WorldWideScience

Sample records for dynamic e-cell materials

  1. Dynamic fracture characterization of material

    International Nuclear Information System (INIS)

    Kobayashi, A.S.; Emery, A.F.; Liaw, B.M.

    1981-01-01

    The influences of a wide range of material properties, i.e. of A533B steel, a silicon nitride ceramic and a Homalite-100 photoelastic polymer, as well as the influences of the specimen sizes on the dynamic fracture response of fracture specimens are presented in this paper. The results of a numerical study show that the dynamic fracture responses of these fracture specimens of proportional dimensions were indistinguishable provided the normalized dynamic fracture toughness versus normalized crack velocity relations of the three materials coincide. The limited results suggest that should the normalized dynamic fracture toughness versus normalized crack velocity relations between prototype and model materials coincide, then dynamic fracture experiments on scaled models can be used to infer the dynamic fracture response of the prototype. (orig./HP)

  2. Behavior of Brittle Materials Under Dynamic Loading

    National Research Council Canada - National Science Library

    Kanel, G

    2000-01-01

    Dynamic loading of brittle materials is related to many applications, including explosive excavation of rocks, design of ceramic armor, meteor impact on spacecraft windows, particle damage to turbine blades, etc...

  3. Dynamic properties of ceramic materials

    International Nuclear Information System (INIS)

    Grady, D.E.

    1995-02-01

    The present study offers new data and analysis on the transient shock strength and equation-of-state properties of ceramics. Various dynamic data on nine high strength ceramics are provided with wave profile measurements, through velocity interferometry techniques, the principal observable. Compressive failure in the shock wave front, with emphasis on brittle versus ductile mechanisms of deformation, is examined in some detail. Extensive spall strength data are provided and related to the theoretical spall strength, and to energy-based theories of the spall process. Failure waves, as a mechanism of deformation in the transient shock process, are examined. Strength and equation-of-state analysis of shock data on silicon carbide, boron carbide, tungsten carbide, silicon dioxide and aluminum nitride is presented with particular emphasis on phase transition properties for the latter two. Wave profile measurements on selected ceramics are investigated for evidence of rate sensitive elastic precursor decay in the shock front failure process

  4. Recent developments in dynamic testing of materials

    Directory of Open Access Journals (Sweden)

    Gilat Amos

    2015-01-01

    Full Text Available New techniques for dynamic characterization of materials that have been developed in the last three years (since the last DYMAT conference in 2012, and results from recent dynamic testing of Inconel 718 are presented. The first development is a dynamic punch test in which three dimensional Digital Image Correlation (DIC is used to measure the deformation of the rear surface of a specimen as it being penetrated. The second experimental technique that is under development is a dynamic tension experiment in which full-field strain measurement with DIC and full-field temperature measurement are done simultaneously during the test.

  5. Lattice dynamics and molecular dynamics simulation of complex materials

    International Nuclear Information System (INIS)

    Chaplot, S.L.

    1997-01-01

    In this article we briefly review the lattice dynamics and molecular dynamics simulation techniques, as used for complex ionic and molecular solids, and demonstrate a number of applications through examples of our work. These computational studies, along with experiments, have provided microscopic insight into the structure and dynamics, phase transitions and thermodynamical properties of a variety of materials including fullerene, high temperature superconducting oxides and geological minerals as a function of pressure and temperature. The computational techniques also allow the study of the structures and dynamics associated with disorder, defects, surfaces, interfaces etc. (author)

  6. Advanced Plasmonic Materials for Dynamic Color Display.

    Science.gov (United States)

    Shao, Lei; Zhuo, Xiaolu; Wang, Jianfang

    2018-04-01

    Plasmonic structures exhibit promising applications in high-resolution and durable color generation. Research on advanced hybrid plasmonic materials that allow dynamically reconfigurable color control has developed rapidly in recent years. Some of these results may give rise to practically applicable reflective displays in living colors with high performance and low power consumption. They will attract broad interest from display markets, compared with static plasmonic color printing, for example, in applications such as digital signage, full-color electronic paper, and electronic device screens. In this progress report, the most promising recent examples of utilizing advanced plasmonic materials for the realization of dynamic color display are highlighted and put into perspective. The performances, advantages, and disadvantages of different technologies are discussed, with emphasis placed on both the potential and possible limitations of various hybrid materials for dynamic plasmonic color display. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Experience with dynamic material control subsystems

    International Nuclear Information System (INIS)

    Severe, W.R.; Hagen, J.; Siebelist, R.; Wagner, R.P.; Olson, W.M.

    1977-01-01

    Operation of a Dynamic Material Control (DYMAC) prototype system has yielded some useful information for installing the final system. We discovered a bias between two methods for measuring filtrates. Evaluation of a unit process dynamic balance brought to light an operating procedure that weakens the accountability goals of the DYMAC system. We were able to correct both situations for the final system and learned that we must regularly monitor the system once it is operational for similar discrepancies

  8. Sandia Dynamic Materials Program Strategic Plan.

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-05-01

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

  9. Dynamic mechanical properties of buffer material

    International Nuclear Information System (INIS)

    Takaji, Kazuhiko; Taniguchi, Wataru

    1999-11-01

    The buffer material is expected to maintain its low water permeability, self-sealing properties, radionuclides adsorption and retardation properties, thermal conductivity, chemical buffering properties, overpack supporting properties, stress buffering properties, etc. over a long period of time. Natural clay is mentioned as a material that can relatively satisfy above. Among the kinds of natural clay, bentonite when compacted is superior because (i) it has exceptionally low water permeability and properties to control the movement of water in buffer, (ii) it fills void spaces in the buffer and fractures in the host rock as it swells upon water uptake, (iii) it has the ability to exchange cations and to adsorb cationic radioelements. In order to confirm these functions for the purpose of safety assessment, it is necessary to evaluate buffer properties through laboratory tests and engineering-scale tests, and to make assessments based on the ranges in the data obtained. This report describes the procedures, test conditions, results and examinations on the buffer material of dynamic triaxial tests, measurement of elastic wave velocity and liquefaction tests that aim at getting hold of dynamic mechanical properties. We can get hold of dependency on the shearing strain of the shearing modulus and hysteresis damping constant, the application for the mechanical model etc. by dynamic triaxial tests, the acceptability of maximum shearing modulus obtained from dynamic triaxial tests etc. by measurement of elastic wave velocity and dynamic strength caused by cyclic stress etc. by liquefaction tests. (author)

  10. Material properties under intensive dynamic loading

    CERN Document Server

    Cherne, Frank J; Zhernokletov, Mikhail V; Glushak, B L; Zocher, Marvin A

    2007-01-01

    Understanding the physical and thermomechanical response of materials subjected to intensive dynamic loading is a challenge of great significance in engineering today. This volume assumes the task of gathering both experimental and diagnostic methods in one place, since not much information has been previously disseminated in the scientific literature.

  11. Dynamic frictional contact for elastic viscoplastic material

    Directory of Open Access Journals (Sweden)

    Kenneth L. Kuttler

    2007-05-01

    Full Text Available Using a general theory for evolution inclusions, existence and uniqueness theorems are obtained for weak solutions to a frictional dynamic contact problem for elastic visco-plastic material. An existence theorem in the case where the friction coefficient is discontinuous is also presented.

  12. High Speed Dynamics in Brittle Materials

    Science.gov (United States)

    Hiermaier, Stefan

    2015-06-01

    Brittle Materials under High Speed and Shock loading provide a continuous challenge in experimental physics, analysis and numerical modelling, and consequently for engineering design. The dependence of damage and fracture processes on material-inherent length and time scales, the influence of defects, rate-dependent material properties and inertia effects on different scales make their understanding a true multi-scale problem. In addition, it is not uncommon that materials show a transition from ductile to brittle behavior when the loading rate is increased. A particular case is spallation, a brittle tensile failure induced by the interaction of stress waves leading to a sudden change from compressive to tensile loading states that can be invoked in various materials. This contribution highlights typical phenomena occurring when brittle materials are exposed to high loading rates in applications such as blast and impact on protective structures, or meteorite impact on geological materials. A short review on experimental methods that are used for dynamic characterization of brittle materials will be given. A close interaction of experimental analysis and numerical simulation has turned out to be very helpful in analyzing experimental results. For this purpose, adequate numerical methods are required. Cohesive zone models are one possible method for the analysis of brittle failure as long as some degree of tension is present. Their recent successful application for meso-mechanical simulations of concrete in Hopkinson-type spallation tests provides new insight into the dynamic failure process. Failure under compressive loading is a particular challenge for numerical simulations as it involves crushing of material which in turn influences stress states in other parts of a structure. On a continuum scale, it can be modeled using more or less complex plasticity models combined with failure surfaces, as will be demonstrated for ceramics. Models which take microstructural

  13. Optical dynamic deformation measurements at translucent materials.

    Science.gov (United States)

    Philipp, Katrin; Koukourakis, Nektarios; Kuschmierz, Robert; Leithold, Christoph; Fischer, Andreas; Czarske, Jürgen

    2015-02-15

    Due to their high stiffness-to-weight ratio, glass fiber-reinforced polymers are an attractive material for rotors, e.g., in the aerospace industry. A fundamental understanding of the material behavior requires non-contact, in-situ dynamic deformation measurements. The high surface speeds and particularly the translucence of the material limit the usability of conventional optical measurement techniques. We demonstrate that the laser Doppler distance sensor provides a powerful and reliable tool for monitoring radial expansion at fast rotating translucent materials. We find that backscattering in material volume does not lead to secondary signals as surface scattering results in degradation of the measurement volume inside the translucent medium. This ensures that the acquired signal contains information of the rotor surface only, as long as the sample surface is rough enough. Dynamic deformation measurements of fast-rotating fiber-reinforced polymer composite rotors with surface speeds of more than 300 m/s underline the potential of the laser Doppler sensor.

  14. Dynamic nonlinear elasticity in geo materials

    International Nuclear Information System (INIS)

    Ostrovsky, L.A.; Johnson, P.A.

    2001-01-01

    The nonlinear elastic behaviour of earth materials is an extremely rich topic, one that has broad implications to earth and materials sciences, including strong ground motion, rock physics, nondestructive evaluation and materials science. The mechanical properties of rock appear to place it in a broader class of materials, it can be named the Structural nonlinear elasticity class (also Mesoscopic/nano scale elasticity, or MS/NSE class). These terms are in contrast to materials that display classical, Atomic Elasticity, such as most fluids and monocrystalline solids. The difference between these two categories of materials is both in intensity and origin of their nonlinear response. The nonlinearity of atomic elastic materials is due to the atomic/molecular lattice anharmonicity. The latter is relatively small because the intermolecular forces are extremely strong. In contrast, the materials considered below contain small soft features that it is called the bond system (cracks, grain contacts, dislocations, etc.) within a hard matrix and relaxation (slow dynamical effects) are characteristic, non of which appear in atomic elastic materials. The research begins with a brief historical background from nonlinear acoustics to the recent developments in rock nonlinearity. This is followed by an overview of some representative laboratory measurements which serve as primary indicators of nonlinear behaviour, followed by theoretical development, and finally, mention a variety of observations of nonlinearity under field conditions and applications to nondestructive testing of materials. The goal is not to survey all papers published in the are but to demonstrate some experimental and theoretical results and ideas that will the reader to become oriented in this broad and rapidly growing area bridging macro-, meso- and microscale (nano scale) phenomena in physics, materials science, and geophysics

  15. Dynamics of Liquids Confined in Porous Materials

    DEFF Research Database (Denmark)

    Berg, Marcella Cabrera

    mobility of the hydrogen atoms, mostly from water, present in conventional GIC. Water plays a big part in the setting process in GIC. It is the reaction medium in which the cations leach to crosslink. Furthermore, water also hydrates the siliceous hydrogel and the metal polyacrylate salts. In matured GIC...... dynamics in such complex hierarchical structure, where different motions occur in a broad range of time scales and simultaneously, can be difficult. So in this Ph.D. thesis, the experimental data was combined with preliminary classical molecular dynamics simulations (MD), aiming to investigate...... the different nanoscale water dynamics in the GIC. This unique approach opens new possibilities to better explore all the information contained in the neutron spectroscopy data. Selected materials were investigated by first understanding the molecular motions of the different aqueous polyacrylic acid solutions...

  16. Dynamic nuclear polarization of irradiated target materials

    International Nuclear Information System (INIS)

    Seely, M.L.

    1982-01-01

    Polarized nucleon targets used in high energy physics experiments usually employ the method of dynamic nuclear polarization (DNP) to polarize the protons or deuterons in an alcohol. DNP requires the presence of paramagnetic centers, which are customarily provided by a chemical dopant. These chemically doped targets have a relatively low polarizable nucleon content and suffer from loss of polarization when subjected to high doses of ionizing radiation. If the paramagnetic centers formed when the target is irradiated can be used in the DNP process, it becomes possible to produce targets using materials which have a relatively high polarizable nucleon content, but which are not easily doped by chemical means. Furthermore, the polarization of such targets may be much more radiation resistant. Dynamic nuclear polarization in ammonia, deuterated ammonia, ammonium hydroxide, methylamine, borane ammonia, butonal, ethane and lithium borohydride has been studied. These studies were conducted at the Stanford Linear Accelerator Center using the Yale-SLAC polarized target system. Results indicate that the use of ammonia and deuterated ammonia as polarized target materials would make significant increases in polarized target performance possible

  17. Deformed Materials: Towards a Theory of Materials Morphology Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Sethna, James P [Laboratory of Atomic and Solid State Physics, Cornell University

    2017-06-28

    This grant supported work on the response of crystals to external stress. Our primary work described how disordered structural materials break in two (statistical models of fracture in disordered materials), studied models of deformation bursts (avalanches) that mediate deformation on the microscale, and developed continuum dislocation dynamics models for plastic deformation (as when scooping ice cream bends a spoon, Fig. 9). Glass is brittle -- it breaks with almost atomically smooth fracture surfaces. Many metals are ductile -- when they break, the fracture surface is locally sheared and stretched, and it is this damage that makes them hard to break. Bone and seashells are made of brittle material, but they are strong because they are disordered -- lots of little cracks form as they are sheared and near the fracture surface, diluting the external force. We have studied materials like bone and seashells using simulations, mathematical tools, and statistical mechanics models from physics. In particular, we studied the extreme values of fracture strengths (how likely will a beam in a bridge break far below its design strength), and found that the traditional engineering tools could be improved greatly. We also studied fascinating crackling-noise precursors -- systems which formed microcracks of a broad range of sizes before they broke. Ductile metals under stress undergo irreversible plastic deformation -- the planes of atoms must slide across one another (through the motion of dislocations) to change the overall shape in response to the external force. Microscopically, the dislocations in crystals move in bursts of a broad range of sizes (termed 'avalanches' in the statistical mechanics community, whose motion is deemed 'crackling noise'). In this grant period, we resolved a longstanding mystery about the average shape of avalanches of fixed duration (using tools related to an emergent scale invariance), we developed the fundamental theory

  18. Canopy Dynamics in Nanoscale Ionic Materials

    KAUST Repository

    Jespersen, Michael L.

    2010-07-27

    Nanoscale ionic materials (NIMS) are organic - inorganic hybrids in which a core nanostructure is functionalized with a covalently attached corona and an ionically tethered organic canopy. NIMS are engineered to be liquids under ambient conditions in the absence of solvent and are of interest for a variety of applications. We have used nuclear magnetic resonance (NMR) relaxation and pulse-field gradient (PFG) diffusion experiments to measure the canopy dynamics of NIMS prepared from 18-nm silica cores modified by an alkylsilane monolayer possessing terminal sulfonic acid functionality, paired with an amine-terminated ethylene oxide/propylene oxide block copolymer canopy. Carbon NMR studies show that the block copolymer canopy is mobile both in the bulk and in the NIMS and that the fast (ns) dynamics are insensitive to the presence of the silica nanoparticles. Canopy diffusion in the NIMS is slowed relative to the neat canopy, but not to the degree predicted from the diffusion of hard-sphere particles. Canopy diffusion is not restricted to the surface of the nanoparticles and shows unexpected behavior upon addition of excess canopy. Taken together, these data indicate that the liquid-like behavior in NIMS is due to rapid exchange of the block copolymer canopy between the ionically modified nanoparticles. © 2010 American Chemical Society.

  19. Canopy Dynamics in Nanoscale Ionic Materials

    KAUST Repository

    Jespersen, Michael L.; Mirau, Peter A.; Meerwall, Ernst von; Vaia, Richard A.; Rodriguez, Robert; Giannelis, Emmanuel P.

    2010-01-01

    Nanoscale ionic materials (NIMS) are organic - inorganic hybrids in which a core nanostructure is functionalized with a covalently attached corona and an ionically tethered organic canopy. NIMS are engineered to be liquids under ambient conditions in the absence of solvent and are of interest for a variety of applications. We have used nuclear magnetic resonance (NMR) relaxation and pulse-field gradient (PFG) diffusion experiments to measure the canopy dynamics of NIMS prepared from 18-nm silica cores modified by an alkylsilane monolayer possessing terminal sulfonic acid functionality, paired with an amine-terminated ethylene oxide/propylene oxide block copolymer canopy. Carbon NMR studies show that the block copolymer canopy is mobile both in the bulk and in the NIMS and that the fast (ns) dynamics are insensitive to the presence of the silica nanoparticles. Canopy diffusion in the NIMS is slowed relative to the neat canopy, but not to the degree predicted from the diffusion of hard-sphere particles. Canopy diffusion is not restricted to the surface of the nanoparticles and shows unexpected behavior upon addition of excess canopy. Taken together, these data indicate that the liquid-like behavior in NIMS is due to rapid exchange of the block copolymer canopy between the ionically modified nanoparticles. © 2010 American Chemical Society.

  20. An introduction to the mathematical theory of dynamic materials

    CERN Document Server

    Lurie, Konstantin A

    2017-01-01

    Mathematical treatment to properties of dynamic materials, material substances whose properties are variable in space and time are examined in this book. This new edition emphasizes the differences between material optimization techniques in statics and dynamics. Systems with one spatial coordinate and time are used to illustrate essentials of temporal property change in this setting and prompt forthcoming extensions and technical improvements. Since the release of the first edition, a number of new results have created a more complete picture of unusual effects hidden in spatio-temporal material geometry. This renewed look has revealed a conceptually new mechanism of relaxation of material optimization problems in dynamics, which has led to additional resources for optimization previously concealed in the property layouts. Dynamic materials are studied in this book from the following perspectives: ability to appear in dissimilar implementations, universality as formations that are thermodynamically open, and...

  1. Charge carrier dynamics in photovoltaic materials

    NARCIS (Netherlands)

    Jensen, S.A.

    2014-01-01

    We employ the experimental technique THz Time Domain spectroscopy (THz-TDS) to study the optoelectronic properties of potential photovoltaic materials. This all-optical method is useful for probing photoconductivities in a range of materials on ultrafast timescales without the application of

  2. Ultrafast dynamic ellipsometry and spectroscopies of laser shocked materials

    Energy Technology Data Exchange (ETDEWEB)

    Mcgrane, Shawn David [Los Alamos National Laboratory; Bolme, Cindy B [Los Alamos National Laboratory; Whitley, Von H [Los Alamos National Laboratory; Moore, David S [Los Alamos National Laboratory

    2010-01-01

    Ultrafast ellipsometry and transient absorption spectroscopies are used to measure material dynamics under extreme conditions of temperature, pressure, and volumetric compression induced by shock wave loading with a chirped, spectrally clipped shock drive pulse.

  3. Dynamic Initiation and Propagation of Multiple Cracks in Brittle Materials

    Directory of Open Access Journals (Sweden)

    Xiaodan Ren

    2013-07-01

    Full Text Available Brittle materials such as rock and ceramic usually exhibit apparent increases of strength and toughness when subjected to dynamic loading. The reasons for this phenomenon are not yet well understood, although a number of hypotheses have been proposed. Based on dynamic fracture mechanics, the present work offers an alternate insight into the dynamic behaviors of brittle materials. Firstly, a single crack subjected to stress wave excitations is investigated to obtain the dynamic crack-tip stress field and the dynamic stress intensity factor. Second, based on the analysis of dynamic stress intensity factor, the fracture initiation sizes and crack size distribution under different loading rates are obtained, and the power law with the exponent of −2/3 is derived to describe the fracture initiation size. Third, with the help of the energy balance concept, the dynamic increase of material strength is directly derived based on the proposed multiple crack evolving criterion. Finally, the model prediction is compared with the dynamic impact experiments, and the model results agree well with the experimentally measured dynamic increasing factor (DIF.

  4. Compaction dynamics of crunchy granular material

    Directory of Open Access Journals (Sweden)

    Guillard François

    2017-01-01

    Full Text Available Compaction of brittle porous material leads to a wide variety of densification patterns. Static compaction bands occurs naturally in rocks or bones, and have important consequences in industry for the manufacturing of powder tablets or metallic foams for example. Recently, oscillatory compaction bands have been observed in brittle porous media like snow or cereals. We will discuss the great variety of densification patterns arising during the compaction of puffed rice, including erratic compaction at low velocity, one or several travelling compaction bands at medium velocity and homogeneous compaction at larger velocity. The conditions of existence of each pattern are studied thanks to a numerical spring lattice model undergoing breakage and is mapped to the phase diagram of the patterns based on dimensionless characteristic quantities. This also allows to rationalise the evolution of the compaction behaviour during a single test. Finally, the localisation of compaction bands is linked to the strain rate sensitivity of the material.

  5. Compaction dynamics of crunchy granular material

    Science.gov (United States)

    Guillard, François; Golshan, Pouya; Shen, Luming; Valdès, Julio R.; Einav, Itai

    2017-06-01

    Compaction of brittle porous material leads to a wide variety of densification patterns. Static compaction bands occurs naturally in rocks or bones, and have important consequences in industry for the manufacturing of powder tablets or metallic foams for example. Recently, oscillatory compaction bands have been observed in brittle porous media like snow or cereals. We will discuss the great variety of densification patterns arising during the compaction of puffed rice, including erratic compaction at low velocity, one or several travelling compaction bands at medium velocity and homogeneous compaction at larger velocity. The conditions of existence of each pattern are studied thanks to a numerical spring lattice model undergoing breakage and is mapped to the phase diagram of the patterns based on dimensionless characteristic quantities. This also allows to rationalise the evolution of the compaction behaviour during a single test. Finally, the localisation of compaction bands is linked to the strain rate sensitivity of the material.

  6. Calculation of the dynamic air flow resistivity of fibre materials

    DEFF Research Database (Denmark)

    Tarnow, Viggo

    1997-01-01

    The acoustic attenuation of acoustic fiber materials is mainly determined by the dynamic resistivity to an oscillating air flow. The dynamic resistance is calculated for a model with geometry close to the geometry of real fibre material. The model constists of parallel cylinders placed randomly.......The second procedure is an extension to oscillating air flow of the Brinkman self-consistent procedure for dc flow. The procedures are valid for volume concentrations of cylinders less than 0.1. The calculations show that for the density of fibers of interest for acoustic fibre materials the simple self...

  7. Magnetic flux dynamics in superconducting materials

    International Nuclear Information System (INIS)

    Hernandez Nieves, Alexander

    2004-01-01

    The magnetization curves, the Bean-Livingston barrier in type I and type II superconductors, the ac magnetic response, the effects of thermal fluctuations on the magnetic behavior and the different dissipation mechanism at microwave frequencies are investigated in mesoscopic superconductors.For small mesoscopic samples we study the peaks and discontinuous jumps found in the magnetization as a function of magnetic field.To interpret these jumps we consider that vortices located inside the sample induce a reinforcement of the Bean- Livingston surface barrier at fields greater than the first penetration field Hp1.This leads to multiple penetration fields Hpi Hp1;Hp2;Hp3;... for vortex entrance in mesoscopic samples.For low-T c mesoscopic superconductors we found that the meta-stable states due to the surface barrier have a large half-life time, which leads to the hysteresis in the magnetization curves as observed experimentally.A very different behavior appears for high-T c mesoscopic superconductors where thermally activated vortex entrance/exit through surface barriers is frequent.This leads to a reduction of the magnetization and a non-integer average number of flux quanta penetrating the superconductor.At microwave frequencies we found that each vortex penetration event produces a significant suppression of the ac losses since the imaginary part of the ac susceptibility X ( H d c) as a function of the magnetic field (Hdc) increases before the penetration of vortices and then it decreases abruptly after vortices have entered into the sample.We show that nascent vortices (vortices that are partly inside the sample and nucleated at the surface) play an important role in the dynamic behavior of mesoscopic samples. In type I macroscopic superconductors with first-principles simulations of the TDGL equations we have been able to reproduce several features of the intermediate state observed in experiments.Particularly, droplet and striped patterns are obtained depending

  8. Dynamic Materials do the Trick in Participatory Business Modeling

    DEFF Research Database (Denmark)

    Caglio, Agnese; Buur, Jacob

    In this position paper we suggest that design material with dynamic behaviour is particularly suited to scaffold groups of diverse participants in discussing the ‘if – then’ causalities of business models. Based on video data from a number of innovation project workshops we present a comparison...... matrix of five different material types for participatory business modeling. The comparison matrix highlights patterns in the use of materials, and how they allow people to participate, negotiate and make meaning....

  9. The potential value of dynamic materials control in international safeguards

    International Nuclear Information System (INIS)

    Keepin, G.R.; Lovett, J.E.

    1979-01-01

    The difficulties inherent in conventional materials accountancy based on semi-annual or annual shutdown cleanout physical inventories have been recognized for many years. The increasing importance of international nuclear materials safeguards, coupled with the availability of advanced non-destructive measurement technology which could be installed on or near process lines, has led to the development of the concept of advanced or dynamic materials control. The potential benefits of dynamic materials control in terms of significantly improved detection capabilities (ranging from a few kilograms of plutonium down to perhaps a few hundred grams, even for large-scale bulk processing facilities), and even more dramatically improved detection timeliness (typically a few days, and potentially only a few hours, in advanced facilities), are reviewed. At least twelve major dynamic material control systems already in existence or in the process of being installed are noted, and some of the essential characteristics are discussed. Some currently unresolved questions are explored, and future prospects for the concept of dynamic material control in international safeguards are reviewed. (author)

  10. Design of advanced materials for linear and nonlinear dynamics

    DEFF Research Database (Denmark)

    Frandsen, Niels Morten Marslev

    to reveal the fundamental dynamic characteristics and thus the relevant design parameters.The thesis is built around the characterization of two one-dimensional, periodic material systems. The first is a nonlinear mass-spring chain with periodically varying material properties, representing a simple......The primary catalyst of this PhD project has been an ambition to design advanced materials and structural systems including, and possibly even exploiting, nonlinear phenomena such as nonlinear modal interaction leading to energy conversion between modes. An important prerequisite for efficient...... but general model of inhomogeneous structural materials with nonlinear material characteristics. The second material system is an “engineered” material in the sense that a classical structural element, a linear elastic and homogeneous rod, is “enhanced” by applying a mechanism on its surface, amplifying...

  11. A comprehensive dynamic modeling approach for giant magnetostrictive material actuators

    International Nuclear Information System (INIS)

    Gu, Guo-Ying; Zhu, Li-Min; Li, Zhi; Su, Chun-Yi

    2013-01-01

    In this paper, a comprehensive modeling approach for a giant magnetostrictive material actuator (GMMA) is proposed based on the description of nonlinear electromagnetic behavior, the magnetostrictive effect and frequency response of the mechanical dynamics. It maps the relationships between current and magnetic flux at the electromagnetic part to force and displacement at the mechanical part in a lumped parameter form. Towards this modeling approach, the nonlinear hysteresis effect of the GMMA appearing only in the electrical part is separated from the linear dynamic plant in the mechanical part. Thus, a two-module dynamic model is developed to completely characterize the hysteresis nonlinearity and the dynamic behaviors of the GMMA. The first module is a static hysteresis model to describe the hysteresis nonlinearity, and the cascaded second module is a linear dynamic plant to represent the dynamic behavior. To validate the proposed dynamic model, an experimental platform is established. Then, the linear dynamic part and the nonlinear hysteresis part of the proposed model are identified in sequence. For the linear part, an approach based on axiomatic design theory is adopted. For the nonlinear part, a Prandtl–Ishlinskii model is introduced to describe the hysteresis nonlinearity and a constrained quadratic optimization method is utilized to identify its coefficients. Finally, experimental tests are conducted to demonstrate the effectiveness of the proposed dynamic model and the corresponding identification method. (paper)

  12. AC Calorimetric Design for Dynamic of Biological Materials

    OpenAIRE

    Shigeo Imaizumi

    2006-01-01

    We developed a new AC calorimeter for the measurement of dynamic specific heat capacity in liquids, including aqueous suspensions of biological materials. This method has several advantages. The first is that a high-resolution measurement of heat capacity, inmillidegrees, can be performed as a function of temperature, even with a very small sample. Therefore, AC calorimeter is a powerful tool to study critical behavior a tphase transition in biological materials. The second advantage is that ...

  13. Studies of the dynamic properties of materials using neutron scattering

    International Nuclear Information System (INIS)

    Lovesey, S.W.; Windsor, C.G.

    1985-09-01

    The dynamic properties of materials using the neutron scattering technique is reviewed. The basic properties of both nuclear scattering and magnetic scattering are summarized. The experimental methods used in neutron scattering are described, along with access to neutron sources, and neutron inelastic instruments. Applied materials science using inelastic neutron scattering; rotational tunnelling of a methyl group; molecular diffusion from quasi-elastic scattering; and the diffusion of colloidal particles and poly-nuclear complexes; are also briefly discussed. (U.K.)

  14. Development and demonstration program for dynamic nuclear materials control

    International Nuclear Information System (INIS)

    Augustson, R.H.; Baron, N.; Ford, R.F.; Ford, W.; Hagen, J.; Li, T.K.; Marshall, R.S.; Reams, V.S.; Severe, W.R.; Shirk, D.G.

    1978-01-01

    A significant portion of the Los Alamos Scientific Laboratory Safeguards Program is directed toward the development and demonstration of dynamic nuclear materials control. The building chosen for the demonstration system is the new Plutonium Processing Facility in Los Alamos, which houses such operations as metal-to-oxide conversion, fuel pellet fabrication, and scrap recovery. A DYnamic MAterials Control (DYMAC) system is currently being installed in the facility as an integral part of the processing operation. DYMAC is structured around interlocking unit-process accounting areas. It relies heavily on nondestructive assay measurements made in the process line to draw dynamic material balances in near real time. In conjunction with the nondestructive assay instrumentation, process operators use interactive terminals to transmit additional accounting and process information to a dedicated computer. The computer verifies and organizes the incoming data, immediately updates the inventory records, monitors material in transit using elapsed time, and alerts the Nuclear Materials Officer in the event that material balances exceed the predetermined action limits. DYMAC is part of the United States safeguards system under control of the facility operator. Because of its advanced features, the system will present a new set of inspection conditions to the IAEA, whose response is the subject of a study being sponsored by the US-IAEA Technical Assistance Program. The central issue is how the IAEA can use the increased capabilities of such a system and still maintain independent verification

  15. Scoping Future Policy Dynamics in Raw Materials Through Scenarios Testing

    Science.gov (United States)

    Correia, Vitor; Keane, Christopher; Sturm, Flavius; Schimpf, Sven; Bodo, Balazs

    2017-04-01

    The International Raw Materials Observatory (INTRAW) project is working towards a sustainable future for the European Union in access to raw materials, from an availability, economical, and environmental framework. One of the major exercises for the INTRAW project is the evaluation of potential future scenarios for 2050 to frame economic, research, and environmental policy towards a sustainable raw materials supply. The INTRAW consortium developed three possible future scenarios that encompass defined regimes of political, economic, and technological norms. The first scenario, "Unlimited Trade," reflects a world in which free trade continues to dominate the global political and economic environment, with expectations of a growing demand for raw materials from widely distributed global growth. The "National Walls" scenario reflects a world where nationalism and economic protectionism begins to dominate, leading to stagnating economic growth and uneven dynamics in raw materials supply and demand. The final scenario, "Sustainability Alliance," examines the dynamics of a global political and economic climate that is focused on environmental and economic sustainability, leading towards increasingly towards a circular raw materials economy. These scenarios were reviewed, tested, and provided simulations of impacts with members of the Consortium and a panel of global experts on international raw materials issues which led to expected end conditions for 2050. Given the current uncertainty in global politics, these scenarios are informative to identifying likely opportunities and crises. The details of these simulations and expected responses to the research demand, technology investments, and economic components of raw materials system will be discussed.

  16. Dynamic compressive mechanical response of a soft polymer material

    NARCIS (Netherlands)

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

    2015-01-01

    The dynamic mechanical behaviour of a soft polymer material (Clear Flex 75) was studied using a split Hopkinson pressure bar (SHPB) apparatus. Mechanical properties have been determined at moderate to high strain rates. Real time deformation and fracture were recorded using a high-speed camera.

  17. Nonlinear dynamic characterization of two-dimensional materials

    NARCIS (Netherlands)

    Davidovikj, D.; Alijani, F.; Cartamil Bueno, S.J.; van der Zant, H.S.J.; Amabili, M.; Steeneken, P.G.

    2017-01-01

    Owing to their atomic-scale thickness, the resonances of two-dimensional (2D) material membranes show signatures of nonlinearities at forces of only a few picoNewtons. Although the linear dynamics of membranes is well understood, the exact relation between the nonlinear response and the resonator's

  18. Cellular Manufacturing System with Dynamic Lot Size Material Handling

    Science.gov (United States)

    Khannan, M. S. A.; Maruf, A.; Wangsaputra, R.; Sutrisno, S.; Wibawa, T.

    2016-02-01

    Material Handling take as important role in Cellular Manufacturing System (CMS) design. In several study at CMS design material handling was assumed per pieces or with constant lot size. In real industrial practice, lot size may change during rolling period to cope with demand changes. This study develops CMS Model with Dynamic Lot Size Material Handling. Integer Linear Programming is used to solve the problem. Objective function of this model is minimizing total expected cost consisting machinery depreciation cost, operating costs, inter-cell material handling cost, intra-cell material handling cost, machine relocation costs, setup costs, and production planning cost. This model determines optimum cell formation and optimum lot size. Numerical examples are elaborated in the paper to ilustrate the characterictic of the model.

  19. Exploiting the Dynamics of Soft Materials for Machine Learning.

    Science.gov (United States)

    Nakajima, Kohei; Hauser, Helmut; Li, Tao; Pfeifer, Rolf

    2018-06-01

    Soft materials are increasingly utilized for various purposes in many engineering applications. These materials have been shown to perform a number of functions that were previously difficult to implement using rigid materials. Here, we argue that the diverse dynamics generated by actuating soft materials can be effectively used for machine learning purposes. This is demonstrated using a soft silicone arm through a technique of multiplexing, which enables the rich transient dynamics of the soft materials to be fully exploited as a computational resource. The computational performance of the soft silicone arm is examined through two standard benchmark tasks. Results show that the soft arm compares well to or even outperforms conventional machine learning techniques under multiple conditions. We then demonstrate that this system can be used for the sensory time series prediction problem for the soft arm itself, which suggests its immediate applicability to a real-world machine learning problem. Our approach, on the one hand, represents a radical departure from traditional computational methods, whereas on the other hand, it fits nicely into a more general perspective of computation by way of exploiting the properties of physical materials in the real world.

  20. PLASTICITY OF SELECTED METALLIC MATERIALS IN DYNAMIC DEFORMATION CONDITIONS

    Directory of Open Access Journals (Sweden)

    Jacek PAWLICKI

    2014-06-01

    Full Text Available Characteristics of a modernized flywheel machine has been presented in the paper. The laboratory stand enables to perform dynamic tensile tests and impact bending with a linear velocity of the enforcing element in the range of 5÷40 m/s. A new data acquisition system, based on the tensometric sensors, allows for significant qualitative improvement of registered signals. Some preliminary dynamic forming tests were performed for the selected group of metallic materials. Subsequent microstructural examinations and identification of the fracture type enabled to describe a correlation between strain rate, strain and microstructure.

  1. Modeling the dynamic crush of impact mitigating materials

    International Nuclear Information System (INIS)

    Logan, R.W.; McMichael, L.D.

    1995-01-01

    Crushable materials are commonly utilized in the design of structural components to absorb energy and mitigate shock during the dynamic impact of a complex structure, such as an automobile chassis or drum-type shipping container. The development and application of several finite-element material models which have been developed at various times at LLNL for DYNA3D will be discussed. Between the models, they are able to account for several of the predominant mechanisms which typically influence the dynamic mechanical behavior of crushable materials. One issue we addressed was that no single existing model would account for the entire gambit of constitutive features which are important for crushable materials. Thus, we describe the implementation and use of an additional material model which attempts to provide a more comprehensive model of the mechanics of crushable material behavior. This model combines features of the pre-existing DYNA models and incorporates some new features as well in an invariant large-strain formulation. In addition to examining the behavior of a unit cell in uniaxial compression, two cases were chosen to evaluate the capabilities and accuracy of the various material models in DYNA. In the first case, a model for foam filled box beams was developed and compared to test data from a 4-point bend test. The model was subsequently used to study its effectiveness in energy absorption in an aluminum extrusion, spaceframe, vehicle chassis. The second case examined the response of the AT-400A shipping container and the performance of the overpack material during accident environments selected from 10CFR71 and IAEA regulations

  2. Discrete event dynamic system (DES)-based modeling for dynamic material flow in the pyroprocess

    International Nuclear Information System (INIS)

    Lee, Hyo Jik; Kim, Kiho; Kim, Ho Dong; Lee, Han Soo

    2011-01-01

    A modeling and simulation methodology was proposed in order to implement the dynamic material flow of the pyroprocess. Since the static mass balance provides the limited information on the material flow, it is hard to predict dynamic behavior according to event. Therefore, a discrete event system (DES)-based model named, PyroFlow, was developed at the Korea Atomic Energy Research Institute (KAERI). PyroFlow is able to calculate dynamic mass balance and also show various dynamic operational results in real time. By using PyroFlow, it is easy to rapidly predict unforeseeable results, such as throughput in unit process, accumulated product in buffer and operation status. As preliminary simulations, bottleneck analyses in the pyroprocess were carried out and consequently it was presented that operation strategy had influence on the productivity of the pyroprocess.

  3. Canopy Dynamics in Nanoscale Ionic Materials Probed by NMR

    Science.gov (United States)

    Mirau, Peter

    2013-03-01

    Nanoscale ionic materials (NIMs) are hybrids prepared from ionically functionalized nanoparticles (NP) neutralized by oligomeric polymer counter-ions. NIMs are designed to behave as liquids under ambient conditions in the absence of solvent and have no volatile organic content, making them useful for a number of applications. We have used NMR relaxation and pulse-field gradient NMR to probe local and collective canopy dynamics in NIMs based on silica nanoparticles (NP), fullerols and proteins in order to understand the relationship between the core and canopy structure and the bulk properties. The NMR studies show that the canopy dynamics depend on the degree of neutralization, the canopy radius of gyration and molecular crowding at the ionically modified NP surface. The viscosity in NIMs can be directly controlled with the addition of ions that enhance the exchange rate for polymers at the NP surface. These results show that NIMs for many applications can be prepared by controlling the dynamics of the NP interface.

  4. Material Cycles and Chemicals: Dynamic Material Flow Analysis of Contaminants in Paper Recycling

    DEFF Research Database (Denmark)

    Pivnenko, Kostyantyn; Laner, David; Astrup, Thomas Fruergaard

    2016-01-01

    material source-segregation and collection was the least effective strategy for reducing chemical contamination, if the overall recycling rates should be maintained at the current level (approximately 70% for Europe). The study provides a consistent approach for evaluating contaminant levels in material......This study provides a systematic approach for assessment of contaminants in materials for recycling. Paper recycling is used as an illustrative example. Three selected chemicals, bisphenol A (BPA), diethylhexyl phthalate (DEHP) and mineral oil hydrocarbons (MOHs), are evaluated within the paper...... cycle. The approach combines static material flow analysis (MFA) with dynamic material and substance flow modeling. The results indicate that phasing out of chemicals is the most effective measure for reducing chemical contamination. However, this scenario was also associated with a considerable lag...

  5. Effects of material properties on soft contact dynamics

    International Nuclear Information System (INIS)

    Khurshid, A.; Malik, M.A.; Ghafoor, A.

    2009-01-01

    The superiority of deformable human fingertips as compared to hard robot gripper fingers for grasping and manipulation has led to a number of investigations with robot hands employing elastomers or materials such as fluids or powders beneath a membrane at the fingertips. In this paper, to analyze the stability of dynamic control of an object grasped between two soft fingertips through a soft interface using the viscoelastic material between the manipulating fingers and a manipulated object is modeled through bond graph method (BGM). The fingers are made viscoelastic by using springs and dampers. Detailed bond graph modeling (BGM) of the contact phenomenon with two soft-finger contacts considered to be placed against each other on the opposite sides of the grasped object as is generally the case in a manufacturing environment is presented. The stiffness of the springs is exploited in order to achieve the stability in the soft-grasping which includes friction between the soft finger contact surfaces and the object, The paper also analyses stability of dynamic control through a soft interface between a manipulating finger and a manipulated object. It is shown in the paper that the system stability depends on the visco-elastic material properties of the soft interface. Method of root locus is used to analyze this phenomenon. The paper shows how the weight of the object coming downward is controlled by the friction between the fingers and the object during the application of contact forces by varying the damping and the stiffness in the soft finger. (author)

  6. Non-Adiabatic Molecular Dynamics Methods for Materials Discovery

    Energy Technology Data Exchange (ETDEWEB)

    Furche, Filipp [Univ. of California, Irvine, CA (United States); Parker, Shane M. [Univ. of California, Irvine, CA (United States); Muuronen, Mikko J. [Univ. of California, Irvine, CA (United States); Roy, Saswata [Univ. of California, Irvine, CA (United States)

    2017-04-04

    The flow of radiative energy in light-driven materials such as photosensitizer dyes or photocatalysts is governed by non-adiabatic transitions between electronic states and cannot be described within the Born-Oppenheimer approximation commonly used in electronic structure theory. The non-adiabatic molecular dynamics (NAMD) methods based on Tully surface hopping and time-dependent density functional theory developed in this project have greatly extended the range of molecular materials that can be tackled by NAMD simulations. New algorithms to compute molecular excited state and response properties efficiently were developed. Fundamental limitations of common non-linear response methods were discovered and characterized. Methods for accurate computations of vibronic spectra of materials such as black absorbers were developed and applied. It was shown that open-shell TDDFT methods capture bond breaking in NAMD simulations, a longstanding challenge for single-reference molecular dynamics simulations. The methods developed in this project were applied to study the photodissociation of acetaldehyde and revealed that non-adiabatic effects are experimentally observable in fragment kinetic energy distributions. Finally, the project enabled the first detailed NAMD simulations of photocatalytic water oxidation by titania nanoclusters, uncovering the mechanism of this fundamentally important reaction for fuel generation and storage.

  7. Ultrafast dynamic ellipsometry and spectroscopy of laser shocked materials

    Energy Technology Data Exchange (ETDEWEB)

    Mcgrane, Shawn David [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bolme, Cindy B [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Whitley, Von H [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Moore, David S [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2010-01-01

    Shock waves create extreme states of matter with very high pressures, temperatures, and volumetric compressions, at an exceedingly rapid rate of change. We review how to use a beamsplitter and a note card to turn a typical chirp pulse amplified femtosecond laser system into an ultrafast shock dynamics machine. Open scientific questions that can be addressed with such an apparatus are described. We report on the development of several single shot time resolved diagnostics needed to answer these questions. These single shot diagnostics are expected to be broadly applicable to other types of laser ablation experiments. Experimental results measured from shocked material dynamics of several systems are detailed. Finally, we report on progress towards using transient absorption as a measure of electronic excitation and coherent Raman as a picosecond probe of temperature in shock compressed condensed matter.

  8. Shearographic System for Dynamic Analysis of Materials under Heat Stress

    Directory of Open Access Journals (Sweden)

    Nelson A. Correa-Rojas

    2013-11-01

    Full Text Available Shearography is a tool for monitoring and inspecting of structural flaws and imperfections in different types of industrial, automotive and aeronautics applications. It is based on digital correlation of two speckle patterns in two states of interest: with and without load. The technique has the special quality of being very robust against environmental disturbances. We present a shearographic system to analyze the dynamic behavior of the strain that suffers a material in response to changes in temperature throughout the thermal load process.

  9. Dynamically Reconfigurable Metadevice Employing Nanostructured Phase-Change Materials.

    Science.gov (United States)

    Zhu, Zhihua; Evans, Philip G; Haglund, Richard F; Valentine, Jason G

    2017-08-09

    Mastering dynamic free-space spectral control and modulation in the near-infrared (NIR) and optical regimes remains a challenging task that is hindered by the available functional materials at high frequencies. In this work, we have realized an efficient metadevice capable of spectral control by minimizing the thermal mass of a vanadium dioxide phase-change material (PCM) and placing the PCM at the feed gap of a bow-tie field antenna. The device has an experimentally measured tuning range of up to 360 nm in the NIR and a modulation depth of 33% at the resonant wavelength. The metadevice is configured for integrated and local heating, leading to faster switching and more precise spatial control compared with devices based on phase-change thin films. We envisage that the combined advantages of this device will open new opportunities for signal processing, memory, security, and holography at optical frequencies.

  10. Investigation of dynamic fracture behavior in functionally graded materials

    International Nuclear Information System (INIS)

    Yang, X B; Qin, Y P; Zhuang, Z; You, X C

    2008-01-01

    The fast running crack in functionally graded materials (FGMs) is investigated through numerical simulations under impact loading. Some fracture characterizations such as crack propagation and arrest are evaluated by the criterion of the crack tip opening angle. Based on the experimental results, the whole propagation process of the fast running crack is simulated by the finite element program. Thus, the dynamic fracture parameters can be obtained during the crack growing process. In this paper, the crack direction is assumed to be the graded direction of the materials, and the property gradation in FGMs is considered by varying the elastic modulus exponentially along the graded direction and keeping the mass density and Poisson's ratio constant. The influences of the non-homogeneity, the loading ratio and the crack propagation speed on the dynamic fracture response of FGMs are analyzed through the test and numerical analysis. Considering the potential application of FGMs in natural-gas transmission engineering, a functionally graded pipeline is designed to arrest the fast running crack for a short period in high pressure large diameter natural-gas pipelines

  11. Dynamics of crater formations in immersed granular materials

    Science.gov (United States)

    Varas, G.; Vidal, V.; Géminard, J.

    2009-12-01

    Craters are part of the widespread phenomena observed in nature. Among the main applications to natural phenomena, aside from meteorite impact craters, are the formation and growth of volcanic edifices, by successive ejecta emplacement and/or erosion. The time evolution and dynamics play a crucial role here, as the competition between volcanic-jet mass-flux (degassing and ejecta) and crater-size evolution may control directly the eruptive regime. Crater morphology in dry granular material has been extensively studied, both experimentally and theoretically. Most of these studies investigate the final, steady crater shape resulting from the collision of solid bodies with the material surface and scaling laws are derived. In immersed granular material, craters generated by an underwater vortex ring, or underwater impact craters generated by landslide, have been reported. In a previous experimental study, Gostiaux et al. [Gran. Matt., 2002] have investigated the dynamics of air flowing through an immersed granular layer. They reported that, depending on the flow rate, the system exhibits two qualitatively different regimes: At small flow rate, the bubbling regime during which bubbles escape the granular layer independently one from another; At large flow rate, the open-channel regime which corresponds to the formation of a channel crossing the whole thickness of the granular bed through which air escapes almost continuously. At intermediate flow rate, a spontaneous alternation between these two regimes is observed. Here, we report the dynamics of crater formations at the free surface of an immersed granular bed, locally crossed by an ascending gas flow. We reproduce the experimental conditions of Gostiaux et al. (2002) in two dimensions: In a vertical Hele-Shaw cell, the crater consists of two sand piles which develop around the location of the gas emission. We observe that the typical size of the crater increases logarithmically with time, independently of the gas

  12. Review of selected dynamic material control functions for international safeguards

    International Nuclear Information System (INIS)

    Lowry, L.L.

    1980-09-01

    With the development of Dynamic Special Nuclear Material Accounting and Control systems used in nuclear manufacturing and reprocessing plants, there arises the question as to how these systems affect the IAEA inspection capabilities. The systems in being and under development provide information and control for a variety of purposes important to the plant operator, the safeguards purpose being one of them. This report attempts to judge the usefulness of these dynamic systems to the IAEA and have defined 12 functions that provide essential information to it. If the information acquired by these dynamic systems is to be useful to the IAEA, the inspectors must be able to independently verify it. Some suggestions are made as to how this might be done. But, even if it should not be possible to verify all the data, the availability to the IAEA of detailed, simultaneous, and plant-wide information would tend to inhibit a plant operator from attempting to generate a floating or fictitious inventory. Suggestions are made that might be helpful in the design of future software systems, an area which has proved to be fatally deficient in some systems and difficult in all

  13. Stress Distribution in Graded Cellular Materials Under Dynamic Compression

    Directory of Open Access Journals (Sweden)

    Peng Wang

    Full Text Available Abstract Dynamic compression behaviors of density-homogeneous and density-graded irregular honeycombs are investigated using cell-based finite element models under a constant-velocity impact scenario. A method based on the cross-sectional engineering stress is developed to obtain the one-dimensional stress distribution along the loading direction in a cellular specimen. The cross-sectional engineering stress is contributed by two parts: the node-transitive stress and the contact-induced stress, which are caused by the nodal force and the contact of cell walls, respectively. It is found that the contact-induced stress is dominant for the significantly enhanced stress behind the shock front. The stress enhancement and the compaction wave propagation can be observed through the stress distributions in honeycombs under high-velocity compression. The single and double compaction wave modes are observed directly from the stress distributions. Theoretical analysis of the compaction wave propagation in the density-graded honeycombs based on the R-PH (rigid-plastic hardening idealization is carried out and verified by the numerical simulations. It is found that stress distribution in cellular materials and the compaction wave propagation characteristics under dynamic compression can be approximately predicted by the R-PH shock model.

  14. Hierarchical Canopy Dynamics of Electrolyte-Doped Nanoscale Ionic Materials

    KAUST Repository

    Jespersen, Michael L.

    2013-12-23

    Nanoscale ionic materials (NIMs) are organic-inorganic hybrids prepared from ionically functionalized nanoparticles (NP) neutralized by oligomeric polymer counterions. NIMs are designed to behave as liquids under ambient conditions in the absence of solvent and have no volatile organic content, making them useful for a number of applications. We have used nuclear magnetic resonance relaxation and pulsed-field gradient NMR to probe local and collective canopy dynamics in NIMs based on 18-nm silica NPs with a covalently bound anionic corona, neutralized by amine-terminated ethylene oxide/propylene oxide block copolymers. The NMR relaxation studies show that the nanosecond-scale canopy dynamics depend on the degree of neutralization, the canopy radius of gyration, and crowding at the ionically modified NP surface. Two canopy populations are observed in the diffusion experiments, demonstrating that one fraction of the canopy is bound to the NP surface on the time scale (milliseconds) of the diffusion experiment and is surrounded by a more mobile layer of canopy that is unable to access the surface due to molecular crowding. The introduction of electrolyte ions (Na+ or Mg2+) screens the canopy-corona electrostatic interactions, resulting in a reduced bulk viscosity and faster canopy exchange. The magnitude of the screening effect depends upon ion concentration and valence, providing a simple route for tuning the macroscopic properties of NIMs. © 2013 American Chemical Society.

  15. Hierarchical Canopy Dynamics of Electrolyte-Doped Nanoscale Ionic Materials

    KAUST Repository

    Jespersen, Michael L.; Mirau, Peter A.; von Meerwall, Ernst D.; Koerner, Hilmar; Vaia, Richard A.; Fernandes, Nikhil J.; Giannelis, Emmanuel P.

    2013-01-01

    Nanoscale ionic materials (NIMs) are organic-inorganic hybrids prepared from ionically functionalized nanoparticles (NP) neutralized by oligomeric polymer counterions. NIMs are designed to behave as liquids under ambient conditions in the absence of solvent and have no volatile organic content, making them useful for a number of applications. We have used nuclear magnetic resonance relaxation and pulsed-field gradient NMR to probe local and collective canopy dynamics in NIMs based on 18-nm silica NPs with a covalently bound anionic corona, neutralized by amine-terminated ethylene oxide/propylene oxide block copolymers. The NMR relaxation studies show that the nanosecond-scale canopy dynamics depend on the degree of neutralization, the canopy radius of gyration, and crowding at the ionically modified NP surface. Two canopy populations are observed in the diffusion experiments, demonstrating that one fraction of the canopy is bound to the NP surface on the time scale (milliseconds) of the diffusion experiment and is surrounded by a more mobile layer of canopy that is unable to access the surface due to molecular crowding. The introduction of electrolyte ions (Na+ or Mg2+) screens the canopy-corona electrostatic interactions, resulting in a reduced bulk viscosity and faster canopy exchange. The magnitude of the screening effect depends upon ion concentration and valence, providing a simple route for tuning the macroscopic properties of NIMs. © 2013 American Chemical Society.

  16. Standard test method for dynamic tear testing of metallic materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1983-01-01

    1.1 This test method covers the dynamic tear (DT) test using specimens that are 3/16 in. to 5/8 in. (5 mm to 16 mm) inclusive in thickness. 1.2 This test method is applicable to materials with a minimum thickness of 3/16 in. (5 mm). 1.3 The pressed-knife procedure described for sharpening the notch tip generally limits this test method to materials with a hardness level less than 36 HRC. Note 1—The designation 36 HRC is a Rockwell hardness number of 36 on Rockwell C scale as defined in Test Methods E 18. 1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.5 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.

  17. Shear test on viscoelastic granular material using Contact Dynamics simulations

    Science.gov (United States)

    Quezada, Juan Carlos; Sagnol, Loba; Chazallon, Cyrille

    2017-06-01

    By means of 3D contact dynamic simulations, the behavior of a viscoelastic granular material under shear loading is investigated. A viscoelastic fluid phase surrounding the solid particles is simulated by a contact model acting between them. This contact law was implemented in the LMGC90 software, based on the Burgers model. This model is able to simulate also the effect of creep relaxation. To validate the proposed contact model, several direct shear tests were performed, experimentally and numerically using the Leutner device. The numerical samples were created using spheres with two particle size distribution, each one identified for two layers from a road structure. Our results show a reasonable agreement between experimental and numerical data regarding the strain-stress evolution curves and the stress levels measured at failure. The proposed model can be used to simulate the mechanical behavior of multi-layer road structure and to study the influence of traffic on road deformation, cracking and particles pull-out induced by traffic loading.

  18. Cascaded image analysis for dynamic crack detection in material testing

    Science.gov (United States)

    Hampel, U.; Maas, H.-G.

    Concrete probes in civil engineering material testing often show fissures or hairline-cracks. These cracks develop dynamically. Starting at a width of a few microns, they usually cannot be detected visually or in an image of a camera imaging the whole probe. Conventional image analysis techniques will detect fissures only if they show a width in the order of one pixel. To be able to detect and measure fissures with a width of a fraction of a pixel at an early stage of their development, a cascaded image analysis approach has been developed, implemented and tested. The basic idea of the approach is to detect discontinuities in dense surface deformation vector fields. These deformation vector fields between consecutive stereo image pairs, which are generated by cross correlation or least squares matching, show a precision in the order of 1/50 pixel. Hairline-cracks can be detected and measured by applying edge detection techniques such as a Sobel operator to the results of the image matching process. Cracks will show up as linear discontinuities in the deformation vector field and can be vectorized by edge chaining. In practical tests of the method, cracks with a width of 1/20 pixel could be detected, and their width could be determined at a precision of 1/50 pixel.

  19. The application of nonlinear dynamics in the study of ferroelectric materials

    International Nuclear Information System (INIS)

    Blochwitz, S.; Habel, R.; Diestelhorst, M.; Beige, H.

    1996-01-01

    It is well known that the structural phase transitions in ferroelectric materials are connected with strong nonlinear properties. So we can expect all features of nonlinear dynamical systems such as period-doubling cascades and chaos in a dynamical system that contains ferroelectric materials. Therefore we can apply nonlinear dynamics to these ferroelectric materials and we are doing it in two directions: (i) We study the structural phase transitions by analyzing the large signal behaviour with means of nonlinear dynamics. (ii) We control the chaotic behaviour of the system with the method proposed by Ott, Grebogi and Yorke. (authors)

  20. Dynamic Secondary Ion Mass Spectrometry | Materials Science | NREL

    Science.gov (United States)

    Ion Mass Spectrometry (SIMS) uses a continuous, focused beam of primary ions to remove material from the surface of a sample by sputtering. The fraction of sputtered material that is ionized is extracted Identifies all elements or isotopes present in a material, from hydrogen to uranium. Different primary-ion

  1. Towards a dynamic assessment of raw materials criticality: Linking agent-based demand — With material flow supply modelling approaches

    International Nuclear Information System (INIS)

    Knoeri, Christof; Wäger, Patrick A.; Stamp, Anna; Althaus, Hans-Joerg; Weil, Marcel

    2013-01-01

    Emerging technologies such as information and communication-, photovoltaic- or battery technologies are expected to increase significantly the demand for scarce metals in the near future. The recently developed methods to evaluate the criticality of mineral raw materials typically provide a ‘snapshot’ of the criticality of a certain material at one point in time by using static indicators both for supply risk and for the impacts of supply restrictions. While allowing for insights into the mechanisms behind the criticality of raw materials, these methods cannot account for dynamic changes in products and/or activities over time. In this paper we propose a conceptual framework intended to overcome these limitations by including the dynamic interactions between different possible demand and supply configurations. The framework integrates an agent-based behaviour model, where demand emerges from individual agent decisions and interaction, into a dynamic material flow model, representing the materials' stocks and flows. Within the framework, the environmental implications of substitution decisions are evaluated by applying life-cycle assessment methodology. The approach makes a first step towards a dynamic criticality assessment and will enhance the understanding of industrial substitution decisions and environmental implications related to critical metals. We discuss the potential and limitation of such an approach in contrast to state-of-the-art methods and how it might lead to criticality assessments tailored to the specific circumstances of single industrial sectors or individual companies. - Highlights: ► Current criticality assessment methods provide a ‘snapshot’ at one point in time. ► They do not account for dynamic interactions between demand and supply. ► We propose a conceptual framework to overcomes these limitations. ► The framework integrates an agent-based behaviour model with a dynamic material flow model. ► The approach proposed makes

  2. Dynamic material behavior determination using single fiber impact

    NARCIS (Netherlands)

    Heru Utomo, B.D.; Broos, J.P.F.

    2007-01-01

    Mechanical properties of fiber materials are used as input data for amongst others impact simulations on fiber based structures to predict their behavior. Accurate predictions for such materials are still not possible, because the mechanical properties are usually determined (quasi-)statically or

  3. Dynamic materials accounting for solvent-extraction systems

    Energy Technology Data Exchange (ETDEWEB)

    Cobb, D.D.; Ostenak, C.A.

    1979-01-01

    Methods for estimating nuclear materials inventories in solvent-extraction contactors are being developed. These methods employ chemical models and available process measurements. Comparisons of model calculations and experimental data for mixer-settlers and pulsed columns indicate that this approach should be adequate for effective near-real-time materials accounting in nuclear fuels reprocessing plants.

  4. Dynamic materials accounting for solvent-extraction systems

    International Nuclear Information System (INIS)

    Cobb, D.D.; Ostenak, C.A.

    1979-01-01

    Methods for estimating nuclear materials inventories in solvent-extraction contactors are being developed. These methods employ chemical models and available process measurements. Comparisons of model calculations and experimental data for mixer-settlers and pulsed columns indicate that this approach should be adequate for effective near-real-time materials accounting in nuclear fuels reprocessing plants

  5. Towards a dynamic assessment of raw materials criticality: linking agent-based demand--with material flow supply modelling approaches.

    Science.gov (United States)

    Knoeri, Christof; Wäger, Patrick A; Stamp, Anna; Althaus, Hans-Joerg; Weil, Marcel

    2013-09-01

    Emerging technologies such as information and communication-, photovoltaic- or battery technologies are expected to increase significantly the demand for scarce metals in the near future. The recently developed methods to evaluate the criticality of mineral raw materials typically provide a 'snapshot' of the criticality of a certain material at one point in time by using static indicators both for supply risk and for the impacts of supply restrictions. While allowing for insights into the mechanisms behind the criticality of raw materials, these methods cannot account for dynamic changes in products and/or activities over time. In this paper we propose a conceptual framework intended to overcome these limitations by including the dynamic interactions between different possible demand and supply configurations. The framework integrates an agent-based behaviour model, where demand emerges from individual agent decisions and interaction, into a dynamic material flow model, representing the materials' stocks and flows. Within the framework, the environmental implications of substitution decisions are evaluated by applying life-cycle assessment methodology. The approach makes a first step towards a dynamic criticality assessment and will enhance the understanding of industrial substitution decisions and environmental implications related to critical metals. We discuss the potential and limitation of such an approach in contrast to state-of-the-art methods and how it might lead to criticality assessments tailored to the specific circumstances of single industrial sectors or individual companies. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Influence of dynamic material properties on the design criteria of containment structures for fast breeder reactors

    International Nuclear Information System (INIS)

    Albertini, C.; Montagnani, M.

    1978-01-01

    Effects of defects in materials, created by welding processes and irradiation, are examined taking into account the influence of strain-rate. Materials examined are austenitic stainless steels, such as AISI 316 L and H, AISI 304 L. The influence of such parameters on the flow curves of these materials requires the introduction of additional safety coefficients in calculating the response of dynamically loaded structures such as the pressure vessel in the case of an accident. Furthermore the effects of dynamic multi-axial loading and wave propagation should be taken into account in the safety analysis. Running experiments in dynamic biaxial loading conditions are introduced. (author)

  7. Modelling Emission from Building Materials with Computational Fluid Dynamics

    DEFF Research Database (Denmark)

    Topp, Claus; Nielsen, Peter V.; Heiselberg, Per

    This paper presents a numerical model that by means of computational fluid dynamics (CFD) is capable of dealing with both pollutant transport across the boundary layer and internal diffusion in the source without prior knowledge of which is the limiting process. The model provides the concentration...

  8. Dynamic reciprocity in bio-inspired supramolecular materials

    NARCIS (Netherlands)

    Bastings, M.M.C.

    2012-01-01

    Dynamic reciprocity, the spatio-temporal bidirectional process between evolving partners in a functional system is not only found in nature, but also applies to supramolecularly assembling architectures. In this thesis, the focus was on the understanding of nature-inspired supramolecular

  9. Diffusion in energy materials: Governing dynamics from atomistic modelling

    Science.gov (United States)

    Parfitt, D.; Kordatos, A.; Filippatos, P. P.; Chroneos, A.

    2017-09-01

    Understanding diffusion in energy materials is critical to optimising the performance of solid oxide fuel cells (SOFCs) and batteries both of which are of great technological interest as they offer high efficiency for cleaner energy conversion and storage. In the present review, we highlight the insights offered by atomistic modelling of the ionic diffusion mechanisms in SOFCs and batteries and how the growing predictive capability of high-throughput modelling, together with our new ability to control compositions and microstructures, will produce advanced materials that are designed rather than chosen for a given application. The first part of the review focuses on the oxygen diffusion mechanisms in cathode and electrolyte materials for SOFCs and in particular, doped ceria and perovskite-related phases with anisotropic structures. The second part focuses on disordered oxides and two-dimensional materials as these are very promising systems for battery applications.

  10. Molecular Dynamic Simulations of Nanostructured Ceramic Materials on Parallel Computers

    International Nuclear Information System (INIS)

    Vashishta, Priya; Kalia, Rajiv

    2005-01-01

    Large-scale molecular-dynamics (MD) simulations have been performed to gain insight into: (1) sintering, structure, and mechanical behavior of nanophase SiC and SiO2; (2) effects of dynamic charge transfers on the sintering of nanophase TiO2; (3) high-pressure structural transformation in bulk SiC and GaAs nanocrystals; (4) nanoindentation in Si3N4; and (5) lattice mismatched InAs/GaAs nanomesas. In addition, we have designed a multiscale simulation approach that seamlessly embeds MD and quantum-mechanical (QM) simulations in a continuum simulation. The above research activities have involved strong interactions with researchers at various universities, government laboratories, and industries. 33 papers have been published and 22 talks have been given based on the work described in this report

  11. Dynamic material accountancy in an integrated safeguards system

    International Nuclear Information System (INIS)

    Murrell, J.S.

    1979-01-01

    The nuclear material safeguards system at the Portsmouth Gaseous Diffusion Plant is currently being improved. A new material control system will provide computerized monitoring and accountability, and a new physical protection system will provide upgraded perimeter and portal entry monitoring. The control system incorporates remote computer terminals at all processing, transfer and storage areas throughout the plant. Terminal equipment is interfaced to a computer through teletype equipment. A typical terminal transaction would require verification that the particular activity (material movement or process operation) is authorized, identifying the container involved, weighing the container, and then verifying the enrichment with non-destructive assay instrumentation. The system, when fully operational, will provide near real-time accountability for each eight-hour work shift for all items in process. (author)

  12. Dynamic material accountancy in an integrated safeguards system

    International Nuclear Information System (INIS)

    Murrell, J.S.

    1978-01-01

    The nuclear material safeguards system at the Portsmouth Gaseous Diffusion Plant is currently being improved. A new material control system will provide computerized monitoring and accountability, and a new physical protection system will provide upgraded perimeter and portal entry monitoring. The control system incorporates remote computer terminals at all processing, transfer, and storage areas throughout the plant. Terminal equipment is interfaced to a computer through teletype equipment. A typical terminal transaction would require verification that the particular activity (material movement or process operation) is authorized, identifying the container involved, weighing the container, and then verifying the enrichment with non-destructive assay instrumentation. The system, when fully operational, will provide near real-time accountability for each eight-hour work shift for all items in process

  13. Decision analysis for dynamic accounting of nuclear material

    International Nuclear Information System (INIS)

    Shipley, J.P.

    1978-01-01

    Effective materials accounting for special nuclear material in modern fuel cycle facilities will depend heavily on sophisticated data analysis techniques. Decision analysis, which combines elements of estimation theory, decision theory, and systems analysis, is a framework well suited to the development and application of these techniques. Augmented by pattern-recognition tools such as the alarm-sequence chart, decision analysis can be used to reduce errors caused by subjective data evaluation and to condense large collections of data to a smaller set of more descriptive statistics. Application to data from a model plutonium nitrate-to-oxide conversion process illustrates the concepts

  14. Transient computational homogenization for heterogeneous materials under dynamic excitation

    NARCIS (Netherlands)

    Pham, N.K.H.; Kouznetsova, V.; Geers, M.G.D.

    2013-01-01

    This paper presents a novel transient computational homogenization procedure that is suitable for the modelling of the evolution in space and in time of materials with non-steady state microstructure, such as metamaterials. This transient scheme is an extension of the classical (first-order)

  15. Evidence for Effective Uses of Dynamic Visualisations in Science Curriculum Materials

    Science.gov (United States)

    McElhaney, Kevin W.; Chang, Hsin-Yi; Chiu, Jennifer L.; Linn, Marcia C.

    2015-01-01

    Dynamic visualisations capture aspects of scientific phenomena that are difficult to communicate in static materials and benefit from well-designed scaffolds to succeed in classrooms. We review research to clarify the impacts of dynamic visualisations and to identify instructional scaffolds that mediate their success. We use meta-analysis to…

  16. Simulation of the dynamic response of radioactive material shipping package - railcar systems during coupling operations

    International Nuclear Information System (INIS)

    Fields, S.R.

    1981-12-01

    The basic equations of the computer model CARDS (Cask-Railcar Dynamic Simulator), developed for the U.S. Nuclear Regulatory Commission to simulate the dynamic behavior of radioactive material shipping package - railcar systems, are presented. A companion model, CARRS (Casks Railcar Response Spectrum Generator), that generates system response as frequency response spectra is also presented in terms of its basic equations

  17. Simulation of the dynamic response of radioactive material shipping package-railcar systems during coupling operations

    International Nuclear Information System (INIS)

    Fields, S.R.

    1983-10-01

    The basic equations of the computer model CARDS (Cask-Railcar Dynamic Simulator), developed for the US Nuclear Regulatory Commission to simulate the dynamic behavior of radioactive material shipping package - railcar systems, are presented. A companion model, CARRS (Cask Railcar Response Spectrum Generator), that generates system response as frequency response spectra is also presented in terms of its basic equations. 1 reference, 18 figures

  18. Loading technique for dynamic response studies of geological materials

    International Nuclear Information System (INIS)

    Butler, R.I.; Forrestal, M.J.

    1979-04-01

    A loading technique to study the dynamic response of tuff was explored. Loading is provided by electrically exploding etched copper mesh patterns with current from a capacitor discharge. Pressure pulses with peak pressures up to 1.25 kbar and 0.10 to 0.20 ms durations were measured with a pressure bar. The upper value of peak pressure was limited by the strength of the experimental apparatus, and higher pressure generation is possible with a redesign of test hardware. 6 figures, 2 tables

  19. Wave dynamics and composite mechanics for microstructured materials and metamaterials

    CERN Document Server

    2017-01-01

    This volume deals with topical problems concerning technology and design in construction of modern metamaterials. The authors construct the models of mechanical, electromechanical and acoustical behavior of the metamaterials, which are founded upon mechanisms existing on micro-level in interaction of elementary structures of the material. The empiric observations on the phenomenological level are used to test the created models. The book provides solutions, based on fundamental methods and models using the theory of wave propagation, nonlinear theories and composite mechanics for media with micro- and nanostructure. They include the models containing arrays of cracks, defects, with presence of micro- and nanosize piezoelectric elements and coupled physical-mechanical fields of different nature. The investigations show that the analytical, numerical and experimental methods permit evaluation of the qualitative and quantitative properties of the materials of this sort, with diagnosis of their effective characte...

  20. Dynamic High-Pressure Behavior of Hierarchical Heterogeneous Geological Materials

    Science.gov (United States)

    2016-04-01

    plate-impact experiments. The peak stress, particle velocity, or shock velocity, are measured using point diagnostics employing either stress gauges or...and porous geological materials. In this prior work, they obtained the Hugoniot states for a 60:40 volumetric mixture of ice and sand [8], to...in copper capsule, backed with PMMA. The instrumentation includes two PVDF stress gauges , VISAR, and ToA shorting pins. 44mm ø ~5mm thick sample

  1. Attosecond Electron Processes in Materials: Excitons, Plasmons, and Charge Dynamics

    Science.gov (United States)

    2015-05-19

    focused using a f=1.5 m lens into a 250 micron hollow core fiber (HCF) filled with neon gas at atmospheric pressure to stretch the pulse spectrum from... insulator to metal transition. Introduction: The goal of this work was to understand the generation, transport, and manipulation of electronic charge...chemically sensitive probe pulse utilizing specific core level transitions in atoms that are part of a material under study. The measurements follow

  2. Dynamic Response of Coarse Granular Material to Wave Load

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo

    1998-01-01

    The soil beneath vertical breakwaters is subjected to a combination of forces induced by the waves. The forces acting on the soil can be characterized as 1) static load due to submerged weight of the structure, 2) quasi-static forces induced by cyclic wave loading, and 3) wave impact from breaking...... waves. The stress conditions in the soil below a foundation exposed to these types of loading are very complex. The key to explain and quantify the soil response beneath a vertical breakwater is to understand the role of the volume changes and to be able to model these correctly. It is shown...... that the volume changes in soil subjected to static and dynamic loading are controlled by the characteristic line. Experiments have been performed to study the factors that influence the location of the characteristic line in drained and undrained tests for various types of sand and various types of loading...

  3. Computational dynamics of laser alloyed metallic materials for improved corrosion performance: computational dynamics of laser alloyed metallic materials

    CSIR Research Space (South Africa)

    Fatoba, OS

    2016-04-01

    Full Text Available Laser alloying is a material processing method which utilizes the high power density available from defocused laser beam to melt both metal coatings and a part of the underlying substrate. Since melting occur solitary at the surface, large...

  4. Determination of dynamic fracture initiation toughness of elastic-plastic materials at intermediate strain rates

    International Nuclear Information System (INIS)

    Fernandez-Saez, J.; Luna de, S.; Rubio, L.; Perez-Castellanos, J. L.; Navarro, C.

    2001-01-01

    An earlier paper dealt with the experimental techniques used to determine the dynamic fracture properties of linear elastic materials. Here we describe those most commonly used as elastoplastic materials, limiting the study to the initiation fracture toughness at the intermediate strain rate (of around 10''2 s''-1). In this case the inertial forces are negligible and it is possible to apply the static solutions. With this stipulation, the analysis can be based on the methods of testing in static conditions. The dynamic case differs basically, from the static one, in the influence of the strain rate on the properties of the material. (Author) 57 refs

  5. A dynamic material discrimination algorithm for dual MV energy X-ray digital radiography

    International Nuclear Information System (INIS)

    Li, Liang; Li, Ruizhe; Zhang, Siyuan; Zhao, Tiao; Chen, Zhiqiang

    2016-01-01

    Dual-energy X-ray radiography has become a well-established technique in medical, industrial, and security applications, because of its material or tissue discrimination capability. The main difficulty of this technique is dealing with the materials overlapping problem. When there are two or more materials along the X-ray beam path, its material discrimination performance will be affected. In order to solve this problem, a new dynamic material discrimination algorithm is proposed for dual-energy X-ray digital radiography, which can also be extended to multi-energy X-ray situations. The algorithm has three steps: α-curve-based pre-classification, decomposition of overlapped materials, and the final material recognition. The key of the algorithm is to establish a dual-energy radiograph database of both pure basis materials and pair combinations of them. After the pre-classification results, original dual-energy projections of overlapped materials can be dynamically decomposed into two sets of dual-energy radiographs of each pure material by the algorithm. Thus, more accurate discrimination results can be provided even with the existence of the overlapping problem. Both numerical and experimental results that prove the validity and effectiveness of the algorithm are presented. - Highlights: • A material discrimination algorithm for dual MV energy X-ray digital radiography is proposed. • To solve the materials overlapping problem of the current dual energy algorithm. • The experimental results with the 4/7 MV container inspection system are shown.

  6. Studies of dynamic and static leaching of cemented and uncemented sorption material loaded with iodine-129

    International Nuclear Information System (INIS)

    Furrer, J.

    1989-05-01

    Leaching tests with water and brines were conducted on AC 6120 iodine sorption material (12 wt.% Ag) in order to improve the assessment of the behaviour of radioactive waste stored in a repository mine (salt or iron ore). As a result of the dynamic and static leaching tests, the leached fraction of I-129 in the uncemented material was found to be -1 %, while that of the cemented iodine sorption material was found to be -2 %. After ordinary steel had been added to the cemented sorption material, the leached fractions found were identical to those measured in uncemented material. The addition of stainless steel had only little influence on the leached fraction. (author)

  7. Multiscale Modeling using Molecular Dynamics and Dual Domain Material Point Method

    Energy Technology Data Exchange (ETDEWEB)

    Dhakal, Tilak Raj [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division. Fluid Dynamics and Solid Mechanics Group, T-3; Rice Univ., Houston, TX (United States)

    2016-07-07

    For problems involving large material deformation rate, the material deformation time scale can be shorter than the material takes to reach a thermodynamical equilibrium. For such problems, it is difficult to obtain a constitutive relation. History dependency become important because of thermodynamic non-equilibrium. Our goal is to build a multi-scale numerical method which can bypass the need for a constitutive relation. In conclusion, multi-scale simulation method is developed based on the dual domain material point (DDMP). Molecular dynamics (MD) simulation is performed to calculate stress. Since the communication among material points is not necessary, the computation can be done embarrassingly parallel in CPU-GPU platform.

  8. Analysis of the material configurations and influence on the dynamic response

    Directory of Open Access Journals (Sweden)

    Murčinková Zuzana

    2018-01-01

    Full Text Available The paper presents the analysis of the material configuration of composites based on the measurement of their dynamic response. The article presents the measurement scheme, the design of the measuring stand together with the analysis of the results. Moreover, it analyses the FFT spectrums of layered long fibre composite, short fibre composites of different fibres materials and homogeneous materials as steel and aluminium alloy.

  9. Materials compatibility issues related to thermal energy storage for a space solar dynamic power system

    Science.gov (United States)

    Faget, N. M.

    1986-01-01

    Attention is given to results obtained to date in developmental investigations of a thermal energy storage (TES) system for the projected NASA Space Station's solar dynamic power system; these tests have concentrated on issues related to materials compatibility for phase change materials (PCMs) and their containment vessels' materials. The five PCMs tested have melting temperatures that correspond to the operating temperatures of either the Brayton or Rankine heat engines, which were independently chosen for their high energy densities.

  10. Final Report: Nanoscale Dynamical Heterogeneity in Complex Magnetic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Kevan, Stephen [Univ. of Oregon, Eugene, OR (United States)

    2016-05-27

    A magnetic object can be demagnetized by dropping it on a hard surface, but what does ‘demagnetized’ actually mean? In 1919 Heinrich Barkhausen proved the existence of magnetic domains, which are regions of uniform magnetization that are much larger than atoms but much smaller than a macroscopic object. A material is fully magnetized when domain magnetizations are aligned, while it is demagnetized when the domain magnetizations are randomly oriented and the net magnetization is zero. The heterogeneity of a demagnetized object leads to interesting questions. Magnets are unstable when their poles align, and stable when their poles anti-align, so why is the magnetized state ever stable? What do domains look like? What is the structure of a domain wall? How does the magnetized state transform to the demagnetized state? How do domains appear and disappear? What are the statistical properties of domains and how do these vary as the domain pattern evolves? Some of these questions remain the focus of intense study nearly a century after Barkhausen’s discovery. For example, just a few years ago a new kind of magnetic texture called a skyrmion was discovered. A skyrmion is a magnetic domain that is a nanometer-scale, topologically protected vortex. ‘Topologically protected’ means that skyrmions are hard to destroy and so are stable for extended periods. Skyrmions are characterized by integral quantum numbers and are observed to move with little dissipation and so could store and process information with very low power input. Our research project uses soft x-rays, which offer very high magnetic contrast, to probe magnetic heterogeneity and to measure how it evolves in time under external influences. We will condition a soft x-ray beam so that the wave fronts will be coherent, that is, they will be smooth and well-defined. When coherent soft x-ray beam interacts with a magnetic material, the magnetic heterogeneity is imprinted onto the wave fronts and projected into

  11. Evidence on dynamic effects in the water content – water potential relation of building materials

    DEFF Research Database (Denmark)

    Scheffler, Gregor Albrecht; Plagge, Rudolf

    2008-01-01

    static and dynamic moisture storage data and the more pronounced was the corresponding dynamic hysteresis. The paper thus provides clear experimental evidence on dynamic effects in the water content – water potential relation of building materials. By that, data published by previous authors as Topp et......Hygrothermal simulation has become a widely applied tool for the design and assessment of building structures under possible indoor and outdoor climatic conditions. One of the most important prerequisites of such simulations is reliable material data. Different approaches exist here to derive...... the required material functions, i.e. the moisture storage characteristic and the liquid water conductivity, from measured basic properties. The current state of the art in material modelling as well as the corresponding transport theory implies that the moisture transport function is unique...

  12. Liquid metal batteries - materials selection and fluid dynamics

    Science.gov (United States)

    Weier, T.; Bund, A.; El-Mofid, W.; Horstmann, G. M.; Lalau, C.-C.; Landgraf, S.; Nimtz, M.; Starace, M.; Stefani, F.; Weber, N.

    2017-07-01

    Liquid metal batteries are possible candidates for massive and economically feasible large-scale stationary storage and as such could be key components of future energy systems based mainly or exclusively on intermittent renewable electricity sources. The completely liquid interior of liquid metal batteries and the high current densities give rise to a multitude of fluid flow phenomena that will primarily influence the operation of future large cells, but might be important for today’s smaller cells as well. The paper at hand starts with a discussion of the relative merits of using molten salts or ionic liquids as electrolytes for liquid metal cells and touches the choice of electrode materials. This excursus into electrochemistry is followed by an overview of investigations on magnetohydrodynamic instabilities in liquid metal batteries, namely the Tayler instability and electromagnetically excited gravity waves. A section on electro-vortex flows complements the discussion of flow phenomena. Focus of the flow related investigations lies on the integrity of the electrolyte layer and related critical parameters.

  13. Mapping Carrier Dynamics on Material Surfaces in Space and Time using Scanning Ultrafast Electron Microscopy

    KAUST Repository

    Sun, Jingya

    2016-02-25

    Selectively capturing the ultrafast dynamics of charge carriers on materials surfaces and at interfaces is crucial to the design of solar cells and optoelectronic devices. Despite extensive research efforts over the past few decades, information and understanding about surface-dynamical processes, including carrier trapping and recombination remains extremely limited. A key challenge is to selectively map such dynamic processes, a capability that is hitherto impractical by time-resolved laser techniques, which are limited by the laser’s relatively large penetration depth and consequently they record mainly bulk information. Such surface dynamics can only be mapped in real space and time by applying four-dimensional (4D) scanning ultrafast electron microscopy (S-UEM), which records snapshots of materials surfaces with nanometer spatial and sub-picosecond temporal resolutions. In this method, the secondary electron (SE) signal emitted from the sample’s surface is extremely sensitive to the surface dynamics and is detected in real time. In several unique applications, we spatially and temporally visualize the SE energy gain and loss, the charge carrier dynamics on the surface of InGaN nanowires and CdSe single crystals and its powder film. We also provide the mechanisms for the observed dynamics, which will be the foundation for future potential applications of S-UEM to a wide range of studies on material surfaces and device interfaces.

  14. Mapping Carrier Dynamics on Material Surfaces in Space and Time using Scanning Ultrafast Electron Microscopy

    KAUST Repository

    Sun, Jingya; Adhikari, Aniruddha; Shaheen, Basamat; Yang, Haoze; Mohammed, Omar F.

    2016-01-01

    Selectively capturing the ultrafast dynamics of charge carriers on materials surfaces and at interfaces is crucial to the design of solar cells and optoelectronic devices. Despite extensive research efforts over the past few decades, information and understanding about surface-dynamical processes, including carrier trapping and recombination remains extremely limited. A key challenge is to selectively map such dynamic processes, a capability that is hitherto impractical by time-resolved laser techniques, which are limited by the laser’s relatively large penetration depth and consequently they record mainly bulk information. Such surface dynamics can only be mapped in real space and time by applying four-dimensional (4D) scanning ultrafast electron microscopy (S-UEM), which records snapshots of materials surfaces with nanometer spatial and sub-picosecond temporal resolutions. In this method, the secondary electron (SE) signal emitted from the sample’s surface is extremely sensitive to the surface dynamics and is detected in real time. In several unique applications, we spatially and temporally visualize the SE energy gain and loss, the charge carrier dynamics on the surface of InGaN nanowires and CdSe single crystals and its powder film. We also provide the mechanisms for the observed dynamics, which will be the foundation for future potential applications of S-UEM to a wide range of studies on material surfaces and device interfaces.

  15. Exploiting Fission Chain Reaction Dynamics to Image Fissile Materials

    Science.gov (United States)

    Chapman, Peter Henry

    Radiation imaging is one potential method to verify nuclear weapons dismantlement. The neutron coded aperture imager (NCAI), jointly developed by Oak Ridge National Laboratory (ORNL) and Sandia National Laboratories (SNL), is capable of imaging sources of fast (e.g., fission spectrum) neutrons using an array of organic scintillators. This work presents a method developed to discriminate between non-multiplying (i.e., non-fissile) neutron sources and multiplying (i.e., fissile) neutron sources using the NCAI. This method exploits the dynamics of fission chain-reactions; it applies time-correlated pulse-height (TCPH) analysis to identify neutrons in fission chain reactions. TCPH analyzes the neutron energy deposited in the organic scintillator vs. the apparent neutron time-of-flight. Energy deposition is estimated from light output, and time-of-flight is estimated from the time between the neutron interaction and the immediately preceding gamma interaction. Neutrons that deposit more energy than can be accounted for by their apparent time-of-flight are identified as fission chain-reaction neutrons, and the image is reconstructed using only these neutron detection events. This analysis was applied to measurements of weapons-grade plutonium (WGPu) metal and 252Cf performed at the Nevada National Security Site (NNSS) Device Assembly Facility (DAF) in July 2015. The results demonstrate it is possible to eliminate the non-fissile 252Cf source from the image while preserving the fissileWGPu source. TCPH analysis was also applied to additional scenes in which theWGPu and 252Cf sources were measured individually. The results of these separate measurements further demonstrate the ability to remove the non-fissile 252Cf source and retain the fissileWGPu source. Simulations performed using MCNPX-PoliMi indicate that in a one hour measurement, solid spheres ofWGPu are retained at a 1sigma level for neutron multiplications M -˜ 3.0 and above, while hollowWGPu spheres are

  16. Dynamic Deformation Behavior of Soft Material Using Shpb Technique and Pulse Shaper

    Science.gov (United States)

    Lee, Ouk Sub; Cho, Kyu Sang; Kim, Sung Hyun; Han, Yong Hwan

    This paper presents a modified Split Hopkinson Pressure Bar (SHPB) technique to obtain compressive stress strain data for NBR rubber materials. An experimental technique with a modified the conventional SHPB has been developed for measuring the compressive stress strain responses of materials with low mechanical impedance and low compressive strengths, such as the rubber and the polymeric material. This paper uses an aluminum pressure bar to achieve a closer impedance match between the pressure bar and the specimen materials. In addition, a pulse shaper is utilized to lengthen the rising time of the incident pulse to ensure dynamic stress equilibrium and homogeneous deformation of NBR rubber materials. It is found that the modified technique can determine the dynamic deformation behavior of rubbers more accurately.

  17. Simultaneous Contact Sensing and Characterizing of Mechanical and Dynamic Heat Transfer Properties of Porous Polymeric Materials

    Directory of Open Access Journals (Sweden)

    Bao-guo Yao

    2017-10-01

    Full Text Available Porous polymeric materials, such as textile fabrics, are elastic and widely used in our daily life for garment and household products. The mechanical and dynamic heat transfer properties of porous polymeric materials, which describe the sensations during the contact process between porous polymeric materials and parts of the human body, such as the hand, primarily influence comfort sensations and aesthetic qualities of clothing. A multi-sensory measurement system and a new method were proposed to simultaneously sense the contact and characterize the mechanical and dynamic heat transfer properties of porous polymeric materials, such as textile fabrics in one instrument, with consideration of the interactions between different aspects of contact feels. The multi-sensory measurement system was developed for simulating the dynamic contact and psychological judgment processes during human hand contact with porous polymeric materials, and measuring the surface smoothness, compression resilience, bending and twisting, and dynamic heat transfer signals simultaneously. The contact sensing principle and the evaluation methods were presented. Twelve typical sample materials with different structural parameters were measured. The results of the experiments and the interpretation of the test results were described. An analysis of the variance and a capacity study were investigated to determine the significance of differences among the test materials and to assess the gage repeatability and reproducibility. A correlation analysis was conducted by comparing the test results of this measurement system with the results of Kawabata Evaluation System (KES in separate instruments. This multi-sensory measurement system provides a new method for simultaneous contact sensing and characterizing of mechanical and dynamic heat transfer properties of porous polymeric materials.

  18. Nondestructive assay technology and in-plant dynamic materials control: ''DYMAC''

    International Nuclear Information System (INIS)

    Keppin, G.R.; Maraman, W.J.

    1975-01-01

    An advanced system of in-plant materials control known as DYMAC, Dynamic Materials Control, is being developed. This major safeguards R and D effort merges state-of-the-art nondestructive assay instrumentation and computer technology, with the clear objective of demonstrating a workable, cost-effective system of stringent, real time control of nuclear materials in a modern plutonium processing facility. Emphasis is placed on developing practical solutions to generic problems of materials measurement and control, so that resulting safeguards techniques and instrumentation will have widespread applicability throughout the nuclear community. (auth)

  19. Experimental study of dynamic effects in moisture transfer in building materials

    DEFF Research Database (Denmark)

    Janssen, Hans; Scheffler, Gregor Albrecht; Plagge, Rudolf

    2016-01-01

    transfer in building materials, similar to moisture transfer in soils, is not free of dynamic effects. The findings imply that the widely accepted static theory for moisture storage in porous media is not generally valid and should be corrected for the occurrences of dynamic effects. Considering......In relation to moisture storage in porous materials, it is often assumed that the process dynamics do not affect the moisture retention. There is mounting evidence though that this notion is incorrect: various studies demonstrate that the moisture retention is influenced by the (de)saturation rates...... of the moisture transfer processes involved. The available evidence primarily stems from imbibition and drainage experiments on soils however, and compared to many other porous media, these tests consider rather permeable materials with relatively dominant liquid transport at comparatively large (de...

  20. PREFACE: International Symposium on Dynamic Deformation and Fracture of Advanced Materials (D2FAM 2013)

    Science.gov (United States)

    Silberschmidt, Vadim V.

    2013-07-01

    Intensification of manufacturing processes and expansion of usability envelopes of modern components and structures in many cases result in dynamic loading regimes that cannot be resented adequately employing quasi-static formulations of respective problems of solid mechanics. Specific features of dynamic deformation, damage and fracture processes are linked to various factors, most important among them being: a transient character of load application; complex scenarios of propagation, attenuation and reflection of stress waves in real materials, components and structures; strain-rate sensitivity of materials properties; various thermo-mechanical regimes. All these factors make both experimental characterisation and theoretical (analytical and numerical) analysis of dynamic deformation and fracture rather challenging; for instance, besides dealing with a spatial realisation of these processes, their evolution with time should be also accounted for. To meet these challenges, an International Symposium on Dynamic Deformation and Fracture of Advanced Materials D2FAM 2013 was held on 9-11 September 2013 in Loughborough, UK. Its aim was to bring together specialists in mechanics of materials, applied mathematics, physics, continuum mechanics, materials science as well as various areas of engineering to discuss advances in experimental and theoretical analysis, and numerical simulations of dynamic mechanical phenomena. Some 50 papers presented at the Symposium by researchers from 12 countries covered various topics including: high-strain-rate loading and deformation; dynamic fracture; impact and blast loading; high-speed penetration; impact fatigue; damping properties of advanced materials; thermomechanics of dynamic loading; stress waves in micro-structured materials; simulation of failure mechanisms and damage accumulation; processes in materials under dynamic loading; a response of components and structures to harsh environment. The materials discussed at D2FAM 2013

  1. Static and Dynamic Friction Behavior of Candidate High Temperature Airframe Seal Materials

    Science.gov (United States)

    Dellacorte, C.; Lukaszewicz, V.; Morris, D. E.; Steinetz, B. M.

    1994-01-01

    The following report describes a series of research tests to evaluate candidate high temperature materials for static to moderately dynamic hypersonic airframe seals. Pin-on-disk reciprocating sliding tests were conducted from 25 to 843 C in air and hydrogen containing inert atmospheres. Friction, both dynamic and static, was monitored and serves as the primary test measurement. In general, soft coatings lead to excessive static friction and temperature affected friction in air environments only.

  2. Dynamic analysis to establish normal shock and vibration of radioactive material shipping packages

    International Nuclear Information System (INIS)

    Fields, S.R.

    1980-01-01

    A computer model, CARDS (Cask-Railcar Dynamic Simulator) was developed to provide input data for a broad range of radioactive material package-tiedown structural assessments. CARDS simulates the dynamic behavior of shipping packages and their transporters during normal transport conditions. The model will be used to identify parameters which significantly affect the normal shock and vibration environments which, in turn, provide the basis for determining the forces transmitted to the packages

  3. 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.

  4. Test methods for the dynamic mechanical properties of polymeric materials. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Baker, G.K.

    1980-06-01

    Various test geometries and procedures for the dynamic mechanical analysis of polymers employing a mechanical spectrometer have been evaluated. The methods and materials included in this work are forced torsional pendulum testing of Kevlar/epoxy laminates and rigid urethane foams, oscillatory parallel plate testing to determine the kinetics of the cure of VCE with Hylene MP, oscillatory compressive testing of B-3223 cellular silicone, and oscillatory tensile testing of Silastic E and single Kevlar filaments. Fundamental dynamic mechanical properties, including the storage and loss moduli and loss tangent of the materials tested, were determined as a function of temperature and sometimes of frequency.

  5. Molecular dynamics simulations of disordered materials from network glasses to phase-change memory alloys

    CERN Document Server

    Massobrio, Carlo; Bernasconi, Marco; Salmon, Philip S

    2015-01-01

    This book is a unique reference work in the area of atomic-scale simulation of glasses. For the first time, a highly selected panel of about 20 researchers provides, in a single book, their views, methodologies and applications on the use of molecular dynamics as a tool to describe glassy materials. The book covers a wide range of systems covering ""traditional"" network glasses, such as chalcogenides and oxides, as well as glasses for applications in the area of phase change materials. The novelty of this work is the interplay between molecular dynamics methods (both at the classical and firs

  6. Uncertainty Quantification in Experimental Structural Dynamics Identification of Composite Material Structures

    DEFF Research Database (Denmark)

    Luczak, Marcin; Peeters, Bart; Kahsin, Maciej

    2014-01-01

    for uncertainty evaluation in experimentally estimated models. Investigated structures are plates, fuselage panels and helicopter main rotor blades as they represent different complexity levels ranging from coupon, through sub-component up to fully assembled structures made of composite materials. To evaluate......Aerospace and wind energy structures are extensively using components made of composite materials. Since these structures are subjected to dynamic environments with time-varying loading conditions, it is important to model their dynamic behavior and validate these models by means of vibration...

  7. Elastic Characterization of Transversely Isotropic Soft Materials by Dynamic Shear and Asymmetric Indentation

    OpenAIRE

    Namani, R.; Feng, Y.; Okamoto, R. J.; Jesuraj, N.; Sakiyama-Elbert, S. E.; Genin, G. M.; Bayly, P. V.

    2012-01-01

    The mechanical characterization of soft anisotropic materials is a fundamental challenge because of difficulties in applying mechanical loads to soft matter and the need to combine information from multiple tests. A method to characterize the linear elastic properties of transversely isotropic soft materials is proposed, based on the combination of dynamic shear testing (DST) and asymmetric indentation. The procedure was demonstrated by characterizing a nearly incompressible transversely isot...

  8. A simple sizing optimization technique for an impact limiter based on dynamic material properties

    International Nuclear Information System (INIS)

    Choi, Woo-Seok; Seo, Ki-Seog

    2010-01-01

    According to IAEA regulations, a transportation package for radioactive material should perform its intended function of containing the radioactive contents after a drop test, which is one of the hypothetical accident conditions. Impact limiters attached to a transport cask absorb most of the impact energy. So, it is important to determine the shape, size and material of impact limiters properly. The material data needed in this determination is a dynamic one. In this study, several materials considered as those of impact limiters were tested by drop weight equipment to acquire the dynamic material characteristics data. The impact absorbing volume of the impact limiter was derived mathematically for each drop condition. A size optimization of the impact limiter was conducted. The derived impact absorbing volumes were applied as constraints. These volumes should be less than the critical volumes generated based on the dynamic material characteristics. The derived procedure to decide the shape of the impact limiter can be useful at the preliminary design stage when the transportation package's outline is roughly determined and applied as an input value.

  9. Dynamic magnetization models for soft ferromagnetic materials with coarse and fine domain structures

    Energy Technology Data Exchange (ETDEWEB)

    Zirka, S.E., E-mail: zirka@email.dp.ua [Department of Physics and Technology, Dnepropetrovsk National University, Gagarin 72, 49050 Dnepropetrovsk (Ukraine); Moroz, Y.I. [Department of Physics and Technology, Dnepropetrovsk National University, Gagarin 72, 49050 Dnepropetrovsk (Ukraine); Steentjes, S.; Hameyer, K. [Institute of Electrical Machines, RWTH Aachen University, Schinkelstr. 4, 52056 Aachen (Germany); Chwastek, K. [Faculty of Electrical Engineering, Czestochowa University of Technology, al. AK 17, 42-201 Czestochowa (Poland); Zurek, S. [Megger Instruments Ltd., Archcliffe Road, Dover, Kent, CT17 9EN (United Kingdom); Harrison, R.G. [Department of Electronics, Carleton University, Ottawa, Canada K1S 5B6 (Canada)

    2015-11-15

    We consider dynamic models, both numerical and analytical, that reproduce the magnetization field H(B) and the energy loss in ferromagnetic sheet materials with different domain structures. Conventional non-oriented (NO) and grain-oriented (GO) electrical steels are chosen as typical representatives of fine-domain and coarse-domain materials. The commonly-accepted loss separation procedures in these materials are critically analyzed. The use of a well-known simplified (“classical”) expression for the eddy-current loss is identified as the primary source of mistaken evaluations of excess loss in NO steel, in which the loss components can only be evaluated using the Maxwell (penetration) equation. The situation is quite different in GO steel, in which the loss separation is uncertain, but the total dynamic loss is several times higher than that explained by any version (numerical or analytical) of the classical approach. To illustrate the uncertainty of the loss separation in GO steel, we show that the magnetization field, and thus the total loss, in this material can be represented with equal accuracy using either the existing three-component approach or our proposed two-component technique, which makes no distinction between classical eddy-current and excess fields and losses. - Highlights: • Critical analysis of a ferromagnetic-material loss-separation principle. • This is to warn materials-science engineers about the inaccuracies resulting from this principle. • A transient model having a single dynamic component is proposed.

  10. Non-equilibrium dynamics in disordered materials: Ab initio molecular dynamics simulations

    International Nuclear Information System (INIS)

    Ohmura, Satoshi; Nagaya, Kiyonobu; Yao, Makoto; Shimojo, Fuyuki

    2015-01-01

    The dynamic properties of liquid B 2 O 3 under pressure and highly-charged bromophenol molecule are studied by using molecular dynamics (MD) simulations based on density functional theory (DFT). Diffusion properties of covalent liquids under high pressure are very interesting in the sense that they show unexpected pressure dependence. It is found from our simulation that the magnitude relation of diffusion coefficients for boron and oxygen in liquid B 2 O 3 shows the anomalous pressure dependence. The simulation clarified the microscopic origin of the anomalous diffusion properties. Our simulation also reveals the dissociation mechanism in the coulomb explosion of the highly-charged bromophenol molecule. When the charge state n is 6, hydrogen atom in the hydroxyl group dissociates at times shorter than 20 fs while all hydrogen atoms dissociate when n is 8. After the hydrogen dissociation, the carbon ring breaks at about 100 fs. There is also a difference on the mechanism of the ring breaking depending on charge states, in which the ring breaks with expanding (n = 6) or shrink (n = 8)

  11. Evaluation of alternative phase change materials for energy storage in solar dynamic applications

    Science.gov (United States)

    Crane, R. A.; Dustin, M. O.

    1988-01-01

    The performance of fluoride salt and metallic thermal energy storage materials are compared in terms of basic performance as applied to solar dynamic power generation. Specific performance considerations include uniformity of cycle inlet temperature, peak cavity temperature, TES utilization, and system weights. Also investigated were means of enhancing the thermal conductivity of the salts and its effect on the system performance.

  12. Molecular dynamics simulations of melting behavior of alkane as phase change materials slurry

    International Nuclear Information System (INIS)

    Rao Zhonghao; Wang Shuangfeng; Wu Maochun; Zhang Yanlai; Li Fuhuo

    2012-01-01

    Highlights: ► The melting behavior of phase change materials slurry was investigated by molecular dynamics simulation method. ► Four different PCM slurry systems including pure water and water/n-nonadecane composite were constructed. ► Amorphous structure and periodic boundary conditions were used in the molecular dynamics simulations. ► The simulated melting temperatures are very close to the published experimental values. - Abstract: The alkane based phase change materials slurry, with high latent heat storage capacity, is effective to enhance the heat transfer rate of traditional fluid. In this paper, the melting behavior of composite phase change materials slurry which consists of n-nonadecane and water was investigated by using molecular dynamics simulation. Four different systems including pure water and water/n-nonadecane composite were constructed with amorphous structure and periodic boundary conditions. The results showed that the simulated density and melting temperature were very close to the published experimental values. Mixing the n-nonadecane into water decreased the mobility but increased the energy storage capacity of composite systems. To describe the melting behavior of alkane based phase change materials slurry on molecular or atomic scale, molecular dynamics simulation is an effective method.

  13. Simulant-material experimental investigation of flow dynamics in the CRBR Upper-Core Structure

    International Nuclear Information System (INIS)

    Wilhelm, D.; Starkovich, V.S.; Chapyak, E.J.

    1982-09-01

    The results of a simulant-material experimental investigation of flow dynamics in the Clinch River Breeder Reactor (CRBR) Upper Core Structure are described. The methodology used to design the experimental apparatus and select test conditions is detailed. Numerous comparisons between experimental data and SIMMER-II Code calculations are presented with both advantages and limitations of the SIMMER modeling features identified

  14. In situ nuclear magnetic resonance study of defect dynamics during deformation of materials

    NARCIS (Netherlands)

    Murty, K.L.; Detemple, K.; Kanert, O.; Peters, G; de Hosson, J.T.M.

    1996-01-01

    Nuclear magnetic resonance techniques can be used to monitor in situ the dynamical behaviour of point and line defects in materials during deformation. These techniques are non-destructive and non-invasive. We report here the atomic transport, in particular the enhanced diffusion during deformation

  15. Paradoxical differences in N-dynamics between Luxembourg soils: litter quality or parent material?

    NARCIS (Netherlands)

    Kooijman, A.M.; Smit, A.

    2009-01-01

    To explore whether litter quality could alter differences in N-dynamics between soil types, we compared spruce and beech growing on soils with parent material sandstone and limestone, and beech and hornbeam on acid marl and limestone. We measured pH, organic matter content, C:N ratio, soil

  16. Paradoxical differences in N-dynamics between Luxembourg soils: Litter quality or parent material?

    NARCIS (Netherlands)

    Kooijman, A.M.; Smit, A.

    2009-01-01

    To explore whether litter quality could alter differences in N-dynamics between soil types, we compared spruce and beech growing on soils with parent material sandstone and limestone, and beech and hornbeam on acid marl and limestone. We measured pH, organic matter content, C:N ratio, soil

  17. Dynamic Material Removal Rate and Tool Replacement Optimization with Calculus of Variations

    Science.gov (United States)

    Lan, Tian-Syung; Lo, Chih-Yao; Chiu, Min-Chie; Yeh, Long-Jyi

    This study mathematically presents an optimum material removal control model, where the Material Removal Rate (MRR) is comprehensively introduced, to accomplish the dynamic machining control and tool life determination of a cutting tool under an expected machining quantity. To resolve the incessant cutting-rate control problem, Calculus of Variations is implemented for the optimum solution. Additionally, the decision criteria for selecting the dynamic solution are suggested and the sensitivity analyses for key variables in the optimal solution are fully discussed. The versatility of this study is furthermore exemplified through a numerical illustration from the real-world industry with BORLAND C++ BUILDER. It is shown that the theoretical and simulated results are in good agreement. This study absolutely explores the very promising solution to dynamically organize the MRR in minimizing the machining cost of a cutting tool for the contemporary machining industry.

  18. Discussion on Application of Space Materials and Technological Innovation in Dynamic Fashion Show

    Science.gov (United States)

    Huo, Meilin; Kim, Chul Soo; Zhao, Wenhan

    2018-03-01

    In modern dynamic fashion show, designers often use the latest ideas and technology, and spend their energy in stage effect and overall environment to make audience’s watching a fashion show like an audio-visual feast. With rapid development of China’s science and technology, it has become a design trend to strengthen the relationship between new ideas, new trends and technology in modern art. With emergence of new technology, new methods and new materials, designers for dynamic fashion show stage art can choose the materials with an increasingly large scope. Generation of new technology has also made designers constantly innovate the stage space design means, and made the stage space design innovated constantly on the original basis of experiences. The dynamic clothing display space is on design of clothing display space, layout, platform decoration style, platform models, performing colors, light arrangement, platform background, etc.

  19. A Modified SPH Method for Dynamic Failure Simulation of Heterogeneous Material

    Directory of Open Access Journals (Sweden)

    G. W. Ma

    2014-01-01

    Full Text Available A modified smoothed particle hydrodynamics (SPH method is applied to simulate the failure process of heterogeneous materials. An elastoplastic damage model based on an extension form of the unified twin shear strength (UTSS criterion is adopted. Polycrystalline modeling is introduced to generate the artificial microstructure of specimen for the dynamic simulation of Brazilian splitting test and uniaxial compression test. The strain rate effect on the predicted dynamic tensile and compressive strength is discussed. The final failure patterns and the dynamic strength increments demonstrate good agreements with experimental results. It is illustrated that the polycrystalline modeling approach combined with the SPH method is promising to simulate more complex failure process of heterogeneous materials.

  20. On interrelation of crack resistance characteristics of metal materials under static and dynamic loading conditions

    International Nuclear Information System (INIS)

    Abramyan, K.G.; Goloveshkin, Yu.V.; Tuzlukova, N.I.

    1984-01-01

    Home and foreign data on crack resistance characteristics of metal structural materials are generalized and analyzed. Dependence between various parameters of material strength and toughness on the one hand and racck resistance on the other hand is established on the basis of the energy concept of the failure mechanics. Effect of the strain rate on σsub(0.2) and Ksub(Ic) values is evaluated. Quanlitative and quantitative relations obtained permit conducting a complex estimation of materials behaviour during static and dynamic loading operations

  1. Comparative analyses on dynamic performances of photovoltaic–thermal solar collectors integrated with phase change materials

    International Nuclear Information System (INIS)

    Su, Di; Jia, Yuting; Alva, Guruprasad; Liu, Lingkun; Fang, Guiyin

    2017-01-01

    Highlights: • The dynamic model of photovoltaic–thermal collector with phase change material was developed. • The performances of photovoltaic–thermal collector are performed comparative analyses. • The performances of photovoltaic–thermal collector with phase change material were evaluated. • Upper phase change material mode can improve performances of photovoltaic–thermal collector. - Abstract: The operating conditions (especially temperature) of photovoltaic–thermal solar collectors have significant influence on dynamic performance of the hybrid photovoltaic–thermal solar collectors. Only a small percentage of incoming solar radiation can be converted into electricity, and the rest is converted into heat. This heat leads to a decrease in efficiency of the photovoltaic module. In order to improve the performance of the hybrid photovoltaic–thermal solar collector, we performed comparative analyses on a hybrid photovoltaic–thermal solar collector integrated with phase change material. Electrical and thermal parameters like solar cell temperature, outlet temperature of air, electrical power, thermal power, electrical efficiency, thermal efficiency and overall efficiency are simulated and analyzed to evaluate the dynamic performance of the hybrid photovoltaic–thermal collector. It is found that the position of phase change material layer in the photovoltaic–thermal collector has a significant effect on the performance of the photovoltaic–thermal collector. The results indicate that upper phase change material mode in the photovoltaic–thermal collector can significantly improve the thermal and electrical performance of photovoltaic–thermal collector. It is found that overall efficiency of photovoltaic–thermal collector in ‘upper phase change material’ mode is 10.7% higher than that in ‘no phase change material’ mode. Further, for a photovoltaic–thermal collector with upper phase change material, it is verified that 3 cm

  2. Dynamic fracture initiation in brittle materials under combined mode I/II loading

    International Nuclear Information System (INIS)

    Nakano, M.; Kishida, K.; Yamauchi, Y.; Sogabe, Y.

    1994-01-01

    A new test method has been developed to measure the resistance of dynamic fracture initiation in brittle materials under combined mode I/II loadings. The Brazilian disks with center-cracks have been fractured under oblique impact loadings in diametral-compression. The dynamic stress intensity factors of mode I and II are evaluated from the superposition integrals of the step response functions for the cracked disk. The experimental results are presented to elucidate the influence of loading rate on the combined mode fracture toughness for ceramics and glasses. (orig.)

  3. Building stock dynamics and its impacts on materials and energy demand in China

    International Nuclear Information System (INIS)

    Hong, Lixuan; Zhou, Nan; Feng, Wei; Khanna, Nina; Fridley, David; Zhao, Yongqiang; Sandholt, Kaare

    2016-01-01

    China hosts a large amount of building stocks, which is nearly 50 billion square meters. Moreover, annual new construction is growing fast, representing half of the world's total. The trend is expected to continue through the year 2050. Impressive demand for new residential and commercial construction, relative shorter average building lifetime, and higher material intensities have driven massive domestic production of energy intensive building materials such as cement and steel. This paper developed a bottom-up building stock turnover model to project the growths, retrofits and retirements of China's residential and commercial building floor space from 2010 to 2050. It also applied typical material intensities and energy intensities to estimate building materials demand and energy consumed to produce these building materials. By conducting scenario analyses of building lifetime, it identified significant potentials of building materials and energy demand conservation. This study underscored the importance of addressing building material efficiency, improving building lifetime and quality, and promoting compact urban development to reduce energy and environment consequences in China. - Highlights: •Growths of China's building floorspace were projected from 2010 to 2050. •A building stock turnover model was built to reflect annual building stock dynamics. •Building related materials and energy demand were projected.

  4. Non-adiabatic Excited State Molecule Dynamics Modeling of Photochemistry and Photophysics of Materials

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Tammie Renee [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tretiak, Sergei [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-01-06

    Understanding and controlling excited state dynamics lies at the heart of all our efforts to design photoactive materials with desired functionality. This tailor-design approach has become the standard for many technological applications (e.g., solar energy harvesting) including the design of organic conjugated electronic materials with applications in photovoltaic and light-emitting devices. Over the years, our team has developed efficient LANL-based codes to model the relevant photophysical processes following photoexcitation (spatial energy transfer, excitation localization/delocalization, and/or charge separation). The developed approach allows the non-radiative relaxation to be followed on up to ~10 ps timescales for large realistic molecules (hundreds of atoms in size) in the realistic solvent dielectric environment. The Collective Electronic Oscillator (CEO) code is used to compute electronic excited states, and the Non-adiabatic Excited State Molecular Dynamics (NA-ESMD) code is used to follow the non-adiabatic dynamics on multiple coupled Born-Oppenheimer potential energy surfaces. Our preliminary NA-ESMD simulations have revealed key photoinduced mechanisms controlling competing interactions and relaxation pathways in complex materials, including organic conjugated polymer materials, and have provided a detailed understanding of photochemical products and intermediates and the internal conversion process during the initiation of energetic materials. This project will be using LANL-based CEO and NA-ESMD codes to model nonradiative relaxation in organic and energetic materials. The NA-ESMD and CEO codes belong to a class of electronic structure/quantum chemistry codes that require large memory, “long-queue-few-core” distribution of resources in order to make useful progress. The NA-ESMD simulations are trivially parallelizable requiring ~300 processors for up to one week runtime to reach a meaningful restart point.

  5. Advances in computational dynamics of particles, materials and structures a unified approach

    CERN Document Server

    Har, Jason

    2012-01-01

    Computational methods for the modeling and simulation of the dynamic response and behavior of particles, materials and structural systems have had a profound influence on science, engineering and technology. Complex science and engineering applications dealing with complicated structural geometries and materials that would be very difficult to treat using analytical methods have been successfully simulated using computational tools. With the incorporation of quantum, molecular and biological mechanics into new models, these methods are poised to play an even bigger role in the future. Ad

  6. LDRD final report : mesoscale modeling of dynamic loading of heterogeneous materials

    Energy Technology Data Exchange (ETDEWEB)

    Robbins, Joshua [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Dingreville, Remi Philippe Michel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Voth, Thomas Eugene [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Furnish, Michael David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2013-12-01

    Material response to dynamic loading is often dominated by microstructure (grain structure, porosity, inclusions, defects). An example critically important to Sandia's mission is dynamic strength of polycrystalline metals where heterogeneities lead to localization of deformation and loss of shear strength. Microstructural effects are of broad importance to the scientific community and several institutions within DoD and DOE; however, current models rely on inaccurate assumptions about mechanisms at the sub-continuum or mesoscale. Consequently, there is a critical need for accurate and robust methods for modeling heterogeneous material response at this lower length scale. This report summarizes work performed as part of an LDRD effort (FY11 to FY13; project number 151364) to meet these needs.

  7. Self-consistent technique for estimating the dynamic yield strength of a shock-loaded material

    International Nuclear Information System (INIS)

    Asay, J.R.; Lipkin, J.

    1978-01-01

    A technique is described for estimating the dynamic yield stress in a shocked material. This method employs reloading and unloading data from a shocked state along with a general assumption of yield and hardening behavior to estimate the yield stress in the precompressed state. No other data are necessary for this evaluation, and, therefore, the method has general applicability at high shock pressures and in materials undergoing phase transitions. In some special cases, it is also possible to estimate the complete state of stress in a shocked state. Using this method, the dynamic yield strength of aluminum at 2.06 GPa has been estimated to be 0.26 GPa. This value agrees reasonably well with previous estimates

  8. Dynamics of the line-start reluctance motor with rotor made of SMC material

    Directory of Open Access Journals (Sweden)

    Smółka Krzysztof

    2017-12-01

    Full Text Available Design and control of electric motors in such a way as to ensure the expected motor dynamics, are the problems studied for many years. Many researchers tried to solve this problem, for example by the design optimization or by the use of special control algorithms in electronic systems. In the case of low-power and fractional power motors, the manufacture cost of the final product is many times less than cost of electronic system powering them. The authors of this paper attempt to improve the dynamic of 120 W line-start synchronous reluctance motor, energized by 50 Hz mains (without any electronic systems. The authors seek a road enabling improvement of dynamics of the analyzed motor, by changing the shape and material of the rotor, in such a way to minimize the modification cost of the tools necessary for the motor production. After the initial selection, the analysis of four rotors having different tooth shapes, was conducted.

  9. Torsional Shear Device for Testing the Dynamic Properties of Recycled Material

    Science.gov (United States)

    Gabryś, Katarzyna; Sas, Wojciech; Soból, Emil; Głuchowski, Andrzej

    2016-12-01

    From the viewpoint of environmental preservation and effective utilization of resources, it is beneficial and necessary to reuse wastes, for example, concrete, as the recycled aggregates for new materials. In this work, the dynamic behavior of such aggregates under low frequency torsional loading is studied. Results show that the properties of such artificial soils match with those reported in the literature for specific natural soils.

  10. Torsional Shear Device for Testing the Dynamic Properties of Recycled Material

    Directory of Open Access Journals (Sweden)

    Gabryś Katarzyna

    2016-12-01

    Full Text Available From the viewpoint of environmental preservation and effective utilization of resources, it is beneficial and necessary to reuse wastes, for example, concrete, as the recycled aggregates for new materials. In this work, the dynamic behavior of such aggregates under low frequency torsional loading is studied. Results show that the properties of such artificial soils match with those reported in the literature for specific natural soils.

  11. Paradoxical differences in N-dynamics between Luxembourg soils: litter quality or parent material?

    OpenAIRE

    Kooijman, A.M.; Smit, A.

    2009-01-01

    To explore whether litter quality could alter differences in N-dynamics between soil types, we compared spruce and beech growing on soils with parent material sandstone and limestone, and beech and hornbeam on acid marl and limestone. We measured pH, organic matter content, C:N ratio, soil respiration and net N-mineralization of the organic layer and the mineral topsoil in a laboratory incubation experiment and estimated gross N-mineralization and immobilization with a simulation model. Speci...

  12. Determination of the coefficient of dynamic friction between coatings of alumina and metallic materials

    Science.gov (United States)

    Santos, A.; Córdoba, E.; Ramírez, Z.; Sierra, C.; Ortega, Y.

    2017-12-01

    This project aims to determine the coefficient of dynamic friction between micrometric size coatings of alumina and metallic materials (Steel and aluminium); the methodology used to achieve the proposed objective consisted of 4 phases, in the first one was developed a procedure that allowed, from a Pin on Disk machine built based on the specifications given by the ASTM G99-05 standard (Standard test method for wear tests with a Pin on Disk machine), to determine the coefficient of dynamic friction between two materials in contact; subsequently the methodology was verified through tests between steel-steel and steel-aluminium, due to these values are widely reported in the literature; as a third step, deposits of alumina particles of micrometric size were made on a steel substrate through thermal spraying by flame; finally, the tests were carried out between pins of steel of aluminium and alumina coating to determine the coefficients of dynamic friction between these two surfaces. The results of the project allowed to verify that the developed methodology is valid to obtain coefficients of dynamic friction between surfaces in contact since the percentages of error were of 3.5% and 2.1% for steel-steel and aluminium-steel, respectively; additionally, it was found that the coefficient of friction between steel-alumina coatings is 0.36 and aluminium-alumina coating is 0.25.

  13. Young's moduli of carbon materials investigated by various classical molecular dynamics schemes

    Science.gov (United States)

    Gayk, Florian; Ehrens, Julian; Heitmann, Tjark; Vorndamme, Patrick; Mrugalla, Andreas; Schnack, Jürgen

    2018-05-01

    For many applications classical carbon potentials together with classical molecular dynamics are employed to calculate structures and physical properties of such carbon-based materials where quantum mechanical methods fail either due to the excessive size, irregular structure or long-time dynamics. Although such potentials, as for instance implemented in LAMMPS, yield reasonably accurate bond lengths and angles for several carbon materials such as graphene, it is not clear how accurate they are in terms of mechanical properties such as for instance Young's moduli. We performed large-scale classical molecular dynamics investigations of three carbon-based materials using the various potentials implemented in LAMMPS as well as the EDIP potential of Marks. We show how the Young's moduli vary with classical potentials and compare to experimental results. Since classical descriptions of carbon are bound to be approximations it is not astonishing that different realizations yield differing results. One should therefore carefully check for which observables a certain potential is suited. Our aim is to contribute to such a clarification.

  14. Dynamic and impact contact mechanics of geologic materials: Grain-scale experiments and modeling

    International Nuclear Information System (INIS)

    Cole, David M.; Hopkins, Mark A.; Ketcham, Stephen A.

    2013-01-01

    High fidelity treatments of the generation and propagation of seismic waves in naturally occurring granular materials is becoming more practical given recent advancements in our ability to model complex particle shapes and their mechanical interaction. Of particular interest are the grain-scale processes that are activated by impact events and the characteristics of force transmission through grain contacts. To address this issue, we have developed a physics based approach that involves laboratory experiments to quantify the dynamic contact and impact behavior of granular materials and incorporation of the observed behavior indiscrete element models. The dynamic experiments do not involve particle damage and emphasis is placed on measured values of contact stiffness and frictional loss. The normal stiffness observed in dynamic contact experiments at low frequencies (e.g., 10 Hz) are shown to be in good agreement with quasistatic experiments on quartz sand. The results of impact experiments – which involve moderate to extensive levels of particle damage – are presented for several types of naturally occurring granular materials (several quartz sands, magnesite and calcium carbonate ooids). Implementation of the experimental findings in discrete element models is discussed and the results of impact simulations involving up to 5 × 105 grains are presented.

  15. Dynamic and impact contact mechanics of geologic materials: Grain-scale experiments and modeling

    Energy Technology Data Exchange (ETDEWEB)

    Cole, David M.; Hopkins, Mark A.; Ketcham, Stephen A. [Engineer Research and Development Center - Cold Regions Research and Engineering Laboratory, 72 Lyme Rd., Hanover, NH 03755 (United States)

    2013-06-18

    High fidelity treatments of the generation and propagation of seismic waves in naturally occurring granular materials is becoming more practical given recent advancements in our ability to model complex particle shapes and their mechanical interaction. Of particular interest are the grain-scale processes that are activated by impact events and the characteristics of force transmission through grain contacts. To address this issue, we have developed a physics based approach that involves laboratory experiments to quantify the dynamic contact and impact behavior of granular materials and incorporation of the observed behavior indiscrete element models. The dynamic experiments do not involve particle damage and emphasis is placed on measured values of contact stiffness and frictional loss. The normal stiffness observed in dynamic contact experiments at low frequencies (e.g., 10 Hz) are shown to be in good agreement with quasistatic experiments on quartz sand. The results of impact experiments - which involve moderate to extensive levels of particle damage - are presented for several types of naturally occurring granular materials (several quartz sands, magnesite and calcium carbonate ooids). Implementation of the experimental findings in discrete element models is discussed and the results of impact simulations involving up to 5 Multiplication-Sign 105 grains are presented.

  16. Dynamic testing of horseshoe designs at impact on synthetic and dirt Thoroughbred racetrack materials.

    Science.gov (United States)

    Mahaffey, C A; Peterson, M L; Thomason, J J; McIlwraith, C W

    2016-01-01

    Different horseshoe designs have been developed in an attempt to optimise footing for equine athletes. Horseshoe performance is assumed to be dependent on the surface and gait, but there are limited data on horseshoe performance on different surfaces, independent of gait variation. To quantify the dynamic loading for 3 aluminium racing shoe designs on Thoroughbred racetrack surface materials, using a biomechanical surface tester. A flat racing plate, a serrated V-Grip and a shoe with a 6 mm toe grab and 10 mm heel calks were tested on synthetic and dirt surfaces under typical operating conditions of temperature and moisture content for the respective material samples. Samples were tested under laboratory conditions, replicating a track surface by compacting material into a latex-lined mould surrounded by silica sand for representative boundary conditions. Peak loading and loading rates were measured vertically and horizontally (craniocaudal), simulating aspects of primary and secondary impacts of the hoof in a galloping horse. Maximum vertical and shear loads and loading rates were not significantly different between shoe types, with the exception of a reduced craniocaudal loading rate for the V-Grip shoe on the synthetic surface. All other statistical significance was related to the surface material. These 3 different Thoroughbred racing shoes do not have a significant impact on loading and loading rate, with the exception of the V-Grip shoe on a synthetic surface. Although the V-Grip may reduce craniocaudal peak load rates in a synthetic material with relatively high wax and/or low oil content, the reduction in load rate is less than the difference found between materials. This study indicates that shoeing has little effect, and that a track's surface material and its preparation have a significant effect on the dynamic loading during the impact phase of the stance. © 2015 EVJ Ltd.

  17. Debris flow analysis with a one dimensional dynamic run-out model that incorporates entrained material

    Science.gov (United States)

    Luna, Byron Quan; Remaître, Alexandre; van Asch, Theo; Malet, Jean-Philippe; van Westen, Cees

    2010-05-01

    Estimating the magnitude and the intensity of rapid landslides like debris flows is fundamental to evaluate quantitatively the hazard in a specific location. Intensity varies through the travelled course of the flow and can be described by physical features such as deposited volume, velocities, height of the flow, impact forces and pressures. Dynamic run-out models are able to characterize the distribution of the material, its intensity and define the zone where the elements will experience an impact. These models can provide valuable inputs for vulnerability and risk calculations. However, most dynamic run-out models assume a constant volume during the motion of the flow, ignoring the important role of material entrained along its path. Consequently, they neglect that the increase of volume enhances the mobility of the flow and can significantly influence the size of the potential impact area. An appropriate erosion mechanism needs to be established in the analyses of debris flows that will improve the results of dynamic modeling and consequently the quantitative evaluation of risk. The objective is to present and test a simple 1D debris flow model with a material entrainment concept based on limit equilibrium considerations and the generation of excess pore water pressure through undrained loading of the in situ bed material. The debris flow propagation model is based on a one dimensional finite difference solution of a depth-averaged form of the Navier-Stokes equations of fluid motions. The flow is treated as a laminar one phase material, which behavior is controlled by a visco-plastic Coulomb-Bingham rheology. The model parameters are evaluated and the model performance is tested on a debris flow event that occurred in 2003 in the Faucon torrent (Southern French Alps).

  18. Multi-Objective Emergency Material Vehicle Dispatching and Routing under Dynamic Constraints in an Earthquake Disaster Environment

    Directory of Open Access Journals (Sweden)

    Jincheng Jiang

    2017-05-01

    Full Text Available Emergency material vehicle dispatching and routing (EMVDR is an important task in emergency relief after large-scale earthquake disasters. However, EMVDR is subject to dynamic disaster environment, with uncertainty surrounding elements such as the transportation network and relief materials. Accurate and dynamic emergency material dispatching and routing is difficult. This paper proposes an effective and efficient multi-objective multi-dynamic-constraint emergency material vehicle dispatching and routing model. Considering travel time, road capacity, and material supply and demand, the proposed EMVDR model is to deliver emergency materials from multiple emergency material depositories to multiple disaster points while satisfying the objectives of maximizing transport efficiency and minimizing the difference of material urgency degrees among multiple disaster points at any one time. Furthermore, a continuous-time dynamic network flow method is developed to solve this complicated model. The collected data from Ludian earthquake were used to conduct our experiments in the post-quake and the results demonstrate that: (1 the EMVDR model adapts to the dynamic disaster environment very well; (2 considering the difference of material urgency degree, the material loss ratio is −10.7%, but the variance of urgency degree decreases from 2.39 to 0.37; (3 the EMVDR model shows good performance in time and space, which allows for decisions to be made nearly in real time. This paper can provide spatial decision-making support for emergency material relief in large-scale earthquake disasters.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-09-01

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

  20. Assessment of a dynamic reference material for calibration of full-field measurement systems

    Science.gov (United States)

    Hack, Erwin; Feligiotti, Mara; Davighi, Andrea; Whelan, Maurice; Wang, Weizhuo V.; Patterson, Eann A.

    2012-10-01

    For holography and speckle interferometry the calibration of the sensitivity is a must, because illumination and observation directions vary across the field of view. A numerical estimate or a static calibration using rigid body motions is standard, and reference materials exist for static strain calibration. Recently, reference materials for the dynamic calibration of optical instruments of displacement and strain measurement were designed and prototypes were manufactured in the European FP7 project ADVISE. We review the properties of the reference material and the concept of traceability for the field of displacement values by using a calibrated single point transducer. The mode shape is assessed using out-of-plane DSPI, Finite Element Analysis as well as analytic solutions of the plate vibration. We present measurements using stroboscopic DSPI on the reference material under acoustic excitation and compare the measured mode shapes to the ones predicted by FE analysis. We apply different comparison methodologies based on point-by-point deviations and on decomposition of the mode shapes into a set of orthogonal basis functions. The latter method is well suited to assess stability and reproducibility of a mode shape. Finally, the deviations are used to estimate the reference material uncertainty which is an essential parameter for determining the calibration uncertainty. Uncertainty contributions of the DSPI set-up are taken into account. To conclude, the application area and limitations of the reference material are discussed.

  1. Experimental studies of dynamic impact response with scale models of lead shielded radioactive material shipping containers

    International Nuclear Information System (INIS)

    Robinson, R.A.; Hadden, J.A.; Basham, S.J.

    1978-01-01

    Preliminary experimental studies of dynamic impact response of scale models of lead-shielded radioactive material shipping containers are presented. The objective of these studies is to provide DOE/ECT with a data base to allow the prediction of a rational margin of confidence in overviewing and assessing the adequacy of the safety and environmental control provided by these shipping containers. Replica scale modeling techniques were employed to predict full scale response with 1/8, 1/4, and 1/2 scale models of shipping containers that are used in the shipment of spent nuclear fuel and high level wastes. Free fall impact experiments are described for scale models of plain cylindrical stainless steel shells, stainless steel shells filled with lead, and replica scale models of radioactive material shipping containers. Dynamic induced strain and acceleration measurements were obtained at several critical locations on the models. The models were dropped from various heights, attitudes to the impact surface, with and without impact limiters and at uniform temperatures between -40 and 175 0 C. In addition, thermal expansion and thermal gradient induced strains were measured at -40 and 175 0 C. The frequency content of the strain signals and the effect of different drop pad compositions and stiffness were examined. Appropriate scale modeling laws were developed and scaling techniques were substantiated for predicting full scale response by comparison of dynamic strain data for 1/8, 1/4, and 1/2 scale models with stainless steel shells and lead shielding

  2. Laser-solid interaction and dynamics of the laser-ablated materials

    International Nuclear Information System (INIS)

    Chen, K.R.; Leboeuf, J.N.; Geohegan, D.B.; Wood, R.F.; Donato, J.M.; Liu, C.L.; Puretzky, A.A.

    1995-01-01

    Rapid transformations through the liquid and vapor phases induced by laser-solid interactions are described by the authors' thermal model with the Clausius-Clapeyron equation to determine the vaporization temperature under different surface pressure condition. Hydrodynamic behavior of the vapor during and after ablation is described by gas dynamic equations. These two models are coupled. Modeling results show that lower background pressure results lower laser energy density threshold for vaporization. The ablation rate and the amount of materials removed are proportional to the laser energy density above its threshold. The authors also demonstrate a dynamic source effect that accelerates the unsteady expansion of laser-ablated material in the direction perpendicular to the solid. A dynamic partial ionization effect is studied as well. A self-similar theory shows that the maximum expansion velocity is proportional to c s α, where 1 - α is the slope of the velocity profile. Numerical hydrodynamic modeling is in good agreement with the theory. With these effects, α is reduced. Therefore, the expansion front velocity is significantly higher than that from conventional models. The results are consistent with experiments. They further study how the plume propagates in high background gas condition. Under appropriate conditions, the plume is slowed down, separates with the background, is backward moving, and hits the solid surface. Then, it splits into two parts when it rebounds from the surface. The results from the modeling will be compared with experimental observations where possible

  3. Mechanical behavior of ultrafine-grained materials under combined static and dynamic loadings

    Directory of Open Access Journals (Sweden)

    Guo Y.Z.

    2015-01-01

    Full Text Available Ultrafine-grained (UFG materials have extensive prospects for engineering application due to their excellent mechanical properties. However, the grain size decrease reduces their strain hardening ability and makes UFG materials more susceptible to deformation instability such as shear localization. In most cases, critical shear strain is taken as the criterion for formation of shear localization under impact loading or adiabatic shear band (ASB. Recently, some researchers found that the formation of ASB was determined only by the dynamic loading process and had nothing to do with its static loading history. They proposed for coarse-grained metals a dynamic stored energy-based criterion for ASB and verified it by some experiments. In this study, we will focus on the shear localization behavior of UFG metals such as UFG titanium and magnesium alloy AZ31. Quasi-static loading and dynamic loading will be applied on the same specimen alternately. The shear localization behavior will be analyzed and the criterion of its formation will be evaluated.

  4. Elastic Characterization of Transversely Isotropic Soft Materials by Dynamic Shear and Asymmetric Indentation

    Science.gov (United States)

    Namani, R.; Feng, Y.; Okamoto, R. J.; Jesuraj, N.; Sakiyama-Elbert, S. E.; Genin, G. M.; Bayly, P. V.

    2012-01-01

    The mechanical characterization of soft anisotropic materials is a fundamental challenge because of difficulties in applying mechanical loads to soft matter and the need to combine information from multiple tests. A method to characterize the linear elastic properties of transversely isotropic soft materials is proposed, based on the combination of dynamic shear testing (DST) and asymmetric indentation. The procedure was demonstrated by characterizing a nearly incompressible transversely isotropic soft material. A soft gel with controlled anisotropy was obtained by polymerizing a mixture of fibrinogen and thrombin solutions in a high field magnet (B = 11.7 T); fibrils in the resulting gel were predominantly aligned parallel to the magnetic field. Aligned fibrin gels were subject to dynamic (20–40 Hz) shear deformation in two orthogonal directions. The shear storage modulus was 1.08 ± 0. 42 kPa (mean ± std. dev.) for shear in a plane parallel to the dominant fiber direction, and 0.58 ± 0.21 kPa for shear in the plane of isotropy. Gels were indented by a rectangular tip of a large aspect ratio, aligned either parallel or perpendicular to the normal to the plane of transverse isotropy. Aligned fibrin gels appeared stiffer when indented with the long axis of a rectangular tip perpendicular to the dominant fiber direction. Three-dimensional numerical simulations of asymmetric indentation were used to determine the relationship between direction-dependent differences in indentation stiffness and material parameters. This approach enables the estimation of a complete set of parameters for an incompressible, transversely isotropic, linear elastic material. PMID:22757501

  5. Theoretical study of laser feedback interferometry for dynamical material's behaviour studies

    International Nuclear Information System (INIS)

    Le-Barbier, Laura

    2017-01-01

    The purpose of this thesis is to study the feasibility of optical feedback interferometry (OFI) for measuring velocities for dynamical material's behaviour studies. Dynamical material's behaviour studies permit to analyse the shocked material when subjects to shocks (laser shocks, isentropic compression, projectiles, etc.). In these conditions, we seek to measure velocities up to 10 km/s. The OFI technique is regularly used as an embedded system to measure slow velocities in various fields. However, very few studies have been performed for determining velocities measurement limits for this system. As a matter of fact, the optical feedback induces nonlinear effects into the laser's cavity: it disrupts the laser's emitted optical power. Depending on the optical feedback strength, the laser can show chaotic behaviour, then it is no longer possible to get the information for the target's velocity or displacement regarding the signal. In this study, we have been developing mathematical models and performing a wide range of numerical simulations to study the performances and the limits of the OFI technique. We have been also studying the influence of the targets reflectivity, the length and the modulation frequency of the external cavity. (author) [fr

  6. Electric Resistance Tests on Compacted Clay Material under Dynamic Load Coupled with Dry-Wet Cycling

    Directory of Open Access Journals (Sweden)

    Zheng Lu

    2018-01-01

    Full Text Available The study of compacted clay material under dynamic load coupled with dry-wet cycling is one of the most important areas in the field of transportation. In this paper, experiments in terms of compacted clay under dynamic load coupled with dry-wet cycling are performed, and synchronous resistivity tests are also conducted. According to the test results, the influences of cumulative plastic strain, dry-wet cycles, and amplitudes on the soil resistivity are analyzed. Then a new damage factor based on resistivity is proposed to evaluate the long-term performance of compacted clay material. The result of research shows that the evolution of the soil resistivity can be divided into two stages, which has a contrary tendency with that of cumulative plastic strain. The dry-wet cycles and amplitudes have a significant effect on the damage of the compacted soil, which indicates that the dry-wet cycling of compacted soil materials should not be ignored in road engineering, especially in rainy and humid areas.

  7. Dynamics expansion of laser produced plasma with different materials in magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Rabia Qindeel; Noriah Bte Bidin; Yaacob Mat daud [Laser Technology Laboratory, Physics Department, Universiti Teknologi Malaysia, Skudai 81310, Johor (Malaysia)], E-mail: plasmaqindeel@yahoo.com

    2008-12-01

    The dynamics expansion of the plasma generated by laser ablation of different materials has been investigated. The dynamics and confinement of laser generated plasma plumes are expanding across variable magnetic fields. A Q-switched neodymium-doped yttrium aluminum garnet laser with 1064 nm, 8 ns pulse width and 0.125 J laser energy was used to generate plasma that was allowed to expand across variable magnetic within 0.1 - 0.8 T. The expansions of laser-produced plasma of different materials are characterized by using constant laser power. CCD video camera was used to visualize and record the activities in the focal region. The plasma plume length, width and area were measured by using Matrox Inpector 2.1 and video Test 0.5 software. Spectrums of plasma beam from different materials are studied via spectrometer. The results show that the plasma generated by aluminum target is the largest than Brass and copper. The optical radiation from laser generated plasma beam spectrums are obtained in the range of UV to visible light.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-04-01

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

  9. Thickness determination in textile material design: dynamic modeling and numerical algorithms

    International Nuclear Information System (INIS)

    Xu, Dinghua; Ge, Meibao

    2012-01-01

    Textile material design is of paramount importance in the study of functional clothing design. It is therefore important to determine the dynamic heat and moisture transfer characteristics in the human body–clothing–environment system, which directly determine the heat–moisture comfort level of the human body. Based on a model of dynamic heat and moisture transfer with condensation in porous fabric at low temperature, this paper presents a new inverse problem of textile thickness determination (IPTTD). Adopting the idea of the least-squares method, we formulate the IPTTD into a function minimization problem. By means of the finite-difference method, quasi-solution method and direct search method for one-dimensional minimization problems, we construct iterative algorithms of the approximated solution for the IPTTD. Numerical simulation results validate the formulation of the IPTTD and demonstrate the effectiveness of the proposed numerical algorithms. (paper)

  10. The dynamics of a non-equilibrium bubble near bio-materials

    International Nuclear Information System (INIS)

    Ohl, S W; Klaseboer, E; Khoo, B C

    2009-01-01

    In many medical treatments oscillating (non-equilibrium) bubbles appear. They can be the result of high-intensity-focused ultrasound, laser treatments or shock wave lithotripsy for example. The physics of such oscillating bubbles is often not very well understood. This is especially so if the bubbles are oscillating near (soft) bio-materials. It is well known that bubbles oscillating near (hard) materials have a tendency to form a high speed jet directed towards the material during the collapse phase of the bubble. It is equally well studied that bubbles near a free interface (air) tend to collapse with a jet directed away from this interface. If the interface is neither 'free' nor 'hard', such as often occurs in bio-materials, the resulting flow physics can be very complex. Yet, in many bio-applications, it is crucial to know in which direction the jet will go (if there is a jet at all). Some applications require a jet towards the tissue, for example to destroy it. For other applications, damage due to impacting jets is to be prevented at all cost. This paper tries to address some of the physics involved in these treatments by using a numerical method, the boundary element method (BEM), to study the dynamics of such bubbles near several bio-materials. In the present work, the behaviour of a bubble placed in a water-like medium near various bio-materials (modelled as elastic fluids) is investigated. It is found that its behaviour depends on the material properties (Young's modulus, Poisson ratio and density) of the bio-material. For soft bio-materials (fat, skin, brain and muscle), the bubble tends to split into smaller bubbles. In certain cases, the resulting bubbles develop opposing jets. For hard bio-materials (cornea, cartilage and bone), the bubble collapses towards the interface with high speed jets (between 100 and about 250 m s -1 ). A summary graph is provided identifying the combined effects of the dimensionless elasticity (κ) and density ratio (α) of

  11. Dynamic behavior of cellular materials and cellular structures: Experiments and modeling

    Science.gov (United States)

    Gao, Ziyang

    Cellular solids, including cellular materials and cellular structures (CMS), have attracted people's great interests because of their low densities and novel physical, mechanical, thermal, electrical and acoustic properties. They offer potential for lightweight structures, energy absorption, thermal management, etc. Therefore, the studies of cellular solids have become one of the hottest research fields nowadays. From energy absorption point of view, any plastically deformed structures can be divided into two types (called type I and type II), and the basic cells of the CMS may take the configurations of these two types of structures. Accordingly, separated discussions are presented in this thesis. First, a modified 1-D model is proposed and numerically solved for a typical type II structure. Good agreement is achieved with the previous experimental data, hence is used to simulate the dynamic behavior of a type II chain. Resulted from different load speeds, interesting collapse modes are observed, and the parameters which govern the cell's post-collapse behavior are identified through a comprehensive non-dimensional analysis on general cellular chains. Secondly, the MHS specimens are chosen as an example of type I foam materials because of their good uniformity of the cell geometry. An extensive experimental study was carried out, where more attention was paid to their responses to dynamic loadings. Great enhancement of the stress-strain curve was observed in dynamic cases, and the energy absorption capacity is found to be several times higher than that of the commercial metal foams. Based on the experimental study, finite elemental simulations and theoretical modeling are also conducted, achieving good agreements and demonstrating the validities of those models. It is believed that the experimental, numerical and analytical results obtained in the present study will certainly deepen the understanding of the unsolved fundamental issues on the mechanical behavior of

  12. Dynamic response of materials on subnanosecond time scales, and beryllium properties for inertial confinement fusion

    International Nuclear Information System (INIS)

    Swift, Damian C.; Tierney, Thomas E.; Luo Shengnian; Paisley, Dennis L.; Kyrala, George A.; Hauer, Allan; Greenfield, Scott R.; Koskelo, Aaron C.; McClellan, Kenneth J.; Lorenzana, Hector E.; Kalantar, Daniel; Remington, Bruce A.; Peralta, Pedro; Loomis, Eric

    2005-01-01

    During the past few years, substantial progress has been made in developing experimental techniques capable of investigating the response of materials to dynamic loading on nanosecond time scales and shorter, with multiple diagnostics probing different aspects of the behavior. These relatively short time scales are scientifically interesting because plastic flow and phase changes in common materials with simple crystal structures--such as iron--may be suppressed, allowing unusual states to be induced and the dynamics of plasticity and polymorphism to be explored. Loading by laser-induced ablation can be particularly convenient: this technique has been used to impart shocks and isentropic compression waves from ∼1 to 200 GPa in a range of elements and alloys, with diagnostics including line imaging surface velocimetry, surface displacement (framed area imaging), x-ray diffraction (single crystal and polycrystal), ellipsometry, and Raman spectroscopy. A major motivation has been the study of the properties of beryllium under conditions relevant to the fuel capsule in inertial confinement fusion: magnetically driven shock and isentropic compression shots at Z were used to investigate the equation of state and shock melting characteristics, complemented by laser ablation experiments to investigate plasticity and heterogeneous response from the polycrystalline microstructure. These results will help to constrain acceptable tolerances on manufacturing, and possible loading paths, for inertial fusion ignition experiments at the National Ignition Facility. Laser-based techniques are being developed further for future material dynamics experiments, where it should be possible to obtain high quality data on strength and phase changes up to at least 1 TPa

  13. Assessing the dynamic material criticality of infrastructure transitions: A case of low carbon electricity

    International Nuclear Information System (INIS)

    Roelich, Katy; Dawson, David A.; Purnell, Phil; Knoeri, Christof; Revell, Ruairi; Busch, Jonathan; Steinberger, Julia K.

    2014-01-01

    Highlights: • We present a method to analyse material criticality of infrastructure transitions. • Criticality is defined as the potential for, and exposure to, supply disruption. • Our method is dynamic reducing the probability of lock-in to at-risk technologies. • We show that supply disruption potential is reducing but exposure is increasing. - Abstract: Decarbonisation of existing infrastructure systems requires a dynamic roll-out of technology at an unprecedented scale. The potential disruption in supply of critical materials could endanger such a transition to low-carbon infrastructure and, by extension, compromise energy security more broadly because low carbon technologies are reliant on these materials in a way that fossil-fuelled energy infrastructure is not. Criticality is currently defined as the combination of the potential for supply disruption and the exposure of a system of interest to that disruption. We build on this definition and develop a dynamic approach to quantifying criticality, which monitors the change in criticality during the transition towards a low-carbon infrastructure goal. This allows us to assess the relative risk of different technology pathways to reach a particular goal and reduce the probability of being ‘locked in’ to currently attractive but potentially future-critical technologies. To demonstrate, we apply our method to criticality of the proposed UK electricity system transition, with a focus on neodymium. We anticipate that the supply disruption potential of neodymium will decrease by almost 30% by 2050; however, our results show the criticality of low carbon electricity production increases ninefold over this period, as a result of increasing exposure to neodymium-reliant technologies

  14. An Introduction to the Material Point Method using a Case Study from Gas Dynamics

    International Nuclear Information System (INIS)

    Tran, L. T.; Kim, J.; Berzins, M.

    2008-01-01

    The Material Point Method (MPM) developed by Sulsky and colleagues is currently being used to solve many challenging problems involving large deformations and/or fragementations with considerable success as part of the Uintah code created by the CSAFE project. In order to understand the properties of this method an analysis of the considerable computational properties of MPM is undertaken in the context of model problems from gas dynamics. One aspect of the MPM method in the form used here is shown to have first order accuracy. Computational experiments using particle redistribution are described and show that smooth results with first order accuracy may be obtained.

  15. Investigation of dynamic of unconsolidated materials using two-color digital holography

    Directory of Open Access Journals (Sweden)

    Boileau J.-P.

    2010-06-01

    Full Text Available The paper presents a two-color digital holographic interferometer. The set-up is devoted to the study of the fundamental dynamic of unconsolidated materials. Optical configuration and algorithms to recover the optical phase of two-color digitally encoded holograms are described. The method is based on a spatial-color-multiplexing scheme in which holographic reconstruction is performed using adapted wavelength zero-padding and reconstructing distance. Experimental results are presented in the case of granular media excited in the frequency range 400Hz-3000Hz and exhibits the 3D movement.

  16. Apparatus for dynamic measurement of gases released from materials heated under programmed temperature-time control

    International Nuclear Information System (INIS)

    Early, J.W.; Abernathey, R.M.

    1982-04-01

    This apparatus, a prototype of one being constructed for hotcell examination of irradiated nuclear materials, measures dynamic release rates and integrated volumes of individual gases from materials heated under controlled temperature-time programs. It consists of an inductively heated vacuum furnace connected to a quadrupole mass spectrometer. A computerized control system with data acquisition provides scanning rates down to 1s and on-line tabular and graphic displays. Heating rates are up to 1300 0 C/min to a maximum temperature of 2000 0 C. The measurement range is about 10 -6 to 10 -2 torr-liter/s for H 2 , CH 4 , H 2 O, N 2 , and CO and 10 -8 to 10 -2 torr-liter/s for He, Kr, and Xe. Applications are described for measurements of Kr and Xe in mixed oxide fuel, various gases in UO 2 pellets, and He in 238 PuO 2 power and heat sources

  17. Excited state and charge-carrier dynamics in perovskite solar cell materials

    Science.gov (United States)

    Ponseca, Carlito S., Jr.; Tian, Yuxi; Sundström, Villy; Scheblykin, Ivan G.

    2016-02-01

    Organo-metal halide perovskites (OMHPs) have attracted enormous interest in recent years as materials for application in optoelectronics and solar energy conversion. These hybrid semiconductors seem to have the potential to challenge traditional silicon technology. In this review we will give an account of the recent development in the understanding of the fundamental light-induced processes in OMHPs from charge-photo generation, migration of charge carries through the materials and finally their recombination. Our and other literature reports on time-resolved conductivity, transient absorption and photoluminescence properties are used to paint a picture of how we currently see the fundamental excited state and charge-carrier dynamics. We will also show that there is still no fully coherent picture of the processes in OMHPs and we will indicate the problems to be solved by future research.

  18. Excited state and charge-carrier dynamics in perovskite solar cell materials

    International Nuclear Information System (INIS)

    Ponseca, Carlito S Jr; Tian, Yuxi; Sundström, Villy; Scheblykin, Ivan G

    2016-01-01

    Organo-metal halide perovskites (OMHPs) have attracted enormous interest in recent years as materials for application in optoelectronics and solar energy conversion. These hybrid semiconductors seem to have the potential to challenge traditional silicon technology. In this review we will give an account of the recent development in the understanding of the fundamental light-induced processes in OMHPs from charge-photo generation, migration of charge carries through the materials and finally their recombination. Our and other literature reports on time-resolved conductivity, transient absorption and photoluminescence properties are used to paint a picture of how we currently see the fundamental excited state and charge-carrier dynamics. We will also show that there is still no fully coherent picture of the processes in OMHPs and we will indicate the problems to be solved by future research. (topical review)

  19. Validating Material Modelling of OFHC Copper Using Dynamic Tensile Extrusion (DTE) Test at Different Impact Velocity

    Science.gov (United States)

    Bonora, Nicola; Testa, Gabriel; Ruggiero, Andrew; Iannitti, Gianluca; Hörnqvist, Magnus; Mortazavi, Nooshin

    2015-06-01

    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 phenomenological and physically based models (Johnson-Cook, Zerilli-Armstrong and Rusinek-Klepaczko), are presented. Preliminary simulation of microstructure evolution was performed using crystal plasticity package CPFEM, providing, as input, the strain history obtained with FEM at selected locations along the extruded fragments. Results were compared with EBSD investigation.

  20. Automated nuclear material recovery and decontamination of large steel dynamic experiment containers

    International Nuclear Information System (INIS)

    Dennison, D.K.; Gallant, D.A.; Nelson, D.C.; Stovall, L.A.; Wedman, D.E.

    1999-01-01

    A key mission of the Los Alamos National Laboratory (LANL) is to reduce the global nuclear danger through stockpile stewardship efforts that ensure the safety and reliability of nuclear weapons. In support of this mission LANL performs dynamic experiments on special nuclear materials (SNM) within large steel containers. Once these experiments are complete, these containers must be processed to recover residual SNM and to decontaminate the containers to below low level waste (LLW) disposal limits which are much less restrictive for disposal purposes than transuranic (TRU) waste limits. The purpose of this paper is to describe automation efforts being developed by LANL for improving the efficiency, increasing worker safety, and reducing worker exposure during the material cleanout and recovery activities performed on these containers

  1. Effect of pulsed-column-inventory uncertainty on dynamic materials accounting

    International Nuclear Information System (INIS)

    Ostenak, C.A.

    1985-01-01

    Reprocessing plants worldwide use the Purex solvent-extraction process and pulsed-column contactors to separate and purify uranium and plutonium from spent nuclear fuels. The importance of contactor in-process inventory to dynamic materials accounting in reprocessing plants is illustrated using the Allied-General Nuclear Services Plutonium Purification Process (PPP) of the now decommissioned Barnwell Nuclear Fuels Plant. This study shows that (1) good estimates of column inventory are essential for detecting short-term losses of in-process materials, but that (2) input-output (transfer) measurement correlations limit the accounting sensitivity for longer accounting periods (greater than or equal to 1 wk for the PPP). 6 refs., 2 figs., 3 tabs

  2. Material Removal and Specific Energy in the Dynamic Scratching of Gamma Titanium Aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H.; Lin, H.-T.; Wereszczak, A.A.

    2006-11-30

    Mechanical responses of three gamma titanium aluminides (TiAls) (denoted as Alloy A, Alloy B and Alloy C) subjected to dynamic scratching were studied by using a single-grit pendulum (rotating) scratch tester. The maximum depth of groove was {approx} 0.07 mm, and the scratch velocity was {approx} 1.0 m/s. Normal and tangential forces were monitored. The material removal mechanisms were examined using a scanning electron microscope (SEM) and the scratches were measured by using a laser profilometer. The mechanical properties of the tested TiAls were characterized by the instantaneous specific energy, scratch resistance and scratch hardness as related to the groove depth. Extensive thermal softening was observed in the dynamic scratch test of the TiAls, which facilitated both the detachment of developing chips and pile-up of material on side ridges. Sizable fractures were observed in the transverse direction in the tested TiAls; these fractures tended to participate in the chip formation, depending on the microstructure of the TiAl and the size of the scratch groove. Specific energy and scratch hardness are depth-dependent to various degrees for the TiAls tested. The material removal might be subjected to different mechanisms, but the overall material response can be effectively characterized by the HEM (Hwang, Evans and Malkin) model and the PSR (proportional specimen resistance) model. The depth-independent specific energy and scratch hardness can be used to screen candidate materials for the applications that are scratch-dominated versus impact-dominated. Among the three tested TiAls, the TiAl with larger colony or grain size exhibits a stronger capability of energy dissipation during material removal (higher depth-independent specific energy), while the TiAl with smaller colony size shows a higher resistance to indentation (higher depth-independent scratch hardness). The observations and conclusions in this study can serve as a base line for the further

  3. Material Removal and Specific Energy in the Dynamic Scratching of Gamma Titanium Aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hong [ORNL; Lin, Hua-Tay [ORNL; Wereszczak, Andrew A [ORNL

    2006-11-01

    Mechanical responses of three gamma titanium aluminides (TiAls) (denoted as Alloy A, Alloy B and Alloy C) subjected to dynamic scratching were studied by using a single-grit pendulum (rotating) scratch tester. The maximum depth of groove was ~ 0.07 mm, and the scratch velocity used was ~ 1.0 m/s. Normal and tangential forces were monitored. The material removal mechanisms were examined using a scanning electron microscope (SEM) and the scratches were measured by using a laser profilometer. The mechanical properties of the tested TiAls were characterized by the instantaneous specific energy, scratch resistance and scratch hardness as related to the depth of groove. Extensive thermal softening was observed in the dynamic scratch of the tested TiAls, which facilitated both the detachments of developing chips and the pile-ups of materials on side ridges. Sizable fractures were observed in the transverse direction on the tested TiAls; these fractures tended to participate in the chip formation, depending on the microstructure of the TiAl and the size of the scratch groove. Specific energy and scratch hardness are depth-dependent to various degrees for the tested TiAls. The materiel removal might be subjected to different mechanisms, but the overall response of materials can be effectively characterized by the HEM (Hwang, Evans and Malkin) model and the PSR (proportional specimen resistance) model. The obtained depth-independent specific energy and scratch hardness can be used to screen the candidate materials for the specific purpose depending on whether the application is scratch-dominant or impact-dominant. Among the three tested TiAls, the TiAl with larger colony or grain size exhibits a stronger capability of energy dissipation in the material loss or material removal (higher depth-independent specific energy), while the TiAl with smaller colony size show a higher resistance against the indentation (higher depth-independent scratch hardness). The observations and

  4. Numerical investigations on flow dynamics of prismatic granular materials using the discrete element method

    Science.gov (United States)

    Hancock, W.; Weatherley, D.; Wruck, B.; Chitombo, G. P.

    2012-04-01

    The flow dynamics of granular materials is of broad interest in both the geosciences (e.g. landslides, fault zone evolution, and brecchia pipe formation) and many engineering disciplines (e.g chemical engineering, food sciences, pharmaceuticals and materials science). At the interface between natural and human-induced granular media flow, current underground mass-mining methods are trending towards the induced failure and subsequent gravitational flow of large volumes of broken rock, a method known as cave mining. Cave mining relies upon the undercutting of a large ore body, inducement of fragmentation of the rock and subsequent extraction of ore from below, via hopper-like outlets. Design of such mines currently relies upon a simplified kinematic theory of granular flow in hoppers, known as the ellipsoid theory of mass movement. This theory assumes that the zone of moving material grows as an ellipsoid above the outlet of the silo. The boundary of the movement zone is a shear band and internal to the movement zone, the granular material is assumed to have a uniformly high bulk porosity compared with surrounding stagnant regions. There is however, increasing anecdotal evidence and field measurements suggesting this theory fails to capture the full complexity of granular material flow within cave mines. Given the practical challenges obstructing direct measurement of movement both in laboratory experiments and in-situ, the Discrete Element Method (DEM [1]) is a popular alternative to investigate granular media flow. Small-scale DEM studies (c.f. [3] and references therein) have confirmed that movement within DEM silo flow models matches that predicted by ellipsoid theory, at least for mono-disperse granular material freely outflowing at a constant rate. A major draw-back of these small-scale DEM studies is that the initial bulk porosity of the simulated granular material is significantly higher than that of broken, prismatic rock. In this investigation, more

  5. Deformation of nanocrystalline materials by molecular-dynamics simulation: relationship to experiments?

    International Nuclear Information System (INIS)

    Wolf, D.; Yamakov, V.; Phillpot, S.R.; Mukherjee, A.; Gleiter, H.

    2005-01-01

    We review the results of recent molecular-dynamics simulations of the structure and deformation behavior of nanocrystalline materials, i.e., polycrystalline materials with a grain size of typically less than about 100 nm. These simulations have now become large enough and sophisticated enough that they are beginning to cover the entire range of grain sizes over which the experimentally suggested transition from a dislocation-based deformation mechanism to one involving GB processes takes place. Their atomic-level resolution provides novel insights into the intricate interplay between the dislocation and GB processes responsible for this crossover. These simulations also reveal how and why this crossover in the dominant mechanism leads to a transition in the mechanical behavior. However, in spite of these early successes, these simulations are inherently limited to rather idealized model microstructures and extremely high deformation rates. We therefore address the critical question as to the degree to which they begin to capture the experimentally observed, albeit controversial, deformation behavior of real nanocrystalline materials. (Supplementary material to this article, in the form of color graphs of some of the figures and several deformation-simulation movies, can be viewed at http://phillpot.mse.ufl.edu/review.html.)

  6. Effects of Phase Transformations and Dynamic Material Strength on Hydrodynamic Instability Evolution in Metals

    Science.gov (United States)

    Opie, Saul

    Hydrodynamic phenomena such as the Rayleigh-Taylor (RT) and Richtmyer-Meshkov (RM) instabilities can be described by exponential/linear growth of surface perturbations at a bimaterial interface when subjected to constant/impulsive acceleration. A challenge in designing systems to mitigate or exploit these effects is the lack of accurate material models at large dynamic strain rates and pressures. In particular, little stress-strain constitutive information at large strain rates and pressures is available for transient material phases formed at high pressures, and the continuum effect the phase transformation process has on the instability evolution. In this work, a phase-aware isotropic strength model is developed and partially validated with a novel RM-based instability experiment in addition to existing data from the literature. With the validated material model additional simulations are performed to provide insight into to the role that robust material constitutive behavior (e.g., pressure, temperature, rate dependence) has on RM instability and how RM instability experiments can be used to characterize and validated expected material behavior. For phase aware materials, particularly iron in this work, the simulations predict a strong dependence on the Atwood number that single phase materials do not have. At Atwood numbers close to unity, and pressures in the high pressure stability region, the high pressure phase dominates the RM evolution. However, at Atwood numbers close to negative one, the RM evolution is only weakly affected by the high-pressure phase even for shocks well above the phase transformation threshold. In addition to RM evolution this work looks at the closely related shock front perturbation evolution. Existing analytical models for isentropic processes in gases and liquids are modified for metal equation of states and plastic behavior for the first time. It is found that the presence of a volume collapsing phase transformation with increased

  7. Dynamics of pre-strained bi-material elastic systems linearized three-dimensional approach

    CERN Document Server

    Akbarov, Surkay D

    2015-01-01

    This book deals with dynamics of pre-stressed or pre-strained bi-material elastic systems consisting of stack of pre-stressed layers, stack of pre-stressed layers and pre-stressed half space (or half plane), stack of pre-stressed layers as well as absolute rigid foundation, pre-stressed compound solid and hollow cylinders and pre-stressed sandwich hollow cylinders. The problems considered in the book relate to the dynamics of a moving and oscillating moving load, forced vibration caused by linearly located or point located time-harmonic forces acting to the foregoing systems. Moreover, a considerable part of the book relate to the problems regarding the near surface, torsional and axisymmetric longitudinal waves propagation and dispersion in the noted above bi-material elastic systems. The book carries out the investigations within the framework of the piecewise homogeneous body model with the use of the Three-Dimensional Linearized Theory of Elastic Waves in Initially Stressed Bodies.

  8. A nonlinear dynamical system approach for the yielding behaviour of a viscoplastic material.

    Science.gov (United States)

    Burghelea, Teodor; Moyers-Gonzalez, Miguel; Sainudiin, Raazesh

    2017-03-08

    A nonlinear dynamical system model that approximates a microscopic Gibbs field model for the yielding of a viscoplastic material subjected to varying external stresses recently reported in R. Sainudiin, M. Moyers-Gonzalez and T. Burghelea, Soft Matter, 2015, 11(27), 5531-5545 is presented. The predictions of the model are in fair agreement with microscopic simulations and are in very good agreement with the micro-structural semi-empirical model reported in A. M. V. Putz and T. I. Burghelea, Rheol. Acta, 2009, 48, 673-689. With only two internal parameters, the nonlinear dynamical system model captures several key features of the solid-fluid transition observed in experiments: the effect of the interactions between microscopic constituents on the yield point, the abruptness of solid-fluid transition and the emergence of a hysteresis of the micro-structural states upon increasing/decreasing external forces. The scaling behaviour of the magnitude of the hysteresis with the degree of the steadiness of the flow is consistent with previous experimental observations. Finally, the practical usefulness of the approach is demonstrated by fitting a rheological data set measured with an elasto-viscoplastic material.

  9. Novel dynamic thermal characterization of multifunctional concretes with microencapsulated phase change materials

    Science.gov (United States)

    Pisello, Anna Laura; Fabiani, Claudia; D'Alessandro, Antonella; Cabeza, Luisa F.; Ubertini, Filippo; Cotana, Franco

    2017-04-01

    Concrete is widely applied in the construction sector for its reliable mechanical performance, its easiness of use and low costs. It also appears promising for enhancing the thermal-energy behavior of buildings thanks to its capability to be doped with multifunctional fillers. In fact, key studies acknowledged the benefits of thermally insulated concretes for applications in ceilings and walls. At the same time, thermal capacity also represents a key property to be optimized, especially for lightweight constructions. In this view, Thermal-Energy Storage (TES) systems have been recently integrated into building envelopes for increasing thermal inertia. More in detail, numerical experimental investigations showed how Phase Change materials (PCMs), as an acknowledged passive TES strategy, can be effectively included in building envelope, with promising results in terms of thermal buffer potentiality. In particular, this work builds upon previous papers aimed at developing the new PCM-filled concretes for structural applications and optimized thermalenergy efficiency, and it is focused on the development of a new experimental method for testing such composite materials in thermal-energy dynamic conditions simulated in laboratory by exposing samples to environmentally controlled microclimate while measuring thermal conductivity and diffusivity by means of transient plane source techniques. The key findings show how the new composites are able to increasingly delay the thermal wave with increasing the PCM concentration and how the thermal conductivity varies during the course of the phase change, in both melting and solidification processes. The new analysis produces useful findings in proposing an effective method for testing composite materials with adaptive thermal performance, much needed by the scientific community willing to study building envelopes dynamics.

  10. Multi-scale calculation based on dual domain material point method combined with molecular dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Dhakal, Tilak Raj [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-27

    This dissertation combines the dual domain material point method (DDMP) with molecular dynamics (MD) in an attempt to create a multi-scale numerical method to simulate materials undergoing large deformations with high strain rates. In these types of problems, the material is often in a thermodynamically non-equilibrium state, and conventional constitutive relations are often not available. In this method, the closure quantities, such as stress, at each material point are calculated from a MD simulation of a group of atoms surrounding the material point. Rather than restricting the multi-scale simulation in a small spatial region, such as phase interfaces, or crack tips, this multi-scale method can be used to consider non-equilibrium thermodynamic e ects in a macroscopic domain. This method takes advantage that the material points only communicate with mesh nodes, not among themselves; therefore MD simulations for material points can be performed independently in parallel. First, using a one-dimensional shock problem as an example, the numerical properties of the original material point method (MPM), the generalized interpolation material point (GIMP) method, the convected particle domain interpolation (CPDI) method, and the DDMP method are investigated. Among these methods, only the DDMP method converges as the number of particles increases, but the large number of particles needed for convergence makes the method very expensive especially in our multi-scale method where we calculate stress in each material point using MD simulation. To improve DDMP, the sub-point method is introduced in this dissertation, which provides high quality numerical solutions with a very small number of particles. The multi-scale method based on DDMP with sub-points is successfully implemented for a one dimensional problem of shock wave propagation in a cerium crystal. The MD simulation to calculate stress in each material point is performed in GPU using CUDA to accelerate the

  11. Drop Weight Device Fabrication and Tests for a Dynamic Material Property of Shock-Absorbing Material and Structure in Transportation Package

    International Nuclear Information System (INIS)

    Choi, Woo Seok; Jeon, Jea Eon; Han, Sang Hyeok; Lee, Sang Hoon; Seo, Ki Seok

    2009-01-01

    A radioactive material transportation package consists of canister and impact limiters. IAEA Safety Standard Series No. TS-R-1 recommends a drop test to evaluate the structural integrity of a transportation package under a hypothetical accident condition. The free drop test of a transportation package from 9 m height simulates one of accident conditions. The transportation package has a potential energy corresponding to 9 m drop height, and this energy changes to a kinetic energy when it impacts on the target. The energy is absorbed by a deformation of shock-absorbing material so that the minimum energy is transferred to canister. Accordingly, the shock-absorbing material is a very important part in transportation package design. Since the data for shock-absorbing material characteristics is acquired by a static test in general, it is quite different to that of dynamic characteristics. And the dynamic characteristics data is hardly found in literature. In this study, a drop weight facility was designed and fabricated which produces an impact speed like that of free drop of 9 m height. Several materials considered for an impact limiter and impact limiter structures were tested by a drop weight facility to acquire a dynamic material characteristics data

  12. Drop Weight Device Fabrication and Tests for a Dynamic Material Property of Shock-Absorbing Material and Structure in Transportation Package

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Woo Seok; Jeon, Jea Eon; Han, Sang Hyeok; Lee, Sang Hoon; Seo, Ki Seok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2009-05-15

    A radioactive material transportation package consists of canister and impact limiters. IAEA Safety Standard Series No. TS-R-1 recommends a drop test to evaluate the structural integrity of a transportation package under a hypothetical accident condition. The free drop test of a transportation package from 9 m height simulates one of accident conditions. The transportation package has a potential energy corresponding to 9 m drop height, and this energy changes to a kinetic energy when it impacts on the target. The energy is absorbed by a deformation of shock-absorbing material so that the minimum energy is transferred to canister. Accordingly, the shock-absorbing material is a very important part in transportation package design. Since the data for shock-absorbing material characteristics is acquired by a static test in general, it is quite different to that of dynamic characteristics. And the dynamic characteristics data is hardly found in literature. In this study, a drop weight facility was designed and fabricated which produces an impact speed like that of free drop of 9 m height. Several materials considered for an impact limiter and impact limiter structures were tested by a drop weight facility to acquire a dynamic material characteristics data.

  13. Dynamical Effects in Metal-Organic Frameworks: The Microporous Materials as Shock Absorbers

    Science.gov (United States)

    Banlusan, Kiettipong; Strachan, Alejandro

    2017-06-01

    Metal-organic frameworks (MOFs) are a class of nano-porous crystalline solids consisting of inorganic units coordinated to organic linkers. The unique molecular structures and outstanding properties with ultra-high porosity and tunable chemical functionality by various choices of metal clusters and organic ligands make this class of materials attractive for many applications. The complex and quite unique responses of these materials to mechanical loading including void collapse make them attractive for applications in energy absorption and storage. We will present using large-scale molecular dynamics simulations to investigate shock propagation in zeolitic imidazolate framework ZIF-8 and MOF-5. We find that for shock strengths above a threshold a two-wave structure develops with a leading elastic precursor followed by a second wave of structural collapse to relax the stress. Structural transition of MOFs in response to shock waves corresponds to the transition between two Hugoniot curves, and results in abrupt change in temperature. The pore-collapse wave propagates at slower velocity than the leading wave and weakens it, resulting in shock attenuation. Increasing piston speed results in faster propagation of pore-collapse wave, but the leading elastic wave remains unchanged below the overdriven regime. We discuss how the molecular structure of the MOFs and shock propagation direction affect the response of the materials and their ability to weaken shocks. Office of Naval Research, MURI 2012 02341 01.

  14. Time-resolved x-ray diffraction techniques for bulk polycrystalline materials under dynamic loading

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, P. K.; Hustedt, C. J.; Zhao, M.; Ananiadis, A. G.; Hufnagel, T. C. [Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Vecchio, K. S. [Department of NanoEngineering, University of California San Diego, La Jolla, California 92093 (United States); Huskins, E. L. [Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee 37830 (United States); US Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, Maryland 21005 (United States); Casem, D. T. [US Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, Maryland 21005 (United States); Gruner, S. M. [Department of Physics, Cornell University, Ithaca, New York 14853 (United States); Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, New York 14853 (United States); Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, New York 14853 (United States); Tate, M. W.; Philipp, H. T.; Purohit, P.; Weiss, J. T. [Department of Physics, Cornell University, Ithaca, New York 14853 (United States); Woll, A. R. [Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, New York 14853 (United States); Kannan, V.; Ramesh, K. T. [Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Kenesei, P.; Okasinski, J. S.; Almer, J. [X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

    2014-09-15

    We have developed two techniques for time-resolved x-ray diffraction from bulk polycrystalline materials during dynamic loading. In the first technique, we synchronize a fast detector with loading of samples at strain rates of ∼10{sup 3}–10{sup 4} s{sup −1} in a compression Kolsky bar (split Hopkinson pressure bar) apparatus to obtain in situ diffraction patterns with exposures as short as 70 ns. This approach employs moderate x-ray energies (10–20 keV) and is well suited to weakly absorbing materials such as magnesium alloys. The second technique is useful for more strongly absorbing materials, and uses high-energy x-rays (86 keV) and a fast shutter synchronized with the Kolsky bar to produce short (∼40 μs) pulses timed with the arrival of the strain pulse at the specimen, recording the diffraction pattern on a large-format amorphous silicon detector. For both techniques we present sample data demonstrating the ability of these techniques to characterize elastic strains and polycrystalline texture as a function of time during high-rate deformation.

  15. Dynamic simulations of geologic materials using combined FEM/DEM/SPH analysis

    Energy Technology Data Exchange (ETDEWEB)

    Morris, J P; Johnson, S M

    2008-03-26

    An overview of the Lawrence Discrete Element Code (LDEC) is presented, and results from a study investigating the effect of explosive and impact loading on geologic materials using the Livermore Distinct Element Code (LDEC) are detailed. LDEC was initially developed to simulate tunnels and other structures in jointed rock masses using large numbers of polyhedral blocks. Many geophysical applications, such as projectile penetration into rock, concrete targets, and boulder fields, require a combination of continuum and discrete methods in order to predict the formation and interaction of the fragments produced. In an effort to model this class of problems, LDEC now includes implementations of Cosserat point theory and cohesive elements. This approach directly simulates the transition from continuum to discontinuum behavior, thereby allowing for dynamic fracture within a combined finite element/discrete element framework. In addition, there are many application involving geologic materials where fluid-structure interaction is important. To facilitate solution of this class of problems a Smooth Particle Hydrodynamics (SPH) capability has been incorporated into LDEC to simulate fully coupled systems involving geologic materials and a saturating fluid. We will present results from a study of a broad range of geomechanical problems that exercise the various components of LDEC in isolation and in tandem.

  16. Nonlinear dynamic modeling for smart material electro-hydraulic actuator development

    Science.gov (United States)

    Larson, John P.; Dapino, Marcelo J.

    2013-03-01

    Smart material electro-hydraulic actuators use hydraulic rectification by one-way check valves to amplify the motion of smart materials, such as magnetostrictives and piezoelectrics, in order to create compact, lightweight actuators. A piston pump driven by a smart material is combined with a hydraulic cylinder to form a self-contained, power-by-wire actuator that can be used in place of a conventional hydraulic system without the need for hydraulic lines and a centralized pump. The performance of an experimental actuator driven by a 12.7 mm diameter, 114 mm length Terfenol-D rod is evaluated over a range of applied input frequencies, loads, and currents. The peak performance achieved is 37 W, moving a 220 N load at a rate of 17 cm/s and producing a blocked pressure of 12.5 MPa. Additional tests are conducted to quantify the dynamic behavior of the one-way reed valves using a scanning laser vibrometer to identify the frequency response of the reeds and the effect of the valve seat and fluid mass loading. A lumped-parameter model is developed for the system that includes valve inertia and fluid response nonlinearities, and the model results are compared with the experimental data.

  17. Testing and modeling the dynamic response of foam materials for blast protection

    Science.gov (United States)

    Fitek, John H.

    The pressure wave released from an explosion can cause injury to the lungs. A personal armor system concept for blast lung injury protection consists of a polymer foam layer behind a rigid armor plate to be worn over the chest. This research develops a method for testing and modeling the dynamic response of foam materials to be used for down-selection of materials for this application. Constitutive equations for foam materials are incorporated into a lumped parameter model of the combined armor plate and foam system. Impact testing and shock tube testing are used to measure the foam model parameters and validate the model response to a pressure wave load. The plate and foam armor model is then coupled to a model of the human thorax. With a blast pressure wave input, the armor model is evaluated based on how it affects the injury-causing mechanism of chest wall motion. Results show that to reduce chest wall motion, the foam must compress at a relatively constant stress level, which requires a sufficient foam thickness.

  18. Magnetic materials at finite temperatures: thermodynamics and combined spin and molecular dynamics derived from first principles calculations

    International Nuclear Information System (INIS)

    Eisenbach, Markus; Perera, Meewanage Dilina N.; Landau, David P; Nicholson, Don M.; Yin, Junqi; Brown, Greg

    2015-01-01

    We present a unified approach to describe the combined behavior of the atomic and magnetic degrees of freedom in magnetic materials. Using Monte Carlo simulations directly combined with first principles the Curie temperature can be obtained ab initio in good agreement with experimental values. The large scale constrained first principles calculations have been used to construct effective potentials for both the atomic and magnetic degrees of freedom that allow the unified study of influence of phonon-magnon coupling on the thermodynamics and dynamics of magnetic systems. The MC calculations predict the specific heat of iron in near perfect agreement with experimental results from 300K to above Tc and allow the identification of the importance of the magnon-phonon interaction at the phase-transition. Further Molecular Dynamics and Spin Dynamics calculations elucidate the dynamics of this coupling and open the potential for quantitative and predictive descriptions of dynamic structure factors in magnetic materials using first principles-derived simulations.

  19. 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.

  20. Molecular dynamics simulations of interactions between hydrogen and fusion-relevant materials

    International Nuclear Information System (INIS)

    Rooij, Dagmar de

    2010-01-01

    In a thermonuclear reactor fusion between hydrogen isotopes takes place, producing helium and energy. The so-called divertor is the part of the fusion reactor vessel where the plasma is neutralized in order to exhaust the helium. The surface plates of the divertor are subjected to high heat loads and high fluxes of energetic hydrogen and helium. In the next generation fusion device - the tokamak ITER - the expected conditions at the plates are particle fluxes exceeding 10 24 per second and square metre, particle energies ranging from 1 to 100 eV and an average heat load of 10 MW per square metre. Two materials have been identified as candidates for the ITER divertor plates: carbon and tungsten. Since there are currently no fusion devices that can create these harsh conditions, it is unknown how the materials will behave in terms of erosion and hydrogen retention. To gain more insight in the physical processes under these conditions molecular dynamics simulations have been conducted. Since diamond has been proposed as possible plasma facing material, we have studied erosion and hydrogen retention in diamond and amorphous hydrogenated carbon (a-C:H). As in experiments, diamond shows a lower erosion yield than a-C:H, however the hydrogen retention in diamond is much larger than in a-C:H and also hardly depending on the substrate temperature. This implies that simple heating of the surface is not sufficient to retrieve the hydrogen from diamond material, whereas a-C:H readily releases the retained hydrogen. So, in spite of the higher erosion yield carbon material other than diamond seems more suitable. Experiments suggest that the erosion yield of carbon material decreases with increasing flux. This was studied in our simulations. The results show no flux dependency, suggesting that the observed reduction is not a material property but is caused by external factors as, for example, redeposition of the erosion products. Our study of the redeposition showed that the

  1. Materials science. Dynamic mechanical behavior of multilayer graphene via supersonic projectile penetration.

    Science.gov (United States)

    Lee, Jae-Hwang; Loya, Phillip E; Lou, Jun; Thomas, Edwin L

    2014-11-28

    Multilayer graphene is an exceptional anisotropic material due to its layered structure composed of two-dimensional carbon lattices. Although the intrinsic mechanical properties of graphene have been investigated at quasi-static conditions, its behavior under extreme dynamic conditions has not yet been studied. We report the high-strain-rate behavior of multilayer graphene over a range of thicknesses from 10 to 100 nanometers by using miniaturized ballistic tests. Tensile stretching of the membrane into a cone shape is followed by initiation of radial cracks that approximately follow crystallographic directions and extend outward well beyond the impact area. The specific penetration energy for multilayer graphene is ~10 times more than literature values for macroscopic steel sheets at 600 meters per second. Copyright © 2014, American Association for the Advancement of Science.

  2. Ab Initio Molecular-Dynamics Simulation of Neuromorphic Computing in Phase-Change Memory Materials.

    Science.gov (United States)

    Skelton, Jonathan M; Loke, Desmond; Lee, Taehoon; Elliott, Stephen R

    2015-07-08

    We present an in silico study of the neuromorphic-computing behavior of the prototypical phase-change material, Ge2Sb2Te5, using ab initio molecular-dynamics simulations. Stepwise changes in structural order in response to temperature pulses of varying length and duration are observed, and a good reproduction of the spike-timing-dependent plasticity observed in nanoelectronic synapses is demonstrated. Short above-melting pulses lead to instantaneous loss of structural and chemical order, followed by delayed partial recovery upon structural relaxation. We also investigate the link between structural order and electrical and optical properties. These results pave the way toward a first-principles understanding of phase-change physics beyond binary switching.

  3. Quasi-dynamic Material Flow Analysis applied to the Austrian Phosphorus cycle

    Science.gov (United States)

    Zoboli, Ottavia; Rechberger, Helmut

    2013-04-01

    Phosphorus (P) is one of the key elements that sustain life on earth and that allow achieving the current high levels of food production worldwide. It is a non-renewable resource, without any existing substitute. Because of its current dissipative use by mankind and to its very slow geochemical cycle, this resource is rapidly depleting and it is strongly connected to the problem of ensuring food security. Moreover P is also associated to important environmental problems. Its extraction often generates hazardous wastes, while its accumulation in water bodies can lead to eutrophication, with consequent severe ecological damages. It is therefore necessary to analyze and understand in detail the system of P, in regard to its use and management, to identify the processes that should be targeted in order to reduce the overall consumption of this resource. This work aims at establishing a generic quasi-dynamic model, which describes the Austrian P-budget and which allows investigating the trends of P use in the past, but also selected future scenarios. Given the importance of P throughout the whole anthropogenic metabolism, the model is based on a comprehensive system that encompasses several economic sectors, from agriculture and animal husbandry to industry, consumption and waste and wastewater treatment. Furthermore it includes the hydrosphere, to assess the losses of P into water bodies, due to the importance of eutrophication problems. The methodology applied is Material Flow Analysis (MFA), which is a systemic approach to assess and balance the stocks and flows of a material within a system defined in space and time. Moreover the model is integrated in the software STAN, a freeware tailor-made for MFA. Particular attention is paid to the characteristics and the quality of the data, in order to include data uncertainty and error propagation in the dynamic balance.

  4. Effect of a Material Contrast on a Dynamic Rupture: 3-D

    Science.gov (United States)

    Harris, R. A.; Day, S. M.

    2003-12-01

    We use numerical simulations of spontaneously propagating ruptures to examine the effect of a material contrast on earthquake dynamics. We specifically study the case of a lateral contrast whereby the fault is the boundary between two different rock-types. This scenario was previously studied in two-dimensions by Harris and Day [BSSA, 1997], and Andrews and Ben-Zion [JGR, 1997], in addition to subsequent 2-D studies, but it has not been known if the two-dimensional results are applicable to the real three-dimensional world. The addition of the third dimension implies a transition from pure mode II (i.e., plane-strain) to mixed-mode crack dynamics, which is more complicated since in mode II the shear and normal stresses are coupled whereas in mode III (i.e., anti-plane strain) they are not coupled. We use a slip-weakening fracture criterion and examine the effect on an earthquake rupture of material contrasts of up to 50 percent across the fault zone. We find a surprisingly good agreement between our earlier 2-D results, and our 3-D results for along-strike propagation. We find that the analytical solution presented in Harris and Day [BSSA, 1997] does an excellent job at predicting the bilateral, along-strike rupture velocities for the three-dimensional situation. In contrast, the along-dip propagation behaves much as expected for a purely mode-III rupture, with the rupture velocities up-dip and down-dip showing the expected symmetries.

  5. Comparative study of two materials for dynamic hip screw during fall and gait loading: titanium alloy and stainless steel.

    Science.gov (United States)

    Taheri, Nooshin S; Blicblau, Aaron S; Singh, Manmohan

    2011-11-01

    Internal fixation with dynamic hip screw is a choice of treatment for hip fractures to stabilize a femoral fracture. Choosing the proper implant and its material has a great effect on the healing process and failure prevention. The purpose of this analysis was to assess biomechanical behavior of dynamic hip screw with two different materials implanted in the femur during fall and gait. A 3D finite element model of an intact femur and a 3D implant within the same femur were developed. A finite element analysis was carried out to establish the effect of load conditions and implant material properties on biomechanical behavior of the dynamic hip screw after internal fixation. Two load configurations are chosen: one simulating the stance phase of the normal gait cycle, and the other replicating a low-energy fall. The implanted femur was investigated with two different materials for the dynamic hip screw: stainless steel and titanium alloy. During stance, more stress is placed on the implanted femur compared with the intact femur. During a fall, the implanted femur is in a greater state of stress, which mostly occurs inside the dynamic hip screw. Titanium alloy decreases stress levels by an average of 40% compared with stainless steel. However, deformation is slightly reduced with a stainless steel dynamic hip screw during both load cases. After internal fixation, dynamic hip screw generates greater stresses within the implanted femur compared with the intact femur under the same loading conditions. A titanium alloy implant appears to undergo less stress from a low-energy fall compared with stainless steel and can be considered the preferred implant material. The critical parts of the dynamic hip screw are the forth distal screw and the plate.

  6. Structural predictions for Correlated Electron Materials Using the Functional Dynamical Mean Field Theory Approach

    Science.gov (United States)

    Haule, Kristjan

    2018-04-01

    The Dynamical Mean Field Theory (DMFT) in combination with the band structure methods has been able to address reach physics of correlated materials, such as the fluctuating local moments, spin and orbital fluctuations, atomic multiplet physics and band formation on equal footing. Recently it is getting increasingly recognized that more predictive ab-initio theory of correlated systems needs to also address the feedback effect of the correlated electronic structure on the ionic positions, as the metal-insulator transition is almost always accompanied with considerable structural distortions. We will review recently developed extension of merger between the Density Functional Theory (DFT) and DMFT method, dubbed DFT+ embedded DMFT (DFT+eDMFT), whichsuccessfully addresses this challenge. It is based on the stationary Luttinger-Ward functional to minimize the numerical error, it subtracts the exact double-counting of DFT and DMFT, and implements self-consistent forces on all atoms in the unit cell. In a few examples, we will also show how the method elucidated the important feedback effect of correlations on crystal structure in rare earth nickelates to explain the mechanism of the metal-insulator transition. The method showed that such feedback effect is also essential to understand the dynamic stability of the high-temperature body-centered cubic phase of elemental iron, and in particular it predicted strong enhancement of the electron-phonon coupling over DFT values in FeSe, which was very recently verified by pioneering time-domain experiment.

  7. 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...

  8. Visualizing electron dynamics in organic materials: Charge transport through molecules and angular resolved photoemission

    Science.gov (United States)

    Kümmel, Stephan

    Being able to visualize the dynamics of electrons in organic materials is a fascinating perspective. Simulations based on time-dependent density functional theory allow to realize this hope, as they visualize the flow of charge through molecular structures in real-space and real-time. We here present results on two fundamental processes: Photoemission from organic semiconductor molecules and charge transport through molecular structures. In the first part we demonstrate that angular resolved photoemission intensities - from both theory and experiment - can often be interpreted as a visualization of molecular orbitals. However, counter-intuitive quantum-mechanical electron dynamics such as emission perpendicular to the direction of the electrical field can substantially alter the picture, adding surprising features to the molecular orbital interpretation. In a second study we calculate the flow of charge through conjugated molecules. The calculations show in real time how breaks in the conjugation can lead to a local buildup of charge and the formation of local electrical dipoles. These can interact with neighboring molecular chains. As a consequence, collections of ''molecular electrical wires'' can show distinctly different characteristics than ''classical electrical wires''. German Science Foundation GRK 1640.

  9. Dynamic mean field theory for lattice gas models of fluid mixtures confined in mesoporous materials.

    Science.gov (United States)

    Edison, J R; Monson, P A

    2013-11-12

    We present the extension of dynamic mean field theory (DMFT) for fluids in porous materials (Monson, P. A. J. Chem. Phys. 2008, 128, 084701) to the case of mixtures. The theory can be used to describe the relaxation processes in the approach to equilibrium or metastable equilibrium states for fluids in pores after a change in the bulk pressure or composition. It is especially useful for studying systems where there are capillary condensation or evaporation transitions. Nucleation processes associated with these transitions are emergent features of the theory and can be visualized via the time dependence of the density distribution and composition distribution in the system. For mixtures an important component of the dynamics is relaxation of the composition distribution in the system, especially in the neighborhood of vapor-liquid interfaces. We consider two different types of mixtures, modeling hydrocarbon adsorption in carbon-like slit pores. We first present results on bulk phase equilibria of the mixtures and then the equilibrium (stable/metastable) behavior of these mixtures in a finite slit pore and an inkbottle pore. We then use DMFT to describe the evolution of the density and composition in the pore in the approach to equilibrium after changing the state of the bulk fluid via composition or pressure changes.

  10. CERN antiproton target: Hydrocode analysis of its core material dynamic response under proton beam impact

    Directory of Open Access Journals (Sweden)

    Claudio Torregrosa Martin

    2016-07-01

    Full Text Available 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.

  11. Numerical Simulation of the Dynamic Performance of the Ceramic Material Affected by Different Strain Rate and Porosity

    International Nuclear Information System (INIS)

    Wang Zhen; Mei, H; Lai, X; Liu, L S; Zhai, P C; Cao, D F

    2013-01-01

    Ceramic materials are frequently used in protective armor applications for its low-density, high elastic modulus and high strength. It may be subject to different ballistic impacts in many situations, thus many studies have been carried out to explore the approach to improve the mechanical properties of the ceramic material. However, the materials manufactured in real world are full of defects, which would involve in variable fractures or damage. Therefore, the defects should be taken into account while the simulations are performed. In this paper, the dynamic properties of ceramic materials (Al 2 O 3 ) affected by different strain rate (500–5000) and porosity (below 5%) are investigated. Foremost, the effect of strain rate was studied by using different load velocities. Then, compression simulations are performed by setting different porosities and random distribution of pores size and location in ceramic materials. Crack extensions and failure modes are observed to describe the dynamic mechanical behavior.

  12. Molecular dynamics study of water molecule diffusion in oil-paper insulation materials

    International Nuclear Information System (INIS)

    Liao Ruijin; Zhu Mengzhao; Yang Lijun; Zhou Xin; Gong Chunyan

    2011-01-01

    Moisture is an important factor that influences the safe operation of transformers. In this study, molecular dynamics was employed to investigate the diffusion behavior of water molecules in the oil-paper insulation materials of transformers. Two oil-cellulose models were built. In the first model, water molecules were initially distributed in oil, and in the second model, water molecules were distributed in cellulose. The non-bonding energies of interaction between water molecules and oil, and between water molecules and cellulose, were calculated by the Dreiding force field. The interaction energy was found to play a dominant role in influencing the equilibrium distribution of water molecules. The radial direction functions of water molecules toward oil and cellulose indicate that the hydrogen bonds between water molecules and cellulose are sufficiently strong to withstand the operating temperature of the transformer. Mean-square displacement analysis of water molecules diffusion suggests that water molecules initially distributed in oil showed anisotropic diffusion; they tended to diffuse toward cellulose. Water molecules initially distributed in cellulose diffused isotropically. This study provides a theoretical contribution for improvements in online monitoring of water in transformers, and for subsequent research on new insulation materials.

  13. Molecular dynamics study of water molecule diffusion in oil-paper insulation materials

    Energy Technology Data Exchange (ETDEWEB)

    Liao Ruijin [State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University, Chongqing 400044 (China); Zhu Mengzhao, E-mail: xiaozhupost@163.co [State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University, Chongqing 400044 (China); Yang Lijun; Zhou Xin; Gong Chunyan [State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University, Chongqing 400044 (China)

    2011-03-01

    Moisture is an important factor that influences the safe operation of transformers. In this study, molecular dynamics was employed to investigate the diffusion behavior of water molecules in the oil-paper insulation materials of transformers. Two oil-cellulose models were built. In the first model, water molecules were initially distributed in oil, and in the second model, water molecules were distributed in cellulose. The non-bonding energies of interaction between water molecules and oil, and between water molecules and cellulose, were calculated by the Dreiding force field. The interaction energy was found to play a dominant role in influencing the equilibrium distribution of water molecules. The radial direction functions of water molecules toward oil and cellulose indicate that the hydrogen bonds between water molecules and cellulose are sufficiently strong to withstand the operating temperature of the transformer. Mean-square displacement analysis of water molecules diffusion suggests that water molecules initially distributed in oil showed anisotropic diffusion; they tended to diffuse toward cellulose. Water molecules initially distributed in cellulose diffused isotropically. This study provides a theoretical contribution for improvements in online monitoring of water in transformers, and for subsequent research on new insulation materials.

  14. Selection of high temperature thermal energy storage materials for advanced solar dynamic space power systems

    Science.gov (United States)

    Lacy, Dovie E.; Coles-Hamilton, Carolyn; Juhasz, Albert

    1987-01-01

    Under the direction of NASA's Office of Aeronautics and Technology (OAST), the NASA Lewis Research Center has initiated an in-house thermal energy storage program to identify combinations of phase change thermal energy storage media for use with a Brayton and Stirling Advanced Solar Dynamic (ASD) space power system operating between 1070 and 1400 K. A study has been initiated to determine suitable combinations of thermal energy storage (TES) phase change materials (PCM) that result in the smallest and lightest weight ASD power system possible. To date the heats of fusion of several fluoride salt mixtures with melting points greater than 1025 K have been verified experimentally. The study has indicated that these salt systems produce large ASD systems because of their inherent low thermal conductivity and low density. It is desirable to have PCMs with high densities and high thermal conductivities. Therefore, alternate phase change materials based on metallic alloy systems are also being considered as possible TES candidates for future ASD space power systems.

  15. Influence of non-collisional laser heating on the electron dynamics in dielectric materials

    Science.gov (United States)

    Barilleau, L.; Duchateau, G.; Chimier, B.; Geoffroy, G.; Tikhonchuk, V.

    2016-12-01

    The electron dynamics in dielectric materials induced by intense femtosecond laser pulses is theoretically addressed. The laser driven temporal evolution of the energy distribution of electrons in the conduction band is described by a kinetic Boltzmann equation. In addition to the collisional processes for energy transfer such as electron-phonon-photon and electron-electron interactions, a non-collisional process for photon absorption in the conduction band is included. It relies on direct transitions between sub-bands of the conduction band through multiphoton absorption. This mechanism is shown to significantly contribute to the laser heating of conduction electrons for large enough laser intensities. It also increases the time required for the electron distribution to reach the equilibrium state as described by the Fermi-Dirac statistics. Quantitative results are provided for quartz irradiated by a femtosecond laser pulse with a wavelength of 800 nm and for intensities in the range of tens of TW cm-2, lower than the ablation threshold. The change in the energy deposition induced by this non-collisional heating process is expected to have a significant influence on the laser processing of dielectric materials.

  16. Physics of the Kitaev Model: Fractionalization, Dynamic Correlations, and Material Connections

    Science.gov (United States)

    Hermanns, M.; Kimchi, I.; Knolle, J.

    2018-03-01

    Quantum spin liquids have fascinated condensed matter physicists for decades because of their unusual properties such as spin fractionalization and long-range entanglement. Unlike conventional symmetry breaking, the topological order underlying quantum spin liquids is hard to detect experimentally. Even theoretical models are scarce for which the ground state is established to be a quantum spin liquid. The Kitaev honeycomb model and its generalizations to other tricoordinated lattices are chief counterexamples - they are exactly solvable, harbor a variety of quantum spin liquid phases, and are also relevant for certain transition metal compounds including the polymorphs of (Na,Li)2IrO3 iridates and RuCl3. In this review, we give an overview of the rich physics of the Kitaev model, including two-dimensional and three-dimensional fractionalization as well as dynamic correlations and behavior at finite temperatures. We discuss the different materials and argue how the Kitaev model physics can be relevant even though most materials show magnetic ordering at low temperatures.

  17. Emergency material allocation with time-varying supply-demand based on dynamic optimization method for river chemical spills.

    Science.gov (United States)

    Liu, Jie; Guo, Liang; Jiang, Jiping; Jiang, Dexun; Wang, Peng

    2018-04-13

    Aiming to minimize the damage caused by river chemical spills, efficient emergency material allocation is critical for an actual emergency rescue decision-making in a quick response. In this study, an emergency material allocation framework based on time-varying supply-demand constraint is developed to allocate emergency material, minimize the emergency response time, and satisfy the dynamic emergency material requirements in post-accident phases dealing with river chemical spills. In this study, the theoretically critical emergency response time is firstly obtained for the emergency material allocation system to select a series of appropriate emergency material warehouses as potential supportive centers. Then, an enumeration method is applied to identify the practically critical emergency response time, the optimum emergency material allocation and replenishment scheme. Finally, the developed framework is applied to a computational experiment based on south-to-north water transfer project in China. The results illustrate that the proposed methodology is a simple and flexible tool for appropriately allocating emergency material to satisfy time-dynamic demands during emergency decision-making. Therefore, the decision-makers can identify an appropriate emergency material allocation scheme in a balance between time-effective and cost-effective objectives under the different emergency pollution conditions.

  18. A Method to Estimate the Dynamic Displacement and Stress of a Multi-layered Pavement with Bituminous or Concrete Materials

    Directory of Open Access Journals (Sweden)

    Zheng LU

    2014-12-01

    Full Text Available In this research work, a method to estimate the dynamic characteristics of a multilayered pavement with bituminous or concrete materials is proposed. A mechanical model is established to investigate the dynamic displacement and stress of the multi-layered pavement structure. Both the flexible and the rigid pavements, corresponding to bituminous materials and concrete materials, respectively, are studied. The theoretical solutions of the multi-layered pavement structure are deduced considering the compatibility condition at the interface of the structural layers. By introducing FFT (Fast Fourier Transform algorithm, some numerical results are presented. Comparisons of the theoretical and experimental result implied that the proposed method is reasonable in predicting the stress and displacement of a multi-layered pavement with bituminous or concrete materials. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6071

  19. Nanoscale inhomogeneity and photoacid generation dynamics in extreme ultraviolet resist materials

    Science.gov (United States)

    Wu, Ping-Jui; Wang, Yu-Fu; Chen, Wei-Chi; Wang, Chien-Wei; Cheng, Joy; Chang, Vencent; Chang, Ching-Yu; Lin, John; Cheng, Yuan-Chung

    2018-03-01

    The development of extreme ultraviolet (EUV) lithography towards the 22 nm node and beyond depends critically on the availability of resist materials that meet stringent control requirements in resolution, line edge roughness, and sensitivity. However, the molecular mechanisms that govern the structure-function relationships in current EUV resist systems are not well understood. In particular, the nanoscale structures of the polymer base and the distributions of photoacid generators (PAGs) should play a critical roles in the performance of a resist system, yet currently available models for photochemical reactions in EUV resist systems are exclusively based on homogeneous bulk models that ignore molecular-level details of solid resist films. In this work, we investigate how microscopic molecular organizations in EUV resist affect photoacid generations in a bottom-up approach that describes structure-dependent electron-transfer dynamics in a solid film model. To this end, molecular dynamics simulations and stimulated annealing are used to obtain structures of a large simulation box containing poly(4-hydroxystyrene) (PHS) base polymers and triphenylsulfonium based PAGs. Our calculations reveal that ion-pair interactions govern the microscopic distributions of the polymer base and PAG molecules, resulting in a highly inhomogeneous system with nonuniform nanoscale chemical domains. Furthermore, the theoretical structures were used in combination of quantum chemical calculations and the Marcus theory to evaluate electron transfer rates between molecular sites, and then kinetic Monte Carlo simulations were carried out to model electron transfer dynamics with molecular structure details taken into consideration. As a result, the portion of thermalized electrons that are absorbed by the PAGs and the nanoscale spatial distribution of generated acids can be estimated. Our data reveal that the nanoscale inhomogeneous distributions of base polymers and PAGs strongly affect the

  20. Study of the adsorption of mercury (II) on lignocellulosic materials under static and dynamic conditions.

    Science.gov (United States)

    Arias Arias, Fabian E; Beneduci, Amerigo; Chidichimo, Francesco; Furia, Emilia; Straface, Salvatore

    2017-08-01

    WHO has declared mercury as one of the most dangerous pollutants for human health. Unfortunately, several cases of rivers and aquifers contaminated by mercury inevitably poses the problem on how to remediate them. Considerable efforts are being addressed to develop cost-effective methodologies, among which the use of low-cost adsorbing materials. In this paper, the adsorption performances of an alternative lignocellulosic material derived from the Spanish broom plant, are presented. This plant is widely diffused in the world and its usage for Hg(II) removal from water in real working conditions requires only minimal pretreatment steps. A thoroughly investigation on the kinetics and thermodynamics of Hg(II) adsorption on Spanish broom is presented, by using Hg(II) polluted aqueous solutions specifically prepared in order to simulate typical groundwater conditions. Several batch experiments, under static conditions, were carried out in order to evaluate the effect of pH, contact time, adsorbent dosage, initial concentration, temperature. A maximum adsorption capacity of 20 mg L -1 can be obtained at pH 5, following a pseudo second order kinetics. Moreover, adsorption experiments in dynamic conditions were carried out using Spanish broom filters. Interestingly, a systematic, unconventional double S-shape breakthrough curve was observed under different experimental conditions, revealing the occurrence of two adsorption processes with different time scales. This behavior has been fitted by a bimodal Thomas model which, unlike the single Thomas fitting, gives satisfactory results with the introduction of a new parameter related to the fraction of surface active sites involved in the adsorption processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. A model of shape memory materials with hierarchical twinning: statics and dynamics

    International Nuclear Information System (INIS)

    Saxena, A.; Bishop, A.R.; Wu, Y.; Lookman, T.

    1995-01-01

    We consider a model of shape memory materials in which hierarchical twinning near the habit plane (austenite-martensite interface) is a new and crucial ingredient. The model includes (1) a triple-well potential (φ 6 model) in local shear strain, (2) strain gradient terms up to second order in strain and fourth order in gradient, and (3) all symmetry allowed compositional fluctuation-induced strain gradient terms. The last term favors hierarchy which enables communication between macroscopic (cm) and microscopic (A) regions essential for shape memory. Hierarchy also stabilizes tweed formation (criss-cross patterns of twins). External stress or pressure modulates (''patterns'') the spacing of domain walls. Therefore the ''pattern'' is encoded in the modulated hierarchical variation of the depth and width of the twins. This hierarchy of length scales provides a related hierarchy of time scales and thus the possibility of non-exponential decay. The four processes of the complete shape memory cycle-write, record, erase and recall-are explained within this model. Preliminary results based on 2D molecular dynamics are shown for tweed and hierarchy formation. (orig.)

  2. 3D Multiphysical Modelling of Fluid Dynamics and Mass Transfer in Laser Welding of Dissimilar Materials

    Directory of Open Access Journals (Sweden)

    Jiazhou Wu

    2018-06-01

    Full Text Available A three-dimensional multiphysical transient model was developed to investigate keyhole formation, weld pool dynamics, and mass transfer in laser welding of dissimilar materials. The coupling of heat transfer, fluid flow, keyhole free surface evolution, and solute diffusion between dissimilar metals was simulated. The adaptive heat source model was used to trace the change of keyhole shape, and the Rayleigh scattering of the laser beam was considered. The keyhole wall was calculated using the fluid volume equation, primarily considering the recoil pressure induced by metal evaporation, surface tension, and hydrostatic pressure. Fluid flow, diffusion, and keyhole formation were considered simultaneously in mass transport processes. Welding experiments of 304L stainless steel and industrial pure titanium TA2 were performed to verify the simulation results. It is shown that spatters are shaped during the welding process. The thickness of the intermetallic reaction layer between the two metals and the diffusion of elements in the weld are calculated, which are important criteria for welding quality. The simulation results correspond well with the experimental results.

  3. The effects of sexually explicit material use on romantic relationship dynamics

    Science.gov (United States)

    Minarcik, Jenny; Wetterneck, Chad T.; Short, MARY B.

    2016-01-01

    Background and aims Pornography use has become increasingly common. Studies have shown that individuals who use sexually explicit materials (SEMs) report negative effects (Schneider, 2000b). However, Bridges (2008b) found that couples who use SEM together have higher relationship satisfaction than those who use SEM independently. A further investigation into various types of SEM use in relationships may highlight how SEM is related to various areas of couple satisfaction. Thus, the purpose of the current study is to examine the impact of SEM use related to different relationship dynamics. Methods The current study included a college and Internet sample of 296 participants divided into groups based upon the SEM use in relationships (i.e., SEM alone, SEM use with partner, and no SEM use). Results There were significant differences between groups in relationship satisfaction [F(2, 252) = 3.69, p = .026], intimacy [F(2, 252) = 7.95, p = intimacy [t(174) = 2.76, p = .006] based on the frequency of SEM use. Discussion Further exploration of the SEM use function in couples will provide greater understanding of its role in romantic relationships. PMID:27784182

  4. Digital signal processing for velocity measurements in dynamical material's behaviour studies

    International Nuclear Information System (INIS)

    Devlaminck, Julien; Luc, Jerome; Chanal, Pierre-Yves

    2014-01-01

    In this work, we describe different configurations of optical fiber interferometers (types Michelson and Mach-Zehnder) used to measure velocities during dynamical material's behaviour studies. We detail the algorithms of processing developed and optimized to improve the performance of these interferometers especially in terms of time and frequency resolutions. Three methods of analysis of interferometric signals were studied. For Michelson interferometers, the time-frequency analysis of signals by Short-Time Fourier Transform (STFT) is compared to a time-frequency analysis by Continuous Wavelet Transform (CWT). The results have shown that the CWT was more suitable than the STFT for signals with low signal-to-noise, and low velocity and high acceleration areas. For Mach- Zehnder interferometers, the measurement is carried out by analyzing the phase shift between three interferometric signals (Triature processing). These three methods of digital signal processing were evaluated, their measurement uncertainties estimated, and their restrictions or operational limitations specified from experimental results performed on a pulsed power machine. (authors)

  5. Dynamic material properties of refractory metals: tantalum and tantalum/tungsten alloys

    International Nuclear Information System (INIS)

    Furnish, M.D.; Lassila, D.H.; Chhabildas, L.C.; Steinberg, D.J.

    1996-01-01

    We have made a careful set of impact wave-profile measurements (16 profiles) on tantalum and tantalum-tungsten alloys at relatively low stresses (to 15 GPa). Alloys used were Ta 96.5 W 3.5 and Ta 86.5 W 13.5 (wt%) with oxygen contents of 30 endash 70 ppm. Information available from these experiments includes Hugoniot, elastic limits, loading rates, spall strength, unloading paths, reshock structure and specimen thickness effects. Hugoniot and spall properties are illustrated, and are consistent with expectations from earlier work. Modeling the tests with the Steinberg-Guinan-Lund rate-dependent material model provides for an excellent match of the shape of the plastic loading wave. The release wave is not well modeled due to the absence of the dynamic Bauschinger effect. There is also a discrepancy between experiments and calculations regarding the relative timing of the elastic and plastic waves that may be due to texture effects. copyright 1996 American Institute of Physics

  6. Investigation of the dynamic behavior in materials submitted to sub-picosecond laser driven shock

    International Nuclear Information System (INIS)

    Cuq-Lelandais, Jean-Paul

    2010-01-01

    Laser driven shocks allow to investigate materials behavior at high strain rate and present a great interest for research and industrial applications. The latest laser technologies evolutions provide an access to shorter regimes in duration, below the picosecond. This work, which results from a collaboration between the P' institute, the PIMM laboratory and the CEA-DAM, is dedicated to the characterization of the metallic material behavior in this ultra-short mode (aluminium, tantalum), leading to extreme dynamic solicitation in the target (>10 7 s -1 ). The study includes the validation of experimental results obtained on the LULI 100 TW facility by comparison with numerical model. First, the study is orientated to the femtosecond (fs) laser-matter interaction, which is different from what happens in nanosecond regime. Indeed, the characteristic duration scale is comparable to several molecular phenomena like non-equilibrium electrons-ions states. The aim is to determine the equivalent pressure loading induced by the laser pulse on the target. Then, the shock wave propagation within the target has been studied and particularly its pressure decay, notably strong in this regime. In this configuration, the spalls observed are thin, a few μm order, and show a planar rupture morphology. The results obtained by post-mortem observation show that the spall thickness is thinner if the target thickness is reduced. The spalls are characterized by the VISAR measurement. Within the framework of dynamic damage modeling and rupture criteria dimensioning, particularly those which have been validated in the ns regime as Kanel, shots with different thicknesses have been carried out to determine the damage properties in function of strain rate and validate the parameters by prolongation to the ultra-shorts modes. Then, the study has been generalized to the 2D propagation waves, which can explain the spall diameter evolutions. Meanwhile, microscopic simulations of ultra-short laser

  7. Theoretical bases of rotation dynamics of raw materials poller with s ratify consideration for saw gin processing of cotton

    International Nuclear Information System (INIS)

    Saidov, Kh.; Babaeva, A.Kh.

    2005-01-01

    In this paper is examined motion of raw materials rollers on the base of a stratify models. Foe every layers of the rollers are determined dynamical influences for saw gin processing of cotton. It is noticed that in the gin processing of cotton the second layer of cotton roller plagues an important role

  8. Dynamic shock compaction of a ZrO2-RuO2 electronic nanocomposite: toward functionally graded materials

    NARCIS (Netherlands)

    van Zyl, W.E.; Carton, Erik P.; Raming, T.P.; ten Elshof, Johan E.; Verweij, H.

    2005-01-01

    An electronic ZrO2-RuO2 nanocomposite was fabricated by dynamic compaction (DC) at 1.5 GPa resulting in a maximum relative density of 88% in the material. The DC process formed pristine elongated conical-shaped compacts 3 cm in length. The compacts retained their original nanometer-sized grains (~20

  9. Experimental analysis of quasi-static and dynamic fracture initiation toughness of gy4 armor steel material

    Science.gov (United States)

    Ren, Peng; Guo, Zitao

    Quasi-static and dynamic fracture initiation toughness of gy4 armour steel material are investigated using three point bend specimen. The modified split Hopkinson pressure bar (SHPB) apparatus with digital image correlation (DIC) system is applied to dynamic loading experiments. Full-field deformation measurements are obtained by using DIC to elucidate on the strain fields associated with the mechanical response. A series of experiments are conducted at different strain rate ranging from 10-3 s-1 to 103 s-1, and the loading rate on the fracture initiation toughness is investigated. Specially, the scanning electron microscope imaging technique is used to investigate the fracture failure micromechanism of fracture surfaces. The gy4 armour steel material fracture toughness is found to be sensitive to strain rate and higher for dynamic loading as compared to quasi-static loading. This work is supported by National Nature Science Foundation under Grant 51509115.

  10. Materialism.

    Science.gov (United States)

    Melnyk, Andrew

    2012-05-01

    Materialism is nearly universally assumed by cognitive scientists. Intuitively, materialism says that a person's mental states are nothing over and above his or her material states, while dualism denies this. Philosophers have introduced concepts (e.g., realization and supervenience) to assist in formulating the theses of materialism and dualism with more precision, and distinguished among importantly different versions of each view (e.g., eliminative materialism, substance dualism, and emergentism). They have also clarified the logic of arguments that use empirical findings to support materialism. Finally, they have devised various objections to materialism, objections that therefore serve also as arguments for dualism. These objections typically center around two features of mental states that materialism has had trouble in accommodating. The first feature is intentionality, the property of representing, or being about, objects, properties, and states of affairs external to the mental states. The second feature is phenomenal consciousness, the property possessed by many mental states of there being something it is like for the subject of the mental state to be in that mental state. WIREs Cogn Sci 2012, 3:281-292. doi: 10.1002/wcs.1174 For further resources related to this article, please visit the WIREs website. Copyright © 2012 John Wiley & Sons, Ltd.

  11. Influence of frequency of the excitation magnetic field and material's electric conductivity on domain wall dynamics in ferromagnetic materials

    International Nuclear Information System (INIS)

    Chávez-González, A.F.; Pérez-Benítez, J.A.; Espina-Hernández, J.H.; Grössinger, R.; Hallen, J.M.

    2016-01-01

    The present work analyzes the influence of electric conductivity on the Magnetic Barkhausen Noise (MBN) signal using a microscopic model which includes the influence of eddy currents. This model is also implemented to explain the dependence of MBN on the frequency of the applied magnetic field. The results presented in this work allow analyzing the influence of eddy currents on MBN signals for different values of the material's electric conductivity and for different frequencies of applied magnetic field. Additionally, the outcomes of this research can be used as a reference to differentiate the influence of eddy currents from that of second phase particles in the MBN signal, which has been reported in previous works. - Highlights: • Electromagnetic simulation of MBN with eddy currents and micro-magnetism. • Influence of applied field frequency on MBN is explained. • Influence of electric conductivity on MBN is analyzed. • Hysteresis losses in ferromagnetic materials is analyzed using the model.

  12. Bidirectional dynamics of materialism and loneliness : Not just a vicious cycle

    NARCIS (Netherlands)

    Pieters, R.

    2013-01-01

    This research is the first to test the hypothesis that consumers face a “material trap” in which materialism fosters social isolation which in turn reinforces materialism. It provides evidence that materialism and loneliness are engaged in bidirectional relationships over time. Importantly, it finds

  13. Taking the Step towards a More Dynamic View on Raw Material Criticality: An Indicator Based Analysis for Germany and Japan

    Directory of Open Access Journals (Sweden)

    Simon Glöser-Chahoud

    2016-12-01

    Full Text Available Due to mounting concerns about the security of raw material supplies, numerous studies dealing with the quantification of supply risks and material criticality at the national level have been carried out in previous years. Regarding these studies, most approaches are indicator based static screening methods analyzing large numbers of raw materials and identifying those which are most critical for an economy. The majority of these screening methods quantify supply risks and vulnerabilities for one base year without taking into account temporal changes. Dynamic approaches for specific raw materials analyzing affected value chains in detail have been introduced recently; however, these studies do not intend to provide a screening of larger numbers of commodities. In this paper, we present a simple dynamic screening approach to assess raw material criticality at the country level building upon methods from innovation economics. The indicators applied in this study are only based on broadly available production and trade data, which makes this approach relatively easy to apply. We test our methodology on the example of Germany and Japan—two economies with highly specialized industries and low domestic raw material deposits, and, hence, high import dependency. The results are comparable to those of previously conducted multi indicator based static screening methods. However, they provide additional insight into temporal developments over the previous decade.

  14. Development of a sub-scale dynamics model for pressure relaxation of multi-material cells in Lagrangian hydrodynamics

    Directory of Open Access Journals (Sweden)

    Canfield T.R.

    2011-01-01

    Full Text Available We have extended the Sub-Scale Dynamics (SSD closure model for multi-fluid computational cells. Volume exchange between two materials is based on the interface area and a notional interface translation velocity, which is derived from a linearized Riemann solution. We have extended the model to cells with any number of materials, computing pressure-difference-driven volume and energy exchange as the algebraic sum of pairwise interactions. In multiple dimensions, we rely on interface reconstruction to provide interface areas and orientations, and centroids of material polygons. In order to prevent unphysically large or unmanageably small material volumes, we have used a flux-corrected transport (FCT approach to limit the pressure-driven part of the volume exchange. We describe the implementation of this model in two dimensions in the FLAG hydrodynamics code. We also report on Lagrangian test calculations, comparing them with others made using a mixed-zone closure model due to Tipton, and with corresponding calculations made with only single-material cells. We find that in some cases, the SSD model more accurately predicts the state of material in mixed cells. By comparing the algebraic forms of both models, we identify similar dependencies on state and dynamical variables, and propose explanations for the apparent higher fidelity of the SSD model.

  15. Study on dynamic behavior of fusion reactor materials and their response to variable and complex irradiation environment

    International Nuclear Information System (INIS)

    Abe, K.; Kohyama, A.; Namba, C.; Wiffen, F.W.; Jones, R.H.

    2001-01-01

    A Japan-USA Program of irradiation experiments for fusion research, 'JUPITER', has been established as a 6 year program from 1995 to 2000. The goal is to study the dynamic behavior of fusion reactor materials and their response to variable and complex irradiation environment using fission reactors. The irradiation experiments in this program include low activation structural materials, functional ceramics and other innovative materials. The experimental data are analyzed by theoretical modeling and computer simulation to integrate the above effects. The irradiation capsules for in-situ measurement and varying temperature were developed successfully. It was found that insulating ceramics were worked up to 3 dpa. The property changes and related issues in low activation structural materials were summarized. (author)

  16. Materials

    CSIR Research Space (South Africa)

    Van Wyk, Llewellyn V

    2009-02-01

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

  17. Compact acoustic levitation device for studies in fluid dynamics and material science in the laboratory and microgravity

    Science.gov (United States)

    Trinh, E. H.

    1985-01-01

    An ultrasonic levitation device operable in both ordinary ground-based as well as in potential space-borne laboratories is described together with its various applications in the fields of fluid dynamics, material science, and light scattering. Some of the phenomena which can be studied by this instrument include surface waves on freely suspended liquids, the variations of the surface tension with temperature and contamination, the deep undercooling of materials with the temperature variations of their density and viscosity, and finally some of the optical diffraction properties of transparent substances.

  18. X-ray Studies of Materials Dynamics at MHATT-CAT Sector 7 , Advanced Photon Source. Final report

    International Nuclear Information System (INIS)

    Roy Clarke

    2006-01-01

    This Final Report describes the scientific accomplishments that have been achieved with support from grant DE-FG02-03ER46023 during the period 12/01/02-11/30/05. The funding supported a vigorous scientific program allowing the PI to achieve leadership in a number of important areas. In particular, research carried out during this period has opened way to ultrafast dynamics studies of materials by combining the capabilities of synchrotron radiation with those of ultrafast lasers. This enables the initiation of laser-induced excitations and studies of their subsequent dynamics using laser-pump/x-ray probe techniques. Examples of such excitations include phonons, shock waves, excitons, spin-waves, and polaritons. The breadth of phenomena that can now be studied in the time-domain is very broad, revealing new phenomena and mechanisms that are critical to many applications of materials

  19. Revealing the ultrafast charge carrier dynamics in organo metal halide perovskite solar cell materials using time resolved THz spectroscopy

    Science.gov (United States)

    Ponseca, C. S., Jr.; Sundström, V.

    2016-03-01

    Ultrafast charge carrier dynamics in organo metal halide perovskite has been probed using time resolved terahertz (THz) spectroscopy (TRTS). Current literature on its early time characteristics is unanimous: sub-ps charge carrier generation, highly mobile charges and very slow recombination rationalizing the exceptionally high power conversion efficiency for a solution processed solar cell material. Electron injection from MAPbI3 to nanoparticles (NP) of TiO2 is found to be sub-ps while Al2O3 NPs do not alter charge dynamics. Charge transfer to organic electrodes, Spiro-OMeTAD and PCBM, is sub-ps and few hundreds of ps respectively, which is influenced by the alignment of energy bands. It is surmised that minimizing defects/trap states is key in optimizing charge carrier extraction from these materials.

  20. Optimization of vibration amplitudes of the dynamic rotors by introducing hysteresis parameters of materials

    Energy Technology Data Exchange (ETDEWEB)

    Kamel, Lebchek; Outtas, T. [Laboratory of Structural Mechanics and Materials faculty of technology - University of Batna, Batha (Algeria)

    2013-07-01

    The aim of this work is the study of behavior of rotor dynamics of industrial turbines, using numerical simulation. Finite element model was developed by introducing a new hysteresis parameter to control more precisely the behavior of rolling bearings. The finite element model is used to extract the natural frequencies and modal deformed rotor vibration, as it identifies the constraints acting on the system and predict the dynamic behavior of the rotor transient. Results in Campbell diagram and those relating to the unbalance responses show significant amplitude differences in the parameters of hysteresis imposed . Key words: rotor dynamics, hysteresis, finite element, rotor vibration, unbalance responses, Campbell diagram.

  1. Integrated Reacting Fluid Dynamics and Predictive Materials Degradation Models for Propulsion System Conditions, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Computational fluid dynamics (CFD) simulations are routinely used by NASA to optimize the design of propulsion systems. Current methods for CFD modeling rely on...

  2. Nonlinear dynamic analysis and state space representation of a manipulator under viscoelastic material conditions

    Directory of Open Access Journals (Sweden)

    Esfandiar, H.

    2013-05-01

    Full Text Available In this paper, based on the VoigtKelvin constitutive model, nonlinear dynamic modelling and state space representation of a viscoelastic beam acting as a flexible robotic manipulator is investigated. Complete nonlinear dynamic modelling of a viscoelastic beam without premature linearisation of dynamic equations is developed. The adopted method is capable of reproducing nonlinear dynamic effects, such as beam stiffening due to centrifugal and Coriolis forces induced by rotation of the joints. Structural damping effects on the models dynamic behaviour are also shown. A reliable model for a viscoelastic beam is subsequently presented. The governing equations of motion are derived using Hamiltons principle, and using the finite difference method, nonlinear partial differential equations are reduced to ordinary differential equations. For the purpose of flexible manipulator control, the standard form of state space equations for the viscoelastic link and the actuator is obtained. Simulation results indicate substantial improvements in dynamic behaviour, and a parameter sensitivity study is carried out to investigate the effect of structural damping on the vibration amplitude.

  3. DEVELOPMENT SCIENTIFIC INQUIRY BASED TEACHING MATERIALS ON DYNAMIC FLUIDS TO IMPROVE STUDENTS ACHIEVEMENT

    Directory of Open Access Journals (Sweden)

    Jeliana Veronika Sirait

    2016-06-01

    Full Text Available The study was conducted to investigate whether the developed scientific inquiry-based teaching materials can improve the students’ response, the students’ activity and the students’ achievement. This study is development which based on Borg & Gall product development. Samples were selected randomly by raffling 4 classes into one class, applied teaching materials based scientific inquiry. The instruments which are used in this study consisted of three namely quetionnaires used for validation of teaching material by the expert of the material and the expert of design, the evaluation of physics teacher and students’ response toward teaching materials and observation sheet of students’ activity used in learning process and also test for students’ achievement in the form of multiple choice consisted of 10 quetions provided for end of the learning. The results of this study showed that the developed scientific inquiry-based teaching materials can improve the students’ response, the students’ activity and the students’ achievement in every session.

  4. Comparison of the dynamic behaviour of brain tissue and two model materials

    NARCIS (Netherlands)

    Brands, D.W.A.; Bovendeerd, P.H.M.; Peters, G.W.M.; Wismans, J.S.H.M.; Paas, M.H.J.W.; Bree, van J.L.M.J.; Brands, D.W.A.

    1999-01-01

    Linear viscoelastic material parameters of porcine brain tissue and two brain substitute/ materials for use in mechanical head models (edible bone gelatin and dielectric silicone gel) were determined in small deformation, oscillatory shear experiments. Frequencies to 1000 Hertz could be obtained

  5. Dynamic material characterization by combining ballistic testing and an engineering model

    NARCIS (Netherlands)

    Carton, E.P.; Roebroeks, G.H.J.J.; Wal, R. van der

    2013-01-01

    At TNO several energy-based engineering models have been created for various failure mechanism occurring in ballistic testing of materials, like ductile hole growth, denting, plugging, etc. Such models are also under development for ceramic and fiberbased materials (fabrics). As the models are

  6. Material density measurements from dynamic flash x-ray radiographs using axisymmetric tomography

    International Nuclear Information System (INIS)

    Fugelso, E.

    1981-03-01

    The axisymmetric version of the tomographic x-ray reconstruction procedures has been utilized to determine the material density for the impact of a cylinder on a steel plate. Derivations of the reconstruction algorithms relating x-ray radiographic intensities to the material densities are presented. Effects of noise, point spread functions, and motion blur are minimized

  7. Prediction of serviceability of the material working under conditions of dynamic contact with liquid medium

    International Nuclear Information System (INIS)

    Veksler, Yu.G.; Poluyanov, V.B.

    1977-01-01

    A method is suggested for selecting materials working in contact with fusible liquid metals under namic loading. It is recommended to determine the rate of failure in short-time tests of materials which have shown good corrosion resistence. A material thus selected is subject to short-time cavitation mechanical strength test and a creep test. After that the cavitation-mechanical strength is to be calculated with an account for variation of transverse cross-section area. An equation of cavitation failure rate vs. time is given

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

    KAUST Repository

    Shaheen, Basamat; Sun, Jingya; Yang, Ding-Shyue; Mohammed, Omar F.

    2017-01-01

    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

  9. Porous alkali activated materials with slow alkali release dynamic. Role of composition

    International Nuclear Information System (INIS)

    Bumanis, G.; Bajare, D.

    2018-01-01

    Alkali activated materials (AAM) based on calcined metakaolin or illite clay together with waste by-products, such as waste glass or aluminium scrap recycling waste, were tested as value-added materials for pH stabilization in biogas technology where decrease of pH should be avoided. Porous materials with ability to slowly leach alkalis in the water media thus providing continuous control of the pH level were obtained. XRD, FTIR, SEM and titration methods were used to characterize AAM and their leaching properties. It is clear that composition of the material has an important effect on the diffusion of alkali from structure. Namely, higher Si/Al and Na/Al molar ratios may increase pore solution transfer to the leachate. The leaching rate of alkalis from the structure of AAM is high for the first few days, decreasing over time. It was possible to calculate the buffer capacity from the mixture design of AAM. [es

  10. Reversible and Irreversible Behavior of Glass-forming Materials from the Standpoint of Hierarchical Dynamical Facilitation

    Science.gov (United States)

    Keys, Aaron

    2013-03-01

    Using molecular simulation and coarse-grained lattice models, we study the dynamics of glass-forming liquids above and below the glass transition temperature. In the supercooled regime, we study the structure, statistics, and dynamics of excitations responsible for structural relaxation for several atomistic models of glass-formers. Excitations (or soft spots) are detected in terms of persistent particle displacements. At supercooled conditions, we find that excitations are associated with correlated particle motions that are sparse and localized, and the statistics and dynamics of these excitations are facilitated and hierarchical. Excitations at one point in space facilitate the birth and death of excitations at neighboring locations, and space-time excitation structures are microcosms of heterogeneous dynamics at larger scales. Excitation-energy scales grow logarithmically with the characteristic size of the excitation, giving structural-relaxation times that can be predicted quantitatively from dynamics at short time scales. We demonstrate that these same physical principles govern the dynamics of glass-forming systems driven out-of-equilibrium by time-dependent protocols. For a system cooled and re-heated through the glass transition, non-equilibrium response functions, such as heat capacities, are notably asymmetric in time, and the response to melting a glass depends markedly on the cooling protocol by which the glass was formed. We introduce a quantitative description of this behavior based on the East model, with parameters determined from reversible transport data, that agrees well with irreversible differential scanning calorimetry. We find that the observed hysteresis and asymmetric response is a signature of an underlying dynamical transition between equilibrium melts with no trivial spatial correlations and non-equilibrium glasses with correlation lengths that are both large and dependent upon the rate at which the glass is prepared. The correlation

  11. Experimental studies on the performance of novel layered materials under highly dynamic loads

    Energy Technology Data Exchange (ETDEWEB)

    Shukla, A, E-mail: shuklaa@egr.uri.ed [Dynamic Photomechanics Laboratory Department of Mechanical Engineering and Applied Mechanics University of Rhode Island, Kingston, RI 02881 (United States)

    2009-08-01

    This paper focuses on the experimental observations of the performance of different layered composite material systems subjected to blast loadings. These material systems include layered composites and sandwich composite materials. A controlled blast loading of pre-defined pressure magnitude and rise time were obtained using a shock tube apparatus. Rectangular plate elements of the desired material system were subjected to such a controlled blast loading and the effects of the blast loading on these elements were studied using optical and residual strength measurements. A high speed imaging technique was utilized to study the damage modes and mechanisms in real time. It was observed that layering of a conventional composite material with a soft visco-elastic polymer provided better blast resistance and sandwiching the polymer greatly enhanced its survivability under extreme air blast conditions. Aside from layering the conventional composite material with a soft visco-elastic polymer, it was observed that layering or grading the core can successfully mitigate the impact damage and thus improve the overall blast resistance as well. In addition to these, three dimensional (3D) woven skin and core reinforcements were introduced in the conventional sandwich composites and their effects on the blast resistance were studied experimentally. It was observed that these reinforcements also enhance the blast resistance of conventional sandwich composites by changing the mechanism of failure initiation and propagation in these sandwich structures.

  12. Presence of IgE cells in human placenta is independent of malaria infection or chorioamnionitis

    DEFF Research Database (Denmark)

    Rindsjö, E; Hulthén Varli, I; Ofori, M F

    2006-01-01

    We have shown previously that numerous IgE(+) macrophage-like cells are present in the villous stroma of full term placenta and that there was no difference in the amount of IgE(+) cells between allergic and non-allergic mothers. The presence of such an abundant number of IgE(+) cells...... from Ghana with and without malaria parasites. The immunohistochemical staining pattern for IgE looked similar to our previous study, with the IgE located on Hofbauer-like cells. We could not find any difference in the amount or distribution of IgE(+) cells between malaria-infected and non...

  13. X-ray imaging of subsurface dynamics in high-Z materials at the Diamond Light Source

    Science.gov (United States)

    Eakins, D. E.; Chapman, D. J.

    2014-12-01

    In this paper, we describe a new approach enabling study of subsurface dynamics in high-Z materials using the unique combination of high-energy synchrotron X-rays, a hybrid bunch structure, and a new dynamic loading platform. We detail the design and operation of the purpose-built, portable small bore gas-gun, which was installed on the I12 high-energy beamline at the Diamond Light Source and used to drive compression waves into solid and porous metal targets. Using a hybrid bunch structure and broadband X-ray pulses of up to 300 keV, radiographic snapshots were captured during various dynamic deformation processes in cm-scale specimens, thereby contributing to a more complete understanding of the evolution of mesoscale damage. Importantly, we highlight strategies for overcoming the challenges associated with using high-energy X-rays, and suggest areas for improvement needed to advance dynamic imaging through large-scale samples of relevance to engineering scenarios. These preliminary measurements demonstrate the feasibility of probing highly transient phenomena using the presented methodology.

  14. X-ray imaging of subsurface dynamics in high-Z materials at the Diamond Light Source

    International Nuclear Information System (INIS)

    Eakins, D. E.; Chapman, D. J.

    2014-01-01

    In this paper, we describe a new approach enabling study of subsurface dynamics in high-Z materials using the unique combination of high-energy synchrotron X-rays, a hybrid bunch structure, and a new dynamic loading platform. We detail the design and operation of the purpose-built, portable small bore gas-gun, which was installed on the I12 high-energy beamline at the Diamond Light Source and used to drive compression waves into solid and porous metal targets. Using a hybrid bunch structure and broadband X-ray pulses of up to 300 keV, radiographic snapshots were captured during various dynamic deformation processes in cm-scale specimens, thereby contributing to a more complete understanding of the evolution of mesoscale damage. Importantly, we highlight strategies for overcoming the challenges associated with using high-energy X-rays, and suggest areas for improvement needed to advance dynamic imaging through large-scale samples of relevance to engineering scenarios. These preliminary measurements demonstrate the feasibility of probing highly transient phenomena using the presented methodology

  15. Translational and rotational dynamics of water in mesoporous silica materials: MCM-41-S and MCM-48-S

    International Nuclear Information System (INIS)

    Faraone, Antonio; Liu Li; Mou, C.-Y.; Shih, P.-C.; Copley, John R.D.; Chen, S.-H.

    2003-01-01

    We investigated the translational and rotational dynamics of water molecules in mesoporous silica materials MCM-41-S and MCM-48-S using the incoherent quasielastic neutron scattering technique. The range of wave vector transfers Q covered in the measurements was from 0.27 to 1.93 Aa -1 broad enough to detect both the translational and rotational contributions to the scattering. We used the relaxing-cage models for both translational and rotational motions which we developed earlier, to analyze the QENS spectra and investigated water dynamics in a supercooled range from 250 to 280 K. The results show a marked slowing down of both the translational and rotational relaxation times, and an increasing effect of confinement on the translational motion, as the temperature is lowered

  16. Elastic, Frictional, Strength and Dynamic Characteristics of the Bell Shape Shock Absorbers Made of MR Wire Material

    Science.gov (United States)

    Lazutkin, G. V.; Davydov, D. P.; Boyarov, K. V.; Volkova, T. V.

    2018-01-01

    The results of the mechanical characteristic experimental studies are presented for the shock absorbers of DKU type with the elastic elements of the bell shape made of MR material and obtained by the cold pressing of mutually crossing wire spirals with their inclusion in the array of reinforcing wire harnesses. The design analysis and the technology of MR production based on the methods of similarity theory and dimensional analysis revealed the dimensionless determined and determining parameters of elastic frictional, dynamic and strength characteristics under the static and dynamic loading of vibration isolators. The main similarity criteria of mechanical characteristics for vibration isolators and their graphical and analytical representation are determined, taking into account the coefficients of these (affine) transformations of the hysteresis loop family field.

  17. The analysis of the mathematics concept comprehension of senior high school student on dynamic fluid material

    Science.gov (United States)

    Kristian, P. L. Y.; Cari, C.; Sunarno, W.

    2018-04-01

    This study purposes to describe and analyse the students' concept understanding of dynamic fluid. The subjects of this research are 10 students of senior high school. The data collected finished the essay test that consists of 5 questions have been adapted to the indicators of learning. The data of this research is analysed using descriptive-qualitative approach by referring of the student's argumentations about their answer from the questions that given. The results showed that students still have incorrect understanding the concept of dynamic fluids, especially on the Bernoulli’s principle and its application. Based on the results of this research, the teachers should emphasize the concept understanding of the students therefore the students don not only understand the physics concept in mathematical form.

  18. Applying Constructionism and Problem Based Learning for Developing Dynamic Educational Material for Mathematics At Undergraduate University Level

    DEFF Research Database (Denmark)

    Triantafyllou, Eva; Timcenko, Olga

    2013-01-01

    As a result of changes in society and education, assumptions about the knowledge of entrants to university have become obsolete. One area in which this seems to be true is mathematics. This paper presents our research aiming at tackling with this problem by developing digital educational material...... for mathematics education, which will be student-driven, dynamic, and multimodal. Our approach will be supported by the theories of Constructionism and PBL. The impact of its use will be evaluated in university settings. It is expected that the evaluation will demonstrate an improvement in student engagement...

  19. Application of the basic concepts of dynamic materials accountancy to the Tokai spent fuel reprocessing facilityssing facility

    International Nuclear Information System (INIS)

    Lovett, J.E.; Ikawa, Koji; Hirata, Mitsuho; Augustson, R.H.

    1980-11-01

    During 1978 and 1979 individuals from the International Atomic Energy Agency, the Los Alamos Scientific Laboratory, and the Japan Atomic Energy Research Institute investigated the feasibility of applying the basic concepts of dynamic materials accountancy to PNC-Tokai reprocessing facility in Japan. The system developed for Tokai requires weekly in-process physical inventories for the process MBA, and allows 2-3 additional days for completion of measurements and for data reduction and evaluation. The study concluded that such a system would be feasible, and recommended that an actual field test should be conducted as soon as feasible. (author)

  20. A study on the evaluation for dynamic fracture mechanics parameters of viscoelastic materials by impact bending

    International Nuclear Information System (INIS)

    Sim, Jae Ki; Cho, Kyu Jac

    1988-01-01

    In this paper We derived simple formulas for the dynamic strain intensity factor by means of the Timoshenko's beam theory including the influence of rotary inertia and shear deformation on the three-point viscoelastic bend specimen. Also the contact force between the specimen and the impactor is estimated by appling the nonlinear integral equation and the Hertz's theory to the local deformation near the contact point. The results obtained from this study are as follow : 1. Analysis results of this paper, base on Timoshenko's beam theory, were more accuracy than that of Euler-Bernouli beam theory and it can be confirmed by comparsion the results with experimental results. 2. Hertz's contact thepry is static one, but it is proved that by the solution of dynamic strain intensity factor it can be applied for the case of dynamic one. 3. It is founded that the fracture mechanics paraments are overestimatimated if the effects of rotary inertia and transverse shear deformation of specimen are negleted. (Author)

  1. Dynamics of the rupture precursors for heterogeneous materials: application to vitreous polymers foams

    International Nuclear Information System (INIS)

    Deschanel, St.

    2005-12-01

    New physical approaches concerning the damage mechanisms consist to consider the rupture phenomenon as the critical point of a phase transition. Rupture can then result for some materials by a percolation of microcracks. This multi-crack implies the choice of heterogeneous materials. Mechanical tests on solid polymer foams have been carried out until rupture and have been coupled to the follow-up of the acoustic activity. The energies distributions reveal power laws independently of the material density, of the load mode or of the behaviour laws. On the other hand, the agreement with a power law of time periods seems to require a quasi constant stress on the most part of the test. The trend of the cumulated energy in the case of creep experiments seems to present a power law on a narrow period of time. On the other hand, for tensile tests, no power law has been observed. (O.M.)

  2. Characterization of dynamic material properties of light alloys for crashworthiness applications

    Directory of Open Access Journals (Sweden)

    Nuno Peixinho

    2010-12-01

    Full Text Available This paper presents results on the tensile testing of AZ31B-H24 magnesium alloy and 6111-T4 aluminium alloy at different strain rates. These materials are strong candidates for use in crashworthy automotive components and parts due to their well-balanced combination of strength, stiffness and density. To test their application in the auto industry an understanding of material behaviour at relevant strain rates is needed, as well as constitutive equations suitable for use in analytical and numerical calculations. Mechanical properties were determined from tensile tests using flat sheet samples, employing two different test techniques: a servo-hydraulic machine and a tensile-loading Hopkinson bar. The test results were used to compare different mechanical properties of the tested materials and to validate constitutive equations intended to provide a mathematical description of strain rate dependence. The Cowper-Symonds equation was examined.

  3. Topology optimization of periodic microstructures for enhanced dynamic properties of viscoelastic composite materials

    DEFF Research Database (Denmark)

    Andreassen, Erik; Jensen, Jakob Søndergaard

    2014-01-01

    We present a topology optimization method for the design of periodic composites with dissipative materials for maximizing the loss/attenuation of propagating waves. The computational model is based on a finite element discretization of the periodic unit cell and a complex eigenvalue problem...... with a prescribed wave frequency. The attenuation in the material is described by its complex wavenumber, and we demonstrate in several examples optimized distributions of a stiff low loss and a soft lossy material in order to maximize the attenuation. In the examples we cover different frequency ranges and relate...... the results to previous studies on composites with high damping and stiffness based on quasi-static conditions for low frequencies and the bandgap phenomenon for high frequencies. Additionally, we consider the issues of stiffness and connectivity constraints and finally present optimized composites...

  4. Equivalent material properties of perforated plate with triangular or square penetration pattern for dynamic analysis

    International Nuclear Information System (INIS)

    Jhung, Myung Jo; Jo, Jong Chull

    2006-01-01

    For a perforated plate, it is challenging to develop a finite element model due to the necessity of the fine meshing of the plate, especially if it is submerged in fluid. This necessitates the use of a solid plate with equivalent material properties. Unfortunately, the effective elastic constants suggested by the ASME code are deemed not valid for a model analysis. Therefore, in this study the equivalent material properties of a perforated plate are suggested by performing several finite element analyses with respect to the ligament efficiencies

  5. Dynamic Use of Digital Library Material - Supporting Users with Typed Links in Open Hypermedia

    DEFF Research Database (Denmark)

    Grønbæk, Kaj; Hansen, Klaus Marius; Yndigegn, Christian

    1999-01-01

    This paper introduces a novel approach to supporting digital library users in organising and annotating material. We have extended the concept of open hypermedia by introducing typed links, which support: addition of (user-defined) semantics to hypertexts, user navigation, and machine supported...... analysis and synthesis of hypermedia structures. The Webvise open hypermedia system is integrated with the World Wide Web, and has been augmented with a type system. We illustrate the potential use in the context of digital libraries with a scenario of teachers jointly preparing a course based on digital...... library material....

  6. Dynamic Data Driven Experiment Control Coordinated with Anisotropic Elastic Material Characterization

    Science.gov (United States)

    John G. Michopoulos; Tomonari Furukawa; John C. Hermanson; Samuel G. Lambrakos

    2011-01-01

    The goal of this paper is to propose and demonstrate a multi level design optimization approach for the coordinated determination of a material constitutive model synchronously to the design of the experimental procedure needed to acquire the necessary data. The methodology achieves both online (real-time) and offline design of optimum experiments required for...

  7. Hysteresis in magnetic materials: the role of structural disorder, thermal relaxation, and dynamic effects

    International Nuclear Information System (INIS)

    Bertotti, G.; Basso, V.; Beatrice, C.; LoBue, M.; Magni, A.; Tiberto, P.

    2001-01-01

    An overview is given of the present understanding of hysteresis phenomena in magnetic materials. The problem is addressed from three approximate viewpoints: the connection between rate-independent hysteresis and micromagnetics; the modifications brought into this picture by thermal relaxation effects; the role of rate-dependent magnetization mechanisms, like eddy-current-damped domain wall motion

  8. Probing the Dynamics of Ultra-Fast Condensed State Reactions in Energetic Materials

    Science.gov (United States)

    Piekiel, Nicholas William

    2012-01-01

    Energetic materials (EMs) are substances with a high amount of stored energy and the ability to release that energy at a rapid rate. Nanothermites and green organic energetics are two classes of EMs which have gained significant interest as they each have desirable properties over traditional explosives. These systems also possess downfalls, which…

  9. A study of microbial population dynamics associated with corrosion rates influenced by corrosion control materials

    NARCIS (Netherlands)

    Chang, Yu Jie; Hung, Chun Hsiung; Lee, Jyh Wei; Chang, Yi Tang; Lin, Fen Yu; Chuang, Chun Jie

    2015-01-01

    This research aims to analyze the variations of microbial community structure under anaerobic corrosive conditions, using molecular fingerprinting method. The effect of adding various materials to the environment on the corrosion mechanism has been discussed. In the initial experiment,

  10. The mechanical properties modeling of nano-scale materials by molecular dynamics

    NARCIS (Netherlands)

    Yuan, C.; Driel, W.D. van; Poelma, R.; Zhang, G.Q.

    2012-01-01

    We propose a molecular modeling strategy which is capable of mod-eling the mechanical properties on nano-scale low-dielectric (low-k) materials. Such modeling strategy has been also validated by the bulking force of carbon nano tube (CNT). This modeling framework consists of model generation method,

  11. Dynamic behaviour of interphases and its implication on high-energy-density cathode materials in lithium-ion batteries

    Science.gov (United States)

    Li, Wangda; Dolocan, Andrei; Oh, Pilgun; Celio, Hugo; Park, Suhyeon; Cho, Jaephil; Manthiram, Arumugam

    2017-01-01

    Undesired electrode–electrolyte interactions prevent the use of many high-energy-density cathode materials in practical lithium-ion batteries. Efforts to address their limited service life have predominantly focused on the active electrode materials and electrolytes. Here an advanced three-dimensional chemical and imaging analysis on a model material, the nickel-rich layered lithium transition-metal oxide, reveals the dynamic behaviour of cathode interphases driven by conductive carbon additives (carbon black) in a common nonaqueous electrolyte. Region-of-interest sensitive secondary-ion mass spectrometry shows that a cathode-electrolyte interphase, initially formed on carbon black with no electrochemical bias applied, readily passivates the cathode particles through mutual exchange of surface species. By tuning the interphase thickness, we demonstrate its robustness in suppressing the deterioration of the electrode/electrolyte interface during high-voltage cell operation. Our results provide insights on the formation and evolution of cathode interphases, facilitating development of in situ surface protection on high-energy-density cathode materials in lithium-based batteries. PMID:28443608

  12. Comparison of one-dimensional probabilistic finite element method with direct numerical simulation of dynamically loaded heterogeneous materials

    Science.gov (United States)

    Robbins, Joshua; Voth, Thomas

    2011-06-01

    Material response to dynamic loading is often dominated by microstructure such as grain topology, porosity, inclusions, and defects; however, many models rely on assumptions of homogeneity. We use the probabilistic finite element method (WK Liu, IJNME, 1986) to introduce local uncertainty to account for material heterogeneity. The PFEM uses statistical information about the local material response (i.e., its expectation, coefficient of variation, and autocorrelation) drawn from knowledge of the microstructure, single crystal behavior, and direct numerical simulation (DNS) to determine the expectation and covariance of the system response (velocity, strain, stress, etc). This approach is compared to resolved grain-scale simulations of the equivalent system. The microstructures used for the DNS are produced using Monte Carlo simulations of grain growth, and a sufficient number of realizations are computed to ensure a meaningful comparison. Finally, comments are made regarding the suitability of one-dimensional PFEM for modeling material heterogeneity. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  13. Assessment of the gas dynamic trap mirror facility as intense neutron source for fusion material test irradiations

    International Nuclear Information System (INIS)

    Fischer, U.; Moeslang, A.; Ivanov, A.A.

    2000-01-01

    The gas dynamic trap (GDT) mirror machine has been proposed by the Budker Institute of nuclear physics, Novosibirsk, as a volumetric neutron source for fusion material test irradiations. On the basis of the GDT plasma confinement concept, 14 MeV neutrons are generated at high production rates in the two end sections of the axially symmetrical central mirror cell, serving as suitable irradiation test regions. In this paper, we present an assessment of the GDT as intense neutron source for fusion material test irradiations. This includes comparisons to irradiation conditions in fusion reactor systems (ITER, Demo) and the International Fusion Material Irradiation Facility (IFMIF), as well as a conceptual design for a helium-cooled tubular test assembly elaborated for the largest of the two test zones taking proper account of neutronics, thermal-hydraulic and mechanical aspects. This tubular test assembly incorporates ten rigs of about 200 cm length used for inserting instrumented test capsules with miniaturized specimens taking advantage of the 'small specimen test technology'. The proposed design allows individual temperatures in each of the rigs, and active heating systems inside the capsules ensures specimen temperature stability even during beam-off periods. The major concern is about the maximum achievable dpa accumulation of less than 15 dpa per full power year on the basis of the present design parameters of the GDT neutron source. A design upgrading is proposed to allow for higher neutron wall loadings in the material test regions

  14. Material properties for reactor pressure vessels and containment shells under dynamic loading

    International Nuclear Information System (INIS)

    Albertini, C.

    1997-01-01

    The effects of high strain rate, dynamic biaxial loading and deformation mode (tension, shear) on the mechanical properties of AISI 316 austenitic stainless steel in as-received and pre-damaged (creep, LCF) conditions are reported. This research was conducted to assess the performances of the containment shell of fast breeder reactors. The results of this research have been utilized to prepare similar investigations for SA 537 Class 1 ferritic steel used for the containment shell of LWR. The first results of these investigations are reported. A programme to study the mechanical properties of plain concrete with real size aggregate at high strain rate is described. (orig.)

  15. Atomic-scale processes revealing dynamic twin boundary strengthening mechanisms in face-centered cubic materials

    International Nuclear Information System (INIS)

    Yang, Z.Q.; Chisholm, M.F.; He, L.L.; Pennycook, S.J.; Ye, H.Q.

    2012-01-01

    We report experimental investigations on interactions/reactions between dislocations and twin boundaries in Al. The absorption of screw dislocations via cross-slip and the production of stair-rods via reactions with non-screw dislocations were verified by atomic resolution imaging. Importantly, the resulting partial dislocations moving along twin boundaries can produce secondary sessile defects. These immobile defects act as obstacles to other dislocations and also serve to pin the twin boundaries. These findings show the atomic-level dynamics of the dislocation–twin boundary processes and the unique strengthening mechanism of twin boundaries in face-centered cubic metals.

  16. Self-consistent nonlinearly polarizable shell-model dynamics for ferroelectric materials

    International Nuclear Information System (INIS)

    Mkam Tchouobiap, S.E.; Kofane, T.C.; Ngabireng, C.M.

    2002-11-01

    We investigate the dynamical properties of the polarizable shellmodel with a symmetric double Morse-type electron-ion interaction in one ionic species. A variational calculation based on the Self-Consistent Einstein Model (SCEM) shows that a theoretical ferroelectric (FE) transition temperature can be derive which demonstrates the presence of a first-order phase transition for the potassium selenate (K 2 SeO 4 ) crystal around Tc 91.5 K. Comparison of the model calculation with the experimental critical temperature yields satisfactory agreement. (author)

  17. Near infrared spectroscopy based monitoring of extraction processes of raw material with the help of dynamic predictive modeling

    Science.gov (United States)

    Wang, Haixia; Suo, Tongchuan; Wu, Xiaolin; Zhang, Yue; Wang, Chunhua; Yu, Heshui; Li, Zheng

    2018-03-01

    The control of batch-to-batch quality variations remains a challenging task for pharmaceutical industries, e.g., traditional Chinese medicine (TCM) manufacturing. One difficult problem is to produce pharmaceutical products with consistent quality from raw material of large quality variations. In this paper, an integrated methodology combining the near infrared spectroscopy (NIRS) and dynamic predictive modeling is developed for the monitoring and control of the batch extraction process of licorice. With the spectra data in hand, the initial state of the process is firstly estimated with a state-space model to construct a process monitoring strategy for the early detection of variations induced by the initial process inputs such as raw materials. Secondly, the quality property of the end product is predicted at the mid-course during the extraction process with a partial least squares (PLS) model. The batch-end-time (BET) is then adjusted accordingly to minimize the quality variations. In conclusion, our study shows that with the help of the dynamic predictive modeling, NIRS can offer the past and future information of the process, which enables more accurate monitoring and control of process performance and product quality.

  18. Dynamic induced softening in frictional granular materials investigated by discrete-element-method simulation

    Science.gov (United States)

    Lemrich, Laure; Carmeliet, Jan; Johnson, Paul A.; Guyer, Robert; Jia, Xiaoping

    2017-12-01

    A granular system composed of frictional glass beads is simulated using the discrete element method. The intergrain forces are based on the Hertz contact law in the normal direction with frictional tangential force. The damping due to collision is also accounted for. Systems are loaded at various stresses and their quasistatic elastic moduli are characterized. Each system is subjected to an extensive dynamic testing protocol by measuring the resonant response to a broad range of ac drive amplitudes and frequencies via a set of diagnostic strains. The system, linear at small ac drive amplitudes, has resonance frequencies that shift downward (i.e., modulus softening) with increased ac drive amplitude. Detailed testing shows that the slipping contact ratio does not contribute significantly to this dynamic modulus softening, but the coordination number is strongly correlated to this reduction. This suggests that the softening arises from the extended structural change via break and remake of contacts during the rearrangement of bead positions driven by the ac amplitude.

  19. Image processing pipeline for segmentation and material classification based on multispectral high dynamic range polarimetric images.

    Science.gov (United States)

    Martínez-Domingo, Miguel Ángel; Valero, Eva M; Hernández-Andrés, Javier; Tominaga, Shoji; Horiuchi, Takahiko; Hirai, Keita

    2017-11-27

    We propose a method for the capture of high dynamic range (HDR), multispectral (MS), polarimetric (Pol) images of indoor scenes using a liquid crystal tunable filter (LCTF). We have included the adaptive exposure estimation (AEE) method to fully automatize the capturing process. We also propose a pre-processing method which can be applied for the registration of HDR images after they are already built as the result of combining different low dynamic range (LDR) images. This method is applied to ensure a correct alignment of the different polarization HDR images for each spectral band. We have focused our efforts in two main applications: object segmentation and classification into metal and dielectric classes. We have simplified the segmentation using mean shift combined with cluster averaging and region merging techniques. We compare the performance of our segmentation with that of Ncut and Watershed methods. For the classification task, we propose to use information not only in the highlight regions but also in their surrounding area, extracted from the degree of linear polarization (DoLP) maps. We present experimental results which proof that the proposed image processing pipeline outperforms previous techniques developed specifically for MSHDRPol image cubes.

  20. Dynamic diagnostics of moving ferromagnetic material with the linear induction motor

    Directory of Open Access Journals (Sweden)

    Szewczyk Krzysztof

    2017-01-01

    Full Text Available The paper presents the application of a three-phase induction motor as a sensor measuring the force of the electromagnetic field connection between the engine and produced sheet steel. The force interaction between the engine and the manufactured sheet metal treated as a treadmill for a linear motor may be an indicator of damage to the material. Detection of places where the sheet does not meet the quality requirements may be very useful in the production process. FEM calculations were performed in the ANSYS MAXWELL environment. The results suggest the possibility of using this type of construction to test the quality of produced materials. The computational results and their analysis are presented in this article.

  1. Determination of the dynamical behaviour of biological materials during impact using a pendulum device

    Science.gov (United States)

    Van Zeebroeck, M.; Tijskens, E.; Van Liedekerke, P.; Deli, V.; De Baerdemaeker, J.; Ramon, H.

    2003-09-01

    A pendulum device has been developed to measure contact force, displacement and displacement rate of an impactor during its impact on the sample. Displacement, classically measured by double integration of an accelerometer, was determined in an alternative way using a more accurate incremental optical encoder. The parameters of the Kuwabara-Kono contact force model for impact of spheres have been estimated using an optimization method, taking the experimentally measured displacement, displacement rate and contact force into account. The accuracy of the method was verified using a rubber ball. Contact force parameters for the Kuwabara-Kono model have been estimated with success for three biological materials, i.e., apples, tomatoes and potatoes. The variability in the parameter estimations for the biological materials was quite high and can be explained by geometric differences (radius of curvature) and by biological variation of mechanical tissue properties.

  2. Negotiating energy dynamics through embodied action in a materially structured environment

    Directory of Open Access Journals (Sweden)

    Rachel E. Scherr

    2013-07-01

    Full Text Available We provide evidence that a learning activity called Energy Theater engages learners with key conceptual issues in the learning of energy, including disambiguating matter flow and energy flow and theorizing mechanisms for energy transformation. A participationist theory of learning, in which learning is indicated by changes in speech and behavior, supports ethnographic analysis of learners’ embodied interactions with each other and the material setting. We conduct detailed analysis to build plausible causal links between specific features of Energy Theater and the conceptual engagement that we observe. Disambiguation of matter and energy appears to be promoted especially by the material structure of the Energy Theater environment, in which energy is represented by participants, while objects are represented by areas demarcated by loops of rope. Theorizing mechanisms of energy transformation is promoted especially by Energy Theater’s embodied action, which necessitates modeling the time ordering of energy transformations.

  3. Dynamic diagnostics of moving ferromagnetic material with the linear induction motor

    OpenAIRE

    Szewczyk Krzysztof; Walasek Tomasz

    2017-01-01

    The paper presents the application of a three-phase induction motor as a sensor measuring the force of the electromagnetic field connection between the engine and produced sheet steel. The force interaction between the engine and the manufactured sheet metal treated as a treadmill for a linear motor may be an indicator of damage to the material. Detection of places where the sheet does not meet the quality requirements may be very useful in the production process. FEM calculations were perfor...

  4. Calculation of shipboard fire conditions for radioactive materials packages with the methods of computational fluid dynamics

    International Nuclear Information System (INIS)

    Koski, J.A.; Wix, S.D.; Cole, J.K.

    1997-09-01

    Shipboard fires both in the same ship hold and in an adjacent hold aboard a break-bulk cargo ship are simulated with a commercial finite-volume computational fluid mechanics code. The fire models and modeling techniques are described and discussed. Temperatures and heat fluxes to a simulated materials package are calculated and compared to experimental values. The overall accuracy of the calculations is assessed

  5. Dynamic behavior of plasma-facing materials during plasma instabilities in tokamak reactors

    International Nuclear Information System (INIS)

    Hassanein, A.; Konkashbaev, I.

    1997-01-01

    Damage to plasma-facing and nearby components due to plasma instabilities remains a major obstacle to a successful tokamak concept. The high energy deposited on facing materials during plasma instabilities can cause severe erosion, plasma contamination, and structural failure of these components. Erosion damage can take various forms such as surface vaporization, spallation, and liquid ejection of metallic materials. Comprehensive thermodynamic and radiation hydrodynamic codes have been developed, integrated, and used to evaluate the extent of various damage to plasma-facing and nearby components. The eroded and splashed materials will be transported and then redeposited elsewhere on other plasma-facing components. Detailed physics of plasma/solid-liquid/vapor interaction in a strong magnetic field have been developed, optimized, and implemented in a self-consistent model. The plasma energy deposited in the evolving divertor debris is quickly and intensely reradiated, which may cause severe erosion and melting of other nearby components. Factors that influence and reduce vapor-shielding efficiency such as vapor diffusion and turbulence are also discussed and evaluated

  6. Sensor calibration of polymeric Hopkinson bars for dynamic testing of soft materials

    Science.gov (United States)

    Martarelli, Milena; Mancini, Edoardo; Lonzi, Barbara; Sasso, Marco

    2018-02-01

    Split Hopkinson pressure bar (SHPB) testing is one of the most common techniques for the estimation of the constitutive behaviour of metallic materials. In this paper, the characterisation of soft rubber-like materials has been addressed by means of polymeric bars thanks to their reduced mechanical impedance. Due to their visco-elastic nature, polymeric bars are more sensitive to temperature changes than metallic bars, and due to their low conductance, the strain gauges used to measure the propagating wave in an SHPB may be exposed to significant heating. Consequently, a calibration procedure has been proposed to estimate quantitatively the temperature influence on strain gauge output. Furthermore, the calibration is used to determine the elastic modulus of the polymeric bars, which is an important parameter for the synchronisation of the propagation waves measured in the input and output bar strain gate stations, and for the correct determination of stress and strain evolution within the specimen. An example of the application has been reported in order to demonstrate the effectiveness of the technique. Different tests at different strain rates have been carried out on samples made of nytrile butadyene rubber (NBR) from the same injection moulding batch. Thanks to the correct synchronisation of the measured propagation waves measured by the strain gauges and applying the calibrated coefficients, the mechanical behaviour of the NBR material is obtained in terms of strain-rate-strain and stress-strain engineering curves.

  7. Interaction of ozone with plastic and metallic materials in a dynamic flow system

    Energy Technology Data Exchange (ETDEWEB)

    Altshuller, A P; Wartburg, A F

    1961-01-01

    The loss of ozone in the p.p.h.m. range after passing through or over various plastic and metallic substances has been investigated. The materials used include Teflon, glass, stainless steel, aluminium, polyethylene and polyvinyl tubing, Mylar film, and aluminium foil. Unused Teflon passes ozone without loss. Glass tubing, after a short exposure to ozone, passes ozone without loss. Stainless steel tubing, aluminum tubing or foil and Mylar film must be exposed to ozone in the p.p.h.m. range for several hours before 90% or more of the ozone initially present can be passed through or over these materials. More rapid conditioning to ozone can be achieved by several five to fifteen-minute exposures to about 10 p.p.m. of ozone. Polyethylene and Nalgon tubing even after many hours of exposure to ozone will pass only 75 to 80% of the ozone initially present in the gas stream. Some types of polyvinyl tubing are unsatisfactory for use with ozone irrespective of the amount of exposure to ozone. Flowrates below 1000 c/sup 3//min. will increase losses of ozone. Except for Teflon and glass, materials should not be used in ozone analysis under any circumstances at low flowrates until they are thoroughly conditioned. Results obtained with stainless steel, aluminium and polyethylene indicate that conditioning to ozone once obtained will persist for at least two weeks.

  8. Molecular dynamics simulations of interactions between energetic dust and plasma-facing materials

    International Nuclear Information System (INIS)

    Niu, Guo-jian; Li, Xiao-chun; Xu, Qian; Yang, Zhong-shi; Luo, Guang-nan

    2015-01-01

    The interactions between dust and plasma-facing material (PFM) relate to the lifetime of PFM and impurity production. Series results have been obtained theoretically and experimentally but more detailed studies are needed. In present research, we investigate the evolution of kinetic, potential and total energy of plasma-facing material (PFM) in order to understand the dust/PFM interaction process. Three typical impacting energy are selected, i.e., 1, 10 and 100 keV/dust for low-, high- and hyper-energy impacting cases. For low impacting energy, dust particles stick on PFM surface without damaging it. Two typical time points exist and the temperature of PFM grows all the time but PFM structure experience a modifying process. Under high energy case, three typical points appear. The temperature curve fluctuates in the whole interaction process which indicates there are dust/PFM and kinetic/potential energy exchanges. In the hyper-energy case in present simulation, the violence dust/PFM interactions cause sputtering and crater investigating on energy evolution curves. We further propose the statistics of energy distribution. Results show that about half of impacting energy consumes on heating plasma-facing material meanwhile the other half on PFM structure deformation. Only a small proportion becomes kinetic energy of interstitial or sputtering atoms.

  9. Molecular dynamics simulations of interactions between energetic dust and plasma-facing materials

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Guo-jian, E-mail: niugj@ipp.ac.cn [Institute of Plasma Physics Chinese Academy of Sciences, Hefei (China); Li, Xiao-chun; Xu, Qian; Yang, Zhong-shi [Hefei Center Physical Science and Technology, Hefei (China); Luo, Guang-nan [Institute of Plasma Physics Chinese Academy of Sciences, Hefei (China); Hefei Center Physical Science and Technology, Hefei (China); Hefei Science Center of CAS, Hefei (China)

    2015-11-15

    The interactions between dust and plasma-facing material (PFM) relate to the lifetime of PFM and impurity production. Series results have been obtained theoretically and experimentally but more detailed studies are needed. In present research, we investigate the evolution of kinetic, potential and total energy of plasma-facing material (PFM) in order to understand the dust/PFM interaction process. Three typical impacting energy are selected, i.e., 1, 10 and 100 keV/dust for low-, high- and hyper-energy impacting cases. For low impacting energy, dust particles stick on PFM surface without damaging it. Two typical time points exist and the temperature of PFM grows all the time but PFM structure experience a modifying process. Under high energy case, three typical points appear. The temperature curve fluctuates in the whole interaction process which indicates there are dust/PFM and kinetic/potential energy exchanges. In the hyper-energy case in present simulation, the violence dust/PFM interactions cause sputtering and crater investigating on energy evolution curves. We further propose the statistics of energy distribution. Results show that about half of impacting energy consumes on heating plasma-facing material meanwhile the other half on PFM structure deformation. Only a small proportion becomes kinetic energy of interstitial or sputtering atoms.

  10. Coherent pulse interrogation system for fiber Bragg grating sensing of strain and pressure in dynamic extremes of materials.

    Science.gov (United States)

    Rodriguez, George; Jaime, Marcelo; Balakirev, Fedor; Mielke, Chuck H; Azad, Abul; Marshall, Bruce; La Lone, Brandon M; Henson, Bryan; Smilowitz, Laura

    2015-06-01

    A 100 MHz fiber Bragg grating (FBG) interrogation system is described and applied to strain and pressure sensing. The approach relies on coherent pulse illumination of the FBG sensor with a broadband short pulse from a femtosecond modelocked erbium fiber laser. After interrogation of the FBG sensor, a long multi-kilometer run of single mode fiber is used for chromatic dispersion to temporally stretch the spectral components of the reflected pulse from the FBG sensor. Dynamic strain or pressure induced spectral shifts in the FBG sensor are detected as a pulsed time domain waveform shift after encoding by the chromatic dispersive line. Signals are recorded using a single 35 GHz photodetector and a 50 G Samples per second, 25 GHz bandwidth, digitizing oscilloscope. Application of this approach to high-speed strain sensing in magnetic materials in pulsed magnetic fields to ~150 T is demonstrated. The FBG wavelength shifts are used to study magnetic field driven magnetostriction effects in LaCoO3. A sub-microsecond temporal shift in the FBG sensor wavelength attached to the sample under first order phase change appears as a fractional length change (strain: ΔL/L-4) in the material. A second application used FBG sensing of pressure dynamics to nearly 2 GPa in the thermal ignition of the high explosive PBX-9501 is also demonstrated. Both applications demonstrate the use of this FBG interrogation system in dynamical extreme conditions that would otherwise not be possible using traditional FBG interrogation approaches that are deemed too slow to resolve such events.

  11. The effects of topology on the structural, dynamic and mechanical properties of network-forming materials

    International Nuclear Information System (INIS)

    Wilson, Mark

    2012-01-01

    The effects of network topology on the static structural, mechanical and dynamic properties of MX 2 network-forming liquids (with tetrahedral short-range order) are discussed. The network topology is controlled via a single model parameter (the anion polarizability) which effectively constrains the inter-tetrahedral linkages in a physically transparent manner. Critically, it is found to control the balance between the stability of corner- and edge-sharing tetrahedra. A potential rigidity transformation is investigated. The vibrational density of states is investigated, using an instantaneous normal model analysis, as a function of both anion polarizability and temperature. A low frequency peak is seen to appear and is shown to be correlated with the fraction of cations which are linked through solely edge-sharing structural motifs. A modified effective mean atom coordination number is proposed which allows the appearance of the low frequency feature to be understood in terms of a mean field rigidity percolation threshold. (paper)

  12. Dynamic properties of micro-magnetic noise in soft ferromagnetic materials

    Science.gov (United States)

    Stupakov, A.; Perevertov, A.

    2018-06-01

    Dynamic response of magnetic hysteresis, magnetic Barkhausen noise and magneto-acoustic emission in a soft ribbon and electrical steels was studied comprehensively. The measurements were performed under controllable magnetization conditions: sinusoidal/triangular waveforms of the magnetic induction and a triangular waveform of the magnetic field. Magnetizing frequency was varied in a wide range: fmag = 0.5 - 500 and 0.5-100 Hz for the ribbon and the electrical steels, respectively. Magnetization amplitude was fixed on a near-saturation level Hmax ≃ 100 A/m. Barkhausen noise signal was detected by a sample-wrapping/surface-mounted coil and differently filtered. It was found that intensity of the Barkhausen noise rises approximately as a square root function of the magnetizing frequency. Whereas, level of the magneto-acoustic emission follows the hysteresis loss trend with an additional linear term (classical loss component).

  13. Isotrope und homogene Materie - Kosmen; On Dynamics and Thermodynamics of Isotropic Matter-Universes

    Science.gov (United States)

    Treder, H.-J.

    Die Dynamik und Thermodynamik großer kosmischer Systeme ist fast unabhängig von den besonderen Theorien über die Gravitation. Nur die Feinstruktur der Kosmologie und Kosmonogie reflektiert die speziellen Hypothesen. Diese Neutralität gegenüber den konkreten Gravodynamiken ist die Konsequenz der fundamentalen Eigenschaften der Gravitation: Der Prinzipien der Äquivalenz von Trägheit und Schwere. The dynamics and thermodynamics of great cosmical systems are nearly independent of the theory of gravitation and only the fine-structure of cosmogony and cosmology reflects the special hypotheses.The neutrality against the concret gravodynamics is a consequence of the fundamental properties of gravitation: the principlies of equivalence of gravity and inertia.

  14. Molecular dynamics modeling of bonding two materials by atomic scale friction stir welding

    Science.gov (United States)

    Konovalenko S., Iv.; Konovalenko, Ig. S.; Psakhie, S. G.

    2017-12-01

    Molecular dynamics model of atomic scale friction stir welding has been developed. Formation of a butt joint between two crystallites was modeled by means of rotating rigid conical tool traveling along the butt joint line. The formed joint had an intermixed atomic structure composed of atoms initially belonged to the opposite mated piece of metal. Heat removal was modeled by adding the extra viscous force to peripheral atomic layers. This technique provides the temperature control in the tool-affected zone during welding. Auxiliary vibration action was added to the rotating tool. The model provides the variation of the tool's angular velocity, amplitude, frequency and direction of the auxiliary vibration action to provide modeling different welding modes.

  15. Assessment of dynamic material properties of intact rocks using seismic wave attenuation: an experimental study.

    Science.gov (United States)

    Wanniarachchi, W A M; Ranjith, P G; Perera, M S A; Rathnaweera, T D; Lyu, Q; Mahanta, B

    2017-10-01

    The mechanical properties of any substance are essential facts to understand its behaviour and make the maximum use of the particular substance. Rocks are indeed an important substance, as they are of significant use in the energy industry, specifically for fossil fuels and geothermal energy. Attenuation of seismic waves is a non-destructive technique to investigate mechanical properties of reservoir rocks under different conditions. The attenuation characteristics of five different rock types, siltstone, shale, Australian sandstone, Indian sandstone and granite, were investigated in the laboratory using ultrasonic and acoustic emission instruments in a frequency range of 0.1-1 MHz. The pulse transmission technique and spectral ratios were used to calculate the attenuation coefficient ( α ) and quality factor ( Q ) values for the five selected rock types for both primary ( P ) and secondary ( S ) waves, relative to the reference steel sample. For all the rock types, the attenuation coefficient was linearly proportional to the frequency of both the P and S waves. Interestingly, the attenuation coefficient of granite is more than 22% higher than that of siltstone, sandstone and shale for both P and S waves. The P and S wave velocities were calculated based on their recorded travel time, and these velocities were then used to calculate the dynamic mechanical properties including elastic modulus ( E ), bulk modulus ( K ), shear modulus ( µ ) and Poisson's ratio ( ν ). The P and S wave velocities for the selected rock types varied in the ranges of 2.43-4.61 km s -1 and 1.43-2.41 km h -1 , respectively. Furthermore, it was observed that the P wave velocity was always greater than the S wave velocity, and this confirmed the first arrival of P waves to the sensor. According to the experimental results, the dynamic E value is generally higher than the static E value obtained by unconfined compressive strength tests.

  16. Material dynamics in polluted soils with different structures - comparative investigations of general soil and aggregates

    International Nuclear Information System (INIS)

    Taubner, H.

    1992-01-01

    In structured soils, a small-scale heterogeneity of physical and chemical properties will develop which results in a reduced availability of the reaction sites of the soil matrix. In view of the lack of knowledge on the conditions within the individual aggregates were carried out for characterizing the aggregates and comparing them with the soil in, general soil samples were taken from natural structure of a podzolic soil and a podazolic brown earth from two sites in the Fichtelgebirge mountains as well as a parabraun earth from East Holstein. The horizons differed with regard to their texture and structure; silty material tends to have a subpolyhedral structure and calyey material a polyhedral structure. The general soil samples and aggregate samples from the three B horizons were subjected, with comparable experimental conditions, to percolation experiments inducing a multiple acid load. The soil solution from the secondary pore system and aggregate pore system is more heterogeneus for the higher-structured subpolyhedral texture of the perdzolic soil than for the less strongly aggregated subpolyhedral structured of the podzolic brown earth. (orig.) [de

  17. Two Chaotic Patterns of Dynamic Risk Definition for Solving Hazardous Materials Routing Problem

    Directory of Open Access Journals (Sweden)

    Abbas Mahmoudabadi

    2015-01-01

    Full Text Available In the case of determining routes for hazardous material transportation, risk is considered as a main attribute. Transport risk, which is usually combined with other attributes such as cost or travel time, plays a significant role in determining paths for hazardous materials transportation. Since, risk is chaotically affected by road incidents, decision makers are dealing with selecting a method for defining chaotic risk factors in hazmat transportation. In this paper, transport risk has been defined as a chaotic variable using two different methods of generating chaotic patterns. In an experimental road network, which consists of eighty-nine nodes and one hundred and one two-way links, two different methods of generating chaotic variables have been used for applying the proposed procedure. In addition, results for different amounts of risk and cost have also been analyzed in case study. Results revealed that different cost and risk priorities change the frequencies of selected paths determined for hazmat transportation, but the route convergence of the route to chaos method is better than that of the logistic map equation.

  18. Dynamic impact response of high-density square honeycombs made of TRIP steel and TRIP matrix composite material

    Directory of Open Access Journals (Sweden)

    Weigelt C.

    2012-08-01

    Full Text Available Two designs of square-celled metallic honeycomb structures fabricated by a modified extrusion technology based on a powder feedstock were investigated. The strength and ductility of these cellular materials are achieved by an austenitic CrNi (AISI 304 steel matrix particle reinforced by an MgO partially-stabilized zirconia building up their cell wall microstructure. Similar to the mechanical behaviour of the bulk materials, the strengthening mechanism and the martensitic phase transformations in the cell walls are affected by the deformation temperature and the nominal strain rate. The microstructure evolution during quasi-static and dynamic impact compression up to high strain rates of 103 1/s influences the buckling and failure behaviour of the honeycomb structures. In contrast to bending-dominated quasi-isotropic networks like open-celled metal foams, axial compressive loading to the honeycomb’s channels causes membrane stretching as well as crushing of the vertical cell node elements and cell walls. The presented honeycomb materials differ geometrically in their cell wall thickness-to-cell size-ratio. Therefore, the failure behaviour is predominantly controlled by global buckling and torsional-flexural buckling, respectively, accompanied by plastic matrix flow and strengthening of the cell wall microstructure.

  19. Influence of bed material entrainment and non-Newtonian rheology on turbulent geophysical flows dynamics. Numerical study

    Science.gov (United States)

    Eglit, M. E.; Yakubenko, A. E.; Yakubenko, T. A.

    2017-10-01

    This paper deals with the mathematical and numerical modeling of the propagation stage of geophysical gravity-driven flows, such as snow avalanches, mudflows, and rapid landslides. New mathematical models are presented which are based on full, not-depth-averaged equations of mechanics of continuous media. The models account for three important issues: non-Newtonian rheology of the moving material, entrainment of the bed material by the flow, and turbulence. The main objective is to investigate the effect of these three factors on the flow dynamics and on the value of the entrainment rate. To exclude the influence of many other factors, e.g., the complicated slope topography, only the motion down a long uniform slope with a constant inclination angle is studied numerically. Moreover, the entire flow from the front to the rear area was not modeled, but only its middle part where the flow is approximately uniform in length. One of the qualitative results is that in motion along homogeneous slope the mass entrainment increases the flow velocity and depth while the entrainment rate at large time tends to become constant which depends on the physical properties of the flow and the underlying material but not on the current values of the flow velocity and depth.

  20. Dynamic High Pressure Study of Chemistry and Physics of Molecular Materials

    Science.gov (United States)

    Jezowski, Sebastian Ryszard

    Both temperature and pressure control and influence the packing of molecules in crystalline phases. Our molecular simulations indicate that at ambient pressure, the cubic polymorph of tetracyanoethylene, TCNE, is the energetically stable form up to ˜ 160 K. The observed transition from the cubic to the monoclinic polymorph occurs however only at temperatures above ˜ 318 K due to the large transition barrier. The temperature-induced phase transition in TCNE studied with high-resolution IR spectroscopy is explained in terms of the increased vibrational entropy in the crystals of the monoclinic polymorph. Based upon the inverted design of the Merril-Bassett Diamond Anvil Cell, an improved, second generation dynamic Diamond Anvil Cell was developed. Based on the fluorescence of ruby crystals, we were able to demonstrate that the pressure variation range can be further increased at least up to 7 kbar and that the dynamic pressure compression of up to 1400 GPa/s can be achieved. A new class of mechanophoric system, bis-anthracene, BA, and its photoisomer, PI, is shown to respond reversibly to a mild, static pressure induced by a Diamond Anvil Cell as well as to shear deformation based on absorption spectroscopic measurements. The forward reaction occurs upon illumination with light while the back-reaction may be accelerated upon heating or mechanical stress, coupled to a rehybridization on four equivalent carbon atoms. It is an intriguing result as high pressure stabilizes the photodimerized species in related systems. Our molecular volume simulations ruled out significant differences in the volumes between bis-anthracene and its photoisomer. Kinetic absorption measurements at several different pressures reveal a negative volume of activation in the exothermic back-reaction at room temperature. Through a series of temperature-dependent kinetic measurements it is shown that the barrier of activation for the back-reaction is reduced by more than an order of magnitude at

  1. A Simple Approach to Dynamic Material Balance in Gas-Condensate Reservoirs

    Directory of Open Access Journals (Sweden)

    Heidari Sureshjani M.

    2013-02-01

    Full Text Available In traditional material balance calculations, shut-in well pressure data are used to determine average reservoir pressure while recent techniques do not require the well to be shut-in and use instead flowing well pressure-rate data. These methods, which are known as “dynamic” material balance, are developed for single-phase flow (oil or gas in reservoirs. However, utilization of such methods for gas-condensate reservoirs may create significant errors in prediction of average reservoir pressure due to violation of the single-phase assumption in such reservoirs. In a previous work, a method for production data analysis in gas-condensate reservoirs was developed. The method required standard gas production rate, producing gas-oil ratio, flowing well pressure, CVD data and relative permeability curves. This paper presents a new technique which does not need relative permeability curves and flowing well pressure. In this method, the producing oil-gas ratio is interpolated in the vaporized oil in gas phase (Rv versus pressure (p data in the CVD table and the corresponding pressure is located. The parameter pressure/two-phase deviation factor (p/ztp is then evaluated at the determined pressure points and is plotted versus produced moles (np which forms a straight line. The nature of this plot is such that its extrapolation to point where p/ztp = 0 will give initial moles in place. Putting initial pressure/initial two-phase deviation factor (pi/ztp,i (known parameter and estimated initial moles (ni into the material balance equation, average reservoir pressure can be determined. A main assumption behind the method is that the region where both gas and condensate phases are mobile is of negligible size compared to the reservoir. The approach is quite simple and calculations are much easier than the previous work. It provides a practical engineering tool for industry studies as it requires data which are generally available in normal production

  2. Dynamic fracture toughness of ASME SA508 Class 2a ASME SA533 grade A Class 2 base and heat affected zone material and applicable weld metals

    International Nuclear Information System (INIS)

    Logsdon, W.A.; Begley, J.A.; Gottshall, C.L.

    1978-03-01

    The ASME Boiler and Pressure Vessel Code, Section III, Article G-2000, requires that dynamic fracture toughness data be developed for materials with specified minimum yield strengths greater than 50 ksi to provide verification and utilization of the ASME specified minimum reference toughness K/sub IR/ curve. In order to qualify ASME SA508 Class 2a and ASME SA533 Grade A Class 2 pressure vessel steels (minimum yield strengths equal 65 kip/in. 2 and 70 kip/in. 2 , respectively) per this requirement, dynamic fracture toughness tests were performed on these materials. All dynamic fracture toughness values of SA508 Class 2a base and HAZ material, SA533 Grade A Class 2 base and HAZ material, and applicable weld metals exceeded the ASME specified minimum reference toughness K/sub IR/ curve

  3. An Effective Modal Approach to the Dynamic Evaluation of Fracture Toughness of Quasi-Brittle Materials

    Science.gov (United States)

    Ferreira, L. E. T.; Vareda, L. V.; Hanai, J. B.; Sousa, J. L. A. O.; Silva, A. I.

    2017-05-01

    A modal dynamic analysis is used as the tool to evaluate the fracture toughness of concrete from the results of notched-through beam tests. The dimensionless functions describing the relation between the frequencies and specimen geometry used for identifying the variation in the natural frequency as a function of crack depth is first determined for a 150 × 150 × 500-mm notched-through specimen. The frequency decrease resulting from the propagating crack is modeled through a modal/fracture mechanics approach, leading to determination of an effective crack length. This length, obtained numerically, is used to evaluate the fracture toughness of concrete, the critical crack mouth opening displacements, and the brittleness index proposed. The methodology is applied to tests performed on high-strength concrete specimens. The frequency response for each specimen is evaluated before and after each crack propagation step. The methodology is then validated by comparison with results from the application of other methodologies described in the literature and suggested by RILEM.

  4. PHARMACEUTICAL AMORPHOUS ORGANIC MATERIALS CHARACTERIZATION BY USING THE DIFFERENTIAL SCANNING CALORIMETRY AND DYNAMIC MECHANICAL ANALYSIS

    Directory of Open Access Journals (Sweden)

    Ion Dranca

    2011-12-01

    Full Text Available This research has been carried out in order to demonstrate the use of differential scanning calorimetry (DSC in detecting and measuring α- and β-relaxation processes in amorphous pharmaceutical systems. DSC has been employed to study amorphous samples of poly (vinylpyrrolidone (PVP, indomethacin (InM, and ursodeoxycholic acid (UDA that are annealed at temperature (Ta around 0.8 of their glass transition temperature (Tg. Dynamic mechanical analysis (DMA is used to measure β- relaxation in PVP. Yet, the DSC has been used to study the glassy indomethacin aged at 0 and -10 oC for periods of time up to 109 and 210 days respectively. The results demonstrate the emergence of a small melting peak of the α-polymorph after aging for 69 days at 0°C and for 147 days at -10°C (i.e., ~55°C below the glass transition temperature that provides evidence of nucleation occurring in the temperature region of the β-relaxation.

  5. Improved Dynamic Analysis method for quantitative PIXE and SXRF element imaging of complex materials

    International Nuclear Information System (INIS)

    Ryan, C.G.; Laird, J.S.; Fisher, L.A.; Kirkham, R.; Moorhead, G.F.

    2015-01-01

    The Dynamic Analysis (DA) method in the GeoPIXE software provides a rapid tool to project quantitative element images from PIXE and SXRF imaging event data both for off-line analysis and in real-time embedded in a data acquisition system. Initially, it assumes uniform sample composition, background shape and constant model X-ray relative intensities. A number of image correction methods can be applied in GeoPIXE to correct images to account for chemical concentration gradients, differential absorption effects, and to correct images for pileup effects. A new method, applied in a second pass, uses an end-member phase decomposition obtained from the first pass, and DA matrices determined for each end-member, to re-process the event data with each pixel treated as an admixture of end-member terms. This paper describes the new method and demonstrates through examples and Monte-Carlo simulations how it better tracks spatially complex composition and background shape while still benefitting from the speed of DA.

  6. Dynamical nuclear safeguard investigations in nuclear materials using Analytic Pair Values

    International Nuclear Information System (INIS)

    Woo, Tae-Ho

    2011-01-01

    Highlights: → The quantification of the safeguard is performed to enhance operation safety. → Newly introduced maximum pair values with multiplications are obtained by the AHP method. → The dynamical simulations are performed based on the energy policy aspect. → The comparisons using NSP are possible. → A better operation skill is developed. - Abstract: The operation of nuclear power plants (NPPs) has been investigated from the view point of safeguard assessment. The risk of terrorist attack on NPPs is one of the critical points in the secure plant operations. The basic event of the related incidents is quantified by the random sampling using a Monte-Carlo method. The Analytic Hierarchy Process (AHP) is developed leading to the maximum pair values with multiplications which are decided by reactor characteristics. The matrix form analysis is compared with five NPP types of interest. Using a life cycle of 60 years, the range of the secure operation is between 0.020628 and 0.0212986, as relative numbers. This means the highest value in the range of secure power operation is about 1.043 times larger than the lowest one in this study. The consistency has the highest consistent values in the 24th and 54th years, as represented by C.I. (Consistency Index) and C.R. (Consistency Ratio). Finally, a nuclear safeguard protocol (NSP) is successfully constructed for the safe operation.

  7. Improved Dynamic Analysis method for quantitative PIXE and SXRF element imaging of complex materials

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, C.G., E-mail: chris.ryan@csiro.au; Laird, J.S.; Fisher, L.A.; Kirkham, R.; Moorhead, G.F.

    2015-11-15

    The Dynamic Analysis (DA) method in the GeoPIXE software provides a rapid tool to project quantitative element images from PIXE and SXRF imaging event data both for off-line analysis and in real-time embedded in a data acquisition system. Initially, it assumes uniform sample composition, background shape and constant model X-ray relative intensities. A number of image correction methods can be applied in GeoPIXE to correct images to account for chemical concentration gradients, differential absorption effects, and to correct images for pileup effects. A new method, applied in a second pass, uses an end-member phase decomposition obtained from the first pass, and DA matrices determined for each end-member, to re-process the event data with each pixel treated as an admixture of end-member terms. This paper describes the new method and demonstrates through examples and Monte-Carlo simulations how it better tracks spatially complex composition and background shape while still benefitting from the speed of DA.

  8. Development of a new dynamic method for quantitative evaluation of in vitro hemocompatibility of biomedical materials.

    Science.gov (United States)

    Groth, T; Vassilieff, C; Wolf, H; Richter, G; Foerster, F

    1992-01-01

    In this study a new dynamic method is introduced allowing the estimation of blood cell adhesion on flat test surfaces by measuring the cell loss in the bulk phase of surface contacting test blood under defined rheological conditions. This was achieved by constructing a novel test chamber permitting the contact of small amounts of blood with a large geometrical test surface. The construction consists of a spiral-shaped flow channel of 0.3 cm width, 0.02 cm height and 78 cm length covered with the biomaterials to be tested from both sides. Laminarity of blood flow in the conduit was confirmed theoretically by the calculation of an equivalent to the Reynolds number for curved systems the so-called Dean number. Furthermore, flow laminarity was proved experimentally finding that the flow rate of blood with different hematocrit values was proportional to the hydrostatic pressure applied. The applicability of the novel 'spiral method' for the estimation of hemocompatibility was demonstrated by evaluation of platelet adhesion onto different polymers in comparison to siliconized and fibrinogen coated glass as reference surfaces. Additionally, it was possible under distinct conditions to determine the adhesion of leucocytes and the detachment of platelet aggregates. Therefore, it was concluded that the spiral method can be used for the assessment of the hemocompatibility of flat biomedical polymers. As main advantages of the new method can be considered the high time efficiency and accuracy without labelling or optical detection of adherent cells.

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

    International Nuclear Information System (INIS)

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

    2002-01-01

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

  10. Dynamic thermal behavior of building using phase change materials for latent heat storage

    Directory of Open Access Journals (Sweden)

    Selka Ghouti

    2015-01-01

    Full Text Available This study presents a two-dimensional model with a real size home composed of two-storey (ground and first floor spaces separated by a slab, enveloped by a wall with rectangular section containing phase change material (PCM in order to minimize energy consumption in the buildings. The main objective of the PCM-wall system is to decrease the temperature change from outdoor space before it reaches the indoor space during the daytime. The numerical approach uses effective heat capacity Ceff model with realistic outdoor climatic conditions of Tlemcen city, Algeria. The numerical results showed that by using PCM in wall as energy storage components may reduce the room temperature by about 6 to 7°C of temperature depending on the floor level (first floor spaces or ground floor spaces.

  11. Air cleaning efficiency of deodorant materials under dynamic conditions: effect of air flow rate

    DEFF Research Database (Denmark)

    Mizutani, Chiyomi; Bivolarova, Mariya Petrova; Melikov, Arsen Krikor

    2014-01-01

    Unpleasant odor is a serious problem in hospitals and elderly facilities. One of the unpleasant odors is ammonia originating from human urine and sweat. The air cleaning efficiency of porous activated carbon fiber fabric which has been treated with acid, and porous activated carbon fiber fabric...... mixed with ammonia gas at a concentration of 20 ppm and velocities of 0.05, 0.15, 0.3 and 1.2 m/s. The activated carbon fibers treated with acid had a high deodorizing effect for ammonia (0.8) at a velocity of 0.05 m/s. The deodorizing effect of this material decreased with the increase in the velocity....... The porous activated carbon fiber fabric did not have a deodorant effect....

  12. Temporal response methods for dynamic measurement of in-process inventory of dissolved nuclear materials

    International Nuclear Information System (INIS)

    Ziri, S.M.; Seefeldt, W.B.

    1977-08-01

    This analysis has demonstrated that a plant's temporal response to perturbation of feed isotope composition can be used to measure the in-process inventory, without suspending plant operations. The main advantages of the temporal response technique over the step-displacement method are (1) it (the temporal response method) obviates the need for large special feed batches, and (2) it obviates the requirement that all the in-process material have a uniform isotopic composition at the beginning of the measurement. The temporal response method holds promise for essentially continuous real-time determination of in-process SNM. However, the temporal response method requires the measurement of the isotopic composition of many samples, and it works best for a stationary random input time series of tracer perturbations. Both of these requirements appear amenable to satisfaction by practical equipment and procedures if the benefits are deemed sufficiently worthwhile

  13. Temporal response methods for dynamic measurement of in-process inventory of dissolved nuclear materials

    International Nuclear Information System (INIS)

    Zivi, S.M.; Seefeldt, W.B.

    1976-01-01

    This analysis demonstrated that a plant's temporal response to perturbations of feed isotope composition can be used to measure the in-process inventory, without suspending plant operations. The main advantage of the temporal response technique over the step-displacement method are (1) it obviates the need for large special feed batches and (2) it obviates the requirement that all the in-process material have a uniform isotopic composition at the beginning of the measurement. The temporal response method holds promise for essentially continuous real-time determination of in-process SNM. The main disadvantage or problem with the temporal response method is that it requires the measurement of the isotopic composition of a great many samples to moderately high accuracy. This requirement appears amenable to solution by a modest effort in instrument development

  14. Molecular dynamics simulation of self-diffusion processes in titanium in bulk material, on grain junctions and on surface.

    Science.gov (United States)

    Sushko, Gennady B; Verkhovtsev, Alexey V; Yakubovich, Alexander V; Schramm, Stefan; Solov'yov, Andrey V

    2014-08-21

    The process of self-diffusion of titanium atoms in a bulk material, on grain junctions and on surface is explored numerically in a broad temperature range by means of classical molecular dynamics simulation. The analysis is carried out for a nanoscale cylindrical sample consisting of three adjacent sectors and various junctions between nanocrystals. The calculated diffusion coefficient varies by several orders of magnitude for different regions of the sample. The calculated values of the bulk diffusion coefficient correspond reasonably well to the experimental data obtained for solid and molten states of titanium. Investigation of diffusion in the nanocrystalline titanium is of a significant importance because of its numerous technological applications. This paper aims to reduce the lack of data on diffusion in titanium and describe the processes occurring in bulk, at different interfaces and on surface of the crystalline titanium.

  15. Dynamics

    CERN Document Server

    Goodman, Lawrence E

    2001-01-01

    Beginning text presents complete theoretical treatment of mechanical model systems and deals with technological applications. Topics include introduction to calculus of vectors, particle motion, dynamics of particle systems and plane rigid bodies, technical applications in plane motions, theory of mechanical vibrations, and more. Exercises and answers appear in each chapter.

  16. Real-Space Imaging of Carrier Dynamics of Materials Surfaces by Second-Generation Four-Dimensional Scanning Ultrafast Electron Microscopy

    KAUST Repository

    Sun, Jingya

    2015-09-14

    In the fields of photocatalysis and photovoltaics, ultrafast dynamical processes, including carrier trapping and recombination on material surfaces, are among the key factors that determine the overall energy conversion efficiency. A precise knowledge of these dynamical events on the nanometer (nm) and femtosecond (fs) scales was not accessible until recently. The only way to access such fundamental processes fully is to map the surface dynamics selectively in real space and time. In this study, we establish a second generation of four-dimensional scanning ultrafast electron microscopy (4D S-UEM) and demonstrate the ability to record time-resolved images (snapshots) of material surfaces with 650 fs and ∼5 nm temporal and spatial resolutions, respectively. In this method, the surface of a specimen is excited by a clocking optical pulse and imaged using a pulsed primary electron beam as a probe pulse, generating secondary electrons (SEs), which are emitted from the surface of the specimen in a manner that is sensitive to the local electron/hole density. This method provides direct and controllable information regarding surface dynamics. We clearly demonstrate how the surface morphology, grains, defects, and nanostructured features can significantly impact the overall dynamical processes on the surface of photoactive-materials. In addition, the ability to access two regimes of dynamical probing in a single experiment and the energy loss of SEs in semiconductor-nanoscale materials will also be discussed.

  17. Dynamic localisation of mature microRNAs in Human nucleoli is influenced by exogenous genetic materials.

    Science.gov (United States)

    Li, Zhou Fang; Liang, Yi Min; Lau, Pui Ngan; Shen, Wei; Wang, Dai Kui; Cheung, Wing Tai; Xue, Chun Jason; Poon, Lit Man; Lam, Yun Wah

    2013-01-01

    Although microRNAs are commonly known to function as a component of RNA-induced silencing complexes in the cytoplasm, they have been detected in other organelles, notably the nucleus and the nucleolus, of mammalian cells. We have conducted a systematic search for miRNAs in HeLa cell nucleoli, and identified 11 abundant miRNAs with a high level of nucleolar accumulation. Through in situ hybridisation, we have localised these miRNAs, including miR-191 and miR-484, in the nucleolus of a diversity of human and rodent cell lines. The nucleolar association of these miRNAs is resistant to various cellular stresses, but highly sensitive to the presence of exogenous nucleic acids. Introduction of both single- and double-stranded DNA as well as double stranded RNA rapidly induce the redistribution of nucleolar miRNAs to the cytoplasm. A similar change in subcellular distribution is also observed in cells infected with the influenza A virus. The partition of miRNAs between the nucleolus and the cytoplasm is affected by Leptomycin B, suggesting a role of Exportin-1 in the intracellular shuttling of miRNAs. This study reveals a previously unknown aspect of miRNA biology, and suggests a possible link between these small noncoding RNAs and the cellular management of foreign genetic materials.

  18. Dynamic localisation of mature microRNAs in Human nucleoli is influenced by exogenous genetic materials.

    Directory of Open Access Journals (Sweden)

    Zhou Fang Li

    Full Text Available Although microRNAs are commonly known to function as a component of RNA-induced silencing complexes in the cytoplasm, they have been detected in other organelles, notably the nucleus and the nucleolus, of mammalian cells. We have conducted a systematic search for miRNAs in HeLa cell nucleoli, and identified 11 abundant miRNAs with a high level of nucleolar accumulation. Through in situ hybridisation, we have localised these miRNAs, including miR-191 and miR-484, in the nucleolus of a diversity of human and rodent cell lines. The nucleolar association of these miRNAs is resistant to various cellular stresses, but highly sensitive to the presence of exogenous nucleic acids. Introduction of both single- and double-stranded DNA as well as double stranded RNA rapidly induce the redistribution of nucleolar miRNAs to the cytoplasm. A similar change in subcellular distribution is also observed in cells infected with the influenza A virus. The partition of miRNAs between the nucleolus and the cytoplasm is affected by Leptomycin B, suggesting a role of Exportin-1 in the intracellular shuttling of miRNAs. This study reveals a previously unknown aspect of miRNA biology, and suggests a possible link between these small noncoding RNAs and the cellular management of foreign genetic materials.

  19. Diffusion dynamics and concentration of toxic materials from quantum dots-based nanotechnologies: an agent-based modeling simulation framework

    Energy Technology Data Exchange (ETDEWEB)

    Agusdinata, Datu Buyung, E-mail: bagusdinata@niu.edu; Amouie, Mahbod [Northern Illinois University, Department of Industrial & Systems Engineering and Environment, Sustainability, & Energy Institute (United States); Xu, Tao [Northern Illinois University, Department of Chemistry and Biochemistry (United States)

    2015-01-15

    Due to their favorable electrical and optical properties, quantum dots (QDs) nanostructures have found numerous applications including nanomedicine and photovoltaic cells. However, increased future production, use, and disposal of engineered QD products also raise concerns about their potential environmental impacts. The objective of this work is to establish a modeling framework for predicting the diffusion dynamics and concentration of toxic materials released from Trioctylphosphine oxide-capped CdSe. To this end, an agent-based model simulation with reaction kinetics and Brownian motion dynamics was developed. Reaction kinetics is used to model the stability of surface capping agent particularly due to oxidation process. The diffusion of toxic Cd{sup 2+} ions in aquatic environment was simulated using an adapted Brownian motion algorithm. A calibrated parameter to reflect sensitivity to reaction rate is proposed. The model output demonstrates the stochastic spatial distribution of toxic Cd{sup 2+} ions under different values of proxy environmental factor parameters. With the only chemistry considered was oxidation, the simulation was able to replicate Cd{sup 2+} ion release from Thiol-capped QDs in aerated water. The agent-based method is the first to be developed in the QDs application domain. It adds both simplicity of the solubility and rate of release of Cd{sup 2+} ions and complexity of tracking of individual atoms of Cd at the same time.

  20. Effect of initial strain and material nonlinearity on the nonlinear static and dynamic response of graphene sheets

    Science.gov (United States)

    Singh, Sandeep; Patel, B. P.

    2018-06-01

    Computationally efficient multiscale modelling based on Cauchy-Born rule in conjunction with finite element method is employed to study static and dynamic characteristics of graphene sheets, with/without considering initial strain, involving Green-Lagrange geometric and material nonlinearities. The strain energy density function at continuum level is established by coupling the deformation at continuum level to that at atomic level through Cauchy-Born rule. The atomic interactions between carbon atoms are modelled through Tersoff-Brenner potential. The governing equation of motion obtained using Hamilton's principle is solved through standard Newton-Raphson method for nonlinear static response and Newmark's time integration technique to obtain nonlinear transient response characteristics. Effect of initial strain on the linear free vibration frequencies, nonlinear static and dynamic response characteristics is investigated in detail. The present multiscale modelling based results are found to be in good agreement with those obtained through molecular mechanics simulation. Two different types of boundary constraints generally used in MM simulation are explored in detail and few interesting findings are brought out. The effect of initial strain is found to be greater in linear response when compared to that in nonlinear response.

  1. Diffusion dynamics and concentration of toxic materials from quantum dots-based nanotechnologies: an agent-based modeling simulation framework

    International Nuclear Information System (INIS)

    Agusdinata, Datu Buyung; Amouie, Mahbod; Xu, Tao

    2015-01-01

    Due to their favorable electrical and optical properties, quantum dots (QDs) nanostructures have found numerous applications including nanomedicine and photovoltaic cells. However, increased future production, use, and disposal of engineered QD products also raise concerns about their potential environmental impacts. The objective of this work is to establish a modeling framework for predicting the diffusion dynamics and concentration of toxic materials released from Trioctylphosphine oxide-capped CdSe. To this end, an agent-based model simulation with reaction kinetics and Brownian motion dynamics was developed. Reaction kinetics is used to model the stability of surface capping agent particularly due to oxidation process. The diffusion of toxic Cd 2+ ions in aquatic environment was simulated using an adapted Brownian motion algorithm. A calibrated parameter to reflect sensitivity to reaction rate is proposed. The model output demonstrates the stochastic spatial distribution of toxic Cd 2+ ions under different values of proxy environmental factor parameters. With the only chemistry considered was oxidation, the simulation was able to replicate Cd 2+ ion release from Thiol-capped QDs in aerated water. The agent-based method is the first to be developed in the QDs application domain. It adds both simplicity of the solubility and rate of release of Cd 2+ ions and complexity of tracking of individual atoms of Cd at the same time

  2. Experimental study on the application of phase change material in the dynamic cycling of battery pack system

    International Nuclear Information System (INIS)

    Yan, Jiajia; Li, Ke; Chen, Haodong; Wang, Qingsong; Sun, Jinhua

    2016-01-01

    Highlights: • Two temperature peaks are observed in the single battery during the dynamic cycling. • The cooling performance of PCM system is superior to the natural convection system. • Increasing the laying-aside time is beneficial to the cooling performance of PCM system. • The optimal phase change temperature of PCM is recommended as 45 °C. - Abstract: The thermal performance of phase change material (PCM) based battery thermal management system in dynamic cycling is investigated, and several factors influencing the PCM system are discussed in detail. It is established that the surface temperature of a single battery has two temperature peaks during one charge/discharge cycle, while it disappears in the PCM system for the temperature buffering of PCM. In addition, the cooling performance of the PCM system is superior to that of natural convection system especially at a high current rate. Moreover, increasing the laying-aside time properly between each cycling step is beneficial to the cooling performance of the PCM system. Additionally, PCM with a phase change temperature of 45 °C is recommended to be used in the real battery pack system.

  3. Development of in situ time-resolved Raman spectroscopy facility for dynamic shock loading in materials

    Science.gov (United States)

    Chaurasia, S.; Rastogi, V.; Rao, U.; Sijoy, C. D.; Mishra, V.; Deo, M. N.

    2017-11-01

    The transient state of excitation and relaxation processes in materials under shock compression can be investigated by coupling the laser driven shock facility with Raman spectroscopy. For this purpose, a time resolved Raman spectroscopy setup has been developed to monitor the physical and the chemical changes such as phase transitions, chemical reactions, molecular kinetics etc., under shock compression with nanosecond time resolution. This system consist of mainly three parts, a 2 J/8 ns Nd:YAG laser system used for generation of pump and probe beams, a Raman spectrometer with temporal and spectral resolution of 1.2 ns and 3 cm-1 respectively and a target holder in confinement geometry assembly. Detailed simulation for the optimization of confinement geometry targets is performed. Time resolved measurement of polytetrafluoroethylene (PTFE) targets at focused laser intensity of 2.2 GW/cm2 has been done. The corresponding pressure in the Aluminum and PTFE are 3.6 and 1.7 GPa respectively. At 1.7 GPa in PTFE, a red shift of 5 cm-1 is observed for the CF2 twisting mode (291 cm-1). Shock velocity in PTFE is calculated by measuring rate of change of ratios of the intensity of Raman lines scattered from shocked volume to total volume of sample in the laser focal spot along the laser axis. The calculated shock velocity in PTFE is found to be 1.64 ± 0.16 km/s at shock pressure of 1.7 GPa, for present experimental conditions.

  4. Dynamics and Scaling Properties of Fractures in clay-like Materials

    Energy Technology Data Exchange (ETDEWEB)

    Walmann, Thomas

    1998-12-31

    Computer models that can help oil companies predict realistic and physically correct fracture patterns are important. To verify such a model, experiments described in this thesis were undertaken, using wet clay and powder. The main focus was on extensional fractures, but other types of fractures were also studied. High resolution digital images of the fracture patterns were recorded and analyzed using statistical physics and fractal geometry. The characteristic shapes and size distributions of individual fractures and the overall fracture patterns obtained from laboratory model studies were compared to results from aerial photographs of a fracture pattern in a collapsed glacier that had undergone a similar deformation. A new scaling relation (a power-law) between the length of a fracture and the projected area is derived for fractures formed during clay model experiments. This scaling relation is found also in a field study of a fracture pattern in a glacier. The forms of the different distributions that characterizes fractures in clay experiments are discussed. Several characteristic lengths are associated with the laboratory experiments. They are related to the sample size and shape, the model material and the nature of the imposed deformation. The roughness of the fracture traces obtained from powder experiments was found to have a self-affine form. The roughness, or Hurst exponent, was found to have the value 0.73, plus or minus 0.09. A large number of interacting fractures were formed in the systems studied, and under such conditions the fluctuations about the direction perpendicular to the principle strain direction are influenced by neighbouring fractures. As expected, an upper cutoff for the scaling range was observed. But the length at which the crossover from a self-affine shape to a flat shape took place did not depend systematically on any of the experimental parameters or characteristic length scales. The total fracture trace patterns could not be

  5. Modeling the Peano fluidic muscle and the effects of its material properties on its static and dynamic behavior

    Science.gov (United States)

    Veale, Allan Joshua; Xie, Sheng Quan; Anderson, Iain Alexander

    2016-06-01

    The promise of wearable assistive robotics cannot be realized without the development of actuators that mimic the behavior and form of biological muscles. Planar fluidic muscles known as Peano muscles or pouch motors have the potential to provide the high force and compliance of McKibben pneumatic artificial muscles with the low threshold pressure of pleated pneumatic artificial muscles. Yet they do so in a soft and slim form that can be discreetly distributed over the human body. This work is an investigation into the empirical modeling of the Peano muscle, the effect of its material on its performance, and its capabilities and limitations. We discovered that the Peano muscle could provide responsive and discreet actuation of soft and rigid bodies requiring strains between 15% and 30%. Ideally, they are made of non-viscoelastic materials with high tensile and low bending stiffnesses. While Sarosi et al’s empirical model accurately captures its static behavior with an root mean square error of 10.2 N, their dynamic model overestimates oscillation frequency and damping. We propose that the Peano muscle be modeled by a parallel ideal contractile unit and viscoelastic element, both in series with another viscoelastic element.

  6. Structural and dynamic properties of confined water in nanometric model porous materials (8 A≤diameter≤40 A)

    International Nuclear Information System (INIS)

    Floquet, N.; Coulomb, J.P.; Dufau, N.; Andre, G.; Kahn, R.

    2004-01-01

    Structural and dynamic properties of confined water have been investigated by 'in situ' neutron-scattering experiments. In the medium confinement regime (for MCM-41 host materials: 20 A≤diameter≤40 A) confined water has rather similar properties to bulk (3d) water. The major difference concerns the solidification phase transition. Strong triple-point depression ΔT 3t is observed and ΔT 3t increases when decreasing the pore diameter (213 K≤ΔT 3t ≤233 K). Such a confined water behaves as a supercooled liquid phase. The ultra-confinement (AlPO 4 -N zeolites: 8 A≤diameter≤12 A), is seen to induce the structuration of the confined water and its stability at room temperature T=300 K due to commensurability effect with the AlPO 4 -5 inner surface. No wetting phenomena are observed for both host materials, the silicic MCM-41 samples and the AlPO 4 -N zeolite family

  7. Experimental Study of Electron and Phonon Dynamics in Nanoscale Materials by Ultrafast Laser Time-Domain Spectroscopy

    Science.gov (United States)

    Shen, Xiaohan

    With the rapid advances in the development of nanotechnology, nowadays, the sizes of elementary unit, i.e. transistor, of micro- and nanoelectronic devices are well deep into nanoscale. For the pursuit of cheaper and faster nanoscale electronic devices, the size of transistors keeps scaling down. As the miniaturization of the nanoelectronic devices, the electrical resistivity increases dramatically, resulting rapid growth in the heat generation. The heat generation and limited thermal dissipation in nanoscale materials have become a critical problem in the development of the next generation nanoelectronic devices. Copper (Cu) is widely used conducting material in nanoelectronic devices, and the electron-phonon scattering is the dominant contributor to the resistivity in Cu nanowires at room temperature. Meanwhile, phonons are the main carriers of heat in insulators, intrinsic and lightly doped semiconductors. The thermal transport is an ensemble of phonon transport, which strongly depends on the phonon frequency. In addition, the phonon transport in nanoscale materials can behave fundamentally different than in bulk materials, because of the spatial confinement. However, the size effect on electron-phonon scattering and frequency dependent phonon transport in nanoscale materials remain largely unexplored, due to the lack of suitable experimental techniques. This thesis is mainly focusing on the study of carrier dynamics and acoustic phonon transport in nanoscale materials. The weak photothermal interaction in Cu makes thermoreflectance measurement difficult, we rather measured the reflectivity change of Cu induced by absorption variation. We have developed a method to separately measure the processes of electron-electron scattering and electron-phonon scattering in epitaxial Cu films by monitoring the transient reflectivity signal using the resonant probe with particular wavelengths. The enhancement on electron-phonon scattering in epitaxial Cu films with thickness

  8. In Situ Imaging of Particle Formation and Dynamics in Reactive Material Deflagrations

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, Kyle T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-12-12

    Reactive composites utilizing nanoparticles have been the topic of extensive research in the past two decades. The driver for this is that, as the particle size is decreased, the mixing scale between constituents is greatly reduced, which has long thought to increase the rate of chemical reaction. While a general trend of increased reactivity has been seen for metal / metal oxide, or thermite, reactive materials, some results have demonstrated diminishing returns as the particle size is further decreased. Recent results have shown that nanoparticles, which are typically aggregates of several primary particles, can undergo very rapid coalescence to form micron particles once a critical temperature is reached. Experiments on this topic to date have been performed on very small sample masses, and sometimes under vacuum; conditions which are not representative of the environment during a deflagration. In this feasibility study, a custom burn tube was used to ignite and react 100 mg powdered thermite samples in long acrylic tubes. X-ray imaging at APS Sector 32 was performed to image the particle field as a function of distance and time as the rarefied particle cloud expanded and flowed down the tube. Five different thermite formulations were investigated, Al / CuO, Al / Fe2O3, Al / SnO2, Al / WO3, and Al / Fe2O3, along with Al / CuO formulations with different sizes of Al particles ranging from 80 nm to approximate 10 μm. The results clearly show that the sample powder reacts and unloads into a distribution of larger micron-scale particles (~5-500 μm), which continue to react and propagate as the particle-laden stream flows down the tube. This was the first direct imaging of the particle field during a thermite deflagration, and gives significant insight into the evolution of reactants to products. Analysis of phase is currently being pursued to determine whether this method can be used to extract

  9. Experimental study of implosion dynamics of multi-material nested wire-arrays on S-300 pulsed power generator

    International Nuclear Information System (INIS)

    Chernenko, A.S.; Smirnov, V.P.; Kingsep, A.S.

    2004-01-01

    On 'S-300' generator (700 kV, 4 MA, 70 ns) at the Kurchatov Institute, the experimental studies with multi-material wire array units are carried on aimed at creating the powerful X-ray source. The development of new diagnostic methods would definitely contribute to attain new data, which could help in explanation of X-ray emission mechanism of imploding multi-wire arrays that has not well understood yet. The experimental study of soft X-ray emission of different wire sets, different in both mass and composition, has been carried on in the same geometry. One of the purposes of these experiments was investigation of the wire array chemical composition influence on the implosion dynamics and stability. Study of the nested (cascade) liner dynamics shows that the minimal liner radius at the stagnation moment of time (2r ∼ 3 - 3.5 mm) recorded in the visible range by the streak camera fairly coincides with the outer diameter of the inner tungsten array of 4 mm. The same size is shown by the integral pinhole pictures obtained in the SXR range, without a filter. Unlike all these pictures, images obtained in the range E > 2 keV demonstrate the resulting state of Z-pinch in the form of a thin (∼ 0.2 mm) twisting filament. In addition, small space scales are typical of the liner pictures taken in the range of He- and H-like aluminum ions by means of a spectrograph. Thus, one may conclude that Al plasma of the outer liner passes into the inner space of the almost immovable W array where becomes trapped and compressed by the magnetic field. (author)

  10. [?]Nonlinear Issues in the Aerothermochemistry of Gases and Materials and the Associated Physics and Dynamics of Interfaces

    Science.gov (United States)

    Johnson, Joseph A., III

    1996-01-01

    Our research and technology are focused on nonlinear issues in the aerothermochemistry of gases and materials and the associated physics and dynamics of interfaces. Our program is now organized to aggressively support the NASA Aeronautics Enterprise so as to: (a) develop a new generation of environmentally compatible, economic subsonic aircraft; (b) develop the technology base for an economically viable and environmentally compatible high-speed civil transport; (c) develop the technology options for new capabilities in high-performance aircraft; (d) develop hypersonic technologies for air-breathing flight; and (e) develop advanced concepts, understanding of physical phenomena, and theoretical, experimental, and computational tools for advanced aerospace systems. The implications from our research for aeronautical and aerospace technology have been both broad and deep. For example, using advanced computational techniques, we have determined exact solutions for the Schrodinger equation in electron-molecule scattering allowing us to evaluate atmospheric models important to reentry physics. We have also found a new class of exact solutions for the Navier Stokes equations. In experimental fluid dynamics, we have found explicit evidence of turbulence modification of droplet sizes in shock tube flow with condensation. We have developed a new diagnostic tool for the direct estimation of flow velocities at MHz sampling rates in quasi-one dimensional turbulent flow. This procedure suggests an unexpected confirmation of the possibility of 'natural' closure in Reynolds stresses with deep implications for the development of turbulent models. A transient increase is observed in both the spectral energy decay rate and the degree of chaotic complexity at the interface of a shock wave and a turbulent ionized gas. Even though the gas is apparently brought to rest by the shock wave, no evidence is found either of the expected relaminarization. A unique diamond-shaped nozzle has been

  11. Rational molecular dynamics scheme for predicting optimum concentration loading of nano-additive in phase change materials

    Directory of Open Access Journals (Sweden)

    Monisha Rastogi

    2015-10-01

    Full Text Available The present study deals with the diffusion and phase transition behaviour of paraffin reinforced with carbon nano-additives namely graphene oxide (GO and surface functionalized single walled carbon nanotubes (SWCNT. Bulk disordered systems of paraffin hydrocarbons impregnated with carbon nano-additives have been generated in realistic equilibrium conformations for potential application as latent heat storage systems. Ab initio molecular dynamics(MD in conjugation with COMPASS forcefield has been implemented using periodic boundary conditions. The proposed scheme allows determination of optimum nano-additive loading for improving thermo-physical properties through analysis of mass, thermal and transport properties; and assists in determination of composite behaviour and related performance from microscopic point of view. It was observed that nanocomposites containing 7.8 % surface functionalised SWCNT and 55% GO loading corresponds to best latent heat storage system. The propounded methodology could serve as a by-pass route for economically taxing and iterative experimental procedures required to attain the optimum composition for best performance. The results also hint at the large unexplored potential of ab-initio classical MD techniques for predicting performance of new nanocomposites for potential phase change material applications.

  12. Molecular dynamics simulations of the lattice thermal conductivity of thermoelectric material CuInTe{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Wei, J. [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Kowloon Tong (Hong Kong); Liu, H.J., E-mail: phlhj@whu.edu.cn [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Cheng, L.; Zhang, J.; Jiang, P.H.; Liang, J.H.; Fan, D.D.; Shi, J. [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 (China)

    2017-05-10

    Highlights: • A simple but effective Morse potential is constructed to accurately describe the interatomic interactions of CuInTe{sub 2}. • The lattice thermal conductivity of CuInTe{sub 2} predicted by MD agrees well with those measured experimentally, as well as those calculated from phonon BTE. • Introducing Cd impurity or Cu vacancy can effectively reduce the lattice thermal conductivity of CuInTe{sub 2} and thus further enhance its thermoelectric performance. - Abstract: The lattice thermal conductivity of thermoelectric material CuInTe{sub 2} is predicted using classical molecular dynamics simulations, where a simple but effective Morse-type interatomic potential is constructed by fitting first-principles total energy calculations. In a broad temperature range from 300 to 900 K, our simulated results agree well with those measured experimentally, as well as those obtained from phonon Boltzmann transport equation. By introducing the Cd impurity or Cu vacancy, the thermal conductivity of CuInTe{sub 2} can be effectively reduced to further enhance the thermoelectric performance of this chalcopyrite compound.

  13. Rational molecular dynamics scheme for predicting optimum concentration loading of nano-additive in phase change materials

    Science.gov (United States)

    Rastogi, Monisha; Vaish, Rahul; Madhar, Niyaz Ahamad; Shaikh, Hamid; Al-Zahrani, S. M.

    2015-10-01

    The present study deals with the diffusion and phase transition behaviour of paraffin reinforced with carbon nano-additives namely graphene oxide (GO) and surface functionalized single walled carbon nanotubes (SWCNT). Bulk disordered systems of paraffin hydrocarbons impregnated with carbon nano-additives have been generated in realistic equilibrium conformations for potential application as latent heat storage systems. Ab initio molecular dynamics(MD) in conjugation with COMPASS forcefield has been implemented using periodic boundary conditions. The proposed scheme allows determination of optimum nano-additive loading for improving thermo-physical properties through analysis of mass, thermal and transport properties; and assists in determination of composite behaviour and related performance from microscopic point of view. It was observed that nanocomposites containing 7.8 % surface functionalised SWCNT and 55% GO loading corresponds to best latent heat storage system. The propounded methodology could serve as a by-pass route for economically taxing and iterative experimental procedures required to attain the optimum composition for best performance. The results also hint at the large unexplored potential of ab-initio classical MD techniques for predicting performance of new nanocomposites for potential phase change material applications.

  14. Dynamic analysis of a needle insertion for soft materials: Arbitrary Lagrangian-Eulerian-based three-dimensional finite element analysis.

    Science.gov (United States)

    Yamaguchi, Satoshi; Tsutsui, Kihei; Satake, Koji; Morikawa, Shigehiro; Shirai, Yoshiaki; Tanaka, Hiromi T

    2014-10-01

    Our goal was to develop a three-dimensional finite element model that enables dynamic analysis of needle insertion for soft materials. To demonstrate large deformation and fracture, we used the arbitrary Lagrangian-Eulerian (ALE) method for fluid analysis. We performed ALE-based finite element analysis for 3% agar gel and three types of copper needle with bevel tips. To evaluate simulation results, we compared the needle deflection and insertion force with corresponding experimental results acquired with a uniaxial manipulator. We studied the shear stress distribution of agar gel on various time scales. For 30°, 45°, and 60°, differences in deflections of each needle between both sets of results were 2.424, 2.981, and 3.737mm, respectively. For the insertion force, there was no significant difference for mismatching area error (p<0.05) between simulation and experimental results. Our results have the potential to be a stepping stone to develop pre-operative surgical planning to estimate an optimal needle insertion path for MR image-guided microwave coagulation therapy and for analyzing large deformation and fracture in biological tissues. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Application of the Real-Time Time-Dependent Density Functional Theory to Excited-State Dynamics of Molecules and 2D Materials

    Science.gov (United States)

    Miyamoto, Yoshiyuki; Rubio, Angel

    2018-04-01

    We review our recent developments in the ab initio simulation of excited-state dynamics within the framework of time-dependent density functional theory (TDDFT). Our targets range from molecules to 2D materials, although the methods are general and can be applied to any other finite and periodic systems. We discuss examples of excited-state dynamics obtained by real-time TDDFT coupled with molecular dynamics (MD) and the Ehrenfest approximation, including photoisomerization in molecules, photoenhancement of the weak interatomic attraction of noble gas atoms, photoenhancement of the weak interlayer interaction of 2D materials, pulse-laser-induced local bond breaking of adsorbed atoms on 2D sheets, modulation of UV light intensity by graphene nanoribbons at terahertz frequencies, and collision of high-speed ions with the 2D material to simulate the images taken by He ion microscopy. We illustrate how the real-time TDDFT approach is useful for predicting and understanding non-equilibrium dynamics in condensed matter. We also discuss recent developments that address the excited-state dynamics of systems out of equilibrium and future challenges in this fascinating field of research.

  16. Dramatic effect of pore size reduction on the dynamics of hydrogen adsorbed in metal–organic materials

    KAUST Repository

    Nugent, Patrick

    2014-07-21

    The effects of pore size reduction on the dynamics of hydrogen sorption in metal-organic materials (MOMs) were elucidated by studying SIFSIX-2-Cu and its doubly interpenetrated polymorph SIFSIX-2-Cu-i by means of sorption, inelastic neutron scattering (INS), and computational modeling. SIFSIX-2-Cu-i exhibits much smaller pore sizes, which possess high H2 sorption affinity at low loadings. Experimental H2 sorption measurements revealed that the isosteric heat of adsorption (Qst) for H2 in SIFSIX-2-Cu-i is nearly two times higher than that for SIFSIX-2-Cu (8.6 vs. 4.6 kJ mol-1). The INS spectrum for H2 in SIFSIX-2-Cu-i is rather unique for a porous material, as only one broad peak appears at low energies near 6 meV, which simply increases in intensity with loading until the pores are filled. The value for this rotational transition is lower than that in most neutral metal-organic frameworks (MOFs), including those with open Cu sites (8-9 meV), which is indicative of a higher barrier to rotation and stronger interaction in the channels of SIFSIX-2-Cu-i than the open Cu sites in MOFs. Simulations of H2 sorption in SIFSIX-2-Cu-i revealed two hydrogen sorption sites in the MOM: direct interaction with the equatorial fluorine atom (site 1) and between two equatorial fluorine atoms on opposite walls (site 2). The calculated rotational energy levels and rotational barriers for the two sites in SIFSIX-2-Cu-i are in good agreement with INS data. Furthermore, the rotational barriers and binding energies for site 2 are slightly higher than that for site 1, which is consistent with INS results. The lowest calculated transition for the primary site in SIFSIX-2-Cu is also in good agreement with INS data. In addition, this transition in the non-interpenetrating material is higher than any of the sites in SIFSIX-2-Cu-i, which indicates a significantly weaker interaction with the host as a result of the larger pore size. This journal is © the Partner Organisations 2014.

  17. Method of rheological characterization of polymer materials by identification of the prony viscoelastic model according to data of static and dynamic accelerated tests

    Science.gov (United States)

    Shil'ko, S. V.; Gavrilenko, S. L.; Panin, S. V.; Alexenko, V. O.

    2017-12-01

    A method for determining rheological parameters of the Prony model describing the process of viscoelastic deformation of a material was developed based on the results of dynamic mechanical analysis. For the approbation of the method, static (uniaxial tension) and dynamic (three-point bending) mechanical tests of polymer composites were carried out. Based on the analytical dependence of the storage modulus on the parameters of the Prony model, the parameters of the shear function are determined. The results of the static and dynamic analysis are in good agreement. The proposed technique allows us to accelerate the determination of rheological parameters of polymer materials and recommend it to the calculation of the stress-strain state of structural elements and friction joints during their long operation at elevated temperature.

  18. Novel Approaches to Spectral Properties of Correlated Electron Materials: From Generalized Kohn-Sham Theory to Screened Exchange Dynamical Mean Field Theory

    Science.gov (United States)

    Delange, Pascal; Backes, Steffen; van Roekeghem, Ambroise; Pourovskii, Leonid; Jiang, Hong; Biermann, Silke

    2018-04-01

    The most intriguing properties of emergent materials are typically consequences of highly correlated quantum states of their electronic degrees of freedom. Describing those materials from first principles remains a challenge for modern condensed matter theory. Here, we review, apply and discuss novel approaches to spectral properties of correlated electron materials, assessing current day predictive capabilities of electronic structure calculations. In particular, we focus on the recent Screened Exchange Dynamical Mean-Field Theory scheme and its relation to generalized Kohn-Sham Theory. These concepts are illustrated on the transition metal pnictide BaCo2As2 and elemental zinc and cadmium.

  19. A prototype system dynamic model of nuclear and radiological export controls in Central Asia and the Caucasus; enhancing the effectiveness of preventing illicit nuclear material trafficking

    International Nuclear Information System (INIS)

    Ferguston, C.D.; Ouagrham, S.B.

    2002-01-01

    An urgent need calls out for improved border security and export control systems in the Central Asian and Caucasus regions to prevent illicit nuclear and radioactive materials trafficking. Effective nuclear and radiological exports controls are essential because these regions contain numerous nuclear facilities and radioactive materials as well as lie at the crossroads between seekers and suppliers of technologies that could be employed in nuclear and radiological weapons. Porous and unprotected borders compound these concerns. Moreover, the states within these regions are struggling with forming new regulations and laws, obtaining sufficient portal monitoring equipment, training customs and border security personnel, and coordinating these activities with neighboring states. Building this infrastructure all at once can severely task any government. Thus, unsurprisingly, most of these states have inadequate export control and border security systems. To enable each state in these regions determine how to better prevent illicit nuclear and radiological materials trafficking, the authors have developed a prototype system dynamics model focused on evaluating and improving of effectiveness of export controls. System dynamics modeling, a management tool that grew out of the field of system engineering and nonlinear dynamics, uses two structures: causal loop diagrams and stock and flow diagrams. The former shows how endogenous systematic factors interact with each other to produce feedback mechanisms that results in either balancing or reinforcing loops. A classic example is a arms race, modeled as a vicious cycle or reinforcing loop. In addition to interacting with each other, causal loops influence the flow of stock, which is material concern. In the export control system dynamics model, the stock represents nuclear and radioactive materials. System dynamics modelling is an iterative process that is continually modified by user input. Therefore, export control

  20. Superoxide generation is diminished during glucose-stimulated insulin secretion in INS-1E cells

    Czech Academy of Sciences Publication Activity Database

    Ježek, Petr; Hlavatá, Lydie; Špaček, Tomáš

    2008-01-01

    Roč. 275, Suppl.1 (2008), s. 310-310 ISSN 1742-464X. [FEBS Congress /33./ and IUBMB Conference /11./. 28.06.2008-03.07.2008, Athens] R&D Projects: GA MZd(CZ) NR7917; GA AV ČR(CZ) IAA500110701 Institutional research plan: CEZ:AV0Z50110509 Keywords : cpo1 * superoxide production * glucose-stimulated insulin secretion * INS-1E cells Subject RIV: ED - Physiology

  1. Dynamic NMR studies of polymer electrolyte materials for application to lithium-ion batteries and fuel cells

    Science.gov (United States)

    Khalfan, Amish N.

    This dissertation investigates the structural and dynamical properties of polymer electrolyte materials for applications to lithium-ion batteries and fuel cells. The nuclear magnetic resonance (NMR) technique was used to characterize these materials. NMR aids in understanding the local environments of nuclei and the mobility of a molecular/ionic species. Five research projects were carried out, and they have been outlined in this work. NASA has developed rod-coil block copolymers for use as electrolytes in lithium-ion batteries. The copolymers exhibit a microphase separation within their structure leading to the formation of ionically conducting channels. We studied ion transport properties of the copolymers, and determined the predominant mechanism for transport to occur in the amorphous phase. Seven gel polymer electrolytes, each containing a mixture of LiBETI salt and organic solvents, were studied. Two of them incorporated BMI (1-n-butyl-3-methylimidazolium) ionic liquid. Ionic liquids are room temperature molten salts. BMI had been thought to enhance ion mobility. However, the BMI component was observed to restrict ion mobility. Gel polymer electrolytes containing LiTFSI salt and P13TFSI ionic liquid with or without the inclusion of ethylene carbonate (EC) were studied for application to lithium metal/air batteries, which have high theoretical energy densities. The addition of EC was found to improve lithium ion transport. The gels with EC therefore prove to be favorable for use as electrolytes in lithium metal/air batteries. Highly sulfonated poly(arylenethioethersulfone) (SPTES) membranes were examined for use in direct methanol fuel cells (DMFCs) as an alternative to the Nafion membrane. DMFCs use methanol as a fuel instead of reformed hydrogen as in conventional proton exchange membrane fuel cells. Compared to Nafion, the SPTES membranes were shown to retain water better at high temperatures and yield lower methanol diffusion. SPTES membranes with the

  2. Glutamine synthetase gene knockout-human embryonic kidney 293E cells for stable production of monoclonal antibodies.

    Science.gov (United States)

    Yu, Da Young; Lee, Sang Yoon; Lee, Gyun Min

    2018-05-01

    Previously, it was inferred that a high glutamine synthetase (GS) activity in human embryonic kidney (HEK) 293E cells results in elevated resistance to methionine sulfoximine (MSX) and consequently hampers GS-mediated gene amplification and selection by MSX. To overcome this MSX resistance in HEK293E cells, a GS-knockout HEK293E cell line was generated using the CRISPR/Cas9 system to target the endogenous human GS gene. The GS-knockout in the HEK293E cell line (RK8) was confirmed by Western blot analysis of GS and by observation of glutamine-dependent growth. Unlike the wild type HEK293E cells, the RK8 cells were successfully used as host cells to generate a recombinant HEK293E cell line (rHEK293E) producing a monoclonal antibody (mAb). When the RK8 cells were transfected with the GS expression vector containing the mAb gene, rHEK293E cells producing the mAb could be selected in the absence as well as in the presence of MSX. The gene copies and mRNA expression levels of the mAb in rHEK293E cells were also quantified using qRT-PCR. Taken together, the GS-knockout HEK293E cell line can be used as host cells to generate stable rHEK293E cells producing a mAb through GS-mediated gene selection in the absence as well as in the presence of MSX. © 2018 Wiley Periodicals, Inc.

  3. NMR studies of organic liquids confined in mesoporous materials: (1) Pore size distribution and (2) Phase behaviour and dynamic studies in restricted geometry

    International Nuclear Information System (INIS)

    Foerland, Kjersti

    2005-01-01

    In the thesis NMR spectroscopy is used for studying liquids confined in various porous materials. In the first part, pore size distributions of mesoporous silicas and controlled pore glasses were determined by measuring the 1H NMR signal from the non-frozen fraction of the confined liquid as a function of temperature, using benzene, acetonitrile and HMDS as probe molecules. In the second part, the molecular dynamics of acetonitrile, hexamethyldisilane, cyclohexane and cyclopentane confined in mesoporous materials were studied as a function of temperature. 6 papers are included with titles: 1) Pore-size determination of mesoporous materials by 1H NMR spectroscopy. 2) Pore-size distribution in mesoporous materials as studied by 1H NMR. 3) Dynamic 1H and 2H NMR investigations of acetonitrile confined in porous silica. 4) NMR investigations of hexamethyldisilane confined in controlled pore glasses: Pore size distribution and molecular dynamics studies. 5) 1H and 2H NMR studies of cyclohexane nano crystals in controlled pore glasses. 6) 1H NMR relaxation and diffusion studies of cyclohexane and cyclopentane confined in MCM-41

  4. NMR studies of organic liquids confined in mesoporous materials: (1) Pore size distribution and (2) Phase behaviour and dynamic studies in restricted geometry

    Energy Technology Data Exchange (ETDEWEB)

    Foerland, Kjersti

    2005-07-01

    In the thesis NMR spectroscopy is used for studying liquids confined in various porous materials. In the first part, pore size distributions of mesoporous silicas and controlled pore glasses were determined by measuring the 1H NMR signal from the non-frozen fraction of the confined liquid as a function of temperature, using benzene, acetonitrile and HMDS as probe molecules. In the second part, the molecular dynamics of acetonitrile, hexamethyldisilane, cyclohexane and cyclopentane confined in mesoporous materials were studied as a function of temperature. 6 papers are included with titles: 1) Pore-size determination of mesoporous materials by 1H NMR spectroscopy. 2) Pore-size distribution in mesoporous materials as studied by 1H NMR. 3) Dynamic 1H and 2H NMR investigations of acetonitrile confined in porous silica. 4) NMR investigations of hexamethyldisilane confined in controlled pore glasses: Pore size distribution and molecular dynamics studies. 5) 1H and 2H NMR studies of cyclohexane nano crystals in controlled pore glasses. 6) 1H NMR relaxation and diffusion studies of cyclohexane and cyclopentane confined in MCM-41.

  5. Study of the effect of composition and construction of material on sub-bandage pressure during dynamic loading of a limb in vitro.

    Science.gov (United States)

    Kumar, Bipin; Das, Apurba; Alagirusamy, R

    2013-01-01

    Internal stress in a compression bandage wrapped over a limb in vitro is expected to reduce over time because of fatigue which may occur due to repetitive and prolonged variations in the extension of the bandage during posture change and exercise. This phenomenon may cause significant variation in the sub-bandage pressure over time. To examine the effect of composition and construction of material on the sub-bandage pressure variation over time in the dynamic state of a limb in the laboratory. Yarns comprising fibers of polyester, viscose, cotton and elastomeric yarn were used to prepare different knitted bandage samples having varying thread densities in the structure. A leg-segment prototype was used for the measurement of the interface pressure over a mannequin limb to analyse different bandages under similar dynamic conditions. The pressure drop in the dynamic state of the mannequin limb was greater than that in the static state. The mean pressure drop in 2 h in the dynamic state was greater by >30% for bandages made of pure cotton or viscose yarns than for bandages having elastomeric yarns in their structure. At the same applied tension, increasing the number of yarns per unit length in the bandage structure resulted in a smaller drop in pressure in the dynamic mode. Elastomeric yarn improves the elasticity and fatigue resistance of the bandage. Therefore, these yarns should be used in bandages to obtain sustained compression effects under dynamic conditions.

  6. Dynamic Test Method Based on Strong Electromagnetic Pulse for Electromagnetic Shielding Materials with Field-Induced Insulator-Conductor Phase Transition

    Science.gov (United States)

    Wang, Yun; Zhao, Min; Wang, Qingguo

    2018-01-01

    In order to measure the pulse shielding performance of materials with the characteristic of field-induced insulator-conductor phase transition when materials are used for electromagnetic shielding, a dynamic test method was proposed based on a coaxial fixture. Experiment system was built by square pulse source, coaxial cable, coaxial fixture, attenuator, and oscilloscope and insulating components. S11 parameter of the test system was obtained, which suggested that the working frequency ranges from 300 KHz to 7.36 GHz. Insulating performance is good enough to avoid discharge between conductors when material samples is exposed in the strong electromagnetic pulse field up to 831 kV/m. This method is suitable for materials with annular shape, certain thickness and the characteristic of field-induced insulator-conductor phase transition to get their shielding performances of strong electromagnetic pulse.

  7. Modelling the effects of phase change materials on the energy use in buildings. Results of Experiments and System Dynamics Modelling

    Energy Technology Data Exchange (ETDEWEB)

    Prins, J.

    2012-02-15

    The current era is in need for more and more sustainable energy solutions. Phase Change Materials (PCM's) are a solution for a more sustainable build environment because they can help to reduce the energy use of buildings during heating and cooling of the indoor air. This paper presents the results of recent experiments that have been executed with test boxes. In addition a System Dynamics model has been developed to find out how PCM's can be used efficiently without testing in reality. The first experiment, in which PCM's were applied in a concrete floor, shows a reduction of peak temperatures with 4C {+-} 0.7C on maximum temperatures and over 1.5C {+-} 0.7C on minimum temperatures during warm periods. The model confirmed these findings, although the predicted reductions were slightly. During the second experiment more PCM's were applied by mounting them into the walls using gypsum plasterboard to increase the latent heat capacity. Remarkably, both the experimental set-up as the model showed that the increase of PCM's (of almost 98%) causes hardly any difference compared to the first situation. Adapting the exterior in a way to absorb more solar energy, increases the average indoor temperature but decreases the reduction of peak temperatures. Again the model confirmed these findings of the experiment. These results show that the effect of PCM's varies on different climatological contexts and with different construction components physics. This means no straight forward advice on the use of PCM's for a building design can be given. The solution for this problem is provided by the model, showing that the effects of PCM's can be modelled in order to use PCM's in an effective way in different climatological contexts and with different characteristics of construction components. The research shows that a simple model is already capable of predicting PCM performance in test boxes with reasonable accuracy. Therefore it can be

  8. Dynamic Processes in Biology, Chemistry, and Materials Science: Opportunities for UltraFast Transmission Electron Microscopy - Workshop Summary Report

    Energy Technology Data Exchange (ETDEWEB)

    Kabius, Bernd C.; Browning, Nigel D.; Thevuthasan, Suntharampillai; Diehl, Barbara L.; Stach, Eric A.

    2012-07-25

    This report summarizes a 2011 workshop that addressed the potential role of rapid, time-resolved electron microscopy measurements in accelerating the solution of important scientific and technical problems. A series of U.S. Department of Energy (DOE) and National Academy of Science workshops have highlighted the critical role advanced research tools play in addressing scientific challenges relevant to biology, sustainable energy, and technologies that will fuel economic development without degrading our environment. Among the specific capability needs for advancing science and technology are tools that extract more detailed information in realistic environments (in situ or operando) at extreme conditions (pressure and temperature) and as a function of time (dynamic and time-dependent). One of the DOE workshops, Future Science Needs and Opportunities for Electron Scattering: Next Generation Instrumentation and Beyond, specifically addressed the importance of electron-based characterization methods for a wide range of energy-relevant Grand Scientific Challenges. Boosted by the electron optical advancement in the last decade, a diversity of in situ capabilities already is available in many laboratories. The obvious remaining major capability gap in electron microscopy is in the ability to make these direct in situ observations over a broad spectrum of fast (µs) to ultrafast (picosecond [ps] and faster) temporal regimes. In an effort to address current capability gaps, EMSL, the Environmental Molecular Sciences Laboratory, organized an Ultrafast Electron Microscopy Workshop, held June 14-15, 2011, with the primary goal to identify the scientific needs that could be met by creating a facility capable of a strongly improved time resolution with integrated in situ capabilities. The workshop brought together more than 40 leading scientists involved in applying and/or advancing electron microscopy to address important scientific problems of relevance to DOE’s research

  9. The materials physics companion

    CERN Document Server

    Fischer-Cripps, Anthony C

    2014-01-01

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

  10. Influence of frequency of the excitation magnetic field and material's electric conductivity on domain wall dynamics in ferromagnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Chávez-González, A.F. [Laboratorio de Evaluación No Destructiva Electromagnética (LENDE), ESIME-SEPI, Edif. Z-4, Instituto Politécnico Nacional, Zacatenco, México D.F., México (Mexico); Pérez-Benítez, J.A., E-mail: benitez_edl@yahoo.es [Laboratorio de Evaluación No Destructiva Electromagnética (LENDE), ESIME-SEPI, Edif. Z-4, Instituto Politécnico Nacional, Zacatenco, México D.F., México (Mexico); Espina-Hernández, J.H. [Laboratorio de Evaluación No Destructiva Electromagnética (LENDE), ESIME-SEPI, Edif. Z-4, Instituto Politécnico Nacional, Zacatenco, México D.F., México (Mexico); Grössinger, R. [Institute of Solid State Physics, Vienna University of Technology, Vienna (Austria); Hallen, J.M. [Departamento de Ingeniería Metalúrgica, ESIQIE, UPALM Edif. 7, Instituto Politécnico Nacional, Zacatenco, C.P. 07738, México D.F., México (Mexico)

    2016-03-01

    The present work analyzes the influence of electric conductivity on the Magnetic Barkhausen Noise (MBN) signal using a microscopic model which includes the influence of eddy currents. This model is also implemented to explain the dependence of MBN on the frequency of the applied magnetic field. The results presented in this work allow analyzing the influence of eddy currents on MBN signals for different values of the material's electric conductivity and for different frequencies of applied magnetic field. Additionally, the outcomes of this research can be used as a reference to differentiate the influence of eddy currents from that of second phase particles in the MBN signal, which has been reported in previous works. - Highlights: • Electromagnetic simulation of MBN with eddy currents and micro-magnetism. • Influence of applied field frequency on MBN is explained. • Influence of electric conductivity on MBN is analyzed. • Hysteresis losses in ferromagnetic materials is analyzed using the model.

  11. 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

    International Nuclear Information System (INIS)

    Fuse, Masaaki; Tsunemi, Kiyotaka

    2012-01-01

    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. -- Highlights: ► We model the life cycle flows for solder-containing metals in Japan. ► The Japanese shift to lead-free solders progresses rapidly for a decade. ► Substitution for lead in solders slows down during the late life cycle stages. ► The deceleration of substitution precludes a reduction in lead emissions to air.

  12. Collection and identification of human remains volatiles by non-contact, dynamic airflow sampling and SPME-GC/MS using various sorbent materials.

    Science.gov (United States)

    DeGreeff, Lauryn E; Furton, Kenneth G

    2011-09-01

    Human remains detection canines are used in locating deceased humans in diverse scenarios and environments based on odor produced during the decay process of the human body. It has been established that human remains detection canines are capable of locating human remains specifically, as opposed to living humans or animal remains, thus suggesting a difference in odor between the different sources. This work explores the collection and determination of such odors using a dynamic headspace concentration device. The airflow rate and three sorbent materials-Dukal cotton gauze, Johnson & Johnson cotton-blend gauze, and polyester material-used for odor collection were evaluated using standard compounds. It was determined that higher airflow rates and openly woven material, e.g., Dukal cotton gauze, yielded significantly less total volatile compounds due to compound breakthrough through the sorbent material. Collection from polymer- and cellulose-based materials demonstrated that the molecular backbone of the material is a factor in compound collection as well. Volatiles, including cyclic and straight-chain hydrocarbons, organic acids, sulfides, aldehydes, ketones, and alcohols, were collected from a population of 27 deceased bodies from two collection locations. The common compounds between the subjects were compared and the odor profiles were determined. These odor profiles were compared with those of animal remains and living human subjects collected in the same manner. Principal component analysis showed that the odor profiles of the three sample types were distinct.

  13. The Evaluation of Vehicle Mass Reduction and Material Choice in Life Cycle Assessments: Key Factors and Dynamic Industries

    Science.gov (United States)

    Developments in the realm of lightweight materials for automotive use continue to be announced by the industry and by academia. This session will provide new and updated information on new generation of materials. Additionally, this session will focus on the key topics involved i...

  14. Designing topological defects in 2D materials using scanning probe microscopy and a self-healing mechanism: a density functional-based molecular dynamics study

    Science.gov (United States)

    Popov, Igor; Đurišić, Ivana; Belić, Milivoj R.

    2017-12-01

    Engineering of materials at the atomic level is one of the most important aims of nanotechnology. The unprecedented ability of scanning probe microscopy to address individual atoms opened up the possibilities for nanomanipulation and nanolitography of surfaces and later on of two-dimensional materials. While the state-of-the-art scanning probe lithographic methods include, primarily, adsorption, desorption and repositioning of adatoms and molecules on substrates or tailoring nanoribbons by etching of trenches, the precise modification of the intrinsic atomic structure of materials is yet to be advanced. Here we introduce a new concept, scanning probe microscopy with a rotating tip, for engineering of the atomic structure of membranes based on two-dimensional materials. In order to indicate the viability of the concept, we present our theoretical research, which includes atomistic modeling, molecular dynamics simulations, Fourier analysis and electronic transport calculations. While stretching can be employed for fabrication of atomic chains only, our comprehensive molecular dynamics simulations indicate that nanomanipulation by scanning probe microscopy with a rotating tip is capable of assembling a wide range of topological defects in two-dimensional materials in a rather controllable and reproducible manner. We analyze two possibilities. In the first case the probe tip is retracted from the membrane while in the second case the tip is released beneath the membrane allowing graphene to freely relax and self-heal the pore made by the tip. The former approach with the tip rotation can be achieved experimentally by rotation of the sample, which is equivalent to rotation of the tip, whereas irradiation of the membrane by nanoclusters can be utilized for the latter approach. The latter one has the potential to yield a yet richer diversity of topological defects on account of a lesser determinacy. If successfully realized experimentally the concept proposed here could

  15. Modeling of light dynamic cone penetration test - Panda 3 ® in granular material by using 3D Discrete element method

    Science.gov (United States)

    Tran, Quoc Anh; Chevalier, Bastien; Benz, Miguel; Breul, Pierre; Gourvès, Roland

    2017-06-01

    The recent technological developments made on the light dynamic penetration test Panda 3 ® provide a dynamic load-penetration curve σp - sp for each impact. This curve is influenced by the mechanical and physical properties of the investigated granular media. In order to analyze and exploit the load-penetration curve, a numerical model of penetration test using 3D Discrete Element Method is proposed for reproducing tests in dynamic conditions in granular media. All parameters of impact used in this model have at first been calibrated by respecting mechanical and geometrical properties of the hammer and the rod. There is a good agreement between experimental results and the ones obtained from simulations in 2D or 3D. After creating a sample, we will simulate the Panda 3 ®. It is possible to measure directly the dynamic load-penetration curve occurring at the tip for each impact. Using the force and acceleration measured in the top part of the rod, it is possible to separate the incident and reflected waves and then calculate the tip's load-penetration curve. The load-penetration curve obtained is qualitatively similar with that obtained by experimental tests. In addition, the frequency analysis of the measured signals present also a good compliance with that measured in reality when the tip resistance is qualitatively similar.

  16. Modelling multiple cycles of static and dynamic recrystallisation using a fully implicit isotropic material model based on dislocation density

    Science.gov (United States)

    Jansen van Rensburg, Gerhardus J.; Kok, Schalk; Wilke, Daniel N.

    2018-03-01

    This paper presents the development and numerical implementation of a state variable based thermomechanical material model, intended for use within a fully implicit finite element formulation. Plastic hardening, thermal recovery and multiple cycles of recrystallisation can be tracked for single peak as well as multiple peak recrystallisation response. The numerical implementation of the state variable model extends on a J2 isotropic hypo-elastoplastic modelling framework. The complete numerical implementation is presented as an Abaqus UMAT and linked subroutines. Implementation is discussed with detailed explanation of the derivation and use of various sensitivities, internal state variable management and multiple recrystallisation cycle contributions. A flow chart explaining the proposed numerical implementation is provided as well as verification on the convergence of the material subroutine. The material model is characterised using two high temperature data sets for cobalt and copper. The results of finite element analyses using the material parameter values characterised on the copper data set are also presented.

  17. Analysis of Dynamic Fracture Parameters in Functionally Graded Material Plates with Cracks by Graded Finite Element Method and Virtual Crack Closure Technique

    Directory of Open Access Journals (Sweden)

    Li Ming Zhou

    2016-01-01

    Full Text Available Based on the finite element software ABAQUS and graded element method, we developed a dummy node fracture element, wrote the user subroutines UMAT and UEL, and solved the energy release rate component of functionally graded material (FGM plates with cracks. An interface element tailored for the virtual crack closure technique (VCCT was applied. Fixed cracks and moving cracks under dynamic loads were simulated. The results were compared to other VCCT-based analyses. With the implementation of a crack speed function within the element, it can be easily expanded to the cases of varying crack velocities, without convergence difficulty for all cases. Neither singular element nor collapsed element was required. Therefore, due to its simplicity, the VCCT interface element is a potential tool for engineers to conduct dynamic fracture analysis in conjunction with commercial finite element analysis codes.

  18. ThermoData Engine (TDE): Software Implementation of the Dynamic Data Evaluation Concept. 8. Properties of Material Streams and Solvent Design

    DEFF Research Database (Denmark)

    Diky, Vladimir; Chirico, Robert D.; Muzny, Chris D.

    2013-01-01

    ThermoData Engine (TDE) is the first full-scale software implementation of the dynamic data evaluation concept, as reported in this journal. The present paper describes the first application of this concept to the evaluation of thermophysical properties for material streams involving any number...... of chemical components with assessment of uncertainties. The method involves construction of Redlich-Kister type equations for individual properties (excess volume, thermal conductivity, viscosity, surface tension, and excess enthalpy) and activity-coefficient models for phase equilibrium properties (vapor...

  19. Development of in-situ observation system of dynamic contact interface between dies and materials during microforming operation

    Directory of Open Access Journals (Sweden)

    Shimizu Tetsuhide

    2015-01-01

    Full Text Available Application of diamond like carbon (DLC films are reported in several microforming processes, in view of its great tribological performance owe to the low friction and the high chemical stability. However, due to its high internal residual stress, the film properties with the low adhesion strength and the high wear rate under severe tribological conditions are still remain as technical issues. However, since the dynamic variation of the contact state cannot be observed during the forming operation, it is difficult to recognize the origin and the influential tribological factors of tool life for DLC coated microforming die. Therefore, the appropriate DLC film properties for the contact state in microforming operation have not been clarified. To observe the dynamic variation of the contact state during the microforming operation, present study developed a novel microforming die assembly installed the in-situ observation system with silica glass die and high speed recording camera. By using this system, the dynamic delamination behaviour of DLC films during the progressive micro-bending process was successfully demonstrated. The influential factors for the durability of DLC coated microdies were discussed.

  20. Dynamical correlation effects in a weakly correlated material: Inelastic x-ray scattering and photoemission spectra of beryllium

    Science.gov (United States)

    Seidu, Azimatu; Marini, Andrea; Gatti, Matteo

    2018-03-01

    Beryllium is a weakly correlated simple metal. Still we find that dynamical correlation effects, beyond the independent-particle picture, are necessary to successfully interpret the electronic spectra measured by inelastic x-ray scattering (IXS) and photoemission spectroscopies (PES). By combining ab initio time-dependent density-functional theory (TDDFT) and many-body Green's function theory in the G W approximation (G W A ), we calculate the dynamic structure factor, the quasiparticle (QP) properties and PES spectra of bulk Be. We show that band-structure effects (i.e., due to interaction with the crystal potential) and QP lifetimes (LT) are both needed in order to explain the origin of the measured double-peak features in the IXS spectra. A quantitative agreement with experiment is obtained only when LT are supplemented to the adiabatic local-density approximation (ALDA) of TDDFT. Besides the valence band, PES spectra display a satellite, a signature of dynamical correlation due to the coupling of QPs and plasmons, which we are able to reproduce thanks to the combination of the G W A for the self-energy with the cumulant expansion of the Green's function.

  1. Multi-scale multi-physics computational chemistry simulation based on ultra-accelerated quantum chemical molecular dynamics method for structural materials in boiling water reactor

    International Nuclear Information System (INIS)

    Miyamoto, Akira; Sato, Etsuko; Sato, Ryo; Inaba, Kenji; Hatakeyama, Nozomu

    2014-01-01

    In collaboration with experimental experts we have reported in the present conference (Hatakeyama, N. et al., “Experiment-integrated multi-scale, multi-physics computational chemistry simulation applied to corrosion behaviour of BWR structural materials”) the results of multi-scale multi-physics computational chemistry simulations applied to the corrosion behaviour of BWR structural materials. In macro-scale, a macroscopic simulator of anode polarization curve was developed to solve the spatially one-dimensional electrochemical equations on the material surface in continuum level in order to understand the corrosion behaviour of typical BWR structural material, SUS304. The experimental anode polarization behaviours of each pure metal were reproduced by fitting all the rates of electrochemical reactions and then the anode polarization curve of SUS304 was calculated by using the same parameters and found to reproduce the experimental behaviour successfully. In meso-scale, a kinetic Monte Carlo (KMC) simulator was applied to an actual-time simulation of the morphological corrosion behaviour under the influence of an applied voltage. In micro-scale, an ultra-accelerated quantum chemical molecular dynamics (UA-QCMD) code was applied to various metallic oxide surfaces of Fe 2 O 3 , Fe 3 O 4 , Cr 2 O 3 modelled as same as water molecules and dissolved metallic ions on the surfaces, then the dissolution and segregation behaviours were successfully simulated dynamically by using UA-QCMD. In this paper we describe details of the multi-scale, multi-physics computational chemistry method especially the UA-QCMD method. This method is approximately 10,000,000 times faster than conventional first-principles molecular dynamics methods based on density-functional theory (DFT), and the accuracy was also validated for various metals and metal oxides compared with DFT results. To assure multi-scale multi-physics computational chemistry simulation based on the UA-QCMD method for

  2. Pressure dynamics in the trays caused by differences of the various impression materials and thickness of the relief in the maxillary edentulous model.

    Science.gov (United States)

    Iwasaki, Masatoshi; Kawara, Misao; Inoue, Sayumi; Komiyama, Osamu; Iida, Takashi; Asano, Takashi

    2016-04-01

    The purpose of this study is to compare the pressure dynamics in the trays caused by differences in the various impression materials and in the thickness of the relief provided for the trays. In this study, two types of polyvinylsiloxane elastomers, one type of polyether elastomer and one type of alginate impression material were used. Pressure sensors were embedded at eight locations in a model of an edentulous maxilla, and used a simulation model covered with a pseudomucosa. For each impression material, the measurement was performed five times for each of the three types of trays, and the mean values were determined. Statistical analysis was carried out using one-way analysis of variance and the Tukey's HDS method, and the various pressure sensor values for each of the impression materials were compared 10s and 20s after the start of the measurement. Additionally, we compared differences among the three types of trays after 20s. The pressure values for sensors placed in the relief region tended to become uniform. Furthermore, we saw a tendency for the pressure to increase at the alveolar crests of the first molars on the left and right and at the posterior border of the palate, all of which support the denture, when relief was provided. The above results suggest that making the final impression for the denture using the selective pressure technique, with consideration given to the pressure dynamic, may lead to a good outcome in terms of preservation of the alveolar ridge. Copyright © 2015 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  3. [Theoretical studies of dynamics and correlations in heavy electron materials:]: Progress report, August 15, 1987-August 15, 1988

    International Nuclear Information System (INIS)

    1988-01-01

    This paper discusses progress in heavy electron research and high temperature superconductivity research. Particular topics discussed are: quadrupolar Kondo effect; coherence in the Anderson Lattice; Hall effect in heavy electron systems, suppression of supeconductivity by disorder in strongly correlated electronic materials; and charge transfer mechanisms for high temperature superconductivity

  4. Dramatic effect of pore size reduction on the dynamics of hydrogen adsorbed in metal–organic materials

    KAUST Repository

    Nugent, Patrick; Pham, Tony; McLaughlin, Keith; Georgiev, Peter A.; Lohstroh, Wiebke; Embs, Jan Peter; Zaworotko, Michael J.; Space, Brian; Eckert, Juergen

    2014-01-01

    -2-Cu-i is nearly two times higher than that for SIFSIX-2-Cu (8.6 vs. 4.6 kJ mol-1). The INS spectrum for H2 in SIFSIX-2-Cu-i is rather unique for a porous material, as only one broad peak appears at low energies near 6 meV, which simply increases

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

    International Nuclear Information System (INIS)

    Arai, Taketoshi

    1997-01-01

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

  6. Acquisition of Dynamic Mechanical Analyzer and Stress-Controlled Rheometer for the Mechanical Characterization of Advanced Materials

    Science.gov (United States)

    2017-06-27

    Current efforts aim to refine synthetic methods to achieve high molecular weight polymer and investigate mechanical properties. Figure 4 shows... available in the PCCL. For example, the Sumerlin group is attempting to characterize stimuli-responsive methacrylate networks of varying glass transition...over 100 researchers in advanced polymer materials. Within this, the Polymer Chemistry Characterization Laboratory (PCCL) is a user facility that

  7. High-resolution high-speed dynamic mechanical spectroscopy of cells and other soft materials with the help of atomic force microscopy.

    Science.gov (United States)

    Dokukin, M; Sokolov, I

    2015-07-28

    Dynamic mechanical spectroscopy (DMS), which allows measuring frequency-dependent viscoelastic properties, is important to study soft materials, tissues, biomaterials, polymers. However, the existing DMS techniques (nanoindentation) have limited resolution when used on soft materials, preventing them from being used to study mechanics at the nanoscale. The nanoindenters are not capable of measuring cells, nanointerfaces of composite materials. Here we present a highly accurate DMS modality, which is a combination of three different methods: quantitative nanoindentation (nanoDMA), gentle force and fast response of atomic force microscopy (AFM), and Fourier transform (FT) spectroscopy. This new spectroscopy (which we suggest to call FT-nanoDMA) is fast and sensitive enough to allow DMS imaging of nanointerfaces, single cells, while attaining about 100x improvements on polymers in both spatial (to 10-70 nm) and temporal resolution (to 0.7 s/pixel) compared to the current art. Multiple frequencies are measured simultaneously. The use of 10 frequencies are demonstrated here (up to 300 Hz which is a rather relevant range for biological materials and polymers, in both ambient conditions and liquid). The method is quantitatively verified on known polymers and demonstrated on cells and polymers blends. Analysis shows that FT-nanoDMA is highly quantitative. The FT-nanoDMA spectroscopy can easily be implemented in the existing AFMs.

  8. PIXE/RBS as a tool to study cementitious materials: Application to the dynamic leaching of concrete

    Energy Technology Data Exchange (ETDEWEB)

    Llorente, I., E-mail: irene@cenim.csic.e [Centro Nacional de Investigaciones Metalurgicas (CENIM-CSIC), Avda Gregorio del Amo, 8, 28040 Madrid (Spain); Castellote, M. [Instituto de Ciencias de la Construccion ' Eduardo Torroja' (IETcc-CSIC), Serrano Galvache, 4, 28033 Madrid (Spain); Gonzalez-Arrabal, R. [Parque Cientifico de Madrid, Campus de Cantoblanco, Einstein 13, 28049 Madrid (Spain); Ynsa, M.D.; Munoz-Martin, A. [Centro de Microanalisis de Materiales (CMAM), Universidad Autonoma de Madrid, Campus de Cantoblanco, 28049 Madrid (Spain); Viedma, P.G. de; Castillo, A.; Martinez, I.; Andrade, C. [Instituto de Ciencias de la Construccion ' Eduardo Torroja' (IETcc-CSIC), Serrano Galvache, 4, 28033 Madrid (Spain); Zuloaga, P.; Ordonez, M. [Empresa Nacional de Residuos Radiactivos, S.A. (ENRESA), Emilio Vargas, 7, 28043 Madrid (Spain)

    2009-12-15

    The suitability of the application of Ion Beam Analysis (IBA) techniques such as Particle Induced X-ray Emission spectrometry (PIXE) and Rutherford Backscattering Spectrometry (RBS) to elemental depth profiling in concrete is analysed, studying hardened samples of concrete prior to and after a dynamic leaching test. A calibration of the data has been done by comparing the results obtained by IBA techniques with those obtained by Chemical and Thermogravimetric Analysis (TG/DTA). From PIXE and RBS data relevant information about the migration of minor elements, within the concrete matrix after leaching is obtained.

  9. PIXE/RBS as a tool to study cementitious materials: Application to the dynamic leaching of concrete

    International Nuclear Information System (INIS)

    Llorente, I.; Castellote, M.; Gonzalez-Arrabal, R.; Ynsa, M.D.; Munoz-Martin, A.; Viedma, P.G. de; Castillo, A.; Martinez, I.; Andrade, C.; Zuloaga, P.; Ordonez, M.

    2009-01-01

    The suitability of the application of Ion Beam Analysis (IBA) techniques such as Particle Induced X-ray Emission spectrometry (PIXE) and Rutherford Backscattering Spectrometry (RBS) to elemental depth profiling in concrete is analysed, studying hardened samples of concrete prior to and after a dynamic leaching test. A calibration of the data has been done by comparing the results obtained by IBA techniques with those obtained by Chemical and Thermogravimetric Analysis (TG/DTA). From PIXE and RBS data relevant information about the migration of minor elements, within the concrete matrix after leaching is obtained.

  10. Molecular dynamics modeling of bonding two materials by atomic scale friction stir welding at different process parameters

    Science.gov (United States)

    Konovalenko S., Iv.; Psakhie, S. G.

    2017-12-01

    Using the molecular dynamics method, we simulated the atomic scale butt friction stir welding on two crystallites and varied the onset FSW tool plunge depth. The effects of the plunge depth value on the thermomechanical evolution of nanosized crystallites and mass transfer in the course of FSW have been studied. The increase of plunge depth values resulted in more intense heating and reducing the plasticized metal resistance to the tool movement. The mass transfer intensity was hardly dependent on the plunge depth value. The plunge depth was recommended to be used as a FSW process control parameter in addition to the commonly used ones.

  11. Understanding the interface between silicon-based materials and water: Molecular-dynamics exploration of infrared spectra

    Directory of Open Access Journals (Sweden)

    José A. Martinez-Gonzalez

    2017-11-01

    Full Text Available Molecular-dynamics simulations for silicon, hydrogen- and hydroxyl-terminated silicon in contact with liquid water, at 220 and 300 K, display water-density ‘ordering’ along the laboratory z-axis, emphasising the hydrophobicity of the different systems and the position of this first adsorbed layer. Density of states (DOS of the oxygen and proton velocity correlation functions (VACFs and infrared (IR spectra of the first monolayer of adsorbed water, calculated via Fourier transformation, indicate similarities to more confined, ice-like dynamical behaviour (redolent of ice. It was observed that good qualitative agreement is obtained between the DOS for this first layer in all systems. The DOS for the lower-frequency zone indicates that for the interface studied (i.e., the first layer near the surface, the water molecules try to organise in a similar form, and that this form is intermediate between liquid water and ice. For IR spectra, scrutiny of the position of the highest-intensity peaks for the stretching and bending bands indicate that such water molecules in the first solvating layer are organised in an intermediate fashion between ice and liquid water.

  12. Large eddy simulation/dynamic thickened flame modeling of a high Karlovitz number turbulent premixed jet flame (Supplementary material).

    Energy Technology Data Exchange (ETDEWEB)

    Han, Wang [Technical Univ. of Darmstadt (Germany); Wang, Haiou [Univ. of New South Wales, Sydney, NSW (Australia); Kuenne, Guido [Technical Univ. of Darmstadt (Germany); Hawkes, Evatt R. [Univ. of New South Wales, Sydney, NSW (Australia); Chen, Jacqueline H. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Janicka, Johannes [Technical Univ. of Darmstadt (Germany); Hasse, Christian [Technical Univ. of Darmstadt (Germany)

    2017-12-01

    This supplementary material complements the article and provides additional information to the chemical mechanism used in this work, boundary conditions for the LES con guration and table generation, comparisons of axial velocities, results from a LES/ nite-rate chemistry (FRC) approach, and results from the LES/DTF/SPF approach with a particular chemistry table that is generated using a single strained premixed amelet solution.

  13. Understanding the importance of the temperature dependence of viscosity on the crystallization dynamics in the Ge2Sb2Te5 phase-change material

    Science.gov (United States)

    Aladool, A.; Aziz, M. M.; Wright, C. D.

    2017-06-01

    The crystallization dynamics in the phase-change material Ge2Sb2Te5 is modelled using the more detailed Master equation method over a wide range of heating rates commensurate with published ultrafast calorimetry experiments. Through the attachment and detachment of monomers, the Master rate equation naturally traces nucleation and growth of crystallites with temperature history to calculate the transient distribution of cluster sizes in the material. Both the attachment and detachment rates in this theory are strong functions of viscosity, and thus, the value of viscosity and its dependence on temperature significantly affect the crystallization process. In this paper, we use the physically realistic Mauro-Yue-Ellison-Gupta-Allan viscosity model in the Master equation approach to study the role of the viscosity model parameters on the crystallization dynamics in Ge2Sb2Te5 under ramped annealing conditions with heating rates up to 4 × 104 K/s. Furthermore, due to the relatively low computational cost of the Master equation method compared to atomistic level computations, an iterative numerical approach was developed to fit theoretical Kissinger plots simulated with the Master equation system to experimental Kissinger plots from ultrafast calorimetry measurements at increasing heating rates. This provided a more rigorous method (incorporating both nucleation and growth processes) to extract the viscosity model parameters from the analysis of experimental data. The simulations and analysis revealed the strong coupling between the glass transition temperature and fragility index in the viscosity and crystallization models and highlighted the role of the dependence of the glass transition temperature on the heating rate for the accurate estimation of the fragility index of phase-change materials from the analysis of experimental measurements.

  14. An experimental and theoretical investigation of the liquefaction dynamics of a phase change material in a normal gravity environment

    Science.gov (United States)

    Bain, R. L.; Stermole, F. J.; Golden, J. O.

    1972-01-01

    Experimental and theoretical investigations were undertaken to determine the role of gravity-induced free convection upon the liquefaction dynamics of a cylindrical paraffin slab under normal gravity conditions. The experimental equipment consisted of a test cell, a fluid-loop heating system, and a multipoint recorder. The test chamber was annular in shape with an effective radius of 1.585 cm and a length of 5.08 cm. The heating chamber was a 1.906 cm diameter tube going through the center of the test chamber, and connected to the fluid loop heating system. All experimental runs were made with the longitudinal axis of the test cell in the vertical direction to insure that convection was not a function of the angular axis of the cell. Ten melting runs were made at various hot wall temperatures. Also, two pure conduction solidification runs were made to determine an experimental latent heat of fusion.

  15. Dynamic mechanical characterization with respect to temperature, humidity, frequency and strain in mPOFs made of different materials

    DEFF Research Database (Denmark)

    Leal-Junior, A.; Frizera, A.; Pontes, M. J.

    2018-01-01

    This paper presents a dynamic mechanical analysis (DMA) of polymer optical fibers (POFs) to obtain their Young modulus with respect to the variation of strain, temperature, humidity and frequency. The POFs tested are made of polymethyl methacrylate (PMMA), Topas grade 5013, Zeonex 480R...... and Polycarbonate (PC). In addition, a step index POF with a core composed of Topas 5013 and cladding of Zeonex 480R is also analyzed. Results show a tradeoffbetween the different fibers for different applications, where the Zeonex fiber shows the lowest Young modulus among the ones tested, which makes it suitable...... for high-sensitivity strain sensing applications. In addition, the fibers with Topas in their composition presented low temperature and humidity sensitivity, whereas PMMA fibers presented the highest Young modulus variation with different frequencies. The results presented here provide guidelines...

  16. Modelling for Near-Surface Transport Dynamics of Hydrogen of Plasma Facing Materials by use of Cellular Automaton

    International Nuclear Information System (INIS)

    Shimura, K.; Terai, T.; Yamawaki, M.

    2003-01-01

    In this study, the kinetics of desorption of adsorbed hydrogen from an ideal metallic surface is modelled in Cellular Automaton (CA). The modelling is achieved by downgrading the surface to one dimension. The model consists of two parts that are surface migration and desorption. The former is attained by randomly sorting the particles at each time, the latter is realised by modelling the thermally-activated process. For the verification of this model, thermal desorption is simulated then the comparison with the chemical kinetics is carried out. Excellent agreement is observed from the result. The results show that this model is reasonable to express the recombinative desorption of two chemisorbed adatoms. Though, the application of this model is limited to the second-order reaction case. But it can be believed that the groundwork of modelling the transport dynamics of hydrogen through the surface under complex conditions is established

  17. An experimental investigation of the early dynamic impact behaviour of textile armour systems: Decoupling material from system response

    Science.gov (United States)

    Cepus, Elvis

    This work focuses on the early impact response of textile armour systems. A relatively new data acquisition system, the Enhanced Laser Velocity Sensor (ELVS), was refined and used to generate a large database of results for a 5.57 mm diameter, 3 gram, non-deforming projectile impacting single-ply configurations of Ballistic Nylon, two weaves of Kevlar 129, and Zylon (PBO) over a range of velocities from 61 m/s to 248 m/s. In addition, one Kevlar 129 material was tested in configurations of 2, 3, 4, 8 and 16 plies over a range of strike velocities from 90 m/s to 481 m/s. ELVS results consisted of high-resolution timehistories of displacement, velocity and energy for each system tested. The strain wave velocity and ballistic performance of each system was also determined. Results taken from during the impact event were analysed up to just prior to the strain-wave rebounding from the boundary and returning to the impact point---effectively removing boundary influences. Regardless of system type, a constant rate of energy absorption within the pre-rebound timeframe was found to exist, which scales with the strike velocity to approximately the 8/3-power. Well-established single fibre theory was modified and applied to woven materials. It was assumed that three primary energy absorption mechanisms exist; elastic strain, in-plane kinetic and out-of-plane kinetic. This simple model yields the experimentally observed 8/3 exponent and parametrically predicts the difference between the different single-ply material systems, but underpredicts the observed behaviour by a factor of 2 and cannot address the performance reduction with increasing ply count. This combined experimental and analytical work confirms the long-held assumption that single fibre wave physics is applicable to multi-ply woven systems. More significantly, for the first time, it decouples material response from overall system response and provides the experimental tools and methodology required to analyse

  18. Development on analytical method of computational dynamic property and optimum design method of texture construction considering microscopic texture of the materials for nuclear powers

    International Nuclear Information System (INIS)

    Shiraishi, Haruki

    1997-01-01

    In structural design of the nuclear reactor core, He void boundary embrittlement used for a factor of determining using temperature limit of the structural materials is said to be formed by He void present at the crystal particles boundary. However, it has been not succeeded in quantitative estimation on ductility of the materials containing He voids formed on neutron radiation. In this paper, the results of qualitative analysis on effect of voids shapes (size and density) on the boundary He embrittlement were reported. Using two-dimensional elastoplastic finite element method, stress-strain curve of the materials containing voids at crystal boundary was analyzed. At that time, suppositions such as continuous body dynamics, Von Mises yield condition, n-power hardening rule, repeating boundary condition and so on were adopted. As a result, it was found that deformation type was divided to inter-particle deformation and boundary deformation types, and that so-called boundary He embrittlement was belonged to the latter. (G.K.)

  19. Source Material and Concentration of Wildfire-Produced Pyrogenic Carbon Influence Post-Fire Soil Nutrient Dynamics

    Directory of Open Access Journals (Sweden)

    Lucas A. Michelotti

    2015-04-01

    Full Text Available Pyrogenic carbon (PyC is produced by the thermal decomposition of organic matter in the absence of oxygen (O. PyC affects nutrient availability, may enhance post-fire nitrogen (N mineralization rates, and can be a significant carbon (C pool in fire-prone ecosystems. Our objectives were to characterize PyC produced by wildfires and examine the influence that contrasting types of PyC have on C and N mineralization rates. We determined C, N, O, and hydrogen (H concentrations and atomic ratios of charred bark (BK, charred pine cones (PC, and charred woody debris (WD using elemental analysis. We also incubated soil amended with BK, PC, and WD at two concentrations for 60 days to measure C and N mineralization rates. PC had greater H/C and O/C ratios than BK and WD, suggesting that PC may have a lesser aromatic component than BK and WD. C and N mineralization rates decreased with increasing PyC concentrations, and control samples produced more CO2 than soils amended with PyC. Soils with PC produced greater CO2 and had lower N mineralization rates than soils with BK or WD. These results demonstrate that PyC type and concentration have potential to impact nutrient dynamics and C flux to the atmosphere in post-fire forest soils.

  20. Molecular dynamics simulations of shock compressed heterogeneous materials. II. The graphite/diamond transition case for astrophysics applications

    Science.gov (United States)

    Pineau, N.; Soulard, L.; Colombet, L.; Carrard, T.; Pellé, A.; Gillet, Ph.; Clérouin, J.

    2015-03-01

    We present a series of molecular dynamics simulations of the shock compression of copper matrices containing a single graphite inclusion: these model systems can be related to some specific carbon-rich rocks which, after a meteoritic impact, are found to contain small fractions of nanodiamonds embedded in graphite in the vicinity of high impedance minerals. We show that the graphite to diamond transformation occurs readily for nanometer-sized graphite inclusions, via a shock accumulation process, provided the pressure threshold of the bulk graphite/diamond transition is overcome, independently of the shape or size of the inclusion. Although high diamond yields (˜80%) are found after a few picoseconds in all cases, the transition is non-isotropic and depends substantially on the relative orientation of the graphite stack with respect to the shock propagation, leading to distinct nucleation processes and size-distributions of the diamond grains. A substantial regraphitization process occurs upon release and only inclusions with favorable orientations likely lead to the preservation of a fraction of this diamond phase. These results agree qualitatively well with the recent experimental observations of meteoritic impact samples.

  1. Combining nanocalorimetry and dynamic transmission electron microscopy for in situ characterization of materials processes under rapid heating and cooling

    Energy Technology Data Exchange (ETDEWEB)

    Grapes, Michael D., E-mail: mgrapes1@jhu.edu [Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); LaGrange, Thomas; Reed, Bryan W.; Campbell, Geoffrey H. [Condensed Matter and Materials Division, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Friedman, Lawrence H.; LaVan, David A., E-mail: david.lavan@nist.gov [Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Weihs, Timothy P., E-mail: weihs@jhu.edu [Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States)

    2014-08-15

    Nanocalorimetry is a chip-based thermal analysis technique capable of analyzing endothermic and exothermic reactions at very high heating and cooling rates. Here, we couple a nanocalorimeter with an extremely fast in situ microstructural characterization tool to identify the physical origin of rapid enthalpic signals. More specifically, we describe the development of a system to enable in situ nanocalorimetry experiments in the dynamic transmission electron microscope (DTEM), a time-resolved TEM capable of generating images and electron diffraction patterns with exposure times of 30 ns–500 ns. The full experimental system consists of a modified nanocalorimeter sensor, a custom-built in situ nanocalorimetry holder, a data acquisition system, and the DTEM itself, and is capable of thermodynamic and microstructural characterization of reactions over a range of heating rates (10{sup 2} K/s–10{sup 5} K/s) accessible by conventional (DC) nanocalorimetry. To establish its ability to capture synchronized calorimetric and microstructural data during rapid transformations, this work describes measurements on the melting of an aluminum thin film. We were able to identify the phase transformation in both the nanocalorimetry traces and in electron diffraction patterns taken by the DTEM. Potential applications for the newly developed system are described and future system improvements are discussed.

  2. Ultrafast Excited-State Dynamics of Diketopyrrolopyrrole (DPP)-Based Materials: Static versus Diffusion-Controlled Electron Transfer Process

    KAUST Repository

    Alsulami, Qana

    2015-06-25

    Singlet-to-triplet intersystem crossing (ISC) and photoinduced electron transfer (PET) of platinum(II) containing diketopyrrolopyrrole (DPP) oligomer in the absence and presence of strong electron-acceptor tetracyanoethylene (TCNE) were investigated using femtosecond and nanosecond transient absorption spectroscopy with broadband capabilities. The role of platinum(II) incorporation in those photophysical properties was evaluated by comparing the excited-state dynamics of DPP with and without the metal centers. The steady-state measurements reveal that platinum(II) incorporation facilitates dramatically the interactions between DPP-Pt(acac) and TCNE, resulting in charge transfer (CT) complex formation. The transient absorption spectra in the absence of TCNE reveal ultrafast ISC of DPP-Pt(acac) followed by their long-lived triplet state. In the presence of TCNE, PET from the excited DPP-Pt(acac) and DPP to TCNE, forming the radical ion pairs. The ultrafast PET which occurs statically from DPP-Pt(acac) to TCNE in picosecond regime, is much faster than that from DPP to TCNE (nanosecond time scale) which is diffusion-controlled process, providing clear evidence that PET rate is eventually controlled by the platinum(II) incorporation.

  3. Ultrafast Excited-State Dynamics of Diketopyrrolopyrrole (DPP)-Based Materials: Static versus Diffusion-Controlled Electron Transfer Process

    KAUST Repository

    Alsulami, Qana; Aly, Shawkat Mohammede; Goswami, Subhadip; Alarousu, Erkki; Usman, Anwar; Schanze, Kirk S.; Mohammed, Omar F.

    2015-01-01

    Singlet-to-triplet intersystem crossing (ISC) and photoinduced electron transfer (PET) of platinum(II) containing diketopyrrolopyrrole (DPP) oligomer in the absence and presence of strong electron-acceptor tetracyanoethylene (TCNE) were investigated using femtosecond and nanosecond transient absorption spectroscopy with broadband capabilities. The role of platinum(II) incorporation in those photophysical properties was evaluated by comparing the excited-state dynamics of DPP with and without the metal centers. The steady-state measurements reveal that platinum(II) incorporation facilitates dramatically the interactions between DPP-Pt(acac) and TCNE, resulting in charge transfer (CT) complex formation. The transient absorption spectra in the absence of TCNE reveal ultrafast ISC of DPP-Pt(acac) followed by their long-lived triplet state. In the presence of TCNE, PET from the excited DPP-Pt(acac) and DPP to TCNE, forming the radical ion pairs. The ultrafast PET which occurs statically from DPP-Pt(acac) to TCNE in picosecond regime, is much faster than that from DPP to TCNE (nanosecond time scale) which is diffusion-controlled process, providing clear evidence that PET rate is eventually controlled by the platinum(II) incorporation.

  4. The influence of microstructure on charge separation dynamics in organic bulk heterojunction materials for solar cell applications

    KAUST Repository

    Scarongella, Mariateresa; Paraecattil, Arun Aby; Buchaca-Domingo, Ester; Douglas, Jessica D.; Beaupré , Serge; McCarthy-Ward, Thomas; Heeney, Martin J.; Moser, Jacques Edouard; Leclerc, Mario; Frechet, Jean; Stingelin, Natalie; Banerji, Natalie

    2014-01-01

    Light-induced charge formation is essential for the generation of photocurrent in organic solar cells. In order to gain a better understanding of this complex process, we have investigated the femtosecond dynamics of charge separation upon selective excitation of either the fullerene or the polymer in different bulk heterojunction blends with well-characterized microstructure. Blends of the pBTTT and PBDTTPD polymers with PCBM gave us access to three different scenarios: either a single intermixed phase, an intermixed phase with additional pure PCBM clusters, or a three-phase microstructure of pure polymer aggregates, pure fullerene clusters and intermixed regions. We found that ultrafast charge separation (by electron or hole transfer) occurs predominantly in intermixed regions, while charges are generated more slowly from excitons in pure domains that require diffusion to a charge generation site. The pure domains are helpful to prevent geminate charge recombination, but they must be sufficiently small not to become exciton traps. By varying the polymer packing, backbone planarity and chain length, we have shown that exciton diffusion out of small polymer aggregates in the highly efficient PBDTTPD:PCBM blend occurs within the same chain and is helped by delocalization. This journal is © the Partner Organisations 2014.

  5. Flight-vehicle materials, structures, and dynamics - Assessment and future directions. Vol. 3 - Ceramics and ceramic-matrix composites

    Science.gov (United States)

    Levine, Stanley R. (Editor)

    1992-01-01

    The present volume discusses ceramics and ceramic-matrix composites in prospective aerospace systems, monolithic ceramics, transformation-toughened and whisker-reinforced ceramic composites, glass-ceramic matrix composites, reaction-bonded Si3N4 and SiC composites, and chemical vapor-infiltrated composites. Also discussed are the sol-gel-processing of ceramic composites, the fabrication and properties of fiber-reinforced ceramic composites with directed metal oxidation, the fracture behavior of ceramic-matrix composites (CMCs), the fatigue of fiber-reinforced CMCs, creep and rupture of CMCs, structural design methodologies for ceramic-based materials systems, the joining of ceramics and CMCs, and carbon-carbon composites.

  6. Energy dissipation effects on imaging of soft materials by dynamic atomic force microscopy: A DNA-chip study

    Energy Technology Data Exchange (ETDEWEB)

    Phaner-Goutorbe, M., E-mail: magali.phaner@ec-lyon.fr [Université de Lyon, Institut des Nanotechnologies de Lyon (INL) UMR CNRS 5270, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, 69134 Ecully (France); Iazykov, M. [Université de Lyon, laboratoire de Physique, Ecole Normale Supérieure de Lyon, 46 allée d' Italie 69364 Lyon cedex 07 (France); Villey, R. [Université de Lyon, Institut des Nanotechnologies de Lyon (INL) UMR CNRS 5270, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, 69134 Ecully (France); Université de Lyon, laboratoire de Physique de la Matière Condensée et Nanostructures, Université Claude Bernard Lyon 1, Domaine Scientifique de la Doua, Bâtiment Léon Brillouin 43 boulevard du 11 Novembre 1918, F 69622 Villeurbanne (France); Sicard, D.; Robach, Y. [Université de Lyon, Institut des Nanotechnologies de Lyon (INL) UMR CNRS 5270, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, 69134 Ecully (France)

    2013-05-01

    Using amplitude-mode AFM (AM-AFM), we have obtained valuable information during these recent years through the study of amplitude and phase shift dependence on tip–sample separation, leading to a comprehensive understanding of the interaction processes. Two imaging regimes, attractive and repulsive, have been identified and a relationship between phase and dissipative energy was established, providing information on observed material properties. Most of the previous studies have concerned model systems: either hard or soft materials. In this paper, we present the analysis of a mixed system of soft structures on a hard substrate. This is a DNA chip for biological applications consisting of oligonucleotides covalently linked by a layer of silane to a silicon substrate. A detailed study of amplitude-phase curves as a function of the tip–sample separation allowed us to define the best experimental conditions to obtain specific information: we got reliable conditions to minimize noise during topographic imaging and an understanding of the processes of energy dissipation involved in the DNA breaking for DNA arrays. By calculating the energy dissipated as a function of the amplitude of oscillation, we have demonstrated a transition from an energy dissipation process governed by localized viscoelastic interactions (due to the soft layer) to a process governed by extended irreversible deformations (due to the hard substrate). Highlights: ► Amplitude mode AFM analysis of a DNA array is presented. ► Reliable conditions for noise minimization on topographic images are presented. ► Phase, amplitude vs distance curves are analyzed for different setpoint amplitudes. ► Energy dissipation processes are described from viscoelasticity to DNA breaking.

  7. Molecular-wire behavior of OLED materials: exciton dynamics in multichromophoric Alq3-oligofluorene-Pt(II)porphyrin triads.

    Science.gov (United States)

    Montes, Victor A; Pérez-Bolívar, César; Agarwal, Neeraj; Shinar, Joseph; Anzenbacher, Pavel

    2006-09-27

    Donor-bridge-acceptor triads consisting of the Alq3 complex, oligofluorene bridge, and PtII tetraphenylporphyrin (PtTPP) were synthesized. The triads were designed to study the energy level/distance-dependence in energy transfer both in a solution and in solid state. The materials show effective singlet transfer from the Alq3-fluorene fluorophore to the porphyrin, while the triplet energy transfer, owing to the shorter delocalization of triplet excitons, appears to take place via a triplet energy cascade. Using femtosecond transient spectroscopy, the rate of the singlet-singlet energy transfer was determined. The exponential dependence of the donor-acceptor distance and the respective energy transfer rates of 7.1 x 1010 to 1.0 x 109 s-1 with the attenuation factor â of 0.21 +/- 0.02 A-1 suggest that the energy transfer proceeds via a mixed incohererent wire/superexchange mechanism. In the OLEDs fabricated using the Alq3-oligofluorene-PtTPP triads with better triplet level alignment, the order of a magnitude increase in efficacy appears to be due to facile triplet energy transfer. The devices, where the triplet-triplet energy transfer is of paramount importance, showed high color purity emission (CIE X,Y: 0.706, 0.277), which is almost identical to the emission from thin films. Most importantly, we believe that the design principles demonstrated above are general and may be used to prepare OLED materials with enhanced quantum efficacy at lowered operational potentials, being crucial for improved lifespan of OLEDs.

  8. Unconventional spin dynamics in the honeycomb-lattice material α -RuCl3 : High-field electron spin resonance studies

    Science.gov (United States)

    Ponomaryov, A. N.; Schulze, E.; Wosnitza, J.; Lampen-Kelley, P.; Banerjee, A.; Yan, J.-Q.; Bridges, C. A.; Mandrus, D. G.; Nagler, S. E.; Kolezhuk, A. K.; Zvyagin, S. A.

    2017-12-01

    We present high-field electron spin resonance (ESR) studies of the honeycomb-lattice material α -RuCl3 , a prime candidate to exhibit Kitaev physics. Two modes of antiferromagnetic resonance were detected in the zigzag ordered phase, with magnetic field applied in the a b plane. A very rich excitation spectrum was observed in the field-induced quantum paramagnetic phase. The obtained data are compared with the results of recent numerical calculations, strongly suggesting a very unconventional multiparticle character of the spin dynamics in α -RuCl3 . The frequency-field diagram of the lowest-energy ESR mode is found consistent with the behavior of the field-induced energy gap, revealed by thermodynamic measurements.

  9. A comparative study of composting the solid fraction of dairy manure with or without bulking material: Performance and microbial community dynamics.

    Science.gov (United States)

    Zhong, Xiao-Zhong; Ma, Shi-Chun; Wang, Shi-Peng; Wang, Ting-Ting; Sun, Zhao-Yong; Tang, Yue-Qin; Deng, Yu; Kida, Kenji

    2018-01-01

    The present study compared the development of various physicochemical properties and the composition of microbial communities involved in the composting process in the solid fraction of dairy manure (SFDM) with a sawdust-regulated SFDM (RDM). The changes in several primary physicochemical properties were similar in the two composting processes, and both resulted in mature end-products within 48days. The bacterial communities in both composting processes primarily comprised Proteobacteria and Bacteroidetes. Firmicutes were predominant in the thermophilic phase, whereas Chloroflexi, Planctomycetes, and Nitrospirae were more abundant in the final mature phase. Furthermore, the succession of bacteria in both groups proceeded in a similar pattern, suggesting that the effects of the bulking material on bacterial dynamics were minor. These results demonstrate the feasibility of composting using only the SFDM, reflected by the evolution of physicochemical properties and the microbial communities involved in the composting process. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Dynamics of deposited fly-ash and fine grained magnetite in sandy material of different porosity (column experiments)

    Science.gov (United States)

    Kapicka, Ales; Kodesova, Radka; Petrovsky, Eduard; Grison, Hana

    2010-05-01

    material. In medium and fine sand the contaminants moved only to the depths of several cm due to the pore-space blocking and water flow decrease. Fine-grained magnetite shows different behavior. Position of peaks value is more or less stable and maximum depth of penetration is only a few cm in all cases. Higher grain size value is probably reason for higher stability of magnetite. Moreover, magnetic interaction between grains increase "effective" grain size value and restricts transport in material with given porosity. This research is supported by the Grant Agency ASCR under grant IAA300120701

  11. The mechanical properties of fluoride salts at elevated temperatures. [candidate thermal energy storage materials for solar dynamic systems

    Science.gov (United States)

    Raj, S. V.; Whittenberger, J. D.

    1989-01-01

    The deformation behavior of CaF2 and LiF single crystals compressed in the 111 and the 100 line directions, respectively, are compared with the mechanical properties of polycrystalline LiF-22 (mol pct) CaF2 eutectic mixture in the temperature range 300 to 1275 K for strain rates varying between 7 x 10 to the -7th and 0.2/s. The true stress-strain curves for the single crystals were found to exhibit three stages in an intermediate range of temperatures and strain rates, whereas those for the eutectic showed negative work-hardening rates after a maximum stress. The true stress-strain rate data for CaF2 and LiF-22 CaF2 could be represented by a power-law relation with the strain rate sensitivities lying between 0.05 and 0.2 for both materials. A similar relation was found to be unsatisfactory in the case of LiF.

  12. Interplay between spatially explicit sediment sourcing, hierarchical river-network structure, and in-channel bed material sediment transport and storage dynamics

    Science.gov (United States)

    Czuba, Jonathan A.; Foufoula-Georgiou, Efi; Gran, Karen B.; Belmont, Patrick; Wilcock, Peter R.

    2017-05-01

    Understanding how sediment moves along source to sink pathways through watersheds—from hillslopes to channels and in and out of floodplains—is a fundamental problem in geomorphology. We contribute to advancing this understanding by modeling the transport and in-channel storage dynamics of bed material sediment on a river network over a 600 year time period. Specifically, we present spatiotemporal changes in bed sediment thickness along an entire river network to elucidate how river networks organize and process sediment supply. We apply our model to sand transport in the agricultural Greater Blue Earth River Basin in Minnesota. By casting the arrival of sediment to links of the network as a Poisson process, we derive analytically (under supply-limited conditions) the time-averaged probability distribution function of bed sediment thickness for each link of the river network for any spatial distribution of inputs. Under transport-limited conditions, the analytical assumptions of the Poisson arrival process are violated (due to in-channel storage dynamics) where we find large fluctuations and periodicity in the time series of bed sediment thickness. The time series of bed sediment thickness is the result of dynamics on a network in propagating, altering, and amalgamating sediment inputs in sometimes unexpected ways. One key insight gleaned from the model is that there can be a small fraction of reaches with relatively low-transport capacity within a nonequilibrium river network acting as "bottlenecks" that control sediment to downstream reaches, whereby fluctuations in bed elevation can dissociate from signals in sediment supply.

  13. A molecular dynamics investigation into the mechanisms of subsurface damage and material removal of monocrystalline copper subjected to nanoscale high speed grinding

    International Nuclear Information System (INIS)

    Li, Jia; Fang, Qihong; Liu, Youwen; Zhang, Liangchi

    2014-01-01

    This paper investigates the mechanisms of subsurface damage and material removal of monocrystalline copper when it is under a nanoscale high speed grinding of a diamond tip. The analysis was carried out with the aid of three-dimensional molecular dynamics simulations. The key factors that would influence the deformation of the material were carefully explored by analyzing the chip, dislocation movement, and workpiece deformation, which include grinding speed, depth of cut, grid tip radius, crystal orientation and machining angle of copper. An analytical model was also established to predict the emission of partial dislocations during the nanoscale high speed grinding. The investigation showed that a higher grinding velocity, a larger tip radius or a larger depth of cut would result in a larger chipping volume and a greater temperature rise in the copper workpiece. A lower grinding velocity would produce more intrinsic stacking faults. It was also found that the transition of deformation mechanisms depends on the competition between the dislocations and deformation twinning. There is a critical machining angle, at which a higher velocity, a smaller tip radius, or a smaller depth of cut will reduce the subsurface damage and improve the smoothness of a ground surface. The established analytical model showed that the Shockley dislocation emission is most likely to occur with the crystal orientations of (0 0 1)[1 0 0] at 45° angle.

  14. Differential dynamic microscopy microrheology of soft materials: A tracking-free determination of the frequency-dependent loss and storage moduli

    Science.gov (United States)

    Edera, Paolo; Bergamini, Davide; Trappe, Véronique; Giavazzi, Fabio; Cerbino, Roberto

    2017-12-01

    Particle-tracking microrheology (PT-μ r ) exploits the thermal motion of embedded particles to probe the local mechanical properties of soft materials. Despite its appealing conceptual simplicity, PT-μ r requires calibration procedures and operating assumptions that constitute a practical barrier to its wider application. Here we demonstrate differential dynamic microscopy microrheology (DDM-μ r ), a tracking-free approach based on the multiscale, temporal correlation study of the image intensity fluctuations that are observed in microscopy experiments as a consequence of the translational and rotational motion of the tracers. We show that the mechanical moduli of an arbitrary sample are determined correctly over a wide frequency range provided that the standard DDM analysis is reinforced with an iterative, self-consistent procedure that fully exploits the multiscale information made available by DDM. Our approach to DDM-μ r does not require any prior calibration, is in agreement with both traditional rheology and diffusing wave spectroscopy microrheology, and works in conditions where PT-μ r fails, providing thus an operationally simple, calibration-free probe of soft materials.

  15. Investigation of the fluid flow dynamic parameters for Newtonian and non-Newtonian materials: an approach to understanding the fluid flow-like structures within fault zones

    Science.gov (United States)

    Tanaka, H.; Shiomi, Y.; Ma, K.-F.

    2017-11-01

    To understand the fault zone fluid flow-like structure, namely the ductile deformation structure, often observed in the geological field (e.g., Ramsay and Huber The techniques of modern structure geology, vol. 1: strain analysis, Academia Press, London, 1983; Hobbs and Ord Structure geology: the mechanics of deforming metamorphic rocks, Vol. I: principles, Elsevier, Amsterdam, 2015), we applied a theoretical approach to estimate the rate of deformation, the shear stress and the time to form a streak-line pattern in the boundary layer of viscous fluids. We model the dynamics of streak lines in laminar boundary layers for Newtonian and pseudoplastic fluids and compare the results to those obtained via laboratory experiments. The structure of deformed streak lines obtained using our model is consistent with experimental observations, indicating that our model is appropriate for understanding the shear rate, flow time and shear stress based on the profile of deformed streak lines in the boundary layer in Newtonian and pseudoplastic viscous materials. This study improves our understanding of the transportation processes in fluids and of the transformation processes in fluid-like materials. Further application of this model could facilitate understanding the shear stress and time history of the fluid flow-like structure of fault zones observed in the field.[Figure not available: see fulltext.

  16. Consequences of Molecular-Scale Non-Equilibrium Activity on the Dynamics and Mechanics of Self-Assembled Actin-Based Structures and Materials

    Science.gov (United States)

    Marshall Mccall, Patrick

    Living cells are hierarchically self-organized forms of active soft matter: molecules on the nanometer scale form functional structures and organelles on the micron scale, which then compose cells on the scale of 10s of microns. While the biological functions of intracellular organelles are defined by the composition and properties of the structures themselves, how those bulk properties emerge from the properties and interactions of individual molecules remains poorly understood. Actin, a globular protein which self-assembles into dynamic semi-flexible polymers, is the basic structural material of cells and the major component of many functional organelles. In this thesis, I have used purified actin as a model system to explore the interplay between molecular-scale dynamics and organelle-scale functionality, with particular focus on the role of molecular-scale non-equilibrium activity. One of the most canonical forms of molecular-scale non-equilibrium activity is that of mechanoenzymes, also called motor proteins. These proteins utilized the free energy liberated by hydrolysis of ATP to perform mechanical work, thereby introducing non-equilibrium "active" stresses on the molecular scale. Combining experiments with mathematical modeling, we demonstrate in this thesis that non-equilibrium motor activity is sufficient to drive self-organization and pattern formation of the multimeric actin-binding motor protein Myosin II on 1D reconstituted actomyosin bundles. Like myosin, actin is itself an ATPase. However, nono-equilibrium ATP hydrolysis on actin is known to regulate the stability and assembly kinetics of actin filaments rather than generate active stresses per se. At the level of single actin filaments, the inhomogeneous nucleotide composition generated along the filament length by hydrolysis directs binding of regulatory proteins like cofilin, which mediate filament disassembly and thereby accelerate actin filament turnover. The concequences of this non

  17. Conceptual design of a 10^{13}-W pulsed-power accelerator for megajoule-class dynamic-material-physics experiments

    Directory of Open Access Journals (Sweden)

    W. A. Stygar

    2016-07-01

    Full Text Available We have developed a conceptual design of a next-generation pulsed-power accelerator that is optimized for megajoule-class dynamic-material-physics experiments. Sufficient electrical energy is delivered by the accelerator to a physics load to achieve—within centimeter-scale samples—material pressures as high as 1 TPa. The accelerator design is based on an architecture that is founded on three concepts: single-stage electrical-pulse compression, impedance matching, and transit-time-isolated drive circuits. The prime power source of the accelerator consists of 600 independent impedance-matched Marx generators. Each Marx comprises eight 5.8-GW bricks connected electrically in series, and generates a 100-ns 46-GW electrical-power pulse. A 450-ns-long water-insulated coaxial-transmission-line impedance transformer transports the power generated by each Marx to a system of twelve 2.5-m-radius water-insulated conical transmission lines. The conical lines are connected electrically in parallel at a 66-cm radius by a water-insulated 45-post sextuple-post-hole convolute. The convolute sums the electrical currents at the outputs of the conical lines, and delivers the combined current to a single solid-dielectric-insulated radial transmission line. The radial line in turn transmits the combined current to the load. Since much of the accelerator is water insulated, we refer to it as Neptune. Neptune is 40 m in diameter, stores 4.8 MJ of electrical energy in its Marx capacitors, and generates 28 TW of peak electrical power. Since the Marxes are transit-time isolated from each other for 900 ns, they can be triggered at different times to construct–over an interval as long as 1  μs–the specific load-current time history required for a given experiment. Neptune delivers 1 MJ and 20 MA in a 380-ns current pulse to an 18-mΩ load; hence Neptune is a megajoule-class 20-MA arbitrary waveform generator. Neptune will allow the international

  18. Material Programming

    DEFF Research Database (Denmark)

    Vallgårda, Anna; Boer, Laurens; Tsaknaki, Vasiliki

    2017-01-01

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

  19. Dynamical systems

    CERN Document Server

    Sternberg, Shlomo

    2010-01-01

    Celebrated mathematician Shlomo Sternberg, a pioneer in the field of dynamical systems, created this modern one-semester introduction to the subject for his classes at Harvard University. Its wide-ranging treatment covers one-dimensional dynamics, differential equations, random walks, iterated function systems, symbolic dynamics, and Markov chains. Supplementary materials offer a variety of online components, including PowerPoint lecture slides for professors and MATLAB exercises.""Even though there are many dynamical systems books on the market, this book is bound to become a classic. The the

  20. Effects of zinc supplementation and zinc chelation on in vitro β-cell function in INS-1E cells

    DEFF Research Database (Denmark)

    Nygaard, Sanne Bjørn; Larsen, Agnete; Knuhtsen, Astrid

    2014-01-01

    BACKGROUND: Zinc is essential for the activities of pancreatic β-cells, especially insulin storage and secretion. Insulin secretion leads to co-release of zinc which contributes to the paracrine communication in the pancreatic islets. Zinc-transporting proteins (zinc-regulated transporter, iron......-regulated transporter-like proteins [ZIPs] and zinc transporters [ZnTs]) and metal-buffering proteins (metallothioneins, MTs) tightly regulate intracellular zinc homeostasis. The present study investigated how modulation of cellular zinc availability affects β-cell function using INS-1E cells. RESULTS: Using INS-1E...... cells, we found that zinc supplementation and zinc chelation had significant effects on insulin content and insulin secretion. Supplemental zinc within the physiological concentration range induced insulin secretion. Insulin content was reduced by zinc chelation with N,N,N',N-tektrakis(2-pyridylmethyl...

  1. How material contrast around subduction faults may control coseismic slip and rupture dynamics: tsunami applications for the case study of Tohoku

    Science.gov (United States)

    Scala, Antonio; Murphy, Shane; Romano, Fabrizio; Lorito, Stefano; Festa, Gaetano; Volpe, Manuela; Piatanesi, Alessio

    2017-04-01

    Recent megathrust tsunamigenic events, e.g. Maule 2010 (M8.8) and Tohoku 2011 (M9.0), generated huge tsunami waves as a consequence of high slip in the shallow part of the respective subduction zone. Other events, (e.g. the recent Mentawai 2010, M7.8, or the historical Meiji 1896, M8.2), referred to as tsunami earthquakes, produced unexpectedly large tsunami waves, probably due to large slip at shallow depth over longer rupture durations compared to deeper thrust events. Subduction zone earthquakes originate and propagate along bimaterial interfaces separating materials having different elastic properties, e.g. continental and oceanic crust, a stiffer deep mantle wedge, shallow compliant accretionary prism etc. Bimaterial interfaces have been showed, through observations (seismological and laboratory) and theoretical studies, to affect the rupture: introducing a preferred rupture direction as well as asymmetric rupture velocities and shear stress redistributions. Such features are predominantly due to the break of symmetry between the two sides of the interface in turn ascribable to the complex coupling between the frictional interfacial sliding and the slip-induced normal stress perturbations. In order to examine the influence of material contrast on a fault plane on the seismic source and tsunami waves, we modelled a Tohoku-like subduction zone to perform a large number of 2D along-dip rupture dynamics simulations in the framework of linear slip weakening both for homogeneous and bimaterial fault. In this latter model, the rupture acts as the interface between the subducting oceanic crust and the overriding layers (accretionary prism, continental crust and mantle wedge), varying the position of the shear stress asperity acting as nucleation patch. Initial results reveal that ruptures in homogeneous media produce earthquakes with large slip at depth compared to the case where bi-material interface is included. However the opposite occurs for events nucleating at

  2. Material analyses of foam-based SiC FCI after dynamic testing in PbLi in MaPLE loop at UCLA

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Maria, E-mail: maria.gonzalez@ciemat.es [LNF-CIEMAT, Avda Complutense, 40, 28040 Madrid (Spain); Rapisarda, David; Ibarra, Angel [LNF-CIEMAT, Avda Complutense, 40, 28040 Madrid (Spain); Courtessole, Cyril; Smolentsev, Sergey; Abdou, Mohamed [Fusion Science and Technology Center, UCLA (United States)

    2016-11-01

    Highlights: • Samples from foam-based SiC FCI were analyzed by looking at their SEM microstructure and elemental composition. • After finishing dynamic experiments in the flowing hot PbLi, the liquid metal ingress has been confirmed due to infiltration through local defects in the protective inner CVD layer. • No direct evidences of corrosion/erosion were observed; these defects could be related to the manufacturing process. - Abstract: Foam-based SiC flow channel inserts (FCIs) developed and manufactured by Ultramet, USA are currently under testing in the flowing hot lead-lithium (PbLi) alloy in the MaPLE loop at UCLA to address chemical/physical compatibility and to access the MHD pressure drop reduction. UCLA has finished the first experimental series, where a single uninterrupted long-term (∼6500 h) test was performed on a 30-cm FCI segment in a magnetic field up to 1.8 T at the temperature of 300 °C and maximum flow velocities of ∼ 15 cm/s. After finishing the experiments, the FCI sample was extracted from the host stainless steel duct and cut into slices. Few of them have been analyzed at CIEMAT as a part of the joint collaborative effort on the development of the DCLL blanket concept in the EU and the US. The initial inspection of the slices using optical microscopic analysis at UCLA showed significant PbLi ingress into the bulk FCI material that resulted in degradation of insulating properties of the FCI. Current material analyses at CIEMAT are based on advanced techniques, including characterization of FCI samples by FESEM to study PbLi ingress, imaging of cross sections, composition analysis by EDX and crack inspection. These analyses suggest that the ingress was caused by local defects in the protective inner CVD layer that might be originally present in the FCI or occurred during testing.

  3. Effects of water chemistry and fluid dynamics on wall thinning behavior. Part 1. Development of FAC model focused on water chemistry and composition of material

    International Nuclear Information System (INIS)

    Fujiwara, Kazutoshi; Domae, Masafumi; Ohta, Joji; Yoneda, Kimitoshi; Inada, Fumio

    2009-01-01

    Flow Accelerated Corrosion (FAC), which is one of the important subjects at fossil and nuclear power plans, is caused by the accelerated dissolution of protective oxide film due to the turbulent flow. The influence factors on FAC such as water chemistry, material, and fluid dynamics are closely related to the oxide property so that the risk of FAC can be reduced by the suitable control of water chemistry. There are some FAC models and evaluation codes of FAC rate. Some of them are used in wall thinning management of nuclear power plant in some country. Nevertheless, these FAC codes include many empirical parameters so that some uncertainty to evaluate the synergistic effectiveness of factors are the controversial point for the application of FAC code to wall thinning management in Japanese nuclear power plant. In this study, a FAC model that can evaluate the effect of temperature, NH3 concentration, chromium content, and dissolved oxygen concentration on FAC rate was developed by considering the diffusion of dissolved species. The critical dissolved oxygen concentration, which can inhibit FAC, was also calculated by this model. (author)

  4. Development of a molecular dynamic based cohesive zone model for prediction of an equivalent material behavior for Al/Al2O3 composite

    Energy Technology Data Exchange (ETDEWEB)

    Sazgar, A. [Center of Excellence in Design, Robotics and Automation, Department of Mechanical Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Movahhedy, M.R., E-mail: movahhed@sharif.edu [Center of Excellence in Design, Robotics and Automation, Department of Mechanical Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Mahnama, M. [School of Mechanical Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Sohrabpour, S. [Center of Excellence in Design, Robotics and Automation, Department of Mechanical Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of)

    2017-01-02

    The interfacial behavior of composites is often simulated using a cohesive zone model (CZM). In this approach, a traction-separation (T-S) relation between the matrix and reinforcement particles, which is often obtained from experimental results, is employed. However, since the determination of this relation from experimental results is difficult, the molecular dynamics (MD) simulation may be used as a virtual environment to obtain this relation. In this study, MD simulations under the normal and shear loadings are used to obtain the interface behavior of Al/Al2O3 composite material and to derive the T-S relation. For better agreement with Al/Al2O3 interfacial behavior, the exponential form of the T-S relation suggested by Needleman [1] is modified to account for thermal effects. The MD results are employed to develop a parameterized cohesive zone model which is implemented in a finite element model of the matrix-particle interactions. Stress-strain curves obtained from simulations under different loading conditions and volume fractions show a close correlation with experimental results. Finally, by studying the effects of strain rate and volume fraction of particles in Al(6061-T6)/Al2O3 composite, an equivalent homogeneous model is introduced which can predict the overall behavior of the composite.

  5. Using in situ nanocellulose-coating technology based on dynamic bacterial cultures for upgrading conventional biomedical materials and reinforcing nanocellulose hydrogels.

    Science.gov (United States)

    Zhang, Peng; Chen, Lin; Zhang, Qingsong; Jönsson, Leif J; Hong, Feng F

    2016-07-08

    Bacterial nanocellulose (BNC) is a microbial nanofibrillar hydrogel with many potential applications. Its use is largely restricted by insufficient strength when in a highly swollen state and by inefficient production using static cultivation. In this study, an in situ nanocellulose-coating technology created a fabric-frame reinforced nanocomposite of BNC hydrogel with superior strength but retained BNC native attributes. By using the proposed technology, production time could be reduced from 10 to 3 days to obtain a desirable hydrogel sheet with approximately the same thickness. This novel technology is easier to scale up and is more suitable for industrial-scale manufacture. The mechanical properties (tensile strength, suture retention strength) and gel characteristics (water holding, absorption and wicking ability) of the fabric-reinforced BNC hydrogel were investigated and compared with those of ordinary BNC hydrogel sheets. The results reveal that the fabric-reinforced BNC hydrogel was equivalent with regard to gel characteristics, and exhibited a qualitative improvement with regard to its mechanical properties. For more advanced applications, coating technology via dynamic bacterial cultures could be used to upgrade conventional biomedical fabrics, i.e. medical cotton gauze or other mesh materials, with nanocellulose. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1077-1084, 2016. © 2016 American Institute of Chemical Engineers.

  6. Between material and ideas

    DEFF Research Database (Denmark)

    Dahlstedt, Palle

    2012-01-01

    between a dynamic concept and the changing material form of the work. Combining ideas, tools, material and memory, creativity is described as a coherent, dynamic, and iterative process that navigates the space of the chosen medium, guided by the tools at hand, and by the continuously revised ideas...

  7. Material characterization models and test methods for historic building materials

    DEFF Research Database (Denmark)

    Hansen, Tessa Kvist; Peuhkuri, Ruut Hannele; Møller, Eva B.

    2017-01-01

    Predictions of long term hygrothermal performance can be assessed by dynamic hygrothermal simulations, in which material parameters are crucial input. Material parameters for especially historic materials are often unknown; therefore, there is a need to determine important parameters, and simple...

  8. Analysis of nano-sized irradiation-induced defects in Fe-base materials by means of small angle neutron scattering and molecular dynamics simulations

    International Nuclear Information System (INIS)

    Yu, G.

    2008-12-01

    of RAFM steels with Molecular Dynamics (MD) simulations of main expected nano-sized defects in irradiated pure Fe and Fe-He alloys, as model materials for RAFM steels, and simulations of their corresponding TEM images and SANS signals. In particular, the SANS signal of various types of defects was simulated for the first time. The methodology used in this work was the following: (i) SANS experiments were performed by applying a strong saturating magnetic field to unirradiated and irradiated specimens of three types of RAFM steels, namely the European EUROFER 97, the Japanese F82H and the Swiss OPTIMAX A steels. The available irradiated specimens included specimens which had been irradiated with 590 MeV protons in the Proton IRradiation EXperiment (PIREX) facility at the Paul Scherrer Institute (PSI) at temperatures in the range of 50-350 °C to doses in the range of 0.3-2.0 dpa. SANS spectra as well as values of the so-called A ratio, which represents the ratio of the total scattered intensity to the nuclear scattered intensity, were obtained for the various irradiation doses and temperatures investigated. (ii) MD simulations of atomic displacement cascades in pure Fe and in Fe-He alloys were performed using Embedded Atom Method (EAM) many-body interatomic potentials. The main nano-sized defects that should be produced in RAFM steels under irradiation were created by means of MD in pure Fe. These included dislocation loops of various types, voids, helium bubbles with various He concentration and Cr precipitates. (iii) TEM images of cascade damage and all the defects created by MD were simulated in the dark field/weak beam imaging modes by using the Electron Microscopy Software (EMS) developed by P.A. Stadelmann (EPFL) and analyzed in terms of variations of contrast intensities versus depth inside the specimen. (iv) The SANS signal provided by cascade damage and all the defects created by MD was simulated by using a slightly modified version of EMS, accounting for

  9. Limitations to the development of recombinant human embryonic kidney 293E cells using glutamine synthetase-mediated gene amplification: Methionine sulfoximine resistance.

    Science.gov (United States)

    Yu, Da Young; Noh, Soo Min; Lee, Gyun Min

    2016-08-10

    To investigate the feasibility of glutamine synthetase (GS)-mediated gene amplification in HEK293 cells for the high-level stable production of therapeutic proteins, HEK293E cells were transfected by the GS expression vector containing antibody genes and were selected at various methionine sulfoximine (MSX) concentrations in 96-well plates. For a comparison, CHOK1 cells were transfected by the same GS expression vector and selected at various MSX concentrations. Unlike CHOK1 cells, HEK293E cells producing high levels of antibodies were not selected at all. For HEK293E cells, the number of wells with the cell pool did not decrease with an increase in the concentration of MSX up to 500μM MSX. A q-RT-PCR analysis confirmed that the antibody genes in the HEK293E cells, unlike the CHOK1 cells, were not amplified after increasing the MSX concentration. It was found that the GS activity in HEK293E cells was much higher than that in CHOK1 cells (PMSX and therefore hampers GS-mediated gene amplification by MSX. Thus, in order to apply the GS-mediated gene amplification system to HEK293 cells, the endogenous GS expression level in HEK293 cells needs to be minimized by knock-out or down-regulation methods. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Investigation of dynamics of soft X-ray radiation of mixed-material wire-arrays on S-300 pulsed power generator

    NARCIS (Netherlands)

    Cai, HC; Chernenko, AC; Korolev, VD; Ustroev, GI; Ivanov, MI

    2004-01-01

    The dynamics of radiation spectra of fast Z-pinch plasmas was studied. The experiments were carried out on the S-300 pulsed power machine (4 MA, 0.15 Omega, 100 ns). By means of the polychromator, X-ray spectra of imploding wire arrays were measured in the range of 60 divided by 1500 eV, where the

  11. Poromechanical approach describing the moisture influence on the non-linear quasi-static and dynamic behaviour of porous building materials

    NARCIS (Netherlands)

    Carmeliet, J.; Abeele, van den K.E.A.

    2004-01-01

    The non-linear quasi-static and dynamic elastic behaviour of Berea sandstone has been experimentally analysed showing hysteresis and a strong influence of moisture especially in the lower saturation range. It is shown that non-linear hysteretic response originates within the "bond system" of the

  12. Effects of litter quality and parent material on organic matter characteristics and N-dynamics in Luxembourg beech and hornbeam forests

    NARCIS (Netherlands)

    Kooijman, A.M.; Martinez-Hernandez, G.B.

    2009-01-01

    To test effects of litter quality and soil conditions on N-dynamics, we selected seven forests in Luxembourg dominated by beech (Fagus sylvatica, L.) and hornbeam (Carpinus betulus L.), and located on acid loam, decalcified marl or limestone, and measured organic matter characteristics, microbial C

  13. Delta Dynamics

    DEFF Research Database (Denmark)

    Bendixen, Mette

    . The warming air temperature affects the soil temperature and permafrost thaws and destabilizes the material in the coastal zone. In Greenland, the warming temperature lowers the surface mass balance of the Greenland Ice Sheet and more material is transported to the coastal zone. The sea ice extent is thinning...... of a fjord and the second type is a wider fan-shaped open delta. Most deltas are directly coupled to the Greenland Ice Sheet or local icecaps and are highly influenced by the dynamics in the catchments. It is demonstrated how a modern changing climate directly affects delta dynamics, and that Greenlandic...... deltas are prograding, contrary to the global trend showing eroding Arctic coasts. Moreover, it is revealed that the increasing proglacial freshwater runoff, caused by a lowering of the surface mass balance of the Greenland Ice Sheet is the main determining agent in delta progradation. The final part...

  14. Combinatorial treatment with lithium chloride enhances recombinant antibody production in transiently transfected CHO and HEK293E cells

    DEFF Research Database (Denmark)

    Kim, Che Lin; Kwang Ha, Tae; Min Lee, Gyun

    2016-01-01

    Lithium chloride (LiCl), which induces cell cycle arrest at G2/M phase, is known as a specific production rate (qp)-enhancing additive in recombinant Chinese hamster ovary (CHO) cell culture. To determine the potential of LiCl as a chemical additive that enhances transient gene expression (TGE), Li......Cl was added to the CHO-NK and human embryonic kidney 293E (HEK293E) cell cultures before and/or after transfection with polyethylenimine as a transfection reagent. The effect of this addition on transfection efficiency (pre-treatment) and qp enhancement during TGE (post-treatment) was examined. For the TGE...... of monoclonal antibody (mAb) in CHO-NK cells, pretreatment alone with 10 mM LiCl and post-treatment alone with 5 mM LiCl resulted in 1.2- and 3.4-fold increase of maximum mAb concentration (MMC), respectively, compared with the TGE without LiCl treatment. Furthermore, combinatorial treatment with LiCl (10 m...

  15. A novel approach in Eliashberg theory of superconductivity with ab-initio static and dynamic Coulomb interaction applicable for real materials

    Energy Technology Data Exchange (ETDEWEB)

    Davydov, Arkadiy; Sanna, Antonio; Sharma, Sangeeta; Dewhurst, John Kay; Gross, E.K.U. [Max Planck Institute of Microstructure Physics, Halle (Saale) (Germany)

    2016-07-01

    In standard Eliashberg methods the Coulomb interaction is usually restricted to the use of a single phenomenological parameter μ{sup *} adjusted to give the right superconducting critical temperature (T{sub c}). In this work we present a parameter-free Eliashberg approach, in which we treat the screened Coulomb interaction within the random phase approximation (RPA) in its static and full dynamic limit. The full energy range of the Coulomb interaction is taken into account, which becomes computationally affordable with the introduction of a suitable isotropic approximation. We have tested the method on a set of conventional superconductors. We will discuss the reliability of the predicted T{sub c} both by using a static and a dynamic Coulomb interaction.

  16. Gliadin Fragments and a Specific Gliadin 33-mer Peptide Close KATP Channels and Induce Insulin Secretion in INS-1E Cells and Rat Islets of Langerhans

    DEFF Research Database (Denmark)

    Dall, Morten; Calloe, Kirstine; Haupt-Jorgensen, Martin

    2013-01-01

    . A similar effect was observed in isolated rat islets (1.6-fold increase). In INS-1E cells, diazoxide reduced the stimulatory effect of gliadin digest. Additionally, gliadin digest was shown to decrease current through KATP-channels. A specific gliadin 33-mer had a similar effect, both on current and insulin...

  17. Inhibition of nuclear factor-kappaB or Bax prevents endoplasmic reticulum stress- but not nitric oxide-mediated apoptosis in INS-1E cells

    DEFF Research Database (Denmark)

    Tonnesen, Morten F; Grunnet, Lars G; Friberg, Josefine

    2009-01-01

    . Exposure of INS-1E cells to TG or SNAP caused caspase-3 cleavage and apoptosis. Both TG and SNAP induced activation of the proapoptotic transcription factor CCAAT/enhancer-binding protein homologous protein (CHOP). However, other classical ER stress-induced markers such as up-regulation of ER chaperone Bip...

  18. Real-Space Imaging of Carrier Dynamics of Materials Surfaces by Second-Generation Four-Dimensional Scanning Ultrafast Electron Microscopy

    KAUST Repository

    Sun, Jingya; Melnikov, Vasily; Khan, Jafar Iqbal; Mohammed, Omar F.

    2015-01-01

    , we establish a second generation of four-dimensional scanning ultrafast electron microscopy (4D S-UEM) and demonstrate the ability to record time-resolved images (snapshots) of material surfaces with 650 fs and ∼5 nm temporal and spatial resolutions

  19. Dictionary materials engineering, materials testing

    International Nuclear Information System (INIS)

    1994-01-01

    This dictionary contains about 9,500 entries in each part of the following fields: 1) Materials using and selection; 2) Mechanical engineering materials -Metallic materials - Non-metallic inorganic materials - Plastics - Composites -Materials damage and protection; 3) Electrical and electronics materials -Conductor materials - Semiconductors - magnetic materials - Dielectric materials - non-conducting materials; 4) Materials testing - Mechanical methods - Analytical methods - Structure investigation - Complex methods - Measurement of physical properties - Non-destructive testing. (orig.) [de

  20. Study into the mechanisms of hydrogen contamination of niobium as a material for superconducting radiofrequency cavities. Molecular dynamics studies for simulation of the hydrogen diffusion processes

    International Nuclear Information System (INIS)

    Roux, B.

    1993-01-01

    Superconducting radiofrequency cavities were chosen for most of the future particle accelerators. In the case of pure niobium cavities, several laboratories have observed degradation of superconducting properties related to the conditions of the cooling down process. This effect seems to stem from hydrogen contamination which occurs during surface treatments. With the aim to study the influence of different surface treatments on the hydrogen contamination depth concentration profiling of the near surface region (the first 200 nm) was first carried out by the classical ERDA technique with 30 nm depth resolution. In order to better localize hydrogen, the initial particle selecting device (Teflon foil) was replaced by an electromagnetic (ExB) filter improving then the depth resolution by a factor three. This study reveals an hydrogen segregation at the niobium surface. Such a result is in contradiction with the relative high experimental value of the hydrogen diffusion coefficient given by the literature. To understand the trapping mechanism of hydrogen, a simulation by molecular dynamics of this impurity diffusion process was performed. This approach requires the knowledge of the interatomic potential. The potential parameters were fitted with static and dynamic tests. Nb-Nb interaction is based on many body potential. Nb-H is represented by two body potential. The Arrhenius diagram of the diffusion coefficient achieved by dynamic for a single crystal provides too small activation energy in comparison with experimental results. However, in presence of defects, a simulation proves a large increase of these values. It is only around 1000 K that the diffusion of hydrogen is not altered by defects. This conclusion confirms the experimental results concerning a good characteristic of superconducting cavities after thermal treatments. (orig.)

  1. Influence of internal thermal mass on the indoor thermal dynamics and integration of phase change materials in furniture for building energy storage

    DEFF Research Database (Denmark)

    Johra, Hicham; Heiselberg, Per Kvols

    2017-01-01

    The increasing share of intermittent renewable energy on the grid encourages researchers to develop demand-side management strategies. Passive heat storage in the indoor space is a promising solution to improve the building energy flexibility. It relies on an accurate control of the transient...... building temperature. However, many of the current numerical models for building energy systems assume empty rooms and do not account entirely for the internal thermal inertia of objects like furniture. This review article points out that such assumption is not valid for dynamic calculations...

  2. Comparison of a static and a dynamic in vitro model to estimate the bioaccessibility of As, Cd, Pb and Hg from food reference materials Fucus sp. (IAEA-140/TM) and Lobster hepatopancreas (TORT-2)

    Energy Technology Data Exchange (ETDEWEB)

    Torres-Escribano, Silvia [Instituto de Agroquimica y Tecnologia de Alimentos (IATA-CSIC), Apdo. 73, 46100, Burjassot, Valencia (Spain); Denis, Sylvain; Blanquet-Diot, Stephanie [Clermont Universite, Universite d' Auvergne, Centre de Recherche en Nutrition Humaine Auvergne, ERT 18, Conception ingenierie et developpement de l' aliment et du medicament, BP 10448, F-63000 Clermont-Ferrand (France); Calatayud, Marta [Instituto de Agroquimica y Tecnologia de Alimentos (IATA-CSIC), Apdo. 73, 46100, Burjassot, Valencia (Spain); Barrios, Laura [Departamento de Informatica Cientifica (SGAI-CSIC), C/ Pinar 19, 28006 Madrid (Spain); Velez, Dinoraz, E-mail: deni@iata.csic.es [Instituto de Agroquimica y Tecnologia de Alimentos (IATA-CSIC), Apdo. 73, 46100, Burjassot, Valencia (Spain); Alric, Monique [Clermont Universite, Universite d' Auvergne, Centre de Recherche en Nutrition Humaine Auvergne, ERT 18, Conception ingenierie et developpement de l' aliment et du medicament, BP 10448, F-63000 Clermont-Ferrand (France); Montoro, Rosa [Instituto de Agroquimica y Tecnologia de Alimentos (IATA-CSIC), Apdo. 73, 46100, Burjassot, Valencia (Spain)

    2011-01-01

    Bioaccessibility, the fraction of an element solubilized during gastrointestinal digestion and available for absorption, is a factor that should be considered when evaluating the health risk of contaminants from food. Static and dynamic models that mimic human physiological conditions have been used to evaluate bioaccessibility. This preliminary study compares the bioaccessibility of arsenic (As), cadmium (Cd), lead (Pb) and mercury (Hg) in two food certified reference materials (CRMs) (seaweed: Fucus sp., IAEA-140/TM; Lobster hepatopancreas: TORT-2), using two in vitro gastrointestinal digestion methods: a static method (SM) and a dynamic multicompartment method (TIM-1). There are significant differences (p < 0.05) between the bioaccessible values of As, Cd, Pb and Hg obtained by SM and TIM-1 in the two CRMs. The specific form in which the elements studied are present in the CRM may help to explain the bioaccessibility values obtained. - Research Highlights: {yields}Data are reported for As, Cd, Pb and Hg bioaccessibility from food CRMs. {yields}The static and TIM-1 methods give significantly different bioaccessibility values. {yields}The possible influence of speciation on bioaccessibility is discussed. {yields}To improve bioaccessibility quality data, food reference materials are needed.

  3. Comparison of a static and a dynamic in vitro model to estimate the bioaccessibility of As, Cd, Pb and Hg from food reference materials Fucus sp. (IAEA-140/TM) and Lobster hepatopancreas (TORT-2)

    International Nuclear Information System (INIS)

    Torres-Escribano, Silvia; Denis, Sylvain; Blanquet-Diot, Stephanie; Calatayud, Marta; Barrios, Laura; Velez, Dinoraz; Alric, Monique; Montoro, Rosa

    2011-01-01

    Bioaccessibility, the fraction of an element solubilized during gastrointestinal digestion and available for absorption, is a factor that should be considered when evaluating the health risk of contaminants from food. Static and dynamic models that mimic human physiological conditions have been used to evaluate bioaccessibility. This preliminary study compares the bioaccessibility of arsenic (As), cadmium (Cd), lead (Pb) and mercury (Hg) in two food certified reference materials (CRMs) (seaweed: Fucus sp., IAEA-140/TM; Lobster hepatopancreas: TORT-2), using two in vitro gastrointestinal digestion methods: a static method (SM) and a dynamic multicompartment method (TIM-1). There are significant differences (p < 0.05) between the bioaccessible values of As, Cd, Pb and Hg obtained by SM and TIM-1 in the two CRMs. The specific form in which the elements studied are present in the CRM may help to explain the bioaccessibility values obtained. - Research Highlights: →Data are reported for As, Cd, Pb and Hg bioaccessibility from food CRMs. →The static and TIM-1 methods give significantly different bioaccessibility values. →The possible influence of speciation on bioaccessibility is discussed. →To improve bioaccessibility quality data, food reference materials are needed.

  4. AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 34th and AIAA/ASME Adaptive Structures Forum, La Jolla, CA, Apr. 19-22, 1993, Technical Papers. Pts. 1-6

    Science.gov (United States)

    Topics addressed include the prediction of helicopter component loads using neural networks, spacecraft on-orbit coupled loads analysis, hypersonic flutter of a curved shallow panel with aerodynamic heating, thermal-acoustic fatigue of ceramic matrix composite materials, transition elements based on transfinite interpolation, damage progression in stiffened composite panels, a direct treatment of min-max dynamic response optimization problems, and sources of helicopter rotor hub inplane shears. Also discussed are dynamics of a layered elastic system, confidence bounds on structural reliability, mixed triangular space-time finite elements, advanced transparency development for USAF aircraft, a low-velocity impact on a graphite/PEEK, an automated mode-tracking strategy, transonic flutter suppression by a passive flap, a nonlinear response of composite panels to random excitation, an optimal placement of elastic supports on a simply supported plate, a probabilistic assessment of composite structures, a model for mode I failure of laminated composites, a residual flexibility approach to multibody dynamics,and multilayer piezoelectric actuators.

  5. Statistical analysis of the structure and dynamics of material and human resources in public education over the past two academic years in Bacau

    Directory of Open Access Journals (Sweden)

    Eugenia Harja

    2010-12-01

    Full Text Available The public university education in Bacau, represented by “Vasile Alecsandri” University from Bacau has developed over the past two years not only in terms of student numbers, but as human and material resources available to them. After the number of students per teacher, public higher education from Bacau is situated on the second place after Iasi, the number of teachers representing 1% of the country. The structure by scientific degrees of teachers has improved in the last year, reaching over 36% professors and lecturers and 144 PhDs. Over 55% of the teachers are younger than 40 years. The material basis has improved both quantitatively and qualitatively by putting into use a new building, bringing an additional 27 classrooms and 11 seminar rooms and providing the conditions of modern higher education.

  6. Development of computational dynamic properties analysis method and optimum design method of tissue construction under consideration of microstructure of materials for nuclear power

    International Nuclear Information System (INIS)

    Shiraishi, Haruki; Tabuchi, Masaaki; Nakasone, Yuji

    1999-01-01

    A practical reactor core material produces particles by irradiation in the matrix. The second phase particle lattice was defined and the effects of its basic parameters on the stress-strain curve were evaluated. As the basic parameters, 0.01 to 0.95 μm of particle diameter, 1.0μm of grain spacing and 0.3 of work-hardening exponent were used. The effect of the particle diameter on the stress-strain curve was studied by the large deformation finite element method. The concentration area of distortion was produced from the back of the second phase particles, and its process specified the sharp of stress-strain curve. The calculation method did not assume breaking of particles and separation of the interface of particle and matrix. So that, the values obtained showed the upper limits of strength, ductility and fracture toughness of the composite materials. (S.Y.)

  7. Determination of Physical Properties of Carbon Materials by Results of Ablative Experiments Con-ducted in the Jets of Gas Dynamic Units

    Directory of Open Access Journals (Sweden)

    V. V. Gorsky

    2015-01-01

    Full Text Available The process of hypersonic vehicles’ movement in the dense layers of the atmosphere is accompanied by the considerable combustion of heat shield, which effects on the aerodynamic, mass-inertial and centering characteristics of the product.For correct calculation of model's movement parameters it is necessary:* Using the theoretical and computation methods for determining ablative characteristics of heat-protective materials;* Taking into account all the basic physical and chemical processes, involved in their ablation, using the above mentioned methods;* Testing these techniques in the wide range of experimental data. This physic-mathematical model of carbon materials (CM aerothermochemical destruction is based on using the following:* Arrhenius equations to calculate carbon kinetic oxidation;* Langmuir-Knudsen formula to calculate the velocity of non-equilibrium carbon’s sublimation;* Carbon erosion law represented as a unique dependence of this process velocity on the gas pressure on the wall.Mathematical description of all major processes included in this formulation of the problem, contains a number of "free" parameters that can be determined only on the basis of comparison of theoretical and experimental data according to total ablation characteristics of these materials.This comparison was performed in the article applicable to the tests conditions of modern CM in the stream of electric arc plant and in combustion products of liquid-propellant rocket engines.As the result, the data of kinetic of carbon oxidation by atomic oxygen at sublimation mode of material ablation were obtained for the first time. Carbon erosion law under high pressure was established for the first time.The new approach to processing of ablation experiments is enunciated. Using this approach allows to turn this experiments for CM from comparative tests into the tests to determine ablation properties of thermal protection. Moreover, it enables us also to use the

  8. Applications of Neutron Scattering in the Chemical Industry: Proton Dynamics of Highly Dispersed Materials, Characterization of Fuel Cell Catalysts, and Catalysts from Large-Scale Chemical Processes

    Science.gov (United States)

    Albers, Peter W.; Parker, Stewart F.

    The attractiveness of neutron scattering techniques for the detailed characterization of materials of high degrees of dispersity and structural complexity as encountered in the chemical industry is discussed. Neutron scattering picks up where other analytical methods leave off because of the physico-chemical properties of finely divided products and materials whose absorption behavior toward electromagnetic radiation and electrical conductivity causes serious problems. This is demonstrated by presenting typical applications from large-scale production technology and industrial catalysis. These include the determination of the proton-related surface chemistry of advanced materials that are used as reinforcing fillers in the manufacture of tires, where interrelations between surface chemistry, rheological properties, improved safety, and significant reduction of fuel consumption are the focus of recent developments. Neutron scattering allows surface science studies of the dissociative adsorption of hydrogen on nanodispersed, supported precious metal particles of fuel cell catalysts under in situ loading at realistic gas pressures of about 1 bar. Insight into the occupation of catalytically relevant surface sites provides valuable information about the catalyst in the working state and supplies essential scientific input for tailoring better catalysts by technologists. The impact of deactivation phenomena on industrial catalysts by coke deposition, chemical transformation of carbonaceous deposits, and other processes in catalytic hydrogenation processes that result in significant shortening of the time of useful operation in large-scale plants can often be traced back in detail to surface or bulk properties of catalysts or materials of catalytic relevance. A better understanding of avoidable or unavoidable aspects of catalyst deactivation phenomena under certain in-process conditions and the development of effective means for reducing deactivation leads to more energy

  9. Materials @ LANL: Solutions for National Security Challenges

    Science.gov (United States)

    Teter, David

    2012-10-01

    Materials science activities impact many programmatic missions at LANL including nuclear weapons, nuclear energy, renewable energy, global security and nonproliferation. An overview of the LANL materials science strategy and examples of materials science programs will be presented. Major materials leadership areas are in materials dynamics, actinides and correlated electron materials, materials in radiation extremes, energetic materials, integrated nanomaterials and complex functional materials. Los Alamos is also planning a large-scale, signature science facility called MaRIE (Matter Radiation Interactions in Extremes) to address in-situ characterization of materials in dynamic and radiation environments using multiple high energy probes. An overview of this facility will also be presented.

  10. Material Science

    Energy Technology Data Exchange (ETDEWEB)

    Won, Dong Yeon; Kim, Heung

    1987-08-15

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

  11. Material Science

    International Nuclear Information System (INIS)

    Won, Dong Yeon; Kim, Heung

    1987-08-01

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

  12. Materials and material testing

    International Nuclear Information System (INIS)

    Joergens, H.

    1978-01-01

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

  13. Dynamics in Complex Coacervates

    Science.gov (United States)

    Perry, Sarah

    Understanding the dynamics of a material provides detailed information about the self-assembly, structure, and intermolecular interactions present in a material. While rheological methods have long been used for the characterization of complex coacervate-based materials, it remains a challenge to predict the dynamics for a new system of materials. Furthermore, most work reports only qualitative trends exist as to how parameters such as charge stoichiometry, ionic strength, and polymer chain length impact self-assembly and material dynamics, and there is little information on the effects of polymer architecture or the organization of charges within a polymer. We seek to link thermodynamic studies of coacervation phase behavior with material dynamics through a carefully-controlled, systematic study of coacervate linear viscoelasticity for different polymer chemistries. We couple various methods of characterizing the dynamics of polymer-based complex coacervates, including the time-salt superposition methods developed first by Spruijt and coworkers to establish a more mechanistic strategy for comparing the material dynamics and linear viscoelasticity of different systems. Acknowledgment is made to the Donors of the American Chemical Society Petroleum Research Fund for support of this research.

  14. Invited article: The fast readout low noise camera as a versatile x-ray detector for time resolved dispersive extended x-ray absorption fine structure and diffraction studies of dynamic problems in materials science, chemistry, and catalysis

    International Nuclear Information System (INIS)

    Labiche, Jean-Claude; Mathon, Olivier; Pascarelli, Sakura; Newton, Mark A.; Ferre, Gemma Guilera; Curfs, Caroline; Vaughan, Gavin; Homs, Alejandro; Carreiras, David Fernandez

    2007-01-01

    Originally conceived and developed at the European Synchrotron Radiation Facility (ESRF) as an 'area' detector for rapid x-ray imaging studies, the fast readout low noise (FReLoN) detector of the ESRF [J.-C. Labiche, ESRF Newsletter 25, 41 (1996)] has been demonstrated to be a highly versatile and unique detector. Charge coupled device (CCD) cameras at present available on the public market offer either a high dynamic range or a high readout speed. A compromise between signal dynamic range and readout speed is always sought. The parameters of the commercial cameras can sometimes be tuned, in order to better fulfill the needs of specific experiments, but in general these cameras have a poor duty cycle (i.e., the signal integration time is much smaller than the readout time). In order to address scientific problems such as time resolved experiments at the ESRF, a FReLoN camera has been developed by the Instrument Support Group at ESRF. This camera is a low noise CCD camera that combines high dynamic range, high readout speed, accuracy, and improved duty cycle in a single image. In this paper, we show its application in a quasi-one-dimensional sense to dynamic problems in materials science, catalysis, and chemistry that require data acquisition on a time scale of milliseconds or a few tens of milliseconds. It is demonstrated that in this mode the FReLoN can be applied equally to the investigation of rapid changes in long range order (via diffraction) and local order (via energy dispersive extended x-ray absorption fine structure) and in situations of x-ray hardness and flux beyond the capacity of other detectors

  15. Corrigendum to "Dynamics of a flexible tethered satellite system utilising various materials for coplanar and non-coplanar models" [Adv. Space Res. 56 (2015) 648-663

    Science.gov (United States)

    Hong, Aaron Aw Teik; Varatharajoo, Renuganth

    2015-12-01

    The authors would like to thank Dr. N.A. Ismail for some of the discussions found in her thesis as these discussions have facilitated to achieve some of the results published in this article. Therefore, Ismail, N.A., "The Dynamics of a Flexible Motorised Momentum Exchange Tether (MMET)", PhD. thesis, University of Glasgow, UK, pp. 26-41, 2012 is cited accordingly herein. The thesis was missed out from the reference list in the original version of this article due to an oversight with no other intention. Similarly the thesis by Stevens, R.E., "Optimal Control of Electrodynamic Tether Satellites", PhD. thesis, Air Force Institute of Technology, USA, pp. 87-96, 2008 is referred for a further readership completeness.

  16. Extended application of Kohn-Sham first-principles molecular dynamics method with plane wave approximation at high energy—From cold materials to hot dense plasmas

    International Nuclear Information System (INIS)

    Zhang, Shen; Kang, Wei; Wang, Hongwei; Zhang, Ping; He, X. T.

    2016-01-01

    An extended first-principles molecular dynamics (FPMD) method based on Kohn-Sham scheme is proposed to elevate the temperature limit of the FPMD method in the calculation of dense plasmas. The extended method treats the wave functions of high energy electrons as plane waves analytically and thus expands the application of the FPMD method to the region of hot dense plasmas without suffering from the formidable computational costs. In addition, the extended method inherits the high accuracy of the Kohn-Sham scheme and keeps the information of electronic structures. This gives an edge to the extended method in the calculation of mixtures of plasmas composed of heterogeneous ions, high-Z dense plasmas, lowering of ionization potentials, X-ray absorption/emission spectra, and opacities, which are of particular interest to astrophysics, inertial confinement fusion engineering, and laboratory astrophysics.

  17. Extended application of Kohn-Sham first-principles molecular dynamics method with plane wave approximation at high energy—From cold materials to hot dense plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shen; Kang, Wei, E-mail: weikang@pku.edu.cn [Center for Applied Physics and Technology, HEDPS, Peking University, Beijing 100871 (China); College of Engineering, Peking University, Beijing 100871 (China); Wang, Hongwei [College of Engineering, Peking University, Beijing 100871 (China); Zhang, Ping, E-mail: zhang-ping@iapcm.ac.cn [Center for Applied Physics and Technology, HEDPS, Peking University, Beijing 100871 (China); LCP, Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China); He, X. T., E-mail: xthe@iapcm.ac.cn [Center for Applied Physics and Technology, HEDPS, and IFSA Collaborative Innovation Center of MoE, Peking University, Beijing 100871 (China); Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China)

    2016-04-15

    An extended first-principles molecular dynamics (FPMD) method based on Kohn-Sham scheme is proposed to elevate the temperature limit of the FPMD method in the calculation of dense plasmas. The extended method treats the wave functions of high energy electrons as plane waves analytically and thus expands the application of the FPMD method to the region of hot dense plasmas without suffering from the formidable computational costs. In addition, the extended method inherits the high accuracy of the Kohn-Sham scheme and keeps the information of electronic structures. This gives an edge to the extended method in the calculation of mixtures of plasmas composed of heterogeneous ions, high-Z dense plasmas, lowering of ionization potentials, X-ray absorption/emission spectra, and opacities, which are of particular interest to astrophysics, inertial confinement fusion engineering, and laboratory astrophysics.

  18. Using Remote Sensing and Field Observations of Colored Dissolved Organic Material (CDOM) to Improve Understanding of Carbon Dynamics at the Land-Ocean Interface

    Science.gov (United States)

    Lai, L.; Tzortziou, M.; Gilerson, A.; Foster, R.

    2013-12-01

    Dissolved Organic Matter (DOM) and its colored component, (CDOM) are sensitive indicators of environmental pollution, nutrient enrichment, water quality and plays a key role in a broad range of processes and climate-related biogeochemical cycles in estuarine and coastal ecosystems. Because of its strong influence on how ocean color is viewed, CDOM can provide an invaluable optical tool for coastal zone environmental assessment and from space. There is a continuous cycle of sources and sinks of CDOM from terrestrial sources to the wetlands to the estuaries and to the ocean waters. Terrestrial inputs from natural processes, anthropogenic activities, exchanges with the atmosphere, rich biodiversity and high primary productivity, physical, photochemical and microbial processes affect not only the amount but also the quality and optical signature of CDOM in near-shore waters. In this study, new measurements are presented of the optical characteristics of CDOM collected from the Chesapeake Bay estuarine environment. Measured parameters include absorption spectra, estimated spectral slopes, slope ratios, DOC-specific CDOM absorption as well as 3D CDOM fluorescence emission-excitation matrices. Such results will provide insight of the measured CDOM in this complex environment and the complex process that affect CDOM quality and amount during transport to the estuary and coastal ocean. New field campaigns will be conducted in August and September in the Chesapeake Bay estuary and the coast of the Gulf of Mexico to collect more samples for analysis of CDOM dynamics and link field observations and measurements to satellite ocean color retrievals of estuarine biogeochemical processes. In addition, advanced satellite CDOM data distribution and usage is discussed as it has considerable operational value and practical application beyond the scientific community and research. Keywords: CDOM, carbon dynamics, estuaries, coastal ecosystems, optical properties, satellite applications

  19. Rare earth permanent-magnet alloys’ high temperature phase transformation in situ and dynamic observation and its application in material design

    CERN Document Server

    Pan, Shuming

    2013-01-01

    The process of high temperature phase transition of rare earth permanent-magnet alloys is revealed by photographs taken by high voltage TEM. The relationship between the formation of nanocrystal and magnetic properties is discussed in detail, which effects alloys composition and preparation process. The experiment results verified some presumptions, and were valuable for subsequent scientific research and creating new permanent-magnet alloys. The publication is intended for researchers, engineers and managers in the field of material science, metallurgy, and physics. Prof. Shuming Pan is senior engineer of Beijing General Research Institute of Non-ferrous Metal.

  20. Nonlinear dynamics of structures

    CERN Document Server

    Oller, Sergio

    2014-01-01

    This book lays the foundation of knowledge that will allow a better understanding of nonlinear phenomena that occur in structural dynamics.   This work is intended for graduate engineering students who want to expand their knowledge on the dynamic behavior of structures, specifically in the nonlinear field, by presenting the basis of dynamic balance in non‐linear behavior structures due to the material and kinematics mechanical effects.   Particularly, this publication shows the solution of the equation of dynamic equilibrium for structure with nonlinear time‐independent materials (plasticity, damage and frequencies evolution), as well as those time dependent non‐linear behavior materials (viscoelasticity and viscoplasticity). The convergence conditions for the non‐linear dynamic structure solution  are studied, and the theoretical concepts and its programming algorithms are presented.  

  1. Invitation to dynamical systems

    CERN Document Server

    Scheinerman, Edward R

    2012-01-01

    This text is designed for those who wish to study mathematics beyond linear algebra but are unready for abstract material. Rather than a theorem-proof-corollary exposition, it stresses geometry, intuition, and dynamical systems. 1996 edition.

  2. Observing the amorphous-to-crystalline phase transition in Ge{sub 2}Sb{sub 2}Te{sub 5} non-volatile memory materials from ab initio molecular-dynamics simulations

    Energy Technology Data Exchange (ETDEWEB)

    Lee, T.H.; Elliott, S.R. [Department of Chemistry, University of Cambridge, Lensfield Road, CB2 1EW Cambridge (United Kingdom)

    2012-10-15

    Phase-change memory is a promising candidate for the next generation of non-volatile memory devices. This technology utilizes reversible phase transitions between amorphous and crystalline phases of a recording material, and has been successfully used in rewritable optical data storage, revealing its feasibility. In spite of the importance of understanding the nucleation and growth processes that play a critical role in the phase transition, this understanding is still incomplete. Here, we present observations of the early stages of crystallization in Ge{sub 2}Sb{sub 2}Te{sub 5} materials through ab initio molecular-dynamics simulations. Planar structures, including fourfold rings and planes, play an important role in the formation and growth of crystalline clusters in the amorphous matrix. At the same time, vacancies facilitate crystallization by providing space at the glass-crystalline interface for atomic diffusion, which results in fast crystal growth, as observed in simulations and experiments. The microscopic mechanism of crystallization presented here may deepen our understanding of the phase transition occurring in real devices, providing an opportunity to optimize the memory performance of phase-change materials. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Accurate treatment of material interface dynamics in the calculation of one-dimensional two-phase flows by the integral method of characteristics

    International Nuclear Information System (INIS)

    Shin, Y.W.; Wiedermann, A.H.

    1984-01-01

    Accurate numerical methods for treating the junction and boundary conditions needed in the transient two-phase flows of a piping network were published earlier by us; the same methods are used to formulate the treatment of the material interface as a moving boundary. The method formulated is used in a computer program to calculate sample problems designed to test the numerical methods as to their ability and the accuracy limits for calculation of the transient two-phase flows in the piping network downstream of a PWR pressurizer. Independent exact analytical solutions for the sample problems are used as the basis of a critical evaluation of the proposed numerical methods. The evaluation revealed that the proposed boundary scheme indeed generates very accurate numerical results. However, in some extreme flow conditions, numerical difficulties were experienced that eventually led to numerical instability. This paper discusses further a special technique to overcome the difficulty

  4. Effect of the raw materials and mixing ratio of composted wastes on the dynamic of organic matter stabilization and nitrogen availability in composts of Sub-Saharan Africa.

    Science.gov (United States)

    Kaboré, Théodore Wind-Tinbnoma; Houot, Sabine; Hien, Edmond; Zombré, Prosper; Hien, Victor; Masse, Dominique

    2010-02-01

    The effect of raw materials and their proportions in initial mixtures on organic matter (OM) stabilization and nitrogen (N) availability during pit composting in Sub-Saharan Africa was assessed using biochemical fractionation and laboratory incubations to characterize composts sampled throughout the composting process. Stabilization of OM occurred more rapidly in mixtures with slaughter-house wastes, it was progressive in mixture with household refuses while tree leaves compost remained unstable. Carbon mineralization from compost samples was positively correlated to water soluble and hemicellulose-like organic fractions. Mixtures containing large proportions of household refuses reached the highest stability and total N but available N remained weak. Slaughter-house wastes in the initial mixtures made possible to reach good OM stabilization and the largest N availability. The nature of initial mixing influenced composting parameters, OM stabilization and N availability. It is suggested mixing household refuses and slaughter-house wastes with tree leaves to reach better amending and fertilizer qualities of composts.

  5. The morphofunctional state of Purkin'e cells in the cerebellum of new-born rats following laser and gamma-ray exposure

    International Nuclear Information System (INIS)

    Zubkova, S.M.; Popov, V.I.

    1993-01-01

    Following of local laser (632.8 nm, 6.3. J/cm 2 ) and whole-body Gy gamma-ray exposures of new-born rats the contrast changes of morphometrical indices, RNA amount, and chromatophilia of Purkin'e cells in the cerebellum were seen. The preliminary laser exposure of new-born rat cerebellum artially increased activity of karyogene structures of the cerebellum cells which were inhibited by 6.37 Gy gamma-rays

  6. Development of e-module combining science process skills and dynamics motion material to increasing critical thinking skills and improve student learning motivation senior high school

    Directory of Open Access Journals (Sweden)

    Fengky Adie Perdana

    2017-02-01

    Full Text Available Learning media is one of the most components in the teaching and learning process. This research was conducted to design and develop the electronic modules combining science process skills and dynamics motion content for increasing critical thinking skills and improve student learning motivation for senior high school. The Methods used in this research is Research and Development (R&D. Model research and development using a research 4D Thiagarajan model. Physics module was developed using science process skills approach: observing, formulating the problem, formulating a hypothesis, identify variables, conduct experiments, analyse the data, summarise and communicate. The results showed that: 1 the electronics module has been developed by integrating the science process skills for enhancing critical thinking skills and student motivation. 2 Electronic Module Physics-based science process skills meet the criteria very well, judging from the results of validation content, validation media, validation of peer education and practitioners, with an average value of 3.80 is greater than the minimum eligibility 3.78. 3 effectiveness the modules of science process skills got N-gain value obtained from a large trial in grade samples of 0.67 and 0.59 in the control group were categorised as moderate. 4 Implementation of electronic modules Physics-based science process skills is considered an effective to enhance the students' motivation. Statistical analysis showed a significance value of 0.027 is lower than the significance level α = 0.05, this means that there are significant differences between learning motivation grade sample and the control class. As a result of analysis data obtained from the research, it was seen that the students' motivation that uses Physics module based science process skills better than conventional learning.

  7. High dynamic range emission measurements of shocked energetic materials: Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)

    Science.gov (United States)

    Bassett, Will P.; Dlott, Dana D.

    2016-06-01

    A new emission apparatus with high time resolution and high dynamic range was used to study shock-induced ignition of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine in the form of ultrafine powder (4 ± 3 μm particle size), over a range of impact velocities (0.8-4.3 km s-1) and impact durations (2.5-16 ns). A graybody model was used to extract graybody emissivities and time-dependent temperatures from a few ns to 100 μs. The emission transients consisted of three parts: a 6700 K nanosecond burst during the shocks, a 4000-4500 K temperature spike near 0.3 μs followed by a ˜3300 K tail extending out to ˜100 μs. These temperatures varied remarkably little with impact velocity and duration, while the emission intensities and emissivities changed by over an order of magnitude. The emissivity changes were interpreted with a hot spot model, where hot spot temperatures reached a maximum of 6700 K and the hot spot volume fractions increased from 5% to 100% as impact velocity increased from 1 to 3 km s-1. Changing shock durations in the 2.5-16 ns range had noticeable effects on the microsecond emission. The 0.3 μs temperature spike was much smaller or absent with 2.5 ns shocks, but prominent with longer durations. An explanation for these effects was put forth that invoked the formation of carbon-rich clusters during the shock. In this view, cluster formation was minimal with 2.5 ns shocks, but longer-duration shocks produced increasingly larger clusters, and the 0.3 μs temperature spikes represented cluster ignition.

  8. New Materials = New Expressive Powers: Smart Material Interfaces and Arts, experience via smart materials

    NARCIS (Netherlands)

    Minuto, A.; Pittarello, Fabio; Nijholt, Antinus

    2014-01-01

    It is not easy for a growing artist to find his poetry. Smart materials could be an answer for those who are looking for new forms of art. Smart Material Interfaces (SMI) define a new interaction paradigm based on dynamic modications of the innovative materials' properties. SMI can be applied in

  9. Characterization of dynamic thermal control schemes and heat transfer pathways for incorporating variable emissivity electrochromic materials into a space suit heat rejection system

    Science.gov (United States)

    Massina, Christopher James

    The feasibility of conducting long duration human spaceflight missions is largely dependent on the provision of consumables such as oxygen, water, and food. In addition to meeting crew metabolic needs, water sublimation has long served as the primary heat rejection mechanism in space suits during extravehicular activity (EVA). During a single eight hour EVA, approximately 3.6 kg (8 lbm) of water is lost from the current suit. Reducing the amount of expended water during EVA is a long standing goal of space suit life support systems designers; but to date, no alternate thermal control mechanism has demonstrated the ability to completely eliminate the loss. One proposed concept is to convert the majority of a space suit's surface area into a radiator such that the local environment can be used as a radiative thermal sink for rejecting heat without mass loss. Due to natural variations in both internal (metabolic) loads and external (environmental) sink temperatures, radiative transport must be actively modulated in order to maintain an acceptable thermal balance. Here, variable emissivity electrochromic devices are examined as the primary mechanism for enabling variable heat rejection. This dissertation focuses on theoretical and empirical evaluations performed to determine the feasibility of using a full suit, variable emissivity radiator architecture for space suit thermal control. Operational envelopes are described that show where a given environment and/or metabolic load combination may or may not be supported by the evaluated thermal architecture. Key integration considerations and guidelines include determining allowable thermal environments, defining skin-to-radiator heat transfer properties, and evaluating required electrochromic performance properties. Analysis also considered the impacts of dynamic environmental changes and the architecture's extensibility to EVA on the Martian surface. At the conclusion of this work, the full suit, variable emissivity

  10. Complex dynamics

    CERN Document Server

    Carleson, Lennart

    1993-01-01

    Complex dynamics is today very much a focus of interest. Though several fine expository articles were available, by P. Blanchard and by M. Yu. Lyubich in particular, until recently there was no single source where students could find the material with proofs. For anyone in our position, gathering and organizing the material required a great deal of work going through preprints and papers and in some cases even finding a proof. We hope that the results of our efforts will be of help to others who plan to learn about complex dynamics and perhaps even lecture. Meanwhile books in the field a. re beginning to appear. The Stony Brook course notes of J. Milnor were particularly welcome and useful. Still we hope that our special emphasis on the analytic side will satisfy a need. This book is a revised and expanded version of notes based on lectures of the first author at UCLA over several \\Vinter Quarters, particularly 1986 and 1990. We owe Chris Bishop a great deal of gratitude for supervising the production of cour...

  11. Geography and Dynamics of the Industries Processing Raw Materials of Animal Origin in the Villages of Kharkiv Region during the NEP

    Directory of Open Access Journals (Sweden)

    A. Lapchenko

    2016-02-01

    Full Text Available Background research related to the lack of researches in the given topic historiography. Territorial boundaries cover a large region — Kharkiv region, which until 1925 largely coincide with the boundaries of Kharkov province. And in 1925, it was divided into several provinces — Kharkov, Sumy, Kupiansk, Izyumskogo, Romney. The chronological boundaries article dated from 1921–1929’s, during which was implemented new economic polityka.Osnovnu attention paid to the article features geographically-sectoral design small-scale production of animal products in the region in 20 years of the twentieth century. On the basis of the detected and studied complex of sources the author analyzes the source base peasant industries in Kharkiv in this period. Found total number of farmers who were engaged in crafts processing animal products. Also revealed the specific industry Kharkov peasantry during nepu. Isnuvav number of factors that pushed the peasant engage in crafts: surplus agricultural products and raw materials; meet a wide range of numerous industrial, domestic and cultural needs; urgent need to replenish the family budget; surplus labor; free time from agricultural work (especially in winter and others. The development of rural industries processing animal products in the years 1921–1929 in the Kharkiv region characterized by strength and diversity. Village artisans representing an original way of small private commodity production. Basically crafts processing animal products involved in two socio-professional groups: lone artisan and peasant host of crafts. The social basis of industrial employment accounted malozemelni without sowing without Traction economy, which crafts were an important source of household income. The attention is focused on characteristic features of the state policy on «small business » peasants. Attention is paid to co-operation and effects of these industries on the further development rozvytok. Kooperatyvna form

  12. On conservation laws in geometrically nonlinear elasto-dynamic field of non-homogenous materials%论非均匀材料几何非线性弹性动力学场的守恒律

    Institute of Scientific and Technical Information of China (English)

    施伟辰; 高庆海; 李欢欢

    2006-01-01

    对基于Lagrange框架描述的非均匀弹性材料的Lagrange泛函应用Noether原理,开展材料的几何非线性弹性动力学场守恒律的研究,并给出其物质空间守恒律与物质平衡定律之间关系的清晰图景.研究发现,质量密度和弹性系数需满足一组一阶线性偏微分方程,该组方程不但包含来自Newton力学时-空观的全部时-空对称变换,而且控制着材料物质空间守恒律的存在性和存在的形式.特别需指出的是,惯性坐标系的平移和旋转是Lagrange泛函的对称变换,这些对称变换可导致均匀材料的物质空间守恒律和非均匀材料的物质平衡定律,但是时-空坐标的标度改变并不是对称变换.然而,若质量密度和弹性系数满足由上述方程简化而来的一组特殊的一阶线性偏微分方程,则时-空坐标的标度改变可成为Lagrange泛函的对称变换并导致相关守恒律的存在,但此时与该守恒律关联的物质平衡定律仍然不存在.为构造适合力学分析的功能梯度材料的物质空间守恒律,进行了质量密度和弹性系数需满足的方程的应用研究.对于粘合于基底的功能梯度材料层,给出全部非平凡的物质空间守恒律.%By applying Noether's theorem to the Lagrangian density of non-homogenous elastic materials in the so-called Lagrangian framework, conservation laws in geometrically nonlinear elasto-dynamic field have been studied, and a clear picture of relations between the conservation laws in material space and the material balance laws is given. It is found that the mass density and Lamé's moduli have to satisfy a set of first-order linear partial differential equations, which contain all the symmetry-transformations of space-time based on Newtonian viewpoint of mechanics. The existence and existent forms of conservation laws in material space are governed by these equations. Especially, translation and rotation of coordinates are symmetry

  13. Optical materials

    International Nuclear Information System (INIS)

    Poker, D.B.; Ortiz, C.

    1989-01-01

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

  14. Dynamical Systems Conference

    CERN Document Server

    Gils, S; Hoveijn, I; Takens, F; Nonlinear Dynamical Systems and Chaos

    1996-01-01

    Symmetries in dynamical systems, "KAM theory and other perturbation theories", "Infinite dimensional systems", "Time series analysis" and "Numerical continuation and bifurcation analysis" were the main topics of the December 1995 Dynamical Systems Conference held in Groningen in honour of Johann Bernoulli. They now form the core of this work which seeks to present the state of the art in various branches of the theory of dynamical systems. A number of articles have a survey character whereas others deal with recent results in current research. It contains interesting material for all members of the dynamical systems community, ranging from geometric and analytic aspects from a mathematical point of view to applications in various sciences.

  15. Strategic Materials

    National Research Council Canada - National Science Library

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

    2006-01-01

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

  16. Computational materials science: Nanoscale plasticity

    DEFF Research Database (Denmark)

    Jacobsen, Karsten Wedel; Schiøtz, Jakob

    2002-01-01

    How does plastic deformation of polycrystalline materials with grain sizes less than 100 nm look at the atomic scale? A large-scale molecular dynamics simulation of nanocrystalline alluminium reveals some surprising behaviour.......How does plastic deformation of polycrystalline materials with grain sizes less than 100 nm look at the atomic scale? A large-scale molecular dynamics simulation of nanocrystalline alluminium reveals some surprising behaviour....

  17. Dynamic probabilistic material flow analysis of nano-SiO2, nano iron oxides, nano-CeO2, nano-Al2O3, and quantum dots in seven European regions.

    Science.gov (United States)

    Wang, Yan; Nowack, Bernd

    2018-04-01

    Static environmental exposure assessment models based on material flow analysis (MFA) have previously been used to estimate flows of engineered nanomaterials (ENMs) to the environment. However, such models do not account for changes in the system behavior over time. Dynamic MFA used in this study includes the time-dependent development of the modelling system by considering accumulation of ENMs in stocks and the environment, and the dynamic release of ENMs from nano-products. In addition, this study also included regional variations in population, waste management systems, and environmental compartments, which subsequently influence the environmental release and concentrations of ENMs. We have estimated the flows and release concentrations of nano-SiO 2 , nano-iron oxides, nano-CeO 2 , nano-Al 2 O 3 , and quantum dots in the EU and six geographical sub-regions in Europe (Central Europe, Northern Europe, Southern Europe, Eastern Europe, South-eastern Europe, and Switzerland). The model predicts that a large amount of ENMs are accumulated in stocks (not considering further transformation). For example, in the EU 2040 Mt of nano-SiO 2 are stored in the in-use stock, 80,400 tonnes have been accumulated in sediments and 65,600 tonnes in natural and urban soil from 1990 to 2014. The magnitude of flows in waste management processes in different regions varies because of differences in waste handling. For example, concentrations in landfilled waste are lowest in South-eastern Europe due to dilution by the high amount of landfilled waste in the region. The flows predicted in this work can serve as improved input data for mechanistic environmental fate models and risk assessment studies compared to previous estimates using static models. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Computational materials design

    International Nuclear Information System (INIS)

    Snyder, R.L.

    1999-01-01

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

  19. Modeling of materials supply, demand and prices

    Science.gov (United States)

    1982-01-01

    The societal, economic, and policy tradeoffs associated with materials processing and utilization, are discussed. The materials system provides the materials engineer with the system analysis required for formulate sound materials processing, utilization, and resource development policies and strategies. Materials system simulation and modeling research program including assessments of materials substitution dynamics, public policy implications, and materials process economics was expanded. This effort includes several collaborative programs with materials engineers, economists, and policy analysts. The technical and socioeconomic issues of materials recycling, input-output analysis, and technological change and productivity are examined. The major thrust areas in materials systems research are outlined.

  20. Materials Chemistry

    CERN Document Server

    Fahlman, Bradley D

    2011-01-01

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

  1. Material-controlled dynamic vacuum insulation

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1996-10-08

    A compact vacuum insulation panel is described comprising a chamber enclosed by two sheets of metal, glass-like spaces disposed in the chamber between the sidewalls, and a high-grade vacuum in the chamber includes apparatus and methods for enabling and disabling, or turning ``on`` and ``off`` the thermal insulating capability of the panel. One type of enabling and disabling apparatus and method includes a metal hydride for releasing hydrogen gas into the chamber in response to heat, and a hydrogen grate between the metal hydride and the chamber for selectively preventing and allowing return of the hydrogen gas to the metal hydride. Another type of enabling and disabling apparatus and method includes a variable emissivity coating on the sheets of metal in which the emissivity is controllably variable by heat or electricity. Still another type of enabling and disabling apparatus and method includes metal-to-metal contact devices that can be actuated to establish or break metal-to-metal heat paths or thermal short circuits between the metal sidewalls. 25 figs.

  2. Recent developments in dynamic testing of materials

    Directory of Open Access Journals (Sweden)

    Seidt J.D.

    2012-08-01

    Full Text Available Three new testing configurations that have been developed since the last DYMAT conference in 2009 are presented. The first is high strain rate testing of Kevlar cloth and Kevlar yarn in a tensile Split Hopkinson Bar (SHB apparatus. The Kevlar cloth/yarn is attached to the bars by specially designed adaptors that keep the impedance constant. In addition to determining the specimen’s stress and strain from the recorded waves in the bars the deformations are also measured with Digital Image Correlation (DIC. The second testing configuration is a high strain rate shear test for sheet metal. The experiment is done by using a flat notched specimen in a tensile SHB apparatus. The shear strain is measured using DIC within the notch and on the boundary. The third development is a compression apparatus for testing at intermediate strain rates ranging from 20 s−1 to 200 s−1. The apparatus is a combination of a hydraulic actuator and a compression SHB. The stress in the specimen is determined from the stress wave in a very long transmitter bar and the strain and strain rate is determined by using DIC. The results show clean stress strain curves (no ringing.

  3. Peri-dynamics

    International Nuclear Information System (INIS)

    Littlewood, D.

    2015-01-01

    Peri-dynamics, a nonlocal extension of continuum mechanics, is a natural framework for capturing constitutive response and modelling pervasive material failure and fracture. Unlike classical approaches incorporating partial derivatives, the peri-dynamic governing equations utilise integral expressions that remain valid in the presence of discontinuities such as cracks. The mathematical theory of peri-dynamics unifies the mechanics of continuous media, cracks, and discrete particles. The result is a consistent framework for capturing a wide range of constitutive responses, including inelasticity, in combination with robust material failure laws. Peri-dynamics has been implemented in a number of computational simulation codes, including the open source code Peridigm and the Sierra/SolidMechanics analysis code at Sandia National Laboratories. (author)

  4. A comparison of the lattice discrete particle method to the finite-element method and the K&C material model for simulating the static and dynamic response of concrete.

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Jovanca J.; Bishop, Joseph E.

    2013-11-01

    This report summarizes the work performed by the graduate student Jovanca Smith during a summer internship in the summer of 2012 with the aid of mentor Joe Bishop. The projects were a two-part endeavor that focused on the use of the numerical model called the Lattice Discrete Particle Model (LDPM). The LDPM is a discrete meso-scale model currently used at Northwestern University and the ERDC to model the heterogeneous quasi-brittle material, concrete. In the first part of the project, LDPM was compared to the Karagozian and Case Concrete Model (K&C) used in Presto, an explicit dynamics finite-element code, developed at Sandia National Laboratories. In order to make this comparison, a series of quasi-static numerical experiments were performed, namely unconfined uniaxial compression tests on four varied cube specimen sizes, three-point bending notched experiments on three proportional specimen sizes, and six triaxial compression tests on a cylindrical specimen. The second part of this project focused on the application of LDPM to simulate projectile perforation on an ultra high performance concrete called CORTUF. This application illustrates the strengths of LDPM over traditional continuum models.

  5. Knowledge-based metals & materials

    OpenAIRE

    Sasson, Amir

    2011-01-01

    This study presents the Norwegian metal and material industry (defined as all metal and material related firms located in Norway, regardless of ownership) and evaluates the industry according to the underlying dimensions of a global knowledge hub - cluster attractiveness, education attractiveness, talent attractiveness, R&D and innovation attractiveness, ownership attractiveness, environmental attractiveness and cluster dynamics.

  6. Contrast Materials

    Science.gov (United States)

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

  7. Dirac materials

    OpenAIRE

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

    2014-01-01

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

  8. Magnetic Materials

    Science.gov (United States)

    Spaldin, Nicola A.

    2003-04-01

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

  9. Mechanics of moving materials

    CERN Document Server

    Banichuk, Nikolay; Neittaanmäki, Pekka; Saksa, Tytti; Tuovinen, Tero

    2014-01-01

    This book deals with theoretical aspects of modelling the mechanical behaviour of manufacturing, processing, transportation or other systems in which the processed or supporting material is travelling through the system. Examples of such applications include paper making, transmission cables, band saws, printing presses, manufacturing of plastic films and sheets, and extrusion of aluminium foil, textiles and other materials.   The work focuses on out-of-plane dynamics and stability analysis for isotropic and orthotropic travelling elastic and viscoelastic materials, with and without fluid-structure interaction, using analytical and semi-analytical approaches.  Also topics such as fracturing and fatigue are discussed in the context of moving materials. The last part of the book deals with optimization problems involving physical constraints arising from the stability and fatigue analyses, including uncertainties in the parameters.   The book is intended for researchers and specialists in the field, providin...

  10. Designing Biomimetic, Dissipative Material Systems

    Energy Technology Data Exchange (ETDEWEB)

    Balazs, Anna C. [Univ. of Pittsburgh, PA (United States). Chemical Engineering Dept.; Whitesides, George M. [Harvard Univ., Cambridge, MA (United States). Dept. of Chemistry and Chemical Biology; Brinker, C. Jeffrey [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Chemical and Nuclear Engineering. Dept. of Chemistry. Dept. of Molecular Genetics and Microbiology. Center for Micro-Engineered Materials; Aranson, Igor S. [UChicago, LLC., Argonne, IL (United States); Chaikin, Paul [New York Univ. (NYU), NY (United States). Dept. of Physics; Dogic, Zvonimir [Brandeis Univ., Waltham, MA (United States). Dept. of Physics; Glotzer, Sharon [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Chemical Engineering. Dept. of Materials Science and Engineering. Dept. of Macromolecular Science and Engineering Physics; Hammer, Daniel [Univ. of Pennsylvania, Philadelphia, PA (United States). School of Engineering and Applied Science; Irvine, Darrell [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Dept. of Materials Science and Engineering and Biological Engineering; Little, Steven R. [Univ. of Pittsburgh, PA (United States). Chemical Engineering Dept.; Olvera de la Cruz, Monica [Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science and Engineering; Parikh, Atul N. [Univ. of California, Davis, CA (United States). Dept. of Biomedical Engineering. Dept. of Chemical Engineering and Materials Science; Stupp, Samuel [Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science and Engineering. Dept. of Chemistry. Dept. of Medicine. Dept. of Biomedical Engineering; Szostak, Jack [Harvard Univ., Cambridge, MA (United States). Dept. of Chemistry and Chemical Biology

    2016-01-21

    Throughout human history, new materials have been the foundation of transformative technologies: from bronze, paper, and ceramics to steel, silicon, and polymers, each material has enabled far-reaching advances. Today, another new class of materials is emerging—one with both the potential to provide radically new functions and to challenge our notion of what constitutes a “material”. These materials would harvest, transduce, or dissipate energy to perform autonomous, dynamic functions that mimic the behaviors of living organisms. Herein, we discuss the challenges and benefits of creating “dissipative” materials that can potentially blur the boundaries between living and non-living matter.

  11. Composite materials

    International Nuclear Information System (INIS)

    Sambrook, D.J.

    1976-01-01

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

  12. Aerospace materials and material technologies

    CERN Document Server

    Wanhill, R

    2017-01-01

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

  13. Materiality, Practice and Body

    DEFF Research Database (Denmark)

    Johansen, Stine Liv; Skovbjerg-Karoff, Helle

    2009-01-01

    In order to understand the interaction between human and technology, the relationship must be emphasized as a triangulation between materiality, body and practice. By introducing play situations from a just finished empirical study in three bigger cities in Denmark, this paper will address...... the interplay from the human‟s point of view, as a body doing a certain practice, which is constantly produced by taking approaches which comes from phenomenology and practice theory. We introduce aspects of play understood as a dynamic between materiality, body and practice with the goal of inspiring not only...

  14. Materials Discovery | Materials Science | NREL

    Science.gov (United States)

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

  15. Properties of materials

    CERN Document Server

    Kelly, P F

    2014-01-01

    Materials 'Tidings' of Rigidity's Breakdown Elastic Properties of Solids Elastic Solids in Series and Parallel Fluid Statics Eureka! Fluid Dynamics: Flux Bernoulli's Equation No Confusion, It's Just Diffusion Baby, It's Viscous Outside Gas Gas Gas Through the Earth and Back Introduction to Simple Harmonic Oscillation SHO-Time Springs in Series and Parallel SHO: Kinematics, Dynamics, and Energetics Damped Oscillation: Qualitative Damped Oscillation: Explicitly Forced Oscillations Impedance and Power Resonance The First Wave Wave Dynamics and Phenomenology Linear Superposition of Waves Linear Superposition of Rightmoving Harmonic Waves Standing Waves Transverse Waves: Speed and Energetics Speed of Longitudinal Waves Energy Content of Longitudinal Waves Inhomogeneous Media Doppler Shifts Huygens' Principle, Interference, and Diffraction Say Hello, Wave Goodbye Optics Mirror Mirror Refraction Through a Glass Darkly Temperature and Thermometry Heat Convective and Conductive Heat Flow Radiative Heat Flow More Radia...

  16. Development of a dynamic in vitro model of a stented blood vessel to evaluate the effects of stent strut material selection and surface coating on smooth muscle cell response

    Science.gov (United States)

    Winn, Bradley Huegh

    formation of this new tissue, primarily consisting of VSMCs of the synthetic phenotype and their subsequent extracellular matrix, is the sole causation of in-stent restenosis since the stent serves to prevent elastic recoil and negative remodeling. This doctoral research program is focused on endovascular stent biomaterials science and engineering. Overall, this doctoral project is founded on the hypothesis that smooth muscle cell hyperplasia, as an important causative factor for vascular restenosis following endovascular stent deployment, is triggered by the various effects of stent strut contact on the vessel wall including contact forces and material biocompatibility. In this program, a dynamic in vitro model of a stented blood vessel aimed at evaluating the effect of stent strut material selection, and surface coating on smooth muscle cell response was developed. The in vitro stented artery model was validated through the proliferation of VSMC in contact with stent struts. Additionally, it was demonstrated that, with respect to known biocompatible materials such as Nitinol and 316L stainless steel, DNA synthesis and alpha-actin expression, as indicators of VSMC phenotype, are independent of stent material composition. Furthermore, hydroxyapatite was shown to be a biocompatible stent surface coating with acceptable post-strain integrity. This coating was shown in a feasibility study to be capable of serving as a favorable drug delivery platform able to reliably deliver locally therapeutic doses of bisphosphonates, such as alendronate, to control VSMC proliferation in an in vitro model of a stented blood vessel. This stent coating/drug combination may be effective for reducing restenosis as a result of VSMC hyperplasia in vivo.

  17. System dynamics

    International Nuclear Information System (INIS)

    Kim, Do Hun; Mun, Tae Hun; Kim, Dong Hwan

    1999-02-01

    This book introduces systems thinking and conceptual tool and modeling tool of dynamics system such as tragedy of single thinking, accessible way of system dynamics, feedback structure and causal loop diagram analysis, basic of system dynamics modeling, causal loop diagram and system dynamics modeling, information delay modeling, discovery and application for policy, modeling of crisis of agricultural and stock breeding products, dynamic model and lesson in ecosystem, development and decadence of cites and innovation of education forward system thinking.

  18. Proteomics analysis of cytokine-induced dysfunction and death in insulin-producing INS-1E cells: new insights into the pathways involved

    DEFF Research Database (Denmark)

    D'Hertog, Wannes; Overbergh, Lut; Hansen, Kasper Lage

    2007-01-01

    points (1, 4, and 24 h of cytokine exposure) revealed that the major changes were taking place only after 24 h. At this time point 158 proteins were altered in expression (4.1%, n = 4, p ...-cell attack. The aim of the present study was to analyze protein changes in insulin-producing INS-1E cells exposed to inflammatory cytokines in vitro using two-dimensional DIGE. Within two different pH ranges we observed 2214 +/- 164 (pH 4-7) and 1641 +/- 73 (pH 6-9) spots. Analysis at three different time...... reticulum and oxidative stress/defense. We investigated the interactions of these proteins and discovered a significant interaction network (p analysis suggests that proteins of different pathways act coordinately in a beta-cell dysfunction...

  19. Nano Materials

    International Nuclear Information System (INIS)

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

    2006-02-01

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

  20. Material Systems

    DEFF Research Database (Denmark)

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

    2009-01-01

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

  1. Material focus

    DEFF Research Database (Denmark)

    Sokoler, Tomas; Vallgårda, Anna K. A.

    2009-01-01

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

  2. Materializing Ethnography

    OpenAIRE

    Geismar, H.; Horst, H. A.

    2004-01-01

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

  3. [Effect of Zhenwu Tang on regulating of "AVP-V2R-AQP2" pathway in NRK-52E cells].

    Science.gov (United States)

    Zhou, Xiao-Jie; Bao, Yu-Ting; Chen, Hong-Shu; Xuan, Ling; Chen, Xue-Ming; Zhang, Jie-Ying; Yang, Yuan-Xiao; Li, Chang-Yu

    2018-02-01

    This study was aimed to investigate the effect and mechanism of Zhenwu Tang on AVP-V2R-AQP2 pathway in NRK-52E cells in vitro . Forty eight male SD rats were randomly divided into eight groups with 6 animals in each group. Distilled water or 22.68 g·kg⁻¹·d⁻¹ Zhenwu Tang(calculated by raw drug dosage meter) was given by gavage. Blood samples were collected by cardiac puncture, and the medicated serum was centrifuged from the blood by 3 000 r·min⁻¹. NRK-52E cells were treated with different medicated serum or dDAVP. The condition of cell proliferation was detected by RTCA. The distribution of V2R and AQP2 in cells were detected by immunofluorescence. The expression of V2R, PKA and AQP2 were detected by Western blot and AQP2 mRNA level was detected by real-time PCR. Results showed that the level of AQP2 mRNA( P Tang medicated serum for 24 h were significantly higher than that of normal rat serum group. And the expression level of V2R, p-AQP2 and AQP2( P Tang medicated serum could increase the expression level of V2R, PKA and AQP2 which exist in AVP-V2R-AQP2 pathway in NRK-52E, and there is synergistic effect between Zhenwu Tang medicated serum and dDAVP. So the pathway of AVP-V2R-AQP2 may be one of the mechanism for which Zhenwu Tang regulate balance of water transportation. Copyright© by the Chinese Pharmaceutical Association.

  4. Melatonin-Mediated Intracellular Insulin during 2-Deoxy-d-glucose Treatment Is Reduced through Autophagy and EDC3 Protein in Insulinoma INS-1E Cells

    Directory of Open Access Journals (Sweden)

    Han Sung Kim

    2016-01-01

    Full Text Available 2-DG triggers glucose deprivation without altering other nutrients or metabolic pathways and then activates autophagy via activation of AMPK and endoplasmic reticulum (ER stress. We investigated whether 2-DG reduced intracellular insulin increased by melatonin via autophagy/EDC3 in insulinoma INS-1E cells. p-AMPK and GRP78/BiP level were significantly increased by 2-DG in the presence/absence of melatonin, but IRE1α level was reduced in 2-DG treatment. Levels of p85α, p110, p-Akt (Ser473, Thr308, and p-mTOR (Ser2481 were also significantly reduced by 2-DG in the presence/absence of melatonin. Mn-SOD increased with 2-DG plus melatonin compared to groups treated with/without melatonin alone. Bcl-2 was decreased and Bax increased with 2-DG plus melatonin. LC3II level increased with 2-DG treatment in the presence/absence of melatonin. Intracellular insulin production increased in melatonin plus 2-DG but reduced in treatment with 2-DG with/without melatonin. EDC3 was increased by 2-DG in the presence/absence of melatonin. Rapamycin, an mTOR inhibitor, increased GRP78/BiP and EDC3 levels in a dose-dependent manner and subsequently resulted in a decrease in intracellular production of insulin. These results suggest that melatonin-mediated insulin synthesis during 2-DG treatment involves autophagy and EDC3 protein in rat insulinoma INS-1E cells and subsequently results in a decrease in intracellular production of insulin.

  5. Materials characterisation

    International Nuclear Information System (INIS)

    Azali Muhammad

    2005-01-01

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

  6. New materials

    International Nuclear Information System (INIS)

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

    1992-01-01

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

  7. Materials science

    International Nuclear Information System (INIS)

    2002-01-01

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

  8. Composite material

    Science.gov (United States)

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

    2012-02-07

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

  9. Materials science

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

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

  10. Touching Materiality

    DEFF Research Database (Denmark)

    Rasmussen, Lisa Rosén

    2012-01-01

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

  11. Materials accounting at Los Alamos National Laboratory

    International Nuclear Information System (INIS)

    Erkkila, B.H.; Roberts, N.J.

    1989-01-01

    This presentation gives an overview of the accounting system used at the Los Alamos National Laboratory by the Los Alamos Nuclear Material Accounting and Safeguards System (MASS). This system processes accounting data in real time for bulk materials, discrete items, and materials undergoing dynamic processing. The following topics are covered in this chapter: definitions; nuclear material storage; nuclear material storage; computer system; measurement control program; inventory differences; and current programs and future plans

  12. Fluid dynamics

    CERN Document Server

    Ruban, Anatoly I

    This is the first book in a four-part series designed to give a comprehensive and coherent description of Fluid Dynamics, starting with chapters on classical theory suitable for an introductory undergraduate lecture course, and then progressing through more advanced material up to the level of modern research in the field. The present Part 1 consists of four chapters. Chapter 1 begins with a discussion of Continuum Hypothesis, which is followed by an introduction to macroscopic functions, the velocity vector, pressure, density, and enthalpy. We then analyse the forces acting inside a fluid, and deduce the Navier-Stokes equations for incompressible and compressible fluids in Cartesian and curvilinear coordinates. In Chapter 2 we study the properties of a number of flows that are presented by the so-called exact solutions of the Navier-Stokes equations, including the Couette flow between two parallel plates, Hagen-Poiseuille flow through a pipe, and Karman flow above an infinite rotating disk. Chapter 3 is d...

  13. PREFACE: Dynamics of wetting Dynamics of wetting

    Science.gov (United States)

    Grest, Gary S.; Oshanin, Gleb; Webb, Edmund B., III

    2009-11-01

    of their continuum model via comparison with molecular dynamics simulations.Bertrand et al use large scale molecular dynamics simulations to examine fundamental questions about wetting dynamics and how they depend upon interactions between a liquid drop and solid substrate; in particular, atomic scale mechanisms directly associated with the molecular kinetic theory of wetting are observed and quantified. Sun et al explore, by molecular dynamics simulations, atomistic mechanisms of high temperature contact line advancement for a rapidly spreading liquid droplet. Starov et al discuss general aspects of surface forces and wetting phenomena, while Courbin et al present anoverview of diverse dynamical processes ranging from inertial spreading to viscous imbibition. Mukhopadhyay et al examine the effect of Marangoni and centrifugal forces on the wetting dynamics of thin liquid films and drops. Willis et al analyze an enhanced droplet spreading due to thermal fluctuations. How wetting and contact line dynamics depend upon the complexity of the structure in the liquid is interesting both academically and technologically; Delabre et al illustrate this with a study of wetting of liquid crystals and the role of molecular scale organization. In addition, Mechkov et al explore this realm by studying post-Tanner spreading for nematic droplets and, in general, post-Tanner spreading of liquid droplets governed by the contact line-tension effects. Liang et al focus on spreading dynamics of power-law fluid droplets, while Wei et al discuss dynamics of wetting in viscous Newtonian and non-Newtonian fluids. Yin et al discuss an important issue of reactive wetting in metal-metal systems. We hope that the articles gathered here will permit readers to understand the wide range of condensed matter systems impacted by wetting kinetics and the many complicating factors that emerge in describing contact line dynamics for realistic materials. We wish to thank all the contributing authors for

  14. Dynamical Languages

    Science.gov (United States)

    Xie, Huimin

    The following sections are included: * Definition of Dynamical Languages * Distinct Excluded Blocks * Definition and Properties * L and L″ in Chomsky Hierarchy * A Natural Equivalence Relation * Symbolic Flows * Symbolic Flows and Dynamical Languages * Subshifts of Finite Type * Sofic Systems * Graphs and Dynamical Languages * Graphs and Shannon-Graphs * Transitive Languages * Topological Entropy

  15. Semiclassical dynamics

    International Nuclear Information System (INIS)

    Balazs, N.L.

    1979-01-01

    It is pointed out that in semiclassical dynamics one is encouraged to study the evolution of those curves in phase space which classically represent ensembles corresponding to wave functions. It is shown that the fixed points generate new time scales so that for times longer than the critical times, quantum dynamics will profoundly differ from classical dynamics. (P.L.)

  16. Nuclear materials

    International Nuclear Information System (INIS)

    1996-01-01

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

  17. Composite Materials

    DEFF Research Database (Denmark)

    Nielsen, Lauge Fuglsang

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

  18. Hazardous materials

    Science.gov (United States)

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

  19. Utopian Materialities

    DEFF Research Database (Denmark)

    Elgaard-Jensen, Torben

    2004-01-01

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

  20. Propulsion materials

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-01-01

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

  1. Encountering Materiality

    DEFF Research Database (Denmark)

    Svabo, Connie

    2016-01-01

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

  2. Background Material

    DEFF Research Database (Denmark)

    Zandersen, Marianne; Hyytiäinen, Kari; Saraiva, Sofia

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

  3. Impact Compaction of a Granular Material

    Science.gov (United States)

    Fenton, Gregg; Asay, Blaine; Todd, Steve; Grady, Dennis

    2017-06-01

    The dynamic behavior of granular materials has importance to a variety of engineering applications. Although, the mechanical behavior of granular materials have been studied extensively for several decades, the dynamic behavior of these materials remains poorly understood. High-quality experimental data are needed to improve our general understanding of granular material compaction physics. This paper describes how an instrumented plunger impact system can be used to measure the compaction process for granular materials at high and controlled strain rates and subsequently used for computational modelling. The experimental technique relies on a gas-gun driven plunger system to generate a compaction wave through a volume of granular material. This volume of material has been redundantly instrumented along the bed length to track the progression of the compaction wave, and the piston displacement is measured with Photon Doppler Velocimetry (PDV). Using the gathered experimental data along with the initial material tap density, a granular material equation of state can be determined.

  4. Dynamics of aesthetic appreciation

    Science.gov (United States)

    Carbon, Claus-Christian

    2012-03-01

    Aesthetic appreciation is a complex cognitive processing with inherent aspects of cold as well as hot cognition. Research from the last decades of empirical has shown that evaluations of aesthetic appreciation are highly reliable. Most frequently, facial attractiveness was used as the corner case for investigating aesthetic appreciation. Evaluating facial attractiveness shows indeed high internal consistencies and impressively high inter-rater reliabilities, even across cultures. Although this indicates general and stable mechanisms underlying aesthetic appreciation, it is also obvious that our taste for specific objects changes dynamically. Aesthetic appreciation on artificial object categories, such as fashion, design or art is inherently very dynamic. Gaining insights into the cognitive mechanisms that trigger and enable corresponding changes of aesthetic appreciation is of particular interest for research as this will provide possibilities to modeling aesthetic appreciation for longer durations and from a dynamic perspective. The present paper refers to a recent two-step model ("the dynamical two-step-model of aesthetic appreciation"), dynamically adapting itself, which accounts for typical dynamics of aesthetic appreciation found in different research areas such as art history, philosophy and psychology. The first step assumes singular creative sources creating and establishing innovative material towards which, in a second step, people adapt by integrating it into their visual habits. This inherently leads to dynamic changes of the beholders' aesthetic appreciation.

  5. Dislocation Dynamics During Plastic Deformation

    CERN Document Server

    Messerschmidt, Ulrich

    2010-01-01

    The book gives an overview of the dynamic behavior of dislocations and its relation to plastic deformation. It introduces the general properties of dislocations and treats the dislocation dynamics in some detail. Finally, examples are described of the processes in different classes of materials, i.e. semiconductors, ceramics, metals, intermetallic materials, and quasicrystals. The processes are illustrated by many electron micrographs of dislocations under stress and by video clips taken during in situ straining experiments in a high-voltage electron microscope showing moving dislocations. Thus, the users of the book also obtain an immediate impression and understanding of dislocation dynamics.

  6. Transformative Dynamics in Detailed Planning

    DEFF Research Database (Denmark)

    Quitzau, Maj-Britt; Poulsen, Naja; Gustavsson, Ted

    Many of the ambitious sustainable strategies on how to integrate sustainable solutions expressed in urban development projects do not become materialized in the urban design. This paper aims to uncover the transformative dynamics involved in this translation process of materializing the formulate...

  7. The Dynamic Earth: Recycling Naturally!

    Science.gov (United States)

    Goldston, M. Jenice; Allison, Elizabeth; Fowler, Lisa; Glaze, Amanda

    2013-01-01

    This article begins with a thought-provoking question: What do you think of when you hear the term "recycle?" Many think about paper, glass, aluminum cans, landfills, and reducing waste by reusing some of these materials. How many of us ever consider the way the systems of Earth dynamically recycle its materials? In the following…

  8. Introduction Of Computational Materials Science

    International Nuclear Information System (INIS)

    Lee, Jun Geun

    2006-08-01

    This book gives, descriptions of computer simulation, computational materials science, typical three ways of computational materials science, empirical methods ; molecular dynamics such as potential energy, Newton's equation of motion, data production and analysis of results, quantum mechanical methods like wave equation, approximation, Hartree method, and density functional theory, dealing of solid such as pseudopotential method, tight-binding methods embedded atom method, Car-Parrinello method and combination simulation.

  9. Imidazoline NNC77-0074 stimulates Ca2+-evoked exocytosis in INS-1E cells by a phospholipase A2-dependent mechanism

    DEFF Research Database (Denmark)

    Olsen, Hervør L; Nørby, Peder L; Høy, Marianne

    2003-01-01

    We have previously demonstrated that the novel imidazoline compound (+)-2-(2-(4,5-dihydro-1H-imidazol-2-yl)-thiopene-2-yl-ethyl)-pyridine (NNC77-0074) increases insulin secretion from pancreatic beta-cells by stimulation of Ca(2+)-dependent exocytosis. Using capacitance measurements, we now show...... that NNC77-0074 stimulates exocytosis in clonal INS-1E cells. NNC77-0074-stimulated exocytosis was antagonised by the cytoplasmic phospholipase A(2) (cPLA(2)) inhibitors ACA and AACOCF(3) and in cells treated with antisense oligonucleotide against cPLA(2)alpha. NNC77-0074-evoked insulin secretion...... was likewise inhibited by ACA, AACOCF(3), and cPLA(2)alpha antisense oligonucleotide treatment. In pancreatic islets NNC77-0074 stimulated PLA(2) activity. We propose that cPLA(2)alpha plays an important role in the regulation of NNC77-0074-evoked exocytosis in insulin secreting beta-cells....

  10. Detection of a deuterium isotope effect in di- and trisubstituted alkylphenylnitrosoureas. An SCE study in Chinese hamster V79-E cells.

    Science.gov (United States)

    Thust, R; Mendel, J; Bach, B; Schwarz, H

    1985-06-01

    The genotoxicity of 1-methyl-3-phenyl-1-nitrosourea (MPNU), 1-methyl-3-(p-chlorophenyl)-1-nitrosourea (C1-MPNU), 1-ethyl-3-phenyl-1-nitrosourea (EPNU), 1,3-dimethyl-3-phenyl-1-nitrosourea (DMPNU) and their derivatives substituted by deuterium in different positions was studied using sister chromatid exchange (SCE) induction in Chinese hamster V79-E cells. Deuterium substitution in the 1-methyl group of MPNU (MPNU-d3) and C1-MPNU (C1-MPNU-d3) diminished the SCE-inducing capacity by 20-30% and by 30-40% in DMPNU (DMPNU-d3B). There was no altered SCE activity detected when the phenyl group of MPNU (MPNU-d5) or the 3-methyl group of DMPNU (DMPNU-d3A) was deuterium labeled. No isotope effect was detected in deuterated EPNU derivatives, presumably due to the instability of these compounds. It is surmised that the easier delocalization of the positive charge in the deuterated alkyl diazonium ion causes a diminished reactivity and therefore influences the type and amount of DNA alkylation. Furthermore, the experiments with DMPNU and its derivatives revealed that, in contrast to mono- and disubstituted nitrosoureas, the biological activities of these very stable trisubstituted nitrosoureas are strongly influenced by a serum factor in the culture fluid.

  11. Alkylarylnitrosoureas--stability in aqueous solution, partition coefficient, alkylating activity and its relationship to SCE induction in Chinese hamster V 79-E cells.

    Science.gov (United States)

    Mendel, J; Thust, R; Schwarz, H

    1982-01-01

    The alkylating activity, chemical stability in aqueous solution (pH 7.0; 37 degrees C), and partition coefficient (octanol/water) of the following compounds were determined: 1-methyl-3-phenyl-1-nitrosourea (MPNU), 1-ethyl-3-phenyl-1-nitrosourea (EPNU), 1-isopropyl-3-phenyl-1-nitrosourea (i-PrPNU), 1-methyl-3-(p-fluorophenyl)-1-nitrosourea (F-MPNU), 1-methyl-3-(p-chlorophenyl)-1-nitrosourea (Cl-MPNU), 1-methyl-3-(p-bromophenyl)-1-nitrosourea (Br-MPNU), 1,3-dimethyl-3-phenyl-1-nitrosourea (DMPNU), and 1-methyl-3-naphthyl-1-nitrosocarbamate (NCA). 1-Methyl-1-nitrosourea (MNU) and 1-ethyl-1-nitrosourea (ENU) were used for the comparison. THe rate of decomposition in aqueous solution is discussed concerning the influences of the substituents at the 1- and 3-N-atom. The mono- and disubstituted N-nitrosoureas showed a coarse correlation between alkylating activity and SCE induction in Chinese hamster V 79-E cells. On the other hand, this correlation is missing in the case of NCA, which is a potent SCE inducer despite relatively low alkylating activity. DMPNU is the strongest SCE inducer, but this compound shows a high stability in aqueous solution and, consequently, we were not able to detect an alkylating activity.

  12. Detection of a deuterium isotope effect in di- and trisubstituted alkylphenylnitrosoureas. An SCE study in Chinese hamster V79-E cells

    International Nuclear Information System (INIS)

    Thust, R.; Mendel, J.; Bach, B.; Schwarz, H.

    1985-01-01

    The genotoxicity of 1-methyl-3-phenyl-1-nitrosourea (MPNU), 1-methyl-3-(p-chlorophenyl)-1-nitrosourea (C1-MPNU), 1-ethyl-3-phenyl-1-nitrosourea (EPNU), 1,3-dimethyl-3-phenyl-1-nitrosourea (DMPNU) and their derivatives substituted by deuterium in different positions was studied using sister chromatid exchange (SCE) induction in Chinese hamster V79-E cells. Deuterium substitution in the 1-methyl group of MPNU (MPNU-d3) and C1-MPNU (C1-MPNU-d3) diminished the SCE-inducing capacity by 20-30% and by 30-40% in DMPNU (DMPNU-d3B). There was no altered SCE activity detected when the phenyl group of MPNU (MPNU-d5) or the 3-methyl group of DMPNU (DMPNU-d3A) was deuterium labeled. No isotope effect was detected in deuterated EPNU derivatives, presumably due to the instability of these compounds. It is surmised that the easier delocalization of the positive charge in the deuterated alkyl diazonium ion causes a diminished reactivity and therefore influences the type and amount of DNA alkylation. Furthermore, the experiments with DMPNU and its derivatives revealed that, in contrast to mono- and disubstituted nitrosoureas, the biological activities of these very stable trisubstituted nitrosoureas are strongly influenced by a serum factor in the culture fluid

  13. Hugoniot elastic limits and compression parameters for brittle materials

    International Nuclear Information System (INIS)

    Gust, W.H.

    1979-01-01

    The physical properties of brittle materials are of interest because of the rapidly expanding use of these material in high-pressure and shock wave techology, e.g., geophysics and explosive compaction as well as military applications. These materials are characterized by unusually high sonic velocities, have large dynamic impedances and exhibit large dynamic yield strengths

  14. Layered materials

    Science.gov (United States)

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

    2014-06-01

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

  15. Materials as stem cell regulators

    Science.gov (United States)

    Murphy, William L.; McDevitt, Todd C.; Engler, Adam J.

    2014-01-01

    The stem cell/material interface is a complex, dynamic microenvironment in which the cell and the material cooperatively dictate one another's fate: the cell by remodelling its surroundings, and the material through its inherent properties (such as adhesivity, stiffness, nanostructure or degradability). Stem cells in contact with materials are able to sense their properties, integrate cues via signal propagation and ultimately translate parallel signalling information into cell fate decisions. However, discovering the mechanisms by which stem cells respond to inherent material characteristics is challenging because of the highly complex, multicomponent signalling milieu present in the stem cell environment. In this Review, we discuss recent evidence that shows that inherent material properties may be engineered to dictate stem cell fate decisions, and overview a subset of the operative signal transduction mechanisms that have begun to emerge. Further developments in stem cell engineering and mechanotransduction are poised to have substantial implications for stem cell biology and regenerative medicine. PMID:24845994

  16. Moisture dynamics in building envelopes

    Energy Technology Data Exchange (ETDEWEB)

    Peuhkuri, R.

    2003-07-01

    The overall scope of this Thesis 'Moisture dynamics in building envelopes' has been to characterise how the various porous insulation materials investigated performed hygro thermally under conditions similar to those in a typical building envelope. As a result of the changing temperature and moisture conditions in the exterior weather and indoor climate the materials dynamically absorb and release moisture. The complexity of the impact of these conditions on the resulting moisture transport and content of the materials has been studied in this Thesis with controlled laboratory tests. (au)

  17. Introduction to cluster dynamics

    CERN Document Server

    Reinhard, Paul-Gerhard

    2008-01-01

    Clusters as mesoscopic particles represent an intermediate state of matter between single atoms and solid material. The tendency to miniaturise technical objects requires knowledge about systems which contain a ""small"" number of atoms or molecules only. This is all the more true for dynamical aspects, particularly in relation to the qick development of laser technology and femtosecond spectroscopy. Here, for the first time is a highly qualitative introduction to cluster physics. With its emphasis on cluster dynamics, this will be vital to everyone involved in this interdisciplinary subje

  18. Electronic materials

    CERN Document Server

    Kwok, H L

    2010-01-01

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

  19. Discrete dynamics versus analytic dynamics

    DEFF Research Database (Denmark)

    Toxværd, Søren

    2014-01-01

    For discrete classical Molecular dynamics obtained by the “Verlet” algorithm (VA) with the time increment h there exists a shadow Hamiltonian H˜ with energy E˜(h) , for which the discrete particle positions lie on the analytic trajectories for H˜ . Here, we proof that there, independent...... of such an analytic analogy, exists an exact hidden energy invariance E * for VA dynamics. The fact that the discrete VA dynamics has the same invariances as Newtonian dynamics raises the question, which of the formulations that are correct, or alternatively, the most appropriate formulation of classical dynamics....... In this context the relation between the discrete VA dynamics and the (general) discrete dynamics investigated by Lee [Phys. Lett. B122, 217 (1983)] is presented and discussed....

  20. Dynamic Stability of Maglev Systems,

    Science.gov (United States)

    1992-04-01

    AD-A259 178 ANL-92/21 Materials and Components Dynamic Stability of Technology Division Materials and Components Maglev Systems Technology Division...of Maglev Systems Y. Cai, S. S. Chen, and T. M. Mulcahy Materials and Components Technology Division D. M. Rote Center for Transportation Research...of Maglev System with L-Shaped Guideway ......................................... 6 3 Stability of M aglev System s