them are now faculty members in US and around the world teaching and conducting fusion research. Our work has also been recognized through many awards.

  17. Genetic and Biochemical Basis for the Transformation of Energetic Materials (RDX, TNT, DNTs) by Plants

    Science.gov (United States)

    2007-04-01

    Determining the Genetics and Biochemistry of the Phytoremediation Transformation Pathways of RDX and TNT,” Food, Pharmaceutical and Bioengineering...Organic toxicants and plants. Ecotoxicology and Environmental Safety 47:1-26 Larson SL, Jones RP, Escalon L, Parker D (1999) Classification of explosives...dollars, compared to the pharmaceutical industry at 109 billion US dollars (McCutcheon and Schnoor, 2003). Since phytoremediation has minimal capital

  18. Role of genetic polymorphisms of CYP1A1, CYP3A5, CYP2C9, CYP2D6, and PON1 in the modulation of DNA damage in workers occupationally exposed to organophosphate pesticides

    International Nuclear Information System (INIS)

    Singh, Satyender; Kumar, Vivek; Vashisht, Kapil; Singh, Priyanka; Banerjee, Basu Dev; Rautela, Rajender Singh; Grover, Shyam Sunder; Rawat, Devendra Singh; Pasha, Syed Tazeen; Jain, Sudhir Kumar; Rai, Arvind

    2011-01-01

    Organophosphate pesticides (OPs) are primarily metabolized by several xenobiotic metabolizing enzymes (XMEs). Very few studies have explored genetic polymorphisms of XMEs and their association with DNA damage in pesticide-exposed workers. The present study was designed to determine the role of genetic polymorphisms of CYP1A1, CYP3A5, CYP2C9, CYP2D6, and PON1 in the modulation of DNA damage in workers occupationally exposed to OPs. We examined 284 subjects including 150 workers occupationally exposed to OPs and 134 normal healthy controls. The DNA damage was evaluated using the alkaline comet assay and genotyping was done using PCR–RFLP. The results revealed that the PONase activity toward paraoxonase and AChE activity was found significantly lowered in workers as compared to control subjects (p < 0.001). Workers showed significantly higher DNA damage compared to control subjects (14.37 ± 2.15 vs. 6.24 ± 1.37 tail% DNA, p < 0.001). Further, the workers with CYP2D6*3 PM and PON1 (QQ and MM) genotypes were found to have significantly higher DNA damage when compared to other genotypes (p < 0.05). In addition, significant increase in DNA damage was also observed in workers with concomitant presence of certain CYP2D6 and PON1 (Q192R and L55M) genotypes which need further extensive studies. In conclusion, the results indicate that the PON1 and CYP2D6 genotypes can modulate DNA damage elicited by some OPs possibly through gene-environment interactions. -- Highlights: ► Role of CYP1A1, CYP3A5, CYP2C, CYP2D6 and PON1 genotypes on DNA damage. ► Workers exposed to some OPs demonstrated increased DNA damage. ► CYP2D6 *3 PM and PON1 (Q192R and L55M) genotypes are associated with DNA damage. ► Concomitant presence of certain CYP2D6 and PON1 genotypes can increase DNA damage.

  19. Role of genetic polymorphisms of CYP1A1, CYP3A5, CYP2C9, CYP2D6, and PON1 in the modulation of DNA damage in workers occupationally exposed to organophosphate pesticides

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Satyender [Division of Biochemistry and Biotechnology, National Centre for Disease Control 22, Sham Nath Marg, Delhi-110054 (India); Kumar, Vivek [Environmental Biochemistry and Molecular Biology laboratory, Department of Biochemistry, University College of Medical Sciences and GTB Hospital, University of Delhi, Dilshad Garden, Delhi-110095 (India); Vashisht, Kapil; Singh, Priyanka [Division of Biochemistry and Biotechnology, National Centre for Disease Control 22, Sham Nath Marg, Delhi-110054 (India); Banerjee, Basu Dev, E-mail: banerjeebd@hotmail.com [Environmental Biochemistry and Molecular Biology laboratory, Department of Biochemistry, University College of Medical Sciences and GTB Hospital, University of Delhi, Dilshad Garden, Delhi-110095 (India); Rautela, Rajender Singh; Grover, Shyam Sunder; Rawat, Devendra Singh; Pasha, Syed Tazeen [Division of Biochemistry and Biotechnology, National Centre for Disease Control 22, Sham Nath Marg, Delhi-110054 (India); Jain, Sudhir Kumar [Centre for Epidemiology and Parasitic Diseases, National Centre for Disease Control 22, Sham Nath Marg, Delhi-110054 (India); Rai, Arvind [Division of Biochemistry and Biotechnology, National Centre for Disease Control 22, Sham Nath Marg, Delhi-110054 (India)

    2011-11-15

    Organophosphate pesticides (OPs) are primarily metabolized by several xenobiotic metabolizing enzymes (XMEs). Very few studies have explored genetic polymorphisms of XMEs and their association with DNA damage in pesticide-exposed workers. The present study was designed to determine the role of genetic polymorphisms of CYP1A1, CYP3A5, CYP2C9, CYP2D6, and PON1 in the modulation of DNA damage in workers occupationally exposed to OPs. We examined 284 subjects including 150 workers occupationally exposed to OPs and 134 normal healthy controls. The DNA damage was evaluated using the alkaline comet assay and genotyping was done using PCR-RFLP. The results revealed that the PONase activity toward paraoxonase and AChE activity was found significantly lowered in workers as compared to control subjects (p < 0.001). Workers showed significantly higher DNA damage compared to control subjects (14.37 {+-} 2.15 vs. 6.24 {+-} 1.37 tail% DNA, p < 0.001). Further, the workers with CYP2D6*3 PM and PON1 (QQ and MM) genotypes were found to have significantly higher DNA damage when compared to other genotypes (p < 0.05). In addition, significant increase in DNA damage was also observed in workers with concomitant presence of certain CYP2D6 and PON1 (Q192R and L55M) genotypes which need further extensive studies. In conclusion, the results indicate that the PON1 and CYP2D6 genotypes can modulate DNA damage elicited by some OPs possibly through gene-environment interactions. -- Highlights: Black-Right-Pointing-Pointer Role of CYP1A1, CYP3A5, CYP2C, CYP2D6 and PON1 genotypes on DNA damage. Black-Right-Pointing-Pointer Workers exposed to some OPs demonstrated increased DNA damage. Black-Right-Pointing-Pointer CYP2D6 *3 PM and PON1 (Q192R and L55M) genotypes are associated with DNA damage. Black-Right-Pointing-Pointer Concomitant presence of certain CYP2D6 and PON1 genotypes can increase DNA damage.

  20. Radiation damage and thermal shock response of carbon-fiber-reinforced materials to intense high-energy proton beams

    Directory of Open Access Journals (Sweden)

    N. Simos

    2016-11-01

    Full Text Available A comprehensive study on the effects of energetic protons on carbon-fiber composites and compounds under consideration for use as low-Z pion production targets in future high-power accelerators and low-impedance collimating elements for intercepting TeV-level protons at the Large Hadron Collider has been undertaken addressing two key areas, namely, thermal shock absorption and resistance to irradiation damage. Carbon-fiber composites of various fiber weaves have been widely used in aerospace industries due to their unique combination of high temperature stability, low density, and high strength. The performance of carbon-carbon composites and compounds under intense proton beams and long-term irradiation have been studied in a series of experiments and compared with the performance of graphite. The 24-GeV proton beam experiments confirmed the inherent ability of a 3D C/C fiber composite to withstand a thermal shock. A series of irradiation damage campaigns explored the response of different C/C structures as a function of the proton fluence and irradiating environment. Radiolytic oxidation resulting from the interaction of oxygen molecules, the result of beam-induced radiolysis encountered during some of the irradiation campaigns, with carbon atoms during irradiation with the presence of a water coolant emerged as a dominant contributor to the observed structural integrity loss at proton fluences ≥5×10^{20}  p/cm^{2}. The carbon-fiber composites were shown to exhibit significant anisotropy in their dimensional stability driven by the fiber weave and the microstructural behavior of the fiber and carbon matrix accompanied by the presence of manufacturing porosity and defects. Carbon-fiber-reinforced molybdenum-graphite compounds (MoGRCF selected for their impedance properties in the Large Hadron Collider beam collimation exhibited significant decrease in postirradiation load-displacement behavior even after low dose levels (∼5×10^{18}

  1. Radiation damage and thermal shock response of carbon-fiber-reinforced materials to intense high-energy proton beams

    Science.gov (United States)

    Simos, N.; Zhong, Z.; Ghose, S.; Kirk, H. G.; Trung, L.-P.; McDonald, K. T.; Kotsina, Z.; Nocera, P.; Assmann, R.; Redaelli, S.; Bertarelli, A.; Quaranta, E.; Rossi, A.; Zwaska, R.; Ammigan, K.; Hurh, P.; Mokhov, N.

    2016-11-01

    A comprehensive study on the effects of energetic protons on carbon-fiber composites and compounds under consideration for use as low-Z pion production targets in future high-power accelerators and low-impedance collimating elements for intercepting TeV-level protons at the Large Hadron Collider has been undertaken addressing two key areas, namely, thermal shock absorption and resistance to irradiation damage. Carbon-fiber composites of various fiber weaves have been widely used in aerospace industries due to their unique combination of high temperature stability, low density, and high strength. The performance of carbon-carbon composites and compounds under intense proton beams and long-term irradiation have been studied in a series of experiments and compared with the performance of graphite. The 24-GeV proton beam experiments confirmed the inherent ability of a 3D C/C fiber composite to withstand a thermal shock. A series of irradiation damage campaigns explored the response of different C/C structures as a function of the proton fluence and irradiating environment. Radiolytic oxidation resulting from the interaction of oxygen molecules, the result of beam-induced radiolysis encountered during some of the irradiation campaigns, with carbon atoms during irradiation with the presence of a water coolant emerged as a dominant contributor to the observed structural integrity loss at proton fluences ≥5 ×1020 p /cm2 . The carbon-fiber composites were shown to exhibit significant anisotropy in their dimensional stability driven by the fiber weave and the microstructural behavior of the fiber and carbon matrix accompanied by the presence of manufacturing porosity and defects. Carbon-fiber-reinforced molybdenum-graphite compounds (MoGRCF) selected for their impedance properties in the Large Hadron Collider beam collimation exhibited significant decrease in postirradiation load-displacement behavior even after low dose levels (˜5 ×1018 p cm-2 ). In addition, the

  2. Diagnostics of the dynamics of material damage by thermal shocks with the intensity possible in the ITER divertor

    Science.gov (United States)

    Vyacheslavov, L. N.; Arakcheev, A. S.; Bataev, I. A.; Burdakov, A. V.; Kandaurov, I. V.; Kasatov, A. A.; Kurkuchekov, V. V.; Popov, V. A.; Shoshin, A. A.; Skovorodin, D. I.; Trunev, Yu A.; Vasilyev, A. A.

    2018-03-01

    A novel BETA test facility (Beam of Electrons for materials Test Applications) was developed at the Budker Institute to study the erosion of materials directly during the impact of intense thermal shocks. A powerful (up to 7 MW) long pulse (100–300 μs) electron beam is applied for experimental simulation of fast transient heat loads with the intensity probable in the ITER divertor. The heat flux parameter on a target can be widely varied (FHF = 10–300 MW m‑2 s0.5) from a value significantly below the melting threshold to a value much higher, within the area of about 1 cm2. The use of an electron beam to simulate the thermal impact on the material surface makes it possible to employ a variety of optical diagnostics for in situ observations of the dynamics of surface erosion processes during intense thermal shocks. These distinctive features make BETA a promising tool in the research of material surface erosion mechanisms and for experimental verification of various analytical and numerical models associated with these mechanisms. The first results obtained with this facility include fast (10 μs exposure) imaging of the heated target in the near-infrared range and in the reflected light of 532 nm continuous wave (CW) laser, visualization of ejected tungsten particles using fast ICCD and CCD cameras with the minimal exposure of 2 μs and 7 μs respectively. The dynamics of dust particles ejected from the heated surface is investigated using a multichannel recording of the light of 532 nm CW-laser scattered on the dust particles. The present paper describes the first results of use of two new in situ methods: continuous recording of light scattered from the tungsten surface and three-dimensional tracking of tungsten particles using three viewing angles. The first method makes it possible to observe the dynamics of development of roughness and cracking of the polished tungsten surface, which manifest themselves as two successive processes separated by a large

  3. EFFECT OF DISINFECTANTS BASED ON POTASSIUM PERSULFATE, HYDROGEN PEROXIDE, GLUTARALDEHYDE AND QUATERNARY AMMONIUM COMPOUNDS ON THE GENETIC MATERIAL OF THE PATHOGEN BACTERIA SPECIFIC TO MEAT PROCESSING INDUSTRY

    Directory of Open Access Journals (Sweden)

    V. N. Afonyushkin

    2016-01-01

    Full Text Available Abstract The changes in bacterial genetic material under the action of different biocidal products have been investigated. It was confirmed by PCR and genetic engineering that biocidal product Ecocid was able to remove both chromosomal and plasmid DNA, either isolated or contained within the bacterial cells. Using a disinfectant that destroys DNA on the surfaces of meat production equipment is a promising measure to prevent horizontal transfer of unwanted genetic material, such as bacterial genes associated with the resistance to antibiotics, or genes of toxin production.

  4. Simulations of material damage to divertor and first wall armour under ITER transient loads by modelling and experiments

    International Nuclear Information System (INIS)

    Bazylev, B.

    2008-01-01

    Operation of ITER at high fusion gain is assumed to be the H-mode. A characteristic feature of this regime is the transient energy release (TE) from the confined plasma onto plasma facing components (PFCs), which can play a determining role in lifetime of these components. The expected fluxes on the ITER PFCs during transients are: Type I ELM Q = 0.5 - 4 MJ/m 2 in timescales t = 0.3 - 0.6 ms, and thermal quench Q = 2 - 13 MJ/m 2 with t = 1 - 3 ms. CFC and tungsten macrobrush armour are foreseen as PFCs for ITER divertor and Be - as FW armour. During the intense TE in ITER the evaporation (CFC, W, Be) and surface melting and melt splashing (W and Be) are seen as the main mechanisms of PFC erosion. A noticeable erosion of CFC PAN fibres and rather intense crack formation for the W targets were observed in plasma gun experiments at rather small heat loads at which the melt damage to W armour is not substantial. The expected erosion of the ITER PFCs TE can be properly estimated by numerical simulations validated against erosion experiments at the plasma gun facilities QSPA-T, MK- 200UG and QSPA-Kh50. Within collaboration between EU fusion programme and Russian Federation, CFC and W macrobrush targets manufactured in EU were exposed to multiple ITER TE-like loads with Q = 0.5 - 2.2 MJ/m 2 and t = 0 .5 ms at the QSPA-T. The measured erosion was used to validate the modelling codes developed in FZK (PEGASUS, MEMOS, and others), which are then applied to model the erosion of the divertor and main chamber ITER PFCs under expected transient loads in ITER. Numerical simulations performed for the expected ITER-like loads predicted: a significant erosion of the CFC target for Q > 0.5 MJ/m 2 was caused by the inhomogeneous structure of the CFC; the W macrobrush structure is effective in preventing gross melt layer displacement. Optimization of macrobrush geometry to minimize melt splashing is done. Different mechanisms of melt splashing are compared with the results obtained in

  5. Superelastic Ball Bearings: Materials and Design to Avoid Mounting and Dismounting Brinell Damage in an Inaccessible Press-Fit Application-. I ; Design Approach

    Science.gov (United States)

    Dellacorte, Christopher; Howard, S. Adam

    2015-01-01

    Ball bearings require proper fit and installation into machinery structures (onto shafts and into bearing housings) to ensure optimal performance. For some applications, both the inner and outer race must be mounted with an interference fit and care must be taken during assembly and disassembly to avoid placing heavy static loads between the balls and races otherwise Brinell dent type damage can occur. In this paper, a highly dent resistant superelastic alloy, 60NiTi, is considered for rolling element bearing applications that encounter excessive static axial loading during assembly or disassembly. A small (R8) ball bearing is designed for an application in which access to the bearing races to apply disassembly tools is precluded. First Principles analyses show that by careful selection of materials, raceway curvature and land geometry, a bearing can be designed that allows blind assembly and disassembly without incurring raceway damage due to ball denting. Though such blind assembly applications are uncommon, the availability of bearings with unusually high static load capability may enable more such applications with additional benefits, especially for miniature bearings.

  6. The comparison of two continuum damage mechanics-based material models for formability prediction of AA6082 under hot stamping conditions

    Science.gov (United States)

    Shao, Z.; Li, N.; Lin, J.

    2017-09-01

    The hot stamping and cold die quenching process has experienced tremendous development in order to obtain shapes of structural components with great complexity in automotive applications. Prediction of the formability of a metal sheet is significant for practical applications of forming components in the automotive industry. Since microstructural evolution in an alloy at elevated temperature has a large effect on formability, continuum damage mechanics (CDM)-based material models can be used to characterise the behaviour of metals when a forming process is conducted at elevated temperatures. In this paper, two sets of unified multi-axial constitutive equations based on material’s stress states and strain states, respectively, were calibrated and used to effectively predict the thermo-mechanical response and forming limits of alloys under complex hot stamping conditions. In order to determine and calibrate the two material models, formability tests of AA6082 using a developed novel biaxial testing system were conducted at various temperatures and strain rates under hot stamping conditions. The determined unified constitutive equations from experimental data are presented in this paper. It is found that both of the stress-state based and strain-state based material models can predict the formability of AA6082 under hot stamping conditions.

  7. Materials

    CSIR Research Space (South Africa)

    Van Wyk, Llewellyn V

    2009-02-01

    Full Text Available community. The construction industry is a significantly consumer of materials, using 50 per cent of all products produced globally. Building materials is any material which is used for a construction purpose. Many of these materials are sources from natural...

  8. Session V: Management of Radioactive Waste and Damaged Fuel. Session V-A: Generation and Management of Materials and Waste

    International Nuclear Information System (INIS)

    Blommaert, W.; Cheng Hui

    2013-01-01

    Mitigation of the Chernobyl accident consequences stressed the attention on the huge volumes and the variety of wastes resulting from the accident (almost all long- lived and alfa containing radioactive waste). The accident and the mitigation of the consequences clearly demonstrated the level of unpreparedness for such accident, the absence of experience in the management of huge amounts of contaminated materials, as well as the lack of storage /disposal capacity. This resulted in a ''not organized storage for not organized waste''. Hence, large amounts of contaminated materials are being stored under conditions that do not fully comply with present international safety requirements. During mitigation and clean-up operations after the Chernobyl accident, disposal facilities were constructed. Some of them are located in areas with high water table and hence (potentially) result in contamination of groundwater. For this reason some of them will require re-disposal, requiring itself a comprehensive safety assessment. On the other hand, the Chernobyl accident resulted, during the early phase of the accident, in the creation of a special governmental ''brainstorming'' commission on the decision making process, with a clear allocation of responsibilities and with full power. Later on, considered options for the management of different ''Chernobyl'' waste types (solid, liquid, fuel,) were provided in the National Policy and Strategy. Attention was drawn to the fact that pre-operational work is a time and cost consuming process. Up to now there is no decision on geological disposal. The development of facilities on the ''Vector site'' in the exclusion zone of Chernobyl is going on. The Vector operation covers retrieval operation of radioactive waste, characterization activities, processing activities, transport and storage/disposal of the radioactive waste in the exclusion zone. National legislation does not take into account the peculiarity of the ''Chernobyl'' waste and

  9. Dictionary materials engineering, materials testing

    International Nuclear Information System (INIS)

    1994-01-01

    This dictionary contains about 9,500 entries in each part of the following fields: 1) Materials using and selection; 2) Mechanical engineering materials -Metallic materials - Non-metallic inorganic materials - Plastics - Composites -Materials damage and protection; 3) Electrical and electronics materials -Conductor materials - Semiconductors - magnetic materials - Dielectric materials - non-conducting materials; 4) Materials testing - Mechanical methods - Analytical methods - Structure investigation - Complex methods - Measurement of physical properties - Non-destructive testing. (orig.) [de

  10. 3D cellular automata finite element (CAFE) modelling and experimental observation of damage in quasi-brittle nuclear materials: Indentation of a SiC-SiC-fibre ceramic matrix composite

    International Nuclear Information System (INIS)

    Saucedo Mora, Luis; Mostafavi, Mahmoud; Marrow, T. James; Khoshkhou, Danial; Connolly, Brian; Reinhard, Christina; Atwood, Robert; Zhao, Shuang

    2015-01-01

    Cellular automata integrated with finite elements (CAFE) have been used to develop a method to account for the effect of microstructure on quasi-brittle damage development. The microstructure is simulated explicitly by subdividing a finite element into smaller cells. A heterogeneous structure is created from key cells (seeds) using defined characteristics; the influence of the initial finite element mesh is effectively removed during the development of the microstructure. Graded microstructures, textures, particle anisotropy and multiple phases can be readily simulated, such as those in composites and porous materials. A mesh-free framework has been developed to compute the damage development through the microstructure, using cellular automata. With this method, we can study the development of discontinuous cracking and damage coalescence, and its sensitivity to microstructure. Experiments have been carried out to observe the three-dimensional development of damage, using high-resolution synchrotron X-ray computed tomography and digital volume correlation to observe Hertzian indentation of a SiC-SiC fibre composite, quantifying damage by measurement of the displacement fields within the material. The results demonstrate the applicability of the modelling strategy to damage development, and show how model input data may be obtained from small specimen tests, which could be performed at elevated temperatures with irradiated materials. (authors)

  11. Multiobjective optimization design of green building envelope material using a non-dominated sorting genetic algorithm

    International Nuclear Information System (INIS)

    Yang, Ming-Der; Lin, Min-Der; Lin, Yu-Hao; Tsai, Kang-Ting

    2017-01-01

    Highlights: • An effective envelope energy performance model (BEM) was developed. • We integrated NSGA-II with the BEM to optimize the green building envelope. • A tradeoff plan of green building design for three conflict objectives was obtained. • The optimal envelope design efficiently reduced the construction cost of green building. - Abstract: To realize the goal of environmental sustainability, improving energy efficiency in buildings is a major priority worldwide. However, the practical design of green building envelopes for energy conservation is a highly complex optimization problem, and architects must make multiobjective decisions. In practice, methods such as multicriteria analyses that entail capitalizing on possibly many (but in nearly any case limited) alternatives are commonly employed. This study investigated the feasibility of applying a multiobjective optimal model on building envelope design (MOPBEM), which involved integrating a building envelope energy performance model with a multiobjective optimizer. The MOPBEM was established to provide a reference for green designs. A nondominated sorting genetic algorithm-II (NSGA-II) was used to achieve a tradeoff design set between three conflicting objectives, namely minimizing the envelope construction cost (ENVCOST), minimizing the envelope energy performance (ENVLOAD), and maximizing the window opening rate (WOPR). A real office building case was designed using the MOPBEM to identify the potential strengths and weaknesses of the proposed MOPBEM. The results showed that a high ENVCOST was expended in simultaneously satisfying the low ENVLOAD and high WOPR. Various designs exhibited obvious cost reductions compared with the original architects' manual design, demonstrating the practicability of the MOPBEM.

  12. Electron damage in organic crystals

    International Nuclear Information System (INIS)

    Howitt, D.G.; Thomas, G.

    1977-01-01

    The effects of radiation damage in three crystalline organic materials (l-valine, cytosine, copper phthalocyanine) have been investigated by electron microscopy. The degradation of these materials has been found to be consistent with a gradual collapse of their crystal structures brought about by ionization damage to the comprising molecules. It is inferred that the crystallinity of these materials is destroyed by ionizing radiation because the damaged molecules cannot be incorporated into the framework of their original structures. (author)

  13. Activity of the protector chlorophyllin or promoter of the genetic damage induced by the 1,2 dimethyl hydrazine; Actividad de la clorofilina protectora o promotora del dano genetico inducido por la 1,2 dimetil hidrazina

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero M, M.G

    2004-07-01

    The chlorophyllin (CHLN) it is a porphyrin of soluble nutritious grade in water, derived of the chlorophyll that includes in their structure a copper atom. It has been reported that this pigment can act as anti mutagen, reducing the damage to the DNA caused by physical or chemical agents of direct or indirect action. Their anti carcinogen action has also been studied during the initiation phase induced for carcinogen as the aflatoxins and heterocyclic amines. In contrast the reports have increased on a probable promoter activity of the CHLN on the induced genetic damage. This effect was seen for the first time before the damage induced by alkylating agents in Salmonella. Recently it has been observed with the damage induced by gamma radiation, ENU and CrO{sub 3} in somatic cells of the wing of Drosophila and in the induction of tumors for 1,2-dimethylhydrazine (DMH) in mice. Presently study is evaluated the protective effect or promoter of the CHLN before the genetic damage induced by 1,2-dimethylhydrazine, by means of the bioassay mutation and somatic recombination (SMART) in the wing of Drosophila melanogaster. Its were pretreated with CHLN or SAC to transheterocygotes larvas for two locus of the chromosome three mwh+/+flr{sup 3}; later on they are retarded the chronic treatment with DMH 0, 1, 2 and 3 days. It was measured the toxicity and the speed of development of the treated individuals. The wings of those adults that emerged were analyzed to register the number and the size of stains. The results indicated: differences in the viability of the individuals of the groups SAC + DMH vs CHLN + DMH only in the treated immediately after the pretreatment (DRT-0) that the CHLN doesn't modify the rate of the treated individuals development. The results of somatic mutation indicated that the CHLN has a protective effect only immediately after the pretreatment (DRT-0) however in DRT-1, 2 and 3 showed a promoter effect of genetic damage. (Author)

  14. Materialism.

    Science.gov (United States)

    Melnyk, Andrew

    2012-05-01

    Materialism is nearly universally assumed by cognitive scientists. Intuitively, materialism says that a person's mental states are nothing over and above his or her material states, while dualism denies this. Philosophers have introduced concepts (e.g., realization and supervenience) to assist in formulating the theses of materialism and dualism with more precision, and distinguished among importantly different versions of each view (e.g., eliminative materialism, substance dualism, and emergentism). They have also clarified the logic of arguments that use empirical findings to support materialism. Finally, they have devised various objections to materialism, objections that therefore serve also as arguments for dualism. These objections typically center around two features of mental states that materialism has had trouble in accommodating. The first feature is intentionality, the property of representing, or being about, objects, properties, and states of affairs external to the mental states. The second feature is phenomenal consciousness, the property possessed by many mental states of there being something it is like for the subject of the mental state to be in that mental state. WIREs Cogn Sci 2012, 3:281-292. doi: 10.1002/wcs.1174 For further resources related to this article, please visit the WIREs website. Copyright © 2012 John Wiley & Sons, Ltd.

  15. Genetics of the Steller's Sea Cow (Hydrodamalis gigas): A Study of Ancient Bone Material

    Science.gov (United States)

    Crerar, Lorelei D.

    Georg Wilhelm Steller was born 100 years before Darwin in 1709 and he was part of a vast exploration fifty years before Lewis and Clark explored America. Steller was important to the study of marine mammals because he was the only naturalist to see and describe the great northern sea cow ( Hydrodamalis gigas). Knowledge of an extinct population can be used to aid the conservation of a current population. Extraction of DNA from this extinct animal was performed in order to determine the population structure of the Steller's sea cow. A test was also developed that can definitively state whether or not a random bone sample came from H. gigas. This test could be used by the Fish and Wildlife Service (FWS) and the National Oceanic and Atmospheric Administration (NOAA) to examine material distributed in the North Pacific to determine whether samples are legally traded extinct Steller's sea cow or illegally traded extant marine mammal species protected under the Marine Mammal Protection Act (MMPA).

  16. Generating information-rich high-throughput experimental materials genomes using functional clustering via multitree genetic programming and information theory.

    Science.gov (United States)

    Suram, Santosh K; Haber, Joel A; Jin, Jian; Gregoire, John M

    2015-04-13

    High-throughput experimental methodologies are capable of synthesizing, screening and characterizing vast arrays of combinatorial material libraries at a very rapid rate. These methodologies strategically employ tiered screening wherein the number of compositions screened decreases as the complexity, and very often the scientific information obtained from a screening experiment, increases. The algorithm used for down-selection of samples from higher throughput screening experiment to a lower throughput screening experiment is vital in achieving information-rich experimental materials genomes. The fundamental science of material discovery lies in the establishment of composition-structure-property relationships, motivating the development of advanced down-selection algorithms which consider the information value of the selected compositions, as opposed to simply selecting the best performing compositions from a high throughput experiment. Identification of property fields (composition regions with distinct composition-property relationships) in high throughput data enables down-selection algorithms to employ advanced selection strategies, such as the selection of representative compositions from each field or selection of compositions that span the composition space of the highest performing field. Such strategies would greatly enhance the generation of data-driven discoveries. We introduce an informatics-based clustering of composition-property functional relationships using a combination of information theory and multitree genetic programming concepts for identification of property fields in a composition library. We demonstrate our approach using a complex synthetic composition-property map for a 5 at. % step ternary library consisting of four distinct property fields and finally explore the application of this methodology for capturing relationships between composition and catalytic activity for the oxygen evolution reaction for 5429 catalyst compositions in a

  17. Synthesis and stabilization of oxide-based colloidal suspensions in organic media: application in the preparation of hybrids organic-inorganic materials for very high laser damage threshold coatings

    International Nuclear Information System (INIS)

    Marchet, N.

    2008-02-01

    Multilayer coatings are widely used in optic and particular in the field of high power laser on the components of laser chains. The development of a highly reflective coating with a laser damage resistance requires the fine-tuning of a multilayer stack constituted by a succession alternated by materials with low and high refractive index. In order to limit the number of layers in the stack, refractive indexes must be optimized. To do it, an original approach consists in synthesizing new organic-inorganic hybrid materials satisfying the criteria of laser damage resistance and optimized refractive index. These hybrid materials are constituted by nano-particles of metal oxides synthesized by sol-gel process and dispersed in an organic polymer with high laser damage threshold. Nevertheless, this composite system requires returning both compatible phases between them by chemical grafting of alc-oxy-silanes or carboxylic acids. We showed that it was so possible to disperse in a homogeneous way these functionalized nano-particles in non-polar, aprotic solvent containing solubilized organic polymers, to obtain time-stable nano-composite solutions. From these organic-inorganic hybrid solutions, thin films with optical quality and high laser damage threshold were obtained. These promising results have permitted to realize highly reflective stacks, constituted by 7 pairs with optical properties in agreement with the theoretical models and high laser damage threshold. (author)

  18. Superelastic Ball Bearings: Materials and Design to Avoid Mounting and Dismounting Brinell Damage in an Inaccessible Press-fit Application-. II; Detailed Analysis

    Science.gov (United States)

    Howard, S. Adam; Dellacorte, Christopher

    2015-01-01

    Rolling element bearings utilized in precision rotating machines require proper alignment, preload, and interference fits to ensure overall optimum performance. Hence, careful attention must be given to bearing installation and disassembly procedures to ensure the above conditions are met. Usually, machines are designed in such a way that bearings can be pressed into housings or onto shafts through the races without loading the rolling elements. However, in some instances, either due to limited size or access, a bearing must be installed or removed in such a way that the load path travels through the rolling elements. This can cause high contact stresses between the rolling elements and the races and introduces the potential for Brinell denting of the races. This paper is a companion to the Part I paper by the authors that discusses material selection and the general design philosophy for the bearing. Here, a more in-depth treatment is given to the design of a dent-resistant bearing utilizing a superelastic alloy, 60NiTi, for the races. A common bearing analysis tool based on rigid body dynamics is used in combination with finite element simulations to design the superelastic bearing. The primary design constraints are prevention of denting and avoiding the balls riding over the edge of the race groove during a blind disassembly process where the load passes through the rolling elements. Through an iterative process, the resulting bearing geometry is tailored to improve axial static load capability compared to a deep-groove ball bearing of the same size. The results suggest that careful selection of materials and bearing geometry can enable blind disassembly without damage to the raceways, which is necessary in the current application (a compressor in the International Space Station Environmental Control and Life Support System), and results in potential design flexibility for other applications, especially small machines with miniature bearings.

  19. Institute of Genetics and of Toxicology of Fissile Materials. Progress report on research and development work in 1992

    International Nuclear Information System (INIS)

    1993-03-01

    In the year under report, the institute's scope of investigations comprised the seven topics surveyed in the following together with the most recent research results obtained. These were genetic repair and genetic regulation mechanisms, biologic carcinogenesis, molecular genetics of eukaryotic genes, genetic mouse models of human disorders, toxicology of radioactive and non-radioactive heavy metals as well as environmental toxicology at the molecular and cellular levels. (orig./MG) [de

  20. Action of the chlorophyllin before genetic damage induced by gamma radiation in germinal cells of Drosophila; Accion de la clorofilina ante el dano genetico inducido por radiacion gamma en celulas germinales de Drosophila

    Energy Technology Data Exchange (ETDEWEB)

    Moreno B, R

    2004-07-01

    The chlorophyllin (CHLN) is a porphyrin of nutritious grade and soluble in water, derived of the chlorophyll. It has been reported that this pigment is a good anti mutagen since it reduces the damage to the DNA caused by physical or chemical agents of direct or indirect action. Their anti carcinogenic action has also been demonstrated when it is administered itself during the induced post-initiation phase by aflatoxins and heterocyclic amines. However in the last decade it has been reported that it also has promoter activity against the genetic damage induced by diverse agents like the alkyl ants of direct and indirect action, the gamma radiation and some heterocyclic amines. This effect has been observed in testing systems like Salmonella, Drosophila, rainbow trout and rodents. In the mouse spermatogonia it has been reported that it reduces the damage to the DNA but with the test of lethal dominant in Drosophila increment the damage induced by gamma radiation. The present study consisted on evaluating the effect of the CHLN in the line germinal masculine of Drosophila by means of the lethal recessive test bound to the sex (LRLS) with the stump Muller 5 and a litters system. Its were pretreated wild males with CHLN and 24 h later were irradiated with 0, 10, 20 and 40 Gy of gamma radiation immediately later were crossed with virgin females of the stump Basc and at 72 h the male was transferred to a cultivation media with three new virgin females, this process repeated three times until completing 3 litters. The F1 it was crossed among itself and in the F2 it was analysed the presence or absence of lethals. The results indicated that the CHLN per se incremented the basal frequency of damage due to the pigment can act as an agent that is inserted to the ADN causing pre mutagenic leisure. Nevertheless with the groups treated with the different doses of gamma radiation the CHLN does not present any protector action, neither promoter except in the litter I of the group

  1. PCR-free quantitative detection of genetically modified organism from raw materials. An electrochemiluminescence-based bio bar code method.

    Science.gov (United States)

    Zhu, Debin; Tang, Yabing; Xing, Da; Chen, Wei R

    2008-05-15

    A bio bar code assay based on oligonucleotide-modified gold nanoparticles (Au-NPs) provides a PCR-free method for quantitative detection of nucleic acid targets. However, the current bio bar code assay requires lengthy experimental procedures including the preparation and release of bar code DNA probes from the target-nanoparticle complex and immobilization and hybridization of the probes for quantification. Herein, we report a novel PCR-free electrochemiluminescence (ECL)-based bio bar code assay for the quantitative detection of genetically modified organism (GMO) from raw materials. It consists of tris-(2,2'-bipyridyl) ruthenium (TBR)-labeled bar code DNA, nucleic acid hybridization using Au-NPs and biotin-labeled probes, and selective capture of the hybridization complex by streptavidin-coated paramagnetic beads. The detection of target DNA is realized by direct measurement of ECL emission of TBR. It can quantitatively detect target nucleic acids with high speed and sensitivity. This method can be used to quantitatively detect GMO fragments from real GMO products.

  2. [Comparative cytological and molecular analysis of introgressive common wheat lines containing genetic material of Triticum timopheevii Zhur].

    Science.gov (United States)

    Gordeeva, E I; Leonova, I N; Kalinina, N P; Salina, E A; Budashkina, E b

    2009-12-01

    A total of 40 introgressive lines of common wheat (2n = 42) Triticum aestivum L x T. timopheevii Zhuk., resistant to brown rust and partly to powdery mildew, were examined. Based on cytological analysis of meiosis in pollen mother cells (PMC), hybrid lines were subdivided into two groups characterized by either stable or unstable meiosis. In cytologically stable lines, chromosome configuration at the MI stage of meiosis was mostly bivalent (21II) with small proportion of defect cells (almost 10%), which at most contained two univalents (20II + + 21). Cytologically unstable group was comprised of the lines, containing high proportions of cells with abnormal chromosome pairing in meiotic PMC, as well as the cells with multivalents, and the lines containing aneuploid plants. Localization of the T. timopheevii fragments performed with the use of SSR markers showed that the lines with unstable meiosis were characterized by higher numbers of introgressions compared to stable lines. The influence of certain chromosomes of T. timopheevii on chromosome pairing stability was also demonstrated. In cytologically unstable lines, the increased frequency of 2A substitutions along with the high frequency of introgression of T. timopheevii genetic material into chromosome 7A was observed. Multivalents were scored in all cases of introgression in chromosome 7A. It was suggested that the reason for the genome instability in hybrid forms lied in insufficient compensating ability of certain T. timopheevii chromosomes and/or their parts, involved into recombination processes.

  3. The association between genetic damage in peripheral blood lymphocytes and polymorphisms of three glutathione S-transferases in Chinese workers exposed to 1,3-butadiene.

    Science.gov (United States)

    Cheng, Xuemei; Zhang, Tianliang; Zhao, Jing; Zhou, Jingyang; Shao, Hua; Zhou, Zhonghua; Kong, Fanling; Feng, Nannan; Sun, Yuan; Shan, Baode; Xia, Zhaolin

    2013-01-20

    1,3-Butadiene (BD) has been classified as a human carcinogen, group I; however, the relationship between polymorphisms of glutathione S-transferases that metabolize BD and chromosomal damage is not clear. The present study used sister chromatid exchange (SCE) and cytokinesis-block micronucleus (CBMN) assays to detect chromosomal damage in peripheral lymphocytes of 44 BD-exposed workers and 39 non-exposed healthy controls. PCR and PCR-RFLP were employed to detect three known glutathione S-transferase polymorphisms GSTT1, GSTM1, and GSTP1 (Ile105Val). The data demonstrated that the micronucleus (CBMN) frequency in BD-exposed workers was significantly higher than that in controls (frequency ratio (FR)=1.48, 95% CI: 1.14-1.91, P0.05). Among exposed workers, chromosomal damage was related to BD exposure levels (FR=1.35, 95% CI: 1.02-1.80, P0.05). Our results suggested that higher levels of BD exposure in the workplace resulted in increased chromosomal damage, and that polymorphisms in GSTT1 and GSTM1 genes might modulate the genotoxic effects of BD exposure. Furthermore, the GSTT1 and GSTM1 polymorphisms exhibited an additive effect. Finally, urinary DHBMA was found to provide a biomarker that correlated with airborne BD levels. Copyright © 2012 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    1999-02-01

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

  5. A Juridical Insight of Brave New World: The Eugenics Found on the Selection Criteria of Genetic Material for the Assisted Human Reproduction

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo de Oliveira Alban

    2016-06-01

    Full Text Available Following the teachings of the “Law in the Literature” movement, as well as the method of the Phemenological Hermeneutics, the present essay intends to discuss the eugenics content present in the abstract criteria for donating genetic material in Brazil. In order to present this problem clearly for the reader, the novel Brave New World, from Aldous Huxley, will be used as an example. Opportunely, it will deal with the recent situation regarding the investigation of the London Sperm Bank donators’ politics, in which important debates related to the genetic selection aiming for avoiding congenital diseases appear.

  6. The relationship between biomarkers of oxidative DNA damage, polycyclic aromatic hydrocarbon DNA adducts, antioxidant status and genetic susceptibility following exposure to environmental air pollution in humans

    Czech Academy of Sciences Publication Activity Database

    Shing, R.; Šrám, Radim; Binková, Blanka; Kalina, I.; Popov, T. A.; Georgieva, T.; Garte, S.; Taioli, E.; Farmer, P. B.

    2007-01-01

    Roč. 620, - (2007), s. 83-92 ISSN 0027-5107 Grant - others:EU(GB) 2000-00091; EU(GB) G0100873 Institutional research plan: CEZ:AV0Z50390512 Source of funding: R - rámcový projekt EK ; R - rámcový projekt EK Keywords : air pollution * PAHs * oxidative DNA damage Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 4.159, year: 2007

  7. Association between Genetic Polymorphisms of DNA Repair Genes and Chromosomal Damage for 1,3-Butadiene-Exposed Workers in a Matched Study in China.

    Science.gov (United States)

    Xiang, Menglong; Sun, Lei; Dong, Xiaomei; Yang, Huan; Liu, Wen-bin; Zhou, Niya; Han, Xue; Zhou, Ziyuan; Cui, Zhihong; Liu, Jing-yi; Cao, Jia; Ao, Lin

    2015-01-01

    The aim of the study was to examine the association between polymorphisms of DNA repair genes and chromosomal damage of 1,3-butadiene- (BD-) exposed workers. The study was conducted in 45 pairs of occupationally exposed workers in a BD product workshop and matched control workers in an administrative office and a circulatory water workshop in China. Newly developed biomarkers (micronuclei, MNi; nucleoplasmic bridges, NPBs; nuclear buds, NBUDs) in the cytokinesis-blocked micronucleus (CBMN) cytome assay were adopted to detect chromosomal damage. PCR and PCR-restriction fragment length polymorphism (RFLP) are adopted to analyze polymorphisms of DNA repair genes, such as X-ray repair cross-complementing Group 1 (XRCC1), O6-methylguanine-DNA methyltransferase (MGMT), poly (adenosine diphosphate-ribose) polymerases (ADPRT), and apurinic/apyrimidinic endonucleases (APE1). The BD-exposed workers exhibited increased frequencies of MNi and NPBs when compared to subjects in the control group. The results also show that the BD-exposed workers carrying XRCC1 diplotypes TCGA-CCGG (4.25 ± 2.06 ‰) (FR = 2.10, 95% CI: 1.03-4.28) and TCGG-TCGA (5.80 ± 3.56 ‰) (FR = 2.75, 95% CI: 0.76-2.65) had statistically higher NBUD frequencies than those who carried diplotype TCGG-TCGG (1.89 ± 1.27 ‰). Our study suggests that polymorphisms of XRCC1 gene may influence chromosomal damage in BD-exposed workers.

  8. Development of Certified Matrix-Based Reference Material as a Calibrator for Genetically Modified Rice G6H1 Analysis.

    Science.gov (United States)

    Yang, Yu; Li, Liang; Yang, Hui; Li, Xiaying; Zhang, Xiujie; Xu, Junfeng; Zhang, Dabing; Jin, Wujun; Yang, Litao

    2018-04-03

    The accurate monitoring and quantification of genetically modified organisms (GMOs) are key points for the implementation of labeling regulations, and a certified reference material (CRM) acts as the scaleplate for quantifying the GM contents of foods/feeds and evaluating a GMO analytical method or equipment. Herein we developed a series of CRMs for transgenic rice event G6H1, which possesses insect-resistant and herbicide-tolerant traits. Three G6H1 CRMs were produced by mixing seed powders obtained from homozygous G6H1 and its recipient cultivar Xiushui 110 at mass ratios of 49.825%, 9.967%, and 4.986%. The between-bottle homogeneity and within-bottle homogeneity were thoroughly evaluated with consistent results. The potential DNA degradation in transportation and shelf life were evaluated with an expiration period of at least 12 months. The property values of three CRMs (G6H1 a , G6H1 b , G6H1 c ) were given as (49.825 ± 0.448) g/kg, (9.967 ± 1.757) g/kg, and (4.986 ± 1.274 g/kg based on mass fraction ratio, respectively. Furthermore, the three CRMs were characterized with values of (5.01 ± 0.08)%, (1.06 ± 0.22)%, and (0.53 ± 0.11)% based on the copy number ratio using the droplet digital PCR method. All results confirmed that the produced G6H1 matrix-based CRMs are of high quality with precise characterization values and can be used as calibrators in GM rice G6H1 inspection and monitoring and in evaluating new analytical methods or devices targeting the G6H1 event.

  9. Continuous damage mechanics

    International Nuclear Information System (INIS)

    Chaboche, J.L.

    1981-01-01

    The classical structural life predictions are based on stabilized stress-strain analysis and some parametric relations with the number of cycles to failure. During the last ten years a different approach, initiated by the works of Kachanov and Rabotnov for creep rupture, has been developed by different laboratories. This continuous Damage Mechanics, treating the damaged material as a macroscopically homogeneous one, leads to the possibility of globally modelling the nucleation and the propagation of microdefects including their effect on the stress-strain behaviour. This paper presents the general theory and several applications to a turbine blade refractory alloy. It includes the description of sequence effects and creep-fatigue interaction. The generalization for three-dimensional conditions, where anisotropic damage effects are possible, is discussed and some new proposals are given for the determination of simple anisotropic damage equations. (orig.)

  10. Arthropod Genetics.

    Science.gov (United States)

    Zumwalde, Sharon

    2000-01-01

    Introduces an activity on arthropod genetics that involves phenotype and genotype identification of the creature and the construction process. Includes a list of required materials and directions to build a model arthropod. (YDS)

  11. Development of Genomic DNA Reference Materials for Genetic Testing of Disorders Common in People of Ashkenazi Jewish Descent

    OpenAIRE

    Kalman, Lisa; Wilson, Jean Amos; Buller, Arlene; Dixon, John; Edelmann, Lisa; Geller, Louis; Highsmith, William Edward; Holtegaard, Leonard; Kornreich, Ruth; Rohlfs, Elizabeth M.; Payeur, Toby L.; Sellers, Tina; Toji, Lorraine; Muralidharan, Kasinathan

    2009-01-01

    Many recessive genetic disorders are found at a higher incidence in people of Ashkenazi Jewish (AJ) descent than in the general population. The American College of Medical Genetics and the American College of Obstetricians and Gynecologists have recommended that individuals of AJ descent undergo carrier screening for Tay Sachs disease, Canavan disease, familial dysautonomia, mucolipidosis IV, Niemann-Pick disease type A, Fanconi anemia type C, Bloom syndrome, and Gaucher disease. Although the...

  12. Studies on mutagen-sensitive strains of Drosophila melanogaster. IX. Modification of genetic damage induced by X-irradiation of spermatozoa in N2, air or O2 by 4 autosomal repair-deficient mutants

    International Nuclear Information System (INIS)

    Ferro, W.

    1986-01-01

    The influence of defects in DNA repair on the recovery of X-ray-induced genetic damage in spermatozoa of Drosophila melanogaster was studied. Basc males were irradiated in N 2 , air or O 2 and mated to females of 4 repair-deficient mutant types. The responses in the different crosses with repair-deficient females were compared to those with repair-proficient mei + females (maternal effects). The main findings are the following: (1) with excision repair-deficient females the frequencies of spontaneous recessive lethals tend to be higher than with mei + females; (2) with excision repair-deficient females the frequencies of recessive lethals induced in N 2 and air and often in O 2 are higher than with mei + females; (3) with post-replication repair-deficient mutants a maternal effect is found for X-ray-induced translocations. The data are discussed and explained. (Auth.)

  13. Genetic effects from internally deposited radionuclides

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    It was learned in the late 1920's that ionizing radiation could produce genetic effects such as gene mutations and chromosome aberrations. However, at least until 1945, the focus on interest in radiation protection was primarily on somatic effects manifested in the individual exposed. Studies of the genetic effects of radiation using drosophila, however, refocused attention on effects transmitted to the exposed individuals offspring and concern over fallout in the 1950's resulted in efforts to estimate the genetic effects from exposure of human populations to internally deposited radionuclides. No human populations have been identified with burdens of internally deposited radioactive materials which have been shown to produce evidence of transmissible genetic damage. As a result, the research approach has been one in which macromolecular, cellular, and whole animal genetic studies have been combined to estimate genetic effects on humans following the deposition of radioactive materials in the body. The purpose of this report is to update the information available from animal and cellular experiments that relates genetic effects to deposited activity and dose from internally deposited radioactive materials

  14. Time-dependent deformation of a nonlinear viscoelastic rubber-toughened fiber composite with growing damage

    Science.gov (United States)

    Bocchieri, Robert Thomas

    One important factor in the durability of polymeric composites is their loss in stiffness over time due to many softening mechanisms, including nonlinear viscoelasticity, viscoplasticity and damage. Damage here refers to all ply-level microstructural changes such as matrix cracking, fiber-matrix debonding and shear yielding. This dissertation uses the theory previously established by Schapery (1999) to develop experimental and data analysis methods for isolating these softening effects. Schapery's constitutive theory is first tailored for a continuous fiber composite and evaluated for creep/recovery loading where nonlinear viscoelasticity, viscoplasticity and damage growth have a significant effect on strain. Numerical methods, implementing a Genetic Algorithm, are developed to fit material parameters in the recovery equations. This method successfully fits simulated recovery data with hereditary damage effects, but was not implemented on real data due to the unusually complex recovery behavior of the material studied. A method of Acoustic emission monitoring and waveform analysis is developed as a means for tracking two of the primary damage mechanisms in these materials, matrix-cracking and fiber/matrix debond. With direct monitoring, the extent of damage in the material does not need to be inferred from its effect on the stress-strain response. Unidirectional 30°, 45° and 90° coupons of a rubber-toughened carbon/epoxy are monitored in this way for various loading histories. A method of comparing waveforms from different samples is also suggested. An interpretation of the AE data is pro posed based on an initial population of existing flaws. Then a cumulative distribution function (CDF) of microcracking is defined and used to study effects of stress history. After developing an idealized model of the material consisting of two viscoelastic phases, a single loading parameter, which is theoretically independent of loading history and derived from viscoelastic

  15. Genetic Variability as a Regulator of TLR4 and NOD Signaling in Response to Bacterial Driven DNA Damage Response (DDR and Inflammation: Focus on the Gastrointestinal (GI Tract

    Directory of Open Access Journals (Sweden)

    Evagelia Spanou

    2017-05-01

    Full Text Available The fundamental role of human Toll-like receptors (TLRs and NOD-like receptors (NLRs, the two most studied pathogen recognition receptors (PRRs, is the protection against pathogens and excessive tissue injury. Recent evidence supports the association between TLR/NLR gene mutations and susceptibility to inflammatory, autoimmune, and malignant diseases. PRRs also interfere with several cellular processes, such as cell growth, apoptosis, cell proliferation, differentiation, autophagy, angiogenesis, cell motility and migration, and DNA repair mechanisms. We briefly review the impact of TLR4 and NOD1/NOD2 and their genetic variability in the process of inflammation, tumorigenesis and DNA repair, focusing in the gastrointestinal tract. We also review the available data on new therapeutic strategies utilizing TLR/NLR agonists and antagonists for cancer, allergic diseases, viral infections and vaccine development against both infectious diseases and cancer.

  16. Genetic Variability as a Regulator of TLR4 and NOD Signaling in Response to Bacterial Driven DNA Damage Response (DDR) and Inflammation: Focus on the Gastrointestinal (GI) Tract.

    Science.gov (United States)

    Spanou, Evagelia; Kalisperati, Polyxeni; Pateras, Ioannis S; Papalampros, Alexandros; Barbouti, Alexandra; Tzioufas, Athanasios G; Kotsinas, Athanassios; Sougioultzis, Stavros

    2017-01-01

    The fundamental role of human Toll-like receptors (TLRs) and NOD-like receptors (NLRs), the two most studied pathogen recognition receptors (PRRs), is the protection against pathogens and excessive tissue injury. Recent evidence supports the association between TLR/NLR gene mutations and susceptibility to inflammatory, autoimmune, and malignant diseases. PRRs also interfere with several cellular processes, such as cell growth, apoptosis, cell proliferation, differentiation, autophagy, angiogenesis, cell motility and migration, and DNA repair mechanisms. We briefly review the impact of TLR4 and NOD1/NOD2 and their genetic variability in the process of inflammation, tumorigenesis and DNA repair, focusing in the gastrointestinal tract. We also review the available data on new therapeutic strategies utilizing TLR/NLR agonists and antagonists for cancer, allergic diseases, viral infections and vaccine development against both infectious diseases and cancer.

  17. Studies of the repair of radiation-induced genetic damage in Drosophila Annual progress report, 1 November 1994 - 1 January 1996

    International Nuclear Information System (INIS)

    Hawley, R.S.

    1996-01-01

    The authors have recently cloned the mei-4l gene, and showed that its putative translation product is highly homologous to the ATM, MEC1, and RAD3 genes at the level of primary amino acid sequence. That this sequence similarity reflects a functional homology is suggested by three lines of evidence: (1) as is the case for the ATM gene, loss of function of mei-4l results in increased sensitivity to X-irradiation; (2) mutations in the mei-4l gene also resemble ATM mutations in that they cause high levels of chromosome breakage and genetic instability; and (3) like the ATM gene, the wild-type MEI-4l protein also plays a role in mediating the progression of the cell cycle

  18. Influence of some exo nucleases in response to the induced genetic damage in Escherichia coli by alpha radiation; Influencia de algunas exonucleasas en respuesta al dano genetico inducido en Escherichia coli por radiacion alfa

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar M, M

    2005-07-01

    Within the strategies with those that E. coli counts to overcome to the genetic damage there is the SOS response, a group of genes that participate in repair and/or tolerance that it confers to the bacteria major opportunities of surviving. These genes are repressed and its only are expressed when it happens genetic damage. So that this system is activated it is necessary that DNA of a band exists and in this sense the double ruptures (RDB) its are not able to induce this response unless there is a previous processing. In stumps with defects in certain genes that have to do with repair of RDB (as recO, recJ and xonA) the activity of SOS is smaller than in a wild stump what suggests that these participate in the previous processes to the activation of the response. The ionizing radiation produce among other many lesions, RDB in greater or smaller proportion, depending on the ionization capacity. A parameter to evaluate this capacity is the lineal energy transfer (LET), defined as the average energy given by unit of distance travelled. In general the LET of the corpuscular radiations is a lot but high that of the electromagnetic one, for what produces bigger quantity of ionizations inside a restricted zone and it increases by this way the probability that RDB has been generated. This work has for object to infer the participation of xonA and recJ in this response and to evaluate the damage produced by ionizing radiation of different LET (alpha particles of different energies) in a stump with all the functional repair mechanisms. Its were considered two parameters: the survival and the activity of SOS evaluated by means of the chromo test. The results indicate that the activity of these exo nucleases is necessary for the repair of RDB as well as for the processing of lesions foresaw to the activation of SOS. As for the treatment with alphas of different energies is observed that so much the survival like the activity of SOS vary as the LET of the radiation changes

  19. KFK Institute of Genetics and of Toxicology of Fission Materials. 1990 annual report on research and development work

    International Nuclear Information System (INIS)

    1991-03-01

    The annual report summarizes the R+D activities of the Institute performed in the year 1990 in accordance with the Institute's R+D framework. The activities cover studies on gene repair, gene regulation, biological carcinogenesis, molecular genetics of enkaryontic genes, genetic mouse models for the study of human disease, radiotoxicology of the actinides, cellular inhalation toxicology, cellular and molecular toxicology, fractionation and speciation of actinides in vivo. There is a bibliography of publications issued by members of the Institute in 1990 and of the IGT primary reports issued in 1989 and 1990, and a list of lectures held but not available in printed form. (VHE) [de

  20. Study on the mechanism for radiation/chemical substance-induced cellular damages and development of its risk assessment. Changes in telomere and telomerase in genetically modified animals

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Tohru; Ono, Atsushi; Hirabayashi, Yoko; Kitajima, Satoshi [National Inst. of Health Sciences, Tokyo (Japan)

    2000-02-01

    In the previous study, a highly sensitive system for determination of telomere length and telomerase assay was established. In this study, changes in the telomerase activity and the length of telomere following{gamma}-ray exposure were investigated and their correlation with deletion of p53 gene was examined using p53 knockout mice, of which carcinogenic sensitivity was very high. Early damages caused by radiation exposure generally appeared in the hematopoietic cells, the peripheral lymphocytes and bone marrow cells. The telomerase activity of peripheral lymphocytes was dose-dependently decreased in either of p53 +/+ or p53 -/-mouse, but the activities of exposed group and not-exposed reached almost the same level after 19 days in either of p53 +/+ and p53 -/- mouse. Whereas the length of the telomere was not affected by {gamma}-ray exposure at 500 cGy. The number of colony for p53 wild type cell culture was decreased to several percent, l 5 days after the exposure and it recovered on day 20. Whereas there was no apparent changes in the colony number of p53 -/-. The telomerase activity was lower in the order of p53 +/+, p53 +/-, p53 -/- mouse, indicating that the activity level was dependent on the presence of p53 gene. Therefore, it is likely that the activity of telomerase is controlled by p53 gene. (M.N.)

  1. Tort Damages

    NARCIS (Netherlands)

    L.T. Visscher (Louis)

    2008-01-01

    textabstractAbstract: In this Chapter, I provide an overview of Law and Economics literature regarding tort damages. Where necessary, attention is also spent to rules of tort liability. Both types of rules provide behavioral incentives to both injurers and victims, with respect to their level of

  2. Collaborative Research. Damage and Burst Dynamics in Failure of Complex Geomaterials. A Statistical Physics Approach to Understanding the Complex Emergent Dynamics in Near Mean-Field Geological Materials

    Energy Technology Data Exchange (ETDEWEB)

    Rundle, John B. [Univ. of California, Davis, CA (United States); Klein, William [Boston Univ., MA (United States)

    2015-09-29

    We have carried out research to determine the dynamics of failure in complex geomaterials, specifically focusing on the role of defects, damage and asperities in the catastrophic failure processes (now popularly termed “Black Swan events”). We have examined fracture branching and flow processes using models for invasion percolation, focusing particularly on the dynamics of bursts in the branching process. We have achieved a fundamental understanding of the dynamics of nucleation in complex geomaterials, specifically in the presence of inhomogeneous structures.

  3. 50. Brazilian congress on genetics. 50 years developing genetics. Abstracts

    International Nuclear Information System (INIS)

    2004-01-01

    Use of radioisotopes and ionizing radiations in genetics is presented. Several aspects related to men, animals,plants and microorganisms are reported highlighting biological radiation effects, evolution, mutagenesis and genetic engineering. Genetic mapping, gene mutations, genetic diversity, DNA damages, plant cultivation and plant grow are studied as well

  4. Water Damage Mitigation Drying Technology

    OpenAIRE

    Jones, Ed N.

    2014-01-01

    The water damage restoration industry has changed dramatically the last 10–15 years when looking at water damage mitigation technology and the perspective of restoring rather than removing and replacing affected materials. When there are weather-related catastrophes, like flooding, the porous materials in the affected structures will need to be removed and replaced in most cases, but the structural framing, which can generally be restored, can now be dried quicker using new and more effici...

  5. Institute for Genetics and Toxicology of Fission Materials. Annual report on research and development work in 1989

    International Nuclear Information System (INIS)

    1990-03-01

    The report covers the research results achieved in 1989 in the following subject fields: Gene repair and gene regulation, biological carcinogenesis, molecular genetics of eukaryontic genes, radiotoxicology of the actinides, cellular inhalation toxicology, cellular and molecular toxicology, and in vitro fractionation and speciation of actinides. A list of publications of the Institute in 1989 shows printed original reports and conference papers. (MG) [de

  6. Harmful Cyanobacterial Material Production in the North Han River (South Korea): Genetic Potential and Temperature-Dependent Properties.

    Science.gov (United States)

    Kim, Keonhee; Park, Chaehong; Yoon, Youngdae; Hwang, Soon-Jin

    2018-03-03

    Cyanobacteria synthesize various harmful materials, including off-flavor substances and toxins, that are regarded as potential socio-economic and environmental hazards in freshwater systems, however, their production is still not well understood. In this study, we investigated the potential and properties of harmful materials produced by cyanobacteria, depending on temperature, and undertook a phylogenetic analysis of cyanobacteria present in the North Han River (South Korea). Production potentials were evaluated using gene-specific probes, and the harmful material production properties of strains showing positive potentials were further characterized at different temperatures in the range 15 to 30 °C. We identified six cyanobacterial strains based on 16S rDNA analysis: two morphological types (coiled and straight type) of Dolichospermum circinale, Aphanizomenon flos-aquae, Oscillatoria limosa, Planktothricoides raciborskii, Pseudanabaena mucicola , and Microcystis aeruginosa . We confirmed that cyanobacterial strains showing harmful material production potential produced the corresponding harmful material, and their production properties varied with temperature. Total harmful material production was maximal at 20~25 °C, a temperature range optimal for cell growth. However, harmful material productivity was highest at 15 °C. These results indicate that the expression of genes related to synthesis of harmful materials can vary depending on environmental conditions, resulting in variable harmful material production, even within the same cyanobacterial strains.

  7. Damage growth in aerospace composites

    CERN Document Server

    2015-01-01

    This book presents novel methods for the simulation of damage evolution in aerospace composites that will assist in predicting damage onset and growth and thus foster less conservative designs which realize the promised economic benefits of composite materials. The presented integrated numerical/experimental methodologies are capable of taking into account the presence of damage and its evolution in composite structures from the early phases of the design (conceptual design) through to the detailed finite element method analysis and verification phase. The book is based on the GARTEUR Research Project AG-32, which ran from 2007 to 2012, and documents the main results of that project. In addition, the state of the art in European projects on damage evolution in composites is reviewed. While the high specific strength and stiffness of composite materials make them suitable for aerospace structures, their sensitivity to damage means that designing with composites is a challenging task. The new approaches describ...

  8. Repair of damaged DNA in vivo: Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Hanawalt, P.C.

    1987-09-01

    This contract was initiated in 1962 with the US Atomic Energy Commission to carry out basic research on the effects of radiation on the process of DNA replication in bacteria. Within the first contract year we discovered repair replication at the same time that Setlow and Carrier discovered pyrimidine dimer excision. These discoveries led to the elucidation of the process of excision-repair, one of the most important mechanisms by which living systems, including humans, respond to structural damage in their genetic material. We improved methodology for distinguishing repair replication from semiconservative replication and instructed others in these techniques. Painter then was the first to demonstrate repair replication in ultraviolet irradiated human cells. He, in turn, instructed James Cleaver who discovered that skin fibroblasts from patients with xeroderma pigmentosum were defective in excision-repair. People with this genetic defect are extremely sensitive to sunlight and they develop carcinomas and melanomas of the skin with high frequency. The existence of this hereditary disease attests to the importance of DNA repair in man. We certainly could not survive in the normal ultraviolet flux from the sun if our DNA were not continuously monitored for damage and repaired. Other hereditary diseases such as ataxia telangiectasia, Cockayne's syndrome, Blooms syndrome and Fanconi's anemia also involve deficiencies in DNA damage processing. The field of DNA repair has developed rapidly as we have learned that most environmental chemical carcinogens as well as radiation produce repairable damage in DNA. 251 refs.

  9. Repair of damaged DNA in vivo: Final technical report

    International Nuclear Information System (INIS)

    Hanawalt, P.C.

    1987-09-01

    This contract was initiated in 1962 with the US Atomic Energy Commission to carry out basic research on the effects of radiation on the process of DNA replication in bacteria. Within the first contract year we discovered repair replication at the same time that Setlow and Carrier discovered pyrimidine dimer excision. These discoveries led to the elucidation of the process of excision-repair, one of the most important mechanisms by which living systems, including humans, respond to structural damage in their genetic material. We improved methodology for distinguishing repair replication from semiconservative replication and instructed others in these techniques. Painter then was the first to demonstrate repair replication in ultraviolet irradiated human cells. He, in turn, instructed James Cleaver who discovered that skin fibroblasts from patients with xeroderma pigmentosum were defective in excision-repair. People with this genetic defect are extremely sensitive to sunlight and they develop carcinomas and melanomas of the skin with high frequency. The existence of this hereditary disease attests to the importance of DNA repair in man. We certainly could not survive in the normal ultraviolet flux from the sun if our DNA were not continuously monitored for damage and repaired. Other hereditary diseases such as ataxia telangiectasia, Cockayne's syndrome, Blooms syndrome and Fanconi's anemia also involve deficiencies in DNA damage processing. The field of DNA repair has developed rapidly as we have learned that most environmental chemical carcinogens as well as radiation produce repairable damage in DNA. 251 refs

  10. DNA damage in the oocytes SACs

    Czech Academy of Sciences Publication Activity Database

    Macůrek, Libor

    2016-01-01

    Roč. 15, č. 4 (2016), s. 491-492 ISSN 1538-4101 Institutional support: RVO:68378050 Keywords : DNA damage response * oocyte * meiosis * checkpoint Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.530, year: 2016

  11. Analysis of the concept of informed consent concerning the use of genetic material according to the European Convention on Bioethics and in other solutionsm - Propositions for broad consent for future genetic research from the point of view of the activity of the Biobank.

    Science.gov (United States)

    Patryn, Rafał; Sak, Jarosław

    2017-09-21

    The aim of the article is a critical presentation of the typology of consents included in the European Convention on Bioethics and in other formal solutions concerning the gathering of genetic material in institutions called Biobanks. Existing types of Acts of Consent are inaccurate in their scope and possess insufficient information regarding the gathering of genetic material (application, usage, processing) and their final (future and diverse) use. Lack of precise legal regulations on the broad future use of genetic material may result in various formal problems relating both to research participants as well as those commissioning the research. Ultimately, it may lead to various complications with the appropriate legal interpretation of consent and possible claims on behalf of the donors. The presented proposition of consent with a terminal premise is to be applied eventually to legal and formal aspects of the collecting of genetic material. It is a possible solution which would clarify the issue of informed consent, and may be implemented in the regulations of the Convention as well as constitute a self-contained legislative solution to this matter. For example, Polish law in its current form, without the ratification of the Bioethical Convention, allows the collecting of material for genetic testing for determination of the risk of genetic defects in common genetic material from people who are planning to have a child.

  12. Evaluation of the potential inhibitor of Ix (Pp-Ix) protoporphyrin of the genetic damage induced by gamma rays administered to different dose reasons in Drosophila melanogaster; Evaluacion del potencial inhibidor de la protoporfirina IX (PP-IX) del dano genetico inducido por rayos gama administrados a diferentes razones de dosis en Drosophila melanogaster

    Energy Technology Data Exchange (ETDEWEB)

    Flores A, J. A.

    2016-10-01

    Ionizing radiation can damage in DNA directly or indirectly by free radicals (Rl), characterized by unstable and highly reactive. To avoid damage by Rl the cell has endogenous antioxidants such as Sod, Cat, GSH or exogenous as some vitamins, but if with these mechanisms does not reach the cell homeostasis, the consequence may be the generation of chronic-disease degenerative such as cancer. This study was conducted in order to test the inhibitory role of Rl protoporphyrin Ix (Pp-Ix), induced by 20 Gy of gamma rays administered at different dose ratios using the assay of somatic mutation and recombination in the Drosophila wing. The results indicated that 20 Gy delivered at a rate of low dose (6.659 Gy/h), caused elevated frequencies of genetic damage (p <0.001), compared with those that induced a high dose reason (1111.42 Gy/h) in larvae of 48 h old. The difference is probably due to an indirect damage by Rl; when this hypothesis was approved with the possible inhibitor role of Pp-Ix (0.69 m M), damage was increased with the two reasons of tested doses. This result may be due to: 1) the Pp-Ix is not a good inhibitor of Rl, 2) the difference in the frequency of mutation found with both dose reasons, not due to Rl so that this compound did not reduce the genetic damage, and 3) that Pp-Ix acts as pro oxidant. (Author)

  13. Early resin luting material damage around a circular fiber post in a root canal treated premolar by using micro-computerized tomographic and finite element sub-modeling analyses.

    Science.gov (United States)

    Chang, Yen-Hsiang; Lee, Hao; Lin, Chun-Li

    2015-11-01

    This study utilizes micro-computerized tomographic (micro-CT) and finite element (FE) sub-modeling analyses to investigate the micro-mechanical behavior associated with voids/bubbles stress behavior at the luting material layer to understand the early damage in a root canal treated premolar. 3-dimensional finite element (FE) models of a macro-root canal treated premolar and two sub-models at the luting material layer to provide the void/bubble distribution and dimensions were constructed from micro-CT images and simulated to receive axial and lateral forces. The boundary conditions for the sub-models were determined from the macro-premolar model results and applied in sub-modeling analysis. The first principal stresses for the dentin, luting material layer and post in macro-premolar model and for luting material void/bubble in sub-models were recorded. The simulated results revealed that the macro-premolar model dramatically underestimated the luting material stress because the voids/bubbles at the adhesive layer cannot be captured due to coarse mesh and high stress gradient and the variations between sub- and macro-models ranging from 2.65 to 4.5 folds under lateral load at the mapping location. Stress concentrations were found at the edge of the voids/bubbles and values over 20 MPa in sub-modeling analysis immediately caused the luting material failure/micro-crack. This study establishes that micro-CT and FE sub-modeling techniques can be used to simulate the stress pattern at the micro-scale luting material layer in a root canal treated premolar, suggesting that attention must be paid to resin luting material initial failure/debonding when large voids/bubbles are generated during luting procedures. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Development of a Continuum Damage Mechanics Material Model of a Graphite-Kevlar(Registered Trademark) Hybrid Fabric for Simulating the Impact Response of Energy Absorbing Kevlar(Registered Trademark) Hybrid Fabric for Simulating the Impact Response of Energy Absorbing

    Science.gov (United States)

    Jackson, Karen E.; Fasanella, Edwin L.; Littell, Justin D.

    2017-01-01

    This paper describes the development of input properties for a continuum damage mechanics based material model, Mat 58, within LS-DYNA(Registered Trademark) to simulate the response of a graphite-Kevlar(Registered Trademark) hybrid plain weave fabric. A limited set of material characterization tests were performed on the hybrid graphite-Kevlar(Registered Trademark) fabric. Simple finite element models were executed in LS-DYNA(Registered Trademark) to simulate the material characterization tests and to verify the Mat 58 material model. Once verified, the Mat 58 model was used in finite element models of two composite energy absorbers: a conical-shaped design, designated the "conusoid," fabricated of four layers of hybrid graphite-Kevlar(Registered Trademark) fabric; and, a sinusoidal-shaped foam sandwich design, designated the "sinusoid," fabricated of the same hybrid fabric face sheets with a foam core. Dynamic crush tests were performed on components of the two energy absorbers, which were designed to limit average vertical accelerations to 25- to 40-g, to minimize peak crush loads, and to generate relatively long crush stroke values under dynamic loading conditions. Finite element models of the two energy absorbers utilized the Mat 58 model that had been verified through material characterization testing. Excellent predictions of the dynamic crushing response were obtained.

  15. The Potential for Genetic Control of Malaria-Transmitting Mosquitoes. Report of a Consultants Group Meeting. Working Material

    International Nuclear Information System (INIS)

    1993-01-01

    Since the beginning of the Joint FAO/IAEA Division Programme on the research and development of insect pest control methodology, emphasis has been placed on the basic and applied aspects of implementing the Sterile Insect Technique (SIT). Special emphasis has always been directed at the assembly of technological progress into workable systems that can be implemented in developing countries. The general intention is to solve problems associated with insect pests that have an adverse impact on public health and the production of food and fibre. For certain insects, SIT has proven to be a powerful method for control, but for a variety of reasons this technology has not been tried on an operational scale for most of the pest species of insects that exact a toll on the endeavors of humans. The Joint FAO/IAEA Division convened a Consultants Group Meeting to examine 'The Potential for Genetic Control of Malaria-Transmitting Mosquitoes', with emphasis to be placed on the SIT. A group of five scientists met, 26-30 April 1993, to examine the current status and the future potential of genetic control for malaria mosquitoes. In most of the tropical, developing countries, and to some extent in temperate regions of the world, Anopheles mosquitoes cause havoc by transmitting malaria, a dreaded disease that causes high mortality amongst children and diminishes productivity of adults. The importance of malaria as a deterrent to further economic growth in a large part of the world cannot be over-emphasized. Malaria is a severe problem because there are inadequacies in the technology available for control. As a result of the deliberations at the meeting, the consultants prepared a list of recommendations concerning the consensus opinions about the development of genetic control for malaria vector control. This report presents the findings and recommendations of the Consultants Group Meeting.

  16. Characterization of textural and hydric heterogeneities in argillaceous geo-materials using induced polarization method: application to the excavation damaged zone (EDZ) of the Tournemire experimental station

    International Nuclear Information System (INIS)

    Okay, Gonca

    2011-01-01

    This Ph-D thesis investigates the potential of clay rocks for deep geological disposal of radioactive waste. Underground excavations are responsible in their vicinity a region, where the clay-rock is damaged or disturbed. This region must to be characterized to ensure the safety of repositories. The extension of the excavation damaged zone (EDZ) and its evolution over time have been investigated thought electrical resistivity and induced polarization methods from three galleries belonging to the French Institute of Radioprotection and Nuclear Safety (IRSN)'s experimental underground research laboratory of Tournemire (Aveyron, France). Time domain induced polarisation indicates the presence of mineralization (e.g., especially pyrite) located in the structural discontinuities such as tectonic fractures (mm-cm), tectonic fault (m) and calcareous nodules (cm). Combined electrical resistivity and Induced Polarization methods show the possibility to delineate textural changes associated to desaturation of the clay-rock induced by the ventilation of galleries. The impact of the desaturation is particularly observed on the gallery's walls. In addition, Spectral Induced Polarization (SIP) tomography results can be used to discriminate the responses of the de-saturated zones from the fractured zones. We have performed laboratory experiments (in the range 1.4 mHz - 12 kHz) using saturated unconsolidated sand-clay mixtures. The results illustrate that the amplitude of polarization is strongly affected by the surface properties of these mixtures (e.g., cation exchange capacity, specific surface area) and by the volumetric clay content. However, the amplitude of polarization is independent of the concentration of electrolyte. The SIP response is also strongly sensitive to the mineralogy of the clays. (author)

  17. DETERIORO GENÓMICO Y MANIPULACIÓN GENÉTICA: DESEQUILIBRIO EN LA PRIORIDAD DE LAS AGENDAS PÚBLICAS DETERIORIZAÇÃO GENÔMICA E MANIPULAÇÃO GENÉTICA: DESEQUILÍBRIO NA PRIORIDADE DAS AGENDAS PÚBLICAS GENOME DAMAGE AND GENETIC MANIPULATION: UNBALANCE IN PUBLIC POLICIES PRIORITY

    Directory of Open Access Journals (Sweden)

    Elio A Prieto González

    2007-11-01

    Full Text Available Se analiza el desequilibrio en el tratamiento de dos temas que atañen a la conservación de la integridad del genoma humano: las tecnologías de manipulación genética y el deterioro genómico provocado por la contaminación ambiental. Las carencias educativas, la falta de información asentada en los hechos y un manejo sensacionalista en los medios, entre otros factores, desajustan las agendas mediáticas con las necesidades públicas, lo que desemboca en una falta de conciencia ciudadana acerca de las verdaderas amenazas a las que está expuesto el material genético y los riesgos de salud que ello implicaO presente texto analisa o desequilíbrio no tratamento de dois temas que dizem respeito à conservação da integridade do genoma humano: as tecnologias de manipulação genética e a deteriorização genômica provocada pela contaminação ambiental. As carências educativas, a falta de informação assentada nos fatos e um manejo sensacionalista dos meios, entre outros fatores, desajustam as agendas mediáticas com as necessidades públicas, o que desemboca numa falta de consciência cidadã em relação às verdadeiras ameaças à que se expôs o material genético e os riscos de saúde que isto implicaUnbalance in the treatment of two topics related to the conservation of the human genome integrity is analyzed here: the technologies for genetic manipulation and genome damage due to environmental pollution. Lack of education and of information based on real facts, and the media sensationalist treatment, among other factors, provoke an unbalance between the media agenda and public needs. This leads to a lack of citizenship consciousness over the true threats that genetic material faces and the health risks that it involves

  18. A theoretical introduction to "combinatory SYBRGreen qPCR screening", a matrix-based approach for the detection of materials derived from genetically modified plants.

    Science.gov (United States)

    Van den Bulcke, Marc; Lievens, Antoon; Barbau-Piednoir, Elodie; MbongoloMbella, Guillaume; Roosens, Nancy; Sneyers, Myriam; Casi, Amaya Leunda

    2010-03-01

    The detection of genetically modified (GM) materials in food and feed products is a complex multi-step analytical process invoking screening, identification, and often quantification of the genetically modified organisms (GMO) present in a sample. "Combinatory qPCR SYBRGreen screening" (CoSYPS) is a matrix-based approach for determining the presence of GM plant materials in products. The CoSYPS decision-support system (DSS) interprets the analytical results of SYBRGREEN qPCR analysis based on four values: the C(t)- and T(m) values and the LOD and LOQ for each method. A theoretical explanation of the different concepts applied in CoSYPS analysis is given (GMO Universe, "Prime number tracing", matrix/combinatory approach) and documented using the RoundUp Ready soy GTS40-3-2 as an example. By applying a limited set of SYBRGREEN qPCR methods and through application of a newly developed "prime number"-based algorithm, the nature of subsets of corresponding GMO in a sample can be determined. Together, these analyses provide guidance for semi-quantitative estimation of GMO presence in a food and feed product.

  19. 7 CFR 51.3064 - Damage.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Damage. 51.3064 Section 51.3064 Agriculture... Standards for Florida Avocados Definitions § 51.3064 Damage. Damage means any defect which materially... appearance of the avocados in the container. Any one of the following defects, or any combination of defects...

  20. An application of cost-effectiveness analysis to restrict the damage caused by an accidental release of radioactive material to the environment

    International Nuclear Information System (INIS)

    Frittelli, L.; Tamburrano, A.

    1980-01-01

    When an accidental release of radioactive material occurs health effects in the exposed population can be mitigated by remedial actions applied to individuals or their environment. A cost-effectiveness analysis is performed by comparing the cost of remedial action with the monetary value of the collective dose avoided. (H.K.)

  1. An analysis of US fertility centre educational materials suggests that informed consent for preimplantation genetic diagnosis may be inadequate.

    Science.gov (United States)

    LaBonte, Michelle Lynne

    2012-08-01

    The use of preimplantation genetic diagnosis (PGD) has expanded both in number and scope over the past 2 decades. Initially carried out to avoid the birth of children with severe genetic disease, PGD is now used for a variety of medical and non-medical purposes. While some human studies have concluded that PGD is safe, animal studies and a recent human study suggest that the embryo biopsy procedure may result in neurological problems for the offspring. Given that the long-term safety of PGD has not been clearly established in humans, this study sought to determine how PGD safety is presented to prospective patients by means of a detailed website analysis. The websites of 262 US fertility centres performing PGD were analysed and comments about safety and risk were catalogued. Results of the analysis demonstrated that 78.2% of centre websites did not mention safety or risk of PGD at all. Of the 21.8% of centres that did contain safety or risk information about PGD, 28.1% included statements highlighting the potential risks, 38.6% presented information touting the procedure as safe and 33.3% included statements highlighting potential risks and the overall safety of the procedure. Thus, 86.6% of PGD-performing centres state that PGD is safe and/or fail to disclose any risks on their websites despite the fact that the impact of the procedure on the long-term health of offspring is unproven. This lack of disclosure suggests that informed consent is inadequate; this study examines numerous factors that are likely to inhibit comprehensive discussions of safety.

  2. Polymerase chain reaction assay for the detection of human papillomavirus type 16 genetic material in the intraoperative material from patients with prostate cancer

    Directory of Open Access Journals (Sweden)

    G. M. Volgareva

    2017-01-01

    Full Text Available Background. The high rates of prostate cancer (PC morbidity and mortality, as well as their high growth rates suggest that investigations of the nature of PC are of importance. The possible association of PC with high-risk human papillomaviruses (HPV remains open.Objective: to examine surgically removed prostate tissue from patients with PC for HPV 16 type E7 oncogene, the main type of HPV being responsible for cervical cancer.Materials and methods. Polymerase chain reaction was used to test the prostate tissues removed from 17 patients with PC during radical prostatectomy. Cryopreserved (formalin- and paraffin- untreated tumor samples were employed for better preservation of DNA. The multifocal growth pattern typical of PC was taken into account using microdissection to accumulate homogeneous prostate cancer, dysplastic, and intact epithelial cells.Results. HPV 16 type E7 oncogene DNA was detected in the samples from 7 patients with PC out of the 17 examinees, including all 5 cases where DNA had been isolated from the homogeneous regions of PC.Conclusion. The finding may suggest that HPV 16 is frequently present in the prostate glands of Russian patients with PC.

  3. Radiation damage of construction materials, Phase II/1, Travel report on visit to Saclay related to VISA-2 project, 15.I-16.III 1964

    International Nuclear Information System (INIS)

    Marinkovic, S.

    1964-05-01

    Within the VISA-2 project, domestic reactor graphite was irradiated in the RA reactor and properties of this material after irradiation were tested in Saclay. Properties of graphite samples produced in Yugoslavia and in USSR were measured before irradiation in Saclay. Then they have been prepared placed in capsules for irradiation in the RA reactor. Final judgment of the quality of the graphite would be possible after testing the irradiated samples

  4. Research into damage - avoiding damage

    International Nuclear Information System (INIS)

    1980-01-01

    The brochure reports on the work of five European materials testing institutions. Subjects covered are prevention of accidents and catastrophies, energy conservation, environmental pollution, and the safeguarding of values of national economy. (RW) [de

  5. BEATRIX-II Program: ANNEX-III to IEA implementing agreement for a programme of research and development on radiation damage in fusion materials

    Energy Technology Data Exchange (ETDEWEB)

    Slagle, O.D.; Hollenberg, G.W.

    1992-12-01

    The BEATRIX-II experiment is an International Energy Agency (IEA) sponsored collaborative experiment between Japan, Canada, and the United States. This is an in situ tritium recovery experiment conducted to evaluate the performance of ceramic solid breeder materials in a fast neutron environment to high burnup levels. The experiment was carried out in the Fast Flux Test Facility (FFTF), located on the Hanford site near Richland, Washington, and was operated by Westinghouse Hanford Company (WHC). Pacific Northwest Laboratory, Richland (PNL), Richland, Washington, together with the Japan Atomic Energy Research Institute (JAERI) and Atomic Energy of Canada Limited (AECL) Research are conducting the experiment. The objective of the BEATRIX-II experiment is to design, conduct, and evaluate the in situ recovery of tritium from solid breeder materials during neutron irradiation in the FFTF. During the experiment, the performance of candidate solid breeder materials is continuously monitored with respect to temperature stability and tritium release. The phase I experiment was irradiated to lithium burnups of 5% while the goal for Phase II was to irradiate to burnups as high as 8%.

  6. [Economic damage caused by lowered prices in the agro-food sector in areas contaminated by radioactive materials leaked from the nuclear power plant severely damaged by the 2011 Great East Japan Earthquake--consideration from the viewpoints of epidemiology, economics and social psychology].

    Science.gov (United States)

    Sugita, Minoru; Miyakawa, Michiko

    2013-01-01

    Large amounts of radioactive materials were leaked into the environment from the Fukushima Daiichi Nuclear Power Plant (FDNPP) of the Tokyo Electric Power Company, which was severely damaged by the 2011 Tohoku Region Pacific Coast Earthquake and accompanying tsunami. Economic damage due to lowered prices and supplies of food products produced in the areas contaminated by the radioactive materials leaked from the damaged FDNPP to the agro-food sector in the affected areas is notable. In Japanese, this is known as fuhyo higai. In this study, we investigated fuhyo higai from the viewpoints of epidemiology, economics, and social psychology in an effort to seek solutions. Information was obtained from articles in print and on the Internet. Fuhyo higai, or economic damage of the agro-food sector, which is the main industry in the contaminated areas, is serious because it is difficult to reassure the general population regarding food safety. This fuhyo higai does not derive solely from rumor. It has been reported that improving the science literacy of the general population is important as a countermeasure against fuhyo higai, but this may not be effective because of the human social structure and behavior of people who seek subjective safety. Almost all radiological laboratory results of samples of food produced in the contaminated areas were below detectable limits. Very high values were rarely detected. In general, information about the dose-response relationship is obtained under the assumption that there may be error in the response but not in the dose. The rare cases of extremely high radiological values of food samples from the contaminated areas may correspond to large errors in dose. However, it is difficult to deny a high-dose risk. The reported information on the dose-response relationship obtained under the assumption that there is no error in dose is not sufficient. Thus, response, i.e., health risk, cannot be correctly estimated. This leads the general

  7. Supplementary Material for: Recombination in pe/ppe genes contributes to genetic variation in Mycobacterium tuberculosis lineages

    KAUST Repository

    Phelan, Jody

    2016-01-01

    Abstract Background Approximately 10 % of the Mycobacterium tuberculosis genome is made up of two families of genes that are poorly characterized due to their high GC content and highly repetitive nature. The PE and PPE families are typified by their highly conserved N-terminal domains that incorporate proline-glutamate (PE) and proline-proline-glutamate (PPE) signature motifs. They are hypothesised to be important virulence factors involved with host-pathogen interactions, but their high genetic variability and complexity of analysis means they are typically disregarded in genome studies. Results To elucidate the structure of these genes, 518 genomes from a diverse international collection of clinical isolates were de novo assembled. A further 21 reference M. tuberculosis complex genomes and long read sequence data were used to validate the approach. SNP analysis revealed that variation in the majority of the 168 pe/ppe genes studied was consistent with lineage. Several recombination hotspots were identified, notably pe_pgrs3 and pe_pgrs17. Evidence of positive selection was revealed in 65 pe/ppe genes, including epitopes potentially binding to major histocompatibility complex molecules. Conclusions This, the first comprehensive study of the pe and ppe genes, provides important insight into M. tuberculosis diversity and has significant implications for vaccine development.

  8. Xenografting of sheep testis tissue and isolated cells as a model for preservation of genetic material from endangered ungulates.

    Science.gov (United States)

    Arregui, Lucía; Rathi, Rahul; Megee, Susan O; Honaramooz, Ali; Gomendio, Montserrat; Roldan, Eduardo R S; Dobrinski, Ina

    2008-07-01

    Recovery of germ cells could be an option for preservation of the genetic pool of endangered animals. In immature males, xenografting of testis tissue provides the opportunity to recover sperm from these animals. In adult animals, xenografting has been less successful, but de novo morphogenesis of functional testis tissue from dissociated testis cells could be an alternative. To assess the potential use of these techniques in endangered bovid species, the domestic sheep was used as a model. Testes from 2-week-old lambs were grafted as tissue fragments or cell suspensions into nude mice. Grafts were recovered at 4, 8, 12 and 16 weeks post grafting. For isolated cells, two additional time points at 35 and 40 weeks after grafting were added. In addition, to analyse the possible effect of social stress among mice within a group on the development of the grafts, testis tissue grafts were recovered 13 weeks post grafting from mice housed individually and in groups. Complete spermatogenesis occurred in sheep testis xenografts at 12 weeks, similar to the situation in situ. Isolated sheep testis cells were able to reorganize and form functional testicular tissue de novo. Housing mice individually or in groups did not have any effect on the development of xenografts. Xenografting of testis tissue might be useful to obtain sperm from immature endangered ungulates that die prematurely. Testis tissue de novo morphogenesis from isolated cells could open interesting options to recover germ cells from mature males with impaired spermatogenesis.

  9. Design and construction of an irradiation apparatus with controlled atmosphere and temperature for radiation damage evaluation of nuclear materials in the IEA-R1 research reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lucki, Georgi; Silva, Jose Eduardo Rosa da; Castanheira, Myrthes; Terremoto, Luis Antonio Albiac; Teodoro, Celso Antonio; Silva, Antonio Teixeira e; Damy, Margaret de Almeida [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: glucki@ipen.br

    2005-07-01

    A material irradiation apparatus CIMAT (Capsula de Irradiacao de Materiais) with controlled temperature and atmosphere is described. The device was specifically designed to perform experiments inside the core of the IEA-R1 swimming pool reactor and allows fast neutron (E=1 MeV) irradiations of multiple miniature metallic samples at temperature between 100 deg C and 500 deg C, in Argon or Helium atmosphere to inhibit corrosion. The aim of CIMAT is to make a comparative assessment of Radiation Embrittlement (RE) on the AS 508 cl.3 steel, of different origins (ELETROMETAL-Brazil and VITCOVICE-Chekia) used in Pressure Vessels (PV) of PWR, for fluence of 10 exp 19 nvt at 300 C, by means of mechanical post irradiation evaluation. Previous characterization of non-irradiated samples of these materials is presented. In situ electrical and magnetic measurements, at high temperatures, are foreseen to be made with this apparatus. Extensive temperature stability and leak-tightness tests performed in the reactor swimming pool have proven the CIMAT to be intrinsically safe and operational. (author)

  10. Design and construction of an irradiation apparatus with controlled atmosphere and temperature for radiation damage evaluation of nuclear materials in the IEA-R1 research reactor

    International Nuclear Information System (INIS)

    Lucki, Georgi; Silva, Jose Eduardo Rosa da; Castanheira, Myrthes; Terremoto, Luis Antonio Albiac; Teodoro, Celso Antonio; Silva, Antonio Teixeira e; Damy, Margaret de Almeida

    2005-01-01

    A material irradiation apparatus CIMAT (Capsula de Irradiacao de Materiais) with controlled temperature and atmosphere is described. The device was specifically designed to perform experiments inside the core of the IEA-R1 swimming pool reactor and allows fast neutron (E=1 MeV) irradiations of multiple miniature metallic samples at temperature between 100 deg C and 500 deg C, in Argon or Helium atmosphere to inhibit corrosion. The aim of CIMAT is to make a comparative assessment of Radiation Embrittlement (RE) on the AS 508 cl.3 steel, of different origins (ELETROMETAL-Brazil and VITCOVICE-Chekia) used in Pressure Vessels (PV) of PWR, for fluence of 10 exp 19 nvt at 300 C, by means of mechanical post irradiation evaluation. Previous characterization of non-irradiated samples of these materials is presented. In situ electrical and magnetic measurements, at high temperatures, are foreseen to be made with this apparatus. Extensive temperature stability and leak-tightness tests performed in the reactor swimming pool have proven the CIMAT to be intrinsically safe and operational. (author)

  11. Genetic Damage Induced by Accidental Environmental Pollutants

    OpenAIRE

    Beatriz Pérez-Cadahía; Blanca Laffon; Eduardo Pásaro; Josefina Méndez

    2006-01-01

    Petroleum is one of the main energy sources worldwide. Its transport is performed by big tankers following some established marine routes. In the last 50 years a total amount of 37 oil tankers have given rise to great spills in different parts of the world, Prestige being the last one. After the accident, a big human mobilisation took place in order to clean beaches, rocks and fauna, trying to reduce the environmental consequences of this serious catastrophe. These people were exposed to the ...

  12. Structural damage

    International Nuclear Information System (INIS)

    Gray, R.E.; Bruhn, R.W.

    1992-01-01

    Virtually all structures show some signs of distress due to deterioration of the building components, to changed loads, or to changed support conditions. Changed support conditions result from ground movements. In mining regions many cases of structural distress are attributed to mining without considering alternative causes. This is particularly true of coal mining since it occurs under extensive areas. Coal mining is estimated to have already undermined more than eight million acres and may eventually undermine 40 million acres in the United States. Other nonmetal and metal underground mines impact much smaller areas. Although it is sometimes difficult, even with careful study, to identify the actual cause of damage, persons responsible for underground coal mining should at least be aware of possible causes of building stress other than mine subsidence. This paper presents information on distress to structures and briefly reviews a number of causes of ground movements other than subsidence: Mass movements, dissolution, erosion, frost action, shrinking and swelling, yield into excavations and compressibility

  13. Damaged Skylab

    Science.gov (United States)

    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.

  14. Development and Genetic Characterization of Advanced Backcross Materials and An Introgression Line Population of Solanum incanum in a S. melongena Background

    Directory of Open Access Journals (Sweden)

    Pietro Gramazio

    2017-08-01

    Full Text Available Advanced backcrosses (ABs and introgression lines (ILs of eggplant (Solanum melongena can speed up genetics and genomics studies and breeding in this crop. We have developed the first full set of ABs and ILs in eggplant using Solanum incanum, a wild eggplant that has a relatively high tolerance to drought, as a donor parent. The development of these ABs and IL eggplant populations had a low efficiency in the early stages, because of the lack of molecular markers and genomic tools. However, this dramatically improved after performing genotyping-by-sequencing in the first round of selfing, followed by high-resolution-melting single nucleotide polymorphism genotyping in subsequent selection steps. A set of 73 selected ABs covered 99% of the S. incanum genome, while 25 fixed immortal ILs, each carrying a single introgressed fragment in homozygosis, altogether spanned 61.7% of the S. incanum genome. The introgressed size fragment in the ILs contained between 0.1 and 10.9% of the S. incanum genome, with a mean value of 4.3%. Sixty-eight candidate genes involved in drought tolerance were identified in the set of ILs. This first set of ABs and ILs of eggplant will be extremely useful for the genetic dissection of traits of interest for eggplant, and represents an elite material for introduction into the breeding pipelines for developing new eggplant cultivars adapted to the challenges posed by the climate-change scenario.

  15. Development and Genetic Characterization of Advanced Backcross Materials and An Introgression Line Population of Solanum incanum in a S. melongena Background

    Science.gov (United States)

    Gramazio, Pietro; Prohens, Jaime; Plazas, Mariola; Mangino, Giulio; Herraiz, Francisco J.; Vilanova, Santiago

    2017-01-01

    Advanced backcrosses (ABs) and introgression lines (ILs) of eggplant (Solanum melongena) can speed up genetics and genomics studies and breeding in this crop. We have developed the first full set of ABs and ILs in eggplant using Solanum incanum, a wild eggplant that has a relatively high tolerance to drought, as a donor parent. The development of these ABs and IL eggplant populations had a low efficiency in the early stages, because of the lack of molecular markers and genomic tools. However, this dramatically improved after performing genotyping-by-sequencing in the first round of selfing, followed by high-resolution-melting single nucleotide polymorphism genotyping in subsequent selection steps. A set of 73 selected ABs covered 99% of the S. incanum genome, while 25 fixed immortal ILs, each carrying a single introgressed fragment in homozygosis, altogether spanned 61.7% of the S. incanum genome. The introgressed size fragment in the ILs contained between 0.1 and 10.9% of the S. incanum genome, with a mean value of 4.3%. Sixty-eight candidate genes involved in drought tolerance were identified in the set of ILs. This first set of ABs and ILs of eggplant will be extremely useful for the genetic dissection of traits of interest for eggplant, and represents an elite material for introduction into the breeding pipelines for developing new eggplant cultivars adapted to the challenges posed by the climate-change scenario. PMID:28912788

  16. Comparison of the creep and damage failure prediction of the new, service-aged and repaired thick-walled circumferential CrMoV pipe welds using material properties at 640degC

    Energy Technology Data Exchange (ETDEWEB)

    Sun, W.; Hyde, T.H.; Becker, A.A. [Nottingham Univ., School of Mechanical, Materials, Manufacturing Engineering and Management, Nottingham (United Kingdom); Williams, J.A.

    2000-06-01

    Finite element creep and damage analyses were performed for a series of new, service-aged, fully repaired and partially repaired circumferential welds in CrMoV main steam pipes, under an internal pressure and a uniform axial stress, using simplified axisymmetric models. The material properties used were those of a 1/2Cr1/2Mo1/4V: 2 1/4Cr1Mo weldment at 640degC. Failure lives and failure positions were obtained using damage modelling and these were compared with corresponding results obtained from steady-state analyses. The effect of the weld width, in the practical range, and the effect of the axial (system) loading, on the failure life and position, of the various weld situations were also investigated. Comparison of the various failure predictions allows the effects of the differences in the relative properties of the constituents of the weld, the geometry and system loading, to be identified. The information is useful for assessing the performance of practical service-aged/repaired welds in power plants pipework. (Author)

  17. The law concerning indemnification of nuclear damage

    International Nuclear Information System (INIS)

    1977-01-01

    This Law aims at determining the basic system concerning indemnification for nuclear damage caused by the operation of reactors, fabrication, reprocessing and use of nuclear fuel materials as well as the transportation, storing or disposal of such materials or those contaminated by such materials (including fission products) accompanying these operations in view of protecting the sufferers and contributing to the wholesome development of atomic energy enterprises. The ''nuclear damage'' referred to in this Law is the damages caused by the action during the process of fission of nuclear fuel materials or the action of radiation or the poisonous action of said nuclear fuel materials or matters contaminated by said materials (those causing poisoning or deuteropathy in human bodies by taking in or inhaling such materials). Upon giving nuclear damage by the operation of reactors and others, the atomic energy entrepreneurs concerned are responsible for indemnifying the damage. Atomic energy entrepreneurs should not operate reactors without first taking the measures for indemnifying nuclear damages. Said measures are conclusion of nuclear damage indemnification responsibility insurance contract and nuclear damage indemnification contract or deposit, by which 6,000 million yen may be earmarked for such indemnification per factory, place of business or nuclear ship

  18. Genetic Variance in Cadmium Tolerance and Accumulation in Wheat Materials Differing in Ploidy and Genome at Seedling Stage

    DEFF Research Database (Denmark)

    Ci, D; Jiang, D; Wollenweber, B

    2010-01-01

    and cluster analysis, Triticum boeoticum Boiss was found to be the most Cd-tolerant variety exhibiting low Cd translocation rates, whereas T. aestivum cv. Huixianhong and Jinghui 1 were identified as the most Cd-sensitive varieties showing also higher Cd translocation rates.......Cadmium (Cd) tolerance and accumulation in wheat varieties differing in ploidy and genome were investigated at seedling stage under controlled environmental conditions. The wheat varieties included six diploid, eight tetraploid, seven hexaploid and three octoploid species together with wheat...... translocation (ratio of SCA to total Cd accumulation in plants) of the wheat varieties differing in ploidies generally decreased from octoploid to diploid, except for material containing the CCUU genome. It was found that Cd tolerance of these 24 wheat varieties varied with different ploidy and genomes...

  19. Evalution of DNA extraction methods in order to monitor genetically modified materials in soy foodstuffs and feeds commercialised in Turkey by multiplex real-time PCR.

    Science.gov (United States)

    Turkec, Aydin; Kazan, Hande; Baykut, Aykut; Lucas, Stuart J

    2015-01-01

    Soybean is one of the most important biotech crops, widely used as an ingredient in both foodstuffs and feed. DNA extraction methods have been evaluated to detect the presence of genetically modified (GM) materials in soya-containing food and feed products commercialised in Turkey. All extraction methods performed well for the majority of soya foods and feed products analysed. However, the most successful method varied between different products; the Foodproof, Genespin and the cetyltrimethylammonium bromide (CTAB) methods each produced the highest DNA yield and purity for different soya foodstuffs and feeds. Of the samples tested, 20% were positive for the presence of at least two GM elements (35S/NOS) while 11% contained an additional GM element (35S/NOS/FMV). Of the tested products, animal feeds showed a larger prevalence of GM material (50%) than the soya-containing foodstuffs (13%). The best performing extraction methods proved to be the Foodproof, Genespin and CTAB methods for soya-containing food and feed products. The results obtained herein clearly demonstrate the presence of GM soybean in the Turkish market, and that the Foodproof GMO Screening Kit provides reliable screening of soy-containing food and feed products. © 2014 Society of Chemical Industry.

  20. Packaging materials for plasma sterilization with the flowing afterglow of an N{sub 2}-O{sub 2} discharge: damage assessment and inactivation efficiency of enclosed bacterial spores

    Energy Technology Data Exchange (ETDEWEB)

    Levif, P; Moisan, M; Soum-Glaude, A [Groupe de Physique des Plasmas, Universite de Montreal, CP 6128, Succursale Centre-Ville, Montreal H3C 3J7, Quebec (Canada); Seguin, J; Barbeau, J, E-mail: michel.moisan@umontreal.ca [Faculte de Medecine Dentaire, Laboratoire de Controle des Infections, Universite de Montreal, CP 6128, Montreal H3C 3J7, Quebec (Canada)

    2011-10-12

    In conventional sterilization methods (steam, ozone, gaseous chemicals), after their proper cleaning, medical devices are wrapped/enclosed in adequate packaging materials, then closed/sealed before initiating the sterilization process: these packaging materials thus need to be porous. Gaseous plasma sterilization being still under development, evaluation and comparison of packaging materials have not yet been reported in the literature. To this end, we have subjected various porous packagings used with conventional sterilization systems to the N{sub 2}-O{sub 2} flowing afterglow and also a non-porous one to evaluate and compare their characteristics towards the inactivation of B. atrophaeus endospores deposited on a Petri dish and enclosed in such packagings. Because the sterilization process with the N{sub 2}-O{sub 2} discharge afterglow is conducted under reduced-pressure conditions, non-porous pouches can be sealed only after returning to atmospheric pressure. All the tests were therefore conducted with one end of the packaging freely opened, post-sealing being required. The features of these packaging materials, namely mass loss, resistance, toxicity to human cells as well as some characteristics specific to the plasma method used such as ultraviolet transparency, were examined before and after exposure to the flowing afterglow. All of our results show that the non-porous packaging considered is much more suitable than the conventionally used porous ones as far as ensuring an efficient and low-damage sterilization process with an N{sub 2}-O{sub 2} plasma-afterglow is concerned.