WorldWideScience

Sample records for aging materials

  1. Research projects on life management: materials ageing

    International Nuclear Information System (INIS)

    Gomez Briceno, D.

    1997-01-01

    Materials ageing is a time-dependent process, that involves the loss of availability of nuclear plants. Radiation embrittlement, stress corrosion cracking, irradiation assisted stress corrosion cracking, and thermal ageing are the most relevant time-dependent material degradation mechanisms that can be identified in the materials ageing process. The Materials Programme of Nuclear Energy Institute at CIEMAT carries out research projects and metallurgical examinations of failed components to gain some insight into the mechanisms of materials degradation with a direct impact on the life management of nuclear plants. (Author)

  2. Operational and materials aspects of aging management

    International Nuclear Information System (INIS)

    Muscara, J.; Vora, J.P.; Moyer, C.E.

    2005-01-01

    Understanding degradation phenomena and managing the detrimental effects of aging are important aspects of commercial nuclear power plant operations. Potential for materials degradation should be considered early in the design and development stages; during manufacturing, construction, and installation; and during all aspects of plant operation and maintenance. This would lead to increased reliability during plant operations, and would reduce the need for mitigating actions and unplanned maintenance. Thus, it is necessary to instill a culture at the technical, administrative, and management levels that continually asks, 'What happens with time?' The answer to this question is central to the continuous safe and economical operation of nuclear power plants. Based on the past 25 years of aging-related research at the U.S. Nuclear Regulatory Commission (NRC), the authors present an overview of the key elements of understanding and managing aging, and how they should be integrated for safe and economical power plant operation. The focus of this paper is hardware-oriented engineering and aging of materials. The paper discusses previous and ongoing NRC research studies on non-destructive examination and materials degradation that can be applied for proactive management of materials degradation and aging during plant operations. (author)

  3. Narayanaswamy's 1971 aging theory and material time

    Science.gov (United States)

    Dyre, Jeppe C.

    2015-09-01

    The Bochkov-Kuzovlev nonlinear fluctuation-dissipation theorem is used to derive Narayanaswamy's phenomenological theory of physical aging, in which this highly nonlinear phenomenon is described by a linear material-time convolution integral. A characteristic property of the Narayanaswamy aging description is material-time translational invariance, which is here taken as the basic assumption of the derivation. It is shown that only one possible definition of the material time obeys this invariance, namely, the square of the distance travelled from a configuration of the system far back in time. The paper concludes with suggestions for computer simulations that test for consequences of material-time translational invariance. One of these is the "unique-triangles property" according to which any three points on the system's path form a triangle such that two side lengths determine the third; this is equivalent to the well-known triangular relation for time-autocorrelation functions of aging spin glasses [L. F. Cugliandolo and J. Kurchan, J. Phys. A: Math. Gen. 27, 5749 (1994)]. The unique-triangles property implies a simple geometric interpretation of out-of-equilibrium time-autocorrelation functions, which extends to aging a previously proposed framework for such functions in equilibrium [J. C. Dyre, e-print arXiv:cond-mat/9712222 (1997)].

  4. Data base on structural materials aging properties

    International Nuclear Information System (INIS)

    Oland, C.B.

    1992-01-01

    The US Nuclear Regulatory Commission has initiated a Structural Aging Program at the Oak Ridge National Laboratory to identify potential structural safety issues related to continued service of nuclear power plants and to establish criteria for evaluating and resolving these issues. One of the tasks in this program focuses on the establishment of a Structural Materials Information Center where long-term and environment-dependent properties of concretes and other structural materials are being collected and assembled into a data base. These properties will be used to evaluate the current condition of critical structural components in nuclear power plants and to estimate the future performance of these materials during the continued service period

  5. Accelerated Aging of Polymer Composite Bridge Materials

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Nancy Margaret; Blackwood, Larry Gene; Torres, Lucinda Laine; Rodriguez, Julio Gallardo; Yoder, Timothy Scott

    1999-03-01

    Accelerated aging research on samples of composite material and candidate ultraviolet (UV) protective coatings is determining the effects of six environmental factors on material durability. Candidate fastener materials are being evaluated to determine corrosion rates and crevice corrosion effects at load-bearing joints. This work supports field testing of a 30-ft long, 18-ft wide polymer matrix composite (PMC) bridge at the Idaho National Engineering and Environmental Laboratory (INEEL). Durability results and sensor data from tests with live loads provide information required for determining the cost/benefit measures to use in life-cycle planning, determining a maintenance strategy, establishing applicable inspection techniques, and establishing guidelines, standards, and acceptance criteria for PMC bridges for use in the transportation infrastructure.

  6. Ageing in civil engineering materials and structures

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, Jean-Marc [SETEC TPI, Tour Gamma D 58, quai de la Rapee, 75583 Paris (France)

    2005-07-01

    SETEC TPI will address the 'Aging' topic of the Dijon Symposium by talking about: aging in civil engineering materials and structures, prevention of aging phenomena, in-operation monitoring of degradations related to aging and compensatory measures required to maintain a good safety level. Works as the Millau viaduct, the EdF skyscraper at La Defense - Paris, the renovation of the Grand Palais of Paris and special structures with Monaco's floating dam as well as the 'number 10' shaped gateway boat at Marseilles are illustrations for the issues discussed. The durability of civil engineering structures has become a major concern for designers. The Millau viaduct is designed for a service life of 120 years, and the Monaco dam for 100 years. Calculation rules have been evolving toward the incorporation of the concept of life cycle, for example, the Eurocodes 2 rules (reinforced concrete). The talk will expose the factors which are being taken into account to delay aging versus structure types. This part will be focused towards materials and corresponding regulations: - Reinforced concrete (coating of reinforcements, opening of cracks, choice of reinforcement types), BAEL and Eurocodes 2 rules; - Frame steel (protection, sacrificial anode), CM66 and Eurocodes 3 rules. New materials will also be mentioned: - Ultra high-performance fiber/concrete, with the example of CERACEM applied at Millau for the covering of the toll area barrier; - Titanium, which is starting to appear in the building trades, as for instance for the Beijing China Opera House shell. The second part of the talk will be devoted to a specific case namely, the 'number 10' shaped gateway bridge, a prestressed concrete structure immersed in the Port of Marseilles, which will be used to illustrate the aging phenomenon in a corrosive environment. We will focus on the types of inspection series performed by the Autonomous Port Authority of Marseilles to check the behavior of

  7. Microstructures and mechanical properties of aging materials

    International Nuclear Information System (INIS)

    Liaw, P.K.; Viswanathan, R.; Murty, K.L.; Simonen, E.P.; Frear, D.

    1993-01-01

    This book contains a collection of papers presented at the symposium on ''Microstructures and Mechanical Properties of Aging Materials,'' that was held in Chicago, IL. November 2-5, 1992 in conjunction with the Fall Meeting of The Minerals, Metals and Materials Society (TMS). The subjects of interest in the symposium included: (1) mechanisms of microstructural degradation, (2) effects of microstructural degradation on mechanical behavior, (3) development of life prediction methodology for in-service structural and electronic components, (4) experimental techniques to monitor degradation of microstructures and mechanical properties, and (5) effects of environment on microstructural degradation and mechanical properties. Individual papers have been processed separately for inclusion in the appropriate data bases

  8. Intelligent material systems - The dawn of a new materials age

    International Nuclear Information System (INIS)

    Rogers, C.A.

    1993-01-01

    The intelligent material system solution to such engineering problems as the design of a robotic arm borrows directly from biological analogs; materials that behave much as muscles do during contraction can be employed as induced strain actuators which work against the intrinsic structural impedance of the component. Unlike actual human arms, which are jointed, the intelligent structure may be a continuum. The adaptation of structural impedance may be regarded as the most fundamental and consequential concept in the field of intelligent material systems

  9. Materialism across the lifespan : An age-period-cohort analysis

    NARCIS (Netherlands)

    Jaspers, Esther; Pieters, Rik

    This research examined the development of materialism across the lifespan. Two initial studies revealed that: 1) lay beliefs were that materialism declines with age; and 2) previous research findings also implied a modest, negative relationship between age and materialism. Yet, previous research has

  10. Materials science in the information age

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, L.H.; Glotzer, S.C.; Hall, D.E.; Roosen, A.R.; Warren, J.A.

    1996-12-31

    The explosive growth of the Internet and the World Wide Web is revolutionizing society be, making information accessible in new ways to People in all corners of the world. In scientific research, these advances in information technology have led to new methods of collaboration that overcome geographic limitations and allow researchers to exchange information in ways that were not previously possible. Materials researchers in particular now easily work with each other in remote collaborations, sharing videos, sound, graphics, and text with colleagues on the World Wide Web. Moreover, recent gains in computing power and corresponding reductions in cost have led to the widespread use of computational techniques to solve materials research problems, allowing researchers to predict materials properties and behavior over the entire range of length scales of interest, from atomic interactions to bulk materials properties. New {open_quotes}virtual{close_quotes} organizations have been created in the US to provide an infrastructure and support to researchers who are using new communication and computational tools in a variety of disciplines. We will describe the recent advances in information technology that are driving the revolution in materials research in particular, and discuss how virtual, electronically-connected organizations that bring together materials researchers with diverse talents in international, multilateral collaborations will change the paradigm of science research beyond the year 2000. 14 refs.

  11. [Research on the aging of all-ceramics restoration materials].

    Science.gov (United States)

    Zhang, Dongjiao; Chen, Xinmin

    2011-10-01

    All-ceramic crowns and bridges have been widely used for dental restorations owing to their excellent functionality, aesthetics and biocompatibility. However, the premature clinical failure of all-ceramic crowns and bridges may easily occur when they are subjected to the complex environment of oral cavity. In the oral environment, all-ceramic materials are prone to aging. Aging can lead all-ceramic materials to change color, to lower bending strength, and to reduce anti-fracture toughness. There are many factors affecting the aging of the all-ceramic materials, for example, the grain size, the type of stabilizer, the residual stress and the water environment. In order to analyze the aging behavior, to optimize the design of all-ceramic crowns and bridges, and to evaluate the reliability and durability, we review in this paper recent research progress of aging behavior for all-ceramics restoration materials.

  12. Materials aging: first predictive modeling of iron under irradiation

    International Nuclear Information System (INIS)

    Anon.

    2005-01-01

    Researchers from the CEA-Bruyeres-le-Chatel have been able to quantitatively foresee for the very first time the evolution of irradiation defects inside a structural material. Their results, obtained with iron, will contribute to better understand the aging of the materials of today's nuclear power plants and of future nuclear systems. Short paper. (J.S.)

  13. Narayanaswamy’s 1971 aging theory and material time

    DEFF Research Database (Denmark)

    Dyre, Jeppe C.

    2015-01-01

    The Bochkov-Kuzovlev nonlinear fluctuation-dissipation theorem is used to derive Narayanaswamy’s phenomenological theory of physical aging, in which this highly nonlinear phenomenon is described by a linear material-time convolution integral. A characteristic property of the Narayanaswamy aging...... description is material-time translational invariance, which is here taken as the basic assumption of the derivation. It is shown that only one possible definition of the material time obeys this invariance, namely, the square of the distance travelled from a configuration of the system far back in time...

  14. In-service irradiated and aged material evaluations

    International Nuclear Information System (INIS)

    Haggag, F.M.; Nanstad, R.K.; Alexander, D.J.

    1995-01-01

    The objective of this task is to provide a direct assessment of actual material properties in irradiated components of nuclear reactors, including the effects of irradiation and aging. Four activities are currently in progress: (1) establishing a machining capability for contaminated or activated materials by completing procurement and installation of a computer-based milling machine in a hot cell; (2) machining and testing specimens from cladding materials removed from the Gundremmingen reactor to establish their fracture properties; (3) preparing an interpretive report on the effects of neutron irradiation on cladding; and (4) continuing the evaluation of long-term aging of austenitic structural stainless steel weld metal by metallurgically examining and testing specimens aged at 288 and 343 degrees C and reporting the results, as well as by continuing the aging of the stainless steel cladding toward a total time of 50,000 h

  15. Aging mechanisms in amorphous phase-change materials.

    Science.gov (United States)

    Raty, Jean Yves; Zhang, Wei; Luckas, Jennifer; Chen, Chao; Mazzarello, Riccardo; Bichara, Christophe; Wuttig, Matthias

    2015-06-24

    Aging is a ubiquitous phenomenon in glasses. In the case of phase-change materials, it leads to a drift in the electrical resistance, which hinders the development of ultrahigh density storage devices. Here we elucidate the aging process in amorphous GeTe, a prototypical phase-change material, by advanced numerical simulations, photothermal deflection spectroscopy and impedance spectroscopy experiments. We show that aging is accompanied by a progressive change of the local chemical order towards the crystalline one. Yet, the glass evolves towards a covalent amorphous network with increasing Peierls distortion, whose structural and electronic properties drift away from those of the resonantly bonded crystal. This behaviour sets phase-change materials apart from conventional glass-forming systems, which display the same local structure and bonding in both phases.

  16. Case for non-material specific thermal aging

    International Nuclear Information System (INIS)

    Bessey, R.L.

    1982-01-01

    The state-of-the-art model for accelerated thermal aging of components prior to seismic testing is the Arrhenius Model. The most pertinent independent variable in the equation is the minimum activation energy constant characterizing the component aging. With minor exceptions, existing measured values of the activation energy constant are inadequate as input to the model where a material specific aging acceleration factor is to be determined, for reasons described. The model itself is not very accurate. A case is made for a statistically justified minimum activation energy constant which is not material specific. The advantages of this are assessed. The major advantage is that this would provide the industry with a practical and uniform aging method that is consistent with the accuracy of the model

  17. Narayanaswamy’s 1971 aging theory and material time

    International Nuclear Information System (INIS)

    Dyre, Jeppe C.

    2015-01-01

    The Bochkov-Kuzovlev nonlinear fluctuation-dissipation theorem is used to derive Narayanaswamy’s phenomenological theory of physical aging, in which this highly nonlinear phenomenon is described by a linear material-time convolution integral. A characteristic property of the Narayanaswamy aging description is material-time translational invariance, which is here taken as the basic assumption of the derivation. It is shown that only one possible definition of the material time obeys this invariance, namely, the square of the distance travelled from a configuration of the system far back in time. The paper concludes with suggestions for computer simulations that test for consequences of material-time translational invariance. One of these is the “unique-triangles property” according to which any three points on the system’s path form a triangle such that two side lengths determine the third; this is equivalent to the well-known triangular relation for time-autocorrelation functions of aging spin glasses [L. F. Cugliandolo and J. Kurchan, J. Phys. A: Math. Gen. 27, 5749 (1994)]. The unique-triangles property implies a simple geometric interpretation of out-of-equilibrium time-autocorrelation functions, which extends to aging a previously proposed framework for such functions in equilibrium [J. C. Dyre, e-print arXiv:cond-mat/9712222 (1997)

  18. Materialism and the future of aging in America.

    Science.gov (United States)

    Almeder, R F

    1983-01-01

    In Growing Old in America, David Fischer argues that colonial America witnessed a sudden and revolutionary shift in social attitude from gerontophilia to gerontophobia. It is argued here that the shift can be explained as the necessary result of an emerging materialism which came to dominate mercantile America. It is shown how philosophical materialism requires an attitude of denigration toward aging and the elderly, and that the future of our collective attitude toward the elderly is wedded philosophically to the future success or failure of philosophical materialism. It is also suggested that the future of materialism in America looks dim and that there will emerge a strong philosophical base adequate for reforming ethical attitudes and engendering a much more favorable attitude toward the elderly in general. It is suggested that positive or negative attitudes toward aging and the elderly are rooted in unconscious commitments to non-materialistic (dualistic) or materialistic views on the nature of man. The two basically different views on the nature of man beget the two basically different views and attitudes toward aging and the elderly. Which attitude is right is a function of which philosophical view is correct and the paper closes with some evidence that materialism is on the wane.

  19. A data base for aging of structural materials

    International Nuclear Information System (INIS)

    Oland, C.B.; Naus, D.J.; Jerath, S.

    1993-01-01

    The U.S. Nuclear Regulatory Commission (USNRC) initiated a Structural Aging (SAG) Program at the Oak Ridge National Laboratory (ORNL). The objective of the program is to provide assistance in identifying potential structural safety issues and to establish acceptance criteria for use in nuclear power plant evaluations for continued service. One of the main parts of the program focuses on the development of a Structural Materials Information Center where long-term and environment-dependent material properties are being collected and assembled into a data base. This data base is presented in two complementary formats. The Structural Materials Handbook is an expandable, hard-copy reference document that contains the complete data base for each material. The Structural Materials Electronic Data Base is accessible using an IBM-compatible personal computer. This paper presents an overview of the Structural Materials Information Center and briefly describes the features of the handbook and the electronic data base. In addition, a proposed method for using the data base to establish current property values for materials in existing concrete structures and to estimate the future performance of these materials is also presented. (author)

  20. A data base for aging of structural materials

    International Nuclear Information System (INIS)

    Oland, C.B.; Naus, D.J.; Jerath, S.

    1993-01-01

    USNRC initiated a Structural Aging (SAG) Program ORNL. The objective of the program is to provide assistance in identifying potential structural safety issues and to establish acceptance criteria for use in nuclear power plant evaluations for continued service. One main part focuses on the development of a Structural Materials Information Center where long-term and environment-dependent material properties are being collected and assembled into a data base. This data base is presented in two complementary formats. The Structural Materials Handbook is an expandable, hard-copy reference document that contains the complete data base for each material. The Structural Materials Electronic Data Base is accessible using an IBM-compatible personal computer. This paper presents an overview of the Structural Materials Information Center and briefly describes the features of the handbook and the electronic data base. In addition, a proposed method for using the data base to establish current property values for materials in existing concrete structures and to estimate the future performance of these materials is also presented

  1. First Exploratory Study on the Ageing of Rammed Earth Material

    Science.gov (United States)

    Bui, Quoc-Bao; Morel, Jean-Claude

    2014-01-01

    Rammed earth (RE) is attracting renewed interest throughout the world thanks to its “green” characteristics in the context of sustainable building. In this study, the ageing effects on RE material are studied on the walls which have been constructed and exposed for 22 years to natural weathering. First, mechanical characteristics of the “old” walls were determined by two approaches: in-situ dynamic measurements on the walls; laboratory tests on specimens which had been cut from the walls. Then, the walls’ soil was recycled and reused for manufacturing of new specimens which represented the initial state. Comparison between the compressive strength, the Young modulus of the walls after 22 years on site and that of the initial state enables to assess the ageing of the studied walls. PMID:28787920

  2. Proactive materials aging management and multi-layered maintenance

    International Nuclear Information System (INIS)

    Shoji, Tetsuo

    2009-01-01

    Long term operation of NPP has been receiving a great concern based upon the plant operation experiences and progressive improvement in countermeasures and mitigations. At the same time of this LTO movement, proactive materials aging management is also receiving a great concern to realize the LTO in NPP. Recent PMDM activities in Japan as well as some international one are reviewed and a necessity of an international cooperation is emphasized in relation to reliable maintenance performance connected from the top of the organization to operators and maintenance engineers at plant sites. (author)

  3. Doing Age in a Digitized World—A Material Praxeology of Aging With Technology

    Directory of Open Access Journals (Sweden)

    Anna Wanka

    2018-04-01

    Full Text Available Digital technologies have gained vast relevance in postmodern societies and digital infrastructures are substantially integrated into the everyday lives of older people. This digitization is reframing the norms and practices of later life as well as the social construct of age itself. Despite the increasing amount of studies in the field of aging and technologies, it still lacks theorizing. This paper addresses this deficit, suggesting that the study of aging and technologies could profit from a comprehensive integration of theories from the sociology of aging, critical gerontology, and science-and-technology studies. We aim to make a theoretical contribution to this issue, asking: how is age being done in a digitized world? Applying a praxeological approach to aging and technologies, we firstly examine how theoretical and empirical work has constructed aging with technologies so far and identify its shortcomings. Some of this work so far lacks a proper consideration of social inequalities within these processes, whereas other studies lack a thorough consideration of materialities. Secondly, in an attempt to equally “praxeologize” and “materialize” the study of aging and technologies we develop a theoretical model that aims to overcome these shortcomings. In what we frame as a material praxeology of aging with technology, we are concerned with how age is being done through discursive formations, set into practice through social and material practices and involved in the (reproduction of social inequalities. Enriching a Bordieuan terminology of social fields with notions of non-human agency, this praxeology is founded on three assumptions: (1 Social fields constitute the contexts in which age as a social phenomenon is being done with and through technologies (2 Human and non-human agents are equally involved in this process (3 The actions of the involved agents emerge from an agency distributed among them, and are structured through the

  4. Simulated Aging of Spacecraft External Materials on Orbit

    Science.gov (United States)

    Khatipov, S.

    Moscow State Engineering Physics Institute (MIFI), in cooperation with Air Force Research Laboratory's Satellite Assessment Center (SatAC), the European Office of Aerospace Research and Development (EOARD), and the International Science and Technology Center (ISTC), has developed a database describing the changes in optical properties of materials used on the external surfaces of spacecraft due to space environmental factors. The database includes data acquired from tests completed under contract with the ISTC and EOARD, as well as from previous Russian materials studies conducted within the last 30 years. The space environmental factors studied are for those found in Low Earth Orbits (LEO) and Geosynchronous orbits (GEO), including electron irradiation at 50, 100, and 200 keV, proton irradiation at 50, 150, 300, and 500 keV, and ultraviolet irradiation equivalent to 1 sun-year. The material characteristics investigated were solar absorption (aS), spectral reflectance (rl), solar reflectance (rS), emissivity (e), spectral transmission coefficient (Tl), solar transmittance (TS), optical density (D), relative optical density (D/x), Bi-directional Reflectance Distribution Function (BRDF), and change of appearance and color in the visible wavelengths. The materials tested in the project were thermal control coatings (paints), multilayer insulation (films), and solar cells. The ability to predict changes in optical properties of spacecraft materials is important to increase the fidelity of space observation tools, better understand observation of space objects, and increase the longevity of spacecraft. The end goal of our project is to build semi-empirical mathematical models to predict the long-term effects of space aging as a function of time and orbit.

  5. Electrochemical migration technique to accelerate ageing of cementitious materials

    Directory of Open Access Journals (Sweden)

    Abbas Z.

    2013-07-01

    Full Text Available Durability assessment of concrete structures for constructions in nuclear waste repositories requires long term service life predictions. As deposition of low and intermediate level radioactive waste (LILW takes up to 100 000 years, it is necessary to analyze the service life of cementitious materials in this time perspective. Using acceleration methods producing aged specimens would decrease the need of extrapolating short term data sets. Laboratory methods are therefore, needed for accelerating the ageing process without making any influencing distortion in the properties of the materials. This paper presents an electro-chemical migration method to increase the rate of calcium leaching from cementitious specimens. This method is developed based on the fact that major long term deterioration process of hardened cement paste in concrete structures for deposition of LILW is due to slow diffusion of calcium ions. In this method the cementitious specimen is placed in an electrochemical cell as a porous path way through which ions can migrate at a rate far higher than diffusion process. The electrical field is applied to the cell in a way to accelerate the ion migration without making destructions in the specimen’s micro and macroscopic properties. The anolyte and catholyte solutions are designed favoring dissolution of calcium hydroxide and compensating for the leached calcium ions with another ion like lithium.

  6. Electrochemical migration technique to accelerate ageing of cementitious materials

    Science.gov (United States)

    Babaahmadi, A.; Tang, L.; Abbas, Z.

    2013-07-01

    Durability assessment of concrete structures for constructions in nuclear waste repositories requires long term service life predictions. As deposition of low and intermediate level radioactive waste (LILW) takes up to 100 000 years, it is necessary to analyze the service life of cementitious materials in this time perspective. Using acceleration methods producing aged specimens would decrease the need of extrapolating short term data sets. Laboratory methods are therefore, needed for accelerating the ageing process without making any influencing distortion in the properties of the materials. This paper presents an electro-chemical migration method to increase the rate of calcium leaching from cementitious specimens. This method is developed based on the fact that major long term deterioration process of hardened cement paste in concrete structures for deposition of LILW is due to slow diffusion of calcium ions. In this method the cementitious specimen is placed in an electrochemical cell as a porous path way through which ions can migrate at a rate far higher than diffusion process. The electrical field is applied to the cell in a way to accelerate the ion migration without making destructions in the specimen's micro and macroscopic properties. The anolyte and catholyte solutions are designed favoring dissolution of calcium hydroxide and compensating for the leached calcium ions with another ion like lithium.

  7. Materials compatibility and aging for flux and cleaner combinations

    Energy Technology Data Exchange (ETDEWEB)

    Archuleta, Kim M. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Piatt, Rochelle [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-01-01

    A materials study of high reliability electronics cleaning is presented here. In Phase 1, mixed type substrates underwent a condensed contaminants application to view a worst- case scenario for unremoved flux with cleaning agent residue for parts in a silicone oil filled environment. In Phase 2, fluxes applied to copper coupons and to printed wiring boards underwent gentle cleaning then accelerated aging in air at 65% humidity and 30 O C. Both sets were aged for 4 weeks. Contaminants were no-clean (ORL0), water soluble (ORH1 liquid and ORH0 paste), and rosin (RMA; ROL0) fluxes. Defluxing agents were water, solvents, and engineered aqueous defluxers. In the first phase, coupons had flux applied and heated, then were placed in vials of oil with a small amount of cleaning agent and additional coupons. In the second phase, pairs of copper coupons and PWB were hand soldered by application of each flux, using tin-lead solder in a strip across the coupon or a set of test components on the PWB. One of each pair was cleaned in each cleaning agent, the first with a typical clean, and the second with a brief clean. Ionic contamination residue was measured before accelerated aging. After aging, substrates were removed and a visual record of coupon damage made, from which a subjective rank was applied for comparison between the various flux and defluxer combinations; more corrosion equated to higher rank. The ORH1 water soluble flux resulted in the highest ranking in both phases, the RMA flux the least. For the first phase, in which flux and defluxer remained on coupons, the aqueous defluxers led to worse corrosion. The vapor phase cleaning agents resulted in the highest ranking in the second phase, in which there was no physical cleaning. Further study of cleaning and rinsing parameters will be required.

  8. Impact of aging and material structure on CANDU plant performance

    International Nuclear Information System (INIS)

    Nadeau, E.; Ballyk, J.; Ghalavand, N.

    2011-01-01

    In-service behaviour of pressure tubes is a key factor in the assessment of safety margins during plant operation. Pressure tube deformation (diametral expansion) affects fuel bundle dry out characteristics resulting in reduced margin to trip for some events. Pressure tube aging mechanisms also erode design margins on fuel channels or interfacing reactor components. The degradation mechanisms of interest are primarily deformation, loss of fracture resistance and hydrogen ingress. CANDU (CANada Deuterium Uranium, a registered trademark of the Atomic Energy of Canada Limited used under exclusive licence by Candu Energy Inc.) owners and operators need to maximize plant capacity factor and meet or exceed the reactor design life targets while maintaining safety margins. The degradation of pressure tube material and geometry are characterized through a program of inspection, material surveillance and assessment and need to be managed to optimize plant performance. Candu is improving pressure tubes installed in new build and life extension projects. Improvements include changes designed to reduce or mitigate the impact of pressure tube elongation and diametral expansion rates, improvement of pressure tube fracture properties, and reduction of the implications of hydrogen ingress. In addition, Candu provides an extensive array of engineering services designed to assess the condition of pressure tubes and address the impact of pressure tube degradation on safety margins and plant performance. These services include periodic and in-service inspection and material surveillance of pressure tubes and deterministic and probabilistic assessment of pressure tube fitness for service to applicable standards. Activities designed to mitigate the impact of pressure tube deformation on safety margins include steam generator cleaning, which improves trip margins, and trip design assessment to optimize reactor trip set points restoring safety and operating margins. This paper provides an

  9. Impact of aging and material structure on CANDU plant performance

    Energy Technology Data Exchange (ETDEWEB)

    Nadeau, E.; Ballyk, J.; Ghalavand, N. [Candu Energy Inc., Mississauga, Ontario (Canada)

    2011-07-01

    In-service behaviour of pressure tubes is a key factor in the assessment of safety margins during plant operation. Pressure tube deformation (diametral expansion) affects fuel bundle dry out characteristics resulting in reduced margin to trip for some events. Pressure tube aging mechanisms also erode design margins on fuel channels or interfacing reactor components. The degradation mechanisms of interest are primarily deformation, loss of fracture resistance and hydrogen ingress. CANDU (CANada Deuterium Uranium, a registered trademark of the Atomic Energy of Canada Limited used under exclusive licence by Candu Energy Inc.) owners and operators need to maximize plant capacity factor and meet or exceed the reactor design life targets while maintaining safety margins. The degradation of pressure tube material and geometry are characterized through a program of inspection, material surveillance and assessment and need to be managed to optimize plant performance. Candu is improving pressure tubes installed in new build and life extension projects. Improvements include changes designed to reduce or mitigate the impact of pressure tube elongation and diametral expansion rates, improvement of pressure tube fracture properties, and reduction of the implications of hydrogen ingress. In addition, Candu provides an extensive array of engineering services designed to assess the condition of pressure tubes and address the impact of pressure tube degradation on safety margins and plant performance. These services include periodic and in-service inspection and material surveillance of pressure tubes and deterministic and probabilistic assessment of pressure tube fitness for service to applicable standards. Activities designed to mitigate the impact of pressure tube deformation on safety margins include steam generator cleaning, which improves trip margins, and trip design assessment to optimize reactor trip set points restoring safety and operating margins. This paper provides an

  10. Materials ageing degradation programme in japan and proactive ageing management in NPP

    International Nuclear Information System (INIS)

    Shoji, T.

    2013-01-01

    Predictive and preventive maintenance technologies are increasingly of importance for the long term operation (LTO) of Light Water Reactor (LWR) plants. In order for the realization LTO to be successful, it is essential that aging degradation phenomena should be properly managed by using adequate maintenance programs based on foreseeing the aging phenomena and evaluating their rates of development, where Nuclear Power Plants can be continued to operate beyond the original design life depending upon the regulatory authority rules. In combination with Periodic Safety Review (PSR) and adequate maintenance program, a plant life can be extended to 60 years or more. Plant Life Management (PLiM) is based upon various maintenance program as well as systematic safety review updated based upon the state of the art of science and technology. One of the potential life time limiting issue would be materials ageing degradation and therefore an extensive efforts have been paid world-widely. In 2007, NISA launched a national program on Enhanced Ageing Management Program and 4 nationwide clusters were formed to carry out the national program where materials ageing degradation was one of the major topics. In addition to these degradation modes, one important activities in this program is proactive materials degradation management directed by the author which is a kind of the extension program of NRC PMDA program based upon more fundamental approach by a systematic elicitation by the experts nominated from all over the world. NISA program can be divided into two phases, one is from fiscal years (FY) 2006 - 2010 and the other FY 2011. Later phase is focusing more on System Safety due to Fukushima NPP accident. The main objectives of the Phase I is to evaluate potential and complex degradation phenomena and their mechanisms in order to identify future risks of component aging in nuclear power plants. The following items are of particular concern in this phase: (a) investigation of

  11. FY 2017 – Thermal Aging Effects on Advanced Structural Materials

    Energy Technology Data Exchange (ETDEWEB)

    Li, Meimei [Argonne National Lab. (ANL), Argonne, IL (United States); Natesan, K [Argonne National Lab. (ANL), Argonne, IL (United States); Chen, Wei-Ying [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-08-01

    This report provides an update on the evaluation of the effect of thermal aging on tensile properties of existing laboratory-sized heats of Alloy 709 austenitic stainless steel and the completion of effort on the thermal aging effect on the tensile properties of optimized G92 ferritic-martensitic steel. The report is a Level 3 deliverable in FY17 (M3AT-17AN1602081), under the Work Package AT-17AN160208, “Advanced Alloy Testing - ANL” performed by the Argonne National Laboratory (ANL), as part of the Advanced Reactor Technologies Program.

  12. Environmental Effects on ISS Materials Aging (1998 to 2008)

    Science.gov (United States)

    Alred, John; Dasgupta, Rajib; Koontz, Steve; Soares, Carlos; Golden, John

    2009-01-01

    The performance of ISS spacecraft materials and systems on prolonged exposure to the low- Earth orbit (LEO) space flight are reported in this paper. In-flight data, flight crew observations, and the results of ground-based test and analysis directly supporting programmatic and operational decision-making are described. The space flight environments definitions (both natural and induced) used for ISS design, material selection, and verification testing are shown, in most cases, to be more severe than the actual flight environment accounting, in part, for the outstanding performance of ISS as a long mission duration spacecraft. No significant ISS material or system failures have been attributed to spacecraft-environments interactions. Nonetheless, ISS materials and systems performance data is contributing to our understanding of spacecraft material interactions with the spaceflight environment so as to reduce cost and risk for future spaceflight projects and programs. Orbital inclination (51.6 deg) and altitude (nominally near 360 km) determine the set of natural environment factors affecting the functional life of materials and systems on ISS. ISS operates in an electrically conducting environment (the F2 region of Earth s ionosphere) with well-defined fluxes of atomic oxygen, other charged and neutral ionospheric plasma species, solar UV, VUV, and x-ray radiation as well as galactic cosmic rays, trapped radiation, and solar cosmic rays. The LEO micrometeoroid and orbital debris environment is an especially important determinant of spacecraft design and operations. The magnitude of several environmental factors varies dramatically with latitude and longitude as ISS orbits the Earth. The high latitude orbital environment also exposes ISS to higher fluences of trapped energetic electrons, auroral electrons, solar cosmic rays, and galactic cosmic rays than would be the case in lower inclination orbits, largely as a result of the overall shape and magnitude of the

  13. Ageing of structural materials in tokamaks: TEXTOR liner study

    Science.gov (United States)

    Weckmann, A.; Petersson, P.; Rubel, M.; Fortuna-Zaleśna, E.; Zielinski, W.; Romelczyk-Baishya, B.; Grigore, E.; Ruset, C.; Kreter, A.

    2017-12-01

    After the final shut-down of the tokamak TEXTOR, all of its machine parts became accessible for comprehensive studies. This unique opportunity enabled the study of the Inconel 625 liner by a wide range of methods. The aim was to evaluate eventual alteration of surface and bulk characteristics from recessed wall elements that may influence the machine performance. The surface was covered with stratified layers consisting mainly of boron, carbon, oxygen, and in some cases also silicon. Wall conditioning and limiter materials hence predominantly define deposition on the liner. Deposited layers on recessed wall elements reach micrometre thickness within decades, peel off and may contribute to the dust inventory in tokamaks. Deuterium content was about 4,7 at% on average most probably due to wall conditioning with deuterated gas, and very low concentration in the Inconel substrate. Inconel 625 retained its mechanical strength despite 26 years of cyclic heating, stresses and particle bombardment.

  14. Materialism across the life span: An age-period-cohort analysis.

    Science.gov (United States)

    Jaspers, Esther D T; Pieters, Rik G M

    2016-09-01

    This research examined the development of materialism across the life span. Two initial studies revealed that (a) lay beliefs were that materialism declines with age and (b) previous research findings also implied a modest, negative relationship between age and materialism. Yet, previous research has considered age only as a linear control variable, thereby precluding the possibility of more intricate relationships between age and materialism. Moreover, prior studies have relied on cross-sectional data and thus confound age and cohort effects. To improve on this, the main study used longitudinal data from 8 waves spanning 9 years of over 4,200 individuals (16 to 90 years) to examine age effects on materialism while controlling for cohort and period effects. Using a multivariate multilevel latent growth model, it found that materialism followed a curvilinear trajectory across the life span, with the lowest levels at middle age and higher levels before and after that. Thus, in contrast to lay beliefs, materialism increased in older age. Moreover, age effects on materialism differed markedly between 3 core themes of materialism: acquisition centrality, possession-defined success, and acquisition as the pursuit of happiness. In particular, acquisition centrality and possession-defined success were higher at younger and older age. Independent of these age effects, older birth cohorts were oriented more toward possession-defined success, whereas younger birth cohorts were oriented more toward acquisition centrality. The economic downturn since 2008 led to a decrease in acquisition as the pursuit of happiness and in desires for personal growth, but to an increase in desires for achievement. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  15. Assessment of Aging of Cork and TISAF Materials in the SAFKEG 3940A Package in KAMS

    International Nuclear Information System (INIS)

    Vormelker, P.R.

    2003-01-01

    This report provides an assessment of the potential for aging and degradation of the resin-bonded cork and the Thermal-Insulating, Shock-Absorbing Foam materials that are components of the SAFKEG 3940A package. This package may be used for interim storage of plutonium materials in the Savannah River Site K-Area Materials Storage

  16. Evaluation of Proactive Management Issues Associated with Materials Aging in Light Water Reactors

    International Nuclear Information System (INIS)

    Shoji, T.; Takeda, Y.; Kuniya, J.

    2012-01-01

    A Proactive Materials Degradation Management (PMDM) project has been carried out at the Fracture Research Institute (FRI), Tohoku University for 4 years, as a part of a Nuclear Industries Safety Agency (NISA) project that was formed in 2007 to define an Aging Management Program that addresses unexpected structural material failures in Light Water Reactors (LWRs). Such a program required, therefore, the development of a life prediction capability for specific combinations of degradation modes, structural materials, and reactor components. In this paper, the research subjects needed to predict quantitatively aging degradation phenomena in LWR structural materials are introduced. (author)

  17. Feasibility Study for the Development of Plutonium Reference Materials for Age Dating in Nuclear Forensics

    International Nuclear Information System (INIS)

    Sturm, M.; Richter, S.; Aregbe, Y.; Wellum, R.; Altzitzoglou, T.; Verbruggen, A.; Mayer, K.; Prohaska, T.

    2010-01-01

    Isotopic reference materials certified for the age of nuclear material (uranium, plutonium) are needed in the fields of nuclear forensics and environmental measurements. Therefore a feasibility study for the development of plutonium reference materials for age dating has been started recently at the Institute for Reference Materials and Measurements (EC-JRC-IRMM). The ''age'' of the material is defined as the time that has passed since the last chemical separation of the mother and daughter isotopes (e.g. 241 Pu and 241 Am). Assuming that the separation has been complete and all the daughter isotopes have been removed from the original material during this last separation, the age of the material can be determined by measuring the ratio of daughter and mother radio-nuclides, e.g. 241 Am/ 241 Pu. At a given time after the last separation and depending on the half lives of the radio-nuclides involved, a certain amount of the daughter radionuclide(s) will be present. For the determination of the unknown age of a material different ''clocks'' can be used; ''clocks'' are pairs of mother and daughter radio-nuclides, such as 241 Am/ 241 Pu, 238 Pu/ 234 U, 239 Pu/ 235 U, 240 Pu/ 236 U, and possibly 242 Pu/ 238 U. For the age estimation of a real sample, such as material seized in nuclear forensics investigations or dust samples in environmental measurements, it is advisable to use more than one clock in order to ensure the reliability of the results and to exclude the possibility that the sample under question is a mixture of two or more materials. Consequently, a future reference material certified for separation date should ideally be certified for more than one ''clock'' or several reference materials for different ''clocks'' should be developed. The first step of this study is to verify the known separation dates of different plutonium materials of different ages and isotopic compositions by measuring the mother ( 238 Pu, 239 Pu, 240 Pu, 241 Pu, 242 Pu) and daughter

  18. Suitability of asthma education materials for school-age children: Implications for health literacy.

    Science.gov (United States)

    Tzeng, Yu-Fen; Gau, Bih-Shya

    2018-03-01

    To investigate the suitability of asthma education materials for school-age children with asthma and elucidate how these children used their health-literacy abilities to identify whether the materials can be accepted, comprehended and applied. Effective asthma self-management education is influenced by the suitability of materials and an individual's health literacy. A mixed-method research design was developed using quantitative and qualitative surveys. The suitability of the materials was assessed on the basis of the Chinese version of the Suitability Assessment of Materials by five experts. In addition, five school-age children (age: 8-12 years) were recruited and interviewed. In total, 25 pieces of asthma education material for children were collected. On the basis of their type, the materials were categorised as nine brochures, 11 leaflets and five videos. Of the 25 materials, 17 were rated as superior materials, whereas eight were rated as adequate materials. The suitability scores of the video-based materials were significantly higher than those of the brochures and leaflets (p = .006). One print material was considered to have a reading level suitable for fifth-grade or younger children, whereas the remaining materials were considered suitable for sixth-grade or older children. The following six health-literacy domains were identified: recognising asthma through body knowledge, posing reflective questions, identifying self-care difficulties, receiving adult guidance, learning with enjoyment and addressing learning requirements. The video-based materials had integrated content and were appealing to children. Cartoon animations, interactive computer games, and skill demonstrations may enhance learning stimulation and motivation and increase learning effects in children. The present results may help healthcare providers to understand children's capacities to manage their disease, effectively address children's requirements and function as a key resource for

  19. Aging predictions in nuclear power plants: Crosslinked polyolefin and EPR cable insulation materials

    International Nuclear Information System (INIS)

    Gillen, K.T.; Clough, R.L.

    1991-06-01

    In two earlier reports, we derived a time-temperature-dose rate superposition methodology, which, when applicable, can be used to predict cable degradation versus dose rate, temperature and exposure time. This methodology results in long-term predictive capabilities at the low dose rates appropriate to ambient nuclear power plant aging environments. The methodology was successfully applied to numerous important cable materials used in nuclear applications and the extrapolated predictions were verified by comparisons with long-term (7 to 12 year) results for similar or identical materials aged in nuclear environments. In this report, we test the methodology on three crosslinked polyolefin (CLPO) and two ethylene propylene rubber (EPR) cable insulation materials. The methodology applies to one of the CLPO materials and one of the EPR materials, allowing predictions to be made for these materials under low dose-rate, low temperature conditions. For the other materials, it is determined that, at low temperatures, a decrease in temperature at a constant radiation dose rate leads to an increase in the degradation rate for the mechanical properties. Since these results contradict the fundamental assumption underlying time-temperature-dose rate superposition, this methodology cannot be applied to such data. As indicated in the earlier reports, such anomalous results might be expected when attempting to model data taken across the crystalline melting region of semicrystalline materials. Nonetheless, the existing experimental evidence suggests that these CLPO and EPR materials have substantial aging endurance for typical reactor conditions. 28 refs., 26 figs., 3 tabs

  20. Translucency changes of direct esthetic restorative materials after curing, aging and treatment

    Directory of Open Access Journals (Sweden)

    Yong-Keun Lee

    2016-11-01

    Full Text Available The purpose of this article was to review the changes in translucency of direct esthetic restorative materials after curing, aging and treatment. As a criterion for the evaluation of clinical translucency changes, visual perceptibility threshold in translucency parameter difference (ΔTP of 2 was used. Translucency changes after curing were perceivable depending on experimental methods and products (largest ΔTP in resin composites = 15.9. Translucency changes after aging were reported as either relatively stable or showed perceivable changes by aging protocols (largest ΔTP in resin composites = -3.8. Translucency changes after curing, aging and treatment were perceivable in several products and experimental methods. Therefore, shade matching of direct esthetic materials should be performed considering these instabilities of translucency in direct esthetic materials.

  1. Statistical models for thermal ageing of steel materials in nuclear power plants

    International Nuclear Information System (INIS)

    Persoz, M.

    1996-01-01

    Some category of steel materials in nuclear power plants may be subjected to thermal ageing, whose extent depends on the steel chemical composition and the ageing parameters, i.e. temperature and duration. This ageing affects the 'impact strength' of the materials, which is a mechanical property. In order to assess the residual lifetime of these components, a probabilistic study has been launched, which takes into account the scatter over the input parameters of the mechanical model. Predictive formulae for estimating the impact strength of aged materials are important input data of the model. A data base has been created with impact strength results obtained from an ageing program in laboratory and statistical treatments have been undertaken. Two kinds of model have been developed, with non linear regression methods (PROC NLIN, available in SAS/STAT). The first one, using a hyperbolic tangent function, is partly based on physical considerations, and the second one, of an exponential type, is purely statistically built. The difficulties consist in selecting the significant parameters and attributing initial values to the coefficients, which is a requirement of the NLIN procedure. This global statistical analysis has led to general models that are unction of the chemical variables and the ageing parameters. These models are as precise (if not more) as local models that had been developed earlier for some specific values of ageing temperature and ageing duration. This paper describes the data and the methodology used to build the models and analyses the results given by the SAS system. (author)

  2. 230Th-234U Model-Ages of Some Uranium Standard Reference Materials

    International Nuclear Information System (INIS)

    Williams, R.W.; Gaffney, A.M.; Kristo, M.J.; Hutcheon, I.D.

    2009-01-01

    The 'age' of a sample of uranium is an important aspect of a nuclear forensic investigation and of the attribution of the material to its source. To the extent that the sample obeys the standard rules of radiochronometry, then the production ages of even very recent material can be determined using the 230 Th- 234 U chronometer. These standard rules may be summarized as (a) the daughter/parent ratio at time=zero must be known, and (b) there has been no daughter/parent fractionation since production. For most samples of uranium, the 'ages' determined using this chronometer are semantically 'model-ages' because (a) some assumption of the initial 230 Th content in the sample is required and (b) closed-system behavior is assumed. The uranium standard reference materials originally prepared and distributed by the former US National Bureau of Standards and now distributed by New Brunswick Laboratory as certified reference materials (NBS SRM = NBL CRM) are good candidates for samples where both rules are met. The U isotopic standards have known purification and production dates, and closed-system behavior in the solid form (U 3 O 8 ) may be assumed with confidence. We present here 230 Th- 234 U model-ages for several of these standards, determined by isotope dilution mass spectrometry using a multicollector ICP-MS, and compare these ages with their known production history

  3. 230Th-234U Model-Ages of Some Uranium Standard Reference Materials

    Energy Technology Data Exchange (ETDEWEB)

    Williams, R W; Gaffney, A M; Kristo, M J; Hutcheon, I D

    2009-05-28

    The 'age' of a sample of uranium is an important aspect of a nuclear forensic investigation and of the attribution of the material to its source. To the extent that the sample obeys the standard rules of radiochronometry, then the production ages of even very recent material can be determined using the {sup 230}Th-{sup 234}U chronometer. These standard rules may be summarized as (a) the daughter/parent ratio at time=zero must be known, and (b) there has been no daughter/parent fractionation since production. For most samples of uranium, the 'ages' determined using this chronometer are semantically 'model-ages' because (a) some assumption of the initial {sup 230}Th content in the sample is required and (b) closed-system behavior is assumed. The uranium standard reference materials originally prepared and distributed by the former US National Bureau of Standards and now distributed by New Brunswick Laboratory as certified reference materials (NBS SRM = NBL CRM) are good candidates for samples where both rules are met. The U isotopic standards have known purification and production dates, and closed-system behavior in the solid form (U{sub 3}O{sub 8}) may be assumed with confidence. We present here {sup 230}Th-{sup 234}U model-ages for several of these standards, determined by isotope dilution mass spectrometry using a multicollector ICP-MS, and compare these ages with their known production history.

  4. The Influence of Aging Period, Freezing Temperature and Packaging Material on Frozen Beef Chemical Quality

    Directory of Open Access Journals (Sweden)

    Aris Sri Widati

    2012-04-01

    Full Text Available The objective of the study was to evaluate the influences of aging period, freezing temperature and packaging material on the frozen beef chemical quality. The material of the study was 2-3 years old Ongole grade beef of the Longissimus dorsi part,  and was then classified into 3 treat­ments, namely A (aging periode; 0, 12 and 24 hours, B (freezing temperature; -10°C and -20°C and C (packaging material; aluminum foil (Al, polyprophylene (PP, poly­ethylene (PE and without packaging material. The ob­served variables were water content, crude protein, fat, ash content. The data were analyzed by the Completely Randomized Design (CRD in the Factorial (3x2x4 pattern. The results indicated that the aging periode de­creased the water content, and ash content significantly (P<0.05, and decreased the crude protein but increased the fat content insignificantly. The lower freezing temperature prevented the decreases of the water content, and ash content significantly (P<0.05, but prevented the decrease of crude protein, fat content insignificantly. The packaging material could prevent the decreases of water content, ash content sig­nificantly (P<0.05, but prevent the decreases of protein, and fat content insignificantly. A significant interaction (P<0.05 occured between the freezing temperature and packaging material factors on ash content of the frozen beef. The conclusion was the frozen beef without aging has a high of water content, protein, and ash, but has a low fat content.Temperature at -200C and using aluminium foil packaging can prevent decreasing quality of frozen beef. Keywords : Aging period, freezing temperature,  packaging material

  5. Knowledge of ageing phenomenons of materials used in the PWR power plants

    International Nuclear Information System (INIS)

    Vancon, D.; Meyzaud, Y.; Soulat, P.

    1996-01-01

    The nuclear power plants with PWR type reactors are planned to work during forty years and are the subject of studies aiming to check their integrity during all their life. The materials used to the fabrication of the components can be submitted different stress. The temperature, the mechanical constraints, the irradiation are examples of stress which can make the materials getting old. This text presents three themes: the ageing by irradiation, the thermal ageing and the corrosion, and their principle industrial consequences. (N.C.)

  6. [Problems associated with age estimation of underage persons who appear in child pornography materials].

    Science.gov (United States)

    Łabecka, Marzena; Lorkiewicz-Muszyńska, Dorota; Jarzabek-Bielecka, Grazyna

    2011-01-01

    Among opinions issued by the Forensic Medicine Department, Medical Science University in Poznan, in the last six years, there are opinions concerning age estimation in child pornography materials. The issue subject to research is indicating persons under the age of 15 years in pornographic materials, since possession of pornographic materials featuring underage persons is considered a crime and is subject to article 202 of the Penal Code. The estimation of the age of teenagers based on secondary and tertiary sexual characteristics is increasingly more difficult and the available data in professional literature regarding the standard time of development differ among various authors of such studies. In the report, an attempt has been made at determining the agreement regarding different characteristics in the data included in the Tanner's scale, which has been modified to accommodate the research done on persons registered by electronic means. The modified scale, which up to now has been used in research of registered subjects in classified public prosecutors' materials, has been employed in children seen in a pediatric outpatient department. The goal has been a comparison of the outcome of the research to prove its usefulness so that in the future, the modified scale could be used as a research tool in estimation of age of persons appearing in pornography materials. medical forms of 205 children seen in a pediatric outpatient department, based on the scale created by the present authors us and later processed using Excel.

  7. Aging linear viscoelasticity of matrix-inclusion composite materials featuring ellipsoidal inclusions

    OpenAIRE

    LAVERGNE, Francis; SAB, Karam; SANAHUJA, Julien; BORNERT, Michel; TOULEMONDE, Charles

    2016-01-01

    A multi-scale homogenization scheme is proposed to estimate the time-dependent strains of fiber-reinforced concrete. This material is modeled as an aging linear viscoelastic composite material featuring ellipsoidal inclusions embedded in a viscoelastic cementitious matrix characterized by a time-dependent Poisson's ratio. To this end, the homogenization scheme proposed in Lavergne et al. [1] is adapted to the case of a time-dependent Poisson's ratio and it is successfully validated on a non-a...

  8. Failure of structural elements made of polymer supported composite materials during the multiyear natural aging

    Science.gov (United States)

    Blinkov, Pavel; Ogorodov, Leonid; Grabovyy, Peter

    2018-03-01

    Modern high-rise construction introduces a number of limitations and tasks. In addition to durability, comfort and profitability, projects should take into account energy efficiency and environmental problems. Polymer building materials are used as substitutes for materials such as brick, concrete, metal, wood and glass, and in addition to traditional materials. Plastic materials are light, can be formed into complex shapes, durable and low, and also possess a wide range of properties. Plastic materials are available in various forms, colors and textures and require minimal or no color. They are resistant to heat transfer and diffusion of moisture and do not suffer from metal corrosion or microbial attack. Polymeric materials, including thermoplastics, thermoset materials and wood-polymer composites, have many structural and non-structural applications in the construction industry. They provide unique and innovative solutions at a low cost, and their use is likely to grow in the future. A number of polymer composite materials form complex material compositions, which are applied in the construction in order to analyze the processes of damage accumulation under the conditions of complex nonstationary loading modes, and to determine the life of structural elements considering the material aging. This paper present the results of tests on short-term compression loading with a deformation rate of v = 2 mm/min using composite samples of various shapes and sizes.

  9. Toxicity Determinations for Five Energetic Materials, Weathered and Aged in Soil, to the Collembolan Folsomia Candida

    Science.gov (United States)

    2015-03-01

    obtained from the Soil Fauna and Ecotoxicology Research Unit, Department of Terrestrial Ecology, National Environmental Research Institute (Silkeborg...AND AGED IN SOIL , TO THE COLLEMBOLAN FOLSOMIA CANDIDA ECBC-TR-1273 Carlton T. Phillips Ronald T. Checkai Roman G. Kuperman Michael Simini...for Five Energetic Materials, Weathered and Aged in Soil , to the Collembolan Folsomia candida 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  10. Crystal River 3 Cable Materials for Thermal and Gamma Radiation Aging

    Energy Technology Data Exchange (ETDEWEB)

    Fifield, Leonard S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Correa, Miguel [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zwoster, Andy [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-09-07

    The Expanded Materials Degradation Assessment Volume 5: Aging of Cables and Cable Systems (EMDA) summarizes the state of knowledge of materials, constructions, operating environments, and aging behavior of low voltage and medium cables in nuclear power plants (NPPs) and identifies potential knowledge gaps with regard to cable operation beyond 60 years. The greatest area of uncertainty relates to how well the accelerated aging used in the original equipment qualification (EQ) processes predicts the performance of cable materials in extended operation. General opinion and utility experience have indicated that actual operating environments of in-plant cables are not as severe, however, as the operating and design basis environments used in the qualification process. Better understanding of the long term aging behavior of cable insulation materials in service conditions and the analysis of actual cable operating environments are the objectives of ongoing research to support subsequent license renewal activities in particular and long term cable aging management in general. A key component of the effort to better understand cable material aging behavior is the availability of representative samples of cables that have been installed in operating light water reactors and have experienced long term service. Unique access to long term service cables, including relatively rich information on cable identity and history, occurred in 2016 through the assistance of the Electric Power Research Institute (EPRI). EPRI facilitated DOE receipt of harvested cables from the decommissioned Crystal River Unit 3 (CR3) pressurized water reactor representing six of the nine most common low voltage cable manufacturers (EPRI 103841R1): Rockbestos, Anaconda Wire and Cable Company (Anaconda), Boston Insulated Wire (BIW), Brand-Rex, Kerite and Okonite. Cable samples received had been installed in the operating plant for durations ranging from 10 years to 36 years. These cables provide the

  11. Effect of artificial aging on the surface roughness and microhardness of resin-based materials.

    Science.gov (United States)

    Santos, M Jacinta M C; Rêgo, Heleine Maria Chagas; Mukhopadhyay, Anuradha; El Najjar, Mai; Santos, Gildo C

    2016-01-01

    This study sought to verify the effects of aging on the surface roughness (Ra) and microhardness (Knoop hardness number [KHN]) of resin-based restorative materials protected with a surface sealer. Disc specimens of 2 resin-modified glass ionomers (RMGIs) and 1 composite resin (CR) were fabricated in a metal mold. Specimens of each material were divided into 1 group that was covered with surface sealer and 1 group that was not. Both groups of each material were then subdivided according to whether they were stored (aged) in cola or distilled water. Surface roughness and KHN values were obtained from each specimen before and after storage. After aging of the specimens, significantly higher Ra values were observed in the 2 RMGIs when they were not covered with a surface sealer, while the CR was not affected. The KHN values varied by materials and storage conditions (with and without a surface sealer). All the groups with a surface sealer exhibited increased Ra values after aging.

  12. How accelerated biological aging can affect solar reflective polymeric based building materials

    Science.gov (United States)

    Ferrari, C.; Santunione, G.; Libbra, A.; Muscio, A.; Sgarbi, E.

    2017-11-01

    Among the main issues concerning building materials, in particular outdoor ones, one can identify the colonization by microorganisms referred to as biological aggression. This can affect not only the aesthetical aspect but also the thermal performance of solar reflective materials. In order to improve the reliability of tests aimed to assess the resistance to biological aggression and contextually reduce the test duration, an accelerated test method has been developed. It is based on a lab reproducible setup where specific and controlled environmental and boundary conditions are imposed to accelerate as much as possible biological growth on building materials. Due to their widespread use, polymeric materials have been selected for the present analysis, in the aim of reaching an advanced bio-aged level in a relatively short time (8 weeks or less) and at the same time comparatively evaluate different materials under a given set of ageing conditions. Surface properties before, during and after ageing have been investigated by surface, microstructural and chemical analyses, as well as by examination of time progressive images to assess bacterial and algal growth rate.

  13. Dose rate effect on material aging due to radiation. [Gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, Shin-ichi (Radiation Center of Osaka Prefecture, Sakai (Japan)); Hayakawa, Chikara; Takeya, Chikashi

    1982-12-01

    Although many reports have been presented on the radiation aging of the organic materials for electric cables, those have been based on the experiments carried out at high dose rate near 1 x 10/sup 6/ rad/h, assuming that aging effect depends on only radiation dose. Therefore, to investigate the aging behaviour in low dose rate range is an important subject to predict their practical life time. In this report, the results of having investigated the aging behaviour of six types of materials are described, (polyethylene for general insulation purpose, chemically cross-linked polyethylene, fire-retardant chemically cross-linked polyethylene, fire-retardant ethylene-propylene rubber, fire-retardant chloro-sulfonated polyethylene for sheaths, and fire-retardant, low hydrochloric acid, special heat-resistant vinyl for insulation purpose or chloroclean). They were irradiated with /sup 60/Co ..gamma..-ray at the dose from 5 x 10/sup 3/ to 1 x 10/sup 6/ rad/h, and their deterioration was tested for the items of elongation, tensile strength, resistivity, dielectric tangent and gel fraction. The aging mechanism and dose rate effect were also considered. The dose rate effect appeared or did not appear depending on the types of materials and also their properties. The materials that showed the dose rate effect included the typical ones whose characteristics degraded with the decreasing dose rate, and the peculiar ones whose deterioration of characteristics did not appear constantly. Aging mechanism may vary in the case of high dose rate and low dose rate. Also, if the life time at respective dose rate in relatively higher dose rate region is clarified, the life time in low dose rate region may possibly be predicted.

  14. The difficult issue of age assessment on pedo-pornographic material.

    Science.gov (United States)

    Cattaneo, Cristina; Ritz-Timme, Stefanie; Gabriel, Peter; Gibelli, Daniele; Giudici, Elena; Poppa, Pasquale; Nohrden, Doerte; Assmann, Sabine; Schmitt, Roland; Grandi, Marco

    2009-01-10

    The issue of juvenile pornography has seen an increase in the past few years of the number of expert opinions requested to forensic pathologists, paediatricians and other various experts within the forensic and medical fields concerning the age of represented individuals. Regardless of the entity of the problem, no actual method exists which can allow us to give an objective and scientific answer, particularly in the postpubertal stage. Using parameters related to sexual maturation can be very dangerous. Nonetheless some experts still insist with similar types of "expertises". This study aims at verifying the ability of different experts in assessing age of postpubertal individuals represented in pornographic material. Results underline the difficulties and major uncertainties of age evaluation by visual observation of photographic material particularly when the subjects have reached the sexual maturation stage - and therefore in verifying whether the individual is above or below 18 years of age (an important age limit for most European countries as far as this type of crime is concerned). Furthermore the study stresses the need both to search for an alternate approach and to apply extreme caution in judicial evaluation.

  15. Does artificial aging affect mechanical properties of CAD/CAM composite materials.

    Science.gov (United States)

    Egilmez, Ferhan; Ergun, Gulfem; Cekic-Nagas, Isil; Vallittu, Pekka K; Lassila, Lippo V J

    2018-01-01

    The purpose of this study was to determine the flexural strength and Weibull characteristics of different CAD/CAM materials after different in vitro aging conditions. The specimens were randomly assigned to one of the six in vitro aging conditions: (1) water storage (37°C, 3 weeks), (2) boiling water (24h), (3) hydrochloric acid exposure (pH: 1.2, 24h), (4) autoclave treatment (134°C, 200kPa, 12h), (5) thermal cycling (5000 times, 5-55°C), (6) cyclic loading (100N, 50,000 cycles). No treatment was applied to the specimens in control group. Three-point bending test was used for the calculation of flexural strength. The reliability of the strength was assessed by Weibull distribution. Surface roughness and topography was examined by coherence scanning interferometry. Evaluated parameters were compared using the Kruskall-Wallis or Mann-Whitney U test. Water storage, autoclave treatment and thermal cycling significantly decreased the flexural strength of all materials (p0.05). Weibull moduli of Cerasmart™ and Lava™ Ultimate were similar with control. Vita Enamic ® exhibited similar Weibull moduli in all aging groups except the HCl treated group (p>0.05). R a values of Cerasmart™ and Lava™ Ultimate were in the range of 0.053-0.088μm in the aged groups. However R a results of Vita Enamic ® were larger than 0.2μm. Flexural strength of newly developed restorative CAD/CAM materials was significantly decreased by artificial aging. Cyclic loading or HCl exposure does not affect to the flexural strength and structural reliability of Cerasmart™ and Lava™ Ultimate. Copyright © 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  16. Accelerated Aging Effect on Epoxy-polysiloxane Polymeric Insulator Material with Rice Husk Ash Filler

    Directory of Open Access Journals (Sweden)

    Rochmadi .

    2012-12-01

    Full Text Available The performances of outdoor polymeric insulators are influenced by environmental conditions. This paper presents the effect of artificial tropical climate on the hydrophobicity, equivalent salt deposit density (ESDD, surface leakage current, flashover voltage, and surface degradation on epoxy-polysiloxane polymeric insulator materials with rice husk ash (RHA. Test samples are made at room temperature vulcanized (RTV of various composition of epoxy-polysiloxane with rice husk ash as filler. The aging was carried out in test chamber at temperature from 50oC to 62oC, relative humidity of 60% to 80%, and ultraviolet (UV  radiation 21.28 w/cm2 in daylight conditions for 96 hours. The experiment results showed that the flashover voltage fluctuates from 34.13 kV up to 40.92 kV and tends to decrease on each variation of material composition. The surface leakage current fluctuates and tends to increase. Test samples with higher filler content result greater hydrophobicity, smaller equivalent salt deposit density, and smaller critical leakage current, which caused the increase of the flashover voltage. Insulator material (RTVEP3 showed the best performance in tropical climate environment. Artificial tropical aging for short duration gives less effect to the surface degradation of epoxy-polysiloxane insulator material.

  17. A Study on Accelerated Thermal Aging of High Modulus Carbon/Epoxy Composite Material

    Directory of Open Access Journals (Sweden)

    Ju Min Kyung

    2015-01-01

    Full Text Available Composite materials have been used increasingly for various space applications due to the favorable characteristic of high modulus to density ratio and potential for near-zero coefficient of thermal expansion. In composite system, depending on the orientation of fibers, strength and stiffness can be changed so that the optimum structure can be accomplished. This is because the coefficient of thermal expansion (CTE of carbon fibers is negative. For spacecraft and orbiting space structure, which are thermally cycled by moving through the earth' shadow for at least 5 years, it is necessary to investigate the change of properties of the material over time. In this study, thermal aging of epoxy matrix/high modulus carbon fiber composite materials are accelerated to predict the long term creep property. Specimens are tested at various temperatures of 100~140°C with dynamic mechanical analysis to obtain creep compliances that are functions of time and temperature. Using Time Temperature Superposition method, creep compliance curves at each temperature are shifted to the reference temperature by shift factor and a master curve is generated at the reference temperature. This information is useful to predict the long term thermal aging of high modulus composite material for spacecraft application.

  18. Aging Mechanisms of Electrode Materials in Lithium-Ion Batteries for Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Cheng Lin

    2015-01-01

    Full Text Available Electrode material aging leads to a decrease in capacity and/or a rise in resistance of the whole cell and thus can dramatically affect the performance of lithium-ion batteries. Furthermore, the aging phenomena are extremely complicated to describe due to the coupling of various factors. In this review, we give an interpretation of capacity/power fading of electrode-oriented aging mechanisms under cycling and various storage conditions for metallic oxide-based cathodes and carbon-based anodes. For the cathode of lithium-ion batteries, the mechanical stress and strain resulting from the lithium ions insertion and extraction predominantly lead to structural disordering. Another important aging mechanism is the metal dissolution from the cathode and the subsequent deposition on the anode. For the anode, the main aging mechanisms are the loss of recyclable lithium ions caused by the formation and increasing growth of a solid electrolyte interphase (SEI and the mechanical fatigue caused by the diffusion-induced stress on the carbon anode particles. Additionally, electrode aging largely depends on the electrochemical behaviour under cycling and storage conditions and results from both structural/morphological changes and side reactions aggravated by decomposition products and protic impurities in the electrolyte.

  19. Sixth Status Report: Testing of Aged Softwood Fiberboard Material for the 9975 Shipping Package

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-03-31

    Samples have been prepared from several 9975 lower fiberboard subassemblies fabricated from softwood fiberboard. Physical, mechanical and thermal properties have been measured following varying periods of conditioning in each of several environments. These tests have been conducted in the same manner as previous testing on cane fiberboard samples. Overall, similar aging trends are observed for softwood and cane fiberboard samples, with a few differences. Some softwood fiberboard properties tend to degrade faster in some environments, while some cane fiberboard properties degrade faster in the two most aggressive environments. As a result, it is premature to assume both materials will age at the same rates, and the preliminary aging models developed for cane fiberboard might not apply to softwood fiberboard. However, it is expected that both cane and softwood fiberboard assemblies will perform satisfactorily in conforming packages stored in a typical KAC storage environment for up to 15 years. Samples from an additional 3 softwood fiberboard assemblies have begun aging during the past year to provide information on the variability of softwood fiberboard behavior. Aging and testing of softwood fiberboard will continue and additional data will be collected to support development of an aging model specific to softwood fiberboard.

  20. Ageing studies on materials, components and process instruments used in nuclear power plants

    International Nuclear Information System (INIS)

    Bora, J.S.

    1997-04-01

    This report is a compilation of test results of thermal and radiation ageing tests carried out in the laboratory over a period of 25 years on diverse engineering materials, components and instruments used in nuclear power plants. Test items covered are different types of electrical cables, elastomers, surface coatings, electrical and electronics components and process instruments. Effects of thermal and radiation ageing on performance parameters are shown in tabular forms. Apart from finding the characteristics, capabilities and limitations of test items, ageing research has helped in pin-pointing sub-standard and critical parts and necessary corrective action has been taken. This report is expected to be quite useful to the manufacturers users and researchers for reference and guidance. (author)

  1. LEVERAGING AGING MATERIALS DATA TO SUPPORT EXTENSION OF TRANSPORTATION SHIPPING PACKAGES SERVICE LIFE

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, K. [Savannah River National Laboratory; Bellamy, S. [Savannah River National Laboratory; Daugherty, W. [Savannah River National Laboratory; Sindelar, R. [Savannah River National Laboratory; Skidmore, E. [Savannah River National Laboratory

    2013-08-18

    Nuclear material inventories are increasingly being transferred to interim storage locations where they may reside for extended periods of time. Use of a shipping package to store nuclear materials after the transfer has become more common for a variety of reasons. Shipping packages are robust and have a qualified pedigree for performance in normal operation and accident conditions but are only certified over an approved transportation window. The continued use of shipping packages to contain nuclear material during interim storage will result in reduced overall costs and reduced exposure to workers. However, the shipping package materials of construction must maintain integrity as specified by the safety basis of the storage facility throughout the storage period, which is typically well beyond the certified transportation window. In many ways, the certification processes required for interim storage of nuclear materials in shipping packages is similar to life extension programs required for dry cask storage systems for commercial nuclear fuels. The storage of spent nuclear fuel in dry cask storage systems is federally-regulated, and over 1500 individual dry casks have been in successful service up to 20 years in the US. The uncertainty in final disposition will likely require extended storage of this fuel well beyond initial license periods and perhaps multiple re-licenses may be needed. Thus, both the shipping packages and the dry cask storage systems require materials integrity assessments and assurance of continued satisfactory materials performance over times not considered in the original evaluation processes. Test programs for the shipping packages have been established to obtain aging data on materials of construction to demonstrate continued system integrity. The collective data may be coupled with similar data for the dry cask storage systems and used to support extending the service life of shipping packages in both transportation and storage.

  2. The effect of extended aging on the optical properties of different zirconia materials.

    Science.gov (United States)

    Alghazzawi, Tariq F

    2017-07-01

    The purpose of this study was to determine if the optical properties of zirconia and glass-ceramic (e.max) were affected by low-temperature degradation (aging). Experiment samples were fabricated with seven zirconia brands (n=10): Zenostar, Zirlux, Katana, Bruxzir, DD-BioZX 2 , DD-cubeX 2 , NexxZr; and e.max were used as a control. This resulted in a total of 80 samples in the experiment. The L*, a* and b* were measured for each sample, and then the optical properties including translucency parameter (TP), contrast ratio (CR), and opalescence parameter (OP) were calculated. The samples were aged (20, 40, 60, 80, 100h), and the optical properties were calculated after each interval. Most zirconia brands had lower L*, higher a*, higher b* with increased aging, which visually corresponds to darker, redder, and more yellow. Aging also increased CR, lowered TP, and lowered OP. e.max was also affected by aging but still had the highest TP (23.9±2.8), L* (81.7±3.4), and lowest CR (0.41±0.05) compared to any zirconia. The Zenostar had the closest TP (24.1±0.4), and L* (90.2±0.5) values to e.max before aging. However, after 100h of aging, the DD-cubeX 2 was least effected and had the highest TP (22.2±0.6) and lowest CR (0.43±0.01) compared with other zirconia samples and highest OP (11.3±0.2) of all ceramic samples. The optical properties of zirconia and e.max materials were affected by aging with the effects increasing with time. The magnitude of change was affected by seven brands of dental zirconia. Copyright © 2016 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  3. All the things I have - handling one's material room in old age.

    Science.gov (United States)

    Larsson Ranada, Asa; Hagberg, Jan-Erik

    2014-12-01

    The article explores how old people who live in their ordinary home, reason and act regarding their 'material room' (technical objects, such as household appliances, communication tools and things, such as furniture, personal belongings, gadgets, books, paintings, and memorabilia). The interest is in how they, as a consequence of their aging, look at acquiring new objects and phasing out older objects from the home. This is a broader approach than in most other studies of how old people relate to materiality in which attention is mostly paid either to adjustments to the physical environment or to the importance of personal possessions. In the latter cases, the focus is on downsizing processes (e.g. household disbandment or casser maison) in connection with a move to smaller accommodation or to a nursing home. The article is based on a study in which thirteen older people (median age 87), living in a Swedish town of medium size were interviewed (2012) for a third time. The questions concerned the need and desire for new objects, replacement of broken objects, sorting out the home or elsewhere, most cherished possessions, and the role of family members such as children and grandchildren. The results reveal the complexity of how one handles the material room. Most evident is the participants' reluctance to acquire new objects or even to replace broken things. Nearly all of them had considered, but few had started, a process of sorting out objects. These standpoints in combination resulted in a relatively intact material room, which was motivated by an ambition to simplify daily life or to facilitate the approaching dissolution of the home. Some objects of special value and other cherished objects materialized the connections between generations within a family. Some participants wanted to spare their children the burden of having to decide on what to do with their possessions. Others (mostly men), on the contrary, relied on their children to do the sorting out after

  4. Measurement of volume change in cementitious materials at early ages - Review of testing protocols and interpretation of results

    DEFF Research Database (Denmark)

    Sant, Gaurav; Lura, Pietro; Weiss, Jason

    2006-01-01

    Early-age cracking in concrete bridge decks, pavements, and superstructure elements has served as the impetus for substantial research on early-age shrinkage in cementitious materials. Much of this research has indicated how mixture proportions, constituent materials, and construction operations...

  5. Material property evaluations of bimetallic welds, stainless steel saw fusion lines, and materials affected by dynamic strain aging

    Energy Technology Data Exchange (ETDEWEB)

    Rudland, D.; Scott, P.; Marschall, C.; Wilkowski, G. [Battelle Memorial Institute, Columbus, OH (United States)

    1997-04-01

    Pipe fracture analyses can often reasonably predict the behavior of flawed piping. However, there are material applications with uncertainties in fracture behavior. This paper summarizes work on three such cases. First, the fracture behavior of bimetallic welds are discussed. The purpose of the study was to determine if current fracture analyses can predict the response of pipe with flaws in bimetallic welds. The weld joined sections of A516 Grade 70 carbon steel to F316 stainless steel. The crack was along the carbon steel base metal to Inconel 182 weld metal fusion line. Material properties from tensile and C(T) specimens were used to predict large pipe response. The major conclusion from the work is that fracture behavior of the weld could be evaluated with reasonable accuracy using properties of the carbon steel pipe and conventional J-estimation analyses. However, results may not be generally true for all bimetallic welds. Second, the toughness of austenitic steel submerged-arc weld (SAW) fusion lines is discussed. During large-scale pipe tests with flaws in the center of the SAW, the crack tended to grow into the fusion line. The fracture toughness of the base metal, the SAW, and the fusion line were determined and compared. The major conclusion reached is that although the fusion line had a higher initiation toughness than the weld metal, the fusion-line J-R curve reached a steady-state value while the SAW J-R curve increased. Last, carbon steel fracture experiments containing circumferential flaws with periods of unstable crack jumps during steady ductile tearing are discussed. These instabilities are believed to be due to dynamic strain aging (DSA). The paper discusses DSA, a screening criteria developed to predict DSA, and the ability of the current J-based methodologies to assess the effect of these crack instabilities. The effect of loading rate on the strength and toughness of several different carbon steel pipes at LWR temperatures is also discussed.

  6. Las Lunas (Yuncler, Toledo. A Bronze Age hoard with metallic materials from the southern Iberian Meseta

    Directory of Open Access Journals (Sweden)

    Urbina Martínez, Dionisio

    2010-06-01

    Full Text Available Here we present the results of the preliminary study carried out on a new group of metallic materials of the Final Bronze Age, recovered at the end of 2008 in the archaeological excavations at the settlement of Las Lunas (Yuncler, Toledo, Spain. Its geographical situation far away from the main zones of distribution of this type of finds, the singularity of the materials, and the evidence of Atlantic and Mediterranean relations make these materials a remarkable sample for the study of the Final Bronze Age in the centre of the Iberian Peninsula.

    Se exponen los resultados del primer estudio realizado sobre un nuevo conjunto de materiales metálicos del Bronce Final recuperado a finales de 2008 en las excavaciones arqueológicas del yacimiento de Las Lunas (Yuncler, Toledo, España. La localización geográfica del hallazgo, lejos de las principales zonas de dispersión conocidas para este tipo de conjuntos, la singularidad de los objetos que integra, y las relaciones atlánticas y mediterráneas que evidencian sus materiales, lo convierten en un ejemplo destacado para el estudio de este período en el centro de la Península Ibérica.

  7. Application of positron age-momentum correlation measurements to the study of defects in inorganic materials

    International Nuclear Information System (INIS)

    Tanigawa, S.; Kishimoto, Y.; Tsuda, N.

    1982-01-01

    The two parameter correlation measurements between the positron age and the momentum of annihilating pairs were applied to the study of defects in plastically deformed MgO and Al 2 O 3 single crystals, nonstoichiometric sintered BaTiO 3 samples and irradiated NaCl single crystals. The results in MgO, Al 2 O 3 and BaTiO 3 showed the bell shape dependence of lifetimes on momentum indicating that the behavior of positrons in these materials can be well described by the simple trapping model with the condition that all positrons are initially in a free Bloch state. On the other hand, the X-ray irradiation of NaCl crystals produced a complicated dependence of lifetime momentum indicating the presence of positronium in this material. (Auth.)

  8. A novel facility for ageing materials with narrow-band ultraviolet radiation exposure

    International Nuclear Information System (INIS)

    Kaerhae, Petri; Ruokolainen, Kimmo; Heikkilae, Anu; Kaunismaa, Merja

    2011-01-01

    A facility for exploring wavelength dependencies in ultraviolet (UV) radiation induced degradation in materials has been designed and constructed. The device is essentially a spectrograph separating light from a lamp to spectrally resolved UV radiation. It is based on a 1 kW xenon lamp and a flat-field concave holographic grating 10 cm in diameter. Radiation at the wavelength range 250-500 nm is dispersed onto the sample plane of 1.5 cm in height and 21 cm in width. The optical performance of the device has been characterized by radiometric measurements. Using the facility, test samples prepared of regular newspaper have been irradiated from 1 to 8 h. Color changes on the different locations of the aged samples have been quantified by color measurements. Yellowness indices computed from the color measurements demonstrate the capability of the facility in revealing wavelength dependencies of the material property changes in reasonable time frames.

  9. Isotopic fractionation of NBS oxalic acid and its influence in the calculated age of materials

    International Nuclear Information System (INIS)

    Nehmi, V.A.

    1979-10-01

    The intensity of the isotopic fractionation during the oxidation of NBS oxalic acid to carbon dioxide was checked. 30 reactions of oxidation of NBS oxalic acid with potassium permanganate were made. The resultant isotopic composition of CO 2 has been determined with a mass-spectrometer. A conclusion has been reached that the average of Δ 13 C is - 18.9% o with variation between - 17.7 and - 21.2%o. For values of Δ 13 C equal to - 22.0%o, the calculated age with isotopic correction shows the following deviations in relation to non-corrected age: 4% for materials of 1,000 years and 0.3% for 20,000 years.(Author) [pt

  10. Episodic encoding in normal aging: attentional resources hypothesis extended to musical material.

    Science.gov (United States)

    Blanchet, Sophie; Belleville, Sylvie; Peretz, Isabelle

    2006-01-01

    The goal of the present study was to examine age-related changes in musical episodic memory for novel tunes. This was conducted by manipulating the encoding condition in a recognition paradigm. After receiving memory instructions (intentional condition), older and younger participants obtained equivalent hits. In contrast, when intentional encoding was accompanied by a dancing judgment (dancing + intentional condition), the recognition performance of the older persons was severely impaired. Impaired recognition was also found when participants only judged the excerpts without being instructed to memorize them (dancing judgment condition). Although older participants demonstrated a preserved ability to perform the dancing judgment on its own, this ability was not optimal and likely precluded the initiation of more elaborate encoding strategies. These results suggest that asking older persons to divide their attention in the study phase reduces the quality of their musical encoding. Given this extension to musical material, we discuss the notion that the age-related attentional resource decline appears to be domain-general rather than specific to verbal material.

  11. Proceedings of the international workshop on aged and decommissioned material collection and testing for structural integrity purposes

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-07-01

    This workshop was sponsored by the CEC DG XI and XII/JRC Petten/AMES and by the Principal Working Group 3 (PWG-3) on reactor component integrity of the NEA CSNI, and it was hosted by the CEN Mol, Belgium. The activities of PWG-3 fall into three main areas: non-destructive examination (NDE), fracture analysis, and ageing/materials degradation. The topic of the workshop falls into the third area of ageing and materials degradation. The titles of the papers are: AMES and other European networks in Integrity of Ageing Structures; Over View of Proving Test on the Reliability of Material of Nuclear Power Plant Components; Activities on Ageing Degradation Phenomena of NPP in Korea; Capability of Investigation on Decommissioned Parts from NPPs at the MPA Stuttgart; How Accurately can Surveillance Specimens Reflect the True State of RPV Materials?; Applicability of Design Codes to Aged Materials; Microstructural Investigations of as-Fabricated, Long-Term Thermally Aged and Neutron Irradiated RPV Materials: An Atom Probe Study; Proposed Post-Service Investigations on Decommissioned Greifswald Units; Tools and Experience in Post Irradiation Examination of Structural Core Components at PSI Hot laboratory; Testing of Beznau NPP Unit 1 Steam Generator Cast Stainless Steel Elbows; Mechanical Properties Characterisation of Irradiated Materials From Operating or Decommissioned Nuclear Power Plants; Long Term Ageing of Cast Ti-Stabilised Stainless Steel; Enhanced Surveillance of Nuclear Reactor Pressure Vessels. Discussions and conclusions are also presented

  12. Evaluation of thermal aging effect on primary pipe material in nuclear power plant by micro hardness test method

    International Nuclear Information System (INIS)

    Xue Fei; Yu Weiwei; Wang Zhaoxi; Ma Qinzheng; Liu Wei

    2012-01-01

    The investigation was carried out on the changes in mechanical properties of the primary pipe material Z3CN20.09M after 10000 h aging at 400℃ by using micro- Vickers and impact testing machine. The results show that the impact energy of testing material decreases. However, the micro-Vickers hardness of ferrite phase and austenite phase which constitute the testing material increase and keep constant, respectively. The intrinsic relations were analyzed between the micro-Vickers hardness and the impact energy to make an attempt to present the micro-Vickers hardness measurement as a method applicable to evaluating the thermal aging of the primary pipe material. (authors)

  13. Regulatory challenges in the management of aging of structural materials in nuclear power plants

    International Nuclear Information System (INIS)

    Castelo, C.; Mendoza, C.; Mas, E.; Conde, J. M.

    2013-01-01

    The article discusses two major pathways by which a regulatory body, and in particular the CSN, may participate in the acquisition of the necessary knowledge on mechanisms of aging of nuclear structural materials: to participate in forums to share operational experience and R and R project, both nationally and internationally. It notes the importance of this participation to carry out its regulatory function based on the knowledge acquired and the unique challenge of transferring that knowledge to rules and guidelines for their application. The article discusses various R and D projects in which the CSN participates directly. It calls for the presence of regulatory bodies in R and D project funded by the EU and the transfer of the results of such projects to codes, standards or guidelines for feasible implementation. (Author)

  14. PWSCC issues and material aging management for nuclear power plants in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Seong Sik; Lim, Yun Soo; Kim, Dong Jin; Kim, Sung Woo; Kim, Hong Pyo [Nuclear Materials Research Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-10-15

    The primary water stress corrosion cracking (PWSCC) of alloy 600 in a PWR has been reported in the control rod drive mechanism (CRDM). Beginning in the mid-seventies, the pressurized water reactor (PWR) plants suffered from a sequence of SCC events mostly confined to S/G tubes, initially ODSCC, and then PWSCC. PWSCC was first reported in Bugey 3 vessel head penetration made of forged alloy 600 materials in September 1991. Other PWRs experienced cracking attributed to the PWSCC of the major primary side weld area made from alloy 182 at the end of the year 2000. Examples of dissimilar metal butt welds between the main austenitic stainless steel primary circuit piping and the outlet pressure vessel nozzles are the cracking of Ringhals 4, V. C. Summer and some J-groove welds of the CRDM of the RVH at Oconee 1. In addition to the Reactor Vessel Head (RVH), the PWSCC of alloy 182/82 has been reported at bottom mounted instrumentation (BMI) nozzle J-welds, steam generator(SG) J-weld drain nozzle, and SG tube sheet cladding. Two cases of boric acid precipitation were reported at the bottom head surface of a SG in Korea. Cracking was found in the cold leg drain nozzles made of alloy 600 in two units, hot side nozzles were fabricated with alloy 690 from the beginning. The cracking of steam generator tubings made of alloy 600 is another concern in Korea, because some plants still have alloy 600 HTMA tubings. The flow accelerated corrosion of secondary pipings is another type of corrosion problems, though it has not been treated as a severe problem in Korea. To properly manage the corrosion issues and seek out research items for maintaining the integrity of nuclear plants, the PRIMA-Net (Proactive Research and Innovative Material Aging Network) was organized in 2007. The research and development expert group consists of a National research laboratory (KAERI), regulatory body (KINS), utility (KHNP), engineering and design company (KEPCO EC), manufacturer (Doosan Heavy

  15. Nb-base FS-85 Alloy as a Candidate Structural Material for Space Reactor Applications: Effects of Thermal Aging

    International Nuclear Information System (INIS)

    Leonard, Keith J.; Busby, Jeremy T.; Hoelzer, David T.; Zinkle, Steven J.

    2009-01-01

    The proposed use of fission reactors for manned or deep space missions have typically relied on the potential use of refractory metal alloys as structural materials. Throughout the history of these programs, the lead candidate has been Nb-1Zr due to its good fabrication and welding characteristics. However, the less than optimal creep resistance of this alloy has encouraged interest in the more complex FS-85 (Nb-28Ta-10W-1Zr) alloy. Despite this interest, a relatively small database exists for the properties of FS-85. These gaps include potential microstructural instabilities that can lead to mechanical property degradation. In this work, changes in microstructure and mechanical properties of FS-85 were investigated following 1100 h of thermal aging at 1098, 1248 and 1398 K. The changes in electrical resistivity, hardness and tensile properties between the as-annealed and aged materials are compared. Evaluation of the microstructural changes was performed through optical, scanning and transmission electron microscopy. The development of intragranular and grain boundary precipitation of Zr-rich compounds as a function of aging temperature was followed. Brittle tensile behavior was measured in the 1248 K aged material, while ductile behavior occurred in material aged above and below this temperature. The effect of temperature on the under and overaging of the grain boundary particles are believed to have contributed to the mechanical property behavior of the aged material

  16. Difference in radiocarbon ages of carbonized material from the inner and outer surfaces of pottery from a wetland archaeological site.

    Science.gov (United States)

    Miyata, Yoshiki; Minami, Masayo; Onbe, Shin; Sakamoto, Minoru; Matsuzaki, Hiroyuki; Nakamura, Toshio; Imamura, Mineo

    2011-01-01

    AMS (Accelerator Mass Spectrometry) radiocarbon dates for eight potsherds from a single piece of pottery from a wetland archaeological site indicated that charred material from the inner pottery surfaces (5052 ± 12 BP; N = 5) is about 90 (14)C years older than that from the outer surfaces (4961 ± 22 BP; N = 7). We considered three possible causes of this difference: the old wood effect, reservoir effects, and diagenesis. We concluded that differences in the radiocarbon ages between materials from the inner and outer surfaces of the same pot were caused either by the freshwater reservoir effect or by diagenesis. Moreover, we found that the radiocarbon ages of carbonized material on outer surfaces (soot) of pottery from other wetland archaeological sites were the same as the ages of material on inner surfaces (charred food) of the same pot within error, suggesting absence of freshwater reservoir effect or diagenesis.

  17. Temperature and humidity effect on aging of silicone rubbers as sealing materials for proton exchange membrane fuel cell applications

    International Nuclear Information System (INIS)

    Chang, Huawei; Wan, Zhongmin; Chen, Xi; Wan, Junhua; Luo, Liang; Zhang, Haining; Shu, Shuiming; Tu, Zhengkai

    2016-01-01

    Highlights: • Aging of silicone rubbers with different hardness was investigated. • Existed water molecules from humidified gases can accelerate the aging process. • Silicone rubber with hardness of 40 is more suitable as sealing materials. • Silicone rubbers can be used as sealing materials below 80 °C but not above 100 °C. - Abstract: Durability and reliability of seals around perimeter of each unit are critical to the lifetime of proton exchange membrane fuel cells. In this study, we investigate the aging of silicone rubbers with different hardness, often used as sealing materials for fuel cells, subjected to dry and humidified air at different temperatures. The aging properties are characterized by variation of permanent compression set value under compression, mechanical properties, and surface morphology as well. The results show that aging of silicone rubbers becomes more severe with the increase in subjected temperature. At temperature above 100 °C, silicone rubbers are not suitable for fuel cell applications. The existed water molecules from humidified gases can accelerate the aging of silicone rubbers. Among the tested samples, silicone rubber with hardness of 40 is more durable than that with hardness of 30 and 50 for fuel cells. The change of chemical structure after aging suggests that the aging of silicone rubbers mainly results from the chemical decomposition of cross-linker units for connection of polysiloxane backbones and of methyl groups attached to silicon atoms.

  18. Experimental characterization of thermal and hygric properties of hemp concrete with consideration of the material age evolution

    Science.gov (United States)

    Bennai, F.; Issaadi, N.; Abahri, K.; Belarbi, R.; Tahakourt, A.

    2018-04-01

    The incorporation of plant crops in construction materials offers very good hygrothermal performance to the building, ensuring substantial environmental and ecological benefits. This paper focuses on studying the evolution of hygrothermal properties of hemp concrete over age (7, 30 and 60 days). The analysis is done with respect to two main hygric and thermal properties, respectively: sorption isotherms, water vapor permeability, thermal conductivity and heat capacity. In fact, most of these parameters are very susceptible to change function of the age of the material. This influence of the aging is mainly due to the evolution of the microstructure with the binder hydration over time and the creation of new hydrates which can reduces the porosity of the material and consequently modify its properties. All the tested hemp concrete samples presented high moisture storage capacity and high-water vapor permeability whatever the age of such hygroscopic material. These hygric parameters increase significantly for high relative humidity requiring more consideration of such variability during the modeling of coupled heat and mass transfer within the material. By the same, the thermal conductivity and heat capacity tests highlighted the impact of the temperature and hygric state of the studied material.

  19. Nb-Base FS-85 Alloy as a Candidate Structural Material for Space Reactor Applications: Effects of Thermal Aging

    Science.gov (United States)

    Leonard, Keith J.; Busby, Jeremy T.; Hoelzer, David T.; Zinkle, Steven J.

    2009-04-01

    The proposed uses of fission reactors for manned or deep space missions have typically relied on the potential use of refractory metal alloys as structural materials. Throughout the history of these programs, a leading candidate has been Nb-1Zr, due to its good fabrication and welding characteristics. However, the less-than-optimal creep resistance of this alloy has encouraged interest in the more complex FS-85 (Nb-28Ta-10W-1Zr) alloy. Despite this interest, only a relatively small database exists for the properties of FS-85. Database gaps include the potential microstructural instabilities that can lead to mechanical property degradation. In this work, changes in the microstructure and mechanical properties of FS-85 were investigated following 1100 hours of thermal aging at 1098, 1248, and 1398 K. The changes in electrical resistivity, hardness, and tensile properties between the as-annealed and aged materials are compared. Evaluation of the microstructural changes was performed through optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The development of intragranular and grain-boundary precipitation of Zr-rich compounds as a function of aging temperature was followed. Brittle tensile behavior was measured in the material aged at 1248 K, while ductile behavior occurred in samples aged above and below this temperature. The effect of temperature on the under- and overaging of the grain-boundary particles is believed to have contributed to the mechanical property behavior of the aged materials.

  20. Color stability of sealed composite resin restorative materials after ultraviolet artificial aging and immersion in staining solutions.

    Science.gov (United States)

    Catelan, Anderson; Briso, André Luiz Fraga; Sundfeld, Renato Hermann; Goiato, Marcelo Coelho; dos Santos, Paulo Henrique

    2011-04-01

    The color alteration of resin-based materials is one of the most common reasons to replace esthetic dental restorations. This study assessed the influence of surface sealant (Biscover) on the color stability of nanofilled (Supreme XT) and microhybrid (Vit-l-escence and Opallis) composite resins after artificial aging. One hundred disc-shaped (6 × 1.5 mm) specimens were made for each composite resin. After 24 hours, all specimens were polished and sealant was applied to 50 specimens of each material. Baseline color was measured according to the CIE L*a*b* system using a reflection spectrophotometer. Ten specimens of each group were aged for 252 h in an ultraviolet (UV)-accelerated aging chamber or immersed for 4 weeks in cola soft drink, orange juice, red wine staining solutions or distilled water as control. Color difference (ΔE) after aging was calculated based on the color coordinates before (baseline) and after aging/staining treatment. Data were analyzed with 2-way ANOVA and Fisher's test (α=.05). The results showed significant changes in color after artificial aging in all the groups (Paging, and the cola soft drink. The lowest values of ΔE were found for specimens stored in distilled water. All composite resins showed some color alteration after the aging methods. The surface sealant did not alter the color stability of the tested materials. Copyright © 2011 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

  1. Age

    Science.gov (United States)

    ... adults? How can you reduce anesthesia risks in older patients? Age Age may bring wisdom but it also brings ... Ask your physician to conduct a pre-surgery cognitive test — an assessment of your mental function. The physician can use the results as a ...

  2. Study of Polymer Material Aging by Laser Mass Spectrometry, UV-Visible Spectroscopy, and Environmental Scanning Electron Microscopy

    OpenAIRE

    Junien Exposito; Claude Becker; David Ruch; Frédéric Aubriet

    2007-01-01

    Dyed natural rubber (NR) and styrene butadiene rubber (SBR), designed for outdoor applications, were exposed to an accelerated artificial aging in xenon light. The aging results in the deterioration of the exposed surface material properties. The ability of dyed polymers to withstand prolonged sunlight exposure without fading or undergoing any physical deterioration is largely determined not only by the photochemical characteristics of the absorbing dyestuff itself but also by the polymer str...

  3. Aging

    International Nuclear Information System (INIS)

    Sasaki, Hideo; Kodama, Kazunori; Yamada, Michiko

    1991-01-01

    The hypothesis that exposure to ionizing radiation accelerates the aging process has been actively investigated at ABCC-RERF since 1958, when longitudinal cohort studies of the Adult Health Study (AHS) and the Life Span Study (LSS) were initiated. In their 1975 overall review of aging studies related to the atomic bomb (A-bomb) survivors, Finch and Beebe concluded that while most studies had shown no correlation between aging and radiation exposure, they had not involved the large numbers of subjects required to provide strong evidence for or against the hypothesis. Extending LSS mortality data up to 1978 did not alter the earlier conclusion that any observed life-shortening was associated primarily with cancer induction rather than with any nonspecific cause. The results of aging studies conducted during the intervening 15 years using data from the same populations are reviewed in the present paper. Using clinical, epidemiological, and laboratory techniques, a broad spectrum of aging parameters have been studied, such as postmortem morphological changes, tests of functional capacity, physical tests and measurements, laboratory tests, tissue changes, and morbidity. With respect to the aging process, the overall results have not been consistent and are generally thought to show no relation to radiation exposure. Although some preliminary results suggest a possible radiation-induced increase in atherosclerotic diseases and acceleration of aging in the T-cell-related immune system, further study is necessary to confirm these findings. In the future, applying the latest gerontological study techniques to data collected from subjects exposed 45 years ago to A-bomb radiation at relatively young ages will present a new body of data relevant to the study of late radiation effects. (author) 103 refs

  4. Assessment of Cable Aging Equipment, Status of Acquired Materials, and Experimental Matrix at the Pacific Northwest National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Fifield, Leonard S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Westman, Matthew P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zwoster, Andy [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Schwenzer, Birgit [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-03-30

    The need for increased understanding of the aging and degradation behavior for polymer components of nuclear power plant electrical cables is described in this report. The highest priority materials for study and the resources available at PNNL for these studies are also described. The anticipated outcomes of the PNNL work described are : improved understanding of appropriate accelerated aging conditions, improved knowledge of correlation between observable aging indicators and cable condition in support of advanced non-destructive evaluation methods, and practical knowledge of condition-based cable lifetime prediction.

  5. Aging

    International Nuclear Information System (INIS)

    Finch, S.C.; Beebe, G.W.

    1975-01-01

    The hypothesis that ionizing radiation accelerates natural aging has been under investigation at the Atomic Bomb Casualty Commission since 1959. Postmortem observations of morphologic and chemical changes, tests of functional capacity, physical tests and measurements, clinical laboratory tests, tissue changes, morbidity, and mortality have all been examined by ABCC investigators interested in this hypothesis. These studies have been beset with conceptual difficulties centered on the definition and measurement of aging. An empirical approach early led to the calculation of an index of physiologic age as a linear combination of age-related tests of various organ systems. Most studies have been negative but have not involved the large numbers that might be required to provide strong evidence for or against the hypothesis. Mortality, however, has been examined on the basis of a large sample and over the period 1950-1972 had provided no support for the hypothesis of radiation-accelerated aging. Ionizing radiation dose, of course shorten human life, but its life-shortening effect appears to be the result of specific radiation-induced disease, especially neoplasms. The hypothesis is now much less attractive than it was 10-20 years ago but still has some value in stimulating research on aging. The experience of the A-bomb survivors provides an unusual opportunity for a definitive test of the hypothesis. (auth.)

  6. Material aging and degradation detection and remaining life assessment for plant life management

    International Nuclear Information System (INIS)

    Ramuhalli, P.; Henager, C.H. Jr.; Griffin, J.W.; Meyer, R.M.; Coble, J.B.; Pitman, S.G.; Bond, L.J.

    2012-01-01

    One of the major factors that may impact long-term operations is structural material degradation. Detecting materials degradation, estimating the remaining useful life (RUL) of the component, and determining approaches to mitigating the degradation are important from the perspective of long-term operations. In this study, multiple nondestructive measurement and monitoring methods were evaluated for their ability to assess the material degradation state. Metrics quantifying the level of damage from these measurements were defined and evaluated for their ability to provide estimates of remaining life of the component. An example of estimating the RUL from nondestructive measurements of material degradation condition is provided. (author)

  7. Metallic materials for the hydrogen energy industry and main gas pipelines: complex physical problems of aging, embrittlement, and failure

    International Nuclear Information System (INIS)

    Nechaev, Yu S

    2008-01-01

    The possibilities of effective solutions of relevant technological problems are considered based on the analysis of fundamental physical aspects, elucidation of the micromechanisms and interrelations of aging and hydrogen embrittlement of materials in the hydrogen industry and gas-main industries. The adverse effects these mechanisms and processes have on the service properties and technological lifetime of materials are analyzed. The concomitant fundamental process of formation of carbohydride-like and other nanosegregation structures at dislocations (with the segregation capacity 1 to 1.5 orders of magnitude greater than in the widely used Cottrell 'atmosphere' model) and grain boundaries is discussed, as is the way in which these structures affect technological processes (aging, hydrogen embrittlement, stress corrosion damage, and failure) and the physicomechanical properties of the metallic materials (including the technological lifetimes of pipeline steels). (reviews of topical problems)

  8. Grinding With Diamond Burs and Hydrothermal Aging of a Y-TZP Material: Effect on the Material Surface Characteristics and Bacterial Adhesion.

    Science.gov (United States)

    Dutra, Dam; Pereira, Gkr; Kantorski, K Z; Exterkate, Ram; Kleverlaan, C J; Valandro, L F; Zanatta, F B

    The aim of this study was to evaluate the effect of grinding with diamond burs and low-temperature aging on the material surface characteristics and bacteria adhesion on a yttrium-stabilized tetragonal zirconia polycrystalline (Y-TZP) surface. Y-TZP specimens were made from presintered blocks, sintered as recommended by the manufacturer, and assigned into six groups according to two factors-grinding (three levels: as sintered, grinding with extra-fine diamond bur [25-μm grit], and grinding with coarse diamond bur [181-μm grit]) and hydrothermal aging-to promote low-temperature degradation (two levels: presence/absence). Phase transformation (X-ray diffractometer), surface roughness, micromorphological patterns (atomic force microscopy), and contact angle (goniometer) were analyzed. Bacterial adhesion (colony-forming units [CFU]/biofilm) was quantified using an in vitro polymicrobial biofilm model. Both the surface treatment and hydrothermal aging promoted an increase in m-phase content. Roughness values increased as a function of increasing bur grit sizes. Grinding with a coarse diamond bur resulted in significantly lower values of contact angle (p0.05). Grinding with diamond burs and hydrothermal aging modified the Y-TZP surface properties; however, these properties had no effect on the amount of bacteria adhesion on the material surface.

  9. A test of the 40Ar/39Ar age spectrum technique on some terrestrial materials

    Science.gov (United States)

    Lanphere, M.A.; Brent, Dalrymple G.

    1971-01-01

    40Ar/39Ar age spectra were determined for 10 terrestrial rock and mineral samples whose geologic history is known from independent evidence. The spectra for six mineral and whole rock samples, including biotite, feldspar, hornblende, muscovite, and granodiorite, that have experienced post-crystallization heating did not reveal the age of crystallization in any obvious way. Minima in the spectra, however, give reasonable maximum ages for reheating and high-temperature maxima can be interpreted as minimum crystallization ages. High-temperature ages of microcline and albite that have not been reheated are approximately 10% younger than the known crystallization age. Apparently there are no domains in these feldspars that have retained radiogenic 40Ar quantitatively. Spectra from two diabase samples that contain significant quantities of excess argon might mistakenly be interpreted as spectra from reheated samples and do not give the age of emplacement. The 40Ar/39Ar age spectrum technique may be a potentially valuable tool for the study of geologic areas with complex histories, but the interpretation of age spectra from terrestrial samples seems to be more difficult than suggested by some previous studies. ?? 1971.

  10. Choosing Play Materials for Primary School Children (Ages 6-8)

    Science.gov (United States)

    Bronson, Martha

    2003-01-01

    Providing children with a variety of play materials at different levels of challenge and in a variety of interest areas responds to children's individual differences and needs in the classroom. In this book excerpt, the author lists materials for play in the categories social and fantasy; exploration and mastery; music, art, and movement; and…

  11. Effects of Thermal Aging on Material Properties, Stress Corrosion Cracking, and Fracture Toughness of AISI 316L Weld Metal

    Science.gov (United States)

    Lucas, Timothy; Forsström, Antti; Saukkonen, Tapio; Ballinger, Ronald; Hänninen, Hannu

    2016-08-01

    Thermal aging and consequent embrittlement of materials are ongoing issues in cast stainless steels, as well as duplex, and high-Cr ferritic stainless steels. Spinodal decomposition is largely responsible for the well-known "748 K (475 °C) embrittlement" that results in drastic reductions in ductility and toughness in these materials. This process is also operative in welds of either cast or wrought stainless steels where δ-ferrite is present. While the embrittlement can occur after several hundred hours of aging at 748 K (475 °C), the process is also operative at lower temperatures, at the 561 K (288 °C) operating temperature of a boiling water reactor (BWR), for example, where ductility reductions have been observed after several tens of thousands of hours of exposure. An experimental program was carried out in order to understand how spinodal decomposition may affect changes in material properties in Type 316L BWR piping weld metals. The study included material characterization, nanoindentation hardness, double-loop electrochemical potentiokinetic reactivation (DL-EPR), Charpy-V, tensile, SCC crack growth, and in situ fracture toughness testing as a function of δ-ferrite content, aging time, and temperature. SCC crack growth rates of Type 316L stainless steel weld metal under simulated BWR conditions showed an approximate 2 times increase in crack growth rate over that of the unaged as-welded material. In situ fracture toughness measurements indicate that environmental exposure can result in a reduction of toughness by up to 40 pct over the corresponding at-temperature air-tested values. Material characterization results suggest that spinodal decomposition is responsible for the degradation of material properties measured in air, and that degradation of the in situ properties may be a result of hydrogen absorbed during exposure to the high-temperature water environment.

  12. The effect of patient age on bone formation using a fully synthetic nanocrystalline bone augmentation material in maxillary sinus grafting.

    Science.gov (United States)

    Wolf, Michael; Wurm, Alexander; Heinemann, Friedhelm; Gerber, Thomas; Reichert, Christoph; Jäger, Andreas; Götz, Werner

    2014-01-01

    Maxillary sinus floor augmentation is a treatment that has been proposed for patients in whom the alveolar bone height is insufficient. This procedure is commonly used in patients aged 40 to 70 years and older. However, little information exists whether the factor of age might influence the outcome of augmentation procedures. The aim of this study was to investigate whether the patient's age has an effect on bone formation and incorporation in maxillary sinus floor augmentation procedures. A fully synthetic nanocrystalline bone augmentation material (NanoBone, Artoss) was used for sinus floor augmentation in patients with a subantral vertical bone height of at least 3 mm and maximum of 7 mm. After 7 months healing time, biopsy specimens were taken and were divided into two groups according to the patient's age. Exclusion criteria were poor general health (eg, severe renal/and or liver disease), history of a radiotherapy in the head region, chemotherapy at the time of surgical procedure, noncompensated diabetes mellitus, symptoms of a maxillary sinus disease, active periodontal or systemic diseases, smoking, and poor oral hygiene. Histologic analyses with hematoxylin-eosin stain were performed. Multinucleated osteoclast-like cells were identified by histochemical staining (tartrate-resistant acid phosphatase [TRAP]). Quantitative and age-dependent assessment of bone formation, residual bone grafting material, and soft tissue formation following sinus augmentation was performed using histomorphometric analysis and the Bonferroni adjustment of the Student t test. Twenty biopsy specimens from 17 patients were taken and divided into two groups according to age (group 1: 41 to 52 years; group 2: 66 to 71 years) containing 10 specimens each, which were analyzed in triplicate resulting in a total of 30 specimens per group. A regeneration process with varying amounts of newly formed bone surrounded by marrow-like tissue was present in all augmented regions. No signs of

  13. ACTIVE AGEING AND MATERIAL DEPRIVATION OF OLDER GENERATIONS IN EUROPE AND IN POLAND: HOW DO THEY INTERPLAY?

    Directory of Open Access Journals (Sweden)

    Jolanta Perek-Białas

    2015-07-01

    Full Text Available The active ageing concept includes domain of independent, healthy and secure living which includes financial aspects, measured by risk of poverty and material deprivation. The key questions of this paper are: how are the poverty indicators related to each other in the active ageing index?; in what ways are they related to some of the other indicators included in the index (such as employment? And which countries in Europe are “winners” and which are “losers” in this particular financial aspects based on the Active Ageing Index? Besides of this, the example of sub-national application of active ageing index for Poland was presented with showing relation of these financial indicators in the analysis.

  14. Effects of irradiation and thermal aging upon fatigue-crack growth behavior of reactor pressure boundary materials. [Neutrons

    Energy Technology Data Exchange (ETDEWEB)

    James, L. A.

    1978-10-01

    Two processes that have the potential to produce degradation in the properties of pressure boundary materials are neutron irradiation and long-time thermal aging. This paper uses linear-elastic fracture mechanics techniques to assess the effect of these two processes upon the fatigue-crack growth behavior of a number of alloys commonly employed in reactor pressure boundaries. The materials evaluated include ferritic steels, austenitic stainless steels, and nickel-base alloys typical of those employed in a number of reactor types including water-cooled, gas-cooled, and liquid-metal-cooled designs.

  15. Ultrasonic assessment of early age property development in hydrating cementitious materials

    Science.gov (United States)

    Wang, Xiaojun

    The internal structure (microstructure) of cementitious materials, such as cement paste, mortar and concrete, evolves over time because of cement hydration. The microstructure of the cementitious phase plays a very important role in determining the strength, the mechanical properties and the long-term durability of cementitious materials. Therefore any understanding of the strength gain and the long-term durability of cementitious materials requires a proper assessment of the microstructure of its cementitious phase. Current methods for evaluating the microstructure of the cement are invasive and primarily laboratory-based. These methods are not conducive for studying the pore structure changes in the first few hours after casting since the changes in microstructure occur on a time scale that is an order of magnitude faster than the time required for sample preparation. The primary objective of the research presented in this thesis is to contribute towards advancing the current state-of-the-art in assessing the microstructure of cementitious systems. An ultrasonic wave reflection technique which allows for real-time assessment of the porosity and the elastic modulus of cementitious materials is developed. The test procedure for monitoring changes in the amplitude of horizontally polarized ultrasonic shear waves from the surface of hydrating cement paste is presented. A theoretical framework based on a poro-elastic idealization of the hydrating cementitious material is developed for interpreting the ultrasonic reflection data. The poro-elastic representation of hydrating cementitious material is shown to provide simultaneous, realistic estimates of porosity and shear modulus for hydrating cement paste and mortar through setting and early strength gain. The porosity predicted by the poro-elastic representation is identical to the capillary water content within the cement paste predicted by Powers' model. The shear modulus of the poro-elastic skeleton was compares

  16. LWR aging management using a proactive approach to control materials degradation

    International Nuclear Information System (INIS)

    Bond, L.J.; Doctor, S.R.; Cumblidge, S.E.; Bruemmer, S.M.; Taylor, W.B.; Hull, A.B.; Malik, S.N.

    2009-01-01

    Material issues can be the limiting factor for the operation of nuclear power plants. There is growing interest in new and improved philosophies and methodologies for plant life management (PLiM), which include the migration from reliance on periodic inservice inspection to include condition-based maintenance. A further step in the development of plant management is the move from proactive responses based on ISI to become proactive, through the investigation of the potential for implementation of a proactive management of materials degradation (PMMD) program and its potential impact on the management of LWRs. (author)

  17. Aging material evaluation and studies by non-destructive techniques (AMES-NDT) - a European network project

    International Nuclear Information System (INIS)

    Dobmann, Gerd; Debarberis, Luigi; Coste, Jean-Francois

    2001-01-01

    This paper presents results obtained in a round-robin action organized in a concerted action of ten partners in the EURATOM program of the European Community. The objective of the research was to document the state of the art of available non-destructive testing (NDT) techniques in order to characterize material aging phenomena based on a reduction of Charpy-V energy and a shift in the fracture appearance transition temperature. Therefore, samples from the Japanese nuclear reactor pressure vessel JRQ-steel (ASMT Standard A533-B Class 1) have been thermally treated at 700 deg. C for 18 h with a subsequent water quenching. Besides micromagnetic and electromagnetic NDT, the positron annihilation technique, ultrasonic reverberation by using Laser ultrasonics and the thermo-electrical power have been applied to characterize the aged material states

  18. 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.

  19. Evaluation of Ultrasonic and Thermal Nondestructive Evaluation for the Characterization of Aging Degradation in Braided Composite Materials

    Science.gov (United States)

    Martin, Richard E.

    2010-01-01

    This paper examines the ability of traditional nondestructive evaluation (NDE) techniques to measure the degradation of braided polymer composite materials subjected to thermal-humidity cycling to simulate aging. A series of braided composite coupons were examined using immersion ultrasonic and pulsed thermography techniques in the as received condition. These same specimens were then examined following extended thermal-humidity cycling. Results of this examination did not show a significant change in the resulting (NDE) signals.

  20. [Parasite eggs identified in material from archaeological excavations in Ribe (the viking age) (author's transl)].

    Science.gov (United States)

    Nansen, P; Jorgensen, R J

    1977-06-01

    Eggs of Fasciola hepatica, Ascaris sp., Taenia sp., and Trichuris sp. have been demonstrated in archaeological excavations from the early viking period (750--800 A.D.) in Ribe, the oldest urban society of Denmark. The origin of the faecal material is discussed. The parasitological examinations are continued and extended.

  1. The effect of aging on the fracture toughness of esthetic restorative materials.

    Science.gov (United States)

    Bagheri, Rafat; Azar, Mohammad R; Tyas, Martin J; Burrow, Michael F

    2010-06-01

    To compare the fracture toughness (KIc) of tooth-colored restorative materials based on a four-point bending; to assess the effect of distilled water and a resin surface sealant (G-Coat Plus) on the resistance of the materials to fracture. Specimens were prepared from six materials: Quix Fil; Dyract (Dentsply), Freedom (SDI), Fuji VII (GC), Fuji IX (GC); Fuji II LC (GC). Fuji II LC and Fuji IX were tested both with and without applying G-Coat Plus (GC). The specimens were divided into the three groups which were conditioned in distilled water at 37 degrees C for 48 hours, 4 and 8 weeks. The specimens were loaded in a four-point bending test using a universal testing machine. The maximum load to specimen failure was recorded and the fracture toughness calculated. There were significant differences among most of the materials (P G-Coat Plus affected Fuji II LC positively while it had no effect on the Fuji IX.

  2. Simulated Aging and Characterization of Phase Change Materials for Thermal Management of Building Envelopes

    Science.gov (United States)

    2015-09-01

    materials of a PCM wall or ceiling panel. BioPCMat™ absorbs heat in the daytime and releases that heat during the night. The dimension of the typical...micrographs of Energain PCM samples showed evidence of melting and re- ERDC/CERL TR-15-23 32 crystallization ; however, there was no significant

  3. Measurement with corrugated tubes of early-age autogenous shrinkage of cement-based material

    DEFF Research Database (Denmark)

    Tian, Qian; Jensen, Ole Mejlhede

    2009-01-01

    The use of a special corrugated mould enables transformation of volume strain into horizontal, linear strain measurement in the fluid stage. This allows continuous measurement of the autogenous shrinkage of cement-based materials since casting, and also effectively eliminates unwanted influence...

  4. Listening Diary in the Digital Age: Students' Material Selection, Listening Problems, and Perceived Usefulness

    Science.gov (United States)

    Chen, Cheryl Wei-yu

    2016-01-01

    The current study reports on a group of Taiwanese college students' first-person diary accounts of their private, transactional listening activities outside the classroom. Issues related to students' material selection, listening problems, and perceived usefulness of keeping a listening diary were explored. It was found that most students chose…

  5. Control of Early Age Cracking in Concrete. Phase 4 and 5: Material Modelling, Continuum Approach

    DEFF Research Database (Denmark)

    Hauggaard-Nielsen, Anders Boe; Damkilde, Lars; Hansen, Per Freiesleben

    1997-01-01

    This report deals with numerical modelling of early age concrete. The hydration process giving the strength and stiffness development after casting is discussed. Several factors influence the progress of hydration such as the temperature level and the moisture activity. The factors are coupled an...

  6. Identification and Assessment of Material Models for Age-Related Degradation of Structures and Passive Components in Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Nie,J.; Braverman, J.; Hofmayer, C.; Kim, M. K.; Choi, I-K.

    2009-04-27

    When performing seismic safety assessments of nuclear power plants (NPPs), the potential effects of age-related degradation on structures, systems, and components (SSCs) should be considered. To address the issue of aging degradation, the Korea Atomic Energy Research Institute (KAERI) has embarked on a five-year research project to develop a realistic seismic risk evaluation system which will include the consideration of aging of structures and components in NPPs. Three specific areas that are included in the KAERI research project, related to seismic probabilistic risk assessment (PRA), are probabilistic seismic hazard analysis, seismic fragility analysis including the effects of aging, and a plant seismic risk analysis. To support the development of seismic capability evaluation technology for degraded structures and components, KAERI entered into a collaboration agreement with Brookhaven National Laboratory (BNL) in 2007. The collaborative research effort is intended to continue over a five year period with the goal of developing seismic fragility analysis methods that consider the potential effects of age-related degradation of SSCs, and using these results as input to seismic PRAs. In the Year 1 scope of work BNL collected and reviewed degradation occurrences in US NPPs and identified important aging characteristics needed for the seismic capability evaluations that will be performed in the subsequent evaluations in the years that follow. This information is presented in the Annual Report for the Year 1 Task, identified as BNL Report-81741-2008 and also designated as KAERI/RR-2931/2008. The report presents results of the statistical and trending analysis of this data and compares the results to prior aging studies. In addition, the report provides a description of U.S. current regulatory requirements, regulatory guidance documents, generic communications, industry standards and guidance, and past research related to aging degradation of SSCs. This report

  7. The effect of the accelerated aging on the mechanical properties of the PMMA denture base materials modified with itaconates

    Directory of Open Access Journals (Sweden)

    Spasojević Pavle M.

    2011-01-01

    Full Text Available This study evaluated the effect of accelerated ageing on the tensile strength, elongation at break, hardness and Charpy impact strength in commercial PMMA denture base material modified with di-methyl itaconate (DMI and di-n-butyl itaconate (DBI. The samples were prepared by modifying commercial formulation by addition of itaconates in the amounts of 2.5, 5, 7.5 and 10% by weight. After polymerization samples were characterized by FT-IR and DSC analysis while residual monomer content was determined by HPLC-UV. Accelerated ageing was performed at 70°C in water for periods of 7, 15 and 30 days. Tensile measurements were performed using Instron testing machine while the hardness of the polymerized samples was measured by Shore D method. The addition of itaconate significantly reduces the residual MMA. Even at the small amounts of added itaconates (2.5% the residual MMA content was reduced by 50%. The increase of itaconate content in the system leads to the decrease of residual MMA. It has been found that the addition of di-n-alkyl itaconates decreases the tensile strength, hardness and Charpy impact strength and increases elongation at break. Samples modified with DMI had higher values of tensile strength, hardness and Charpy impact strength compared to the ones modified with DBI. This is explained by the fact that DBI has longer side chain compared to DMI. After accelerated ageing during a 30 days period the tensile strength decreased for all the investigated samples. The addition of DMI had no effect on the material ageing and the values for the tensile strength of all of the investigated samples decreased around 20%, while for the samples modified with DBI, the increase of the amount of DBI in the polymerized material leads to the higher decrease of the tensile strength after the complete accelerated ageing period od 30 days, aulthough after the first seven days of the accelerated ageing the values of hardness have increased for all of the

  8. Predictive characterization of aging and degradation of reactor materials in extreme environments. Final report, December 20, 2013 - September 20, 2017

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Jianmin [Northwestern Univ., Evanston, IL (United States)

    2017-09-20

    Understanding of reactor material behavior in extreme environments is vital not only to the development of new materials for the next generation nuclear reactors, but also to the extension of the operating lifetimes of the current fleet of nuclear reactors. To this end, this project conducted a suite of unique experimental techniques, augmented by a mesoscale computational framework, to understand and predict the long-term effects of irradiation, temperature, and stress on material microstructures and their macroscopic behavior. The experimental techniques and computational tools were demonstrated on two distinctive types of reactor materials, namely, Zr alloys and high-Cr martensitic steels. These materials are chosen as the test beds because they are the archetypes of high-performance reactor materials (cladding, wrappers, ducts, pressure vessel, piping, etc.). To fill the knowledge gaps, and to meet the technology needs, a suite of innovative in situ transmission electron microscopy (TEM) characterization techniques (heating, heavy ion irradiation, He implantation, quantitative small-scale mechanical testing, and various combinations thereof) were developed and used to elucidate and map the fundamental mechanisms of microstructure evolution in both Zr and Cr alloys for a wide range environmental boundary conditions in the thermal-mechanical-irradiation input space. Knowledge gained from the experimental observations of the active mechanisms and the role of local microstructural defects on the response of the material has been incorporated into a mathematically rigorous and comprehensive three-dimensional mesoscale framework capable of accounting for the compositional variation, microstructural evolution and localized deformation (radiation damage) to predict aging and degradation of key reactor materials operating in extreme environments. Predictions from this mesoscale framework were compared with the in situ TEM observations to validate the model.

  9. Predictive characterization of aging and degradation of reactor materials in extreme environments. Final report, December 20, 2013 - September 20, 2017

    International Nuclear Information System (INIS)

    Qu, Jianmin

    2017-01-01

    Understanding of reactor material behavior in extreme environments is vital not only to the development of new materials for the next generation nuclear reactors, but also to the extension of the operating lifetimes of the current fleet of nuclear reactors. To this end, this project conducted a suite of unique experimental techniques, augmented by a mesoscale computational framework, to understand and predict the long-term effects of irradiation, temperature, and stress on material microstructures and their macroscopic behavior. The experimental techniques and computational tools were demonstrated on two distinctive types of reactor materials, namely, Zr alloys and high-Cr martensitic steels. These materials are chosen as the test beds because they are the archetypes of high-performance reactor materials (cladding, wrappers, ducts, pressure vessel, piping, etc.). To fill the knowledge gaps, and to meet the technology needs, a suite of innovative in situ transmission electron microscopy (TEM) characterization techniques (heating, heavy ion irradiation, He implantation, quantitative small-scale mechanical testing, and various combinations thereof) were developed and used to elucidate and map the fundamental mechanisms of microstructure evolution in both Zr and Cr alloys for a wide range environmental boundary conditions in the thermal-mechanical-irradiation input space. Knowledge gained from the experimental observations of the active mechanisms and the role of local microstructural defects on the response of the material has been incorporated into a mathematically rigorous and comprehensive three-dimensional mesoscale framework capable of accounting for the compositional variation, microstructural evolution and localized deformation (radiation damage) to predict aging and degradation of key reactor materials operating in extreme environments. Predictions from this mesoscale framework were compared with the in situ TEM observations to validate the model.

  10. Symbols, spaces and materiality: a transmission-based approach to Aegean Bronze Age ritual.

    OpenAIRE

    Briault, C.

    2005-01-01

    This thesis explores the transmission of ritual practices in the second millennium BC Aegean. In contrast to previous approaches, which often overlook gaps in the diachronic record, emphasising continuity in cult practice over very long timescales, it is argued here that through charting the spatial and temporal distributions of three broad material types (cult symbols, spaces and objects), it is possible to document the spread of cult practice over time and space, and, crucially, to monitor ...

  11. Accelerated Aging Experiments for Prognostics of Damage Growth in Composite Materials

    Science.gov (United States)

    2011-09-01

    builds on current understanding of fault modes in composites. This paper investigates faults in laminated ply composites. Such structures mainly...experiments where intermittent ground truth and in-situ characteristics are collected. Growth patterns are analyzed for damage types typical of laminated ...2: [0/902/45/-45/90], and Layup 3: [902/45/-45]2. Torayca T700G uni-directional carbon- prepreg material was used for 15.24 cm x 25.4 cm coupons with

  12. The origin of early age expansions induced in cementitious materials containing shrinkage reducing admixtures

    International Nuclear Information System (INIS)

    Sant, Gaurav; Lothenbach, Barbara; Juilland, Patrick; Le Saout, Gwenn; Weiss, Jason; Scrivener, Karen

    2011-01-01

    Studies on the early-age shrinkage behavior of cement pastes, mortars, and concretes containing shrinkage reducing admixtures (SRAs) have indicated these mixtures frequently exhibit an expansion shortly after setting. While the magnitude of the expansion has been noted to be a function of the chemistry of the cement and the admixture dosage; the cause of the expansion is not clearly understood. This investigation uses measurements of autogenous deformation, X-ray diffraction, pore solution analysis, thermogravimetry, and scanning electron microscopy to study the early-age properties and describe the mechanism of the expansion in OPC pastes made with and without SRA. The composition of the pore solution indicates that the presence of the SRA increases the portlandite oversaturation level in solution which can result in higher crystallization stresses which could lead to an expansion. This observation is supported by deformation calculations for the systems examined.

  13. Catalyst Stability Benchmarking for the Oxygen Evolution Reaction: The Importance of Backing Electrode Material and Dissolution in Accelerated Aging Studies.

    Science.gov (United States)

    Geiger, Simon; Kasian, Olga; Mingers, Andrea M; Nicley, Shannon S; Haenen, Ken; Mayrhofer, Karl J J; Cherevko, Serhiy

    2017-09-18

    In searching for alternative oxygen evolution reaction (OER) catalysts for acidic water splitting, fast screening of the material intrinsic activity and stability in half-cell tests is of vital importance. The screening process significantly accelerates the discovery of new promising materials without the need of time-consuming real-cell analysis. In commonly employed tests, a conclusion on the catalyst stability is drawn solely on the basis of electrochemical data, for example, by evaluating potential-versus-time profiles. Herein important limitations of such approaches, which are related to the degradation of the backing electrode material, are demonstrated. State-of-the-art Ir-black powder is investigated for OER activity and for dissolution as a function of the backing electrode material. Even at very short time intervals materials like glassy carbon passivate, increasing the contact resistance and concealing the degradation phenomena of the electrocatalyst itself. Alternative backing electrodes like gold and boron-doped diamond show better stability and are thus recommended for short accelerated aging investigations. Moreover, parallel quantification of dissolution products in the electrolyte is shown to be of great importance for comparing OER catalyst feasibility. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Material Resources and Population Health: Disadvantages in Health Care, Housing, and Food Among Adults Over 50 Years of Age

    Science.gov (United States)

    Soldo, Beth J.; Pagán, José A.; McCabe, John; deBlois, Madeleine; Field, Samuel H.; Asch, David A.; Cannuscio, Carolyn

    2009-01-01

    Objectives. We examined associations between material resources and late-life declines in health. Methods. We used logistic regression to estimate the odds of declines in self-rated health and incident walking limitations associated with material disadvantages in a prospective panel representative of US adults aged 51 years and older (N = 15 441). Results. Disadvantages in health care (odds ratio [OR] = 1.39; 95% confidence interval [CI] = 1.23, 1.58), food (OR = 1.69; 95% CI = 1.29, 2.22), and housing (OR = 1.20; 95% CI = 1.07, 1.35) were independently associated with declines in self-rated health, whereas only health care (OR = 1.43; 95% CI = 1.29, 1.58) and food (OR = 1.64; 95% CI = 1.31, 2.05) disadvantage predicted incident walking limitations. Participants experiencing multiple material disadvantages were particularly susceptible to worsening health and functional decline. These effects were sustained after we controlled for numerous covariates, including baseline health status and comorbidities. The relations between health declines and non-Hispanic Black race/ethnicity, poverty, marital status, and education were attenuated or eliminated after we controlled for material disadvantage. Conclusions. Material disadvantages, which are highly policy relevant, appear related to health in ways not captured by education and poverty. Policies to improve health should address a range of basic human needs, rather than health care alone. PMID:19890175

  15. Mechanism and materialism British natural philosophy in the age of reason

    CERN Document Server

    Schofield, Robert E

    1970-01-01

    Robert Schofield explores the rational elements of British experimental natural philosophy in the 18th century by tracing the influence of two opposing concepts of the nature of matter and its action-mechanism and materialism. Both concepts rested on the Newtonian interpretation of their proponents, although each developed more or less independently. By integrating the developments in all the areas of experimental natural philosophy, describing their connections and the influences of Continental science, natural theology, and to a lesser degree social and institutional changes, the author dem

  16. Study of Polymer Material Aging by Laser Mass Spectrometry, UV-Visible Spectroscopy, and Environmental Scanning Electron Microscopy

    Directory of Open Access Journals (Sweden)

    Junien Exposito

    2007-01-01

    Full Text Available Dyed natural rubber (NR and styrene butadiene rubber (SBR, designed for outdoor applications, were exposed to an accelerated artificial aging in xenon light. The aging results in the deterioration of the exposed surface material properties. The ability of dyed polymers to withstand prolonged sunlight exposure without fading or undergoing any physical deterioration is largely determined not only by the photochemical characteristics of the absorbing dyestuff itself but also by the polymer structure and fillers. Results obtained by laser mass spectrometry, UV-visible spectroscopy, and environmental scanning electron microscopy indicate that dyed filled NR and SBR samples behave differently during the photo-oxidation. The fading of the dyed polymers was found to be promoted in the NR sample. This can be correlated with LDI-FTICRMS results, which show the absence of [M-H]− orange pigment pseudomolecular ion and also its fragment ions after aging. This is confirmed by both EDX and UV/Vis spectroscopy. EDX analysis indicates a concentration of chlorine atoms, which can be considered as a marker of orange pigment or its degradation products, only at the surface of SBR flooring after aging. Reactivity of radicals formed during flooring aging has been studied and seems to greatly affect the behavior of such organic pigments.

  17. The influence of age on the composting rate of organic material by Eisenia fetida (Oligochaeta

    Directory of Open Access Journals (Sweden)

    Editorial Office

    1995-07-01

    Full Text Available One of the main objectives of a vermicomposting plant is to achieve a maximum composting rate of organic waste. Apart from population densities, substrate characteristics and environmental factors, age structure of the population is expected to affect the rate of composting. The composting rate of worms was studied in the laboratory under optimal conditions over a period of 55 days. Growth and sexual maturity were monitored as well as the composting rate during various stages of the life-cycle of Eisenia fetida. The composting rate was initially slow and reached a maximum peak when the worms were pre-clitellate.

  18. Investigation of strain heterogeneities by laser scanning extensometry in strain ageing materials: application to zirconium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Graff, S.; Forest, S.; Strudel, J.L. [Centre des Materiaux / UMR 7633, Ecole des Mines de Paris / CNRS, BP 87, 91003 Evry (France); Dierke, H.; Neuhauser, H. [Institut fur Physik der Kondensierten Materie, 38106 Braunschweig (Germany); Prioul, C. [MSSMAT, Ecole Centrale Paris, Grande Voie des Vignes, 92295 Chatenay-Malabry (France); Bechade, J.L. [SRMA, CEA Saclay, 91191 Gif sur Yvette (France)

    2005-07-01

    Laser scanning extensometry was used to detect and characterize propagating plastic instabilities such as the Luders bands at the millimeter scale. Spatio-temporal plastic heterogeneities are due to either static or dynamic strain ageing (SSA and DSA) phenomena. Regarding zirconium alloys, different type of heterogeneities were observed: their features strongly depended on mechanical test conditions. In one case, they appeared to be non propagating but preserved along the stress-strain curve and were associated with SSA effects such as stress peaks after relaxation periods or after unloading steps with waiting times. In other case, they appeared as non propagating but were not associated with SSA effects. (authors)

  19. Investigation of strain heterogeneities by laser scanning extensometry in strain ageing materials: application to zirconium alloys

    International Nuclear Information System (INIS)

    Graff, S.; Forest, S.; Strudel, J.L.; Dierke, H.; Neuhauser, H.; Prioul, C.; Bechade, J.L.

    2005-01-01

    Laser scanning extensometry was used to detect and characterize propagating plastic instabilities such as the Luders bands at the millimeter scale. Spatio-temporal plastic heterogeneities are due to either static or dynamic strain ageing (SSA and DSA) phenomena. Regarding zirconium alloys, different type of heterogeneities were observed: their features strongly depended on mechanical test conditions. In one case, they appeared to be non propagating but preserved along the stress-strain curve and were associated with SSA effects such as stress peaks after relaxation periods or after unloading steps with waiting times. In other case, they appeared as non propagating but were not associated with SSA effects. (authors)

  20. Materials

    CSIR Research Space (South Africa)

    Van Wyk, Llewellyn V

    2009-02-01

    Full Text Available . It is generally included as part of a structurally insulated panel (SIP) where the foam is sandwiched between external skins of steel, wood or cement. Cement composites Cement bonded composites are an important class of building materials. These products... for their stone buildings, including the Egyptians, Aztecs and Inca’s. As stone is a very dense material it requires intensive heating to become warm. Rocks were generally stacked dry but mud, and later cement, can be used as a mortar to hold the rocks...

  1. Effectiveness of integrated science instructional material on pressure in daily life theme to improve digital age literacy of students

    Science.gov (United States)

    Asrizal; Amran, A.; Ananda, A.; Festiyed; Khairani, S.

    2018-04-01

    Integrated science learning and literacy skills are relevant issues in Indonesian’s education. However, the use of the integrated science learning and the integration of literacy in learning cannot be implemented well. An alternative solution of this problem is to develop integrated science instructional material on pressure in daily life theme by integrating digital age literacy. Purpose of research is to investigate the effectiveness of the use of integrated science instructional material on pressure in daily life theme to improve knowledge competence, attitudes competence and literacy skills of students. This research was a part of development research which has been conducted. In the product testing stage of this research and development was used before and after design of treatment for one sample group. Instruments to collect the data consist of learning outcomes test sheet, attitude observation sheet, and performance assessment sheet of students. Data analysis techniques include descriptive statistics analysis, normality test, homogeneity test, and paired comparison test. Therefore, the important result of research is the use of integrated science instructional material on pressure in daily life theme is effective in scientific approach to improve knowledge competence, attitudes competence, and digital age literacy skills of grade VIII students at 95% confidence level.

  2. Simulation and experiment of thermal energy management with phase change material for ageing LiFePO4 power battery

    International Nuclear Information System (INIS)

    Rao Zhonghao; Wang Shuangfeng; Zhang Guoqing

    2011-01-01

    Highlights: → We study the thermal energy management performance of ageing LiFePO 4 power battery. → 3-D modules of single cell and battery pack are formulated according to the experimental results. → Thermal resistance in the battery cell leaded to an inevitable temperature difference. → It is necessary to improve the thermal conductivity and lower the melting point of phase change material. → Thermal conductivity of phase change material and battery exist an effective proportion. - Abstract: Thermal energy management performance of ageing commercial rectangular LiFePO 4 power batteries using phase change material (PCM) and thermal behavior related to thermal conductivity between the PCM and the cell are discussed in this paper. The heat sources are simplified according to the experimental results of the cells discharged at 35 A (∼5 C). 3-D modules of a single cell and battery pack are formulated, respectively. The results show that the thermal resistance in the cell leads to an inevitable temperature difference. It is necessary to improve the thermal conductivity and to lower the melting point of the PCM for heat transfer enhancement. The PCM with a melting point lower than 45 deg. C will be more effective for heat dissipation, with a desired maximum temperature below 50 deg. C. The temperature difference in the whole unit before PCM melting will be decreased significantly. In addition, a proper k PCM :k c is necessary for a well designed battery thermal energy management system.

  3. Explaining the impact of poverty on old-age frailty in Europe: material, psychosocial and behavioural factors.

    Science.gov (United States)

    Stolz, Erwin; Mayerl, Hannes; Waxenegger, Anja; Freidl, Wolfgang

    2017-12-01

    Previous research found poverty to be associated with adverse health outcomes among older adults but the factors that translate low economic resources into poor physical health are not well understood. The goal of this analysis was to assess the impact of material, psychosocial, and behavioural factors as well as education in explaining the poverty-health link. In total, 28 360 observations from 11 390 community-dwelling respondents (65+) in the Survey of Health, Ageing and Retirement in Europe (2004-13, 10 countries) were analysed. Multilevel growth curve models were used to assess the impact of combined income and asset poverty risk on old-age frailty (frailty index) and associated pathway variables. In total, 61.8% of the variation of poverty risk on frailty level was explained by direct and indirect effects. Results stress the role of material and particularly psychosocial factors such as perceived control and social isolation, whereas the role of health behaviour was negligible. We suggest to strengthen social policy and public health efforts in order to fight poverty and its deleterious health effects from early age on as well as to broaden the scope of interventions with regard to psychosocial factors. © The Author 2017. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.

  4. 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)

  5. Book Review: Knowledge in the Age of Digital Capitalism: An Introduction to Cognitive Materialism by Mariano Zukerfeld

    Directory of Open Access Journals (Sweden)

    Rainer Zimmermann

    2018-02-01

    Full Text Available Rainer E. Zimmermann reviews Mariano Zukerfeld's Knowledge in the Age of Digital Capitalism. An Introduction to Cognitive Materialism, University of Westminster Press, London, 2017, 272 pp., paperback and open access, gratis e-book. There are several aspects of innovative thoughts in this text as to recent developments, in particular concerning the manifold occasions of more or less hidden layers of exploitation originating in the use of digital technology, and mainly based on un-remunerated activities. All this speaks very much in favour of reading this book; only minor objections have to be made that should not prevent a profitable reading.

  6. Effect of varying core thicknesses and artificial aging on the color difference of different all-ceramic materials.

    Science.gov (United States)

    Dikicier, Sibel; Ayyildiz, Simel; Ozen, Julide; Sipahi, Cumhur

    2014-11-01

    Clinicians should reserve all-ceramics with high translucency for clinical applications in which high-level esthetics are required. Furthermore, it is unclear whether a correlation exists between core thickness and color change. The aim of this study was to examine the effects of different core thicknesses and artificial aging on the color stability of three all-ceramic systems. Ninety disc-shaped cores with different thicknesses (0.5 mm, 0.8 mm and 1.0 mm) were prepared from three all-ceramic systems, In-Ceram Alumina (IC), IPS e.max Press (EM) and Katana (K). The colors of the samples were measured with a spectrophotometer and the color parameters (L*, a*, b*, ΔE) were calculated according to the CIE L*a*b* (Commission Internationale de L'Eclairage) color system before and after aging. The effects of aging on color parameters were statistically significant (p artificial aging affected color stability of the all-ceramic materials tested.

  7. Accelerated Aging Experiments for Prognostics of Damage Growth in Composite Materials

    Science.gov (United States)

    Saxena, Abhinav; Goebel, Kai Frank; Larrosa, Cecilia C.; Janapati, Vishnuvardhan; Roy, Surajit; Chang, Fu-Kuo

    2011-01-01

    Composite structures are gaining importance for use in the aerospace industry. Compared to metallic structures their behavior is less well understood. This lack of understanding may pose constraints on their use. One possible way to deal with some of the risks associated with potential failure is to perform in-situ monitoring to detect precursors of failures. Prognostic algorithms can be used to predict impending failures. They require large amounts of training data to build and tune damage model for making useful predictions. One of the key aspects is to get confirmatory feedback from data as damage progresses. These kinds of data are rarely available from actual systems. The next possible resource to collect such data is an accelerated aging platform. To that end this paper describes a fatigue cycling experiment with the goal to stress carbon-carbon composite coupons with various layups. Piezoelectric disc sensors were used to periodically interrogate the system. Analysis showed distinct differences in the signatures of growing failures between data collected at conditions. Periodic X-radiographs were taken to assess the damage ground truth. Results after signal processing showed clear trends of damage growth that were correlated to damage assessed from the X-ray images.

  8. Positron age-momentum correlation in metal oxide powders as catalytic materials

    International Nuclear Information System (INIS)

    Kishimoto, Y.; Ito, K.; Tanigawa, S.; Tsuda, N.

    1982-01-01

    Annihilation characteristics of positrons in fine particles of various types of metal oxides (MgO, SiO 2 , #betta#-Al 2 O 3 , TiO 2 , ZnO and NiO) were studied by the two parameter correlation measurements between the positron age and the momentum of annihilating pairs. It was found that the momentum dependence of lifetime can be classified into three types, that is, the bell shape tau-E relation (Type I : #betta#-Al 2 O 3 ), the W-like one (Type II : ZnO, NiO, MgO and TiO 2 ) and the M-like one (Type III : SiO 2 ). This variation may be due to the difference in the formation and reaction of positroniums at the surface of fine particles of different oxides reflecting the nature of acid points or basic points in catalytic reactions. Particularly, the frequent occurrence of the conversion process of ortho-Ps was observed. (Auth.)

  9. 'Age' Determination of Irradiated Materials Utilizing Inductively Coupled Plasma Mass Spectrometric (ICP-MS) Detection

    International Nuclear Information System (INIS)

    Sommers, James; Giglio, Jeffrey J.; Cummings, Daniel; Carney, Kevin P.

    2009-01-01

    A gas pressurized extraction chromatography (GPEC) system has been developed to perform elemental separations on radioactive samples to determine total and isotopic compositions of Cs and Ba from an irradiated salt sample, fuel sample and two sealed radiation sources. The separation is necessary to remove isobaric interferences in the determination of 137Cs, 135Cs, 137Ba, 135Ba, which are used to determine the age of a sample from radioactive decay or purification. The micro-column extraction chromatography system employs compressed nitrogen to move liquid through the system, compared to gravity or pumped liquids that are typically used for separations. The use of compressed gas allows for accurate and precise recovery of all liquids put into the chromatography system, enabling very accurate dilutions. The use of a small analytical column permits the use of very small amounts of liquids to be used. As a benefit, the amount of radiological waste that is generated in the separation process is minimized. For this work, a commercially available Sr-Resin(trademark) was used to perform the separation for the above mentioned analytes. The column consists of a 7 inch piece of 1/16 in. O.D. x 0.030 in I.D. Teflon(trademark) tubing having an internal volume of 81 (micro)L. To this column, 49 mg of resin was added. The columns are re-usable after regeneration with 3 M HNO3. All samples were separated using batch collection, although real time analysis is possible with the current experimental design. A 1 % acetic acid solution was determined to be the best extractant for Ba. A flow rate of 0.1 mL/min was determined to be optimal for the separation of Ba. Complete recovery of the Cs and Ba was achieved, within the systematic error of the experiments.

  10. PLANETARY-SCALE STRONTIUM ISOTOPIC HETEROGENEITY AND THE AGE OF VOLATILE DEPLETION OF EARLY SOLAR SYSTEM MATERIALS

    Energy Technology Data Exchange (ETDEWEB)

    Moynier, Frederic; Podosek, Frank A. [Department of Earth and Planetary Science and McDonnell Center for Space Sciences, Washington University, St. Louis, MO 63130 (United States); Day, James M. D. [Geosciences Research Division, Scripps Institution of Oceanography, La Jolla, CA 92093-0244 (United States); Okui, Wataru; Yokoyama, Tetsuya [Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo 152-8551 (Japan); Bouvier, Audrey [Department of Earth Sciences, University of Minnesota, Minneapolis, MN 55455-0231 (United States); Walker, Richard J., E-mail: moynier@levee.wustl.edu, E-mail: fap@levee.wustl.edu, E-mail: jmdday@ucsd.edu, E-mail: rjwalker@umd.edu, E-mail: okui.w.aa@m.titech.ac.jp, E-mail: tetsuya.yoko@geo.titech.ac.jp, E-mail: abouvier@umn.edu [Department of Geology, University of Maryland, College Park, MD 20742 (United States)

    2012-10-10

    Isotopic anomalies in planetary materials reflect both early solar nebular heterogeneity inherited from presolar stellar sources and processes that generated non-mass-dependent isotopic fractionations. The characterization of isotopic variations in heavy elements among early solar system materials yields important insight into the stellar environment and formation of the solar system, and about initial isotopic ratios relevant to long-term chronological applications. One such heavy element, strontium, is a central element in the geosciences due to wide application of the long-lived {sup 87}Rb-{sup 87}Sr radioactive as a chronometer. We show that the stable isotopes of Sr were heterogeneously distributed at both the mineral scale and the planetary scale in the early solar system, and also that the Sr isotopic heterogeneities correlate with mass-independent oxygen isotope variations, with only CI chondrites plotting outside of this correlation. The correlation implies that most solar system material formed by mixing of at least two isotopically distinct components: a CV-chondrite-like component and an O-chondrite-like component, and possibly a distinct CI-chondrite-like component. The heterogeneous distribution of Sr isotopes may indicate that variations in initial {sup 87}Sr/{sup 86}Sr of early solar system materials reflect isotopic heterogeneity instead of having chronological significance, as interpreted previously. For example, given the differences in {sup 84}Sr/{sup 86}Sr between calcium aluminum inclusions and eucrites ({epsilon}{sup 84}Sr > 2), the difference in age between these materials would be {approx}6 Ma shorter than previously interpreted, placing the Sr chronology in agreement with other long- and short-lived isotope systems, such as U-Pb and Mn-Cr.

  11. Ultrasound monitoring of applied forcing, material ageing, and catastrophic yield of crustal structures

    Directory of Open Access Journals (Sweden)

    G. P. Gregori

    2007-11-01

    Full Text Available A new kind of data analysis is discussed – and a few case histories of actual application are presented – concerning the physical information attainable by acoustic emission (AE records in geodynamically active or volcanic areas. The previous analyses of such same kind of observations were reported in several papers appeared in the last few years, and here briefly recalled. They are concerned with the inference of the forcing ("F" acting on the physical system, and on the ageing ("T" or fatigue of its "solid" structures. The new analysis here discussed deals with the distinction between a state of applied stress ("hammer regime", compared to state of "recovery regime" of the system while it seeks a new equilibrium state after having been perturbed. For instance, in the case of a seismic event – and according to some kind of almost intuitive argument – the "hammer regime" is the phenomenon leading to the main shock, while the "recovery regime" deals with the well known aftershocks. Such same intuitive inference, however, can be investigated by a much more formal algorithm, aimed at envisaging the minor changes of the behaviour of the system, during its history and during its present dynamic evolution. As a demonstrative application, detailed consideration is given of AE records – each one lasting for a few years – collected on the Italian peninsula vs. records collected on the Kefallinìa Island (western Greece. Such two areas are well known being characterised by some great comparative difference in their respective tectonic setting. When considering planetary scale phenomena, they appear comparatively very close to each other. Hence, they are likely being presumably affected by similar large-scale external actions, although they ought to be expected to respond in some completely different way. Such facts are clearly manifested by some substantially different AE responses of the local crustal

  12. Toxicity of functional nano-micro zinc oxide tetrapods: impact of cell culture conditions, cellular age and material properties.

    Science.gov (United States)

    Papavlassopoulos, Heike; Mishra, Yogendra K; Kaps, Sören; Paulowicz, Ingo; Abdelaziz, Ramzy; Elbahri, Mady; Maser, Edmund; Adelung, Rainer; Röhl, Claudia

    2014-01-01

    With increasing production and applications of nanostructured zinc oxide, e.g., for biomedical and consumer products, the question of safety is getting more and more important. Different morphologies of zinc oxide structures have been synthesized and accordingly investigated. In this study, we have particularly focused on nano-micro ZnO tetrapods (ZnO-T), because their large scale fabrication has been made possible by a newly introduced flame transport synthesis approach which will probably lead to several new applications. Moreover, ZnO-T provide a completely different morphology then classical spherical ZnO nanoparticles. To get a better understanding of parameters that affect the interactions between ZnO-T and mammalian cells, and thus their biocompatibility, we have examined the impact of cell culture conditions as well as of material properties on cytotoxicity. Our results demonstrate that the cell density of fibroblasts in culture along with their age, i.e., the number of preceding cell divisions, strongly affect the cytotoxic potency of ZnO-T. Concerning the material properties, the toxic potency of ZnO-T is found to be significantly lower than that of spherical ZnO nanoparticles. Furthermore, the morphology of the ZnO-T influenced cellular toxicity in contrast to surface charges modified by UV illumination or O2 treatment and to the material age. Finally, we have observed that direct contact between tetrapods and cells increases their toxicity compared to transwell culture models which allow only an indirect effect via released zinc ions. The results reveal several parameters that can be of importance for the assessment of ZnO-T toxicity in cell cultures and for particle development.

  13. Micromechanical modelling of heterogeneous materials in transient conditions: contributions for the study of the ageing of structural components under service

    International Nuclear Information System (INIS)

    Masson, R.

    2010-01-01

    The modelling of the mechanical behaviour of structural materials is increasingly based on microstructural parameters. Within this framework, homogenisation methods have the advantage of providing deductive methods which, starting from the properties and space distribution of each constituent, deduce the effective properties of the heterogeneous material. Nevertheless, many applications make still difficult the use of homogenisation methods. It is in particular the case of structural materials presenting elastic-viscoplastic behaviours and subjected to both non-monotone and ageing loadings. To progress on the treatment by homogenisation of these useful situations constitutes precisely the main idea of the various contributions presented in this work.For linear elasticity, new expressions for the computation of the Eshelby tensor are first of all established in order to improve the efficiency of homogenisation methods usually used. Always for linear behaviours but now viscoelastic, various approximations associated with the use of the theorem of correspondence are studied and compared. The equivalence of one of these approximations (the so-called 'collocation method') with an internal variables formulation of the effective behaviour is shown. This internal variables formulation leads to exact results in some situations and strongly simplifies the treatment of ageing linear viscoelastic behaviours. In the case of elastic-viscoplastic behaviours, is added to the previous difficulty (viscoelastic coupling) that of the treatment of nonlinear behaviour. Comparisons made between various families of estimates make it possible to determine the effects of the various approximations needed to deal with these nonlinearities. An improvement is also proposed and implemented in a particular case while the extension of this internal variable formulation to nonlinear behaviours is discussed. Finally, full-field computations of microstructures are also tackled by considering the

  14. Characterization of vacancy type defects in Electronic Materials by Positron Lifetime and Age-Momentum Correlation Spectroscopy

    Science.gov (United States)

    Suzuki, Ryoichi; Ohdaira, Toshiyuki

    2002-03-01

    Positron annihilation spectroscopy is known to be sensitive to vacancy type defects. At the National Institute of Advanced Industrial Science and Technology (AIST) Japan, the authors have developed a measurement system which enables us to perform depth-selective positron annihilation lifetime spectroscopy (PALS) and positron age-momentum correlation (AMOC) spectroscopy with an intense slow positron beam. PALS gives us information on the size of vacancies whereas AMOC gives us information on not only vacancy sizes but also impurities or chemical environments. Using this system, we have carried out defect characterization experiments on various electronic materials, e.g. ion implanted Si, SiO2/Si, MOS, CVD or SOD (spin-on-dielectric) grown low dielectric insulator films, etc.

  15. Initial laboratory studies into the chemical and radiological aging of organic materials in underground storage tanks at the Hanford Complex

    International Nuclear Information System (INIS)

    Samuels, W.D.; Camaioni, D.M.; Babad, H.

    1994-01-01

    The underground storage tanks at the Hanford Complex contain wastes generated over many years from plutonium production and recovery processes, and mixed wastes from radiological degradation processes. The chemical changes of the organic materials used in the extraction processes have a direct bearing on several specific safety issues, including potential energy releases from these tanks. The major portion of organic materials that have been added to the tanks consists of tributyl phosphate, dibutyl phosphate, butyl alcohol, hexone (methyl isobutyl ketone), normal paraffin hydrocarbons (NPH), ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriadetic acid (HEDTA), other complexants, and lesser quantities of ion exchange polymers and minor organic compounds. A study of how thermal and radiological processes that may have changed the composition of organic tanks constituents has been initiated after a review of the open literature revealed little information was available about the rates and products of these processes under basic pH conditions. This paper will detail the initial findings as they relate to gas generation, e.g. H 2 , CO, NH 3 , CH 4 , and to changes in the composition of the organic and inorganic components brought about by ''Aging'' processes

  16. Research note: Mapping spatial patterns in sewer age, material, and proximity to surface waterways to infer sewer leakage hotspots

    Science.gov (United States)

    Hopkins, Kristina G.; Bain, Daniel J.

    2018-01-01

    Identifying areas where deteriorating sewer infrastructure is in close proximity to surface waterways is needed to map likely connections between sewers and streams. We present a method to estimate sewer installation year and deterioration status using historical maps of the sewer network, parcel-scale property assessment data, and pipe material. Areas where streams were likely buried into the sewer system were mapped by intersecting the historical stream network derived from a 10-m resolution digital elevation model with sewer pipe locations. Potential sewer leakage hotspots were mapped by identifying where aging sewer pipes are in close proximity (50-m) to surface waterways. Results from Pittsburgh, Pennsylvania (USA), indicated 41% of the historical stream length was lost or buried and the potential interface between sewers and streams is great. The co-location of aging sewer infrastructure (>75 years old) near stream channels suggests that 42% of existing streams are located in areas with a high potential for sewer leakage if sewer infrastructure fails. Mapping the sewer-stream interface provides an approach to better understand areas were failing sewers may contribute a disproportional amount of nutrients and other pathogens to surface waterways.

  17. Performance and Ageing Robustness of Graphite/NMC Pouch Prototypes Manufactured through Eco-Friendly Materials and Processes.

    Science.gov (United States)

    Loeffler, Nicholas; Kim, Guk-T; Passerini, Stefano; Gutierrez, Cesar; Cendoya, Iosu; De Meatza, Iratxe; Alessandrini, Fabrizio; Appetecchi, Giovanni B

    2017-09-22

    Graphite/lithium nickel-manganese-cobalt oxide (NMC), stacked pouch cells with nominal capacity of 15-18 Ah were designed, developed, and manufactured for automotive applications in the frame of the European Project GREENLION. A natural, water-soluble material was used as the main electrode binder, thus allowing the employment of H 2 O as the only processing solvent. The electrode formulations were developed, optimized, and upscaled for cell manufacturing. Prolonged cycling and ageing tests revealed excellent capacity retention and robustness toward degradation phenomena. For instance, above 99 % of the initial capacity is retained upon 500 full charge/discharge cycles, corresponding to a fading of 0.004 % per cycle, and about 80 % of the initial capacity is delivered after 8 months ageing at 45 °C. The stacked soft-packaged cells have shown very reproducible characteristics and performance, reflecting the goodness of design and manufacturing. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Iron Age Material Culture in South Asia – Analysis and Context of Recently Discovered Slag Sites in Northwest Kashmir (Baramulla District in India

    Directory of Open Access Journals (Sweden)

    Mumtaz A Yatoo

    2015-03-01

    Full Text Available This paper deals with presence or absence of Iron Age material culture and explores the development of Iron Age in northwest Kashmir (Baramulla District. It has been noted from the previous surveys that a chronological gap existed (c. 1000 BCE – 100 CE, which roughly equates to the Iron Age in Kashmir (Yatoo 2005; Yatoo 2012. Furthermore, considering that there is very little evidence of Iron Age material culture from the few excavated (or explored sites in Kashmir, there is a debate about the very presence of Iron Age in Kashmir. The little information we have about Iron Age material culture from key sites in Kashmir (such as a few sherds of NBPW, some iron artefacts and slag at one site, has been largely dismissed as imports and lacked serious attention by scholars. It was therefore difficult to build any comparisons in the material culture for the present study. Instead the Iron Age material culture in other parts of South Asia, such as the Indian plains and northern regions of Pakistan, are discussed, as these regions have documented evidence of iron and its associated material culture but very few have archaeometallurgical evidence. Furthermore, Kashmir historically had communication links with these regions in South Asia since the early third millennium BCE until the 10th century CE, so we might expect some contact during the period of early iron production and use. Therefore, one key issue for archaeology in northwest Kashmir in this paper is to understand the link between the newly discovered slag and tuyeres with the key sites in Kashmir and in South Asia; and a further key issue is to determine whether or not there was a distinct Iron Age in north west Kashmir (or whole of Kashmir, or whether the few recovered iron artefacts from key sites of Kashmir are indeed all imports.

  19. Bacterial biodegradation of melamine-contaminated aged soil: influence of different pre-culture media or addition of activation material.

    Science.gov (United States)

    Hatakeyama, Takashi; Takagi, Kazuhiro

    2016-08-01

    This study aimed to investigate the biodegrading potential of Arthrobacter sp. MCO, Arthrobacter sp. CSP, and Nocardioides sp. ATD6 in melamine-contaminated upland soil (melamine: approx. 10.5 mg/kg dry weight) after 30 days of incubation. The soil sample used in this study had undergone annual treatment of lime nitrogen, which included melamine; it was aged for more than 10 years in field. When R2A broth was used as the pre-culture medium, Arthrobacter sp. MCO could degrade 55 % of melamine after 30 days of incubation, but the other strains could hardly degrade melamine (approximately 25 %). The addition of trimethylglycine (betaine) in soil as an activation material enhanced the degradation rate of melamine by each strain; more than 50 % of melamine was degraded by all strains after 30 days of incubation. In particular, strain MCO could degrade 72 % of melamine. When the strains were pre-cultured in R2A broth containing melamine, the degradation rate of melamine in soil increased remarkably. The highest (72 %) melamine degradation rate was noted when strain MCO was used with betaine addition.

  20. Contribution to concrete modelling towards aging and durability: interactions between creep deformations and non-linear behaviour of the material

    International Nuclear Information System (INIS)

    Berthollet, A.

    2003-10-01

    Concrete structures are examined during their lifetime and often present important cracking states, which can progress with time and lead to change the structural behavior. The civil engineering works that the main function corresponds to protection's wall are very sensitive to this damage and its evolution. The growth of the time - dependent cracks represents an aging pathology linked with interaction between creep mechanism and the non-linear behavior of the material. In this thesis, a modeling for these mechanisms and their coupling are proposed. It based on creep strains analysis under different load levels, on the influence of the rate effect to the mechanical behavior. A stress limit is put on prominent manner, where beyond it, the creep - cracking interaction becomes important with the introduction of the ultimate tertiary creep kinetic. This level of strength is identified for infinitely slow loading rates and is also called intrinsic strength. It defines the limit on this side the viscous behavior of the cement paste limits the irreversibility processes as cracking. Thus, a constitutive law of viscoelastic - viscoplastic behavior with a high coupling between the cracking mechanism and the creep strains is proposed. The developments of the model are built on DUVAUT - LIONS approach integrated a generalized MAXWELL chain model. For one part, the viscoelastic behavior translates the creep mechanism under low stresses. For a second part, it associated with the viscoplastic behavior, which allows introducing both creep effect under high stresses and rate effect acting on micro-cracked zones. The cracking mechanism is described throughout a plasticity theory with multi-criteria, which induce a property of anisotropy for hardening. Qualitatively, ails of the creep kinetics are reproduced. An additional validation is based on experimental tests in compression, traction and flexion where the main parameters of the modeling are detailed. Thus, we can conclude on the

  1. Ageing at 1203K of 20/25Nb stainless steel AGR fuel cladding material - microstructural development and its effect on creep properties

    International Nuclear Information System (INIS)

    Ecob, R.C.; Gilmour, T.C.

    1986-11-01

    The effects of ageing at 1203K for times up to 2.69Ms on the uniaxial constant stress creep properties of a 20/25Nb AGR fuel cladding alloy at 1073 and 1173K have been investigated and correlated with quantitative measurements of the microstructural developments which occur during exposure to both the ageing and creep testing temperatures. A single creep testing stress of 86.6MPa has been used. It is shown that the variation of minimum creep rate can only be explained in terms of the observed NbC particle coarsening at short ageing times (up to 7.44ks). After longer ageing treatments the minimum creep rate tends to decrease with ageing time, which is interpreted as being due to grain growth and, in particular, the onset of secondary recrystallisation. The minimum creep rates displayed by the material are reduced by factors of up to 20 in the presence of partial secondary recrystallisation. It is concluded that the effects of the development of the NbC particle distributions during 1203K ageing on the 1073 or 1173K uniaxial creep endurance of the material are relatively small. Consideration is given to the circumstances in which it might be of more importance, which include longer 1203K ageing treatments, more complex low strain stress/strain cycles. During the ageing treatments and creep tests investigated in the present work, the only significant influences on creep properties arise from grain growth and secondary recrystallisation. (UK)

  2. Ageing of fibre reinforced polymer composite selected as a bearing material for Rams of 540 MWe fuelling machine

    International Nuclear Information System (INIS)

    Limaye, P.K.; Soni, N.L.; Agrawal, R.G.

    2006-01-01

    Fibre-reinforced-polymer-composite material has been suggested as a bearing material to overcome tribological problems witnessed during the testing of Ram assembly of the 540 MWe fuelling machine at RTD. After successful trials at B-Ram the composite material has been adapted for B-RAM, C-Ram and RDB head at fuelling machines being tested at RTD, Hall 7 and at Tarapur. Laboratory evaluations were also carried out at Tribology Lab RTD to study effect of radiation on the composite. Paper deals with the various aspects of life prediction of this material in term of wear and radiation damage. (author)

  3. Identification and Assessment of Material Models for Age-Related Degradation of Structures and Passive Components in Nuclear Power Plants

    International Nuclear Information System (INIS)

    Choi, In Kil; Kim, Min Kyu; Hofmayer, Charles; Braverman, Joseph; Nie, Jinsuo

    2009-03-01

    This report describes the research effort performed by BNL for the Year 2 scope of work. This research focused on methods that could be used to represent the long-term behavior of materials used at NPPs. To achieve this BNL reviewed time-dependent models which can approximate the degradation effects of the key materials used in the construction of structures and passive components determined to be of interest in the Year 1 effort. The intent was to review the degradation models that would cover the most common time-dependent changes in material properties for concrete and steel components

  4. Dynamic J-R Characteristics of RCS Pipe Materials for Ulchin Unit 3/4. (Evaluation of Dynamic Strain Aging Effects)

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Jun Hwa; Lee, Bong Sang; Yoon, Ji Hyun; Oh, Jong Myung; Kim, Jin Won [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1997-09-01

    5 materials (45 1T-CT specimens) were tested to evaluate dynamic J-R characteristics of RCS Pipe Materials for Ulchin Unit 3/4 (Evaluation of Dynamic Strain Aging Effects). The tests were performed by DCPD method at 316 deg C and 25 deg C. The loading rates were 1000mm/min and 2000mm/min. The objectives of this project were to obtain the dynamic J-R curves data of ferritic steels for application of LBB to the RCS pipes of Ulchin Unit 3/4. The test results showed that all of the tested dynamic J-R curves of 5 materials were above the lower bound curve of static J-R curve of pipe materials for Ulchin Unit 3/4. 10 refs., 4 tabs., 16 figs. (author)

  5. The effects of thermal aging on material behavior and strength of CF8M in nuclear reactor coolant system

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Jae Do; Lee, Yong Seon; Park, Jung Cheol; In, Jae Hyeon; Woo, Seung Wan; Pae, Yong Tak; Nam, Uk Hui; Park, Yun Won [Yeungnam Univ., Gyeongsan (Korea, Republic of)

    1999-03-15

    The following investigations are performed in order to estimate the mechanism of the structural integrity, and the life prediction. The CF8M is observed a brittle behavior in the range of 475 .deg. C. The five classes of the thermally aged CF8M specimen are prepared using an artificially accelerated aging method. Namely, after the specimen are held for 100, 300, 900, 1800 and 3600 hrs. at 430 .deg. C respectively, the specimen are water cooled to room temperature. In addition to the thermally aged specimens the specimens associated with {delta}-phase degradation are prepared. After the specimens are maintained for 20 min, 5, 15, 50 and 150 hrs. at 700 .deg. C, respectively. which is in the range of {delta}-phase degradation, all specimens are cooled in water. The impact energy variations are measured for both the aged and virgin specimen at -173, -70, -32, 27 and 100 .deg. C, respectively, through the Charpy impact tests in addition to the hardness tests. The characteristics of the fatigue crack growth and low cycle fatigue tests are investigated using both aged and virgin specimens. Also fractured surfaces of the specimen are observed using the scanning electronic microscopy. J-R curve and J{sub IC} of the aged and virgin specimens are found J{sub IC} in order to predict the critical flaw size and fatigue life.

  6. Applications of bioactive material from snakehead fish (Channa striata) for repairing of learning-memory capability and motoric activity: a case study of physiological aging and aging-caused oxidative stress in rats

    Science.gov (United States)

    Sunarno, Sunarno; Muflichatun Mardiati, Siti; Rahadian, Rully

    2018-05-01

    Physiological aging and aging due to oxidative stress are a major factor cause accelerated brain aging. Aging is characterized by a decrease of brain function of the hippocampus which is linked to the decline in the capability of learning-memory and motoric activity. The objective of this research is to obtain the important information about the mechanisms of brain antiaging associated with the improvement of hippocampus function, which includes aspects of learning-memory capability and motoric activity as well as mitochondrial ultrastructure profile of hippocampus cornu ammonis cells after treated by fish snakehead fish extract. Snakehead fish in Rawa Pening Semarang District allegedly holds the potential of endemic, which contains bioactive antiaging material that can prevent aging or improve the function of the hippocampus. This research has been conducted using a completely randomized design consisting of four treatments with five replications. The treatments were including rats with physiological aging or aging due to oxidative stress which was treated and without treated with meat extract of snakehead fish. The research was divided into two stages, i.e., determining of learning-memory capability, and determining motoric activity. The measured-parameters are time response to find feed, distance travel, time stereotypes, ambulatory time, and resting time. The result showed that the snakehead fish meat extract might improve function hippocampus, both in physiological aging or aging due to oxidative stress. The capability of learning and memory showed that the rats in both conditions of aging after getting treatment of meat extract of snakehead fish could get a feed in the fourth arm maze faster than rats untreated snakehead fish meat extract. Similarly, the measurement of the distance traveled, time stereotypes, ambulatory time, and resting time showed that rats which received treatment of meat extract of snakehead fish were better than the untreated rats. To

  7. Long-term ageing tests on glazing materials for solar collectors; Langzeit-Alterungsuntersuchung an Abdeckungsmaterialien fuer thermische Sonnenkollektoren

    Energy Technology Data Exchange (ETDEWEB)

    Ruesch, F.; Brunold, S.; Haeuselmann, T.; Frank, E.; Frei, U.

    2008-02-15

    This report made by the Swiss Institute for Solar Technology at the University of Applied Sciences in Rapperswil, Switzerland, for Swiss Federal Office of Energy (SFOE) takes a look at the results of a project that investigated the long-term behaviour of glazing materials for solar collectors. The locations tested and their associated meteorological data are presented and the tests made concerning the optical characteristics of several different types of glazing are discussed. Soiling and degradation are also looked at. An overview of the solar transmission of the various materials is presented. Details on the various materials such as glass, polymethyl metacrylate (PMMA), polycarbonate (PC), fluorised plastics, unsaturated polyester (UP), polyvinyl chloride (PVC) and polyethylene terephthalate (PET) are presented.

  8. Experimental data base for assessment of irradiation induced ageing effects in pre-irradiated RPV materials of German PWR

    Energy Technology Data Exchange (ETDEWEB)

    Hein, H.; Gundermann, A.; Keim, E.; Schnabel, H. [AREVA NP GmbH (Germany); Ganswind, J. [VGB PowerTech e.V (Germany)

    2011-07-01

    The 5 year research program CARISMA which ended in 2008 has produced a data base to characterize the fracture toughness of pre-irradiated original RPV (Reactor Pressure Vessel) materials being representative for all four German PWR construction lines of former Siemens/KWU company. For this purpose tensile, Charpy-V impact, crack initiation and crack arrest tests have been performed for three base materials and four weld metals irradiated to neutron fluences beyond the designed EoL range. RPV steels with optimized chemical composition and with high copper as well as high nickel content were examined in this study. The RTNDT concept and the Master Curve approach were applied for the assessment of the generated data in order to compare both approaches. A further objective was to clarify in which extent crack arrest curves can be generated for irradiated materials and how crack arrest can be integrated into the Master Curve approach. By the ongoing follow-up project CARINA the experimental data base will be extended by additional representative materials irradiated under different conditions and with respect to the accumulated neutron fluences and specific impact parameters such as neutron flux and manufacturing effects. The irradiation data cover also the long term irradiation behavior of the RPV steels concerned. Moreover, most of the irradiated materials were and will be used for microstructural examinations to get a deeper insight in the irradiation embrittlement mechanisms and their causal relationship to the material property changes. By evaluation of the data base the applicability of the Master Curve approach for both crack initiation and arrest was confirmed to a large extent. Moreover, within both research programs progress was made in the development of crack arrest test techniques and in specific issues of RPV integrity assessment. (authors)

  9. Education, material condition and physical functioning trajectories in middle-aged and older adults in Central and Eastern Europe: a cross-country comparison

    Science.gov (United States)

    Hu, Yaoyue; Pikhart, Hynek; Pająk, Andrzej; Kubínová, Růžena; Malyutina, Sofia; Besala, Agnieszka; Peasey, Anne; Marmot, Michael; Bobak, Martin

    2016-01-01

    Background Two competing hypotheses, cumulative advantage/disadvantage and age-as-leveller, have been proposed to explain the contradictory findings on socioeconomic differences in health over the lifespan. To test these hypotheses, this investigation examined the influence of educational attainment and material condition on individual trajectories of physical functioning (PF) in unexplored ageing populations in Central and Eastern Europe. Methods 28 783 men and women aged 45–69 years selected from populations in seven Czech towns, Krakow (Poland) and Novosibirsk (Russia). PF was measured by the Physical Functioning Subscale (PF-10) of the Short-Form-36 questionnaire (SF-36) at baseline and three subsequent occasions. The highest educational attainment was self-reported at baseline, and material condition was captured by the sum score of 12 household amenities and assets. Results In all cohorts, participants with a university degree had the highest PF-10 score at baseline and slowest rate of decline in the score during follow-up, while the lowest baseline scores and fastest decline rate were found in participants with less than secondary education in all cohorts and in Russians with secondary education. Similar disparities in the baseline PF-10 score and decline rate were observed across tertiles of material condition, but differences in decline rates across the three tertiles among Czechs or between the lower two tertiles among Russians were not statistically significant. Conclusions Disparities in PF by educational attainment and material condition among middle-aged and older adults in Central and Eastern Europe existed at baseline and widened during ∼10 years of follow-up, supporting the cumulative advantage/disadvantage hypothesis. PMID:27194710

  10. Soiling of building envelope surfaces and its effect on solar reflectance – Part II: Development of an accelerated aging method for roofing materials

    Energy Technology Data Exchange (ETDEWEB)

    Sleiman, Mohamad [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kirchstetter, Thomas W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Berdahl, Paul [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gilbert, Haley E. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Quelen, Sarah [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Marlot, Lea [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Preble, Chelsea V. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Chen, Sharon [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Montalbano, Amandine [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Rosseler, Olivier [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Akbari, Hashem [Concordia Univ., Montreal (Canada); Levinson, Ronnen [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Destaillats, Hugo [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-01-09

    Highly reflective roofs can decrease the energy required for building air conditioning, help mitigate the urban heat island effect, and slow global warming. However, these benefits are diminished by soiling and weathering processes that reduce the solar reflectance of most roofing materials. Soiling results from the deposition of atmospheric particulate matter and the growth of microorganisms, each of which absorb sunlight. Weathering of materials occurs with exposure to water, sunlight, and high temperatures. This study developed an accelerated aging method that incorporates features of soiling and weathering. The method sprays a calibrated aqueous soiling mixture of dust minerals, black carbon, humic acid, and salts onto preconditioned coupons of roofing materials, then subjects the soiled coupons to cycles of ultraviolet radiation, heat and water in a commercial weatherometer. Three soiling mixtures were optimized to reproduce the site-specific solar spectral reflectance features of roofing products exposed for 3 years in a hot and humid climate (Miami, Florida); a hot and dry climate (Phoenix, Arizona); and a polluted atmosphere in a temperate climate (Cleveland, Ohio). A fourth mixture was designed to reproduce the three-site average values of solar reflectance and thermal emittance attained after 3 years of natural exposure, which the Cool Roof Rating Council (CRRC) uses to rate roofing products sold in the US. This accelerated aging method was applied to 25 products₋single ply membranes, factory and field applied coatings, tiles, modified bitumen cap sheets, and asphalt shingles₋and reproduced in 3 days the CRRC's 3-year aged values of solar reflectance. In conclusion, this accelerated aging method can be used to speed the evaluation and rating of new cool roofing materials.

  11. Education, material condition and physical functioning trajectories in middle-aged and older adults in Central and Eastern Europe: a cross-country comparison.

    Science.gov (United States)

    Hu, Yaoyue; Pikhart, Hynek; Pająk, Andrzej; Kubínová, Růžena; Malyutina, Sofia; Besala, Agnieszka; Peasey, Anne; Marmot, Michael; Bobak, Martin

    2016-11-01

    Two competing hypotheses, cumulative advantage/disadvantage and age-as-leveller, have been proposed to explain the contradictory findings on socioeconomic differences in health over the lifespan. To test these hypotheses, this investigation examined the influence of educational attainment and material condition on individual trajectories of physical functioning (PF) in unexplored ageing populations in Central and Eastern Europe. 28 783 men and women aged 45-69 years selected from populations in seven Czech towns, Krakow (Poland) and Novosibirsk (Russia). PF was measured by the Physical Functioning Subscale (PF-10) of the Short-Form-36 questionnaire (SF-36) at baseline and three subsequent occasions. The highest educational attainment was self-reported at baseline, and material condition was captured by the sum score of 12 household amenities and assets. In all cohorts, participants with a university degree had the highest PF-10 score at baseline and slowest rate of decline in the score during follow-up, while the lowest baseline scores and fastest decline rate were found in participants with less than secondary education in all cohorts and in Russians with secondary education. Similar disparities in the baseline PF-10 score and decline rate were observed across tertiles of material condition, but differences in decline rates across the three tertiles among Czechs or between the lower two tertiles among Russians were not statistically significant. Disparities in PF by educational attainment and material condition among middle-aged and older adults in Central and Eastern Europe existed at baseline and widened during ∼10 years of follow-up, supporting the cumulative advantage/disadvantage hypothesis. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  12. The Use of Print Materials in the Internet Age: A Comparative Study of Academic Library Circulation Patterns

    Science.gov (United States)

    Haley, Daniel Joseph

    2010-01-01

    The circulation records from 1997/98 to 2007/08 for UCLA and from 2000/01 to 2007/08 for Pasadena City College (PCC) were analyzed to examine patterns in the use of print materials during a period of increasingly available online digital information resources. The analysis included examinations of longitudinal circulation patterns broken down by…

  13. How things matter in everyday lives of preschool age children: material-semiotic investigations in psychology and education

    NARCIS (Netherlands)

    Kontopodis, M.

    2012-01-01

    This article draws on materials from ethnographic and participatory research on everyday eating practices in Berlin kindergartens. It argues that agency is not always a-priori located in the human subject. Agency can be translated and distributed over relational networks that include people and

  14. IMPROVED AGING PERFORMANCE OF VIRGIN EPDM ROOF-SHEETING COMPOUNDS WITH AMINE-DEVULCANIZED EPDM WEATHERSTRIP MATERIAL

    NARCIS (Netherlands)

    Dijkhuis, K. A. J.; Dierkes, W. K.; Noordermeer, J. W. M.; Sutanto, P.

    2008-01-01

    Sulfur-cured EPDM building-profile material was reclaimed in a co-rotating twin-screw extruder using hexadecylamine as reclaiming aid. This reclaim was blended with increasing amounts of a virgin EPDM roof-sheeting masterbatch and cured at temperatures allowing for a reversion-free vulcanization.

  15. Thermal aging of electrolytes used in lithium-ion batteries - An investigation of the impact of protic impurities and different housing materials

    Science.gov (United States)

    Handel, Patricia; Fauler, Gisela; Kapper, Katja; Schmuck, Martin; Stangl, Christoph; Fischer, Roland; Uhlig, Frank; Koller, Stefan

    2014-12-01

    Thermal degradation products in lithium-ion batteries result mainly from hydrolysis sensitivity of lithium hexafluorophosphate (LiPF6). As organic carbonate solvents contain traces of protic impurities, the thermal decomposition of electrolytes is enhanced. Therefore, resulting degradation products are studied with nuclear magnetic resonance spectroscopy (NMR) and gas chromatography mass spectrometry (GC-MS). The electrolyte contains 1 M LiPF6 in a binary mixture of ethylene carbonate (EC) and diethylene carbonate (DEC) in a ratio of 1:2 (v/v) and is aged at ambient and elevated temperature. The impact of protic impurities, either added as deionized water or incorporated in positive electrode material, upon aging is investigated. Further, the influence of different housing materials on the electrolyte degradation is shown. Difluorophosphoric acid is identified as main decomposition product by NMR-spectroscopy. Traces of other decomposition products are determined by headspace GC-MS. Acid-base and coulometric titration are used to determine the total amount of acid and water content upon aging, respectively. The aim of this investigation is to achieve profound understanding about the thermal decomposition of one most common used electrolyte in a battery-like housing material.

  16. Soil microbial biomass under pine forests in the north-western Spain: influence of stand age, site index and parent material

    Energy Technology Data Exchange (ETDEWEB)

    Mahia, J.; Perez-Ventura, L.; Cabaneiro, A.; Diaz-Ravina, M.

    2006-07-01

    The effects of stand age, site index and parent material on soil biochemical properties related to biomass (extractable C, microbial C and metabolic quotient) were examined in the 0-15 cm mineral soil layers of Pinus pinaster and Pinus sylvestris stand from NW Spain. Two productivity levels (low and high site index), two ages (young and old) and two parent soil materials (granite and acid schists) were considered. The data indicated that there were differences in microbial parameters in soils under different species. In general in P. pinaster forest higher values of biochemical parameters expressed on organic C basis, were observed in the stands of high site index as compared with the low ones; in contrast, in P. sylvestris no differences among stand site index were detected. In both species different results were also observed depending on parent material and a significant effect of stand age was detected for extractable C and microbial C in P. pinaster forest developed over granite. The data seem to indicate that measured parameters may have the potential to be used as indicators of the effect of forest management on soil organic matter quality. (Author) 25 refs.

  17. Learning to Teach in the Digital Age: New Materialities and Maker Paradigms in Schools. New Literacies and Digital Epistemologies

    Science.gov (United States)

    Justice, Sean

    2016-01-01

    "Learning to Teach in the Digital Age" tells the story of a group of K-12 teachers as they began to connect with digital making and learning pedagogies. Guiding questions at the heart of this qualitative case study asked how teaching practices engaged with and responded to the maker movement and digital making and learning tools and…

  18. Modeling the mechanical and aging properties of silicone rubber and foam - stockpile-historical & additively manufactured materials

    Energy Technology Data Exchange (ETDEWEB)

    Maiti, A; Weisgraber, T H; Gee, R H

    2014-09-30

    M97* and M9763 belong to the M97xx series of cellular silicone materials that have been deployed as stress cushions in some of the LLNL systems. Their purpose of these support foams is to distribute the stress between adjacent components, maintain relative positioning of various components, and mitigate the effects of component size variation due to manufacturing and temperature changes. In service these materials are subjected to a continuous compressive strain over long periods of time. In order to ensure their effectiveness, it is important to understand how their mechanical properties change over time. The properties we are primarily concerned about are: compression set, load retention, and stress-strain response (modulus).

  19. A Preliminary Numerical Investigation on the Influence of Material Variability in the Early-Age Cracking Behavior of Restrained Concrete

    DEFF Research Database (Denmark)

    Radlinska, Aleksandra; Pease, Bradley Justin; Weiss, Jason

    2007-01-01

    The restraint of drying, autogenous, or thermal shrinkage can result in the development of tensile residual stresses. If the residual stresses that develop are large enough, they may cause cracking in the concrete. Substantial research has focused on the development of test methods to assess stress...... development and the corresponding potential for cracking. These test methods frequently focus on the determination of material properties that can be used in deterministic computer programs to simulate stress development and cracking. While these models are a great step forward, variability is inherent...... in the material properties, the construction processes, and the environmental conditions (i.e., temperature and relative humidity). This paper presents results of considering variability in a model for predicting the time of shrinkage cracking. A Monte Carlo simulation procedure has been adopted to account...

  20. Guide for Operational Configuration Management Program including the adjunct programs of design reconstitution and material condition and aging management

    International Nuclear Information System (INIS)

    1993-11-01

    This standard presents program criteria and implementation guidance for an operational configuration management program for DOE nuclear and non-nuclear facilities in the operational phase. Portions of this standard are also useful for other DOE processes, activities, and programs. This Part 1 contains foreword, glossary, acronyms, bibliography, and Chapter 1 on operational configuration management program principles. Appendices are included on configuration management program interfaces, and background material and concepts for operational configuration management

  1. IAEA Coordinated Research Project on the Establishment of a Material Properties Database for Irradiated Core Structural Components for Continued Safe Operation and Lifetime Extension of Ageing Research Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Borio Di Tigliole, A.; Schaaf, Van Der; Barnea, Y.; Bradley, E.; Morris, C.; Rao, D. V. H. [Research Reactor Section, Vianna (Australia); Shokr, A. [Research Reactor Safety Section, Vienna (Australia); Zeman, A. [International Atomic Energy Agency, Vienna (Australia)

    2013-07-01

    Today more than 50% of operating Research Reactors (RRs) are over 45 years old. Thus, ageing management is one of the most important issues to face in order to ensure availability (including life extension), reliability and safe operation of these facilities for the future. Management of the ageing process requires, amongst others, the predictions for the behavior of structural materials of primary components subjected to irradiation such as reactor vessel and core support structures, many of which are extremely difficult or impossible to replace. In fact, age-related material degradation mechanisms resulted in high profile, unplanned and lengthy shutdowns and unique regulatory processes of relicensing the facilities in recent years. These could likely have been prevented by utilizing available data for the implementation of appropriate maintenance and surveillance programmes. This IAEA Coordinated Research Project (CRP) will provide an international forum to establish a material properties Database for irradiated core structural materials and components. It is expected that this Database will be used by research reactor operators and regulators to help predict ageing related degradation. This would be useful to minimize unpredicted outages due to ageing processes of primary components and to mitigate lengthy and costly shutdowns. The Database will be a compilation of data from RRs operators' inputs, comprehensive literature reviews and experimental data from RRs. Moreover, the CRP will specify further activities needed to be addressed in order to bridge the gaps in the new created Database, for potential follow-on activities. As per today, 13 Member States (MS) confirmed their agreement to contribute to the development of the Database, covering a wide number of materials and properties. The present publication incorporates two parts: the first part includes details on the pre-CRP Questionnaire, including the conclusions drawn from the answers received from

  2. IAEA Coordinated Research Project on the Establishment of a Material Properties Database for Irradiated Core Structural Components for Continued Safe Operation and Lifetime Extension of Ageing Research Reactors

    International Nuclear Information System (INIS)

    Borio Di Tigliole, A.; Schaaf, Van Der; Barnea, Y.; Bradley, E.; Morris, C.; Rao, D. V. H.; Shokr, A.; Zeman, A.

    2013-01-01

    Today more than 50% of operating Research Reactors (RRs) are over 45 years old. Thus, ageing management is one of the most important issues to face in order to ensure availability (including life extension), reliability and safe operation of these facilities for the future. Management of the ageing process requires, amongst others, the predictions for the behavior of structural materials of primary components subjected to irradiation such as reactor vessel and core support structures, many of which are extremely difficult or impossible to replace. In fact, age-related material degradation mechanisms resulted in high profile, unplanned and lengthy shutdowns and unique regulatory processes of relicensing the facilities in recent years. These could likely have been prevented by utilizing available data for the implementation of appropriate maintenance and surveillance programmes. This IAEA Coordinated Research Project (CRP) will provide an international forum to establish a material properties Database for irradiated core structural materials and components. It is expected that this Database will be used by research reactor operators and regulators to help predict ageing related degradation. This would be useful to minimize unpredicted outages due to ageing processes of primary components and to mitigate lengthy and costly shutdowns. The Database will be a compilation of data from RRs operators' inputs, comprehensive literature reviews and experimental data from RRs. Moreover, the CRP will specify further activities needed to be addressed in order to bridge the gaps in the new created Database, for potential follow-on activities. As per today, 13 Member States (MS) confirmed their agreement to contribute to the development of the Database, covering a wide number of materials and properties. The present publication incorporates two parts: the first part includes details on the pre-CRP Questionnaire, including the conclusions drawn from the answers received from the MS

  3. Experience in monitoring ageing phenomena for improving nuclear power plant availability. Proceedings of a specialists' meeting. Working material

    International Nuclear Information System (INIS)

    1992-01-01

    For more than thirty years nuclear power plants have been supplying electricity to national grids. Today, the nuclear power community is facing great challenges. The safe, reliable operation of existing nuclear power plants (NPPs) must continue to be ensured. From an economic viewpoint, because of the long lead times associated with bringing new plants into service, securing the continued operation of existing plants for their planned lifetimes and possible life extension will be very important in the near term for meeting electrical power demands. The IAEA programmes in nuclear power plant ageing and life extension and in control and instrumentation promote technical information exchange between Member States with new programmes, offers assistance to Member States with an interest in reliability of NPP components, in-service inspection methods and programmes using on-line techniques, component monitoring and special technological topics of nuclear reactors. Significant experience already exists in the nuclear industry in developing and applying the monitoring techniques for different nuclear power plant applications, especially in monitoring of ageing phenomena for improving NPP availability. The purpose of this Specialists' Meeting was to bring together experts from operations, design, research and development and licensing to share their experience in: ageing mechanics of key structural components, methods of monitoring such ageing, tools for cost-effective implementation of the methods and methodologies, life management approaches and examples from current reactors, future direction for monitoring of key structural components in nuclear power plants. The meeting was organized by the IAEA International Working Groups on Life Management of Nuclear Power Plants (IWG-LMNPP) and Nuclear Power Plant Control and Instrumentation (TWG-NPPCI) in co-operation with the Czechoslovak Atomic Energy Commission and Skoda concern. Around 40 participants from 10 countries

  4. Experience in monitoring ageing phenomena for improving nuclear power plant availability. Proceedings of a specialists' meeting. Working material

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1992-07-01

    For more than thirty years nuclear power plants have been supplying electricity to national grids. Today, the nuclear power community is facing great challenges. The safe, reliable operation of existing nuclear power plants (NPPs) must continue to be ensured. From an economic viewpoint, because of the long lead times associated with bringing new plants into service, securing the continued operation of existing plants for their planned lifetimes and possible life extension will be very important in the near term for meeting electrical power demands. The IAEA programmes in nuclear power plant ageing and life extension and in control and instrumentation promote technical information exchange between Member States with new programmes, offers assistance to Member States with an interest in reliability of NPP components, in-service inspection methods and programmes using on-line techniques, component monitoring and special technological topics of nuclear reactors. Significant experience already exists in the nuclear industry in developing and applying the monitoring techniques for different nuclear power plant applications, especially in monitoring of ageing phenomena for improving NPP availability. The purpose of this Specialists' Meeting was to bring together experts from operations, design, research and development and licensing to share their experience in: ageing mechanics of key structural components, methods of monitoring such ageing, tools for cost-effective implementation of the methods and methodologies, life management approaches and examples from current reactors, future direction for monitoring of key structural components in nuclear power plants. The meeting was organized by the IAEA International Working Groups on Life Management of Nuclear Power Plants (IWG-LMNPP) and Nuclear Power Plant Control and Instrumentation (TWG-NPPCI) in co-operation with the Czechoslovak Atomic Energy Commission and Skoda concern. Around 40 participants from 10 countries.

  5. On the Relation of Setting and Early-Age Strength Development to Porosity and Hydration in Cement-Based Materials

    OpenAIRE

    Lootens, Didier; Bentz, Dale P.

    2016-01-01

    Previous research has demonstrated a linear relationship between compressive strength (mortar cubes and concrete cylinders) and cumulative heat release normalized per unit volume of (mixing) water for a wide variety of cement-based mixtures at ages of 1 d and beyond. This paper utilizes concurrent ultrasonic reflection and calorimetry measurements to further explore this relationship from the time of specimen casting to 3 d. The ultrasonic measurements permit a continuous evaluation of thicke...

  6. Effect of aging on the bioavailability and fractionation of arsenic in soils derived from five parent materials in a red soil region of Southern China

    International Nuclear Information System (INIS)

    Wang, Yanan; Zeng, Xibai; Lu, Yahai; Su, Shiming; Bai, Lingyu; Li, Lianfang; Wu, Cuixia

    2015-01-01

    The effects of aging time and soil parent materials on the bioavailability and fractionations of arsenic (As) in five red soils were studied. The results indicated that As bioavailability in all soils decreased during aging, especially with a sharp decline occurring in the first 30 days. After aging for 360 days, the highest available As concentration, which accounted for 12.3% of the total, was observed in soils derived from purple sandy shale. While 2.67% was the lowest proportion of the available As in soils derived from quaternary red clay. Furthermore, the best fit of the available As changing with aging time was obtained using the pseudo-second-order model (R"2 = 0.939–0.998, P < 0.05). Notably, Al oxides played a more crucial role (R"2 = 0.89, P<0.05) than did Fe oxides in controlling the rate of As aging. The non-specially and specially absorbed As constituted the primary forms of available As. - Highlights: • The soil derived from purple sandy shale had a relatively higher risk of As toxicity for agricultural production. • The best fit of the variations of available As during the aging time was obtained using the pseudo-second-order model. • Al oxides played a more crucial role than did Fe oxides in controlling the rate of As aging. - Al oxides played a more crucial role than did Fe oxides in controlling the rate of As aging in these red soils.

  7. [Evaluation of the dental pathology in archaeological skeletal material: prevalence of dental caries since prehistory to modern age].

    Science.gov (United States)

    Stránská, Petra

    2013-01-01

    The evaluation of the dental health of past populations is an important part of the anthropological analysis of human skeletal remains uncovered during the archaeological excavations. The results provide the important information not only of the overall health of past populations, but also are reflective of the nutrition or the social status of our ancestors. We focused on the comparison of dental caries from prehistoric times to the present day. The aim was to evaluate the dental decay in several prehistoric, Early Medieval and modern populations and determine whether and to what extent the decay differ between the individual groups. METHODS AND RESULTS. We observed the permanent dentition in adult men and females, who were divided into three groups: the population of the younger Eneolithic to the Bronze Age, the population of the Early Middle Ages and the population of the modern times. We used the Index of Intensity of Caries I-CE and the Index of Caries Frequency F-CE to evaluate the incidence of caries and intra-vital losses. The comparison was carried out between groups, between both of jaws and between individual teeth. We took into account sex and age of the individuals studied. The highest value of F-CE was set in the population of the modern times (67.5). The difference in caries frequency among populations was not significant. The intensity of caries was the highest in modern population (I-CE: 13.2). Compared with the two older populations the difference was statistically highly significant (p 0.001).With regard to sex, the results differed between populations. It could be caused by a different frequency of men and females in individual groups.The correlation of intensity of caries with age was confirmed. Some partial results were affected by unequal frequency of age categories. CONCLUSION. The results showed the worst dental health in the population of the modern times. The null hypothesis,that tooth decay among the individual populations from different

  8. Review of the status of nondestructive measurement techniques to quantify material property degradation due to aging and planning for further evaluation

    International Nuclear Information System (INIS)

    Boyd, D.M.; Bruemmer, S.M.; Green, E.R.; Schuster, G.J.; Simonen, E.P.

    1989-01-01

    The materials used in nuclear reactors are inspected periodically during the service life of the power plant to detect degradation that might occur. These inspections follow the rules specified in Section XI of the ASME Boiler and Pressure Vessel Code. These inspections are designed to detect service-induced failure mechanisms. This program is designed not to look at the detection of defects but the marking of nondestructive measurements to quantify the material properties that a defect may reside in or the incipient condition(s) that may initiate a defect. This program is intended to provide an assessment of the technologies that are available to quantify with nondestructive measurements material properties or material property changes related to degradation due to aging of structural components in light water reactors. In addition, a program plan will be developed that describes the work necessary to create adequate engineering data bases for demonstrating and validating prototypic systems for making these measurements. The main thrust this year has been an extensive review of literature and an assessment of the technology. The second major activity was the planning of a workshop to bring together 30 leading experts in materials and NDE to discuss the state-of-the-art and to address where future work should go

  9. Review of the status of nondestructive measurement techniques to quantify material property degradation due to aging and planning for further evaluation

    International Nuclear Information System (INIS)

    Doctor, S.R.; Boyd, D.M.; Bruemmer, S.M.; Green, E.R.; Schuster, G.J.; Simonen, E.P.

    1989-01-01

    The materials used in nuclear reactors are inspected periodically during the service life of the power plant to detect degradation that might occur. These inspections follow the rules specified in Section XI of the ASME Boiler and Pressure Vessel Code. These inspections are designed to detect service-induced failure mechanisms. This program is designed not to look at the detection of defects but the making of nondestructive measurements to quantify the material properties that a defect may reside in or the incipient condition(s) that may initiate a defect. This program is intended to provide an assessment of the technologies that are available to quantify with nondestructive measurements material properties or material property changes related to degradation due to aging of structural components in light water reactors. In addition, a program plan will be developed that describes the work necessary to create adequate engineering data bases for demonstrating and validating prototypic systems for making these measurements. The main thrust this year has been an extensive review of literature and an assessment of the technology. The second major activity was the planning of a workshop to bring together 30 leading experts in materials and nondestructive evaluation to discuss the state-of-the-art and to address where future work should go

  10. Forensic engineering of advanced polymeric materials Part IV: Case study of oxo-biodegradable polyethylene commercial bag - Aging in biotic and abiotic environment.

    Science.gov (United States)

    Musioł, Marta; Rydz, Joanna; Janeczek, Henryk; Radecka, Iza; Jiang, Guozhan; Kowalczuk, Marek

    2017-06-01

    The public awareness of the quality of environment stimulates the endeavor to safe polymeric materials and their degradation products. The aim of the forensic engineering case study presented in this paper is to evaluate the aging process of commercial oxo-degradable polyethylene bag under real industrial composting conditions and in distilled water at 70°C, for comparison. Partial degradation of the investigated material was monitored by changes in molecular weight, thermal properties and Keto Carbonyl Bond Index and Vinyl Bond Index, which were calculated from the FTIR spectra. The results indicate that such an oxo-degradable product offered in markets degrades slowly under industrial composting conditions. Even fragmentation is slow, and it is dubious that biological mineralization of this material would occur within a year under industrial composting conditions. The slow degradation and fragmentation is most likely due to partially crosslinking after long time of degradation, which results in the limitation of low molecular weight residues for assimilation. The work suggests that these materials should not be labeled as biodegradable, and should be further analyzed in order to avoid the spread of persistent artificial materials in nature. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Influence of core thickness and artificial aging on the biaxial flexural strength of different all-ceramic materials: An in-vitro study.

    Science.gov (United States)

    Dikicier, Sibel; Ayyildiz, Simel; Ozen, Julide; Sipahi, Cumhur

    2017-05-31

    The purpose of this study was to investigate the flexural strength of all-ceramics with varying core thicknesses submitted to aging. In-Ceram Alumina (IC), IPS e.max Press (EM) and Katana (K) (n=40), were selected. Each group contained two core groups based on the core thickness as follows: IC/0.5, IC/0.8, EM/0.5, EM/0.8, K/0.5 and K/0.8 mm in thickness (n=20 each). Ten specimens from each group were subjected to aging and all specimens were tested for strength in a testing machine either with or without being subjected aging. The mean strength of the K were higher (873.05 MPa) than that of the IC (548.28 MPa) and EM (374.32 MPa) regardless of core thickness. Strength values increased with increasing core thickness for all IC, EM and K regardless of aging. Results of this study concluded that strength was not significantly affected by aging. Different core thicknesses affected strength of the all-ceramic materials tested (p<0.05).

  12. Comparative Investigation on the Performance of Modified System Poles and Traditional System Poles Obtained from PDC Data for Diagnosing the Ageing Condition of Transformer Polymer Insulation Materials

    Directory of Open Access Journals (Sweden)

    Jiefeng Liu

    2018-02-01

    Full Text Available The life expectancy of a transformer is largely depended on the service life of transformer polymer insulation materials. Nowadays, several papers have reported that the traditional system poles obtained from polarization and depolarization current (PDC data can be used to assess the condition of transformer insulation systems. However, the traditional system poles technique only provides limited ageing information for transformer polymer insulation. In this paper, the modified system poles obtained from PDC data are proposed to assess the ageing condition of transformer polymer insulation. The aim of the work is to focus on reporting a comparative investigation on the performance of modified system poles and traditional system poles for assessing the ageing condition of a transformer polymer insulation system. In the present work, a series of experiments have been performed under controlled laboratory conditions. The PDC measurement data, degree of polymerization (DP and moisture content of the oil-immersed polymer pressboard specimens were carefully monitored. It is observed that, compared to the relationships between traditional system poles and DP values, there are better correlations between the modified system poles and DP values, because the modified system poles can obtain much more ageing information on transformer polymer insulation. Therefore, the modified system poles proposed in the paper are more suitable for the diagnosis of the ageing condition of transformer polymer insulation.

  13. Advanced Non-Destructive Assessment Technology to Determine the Aging of Silicon Containing Materials for Generation IV Nuclear Reactors

    Science.gov (United States)

    Koenig, T. W.; Olson, D. L.; Mishra, B.; King, J. C.; Fletcher, J.; Gerstenberger, L.; Lawrence, S.; Martin, A.; Mejia, C.; Meyer, M. K.; Kennedy, R.; Hu, L.; Kohse, G.; Terry, J.

    2011-06-01

    To create an in-situ, real-time method of monitoring neutron damage within a nuclear reactor core, irradiated silicon carbide samples are examined to correlate measurable variations in the material properties with neutron fluence levels experienced by the silicon carbide (SiC) during the irradiation process. The reaction by which phosphorus doping via thermal neutrons occurs in the silicon carbide samples is known to increase electron carrier density. A number of techniques are used to probe the properties of the SiC, including ultrasonic and Hall coefficient measurements, as well as high frequency impedance analysis. Gamma spectroscopy is also used to examine residual radioactivity resulting from irradiation activation of elements in the samples. Hall coefficient measurements produce the expected trend of increasing carrier concentration with higher fluence levels, while high frequency impedance analysis shows an increase in sample impedance with increasing fluence.

  14. Presentation of Andronovsky Costume in Museum Exposition (on materials from Lisakovsk burial mound of the Bronze Age

    Directory of Open Access Journals (Sweden)

    Usmanova Emma R.

    2017-09-01

    Full Text Available The article features an analysis of ancient weaving technologies and women's costume of the Andronovo culture dating back to the Bronze Age. It features a reconstruction of this costume executed by the author on the basis of the discovered remains of woven textile and headwear decoration discovered in burial grounds of Lisakovsk area in the first half of 2nd Millennium B.C. (Kazakhstan, Kostanay Region, Kisakovsk. The preservation of textile base allowed the author to experimentally produce copies of two women's headwear pieces and a vest. As a result, two types of braid adornments were discovrered among grave artifacts. The author substantiates several ideas related to the meaning of the signs and symbols on costume details. As a result of research, the author presents the semantics of headwear corresponding to Andronovo culture in the context of the symbolism of costumes belonging to the traditional peoples of Middle Eurasia.

  15. Construction of computational program of aging in insulating materials for searching reversed sequential test conditions to give damage equivalent to simultaneous exposure of heat and radiation

    International Nuclear Information System (INIS)

    Fuse, Norikazu; Homma, Hiroya; Okamoto, Tatsuki

    2013-01-01

    Two consecutive numerical calculations on degradation of polymeric insulations under thermal and radiation environment are carried out to simulate so-called reversal sequential acceleration test. The aim of the calculation is to search testing conditions which provide material damage equivalent to the case of simultaneous exposure of heat and radiation. At least following four parameters are needed to be considered in the sequential method; dose rate and exposure time in radiation, as well as temperature and aging time in heating. The present paper discusses the handling of these parameters and shows some trial calculation results. (author)

  16. Raw material variability as archaeological tools: Preliminary results from a geochemical study of the basalt vessel workshop at Iron Age Tel Hazor, Israel

    Directory of Open Access Journals (Sweden)

    Tatjana Gluhak

    2016-10-01

    Full Text Available The discovery of a basalt vessel workshop at Tel Hazor, one of the most important Iron Age sites in the Near East, marks a turning point in our understanding of stone artifact production and distribution during the1st millennium BCE. It offers a rare opportunity to characterize ancient raw material sources, production sites, and study production, trade and distribution systems. The basalt vessel workshop, the only one of its kind in the Levant, produced large quantities of bowl preforms and production waste. To better understand the production and distribution systems behind this specialized production center, in 2011 we initiated a focused geochemical project that concentrated on the products of this unique workshop.  We measured the major and trace element composition of 44 unfinished basalt vessels from the workshop and other contexts at Hazor, and can demonstrate that the majority of these objects were derived from one specific, geochemically well-constrained, basaltic rock source. Only a few bowls clearly deviate from this geochemical composition and were produced using raw material from other sources. Thus, we believe that one major quarry existed that supplied the Hazor workshop with the majority of the basaltic raw material. The products from this specific extraction site provide us with a “Hazor reference group” that can be used to test whether or not finished vessels from Hazor and contemporary sites were produced in the Hazor workshop.

  17. ALPHA SPECTROMETRIC EVALUATION OF SRM-995 AS A POTENTIAL URANIUM/THORIUM DOUBLE TRACER SYSTEM FOR AGE-DATING URANIUM MATERIALS

    Energy Technology Data Exchange (ETDEWEB)

    Beals, D.

    2011-12-06

    Uranium-233 (t{sub 1/2} {approx} 1.59E5 years) is an artificial, fissile isotope of uranium that has significant importance in nuclear forensics. The isotope provides a unique signature in determining the origin and provenance of uranium-bearing materials and is valuable as a mass spectrometric tracer. Alpha spectrometry was employed in the critical evaluation of a {sup 233}U standard reference material (SRM-995) as a dual tracer system based on the in-growth of {sup 229}Th (t{sub 1/2} {approx} 7.34E3 years) for {approx}35 years following radiochemical purification. Preliminary investigations focused on the isotopic analysis of standards and unmodified fractions of SRM-995; all samples were separated and purified using a multi-column anion-exchange scheme. The {sup 229}Th/{sup 233}U atom ratio for SRM-995 was found to be 1.598E-4 ({+-} 4.50%) using recovery-corrected radiochemical methods. Using the Bateman equations and relevant half-lives, this ratio reflects a material that was purified {approx} 36.8 years prior to this analysis. The calculated age is discussed in contrast with both the date of certification and the recorded date of last purification.

  18. Regulatory challenges in the management of aging of structural materials in nuclear power plants; Retos reguladores en la gestion del envejecimiento de los materiales estructurales de centrales nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Castelo, C.; Mendoza, C.; Mas, E.; Conde, J. M.

    2013-07-01

    The article discusses two major pathways by which a regulatory body, and in particular the CSN, may participate in the acquisition of the necessary knowledge on mechanisms of aging of nuclear structural materials: to participate in forums to share operational experience and R and R project, both nationally and internationally. It notes the importance of this participation to carry out its regulatory function based on the knowledge acquired and the unique challenge of transferring that knowledge to rules and guidelines for their application. The article discusses various R and D projects in which the CSN participates directly. It calls for the presence of regulatory bodies in R and D project funded by the EU and the transfer of the results of such projects to codes, standards or guidelines for feasible implementation. (Author)

  19. Spatial distribution of metals in soils in Baltimore, Maryland: Role of native parent material, proximity to major roads, housing age and screening guidelines

    International Nuclear Information System (INIS)

    Yesilonis, I.D.; Pouyat, R.V.; Neerchal, N.K.

    2008-01-01

    We investigated the spatial distribution of heavy metal above-background (anthropic) contents of Cd, Co, Cu, Cr, Fe, Mn, Ni, Pb, Ti, V, and Zn in Baltimore City surface soils and related these levels to potential contaminating sources. Composite soil samples (0-10 cm depth) were digested using a nitric and hydrochloric extraction technique. Slightly more than 10% of plots exceeded United States Environmental Protection Agency screening guidelines for Pb. In a principal component analysis, the first component corresponded to Co, Cr, and Fe, which are constituents of local mafic rocks. The second component corresponded to Cu, Pb, and Zn which were significantly higher within than beyond a 100 m buffer of the major roads within the city; furthermore, Pb and Zn were higher in older residential lots. - Spatial distribution of metals in soils of an older US city (Baltimore) was affected by parent material, proximity to major roads, and housing age

  20. Quantification of climate and vegetation from southern African Middle Stone Age sites - an application using Late Pleistocene plant material from Sibudu, South Africa

    Science.gov (United States)

    Bruch, Angela A.; Sievers, Christine; Wadley, Lyn

    2012-06-01

    In southern Africa numerous Middle Stone Age (MSA) sites document important steps in technological and behavioural development leading to significant changes in the lifeways of modern humans. To assess whether these cultural changes and developments may be related to environmental changes we need to ascertain past environments. To do this we apply a new quantitative method, the GIS-based Coexistence Approach (CAGIS), on fossil plant material from the MSA site Sibudu, KwaZulu-Natal, South Africa. Previous qualitative environmental interpretations of the fossil fauna and flora of the site remain ambiguous. Because much of the material is anthropogenically introduced, it is difficult to distinguish between the effects of natural changes in the local vegetation and behavioural changes of the people that inhabited the shelter. CAGIS can be applied to such biased assemblages and seems to be an adequate method to directly quantify palaeoclimate and vegetation parameters at an archaeological site. The CAGIS analysis shows that during the Howiesons Poort (HP) Industry winters were slightly colder and drier than present, whereas during summer, temperatures and precipitation were similar to today. Post-HP winters were drier and colder than present, presumably colder than during the HP. Summer temperatures remained the same, but summer precipitation decreased from the HP to post-HP. Vegetation cover was less than today, may be even less than during the HP. The late MSA was observably warmer than the older periods, especially during winter. At the same time summer precipitation slightly increased and vegetation became more dense, but still remained generally open similar to today's anthropogenic landscape. Generally, climatic changes are most pronouncedly reflected in winter temperature parameters, especially in minimum winter temperatures, and to a lesser extent by changes in summer precipitation. The observed ecological trends seem to be affected mainly by variations through

  1. Safety Analysis of 'Older/Aged' Handling and Transportation Equipment for Heavy Loads, Radioactive Waste and Materials in Accordance with German Nuclear Standards KTA 3902, 3903 and 3905

    International Nuclear Information System (INIS)

    Macias, P.; Prucker, E.; Stang, W.

    2006-01-01

    The purpose of this paper is to present a general safety analysis of important handling and transportation processes and their related equipment ('load chains' consisting of cranes, load-bearing equipment and load-attaching points). This project was arranged by the responsible Bavarian ministry for environment, health and consumer protection (StMUGV) in agreement with the power plant operators of all Bavarian nuclear power plants to work out potential safety improvements. The range of the equipment (e.g. reactor building, crane, refuelling machine, load-bearing equipment and load-attaching points) covers the handling and transportation of fuel elements (e. g. with fuel flasks), heavy loads (e.g. reactor pressure vessel closure head, shielding slabs) and radioactive materials and waste (e.g. waste flasks, control elements, fuel channels, structure elements). The handling equipment was subjected to a general safety analysis taking into account the ageing of the equipment and the progress of standards. Compliance with the current valid requirements of the state of science and technology as required by German Atomic Act and particularly of the nuclear safety KTA-standards (3902, 3903 and 3905) was examined. The higher protection aims 'safe handling and transportation of heavy loads and safe handling of radioactive materials and waste' of the whole analysis are to avoid a criticality accident, the release of radioactivity and inadmissible effects on important technical equipment and buildings. The scope of the analysis was to check whether these protection aims were fulfilled for all important technical handling and transportation processes. In particularly the design and manufacturing of the components and the regulations of the handling itself were examined. (authors)

  2. Subretinal hyper-reflective material seen on optical coherence tomography as a biomarker for disease monitoring in age-related macular degeneration

    Science.gov (United States)

    Lee, H. B.; Ong, B. B.; Katta, M.; Yvon, C.; Lu, L.; Zakri, R.; Patel, N.

    2018-03-01

    Subretinal hyper-reflective material (SHRM) seen on optical coherence tomography (OCT) is thought to be a collection of fibrous tissues and vascular networks that are identified in age-related macular degeneration (ARMD). We have carried out a retrospective analysis of 91 OCT scans of neovascular ARMD subtypes including classic and occult choroidal neovascularization (CNV) and retinal angiomatous proliferation (RAP). All three subtypes received ranibizumab, an anti-vascular endothelial growth factor (Anti-VEGF) intravitreal injections on an as-needed basis following the loading doses. Volumes of SHRM were calculated using caliper measurements of maximal height and length of SHRM seen on OCT. The ellipsoid formula derived from tumour models was used to calculate the volume. It was found that occult CNV and RAP have larger SHRM volumes than those of classic CNV. SHRM volumes reduced overall following loading doses of Anti-VEGF injections at 4 months in all three subtypes. However, a rebound increase in volume was noticed in both occult CNV and RAP cohort at 12 months despite the initial, steeper reductions in the subtypes. These findings were consistent with the data seen in volume measurement using Topcon's automated segmentation algorithm in a smaller cohort of patients. We propose that SHRM should be used as a potential biomarker to quantify both disease progression and prognosis of neovascular ARMD alongside other conventional methods.

  3. A research project to develop and evaluate a technical education component on materials technology for orientation to space-age technology

    Science.gov (United States)

    Jacobs, J. A.

    1976-01-01

    A project was initiated to develop, implement, and evaluate a prototype component for self-pacing, individualized instruction on basic materials science. Results of this project indicate that systematically developed, self-paced instruction provides an effective means for orienting nontraditional college students and secondary students, especially minorities, to both engineering technology and basic materials science. In addition, students using such a system gain greater chances for mastering subject matter than with conventional modes of instruction.

  4. "That's Ratchet": A Chicana Feminist "Rasquache" Pedagogy as Entryway to Understanding the Material Realities of Contemporary Latinx Elementary-Aged Youth

    Science.gov (United States)

    Mendoza Aviña, Sylvia

    2016-01-01

    In line with this special issue's examination of theories of teaching and learning that are neither determined by nor isolated from restrictive spaces of learning, this essay introduces a Chicana feminist "rasquache" pedagogy. A Chicana feminist "rasquache" pedagogy is rooted in the everyday experiences and material realities…

  5. Potential of Glutathione Antioxidant in the Hippocampus Repair: Preliminary Study on Bioactive Materials Antiaging of Snakehead Fish (Channa striata in Animal Models of Aging

    Directory of Open Access Journals (Sweden)

    Sunarno Sunarno

    2014-12-01

    Full Text Available Snakehead fish meat contains active ingredients with anti-aging potential that serves as a precursor of glutathione. The ability of glutathione as an antiaging opportunities in the utilization of fish meat, especially snakehead fish. Snakehead fish meat contains several important amino acids, such as glutamine, cysteine​​, and glycine so the potential to be developed for the production of food that is nutritious and healthy. This study examines the essential amino acid composition of the antioxidant glutathione precursors found in snakehead fish from Rawa Pening Central Java to increase glutathione in the body and brain. The results showed that every 100g of snakehead fish meat from Rawa Pening containing glutamine (32.39%, cysteine ​​(6.61%, and glycine (9.69%. Snakehead fish meat extract given at a dose of 30 ml/kg/day in both types of animal models of aging effect on the increase in the content of glutathione and glutathione precursors, both in blood and hippocampus. Increased glutathione precursor of the most high to low, respectively glutamine, glycine, and cysteine​​. Availability of essential amino acids can support increased glutathione in the brain. This is indicated by an increase in glutathione hippocampus in both animal models, both on chronological aging or aging due to oxidative stress, respectively (0.822 and 0.359 mol/g bb compared to control tissue.

  6. Poly-epoxide lattices used for the coating of radioactive wastes: aging analysis in storage conditions and effects on the diffusional properties of materials

    International Nuclear Information System (INIS)

    Damian Pellissier, C.

    1999-01-01

    This work deals with the long term forecasting of the aging behaviour of epoxy-amine lattices used for the coating of radioactive wastes. In storage conditions, the oxygen of air, the radiations and the water are the three factors at the origin of the aging. The main goals have been to study the morphology changes during the aging and to model the oxidation phenomena. The transport properties allow to determine the oxygen diffusivities and solubilities. A wide range of poly-epoxide lattices has been studied, from the classical DGEBA/DDM classical lattice to the commercial coating matrix with contains both an important molar fraction of mono-epoxy and a plasticizer which lowers the vitreous transition temperature from 175 deg. C to 55 deg. C. The analysis of the diffusional parameters of these lattices shows that the solubility increases and the diffusivity decreases when the reticulation increases or when the lattice contains no plasticizer. The transport parameters necessary for the modeling laws have been determined for all lattices. The aging under thermo-activated air involves oxidation reactions which take place preferentially at the level of epoxy constituents and lead to the formation of carbonyl and amide polar oxygenated functions and to chain cleavage with the departure of phenol-type volatile products or higher mass compounds. Using a theoretical model, the hyperbolic-type oxide sites concentration profile has been precised and an important parameter, the thickness of the oxidized layer has been calculated. The radio-oxidation, performed in extreme conditions with respect to the real storage conditions, leads to the formation of polar functions without any significant degradation of lattices. The hygro-thermal aging is characterized, for the commercial matrix only, by the leaching possibility of various products initially present in the lattice and of hydrolysis products, and by the occurrence of osmotic pressure bags at the origin of cracks. This raises

  7. Geopolymer resin materials, geopolymer materials, and materials produced thereby

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Dong-Kyun; Medpelli, Dinesh; Ladd, Danielle; Mesgar, Milad

    2018-01-09

    A product formed from a first material including a geopolymer resin material, a geopolymer material, or a combination thereof by contacting the first material with a fluid and removing at least some of the fluid to yield a product. The first material may be formed by heating and/or aging an initial geopolymer resin material to yield the first material before contacting the first material with the fluid. In some cases, contacting the first material with the fluid breaks up or disintegrates the first material (e.g., in response to contact with the fluid and in the absence of external mechanical stress), thereby forming particles having an external dimension in a range between 1 nm and 2 cm.

  8. Electronic materials

    CERN Document Server

    Kwok, H L

    2010-01-01

    The electronic properties of solids have become of increasing importance in the age of information technology. The study of solids and materials, while having originated from the disciplines of physics and chemistry, has evolved independently over the past few decades. The classical treatment of solid-state physics, which emphasized classifications, theories and fundamental physical principles, is no longer able to bridge the gap between materials advances and applications. In particular, the more recent developments in device physics and technology have not necessarily been driven by new conc

  9. Effect of electron beam irradiation and microencapsulation on the flame retardancy of ethylene-vinyl acetate copolymer materials during hot water ageing test

    International Nuclear Information System (INIS)

    Sheng, Haibo; Zhang, Yan; Wang, Bibo; Yu, Bin; Shi, Yongqian; Song, Lei; Kundu, Chanchal Kumar; Tao, Youji; Jie, Ganxin; Feng, Hao; Hu, Yuan

    2017-01-01

    Microencapsulated ammonium polyphosphate (MCAPP) in combination with polyester polyurethane (TPU) was used to flame retardant ethylene-vinyl acetate copolymer (EVA). The EVA composites with different irradiation doses were immersed in hot water (80 °C) to accelerate ageing process. The microencapsulation and irradiation dose ensured positive impacts on the properties of the EVA composites in terms of better dimensional stability and flame retardant performance. The microencapsulation of APP could lower its solubility in water and the higher irradiation dose led to the more MCAPP immobilized in three dimensional crosslinked structure of the EVA matrix which could jointly enhance the flame retardant and electrical insulation properties of the EVA composites. So, the EVA composites with 180 kGy irradiation dose exhibited better dimensional stability than the EVA composites with 120 kGy due to the higher crosslinking degree. Moreover, the higher irradiation dose lead to the more MCAPP immobilizated in crosslinked three-dimensional structure of EVA, enhancing the flame retardancy and electrical insulation properties of the EVA composites. After ageing test in hot water at 80 °C for 2 weeks, the EVA/TPU/MCAPP composite with 180 kGy could still maintain the UL-94 V-0 rating and the limiting oxygen index (LOI) value was as high as 30%. This investigation indicated the flame retardant EVA cable containing MCAPP could achieve stable properties and lower electrical fire hazard risk during long-term hot water ageing test. - Highlights: • Microencapsulated ammonium polyphosphate is prepared by successive sol-gel process. • The higher irradiation dose induces the better dimensional stability for EVA system. • The higher irradiation, the more MCAPP immobilized in EVA crosslinked structure. • The higher irradiation dose enhances the flame retardancy of EVA composites. • The microencapsulated composites demonstrate stable flame retardancy in ageing test.

  10. Materials 2014: a great success for materials sector

    International Nuclear Information System (INIS)

    Isnard, Olivier; Crepin, Jerome

    2014-01-01

    In this work are presented the summaries of the 19 symposiums presented at the conference: 'Materials 2014' and whose topics were: eco-materials, materials for energy storage and conversion, strategic materials, rare elements and recycling, surfaces functionalization and physico-chemical characterization, interfaces and coatings, corrosion, aging, durability, damage mechanical behaviours, disordered materials, glasses and their functionalization, materials and health, functional materials, porous, granular and with a high surface area materials, nano-materials, nano-structured systems, assembling processes, carbonaceous materials, great instruments and studies of materials, materials in severe conditions, powder forming processes, metallic materials and structures lightening. (O.M.)

  11. Geopolymer resin materials, geopolymer materials, and materials produced thereby

    Science.gov (United States)

    Seo, Dong-Kyun; Medpelli, Dinesh; Ladd, Danielle; Mesgar, Milad

    2016-03-29

    A product formed from a first material including a geopolymer resin material, a geopolymer resin, or a combination thereof by contacting the first material with a fluid and removing at least some of the fluid to yield a product. The first material may be formed by heating and/or aging an initial geopolymer resin material to yield the first material before contacting the first material with the fluid. In some cases, contacting the first material with the fluid breaks up or disintegrates the first material (e.g., in response to contact with the fluid and in the absence of external mechanical stress), thereby forming particles having an external dimension in a range between 1 nm and 2 cm.

  12. Taking into account of the aging and the damage in the size determination of composite materials structures; Prise en compte du vieillissement et de l'endommagement dans le dimensionnement de structures en materiaux composites

    Energy Technology Data Exchange (ETDEWEB)

    Mercier, J

    2006-11-15

    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)

  13. Variations in battery life of a heart-lung machine using different pump speeds, pressure loads, boot material, centrifugal pump head, multiple pump usage, and battery age.

    LENUS (Irish Health Repository)

    Marshall, Cornelius

    2012-02-03

    Electrical failure during cardiopulmonary bypass (CPB) has previously been reported to occur in 1 of every 1500 cases. Most heart-lung machine pump consoles are equipped with built-in battery back-up units. Battery run times of these devices are variable and have not been reported. Different conditions of use can extend battery life in the event of electrical failure. This study was designed to examine the run time of a fully charged battery under various conditions of pump speed, pressure loads, pump boot material, multiple pump usage, and battery life. Battery life using a centrifugal pump also was examined. The results of this study show that battery life is affected by pump speed, circuit pressure, boot stiffness, and the number of pumps in service. Centrifugal pumps also show a reduced drain on battery when compared with roller pumps. These elements affect the longevity and performance of the battery. This information could be of value to the individual during power failure as these are variables that can affect the battery life during such a challenging scenario.

  14. A mechanical property and stress corrosion evaluation of VIM-ESR-VAR work strengthened and direct double aged Inconel 718 bar material

    Science.gov (United States)

    Montano, J. W.

    1986-01-01

    Presented are the mechanical properties and the stress corrosion resistance of triple melted vacuum induction melted (VIM), electro-slag remelted (ESR), and vacuum arc remelted (VAR), solution treated, work strengthened and direct double aged Inconel 718 alloy bars 4.00 in. (10.16) and 5.75 in. (14.60 cm) diameter. Tensile, charpy v-notched impact, and compact tension specimens were tested at ambient temperature in both the longitudinal and transverse directions. Longitudinal tensile and yield strengths in excess of 220 ksi (1516.85 MPa) and 200 ksi (1378.00 MPa) respectively, were realized at ambient temperature. Additional charpy impact and compact tension tests were performed at -100 F (-73 C). Longitudinal charpy impact strength equalled or exceeded 12.0 ft-lbs (16.3 Joules) at ambient and at -100 F(-73 C) while longitudinal compact (LC) tension fracture toughness strength remained above 79 ksi (86.80 MPa) at ambient and at -100 F(-73 C) temperatures. No failures occurred in the longitudinal or transverse tensile specimens stressed to 75 and 100 percent of their respective yield strengths and exposed to a salt fog environment for 180 days. Tensile tests performed after the stress corrosion test indicated no mechanical property degradation.

  15. Why Was Silcrete Heat-Treated in the Middle Stone Age? An Early Transformative Technology in the Context of Raw Material Use at Mertenhof Rock Shelter, South Africa.

    Directory of Open Access Journals (Sweden)

    Patrick Schmidt

    Full Text Available People heat treated silcrete during the Middle Stone Age (MSA in southern Africa but the spatial and temporal variability of this practice remains poorly documented. This paucity of data in turn makes it difficult to interrogate the motive factors underlying the application of this technique. In this paper we present data on heat treatment of silcrete through the Howiesons Poort and post-Howiesons Poort of the rock shelter site Mertenhof, located in the Western Cape of South Africa. In contrast to other sites where heat treatment has been documented, distance to rock source at Mertenhof can be reasonably well estimated, and the site is known to contain high proportions of a diversity of fine grained rocks including silcrete, hornfels and chert at various points through the sequence. Our results suggest the prevalence of heat treatment is variable through the sequence but that it is largely unaffected by the relative abundance of silcrete prevalence. Instead there is a strong inverse correlation between frequency of heat treatment in silcrete and prevalence of chert in the assemblage, and a generally positive correlation with the proportion of locally available rock. While it is difficult to separate individual factors we suggest that, at Mertenhof at least, heat treatment may have been used to improve the fracture properties of silcrete at times when other finer grained rocks were less readily available. As such, heat treatment appears to have been a component of the MSA behavioural repertoire that was flexibly deployed in ways sensitive to other elements of technological organisation.

  16. Aging Brain, Aging Mind.

    Science.gov (United States)

    Selkoe, Dennis J.

    1992-01-01

    Discusses the aging process related to physical changes of the human neural structure involved in learning, memory, and reasoning. Presents evidence that indicates such alterations do not necessarily signal the decline in cognitive function. Vignettes provide images of brain structures involved in learning, memory, and reasoning; hippocampal…

  17. In situ LA-ICPMS U–Pb dating of cassiterite without a known-age matrix-matched reference material: Examples from worldwide tin deposits spanning the Proterozoic to the Tertiary

    Science.gov (United States)

    Neymark, Leonid; Holm-Denoma, Christopher S.; Moscati, Richard J.

    2018-01-01

    Cassiterite (SnO2), a main ore mineral in tin deposits, is suitable for U–Pb isotopic dating because of its relatively high U/Pb ratios and typically low common Pb. We report a LA-ICPMS analytical procedure for U–Pb dating of this mineral with no need for an independently dated matrix-matched cassiterite standard. LA-ICPMS U-Th-Pb data were acquired while using NIST 612 glass as a primary non-matrix-matched standard. Raw data are reduced using a combination of Iolite™ and other off-line data reduction methods. Cassiterite is extremely difficult to digest, so traditional approaches in LA-ICPMS U-Pb geochronology that utilize well-characterized matrix-matched reference materials (e.g., age values determined by ID-TIMS) cannot be easily implemented. We propose a new approach for in situ LA-ICPMS dating of cassiterite, which benefits from the unique chemistry of cassiterite with extremely low Th concentrations (Th/U ratio of 10−4 or lower) in some cassiterite samples. Accordingly, it is assumed that 208Pb measured in cassiterite is mostly of non-radiogenic origin—it was initially incorporated in cassiterite during mineral formation, and can be used as a proxy for common Pb. Using 208Pb as a common Pb proxy instead of 204Pb is preferred as 204Pb is much less abundant and is also compromised by 204Hg interference during the LA-ICPMS analyses.Our procedure relies on 208Pb/206Pb vs 207Pb/206Pb (Pb-Pb) and Tera-Wasserburg 207Pb/206Pb vs 238U/206Pb (U-Pb) isochron dates that are calculated for a ~1.54 Ga low-Th cassiterite reference material with varying amounts of common Pb that we assume remained a closed U-Pb system. The difference between the NIST 612 glass normalized biased U-Pb date and the Pb-Pb age of the reference material is used to calculate a correction factor (F) for instrumental U-Pb fractionation. The correction factor (F) is then applied to measured U/Pb ratios and Tera-Wasserburg isochron dates are obtained for the unknown

  18. Energy materials

    CERN Document Server

    Bruce, Duncan W; Walton, Richard I

    2011-01-01

    In an age of global industrialisation and population growth, the area of energy is one that is very much in the public consciousness. Fundamental scientific research is recognised as being crucial to delivering solutions to these issues, particularly to yield novel means of providing efficient, ideally recyclable, ways of converting, transporting and delivering energy. This volume considers a selection of the state-of-the-art materials that are being designed to meet some of the energy challenges we face today. Topics are carefully chosen that show how the skill of the synthetic chemist can

  19. Do Bacteria Age?

    Indian Academy of Sciences (India)

    Bacteria are thought to be examples of organisms that do not age. They divide by .... carry genetic material to the next generation through the process of reproduction; they are also .... molecules, and modified proteins. This report revealed that ...

  20. 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

  1. Electrolytic polishing system for space age materials

    International Nuclear Information System (INIS)

    Coons, W.C.; Iosty, L.R.

    1976-01-01

    A simple electrolytic polishing technique was developed for preparing Cr, Co, Hf, Mo, Ni, Re, Ti, V, Zr, and their alloys for structural analysis on the optical microscope. The base electrolyte contains 5g ZnCl 2 and 15g AlCl 3 . 6H 2 O in 200 ml methyl alcohol, plus an amount of H 2 SO 4 depending on the metal being polished. Five etchants are listed

  2. Material Science

    Energy Technology Data Exchange (ETDEWEB)

    Won, Dong Yeon; Kim, Heung

    1987-08-15

    This book introduces material science, which includes key of a high-tech industry, new materials of dream like new metal material and semiconductor, classification of materials, microstructure of materials and characteristic. It mentions magic new materials such as shape memory alloy, fine ceramics, engineering fine ceramics, electronic ceramics, engineering plastic, glass, silicone conductor, optical fiber mixed materials and integrated circuit, challenge for new material and development of new materials.

  3. Material Science

    International Nuclear Information System (INIS)

    Won, Dong Yeon; Kim, Heung

    1987-08-01

    This book introduces material science, which includes key of a high-tech industry, new materials of dream like new metal material and semiconductor, classification of materials, microstructure of materials and characteristic. It mentions magic new materials such as shape memory alloy, fine ceramics, engineering fine ceramics, electronic ceramics, engineering plastic, glass, silicone conductor, optical fiber mixed materials and integrated circuit, challenge for new material and development of new materials.

  4. Materials and material testing

    International Nuclear Information System (INIS)

    Joergens, H.

    1978-01-01

    A review based on 105 literature quotations is given on the latest state of development in the steel sector and in the field of non-ferrous metals and plastics. The works quoted also include, preparation, working, welding including simulation methods, improvement of weldability, material mechanics (explanation of defects mechanisms by means of fracture mechanics), defect causes (corrosion, erosion, hydrogen influence), mechanical-technological and non-destructive material testing. Examples from the field of reactor building are also given within there topics. (IHOE) [de

  5. Age and Stress Prediction

    Science.gov (United States)

    2000-01-01

    Genoa is a software product that predicts progressive aging and failure in a variety of materials. It is the result of a SBIR contract between the Glenn Research Center and Alpha Star Corporation. Genoa allows designers to determine if the materials they plan on applying to a structure are up to the task or if alternate materials should be considered. Genoa's two feature applications are its progressive failure simulations and its test verification. It allows for a reduction in inspection frequency, rapid design solutions, and manufacturing with low cost materials. It will benefit the aerospace, airline, and automotive industries, with future applications for other uses.

  6. Active ageing technologies

    DEFF Research Database (Denmark)

    Lassen, Aske Juul

    In the recent decade the concept of active aging has become important in the Western hemisphere. The World Health Organization and The European Union have staged active aging as a core policy area and initiated programs of physical activity, independence and prolonged working lives among...... the elderly. As part of this rearticulation of old age, many new technologies take form. This paper uses a wide concept of technologies (devices, regimes, strategies and ways of doing) and argues that technologies form active aging subjectivities, and on the other hand, that these subjectivities...... in their socio-material practices form active aging. Hence, active aging is a mutual entanglement (Callon and Rabeharisoa 2004) between technologies, practices and subjectivities. The paper is based on four months of participant observations and 17 in-depth interviews with elderly persons conducted at three...

  7. Optical materials

    International Nuclear Information System (INIS)

    Poker, D.B.; Ortiz, C.

    1989-01-01

    This book reports on: Diamond films, Synthesis of optical materials, Structure related optical properties, Radiation effects in optical materials, Characterization of optical materials, Deposition of optical thin films, and Optical fibers and waveguides

  8. Ageing Polulations

    DEFF Research Database (Denmark)

    Christiansen, Terkel; Lauridsen, Jørgen Trankjær; Bech, Mickael

    2013-01-01

    An ageing society is characterised by an increasing median age of the population. The purpose of this chapter is to document the existing knowledge about the association between population ageing and health care expenditure, and to supplement this overview by a summary of our original research...... is that ageing as such can be expected only to a cause modest increase in health care expenditure per capita in the future. This conclusion is supported by our own empirical study, based on 15 EU countries....

  9. Skin Aging

    Science.gov (United States)

    Your skin changes as you age. You might notice wrinkles, age spots and dryness. Your skin also becomes thinner and loses fat, making it ... heal, too. Sunlight is a major cause of skin aging. You can protect yourself by staying out ...

  10. Communication & Aging.

    Science.gov (United States)

    Arnold, William E.

    This extensive bibliography contains more than 1,800 entries about communication and aging. The citations include journal articles, unpublished papers, speeches, dissertations, research studies, and books that relate aging and the aged to a variety of topics, including the following: physiological deterioration, socialization, political…

  11. Strategic Materials

    National Research Council Canada - National Science Library

    Buhler, Carl; Burke, Adrian; Davis, Kirk; Gerhard, Michelle; Heil, Valerie; Hulse, Richard; Kwong, Ralph; Mahoney, Michael; Moran, Scott; Peek, Michael

    2006-01-01

    Some materials possess greater value than others. Materials that provide essential support for the nation's economic viability or enable critical military capabilities warrant special attention in security studies...

  12. Active ageing

    Directory of Open Access Journals (Sweden)

    Frode F. Jacobsen

    2017-09-01

    Full Text Available Background: The concept of active ageing has been gaining prominence in the Nordic countries and beyond. This has been reflected in policy papers in Norway and other Nordic nations. Aims: The aim of this article is to analyse the topic of active ageing in five Norwegian White Papers (2002 to 2015 and discuss those policy documents in context of relevant research literature. Methods: A qualitative document analyses is employed focusing on how active ageing, and ageing in general, is described and which concepts are employed. No ethical approval was needed. Findings: The general theme of ageing and the specific theme of active ageing are increasingly prominent in the Norwegian White Papers studied. In all documents, some assumptions regarding ageing and active ageing seem implicit, such as independence being more important than (interdependence. ‘Productive’ activities like participation in working life are stressed, while others, like reading, watching TV or watching children playing in the street, are ignored. Conclusions: The policy documents demonstrate that the topic of active ageing is growing in importance. The documents increasingly seem to stress ‘productive’ activities – those related to working life, voluntary work or sports and physical training. They exclude activities that are meaningful for many older people, like watching their grandchildren play or reading books. Implications for practice: Practitioners in older people’s care could consider reflecting on: Government documents dealing with their own practice The prevalent concept of active ageing The trend of active ageing as a facilitating or hindering factor for good care work How present discourse on active ageing may influence their attitude towards frail older persons How they wish to relate to active ageing in their own practice

  13. Aging research

    International Nuclear Information System (INIS)

    Ross, D.F. Jr.

    1988-01-01

    The USNRC Office of Nuclear Regulatory Research has developed a program for nuclear plant aging research (NPAR) to achieve an understanding of nuclear plant aging, its potential effects on safety, and methods for its detection and mitigation, sufficient for addressing safety and regulatory issues and supporting regulatory decisions on issues. Specifically, the NRC has aggressive research and regulatory programs associated with aging effects on piping, steam generators, containments, structures, and electrical and mechanical systems and components. In addition to safety assessment for the original license period for nuclear power plants, this aging information will be extremely useful in providing technical bases for efficient and effective regulation associated with possible license extension. This paper discusses the major activities of USNRC sponsored aging research program and recommends an approach to manage and handle aging at nuclear power plants

  14. Materials Chemistry

    CERN Document Server

    Fahlman, Bradley D

    2011-01-01

    The 2nd edition of Materials Chemistry builds on the strengths that were recognized by a 2008 Textbook Excellence Award from the Text and Academic Authors Association (TAA). Materials Chemistry addresses inorganic-, organic-, and nano-based materials from a structure vs. property treatment, providing a suitable breadth and depth coverage of the rapidly evolving materials field. The 2nd edition continues to offer innovative coverage and practical perspective throughout. After briefly defining materials chemistry and its history, seven chapters discuss solid-state chemistry, metals, semiconducting materials, organic "soft" materials, nanomaterials, and materials characterization. All chapters have been thoroughly updated and expanded with, for example, new sections on ‘soft lithographic’ patterning, ‘click chemistry’ polymerization, nanotoxicity, graphene, as well as many biomaterials applications. The polymer and ‘soft’ materials chapter represents the largest expansion for the 2nd edition. Each ch...

  15. Successful ageing

    DEFF Research Database (Denmark)

    Kusumastuti, Sasmita; Derks, Marloes G. M.; Tellier, Siri

    2016-01-01

    BACKGROUND: Ageing is accompanied by an increased risk of disease and a loss of functioning on several bodily and mental domains and some argue that maintaining health and functioning is essential for a successful old age. Paradoxically, studies have shown that overall wellbeing follows a curvili...

  16. Ageing genes

    DEFF Research Database (Denmark)

    Rattan, Suresh

    2018-01-01

    The idea of gerontogenes is in line with the evolutionary explanation of ageing as being an emergent phenomenon as a result of the imperfect maintenance and repair systems. Although evolutionary processes did not select for any specific ageing genes that restrict and determine the lifespan...... of an individual, the term ‘gerontogenes’ primarily refers to any genes that may seem to influence ageing and longevity, without being specifically selected for that role. Such genes can also be called ‘virtual gerontogenes’ by virtue of their indirect influence on the rate and process of ageing. More than 1000...... virtual gerontogenes have been associated with ageing and longevity in model organisms and humans. The ‘real’ genes, which do influence the essential lifespan of a species, and have been selected for in accordance with the evolutionary life history of the species, are known as the longevity assurance...

  17. From cold power strategies to hot wars about raw materials? Game of chess of the world power between preventive war and futurable raw material politics in the age of the greenhouse; Von kalten Energiestrategien zu heissen Rohstoffkriegen? Schachspiel der Weltmaechte zwischen Praeventivkrieg und zukunftsfaehiger Rohstoffpolitik im Zeitalter des globalen Treibhauses

    Energy Technology Data Exchange (ETDEWEB)

    Roithner, T. (comp.)

    2008-07-01

    The 24th international summer academy, held in Stadtschlaining (Burgenland, Austria) between 8th July and 13th July, 2007, is engaged with the reasons to the conflicts and military conflicts at the end of the fossil energy age. The following lectures are held: (a) From cold power strategies to hot wars about raw materials? (Thomas Roithner); (b) Inauguration of the 24th international summer academy 2007 (Gerald Mader); (c) A change of consciousness also changes unconsciously the being (Hans Lukits); (d) Oil in fire - Conflicts of resources as a fuel for global discord (Wolfgang Sachs); (e) Safety discourses on both sides of the Atlantic - in times o peak oil and climatic change (Elmar Altvater); (f) From energy security to the war of resources: the resource politics of China, Russia and India (Andreas Zumach); (g) Why is there no alternative to the retreat from Afghanistan? (Peter Strutynski); (h) Do ''Peak Oil'' and nuclear energy solve the climate problem? (Helga Kromp-Kolb, Wolfgang kromp); (i) Water - the material from that conflicts consist? (Juerg Staudenmann, Karin Scheurer); (j) US strategy for the regions of Middle East and Caucasus in the unipolar world order (Matin Baraki); (k) What are the influences of oil on the conflict with Iran? (Udo Steinbach); (l) Geopolicy and resources: The grasp of the USA at Africa (Werner Ruf); (m) New colonization of Africa: China, USA and Europe in the struggle for resources (Karin Kneissl); (n) Securing resources and energy politics in Latin America: US politics, EU politics or independent world politics (Peter Stania); (o) More scarcely becoming raw materials - a source for armament and war planning? (Luehr Henken); (p) Battle groups - intervening groups for securing resources (Gunther Hauser); (q) Organization of the globalization as fateful question - which future lies before us? (Franz-Josef Radermacher); (r) No peace without change of renewable resources (Hermann Scheer); (s) Peaceable, forced or

  18. Successful Aging

    Directory of Open Access Journals (Sweden)

    Taufiqurrahman Nasihun

    2015-06-01

    Full Text Available The emerging concept of successful aging is based on evidence that in healthy individual when they get aged, there are  considerable variations in physiological functions alteration. Some people exhibiting greater, but others very few or no age related alteration. The first is called poor aging and the later is called successful pattern of aging (Lambert SW, 2008. Thus, in the simple words the successful aging concept is define as an opportunity of old people to stay  active and productive condition despite they get aged chronologically. Aging itself might be defined as the progressive accumulation of changes with time associated with or responsible for the ever-increasing susceptibility to disease and death which accompanies advancing age (Harman D, 1981. The time needed to accumulate changes is attributable to aging process. The marked emerging questions are how does aging happen and where does aging start? To answer these questions and because of the complexity of aging process, there are more than 300 aging theories have been proposed to explain how and where aging occured and started respectively. There are too many to enumerate theories and classification of aging process. In summary, all of these aging theories can be grouped into three clusters: 1. Genetics program theory, this theory suggests that aging is resulted from program directed by the genes; 2. Epigenetic theory, in these theory aging is resulted from environmental random events not determined by the genes; 3. Evolutionary theory, which propose that aging is a medium for disposal mortal soma in order to avoid competition between organism and their progeny for food and space, did not try to explain how aging occur, but possibly answer why aging occur (De la Fuente. 2009. Among the three groups of aging theories, the epigenetic theory is useful to explain and try to solve the enigma of aging which is prominently caused by internal and external environmental influences

  19. Contrast Materials

    Science.gov (United States)

    ... is mixed with water before administration liquid paste tablet When iodine-based and barium-sulfate contrast materials ... for patients with kidney failure or allergies to MRI and/or computed tomography (CT) contrast material. Microbubble ...

  20. Dirac materials

    OpenAIRE

    Wehling, T. O.; Black-Schaffer, A. M.; Balatsky, A. V.

    2014-01-01

    A wide range of materials, like d-wave superconductors, graphene, and topological insulators, share a fundamental similarity: their low-energy fermionic excitations behave as massless Dirac particles rather than fermions obeying the usual Schrodinger Hamiltonian. This emergent behavior of Dirac fermions in condensed matter systems defines the unifying framework for a class of materials we call "Dirac materials''. In order to establish this class of materials, we illustrate how Dirac fermions ...

  1. Magnetic Materials

    Science.gov (United States)

    Spaldin, Nicola A.

    2003-04-01

    Magnetic materials are the foundation of multi-billion dollar industries and the focus of intensive research across many disciplines. This book covers the fundamentals, basic theories and applications of magnetism and conventional magnetic materials. Based on a lecture course given by Nicola Spaldin in the Materials Department at University of California, Santa Barbara, the book is ideal for a one- semester course in magnetic materials. It contains numerous homework problems and solutions.

  2. Age Spots

    Science.gov (United States)

    ... for Every Season How to Choose the Best Skin Care Products In This Section Dermatologic Surgery What is dermatologic ... for Every Season How to Choose the Best Skin Care Products Age Spots Treatment Options Learn more about treatment ...

  3. Composite materials

    International Nuclear Information System (INIS)

    Sambrook, D.J.

    1976-01-01

    A superconductor composite is described comprising at least one longitudinally extending superconductor filament or bundle of sub-filaments, each filament or bundle of sub-filaments being surrounded by and in good electrical contact with a matrix material, the matrix material comprising a plurality of longitudinally extending cells of a metal of high electrical conductivity surrounded by a material of lower electrical conductivity. The high electrical conductivity material surrounding the superconducting filament or bundle of sub-filaments is interrupted by a radially extending wall of the material of the lower electrical conductivity, the arrangement being such that at least two superconductor filaments or sub-filaments are circumferentially circumscribed by a single annulus of the material of high electrical conductivity. The annulus is electrically interrupted by a radially extending wall of the material of low electrical conductivity

  4. Ageing of research reactors

    International Nuclear Information System (INIS)

    Ciocanescu, M.

    2001-01-01

    Historically, many of the research institutions were centred on a research reactor facility as main technological asset and major source of neutrons for research. Important achievements were made in time in these research institutions for development of nuclear materials technology and nuclear safety for nuclear energy. At present, ageing of nuclear research facilities among these research reactors and ageing of staff are considerable factors of reduction of competence in research centres. The safe way of mitigation of this trend deals with ageing management by so called, for power reactors, Plant Life Management and new investments in staff as investments in research, or in future resources of competence. A programmatic approach of ageing of research reactors in correlation with their actual and future utilisation, will be used as a basis for safety evaluation and future spending. (author)

  5. Aerospace materials and material technologies

    CERN Document Server

    Wanhill, R

    2017-01-01

    This book is a comprehensive compilation of chapters on materials (both established and evolving) and material technologies that are important for aerospace systems. It considers aerospace materials in three Parts. Part I covers Metallic Materials (Mg, Al, Al-Li, Ti, aero steels, Ni, intermetallics, bronzes and Nb alloys); Part II deals with Composites (GLARE, PMCs, CMCs and Carbon based CMCs); and Part III considers Special Materials. This compilation has ensured that no important aerospace material system is ignored. Emphasis is laid in each chapter on the underlying scientific principles as well as basic and fundamental mechanisms leading to processing, characterization, property evaluation and applications. A considerable amount of materials data is compiled and presented in appendices at the end of the book. This book will be useful to students, researchers and professionals working in the domain of aerospace materials.

  6. Nuclear power plant cable materials :

    Energy Technology Data Exchange (ETDEWEB)

    Celina, Mathias C.; Gillen, Kenneth T; Lindgren, Eric Richard

    2013-05-01

    A selective literature review was conducted to assess whether currently available accelerated aging and original qualification data could be used to establish operational margins for the continued use of cable insulation and jacketing materials in nuclear power plant environments. The materials are subject to chemical and physical degradation under extended radiationthermal- oxidative conditions. Of particular interest were the circumstances under which existing aging data could be used to predict whether aged materials should pass loss of coolant accident (LOCA) performance requirements. Original LOCA qualification testing usually involved accelerated aging simulations of the 40-year expected ambient aging conditions followed by a LOCA simulation. The accelerated aging simulations were conducted under rapid accelerated aging conditions that did not account for many of the known limitations in accelerated polymer aging and therefore did not correctly simulate actual aging conditions. These highly accelerated aging conditions resulted in insulation materials with mostly inert aging processes as well as jacket materials where oxidative damage dropped quickly away from the air-exposed outside jacket surface. Therefore, for most LOCA performance predictions, testing appears to have relied upon heterogeneous aging behavior with oxidation often limited to the exterior of the cable cross-section a situation which is not comparable with the nearly homogenous oxidative aging that will occur over decades under low dose rate and low temperature plant conditions. The historical aging conditions are therefore insufficient to determine with reasonable confidence the remaining operational margins for these materials. This does not necessarily imply that the existing 40-year-old materials would fail if LOCA conditions occurred, but rather that unambiguous statements about the current aging state and anticipated LOCA performance cannot be provided based on

  7. Computational materials design

    International Nuclear Information System (INIS)

    Snyder, R.L.

    1999-01-01

    Full text: Trial and error experimentation is an extremely expensive route to the development of new materials. The coming age of reduced defense funding will dramatically alter the way in which advanced materials have developed. In the absence of large funding we must concentrate on reducing the time and expense that the R and D of a new material consumes. This may be accomplished through the development of computational materials science. Materials are selected today by comparing the technical requirements to the materials databases. When existing materials cannot meet the requirements we explore new systems to develop a new material using experimental databases like the PDF. After proof of concept, the scaling of the new material to manufacture requires evaluating millions of parameter combinations to optimize the performance of the new device. Historically this process takes 10 to 20 years and requires hundreds of millions of dollars. The development of a focused set of computational tools to predict the final properties of new materials will permit the exploration of new materials systems with only a limited amount of materials characterization. However, to bound computational extrapolations, the experimental formulations and characterization will need to be tightly coupled to the computational tasks. The required experimental data must be obtained by dynamic, in-situ, very rapid characterization. Finally, to evaluate the optimization matrix required to manufacture the new material, very rapid in situ analysis techniques will be essential to intelligently monitor and optimize the formation of a desired microstructure. Techniques and examples for the rapid real-time application of XRPD and optical microscopy will be shown. Recent developments in the cross linking of the world's structural and diffraction databases will be presented as the basis for the future Total Pattern Analysis by XRPD. Copyright (1999) Australian X-ray Analytical Association Inc

  8. Materials Discovery | Materials Science | NREL

    Science.gov (United States)

    Discovery Materials Discovery Images of red and yellow particles NREL's research in materials characterization of sample by incoming beam and measuring outgoing particles, with data being stored and analyzed Staff Scientist Dr. Zakutayev specializes in design of novel semiconductor materials for energy

  9. Premature aging

    International Nuclear Information System (INIS)

    Sassaki, Hideo

    1992-01-01

    The hypothesis that radiation may accelerate aging phenomenon has been studied extensively, using the population of A-bomb survivors. In this paper, non-specific radiation-induced premature aging is discussed with a review of the literature. Cardiac lipofuscin, papillary fibrosis, aortic extensibility, hexamine/collagen ratio in the skin and aorta, testicular changes, giant hepatic cell nucleus, and neurofibril changes have so far been studied pathologically in the context of A-bomb radiation. Only testicular sclerosis has been found to correlate with distance from the hypocenter. Suggestive correlation was found to exist between the hexamine/collagen ratio in the skin and aorta and A-bomb radiation. Grip strength and hearing ability were decreased in the group of 100 rad and the group of 50-99 rad, respectively. The other physiological data did not definitely correlate with A-bomb radiation. Laboratory data, including erythrocyte sedimentation rate, α and β globulin levels, phytohemagglutinin reaction, T cell counts, erythrocyte glycophorin-A, the incidence of cerebral stroke, ischemic heart disease, and cataract were age-dependent and correlated with A-bomb radiation. These findings indicated that the occurrence of arteriosclerosis-related diseases, changes in immunological competence, and some pathological and physiological findings altered with advancing age, suggesting the correlation with A-bomb radiation. In general, it cannot be concluded that there is a positive correlation between A-bomb radiation and the premature aging. (N.K.) 51 refs

  10. Nano Materials

    International Nuclear Information System (INIS)

    Jin, In Ju; Lee, Ik Mo; Kwon, Yeung Gu

    2006-02-01

    This book introduces background of nano science such as summary, plenty room at the bottom, access way to nano technique, nanoparticles using bottom-up method which are a marvel of nature, and modern alchemy : chemical synthesis of artificial nano structure, understanding of quantum mechanics, STM/AFM, nano metal powder, ceramic nanoparticles, nano structure film, manufacture of nanoparticles using reverse micelle method, carbon nano tube, sol-gel material, nano energy material, nano catalyst nano bio material technology and spintronics.

  11. Material Systems

    DEFF Research Database (Denmark)

    Jensen, Mads Brath; Mortensen, Henrik Rubæk; Mullins, Michael

    2009-01-01

    This paper describes and reflects upon the results of an investigative project which explores the setting up of a material system - a parametric and generative assembly consisting of and taking into consideration material properties, manufacturing constraints and geometric behavior. The project...... approaches the subject through the construction of a logic-driven system aiming to explore the possibilities of a material system that fulfills spatial, structural and performative requirements concurrently and how these are negotiated in situations where they might be conflicting....

  12. Material focus

    DEFF Research Database (Denmark)

    Sokoler, Tomas; Vallgårda, Anna K. A.

    2009-01-01

    In this paper we build on the notion of computational composites, which hold a material perspective on computational technology. We argue that a focus on the material aspects of the technology could be a fruitful approach to achieve new expressions and to gain a new view on the technology's role...... in design. We study two of the computer's material properties: computed causality and connectability and through developing two computational composites that utilize these properties we begin to explore their potential expressions....

  13. Materializing Ethnography

    OpenAIRE

    Geismar, H.; Horst, H. A.

    2004-01-01

    The articles in this volume were originally presented in a panel entitled ‘Material Methodologies’ at the American Anthropological Association meeting in New Orleans (November 2002). The panel was devised to tie together theoretical advances in the study of the material with the creative possibilities of fieldwork practices. Through detailed ethnographic discussion, we highlighted the ways in which a focus on a specifically material world enabled us to discover new perspecti...

  14. Successful ageing

    DEFF Research Database (Denmark)

    Bülow, Morten Hillgaard; Söderqvist, Thomas

    2014-01-01

    Since the late 1980s, the concept of ‘ successful ageing’ has set the frame for discourse about contemporary ageing research. Through an analysis of the reception to John W. Rowe and Robert L. Kahn's launch of the concept of ‘ successful ageing’ in 1987, this article maps out the important themes...... and discussions that have emerged from the interdisciplinary field of ageing research. These include an emphasis on interdisciplinarity; the interaction between biology, psycho-social contexts and lifestyle choices; the experiences of elderly people; life-course perspectives; optimisation and prevention...... strategies; and the importance of individual, societal and scientific conceptualisations and understandings of ageing. By presenting an account of the recent historical uses, interpretations and critiques of the concept, the article unfolds the practical and normative complexities of ‘ successful ageing’....

  15. Materials characterisation

    International Nuclear Information System (INIS)

    Azali Muhammad

    2005-01-01

    Various nuclear techniques have been developed and employed by technologies and scientists worldwide to physically and chemically characterise the material particularly those that have applications in industry. These include small angle neutron scattering (SANS), x-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM) for the internal structural study of material, whereas, the x-ray fluorescence (XRF) for the chemical analysis, while the Moessbauer spectroscopy for the study on the magnetic properties and structural identity of material. Basic principle and instrumentations of the techniques are discussed in this chapter. Example of their applications in various disciplines particularly in characterisation of industrial materials also described

  16. Aging Differently

    DEFF Research Database (Denmark)

    Zajitschek, Felix; Jin, Tuo; Colchero, Fernando

    2014-01-01

    Diet effects on age-dependent mortality patterns are well documented in a large number of animal species, but studies that look at the effects of nutrient availability on late-life mortality plateaus are lacking. Here, we focus on the effect of dietary protein content (low, intermediate, and high...... based on Bayesian inference of age-specific mortality rates and found a deceleration of late-life mortality rates on all diets in males but only on the intermediate (standard) diet in females. The difference in mortality rate deceleration between males and females on extreme diets suggests...

  17. Aging Well

    DEFF Research Database (Denmark)

    Frieman, Catherine J.; Bruck, Joanna; Rebay-Salisbury, Katharina

    2017-01-01

    This article consist of several short individual articles which were solicited as responses to and reflections on Paul Treherne’s seminal meditation on Bronze Age male identity and warriorhood. Authors were asked to build on Treherne’s work and to reflect on how it had impacted their own research...

  18. Ice Ages

    Indian Academy of Sciences (India)

    that the precession of the earth's orbit caused ice ages. The precession of the earth's orbit leads to changes in the time of the year at which ... than in the southern hemisphere. ..... small increase in ocean temperature implies a large increase in.

  19. New materials

    International Nuclear Information System (INIS)

    Joshi, S.K.; Rao, C.N.R.; Tsuruta, T.

    1992-01-01

    The book contains the state-of-the art lectures delivered at the discussion meeting on new materials, a field in which rapid advances are taking place. The main objective of the meeting was to bring active scientists in this area from Japan and India together. The topics covered diverse aspects of modern materials including high temperature superconducting compounds. (M.G.B.)

  20. Materials science

    International Nuclear Information System (INIS)

    2002-01-01

    the document is a collection of papers on different aspects of materials science. It discusses many items such as semiconductors, surface properties and interfaces, construction and civil engineering, metallic materials, polymers and composites, biology and biomaterials, metallurgy etc.. - 1 - Document1 Document1

  1. Material Programming

    DEFF Research Database (Denmark)

    Vallgårda, Anna; Boer, Laurens; Tsaknaki, Vasiliki

    2017-01-01

    . Consequently we ask what the practice of programming and giving form to such materials would be like? How would we be able to familiarize ourselves with the dynamics of these materials and their different combinations of cause and effect? Which tools would we need and what would they look like? Will we program......, and color, but additionally being capable of sensing, actuating, and computing. Indeed, computers will not be things in and by themselves, but embedded into the materials that make up our surroundings. This also means that the way we interact with computers and the way we program them, will change...... these computational composites through external computers and then transfer the code them, or will the programming happen closer to the materials? In this feature we outline a new research program that floats between imagined futures and the development of a material programming practice....

  2. Composite material

    Science.gov (United States)

    Hutchens, Stacy A [Knoxville, TN; Woodward, Jonathan [Solihull, GB; Evans, Barbara R [Oak Ridge, TN; O'Neill, Hugh M [Knoxville, TN

    2012-02-07

    A composite biocompatible hydrogel material includes a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa. A calcium comprising salt is disposed in at least some of the pores. The porous polymer matrix can comprise cellulose, including bacterial cellulose. The composite can be used as a bone graft material. A method of tissue repair within the body of animals includes the steps of providing a composite biocompatible hydrogel material including a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa, and inserting the hydrogel material into cartilage or bone tissue of an animal, wherein the hydrogel material supports cell colonization in vitro for autologous cell seeding.

  3. Materials science

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    The Materials Science Division is engaged in research on physical properties of materials and the effects of radiation upon them. This involves solid state materials undergoing phase transitions, energy storing materials, and biomaterials. The Division also offers research facilities for M.S. and Ph.D. thesis work in the fields of physics, chemistry, materials, and radiation sciences in cooperation with the various colleges and departments of the UPR Mayaguez Campus. It is anticipated that it will serve as a catalyst in starting energy-related research programs in cooperation with UPR faculty, especially programs involving solar energy. To encourage and promote cooperative efforts, contact is maintained with former graduate students and with visiting scientists from Latin American research institutions

  4. Touching Materiality

    DEFF Research Database (Denmark)

    Rasmussen, Lisa Rosén

    2012-01-01

    Dripping ink pens, colourful paint on skin, vegetables pots on a school roof. In interviews with three generations of former school pupils, memories of material objects bore a relation to everyday school life in the past. Interwoven, these objects entered the memorising processes, taking...... the interviewer and interviewee beyond an exclusively linguistic understanding of memory. This article analyses how the shifting objects of materiality in personal and generational school memories connects to material as well as sensuous experiences of everyday school life and its complex processes of learning....... Drawing on anthropological writings, the article argues that the objects of materiality are part of important but non-verbalised memories of schooling. The Dutch philosopher Eelco Runia’s notions of presence and metonymy are incorporated as tools for approaching objects of materiality in memory studies....

  5. Skeletal Aging and Osteoporosis Biomechanics and Mechanobiology

    CERN Document Server

    2013-01-01

    The focus of this book is on mechanical aspects of skeletal fragility related to aging and osteoporosis. Topics include: Age-related changes in trabecular structure and strength; age-related changes in cortical material properties; age-related changes in whole-bone structure; predicting bone strength and fracture risk using image-based methods and finite element analysis; animal models of osteoporosis and aging; age-related changes in skeletal mechano responsiveness; exercise and physical interventions for osteoporosis.

  6. Aging Perspectives

    OpenAIRE

    Theodore D Cosco; David Brehme; Nora Grigoruta; Lisa-Katrin Kaufmann; Liis Lemsalu; Ruth Meex; Angela Schuurmans; Neslihan Sener

    2014-01-01

    Despite the proliferation of successful ageing (SA) research, the literature is dominated by researcher-driven Anglophone conceptualisations. To date, lay perspectives of SA have not been examined in Europe or Turkey. The current study aims to conduct a mixed-methods examination of conceptualisations of SA in seven underrepresented countries. Using snowball sampling via social media sites, an online survey consisting of established closed-ended and open-ended items – translated into seven lan...

  7. Healthy ageing

    DEFF Research Database (Denmark)

    Harrison, Adrian Paul; Brüggemann, Dagmar Adeline; Bartels, Else Marie

    2009-01-01

    The study employed mechanical stretching in vitro of sections of abdominal aorta of elderly mice to investigate any benefits of oral treatment with alpha-ketoglutarate (AKG) on arterial elasticity. Eighteen female mice (50-weeks-old) were assigned to a control (2% w/v) Na2-AKG or (2% w/v) a Ca-AK...... investigation as a candidate for therapies targeting arterial stiffening with age....

  8. Golden Age

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

      Sometimes, a moment can announce the end of an age. The gold market is like that. Within two transaction days, the gold slumped by 13%and saw a 25%tumble from the high point in August 2011. According to the classic investment theory, a 20%-above decline means the shift from“a bull”to“a bear”market.   The super bear market of gold has lasted a dozen years. But the bull-to-bear shift was completed within only 20 minutes. Wall Street’s analysts and ordinary Chinese people had different understandings to the golden age.   Expecting a bear market, Wall Street continuously dumped gold, resulting in a diving of gold price. Seeing the benefits, leisure Chinese madams made a gold rush, causing a slight bounce of gold price. On April 23, renowned investment bank Goldman Sachs suspended the short sale. So,“Chinese aunts”beating back Wall Street’s analysts became the hottest topic online for the time being.   What are the decisive factors for the crash of gold price? Will the gold market complete a real bull-to-bear shift? Will the golden age of gold be farther or nearer?

  9. Dielectric materials for electrical engineering

    CERN Document Server

    Martinez-Vega, Juan

    2013-01-01

    Part 1 is particularly concerned with physical properties, electrical ageing and modeling with topics such as the physics of charged dielectric materials, conduction mechanisms, dielectric relaxation, space charge, electric ageing and life end models and dielectric experimental characterization. Part 2 concerns some applications specific to dielectric materials: insulating oils for transformers, electrorheological fluids, electrolytic capacitors, ionic membranes, photovoltaic conversion, dielectric thermal control coatings for geostationary satellites, plastics recycling and piezoelectric poly

  10. Material Modelling - Composite Approach

    DEFF Research Database (Denmark)

    Nielsen, Lauge Fuglsang

    1997-01-01

    is successfully justified comparing predicted results with experimental data obtained in the HETEK-project on creep, relaxation, and shrinkage of very young concretes cured at a temperature of T = 20^o C and a relative humidity of RH = 100%. The model is also justified comparing predicted creep, shrinkage......, and internal stresses caused by drying shrinkage with experimental results reported in the literature on the mechanical behavior of mature concretes. It is then concluded that the model presented applied in general with respect to age at loading.From a stress analysis point of view the most important finding...... in this report is that cement paste and concrete behave practically as linear-viscoelastic materials from an age of approximately 10 hours. This is a significant age extension relative to earlier studies in the literature where linear-viscoelastic behavior is only demonstrated from ages of a few days. Thus...

  11. Nuclear materials

    International Nuclear Information System (INIS)

    1996-01-01

    In 1998, Nuclear Regulatory Authority of the Slovak Republic (NRA SR) performed 38 inspections, 25 of them were performed in co-operation with IAEA inspectors. There is no fresh nuclear fuel at Bohunice A-1 NPP at present. Fresh fuel of Bohunice V-1 and V-2 NPPs is inspected in the fresh fuel storage.There are 327 fresh fuel assemblies in Mochovce NPP fresh fuel storage. In addition to that, are also 71 small users of nuclear materials in Slovakia. In most cases they use: covers made of depleted uranium for non-destructive works, detection of level in production plants, covers for therapeutical sources at medical facilities. In. 1995, NRA SR issued 4 new licences for nuclear material withdrawal. In the next part manipulation with nuclear materials, spent fuel stores and illegal trafficking in nuclear materials are reported

  12. Composite Materials

    DEFF Research Database (Denmark)

    Nielsen, Lauge Fuglsang

    This book deals with the mechanical and physical behavior of composites as influenced by composite geometry. "Composite Materials" provides a comprehensive introduction for researchers and students to modern composite materials research with a special emphasis on the significance of phase geometry......, viscoelastic behavior, and internal stress states. Other physical properties considered are thermal and electrical conductivities, diffusion coefficients, dielectric constants and magnetic permeability. Special attention is given to the effect of pore shape on the mechanical and physical behavior of porous....... The book enables the reader to a better understanding of the behavior of natural composites, improvement of such materials, and design of new materials with prescribed properties. A number of examples are presented: Special composite properties considered are stiffness, shrinkage, hygro-thermal behavior...

  13. Hazardous materials

    Science.gov (United States)

    ... substances that could harm human health or the environment. Hazardous means dangerous, so these materials must be ... M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health ...

  14. Utopian Materialities

    DEFF Research Database (Denmark)

    Elgaard-Jensen, Torben

    2004-01-01

    In various ways, this paper makes the counter-intuitive claim that the utopian and the material are thoroughlyinterdependent, rather than worlds apart. First, through a reading of Thomas More's Utopia, it is argued thatUtopia is the product of particular kinds of relations, rather than merely...... a detachment from the known world.Second, the utopianism of a new economy firm is examined. It is argued that the physical set-up of the firm -in particular the distribution of tables and chairs - evoke a number of alternatives to ordinary work practice.In this way the materialities of the firm are crucial...... to its persuasive image of being the office of the future.The notion that utopia is achieved through material arrangements is finally related to the analysis of facts andfictions in ANT. It is argued, that even though Utopias are neither fact nor fiction, they are both material andeffective...

  15. Propulsion materials

    Energy Technology Data Exchange (ETDEWEB)

    Wall, Edward J. [U.S. Dept. of Energy, Washington, D.C. (United States); Sullivan, Rogelio A. [U.S. Dept. of Energy, Washington, D.C. (United States); Gibbs, Jerry L. [U.S. Dept. of Energy, Washington, D.C. (United States)

    2008-01-01

    The Department of Energy’s (DOE’s) Office of Vehicle Technologies (OVT) is pleased to introduce the FY 2007 Annual Progress Report for the Propulsion Materials Research and Development Program. Together with DOE national laboratories and in partnership with private industry and universities across the United States, the program continues to engage in research and development (R&D) that provides enabling materials technology for fuel-efficient and environmentally friendly commercial and passenger vehicles.

  16. Encountering Materiality

    DEFF Research Database (Denmark)

    Svabo, Connie

    2016-01-01

    DHT researcher Connie Svabo and artist Charlotte Grum did a joint performance presentation titled Becoming Sheep, Becoming Animal at the international conference Encountering Materiality – Transdisciplinary Conversations, held in Geneve, Schwitzerland, June 23-25 2016.......DHT researcher Connie Svabo and artist Charlotte Grum did a joint performance presentation titled Becoming Sheep, Becoming Animal at the international conference Encountering Materiality – Transdisciplinary Conversations, held in Geneve, Schwitzerland, June 23-25 2016....

  17. Background Material

    DEFF Research Database (Denmark)

    Zandersen, Marianne; Hyytiäinen, Kari; Saraiva, Sofia

    This document serves as a background material to the BONUS Pilot Scenario Workshop, which aims to develop harmonised regional storylines of socio-ecological futures in the Baltic Sea region in a collaborative effort together with other BONUS projects and stakeholders.......This document serves as a background material to the BONUS Pilot Scenario Workshop, which aims to develop harmonised regional storylines of socio-ecological futures in the Baltic Sea region in a collaborative effort together with other BONUS projects and stakeholders....

  18. Aging Perspectives

    Directory of Open Access Journals (Sweden)

    Theodore D Cosco

    2014-05-01

    Full Text Available Despite the proliferation of successful ageing (SA research, the literature is dominated by researcher-driven Anglophone conceptualisations. To date, lay perspectives of SA have not been examined in Europe or Turkey. The current study aims to conduct a mixed-methods examination of conceptualisations of SA in seven underrepresented countries. Using snowball sampling via social media sites, an online survey consisting of established closed-ended and open-ended items – translated into seven languages – was administered. Grounded theory methods and descriptive statistics were used to analyse qualitative and quantitative data, respectively.

  19. Science, technology and the ‘grand challenge’ of ageing—Understanding the socio-material constitution of later life : Science, Technology and the “Grand Challenge” of Ageing

    NARCIS (Netherlands)

    Peine, Alex; Faulkner, Alex; Jæger, Birgit; Moors, Ellen

    Abstract In this paper, we introduce the themes addressed and the approaches used in this special issue. We start by briefly discussing the state of the art in research and policy making related to science, technology and ageing. We argue that an important gap characterizes this state of the art:

  20. Adhesive dental materials

    International Nuclear Information System (INIS)

    Unlu, N.

    2005-01-01

    Two main classes of material are involved, the glass-ionomer cements and the composite resins. This investigation describes the way they are bonded to the tooth and highlights their differences. Glass ionomers develop a zone of interaction with the tooth as they age which ultimately gives an extremely strong bond, and results in excellent retention rates. By contrast, bonding of composite resins is more complicated and possibly less effective, though these materials have better wear resistance and better aesthetics than glass ionomers. Assessment of bond durability is difficult. This is because a dental restorative can fail by a number of mechanisms apart from de bonding: for example, through wear or fracture

  1. Structural Materials: 95. Concrete

    International Nuclear Information System (INIS)

    Naus, Dan J.

    2012-01-01

    Nuclear power plant concrete structures and their materials of construction are described, and their operating experience noted. Aging and environmental factors that can affect the durability of the concrete structures are identified. Basic components of a program to manage aging of these structures are identified and described. Application of structural reliability theory to devise uniform risk-based criteria by which existing facilities can be evaluated to achieve a desired performance level when subjected to uncertain demands and to quantify the effects of degradation is outlined. Finally, several areas are identified where additional research is desired.

  2. Aging Blepharoplasty

    Directory of Open Access Journals (Sweden)

    Inchang Cho

    2013-09-01

    Full Text Available In performing upper blepharoplasty in the elderly, looking younger and keeping the eyelidsharmonious with the rest of the face have to be achieved at the same time. The most importantgoal in upper blepharoplasty for aging is correcting the drooping upper eyelid skin, and inthis process, the surgeon may or may not create a double eyelid fold. The pros and cons haveto be fully discussed with the patient, but the author personally prefers creating a doublefold unless the patient refuses, because it is efficient in correcting and preventing furtherdrooping of the skin. In most patients, the brow is elevated to compensate for the droopingeyelid, and when the drooping is corrected, brow ptosis may ensue. The surgeon has to preparefor these consequences before performing the procedure, and estimate the exact amountof skin to be excised. In the elderly, the skin and the orbicularis oculi muscle is thin, with adecreased amount of subcutaneous fat and retro-orbicularis oculi fat, and in most cases,excision of the skin alone is enough to correct the deformity. Removing large portions ofsoft tissue may also prolong the recovery period. Unlike younger patients, the lower skinflap should not be stretched too much in the elderly, as it may create an aggressive lookingappearance. A few wrinkles in the lower flap should remain untouched to create a naturallook. In this article, the author’s own methods of performing an aging blepharoplasty aredescribed specifically, with a step-by-step guide and surgical tips.

  3. Cable aging management

    International Nuclear Information System (INIS)

    Anandkumaran, A.; Sedding, H.

    2012-01-01

    Worldwide, due to the age of the majority of nuclear generating stations significant attention is being paid to the condition of the major components, e.g., reactor, steam generator, turbine generator, transformer, etc., with respect to relicensing and life extension. However, there is recognition that cable systems are critical to the safe, reliable and economic operation of nuclear power plants. Consequently, there is great interest in ageing management of low and medium voltage cables in the nuclear environment. Successful implementation of such programs requires an understanding of how the materials associated with cables and their accessories behave under normal operating and accident conditions. However, there is also a great need to determine the actual condition of the materials and systems in order to make rational decisions on whether or not to replace cables to ensure long term assurance of reliable operation. This proposed contribution describes an approach to cable ageing management of low and medium voltage cables based on measurements of material and electrical properties obtained in the laboratory and in the field. The effectiveness of various chemical, mechanical and electrical test methods are discussed in the context of, • Cable configuration, i.e., low or medium voltage, shielded or unshielded • Material type, i.e., PVC, XLPE, EPR, etc., • Ageing stress, i.e., electrical, thermal, radiation, thermal plus radiation, etc. These factors are key to identifying the most appropriate test method (or methods) to enable understanding of the current condition of the cable. While electrical test methods, e.g., ac withstand testing, partial discharge and various dielectric loss measurement techniques have been found effective for medium voltage cables, they are of very limited use on low voltage cables that constitute the majority of cables in nuclear power plants. This limited effectiveness is due to the lack of a well defined ground plane that is a

  4. Materials behaviour in PWRs core

    International Nuclear Information System (INIS)

    Barbu, A.; Massoud, J.P.

    2008-01-01

    Like in any industrial facility, the materials of PWR reactors are submitted to mechanical, thermal or chemical stresses during particularly long durations of operation: 40 years, and even 60 years. Materials closer to the nuclear fuel are submitted to intense bombardment of particles (mainly neutrons) coming from the nuclear reactions inside the core. In such conditions, the damages can be numerous and various: irradiation aging, thermal aging, friction wear, generalized corrosion, stress corrosion etc.. The understanding of the materials behaviour inside the cores of reactors in operation is a major concern for the nuclear industry and its long term forecast is a necessity. This article describes the main ways of materials degradation without and under irradiation, with the means used to foresee their behaviour using physics-based models. Content: 1 - structures, components and materials: structure materials, nuclear materials; 2 - main ways of degradation without irradiation: thermal aging, stress corrosion, wear; 3 - main ways of degradation under irradiation: microscopic damaging - point defects, dimensional alterations, evolution of mechanical characteristics under irradiation, irradiation-assisted stress corrosion cracking (IASCC), synergies; 4 - forecast of materials evolution under irradiation using physics-based models: primary damage - fast dynamics, primary damage annealing - slow kinetics microstructural evolution, impact of microstructural changes on the macroscopic behaviour, insight on modeling methods; 5 - materials change characterization techniques: microscopic techniques - direct defects observation, nuclear techniques using a particle beam, global measurements, mechanical characterizations; 6 - perspectives. (J.S.)

  5. Layered materials

    Science.gov (United States)

    Johnson, David; Clarke, Simon; Wiley, John; Koumoto, Kunihito

    2014-06-01

    Layered compounds, materials with a large anisotropy to their bonding, electrical and/or magnetic properties, have been important in the development of solid state chemistry, physics and engineering applications. Layered materials were the initial test bed where chemists developed intercalation chemistry that evolved into the field of topochemical reactions where researchers are able to perform sequential steps to arrive at kinetically stable products that cannot be directly prepared by other approaches. Physicists have used layered compounds to discover and understand novel phenomena made more apparent through reduced dimensionality. The discovery of charge and spin density waves and more recently the remarkable discovery in condensed matter physics of the two-dimensional topological insulating state were discovered in two-dimensional materials. The understanding developed in two-dimensional materials enabled subsequent extension of these and other phenomena into three-dimensional materials. Layered compounds have also been used in many technologies as engineers and scientists used their unique properties to solve challenging technical problems (low temperature ion conduction for batteries, easy shear planes for lubrication in vacuum, edge decorated catalyst sites for catalytic removal of sulfur from oil, etc). The articles that are published in this issue provide an excellent overview of the spectrum of activities that are being pursued, as well as an introduction to some of the most established achievements in the field. Clusters of papers discussing thermoelectric properties, electronic structure and transport properties, growth of single two-dimensional layers, intercalation and more extensive topochemical reactions and the interleaving of two structures to form new materials highlight the breadth of current research in this area. These papers will hopefully serve as a useful guideline for the interested reader to different important aspects in this field and

  6. Aging Gracefully.

    Science.gov (United States)

    Waldorf, Heidi A

    2017-06-01

    At the Annual Meeting of the American Academy of Dermatology in 2016, I directed the symposium entitled ‘Aging Gracefully’ for the second time. The symposium’s primary learning objective was to give the audience a framework for managing aesthetic patients. In the last decade, there has been a significant increase in the options for and availability of noninvasive and minimally invasive rejuvenation. With that has been an associated surge in interest by physicians and patients. And, as the number of procedures across the globe increases, so too do the number of aesthetically poor outcomes. Most come from practitioners doing paint-by-numbers treatment. As experts in skin biology and treatment, dermatologists should practice the highest-level cosmetic as well as general dermatology. The faculty presented information to aid practitioners how best to approach patients and formulate a cosmetic plan. The faculty discussed important considerations based on patient gender, age, and skin type. Updated information on the science of cosmeceuticals and the benefits of early noninvasive intervention was presented as were next generation devices and alternatives to standard therapies. The faculty have kindly condensed their AAD presentations for this supplement. I thank L’Oréal and the Journal of Drugs in Dermatology for giving us the opportunity to present this information to a wider audience in this e-supplement. Heidi A. Waldorf MD Director of Laser & Cosmetic Dermatology, The Mount Sinai Hospital, New York, NY Icahn School of Medicine of Mount Sinai, New York, NY Waldorf Dermatology Aesthetics, Nanuet, NY

  7. Aging Blepharoplasty

    Directory of Open Access Journals (Sweden)

    Inchang Cho

    2013-09-01

    Full Text Available In performing upper blepharoplasty in the elderly, looking younger and keeping the eyelids harmonious with the rest of the face have to be achieved at the same time. The most important goal in upper blepharoplasty for aging is correcting the drooping upper eyelid skin, and in this process, the surgeon may or may not create a double eyelid fold. The pros and cons have to be fully discussed with the patient, but the author personally prefers creating a double fold unless the patient refuses, because it is efficient in correcting and preventing further drooping of the skin. In most patients, the brow is elevated to compensate for the drooping eyelid, and when the drooping is corrected, brow ptosis may ensue. The surgeon has to prepare for these consequences before performing the procedure, and estimate the exact amount of skin to be excised. In the elderly, the skin and the orbicularis oculi muscle is thin, with a decreased amount of subcutaneous fat and retro-orbicularis oculi fat, and in most cases, excision of the skin alone is enough to correct the deformity. Removing large portions of soft tissue may also prolong the recovery period. Unlike younger patients, the lower skin flap should not be stretched too much in the elderly, as it may create an aggressive looking appearance. A few wrinkles in the lower flap should remain untouched to create a natural look. In this article, the author's own methods of performing an aging blepharoplasty are described specifically, with a step-by-step guide and surgical tips.

  8. Materials design and development of functional materials for industry

    International Nuclear Information System (INIS)

    Asahi, Ryoji; Morikawa, Takeshi; Hazama, Hirofumi; Matsubara, Masato

    2008-01-01

    It is now well recognized that we are witnessing a golden age of innovation with novel materials, with discoveries that are important for both basic science and industry. With the development of theory along with computing power, quantum materials design-the synthesis of materials with the desired properties in a controlled way via materials engineering on the atomic scale-is becoming a major component of materials research. Computational prediction based on first-principles calculations has helped to find an efficient way to develop materials that are much needed for industry, as we have seen in the successful development of visible-light sensitized photocatalysts and thermoelectric materials. Close collaboration between theory and experiment is emphasized as an essential for success

  9. Supplementary Material

    Indian Academy of Sciences (India)

    mraga

    1. Supplementary Material. A soluble-lead Redox Flow Battery with corrugated graphite sheet and reticulated vitreous carbon as positive and negative current collectors by A Banerjee et al (pp 163-. 170). Figure S1. SEM images for bare substrates: (a) graphite sheet, (b) 20 ppi RVC, (c) 30 ppi. RVC and (d) 45 ppi RVC.

  10. Emerging Materiality

    DEFF Research Database (Denmark)

    Bertelsen, Olav Wedege; Breinbjerg, Morten; Pold, Søren

    2009-01-01

    The authors examine how materiality emerges from complex chains of mediation in creative software use. The primarily theoretical argument is inspired and illustrated by interviews with two composers of electronic music. The authors argue that computer mediated activity should not primarily be und...

  11. Atmospheric materiality

    DEFF Research Database (Denmark)

    Wieczorek, Izabela

    2016-01-01

    experience and, consequently, to the conceptual and methodological shifts in the production of space, and hence in the way we think about materiality. In this context, architectural space is understood as a contingent construction – a space of engagement that appears to us as a result of continuous...

  12. Absorbant materials

    International Nuclear Information System (INIS)

    Quetier, Monique.

    1978-11-01

    Absorbants play a very important part in the nuclear industry. They serve for the control, shut-down and neutron shielding of reactors and increase the capacity of spent fuel storage pools and of special transport containers. This paper surveys the usual absorbant materials, means of obtainment, their essential characteristics relating to their use and their behaviour under neutron irradiation [fr

  13. Friction Material Composites Materials Perspective

    CERN Document Server

    Sundarkrishnaa, K L

    2012-01-01

    Friction Material Composites is the first of the five volumes which strongly educates and updates engineers and other professionals in braking industries, research and test labs. It explains besides the formulation of design processes and its complete manufacturing input. This book gives an idea of mechanisms of friction and how to control them by designing .The book is  useful for designers  of automotive, rail and aero industries for designing the brake systems effectively with the integration of friction material composite design which is critical. It clearly  emphasizes the driving  safety and how serious designers should  select the design input. The significance of friction material component like brake pad or a liner as an integral part of the brake system of vehicles is explained. AFM pictures at nanolevel illustrate broadly the explanations given.

  14. Materials Science

    Science.gov (United States)

    2003-01-01

    The Materials Science Program is structured so that NASA s headquarters is responsible for the program content and selection, through the Enterprise Scientist, and MSFC provides for implementation of ground and flight programs with a Discipline Scientist and Discipline Manager. The Discipline Working Group of eminent scientists from outside of NASA acts in an advisory capacity and writes the Discipline Document from which the NRA content is derived. The program is reviewed approximately every three years by groups such as the Committee on Microgravity Research, the National Materials Advisory Board, and the OBPR Maximization and Prioritization (ReMaP) Task Force. The flight program has had as many as twenty-six principal investigators (PIs) in flight or flight definition stage, with the numbers of PIs in the future dependent on the results of the ReMaP Task Force and internal reviews. Each project has a NASA-appointed Project Scientist, considered a half-time job, who assists the PI in understanding and preparing for internal reviews such as the Science Concept Review and Requirements Definition Review. The Project Scientist also insures that the PI gets the maximum science support from MSFC, represents the PI to the MSFC community, and collaborates with the Project Manager to insure the project is well-supported and remains vital. Currently available flight equipment includes the Materials Science Research Rack (MSRR-1) and Microgravity Science Glovebox. Ground based projects fall into one or more of several categories. Intellectual Underpinning of Flight Program projects include theoretical studies backed by modeling and computer simulations; bring to maturity new research, often by young researchers, and may include preliminary short duration low gravity experiments in the KC-135 aircraft or drop tube; enable characterization of data sets from previous flights; and provide thermophysical property determinations to aid PIs. Radiation Shielding and preliminary In

  15. Magnetocaloric materials

    Energy Technology Data Exchange (ETDEWEB)

    Jeppesen, Stinus

    2008-10-15

    New and improved magnetocaloric materials are one of the cornerstones in the development of room temperature magnetic refrigeration. Magnetic refrigeration has been used since the 1930ies in cryogenic applications, but has since the discovery of room temperature refrigerants received enormous attention. This Ph.D. work has been mainly concerned with developing a new technique to characterize the magnetocaloric effect (MCE) and using this technique in the investigations on new and improved magnetocaloric materials. For this purpose a novel differential scanning calorimeter (DSC) with applied magnetic fields was developed for measuring heat capacity as function of magnetic field. Measurements using the developed DSC demonstrate a very high sensitivity, fast measurements and good agreement with results obtained by other techniques. Furthermore, two material systems have been described in this work. Both systems take basis in the mixed-valence manganite system La{sub 1-x}Ca{sub x}MnO{sub 3} well known from research on colossal magnetoresistance (CMR). The mixed-valence manganite crystallizes in the perovskite structure of general formula ABO{sub 3}. The first material system is designed to investigate the influence of low level Cu doping on the B-site. Six different samples were prepared with over-stoichiometric compositions La{sub 0.67}Ca{sub 0.33}Mn{sub 1.05}Cu{sub x}O{sub 3}, x=0, 1, 2, 3, 4 and 5%. All compositions crystallized well in the same perovskite structure, but the morphology of the samples changed drastically with doping. Investigation on the magnetocaloric properties revealed that small levels of Cu up to around 3% could improve the magnetocaloric performance of the materials. Furthermore, Cu could be used to tune the temperature interval without deteriorating the MCE, which is a much desired characteristic for potential use in magnetic refrigerators. A less comprehensive part of the work has been concerned with the investigation of doping on the A

  16. Materializing Superghosts

    OpenAIRE

    Alexandrov, Victor; Krotov, Dmitry; Losev, Andrei; Lysov, Vyacheslav

    2007-01-01

    We construct the off-shell BV realization of N=1, d=10 SYM with 7 auxillary fields. This becomes possible due to materialized ghost phenomenon. Namely, supersymmetry ghosts are coordinates on a manifold B of 10-dimensional spinors with pure spinors cut out. Auxillary fields are sections of a bundle over B, and supersymmetry transformations are nonlinear in ghosts. By integrating out axillary fields we obtain on-shell supersymmetric BV action with terms quadratic in antifields. Exactly this on...

  17. Material monitoring

    International Nuclear Information System (INIS)

    Kotter, W.; Zirker, L.; Hancock, J.A.

    1995-01-01

    Waste Reduction Operations Complex (WROC) facilities are located at the Idaho National Engineering Laboratory (INEL). The overall goal for the Pollution Prevention/Waste Minimization Unit is to identify and establish the correct amount of waste generated so that it can be reduced. Quarterly, the INEL Pollution Prevention (P2) Unit compares the projected amount of waste generated per process with the actual amount generated. Examples of waste streams that would be addresses for our facility would include be are not limited to: Maintenance, Upgrades, Office and Scrap Metal. There are three potential sources of this variance: inaccurate identification of those who generate the waste; inaccurate identification of the process that generates the waste; and inaccurate measurement of the actual amount generated. The Materials Monitoring Program was proposed to identify the sources of variance and reduce the variance to an acceptable level. Prior to the implementation of the Material Monitoring Program, all information that was gathered and recorded was done so through an informal estimation of waste generated by various personnel concerned with each processes. Due to the inaccuracy of the prior information gathering system, the Material Monitoring Program was established. The heart of this program consists of two main parts. In the first part potential waste generators provide information on projected waste generation process. In the second part, Maintenance, Office, Scrap Metal and Facility Upgrade wastes from given processes is disposed within the appropriate bin dedicated to that process. The Material Monitoring Program allows for the more accurate gathering of information on the various waste types that are being generated quarterly

  18. Thermoelectric Materials

    Science.gov (United States)

    Gao, Peng; Berkun, Isil; Schmidt, Robert D.; Luzenski, Matthew F.; Lu, Xu; Bordon Sarac, Patricia; Case, Eldon D.; Hogan, Timothy P.

    2014-06-01

    Mg2(Si,Sn) compounds are promising candidate low-cost, lightweight, nontoxic thermoelectric materials made from abundant elements and are suited for power generation applications in the intermediate temperature range of 600 K to 800 K. Knowledge on the transport and mechanical properties of Mg2(Si,Sn) compounds is essential to the design of Mg2(Si,Sn)-based thermoelectric devices. In this work, such materials were synthesized using the molten-salt sealing method and were powder processed, followed by pulsed electric sintering densification. A set of Mg2.08Si0.4- x Sn0.6Sb x (0 ≤ x ≤ 0.072) compounds were investigated, and a peak ZT of 1.50 was obtained at 716 K in Mg2.08Si0.364Sn0.6Sb0.036. The high ZT is attributed to a high electrical conductivity in these samples, possibly caused by a magnesium deficiency in the final product. The mechanical response of the material to stresses is a function of the elastic moduli. The temperature-dependent Young's modulus, shear modulus, bulk modulus, Poisson's ratio, acoustic wave speeds, and acoustic Debye temperature of the undoped Mg2(Si,Sn) compounds were measured using resonant ultrasound spectroscopy from 295 K to 603 K. In addition, the hardness and fracture toughness were measured at room temperature.

  19. Application of the concrete aging model to the case of cracked materials and to the coupling with the mechanical properties; Application du modele de degradation du beton au cas des milieux fissures et au couplage avec la mecanique

    Energy Technology Data Exchange (ETDEWEB)

    Torrenti, J.M.; Adenot, F.; Tognazzi, C. [CEA/Saclay, 91 - Gif-sur-Yvette (France); Tognazzi, C. [Toulouse Univ., 31 (France). LMDC; Danese, S. [Ecole Nationale Superieure des Arts et Industries de Strasbourg, 67 - Strasbourg (France); Poyet, S. [Ecole Nationale Superieure de Cachan, 94 (France)

    1998-07-01

    Predicting the long-term behavior of concrete used in radioactive waste disposal requires the knowledge of the effects of constantly renewed water on its chemistry and its coupling with the mechanical properties. In contact with water, concrete undergoes chemical degradation. This degradation influences the mechanical performance of the material as well as cracks could interfere with the chemical degradation. This paper shows how these problems can be treated using the Ca{sup ++} concentration in pore solution as the state variable that conducts the evolution of chemical, physical and mechanical properties. Some comparisons with experimental results are shown. Finally, the problem of the numerical simulation of accelerated tests of cracked samples is discussed. (authors)

  20. High-Precision Plutonium Isotopic Compositions Measured on Los Alamos National Laboratory’s General’s Tanks Samples: Bearing on Model Ages, Reactor Modelling, and Sources of Material. Further Discussion of Chronometry

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, Khalil J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rim, Jung Ho [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Porterfield, Donivan R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Roback, Robert Clifford [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Boukhalfa, Hakim [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Stanley, Floyd E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-06-29

    In this study, we re-analyzed late-1940’s, Manhattan Project era Plutonium-rich sludge samples recovered from the ''General’s Tanks'' located within the nation’s oldest Plutonium processing facility, Technical Area 21. These samples were initially characterized by lower accuracy, and lower precision mass spectrometric techniques. We report here information that was previously not discernable: the two tanks contain isotopically distinct Pu not only for the major (i.e., 240Pu, 239Pu) but trace (238Pu ,241Pu, 242Pu) isotopes. Revised isotopics slightly changed the calculated 241Am-241Pu model ages and interpretations.

  1. FOREWORD: Materials metrology Materials metrology

    Science.gov (United States)

    Bennett, Seton; Valdés, Joaquin

    2010-04-01

    It seems that so much of modern life is defined by the materials we use. From aircraft to architecture, from cars to communications, from microelectronics to medicine, the development of new materials and the innovative application of existing ones have underpinned the technological advances that have transformed the way we live, work and play. Recognizing the need for a sound technical basis for drafting codes of practice and specifications for advanced materials, the governments of countries of the Economic Summit (G7) and the European Commission signed a Memorandum of Understanding in 1982 to establish the Versailles Project on Advanced Materials and Standards (VAMAS). This project supports international trade by enabling scientific collaboration as a precursor to the drafting of standards. The VAMAS participants recognized the importance of agreeing a reliable, universally accepted basis for the traceability of the measurements on which standards depend for their preparation and implementation. Seeing the need to involve the wider metrology community, VAMAS approached the Comité International des Poids et Mesures (CIPM). Following discussions with NMI Directors and a workshop at the BIPM in February 2005, the CIPM decided to establish an ad hoc Working Group on the metrology applicable to the measurement of material properties. The Working Group presented its conclusions to the CIPM in October 2007 and published its final report in 2008, leading to the signature of a Memorandum of Understanding between VAMAS and the BIPM. This MoU recognizes the work that is already going on in VAMAS as well as in the Consultative Committees of the CIPM and establishes a framework for an ongoing dialogue on issues of materials metrology. The question of what is meant by traceability in the metrology of the properties of materials is particularly vexed when the measurement results depend on a specified procedure. In these cases, confidence in results requires not only traceable

  2. Alloy materials

    Energy Technology Data Exchange (ETDEWEB)

    Hans Thieme, Cornelis Leo (Westborough, MA); Thompson, Elliott D. (Coventry, RI); Fritzemeier, Leslie G. (Acton, MA); Cameron, Robert D. (Franklin, MA); Siegal, Edward J. (Malden, MA)

    2002-01-01

    An alloy that contains at least two metals and can be used as a substrate for a superconductor is disclosed. The alloy can contain an oxide former. The alloy can have a biaxial or cube texture. The substrate can be used in a multilayer superconductor, which can further include one or more buffer layers disposed between the substrate and the superconductor material. The alloys can be made a by process that involves first rolling the alloy then annealing the alloy. A relatively large volume percentage of the alloy can be formed of grains having a biaxial or cube texture.

  3. Casting materials

    Science.gov (United States)

    Chaudhry, Anil R [Xenia, OH; Dzugan, Robert [Cincinnati, OH; Harrington, Richard M [Cincinnati, OH; Neece, Faurice D [Lyndurst, OH; Singh, Nipendra P [Pepper Pike, OH

    2011-06-14

    A foam material comprises a liquid polymer and a liquid isocyanate which is mixed to make a solution that is poured, injected or otherwise deposited into a corresponding mold. A reaction from the mixture of the liquid polymer and liquid isocyanate inside the mold forms a thermally collapsible foam structure having a shape that corresponds to the inside surface configuration of the mold and a skin that is continuous and unbroken. Once the reaction is complete, the foam pattern is removed from the mold and may be used as a pattern in any number of conventional casting processes.

  4. Construction material

    Science.gov (United States)

    Wagh, Arun S [Orland Park, IL; Antink, Allison L [Bolingbrook, IL

    2008-07-22

    A structural material of a polystyrene base and the reaction product of the polystyrene base and a solid phosphate ceramic is applied as a slurry which includes one or more of a metal oxide or a metal hydroxide with a source of phosphate to produce a phosphate ceramic and a poly (acrylic acid or acrylate) or combinations or salts thereof and polystyrene or MgO applied to the polystyrene base and allowed to cure so that the dried aqueous slurry chemically bonds to the polystyrene base. A method is also disclosed of applying the slurry to the polystyrene base.

  5. Ageing management of concrete structure

    International Nuclear Information System (INIS)

    Parthipan, P.; Ramaprasad, G.S.; Senthil, R.

    2006-01-01

    It is a generally accepted fact that while designing a concrete structure the durability parameters of construction materials should be evaluated as carefully as possible like other properties such as mechanical, physical and chemical properties. No material is inherently durable as result of environmental interaction with microstructure and consequently, the properties of the materials change with time due to weathering action, chemical attack, abrasion or any mode of degradation. The main cause of ageing on structure, water, which is primary for both creation and destruction on many natural materials. In porous materials, water creates different types of physical and chemical process of degradation. The water movement through porous materials are controlled by the permeability of the respective materials. The rate of deterioration is affected by type of concentration of ions present in the water and chemical deposition of materials. Controlling weathering action, chemical attack, abrasion and selecting good quality construction material and methods of construction can increase the service life of the structure. (author)

  6. Photographic materials

    International Nuclear Information System (INIS)

    Jamieson, P.B.

    1980-01-01

    Radiographic films based on silver halides are normally handled under red or orange safelights to prevent fogging due to their sensitivity to white light. The present invention relates to ultraviolet radiation sensitive material which can be handled under virtually white light without significant fogging. The film material is comprised of a base having at least one layer of a photographic silver halide emulsion and a yellow filter dye screening the emulsion from visible radiation. The silver halide emulsion contains 50-100 mole % of silver chloride, the higher the silver chloride content, the lower the visible light sensitivity. The nature and properties of the yellow filter dye are described. When recording an X-ray image, the film is loaded into the camera under white safelight conditions from which light of wavelength shorter than 400 nm is excluded. The film is in contact with one or more phosphor screens capable when struck by X-rays of emitting ultraviolet radiation, the screens having a peak ultraviolet emission within the wavelength range of 250-380 nm. After X-ray exposure, the film is removed and developed. Two examples illustrating the invention are given. (U.K.)

  7. Coating materials

    International Nuclear Information System (INIS)

    Ozeki, Takao; Kimura, Tadashi; Kobayashi, Juichi; Maeda, Yutaka; Nakamoto, Hideo.

    1969-01-01

    A non-solvent type coating material composition having properties as good as thermosetting acrylic or amino alkid resins is provided by employing active energy irradiation, particularly electron beams, using a radically polymerizable low molecular compound (A) (hereafter called an oligomer) containing at least two vinyl radicals in one molecule. This oligomer is produced by reacting an epoxy-containing vinyl monomer with alpha-, beta-ethylene unsaturated carboxylic acids or their anhydrides. The composition (I) contains 10% - 100% of this oligomer. In embodiments, an oligomer having a fiberous trivinyl construction is produced by reacting 180 parts by weight of glycidyl methacrylate ester with 130 parts of itaconic acid in the presence of a polymerization-inhibitor and an addition reaction catalyst at 90 0 C for 6 hours. In practice, the coating material compositions (1), consist of the whole oligomer [I-1]; (2), consist of 10-90% of (A) component and 90%-10% of vinyl monomers containing at least 30% (meth) acrylic monomer [I-2]; (3), 10%-90% of component (A) and 90%-10% of other monomers containing at least two vinyl radicals [I-3]; (4), a mixture of (I-2) and (I-3), [I-4]; and (5), consist of 50% or less unsaturated polyester of 500-5,000 molecular weight range or drying oil, or alkyd resin of 500-5,000 molecular weight range modified by drying oil, [I-5]. As a catalyst a tertiary amino vinyl compound is preferred. Five examples are given. (Iwakiri, K.)

  8. Functional materials

    International Nuclear Information System (INIS)

    Park, J. Y.; Hong, G. W.; Lee, H. J.

    2002-05-01

    Development of fabrication process of functional ceramic materials, evaluation of characteristics and experiments for understanding of irradiation behavior of ceramics were carried out for application of ceramics to the nuclear industry. The developed processes were the SiC surface coating technology with large area for improvement of wear resistance and corrosion resistance, the fabrication technology of SiC composites for excellent irradiation resistance, performance improvement technology of SiC fiber and nano-sized powder processing by combustion ignition and spray. Typical results were CVD SiC coating with diameter of 25cm and thickness of 100μm, highly dense SiC composite by F-CVI, heat-treating technology of SiC fiber using B4C power, and nano-sized powders of ODS-Cu, Li-based breeding materials, Ni-based metal powders with primary particle diameter of 20∼50nm. Furthermore, test equipment, data productions and damage evaluations were performed to understand corrosion resistance and wear resistance of alumina, silicon carbide and silicon nitride under PWR or PHWR operation conditions. Experimental procedures and basic technologies for evaluation of irradiation behavior were also established. Additionally, highly reactive precursor powders were developed by various technologies and the powders were applied to the fabrication of 100 m long Ag/Bi-2223 multi-filamentary wires. High Tc magnets and fly wheel for energy storage were developed, as well

  9. [Ageing and work: technical standards].

    Science.gov (United States)

    De Vito, G; Riva, M A; Meroni, R; Cesana, G C

    2010-01-01

    Over the last few years, studies on the relationship between ageing and work have attracted growing interest due to the increased probability among workers of developing major health problems as a consequence of ageing of the working population. Negative outcomes for health are possible when an age-related imbalance appears between physical workload and physical work capacity. Interventions based on workload reductions should help to keep workers on the job for as long as allowed by law. Reference masses by age and sex are suggested by the technical standards of the ISO 11228 series, which are also quoted by Italian law D.Lgs. 81/2008, and EN 1005 series, which recommend limits valid also for manual material handling, and pushing and pulling. Decreasing low back pain prevalence or recurrence, in an ageing population with high prevalence of back disorders, could be more effective than many other approaches to enhance workers' quality of life and consequently maintain and improve workers' performance.

  10. Materials compatibility information data bank

    International Nuclear Information System (INIS)

    Mead, K.E.

    1977-01-01

    A major concern in the design of weapons systems is the compatibility of the materials used with each other and with the enclosed environment. Usually these systems require long term storage with a high reliability for proper function at the end of this storage period. Materials selection is then based on both past experience and laboratory accelerated aging experiments to assure this long term reliability. To assist in the task of materials selection a computerized materials compatibility data bank is being established. This data bank will provide a source of annotated information and references to personnel and documents for both the designer and materials engineer to draw on for guidance in materials selection. The data bank storage and information retrieval philosophy will be discussed and procedures for information gathering outlined. Examples of data entries and search routines will be presented to demonstrate the usefulness and versatility of the proposed system

  11. PETN Coarsening - Predictions from Accelerated Aging Data

    Energy Technology Data Exchange (ETDEWEB)

    Maiti, Amitesh [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gee, Richard H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2011-03-30

    Ensuring good ignition properties over long periods of time necessitates maintaining a good level of porosity in powders of initiator materials and preventing particle coarsening. To simulate porosity changes of such powder materials over long periods of time a common strategy is to perform accelerated aging experiments over shorter time spans at elevated temperatures. In this paper we examine historical accelerated-aging data on powders of Pentaerythritol Tetranitrate (PETN), an important energetic material, and make predictions for long-term aging under ambient conditions. Lastly, we develop an evaporation-condensation- based model to provide some mechanistic understanding of the coarsening process.

  12. Virtual materiality

    DEFF Research Database (Denmark)

    Søndergaard, Dorte Marie

    as their recounts of them and 3. the consumption of other media products like movies, reality shows, YouTube videos etc. How do we theorize ‘matter’ in such dimensions? Is it possible to theorize virtual matter as ‘materiality’ in line with any real life materiality? What conceptualization will help us understand......? These questions become crucial when we follow matter in and across real life, virtual experience, recounted imagery, night dreams, YouTube videos and even further. Some may already have recognized Phillip’s skeleton army as a transport/transformation from Lord of the Rings, DVD 3, the army which Aragon calls out....... Butler, J. (1993) Bodies that Matter. On the Discursive Limits of “Sex”. London: Routledge. Durkin, K. et al. (1998) Children, Media and Agression. Current Research in Australia and New Zealand. In: Carlson, U. & von Feilitzen, C. (red): Children and Media Violence. Yearbook from the UNESCO International...

  13. Photographic materials

    International Nuclear Information System (INIS)

    1980-01-01

    Radiographic films based on silver halides are normally handled under red or orange safelights to prevent fogging due to their sensitivity to white light. The present invention relates to ultraviolet radiation sensitive material which can be handled under virtually white light without significant fogging. A photographic, chemically sensitised silver halide emulsion is described, containing 50-100 mole % of silver chloride, the higher the silver chloride content, the lower the visible light sensitivity. The remaining silver halide, if any, is silver bromide and/or silver iodide. The silver halide grains are grown in the presence of ammonia, an excess of chloride ions and tetraazaindene growth controller. Examples illustrating the invention are given. (U.K.)

  14. Summary of JAPEIC age program

    International Nuclear Information System (INIS)

    Miyoshi, S.; Maeda, N.; Yamaguchi, A.

    1992-01-01

    Japan Power Engineering and Inspection Corporation (JAPEIC) is a statutory foundation charged with responsibility of enhancing thermal and nuclear power plant quality. JAPEIC performs construction and pre-service inspections as well as periodic inspections of many types of power plants including nuclear, gas turbine and internal combustion systems. In 1987 a research center was established to permit the systematic examination of advanced inspection technologies. One of the Structural Materials in Use for commercial Nuclear Power Plants provides the link to this workshop. The project is also referred to as the Aging General Evaluation (AGE) project. The AGE project is a six year, multi-task effort addressing material condition monitoring. One set of tasks emphasizes instrumentation simulation tasks to aid in application and utilization. All tasks are in their initial phases. The program is described in this paper

  15. Photovoltaic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Duty, C.; Angelini, J.; Armstrong, B.; Bennett, C.; Evans, B.; Jellison, G. E.; Joshi, P.; List, F.; Paranthaman, P.; Parish, C.; Wereszczak, A.

    2012-10-15

    The goal of the current project was to help make the US solar industry a world leader in the manufacture of thin film photovoltaics. The overall approach was to leverage ORNL’s unique characterization and processing technologies to gain a better understanding of the fundamental challenges for solar cell processing and apply that knowledge to targeted projects with industry members. ORNL has the capabilities in place and the expertise required to understand how basic material properties including defects, impurities, and grain boundaries affect the solar cell performance. ORNL also has unique processing capabilities to optimize the manufacturing process for fabrication of high efficiency and low cost solar cells. ORNL recently established the Center for Advanced Thin-film Systems (CATS), which contains a suite of optical and electrical characterization equipment specifically focused on solar cell research. Under this project, ORNL made these facilities available to industrial partners who were interested in pursuing collaborative research toward the improvement of their product or manufacturing process. Four specific projects were pursued with industrial partners: Global Solar Energy is a solar industry leader in full scale production manufacturing highly-efficient Copper Indium Gallium diSelenide (CIGS) thin film solar material, cells and products. ORNL worked with GSE to develop a scalable, non-vacuum, solution technique to deposit amorphous or nanocrystalline conducting barrier layers on untextured stainless steel substrates for fabricating high efficiency flexible CIGS PV. Ferro Corporation’s Electronic, Color and Glass Materials (“ECGM”) business unit is currently the world’s largest supplier of metallic contact materials in the crystalline solar cell marketplace. Ferro’s ECGM business unit has been the world's leading supplier of thick film metal pastes to the crystalline silicon PV industry for more than 30 years, and has had operational

  16. Regulatory good practices relating to monitoring and assessment of ageing nuclear power plants. A compilation of the 1991/92 Peer Group discussion considerations as they relate to operational plants. Working material

    International Nuclear Information System (INIS)

    1993-01-01

    In 1974 the IAEA established a Nuclear Safety Standards (NUSS) programme within which 5 Codes and 55 Safety Guides have been produced in the areas of Governmental Organization, Siting, Design, Operation and Quality Assurance. The NUSS Codes and Guides are a collection of basic and derived requirements for the safety of nuclear power plants with thermal neutron reactors. They have been developed in such a manner as to ensure the broadest international consensus. This broad consensus is one of the reasons for the relatively general wording of the main principles and sometimes causes problems when these principles are applied in the design of nuclear power plants. The requirements, particularly those of the Codes, often need interpretation in specific cases. In many areas national regulations and technical standards are available, but often these leave some questions unanswered and their practical application on a case-by-case basis is necessary. To assist in the application and interpretation of the NUSS Safety Standards and Safety Guides, the preparation of a number of Safety Practices publications has been commenced. Ibis publication is intended to assist regulators and also operating organizations. It is a compilation of the reports of the 1991/92 Peer Group discussions which considered regulatory good practices relating to monitoring and assessment of the ageing of nuclear power plants. Therefore names of participated countries in this documents are those at time of 1991/92 Peer Group discussions. It identifies those common regulatory features which require continuous reinforcement and examples of good regulatory practices that were recommended by senior regulators in the Peer Group discussions. The purpose of this publication is to provide a compilation of the 1991/92 Peer Group discussions relating to operational plant. This document the covers practices in the 20 countries participating in this round of Peer Group discussions. The document is a synopsis of

  17. Regulatory good practices relating to monitoring and assessment of ageing nuclear power plants. A compilation of the 1991/92 Peer Group discussion considerations as they relate to operational plants. Working material

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1993-07-01

    In 1974 the IAEA established a Nuclear Safety Standards (NUSS) programme within which 5 Codes and 55 Safety Guides have been produced in the areas of Governmental Organization, Siting, Design, Operation and Quality Assurance. The NUSS Codes and Guides are a collection of basic and derived requirements for the safety of nuclear power plants with thermal neutron reactors. They have been developed in such a manner as to ensure the broadest international consensus. This broad consensus is one of the reasons for the relatively general wording of the main principles and sometimes causes problems when these principles are applied in the design of nuclear power plants. The requirements, particularly those of the Codes, often need interpretation in specific cases. In many areas national regulations and technical standards are available, but often these leave some questions unanswered and their practical application on a case-by-case basis is necessary. To assist in the application and interpretation of the NUSS Safety Standards and Safety Guides, the preparation of a number of Safety Practices publications has been commenced. Ibis publication is intended to assist regulators and also operating organizations. It is a compilation of the reports of the 1991/92 Peer Group discussions which considered regulatory good practices relating to monitoring and assessment of the ageing of nuclear power plants. Therefore names of participated countries in this documents are those at time of 1991/92 Peer Group discussions. It identifies those common regulatory features which require continuous reinforcement and examples of good regulatory practices that were recommended by senior regulators in the Peer Group discussions. The purpose of this publication is to provide a compilation of the 1991/92 Peer Group discussions relating to operational plant. This document the covers practices in the 20 countries participating in this round of Peer Group discussions. The document is a synopsis of

  18. Tritium Storage Material

    International Nuclear Information System (INIS)

    Cowgill, Donald F.; Luo, Weifang; Smugeresky, John E.; Robinson, David B.; Fares, Stephen James; Ong, Markus D.; Arslan, Ilke; Tran, Kim L.; McCarty, Kevin F.; Sartor, George B.; Stewart, Kenneth D.; Clift, W. Miles

    2008-01-01

    Nano-structured palladium is examined as a tritium storage material with the potential to release beta-decay-generated helium at the generation rate, thereby mitigating the aging effects produced by enlarging He bubbles. Helium retention in proposed structures is modeled by adapting the Sandia Bubble Evolution model to nano-dimensional material. The model shows that even with ligament dimensions of 6-12 nm, elevated temperatures will be required for low He retention. Two nanomaterial synthesis pathways were explored: de-alloying and surfactant templating. For de-alloying, PdAg alloys with piranha etchants appeared likely to generate the desired morphology with some additional development effort. Nano-structured 50 nm Pd particles with 2-3 nm pores were successfully produced by surfactant templating using PdCl salts and an oligo(ethylene oxide) hexadecyl ether surfactant. Tests were performed on this material to investigate processes for removing residual pore fluids and to examine the thermal stability of pores. A tritium manifold was fabricated to measure the early He release behavior of this and Pd black material and is installed in the Tritium Science Station glove box at LLNL. Pressure-composition isotherms and particle sizes of a commercial Pd black were measured.

  19. Biointegrating Materials

    Science.gov (United States)

    Amédée, J.; Bordenave, L.; Durrieu, M.-C.; Fricain, J.-C.; Pothuaud, L.

    The extraordinary increase in human longevity explains the growing need for replacement organs. The remarkable successes of conventional transplants (associated with the development of effective antirejection drugs and improved control of their administration) are also accompanied by certain drawbacks. First on the list is an inadequate supply of replacement organs: the number of candidates for transplants grows larger, opposition to the removal of organs increases, and the number of transplants has reached a ceiling. Furthermore, it has come to light over the past few years that organ transplants carry a significant risk of transmitting pathogens. Finally, the main drawback lies in the need to pursue an immunosuppression treatment. Scientists and doctors have long been in search of alternatives to human organ transplants. According to the definition drawn up in Chester in 1986 at the Consensus Conference organised under the aegis of the European Society for Biomaterials, biomaterials are non-viable materials used in a medical device and destined to interact with biological systems, whether they contribute to the constitution of a diagnostic device, a tissue or organ substitute, or a device designed to provide functional assistance or replacement.

  20. Coating materials

    International Nuclear Information System (INIS)

    Ozeki, Takao; Kimura, Tadashi; Kobayashi, Juichi; Maeda, Yutaka; Nakamoto, Hideo.

    1969-01-01

    A non-solvent type coating material composition is provided which can be hardened by irradiation with active energy, particularly electron beams, using a composition which contains 10%-100% of a radically polymerizable low molecular compound (A), (hereafter called an oligomer), having at least two vinyl radicals in one molecule. These compositions have a high degree of polymerization and characteristics equivalent to thermosetting acrylic or amino alkyd resin. The oligomer (A) is produced by reacting an epoxy-containing vinyl monomer with saturated polycarboxylic acids or anhydrides. In one embodiment, 146 parts by weight of adipic acid and 280 parts of glycidyl methacrylate ester undergo addition reaction in the presence of a polymerization-inhibitor and a catalyst at 90 0 C for 6 hours to produce an oligomer having a fiberous divinyl construction. The coating composition utilizes this oligomer in the forms of (I-1), a whole oligomer; (I-2), 0%-90% of this oligomer and 90%-10% of a vinyl monomer containing at least 30% of (meth) acrylic monomer; (I-3), 10%-90% of such oligomer and 90%-10% of other monomers containing at least two vinyl radicals in one molecule; (I-4), a mixture of (I-2) and (I-3) in proportion of 1/9 to 9/1, and (I-5), above four compositions each containing 50% or less unsaturated polyester or drying oil having 500-5,000 molecules or a drying oil-modified alkyd resin having 500-5,000 molecules. Four examples are given. (Iwakiri, K.)

  1. On aging factors, aging mechanisms and their combinations in the primary circuit of NPPs

    International Nuclear Information System (INIS)

    Varga, T.; Brumovsky, M.

    1993-01-01

    Ageing is the dominating problem of elder nuclear power plant (NPP) components but still can not be neglected even for the newest ones. Ageing may express itself in different ways: irradiated steel parts may become embrittled, chromium alloy steels may decompose, fatigue life may become exhausted so that cracks may be formed and finally, corrosion attack may result in stress corrosion cracking. However, even synthetics and rubber parts may become inelastic, swell, shrink or crack, electric contacts may be oxydised, or isolations may lose their high electric resistance. Therefore, experts in the different components and their materials have collected and published not only plenty of observations, but also a number of more or less systematic approaches. A general picture, however, still seems to be lacking, due to the fact that ageing factors and mechanisms are not defined and used properly, i.e. - ageing factors act because of the service conditions of the components, as well as the characteristics of the materials which provoke ageing mechanisms - ageing mechanisms cause the changing of properties of the materials involved - combinations of single ageing mechanisms, which can be double, triple or multiple, change and accelerate the ageing process - the consequence of ageing mechanisms is the altering of the properties of the material depending on the lifetime. In this paper we shall try to show a systematic approach to a potential ageing analysis concerning the main metallic components of primary circuits of NPP's - connection between ageing factors, ageing mechanisms and their consequences/effects on component behaviour

  2. Bonding of Glass Ceramic and Indirect Composite to Non-aged and Aged Resin Composite

    NARCIS (Netherlands)

    Gresnigt, Marco; Ozcan, Mutlu; Muis, Maarten; Kalk, Warner

    2012-01-01

    Purpose: Since adhesion of the restorative materials to pre-polymerized or aged resin composites presents a challenge to the clinicians, existing restorations are often removed and remade prior to cementation of fixed dental prostheses (FDPs). This study evaluated bond strength of non-aged and aged

  3. Oral Health and Aging

    Science.gov (United States)

    ... please turn JavaScript on. Feature: Oral Health and Aging Oral Health and Aging Past Issues / Summer 2016 Table of Contents Jerrold ... they may need. Read More "Oral Health and Aging" Articles Oral Health and Aging / 4 Myths About ...

  4. The Newest Machine Material

    International Nuclear Information System (INIS)

    Seo, Yeong Seop; Choe, Byeong Do; Bang, Meong Sung

    2005-08-01

    This book gives descriptions of machine material with classification of machine material and selection of machine material, structure and connection of material, coagulation of metal and crystal structure, equilibrium diagram, properties of metal material, elasticity and plasticity, biopsy of metal, material test and nondestructive test. It also explains steel material such as heat treatment of steel, cast iron and cast steel, nonferrous metal materials, non metallic materials, and new materials.

  5. Gas storage materials, including hydrogen storage materials

    Science.gov (United States)

    Mohtadi, Rana F; Wicks, George G; Heung, Leung K; Nakamura, Kenji

    2013-02-19

    A material for the storage and release of gases comprises a plurality of hollow elements, each hollow element comprising a porous wall enclosing an interior cavity, the interior cavity including structures of a solid-state storage material. In particular examples, the storage material is a hydrogen storage material such as a solid state hydride. An improved method for forming such materials includes the solution diffusion of a storage material solution through a porous wall of a hollow element into an interior cavity.

  6. Modeling Creep Processes in Aging Polymers

    Science.gov (United States)

    Olali, N. V.; Voitovich, L. V.; Zazimko, N. N.; Malezhik, M. P.

    2016-03-01

    The photoelastic method is generalized to creep in hereditary aging materials. Optical-creep curves and mechanical-creep or optical-relaxation curves are used to interpret fringe patterns. For materials with constant Poisson's ratio, it is sufficient to use mechanical- or optical-creep curves for this purpose

  7. Age and osteoarthritis: are AGEs the link?

    NARCIS (Netherlands)

    Vos, P.A.J.M.

    2012-01-01

    Osteoarthritis is a common joint disease in the elderly. By far the most important risk factor for osteoarthritis is aging. Age-related changes in the articular cartilage may be responsible for age-related increase in the number of people with osteoarthritis. One of the most striking changes in

  8. Nondestructive Characterization of Aged Components

    Energy Technology Data Exchange (ETDEWEB)

    Panetta, Paul D.; Toloczko, Mychailo B.; Garner, Francis A.; Balachov, Iouri I.

    2003-10-21

    It is known that high energy radiation can have numerous effects on materials. In metals and alloys, the effects include, but may not be limited to, mechanical property changes, physical property changes, compositional changes, phase changes, and dimensional changes. Metals and alloys which undergo high energy self-irradiation are also susceptible to these changes. One of the greatest concerns with irradiation of materials is the phenomenon of void swelling which has been observed in a wide variety of metals and alloys. Irradiation causes the formation of a high concentration point defects and microclusters of vacancies and interstitials. With the assistance of an inert atom such as helium, the vacancy-type defects can coalesce to form a stable bubble. This bubble will continue to grow through the net absorption of more vacancy-type defects and helium atoms, and upon reaching a certain critical size, the bubble will begin to grow at an accelerated rate without the assistance of inert atom absorption. The bubble is then said to be an unstably growing void. Depending on the alloy system and environment, swelling values can reach in excess of 50% !V/Vo where Vo is the initial volume of the material. Along with dimensional changes resulting from the formation of bubbles and voids comes changes in the macroscopically observed speed of sound, moduli, electrical resistivity, yield strength, and other properties. These effects can be detrimental to the designed operation of the aged components. In situations where irradiation has sufficient time to cause degradation to materials used in critical applications such as nuclear reactor core structural materials, it is advisable to regularly survey the material properties. It is common practice to use surveillance specimens, but this is not always possible. When surveillance materials are not available, other means for surveying the material properties must be utilized. Sometimes it is possible to core out a small sample which

  9. Crystal chemistry of clinker relicts from aged cementitious materials

    Czech Academy of Sciences Publication Activity Database

    Secco, M.; Peruzzo, L.; Palasse, L.; Artioli, G.; Viani, Alberto; Gualtieri, A. F.

    2014-01-01

    Roč. 47, č. 5 (2014), s. 1626-1637 ISSN 0021-8898 R&D Projects: GA MŠk(CZ) LO1219 Keywords : aluminate * cement hydration * electron backscatter diffraction * electron microprobe analysis * ferrite Subject RIV: JN - Civil Engineering Impact factor: 3.720, year: 2014 http://scripts.iucr.org/cgi-bin/paper?S1600576714018287

  10. H1259 Container Foams: Performance Data on Aged Materials

    International Nuclear Information System (INIS)

    Linda Domeier

    2002-01-01

    Samples of the three cushioning foams used in the H1259 weapon storage container were obtained in 1997, 1998, 2000 and 2001 and tested for density, compression set and compressive strength using the same procedures specified for acceptance testing. Foams from six containers, all about 30 years old and located at Pantex, were evaluated. The bottom cushioning foam is a General Plastics polyurethane foam and the two side pads are rebonded polyurethane foams. All the tests were carried out at room temperature. When compared to the original acceptance requirements the foams were generally in-spec for density and compressive strength at 10% strain and were generally out-of-spec for compression set and compressive strength at 50% strain. Significant variability was noted in the performance of each foam sample and even more in the container-to-container foam performance. The container-to-container variability remains the major unknown in predicting the long-term suitability of these containers for continued use. The performance of the critical bottom cushion foams was generally more uniform and closer to the specified performance than that of the rebonded foams. It was judged that all the foams were adequate for continued use as storage container foams (not shipping) under controlled conditions to mitigate temperature extremes or high impact. This archived information is important in evaluations of the continued suitability for weapon storage use of the H1259 containers and other containers using the same foam cushions

  11. Management of ageing of motor operated isolating valve. Working material

    International Nuclear Information System (INIS)

    1994-01-01

    The objective of the Consultants' meeting held from 7 to 10 December 1993, Helsinki/Espoo, Finland was to prepare a background and implementation plan for the CRP. National reports on research topics were also presented. Refs, figs and tabs

  12. Structural aging program status report

    International Nuclear Information System (INIS)

    Naus, D.J.; Oland, C.B.; Ellingwood, B.; Graves, H.L. III

    1994-01-01

    Research is being conducted at the Oak Ridge National Laboratory under Nuclear Regulatory Commission (USNRC) sponsorship to address aging management of safety-related concrete structures. Documentation is being prepared to provide the USNRC with potential structural safety issues and acceptance criteria for use in continued service evaluations of nuclear power plants. Program accomplishments have included development of the Structural Materials Information Center containing data and information on the time variation of 144 material properties under the influence of pertinent environmental stressors or aging factors, performance assessments of reinforced concrete structures in several United Kingdom nuclear power facilities, evaluation of European and North American repair practices for concrete, an evaluation of factors affecting the corrosion of metals embedded in concrete, and application of the time-dependent reliability methodology to reinforced concrete flexure and shear structural elements to investigate the role of in-service inspection and repair on their probability of failure

  13. Towards Materials Sustainability through Materials Stewardship

    Directory of Open Access Journals (Sweden)

    Christopher D. Taylor

    2016-10-01

    Full Text Available Materials sustainability requires a concerted change in philosophy across the entire materials lifecycle, orienting around the theme of materials stewardship. In this paper, we address the opportunities for improved materials conservation through dematerialization, durability, design for second life, and diversion of waste streams through industrial symbiosis.

  14. Computational Materials Science | Materials Science | NREL

    Science.gov (United States)

    Computational Materials Science Computational Materials Science An image of interconnecting, sphere science capabilities span many research fields and interests. Electronic, Optical, and Transport Properties of Photovoltaic Materials Material properties and defect physics of Si, CdTe, III-V, CIGS, CZTS

  15. Methods for determination of the age of Pleistocene tephra, derived ...

    Indian Academy of Sciences (India)

    five of our samples has yielded material with an apparent age similar to that expected for eruption D. These numerical ages, of ..... about the history of uptake of radioactive elements ...... Approach to Management of Water and Soil of the Purna.

  16. Ageing management technical information investigations

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-08-15

    In February 2013, there are 50 units of commercial nuclear power plants (NPPs) in Japan. We enter into a period that 20 units of them are operating for more than 30 years. Currently, regulation imposes utilities to conduct ageing technical evaluations of each unit before operation of 30 years from the commissioning, to develop the long term maintenance management policy for next 10 years and to submit to the regulatory authority the policy with the report on ageing management technical evaluation (AMTE) for each NPP. It is necessary for regulatory side to develop technical information bases incorporating latest technical knowledge as operating experiences in domestic and abroad on ageing of the plants necessary to conduct reviews of AMTE for each unit. Based on these standpoints, technical information bases investigations have been conducted from the viewpoints of material degradation of ageing NPPs. In order to develop scientific regulator judgment bases related to ageing management (AM) and long-term operation (LTO), investigations on latest information on ageing management in domestic and abroad are conducted and a set of documents including technical evaluation review manuals necessary to conduct AMTE are prepared. To utilize the results of the investigations for ageing technical evaluation, database including latest information related to AM and LTO are developed, ran and operated. In addition, investigations related to Fugen nuclear plant, under decommissioning plants, investigations on mechanism of stress corrosion cracking (SCC), thermal ageing and preventive technologies for SCC, detection and diagnosis technology for ageing degradation and condition monitoring technology are performed to validate and confirm effectiveness of the technologies. (author)

  17. Shaping old age: Innovation partnerships, senior centres and billiards tables as active ageing technologies

    DEFF Research Database (Denmark)

    Lassen, Aske Juul

    2017-01-01

    During the past decade active ageing has been positioned as a solution to the problem of global ageing. While the scientific, economic and even moral arguments for pursuing a more active old age has been many, the integration of active ageing in everyday practices face challenges. This chapter...... explores the ways that active ageing policies become part of everyday practices, by proposing the concept of active ageing technologies. Active ageing technologies are material and immaterial condensations of knowledge that form old age in specific ways. Through the cases of an innovation partnership, two...... activity centres and a billiards table, the author explores how active ageing policies are transformed in practice. The chapter draws on an ethnographic study of active ageing conducted at the two activity centres, as well as the author’s participation in the innovation partnership. The author uses...

  18. Corrected Age for Preemies

    Science.gov (United States)

    ... Our Sponsors Ages & Stages Ages & Stages Ages and Stages Prenatal Baby (0-12 mos.) Toddler 1-3yrs. Preschool 3-5yrs Grade School 5-12yrs. Teen 12- ... the Word Shop AAP Find a Pediatrician Ages & Stages Prenatal Baby ... Gradeschool Teen Young Adult Healthy Children > Ages & Stages > ...

  19. The materials physics companion

    CERN Document Server

    Fischer-Cripps, Anthony C

    2014-01-01

    Introduction to Materials Physics: Structure of matter. Solid state physics. Dynamic properties of solids. Dielectric Properties of Materials: Dielectric properties. Ferroelectric and piezoelectric materials. Dielectric breakdown. Applications of dielectrics. Magnetic Properties of Materials: Magnetic properties. Magnetic moment. Spontaneous magnetization. Superconductivity.

  20. Nutrients, Microglia Aging, and Brain Aging

    Directory of Open Access Journals (Sweden)

    Zhou Wu

    2016-01-01

    Full Text Available As the life expectancy continues to increase, the cognitive decline associated with Alzheimer’s disease (AD becomes a big major issue in the world. After cellular activation upon systemic inflammation, microglia, the resident immune cells in the brain, start to release proinflammatory mediators to trigger neuroinflammation. We have found that chronic systemic inflammatory challenges induce differential age-dependent microglial responses, which are in line with the impairment of learning and memory, even in middle-aged animals. We thus raise the concept of “microglia aging.” This concept is based on the fact that microglia are the key contributor to the acceleration of cognitive decline, which is the major sign of brain aging. On the other hand, inflammation induces oxidative stress and DNA damage, which leads to the overproduction of reactive oxygen species by the numerous types of cells, including macrophages and microglia. Oxidative stress-damaged cells successively produce larger amounts of inflammatory mediators to promote microglia aging. Nutrients are necessary for maintaining general health, including the health of brain. The intake of antioxidant nutrients reduces both systemic inflammation and neuroinflammation and thus reduces cognitive decline during aging. We herein review our microglia aging concept and discuss systemic inflammation and microglia aging. We propose that a nutritional approach to controlling microglia aging will open a new window for healthy brain aging.

  1. Nutrients, Microglia Aging, and Brain Aging.

    Science.gov (United States)

    Wu, Zhou; Yu, Janchun; Zhu, Aiqin; Nakanishi, Hiroshi

    2016-01-01

    As the life expectancy continues to increase, the cognitive decline associated with Alzheimer's disease (AD) becomes a big major issue in the world. After cellular activation upon systemic inflammation, microglia, the resident immune cells in the brain, start to release proinflammatory mediators to trigger neuroinflammation. We have found that chronic systemic inflammatory challenges induce differential age-dependent microglial responses, which are in line with the impairment of learning and memory, even in middle-aged animals. We thus raise the concept of "microglia aging." This concept is based on the fact that microglia are the key contributor to the acceleration of cognitive decline, which is the major sign of brain aging. On the other hand, inflammation induces oxidative stress and DNA damage, which leads to the overproduction of reactive oxygen species by the numerous types of cells, including macrophages and microglia. Oxidative stress-damaged cells successively produce larger amounts of inflammatory mediators to promote microglia aging. Nutrients are necessary for maintaining general health, including the health of brain. The intake of antioxidant nutrients reduces both systemic inflammation and neuroinflammation and thus reduces cognitive decline during aging. We herein review our microglia aging concept and discuss systemic inflammation and microglia aging. We propose that a nutritional approach to controlling microglia aging will open a new window for healthy brain aging.

  2. Metallic composite materials

    International Nuclear Information System (INIS)

    Frommeyer, G.

    1987-01-01

    The structure and properties of metallic composite materials and composite materials with metallic matrix are considered. In agreement with the morphology of constituent phases the following types of composite materials are described: dispersion-strengthened composite materials; particle-reinforced composite materials; fibrous composite materials; laminar composite materials. Data on strength and electric properties of the above-mentioned materials, as well as effect of the amount, location and geometric shape of the second phase on them, are presented

  3. Fetal origin of vascular aging

    Directory of Open Access Journals (Sweden)

    Shailesh Pitale

    2011-01-01

    Full Text Available Aging is increasingly regarded as an independent risk factor for development of cardiovascular diseases such as atherosclerosis and hypertension and their complications (e.g. MI and Stroke. It is well known that vascular disease evolve over decades with progressive accumulation of cellular and extracellular materials and many inflammatory processes. Metabolic syndrome, obesity and diabetes are conventionally recognized as risk factors for development of coronary vascular disease (CVD. These conditions are known to accelerate ageing process in general and vascular ageing in particular. Adverse events during intrauterine life may programme organ growth and favour disease later in life, popularly known as, ′Barker′s Hypothesis′. The notion of fetal programming implies that during critical periods of prenatal growth, changes in the hormonal and nutritional milieu of the conceptus may alter the full expression of the fetal genome, leading to permanent effects on a range of physiological.

  4. Maternal age and child morbidity

    DEFF Research Database (Denmark)

    Hviid, Malene Meisner; Skovlund, Charlotte Wessel; Mørch, Lina Steinrud

    2017-01-01

    the association between maternal age and overall child morbidity according to main diagnosis groups. MATERIAL AND METHODS: We conducted a national cohort study including 352 027 live firstborn singleton children. The children were born between Jan 1994 and Dec 2009 and followed to Dec 2012. Children were divided...... into groups according to maternal age: 15-24, 25-29, 30-34, and 35+ years. Poisson regression analyses calculated adjusted incidence rate ratios (IRR) of child morbidities according to main diagnoses groups A-Q of the International Classification of Disease 10 with adjustment for year of birth, body mass...... index, smoking, and mother's level of education. RESULTS: Average follow-up time was 11 years. Compared to children born to women 25-29 years, firstborn children to mothers aged 35+ had higher child morbidity in 8 of 19 main diagnosis groups and firstborn children to mothers 15-24 years had higher child...

  5. PerformAge

    DEFF Research Database (Denmark)

    Fristrup, Tine

    2012-01-01

    are constituted as experts on aging. In the humanistic model of aging, the aging self becomes the expert on the process of becoming of age. Thi sconflicting aspect of the discursive battlefield on aging will be elaborated in the framework of PerformAge and understood as a temporal and spatial theorising of aging......: the poetics of aging. Making the lived experience the centrepiece of this paper, poetic representations of aging lives (Laurel Richardson, 1991, 1992) will articulate subjectively felt experiences in social encounters between people performing age. In writing the social (Dorothy E. Smith, 1999) encounters, I...... as a researcher perform age in the process of figuring the possible age performativities as subject positioning performativity (Judith Butler, 1995) in the social encounters and textualized in poetic representations. Inspired by the work on Reifungsromane (Barbara Frey Waxman, 1990), I do not want to paint...

  6. Composite material dosimeters

    Science.gov (United States)

    Miller, Steven D.

    1996-01-01

    The present invention is a composite material containing a mix of dosimeter material powder and a polymer powder wherein the polymer is transparent to the photon emission of the dosimeter material powder. By mixing dosimeter material powder with polymer powder, less dosimeter material is needed compared to a monolithic dosimeter material chip. Interrogation is done with excitation by visible light.

  7. Roofing Materials Assessment: Investigation of Five Metals in Runoff from Roofing Materials.

    Science.gov (United States)

    Winters, Nancy; Granuke, Kyle; McCall, Melissa

    2015-09-01

    To assess the contribution of five toxic metals from new roofing materials to stormwater, runoff was collected from 14 types of roofing materials and controls during 20 rain events and analyzed for metals. Many of the new roofing materials evaluated did not show elevated metals concentrations in the runoff. Runoff from several other roofing materials was significantly higher than the controls for arsenic, copper, and zinc. Notably, treated wood shakes released arsenic and copper, copper roofing released copper, PVC roofing released arsenic, and Zincalume® and EPDM roofing released zinc. For the runoff from some of the roofing materials, metals concentrations decreased significantly over an approximately one-year period of aging. Metals concentrations in runoff were demonstrated to depend on a number of factors, such as roofing materials, age of the materials, and climatic conditions. Thus, application of runoff concentrations from roofing materials to estimate basin-wide releases should be undertaken cautiously.

  8. Radiation and aging

    International Nuclear Information System (INIS)

    Kishikawa, Masao; Ikeyama, Mika; Iseki, Masachika; Shinkai, Kiyoto; Nishimori, Issei; Kondo, Hisayoshi; Fujii, Hideharu.

    1986-01-01

    Dorsal root ganglia (DRG) specimens were obtained from 3 women aged in their 6th decade and 5 men in their 8th decade, who were exposed to A-bomb at ≤ 3,000 m from the hypocenter in Nagasaki, and were analyzed for the frequency of DRG neurons with lipofuscin (LP), neuromelanin (NM), and eosinophilic granule (EG). The neurons for the men in the A-bomb group showed an increase of LP and a decrease of NM compared with those in age- and sex-matched control group, with significant differences (p < 0.05 and p < 0.01). The frequency of neurons with EG tended to be slightly higher for the men in the A-bomb group than in the control group; however, this was not statistically significant. For the women, there was a tendency toward a higher frequency of neurons with LP in the A-bomb group than in the control group, although no statistically significant difference emerged from this limited material. Regarding NM and EG for the women, DRG neurons showed no significant difference between the groups. Both men and women showed similar trends for the frequency of DRG neurons without pigments; no significant difference was observed between the groups. Regarding the sum of DRG neurons with large amounts of LP and with mixed LP and EG, the frequency of neurons was significantly higher for the men in the A-bomb group than in the control group, although this was not significant for the women. (Namekawa, K.)

  9. New concept of age(ing: Prospective age

    Directory of Open Access Journals (Sweden)

    Devedžić Mirjana

    2012-01-01

    Full Text Available While the last century was the century of world population growth, according to demographers, the XXI century will be century of population aging. Statistics undoubtedly show that number of elderly will continue it’s growth in the future. If old age is seen as period of life with reduced physical and mental capabilities and increased disability, and demographic aging as increase of dependent population, trends are quite disturbing, at least in certain societal segments. In developed countries, this population category is no longer treated as passive or as a "burden of society" and efforts are made for better social inclusion of older people. In contrast to growing interest in this phenomenon, the concepts that define the aging of the population remained stagnant. The aim of this paper is to introduce into domestic literature the term "prospective age" as a dynamic category which is more affected with socio-historical conditions, not only with biological as traditional definition of aging suggested. Papers written by Sanderson and Scherbov offer new methodological options for study of population aging, because it takes into account the biometric rather than chronological approach. Calculation of prospective years is a simple operation that requires pair of the same number of remained life expectancy from life tables for two different periods (the year of concern is index, and the one we are comparing with is standard year, so that phrase "40s is the new 30s" or "70s the new 60s" gets scientific foundation. Average remaining years of life represent a realistic indicator suggesting increased capacity, activity and vitality of individuals, which is due to accepted demographic parameters still considered old. „Prospective threshold“ is defined as the age when life expectancy falls below 15 years (it is subjective choice made by Sanderson and Scherbov, which is also used in this paper and during the elaboration of these ideas three demographic

  10. Method for forming materials

    Science.gov (United States)

    Tolle, Charles R [Idaho Falls, ID; Clark, Denis E [Idaho Falls, ID; Smartt, Herschel B [Idaho Falls, ID; Miller, Karen S [Idaho Falls, ID

    2009-10-06

    A material-forming tool and a method for forming a material are described including a shank portion; a shoulder portion that releasably engages the shank portion; a pin that releasably engages the shoulder portion, wherein the pin defines a passageway; and a source of a material coupled in material flowing relation relative to the pin and wherein the material-forming tool is utilized in methodology that includes providing a first material; providing a second material, and placing the second material into contact with the first material; and locally plastically deforming the first material with the material-forming tool so as mix the first material and second material together to form a resulting material having characteristics different from the respective first and second materials.

  11. Storage depot for radioactive material

    International Nuclear Information System (INIS)

    Szulinski, M.J.

    1983-01-01

    Vertical drilling of cylindrical holes in the soil, and the lining of such holes, provides storage vaults called caissons. A guarded depot is provided with a plurality of such caissons covered by shielded closures preventing radiation from penetrating through any linear gap to the atmosphere. The heat generated by the radioactive material is dissipated through the vertical liner of the well into the adjacent soil and thus to the ground surface so that most of the heat from the radioactive material is dissipated into the atmosphere in a manner involving no significant amount of biologically harmful radiation. The passive cooling of the radioactive material without reliance upon pumps, personnel, or other factor which might fail, constitutes one of the most advantageous features of this system. Moreover this system is resistant to damage from tornadoes or earthquakes. Hermetically sealed containers of radioactive material may be positioned in the caissons. Loading vehicles can travel throughout the depot to permit great flexibility of loading and unloading radioactive materials. Radioactive material can be shifted to a more closely spaced caisson after ageing sufficiently to generate much less heat. The quantity of material stored in a caisson is restricted by the average capacity for heat dissipation of the soil adjacent such caisson

  12. Photorefractive Materials and Their Applications 2 Materials

    CERN Document Server

    Günter, Peter

    2007-01-01

    Photorefractive Materials and Their Applications 2: Materials is the second of three volumes within the Springer Series in Optical Sciences. The book gives a comprehensive review of the most important photorefractive materials and discusses the physical properties of organic and inorganic crystals as well as poled polymers. In this volume, photorefractive effects have been investigated at wavelengths covering the UV, visible and near infrared. Researchers in the field and graduate students of solid-state physics and engineering will gain a thorough understanding of the properties of materials in photorefractive applications. The other two volumes are: Photorefractive Materials and Their Applications 1: Basic Effects. Photorefractive Materials and Their Applications 3: Applications.

  13. PENERAPAN MATERIAL KACA DALAM ARSITEKTUR

    Directory of Open Access Journals (Sweden)

    Lestari .

    2014-07-01

    Full Text Available Kaca telah dikenal sejak ribuan tahun dan merupakan bahan buatan manusia yang cukup tua. Penggunaannya sebagai bahan bangunan meluas sejak abad ke 17 terutama setelah perang dunia kedua.  Arsitektur kaca menjadi suatu kecenderungan dari desain-desain bangunan di dunia sejak abad ke-20. Material ini dianggap sangat relevan dengan konsep-konsep yang ada. Kaca digunakan sebagai material ornamen, bukaan atau jendela, material kulit  bangunan,  sampai pada material struktur  bangunan. Sifat kaca yang transparan,  simple, dan bersih menjadikan material ini menguntungkan untuk mendukung konsep yang digunakan. Tulisan ini memaparkan penggunaan kaca sebagai bahan bangunan, baik sebagai bahan ornamen, kulit bangunan atau struktur bangunan, maupun sebagai pendukung konsep arsitektur khususnya konsep transparansi. Dipaparkan pula mengenai sifat-sifat teknis dari bahan kaca sebagai pertimbangan dalam pemilihan bahan bangunan.   Glass has been known for thousands of years and is a man made material  that is quite old. Extends its use as building material since the 17 century, especially after the second world war. Glass architecture become a trend of buiding designs in the world since 20th century. This material relevant to the existing concepts. Glass is used as an ornament material, window, the building skin materials, and the building structure materials. Glass  properties that transparent, simple and clean make this material support the concepts used. This paper describes the use of glass as a building material, either as a ornament, the building skins, the building structures, and the building concepts expecially transparency concept. This paper also present the technical properties of glass as a building material REFERENCES Garg, N.K . 2007. Guidelines for Use of Glass in Building. New age international publisher. New Delhi Piano, R. 1997. The Renzo Piano Logbook. The Monacelli Press. London Staib, Schittich. 1999. Glass Construction

  14. Mechanical Material Engineering

    International Nuclear Information System (INIS)

    Kim, Mun Il

    1993-01-01

    This book introduced mechanical material with introduction, basic problems about metal ingredient of machine of metal and alloy, property of metal material mechanical metal material such as categorization of metal material and high tensile structure steel, mechanic design and steel material with three important points on using of steel materials, selection and directions machine structural steel, selection and directions of steel for tool, selection and instruction of special steel like stainless steel and spring steel, nonferrous metal materials and plastic.

  15. Monitoring ageing of components in nuclear plants

    International Nuclear Information System (INIS)

    Fritz, M.R.

    1992-01-01

    There are several mechanisms of ageing or damage in nuclear components, of which the best known can be classified into three categories: generalized damage mechanisms (wear, corrosion, erosion,...), local damage phenomena (fatigue, corrosion,...) and material property degradations. For ageing evaluation, the first requirement is a good understanding of the damage mechanisms and the determination of the kinetic laws and major influencing factors. When these factors are measurable physical parameters, ageing monitoring and periodic evaluation of damage level become possible. From the set of tools available for ageing evaluation, four are presented here in more detail: the transient logging procedure, the defect injuriousness analysis, the fatigue meter, the probabilistic approach to structural integrity. (author)

  16. Monitoring ageing of components in nuclear plants

    Energy Technology Data Exchange (ETDEWEB)

    Fritz, M R [FRAMATOME, Paris (France)

    1992-07-01

    There are several mechanisms of ageing or damage in nuclear components, of which the best known can be classified into three categories: generalized damage mechanisms (wear, corrosion, erosion,...), local damage phenomena (fatigue, corrosion,...) and material property degradations. For ageing evaluation, the first requirement is a good understanding of the damage mechanisms and the determination of the kinetic laws and major influencing factors. When these factors are measurable physical parameters, ageing monitoring and periodic evaluation of damage level become possible. From the set of tools available for ageing evaluation, four are presented here in more detail: the transient logging procedure, the defect injuriousness analysis, the fatigue meter, the probabilistic approach to structural integrity. (author)

  17. Hemostasis and ageing

    OpenAIRE

    Mari, D.; Ogliari, G.; Castaldi, D.; Vitale, G.; Bollini, E.M.; Lio, D.

    2008-01-01

    Abstract On March 19, 2008 a Symposium on Pathophysiology of Ageing and Age-Related Diseases was held in Palermo, Italy. The lecture of D. Mari on Hemostasis and ageing is summarized herein. Physiological ageing is associated with increased plasma levels of many proteins of blood coagulation together with fibrinolysis impairment. This may be of great concern in view of the known association between vascular and thromboembolic diseases and ageing. On the other hand, centenarians are characteri...

  18. Heart Age PSA (:60)

    Centers for Disease Control (CDC) Podcasts

    This 60 second public service announcement is based on the September 2015 CDC Vital Signs report. Your heart age is the age of your heart and blood vessels as a result of your risk factors for heart attack and stroke. If you smoke or have high blood pressure, your heart age will be much higher than your actual age. Learn what you can do to lower your heart age and keep it low.

  19. Filter-adsorber aging assessment

    Energy Technology Data Exchange (ETDEWEB)

    Winegardner, W.K. [Pacific Northwest Laboratory, Richland, WA (United States)

    1995-02-01

    An aging assessment of high-efficiency particulate (HEPA) air filters and activated carbon gas adsorption units was performed by the Pacific Northwest Laboratory as part of the U.S. Nuclear Regulatory Commission`s (USNRC) Nuclear Plant Aging Research (NPAR) Program. This evaluation of the general process in which characteristics of these two components gradually change with time or use included the compilation of information concerning failure experience, stressors, aging mechanisms and effects, and inspection, surveillance, and monitoring methods (ISMM). Stressors, the agents or stimuli that can produce aging degradation, include heat, radiation, volatile contaminants, and even normal concentrations of aerosol particles and gasses. In an experimental evaluation of degradation in terms of the tensile breaking strength of aged filter media specimens, over forty percent of the samples did not meet specifications for new material. Chemical and physical reactions can gradually embrittle sealants and gaskets as well as filter media. Mechanisms that can lead to impaired adsorber performance are associated with the loss of potentially available active sites as a result of the exposure of the carbon to airborne moisture or volatile organic compounds. Inspection, surveillance, and monitoring methods have been established to observe filter pressure drop buildup, check HEPA filters and adsorbers for bypass, and determine the retention effectiveness of aged carbon. These evaluations of installed filters do not reveal degradation in terms of reduced media strength but that under normal conditions aged media can continue to effectively retain particles. However, this degradation may be important when considering the likelihood of moisture, steam, and higher particle loadings during severe accidents and the fact it is probable that the filters have been in use for an extended period.

  20. Materials with structural hierarchy

    Science.gov (United States)

    Lakes, Roderic

    1993-01-01

    The role of structural hierarchy in determining bulk material properties is examined. Dense hierarchical materials are discussed, including composites and polycrystals, polymers, and biological materials. Hierarchical cellular materials are considered, including cellular solids and the prediction of strength and stiffness in hierarchical cellular materials.

  1. Coated electroactive materials

    Science.gov (United States)

    Amine, Khalil; Abouimrane, Ali

    2016-08-30

    A process includes suspending an electroactive material in a solvent, suspending or dissolving a carbon precursor in the solvent; and depositing the carbon precursor on the electroactive material to form a carbon-coated electroactive material. Compositions include a graphene-coated electroactive material prepared from a solution phase mixture or suspension of an electroactive material and graphene, graphene oxide, or a mixture thereof.

  2. Aerogel / Polymer Composite Materials

    Science.gov (United States)

    Williams, Martha K. (Inventor); Smith, Trent M. (Inventor); Fesmire, James E. (Inventor); Roberson, Luke B. (Inventor); Clayton, LaNetra M. (Inventor)

    2017-01-01

    The invention provides new composite materials containing aerogels blended with thermoplastic polymer materials at a weight ratio of aerogel to thermoplastic polymer of less than 20:100. The composite materials have improved thermal insulation ability. The composite materials also have better flexibility and less brittleness at low temperatures than the parent thermoplastic polymer materials.

  3. Nanocrystalline ceramic materials

    Science.gov (United States)

    Siegel, Richard W.; Nieman, G. William; Weertman, Julia R.

    1994-01-01

    A method for preparing a treated nanocrystalline metallic material. The method of preparation includes providing a starting nanocrystalline metallic material with a grain size less than about 35 nm, compacting the starting nanocrystalline metallic material in an inert atmosphere and annealing the compacted metallic material at a temperature less than about one-half the melting point of the metallic material.

  4. Materials Informatics: Statistical Modeling in Material Science.

    Science.gov (United States)

    Yosipof, Abraham; Shimanovich, Klimentiy; Senderowitz, Hanoch

    2016-12-01

    Material informatics is engaged with the application of informatic principles to materials science in order to assist in the discovery and development of new materials. Central to the field is the application of data mining techniques and in particular machine learning approaches, often referred to as Quantitative Structure Activity Relationship (QSAR) modeling, to derive predictive models for a variety of materials-related "activities". Such models can accelerate the development of new materials with favorable properties and provide insight into the factors governing these properties. Here we provide a comparison between medicinal chemistry/drug design and materials-related QSAR modeling and highlight the importance of developing new, materials-specific descriptors. We survey some of the most recent QSAR models developed in materials science with focus on energetic materials and on solar cells. Finally we present new examples of material-informatic analyses of solar cells libraries produced from metal oxides using combinatorial material synthesis. Different analyses lead to interesting physical insights as well as to the design of new cells with potentially improved photovoltaic parameters. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Materials for the 21st century

    CERN Document Server

    Segal, David

    2017-01-01

    The book is a general text that shows how materials can contribute to solving problems facing nations in the 21st century. It is illustrated with diverse applications and highlights the potential of existing materials for everyday life, healthcare and the economies of nations. There are 13 chapters and a glossary of 500 materials with their descriptions, historical development, their use or potential use and a range of references. Specific areas include synthetic polymers (e.g. nylon), natural polymers (e.g. proteins, cellulose) and the role of materials in the development of digital computers and in healthcare. Solid-state lighting, energy supplies in the 21st century, disruptive technologies and intellectual property, in particular patents, are discussed. The book concludes by asking how the 21st century will be characterised. Will it be the Silicon Age, Genomic Age or New Polymer Age, as examples?

  6. Material efficiency: providing material services with less material production.

    Science.gov (United States)

    Allwood, Julian M; Ashby, Michael F; Gutowski, Timothy G; Worrell, Ernst

    2013-03-13

    Material efficiency, as discussed in this Meeting Issue, entails the pursuit of the technical strategies, business models, consumer preferences and policy instruments that would lead to a substantial reduction in the production of high-volume energy-intensive materials required to deliver human well-being. This paper, which introduces a Discussion Meeting Issue on the topic of material efficiency, aims to give an overview of current thinking on the topic, spanning environmental, engineering, economics, sociology and policy issues. The motivations for material efficiency include reducing energy demand, reducing the emissions and other environmental impacts of industry, and increasing national resource security. There are many technical strategies that might bring it about, and these could mainly be implemented today if preferred by customers or producers. However, current economic structures favour the substitution of material for labour, and consumer preferences for material consumption appear to continue even beyond the point at which increased consumption provides any increase in well-being. Therefore, policy will be required to stimulate material efficiency. A theoretically ideal policy measure, such as a carbon price, would internalize the externality of emissions associated with material production, and thus motivate change directly. However, implementation of such a measure has proved elusive, and instead the adjustment of existing government purchasing policies or existing regulations-- for instance to do with building design, planning or vehicle standards--is likely to have a more immediate effect.

  7. The Aging Epigenome

    Science.gov (United States)

    Booth, Lauren N.

    2016-01-01

    During aging, the mechanisms that normally maintain health and stress resistance strikingly decline, resulting in decrepitude, frailty, and ultimately death. Exactly when and how this decline occurs is unknown. Changes in transcriptional networks and chromatin state lie at the heart of age-dependent decline. These epigenomic changes are not only observed during aging but also profoundly affect cellular function and stress resistance, thereby contributing to the progression of aging. We propose that the dysregulation of transcriptional and chromatin networks is a crucial component of aging. Understanding age-dependent epigenomic changes will yield key insights into how aging begins and progresses and should lead to the development of new therapeutics that delay or even reverse aging and age-related diseases. PMID:27259204

  8. Aromatherapy Oils: Commodities, Materials, Essences

    Directory of Open Access Journals (Sweden)

    Ruth Barcan

    2014-08-01

    Full Text Available This article examines the essential oils that are the central tools of aromatherapy and uses them as a case study for different approaches to material culture. It considers the conceptual and political implications of thinking of essential oils as, in turn, commodities, materials and essences. I argue that both cultural studies and aromatherapy have something to learn from each other. Classic materialist approaches might do well to focus more attention on the material properties and effects of things. Aromatherapy, on the other hand, could benefit from the enriched political understanding associated with classic materialist critique. New materialist strains of cultural studies may also find the vibrancy of matter that underpins many CAM/New Age practices worthy of examination.

  9. Epigenetic predictor of age.

    Directory of Open Access Journals (Sweden)

    Sven Bocklandt

    Full Text Available From the moment of conception, we begin to age. A decay of cellular structures, gene regulation, and DNA sequence ages cells and organisms. DNA methylation patterns change with increasing age and contribute to age related disease. Here we identify 88 sites in or near 80 genes for which the degree of cytosine methylation is significantly correlated with age in saliva of 34 male identical twin pairs between 21 and 55 years of age. Furthermore, we validated sites in the promoters of three genes and replicated our results in a general population sample of 31 males and 29 females between 18 and 70 years of age. The methylation of three sites--in the promoters of the EDARADD, TOM1L1, and NPTX2 genes--is linear with age over a range of five decades. Using just two cytosines from these loci, we built a regression model that explained 73% of the variance in age, and is able to predict the age of an individual with an average accuracy of 5.2 years. In forensic science, such a model could estimate the age of a person, based on a biological sample alone. Furthermore, a measurement of relevant sites in the genome could be a tool in routine medical screening to predict the risk of age-related diseases and to tailor interventions based on the epigenetic bio-age instead of the chronological age.

  10. Conducting Polymeric Materials

    DEFF Research Database (Denmark)

    Hvilsted, Søren

    2016-01-01

    The overall objective of this collection is to provide the most recent developments within the various areas of conducting polymeric materials. The conductivity of polymeric materials is caused by electrically charged particles, ions, protons and electrons. Materials in which electrons...

  11. Transitional Thermal Creep of Early Age Concrete

    DEFF Research Database (Denmark)

    Hauggaard-Nielsen, Anders Boe; Damkilde, Lars; Freiesleben Hansen, Per

    1999-01-01

    Couplings between creep of hardened concrete and temperature/water effects are well-known. Both the level and the gradients in time of temperature or water content influence the creep properties. In early age concrete the internal drying and the heat development due to hydration increase the effect...... of these couplings. The purpose of this work is to set up a mathematical model for creep of concrete which includes the transitional thermal effect. The model govern both early age concrete and hardened concrete. The development of the material properties in the model are assumed to depend on the hydration process...... termed the microprestresses, which reduces the stiffness of the concrete and increase the creep rate. The aging material is modelled in an incremental way reflecting the hydration process in which new layers of cement gel solidifies in a stress free state and add stiffness to the material. Analysis...

  12. Aging in culture.

    Science.gov (United States)

    Fung, Helene H

    2013-06-01

    This article reviews the empirical studies that test socioemotional aging across cultures. The review focuses on comparisons between Western (mostly North Americans and Germans) and Eastern cultures (mostly Chinese) in areas including age-related personality, social relationships, and cognition. Based on the review, I argue that aging is a meaning-making process. Individuals from each cultural context internalize cultural values with age. These internalized cultural values become goals that guide adult development. When individuals from different cultures each pursue their own goals with age, cultural differences in socioemotional aging occur.

  13. Aging of gaseous detectors

    International Nuclear Information System (INIS)

    Va'Vra, J.

    1990-03-01

    This paper makes an overview of developments in the wire chamber aging field since the wire chamber aging workshop held at the Lawrence Berkeley Laboratory, Berkeley, California on January 16--17, 1986. The author discusses new techniques to analyze the gas impurities and the wire aging products, wire ''nonaging'' in clean systems, wire aging in systems containing various impurities, various examples of problems which can ''prime'' surfaces prior to the occurrence of the aging, and some recent aging experience with the ''SSC micro-straw tubes.'' 35 refs., 10 figs., 2 tabs

  14. Multifunctional materials and composites

    Science.gov (United States)

    Seo, Dong-Kyun; Jeon, Ki-Wan

    2017-08-22

    Forming multifunctional materials and composites thereof includes contacting a first material having a plurality of oxygen-containing functional groups with a chalcogenide compound, and initiating a chemical reaction between the first material and the chalcogenide compound, thereby replacing oxygen in some of the oxygen-containing functional groups with chalcogen from the chalcogen-containing compound to yield a second material having chalcogen-containing functional groups and oxygen-containing functional groups. The first material is a carbonaceous material or a macromolecular material. A product including the second material is collected and may be processed further to yield a modified product or a composite.

  15. Sea materials experimental plans

    International Nuclear Information System (INIS)

    1987-07-01

    This Seal Materials Performance Test Plan describes the plan for testing materials that will be used to seal a high-level nuclear waste repository in salt at a proposed site in Deaf Smith County, Texas. The need for sealing and backfilling the repository and the use of various sealing materials are described. The seal materials include mined salt backfills, cementitious bulkheads and plugs, and earthen backfills. The laboratory testing program for characterizing the behavior and performance of these materials is described. This report includes plans for screening materials, evaluating candidate materials to be tested, and testing a representative set of materials

  16. Nanoscale materials in chemistry

    National Research Council Canada - National Science Library

    Klabunde, Kenneth J; Richards, Ryan

    2009-01-01

    ...: Disordered, Porous Nanostructures Stephanie L. Brock 209 9 Ordered Microporous and Mesoporous Materials Freddy Kleitz 243 10 Applications of Microporous and Mesoporous Materials Anirban Ghosh,...

  17. Overview of synergistic aging effects

    International Nuclear Information System (INIS)

    Steigelmann, W.; Farber, M.

    1982-01-01

    Proper, technically defensible qualification of materials and equipment for nuclear power facilities requires that the effects of combined environment exposures be addressed. The full significance of synergistic effects resulting from combined stresses still remains largely an unknown to be provided for by use of conservatisms, allowing a sizeable margin in test programs and analyses to account for possible combined effects. However, these margins, when applied to sequential aging tests, may under- or over-estimate the qualified life of the material or equipment. Experimentation with radiation dose-rate effects, simultaneous vs. sequential ordered exposures, and other combined environment testing are highlighted in this paper to provide an overview of the current state-of-knowledge concerning synergistic effects and their significance to qualification programs

  18. Charasteristics of Ageing Population in Semarang City

    Directory of Open Access Journals (Sweden)

    Puji Hardati

    2016-12-01

    Full Text Available Increase of amount of ageing population represent the indication that a region have experienced of the ageing population. In some developing countries, of including Indonesia, growth of ageing population are estimate will mount quickly in period to come, although its percentage do not same. Whereas characteristic do not know surely. This matter is caused by there is view that ageing population of still not yet of this problem, but within long term will be are problem of if are not paid attention since now. Studying of ageing population of pursuant to its characteristic will assist in handling good problems now and also to come. With the existence of data of usable ageing population resident characteristic for the materials of population development planning in area.

  19. Aging and Health: Cataracts

    Science.gov (United States)

    ... Problems Glaucoma Macular Degeneration Join our e-newsletter! Aging & Health A to Z Cataracts Basic Facts & Information ... Are Cataracts? Cataracts are a common result of aging and occur frequently in older people. About one ...

  20. Aging changes in immunity

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/004008.htm Aging changes in immunity To use the sharing features ... cells and antibodies that destroy these harmful substances. AGING CHANGES AND THEIR EFFECTS ON THE IMMUNE SYSTEM ...

  1. National Council on Aging

    Science.gov (United States)

    ... Centers Center for Benefits Access Center for Healthy Aging Donate Skip to Content a A Menu Economic ... Seniors Home Equity Older Workers Money Management Healthy Aging Falls Prevention Chronic Disease Management Senior Hunger & Nutrition ...

  2. NIA Aging Cell Repository

    Data.gov (United States)

    Federal Laboratory Consortium — To facilitate aging research on cells in culture, the NIA provides support for the NIA Aging Cell Repository, located at the Coriell Institute for Medical Research...

  3. Memory and Aging

    Science.gov (United States)

    Memory and Aging Losing keys, misplacing a wallet, or forgetting someone’s name are common experiences. But for people nearing or over age 65, such memory lapses can be frightening. They wonder if they ...

  4. Physically Functional Materials

    DEFF Research Database (Denmark)

    2002-01-01

    acids or peptides having azobenzenes or other physicially functional groups, e.g., photoresponsive groups, as side chains. These compounds may be synthesized using solid phase peptide synthesis techniques. Materials, e.g., thin films, comprising such compounds may be used for optical storage...... of information (holographic data storage), nonlinear optics (NLO), as photoconductors, photonic band-gap materials, electrically conducting materials, electroluminescent materials, piezo-electric materials, pyroelectric materials, magnetic materials, ferromagnetic materials, ferroelectric materials......, photorefractive materials, or materials in which light-induced conformational changes can be produced. Optical anisotropy may reversibly be generated with polarized laser light whereby a hologram is formed. First order diffraction efficiencies of up to around 80% have been obtained....

  5. Kevlar 49/Epoxy COPV Aging Evaluation

    Science.gov (United States)

    Sutter, James K.; Salem, Jonathan L.; Thesken, John C.; Russell, Richard W.; Littell, Justin; Ruggeri, Charles; Leifeste, Mark R.

    2008-01-01

    NASA initiated an effort to determine if the aging of Kevlar 49/Epoxy composite overwrapped pressure vessels (COPV) affected their performance. This study briefly reviews the history and certification of composite pressure vessels employed on NASA Orbiters. Tests to evaluate overwrap tensile strength changes compared 30 year old samples from Orbiter vessels to new Kevlar/Epoxy pressure vessel materials. Other tests include transverse compression and thermal analyses (glass transition and moduli). Results from these tests do not indicate a noticeable effect due to aging of the overwrap materials.

  6. The Global Age NGIOA @ Risk

    CERN Document Server

    Pandya, Jayshree

    2012-01-01

    Dr. Jayshree Pandya, founder of Risk Group LLC, is ahead of the curve in addressing the changing global fundamentals of the emerging Global Age.   The Global Age, and its changing global fundamentals has brought complex, chaotic, and turbulent times for every nation—where failures on all levels have become self-evident, repetitive, destructive, and potentially hopeless in nature and uncertainty. Nations are caught off guard.   From what is visible worldwide today, the promise of progress and prosperity for all nations does not seem to have materialized in this Global Age. Instead of progress and prosperity, we see crisis and catastrophe  overpowering and overwhelming the capability of most nations to meet their promise of progress and prosperity. Nations are in crisis. This introductory book addresses the global shifts and the changing global fundamentals of the Global Age, to lay out a much needed foundation of an integrated NGIOA risk governance framework for the near future. This book will make a conv...

  7. Osteoarticular system aging

    Directory of Open Access Journals (Sweden)

    Edison Rossi

    2008-03-01

    Full Text Available The dichotomy of “natural-aging” versus “disease-aging” in fact doesnot exist. The author discusses the pathophysiology of osteoarticularsystem aging to show facts of bone aging, mainly changings ofarticular cartilage and skeletal muscle tissue aged-related. He stilldiscusses about the skeletal muscle mass defi ciency (sarcopenia inthe frontier of aging (senescence and disease (senility as well asits role in disability and functional dependence that are associated to frailty in many elderly people.

  8. Osteoclasts prefer aged bone

    DEFF Research Database (Denmark)

    Henriksen, K; Leeming, Diana Julie; Byrjalsen, I

    2007-01-01

    We investigated whether the age of the bones endogenously exerts control over the bone resorption ability of the osteoclasts, and found that osteoclasts preferentially develop and resorb bone on aged bone. These findings indicate that the bone matrix itself plays a role in targeted remodeling...... of aged bones....

  9. Physiological Aging and Exercise.

    Science.gov (United States)

    Osness, Wayne

    This paper explores the nature of the aging process by providing an overview of the available evidence relating to the body systems that are most critical to biological function. Each system is treated separately to more clearly describe various aspects of the aging process and then integrated in a discussion of the theories of biological aging.…

  10. Optimal Aging and Death

    DEFF Research Database (Denmark)

    Dalgaard, Carl-Johan Lars; Strulik, Holger

    2010-01-01

    This study introduces physiological aging into a simple model of optimal intertemporal consumption. In this endeavor we draw on the natural science literature on aging. According to the purposed theory, the speed of the aging process and the time of death are endogenously determined by optimal...

  11. Optimal Aging and Death

    DEFF Research Database (Denmark)

    Dalgaard, Carl-Johan; Strulik, Holger

    the representative consumer is subject to physiological aging. In modeling aging we draw on recent research in the fields of biology and medicine. The speed of the aging process, and thus the time of death, are endogenously determined by optimal health investments. We calibrate the model to US data and proceed...

  12. Language and Aging.

    Science.gov (United States)

    Kemper, Susan; Anagnopoulos, Cheryl

    1989-01-01

    Reviews the effects of aging on language usage focusing on three areas of exploration: (1) changes in language in relation to changes in other cognitive abilities, (2) the linguistic consequences of normal aging versus those of dementia and aphasia, and (3) age-group differences in patterns of conversational interaction. (67 references) (GLR)

  13. Age of the universe

    International Nuclear Information System (INIS)

    Parker, B.

    1981-01-01

    The age of the universe is the time that has elapsed since the Big Bang. To calculate the age, the expansion rate of the universe and distance to the galaxies must be determined. Unfortunately, it appears that the expansion rate is not constant but is decelerating. In the 1920's and 30's, Edwin Hubble set out to estimate the age of universe based on the expansion rate and distance to the galaxies. His method is described along with its flaw. Since that time several others have estimated the age of the universe. Their methods as well as results vary. These are discussed in the article. The ages determined from the various methods range from 10 to 20 billion years. There are two independent ways to determine the age of the universe. What they actually do is determine the age of our galaxy which would give a lower limit to the age of the universe. The first method calculates age of globular clusters which yields as age range from 8 to 18 billion years. The second method involves observing the speed at which radioactive substances decay. This also yields and age greater than 10 billion years. It is clear that there is still a lot of work to do before the true age of the universe can be determied

  14. New age constraints on the Middle Stone Age occupations of Kharga Oasis, Western Desert, Egypt.

    Science.gov (United States)

    Smith, Jennifer R; Hawkins, Alicia L; Asmerom, Yemane; Polyak, Victor; Giegengack, Robert

    2007-06-01

    Spring-deposited carbonate rocks, or tufas, exposed along the flanks of the Libyan Plateau near Kharga Oasis, Western Desert, Egypt, can provide a directly datable stratigraphic context for Middle Stone Age/Middle Paleolithic (MSA/MP) archaeological material, if such material can be found in situ within tufa strata. Two such localities (Mata'na Site G and Bulaq Wadi 3 Locus 1) described by Caton-Thompson were revisited and sampled for uranium-series analysis. At Mata'na Site G (KH/MT-02), Middle Stone Age ("Upper Levalloisian") material is underlain by tufa with a uranium-series age of 127.9+/-1.3 ka, and overlain by tufa with an age of 103+/-14 ka. At Bulaq Wadi 3 Locus 1, a uranium-series age of 114.4+/-4.2 ka on tufa capping a small collection of Middle Stone Age artifacts also provides a minimum age constraint on that material. Tufa underlying an MSA workshop (KH/MD-10) indicates that this assemblage, characterized by use of several Levallois reduction methods, was deposited after approximately 124 ka. Furthermore, uranium-series ages averaging approximately 133 ka on a Wadi Midauwara tufa (WME-10) without associated archaeological material suggest that one period of spring flow in the region began during the Marine Isotope Stage 6/5e transition, prior to the warmest portion of the last interglacial period. The dated archaeological material suggests that the distinction that has been identified between Nubian and non-Nubian complexes in the Nile Valley may hold for the Western Desert, although local complexity has yet to be fully described.

  15. Tritium breeding materials

    International Nuclear Information System (INIS)

    Hollenberg, G.W.; Johnson, C.E.; Abdou, M.

    1984-03-01

    Tritium breeding materials are essential to the operation of D-T fusion facilities. Both of the present options - solid ceramic breeding materials and liquid metal materials are reviewed with emphasis not only on their attractive features but also on critical materials issues which must be resolved

  16. Tritium breeding materials

    International Nuclear Information System (INIS)

    Hollenberg, G.W.; Johnson, C.E.; Abdou, M.A.

    1984-01-01

    Tritium breeding materials are essential to the operation of D-T fusion facilities. Both of the present options - solid ceramic breeding materials and liquid metal materials are reviewed with emphasis not only on their attractive features but also on critical materials issues which must be resolved

  17. Materials Science | NREL

    Science.gov (United States)

    microscopy and imaging science, interfacial and surface science, materials discovery, and thin-film material Science Materials Science Illustration with bottom row showing a ball-and-stick model and top row dense black band. State-of-the-art advances in materials science come from a combination of experiments

  18. Coated ceramic breeder materials

    Science.gov (United States)

    Tam, Shiu-Wing; Johnson, Carl E.

    1987-01-01

    A breeder material for use in a breeder blanket of a nuclear reactor is disclosed. The breeder material comprises a core material of lithium containing ceramic particles which has been coated with a neutron multiplier such as Be or BeO, which coating has a higher thermal conductivity than the core material.

  19. Method for accelerated aging under combined environmental stress conditions

    International Nuclear Information System (INIS)

    Gillen, K.T.

    1979-01-01

    An accelerated aging method which can be used to simulate aging in combined stress environment situations is described. It is shown how the assumptions of the method can be tested experimentally. Aging data for a chloroprene cable jacketing material in single and combined radiation and temperature environments are analyzed and it is shown that these data offer evidence for the validity of the method

  20. Heart Age PSA (:60)

    Centers for Disease Control (CDC) Podcasts

    2015-09-01

    This 60 second public service announcement is based on the September 2015 CDC Vital Signs report. Your heart age is the age of your heart and blood vessels as a result of your risk factors for heart attack and stroke. If you smoke or have high blood pressure, your heart age will be much higher than your actual age. Learn what you can do to lower your heart age and keep it low.  Created: 9/1/2015 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 9/1/2015.

  1. Computational biology for ageing

    Science.gov (United States)

    Wieser, Daniela; Papatheodorou, Irene; Ziehm, Matthias; Thornton, Janet M.

    2011-01-01

    High-throughput genomic and proteomic technologies have generated a wealth of publicly available data on ageing. Easy access to these data, and their computational analysis, is of great importance in order to pinpoint the causes and effects of ageing. Here, we provide a description of the existing databases and computational tools on ageing that are available for researchers. We also describe the computational approaches to data interpretation in the field of ageing including gene expression, comparative and pathway analyses, and highlight the challenges for future developments. We review recent biological insights gained from applying bioinformatics methods to analyse and interpret ageing data in different organisms, tissues and conditions. PMID:21115530

  2. Aging, longevity and health

    DEFF Research Database (Denmark)

    Rasmussen, Lene Juel; Sander, Miriam; Wewer, Ulla M.

    2011-01-01

    The IARU Congress on Aging, Longevity and Health, held on 5-7 October 2010 in Copenhagen, Denmark, was hosted by Rector Ralf Hemmingsen, University of Copenhagen and Dean Ulla Wewer, Faculty of Health Sciences, University of Copenhagen and was organized by Center for Healthy Aging (CEHA) under......, Muscle and Life Span and Life Span and Mechanisms. Two additional Sessions highlighted ongoing research in the recently established Center for Healthy Aging at the University of Copenhagen. This report highlights outcomes of recent research on aging-related topics, as described at the IARU Congress...... on Aging, Longevity and Health....

  3. Aging and Vision.

    Science.gov (United States)

    Alavi, Marcel V

    2016-01-01

    Aging involves defined genetic, biochemical and cellular pathways that regulate lifespan. These pathways are called longevity pathways and they have relevance for many age-related diseases. In the eye, longevity pathways are involved in the major blinding diseases, cataract, glaucoma, age-related macular degeneration (AMD) and diabetic retinopathy. Pharmaceutical targeting of longevity pathways can extend healthy lifespan in laboratory model systems. This offers the possibility of therapeutic interventions to also delay onset or slow the progression of age-related eye diseases. I suggest that retinal degeneration may be viewed as accelerated aging of photoreceptors and that interventions extending healthy lifespan may also slow the pace of photoreceptor loss.

  4. Ageing Management of CARR

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, H., E-mail: Carr200404@hotmail.com [China Institute of Atomic Energy (CIAE), Beijing (China)

    2014-08-15

    The paper introduced the ageing management of CARR, including the ageing management system, instances of ageing components, difficulties we met and follow up plan, and put forward some suggestions on strengthening and promoting ageing management. We hope to enhance international exchange and collaboration. It is a great challenge to do research on how to manage ageing effectively in the beginning of life, but it will enhance the safety of reactor operation, extend the life of the reactor and improve the quality of operation, making this work very meaningful.

  5. Smoking, health and ageing

    Directory of Open Access Journals (Sweden)

    Nicita-Mauro Claudio

    2008-09-01

    Full Text Available Abstract On March 19, 2008 a Symposium on Pathophysiology of Ageing and Age-Related diseases was held in Palermo, Italy. Here, the lecture of V. Nicita-Mauro on Smoking, health and ageing is summarized. Smoking represents an important ageing accelerator, both directly by triggering an inflammatory responses, and indirectly by favoring the occurrence of several diseases where smoking is a recognized risk factor. Hence, non-smokers can delay the appearance of diseases and of ageing process, so attaining longevity.

  6. Development of the structural materials information center

    International Nuclear Information System (INIS)

    Oland, C.B.; Naus, D.J.

    1990-01-01

    The U.S. Nuclear Regulatory Commission has initiated a Structural Aging Program at the Oak Ridge National Laboratory to identify potential structural safety issues related to continued service of nuclear power plants and to establish criteria for evaluating and resolving these issues. One of the tasks in this program focuses on the establishment of a Structural Materials Information Center where data and information on the time variation of concrete and other structural material properties under the influence of pertinent environmental stressors and aging factors are being collected and assembled into a database. This database will be used to assist in the prediction of potential long-term deterioration of critical structural components in nuclear power plants and to establish limits on hostile environmental exposure for these structures and materials. Two complementary database formats have been developed. The Structural Materials Handbook is an expandable, hard copy handbook that contains complete sets of data and information for selected portland cement concrete, metallic reinforcement, prestressing tendon, and structural steel materials. The Structural Materials Electronic Database is accessible by an IBM-compatible personal computer and provides an efficient means for searching the various database files to locate materials with similar properties. The database formats have been developed to accommodate data and information on the time-variation of concrete and other structural material properties. To date, the database includes information on concrete, reinforcement, prestressing, and structural steel materials

  7. Materials Analysis and Modeling of Underfill Materials.

    Energy Technology Data Exchange (ETDEWEB)

    Wyatt, Nicholas B [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Chambers, Robert S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-08-01

    The thermal-mechanical properties of three potential underfill candidate materials for PBGA applications are characterized and reported. Two of the materials are a formulations developed at Sandia for underfill applications while the third is a commercial product that utilizes a snap-cure chemistry to drastically reduce cure time. Viscoelastic models were calibrated and fit using the property data collected for one of the Sandia formulated materials. Along with the thermal-mechanical analyses performed, a series of simple bi-material strip tests were conducted to comparatively analyze the relative effects of cure and thermal shrinkage amongst the materials under consideration. Finally, current knowledge gaps as well as questions arising from the present study are identified and a path forward presented.

  8. Queering Aging Futures

    Directory of Open Access Journals (Sweden)

    Linn J. Sandberg

    2017-08-01

    Full Text Available This paper explores the potential for cultural gerontology to extend its ideas of diversity in aging experiences by opening space to rethink conceptions of successful aging futures. We propose a ‘queering’ of aging futures that disrupts the ways that expectations of a good later life and happy aging are seen to adhere to some bodies and subjectivities over others. Drawing on feminist, queer, and crip theories, we build on existing critiques of ‘successful aging’ to interrogate the assumptions of heteronormativity, able-bodiedness and able-mindedness that shape the dividing lines between success and failure in aging, and which inform attempts to ‘repair’ damaged futures. Conclusions suggest that recognizing diversity in successful aging futures is important in shaping responses to the challenges of aging societies, and presents an opportunity for critical cultural gerontology to join with its theoretical allies in imagining more inclusive alternatives.

  9. Aging and sexuality.

    Science.gov (United States)

    Yee, Lesley

    2010-10-01

    Sexuality has become a medical issue in association with aging. This is due to a number of factors, including increasing age of survival, a positive societal construct that promotes sexuality as important for quality of life as we age, and the medicalisation of sexuality with the advent of prescription medications to treat sexual dysfunction. This article reviews the factors surrounding aging and sexuality and also considers special situations with age, such as institutionalised care and the possibility of elder abuse. Normal physiological changes with aging affect both genders in terms of sexual desire and performance. Other medical conditions increase with age, and these and their treatments will impact on sexuality and the way it can be expressed. Medical practitioners require an understanding of these changes in order to find ways to optimise sexual function in older patients.

  10. Can aging be programmed?

    DEFF Research Database (Denmark)

    Kowald, Axel; Kirkwood, Thomas B. L.

    2016-01-01

    The evolution of the aging process has long been a biological riddle, because it is difficult to explain the evolution of a trait that has apparently no benefit to the individual. Over 60 years ago, Medawar realized that the force of natural selection declines with chronological age because...... of unavoidable environmental risks. This forms the basis of the mainstream view that aging arises as a consequence of a declining selection pressure to maintain the physiological functioning of living beings forever. Over recent years, however, a number of articles have appeared that nevertheless propose...... the existence of specific aging genes; that is, that the aging process is genetically programmed. If this view were correct, it would have serious implications for experiments to understand and postpone aging. Therefore, we studied in detail various specific proposals why aging should be programmed. We find...

  11. The Hallmarks of Aging

    Science.gov (United States)

    López-Otín, Carlos; Blasco, Maria A.; Partridge, Linda; Serrano, Manuel; Kroemer, Guido

    2013-01-01

    Aging is characterized by a progressive loss of physiological integrity, leading to impaired function and increased vulnerability to death. This deterioration is the primary risk factor for major human pathologies including cancer, diabetes, cardiovascular disorders, and neurodegenerative diseases. Aging research has experienced an unprecedented advance over recent years, particularly with the discovery that the rate of aging is controlled, at least to some extent, by genetic pathways and biochemical processes conserved in evolution. This review enumerates nine tentative hallmarks that represent common denominators of aging in different organisms, with special emphasis on mammalian aging. These hallmarks are: genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient-sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intercellular communication. A major challenge is to dissect the interconnectedness between the candidate hallmarks and their relative contribution to aging, with the final goal of identifying pharmaceutical targets to improve human health during aging with minimal side-effects. PMID:23746838

  12. Trends in building materials

    CSIR Research Space (South Africa)

    Mapiravana, Joseph

    2012-07-01

    Full Text Available , steel and composites research. Analysis of the building materials market situation in South Africa identified the major building material cost drivers as cement and concrete and steel. For South Africa, research and development focus has been... in South Africa be cement and concrete, light-weight steel construction, smart tiles and composite materials. Nanotechnology materials should be used for property enhancement. The building materials developed should be modularised and/or panelised...

  13. Supplementary cementitious materials

    International Nuclear Information System (INIS)

    Lothenbach, Barbara; Scrivener, Karen; Hooton, R.D.

    2011-01-01

    The use of silica rich SCMs influences the amount and kind of hydrates formed and thus the volume, the porosity and finally the durability of these materials. At the levels of substitution normally used, major changes are the lower Ca/Si ratio in the C-S-H phase and consumption of portlandite. Alumina-rich SCMs increase the Al-uptake in C-S-H and the amounts of aluminate containing hydrates. In general the changes in phase assemblages are well captured by thermodynamic modelling, although better knowledge of the C-S-H is needed. At early ages, 'filler' effects lead to an increased reaction of the clinker phases. Reaction of SCMs starts later and is enhanced with pH and temperature. Composition, fineness and the amount of glassy phase play also an important role. Due to the diverse range of SCM used, generic relations between composition, particle size, exposure conditions as temperature or relative humidity become increasingly crucial.

  14. CEO age and gender: Subsequent market performance

    Directory of Open Access Journals (Sweden)

    Marcelo Eduardo

    2016-12-01

    Full Text Available The issue of CEO age and gender vs. concurrent performance is extensively examined, but the association with subsequent performance has limited treatment in the financial literature, and with conflicting findings. In the current study, we examine the association between CEO age and gender, and subsequent company market performance using a more recent set of observations and the standard four-factor model to estimate future cumulative abnormal shareholder returns. We find that subsequent abnormal shareholder returns are marginally significantly higher for female CEOs than for their male counterparts, but no material pattern is observed between CEO age and subsequent abnormal shareholder return performance.

  15. OVARIAN AGING AND INFERTILITY TREATMENT

    Directory of Open Access Journals (Sweden)

    Helena Meden Vrtovec

    2003-12-01

    Full Text Available Background. Due to changes in the socio-economic environment the first pregnancy is being more often postponed to advanced age; an increasing number of women seek medical help for infertility in their late thirties. Degenerative processes in the ovary start as early as after 35 years of age. When the woman is over 38, the signs of hormonal changes occur (FSH, inhibin, the menstrual cycle changes, and fertility is being increasingly reduced. Infertility treatment by assisted reproduction technology (ART has proved less efficient in older than in younger women.Material and methods. In a retrospective analysis we evaluated the success rates achieved with homologous intrauterine insemination (IUI, in vitro fertilization and embryo-transfer (IVF-ET, intracytoplasmic sperm injection (ICSI, and compared them in regard to the women > 38 years vs. < 38 years.Results. After IUI the pregnancy rate in the women over 38 was 3.7% per patient (1.5% per cycle and 28.0% (9.9% in the women younger than 38 years. After IVF-ET the pregnancy rate in the over 38-year group was 16% per patient (14% per cycle, and 28% per patient (25% per cycle in the less than 38-year group. After ICSI, the pregnancy rate in the group over 38 years was 11% per patient (9% per cycle, and 25% per patient (22% per cycle in the less than 38-year group. In the analysed population, the spontaneous abortion rate was 26.0% in the group of women aged over 38 years, and 14.0% in the group of women aged less than 38 years.Conclusions. Before introduction of an ART procedure the woman with advanced age should be properly counselled and well informed about poor success of their infertility treatment and high spontaneous abortion rate.

  16. Welfare of Aged Horses

    Directory of Open Access Journals (Sweden)

    Catherine McGowan

    2011-10-01

    Full Text Available Horses form a unique and special part of their owners’ lives and aged horses are no exception. This review considers the health and management of aged horses, including the role of the owner and their perceptions of aged horses, potential threats or risks to their welfare and finally, factors affecting quality of life and euthanasia of aged horses. Owners of aged horses are concerned about the health, welfare and quality of life of their aged animals. Yet surveys of management and preventive healthcare reflect that there may be some limitations to what owners are actually achieving in practice. They show declining management as horses age, particularly for the retired horse and insufficient appropriate preventive healthcare via veterinary surgeons. The veterinary surgeon plays an essential and influential role in preventive healthcare, management of diseases and disorders and ultimately in the decision making process for euthanasia of aged horses at the end of their lives. The value of aged horses should not be underestimated by veterinarians and others working with them and the continuing care of aged horses should be regarded with the same importance as the care of younger horses with more obvious monetary value.

  17. Aging management and life extension - Containment aging study

    International Nuclear Information System (INIS)

    Tai, Tom M.; Deng, Daniel

    2004-01-01

    Bechtel is currently completing an aging study on a concrete containment structure. The target plant is a two-unit PWR plant with a generating capacity of about 850 MWe from each unit. Both units are less than 20 years old. The total electrical energy output from this plant site accounts for more than 50% of the utility's baseload operation. Although no utility in the United States has made a decision to submit a license renewal application, some have begun to investigate the feasibility of developing an life cycle management (LCM) program for a strategy to operate their plants efficiently, to investigate the financial benefit and safety implications of license renewal to operate their nuclear power plants beyond their current licensed periods, and to prepare a program plan for plant decommissioning. The LCM program includes economic, environmental, regulatory and technical aspects of continuing plant operations beyond the current license period. The Electric Power Research Institute (EPRI) has been supportive to assist utilities and owners groups in their research and development efforts to develop the technical requirements and the issues associated with important to license renewal structures. The focus of this paper is on the technical issues related to the evaluation of the material condition of the containment structure with respect to aging and the effective management of that aging. (author)

  18. Menopause accelerates biological aging

    Science.gov (United States)

    Levine, Morgan E.; Lu, Ake T.; Chen, Brian H.; Hernandez, Dena G.; Singleton, Andrew B.; Ferrucci, Luigi; Bandinelli, Stefania; Salfati, Elias; Manson, JoAnn E.; Quach, Austin; Kusters, Cynthia D. J.; Kuh, Diana; Wong, Andrew; Teschendorff, Andrew E.; Widschwendter, Martin; Ritz, Beate R.; Absher, Devin; Assimes, Themistocles L.; Horvath, Steve

    2016-01-01

    Although epigenetic processes have been linked to aging and disease in other systems, it is not yet known whether they relate to reproductive aging. Recently, we developed a highly accurate epigenetic biomarker of age (known as the “epigenetic clock”), which is based on DNA methylation levels. Here we carry out an epigenetic clock analysis of blood, saliva, and buccal epithelium using data from four large studies: the Women's Health Initiative (n = 1,864); Invecchiare nel Chianti (n = 200); Parkinson's disease, Environment, and Genes (n = 256); and the United Kingdom Medical Research Council National Survey of Health and Development (n = 790). We find that increased epigenetic age acceleration in blood is significantly associated with earlier menopause (P = 0.00091), bilateral oophorectomy (P = 0.0018), and a longer time since menopause (P = 0.017). Conversely, epigenetic age acceleration in buccal epithelium and saliva do not relate to age at menopause; however, a higher epigenetic age in saliva is exhibited in women who undergo bilateral oophorectomy (P = 0.0079), while a lower epigenetic age in buccal epithelium was found for women who underwent menopausal hormone therapy (P = 0.00078). Using genetic data, we find evidence of coheritability between age at menopause and epigenetic age acceleration in blood. Using Mendelian randomization analysis, we find that two SNPs that are highly associated with age at menopause exhibit a significant association with epigenetic age acceleration. Overall, our Mendelian randomization approach and other lines of evidence suggest that menopause accelerates epigenetic aging of blood, but mechanistic studies will be needed to dissect cause-and-effect relationships further. PMID:27457926

  19. Sandia Dynamic Materials Program Strategic Plan.

    Energy Technology Data Exchange (ETDEWEB)

    Flicker, Dawn Gustine [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Benage, John F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Desjarlais, Michael P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Knudson, Marcus D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Leifeste, Gordon T. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lemke, Raymond W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Mattsson, Thomas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wise, Jack L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-05-01

    Materials in nuclear and conventional weapons can reach multi-megabar pressures and 1000s of degree temperatures on timescales ranging from microseconds to nanoseconds. Understanding the response of complex materials under these conditions is important for designing and assessing changes to nuclear weapons. In the next few decades, a major concern will be evaluating the behavior of aging materials and remanufactured components. The science to enable the program to underwrite decisions quickly and confidently on use, remanufacturing, and replacement of these materials will be critical to NNSA’s new Stockpile Responsiveness Program. Material response is also important for assessing the risks posed by adversaries or proliferants. Dynamic materials research, which refers to the use of high-speed experiments to produce extreme conditions in matter, is an important part of NNSA’s Stockpile Stewardship Program.

  20. Plasma-material interactions

    International Nuclear Information System (INIS)

    Wilson, K.L.

    1984-01-01

    Plasma-interactive components must be resistant to erosion processes, efficient in heat removal, and effective in minimizing tritium inventory and permeation. As long as plasma edge temperatures are 50 eV, no one material can satisfy the diverse requirements imposed by these plasma materials interactions. The only solution is the design of duplex, or even more complicated, structures. The material that faces the plasma should be low atomic number, with acceptable erosion and evaporation characteristics. The substrate material must have high thermal conductivity for heat removal. Finally, materials must be selected judiciously for tritium compatibility. In conclusion, materials play a critical role in the achievement of safe and economical magnetic fusion energy. Improvements in materials have already led to many advances in present day device operation, but additional innovative materials solutions are required for the critical plasma materials interaction issues in future power reactors

  1. The future of ageing.

    Science.gov (United States)

    Hayflick, L

    2000-11-09

    Advances in our knowledge of age-associated diseases have far outpaced advances in our understanding of the fundamental ageing processes that underlie the vulnerability to these pathologies. If we are to increase human life expectancy beyond the fifteen-year limit that would result if today's leading causes of death were resolved, more attention must be paid to basic research on ageing. Determination of longevity must be distinguished from ageing to take us from the common question of why we age to a more revealing question that is rarely posed: why do we live as long as we do? But if the ability to intervene in ageing ever becomes a reality, it will be rife with unintended and undesirable consequences.

  2. Advancing materials research

    International Nuclear Information System (INIS)

    Langford, H.D.; Psaras, P.A.

    1987-01-01

    The topics discussed in this volume include historical perspectives in the fields of materials research and development, the status of selected scientific and technical areas, and current topics in materials research. Papers are presentd on progress and prospects in metallurgical research, microstructure and mechanical properties of metals, condensed-matter physics and materials research, quasi-periodic crystals, and new and artifically structured electronic and magnetic materials. Consideration is also given to materials research in catalysis, advanced ceramics, organic polymers, new ways of looking at surfaces, and materials synthesis and processing

  3. Advanced energy materials

    CERN Document Server

    Tiwari, Ashutosh

    2014-01-01

    An essential resource for scientists designing new energy materials for the vast landscape of solar energy conversion as well as materials processing and characterization Based on the new and fundamental research on novel energy materials with tailor-made photonic properties, the role of materials engineering has been to provide much needed support in the development of photovoltaic devices. Advanced Energy Materials offers a unique, state-of-the-art look at the new world of novel energy materials science, shedding light on the subject's vast multi-disciplinary approach The book focuses p

  4. Materials science and engineering

    Energy Technology Data Exchange (ETDEWEB)

    Lesuer, D.R.

    1997-02-01

    During FY-96, work within the Materials Science and Engineering Thrust Area was focused on material modeling. Our motivation for this work is to develop the capability to study the structural response of materials as well as material processing. These capabilities have been applied to a broad range of problems, in support of many programs at Lawrence Livermore National Laboratory. These studies are described in (1) Strength and Fracture Toughness of Material Interfaces; (2) Damage Evolution in Fiber Composite Materials; (3) Flashlamp Envelope Optical Properties and Failure Analysis; (4) Synthesis and Processing of Nanocrystalline Hydroxyapatite; and (5) Room Temperature Creep Compliance of Bulk Kel-E.

  5. Materials for breeding blankets

    International Nuclear Information System (INIS)

    Mattas, R.F.; Billone, M.C.

    1995-09-01

    There are several candidate concepts for tritium breeding blankets that make use of a number of special materials. These materials can be classified as Primary Blanket Materials, which have the greatest influence in determining the overall design and performance, and Secondary Blanket Materials, which have key functions in the operation of the blanket but are less important in establishing the overall design and performance. The issues associated with the blanket materials are specified and several examples of materials performance are given. Critical data needs are identified

  6. Materials for breeding blankets

    International Nuclear Information System (INIS)

    Mattas, R.F.; Billone, M.C.

    1996-01-01

    There are several candidate concepts for tritium breeding blankets that make use of a number of special materials. These materials can be classified as primary blanket materials, which have the greatest influence in determining the overall design and performance, and secondary blanket materials, which have key functions in the operation of the blanket but are less important in establishing the overall design and performance. The issues associated with the blanket materials are specified and several examples of materials performance are given. Critical data needs are identified. (orig.)

  7. Materials by design

    International Nuclear Information System (INIS)

    Eberhardt, J.; Hay, P.J.; Carpenter, J.A. Jr.

    1986-01-01

    Major developments in materials characterization instrumentation over the past decade have helped significantly to elucidate complex processes and phenomena connected with the microstructure of materials and interfacial interactions. Equally remarkable advances in theoretical models and computer technology also have been taking place during this period. These latter now permit, for example, in selected cases the computation of material structures and bonding and the prediction of some material properties. Two assessments of the state of the art of instrumental techniques and theoretical methods for the study of material structures and properties have recently been conducted. This paper discusses aspects from these assessments of computational theoretical methods apply to materials

  8. The aging lung

    Directory of Open Access Journals (Sweden)

    Lowery EM

    2013-11-01

    Full Text Available Erin M Lowery,1 Aleah L Brubaker,2 Erica Kuhlmann,1 Elizabeth J Kovacs31Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine at Loyola University Medical Center, 2Loyola University Stritch School of Medicine, 3Department of Surgery, Loyola University Medical Center, Maywood, IL, USAAbstract: There are many age-associated changes in the respiratory and pulmonary immune system. These changes include decreases in the volume of the thoracic cavity, reduced lung volumes, and alterations in the muscles that aid respiration. Muscle function on a cellular level in the aging population is less efficient. The elderly population has less pulmonary reserve, and cough strength is decreased in the elderly population due to anatomic changes and muscle atrophy. Clearance of particles from the lung through the mucociliary elevator is decreased and associated with ciliary dysfunction. Many complex changes in immunity with aging contribute to increased susceptibility to infections including a less robust immune response from both the innate and adaptive immune systems. Considering all of these age-related changes to the lungs, pulmonary disease has significant consequences for the aging population. Chronic lower respiratory tract disease is the third leading cause of death in people aged 65 years and older. With a large and growing aging population, it is critical to understand how the body changes with age and how this impacts the entire respiratory system. Understanding the aging process in the lung is necessary in order to provide optimal care to our aging population. This review focuses on the nonpathologic aging process in the lung, including structural changes, changes in muscle function, and pulmonary immunologic function, with special consideration of obstructive lung disease in the elderly.Keywords: aging, lung, pulmonary immunology, COPD

  9. Anatomy of ageing face.

    Science.gov (United States)

    Ilankovan, V

    2014-03-01

    Ageing is a biological process that results from changes at a cellular level, particularly modification of mRNA. The face is affected by the same physiological process and results in skeletal, muscular, and cutaneous ageing; ligamentous attenuation, descent of fat, and ageing of the appendages. I describe these changes on a structural and clinical basis and summarise possible solutions for a rejuvenation surgeon. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  10. Cave age determination

    International Nuclear Information System (INIS)

    Anon.

    1998-01-01

    To determine the age of a cave we have to determine the age of elements which were created at the same moment when the cave was. Usually a cave is dug out by infiltration of acid waters. During this alteration process rocks free some aluminium and potassium ions. In Carlsbad and Lechuguilla caves, scientists have found alunite, this aluminium and potassium sulfate can be dated by using the carbon method of age determination. (A.C.)

  11. Anorexia of Aging.

    Science.gov (United States)

    Visvanathan, Renuka

    2015-08-01

    The anorexia of aging is common, leading to adverse health consequences. As populations age, the impacts from anorexia in the older population are set to increase. Only greater awareness will allow for prevention or early intervention. This article discusses the physiologic anorexia of aging, highlights contributing factors, and proposes management strategies, including screening, especially in primary care. Many neuroendocrine factors have been implicated in the pathophysiology; it is clear that further human research is necessary if there is to be a pharmacologic breakthrough. There are currently no approved pharmacologic treatment strategies to prevent or treat the anorexia of aging. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Sexual activity and aging.

    Science.gov (United States)

    Ni Lochlainn, Mary; Kenny, Rose Anne

    2013-08-01

    Sexuality is an important component of emotional and physical intimacy that men and women experience throughout their lives. Research suggesting that a high proportion of men and women remain sexually active well into later life refutes the prevailing myth that aging and sexual dysfunction are inexorably linked. Age-related physiological changes do not render a meaningful sexual relationship impossible or even necessarily difficult. Many of these physiological changes are modifiable. There are various therapeutic options available to patients to achieve maximum sexual capacity in old age. This article reviews the prevalence of sexual activity among older adults, the problems these adults encounter with sexual activity, and the role of the health care professional in addressing these problems. The physiological sex-related changes that occur as part of the normal aging process in men and women are reviewed, as well as the effect of age-related physical and psychological illness on sexual function. The attitudes and perceptions of the media and general public toward sexual activity and aging are summarized. An understanding of the sexual changes that accompany the aging process may help general practitioners and other doctors to give practical and useful advice on sexuality as well as refute the misconception that aging equates to celibacy. A thorough awareness of this aspect of older people's quality of life can raise meaningful expectations for aging patients. Copyright © 2013 American Medical Directors Association, Inc. Published by Elsevier Inc. All rights reserved.

  13. We Are Ageing

    Directory of Open Access Journals (Sweden)

    Genovefa D. Kolovou

    2014-01-01

    Full Text Available Ageing and longevity is unquestioningly complex. Several thoughts and mechanisms of ageing such as pathways involved in oxidative stress, lipid and glucose metabolism, inflammation, DNA damage and repair, growth hormone axis and insulin-like growth factor (GH/IGF, and environmental exposure have been proposed. Also, some theories of ageing were introduced. To date, the most promising leads for longevity are caloric restriction, particularly target of rapamycin (TOR, sirtuins, hexarelin and hormetic responses. This review is an attempt to analyze the mechanisms and theories of ageing and achieving longevity.

  14. Hodgkin's disease and age

    DEFF Research Database (Denmark)

    Specht, L.; Nissen, N.I.

    1989-01-01

    506 unselected, previously untreated patients with Hodgkin's disease were treated at the Finsen Institute between 1969 and 1983. The prognostic significance of age, sex, stage, systemic symptoms, histologic subtype, number of involved nodal regions, total tumour burden (peripheral + intrathoracic...... modality, stage, and total tumour burden, whereas age had no prognostic significance. With regard to death from Hodgkin's disease only age and total tumour burden had independent significance. The significance of age would seem to stem from the fact that some older patients could not be given adequate...

  15. Evolutionary perspectives on ageing.

    Science.gov (United States)

    Reichard, Martin

    2017-10-01

    From an evolutionary perspective, ageing is a decrease in fitness with chronological age - expressed by an increase in mortality risk and/or decline in reproductive success and mediated by deterioration of functional performance. While this makes ageing intuitively paradoxical - detrimental to individual fitness - evolutionary theory offers answers as to why ageing has evolved. In this review, I first briefly examine the classic evolutionary theories of ageing and their empirical tests, and highlight recent findings that have advanced our understanding of the evolution of ageing (condition-dependent survival, positive pleiotropy). I then provide an overview of recent theoretical extensions and modifications that accommodate those new discoveries. I discuss the role of indeterminate (asymptotic) growth for lifetime increases in fecundity and ageing trajectories. I outline alternative views that challenge a universal existence of senescence - namely the lack of a germ-soma distinction and the ability of tissue replacement and retrogression to younger developmental stages in modular organisms. I argue that rejuvenation at the organismal level is plausible, but includes a return to a simple developmental stage. This may exempt a particular genotype from somatic defects but, correspondingly, removes any information acquired during development. A resolution of the question of whether a rejuvenated individual is the same entity is central to the recognition of whether current evolutionary theories of ageing, with their extensions and modifications, can explain the patterns of ageing across the Tree of Life. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Radiation Effects on Spacecraft Structural Materials

    International Nuclear Information System (INIS)

    Wang, Jy-An J.; Ellis, Ronald J.; Hunter, Hamilton T.; Singleterry, Robert C. Jr.

    2002-01-01

    Research is being conducted to develop an integrated technology for the prediction of aging behavior for space structural materials during service. This research will utilize state-of-the-art radiation experimental apparatus and analysis, updated codes and databases, and integrated mechanical and radiation testing techniques to investigate the suitability of numerous current and potential spacecraft structural materials. Also included are the effects on structural materials in surface modules and planetary landing craft, with or without fission power supplies. Spacecraft structural materials would also be in hostile radiation environments on the surface of the moon and planets without appreciable atmospheres and moons around planets with large intense magnetic and radiation fields (such as the Jovian moons). The effects of extreme temperature cycles in such locations compounds the effects of radiation on structural materials. This paper describes the integrated methodology in detail and shows that it will provide a significant technological advance for designing advanced spacecraft. This methodology will also allow for the development of advanced spacecraft materials through the understanding of the underlying mechanisms of material degradation in the space radiation environment. Thus, this technology holds a promise for revolutionary advances in material damage prediction and protection of space structural components as, for example, in the development of guidelines for managing surveillance programs regarding the integrity of spacecraft components, and the safety of the aging spacecraft. (authors)

  17. Nuclear graphite ageing and turnaround

    International Nuclear Information System (INIS)

    Marsden, B.J.; Hall, G.N.; Smart, J.

    2001-01-01

    Graphite moderated reactors are being operated in many countries including, the UK, Russia, Lithuania, Ukraine and Japan. Many of these reactors will operate well into the next century. New designs of High Temperature Graphite Moderated Reactors (HTRS) are being built in China and Japan. The design life of these graphite-moderated reactors is governed by the ageing of the graphite core due to fast neutron damage, and also, in the case of carbon dioxide cooled reactors by the rate of oxidation of the graphite. Nuclear graphites are polycrystalline in nature and it is the irradiation-induced damage to the individual graphite crystals that determines the material property changes with age. The life of a graphite component in a nuclear reactor can be related to the graphite irradiation induced dimensional changes. Graphites typically shrink with age, until a point is reached where the shrinkage stops and the graphite starts to swell. This change from shrinkage to swelling is known as ''turnaround''. It is well known that pre-oxidising graphite specimens caused ''turnaround'' to be delayed, thus extending the life of the graphite, and hence the life of the reactor. However, there was no satisfactory explanation of this behaviour. This paper presents a numerical crystal based model of dimensional change in graphite, which explains the delay in ''turnaround'' in the pre-oxidised specimens irradiated in a fast neutron flux, in terms of crystal accommodation and orientation and change in compliance due to radiolytic oxidation. (author)

  18. 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

  19. Accelerated materials evaluation for nuclear applications

    Energy Technology Data Exchange (ETDEWEB)

    Griffiths, M., E-mail: malcolm.griffiths@queensu.ca [Department of Mechanical and Materials Engineering, Queen' s University, Kingston, Ontario, K7L 3N6 (Canada); Walters, L. [Canadian Nuclear Laboratories, Chalk River, ON, K0J 1J0 (Canada); Greenwood, L.R. [Pacific Northwest National Laboratory, Richland, WA, 99352 (United States); Garner, F.A. [Radiation Effects Consulting, Richland, WA, 99352 (United States)

    2017-05-15

    This paper addresses the opportunities and complexities of using materials test reactors with high neutron fluxes to perform accelerated studies of material aging in power reactors operating at lower neutron fluxes and with different neutron flux spectra. Radiation damage and gas production in different reactors have been compared using the code, SPECTER. This code provides a common standard from which to compare neutron damage data generated by different research groups using a variety of reactors.

  20. Investigation of plutonium abundance and age analysis

    Energy Technology Data Exchange (ETDEWEB)

    Huailong, Wu; Jian, Gong; Fanhua, Hao [China Academy of Engineering Physics, Mianyang (China). Inst. of Nuclear Physics and Chemistry

    2007-06-15

    Based on spectra analysis software, all of the plutonium material peak counts are analyzed. Relatively efficiency calibration is done by the non-coupling peaks of {sup 239}Pu. By using the known isotopes half life and yield, the coupling peaks counts are allocated by non-coupling peaks, consequently the atom ratios of each isotope are gotten. The formula between atom ratio and abundance or age is deduced by plutonium material isotopes decay characteristic. And so the abundance and age of plutonium material is gotten. After some re- peat measurements for a plutonium equipment are completed, a comparison between our analysis results and PC-FRAM and the owner's reference results are done. (authors)

  1. Materials risk analysis.

    Science.gov (United States)

    2010-02-01

    State highway authorities routinely examine the quality of the materials used to build highway construction projects. Some : materials are tested, some are accepted through a manufacturers certification of quality or compliance, some are physicall...

  2. Smart hydrogel functional materials

    CERN Document Server

    Chu, Liang-Yin; Ju, Xiao-Jie

    2014-01-01

    This book systematically introduces smart hydrogel functional materials with the configurations ranging from hydrogels to microgels. It serves as an excellent reference for designing and fabricating artificial smart hydrogel functional materials.

  3. Practical materials characterization

    CERN Document Server

    2014-01-01

    Presents cross-comparison between materials characterization techniquesIncludes clear specifications of strengths and limitations of each technique for specific materials characterization problemFocuses on applications and clear data interpretation without extensive mathematics

  4. Bridged graphite oxide materials

    Science.gov (United States)

    Herrera-Alonso, Margarita (Inventor); McAllister, Michael J. (Inventor); Aksay, Ilhan A. (Inventor); Prud'homme, Robert K. (Inventor)

    2010-01-01

    Bridged graphite oxide material comprising graphite sheets bridged by at least one diamine bridging group. The bridged graphite oxide material may be incorporated in polymer composites or used in adsorption media.

  5. Sustainable Materials Management

    Science.gov (United States)

    To introduce businesses, NGOs, and government officials to the concept of Sustainable Materials Management (SMM). To provide tools to allow stakeholders to take a lifecycle approach managing their materials, & to encourage them to join a SMM challenge.

  6. Injection Laryngoplasty Materials

    OpenAIRE

    Haldun Oðuz

    2013-01-01

    Injection laryngoplasty is one of the treatment options for voice problems. In the recent years, more safe and more biocompatible injection materials are available on the market. Long and short term injection materials are discussed in this review.

  7. Materials Science and Engineering |

    Science.gov (United States)

    Engineering? What Is Materials Science and Engineering? MSE combines engineering, physics and chemistry to solve problems in nanotechnology, biotechnology, information technology, energy, manufacturing, and more ,' which could replace steel. Materials Science and Mechanical Engineering Professors work together to

  8. Molecules to Materials

    Indian Academy of Sciences (India)

    the School of Chemistry, ... Design and fabrication of molecular materials combines ... insights into materials gained through condensed matter ... The most important characteristic of liquid crystals is that they exhibit fluid nature and at the same.

  9. Nanostructured composite reinforced material

    Science.gov (United States)

    Seals, Roland D [Oak Ridge, TN; Ripley, Edward B [Knoxville, TN; Ludtka, Gerard M [Oak Ridge, TN

    2012-07-31

    A family of materials wherein nanostructures and/or nanotubes are incorporated into a multi-component material arrangement, such as a metallic or ceramic alloy or composite/aggregate, producing a new material or metallic/ceramic alloy. The new material has significantly increased strength, up to several thousands of times normal and perhaps substantially more, as well as significantly decreased weight. The new materials may be manufactured into a component where the nanostructure or nanostructure reinforcement is incorporated into the bulk and/or matrix material, or as a coating where the nanostructure or nanostructure reinforcement is incorporated into the coating or surface of a "normal" substrate material. The nanostructures are incorporated into the material structure either randomly or aligned, within grains, or along or across grain boundaries.

  10. Supplements to Textbook Materials.

    Science.gov (United States)

    Holmes, Ken

    1994-01-01

    Describes the many kinds of materials that English teachers can draw upon to enrich and expand students' experiences with literature. Outlines ancillary materials used to supplement the study of William Shakespeare's "Julius Caesar." (HB)

  11. Bulletin of Materials Science

    Indian Academy of Sciences (India)

    Low temperature preparation of some perovskites La2MM'O6 (M,M'=Cr,Mn,Fe ... Inorganic materials for optical data storage -- S K Date ... Dielectric and polarization studies on some organic materials -- B jagannadh and Lalitha Sirdeshmukh.

  12. Erodibility of cemented materials

    CSIR Research Space (South Africa)

    Gass, BG

    1993-03-01

    Full Text Available The use of stabilised layers is cost effective in road construction in South Africa. Some stabilised materials have however been found to be susceptible to erosion. To identify erodible materials the Erosion Test was developed in 1989...

  13. Contact materials for nanoelectronics

    KAUST Repository

    Alshareef, Husam N.; Quevedo-Ló pez, Manuel Angel Quevedo; Majhi, Prashant

    2011-01-01

    In this article, we review current research activities in contact material development for electronic and nanoelectronic devices. A fundamental issue in contact materials research is to understand and control interfacial reactions and phenomena

  14. Materials Genome Initiative

    Science.gov (United States)

    Vickers, John

    2015-01-01

    The Materials Genome Initiative (MGI) project element is a cross-Center effort that is focused on the integration of computational tools to simulate manufacturing processes and materials behavior. These computational simulations will be utilized to gain understanding of processes and materials behavior to accelerate process development and certification to more efficiently integrate new materials in existing NASA projects and to lead to the design of new materials for improved performance. This NASA effort looks to collaborate with efforts at other government agencies and universities working under the national MGI. MGI plans to develop integrated computational/experimental/ processing methodologies for accelerating discovery and insertion of materials to satisfy NASA's unique mission demands. The challenges include validated design tools that incorporate materials properties, processes, and design requirements; and materials process control to rapidly mature emerging manufacturing methods and develop certified manufacturing processes

  15. Cognitive Age: A New Multidimensional Approach to Measuring Age Identity.

    Science.gov (United States)

    Barak, Benny

    1987-01-01

    Conducted exploratory field study to examine how age-concepts are experienced and to assess relationship of age identities to each other. Proposes Cognitive Age as a new multidimensional age scale that merges the standard scale, Identity Age, and Personal Age. Study results attest to Cognitive Age scale's reliability and validity. (Author/NB)

  16. Constitutive modelling of creep-ageing behaviour of peak-aged aluminium alloy 7050

    Directory of Open Access Journals (Sweden)

    Yang Yo-Lun

    2015-01-01

    Full Text Available The creep-ageing behaviour of a peak-aged aluminium alloy 7050 was investigated under different stress levels at 174 ∘C for up to 8 h. Interrupted creep tests and tensile tests were performed to investigate the influences of creep-ageing time and applied stress on yield strength. The mechanical testing results indicate that the material exhibits an over-ageing behaviour which increases with the applied stress level during creep-ageing. As creep-ageing time approaches 8 h, the material's yield strength under different stress levels gradually converge, which suggests that the difference in mechanical properties under different stress conditions can be minimised. This feature can be advantageous in creep-age forming to the formed components such that uniformed mechanical properties across part area can be achieved. A set of constitutive equations was calibrated using the mechanical test results and the alloy-specific material constants were obtained. A good agreement is observed between the experimental and calibrated results.

  17. Thermal-aging evaluation of on site aged cast duplex stainless steel

    International Nuclear Information System (INIS)

    Yamada, Takuyo; Fujii, Katsuhiko; Aoki, Masanori; Arioka, Koji

    2013-01-01

    In this study, thermal-aging evaluation has been performed using service aged elbow pipe in PWR plant, aged at 320degC for 196,500h. As a result, micro Vickers hardness of ferrite in service material (SCS14A), HV(0.025) was 616∼630. Since micro Vickers hardness of un-aged ferrite phase is about HV(0.025)=300 in commercial SCS14A, the increasing of ferrite hardness during aging was 300. Cr-rich and Fe-rich regions were observed in the ferrite phase using Atom-probe analysis. In addition, Ni, Si and Mo clustering were also observed in the ferrite phase. So the ferrite phase was hardened caused by these micro-structural changes. Micro Vickers hardness of austenite phase, HV(0.025) was 155∼180. Since micro Vickers hardness of un-aged austenite phase is about HV(0.025)=180∼200, and no micro-structural change was observed in the austenite phase, so on change was observed in the austenite phase during aging. To compare the micro Vickers hardness of ferrite in service and accelerated materials using activation energy, Q=100 kJ/mol, the ferrite hardness of in service material was very low rather than predictive line. This seems the activation energy was too conservative. (author)

  18. Analysis of irradiated materials

    International Nuclear Information System (INIS)

    Bellamy, B.A.

    1988-01-01

    Papers presented at the UKAEA Conference on Materials Analysis by Physical Techniques (1987) covered a wide range of techniques as applied to the analysis of irradiated materials. These varied from reactor component materials, materials associated with the Authority's radwaste disposal programme, fission products and products associated with the decommissioning of nuclear reactors. An invited paper giving a very comprehensive review of Laser Ablation Microprobe Mass Spectroscopy (LAMMS) was included in the programme. (author)

  19. Fuels and auxiliary materials

    International Nuclear Information System (INIS)

    Svab, V.

    A brief survey is given of the problems of fuels, fuel cans, absorption and moderator materials proceeding from the papers presented at the 1971 4th Geneva Conference on the Peaceful Uses of Nuclear Energy and the 1970 IAEA Conference in New York. Attention is focused on the behaviour of fuel and fuel can materials for thermal and fast reactors during irradiation, radiation stability of absorption materials and the effects of radiation on concrete and on moderator materials. (Z.M.)

  20. Contributions to materials science

    International Nuclear Information System (INIS)

    Asbeck, O.W.; Matucha, K.H.

    1989-01-01

    The ten papers presented at a festive colloquium held on November 14, 1988 in Frankfurt to honour Prof. Peter Wincierz deal with the texture and mechanical anisotropy of zirconium alloys (by E. Tenckhoff), materials for cladding tubes (H. Boehm), aluminium materials achieved by near technology (W. Bunk), dispersion-strengthened materials (H. Fischmeister), materials for plain bearings (K.H. Matucha), and the archeometallurgy of copper (H.-G. Bachmann). (MM) [de

  1. Modern electronic materials

    CERN Document Server

    Watkins, John B

    2013-01-01

    Modern Electronic Materials focuses on the development of electronic components. The book first discusses the history of electronic components, including early developments up to 1900, developments up to World War II, post-war developments, and a comparison of present microelectric techniques. The text takes a look at resistive materials. Topics include resistor requirements, basic properties, evaporated film resistors, thick film resistors, and special resistors. The text examines dielectric materials. Considerations include basic properties, evaporated dielectric materials, ceramic dielectri

  2. Machinability of advanced materials

    CERN Document Server

    Davim, J Paulo

    2014-01-01

    Machinability of Advanced Materials addresses the level of difficulty involved in machining a material, or multiple materials, with the appropriate tooling and cutting parameters.  A variety of factors determine a material's machinability, including tool life rate, cutting forces and power consumption, surface integrity, limiting rate of metal removal, and chip shape. These topics, among others, and multiple examples comprise this research resource for engineering students, academics, and practitioners.

  3. Materials Genome Initiative Element

    Science.gov (United States)

    Vickers, John

    2015-01-01

    NASA is committed to developing new materials and manufacturing methods that can enable new missions with ever increasing mission demands. Typically, the development and certification of new materials and manufacturing methods in the aerospace industry has required more than 20 years of development time with a costly testing and certification program. To reduce the cost and time to mature these emerging technologies, NASA is developing computational materials tools to improve understanding of the material and guide the certification process.

  4. Advanced energy materials (Preface)

    Science.gov (United States)

    Titus, Elby; Ventura, João; Araújo, João Pedro; Campos Gil, João

    2017-12-01

    Advances in material science make it possible to fabricate the building blocks of an entirely new generation of hierarchical energy materials. Recent developments were focused on functionality and areas connecting macroscopic to atomic and nanoscale properties, where surfaces, defects, interfaces and metastable state of the materials played crucial roles. The idea is to combine both, the top-down and bottom-up approach as well as shape future materials with a blend of both the paradigms.

  5. Behaviour of organic materials in radiation environment

    CERN Document Server

    Tavlet, M

    2000-01-01

    Radiation effects in polymers are reminded together with the ageing factors. Radiation-ageing results are mainly discussed about thermosetting insulators, structural composites and cable-insulating materials. Some hints are given about high-voltage insulations, cooling fluids, organic scintillators and light-guides. Some parameters to be taken into account for the estimate of the lifetime of components in radiation environment are also shown. (23 refs).

  6. Learning and Active Aging

    Science.gov (United States)

    Boulton-Lewis, Gillian M.; Buys, Laurie; Lovie-Kitchin, Jan

    2006-01-01

    Learning is an important aspect of aging productively. This paper describes results from 2645 respondents (aged from 50 to 74+ years) to a 165-variable postal survey in Australia. The focus is on learning and its relation to work; social, spiritual, and emotional status; health; vision; home; life events; and demographic details. Clustering…

  7. Biology of ageing

    DEFF Research Database (Denmark)

    Rattan, Suresh

    2015-01-01

    Living systems owe their survival and health to a series of complex biochemical pathways of maintenance and repair. These defense systems create the homeodynamic space of an individual, which is characterized by stress tolerance, molecular damage control and continuous remodeling. Ageing, age-rel...

  8. Sexuality and Aging.

    Science.gov (United States)

    Hinkley, Nancy E.

    Literature on sexuality and aging and Maslow's hierarchy of needs (which include physiological needs, safety and security needs, belongingness needs, esteem needs, and the need for self-actualization) are used in this paper to identify at each level the needs of the aging individual as they derive from his sexuality in order to provide a…

  9. Sexuality, aging, and dementia.

    Science.gov (United States)

    Benbow, Susan Mary; Beeston, Derek

    2012-07-01

    Sexuality in later life and its relationship to dementia is a neglected topic: greater understanding of the area has the potential to contribute to the quality of life of people with dementia, their family members, and formal carers. We review current knowledge about sexuality, aging, and dementia. We undertook a review of the recent literature to examine of the following areas: what is known about sexuality and aging, and about attitudes to sexuality and aging; what is known about the relevance of sexuality and aging to people living with dementia and their care; and the management of sexual behaviors causing concern to others. Sexual activity decreases in frequency with increasing age but many older people remain sexually active; there is no age limit to sexual responsiveness; and sexuality is becoming more important to successive cohorts of older people, including people living with dementia and gay, lesbian, bisexual, and transgendered elderly people. Attitudes and beliefs toward sexuality and aging are strongly influenced by stereotypes and myths, not only among the general public but also among those working in health and social care. Professional bodies should include sexuality, aging, and dementia in their training curricula. More work is needed on the impact of environmental issues, particularly in group living situations, on older adults' sexuality, and on consent issues. Ethical decision-making frameworks can be useful in practice. Organizations should investigate how to support staff in avoiding a problem-orientated approach and focus on providing holistic person-centered care.

  10. Age and Scientific Performance.

    Science.gov (United States)

    Cole, Stephen

    1979-01-01

    The long-standing belief that age is negatively associated with scientific productivity and creativity is shown to be based upon incorrect analysis of data. Studies reported in this article suggest that the relationship between age and scientific performance is influenced by the operation of the reward system. (Author)

  11. Healthy ageing at work

    NARCIS (Netherlands)

    de Jong, Marlon; Jolij, Jacob; Lorist, Monicque

    2016-01-01

    Demographic ageing in the Western world means that the average age of the working population is increasing. This has major consequences for the labour process. Growing older is linked to physical and cognitive changes that can influence the performance of tasks. We are faced with an important

  12. Healthy ageing at work

    NARCIS (Netherlands)

    de Jong, Marlon; Jolij, Jacob; Lorist, Monicque

    2016-01-01

    Background Demographic ageing in the Western world means that the average age of the working population is increasing. This has major consequences for the labour process. Growing older is linked to physical and cognitive changes that can influence the performance of tasks. We are faced with an

  13. Brain atrophy during aging

    International Nuclear Information System (INIS)

    Matsuzawa, Taiju; Takeda, Shumpei; Hatazawa, Jun

    1985-01-01

    Age-related brain atrophy was investigated in thousands of persons with no neurologic disturbances using X-CT and NMR-CT and following results were obtained. Brain atrophy was minimal in 34 -- 35 years old in both sexes, increased exponentially to the increasing age after 34 -- 35 years, and probably resulted in dementia, such as vascular or multiinfarct dementia. Brain atrophy was significantly greater in men than in women at all ages. Brain volumes were maximal in 34 -- 35 years old in both sexes with minimal individual differences which increased proportionally to the increasing age. Remarkable individual differences in the extents of brain atrophy (20 -- 30 %) existed among aged subjects. Some aged subjects had little or no atrophy of their brains, as seen in young subjects, and others had markedly shrunken brains associated with senility. From these results there must be pathological factors promoting brain atrophy with a great individual difference. We have studied the relation of intelligence to brain volume, and have ascertained that progression of brain atrophy was closely related to loss of mental activities independently of their ages. Our longitudinal study has revealed that the most important factors promoting brain atrophy during aging was decrease in the cerebral blood flow. MNR-CT can easily detected small infarction (lacunae) and edematous lesions resulting from ischemia and hypertensive encephalopathy, while X-CT can not. Therefore NMR-CT is very useful for detection of subtle changes in the brain. (J.P.N.)

  14. Biodemography of human ageing

    DEFF Research Database (Denmark)

    Vaupel, James W

    2010-01-01

    Human senescence has been delayed by a decade. This finding, documented in 1994 and bolstered since, is a fundamental discovery about the biology of human ageing, and one with profound implications for individuals, society and the economy. Remarkably, the rate of deterioration with age seems...

  15. Successful ageing for psychiatrists.

    Science.gov (United States)

    Peisah, Carmelle

    2016-04-01

    This paper aims to explore the concept and determinants of successful ageing as they apply to psychiatrists as a group, and as they can be applied specifically to individuals. Successful ageing is a heterogeneous, inclusive concept that is subjectively defined. No longer constrained by the notion of "super-ageing", successful ageing can still be achieved in the face of physical and/or mental illness. Accordingly, it remains within the reach of most of us. It can, and should be, person-specific and individually defined, specific to one's bio-psycho-social and occupational circumstances, and importantly, reserves. Successful professional ageing is predicated upon insight into signature strengths, with selection of realistic goal setting and substitution of new goals, given the dynamic nature of these constructs as we age. Other essential elements are generativity and self-care. Given that insight is key, taking a regular stock or inventory of our reserves across bio-psycho-social domains might be helpful. Importantly, for successful ageing, this needs to be suitably matched to the professional task and load. This lends itself to a renewable personal ageing plan, which should be systemically adopted with routine expectations of self-care and professional responsibility. © The Royal Australian and New Zealand College of Psychiatrists 2015.

  16. Aging of SRC liquids

    Science.gov (United States)

    Hara, T.; Jones, L.; Tewari, K. C.; Li, N. C.

    1981-02-01

    The viscosity of SRC-LL liquid increases when subjected to accelerated aging by bubbling oxygen in the presence of copper strip at 62°C. Precipitates are formed and can be separated from the aged liquid by Soxhlet extraction with pentane. A 30-70 blend of SRC-I with SRC-LL was subjected to oxygen aging in the absence of copper, and the viscosity increased dramatically after 6 days at 62°. The content of preasphaltene and its molecular size increase with time of aging, accompanied by decrease of asphaltene and pentane-soluble contents. For the preasphaltene fraction on aging, gel permeation chromatography shows formation of larger particles. ESR experiments show that with oxygen aging, spin concentration in the preasphaltene fraction decreases. Perhaps some semiquinone, together with di- and tri-substituted phenoxy radicals, generated by oxygen aging of the coal liquid, interact with the free radicals already present in coal to yield larger particles and reduce free radical concentration. We are currently using the very high-field (600-MHz) NMR spectrometer at Mellon Institute to determine changes in structural parameters before and after aging of SRC-II and its chromatographically separated fractions.

  17. Healthy ageing at work

    NARCIS (Netherlands)

    de Jong, Marlon; Jolij, Jacob; Lorist, Monicque

    2015-01-01

    Demographic ageing in the Western world means that the average age of the working population is increasing. This has major consequences for the labour process. Growing older is linked to physical and cognitive changes which can influence performance of tasks. We are faced with an important

  18. Age, Wage and Productivity

    NARCIS (Netherlands)

    van Ours, J.C.; Stoeldraijer, L.

    2010-01-01

    Previous empirical studies on the effect of age on productivity and wages find contradicting results. Some studies find that if workers grow older there is an increasing gap between productivity and wages, i.e. wages increase with age while productivity does not or does not increase at the same

  19. Unemployment Dynamics and Age

    NARCIS (Netherlands)

    Berg, van den G.J.; Gijsbert, A.; Lomwel, van C.; Ours, van Jan C.

    1998-01-01

    Youth unemployment is an issue of primary concern in WesternEuropean countries. In this paper we analyze dynamics in unemployment foryouths, adults (prime-aged individuals), and elderly. We use quarterly Frenchunemployment data, stratified by gender, age group, and duration, over theperiod

  20. Reliability of structural materials in nuclear industry

    International Nuclear Information System (INIS)

    Pinard Legry, G.

    1996-01-01

    The reliability of nuclear installations is a fundamental point for the exploitation of nuclear energy. It requires an extensive knowledge of the behaviour of materials in the operating conditions and during the expected service life of the installations. In nuclear power plants multiple risks of failure can exist and are expressed by corrosion and deformation phenomena or by modification in the mechanical characteristics of materials. The knowledge of the evolution with time of a given material requires to take into account the data relative to the material itself, to its environment and to the physical conditions of this environment. The study of materials aging needs a more precise knowledge of the kinetics of phenomena at any scale and of their interactions, and a micro- or macro-modeling of their behaviour during long periods of time. This paper gives an overview of the aging phenomena that occur in the structural materials involved in PWR and fast neutron reactors: thermal aging, generalized corrosion, corrosion under constraint, intergranular corrosion, crack growth under loading, wear, irradiation etc.. (J.S.)

  1. Computing and Material

    DEFF Research Database (Denmark)

    Ramsgaard Thomsen, Mette; Tamke, Martin

    2013-01-01

    The digital is often said to bring us away from material. The adverse is true: digital design and fabrication grants new interfaces towards material and allows architectural design to engage with material on architectural scale in a way that is further reaching than ever before....

  2. Advances in dental materials.

    Science.gov (United States)

    Fleming, Garry J P

    2014-05-01

    The dental market is replete with new resorative materials marketed on the basis of novel technological advances in materials chemistry, bonding capability or reduced operator time and/or technique sensitivity. This paper aims to consider advances in current materials, with an emphasis on their role in supporting contemporary clinical practice.

  3. Transport of radioactive materials

    International Nuclear Information System (INIS)

    2013-01-01

    This ninth chapter presents de CNEN-NE--5.01 norm 'Transport of radioactive material'; the specifications of the radioactive materials for transport; the tests of the packages; the requests for controlling the transport and the responsibilities during the transport of radioactive material

  4. Materials for Space Exploration

    Science.gov (United States)

    Robertson, Luke B.; Williams, Martha

    2010-01-01

    Topics include a lab overview, testing and processing equipment, hemochromic hydrogen sensors, antimicrobial materials, wire system materials, CNT ink formulations, CNT ink dust screens, CNT ink printed circuitry, cryogenic materials development, fire and polymers, the importance of lighting, electric lighting systems, LED for plant growth, and carbon nanotube fiber filaments.

  5. Fusion reactor materials

    Energy Technology Data Exchange (ETDEWEB)

    none,

    1989-01-01

    This paper discuses the following topics on fusion reactor materials: irradiation, facilities, test matrices, and experimental methods; dosimetry, damage parameters, and activation calculations; materials engineering and design requirements; fundamental mechanical behavior; radiation effects; development of structural alloys; solid breeding materials; and ceramics.

  6. Isotope research materials

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    Preparation of research isotope materials is described. Topics covered include: separation of tritium from aqueous effluents by bipolar electrolysis; stable isotope targets and research materials; radioisotope targets and research materials; preparation of an 241 Am metallurgical specimen; reactor dosimeters; ceramic and cermet development; fission-fragment-generating targets of 235 UO 2 ; and wire dosimeters for Westinghouse--Bettis

  7. Fusion reactor materials

    International Nuclear Information System (INIS)

    1989-01-01

    This paper discuses the following topics on fusion reactor materials: irradiation, facilities, test matrices, and experimental methods; dosimetry, damage parameters, and activation calculations; materials engineering and design requirements; fundamental mechanical behavior; radiation effects; development of structural alloys; solid breeding materials; and ceramics

  8. Optimal Super Dielectric Material

    Science.gov (United States)

    2015-09-01

    plate capacitor will reduce the net field to an unprecedented extent. This family of materials can form materials with dielectric values orders of... Capacitor -Increase Area (A)............8 b. Multi-layer Ceramic Capacitor -Decrease Thickness (d) .......10 c. Super Dielectric Material-Increase...circuit modeling, from [44], and B) SDM capacitor charge and discharge ...................................................22 Figure 15. Dielectric

  9. Raw material versus processing

    International Nuclear Information System (INIS)

    Berg, E.A.T.

    1989-01-01

    Some brazilian aspects related with the obtainment of raw materials for advanced ceramic products are described. The necessity of import raw materials by the advanced ceramic industries is mentioned, generating dangerous depedence for the country. The brazilian mineral reserves for using in raw materials of advanced ceramic are also cited. (C.G.C.) [pt

  10. Chemicals in material cycles

    DEFF Research Database (Denmark)

    Pivnenko, Kostyantyn; Eriksson, Eva; Astrup, Thomas Fruergaard

    2015-01-01

    Material recycling has been found beneficial in terms of resource and energy performance and is greatly promoted throughout the world. A variety of chemicals is used in materials as additives and data on their presence is sparse. The present work dealt with paper as recyclable material and diisob...

  11. Materials science and architecture

    Science.gov (United States)

    Bechthold, Martin; Weaver, James C.

    2017-12-01

    Materiality — the use of various materials in architecture — has been fundamental to the design and construction of buildings, and materials science has traditionally responded to needs formulated by design, engineering and construction professionals. Material properties and processes are shaping buildings and influencing how they perform. The advent of technologies such as digital fabrication, robotics and 3D printing have not only accelerated the development of new construction solutions, but have also led to a renewed interest in materials as a catalyst for novel architectural design. In parallel, materials science has transformed from a field that explains materials to one that designs materials from the bottom up. The conflation of these two trends is giving rise to materials-based design research in which architects, engineers and materials scientists work as partners in the conception of new materials systems and their applications. This Review surveys this development for different material classes (wood, ceramics, metals, concrete, glass, synthetic composites and polymers), with an emphasis on recent trends and innovations.

  12. Cathodoluminescence | Materials Science | NREL

    Science.gov (United States)

    shown on a computer screen; the image of a sample semiconductor material appears as a striated oval material sample shown above; the image is a high-contrast light and dark oval on a dark background and was top left of copper indium gallium selenide semiconductor material sample; the image is shown on a

  13. Strain ageing in welds of nuclear pressure vessels

    International Nuclear Information System (INIS)

    Otterberg, R.; Karlsson, C.

    1979-01-01

    Static and dynamic strain ageing have been investigated on submerged-arc welds and repair welds from plates of the pressure vessel steel A 533B. The results permit the determination of the worst strain ageing conditions existing in a nuclear pressure vessel. Static strain ageing was investigated by means of data from tension tests, hardness measurements and Charpy-V impact properties for prestrained and aged material for ageing temperatures from room temperature to 350 deg C and ageing times up to 1000h. Dynamic strain ageing was investigated by tensile tests up to 350 deg C at different strain rates. At the most static strain ageing was found to increase the impact transition temperature from -75 deg C in the as-received condition to -55 deg C after prestraining and ageing for the plate material, from -35 to -10 deg C for the submerged arc weld and from -90 to -40 deg C for the repair weld. Approximately 10 deg C of the deleterious effect is due to the effect of ageing for the two former materials whereas the corresponding figure for the repair weld amounts to 35 deg C. The dynamic strain ageing is strongest at very low strain rates at temperatures just below 300 deg C. The effect of strain ageing can be reduced by stress relief heat treatment or by other means decreasing the content of nitrogen in solution. (author)

  14. Optimal Aging and Death

    DEFF Research Database (Denmark)

    Dalgaard, Carl-Johan Lars; Strulik, Holger

    2010-01-01

    health investments. At the same time, physiological aspects of the aging process influence optimal savings and health investment. We calibrate the model for the average US male in 2000 and proceed to show that the calibrated model accounts well for the cross-country link between labor productivity......This study introduces physiological aging into a simple model of optimal intertemporal consumption. In this endeavor we draw on the natural science literature on aging. According to the purposed theory, the speed of the aging process and the time of death are endogenously determined by optimal...... and life expectancy in the same year ("the Preston curve"); cross-country income differences can explain differences in life expectancy at age 20 of up to a decade. Moreover, technological change in health care of about 1.1% per year can account for the observed shift in the Preston curve between 1980...

  15. Modulating aging and longevity

    DEFF Research Database (Denmark)

    Rattan, Suresh

    Provides information and an evaluation of a variety of approaches tried for modulating aging and longevity, including dietary supplementation with antioxidants, vitamins and hormones, genetic engineering, life-style alterations, and hormesis through mild stress. After decades of systematic collec....... The goal of research on ageing is not to increase human longevity regardless of the consequences, but to increase active longevity free from disability and functional dependence......Provides information and an evaluation of a variety of approaches tried for modulating aging and longevity, including dietary supplementation with antioxidants, vitamins and hormones, genetic engineering, life-style alterations, and hormesis through mild stress. After decades of systematic...... collection of data describing age-related changes in organisms, organs, tissues, cells and macromolecules, biogerontologists are now in a position to construct general principles of ageing and explore various possibilities of intervention using rational approaches. While not giving serious consideration...

  16. Parylene C Aging Studies.

    Energy Technology Data Exchange (ETDEWEB)

    Achyuthan, Komandoor; Sawyer, Patricia Sue.; Mata, Guillermo Adrian; White II, Gregory Von; Bernstein, Robert

    2014-09-01

    Parylene C is used in a device because of its conformable deposition and other advantages. Techniques to study Parylene C aging were developed, and "lessons learned" that could be utilized for future studies are the result of this initial study. Differential Scanning Calorimetry yielded temperature ranges for Parylene C aging as well as post-deposition treatment. Post-deposition techniques are suggested to improve Parylene C performance. Sample preparation was critical to aging regimen. Short-term (%7E40 days) aging experiments with free standing and ceramic-supported Parylene C films highlighted "lessons learned" which stressed further investigations in order to refine sample preparation (film thickness, single sided uniform coating, machine versus laser cutting, annealing time, temperature) and testing issues ("necking") for robust accelerated aging of Parylene C.

  17. NAD+ in Aging

    DEFF Research Database (Denmark)

    Fang, Evandro F.; Lautrup, Sofie; Hou, Yujun

    2017-01-01

    The coenzyme NAD+ is critical in cellular bioenergetics and adaptive stress responses. Its depletion has emerged as a fundamental feature of aging that may predispose to a wide range of chronic diseases. Maintenance of NAD+ levels is important for cells with high energy demands and for proficient...... neuronal function. NAD+ depletion is detected in major neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases, cardiovascular disease and muscle atrophy. Emerging evidence suggests that NAD+ decrements occur in various tissues during aging, and that physiological and pharmacological...... interventions bolstering cellular NAD+ levels might retard aspects of aging and forestall some age-related diseases. Here, we discuss aspects of NAD+ biosynthesis, together with putative mechanisms of NAD+ action against aging, including recent preclinical and clinical trials. Recent discoveries have...

  18. NEPO cable system aging management programs

    International Nuclear Information System (INIS)

    Toman, G.

    2002-01-01

    through four steps of aging. The change in individual insulated wires and overall cables can be experienced by the user of the training aids allowing plant cables to be assessed to determine if they are like new or have aged significantly and need to be replaced. If large numbers of cables have aged perceptibly, then more sophisticated condition assessment techniques will be needed to discriminate between degrees of aging to allow planning and scheduling of replacements. The program is both evaluating a number of existing techniques to determine their ease of use and accuracy and is developing a totally new technique based on nuclear magnetic resonance testing. The NMR technique is proving to be easy to perform and interpret and can be performed on as little as 1 mg of material. (author)

  19. Tailored Porous Materials

    Energy Technology Data Exchange (ETDEWEB)

    BARTON,THOMAS J.; BULL,LUCY M.; KLEMPERER,WALTER G.; LOY,DOUGLAS A.; MCENANEY,BRIAN; MISONO,MAKOTO; MONSON,PETER A.; PEZ,GUIDO; SCHERER,GEORGE W.; VARTULI,JAMES C.; YAGHI,OMAR M.

    1999-11-09

    Tailoring of porous materials involves not only chemical synthetic techniques for tailoring microscopic properties such as pore size, pore shape, pore connectivity, and pore surface reactivity, but also materials processing techniques for tailoring the meso- and the macroscopic properties of bulk materials in the form of fibers, thin films and monoliths. These issues are addressed in the context of five specific classes of porous materials: oxide molecular sieves, porous coordination solids, porous carbons, sol-gel derived oxides, and porous heteropolyanion salts. Reviews of these specific areas are preceded by a presentation of background material and review of current theoretical approaches to adsorption phenomena. A concluding section outlines current research needs and opportunities.

  20. Fusion Reactor Materials

    International Nuclear Information System (INIS)

    Decreton, M.

    2002-01-01

    The objective of SCK-CEN's programme on fusion reactor materials is to contribute to the knowledge on the radiation-induced behaviour of fusion reactor materials and components as well as to help the international community in building the scientific and technical basis needed for the construction of the future reactor. Ongoing projects include: the study of the mechanical and chemical (corrosion) behaviour of structural materials under neutron irradiation and water coolant environment; the investigation of the characteristics of irradiated first wall material such as beryllium; investigations on the management of materials resulting from the dismantling of fusion reactors including waste disposal. Progress and achievements in these areas in 2001 are discussed

  1. Advances in electronic materials

    CERN Document Server

    Kasper, Erich; Grimmeiss, Hermann G

    2008-01-01

    This special-topic volume, Advances in Electronic Materials, covers various fields of materials research such as silicon, silicon-germanium hetero-structures, high-k materials, III-V semiconductor alloys and organic materials, as well as nano-structures for spintronics and photovoltaics. It begins with a brief summary of the formative years of microelectronics; now the keystone of information technology. The latter remains one of the most important global technologies, and is an extremely complex subject-area. Although electronic materials are primarily associated with computers, the internet

  2. New materials in defence

    International Nuclear Information System (INIS)

    Khan, Sikandar S.; Khan, Shahid A.; Butt, N.M.

    1992-01-01

    National defence is very important and always needs new such materials which have technological and socio-economic development of human society. The types of materials used by a society reflect its level of sophistication. These modern materials are basically the same conventional materials but with a greater knowledge content which include superalloys, modern polymers, engineering ceramics and the advanced composite. The production and use of new materials is playing and important role in the recent development in the defence industry. (A.B.)

  3. Advanced Industrial Materials Program

    Science.gov (United States)

    Stooksbury, F.

    1994-06-01

    The mission of the Advanced Industrial Materials (AIM) program is to commercialize new/improved materials and materials processing methods that will improve energy efficiency, productivity, and competitiveness. Program investigators in the DOE national laboratories are working with about 100 companies, including 15 partners in CRDA's. Work is being done on intermetallic alloys, ceramic composites, metal composites, polymers, engineered porous materials, and surface modification. The program supports other efforts in the Office of Industrial Technologies to assist the energy-consuming process industries. The aim of the AIM program is to bring materials from basic research to industrial application to strengthen the competitive position of US industry and save energy.

  4. Methods of materiality

    DEFF Research Database (Denmark)

    Aagaard, Jesper; Matthiesen, Noomi Christine Linde

    2016-01-01

    that researchers should start paying attention to the material world (consisting of both human bodies and material objects) and what it means for how people live their lives. It is argued that this can be done by incorporating the concept of material presence to capture embodied and material layers of existence......This article challenges the hegemonic status of “language” as the primary substance of qualitative research in psychology, whether through interviews or recordings of naturally occurring talk. It thereby questions the overt focus on analyzing linguistic “meaning.” Instead, it is suggested...... practical guidelines for incorporating attention to materiality in qualitative research....

  5. Hybrid sol-gel optical materials

    Science.gov (United States)

    Zeigler, John M.

    1992-01-01

    Hybrid sol-gel materials comprise silicate sols cross-linked with linear polysilane, polygermane, or poly(silane-germane). The sol-gel materials are useful as optical identifiers in tagging and verification applications and, in a different aspect, as stable, visible light transparent non-linear optical materials. Methyl or phenyl silicones, polyaryl sulfides, polyaryl ethers, and rubbery polysilanes may be used in addition to the linear polysilane. The linear polymers cross-link with the sol to form a matrix having high optical transparency, resistance to thermooxidative aging, adherence to a variety of substrates, brittleness, and a resistance to cracking during thermal cycling.

  6. Annual review of materials science. Volume 7

    International Nuclear Information System (INIS)

    Huggins, R.A.; Bube, R.H.; Roberts, R.W.

    1977-01-01

    A review is presented of recent materials science research. Topics covered include: point defects and their interaction; defect chemistry in crystalline solids; deep level impurities in semiconductors; structural aspects of one-dimensional conductors; structural transformations during aging of metal alloys; high rate thick film growth; metal forming, the application of limit analysis; kinetics and mechanisms of gas-metal interactions; erosion; reversible temper embrittlement; acoustic emission in brittle materials; capacitance transient spectroscopy; hot corrosion of high-temperature alloys; fundamental optical phenomena in infrared window materials; dental amalgam; and transparent conducting coatings

  7. Modelling of thermoelectric materials

    DEFF Research Database (Denmark)

    Bjerg, Lasse

    In order to discover new good thermoelectric materials, there are essentially two ways. One way is to go to the laboratory, synthesise a new material, and measure the thermoelectric properties. The amount of compounds, which can be investigated this way is limited because the process is time...... consuming. Another approach is to model the thermoelectric properties of a material on a computer. Several crystal structures can be investigated this way without use of much man power. I have chosen the latter approach. Using density functional theory I am able to calculate the band structure of a material....... This band structure I can then use to calculate the thermoelectric properties of the material. With these results I have investigated several materials and found the optimum theoretical doping concentration. If materials with these doping concentrations be synthesised, considerably better thermoelectric...

  8. IAEA biological reference materials

    International Nuclear Information System (INIS)

    Parr, R.M.; Schelenz, R.; Ballestra, S.

    1988-01-01

    The Analytical Quality Control Services programme of the IAEA encompasses a wide variety of intercomparisons and reference materials. This paper reviews only those aspects of the subject having to do with biological reference materials. The 1988 programme foresees 13 new intercomparison exercises, one for major, minor and trace elements, five for radionuclides, and seven for stable isotopes. Twenty-two natural matrix biological reference materials are available: twelve for major, minor and trace elements, six for radionuclides, and four for chlorinated hydrocarbons. Seven new intercomparisons and reference materials are in preparation or under active consideration. Guidelines on the correct use of reference materials are being prepared for publication in 1989 in consultation with other major international producers and users of biological reference materials. The IAEA database on available reference materials is being updated and expanded in scope, and a new publication is planned for 1989. (orig.)

  9. Articulating Material Criteria

    DEFF Research Database (Denmark)

    Hasling, Karen Marie

    2013-01-01

    , imitate and articulate the students’ inclusion of materials. This paper particularly discusses the experiences made and ideas generated after the execution of a material science course for second year students, with emphasis on the concept of the material selection matrix as an educational tool......This paper discusses the experiences and potentials with materials teaching at the Institute for Product Design at Kolding School of Design, using materials teaching as experiments in my PhD project. The project intents to create a stronger material awareness among product design students...... with emphasis on sustainability. The experiments aim to develop an understanding of, how product design students include materials in their design practice and how tools can be developed that further enhance this. Hence experiments are essential for the progress of the PhD project as they help to observe...

  10. Contact materials for nanoelectronics

    KAUST Repository

    Alshareef, Husam N.

    2011-02-01

    In this article, we review current research activities in contact material development for electronic and nanoelectronic devices. A fundamental issue in contact materials research is to understand and control interfacial reactions and phenomena that modify the expected device performance. These reactions have become more challenging and more difficult to control as new materials have been introduced and as device sizes have entered the deep nanoscale. To provide an overview of this field of inquiry, this issue of MRS Bulletin includes articles on gate and contact materials for Si-based devices, junction contact materials for Si-based devices, and contact materials for alternate channel substrates (Ge and III-V), nanodevices. © 2011 Materials Research Society.

  11. Comprehensive hard materials

    CERN Document Server

    2014-01-01

    Comprehensive Hard Materials deals with the production, uses and properties of the carbides, nitrides and borides of these metals and those of titanium, as well as tools of ceramics, the superhard boron nitrides and diamond and related compounds. Articles include the technologies of powder production (including their precursor materials), milling, granulation, cold and hot compaction, sintering, hot isostatic pressing, hot-pressing, injection moulding, as well as on the coating technologies for refractory metals, hard metals and hard materials. The characterization, testing, quality assurance and applications are also covered. Comprehensive Hard Materials provides meaningful insights on materials at the leading edge of technology. It aids continued research and development of these materials and as such it is a critical information resource to academics and industry professionals facing the technological challenges of the future. Hard materials operate at the leading edge of technology, and continued res...

  12. Multicomponent polymeric materials

    CERN Document Server

    Thomas, Sabu; Saha, Prosenjit

    2016-01-01

    The book offers an in-depth review of the materials design and manufacturing processes employed in the development of multi-component or multiphase polymer material systems. This field has seen rapid growth in both academic and industrial research, as multiphase materials are increasingly replacing traditional single-component materials in commercial applications. Many obstacles can be overcome by processing and using multiphase materials in automobile, construction, aerospace, food processing, and other chemical industry applications. The comprehensive description of the processing, characterization, and application of multiphase materials presented in this book offers a world of new ideas and potential technological advantages for academics, researchers, students, and industrial manufacturers from diverse fields including rubber engineering, polymer chemistry, materials processing and chemical science. From the commercial point of view it will be of great value to those involved in processing, optimizing an...

  13. Matter and materials

    International Nuclear Information System (INIS)

    Lefevre, J.

    1997-01-01

    This paper is an introduction to the materials used in nuclear engineering from the uranium (extraction, processing, ultimate use) to all radioactive products encountered in nuclear processes and more particularly those having particular applications or presenting particular risks in their ultimate disposal. This introduction gives a general presentation of the different topics which are developed in other chapters: nuclear materials and fuel cycle (fuel fabrication, actinides and recycling, direct storage and reprocessing of spent fuels, management of radioactive wastes, transport of radioactive materials, production and use of radioelements in the industry and medicine), moderators and coolants, other materials used in reactors (fuel cladding materials, special steels, zircaloy, neutron absorbent materials), and the mechanical behaviour of materials (steels, concretes). (J.S.)

  14. Superconductors and electrotechnical materials

    Energy Technology Data Exchange (ETDEWEB)

    Stanculescu, V

    1975-07-01

    A description is given of the properties of superconducting materials and of other materials which will be used in low temperature electrical engineering. The electrical and magnetic properties of type 1 or soft and type 2 or hard superconducting materials are analyzed. Electroinsulating and magnetic materials at low temperatures are also surveyed. Emphasis is placed on gaseous and fluid dielectric substances which retain their condition of physical aggregation at low temperatures and provide a cryogenic medium. These include helium, hydrogen, and nitrogen. As for solid dielectrics, satisfactory electroinsulating materials in terms of mechanical and electrical properties include the category of thermoplastic organic materials such as mylar, teflon, kapton, and nylon. It is also emphasized that cryoelectrical engineering requires magnetic materials with high magnetic induction at low temperatures, coercive field and low magnetic loss.

  15. Comprehensive nuclear materials

    CERN Document Server

    Allen, Todd; Stoller, Roger; Yamanaka, Shinsuke

    2012-01-01

    Comprehensive Nuclear Materials encapsulates a panorama of fundamental information on the vast variety of materials employed in the broad field of nuclear technology. The work addresses, in five volumes, 3,400 pages and over 120 chapter-length articles, the full panorama of historical and contemporary international research in nuclear materials, from Actinides to Zirconium alloys, from the worlds' leading scientists and engineers. It synthesizes the most pertinent research to support the selection, assessment, validation and engineering of materials in extreme nuclear environments. The work discusses the major classes of materials suitable for usage in nuclear fission, fusion reactors and high power accelerators, and for diverse functions in fuels, cladding, moderator and control materials, structural, functional, and waste materials.

  16. Frailty Across Age Groups.

    Science.gov (United States)

    Pérez-Zepeda, M U; Ávila-Funes, J A; Gutiérrez-Robledo, L M; García-Peña, C

    2016-01-01

    The implementation of an aging biomarker into clinical practice is under debate. The Frailty Index is a model of deficit accumulation and has shown to accurately capture frailty in older adults, thus bridging biological with clinical practice. To describe the association of socio-demographic characteristics and the Frailty Index in different age groups (from 20 to over one hundred years) in a representative sample of Mexican subjects. Cross-sectional analysis. Nationwide and population-representative survey. Adults 20-years and older interviewed during the last Mexican National Health and Nutrition Survey (2012). A 30-item Frailty Index following standard construction was developed. Multi-level regression models were performed to test the associations of the Frailty Index with multiple socio-demographic characteristics across age groups. A total of 29,504 subjects was analyzed. The 30-item Frailty Index showed the highest scores in the older age groups, especially in women. No sociodemographic variable was associated with the Frailty Index in all the studied age groups. However, employment, economic income, and smoking status were more consistently found across age groups. To our knowledge, this is the first report describing the Frailty Index in a representative large sample of a Latin American country. Increasing age and gender were closely associated with a higher score.

  17. Probabilistic population aging

    Science.gov (United States)

    2017-01-01

    We merge two methodologies, prospective measures of population aging and probabilistic population forecasts. We compare the speed of change and variability in forecasts of the old age dependency ratio and the prospective old age dependency ratio as well as the same comparison for the median age and the prospective median age. While conventional measures of population aging are computed on the basis of the number of years people have already lived, prospective measures are computed also taking account of the expected number of years they have left to live. Those remaining life expectancies change over time and differ from place to place. We compare the probabilistic distributions of the conventional and prospective measures using examples from China, Germany, Iran, and the United States. The changes over time and the variability of the prospective indicators are smaller than those that are observed in the conventional ones. A wide variety of new results emerge from the combination of methodologies. For example, for Germany, Iran, and the United States the likelihood that the prospective median age of the population in 2098 will be lower than it is today is close to 100 percent. PMID:28636675

  18. Biological materials: a materials science approach.

    Science.gov (United States)

    Meyers, Marc A; Chen, Po-Yu; Lopez, Maria I; Seki, Yasuaki; Lin, Albert Y M

    2011-07-01

    The approach used by Materials Science and Engineering is revealing new aspects in the structure and properties of biological materials. The integration of advanced characterization, mechanical testing, and modeling methods can rationalize heretofore unexplained aspects of these structures. As an illustration of the power of this methodology, we apply it to biomineralized shells, avian beaks and feathers, and fish scales. We also present a few selected bioinspired applications: Velcro, an Al2O3-PMMA composite inspired by the abalone shell, and synthetic attachment devices inspired by gecko. Copyright © 2010 Elsevier Ltd. All rights reserved.

  19. Age Discrimination and the FAA Age 60 Rule. Hearing before the Select Committee on Aging. House of Representatives, Ninety-Ninth Congress, First Session.

    Science.gov (United States)

    Congress of the U.S., Washington, DC. House Select Committee on Aging.

    This document presents witness testimonies and related materials from a Congressional hearing called to examine the mandatory retirement age of 60 for airline pilots. In opening remarks, Congressmen Roybal and Pepper question this ruling, citing productivity of older workers and the lack of data to support any specific age for mandatory…

  20. Aging in Colombia

    Directory of Open Access Journals (Sweden)

    María Lourdes SANTOS PÉREZ

    2015-12-01

    Full Text Available Using data from statistical sources and official reports, we propose a critical approach to aging in Colombia, specifically from the point of view of public policy in progress or in planning. Our main hypothesis is that these measures refuse comprehensive treatment of the ageing in terms of needs and rights promoting a pure welfare system which, instead, contributes to reinforce a collective imagination of a dependent and impoverished old age, with «fatal» consequences that sustain and reproduce the socioeconomic system.