WorldWideScience

Sample records for impact limiter material

  1. Limits on methane release and generation via hypervelocity impact of Martian analogue materials

    Science.gov (United States)

    Price, M. C.; Ramkissoon, N. K.; McMahon, S.; Miljković, K.; Parnell, J.; Wozniakiewicz, P. J.; Kearsley, A. T.; Blamey, N. J. F.; Cole, M. J.; Burchell, M. J.

    2014-04-01

    The quantity of methane in Mars' atmosphere, and the potential mechanism(s) responsible for its production, are still unknown. In order to test viable, abiotic, methangenic processes, we experimentally investigated two possible impact mechanisms for generating methane. In the first suite of experiments, basaltic rocks were impacted at 5 km s-1 and the quantity of gases (CH4, H2, He, N2, O2, Ar and CO2) released by the impacts was measured. In the second suite of experiments, a mixture of water ice, CO2 ice and anhydrous olivine grains was impacted to see if the shock induced rapid serpentinization of the olivine, and thus production of methane. The results of both suites of experiments demonstrate that impacts (at scales achievable in the laboratory) do not give rise to detectably enhanced quantities of methane release above background levels. Supporting hydrocode modelling was also performed to gain insight into the pressures and temperatures occurring during the impact events.

  2. Development of a impact limiter for radioactive material transport packages - characterization of the polymeric material used; Desenvolvimento de amortecedor de impacto para embalagens para transporte de material radioativo - caracterizacao do material polimerico utilizado

    Energy Technology Data Exchange (ETDEWEB)

    Mourao, Rogerio Pimenta [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil)]. E-mail: mouraor@urano.cdtn.br; Mattar Neto, Miguel [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: mmattar@net.ipen.br

    2000-07-01

    Impact limiters are sacrificial components widely used to protect radioactive waste packages against damages arising from falls, fires and collisions with protruding objects. Several materials have been used as impact limiter filling: wood, aluminum honeycomb, and metallic or polymeric foams. Besides, hollow structures are also used as shock absorbers, either as a single shell or as a tube array. One of the most popular materials among package designers is rigid polyurethane foam, owing to its toughness, workability, low specific weight, low costs and commercial availability. In Brazil, a foam developed using the polymer extracted from the castor oil plant (Ricinus communis) is being studied as a potential impact limiter filling. For a better performance of this material, it is necessary to minimize the impact limiter dimensions without compromising the package safety. For this, a detailed knowledge of the foam physical and mechanical properties is essential. A relatively vast amount of data about regular polymeric foams can be found in the literature and in foreign manufacturers brochures, but no data has been published about the properties of the castor oil foam. This paper presents data gathered in an ongoing research program aiming at the development of a Type-B packaging. Foam samples were submitted to uniaxial static compression tests and to hydrostatic tests. The results obtained reveal that the castor oil foam has a mechanical behavior similar to that of regular foams, with good property reproducibility and homogeneity. (author)

  3. Aluminum honeycomb impact limiter study

    Energy Technology Data Exchange (ETDEWEB)

    Yaksh, M.C.; Thompson, T.C. (Nuclear Assurance Corp., Norcross, GA (United States)); Nickell, R.E. (Applied Science and Technology, Inc., Poway, CA (United States))

    1991-07-01

    Design requirements for a cask transporting radioactive materials must include the condition of the 30-foot free fall of the cask onto an unyielding surface. To reduce the deceleration loads to a tolerable level for all the components of the cask, a component (impact limiter) is designed to absorb the kinetic energy. The material, shape, and method of attachment of the impact limiter to the cask body comprises the design of the impact limiter. The impact limiter material of interest is honeycomb aluminum, and the particular design examined was for the NAC Legal Weight Truck cask (NAC-LWT) for spent fuel from light water reactors. The NAC-LWT has a design weight of 52,000 pounds, and it has a nominal length of 200 inches. The report describes the numerical calculations embodied in the FADE program to determine the accelerations and crush strain resulting from an arbitrary height and angle of orientation. Since the program serves as a design tool, static tests are performed to assess the effect of the shell containing the honeycomb aluminum. The static tests and their results are contained in the study. The static tests are used to demonstrate for licensing purposes the level of accelerations imposed on the cask during a 30-foot drop. 3 refs., 41 figs., 15 tabs.

  4. Impact limiters for radioactive materials transport packagings: a methodology for assessment; Amortecedores de impacto em embalagens para transporte de materiais radioativos: uma metodologia para sua avaliacao

    Energy Technology Data Exchange (ETDEWEB)

    Mourao, Rogerio Pimenta

    2002-07-01

    This work aims at establishing a methodology for design assessment of a cellular material-filled impact limiter to be used as part of a radioactive material transport packaging. This methodology comprises the selection of the cellular material, its structural characterization by mechanical tests, the development of a case study in the nuclear field, preliminary determination of the best cellular material density for the case study, performance of the case and its numerical simulation using the finite element method. Among the several materials used as shock absorbers in packagings, the polyurethane foam was chosen, particularly the foam obtained from the castor oil plant (Ricinus communis), a non-polluting and renewable source. The case study carried out was the 9 m drop test of a package prototype containing radioactive wastes incorporated in a cement matrix, considered one of the most severe tests prescribed by the Brazilian and international transport standards. Prototypes with foam density pre-determined as ideal as well as prototypes using lighter and heavier foams were tested for comparison. The results obtained validate the methodology in that expectations regarding the ideal foam density were confirmed by the drop tests and the numerical simulation. (author)

  5. Investigation of the behaviour of impact limiting devices of transport casks for radioactive materials in the package approval and risk analysis; Untersuchung des Verhaltens stossdaempfender Bauteile von Transportbehaeltern fuer radioaktive Stoffe in Bauartpruefung und Risikoanalyse

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, Martin

    2009-08-20

    Transport casks for radioactive materials with a Type-B package certificate have to ensure that even under severe accident scenarios the radioactive content remains safely enclosed, in an undercritical arrangement and that ionising radiation is sufficiently shielded. The impact limiter absorbs in an accident scenario the major part of the impact energy and reduces the maximum force applied on the cask body. Therefore the simulation of the behaviour of impact limiting devices of transport casks for nuclear material is of great interest for the design assessment in the package approval as well as for risk analysis in the field of transport of radioactive materials. The behaviour of the impact limiter is influenced by a number of parameters like impact limiter construction, material properties and loading conditions. Uncertainties exist for the application of simplified numerical tools for calculations of impact limiting devices. Uncertainities exist when applying simplified numerical tools. A model describing the compression of wood in axial direction of wood under large deformations for simulation with complex numerical procedures like dynamic Finite Element Methods has not been developed yet. Therefore this thesis concentrates on deriving a physical model for the behaviour of wood and analysing the applicability of different modeling techniques. A model describing the compression of wood in axial direction under large deformations was developed on the basis of an analysis of impact limiter of prototypes of casks for radioactive materials after a 9-m-drop-test and impact tests with wooden specimens. The model describes the softening, which wood under large deformation exhibits, as a function of the lateral strain constraint. The larger the lateral strain restriction, the more energy wood can absorb. The energy absorption capacity of impact limiter depends therefore on the ability of the outer steel sheet structure to prevent wood from evading from the main

  6. Material Limitations on the Detection Limit in Refractometry

    OpenAIRE

    Niels Asger Mortensen; Sanshui Xiao; Peder Skafte-Pedersen; Nunes, Pedro S.

    2009-01-01

    We discuss the detection limit for refractometric sensors relying on high-Q optical cavities and show that the ultimate classical detection limit is given by min {Δn} ≳ η, with n + iη being the complex refractive index of the material under refractometric investigation. Taking finite Q factors and filling fractions into account, the detection limit declines. As an example we discuss the fundamental limits of silicon-based high-Q resonators, such as photonic crystal resonators, for sensing in ...

  7. Material limitations on the detection limit in refractometry.

    Science.gov (United States)

    Skafte-Pedersen, Peder; Nunes, Pedro S; Xiao, Sanshui; Mortensen, Niels Asger

    2009-01-01

    We discuss the detection limit for refractometric sensors relying on high-Q optical cavities and show that the ultimate classical detection limit is given by min {Δn} ≳ η, with n + iη being the complex refractive index of the material under refractometric investigation. Taking finite Q factors and filling fractions into account, the detection limit declines. As an example we discuss the fundamental limits of silicon-based high-Q resonators, such as photonic crystal resonators, for sensing in a bio-liquid environment, such as a water buffer. In the transparency window (λ ≳ 1100 nm) of silicon the detection limit becomes almost independent on the filling fraction, while in the visible, the detection limit depends strongly on the filling fraction because the silicon absorbs strongly.

  8. Material Limitations on the Detection Limit in Refractometry

    CERN Document Server

    Skafte-Pedersen, Peder; Xiao, Sanshui; Mortensen, Niels Asger; 10.3390/s91108382

    2009-01-01

    We discuss the detection limit for refractometric sensors relying on high-Q optical cavities and show that the ultimate classical detection limit is given by min{Dn} > eta with n+i*eta being the complex refractive index of the material under refractometric investigation. Taking finite Q factors and filling fractions into account, the detection limit declines. As an example we discuss the fundamental limits of silicon-based high-Q resonators, such as photonic crystal resonators, for sensing in a bio-liquid environment, such as a water buffer. In the transparency window of silicon the detection limit becomes almost independent on the filling fraction, while in the visible, the detection limit depends strongly on the filling fraction because silicon absorbs strongly.

  9. Material Limitations on the Detection Limit in Refractometry

    Directory of Open Access Journals (Sweden)

    Niels Asger Mortensen

    2009-10-01

    Full Text Available We discuss the detection limit for refractometric sensors relying on high-Q optical cavities and show that the ultimate classical detection limit is given by min {Δn} ≳ η with n + iη being the complex refractive index of the material under refractometric investigation. Taking finite Q factors and filling fractions into account, the detection limit declines. As an example we discuss the fundamental limits of silicon-based high-Q resonators, such as photonic crystal resonators, for sensing in a bio-liquid environment, such as a water buffer. In the transparency window (λ ≳ 1100 nm of silicon the detection limit becomes almost independent on the filling fraction, while in the visible, the detection limit depends strongly on the filling fraction because the silicon absorbs strongly.

  10. Material limitations on the detection limit in refractometry

    DEFF Research Database (Denmark)

    Skafte-Pedersen, Peder; Nunes, Pedro; Xiao, Sanshui

    2009-01-01

    We discuss the detection limit for refractometric sensors relying on high-Q optical cavities and show that the ultimate classical detection limit is given by min {Δn} ≳ η with n + iη being the complex refractive index of the material under refractometric investigation. Taking finite Q factors...... and filling fractions into account, the detection limit declines. As an example we discuss the fundamental limits of silicon-based high-Q resonators, such as photonic crystal resonators, for sensing in a bio-liquid environment, such as a water buffer. In the transparency window (λ ≳ 1100 nm) of silicon...... the detection limit becomes almost independent on the filling fraction, while in the visible, the detection limit depends strongly on the filling fraction because the silicon absorbs strongly....

  11. Investigation of the behaviour of impact limiting devices of transport casks for radioactive materials in the package approval and risk analysis; Untersuchung des Verhaltens stossdaempfender Bauteile von Transportbehaeltern fuer radioaktive Stoffe in Bauartpruefung und Risikoanalyse

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, Martin

    2009-08-20

    Transport casks for radioactive materials with a Type-B package certificate have to ensure that even under severe accident scenarios the radioactive content remains safely enclosed, in an undercritical arrangement and that ionising radiation is sufficiently shielded. The impact limiter absorbs in an accident scenario the major part of the impact energy and reduces the maximum force applied on the cask body. Therefore the simulation of the behaviour of impact limiting devices of transport casks for nuclear material is of great interest for the design assessment in the package approval as well as for risk analysis in the field of transport of radioactive materials. The behaviour of the impact limiter is influenced by a number of parameters like impact limiter construction, material properties and loading conditions. Uncertainties exist for the application of simplified numerical tools for calculations of impact limiting devices. Uncertainities exist when applying simplified numerical tools. A model describing the compression of wood in axial direction of wood under large deformations for simulation with complex numerical procedures like dynamic Finite Element Methods has not been developed yet. Therefore this thesis concentrates on deriving a physical model for the behaviour of wood and analysing the applicability of different modeling techniques. A model describing the compression of wood in axial direction under large deformations was developed on the basis of an analysis of impact limiter of prototypes of casks for radioactive materials after a 9-m-drop-test and impact tests with wooden specimens. The model describes the softening, which wood under large deformation exhibits, as a function of the lateral strain constraint. The larger the lateral strain restriction, the more energy wood can absorb. The energy absorption capacity of impact limiter depends therefore on the ability of the outer steel sheet structure to prevent wood from evading from the main

  12. Selected Parametric Effects on Materials Flammability Limits

    Science.gov (United States)

    Hirsch, David B.; Juarez, Alfredo; Peyton, Gary J.; Harper, Susana A.; Olson, Sandra L.

    2011-01-01

    NASA-STD-(I)-6001B Test 1 is currently used to evaluate the flammability of materials intended for use in habitable environments of U.S. spacecraft. The method is a pass/fail upward flame propagation test conducted in the worst case configuration, which is defined as a combination of a material s thickness, test pressure, oxygen concentration, and temperature that make the material most flammable. Although simple parametric effects may be intuitive (such as increasing oxygen concentrations resulting in increased flammability), combinations of multi-parameter effects could be more complex. In addition, there are a variety of material configurations used in spacecraft. Such configurations could include, for example, exposed free edges where fire propagation may be different when compared to configurations commonly employed in standard testing. Studies involving combined oxygen concentration, pressure, and temperature on flammability limits have been conducted and are summarized in this paper. Additional effects on flammability limits of a material s thickness, mode of ignition, burn-length criteria, and exposed edges are presented. The information obtained will allow proper selection of ground flammability test conditions, support further studies comparing flammability in 1-g with microgravity and reduced gravity environments, and contribute to persuasive scientific cases for rigorous space system fire risk assessments.

  13. LimitS - A system for limit state analysis and optimal material layout

    DEFF Research Database (Denmark)

    Damkilde, Lars; Krenk, Steen

    1997-01-01

    A system LimitS for limit state analysis and material optimization has been developed and implemented in a PC environment. The program is formulated in a general finite element format with stress-based elements. The solution method is based on the lower-bound theorem, where an optimal stress...... the statics and kinematics of the collapse mode are determined via the dual variables of the LP-problem. In LimitS the following element types are implemented: two- and three-dimensional beam elements; truss elements; triangular slab elements; and shear and stringer elements for plates with in-plane loading....... Examples of all three problem types are given including both limit state analysis and material optimization....

  14. LimitS - A system for limit state analysis and optimal material layout

    DEFF Research Database (Denmark)

    Damkilde, Lars; Krenk, Steen

    1997-01-01

    A system LimitS for limit state analysis and material optimization has been developed and implemented in a PC environment. The program is formulated in a general finite element format with stress-based elements. The solution method is based on the lower-bound theorem, where an optimal stress...... the statics and kinematics of the collapse mode are determined via the dual variables of the LP-problem. In LimitS the following element types are implemented: two- and three-dimensional beam elements; truss elements; triangular slab elements; and shear and stringer elements for plates with in-plane loading....... Examples of all three problem types are given including both limit state analysis and material optimization....

  15. Optical Limiting Materials Based on Gold Nanoparticles

    Science.gov (United States)

    2014-04-30

    Murphy, University of Illinois at Urbana-Champaign (formerly University of South Carolina), Department of Chemistry Award Number: FA9550-09-1-0246...of the electromagnetic spectrum. 2. Functionalization of the surface of the gold nanoparticles with selected organic and inorganic materials, with...the thesis work of one Ph.D. student (Sean Sivapalan, Ph.D. in materials science and engineering, graduated in 2013, now employed at Intel

  16. Limiting our impact on the environment

    CERN Multimedia

    2012-01-01

    CERN’s fourth safety objective for 2012 concerns the reduction of the environmental impact of noise and energy consumption associated with CERN's activities.   In order to continue to reduce the impact of noise on our neighbours, the HSE Unit is coordinating measures to reduce noise in the environment at all the LHC and SPS points, and on the Meyrin and Prévessin sites. If you are aware of a high-intensity noise that could disturb those living and working close to our sites, you can contact the HSE Unit. And most important of all, please take this potential nuisance into account when you're planning new projects. The HSE Unit is there to help you. The other aspect of our environmental target for the year is to optimise CERN's energy consumption. We can achieve this by limiting the energy consumption of facilities right from the design stage - from small components to large installations - and by using renewable energies even on a sma...

  17. Limiting the current with HTc materials; HTc pour la limitation du courant

    Energy Technology Data Exchange (ETDEWEB)

    Barbut, J.M.; Belmont, O.; Devismes, M.F.; Noudem, J.G.; Porcar, L.; Sanchez, J. [Schneider Electric, Grenoble (France); Tixador, P. [CRTBT, CNRS, Grenoble (France); Bourgault, D.; Tournier, R. [Matformag, CNRS, Grenoble (France)

    1998-01-01

    Superconducting fault current limiter could be used in high voltage network. A most part of existing HTc superconducting materials have been tested in situation to limit fault current. Bulk materials are classified by growing critical current density which correspond to different behaviours. Critical electrical field during transition seems to be about 1 kV/m. (orig.). 7 refs.

  18. Doublet III limiter performance and implications for mechanical design and material selection for future limiters

    Energy Technology Data Exchange (ETDEWEB)

    Sabado, M.M.; Marcus, F.B.; Trester, P.W.; Wesley, J.C.

    1979-10-01

    The plasma limiter system for Doublet III is described. Initially, high-Z materials, Ta-10W for the primary limiter and Mo for the backup limiters, were selected as the most attractive metallic candidates from the standpoint of thermal and structural properties. For the purpose of evaluating the effect of material Z on plasma performance, the nonmagnetic, Ni-base alloy Inconel X-750 was selected for a medium-Z limiter material. Graphite, a low-Z material, will likely be the next limiter material for evaluation. Design and material selection criteria for the different Z ranges are presented. The performance of the high-Z limiters in Doublet III is reviewed for an operation period that included approximately 5000 plasma shots. Changes in surface appearance and metallurgical changes are characterized. Discussion is presented on how and to what extent the high-Z elements affected the performance of the plasma based on theory and measurements in Doublet III. The fabrication processes for the Inconel X-750 limiters are summarized, and, last, observations on early performance of the Inconel limiters are described. (MOW)

  19. IMPACT CONICAL ROD ON HARD LIMITER

    Directory of Open Access Journals (Sweden)

    Ulitin G.

    2014-12-01

    Full Text Available The problem is considered of longitudinal impact conical rod in article. A recommendation on the use of the approximate method of calculation is based on an analysis of the influence of design parameters on the value of the main oscillation frequency. There was obtained an equation of the displacement and stress of the rod. Engineering dependence has been proposed to determine the maximum force in the impact section.

  20. IMPACT GRINDING OF DAMP MATERIALS

    Directory of Open Access Journals (Sweden)

    Ladaev Nikolay Mikhaylovich

    2012-10-01

    Centrifugal grinders were used to analyze the grinding process. The experimental data have proven that the probability of destruction of damp samples is a lot higher than the one of dry samples, given the same initial dimensions of particles and the loading intensity. The rise in the probability of destruction is stipulated by the fact that that the grinder speed at which crushing is triggered is lower in case of damp samples than in case of dry ones. Expressions for speed that describes destruction initiation and the probability of destruction depending on the type of materials, the moisture content and the loading intensity have been derived.

  1. Direct methods for limit states in structures and materials

    CERN Document Server

    Weichert, Dieter

    2014-01-01

    Knowing the safety factor for limit states such as plastic collapse, low cycle fatigue or ratcheting is always a major design consideration for civil and mechanical engineering structures that are subjected to loads. Direct methods of limit or shakedown analysis that proceed to directly find the limit states offer a better alternative than exact time-stepping calculations as, on one hand, an exact loading history is scarcely known, and on the other they are much less time-consuming. This book presents the state of the art on various topics concerning these methods, such as theoretical advances in limit and shakedown analysis, the development of relevant algorithms and computational procedures, sophisticated modeling of inelastic material behavior like hardening, non-associated flow rules, material damage and fatigue, contact and friction, homogenization and composites.

  2. Carbon nanotube-based functional materials for optical limiting.

    Science.gov (United States)

    Chen, Yu; Lin, Ying; Liu, Ying; Doyle, James; He, Nan; Zhuang, Xiaodong; Bai, Jinrui; Blau, Werner J

    2007-01-01

    Optical limiting is an important application of nonlinear optics, useful for the protection of human eyes, optical elements, and optical sensors from intense laser pulses. An optical limiter is such a device that strongly attenuates high intensity light and potentially damaging light such as focused laser beams, whilst allowing for the high transmission of ambient light. Optical limiting properties of carbon nanotube suspensions, solubilized carbon nanotubes, small molecules doped carbon nanotubes and polymer/carbon nanotube composites have been reviewed. The optical limiting responses of carbon nanotube suspensions are shown to be dominated by nonlinear scattering as a result of thermally induced solvent-bubble formation and sublimation of the nanotubes, while the solubilized carbon nanotubes optically limit through nonlinear absorption mechanism and exhibit significant solution-concentration-dependent optical limiting responses. In the former case the optical limiting results are independent of nanotube concentrations at the same linear transmittance as that of the solubilized systems. Many efforts have been invested into the research of polymer/carbon nanotube composites in an attempt to allow for the fabrication of films required for the use of nanotubes in a real optical limiting application. The higher carbon nanotube content samples block the incident light more effectively at higher incident energy densities or intensities. The optical limiting mechanism of these composite materials is quite complicated. Besides nonlinear scattering contribution to the optical limiting, there may also be other contributions e.g., nonlinear absorption, nonlinear refraction, electronic absorption and others to the optical limiting. Further improvements in the optical limiting efficiency of the composites and in the dispersion and alignment properties of carbon nanotubes in the polymer matrix could be realized by variation of both nanostructured guest and polymer host, and by

  3. Materials and structures under shock and impact

    CERN Document Server

    Bailly, Patrice

    2013-01-01

    In risk studies, engineers often have to consider the consequences of an accident leading to a shock on a construction. This can concern the impact of a ground vehicle or aircraft, or the effects of an explosion on an industrial site.This book presents a didactic approach starting with the theoretical elements of the mechanics of materials and structures, in order to develop their applications in the cases of shocks and impacts. The latter are studied on a local scale at first. They lead to stresses and strains in the form of waves propagating through the material, this movement then extending

  4. Waste material recycling: Assessment of contaminants limiting recycling

    DEFF Research Database (Denmark)

    Pivnenko, Kostyantyn

    systematically investigated. This PhD project provided detailed quantitative data following a consistent approach to assess potential limitations for the presence of chemicals in relation to material recycling. Paper and plastics were used as illustrative examples of materials with well-established recycling...... schemes and great potential for increase in recycling, respectively. The approach followed in the present work was developed and performed in four distinct steps. As step one, fractional composition of waste paper (30 fractions) and plastics (9 fractions) from households in Åbenrå municipality (Southern...... recycling has been recognised as a backbone of circular economy, with constant measures and initiatives being proposed in order to increase the recycling rates of materials being consumed. Material cycles are complex and dynamic systems where chemicals are added and removed in production, manufacturing...

  5. Microscopic Investigation of Materials Limitations of Superconducting RF Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Anlage, Steven [Univ. of Maryland, College Park, MD (United States)

    2017-08-04

    Our overall goal is to contribute to the understanding of defects that limit the high accelerating gradient performance of Nb SRF cavities. Our approach is to develop a microscopic connection between materials defects and SRF performance. We developed a near-field microwave microscope to establish this connection. The microscope is based on magnetic hard drive write heads, which are designed to create very strong rf magnetic fields in very small volumes on a surface.

  6. Mass of materials: the impact of designers on construction ergonomics.

    Science.gov (United States)

    Smallwood, John

    2012-01-01

    Many construction injuries are musculoskeletal related in the form of sprains and strains arising from the handling of materials, which are specified by designers. The paper presents the results of a study conducted among delegates attending two 'designing for H&S' (DfH&S) seminars using a questionnaire. The salient findings include: the level of knowledge relative to the mass and density of materials is limited; designers generally do not consider the mass and density of materials when designing structures and elements and specifying materials; to a degree designers appreciate that the mass and density of materials impact on construction ergonomics; designers rate their knowledge of the mass and density of materials as limited, and designers appreciate the potential of the consideration of the mass and density of materials to contribute to an improvement in construction ergonomics. Conclusions include: designers lack the requisite knowledge relative to the mass and density of materials; designers are thus precluded from conducting optimum design hazard identification and risk assessments, and tertiary built environment designer education does not enlighten designers relative to construction ergonomics. Recommendations include: tertiary built environment designer education should construction ergonomics; professional associations should raise the level of awareness relative to construction ergonomics, and design practices should include a category 'mass and density of materials' in their practice libraries.

  7. Compressive fatigue limit of four types of dental restorative materials.

    Science.gov (United States)

    Chen, Song; Öhman, Caroline; Jefferies, Steven R; Gray, Holly; Xia, Wei; Engqvist, Håkan

    2016-08-01

    The purpose of this study was to evaluate the quasi-static compressive strength and the compressive fatigue limit of four different dental restorative materials, before and after aging in distilled water for 30 days. A conventional glass ionomer cement (Fuji IX GP; IG), a zinc-reinforced glass ionomer cement (Chemfil rock; CF), a light curable resin-reinforced glass ionomer cement (Fuji II LC; LC) and a resin-based composite (Quixfil; QF) were investigated. Cylindrical specimens (4mm in diameter and 6mm in height) were prepared according to the manufacturer׳s instructions. The compressive fatigue limit was obtained using the staircase method. Samples were tested in distilled water at 37°C, at a frequency of 10Hz with 10(5) cycles set as run-out. 17 fatigue samples were tested for each group. Two-way ANOVA and one-way ANOVA followed by Tukey׳s post-hoc test were used to analyze the results. Among the four types of materials, the resin-based composite exhibited the highest compressive strength (244±13.0MPa) and compressive fatigue limit (134±7.8MPa), followed by the light-cured resin reinforced glass ionomer cement (168±8.5MPa and 92±6.6MPa, respectively) after one day of storage in distilled water. After being stored for 30 days, all specimens showed an increase in compressive strength. Aging showed no effect on the compressive fatigue limit of the resin-based composite and the light-cured resin reinforced glass ionomer cement, however, the conventional glass ionomer cements showed a drastic decrease (37% for IG, 31% for CF) in compressive fatigue limit. In conclusion, in the present study, resin modified GIC and resin-based composite were found to have superior mechanical properties to conventional GIC.

  8. Deflection of Resilient Materials for Reduction of Floor Impact Sound

    OpenAIRE

    Jung-Yoon Lee; Jong-Mun Kim

    2014-01-01

    Recently, many residents living in apartment buildings in Korea have been bothered by noise coming from the houses above. In order to reduce noise pollution, communities are increasingly imposing bylaws, including the limitation of floor impact sound, minimum thickness of floors, and floor soundproofing solutions. This research effort focused specifically on the deflection of resilient materials in the floor sound insulation systems of apartment houses. The experimental program involved condu...

  9. Limiter

    Science.gov (United States)

    Cohen, S.A.; Hosea, J.C.; Timberlake, J.R.

    1984-10-19

    A limiter with a specially contoured front face is provided. The front face of the limiter (the plasma-side face) is flat with a central indentation. In addition, the limiter shape is cylindrically symmetric so that the limiter can be rotated for greater heat distribution. This limiter shape accommodates the various power scrape-off distances lambda p, which depend on the parallel velocity, V/sub parallel/, of the impacting particles.

  10. Limitations and potentials of design materials within collaborative research practices

    DEFF Research Database (Denmark)

    Gunn, Wendy; Said Mosleh, Wafa

    The workshop explores the limitations and potentials of design materials to instigate cross-disciplinary research across a university’s technical, humanities and social science faculties. Our aim is to understand possibilities for wider participation within research processes and practices...... and to propose future directions for involving a broader grouping of peoples. During the workshop we will engage participants in the co-analysis of documentation generated through a series of open space research seminars, whereby design was the process of inquiry (2013 – ongoing at SDU Design Research). SDU...... Design Research, University of Southern Denmark attempts to provide a collaborative research environment, which embraces design from a set of complementary methods and methodologies. Findings from the workshop will contribute to a wider debate focusing on the affects of design materials in collaborations...

  11. A LOWER BOUND LIMIT ANALYSIS OF DUCTILE COMPOSITE MATERIALS

    Institute of Scientific and Technical Information of China (English)

    Zhang Hongtao; Liu Yinghua; Xu Bingye

    2005-01-01

    The plastic load-bearing capacity of ductile composites such as metal matrix composites is studied with an insight into the microstructures. The macroscopic strength of a composite is obtained by combining the homogenization theory with static limit analysis, where the temperature parameter method is used to construct the self-equilibrium stress field. An interface failure model is proposed to account for the effects of the interface on the failure of composites.The static limit analysis with the finite-element method is then formulated as a constrained nonlinear programming problem, which is solved by the Sequential Quadratic Programming (SQP)method. Finally, the macroscopic transverse strength of perforated materials, the macroscopic transverse and off-axis strength of fiber-reinforced composites are obtained through numerical calculation. The computational results are in good agreement with the experimental data.

  12. Modeling of space environment impact on nanostructured materials. General principles

    Science.gov (United States)

    Voronina, Ekaterina; Novikov, Lev

    2016-07-01

    In accordance with the resolution of ISO TC20/SC14 WG4/WG6 joint meeting, Technical Specification (TS) 'Modeling of space environment impact on nanostructured materials. General principles' which describes computer simulation methods of space environment impact on nanostructured materials is being prepared. Nanomaterials surpass traditional materials for space applications in many aspects due to their unique properties associated with nanoscale size of their constituents. This superiority in mechanical, thermal, electrical and optical properties will evidently inspire a wide range of applications in the next generation spacecraft intended for the long-term (~15-20 years) operation in near-Earth orbits and the automatic and manned interplanetary missions. Currently, ISO activity on developing standards concerning different issues of nanomaterials manufacturing and applications is high enough. Most such standards are related to production and characterization of nanostructures, however there is no ISO documents concerning nanomaterials behavior in different environmental conditions, including the space environment. The given TS deals with the peculiarities of the space environment impact on nanostructured materials (i.e. materials with structured objects which size in at least one dimension lies within 1-100 nm). The basic purpose of the document is the general description of the methodology of applying computer simulation methods which relate to different space and time scale to modeling processes occurring in nanostructured materials under the space environment impact. This document will emphasize the necessity of applying multiscale simulation approach and present the recommendations for the choice of the most appropriate methods (or a group of methods) for computer modeling of various processes that can occur in nanostructured materials under the influence of different space environment components. In addition, TS includes the description of possible

  13. Rumen Impaction with Foreign Indigestible Materials in Domestic ...

    African Journals Online (AJOL)

    Rumen Impaction with Foreign Indigestible Materials in Domestic Ruminants in Nigeria: A ... AFRICAN JOURNALS ONLINE (AJOL) · Journals · Advanced Search ... Rumen impaction due to foreign indigestible materials has become one of the ...

  14. Foreign Body Rumen Impaction with Indigestible Materials in ...

    African Journals Online (AJOL)

    Foreign Body Rumen Impaction with Indigestible Materials in Ruminants in Nigeria: A ... AFRICAN JOURNALS ONLINE (AJOL) · Journals · Advanced Search ... Rumen impaction due to foreign indigestible materials has become one of the ...

  15. Investigation of Microscopic Materials Limitations of Superconducting RF Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Anlage, Steven [Univ. of Maryland, College Park, MD (United States)

    2014-07-23

    The high-field performance of SRF cavities is often limited by breakdown events below the intrinsic limiting surface fields of Nb, and there is abundant evidence that these breakdown events are localized in space inside the cavity. Also, there is a lack of detailed understanding of the causal links between surface treatments and ultimate RF performance at low temperatures. An understanding of these links would provide a clear roadmap for improvement of SRF cavity performance, and establish a cause-and-effect ‘RF materials science’ of Nb. We propose two specific microscopic approaches to addressing these issues. First is a spatially-resolved local microwave-microscope probe that operates at SRF frequencies and temperatures to discover the microscopic origins of breakdown, and produce quantitative measurements of RF critical fields of coatings and films. Second, RF Laser Scanning Microscopy (LSM) has allowed visualization of RF current flow and sources of nonlinear RF response in superconducting devices with micro-meter spatial resolution. The LSM will be used in conjunction with surface preparation and characterization techniques to create definitive links between physical and chemical processing steps and ultimate cryogenic microwave performance. We propose to develop RF laser scanning microscopy of small-sample Nb pieces to establish surface-processing / RF performance relations through measurement of RF current distributions on micron-length scales and low temperatures.

  16. Habitability and Biosignature Preservation in Impact-Derived Materials

    Science.gov (United States)

    Sapers, H. M.; Pontefract, A.; Osinski, G. R.; Cannon, K. M.; Mustard, J. F.

    2016-05-01

    Meteorite impacts create environments conducive to microbial colonization. Biosignatures in impact-derived materials have been characterized on Earth. Impact environments comprise candidates for biosignature detection and preservation on Mars.

  17. Materials and society -- Impacts and responsibilities

    Energy Technology Data Exchange (ETDEWEB)

    Westwood, A.R.C.

    1995-11-01

    The needs of today`s advanced societies have moved well beyond the requirements for food and shelter, etc., and now are focused on such concerns as international peace and domestic security, affordable health care, the swift and secure transmission of information, the conservation of resources, and a clean environment. Progress in materials science and engineering is impacting each of these concerns. This paper will present some examples of how this is occurring, and then comment on ethical dilemmas that can arise as a consequence of technological advances. The need for engineers to participate more fully in the development of public policies that help resolve such dilemmas, and so promote the benefits of advancing technology to society, will be discussed.

  18. Materials and society — impacts and responsibilities

    Science.gov (United States)

    Westwood, A. R. C.

    1996-06-01

    The needs of today's advanced societies have moved well beyond the requirements for food and shelter, etc., and now are focused on such concerns as international peace and domestic security, affordable health care, the swift and secure transmission of information, the conservation of resources, and a clean environment. Progress in materials science and engineering is impacting each of these concerns. This article will present some examples of how this is occurring and then comment on ethical dilemmas that can arise as a consequence of technological advances. The need for engineers to participate more fully in the development of public policies that help resolve such dilemmas, and so promote the benefits of advancing technology to society, will be discussed.

  19. Tensile & impact behaviour of natural fibre-reinforced composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Tobias, B.C. [Victoria Univ. of Technology, Footscray (Australia). Dept. of Mechanical Engineering

    1993-12-31

    Short abaca fiber reinforced composite materials are fabricated and investigated for short term performance. Abaca plants which grow in abundance in Asia contain fibers that are inexpensive but underutilized. This study attempts to utilize the abaca fibers for composite material structure as a possible alternative to timber products in building applications. The composite material is fabricated using the hand lay-up method under varying fiber length and fiber volume fraction. The fibers are impregnated with a mixture of resins which cures at room temperature. A fabricating facility is designed to accommodate fabrication of lamina. Tensile and impact properties are determined in relation to the length and volume fraction of the fiber. For a given fiber length, the tensile and impact strength increase as the volume fraction increases up to a limiting value. And for a given fiber volume fraction, the tensile strength increases but the impact strength decreases as the fiber length increases. This behavior of abaca fiber-reinforced composite lamina will help in optimizing the design parameter in random composite panels.

  20. Impact of materials engineering on edge placement error (Conference Presentation)

    Science.gov (United States)

    Freed, Regina; Mitra, Uday; Zhang, Ying

    2017-04-01

    Transistor scaling has transitioned from wavelength scaling to multi-patterning techniques, due to the resolution limits of immersion of immersion lithography. Deposition and etch have enabled scaling in the by means of SADP and SAQP. Spacer based patterning enables extremely small linewidths, sufficient for several future generations of transistors. However, aligning layers in Z-direction, as well as aligning cut and via patterning layers, is becoming a road-block due to global and local feature variation and fidelity. This presentation will highlight the impact of deposition and etch on this feature alignment (EPE) and illustrate potential paths toward lowering EPE using material engineering.

  1. Advantages and limitations of exergy indicators to assess sustainability of bioenergy and biobased materials

    Energy Technology Data Exchange (ETDEWEB)

    Maes, Dries, E-mail: Dries.Maes@uhasselt.be; Van Passel, Steven, E-mail: Steven.Vanpassel@uhasselt.be

    2014-02-15

    Innovative bioenergy projects show a growing diversity in biomass pathways, transformation technologies and end-products, leading to complex new processes. Existing energy-based indicators are not designed to include multiple impacts and are too constrained to assess the sustainability of these processes. Alternatively, indicators based on exergy, a measure of “qualitative energy”, could allow a more holistic view. Exergy is increasingly applied in analyses of both technical and biological processes. But sustainability assessments including exergy calculations, are not very common and are not generally applicable to all types of impact. Hence it is important to frame the use of exergy for inclusion in a sustainability assessment. This paper reviews the potentials and the limitations of exergy calculations, and presents solutions for coherent aggregation with other metrics. The resulting approach is illustrated in a case study. Within the context of sustainability assessment of bioenergy, exergy is a suitable metric for the impacts that require an ecocentric interpretation, and it allows aggregation on a physical basis. The use of exergy is limited to a measurement of material and energy exchanges with the sun, biosphere and lithosphere. Exchanges involving services or human choices are to be measured in different metrics. This combination provides a more inclusive and objective sustainability assessment, especially compared to standard energy- or carbon-based indicators. Future applications of this approach in different situations are required to clarify the potential of exergy-based indicators in a sustainability context. -- Highlights: • Innovative bioenergy projects require more advanced sustainability assessments to incorporate all environmental impacts. • Exergy-based indicators provide solutions for objective and robust measurements. • The use of exergy in a sustainability assessment is limited to material exchanges, excluding exchanges with society

  2. Impact of diffusion limited aggregates of impurities on nematic ordering

    Science.gov (United States)

    Harkai, S.; Ambrožič, M.; Kralj, S.

    2017-02-01

    We study the impact of random bond-type disorder on two-dimensional (2D) orientational ordering of nematic liquid crystal (LC) configurations. The lattice Lebwohl-Lasher pseudospin model is used to model orientational ordering perturbed by frozen-in rod-like impurities of concentration p exhibiting the isotropic orientational probability distribution. The impurities are either (i) randomly spatially distributed or (ii) form diffusion limited aggregation (DLA)-type patterns characterized by the fractal dimensions df, where we consider cases df ∼ 1.7 and df ∼ 1.9. The degree of orientational ordering is quantified in terms of the orientational pair correlation function G(r) . Simulations reveal that the DLA pattern imposed disorder has a significantly weaker impact for a given concentration of impurities. Furthermore, if samples are quenched from the isotropic LC phase, then the fractal dimension is relatively strongly imprinted on quantitative characteristics of G(r) .

  3. Standard test method for instrumented impact testing of metallic materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This standard establishes the requirements for performing instrumented Charpy V-Notch (CVN) and instrumented Miniaturized Charpy V-Notch (MCVN) impact tests on metallic materials. This method, which is based on experience developed testing steels, provides further information (in addition to the total absorbed energy) on the fracture behavior of the tested materials. Minimum requirements are given for measurement and recording equipment such that similar sensitivity and comparable total absorbed energy measurements to those obtained in Test Methods E 23 and E 2248 are achieved. 1.2 The values stated in SI units are to be regarded as the standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  4. Deflection of resilient materials for reduction of floor impact sound.

    Science.gov (United States)

    Lee, Jung-Yoon; Kim, Jong-Mun

    2014-01-01

    Recently, many residents living in apartment buildings in Korea have been bothered by noise coming from the houses above. In order to reduce noise pollution, communities are increasingly imposing bylaws, including the limitation of floor impact sound, minimum thickness of floors, and floor soundproofing solutions. This research effort focused specifically on the deflection of resilient materials in the floor sound insulation systems of apartment houses. The experimental program involved conducting twenty-seven material tests and ten sound insulation floating concrete floor specimens. Two main parameters were considered in the experimental investigation: the seven types of resilient materials and the location of the loading point. The structural behavior of sound insulation floor floating was predicted using the Winkler method. The experimental and analytical results indicated that the cracking strength of the floating concrete floor significantly increased with increasing the tangent modulus of resilient material. The deflection of the floating concrete floor loaded at the side of the specimen was much greater than that of the floating concrete floor loaded at the center of the specimen. The Winkler model considering the effect of modulus of resilient materials was able to accurately predict the cracking strength of the floating concrete floor.

  5. Deflection of Resilient Materials for Reduction of Floor Impact Sound

    Directory of Open Access Journals (Sweden)

    Jung-Yoon Lee

    2014-01-01

    Full Text Available Recently, many residents living in apartment buildings in Korea have been bothered by noise coming from the houses above. In order to reduce noise pollution, communities are increasingly imposing bylaws, including the limitation of floor impact sound, minimum thickness of floors, and floor soundproofing solutions. This research effort focused specifically on the deflection of resilient materials in the floor sound insulation systems of apartment houses. The experimental program involved conducting twenty-seven material tests and ten sound insulation floating concrete floor specimens. Two main parameters were considered in the experimental investigation: the seven types of resilient materials and the location of the loading point. The structural behavior of sound insulation floor floating was predicted using the Winkler method. The experimental and analytical results indicated that the cracking strength of the floating concrete floor significantly increased with increasing the tangent modulus of resilient material. The deflection of the floating concrete floor loaded at the side of the specimen was much greater than that of the floating concrete floor loaded at the center of the specimen. The Winkler model considering the effect of modulus of resilient materials was able to accurately predict the cracking strength of the floating concrete floor.

  6. IMPACTS OF LOWER SPEED LIMITS IN SOUTH AUSTRALIA

    Directory of Open Access Journals (Sweden)

    J.E. WOOLLEY

    2002-01-01

    This paper reports on a more holistic assessment of such schemes taking into account factors in addition to speed and crashes including: traffic volume displacement, physical road network characteristics, environmental factors, community ownership and acceptance, enforcement effort and impact on travel times. The research work has included the analysis of extensive traffic data, community surveys and focus groups, the collection of environmental and travel time data from an instrumented probe vehicle and the computer modelling of road networks. The work reported is based on over 10 years of working with a 40km/h lower urban speed limit area in South Australia. The paper expands the notion of using speed and crash outcomes as the only criteria for measuring the success of lower speed limit schemes.

  7. 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

  8. Impact of erosive conditions on tooth-colored restorative materials.

    Science.gov (United States)

    Attin, Thomas; Wegehaupt, Florian J

    2014-01-01

    To give an overview of the impact of erosive conditions on the behavior of tooth-colored restoratives and performance of dental adhesives. Acid-induced erosive lesions of enamel and dentin often need restorative procedures for rehabilitation. Nowadays, mostly tooth-colored restoratives (ceramics or resin composites), which are adhesively fixed to the dental substrate are used for this purpose. In some cases it might be necessary to seal the exposed dentin before achieving this goal in order to combat hypersensitivities and to protect those teeth from further erosive and abrasive loss. Moreover, it is conceivable that patients will fall back into their old "erosive behavior" after the application of restoratives. The following overview describes in how far intra-oral erosive conditions might affect the integrity of restorative materials, such as composite resins and ceramics, or of dentin sealants. Additionally, the use of erosively altered enamel and dentin as substrate for adhesive technologies is elucidated. In the literature, information of the behavior of tooth-colored restoratives under still persisting erosive conditions are limited and mostly based on in vitro-studies. There is information that the adhesion of dental adhesives to eroded dentin is compromised as compared to regular dentin. The impact of erosive conditions relevant for the oral cavity on ceramics and resin composites seems to be rather low, although only few clinical studies are available. The review showed that erosive conditions might have only little impact on behavior of tooth-colored restorative materials, such as composites and ceramics. Dentin sealants also seem to be rather resistant against erosive conditions and might therefore serve as an intermediary treatment option for exposed dentin surfaces. The adhesion of dentin adhesives to eroded dentin might be increased by mechanical pre-treatment of the substrate, but needs further investigation. Copyright © 2013 Academy of Dental

  9. Transition Metal Complex/Polymer Systems as Optical Limiting Materials

    Science.gov (United States)

    2013-05-01

    material has a relatively low viscosity and allows the possibility of exploration of bimolecular reactions of encapsulated chromophores with added...dynamics in the host-guest complex of azidopermethylated cyclodextrin (host) and ademantylamide (guest). A clear induction period indicates that the IR

  10. 46 CFR 56.60-2 - Limitations on materials.

    Science.gov (United States)

    2010-10-01

    ... Boiler and Pressure Vessel Code * ASTM specifications Source of allowable stress Notes Ferrous Materials... 16 (soft and half hard tempers) See footnote 5 (5,7). B 21 (alloys A, B, and C) See footnote 8 (8). B 124: Alloy 377 See footnotes 5 and 9 (5,9). Alloy 464 See footnote 8 (8,10). Alloy 655 See footnote 11...

  11. Tree Diversity Limits the Impact of an Invasive Forest Pest.

    Science.gov (United States)

    Guyot, Virginie; Castagneyrol, Bastien; Vialatte, Aude; Deconchat, Marc; Selvi, Federico; Bussotti, Filippo; Jactel, Hervé

    2015-01-01

    The impact of invasive herbivore species may be lower in more diverse plant communities due to mechanisms of associational resistance. According to the "resource concentration hypothesis" the amount and accessibility of host plants is reduced in diverse plant communities, thus limiting the exploitation of resources by consumers. In addition, the "natural enemy hypothesis" suggests that richer plant assemblages provide natural enemies with more complementary resources and habitats, thus promoting top down regulation of herbivores. We tested these two hypotheses by comparing crown damage by the invasive Asian chestnut gall wasp (Dryocosmus kuriphilus) on chestnut trees (Castanea sativa) in pure and mixed stands in Italy. We estimated the defoliation on 70 chestnut trees in 15 mature stands sampled in the same region along a gradient of tree species richness ranging from one species (chestnut monocultures) to four species (mixtures of chestnut and three broadleaved species). Chestnut defoliation was significantly lower in stands with higher tree diversity. Damage on individual chestnut trees decreased with increasing height of neighboring, heterospecific trees. These results suggest that conservation biological control method based on tree species mixtures might help to reduce the impact of the Asian chestnut gall.

  12. Tree Diversity Limits the Impact of an Invasive Forest Pest.

    Directory of Open Access Journals (Sweden)

    Virginie Guyot

    Full Text Available The impact of invasive herbivore species may be lower in more diverse plant communities due to mechanisms of associational resistance. According to the "resource concentration hypothesis" the amount and accessibility of host plants is reduced in diverse plant communities, thus limiting the exploitation of resources by consumers. In addition, the "natural enemy hypothesis" suggests that richer plant assemblages provide natural enemies with more complementary resources and habitats, thus promoting top down regulation of herbivores. We tested these two hypotheses by comparing crown damage by the invasive Asian chestnut gall wasp (Dryocosmus kuriphilus on chestnut trees (Castanea sativa in pure and mixed stands in Italy. We estimated the defoliation on 70 chestnut trees in 15 mature stands sampled in the same region along a gradient of tree species richness ranging from one species (chestnut monocultures to four species (mixtures of chestnut and three broadleaved species. Chestnut defoliation was significantly lower in stands with higher tree diversity. Damage on individual chestnut trees decreased with increasing height of neighboring, heterospecific trees. These results suggest that conservation biological control method based on tree species mixtures might help to reduce the impact of the Asian chestnut gall.

  13. Superconducting Materials and Conductors : Fabrication and Limiting Parameters

    CERN Document Server

    Bottura, Luca

    2012-01-01

    Superconductivity is the technology that enabled the construction of the most recent generation of high-energy particle accelerators, the largest scientific instruments ever built. In this review we trace the evolution of superconducting materials for particle accelerator magnets, from the first steps in the late 1960s, through the rise and glory of Nb–Ti in the 1970s, till the 2010s, and the promises of Nb3Sn for the 2020s. We conclude with a perspective on the opportunities for high-temperature superconductors (HTSs). Many such reviews have been written in the past, as witnessed by the long list of references provided. In this review we put particular emphasis on the practical aspects of wire and tape manufacturing, cabling, engineering performance, and potential for use in accelerator magnets, while leaving in the background matters such as the physics of superconductivity and fundamental material issues.

  14. Plasma processing of fibre materials for enhanced impact protection

    NARCIS (Netherlands)

    Creyghton, Y.L.M.; Simor, M.

    2009-01-01

    The performance of lightweight impact protective clothing depends on the constituting materials, their assembly in a system and interaction under various dynamic impact conditions. In this paper an overview of options for improved impact protective clothing systems based on a new plasma technology i

  15. Plasma processing of fibre materials for enhanced impact protection

    NARCIS (Netherlands)

    Creyghton, Y.L.M.; Simor, M.

    2009-01-01

    The performance of lightweight impact protective clothing depends on the constituting materials, their assembly in a system and interaction under various dynamic impact conditions. In this paper an overview of options for improved impact protective clothing systems based on a new plasma technology i

  16. Plasma processing of fibre materials for enhanced impact protection

    NARCIS (Netherlands)

    Creyghton, Y.L.M.; Simor, M.

    2009-01-01

    The performance of lightweight impact protective clothing depends on the constituting materials, their assembly in a system and interaction under various dynamic impact conditions. In this paper an overview of options for improved impact protective clothing systems based on a new plasma technology

  17. Limit State of Materials and Structures Direct Methods 2

    CERN Document Server

    Oueslati, Abdelbacet; Charkaluk, Eric; Tritsch, Jean-Bernard

    2013-01-01

    To determine the carrying capacity of a structure or a structural element susceptible to operate beyond the elastic limit is an important task in many situations of both mechanical and civil engineering. The so-called “direct methods” play an increasing role due to the fact that they allow rapid access to the request information in mathematically constructive manners. They embrace Limit Analysis, the most developed approach now widely used, and Shakedown Analysis, a powerful extension to the variable repeated loads potentially more economical than step-by-step inelastic analysis. This book is the outcome of a workshop held at the University of Sciences and Technology of Lille. The individual contributions stem from the areas of new numerical developments rendering these methods more attractive for industrial design, extension of the general methodology to new horizons, probabilistic approaches and concrete technological applications.

  18. Investigating the Materials Limits on Coherence in Superconducting Charge Qubits

    Science.gov (United States)

    2014-12-04

    mesoscopic effects in superconductors on the coherence of qubits and on losses in superconducting films , and comparing these to experiment. This...on the superconducting films themselves, or at the metal-substrate interfaces) was the main limitation on qubit lifetimes, which were then in the...quality. We also developed and tested the “vertical transmon” design, where the transmon capacitors are formed through the bulk thickness of the

  19. Modeling of Impact Properties of Auxetic Materials: Phase 1

    Science.gov (United States)

    2013-08-01

    underlying metal substrate from impact damage will be determined, and compared to the effect of solid polymer coatings (containing no honeycomb shaped air...higher indentation resistance, higher fracture toughness and greater resistance to impact damage . These unique features of the auxetic materials make... Elastoplasticity of auxetic materials, Computational Material Science, in press. [24] Horrigan, E.J., Smith, C.W., Scarpa, F.L., Gaspar, N., Javadi, A.A

  20. Evaluation of Barrier Cable Impact Pad Materials

    Science.gov (United States)

    1988-03-01

    ACTUAL BATCH DATA CU MATERIAL SOLID VOLUME SAT. SURF DRY SAT. . O,- DRY WATER ACT’.AL CU FT/BATCH BATCH WT. LB FACTOR EATCl ,9 CORRECTION. LB 1ATC. -T...POZZDOTHER CEMENT PROPORTIONS CALCULATED BATCH DATA (I CU YO) ACTUAL BATCH CATA CU =T SOLID VOLUME SAT. SURF DRY SAT. 3, DRY WATER MATERIAL CU FT

  1. Impact of Individualized Instructional Materials on Technology Education Programs.

    Science.gov (United States)

    Welty, Kenneth; Tsai, Wei-Kun

    1995-01-01

    A survey of technology instructors in junior and senior high schools determined the impact of adopting modular programs using individualized instructional materials (IIMs) on their teaching styles: teacher-directed methods decreased; use of student-oriented materials increased, while use of teacher-oriented materials decreased; frequency of…

  2. Impact of Individualized Instructional Materials on Technology Education Programs.

    Science.gov (United States)

    Welty, Kenneth; Tsai, Wei-Kun

    1995-01-01

    A survey of technology instructors in junior and senior high schools determined the impact of adopting modular programs using individualized instructional materials (IIMs) on their teaching styles: teacher-directed methods decreased; use of student-oriented materials increased, while use of teacher-oriented materials decreased; frequency of…

  3. Work criteria for stress conditions using heat-resistant materials having limited endurance

    Energy Technology Data Exchange (ETDEWEB)

    Kheyn, Ye.A.

    1980-01-01

    The effect of stress concentrations and material properties on endurance limits. The parameter properties are theoretically founded and define the comparative sensitivity of materials to stress concentration over prolonged statistical breakdowns.

  4. 49 CFR 173.423 - Requirements for multiple hazard limited quantity Class 7 (radioactive) materials.

    Science.gov (United States)

    2010-10-01

    ... Class 7 (radioactive) materials. 173.423 Section 173.423 Transportation Other Regulations Relating to... MATERIALS REGULATIONS SHIPPERS-GENERAL REQUIREMENTS FOR SHIPMENTS AND PACKAGINGS Class 7 (Radioactive) Materials § 173.423 Requirements for multiple hazard limited quantity Class 7 (radioactive) materials....

  5. Gelatin as a new humidity sensing material: Characterization and limitations

    Energy Technology Data Exchange (ETDEWEB)

    Shapardanis, Steven [School of Engineering and Technology, Central Michigan University, Mt. Pleasant, Michigan, 48859 (United States); Hudpeth, Mathew [Department of Physics, Central Michigan University, Mt. Pleasant, Michigan, 48859 (United States); Kaya, Tolga, E-mail: kaya2t@cmich.edu [School of Engineering and Technology, Central Michigan University, Mt. Pleasant, Michigan, 48859 (United States); Science of Advanced Materials Program, Central Michigan University, Mt. Pleasant, Michigan, 48859 (United States)

    2014-12-15

    The goal of this work is to assert the utility of collagen and its denatured counterpart gelatin as cost-effective alternatives to existing sensing layers comprised of polymers. Rather than producing a material that will need to be discarded or recycled, collagen, as a by-product of the meat and leather industry, could be repurposed. This work examines the feasibility of using collagen as a sensing layer. Planar electrodes were patterned with lift-off process to work with the natural characteristics of gelatin by utilizing metal vapor deposition, spin coating, and photolithography. Characterization methods have also been optimized through the creation of specialized humidity chambers that isolate specific characteristics such as response time, accuracy, and hysteresis. Collagen-based sensors are found to have a sensitivity to moisture in the range of 0.065 pF/%RH. Diffusion characteristics were also analyzed with the diffusion coefficient found to be 2.5 × 10{sup −5} cm{sup 2}/s. Absorption and desorption times were found to be 20 seconds and 8 seconds, respectively. Hysteresis present in the data is attributed to temperature cross-sensitivity. Ultimately, the utility of collagen as a dielectric sensing material is, in part, due to its fibrous macrostructures as well its hydrophilic sites along the peptide chains. Gelatin was patterned between and below interdigitated copper electrodes and tested as a relative humidity sensor. This work shows that gelatin, which is inexpensive, widely available, and easy to process, can be an effective dielectric sensing polymer for capacitive-type relative humidity sensors.

  6. Gelatin as a new humidity sensing material: Characterization and limitations

    Directory of Open Access Journals (Sweden)

    Steven Shapardanis

    2014-12-01

    Full Text Available The goal of this work is to assert the utility of collagen and its denatured counterpart gelatin as cost-effective alternatives to existing sensing layers comprised of polymers. Rather than producing a material that will need to be discarded or recycled, collagen, as a by-product of the meat and leather industry, could be repurposed. This work examines the feasibility of using collagen as a sensing layer. Planar electrodes were patterned with lift-off process to work with the natural characteristics of gelatin by utilizing metal vapor deposition, spin coating, and photolithography. Characterization methods have also been optimized through the creation of specialized humidity chambers that isolate specific characteristics such as response time, accuracy, and hysteresis. Collagen-based sensors are found to have a sensitivity to moisture in the range of 0.065 pF/%RH. Diffusion characteristics were also analyzed with the diffusion coefficient found to be 2.5 × 10−5 cm2/s. Absorption and desorption times were found to be 20 seconds and 8 seconds, respectively. Hysteresis present in the data is attributed to temperature cross-sensitivity. Ultimately, the utility of collagen as a dielectric sensing material is, in part, due to its fibrous macrostructures as well its hydrophilic sites along the peptide chains. Gelatin was patterned between and below interdigitated copper electrodes and tested as a relative humidity sensor. This work shows that gelatin, which is inexpensive, widely available, and easy to process, can be an effective dielectric sensing polymer for capacitive-type relative humidity sensors.

  7. Gelatin as a new humidity sensing material: Characterization and limitations

    Science.gov (United States)

    Shapardanis, Steven; Hudpeth, Mathew; Kaya, Tolga

    2014-12-01

    The goal of this work is to assert the utility of collagen and its denatured counterpart gelatin as cost-effective alternatives to existing sensing layers comprised of polymers. Rather than producing a material that will need to be discarded or recycled, collagen, as a by-product of the meat and leather industry, could be repurposed. This work examines the feasibility of using collagen as a sensing layer. Planar electrodes were patterned with lift-off process to work with the natural characteristics of gelatin by utilizing metal vapor deposition, spin coating, and photolithography. Characterization methods have also been optimized through the creation of specialized humidity chambers that isolate specific characteristics such as response time, accuracy, and hysteresis. Collagen-based sensors are found to have a sensitivity to moisture in the range of 0.065 pF/%RH. Diffusion characteristics were also analyzed with the diffusion coefficient found to be 2.5 × 10-5 cm2/s. Absorption and desorption times were found to be 20 seconds and 8 seconds, respectively. Hysteresis present in the data is attributed to temperature cross-sensitivity. Ultimately, the utility of collagen as a dielectric sensing material is, in part, due to its fibrous macrostructures as well its hydrophilic sites along the peptide chains. Gelatin was patterned between and below interdigitated copper electrodes and tested as a relative humidity sensor. This work shows that gelatin, which is inexpensive, widely available, and easy to process, can be an effective dielectric sensing polymer for capacitive-type relative humidity sensors.

  8. Ingestion of microplastic has limited impact on a marine larva.

    Science.gov (United States)

    Kaposi, Katrina L; Mos, Benjamin; Kelaher, Brendan P; Dworjanyn, Symon A

    2014-01-01

    There is increasing concern about the impacts of microplastics (marine biota. Microplastics may be mistaken for food items and ingested by a wide variety of organisms. While the effects of ingesting microplastic have been explored for some adult organisms, there is poor understanding of the effects of microplastic ingestion on marine larvae. Here, we investigated the ingestion of polyethylene microspheres by larvae of the sea urchin, Tripneustes gratilla. Ingestion rates scaled with the concentration of microspheres. Ingestion rates were, however, reduced by biological fouling of microplastic and in the presence of phytoplankton food. T. gratilla larvae were able to egest microspheres from their stomach within hours of ingestion. A microsphere concentration far exceeding those recorded in the marine environment had a small nondose dependent effect on larval growth, but there was no significant effect on survival. In contrast, environmentally realistic concentrations appeared to have little effect. Overall, these results suggest that current levels of microplastic pollution in the oceans only pose a limited threat to T. gratilla and other marine invertebrate larvae, but further research is required on a broad range of species, trophic levels, and polymer types.

  9. Ultrafast impact dynamics of reactive materials (Dlott)

    Science.gov (United States)

    2013-04-16

    Submitted Patents Awarded Awards Jupiter Laser Facility Program Advisory Committee, Lawrence Livermore National Laboratory, 2008, 2011 Executive...related materials such as B/Teflon) to ultrafast laser flash heating. 36-39 In fact during the project period we wrapped up the flash-heating

  10. Experimental techniques for design of impact-resistant material (poster)

    NARCIS (Netherlands)

    Fan, J.; Weerheijm, J.; Sluys, L.J.

    2013-01-01

    Some polymers are not only transparent and lightweight, but also impact and ballistic resistant. Designing and preparing such polymeric materials with a high impact‐resistant performance is of importance to e.g. aviation, military and windscreen applications.

  11. Experimental techniques for design of impact-resistant material (poster)

    NARCIS (Netherlands)

    Fan, J.; Weerheijm, J.; Sluys, L.J.

    2013-01-01

    Some polymers are not only transparent and lightweight, but also impact and ballistic resistant. Designing and preparing such polymeric materials with a high impact‐resistant performance is of importance to e.g. aviation, military and windscreen applications.

  12. Experimental hypervelocity impact effects on simulated planetesimal materials.

    Science.gov (United States)

    Tedeschi, W. J.; Remo, J. L.; Schulze, J. F.; Young, R. P.

    Experimental results are presented from a series of hypervelocity impact tests on simulated comet and asteroid materials for the purpose of characterizing their response to hypervelocity kinetic energy impacts. The test objectives were to collect target response phenomenology data on cratering, momentum deposition and enhancement, target fragmentation, and material response under hypervelocity impact loading conditions. A carefully designed ballistic pendulum was used to measure momentum deposition into the targets. Observations and measurements of the impacted samples provide important insights into the response of these materials to kinetic energy impacts, especially in regards to unexpectedly large measured values of momentum enhancement to some of the targets. Such information is required to allow one to successfully deflect or fragment comets or asteroids which might someday be detected on collision trajectories with Earth.

  13. Influence of Material Distribution on Impact Resistance of Hybrid Composites

    Science.gov (United States)

    Abatan, Ayu; Hu, Hurang

    1998-01-01

    Impact events occur in a wide variety of circumstances. A typical example is a bullet impacting a target made of composite material. These impact events produce time-varying loads on a structure that can result in damage. As a first step to understanding the damage resistance issue in composite laminates, an accurate prediction of the transient response during an impact event is necessary. The analysis of dynamic loadings on laminated composite plates has undergone considerable development recently. Rayleigh-Ritz energy method was used to determine the impact response of laminated plates. The impact response of composite plates using shear deformation plate theory was analyzed. In recent work a closed-form solution was obtained for a rectangular plate with four edges simply supported subjected to a center impact load using classical plate theory. The problem was further investigated and the analysis results compared of both classical plate theory and shear deformation theory, and found that classical plate theory predicts very accurate results for the range of small deformations considered. In this study, the influence of cross sectional material distribution on the comparative impact responses of hybrid metal laminates subjected to low and medium velocity impacts is investigated. A simple linear model to evaluate the magnitude of the impact load is proposed first, and it establishes a relation between the impact velocity and the impact force. Then a closed-form solution for impact problem is presented. The results were compared with the finite element analysis results. For an 11 layer-hybrid laminate, the impact response as a function of material distribution in cross-section is presented. With equal areal weight, the effect of the number of laminate layers on the impact resistance is also investigated. Finally, the significance of the presented results is discussed.

  14. Infrared thermography to impact damaging of composite materials

    Science.gov (United States)

    Boccardi, Simone; Boffa, Natalino D.; Carlomagno, Giovanni M.; Meola, Carosena; Ricci, Fabrizio; Russo, Pietro; Simeoli, Giorgio

    2017-04-01

    Composite materials are becoming ever more popular and being used in an increasing number of applications. This because, to meet the users' demand, it is possible to create a new material of given characteristics in a quite simple way by changing either the type of matrix, or reinforcement. Of course, any new material requires characterization for its appropriate exploitation. In this context, infrared thermography (IRT) represents a viable means since it is non-contact, non-intrusive and can be used either for non-destructive evaluation to detect manufacturing defects, or fatigue induced degradation, or else for monitoring online the response to applied loads. In this work, IRT is used to investigate different types of composite materials which are based on either a thermoset, or a thermoplastic matrix, which may be neat, or modified by addition of a percentage of a specific compatibilizing agent, and reinforced with carbon, glass, or jute fibers. IRT is used with a twofold function. First, to non-destructively evaluate, with the lock-in technique, materials before and after impact to either assure absence of manufacturing defects, or discover the damage caused by the impact. Second, IRT is used to visualize thermal effects, which develop when the material is subjected to impact. The obtained results show that it is possible to follow the material bending, delamination and eventual failure under impact and get information, which may be valuable to deepen the complex impact damaging mechanisms of composites

  15. Impact of Universities' Promotional Materials on College Choice.

    Science.gov (United States)

    Armstrong, Jami J.; Lumsden, D. Barry

    1999-01-01

    Evaluated the impact of printed promotional materials on the recruitment of college freshmen using focus groups of students attending a large, southern metropolitan university. Students provided detailed suggestions on ways to improve the method of distribution, graphic design, and content of the materials. (Author/DB)

  16. Material transfer agreements : A review of modes and impacts

    NARCIS (Netherlands)

    Rodriguez, V.

    2009-01-01

    Sharing or exchanging research material is typically formalised through material transfer agreements. The aim of this article is to put into critical perspective the empirical findings on modes and impacts of these agreements vis-a-vis commonly accepted concerns formulated in a Mertonian fashion for

  17. Material Transfer Agreements: A Review of Modes and Impacts

    NARCIS (Netherlands)

    Rodriguez, Victor

    2009-01-01

    Sharing or exchanging research material is typically formalised through material transfer agreements. The aim of this article is to put into critical perspective the empirical findings on modes and impacts of these agreements vis--vis commonly accepted concerns formulated in a Mertonian fashion for

  18. Propagation law of impact elastic wave based on specific materials

    Directory of Open Access Journals (Sweden)

    Chunmin CHEN

    2017-02-01

    Full Text Available In order to explore the propagation law of the impact elastic wave on the platform, the experimental platform is built by using the specific isotropic materials and anisotropic materials. The glass cloth epoxy laminated plate is used for anisotropic material, and an organic glass plate is used for isotropic material. The PVDF sensors adhered on the specific materials are utilized to collect data, and the elastic wave propagation law of different thick plates and laminated plates under impact conditions is analyzed. The Experimental results show that in anisotropic material, transverse wave propagation speed along the fiber arrangement direction is the fastest, while longitudinal wave propagation speed is the slowest. The longitudinal wave propagation speed in anisotropic laminates is much slower than that in the laminated thick plates. In the test channel arranged along a particular angle away from the central region of the material, transverse wave propagation speed is larger. Based on the experimental results, this paper proposes a material combination mode which is advantageous to elastic wave propagation and diffusion in shock-isolating materials. It is proposed to design a composite material with high acoustic velocity by adding regularly arranged fibrous materials. The overall design of the barrier material is a layered structure and a certain number of 90°zigzag structure.

  19. Nanoscaled In$_2$O$_3$:Sn films as material for thermoelectric conversion: achievements and limitations

    Indian Academy of Sciences (India)

    G KOROTCENKOV; V BRINZARI; B K CHO

    2016-09-01

    In this paper, thermoelectric properties of nanoscaled In$_2$O$_3$:Sn films are considered. The limitations that may appear during the usage of such materials in devices developed for the market of thermoelectric generatorsand refrigerators are also analysed. It is shown that nanoscaled In$_2$O$_3$:Sn is a promising material for thermoelectric applications. It is also established that insufficient thermal stability of nanostructured materials is themain limitation of these materials application in high-temperature thermoelectric converters. Optimization of grain boundary parameters and the usage of specific surrounding atmosphere can significantly improve the efficiency of thermoelectric conversion of nanostructured materials in the region of intermediate temperatures.

  20. 75 FR 59197 - Hazardous Materials: Limiting the Use of Electronic Devices by Highway

    Science.gov (United States)

    2010-09-27

    ...: Limiting the Use of Electronic Devices by Highway AGENCY: Pipeline and Hazardous Materials Safety... Materials Safety Administration (PHMSA) proposes to prohibit texting on electronic devices by drivers during... materials community to the dangers associated with the use of mobile phones and electronic devices...

  1. 76 FR 10771 - Hazardous Materials: Limiting the Use of Electronic Devices by Highway

    Science.gov (United States)

    2011-02-28

    ...: Limiting the Use of Electronic Devices by Highway AGENCY: Pipeline and Hazardous Materials Safety... materials as defined in this section. b. Section 383.5 indicates that an electronic device includes, but is... involving hazardous materials when CMV drivers are distracted by electronic devices. Accordingly, the...

  2. 78 FR 76888 - MAP-21 Comprehensive Truck Size and Weight Limits Study Materials

    Science.gov (United States)

    2013-12-19

    ... Federal Highway Administration MAP-21 Comprehensive Truck Size and Weight Limits Study Materials AGENCY... for Progress in the 21st Century Act (MAP-21) Comprehensive Truck Size and Weight Limits Study, which... public meetings on the MAP-21 Comprehensive Truck Size and Weight Limits Study and to announce...

  3. 10 CFR 51.76 - Draft environmental impact statement-limited work authorization.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Draft environmental impact statement-limited work...-Regulations Implementing Section 102(2) Draft Environmental Impact Statements-Production and Utilization Facilities § 51.76 Draft environmental impact statement—limited work authorization. The NRC will prepare a...

  4. The impact crater as a habitat: effects of impact processing of target materials.

    Science.gov (United States)

    Cockell, Charles S; Osinski, Gordon R; Lee, Pascal

    2003-01-01

    Impact structures are a rare habitat on Earth. However, where they do occur they can potentially have an important influence on the local ecology. Some of the types of habitat created in the immediate post-impact environment are not specific to the impact phenomenon, such as hydrothermal systems and crater lakes that can be found, for instance, in post-volcanic environments, albeit with different thermal characteristics than those associated with impact. However, some of the habitats created are specifically linked to processes of impact processing. Two examples of how impact processing of target materials has created novel habitats that improve the opportunities for colonization are found in the Haughton impact structure in the Canadian High Arctic. Impact-shocked rocks have become a habitat for endolithic microorganisms, and large, impact-shattered blocks of rock are used as resting sites by avifauna. However, some materials produced by an impact, such as melt sheet rocks, can make craters more biologically depauperate than the area surrounding them. Although there are no recent craters with which to study immediate post-impact colonization, these data yield insights into generalized mechanisms of how impact processing can influence post-impact succession. Because impact events are one of a number of processes that can bring localized destruction to ecosystems, understanding the manner in which impact structures are recolonized is of ecological interest. Impact craters are a universal phenomenon on solid planetary surfaces, and so they are of potential biological relevance on other planetary surfaces, particularly Mars.

  5. The impact of teachers' limited English proficiency on English ...

    African Journals Online (AJOL)

    ... role of language in teacher education programmes and in children's learning is crucial. This study focuses on the use of English as the language of learning and ... its impact on the language development of English second language (ESL) ...

  6. A Market Model for Evaluating Technologies That Impact Critical-Material Intensity

    Science.gov (United States)

    Iyer, Ananth V.; Vedantam, Aditya

    2016-07-01

    A recent Critical Materials Strategy report highlighted the supply chain risk associated with neodymium and dysprosium, which are used in the manufacturing of neodymium-iron-boron permanent magnets (PM). In response, the Critical Materials Institute is developing innovative strategies to increase and diversify primary production, develop substitutes, reduce material intensity and recycle critical materials. Our goal in this paper is to propose an economic model to quantify the impact of one of these strategies, material intensity reduction. Technologies that reduce material intensity impact the economics of magnet manufacturing in multiple ways because of: (1) the lower quantity of critical material required per unit PM, (2) more efficient use of limited supply, and (3) the potential impact on manufacturing cost. However, the net benefit of these technologies to a magnet manufacturer is an outcome of an internal production decision subject to market demand characteristics, availability and resource constraints. Our contribution in this paper shows how a manufacturer's production economics moves from a region of being supply-constrained, to a region enabling the market optimal production quantity, to a region being constrained by resources other than critical materials, as the critical material intensity changes. Key insights for engineers and material scientists are: (1) material intensity reduction can have a significant market impact, (2) benefits to manufacturers are non-linear in the material intensity reduction, (3) there exists a threshold value for material intensity reduction that can be calculated for any target PM application, and (4) there is value for new intellectual property (IP) when existing manufacturing technology is IP-protected.

  7. Direct methods for limit and shakedown analysis of structures advanced computational algorithms and material modelling

    CERN Document Server

    Pisano, Aurora; Weichert, Dieter

    2015-01-01

    Articles in this book examine various materials and how to determine directly the limit state of a structure, in the sense of limit analysis and shakedown analysis. Apart from classical applications in mechanical and civil engineering contexts, the book reports on the emerging field of material design beyond the elastic limit, which has further industrial design and technological applications. Readers will discover that “Direct Methods” and the techniques presented here can in fact be used to numerically estimate the strength of structured materials such as composites or nano-materials, which represent fruitful fields of future applications.   Leading researchers outline the latest computational tools and optimization techniques and explore the possibility of obtaining information on the limit state of a structure whose post-elastic loading path and constitutive behavior are not well defined or well known. Readers will discover how Direct Methods allow rapid and direct access to requested information in...

  8. Impact of SARS on China's economy limited

    Institute of Scientific and Technical Information of China (English)

    TaoRunyuan

    2003-01-01

    China's economic upsurge cannot be reversed by the severe acute respiratory syndrome (SARS) now ravaging some parts of the country. China's economy will maintain its steady growth momentum despite the SARS' impact to some extent on investment, consumption andexport, according to a number of noted Chinese experts.

  9. Instrumentation for Spectroscopy of Impact Initiation of Reactive Materials

    Science.gov (United States)

    2015-04-14

    5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 5c. PROGRAM ELEMENT NUMBER 5b. GRANT NUMBER 5a. CONTRACT NUMBER Form Approved OMB NO...Instrumentation for spectroscopy of impact initiation of reactive materials Instrumentation was acquired that allowed for acquisition of emission...will be used to study the emission from small particles of reactive nanomaterials that are initiated by impact with a flyer plate. The emission

  10. Impact of novel thermoelectric materials on automotive applications

    Science.gov (United States)

    Brignone, Mauro; Ziggiotti, Alessandro

    2012-06-01

    Despite the fact that thermoelectric (TE) devices are compact, quiet, rugged, stable and very reliable, thermoelectrics have found only niche applications because they are also inefficient (less that 5% conversion efficiency is typical) and costly. The key to more widespread acceptance of thermoelectric is the development of materials that are capable of higher conversion efficiency, but other fundamental materials parameters play a role not less important to open to large applications and markets. In particular the automotive sector requires low materials density, materials made from widely-available pure elements with very large supply chains, non-toxicity of elements and potential compliance with REACH and RoHS obligations and low raw material cost combined with low manufacturing costs. The impact of novel TE materials on automotive application will be described focusing on promising nano magnesium silicide and skutterudites.

  11. Fluid mechanical scaling of impact craters in unconsolidated granular materials

    Science.gov (United States)

    Miranda, Colin S.; Dowling, David R.

    2015-11-01

    A single scaling law is proposed for the diameter of simple low- and high-speed impact craters in unconsolidated granular materials where spall is not apparent. The scaling law is based on the assumption that gravity- and shock-wave effects set crater size, and is formulated in terms of a dimensionless crater diameter, and an empirical combination of Froude and Mach numbers. The scaling law involves the kinetic energy and speed of the impactor, the acceleration of gravity, and the density and speed of sound in the target material. The size of the impactor enters the formulation but divides out of the final empirical result. The scaling law achieves a 98% correlation with available measurements from drop tests, ballistic tests, missile impacts, and centrifugally-enhanced gravity impacts for a variety of target materials (sand, alluvium, granulated sugar, and expanded perlite). The available measurements cover more than 10 orders of magnitude in impact energy. For subsonic and supersonic impacts, the crater diameter is found to scale with the 1/4- and 1/6-power, respectively, of the impactor kinetic energy with the exponent crossover occurring near a Mach number of unity. The final empirical formula provides insight into how impact energy partitioning depends on Mach number.

  12. Silver nanoprisms/silicone hybrid rubber materials and their optical limiting property to femtosecond laser

    Science.gov (United States)

    Li, Chunfang; Liu, Miao; Jiang, Nengkai; Wang, Chunlei; Lin, Weihong; Li, Dongxiang

    2017-08-01

    Optical limiters against femtosecond laser are essential for eye and sensor protection in optical processing system with femtosecond laser as light source. Anisotropic Ag nanoparticles are expected to develop into optical limiting materials for femtosecond laser pulses. Herein, silver nanoprisms are prepared and coated by silica layer, which are then doped into silicone rubber to obtain hybrid rubber sheets. The silver nanoprisms/silicone hybrid rubber sheets exhibit good optical limiting property to femtosecond laser mainly due to nonlinear optical absorption.

  13. Climate change has limited impact on soil-mantled landsliding

    Science.gov (United States)

    Parker, Robert; Hales, Tristram; Mudd, Simon; Grieve, Stuart

    2015-04-01

    Projected increases in future storminess, associated with anthropogenically-driven climate change, are expected to produce an increase in landslide frequency and hazards. This prediction relies on an implicit and poorly tested assumption, that landslide frequency is limited by the effectiveness of landslide triggers (pore-pressure events determined by the intensity and duration of storms). Using an unprecedented field dataset of hillslope soil depths and ages (attained through radiocarbon dating) from the Southern Appalachian Mountains (USA), we show that this assumption is not valid in this landscape. Instead, landslide frequency is limited by rates of soil production and transport processes, which prepare sites for future landsliding. By simulating the evolution of Appalachian hillslopes, we demonstrate that unless climate change can drive an increase in soil production and transport rates, an increase in future storminess will have little effect on long-term landslide frequency, while individual storms will trigger fewer and smaller landslides.

  14. Selecting Materials for Environmental-Friendly Buildings: The Need for Improved Environmental Impact Data

    Directory of Open Access Journals (Sweden)

    Nachawit T.

    2012-01-01

    Full Text Available Buildings of the future need to be more environmental-friendly. Selecting environmentally-benign materials in design stage would partly help achieving such goal. Examination of existing environmental impact data of building materials reveals that the data differ greatly from one source to another. Comparisons of environmental impact values of selected materials are presented. The sources that give rise to data variation are identified and discussed. The applicability of existing data is assessed from the designers’ perspective. Limitations of current practice in data acquisition and presentation are also discussed. It is concluded that existing environmental impact data of building materials are inconsistent and perplexing to designers. An alternative approach to data acquisition and presentation is to break the life cycle of building materials into several phases and to calculate the total impact value as the sum of the impacts of all phases. This would make the determination of the full life cycle value feasible and increase external validity of research results.

  15. Impact tolerance in mussel thread networks by heterogeneous material distribution

    Science.gov (United States)

    Qin, Zhao; Buehler, Markus J.

    2013-07-01

    The Mytilidae, generally known as marine mussels, are known to attach to most substrates including stone, wood, concrete and iron by using a network of byssus threads. Mussels are subjected to severe mechanical impacts caused by waves. However, how the network of byssus threads keeps the mussel attached in this challenging mechanical environment is puzzling, as the dynamical forces far exceed the measured strength of byssus threads and their attachment to the environment. Here we combine experiment and simulation, and show that the heterogeneous material distribution in byssus threads has a critical role in decreasing the effect of impact loading. We find that a combination of stiff and soft materials at an 80:20 ratio enables mussels to rapidly and effectively dissipate impact energy. Notably, this facilitates a significantly enhanced strength under dynamical loading over 900% that of the strength under static loading.

  16. Assessment of the impact of HTSCs on superconducting fault-current limiters

    Energy Technology Data Exchange (ETDEWEB)

    Giese, R.F. [Argonne National Lab., IL (United States); Runde, M. [Energiforsyningens Forskningsinstitutt A/S, Trondheim (Norway)

    1993-03-01

    The possible impact of nitrogen-cooled superconductors on the desip and cost of superconducting fault-current limiters is assessed by considering the technical specifications such devices must meet and by comparing material properties of 77-K and 4-K superconductors. The main advantages of operating superconductors at 77 K are that the refrigeration operating cost is reduced by a factor of up to 25 and the refrigeration capital cost is reduced by a factor of up to 10. The heat capacity is several orders of magnitude Larger at 77 K and at 4 K. This phenomenon increases conductor stability against flux jumps but makes switching from the superconducting to the normal state slow and difficult. Therefore, a high critical current density, probably at least 10{sup 5} A/cm{sup 2}, is required.

  17. Arcjet Testing of Micro-Meteoroid Impacted Thermal Protection Materials

    Science.gov (United States)

    Agrawal, Parul; Munk, Michelle M.; Glaab, Louis J.

    2013-01-01

    There are several harsh space environments that could affect thermal protection systems and in turn pose risks to the atmospheric entry vehicles. These environments include micrometeoroid impact, extreme cold temperatures, and ionizing radiation during deep space cruise, all followed by atmospheric entry heating. To mitigate these risks, different thermal protection material samples were subjected to multiple tests, including hyper velocity impact, cold soak, irradiation, and arcjet testing, at various NASA facilities that simulated these environments. The materials included a variety of honeycomb packed ablative materials as well as carbon-based non-ablative thermal protection systems. The present paper describes the results of the multiple test campaign with a focus on arcjet testing of thermal protection materials. The tests showed promising results for ablative materials. However, the carbon-based non-ablative system presented some concerns regarding the potential risks to an entry vehicle. This study provides valuable information regarding the capability of various thermal protection materials to withstand harsh space environments, which is critical to sample return and planetary entry missions.

  18. Influence Of The Plastic Material Behaviour On The Prediction Of Forming Limits

    Science.gov (United States)

    Vegter, H.; ten Horn, C. H. L. J.; van den Boogaard, A. H.

    2007-05-01

    Prediction of the onset of necking is of large importance in reliability of forming simulation in present automotive industry. Advanced material models require accurate descriptions of the plastic material behaviour including the effect of strain rate. The usual approach for identifying the forming limits in industry is the comparison of a calculated strain map (major against minor strain) with a measured forming limit curve. This approach does not take into account the influence of strain path changes. Prediction of forming limit curves with classical material models can already demonstrate that the forming limits are influenced by this strain path change effect. Including the effect of strain rate on the plastic material behaviour has a strong influence in prediction of onset of instability. Neglecting this effect leads to underestimation of forming capacity of the material in stretch forming parts in particular. The shape of the yield locus will influence the predicted forming limit curves in the region from plane strain to bi-axial. Damage controlled failure will become more important using (advanced) high strength steels. This will affect the stress strain curve at high deformation grades. The work hardening is not only controlled by dislocation interaction, but also by void growth and possible presence of micro-cracks at the interface between the hard en soft phases.

  19. Delivery of Dark Material to Vesta via Carbonaceous Chondritic Impacts

    CERN Document Server

    Reddy, Vishnu; O'Brien, David P; Nathues, Andreas; Cloutis, Edward A; Durda, Daniel D; Bottke, William F; Bhatt, Megha U; Nesvorny, David; Buczkowski, Debra; Scully, Jennifer E C; Palmer, Elizabeth M; Sierks, Holger; Mann, Paul J; Becker, Kris J; Beck, Andrew W; Mittlefehldt, David; Li, Jian-Yang; Gaskell, Robert; Russell, Christopher T; Gaffey, Michael J; McSween, Harry Y; McCord, Thomas B; Combe, Jean-Philippe; Blewett, David

    2012-01-01

    NASA's Dawn spacecraft observations of asteroid (4) Vesta reveal a surface with the highest albedo and color variation of any asteroid we have observed so far. Terrains rich in low albedo dark material (DM) have been identified using Dawn Framing Camera (FC) 0.75 {\\mu}m filter images in several geologic settings: associated with impact craters (in the ejecta blanket material and/or on the crater walls and rims); as flow-like deposits or rays commonly associated with topographic highs; and as dark spots (likely secondary impacts) nearby impact craters. This DM could be a relic of ancient volcanic activity or exogenic in origin. We report that the majority of the spectra of DM are similar to carbonaceous chondrite meteorites mixed with materials indigenous to Vesta. Using high-resolution seven color images we compared DM color properties (albedo, band depth) with laboratory measurements of possible analog materials. Band depth and albedo of DM are identical to those of carbonaceous chondrite xenolith-rich howar...

  20. The Impact of Regulations, Safety Considerations and Physical Limitations on Research Progress at Maximum Biocontainment

    OpenAIRE

    2012-01-01

    We describe herein, limitations on research at biosafety level 4 (BSL-4) containment laboratories, with regard to biosecurity regulations, safety considerations, research space limitations, and physical constraints in executing experimental procedures. These limitations can severely impact the number of collaborations and size of research projects investigating microbial pathogens of biodefense concern. Acquisition, use, storage, and transfer of biological select agents and toxins (BSAT) are ...

  1. Characterization of impact behaviour of armour plate materials

    Directory of Open Access Journals (Sweden)

    Nazimuddin G.

    2012-08-01

    Full Text Available Three armour plate materials, including two steels, namely HHA and Mars 300, and an aluminium alloy 5083, were studied under impact loading to determine their behaviour and the mechanisms of deformation that lead to failure. The experimental testing was carried out using either a direct impact compression Split Hopkinson Bar or a torsion Hopkinson Bar. The impact properties and stress-strain cures were obtained as a function of the impact momentum in compression and the angle of twist in torsion. It was found that at the high strain rates developed in the specimen during the tests, the deformation occurs by the formation of adiabatic shear bands (ASBs which may lead to the formation of cracks within the bands and the ultimate failure of the specimens. It was also found that below a certain impact momentum, the deformation is more uniform and no ASBs are formed. Also, ASBs are more likely to form in the BCC metals such as the two steels while diffuse ASBs associated with plastic flow are exhibited in the 5083 aluminum alloy. Microstructural techniques ranging from optical microscopy to atomic force microscopy (AFM were used to study the topography of the ASBs. Also, modelling of the formation was performed. The results provide a comprehensive understanding of the role of ASBs in the failure of these materials.

  2. Characterization of impact behaviour of armour plate materials

    Science.gov (United States)

    Bassim, M. N.; Bolduc, M.; Nazimuddin, G.; Delorme, J.; Polyzois, I.

    2012-08-01

    Three armour plate materials, including two steels, namely HHA and Mars 300, and an aluminium alloy 5083, were studied under impact loading to determine their behaviour and the mechanisms of deformation that lead to failure. The experimental testing was carried out using either a direct impact compression Split Hopkinson Bar or a torsion Hopkinson Bar. The impact properties and stress-strain cures were obtained as a function of the impact momentum in compression and the angle of twist in torsion. It was found that at the high strain rates developed in the specimen during the tests, the deformation occurs by the formation of adiabatic shear bands (ASBs) which may lead to the formation of cracks within the bands and the ultimate failure of the specimens. It was also found that below a certain impact momentum, the deformation is more uniform and no ASBs are formed. Also, ASBs are more likely to form in the BCC metals such as the two steels while diffuse ASBs associated with plastic flow are exhibited in the 5083 aluminum alloy. Microstructural techniques ranging from optical microscopy to atomic force microscopy (AFM) were used to study the topography of the ASBs. Also, modelling of the formation was performed. The results provide a comprehensive understanding of the role of ASBs in the failure of these materials.

  3. Technology assessment of solar-energy systems. Materials resource and hazardous materials impacts of solar deployment

    Energy Technology Data Exchange (ETDEWEB)

    Schiffman, Y.M.; Tahami, J.E.

    1982-04-01

    The materials-resource and hazardous-materials impacts were determined by examining the type and quantity of materials used in the manufacture, construction, installation, operation and maintenance of solar systems. The materials requirements were compared with US materials supply-and-demand data to determine if potential problems exist in terms of future availability of domestic supply and increased dependence on foreign sources of supply. Hazardous materials were evaluated in terms of public and occupational health hazards and explosive and fire hazards. It is concluded that: (1) although large amounts of materials would be required, the US had sufficient industrial capacity to produce those materials; (2) the postulated growth in solar technology deployment during the period 1995-2000 could cause some production shortfalls in the steel and copper industry; (3) the U.S. could increase its import reliance for certain materials such as silver, iron ore, and copper; (4) however, shifts to other materials such as aluminum and polyvinylchloride could alleviate some of these problems.

  4. Hybrid Nonlinear Optical Materials for Applications in Power Limiting and Photorefractive Devices

    Science.gov (United States)

    2010-03-01

    Final 3. DATES COVERED (From - To) 04/01/2007 to 11/30/2009 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER FA9550-07-1-0307 Hybrid Nonlinear Optical Materials for...Hybrid  Nonlinear   Optical   Materials  for Applications in Power  Limiting and Photorefractive devices      Prime Contract: FA95500710307

  5. Evaluation of geologic materials to limit biological intrusion into low-level radioactive waste disposal sites

    Energy Technology Data Exchange (ETDEWEB)

    Hakonson, T.E.

    1986-02-01

    This report describes the results of a three-year research program to evaluate the performance of selected soil and rock trench cap designs in limiting biological intrusion into simulated waste. The report is divided into three sections including a discussion of background material on biological interactions with waste site trench caps, a presentation of experimental data from field studies conducted at several scales, and a final section on the interpretation and limitations of the data including implications for the user.

  6. Accelerated carbonation testing of mortar with supplementary cement materials. Limitation of the acceleration due to drying

    NARCIS (Netherlands)

    Visser, J.H.M.

    2012-01-01

    In the design stage of a concrete structure, decisions have to be made on how to fulfil the required service life and consequently, what concrete composition to use. Concrete compositions can be chosen on account of known performances but this will limit the choice of compositions and materials to t

  7. DFT Investigation of Osmium Terpyridinyl Complexes as Potential Optical Limiting Materials

    CERN Document Server

    Alok, Shashwat

    2015-01-01

    The development of optical power limiting materials is important to protect individuals or materials from intense laser irradiation. The photophysical behavior of Os(II) polypyridinyl complexes having aromatic hydrocarbon terpyridyl ligands has received considerable attention as systems exhibiting intramolecular energy transfer to yield a long excited states lifetime. Here we present a focused discussion to illustrate the photophysical behavior of transition metal complexes with modified terpyridyl ligands, utilizing density functional theory. Our DFT studies of the excited state behavior of Os(II) complexes containing pyrene-vinylene derived terpyridine (pyr-v-tpy) ligands can be applied to the development of optical limiting materials controlling the laser power at longer wavelength range.

  8. Tensile strength and impact resistance properties of materials used in prosthetic check sockets, copolymer sockets, and definitive laminated sockets

    OpenAIRE

    Maria J. Gerschutz, PhD; Michael L. Haynes, MS; Derek M. Nixon, BS; James M. Colvin, MS

    2011-01-01

    Prosthetic sockets serve as the interface between people with amputations and their prostheses. Although most materials used to make prosthetic sockets have been used for many years, knowledge of these materials' properties is limited, especially after they are subjected to fabrication processes. This study evaluated tensile and impact properties of the current state-of-the-art materials used to fabricate prosthetic check sockets, copolymer sockets, and definitive laminated sockets. Thermolyn...

  9. Synergistically Enhanced Optical Limiting Property of Graphene Oxide Hybrid Materials Functionalized with Pt Complexes.

    Science.gov (United States)

    Liu, Rui; Hu, Jinyang; Zhu, Senqiang; Lu, Jiapeng; Zhu, Hongjun

    2017-09-12

    Recently, graphene-based materials have become well-known nonlinear optical materials for the potential application of laser protection. Two new graphene oxide-platinum  complex (GO-Pt) hybrid materials (GO-Pt-1, GO-Pt-2) have been fabricated through covalent modification and electrostatic adsorption of different Pt complexes with GO. The structural and photophysical properties of the resultant hybrid materials were studied. The nonlinear optical properties and optical power limiting (OPL) performance of Pt complexes, GO, and GO-Pt hybrid materials were investigated by using Z-scan measurements at 532 nm. At the same transmittance, the results illustrate that functionalization of GO makes GO-Pt hybrid materials possess better nonlinear optical properties and OPL performance than individual Pt complexes and GO due to a combination of nonlinear scattering, nonlinear absorption, and photoinduced electron and energy transfer between GO and Pt complex moieties. Furthermore, the nonlinear optics and OPL performance of GO-Pt-2 are better than those of GO-Pt-1, due to not only the excellent optical limiting of Pt-2 and more molecules per area of GO but also the way of combination of Pt-2 and GO.

  10. Limitations and pitfalls of climate change impact analysis on urban rainfall extremes

    DEFF Research Database (Denmark)

    Willems, P.; Olsson, J.; Arnbjerg-Nielsen, Karsten;

    to anthropogenic climate change. Current practices have several limitations and pitfalls, which are important to be considered by trend or climate change impact modellers and users of trend/impact results. Climate change may well be the driver that ensures that changes in urban drainage paradigms are identified...... and suitable solutions implemented. Design and optimization of urban drainage infrastructure considering climate change impacts and co-optimizing with other objectives will become ever more important to keep our cities liveable into the future....

  11. Dental Glass Ionomer Cements as Permanent Filling Materials? – Properties, Limitations and Future Trends

    Directory of Open Access Journals (Sweden)

    Ulrich Lohbauer

    2009-12-01

    Full Text Available Glass ionomer cements (GICs are clinically attractive dental materials that have certain unique properties that make them useful as restorative and luting materials. This includes adhesion to moist tooth structures and base metals, anticariogenic properties due to release of fluoride, thermal compatibility with tooth enamel, biocompatibility and low toxicity. The use of GICs in a mechanically loaded situation, however, has been hampered by their low mechanical performance. Poor mechanical properties, such as low fracture strength, toughness and wear, limit their extensive use in dentistry as a filling material in stress-bearing applications. In the posterior dental region, glass ionomer cements are mostly used as a temporary filling material. The requirement to strengthen those cements has lead to an ever increasing research effort into reinforcement or strengthening concepts.

  12. Friction, impact, and electrostatic discharge sensitivities of energetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Wang, P.S.; Hall, G.F.

    1985-05-31

    Impact, friction, and electrostatic discharge sensitivities of energetic materials (explosives and pyrotechnics) used or manufactured at Mound were tested by the ''one-shot'' method. The Bruceton statistical method was used to derive 50% initiation levels, and the results were compared. The materials tested include: PETN, HMX, Plastic Bonded Explosives (PBX), CP, TATB, RX26BB, RX26BH, barium styphnate, LX-15, LX-16, Ti/KClO/sub 4/, TiH/sub 0.65//KClO/sub 4/, TiH/sub 1.65//KClO/sub 4/, Fe/KClO/sub 4/, TiH/sub 1.75//B/CaCrO/sub 4/, Ti/B/CaCrO/sub 4/, B/CaCrO/sub 4/, TiH/sub 0.65//2B, TiH/sub 0.65//3B, 2Ti/B, TiH/sub 1.67//2B, Ti/2B, TiH/sub 1/67//3B, Ti/B, and Ti/3B. Some samples were investigated for aging effects, physical variables, and the effect of manufacturing paramters on sensitivities. The results show that in both friction and impact tests, CP and barium styphnate are the most sensitive; TiH/sub 1.65/KClO/sub 4/, LX-15, TATB and its related materials are the least sensitive; and other materials such as PETN and HMX are in the mid-range. In the electrostatic tests of Ti-based pyrotechnics, a decrease of sensitivity with increasing hydrogen concentration was observed. 20 refs., 12 figs., 7 tabs.

  13. The analysis of mathematics teachers' learning on algebra function limit material based on teaching experience difference

    Science.gov (United States)

    Ma'rufi, Budayasa, I. Ketut; Juniati, Dwi

    2017-08-01

    The aim of this study was to describe the analysis of mathematics teachers' learning on algebra function limit material based on teaching experience difference. The purpose of this study is to describe the analysis of mathematics teacher's learning on limit algebraic functions in terms of the differences of teaching experience. Learning analysis focused on Pedagogical Content Knowledge (PCK) of teachers in mathematics on limit algebraic functions related to the knowledge of pedagogy. PCK of teachers on limit algebraic function is a type of specialized knowledge for teachers on how to teach limit algebraic function that can be understood by students. Subjects are two high school mathematics teacher who has difference of teaching experience they are one Novice Teacher (NP) and one Experienced Teacher (ET). Data are collected through observation of learning in the class, videos of learning, and then analyzed using qualitative analysis. Teacher's knowledge of Pedagogic defined as a knowledge and understanding of teacher about planning and organizing of learning, and application of learning strategy. The research results showed that the Knowledge of Pedagogy on subject NT in mathematics learning on the material of limit function algebra showed that the subject NT tended to describe procedurally, without explaining the reasons why such steps were used, asking questions which tended to be monotonous not be guiding and digging deeper, and less varied in the use of learning strategies while subject ET gave limited guidance and opportunities to the students to find their own answers, exploit the potential of students to answer questions, provide an opportunity for students to interact and work in groups, and subject ET tended to combine conceptual and procedural explanation.

  14. Potential space debris shield structure using impact-initiated energetic materials composed of polytetrafluoroethylene and aluminum

    Science.gov (United States)

    Wu, Qiang; Zhang, Qingming; Long, Renrong; Zhang, Kai; Guo, Jun

    2016-03-01

    A whipple shield using Al/PTFE (polytetrafluoroethylene) energetic material to protect against space debris is presented. The hypervelocity impact characteristics were investigated experimentally using a two-stage light gas gun at velocities between 3 and 6 km/s. A good protection of the shield was obtained through comparative experiments which used the same bumper areal density. The results showed that the critical projectile diameter can be improved by 28% by contrast with the Christiansen ballistic limit equations. The Al/PTFE energetic material bumper can break up the projectile into smaller, less massive, and slower projectiles due to the combined effect of impact and explosion, thereby producing a sharp rise in the spacecraft protection ability.

  15. The top 50 commodity chemicals: Impact of catalytic process limitations on energy, environment, and economics

    Energy Technology Data Exchange (ETDEWEB)

    Tonkovich, A.L.Y.; Gerber, M.A.

    1995-08-01

    The production processes for the top 50 U.S. commodity chemicals waste energy, generate unwanted byproducts, and require more than a stoichiometric amount of feedstocks. Pacific Northwest Laboratory has quantified this impact on energy, environment, and economics for the catalytically produced commodity chemicals. An excess of 0.83 quads of energy per year in combined process and feedstock energy is required. The major component, approximately 54%, results from low per-pass yields and the subsequent separation and recycle of unreacted feedstocks. Furthermore, the production processes, either directly or through downstream waste treatment steps, release more than 20 billion pounds of carbon dioxide per year to the environment. The cost of the wasted feedstock exceeds 2 billion dollars per year. Process limitations resulting from unselective catalysis and unfavorable reaction thermodynamic constraints are the major contributors to this waste. Advanced process concepts that address these problems in an integrated manner are needed to improve process efficiency, which would reduce energy and raw material consumption, and the generation of unwanted byproducts. Many commodity chemicals are used to produce large volume polymer products. Of the energy and feedstock wasted during the production of the commodity chemicals, nearly one-third and one-half, respectively, represents chemicals used as polymer precursors. Approximately 38% of the carbon dioxide emissions are generated producing polymer feedstocks.

  16. Prevalence and impact of dementia-related functional limitations in the United States, 2001 to 2005.

    Science.gov (United States)

    Arrighi, Henry Michael; McLaughlin, Trent; Leibman, Christopher

    2010-01-01

    These analyses examined the relationship between dementia and comorbid conditions with respect to degree of functional impairment and emotional impact. Analyses were conducted using National Health Interview Survey (2001 through 2005) data from a subset of individuals aged > or =60 years with activity limitations attributed to dementia, senility, or Alzheimer disease compared with those whose limitations were attributed to other conditions. The mean number of limited activities was 6.84 (95% confidence interval: 6.48-7.20) for persons with dementia-related limitations and 4.87 (95% confidence interval: 4.81-4.93) for those with limitations not dementia related. Both groups reported similar prevalence of diabetes, acute myocardial infarction, heart disease, prostate cancer, breast cancer, angina, and emphysema; respondents with dementia-related functional limitations were more likely to report diabetes, depression or anxiety, and vision problems as being related to functional limitations. Persons with dementia-related functional limitations were also more likely than persons with non-dementia-related functional limitations to report feeling sad, hopeless, worthless, nervous, and that "everything is an effort." Improving or maintaining functional independence in patients with dementia will likely require a multifaceted approach across disease states. Additional research will help define the impact of dementia on the development and progression of functional limitations related to comorbidities.

  17. 10 CFR 51.97 - Final environmental impact statement-materials license.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Final environmental impact statement-materials license. 51...-Regulations Implementing Section 102(2) Final Environmental Impact Statements-Materials Licenses § 51.97 Final environmental impact statement—materials license. (a) Independent spent fuel storage installation (ISFSI...

  18. 10 CFR 51.80 - Draft environmental impact statement-materials license.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Draft environmental impact statement-materials license. 51...-Regulations Implementing Section 102(2) Draft Environmental Impact Statements-Materials Licenses § 51.80 Draft environmental impact statement—materials license. (a) The NRC staff will either prepare a draft environmental...

  19. Dynamical properties measurements for asteroid, comet and meteorite material applicable to impact modeling and mitigation calculations

    Energy Technology Data Exchange (ETDEWEB)

    Furnish, M.D.; Boslough, M.B. [Sandia National Labs., Albuquerque, NM (United States); Gray, G.T. III [Los Alamos National Lab., NM (United States); Remo, J.L. [Quantametrics, Inc., St. James, NY (United States)

    1994-07-01

    We describe methods for measuring dynamical properties for two material categories of interest in understanding large-scale extraterrestrial impacts: iron-nickel and underdense materials (e.g. snow). Particular material properties measured by the present methods include Hugoniot release paths and constitutive properties (stress vs. strain). The iron-nickel materials lend themselves well to conventional shock and quasi-static experiments. As examples, a suite of experiments is described including six impact tests (wave profile compression/release) over the stress range 2--20 GPa, metallography, quasi-static and split Hopkinson pressure bar (SHPB) mechanical testing, and ultrasonic mapping and sound velocity measurements. Temperature sensitivity of the dynamic behavior was measured at high and low strain rates. Among the iron-nickel materials tested, an octahedrite was found to have behavior close to that of Armco iron under shock and quasi-static conditions, while an ataxite exhibited a significantly larger quasi-static yield strength than did the octahedrite or a hexahedrite. The underdense materials pose three primary experimental difficulties. First, the samples are friable; they can melt or sublimate during storage, preparation and testing. Second, they are brittle and crushable; they cannot withstand such treatment as traditional machining or launch in a gun system. Third, with increasing porosity the calculated Hugoniot density becomes rapidly more sensitive to errors in wave time-of-arrival measurements. Carefully chosen simulants eliminate preservation (friability) difficulties, but the other difficulties remain. A family of 36 impact tests was conducted on snow and snow simulants at Sandia, yielding reliable Hugoniot and reshock states, but limited release property information. Other methods for characterizing these materials are discussed.

  20. Dynamical properties measurements for asteroid, comet and meteorite material applicable to impact modeling and mitigation calculations

    Science.gov (United States)

    Furnish, M. D.; Boslough, M. B.; Gray, G. T., III; Remo, J. L.

    We describe methods for measuring dynamical properties for two material categories of interest in understanding large-scale extraterrestrial impacts: iron-nickel and underdense materials (e.g. snow). Particular material properties measured by the present methods include Hugoniot release paths and constitutive properties (stress vs. strain). The iron-nickel materials lend themselves well to conventional shock and quasi-static experiments. As examples, a suite of experiments is described including six impact tests (wave profile compression/release) over the stress range 2-20 GPa, metallography, quasi-static and split Hopkinson pressure bar (SHPB) mechanical testing, and ultrasonic mapping and sound velocity measurements. Temperature sensitivity of the dynamic behavior was measured at high and low strain rates. Among the iron-nickel materials tested, an octahedrite was found to have behavior close to that of Armco iron under shock and quasi-static conditions, while an ataxite exhibited a significantly larger quasi-static yield strength than did the octahedrite or a hexahedrite. The underdense materials pose three primary experimental difficulties. First, the samples are friable; they can melt or sublimate during storage, preparation and testing. Second, they are brittle and crushable; they cannot withstand such treatment as traditional machining or launch in a gun system. Third, with increasing porosity the calculated Hugoniot density becomes rapidly more sensitive to errors in wave time-of-arrival measurements. Carefully chosen simulants eliminate preservation (friability) difficulties, but the other difficulties remain. A family of 36 impact tests was conducted on snow and snow simulants at Sandia, yielding reliable Hugoniot and reshock states, but limited release property information. Other methods for characterizing these materials are discussed.

  1. The Impact of Visuals on Nutrition and Health Education Materials

    Directory of Open Access Journals (Sweden)

    Emily Clyatt

    2015-10-01

    Full Text Available Colorado State University Extension (CSUE recently launched a new website, Live Eat Play Colorado (LEP; www.liveeatplay.colostate.edu which promotes traditional CSUE fact sheets as well as new consumer-friendly materials with dense imagery and lower reading levels. LEP has allowed for an increased use of visuals to enrich nutrition and health materials. Appealing visuals serve as tools designed to increase comprehension and memory of health topics (Frisch, Camerini, & Schultz, 2013. Information retention is higher when visuals are combined with text, as opposed to text-only information (Peregrin, 2010. Testing this idea, visuals were placed in the text-only fact sheet, “Nutrition for the Athlete” (231,424 page views in 2014. Google Analytics data revealed that read time increased 23% in the 15 months after visuals were placed compared to the 15 months prior, from an average of 5:32 to 6:50 minutes. The increased read time could suggest that readers are more engaged with information on the webpage and demonstrates the potential positive impact of visuals on web-based education materials. Educators should intentionally select images for fact sheets that will support, reinforce, and/or clarify messages on health topics.

  2. Emerging ferroelectric transistors with nanoscale channel materials: the possibilities, the limitations

    Science.gov (United States)

    Hong, Xia

    2016-03-01

    Combining the nonvolatile, locally switchable polarization field of a ferroelectric thin film with a nanoscale electronic material in a field effect transistor structure offers the opportunity to examine and control a rich variety of mesoscopic phenomena and interface coupling. It is also possible to introduce new phases and functionalities into these hybrid systems through rational design. This paper reviews two rapidly progressing branches in the field of ferroelectric transistors, which employ two distinct classes of nanoscale electronic materials as the conducting channel, the two-dimensional (2D) electron gas graphene and the strongly correlated transition metal oxide thin films. The topics covered include the basic device physics, novel phenomena emerging in the hybrid systems, critical mechanisms that control the magnitude and stability of the field effect modulation and the mobility of the channel material, potential device applications, and the performance limitations of these devices due to the complex interface interactions and challenges in achieving controlled materials properties. Possible future directions for this field are also outlined, including local ferroelectric gate control via nanoscale domain patterning and incorporating other emergent materials in this device concept, such as the simple binary ferroelectrics, layered 2D transition metal dichalcogenides, and the 4d and 5d heavy metal compounds with strong spin-orbit coupling.

  3. Tensile strength and impact resistance properties of materials used in prosthetic check sockets, copolymer sockets, and definitive laminated sockets

    Directory of Open Access Journals (Sweden)

    Maria J. Gerschutz, PhD

    2011-10-01

    Full Text Available Prosthetic sockets serve as the interface between people with amputations and their prostheses. Although most materials used to make prosthetic sockets have been used for many years, knowledge of these materials' properties is limited, especially after they are subjected to fabrication processes. This study evaluated tensile and impact properties of the current state-of-the-art materials used to fabricate prosthetic check sockets, copolymer sockets, and definitive laminated sockets. Thermolyn Rigid and Orfitrans Stiff check socket materials produced significantly lower tensile strength and impact resistance than polyethylene terephthalate glycol (PETG. Copolymer socket materials exhibited greater resistance to impact forces than the check socket materials but lower tensile strengths than PETG. The heated molding processes, for the check socket and copolymer materials, reduced both tensile strength and elongation at break. Definitive laminated sockets were sorted according to fabrication techniques. Nyglass material had significantly higher elongation, indicating a more ductile material than carbon-based laminations. Carbon sockets with pigmented resin had higher tensile strength and modulus at break than nonpigmented carbon sockets. Elongation at yield and elongation at break were similar for both types of carbon-based laminations. The material properties determined in this study provide a foundation for understanding and improving the quality of prosthetic sockets using current fabrication materials and a basis for evaluating future technologies.

  4. Conceptual design of a high-integrity impact limiter for use in shipment of dual-purpose spent-fuel casks

    Energy Technology Data Exchange (ETDEWEB)

    Nickell, R.E. (Applied Science and Technology, Inc., Poway, CA (United States)); Haelsig, R.T.; Hansen, L.J. (Hansen Haelsig Associates, Bellevue, Washington (USA))

    1991-09-01

    A conceptual design for a high-integrity impact limiting system to protect dry metallic spent fuel storage casks during rail transport is proposed. The system is intended to limit the deceleration of the cask during severe rail accidents through three layers of energy-absorbing polyurethane foam material. The crush strengths of the foam is chosen such that the lowest crush strength foam forms the most exterior layer, with the crush strengths increasingly progressively in the two inner layers. The design basis for the external layer of foam is the hypothetical 30-foot free drop impact event prescribed in 10 CFR 71, with a peak steady deceleration limit of about 75 g. The two interior layers absorb up to five times the impact energy of the 30-foot free drop while limiting the decelerations to first 125 g and then to 175 g. The former is felt to be a nominal fuel rod failure threshold, while the latter is at or near the failure level for bolted closure assemblies. These deceleration targets, if met, provide a means for substantially reducing the risk of radioactive material transport. The conceptual design incorporates features for maintaining the integrity of the impact limiter attachment system during severe accidents and enhancing heat dissipation through the impact limiter for short-cooled fuel, through the use of radial aluminum fins. An alternative impact-limiting material -- aluminum honeycomb -- is included in the economic assessment. Both the polyurethane foam and aluminum honeycomb designs appear to meet a cost target of $1.0M, with the polyurethane foam limiter cost estimated at somewhat less than $400K and the aluminum honeycomb cost at somewhat less than $700K. 28 refs., 17 figs., 5 tabs.

  5. Epidemiologic studies of behavioral health following the Deepwater Horizon oil spill: limited impact or limited ability to measure?

    Science.gov (United States)

    Teich, Judith L; Pemberton, Michael R

    2015-01-01

    Two large-scale epidemiologic federal surveys conducted in the Gulf Coast following the Deepwater Horizon oil spill and intended to measure its impact on mental disorders and substance use found less dramatic results than had been anticipated. However, several smaller-scale studies conducted shortly after the spill did find increases in the prevalence of certain psychological problems among individuals surveyed. Previous federal studies conducted following two disasters-the destruction of the World Trade Center (WTC) and Hurricanes Katrina and Rita-found few statistically significant changes in behavioral disorders in the wake of those events, except for individuals displaced from their homes by Katrina for 2 weeks or more. In this commentary, the authors discuss questions raised by these mixed results regarding the limitations of such studies, the behavioral health impact of the Deepwater Horizon spill compared to disasters causing more widespread loss of life and destruction of property, and the ways in which data collection following disasters might be improved to benefit public health planners.

  6. Lightweight Impact-Resistant Composite Materials: Lessons from Mantis Shrimp

    Science.gov (United States)

    Milliron, Garrett Wayne

    Nature has evolved efficient strategies to synthesize complex mineralized structures that exhibit exceptional damage tolerance. One such example is found in the hyper-mineralized hammer-like dactyl clubs of the stomatopods, a group of highly aggressive marine crustaceans. The dactyl clubs from one such species, Odontodactylus Scyllarus, exhibit an impressive set of characteristics adapted for surviving high velocity impacts with the heavily mineralized prey species on which they feed. Consisting of a multi-phase composite of oriented crystalline hydroxyapatite and amorphous calcium phosphate and carbonate, in conjunction with a highly expanded helicoidal organization of the fibrillar chitinous organic matrix, these structures display several effective lines of defense against catastrophic failure during repetitive high energy loading events. The study of this organism and its relatives has lead to design cues, which were incorporated into prototype composite materials designed for applications in aviation, body armor, and entertainment.

  7. Geometric and Algebraic Approaches in the Concept of "Limit" and the Impact of the "Didactic Contract"

    Science.gov (United States)

    Elia, Iliada; Gagatsis, Athanasios; Panaoura, Areti; Zachariades, Theodosis; Zoulinaki, Fotini

    2009-01-01

    The present study explores students' abilities in conversions between geometric and algebraic representations, in problem-solving situations involving the concept of "limit" and the interrelation of these abilities with students' constructed understanding of this concept. An attempt is also made to examine the impact of the…

  8. Electron-impact excitation-autoionization of helium in the S-wave limit

    Energy Technology Data Exchange (ETDEWEB)

    Horner, Daniel A.; McCurdy, C. William; Rescigno, Thomas N.

    2004-10-01

    Excitation of the autoionizing states of helium by electron impact is shown in calculations in the s-wave limit to leave a clear signature in the singly differential cross section for the (e,2e) process. It is suggested that such behavior should be seen generally in (e,2e) experiments on atoms that measure the single differential cross section.

  9. Geometric and Algebraic Approaches in the Concept of "Limit" and the Impact of the "Didactic Contract"

    Science.gov (United States)

    Elia, Iliada; Gagatsis, Athanasios; Panaoura, Areti; Zachariades, Theodosis; Zoulinaki, Fotini

    2009-01-01

    The present study explores students' abilities in conversions between geometric and algebraic representations, in problem-solving situations involving the concept of "limit" and the interrelation of these abilities with students' constructed understanding of this concept. An attempt is also made to examine the impact of the…

  10. Relationship between patient-reported symptoms, limitations in daily activities, and psychological impact in varicose veins.

    Science.gov (United States)

    Mallick, Rajiv; Lal, Brajesh Kumar; Daugherty, Claire

    2017-03-01

    The objective of this study was to evaluate the relationship between patient-reported symptoms, functional limitations, and psychological impact of varicose veins (VVs) vs pathophysiologic mechanism, incorporating demographic and behavioral factors. We conducted a pooled analysis from two clinical studies (Efficacy and Safety Study of Polidocanol Injectable Foam for the Treatment of Saphenofemoral Junction Incompetence [VANISH-1] and Polidocanol Endovenous Microfoam Versus Vehicle for the Treatment of Saphenofemoral Junction Incompetence [VANISH-2]) in patients with VVs (superficial venous reflux only). Health outcomes were classified on the basis of the Wilson-Cleary conceptual framework continuum linking clinical and anatomic factors (Clinical, Etiology, Anatomy, and Pathophysiology [CEAP] clinical class and great saphenous vein [GSV] diameter, respectively) to patient-reported outcomes: Varicose Vein Symptoms Questionnaire (VVSymQ) score; modified Venous Insufficiency Epidemiologic and Economic Study on Quality of Life/Symptoms (m-VEINES-QOL/Sym) limitations in daily activities (functional limitations hereafter) score; and m-VEINES-QOL/Sym psychological impact score. Association of clinical and anatomic categories with each of the patient-reported outcomes was assessed using analysis of variance for statistical significance and standardized mean differences for clinical meaningfulness. Hierarchical regression modeling was applied to evaluate the direct association of the VVSymQ symptom score with the m-VEINES-QOL/Sym functional limitations score and the indirect association with the m-VEINES-QOL/Sym psychological impact score, adjusting for clinical, behavioral, and demographic factors. Among 516 patients, approximately three-fourths were women (mean age, 49 years), approximately 70% were overweight or obese, 42% were C2 and 32% were C3, and 88% reported never or only intermittently wearing compression stockings. VVSymQ (symptom) scores did not vary by GSV

  11. Material specific effects and limitations during ps-laser generation of micro structures

    Science.gov (United States)

    Hildenhagen, J.; Engelhardt, U.; Smarra, M.; Dickmann, K.

    2012-01-01

    The use of picosecond lasers for microstructuring, especially in the combination with scanner optics, leads to undesired effects with increasing ablation depths. The cavity edges slope to a degree ranging between 50° and 85°, depending on the material. With highly reflective substrates, ditches of up to 20% of their total depth can be formed on its ground structure. In certain materials also diverse substructures such as holes, canals, or grooves can be developed. These could impact the precision of the ablation geometry partially. A systematic study of the specific ablation characteristics is needed to achieve a defined depth of the structure. Considering a huge number of influential parameters, an automation of such measurements would be meaningful. For a study of eight different materials (high-alloy steels, copper, titanium, aluminum, PMMA, Al2O3 ceramics, silicon and fused quartz), an industrial ps-laser coupled with a chromatic sensor for distance measurement was used. Hence a direct acquisition of the generated structures as well as an automatic evaluation of the parameters is possible. Furthermore an online quality control and a local post processing can be implemented. In this way the generation of complex structures with a higher precision is possible.

  12. Local dissipation limits the dynamics of impacting droplets on smooth and rough substrates

    CERN Document Server

    Wang, Yuli; Carlson, Andreas

    2016-01-01

    A droplet that impacts onto a solid substrate deforms in a complex dynamics. To extract the principal mechanisms that dominate this dynamics we deploy numerical simulations based on the phase field method. Direct comparison with experiments suggests that a dissipation local to the contact line limits the droplet spreading dynamics and its scaled maximum spreading radius $\\beta_\\mathrm{max}$. By assuming linear response through a drag force at the contact line, our simulations rationalize experimental observations for droplet impact on both smooth and rough substrates, measured through a single contact line friction parameter $\\mu_f$. Moreover, our analysis shows that at low and intermediate impact speeds dissipation at the contact line limits the dynamics and we describe $\\beta_\\mathrm{max}$ by the scaling law $\\beta_\\mathrm{max} \\sim (Re \\mu_\\mathrm{l}/\\mu_f)^{1/2}$ that is a function of the droplet viscosity ($\\mu_\\mathrm{l}$) and its Reynolds number ($Re$).

  13. Football Players' Head-Impact Exposure After Limiting of Full-Contact Practices.

    Science.gov (United States)

    Broglio, Steven P; Williams, Richelle M; O'Connor, Kathryn L; Goldstick, Jason

    2016-07-01

    Sporting organizations limit full-contact football practices to reduce concussion risk and based on speculation that repeated head impacts may result in long-term neurodegeneration. To directly compare head-impact exposure in high school football players before and after a statewide restriction on full-contact practices. Cross-sectional study. High school football field. Participants were varsity football athletes from a single high school. Before the rule change, 26 athletes (age = 16.2 ± 0.8 years, height = 179.6 ± 6.4 cm, weight = 81.9 ± 13.1 kg) participated. After the rule change, 24 athletes (age = 15.9 ± 0.8 years, height = 178.3 ± 6.5 cm, weight = 76.2 ± 11.6 kg) participated. Nine athletes participated in both years of the investigation. Head-impact exposure was monitored using the Head Impact Telemetry System while the athletes participated in football games and practices in the seasons before and after the rule change. Head-impact frequency, location, and magnitude (ie, linear acceleration, rotational acceleration, and Head Impact Telemetry severity profile [HITsp], respectively) were measured. A total of 15 398 impacts (592 impacts per player per season) were captured before the rule change and 8269 impacts (345 impacts per player per season) after the change. An average 42% decline in impact exposure occurred across all players, with practice-exposure declines occurring among linemen (46% decline); receivers, cornerbacks, and safeties (41% decline); and tight ends, running backs (including fullbacks), and linebackers (39% decline). Impact magnitudes remained largely unchanged between the years. A rule change limiting full-contact high school football practices appears to have been effective in reducing head-impact exposure across all players, with the largest reduction occurring among linemen. This finding is likely associated with the rule modification, particularly because the coaching staff and offensive scheme remained consistent, yet how

  14. IMPACLIB: a material property data library for impact analysis of radioactive material transport casks

    Energy Technology Data Exchange (ETDEWEB)

    Ikushima, Takeshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-12-01

    The paper describes the structural data library and graphical program for impact and stress analyses of radioactive material transport casks. Four kinds of material data, structure steels, stainless steels, leads and woods are compiled. These materials are main structural elements of casks. Structural data such as, coefficient of thermal expansion, modulus of longitudinal elasticity, modulus of transverse elasticity, Poisson`s ratio and stress-strain relationship have been tabulated. Main features of IMPACLIB are as follows: (1) data have been tabulated against temperature or strain rate, (2) thirteen kinds of polynominal fitting for stress-strain curve are available, (3) it is capable of graphical representations for structural data and (4) the IMPACLIB is able to be used on not only main frame computers but also work stations (OS UNIX) and personal computers (OS Windows 3.1). In the paper, brief illustration of data library is presented in the first section. The second section presents descriptions of structural data. The third section provides a user`s guide for computer program and input data for the IMPACLIB. (author)

  15. Space Systems - Safety and Compatibility of Materials - Method to Determine the Ignition Susceptibility of Materials or Components to Particle Impact

    Science.gov (United States)

    Hirsch, David B.

    2011-01-01

    The scope of this International Technical Specification is to provide a method to determine the ignition susceptibility of materials and components to particle impact. The method can be used to determine the conditions at which ignition and consumption of a specimen material occurs when impacted by single or multiple particles entrained in a flow of gaseous oxygen (GOX). Alternatively, the method can be used to determine if a specific material or component is subject to ignition and sustained combustion in a given flow environment when impacted by single or multiple particles entrained in a flow of GOX.

  16. Shear adhesion strength of thermoplastic gecko-inspired synthetic adhesive exceeds material limits.

    Science.gov (United States)

    Gillies, Andrew G; Fearing, Ronald S

    2011-09-20

    Natural gecko array wearless dynamic friction has recently been reported for 30,000 cycles on a smooth substrate. Following these findings, stiff polymer gecko-inspired synthetic adhesives have been proposed for high-cycle applications such as robot feet. Here we examine the behavior of high-density polyethylene (HDPE) and polypropylene (PP) microfiber arrays during repeated cycles of engagement on a glass surface, with a normal preload of less than 40 kPa. We find that fiber arrays maintained 54% of the original shear stress of 300 kPa after 10,000 cycles, despite showing a marked plastic deformation of fiber tips. This deformation could be due to shear-induced plastic creep of the fiber tips from high adhesion forces, adhesive wear, or thermal effects. We hypothesize that a fundamental material limit has been reached for these fiber arrays and that future gecko synthetic adhesive designs must take into account the high adhesive forces generated to avoid damage. Although the synthetic material and natural gecko arrays have a similar elastic modulus, the synthetic material does not show the same wear-free dynamic friction as the gecko.

  17. Quantifying the limits of through-plane thermal dissipation in 2D-material-based systems

    Science.gov (United States)

    Yasaei, Poya; Behranginia, Amirhossein; Hemmat, Zahra; El-Ghandour, Ahmed I.; Foster, Craig D.; Salehi-Khojin, Amin

    2017-09-01

    Through-plane thermal transport accounts for a major fraction of heat dissipation from hot-spots in many existing devices made of two-dimensional (2D) materials. In this report, we performed a set of electrical thermometry measurements and 3D finite element analyses to quantify the limits of power dissipation in monolayer graphene, a representative of 2D materials, fabricated on various technologically viable substrates such as chemical vapor deposited (CVD) diamond, tape-casted (sintered) aluminum nitride (AlN), and single crystalline c-plane sapphire as well as silicon with different oxide layers. We demonstrate that the heat dissipation through graphene on AlN substrate near room temperature outperforms those of CVD diamond and other studied substrates, owing to its superior thermal boundary conductance (TBC). At room temperature, our measurements reveal a TBC of 33.5 MW · m-2 · K-1 for graphene on AlN compared to 6.2 MW · m-2 · K-1 on diamond. This study highlights the importance of simultaneous optimization of the interfaces and the substrate and provides a route to maximize the heat removal capability of 2D-material-based devices.

  18. Limit analysis and homogenization of porous materials with Mohr-Coulomb matrix. Part I: Theoretical formulation

    Science.gov (United States)

    Anoukou, K.; Pastor, F.; Dufrenoy, P.; Kondo, D.

    2016-06-01

    The present two-part study aims at investigating the specific effects of Mohr-Coulomb matrix on the strength of ductile porous materials by using a kinematic limit analysis approach. While in the Part II, static and kinematic bounds are numerically derived and used for validation purpose, the present Part I focuses on the theoretical formulation of a macroscopic strength criterion for porous Mohr-Coulomb materials. To this end, we consider a hollow sphere model with a rigid perfectly plastic Mohr-Coulomb matrix, subjected to axisymmetric uniform strain rate boundary conditions. Taking advantage of an appropriate family of three-parameter trial velocity fields accounting for the specific plastic deformation mechanisms of the Mohr-Coulomb matrix, we then provide a solution of the constrained minimization problem required for the determination of the macroscopic dissipation function. The macroscopic strength criterion is then obtained by means of the Lagrangian method combined with Karush-Kuhn-Tucker conditions. After a careful analysis and discussion of the plastic admissibility condition associated to the Mohr-Coulomb criterion, the above procedure leads to a parametric closed-form expression of the macroscopic strength criterion. The latter explicitly shows a dependence on the three stress invariants. In the special case of a friction angle equal to zero, the established criterion reduced to recently available results for porous Tresca materials. Finally, both effects of matrix friction angle and porosity are briefly illustrated and, for completeness, the macroscopic plastic flow rule and the voids evolution law are fully furnished.

  19. The impact of smoking on airflow limitation in subjects with history of asthma and inactive tuberculosis.

    Directory of Open Access Journals (Sweden)

    Hyun Jung Kim

    Full Text Available Although smoking is the most important and modifiable cause of chronic obstructive pulmonary disease (COPD, other risk factors including asthma and tuberculosis (TB are also associated. It is common for COPD patients to have more than one of these risk factors. The aims of this study were to determine the prevalence of airflow limitation (FEV1/FVC<0.7 according to the risk factors and to investigate their impact and interaction in airflow limitation.From the Korean National Health and Nutrition Examination Survey between 2008 and 2012, we analyzed participants over 40 years of age by spirometry, chest radiograph and questionnaire about asthma and smoking history.Of 12,631 participants, 1,548 (12.3% had airflow limitation. The prevalence of airflow limitation in smokers (≥10 pack-year, asthmatics, and those with inactive TB was 23.9%, 32.1%, and 33.6%. The prevalence increased with the number of risk factors: 86.1% had airflow limitation if they had all three risk factors. Impacts of inactive TB and asthma on airflow limitation were equivalent to 47 and 69 pack-years of smoking, respectively. Airflow limitation resulted from lower levels of smoking in those with inactive TB and asthma. A potential interaction between smoking and inactive tuberculosis in the development of airflow limitation was identified (p = 0.054.Asthma and inactive TB lesions increase susceptibility to smoking in the development of airflow limitation. People with these risk factors should be seen as a major target population for anti-smoking campaigns to prevent COPD.

  20. Forty years of experiments on aquatic invasive species: are study biases limiting our understanding of impacts?

    Directory of Open Access Journals (Sweden)

    Mads Thomsen

    2014-06-01

    Full Text Available Invasions by non-native species are a threat to biodiversity because invaders can impact native populations, communities and entire ecosystems. To manage this threat, it is necessary to have a strong mechanistic understanding of how non-native species affect local species and communities. We reviewed 259 published papers (1972–2012 that described field experiments quantifying the impact of aquatic non-native species, to examine whether various types of study biases are limiting this understanding. Our review revealed that invasion impacts had been experimentally quantified for 101 aquatic non-native species, in all major freshwater and marine habitats, on all continents except Antarctica and for most higher taxonomic groupings. Over one-quarter (26% of studies included tests for impacts on local biodiversity. However, despite this extensive research effort, certain taxa, habitats and regions remain poorly studied. For example, of the over one hundred species examined in previous studies, only one was a marine fish and only six were herbivores. Furthermore, over half (53% the studies were from the USA and two-thirds (66% were from experiments conducted in temperate latitudes. By contrast, only 3% of studies were from Africa and <2% from high latitudes. We also found that one-fifth (20% of studies were conducted in estuaries, but only 1% from coral reefs. Finally, we note that the standard procedure of pooling or not reporting non-significant treatments and responses is likely to limit future synthetic advancement by biasing meta-analysis and severely limiting our ability to identify non-native species with none or negligible ecological impacts. In conclusion, a future focus on poorly-studied taxa, habitats and regions, and enhanced reporting of results, should improve our understanding and management of impacts associated with aquatic non-native species.

  1. Life cycle assessment as a method of limitation of a negative environment impact of castings

    Directory of Open Access Journals (Sweden)

    M. Holtzer

    2011-07-01

    Full Text Available Casting production constitutes environmental problems going far beyond the foundry plant area. Applying a notion of the life cycle the input (suppliers side and output factors (clients side can be identified. The foundry plant activities for the environment hazard mitigation can be situated on various stages of the casting life cycle. The environment impact of motorisation castings made of different materials – during the whole life cycle of castings – are discussed in the paper. It starts from the charge material production, then follows via the casting process, car assembly, car exploitation and ends at the car breaking up for scrap.

  2. Impact and Limitations Deriving from Basel II within the Context of the Current Financial Crisis

    Directory of Open Access Journals (Sweden)

    Oana Miruna DĂNILĂ

    2012-06-01

    Full Text Available The Banking sector risk management framework, geared towards maintaining a solid capital adequacy level, has witnessed a permanent evolution, determined by the global economic and financial reality.Basel II has brought an improvement of the risk management framework by adding minimum capital levels corresponding to market and operational risk and by the introduction of internal rating models. However the current crisis has brought forward some adverse effects as well as limitations.This paper analyses the evolution of prudential rules and regulations introduced by Basel II and their impact on the banking system together with outlining certain limitations.

  3. Chemical Footprint Method for Improved Communication of Freshwater Ecotoxicity Impacts in the Context of Ecological Limits

    DEFF Research Database (Denmark)

    Bjørn, Anders; Diamond, Miriam; Birkved, Morten

    2014-01-01

    The ecological footprint method has been successful in communicating environmental impacts of anthropogenic activities in the context of ecological limits. We introduce a chemical footprint method that expresses ecotoxicity impacts from anthropogenic chemical emissions as the dilution needed...... to avoid freshwater ecosystem damage. The indicator is based on USEtox characterization factors with a modified toxicity reference point. Chemical footprint results can be compared to the actual dilution capacity within the geographic vicinity receiving the emissions to estimate whether its ecological...... limit has been exceeded and hence whether emissions can be expected to be environmentally sustainable. The footprint method was illustrated using two case studies. The first was all inventoried emissions from European countries and selected metropolitan areas in 2004, which indicated that the dilution...

  4. On Limitations of the Ultrasonic Characterization of Pieces Manufactured with Highly Attenuating Materials

    Science.gov (United States)

    Ramos, A.; Moreno, E.; Rubio, B.; Calas, H.; Galarza, N.; Rubio, J.; Diez, L.; Castellanos, L.; Gómez, T.

    Some technical aspects of two Spanish cooperation projects, funded by DPI and Innpacto Programs of the R&D National Plan, are discussed. The objective is to analyze the common belief about than the ultrasonic testing in MHz range is not a tool utilizable to detect internal flaws in highly attenuating pieces made of coarse-grained steel. In fact high-strength steels, used in some safe industrial infrastructures of energy & transport sectors, are difficult to be inspected using the conventional "state of the art" in ultrasonic technology, due to their internal microstructures are very attenuating and coarse-grained. It is studied if this inspection difficulty could be overcome by finding intense interrogating pulses and advanced signal processing of the acquired echoes. A possible solution would depend on drastically improving signal-to-noise-ratios, by applying new advances on: ultrasonic transduction, HV electronics for intense pulsed driving of the testing probes, and an "ad-hoc" digital processing or focusing of the received noisy signals, in function of each material to be inspected. To attain this challenging aim on robust steel pieces would open the possibility of obtaining improvements in inspecting critical industrial components made of highly attenuating & dispersive materials, as new composites in aeronautic and motorway bridges, or new metallic alloys in nuclear area, where additional testing limitations often appear.

  5. Transient Structures and Possible Limits of Data Recording in Phase-Change Materials.

    Science.gov (United States)

    Hu, Jianbo; Vanacore, Giovanni M; Yang, Zhe; Miao, Xiangshui; Zewail, Ahmed H

    2015-07-28

    Phase-change materials (PCMs) represent the leading candidates for universal data storage devices, which exploit the large difference in the physical properties of their transitional lattice structures. On a nanoscale, it is fundamental to determine their performance, which is ultimately controlled by the speed limit of transformation among the different structures involved. Here, we report observation with atomic-scale resolution of transient structures of nanofilms of crystalline germanium telluride, a prototypical PCM, using ultrafast electron crystallography. A nonthermal transformation from the initial rhombohedral phase to the cubic structure was found to occur in 12 ps. On a much longer time scale, hundreds of picoseconds, equilibrium heating of the nanofilm is reached, driving the system toward amorphization, provided that high excitation energy is invoked. These results elucidate the elementary steps defining the structural pathway in the transformation of crystalline-to-amorphous phase transitions and describe the essential atomic motions involved when driven by an ultrafast excitation. The establishment of the time scales of the different transient structures, as reported here, permits determination of the possible limit of performance, which is crucial for high-speed recording applications of PCMs.

  6. Exciton size and binding energy limitations in one-dimensional organic materials

    Energy Technology Data Exchange (ETDEWEB)

    Kraner, S., E-mail: stefan.kraner@iapp.de; Koerner, C.; Leo, K. [Institut für Angewandte Photophysik, Technische Universität Dresden, Dresden (Germany); Scholz, R. [Institut für Angewandte Photophysik, Technische Universität Dresden, Dresden (Germany); Dresden Center of Computational Materials Science, Technische Universität Dresden, D-01062 Dresden (Germany); Plasser, F. [Institute for Theoretical Chemistry, University of Vienna, A-1090 Vienna (Austria)

    2015-12-28

    In current organic photovoltaic devices, the loss in energy caused by the charge transfer step necessary for exciton dissociation leads to a low open circuit voltage, being one of the main reasons for rather low power conversion efficiencies. A possible approach to avoid these losses is to tune the exciton binding energy to a value of the order of thermal energy, which would lead to free charges upon absorption of a photon, and therefore increase the power conversion efficiency towards the Shockley-Queisser limit. We determine the size of the excitons for different organic molecules and polymers by time dependent density functional theory calculations. For optically relevant transitions, the exciton size saturates around 0.7 nm for one-dimensional molecules with a size longer than about 4 nm. For the ladder-type polymer poly(benzimidazobenzophenanthroline), we obtain an exciton binding energy of about 0.3 eV, serving as a lower limit of the exciton binding energy for the organic materials investigated. Furthermore, we show that charge transfer transitions increase the exciton size and thus identify possible routes towards a further decrease of the exciton binding energy.

  7. Geological Cartography of Inner Materials of an Impact Crater on Nepenthes Mensae, Mars

    Science.gov (United States)

    Valenciano, A.; de Pablo, M. A.

    2012-03-01

    We present the geological map and a brief description of the materials, its geological history and an approach to their astrobiological and exopaleontological implications from sedimentary materials located into impact crater, in Nepenthes Mensae, Mars.

  8. Limitations and pitfalls of climate change impact analysis on urban rainfall extremes

    DEFF Research Database (Denmark)

    Willems, P.; Olsson, J.; Arnbjerg-Nielsen, Karsten

    to anthropogenic climate change. Current practices have several limitations and pitfalls, which are important to be considered by trend or climate change impact modellers and users of trend/impact results. Climate change may well be the driver that ensures that changes in urban drainage paradigms are identified...... and suitable solutions implemented. Design and optimization of urban drainage infrastructure considering climate change impacts and co-optimizing with other objectives will become ever more important to keep our cities liveable into the future.......Under the umbrella of the IWA/IAHR Joint Committee on Urban Drainage, the International Working Group on Urban Rainfall (IGUR) has reviewed existing methodologies for the analysis of long-term historical and future trends in urban rainfall extremes and their effects on urban drainage systems, due...

  9. Effect of the hardness of welded materials on the position of the lower limit of explosive welding

    Energy Technology Data Exchange (ETDEWEB)

    Zakharenko, I.D.; Zlobin, B.S.

    1984-03-01

    In order to clarify the question of the effect of the hardness of materials on the position of the lower limit in explosive welding, the authors carried out experiments with materials of essentially different hardnesses. (The investigation of the processes that take place near the lower limit of the region of welding is important in helping us to understand the mechanism of the formation of the welded joint. The experiments permit these conclusions: The process of self-purification in the explosive welding of materials of different hardness can take place as a result of the formation of a flow of material from the softer plate alone; and, in calculating the lower limit of the welding region, the H /SUB V/ of the softer material should be substituted in the expression for calculating the critical angle..gamma.. *.

  10. Impact of selected risk factors on expected lifetime without long-standing, limiting illness in Denmark

    DEFF Research Database (Denmark)

    Brønnum-Hansen, Henrik; Juel, Knud; Davidsen, Michael

    2007-01-01

    OBJECTIVE: To estimate the impacts of tobacco smoking, high alcohol consumption, physical inactivity and overweight on expected lifetime with and without long-standing, limiting illness. METHODS: Life tables for each level of exposure to the risk factors were constructed, mainly on the basis......-olds was 9-10 years shorter for heavy smokers than for those who never smoke, and all the lifetime lost would have been without long-standing, limiting illness. Similarly, all 5 years of expected lifetime lost by men with high alcohol consumption would have been without illness. The expected lifetime without...... long-standing, limiting illness was 8-10 years shorter among sedentary than physically active people. Obesity shortened lifetime without illness by 5 years for men and ten years for women. CONCLUSION: The results of this study could be used in health policy-making, as the potential gains in public...

  11. Comparative evaluation of impact and flexural strength of four commercially available flexible denture base materials: an in vitro study.

    Science.gov (United States)

    Abhay, Pande Neelam; Karishma, Shori

    2013-12-01

    Poly-methyl methacrylate is a rigid material. It is generally observed that the impact and flexural strength of this material is not satisfactory and that is reflected in the continuous efforts to improve these mechanical properties. Hence there was a serious need to make another material which could overcome the limitations of the existing materials and could have better properties, like thermoplastic materials. The study was aimed to evaluate and compare the impact strength and the flexural strength of four different flexible denture base materials (thermoplastic denture base resins) with the conventional denture base material (high impact polymethyl-methacrylate). Two, machine made master moulds of metal blocks according to the size of sample holder of the equipment were prepared to test the impact and flexural strength. Total 40 samples, 10 for each group of flexible denture base materials namely: De-flex (Deflex, United Kingdom), Lucitone FRS (Densply, Germany), Valplast (Novoblast, USA), and Bre-flex (Bredent, Germany) in specially designed flask by injection molded process. For different flexible materials, the time, temperature and pressure for injecting the materials were followed as per the manufacturer's instructions. Total 20 samples for control (Trevelon denture base materials) were prepared by compression moulded process, for each test. ANOVA test was applied to calculate p value. Unpaired t test was applied to calculate t-value. Tukey-Kramer multiple test was provided for comparison between the groups for flexural and impact strength. From the statistical analysis, it was found that, the impact strength of Group III (Valplast) was found to be the highest than all other groups and nearer to the control group. Whereas Group IV (Bre-flex) had the maximum flexural strength. The flexural strength of Group I (De-flex) was lowest than all other groups and nearer to control group. The values were found to be statistically significant but clinically non

  12. The impact of regulations, safety considerations and physical limitations on research progress at maximum biocontainment.

    Science.gov (United States)

    Shurtleff, Amy C; Garza, Nicole; Lackemeyer, Matthew; Carrion, Ricardo; Griffiths, Anthony; Patterson, Jean; Edwin, Samuel S; Bavari, Sina

    2012-12-01

    We describe herein, limitations on research at biosafety level 4 (BSL-4) containment laboratories, with regard to biosecurity regulations, safety considerations, research space limitations, and physical constraints in executing experimental procedures. These limitations can severely impact the number of collaborations and size of research projects investigating microbial pathogens of biodefense concern. Acquisition, use, storage, and transfer of biological select agents and toxins (BSAT) are highly regulated due to their potential to pose a severe threat to public health and safety. All federal, state, city, and local regulations must be followed to obtain and maintain registration for the institution to conduct research involving BSAT. These include initial screening and continuous monitoring of personnel, controlled access to containment laboratories, accurate and current BSAT inventory records. Safety considerations are paramount in BSL-4 containment laboratories while considering the types of research tools, workflow and time required for conducting both in vivo and in vitro experiments in limited space. Required use of a positive-pressure encapsulating suit imposes tremendous physical limitations on the researcher. Successful mitigation of these constraints requires additional time, effort, good communication, and creative solutions. Test and evaluation of novel vaccines and therapeutics conducted under good laboratory practice (GLP) conditions for FDA approval are prioritized and frequently share the same physical space with important ongoing basic research studies. The possibilities and limitations of biomedical research involving microbial pathogens of biodefense concern in BSL-4 containment laboratories are explored in this review.

  13. The Impact of Regulations, Safety Considerations and Physical Limitations on Research Progress at Maximum Biocontainment

    Directory of Open Access Journals (Sweden)

    Jean Patterson

    2012-12-01

    Full Text Available We describe herein, limitations on research at biosafety level 4 (BSL-4 containment laboratories, with regard to biosecurity regulations, safety considerations, research space limitations, and physical constraints in executing experimental procedures. These limitations can severely impact the number of collaborations and size of research projects investigating microbial pathogens of biodefense concern. Acquisition, use, storage, and transfer of biological select agents and toxins (BSAT are highly regulated due to their potential to pose a severe threat to public health and safety. All federal, state, city, and local regulations must be followed to obtain and maintain registration for the institution to conduct research involving BSAT. These include initial screening and continuous monitoring of personnel, controlled access to containment laboratories, accurate and current BSAT inventory records. Safety considerations are paramount in BSL-4 containment laboratories while considering the types of research tools, workflow and time required for conducting both in vivo and in vitro experiments in limited space. Required use of a positive-pressure encapsulating suit imposes tremendous physical limitations on the researcher. Successful mitigation of these constraints requires additional time, effort, good communication, and creative solutions. Test and evaluation of novel vaccines and therapeutics conducted under good laboratory practice (GLP conditions for FDA approval are prioritized and frequently share the same physical space with important ongoing basic research studies. The possibilities and limitations of biomedical research involving microbial pathogens of biodefense concern in BSL-4 containment laboratories are explored in this review.

  14. The evaluation of Spanish environmental impact. Costs and limitations; La evaluacion de impacto ambiental en Espana. Coste y limitaciones

    Energy Technology Data Exchange (ETDEWEB)

    Canto, S.; Riera, P.; Borrego, A.

    2009-07-01

    The environmental impact assessment applies to new investments in public infrastructure and in industrial activities. The latter accounts for most of the environmental impact studies undertaken in Spain. This evaluation tool has a number of limitations and weaknesses, both in the analysis and its implementation. This article discusses some of these limitations, including the private cost of the process. (Author) 14 refs.

  15. Assessment of the impact of HTSCs on superconducting fault-current limiters. [High Temperature SuperConductors (HTSCs)

    Energy Technology Data Exchange (ETDEWEB)

    Giese, R.F. (Argonne National Lab., IL (United States)); Runde, M. (Energiforsyningens Forskningsinstitutt A/S, Trondheim (Norway))

    1993-01-01

    The possible impact of nitrogen-cooled superconductors on the desip and cost of superconducting fault-current limiters is assessed by considering the technical specifications such devices must meet and by comparing material properties of 77-K and 4-K superconductors. The main advantages of operating superconductors at 77 K are that the refrigeration operating cost is reduced by a factor of up to 25 and the refrigeration capital cost is reduced by a factor of up to 10. The heat capacity is several orders of magnitude Larger at 77 K and at 4 K. This phenomenon increases conductor stability against flux jumps but makes switching from the superconducting to the normal state slow and difficult. Therefore, a high critical current density, probably at least 10[sup 5] A/cm[sup 2], is required.

  16. Material properties limiting the performance of CZT gamma-ray detectors

    Energy Technology Data Exchange (ETDEWEB)

    Bolotnikov,A.E.; Babalola, S.; Camarda, G. S.; Cui, Y.; Egarievwe, S. U.; Hossain, A.; Yang, G.; James, R. B.

    2009-03-16

    CdZnTe (CZT) nuclear radiation detectors are advanced sensors that utilize innovative technologies developed for wide band-gap semiconductor industry and microelectronics. They open opportunities for new types of room-temperature operating, field deployable instruments that provide accurate identification of potential radiological threats and timely awareness for both the civilian and military communities. Room-temperature radiation detectors are an emerging technology that relies on the use of high-quality CZT crystals whose availability is currently limited by material non-uniformities and the presence of extended defects. To address these issues, which are most critical to CZT sensor developments, we developed X-ray mapping and IR transmission microscopy systems to characterize both CZT crystals and devices. Since a customized system is required for such X-ray measurements, we use synchrotron radiation beams available at BNL's National Synchrotron Light Source. A highly-collimated and high-intensity X-ray beam supports measurements of areas as small as 10 x 10 {micro}m{sup 2}, and allowed us to see fluctuations in collected charge over the entire area of the detector in a reasonable time. The IR microscopy system allows for 3D visualization of Te inclusions and other extended defects. In this paper, we describe the experimental techniques used in our measurements and typical results obtained from CZT samples produced by different suppliers.

  17. Investigation on low velocity impact resistance of SMA composite material

    Science.gov (United States)

    Hu, Dianyin; Zhang, Long; Wang, Rongqiao; Zhang, Xiaoyong

    2016-04-01

    A method to improve low velocity impact resistance of aeroengine composite casing using shape memory alloy's properties of shape memory(SM) and super-elasticity(SE) is proposed in this study. Firstly, a numerical modeling of SMA reinforced composite laminate under low velocity impact load with impact velocity of 10 m/s is established based on its constitutive model implemented by the VUMAT subroutine of commercial software ABAQUS. Secondly, the responses of SMA composite laminate including stress and deflection distributions were achieved through transient analysis under low velocity impact load. Numerical results show that both peak stress and deflection values of SMA composite laminate are less than that without SMA, which proves that embedding SMA into the composite structure can effectively improve the low velocity impact performance of composite structure. Finally, the influence of SM and SE on low velocity impact resistance is quantitatively investigated. The values of peak stress and deflection of SMA composite based on SM property decrease by 18.28% and 9.43% respectively, compared with those without SMA, instead of 12.87% and 5.19% based on SE. In conclusion, this proposed model described the impact damage of SMA composite structure and turned to be a more beneficial method to enhance the impact resistance by utilizing SM effect.

  18. Regional climate model simulations indicate limited climatic impacts by operational and planned European wind farms.

    Science.gov (United States)

    Vautard, Robert; Thais, Françoise; Tobin, Isabelle; Bréon, François-Marie; Devezeaux de Lavergne, Jean-Guy; Colette, Augustin; Yiou, Pascal; Ruti, Paolo Michele

    2014-01-01

    The rapid development of wind energy has raised concerns about environmental impacts. Temperature changes are found in the vicinity of wind farms and previous simulations have suggested that large-scale wind farms could alter regional climate. However, assessments of the effects of realistic wind power development scenarios at the scale of a continent are missing. Here we simulate the impacts of current and near-future wind energy production according to European Union energy and climate policies. We use a regional climate model describing the interactions between turbines and the atmosphere, and find limited impacts. A statistically significant signal is only found in winter, with changes within ±0.3 °C and within 0-5% for precipitation. It results from the combination of local wind farm effects and changes due to a weak, but robust, anticyclonic-induced circulation over Europe. However, the impacts remain much weaker than the natural climate interannual variability and changes expected from greenhouse gas emissions.

  19. Impact Testing for Materials Science at NASA - MSFC

    Science.gov (United States)

    Sikapizye, Mitch

    2010-01-01

    The Impact Testing Facility (ITF) at NASA - Marshall Space Flight Center is host to different types of guns used to study the effects of high velocity impacts. The testing facility has been and continues to be utilized for all NASA missions where impact testing is essential. The Facility has also performed tests for the Department of Defense, other corporations, as well as universities across the nation. Current capabilities provided by Marshall include ballistic guns, light gas guns, exploding wire gun, and the Hydrometeor Impact Gun. A new plasma gun has also been developed which would be able to propel particles at velocities of 20km/s. This report includes some of the guns used for impact testing at NASA Marshall and their capabilities.

  20. Impact of Bilingual Education Programs on Limited English Proficient Students and Their Peers

    DEFF Research Database (Denmark)

    Daysal, N. Meltem; Chin, Aimee; Imberman, Scott

    2013-01-01

    Texas requires a school district to offer bilingual education when its enrollment of limited English proficient (LEP) students in a particular elementary grade and language is twenty or higher. Using school panel data, we find a significant increase in the probability that a district provides...... bilingual education above this 20-student cutoff. Using this discontinuity as an instrument for district bilingual education provision, we find that providing bilingual education programs (relative to providing only English as a Second Language programs) does not significantly impact the standardized test...... scores of students with Spanish as their home language (comprised primarily of ever-LEP students). However, we find significant positive impacts on non-LEP students’ achievement, which indicates that education programs for LEP students have spillover effects to non-LEP students....

  1. Pedestrian evacuation in view and hearing limited condition: The impact of communication and memory

    Science.gov (United States)

    Xue, Shuqi; Jia, Bin; Jiang, Rui; Shan, Jingjing

    2016-09-01

    This paper studies pedestrian evacuation in view and hearing limited condition based on the social force approach. It is assumed that there are two types of pedestrians: Informed individuals know the exit location whereas uninformed individuals do not. The uninformed individuals can communicate with the informed ones within their perceptual fields, thus learning to know and memorize the exit location. We consider cases with and without communication/memory. The simulations show communication and memory are able to enhance the evacuation efficiency. We also investigate the impact of communication on the efficiency of an emergency exit.

  2. Impact and residual fatigue behavior of ARALL and AS6/5245 composite materials

    Science.gov (United States)

    Johnson, W. S.

    1986-01-01

    Aramide fiber reinforced aluminum laminates (ARALL) represent a cross between resin matrix composites and metals. The purpose of this study was to evaluate the impact sensitivity of this concept. Two types of ARALL (7075 aluminum prestrained and 2024 aluminum not prestrained) were tested through static indentation and the results compared to sheet 2024-T3 and 7075-T6 aluminum alloys. A state-of-the-art composite (AS6/5245) was also tested and compared to the ARALL. Further, the two types of ARALL material and the composite were dynamically impacted at two energy levels and fatigue tested to determine residual fatigue strength. Both forms of the ARALL material had worse impact resistance than monolithic sheet aluminum. The ARALL material made with 2024-T3 aluminum had better impact resistance than did the laminates made with 7075-T6 aluminum. The ARALL materials are at least equal to the composite material in impact damage resistance and are better for impact detection. The composite material has higher residual fatigue strength after impact than the ARALL material and is 25 percent lighter. The prestraining of the ARALL greatly reduces the fatigue growth of impact damage.

  3. Impact test on natural fiber reinforced polymer composite materials

    Directory of Open Access Journals (Sweden)

    D. Chandramohan

    2013-06-01

    Full Text Available In this research, natural fibers like Sisal (Agave sisalana, Banana (Musa sepientum & Roselle (Hibiscus sabdariffa , Sisal and banana (hybrid , Roselle and banana (hybrid and Roselle and sisal (hybrid are fabricated with bio epoxy resin using molding method. In this work, impact strength of Sisal and banana (hybrid, Roselle and banana (hybridand Roselle and sisal (hybrid composite at dry and wet conditions were studied. Impact test were conducted izod impact testing machine. In this work micro structure of the specimens are scanned by the Scanning Electron Microscope.

  4. Drop Impact on Textile Material: Effect of Fabric Properties

    Directory of Open Access Journals (Sweden)

    Romdhani Zouhaier

    2014-09-01

    Full Text Available This paper presents an experimental study of impact of water drop on a surface in a spreading regime with no splashing. Three surfaces were studied: virgin glass, coating film and woven cotton fabric at different construction parameters. All experiments were carried out using water drop with the same free fall high. Digidrop with high-resolution camera is used to measure the different parameters characterising this phenomenon. Results show an important effect of the height of the free fall on the drop profile and the spreading behaviour. An important drop deformation at the surface impact was observed. Then, fabric construction as the weft count deeply affects the drop impact. For plain weave, an increase of weft count causes a decrease in penetration and increase in the spreading rate. The same result was obtained for coated fabric. Therefore, the impact energy was modified and the drop shape was affected, which directly influenced the spreading rate.

  5. Impact resistance of hybrid composite fan blade materials

    Science.gov (United States)

    Friedrich, L. A.

    1974-01-01

    Improved resistance to foreign object damage was demonstrated for hybrid composite simulated blade specimens. Transply metallic reinforcement offered additional improvement in resistance to gelatin projectile impacts. Metallic leading edge protection permitted equivalent-to-titanium performance of the hybrid composite simulated blade specimen for impacts with 1.27 cm and 2.54 cm (0.50 and 1.00 inch) diameter gelatin spheres.

  6. Assessment of arsenic speciation and bioaccessibility in mine-impacted materials

    Science.gov (United States)

    Mine-impacted materials were collected from Victoria, Australia and categorized into three source materials; tailings (n = 35), calcinated (n = 10) and grey slimes (n = 5). Arsenic (As) concentrations in these materials varied over several orders of magnitude (30-47,000 mg kg

  7. Chemical footprint method for improved communication of freshwater ecotoxicity impacts in the context of ecological limits.

    Science.gov (United States)

    Bjørn, Anders; Diamond, Miriam; Birkved, Morten; Hauschild, Michael Zwicky

    2014-11-18

    The ecological footprint method has been successful in communicating environmental impacts of anthropogenic activities in the context of ecological limits. We introduce a chemical footprint method that expresses ecotoxicity impacts from anthropogenic chemical emissions as the dilution needed to avoid freshwater ecosystem damage. The indicator is based on USEtox characterization factors with a modified toxicity reference point. Chemical footprint results can be compared to the actual dilution capacity within the geographic vicinity receiving the emissions to estimate whether its ecological limit has been exceeded and hence whether emissions can be expected to be environmentally sustainable. The footprint method was illustrated using two case studies. The first was all inventoried emissions from European countries and selected metropolitan areas in 2004, which indicated that the dilution capacity was likely exceeded for most European countries and all landlocked metropolitan areas. The second case study indicated that peak application of pesticides alone was likely to exceed Denmark's freshwater dilution capacity in 1999-2011. The uncertainty assessment showed that better spatially differentiated fate factors would be useful and pointed out other major sources of uncertainty and some opportunities to reduce these.

  8. Materials selection and design of products with low environmental impact

    Energy Technology Data Exchange (ETDEWEB)

    Ashby, M.F. [Engineering Design Centre, Cambridge Univ. (United Kingdom). Dept. of Engineering, Engineering Design Centre; Wegst, U.G.K. [Max-Planck-Inst. fuer Metallforschung, Stuttgart (Germany)

    2002-06-01

    The creation, use and disposal of any engineering product carry with it an environmental burden. Materials contribute to it in their production, use and disposal of these products. The minimisation of the environmental burden for the whole life-time requires the selection of materials that-without compromising product quality-create less toxic by-products, allow a longer life, are more easily recycled, are lighter and less energy intensive, and that, where possible, use renewable or non-critical resources. The research described here aims at the environmentally-conscious selection of materials early in the design process. It is illustrated by a case study on materials substitution for lightweight cars. (orig.)

  9. On the behaviour characterization of metallic cellular materials under impact loading

    Science.gov (United States)

    Fang, Dai-Ning; Li, Yu-Long; Zhao, Han

    2010-12-01

    This paper reviews the common mechanical features of the metallic cellular material under impact loading as well as the characterization methods of such behaviours. The main focus is on the innovations of various testing methods at impact loading rates. Following aspects were discussed in details. (1) The use of soft nylon Hopkinson/Kolsky bar for an enhanced measuring accuracy in order to assess if there is a strength enhancement or not for this class of cellular materials under moderate impact loading; (2) The use of digital image correlations to determine the strain fields during the tests to confirm the existence of a pseudo-shock wave propagation inside the cellular material under high speed impact; (3) The use of new combined shear compression device to determine the loading envelop of cellular materials under impact multiaxial loadings.

  10. IMPACT OF NUCLEAR MATERIAL DISSOLUTION ON VESSEL CORROSION

    Energy Technology Data Exchange (ETDEWEB)

    Mickalonis, J.; Dunn, K.; Clifton, B.

    2012-10-01

    Different nuclear materials require different processing conditions. In order to maximize the dissolver vessel lifetime, corrosion testing was conducted for a range of chemistries and temperature used in fuel dissolution. Compositional ranges of elements regularly in the dissolver were evaluated for corrosion of 304L, the material of construction. Corrosion rates of AISI Type 304 stainless steel coupons, both welded and non-welded coupons, were calculated from measured weight losses and post-test concentrations of soluble Fe, Cr and Ni.

  11. Low-impact friction materials for brake pads

    OpenAIRE

    2016-01-01

    State-of-the-art friction materials for applications in disc brake systems are constituted by composite materials, specifically formulated to ensure proper friction and wear performances, under the sliding contact conditions of braking events. The bases of typical friction compound formulations usually include 10 to 30 different components bonded with a polymeric binder cross-linked in situ. Main requests to be fulfilled during braking are an adequate friction efficiency and enough mechanical...

  12. A multicriteria approach for environmental impact assessment of contaminated materials

    Energy Technology Data Exchange (ETDEWEB)

    Cagigal, E.; Bonilla, A.; Urzelai, A. [LABEIN, Bilbao (Spain); Diaz, A.; Gorostiza, I. [GAIKER Technological Centre, Zamudio (Spain)

    2003-07-01

    This project aims to develop a method for the environmental assessment of contaminated materials. The core of the study is based on the ecotoxicological characterisation of the mobile/bioavailable fraction of the materials. In order to achieve this objective several assays were carried out divided into mobility/bioavailability tests and toxicity tests on mobile fractions. Mobility procedures involved batch leaching tests, column tests and sequential extraction tests. MicrotoxTM tests were employed for the measurement of the toxicological response of the extracted fractions. Toxicity tests on solid phase (Microtox SP and worms) were also carried out in order to assess correlation between both toxicity responses. This combination of leaching/toxicity tests provides a fast/low cost procedure for the ecotoxicological characterisation and the study of potential hazards associated to contaminated materials. In addition, an ecological risk assessment of the contaminated materials was carried out comparing chemical results with bibliographical toxicity data. According to obtained information, a stepwise methodology for the environmental risk assessment of contaminated materials was proposed. This protocol could be a very useful tool for the evaluation of potential risks for the ecosystems due to the presence of contaminated materials.

  13. Dynamic impact of granular material on a vertical obstacle

    Science.gov (United States)

    Rossi, Giulia; Armanini, Aronne; Larcher, Michele

    2017-04-01

    Debris flows are rapid to very rapid flows, made up of a high concentrated mixture of water and sediments. These types of flow are catastrophic natural phenomena affecting mountain areas and causing several property damages and loss of lives. The mitigation of these phenomena is then fundamental: the check dams are among the main structural countermeasures. A crucial aspect in the definition of the design criteria for these structures is the analysis of the impact force exerted by a debris flow on them. From a scientific point of view, the state of art in this field still has aspects that are not fully clear. There are two main approaches adopted: the first one considers the force of dynamic impact exerted on a structure proportional to the hydrostatic pressure. However, from a theoretical point of view, this approach is not so reliable, since the hydrodynamic nature of the phenomenon probably induces pressures on the structure higher than the hydrostatic values. On the other hand, the second approach assumes the force of the dynamic impact proportional to the square of the velocity of the flow, considering the dynamic nature of the impact. According to Armanini and Scotton (1992), two main types of impact may occur. The first type is characterized by the formation of a reflected wave after the impact, which propagates upstream. A convincing theoretical solution of this problem is achieved through the application of the conservation of mass and momentum equations with respect to a volume control that moves with the reflected wave (Armanini 2009) under the hypothesis of homogeneous fluid. The second type of impact consists of a complete deviation of the flow along the vertical obstacle, assuming a jet-like behavior. The previous theoretical scheme cannot be applied in this situation, but it must be suitably modified. In order to better understand the kinematic characteristics of the phenomenon, the debris flow dynamic impact against a vertical wall has been studied

  14. Impacts Of Passive Removal Materials On Indoor Air Quality

    DEFF Research Database (Denmark)

    Darling, Erin; Cros, Clement; Wargocki, Pawel;

    2011-01-01

    a continuous acceptability scale. Materials were either new carpet that was aired out for three weeks, clay plaster applied to gypsum wallboard that was aired out for up to one month, both materials, or neither. Perceived Air Quality (PAQ) assessed by the panel was most acceptable and concentrations...... of aldehydes were lowest when only clay plaster or both clay plaster and carpet were in the chambers without ozone. The least acceptable PAQ and the highest concentrations of aldehydes were observed when carpet and ozone were present together; addition of clay plaster for this condition improved PAQ...

  15. 49 CFR 173.421 - Excepted packages for limited quantities of Class 7 (radioactive) materials.

    Science.gov (United States)

    2010-10-01

    ... exceed 0.005 mSv/hour (0.5 mrem/ hour); (3) The nonfixed (removable) radioactive surface contamination on... 7 (radioactive) materials. 173.421 Section 173.421 Transportation Other Regulations Relating to... MATERIALS REGULATIONS SHIPPERS-GENERAL REQUIREMENTS FOR SHIPMENTS AND PACKAGINGS Class 7 (Radioactive...

  16. Impact of nitrogen deposition on forest and lake food webs in nitrogen-limited environments.

    Science.gov (United States)

    Meunier, Cédric L; Gundale, Michael J; Sánchez, Irene S; Liess, Antonia

    2016-01-01

    Increased reactive nitrogen (Nr ) deposition has raised the amount of N available to organisms and has greatly altered the transfer of energy through food webs, with major consequences for trophic dynamics. The aim of this review was to: (i) clarify the direct and indirect effects of Nr deposition on forest and lake food webs in N-limited biomes, (ii) compare and contrast how aquatic and terrestrial systems respond to increased Nr deposition, and (iii) identify how the nutrient pathways within and between ecosystems change in response to Nr deposition. We present that Nr deposition releases primary producers from N limitation in both forest and lake ecosystems and raises plants' N content which in turn benefits herbivores with high N requirements. Such trophic effects are coupled with a general decrease in biodiversity caused by different N-use efficiencies; slow-growing species with low rates of N turnover are replaced by fast-growing species with high rates of N turnover. In contrast, Nr deposition diminishes below-ground production in forests, due to a range of mechanisms that reduce microbial biomass, and decreases lake benthic productivity by switching herbivore growth from N to phosphorus (P) limitation, and by intensifying P limitation of benthic fish. The flow of nutrients between ecosystems is expected to change with increasing Nr deposition. Due to higher litter production and more intense precipitation, more terrestrial matter will enter lakes. This will benefit bacteria and will in turn boost the microbial food web. Additionally, Nr deposition promotes emergent insects, which subsidize the terrestrial food web as prey for insectivores or by dying and decomposing on land. So far, most studies have examined Nr -deposition effects on the food web base, whereas our review highlights that changes at the base of food webs substantially impact higher trophic levels and therefore food web structure and functioning. © 2015 John Wiley & Sons Ltd.

  17. Delivery of Organic Material and Water through Asteroid Impacts

    NARCIS (Netherlands)

    Mueller, Michael; Frantseva, Kateryna; van der Tak, Floris; Helmich, Frank P.

    2014-01-01

    Meteorites, specifically carbonaceous chondrites, are frequently invoked as the primary source of Earth's water and organic materials, crucial ingredients for the formation of life. We have started developing a dynamical model of the delivery of their parent bodies, primitive low-albedo asteroids, f

  18. Delivery of Organic Material and Water through Asteroid Impacts

    NARCIS (Netherlands)

    Mueller, Michael; Frantseva, Kateryna; van der Tak, Floris; Helmich, Frank P.

    2014-01-01

    Meteorites, specifically carbonaceous chondrites, are frequently invoked as the primary source of Earth's water and organic materials, crucial ingredients for the formation of life. We have started developing a dynamical model of the delivery of their parent bodies, primitive low-albedo asteroids,

  19. Impacts Of Passive Removal Materials On Indoor Air Quality

    DEFF Research Database (Denmark)

    Darling, Erin; Cros, Clement; Wargocki, Pawel

    2011-01-01

    Indoor air quality (IAQ) was determined in the presence of eight combinations of building materials with and without ozone. Air samples were collected in twin 30 m3 chambers to assess the C5 to C10 aldehyde content of the air while a panel of 18 to 23 human subjects assessed air quality using a c...

  20. A procedure for estimating site specific derived limits for the discharge of radioactive material to the atmosphere

    CERN Document Server

    Hallam, J; Jones, J A

    1983-01-01

    Generalised Derived Limits (GDLs) for the discharge of radioactive material to the atmosphere are evaluated using parameter values to ensure that the exposure of the critical group is unlikely to be underestimated significantly. Where the discharge is greater than about 5% of the GDL, a more rigorous estimate of the derived limit may be warranted. This report describes a procedure for estimating site specific derived limits for discharges of radioactivity to the atmosphere taking into account the conditions of the release and the location and habits of the exposed population. A worksheet is provided to assist in carrying out the required calculations.

  1. Drop Impact on Textile Material: Effect of Fabric Properties

    OpenAIRE

    2014-01-01

    This paper presents an experimental study of impact of water drop on a surface in a spreading regime with no splashing. Three surfaces were studied: virgin glass, coating film and woven cotton fabric at different construction parameters. All experiments were carried out using water drop with the same free fall high. Digidrop with high-resolution camera is used to measure the different parameters characterising this phenomenon. Results show an important effect of the height of the free fall on...

  2. Characterization of Carbonaceous Material from the Sudbury Impact Structure Using Raman Microspectroscopy

    Science.gov (United States)

    Wright, A. J.; Parnell, J.; Ames, D. E.

    2008-03-01

    Samples from the 1.85 Ga Sudbury impact structure have been analyzed using Raman microspectroscopy in order to characterize the carbonaceous material and to investigate the relationship between the carbonaceous strata associated with the structure.

  3. Impact of packaging material and storage time on olive oil quality ...

    African Journals Online (AJOL)

    Impact of packaging material and storage time on olive oil quality. ... appreciated for its characteristic flavor and its biological and nutritional value which are strongly related to the quality. ... EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

  4. Characterization of ferrimagnetic and dielectric materials with a rectangular waveguide-method, limits of validity

    Energy Technology Data Exchange (ETDEWEB)

    Nader, Chadi [Laboratoire Dispositifs et Optoelectronique et Microondes, Universite Jean Monnet, 23 rue Paul Michelon, 42023 St Etienne (France)]. E-mail: chadi.nader@univ-st-etienne.fr; Bayard, Bernard [Laboratoire Dispositifs et Optoelectronique et Microondes, Universite Jean Monnet, 23 rue Paul Michelon, 42023 St Etienne (France); Siblini, Ali [Laboratoire Dispositifs et Optoelectronique et Microondes, Universite Jean Monnet, 23 rue Paul Michelon, 42023 St Etienne (France); Sauviac, Bruno [Laboratoire Dispositifs et Optoelectronique et Microondes, Universite Jean Monnet, 23 rue Paul Michelon, 42023 St Etienne (France); Jammal, Ahmad [Laboratoire d' Electronique et d' Electrotechnique, Universite Libanaise, Liban (Libya)

    2005-04-15

    The development of passive components in the microwave range for telecommunication applications is a major focus for the next years. Some microwave passive components (such as circulators, isolators, etc.) still use magnetic materials. It is then necessary to characterize the electromagnetic properties of such materials, their scattering behaviours and to eventually highlight a non-reciprocal propagation. A method for the dielectric and magnetic characterization of multi-layer materials in the X-band (8.2-12.4 GHz) is presented as well as its reliability and its domain of validity. It allows to determine the elements of the permeability tensor of ferrite sample.

  5. Predicting the behavioural impact of transcranial direct current stimulation: issues and limitations

    Directory of Open Access Journals (Sweden)

    Archy Otto De Berker

    2013-10-01

    Full Text Available The transcranial application of weak currents to the human brain has enjoyed a decade of success, providing a simple and powerful tool for non-invasively altering human brain function. However, our understanding of current delivery and its impact upon neural circuitry leaves much to be desired. We argue that the credibility of conclusions drawn with tDCS is contingent upon realistic explanations of how tDCS works, and that our present understanding of tDCS limits the technique’s use to localize function in the human brain. We outline two central issues where progress is required: the localization of currents, and predicting their functional consequence. We encourage experimenters to eschew simplistic explanations of mechanisms of transcranial current stimulation. We suggest the use of individualized current modelling, together with computational neurostimulation to inform mechanistic frameworks in which to interpret the physiological impact of tDCS. We hope that through mechanistically richer descriptions of current flow and action, insight into the biological processes by which transcranial currents influence behaviour can be gained, leading to more effective stimulation protocols and empowering conclusions drawn with tDCS.

  6. Impact of Packing and Processing Technique on Mechanical Properties of Acrylic Denture Base Materials

    Directory of Open Access Journals (Sweden)

    Touraj Nejatian

    2015-04-01

    Full Text Available The fracture resistance of polymethylmethacrylate (PMMA as the most popular denture base material is not satisfactory. Different factors can be involved in denture fracture. Among them, flexural fatigue and impact are the most common failure mechanisms of an acrylic denture base. It has been shown that there is a correlation between the static strength and fatigue life of composite resins. Therefore, the transverse strength of the denture base materials can be an important indicator of their service life. In order to improve the fracture resistance of PMMA, extensive studies have been carried out; however, only a few promising results were achieved, which are limited to some mechanical properties of PMMA at the cost of other properties. This study aimed at optimizing the packing and processing condition of heat-cured PMMA as a denture base resin in order to improve its biaxial flexural strength (BFS. The results showed that the plain type of resin with a powder/monomer ratio of 2.5:1 or less, packed conventionally and cured in a water bath for 2 h at 95 °C provides the highest BFS. Also, it was found that the performance of the dry heat processor is inconsistent with the number of flasks being loaded.

  7. STEAM EXPLOSION : PROCESS AND IMPACT ON LIGNOCELLULOSIC MATERIAL

    OpenAIRE

    Jacquet, Nicolas; Vanderghem, Caroline; Danthine, Sabine; Blecker, Christophe; Paquot, Michel

    2012-01-01

    Steam explosion is a thermomechanochemical process which allows the breakdown of lignocellulosic structural components by steam heating, hydrolysis of glycosidic bonds by organic acid formed during the process and shearing forces due to the expansion of the moisture. The process is composed of two distinct stages: vapocracking and explosive decompression. Cumul effects of both phases include modification of the physical properties of the material (specific surface area, water retention capaci...

  8. Environmental impacts of construction materials use: a life cycle perspective

    CSIR Research Space (South Africa)

    Ampofo-Anti, N

    2009-02-01

    Full Text Available , fibreboard, cellulose products, steel, aluminium frames, appliances, wire, paint, solvents, plate glass, carpet 3 On-site construction Foundation and site earthwork, concrete pouring, structural framing, roofing, mechanical... reusable materials, knock-down, site clearing, disposal PRE-USE PHASE USE-PHASE EOL 5 mining, growing/harvesting quarrying and felling is a source of air pollutants, solid waste, polluted water run-off and noise, vibration and odour. The processing...

  9. Impact of structural design criteria on first wall surface heat flux limit

    Energy Technology Data Exchange (ETDEWEB)

    Majumdar, S. [Argonne National Lab., IL (United States)

    1998-09-01

    The irradiation environment experienced by the in-vessel components of fusion reactors presents structural design challenges not envisioned in the development of existing structural design criteria such as the ASME Code or RCC-MR. From the standpoint of design criteria, the most significant issues stem from the irradiation-induced changes in material properties, specifically the reduction of ductility, strain hardening capability, and fracture toughness with neutron irradiation. Recently, Draft 7 of the ITER structural design criteria (ISDC), which provide new rules for guarding against such problems, was released for trial use by the ITER designers. The new rules, which were derived from a simple model based on the concept of elastic follow up factor, provide primary and secondary stress limits as functions of uniform elongation and ductility. The implication of these rules on the allowable surface heat flux on typical first walls made of type 316 stainless steel and vanadium alloys are discussed.

  10. Impact of Channel Asymmetry on Base Station Cooperative Transmission with Limited Feedback

    CERN Document Server

    Hou, Xueying

    2010-01-01

    Base station (BS) cooperative transmission, also known as coordinated multi-point transmission (CoMP), is an effective way to avoid inter-cell interference in universal frequency reuse cellular systems. To gain the promised benefit, however, huge feedback overhead is in demand to gather the channel information. In this paper, we analyze the impact of channel asymmetry, which is inherent in CoMP systems, on downlink BS cooperative transmission with limited feedback. We analyze the per-user rate loss of a multi-user CoMP system led by quantization. Per-cell quantization of multicell channels is considered, which quantizes the local channel and cross channel separately and is more feasible in practice. From both the analytical and simulation results, we provide a whole picture on various critical factors that lead to the performance loss. Specifically, we show that the per user rate loss led by limited feedback depends on the location of its paired users, except for relying on its own signal to noise ratio and t...

  11. Will nutrient and light limitation prevent eutrophication in an anthropogenically-impacted coastal lagoon?

    Science.gov (United States)

    Domingues, Rita B.; Guerra, Cátia C.; Barbosa, Ana B.; Galvão, Helena M.

    2017-06-01

    The Ria Formosa coastal lagoon (southern Portugal) is a highly productive and valuable temperate ecosystem, subjected to strong anthropogenic impacts and highly vulnerable to climate change. The main goal of this work is to understand ecosystem susceptibility to eutrophication, by evaluating the isolated and combined effects of nutrient (N, P and Si) and light enrichments on phytoplankton growth and community composition during autumn, winter and spring. Microcosms of natural phytoplankton collected in the lagoon were subjected to different nutrient and light treatments and incubated in situ for 48 h. Nutrient consumption, and phytoplankton growth and community structure were evaluated using spectrophotometric methods, and inverted and epifluorescence microscopy. Diatoms were the only group potentially limited by nitrogen, and only during spring. Increased nutrient consumptions were observed for all nutrient additions in all seasons, not associated with phytoplankton growth, suggesting that luxury consumption was used to build up intracellular nutrient pools. Responses to light enrichment were inconsistent among phytoplankton groups, probably due to a high taxonomic seasonal variability. Positive responses to light enrichment were mostly observed during winter. Negative synergistic interactions between nutrients and light were also observed. We conclude that eutrophication is currently not a problem in the Ria Formosa coastal lagoon, but future nutrient enrichments may lead to accelerated growth of specific functional groups and species, if light is not limiting.

  12. Impact Response of Granular Material at Global and Meso Scales

    Science.gov (United States)

    2013-02-01

    nO/ displays curendy valid OMB DOrUOI nunber. PlEASE DO NOT Rl!TVRN YOUR FORM TO THE .A BOY £ ADDRESS. 1. REPORT DATE (00-MM-YYYY) 12. REPORT TYPE...by flash x-ray. To observe variations in impact-induced pressure inside the sand target, we developed thin pressure sensors that are embedded in... flash -X-ray system was integrated with the target chamber of the gas gun. To measure the cavity size opened up by the projectile in the target, a

  13. CISBAT 2007 - Environmental impacts of construction (ecological materials)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    This is the eighth part of the proceedings of the 2007 CISBAT conference on Renewables in a changing climate, held in Lausanne, Switzerland. On the subject of Environmental impacts of construction the following oral contributions are summarised: 'Nanostructured coatings for active solar facades' and 'Sol-gel organic-inorganic hybrids as binders for TISS paints'. Further groups of presentations at the conference are reported on in separate database records. An index of authors completes the proceedings.

  14. Using Lunar Impact Glasses to Inform the Amount of Organic Material Delivered to the Early Earth

    Science.gov (United States)

    Nguyen, Pham; Zellner, Nicolle

    2017-01-01

    The delivery of organic material via comets and asteroids during the early history of Earth plays an important role in some theories about the origin of life on Earth. Given the close proximity of the Moon to the Earth, the Moon’s impact history can be used to estimate the amount of organic material delivered to the early Earth. Analysis of lunar impact glasses, derived from energetic impacts on the Moon, provide valuable data that can be used to interpret the Moon’s impact flux. Here we present the results of a study of the non-volatile lithophile element compositions of over 500 impact glass samples from the Apollo 14, 16, and 17 landing sites, along with associated ages of a subset of them. Our analyses show that many of the impact glasses possess compositions exotic to the local regolith in which they were found. Coupled with their ages, these glasses suggest material transport from distant regions of the Moon and may allow an estimate of the number of lunar (and terrestrial) impactors in a given time period. These results have important implications for constraining the Moon’s impact flux and also the amount of organic material delivered to the early Earth. Results of our preliminary study, which investigates the amounts of organic material delivered by comets and asteroids to the Moon (and Earth), will be presented.

  15. Using Nondestructive Portable X-ray Fluorescence Spectrometers on Stone, Ceramics, Metals, and Other Materials in Museums: Advantages and Limitations.

    Science.gov (United States)

    Tykot, Robert H

    2016-01-01

    Elemental analysis is a fundamental method of analysis on archaeological materials to address their overall composition or identify the source of their geological components, yet having access to instrumentation, its often destructive nature, and the time and cost of analyses have limited the number and/or size of archaeological artifacts tested. The development of portable X-ray fluorescence (pXRF) instruments over the past decade, however, has allowed nondestructive analyses to be conducted in museums around the world, on virtually any size artifact, producing data for up to several hundred samples per day. Major issues have been raised, however, about the sensitivity, precision, and accuracy of these devices, and the limitation of performing surface analysis on potentially heterogeneous objects. The advantages and limitations of pXRF are discussed here regarding archaeological studies of obsidian, ceramics, metals, bone, and painted materials.

  16. Recovery of microfields in fiber-reinforced composite materials: Principles and limitations

    Science.gov (United States)

    Ritchey, Andrew J.

    A detailed investigation of the limitations and errors induced by modeling a composite layer composed of straight carbon fibers embedded in an epoxy matrix as an homogenous layer with Cauchy effective moduli is performed. Specifically, the material system studied has IM7 carbon fibers arranged in a square array and bonded together with 8552 epoxy resin (IM7/8552). The finite element method is used to study the effect of free surfaces on the local elastic fields in 0°, 45° and 90° laminae, in which as many as 256 individual fibers are modeled. Through these analyses, it is shown that a micro-boundary layer, analogous to the macro-boundary layer observed in composite laminates, is developed at the microlevel. Additionally, [0/90]s and [90/0]s laminates are studied to investigate the joint action of the macro- and micro-boundary layers. Unless otherwise noted, fiber volume fractions of Vƒ=0.20 and Vƒ=0.65 are selected and the domains are subjected to uniform axial extension. Although this study is done for a highly idealized geometry (i.e. with a single material system and under a simple loading condition) the principles of periodicity, symmetry and antisymmetry used to efficiently perform a direct numerical simulation with a large number of fiber inclusions is general, and can be applied to more complicated geometries and boundary conditions. The purpose of the current work is to be the first step in a building block approach to understanding the interaction of multiple scales in fiber-reinforced composites through direct numerical simulations. The main part of the current manuscript focuses on the characterization of a micro-boundary layer that develops in fiber reinforced composite layers. This phenomena results from the changing constraints on the constituent phases as a result of discontinuities, such as free surfaces or ply interfaces. The effect is most pronounced in laminae that have a fiber termination intersecting a free surface, and appears to be

  17. Impact of Coaching and Mentoring in the Nigeria Liquefied Natural Gas Company Limited, Bonny

    Directory of Open Access Journals (Sweden)

    Agwu Mba Okechukwu

    2015-02-01

    Full Text Available The paper examined the impact of coaching and mentoring in the Nigeria liquefied natural gas company limited, bonny. The research question addressed the extent at which improved employees job performance/reduced employees turnover  is influenced by the implementation of coaching and mentoring program in the Nigeria liquefied natural gas company limited, bonny. It views coaching and mentoring as learning relationships that improve employees’ job skills and develop their potentials for better performance. The core aspect of the study is the use of cross-sectional survey research design in generating the required primary data. The place of study is the bonny industrial area of the Nigeria liquefied natural gas company while the duration of study is between December 2013 and November 2014. A sample of 370(184 Direct staff, 150 Contract staff and 36 Seconded staff respondents determined at 5% level of significance for sample error, using Yamane’s formula, was selected from a population of 4,895 employees using stratified random sampling method for the purpose of questionnaire administration. The results indicated that implementation of coaching and mentoring  program in the Nigeria liquefied natural gas company limited bonny, to a large extent influenced improved employees’ performance(74.32% response rate and reduced employees turnover(67.57% response rate.It therefore recommends among others: sustenance of the current coaching and mentoring program, regular appraisal of employees job skill requirements, continuous staff development, regular improvement of employees’ condition of service and sustenance of current team building efforts/ incentive scheme. Keywords: Coaching and mentoring, employees’ performance, employees’ turnover,organizational performance, NLNG bonny. 

  18. Know your limits? Climate extremes impact the range of Scots pine in unexpected places.

    Science.gov (United States)

    Julio Camarero, J; Gazol, Antonio; Sancho-Benages, Santiago; Sangüesa-Barreda, Gabriel

    2015-11-01

    Although extreme climatic events such as drought are known to modify forest dynamics by triggering tree dieback, the impact of extreme cold events, especially at the low-latitude margin ('rear edge') of species distributional ranges, has received little attention. The aim of this study was to examine the impact of one such extreme cold event on a population of Scots pine (Pinus sylvestris) along the species' European southern rear-edge range limit and to determine how such events can be incorporated into species distribution models (SDMs). A combination of dendrochronology and field observation was used to quantify how an extreme cold event in 2001 in eastern Spain affected growth, needle loss and mortality of Scots pine. Long-term European climatic data sets were used to contextualize the severity of the 2001 event, and an SDM for Scots pine in Europe was used to predict climatic range limits. The 2001 winter reached record minimum temperatures (equivalent to the maximum European-wide diurnal ranges) and, for trees already stressed by a preceding dry summer and autumn, this caused dieback and large-scale mortality. Needle loss and mortality were particularly evident in south-facing sites, where post-event recovery was greatly reduced. The SDM predicted European Scots pine distribution mainly on the basis of responses to maximum and minimum monthly temperatures, but in comparison with this the observed effects of the 2001 cold event at the southerly edge of the range limit were unforeseen. The results suggest that in order to better forecast how anthropogenic climate change might affect future forest distributions, distribution modelling techniques such as SDMs must incorporate climatic extremes. For Scots pine, this study shows that the effects of cold extremes should be included across the entire distribution margin, including the southern 'rear edge', in order to avoid biased predictions based solely on warmer climatic scenarios. © The Author 2015. Published by

  19. A bipotential-based limit analysis and homogenization of ductile porous materials with non-associated Drucker-Prager matrix

    Science.gov (United States)

    Cheng, Long; Jia, Yun; Oueslati, Abdelbacet; de Saxcé, Géry; Kondo, Djimedo

    2015-04-01

    In Gurson's footsteps, different authors have proposed macroscopic plastic models for porous solid with pressure-sensitive dilatant matrix obeying the normality law (associated materials). The main objective of the present paper is to extend this class of models to porous materials in the context of non-associated plasticity. This is the case of Drucker-Prager matrix for which the dilatancy angle is different from the friction one, and classical limit analysis theory cannot be applied. For such materials, the second last author has proposed a relevant modeling approach based on the concept of bipotential, a function of both dual variables, the plastic strain rate and stress tensors. On this ground, after recalling the basic elements of the Drucker-Prager model, we present the corresponding variational principles and the extended limit analysis theorems. Then, we formulate a new variational approach for the homogenization of porous materials with a non-associated matrix. This is implemented by considering the hollow sphere model with a non-associated Drucker-Prager matrix. The proposed procedure delivers a closed-form expression of the macroscopic bifunctional from which the criterion and a non-associated flow rule are readily obtained for the porous material. It is shown that these general results recover several available models as particular cases. Finally, the established results are assessed and validated by comparing their predictions to those obtained from finite element computations carried out on a cell representing the considered class of materials.

  20. The impact of roofing material on building energy performance

    Science.gov (United States)

    Badiee, Ali

    The last decade has seen an increase in the efficient use of energy sources such as water, electricity, and natural gas as well as a variety of roofing materials, in the heating and cooling of both residential and commercial infrastructure. Oil costs, coal and natural gas prices remain high and unstable. All of these instabilities and increased costs have resulted in higher heating and cooling costs, and engineers are making an effort to keep them under control by using energy efficient building materials. The building envelope (that which separates the indoor and outdoor environments of a building) plays a significant role in the rate of building energy consumption. An appropriate architectural design of a building envelope can considerably lower the energy consumption during hot summers and cold winters, resulting in reduced HVAC loads. Several building components (walls, roofs, fenestration, foundations, thermal insulation, external shading devices, thermal mass, etc.) make up this essential part of a building. However, thermal insulation of a building's rooftop is the most essential part of a building envelope in that it reduces the incoming "heat flux" (defined as the amount of heat transferred per unit area per unit time from or to a surface) (Sadineni et al., 2011). Moreover, more than 60% of heat transfer occurs through the roof regardless of weather, since a roof is often the building surface that receives the largest amount of solar radiation per square annually (Suman, and Srivastava, 2009). Hence, an argument can be made that the emphasis on building energy efficiency has influenced roofing manufacturing more than any other building envelope component. This research project will address roofing energy performance as the source of nearly 60% of the building heat transfer (Suman, and Srivastava, 2009). We will also rank different roofing materials in terms of their energy performance. Other parts of the building envelope such as walls, foundation

  1. Modeling Lightning Impact Thermo-Mechanical Damage on Composite Materials

    Science.gov (United States)

    Muñoz, Raúl; Delgado, Sofía; González, Carlos; López-Romano, Bernardo; Wang, De-Yi; LLorca, Javier

    2014-02-01

    Carbon fiber-reinforced polymers, used in primary structures for aircraft due to an excellent strength-to-weight ratio when compared with conventional aluminium alloy counterparts, may nowadays be considered as mature structural materials. Their use has been extended in recent decades, with several aircraft manufacturers delivering fuselages entirely manufactured with carbon composites and using advanced processing technologies. However, one of the main drawbacks of using such composites entails their poor electrical conductivity when compared with aluminium alloy competitors that leads to lightning strikes being considered a significant threat during the service life of the aircraft. Traditionally, this problem was overcome with the use of a protective copper/bronze mesh that added additional weight and reduced the effectiveness of use of the material. Moreover, this traditional sizing method is based on vast experimental campaigns carried out by subjecting composite panels to simulated lightning strike events. While this method has proven its validity, and is necessary for certification of the structure, it may be optimized with the aid provided by physically based numerical models. This paper presents a model based on the finite element method that includes the sources of damage observed in a lightning strike, such as thermal damage caused by Joule overheating and electromagnetic/acoustic pressures induced by the arc around the attachment points. The results of the model are compared with lightning strike experiments carried out in a carbon woven composite.

  2. Quality and Knowledge Content in Music Activities in Preschool: The Impact of Human Materiality Combinations

    Science.gov (United States)

    Zimmerman Nilsson, Marie-Helene; Holmberg, Kristina

    2017-01-01

    Traditionally, pedagogical research has been child centered, where materialities often have been considered as objects and tools. However, in recent posthuman research, attempts have been made to consider human materiality combinations to have impact on pedagogical activities in preschool, but to a large extent music as an issue has been…

  3. Quality and Knowledge Content in Music Activities in Preschool: The Impact of Human Materiality Combinations

    Science.gov (United States)

    Zimmerman Nilsson, Marie-Helene; Holmberg, Kristina

    2017-01-01

    Traditionally, pedagogical research has been child centered, where materialities often have been considered as objects and tools. However, in recent posthuman research, attempts have been made to consider human materiality combinations to have impact on pedagogical activities in preschool, but to a large extent music as an issue has been…

  4. Impact of reduced dose limits on NRC licensed activities. Major issues in the implementation of ICRP/NCRP dose limit recommendations: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Meinhold, C.B. [Brookhaven National Lab., Upton, NY (United States)

    1995-05-01

    This report summarizes information required to estimate, at least qualitatively, the potential impacts of reducing occupational dose limits below those given in 10 CFR 20 (Revised). For this study, a questionnaire was developed and widely distributed to the radiation protection community. The resulting data together with data from existing surveys and sources were used to estimate the impact of three dose-limit options; 10 mSv yr{sup {minus}1} (1 rem yr{sup {minus}1}), 20 mSv yr{sup {minus}1} (2 rem yr{sup {minus}1}), and a combination of an annual limit of 50 mSv yr{sup {minus}1} (5 rem yr{sup {minus}1}) coupled with a cumulative limit, in rem, equal to age in years. Due to the somewhat small number of responses and the lack of data in some specific areas, a working committee of radiation protection experts from a variety of licensees was employed to ensure the exposure data were representative. The following overall conclusions were reached: (1) although 10 mSv yr{sup {minus}1} is a reasonable limit for many licensees, such a limit could be extraordinarily difficult to achieve and potentially destructive to the continued operation of some licensees, such as nuclear power, fuel fabrication, and medicine; (2) twenty mSv yr{sup {minus}1} as a limit is possible for some of these groups, but for others it would prove difficult. (3) fifty mSv yr{sup {minus}1} and age in 10s of mSv appear reasonable for all licensees, both in terms of the lifetime risk of cancer and severe genetic effects to the most highly exposed workers, and the practicality of operation.

  5. Limiting the impact of light pollution on human health, environment and stellar visibility.

    Science.gov (United States)

    Falchi, Fabio; Cinzano, Pierantonio; Elvidge, Christopher D; Keith, David M; Haim, Abraham

    2011-10-01

    Light pollution is one of the most rapidly increasing types of environmental degradation. Its levels have been growing exponentially over the natural nocturnal lighting levels provided by starlight and moonlight. To limit this pollution several effective practices have been defined: the use of shielding on lighting fixture to prevent direct upward light, particularly at low angles above the horizon; no over lighting, i.e. avoid using higher lighting levels than strictly needed for the task, constraining illumination to the area where it is needed and the time it will be used. Nevertheless, even after the best control of the light distribution is reached and when the proper quantity of light is used, some upward light emission remains, due to reflections from the lit surfaces and atmospheric scatter. The environmental impact of this "residual light pollution", cannot be neglected and should be limited too. Here we propose a new way to limit the effects of this residual light pollution on wildlife, human health and stellar visibility. We performed analysis of the spectra of common types of lamps for external use, including the new LEDs. We evaluated their emissions relative to the spectral response functions of human eye photoreceptors, in the photopic, scotopic and the 'meltopic' melatonin suppressing bands. We found that the amount of pollution is strongly dependent on the spectral characteristics of the lamps, with the more environmentally friendly lamps being low pressure sodium, followed by high pressure sodium. Most polluting are the lamps with a strong blue emission, like Metal Halide and white LEDs. Migration from the now widely used sodium lamps to white lamps (MH and LEDs) would produce an increase of pollution in the scotopic and melatonin suppression bands of more than five times the present levels, supposing the same photopic installed flux. This increase will exacerbate known and possible unknown effects of light pollution on human health, environment

  6. Access to Nonbook Materials: The Limits of Subject Indexing for Visual and Aural Languages.

    Science.gov (United States)

    Svenonius, Elaine

    1994-01-01

    Examines some nonbook materials with respect to an aboutness model of indexing, showing that there are instances that defy subject indexing. These occur not so much because of the nature of the medium but because it is being used for nondocumentary purposes or because the subject referenced is nonlexical. (Contains 20 references.) (KRN)

  7. Non-Local Analysis of Forming Limits of Ductile Material Considering Void Growth

    Institute of Scientific and Technical Information of China (English)

    Youngsuk Kim

    2003-01-01

    The current study performed a finite element analysis of the strain localization behavior of a voided ductile material using a non-local plasticity formulation in which the yield strength depends on both an equivalent plastic strain measurement (hardening parameter) and Laplacian equivalent. The introduction of gradient terms to the yield function was found to play an important role in simulating the strain localization behavior of the voided ductile material. The effect of the mesh size and characteristic length on the strain localization were also investigated. An FEM simulation based on the proposed non-local plasticity revealed that the load-strain curves of the voided ductile material subjected to plane strain tension converged to one curve, regardless of the mesh size. In addition, the results using non-local plasticity also exhibited that the dependence of the deformation behavior of the material on the mesh size was much less sensitive than that with classical local plasticity and could be successfully eliminated through the introduction of a large value for the characteristic length.

  8. Testing the limits of freedom of contract: the commercialization of reproductive materials and services.

    Science.gov (United States)

    Trebilcock, M; Martin, M; Lawson, A; Lewis, P

    1994-01-01

    This article examines the cases for and against commercializing, or "commodifying," reproductive materials and services. Using a supply/demand third-party framework, three basic scenarios in which commercial-exchange relationships may be possible--exchange of gametes and zygotes, exchange of gestational services, and exchange of fetal material--and the major parties of interest, or stakeholders, are identified. The study sketches the liberal, essentialist, and radical contingency theories that shape the debate over the commercialization of reproductive materials and services. The article then attempts to derive some basic governing principles that reflect as much common ground as possible amongst these various normative perspectives, while recognizing that complete reconciliation is impossible. Taken together, these principles are designed to reflect a strategy of "constrained commodification," where commercialization or commodification, that is, financial remuneration, plays a relatively neutral role in the utilization of reproductive materials and services. In light of these principles, the article concludes by sketching legal and regulatory regimes with respect to the exchange of gametes and zygotes, gestational services, and fetal tissue.

  9. Theory and experiments characterizing hypervelocity impact plasmas on biased spacecraft materials

    Science.gov (United States)

    Lee, Nicolas; Close, Sigrid; Goel, Ashish; Lauben, David; Linscott, Ivan; Johnson, Theresa; Strauss, David; Bugiel, Sebastian; Mocker, Anna; Srama, Ralf

    2013-03-01

    Space weather including solar activity and background plasma sets up spacecraft conditions that can magnify the threat from hypervelocity impacts. Hypervelocity impactors include both meteoroids, traveling between 11 and 72 km/s, and orbital debris, with typical impact speeds of 10 km/s. When an impactor encounters a spacecraft, its kinetic energy is converted over a very short timescale into energy of vaporization and ionization, resulting in a small, dense plasma. This plasma can produce radio frequency (RF) emission, causing electrical anomalies within the spacecraft. In order to study this phenomenon, we conducted ground-based experiments to study hypervelocity impact plasmas using a Van de Graaff dust accelerator. Iron projectiles ranging from 10-16 g to 10-11 g were fired at speeds of up to 70 km/s into a variety of target materials under a range of surface charging conditions representative of space weather effects. Impact plasmas associated with bare metal targets as well as spacecraft materials were studied. Plasma expansion models were developed to determine the composition and temperature of the impact plasma, shedding light on the plasma dynamics that can lead to spacecraft electrical anomalies. The dependence of these plasma properties on target material, impact speed, and surface charge was analyzed. Our work includes three major results. First, the initial temperature of the impact plasma is at least an order of magnitude lower than previously reported, providing conditions more favorable for sustained RF emission. Second, the composition of impact plasmas from glass targets, unlike that of impact plasmas from tungsten, has low dependence on impact speed, indicating a charge production mechanism that is significant down to orbital debris speeds. Finally, negative ion formation has a strong dependence on target material. These new results can inform the design and operation of spacecraft in order to mitigate future impact-related space weather

  10. Study of Detecting Impact Damage for Composite Material Based on Intelligent Sensor

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A system of impact damage detection for composite material structures by using an intelligent sensor embedded in composite material is described.In the course of signal processing,wavelet transform has the exceptional property of temporal frequency localization, whereas Kohonen artificial neural networks have excellent characteristics of self-learning and fault-tolerance. By combining the merits of abstracting time-frequency domain eigenvalues and improving the ratio of signal to noise in this system,impact damage in composite material can be properly recognized.

  11. Hypervelocity impact on brittle materials of semi-infinite thickness: fracture morphology related to projectile diameter

    Science.gov (United States)

    Taylor, Emma A.; Kay, Laurie; Shrine, Nick R. G.

    Hypervelocity impact on brittle materials produces features not observed on ductile targets. Low fracture toughness and high yield strength produce a range of fracture morphologies including cracking, spallation and shatter. For sub-mm diameter projectiles, impact features are characterised by petaloid spallation separated by radial cracks. The conchoidal or spallation diameter is a parameter in current cratering equations. An alternative method for interpreting hypervelocity impacts on glass targets of semi-infinite thickness is tested against impact data produced using the Light Gas Gun (LGG) facility at the University of Kent at Canterbury (UKC), U.K. Spherical projectiles of glass and other materials with diameters 30-300 μm were fired at ~5 km s^-1 at a glass target of semi-infinite thickness. The data is used to test a power law relationship between projectile diameter and crack length. The results of this work are compared with published cratering/spallation equations for brittle materials.

  12. A research of material input and environmental impact for Chinese economy:1990-2005

    Institute of Scientific and Technical Information of China (English)

    Liu Kailing; Duan Ning; Sun Qihong

    2009-01-01

    The process of economic activities is on the basis of tremendous material inputs.China has been discharging an enormous amount of waste, giving rise to a wide range of environmental impacts.The method of economy-wide material flow analysis (FW-MFA) is one of the effective tools to examine the flow of materials entering physical economies, and recognize early environmental problems.Relevant researches are still at the early stage in China and most focus on material throughput but are rarely concerned about the utilization of recycling resource and environmental impact.Based on more than 3,000 items of data related, materials entering Chinese economy,are classified into three types, and then the characteristics of material input and environmental impact are presented for the years 1990-2005 by using the indicators derived,from EW-MFA.The Ratio of Recycled Material (RRM)is added as the new indicator in order to be in accordance with the need of circular economy being promoted in China.Results show that the great changes in the structure of material input cause the continuous increase of industrial solid waste emissions and the bogging down of material productivity.The RRM reveals that the utilization of recycling resources remains at a fairly low level in China.Finally, some weakness of EW-MFA is discussed according to the calculated results.

  13. Environmental impacts on the evapotranspiration of an water limited and heterogeneous Mediterranean ecosystem.

    Science.gov (United States)

    Montaldo, N.; Curreli, M.; Corona, R.; Oren, R.

    2015-12-01

    Mediterranean water limited ecosystems are characterized by an heterogeneous spatial distribution of different plant functional types (PFT), such as grass and trees, competing for water use. Typically, during the dry summers, these ecosystems are characterized by a simple dual PFTs system with strong-resistant woody vegetation and bare soil, since grass died. The coupled use of sap flow measurements and eddy covariance technique is essential to estimate Evapotransiration (ET) in an heterogeneous ecosystem. An eddy covariance - micrometeorological tower has been installed since 2003 and 33 thermo-dissipation probes based on the Granier technique have installed at the Orroli site in Sardinia (Italy). The site landscape is a mixture of Mediterranean patchy vegetation types: wild olives, different shrubs and herbaceous species, which died during the summer. The sensors have been installed at the Orroli site into 15 wild olives clumps with different characteristics in terms of tree size, exposition to wind and solar radiation and soil depth. A network of 30 soil moisture sensors has also been installed for monitoring soil moisture spatial and temporal dynamics and their correlation with trees. Sap flow measurements show the significantly impacts on ET of soil moisture, radiation, vapor pressure deficit (VPD) and interestingly of tree position into the clump, showing double rates for the trees inside the wild olive clumps. The sap flow sensor outputs are analyzed for estimating innovative allometric relationships between sapwood area, diameter, canopy cover area, which are needed for the correct upscale of the local tree measurements to the site plot larger scale. Finally using an innovative scaling procedure, the sap-flow transpiration at field scale have been compared to the eddy covariance ET, showing the approximation of the eddy covariance technique. Finally the impact of environmental factors on ET for different soil depth and tree position is demonstrated.

  14. Limited impact on decadal-scale climate change from increased use of natural gas.

    Science.gov (United States)

    McJeon, Haewon; Edmonds, Jae; Bauer, Nico; Clarke, Leon; Fisher, Brian; Flannery, Brian P; Hilaire, Jérôme; Krey, Volker; Marangoni, Giacomo; Mi, Raymond; Riahi, Keywan; Rogner, Holger; Tavoni, Massimo

    2014-10-23

    The most important energy development of the past decade has been the wide deployment of hydraulic fracturing technologies that enable the production of previously uneconomic shale gas resources in North America. If these advanced gas production technologies were to be deployed globally, the energy market could see a large influx of economically competitive unconventional gas resources. The climate implications of such abundant natural gas have been hotly debated. Some researchers have observed that abundant natural gas substituting for coal could reduce carbon dioxide (CO2) emissions. Others have reported that the non-CO2 greenhouse gas emissions associated with shale gas production make its lifecycle emissions higher than those of coal. Assessment of the full impact of abundant gas on climate change requires an integrated approach to the global energy-economy-climate systems, but the literature has been limited in either its geographic scope or its coverage of greenhouse gases. Here we show that market-driven increases in global supplies of unconventional natural gas do not discernibly reduce the trajectory of greenhouse gas emissions or climate forcing. Our results, based on simulations from five state-of-the-art integrated assessment models of energy-economy-climate systems independently forced by an abundant gas scenario, project large additional natural gas consumption of up to +170 per cent by 2050. The impact on CO2 emissions, however, is found to be much smaller (from -2 per cent to +11 per cent), and a majority of the models reported a small increase in climate forcing (from -0.3 per cent to +7 per cent) associated with the increased use of abundant gas. Our results show that although market penetration of globally abundant gas may substantially change the future energy system, it is not necessarily an effective substitute for climate change mitigation policy.

  15. Waste-based materials; capability, application and impact on indoor environment – literature review

    DEFF Research Database (Denmark)

    Krejcirikova, Barbora; Rode, Carsten; Kolarik, Jakub;

    2014-01-01

    This paper reviews and discusses various sustainable materials utilizing waste products with the focus on their properties having an impact on the indoor environmental conditions and indoor air quality (IAQ). Materials included in the review are selected considering the following aspects: sustain......: sustainability, cradle to cradle perspective, application, their impact on indoor environment and human well-being. The attempt of the paper is to cover a wide spectrum of information so to provide better understanding of waste utilization in construction industry.......This paper reviews and discusses various sustainable materials utilizing waste products with the focus on their properties having an impact on the indoor environmental conditions and indoor air quality (IAQ). Materials included in the review are selected considering the following aspects...

  16. Exploring the impact of a coordinated variable speed limit control on congestion distribution in freeway

    Directory of Open Access Journals (Sweden)

    Jing Cao

    2015-06-01

    Full Text Available Over the past few decades, urban freeway congestion has been highly recognized as a serious and worsening traffic problem in the world. To relieve freeway congestion, several active traffic and demand management (ATDM methods have been developed. Among them, variable speed limit (VSL aims at regulating freeway mainline flow upstream to meet existing capacity and to harmonize vehicle speed. However, congestion may still be inevitable even with VSL implemented due to extremely high demand in actual practice. This study modified an existing VSL strategy by adding a new local constraint to suggest an achievable speed limit during the control period. As a queue is a product of the congestion phenomenon in freeway, the incentives of a queue build-up in the applied coordinated VSL control situation were analyzed. Considering a congestion occurrence (a queue build-up characterized by a sudden and sharp speed drop, speed contours were utilized to demonstrate the congestion distribution over a whole freeway network in various scenarios. Finally, congestion distributions found in both VSL control and non-VS control situations for various scenarios were investigated to explore the impact of the applied coordinated VSL control on the congestion distribution. An authentic stretch of Whitemud Drive (WMD, an urban freeway corridor in Edmonton, Alberta, Canada, was employed to implement this modified coordinated VSL control strategy; and a calibrated micro-simulation VISSIM model (model functions was applied as the substitute of the real-world traffic system to test the above mentioned performance. The exploration task in this study can lay the groundwork for future research on how to improve the presented VSL control strategy for achieving the congestion mitigation effect on freeway.

  17. Implementation of e-commerce in developing countries: impact and its limitations-Albanian Case study

    Directory of Open Access Journals (Sweden)

    Genti Çela

    2016-07-01

    Full Text Available The implementation of Electronic Commerce (hereinafter referred to as "e-Commerce" in developed countries has been proven as an indisputable potential to ameliorate the efficiency and productivity in different areas, therefore, its implementation is attracting significant attention in developing countries. Despite its opportunities established in developed countries, there were many doubts about the e-commerce implementation in developing countries. That reluctance is heightened by the limited number of studies on e-commerce and the lack of legislation. This paper aims to contribute on filling the research gap by highlighting the e-commerce implementation in Albania as a developing country, its importance, the level of trust, its benefits, its positive or negative impacts and its limitations. This study will be continuously and accordingly updated with new evidence based on research results, along with future developments of Albania’s economic, political, social and demographic environment. This is because different areas represent different infrastructure and different social and economic characteristics, different levels of trust on transactions, different attitudes towards institutions. We have also take into consideration that different communities have different attitudes toward the acceptance and developments of e-Commerce system. In this paper, we present a comprehensive approach to e-commerce, concentrating specifically on Albanian case. Firstly we analyze the current situation of e-Commerce. Secondly we pay attention to the benefits and legal strategies for its implementation. The third step consists in presenting the relevant objectives. We believe and insist that the development of e-commerce in developing nations, - including Albania, has a positive perspective, if the government, companies and the public can better understand and implement e-Commerce.

  18. Impact of temperature and humidity on chemical and sensory emissions from building materials.

    Science.gov (United States)

    Fang, L; Clausen, G; Fanger, P O

    1999-09-01

    The chemical and sensory emissions from five building materials (carpet, polyvinyl chloride (PVC) flooring, sealant, floor varnish and wall paint) were tested under different combinations of temperature and relative humidity in the ranges 18-28 degrees C and 30-70% relative humidity (RH). The experiment was performed in a climate chamber where a specially designed test system was built to study emissions from the five materials. The test system could provide different temperatures and humidities of air around the materials, while the air, after being polluted by the emissions from the materials, could be reconditioned to 23 degrees C and 50% RH for sensory assessments. The experiment was designed to separate the direct impact of temperature and humidity on perception from the impact on sensory emission. The study found little influence of temperature on the emissions from the five materials whether expressed in chemical or sensory terms. The effect of humidity was found to be significant only for the waterborne materials--floor varnish and wall paint. Compared with the direct impact of temperature and humidity on the perception of air quality, the impact of temperature and humidity on sensory emissions from the building materials has a secondary influence on perceived air quality.

  19. Impact and residual fatigue behavior of ARALL and AS6/5245 composite material

    Science.gov (United States)

    Johnson, W. S.

    1989-01-01

    The impact sensitivity of aramide fiber-reinforced aluminum laminates (ARALL) was investigated by testing two types of ARALL (7075 aluminum prestrained and 2024 aluminum not prestrained), via static indentation, and the results were compared to those of sheet aluminum alloys 7075-T6 and 2024-T3 and to a state of the art composite AS6/5245. It was found that the impact resistance of the two ARALL samples was inferior to that of monolithic sheet aluminum samples, although the ARALL material made with 2024-T3 aluminum was superior to that made with 7075-T6 aluminum. The impact damage resistance of ARALL materials was at least equal to that of AS6/5245, and the AS6/5245 had higher residual tension-tension fatigue strength after impact than the ARALL samples. It was also found that the prestraining of the ARALL reduced the fatigue growth of impact damage.

  20. Materials Pushing the Application Limits of Wire Grid Polarizers further into the Deep Ultraviolet Spectral Range

    CERN Document Server

    Siefke, Thomas; Pfeiffer, Kristin; Puffky, Oliver; Dietrich, Kay; Franta, Daniel; Ohlídal, Ivan; Szeghalmi, Adriana; Kley, Ernst-Bernhard; Tünnermann, Andreas

    2016-01-01

    Wire grid polarizers (WGPs), periodic nano-optical meta-surfaces, are convenient polarizing elements for many optical applications. However, they are still inadequate in the deep ultraviolet spectral range. We show that to achieve high performance ultraviolet WGPs a material with large absolute value of the complex permittivity and extinction coefficient at the wavelength of interest has to be utilized. This requirement is compared to refractive index models considering intraband and interband absorption processes. We elucidate why the extinction ratio of metallic WGPs intrinsically humble in the deep ultraviolet, whereas wide bandgap semiconductors are superior material candidates in this spectral range. To demonstrate this, we present the design, fabrication and optical characterization of a titanium dioxide WGP. At a wavelength of 193 nm an unprecedented extinction ratio of 384 and a transmittance of 10 % is achieved.

  1. Forming limit prediction using a self-consistent crystal plasticity framework: a case study for body-centered cubic materials

    Science.gov (United States)

    Jeong, Youngung; Pham, Minh-Son; Iadicola, Mark; Creuziger, Adam; Foecke, Timothy

    2016-06-01

    A rate-dependent self-consistent crystal plasticity model was incorporated with the Marciniak-Kuczyński model in order to study the effects of anisotropy on the forming limits of BCC materials. The computational speed of the model was improved by a factor of 24 when running the simulations for several strain paths in parallel. This speed-up enabled a comprehensive investigation of the forming limits of various BCC textures, such as γ , σ , α , η and ɛ fibers and a uniform (random) texture. These simulations demonstrate that the crystallographic texture has significant (both positive and negative) effects on the resulting forming limit diagrams. For example, the γ fiber texture, which is often sought through thermo-mechanical processing due to a high r-value, had the highest forming limit in the balanced biaxial strain path but the lowest forming limit under the plane strain path among the textures under consideration. A systematic investigation based on the results produced by the current model, referred to as ‘VPSC-FLD’, suggests that the r-value does not serve as a good measure of forming limit strain. However, model predictions show a degree of correlation between the r-value and the forming limit stress.

  2. Breaking the GaN material limits with nanoscale vertical polarisation super junction structures: A simulation analysis

    Science.gov (United States)

    Unni, Vineet; Sankara Narayanan, E. M.

    2017-04-01

    This is the first report on the numerical analysis of the performance of nanoscale vertical superjunction structures based on impurity doping and an innovative approach that utilizes the polarisation properties inherent in III–V nitride semiconductors. Such nanoscale vertical polarisation super junction structures can be realized by employing a combination of epitaxial growth along the non-polar crystallographic axes of Wurtzite GaN and nanolithography-based processing techniques. Detailed numerical simulations clearly highlight the limitations of a doping based approach and the advantages of the proposed solution for breaking the unipolar one-dimensional material limits of GaN by orders of magnitude.

  3. Impact of Wettability on Fracturing of Nano-Granular Materials

    Science.gov (United States)

    Trojer, M.; Juanes, R.

    2014-12-01

    Hydraulic fracturing, or fracking, is a well-known reservoir stimulation technique, by which the permeability of the near-wellbore region is enhanced through the creation of tensile fractures within the rock, formed in the direction perpendicular to the least principal stress. While it is well known that fracturing of granular media strongly depends on the type of media, the pore fluids, and the fracking fluids, the interplay between multiphase flow, wettability and fracture mechanics of shale-like (nano-granular) materials remains poorly understood. Here, we study experimentally the dynamics of multiphase-flow fracking in nano-porous media and its dependence on the wetting properties of the system. The experiments consist in saturating a thin bed of glass beads with a viscous fluid, injecting a less viscous fluid, and imaging the invasion morphology. We investigate three control parameters: the injection rate of the less-viscous invading phase, the confining stress, and the contact angle, which we control by altering the surface chemistry of the beads and the Hele-Shaw cell. We quantify the dynamic fracture pattern by means of particle image velocimetry (PIV), and elucidate the role of wettability on the emerging flow physics at the length scale of the viscous-frictional instability.

  4. Strength degradation and failure limits of dense and porous ceramic membrane materials

    DEFF Research Database (Denmark)

    Pećanac, G.; Foghmoes, Søren Preben Vagn; Lipińska-Chwałek, M.;

    2013-01-01

    Thin dense membrane layers, mechanically supported by porous substrates, are considered as the most efficient designs for oxygen supply units used in Oxy-fuel processes and membrane reactors. Based on the favorable permeation properties and chemical stability, several materials were suggested...... as promising membrane and substrate materials: Ba0.5Sr0.5Co0.8Fe0.2O3−δ, La0.6−xSr0.4Co0.2Fe0.8O3−δ (x=0, 0.02) and Ce0.9Gd0.1O1.95−δ. Although membranes operate at elevated temperatures, the ends of tubes in certain three-end concepts remain almost at room temperature. The current work concentrates...... on the failure potential of these membrane parts, where in a complex device also the highest residual stresses should arise due to differences in thermal expansion. In particular, sensitivity of the materials to subcritical crack growth was assessed since the long-term reliability of the component does not only...

  5. Evaluating dynamic building materials: The potential impact of climatically responsive building enclosures

    Science.gov (United States)

    Kienzl, Nico H.

    Despite the great interest and investment in new material technologies and advanced simulation tools, predictions for the potential impact of dynamic envelope systems so far have been based on simulations of the overall building. However, overall building simulations provide limited insights into the behavior of the building envelope since results of these types of simulations are affected by many factors that are independent of or indirectly influenced by the building envelope. Therefore, it is difficult to isolate the impact of the building envelope on building energy consumption independent of building-specific factors such as building geometry, construction, environmental systems, and building use. In order to understand and quantify the dynamic nature of environmentally responsive envelope systems, designers and engineers necessitate a new method that enables the direct evaluation of only the envelope. This method needs to be able to predict the heat transfer through dynamic building envelopes under variable environmental conditions. Ultimately, this new method should help identify the applicability of new technologies early in the design process when detailed information on a building's design or operation are not yet available. This thesis establishes a new method and a validated reference case for the evaluation of climatically responsive building envelopes with dynamic material properties. The method isolates the performance of the building envelope in a building energy simulation model through transformation of a validated BESTEST model. It allows for parametric evaluation of the thermal performance of dynamic building envelopes under a wide range of environmental boundary conditions in comparison to existing reference technologies. This method can serve as a starting point for the critical evaluation of the impact that dynamic envelope systems have on the heat balance of buildings. The method was applied to the evaluation of electrochromic glazing to

  6. Potentialities and limitations of direct alcoholic fermentation of starchy material with amylolytic yeasts

    Energy Technology Data Exchange (ETDEWEB)

    Mot, R. de; Dijck, K. van; Donkers, A.; Verachtert, H.

    1985-07-01

    The fermentation characteristics of a large number of starch-degrading yeasts were compared. None of the amylolytic yeasts currently recognized, appear to be entirely suitable for direct alcoholic fermentation of starchy biomass. The species capable of extensive starch hydrolysis produce only low amounts of ethanol from glucose and dextrin, one of the major limitations being their low ethanol tolerances. Some of the less-active yeasts have much better glucose-fermentation characteristics, but dextrin conversion is limited probably due to the nature of their enzyme systems. Using an ..cap alpha..-amylase dextrin (22.5% w/v), ethanol yields of about 70% were obtained with Saccharomyces diastaticus strains. Through associative fermentation of S. diastaticus and other selected amylolytic yeasts slightly better yields, however not exceeding 80%, were obtained.

  7. One hundred years of limited impact of Jaspers' General Psychopathology on US psychiatry.

    Science.gov (United States)

    de Leon, Jose

    2014-02-01

    Jaspers, a German psychiatrist, published General Psychopathology in 1913. Jaspers, Schneider, and Mayer-Gross were members of the Heidelberg school. General Psychopathology, indirectly through Schneider's and Mayer-Gross' textbooks and directly by its English translation in 1963, led to a narrow set of schizophrenia criteria in the United Kingdom. General Psychopathology had very limited direct impact on US psychiatry, which adopted a broader schizophrenia definition. The difference between UK and US schizophrenia was a key element in the Diagnostic and Statistical Manual of Mental Disorders, Third Edition, and the neo-Kraepelinian revolution. General Psychopathology contains two essential interrelated ideas: a) psychiatry is a hybrid scientific discipline that must combine natural and social science methods that provide an explanation of illness that follows the medical model and an understanding of psychiatric abnormalities that are variations of human living, respectively, and b) psychiatric disorders are heterogeneous. Berrios' ideas on the hybridity of psychiatry in the United Kingdom and McHugh's ideas on psychiatric diagnoses in the United States can be considered neo-Jasperian approaches because they further elaborate these two Jasperian concepts in the late 20th century.

  8. Knockouts of high-ranking males have limited impact on baboon social networks.

    Science.gov (United States)

    Franz, Mathias; Altmann, Jeanne; Alberts, Susan C

    Social network structures can crucially impact complex social processes such as collective behaviour or the transmission of information and diseases. However, currently it is poorly understood how social networks change over time. Previous studies on primates suggest that `knockouts' (due to death or dispersal) of high-ranking individuals might be important drivers for structural changes in animal social networks. Here we test this hypothesis using long-term data on a natural population of baboons, examining the effects of 29 natural knockouts of alpha or beta males on adult female social networks. We investigated whether and how knockouts affected (1) changes in grooming and association rates among adult females, and (2) changes in mean degree and global clustering coefficient in these networks. The only significant effect that we found was a decrease in mean degree in grooming networks in the first month after knockouts, but this decrease was rather small, and grooming networks rebounded to baseline levels by the second month after knockouts. Taken together our results indicate that the removal of high-ranking males has only limited or no lasting effects on social networks of adult female baboons. This finding calls into question the hypothesis that the removal of high-ranking individuals has a destabilizing effect on social network structures in social animals.

  9. Mechanical response of a fibre reinforced earthen material under static and impact loadings

    Science.gov (United States)

    Aymerich, Francesco; Fenu, Luigi; Francesconi, Luca; Meloni, Paola

    2015-09-01

    This study examines the improvements provided by the insertion of hemp fibres with different weight fractions and lengths in an earthen material. The structural response of the materials was investigated by means of static and impact bending tests carried out on notched samples. The main focus of the analyses was in the characterization of the structural properties of the materials in terms of fracture resistance, post-cracking performance and energy absorption capability. The results of the study show that hemp fibres improve significantly the mechanical and fracture properties of the earthen material under both static and dynamic bending. It was also found that the structural properties of unreinforced and reinforced earthen materials are highly sensitive to the stress-rate, with higher strength and fracture resistance under impact loading than under static loading.

  10. Response of Organic Materials to Hypervelocity Impacts (up to 11.2 km/sec)

    Science.gov (United States)

    Bass, D. S.; Murphy, W. M.; Miller, G. P.; Grosch, D. J.; Walker, J. D.; Mullin, A.; Waite, J. H.

    1998-09-01

    It is speculated that organic-rich planetesimals played a role in the origin of life on Earth. However, the mechanism by which organics could have been delivered from space to a planetary surface is difficult to determine. Particularly problematic is the question of the stability of organic material under hypervelocity impact conditions. Although some evidence suggests organic molecules cannot survive impacts from projectile velocities greater than about 10 km/sec [1], other investigators have found that impacts create a favorable environment for post-shock recombination of organic molecules in the plume phase [2, 3]. Understanding the mechanisms involved in delivering organics to a planetary surface remains difficult to assess due to the lack of experimental results of hypervelocity impacts, particularly in the velocity range of tens of km/sec. Organic material preservation and destruction from impact shocks, the synthesis of organics in the post-impact plume environment, and implications of these processes for Earth and Mars can be investigated by launching an inorganic projectile into an analog planetesimal-and-bolide organic-rich target. We explored the pressure and temperature ranges of hypervelocity impacts (11.2 km/sec) through simulations with CTH impact physics computer code. Using an inhibited shaped-charge launcher, we also experimentally determined the response of organic material to hypervelocity impacts. Initial work focused on saturating well-characterized zeolitic tuff with an aqueous solution containing dissolved naphthalene, a common polycyclic aromatic hydrocarbon (PAH). Porosity measurements, thin section, and x-ray diffraction analyses were performed to determine that the tuff is primarily fine-grained clinoptilolite. In order to distinguish between contaminants and compounds generated or destroyed in the impact, we tagged the aqueous component of our target with deuterium. Experimental tests revealed that to first order, naphthalene survived

  11. Social construction and materiality: the limits of indeterminacy in therapeutic settings.

    Science.gov (United States)

    Lannamann, J W

    1998-01-01

    By drawing parallels between the courtroom testimony of a Christian Science practitioner and an intersession conversation between systemic family therapists, I critique the abstract idealism of language-centered social constructionism. I argue that social constructionist inquiry that highlights the indeterminacy of meaning without a corresponding emphasis on the responsive embodied practices of family members glosses over the material conditions shaping the politics of interaction. The implications of this problem are discussed as they relate to the setting of family therapy, where social construction theory is often used to guide practical interventions.

  12. Replica-exchange Wang Landau sampling: pushing the limits of Monte Carlo simulations in materials sciences

    Energy Technology Data Exchange (ETDEWEB)

    Perera, Meewanage Dilina N [ORNL; Li, Ying Wai [ORNL; Eisenbach, Markus [ORNL; Vogel, Thomas [Los Alamos National Laboratory (LANL); Landau, David P [University of Georgia, Athens

    2015-01-01

    We describe the study of thermodynamics of materials using replica-exchange Wang Landau (REWL) sampling, a generic framework for massively parallel implementations of the Wang Landau Monte Carlo method. To evaluate the performance and scalability of the method, we investigate the magnetic phase transition in body-centered cubic (bcc) iron using the classical Heisenberg model parameterized with first principles calculations. We demonstrate that our framework leads to a significant speedup without compromising the accuracy and precision and facilitates the study of much larger systems than is possible with its serial counterpart.

  13. Critical Minerals and Energy–Impacts and Limitations of Moving to Unconventional Resources

    Directory of Open Access Journals (Sweden)

    Benjamin C. McLellan

    2016-05-01

    Full Text Available The nexus of minerals and energy becomes ever more important as the economic growth and development of countries in the global South accelerates and the needs of new energy technologies expand, while at the same time various important minerals are declining in grade and available reserves from conventional mining. Unconventional resources in the form of deep ocean deposits and urban ores are being widely examined, although exploitation is still limited. This paper examines some of the implications of the transition towards cleaner energy futures in parallel with the shifts through conventional ore decline and the uptake of unconventional mineral resources. Three energy scenarios, each with three levels of uptake of renewable energy, are assessed for the potential of critical minerals to restrict growth under 12 alternative mineral supply patterns. Under steady material intensities per unit of capacity, the study indicates that selenium, indium and tellurium could be barriers in the expansion of thin-film photovoltaics, while neodymium and dysprosium may delay the propagation of wind power. For fuel cells, no restrictions are observed.

  14. Beam Interaction with Thin Materials: Heat Deposition, Cooling Phenomena and Damage Limits

    CERN Document Server

    Sapinski, M

    2012-01-01

    Thin targets, inserted into particle beams can serve various purposes, starting from beam emittance measurements like in wire scanner or scintillating screens up to beam content modifications like in case of stripper foils. The mechanisms of energy deposition in a thin target for various beam types are discussed, together with properties of particles produced in this kind of interaction. The cooldown processes, from heat transfer up to cooling by sublimation, and their efficiencies are presented. Finally, damage conditions are discussed and conclusions about typical damage limits are drawn. The experiments performed with the wire scanners at CERN accelerators and a mathematical model of heating and cooling of a wire are presented.

  15. The use of reactive material for limiting P-leaching from green roof substrate.

    Science.gov (United States)

    Bus, Agnieszka; Karczmarczyk, Agnieszka; Baryła, Anna

    2016-01-01

    The aim of the study is to assess the influence of drainage layer made of reactive material Polonite(®) on the water retention and P-PO(4) concentration in runoff. A column experiment was performed for extensive substrate underlined by 2 cm of Polonite(®) layer (SP) and the same substrate without supporting layer as a reference (S). The leakage phosphorus concentration ranged from 0.001 to 0.082 mg P-PO(4)·L(-1), with average value 0.025 P-PO(4)·L(-1) of S experiment and 0.000-0.004 P-PO(4)·L(-1) and 0.001 P-PO(4)·L(-1) of SP experiment, respectively. The 2 cm layer of Polonite(®) was efficient in reducing P outflow from green roof substrate by 96%. The average effluent volumes from S and SP experiments amounted 61.1 mL (5.8-543.3 mL) and 46.4 mL (3.3-473.3 mL) with the average irrigation rate of 175.5 mL (6.3-758.0 mL). The substrate retention ability of S and SP experiments was 65% and 74%, respectively. Provided with reactive materials, green roof layers implemented in urban areas for rain water retention and delaying runoff also work for protection of water quality.

  16. Limit analysis and conic programming: `porous Drucker Prager' material and Gurson's model

    Science.gov (United States)

    Trillat, Malorie; Pastor, Joseph; Thoré, Philippe

    2006-10-01

    Extending a previous work on the Gurson model for a 'porous von Mises' material, the present study first focuses on the yield criterion of a 'porous Drucker-Prager' material with spherical cavities. On the basis of the Gurson micro-macro model and a second order conic programming ( SOCP) formulation, calculated inner and outer approaches to the criterion are very close, providing a reliable estimate of the yield criterion. Comparison with an analytical criterion recently proposed by Barthélémy and Dormieux—from a nonlinear homogenization method—shows both excellent agreement when considering tensile average boundary conditions and substantial improvement under compressive conditions. Then the results of an analogous study in the case of cylindrical cavities in plane strain are presented. It is worth noting that obtaining these results was made possible by using MOSEK, a recent commercial SOCP code, whose impressive efficiency was already seen in our previous works. To cite this article: M. Trillat et al., C. R. Mecanique 334 (2006).

  17. RCRA materials analysis by laser-induced breakdown spectroscopy: Detection limits in soils

    Energy Technology Data Exchange (ETDEWEB)

    Koskelo, A.; Cremers, D.A.

    1994-09-01

    The goal of the Technical Task Plan (TTP) that this report supports is research, development, testing and evaluation of a portable analyzer for RCRA and other metals. The instrumentation to be built will be used for field-screening of soils. Data quality is expected to be suitable for this purpose. The data presented in this report were acquired to demonstrate the detection limits for laser-induced breakdown spectroscopy (LIBS) of soils using instrument parameters suitable for fieldable instrumentation. The data are not expected to be the best achievable with the high pulse energies available in laboratory lasers. The report presents work to date on the detection limits for several elements in soils using LIBS. The elements targeted in the Technical Task Plan are antimony, arsenic, beryllium, cadmium, chromium, lead, selenium, and zirconium. Data for these elements are presented in this report. Also included are other data of interest to potential customers for the portable LIBS apparatus. These data are for barium, mercury, cesium and strontium. Data for uranium and thorium will be acquired during the tasks geared toward mixed waste characterization.

  18. Long Standing Esophageal Perforation due to Foreign Body Impaction in Children: A Therapeutic Challenge in a Resource Limited Setting

    Directory of Open Access Journals (Sweden)

    Ngo Nonga Bernadette

    2017-01-01

    Full Text Available Late presentation of foreign body impaction in the esophagus, complicated by perforation in children, has rarely been reported in the literature. Esophageal surgery is very difficult and challenging in Cameroon (a resource limited setting. We are reporting herein 2 cases of esophageal perforation in children seen very late (12 days and 40 days after foreign body impaction, complicated with severe sepsis, who were successfully operated upon with very good results.

  19. Railgun Application for High Energy Impact Testing of Nano-Reinforced Kevlar-Based Composite Materials

    Science.gov (United States)

    Micheli, D.; Vricella, A.; Pastore, R.; Morles, R. B.; Marchetti, M.

    2013-08-01

    An advanced electromagnetic accelerator, called railgun, has been assembled and tuned in order to perform high energy impact test on layered structures. Different types of layered composite materials have been manufactured and characterized in terms of energy absorbing capability upon impact of metallic bullets fired at high velocity. The composite materials under testing are manufactured by integrating several layers of Kevlar fabric and carbon fiber ply within a polymeric matrix reinforced by carbon nanotubes at 1% of weight percentage. The experimental results show that the railgun-device is a good candidate to perform impact testing of materials in the space debris energy range, and that carbon nanotubes may enhance, when suitably coupled to the composite's matrix, the excellent antiballistic properties of the Kevlar fabrics.

  20. Simulating The Impact Of The Material Flow In The Jordanian Construction Supply Chain And Its Impact On Project Performance

    Directory of Open Access Journals (Sweden)

    Dr. Ghaith Al-Werikat

    2015-08-01

    Full Text Available With the new developments and challenges within the construction industry improving the construction supply chain is becoming a major concern to both governments and industries. Improving the construction supply chain helps in improving the quality of construction projects reducing cost wastes delays and other disruptions. This paper discusses the analysis of material flow in the construction supply chain. The methodology consisted of preliminary investigations survey and simulation development to analyse the extent of impact that material flow has on construction projects in Jordan. Both the main survey and the investigations revealed that material flow delays are caused mainly by 3 types of delays late delivery wrong specification and material damaged on site. The highest impact regarding late deliveries was scaffolding with a 16 probability of occurrence a 2-day delay on the activitys duration. Concrete ranked highest regarding wrong specification with a 19 probability of occurrence an 8-day delay the activitys duration. Regarding materials damaged on site bricks ranked highest with a 9 probability of occurrence a 3-day delay on the duration. The simulation results exhibited a delay of 50 on the projects duration and a probability of a delay occurring is 9.2.

  1. Near Field Heat Transfer between Random Composite Materials: Applications and Limitations

    Science.gov (United States)

    Santiago, Eva Yazmin; Esquivel-Sirvent, Raul

    2017-02-01

    We present a theoretical study of the limits and bounds of using effective medium approximations in the calculation of the near field radiative heat transfer between a composite system made of Au nanoparticles in a SiC host and an homogeneous SiC slab. The effective dielectric function of the composite slab is calculated using three different approximations: Maxwell-Garnett, Bruggeman, and Looyenga's. In addition, we considered an empirical fit to the effective dielectric function by Grundquist and Hunderi. We show that the calculated value of the heat flux in the near field is dependent on the model, and the difference in the effective dielectric function is larger around the plasmonic response of the Au nanoparticles. This, in turn, accounts for the difference in the near field radiative heat flux. For all values of filling fractions, the Looyenga approximation gives a lower bound for the heat flux.

  2. Near field heat transfer between random composite materials. Applications and limitations

    Energy Technology Data Exchange (ETDEWEB)

    Santiago, Eva Yazmin; Esquivel-Sirvent, Raul [Univ. Nacional Autonoma de Mexico (Mexico). Inst. de Fisica

    2017-05-01

    We present a theoretical study of the limits and bounds of using effective medium approximations in the calculation of the near field radiative heat transfer between a composite system made of Au nanoparticles in a SiC host and an homogeneous SiC slab. The effective dielectric function of the composite slab is calculated using three different approximations: Maxwell-Garnett, Bruggeman, and Looyenga's. In addition, we considered an empirical fit to the effective dielectric function by Grundquist and Hunderi. We show that the calculated value of the heat flux in the near field is dependent on the model, and the difference in the effective dielectric function is larger around the plasmonic response of the Au nanoparticles. This, in turn, accounts for the difference in the near field radiative heat flux. For all values of filling fractions, the Looyenga approximation gives a lower bound for the heat flux.

  3. Scaling limits for shortest path lengths along the edges of stationary tessellations - Supplementary material

    CERN Document Server

    Voss, Florian; Schmidt, Volker

    2009-01-01

    We consider spatial stochastic models, which can be applied e.g. to telecommunication networks with two hierarchy levels. In particular, we consider two Cox processes concentrated on the edge set of a random tessellation, where the points can describe the locations of low-level and high-level network components, respectively, and the edge set the underlying infrastructure of the network, like road systems, railways, etc. Furthermore, each low-level component is marked with the shortest path along the edge set to the nearest high-level component. We investigate the typical shortest path length of the resulting marked point process, which is an important characteristic e.g. in performance analysis and planning of telecommunication networks. In particular, we show that its distribution converges to simple parametric limit distributions if a certain scaling factor converges to zero and infinity, respectively. This can be used to approximate the density of the typical shortest path length by analytical formulae.

  4. Impact-induced tensile waves in a kind of phase-transforming materials

    CERN Document Server

    Huang, Shou-Jun

    2010-01-01

    This paper concerns the global propagation of impact-induced tensile waves in a kind of phase-transforming materials. It is well-known that the governing system of partial differential equations is hyperbolic-elliptic and the initial-boundary value problem is not well-posed at all levels of loading. By making use of fully nonlinear stress-strain curve to model this material, Dai and Kong succeeded in constructing a physical solution of the above initial-boundary value problem. For the impact of intermediate range, they assumed that $\\beta<3\\alpha$ in the stress-response function for simplicity. In this paper, we revisit the impact problem and consider the propagation of impact-induced tensile waves for all values of the parameters $\\alpha$ and $\\beta$. The physical solutions for all levels of loading are obtained completely.

  5. Limited impact of intratumour heterogeneity on molecular risk assignment in endometrial cancer.

    Science.gov (United States)

    van Esterik, Manouk; Van Gool, Inge C; de Kroon, Cor D; Nout, Remi A; Creutzberg, Carien L; Smit, Vincent T H B M; Bosse, Tjalling; Stelloo, Ellen

    2017-04-11

    Individual prediction of tumour behaviour based on molecular markers may refine adjuvant treatment strategies in endometrial cancer (EC). As these molecular alterations are determined in a small tumour fraction, high intratumour heterogeneity may interfere with correct risk prediction. This study aimed to investigate to which extent intratumour heterogeneity exists for molecular markers and whether it affects the molecular risk assignment in EC. Forty-nine ECs (three tumour blocks/case) were selected with alterations in POLE (n=10), CTNNB1 (n=8), p53 (n=10), mismatch repair (n=11), L1CAM (n=10), and ECs without any of these markers (n=9). Nine ECs carried more than one molecular marker. All 147 blocks were analysed for POLE exonuclease domain and CTNNB1 exon 3 mutations, and for p53, mismatch repair and L1CAM protein expression. All blocks were assigned to a favourable, intermediate or unfavourable risk group, based on a molecular risk assignment. Concordance between the three tumour blocks for POLE and CTNNB1 mutational status, and p53, mismatch repair and L1CAM protein expression was found in 100% (48/48), 95.9% (47/49), 93.9% (46/49), 98.0% (48/49), and 91.8% (45/49) of tumours, respectively. These discordances were found in a total of nine cases (18.4%). The intratumour heterogeneity impacted the risk assignment in five cases (10.2%). Intratumour heterogeneity of prognostic molecular markers in EC without morphologic heterogeneity is uncommon among three tumour fractions, affecting the molecular risk allocation in a limited number of cases. This low intratumour heterogeneity facilitates the implementation of the molecular risk assignment, advocating its use in clinical decision making.

  6. Validation of the material point method and plasticity with Taylor impact tests

    CERN Document Server

    Banerjee, Biswajit

    2012-01-01

    Taylor impacts tests were originally devised to determine the dynamic yield strength of materials at moderate strain rates. More recently, such tests have been used extensively to validate numerical codes for the simulation of plastic deformation. In this work, we use the material point method to simulate a number of Taylor impact tests to compare different Johnson-Cook, Mechanical Threshold Stress, and Steinberg-Guinan-Cochran plasticity models and the vob Mises and Gurson-Tvergaard-Needleman yield conditions. In addition to room temperature Taylor tests, high temperature tests have been performed and compared with experimental data.

  7. THE ENVIRONMENTAL IMPACT OF THE DELIVERY OF MINERAL RAW MATERIALS USED FOR BUILDING MATERIALS PRODUCTION TO THE CITY OF ZAGREB AND THE ZAGREB COUNTY

    Directory of Open Access Journals (Sweden)

    Karolina Novak

    2011-12-01

    Full Text Available Mineral raw material transport directly affects a product’s unit price and exhaust gases amounts. Transportation length is proportional to raw material price; its low price enables short transportation distances only. Taking into account stone aggregates delivered to Zagreb, the consequence of exploitation fields closure in the Zagreb area, particularly within the Medvednica Nature Park, we tried to answer the question of the impact of transport distances on the greenhouse gas emissions. Certain models will present environmental impact of the stone aggregate transportation and of nearby city quarries. The generally accepted public opinion on the closure of nearby city quarries as the best solution to environmental pollution will have to be reviewed. Mining works are predestined by mineral resources sites and limited by real possibilities and intentions of the community, therefore the experts, i.e. miners, geologists and other geoscientists, should be actively involved in spatial planning. During the years of intensive construction, millions of tons have been delivered from distances up to 100 km. The question arises whether some more rational solutions could be generated by more appropriate spatial planning? (the paper is published in Croatian

  8. The potential, limitations, and challenges of divide and conquer quantum electronic structure calculations on energetic materials.

    Energy Technology Data Exchange (ETDEWEB)

    Tucker, Jon R.; Magyar, Rudolph J.

    2012-02-01

    High explosives are an important class of energetic materials used in many weapons applications. Even with modern computers, the simulation of the dynamic chemical reactions and energy release is exceedingly challenging. While the scale of the detonation process may be macroscopic, the dynamic bond breaking responsible for the explosive release of energy is fundamentally quantum mechanical. Thus, any method that does not adequately describe bonding is destined to lack predictive capability on some level. Performing quantum mechanics calculations on systems with more than dozens of atoms is a gargantuan task, and severe approximation schemes must be employed in practical calculations. We have developed and tested a divide and conquer (DnC) scheme to obtain total energies, forces, and harmonic frequencies within semi-empirical quantum mechanics. The method is intended as an approximate but faster solution to the full problem and is possible due to the sparsity of the density matrix in many applications. The resulting total energy calculation scales linearly as the number of subsystems, and the method provides a path-forward to quantum mechanical simulations of millions of atoms.

  9. Measurement of Nucleate Pool Boiling Heat Transfer Limit using Fuel Cladding Material

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chi Young; Shin, Chang Hwan; Oh, Dong Seok; Chun, Tae Hyun; In, Wang Kee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    Zircaloy has been widely used as a fuel cladding material of light water reactor for more than three decades because it has a lower neutron absorption cross section and cracking rate. Recently, HANA-6 has been developed in KAERI (Korea Atomic Energy Research Institute) as the advanced fuel cladding for high burn-up fuel. Generally, under the normal and accident operating conditions of a nuclear reactor, the nuclear fuel cladding of zirconium based alloys undergoes the surface change, and the oxide layer can be formed. In such a case, the previous CHF correlations should be assessed and examined using the experimental results for not a fresh zircaloy surface but an oxidized one, to predict and examine the thermal margin and safety of a nuclear reactor core. Therefore, the experimental data using the oxidized zircaloy surface need to be provided quantitatively. In this paper, the CHF in saturated water pool boiling is measured and discussed using the specimens of zircaloy-4, HANA-6, and oxidized zircaloy-4 in high temperature air environment. The CHF of zircaloy-4, HANA-6, and oxidized surface was tested. Zircaloy-4 and HANA-6 had a similar CHF performance. This is because both are the zirconium based alloys, and appear the almost same water contact angle. On the other hands, the oxidized specimen became to be higher CHF than plain zircaloy-4 and HANA-6 specimens, due to smaller water contact angle (i. e., good hydrophilicity of specimen). The Kandlikar's (2001) correlation reasonably predicted the present experimental data.

  10. High-impact strength acrylic denture base material processed by autoclave.

    Science.gov (United States)

    Abdulwahhab, Salwan Sami

    2013-10-01

    To investigate the effect of two different cycles of autoclave processing on the transverse strength, impact strength, surface hardness and the porosity of high-impact strength acrylic denture base material. High Impact Acryl was the heat-cured acrylic denture base material included in the study. A total of 120 specimens were prepared, the specimens were grouped into: control groups in which high-impact strength acrylic resins processed by conventional water-bath processing technique (74°C for 1.5 h then boil for 30 min) and experimental groups in which high-impact strength acrylic resins processed by autoclave at 121°C, 210 kPa .The experimental groups were divided into (fast) groups for 15 min, and (slow) groups for 30 min. To study the effect of the autoclave processing (Tuttnauer 2540EA), four tests were conducted transverse strength (Instron universal testing machine), impact strength (Charpy tester), surface hardness (shore D), and porosity test. The results were analyzed to ANOVA and LSD test. In ANOVA test, there were highly significant differences between the results of the processing techniques in transverse, impact, hardness, and porosity test. The LSD test showed a significant difference between control and fast groups in transverse and hardness tests and a non-significant difference in impact test and a highly significant difference in porosity test; while, there were a highly significant differences between control and slow groups in all examined tests; finally, there were a non-significant difference between fast and slow groups in transverse and porosity tests and a highly significant difference in impact and hardness tests. In the autoclave processing technique, the slow (long) curing cycle improved the tested physical and mechanical properties as compared with the fast (short) curing cycle. The autoclave processing technique improved the tested physical and mechanical properties of High Impact Acryl. Copyright © 2013 Japan Prosthodontic Society

  11. [Study on limit detection of flavones in diterpene ginkgolides meglumine injection materials by LC-MS and HPLC-DAD].

    Science.gov (United States)

    Bi, Sen; Li, Yan-jing; Huang, Wen-zhe; Kang, Dan-yu; Ding, Gang; Xiao, Wei

    2015-08-01

    Limit test of flavones in diterpene ginkgolides meglumine injection materials by UV-Vis and HPLC-DAD method was studied in this essay. The HPLC-DAD method has lower LOD (about 1% of the UV-Vis), that is, the sensitivity is higher than UV-Vis method. Through the analysis of the kinds of flavonoids ingredients in the samples by LC-MS, the three compounds with highest contents are kaempferol, quercetin and isorhamnetin. Kaempferol, quercetin and isorhamnetin were chosen as reference compounds for HPLC analysis, and the HPLC separation analysis was carried on an Agilent Eclipse plus C18 column (4.6 mm x 250 mm, 5 μm) with methanol and water containing 0.4% phosphoric acid (50: 50) as mobile phase, and the flow rate was 1.0 mL x min(-1). The detection wavelength was set at 360 nm. This method has good specificity, precision and reproducibility. The LODs of quercetin, kaempferide and isorhamnetin were 27.6, 22.3, 29.5 μg x L(-1). The average recovery was 87.9% (RSD 3.3%), 91.7% (RSD 3.1%), 88.3 (RSD 1.3%) for quercetin, kaempferide and isorhamnetin, respectively. Based on the 10 batches of sample results and sensitivity of different HPLC, the content of total flavonoids ingredients of diterpene ginkgolides meglumine injection materials was limited no more than 2 x 10(-5). This method is simple, quick and has good maneuverability, and could be used to the limit test of flavonoids in the diterpene ginkgolides meglumine injection materials.

  12. [Limiting a Medline/PubMed query to the "best" articles using the JCR relative impact factor].

    Science.gov (United States)

    Avillach, P; Kerdelhué, G; Devos, P; Maisonneuve, H; Darmoni, S J

    2014-12-01

    Medline/PubMed is the most frequently used medical bibliographic research database. The aim of this study was to propose a new generic method to limit any Medline/PubMed query based on the relative impact factor and the A & B categories of the SIGAPS score. The entire PubMed corpus was used for the feasibility study, then ten frequent diseases in terms of PubMed indexing and the citations of four Nobel prize winners. The relative impact factor (RIF) was calculated by medical specialty defined in Journal Citation Reports. The two queries, which included all the journals in category A (or A OR B), were added to any Medline/PubMed query as a central point of the feasibility study. Limitation using the SIGAPS category A was larger than the when using the Core Clinical Journals (CCJ): 15.65% of PubMed corpus vs 8.64% for CCJ. The response time of this limit applied to the entire PubMed corpus was less than two seconds. For five diseases out of ten, limiting the citations with the RIF was more effective than with the CCJ. For the four Nobel prize winners, limiting the citations with the RIF was more effective than the CCJ. The feasibility study to apply a new filter based on the relative impact factor on any Medline/PubMed query was positive. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  13. Finite Element Simulation of the Vibration Provided by Sandwich Rigid Panel with a Resilient Material In Between under Heavyweight Impact

    Directory of Open Access Journals (Sweden)

    Shun-Fa Hwang

    2014-01-01

    Full Text Available The purpose of the present work is to use an explicit finite element code to model the impact behavior of a heavyweight impact source like rubber ball and to predict the floor impact vibration of resilient materials, which are used in the floor coverings construction for sound insulation. To simulate the impact force of rubber balls, the hyperviscoelastic rubber model is applied. Then, this rubber model is used in the simulation for the impact vibration of resilient materials. The results indicate that the hyperviscoelastic rubber model could precisely simulate the impact force of rubber balls, as its two parameters are properly chosen according to the desired impact force. Also, the present model could capture the impact and vibration behavior of the considered materials and reasonably evaluate the insulation effect of resilient materials.

  14. Measuring the impact of health problems among adults with limited mobility in Thailand: further validation of the Perceived Impact of Problem Profile

    Directory of Open Access Journals (Sweden)

    Manderson Lenore

    2008-01-01

    Full Text Available Abstract Background The Perceived Impact of Problem Profile (PIPP was developed to provide a tool for measuring the impact of a health condition from the individual's perspective, using the ICF model as a framework. One of the aims of the ICF is to enable the comparison of data across countries, however, relatively little is known about the subjective experience of disability in middle and low-income countries. The aim of this study was to assess the validity of the Perceived Impact of Problem Profile (PIPP for use among adults with a disability in Thailand using Rasch analysis. Methods A total of 210 adults with mobility impairment from the urban, rural and remote areas of northeast Thailand completed the PIPP, which contains 23 items assessing both impact and distress across five key domains (Self-care, Mobility, Participation, Relationships, and Psychological Well-being. Rasch analysis, using RUMM2020, was conducted to assess the internal validity and psychometric properties of the PIPP Impact subscales. Validation of the PIPP Impact scales was conducted by comparing scores across the different response levels of the EQ5D items. Results Rasch analysis indicated that participants did not clearly differentiate between 'impact' and 'distress,' the two aspects assessed by the PIPP. Further analyses were therefore limited to the PIPP Impact subscales. These showed adequate psychometric properties, demonstrating fit to the Rasch model and good person separation reliability. Preliminary validity testing using the EQ5D items provided support for the PIPP Impact subscales. Conclusion The results provide further support for the psychometric properties of the PIPP Impact scales and indicate that it is a suitable tool for use among adults with a locomotor disability in Thailand. Further research is needed to validate the PIPP across different cultural contexts and health conditions and to assess the usefulness of separate Impact and Distress subscales.

  15. Hypervelocity Impacts on ISS Handrails and Evaluation of Alternative Materials to Prevent Extravehicular Mobility Unit (EMU) Glove Damage During EVA

    Science.gov (United States)

    Ryan, Shannon; Christiansen, Eruc; Davis, B. Alan; Ordonez, Erick

    2009-01-01

    During post-flight processing of STS-116, damage to crewmember Robert Curbeam's Phase VI Glove Thermal Micrometeoroid Garment was discovered. This damage consisted of: loss of RTV-157 palm pads on the thumb area on the right glove, a 0.75 inch cut in the Vectran adjacent to the seam and thumb pad (single event cut), constituting the worst glove damage ever recorded for the U.S. space program. The underlying bladder and restraint were found not be damaged by this event. Evaluation of glove damage found that the outer Vectran fibers were sliced as a result of contact with a sharp edge or pinch point rather than general wear or abrasion (commonly observed on the RTV pads). Damage to gloves was also noted on STS-118 and STS-120. One potential source of EMU glove damages are sharp crater lips on external handrails, generated by micrometeoroid and orbital debris (MMOD) impacts. In this paper, the results of a hypervelocity impact (HVI) test program on representative and actual ISS handrails are presented. These tests were performed in order to characterize impact damage profiles on ISS handrails and evaluate alternatives for limiting risk to future missions. It was determined that both penetrating and non-penetrating MMOD impacts on aluminum and steel ISS handrails are capable of generating protruding crater profiles which exceed the heights required for EMU glove abrasion risk by an order of magnitude. Testing demonstrated that flexible overwraps attached to the outside of existing handrails are capable of limiting contact between hazardous crater formations and crewmember gloves during extravehicular activity (EVA). Additionally, replacing metallic handrails with high strength, low ductility, fiber reinforced composite materials would limit the formation of protruding crater lips on new ISS modules.

  16. Impacts of Vehicle Weight Reduction via Material Substitution on Life-Cycle Greenhouse Gas Emissions

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Jarod C.; Sullivan, John L.; Burnham, Andrew; Elgowainy, Amgad

    2015-10-20

    This study examines the vehicle-cycle impacts associated with substituting lightweight materials for those currently found in light-duty passenger vehicles. We determine part-based energy use and greenhouse gas (GHG) emission ratios by collecting material substitution data from both the literature and automotive experts and evaluating that alongside known mass-based energy use and GHG emission ratios associated with material pair substitutions. Several vehicle parts, along with full vehicle systems, are examined for lightweighting via material substitution to observe the associated impact on GHG emissions. Results are contextualized by additionally examining fuel-cycle GHG reductions associated with mass reductions relative to the baseline vehicle during the use phase and also determining material pair breakeven driving distances for GHG emissions. The findings show that, while material substitution is useful in reducing vehicle weight, it often increases vehicle-cycle GHGs depending upon the material substitution pair. However, for a vehicle’s total life cycle, fuel economy benefits are greater than the increased burdens associated with the vehicle manufacturing cycle, resulting in a net total life-cycle GHG benefit. The vehicle cycle will become increasingly important in total vehicle life-cycle GHGs, since fuel-cycle GHGs will be gradually reduced as automakers ramp up vehicle efficiency to meet fuel economy standards.

  17. Waste management issues and their potential impact on technical specifications of CANDU fuel materials

    Energy Technology Data Exchange (ETDEWEB)

    Tait, J.C.; Johnson, L.H. [Atomic Energy of Canada Limited, Pinawa, Manitoba (Canada)

    1997-07-01

    The technical specifications for the composition of nuclear fuels and materials used in Canada's CANDU reactors have been developed by AECL and materials manufacturers, taking into account considerations specific to their manufacture and the effect of minor impurities on fuel behaviour in reactor. Nitrogen and chlorine are examples of UO{sub 2} impurities, however, where there is no technical specification limit. These impurities are present in the source materials or introduced in the fabrication process and are neutron activated to {sup 14}C and {sup 36}C1, which after {sup 129}I , are the two most significant contributors to dose in safety assessments for the disposal of used fuel. For certain impurities, environmental factors, particularly the safety of the disposal of used fuels, should be taken into consideration when deriving 'allowable' impurity limits for nuclear fuel materials. (author)

  18. Impact of Electronic Teaching Materials on Process of Education--Results of an Experiment

    Science.gov (United States)

    Záhorec, Ján; Hašková, Alena; Munk, Michal

    2010-01-01

    In their paper the authors deal with the vital issues of creation and application of electronic teaching materials for natural science subjects teaching. They describe an experimental examination of qualitative impact of these aids on education. The authors present a part of research results, which they obtained in a major research focused on…

  19. The environmental impact and recovery at two dumping sites for dredged material in the North Sea

    NARCIS (Netherlands)

    Stronkhorst, J.; Ariese, F.; Hattum, van B.; Postma, J.F.; Kluijver, de M.; Besten, den P.; Bergman, M.J.N.; Daan, R.; Murk, A.J.; Vethaak, A.D.

    2003-01-01

    The environmental impact and recovery associated with the long and uninterrupted disposal of large volumes of moderately contaminated dredged material from the port of Rotterdam was studied at nearby dumping sites in the North Sea. Observations were made on sediment contamination, ecotoxicity, bioma

  20. Interlibrary Loan Requests for Locally Available Materials: WorldCat Local's Impact

    Science.gov (United States)

    Gaffney, Megan

    2012-01-01

    Several studies have researched the reasons and patterns for academic library users' interlibrary loan requests for materials already available at their college or university library. This study examines interlibrary loan statistics at the University of Delaware for four academic years to determine whether WorldCat Local impacts requests for…

  1. Impacts of Insufficient Instructional Materials on Teaching Biology: Higher Education Systems in Focus

    Science.gov (United States)

    Edessa, Sutuma

    2017-01-01

    The purpose of this study was to assess and determine impacts of insufficient instructional materials and ineffective lesson delivery methods on teaching in biology higher education. The participants of this study were 60 trainees who graduated in Bachelor of Sciences from eight public universities in majoring biology. Data for the study was…

  2. The Psychosexual Impacts on Adolescent Girls Viewing Sexually Explicit Internet Material

    Science.gov (United States)

    Grant, Piper S.

    2014-01-01

    Literature indicates that 72% of adolescent girls are exposed to sexually explicit Internet material (SEIM) before the age of 18, and between 2%-30% of girls report intentionally seeking SEIM. Despite the recognition that adolescent girls are consuming SEIM, and that their use impacts behaviors, beliefs, and attitudes, there has been limited…

  3. ENVIRONMENTAL IMPACT ANALYSIS OF HEAVY METAL CONCENTRATIONS IN WASTE MATERIALS USED IN ROAD CONSTRUCTION

    Directory of Open Access Journals (Sweden)

    Ivanka Netinger Grubeša

    2016-12-01

    Full Text Available Use of solid waste in place of conventional materials in civil engineering structures preserves natural resources and energy and avoids expensive and/or potentially harmful waste disposal. Many studies are investigating the application of waste materials in civil engineering structures. However, in an effort to find out new areas of waste materials utilization, the environmental impact of the installation of such materials in building structures often remains neglected. This study focused on the environmental aspect of the application of currently investigated waste materials in Croatia with an emphasis on heavy metal content. Heavy metal concentration in steel slag, river sediment, and biomass ash was measured, and the possibility of their use in road construction in accordance with currently valid legislation was assessed.

  4. Wind farms generation limits and its impact in real-time voltage stability assessment

    DEFF Research Database (Denmark)

    Perez, Angel; Jóhannsson, Hjörtur; Østergaard, Jacob

    2015-01-01

    indicates the distance to the limit activation and theeffect of each load in such a limit. The wind farm control schemesincludes voltage control and it is represented as a constantcurrent at its limit. A criteria to select the critical bus bar, basedon the generator transformation coefficients, is presented....... Thismethodology is tested in a platform that produces synthesizedPMU measurements from time-domain simulations and criticalboundary for the wind-farm limits are shown. The methodology isalso tested for synchronous machines and its parallel structure isexploited when implemented in a High Performance...

  5. Bryophytes as Climate Indicators: moss and liverwort photosynthetic limitations and carbon isotope signals in organic material and peat deposits

    Science.gov (United States)

    Griffiths, H.; Royles, J.; Horwath, A.; Hodell, D. A.; Convey, P.; Hodgson, D.; Wingate, L.; Ogeé, J.

    2011-12-01

    Bryophytes make a significant contribution to carbon sequestration and storage in polar, boreal, temperate and tropical biomes, and yet there is limited understanding of the determinants of carbon isotope composition. Bryophytes are poikilohydric and lack stomata in the vegetative (gametophyte) stage, and lack of roots and reliance on liquid water to maintain hydration status also imposes diffusional limitations on CO2 uptake and extent of carbon isotope discrimination. Real-time gas exchange and instantaneous discrimination studies can be used to quantify responses to liquid phase limitation. Thus, wetted tissues show less negative δ13C signals due to liquid phase conductance and, as the thallus surface dries, maximum CO2 assimilation and discrimination are attained when the limitation is primarily the internal (mesophyll) conductance. Continued desiccation then leads to additional biochemical limitation in drought tolerant species, and low discrimination, although the carbon gain is low at this time. In this paper we explore the extent of carbon isotope discrimination in bulk organic material and cellulose as a function of climatic and environmental conditions, in temperate, tropical and Antarctic bryophytes. Field studies have been used to investigate seasonal variations in precipitation and water vapour inputs for cloud forest formations as a function of bryophyte biomass, diversity and isotope composition in epiphytes (particularly leafy liverworts) along an altitudinal gradient in Peru. In the Antarctic, moss banks sampled on Signy Island consisted of only two species, primarily Chorisodontium aciphyllum and some Polytrichum strictum, allowing the collection of shallow and deep cores representative of growth over the past 200 to 2000 years. The well-preserved peat has provided data on growth (14C) and stable isotopic proxies (13C, 18O) for material contemporary with recent anthropogenic climate forcing (over the past 200 years), for comparison with longer

  6. The "Strength" of Cometary Surface Material: Relevance of Deep Impact Results for Future Comet Missions

    Science.gov (United States)

    Biele, J.; Ulamec, S.; Richter, L.; Kührt, E.; Knollenberg, J.; Möhlmann, D.

    In the view of the ongoing Rosetta Mission which was launched in March 2004 and will arrive at the target comet 67P Churyumov-Gerasimenko in 2014 where a Lander is going to be delivered the results of the Deep Impact Mission in particular regarding comet surface properties have been acknowledged with highest interest Analysis of the velocity of dust ejecta indicates very soft surface material of comet Tempel 1 with strength of only 65 Pa A Hearn M F et al Deep Impact Excavating Comet Tempel 1 Science 310 258-264 14 Oct 2005 It appears however necessary to discuss three principal issues in the interpretation of the data 1 By the impact shock itself the material is stressed fractured and its tensile strength is modified Thus the pristine material properties can most likely not be determined with the applied method 2 Due to the impact a non-negligible amount of gas has been released from an extended source modifying the velocity distribution of the ejected dust particles Thus the detection of a minimum velocity of dust grains cannot be directly related to the material strength 3 The definition of strength in A Hearn et al 2005 needs to be defined more clearly in order to draw conclusions on e g the penetration of a lander device with an impact speed of 1 m s Slow penetration into cometary material is depending primarily on the compressive strength which is typically at least one order of magnitude higher than the tensile strength We will discuss the three issues stated above and estimate the real compressive

  7. Assessing the Impact of Computer Programming in Understanding Limits and Derivatives in a Secondary Mathematics Classroom

    Science.gov (United States)

    de Castro, Christopher H.

    2011-01-01

    This study explored the development of student's conceptual understandings of limit and derivative when utilizing specifically designed computational tools. Fourteen students from a secondary Advanced Placement Calculus AB course learned and explored the limit and derivative concepts from differential calculus using visualization tools in the…

  8. Assessing the Impact of Computer Programming in Understanding Limits and Derivatives in a Secondary Mathematics Classroom

    Science.gov (United States)

    de Castro, Christopher H.

    2011-01-01

    This study explored the development of student's conceptual understandings of limit and derivative when utilizing specifically designed computational tools. Fourteen students from a secondary Advanced Placement Calculus AB course learned and explored the limit and derivative concepts from differential calculus using visualization tools in the…

  9. Impacts of Daily Bag Limit Reductions on Angler Effort in Wisconsin Walleye Lakes

    Science.gov (United States)

    Beard, T.D.; Cox, S.P.; Carpenter, S.R.

    2003-01-01

    Angler effort is an important factor affecting recreational fisheries. However, angler responses are rarely incorporated into recreational fisheries regulations or predictions. Few have attempted to examine how daily bag limit regulations affect total angling pressure and subsequent stock densities. Our paper develops a theoretical basis for predicting angler effort and harvest rate based on stock densities and bag limit regulations. We examined data from a management system that controls the total exploitation of walleyes Sander vitreus (formerly Stizostedion vitreum) in northern Wisconsin lakes and compared these empirical results with the predictions from a theoretical effort and harvest rate response model. The data indicated that higher general angler effort occurs on lakes regulated with a 5-walleye daily limit than on lakes regulated with either a 2- or 3-walleye daily limit. General walleye catch rates were lower on lakes with a 5-walleye limit than on lakes with either a 2- or 3-walleye daily limit. An effort response model predicted a logarithmic relationship between angler effort and adult walleye density and that an index of attractiveness would be greater on lakes with high bag limits. Predictions from the harvest rate model with constant walleye catchability indicated that harvest rates increased nonlinearly with increasing density. When the effort model was fitted to data from northern Wisconsin, we found higher lake attractiveness at 5-walleye-limit lakes. We conclude that different groups of anglers respond differently to bag limit changes and that reliance on daily bag limits may not be sufficient to maintain high walleye densities in some lakes in this region.

  10. Impact of pore characteristics of silica materials on loading capacity and release behavior of ibuprofen

    Energy Technology Data Exchange (ETDEWEB)

    Numpilai, Thanapha [Department of Chemical Engineering, Faculty of Engineering, Kasetsart University, Bangkok 10900 (Thailand); Muenmee, Suthaporn [Department of Chemical Engineering, Faculty of Engineering, Kasetsart University, Bangkok 10900 (Thailand); Center for Advanced Studies in Nanotechnology and Its Applications in Chemical Food and Agricultural Industries, Kasetsart University, Bangkok 10900 (Thailand); Witoon, Thongthai, E-mail: fengttwi@ku.ac.th [Department of Chemical Engineering, Faculty of Engineering, Kasetsart University, Bangkok 10900 (Thailand); Center for Advanced Studies in Nanotechnology and Its Applications in Chemical Food and Agricultural Industries, Kasetsart University, Bangkok 10900 (Thailand); NANOTEC-KU-Center of Excellence on Nanoscale Materials Design for Green Nanotechnology, Kasetsart University, Bangkok 10900 (Thailand)

    2016-02-01

    Impact of pore characteristics of porous silica supports on loading capacity and release behavior of ibuprofen was investigated. The porous silica materials and ibuprofen-loaded porous silica materials were thoroughly characterized by N{sub 2}-sorption, thermal gravimetric and derivative weight analyses (TG-DTW), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), transmission electron microscope (TEM) to determine the physical properties of materials, amount of ibuprofen adsorbed and position of ibuprofen. The detailed characterization reveals that the ibuprofen molecules adsorbed inside the mesopores. Increasing the mesopore size from 5 nm to 10 nm increased the ibuprofen loading from 0.74 to 0.85 mmol/g, respectively. Incorporation of macropore into the structure of porous silica materials enhanced the ibuprofen loading capacity of 11.8–20.3%. The ibuprofen-loaded bimodal meso-macroporous silica materials exhibited the highest dissolution of 92 wt.% within an hour. The ibuprofen particles deposited on the external surface of the porous silica materials showed a lower dissolution rate than the ibuprofen adsorbed inside the mesopores due to the formation of ibuprofen crystalline. - Highlights: • Impacts of pore characteristics of supports on adsorption and release of ibuprofen • Increasing mesopore size increased the ibuprofen loading and dissolution rate. • Macropores reduced the diffusion pathway of ibuprofen and dissolution medium.

  11. Impact of atmospheric clutter on Doppler-limited gas sensors in the submillimeter/terahertz.

    Science.gov (United States)

    Medvedev, Ivan R; Neese, Christopher F; Plummer, Grant M; De Lucia, Frank C

    2011-06-20

    It is well known that clutter (spectral interference) from atmospheric constituents can be a severe limit for spectroscopic point sensors, especially where high sensitivity and specificity are required. In this paper, we will show for submillimeter/terahertz (SMM/THz) sensors that use cw electronic techniques the clutter limit for the detection of common target gases with absolute specificity (probability of false alarm ≪ 10⁻¹⁰) is in the ppt (1 part in 10¹²) range or lower. This is because the most abundant atmospheric gases are either transparent to SMM/THz radiation (e.g., CO₂) or have spectra that are very sparse relative to the 10⁵ Doppler-limited resolution elements available (e.g., H₂O). Moreover, the low clutter limit demonstrated for cw electronic systems in the SMM/THz is independent of system size and complexity.

  12. The impact of powder diffraction on the structural characterization of organic crystalline materials.

    Science.gov (United States)

    Tremayne, Maryjane

    2004-12-15

    The bulk properties of organic crystalline materials depend on their molecular and crystal structures but, as many of these materials cannot be prepared in a suitable form for conventional single-crystal diffraction studies, structural characterization and rationalization of these properties must be obtained from powder diffraction data. The recent development of direct-space structure solution methods has enabled the study of a wide range of organic materials using powder diffraction data, many of structural complexity only made tractable by these advances in methodology. These direct-space methods are based on a number of global optimization techniques including Monte Carlo, simulated annealing, genetic algorithm and differential evolution approaches. In this article, the implementation and relative efficiency and reliability of these methods are discussed, and their impact on the structural study of organic materials is illustrated by examples of polymorphic systems, pharmaceutical, pigment and polypeptide structures and compounds used in the study of intermolecular networks.

  13. The impact of mass transfer limitations on size distributions of particle associated SVOCs in outdoor and indoor environments

    DEFF Research Database (Denmark)

    Liu, Cong; Zhang, Yinping; Weschler, Charles J.

    2014-01-01

    ) previously proposed that the rate of mass transfer can impact polycyclic aromatic hydrocarbon (PAH) partitioning among different sized particles, especially for time scales relevant to urban aerosols. The present study quantitatively builds on this idea, presenting a model that incorporates dynamic SVOC....../particle interaction and applying this model to typical outdoor and indoor scenarios. The model indicates that the impact of mass transfer limitations on the size distribution of a particle-associated SVOC can be evaluated by the ratio of the time to achieve gas-particle equilibrium relative to the residence time...... of particles. The higher this ratio, the greater the influence of mass transfer limitations on the size distribution of particle-associated SVOCs. The influence of such constraints is largest on the fraction of particle-associated SVOCs in the coarse mode (>2μm). Predictions from the model have been found...

  14. Advantages and limitations of the Five Domains model for assessing welfare impacts associated with vertebrate pest control.

    Science.gov (United States)

    Beausoleil, N J; Mellor, D J

    2015-01-01

    Many pest control activities have the potential to impact negatively on the welfare of animals, and animal welfare is an important consideration in the development, implementation and evaluation of ethically defensible vertebrate pest control. Thus, reliable and accurate methods for assessing welfare impacts are required. The Five Domains model provides a systematic method for identifying potential or actual welfare impacts associated with an event or situation in four physical or functional domains (nutrition, environment, health or functional status, behaviour) and one mental domain (overall mental or affective state). Here we evaluate the advantages and limitations of the Five Domains model for this purpose and illustrate them using specific examples from a recent assessment of the welfare impacts of poisons used to lethally control possums in New Zealand. The model has a number of advantages which include the following: the systematic identification of a wide range of impacts associated with a variety of control tools; the production of relative rankings of tools in terms of their welfare impacts; the easy incorporation of new information into assessments; and the highlighting of additional information needed. For example, a recent analysis of sodium fluoroacetate (1080) poisoning in possums revealed the need for more information on the period from the onset of clinical signs to the point at which consciousness is lost, as well as on the level of consciousness during or after the occurrence of muscle spasms and seizures. The model is also valuable because it clearly separates physical or functional and affective impacts, encourages more comprehensive consideration of negative affective experiences than has occurred in the past, and allows development and evaluation of targeted mitigation strategies. Caution must be used in interpreting and applying the outputs of the model, most importantly because relative rankings or grades are fundamentally qualitative in

  15. Phylloplane bacteria increase the negative impact of food limitation on insect fitness

    NARCIS (Netherlands)

    Olson, Grant L.; Myers, Judith H.; Hemerik, Lia; Cory, Jenny S.

    2017-01-01

    1. When populations of herbivorous insects increase in density, they can alter the quantity or quality of their food. The impacts of diet-related stressors on insect fitness have been investigated singly, but not simultaneously. 2. Foliage quantity and quality of red alder, Alnus rubra, were

  16. Differential climate impacts for policy-relevant limits to global warming

    NARCIS (Netherlands)

    Schleussner, Carl Friedrich; Lissner, Tabea K.; Fischer, Erich M.; Wohland, Jan; Perrette, Mahé; Golly, Antonius; Rogelj, Joeri; Childers, Katelin; Schewe, Jacob; Frieler, Katja; Mengel, Matthias; Hare, William; Schaeffer, Michiel

    2016-01-01

    Robust appraisals of climate impacts at different levels of global-mean temperature increase are vital to guide assessments of dangerous anthropogenic interference with the climate system. The 2015 Paris Agreement includes a two-headed temperature goal: "holding the increase in the global average

  17. Environmental impact assessment of CCS chains – Lessons learned and limitations from LCA literature

    NARCIS (Netherlands)

    Corsten, M.A.M.; Ramirez, C.A.; Shen, L.; Koornneef, A.; Faaij, A.P.C.

    2013-01-01

    This study performs an assessment of existing LCA literature to obtain insights into potential environmental impacts over the complete life cycle of fossil fuel fired power plants with CCS. CCS results in a net reduction of the GWP of power plants through their life cycle in the order of 65–84% (PC-

  18. Differential climate impacts for policy-relevant limits to global warming

    NARCIS (Netherlands)

    Schleussner, Carl Friedrich; Lissner, Tabea K.; Fischer, Erich M.; Wohland, Jan; Perrette, Mahé; Golly, Antonius; Rogelj, Joeri; Childers, Katelin; Schewe, Jacob; Frieler, Katja; Mengel, Matthias; Hare, William; Schaeffer, Michiel

    2016-01-01

    Robust appraisals of climate impacts at different levels of global-mean temperature increase are vital to guide assessments of dangerous anthropogenic interference with the climate system. The 2015 Paris Agreement includes a two-headed temperature goal: "holding the increase in the global average

  19. Economic and Environmental Impacts of Improving Growth Rate and Feed Efficiency in Fish Farming Depend on Nitrogen and Density Limitation

    OpenAIRE

    Besson, M.; Komen, H.; Vandeputte, M.; Aubin, J.; Boer, De; van Arendonk,

    2014-01-01

    The aim of fish breeding is to increase profit by producing faster growing fish with lower feed intake. However, little is known about the economic and environmental impacts of selective breeding programs for fish. We modelled a fish farm producing African catfish in a Recirculating Aquaculture System (RAS) to calculate economic values of growth rate and feed efficiency with production limited by fish density in rearing tanks and fish nitrogen emission. We also calculated “environmental value...

  20. Research Update: The materials genome initiative: Data sharing and the impact of collaborative ab initio databases

    Science.gov (United States)

    Jain, Anubhav; Persson, Kristin A.; Ceder, Gerbrand

    2016-05-01

    Materials innovations enable new technological capabilities and drive major societal advancements but have historically required long and costly development cycles. The Materials Genome Initiative (MGI) aims to greatly reduce this time and cost. In this paper, we focus on data reuse in the MGI and, in particular, discuss the impact of three different computational databases based on density functional theory methods to the research community. We also discuss and provide recommendations on technical aspects of data reuse, outline remaining fundamental challenges, and present an outlook on the future of MGI's vision of data sharing.

  1. Further development and evaluation of high impact strength denture base materials.

    Science.gov (United States)

    Rodford, R A

    1990-06-01

    The further development of poly(methylmethacrylate) reinforced with low molecular weight polybutadiene-based rubbers previously studied is described. The materials produced have been optimized with respect to impact strength and Young's modulus, giving results up to 0.13 J for the former whilst maintaining the latter at about 2.3 G.Pa. Additionally, the systems have been evaluated with respect to viscoelastic properties, water absorption and the effect of the latter on mechanical properties. Further work on the underlying mechanisms should lead to a greater understanding of these systems which could, in turn, produce more superior materials.

  2. Characterization of Environmental Impact of Building Materials for the Purpose of Ecodesign

    Science.gov (United States)

    Skele, Agnese; Repele, Mara; Bazbauers, Gatis

    2011-01-01

    -The building material manufacturing sector is one of the sectors with the highest consumption of fossil fuel resources. The "cradle-to-gate" study of the ceramic bricks made in the Āne plant of JSC Lode, Latvia, is performed according to ISO standards 14044:2006. Life cycle inventory data have been collected at the factory site. Three different perspectives of the "Eco-Indicator'99" method are used to conduct an environmental characterization of the building materials to obtain the total impact indicator.

  3. Impacts of Vehicle Weight Reduction via Material Substitution on Life-Cycle Greenhouse Gas Emissions.

    Science.gov (United States)

    Kelly, Jarod C; Sullivan, John L; Burnham, Andrew; Elgowainy, Amgad

    2015-10-20

    This study examines the vehicle-cycle and vehicle total life-cycle impacts of substituting lightweight materials into vehicles. We determine part-based greenhouse gas (GHG) emission ratios by collecting material substitution data and evaluating that alongside known mass-based GHG ratios (using and updating Argonne National Laboratory's GREET model) associated with material pair substitutions. Several vehicle parts are lightweighted via material substitution, using substitution ratios from a U.S. Department of Energy report, to determine GHG emissions. We then examine fuel-cycle GHG reductions from lightweighting. The fuel reduction value methodology is applied using FRV estimates of 0.15-0.25, and 0.25-0.5 L/(100km·100 kg), with and without powertrain adjustments, respectively. GHG breakeven values are derived for both driving distance and material substitution ratio. While material substitution can reduce vehicle weight, it often increases vehicle-cycle GHGs. It is likely that replacing steel (the dominant vehicle material) with wrought aluminum, carbon fiber reinforced plastic (CRFP), or magnesium will increase vehicle-cycle GHGs. However, lifetime fuel economy benefits often outweigh the vehicle-cycle, resulting in a net total life-cycle GHG benefit. This is the case for steel replaced by wrought aluminum in all assumed cases, and for CFRP and magnesium except for high substitution ratio and low FRV.

  4. Impact on Generator Reactive Power Limits on a Static Voltage Stability

    Directory of Open Access Journals (Sweden)

    TOVAR-GONZALEZ, E. A.

    2011-11-01

    Full Text Available Voltage stability margin in a power system is closely related with the availability of reactive power in the system. Therefore, adequate modeling of the reactive power sources becomes an important issue in this type of studies. The Minimum Singular Value of the load flow Jacobian matrix has been commonly used as a static voltage stability index. In this paper, such index is used to assess the influence on the static voltage stability limit of modeling the generators reactive power limits by its capability curve. Simulation results on a test system indicate that modeling the reactive power limits of the generating units by the simplified Qmin/Qmax approach, commonly used by most of the load flow programs, yields optimistic values for this voltage stability index.

  5. Impact of Load Behavior on Transient Stability and Power Transfer Limitations

    DEFF Research Database (Denmark)

    Gordon, Mark

    2009-01-01

    This paper presents utility based load modeling practices and explores the interaction between loads and the power system and the effect of the interaction on transient stability and power transfer limitations. The effect of load composition is investigated at major load centers together with the......This paper presents utility based load modeling practices and explores the interaction between loads and the power system and the effect of the interaction on transient stability and power transfer limitations. The effect of load composition is investigated at major load centers together...

  6. Updating the Northern Tsetse Limit in Burkina Faso (1949–2009: Impact of Global Change

    Directory of Open Access Journals (Sweden)

    Fabrice Courtin

    2010-04-01

    Full Text Available The northern distribution limit of tsetse flies was updated in Burkina Faso and compared to previous limits to revise the existing map of these vectors of African trypanosomiases dating from several decades ago. From 1949 to 2009, a 25- to 150-km shift has appeared toward the south. Tsetse are now discontinuously distributed in Burkina Faso with a western and an eastern tsetse belt. This range shift can be explained by a combination of decreased rainfall and increased human density. Within a context of international control, this study provides a better understanding of the factors influencing the distribution of tsetse flies.

  7. High Velocity Impact Interaction of Metal Particles with Porous Heterogeneous Materials with an Inorganic Matrix

    Science.gov (United States)

    Glazunov, A. A.; Ishchenko, A. N.; Afanasyeva, S. A.; Belov, N. N.; Burkin, V. V.; Rogaev, K. S.; Tabachenko, A. N.; Khabibulin, M. V.; Yugov, N. T.

    2016-03-01

    A computational-experimental investigation of stress-strain state and fracture of a porous heterogeneous material with an inorganic matrix, used as a thermal barrier coating of flying vehicles, under conditions of a high-velocity impact by a spherical steel projectile imitating a meteorite particle is discussed. Ballistic tests are performed at the velocities about 2.5 km/s. Numerical modeling of the high-velocity impact is described within the framework of a porous elastoplastic model including fracture and different phase states of the materials. The calculations are performed using the Euler and Lagrange numerical techniques for the velocities up to 10 km/s in a complete-space problem statement.

  8. Results of regulatory impact survey of industrial and medical materials licensees of the Office of Nuclear Material Safety and Safeguards

    Energy Technology Data Exchange (ETDEWEB)

    Lach, D.; Melber, B.; Brichoux, J. [Battelle Human Affairs Research Center, Seattle, WA (United States); Hattrup, M.; Conger, R.; Hughes, K. [Pacific Northwest Lab., Richland, WA (United States)

    1995-06-01

    This report presents the findings of a regulatory impact survey of nuclear materials licensees of the United States Nuclear Regulatory Commission (NRC). Commissioners of the NRC directed staff to provide the Commission with first hand information from licensees that could be used to improve the overall regulatory program. A self-administered, mail-out survey questionnaire was used to collect data from a sample of licensees who had interaction with the NRC during the previous 12 months. A total of 371 respondents of the 589 who were sent questionnaires returned completed surveys, for a response rate of 63%. The body of the report presents the findings of the survey including a brief introduction to the approach used, followed by survey findings regarding regulations, policies and regulatory guidance; experience with licensing applications, renewals and amendments; inspections; reporting requirements; and enforcement actions. The appendices of the report include a copy of the survey as administered to licensees, a fuller description of the survey design and data collection methods, and detailed graphic material describing survey responses.

  9. Development of A Tabulated Thermo-Viscoplastic Material Model with Regularized Failure for Dynamic Ductile Failure Prediction of Structures under Impact Loading

    Science.gov (United States)

    Buyuk, Murat

    It is important to understand the dynamic failure behavior of structures subjected to impact loading in order to improve the survivability. Materials under impact are utterly affected by large deformations, high strain-rates, temperature softening and varying stress-states, which finally may lead to failure. It is shown that the impact characteristics are prone to change with several independent factors such as; impact speed, material thickness, and shape and orientation of the impacting object. Validated numerical simulations of impact tests reveal that the failure on ductile metals occur at certain locations of the failure locus that is constructed on a space as a function of all three stress invariants, which indicates that the failure depends profoundly on the state-of-stress. It is shown that existing material models are not always successful enough to cover the whole range of the failure locus and predict the failure. Therefore, it is a common practice to use different sets of material model parameters tuned or calibrated to cover a specific region of the failure loci in an ad hoc manner for practical reasons to match particular test results. Even in that case, specially tuned material properties are not capable of predicting these limited cases if differences in the mesh size and pattern need to be considered. In this dissertation a new, generic, thermo-elastic/viscoplastic material model with regularized failure is introduced. The new material model is implemented into a non-linear, explicit dynamics finite element code, LS-DYNA. A von Mises type isotropic, isochoric plasticity is utilized, where isotropic hardening, strain-rate hardening and temperature softening is considered. The model takes adiabatic heating and softening into account due to the plastic work. The constitutive relation is coupled with a new regularized accumulated failure law that is specifically developed to cover a large extent of the failure locus as a function of state

  10. IMPACT TESTING OF MATERIALS USING AN EIGHT-INCH AIR GUN AND COMPUTER REDUCTION OF DATA

    Energy Technology Data Exchange (ETDEWEB)

    Thorne, L. F.

    1973-10-01

    A mechanical shock actuator has been converted into an air gun capable of firing 8-inch-·diameter (20.32 cm) projectiles to velocities exceeding 1000 fps (304.8 m/ s). This new capability has been used to study the effect of impact velocity upon the energy.absorbed by crushable materials. Shockpulse data is reduced by computer techniques and test results are displayed in either tabular or graphic format by use of the C DC 6600 Calcomp plotter.

  11. Impact of Bilingual Education Programs on Limited English Proficient Students and Their Peers

    DEFF Research Database (Denmark)

    Daysal, N. Meltem; Chin, Aimee; Imberman, Scott

    2013-01-01

    Texas requires a school district to offer bilingual education when its enrollment of limited English proficient (LEP) students in a particular elementary grade and language is twenty or higher. Using school panel data, we find a significant increase in the probability that a district provides...

  12. The Impact of the Graphical Approach on Students' Understanding of the Formal Definition of Limit

    Science.gov (United States)

    Quesada, Antonio; Einsporn, Richard L.; Wiggins, Muserref

    2008-01-01

    The purpose of this study was to determine if the use of a graphical teaching and learning approach via the graphing calculator enhances students' understanding of the formal definition of limit. College students in six sections of Calculus I participated by completing a test prior to the introduction of the definition, and completing a second…

  13. Elevated CO2 and Phosphate Limitation Favor Micromonas pusilla through Stimulated Growth and Reduced Viral Impact

    NARCIS (Netherlands)

    Maat, Douwe S.; Crawfurd, Katherine J.; Timmermans, Klaas R.; Brussaard, Corina P. D.

    2014-01-01

    Growth and viral infection of the marine picoeukaryote Micromonas pusilla was studied under a future-ocean scenario of elevated partial CO2 (pCO(2); 750 mu atm versus the present-day 370 mu atm) and simultaneous limitation of phosphorus (P). Independent of the pCO(2) level, the ratios of M. pusilla

  14. Potential Impact of Latest Proposals for New European Vehicle Noise Limits

    NARCIS (Netherlands)

    Dittrich, M.G.; Roo, F. de

    2013-01-01

    Noise emission of new road vehicles is regulated by European Directives [1] and subsequent amendments. Proposals for tighter noise emission limits for road vehicles made by the European Commission in 2011 [2] have been adopted in modified form by the European Parliament in 2013 [3]. In the VENOLIVA

  15. Exceedance of critical loads and of critical limits impacts tree nutrition across Europe

    DEFF Research Database (Denmark)

    Waldner, P.; Thimonier, A.; Graf Pannatier, E.

    2015-01-01

    Key message Exceedance of critical limits in soil solution samples was more frequent in intensively monitored forest plots across Europe with critical loads for acidity and eutrophication exceeded compared to other plots from the same network. Elevated inorganic nitrogen concentrations in soil so...

  16. The Impact of Debt Limitations and Referenda Requirements on the Cost of School District Bond Issues

    Science.gov (United States)

    Harris, Mary H.; Munley, Vincent G.

    2011-01-01

    One distinction between the markets for corporate and municipal bonds involves institutional constraints that apply to some municipal bond issues. This research focuses on how public finance institutions, in particular explicit debt limits and referenda requirements, affect the borrowing cost of individual school district bond issues. The…

  17. Nonsmooth modal analysis from elementary impact oscillators to turbomachines: limitations and avenues

    OpenAIRE

    Thorin, Anders; Legrand, Mathias

    2016-01-01

    International audience; In mechanical engineering, nonlinear modes characterise the behaviour of nonlinear vibratory systems. In the current state-of-the-art, they are well defined for smooth nonlinear systems (of moderate size) of Ordinary Differential Equations governing the dynamics. They are defined as continua of periodic orbits forming two-dimensional invariant manifolds in the state space. This framework has lately been extended to nonsmooth mechanical systems involving impact dynamics...

  18. The Impact of Arms Limitation Agreements and Export Control Regulations of International Commercial Launch Activities

    Science.gov (United States)

    Freeland, Steven

    2002-01-01

    The commercial launch industry is by its very nature a global sector dominated by multinationals that operate across national boundaries. Since the end of the Cold War, new launch operators have become increasingly reliant on existing space and propulsion technology from Russia and other former constituent republics of the Soviet Union. With this in mind, the impact of export controls imposed by various countries under various internationally agreements, especially those of Australia, Russia and the United States, has become an increasingly important factor in the day-to-day operation of commercial launch operators. This is particularly true for launch operators utilising converted ballistic missiles as launch vehicles, as they have to consider also the impact of arms reduction treaties, such as START, on their launch operations. This paper explores the legal and administrative operations of the START and export control regimes operated by Russia and the United States, as well as emerging launching States such as Australia, and how they impact on the logistical operations of domestic or multinational commercial launch operators.

  19. 10 CFR Appendix A to Subpart A of... - Format for Presentation of Material in Environmental Impact Statements

    Science.gov (United States)

    2010-01-01

    ... A of Part 51—Format for Presentation of Material in Environmental Impact Statements 1. General 2.... Appendices 1. General. (a) The Commission will use a format for environmental impact statements which will... following standard format for environmental impact statements should be followed unless there is a...

  20. Analysis of the ballistic impact response of a composite material using FAST Infrared Imagery

    Science.gov (United States)

    Marcotte, Frederick; Ouellet, Simon; Farley, Vincent

    2013-05-01

    The level of protection offered by a given ballistic material is typically evaluated in terms of a set of projectiles and their associated velocity at which a certain percentage of the projectiles are expected to perforate. (i.e. FSP 17gr : V50 = 500m/s, 9mm FMJ; V0=500m/s). These metrics give little information about the physical phenomena by which energy is dispersed, spread or absorbed in a specific target material. Aside from post-test inspection of the impacted material, additional information on the target response is traditionally obtained during a test from the use of high speed imaging, whether it is from a single camera aimed at the impact surface or the backface, or from a set of camera allowing full 3-D reconstruction of a deformed surface. Again, this kind of data may be difficult to interpret if the interest is in the way energy is managed in the target in real time. Recent technological progress in scientific grade high-speed infrared (IR) camera demonstrated that these phenomena can straightforwardly be measured using IR thermal imaging. This paper presents promising results obtained from Telops FAST-IR 1500 infrared camera on an aramid-based ballistic composite during an impact from a small caliber fragment simulating projectile (FSP).

  1. Hypervelocity impact testing of advanced materials and structures for micrometeoroid and orbital debris shielding

    Science.gov (United States)

    Ryan, Shannon; Christiansen, Eric L.

    2013-02-01

    A series of 66 hypervelocity impact experiments have been performed to assess the potential of various materials (aluminium, titanium, copper, stainless steel, nickel, nickel/chromium, reticulated vitreous carbon, silver, ceramic, aramid, ceramic glass, and carbon fibre) and structures (monolithic plates, open-cell foam, flexible fabrics, rigid meshes) for micrometeoroid and orbital debris (MMOD) shielding. Arranged in various single-, double-, and triple-bumper configurations, screening tests were performed with 0.3175 cm diameter Al2017-T4 spherical projectiles at nominally 6.8 km/s and normal incidence. The top performing shields were identified through target damage assessments and their respective weight. The top performing candidate shield at the screening test condition was found to be a double-bumper configuration with a 0.25 mm thick Al3003 outer bumper, 6.35 mm thick 40 PPI aluminium foam inner bumper, and 1.016 mm thick Al2024-T3 rear wall (equal spacing between bumpers and rear wall). In general, double-bumper candidates with aluminium plate outer bumpers and foam inner bumpers were consistently found to be amongst the top performers. For this impact condition, potential weight savings of at least 47% over conventional all-aluminium Whipple shields are possible by utilizing the investigated materials and structures. The results of this study identify materials and structures of interest for further, more in-depth, impact investigations.

  2. A computational study of influence of helmet padding materials on the human brain under ballistic impacts.

    Science.gov (United States)

    Salimi Jazi, Mehdi; Rezaei, Asghar; Karami, Ghodrat; Azarmi, Fardad; Ziejewski, Mariusz

    2014-01-01

    The results of a computational study of a helmeted human head are presented in this paper. The focus of the work is to study the effects of helmet pad materials on the level of acceleration, inflicted pressure and shear stress in a human brain model subjected to a ballistic impact. Four different closed cell foam materials, made of expanded polystyrene and expanded polypropylene, are examined for the padding material. It is assumed that bullets cannot penetrate the helmet shell. Finite element modelling of the helmet, padding system, head and head components is used for this dynamic nonlinear analysis. Appropriate contacts and conditions are applied between the different components of the head, as well as between the head and the pads, and the pads and the helmet. Based on the results of simulations in this work, it is concluded that the stiffness of the foam has a prominent role in reducing the level of the transferred load to the brain. A pad that is less stiff is more efficient in absorbing the impact energy and reducing the sudden acceleration of the head and consequently lowers the brain injury level. Using the pad with the least stiffness, the influence of the angle of impacts as well as the locations of the ballistic strike is studied.

  3. EI Scale: an environmental impact assessment scale related to the construction materials used in the reinforced concrete

    Directory of Open Access Journals (Sweden)

    Gilson Morales

    2010-12-01

    Full Text Available This study aimed to create EI Scal, an environmental impact assessment scal, related to construction materials used in the reinforced concrete structure production. The main reason for that was based on the need to classify the environmental impact levels through indicators to assess the damage level process. The scale allowed converting information to estimate the environmental impact caused. Indicators were defined trough the requirements and classification criteria of impact aspects considering the eco-design theory. Moreover, the scale allowed classifying the materials and processes environmental impact through four score categories which resulted in a single final impact score. It was concluded that the EI scale could be cheap, accessible, and relevant tool for environmental impact controlling and reduction, allowing the planning and material specification to minimize the construction negative effects caused in the environment.

  4. Dropping the Ball: The effect of anisotropic granular materials on ejecta and impact crater shape

    CERN Document Server

    Drexler, Philip; Arratia, Paulo

    2013-01-01

    In this fluid dynamics video, we present an experimental investigation of the shape of impact craters in granular materials. Complex crater shapes, including polygons, have been observed in many terrestrial planets as well as moons and asteroids. We release spherical projectiles from different heights above a granular bed (sand). The experiments demonstrate two different techniques to create non-circular impact craters, which we measure by digitizing the final crater topography. In the first method, we create trenches in the sand to mimic fault lines or valleys on a planetary target. During impact, ejecta move faster in the direction of the trenches, creating nearly elliptical craters with the major axis running parallel to the trench. Larger trenches lead to more oblong craters. In the second method, a hose beneath the surface of the sand injects nitrogen gas. The pressure of the gas counters the hydrostatic pressure of the sand, greatly reducing static friction between grains above the injection point, with...

  5. Environmental impacts of post-consumer material managements: recycling, biological treatments, incineration.

    Science.gov (United States)

    Valerio, F

    2010-11-01

    The environmental impacts of recycling, mechanical biological treatments (MBT) and waste-to-energy incineration, the main management strategies to respond to the increasing production of post-consumer materials are reviewed and compared. Several studies carried out according to life-cycle assessment (LCA) confirm that the lowest environmental impact, on a global scale, is obtained by recycling and by biological treatments (composting and anaerobic fermentations) if compost is used in agriculture. The available air emission factors suggest that, on a local scale, mechanical biological treatments with energy recovery of biogas, may be intrinsically safer than waste-to-energy incinerators. Several studies confirm the capability of biological treatments to degrade many toxic xenobiotic contaminating urban wastes such as dioxins and polycyclic aromatic hydrocarbons, an important property to be improved, for safe agricultural use of compost. Further LCA studies to compare the environmental impact of MBTs and of waste-to-energy incinerators are recommended.

  6. Hypervelocity impact tests on Space Shuttle Orbiter RCC thermal protection material. [Reinforced Carbon-Carbon laminate

    Science.gov (United States)

    Humes, D. H.

    1978-01-01

    It is noted that the Shuttle Orbiter will be more subject to meteoroid impact than previous spacecraft, due to its greater surface area and longer cumulative time in space. The Orbiter structural material, RCC, a reinforced carbon-carbon laminate with a diffused silicon carbide coating, is evaluated in terms of its resistance to hypervelocity impact. It was found that the specimens (disks with a mass of 34 g and a thickness of 5.0 mm) were cratered only on the front surface when the impact energy was 3 J or less. At 3 J, a trace of the black carbon interior was exposed. The specimens were completely penetrated when the energy was 34 J or greater.

  7. The Impact of Authentic Listening Materials on Elementary EFL Learners’ Listening Skills

    Directory of Open Access Journals (Sweden)

    Masoud Khalili Sabet

    2012-09-01

    Full Text Available Listening is one of the most pivotal skills, though; it is unjustly neglected throughout the literature. It was previously considered as passive skill but now those myths have been demystified. Therefore seeking the innovative trends for teaching and developing listening for EFL students are taken for granted. Lack of adequate exposure to listening and dearth of attention with regard to these issues sets the ground for authentic listening materials to fill the cited gaps in Iranian context. There have been controversial ideas based on studies in dealing with authentic listening materials. Their results ranged from totally abstinence to completely utilizing. This study intends to investigate the impact of authentic listening materials on listening skills of Elementary students at university level. To this aim, sixty students of university were randomly assigned to two groups. One group   was exposed to and received authentic listening materials (experimental group and the other groups received simplified listening materials (control group. A proficiency test (consisted of two sub-tests; listening comprehension and listening perception was used as a pretest to measure the students’ potential differences at outset of study. After the instruction sessions the same proficiency test was administered for both groups. Besides students feedback survey was given to experimental group to evaluate their attitudes and opinions regarding the materials. Analysis of quantitative study and comparing the mean scores of two groups via t-test showed that students who were exposed to authentic materials performed better in posttest. The analysis of feedback survey also denoted their satisfaction and positive attitudes to authentic listening materials. Keywords: Listening Skills, Authentic Listening Materials, EFL, Elementary

  8. Limitations to the Use of Species-Distribution Models for Environmental-Impact Assessments in the Amazon.

    Directory of Open Access Journals (Sweden)

    Lorena Ribeiro de A Carneiro

    Full Text Available Species-distribution models (SDM are tools with potential to inform environmental-impact studies (EIA. However, they are not always appropriate and may result in improper and expensive mitigation and compensation if their limitations are not understood by decision makers. Here, we examine the use of SDM for frogs that were used in impact assessment using data obtained from the EIA of a hydroelectric project located in the Amazon Basin in Brazil. The results show that lack of knowledge of species distributions limits the appropriate use of SDM in the Amazon region for most target species. Because most of these targets are newly described and their distributions poorly known, data about their distributions are insufficient to be effectively used in SDM. Surveys that are mandatory for the EIA are often conducted only near the area under assessment, and so models must extrapolate well beyond the sampled area to inform decisions made at much larger spatial scales, such as defining areas to be used to offset the negative effects of the projects. Using distributions of better-known species in simulations, we show that geographical-extrapolations based on limited information of species ranges often lead to spurious results. We conclude that the use of SDM as evidence to support project-licensing decisions in the Amazon requires much greater area sampling for impact studies, or, alternatively, integrated and comparative survey strategies, to improve biodiversity sampling. When more detailed distribution information is unavailable, SDM will produce results that generate uncertain and untestable decisions regarding impact assessment. In many cases, SDM is unlikely to be better than the use of expert opinion.

  9. Limitations to the Use of Species-Distribution Models for Environmental-Impact Assessments in the Amazon.

    Science.gov (United States)

    Carneiro, Lorena Ribeiro de A; Lima, Albertina P; Machado, Ricardo B; Magnusson, William E

    2016-01-01

    Species-distribution models (SDM) are tools with potential to inform environmental-impact studies (EIA). However, they are not always appropriate and may result in improper and expensive mitigation and compensation if their limitations are not understood by decision makers. Here, we examine the use of SDM for frogs that were used in impact assessment using data obtained from the EIA of a hydroelectric project located in the Amazon Basin in Brazil. The results show that lack of knowledge of species distributions limits the appropriate use of SDM in the Amazon region for most target species. Because most of these targets are newly described and their distributions poorly known, data about their distributions are insufficient to be effectively used in SDM. Surveys that are mandatory for the EIA are often conducted only near the area under assessment, and so models must extrapolate well beyond the sampled area to inform decisions made at much larger spatial scales, such as defining areas to be used to offset the negative effects of the projects. Using distributions of better-known species in simulations, we show that geographical-extrapolations based on limited information of species ranges often lead to spurious results. We conclude that the use of SDM as evidence to support project-licensing decisions in the Amazon requires much greater area sampling for impact studies, or, alternatively, integrated and comparative survey strategies, to improve biodiversity sampling. When more detailed distribution information is unavailable, SDM will produce results that generate uncertain and untestable decisions regarding impact assessment. In many cases, SDM is unlikely to be better than the use of expert opinion.

  10. Olivine or Impact Melt: Nature of the "Orange" Material on Vesta from Dawn

    CERN Document Server

    Corre, Lucille Le; Schmedemann, Nico; Becker, Kris J; O'Brien, David P; Yamashita, Naoyuki; Peplowski, Patrick N; Prettyman, Thomas H; Li, Jian-Yang; Cloutis, Edward A; Denevi, Brett W; Kneissl, Thomas; Palmer, Eric; Gaskell, Robert W; Nathues, Andreas; Gaffey, Michael J; Mittlefehldt, David W; Garry, William B; Sierks, Holger; Russell, Christopher T; Raymond, Carol A

    2013-01-01

    NASA's Dawn mission observed a great variety of colored terrains on asteroid (4) Vesta during its survey with the Framing Camera (FC). Here we present a detailed study of the orange material on Vesta, which was first observed in color ratio images obtained by the FC and presents a red spectral slope. The orange material deposits can be classified into three types, a) diffuse ejecta deposited by recent medium-size impact craters (such as Oppia), b) lobate patches with well-defined edges, and c) ejecta rays from fresh-looking impact craters. The location of the orange diffuse ejecta from Oppia corresponds to the olivine spot nicknamed "Leslie feature" first identified by Gaffey (1997) from ground-based spectral observations. The distribution of the orange material in the FC mosaic is concentrated on the equatorial region and almost exclusively outside the Rheasilvia basin. Our in-depth analysis of the composition of this material uses complementary observations from FC, the visible and infrared spectrometer (VI...

  11. Spatiotemporal Observation of Electron-Impact Dynamics in Photovoltaic Materials Using 4D Electron Microscopy

    KAUST Repository

    Shaheen, Basamat

    2017-05-17

    Understanding light-triggered charge carrier dynamics near photovoltaic-material surfaces and at interfaces has been a key element and one of the major challenges for the development of real-world energy devices. Visualization of such dynamics information can be obtained using the one-of-a-kind methodology of scanning ultrafast electron microscopy (S-UEM). Here, we address the fundamental issue of how the thickness of the absorber layer may significantly affect the charge carrier dynamics on material surfaces. Time-resolved snapshots indicate that the dynamics of charge carriers generated by electron impact in the electron-photon dynamical probing regime is highly sensitive to the thickness of the absorber layer, as demonstrated using CdSe films of different thicknesses as a model system. This finding not only provides the foundation for potential applications of S-UEM to a wide range of devices in the fields of chemical and materials research, but also has impact on the use and interpretation of electron beam-induced current for optimization of photoactive materials in these devices.

  12. Limiting overselling in international emissions trading 1: Costs and environmental impacts of alternative proposals

    Energy Technology Data Exchange (ETDEWEB)

    Haites, E.; Missfeldt, F.

    2002-07-01

    Emission trading allows a country with an emission limitation commitment, an Annex B Party, to sell parts of its assigned amount (AAUs) to other Annex B Parties. If the seller subsequently does not have sufficient AAUs to cover its actual emissions it will be subject to the penalties for non-compliance. The revenue from the sale of AAUs may exceed the sanctions for non-compliance if these penalties are weak or difficult to enforce. Under these circumstances emission trading enables a country to benefit financially through non-compliance. Liability proposals seek to ensure that non-compliance is not rewarded, by limiting sales of AAUs to amounts surplus to the seller's compliance needs. This study develops and applies a model to assess the performance of different liability proposals. A simple model based on the Emissions Projection and Policy Analysis (EPPA) model of the Massachusetts Institute of Technology is used for the analysis. (BA)

  13. Increasing P limitation and viral infection impact lipid remodeling of the picophytoplankter Micromonas pusilla

    Science.gov (United States)

    Maat, Douwe S.; Bale, Nicole J.; Hopmans, Ellen C.; Sinninghe Damsté, Jaap S.; Schouten, Stefan; Brussaard, Corina P. D.

    2016-03-01

    The intact polar lipid (IPL) composition of phytoplankton is plastic and dependent on environmental factors. Previous studies have shown that phytoplankton under low phosphorus (P) availability substitutes phosphatidylglycerols (PGs) with sulfoquinovosyldiacylglycerols (SQDGs) and digalactosyldiacylglycerols (DGDGs). However, these studies focused merely on P depletion, while phytoplankton in the natural environment often experience P limitation whereby the strength depends on the supply rate of the limiting nutrient. Here we report on the IPL composition of axenic cultures of the picophotoeukaryote Micromonas pusilla under different degrees of P limitation, i.e., P-controlled chemostats at 97 and 32 % of the maximum growth rate, and P starvation (obtained by stopping P supply to these chemostats). P-controlled cultures were also grown at elevated partial carbon dioxide pressure (pCO2) to mimic a future scenario of strengthened vertical stratification in combination with ocean acidification. Additionally, we tested the influence of viral infection for this readily infected phytoplankton host species. Results show that both SQDG : PG and DGDG : PG ratios increased with enhanced P limitation. Lipid composition was, however, not affected by enhanced (750 vs. 370 µatm) pCO2. In the P-starved virally infected cells the increase in SQDG : PG and DGDG : PG ratios was lower, whereby the extent depended on the growth rate of the host cultures before infection. The lipid membrane of the virus MpV-08T itself lacked some IPLs (e.g., monogalactosyldiacylglycerols; MGDGs) in comparison with its host. This study demonstrates that, besides P concentration, also the P supply rate, viral infection and even the history of the P supply rate can affect phytoplankton lipid composition (i.e., the non-phospholipid : phospholipid ratio), with possible consequences for the nutritional quality of phytoplankton.

  14. The Impact of Nitrogen Limitation and Mycorrhizal Symbiosis on Aspen Tree Growth and Development

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Bich Thi Ngoc [Univ. of Alabama, Huntsville, AL (United States)

    2014-08-18

    Nitrogen deficiency is the most common and widespread nutritional deficiency affecting plants worldwide. Ectromycorrhizal symbiosis involves the beneficial interaction of plants with soil fungi and plays a critical role in nutrient cycling, including the uptake of nitrogen from the environment. The main goal of this study is to understand how limiting nitrogen in the presence or absence of an ectomycorrhizal fungi, Laccaria bicolor, affects the health of aspen trees, Populus temuloides.

  15. Environmental, economic, and energy impacts of material recovery facilities. A MITE Program evaluation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-10-01

    This report documents an evaluation of the environmental, economic, and energy impacts of material recovery facilities (MRFs) conducted under the Municipal Solid Waste Innovative Technology Evaluation (MITE) Program. The MITE Program is sponsored by the US Environmental Protection Agency to foster the demonstration and development of innovative technologies for the management of municipal solid waste (MSW). This project was also funded by the National Renewable Energy Laboratory (NREL). Material recovery facilities are increasingly being used as one option for managing a significant portion of municipal solid waste (MSW). The owners and operators of these facilities employ a combination of manual and mechanical techniques to separate and sort the recyclable fraction of MSW and to transport the separated materials to recycling facilities.

  16. New method of the polymeric material properties experimental investigation under powerful energy flux impact

    Science.gov (United States)

    Demidov, B. A.; Efremov, V. P.; Kalinin, Yu G.; Kazakov, E. D.; Metelkin, S. Yu; Petrov, V. A.; Potapenko, A. I.

    2015-11-01

    Investigation of the polymeric material properties under powerfull energy flux impact is relevant as for basic research (mathematical modeling of polymeric materials behavior in extreme conditions, testing the state equations), as for practical applications (for testing of protective coatings for space research and laboratory facilities). This paper presents the results of experimental studies of the interaction of polymeric materials with a relativistic electron beam produced by a high-current electron accelerator Calamary. Calamary facility provides a wide range of electron beam parameters: diameter 10-15 mm, the voltage on the diode up to 300 kV, the current through the diode up to 30 kA. New method of beam-target interaction area measurement was developed. The original method for the mechanical kick impulse measuring based on piezoelectric vibration sensor was presented. The dependence of the kick impulse from the power flux was obtained.

  17. Impact of Oils Sands Mining on Nitrogen-Limited Peatland Ecosystems in Alberta Canada

    Science.gov (United States)

    Vile, M. A.; Wieder, R.; Scott, K.; Prsa, T.; Quinn, J.; Vitt, D. H.

    2010-12-01

    Peatlands of boreal Canada represent large reservoirs of sequestered carbon (C) and nitrogen (N). Cycling of C and N in peatlands is intrinsically linked, especially in bogs - peatlands isolated from ground- and surface-water inputs, receiving nutrients exclusively from the atmosphere, which in the absence of N pollution, ensures an N-limited, nutrient-poor ecosystem. A growing concern associated with the development of Alberta’s Oil Sands Mining (OSM) is the potential for regionally elevated deposition of N-compounds (NOx). Prior to OSM, N inputs to bogs were limited exclusively to (1) biological N fixation, and (2) bulk atmospheric deposition. Currently, data examining the effect of purported increases in N and S deposition in this region are limited. Our goal was to determine patterns in atmospheric N deposition on N concentrations in bog porewaters at 5 sites spanning varying distances from the OSM region: Mildred, McKay, McMurray, Anzac and Utikuma bog (14, 24, 51, 71 and 300 km, respectively). Specifically, we wanted to test the hypothesis that OSM results in higher N deposition leading to elevated N in porewaters. Deposition of N was greatest at Mildred, followed by McKay, McMurray, and Anzac, and significantly lowest at Utikuma Bog (F4,49 = 5.9, p resin samplers placed at each site (n=50 total; 10 per site) and porewaters were collected using a modified sipper design (n=15; 3 per site; 10-10cm depth intervals per sipper).

  18. Satellite observations of the role and impacts of dry season climate limitations on tropical forest fates

    Science.gov (United States)

    Huete, A. R.; Restrepo-Coupe, N.; Wu, J.; Devadas, R.; Guan, K.; Liu, Y.; Ratana, P.; Sun, Q.; Schaaf, C.; Saleska, S. R.

    2015-12-01

    Climate change scenarios projected for the 21st century predict drying of the Amazon, greening of monsoon tropical Asia and no change in the tropics of Australia. Dry season variability is increasing with complex associated forest responses and feedbacks as they become exposed to longer and/or more intense dry seasons. The functional response of tropical forests to dry seasonal periods is thus crucial to forest resilience, as forests may respond with either enhanced photosynthesis (due to more sunlight) or may dry down with greater susceptibility to fires and release of greenhouse gases and severe public health haze alerts. In this study, we use multiple satellite remote sensing datasets representing forest canopy states, environmental drivers (light and water status), and disturbance (fires), along with in situ flux tower measures of photosynthesis to assess whole ecosystem patterns and test mechanisms of forest- dry season climate interactions. We compare photosynthesis patterns and dry season responses of Asia-Oceania tropical forests with neotropical forests to better understand forest resilience to climate change and human impacts. In contrast to the neotropics, human activities in monsoon tropical Asia have resulted in intensive transformations of tropical forests. We find forest disturbance exerts a strong influence on tropical forest functioning and a partial loss or degradation of tropical forests can reverse dry seasonal responses with substantial impacts on carbon fluxes. Neotropical forests displayed large variations in dry season forest responses due to spatially variable dry season lengths and magnitude, whereas most of monsoon Asia tropical forests lacked well-defined dry seasons, yet were highly sensitive to shorter term, intense drought events that impacted severely upon the disturbed forests. Our results highlight the interactions among rainfall, radiation and forest health with the relative importance of each factor varying with the

  19. The impact of mass transfer limitations on size distributions of particle associated SVOCs in outdoor and indoor environments

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Cong; Zhang, Yinping [Department of Building Science, Tsinghua University, Beijing (China); Weschler, Charles J., E-mail: weschlch@rwjms.rutgers.edu [Department of Building Science, Tsinghua University, Beijing (China); Environmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, NJ (United States); International Center for Indoor Environment and Energy, Technical University of Denmark, Lyngby (Denmark)

    2014-11-01

    Semi-volatile organic compounds (SVOCs) partition between the gas phase and airborne particles. The size distribution of particle-associated SVOCs impacts their fate in outdoor and indoor environments, as well as human exposure to these compounds and subsequent health risks. Allen et al. (1996) previously proposed that the rate of mass transfer can impact polycyclic aromatic hydrocarbon (PAH) partitioning among different sized particles, especially for time scales relevant to urban aerosols. The present study quantitatively builds on this idea, presenting a model that incorporates dynamic SVOC/particle interaction and applying this model to typical outdoor and indoor scenarios. The model indicates that the impact of mass transfer limitations on the size distribution of a particle-associated SVOC can be evaluated by the ratio of the time to achieve gas–particle equilibrium relative to the residence time of particles. The higher this ratio, the greater the influence of mass transfer limitations on the size distribution of particle-associated SVOCs. The influence of such constraints is largest on the fraction of particle-associated SVOCs in the coarse mode (> 2 μm). Predictions from the model have been found to be in reasonable agreement with size distributions measured for PAHs at roadside and suburban locations in Japan. The model also quantitatively explains shifts in the size distributions of particle associated SVOCs compared to those for particle mass, and the manner in which these shifts vary with temperature and an SVOC's molecular weight. - Highlights: • Rate of mass transfer can impact SVOC partitioning among different sized particles. • Model was developed that incorporates dynamic SVOC/particle sorption. • Key parameters: mass-transfer coefficients, partition coefficient, residence time • Model explains observed SVOC size distribution shifts with temperature and MW. • Largest impact of mass transfer constraints: SVOC sorption to coarse

  20. Investigation of Coupled Processes and Impact of High Temperature Limits in Argillite Rock

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Liange [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Rutqvist, Jonny [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kim, Kunhwi [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Houseworth, Jim [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-07-01

    The focus of research within the UFD Campaign is on repository-induced interactions that may affect the key safety characteristics of an argillaceous rock. These include thermal-hydrological-mechanical-chemical (THMC) process interactions that occur as a result of repository construction and waste emplacement. Some of the key questions addressed in this report include the development of fracturing in the excavation damaged zone (EDZ) and THMC effects on the near-field argillaceous rock and buffer minerals and petrophysical characteristics, particularly the impacts of induced temperature rise caused by waste heat.

  1. Impact of ideal MHD stability limits on high-beta hybrid operation

    Science.gov (United States)

    Piovesan, P.; Igochine, V.; Turco, F.; Ryan, D. A.; Cianciosa, M. R.; Liu, Y. Q.; Marrelli, L.; Terranova, D.; Wilcox, R. S.; Wingen, A.; Angioni, C.; Bock, A.; Chrystal, C.; Classen, I.; Dunne, M.; Ferraro, N. M.; Fischer, R.; Gude, A.; Holcomb, C. T.; Lebschy, A.; Luce, T. C.; Maraschek, M.; McDermott, R.; Odstrčil, T.; Paz-Soldan, C.; Reich, M.; Sertoli, M.; Suttrop, W.; Taylor, N. Z.; Weiland, M.; Willensdorfer, M.; The ASDEX Upgrade Team; The DIII-D Team; The EUROfusion MST1 Team

    2017-01-01

    The hybrid scenario is a candidate for stationary high-fusion gain tokamak operation in ITER and DEMO. To obtain such performance, the energy confinement and the normalized pressure {βN} must be maximized, which requires operating near or above ideal MHD no-wall limits. New experimental findings show how these limits can affect hybrid operation. Even if hybrids are mainly limited by tearing modes, proximity to the no-wall limit leads to 3D field amplification that affects plasma profiles, e.g. rotation braking is observed in ASDEX Upgrade throughout the plasma and peaks in the core. As a result, even the small ASDEX Upgrade error fields are amplified and their effects become visible. To quantify such effects, ASDEX Upgrade measured the response to 3D fields applied by 8× 2 non-axisymmetric coils as {βN} approaches the no-wall limit. The full n  =  1 response profile and poloidal structure were measured by a suite of diagnostics and compared with linear MHD simulations, revealing a characteristic feature of hybrids: the n  =  1 response is due to a global, marginally-stable n  =  1 kink characterized by a large m  =  1, n  =  1 core harmonic due to q min being just above 1. A helical core distortion of a few cm forms and affects various core quantities, including plasma rotation, electron and ion temperature, and intrinsic W density. In similar experiments, DIII-D also measured the effect of this helical core on the internal current profile, providing information useful to understanding of the physics of magnetic flux pumping, i.e. anomalous current redistribution by MHD modes that keeps {{q}\\text{min}}>1 . Thanks to flux pumping, a broad current profile is maintained in DIII-D even with large on-axis current drive, enabling fully non-inductive operation at high {βN} up to 3.5-4.

  2. EI Scale: an environmental impact assessment scale related to the construction materials used in the reinforced concrete

    OpenAIRE

    Gilson Morales; Antonio Edésio Jungles; Sheila Elisa Scheidemantel Klein; Juliana Guarda

    2010-01-01

    This study aimed to create EI Scal, an environmental impact assessment scal, related to construction materials used in the reinforced concrete structure production. The main reason for that was based on the need to classify the environmental impact levels through indicators to assess the damage level process. The scale allowed converting information to estimate the environmental impact caused. Indicators were defined trough the requirements and classification criteria of impact aspects consid...

  3. Nitrogen or phosphorus limitation in lakes and its impact on phytoplankton biomass and submerged macrophyte cover

    DEFF Research Database (Denmark)

    Søndergaard, Martin; Lauridsen, Torben Linding; Johansson, Liselotte Sander

    2017-01-01

    macrophyte cover. We conclude that P is of key importance for the ecological quality of Danish lakes but that increased N concentrations, particularly in shallow lakes with moderate to high TP, may have significantly adverse effects on lake water quality and ecological status in summer.......We used data on nutrients, chlorophyll a (Chla) and submerged macrophyte cover from up to 817 Danish lakes to elucidate seasonal variations in nitrogen (N) and phosphorus (P) concentrations and to study the impact of N or its role in combination with P. In both deep and shallow lakes, we found...... related more strongly to TP than to TN, but at high TP concentrations TN explained more of the variability in Chla than TP. Macrophyte cover tended to decrease at increasing TN when TP was between 0.1 and 0.4 mg/l. At macrophyte cover above 20%, Chla was considerably lower compared with lakes with low...

  4. ENVIRONMENTAL IMPACT OF LIMITATION ON USE OUTFLOW POLLUTION WITH RURAL FARM

    Directory of Open Access Journals (Sweden)

    Sławomir Szymczyk

    2014-10-01

    Full Text Available The intensity of the movement of mineral and organic substances in the agro-forestry catchment is decisive influenced by weather conditions. Intensive drainage caused an increase in the outflow of the substances of the farmstead. Rural farm located on light soils is a major source of groundwater contamination by organic and mineral substances. An important role in the through of pollutants migration played an ecological area, which contributed to a significant reduction in the concentration of the ash components, chlorides and sulfates in groundwater, and consequently reduced the negative impact of farmstead on the water quality in a nearby pond. Periodically functioning supply of forest area by groundwater of the midfield pond contributed to the deterioration of groundwater quality in the forest.

  5. Short, sharp shock public health campaign had limited impact on raising awareness of laryngeal cancer.

    Science.gov (United States)

    Sethi, Neeraj; Rafferty, Amy; Rawnsley, Trisha; Jose, Jemy

    2016-09-01

    Laryngeal cancer has poorer outcomes if diagnosed at a later stage. Improving awareness could encourage earlier presentation and improve outcomes. This study aimed to evaluate a public engagement campaign targeted at raising awareness of laryngeal cancer. An epidemiological study identified high-risk populations in the region. A target population as well as a matched control population was selected. A cancer awareness survey combined with focus groups guided the design of a 3-month multimedia campaign. The survey was repeated post-campaign to evaluate the campaign effectiveness. The study identified populations with the highest rates of laryngeal cancer and late stage disease at presentation. The surveys performed revealed a limited effect of the multimedia campaign in raising awareness of the signs and symptoms of laryngeal cancer. Recall of the campaign also faded rapidly. This is the first public awareness campaign aimed at laryngeal cancer carried out in the UK. The results suggest that short-term campaigns have a limited effect and a more prolonged approach should be considered.

  6. The contamination of the surface of Vesta by impacts and the delivery of the dark material

    CERN Document Server

    Turrini, D; McCord, T B; Oklay, N; Vincent, J -B; Prettyman, T H; McSween, H Y; SJ, G J Consolmagno; De Sanctis, M C; Corre, L Le; Longobardo, A; Palomba, E; Russell, C T

    2014-01-01

    The Dawn spacecraft observed the presence of dark material, which in turn proved to be associated with OH and H-rich material, on the surface of Vesta. The source of this dark material has been identified with the low albedo asteroids, but it is still a matter of debate whether the delivery of the dark material is associated with a few large impact events, to micrometeorites or to the continuous, secular flux of impactors on Vesta. The continuous flux scenario predicts that a significant fraction of the exogenous material accreted by Vesta should be due to non-dark impactors likely analogous to ordinary chondrites, which instead represent only a minor contaminant in the HED meteorites. We explored the continuous flux scenario and its implications for the composition of the vestan regolith, taking advantage of the data from the Dawn mission and the HED meteorites. We used our model to show that the stochastic events scenario and the micrometeoritic flux scenario are natural consequences of the continuous flux ...

  7. Study on Impact Acoustic—Visual Sensor-Based Sorting of ELV Plastic Materials

    Science.gov (United States)

    Huang, Jiu; Tian, Chuyuan; Ren, Jingwei; Bian, Zhengfu

    2017-01-01

    This paper concentrates on a study of a novel multi-sensor aided method by using acoustic and visual sensors for detection, recognition and separation of End-of Life vehicles’ (ELVs) plastic materials, in order to optimize the recycling rate of automotive shredder residues (ASRs). Sensor-based sorting technologies have been utilized for material recycling for the last two decades. One of the problems still remaining results from black and dark dyed plastics which are very difficult to recognize using visual sensors. In this paper a new multi-sensor technology for black plastic recognition and sorting by using impact resonant acoustic emissions (AEs) and laser triangulation scanning was introduced. A pilot sorting system which consists of a 3-dimensional visual sensor and an acoustic sensor was also established; two kinds commonly used vehicle plastics, polypropylene (PP) and acrylonitrile-butadiene-styrene (ABS) and two kinds of modified vehicle plastics, polypropylene/ethylene-propylene-diene-monomer (PP-EPDM) and acrylonitrile-butadiene-styrene/polycarbonate (ABS-PC) were tested. In this study the geometrical features of tested plastic scraps were measured by the visual sensor, and their corresponding impact acoustic emission (AE) signals were acquired by the acoustic sensor. The signal processing and feature extraction of visual data as well as acoustic signals were realized by virtual instruments. Impact acoustic features were recognized by using FFT based power spectral density analysis. The results shows that the characteristics of the tested PP and ABS plastics were totally different, but similar to their respective modified materials. The probability of scrap material recognition rate, i.e., the theoretical sorting efficiency between PP and PP-EPDM, could reach about 50%, and between ABS and ABS-PC it could reach about 75% with diameters ranging from 14 mm to 23 mm, and with exclusion of abnormal impacts, the actual separation rates were 39.2% for PP, 41

  8. Threshold Studies of Heated HMX-Based Energetic Material Targets Using the Steven Impact Test

    Energy Technology Data Exchange (ETDEWEB)

    Switzer, L L; Vandersall, K S; Chidester, S K; Greenwood, D W; Tarver, C M

    2003-07-01

    Impact tests performed at low velocity on heated energetic material samples are of interest when considering the situation of energetic materials involved in a fire. To determine heated reaction thresholds, Steven Test targets containing PBX 9404 or LX-04 samples heated to the range of 150-170 C were impacted at velocities up to 150 m/s by two different projectile head geometries. Comparing these measured thresholds to ambient temperature thresholds revealed that the heated LX-04 thresholds were considerably higher than ambient, whereas the heated PBX 9404 thresholds were only slightly higher than the ambient temperature thresholds. The violence of reaction level of the PBX 9404 was considerably higher than that of the LX-04 as measured with four overpressure gauges. The varying results in these samples with different HMX/binder configurations indicate that friction plays a dominant role in reaction ignition during impact. This work outlines the experimental details, compares the thresholds and violence levels of the heated and ambient temperature experiments, and discusses the dominant mechanisms of the measured thresholds.

  9. The sensitivity of the burst performance of impact damaged pressure vessels to material strength properties

    Science.gov (United States)

    Lasn, K.; Vedvik, N. P.; Echtermeyer, A. T.

    2016-07-01

    This numerical study is carried out to improve the understanding of short-term residual strength of impacted composite pressure vessels. The relationship between the impact, created damage and residual strength is predicted by finite element (FE) analysis. The burst predictions depend largely on the strength properties used in the material models. However, it is typically not possible to measure all laminate properties on filament wound structures. Reasonable testing efforts are concentrated on critical properties, while obtaining other less sensitive parameters from e.g. literature. A parametric FE model is hereby employed to identify the critical strength properties, focusing on the cylindrical section of the pressure vessel. The model simulates an impactor strike on an empty vessel, which is subsequently pressurized until burst. Monte Carlo Simulations (MCS) are employed to investigate the correlations between strength related material parameters and the burst pressure. The simulations indicate the fracture toughness of the composite, hoop layer tensile strength and the yield stress of the PE liner as the most influential parameters for current vessel and impact configurations. In addition, the conservative variation in strength parameters is shown to have a rather moderate effect (COV ca. 7%) on residual burst pressures.

  10. Digital image analysis of ASB-assisted failure of impacted structural materials

    Directory of Open Access Journals (Sweden)

    Longère Patrice

    2015-01-01

    Full Text Available Experimental analysis of fracture mechanisms is a key point to understand and further reproduce physical phenomena involved in structural material failure. Actually, crack propagation under high loading rate is a strongly coupled thermo-mechanical problem involving large deformation, high strain rate and (quasi adiabatic conditions. The work presented herein aims at analyzing the successive steps of the dynamic deterioration of a high strength structural material, namely the ARMOX500T armor steel, leading to the ultimate fracture. The Kalthoff and Winkler impact test, consisting in impacting the edge of a double notched plate, was retained for that purpose. Images are captured at high frame rate (1M frame/s during the impact loading then analyzed according to a line tracking method. Three stages are accordingly observed: first the progressive development of a weak localization of the deformation within a wide zone behind the notch tips, second the propagation of a narrow band of strong localization, and finally the propagation of a crack. The propagation of the white band is associated to the development of an adiabatic shear band (ASB, as a precursor of the crack. Corresponding displacement fields are identified thanks to the adopted line tracking method, allowing for determining the evolution of mechanical quantities, including notably notch tip shear displacement and velocity, ASB-related white band velocity, global and local shear strain and shear strain rate magnitudes, in view of being implemented into numerical models.

  11. Physiological impacts of ABA-JA interactions under water-limitation.

    Science.gov (United States)

    de Ollas, Carlos; Dodd, Ian C

    2016-08-01

    Plant responses to drought stress depend on highly regulated signal transduction pathways with multiple interactions. This complex crosstalk can lead to a physiological outcome of drought avoidance or tolerance/resistance. ABA is the principal mediator of these responses due to the regulation of stomatal closure that determines plant growth and survival, but also other strategies of drought resistance such as osmotic adjustment. However, other hormones such as JA seem responsible for regulating a subset of plant responses to drought by regulating ABA biosynthesis and accumulation and ABA-dependent signalling, but also by ABA independent pathways. Here, we review recent reports of ABA-JA hormonal and molecular interactions within a physiological framework of drought tolerance. Understanding the physiological significance of this complex regulation offers opportunities to find strategies of drought tolerance that avoid unwanted side effects that limit growth and yield, and may allow biotechnological crop improvement.

  12. Impact of field limiting ring technique on breakdown voltage of irradiated Si sensors

    CERN Document Server

    Bhardwaj, Ashutosh; Jha Manoj, Kr; Kumar, Ashish; Ranjan, Kirti; Shivpuri, RK; Srivastava-Ajay, K

    2003-01-01

    The very intense radiation environment of high luminosity future colliding beam experiments (like LHC) makes radiation hardness the most important issue for Si detectors. One of the central issues concerning all LHC experiments is the breakdown performance of these detectors. The major macroscopic effect of radiation damage in determining the viability of long-term operation of Si sensors is the change in effective charge carrier concentration (N //e//f//f), leading to type-inversion. Floating field limiting guard rings have been established as means of improving the breakdown performance of Si detectors. In this work the usefulness of the guard rings in improving the breakdown performance of detectors after type-inversion has been studied. Simulations are carried out to study the effect of change in N//e//f//f on the breakdown performance of optimized guard ring structure using two dimensional device simulation program, TMA- MEDICI. Detailed calculations using Hamburg Model have allowed the parameterization ...

  13. Impact of field limiting ring technique on breakdown voltage of irradiated Si sensors

    CERN Document Server

    Bhardwaj, A; Namrata, S; Chatterji, S; Srivastava-Ajay, K; Kumar, A; Jha, Manoj Kumar; Shivpuri, R K

    2004-01-01

    The very intense radiation environment of high luminosity future colliding beam experiments (like LHC) makes radiation hardness the most important issue for Si detectors. One of the central issues concerning all LHC experiments is the breakdown performance of these detectors. The major macroscopic effect of radiation damage in determining the viability of long-term operation of Si sensors is the change in effective charge carrier concentration (N/sub eff/), leading to type-inversion. Floating field limiting guard rings have been established as means of improving the breakdown performance of Si detectors. In this work the usefulness of the guard rings in improving the breakdown performance of detectors after type-inversion has been studied. Simulations are carried out to study the effect of change in N/sub eff/ on the breakdown performance of optimized guard ring structure using two dimensional device simulation program, TMA- MEDICI. Detailed calculations using Hamburg Model have allowed the parameterization o...

  14. Stabilization/solidification of battery debris & lead impacted material at Schuylkill Metals, Plant City, Florida

    Energy Technology Data Exchange (ETDEWEB)

    Anguiano, T.; Floyd, D. [ENTACT, Inc., Irving, TX (United States)

    1997-12-31

    The Schuylkill Metals facility in Plant City Florida (SMPCI) operated as a battery recycling facility for approximately 13 years. During its operation, the facility disposed of battery components in surrounding wetland areas. In March of 1991 the U.S. EPA and SMPCI entered into a Consent Decree for the remediation of the SMPCI site using stabilization/solidification and on-site disposal. In November of 1994, ENTACT began remediation at the facility and to date has successfully stabilized/solidified over 228,000 tons of lead impacted battery components and lead impacted material. The ENTACT process reduces the size of the material to be treated to ensure that complete mixing of the phosphate/cement additive is achieved thereby promoting the chemical reactions of stabilization and solidification. ENTACT has met the following performance criteria for treated material at the SMPCI site: (1) Hydraulic Conductivity less than 1x10{sup -6} cm/s, (2) Unconfined Compressive Strength greater than 50 psi, (3) Lead, Cadmium, Arsenic, Chromium TCLP Leachability below hazardous levels.

  15. Maternal health interventions in resource limited countries: a systematic review of packages, impacts and factors for change

    Science.gov (United States)

    2011-01-01

    Background The burden of maternal mortality in resource limited countries is still huge despite being at the top of the global public health agenda for over the last 20 years. We systematically reviewed the impacts of interventions on maternal health and factors for change in these countries. Methods A systematic review was carried out using the guidelines for Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Articles published in the English language reporting on implementation of interventions, their impacts and underlying factors for maternal health in resource limited countries in the past 23 years were searched from PubMed, Popline, African Index Medicus, internet sources including reproductive health gateway and Google, hand-searching, reference lists and grey literature. Results Out of a total of 5084 articles resulting from the search only 58 qualified for systematic review. Programs integrating multiple interventions were more likely to have significant positive impacts on maternal outcomes. Training in emergency obstetric care (EmOC), placement of care providers, refurbishment of existing health facility infrastructure and improved supply of drugs, consumables and equipment for obstetric care were the most frequent interventions integrated in 52% - 65% of all 54 reviewed programs. Statistically significant reduction of maternal mortality ratio and case fatality rate were reported in 55% and 40% of the programs respectively. Births in EmOC facilities and caesarean section rates increased significantly in 71% - 75% of programs using these indicators. Insufficient implementation of evidence-based interventions in resources limited countries was closely linked to a lack of national resources, leadership skills and end-users factors. Conclusions This article presents a list of evidenced-based packages of interventions for maternal health, their impacts and factors for change in resource limited countries. It indicates that no single

  16. Maternal health interventions in resource limited countries: a systematic review of packages, impacts and factors for change.

    Science.gov (United States)

    Nyamtema, Angelo S; Urassa, David P; van Roosmalen, Jos

    2011-04-17

    The burden of maternal mortality in resource limited countries is still huge despite being at the top of the global public health agenda for over the last 20 years. We systematically reviewed the impacts of interventions on maternal health and factors for change in these countries. A systematic review was carried out using the guidelines for Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Articles published in the English language reporting on implementation of interventions, their impacts and underlying factors for maternal health in resource limited countries in the past 23 years were searched from PubMed, Popline, African Index Medicus, internet sources including reproductive health gateway and Google, hand-searching, reference lists and grey literature. Out of a total of 5084 articles resulting from the search only 58 qualified for systematic review. Programs integrating multiple interventions were more likely to have significant positive impacts on maternal outcomes. Training in emergency obstetric care (EmOC), placement of care providers, refurbishment of existing health facility infrastructure and improved supply of drugs, consumables and equipment for obstetric care were the most frequent interventions integrated in 52%-65% of all 54 reviewed programs. Statistically significant reduction of maternal mortality ratio and case fatality rate were reported in 55% and 40% of the programs respectively. Births in EmOC facilities and caesarean section rates increased significantly in 71%-75% of programs using these indicators. Insufficient implementation of evidence-based interventions in resources limited countries was closely linked to a lack of national resources, leadership skills and end-users factors. This article presents a list of evidenced-based packages of interventions for maternal health, their impacts and factors for change in resource limited countries. It indicates that no single magic bullet intervention exists for

  17. Maternal health interventions in resource limited countries: a systematic review of packages, impacts and factors for change

    Directory of Open Access Journals (Sweden)

    Urassa David P

    2011-04-01

    Full Text Available Abstract Background The burden of maternal mortality in resource limited countries is still huge despite being at the top of the global public health agenda for over the last 20 years. We systematically reviewed the impacts of interventions on maternal health and factors for change in these countries. Methods A systematic review was carried out using the guidelines for Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA. Articles published in the English language reporting on implementation of interventions, their impacts and underlying factors for maternal health in resource limited countries in the past 23 years were searched from PubMed, Popline, African Index Medicus, internet sources including reproductive health gateway and Google, hand-searching, reference lists and grey literature. Results Out of a total of 5084 articles resulting from the search only 58 qualified for systematic review. Programs integrating multiple interventions were more likely to have significant positive impacts on maternal outcomes. Training in emergency obstetric care (EmOC, placement of care providers, refurbishment of existing health facility infrastructure and improved supply of drugs, consumables and equipment for obstetric care were the most frequent interventions integrated in 52% - 65% of all 54 reviewed programs. Statistically significant reduction of maternal mortality ratio and case fatality rate were reported in 55% and 40% of the programs respectively. Births in EmOC facilities and caesarean section rates increased significantly in 71% - 75% of programs using these indicators. Insufficient implementation of evidence-based interventions in resources limited countries was closely linked to a lack of national resources, leadership skills and end-users factors. Conclusions This article presents a list of evidenced-based packages of interventions for maternal health, their impacts and factors for change in resource limited countries

  18. Evaluating Opportunities to Improve Material and Energy Impacts in Commodity Supply Chains.

    Energy Technology Data Exchange (ETDEWEB)

    Hanes, Rebecca J.; Carpenter, Alberta

    2016-06-28

    When evaluated at the process level, next-generation technologies may be more energy and emissions intensive than current technology. However, many advanced technologies have the potential to reduce material and energy consumption in upstream or downstream processing stages. In order to fully understand the benefits and consequences of technology deployment, next-generation technologies should be evaluated in context, as part of a supply chain. This work presents the Material Flows through Industry (MFI) scenario modeling tool. The MFI tool is a cradle-to-gate linear network model of the U.S. industrial sector that can model a wide range of manufacturing scenarios, including changes in production technology, increases in industrial energy efficiency, and substitution between functionally equivalent materials. The MFI tool was developed to perform supply chain scale analyses in order to quantify the impacts and benefits of next-generation technologies and materials at that scale. For the analysis presented in this paper, the MFI tool is utilized to explore a case study comparing a steel supply chain to the supply chains of several functionally equivalent materials. Several of the alternatives to the baseline steel supply chain include next-generation production technologies and materials. Results of the case study show that aluminum production scenarios can out-perform the steel supply chain by using either an advanced smelting technology or an increased aluminum recycling rate. The next-generation material supply chains do not perform as well as either aluminum or steel, but may offer additional use phase reductions in energy and emissions that are outside the scope of the MFI tool. Future work will combine results from the MFI tool with a use phase analysis.

  19. The Impact of Social Media on Press Freedom in Greece: Benefits, Challenges and Limitations

    Directory of Open Access Journals (Sweden)

    Katerina SERAFEIM

    2012-01-01

    Full Text Available The purpose of the essay is to put light on the expansion of social media in news broadcasting in Greece, highlighting their impact on press freedom and freedom of expression. Taken for granted that the media in Greece (television, radio and print press have created, except from their “traditional version”, social media profiles (facebook profile, twitter etc. in order to disseminate the news, the essay investigates the interconnection between the aforementioned use of social media and press freedom. In addition, special focus is given to the challenges that appear from the emergence of social media as news platforms and to the debate that has occurred “for” and “against” this new role of them. Moreover, the essay puts light to some crucial questions that arise:Do social media in Greece, as news platforms, extend freedom of expression and how do they accomplish that? Does the fact that social media empower journalists to provide journalism in more ways than one through tweets, postings, and video and photo uploads, enhance journalists’ freedom of expression and, in a wider sense, the freedom of the press? Has the invasion of social media in the news flow and coverage changed the media landscape in Greece?

  20. What Has Limited the Impact of UK Disability Equality Law on Social Justice?

    Directory of Open Access Journals (Sweden)

    Rupert Harwood

    2016-11-01

    Full Text Available The literature indicates that disabled workers in the UK experience more social injustice than UK workers as a whole, including in relation to employment rates and wage levels. Drawing on the author’s 2015 qualitative study of 265 disabled workers, this paper considers how successful the Equality Act 2010 Reasonable Adjustments Duty has been in tackling this social injustice. It finds that in the context of the “flexible” labour force (consisting of insecure jobs, and the “reformed” welfare state, the Reasonable Adjustments Duty is ill-equipped to achieve its original purpose of reducing the substantial disadvantage that disabled workers face. As regards the “flexible” labour force, there appeared, for example, to be a strong reluctance to make reasonable adjustments for workers on zero hours contracts; while, as regards the impact of welfare reform, fear of being dismissed and facing benefit sanctions discouraged zero hours workers from pushing for adjustments which had been refused. The paper goes on to suggest a possible wording for a strengthened Reasonable Adjustments Duty. It concludes, however, that, without changes to unfair dismissal, and other labour laws, to address the wider iniquities of the flexible labour market, a strengthened duty will not be able to prevent a long term increase in social injustice for disabled workers.

  1. Mitigation of plasma–material interactions via passive Li efflux from the surface of a flowing liquid lithium limiter in EAST

    Science.gov (United States)

    Zuo, G. Z.; Hu, J. S.; Maingi, R.; Ren, J.; Sun, Z.; Yang, Q. X.; Chen, Z. X.; Xu, H.; Tritz, K.; Zakharov, L. E.; Gentile, C.; Meng, X. C.; Huang, M.; Xu, W.; Chen, Y.; Wang, L.; Yan, N.; Mao, S. T.; Yang, Z. D.; Li, J. G.; EAST Team

    2017-04-01

    A new flowing liquid Li limiter (FLiLi) based on the concept of a thin flowing film has been successfully designed and tested in the EAST device in 2014. A bright Li radiative mantle at the plasma edge was observed during discharges using FLiLi, resulting from passive Li injection and transport in the scrape-off layer (SOL) plasma. Li particle efflux from the FLiLi surface into the plasma was estimated at  >5  ×  1020 atom s‑1, due to surface evaporation and sputtering, and accompanied with a few small Li droplets ~1 mm diameter that were ejected from FLiLi. The Li efflux from FLiLi was ionized by the SOL plasma and formed a Li radiation band that originated from the FLiLi surface, and then spread toroidally by SOL plasma flow. The Li radiative mantle appeared to partly isolate the plasma from the wall, reducing impurity release from the wall materials, and possibly leading to a modest improvement in confinement. In addition, strong Li radiation reduced the particle and heat fluxes impacting onto the divertor plate, with certain similarities to heat flux reduction and detachment onset via low-Z impurity injection.

  2. Impact and hardness optimisation of composite materials inspired by the babassu nut (Orbignya speciosa).

    Science.gov (United States)

    Staufenberg, Gerrit; Graupner, Nina; Müssig, Jörg

    2015-08-20

    The babassu nut is the fruit of the babassu palm Orbignya speciosa. The combination of hardness and impact strength is difficult to acquire for artificial materials, making the babassu nut a promising source for biomimetic inspiration. Unnotched Charpy impact tests, Shore D hardness tests and scanning electron microscopy were used for mechanical and microscopical analysis of the pericarp. Four major principles were found for a biomimetic approach: a hard core ((1); endocarp) is embedded in a soft outer layer of high impact strength ((2); epicarp) and is reinforced with fibres of variable fineness (3), some of which are oriented radial to the core (4). Biomimetic fibre-reinforced composites were produced using abstracted mechanisms of the babassu nut based on regenerated cellulose fibres (lyocell, L) with two different fineness values as reinforcement embedded in a polylactide (PLA) core matrix and polypropylene (PP) based outer layers. The biomimetic fibre composite reaches a significantly higher impact strength that is 1.6 times higher than the reference sample produced from a PLA/PP/L-blend. At the same time the hardness is slightly increased compared to PP/L.

  3. An experimental study of low-velocity impacts into granular material in reduced gravity

    Science.gov (United States)

    Murdoch, Naomi; Avila Martinez, Iris; Sunday, Cecily; Zenou, Emmanuel; Cherrier, Olivier; Cadu, Alexandre; Gourinat, Yves

    2017-01-01

    In order to improve our understanding of landing on small bodies and of asteroid evolution, we use our novel drop tower facility (Sunday et al. 2016) to perform low-velocity (2 - 40 cm/s), shallow impact experiments of a 10 cm diameter aluminum sphere into quartz sand in low effective gravities (˜0.2 - 1 m/s2). Using in-situ accelerometers we measure the acceleration profile during the impacts and determine the peak accelerations, collision durations and maximum penetration depth. We find that the penetration depth scales linearly with the collision velocity but is independent of the effective gravity for the experimental range tested, and that the collision duration is independent of both the effective gravity and the collision velocity. No rebounds are observed in any of the experiments. Our low-gravity experimental results indicate that the transition from the quasi-static regime to the inertial regime occurs for impact energies two orders of magnitude smaller than in similar impact experiments under terrestrial gravity. The lower energy regime change may be due to the increased hydrodynamic drag of the surface material in our experiments, but may also support the notion that the quasi-static regime reduces as the effective gravity becomes lower.

  4. Numerical modeling of polyurea coated cementitious materials for flexure and impact loads

    Science.gov (United States)

    Pothula, Naga Deepika

    The research focuses on predicting the mechanical properties of various cementitious based materials coated with polyurea using the finite element program ABAQUS. To determine the effect of the polyurea coated systems, simple finite element analyses are performed on the beam model for flexure and the concrete slab model for impact. The experimental results carried out by Hyungjoo Choi [1, 2] are used to validate the model and to study the effect of the coating conditions of polyurea (plain, top, bottom, both). The load-displacement curves are plotted. Results show that using polyurea coating increases of deflection and load at failure (ductility), ultimate strength and strain, of Poly (Vinyl Butyral) (PVB) and Poly (Vinyl Alcohol) (PVA) fiber reinforced specimens. The simulation response for various models matched the experimental results very closely. Impact models depict the stresses developed and show that applying polyurea coating on the bottom seems to produce the best results.

  5. Guidelines for conducting impact tests on shipping packages for radioactive material

    Energy Technology Data Exchange (ETDEWEB)

    Mok, G.C.; Carlson, R.W.; Lu, S.C.; Fischer, L.E.

    1995-09-01

    Federal regulation (10 CFR Part 71) specifies a number of impact conditions (free-drop, penetration, and puncture), under which a package for the transport of radioactive materials must be tested or evaluated to demonstrate compliance with the regulation. This report is a comprehensive guide to the planning and execution of these impact tests. The report identifies the required considerations for both the design, pre-, and post-test inspections of the test model and the measurement, recording, analysis, and reporting of the test data. The report also presents reasons for the requirements, identifies the major difficulties in meeting these requirements, and suggests possible methods to overcome the difficulties. Discussed in substantial detail is the use of scale models and instrumented measurements.

  6. Fatigue Behavior of High Speed Steel Roll Materials for Hot Rolling by Laser Impacting

    Institute of Scientific and Technical Information of China (English)

    ZHOU Li; SUN Da-le; LIU Chang-sheng; WU Qiong

    2006-01-01

    The fatigue behavior of high speed steel (HSS) roll materials for hot rolling was researched under water-cooling conditions by laser impacting. The microstructure of HSS sample and the morphologies of fatigue samples were observed by scanning electron microscope. The phase structure was detected by XRD. The morphology of situ oxide scale was observed by optical microscope, and the expansion coefficient was measured by TGA. The experiment results indicate that the cracks come into being at the carbide-matrix interface, but there are no cracks in the matrix after many times of laser impacting treatment, for the situ sample taken from the fractured roll surface, big carbides are more sensitive to the fatigue, and peel off prior to small ones. The relevant fatigue mechanisms are also discussed.

  7. LIMITS OF SWOT ANALYSIS AND THEIR IMPACT ON DECISIONS IN EARLY WARNING SYSTEMS

    Directory of Open Access Journals (Sweden)

    Florin POPESCU

    2015-04-01

    Full Text Available SWOT (strengths, weaknesses, opportunities, threats analysis is useful in the decision-making process – crucial to any organization manager and/or strategist. This study aims to add value to the existing literature on SWOT, indicating its use and limitations, showing the need to link SWOT to other strategic tools and methodologies. As the current environment is turbulent and unpredictable, and economic cycles no longer comply with traditional rules, the precaution has become extremely important. That’s why SWOT should be supplemented with newer dynamic analysis capabilities and strategy tools, as early warning and opportunities system (EWOS, which can provide crucial inputs for scenario building, strategic thinking and decisions. EWOS is a novel approach based on three concepts that contribute to the ability of organization/project managers to develop outstanding capacity to "understand" and "benefit" in identifying opportunities and threats: (i business and competitive intelligence; (ii early warning thinking; (iii strategic thinking in decision making process. EWOS is of practical use for strategists and decision makers.

  8. Interviews with employed people with mobility impairments and limitations: environmental supports impacting work acquisition and satisfaction.

    Science.gov (United States)

    Miller, Lindsey C; Gottlieb, Meghan; Morgan, Kerri A; Gray, David B

    2014-01-01

    Less than 40% of people with disabilities work. Many studies have detailed the barriers to employment but few have examined the work experiences of those who are employed. A description of work conditions valued by a specific segment of employed people with disabilities is provided. Videotaped interviews of 33 successfully employed people with mobility impairments and limitations (PWMIL) were transcribed and analyzed to gather their perspectives on their work social and physical environments. Finding work was facilitated by family, friends and other social networks, vocational services, and prior education. Doing volunteer work, spending time at a paid and unpaid internship, and part-time work experiences were important aspects of job acquisition. Exterior and interior physical features were or had been made accessible. Expensive assistive technologies were paid for by the employee and their health insurance. Almost all personal assistance was provided by family, friends and co-workers. Work satisfaction included having a supportive employer, supportive co-workers, and flexible worksite policies. The interviews of employed PWMIL provide prospective employers and employees information on important social and physical work features that are needed to improve the possibilities for hiring people with disabilities and facilitating their successful careers.

  9. Transportation impact analysis for shipment of irradiated N-reactor fuel and associated materials

    Energy Technology Data Exchange (ETDEWEB)

    Daling, P.M.; Harris, M.S.

    1994-12-01

    An analysis of the radiological and nonradiological impacts of highway transportation of N-Reactor irradiated fuel (N-fuel) and associated materials is described in this report. N-fuel is proposed to be transported from its present locations in the 105-KE and 105-KW Basins, and possibly the PUREX Facility, to the 327 Building for characterization and testing. Each of these facilities is located on the Hanford Site, which is near Richland, Washington. The projected annual shipping quantity is 500 kgU/yr for 5 years for a total of 2500 kgU. It was assumed the irradiated fuel would be returned to the K- Basins following characterization, so the total amount of fuel shipped was assumed to be 5000 kgU. The shipping campaign may also include the transport and characterization of liquids, gases, and sludges from the storage basins, including fuel assembly and/or canister parts that may also be present in the basins. The impacts of transporting these other materials are bounded by the impacts of transporting 5000 kgU of N-fuel. This report was prepared to support an environmental assessment of the N-fuel characterization program. The RADTRAN 4 and GENII computer codes were used to evaluate the radiological impacts of the proposed shipping campaign. RADTRAN 4 was used to calculate the routine exposures and accident risks to workers and the general public from the N-fuel shipments. The GENII computer code was used to calculate the consequences of the maximum credible accident. The results indicate that the transportation of N-fuel in support of the characterization program should not cause excess radiological-induced latent cancer fatalities or traffic-related nonradiological accident fatalities. The consequences of the maximum credible accident are projected to be small and result in no excess latent cancer fatalities.

  10. Analysis of Multi-Layered Materials Under High Velocity Impact Using CTH

    Science.gov (United States)

    2008-03-01

    The momentum and energy integral equations are replaced by their explicit finite volume representations . While it is possible to solve these finite...was simulated and then compared with the results produced from the Lagrangian code ZeuS [55, 56]. Table 5.3: Johnson-Cook fracture coefficients for S7...was identified as the soft material. According to the results from the ZeuS code used by Zukas and Scheffler [56], for a impact velocity of 1164 m/s

  11. A comparative study of the impact properties of sandwich materials with different cores

    Directory of Open Access Journals (Sweden)

    Viot P.

    2012-08-01

    Full Text Available Sandwich panels are made of two high strength skins bonded to either side of a light weight core and are used in applications where high stiffness combined with low structural weight is required. The purpose of this paper is to compare the mechanical response of several sandwich panels whose core materials are different. Sandwich panels with glass fibre-reinforced polymer face sheets were used, combined with five different cores; polystyrene foam, polypropylene honeycomb, two different density Balsa wood and Cork. All specimens were subjected to low velocity impact and their structural response (Force-displacement curves were compared to quasistatic response of the panel tested using an hemispherical indenter.

  12. A comparative study of the impact properties of sandwich materials with different cores

    Science.gov (United States)

    Ramakrishnan, K. R.; Shankar, K.; Viot, P.; Guerard, S.

    2012-08-01

    Sandwich panels are made of two high strength skins bonded to either side of a light weight core and are used in applications where high stiffness combined with low structural weight is required. The purpose of this paper is to compare the mechanical response of several sandwich panels whose core materials are different. Sandwich panels with glass fibre-reinforced polymer face sheets were used, combined with five different cores; polystyrene foam, polypropylene honeycomb, two different density Balsa wood and Cork. All specimens were subjected to low velocity impact and their structural response (Force-displacement curves) were compared to quasistatic response of the panel tested using an hemispherical indenter.

  13. Photo catalytic self-cleaning materials: Principles and impact on atmosphere

    Directory of Open Access Journals (Sweden)

    Puzenat E.

    2009-02-01

    Full Text Available This chapter deals with self-cleaning materials which are one of the applications of photocatalysis. The ability of TiO2 to be activated under UV light allows one to perform oxidation reaction under sunlight. Consequently, since the middle of the ninety’s, many new products for outdoor applications, especially glasses, have been developed and commercialized. However, if photocatalytic principles are still true for them, some new mechanisms intervene and could modify chemical reaction implicated. At last, if the chemical reactions occurring at the surface of such products are well studied at laboratory scale, the researches for their impact on atmosphere only begin.

  14. The Impact of Authentic Materials and Tasks on Students’ Communicative Competence at a Colombian Language School

    Directory of Open Access Journals (Sweden)

    César Augusto Castillo Losada

    2017-01-01

    Full Text Available This article reports on a study carried out in a foreign language school at a Colombian public university. Its main purpose was to analyze the extent to which the use of authentic materials and tasks contributes to the enhancement of the communicative competence on an A2 level English course. A mixed study composed of a quasi-experimental and a descriptive-qualitative research design was implemented by means of a pre-test, a post-test, observations, semi-structured interviews, surveys, and diaries. The findings showed that the use of authentic materials and tasks, within the framework of a pedagogical project, had an impact on students’ communicative competence progress and on the teaching practices of the experimental group teacher.

  15. Validating material modelling for OFHC copper using dynamic tensile extrusion (DTE) test at different velocity impact

    Science.gov (United States)

    Bonora, N.; Testa, G.; Ruggiero, A.; Iannitti, G.; Colliander, M. Hörnquist; Mortazavi, N.

    2017-01-01

    In the Dynamic Tensile Extrusion (DTE) test, the material is subjected to very large strain, high strain rate and elevated temperature. Numerical simulation, validated comparing with measurements obtained on soft-recovered extruded fragments, can be used to probe material response under such extreme conditions and to assess constitutive models. In this work, the results of a parametric investigation on the simulation of DTE test of annealed OFHC copper - at impact velocity ranging from 350 up to 420 m/s - using the modified Rusinek-Klepaczko model, are presented. Simulation of microstructure evolution was performed using the visco-plastic self consistent model (VPSC), providing, as input, the velocity gradient history obtained with FEM at selected locations along the axis of the fragment trapped in the extrusion die. Finally, results are compared with EBSD analysis.

  16. Periprosthetic Infection following Primary Hip and Knee Arthroplasty: The Impact of Limiting the Postoperative Surveillance Period.

    Science.gov (United States)

    Roth, Virginia R; Mitchell, Robyn; Vachon, Julie; Alexandre, Stéphanie; Amaratunga, Kanchana; Smith, Stephanie; Vearncombe, Mary; Davis, Ian; Mertz, Dominik; Henderson, Elizabeth; John, Michael; Johnston, Lynn; Lemieux, Camille; Pelude, Linda; Gravel, Denise

    2017-02-01

    BACKGROUND Hip and knee arthroplasty infections are associated with considerable healthcare costs. The merits of reducing the postoperative surveillance period from 1 year to 90 days have been debated. OBJECTIVES To report the first pan-Canadian hip and knee periprosthetic joint infection (PJI) rates and to describe the implications of a shorter (90-day) postoperative surveillance period. METHODS Prospective surveillance for infection following hip and knee arthroplasty was conducted by hospitals participating in the Canadian Nosocomial Infection Surveillance Program (CNISP) using standard surveillance definitions. RESULTS Overall hip and knee PJI rates were 1.64 and 1.52 per 100 procedures, respectively. Deep incisional and organ-space hip and knee PJI rates were 0.96 and 0.71, respectively. In total, 93% of hip PJIs and 92% of knee PJIs were identified within 90 days, with a median time to detection of 21 days. However, 11%-16% of deep incisional and organ-space infections were not detected within 90 days. This rate was reduced to 3%-4% at 180 days post procedure. Anaerobic and polymicrobial infections had the shortest median time from procedure to detection (17 and 18 days, respectively) compared with infections due to other microorganisms, including Staphylococcus aureus. CONCLUSIONS PJI rates were similar to those reported elsewhere, although differences in national surveillance systems limit direct comparisons. Our results suggest that a postoperative surveillance period of 90 days will detect the majority of PJIs; however, up to 16% of deep incisional and organ-space infections may be missed. Extending the surveillance period to 180 days could allow for a better estimate of disease burden. Infect Control Hosp Epidemiol 2017;38:147-153.

  17. Limited Impact of a Fall-Seeded, Spring-Terminated Rye Cover Crop on Beneficial Arthropods.

    Science.gov (United States)

    Dunbar, Mike W; Gassmann, Aaron J; O'Neal, Matthew E

    2017-04-01

    Cover crops are beneficial to agroecosystems because they decrease soil erosion and nutrient loss while increasing within-field plant diversity. Greater plant diversity within cropping systems can positively affect beneficial arthropod communities. We hypothesized that increasing plant diversity within annually rotated corn and soybean with the addition of a rye cover crop would positively affect the beneficial ground and canopy-dwelling communities compared with rotated corn and soybean grown without a cover crop. From 2011 through 2013, arthropod communities were measured at two locations in Iowa four times throughout each growing season. Pitfall traps were used to sample ground-dwelling arthropods within the corn and soybean plots and sweep nets were used to measure the beneficial arthropods in soybean canopies. Beneficial arthropods captured were identified to either class, order, or family. In both corn and soybean, community composition and total community activity density and abundance did not differ between plots that included the rye cover crop and plots without the rye cover crop. Most taxa did not significantly respond to the presence of the rye cover crop when analyzed individually, with the exceptions of Carabidae and Gryllidae sampled from soybean pitfall traps. Activity density of Carabidae was significantly greater in soybean plots that included a rye cover crop, while activity density of Gryllidae was significantly reduced in plots with the rye cover crop. Although a rye cover crop may be agronomically beneficial, there may be only limited effects on beneficial arthropods when added within an annual rotation of corn and soybean. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Expected climate change impacts on extreme flows in Vietnam: The limits of bias correction techniques

    Science.gov (United States)

    Laux, Patrick; Dang, Thinh; Kunstmann, Harald

    2016-04-01

    We investigate possible impacts of climate change on future floods in the VuGia-ThuBon river basin, central Vietnam using a multi-model climate ensemble. An ensemble of regional climate projections (SRES) derived from different combinations of global and regional climate models in combination with different emission scenarios are used. In order to correct for the biases between the modelled climate variables and the observations, different bias correction techniques such as linear scaling, local intensity scaling, and quantile mapping are applied to the RCM outputs. Bias-corrected and raw climate data are then used as input for the fully distributed hydrological water balance model WaSIM-ETH to reproduce discharge data at NongSon station. Annual maximum discharges are extracted from the modeled daily series from the control period (1980-1999) and the future periods 2011-2030, 2031-2050, and 2080-2099 for subsequent extreme frequency analyses. To derive flood frequency curves for the four time periods, the generalized extreme value probability distribution is fitted to the data. Our analysis shows that actually none of the bias correction approaches applied to the control runs of simulated precipitation data can satisfactorily correct their distributions towards those of the observations. Therefore, this study builds further on the delta change approach, which adjusts the observed extreme values by the derived signals from the hydrological simulations fed by raw future climate projections. Adjusted return periods of e.g. HQ100 values are calculated based on the delta change method. The results inhibit a remarkable variation among the different climate scenarios in representing extreme values. Results show that MRI-MRI, ECHAM3-REMO, HadCMQ10-HadRM3P and HadCMQ13-HadRM3P models always exhibit a positive signal for all considered time slices and climate change scenarios. On the other hand, CCSM-MM5 frequently shows a negative signal for all time slices. On average, an

  19. Secondary materials: Engineering properties, environmental consequences, and social and economic impacts. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Breslin, V.; Reaven, S.; Schwartz, M.; Swanson, L.; Zweig, M.; Bortman, M.; Schubel, J.

    1993-08-01

    This report investigates two secondary materials, plastic lumber made from mixed plastic waste, and cement blocks and structures made with incinerator ash. Engineering properties, environmental impacts, and energy costs and savings of these secondary materials are compared to standard lumber products and cement blocks. Market capacity and social acceptance of plastic lumber and stabilized ash products are analyzed. These secondary materials apparently have potential markets; however, their economic value is primarily that they will not take up landfill space. For plastic lumber and stabilized incinerator ash products, marine and highway construction seem ideal public works applications. Incinerator ash may be suitable to use in seawalls, jetties, fishing reefs, highway barriers, and roadbed applications. Docks, piers, highway sound barriers, parking stops, and park furniture may all be made from plastic lumber. To encourage public acceptance and improve the market potential of secondary materials, these activities could be beneficial: industry should emphasize developing useful, long-lived products; industry and governments should create product performance criteria; government should provide rigorous testing and demonstration programs; and government and industry should cooperate to improve public outreach and educational programs.

  20. Environmental Impacts and Embodied Energy of Construction Methods and Materials in Low-Income Tropical Housing

    Directory of Open Access Journals (Sweden)

    Arman Hashemi

    2015-06-01

    Full Text Available This paper evaluates the current conditions of Ugandan low-income tropical housing with a focus on construction methods and materials in order to identify the key areas for improvement. Literature review, site visits and photographic surveys are carried out to collect relevant information on prevailing construction methods/materials and on their environmental impacts in rural areas. Low quality, high waste, and energy intensive production methods, as well as excessive soil extraction and deforestation, are identified as the main environmental damage of the current construction methods and materials. The embodied energy is highlighted as the key area which should be addressed to reduce the CO2 emissions of low-income tropical housing. The results indicate that the embodied energy of fired bricks in Uganda is up to 5.7 times more than general clay bricks. Concrete walling is identified as a much more environmentally friendly construction method compared to brick walling in East African countries. Improving fuel efficiency and moulding systems, increasing access to renewable energy sources, raising public awareness, educating local manufacturers and artisans, and gradual long-term introduction of innovative construction methods and materials which are adapted to local needs and conditions are some of the recommended actions to improve the current conditions.

  1. Environmental Impact Assessment of a School Building in Iceland Using LCA-Including the Effect of Long Distance Transport of Materials

    Directory of Open Access Journals (Sweden)

    Nargessadat Emami

    2016-11-01

    Full Text Available Buildings are the key components of urban areas and society as a complex system. A life cycle assessment was applied to estimate the environmental impacts of the resources applied in the building envelope, floor slabs, and interior walls of the Vættaskóli-Engi building in Reykjavik, Iceland. The scope of this study included four modules of extraction and transportation of raw material to the manufacturing site, production of the construction materials, and transport to the building site, as described in the standard EN 15804. The total environmental effects of the school building in terms of global warming potential, ozone depletion potential, human toxicity, acidification, and eutrophication were calculated. The total global warming potential impact was equal to 255 kg of CO2 eq/sqm, which was low compared to previous studies and was due to the limited system boundary of the current study. The effect of long-distance overseas transport of materials was noticeable in terms of acidification (25% and eutrophication (31% while it was negligible in other impact groups. The results also concluded that producing the cement in Iceland caused less environmental impact in all five impact categories compared to the case in which the cement was imported from Germany. The major contribution of this work is that the environmental impacts of different plans for domestic production or import of construction materials to Iceland can be precisely assessed in order to identify effective measures to move towards a sustainable built environment in Iceland, and also to provide consistent insights for stakeholders.

  2. Combined analysis of shock absorption capability and force dispersion effect of mouthguard materials with different impact objects.

    Science.gov (United States)

    Chowdhury, Ruman Uddin; Churei, Hiroshi; Takahashi, Hidekazu; Wada, Takahiro; Uo, Motohiro; Fukasawa, Shintaro; Abe, Keisuke; Shahrin, Sharika; Ueno, Toshiaki

    2014-01-01

    The aims of the present study were to investigate the shock absorption capability and force dispersion effect of mouthguard (MG) materials using load cell and film sensors. Two kinds of MG materials, ethylene vinyl acetate and polyolefin, were chosen for this study. When impact forces of approximately 5,000 N were applied on the MG materials using a round flat-nosed rod and a bluntly pointed rod, peak intensities were measured using the load cell sensor while peak stresses and impressed stress distribution areas were measured using the film sensor. Combined analysis using both load cell and film sensors clearly showed the shock absorption properties and force dispersion effects of different MG materials with different impact object shapes. Therefore, impact analysis involving a combined use of these sensor systems was useful and reliable in assessing the shock absorption capability and force dispersion effect of MG materials.

  3. Electronic voting in dental materials education: the impact on students' attitudes and exam performance.

    Science.gov (United States)

    Barbour, Michele E

    2008-09-01

    Dental materials is an integral part of any undergraduate dental curriculum and is most commonly taught in a traditional didactic, lecture-based format. It suffers from the ignominy of being viewed by many as a dry, factual subject with little to excite or engage the student. In this article, the author presents the experimental use of an electronic voting (eVoting) system in an undergraduate dental materials course. The practical and aspirational aspects of its application are described. The objective was to assess the student perception of the experiment and the impact on end-of-course examination results. The eVoting system proved overwhelmingly popular with the students with 95 percent in favor of its use at the beginning of the course and 91 percent at the end. There was, however, no statistically significant impact on the results of the examination at the end of the course, when compared to the previous year's cohort of students for whom eVoting was not used. eVoting encouraged student interaction and engagement and contributed to student satisfaction but was not seen to affect the outcome measurement (end-of-course examination result).

  4. Semi-Supervised Bayesian Classification of Materials with Impact-Echo Signals

    Directory of Open Access Journals (Sweden)

    Jorge Igual

    2015-05-01

    Full Text Available The detection and identification of internal defects in a material require the use of some technology that translates the hidden interior damages into observable signals with different signature-defect correspondences. We apply impact-echo techniques for this purpose. The materials are classified according to their defective status (homogeneous, one defect or multiple defects and kind of defect (hole or crack, passing through or not. Every specimen is impacted by a hammer, and the spectrum of the propagated wave is recorded. This spectrum is the input data to a Bayesian classifier that is based on the modeling of the conditional probabilities with a mixture of Gaussians. The parameters of the Gaussian mixtures and the class probabilities are estimated using an extended expectation-maximization algorithm. The advantage of our proposal is that it is flexible, since it obtains good results for a wide range of models even under little supervision; e.g., it obtains a harmonic average of precision and recall value of 92.38% given only a 10% supervision ratio. We test the method with real specimens made of aluminum alloy. The results show that the algorithm works very well. This technique could be applied in many industrial problems, such as the optimization of the marble cutting process.

  5. Semi-supervised Bayesian classification of materials with impact-echo signals.

    Science.gov (United States)

    Igual, Jorge; Salazar, Addisson; Safont, Gonzalo; Vergara, Luis

    2015-05-19

    The detection and identification of internal defects in a material require the use of some technology that translates the hidden interior damages into observable signals with different signature-defect correspondences. We apply impact-echo techniques for this purpose. The materials are classified according to their defective status (homogeneous, one defect or multiple defects) and kind of defect (hole or crack, passing through or not). Every specimen is impacted by a hammer, and the spectrum of the propagated wave is recorded. This spectrum is the input data to a Bayesian classifier that is based on the modeling of the conditional probabilities with a mixture of Gaussians. The parameters of the Gaussian mixtures and the class probabilities are estimated using an extended expectation-maximization algorithm. The advantage of our proposal is that it is flexible, since it obtains good results for a wide range of models even under little supervision; e.g., it obtains a harmonic average of precision and recall value of 92.38% given only a 10% supervision ratio. We test the method with real specimens made of aluminum alloy. The results show that the algorithm works very well. This technique could be applied in many industrial problems, such as the optimization of the marble cutting process.

  6. The CERN antiproton target: hydrocode analysis of its core material dynamic response under proton beam impact

    CERN Document Server

    Martin, Claudio Torregrosa; Calviani, Marco; Muñoz-Cobo, José-Luis

    2016-01-01

    Antiprotons are produced at CERN by colliding a 26 GeV/c proton beam with a fixed target made of a 3 mm diameter, 55 mm length iridium core. The inherent characteristics of antiproton production involve extremely high energy depositions inside the target when impacted by each primary proton beam, making it one of the most dynamically demanding among high energy solid targets in the world, with a rise temperature above 2000 {\\deg}C after each pulse impact and successive dynamic pressure waves of the order of GPa's. An optimized redesign of the current target is foreseen for the next 20 years of operation. As a first step in the design procedure, this numerical study delves into the fundamental phenomena present in the target material core under proton pulse impact and subsequent pressure wave propagation by the use of hydrocodes. Three major phenomena have been identified, (i) the dominance of a high frequency radial wave which produces destructive compressive-to-tensile pressure response (ii) The existence of...

  7. Use of elemental materials for the creation of an in-situ space dust impacts detector

    Science.gov (United States)

    Faure, P.; Matsumoto, S.; Akahoshi, Y.; Cho, M.; Narumi, T.; Kitazawa, Y.; Sakurai, A.; Koura, T.

    2012-02-01

    This research focuses on space dust ranging from 100μm to 1mm. Space dust is mainly due to secondary space debris, which is called ejecta. The objective was to create an inexpensive space dust impacts detector using elemental materials. The detector is a glass/epoxy laminate printed circuit board with an area of 81cm2 for a weight of 30g. The detector can estimate the number of impacts and can give an approximation of the space dust size. The detector will be mounted on Horyu II that will operate in polar orbit for one year. In this article the authors report: a) the production of ejecta, b) the ejecta experiments on solar array coupon, aluminium honeycomb and CFRP/aluminium honeycomb, c) the detector's working principle and d) the estimations of the minimum detectable size of debris and collision probability. The ejecta experiments demonstrated that the ejecta's mass is 7 to 46 times higher than the projectile's mass. For space dust in the range 100μm - 600μm in diameter, the collision probability was calculated to be 16.5 percent. The detector's capabilities to detect broken lines and to transmit the data to the on-board computer were also demonstrated. This in-situ space dust impacts detector is thus a very promising research area for its lightness, low cost and its ability to provide immediate data on space dust population.

  8. CERN antiproton target: Hydrocode analysis of its core material dynamic response under proton beam impact

    Science.gov (United States)

    Martin, Claudio Torregrosa; Perillo-Marcone, Antonio; Calviani, Marco; Muñoz-Cobo, José-Luis

    2016-07-01

    Antiprotons are produced at CERN by colliding a 26 GeV /c proton beam with a fixed target made of a 3 mm diameter, 55 mm length iridium core. The inherent characteristics of antiproton production involve extremely high energy depositions inside the target when impacted by each primary proton beam, making it one of the most dynamically demanding among high energy solid targets in the world, with a rise temperature above 2000 °C after each pulse impact and successive dynamic pressure waves of the order of GPa's. An optimized redesign of the current target is foreseen for the next 20 years of operation. As a first step in the design procedure, this numerical study delves into the fundamental phenomena present in the target material core under proton pulse impact and subsequent pressure wave propagation by the use of hydrocodes. Three major phenomena have been identified, (i) the dominance of a high frequency radial wave which produces destructive compressive-to-tensile pressure response (ii) The existence of end-of-pulse tensile waves and its relevance on the overall response (iii) A reduction of 44% in tensile pressure could be obtained by the use of a high density tantalum cladding.

  9. Quantitative impact characterization of aeronautical CFRP materials with non-destructive testing methods

    Science.gov (United States)

    Kiefel, Denis; Stoessel, Rainer; Grosse, Christian

    2015-03-01

    In recent years, an increasing number of safety-relevant structures are designed and manufactured from carbon fiber reinforced polymers (CFRP) in order to reduce weight of airplanes by taking the advantage of their specific strength into account. Non-destructive testing (NDT) methods for quantitative defect analysis of damages are liquid- or air-coupled ultrasonic testing (UT), phased array ultrasonic techniques, and active thermography (IR). The advantage of these testing methods is the applicability on large areas. However, their quantitative information is often limited on impact localization and size. In addition to these techniques, Airbus Group Innovations operates a micro x-ray computed tomography (μ-XCT) system, which was developed for CFRP characterization. It is an open system which allows different kinds of acquisition, reconstruction, and data evaluation. One main advantage of this μ-XCT system is its high resolution with 3-dimensional analysis and visualization opportunities, which enables to gain important quantitative information for composite part design and stress analysis. Within this study, different NDT methods will be compared at CFRP samples with specified artificial impact damages. The results can be used to select the most suitable NDT-method for specific application cases. Furthermore, novel evaluation and visualization methods for impact analyzes are developed and will be presented.

  10. Quantitative impact characterization of aeronautical CFRP materials with non-destructive testing methods

    Energy Technology Data Exchange (ETDEWEB)

    Kiefel, Denis, E-mail: Denis.Kiefel@airbus.com, E-mail: Rainer.Stoessel@airbus.com; Stoessel, Rainer, E-mail: Denis.Kiefel@airbus.com, E-mail: Rainer.Stoessel@airbus.com [Airbus Group Innovations, Munich (Germany); Grosse, Christian, E-mail: Grosse@tum.de [Technical University Munich (Germany)

    2015-03-31

    In recent years, an increasing number of safety-relevant structures are designed and manufactured from carbon fiber reinforced polymers (CFRP) in order to reduce weight of airplanes by taking the advantage of their specific strength into account. Non-destructive testing (NDT) methods for quantitative defect analysis of damages are liquid- or air-coupled ultrasonic testing (UT), phased array ultrasonic techniques, and active thermography (IR). The advantage of these testing methods is the applicability on large areas. However, their quantitative information is often limited on impact localization and size. In addition to these techniques, Airbus Group Innovations operates a micro x-ray computed tomography (μ-XCT) system, which was developed for CFRP characterization. It is an open system which allows different kinds of acquisition, reconstruction, and data evaluation. One main advantage of this μ-XCT system is its high resolution with 3-dimensional analysis and visualization opportunities, which enables to gain important quantitative information for composite part design and stress analysis. Within this study, different NDT methods will be compared at CFRP samples with specified artificial impact damages. The results can be used to select the most suitable NDT-method for specific application cases. Furthermore, novel evaluation and visualization methods for impact analyzes are developed and will be presented.

  11. Bibliography of documents and related materials collected for the Hawaii Geothermal Project Environmental Impact Statement

    Energy Technology Data Exchange (ETDEWEB)

    Glenn, F.M.; Boston, C.R.; Burns, J.C.; Hagan, C.W. Jr.; Saulsbury, J.W.; Wolfe, A.K.

    1995-03-01

    This report has been prepared to make available and archive information developed during preparation of the Environmental Impact Statement for Phases 3 and 4 of the Hawaii Geothermal Project as defined by the state of Hawaii in its April 1989 proposal to Congress. On May 17, 1994, the USDOE published a notice in the Federal Register withdrawing its Notice of Intent of February 14, 1992, to prepare the HGP EIS. Since the state of Hawaii is no longer pursuing or planning to pursue the HGP, DOE considers the project to be terminated. This report provides a bibliography of documents, published papers, and other reference materials that were obtained or used. The report provides citations for approximately 642 documents, published papers, and other reference materials that were gathered to describe the potentially affected environment on the islands of Hawaii, Maui, and Oahu. The listing also does not include all the reference materials developed by support subcontractors and cooperating agencies who participated in the project. This listing does not include correspondence or other types of personal communications. The documents listed in this report can be obtained from original sources or libraries.

  12. Impact of Waste Materials and Organic Amendments on Soil Properties and Vegetative Performance

    Directory of Open Access Journals (Sweden)

    Steven L. McGeehan

    2012-01-01

    Full Text Available Waste materials, and materials derived from wastes, possess many characteristics that can improve soil fertility and enhance crop performance. These materials can be particularly useful as amendments to severely degraded soils associated with mining activities. This study evaluated biosolids, composts, log yard wastes, and two organic soil treatments for improved soil fertility and vegetative performance using side-by-side comparisons. Each plot was seeded with a standardized seed mix and evaluated for a series of soil chemical and physical parameters, total vegetation response, species diversity, ecological plant response, and invasion indices. All treatments were successful at improving soil fertility and promoting a self-sustaining vegetative cover. The level of available nitrogen had a strong impact on vegetative coverage, species distribution, and extent of unseeded vegetation. For example, high nitrogen treatments promoted a grass-dominated (low forb plant community with a low content of unseeded vegetation. In contrast, low nitrogen treatments promoted a more balanced plant community with a mixture of grass and forb species and greater susceptibility to unseeded vegetation establishment.

  13. Impact of microcrystalline cellulose material attributes: a case study on continuous twin screw granulation.

    Science.gov (United States)

    Fonteyne, Margot; Correia, Ana; De Plecker, Sofie; Vercruysse, Jurgen; Ilić, Ilija; Zhou, Qi; Vervaet, Chris; Remon, Jean Paul; Onofre, Fernanda; Bulone, Vincent; De Beer, Thomas

    2015-01-30

    The International Conference on Harmonisation (ICH) states in its Q8 'Pharmaceutical Development' guideline that the manufacturer of pharmaceuticals should have an enhanced knowledge of the product performance over a range of material attributes, manufacturing process options and process parameters. The present case study evaluates the effect of unspecified variability of raw material properties upon the quality attributes of granules; produced using a continuous from-powder-to-tablet wet granulation line (ConsiGma™ 25). The impact of different material attributes of six samples of microcrystalline cellulose (MCC) was investigated. During a blind study the different samples of MCC were used separately and the resulting granules were evaluated in order to identify the differences between the six samples. Variation in size distribution due to varying water binding capacity of the MCC samples was observed. The cause of this different water binding capacity was investigated and was caused by a different degree of crystallinity. Afterwards, an experimental design was conducted in order to evaluate the effect of both product and process variability upon the granule size distribution. This model was used in order to calculate the required process parameters to obtain a preset granule size distribution regardless of the type of MCC used. The difference in water binding capacity and its effect on granular properties was still present when combining the MCC grades with different binders. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Influence of the Integration Limits on the Shape of Pair Correlation Functions of Non-Crystalline Materials

    Science.gov (United States)

    2001-06-01

    Correlation Functions of Non- Crystalline Materials DISTRIBUTION: Approved for public release, distribution unlimited This paper is part of the...PAIR CORRELATION FUNCTIONS OF NON- CRYSTALLINE MATERIALS W. Hoyer, I. Kaban, Th. Halm Institute of Physics, TU - Chemnitz, D-09107, Chemnitz, Germany...correlation functions of the non- crystalline materials with low-coordinated (open) structure. Liquid Te and amorphous Ge-telluride have been chosen for

  15. Habitat selection and risk of predation: re-colonization by lynx had limited impact on habitat selection by roe deer.

    Directory of Open Access Journals (Sweden)

    Gustaf Samelius

    Full Text Available Risk of predation is an evolutionary force that affects behaviors of virtually all animals. In this study, we examined how habitat selection by roe deer was affected by risk of predation by Eurasian lynx - the main predator of roe deer in Scandinavia. Specifically, we compared how habitat selection by roe deer varied (1 before and after lynx re-established in the study area and (2 in relation to habitat-specific risk of predation by lynx. All analyses were conducted at the spatial and temporal scales of home ranges and seasons. We did not find any evidence that roe deer avoided habitats in which the risk of predation by lynx was greatest and information-theoretic model selection showed that re-colonization by lynx had limited impact on habitat selection by roe deer despite lynx predation causing 65% of known mortalities after lynx re-colonized the area. Instead we found that habitat selection decreased when habitat availability increased for 2 of 5 habitat types (a pattern referred to as functional response in habitat selection. Limited impact of re-colonization by lynx on habitat selection by roe deer in this study differs from elk in North America altering both daily and seasonal patterns in habitat selection at the spatial scales of habitat patches and home ranges when wolves were reintroduced to Yellowstone National Park. Our study thus provides further evidence of the complexity by which animals respond to risk of predation and suggest that it may vary between ecosystems and predator-prey constellations.

  16. Reporting surgical site infections following total hip and knee arthroplasty: impact of limiting surveillance to the operative hospital.

    Science.gov (United States)

    Yokoe, Deborah S; Avery, Taliser R; Platt, Richard; Huang, Susan S

    2013-11-01

    Public reporting of surgical site infections (SSIs) by hospitals is largely limited to infections detected during surgical hospitalizations or readmissions to the same facility. SSI rates may be underestimated if patients with SSIs are readmitted to other hospitals. We assessed the impact of readmissions to other facilities on hospitals' SSI rates following primary total hip arthroplasty (THA) or total knee arthroplasty (TKA). This was a retrospective cohort study of all patients who underwent primary THA or TKA at California hospitals between 1 January 2006 and 31 December 2009. SSIs were identified using ICD-9-CM diagnosis codes predictive of SSI assigned at any California hospital within 365 days of surgery using a statewide repository of hospital data that allowed tracking of patients between facilities. We used statewide data to estimate the fraction of each hospital's THA and TKA SSIs identified at the operative hospital versus other hospitals. A total of 91 121 THA and 121 640 TKA procedures were identified. Based on diagnosis codes, SSIs developed following 2214 (2.3%) THAs and 2465 (2.0%) TKAs. Seventeen percent of SSIs would have been missed by operative hospital surveillance alone. The proportion of hospitals' SSIs detected at nonoperative hospitals ranged from 0% to 100%. Including SSIs detected at nonoperative hospitals resulted in better relative ranking for 61% of THA hospitals and 61% of TKA hospitals. Limiting SSI surveillance to the operative hospital caused varying degrees of SSI underestimation and substantially impacted hospitals' relative rankings, suggesting that alternative methods for comprehensive postdischarge surveillance are needed for accurate benchmarking.

  17. Hazardous Materials Verification and Limited Characterization Report on Sodium and Caustic Residuals in Materials and Fuel Complex Facilities MFC-799/799A

    Energy Technology Data Exchange (ETDEWEB)

    Gary Mecham

    2010-08-01

    This report is a companion to the Facilities Condition and Hazard Assessment for Materials and Fuel Complex Sodium Processing Facilities MFC-799/799A and Nuclear Calibration Laboratory MFC-770C (referred to as the Facilities Condition and Hazards Assessment). This report specifically responds to the requirement of Section 9.2, Item 6, of the Facilities Condition and Hazards Assessment to provide an updated assessment and verification of the residual hazardous materials remaining in the Sodium Processing Facilities processing system. The hazardous materials of concern are sodium and sodium hydroxide (caustic). The information supplied in this report supports the end-point objectives identified in the Transition Plan for Multiple Facilities at the Materials and Fuels Complex, Advanced Test Reactor, Central Facilities Area, and Power Burst Facility, as well as the deactivation and decommissioning critical decision milestone 1, as specified in U.S. Department of Energy Guide 413.3-8, “Environmental Management Cleanup Projects.” Using a tailored approach and based on information obtained through a combination of process knowledge, emergency management hazardous assessment documentation, and visual inspection, this report provides sufficient detail regarding the quantity of hazardous materials for the purposes of facility transfer; it also provides that further characterization/verification of these materials is unnecessary.

  18. Hard-sphere limit of soft-sphere model for granular materials: Stiffness dependence of steady granular flow

    OpenAIRE

    Mitarai, Namiko; Nakanishi, Hiizu

    2002-01-01

    Dynamical behavior of steady granular flow is investigated numerically in the inelastic hard sphere limit of the soft sphere model. We find distinctively different limiting behaviors for the two flow regimes, i.e., the collisional flow and the frictional flow. In the collisional flow, the hard sphere limit is straightforward; the number of collisions per particle per unit time converges to a finite value and the total contact time fraction with other particles goes to zero. For the frictional...

  19. Evaluation of impact limiter performance during end-on and slapdown drop tests of a one-third scale model storage/transport cask system

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimura, H.R.; Bronowski, D.R.; Uncapher, W.L.; Attaway, S.W.; Bateman, V.I.; Carne, T.G.; Gregory, D.L. (Sandia National Labs., Albuquerque, NM (USA)); Huerta, M. (Southwest Engineering Associates, El Paso, TX (USA))

    1990-12-01

    This report describes drop testing of a one-third scale model shipping cask system. Two casks were designed and fabricated by Transnuclear, Inc., to ship spent fuel from the former Nuclear Fuel Services West Valley reprocessing facility in New York to the Idaho National Engineering Laboratory for a long-term spent fuel dry storage demonstration project. As part of the NRC's regulatory certification process, one-third scale model tests were performed to obtain experimental data on impact limiter performance during impact testing. The objectives of the testing program were to (1) obtain deceleration and displacement information for the cask and impact limiter system, (2) obtain dynamic force-displacement data for the impact limiters, (3) verify the integrity of the impact limiter retention system, and (4) examine the crush behavior of the limiters. Two 30-ft (9-m) drop tests were conducted on a mass model of the cask body and scaled balsa and redwood-filled impact limiters. This report describes the results of both tests in terms of measured decelerations, posttest deformation measurements, and the general structural response of the system. 3 refs., 32 figs.

  20. Evaluation of Dynamic Deformation Behaviors in Metallic Materials under High Strain-Rates Using Taylor Bar Impact Test

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Kyung Oh; Shin, Hyung Seop [Andong National Univ., Andong (Korea, Republic of)

    2016-09-15

    To ensure the reliability and safety of various mechanical systems in accordance with their high-speed usage, it is necessary to evaluate the dynamic deformation behavior of structural materials under impact load. However, it is not easy to understand the dynamic deformation behavior of the structural materials using experimental methods in the high strain-rate range exceeding 10{sup 4} s{sup -1}. In this study, the Taylor bar impact test was conducted to investigate the dynamic deformation behavior of metallic materials in the high strain-rate region, using a high-speed photography system. Numerical analysis of the Taylor bar impact test was performed using AUTODYN S/W. The results of the analysis were compared with the experimental results, and the material behavior in the high strain-rate region was discussed.

  1. Evaluating opportunities to improve material and energy impacts in commodity supply chains

    Energy Technology Data Exchange (ETDEWEB)

    Hanes, Rebecca J.; Carpenter, Alberta

    2017-01-10

    When evaluated at the scale of individual processes, next-generation technologies may be more energy and emissions intensive than current technology. However, many advanced technologies have the potential to reduce material and energy consumption in upstream or downstream processing stages. In order to fully understand the benefits and consequences of technology deployment, next-generation technologies should be evaluated in context, as part of a supply chain. This work presents the Materials Flow through Industry (MFI) supply chain modeling tool. The MFI tool is a cradle-to-gate linear network model of the US industrial sector that can model a wide range of manufacturing scenarios, including changes in production technology and increases in industrial energy efficiency. The MFI tool was developed to perform supply chain scale analyses in order to quantify the impacts and benefits of next-generation technologies and materials at that scale. For the analysis presented in this paper, the MFI tool is utilized to explore a case study comparing three lightweight vehicle supply chains to the supply chain of a conventional, standard weight vehicle. Several of the lightweight vehicle supply chains are evaluated under manufacturing scenarios that include next-generation production technologies and next-generation materials. Results indicate that producing lightweight vehicles is more energy and emission intensive than producing the non-lightweight vehicle, but the fuel saved during vehicle use offsets this increase. In this case study, greater reductions in supply chain energy and emissions were achieved through the application of the next-generation technologies than from application of energy efficiency increases.

  2. Scaling impact and shock-compression response for porous materials: Application to planetary formation

    Science.gov (United States)

    Jeanloz, R.

    2016-12-01

    A thermodynamic model based on the Mie-Grüneisen equation of state does a good job of describing the response of porous materials to impact, so can provide insights into the accretion and cohesion of planetesimals too small to be significantly held together by gravity (e.g., tens of km or less in average diameter). The model identifies an offset in Hugoniot pressure (∆PH) due to porosity that is found to be in agreement with experimental shock-compression measurements for samples having a wide range of initial porosities. Assuming the Grüneisen parameter (γ) is proportional to volume (γ/V = constant), the relative offset in Hugoniot pressure as a function of initial porosity (φ = 1 - V0/V0por) and compression (η = 1 - V/V0) is ∆PH/PH = γ0 φ/[2(1 - φ) - γ0 (φ + η(1 - φ))] where subscripts 0 and por represent zero-pressure (non-porous) conditions and a porous sample, respectively. This additional thermal pressure at a given volume is due to the extra internal energy and corresponding temperature increase associated with collapsing pores (Fig. 1: near-identical curves for φ = 0.001 and 0.01). This result can be interpreted as indicating that upon collapse individual pores create hot spots with temperatures of order 103-104K above the background, suggesting that impact into an initially porous target can result in cohesion due to partial melting and vaporization. Moreover, the waste heat associated with pore closure far exceeds the dissipation in shock loading of non-porous material, reflecting the ability of a porous target to absorb and dissipate impact energy. The Mie-Grüneisen model along with analysis of waste heat thus provides a scaling for planetesimal impact that might explain how rock and regolith accrete into a gravitationally bound planet. Fig. 1. Porosity-induced anomaly in Hugoniot temperature per unit of porosity, shown as a function of compression for samples with initial porosity φ = 0.001 (green), 0.01 (blue) and 0.1 (gold

  3. Impact of sampling time deviations on the prediction of the area under the curve using regression limited sampling strategies.

    Science.gov (United States)

    Sarem, Sarem; Nekka, Fahima; Ahmed, Iman Saad; Litalien, Catherine; Li, Jun

    2015-10-01

    The regression limited sampling strategy approach (R-LSS), which is based on a small number of blood samples drawn at selected time points, has been used as an alternative method for the estimation of the area under the concentration-time curve (AUC). However, deviations from planned sampling times may affect the performance of R-LSS, influencing related therapeutic decisions and outcomes. The aim of this study was to investigate the impact of different sampling time deviation (STD) scenarios on the estimation of AUC by the R-LSS using a simulation approach. Three types of scenarios were considered going from the simplest case of fixed deviations, to random deviations and then to a more realistic case where deviations of mixed nature can occur. In addition, the sensitivity of the R-LSS to STD in each involved sampling point was evaluated. A significant impact of STD on the performance of R-LSS was demonstrated. The tolerance of R-LSS to STD was found to depend not only on the number of sampling points but more importantly on the duration of the sampling process. Sensitivity analysis showed that sampling points at which rapid concentration changes occur were relatively more critical for AUC prediction by R-LSS. As a practical approach, nomograms were proposed, where the expected predictive performance of R-LSS was provided as a function of STD information. The investigation of STD impact on the predictive performance of R-LSS is a critical element and should be routinely performed to guide R-LSS selection and use.

  4. Health Economics as Rhetoric: The Limited Impact of Health Economics on Funding Decisions in Four European Countries.

    Science.gov (United States)

    Franken, Margreet; Heintz, Emelie; Gerber-Grote, Andreas; Raftery, James

    2016-12-01

    A response to the challenge of high-cost treatments in health care has been economic evaluation. Cost-effectiveness analysis presented as cost per quality-adjusted life-years gained has been controversial, raising heated support and opposition. To assess the impact of economic evaluation in decisions on what to fund in four European countries and discuss the implications of our findings. We used a protocol to review the key features of the application of economic evaluation in reimbursement decision making in England, Germany, the Netherlands, and Sweden, reporting country-specific highlights. Although the institutions and processes vary by country, health economic evaluation has had limited impact on restricting access of controversial high-cost drugs. Even in those countries that have gone the furthest, ways have been found to avoid refusing to fund high-cost drugs for particular diseases including cancer, multiple sclerosis, and orphan diseases. Economic evaluation may, however, have helped some countries to negotiate price reductions for some drugs. It has also extended to the discussion of clinical effectiveness to include cost. The differences in approaches but similarities in outcomes suggest that health economic evaluation be viewed largely as rhetoric (in D.N. McCloskey's terms in The Rhetoric of Economics, 1985). This is not to imply that economics had no impact: rather that it usually contributed to the discourse in ways that differed by country. The reasons for this no doubt vary by perspective, from political science to ethics. Economic evaluation may have less to do with rationing or denial of medical treatments than to do with expanding the discourse used to discuss such issues. Copyright © 2016 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  5. The Impact of Religiosity on Peer Communication, the Traditional Media, and Materialism among Young Adult Consumers

    Directory of Open Access Journals (Sweden)

    Eric V. Bindah

    2012-10-01

    Full Text Available The main objectives of this study are to compare the differences between the various religious groups and peer communication, the traditional media and materialism among young adult consumers in Malaysia. This paper briefly conceptualizes the role of peer communication, and the traditional media in the development of values based on existing literature. Next, a brief review of literature is made to illustrate the association between religiosity and materialism. This study takes place in Malaysia, a country in the Southeast Asia embracing a multi-ethnic and multi-cultural society. Preliminary statistical procedures were employed to examine possible significant group differences in peer communication, traditional media and materialism based on various major beliefs system endorsed by Malaysians. A one-way analysis of variance was utilised to determine the significant differences in terms of religion with respect to their responses on the various measures. When there were significant differences, Post Hoc Tests (Scheffe were used to determine the particular groups which differed significantly within a significant overall one-way analysis of variance. The implications, significance and limitations of the study are discussed as a concluding remark.

  6. Estimating the Lower Limit of the Impact of Amines on Nucleation in the Earth’s Atmosphere

    Directory of Open Access Journals (Sweden)

    Alexey B. Nadykto

    2015-04-01

    Full Text Available Amines, organic derivatives of NH3, are important common trace atmospheric species that can enhance new particle formation in the Earth’s atmosphere under favorable conditions. While methylamine (MA, dimethylamine (DMA and trimethylamine (TMA all efficiently enhance binary nucleation, MA may represent the lower limit of the enhancing effect of amines on atmospheric nucleation. In the present paper, we report new thermochemical data concerning MA-enhanced nucleation, which were obtained using the DFT PW91PW91/6-311++G (3df, 3pd method, and investigate the enhancement in production of stable pre-nucleation clusters due to the MA. We found that the MA ternary nucleation begins to dominate over ternary nucleation of sulfuric acid, water and ammonia at [MA]/[NH3] > ~10−3. This means that under real atmospheric conditions ([MA] ~ 1 ppt, [NH3] ~ 1 ppb the lower limit of the enhancement due to methylamines is either close to or higher than the typical effect of NH3. A very strong impact of the MA is observed at low RH; however it decreases quickly as the RH grows. Low RH and low ambient temperatures were found to be particularly favorable for the enhancement in production of stable sulfuric acid-water clusters due to the MA.

  7. Impact of the 0.1% fuel sulfur content limit in SECA on particle and gaseous emissions from marine vessels

    Science.gov (United States)

    Zetterdahl, Maria; Moldanová, Jana; Pei, Xiangyu; Pathak, Ravi Kant; Demirdjian, Benjamin

    2016-11-01

    Emissions were measured on-board a ship in the Baltic Sea, which is a sulfur emission control area (SECA), before and after the implementation of the strict fuel sulfur content (FSC) limit of 0.1 m/m% S on the 1st of January 2015. Prior to January 2015, the ship used a heavy fuel oil (HFO) but switched to a low-sulfur residual marine fuel oil (RMB30) after the implementation of the new FSC limit. The emitted particulate matter (PM) was measured in terms of mass, number, size distribution, volatility, elemental composition, content of organics, black and elemental carbon, polycyclic aromatic hydrocarbons (PAHs), microstructure and micro-composition, along with the gaseous emissions at different operating conditions. The fuel change reduced emissions of PM mass up to 67%. The number of particles emitted remained unchanged and were dominated by nanoparticles. Furthermore, the fuel change resulted in an 80% reduction of SO2 emissions and decreased emissions of total volatile organic compounds (VOCs). The emissions of both monoaromatic and lighter polyaromatic hydrocarbon compounds increased with RMB30, while the heavy, PM-bound PAH species that belong to the carcinogenic PAH family were reduced. Emissions of BC remained similar between the two fuels. This study indicates that the use of low-sulfur residual marine fuel oil is a way to comply with the new FSC regulation and will reduce the anthropogenic load of SO2 emissions and secondary PM formed from SO2. Emissions of primary particles, however, remain unchanged and do not decrease as much as would be expected if distilled fuel was used. This applies both to the number of particles emitted and some toxic components, such as heavy metals, PAHs or elemental carbon (EC). The micro-composition analyses showed that the soot particles emitted from RMB30 combustion often do not have any trace of sulfur compared with particles from HFO combustion, which always have a sulfur content over 1%m/m. The soot sulfur content can

  8. Temperature impact on cementitious materials carbonation - description of water transport influence; Impact de la temperature sur la carbonatation des materiaux cimentaires -prise en compte des transferts hydriques

    Energy Technology Data Exchange (ETDEWEB)

    Drouet, E.

    2010-11-15

    evolution (porosity coarsening). The environmental conditions impact is studied using preconditioned samples (12 different RHs and 20, 50 and 80 C) and accelerated carbonation tests. The latter are performed in a new device allowing accurate control of the environmental conditions as well as the carbon dioxide concentration. The carbonated depths and the mineralogical modifications induced by carbonation are assessed using XRD and TGA for each temperature and RH. Most of the mineralogical modifications notified in temperature (hydrates consumption and nature of crystallographic phase of calcium carbonate) are similar with these identified at ambient temperature. Yet the results show a significant influence of the environmental conditions on calcium carbonate polymorphic abundance: the lower the RH, the more abundant the metastable phases (vaterite and aragonite). The rate of the polymorphic transformation (from the metastable states into calcite by dissolution precipitation) is believed to decrease with RH because of lack of liquid water. A significant influence of the environmental conditions on the carbonation rate is also observed. It depends of the competition between the temperature effect on moisture transfer and retrograde solubility of reactants. Carbonation depths appear to be maximal at the RH-starting point of capillary condensation of each material and temperature. Carbonation depths increase with temperature until a limit of temperature characteristic of the material. Above this temperature, reactants solubility might control the main process. (author)

  9. Wave Shaping and Lateral Spreading of Impact Loads Using Layered Materials and Structures

    Science.gov (United States)

    Ding, J. L.; Robbins, J.; Gupta, Y. M.; Wong, M. K.

    1999-06-01

    The overall objective of our work is to explore a new concept for developing resilient armor using high wave speed layers to rapidly spread the loads arising from projectile impacts. Because layered structures involve many additional geometrical and material variables, and because layers affect stress distribution and energy absorption capability of the target, a fundamental issue in determining layering effects is the quantification of load spreading in a consistent manner. We have found that the distribution of dissipative energy density normalized by the averaged total energy density imparted to the substrate appears to be an effective measure for evaluating load spreading and penetration resistance of layered targets. Using this measure in numerical simulations, we have demonstrated the feasibility of the load spreading concept. In addition, we have also investigated numerically the effects of layering geometry, and mechanical properties of the layer and substrate on load spreading. Experimental work is currently underway to evaluate the computational results.

  10. Impact of intrinsic localized modes of atomic motion on materials properties

    Energy Technology Data Exchange (ETDEWEB)

    Manley, M E

    2010-01-20

    Recent neutron and x-ray scattering measurements show intrinsic localized modes (ILMs) in metallic uranium and ionic sodium iodide. Here, the role ILMs play in the behavior of these materials is examined. With the thermal activation of ILMs, thermal expansion is enhanced, made more anisotropic, and, at a microscopic level, becomes inhomogeneous. Interstitial diffusion, ionic conductivity, the annealing rate of radiation damage, and void growth are all influenced by ILMs. The lattice thermal conductivity is suppressed above the ILM activation temperature while no impact is observed in the electrical conductivity. This complement of transport properties suggests that ILMs could improve thermoelectric performance. Ramifications also include thermal ratcheting, a transition from brittle to ductile fracture, and possibly a phase transformation in uranium.

  11. The impact of experimental measurement errors on long-term viscoelastic predictions. [of structural materials

    Science.gov (United States)

    Tuttle, M. E.; Brinson, H. F.

    1986-01-01

    The impact of flight error in measured viscoelastic parameters on subsequent long-term viscoelastic predictions is numerically evaluated using the Schapery nonlinear viscoelastic model. Of the seven Schapery parameters, the results indicated that long-term predictions were most sensitive to errors in the power law parameter n. Although errors in the other parameters were significant as well, errors in n dominated all other factors at long times. The process of selecting an appropriate short-term test cycle so as to insure an accurate long-term prediction was considered, and a short-term test cycle was selected using material properties typical for T300/5208 graphite-epoxy at 149 C. The process of selection is described, and its individual steps are itemized.

  12. Impact of material thicknesses on fission observables obtained with the FALSTAFF experimental setup

    Directory of Open Access Journals (Sweden)

    Thulliez L.

    2017-01-01

    Full Text Available In the past years, the fission studies have been mainly focused on thermal fission because most of the current nuclear reactors work in this energy domain. With the development of GEN-IV reactor concepts, mainly working in the fast energy domain, new nuclear data are needed. The FALSTAFF spectrometer under development at CEA-Saclay, France, is a two-arm spectrometer which will provide mass yields before (2V method and after (EV method neutron evaporation and consequently will have access to the neutron multiplicity as a function of mass. The axial ionization chamber, in addition to the kinetic energy value, will measure the energy loss profile of the fragment along its track. This energy loss profile will give information about the fragment nuclear charge. This paper will focus on recent developments on the FALSTAFF design. A special attention will be paid to the impact of the detector material thickness on the uncertainty of different observables.

  13. Early Thermal Evolution of Planetesimals and its Impact on Processing and Dating of Meteoritic Material

    CERN Document Server

    Gail, H -P; Breuer, D; Spohn, T

    2013-01-01

    Radioisotopic ages for meteorites and their components provide constraints on the evolution of small bodies: timescales of accretion, thermal and aqueous metamorphism, differentiation, cooling and impact metamorphism. Realising that the decay heat of short-lived nuclides (e.g. 26Al, 60Fe), was the main heat source driving differentiation and metamorphism, thermal modeling of small bodies is of utmost importance to set individual meteorite age data into the general context of the thermal evolution of their parent bodies, and to derive general conclusions about the nature of planetary building blocks in the early solar system. As a general result, modelling easily explains that iron meteorites are older than chondrites, as early formed planetesimals experienced a higher concentration of short-lived nuclides and more severe heating. However, core formation processes may also extend to 10 Ma after formation of Calcium-Aluminum-rich inclusions (CAIs). A general effect of the porous nature of the starting material ...

  14. Navigating Language Barriers: A Systematic Review of Patient Navigators' Impact on Cancer Screening for Limited English Proficient Patients.

    Science.gov (United States)

    Genoff, Margaux C; Zaballa, Alexandra; Gany, Francesca; Gonzalez, Javier; Ramirez, Julia; Jewell, Sarah T; Diamond, Lisa C

    2016-04-01

    To systematically review the literature on the impact of patient navigators on cancer screening for limited English proficient (LEP) patients. Electronic databases (PubMed, PsycINFO via OVID, Web of Science, Cochrane, EMBASE, and Scopus) through 8 May 2015. Articles in this review had: (1) a study population of LEP patients eligible for breast, cervical or colorectal cancer screenings, (2) a patient navigator intervention to provide services prior to or during cancer screening, (3) a comparison of the patient navigator intervention to either a control group or another intervention, and (4) language-specific outcomes related to the patient navigator intervention. We assessed the quality of the articles using the Downs and Black Scale. Fifteen studies met the inclusion criteria and evaluated the screening rates for breast, colorectal, and cervical cancer in 15 language populations. Fourteen studies resulted in improved screening rates for LEP patients between 7 and 60%. There was great variability in the patient navigation interventions evaluated. Training received by navigators was not reported in nine of the studies and no studies assessed the language skills of the patient navigators in English or the target language. This study is limited by the variability in study designs and limited reporting on patient navigator interventions, which reduces the ability to draw conclusions on the full effect of patient navigators. Overall, we found evidence that navigators improved screening rates for breast, cervical and colorectal cancer screening for LEP patients. Future studies should systematically collect data on the training curricula for navigators and assess their English and non-English language skills in order to identify ways to reduce disparities for LEP patients.

  15. Impact of carbonation on the durability of cementitious materials: water transport properties characterization

    Directory of Open Access Journals (Sweden)

    Le Bescop P.

    2013-07-01

    Full Text Available Within the context of long-lived intermediate level radioactive waste geological disposal, reinforced concrete would be used. In service life conditions, the concrete structures would be subjected to drying and carbonation. Carbonation relates to the reaction between carbon dioxide (CO2 and the main hydrates of the cement paste (portlandite and C-S-H. Beyond the fall of the pore solution pH, indicative of steel depassivation, carbonation induces mineralogical and microstructural changes (due to portlandite and C-S-H dissolution and calcium carbonate precipitation. This results in the modification of the transport properties, which can impact the structure durability. Because concrete durability depends on water transport, this study focuses on the influence of carbonation on water transport properties. In fact, the transport properties of sound materials are known but they still remain to be assessed for carbonated ones. An experimental program has been designed to investigate the transport properties in carbonated materials. Four hardened cement pastes, differing in mineralogy, are carbonated in an accelerated carbonation device (in controlled environmental conditions at CO2 partial pressure of about 3%. Once fully carbonated, all the data needed to describe water transport, using a simplified approach, will be evaluated.

  16. Data Collection Handbook to Support Modeling Impacts of Radioactive Material in Soil and Building Structures

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Charley [Argonne National Lab. (ANL), Argonne, IL (United States); Kamboj, Sunita [Argonne National Lab. (ANL), Argonne, IL (United States); Wang, Cheng [Argonne National Lab. (ANL), Argonne, IL (United States); Cheng, Jing-Jy [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-09-01

    This handbook is an update of the 1993 version of the Data Collection Handbook and the Radionuclide Transfer Factors Report to support modeling the impact of radioactive material in soil. Many new parameters have been added to the RESRAD Family of Codes, and new measurement methodologies are available. A detailed review of available parameter databases was conducted in preparation of this new handbook. This handbook is a companion document to the user manuals when using the RESRAD (onsite) and RESRAD-OFFSITE code. It can also be used for RESRAD-BUILD code because some of the building-related parameters are included in this handbook. The RESRAD (onsite) has been developed for implementing U.S. Department of Energy Residual Radioactive Material Guidelines. Hydrogeological, meteorological, geochemical, geometrical (size, area, depth), crops and livestock, human intake, source characteristic, and building characteristic parameters are used in the RESRAD (onsite) code. The RESRAD-OFFSITE code is an extension of the RESRAD (onsite) code and can also model the transport of radionuclides to locations outside the footprint of the primary contamination. This handbook discusses parameter definitions, typical ranges, variations, and measurement methodologies. It also provides references for sources of additional information. Although this handbook was developed primarily to support the application of RESRAD Family of Codes, the discussions and values are valid for use of other pathway analysis models and codes.

  17. Salt content impact on the unsaturated property of bentonite-sand buffer backfilling materials

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Ming [Key Laboratory of Mechanics on Disaster and Environment in Western China, Lanzhou University, Lanzhou 730000 (China); Zhang Huyuan, E-mail: p1314lvp@yahoo.com.cn [Key Laboratory of Mechanics on Disaster and Environment in Western China, Lanzhou University, Lanzhou 730000 (China); Jia Lingyan; Cui Suli [Key Laboratory of Mechanics on Disaster and Environment in Western China, Lanzhou University, Lanzhou 730000 (China)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer SWCC and infiltration process of bentonite-sand mixtures is researched. Black-Right-Pointing-Pointer The k{sub u} of bentonite-sand mixtures was evaluated as the buffer backfilling materials. Black-Right-Pointing-Pointer Salt content impacting on the unsaturated property of bentonite-sand materials is small. - Abstract: Bentonite mixed with sand is often considered as possible engineered barrier in deep high-level radioactive waste disposal in China. In the present work, the vapor transfer technique and water infiltration apparatus were used to measure the soil water characteristic curve (SWCC) and unsaturated hydraulic conductivity (k{sub u}) of bentonite-sand mixtures (B/S) effected by salt content. Results show, the water-holding capacity and k{sub u} increase slightly with the concentration of Na{sup +} in pore liquid increasing from 0 g/L to 12 g/L, similar with the solution concentration of Beishan groundwater in China. Salt content in the laboratory produced only one order of magnitude increase in k{sub u}, which is the 'safe' value. The different pore liquid concentrations used in this study led to small differences in thickness of diffuse double layer of bentonite in mixtures, this might explain why some differences have been found in final values of k{sub u}.

  18. THE IMPACT OF WEB BASED RESOURCE MATERIAL ON LEARNING OUTCOME IN OPEN DISTANCE HIGHER EDUCATION

    Directory of Open Access Journals (Sweden)

    Rehana MASRUR

    2010-04-01

    Full Text Available One of the most powerful educational option in open and distance education is web-based learning. A blended (hybrid course combines traditional face to face and web-based learning approaches in an educational environment that is nonspecific as to time and place. The study reported here investigated the impact of web based resource material practices on MPhil, Teacher Education course of Allama Iqbal Open University A sample of 68 students was selected. Thirty-eight students comprised the control group, whereas another group of 30 students was named as experimental group. The study package of control group included self instruction material comprising of two study guides (six credit hours course, recommended book, four assignments, and assignment submission schedule. Experimental group received the same package plus CD having web based articles related to each unit of study guide, and a list of web sites for further reading. After the submission of assignments a one week workshop was held. Participation in workshop was assessed by the oral presentation of student on the topic assigned to him/her before the commencement of workshop. The final examination was held at the end of semester. The marks obtained by both groups were compared by t-test. The scores of experimental group were higher on all assessment components. The study concluded that integration of IT in teaching-learning increased the understanding of subject related knowledge.

  19. Radiological impact associated to the transport of radioactive material by road in Spain; Impacto radiologico asociado al transporte de material radiactivo por carretera en Espana

    Energy Technology Data Exchange (ETDEWEB)

    Calleja, J. A.; Gutierrez, F.

    2010-07-01

    Questions relating to the transport of radioactive materials are an issue of current interest because of the continuous increase in the mobility of these materials and the increasing commitment of these activities to the environment, the safety and protection of persons and the current legal framework. As a particularly contribution to the radiological impact study associated to the transport, a data-processing application for the treatment of data is propose, which allows progress to be made in this study and which may be of use in association with the legal documentation. Thus, by knowing the level of radiation at a distance of one metre from the transport vehicle and by selecting a route, it is possible to gain insight into the associated impacts, such as the affected populations, the dose received by the most exposed individual, the overall radiological impact and the contributions at population, transport route and national level. In preparing this work, consideration has been given to the relevant information provided by the different organisations involved in the issue (nuclear power plants, transport and inspection companies, etc.). The most important conclusion is that the, under normal operation, annual radiological impact from the transport by road of radioactive material in Spain is very low and does not imply any associated risks. (Author) 8 refs.

  20. Hard-sphere limit of soft-sphere model for granular materials: stiffness dependence of steady granular flow.

    Science.gov (United States)

    Mitarai, Namiko; Nakanishi, Hiizu

    2003-02-01

    Dynamical behavior of steady granular flow is investigated numerically in the inelastic hard-sphere limit of the soft-sphere model. We find distinctively different limiting behaviors for the two flow regimes, i.e., the collisional flow and the frictional flow. In the collisional flow, the hard-sphere limit is straightforward; the number of collisions per particle per unit time converges to a finite value and the total contact time fraction with other particles goes to zero. For the frictional flow, however, we demonstrate that the collision rate diverges as the power of the particle stiffness so that the time fraction of the multiple contacts remains finite even in the hard-sphere limit, although the contact time fraction for the binary collisions tends to zero.

  1. Impact of nanoscale zero valent iron on geochemistry and microbial populations in trichloroethylene contaminated aquifer materials.

    Science.gov (United States)

    Kirschling, Teresa L; Gregory, Kelvin B; Minkley, Edwin G; Lowry, Gregory V; Tilton, Robert D

    2010-05-01

    Nanoscale zerovalent iron (NZVI) particles are a promising technology for reducing trichloroethylene (TCE) contamination in the subsurface. Prior to injecting large quantities of nanoparticles into the groundwater it is important to understand what impact the particles will have on the geochemistry and indigenous microbial communities. Microbial populations are important not only for nutrient cycling, but also for contaminant remediation and heavy metal immobilization. Microcosms were used to determine the effects of NZVI addition on three different aquifer materials from TCE contaminated sites in Alameda Point, CA, Mancelona, MI, and Parris Island, SC. The oxidation and reduction potential of the microcosms consistently decreased by more than 400 mV when NZVI was added at 1.5 g/L concentrations. Sulfate concentrations decreased in the two coastal aquifer materials, and methane was observed in the presence of NZVI in Alameda Point microcosms, but not in the other two materials. Denaturing gradient gel electrophoresis (DGGE) showed significant shifts in Eubacterial diversity just after the Fe(0) was exhausted, and quantitative polymerase chain reaction (qPCR) analyses showed increases of the dissimilatory sulfite reductase gene (dsrA) and Archaeal 16s rRNA genes, indicating that reducing conditions and hydrogen created by NZVI stimulate both sulfate reducer and methanogen populations. Adding NZVI had no deleterious effect on total bacterial abundance in the microcosms. NZVI with a biodegradable polyaspartate coating increased bacterial populations by an order of magnitude relative to controls. The lack of broad bactericidal effect, combined with the stimulatory effect of polyaspartate coatings, has positive implications for NZVI field applications.

  2. Computer-Enriched Instruction (CEI) Is Better for Preview Material Instead of Review Material: An Example of a Biostatistics Chapter, the Central Limit Theorem

    Science.gov (United States)

    See, Lai-Chu; Huang, Yu-Hsun; Chang, Yi-Hu; Chiu, Yeo-Ju; Chen, Yi-Fen; Napper, Vicki S.

    2010-01-01

    This study examines the timing using computer-enriched instruction (CEI), before or after a traditional lecture to determine cross-over effect, period effect, and learning effect arising from sequencing of instruction. A 2 x 2 cross-over design was used with CEI to teach central limit theorem (CLT). Two sequences of graduate students in nursing…

  3. Computer-Enriched Instruction (CEI) Is Better for Preview Material Instead of Review Material: An Example of a Biostatistics Chapter, the Central Limit Theorem

    Science.gov (United States)

    See, Lai-Chu; Huang, Yu-Hsun; Chang, Yi-Hu; Chiu, Yeo-Ju; Chen, Yi-Fen; Napper, Vicki S.

    2010-01-01

    This study examines the timing using computer-enriched instruction (CEI), before or after a traditional lecture to determine cross-over effect, period effect, and learning effect arising from sequencing of instruction. A 2 x 2 cross-over design was used with CEI to teach central limit theorem (CLT). Two sequences of graduate students in nursing…

  4. An experimental study of low velocity impacts into granular material in reduced gravity

    Science.gov (United States)

    Murdoch, Naomi; Avila Martinez, Iris; Sunday, Cecily; Cherrier, Olivier; Zenou, Emanuel; Janin, Tristan; Cadu, Alexandre; Gourinat, Yves; Mimoun, David

    2016-04-01

    The granular nature of asteroid surfaces, in combination with the low surface gravity, makes it difficult to predict lander - surface interactions from existing theoretical models. Nonetheless, an understanding of such interactions is particularly important for the deployment of a lander package. This was demonstrated by the Philae lander, which bounced before coming to rest roughly 1 kilometer away from its intended landing site on the surface of comet 67P/Churyumov-Gerasimenko before coming to rest (Biele et al., 2015). In addition to being important for planning the initial deployment, information about the acceleration profile upon impact is also important in the choice of scientific payloads that want to exploit the initial landing to study the asteroid surface mechanical properties (e.g., Murdoch et al., 2016). Using the ISAE-SUPAERO drop tower, we have performed a series of low-velocity collisions into granular material in low gravity. Reduced-gravity is simulated by releasing a free-falling projectile into a surface container with a downward acceleration less than that of Earth's gravity. The acceleration of the surface is controlled through the use an Atwood machine, or a system of pulleys and counterweights. In reducing the effective surface acceleration of the granular material, the confining pressure will be reduced, and the properties of the granular material will become more representative of those on an asteroid's surface. In addition, since both the surface and projectile are falling, the projectile requires a minimum amount of time to catch the surface before the collision begins. This extended free-fall increases the experiment duration, making it easier to use accelerometers and high-speed cameras for data collection. The experiment is built into an existing 5.5 m drop-tower frame and has required the custom design of all components, including the projectile, surface sample container, release mechanism and deceleration system (Sunday et al., 2016

  5. The potential impact of ozone on materials in the U.K.

    Science.gov (United States)

    Lee, David S.; Holland, Michael R.; Falla, Norman

    Recent reports have highlighted the potential damage caused to a range of media, including materials, by ozone (O 3). The limited data available indicate significant damage to rubber products and surface coatings but either insignificant or unquantifiable damage to textiles and other polymeric materials at the range of atmospheric concentrations encountered in the U.K. Materials in the indoor environment have been excluded from economic analyses. Legislation was put in place in 1993 in the U.K. in order to reduce NO x (NO x = NO + NO 2) and VOC (volatile organic compounds) emissions from motor vehicles which is likely to result in reduced peak O 3 episodes but increased average levels of O 3 in urban areas which may result in increased damage to materials. A detailed assessment of the costs of O 3 damage to materials is not currently possible because of insufficient information on relevant dose-response functions and the stock at risk. Alternative methods were thus adopted to determine the potential scale of the problem. Scaling of U.S. estimates made in the late 1960s provides a range for the U.K. of £170 million-£345 million yr -1 in current terms. This includes damage to surface coatings and elastomers, and the cost of antiozonant protection applied to rubber goods. Independent estimates were made of the costs of protecting rubber goods in the U.K. These were based on the size of the antiozonant market, and provide cost ranges of £25 million-£63 million yr -1 to manufacturers and £25 million-£189 million yr -1 to consumers. The only rubber goods for which a damage estimate (not including protection costs) could be made were tyres, using data from the U.S.A. and information on annual tyre sales in the U.K. A range of £0-£4 million yr -1 was estimated. The cost of damage to other rubber goods could not be quantified because of a lack of data on both the stock at risk and exposure-response functions. The effect of O 3 on the costs of repainting were

  6. THERMAL AND RADIATIVE ACTIVE GALACTIC NUCLEUS FEEDBACK HAVE A LIMITED IMPACT ON STAR FORMATION IN HIGH-REDSHIFT GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Roos, Orianne; Juneau, Stéphanie; Bournaud, Frédéric; Gabor, Jared M., E-mail: orianne.roos@cea.fr [CEA-Saclay, F-91190 Gif-sur-Yvette (France)

    2015-02-10

    The effects of active galactic nuclei (AGNs) on their host galaxies depend on the coupling between the injected energy and the interstellar medium (ISM). Here, we model and quantify the impact of long-range AGN ionizing radiation—in addition to the often considered small-scale energy deposition—on the physical state of the multi-phase ISM of the host galaxy and on its total star formation rate (SFR). We formulate an AGN spectral energy distribution matched with observations, which we use with the radiative transfer (RT) code Cloudy to compute AGN ionization in a simulated high-redshift disk galaxy. We use a high-resolution (∼6 pc) simulation including standard thermal AGN feedback and calculate RT in post-processing. Surprisingly, while these models produce significant AGN-driven outflows, we find that AGN ionizing radiation and heating reduce the SFR by a few percent at most for a quasar luminosity (L {sub bol} = 10{sup 46.5} erg s{sup –1}). Although the circumgalactic gaseous halo can be kept almost entirely ionized by the AGN, most star-forming clouds (n ≳ 10{sup 2} {sup –} {sup 3} cm{sup –3}) and even the reservoirs of cool atomic gas (n ∼ 0.3-10 cm{sup –3})—which are the sites of future star formation (SF; 100-200 Myr), are generally too dense to be significantly affected. Our analysis ignores any absorption from a putative torus, making our results upper limits on the effects of ionizing radiation. Therefore, while the AGN-driven outflows can remove substantial amounts of gas in the long term, the impact of AGN feedback on the SF efficiency in the interstellar gas in high-redshift galaxies is marginal, even when long-range radiative effects are accounted for.

  7. Impact of quantum confinement on transport and the electrostatic driven performance of silicon nanowire transistors at the scaling limit

    Science.gov (United States)

    Al-Ameri, Talib; Georgiev, Vihar P.; Sadi, Toufik; Wang, Yijiao; Adamu-Lema, Fikru; Wang, Xingsheng; Amoroso, Salvatore M.; Towie, Ewan; Brown, Andrew; Asenov, Asen

    2017-03-01

    In this work we investigate the impact of quantum mechanical effects on the device performance of n-type silicon nanowire transistors (NWT) for possible future CMOS applications at the scaling limit. For the purpose of this paper, we created Si NWTs with two channel crystallographic orientations and and six different cross-section profiles. In the first part, we study the impact of quantum corrections on the gate capacitance and mobile charge in the channel. The mobile charge to gate capacitance ratio, which is an indicator of the intrinsic performance of the NWTs, is also investigated. The influence of the rotating of the NWTs cross-sectional geometry by 90° on charge distribution in the channel is also studied. We compare the correlation between the charge profile in the channel and cross-sectional dimension for circular transistor with four different cross-sections diameters: 5 nm, 6 nm, 7 nm and 8 nm. In the second part of this paper, we expand the computational study by including different gate lengths for some of the Si NWTs. As a result, we establish a correlation between the mobile charge distribution in the channel and the gate capacitance, drain-induced barrier lowering (DIBL) and the subthreshold slope (SS). All calculations are based on a quantum mechanical description of the mobile charge distribution in the channel. This description is based on the solution of the Schrödinger equation in NWT cross sections along the current path, which is mandatory for nanowires with such ultra-scale dimensions.

  8. Micro-economic impact of congenital heart surgery: results of a prospective study from a limited-resource setting.

    Directory of Open Access Journals (Sweden)

    Manu Raj

    Full Text Available The microeconomic impact of surgery for congenital heart disease is unexplored, particularly in resource limited environments. We sought to understand the direct and indirect costs related to congenital heart surgery and its impact on Indian households from a family perspective.Baseline and first follow-up data of 644 consecutive children admitted for surgery for congenital heart disease (March 2013 - July 2014 in a tertiary referral hospital in Central Kerala, South India was collected prospectivelyfrom parents through questionnaires using a semi-structured interview schedule.The median age was 8.2 months (IQR: 3.0- 36.0 months. Most families belonged to upper middle (43.0% and lower middle (35.7% socioeconomic class. Only 3.9% of families had some form of health insurance. The median expense for the admission and surgery was INR 201898 (IQR: 163287-266139 [I$ 11989 (IQR: 9696-15804], which was 0.93 (IQR: 0.52-1.49 times the annual family income of affected patients. Median loss of man-days was 35 (IQR: 24-50 and job-days was 15 (IQR: 11-24. Surgical risk category and hospital stay duration significantly predicted higher costs. One in two families reported overwhelming to high financial stress during admission period for surgery. Approximately half of the families borrowed money during the follow up period after surgery.Surgery for congenital heart disease results in significant financial burden for majority of families studied. Efforts should be directed at further reductions in treatment costs without compromising the quality of care together with generating financial support for affected families.

  9. Micro-economic impact of congenital heart surgery: results of a prospective study from a limited-resource setting.

    Science.gov (United States)

    Raj, Manu; Paul, Mary; Sudhakar, Abish; Varghese, Anu Alphonse; Haridas, Aareesh Chittulliparamb; Kabali, Conrad; Kumar, Raman Krishna

    2015-01-01

    The microeconomic impact of surgery for congenital heart disease is unexplored, particularly in resource limited environments. We sought to understand the direct and indirect costs related to congenital heart surgery and its impact on Indian households from a family perspective. Baseline and first follow-up data of 644 consecutive children admitted for surgery for congenital heart disease (March 2013 - July 2014) in a tertiary referral hospital in Central Kerala, South India was collected prospectivelyfrom parents through questionnaires using a semi-structured interview schedule. The median age was 8.2 months (IQR: 3.0- 36.0 months). Most families belonged to upper middle (43.0%) and lower middle (35.7%) socioeconomic class. Only 3.9% of families had some form of health insurance. The median expense for the admission and surgery was INR 201898 (IQR: 163287-266139) [I$ 11989 (IQR: 9696-15804)], which was 0.93 (IQR: 0.52-1.49) times the annual family income of affected patients. Median loss of man-days was 35 (IQR: 24-50) and job-days was 15 (IQR: 11-24). Surgical risk category and hospital stay duration significantly predicted higher costs. One in two families reported overwhelming to high financial stress during admission period for surgery. Approximately half of the families borrowed money during the follow up period after surgery. Surgery for congenital heart disease results in significant financial burden for majority of families studied. Efforts should be directed at further reductions in treatment costs without compromising the quality of care together with generating financial support for affected families.

  10. Features of energy impact on a billet material when cutting with outstripping plastic deformation

    Directory of Open Access Journals (Sweden)

    V. M. Yaroslavtsev

    2014-01-01

    Full Text Available In the last decades the so-called combined machining methods based on parallel, serial or parallelserial combination of different types of energy impacts on the billet are designed and developed. Combination of two or more sources of external energy in one method of machining can be directed to the solution of different technological tasks, such as: improvement of a basic method to enhance technicaland-economic and technological indicators of machining, expansion of technological capabilities of the method, increase of reliability and stability of technological process to produce details, etc. Besides, the combined methods of machining are considered as one of the means, which enables reducing the number of operations in technological process, allows the growth of workforce productivity.When developing the combined technologies, one of the main scientific tasks is to define the general regularities of interaction and mutual influence of the energy fluxes brought to the zone of machining. The result of such mutual influence becomes apparent from the forming technological parameters of machining and determines the most rational operating conditions of technological process.In the context of conducted in BMSTU researches on the combined cutting method with outstripping plastic deformation (OPD the mutual influence of the energetic components of machining has been quantitatively assessed. The paper shows a direct relationship between the rational ratio of the two types of the mechanical energy brought in the machining zone, the machining conditions, and the optimum operating conditions.The paper offers a physical model of chip formation when machining with OPD. The essence of model is that specific works spent on material deformation of a cut-off layer are quantitatively compared at usual cutting and at cutting with OPD. It is experimentally confirmed that the final strain-deformed material states of a cut-off layer, essentially, coincide in both

  11. Survival of Organic Materials in Hypervelocity Impacts of Ice on Sand, Ice, and Water in the Laboratory

    Science.gov (United States)

    Bowden, Stephen A.; Cole, Michael; Parnell, John

    2014-01-01

    Abstract The survival of organic molecules in shock impact events has been investigated in the laboratory. A frozen mixture of anthracene and stearic acid, solvated in dimethylsulfoxide (DMSO), was fired in a two-stage light gas gun at speeds of ∼2 and ∼4 km s−1 at targets that included water ice, water, and sand. This involved shock pressures in the range of 2–12 GPa. It was found that the projectile materials were present in elevated quantities in the targets after impact and in some cases in the crater ejecta as well. For DMSO impacting water at 1.9 km s−1 and 45° incidence, we quantify the surviving fraction after impact as 0.44±0.05. This demonstrates successful transfer of organic compounds from projectile to target in high-speed impacts. The range of impact speeds used covers that involved in impacts of terrestrial meteorites on the Moon, as well as impacts in the outer Solar System on icy bodies such as Pluto. The results provide laboratory evidence that suggests that exogenous delivery of complex organic molecules from icy impactors is a viable source of such material on target bodies. Key Words: Organic—Hypervelocity—Shock—Biomarkers. Astrobiology 14, 473–485. PMID:24901745

  12. Electric Spark Sensitivity of Polynitro Compounds. Part V. A Relationship between Electric Spark and Impact Sensitivities of Energetic Materials

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The spark energy, EES, required for 50 percent initiation probability of 41 polynitro compounds was determined. The relationships between the EES values and impact sensitivity, expressed as drop energies Ed of the "first reaction", were established and discussed. The conclusion is made that depending on intermolecular interaction factors in crystals of energetic materials, the mechanism of impact energy transition to the reaction centre of their molecule can be differ from that of transition of energy of electric spark.

  13. Numerical Analysis Study of the Failure Mechanism of Transparent Materials During Low Velocity Impact Used in Protective Systems

    Science.gov (United States)

    2011-07-01

    magnesium aluminate spinel, aluminum oxynitride — one was selected for the current pursuit, glass. Individual transparent materials used in protective...ones of the face glass A’ of 741-series. Both laminates were impacted by 4340 steel spheres of 19.05 mm and 5.56 mm diameter respectively. The...held together by polyurethane and impacted by steel spheres of 19 mm and 5.56 mm diameter , were simulated using the non-linear ANSYS/AUTODYN

  14. Evidence of impact material and the extinction of the mega-fauna 12,900 years ago

    Science.gov (United States)

    Fayek, M.; Hull, S.; Anovitz, L.; Haynes, V.; Bergen, L.

    2008-12-01

    Approximately 13,000 years ago the landscape of North America was very different from what exists today. The Clovis people were hunting mammoths and other megafauna that roamed the land at the close of the Pleistocene. Evidence of these large mammals and the material remains of the Clovis inhabitants no longer appear in the geological or archeological records after 12,900 years ago. This coincides with the onset of the Younger Dryas (YD) climatic event. The onset of the YD appears to have been relatively abrupt and it lasted for ~1000 yrs. There have been many theories put forth to explain the sudden changes in climate and human culture, and the Pleistocene mega-fauna extinction that appear to have coincided with the onset of the Younger Dryas (YD) climatic event. Few theories, however, have adequately explained the concurrence of all three events. Nevertheless, few researchers disagree that something major happened 12,900 years ago. In 2007, Firestone et al proposed that an extraterrestrial event (ET) (e.g., meteorite impact) caused the onset of YD climatic event, which led to the extinction of the mega-fauna and the collapse for the Clovis culture. Skeptics argue that the ET markers that have been described by Firestone et al are not sufficient evidence to prove the occurrence of an ET event because evidence for an ET event such as an impact crater, tektites, shocked quartz, high temperature minerals, and impact material are absent. Here we present for the first time chemical and textural evidence of impact material from the Clovis-age, Murray Springs "black mat" layer, Arizona, USA. The impact material contains iron oxide spherules (framboids) in a glassy iron-silica matrix, which is one indicator of a possible meteorite impact. Chemical analyses of these spherules and the glassy matrices found in the particles from the larger size fractions are compared to the chemistry of carbonaceous chondrites, impact material associated with meteorite showers and meteorite

  15. [The impact factor: a factor of impact or the impact of a (sole) factor? The limits of a bibliometric indicator as a candidate for an instrument to evaluate scientific production].

    Science.gov (United States)

    Gensini, G F; Conti, A A

    1999-01-01

    The Impact Factor is a bibliometric quantitative parameter introduced in 1971 and used to evaluate, classify and compare scientific journals. It is essentially the ratio between the number of citations they receive, computed on the basis of those included in the Science Citation Index, and the number of published articles. It is thus a dynamic parameter and an indicator of the editorial quality of a journal. It has also been considered a putative index of the scientific production of a single author. The Impact Factor was first proposed as a useful instrument for planning library choices, programming personal journal buying and reading, and directing scientific journal editors in their editorial strategies. However, since among the numerous variables which may influence the Impact Factor there are such parameters as: the average number of bibliographical references in a single article, self-citations, "salami publications", the Impact Factor, though adequate to judge entities such as journals, institutions and whole scientific communities, seems on the contrary inadequate to evaluate accurately the quality of the single investigator, paper, and research group. Furthermore, a limited number of papers, all focused on the so-called "hot topics", may contribute to increase the Impact Factor of a single journal. There is therefore still much research to be done to find truly "objective" methods to evaluate critically the "quality" (and not only the "quantity") of the work of a single author, a scientific group, and an entire institution, so that not only quantitative, but also qualitative evidence may be acquired!

  16. Impact of High Concentration Solutions on Hydraulic Properties of Geosynthetic Clay Liner Materials

    Directory of Open Access Journals (Sweden)

    Lei Liu

    2012-11-01

    Full Text Available This study focuses on the impact of landfill high concentration solutions erosion on geosynthetic clay liner (GCL materials permeability. The permeation tests on the GCL, submerged using different kinds of solutions with different concentrations, were carried out systematically by taking these chemical solutions as permeant liquids. Based on seasonal variations of ion concentrations in Chenjiachong landfill leachate (Wuhan Province, CaCl2, MgCl2, NaCl, and KCl were selected as chemical attack solutions to carry out experimental investigations under three concentrations (50 mM, 100 mM, 200 mM and soak times (5, 10, and 20 days. The variation law of the GCL hydraulic conductivity under different operating conditions was analyzed. The relationship between GCL hydraulic conductivity, chemical solutions categories, concentrations, and soak times were further discussed. The GCL hydraulic conductivity, when soaked and permeated with high concentration chemical solutions, increases several times or exceeds two orders of magnitude, as compared with the permeation test under normal conditions that used water as the permeant liquid. This reveals that GCL is very susceptible to chemical attack. For four chemical solutions, the chemical attack effect on GCL hydraulic conductivity is CaCl2 > MgCl2 > KCl > NaCl. The impact of soak times on GCL hydraulic conductivity is the cooperative contribution of the liner chemical attack reaction and hydration swelling. A longer soak time results in a more advantageous hydration swelling effect. The chemical attack reaction restrains the hydration swelling of the GCL. Moreover, the GCL hydraulic conductivity exponentially decreases with the increased amplitude of thickness.

  17. DWPF COAL-CARBON WASTE ACCEPTANCE CRITERIA LIMIT EVALUATION BASED ON EXPERIMENTAL WORK (TANK 48 IMPACT STUDY)

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, D.; Choi, A.

    2010-10-15

    This report summarizes the results of both experimental and modeling studies performed using Sludge Batch 10 (SB10) simulants and FBSR product from Tank 48 simulant testing in order to develop higher levels of coal-carbon that can be managed by DWPF. Once the Fluidized Bed Steam Reforming (FBSR) process starts up for treatment of Tank 48 legacy waste, the FBSR product stream will contribute higher levels of coal-carbon in the sludge batch for processing at DWPF. Coal-carbon is added into the FBSR process as a reductant and some of it will be present in the FBSR product as unreacted coal. The FBSR product will be slurried in water, transferred to Tank Farm and will be combined with sludge and washed to produce the sludge batch that DWPF will process. The FBSR product is high in both water soluble sodium carbonate and unreacted coal-carbon. Most of the sodium carbonate is removed during washing but all of the coal-carbon will remain and become part of the DWPF sludge batch. A paper study was performed earlier to assess the impact of FBSR coal-carbon on the DWPF Chemical Processing Cell (CPC) operation and melter off-gas flammability by combining it with SB10-SB13. The results of the paper study are documented in Ref. 7 and the key findings included that SB10 would be the most difficult batch to process with the FBSR coal present and up to 5,000 mg/kg of coal-carbon could be fed to the melter without exceeding the off-gas flammability safety basis limits. In the present study, a bench-scale demonstration of the DWPF CPC processing was performed using SB10 simulants spiked with varying amounts of coal, and the resulting seven CPC products were fed to the DWPF melter cold cap and off-gas dynamics models to determine the maximum coal that can be processed through the melter without exceeding the off-gas flammability safety basis limits. Based on the results of these experimental and modeling studies, the presence of coal-carbon in the sludge feed to DWPF is found to have

  18. Microfluidic encapsulation for self-healing material and investigation of its impacts on composite performance

    Science.gov (United States)

    Lemmens, Ryan J.

    Encapsulation is a key enabling technology of self-healing materials for which incorporation of reactive materials into a composite, without loss of functionality, is required for damage repair. The functionalized particles resulting from such processes must be readily incorporable into a composite and have minimal detrimental impact on its undamaged properties. At the same time, their morphology must preferentially promote the release of their content during a damage event. However, there is still a need for new techniques capable of fine tuning particle properties for the controlled design of composite performance. To introduce superior processing control, two microfluidics based encapsulation processes have been developed, one each for the individual components of a two-part chemical healing system, namely dicyclopentadiene and Grubb's catalyst. These processes have enabled significantly enhanced performance of self-healing epoxy composites by introducing unprecedented control over particle morphology. The microfluidics based encapsulation platform is first demonstrated by emulsification, using droplet microfluidics, and subsequent encapsulation of dicyclopentadiene. The reported approach allows for facile control of mean microcapsule diameter thru variation of fluid flow rates. The microcapsules exhibit coefficients of variation (CV) of diameter in the range 1-3 (i.e. monodisperse is typically defined as CV smaller than 5), an order of magnitude reduction when compared with conventional batch emulsification methods whose typical CV is 20-40. This control over microcapsule uniformity has led to significant improvement in self-healing composite performance as exemplified by ˜25% higher undamaged fracture toughness. A microfluidic solution spinning process is then developed to encapsulate Grubb's catalyst, the most expensive component of this particular material system, in a novel fibrous morphology. The continuous, on-chip fiber production allows for

  19. Limits in virus filtration capability? Impact of virus quality and spike level on virus removal with xenotropic murine leukemia virus.

    Science.gov (United States)

    Roush, David J; Myrold, Adam; Burnham, Michael S; And, Joseph V; Hughes, Joseph V

    2015-01-01

    Virus filtration (VF) is a key step in an overall viral clearance process since it has been demonstrated to effectively clear a wide range of mammalian viruses with a log reduction value (LRV) > 4. The potential to achieve higher LRV from virus retentive filters has historically been examined using bacteriophage surrogates, which commonly demonstrated a potential of > 9 LRV when using high titer spikes (e.g. 10(10) PFU/mL). However, as the filter loading increases, one typically experiences significant decreases in performance and LRV. The 9 LRV value is markedly higher than the current expected range of 4-5 LRV when utilizing mammalian retroviruses on virus removal filters (Miesegaes et al., Dev Biol (Basel) 2010;133:3-101). Recent values have been reported in the literature (Stuckey et al., Biotech Progr 2014;30:79-85) of LRV in excess of 6 for PPV and XMuLV although this result appears to be atypical. LRV for VF with therapeutic proteins could be limited by several factors including process limits (flux decay, load matrix), virus spike level and the analytical methods used for virus detection (i.e. the Limits of Quantitation), as well as the virus spike quality. Research was conducted using the Xenotropic-Murine Leukemia Virus (XMuLV) for its direct relevance to the most commonly cited document, the International Conference of Harmonization (ICH) Q5A (International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use, Geneva, Switzerland, 1999) for viral safety evaluations. A unique aspect of this work is the independent evaluation of the impact of retrovirus quality and virus spike level on VF performance and LRV. The VF studies used XMuLV preparations purified by either ultracentrifugation (Ultra 1) or by chromatographic processes that yielded a more highly purified virus stock (Ultra 2). Two monoclonal antibodies (Mabs) with markedly different filtration characteristics and with similar levels of

  20. Environmental impact assessment of contaminated materials based on ecotoxicological relevance of mobile/bioavailable fractions

    Energy Technology Data Exchange (ETDEWEB)

    Cagigal, E.; Bonilla, A.; Urzelai, A. [Labein Technological Centre, Bilbao (Spain); Diaz, A.; Gorostiza, I. [Foundation Gaiker, Parque Tecnologico, Zamudio (Bizkaia) (Spain)

    2002-07-01

    Chemical analyses in conjunction with leachate and speciation tests provide information about the presence and concentration of contaminants as well as the mobility of these contaminants. However, they are not able to predict the harmful biological or ecological effects. Current study aims to assess the environmental/ecological risks associated to contaminated soil, sediments or wastes. This assessment takes in consideration the analysis of leachate toxicity using bioassays. Bioassays provide direct evidence of ecological effects associated with soil and groundwater pollution, complementing conventional chemical analysis. Conventional biological tests are based on the exposition of organisms to the pollutants and contaminated media of interest. These tests are performed in solid phase being expensive, and space and time consuming. Our approach considers the use of bioassays traditionally applied in water monitoring or leachate ecotoxicity assessment. These methods are cheaper and have a quick response. This approach requires the development of extraction procedures to be used in conjunction with bioassays to determine the hazards due to soluble molecules, less soluble, soil bound molecules, etc. The combined application of extraction-leaching tests/bioassays/physico-chemical analysis on samples, will provide us a wide and complete information about the presence, behaviour and toxicity of pollutants in the tested materials. Final objective of the project is the development of a procedure to be used as a tool for the assessment of environmental impact of contaminated materials. On the framework of the project two mobility/bioavailability tests for both inorganic and organic compounds, and an ecotoxicological assay of the mobile/bioavailable fractions have been applied. Toxicity tests on solid phase were also carried out in order to assess the representativeness of the leaching protocols as a method to reproduce bioavailability of contaminants. (orig.)

  1. Impact of Water Chemistry, Pipe Material and Stagnation on the Building Plumbing Microbiome.

    Directory of Open Access Journals (Sweden)

    Pan Ji

    Full Text Available A unique microbiome establishes in the portion of the potable water distribution system within homes and other buildings (i.e., building plumbing. To examine its composition and the factors that shape it, standardized cold water plumbing rigs were deployed at the treatment plant and in the distribution system of five water utilities across the U.S. Three pipe materials (copper with lead solder, CPVC with brass fittings or copper/lead combined pipe were compared, with 8 hour flush cycles of 10 minutes to simulate typical daily use patterns. High throughput Illumina sequencing of 16S rRNA gene amplicons was employed to profile and compare the resident bulk water bacteria and archaea. The utility, location of the pipe rig, pipe material and stagnation all had a significant influence on the plumbing microbiome composition, but the utility source water and treatment practices were dominant factors. Examination of 21 water chemistry parameters suggested that the total chlorine concentration, pH, P, SO42- and Mg were associated with the most of the variation in bulk water microbiome composition. Disinfectant type exerted a notably low-magnitude impact on microbiome composition. At two utilities using the same source water, slight differences in treatment approaches were associated with differences in rare taxa in samples. For genera containing opportunistic pathogens, Utility C samples (highest pH of 9-10 had the highest frequency of detection for Legionella spp. and lowest relative abundance of Mycobacterium spp. Data were examined across utilities to identify a true universal core, special core, and peripheral organisms to deepen insight into the physical and chemical factors that shape the building plumbing microbiome.

  2. Near-infrared spectroscopy (NIRS) of epilithic material in streams has a potential for monitoring impact from mining.

    Science.gov (United States)

    Persson, Jan; Nilsson, Mats; Bigler, Christian; Brooks, Stephen J; Renberg, Ingemar

    2007-04-15

    There is an increasing demand for cost-effective methods for environmental monitoring, and here we assess the potential of near-infrared spectroscopy (NIRS) on epilithic material from streams (material covering submerged stones) as a new method for monitoring the impact of pollution from mining and mining-related industries. NIRS, a routine technique in industry, registers the chemical properties of organic material on a molecular level and can detect minute alterations in the composition of epilithic material. Epilithic samples from 65 stream sites (42 uncontaminated and 23 contaminated) in northern Sweden were analyzed. The NIRS approach was evaluated by comparing it with the results of chemical analyses and diatom analyses of the same samples. Based on Principal Component Analysis, the NIRS data distinguished contaminated from uncontaminated sites and performed slightly betterthan chemical analyses and clearly betterthan diatom analyses. Of the streams designated a priori as contaminated, 74% were identified as contaminated by NIRS, 65% were identified by chemical analysis, and 26% were identified by diatom analysis. Unlike chemical analyses of water samples, NIRS data reflect biological impacts in the streams, and the epilithic material integrates impact over time. Given that, and the simplicity of NIRS-analyses, further studies to assess the use of NIRS of epilithic material as an inexpensive environmental monitoring method are justified.

  3. Investigations on the Impact of Material-Integrated Sensors with the Help of FEM-Based Modeling

    Directory of Open Access Journals (Sweden)

    Gerrit Dumstorff

    2015-01-01

    Full Text Available We present investigations on the impact of material-integrated sensors with the help of finite element-based modeling. A sensor (inlay integrated with a material (matrix is always a foreign body in the material, which can lead to a “wound effect”, that is degradation of the macroscopic behavior of a material. By analyzing the inlay’s impact on the material in terms of mechanical load, heat conduction, stress during integration and other impacts of integration, this wound effect is analyzed. For the mechanical load, we found out that the inlay has to be at least as stretchable and bendable as the matrix. If there is a high thermal load during integration, the coefficients of the thermal expansion of the inlay have to be matched to the matrix. In the case of a high thermal load during operation, the inlay has to be as thin as possible or its thermal conductivity has to be adapted to the thermal conductivity of the matrix. To have a general view of things, the results are dimensionless and independent of the geometry. In each section, the results are illustrated by examples. Based on all of the results, we present our idea for the fabrication of future material-integrated sensors.

  4. Frequency Comb Generation in 300 nm Thick SiN Concentric-Racetrack-Resonators: Overcoming the Material Dispersion Limit

    CERN Document Server

    Kim, Sangsik; Wang, Cong; Jaramillo-Villegas, Jose A; Xue, Xiaoxiao; Bao, Chengying; Xuan, Yi; Leaird, Daniel E; Weiner, Andrew M; Qi, Minghao

    2016-01-01

    Kerr nonlinearity based frequency combs and solitons have been generated from on-chip optical microresonators with high quality factors and global or local anomalous dispersion. However, fabrication of such resonators usually requires materials and/or processes that are not standard in semiconductor manufacturing facilities. Moreover, in certain frequency regimes such as visible and ultra-violet, the large normal material dispersion makes it extremely difficult to achieve anomalous dispersion. Here we present a concentric racetrack-shaped resonator that achieves anomalous dispersion in a 300 nm thick silicon nitride film, suitable for semiconductor manufacturing but previously thought to result only in waveguides with high normal dispersion, a high intrinsic Q of 1.5 million, and a novel mode-selective coupling scheme that allows coherent combs to be generated. We also provide evidence suggestive of soliton-like pulse formation in the generated comb. Our method can achieve anomalous dispersion over moderately...

  5. Experimental and Theoretical Investigations of the Impact Localization of a Passive Smart Composite Plate Fabricated Using Piezoelectric Materials

    Directory of Open Access Journals (Sweden)

    M. M. S. Dezfouli

    2013-01-01

    Full Text Available Two passive smart composite plates are fabricated using one and two PZT patches that are cheaper than the PZT wafer. The composite plate is fabricated in low temperature through the hand lay-up method to avoid PZT patch decoupling and wire spoiling. The locus of the impact point is identified using the output voltage to identify the impact location using one sensor. The output voltages of the sensors are analyzed to identify the impact location using two sensors. The locations of the impacts are determined based on the crossing points of two circles and the origin of an intended Cartesian coordinate system that is concentric with one of the sensors. This study proposes the impact location identification of the passive smart composite using the low-cost PZT patch PIC155 instead of common embedded materials (wafer and element piezoelectric.

  6. Radiological impact associated with the transport by road of radioactive material in Spain; Impact radiologique lie au transport par route de matieres radioactives en Espagne

    Energy Technology Data Exchange (ETDEWEB)

    Calleja, J.A. [TECNATOM, Prevention Service, Avenida Montes de Oca 1, 28703 San Sebastian de los Reyes, Madrid (Spain); EUITI, Dept. Electrical Engineering, Polytechnic University of Madrid (Spain); Gutierrez, F. [EUITI, Dept. Industrial and Polymer Chemistry, Polytechnic University of Madrid, Madrid (Spain)

    2011-07-15

    Questions relating to the transport of radioactive materials are very much an issue of current interest due to the increasing mobility of the materials involved in the nuclear fuel cycle, commitment to the environment, the safety and protection of persons and the corresponding regulatory legal framework. The radiological impact associated with this type of transport was assessed by means of a new data-processing tool that may be of use and serve as complementary documentation to that included in transport regulations. Thus, by determining the level of radiation at a distance of one metre from the transport vehicle and by selecting a route, the associated impacts will be obtained, such as the affected populations, the dose received by the most highly exposed individual, the overall radiological impact, the doses received by the population along the route and the possible detriment to their health. The most important conclusion is that the emissions of ionising radiation from the transport of radioactive material by road in Spain are not significant as regards the generation of adverse effects on human health, and that their radiological impact may be considered negligible. (authors)

  7. Comparison of impact force attenuation by various combinations of hip protector and flooring material using a simplified fall-impact simulation device.

    Science.gov (United States)

    Li, Ning; Tsushima, Eiki; Tsushima, Hitoshi

    2013-04-01

    Use of hip protectors and compliant flooring has been recommended for preventing hip fracture due to falls. We aimed to identify the factors attenuating forces in falls by comparing and analyzing the impact forces occurring with various combinations of hip protectors and flooring materials. We designed a simplified pendulum device to simulate the impact force at the hip during falling. The impact force was measured on pressure-sensitive recording film under combined conditions of two kinds of hip protector (hard or soft shell) and three kinds of floor material (concrete, wooden, or tatami matting). We then calculated the percentage force attenuation under each test condition compared with the use of a concrete floor and no hip protector. All the tests using tatami matting reduced the impact to below the average fracture threshold of elderly people (3472N). A combination of tatami and soft hip protector provided the best attenuation (72.5%). Multiple regression analyses showed that use of tatami matting and a soft hip protector had the biggest force-attenuation effect. The soft hip protector gave better percentage force attenuation than did the hard one. Use of tatami matting as a flooring material could be an effective strategy for helping prevent hip fractures.

  8. THE IMPACT OF THE SURFACE MORPHOLOGY ON ENERGY CHARACTERISTICS OF NANOPOROUS CARBON MATERIAL

    Directory of Open Access Journals (Sweden)

    B.K. Ostafiychuk

    2014-05-01

    Full Text Available The impact of nanoporous carbon material (PCM morphology on its electrochemical behavior in aqueous electrolyte has been studied. The optimum concentration of aqueous lithium sulfate which provides the maximum specific energy characteristics of capacitor-type systems C/Li2SO4/C is determined. Capacitive parameters of electrochemical capacitors (EC in aqueous so­lutions of lithium, sodium and potassium sulfate which have different molar ratio have been stu­died by comparative analysis. Cyclic voltammograms at different scan rates show that the PCM ca­pacitive behavior in three electrolytes increases in the following order Li2SO4

  9. THE IMPACT OF SELECTED TECHNOLOGICAL AND MATERIAL PARAMETERS ON THE STRENGTH OF ADHESIVE STEEL SHEETS JOINTS

    Directory of Open Access Journals (Sweden)

    Anna Rudawska

    2017-06-01

    Full Text Available The following paper analyses selected problems regarding the impact of technological parameters and type of adherend material on the strength of adhesive-bonded steel sheet joints. The subject of the test was a single-lap adhesive joint of S235JR steel sheet. Joints were formed on two types of substrates: with or without corrosion products on the surface. The surface of steel sheet adherends was pre-treated with three cleaning solutions: acetone, Wiko industrial degreasing agent and Cortanin F anti-corrosion agent, depend-ing on the state of the surface. Adhesive joints were formed with Epidian 53/ET/100:15 epoxy adhesive. The formed joints were subjected to one of three ageing variants: 14 days, two months and 3 months, which were followed by destructive testing to determine the shear strength of joints. The analysis of results ob-tained in tests indicates that the strength performance of adhesive joints of corrosion-free adherends was characterised by higher values than in corroded steel sheets, regardless of ageing time.

  10. Hypervelocity Impact Testing of Materials for Additive Construction: Applications on Earth, the Moon, and Mars

    Science.gov (United States)

    Ordonez, Erick; Edmunson, Jennifer; Fiske, Michael; Christiansen, Eric; Miller, Josh; Davis, Bruce Alan; Read, Jon; Johnston, Mallory; Fikes, John

    2017-01-01

    Additive Construction is the process of building infrastructure such as habitats, garages, roads, berms, etcetera layer by layer (3D printing). The National Aeronautics and Space Administration (NASA) and the United States Army Corps of Engineers (USACE) are pursuing additive construction to build structures using resources available in-situ. Using materials available in-situ reduces the cost of planetary missions and operations in theater. The NASA team is investigating multiple binders that can be produced on planetary surfaces, including the magnesium oxide-based Sorel cement; the components required to make Ordinary Portland Cement (OPC), the common cement used on Earth, have been found on Mars. The availability of OPC-based concrete on Earth drove the USACE to pursue additive construction for base housing and barriers for military operations. Planetary and military base structures must be capable of resisting micrometeoroid impacts with velocities ranging from 11 to 72km/s for particle sizes 200 micrometers or more (depending on protection requirements) as well as bullets and shrapnel with a velocity of 1.036km/s with projectiles 5.66mm diameter and 57.40mm in length, respectively.

  11. The biological impacts of ingested radioactive materials on the pale grass blue butterfly.

    Science.gov (United States)

    Nohara, Chiyo; Hiyama, Atsuki; Taira, Wataru; Tanahara, Akira; Otaki, Joji M

    2014-05-15

    A massive amount of radioactive materials has been released into the environment by the Fukushima Dai-ichi Nuclear Power Plant accident, but its biological impacts have rarely been examined. Here, we have quantitatively evaluated the relationship between the dose of ingested radioactive cesium and mortality and abnormality rates using the pale grass blue butterfly, Zizeeria maha. When larvae from Okinawa, which is likely the least polluted locality in Japan, were fed leaves collected from polluted localities, mortality and abnormality rates increased sharply at low doses in response to the ingested cesium dose. This dose-response relationship was best fitted by power function models, which indicated that the half lethal and abnormal doses were 1.9 and 0.76 Bq per larva, corresponding to 54,000 and 22,000 Bq per kilogram body weight, respectively. Both the retention of radioactive cesium in a pupa relative to the ingested dose throughout the larval stage and the accumulation of radioactive cesium in a pupa relative to the activity concentration in a diet were highest at the lowest level of cesium ingested. We conclude that the risk of ingesting a polluted diet is realistic, at least for this butterfly, and likely for certain other organisms living in the polluted area.

  12. The biological impacts of ingested radioactive materials on the pale grass blue butterfly

    Science.gov (United States)

    Nohara, Chiyo; Hiyama, Atsuki; Taira, Wataru; Tanahara, Akira; Otaki, Joji M.

    2014-05-01

    A massive amount of radioactive materials has been released into the environment by the Fukushima Dai-ichi Nuclear Power Plant accident, but its biological impacts have rarely been examined. Here, we have quantitatively evaluated the relationship between the dose of ingested radioactive cesium and mortality and abnormality rates using the pale grass blue butterfly, Zizeeria maha. When larvae from Okinawa, which is likely the least polluted locality in Japan, were fed leaves collected from polluted localities, mortality and abnormality rates increased sharply at low doses in response to the ingested cesium dose. This dose-response relationship was best fitted by power function models, which indicated that the half lethal and abnormal doses were 1.9 and 0.76 Bq per larva, corresponding to 54,000 and 22,000 Bq per kilogram body weight, respectively. Both the retention of radioactive cesium in a pupa relative to the ingested dose throughout the larval stage and the accumulation of radioactive cesium in a pupa relative to the activity concentration in a diet were highest at the lowest level of cesium ingested. We conclude that the risk of ingesting a polluted diet is realistic, at least for this butterfly, and likely for certain other organisms living in the polluted area.

  13. 9β Polymorphism of the Glucocorticoid Receptor Gene Appears to Have Limited Impact in Patients with Addison’s Disease

    Science.gov (United States)

    Ross, Ian Louis; Dandara, Collet; Swart, Marelize; Lacerda, Miguel; Schatz, Desmond; Blom, Dirk Jacobus

    2014-01-01

    Background Addison’s disease (AD) has been associated with an increased risk of cardiovascular disease. Glucocorticoid receptor polymorphisms that alter glucocorticoid sensitivity may influence metabolic and cardiovascular risk factors in patients with AD. The 9β polymorphism of the glucocorticoid receptor gene is associated with relative glucocorticoid resistance and has been reported to increase the risk of myocardial infarction in the elderly. We explored the impact of this polymorphism in patients with AD. Materials and Methods 147 patients with AD and 147 age, gender and ethnicity matched healthy controls were recruited. Blood was taken in a non-fasted state for plasma lipid determination, measurement of cardiovascular risk factors and DNA extraction. Results Genotype data for the 9β polymorphism was available for 139 patients and 146 controls. AD patients had a more atherogenic lipid profile characterized by an increase in the prevalence of small dense LDL (p = 0.003), increased triglycerides (p = 0.002), reduced HDLC (p<0.001) an elevated highly sensitive C-reactive protein (p = 0.01), compared with controls. The 9β polymorphism (at least one G allele) was found in 28% of patients and controls respectively. After adjusting for age, gender, ethnicity, BMI and hydrocortisone dose per metre square of body surface area in patients, there were no significant metabolic associations with this polymorphism and hydrocortisone doses were not higher in patients with the polymorphism. Conclusions This study did not identify any associations between the 9β polymorphism and cardiovascular risk factors or hydrocortisone dose and determination of this polymorphism is therefore unlikely to be of clinical benefit in the management of patients with AD. PMID:24466047

  14. 9β Polymorphism of the glucocorticoid receptor gene appears to have limited impact in patients with Addison's disease.

    Directory of Open Access Journals (Sweden)

    Ian Louis Ross

    Full Text Available BACKGROUND: Addison's disease (AD has been associated with an increased risk of cardiovascular disease. Glucocorticoid receptor polymorphisms that alter glucocorticoid sensitivity may influence metabolic and cardiovascular risk factors in patients with AD. The 9β polymorphism of the glucocorticoid receptor gene is associated with relative glucocorticoid resistance and has been reported to increase the risk of myocardial infarction in the elderly. We explored the impact of this polymorphism in patients with AD. MATERIALS AND METHODS: 147 patients with AD and 147 age, gender and ethnicity matched healthy controls were recruited. Blood was taken in a non-fasted state for plasma lipid determination, measurement of cardiovascular risk factors and DNA extraction. RESULTS: Genotype data for the 9β polymorphism was available for 139 patients and 146 controls. AD patients had a more atherogenic lipid profile characterized by an increase in the prevalence of small dense LDL (p = 0.003, increased triglycerides (p = 0.002, reduced HDLC (p<0.001 an elevated highly sensitive C-reactive protein (p = 0.01, compared with controls. The 9β polymorphism (at least one G allele was found in 28% of patients and controls respectively. After adjusting for age, gender, ethnicity, BMI and hydrocortisone dose per metre square of body surface area in patients, there were no significant metabolic associations with this polymorphism and hydrocortisone doses were not higher in patients with the polymorphism. CONCLUSIONS: This study did not identify any associations between the 9β polymorphism and cardiovascular risk factors or hydrocortisone dose and determination of this polymorphism is therefore unlikely to be of clinical benefit in the management of patients with AD.

  15. An experiment to test advanced materials impacted by intense proton pulses at CERN HiRadMat facility

    Energy Technology Data Exchange (ETDEWEB)

    Bertarelli, A., E-mail: alessandro.bertarelli@cern.ch [CERN, Engineering Department, Mechanical and Materials Engineering Group (EN-MME), CH-1211 Geneva 23 (Switzerland); Berthome, E. [CERN, Engineering Department, Mechanical and Materials Engineering Group (EN-MME), CH-1211 Geneva 23 (Switzerland); Boccone, V. [CERN, Engineering Department, Sources, Targets and Interactions Group (EN-STI), CH-1211 Geneva 23 (Switzerland); Carra, F. [CERN, Engineering Department, Mechanical and Materials Engineering Group (EN-MME), CH-1211 Geneva 23 (Switzerland); Cerutti, F. [CERN, Engineering Department, Sources, Targets and Interactions Group (EN-STI), CH-1211 Geneva 23 (Switzerland); Charitonidis, N. [CERN, Engineering Department, Machines and Experimental Facilities Group (EN-MEF), CH-1211 Geneva 23 (Switzerland); École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland); Charrondiere, C. [CERN, Engineering Department, Industrial Controls and Engineering Group (EN-ICE), CH-1211 Geneva 23 (Switzerland); Dallocchio, A.; Fernandez Carmona, P.; Francon, P.; Gentini, L.; Guinchard, M.; Mariani, N. [CERN, Engineering Department, Mechanical and Materials Engineering Group (EN-MME), CH-1211 Geneva 23 (Switzerland); Masi, A. [CERN, Engineering Department, Sources, Targets and Interactions Group (EN-STI), CH-1211 Geneva 23 (Switzerland); Marques dos Santos, S.D.; Moyret, P. [CERN, Engineering Department, Mechanical and Materials Engineering Group (EN-MME), CH-1211 Geneva 23 (Switzerland); Peroni, L. [Politecnico di Torino, Department of Mechanical and Aerospace Engineering (DIMEAS), Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Redaelli, S. [CERN, Beams Department, Accelerators and Beams Physics Group (BE-ABP), CH-1211 Geneva 23 (Switzerland); Scapin, M. [Politecnico di Torino, Department of Mechanical and Aerospace Engineering (DIMEAS), Corso Duca degli Abruzzi 24, 10129 Torino (Italy)

    2013-08-01

    Predicting the consequences of highly energetic particle beams impacting protection devices as collimators or high power target stations is a fundamental issue in the design of state-of-the-art facilities for high-energy particle physics. These complex dynamic phenomena can be successfully simulated resorting to highly non-linear numerical tools (Hydrocodes). In order to produce accurate results, however, these codes require reliable material constitutive models that, at the extreme conditions induced by a destructive beam impact, are scarce and often inaccurate. In order to derive or validate such models a comprehensive, first-of-its-kind experiment has been recently carried out at CERN HiRadMat facility: performed tests entailed the controlled impact of intense and energetic proton pulses on a number of specimens made of six different materials. Experimental data were acquired relying on embedded instrumentation (strain gauges, temperature probes and vacuum sensors) and on remote-acquisition devices (laser Doppler vibrometer and high-speed camera). The method presented in this paper, combining experimental measurements with numerical simulations, may find applications to assess materials under very high strain rates and temperatures in domains well beyond particle physics (severe accidents in fusion and fission nuclear facilities, space debris impacts, fast and intense loadings on materials and structures etc.)

  16. The Impact of Differentiated Instructional Materials on English Language Learner (ELL) Students' Comprehension of Science Laboratory Tasks

    Science.gov (United States)

    Manavathu, Marian; Zhou, George

    2012-01-01

    Through a qualitative research design, this article investigates the impacts of differentiated laboratory instructional materials on English language learners' (ELLs) laboratory task comprehension. The factors affecting ELLs' science learning experiences are further explored. Data analysis reveals a greater degree of laboratory task comprehension…

  17. A comparison of finite element analysis to smooth particle hydrodynamics for application to projectile impact on cementitious material

    Science.gov (United States)

    Nordendale, Nikolas A.; Heard, William F.; Sherburn, Jesse A.; Basu, Prodyot K.

    2016-03-01

    The response of structural components of high-strength cementitious (HSC) materials to projectile impact is characterized by high-rate fragmentation resulting from strong compressive shock waves coupled with reflected tensile waves. Accurate modeling of armor panels of such brittle materials under high-velocity projectile impact is a complex problem requiring meticulous experimental characterization of material properties. In a recent paper by the authors, an approach to handle such problems based on a modified Advanced Fundamental Concrete (AFC) constitutive model was developed. In the HSC panels considered in this study, an analogous approach is applied, and the predictions are verified with ballistic impact test data. Traditional Lagrangian finite element analysis (FEA) of these problems tends to introduce errors and suffers from convergence issues resulting from large deformations at free surfaces. Also, FEA cannot properly account for the issues of secondary impact of spalled fragments when multiple armor panels are used. Smoothed particle hydrodynamics (SPH) is considered to be an attractive alternative to resolve these and other issues. However, SPH-based quantitative results have been found to be less accurate than the FEA-based ones when the deformations are not sufficiently large. This paper primarily focuses on a comparison of FEA and SPH models to predict high-velocity projectile impact on single and stacked HSC panels. Results are compared to recent ballistic experiments performed as a part of this research, and conclusions are drawn based on the findings.

  18. Seasonal zooplankton dynamics in Lake Michigan: disentangling impacts of resource limitation, ecosystem engineering, and predation during a critical ecosystem transition

    Science.gov (United States)

    Vanderploeg, Henry A.; Pothoven, Steven A.; Fahnenstiel, Gary L.; Cavaletto, Joann F.; Liebig, James R.; Stow, Craig Stow; Nalepa, Thomas F.; Madenjian, Charles P.; Bunnell, David B.

    2012-01-01

    We examined seasonal dynamics of zooplankton at an offshore station in Lake Michigan from 1994 to 2003 and 2007 to 2008. This period saw variable weather, declines in planktivorous fish abundance, the introduction and expansion of dreissenid mussels, and a slow decline in total phosphorus concentrations. After the major expansion of mussels into deep water (2007–2008), chlorophyll in spring declined sharply, Secchi depth increased markedly in all seasons, and planktivorous fish biomass declined to record-low levels. Overlaying these dramatic ecosystem-level changes, the zooplankton community exhibited complex seasonal dynamics between 1994–2003 and 2007–2008. Phenology of the zooplankton maximum was affected by onset of thermal stratification, but there was no other discernable effect due to temperature. Interannual variability in zooplankton biomass during 1994 and 2003 was strongly driven by planktivorous fish abundance, particularly age-0 and age-1 alewives. In 2007–2008, there were large decreases in Diacyclops thomasi and Daphnia mendotae possibly caused by food limitation as well as increased predation and indirect negative effects from increases in Bythotrephes longimanus abundance and in foraging efficiency associated with increased light penetration. The Bythotrephes increase was likely driven in part by decreased predation from yearling and older alewife. While there was a major decrease in epilimnetic–metalimnetic herbivorous cladocerans in 2007–2008, there was an increase in large omnivorous and predacious calanoid copepods, especially those in the hypolimnion. Thus, changes to the zooplankton community are the result of cascading, synergistic interactions, including a shift from vertebrate to invertebrate planktivory and mussel ecosystem impacts on light climate and chlorophyll.

  19. Impact of rock materials and biofertilizations on P and K availability for maize (Zea Maize) under calcareous soil conditions

    OpenAIRE

    Abou-el-Seoud, I.I.; Abdel-Megeed, A.

    2012-01-01

    The present work evaluated the synergistic effects of soil fertilization with rock P and K materials and co-inoculation with P and K-dissolving bacteria [PDB (Bacillus megaterium var. phosphaticum) and KDB (Bacillus mucilaginosus and B. subtilis)] on the improvement of P and K uptake, P and K availability and growth of maize plant grown under limited P and K soil conditions (calcareous soil). The experiment was establishment with eight treatments: without rock P and K materials or bacteria in...

  20. An experiment to test advanced materials impacted by intense proton pulses at CERN HiRadMat facility

    CERN Document Server

    Bertarelli, A; Boccone, V; Carra, F; Cerutti, F; Charitonidis, N; Charrondiere, C; Dallocchio, A; Fernandez Carmona, P; Francon, P; Gentini, L; Guinchard, M; Mariani, N; Masi, A; Marques dos Santos, S D; Moyret, P; Peroni, L; Redaelli, S; Scapin, M

    2013-01-01

    Predicting the consequences of highly energetic particle beams impacting protection devices as collimators or high power target stations is a fundamental issue in the design of state-of-the-art facilities for high-energy particle physics. These complex dynamic phenomena can be successfully simulated resorting to highly non-linear numerical tools (Hydrocodes). In order to produce accurate results, however, these codes require reliable material constitutive models that, at the extreme conditions induced by a destructive beam impact, are scarce and often inaccurate. In order to derive or validate such models a comprehensive, first-of-its-kind experiment has been recently carried out at CERN HiRadMat facility: performed tests entailed the controlled impact of intense and energetic proton pulses on a number of specimens made of six different materials. Experimental data were acquired relying on embedded instrumentation (strain gauges, temperature probes and vacuum sensors) and on remote-acquisition devices (laser ...

  1. The economic and community impacts of closing Hanford's N Reactor and nuclear materials production facilities

    Energy Technology Data Exchange (ETDEWEB)

    Scott, M.J.; Belzer, D.B.; Nesse, R.J.; Schultz, R.W.; Stokowski, P.A.; Clark, D.C.

    1987-08-01

    This study discusses the negative economic impact on local cities and counties and the State of Washington of a permanent closure of nuclear materials production at the Hanford Site, located in the southeastern part of the state. The loss of nuclear materials production, the largest and most important of the five Department of Energy (DOE) missions at Hanford, could occur if Hanford's N Reactor is permanently closed and not replaced. The study provides estimates of statewide and local losses in jobs, income, and purchases from the private sector caused by such an event; it forecasts impacts on state and local government finances; and it describes certain local community and social impacts in the Tri-Cities (Richland, Kennewick, and Pasco) and surrounding communities. 33 refs., 8 figs., 22 tabs.

  2. DWPF COAL-CARBON WASTE ACCEPTANCE CRITERIA LIMIT EVALUATION BASED ON EXPERIMENTAL WORK (TANK 48 IMPACT STUDY)

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, D.; Choi, A.

    2010-10-15

    This report summarizes the results of both experimental and modeling studies performed using Sludge Batch 10 (SB10) simulants and FBSR product from Tank 48 simulant testing in order to develop higher levels of coal-carbon that can be managed by DWPF. Once the Fluidized Bed Steam Reforming (FBSR) process starts up for treatment of Tank 48 legacy waste, the FBSR product stream will contribute higher levels of coal-carbon in the sludge batch for processing at DWPF. Coal-carbon is added into the FBSR process as a reductant and some of it will be present in the FBSR product as unreacted coal. The FBSR product will be slurried in water, transferred to Tank Farm and will be combined with sludge and washed to produce the sludge batch that DWPF will process. The FBSR product is high in both water soluble sodium carbonate and unreacted coal-carbon. Most of the sodium carbonate is removed during washing but all of the coal-carbon will remain and become part of the DWPF sludge batch. A paper study was performed earlier to assess the impact of FBSR coal-carbon on the DWPF Chemical Processing Cell (CPC) operation and melter off-gas flammability by combining it with SB10-SB13. The results of the paper study are documented in Ref. 7 and the key findings included that SB10 would be the most difficult batch to process with the FBSR coal present and up to 5,000 mg/kg of coal-carbon could be fed to the melter without exceeding the off-gas flammability safety basis limits. In the present study, a bench-scale demonstration of the DWPF CPC processing was performed using SB10 simulants spiked with varying amounts of coal, and the resulting seven CPC products were fed to the DWPF melter cold cap and off-gas dynamics models to determine the maximum coal that can be processed through the melter without exceeding the off-gas flammability safety basis limits. Based on the results of these experimental and modeling studies, the presence of coal-carbon in the sludge feed to DWPF is found to have

  3. Electrochemically Smart Bimetallic Materials Featuring Group 11 Metals: In-situ Conductive Network Generation and Its Impact on Cell Capacity

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, Esther [Stony Brook Univ., NY (United States)

    2016-11-30

    Our results for this program “Electrochemically smart bimetallic materials featuring Group 11 metals: in-situ conductive matrix generation and its impact on battery capacity, power and reversibility” have been highly successful: 1) we demonstrated material structures which generated in-situ conductive networks through electrochemical activation with increases in conductivity up to 10,000 fold, 2) we pioneered in situ analytical methodology to map the cathodes at several stages of discharge through the use of Energy Dispersive X-ray Diffraction (EDXRD) to elucidate the kinetic dependence of the conductive network formation, and 3) we successfully designed synthetic methodology for direct control of material properties including crystallite size and surface area which showed significant impact on electrochemical behavior.

  4. Bone material strength index as measured by impact microindentation is altered in patients with acromegaly.

    Science.gov (United States)

    Malgo, F; Hamdy, N A T; Rabelink, T J; Kroon, H M; Claessen, K M J A; Pereira, A M; Biermasz, N R; Appelman-Dijkstra, N M

    2017-03-01

    Acromegaly is a rare disease caused by excess growth hormone (GH) production by the pituitary adenoma. The skeletal complications of GH and IGF-1 excess include increased bone turnover, increased cortical bone mass and deteriorated microarchitecture of trabecular bone, associated with a high risk of vertebral fractures in the presence of relatively normal bone mineral density (BMD). We aimed to evaluate tissue-level properties of bone using impact microindentation (IMI) in well-controlled patients with acromegaly aged ≥18 years compared to 44 controls from the outpatient clinic of the Centre for Bone Quality. In this cross-sectional study, bone material strength index (BMSi) was measured in 48 acromegaly patients and 44 controls with impact microindentation using the osteoprobe. Mean age of acromegaly patients (54% male) was 60.2 years (range 37.9-76.5), and 60.5 years (range 39.8-78.6) in controls (50% male). Patients with acromegaly and control patients had comparable BMI (28.2 kg/m(2) ± 4.7 vs 26.6 kg/m(2) ± 4.3, P = 0.087) and comparable BMD at the lumbar spine (1.04 g/cm(2) ± 0.21 vs 1.03 g/cm(2) ± 0.13, P = 0.850) and at the femoral neck (0.84 g/cm(2) ± 0.16 vs 0.80 g/cm(2) ± 0.09, P = 0.246). BMSi was significantly lower in acromegaly patients than that in controls (79.4 ± 0.7 vs 83.2 ± 0.7; P acromegaly after reversal of long-term exposure to pathologically high GH and IGF-1 levels. Our findings also suggest that methods other than DXA should be considered to evaluate bone fragility in patients with acromegaly. © 2017 European Society of Endocrinology.

  5. Understanding Voltage Decay in Lithium-Rich Manganese-Based Layered Cathode Materials by Limiting Cutoff Voltage.

    Science.gov (United States)

    Yang, Jingsong; Xiao, Lifen; He, Wei; Fan, Jiangwei; Chen, Zhongxue; Ai, Xinping; Yang, Hanxi; Cao, Yuliang

    2016-07-27

    The effect of the cutoff voltages on the working voltage decay and cyclability of the lithium-rich manganese-based layered cathode (LRMO) was investigated by electrochemical measurements, electrochemical impedance spectroscopy, ex situ X-ray diffraction, transmission electron microscopy, and energy dispersive spectroscopy line scan technologies. It was found that both lower (2.0 V) and upper (4.8 V) cutoff voltages cause severe voltage decay with cycling due to formation of the spinel phase and migration of the transition metals inside the particles. Appropriate cutoff voltage between 2.8 and 4.4 V can effectively inhibit structural variation as the electrode demonstrates 92% capacity retention and indiscernible working voltage decay over 430 cycles. The results also show that phase transformation not only on high charge voltage but also on low discharge voltage should be addressed to obtain highly stable LRMO materials.

  6. Materials processing strategies for colloidal quantum dot solar cells: advances, present-day limitations, and pathways to improvement

    KAUST Repository

    Carey, Graham H.

    2013-05-13

    Colloidal quantum dot photovoltaic devices have improved from initial, sub-1% solar power conversion efficiency to current record performance of over 7%. Rapid advances in materials processing and device physics have driven this impressive performance progress. The highest-efficiency approaches rely on a fabrication process that starts with nanocrystals in solution, initially capped with long organic molecules. This solution is deposited and the resultant film is treated using a solution containing a second, shorter capping ligand, leading to a cross-linked, non-redispersible, and dense layer. This procedure is repeated, leading to the widely employed layer-by-layer solid-state ligand exchange. We will review the properties and features of this process, and will also discuss innovative pathways to creating even higher-performing films and photovoltaic devices.

  7. Mathematical simulation of the behavior of materials and structural elements under multiple impact loading

    Science.gov (United States)

    Belov, N. N.; Yugov, N. T.; Kopanitsa, D. G.; Tabachenko, A. N.; Afanas'eva, S. A.; Yugov, A. A.; Arkhipov, I. N.

    2010-06-01

    A method of computer simulation is used to investigate the processes of compact cylindrical projectile penetration into steel specimens separated by air gaps during successive group impacts, impact interaction of long steel bars with an explosive screened by a system of spatially separated multilayered screens, and fracture of ferroconcrete columns under repeated longitudinal and transverse impact loading.

  8. Environmental impact and recovery at two dumping sites for dredged material in the North Sea.

    Science.gov (United States)

    Stronkhorst, J; Ariese, F; van Hattum, B; Postma, J F; de Kluijver, M; Den Besten, P J; Bergman, M J N; Daan, R; Murk, A J; Vethaak, A D

    2003-01-01

    The environmental impact and recovery associated with the long and uninterrupted disposal of large volumes of moderately contaminated dredged material from the port of Rotterdam was studied at nearby dumping sites in the North Sea. Observations were made on sediment contamination, ecotoxicity, biomarker responses and benthic community changes shortly after dumping at the 'North' site had ceased and at the start of disposal at the new dumping site 'Northwest'. During the period of dumping, very few benthic invertebrates were found at the North site. Concentrations of cadmium, mercury, polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs) and tributyltin (TBT) in the fine sediment fraction (<63 microm) from this site were 2-3 times higher than at the reference site. In four different bioassays with marine invertebrates the sediments showed no acute toxic effects. In tissue (pyloric caeca) of resident starfish Asterias rubens, residual levels of mercury, zinc, PCBs and dioxin-like activity were never more than twice those at the reference site. Four different biomarkers (DNA integrity, cytochrome P450 content, benzo[a]pyrene hydroxylase activity and acetylcholinesterase inhibition) were used on the starfish tissues, but no significant differences were found between North and the reference site. Minor pathological effects were observed in resident dab Limanda limanda. One year after dumping had ceased at the North site, a significant increase in the species richness and abundance of benthic invertebrates and a concomitant decrease in the fine sediment fraction of the seabed were observed. After 8.2 million m3 of moderately contaminated dredged material had been dumped at the new dumping site Northwest, the species richness and abundance of benthic invertebrates declined over an area extending about 1-2 km eastwards. This correlated with a shift in sediment texture from sand to silt. The contamination of the fine sediment fraction at the Northwest location

  9. Environmental impact and recovery at two dumping sites for dredged material in the North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Stronkhorst, J.; Ariese, F.; Hattum, B. van; Postma, J.F.; Kluijver, M. de; Besten, P.J. den; Bergman, M.J.N.; Daan, R.; Murk, A.J.; Vethaak, A.D

    2003-07-01

    Marine benthic resources near dumping sites are adversely affected by physical disturbances, but a causal link to contaminant damage could not be found. - The environmental impact and recovery associated with the long and uninterrupted disposal of large volumes of moderately contaminated dredged material from the port of Rotterdam was studied at nearby dumping sites in the North Sea. Observations were made on sediment contamination, ecotoxicity, biomarker responses and benthic community changes shortly after dumping at the 'North' site had ceased and at the start of disposal at the new dumping site 'Northwest'. During the period of dumping, very few benthic invertebrates were found at the North site. Concentrations of cadmium, mercury, polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs) and tributyltin (TBT) in the fine sediment fraction (<63 {mu}m) from this site were 2-3 times higher than at the reference site. In four different bioassays with marine invertebrates the sediments showed no acute toxic effects. In tissue (pyloric caeca) of resident starfish Asterias rubens, residual levels of mercury, zinc, PCBs and dioxin-like activity were never more than twice those at the reference site. Four different biomarkers (DNA integrity, cytochrome P450 content, benzo[a]pyrene hydroxylase activity and acetylcholinesterase inhibition) were used on the starfish tissues, but no significant differences were found between North and the reference site. Minor pathological effects were observed in resident dab Limanda limanda. One year after dumping had ceased at the North site, a significant increase in the species richness and abundance of benthic invertebrates and a concomitant decrease in the fine sediment fraction of the seabed were observed. After 8.2 million m{sup 3} of moderately contaminated dredged material had been dumped at the new dumping site Northwest, the species richness and abundance of benthic invertebrates declined over an

  10. The cognitive impact of interactive design features for learning complex materials in medical education.

    Science.gov (United States)

    Song, Hyuksoon S; Pusic, Martin; Nick, Michael W; Sarpel, Umut; Plass, Jan L; Kalet, Adina L

    2014-02-01

    To identify the most effective way for medical students to interact with a browser-based learning module on the symptoms and neurological underpinnings of stroke syndromes, this study manipulated the way in which subjects interacted with a graphical model of the brain and examined the impact of functional changes on learning outcomes. It was hypothesized that behavioral interactions that were behaviorally more engaging and which required deeper consideration of the model would result in heightened cognitive interaction and better learning than those whose manipulation required less deliberate behavioral and cognitive processing. One hundred forty four students were randomly assigned to four conditions whose model controls incorporated features that required different levels of behavioral and cognitive interaction: Movie (low behavioral/low cognitive, n = 40), Slider (high behavioral/low cognitive, n = 36), Click (low behavioral/high cognitive, n = 30), and Drag (high behavioral/high cognitive, n = 38). Analysis of Covariates (ANCOVA) showed that students who received the treatments associated with lower cognitive interactivity (Movie and Slider) performed better on a transfer task than those receiving the module associated with high cognitive interactivity (Click and Drag, partial eta squared = .03). In addition, the students in the high cognitive interactivity conditions spent significantly more time on the stroke locator activity than other conditions (partial eta squared = .36). The results suggest that interaction with controls that were tightly coupled with the model and whose manipulation required deliberate consideration of the model's features may have overtaxed subjects' cognitive resources. Cognitive effort that facilitated manipulation of content, though directed at the model, may have resulted in extraneous cognitive load, impeding subjects in recognizing the deeper, global relationships in the materials. Instructional designers must, therefore, keep in

  11. Investigation of Coupled Processes and Impact of High Temperature Limits in Argillite Rock: FY17 Progress. Predecisional Draft

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Liange; Rutqvist, Jonny; Xu, Hao; Kim, Kunwhi; Voltolini, Marco; Cao, Xiaoyuan

    2017-07-03

    The focus of research within the Spent Fuel and Waste Science and Technology (SFWST) (formerly called Used Fuel Disposal) Campaign is on repository-induced interactions that may affect the key safety characteristics of EBS bentonite and an argillaceous rock. These include thermal-hydrologicalmechanical- chemical (THMC) process interactions that occur as a result of repository construction and waste emplacement. Some of the key questions addressed in this report include the development of fracturing in the excavation damaged zone (EDZ) and THMC effects on the near-field argillaceous rock and buffer materials and petrophysical characteristics, particularly the impacts of temperature rise caused by waste heat. This report documents the following research activities. Section 2 presents THM model developments and validation, including modeling of underground heater experiments at Mont Terri and Bure underground research laboratories (URLs). The heater experiments modeled are the Mont Terri FE (Full-scale Emplacement) Experiment, conducted as part of the Mont Terri Project, and the TED in heater test conducted in Callovo-Oxfordian claystone (COx) at the Meuse/Haute-Marne (MHM) underground research laboratory in France. The modeling of the TED heater test is one of the Tasks of the DEvelopment of COupled Models and their VAlidation against EXperiments (DECOVALEX)-2019 project. Section 3 presents the development and application of thermal-hydrological-mechanical-chemical (THMC) modeling to evaluate EBS bentonite and argillite rock responses under different temperatures (100 °C and 200 °C). Model results are presented to help to understand the impact of high temperatures on the properties and behavior of bentonite and argillite rock. Eventually the process model will support a robust GDSA model for repository performance assessments. Section 4 presents coupled THMC modeling for an in situ test conducted at Grimsel underground laboratory in Switzerland in the Full

  12. Comparative Case Study as Social Impact Assessment: Possibilities and Limitations for Anticipating Social Change in the Far North

    Science.gov (United States)

    Asselin, Jodie; Parkins, John R.

    2009-01-01

    Social impact assessment (SIA) is increasingly an accepted component of environmental impact assessment and project evaluation throughout North America. Tools and methodologies utilized to conduct such assessments vary greatly and continue to evolve with time and experience. This paper follows the evolution of case study methods in social impact…

  13. The impact of self healing materials on telecommunication: towards a concrete aircraft?

    NARCIS (Netherlands)

    Schmets, A.J.M.

    2006-01-01

    The use of a material for a specific application is governed by considerations on the expected conditions during its lifetime. For aerospace applications for instance, lightness, reliability and thermal stability ofthe material are of major importance. No material will ever possess all the desired

  14. Impact of second line limiting amino acids’ deficiency in broilers fed low protein diets with rapeseed meal and de-oiled rice bran

    Directory of Open Access Journals (Sweden)

    C. Basavanta Kumar

    2015-03-01

    Full Text Available Aim: To study the impact of deficiency of second line limiting amino acids (SLAA; valine, isoleucine and tryptophan on the production performance and carcass characteristics of commercial broilers. Materials and Methods: A control (T1 corn-soy diet was formulated to contain all essential AA on standardized ileal digestible basis; While in T2-a ‘moderate SLAA deficit’ diet was formulated by replacement of soybean meal with 6% rapeseed meal and T3-a ‘high SLAA deficit’ diet was formulated by replacement of soybean meal with 6% de-oiled rice bran. Each of these treatments was allotted to six replicates of ten chicks each. During the 42 days experimental period, growth performance, carcass parameters and intake of metabolizable energy (ME, crude protein (CP and AA were studied. Results: The cumulative body weight gain, feed conversion ratio, carcass cut weights and yields of carcass, breast and thighs were decreased (p<0.05 in T3 compared to T1. The absolute intake of ME, lysine, methionine + cysteine and threonine were not affected while intake of CP and all SLAA were reduced in SLAA deficit diets. The relative intake of ME, lysine, methionine + cysteine, threonine and SLAA reduced in T3 in comparison to T1. The relative weights of internal organs were not affected by treatments while the abdominal fat percentage was increased linearly to the magnitude of SLAA deficiency. Conclusion: The deficiency of SLAA decreased performance, carcass yields and impaired utilization of ME, CP and AA linearly to the magnitude of the deficiency.

  15. Impact of contact lens materials on multipurpose contact lens solution disinfection activity against Fusarium solani.

    Science.gov (United States)

    Clavet, Charles R; Chaput, Maria P; Silverman, Matthew D; Striplin, Megan; Shoff, Megan E; Lucas, Anne D; Hitchins, Victoria M; Eydelman, Malvina B

    2012-11-01

    To investigate the effects of eight different soft contact lenses on disinfection efficacy of a multipurpose solution (MPS) containing polyhexamethylene biguanide (PHMB) against Fusarium solani. Six silicone hydrogel lenses (galyfilcon A, senofilcon A, comfilcon A, enfilcon A, balafilcon A, and lotrifilcon B) and two conventional hydrogel lenses (polymacon and etafilcon A) were placed in polypropylene lens cases filled with MPS containing 0.0001% PHMB and soaked for 6, 12, 24, 72, and 168 hours. After each interval, depleted MPS from lens cases were removed and assayed for activity against F. solani according to International Organization for Standardization (ISO) 14729 stand-alone procedure. A portion was aliquoted for chemical analysis. Soaking etafilcon A, balafilcon A, and polymacon lenses for 6 hours reduced the concentration of PHMB in MPS by more than half the stated labeled concentration, with concentrations below the limit of detection for etafilcon A-depleted and balafilcon A-depleted solutions after 12 and 72 hours of soaking, respectively. Except for comfilcon A-depleted solutions, all others failed to consistently obtain one log reduction of F. solani. The solutions soaked with etafilcon A, balafilcon A, and polymacon lenses for 24 hours or more lost all or almost all fungicidal activity against F. solani. Over time, the disinfectant uptake by some lenses can significantly reduce the PHMB concentration and the fungicidal activity of the MPS against F. solani. Current ISO methodology does not address the reduction in microbiocidal efficacy when lenses are soaked in MPS. The ISO committee should consider adding "soaking experiments" to quantify the effect that contact lens materials have on the performance of MPSs.

  16. Feasibility Study of Sensor Aided Impact Acoustic Sorting of Plastic Materials from End-of-Life Vehicles (ELVs

    Directory of Open Access Journals (Sweden)

    Jiu Huang

    2015-12-01

    Full Text Available The purpose of this feasibility research was to study a novel sensor based separation method for recycling of plastic materials from end-of-life vehicles (ELVs by using eigen-frequency response of impact acoustic emission. In this research three kinds of commonly used plastics, polypropylene (PP, acrylonitrile-butadiene-styrene (ABS, and styrene-maleic-anhydride (SMA sampled from end-of-life vehicles, were researched. Almost all the crushed plastic scraps had a flake structure, theoretically their impact response behaviors were determined by their diameters and thicknesses. The equivalent diameters of the scraps were characterized by fine sieving and their thicknesses were measured online by a 3D laser triangulation sensor above the conveying path. Following this the scraps were free dropped one-by-one to impact with an impact passive body on which impact acoustic emission (AE signals were generated and acquired by an acoustic pickup sensor. Thirdly, the AE signals which carried eigen-frequency response features were processed and characterized. Results demonstrated that the scraps with diameters < 8 mm were too weak for the actual devices to process; the scraps with diameter from 8–13 mm still generated quite a lot of AE signals of inadequate intensity. Finally the general characterization and recognition yields were 64.6%, 61.7%, and 63.9% of PP, ABS, and SMA in mass, respectively of tested materials.

  17. Materials

    Science.gov (United States)

    Glaessgen, Edward H.; Schoeppner, Gregory A.

    2006-01-01

    NASA Langley Research Center has successfully developed an electron beam freeform fabrication (EBF3) process, a rapid metal deposition process that works efficiently with a variety of weldable alloys. The EBF3 process can be used to build a complex, unitized part in a layer-additive fashion, although the more immediate payoff is for use as a manufacturing process for adding details to components fabricated from simplified castings and forgings or plate products. The EBF3 process produces structural metallic parts with strengths comparable to that of wrought product forms and has been demonstrated on aluminum, titanium, and nickel-based alloys to date. The EBF3 process introduces metal wire feedstock into a molten pool that is created and sustained using a focused electron beam in a vacuum environment. Operation in a vacuum ensures a clean process environment and eliminates the need for a consumable shield gas. Advanced metal manufacturing methods such as EBF3 are being explored for fabrication and repair of aerospace structures, offering potential for improvements in cost, weight, and performance to enhance mission success for aircraft, launch vehicles, and spacecraft. Near-term applications of the EBF3 process are most likely to be implemented for cost reduction and lead time reduction through addition of details onto simplified preforms (casting or forging). This is particularly attractive for components with protruding details that would require a significantly large volume of material to be machined away from an oversized forging, offering significant reductions to the buy-to-fly ratio. Future far-term applications promise improved structural efficiency through reduced weight and improved performance by exploiting the layer-additive nature of the EBF3 process to fabricate tailored unitized structures with functionally graded microstructures and compositions.

  18. Characterization of impact materials around Barringer Meteor Crater by micro-PIXE and micro-SRXRF techniques

    Energy Technology Data Exchange (ETDEWEB)

    Uzonyi, I. E-mail: uzonyi@atomki.hu; Szoeor, Gy.; Rozsa, P.; Vekemans, B.; Vincze, L.; Adams, F.; Drakopoulos, M.; Somogyi, A.; Kiss, A.Z

    2004-06-01

    A combined micro-PIXE and micro-SRXRF method has been tested successfully for the characterization of impact materials collected at the well-known Barringer Meteor Crater. The micro-PIXE technique proved to be sensitive in the Z{<=}28 atomic number region while the micro-SRXRF above Fe especially for the siderophile elements. Quantitative analysis has become available for about 40 elements by these complementary methods providing new perspectives for the interpretation of the formation mechanism of impact metamorphosed objects.

  19. Inverse Limits

    CERN Document Server

    Ingram, WT

    2012-01-01

    Inverse limits provide a powerful tool for constructing complicated spaces from simple ones. They also turn the study of a dynamical system consisting of a space and a self-map into a study of a (likely more complicated) space and a self-homeomorphism. In four chapters along with an appendix containing background material the authors develop the theory of inverse limits. The book begins with an introduction through inverse limits on [0,1] before moving to a general treatment of the subject. Special topics in continuum theory complete the book. Although it is not a book on dynamics, the influen

  20. Interior Head Impact Protective Components and Materials for Use in US Army Vehicles

    Science.gov (United States)

    2015-08-01

    project is to reduce potential head impact related mounted crew injuries and deaths which may occur during underbody blast, crash and rollover events...effort identified solutions which may potentially meet the needs of the Army to reduce head impact related injuries which may occur during crash ...effort centers on reducing potential head impact related injuries and deaths of mounted crew which may occur during blast, crash and rollover events

  1. A Study on the Mechanical Properties and Impact-Induced Initiation Characteristics of Brittle PTFE/Al/W Reactive Materials.

    Science.gov (United States)

    Ge, Chao; Maimaitituersun, Wubuliaisan; Dong, Yongxiang; Tian, Chao

    2017-04-26

    Polytetrafluoroethylene/aluminum/tungsten (PTFE/Al/W) reactive materials of three different component mass ratios (73.5/26.5/0, 68.8/24.2/7 and 63.6/22.4/14) were studied in this research. Different from the PTFE/Al/W composites published elsewhere, the materials in our research were fabricated under a much lower sintering temperature and for a much shorter duration to achieve a brittle property, which aims to provide more sufficient energy release upon impact. Quasi-static compression tests, dynamic compression tests at room and elevated temperatures, and drop weight tests were conducted to evaluate the mechanical and impact-induced initiation characteristics of the materials. The materials before and after compression tests were observed by a scanning electron microscope to relate the mesoscale structural characteristics to their macro properties. All the three types of materials fail at very low strains during both quasi-static and dynamic compression. The stress-strain curves for quasi-static tests show obvious deviations while that for the dynamic tests consist of only linear-elastic and failure stages typically. The materials were also found to exhibit thermal softening at elevated temperatures and were strain-rate sensitive during dynamic tests, which were compared using dynamic increase factors (DIFs). Drop-weight test results show that the impact-initiation sensitivity increases with the increase of W content due to the brittle mechanical property. The high-speed video sequences and recovered sample residues of the drop-weight tests show that the reaction is initiated at two opposite positions near the edges of the samples, where the shear force concentrates the most intensively, indicating a shear-induced initiation mechanism.

  2. Impact of Materials on Conservation of the Built Environment: Case Study of Historic Mosques in Mosul Old City

    Directory of Open Access Journals (Sweden)

    Muna Hanim Abdul Samad

    2012-01-01

    Full Text Available Conservation of the built environment through reusing historic buildings maximizes the use of existing materials. The research question is how to retain the integrity of historic mosques through using sustainable material? The main purpose of this study is to investigate the impact of materials on conservation of historic mosques in old Mosul city with sustaining the integrity of the mosques. The study applies qualitative method of analysis. The method of collecting data is by making direct observation. The techniques for collecting data are by writing descriptions and making an inventory of the variety and arrangement of the materials used in the historic mosques. The research uses open coding to analyse the data by identification of emerging themes from the raw data. The goal is to create descriptive and multi-dimensional categories and build a conceptual model from the categories, which are grouped. This study highlights the themes of materials used in historic mosques in Mosul old city and show that the integrity of mosques affected by the materials, which were used in these mosques. The research showed that the elements that the damages occurred in as a result of the use of inadequate materials which used in such elements. The research recommends that experience is vital in conversation of the historical buildings and require to performed identification, evaluation, registration and treatment activities. In some cases, additional areas or levels of expertise may be needed, depending on the complexity of the task and the nature of the historic building involved.

  3. An upper limit of Cr-doping level to Retain Zero-strain Characteristics of Li4Ti5O12 Anode Material for Li-ion Batteries

    Science.gov (United States)

    Song, Hannah; Jeong, Tae-Gyung; Yun, Su-Won; Lee, Eun-Kyung; Park, Shin-Ae; Kim, Yong-Tae

    2017-01-01

    Since Li4Ti5O12 as a promising anode material in lithium-ion batteries (LIBs) has a poor rate performance due to low electronic conductivity, a doping of Li4Ti5O12 with heterogeneous atoms has been considered to overcome this problem. Herein, we report that there is an upper limit of doping level to maintain the zero strain characteristics of Li4Ti5O12 lattice during charge/discharge process. By using synchrotron studies, it was revealed that the Li+ diffusivity was maximized at a certain doping level for which the conductivity was markedly increased with maintaining the zero strain characteristics. However, with more doses of dopants over the upper limit, the lattice shrank and therefore the Li+ diffusivity decreased, although the electronic conductivity was further increased in comparison with the optimal doping level. PMID:28233818

  4. The impact of joint range of motion limitations on health-related quality of life in patients with haemophilia A: a prospective study.

    Science.gov (United States)

    Chen, C M; Huang, K C; Chen, C C; Huang, S U; Huang, C E; Chen, Y Y; Hsu, S L

    2015-05-01

    In patients with haemophilia A, repeated occurrences of haemarthrosis and synovitis lead to limitations in range of motion (ROM) of major joints. However, the effect of limitations in joint ROM on health-related quality of life (HRQOL) in these patients has not been studied previously. The aim of this study was to assess the impact of ROM limitations of 10 major joints (bilateral shoulders, elbows, hips, knees and ankles), combined with other possibly influential factors, on HRQOL in patients with haemophilia A. The ROM limitations in 13 movements and pain intensity of the 10 major joints were measured. The socio-demographic and clinical data were recorded. Short-Form 36 was used as the HRQOL measurement. Eighteen patients (mean age: 36.9 years) were included. Hip ROM limitations, knee ROM limitations and hip pain intensity predicted physical functioning scale (P < 0.001; adjusted R2 = 0.553). Shoulder ROM limitations and age predicted role limitation were due to emotional problems scale (P < 0.001; adjusted R2 = 0.373). Elbow ROM limitations and haemophilia severity predicted mental health scale (P = 0.001; adjusted R2 = 0.320). Hip ROM limitations predicted social functioning scale (P = 0.041; adjusted R2 = 0.091). Educational level and elbow ROM limitations predicted vitality scale (P < 0.001; adjusted R2 = 0.416). The ROM limitations of hip, knee, shoulder and elbow could be predictors for HRQOL in patients with haemophilia A. Improving ROM of major joints could be an appropriate treatment strategy to enhance HRQOL in these patients.

  5. Knowledge platform for calculating climate impact from construction and building materials. Literature study; Kunnskapsplattform for beregning av klimabelastning fra bygg og byggematerialer. Litteraturstudie

    Energy Technology Data Exchange (ETDEWEB)

    Roenning, Anne; Lyng, Kari-Anne; Vold, Mie

    2011-07-01

    Greenhouse gas emissions from building linked today to a large extent to the energy consumption during the operating period. Through increasingly stringent energy requirements and other changes, the energy consumption for the operation could go down over time. This means in this case that the energy required to produce, transport and set up the building, to a greater extent can be relatively more important in a life-cycle analysis. KRD in that regard ha given Oestfoldforskning the commission to conduct a literature study that will provide an overview and assessment of the literature / research papers describing various building materials climate impact and how this translates into a lifetime (LCA - Life Cycle Assessment), and thus describe the knowledge platform these analyzes are based in. It also means a description of the factors that affect the climate and the environment, including the stages of life that are important. Literature study is conducted by searching scientific databases (Springer Link, Science Direct, Google Scholar, Norwegian EPD database of declarations). The literature search is limited to studies that are based on LCA as a methodology for calculating the climate impacts associated with the construction and building materials. Based on the review of literature is also undertaken an analysis focusing on explaining the methodological platform between the studies are based on, in order to explain why the results differ and / or may not be comparable.(eb)

  6. Computation of single solid particle impact on the target of ductile material to study the rebound characteristics of particle

    Science.gov (United States)

    Yeuan, Jian Jong

    1992-04-01

    The objective of this research work is to simulate a single solid particle impact on a solid target using elastic-plastic theory. The entire impact process involves the adhesion, deformation and rebound process interacting between the solid particle and the target. The governing equations for two dimensional elastic-plastic flow are formulated in Lagrangian coordinates. The equation of state in the elastic region is the time rate of change of Hooke's law. In the plastic region, the experimental Hugoniot equation of state and the yield condition of R. von Mises are used. The effect of strain rate on the material strength is considered using a semi-empirical formulation. The developed computer program employs a finite volume numerical technique and two step explicit MacCormack scheme, which is second order accurate in time, allowing finer resolution of the transient phenomena of impact. Results are presented for a hard tool steel particle impacting on a mild steel target at impact angles of 20 to 90 degrees. The computational results are compared with experimental data for a range of impacting velocities up to 350 m/sec. The effect of particle in the particle rebound characteristics are also investigated. In the previous research, the particle rebound characteristics obtained from experiments were correlated and used in the calculation of particle trajectories in turbomachinery flows. Here, the computational results are applied to predict solid particle trajectories in a highly loaded axial flow turbine.

  7. A health impact assessment of a proposed bill to decrease speed limits on local roads in Massachusetts (U.S.A.).

    Science.gov (United States)

    James, Peter; Ito, Kate; Banay, Rachel F; Buonocore, Jonathan J; Wood, Benjamin; Arcaya, Mariana C

    2014-01-01

    Decreasing traffic speeds increases the amount of time drivers have to react to road hazards, potentially averting collisions, and makes crashes that do happen less severe. Boston's regional planning agency, the Metropolitan Area Planning Council (MAPC), in partnership with the Massachusetts Department of Public Health (MDPH), conducted a Health Impact Assessment (HIA) that examined the potential health impacts of a proposed bill in the state legislature to lower the default speed limits on local roads from 30 miles per hour (mph) to 25 mph. The aim was to reduce vehicle speeds on local roads to a limit that is safer for pedestrians, cyclists, and children. The passage of this proposed legislation could have had far-reaching and potentially important public health impacts. Lower default speed limits may prevent around 18 fatalities and 1200 serious injuries to motorists, cyclists and pedestrians each year, as well as promote active transportation by making local roads feel more hospitable to cyclists and pedestrians. While a lower speed limit would increase congestion and slightly worsen air quality, the benefits outweigh the costs from both a health and economic perspective and would save the state approximately $62 million annually from prevented fatalities and injuries.

  8. Investigation of impact materials around Barringer Meteor Crater by SEM-EDX and micro-PIXE techniques

    Energy Technology Data Exchange (ETDEWEB)

    Uzonyi, I. [Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), Department of Electrostatic Accelerators, H-4026 Debrecen, Bem ter 18/C (Hungary)], E-mail: uzonyi@atomki.hu; Szoeor, Gy.; Rozsa, P. [Department of Mineralogy and Geology, University of Debrecen, H-4010 Debrecen, Egyetem ter 1 (Hungary); Pelicon, P.; Simcic, J. [Jozef Stefan Institute, Microanalytical Center, Jamova 39, P.P. 3000, SI-1001 Ljubljana (Slovenia); Cserhati, C.; Daroczi, L. [Department of Solid State Physics, University of Debrecen, H-4032 Debrecen, Bem ter 18/b (Hungary); Kiss, A.Z. [Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), Department of Electrostatic Accelerators, H-4026 Debrecen, Bem ter 18/C (Hungary)

    2009-06-15

    Impact materials collected at the Barringer Meteor Crater have been characterized by SEM-EDX and micro-PIXE techniques. Fine textural and true elemental images were created. As a main feature silica-bearing shell and an S-Fe-Ni-Cu core could be distinguished. Three different types of S-Fe-Ni-Cu systems were identified such as chalcopyrite, pentlandite and pyrrhotite.

  9. Feasibility Study of Sensor Aided Impact Acoustic Sorting of Plastic Materials from End-of-Life Vehicles (ELVs)

    OpenAIRE

    Jiu Huang; Zhengfu Bian; Shaogang Lei

    2015-01-01

    The purpose of this feasibility research was to study a novel sensor based separation method for recycling of plastic materials from end-of-life vehicles (ELVs) by using eigen-frequency response of impact acoustic emission. In this research three kinds of commonly used plastics, polypropylene (PP), acrylonitrile-butadiene-styrene (ABS), and styrene-maleic-anhydride (SMA) sampled from end-of-life vehicles, were researched. Almost all the crushed plastic scraps had a flake structure, theoretica...

  10. Material removal mechanism during porous silica cluster impact on crystal silicon substrate studied by molecular dynamics simulation

    Energy Technology Data Exchange (ETDEWEB)

    Chen Ruling, E-mail: chenrl04@mails.tsinghua.edu.cn [Research Center of Nano-science and Nano-technology, Shanghai University, Shanghai 200444 (China); Jiang Ranran; Lei Hong; Liang Min [Research Center of Nano-science and Nano-technology, Shanghai University, Shanghai 200444 (China)

    2013-01-01

    Highlights: Black-Right-Pointing-Pointer The impact of the porous silica clusters on a silicon substrate was studied by MD. Black-Right-Pointing-Pointer The porous cluster shows high MRR and low surface damage at an optimal pore size. Black-Right-Pointing-Pointer The high MRR is due to the combined effects of plough, adhesion and permeation. Black-Right-Pointing-Pointer The low surface damage is due to the decreasing of the penetration depth. Black-Right-Pointing-Pointer Enlarged contact area is more effective than increased penetration to enhance MRR. - Abstract: Molecular dynamics (MD) simulation is applied in analyzing the material removal mechanism of silicon substrate under the impact of large porous silica cluster with different pore diameters. With the increasing of the pore diameter of the porous cluster, the number of the atoms removed from the impact silicon surface will firstly increase and then decrease until the cluster is adhered to the substrate, which is due to the combinational effects of plough of the cluster, adhesion between the cluster and the substrate, and permeation of the substrate atoms through the pore of the cluster. And adhesion is the most significant one among these three effects. Meanwhile, the damage of the impact substrate will become weaker due to the decreasing of the penetration depth with the increasing of the pore diameter. In addition, it is found that the effect of an enlarged real contact area between the cluster and the substrate is more significant than that of deeper penetration of the cluster in order to enhance the material removal rate (MRR) during the impact process. These findings are instructive in optimizing the process parameters to obtain lower surface roughness and higher material removal rate during the chemical mechanical polishing process.

  11. Impact of back-contact materials on performance and stability of cadmium sulfide/cadmium telluride solar cells

    Science.gov (United States)

    Demtsu, Samuel H.

    Thin-film CdTe based solar cells are one of the leading contenders for providing lowcost and pollution-free energy, The formation of a stable, low resistance, non-rectifying contact to p-CdTe thin-film is one of the major and critical challenges associated with this technology in the fabrication of efficient and stable solar cells. The premise of this thesis is a systematic study of the impact of back-contact materials on the initial performance and the degradation of CdS/CdTe solar cells. Two different back-contact structures that incorporate Cu as a key element are investigated in this study: (a) Cu1.4Te:HgTe-doped graphite and (b) evaporated-Cu back contacts. The effect of Cu inclusion is not limited to the back-contact layer where it is deposited. Cu is a known fast diffuser in p-CdTe, and therefore, a significant amount of Cu reaches both the CdTe and US layers. Hence, the effect of the presence of Cu on the individual layers: back-contact, the absorber (CdTe), and the window (CdS) layers is discussed respectively. The effect of different metals used to form the current-carrying electrode following the Cu layer is also evaluated. Devices are studied through current-voltage (JV) measurements at different temperatures and intensities, quantum efficiency (QE) measurements under light and voltage bias, capacitance-voltage (CV), drive-level-capacitance-profiling (DLCP), and time-resolved photoluminescence (TRPL) measurements. Numerical simulation is also used to reproduce and explain some of the experimental results. In devices made without Cu, a current-limiting effect, rollover (distortion) in the current-voltage characteristic, was observed. With the inclusion of a small amount of Cu (5-nm), however, the distortion disappeared, and higher FF was obtained. The performance of these devices was comparable to devices made with the standard Cu-doped graphite paste contacts when the same CdTe absorber is used. Small amount of Cu (5-20 nm) partially diffused into the

  12. The impact of self-perceived limitations, stigma and sense of coherence on quality of life in multiple sclerosis patients: results of a cross-sectional study.

    Science.gov (United States)

    Broersma, Feddrik; Oeseburg, Barth; Dijkstra, Jacob; Wynia, Klaske

    2017-09-01

    To examine the impact of perceived limitations, stigma and sense of coherence on quality of life in multiple sclerosis patients. Cross-sectional survey. Department of Neurology, University Medical Center Groningen, the Netherlands. Multiple sclerosis patients. World Health Organization Quality of Life - abbreviated version, Stigma Scale for Chronic Illness, Sense of Coherence Scale, background and disease-related questions. In total, 185 patients (61% response rate) participated in the study with moderate to severe limitations. Stigma was highly prevalent but low in severity. Patients with a higher sense of coherence experienced a lower level of limitations ( B = -0.063, P sense of coherence experienced better quality of life (physical health B = 0.059, P life (physical health B = -0.364, P life (self-stigma: physical health B = -0.073, P sense of coherence experienced better quality of life. Patients with a higher sense of coherence experienced a lower level of limitations and less stigma.

  13. A pulse-shaping technique to investigate the behaviour of brittle materials subjected to plate-impact tests

    Science.gov (United States)

    Forquin, Pascal; Zinszner, Jean-Luc

    2017-01-01

    Owing to their significant hardness and compressive strengths, ceramic materials are widely employed for use with protective systems subjected to high-velocity impact loadings. Therefore, their mechanical behaviour along with damage mechanisms need to be significantly investigated as a function of loading rates. However, the classical plate-impact testing procedures produce shock loadings in the brittle sample material which cause unrealistic levels of loading rates. Additionally, high-pulsed power techniques and/or functionally graded materials used as flyer plates to smooth the loading pulse remain costly, and are generally difficult to implement. In this study, a shockless plate-impact technique based on the use of either a wavy-machined flyer plate or buffer plate that can be produced by chip-forming is proposed. A series of numerical simulations using an explicit transient dynamic finite-element code have been performed to design and validate the experimental testing configuration. The calculations, conducted in two-dimensional (2D) plane-strain or in 2D axisymmetric modes, prove that the `wavy' contact surface will produce a pulse-shaping effect, whereas the buffer plate will produce a homogenizing effect of the stress field along the transverse direction of the sample. In addition, `wavy-shape' geometries of different sizes provide an easy way to change the level of loading rate and rise time in an experimentally tested ceramic specimen. Finally, when a shockless compression loading method is applied to the sample, a Lagrangian analysis of data is made possible by considering an assemblage of ceramic plates of different thicknesses in the target, so the axial stress-strain response of the brittle sample material can be provided. This article is part of the themed issue 'Experimental testing and modelling of brittle materials at high strain rates'.

  14. Life Cycle Assessment of Common Plastic Packaging for Reducing Environmental Impact and Material Consumption

    Directory of Open Access Journals (Sweden)

    Visvaldas Varžinskas

    2009-12-01

    the Faculty of Design and Technologies, Kaunas University of Technology, together with packaging and environmental protection specialists of the University, and in cooperation with the Department of Printed Publications and Packaging of the Ukrainian Print Academy. The present paper analyses certain basic findings of the study on the possibilities of improving the ecological level of packaging within the framework of the project. It is stated that appropriate investigation of packaging, its production and application has to be performed in order to prove that the packaging was produced in compliance with preventive and other principles; this investigation is related to a wide variety of package testing, some of which has not yet got methodology acknowledged at a sufficient level (the EU or groups of countries. Therefore, one of the research directions in the above mentioned project, discussed in the present paper, is related to developing a single system, recognized throughout the EU, which would enable researchers to perform the required tests confirming the packaging quality compliance with the environmental requirements. The paper analyzes the EU prevention regulations for reducing the amount of raw material and the system of checking the realization of the requirements based on identification of critical areas, aimed at reaching the lowest possible package weight and/or volume, consequently, the minimum waste amount, without increasing the amount of faulty products and product waste. The paper presents the findings of the research obtained in assessing the life cycle, when applying the Ecoindicator'99 qualitative analysis, concerning the impact of common plastic packages and processes on the environment during manufacturing, usage and disposal. Compression test results of common type plastic packaging construction are presented, which allow us to assess the impact of the package shape and construction upon the packaging reliability and minimization of its mass.

  15. Impact of Chlorine dioxide Gas on the Barrier Properties of Polymeric Packaging Materials

    Science.gov (United States)

    One important criterion of polymeric material selection and packaging design for fresh produce is choosing the material with suitable ratio of carbon dioxide and oxygen permabilities (PCO2/P O2), to the respiratory proportion of the targeted produce. The ratio of [O2] and [CO2] in the head space var...

  16. 75 FR 69138 - Environmental Assessment and Finding of No Significant Impact Related to Exemption of Material...

    Science.gov (United States)

    2010-11-10

    ... shielding, building materials, and soil debris from Unit 3. The waste would be transported by truck from...). The engineered features include an engineered cover, liners and leachate monitoring systems. Because... material, gravel and other metal, wood and soil debris generated during dismantlement activities located...

  17. Measurement of the effect of playground surface materials on hand impact forces during upper limb fall arrests.

    Science.gov (United States)

    Choi, Woochol J; Kaur, Harjinder; Robinovitch, Stephen N

    2014-04-01

    Distal radius fractures are common on playgrounds. Yet current guidelines for the selection of playground surface materials are based only on protection against fall-related head injuries. We conducted "torso release" experiments to determine how common playground surface materials affect impact force applied to the hand during upper limb fall arrests. Trials were acquired for falls onto a rigid surface, and onto five common playground surface materials: engineered wood fiber, gravel, mulch, rubber tile, and sand. Measures were acquired for arm angles of 20 and 40 degrees from the vertical. Playground surface materials influenced the peak resultant and vertical force (Pforce (P=.159). When compared with the rigid condition, peak resultant force was reduced 17% by sand (from 1039 to 864 N), 16% by gravel, 7% by mulch, 5% by engineered wood fiber, and 2% by rubber tile. The best performing surface provided only a 17% reduction in peak resultant force. These results help to explain the lack of convincing evidence from clinical studies on the effectiveness of playground surface materials in preventing distal radius fractures during playground falls, and highlight the need to develop playground surface materials that provide improved protection against these injuries.

  18. Computational Modeling to Limit the Impact Displays and Indicator Lights Have on Habitable Volume Operational Lighting Constraints

    Science.gov (United States)

    Clark, T. A.; Salazar, G. A.; Brainard, G. C.; Litaker, H. L.; Hanifin, J.; Schwing, B. M.

    2016-01-01

    Even with no ambient lighting system "on", the International Space Station glows at night. The glow is caused by indicator lamps and displays that are not included with the specification of the ambient lighting system. How does this impact efforts to improve the astronaut's lighting environment to promote more effective sleep patterns? Do the extra indicators and displays add enough light to change the spectrum of light the crew sees during the day as well? If spacecraft environments are specifically engineered to have an ambient lighting system that emits a spectrum promoting a healthy circadian response, is there a way control the impact? The goal of this project is to investigate how additional light sources, such as displays and indicators change the effective light spectrum of the architectural lighting system and how impacts can be mitigated.

  19. Assessment of the effects of the Japanese shift to lead-free solders and its impact on material substitution and environmental emissions by a dynamic material flow analysis.

    Science.gov (United States)

    Fuse, Masaaki; Tsunemi, Kiyotaka

    2012-11-01

    Lead-free electronics has been extensively studied, whereas their adoption by society and their impact on material substitution and environmental emissions are not well understood. Through a material flow analysis (MFA), this paper explores the life cycle flows for solder-containing metals in Japan, which leads the world in the shift to lead-free solders in electronics. The results indicate that the shift has been progressing rapidly for a decade, and that substitutes for lead in solders, which include silver and copper, are still in the early life cycle stages. The results also show, however, that such substitution slows down during the late life cycle stages owing to long electronic product lifespans. This deceleration of material substitution in the solder life cycle may not only preclude a reduction in lead emissions to air but also accelerate an increase in silver emissions to air and water. As an effective measure against ongoing lead emissions, our scenario analysis suggests an aggressive recycling program for printed circuit boards that utilizes an existing recycling scheme. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Velocities and relative amount of material ejected from Comet 9P/Tempel 1 after the Deep Impact collision

    CERN Document Server

    Ipatov, Sergei I

    2008-01-01

    Time variations of velocities and relative amount of material ejected from Comet 9P/Tempel 1 are studied based on analysis of the images made by Deep Impact (DI) cameras during the first 13 minutes after the collision of the DI impactor with the comet. The rate of production of observed ejected material and velocities considered correspond mainly to small (with diameter d1 s can be considered to be proportional to te^{-0.75} or te^{-0.7 }, but the decrease of velocity could differ from this exponential dependence. Comparison of the observed DI ejection with theoretical models testifies in favor of a model close to gravity-dominated cratering, i.e. in favor of greater amounts of ejected material and greater size of a crater.

  1. Femtosecond laser ablation properties of transparent materials: impact of the laser process parameters on the machining throughput

    Science.gov (United States)

    Matylitsky, V. V.; Hendricks, F.; Aus der Au, J.

    2013-03-01

    High average power, high repetition rate femtosecond lasers with μJ pulse energies are increasingly used for bio-medical and material processing applications. With the introduction of femtosecond laser systems such as the SpiritTM platform developed by High Q Lasers and Spectra-Physics, micro-processing of solid targets with femtosecond laser pulses have obtained new perspectives for industrial applications [1]. The unique advantage of material processing with subpicosecond lasers is efficient, fast and localized energy deposition, which leads to high ablation efficiency and accuracy in nearly all kinds of solid materials. The study on the impact of the laser processing parameters on the removal rate for transparent substrate using femtosecond laser pulses will be presented. In particular, examples of micro-processing of poly-L-lactic acid (PLLA) - bio-degradable polyester and XensationTM glass (Schott) machined with SpiritTM ultrafast laser will be shown.

  2. Influence of Constituent Materials on the Impact Toughness and Fracture Mechanisms of Hot-Roll-Bonded Aluminum Multilayer Laminates

    Science.gov (United States)

    Cepeda-Jiménez, C. M.; Hidalgo, P.; Pozuelo, M.; Ruano, O. A.; Carreño, F.

    2010-01-01

    Two aluminum multilayer laminates have been processed by hot roll bonding following similar processing paths. The first one is constituted by alternated Al 2024 and Al 1050 layers (ALH19) and the second one by alternated Al 7075 and Al 1050 layers (ADH19). The influence of the constituent materials in the multilayer laminates both during the processing at high temperature and during the subsequent mechanical characterization has been analyzed. The mechanical behavior of the as-received materials at the processing conditions has been characterized by hot torsion. Multilayer laminates have been tested at room temperature under impact Charpy tests, three-point bend tests, and shear tests on the interfaces. The relative toughness increase compared to the constituent materials was much higher for the ADH19 laminate based on the high-strength Al 7075 alloy than for the ALH19 laminate. This is attributed to the different fracture mechanism.

  3. Assessment of impact of construction materials on the ecological safety of home

    Directory of Open Access Journals (Sweden)

    Zhigulina Anna

    2017-01-01

    Full Text Available The article deals with the problems of creating environmentally friendly aerial environment within residential premises. The main sources causing air pollution of urban housing are determined and classified. The origins of air pollution sources of residential premises are adopted as the classifying criterion. The sources of contamination are defined and assessed. Particular attention is paid to the choice of environmentally friendly building materials. The methodology for assessing toxicity of industrial waste used in the production of housing materials is developed to assess the comfort and environmental safety of home. The idea of creating “Residential buldings ID” containing information on the construction materials used is introduced.

  4. SAVANNAH RIVER SITE'S H-CANYON FACILITY: IMPACTS OF FOREIGN OBLIGATIONS ON SPECIAL NUCLEAR MATERIAL DISPOSITION

    Energy Technology Data Exchange (ETDEWEB)

    Magoulas, V.

    2013-06-03

    The US has a non-proliferation policy to receive foreign and domestic research reactor returns of spent fuel materials of US origin. These spent fuel materials are returned to the Department of Energy (DOE) and placed in storage in the L-area spent fuel basin at the Savannah River Site (SRS). The foreign research reactor returns fall subject to the 123 agreements for peaceful cooperation. These “123 agreements” are named after section 123 of the Atomic Energy Act of 1954 and govern the conditions of nuclear cooperation with foreign partners. The SRS management of these foreign obligations while planning material disposition paths can be a challenge.

  5. Maternal Multiple Micronutrient Supplementation Has Limited Impact on Micronutrient Status of Bangladeshi Infants Compared with Standard Iron Folic Acid Supplementation

    Science.gov (United States)

    We examined the impact of type of maternal micronutrient supplement, time of introduction of a prenatal food supplement and the two interventions combined on micronutrient status of infants in rural Bangladesh. In a community trial, 4436 pregnant women were randomized to Early or Usual start of food...

  6. The impact of a false-positive MRI on the choice for mastectomy in BRCA mutation carriers is limited.

    NARCIS (Netherlands)

    Hoogerbrugge-van der Linden, N.; Kamm, Y.J.; Bult, P.; Landsbergen, K.M.; Bongers, E.M.; Brunner, H.G.; Bonenkamp, H.J.; Hullu, JA de; Ligtenberg, M.J.; Boetes, C.

    2008-01-01

    PURPOSE: To assess the false-positive rate of breast cancer surveillance by magnetic resonance imaging (MRI) in BRCA mutation carriers and the impact of an abnormal mammography or breast MRI on the patients' decision for prophylactic mastectomy. PATIENTS AND METHODS: A total of 196 BRCA mutation

  7. Economic and Environmental Impacts of Improving Growth Rate and Feed Efficiency in Fish Farming Depend on Nitrogen and Density Limitation

    NARCIS (Netherlands)

    Besson, M.; Komen, H.; Vandeputte, M.; Aubin, J.; Boer, de I.J.M.; Arendonk, van J.A.M.

    2014-01-01

    The aim of fish breeding is to increase profit by producing faster growing fish with lower feed intake. However, little is known about the economic and environmental impacts of selective breeding programs for fish. We modelled a fish farm producing African catfish in a Recirculating Aquaculture

  8. The potential impact of an HIV vaccine with limited protection on HIV incidence in Thailand: a modeling study.

    NARCIS (Netherlands)

    Nagelkerke, N.J.; Hontelez, J.A.; Vlas, S.J. de

    2011-01-01

    BACKGROUND: The RV144 trial on the ALVAC/AIDSVAX candidate HIV vaccine, carried out in Thailand, showed short-lived protection against infection. METHODS: Using a deterministic compartmental model we explored the potential impact of this vaccine on heterosexual HIV transmission in Thailand. Both

  9. Ballistic Limit of High-Strength Steel and Al7075-T6 Multi-Layered Plates Under 7.62-mm Armour Piercing Projectile Impact

    OpenAIRE

    Rahman, N.A.; S. Abdullah; Zamri,W. F. H.; M. F. Abdullah; M. Z. Omar; Sajuri, Z.

    2016-01-01

    Abstract This paper presents the computational-based ballistic limit of laminated metal panels comprised of high strength steel and aluminium alloy Al7075-T6 plate at different thickness combinations to necessitate the weight reduction of existing armour steel plate. The numerical models of monolithic configuration, double-layered configuration and triple-layered configuration were developed using a commercial explicit finite element code and were impacted by 7.62 mm armour piercing projectil...

  10. Experimental study on the material dynamic fracture properties by Instrumented Charpy Impact test with single specimen method

    Science.gov (United States)

    Jian, F.; Fulian, D.; Chengzhong, W.

    2003-09-01

    With the determination of load-time curve recorded by Amsler/Roell RKP 450 Instrumented Charpy Impact test and based on the Newton's Second Law, Impact character of a single standard V-notch specimen of X70 pipeline steel under the low temperature -70 ^{circ}C was investigated by studying the impact energy distribution. It was revealed that maximum load point (Fm point) was not exact the dynamic crack initiation, which was detected somewhere prior and very close to Fm point by using Compliance Changing Rate method. This fact was also confirmed by Dynamic CTOD method. That is to say, Impact energy related to the Fm point (i.e. Em) consists not only the crack initiation energy Ei, but a small part of crack extension energy as well. Ratio of Ei/Em was found to be 0.90 just applicable to the material used here. Dynamic fracture toughness JJd was then estimated by modified Rice equation. Crack extension behavior and dynamic crack growth resistance curve (J-Δa) during stable crack propagation period was carefully analyzed by Key Curve method. Finally, methods for evaluating tearing module Tmat, and CTOD curve under the impact test were also briefly introduced in the paper.

  11. Regulation of the transfer market in professional Russian football: impact of the limit for legionaries in 2005–2016

    Directory of Open Access Journals (Sweden)

    Kseniya A. Andreeva

    2017-06-01

    Full Text Available Objective to estimate the efficiency of limit for legionaries as a tool for regulating the Russian transfer market. Methods formal methods of the labor market supply and demand model combinatory analysis statistical methods. Results the article views the order of regulation of the labor relations with foreign legionaries in sports. It is defined that in most countries regulation implies limitation of the number of legionaries who can be claimed for the season or be on the field. The article analyzes the approaches to the transfer market regulation methods as well as the arguments for and against limiting the number of legionaries. Basing on the analysis of literature the author estimates the efficiency of transfer market regulating from the economics viewpoint as well as the results of sports events. The author checks the hypothesis about the inefficiency of the limit as a tool for increasing the quality of the Russian playersrsquo performance based on a number of indicators such as the inefficiency of the national teamrsquos performance number of legionaries their performance etc. The estimation was carried out on the basis of a number of theoretical models 1 model of increasing the footballersrsquo salaries 2 model of free selection of players by the coach and 3 model of quality playersrsquo selection. Basing on these models the hypothesis was disproved of the rapid ldquovictory effectrdquo from the limit ndash the first significant results of the regulation appeared in Russia not earlier than after 10 years. It is supposed that the limit can be explained by G. Akerlofrsquos model by controlling the number of legionaries it is possible to attract more qualified foreign players into the national league. Analysis of the Russian teamsrsquo experience showed that the limit has not resulted in 1 the increase of the legionariesrsquo quality of performance 2 the increase of the playing time of the Russian players on the field in the national

  12. The Cryogenic Impact Resistant Evaluation of Filament Wound Materials for Use in Composite Pressure Vessels Project

    Data.gov (United States)

    National Aeronautics and Space Administration — HyPerComp Engineering Inc. (HEI) and Utah State University (USU) propose to develop technology for lightweight composite materials for use in composite structures...

  13. Correct Implementation of Polarization Constants in Wurtzite Materials and Impact on III-Nitrides

    Science.gov (United States)

    Dreyer, Cyrus E.; Janotti, Anderson; Van de Walle, Chris G.; Vanderbilt, David

    2016-04-01

    Accurate values for polarization discontinuities between pyroelectric materials are critical for understanding and designing the electronic properties of heterostructures. For wurtzite materials, the zincblende structure has been used in the literature as a reference to determine the effective spontaneous polarization constants. We show that, because the zincblende structure has a nonzero formal polarization, this method results in a spurious contribution to the spontaneous polarization differences between materials. In addition, we address the correct choice of "improper" versus "proper" piezoelectric constants. For the technologically important III-nitride materials GaN, AlN, and InN, we determine polarization discontinuities using a consistent reference based on the layered hexagonal structure and the correct choice of piezoelectric constants, and discuss the results in light of available experimental data.

  14. Data collection handbook to support modeling the impacts of radioactive material in soil

    Energy Technology Data Exchange (ETDEWEB)

    Yu, C.; Cheng, J.J.; Jones, L.G.; Wang, Y.Y.; Faillace, E. [Argonne National Lab., IL (United States). Environmental Assessment and Information Sciences Div.; Loureiro, C. [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Escola de Engenharia; Chia, Y.P. [National Taiwan Univ., Taipei (Taiwan, Province of China). Dept. of Geology

    1993-04-01

    A pathway analysis computer code called RESRAD has been developed for implementing US Department of Energy Residual Radioactive Material Guidelines. Hydrogeological, meteorological, geochemical, geometrical (size, area, depth), and material-related (soil, concrete) parameters are used in the RESRAD code. This handbook discusses parameter definitions, typical ranges, variations, measurement methodologies, and input screen locations. Although this handbook was developed primarily to support the application of RESRAD, the discussions and values are valid for other model applications.

  15. The impact of speech material on speech judgement in children with and without cleft palate.

    Science.gov (United States)

    Klintö, Kristina; Salameh, Eva-Kristina; Svensson, Henry; Lohmander, Anette

    2011-01-01

    The chosen method of speech assessment, including type of speech material, may affect speech judgement in children with cleft palate. To assess the effect of different speech materials on speech judgement in 5-year-old children born with or without cleft palate, as well as the reliability of materials by means of intra- and inter-transcriber agreement of consonant transcriptions. Altogether 40 children were studied, 20 born with cleft palate, 20 without. The children were audio recorded at 5 years of age. Speech materials used were: single-word naming, sentence repetition (both developed for cleft palate speech assessment), retelling of a narrative and conversational speech. The samples were phonetically transcribed and inter- and intra-transcriber agreement was calculated. Percentage correct consonants (PCC), percentage correct places (PCP), percentage correct manners (PCM), and percentage active cleft speech characteristics (CSC) were assessed. In addition, an analysis of phonological simplification processes (PSP) was performed. The PCC and CSC results were significantly more accurate in word naming than in all other speech materials in the children with cleft palate, who also achieved more accurate PCP results in word naming than in sentence repetition and conversational speech. Regarding PCM and PSP, performance was significantly more accurate in word naming than in conversational speech. Children without cleft palate did better, irrespective of the speech material. The medians of intra- and inter-transcriber agreement were good in both groups and all speech materials. The closest agreement in the cleft palate group was seen in word naming and the weakest in the retelling task. The results indicate that word naming is the most reliable speech material when the purpose is to assess the best speech performance of a child with cleft palate. If the purpose is to assess connected speech, sentence repetition is a reliable and also valid speech material, with good

  16. Determination of partition and diffusion coefficients of formaldehyde in selected building materials and impact of relative humidity.

    Science.gov (United States)

    Xu, Jing; Zhang, Jianshun S; Liu, Xiaoyu; Gao, Zhi

    2012-06-01

    The partition and effective diffusion coefficients of formaldehyde were measured for three materials (conventional gypsum wallboard, "green" gypsum wallboard, and "green" carpet) under three relative humidity (RH) conditions (20%, 50%, and 70% RH). The "green" materials contained recycled materials and were friendly to environment. A dynamic dual-chamber test method was used. Results showed that a higher relative humidity led to a larger effective diffusion coefficient for two kinds of wallboards and carpet. The carpet was also found to be very permeable resulting in an effective diffusion coefficient at the same order of magnitude with the formaldehyde diffusion coefficient in air. The partition coefficient (K(ma)) of formaldehyde in conventional wallboard was 1.52 times larger at 50% RH than at 20% RH, whereas it decreased slightly from 50% to 70% RH, presumably due to the combined effects of water solubility of formaldehyde and micro-pore blocking by condensed moisture at the high RH level. The partition coefficient of formaldehyde increased slightly with the increase of relative humidity in "green" wallboard and "green" carpet. At the same relative humidity level, the "green" wallboard had larger partition coefficient and effective diffusion coefficient than the conventional wallboard, presumably due to the micro-pore structure differences between the two materials. The data generated could be used to assess the sorption effects of formaldehyde on building materials and to evaluate its impact on the formaldehyde concentration in buildings.

  17. Limited impact on self-concept in individuals with Lynch syndrome; results from a national cohort study

    DEFF Research Database (Denmark)

    Petersen, Helle Vendel; Esplen, Mary Jane; Ladelund, Steen;

    2011-01-01

    An increasing number of individuals seek genetic counseling and hereby learn about hereditary cancer in the family. Lynch syndrome is associated with an inherited high risk for colorectal and gynecological cancer, but knowledge about how family members at risk perceive their situation is limited...

  18. Impact of Bilingual Education Programs on Limited English Proficient Students and Their Peers : Regression Discontinuity Evidence from Texas

    NARCIS (Netherlands)

    Chin, A.; Meltem Daysal, N.; Imberman, S.A.

    2012-01-01

    Abstract: Texas requires a school district to offer bilingual education when its enrollment of limited English proficient (LEP) students in a particular elementary grade and language is twenty or higher. Using school panel data, we find a significant increase in the probability that a district offer

  19. Meaning and impact of the notion of social contract in Rousseau and Kant. Scope and limitations in the democratic theory

    Directory of Open Access Journals (Sweden)

    Jefferson Jaramillo Marín

    2012-12-01

    Full Text Available This article reviews some of the similarities and differences about the political and legal foundation given to the notion of social contract by two modern thinkers: Jean Jacques Rousseau and Immanuel Kant. In the text, it is pointed the revolutionary part of the notion, from showing its principal meanings and impacts. Also, reflection is made on the scope and difficulties of the contractual proposal on the contemporary democratic theory.

  20. Limitation of the spread and impact of infectious coryza through the use of a continuous disinfection programme

    OpenAIRE

    R.R. Bragg

    2004-01-01

    The effect of a continuous disinfection programme, using the non-toxic disinfectant Virukill, in layers, on the spread and impact of infectious coryza, caused by Haemophilus paragallinarum was evaluated. In this experiment, both unvaccinated layers and layers vaccinated against infectious coryza were used. Duplicate smaller groups of vaccinated and unvaccinated chickens were challenged with different serovars of both NAD-dependent as well as NAD-independent isolates of Haemophilus para...