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Sample records for permeation properties bulk

  1. THE IMPACT OF PARTIAL CRYSTALLIZATION ON THE PERMEATION PROPERTIES BULK AMORPHOUS GLASS HYDROGEN SEPARATION MEMBRANES

    Brinkman, K; Paul Korinko, P; Thad Adams, T; Elise Fox, E; Arthur Jurgensen, A

    2008-11-25

    It is recognized that hydrogen separation membranes are a key component of the emerging hydrogen economy. A potentially exciting material for membrane separations are bulk metallic glass materials due to their low cost, high elastic toughness and resistance to hydrogen 'embrittlement' as compared to crystalline Pd-based membrane systems. However, at elevated temperatures and extended operation times structural changes including partial crystallinity may appear in these amorphous metallic systems. A systematic evaluation of the impact of partial crystallinity/devitrification on the diffusion and solubility behavior in multi-component Metallic Glass materials would provide great insight into the potential of these materials for hydrogen applications. This study will report on the development of time and temperature crystallization mapping and their use for interpretation of 'in-situ' hydrogen permeation at elevated temperatures.

  2. STRUCTURAL INTERACTIONS OF HYDROGEN WITH BULK AMORPHOUS MICROSTRUCTURES IN METALLIC SYSTEMS UNDERSTANDING THE ROLE OF PARTIAL CRYSTALLINITY ON PERMEATION AND EMBRITTLEMENT

    Brinkman, Kyle; Fox, Elise; Korinko, Paul; Adams, Thad

    2010-05-10

    The development of metallic glasses in bulk form has led to a resurgence of interest into the utilization of these materials for a variety of applications. A potentially exciting application for these bulk metallic glass (BMG) materials is their use as composite membranes to replace high cost Pd/Pd-alloy membranes for enhanced gas separation processes. One of the major drawbacks to the industrial use of Pd/Pd-alloy membranes is that during cycling above and below a critical temperature an irreversible change takes place in the palladium lattice structure which can result in significant damage to the membrane. Furthermore, the cost associated with Pd-based membranes is a potential detractor for their continued use and BMG alloys offer a potentially attractive alternative. Several BMG alloys have been shown to possess high permeation rates, comparable to those measured for pure Pd metal. In addition, high strength and toughness when either in-situ or ex-situ second phase dispersoids are present. Both of these properties, high permeation and high strength/toughness, potentially make these materials attractive for gas separation membranes that could resist hydrogen 'embrittlement'. However, a fundamental understanding of the relationship between partially crystalline 'structure'/devitrification and permeation/embrittlement in these BMG materials is required in order to determine the operating window for separation membranes and provide additional input to the material synthesis community for improved alloy design. This project aims to fill the knowledge gap regarding the impact of crystallization on the permeation properties of metallic glass materials. The objectives of this study are to (i) determine the crystallization behavior in different gas environments of Fe and Zr based commercially available bulk metallic glass and (ii) quantify the effects of partial crystallinity on the hydrogen permeation properties of these metallic glass membranes.

  3. Hydrogen permeation properties of plasma-sprayed tungsten

    Anderl, R.A.; Pawelko, R.J.; Hankins, M.R.; Longhurst, G.R.; Neiser, R.A.

    1994-01-01

    Tungsten has been proposed as a plasma-facing component material for advanced fusion facilities. This paper reports on laboratory-scale studies that were done to assess the hydrogen permeation properties of plasma-sprayed tungsten for such applications. The work entailed deuterium permeation measurements for plasma-sprayed (PS) tungsten coatings, sputter-deposited (SP) tungsten coatings, and steel substrate material using a mass-analyzed, 3 keV D + 3 ion beam with fluxes of similar 6.5x10 19 D/m 2 s. Extensive characterization analyses for the plasma-sprayed tungsten coatings were made using Auger spectrometry and scanning electron microscopy (SEM). Observed permeation rates through composite PS-tungsten/steel specimens were several orders of magnitude below the permeation levels observed for SP-tungsten/steel composite specimens and pure steel specimens. Characterization analyses indicated that the plasma-sprayed tungsten coating had a nonhomogeneous microstructure that consisted of splats with columnar solidification, partially-melted particles with grain boundaries, and void regions. Reduced permeation levels can be attributed to the complex microstructure and a substantial surface-connected porosity. ((orig.))

  4. Hydrogen permeation properties of plasma-sprayed tungsten

    Anderl, R.A. (Idaho National Engineering Lab., EG and G Idaho Inc., Idaho Falls, ID (United States)); Pawelko, R.J. (Idaho National Engineering Lab., EG and G Idaho Inc., Idaho Falls, ID (United States)); Hankins, M.R. (Idaho National Engineering Lab., EG and G Idaho Inc., Idaho Falls, ID (United States)); Longhurst, G.R. (Idaho National Engineering Lab., EG and G Idaho Inc., Idaho Falls, ID (United States)); Neiser, R.A. (Sandia National Laboratories, Albuquerque, NM 87185 (United States))

    1994-09-01

    Tungsten has been proposed as a plasma-facing component material for advanced fusion facilities. This paper reports on laboratory-scale studies that were done to assess the hydrogen permeation properties of plasma-sprayed tungsten for such applications. The work entailed deuterium permeation measurements for plasma-sprayed (PS) tungsten coatings, sputter-deposited (SP) tungsten coatings, and steel substrate material using a mass-analyzed, 3 keV D[sup +][sub 3] ion beam with fluxes of similar 6.5x10[sup 19] D/m[sup 2] s. Extensive characterization analyses for the plasma-sprayed tungsten coatings were made using Auger spectrometry and scanning electron microscopy (SEM). Observed permeation rates through composite PS-tungsten/steel specimens were several orders of magnitude below the permeation levels observed for SP-tungsten/steel composite specimens and pure steel specimens. Characterization analyses indicated that the plasma-sprayed tungsten coating had a nonhomogeneous microstructure that consisted of splats with columnar solidification, partially-melted particles with grain boundaries, and void regions. Reduced permeation levels can be attributed to the complex microstructure and a substantial surface-connected porosity. ((orig.))

  5. Hydrogen permeation properties of plasma-sprayed tungsten*1

    Anderl, R. A.; Pawelko, R. J.; Hankins, M. R.; Longhurst, G. R.; Neiser, R. A.

    1994-09-01

    Tungsten has been proposed as a plasma-facing component material for advanced fusion facilities. This paper reports on laboratory-scale studies that were done to assess the hydrogen permeation properties of plasma-sprayed tungsten for such applications. The work entailed deuterium permeation measurements for plasma-sprayed (PS) tungsten coatings, sputter-deposited (SP) tungsten coatings, and steel substrate material using a mass-analyzed, 3 keV D 3+ ion beam with fluxes of ˜6.5 × 10 19 D/m 2 s. Extensive characterization analyses for the plasma-sprayed tungsten coatings were made using Auger spectrometry and scanning electron microscopy (SEM). Observed permeation rates through composite PS-tungsten/steel specimens were several orders of magnitude below the permeation levels observed for SP-tungsten/steel composite specimens and pure steel specimens. Characterization analyses indicated that the plasma-sprayed tungsten coating had a nonhomogeneous microstructure that consisted of splats with columnar solidification, partially-melted particles with grain boundaries, and void regions. Reduced permeation levels can be attributed to the complex microstructure and a substantial surface-connected porosity.

  6. Permeation barrier properties of thin oxide films on flexible polymer substrates

    Fahlteich, John; Fahland, Matthias; Schoenberger, Waldemar; Schiller, Nicolas

    2009-01-01

    Solar cells and organic electronic devices require an encapsulation to ensure sufficient lifetime. Key parameters of the encapsulation are permeation barrier, UV stability, temperature stability, optical transmission spectra and mechanical stability. The requirements depend very much on the specific application. Many work groups suggest multilayer stacks to meet the permeation requirements. In this paper the permeation barrier properties of the different constituents of such a multilayer stack are characterized. Different layer materials are compared regarding their water vapour and oxygen permeability as well as the influence of process parameters is examined. Finally temperature dependent permeation measurements are used to characterize the permeation mechanisms in the different constituents of the multilayer barrier

  7. Aqueous pathways dominate permeation of solutes across Pisum sativum seed coats and mediate solute transport via diffusion and bulk flow of water.

    Niemann, Sylvia; Burghardt, Markus; Popp, Christian; Riederer, Markus

    2013-05-01

    The permeability of seed coats to solutes either of biological or anthropogenic origin plays a major role in germination, seedling growth and seed treatment by pesticides. An experimental set-up was designed for investigating the mechanisms of seed coat permeation, which allows steady-state experiments with isolated seed coats of Pisum sativum. Permeances were measured for a set of organic model compounds with different physicochemical properties and sizes. The results show that narrow aqueous pathways dominate the diffusion of solutes across pea seed coats, as indicated by a correlation of permeances with the molecular sizes of the compounds instead of their lipophilicity. Further indicators for an aqueous pathway are small size selectivity and a small effect of temperature on permeation. The application of an osmotic water potential gradient across isolated seed coats leads to an increase in solute transfer, indicating that the aqueous pathways form a water-filled continuum across the seed coat allowing the bulk flow of water. Thus, the uptake of organic solutes across pea testae has two components: (1) by diffusion and (2) by bulk water inflow, which, however, is relevant only during imbibition. © 2012 Blackwell Publishing Ltd.

  8. Influence of bulk and surface phenomena on the hydrogen permeation through metals

    Waelbroeck, F.; Wienhold, P.; Winter, J.; Rota, E.; Bauno, T.

    1984-12-01

    We discuss the permeation of hydrogen through metals and alloys such as iron, nickel, steels and Inconel wherein H dissolves endothermically from an H 2 gas. We assume first that trapping centers, surface contamination layers, the saturation of the H surface coverage and the implantation profile - when energetic ions drive the permeation - can be neglected, that a quasi-equilibrium exists between the H atom concentration ν in the adsorbed layer and c in the near surface layers and that the H solubility and diffusivity are homogeneous in the membrane. We evaluate thereafter separately the influence of these various effects and identify the parameter domains where appreciable corrections result. The permeation phenomenon is complex even when these simplifications are made: the penetration rate is proportional to the flux of thermal molecules, atoms or energetic ions - depending upon the case - which strike the surface; the diffusion in the metal is proportional to the gradient of c; the release rate depends on c 2 ; the time-dependent diffusion equation includes a double spatial derivative of c. Permeation can only be fully described when computer codes such as PERI is used. Simple analytical relations are however obtained in several limiting cases. They are the object of this report. Some of them had already been derived by other authors but they were not shown to be part of a single, self consistent permeation model. A comparison of predicted and experimental results shows that the simplified model describes surprisingly accurately the hydrogen exchange between gas and metal solutions. (orig./GSCH)

  9. GAS PERMEATION PROPERTIES OF POLY(LACTIC ACID). (R826733)

    AbstractThe need for the development of polymeric materials based on renewable resources has led to the development of poly(lactic acid) (PLA) which is being produced from a feedstock of corn rather than petroleum. The present study examines the permeation of nitrogen...

  10. Characterization and bulk properties of oxides

    Sonder, E.; Connolly, T.F.

    1979-06-01

    The bulk properties of oxides are divided into two classes, intrinsic properties which depend solely on the identity of the material, and extrinsic ones, which differ for different samples of the same compound. Sources of tabulated numerical values of intrinsic properties are given and modern developments in information storage and retrieval are discussed. Extrinsic properties are shown to depend on defects and trace impurities in the samples. Techniques of trace impurity analysis are discussed and realistic limits of detection and accuracies are given for routine analyses

  11. Ionic Selectivity and Permeation Properties of Human PIEZO1 Channels.

    Radhakrishnan Gnanasambandam

    Full Text Available Members of the eukaryotic PIEZO family (the human orthologs are noted hPIEZO1 and hPIEZO2 form cation-selective mechanically-gated channels. We characterized the selectivity of human PIEZO1 (hPIEZO1 for alkali ions: K+, Na+, Cs+ and Li+; organic cations: TMA and TEA, and divalents: Ba2+, Ca2+, Mg2+ and Mn2+. All monovalent ions permeated the channel. At a membrane potential of -100 mV, Cs+, Na+ and K+ had chord conductances in the range of 35-55 pS with the exception of Li+, which had a significantly lower conductance of ~ 23 pS. The divalents decreased the single-channel permeability of K+, presumably because the divalents permeated slowly and occupied the open channel for a significant fraction of the time. In cell-attached mode, 90 mM extracellular divalents had a conductance for inward currents carried by the divalents of: 25 pS for Ba2+ and 15 pS for Ca2+ at -80 mV and 10 pS for Mg2+ at -50 mV. The organic cations, TMA and TEA, permeated slowly and attenuated K+ currents much like the divalents. As expected, the channel K+ conductance increased with K+ concentration saturating at ~ 45 pS and the KD of K+ for the channel was 32 mM. Pure divalent ion currents were of lower amplitude than those with alkali ions and the channel opening rate was lower in the presence of divalents than in the presence of monovalents. Exposing cells to the actin disrupting reagent cytochalasin D increased the frequency of openings in cell-attached patches probably by reducing mechanoprotection.

  12. Competition of bulk trapping and surface erosion in the kinetics of tritium inventory and permeation in plasma protection metals

    Federici, G.; Holland, D.F.; Esser, B.

    1996-01-01

    A simplified transient model is presented to describe the migration of implanted tritium in the presence of trap sites across the bulk of metallic substrates whose thickness is decreasing with time due to erosion. The subject is relevant for quantifying the tritium inventory in - and permeation through -plasma facing armours in the next generation of D-T fuelled tokamak devices (i.e., the International Thermonuclear Experimental Reactor). This paper describes the equations of the physical model and the main assumptions used to simplify the complex analysis, and surveys the influence of several parameters such as the implantation flux, the erosion rate, the armour temperature, the armour thickness, the density and trapping energy of neutron-induced traps, etc., which are all expected to play a key role in the phenomena investigated. The examples presented to show the applicability of the model include the results of a study performed for beryllium armours exposed to heat and particle loads similar to those expected on the ITER divertor plasma facing components and comparison is made with cases where erosion does not play any role. (orig.)

  13. Combined use of bile acids and aminoacids to improve permeation properties of acyclovir.

    Cirri, M; Maestrelli, F; Mennini, N; Mura, P

    2015-07-25

    The aim of this work was to develop a topical formulation with improved permeation properties of acyclovir. Ursodeoxycholic (UDC) and dehydrocholic (DHC) acids were tested as potential enhancers, alone or in combination with different aminoacids. Equimolar binary and ternary systems of acyclovir with cholic acids and basic, hydrophilic or hydrophobic aminoacids were prepared by co-grinding in a high vibrational micromill. Differential scanning calorimetry (DSC) was used to characterize the solid state of these systems, while their permeation properties were evaluated in vitro through a lipophilic artificial membrane. UDC was more than 2 times more effective than DHC in improving drug AUC and permeation rate. As for the ternary systems drug-UDC-aminoacid, only the combined use of l-lysine with UDC acid produced an evident synergistic effect in enhancing drug permeation properties, enabling an almost 3 and 8 times AUC increase compared to the binary UDC system or the pure drug, respectively. The best systems were selected for the development of topical cream formulations, adequately characterized and tested for in vitro drug permeation properties and stability on storage. The better performance revealed by acyclovir-UDC-l-lysine was mainly attributed to the formation of a more permeable activated system induced by the multicomponent co-grinding process. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Tritium permeation evaluation through vertical target of divertor based on recent tritium transport properties

    Nakamura, Hirofumi; Nishi, Masataka

    2003-11-01

    Re-evaluation of tritium permeation through vertical target of divertor under the ITER operation condition was carried out using tritium properties in the candidate materials such as the diffusion coefficient and the trapping factors in tungsten for armor, and the surface recombination coefficient on copper for the heat sink obtained by authours' recent investigation (authors' data), which simulated the plasma-facing conditions of ITER. Evaluation with the data set of previous evaluation was also carried out for comparison (previous data). The permeation analysis was carried out individually by classifying into the armor region (Carbon Fiber Composites and tungsten) and the slit region without armor (3% of armor surface area) assuming the incident flux and temperature for each region. As the results of the permeation analysis, estimated permeation amount with the authors' data was one order less than that with the previous data at the end of lifetime of the divertor due to authors' small diffusion coefficient of tritium in tungsten. It also indicated the possibility that permeation through the slit region of the armor tiles could dominate total permeation through the vertical target, since tritium permeation amount through tungsten armor with the authors' data was estimated to be reduced drastically smaller than that with the previous evaluation data. The result of a little tritium permeation amount through the vertical target with the authors' data ensured the conservatism of the current evaluation of tritium concentration in the primary cooling water in ITER divertor, as it indicated the possibility of direct drainage of the divertor primary cooling water. (author)

  15. Calculated Bulk Properties of the Actinide Metals

    Skriver, Hans Lomholt; Andersen, O. K.; Johansson, B.

    1978-01-01

    Self-consistent relativistic calculations of the electronic properties for seven actinides (Ac-Am) have been performed using the linear muffin-tin orbitals method within the atomic-sphere approximation. Exchange and correlation were included in the local spin-density scheme. The theory explains...... the variation of the atomic volume and the bulk modulus through the 5f series in terms of an increasing 5f binding up to plutonium followed by a sudden localisation (through complete spin polarisation) in americium...

  16. Elastic properties of superconducting bulk metallic glasses

    Hempel, Marius

    2015-01-01

    Within the framework of this thesis the elastic properties of a superconducting bulk metallic glass between 10 mK and 300 K were first investigated. In order to measure the entire temperature range, in particular the low temperature part, new experimental techniques were developed. Using an inductive readout scheme for a double paddle oscillator it was possible to determine the internal friction and the relative change of sound velocity of bulk metallic glasses with high precision. This allowed for a detailed comparison of the data with different models. The analysis focuses on the low temperature regime where the properties of glassy materials are governed by atomic tunneling systems as described by the tunneling model. The influence of conduction electrons in the normal conducting state and quasiparticles in the superconducting state of the glass were accounted for in the theoretical description, resulting in a good agreement over a large temperature range between measured data and prediction of the tunneling model. This allowed for a direct determination of the coupling constant between electrons and tunneling systems. In the vicinity of the transition temperature Tc the data can only be described if a modified distribution function of the tunneling parameters is applied.

  17. Solid state properties from bulk to nano

    Dresselhaus, Mildred; Cronin, Stephen; Gomes Souza Filho, Antonio

    2018-01-01

    This book fills a gap between many of the basic solid state physics and materials science books that are currently available. It is written for a mixed audience of electrical engineering and applied physics students who have some knowledge of elementary undergraduate quantum mechanics and statistical mechanics. This book, based on a successful course taught at MIT, is divided pedagogically into three parts: (I) Electronic Structure, (II) Transport Properties, and (III) Optical Properties. Each topic is explained in the context of bulk materials and then extended to low-dimensional materials where applicable. Problem sets review the content of each chapter to help students to understand the material described in each of the chapters more deeply and to prepare them to master the next chapters.

  18. The Kinetics and the Permeation Properties of Piezo Channels.

    Gnanasambandam, R; Gottlieb, P A; Sachs, F

    2017-01-01

    Piezo channels are eukaryotic, cation-selective mechanosensitive channels (MSCs), which show rapid activation and voltage-dependent inactivation. The kinetics of these channels are largely consistent across multiple cell types and different stimulation paradigms with some minor variability. No accessory subunits that associate with Piezo channels have been reported. They are homotrimers and each ∼300kD monomer has an N-terminal propeller blade-like mechanosensing module, which can confer mechanosensing capabilities on ASIC-1 (the trimeric non-MSC, acid-sensing ion channel-1) and a C-terminal pore module, which influences conductance, selectivity, and channel inactivation. Repeated stimulation can cause domain fracture and diffusion of these channels leading to synchronous loss of inactivation. The reconstituted channels spontaneously open only in asymmetric bilayers but lack inactivation. Mutations that cause hereditary xerocytosis alter PIEZO1 kinetics. The kinetics of the wild-type PIEZO1 and alterations thereof in mutants (M2225R, R2456K, and DhPIEZO1) are summarized in the form of a quantitative model and hosted online. The pore is permeable to alkali ions although Li + permeates poorly. Divalent cations, notably Ca 2+ , traverse the channel and inhibit the flux of monovalents. The large monovalent organic cations such as tetramethyl ammonium and tetraethyl ammonium can traverse the channel, but slowly, suggesting a pore diameter of ∼8Å, and the estimated in-plane area change upon opening is around 6-20nm 2 . Ruthenium red can enter the channel only from the extracellular side and seems to bind in a pocket close to residue 2496. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Gas-permeation properties of poly(ethylene oxide) poly(butylene terephthalate block copolymers

    Metz, S.J.; Mulder, M.H.V.; Wessling, Matthias

    2004-01-01

    This paper reports the gas-permeation properties of poly(ethylene oxide) (PEO) poly(butylene terephthalate) (PBT) segmented multiblock copolymers. These block copolymers allow a precise structural modification by the amount of PBT and the PEO segment length, enabling a systematic study of the

  20. CO2 permeation properties of poly(ethylene oxide)-based segmented block copolymers

    Husken, D.; Visser, Tymen; Wessling, Matthias; Gaymans, R.J.

    2010-01-01

    This paper discusses the gas permeation properties of poly(ethylene oxide) (PEO)-based segmented block copolymers containing monodisperse amide segments. These monodisperse segments give rise to a well phase-separated morphology, comprising a continuous PEO phase with dispersed crystallised amide

  1. Permeation Behavior and Physical Properties of Natural Rubber Nanocomposites

    Zukas, Walter; Sennett, Michael; Welsh, Elizabeth; Rodriguez, Axel; Ziegler, David; Touchet, Paul

    2004-01-01

    .... A study was carried out to examine the effects of varying nanoparticle morphology and composition on the mechanical and barrier properties of polymer nanocomposites made with natural rubber (NR...

  2. Tritium permeation evaluation through vertical target of divertor based on recent tritium transport properties

    中村 博文; 西 正孝

    2003-01-01

    Re-evaluation of tritium permeation through vertical target of divertor under the ITER operation condition was carried out using tritium transport properties in the candidate materials such as the diffusion coefficient and the trapping factors in tungsten for armor, and the surface recombination coefficient on copper for the heat sink obtained by authors' recent investigation (authors' data), which simulated the plasma-facing conditions of ITER. Evaluation with the data set of previous evalua...

  3. Effect of Bulk and Interfacial Rheological Properties on Bubble Dissolution

    Kloek, W.; Vliet, van T.; Meinders, M.

    2001-01-01

    This paper describes theoretical calculations of the combined effect of bulk and interracial rheological properties on dissolution behavior of a bubble in an infinite medium at saturated conditions. Either bulk or interracial elasticity can stop the bubble dissolution process, and stability criteria

  4. Pseudopotentials for calculating the bulk and surface properties of solids

    Cohen, M.L.

    1983-01-01

    A survey is presented describing research in condensed matter physics using pseudopotentials to calculate electronic, structural, and vibrational properties of solids. Semiconductors are emphasized, and both bulk and surface calculations are discussed. (author) [pt

  5. Austenitic stainless steel bulk property considerations for fusion reactors

    Mattas, R.F.

    1979-04-01

    The bulk properties of annealed 304, 316, and 20% cold-worked 316 stainless steels are evaluated for the temperature and radiation conditions expected in a near-term fusion reactor. Of interest are the thermophysical properties, void swelling produced by neutron radiaion, and the tensile, creep, and fatigue properties before and after irradiation

  6. Thermodynamic properties of bulk and confined water

    Mallamace, Francesco, E-mail: francesco.mallamace@unime.it [Dipartimento di Fisica e Scienza della Terra Università di Messina and CNISM, I-98168 Messina (Italy); Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Center for Polymer Studies and Department of Physics, Boston University, Boston, Massachusetts 02215 (United States); Corsaro, Carmelo [Dipartimento di Fisica e Scienza della Terra Università di Messina and CNISM, I-98168 Messina (Italy); Mallamace, Domenico [Dipartimento di Scienze dell' Ambiente, della Sicurezza, del Territorio, degli Alimenti e della Salute, Università di Messina, I-98166 Messina (Italy); Vasi, Sebastiano; Vasi, Cirino [IPCF-CNR, I-98166 Messina (Italy); Stanley, H. Eugene [Center for Polymer Studies and Department of Physics, Boston University, Boston, Massachusetts 02215 (United States)

    2014-11-14

    The thermodynamic response functions of water display anomalous behaviors. We study these anomalous behaviors in bulk and confined water. We use nuclear magnetic resonance (NMR) to examine the configurational specific heat and the transport parameters in both the thermal stable and the metastable supercooled phases. The data we obtain suggest that there is a behavior common to both phases: that the dynamics of water exhibit two singular temperatures belonging to the supercooled and the stable phase, respectively. One is the dynamic fragile-to-strong crossover temperature (T{sub L} ≃ 225 K). The second, T{sup *} ∼ 315 ± 5 K, is a special locus of the isothermal compressibility K{sub T}(T, P) and the thermal expansion coefficient α{sub P}(T, P) in the P–T plane. In the case of water confined inside a protein, we observe that these two temperatures mark, respectively, the onset of protein flexibility from its low temperature glass state (T{sub L}) and the onset of the unfolding process (T{sup *})

  7. Soft magnetic properties of bulk amorphous Co-based samples

    Fuezer, J.; Bednarcik, J.; Kollar, P.

    2006-01-01

    Ball milling of melt-spun ribbons and subsequent compaction of the resulting powders in the supercooled liquid region were used to prepare disc shaped bulk amorphous Co-based samples. The several bulk samples have been prepared by hot compaction with subsequent heat treatment (500 deg C - 575 deg C). The influence of the consolidation temperature and follow-up heat treatment on the magnetic properties of bulk samples was investigated. The final heat treatment leads to decrease of the coercivity to the value between the 7.5 to 9 A/m (Authors)

  8. Properties of Bulk Sintered Silver As a Function of Porosity

    Wereszczak, Andrew A [ORNL; Vuono, Daniel J [ORNL; Wang, Hsin [ORNL; Ferber, Mattison K [ORNL; Liang, Zhenxian [ORNL

    2012-06-01

    This report summarizes a study where various properties of bulk-sintered silver were investigated over a range of porosity. This work was conducted within the National Transportation Research Center's Power Device Packaging project that is part of the DOE Vehicle Technologies Advanced Power Electronics and Electric Motors Program. Sintered silver, as an interconnect material in power electronics, inherently has porosity in its produced structure because of the way it is made. Therefore, interest existed in this study to examine if that porosity affected electrical properties, thermal properties, and mechanical properties because any dependencies could affect the intended function (e.g., thermal transfer, mechanical stress relief, etc.) or reliability of that interconnect layer and alter how its performance is modeled. Disks of bulk-sintered silver were fabricated using different starting silver pastes and different sintering conditions to promote different amounts of porosity. Test coupons were harvested out of the disks to measure electrical resistivity and electrical conductivity, thermal conductivity, coefficient of thermal expansion, elastic modulus, Poisson's ratio, and yield stress. The authors fully recognize that the microstructure of processed bulk silver coupons may indeed not be identical to the microstructure produced in thin (20-50 microns) layers of sintered silver. However, measuring these same properties with such a thin actual structure is very difficult, requires very specialized specimen preparation and unique testing instrumentation, is expensive, and has experimental shortfalls of its own, so the authors concluded that the herein measured responses using processed bulk sintered silver coupons would be sufficient to determine acceptable values of those properties. Almost all the investigated properties of bulk sintered silver changed with porosity content within a range of 3-38% porosity. Electrical resistivity, electrical conductivity

  9. Effect of multiple film on the tritium permeation property in 316L stainless steel

    Yao Zhenyu; Hao Jiakun; Zhou Changshan; Shan Changqi

    2000-01-01

    The films of TiN + TiC + TiN and TiN + TiC + SiO 2 were deposited on the surface of 316L stainless steel by physical vapor deposition technology. The characteristics of films are tested by SEM technology, it shows that the films are compact, thermal shock-resistant, oxidation-resistant and have good compatibility with bulk. the SIMS and IR analysis results show that the tritium permeation barrier is formed when TiC and SiO 2 films are annealed in hydrogen above 300 degree C. The tritium permeability in 316L with film is measured at various temperature, the results show that the tritium permeability in 316L with TiN + TiC + SiO 2 film is 4-6 orders of magnitude lower, and that in 316L with TiN + TiC + TiN film is 4-5 orders of magnitude lower than that in 316L with Pd film at about 200-600 degree C. These films may be used as the surface coating of the first wall, tritium blanket and heat exchanger in fusion reactor

  10. Organic bulk heterojunction photovoltaic structures: design, morphology and properties

    Bulavko, G V; Ishchenko, A A

    2014-01-01

    Main approaches to the design of organic bulk heterojunction photovoltaic structures are generalized and systematized. Novel photovoltaic materials based on fullerenes, organic dyes and related compounds, graphene, conjugated polymers and dendrimers are considered. The emphasis is placed on correlations between the chemical structure and properties of materials. The effect of morphology of the photoactive layer on the photovoltaic properties of devices is analyzed. Main methods of optimization of the photovoltaic properties are outlined. The bibliography includes 338 references

  11. Mass production of bulk artificial nacre with excellent mechanical properties.

    Gao, Huai-Ling; Chen, Si-Ming; Mao, Li-Bo; Song, Zhao-Qiang; Yao, Hong-Bin; Cölfen, Helmut; Luo, Xi-Sheng; Zhang, Fu; Pan, Zhao; Meng, Yu-Feng; Ni, Yong; Yu, Shu-Hong

    2017-08-18

    Various methods have been exploited to replicate nacre features into artificial structural materials with impressive structural and mechanical similarity. However, it is still very challenging to produce nacre-mimetics in three-dimensional bulk form, especially for further scale-up. Herein, we demonstrate that large-sized, three-dimensional bulk artificial nacre with comprehensive mimicry of the hierarchical structures and the toughening mechanisms of natural nacre can be facilely fabricated via a bottom-up assembly process based on laminating pre-fabricated two-dimensional nacre-mimetic films. By optimizing the hierarchical architecture from molecular level to macroscopic level, the mechanical performance of the artificial nacre is superior to that of natural nacre and many engineering materials. This bottom-up strategy has no size restriction or fundamental barrier for further scale-up, and can be easily extended to other material systems, opening an avenue for mass production of high-performance bulk nacre-mimetic structural materials in an efficient and cost-effective way for practical applications.Artificial materials that replicate the mechanical properties of nacre represent important structural materials, but are difficult to produce in bulk. Here, the authors exploit the bottom-up assembly of 2D nacre-mimetic films to fabricate 3D bulk artificial nacre with an optimized architecture and excellent mechanical properties.

  12. Effect of membrane property and operating conditions on phytochemical properties and permeate flux during clarification of pineapple juice

    Laorko, Aporn; Li, Zhenyu; Tongchitpakdee, Sasitorn; Chantachum, Suphitchaya; Youravong, Wirote

    2010-01-01

    The effects of membrane property on the permeate flux, membrane fouling and quality of clarified pineapple juice were studied. Both microfiltration (membrane pore size of 0.1 and 0.2 μm) and ultrafiltration (membrane molecular weight cut-off (MWCO) of 30 and 100 kDa) membranes were employed. Membrane filtration did not have significant effects on the pH, reducing sugar and acidity of clarified juice whereas the suspended solids and microorganism were completely removed. The 0.2 μm membrane gave the highest permeate flux, total vitamin C content, total phenolic content and antioxidant capacity as well as the highest value of irreversible fouling. Based on these results, the membrane with pore size of 0.2 μm was considered to be the most suitable membrane for the clarification of pineapple juice. The optimum operating conditions for the clarification pineapple juice by membrane filtration was a cross-flow velocity of 3.4 ms-1 and transmembrane pressure (TMP) of 0.7 bar. An average flux of about 37 lm-2 h-1 was obtained during the microfiltration of pineapple juice under the optimum conditions using batch concentration mode. © 2010 Elsevier Ltd. All rights reserved.

  13. Effect of membrane property and operating conditions on phytochemical properties and permeate flux during clarification of pineapple juice

    Laorko, Aporn

    2010-10-01

    The effects of membrane property on the permeate flux, membrane fouling and quality of clarified pineapple juice were studied. Both microfiltration (membrane pore size of 0.1 and 0.2 μm) and ultrafiltration (membrane molecular weight cut-off (MWCO) of 30 and 100 kDa) membranes were employed. Membrane filtration did not have significant effects on the pH, reducing sugar and acidity of clarified juice whereas the suspended solids and microorganism were completely removed. The 0.2 μm membrane gave the highest permeate flux, total vitamin C content, total phenolic content and antioxidant capacity as well as the highest value of irreversible fouling. Based on these results, the membrane with pore size of 0.2 μm was considered to be the most suitable membrane for the clarification of pineapple juice. The optimum operating conditions for the clarification pineapple juice by membrane filtration was a cross-flow velocity of 3.4 ms-1 and transmembrane pressure (TMP) of 0.7 bar. An average flux of about 37 lm-2 h-1 was obtained during the microfiltration of pineapple juice under the optimum conditions using batch concentration mode. © 2010 Elsevier Ltd. All rights reserved.

  14. Gas Permeation and Physical Aging Properties of Iptycene Diamine-Based Microporous Polyimides

    Alghunaimi, Fahd; Ghanem, Bader; Alaslai, Nasser Y.; Swaidan, Raja; Litwiller, Eric; Pinnau, Ingo

    2015-01-01

    The synthesis and gas permeation properties of two 6FDA-dianhydride-based polyimides prepared from 2,6-diaminotriptycene (6FDA-DAT1) and its extended iptycene analog (6FDA-DAT2) are reported. The additional benzene ring on the extended triptycene moiety in 6FDA–DAT2 increases the free volume over 6FDA-DAT1 and reduces the chain packing efficiency. The BET surface area based on nitrogen adsorption in 6FDA-DAT2 (450 m2g−1) is ~40% greater than that of 6FDA-DAT1 (320 m2g−1). 6FDA-DAT1 shows a CO2 permeability of 120 Barrer and CO2/CH4 selectivity of 38, whereas 6FDA-DAT2 exhibits a 75% increase in CO2 permeability to 210 Barrer coupled with a moderate decrease in selectivity (CO2/CH4=30). Interestingly, minimal physical aging was observed over 150 days for both polymers and attributed to the high internal free volume of the shape-persistent iptycene geometries. The aged polyimides maintained CO2/CH4 selectivities of 25-35 along with high CO2 permeabilities of 90-120 Barrer up to partial CO2 pressures of 10 bar of an aggressive 50:50 CO2:CH4 mixed-gas feed, suggesting potential application in membranes for natural gas sweetening.

  15. Gas Permeation and Physical Aging Properties of Iptycene Diamine-Based Microporous Polyimides

    Alghunaimi, Fahd

    2015-05-12

    The synthesis and gas permeation properties of two 6FDA-dianhydride-based polyimides prepared from 2,6-diaminotriptycene (6FDA-DAT1) and its extended iptycene analog (6FDA-DAT2) are reported. The additional benzene ring on the extended triptycene moiety in 6FDA–DAT2 increases the free volume over 6FDA-DAT1 and reduces the chain packing efficiency. The BET surface area based on nitrogen adsorption in 6FDA-DAT2 (450 m2g−1) is ~40% greater than that of 6FDA-DAT1 (320 m2g−1). 6FDA-DAT1 shows a CO2 permeability of 120 Barrer and CO2/CH4 selectivity of 38, whereas 6FDA-DAT2 exhibits a 75% increase in CO2 permeability to 210 Barrer coupled with a moderate decrease in selectivity (CO2/CH4=30). Interestingly, minimal physical aging was observed over 150 days for both polymers and attributed to the high internal free volume of the shape-persistent iptycene geometries. The aged polyimides maintained CO2/CH4 selectivities of 25-35 along with high CO2 permeabilities of 90-120 Barrer up to partial CO2 pressures of 10 bar of an aggressive 50:50 CO2:CH4 mixed-gas feed, suggesting potential application in membranes for natural gas sweetening.

  16. Pressure-dependent pure- and mixed-gas permeation properties of Nafion®

    Mukaddam, Mohsin Ahmed

    2016-04-20

    The permeation properties of Nafion® at 35 °C are presented for pure gases H2, N2, O2, CH4, CO2, C2H6 and C3H8, as a function of pressure between 2 and 20 atm. The effect of pressure on permeability and selectivity is analyzed to understand two observed phenomena: compression and plasticization. In pure-gas experiments, at increasing feed pressure, compression of the polymer matrix reduced the permeability of low-sorbing penetrants H2, N2, O2, and CH4. In contrast, permeabilities of more soluble penetrants CO2 and C2H6 increased by 18% and 46% respectively, as plasticization effects overcame compression effects. Permeability of C3H8 decreased slightly with increasing pressure up to 4.6 atm as a result of compression, then increased by 3-fold at 9 atm as a result of plasticization associated with high C3H8 solubility. Binary CO2/CH4 (50:50) mixed-gas experiments at total feed pressures up to 36 atm quantified the effect of CO2 plasticization on separation performance. At 10 atm CO2 partial pressure, CH4 permeability increased by 23% relative to its pure-gas value of 0.078 Barrer, while CO2 permeability decreased by 28%. Consequently, CO2/CH4 selectivity decreased to 19, i.e., 42% below its pure-gas value of 32.

  17. S-protected thiolated chitosan for oral delivery of hydrophilic macromolecules: evaluation of permeation enhancing and efflux pump inhibitory properties.

    Dünnhaupt, Sarah; Barthelmes, Jan; Rahmat, Deni; Leithner, Katharina; Thurner, Clemens C; Friedl, Heike; Bernkop-Schnürch, Andreas

    2012-05-07

    The objective of this study was the investigation of permeation enhancing and P-glycoprotein (P-gp) inhibition effects of a novel thiolated chitosan, the so-named S-protected thiolated chitosan. Mediated by a carbodiimide, increasing amounts of thioglycolic acid (TGA) were covalently bound to chitosan (CS) in the first step of modification. In the second step, these thiol groups of thiolated chitosan were protected by disulfide bond formation with the thiolated aromatic residue 6-mercaptonicotinamide (6-MNA). Mucoadhesive properties of all conjugates were evaluated in vitro on porcine intestinal mucosa based on tensile strength investigations. Permeation enhancing effects were evaluated ex vivo using rat intestinal mucosa and in vitro via Caco-2 cells using the hydrophilic macromolecule FD(4) as the model drug. Caco-2 cells were further used to show P-gp inhibition effects by using Rho-123 as P-gp substrate. Apparent permeability coefficients (P(app)) were calculated and compared to values obtained from each buffer control. Three different thiolated chitosans were generated in the first step of modification, which displayed increasing amounts of covalently attached free thiol groups on the polymer backbone. In the second modification step, more than 50% of these free thiol groups were covalently linked with 6-MNA. Within 3 h of permeation studies on excised rat intestine, P(app) values of all S-protected chitosans were at least 1.3-fold higher compared to those of corresponding thiomers and more than twice as high as that of unmodified chitosan. Additional permeation studies on Caco-2 cells confirmed these results. Because of the chemical modification and higher amount of reactive thiol groups, all S-protected thiolated chitosans exhibit at least 1.4-fold pronounced P-gp inhibition effects in contrast to their corresponding thiomers. These features approve S-protected thiolated chitosan as a promising excipient for various drug delivery systems providing improved

  18. Bulk viscous matter-dominated Universes: asymptotic properties

    Avelino, Arturo [Departamento de Física, Campus León, Universidad de Guanajuato, León, Guanajuato (Mexico); García-Salcedo, Ricardo [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada - Legaria del IPN, México D.F. (Mexico); Gonzalez, Tame [Departamento de Ingeniería Civil, División de Ingeniería, Universidad de Guanajuato, Guanajuato (Mexico); Nucamendi, Ulises [Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio C-3, Ciudad Universitaria, CP. 58040 Morelia, Michoacán (Mexico); Quiros, Israel, E-mail: avelino@fisica.ugto.mx, E-mail: rigarcias@ipn.mx, E-mail: tamegc72@gmail.com, E-mail: ulises@ifm.umich.mx, E-mail: iquiros6403@gmail.com [Departamento de Matemáticas, Centro Universitario de Ciencias Exactas e Ingenierías (CUCEI), Corregidora 500 S.R., Universidad de Guadalajara, 44420 Guadalajara, Jalisco (Mexico)

    2013-08-01

    By means of a combined use of the type Ia supernovae and H(z) data tests, together with the study of the asymptotic properties in the equivalent phase space — through the use of the dynamical systems tools — we demonstrate that the bulk viscous matter-dominated scenario is not a good model to explain the accepted cosmological paradigm, at least, under the parametrization of bulk viscosity considered in this paper. The main objection against such scenarios is the absence of conventional radiation and matter-dominated critical points in the phase space of the model. This entails that radiation and matter dominance are not generic solutions of the cosmological equations, so that these stages can be implemented only by means of unique and very specific initial conditions, i. e., of very unstable particular solutions. Such a behavior is in marked contradiction with the accepted cosmological paradigm which requires of an earlier stage dominated by relativistic species, followed by a period of conventional non-relativistic matter domination, during which the cosmic structure we see was formed. Also, we found that the bulk viscosity is positive just until very late times in the cosmic evolution, around z < 1. For earlier epochs it is negative, been in tension with the local second law of thermodynamics.

  19. Mechanical properties of Nd-Ba-Cu-O bulk superconductors

    Matsui, Motohide; Sakai, Naomichi; Murakami, Masato; Osamura, Kozo

    2003-01-01

    We investigated the effects of Nd422 and Ag particles on the mechanical properties in Nd-Ba-Cu-O bulk superconductors. Both Nd422 and Ag particles were effective in decreasing the amount of microcracks running along the c direction. In the case of Nd422, however, excessive Nd422 addition enhanced the crack propagation, resulting in the degradation of mechanical strength. In the case of Ag addition, the beneficial effect of its ductile mechanical property was not observed. This was due to a relatively large size of Ag particles and low interfacial strength between Ag and Nd123 matrix. It was remarkable that the Weibull coefficient of the sample with Ag 2 O addition exceeded 13, which is reliable enough for practical engineering applications

  20. Metastability and thermophysical properties of metallic bulk glass forming alloys

    Wunderlich, R.K.; Fecht, H.J.

    1998-01-01

    The absence of crystallization over a wide time/temperature window can be used to produce bulk metallic glass by relatively slow cooling of the melt. For a number of alloys, including several multicomponent Zr-based alloys, the relevant thermodynamic and thermomechanical properties of the metastable glassy and undercooled liquid states have been measured below and above the glass transition temperature. These measurements include specific heat, viscosity, volume, and elastic properties as a function of temperature. As a result, it becomes obvious that the maximum undercooling for these alloys is given by an isentropic condition before an enthalpic or isochoric instability is reached. Alternatively, these glasses can also be produced by mechanical alloying, thus replacing the thermal disorder by static disorder and resulting in the same thermodynamic glass state. During heating through the undercooled liquid, a nanoscale phase separation occurs for most glasses as a precursor of crystallization

  1. Permeation through graphene ripples

    Liang, Tao; He, Guangyu; Wu, Xu; Ren, Jindong; Guo, Hongxuan; Kong, Yuhan; Iwai, Hideo; Fujita, Daisuke; Gao, Hongjun; Guo, Haiming; Liu, Yingchun; Xu, Mingsheng

    2017-06-01

    Real graphene sheets show limited anti-permeation performance deviating from the ideally flat honeycomb carbon lattice that is impermeable to gases. Ripples in graphene are prevalent and they could significantly influence carrier transport. However, little attention has been paid to the role of ripples in the permeation properties of graphene. Here, we report that gases can permeate through graphene ripples at room temperature. The feasibility of gas permeation through graphene ripples is determined by detecting the initial oxidation sites of Cu surface covered with isolated graphene domain. Nudged elastic band (NEB) calculations demonstrate that the oxygen atom permeation occurs via the formation of C-O-C bond, in which process the energy barrier through the rippled graphene lattice is much smaller than that through a flat graphene lattice, rendering permeation through ripples more favorable. Combining with the recent advances in atoms intercalation between graphene and metal substrate for transfer-free and electrically insulated graphene, this discovery provides new perspectives regarding graphene’s limited anti-permeation performance and evokes for rational design of graphene-based encapsulation for barrier and selective gas separation applications through ripple engineering.

  2. Correlations between elastic moduli and properties in bulk metallic glasses

    Wang Weihua

    2006-01-01

    A survey of the elastic, mechanical, fragility, and thermodynamic properties of bulk metallic glasses (BMGs) and glass-forming liquids is presented. It is found that the elastic moduli of BMGs have correlations with the glass transition temperature, melting temperature, mechanical properties, and even liquid fragility. On the other hand, the elastic constants of available BMGs show a rough correlation with a weighted average of the elastic constants for the constituent elements. Although the theoretical and physical reasons for the correlations are to be clarified, these correlations could assist in understanding the long-standing issues of glass formation and the nature of glass and simulate the work of theorists. Based on the correlation, we show that the elastic moduli can assist in selecting alloying components for controlling the elastic properties and glass-forming ability of the BMGs and thus can guide BMG design. As case study, we report the formation of the families of rare-earth-based BMGs with controllable properties

  3. Iron phosphate glasses: Bulk properties and atomic scale structure

    Joseph, Kitheri; Stennett, Martin C.; Hyatt, Neil C.; Asuvathraman, R.; Dube, Charu L.; Gandy, Amy S.; Govindan Kutty, K. V.; Jolley, Kenny; Vasudeva Rao, P. R.; Smith, Roger

    2017-10-01

    Bulk properties such as glass transition temperature, density and thermal expansion of iron phosphate glass compositions, with replacement of Cs by Ba, are investigated as a surrogate for the transmutation of 137Cs to 137Ba, relevant to the immobilisation of Cs in glass. These studies are required to establish the appropriate incorporation rate of 137Cs in iron phosphate glass. Density and glass transition temperature increases with the addition of BaO indicating the shrinkage and reticulation of the iron phosphate glass network. The average thermal expansion coefficient reduces from 19.8 × 10-6 K-1 to 13.4 × 10-6 K-1, when 25 wt. % of Cs2O was replaced by 25 wt. % of BaO in caesium loaded iron phosphate glass. In addition to the above bulk properties, the role of Ba as a network modifier in the structure of iron phosphate glass is examined using various spectroscopic techniques. The FeII content and average coordination number of iron in the glass network was estimated using Mössbauer spectroscopy. The FeII content in the un-doped iron phosphate glass and barium doped iron phosphate glasses was 20, 21 and 22 ± 1% respectively and the average Fe coordination varied from 5.3 ± 0.2 to 5.7 ± 0.2 with increasing Ba content. The atomic scale structure was further probed by Fe K-edge X-ray absorption spectroscopy. The average coordination number provided by extended X-ray absorption fine structure spectroscopy and X-ray absorption near edge structure was in good agreement with that given by the Mössbauer data.

  4. Corneal permeation properties of a charged lipid nanoparticle carrier containing dexamethasone

    Ban, Junfeng; Zhang, Yan; Huang, Xin; Deng, Guanghan; Hou, Dongzhi; Chen, Yanzhong; Lu, Zhufen

    2017-01-01

    Drug delivery carriers can maintain effective therapeutic concentrations in the eye. To this end, we developed lipid nanoparticles (L/NPs) in which the surface was modified with positively charged chitosan, which engaged in hydrogen bonding with the phospholipid membrane. We evaluated in vitro corneal permeability and release characteristics, ocular irritation, and drug dynamics of modified and unmodified L/NPs in aqueous humor. The size of L/NPs was uniform and showed a narrow distribution. Corneal permeation was altered by the presence of chitosan and was dependent on particle size; the apparent permeability coefficient of dexamethasone increased by 2.7 and 1.8 times for chitosan-modified and unmodified L/NPs, respectively. In conclusion, a chitosan-modified system could be a promising method for increasing the ocular bioavailability of unmodified L/NPs by enhancing their retention time and permeation into the cornea. These findings provide a theoretical basis for the development of effective drug delivery systems in the treatment of ocular disease. PMID:28243093

  5. Effects of sterilization treatments on bulk and surface properties of nanocomposite biomaterials.

    Ahmed, Maqsood; Punshon, Geoffrey; Darbyshire, Arnold; Seifalian, Alexander M

    2013-10-01

    With the continuous and expanding use of implantable biomaterials in a clinical setting, this study aims to elucidate the influence of sterilization techniques on the material surface and bulk properties of two polyurethane nanocomposite biomaterials. Both solid samples and porous membranes of nondegradable polyhedral oligomeric silsesquioxane poly(carbonate-urea) urethane (POSS-PCU) and a biodegradable poly(caprolactone-urea) urethane (POSS-PCL) were examined. Sterilization techniques included conventional steam sterilization (autoclaving), gamma irradiation, and disinfection via incubating with ethanol (EtOH) for 10 min or 24 h. After treatment, the samples were examined using gel permeation chromatography (GPC), attenuated total reflectance Fourier transform infrared spectroscopy, and tensiometry. Cytotoxicity was evaluated through the culture of endothelial progenitor cells and the efficacy of sterilization method was determined by incubating each sample in tryptone soya broth and fluid thioglycollate medium for cultivation of microorganisms. Although EtOH did not affect the material properties in any form, the samples were found to be nonsterile with microbial growth detected on each of the samples. Gamma irradiation was not only effective in sterilizing both POSS-PCU and POSS-PCL but also led to minor material degradation and displayed a cytotoxic effect on the cultured cells. Autoclaving was found to be the optimal sterilization technique for both solid and porous membranes of the nondegradable POSS-PCU samples as it was successful in sterilizing the samples, displayed no cytotoxic side effects and did not degrade the material. However, the biodegradable POSS-PCL was not able to withstand the harsh environment during autoclaving, resulting in it losing all structural integrity. Copyright © 2013 Wiley Periodicals, Inc., a Wiley Company.

  6. Effects of surface coating process conditions on the water permeation and salt rejection properties of composite polyamide reverse osmosis membranes

    Louie, Jennifer Sarah

    2011-02-01

    The application of polymer surface coatings to improve the fouling resistance of reverse osmosis membranes tends to increase flow resistance across the membrane. This paper presents a systematic analysis on how membrane properties and performance are impacted by the coating process steps, and investigates how such effects could contribute to lower water flux. On one hand, simply pre-soaking dry aromatic polyamide composite membranes in aliphatic alcohols results in a significant increase in water flux, which is attributed to wetting of pores in the selective polyamide layer and to changes in the polymer structure. This flux increase was not readily reversible, based on a 300-h water permeation test. Conversely, drying a wetted membrane led to a decrease in water flux, which we hypothesize is caused by increased interchain hydrogen-bonding in the selective layer. This drop in water flux was not permanent; higher flux was observed if the same wetted/dried membrane was then re-soaked in ethanol prior to the water permeation experiment. An ethanol pre-soaking step also increased water flux of a PEBAX-coated membrane by nearly 70%. In contrast to the reduction in water flux caused by the specific treatment sequence of ethanol-swelling followed by drying, this same sequence actually increased gas transport. The eight- to ten-fold increase in Knudsen diffusion-based gas permeance after this pre-treatment was attributed to an increase in the number or size of membrane defects. © 2010 Elsevier B.V.

  7. Influence of Bulk PDMS Network Properties on Water Wettability

    Melillo, Matthew; Walker, Edwin; Klein, Zoe; Efimenko, Kirill; Genzer, Jan

    Poly(dimethylsiloxane) (PDMS) is one of the most common elastomers, with applications ranging from sealants and marine antifouling coatings to absorbents for water treatment. Fundamental understanding of how liquids spread on the surface of and absorb into PDMS networks is of critical importance for the design and use of another application - medical devices. We have systematically studied the effects of polymer molecular weight, loading of tetra-functional crosslinker, and end-group chemical functionality on the mechanical and surface properties of end-linked PDMS networks. Wettability was investigated through the sessile drop technique, wherein a DI water droplet was placed on the bulk network surface and droplet volume, shape, surface area, and contact angle were monitored as a function of time. Various silicone substrates ranging from incredibly soft and flexible materials (E' 50 kPa) to highly rigid networks (E' 5 MPa) were tested. The dynamic behavior of the droplet on the surfaces demonstrated equilibration times between the droplet and surface on the order of 5 minutes. Similar trends were observed for the commercial PDMS material, Sylgard-184. Our results have provided new evidence for the strong influence that substrate modulus and molecular network structure have on the wettability of PDMS elastomers. These findings will aid in the design and implementation of efficient, accurate, and safe PDMS-based medical devices and microfluidic materials that involve aqueous media.

  8. Thermal properties of superconducting bulk metallic glasses at ultralow temperatures

    Rothfuss, Daniel Simon

    2013-01-01

    This thesis describes the first investigation of thermal properties of superconducting bulk metallic glasses in the range between 6mK and 300K. Measuring the thermal conductivity provides the possibility to probe the fundamental interactions governing the heat flow in solids. At ultralow temperatures a novel contactless measuring technique was used, which is based on optical heating and paramagnetic temperature sensors that are read out by a SQUID magnetometer. Below the critical temperature T c the results can be described by resonant scattering of phonons by tunneling systems. Above T c the phonon contribution to the thermal conductivity can be described successfully within a model considering not only electrons and phonons but also localized modes as scattering centres. To expand the accessible temperature range for experiments an adiabatic nuclear demagnetization refrigerator was set up. For measuring the base temperature a novel noise thermometer was developed which enables continuous measuring of the temperature in this temperature range for the first time. Therefore the magnetic Johnson noise of a massive copper cylinder is simultaneously monitored by two SQUID magnetometers. A subsequent cross-correlation suppresses the amplifier noise by more than one order of magnitude. The thermometer was characterized between 42μK and 0.8K showing no deviation from the expected linear behaviour between the power spectral density of the thermal noise and the temperature.

  9. Bulk plasma properties in the pulsed glow discharge

    Jackson, Glen P.; King, Fred L.

    2003-01-01

    This work focuses on the spatial and temporal characteristics of a glow discharge plasma operated with power pulses of 5 ms in duration at 25% duty cycle. Interpretation of emission data provides insight into the nature of the plasma at each instant of a typical pulse cycle and at each position in space. Because the bulk plasma properties affect the distribution of excited energy levels of the sputtered atoms, an improved understanding of the plasma affords the ability to select conditions that enhance analytically important emission lines. Optical emission spectroscopy was used to determine the relative populations of excited states for atoms and ions during the initial breakdown, the steady state and the recombining periods of the discharge pulse cycle. The plasma is highly ionizing in nature at the time of breakdown--with lower excited states being overpopulated--before reaching the steady state, or plateau, period, also ionizing in nature. These behaviors arise from a loss of charged particles and photons to the surroundings that shifts the plasma away from Saha and Boltzmann balances during these periods. The post-pulse period typically displays recombining behavior, characterized by population inversion for selected species--except for regions close to the cathode, where electrons and ions are lost by diffusion and are not available for recombination. The sputtered analyte atom emissions closely mimic those of the plasma bath gas, except that their emissions persevere for longer in the recombining after-peak period than do the discharge gas species

  10. Changes in the physical properties of the dynamic layer and its correlation with permeate quality in a self-forming dynamic membrane bioreactor.

    Guan, Dao; Dai, Ji; Watanabe, Yoshimasa; Chen, Guanghao

    2018-09-01

    The self-forming dynamic membrane bioreactor (SFDMBR) is a biological wastewater treatment technology based on the conventional membrane bioreactor (MBR) with membrane material modification to a large pore size (30-100 μm). This modification requires a dynamic layer formed by activated sludge to provide effective filtration function for high-quality permeate production. The properties of the dynamic layer are therefore important for permeate quality in SFDMBRs. The interaction between the structure of the dynamic layer and the performance of SFDMBRs is little known but understandably complex. To elucidate the interaction, a lab-scale SFDMBR system coupled with a nylon woven mesh as the supporting material was operated. After development of a mature dynamic layer, excellent solid-liquid separation was achieved, as evidenced by a low permeate turbidity of less than 2 NTU. The permeate turbidity stayed below this level for nearly 80 days. In the fouling phase, the dynamic layer was compressed with an increase in the trans-membrane pressure and the quality of the permeate kept deteriorating until the turbidity exceeded 10 NTU. The investigation revealed that the majority of permeate particles were dissociated from the dynamic layer on the back surface of the supporting material, which is caused by the compression, breakdown, and dissociation of the dynamic layer. This phenomenon was observed directly in experiment instead of model prediction or conjecture for the first time. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Bulk microstructure and local elastic properties of carbon nanocomposites studied by impulse acoustic microscopy technique

    Levin, V.; Petronyuk, Yu.; Morokov, E.; Chernozatonskii, L.; Kuzhir, P.; Fierro, V.; Celzard, A.; Bellucci, S.; Bistarelli, S.; Mastrucci, M.; Tabacchioni, I.

    2016-05-01

    Bulk microstructure and elastic properties of epoxy-nanocarbon nanocomposites for diverse types and different content of carbon nanofiller has been studied by using impulse acoustic microscopy technique. It has been shown occurrence of various types of mesoscopic structure formed by nanoparticles inside the bulk of nanocomposite materials, including nanoparticle conglomerates and nanoparticle aerogel systems. In spite of the bulk microstructure, nanocarbon composites demonstrate elastic uniformity and negligible influence of nanofiller on elastic properties of carbon nanocomposite materials.

  12. Effect of coagulant bath on the gas permeation properties of cellulose acetate asymmetric membrane

    Mohamed, F.; Hasbullah, H.; Jami'an, W. N. R.; Salleh, W. N. H. W.; Ibrahim, N.; Ali, R. R.

    2016-06-01

    Membrane based gas separation process technology has been recognized as one of the most efficient and advanced unit operation for gas separation. One of the problems in membrane gas separation is membrane performance. This paper explores the application of cellulose acetate (CA) membrane for natural gas purification and separation by improving its permeability and selectivity. The main interest in this research is to study the effect of quench medium on the gas separation performance towards its physical characteristics and gas separation performance of CA membrane. Cellulose acetate polymer was dissolved in n- methyl-2-pyrrolidone solvent and casted onto a glass plate using a pneumatically controlled casting system with fixed shear rate and solvent evaporation times. The parameter varied was the non-solvent used as quench medium during membrane post treatment that were methanol and n-hexane. The different quench media as post treatment affected the O2 and N2 gas permeation and O2/N2 selectivity as well as the tensile strength of the flat sheet asymmetric membrane. Combination of methanol and n-hexane as quench media gave the best result than the other steps. This solvent exchange step influenced the morphology by producing thin skin layer and thus gives better gas separation performance than other steps

  13. High temperature superconductor bulk materials. Fundamentals - processing - properties control - application aspects

    Krabbes, G.; Fuchs, G.; Canders, W.R.; May, H.; Palka, R.

    2006-01-01

    This book presents all the features of bulk high temperature superconducting materials. Starting from physical and chemical fundamentals, the authors move on to portray methods and problems of materials processing, thoroughly working out the characteristic properties of bulk superconductors in contrast to long conductors and films. The authors provide a wide range of specific materials characteristics with respect to the latest developments and future applications guiding from fundamentals to practical engineering examples. This book contains the following chapters: 1. Fundamentals 2. Growth and melt processing of YBCO 3. Pinning-relevant defects in bulk YBCO 4. Properties of bulk YBCO 5. Trapped fields 6. Improved YBCO based bulk superconductors and functional elements 7. Alternative systems 8. Peak effect 9. Very high trapped fields in YBCO permanent magnets 10. Engineering aspects: Field distribution in bulk HTSC 11. Inherently stable superconducting magnetic bearings 12. Application of bulk HTSCs in electromagnetic energy converters 13. Applications in magnet technologies and power supplies

  14. Liquid and Gas Permeation Studies on the Structure and Properties of Polyamide Thin-Film Composite Membranes

    Duan, Jintang

    2014-11-01

    This research was undertaken to improve the understanding of structure-property-performance relationships in crosslinked polyamide (PA) thin-film composite (TFC) membranes as characterized by liquid and gas permeation studies. The ultrathin PA selective layer formed by interfacial polymerization between meta-phenylene diamine and trimesoyl chloride was confirmed to contain dense polymer matrix regions and defective regions in both dry and hydrated states. The first part of this research studied the effect of non-selective convection through defective regions on water flux and solute flux in pressure-assisted forward osmosis (PAFO). Through systematic comparison with cellulose triacetate (CTA) and PEBAX-coated PA-TFC membranes, the existence of defects in pristine, hydrated PA-TFC membranes was verified, and their effects were quantified by experimental and modeling methods. In the membrane orientation of selective layer facing the draw solution, water flux increases of up to 10-fold were observed to result from application of low hydraulic pressure (1.25 bar). Convective water flux through the defects was low (< 1% of total water flux for PA-TFC membranes) and of little consequence in practical FO or reverse osmosis (RO) applications. However, it effectively mitigated the concentration polarization in PAFO and therefore greatly increased the diffusive flux through the dense regions. The second part of this research characterized the structures of the PA material and the PA selective layer by gas adsorption and gas permeation measurements. Gas adsorption isotherms (N2 at 77K, CO2 at 273K) confirmed the microporous nature of PA in comparison with dense CTA and polysulfone materials. Gas permeation through the commercial PA-TFC membranes tested occurred primarily in the defective regions, resulting in Knudsen gas selectivity for various gas pairs. Applying a Nafion coating layer effectively plugged the defects and allowed gas permeation through the dense PA regions

  15. Atomistic simulations of bulk, surface and interfacial polymer properties

    Natarajan, Upendra

    In chapter I, quasi-static molecular mechanics based simulations are used to estimate the activation energy of phenoxy rings flips in the amorphous region of a semicrystalline polyimide. Intra and intermolecular contributions to the flip activation energy, the torsional cooperativity accompanying the flip, and the effect of the flip on the motion in the glassy bulk state, are looked at. Also, comparison of the weighted mean activation energy is made with experimental data from solid state NMR measurements; the simulated value being 17.5 kcal/mol., while the experimental value was observed to be 10.5 kcal/mol. Chapter II deals with construction of random copolymer thin films of styrene-butadiene (SB) and styrene-butadiene-acrylonitrile (SBA). The structure and properties of the free surfaces presented by these thin films are analysed by, the atom mass density profiles, backbone bond orientation function, and the spatial distribution of acrylonitrile groups and styrene rings. The surface energies of SB and SBA are calculated using an atomistic equation and are compared with experimental data in the literature. In chapter III, simulations of polymer-polymer interfaces between like and unlike polymers, specifically cis-polybutadiene (PBD) and atatic polypropylene (PP), are presented. The structure of an incompatible polymer-polymer interface, and the estimation of the thermodynamic work of adhesion and interfacial energy between different incompatible polymers, form the focus here. The work of adhesion is calculated using an atomistic equation and is further used in a macroscopic equation to estimate the interfacial energy. The interfacial energy is compared with typical values for other immiscible systems in the literature. The interfacial energy compared very well with interfacial energy values for a few other immiscible hydrocarbon pairs. In chapter IV, the study proceeds to look at the interactions between nonpolar and polar small molecules with SB and SBA thin

  16. Ab-initio investigations of the electronic properties of bulk wurtzite Beryllia and its derived nanofilms

    Goumri-Said, Souraya; Kanoun, Mohammed Benali

    2010-01-01

    In this Letter we investigate the electronic properties of the bulk and the nanofilm BeO in wurtzite structure. We performed a first-principles pseudo-potential method within the generalized gradient approximation. We will give more importance to the changes in band structure and density of states between the bulk structure and its derived nanofilms. The bonding characterization will be investigated via the analysis Mulliken population and charge density contours. It is found that the nanofilm retains the same properties as its bulk structure with slight changes in electronic properties and band structure which may offer some unusual transport properties.

  17. Ab-initio investigations of the electronic properties of bulk wurtzite Beryllia and its derived nanofilms

    Goumri-Said, Souraya

    2010-08-01

    In this Letter we investigate the electronic properties of the bulk and the nanofilm BeO in wurtzite structure. We performed a first-principles pseudo-potential method within the generalized gradient approximation. We will give more importance to the changes in band structure and density of states between the bulk structure and its derived nanofilms. The bonding characterization will be investigated via the analysis Mulliken population and charge density contours. It is found that the nanofilm retains the same properties as its bulk structure with slight changes in electronic properties and band structure which may offer some unusual transport properties. © 2010 Elsevier B.V. All rights reserved.

  18. Liquid and Gas Permeation Studies on the Structure and Properties of Polyamide Thin-Film Composite Membranes

    Duan, Jintang

    2014-01-01

    layer by gas adsorption and gas permeation measurements. Gas adsorption isotherms (N2 at 77K, CO2 at 273K) confirmed the microporous nature of PA in comparison with dense CTA and polysulfone materials. Gas permeation through the commercial PA

  19. Modeling benzene permeation through drinking water high density polyethylene (HDPE) pipes.

    Mao, Feng; Ong, Say Kee; Gaunt, James A

    2015-09-01

    Organic compounds such as benzene, toluene, ethyl benzene and o-, m-, and p-xylene from contaminated soil and groundwater may permeate through thermoplastic pipes which are used for the conveyance of drinking water in water distribution systems. In this study, permeation parameters of benzene in 25 mm (1 inch) standard inside dimension ratio (SIDR) 9 high density polyethylene (HDPE) pipes were estimated by fitting the measured data to a permeation model based on a combination of equilibrium partitioning and Fick's diffusion. For bulk concentrations between 6.0 and 67.5 mg/L in soil pore water, the concentration-dependent diffusion coefficients of benzene were found to range from 2.0×10(-9) to 2.8×10(-9) cm2/s while the solubility coefficient was determined to be 23.7. The simulated permeation curves of benzene for SIDR 9 and SIDR 7 series of HDPE pipes indicated that small diameter pipes were more vulnerable to permeation of benzene than large diameter pipes, and the breakthrough of benzene into the HDPE pipe was retarded and the corresponding permeation flux decreased with an increase of the pipe thickness. HDPE pipes exposed to an instantaneous plume exhibited distinguishable permeation characteristics from those exposed to a continuous source with a constant input. The properties of aquifer such as dispersion coefficients (DL) also influenced the permeation behavior of benzene through HDPE pipes.

  20. Tritium permeation characterization of Al{sub 2}O{sub 3}/FeAl coatings as tritium permeation barriers on 321 type stainless steel containers

    Yang, Feilong; Xiang, Xin; Lu, Guangda; Zhang, Guikai, E-mail: zhangguikai@caep.cn; Tang, Tao; Shi, Yan; Wang, Xiaolin

    2016-09-15

    Accurate tritium transport properties of prospective tritium permeation barriers (TPBs) are essential to tritium systems in fusion reactors. By passing a temperature and rate-controlled sweeping gas over specimen surfaces to carry the permeated tritium to an ion chamber, the gas-driven permeation of tritium has been performed on 321 type stainless steel containers with Al{sub 2}O{sub 3}/FeAl barriers, to determine the T-permeation resistant performance and mechanism of the barrier. The tritium permeability of the Al{sub 2}O{sub 3}/FeAl coated container was reduced by 3 orders of magnitude at 500–700 °C by contrast with that of the bare one, which meets the requirement of the tritium permeation reduction factor (PRF) of TPBs for tritium operating components in the CN-HCCB TBM. The Al{sub 2}O{sub 3}/FeAl barrier resists the tritium permeation by the diffusion in the bulk substrate at a limited number of defect sites with an effective area and thickness, suggesting that the TPB quality is a very important factor for efficient T-permeation resistance. - Highlights: • T-permeation has been measured on bare and coated type 321 SS containers. • Al{sub 2}O{sub 3}/FeAl coating give a reduction of T-permeability of 3 orders of magnitude. • Mechanism of Al{sub 2}O{sub 3}/FeAl barrier resisting T-permeation has obtained. • Quality of TPB is a very important factor for efficient T-permeating reduction.

  1. Multilayered nanoclusters of platinum and gold: insights on electrodeposition pathways, electrocatalysis, surface and bulk compositional properties

    Mkwizu, TS

    2013-06-01

    Full Text Available Electrochemical, surface and bulk compositional properties of multilayered nanoclusters of Pt and Au, electrochemically deposited on glassy carbon under conditions involving sequential surface–limited redox–replacement reactions (performed at open...

  2. Ab-initio investigations of the electronic properties of bulk wurtzite Beryllia and its derived nanofilms

    Goumri-Said, Souraya; Kanoun, Mohammed

    2010-01-01

    In this Letter we investigate the electronic properties of the bulk and the nanofilm BeO in wurtzite structure. We performed a first-principles pseudo-potential method within the generalized gradient approximation. We will give more importance

  3. STRUCTURAL CHARACTERIZATION AND GAS PERMEATION PROPERTIES OF POLYETHERIMIDE (PEI/ZEOLITIC IMIDAZOLATE (ZIF-11 MIXED MATRIX MEMBRANES

    Mehtap Şafak Boroğlu

    2016-06-01

    Full Text Available In this study, the preparation of polyetherimide (PEI-Ultem1000/ZIF-11 mixed matrix membranes was studied in various ZIF-11 nanoparticles loadings (0, 10, 15, 20, and 30 wt.%. The newly synthesized ZIF-11 nanoparticles with an average particle size of ~280 nm were integrated in PEI membranes as novel mixed matrix membranes (MMMs. The effect of ZIF-11 loading was scrutinised for H2, CO2, and CH4 gas separation performance at 35 °C and 4 bar. The incorporation of ZIF-11 nanoparticles improved the gas permeation properties of the MMMs with an increase in ZIF-11 loading. As the ZIF-11 loading increased up to 20 wt.%, the permeability of H2 and CO2 increased to four times higher than that of the pure polymer. Moderate increase of CH4 permeability was also recorded. At higher loadings above 20 wt.%, the permeability decreased for all gases and the CO2/CH4, and H2/CH4 selectivities increased consistent with the ZIF-11 loading.

  4. Gas Permeation Properties of Soluble Aromatic Polyimides Based on 4-Fluoro-4,4'-Diaminotriphenylmethane

    Diego Guzmán-Lucero

    2015-04-01

    Full Text Available A series of new organic polyimides were synthesized from 4-fluoro-4'4"-diaminotriphenylmethane and four different aromatic dianhydrides through a one-step, high-temperature, direct polycondensation in m-cresol at 180–200 °C, resulting in the formation of high-molecular-weight polyimides (inherent viscosities ~ 1.0–1.3 dL/g. All the resulting polyimides exhibited good thermal stability with initial decomposition temperatures above 434 °C, glass-transition temperatures between 285 and 316 °C, and good solubility in polar aprotic solvents. Wide-angle X-ray scattering data indicated that the polyimides were amorphous. Dense membranes were prepared by solution casting and solvent evaporation to evaluate their gas transport properties (permeability, diffusivity, and solubility coefficients toward pure hydrogen, helium, oxygen, nitrogen, methane, and carbon dioxide gases. In general, the gas permeability was increased as both the fractional free volume and d-spacing were also increased. A good combination of permeability and selectivity was promoted efficiently by the bulky hexafluoroisopropylidene and 4-fluoro-phenyl groups introduced into the polyimides. The results indicate that the gas transport properties of these films depend on both the structure of the anhydride moiety, which controls the intrinsic intramolecular rigidity, and the 4-fluoro-phenyl pendant group, which disrupts the intermolecular packing.

  5. 129Xe NMR spectroscopy in microporous solids: The effect of bulk properties

    Ripmeester, John A.; Ratcliffe, Christopher I.

    1993-01-01

    In this contribution we point out a number of factors related to the bulk properties of microporous solids which must be taken into account in order first of all to obtain meaningful 129 Xe NMR spectral data, and secondly to interpret the data properly. This sensitivity to bulk properties is especially important for microporous solids where there is little or no barrier to xenon passage from inside the particle to the interparticle space. We examine the effect of particle size, powder bulk density and particle anisotropy, and also the effect of low thermal conductivity of low density powders

  6. Optical and scintillation properties of bulk ZnO crystal

    Yanagida, Takayuki [Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu, Kitakyushu 808-0196 (Japan); Fujimoto, Yutaka; Kurosawa, Shunsuke [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Yamanoi, Kohei; Sarukura, Nobuhiko [Institute of Laser Engineering, Osaka University, Suita, Osaka 565-0871 (Japan); Kano, Masataka; Wakamiya, Akira [Daishinku Corporation, 1389 Shinzaike, Hiraoka-cho, Kakogawa, Hyogo 675-0194 (Japan)

    2012-12-15

    Single crystal bulk ZnO scintillator grown by the hydrothermal method was tested on its scintillation performances. In X-ray induced radio luminescence spectrum, it exhibited two intense emission peaks at 400 and 550 nm. The former was ascribed to the free and bound exciton related luminescence and the latter to oxygen vacancy related one, respectively. X-ray induced scintillation decay time of the exciton related emission measured by the pulse X-ray streak camera system resulted {proportional_to} 4 ns. Finally, the light yield under {sup 241}Am 5.5 MeV {alpha}-ray was examined and it resulted {proportional_to} 500 ph/5.5 MeV-{alpha}.(copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Designing of Bulk Nano-Structures with Enhanced Thermoelectric Properties

    Kanatzidis, Mercouri; Hogan, Timothy; Murray, Chris

    2007-01-01

    .... K2Bi8Se13 is a member of this series and was found to be a promising thermoelectric. The charge transport properties were studied under pressure, where a significant increase in the power factor was observed...

  8. Designing of Bulk Nano-Structures With Enhanced Thermoelectric Properties

    Kanatzidis, Mercouri G

    2007-01-01

    .... K2Bi8Se13 is a member of this series and was found to be a promising thermoelectric. The charge transport properties were studied under pressure, where a significant increase in the power factor was observed...

  9. Simplified tritium permeation model

    Longhurst, G.R.

    1993-01-01

    In this model I seek to provide a simplified approach to solving permeation problems addressed by TMAP4. I will assume that there are m one-dimensional segments with thickness L i , i = 1, 2, hor-ellipsis, m, joined in series with an implantation flux, J i , implanting at the single depth, δ, in the first segment. From material properties and heat transfer considerations, I calculate temperatures at each face of each segment, and from those temperatures I find local diffusivities and solubilities. I assume recombination coefficients K r1 and K r2 are known at the upstream and downstream faces, respectively, but the model will generate Baskes recombination coefficient values on demand. Here I first develop the steady-state concentration equations and then show how trapping considerations can lead to good estimates of permeation transient times

  10. Flux Trapping Properties of Bulk HIGH-TC Superconductors in Static Field-Cooling Magnetization

    Deng, Z.; Tsuzuki, K.; Miki, M.; Felder, B.; Hara, S.; Izumi, M.

    2013-06-01

    The trapping process and saturation effect of trapped magnetic flux of bulk high-temperature superconductors by static field-cooling magnetization (FCM) are reported in the paper. With a cryogenic Bell Hall sensor attached on the center of the bulk surface, the synchronous magnetic signals were recorded during the whole magnetization process. It enables us to know the flux trapping behavior since the removal of the excitation field, as well as the subsequent flux relaxation phenomenon and the flux dissipation in the quench process of the bulk sample. With the help of flux mapping techniques, the relationship between the trapped flux and the applied field was further investigated; the saturation effect of trapped flux was discussed by comparing the peak trapped field and total magnetic flux of the bulk sample. These studies are useful to understand the basic flux trapping properties of bulk superconductors.

  11. Bulk and mechanical properties of the Paintbrush tuff recovered from borehole USW NRG-6: Data report

    Martin, R.J.; Boyd, P.J.; Noel, J.S.; Price, R.H.

    1994-11-01

    Experimental results are presented for bulk and mechanical properties measurements on specimens of the Paintbrush tuff recovered from borehole USW NRG-6 at Yucca Mountain, Nevada. Measurements have been performed on four thermal/mechanical units, TCw, PTn, TSw1 and TSw2. On each specimen the following bulk properties have been reported: dry bulk density, saturated bulk density, average grain density, and porosity. Unconfined compression to failure, confined compression to failure, and indirect tensile strength tests were performed on selected specimens recovered from the borehole. In addition, compressional and shear wave velocities were measured on specimens designated for unconfined compression and confined compression experiments. Measurements were conducted at room temperature on nominally water saturated specimens; however, some specimens of PTn were tested in a room dry condition. The nominal strain rate for the fracture experiments was 10 -5 s -1

  12. Crystallinity and flux pinning properties of MgB2 bulks

    Yamamoto, A.; Shimoyama, J.; Ueda, S.; Katsura, Y.; Iwayama, I.; Horii, S.; Kishio, K.

    2006-01-01

    The relationship between flux pinning properties and crystallinity of MgB 2 bulks was systematically studied. Improved flux pinning properties under high fields were observed for samples with low crystallinity. Increased impurity scattering due to strain and defects in lattice corresponding to the degraded crystallinity was considered to enhance flux pinning strength at grain boundaries. Low-temperature synthesis and carbon substitution were confirmed to be effective for degrading crystallinity of MgB 2 bulks, resulting in high critical current properties under high fields

  13. Chemical, electronic, and magnetic structure of LaFeCoSi alloy: Surface and bulk properties

    Lollobrigida, V. [Dipartimento di Scienze, Università Roma Tre, I-00146 Rome (Italy); Dipartimento di Matematica e Fisica, Università Roma Tre, I-00146 Rome (Italy); Basso, V.; Kuepferling, M.; Coïsson, M.; Olivetti, E. S.; Celegato, F. [Istituto Nazionale di Ricerca Metrologica (INRIM), I-10135 Torino (Italy); Borgatti, F. [CNR, Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), I-40129 Bologna (Italy); Torelli, P.; Panaccione, G. [CNR, Istituto Officina dei Materiali (IOM), Lab. TASC, I-34149 Trieste (Italy); Tortora, L. [Laboratorio di Analisi di Superficie, Dipartimento di Matematica e Fisica, Università Roma Tre, I-00146 Rome (Italy); Dipartimento di Ingegneria Meccanica, Università Tor Vergata, I-00133 Rome (Italy); Stefani, G.; Offi, F. [Dipartimento di Scienze, Università Roma Tre, I-00146 Rome (Italy)

    2014-05-28

    We investigate the chemical, electronic, and magnetic structure of the magnetocaloric LaFeCoSi compound with bulk and surface sensitive techniques. We put in evidence that the surface retains a soft ferromagnetic behavior at temperatures higher than the Curie temperature of the bulk due to the presence of Fe clusters at the surface only. This peculiar magnetic surface effect is attributed to the exchange interaction between the ferromagnetic Fe clusters located at the surface and the bulk magnetocaloric alloy, and it is used here to monitor the magnetic properties of the alloy itself.

  14. Chemical, electronic, and magnetic structure of LaFeCoSi alloy: Surface and bulk properties

    Lollobrigida, V.; Basso, V.; Borgatti, F.; Torelli, P.; Kuepferling, M.; Coïsson, M.; Olivetti, E. S.; Celegato, F.; Tortora, L.; Stefani, G.; Panaccione, G.; Offi, F.

    2014-05-01

    We investigate the chemical, electronic, and magnetic structure of the magnetocaloric LaFeCoSi compound with bulk and surface sensitive techniques. We put in evidence that the surface retains a soft ferromagnetic behavior at temperatures higher than the Curie temperature of the bulk due to the presence of Fe clusters at the surface only. This peculiar magnetic surface effect is attributed to the exchange interaction between the ferromagnetic Fe clusters located at the surface and the bulk magnetocaloric alloy, and it is used here to monitor the magnetic properties of the alloy itself.

  15. Chemical, electronic, and magnetic structure of LaFeCoSi alloy: Surface and bulk properties

    Lollobrigida, V.; Basso, V.; Kuepferling, M.; Coïsson, M.; Olivetti, E. S.; Celegato, F.; Borgatti, F.; Torelli, P.; Panaccione, G.; Tortora, L.; Stefani, G.; Offi, F.

    2014-01-01

    We investigate the chemical, electronic, and magnetic structure of the magnetocaloric LaFeCoSi compound with bulk and surface sensitive techniques. We put in evidence that the surface retains a soft ferromagnetic behavior at temperatures higher than the Curie temperature of the bulk due to the presence of Fe clusters at the surface only. This peculiar magnetic surface effect is attributed to the exchange interaction between the ferromagnetic Fe clusters located at the surface and the bulk magnetocaloric alloy, and it is used here to monitor the magnetic properties of the alloy itself.

  16. Analysis of the hydrogen permeation properties of TiN-TiC bilayers deposited on martensitic stainless steel

    Checchetto, R.; Horino, Y.; Benamati, G.

    1996-01-01

    The efficiency of TiN-TiC bilayer coatings, deposited by ion-beam-assisted deposition on martensitic steel, as a hydrogen permeation barrier was investigated by a gas phase method; the hydrogen permeability in the TiN-TiC bilayers is very low, at least 10 4 times lower than in the steel substrate in the temperature interval 470-570 K. Possible physical mechanisms, responsible for the reduced permeability of the ceramic bilayers, are discussed. In particular, from our experimental results, it can be concluded that chemisorption and/or hydrogen jumping from surface sites to the first subsurface atomic layer represents the hydrogen permeation limiting process. (orig.)

  17. Fabrication of Bi2223 bulks with high critical current properties sintered in Ag tubes

    Takeda, Yasuaki, E-mail: ytakeda@g.ecc.u-tokyo.ac.jp [Department of Applied Chemistry, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Shimoyama, Jun-ichi; Motoki, Takanori [Department of Physics and Mathematics, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5258 (Japan); Kishio, Kohji [Department of Applied Chemistry, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Nakashima, Takayoshi; Kagiyama, Tomohiro; Kobayashi, Shin-ichi; Hayashi, Kazuhiko [Sumitomo Electric Industries, Ltd. 1-1-3 Shimaya, Konohana-ku, Osaka 554-0024 (Japan)

    2017-03-15

    Highlights: • Fabrication conditions of Bi2223 bulks was reconsidered in terms of high J{sub c}. • Pressure of uniaxial pressing and heat treatment conditions were investigated. • The best sample showed higher J{sub c} than that of practically used Bi2223 bulks. - Abstract: Randomly grain oriented Bi2223 sintered bulks are one of the representative superconducting materials having weak-link problem due to very short coherence length particularly along the c-axis, resulting in poor intergrain J{sub c} properties. In our previous studies, sintering and/or post-annealing under moderately reducing atmospheres were found to be effective for improving grain coupling in Bi2223 sintered bulks. Further optimizations of the synthesis process for Bi2223 sintered bulks were attempted in the present study to enhance their intergrain J{sub c}. Effects of applied pressure of uniaxial pressing and sintering conditions on microstructure and superconducting properties have been systematically investigated. The best sample showed intergrain J{sub c} of 2.0 kA cm{sup −2} at 77 K and 8.2 kA cm{sup −2} at 20 K, while its relative density was low ∼65%. These values are quite high as for a randomly oriented sintered bulk of cuprate superconductors.

  18. Evaluation of mechanical properties of Dy123 bulk superconductors by 3-point bending tests

    Katagiri, K.; Hatakeyama, Y.; Sato, T.; Kasaba, K.; Shoji, Y.; Murakami, A.; Teshima, H.; Hirano, H.

    2006-01-01

    In order to evaluate the mechanical properties, such as Young's modulus and strength, of Dy123 bulk superconductors and those with 10 wt.% Ag 2 O, we performed 3-point bending tests at room (RT) and liquid nitrogen temperatures (LNT) using specimens cut from the bulks. The Young's modulus and the bending strength increased with decrease in temperature. In the tests loading in the direction of c-axis and ones perpendicular to it, Young's moduli were almost comparable at both RT and LNT. Although the strengths for both orientations were also comparable at LNT, those at RT were different. Young's moduli loaded in the direction of c-axis for Ag 2 O added bulk specimens, 127 GPa in average at RT, were almost comparable to those without Ag 2 O, and 134 GPa at LNT, were slightly lower than those without Ag 2 O. On the other hand, the strengths at both RT and LNT were enhanced by 20% by the Ag addition. The mechanical properties of Dy123 bulks without Ag 2 O were compared with those of Y123 bulks obtained previously. The Young's modulus for loading in the direction of c-axis was slightly lower, and the strength was comparable to those in Y123 bulks, respectively

  19. Structure and property evaluation of a vacuum plasma sprayed nanostructured tungsten-hafnium carbide bulk composite

    Rea, K.E.; Viswanathan, V.; Kruize, A.; Hosson, J.Th.M. de; O'Dell, S.; McKechnie, T.; Rajagopalan, S.; Vaidyanathan, R.; Seal, S.

    2008-01-01

    Vacuum plasma spray (VPS) forming of tungsten-based metal matrix nanocomposites (MMCs) has shown to be a cost effective and time saving method for the formation of bulk monolithic nanostructured thermo-mechanical components. Spray drying of powder feedstock appears to have a significant effect on the improved mechanical properties of the bulk nanocomposite. The reported elastic modulus of the nanocomposite nearly doubles due to the presence of HfC nano particulates in the W matrix. High resolution transmission electron microscopy (HRTEM) revealed the retention of nanostructures at the select process conditions and is correlated with the enhanced mechanical properties of the nanocomposite

  20. Thermal, spectral, and surface properties of LED light-polymerized bulk fill resin composites.

    Pişkin, Mehmet Burçin; Atalı, Pınar Yılmaz; Figen, Aysel Kantürk

    2015-02-01

    The aim of this study was to evaluate the thermal, spectral, and surface properties of four different bulk fill materials – SureFil SDR (SDR, Dentsplay DETREY), QuixFil (QF, Dentsplay DETREY), X-tra base (XB, Voco) X-tra fil (XF, Voco) – polymerized by light-emitting diode (LED). Resin matrix, filler type, size and amount, and photoinitiator types influence the degree of conversion. LED-cured bulk fill composites achieved sufficient polymerization. Scanning electron microscope (SEM) analysis revealed different patterns of surface roughness, depending on the composite material. Bulk fill materials showed surface characteristics similar to those of nanohybrid composites. Based on the thermal analysis results, glass transition (T(g)) and initial degradation (T(i)) temperatures changed depending on the bulk fill resin composites.

  1. Improvement of the mechanical properties of bulk superconductors; Jushiganshin niyoru baruku chodendotai no kikaitekitokusei no kaizen

    Tomita, M; Murakami, M [Superconductivity Research Laboratory, Tokyo (Japan)

    1999-11-25

    Large single-grain bulk rare earth element (RE)-Ba-Cu-O superconductors can trip large fields exceeding several teslas and thus can function as very strong quasi-permanent magnets. However, the maximum trapped field is essentially limited by the mechanical strength of the bulk superconductors. The stress produced by refrigeration sometimes causes cracking. A large electromagnetic force also acts on superconductors when they trap large magnetic fields, and this occasionally leads to device failure. We have recently found that epoxy resin can penetrate into bulk superconductors under certain conditions. Microstructural observation revealed that microcracks as well as porosities can be impregnated with epoxy resin, which greatly improves the mechanical properties of bulk RE-Ba-Cu-O and thus results in the improvement of field trapping capability. (author)

  2. Alternative Measurement Configurations for Extracting Bulk Optical Properties Using an Integrating Sphere Setup.

    Thennadil, Suresh N; Chen, Yi-Chieh

    2017-02-01

    The usual approach for estimating bulk optical properties using an integrating sphere measurement setup is by acquiring spectra from three measurement modes namely collimated transmittance (T c ), total transmittance (T d ), and total diffuse reflectance (R d ), followed by the inversion of these measurements using the adding-doubling method. At high scattering levels, accurate acquisition of T c becomes problematic due to the presence of significant amounts of forward-scattered light in this measurement which is supposed to contain only unscattered light. In this paper, we propose and investigate the effectiveness of using alternative sets of integrating sphere measurements that avoid the use of T c and could potentially increase the upper limit of concentrations of suspensions at which bulk optical property measurements can be obtained in the visible-near-infrared (Vis-NIR) region of the spectrum. We examine the possibility of replacing T c with one or more reflectance measurements at different sample thicknesses. We also examine the possibility of replacing both the collimated (T c ) and total transmittance (T d ) measurements with reflectance measurements taken from different sample thicknesses. The analysis presented here indicates that replacing T c with a reflectance measurement can reduce the errors in the bulk scattering properties when scattering levels are high. When only multiple reflectance measurements are used, good estimates of the bulk optical properties can be obtained when the absorption levels are low. In addition, we examine whether there is any advantage in using three measurements instead of two to obtain the reduced bulk scattering coefficient and the bulk absorption coefficient. This investigation is made in the context of chemical and biological suspensions which have a much larger range of optical properties compared to those encountered with tissue.

  3. Finite element analysis and simulation of rheological properties of bulk molding compound (BMC)

    Ergin, M. Fatih; Aydin, Ismail

    2013-12-01

    Bulk molding compound (BMC) is one of the important composite materials with various engineering applications. BMC is a thermoset plastic resin blend of various inert fillers, fiber reinforcements, catalysts, stabilizers and pigments that form a viscous, molding compound. Depending on the end-use application, bulk molding compounds are formulated to achieve close dimensional control, flame and scratch resistance, electrical insulation, corrosion and stain resistance, superior mechanical properties, low shrink and color stability. Its excellent flow characteristics, dielectric properties, and flame resistance make this thermoset material well-suited to a wide variety of applications requiring precision in detail and dimensions as well as high performance. When a BMC is used for these purposes, the rheological behavior and properties of the BMC is the main concern. In this paper, finite element analysis of rheological properties of bulk molding composite material was studied. For this purpose, standard samples of composite material were obtained by means of uniaxial hot pressing. 3 point flexural tests were then carried out by using a universal testing machine. Finite element analyses were then performed with defined material properties within a specific constitutive material behavior. Experimental and numerical results were then compared. Good correlation between the numerical simulation and the experimental results was obtained. It was expected with this study that effects of various process parameters and boundary conditions on the rheological behavior of bulk molding compounds could be determined by means of numerical analysis without detailed experimental work.

  4. Oxygen permeation properties of dense Bi1.5Er0.5O3-Ag cermet membranes

    ten Elshof, Johan E.; Nguyen, N.Q.; den Otter, M.W.; Bouwmeester, Henricus J.M.

    1997-01-01

    Oxygen permeation experiments were performed on dense mixed-conducting ceramic-metal composite membranes (thickness 0.2 to 2 mm) Bi1.5Er0.5O3-Ag with 10.0, 27.8, and 40.0 volume percent (v/o) silver, respectively, in the temperature range 873 to 993 K and oxygen partial pressure range 10–3.5 to 1

  5. Effect of oxidative enzymes on bulk rheological properties of wheat flour doughs

    Dunnewind, B.; Vliet, T. van; Orsel, R.

    2002-01-01

    The use of enzymes such as peroxidases or glucose oxidase instead of chemical oxidants is a very interesting option for improving breadmaking performance of doughs. In this study the effect of such enzymes on bulk rheological properties of dough was quantified and their influence on the polymer

  6. Effect of Oxidative Enzymes on Bulk Rheological Properties of Wheat Flour Doughs

    Dunnewind, B.; Vliet, van T.; Orsel, R.

    2002-01-01

    The use of enzymes such as peroxidases or glucose oxidase instead of chemical oxidants is a very interesting option for improving breadmaking performance of doughs. In this study the effect of such enzymes on bulk rheological properties of dough was quantified and their influence on the polymer

  7. On Diffusion and Permeation

    Peppin, Stephen S. L.

    2009-01-01

    concentrations they form a nearly rigid porous glass through which the fluid permeates. The theoretically determined pressure drop is nonlinear in the diffusion regime and linear in the permeation regime, in quantitative agreement with experimental measurements

  8. Pion condensation in a theory consistent with bulk properties of nuclear matter

    Glendenning, N.K.

    1980-01-01

    A relativistic field theory of nuclear matter is solved for the self-consistent field strengths inthe mean-field approximation. The theory is constrained to reproduce the bulk properties of nuclear matter. A weak pion condensate is compatible with this constraint. At least this is encouraging as concerns the possible existence of a new phase of nuclear matter. In contrast, the Lee-Wick density isomer is probably not compatible with the properties of nuclear matter. 3 figures

  9. Transport mechanisms through PE-CVD coatings: influence of temperature, coating properties and defects on permeation of water vapour

    Kirchheim, Dennis; Jaritz, Montgomery; Hopmann, Christian; Dahlmann, Rainer; Mitschker, Felix; Awakowicz, Peter; Gebhard, Maximilian; Devi, Anjana; Brochhagen, Markus; Böke, Marc

    2017-01-01

    Gas transport mechanisms through plastics are usually described by the temperature-dependent Arrhenius-model and compositions of several plastic layers are represented by the CLT. When it comes to thin films such as plasma-enhanced chemical vapour deposition (PE-CVD) or plasma-enhanced atomic layer deposition (PE-ALD) coatings on substrates of polymeric material, a universal model is lacking. While existing models describe diffusion through defects, these models presume that permeation does not occur by other means of transport mechanisms. This paper correlates the existing transport models with data from water vapour transmission experiments. (paper)

  10. Mechanical properties of nano and bulk Fe pillars using molecular dynamics and dislocation dynamics simulation

    S. K. Deb Nath

    2017-10-01

    Full Text Available Using molecular dynamics simulation, tension and bending tests of a Fe nanopillar are carried out to obtain its Young’s modulus and yield strength. Then the comparative study of Young’s modulus and yield strength of a Fe nanopillar under bending and tension are carried out varying its diameter in the range of diameter 1-15nm. We find out the reasons why bending Young’s modulus and yield strength of a Fe nanopillar are higher than those of tension Young’s modulus and yield strength of a Fe nanopillar. Using the mobility parameters of bulk Fe from the experimental study [N. Urabe and J. Weertman, Materials Science and Engineering 18, 41 (1975], its temperature dependent stress-strain relationship, yield strength and strain hardening modulus are obtained from the dislocation dynamics simulations. Strain rate dependent yield strength and strain hardening modulus of bulk Fe pillars under tension are studied. Temperature dependent creep behaviors of bulk Fe pillars under tension are also studied. To verify the soundness of the present dislocation dynamics studies of the mechanical properties of bulk Fe pillars under tension, the stress vs. strain relationship and dislocation density vs. strain of bulk Fe pillars obtained by us are compared with the published results obtained by S. Queyreau, G. Monnet, and B. Devincre, International Journal of Plasticity 25, 361 (2009.

  11. Proton exchange membranes from sulfonated polyetheretherketone and sulfonated polyethersulfone-cardo blends: Conductivity, water sorption and permeation properties

    Li, Yongli; Nguyen, Quang Trong; Schaetzel, Pierre; Lixon-Buquet, Camille; Colasse, Laurent; Ratieuville, Vincent

    2013-01-01

    Five blend membranes were prepared by solvent evaporation from solutions of the synthesized sulfonated polyetheretherketone (SPEEK) and sulfonated polyethersulfone-cardo (SPESc). Their ion exchange capacity and degree of sulfonation determined by acid–base titration and by thermogravimetric analysis were consistent. The blends glass transition behavior obtained by differential scanning calorimetry suggests that the two sulfonated polymers are compatible in the whole composition range. The values of the activation energy for proton transport determined by conductivity measurements on the SPEEK-based blend membranes were in the range of 13–34 kJ mol −1 , which suggest a mixed transport mechanism that involves both proton jumps on ionic sites and water of hydration and diffusion of proton–water complex in hydrophilic domains. The water vapor sorption in the membranes exhibits sigmoid-shape isotherms which were well fitted by the “new dual mode sorption” model, and the fitted parameters values were successfully used to model the change in the water permeation flux with the upstream water activity using the first Fick's diffusion equation. The fast increase in the permeation flux beyond a critical value of activity (0.5) was owing to the exponential concentration-dependent diffusion coefficient. These modelings allowed us to show a strong increase in the limit diffusion coefficient of water and a decrease in the water-diffusion plasticization coefficient with the SPEEK content in the polymer blends

  12. Mechanical properties of Fe-Ni-Cr-Si-B bulk glassy alloy

    Lee, Kee Ahn; Kim, Yong Chan; Kim, Jung Han; Lee, Chong Soo; Namkung, Jung; Kim, Moon Chul

    2007-01-01

    The mechanical properties and crystallization behavior of new Fe-Ni-Cr-Si-B-based bulk glassy alloys were investigated. The suitability of the continuous roll casting method for the production of bulk metallic glass (BMG) sheets in such alloy systems was also examined. BMG samples (Fe-Ni-Cr-Si-B, Fe-Ni-Zr-Cr-Si-B, Fe-Ni-Zr-Cr-W-Si-B) in amorphous strip, cylindrical, and sheet forms were prepared through melt spinning, copper mold casting, and twin roll strip casting, respectively. Fe-Ni-Cr-Si-B alloy exhibited compressive strength of up to 2.93 GPa and plastic strain of about 1.51%. On the other hand, the Fe-Ni-Zr-Cr-Si-B, composite-type bulk sample with diameter of 2.0 mm showed remarkable compressive plastic strain of about 4.03%. The addition of zirconium was found to enhance the homogeneous precipitation of nanocrystalline less than 7 nm and to develop a hybrid-composite microstructure with increasing sample thickness. Twin roll strip casting was successfully applied to the fabrication of sheets in Fe-Ni-Cr-Si-B-based BMGs. The combined characteristics of high mechanical properties and ease of microstructure control proved to be promising in terms of the future progress of structural bulk amorphous alloys

  13. Mechanical properties of Fe-Ni-Cr-Si-B bulk glassy alloy

    Lee, Kee Ahn [School of Advanced Materials Engineering, Andong National University, Andong 760-749 (Korea, Republic of)]. E-mail: keeahn@andong.ac.kr; Kim, Yong Chan [New Metals Research Team, RIST, Pohang 790-330 (Korea, Republic of); Kim, Jung Han [Center for Advanced Aerospace materials, POSTECH, Pohang 790-784 (Korea, Republic of); Lee, Chong Soo [Center for Advanced Aerospace materials, POSTECH, Pohang 790-784 (Korea, Republic of); Namkung, Jung [New Metals Research Team, RIST, Pohang 790-330 (Korea, Republic of); Kim, Moon Chul [New Metals Research Team, RIST, Pohang 790-330 (Korea, Republic of)

    2007-03-25

    The mechanical properties and crystallization behavior of new Fe-Ni-Cr-Si-B-based bulk glassy alloys were investigated. The suitability of the continuous roll casting method for the production of bulk metallic glass (BMG) sheets in such alloy systems was also examined. BMG samples (Fe-Ni-Cr-Si-B, Fe-Ni-Zr-Cr-Si-B, Fe-Ni-Zr-Cr-W-Si-B) in amorphous strip, cylindrical, and sheet forms were prepared through melt spinning, copper mold casting, and twin roll strip casting, respectively. Fe-Ni-Cr-Si-B alloy exhibited compressive strength of up to 2.93 GPa and plastic strain of about 1.51%. On the other hand, the Fe-Ni-Zr-Cr-Si-B, composite-type bulk sample with diameter of 2.0 mm showed remarkable compressive plastic strain of about 4.03%. The addition of zirconium was found to enhance the homogeneous precipitation of nanocrystalline less than 7 nm and to develop a hybrid-composite microstructure with increasing sample thickness. Twin roll strip casting was successfully applied to the fabrication of sheets in Fe-Ni-Cr-Si-B-based BMGs. The combined characteristics of high mechanical properties and ease of microstructure control proved to be promising in terms of the future progress of structural bulk amorphous alloys.

  14. Microstructure and tensile properties of bulk nanostructured aluminum/graphene composites prepared via cryomilling

    Li, J.L., E-mail: ljlhpu123@163.com; Xiong, Y.C.; Wang, X.D.; Yan, S.J.; Yang, C.; He, W.W.; Chen, J.Z.; Wang, S.Q.; Zhang, X.Y.; Dai, S.L.

    2015-02-25

    In order to develop high strength metal–matrix composites with acceptable ductility, bulk nanostructured aluminum–matrix composites reinforced with graphene nanoflakes were fabricated by cryomilling and hot extrusion processes. Microstructure and mechanical properties were characterized and determined using transmission electron microscopy, electron dispersion spectroscopy, as well as static tensile tests. The results show that, with an addition of only 0.5 wt% graphene nanoflakes, the bulk nanostructured aluminum/graphene composite exhibited increased strength and unsubdued ductility over pure aluminum. Besides, the mechanical properties of the composites with higher content of graphene nanoflakes were also measured and investigated. Above 1.0 wt% of graphene nanoflakes, however, this strengthening effect sharply dropped due to the clustering of graphene nanoflakes. Furthermore, the optimal addition of graphene nanoflakes into the nanocrystalline aluminum matrix was calculated and discussed.

  15. Titania doping effect on superconducting properties of MgB{sub 2} bulk samples

    Serrano, G; Serquis, A [Institute Balseiro - Centra Atomico Bariloche and CONICET, (8400) S. C. de Bariloche, Rio Negro (Argentina); Bridoux, G, E-mail: serranog@ib.cnea.gov.a [Institute Balseiro - Centra Atomico Bariloche, (8400) S. C. de Bariloche, Rio Negro (Argentina)

    2009-05-01

    In this work we study the microstructural and superconducting properties of doped and undoped bulk MgB{sub 2} samples prepared by solid-state reaction, with 0 and 2.5 %at. nominal TiO{sub 2} nanotubes contents, annealed at different temperatures in the 750-900 deg. C range. We discuss the T{sub c}, J{sub c} and H{sub c2} performance and their correlation with the different synthesis parameters.

  16. Delignified and Densified Cellulose Bulk Materials with Excellent Tensile Properties for Sustainable Engineering.

    Frey, Marion; Widner, Daniel; Segmehl, Jana S; Casdorff, Kirstin; Keplinger, Tobias; Burgert, Ingo

    2018-02-07

    Today's materials research aims at excellent mechanical performance in combination with advanced functionality. In this regard, great progress has been made in tailoring the materials by assembly processes in bottom-up approaches. In the field of wood-derived materials, nanocellulose research has gained increasing attention, and materials with advanced properties were developed. However, there are still unresolved issues concerning upscaling for large-scale applications. Alternatively, the sophisticated hierarchical scaffold of wood can be utilized in a top-down approach to upscale functionalization, and one can profit at the same time from its renewable nature, CO 2 storing capacity, light weight, and good mechanical performance. Nevertheless, for bulk wood materials, a wider multipurpose industrial use is so far impeded by concerns regarding durability, natural heterogeneity as well as limitations in terms of functionalization, processing, and shaping. Here, we present a novel cellulose bulk material concept based on delignification and densification of wood resulting in a high-performance material. A delignification process using hydrogen peroxide and acetic acid was optimized to delignify the entire bulk wooden blocks and to retain the highly beneficial structural directionality of wood. In a subsequent step, these cellulosic blocks were densified in a process combining compression and lateral shear to gain a very compact cellulosic material with entangled fibers while retaining unidirectional fiber orientation. The cellulose bulk materials obtained by different densification protocols were structurally, chemically, and mechanically characterized revealing superior tensile properties compared to native wood. Furthermore, after delignification, the cellulose bulk material can be easily formed into different shapes, and the delignification facilitates functionalization of the bioscaffold.

  17. First-principles studies of electronic, transport and bulk properties of pyrite FeS2

    Dipendra Banjara

    2018-02-01

    Full Text Available We present results from first principle, local density approximation (LDA calculations of electronic, transport, and bulk properties of iron pyrite (FeS2. Our non-relativistic computations employed the Ceperley and Alder LDA potential and the linear combination of atomic orbitals (LCAO formalism. The implementation of the LCAO formalism followed the Bagayoko, Zhao, and Williams (BZW method, as enhanced by Ekuma and Franklin (BZW-EF. We discuss the electronic energy bands, total and partial densities of states, electron effective masses, and the bulk modulus. Our calculated indirect band gap of 0.959 eV (0.96, using an experimental lattice constant of 5.4166 Å, at room temperature, is in agreement with the measured indirect values, for bulk samples, ranging from 0.84 eV to 1.03 ± 0.05 eV. Our calculated bulk modulus of 147 GPa is practically in agreement with the experimental value of 145 GPa. The calculated, partial densities of states reproduced the splitting of the Fe d bands to constitute the dominant upper most valence and lower most conduction bands, separated by the generally accepted, indirect, experimental band gap of 0.95 eV.

  18. Preparation and magnetic properties of anisotropic bulk MnBi/NdFeB hybrid magnets

    Ma, Y.L.; Liu, X.B.; Nguyen, V.V.; Poudyal, N.; Yue, M.; Liu, J.P.

    2016-01-01

    Anisotropic hybrid bulk magnets of MnBi/NdFeB with different composition ratio have been prepared with starting MnBi and Nd 2 Fe 14 B powders as well as epoxy resin as a binder in case it is needed to form bulk samples. It has been found that the ratio between the two phases in content has a remarkable influence on the magnetic properties, the thermal stability and the density of the bulk magnets. With increasing MnBi content the binder addition can be reduced. When the MnBi content is larger than 30 wt%, no binder is needed. On the other hand, the coercivity and saturation magnetization were increased significantly with increasing NdFeB content. When the NdFeB content was increased from 0% to 50%, the maximum energy product was enhanced from 4.7 to 10.0 MGOe, respectively. The energy product then decreased gradually with the NdFeB content due to the reduced density of the hybrid magnet. The thermal stability measurements showed that the temperature coefficient of coercivity grew with the MnBi content and became positive with MnBi=80 wt%. - Highlights: • Anisotropic bulk hybrid MnBi/NdFeB magnets were prepared. • MnBi content affected the density and coercivity temperature coefficient positively. • An energy product (BH) max of 10 MGOe was obtained at NdFeB content of 50 wt%.

  19. Preparation and magnetic properties of anisotropic bulk MnBi/NdFeB hybrid magnets

    Ma, Y.L. [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States); College of Metallurgical and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331 (China); Liu, X.B.; Nguyen, V.V.; Poudyal, N. [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States); Yue, M. [College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124 (China); Liu, J.P., E-mail: pliu@uta.edu [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States)

    2016-08-01

    Anisotropic hybrid bulk magnets of MnBi/NdFeB with different composition ratio have been prepared with starting MnBi and Nd{sub 2}Fe{sub 14}B powders as well as epoxy resin as a binder in case it is needed to form bulk samples. It has been found that the ratio between the two phases in content has a remarkable influence on the magnetic properties, the thermal stability and the density of the bulk magnets. With increasing MnBi content the binder addition can be reduced. When the MnBi content is larger than 30 wt%, no binder is needed. On the other hand, the coercivity and saturation magnetization were increased significantly with increasing NdFeB content. When the NdFeB content was increased from 0% to 50%, the maximum energy product was enhanced from 4.7 to 10.0 MGOe, respectively. The energy product then decreased gradually with the NdFeB content due to the reduced density of the hybrid magnet. The thermal stability measurements showed that the temperature coefficient of coercivity grew with the MnBi content and became positive with MnBi=80 wt%. - Highlights: • Anisotropic bulk hybrid MnBi/NdFeB magnets were prepared. • MnBi content affected the density and coercivity temperature coefficient positively. • An energy product (BH){sub max} of 10 MGOe was obtained at NdFeB content of 50 wt%.

  20. EFFECT OF THE TEMPERATURE ON THE FRICTION AND WEAR PROPERTIES OF BULK AMORPHOUS ALLOY

    DAWIT ZENEBE SEGU; PYUNG HWANG; SEOCK-SAM KIM

    2014-01-01

    The present paper report the results of an experimental investigation of the temperature effect on the sliding friction and wear properties of the bulk metallic glass (BMG). To improve the friction and wear properties of the BMG, the disk specimens were developed in the alloy system of Fe67.6C7.1Si3.3B5.5P8.7Cr2.3Mo2.6Al2Co1.0 using hot metal and industrial ferro-alloys. The friction and wear test was performed using flat-on-flat contact configuration of unidirectional tribometer and Si3N4 ce...

  1. Electronic and Optical Properties of Titanium Nitride Bulk and Surfaces from First Principles Calculations (Postprint)

    2015-11-18

    properties of TiN bulk and surface structures were previously per- formed,24–35 analysis of the optical properties at an ab initio level for this...TDDFT dielectric functions has shown that the functional is subject to validation with GW-BSE calcula- tions. Analysis of the GW0-BSE results in...al.55) is given by the Cartesian tensor eð2Þab ðxÞ ¼ 4p 2e2 X limq!0 1 q2 P c;v;k2wkdðwkck vk wÞ huckþeaqjuvkihuckþeabqjuvki, where x is in

  2. Polymerization Behavior and Mechanical Properties of High-Viscosity Bulk Fill and Low Shrinkage Resin Composites.

    Shibasaki, S; Takamizawa, T; Nojiri, K; Imai, A; Tsujimoto, A; Endo, H; Suzuki, S; Suda, S; Barkmeier, W W; Latta, M A; Miyazaki, M

    The present study determined the mechanical properties and volumetric polymerization shrinkage of different categories of resin composite. Three high viscosity bulk fill resin composites were tested: Tetric EvoCeram Bulk Fill (TB, Ivoclar Vivadent), Filtek Bulk Fill posterior restorative (FB, 3M ESPE), and Sonic Fill (SF, Kerr Corp). Two low-shrinkage resin composites, Kalore (KL, GC Corp) and Filtek LS Posterior (LS, 3M ESPE), were used. Three conventional resin composites, Herculite Ultra (HU, Kerr Corp), Estelite ∑ Quick (EQ, Tokuyama Dental), and Filtek Supreme Ultra (SU, 3M ESPE), were used as comparison materials. Following ISO Specification 4049, six specimens for each resin composite were used to determine flexural strength, elastic modulus, and resilience. Volumetric polymerization shrinkage was determined using a water-filled dilatometer. Data were evaluated using analysis of variance followed by Tukey's honestly significant difference test (α=0.05). The flexural strength of the resin composites ranged from 115.4 to 148.1 MPa, the elastic modulus ranged from 5.6 to 13.4 GPa, and the resilience ranged from 0.70 to 1.0 MJ/m 3 . There were significant differences in flexural properties between the materials but no clear outliers. Volumetric changes as a function of time over a duration of 180 seconds depended on the type of resin composite. However, for all the resin composites, apart from LS, volumetric shrinkage began soon after the start of light irradiation, and a rapid decrease in volume during light irradiation followed by a slower decrease was observed. The low shrinkage resin composites KL and LS showed significantly lower volumetric shrinkage than the other tested materials at the measuring point of 180 seconds. In contrast, the three bulk fill resin composites showed higher volumetric change than the other resin composites. The findings from this study provide clinicians with valuable information regarding the mechanical properties and

  3. Determining the properties of dense matter: Superconductivity, bulk viscosity, and light reflection in compact stars

    Good, Gerald J.

    In this dissertation, we investigate the properties of matter, denser than nuclei, that exists inside compact stars. First, we examine a mixed superfluid/superconductor system, which likely occurs in neutron star cores. We derive an effective theory of Cooper pair quasiparticles from a microscopic theory of nucleons, and calculate the coupling strengths between quasiparticles. We then calculate the structure of magnetic flux tubes, taking into consideration interactions between neutron and proton Cooper pairs. We find that interactions between the condensates can lead to interesting phenomena and new phases at the border between type-I and type-II behavior. Next, we examine the response of nuclear matter to vibrational modes by calculating the bulk viscosity from purely leptonic processes. We find that for hot neutron stars, the bulk viscosity due to leptons is very small compared to the bulk viscosity due to nucleons, but for cold neutron stars, the leptonic component is dominant. Finally, we derive the reflection and transmission properties of light at boundaries between phases of matter that have two independent U(1) generators, which may exist at the surface of "strange stars" or at boundaries between different phases of matter in a neutron star.

  4. Composition design and mechanical properties of ternary Cu–Zr–Ti bulk metallic glasses

    Pan, Ye; Zeng, Yuqiao; Jing, Lijun; Zhang, Lu; Pi, Jinhong

    2014-01-01

    Highlights: • Newly designed monolithic bulk metallic glasses are of good glass-forming ability. • Cu 50 Zr 44 Ti 6 exhibits excellent plastic deformation up to ∼7.4%. • Copious and intersected shear bans are observed in the fractography of Cu 50 Zr 44 Ti 6 . • Cu 50 Zr 44 Ti 6 has the best plasticity in the ternary Cu–Zr–Ti bulk metallic glasses. - Abstract: The new compositions of ternary Cu–Zr–Ti bulk metallic glasses are predicted by integrating calculation of vacancy formation energy, mixing enthalpy and configuration entropy of the alloys based on thermodynamics of glass formers. The monolithic amorphous rods of 3 mm diameter have been successfully fabricated, and characterized by X-ray diffractometry, differential scanning calorimetry, scanning electronic microscopy, transmission electronic microscopy and compression tests. The results show that the designed alloys possess good glass forming ability and excellent mechanical properties. The mechanical properties of the samples can be effectively improved by regulating their composition. The monolithic amorphous rod of Cu 50 Zr 44 Ti 6 exhibits a high fracture strength of 1855 MPa and excellent plastic deformation up to ∼7.4%. The formation and propagation of shear bands in samples are also investigated. The enhancement of plastic deformation is mainly contributed to multiplication and intersection of shear bands

  5. Bulk and Thin film Properties of Nanoparticle-based Ionic Materials

    Fang, Jason

    2008-03-01

    Nanoparticle-based ionic materials (NIMS) offer exciting opportunities for research at the forefront of science and engineering. NIMS are hybrid particles comprised of a charged oligomeric corona attached to hard, inorganic nanoparticle cores. Because of their hybrid nature, physical properties --rheological, optical, electrical, thermal - of NIMS can be tailored over an unusually wide range by varying geometric and chemical characteristics of the core and canopy and thermodynamic variables such as temperature and volume fraction. On one end of the spectrum are materials with a high core content, which display properties similar to crystalline solids, stiff waxes, and gels. At the opposite extreme are systems that spontaneously form particle-based fluids characterized by transport properties remarkably similar to simple liquids. In this poster I will present our efforts to synthesize NIMS and discuss their bulk and surface properties. In particular I will discuss our work on preparing smart surfaces using NIMS.

  6. Effects of sintering conditions on critical current properties and microstructures of MgB2 bulks

    Yamamoto, Akiyasu; Shimoyama, Jun-ichi; Ueda, Shinya; Katsura, Yukari; Iwayama, Isao; Horii, Shigeru; Kishio, Kohji

    2005-01-01

    The effects of heating conditions on critical current properties and microstructures of undoped MgB 2 bulks were systematically studied. Strong correlation was observed between J c and microstructures. The network structure with an excellent inter-grain connectivity of MgB 2 grains contributed to high-J c under low magnetic fields, and small grain size of MgB 2 enhanced the grain boundary flux pinning. Long time heating at low temperatures below the melting point of magnesium was discovered to be most effective for synthesis of MgB 2 bulks having strongly connected MgB 2 network structure with small grains. The sample heated at 550 deg. C for 1200 h recorded a high-J c of 4.02 x 10 5 A cm -2 at 20 K in self-field, while high-temperature and long time heating brought a significant grain growth which resulted in low J c

  7. Structure and physical properties of silicon clusters and of vacancy clusters in bulk silicon

    Sieck, A.

    2000-01-01

    In this thesis the growth-pattern of free silicon clusters and vacancy clusters in bulk silicon is investigated. The aim is to describe and to better understand the cluster to bulk transition. Silicon structures in between clusters and solids feature new interesting physical properties. The structure and physical properties of silicon clusters can be revealed by a combination of theory and experiment, only. Low-energy clusters are determined with different optimization techniques and a density-functional based tight-binding method. Additionally, infrared and Raman spectra, and polarizabilities calculated within self-consistent field density-functional theory are provided for the smaller clusters. For clusters with 25 to 35 atoms an analysis of the shape of the clusters and the related mobilities in a buffer gas is given. Finally, the clusters observed in low-temperature experiments are identified via the best match between calculated properties and experimental data. Silicon clusters with 10 to 15 atoms have a tricapped trigonal prism as a common subunit. Clusters with up to about 25 atoms follow a prolate growth-path. In the range from 24 to 30 atoms the geometry of the clusters undergoes a transition towards compact spherical structures. Low-energy clusters with up to 240 atoms feature a bonding pattern strikingly different from the tetrahedral bonding in the solid. It follows that structures with dimensions of several Angstroem have electrical and optical properties different from the solid. The calculated stabilities and positron-lifetimes of vacancy clusters in bulk silicon indicate the positron-lifetimes of about 435 ps detected in irradiated silicon to be related to clusters of 9 or 10 vacancies. The vacancies in these clusters form neighboring hexa-rings and, therefore, minimize the number of dangling bonds. (orig.)

  8. Using molecular mechanics to predict bulk material properties of fibronectin fibers.

    Mark J Bradshaw

    Full Text Available The structural proteins of the extracellular matrix (ECM form fibers with finely tuned mechanical properties matched to the time scales of cell traction forces. Several proteins such as fibronectin (Fn and fibrin undergo molecular conformational changes that extend the proteins and are believed to be a major contributor to the extensibility of bulk fibers. The dynamics of these conformational changes have been thoroughly explored since the advent of single molecule force spectroscopy and molecular dynamics simulations but remarkably, these data have not been rigorously applied to the understanding of the time dependent mechanics of bulk ECM fibers. Using measurements of protein density within fibers, we have examined the influence of dynamic molecular conformational changes and the intermolecular arrangement of Fn within fibers on the bulk mechanical properties of Fn fibers. Fibers were simulated as molecular strands with architectures that promote either equal or disparate molecular loading under conditions of constant extension rate. Measurements of protein concentration within micron scale fibers using deep ultraviolet transmission microscopy allowed the simulations to be scaled appropriately for comparison to in vitro measurements of fiber mechanics as well as providing estimates of fiber porosity and water content, suggesting Fn fibers are approximately 75% solute. Comparing the properties predicted by single molecule measurements to in vitro measurements of Fn fibers showed that domain unfolding is sufficient to predict the high extensibility and nonlinear stiffness of Fn fibers with surprising accuracy, with disparately loaded fibers providing the best fit to experiment. This work shows the promise of this microstructural modeling approach for understanding Fn fiber properties, which is generally applicable to other ECM fibers, and could be further expanded to tissue scale by incorporating these simulated fibers into three dimensional

  9. Structure and properties of bulk amorphous magnetically soft coatings prepared by plasma spraying

    Kalita, V.I.; Kekalo, I.B.; Komlev, D.I.; Taranichev, V.E.

    1995-01-01

    Co-Ni-Fe-Si-B composition plasma coatings consisting of amorphous disk-shaped particles forming the bulk of a coating, of crystalline particles and of a threshold space, were studied. Iron and metalloid distribution heterogeneous by the thickness represents a peculiar feature for coating amorphous particles. Structure of coatings and their magnetic properties depend on some technological parameters. Conclusion is made that at annealing the variation of magnetic properties is determined by the processes of directed ordering and stratification of amorphous phase, while the low level of the initial magnetic properties of coatings is caused alongside with structure peculiarities, by occurrence of independent fine-dispersive domain structure in each disk-shaped amorphous phase. 14 refs., 8 figs., 6 tabs

  10. Temperature dependence of the bulk and surface properties of liquid Zn-Cd alloys

    Awe, O.E. [University of Ibadan, Department of Physics, Ibadan (Nigeria); Azeez, A.A. [African University of Science and Technology, Abuja (Nigeria)

    2017-05-15

    The effects of temperature on the bulk and surface properties of liquid Zn-Cd alloys have been theoretically investigated, using a combination of self association model, Darken's thermodynamic equation for diffusion, empirical model for viscosity and a statistical mechanics model. The results from this study show that change in temperature resulted in cross-over effects in bulk and surface properties. We also found that with an increase in temperature, a pronounced asymmetry of viscosity isotherm is significantly reduced, and viscosity isotherm exhibited anomalous behaviour. Our results reveal that the homocoordination tendency in Zn-Cd liquid alloys is not strong and reduces with increasing temperature. The study further suggests a pronounced segregation of Cd-atoms at the surface of Zn-Cd liquid alloys and the extent of segregation reduces with temperature. We as well found that, in addition to the reported understanding that size-factor determines the compositional location of asymmetry of the viscosity isotherm, temperature is an operating parameter that has effect, not only on the composition of asymmetry, but also on the magnitude of asymmetry. In all the properties investigated, the most pronounced effect of temperature (52.9 %) is on the viscosity while the least effect (7.1 %) is on the surface tension. (orig.)

  11. Electronic and structural properties of TiB2: Bulk, surface, and nanoscale effects

    Volonakis, George; Tsetseris, Leonidas; Logothetidis, Stergios

    2011-01-01

    Titanium diboride (TiB 2 ), is a widely used hard material that comprises graphene-like layers of B and intercalated Ti atoms. Here we report the results of extensive first-principles calculations on key properties of bulk TiB 2 , TiB 2 surfaces, and TiB 2 nanocrystals (NCs). The computational approach is first validated based on the agreement between calculated structural and electronic properties of bulk TiB 2 and available experimental and theoretical data. We then obtain the formation energies for several surface cuts and use these values to construct TiB 2 NCs based on the Wulff theorem. Finally, we demonstrate by studying the adsorption of small molecules that hydrogen and oxygen adatoms can be attached through strongly exothermic chemisorption reactions on TiB 2 surfaces. Likewise, water molecules bind on various TiB 2 surfaces and NC facets, with an energetic preference for the latter. The results are relevant to applications that depend on reactivity-related TiB 2 properties, for example resistance to corrosion and interactions with water-based solutions.

  12. Sintering Process and Mechanical Property of MWCNTs/HDPE Bulk Composite.

    Ming-Wen, Wang; Tze-Chi, Hsu; Jie-Ren, Zheng

    2009-08-01

    Studies have proved that increasing polymer matrices by carbon nanotubes to form structural reinforcement and electrical conductivity have significantly improved mechanical and electrical properties at very low carbon nanotubes loading. In other words, increasing polymer matrices by carbon nanotubes to form structural reinforcement can reduce friction coefficient and enhance anti-wear property. However, producing traditional MWCNTs in polymeric materix is an extremely complicated process. Using melt-mixing process or in situ polymerization leads to better dispersion effect on composite materials. In this study, therefore, to simplify MWCNTs /HDPE composite process and increase dispersion, powder was used directly to replace pellet to mix and sinter with MWCNTs. The composite bulks with 0, 0.5, 1, 2 and 4% nanotube content by weight was analyzed under SEM to observe nanotubes dispersion. At this rate, a MWCNTs/HDPE composite bulk with uniformly dispersed MWCNTs was achieved, and through the wear bench (Pin-on-Disk), the wear experiment has accomplished. Accordingly, the result suggests the sintered MWCNTs/HDPE composites amplify the hardness and wear-resist property.

  13. Formation and properties of two-phase bulk metallic glasses by spark plasma sintering

    Xie Guoqiang, E-mail: xiegq@imr.tohoku.ac.jp [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Louzguine-Luzgin, D.V. [WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Inoue, Akihisa [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan)

    2011-06-15

    Research highlights: > Two-phase bulk metallic glasses with high strength and good soft magnetic properties as well as satisfying large-size requirements were produced by spark plasma sintering. > Effects of sintering temperature on thermal stability, microstructure, mechanical and magnetic properties were investigated. > Densified samples were obtained by the spark plasma sintering at above 773 K. - Abstract: Using a mixture of the gas-atomized Ni{sub 52.5}Nb{sub 10}Zr{sub 15}Ti{sub 15}Pt{sub 7.5} and Fe{sub 73}Si{sub 7}B{sub 17}Nb{sub 3} glassy alloy powders, we produced the two-phase bulk metallic glass (BMG) with high strength and good soft magnetic properties as well as satisfying large-size requirements by the spark plasma sintering (SPS) process. Two kinds of glassy particulates were homogeneously dispersed each other. With an increase in sintering temperature, density of the produced samples increased, and densified samples were obtained by the SPS process at above 773 K. Good bonding state among the Ni- and Fe-based glassy particulates was achieved.

  14. Preparation and magnetic properties of anisotropic bulk MnBi/NdFeB hybrid magnets

    Ma, Y. L.; Liu, X. B.; Nguyen, V. V.; Poudyal, N.; Yue, M.; Liu, J. P.

    2016-08-01

    Anisotropic hybrid bulk magnets of MnBi/NdFeB with different composition ratio have been prepared with starting MnBi and Nd2Fe14B powders as well as epoxy resin as a binder in case it is needed to form bulk samples. It has been found that the ratio between the two phases in content has a remarkable influence on the magnetic properties, the thermal stability and the density of the bulk magnets. With increasing MnBi content the binder addition can be reduced. When the MnBi content is larger than 30 wt%, no binder is needed. On the other hand, the coercivity and saturation magnetization were increased significantly with increasing NdFeB content. When the NdFeB content was increased from 0% to 50%, the maximum energy product was enhanced from 4.7 to 10.0 MGOe, respectively. The energy product then decreased gradually with the NdFeB content due to the reduced density of the hybrid magnet. The thermal stability measurements showed that the temperature coefficient of coercivity grew with the MnBi content and became positive with MnBi=80 wt%.

  15. Unique Optical Properties of Methylammonium Lead Iodide Nanocrystals Below the Bulk Tetragonal-Orthorhombic Phase Transition.

    Diroll, Benjamin T; Guo, Peijun; Schaller, Richard D

    2018-02-14

    Methylammonium (MA) and formamidinium (FA) lead halides are widely studied for their potential as low-cost, high-performance optoelectronic materials. Here, we present measurements of visible and IR absorption, steady state, and time-resolved photoluminescence from 300 K to cryogenic temperatures. Whereas FAPbI 3 nanocrystals (NCs) are found to behave in a very similar manner to reported bulk behavior, colloidal nanocrystals of MAPbI 3 show a departure from the low-temperature optical behavior of the bulk material. Using photoluminescence, visible, and infrared absorption measurements, we demonstrate that unlike single crystals and polycrystalline films NCs of MAPbI 3 do not undergo optical changes associated with the bulk tetragonal-to-orthorhombic phase transition, which occurs near 160 K. We find no evidence of frozen organic cation rotation to as low as 80 K or altered exciton binding energy to as low as 3 K in MAPbI 3 NCs. Similar results are obtained in MAPbI 3 NCs ranging from 20 to over 100 nm and in morphologies including cubes and plates. Colloidal MAPbI 3 NCs therefore offer a window into the properties of the solar-relevant, room-temperature phase of MAPbI 3 at temperatures inaccessible with single crystals or polycrystalline samples. Exploiting this phenomenon, these measurements reveal the existence of an optically passive photoexcited state close to the band edge and persistent slow Auger recombination at low temperature.

  16. Planar versus bulk heterojunction perovskite microstructures: Impact of morphology on photovoltaic properties and recombination dynamics

    Singh, Ranbir; Shukla, Vivek Kumar

    2018-05-01

    In this work, we compare the planar and bulk heterojunction (BHJ) perovskite thin films for their morphologies, photovoltaic properties, and recombination dynamics. The BHJ perovskite thin films were prepared with the addition of fullerene derivative [6, 6]-Phenyl-C60 butyric acid methyl ester (PC60BM). The addition of PC60BM in perovskite provides a pinhole free film with high absorption coefficient and better charge transfer. The solar cells fabricated with BHJ perovskite exhibits power conversion efficiency (PCE) of 13.5%, with remarkably increased short-circuit current density (JSC) of 20.1 mAcm-2 and reduced recombination rate.

  17. Levitation properties of superconducting magnetic bearings using superconducting coils and bulk superconductors

    Arai, Yuuki; Seino, Hiroshi; Nagashima, Ken [Railway Technical Research Institute, 2-8-38 Hikari-cho, Kokubunji-shi, Tokyo 185-8540 (Japan)

    2010-11-15

    We have been developing a flywheel energy storage system (FESS) with 36 MJ energy capacity for a railway system with superconducting magnetic bearings (SMBs). We prepared two kinds of models using superconducting coils and bulk superconductors (SCs). One model demonstrated SMB load capacity of 20 kN and the other model proved non-contact stable levitation and non-contact rotation with SMBs. Combining these results, the feasibility of a 36 MJ energy capacity FESS with SMBs completely inside a cryostat has been confirmed. In this paper, we report the levitation properties of SMBs in these models.

  18. Levitation properties of superconducting magnetic bearings using superconducting coils and bulk superconductors

    Arai, Yuuki; Seino, Hiroshi; Nagashima, Ken

    2010-01-01

    We have been developing a flywheel energy storage system (FESS) with 36 MJ energy capacity for a railway system with superconducting magnetic bearings (SMBs). We prepared two kinds of models using superconducting coils and bulk superconductors (SCs). One model demonstrated SMB load capacity of 20 kN and the other model proved non-contact stable levitation and non-contact rotation with SMBs. Combining these results, the feasibility of a 36 MJ energy capacity FESS with SMBs completely inside a cryostat has been confirmed. In this paper, we report the levitation properties of SMBs in these models.

  19. Fission fragment simulation of fusion neutron radiation effects on bulk mechanical properties

    Van Konynenburg, R.A.; Mitchell, J.B.; Guinan, M.W.; Stuart, R.N.; Borg, R.J.

    1976-01-01

    This research demonstrates the feasibility of using homogeneously-generated fission fragments to simulate high-fluence fusion neutron damage in niobium tensile specimens. This technique makes it possible to measure radiation effects on bulk mechanical properties at high damage states, using conveniently short irradiation times. The primary knock-on spectrum for a fusion reactor is very similar to that produced by fission fragments, and nearly the same ratio of gas atoms to displaced atoms is produced in niobium. The damage from fission fragments is compared to that from fusion neutrons and fission reactor neutrons in terms of experimentally measured yield strength increase, transmission electron microscopy (TEM) observations, and calculated damage energies

  20. Nuclear matter with a pseudo-particle model: static bulk and surface properties

    Idier, D.; Benhassine, B.; Farine, M.; Remaud, B.; Sebille, F.

    1993-01-01

    Direct calculations of cold and hot nuclear matter (bulk and surface properties) are carried out within the frame of a pseudo-particle model using a gaussian decomposition of the distribution function. Comparisons with Hartree-Fock calculations, for a large class of effective interactions, show that such a model is reliable to reproduce accurately the equation of state of nuclear matter for large ranges of densities and temperatures. The number of gaussians per nucleon and the gaussian widths are critical parameters in that semi-classical model. (orig.)

  1. Nuclear matter with pseudo-particle model: static bulk and surface properties

    Idier, D.; Benhassine, B.; Farine, M.; Remaud, B.; Sebille, F.

    1993-12-31

    Direct calculations of cold and hot nuclear matter (bulk and surface properties) are carried out within the frame of a pseudo-particle model using a Gaussian decomposition of the distribution function. Comparisons with Hartree-Fock calculations, for a large class of effective interactions, show that such a model is reliable to reproduce accurately the equation of state of nuclear matter for large ranges of densities and temperatures. The number of Gaussian per nucleon and the Gaussian widths are critical parameters in that semi-classical model. (author) 13 refs.; 9 figs.; 2 tabs.

  2. Nuclear matter with pseudo-particle model: static bulk and surface properties

    Idier, D.; Benhassine, B.; Farine, M.; Remaud, B.; Sebille, F.

    1993-01-01

    Direct calculations of cold and hot nuclear matter (bulk and surface properties) are carried out within the frame of a pseudo-particle model using a Gaussian decomposition of the distribution function. Comparisons with Hartree-Fock calculations, for a large class of effective interactions, show that such a model is reliable to reproduce accurately the equation of state of nuclear matter for large ranges of densities and temperatures. The number of Gaussian per nucleon and the Gaussian widths are critical parameters in that semi-classical model. (author) 13 refs.; 9 figs.; 2 tabs

  3. Nuclear matter with a pseudo-particle model: static bulk and surface properties

    Idier, D. (Lab. de Physique Nucleaire CNRS/IN2P3, Univ. de Nantes (France)); Benhassine, B. (Lab. de Physique Nucleaire CNRS/IN2P3, Univ. de Nantes (France)); Farine, M. (Lab. de Physique Nucleaire CNRS/IN2P3, Univ. de Nantes (France)); Remaud, B. (Lab. de Physique Nucleaire CNRS/IN2P3, Univ. de Nantes (France)); Sebille, F. (Lab. de Physique Nucleaire CNRS/IN2P3, Univ. de Nantes (France))

    1993-11-15

    Direct calculations of cold and hot nuclear matter (bulk and surface properties) are carried out within the frame of a pseudo-particle model using a gaussian decomposition of the distribution function. Comparisons with Hartree-Fock calculations, for a large class of effective interactions, show that such a model is reliable to reproduce accurately the equation of state of nuclear matter for large ranges of densities and temperatures. The number of gaussians per nucleon and the gaussian widths are critical parameters in that semi-classical model. (orig.)

  4. The influence of micropore size on the mechanical properties of bulk hydroxyapatite and hydroxyapatite scaffolds.

    Cordell, Jacqueline M; Vogl, Michelle L; Wagoner Johnson, Amy J

    2009-10-01

    While recognized as a promising bone substitute material, hydroxyapatite (HA) has had limited use in clinical settings because of its inherent brittle behavior. It is well established that macropores ( approximately 100 microm) in a HA implant, or scaffold, are required for bone ingrowth, but recent research has shown that ingrowth is enhanced when scaffolds also contain microporosity. HA is sensitive to synthesis and processing parameters and therefore characterization for specific applications is necessary for transition to the clinic. To that end, the mechanical behavior of bulk microporous HA and HA scaffolds with multi-scale porosity (macropores between rods in the range of 250-350 microm and micropores within the rods with average size of either 5.96 microm or 16.2 microm) was investigated in order to determine how strength and reliability were affected by micropore size (5.96 microm versus 16.2 microm). For the bulk microporous HA, strength increased with decreasing micropore size in both bending (19 MPa to 22 MPa) and compression (71 MPa to 110 MPa). To determine strength reliability, the Weibull moduli for the bulk microporous HA were determined. The Weibull moduli for bending increased (became more reliable) with decreasing pore size (7 to 10) while the Weibull moduli for compression decreased (became less reliable) with decreasing pore size (9 to 6). Furthermore, the elastic properties of the bulk microporous HA (elastic modulus of 30 GPa) and the compressive strengths of the HA scaffolds with multi-scale porosity (8 MPa) did not vary with pore size. The mechanisms responsible for the trends observed were discussed.

  5. Characterization of bulk and shear properties of basmati and non-basmati rice flour.

    Jan, Shumaila; Ghoroi, Chinmay; Saxena, Dharmesh Chandra

    2018-01-01

    Flours are often unstable in relation to their flow performance, which is evident when a free-flowing material ceases to flow and the processing, handling, and production parameters depend on the inherent powder characteristics and their bulk behaviour. The present study was conducted to compare the flowability of basmati and non-basmati rice flour affecting bulk handling, which could be related to its particle size, shape and surface roughness (measured by atomic force microscopy) as well as bulk and shear properties, depending upon the processing conditions. Particle size (171.1-171.9 μm) of both samples was not significantly different. However, the flowability of the non-basmati rice flour was significantly affected by its particle shape (circularity 0.487), surface roughness (124.23 nm) and compressibility (25.32%) in comparison to basmati rice flour (circularity 0.653, surface roughness 113.59 nm and compressibility 21.09%), making it more cohesive than basmati rice flour. Also, basic flow energy was significantly higher in non-basmati flour, thus requiring more energy (147.54 mJ) to flow than basmati rice flour (130.15 mJ). Overall, flowability was analysed by applying three different pressures (3, 6 and 9 kPa), among which non-basmati rice flour was found to be less flowable (flow function coefficient (FFC) 2.33 at 9 kPa) in comparison to basmati (FFC 3.35 at 9 kPa), making bulk handling difficult. This study could be useful in designing processing equipment, hoppers and silos for rice flour handling. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  6. Mechanical and thermal properties of bulk ZrB{sub 2}

    Nakamori, Fumihiro [Graduate School of Engineering, Osaka University (Japan); Ohishi, Yuji, E-mail: ohishi@ms.see.eng.osaka-u.ac.jp [Graduate School of Engineering, Osaka University (Japan); Muta, Hiroaki; Kurosaki, Ken [Graduate School of Engineering, Osaka University (Japan); Fukumoto, Ken-ichi [Research Institute of Nuclear Engineering, University of Fukui (Japan); Yamanaka, Shinsuke [Graduate School of Engineering, Osaka University (Japan); Research Institute of Nuclear Engineering, University of Fukui (Japan)

    2015-12-15

    ZrB{sub 2} appears to have formed in the fuel debris at the Fukushima Daiichi nuclear disaster site, through the reaction between Zircaloy cladding materials and the control rod material B{sub 4}C. Since ZrB{sub 2} has a high melting point of 3518 K, the ceramic has been widely studied as a heat-resistant material. Although various studies on the thermochemical and thermophysical properties have been performed for ZrB{sub 2}, significant differences exist in the data, possibly due to impurities or the porosity within the studied samples. In the present study, we have prepared a ZrB{sub 2} bulk sample with 93.1% theoretical density by sintering ZrB{sub 2} powder. On this sample, we have comprehensively examined the thermal and mechanical properties of ZrB{sub 2} by the measurement of specific heat, ultrasonic sound velocities, thermal diffusivity, and thermal expansion. Vickers hardness and fracture toughness were also measured and found to be 13–23 GPa and 1.8–2.8 MPa m{sup 0.5}, respectively. The relationships between these properties were carefully examined in the present study. - Highlights: • A ZrB{sub 2} bulk sample with 93.1% theoretical density was prepared by sintering ZrB{sub 2} powder. • We have evaluated mechanical and thermal properties such as Vickers hardness, fracture toughness and thermal conductivity. • The relationships between these properties were carefully examined.

  7. Thermal, mechanical and permeation properties of gamma-irradiated multilayer food packaging films containing a buried layer of recycled low-density polyethylene

    Chytiri, Stavroula; Goulas, Antonios E.; Riganakos, Kyriakos A.; Kontominas, Michael G.

    2006-01-01

    The effect of gamma radiation (doses 5-60kGy) on the thermal, mechanical and permeation properties, as well as on IR-spectra of experimental five-layer food packaging films were studied. Films contained a middle buried layer of recycled low-density polyethylene (LDPE) comprising 25-50% by weight of the multilayer structure. Representative films containing 100% virgin LDPE as the buried layer were taken as controls. Results showed that the percentage of recycled LDPE in the multilayer structure did not significantly (p<0.05) affect the melting temperature, tensile strength, percent elongation at break, Young's modulus, oxygen, carbon dioxide and water vapour transmission rate values and the IR-spectra of the non-irradiated and irradiated multilayer films. Irradiation (mainly the higher dose of 60kGy) induced certain small, but statistically significant (p<0.05) differences in the mechanical properties of multilayer films (with or without recycled LDPE layer) while no significant differences were observed in the thermal properties and in the gas and water vapour permeability of multilayer films. The above findings are discussed in relation to the good quality of the pre-consumer scrap used in the present study

  8. Properties of membranes to permeation to radon 222. New development for the measurement of radon 222 in water and water-saturated soils

    Labed, V.; Robe, M.C.

    1992-01-01

    Membranes that exclude water but are permeable to radon can extend the range of environments in which many radon detection systems could operate. We have studied the permeation of 222 Rn through membranes separating air and water phases. The permeation coefficients and the activation energy were calculated for various conditions. Potential applications such as in situ detection of radon in water are discussed

  9. Elastic properties of superconducting bulk metallic glasses; Elastische Eigenschaften von supraleitenden massiven metallischen Glaesern

    Hempel, Marius

    2015-07-01

    Within the framework of this thesis the elastic properties of a superconducting bulk metallic glass between 10 mK and 300 K were first investigated. In order to measure the entire temperature range, in particular the low temperature part, new experimental techniques were developed. Using an inductive readout scheme for a double paddle oscillator it was possible to determine the internal friction and the relative change of sound velocity of bulk metallic glasses with high precision. This allowed for a detailed comparison of the data with different models. The analysis focuses on the low temperature regime where the properties of glassy materials are governed by atomic tunneling systems as described by the tunneling model. The influence of conduction electrons in the normal conducting state and quasiparticles in the superconducting state of the glass were accounted for in the theoretical description, resulting in a good agreement over a large temperature range between measured data and prediction of the tunneling model. This allowed for a direct determination of the coupling constant between electrons and tunneling systems. In the vicinity of the transition temperature Tc the data can only be described if a modified distribution function of the tunneling parameters is applied.

  10. Flux pinning properties of impurity doped MgB2 bulks synthesized by diffusion method

    Ueda, Shinya; Shimoyama, Jun-ichi; Yamamoto, Akiyasu; Katsura, Yukari; Iwayama, Isao; Horii, Shigeru; Kishio, Kohji

    2005-01-01

    Doping effects of carbon-containing impurities on the critical current properties and microstructure were systematically studied for highly dense MgB 2 bulks prepared by the diffusion method starting from magnesium and boron which are separately packed in sealed stainless tubes. Obtained samples exhibited improved critical current density, J c , simply by an increase of effective current pass. A non-doped MgB 2 recorded almost double high J c at 20 K compared with those of the conventional porous MgB 2 bulks having ∼50% of the theoretical density, while irreversibility field, H irr , did not largely change. J c under high magnetic fields were enhanced by doping of carbon-containing impurities, such as SiC and B 4 C. Optimal doping levels of SiC and B 4 C for high critical current properties at 20 K are found to be ∼2% and 5%, respectively, as nominal carbon concentration at boron site. Difference in the optimal doping levels is originated from the difference in their reactivity

  11. Study of microstructure and electrical properties of bulk YBCO prepared by melt textured growth technique

    Gonal, M. R.; Krishnan, Madangopal; Tewari, R.; Tyagi, A. K.; Gyore, A.; Vajda, I.

    2015-01-01

    Bulk YBCO components were prepared using Melt Texture Growth (MTG) technique. Components were fabricated using MTG by addition of Y 2 BaCuO 5 (Y211) and Ag to YBCO, which leads to improved grain size without affecting superconducting properties. Green compacts prepared by cold isostatic pressing were pre-sintered at 930°C before subjecting melt texturing. Cooling rates lower than 1 °C.h −1 was used, in between (peritectic) temperature of about 995 and 1025°C, to obtain large grained components. Microstructure studies in details were carried out by Scanning Electron Microscope (SEM), Electron Probe Micro Analysis (EPMA), Orientation Imaging Microscope (OIM) and TEM correlated with electrical properties like Critical current density (J c )

  12. The structural relaxation effect on the nanomechanical properties of a Ti-based bulk metallic glass

    Huang, Yongjiang, E-mail: yjhuang@hit.edu.cn [State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001 (China); School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Key Laboratory of Micro-Systems and Micro-Structures Manufacturing, Harbin Institute of Technology, Ministry of Education, Harbin 150001 (China); Zhou, Binjun [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Chiu, YuLung, E-mail: y.chiu@bham.ac.uk [School of Metallurgy and Materials, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Fan, Hongbo [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wang, Dongjun [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Key Laboratory of Micro-Systems and Micro-Structures Manufacturing, Harbin Institute of Technology, Ministry of Education, Harbin 150001 (China); Sun, Jianfei; Shen, Jun [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2014-09-01

    Highlights: • The effect of structural relaxation on the nano-mechanical behaviors of BMGs is studied. • The indent load at first pop-in event, the hardness and Young’s modulus are enhanced after annealing. • The differences in nanomechanical properties can be attributed to their different atomic structure. - Abstract: Indentation experiments were performed on the as-cast and the annealed Ti-based bulk metallic glass samples to investigate the effect of structural relaxation on the nanomechanical behaviors of the material. The onset of pop-in event, Young’s modulus, and hardness were found to be sensitive to the structural relaxation of the testing material. The difference in nanomechanical properties between the as-cast and annealed BMG samples is interpreted in terms of free volume theory.

  13. Multifragmentation of a very heavy nuclear system (II): bulk properties and spinodal decomposition

    Frankland, J.D.; Rivet, M.F.; Borderie, B. [Paris-11 Univ., Inst. de Physique Nucleaire, 91 - Orsay (France)] [and others

    2000-07-01

    The properties of fragments and light charged particles emitted in multifragmentation of single sources formed in central 36 A.MeV Gd+U collisions are reviewed. Most of the products are isotropically distributed in the reaction c.m. Fragment kinetic energies reveal the onset of radial collective energy. A bulk effect is experimentally evidenced from the similarity of the charge distribution with that from the lighter 32 A.MeV Xe+Sn system. Spinodal decomposition of finite nuclear matter exhibits the same property in simulated central collisions for the two systems, and appears therefore as a possible mechanism at the origin of multifragmentation in this incident energy domain. (authors)

  14. The structural relaxation effect on the nanomechanical properties of a Ti-based bulk metallic glass

    Huang, Yongjiang; Zhou, Binjun; Chiu, YuLung; Fan, Hongbo; Wang, Dongjun; Sun, Jianfei; Shen, Jun

    2014-01-01

    Highlights: • The effect of structural relaxation on the nano-mechanical behaviors of BMGs is studied. • The indent load at first pop-in event, the hardness and Young’s modulus are enhanced after annealing. • The differences in nanomechanical properties can be attributed to their different atomic structure. - Abstract: Indentation experiments were performed on the as-cast and the annealed Ti-based bulk metallic glass samples to investigate the effect of structural relaxation on the nanomechanical behaviors of the material. The onset of pop-in event, Young’s modulus, and hardness were found to be sensitive to the structural relaxation of the testing material. The difference in nanomechanical properties between the as-cast and annealed BMG samples is interpreted in terms of free volume theory

  15. Multifragmentation of a very heavy nuclear system (II): bulk properties and spinodal decomposition

    Frankland, J.D.; Rivet, M.F.; Borderie, B.

    2000-01-01

    The properties of fragments and light charged particles emitted in multifragmentation of single sources formed in central 36 A.MeV Gd+U collisions are reviewed. Most of the products are isotropically distributed in the reaction c.m. Fragment kinetic energies reveal the onset of radial collective energy. A bulk effect is experimentally evidenced from the similarity of the charge distribution with that from the lighter 32 A.MeV Xe+Sn system. Spinodal decomposition of finite nuclear matter exhibits the same property in simulated central collisions for the two systems, and appears therefore as a possible mechanism at the origin of multifragmentation in this incident energy domain. (authors)

  16. Transport properties of high-temperature superconductors: Surface vs bulk effect

    Burlachkov, L.; Koshelev, A.E.; Vinokur, V.M.

    1996-01-01

    We investigate surface-related transport properties of high-temperature superconductors. We find the mean vortex velocity under applied transport current determined by the activation energies for vortex penetration and exit through the Bean-Livingston barrier. We determine the current distribution between the surfaces of superconductor and the field and current dependencies of the transport activation energies. For a three-dimensional superconductor the transport activation energy, U s 3D , is found to decrease with the external field, H, and transport current, J, as U s 3D ∝H -1/2 and U s 3D ∝J -1/2 , respectively. In the quasi-two-dimensional compounds, U s 2D decays logarithmically with field and current. The interplay between the surface and the bulk contributions to the transport properties, such as current-voltage characteristics, is discussed. copyright 1996 The American Physical Society

  17. Irradiating of Bulk Soybeans: Influence on Their Functional and Sensory Properties for Soyfood Processing

    Chia, Chiew-Ling; Wilson, Lester A.; Boylston, Terri; Perchonok, Michele; French, Stephen

    2006-01-01

    Soybeans were chosen for lunar and planetary missions, where soybeans will be supplied in bulk or grown locally, due to their nutritive value and ability to produce oil and protein for further food applications. However, soybeans must be processed into foods prior to consumption. Radiation that soybeans would be exposed to during bulk storage prior to and during a Mars mission may influence their germination and functional properties. The influence of radiation includes the affect of surface pasteurization to ensure the astronauts safety from food-borne illnesses (HACCP, CCP), and the affect of the amount of radiation the soybeans receive during a Mars mission. Decreases in the amount of natural antioxidants free radical formation, and oxidation-induced changes in the soybean will influence the nutritional value, texture, color, and aroma of soyfoods. The objective of this study was to determine the influence of pasteurization and sterilization surface radiation on whole soybeans using gamma and electron beam radiation. The influence of 0, 1, 5, 10, and 30kGy on microbial load, germination rate, ease of processing, and quality of soymilk and tofu were determined. Surface radiation of whole dry soybeans using electron beam or gamma rays from 1-30kGy did provide microbial safety for the astronauts. However, the lower dose levels had surviving yeasts and molds. These doses caused oxidative changes that resulted in soymilk and tofu with rancid aromas. GC-MS of the aroma compounds using SPME Headspace confirmed the presence of lipid oxidation compounds. Soybean germination ability was reduced as radiation dosage increased. While lower doses may reduce these problems, the ability to insure microbial safety of bulk soybeans will be lost. Counter measures could include vacuum packaging, nitrogen flushing, added antioxidants, and radiating under freezing conditions. Doses below 1kGy need to be investigated further to determine the influence of the radiation encountered

  18. First principles study of optical properties of molybdenum disulfide: From bulk to monolayer

    Hieu, Nguyen N.; Ilyasov, Victor V.; Vu, Tuan V.; Poklonski, Nikolai A.; Phuc, Huynh V.; Phuong, Le T. T.; Hoi, Bui D.; Nguyen, Chuong V.

    2018-03-01

    In this paper, we theoretically study the optical properties of both bulk and monolayer MoS2 using first-principles calculations. The optical characters such as: dielectric function, optical reflectivity, and electron energy-loss spectrum of MoS2 are observed in the energy region from 0 to 15 eV. At equilibrium state the dielectric constant in the parallel E∥ x and perpendicular E∥ z directions are of 15.01 and 8.92 for bulk while they are 4.95 and 2.92 for monolayer MoS2, respectively. In the case of bulk MoS2, the obtained computational results for both real and imaginary parts of the dielectric constant are in good agreement with the previous experimental data. In the energy range from 0 to 6 eV, the dielectric functions have highly anisotropic, whereas they become isotropic when the energy is larger than 7 eV. For the adsorption spectra and optical reflectivity, both the collective plasmon resonance and (π + σ) electron plasmon peaks are observed, in which the transition in E∥ x direction is accordant with the experiment data more than the transition in E∥ z direction is. The refractive index, extinction index, and electron energy-loss spectrum are also investigated. The observed prominent peak at 23.1 eV in the energy-loss spectra is in good agreement with experiment value. Our results may provide a useful potential application for the MoS2 structures in electronic and optoelectronic devices.

  19. Channeling Polyolefin Molecular Structure - Bulk Property Correlation Strategies for Industrial Applicability

    Hule, Rohan; Thurman, Derek; Doufas, Antonios

    Polyolefins occupy a significant volume of the polymer products portfolio in commodity and high value applications. Quantifying and optimizing structure-property relationships enables growth in new markets. It is well recognized that coupling lab-based, comprehensive methodologies with bulk properties of interest to industrial environments offer the greatest potential of technology advancement, ultimately leading to commercial success. It is imperative to recognize the existing gap of knowledge translation between lab measurements and industrial-scale operability. This study highlights experimental HDPEs synthesized from dual, single-site, co-supported catalysts that exhibit enhanced solid-state properties such as stiffness, impact and ESCR surpassing conventional trends. Commercial resins across distinct sub-families were included as well. Commonality amongst these resins is bimodality and broad MW distribution with well-defined splits and spreads. Investigations on commercially relevant parameters such as melt strength, melt elasticity and shear thinning established excellent performance for experimental bimodals, corroborating potential benefits compared to commercial HDPEs. To summarize, the effort highlights well-recognized pathways such as improvements in mechanical and melt properties that can be attributed to apposite tuning of polymer chain architecture and MW distribution with implications across myriad markets. Ultimately, this may serve as a pathway for producing innovative products that deliver business success and growth.

  20. A study of preparation techniques and properties of bulk nanocomposites based on aqueous albumin dispersion

    Gerasimenko, A. Yu.; Dedkova, A. A.; Ichkitidze, L. P.; Podgaetskii, V. M.; Selishchev, S. V.

    2013-08-01

    Bulk nanocomposites prepared from an aqueous albumin dispersion with carbon nanotubes by removing the liquid component from the dispersion have been investigated. The composites were obtained by thermostating and exposure to LED and IR diode laser radiation. The nanocomposites obtained under laser irradiation retain their shape and properties for several years, in contrast to the composites fabricated in different ways (which decompose into small fragments immediately after preparation). The low density of the composites under study (˜1200 kg/m3), which is close to the density of water, is due to their high porosity. The hardness of stable nanocomposites (˜300 MPa) was found to be at the same level as the hardness of polymethylmethacrylate, aluminum, and iron and close to the hardness of human bone tissue. The cluster quasiordering of the inner structure of nanocomposites revealed by atomic force microscopy indicates the possibility of forming a bulk nanotube framework in them, which can be caused by the effect of the electric field of laser radiation and ensure their stability and hardness. The presence of a framework in nanocomposites provides conditions for self-assembly of biological tissues and makes it possible to apply laser-prepared nanocomposites as a component of surgical implants.

  1. Bulk and surface properties of magnesium peroxide MgO2

    Esch, Tobit R.; Bredow, Thomas

    2016-12-01

    Magnesium peroxide has been identified in Mg/air batteries as an intermediate in the oxygen reduction reaction (ORR) [1]. It is assumed that MgO2 is involved in the solid-electrolyte interphase on the cathode surface. Therefore its structure and stability play a crucial role in the performance of Mg/air batteries. In this work we present a theoretical study of the bulk and low-index surface properties of MgO2. All methods give a good account of the experimental lattice parameters for MgO2 and MgO bulk. The reaction energies, enthalpies and free energies for MgO2 formation from MgO are compared among the different DFT methods and with the local MP2 method. A pronounced dependence from the applied functional is found. At variance with a previous theoretical study but in agreement with recent experiments we find that the MgO2 formation reaction is endothermic (HSE06-D3BJ: ΔH = 51.9 kJ/mol). The stability of low-index surfaces MgO2 (001) (Es = 0.96 J/m2) and (011) (Es = 1.98 J/m2) is calculated and compared to the surface energy of MgO (001). The formation energy of neutral oxygen vacancies in the topmost layer of the MgO2 (001) surface is calculated and compared with defect formation energies for MgO (001).

  2. Ab-initio Computation of the Electronic, transport, and Bulk Properties of Calcium Oxide.

    Mbolle, Augustine; Banjara, Dipendra; Malozovsky, Yuriy; Franklin, Lashounda; Bagayoko, Diola

    We report results from ab-initio, self-consistent, local Density approximation (LDA) calculations of electronic and related properties of calcium oxide (CaO) in the rock salt structure. We employed the Ceperley and Alder LDA potential and the linear combination of atomic orbitals (LCAO) formalism. Our calculations are non-relativistic. We implemented the LCAO formalism following the Bagayoko, Zhao, and Williams (BZW) method, as enhanced by Ekuma and Franklin (BZW-EF). The BZW-EF method involves a methodical search for the optimal basis set that yields the absolute minima of the occupied energies, as required by density functional theory (DFT). Our calculated, indirect band gap of 6.91eV, from towards the L point, is in excellent agreement with experimental value of 6.93-7.7eV, at room temperature (RT). We have also calculated the total (DOS) and partial (pDOS) densities of states as well as the bulk modulus. Our calculated bulk modulus is in excellent agreement with experiment. Work funded in part by the US Department of Energy (DOE), National Nuclear Security Administration (NNSA) (Award No.DE-NA0002630), the National Science Foundation (NSF) (Award No, 1503226), LaSPACE, and LONI-SUBR.

  3. Bioactivity and structural properties of nanostructured bulk composites containing Nb2O5 and natural hydroxyapatite

    Bonadio, T. G. M.; Sato, F.; Medina, A. N.; Weinand, W. R.; Baesso, M. L.; Lima, W. M.

    2013-06-01

    In this work, we investigate the bioactivity and structural properties of nanostructured bulk composites that are composed of Nb2O5 and natural hydroxyapatite (HAp) and are produced by mechanical alloying and powder metallurgy. X-ray diffraction and Raman spectroscopy data showed that the milling process followed by a heat treatment at 1000 °C induced chemical reactions along with the formation of the CaNb2O6, PNb9O25 and Ca3(PO4)2 phases. Rietveld refinement indicated significant changes in each phase weight fraction as a function of HAp concentration. These changes influenced the in vitro bioactivity of the material. XRD and FTIR analyses indicated that the composites exhibited bioactivity characteristics by forming a carbonated apatite layer when the composites were immersed in a simulated body fluid. The formed layers had a maximum thickness of 13 μm, as measured by confocal Raman spectroscopy and as confirmed by scanning electron microscopy. The results of this work suggest that the tested bulk composites are promising biomaterials for use in implants.

  4. Optical properties of single-layer, double-layer, and bulk MoS2

    Molina-Sanchez, Alejandro; Wirtz, Ludger [University of Luxembourg (Luxembourg); Hummer, Kerstin [University of Vienna, Vienna (Austria)

    2013-07-01

    The rise of graphene has brought attention also to other layered materials that can complement graphene or that can be an alternative in applications as transistors. Single-layer MoS{sub 2} has shown interesting electronic and optical properties such as as high electron mobility at room temperature and an optical bandgap of 1.8 eV. This makes the material suitable for transistors or optoelectronic devices. We present a theoretical study of the optical absorption and photoluminescence spectra of single-layer, double-layer and bulk MoS{sub 2}. The excitonic states have been calculated in the framework of the Bethe-Salpeter equation, taking into account the electron-hole interaction via the screened Coulomb potential. In addition to the step-function like behaviour that is typical for the joint-density of states of 2D materials with parabolic band dispersion, we find a bound excitonic peak that is dominating the luminescence spectra. The peak is split due to spin-orbit coupling for the single-layer and split due to layer-layer interaction for few-layer and bulk MoS{sub 2}. We discuss the changes of the optical bandgap and of the exciton binding energy with the number of layers, comparing our results with the reported experimental data.

  5. Thermal stability and magnetocaloric properties of GdDyAlCo bulk metallic glasses

    Liang, L. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Hui, X. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China)], E-mail: huixd01@hotmail.com; Chen, G.L. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China)

    2008-01-25

    Gd{sub 56-x}Dy{sub x}Al{sub 24}Co{sub 20} (x = 16, 20 and 22) bulk metallic glasses (BMGs) alloys with a diameter of 2, 3 and 3 mm, respectively, were prepared by using copper mold casting. These alloys exhibit higher values of the glass transition temperature, crystallization temperature, and activation energy of the glass transition and crystallization, compared with those of other known rare-earth-based BMGs. A maximum magnetic entropy changes of 15.78 J/(kg K) is obtained in Gd{sub 40}Dy{sub 16}Al{sub 24}Co{sub 20}, which is the maximal among all the bulk metallic glasses, and is much larger than those of the known crystalline magnetic refrigerant compound Gd{sub 5}Si{sub 2}Ge{sub 1.9}Fe{sub 0.1} and pure Gd metal. All the three BMG alloys have a broader temperature range of the entropy change peak, resulting in larger refrigerate capacities (RC) than those of conventional crystalline materials. The excellent magnetocaloric properties combining with high thermal stability make them an attractive candidate for magnetic refrigerants in the temperature range of 20-100 K.

  6. Effect of sample thickness on the extracted near-infrared bulk optical properties of Bacillus subtilis in liquid culture.

    Dzhongova, Elitsa; Harwood, Colin R; Thennadil, Suresh N

    2011-11-01

    In order to determine the bulk optical properties of a Bacillus subtilis culture during growth phase we investigated the effect of sample thickness on measurements taken with different measurement configurations, namely total diffuse reflectance and total diffuse transmittance. The bulk optical properties were extracted by inverting the measurements using the radiative transfer theory. While the relationship between reflectance and biomass changes with sample thickness and the intensity (absorbance) levels vary significantly for both reflectance and transmittance measurements, the extracted optical properties show consistent behavior in terms of both the relationship with biomass and magnitude. This observation indicates the potential of bulk optical properties for building models that could be more easily transferable compared to those built using raw measurements.

  7. Microstructural and bulk property changes in hardened cement paste during the first drying process

    Maruyama, Ippei, E-mail: ippei@dali.nuac.nagoya-u.ac.jp [Graduate School of Environmental Studies, Nagoya University, ES Building, No. 546, Furo-cho, Chikusa-ku, Nagoya 464–8603 (Japan); Nishioka, Yukiko; Igarashi, Go [Graduate School of Environmental Studies, Nagoya University, ES Building, No. 539, Furo-cho, Chikusa-ku, Nagoya 464–8603 (Japan); Matsui, Kunio [Products and Marketing Development Dept. Asahi-KASEI Construction Materials Corporation, 106 Someya, Sakai-machi, Sashima-gun, Ibaraki, 306–0493 (Japan)

    2014-04-01

    This paper reports the microstructural changes and resultant bulk physical property changes in hardened cement paste (hcp) during the first desorption process. The microstructural changes and solid-phase changes were evaluated by water vapor sorption, nitrogen sorption, ultrasonic velocity, and {sup 29}Si and {sup 27}Al nuclear magnetic resonance. Strength, Young's modulus, and drying shrinkage were also examined. The first drying process increased the volume of macropores and decreased the volume of mesopores and interlayer spaces. Furthermore, in the first drying process globule clusters were interconnected. During the first desorption, the strength increased for samples cured at 100% to 90% RH, decreased for 90% to 40% RH, and increased again for 40% to 11% RH. This behavior is explained by both microstructural changes in hcp and C–S–H globule densification. The drying shrinkage strains during rapid drying and slow drying were compared and the effects of the microstructural changes and evaporation were separated.

  8. Glass forming ability and mechanical properties of Zr50Cu42Al8 bulk metallic glass

    Xia, L; Chan, K C; Wang, G; Liu, L

    2008-01-01

    In this work, we report that Zr 50 Cu 42 Al 8 bulk metallic glass (BMG) exhibits excellent glass forming ability and mechanical properties. Zr 50 Cu 42 Al 8 glassy rods with a diameter of 3 mm were prepared using conventional copper mould suction casting. The glassy rod exhibits a modulus of about 115 GPa and a fracture strength of about 2 GPa, and, as compared with other large-scale BMGs, it has excellent room-temperature plasticity of up to 20% under compression. The fracture mechanism of the rod was investigated by microstructural investigations, and it was found that the large plasticity of the as-cast rod is closely related to the in situ formation of nano-crystalline particles embedded in the amorphous matrix.

  9. Relationship between critical current properties and microstructure in cylindrical RE123 melt-solidified bulks

    Nakashima, T.; Shimoyama, J.; Honzumi, M.; Tazaki, Y.; Horii, S.; Kishio, K.

    2005-01-01

    We report the synthesis of cylindrical melt-solidified bulks in REBa 2 Cu 3 O y (RE = Sm, Gd, Dy, Ho, Y and Er), and their critical current properties and microstructures of the a- and the c-growth regions. It was found from the microstructure analysis that the volume fractions of RE211 particles in the c-growth region were always lower than those in the a-growth region. Moreover, those in the c-growth region were increased with distance from the seed crystal. Interestingly, the second peak effects in J c -B curves were prominently enhanced for the c-growth region. J c values at zero field for the c-growth region through the appropriate oxygen post-annealing reached approximately 95 kA cm -2 for RE = Ho, Dy and Y

  10. Bulk Fermi surface and electronic properties of Cu0.07Bi2Se3

    Martin, C.; Craciun, V.; Miller, K. H.; Uzakbaiuly, B.; Buvaev, S.; Berger, H.; Hebard, A. F.; Tanner, D. B.

    2013-05-01

    The electronic properties of Cu0.07Bi2Se3 have been investigated using Shubnikov-de Haas and optical reflectance measurements. Quantum oscillations reveal a bulk, three-dimensional Fermi surface with anisotropy kFc/kFab≈ 2 and a modest increase in free-carrier concentration and in scattering rate with respect to the undoped Bi2Se3, also confirmed by reflectivity data. The effective mass is almost identical to that of Bi2Se3. Optical conductivity reveals a strong enhancement of the bound impurity bands with Cu addition, suggesting that a significant number of Cu atoms enter the interstitial sites between Bi and Se layers or may even substitute for Bi. This conclusion is also supported by x-ray diffraction measurements, where a significant increase of microstrain was found in Cu0.07Bi2Se3, compared to Bi2Se3.

  11. Electronic and optical properties of titanium nitride bulk and surfaces from first principles calculations

    Mehmood, Faisal; Pachter, Ruth; Murphy, Neil R.; Johnson, Walter E.

    2015-11-01

    Prediction of the frequency-dependent dielectric function of thin films poses computational challenges, and at the same time experimental characterization by spectroscopic ellipsometry remains difficult to interpret because of changes in stoichiometry and surface morphology, temperature, thickness of the film, or substrate. In this work, we report calculations for titanium nitride (TiN), a promising material for plasmonic applications because of less loss and other practical advantages compared to noble metals. We investigated structural, electronic, and optical properties of stoichiometric bulk TiN, as well as of the TiN(100), TiN(110), and TiN(111) outermost surfaces. Density functional theory (DFT) and many-body GW methods (Green's (G) function-based approximation with screened Coulomb interaction (W)) were used, ranging from G0W0, GW0 to partially self-consistent sc-GW0, as well as the GW-BSE (Bethe-Salpeter equation) and time-dependent DFT (TDDFT) methods for prediction of the optical properties. Structural parameters and the band structure for bulk TiN were shown to be consistent with previous work. Calculated dielectric functions, plasma frequencies, reflectivity, and the electron energy loss spectrum demonstrated consistency with experiment at the GW0-BSE level. Deviations from experimental data are expected due to varying experimental conditions. Comparison of our results to spectroscopic ellipsometry data for realistic nanostructures has shown that although TDDFT may provide a computationally feasible level of theory in evaluation of the dielectric function, application is subject to validation with GW-BSE calculations.

  12. Electronic and optical properties of titanium nitride bulk and surfaces from first principles calculations

    Mehmood, Faisal; Pachter, Ruth; Murphy, Neil R.; Johnson, Walter E.

    2015-01-01

    Prediction of the frequency-dependent dielectric function of thin films poses computational challenges, and at the same time experimental characterization by spectroscopic ellipsometry remains difficult to interpret because of changes in stoichiometry and surface morphology, temperature, thickness of the film, or substrate. In this work, we report calculations for titanium nitride (TiN), a promising material for plasmonic applications because of less loss and other practical advantages compared to noble metals. We investigated structural, electronic, and optical properties of stoichiometric bulk TiN, as well as of the TiN(100), TiN(110), and TiN(111) outermost surfaces. Density functional theory (DFT) and many-body GW methods (Green's (G) function-based approximation with screened Coulomb interaction (W)) were used, ranging from G 0 W 0 , GW 0 to partially self-consistent sc-GW 0 , as well as the GW-BSE (Bethe-Salpeter equation) and time-dependent DFT (TDDFT) methods for prediction of the optical properties. Structural parameters and the band structure for bulk TiN were shown to be consistent with previous work. Calculated dielectric functions, plasma frequencies, reflectivity, and the electron energy loss spectrum demonstrated consistency with experiment at the GW 0 -BSE level. Deviations from experimental data are expected due to varying experimental conditions. Comparison of our results to spectroscopic ellipsometry data for realistic nanostructures has shown that although TDDFT may provide a computationally feasible level of theory in evaluation of the dielectric function, application is subject to validation with GW-BSE calculations

  13. Pressure-Dependent Electronic and Transport Properties of Bulk Platinum Oxide by Density Functional Theory

    Kansara, Shivam; Gupta, Sanjeev K.; Sonvane, Yogesh; Nekrasov, Kirill A.; Kichigina, Natalia V.

    2018-02-01

    The structural, electronic, and vibrational properties of bulk platinum oxide (PtO) at compressive pressures in the interval from 0 GPa to 35 GPa are investigated using the density functional theory. The calculated electronic band structure of PtO shows poor metallicity at very low density of states on the Fermi level. However, the hybrid pseudopotential calculation yielded 0.78 eV and 1.30 eV direct band and indirect gap, respectively. Importantly, our results predict that PtO has a direct band gap within the framework of HSE06, and it prefers equally zero magnetic order at different pressures. In the Raman spectra, peaks are slightly shifted towards higher frequency with the decrease in pressure. We have also calculated the thermoelectric properties, namely the electronic thermal conductivity and electrical conductivity, with respect to temperature and thermodynamic properties such as entropy, specific heat at constant volume, enthalpy and Gibbs free energy with respect to pressure. The result shows that PtO is a promising candidate for use as a catalyst, in sensors, as a photo-cathode in water electrolysis, for thermal decomposition of inorganic salt and fuel cells.

  14. Theoretical study of turbulent channel flow - Bulk properties, pressure fluctuations, and propagation of electromagnetic waves

    Canuto, V. M.; Hartke, G. J.; Battaglia, A.; Chasnov, J.; Albrecht, G. F.

    1990-01-01

    In this paper, we apply two theoretical turbulence models, DIA and the recent GISS model, to study properties of a turbulent channel flow. Both models provide a turbulent kinetic energy spectral function E(k) as the solution of a non-linear equation; the two models employ the same source function but different closures. The source function is characterized by a rate n sub s (k) which is derived from the complex eigenvalues of the Orr-Sommerfeld (OS) equation in which the basic flow is taken to be of a Poiseuille type. The O-S equation is solved for a variety of Reynolds numbers corresponding to available experimental data. A physical argument is presented whereby the central line velocity characterizing the basic flow, U0 sup L, is not to be identified with the U0 appearing in the experimental Reynolds number. The theoretical results are compared with two types of experimental data: (1) turbulence bulk properties, and (2) properties that depend strongly on the structure of the turbulence spectrum at low wave numbers. The only existing analytical expression for Pi (k) cannot be used in the present case because it applies to the case of a flat plate, not a finite channel.

  15. Effect of Film Thickness and Physical Aging on “Intrinsic” Gas Permeation Properties of Microporous Ethanoanthracene-Based Polyimides

    Ma, Xiaohua

    2018-01-31

    Two ethanoanthracene-based dianhydrides, 9,10-dimethylethanoanthracene-2,3,6,7-tetracarboxylic anhydride (EA-DA) and its more flexible dibenzodioxane-containing derivative (EAD-DA), were synthesized from the same starting material, 9,10-dimethyl-ethanoanthracene-2,3,6,7-tetraol, and used for the preparation of bicyclic intrinsically microporous polyimides (PIM-PIs) by one-pot polycondensation reaction with 3,3′-dimethylnaphthidine (DMN). The resulting organosoluble polyimides, EA-DMN and EAD-DMN, were thermally stable up to 300 °C and had good mechanical properties with tensile strength of 55 and 63 MPa and elongation at break of 15 and 30%, respectively. EA-DMN and EAD-DMN polyimides displayed Brunauer–Emmett–Teller (BET) surface areas of 720 and 800 m2 g–1, respectively. Fresh films showed promising gas separation performance with very high gas permeabilities and moderate gas-pair selectivities, which were both strongly dependent on film thickness. The results obtained in this study shed more light on the relative importance of film thickness and physical aging on faster attainment of the “intrinsic” gas transport properties of high free volume PIM-PIs.

  16. Tritium permeation through iron

    Hagi, Hideki; Hayashi, Yasunori

    1989-01-01

    An experimental method for measuring diffusion coefficients and permeation rates of tritium in metals around room temperature has been established, and their values in iron have been obtained by using the method. Permeation rates of tritium and hydrogen through iron were measured by the electrochemical method in which a tritiated aqueous solution was used as a cathodic electrolyte. Tritium and hydrogen were introduced from one side of a membrane specimen by cathodic polarization, while at the other side of the specimen the permeating tritium and hydrogen were extracted by potentiostatical ionization. The amount of permeated hydrogen was obtained by integrating the anodic current, and that of tritium was determined by measuring the radioactivity of the electrolyte sampled from the extraction side. Diffusion coefficients of tritium (D T ) and hydrogen (D H ) were determined from the time lag of tritium and hydrogen permeation. D T =9x10 -10 m 2 /s and D H =4x10 -9 m 2 /s at 286 K for annealed iron specimens. These values of D T and D H were compared with the previous data of the diffusion coefficients of hydrogen and deuterium, and the isotope effect in diffusion was discussed. (orig.)

  17. Theoretical study on the electronic and optical properties of bulk and surface (001) InxGa1-xAs

    Liu, XueFei; Ding, Zhao; Luo, ZiJiang; Zhou, Xun; Wei, JieMin; Wang, Yi; Guo, Xiang; Lang, QiZhi

    2018-05-01

    The optical properties of surface and bulk InxGa1-xAs materials are compared systematically first time in this paper. The band structures, density of states and optical properties including dielectric function, reflectivity, absorption coefficient, loss function and refractive index of bulk and surface InxGa1-xAs materials are investigated by first-principles based on plane-wave pseudo-potentials method within the LDA approximation. The results agree well with the available theoretical and experimental studies and indicate that the electronic and optical properties of bulk and surface InxGa1-xAs materials are much different, and the results show that the considered optical properties of the both materials vary with increasing indium composition in an opposite way. The calculations show that the optical properties of surface In0.75Ga0.25As material are unexpected to be far from the other two indium compositions of surface InxGa1-xAs materials while the optical properties of bulk InxGa1-xAs materials vary with increasing indium composition in an expected regular way.

  18. Microwave processed bulk and nano NiMg ferrites: A comparative study on X-band electromagnetic interference shielding properties

    Chandra Babu Naidu, K., E-mail: chandrababu954@gmail.com [Ceramic Composite Laboratory, Centre for Crystal Growth, SAS, VIT University, Vellore 632014, Tamilnadu (India); Madhuri, W., E-mail: madhuriw12@gmail.com [Ceramic Composite Laboratory, Centre for Crystal Growth, SAS, VIT University, Vellore 632014, Tamilnadu (India); IFW, Leibniz Institute for Solid State and Materials Research, Technische Universität Dresden, 01069 Dresden (Germany)

    2017-02-01

    Bulk and nano Ni{sub 1-x}Mg{sub x}Fe{sub 2}O{sub 4} (x = 0–1) samples were synthesized via microwave double sintering and microwave assisted hydrothermal techniques respectively. The diffraction pattern confirmed the formation of cubic spinel phases in case of both the ferrites. The larger bulk densities were achieved to the bulk than that of nano. In addition, a comparative study on X-band (8.4–12 GHz) electromagnetic interference shielding properties of current bulk and nanomaterials was elucidated. The results showed that the bulk Ni{sub 0.6}Mg{sub 0.4}Fe{sub 2}O{sub 4} composition revealed the highest total shielding efficiency (SE{sub T}) of ∼17 dB. In comparison, the shielding efficiency values of all bulk contents were higher than that of nano because of larger bulk densities. Moreover, the ac-electromagnetic parameters such as electrical conductivity (σ{sub ac}), the respective real (ε′ & μ′) and imaginary parts (ε″ & μ″) of complex permittivity and permeability were investigated as a function of gigahertz frequency. The bulk ferrites of x = 0.4 & 0.6 showed the high ε″ of 10.26 & 6.71 and μ″ of 3.65 & 3.09 respectively at 12 GHz which can work as promising microwave absorber materials. Interestingly, nanoferrites exhibited negative μ″ values at few frequencies due to geometrical effects which improves the microwave absorption. - Highlights: • Bulk and nano NiMg ferrites are prepared by microwave and hydrothermal method. • X-band EMI shielding properties are studied for both bulk and nano ferrites. • Bulk Ni{sub 0.6}Mg{sub 0.4}Fe{sub 2}O{sub 4} revealed the highest SE{sub T} of ∼17 dB at 8.4 GHz. • Bulk x = 0.4 & 0.6 showed the high ε″ and μ″ at 12 GHz for absorber applications.

  19. On Diffusion and Permeation

    Peppin, Stephen S. L.

    2009-01-01

    Diffusion and permeation are discussed within the context of irreversible thermodynamics. A new expression for the generalized Stokes-Einstein equation is obtained which links the permeability to the diffusivity of a two-component solution and contains the poroelastic Biot-Willis coefficient. The theory is illustrated by predicting the concentration and pressure profiles during the filtration of a protein solution. At low concentrations the proteins diffuse independently while at higher concentrations they form a nearly rigid porous glass through which the fluid permeates. The theoretically determined pressure drop is nonlinear in the diffusion regime and linear in the permeation regime, in quantitative agreement with experimental measurements. © 2009 Walter de Gruyter, Berlin, New York.

  20. Improving magnetic properties of MgB{sub 2} bulk superconductors by synthetic engine oil treatment

    Taylan Koparan, E., E-mail: etaylan20@gmail.com [Department of Science Education, Eregli Faculty of Education, Bulent Ecevit University, TR-67300, Zonguldak (Turkey); Savaskan, B. [Energy Systems Engineering, Faculty of Technology, Karadeniz Technical University, 61830, Of, Trabzon (Turkey); Yanmaz, E. [Department of Mechatronics, Faculty of Engineering and Architecture, İstanbul Gelişim University, İstanbul (Turkey)

    2016-08-15

    Highlights: • The effects of synthetic engine oil treatment on magnetic properties of bulk MgB{sub 2} superconductors has been first time investigated and reported. • Synthetic engine oil used as a product which is cheap and a rich carbon source obviously has improved the superconducting magnetic properties of MgB{sub 2}. • The critical current density of all of MgB{sub 2} samples immersed at different standby time in engine oil in whole field range has been better than that of the pure MgB{sub 2} sample. • The MgB{sub 2} sample immersed at 300 min standby time in synthetic engine oil has the best performance compared to other samples. - Abstract: The present study focuses on the effects of standby time of the MgB{sub 2} samples immersed in synthetic engine oil on the critical current density ( J{sub c}(H)), magnetic field dependence of the pinning force density f{sub p}(b) and T{sub c} performances of MgB{sub 2} bulk superconductors. Synthetic engine oil was used as a product which is cheap and a rich carbon source. Manufactured MgB{sub 2} pellet samples were immersed at different standby time of 30 min, 120 min, 300 min and 1440 min in synthetic engine oil after the first heating process. Finally, MgB{sub 2} samples immersed in synthetic engine oil were sintered at 1000 °C and kept for 15 min in Ar atmosphere. The critical current density of all of MgB{sub 2} samples immersed at different standby time in engine oil in whole field range was better than that of the pure MgB{sub 2} sample because of the number of the pinning centers. The MgB{sub 2} sample immersed at 300 min standby time in synthetic engine oil has the best performance compared to other samples. The J{sub c} value for the pure sample is 2.0 × 10{sup 3} A/cm{sup 2}, whereas for the MgB{sub 2} sample immersed at 300 min standby time in engine oil the J{sub c} is enhanced to 4.8 × 10{sup 3} A/cm{sup 2} at 5 K and 3 T. The superconducting transition temperature (T{sub c}) did not change

  1. Improving magnetic properties of MgB_2 bulk superconductors by synthetic engine oil treatment

    Taylan Koparan, E.; Savaskan, B.; Yanmaz, E.

    2016-01-01

    Highlights: • The effects of synthetic engine oil treatment on magnetic properties of bulk MgB_2 superconductors has been first time investigated and reported. • Synthetic engine oil used as a product which is cheap and a rich carbon source obviously has improved the superconducting magnetic properties of MgB_2. • The critical current density of all of MgB_2 samples immersed at different standby time in engine oil in whole field range has been better than that of the pure MgB_2 sample. • The MgB_2 sample immersed at 300 min standby time in synthetic engine oil has the best performance compared to other samples. - Abstract: The present study focuses on the effects of standby time of the MgB_2 samples immersed in synthetic engine oil on the critical current density ( J_c(H)), magnetic field dependence of the pinning force density f_p(b) and T_c performances of MgB_2 bulk superconductors. Synthetic engine oil was used as a product which is cheap and a rich carbon source. Manufactured MgB_2 pellet samples were immersed at different standby time of 30 min, 120 min, 300 min and 1440 min in synthetic engine oil after the first heating process. Finally, MgB_2 samples immersed in synthetic engine oil were sintered at 1000 °C and kept for 15 min in Ar atmosphere. The critical current density of all of MgB_2 samples immersed at different standby time in engine oil in whole field range was better than that of the pure MgB_2 sample because of the number of the pinning centers. The MgB_2 sample immersed at 300 min standby time in synthetic engine oil has the best performance compared to other samples. The J_c value for the pure sample is 2.0 × 10"3 A/cm"2, whereas for the MgB_2 sample immersed at 300 min standby time in engine oil the J_c is enhanced to 4.8 × 10"3 A/cm"2 at 5 K and 3 T. The superconducting transition temperature (T_c) did not change with the increasing standby time of the samples in synthetic engine oil at all. The best diamagnetic property was

  2. Study of optical properties of bulk GaN crystals grown by HVPE

    Gu, Hong; Ren, Guoqiang; Zhou, Taofei; Tian, Feifei; Xu, Yu; Zhang, Yumin; Wang, Mingyue; Zhang, Zhiqiang [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Cai, Demin [Suzhou Nanowin Science and Technology Co., Ltd., Suzhou 215123 (China); Wang, Jianfeng [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Suzhou Nanowin Science and Technology Co., Ltd., Suzhou 215123 (China); Xu, Ke, E-mail: kxu2006@sinano.ac.cn [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Suzhou Nanowin Science and Technology Co., Ltd., Suzhou 215123 (China)

    2016-07-25

    We investigated the optical properties of a series of GaN samples sliced from the same bulk crystal grown using hydride vapor phase epitaxy. The high crystalline quality of the samples was evaluated using cathodoluminescence measurements, and the dislocation density ranged from 2.4 × 10{sup 6} to 2.3 × 10{sup 5} cm{sup −2}. The impurity concentration was determined using secondary-ion mass spectroscopy, and photoluminescence (PL) measurements were conducted in the range of 3–300 K. We did not find a correlation between the O or C impurities and the weak yellow luminescence (YL) band. As the dislocation density decreased, the intensity of the band edge emission increased and that of the YL band decreased. A competition between the two-electron satellite lines correlated to Si and the YL band was also observed in the low-temperature PL spectra, which demonstrated that the Si impurity also plays an important role in the weak YL band of these GaN samples. These results indicate that the Si donors around the dislocations, as reasonable sources of shallow donors, will recombine with possible deep acceptors and finally respond with the YL. - Highlights: • The investigated samples were sliced from the same bulk crystal. • No correlation between the O or C impurities and the weak YL band is observed. • A well-regulated relationship between the YL band and the dislocations is found. • A competition between the TES-Si lines and the YL band is discussed. • The dislocations trapping Si impurity is suggested to be responsible for YL band.

  3. Physical properties of the GaPd2 intermetallic catalyst in bulk and nanoparticle morphology

    Wencka, M.; Schwerin, J.; Klanjšek, M.

    2015-01-01

    Intermetallic compound GaPd2 is a highly selective catalyst material for the semi-hydrogenation of acetylene. We have determined anisotropic electronic, thermal and magnetic properties of a GaPd2 monocrystal along three orthogonal orthorhombic directions of the structure. By using 69Ga and 71Ga NMR...... properties of the GaPd2 phase on going from the bulk material to the nanoparticles morphology, we have synthesized GaPd2/SiO2 supported nanoparticles and determined their electronic DOS at εF from the 71Ga NMR spin-lattice relaxation rate. The electronic DOS of the GaPd2 was also studied theoretically from...... spectroscopy, we have determined the electric-field-gradient tensor at the Ga site in the unit cell and the Knight shift, which yields the electronic density of states (DOS) at the Fermi energy εF. The DOS at εF was determined independently also from the specific heat. To see the change of electronic...

  4. Structure–property relationships of oligothiophene–isoindigo polymers for efficient bulk-heterojunction solar cells

    Ma, Zaifei

    2014-01-01

    A series of alternating oligothiophene (nT)-isoindigo (I) copolymers (PnTI) were synthesized to investigate the influence of the oligothiophene block length on the photovoltaic (PV) properties of PnTI:PCBM bulk-heterojunction blends. Our study indicates that the number of thiophene rings (n) in the repeating unit alters both polymer crystallinity and polymer-fullerene interfacial energetics, which results in a decreasing open-circuit voltage (Voc) of the solar cells with increasing n. The short-circuit current density (Jsc) of P1TI:PCBM devices is limited by the absence of a significant driving force for electron transfer. Instead, blends based on P5TI and P6TI feature large polymer domains, which limit charge generation and thus Jsc. The best PV performance with a power conversion efficiency of up to 6.9% was achieved with devices based on P3TI, where a combination of a favorable morphology and an optimal interfacial energy level offset ensures efficient exciton separation and charge generation. The structure-property relationship demonstrated in this work would be a valuable guideline for the design of high performance polymers with small energy losses during the charge generation process, allowing for the fabrication of efficient solar cells that combine a minimal loss in Voc with a high Jsc. © 2014 The Royal Society of Chemistry.

  5. Ku-band electromagnetic wave absorbing properties of polysiloxane derived Si-O-C bulk ceramics

    Ding, Donghai; Li, Zipei; Xiao, Guoqing; Yang, Shaoyu

    2018-02-01

    The bulk Si-O-C ceramics were prepared by polymer derived ceramics (PDCs) route using polysiloxane as precursor and their properties were investigated for electromagnetic wave absorbing in the frequency range of 12.4-18 GHz (Ku-band). It was found that the catalytic pyrolysis can enhance substantially the absorbing properties by in situ formation of turbostratic carbon network, ordered carbon, and multi-wall carbon nanotubes. The matching thickness of sample containing 1.5 wt% FeCl3 (FPSO-1.5) is 2.2 mm, and its reflection loss exceeds -10 dB in the whole Ku-band with an absorption peak of -35.48 dB at 14.16 GHz. For sample containing 1.5 wt% FeCl3, its absorption peak increases to -15.78 dB, but its matching thickness decreases significantly to 2.2 mm. The polymer derived Si-O-C ceramics could be used as excellent electromagnetic functional devices working in harsh environments.

  6. Magnetic properties and microstructural homogeneity in NdFeAl bulk metallic glasses

    Ortega-Zempoalteca, R.; Valenzuela, R.; Betancourt, I.

    2011-01-01

    Bulk metallic glasses of nominal composition Nd 60 Fe 30 Al 10 were prepared by copper mold casting in the form of rods of 3 mm in diameter and 50 mm in length. Preparation conditions were varied to assess the effects of the injection distance and the injection pressure of the melt. In order to determine their microstructure, disk-shaped samples were obtained from different cut zones along the axis rod. A non-homogeneous phase distribution was observed, which resulted from the heat transfer regime during the cooling of the melt in the copper mold. As expected, the nature, distribution and volumetric fraction of the various phases produced play an important role on the resulting magnetic properties. Among the main observed phases are Fe-rich rod-like crystals, Nd-rich dendritic crystals and a ''like-amorphous'' matrix. The hard magnetic properties of these materials can be associated with this matrix. In these cooling regimes, the coercive field increases as the cooling rate of the amorphous matrix increases. Hysteresis loops showed a high degree of coupling between phases with different magnetic order. Both the coercive field and the magnetization showed a significant variation along the rod axis; a maximum appeared as a function of the axis length. In order to gather more information about the coupling between the observed phases, δM (or Henkel) plots were obtained, showing an exchange character for interactions (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Evolution of the bulk optical properties of bovine muscles during wet aging.

    Van Beers, Robbe; Kokawa, Mito; Aernouts, Ben; Watté, Rodrigo; De Smet, Stefaan; Saeys, Wouter

    2018-02-01

    The bulk optical properties (BOP) of two bovine muscles were studied in the 500nm to 1850nm wavelength range. Over a two-week period of wet aging, the BOP of the biceps femoris (BF) and longissimus lumborum (LL) were determined and related to moisture content, tenderness and cooking loss. The absorption by myoglobin and reduced scattering coefficient were higher in the BF compared to the LL. The scattering anisotropy factor was relatively high (>0.95 for LL), representing dominant forward scattering. Two-toning effects in the BF could be attributed to significant scattering differences, as no differences in absorption properties were observed. During wet aging, the anisotropy factor decreased, while tenderness increased. It was hypothesized that this might be related to proteolysis of cytoskeletal proteins. The results show the potential use of BOP to monitor tenderization and the cause of color differences in beef muscles. Moreover, this information could be used to develop and optimize optical sensors for non-destructive meat quality monitoring. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Bulk properties and near-critical behaviour of SiO2 fluid

    Green, Eleanor C. R.; Artacho, Emilio; Connolly, James A. D.

    2018-06-01

    Rocky planets and satellites form through impact and accretion processes that often involve silicate fluids at extreme temperatures. First-principles molecular dynamics (FPMD) simulations have been used to investigate the bulk thermodynamic properties of SiO2 fluid at high temperatures (4000-6000 K) and low densities (500-2240 kg m-3), conditions which are relevant to protoplanetary disc condensation. Liquid SiO2 is highly networked at the upper end of this density range, but depolymerises with increasing temperature and volume, in a process characterised by the formation of oxygen-oxygen (Odbnd O) pairs. The onset of vaporisation is closely associated with the depolymerisation process, and is likely to be non-stoichiometric at high temperature, initiated via the exsolution of O2 molecules to leave a Si-enriched fluid. By 6000 K the simulated fluid is supercritical. A large anomaly in the constant-volume heat capacity occurs near the critical temperature. We present tabulated thermodynamic properties for silica fluid that reconcile observations from FPMD simulations with current knowledge of the SiO2 melting curve and experimental Hugoniot curves.

  9. Pure- and mixed-gas propylene/propane permeation properties of spiro- and triptycene-based microporous polyimides

    Swaidan, Ramy J.; Ghanem, Bader; Swaidan, Raja; Litwiller, Eric; Pinnau, Ingo

    2015-01-01

    Solution-processable polyimides of intrinsic microporosity (PIM-PIs) comprising relatively inflexible and contorted backbones have demonstrated outstanding molecular-sieving behavior in membrane-based separation of gas/gas pairs. In this work, the effects of systematically increasing intra-chain rigidity on the propylene/propane separation properties were compared for PIM-PIs made from 2,3,5,6-tetramethyl-1,4-phenylene diamine (TMPD) and (i) spiro-centered dianhyride (SPDA-TMPD or PIM-PI-1) and (ii) 9,10-diisopropyltriptycene-based dianhydride (TPDA-TMPD or KAUST PI-1). Pure-gas experiments at 2 bar and 35 oC showed significant increases in C3H6 permeability and C3H6/C3H8 selectivity by transitioning from PIM-PI-1 (P(C3H6)=393 Barrer, α(C3H6/C3H8)=6) to KAUST-PI-1 (P(C3H6)=817 Barrer, α(C3H6/C3H8)=16), positioning KAUST-PI-1 considerably above the experimentally observed pure-gas C3H6/C3H8 polymer upper bound. However, 50:50 C3H6/C3H8 mixed-gas feeds induced significant losses in C3H6 permeability and C3H6/C3H8 selectivity relative to the 2 bar pure-gas data for PIM-PI-1 and KAUST-PI-1 as the C3H6/C3H8 selectivity dropped from 6 to 3 and 16 to 5, respectively, at 2 bar C3H6 partial pressure due to plasticization and competitive sorption.

  10. Pure- and mixed-gas propylene/propane permeation properties of spiro- and triptycene-based microporous polyimides

    Swaidan, Ramy Jawdat

    2015-06-03

    Solution-processable polyimides of intrinsic microporosity (PIM-PIs) comprising relatively inflexible and contorted backbones have demonstrated outstanding molecular-sieving behavior in membrane-based separation of gas/gas pairs. In this work, the effects of systematically increasing intra-chain rigidity on the propylene/propane separation properties were compared for PIM-PIs made from 2,3,5,6-tetramethyl-1,4-phenylene diamine (TMPD) and (i) spiro-centered dianhyride (SPDA-TMPD or PIM-PI-1) and (ii) 9,10-diisopropyltriptycene-based dianhydride (TPDA-TMPD or KAUST PI-1). Pure-gas experiments at 2 bar and 35 oC showed significant increases in C3H6 permeability and C3H6/C3H8 selectivity by transitioning from PIM-PI-1 (P(C3H6)=393 Barrer, α(C3H6/C3H8)=6) to KAUST-PI-1 (P(C3H6)=817 Barrer, α(C3H6/C3H8)=16), positioning KAUST-PI-1 considerably above the experimentally observed pure-gas C3H6/C3H8 polymer upper bound. However, 50:50 C3H6/C3H8 mixed-gas feeds induced significant losses in C3H6 permeability and C3H6/C3H8 selectivity relative to the 2 bar pure-gas data for PIM-PI-1 and KAUST-PI-1 as the C3H6/C3H8 selectivity dropped from 6 to 3 and 16 to 5, respectively, at 2 bar C3H6 partial pressure due to plasticization and competitive sorption.

  11. Physical properties of Zr50Cu40-xAl10Pdx bulk glassy alloys

    Wencka, M.; Jagodic, M.; Gradisek, A.; Kocjan, A.; Jaglicic, Z.; McGuiness, P.J.; Apih, T.; Yokoyama, Y.; Dolinsek, J.

    2010-01-01

    It was shown recently (Yokoyama et al. ) that the addition of a small amount of Pd to the Zr 50 Cu 40 Al 10 bulk glassy alloy (BGA) has a beneficial effect on fatigue-strength enhancement, where the composition Zr 50 Cu 37 Al 10 Pd 3 behaved in a resonant-like way by showing the highest fatigue limit of 1050 MPa and the minimum Vickers hardness. We performed a study of the magnetic properties, the specific heat, the electrical resistivity and the hydrogen-diffusion constant for a series of compositions Zr 50 Cu 40-x Al 10 Pd x (x = 0-7 at.%), in order to determine their physical properties and to check for the influence of the Pd content on these properties. The Zr 50 Cu 40-x Al 10 Pd x BGAs are nonmagnetic, conducting alloys, where the Pauli spin susceptibility of the conduction electrons is the only source of paramagnetism. The low-temperature specific heat indicates an enhancement of the conduction-electron effective mass m* below 5 K, suggesting that the Zr 50 Cu 40-x Al 10 Pd x BGAs are not free-electron-like compounds. The electrical resistivities of the Zr 50 Cu 40-x Al 10 Pd x BGAs amount to about 200 μΩ cm and show a small, negative temperature coefficient (NTC) with an increase from 300 to 2 K of 4%. The hydrogen self-diffusion constant D in hydrogen-loaded samples shows classical over-barrier-hopping temperature dependence and is of comparable magnitude to the related icosahedral and amorphous Zr 69.5 Cu 12 Ni 11 Al 7.5 hydrogen-storage alloys. No correlation between the investigated physical parameters and the Pd content of the samples could be observed.

  12. Hydrogen permeation properties of Pd-coated V89.8Cr 10Y0.2 alloy membrane using WGS reaction gases

    Jeon, Sungil

    2013-05-01

    The influence of co-existing gases on the hydrogen permeation was studied through a Pd-coated V89.8Cr10Y0.2 alloy membrane. Preliminary hydrogen permeation experiments have been confirmed that hydrogen flux was 6.26 ml/min/cm2 for a Pd-coated V 89.8Cr10Y0.2 alloy membrane (thick: 0.5 mm) using pure hydrogen as feed gas. Also, the hydrogen permeation flux decreased with decrease of hydrogen partial pressure at constant pressure when H 2/CO2 and H2/CO2/H2S mixture applied as feed gas respectively and permeation fluxes were satisfied with Sievert\\'s law in different feed conditions. It was found from XRD and SEM results after permeation test that the Pd-coated V89.8Cr 10Y0.2 alloy membrane had good stability and durability for various mixture feeding conditions. Copyright © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  13. Hydrogen permeation properties of Pd-coated V89.8Cr 10Y0.2 alloy membrane using WGS reaction gases

    Jeon, Sungil; Park, Junghoon

    2013-01-01

    The influence of co-existing gases on the hydrogen permeation was studied through a Pd-coated V89.8Cr10Y0.2 alloy membrane. Preliminary hydrogen permeation experiments have been confirmed that hydrogen flux was 6.26 ml/min/cm2 for a Pd-coated V 89.8Cr10Y0.2 alloy membrane (thick: 0.5 mm) using pure hydrogen as feed gas. Also, the hydrogen permeation flux decreased with decrease of hydrogen partial pressure at constant pressure when H 2/CO2 and H2/CO2/H2S mixture applied as feed gas respectively and permeation fluxes were satisfied with Sievert's law in different feed conditions. It was found from XRD and SEM results after permeation test that the Pd-coated V89.8Cr 10Y0.2 alloy membrane had good stability and durability for various mixture feeding conditions. Copyright © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  14. Modification of the bulk properties of the porous poly(lactide-co-glycolide) scaffold by irradiation with a cyclotron ion beam with high energy for its application in tissue engineering

    Woo, Jung Hoon; Kim, Do Yeon; Jo, Seong Yeun; Kang, Hyunki; Noh, Insup

    2009-01-01

    Understanding the bulk properties of a prefabricated scaffold for handling and degradation during cell culture may be advantageous to its application in tissue engineering. Modification of the bulk properties of the porous poly(lactide-co-glycolide) (PLGA) scaffold was performed by irradiation with a high energy cyclotron proton ion beam. The porous PLGA scaffolds were fabricated in advance by the gas-foaming method by employing ammonium bicarbonate particles as porogens. Irradiation with ion beams was performed with 40 MeV for 3, 6 and 9 min on the scaffolds at a distance of 30 cm from the beam exit to the scaffold surface. The bulk area of the ion beam-treated PLGA scaffold apparently demonstrated no color changes when observed with a digital camera. The chemical structures of the untreated samples seemed to be kept well when analyzed by both Fourier transformed infrared but a subtle change was observed in its x-ray photoelectron spectroscopy. The results of in vitro tissue culture with smooth muscle cells for up to 4 weeks also demonstrated no significant difference in terms of its handling stability during cell culture and cellular behavior between the untreated PLGA scaffolds and the ion beam-treated ones. However, significant changes were observed in its molecular weight as measured by gel permeation chromatography, indicating a significant reduction of its molecular weights. These results of in vitro tests and GPC measurements indicated that while bulk modification of the scaffold was processed, its handling was stable during in vitro cell culture for up to 4 weeks.

  15. Modification of the bulk properties of the porous poly(lactide-co-glycolide) scaffold by irradiation with a cyclotron ion beam with high energy for its application in tissue engineering

    Woo, Jung Hoon; Kim, Do Yeon; Jo, Seong Yeun; Kang, Hyunki; Noh, Insup, E-mail: insup@snut.ac.k [Department of Chemical Engineering, Seoul National University of Technology, 172 Gongnung 2-dong, Nowon-gu, Seoul 139-743 (Korea, Republic of)

    2009-08-15

    Understanding the bulk properties of a prefabricated scaffold for handling and degradation during cell culture may be advantageous to its application in tissue engineering. Modification of the bulk properties of the porous poly(lactide-co-glycolide) (PLGA) scaffold was performed by irradiation with a high energy cyclotron proton ion beam. The porous PLGA scaffolds were fabricated in advance by the gas-foaming method by employing ammonium bicarbonate particles as porogens. Irradiation with ion beams was performed with 40 MeV for 3, 6 and 9 min on the scaffolds at a distance of 30 cm from the beam exit to the scaffold surface. The bulk area of the ion beam-treated PLGA scaffold apparently demonstrated no color changes when observed with a digital camera. The chemical structures of the untreated samples seemed to be kept well when analyzed by both Fourier transformed infrared but a subtle change was observed in its x-ray photoelectron spectroscopy. The results of in vitro tissue culture with smooth muscle cells for up to 4 weeks also demonstrated no significant difference in terms of its handling stability during cell culture and cellular behavior between the untreated PLGA scaffolds and the ion beam-treated ones. However, significant changes were observed in its molecular weight as measured by gel permeation chromatography, indicating a significant reduction of its molecular weights. These results of in vitro tests and GPC measurements indicated that while bulk modification of the scaffold was processed, its handling was stable during in vitro cell culture for up to 4 weeks.

  16. Correlation between structural, electrical and magnetic properties of GdMnO3 bulk ceramics

    Samantaray, S.; Mishra, D.K.; Pradhan, S.K.; Mishra, P.; Sekhar, B.R.; Behera, Debdhyan; Rout, P.P.; Das, S.K.; Sahu, D.R.; Roul, B.K.

    2013-01-01

    This paper reports the effect of sintering temperature on ferroelectric properties of GdMnO 3 (GMO) bulk ceramics at room temperature prepared by the conventional solid state reaction route following slow step sintering schedule. Ferroelectric hysteresis loop as well as sharp dielectric anomaly in pure (99.999%) GMO sintered ceramics has been clearly observed. Samples sintered at 1350 °C become orthorhombic with Pbnm space group and showed frequency independent sharp dielectric anomalies at 373 K and a square type of novel ferroelectric hysteresis loop was observed at room temperature. Interestingly, dielectric anomalies and ferroelectric behavior were observed to be dependent upon sintering temperature of GdMnO 3 . Room temperature dielectric constant (ε r ) value at different frequencies is observed to be abnormally high. The magnetic field and temperature dependent magnetization show antiferromagnetic behavior at 40 K for both 1350 °C and 1700 °C sintered GMO. Present findings showed the possibility of application of GdMnO 3 at room temperature as multifunctional materials. - Highlights: • Preparation of single-phasic polycrystalline GdMnO 3 sample by the solid state sintering route. • Observation of square type P–E hysteresis loop with higher saturation and remnant polarization. • Observation of antiferromagnetic behavior at 40 K in polycrystalline GdMnO 3 . • Possibility of room temperature application of GdMnO 3 as multifunctional material

  17. Correlation between structural, electrical and magnetic properties of GdMnO{sub 3} bulk ceramics

    Samantaray, S. [Institute of Materials Science, Planetarium Building, Bhubaneswar 751013, Odisha (India); Mishra, D.K. [Department of Physics, Institute of Technical Education and Research, S ‘O’ A University, Bhubaneswar 751030, Odisha (India); Pradhan, S.K. [Institute of Materials Science, Planetarium Building, Bhubaneswar 751013, Odisha (India); Mishra, P.; Sekhar, B.R. [Institue of Physics, Sachivalaya Marg, Bhubaneswar, Odisha (India); Behera, Debdhyan [Advanced Materials Technology Department, CSIR-Institute of Minerals and Materials Technology, Bhubaneswar 751013, Odisha (India); Rout, P.P.; Das, S.K. [Institute of Materials Science, Planetarium Building, Bhubaneswar 751013, Odisha (India); Sahu, D.R. [School of Physics, University of the Witwatersrand, Johannesburg (South Africa); Roul, B.K., E-mail: ims@iopb.res.in [Institute of Materials Science, Planetarium Building, Bhubaneswar 751013, Odisha (India)

    2013-08-15

    This paper reports the effect of sintering temperature on ferroelectric properties of GdMnO{sub 3} (GMO) bulk ceramics at room temperature prepared by the conventional solid state reaction route following slow step sintering schedule. Ferroelectric hysteresis loop as well as sharp dielectric anomaly in pure (99.999%) GMO sintered ceramics has been clearly observed. Samples sintered at 1350 °C become orthorhombic with Pbnm space group and showed frequency independent sharp dielectric anomalies at 373 K and a square type of novel ferroelectric hysteresis loop was observed at room temperature. Interestingly, dielectric anomalies and ferroelectric behavior were observed to be dependent upon sintering temperature of GdMnO{sub 3}. Room temperature dielectric constant (ε{sub r}) value at different frequencies is observed to be abnormally high. The magnetic field and temperature dependent magnetization show antiferromagnetic behavior at 40 K for both 1350 °C and 1700 °C sintered GMO. Present findings showed the possibility of application of GdMnO{sub 3} at room temperature as multifunctional materials. - Highlights: • Preparation of single-phasic polycrystalline GdMnO{sub 3} sample by the solid state sintering route. • Observation of square type P–E hysteresis loop with higher saturation and remnant polarization. • Observation of antiferromagnetic behavior at 40 K in polycrystalline GdMnO{sub 3}. • Possibility of room temperature application of GdMnO{sub 3} as multifunctional material.

  18. AC Calorimetry and Thermophysical Properties of Bulk Glass-Forming Metallic Liquids

    Johnson, William L.

    2000-01-01

    Thermo-physical properties of two bulk metallic glass forming alloys, Ti34Zr11Cu47Ni8 (VIT 101) and Zr57Nb5Ni12.6Al10CU15.4 (VIT 106), were investigated in the stable and undercooled melt. Our investigation focused on measurements of the specific heat in the stable and undercooled liquid using the method of AC modulation calorimetry. The VIT 106 exhibited a maximum undercooling of 140 K in free radiative cooling. Specific heat measurements could be performed in stable melt down to an undercooling of 80 K. Analysis of the specific heat data indicate an anomaly near the equilibrium liquidus temperature. This anomaly is also observed in y the temperature dependencies of the external relaxation time, the specific volume, and the surface tension; it is tentatively attributed to a phase separation in the liquid state. The VIT 101 specimen exhibited a small undercooling of about 50 K. Specific heat measurements were performed in the stable and undercooled melt. These various results will be combined with ground based work such as the measurement of T-T-T curves in the electrostatic levitator and low temperature viscosity and specific heat measurements for modeling the nucleation kinetics of these alloys.

  19. Bulk-Like Electrical Properties Induced by Contact-Limited Charge Transport in Organic Diodes: Revised Space Charge Limited Current

    Xu, Guangwei

    2018-02-22

    Charge transport governs the operation and performance of organic diodes. Illuminating the charge-transfer/transport processes across the interfaces and the bulk organic semiconductors is at the focus of intensive investigations. Traditionally, the charge transport properties of organic diodes are usually characterized by probing the current–voltage (I–V) curves of the devices. However, to unveil the landscape of the underlying potential/charge distribution, which essentially determines the I–V characteristics, still represents a major challenge. Here, the electrical potential distribution in planar organic diodes is investigated by using the scanning Kelvin probe force microscopy technique, a method that can clearly separate the contact and bulk regimes of charge transport. Interestingly, by applying to devices based on novel, high mobility organic materials, the space-charge-limited-current-like I–V curves, which are previously believed to be a result of the bulk transport, are surprisingly but unambiguously demonstrated to be caused by contact-limited conduction. A model accounting is developed for the transport properties of both the two metal/organic interfaces and the bulk. The results indicate that pure interface-dominated transport can indeed give rise to I–V curves similar to those caused by bulk transport. These findings provide a new insight into the charge injection and transport processes in organic diodes.

  20. Ab-initio investigation of structural, electronic and optical properties BSb compound in bulk and surface (110 states

    H A Badehian

    2015-07-01

    Full Text Available In recent work the structural, electronic and optical properties of BSb compound in bulk and surface (110 states have been studied. Calculations have been performed using Full-Potential Augmented Plane Wave (FP-LAPW method by WIEN2k code in Density Functional Theory (DFT framework. The structural properties of the bulk such as lattice constant, bulk module and elastic constants have been investigated using four different approximations. The band gap energy of the bulk and the (110 surface of BSb were obtained about 1.082 and 0.38 eV respectively. Moreover the surface energy, the work function, the surface relaxation, surface state and the band structure of BSb (110 were investigated using symmetric and stoichiometric 15 layers slabs with the vacuum of 20 Bohr. In addition, the real and imaginary parts of the dielectric function of the bulk and the BSb (110 slab were calculated and compared to each other. Our obtained results have a good agreement with the available results.

  1. Glass formation, magnetic properties and magnetocaloric effect of ternary Ho–Al–Co bulk metallic glass

    Zhang, Huiyan; Li, Ran; Ji, Yunfei; Liu, Fanmao; Luo, Qiang; Zhang, Tao

    2012-01-01

    A ternary Ho–Al–Co system with high glass-forming ability (GFA) was developed and fully glassy rods with diameters up to 1 cm can be produced for the best glass former of Ho 55 Al 27.5 Co 17.5 alloy. The thermal stability and low-temperature magnetic properties of the Ho 55 Al 27.5 Co 17.5 bulk metallic glass (BMG) were studied. The magnetic transition temperature of this alloy is ∼14 K as determined by the thermomagnetic measurement. Two indicators, i.e. isothermal magnetic entropy change (ΔS M ) and the relative cooling power (RCP), were adopted to evaluate the magnetocaloric effect (MCE) of the alloy under a low magnetic field up to 2 T, which can be generated by permanent magnets. The values of |ΔS M | and RCP are 7.98 J kg −1 K −1 and 191.5 J kg −1 , respectively. The Ho 55 Al 27.5 Co 17.5 BMG with good MCE and high GFA provides an attractive candidate for magnetic refrigeration applications, like hydrogen liquefaction and storage. - Highlights: ► A ternary Ho–Al–Co BMG system with high glass-forming ability was developed. ► Fully glassy rods of Ho 55 Al 27.5 Co 17.5 alloy were produced up to 1 cm in diameter. ► The thermal stability and magnetic properties of the BMG were evaluated. ► The BMG exhibits good magnetocaloric effect under a low magnetic field up to 2 T.

  2. Structural and mechanical properties of a giomer-based bulk fill restorative in different curing conditions

    Mustafa Sarp Kaya

    2018-01-01

    Full Text Available ABSTRACT Objective: The main goal of this study was to compare the polymerization degree of bulk-fill giomer resin cured with three different light-curing units (LCUs: a polywave third-generation (Valo; a monowave (DemiUltra: DU; and a second-generation LED (Optima 10: Opt LCUs by using structural and mechanical properties. Material and methods: Giomer samples of 2 and 4 mm cured with three LCUs were employed in vitro analysis. The degree of curing (DC% was determined with Fourier-Transform Infrared Spectroscopy (FTIR. Microstructural features were observed with scanning electron microscopy (SEM. Flexural strength (FS, compression strength (CS, elastic modulus and fracturing strain were determined for mechanical properties. Surface microhardness (SMH values were also measured. Oneway ANOVA, two-way analysis of variance and Tukey multiple comparison tests were used for statistically analyzing the FS and SMH. Results: DC% values were 58.2, 47.6, and 39.7 for the 2 mm samples cured with DU, Opt., and Valo LCUs, respectively. DC% values of the 4 mm samples were 50.4, 44.6, and 38.2 for DU, Opt, and Valo, respectively. SMH values were Valo, Opt

  3. Centrality dependence of bulk fireball properties in √(sNN)=200 GeV Au-Au collisions

    Rafelski, Johann; Letessier, Jean; Torrieri, Giorgio

    2005-01-01

    We explore the centrality dependence of the properties of the dense hadronic matter created in √(s NN )=200 GeV Au-Au collisions at the Relativistic Heavy Ion Collider. Using the statistical hadronization model, we fit particle yields known for 11 centrality bins. We present the resulting model parameters, rapidity yields of physical quantities, and the physical properties of bulk matter at hadronization as function of centrality. We discuss the production of strangeness and entropy

  4. Hydrogen gas driven permeation through tungsten deposition layer formed by hydrogen plasma sputtering

    Uehara, Keiichiro; Katayama, Kazunari; Date, Hiroyuki; Fukada, Satoshi

    2015-01-01

    Highlights: • H permeation tests for W layer formed by H plasma sputtering are performed. • H permeation flux through W layer is larger than that through W bulk. • H diffusivity in W layer is smaller than that in W bulk. • The equilibrium H concentration in W layer is larger than that in W bulk. - Abstract: It is important to evaluate the influence of deposition layers formed on plasma facing wall on tritium permeation and tritium retention in the vessel of a fusion reactor from a viewpoint of safety. In this work, tungsten deposition layers having different thickness and porosity were formed on circular nickel plates by hydrogen RF plasma sputtering. Hydrogen permeation experiment was carried out at the temperature range from 250 °C to 500 °C and at hydrogen pressure range from 1013 Pa to 101,300 Pa. The hydrogen permeation flux through the nickel plate with tungsten deposition layer was significantly smaller than that through a bare nickel plate. This indicates that a rate-controlling step in hydrogen permeation was not permeation through the nickel plate but permeation though the deposition layer. The pressure dependence on the permeation flux differed by temperature. Hydrogen permeation flux through tungsten deposition layer is larger than that through tungsten bulk. From analysis of the permeation curves, it was indicated that hydrogen diffusivity in tungsten deposition layer is smaller than that in tungsten bulk and the equilibrium hydrogen concentration in tungsten deposition layer is enormously larger than that in tungsten bulk at same hydrogen pressure.

  5. Spectroscopic and Mechanical Properties of a New Generation of Bulk Fill Composites.

    Monterubbianesi, Riccardo; Orsini, Giovanna; Tosi, Giorgio; Conti, Carla; Librando, Vito; Procaccini, Maurizio; Putignano, Angelo

    2016-01-01

    Objectives: The aims of this study were to in vitro evaluate the degree of conversion and the microhardness properties of five bulk fill resin composites; in addition, the performance of two curing lamps, used for composites polymerization, was also analyzed. Materials and Methods: The following five resin-based bulk fill composites were tested: SureFil SDR®, Fill Up!™, Filtek™, SonicFill™, and SonicFill2™. Samples of 4 mm in thickness were prepared using Teflon molds filled in one increment and light-polymerized using two LED power units. Ten samples for each composite were cured using Elipar S10 and 10 using Demi Ultra. Additional samples of SonicFill2, (3 and 5 mm-thick) were also tested. The degree of conversion (DC) was determined by Raman spectroscopy, while the Vickers microhardness (VMH) was evaluated using a microhardness tester. The experimental evaluation was carried out on top and bottom sides, immediately after curing (t0), and, on bottom, after 24 h (t24). Two-ways analysis of variance was applied to evaluate DC and VMH-values. In all analyses, the level of significance was set at p composites recorded satisfactory DCs on top and bottom sides. At t0, the top of SDR and SonicFill2 showed the highest DCs-values (85.56 ± 9.52 and 85.47 ± 1.90, respectively), when cured using Elipar S10; using Demi Ultra, SonicFill2 showed the highest DCs-values (90.53 ± 2.18). At t0, the highest DCs-values of bottom sides were recorded by SDR (84.64 ± 11.68), when cured using Elipar S10, and Filtek (81.52 ± 4.14), using Demi Ultra. On top sides, Demi Ultra lamp showed significant higher DCs compared to the Elipar S10 ( p composites showed higher VMH than the flowable or dual curing composites.

  6. Long-term stable water vapor permeation barrier properties of SiN/SiCN/SiN nanolaminated multilayers grown by plasma-enhanced chemical vapor deposition at extremely low pressures

    Choi, Bum Ho; Lee, Jong Ho

    2014-01-01

    We investigated the water vapor permeation barrier properties of 30-nm-thick SiN/SiCN/SiN nanolaminated multilayer structures grown by plasma enhanced chemical vapor deposition at 7 mTorr. The derived water vapor transmission rate was 1.12 × 10 −6 g/(m 2 day) at 85 °C and 85% relative humidity, and this value was maintained up to 15 000 h of aging time. The X-ray diffraction patterns revealed that the nanolaminated film was composed of an amorphous phase. A mixed phase was observed upon performing high resolution transmission electron microscope analysis, which indicated that a thermodynamically stable structure was formed. It was revealed amorphous SiN/SiCN/SiN multilayer structures that are free from intermixed interface defects effectively block water vapor permeation into active layer

  7. Effects of seed geometry on the crystal growth and the magnetic properties of single grain REBCO bulk superconductors

    Lee, Hwi Joo; Lee, Hee Gyoun [Korea Polytechnic University, Siheung (Korea, Republic of); Park, Soon Dong; Jun, Bung Hyack; Kim, Chan Joong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2017-09-15

    This study presents that the orientation and the geometry of seed affect on the growth behavior of melt processed single grain REBCO bulk superconductor and its magnetic properties. The effects of seed geometry have been investigated for thin 30mm x 30mm rectangular powder compacts. Single grain REBCO bulk superconductors have been grown successfully by a top seed melt growth method for 8-mm thick vertical thin REBCO slab. Asymmetric structures have been developed at the front surface and at the rear surface of the specimen. Higher magnetic properties have been obtained for the specimen that c-axis is normal to the specimen surface. The relationships between microstructure, grain growth and magnetic properties have been discussed.

  8. The decay properties of the trapped magnetic field in HTS bulk superconducting actuator by AC controlled magnetic field

    Kim, S.B.; Uwani, Y.; Joo, J.H.; Kawamoto, R.; Jo, Y.S.

    2011-01-01

    The electric device applications of a high temperature superconducting (HTS) bulk magnet, having stable levitation and suspension properties according to their strong flux pinning force, have been proposed and developed. We have been investigating a three-dimensional (3-D) superconducting actuator using HTS bulks to develop a non-contract transportation device which moves freely in space. It is certain for our proposed 3-D superconducting actuator to be useful as a transporter used in a clean room where silicon wafers, which do not like mechanical contact and dust, are manufactured. The proposed actuator consists of the trapped HTS bulk as a mover and two-dimensionally arranged electromagnets as a stator. Up to now, the electromagnets consisted with iron core and copper coil were used as a stator, and each electromagnet was individually controlled using DC power supplies. In our previous work, the unstable movement characteristics of HTS bulk were observed under the DC operation, and the AC electromagnets driven with AC controlled current was proposed to solve these problems. In general, the trapped magnetic field in HTS bulk was decayed by a time-varying external magnetic field. Thus, it needs to optimize the shapes of AC electromagnets and operating patterns, the decay properties of the trapped magnetic field in the HTS bulk mover by the AC magnetic field should be cleared. In this paper, the influences of the frequency, the overall operating time, the strength of magnetization field and drive current against the decay of trapped magnetic field were experimentally studied using the fabricated AC electromagnets.

  9. Investigation on properties of ultrafast switching in a bulk gallium arsenide avalanche semiconductor switch

    Hu, Long; Su, Jiancang; Ding, Zhenjie; Hao, Qingsong; Yuan, Xuelin

    2014-01-01

    Properties of ultrafast switching in a bulk gallium arsenide (GaAs) avalanche semiconductor switch based on semi-insulating wafer, triggered by an optical pulse, were analyzed using physics-based numerical simulations. It has been demonstrated that when a voltage with amplitude of 5.2 kV is applied, after an exciting optical pulse with energy of 1 μJ arrival, the structure with thickness of 650 μm reaches a high conductivity state within 110 ps. Carriers are created due to photons absorption, and electrons and holes drift to anode and cathode terminals, respectively. Static ionizing domains appear both at anode and cathode terminals, and create impact-generated carriers which contribute to the formation of electron-hole plasma along entire channel. When the electric field in plasma region increases above the critical value (∼4 kV/cm) at which the electrons drift velocity peaks, a domain comes into being. An increase in carrier concentration due to avalanche multiplication in the domains reduces the domain width and results in the formation of an additional domain as soon as the field outside the domains increases above ∼4 kV/cm. The formation and evolution of multiple powerfully avalanching domains observed in the simulations are the physical reasons of ultrafast switching. The switch exhibits delayed breakdown with the characteristics affected by biased electric field, current density, and optical pulse energy. The dependence of threshold energy of the exciting optical pulse on the biased electric field is discussed

  10. Atomic-scale simulation study of some bulk and interfacial properties of iron aluminium ordered alloys

    Besson, Remy

    1997-01-01

    A semi-empirical potential was designed for B 2 and DO 3 iron aluminides and used to study point defects and grain boundaries in these compounds. At low temperature, departure from B 2 stoichiometry is accommodated with antisite defects; when T increases, iron vacancies appear and defects have a trend to form clusters, the structure of which is very sensitive to this departure. Our calculations, relying on T = 0 K formation energies, predict the nature of major defects, but lead to underestimated quantitative results, which may point out the essential role of atomic vibrations. In the stoichiometric B 2 compound, the diffusion of both species is induced by four-jump cycles involving iron vacancies. Although the agreement between our calculated activation energies and other experiments is good, the calculated diffusion coefficients are below the experimental ones. Here again, this discrepancy may be put down to the overlooking of phonon contributions. The second application concerns the atomic structures of the [001] (310) symmetric tilt grain boundary in the B 2 and DO 3 compounds. At low temperature, in the stoichiometric B 2 compound, we obtain an iron-rich single stable structure (pseudo-symmetric), whose structure is strongly influenced by the bulk composition (with intergranular segregation of the major element). In the stoichiometric DO 3 compound, many energetically equivalent structures exist, all being systematically aluminium-rich. The study of the B 2 grain boundary structure at high temperature shows a phase transition favouring a symmetric structure. Its high excess energy at low temperature emphasizes the influence of atomic vibrations in the interfacial properties of B 2 Fe-Al compounds. (author) [fr

  11. Effect of density increase on self-absorption property of bulk samples

    Dao Anh Minh; Tran Duc Thiep

    1990-01-01

    Asymptotic behaviour due to self-absorption of photon attenuation function in terms of material density for bulk samples has been considered. Some practical applications have also been presented. (author). 9 refs., 4 figs., 2 tabs

  12. Pulsed-Field Magnetization Properties of Bulk Superconductors by Employment of Vortex-Type Coils

    Deng, Z.; Shinohara, N.; Miki, M.; Felder, B.; Tsuzuki, K.; Watasaki, M.; Kawabe, S.; Taguchi, R.; Izumi, M.

    Vortex-type magnetizing coils are gaining more and more attention to activate bulk superconductors in pulsed-field magnetization (PFM) studies, compared with solenoid-type ones. Following existing reports, we present experimental results of the different penetration patterns of magnetic flux between the two kinds of coils. It was found that the magnetic flux will primarily penetrate inside the bulk from the upper and lower surfaces by using vortex coils, rather than from the periphery in the case of solenoid coils. Moreover, the bulk submitted to a small pulsed-field excitation exhibits a similar field profile as the excitation field (convex or concave shape); a phenomenon named field memory effect. The use of vortex- or solenoid-type coils in PFM will pose an influence on the initial flux penetration patterns during the flux trapping processes, but both coils can finally excite the best conical trapped field shape of the bulk.

  13. Effect of silver addition on the mechanical and field trapping properties of Gd-Ba-Cu-O bulk superconductors

    Nariki, S; Matsui, M; Murakami, M

    2002-01-01

    The effect of Ag addition on the microstructure and the mechanical and field trapping properties of Gd-Ba-Cu-O bulk superconductor has been investigated. The single grain Gd-Ba-Cu-O bulk superconductors 32 mm in diameter were fabricated with 0-30 mass%Ag/sub 2/O additions by the melt growth method under controlled oxygen partial pressure of 1.0%. From microscopic observations, it was found that the macro- cracks in the a-b plane decreased with Ag addition. The three-point bending test showed that the average strength of Ag-free bulk was 69 MPa at room temperature, while the strength was dramatically improved to 110-115 MPa with 10-30 mass%Ag/sub 2/O additions. The trapped magnetic field of Ag-free bulk sample was 1.3 T at 77 K. The trapped field of bulk Gd-Ba-Cu-O samples with 10-20 mass%Ag/sub 2/O exhibited high values of 1.8-2.0 T at 77 K. However, the trapped field of the sample with 30 mass%Ag/sub 2/O addition was lowered to 1.1 T with decreasing the critical current density. The trapped field of Ag- adde...

  14. Synthesis and magnetic properties of bulk transparent PMMA/Fe-oxide nanocomposites

    Li, Shanghua; Qin, Jian; Fornara, Andrea; Toprak, Muhammet; Muhammed, Mamoun; Kim, Do Kyung

    2009-05-01

    PMMA/Fe-oxide nanocomposites are fabricated by a chemical method. Monodispersed Fe-oxide nanoparticles are well dispersed in the PMMA matrix by in situ polymerization, resulting in a bulk transparent polymeric nanocomposite. The magnetic behavior of the PMMA/Fe-oxide nanocomposites is investigated. The transparent PMMA/Fe-oxide nanocomposite has potentially interesting magneto-optic applications without compromising the advantages of a lightweight, noncorrosive polymeric material with very high transparency even for bulk samples.

  15. Synthesis and magnetic properties of bulk transparent PMMA/Fe-oxide nanocomposites

    Li Shanghua; Qin Jian; Fornara, Andrea; Toprak, Muhammet; Muhammed, Mamoun; Kim, Do Kyung

    2009-01-01

    PMMA/Fe-oxide nanocomposites are fabricated by a chemical method. Monodispersed Fe-oxide nanoparticles are well dispersed in the PMMA matrix by in situ polymerization, resulting in a bulk transparent polymeric nanocomposite. The magnetic behavior of the PMMA/Fe-oxide nanocomposites is investigated. The transparent PMMA/Fe-oxide nanocomposite has potentially interesting magneto-optic applications without compromising the advantages of a lightweight, noncorrosive polymeric material with very high transparency even for bulk samples.

  16. Counter-diffusion and -permeation of deuterium and hydrogen through metals

    Kizu, Kaname; Tanabe,; Tetsuo, [Nagoya Univ. (Japan)

    1998-03-01

    The first experiments for counter-diffusion and -permeation of deuterium and hydrogen through palladium were performed. Deuterium permeation rates against D{sub 2} pressure were measured under the condition where hydrogen permeated to opposite direction by supplying H{sub 2} gas at the permeated side of D{sub 2}. It was found that not a small amount of deuterium was clearly permeated even if the deuterium pressure was much smaller than the hydrogen pressure. Deuterium permeation rate was gradually reduced by increasing the counter H permeation. The deuterium permeation rate under the counter H permeation is well represented by a simple model in which the ratio of the deuterium permeation rates with and without the counter H permeation was proportional to the fractional concentration of deuterium in the bulk. As increasing the hydrogen counter flow, however, the deuterium permeation rate deviates from the model. This means that adsorption (absorption) of D{sub 2} from gas phase is inhibited and surface recombination of deuterium is blocked by hydrogen. (author)

  17. Nanomechanical properties of thick porous silicon layers grown on p- and p+-type bulk crystalline Si

    Charitidis, C.A.; Skarmoutsou, A.; Nassiopoulou, A.G.; Dragoneas, A.

    2011-01-01

    Highlights: → The nanomechanical properties of bulk crystalline Si. → The nanomechanical properties of porous Si. → The elastic-plastic deformation of porous Si compared to bulk crystalline quantified by nanoindentation data analysis. - Abstract: The nanomechanical properties and the nanoscale deformation of thick porous Si (PSi) layers of two different morphologies, grown electrochemically on p-type and p+-type Si wafers were investigated by the depth-sensing nanoindentation technique over a small range of loads using a Berkovich indenter and were compared with those of bulk crystalline Si. The microstructure of the thick PSi layers was characterized by field emission scanning electron microscopy. PSi layers on p+-type Si show an anisotropic mesoporous structure with straight vertical pores of diameter in the range of 30-50 nm, while those on p-type Si show a sponge like mesoporous structure. The effect of the microstructure on the mechanical properties of the layers is discussed. It is shown that the hardness and Young's modulus of the PSi layers exhibit a strong dependence on their microstructure. In particular, PSi layers with the anisotropic straight vertical pores show higher hardness and elastic modulus values than sponge-like layers. However, sponge-like PSi layers reveal less plastic deformation and higher wear resistance compared with layers with straight vertical pores.

  18. Bulk properties of the medium produced in relativistic heavy-ion collisions from the beam energy scan program

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Ajitanand, N. N.; Alekseev, I.; Anderson, D. M.; Aoyama, R.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Ashraf, M. U.; Attri, A.; Averichev, G. S.; Bai, X.; Bairathi, V.; Behera, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, J. D.; Brandin, A. V.; Brown, D.; Bunzarov, I.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chankova-Bunzarova, N.; Chatterjee, A.; Chattopadhyay, S.; Chen, X.; Chen, J. H.; Chen, X.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Elsey, N.; Engelage, J.; Eppley, G.; Esha, R.; Esumi, S.; Evdokimov, O.; Ewigleben, J.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Federicova, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Finch, E.; Fisyak, Y.; Flores, C. E.; Fulek, L.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Gupta, S.; Guryn, W.; Hamad, A. I.; Hamed, A.; Harlenderova, A.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Horvat, S.; Huang, T.; Huang, B.; Huang, X.; Huang, H. Z.; Humanic, T. J.; Huo, P.; Igo, G.; Jacobs, W. W.; Jentsch, A.; Jia, J.; Jiang, K.; Jowzaee, S.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z.; Kikoła, D. P.; Kisel, I.; Kisiel, A.; Kochenda, L.; Kocmanek, M.; Kollegger, T.; Kosarzewski, L. K.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulathunga, N.; Kumar, L.; Kvapil, J.; Kwasizur, J. H.; Lacey, R.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, X.; Li, C.; Li, W.; Li, Y.; Lidrych, J.; Lin, T.; Lisa, M. A.; Liu, H.; Liu, P.; Liu, Y.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, S.; Luo, X.; Ma, G. L.; Ma, L.; Ma, Y. G.; Ma, R.; Magdy, N.; Majka, R.; Mallick, D.; Margetis, S.; Markert, C.; Matis, H. S.; Meehan, K.; Mei, J. C.; Miller, Z. W.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mizuno, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nasim, Md.; Nayak, T. K.; Nelson, J. M.; Nie, M.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Nonaka, T.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V. A.; Olvitt, D.; Page, B. S.; Pak, R.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Pile, P.; Pluta, J.; Poniatowska, K.; Porter, J.; Posik, M.; Poskanzer, A. M.; Pruthi, N. K.; Przybycien, M.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Ray, R. L.; Reed, R.; Rehbein, M. J.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roth, J. D.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Salur, S.; Sandweiss, J.; Saur, M.; Schambach, J.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Schweid, B. R.; Seger, J.; Sergeeva, M.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, A.; Sharma, M. K.; Shen, W. Q.; Shi, Z.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Singha, S.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Solyst, W.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Strikhanov, M.; Stringfellow, B.; Sugiura, T.; Sumbera, M.; Summa, B.; Sun, Y.; Sun, X. M.; Sun, X.; Surrow, B.; Svirida, D. N.; Tang, A. H.; Tang, Z.; Taranenko, A.; Tarnowsky, T.; Tawfik, A.; Thäder, J.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Todoroki, T.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Trzeciak, B. A.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vasiliev, A. N.; Videbæk, F.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, G.; Wang, Y.; Wang, F.; Wang, Y.; Webb, J. C.; Webb, G.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xiao, Z. G.; Xie, W.; Xie, G.; Xu, J.; Xu, N.; Xu, Q. H.; Xu, Y. F.; Xu, Z.; Yang, Y.; Yang, Q.; Yang, C.; Yang, S.; Ye, Z.; Ye, Z.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, Z.; Zhang, X. P.; Zhang, J. B.; Zhang, S.; Zhang, J.; Zhang, Y.; Zhang, J.; Zhang, S.; Zhao, J.; Zhong, C.; Zhou, L.; Zhou, C.; Zhu, X.; Zhu, Z.; Zyzak, M.; STAR Collaboration

    2017-10-01

    We present measurements of bulk properties of the matter produced in Au+Au collisions at √{sN N}=7.7 ,11.5 ,19.6 ,27 , and 39 GeV using identified hadrons (π±, K±, p , and p ¯) from the STAR experiment in the Beam Energy Scan (BES) Program at the Relativistic Heavy Ion Collider (RHIC). Midrapidity (|y |<0.1 ) results for multiplicity densities d N /d y , average transverse momenta 〈pT〉 , and particle ratios are presented. The chemical and kinetic freeze-out dynamics at these energies are discussed and presented as a function of collision centrality and energy. These results constitute the systematic measurements of bulk properties of matter formed in heavy-ion collisions over a broad range of energy (or baryon chemical potential) at RHIC.

  19. The impact of compaction, moisture content, particle size and type of bulking agent on initial physical properties of sludge-bulking agent mixtures before composting.

    Huet, J; Druilhe, C; Trémier, A; Benoist, J C; Debenest, G

    2012-06-01

    This study aimed to experimentally acquire evolution profiles between depth, bulk density, Free Air Space (FAS), air permeability and thermal conductivity in initial composting materials. The impact of two different moisture content, two particle size and two types of bulking agent on these four parameters was also evaluated. Bulk density and thermal conductivity both increased with depth while FAS and air permeability both decreased with it. Moreover, depth and moisture content had a significant impact on almost all the four physical parameters contrary to particle size and the type of bulking agent. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Free volume and elastic properties changes in Cu-Zr-Ti-Pd bulk glassy alloy on heating

    Louzguine-Luzgin, Dmitri V.; Yavari, Alain Reza; Fukuhara, Mikio; Ota, Katsumi; Xie, Guoqiang; Vaughan, Gavin; Inoue, Akihisa

    2007-01-01

    The variation of free volume and elastic properties of the Cu 55 Zr 30 Ti 10 Pd 5 glassy alloy on heating was studied. The structure changes on heating were studied by synchrotron X-ray diffraction, differential scanning and isothermal calorimetries. The studied glassy alloy shows a rather high Poisson's ratio exceeding 0.42 which is maintained after the structure relaxation and primary devitrification. Young's and Shear modules decrease upon primary devitrification while Bulk modulus exhibits a maximum after structural relaxation

  1. Influence of various irradiation processes on the mechanical properties and polymerisation kinetics of bulk-fill resin based composites.

    Ilie, Nicoleta; Keßler, Andreas; Durner, Jürgen

    2013-08-01

    To assess the effect of irradiation time and distance of the light tip on the micro-mechanical properties and polymerisation kinetics of two bulk-fill resin-based composites at simulated clinically relevant filling depth. Micro-mechanical properties (Vickers hardness (HV), depth of cure (DOC) and indentation modulus (E)) and polymerisation kinetics (real-time increase of degree of cure (DC)) of two bulk-fill resin-based composites (Tetric EvoCeram(®) Bulk Fill, Ivoclar Vivadent and x-tra base, Voco) were assessed at varying depth (0.1-6mm in 100μm steps for E and HV and 0.1, 2, 4 and 6mm for DC), irradiation time (10, 20 or 40s, Elipar Freelight2) and distances from the light tip (0 and 7mm). Curing unit's irradiance was monitored in 1mm steps at distances up to 10mm away from the light tip on a laboratory-grade spectrometer. Multivariate analysis (α=0.05), Student's t-test and Pearson correlation analysis were considered. The influence of material on the measured mechanical properties was significant (η(2)=0.080 for E and 0.256 for HV), while the parameters irradiation time, distance from the light tip and depth emphasise a stronger influence on Tetric EvoCeram(®) Bulk Fill. The polymerisation kinetics could be described by an exponential sum function, distinguishing between the gel and the glass phase. The above mentioned parameters strongly influenced the start of polymerisation (gel phase), and were of less importance for the glass phase. Both materials enable at least 4mm thick increments to be cured in one step under clinically relevant curing conditions. The susceptibility to variation in irradiance was material dependent, thus properties measured under clinically simulated curing conditions might vary to a different extent from those measured under ideal curing conditions. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Permeation barrier for lightweight liquid hydrogen tanks

    Schultheiss, D.

    2007-04-16

    For the future usage of hydrogen as an automotive fuel, its on-board storage is crucial. One approach is the storage of liquid hydrogen (LH2, 20 K) in double-walled, vacuum insulated tanks. The introduction of carbon fiber reinforced plastics (CFRP) as structural material enables a high potential of reducing the weight in comparison to the state-of-the-art stainless steel tanks. The generally high permeability of hydrogen through plastics, however, can lead to long-term degradation of the insulating vacuum. The derived objective of this dissertation was to find and apply an adequate permeation barrier (liner) on CFRP. The investigated liners were either foils adhered on CFRP specimens or coatings deposited on CFRP specimens. The coatings were produced by means of thermal spraying, metal plating or physical vapor deposition (PVD). The materials of the liners included Al, Au, Cu, Ni and Sn as well as stainless steel and diamond-like carbon. The produced liners were tested for their permeation behavior, thermal shock resistance and adherence to the CFRP substrate. Additionally, SEM micrographs were used to characterize and qualify the liners. The foils, although being a good permeation barrier, adhered weakly to the substrate. Furthermore, leak-free joining of foil segments is a challenge still to be solved. The metal plating liners exhibited the best properties. For instance, no permeation could be detected through a 50 {mu}m thick Cu coating within the accuracy of the measuring apparatus. This corresponds to a reduction of the permeation gas flow by more than factor 7400 compared to uncoated CFRP. In addition, the metal platings revealed a high adherence and thermal shock resistance. The coatings produced by means of thermal spraying and PVD did not show a sufficient permeation barrier effect. After having investigated the specimens, a 170 liter CFRP tank was fully coated with 50 {mu}m Cu by means of metal plating. (orig.)

  3. Correlation of Bulk Dielectric and Piezoelectric Properties to the Local Scale Phase Transformations, Domain Morphology, and Crystal Structure Modified

    Priya, Shashank [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Viehland, Dwight [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

    2014-12-14

    Three year program entitled “Correlation of bulk dielectric and piezoelectric properties to the local scale phase transformations, domain morphology, and crystal structure in modified lead-free grain-textured ceramics and single crystals” was supported by the Department of Energy. This was a joint research program between D. Viehland and S. Priya at Virginia Tech. Single crystal and textured ceramics have been synthesized and characterized. Our goals have been (i) to conduct investigations of lead-free piezoelectric systems to establish the local structural and domain morphologies that result in enhanced properties, and (ii) to synthesize polycrystalline and grain oriented ceramics for understanding the role of composition, microstructure, and anisotropy

  4. Photothermal Infrared Radiometry in Experimental Studies of the Pyroelectric Properties of Bulk Materials

    Aleksandrov, S. E.; Gavrilov, G. A.; Kapralov, A. A.; Muratikov, K. L.; Sotnikova, G. Yu.

    2017-12-01

    A simple and efficient method for determining the pyrolelectric coefficients of ferroelectric and pyroelectric bulk materials by taking into account the heat exchange of a sample with the environment is proposed on the basis of the radiometric registration of the variation dynamics of the temperature of the surface when it is exposed to laser radiation in the form of a temporal step.

  5. Particle models for discrete element modeling of bulk grain properties of wheat kernels

    Recent research has shown the potential of discrete element method (DEM) in simulating grain flow in bulk handling systems. Research has also revealed that simulation of grain flow with DEM requires establishment of appropriate particle models for each grain type. This research completes the three-p...

  6. Structure and property evaluation of a vacuum plasma sprayed nanostructured tungsten-hafnium carbide bulk composite

    Rea, K. E.; Viswanathan, V.; Kruize, A.; De Hosson, J. Th. M.; O'Dell, S.; McKechnie, T.; Rajagopalan, S.; Vaidyanathan, R.; Seal, S.; O’Dell, S.

    2008-01-01

    Vacuum plasma spray (VPS) forming of tungsten-based metal matrix nanocomposites (MMCs) has shown to be a cost effective and time saving method for the formation of bulk monolithic nanostructured then no-mechanical components. Spray drying of powder feedstock appears to have a significant effect on

  7. The effect of Sm addition on the microstructure and superconducting properties of YBCO bulk superconductors

    Volochová, D.; Diko, P.; Piovarči, S.; Antal, V.; Kováč, J.; Jirsa, Miloš

    2017-01-01

    Roč. 131, č. 4 (2017), s. 1009-1011 ISSN 0587-4246 Institutional support: RVO:68378271 Keywords : YBaCuO * bulk superconductors * paramagnetic ions * microstructure * vortex pinning Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 0.469, year: 2016

  8. Tuning Optoelectronic Properties of Ambipolar Organic Light-Emitting Transistors Using a Bulk-Heterojunction Approach

    Loi, Maria Antonietta; Rost-Bietsch, Constance; Murgia, Mauro; Karg, Siegfried; Riess, Walter; Muccini, Michele

    2006-01-01

    Bulk-heterojunction engineering is demonstrated as an approach to producing ambipolar organic light-emitting field-effect transistors with tunable electrical and optoelectronic characteristics. The electron and hole mobilities, as well as the electroluminescence intensity, can be tuned over a large

  9. Influence of the polymer architecture on morphology and device properties of polymer bulk heterojunction photovoltaic cells

    Koetse, M.M.; Sweelssen, J.; Franse, T.; Veenstra, S.C.; Kroon, J.M.; Yang, X.N.; Alexeev, A.A.; Loos, J.; Schubert, U.S.; Schoo, H.F.M.; Kafafi, Z.H.; Lane, P.A.

    2004-01-01

    Polymer bulk hetero junction solar cells were made from poly(2-methoxy-5-(3,7-dimethyloctyloxy)-1,4-phenylene-vinylene) (MDMO-PPV) as donor and poly(cyanoetherphenylenevinylene) (PCNEPV) derivatives as acceptor material. In this paper we start out with discussing the synthesis of the materials.

  10. Comparing Classical Water Models Using Molecular Dynamics to Find Bulk Properties

    Kinnaman, Laura J.; Roller, Rachel M.; Miller, Carrie S.

    2018-01-01

    A computational chemistry exercise for the undergraduate physical chemistry laboratory is described. In this exercise, students use the molecular dynamics package Amber to generate trajectories of bulk liquid water for 4 different water models (TIP3P, OPC, SPC/E, and TIP4Pew). Students then process the trajectory to calculate structural (radial…

  11. Permeation of aromatic solvent mixtures through nitrile protective gloves.

    Chao, Keh-Ping; Hsu, Ya-Ping; Chen, Su-Yi

    2008-05-30

    The permeation of binary and ternary mixtures of benzene, toluene, ethyl benzene and p-xylene through nitrile gloves were investigated using the ASTM F739 test cell. The more slowly permeating component of a mixture was accelerated to have a shorter breakthrough time than its pure form. The larger differences in solubility parameter between a solvent mixture and glove resulted in a lower permeation rate. Solubility parameter theory provides a potential approach to interpret the changes of permeation properties for BTEX mixtures through nitrile gloves. Using a one-dimensional diffusion model based on Fick's law, the permeation concentrations of ASTM F739 experiments were appropriately simulated by the estimated diffusion coefficient and solubility. This study will be a fundamental work for the risk assessment of the potential dermal exposure of workers wearing protective gloves.

  12. A comparative study on optical and magnetic resonance properties of near-surface NV centers in nano and bulk diamond

    Frederico Brandao

    2014-01-01

    Using shallow nitrogen-vacancy (NV) centers in diamond for applications in magnetometry requires the generation of stable defects in the NV charge state in sufficiently high density and high quality spin properties. Recent studies reported about NV defects close to the surface created by ion implantation or during chemical vapor deposition growth technique and in nanodiamonds point to a scenario where defects are stabilized in the neutral charge state and that the minority of negatively charged state defects have poor spin properties, i.e.g shorter coherence times compared to NV defects deeply localized in bulk diamond. This undesirable behavior appears to result from the interaction with rapidly fluctuating electric fields created by moving charges at the surface and with interface effects associated with the termination of the diamond surface. Here we report studies of photoluminescence and magnetic resonance properties of shallow NV ensembles created by low energy nitrogen ion implantation in electronic grade diamond substrate and nanodiamonds with low nitrogen concentration. We verified the shallow NV center spin properties through pulsed optically detected magnetic resonance (ODMR) protocols and found longitudinal time constant (T1) of a few milliseconds and transversal relaxation time constant (T2) of a few microseconds for shallow defects implanted in bulk diamond. For nanodiamonds, the T2 coherence time is similar to the case in bulk sample but on the other hand the T1 coherence time is ten times shorter than in bulk. Additionally was found the T2* is around one microsecond for shallow NV defects in bulk samples meanwhile in nanodiamonds it is around twenty nanoseconds. It worth to mention that all the measurements were performed in NV ensembles which show just two ODMR resonance lines with applied magnetic field as if they were magnetically equivalent. In that sense we are trying to apply chirped pulses and Ramsey pulse sequence to check this assumption

  13. Electrochemical Characteristics of Layered Transition Metal Oxide Cathode Materials for Lithium Ion Batteries: Surface, Bulk Behavior, and Thermal Properties.

    Tian, Chixia; Lin, Feng; Doeff, Marca M

    2018-01-16

    Layered lithium transition metal oxides, in particular, NMCs (LiNi x Co y Mn z O 2 ) represent a family of prominent lithium ion battery cathode materials with the potential to increase energy densities and lifetime, reduce costs, and improve safety for electric vehicles and grid storage. Our work has focused on various strategies to improve performance and to understand the limitations to these strategies, which include altering compositions, utilizing cation substitutions, and charging to higher than usual potentials in cells. Understanding the effects of these strategies on surface and bulk behavior and correlating structure-performance relationships advance our understanding of NMC materials. This also provides information relevant to the efficacy of various approaches toward ensuring reliable operation of these materials in batteries intended for demanding traction and grid storage applications. In this Account, we start by comparing NMCs to the isostructural LiCoO 2 cathode, which is widely used in consumer batteries. Effects of changing the metal content (Ni, Mn, Co) upon structure and performance of NMCs are briefly discussed. Our early work on the effects of partial substitution of Al, Fe, and Ti for Co on the electrochemical and bulk structural properties is then covered. The original aim of this work was to reduce the Co content (and thus the raw materials cost) and to determine the effect of the substitutions on the electrochemical and bulk structural properties. More recently, we have turned to the application of synchrotron and advanced microscopy techniques to understand both bulk and surface characteristics of the NMCs. Via nanoscale-to-macroscale spectroscopy and atomically resolved imaging techniques, we were able to determine that the surfaces of NMC undergo heterogeneous reconstruction from a layered structure to rock salt under a variety of conditions. Interestingly, formation of rock salt also occurs under abuse conditions. The surface

  14. Photoelectric Properties of Silicon Nanocrystals/P3HT Bulk-Heterojunction Ordered in Titanium Dioxide Nanotube Arrays

    Švrček Vladimir

    2009-01-01

    Full Text Available Abstract A silicon nanocrystals (Si-ncs conjugated-polymer-based bulk-heterojunction represents a promising approach for low-cost hybrid solar cells. In this contribution, the bulk-heterojunction is based on Si-ncs prepared by electrochemical etching and poly(3-hexylthiophene (P3HT polymer. Photoelectric properties in parallel and vertical device-like configuration were investigated. Electronic interaction between the polymer and surfactant-free Si-ncs is achieved. Temperature-dependent photoluminescence and transport properties were studied and the ratio between the photo- and dark-conductivity of 1.7 was achieved at ambient conditions. Furthermore the porous titanium dioxide (TiO2 nanotubes’ template was used for vertical order of photosensitive Si-ncs/P3HT-based blend. The anodization of titanium foil in ethylene glycol-based electrolyte containing fluoride ions and subsequent thermal annealing were used to prepare anatase TiO2nanotube arrays. The arrays with nanotube inner diameter of 90 and 50 nm were used for vertical ordering of the Si-ncs/P3HT bulk-heterojunction.

  15. Silicene-terminated surface of calcium and strontium disilicides: properties and comparison with bulk structures by computational methods

    Brázda, Petr; Mutombo, Pingo; Ondráček, Martin; Corrêa, Cinthia Antunes; Kopeček, Jaromír; Palatinus, Lukáš

    2018-05-01

    The bulk and surface structures of calcium and strontium disilicides are investigated by computational methods using density functional theory. The investigated structures are R6, R3 and P1-CaSi2 and P1-SrSi2. The investigated properties are the cleavage energy at the silicene sheet, buckling of the bulk and surface silicene layers, charge transfer from calcium to silicon, band structure of bulk and surface-terminated structures and adsorption energies on H atoms and H2 molecules on the silicene-terminated surface of the R3 phase. The cleavage energy at the silicene surface is low in all cases. Structures P1-CaSi2 and R3-CaSi2 contain silicene sheets with different coordination to Ca, while R6-CaSi2 contains both types of the sheets. It is shown that the properties of the two types of silicene-like sheets in R6-CaSi2 are similar to those of the corresponding sheets in P1-CaSi2 and R3-CaSi2, and the thermodynamically stable R6 phase is a good candidate for experimental investigation of silicene-terminated surface in calcium disilicide.

  16. Mechanical and bulk properties of intact rock collected in the laboratory in support of the Yucca Mountain Site Characterization Project

    Price, R.H.; Martin, R.J. III; Boyd, P.J.; Boinott, G.N.

    1994-01-01

    A comprehensive laboratory investigation is determining the mechanical properties of tuffs for the Yucca Mountain Site Characterization Project (YMP). Most recently, experiments have been performed on tuff samples from a series of drill holes along the planned alignment of the Exploratory Study Facilities (ESF) north ramp. Unconfined compression and indirect tension experiments were performed and the results are being analyzed with the help of bulk property information. The results on samples from eight of the drill holes are presented. In general, the properties vary widely, but are highly dependent on the sample porosity. The developed relationships between mechanical properties and porosity are powerful tools in the effort to model the rock mass response of Yucca Mountain to the emplacement of the potential high-level radioactive waste repository

  17. Roles of Bulk and Surface Chemistry in the Oxygen Exchange Kinetics and Related Properties of Mixed Conducting Perovskite Oxide Electrodes

    Nicola H. Perry

    2016-10-01

    Full Text Available Mixed conducting perovskite oxides and related structures serving as electrodes for electrochemical oxygen incorporation and evolution in solid oxide fuel and electrolysis cells, respectively, play a significant role in determining the cell efficiency and lifetime. Desired improvements in catalytic activity for rapid surface oxygen exchange, fast bulk transport (electronic and ionic, and thermo-chemo-mechanical stability of oxygen electrodes will require increased understanding of the impact of both bulk and surface chemistry on these properties. This review highlights selected work at the International Institute for Carbon-Neutral Energy Research (I2CNER, Kyushu University, set in the context of work in the broader community, aiming to characterize and understand relationships between bulk and surface composition and oxygen electrode performance. Insights into aspects of bulk point defect chemistry, electronic structure, crystal structure, and cation choice that impact carrier concentrations and mobilities, surface exchange kinetics, and chemical expansion coefficients are emerging. At the same time, an understanding of the relationship between bulk and surface chemistry is being developed that may assist design of electrodes with more robust surface chemistries, e.g., impurity tolerance or limited surface segregation. Ion scattering techniques (e.g., secondary ion mass spectrometry, SIMS, or low energy ion scattering spectroscopy, LEIS with high surface sensitivity and increasing lateral resolution are proving useful for measuring surface exchange kinetics, diffusivity, and corresponding outer monolayer chemistry of electrodes exposed to typical operating conditions. Beyond consideration of chemical composition, the use of strain and/or a high density of active interfaces also show promise for enhancing performance.

  18. Process parameters, orientation, and functional properties of melt-processed bulk Y-Ba-Cu-O superconductors

    Zakharchenko, I.V.; Terryll, K.M.; Rao, K.V.; Balachandran, U.

    1995-03-01

    This study compared the microstructure, texturing, and functional properties (critical currents) of YBa 2 Cu 3 O 7-x -based bulk pellets that were prepared by the quench-melt-growth-process (QMGP), melt-textured growth (MTG), and conventional solid-state reaction (SSR) approaches. Using two X-ray diffraction (XRD) methods, θ-2θ, and rocking curves, the authors found that the individual grains of two melt-processed pellets exhibited remarkable preferred orientational alignment (best rocking curve width = 3.2 degree). However, the direction of the preferred orientation among the grains was random. Among the three types of bulk materials studied, the QMGP sample was found to have the best J c values, ∼ 4,500 A/cm 2 at 77 K in a field of 2 kG, as determined from SQUID magnetic data

  19. Effect of Ge addition on mechanical properties and fracture behavior of Cu-Zr-Al bulk metallic glass

    Malekan, M.; Shabestari, S.G.; Gholamipour, R.; Seyedein, S.H.

    2009-01-01

    Effect of the addition of a small amount of Ge on mechanical properties and fracture behavior of Cu 50 Zr 43 Al 7 (at.%) bulk metallic glass were studied. The Cu 50 Zr 43 Al 7 alloy has a surprising glass-forming ability (GFA), and the glassy rods up to 4 mm in diameter can be formed. Partial addition of Ge causes the crystalline phases precipitate in the glassy matrix of (Cu 50 Zr 43 Al 7 ) 100-x Ge x (x = 0, 1, 2) rods with a diameter of 4 mm. In uniaxial compression, Cu 50 Zr 43 Al 7 bulk metallic glass exhibit high strength of 1692 MPa and very limited plasticity of 0.05%. When Ge increases from 0 to 2 at.%, the strength decreases, but plastic strain increases about 2.5%. Fracture surface and shear bands of samples were investigated by scanning electron microscopy (SEM).

  20. Synthesis of formamidinium lead iodide perovskite bulk single crystal and its optical properties

    Zheng, Hongge; Duan, Junjie; Dai, Jun

    2017-07-01

    Formamidinium lead iodide (FAPbI3) is a promising hybrid perovskite material for optoelectronic devices. We synthesized bulk single crystal FAPbI3 by a rapid solution crystallization method. X-ray diffraction (XRD) was performed to characterize the crystal structure. Temperature-dependent photoluminescence (PL) spectra of the bulk single crystal FAPbI3 were measured from 10 to 300 K to explain PL recombination mechanism. It shows that near band edge emission blueshifts with the temperature increasing from 10 to 120 K and from 140 K to room temperature, a sudden emission band redshift demonstrates near 140 K because of the phase transition from orthorhombic phase to cubic phase. From the temperature-dependent PL spectra, the temperature coefficients of the bandgap and thermal activation energies of FAPbI3 perovskite are fitted.

  1. Preparation and Properties of Mg-Cu-Y-Al bulk Amorphous Alloys

    Pryds, Nini; Eldrup, Morten Mostgaard; Ohnuma, M.

    2000-01-01

    Bulk amorphous (Mg(1-gamma)Al(gamma))(60)CU(30)Y(10) alloys were prepared using a relatively simple technique of rapid cooling of the melt in a copper wedge mould. The temperature vs, time was recorded during the cooling and solidification process of the melt and compared with a spacial and tempo......Bulk amorphous (Mg(1-gamma)Al(gamma))(60)CU(30)Y(10) alloys were prepared using a relatively simple technique of rapid cooling of the melt in a copper wedge mould. The temperature vs, time was recorded during the cooling and solidification process of the melt and compared with a spacial...... temperatures in specimens containing a few percent Al. The alloy with no Al crystallises apparently without the formation of nanoparticles. The critical cooling rate for the formation of an amorphous Mg(60)CU(30)Y(10) specimen was determined experimentally by a combination of DSC data and temperature vs, time...

  2. Glass Formation, Chemical Properties and Surface Analysis of Cu-Based Bulk Metallic Glasses

    Akihisa Inoue

    2011-04-01

    Full Text Available This paper reviews the influence of alloying elements Mo, Nb, Ta and Ni on glass formation and corrosion resistance of Cu-based bulk metallic glasses (BMGs. In order to obtain basic knowledge for application to the industry, corrosion resistance of the Cu–Hf–Ti–(Mo, Nb, Ta, Ni and Cu–Zr–Ag–Al–(Nb bulk glassy alloy systems in various solutions are reported in this work. Moreover, X-ray photoelectron spectroscopy (XPS analysis is performed to clarify the surface-related chemical characteristics of the alloy before and after immersion in the solutions; this has lead to a better understanding of the correlation between the surface composition and the corrosion resistance.

  3. Composition-microstructure-property relationships in dual phase bulk magnetoelectric composite

    Islam, Rashed Adnan

    The coexistence of coupled electrical and magnetic properties in the "magnetoelectric" material has led to the possibility of developing smarter and smaller electronic components. In order to make this possibility a reality, significant efforts are required to understand the science of magnetoelectric (ME) behavior and apply this understanding to develop higher sensitivity material. The primary aims of this thesis are to identify the role of composition, microstructural variables, composite geometry, texturing, post sintering heat treatment, and nanoscale assembly on ME coefficient. The overall objective is to synthesize, characterize and utilize a high ME coefficient composite. The desired range of ME coefficient in the sintered composite is more than 1.5 V/cm.Oe. At first, a piezoelectric composition in the system of Pb(Zr,Ti)O 3 - Pb[(Zn,Ni)1/3Nb2/3]O3 was designed and synthesized which has high energy density (d.g) parameter of 18456.2 x 10-15m2/N and high g constant of 83.1 V-m/N in order to use it as the matrix in piezoelectric---magnetostrictive composite. Secondly it was found that soft piezoelectric phase shows much better magnetoelectric response. The magnetoelectric coefficient for Pb(Zr 0.52Ti0.48)O3 - 15% Pb(Zn1/3Nb 2/3)O3 [PZT - 15 PZN] - 20% Ni0.8Zn 0.2Fe2O4 was found to be around 186 mV/cm.Oe. Thridly, soft magnetic phase with lower coercivity and higher magnetization was found to be suitable for high ME coefficient. Zinc doped Ni-ferrite has higher resistivity, permeability, magnetization and it was found that with increasing Zn concentration the ME coefficient increases exhibiting maxima near 30 at% Zn (138 mV/cm.Oe). Fourthly, if the connectivity was changed from (0-3) to (2-2) which is a bilayer geometry, improved piezoelectric (d33 ˜ 80 pC/N), ferroelectric (polarization = 60 muC/cm2), magnetization (25 emu/gm) and lower coercive field (2.8 Oe) were measured. The bilayer shows an enhancement of 67% increase in ME coefficient compared to bulk

  4. Investigation of optical properties and electronic transitions in bulk and nano-microribbons of molybdenum trioxide

    Lupan, O; Mishra, Y K; Adelung, R; Trofim, V; Cretu, V; Stamov, I; Syrbu, N N; Tiginyanu, I

    2014-01-01

    In this work, we report on crystalline quality and optical characteristics of molybdenum trioxide (MoO 3 ) bulk and nano-microribbons grown by rapid thermal oxidation (RTO). The developed RTO procedure allows one to synthesize highly crystalline (α-phase) bulk and nano-microribbons of MoO 3 . For R–Γ indirect transitions in bulk single crystals of MoO 3 , it has been found that the width of the bandgap along the E‖c polarization, associated with transitions R v1 –Γ c1 , is lower than the width of the band gap in polarization E ⊥ c, associated with transitions R v2 –Γ c2 . This result is indicative of splitting of the absorption edge due to α-MoO 3 structural anisotropy. Studies of the polarization dependence of the absorption in nano-microribbons (d ≈ 15–500 nm) demonstrated that the energy gap corresponding to R v1 –X c1 (E‖c) transition is smaller than that of R v2 –X c2 (E ⊥ c) transition. Similar dependence has been found for the R–Y indirect transitions. The results of the investigation of the reflectance spectra in the energy range from 3 to 6 eV are shown. By using the Kramers–Kronig method, the optical functions were derived from the reflection spectra of nano-microribbons, and the polarization dependence of direct energy transitions at the point R in the Brillouin zone are determined. The alternation in splitting caused by polarization of the absorption edge related to indirect transitions due to polarization opens new prospects for the design and fabricating interesting optoelectronic devices based on α-MoO 3 bulk and nano-microribbons with characteristics dependent on the polarization of light waves. (paper)

  5. Effect of preheating and light-curing unit on physicochemical properties of a bulk fill composite

    Theobaldo JD

    2017-05-01

    Full Text Available Jéssica Dias Theobaldo,1 Flávio Henrique Baggio Aguiar,1 Núbia Inocencya Pavesi Pini,2 Débora Alves Nunes Leite Lima,1 Priscila Christiane Suzy Liporoni,3 Anderson Catelan3 1Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas, Piracicaba, 2Ingá University Center, Maringá, 3Departament of Dentistry, University of Taubaté, Taubaté, Brazil Objective: The aim of this study is to evaluate the effect of composite preheating and polymerization mode on degree of conversion (DC, microhardness (KHN, plasticization (P, and depth of polymerization (DP of a bulk fill composite.Methods: Forty disc-shaped samples (n = 5 of a bulk fill composite were prepared (5 × 4 mm thick and randomly divided into 4 groups according to light-curing unit (quartz–tungsten–halogen [QTH] or light-emitting diode [LED] and preheating temperature (23 or 54 °C. A control group was prepared with a flowable composite at room temperature. DC was determined using a Fourier transform infrared spectrometer, KHN was measured with a Knoop indenter, P was evaluated by percentage reduction of hardness after 24 h of ethanol storage, and DP was obtained by bottom/top ratio. Data were statistically analyzed by analysis of variance and Tukey’s test (α = 0.05.Results: Regardless of light-curing, the highest preheating temperature increased DC compared to room temperature on bottom surface. LED showed a higher DC compared to QTH. Overall, DC was higher on top surface than bottom. KHN, P, and DP were not affected by curing mode and temperature, and flowable composite showed similar KHN, and lower DC and P, compared to bulk fill.Conclusion: Composite preheating increased the polymerization degree of 4-mm-increment bulk fill, but it led to a higher plasticization compared to the conventional flowable composite evaluated. Keywords: composite resins, physicochemical phenomena, polymerization, hardness, heating

  6. The microstructure of MX-80 clay with respect to its bulk physical properties under different environmental conditions

    Pusch, R. [Geodevelopment AB, Lund (Sweden)

    2001-03-01

    A model of microstructural evolution of MX-80 buffer is presented in the report.Quantification of the microstructure is made by use of digitalized micrographs taken by transmission electron microscopy using suitably impregnated specimens with appropriate thickness. The model is termed MMM, a successor of the earlier GMM. Practically useful microstructural parameters refer to the fraction of a thin section that represents dense and soft parts of the clay matrix. The derived microstructural parameters are directly coupled to the most important bulk physical properties, i.e. the hydraulic conductivity, gas penetrability, swelling pressure and cation/anion diffusion capacities. The study has shown that even at very high densities, softer and more pervious zones exist in the form of interconnected 'external' voids filled with more or less dense clay gels. At bulk densities exceeding 2000 kg/m{sup 3} after water saturation, the gel density is also high but for low bulk densities it may be so much reduced that the gels do not remain stable at high electrolyte content of the pore water. The fact that the density variations are small for high bulk densities means that the separation of matrix components ('fracturing') that is required for letting gas through is on the same order of magnitude as the bulk swelling pressure. For lower bulk densities, displacement or consolidation of the clay gels in 'external' voids is concluded to take place in conjunction with gas penetration. At high densities the limited degree of continuity and constrictions of the channels leading to anion-excluding charge conditions mean that the anion diffusion capacity is very low, while cation diffusion may be extensive because it takes place not only through channels but also through the inter lamellar space and along the surfaces of stacks of lamellae, i.e. by surface diffusion. Two Pre-Quaternary clays that have been investigated and characterized with respect to the

  7. The microstructure of MX-80 clay with respect to its bulk physical properties under different environmental conditions

    Pusch, R.

    2001-03-01

    A model of microstructural evolution of MX-80 buffer is presented in the report.Quantification of the microstructure is made by use of digitalized micrographs taken by transmission electron microscopy using suitably impregnated specimens with appropriate thickness. The model is termed MMM, a successor of the earlier GMM. Practically useful microstructural parameters refer to the fraction of a thin section that represents dense and soft parts of the clay matrix. The derived microstructural parameters are directly coupled to the most important bulk physical properties, i.e. the hydraulic conductivity, gas penetrability, swelling pressure and cation/anion diffusion capacities. The study has shown that even at very high densities, softer and more pervious zones exist in the form of interconnected 'external' voids filled with more or less dense clay gels. At bulk densities exceeding 2000 kg/m 3 after water saturation, the gel density is also high but for low bulk densities it may be so much reduced that the gels do not remain stable at high electrolyte content of the pore water. The fact that the density variations are small for high bulk densities means that the separation of matrix components ('fracturing') that is required for letting gas through is on the same order of magnitude as the bulk swelling pressure. For lower bulk densities, displacement or consolidation of the clay gels in 'external' voids is concluded to take place in conjunction with gas penetration. At high densities the limited degree of continuity and constrictions of the channels leading to anion-excluding charge conditions mean that the anion diffusion capacity is very low, while cation diffusion may be extensive because it takes place not only through channels but also through the inter lamellar space and along the surfaces of stacks of lamellae, i.e. by surface diffusion. Two Pre-Quaternary clays that have been investigated and characterized with respect to the microstructure represent two

  8. On the adsorption properties of magnetic fluids: Impact of bulk structure

    Kubovcikova, Martina [Institute of Experimental Physics, Slovak Academy of Sciences, Kosice (Slovakia); Gapon, Igor V. [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna (Russian Federation); Physics Department, Kyiv Taras Shevchenko National University, Kyiv (Ukraine); Zavisova, Vlasta [Institute of Experimental Physics, Slovak Academy of Sciences, Kosice (Slovakia); Koneracka, Martina, E-mail: konerack@saske.sk [Institute of Experimental Physics, Slovak Academy of Sciences, Kosice (Slovakia); Petrenko, Viktor I. [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna (Russian Federation); Physics Department, Kyiv Taras Shevchenko National University, Kyiv (Ukraine); Soltwedel, Olaf [Max-Planck-Institut for Solid State Research, Outstation at MLZ, Garching (Germany); Almasy, László [Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest (Hungary); Avdeev, Mikhail V. [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna (Russian Federation); Physical Faculty, St. Petersburg State University, Saint Petersburg (Russian Federation); Kopcansky, Peter [Institute of Experimental Physics, Slovak Academy of Sciences, Kosice (Slovakia)

    2017-04-01

    Adsorption of nanoparticles from magnetic fluids (MFs) on solid surface (crystalline silicon) was studied by neutron reflectometry (NR) and related to the bulk structural organization of MFs concluded from small-angle neutron scattering (SANS). The initial aqueous MF with nanomagnetite (co-precipitation reaction) stabilized by sodium oleate and MF modified by a biocompatible polymer, poly(ethylene glycol) (PEG), were considered. Regarding the bulk structure it was confirmed in the SANS experiment that comparatively small and compact (size~30 nm) aggregates of nanoparticle in the initial sample transfer to large and developed (size>130 nm, fractal dimension 2.7) associates in the PEG modified MF. This reorganization in the aggregates correlates with the changes in the neutron reflectivity that showed that a single adsorption layer of individual nanoparticles on the oxidized silicon surface for the initial MF disappears after the PEG modification. It is concluded that all particles in the modified fluid are in the aggregates that are not adsorbed by silicon. - Highlights: • Different bulk structure of initial MF and PEG modified MF was confirmed. • PEG modification of MF transforms small MNPs aggregates to large and developed. • Individual non-aggregated nanoparticles are preferably adsorbed on oxidized silicon. • Nanoparticles from MF form a single adsorption layer on the silicon surface. • PEG modified MF compose large developed aggregates that are not adsorbed by surface.

  9. Preparation, thermal stability, and magnetic properties of Fe-Zr-Mo-W-B bulk metallic glass

    Liu, D.Y.; Sun, W.S.; Wang, A.M.; Zhang, H.F.; Hu, Z.Q.

    2004-01-01

    A bulk metallic glass (BMG) cylinder of Fe 60 Co 8 Zr 10 Mo 5 W 2 B 15 with a diameter of 1.5 mm was prepared by copper mould casting of industrial raw materials. The amorphous state and the crystallization behavior were investigated by X-ray diffraction (XRD). The thermal stability parameters, such as glass transition temperature (T g ), crystallization temperature (T x ), supercooled liquid region (ΔT x ) between T g and T x , and reduced glass transition temperature T rg (T g /T m ) were measured by differential scanning calorimetry (DSC) to be 891, 950, 59 K, and 0.62, respectively. The crystallization process took place through a single stage, and involved crystallization of the phases α-Fe, ZrFe 2 , Fe 3 B, MoB 2 , Mo 2 FeB 2 , and an unknown phase, as determined by X-ray analysis of the sample annealed for 1.5 ks at 1023 K, 50 K above the DSC peak temperature of crystallization. Moessbauer spectroscopy was studied for this alloy. The spectra exhibit a broadened and asymmetric doublet-like structure that indicated paramagnetic behavior and a fully amorphous structure. α-Fe was found in the amorphous matrix for a cylinder with a diameter of 2.5 mm. The success of synthesis of the Fe-based bulk metallic glass from industrial materials is important for the future progress in research and practical application of new bulk metallic glasses

  10. Tritium permeation and recovery

    Bond, R.A.; Hamilton, A.M.

    1987-01-01

    The paper is an appendix to a study of the reactor relevance of the NET design concept. The latter study examines whether the technologies and design principles proposed for NET can be directly extrapolated to a demonstration (DEMO) reactor. In this appendix, tritium transport in the DEMO breeding blanket is considered with emphasis on the permeation rate from the lithium-lead breeder into the coolant. A computational model used to calculate the tritium transport in the breeder blanket is described. Results are reported for the tritium transport in the NET/INTOR type blanket as well as the DEMO blanket in order to provide a comparison. In addition, results are presented for the helium coolant tritium extraction analysis. (U.K.)

  11. Ion-Exchanged SAPO-34 Membranes for Krypton-Xenon Separation: Control of Permeation Properties and Fabrication of Hollow Fiber Membranes.

    Kwon, Yeon Hye; Min, Byunghyun; Yang, Shaowei; Koh, Dong-Yeun; Bhave, Ramesh R; Nair, Sankar

    2018-02-21

    Separation of radioisotope 85 Kr from 136 Xe is of importance in used nuclear fuel reprocessing. Membrane separation based on zeolite molecular sieves such as chabazite SAPO-34 is an attractive alternative to energy-intensive cryogenic distillation. We report the synthesis of SAPO-34 membranes with considerably enhanced performance via thickness reduction based upon control of a steam-assisted vapor-solid conversion technique followed by ion exchange with alkali metal cations. The reduction of membrane thickness leads to a large increase in Kr permeance from 7.5 to 26.3 gas permeation units (GPU) with ideal Kr/Xe selectivities >20 at 298 K. Cation-exchanged membranes show large (>50%) increases in selectivity at ambient or slight subambient conditions. The adsorption, diffusion, and permeation characteristics of ion-exchanged SAPO-34 materials and membranes are investigated in detail, with potassium-exchanged SAPO-34 membranes showing particularly attractive performance. We then demonstrate the fabrication of selective SAPO-34 membranes on α-alumina hollow fibers.

  12. The microstructure network and thermoelectric properties of bulk (Bi,Sb)2Te3

    Xie, Wenjie; Hitchcock, Dale A.; Kang, Hye J.

    2012-01-01

    We report small-angle neutron scattering studies on the microstructure network in bulk (Bi,Sb)(2)Te-3 synthesized by the melt-spinning (MS) and the spark-plasma-sintering (SPS) process. We find that rough interfaces of multiscale microstructures generated by the MS are responsible for the large...... reduction of both lattice thermal conductivity and electrical conductivity. Our study also finds that subsequent SPS forms a microstructure network of similar to 10 nm thick lamellae and smooth interfaces between them. This nanoscale microstructure network with smooth interfaces increases electrical...... conductivity while keeping a low thermal conductivity, making it an ideal microstructure for high thermoelectric efficiency....

  13. Structural, electronic, and optical properties of the C-C complex in bulk silicon from first principles

    Timerkaeva, Dilyara; Attaccalite, Claudio; Brenet, Gilles; Caliste, Damien; Pochet, Pascal

    2018-04-01

    The structure of the CiCs complex in silicon has long been the subject of debate. Numerous theoretical and experimental studies have attempted to shed light on the properties of these defects that are at the origin of the light emitting G-center. These defects are relevant for applications in lasing, and it would be advantageous to control their formation and concentration in bulk silicon. It is therefore essential to understand their structural and electronic properties. In this paper, we present the structural, electronic, and optical properties of four possible configurations of the CiCs complex in bulk silicon, namely, the A-, B-, C-, and D-forms. The configurations were studied by density functional theory and many-body perturbation theory. Our results suggest that the C-form was misinterpreted as a B-form in some experiments. Our optical investigation also tends to exclude any contribution of A- and B-forms to light emission. Taken together, our results suggest that the C-form could play an important role in heavily carbon-doped silicon.

  14. Single-cell vs. bulk activity properties of coastal bacterioplankton over an annual cycle in a temperate ecosystem.

    Morán, Xosé Anxelu G; Calvo-Díaz, Alejandra

    2009-01-01

    The connections between single-cell activity properties of heterotrophic planktonic bacteria and whole community metabolism are still poorly understood. Here, we show flow cytometry single-cell analysis of membrane-intact (live), high nucleic acid (HNA) content and actively respiring (CTC+) bacteria with samples collected monthly during 2006 in northern Spain coastal waters. Bulk activity was assessed by measuring 3H-Leucine incorporation and specific growth rates. Consistently, different single-cell relative abundances were found, with 60-100% for live, 30-84% for HNA and 0.2-12% for CTC+ cells. Leucine incorporation rates (2-153 pmol L(-1) h(-1)), specific growth rates (0.01-0.29 day(-1)) and the total and relative abundances of the three single-cell groups showed marked seasonal patterns. Distinct depth distributions during summer stratification and different relations with temperature, chlorophyll and bacterial biovolume suggest the existence of different controlling factors on each single-cell property. Pooled leucine incorporation rates were similarly correlated with the abundance of all physiological groups, while specific growth rates were only substantially explained by the percentage of CTC+ cells. However, the ability to reduce CTC proved notably better than the other two single-cell properties at predicting bacterial bulk rates within seasons, suggesting a tight linkage between bacterial individual respiration and biomass production at the community level.

  15. Effect of Ca substitution on some physical properties of nano-structured and bulk Ni-ferrite samples

    Assar, S. T.; Abosheiasha, H. F.

    2015-01-01

    Nanoparticles of Ni1-xCaxFe2O4 (x=0.0, 0.02, 0.04, 0.06 and 0.10) were prepared by citrate precursor method. A part of these samples was sintered at 600 °C for 2 h in order to keep the particles within the nano-size while the other part was sintered at 1000 °C to let the particles to grow to the bulk size. The effect of Ca2+ ion substitution in nickel ferrite on some structural, magnetic, electrical and thermal properties was investigated. All samples were characterized by using X-ray diffraction (XRD), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR) and vibrating sample magnetometer (VSM). A two probe method was used to measure the dc electrical conductivity whereas the photoacoustic (PA) technique was used to determine the thermal diffusivity of the samples. To interpret different experimental results for nano and bulk samples some cation distributions were assumed based on the VSM and XRD data. These suggested cation distributions give logical explanations for other experimental results such as the observed values of the absorption bands in FTIR spectra and the dc conductivity results. Finally, in the thermal measurements it was found that increasing the Ca2+ ion content causes a decrease in the thermal diffusivity of both nano and bulk samples. The explanation of this behavior is ascribed to the phonon-phonon scattering.

  16. The structural properties of Zr-based bulk metallic glasses subjected to high pressure torsion at different temperatures

    Boltynjuk, E. V., E-mail: boltynjuk@gmail.com; Ubyivovk, E. V.; Kshumanev, A. M. [Saint Petersburg State University, 28 Universitetskiy pr., Saint Petersburg, 198504 (Russian Federation); Gunderov, D. V.; Lukianov, A. V. [Ufa State Aviation Technical University, K. Marks 12, Ufa, 450000 (Russian Federation); Bednarz, A. [Faculty of Mechanical Engineering and Aeronautics, Department of Aircraft and Aircraft Engines, Rzeszow University of Technology, Al. Powstancow Warszawy 8, 35-959 Rzeszow (Poland); Valiev, R. Z. [Saint Petersburg State University, 28 Universitetskiy pr., Saint Petersburg, 198504 (Russian Federation); Ufa State Aviation Technical University, K. Marks 12, Ufa, 450000 (Russian Federation)

    2016-06-17

    The structural properties of a Zr{sub 62}Cu{sub 22}Al{sub 10}Fe{sub 5}Dy{sub 1} bulk metallic glasses were investigated. Cylindrical rods of the Zr{sub 62}Cu{sub 22}Al{sub 10}Fe{sub 5}Dy{sub 1} BMG were subjected to high pressure torsion at temperatures of 20°C and 150°C. X-ray diffraction, transmission electron microscopy were used to determine peculiarities of the modified structure. Analysis of fracture surfaces, nanohardness measurements were conducted to investigate the influence of structural changes on mechanical behavior of processed samples.

  17. The structural properties of Zr-based bulk metallic glasses subjected to high pressure torsion at different temperatures

    Boltynjuk, E. V.; Ubyivovk, E. V.; Kshumanev, A. M.; Gunderov, D. V.; Lukianov, A. V.; Bednarz, A.; Valiev, R. Z.

    2016-01-01

    The structural properties of a Zr_6_2Cu_2_2Al_1_0Fe_5Dy_1 bulk metallic glasses were investigated. Cylindrical rods of the Zr_6_2Cu_2_2Al_1_0Fe_5Dy_1 BMG were subjected to high pressure torsion at temperatures of 20°C and 150°C. X-ray diffraction, transmission electron microscopy were used to determine peculiarities of the modified structure. Analysis of fracture surfaces, nanohardness measurements were conducted to investigate the influence of structural changes on mechanical behavior of processed samples.

  18. Texturing for bulk α-Fe/Nd2Fe14B nanocomposites with enhanced magnetic properties

    Lou, L.; Hou, F.C.; Wang, Y.N.; Cheng, Y.; Li, H.L.; Li, W.; Guo, D.F.; Li, X.H.; Zhang, X.Y.

    2014-01-01

    In the present study, the texturing of bulk α-Fe/Nd 2 Fe 14 B nanocomposites produced from Nd-lean amorphous Nd x Fe 92.5−x Cu 1.5 B 6 (x=9 to 11.5 at%) via a hot deformation under a uniaxial stress of ∼350 MPa at 973 K has been studied. An enhanced (00l) texture of the hard phase is observed with increasing Nd content, which results in an increase in the magnetic anisotropy of the nanocomposite magnets. As a result, both the coercivity and the remanence of the magnets increase simultaneously with increasing Nd content from x=9–11.5 at%, yielding a significant enhancement of the maximum energy product from (BH) max =13.2 to 17.5 MGOe in the direction parallel to stress axis. - Highlights: • Textured bulk α-Fe/Nd 2 Fe 14 B nanocomposites have been produced from Nd-lean alloys. • Nd content has an effect on the texturing of α-Fe/Nd 2 Fe 14 B nanocomposite magnets. • An enhanced (00l) texture of hard phase is observed with increasing Nd content. • Both the coercivity and remanence increase simultaneously with Nd content

  19. Ac conductivity and dielectric properties of bulk tin phthalocyanine dichloride (SnPcCl 2)

    El-Nahass, M. M.; Farid, A. M.; Abd El-Rahman, K. F.; Ali, H. A. M.

    2008-07-01

    The ac conductivity, σac( ω), has been measured for bulk tin phthalocyanine dichloride (SnPcCl 2) in the form of compressed pellet with evaporated ohmic Au electrodes in a temperature range 303-403 K. Ac conductivity, σac( ω), is found to vary as ωs in the frequency range 42 Hz-5×10 6 Hz. At low range of frequency, s<1 and it decreases with the increase in temperature indicating a dominant hopping process. At high range of frequency, s is found to be equal to ≈1.09 and is temperature independent. The dielectric constant, ε1, and dialectic loss, ε2, have been determined for bulk SnPcCl 2. Both ε1 and ε2 decrease with the increase in frequency and increase with the increase in temperature. The Cole-Cole types have been used to determine some parameters such as; the macroscopic relaxation time ( τo), the molecular relaxation time ( τ), the activation energy for relaxation ( Eo) and the distribution parameter ( α). The temperature dependence of τ is expressed by a thermally activated process with the activation energy of 0.299 eV.

  20. Controlled Bulk Properties of Composite Polymeric Solutions for Extensive Structural Order of Honeycomb Polysulfone Membranes.

    Gugliuzza, Annarosa; Perrotta, Maria Luisa; Drioli, Enrico

    2016-05-16

    This work provides additional insights into the identification of operating conditions necessary to overcome a current limitation to the scale-up of the breath figure method, which is regarded as an outstanding manufacturing approach for structurally ordered porous films. The major restriction concerns, indeed, uncontrolled touching droplets at the boundary. Herein, the bulk of polymeric solutions are properly managed to generate honeycomb membranes with a long-range structurally ordered texture. Water uptake and dynamics are explored as chemical environments are changed with the intent to modify the hydrophilic/hydrophobic balance and local water floatation. In this context, a model surfactant such as the polyoxyethylene sorbitan monolaurate is used in combination with alcohols at different chain length extents and a traditional polymer such as the polyethersufone. Changes in the interfacial tension and kinematic viscosity taking place in the bulk of composite solutions are explored and examined in relation to competitive droplet nucleation and growth rate. As a result, extensive structurally ordered honeycomb textures are obtained with the rising content of the surfactant while a broad range of well-sized pores is targeted as a function of the hydrophilic-hydrophobic balance and viscosity of the composite polymeric mixture. The experimental findings confirm the consistency of the approach and are expected to give propulsion to the commercially production of breath figures films shortly.

  1. Controlled Bulk Properties of Composite Polymeric Solutions for Extensive Structural Order of Honeycomb Polysulfone Membranes

    Annarosa Gugliuzza

    2016-05-01

    Full Text Available This work provides additional insights into the identification of operating conditions necessary to overcome a current limitation to the scale-up of the breath figure method, which is regarded as an outstanding manufacturing approach for structurally ordered porous films. The major restriction concerns, indeed, uncontrolled touching droplets at the boundary. Herein, the bulk of polymeric solutions are properly managed to generate honeycomb membranes with a long-range structurally ordered texture. Water uptake and dynamics are explored as chemical environments are changed with the intent to modify the hydrophilic/hydrophobic balance and local water floatation. In this context, a model surfactant such as the polyoxyethylene sorbitan monolaurate is used in combination with alcohols at different chain length extents and a traditional polymer such as the polyethersufone. Changes in the interfacial tension and kinematic viscosity taking place in the bulk of composite solutions are explored and examined in relation to competitive droplet nucleation and growth rate. As a result, extensive structurally ordered honeycomb textures are obtained with the rising content of the surfactant while a broad range of well-sized pores is targeted as a function of the hydrophilic-hydrophobic balance and viscosity of the composite polymeric mixture. The experimental findings confirm the consistency of the approach and are expected to give propulsion to the commercially production of breath figures films shortly.

  2. Development of DPD coarse-grained models: From bulk to interfacial properties

    Solano Canchaya, José G.; Dequidt, Alain, E-mail: alain.dequidt@univ-bpclermont.fr; Goujon, Florent; Malfreyt, Patrice [Institut de Chimie de Clermont-Ferrand, Université Blaise Pascal, Université Clermont Auvergne, BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR 6296, ICCF, F-63178 Aubiere (France)

    2016-08-07

    A new Bayesian method was recently introduced for developing coarse-grain (CG) force fields for molecular dynamics. The CG models designed for dissipative particle dynamics (DPD) are optimized based on trajectory matching. Here we extend this method to improve transferability across thermodynamic conditions. We demonstrate the capability of the method by developing a CG model of n-pentane from constant-NPT atomistic simulations of bulk liquid phases and we apply the CG-DPD model to the calculation of the surface tension of the liquid-vapor interface over a large range of temperatures. The coexisting densities, vapor pressures, and surface tensions calculated with different CG and atomistic models are compared to experiments. Depending on the database used for the development of the potentials, it is possible to build a CG model which performs very well in the reproduction of the surface tension on the orthobaric curve.

  3. Microstructure and mechanical properties of bulk highly faulted fcc/hcp nanostructured cobalt microstructures

    Barry, Aliou Hamady [Université Paris 13, Sorbonne Paris Cité, LSPM CNRS UPR 3407, 93430 Villetaneuse (France); Laboratoire Chimie des Matériaux, Département de Chimie, Faculté des Sciences et Technique, Université de Nouakchott (Mauritania, Islamic Republic of); Dirras, Guy, E-mail: dirras@unv-paris13.fr [Université Paris 13, Sorbonne Paris Cité, LSPM CNRS UPR 3407, 93430 Villetaneuse (France); Schoenstein, Frederic; Tétard, Florent; Jouini, Noureddine [Université Paris 13, Sorbonne Paris Cité, LSPM CNRS UPR 3407, 93430 Villetaneuse (France)

    2014-05-01

    Nanostructured cobalt powders with an average particle size of 50 nm were synthesized using a polyol method and subsequently consolidated by spark plasma sintering (SPS). SPS experiments performed at 650 °C with sintering times ranging from 5 to 45 min under a pressure of 100 MPa, yielded to dense bulk nanostructured cobalt (relative density greater than 97%). X-ray diffraction patterns of the as-prepared powders showed only a face centered cubic (fcc) crystalline phase, whereas the consolidated samples exhibited a mixture of both fcc and hexagonal close packed (hcp) phases. Transmission electron microscopy observations revealed a lamellar substructure with a high density of nanotwins and stacking faults in every grain of the sintered samples. Room temperature compression tests, carried out at a strain rate of 10{sup −3} s{sup −1}, yielded to highest strain to fracture values of up to 5% for sample of holding time of 15 min, which exhibited a yield strength of 1440 MPa, an ultimate strength as high as 1740 MPa and a Young's modulus of 205 GPa. The modulus of elasticity obtained from the nanoindentation tests, ranges from 181 to 218 GPa. The lowest modulus value of 181 GPa was obtained for the sample with the highest sintering time (45 min), which could be related to mass density loss as a consequence of trapped gases releasing. - Highlights: • Co nanopowder (50 nm) was prepared by reduction in polyol medium. • SPS was used to process bulk nanostructured Co specimens. • Microstructures were made of intricate fcc/hcp, along with nanotwins and SFs. • High strengths and moderate compressive ductility were obtained. • Deformation mechanisms related to complex interplay of different length scales.

  4. Cospectral budget of turbulence explains the bulk properties of smooth pipe flow

    Katul, Gabriel G.; Manes, Costantino

    2014-12-01

    Connections between the wall-normal turbulent velocity spectrum Ew w(k ) at wave number k and the mean velocity profile (MVP) are explored in pressure-driven flows confined within smooth walls at moderate to high bulk Reynolds numbers (Re). These connections are derived via a cospectral budget for the longitudinal (u') and wall-normal (w') velocity fluctuations, which include a production term due to mean shear interacting with Ew w(k ) , viscous effects, and a decorrelation between u' and w' by pressure-strain effects [=π (k ) ]. The π (k ) is modeled using a conventional Rotta-like return-to-isotropy closure but adjusted to include the effects of isotropization of the production term. The resulting cospectral budget yields a generalization of a previously proposed "spectral link" between the MVP and the spectrum of turbulence. The proposed cospectral budget is also shown to reproduce the measured MVP across the pipe with changing Re including the MVP shapes in the buffer and wake regions. Because of the links between Ew w(k ) and the MVP, the effects of intermittency corrections to inertial subrange scales and the so-called spectral bottleneck reported as k approaches viscous dissipation eddy sizes (η ) on the MVP shapes are investigated and shown to be of minor importance. Inclusion of a local Reynolds number correction to a parameter associated with the spectral exponential cutoff as k η →1 appears to be more significant to the MVP shape in the buffer region. While the bulk shape of the MVP is reasonably reproduced in all regions of the pipe, the solution to the cospectral budget systematically underestimates the negative curvature of the MVP within the buffer layer.

  5. Cospectral budget of turbulence explains the bulk properties of smooth pipe flow.

    Katul, Gabriel G; Manes, Costantino

    2014-12-01

    Connections between the wall-normal turbulent velocity spectrum E(ww)(k) at wave number k and the mean velocity profile (MVP) are explored in pressure-driven flows confined within smooth walls at moderate to high bulk Reynolds numbers (Re). These connections are derived via a cospectral budget for the longitudinal (u') and wall-normal (w') velocity fluctuations, which include a production term due to mean shear interacting with E(ww)(k), viscous effects, and a decorrelation between u' and w' by pressure-strain effects [=π(k)]. The π(k) is modeled using a conventional Rotta-like return-to-isotropy closure but adjusted to include the effects of isotropization of the production term. The resulting cospectral budget yields a generalization of a previously proposed "spectral link" between the MVP and the spectrum of turbulence. The proposed cospectral budget is also shown to reproduce the measured MVP across the pipe with changing Re including the MVP shapes in the buffer and wake regions. Because of the links between E(ww)(k) and the MVP, the effects of intermittency corrections to inertial subrange scales and the so-called spectral bottleneck reported as k approaches viscous dissipation eddy sizes (η) on the MVP shapes are investigated and shown to be of minor importance. Inclusion of a local Reynolds number correction to a parameter associated with the spectral exponential cutoff as kη→1 appears to be more significant to the MVP shape in the buffer region. While the bulk shape of the MVP is reasonably reproduced in all regions of the pipe, the solution to the cospectral budget systematically underestimates the negative curvature of the MVP within the buffer layer.

  6. First-principles calculations of bulk and interfacial thermodynamic properties for fcc-based Al-Sc alloys

    Asta, M.; Foiles, S.M.; Quong, A.A.

    1998-01-01

    The configurational thermodynamic properties of fcc-based Al-Sc alloys and coherent Al/Al 3 Sc interphase-boundary interfaces have been calculated from first principles. The computational approach used in this study combines the results of pseudopotential total-energy calculations with a cluster-expansion description of the alloy energetics. Bulk and interface configurational-thermodynamic properties are computed using a low-temperature-expansion technique. Calculated values of the {100} and {111} Al/Al 3 Sc interfacial energies at zero temperature are, respectively, 192 and 226mJ/m 2 . The temperature dependence of the calculated interfacial free energies is found to be very weak for {100} and more appreciable for {111} orientations; the primary effect of configurational disordering at finite temperature is to reduce the degree of crystallographic anisotropy associated with calculated interfacial free energies. The first-principles-computed solid-solubility limits for Sc in bulk fcc Al are found to be underestimated significantly in comparison with experimental measurements. It is argued that this discrepancy can be largely attributed to nonconfigurational contributions to the entropy which have been neglected in the present thermodynamic calculations. copyright 1998 The American Physical Society

  7. Deuterium permeation and diffusion in high-purity beryllium

    Abramov, E.; Riehm, M.P.; Thompson, D.A.; Smeltzer, W.W.

    1990-01-01

    The permeation rate of deuterium through high-purity beryllium membranes was measured using the gas-driven permeation technique. The time-dependent and the steady-state deuterium flux data were analyzed and the effective diffusivities of the samples were determined. Using multilayer permeation theory the effects of surface oxide were eliminated and the diffusion coefficients of the bulk beryllium determined. The diffusion parameters obtained for the extra-grade beryllium samples (99.8%) are D 0 =6.7x10 -9 m 2 /s and E D =28.4 kJ/mol. For the high-grade beryllium samples (99%) the parameters are D 0 =8.0x10 -9 m 2 /s and E D =35.1 kJ/mol. (orig.)

  8. Deuterium permeation and diffusion in high purity beryllium

    Abramov, E.

    1990-05-01

    The permeation rate of deuterium through high-purity beryllium membranes was measured using the gas-driven permeation technique. The time-dependent and the steady-state deuterium flux data were analyzed and the effective diffusivities of the samples were determined. A multilayer permeation theory was used in order to eliminate the surface oxide effects and the diffusion coefficients of the bulk beryllium were determined. The diffusion parameters obtained for the extra-grade beryllium samples (99.8%) are D 0 = 6.7 x 10 -9 [m 2 /s] and E D = 28.4 [KJ/mol]; and for the high-grade beryllium samples (99%) the parameters are D 0 = 8.0 x 10 -9 [m 2 /s] and E D = 35.1 [KJ/mol

  9. Formation of SiNx:H by PECVD: optimization of the optical, bulk passivation and structural properties for photovoltaic applications

    Lelievre, J.F.

    2007-04-01

    The hydrogenated silicon nitride SiNx:H is widely used as antireflection coating and passivation layer in the manufacture of silicon photovoltaic cells. The aim of this work was to implement a low frequency (440 kHz) PECVD reactor and to characterize the obtained SiN layers. After having determined the parameters of the optimal deposition, the physico-chemical structure of the layers has been studied. The optical properties have been studied with the aim to improve the antireflection coating of the photovoltaic cells. The surface and bulk passivation properties, induced by the SiN layer in terms of its stoichiometry, have been analyzed and have revealed the excellent passivating efficiency of this material. At last, have been studied the formation conditions of the silicon nano-crystals in the SiN matrix. (O.M.)

  10. Penetration of radionuclides across the skin. Rat age dependent promethium permeation through skin in vitro

    Kassai, Z.; Kassai, A.; Bauerova, K.; Koprda, V.; Harangozo, M.; Bendova, P.; Bujnova, A.

    2003-01-01

    The composition and the permeation properties of the skin are dependent on age. In the animal models for permation studies, age affects the mechanical as well as the permeation properties significantly. The time dependence of permeation of 147 Pm 3+ from aqueous solution was established by the animal skin model and the age dependence of promethium permeation through the skin was examined. The aim was to find the optimum rat skin age model for radionuclide permeation studies and to assess the relative importance of the main permeation pathways: transepidermal and transfollicular permeation. The skin from 5-day-old rats (5DR) was found to represent the optimum animal model to study transepidermal permeation of ions. The skin from 9-day-old rats (9DR) was selected to study transfollicular permeation of ions. Comparison of the permeated amounts of promethium through the skin without hairs (3 DR to 6 DR) and with hairs (7DR to 12DR) showed that the additional permation mode via follicles significantly contributed to the permeation rate and extent. (author)

  11. Determination of the plastic deformation and residual stress tensor distribution using surface and bulk intrinsic magnetic properties

    Hristoforou, E.; Svec, P. Sr.

    2015-01-01

    We have developed an unique method to provide the stress calibration curve in steels: performing flaw-less welding in the under examination steel, we obtained to determine the level of the local plastic deformation and the residual stress tensors. These properties where measured using both the X-ray and the neutron diffraction techniques, concerning their surface and bulk stresses type II (intra-grain stresses) respectively, as well as the stress tensor type III by using the electron diffraction technique. Measuring the distribution of these residual stresses along the length of a welded sample or structure, resulted in determining the local stresses from the compressive to tensile yield point. Local measurement of the intrinsic surface and bulk magnetic property tensors allowed for the un-hysteretic correlation. The dependence of these local magnetic tensors with the above mentioned local stress tensors, resulting in a unique and almost un-hysteretic stress calibration curve of each grade of steel. This calibration integrated the steel's mechanical and thermal history, as well as the phase transformations and the presence of precipitations occurring during the welding process.Additionally to that, preliminary results in different grade of steels reveal the existence of a universal law concerning the dependence of magnetic and magnetostrictive properties of steels on their plastic deformation and residual stress state, as they have been accumulated due to their mechanical and thermal fatigue and history. This universality is based on the unique dependence of the intrinsic magnetic properties of steels normalized with a certain magnetoelastic factor, upon the plastic deformation or residual stress state, which, in terms, is normalized with their yield point of stress. (authors)

  12. Thermo-mechanical properties of W/Mo markers coatings deposited on bulk W

    Grigore, E; Ruset, C; Gherendi, M; Chioibasu, D; Hakola, A

    2016-01-01

    In the present paper marker structures consisting of W/Mo layers were deposited on bulk W samples by using a modified CMSII method. This technology, compared to standard CMSII, prevents the formation of nano-pore structures at interfaces. The thicknesses of the markers were in the range 20–35 μm to balance the requirements associated with the wall erosion in ITER and thermo-mechanical performances. The coatings structure and composition were evaluated by glow discharge optical emission spectrometry (GDOES), and energy dispersive x-ray spectroscopy measurements (EDX). The adhesion of the coatings to the substrate has been assessed by scratch test method. In order to evaluate their effectiveness as potential markers for fusion applications, the marker coatings have been tested in an electron beam facility at a temperature of 1000 °C and a power density of about 3 MW m −2 . A number of 300 pulses with duration of 420 s (35 testing hours) were applied on the marker coated samples. (paper)

  13. Thermo-mechanical properties of W/Mo markers coatings deposited on bulk W

    Grigore, E.; Ruset, C.; Gherendi, M.; Chioibasu, D.; Hakola, A.; contributors, JET

    2016-02-01

    In the present paper marker structures consisting of W/Mo layers were deposited on bulk W samples by using a modified CMSII method. This technology, compared to standard CMSII, prevents the formation of nano-pore structures at interfaces. The thicknesses of the markers were in the range 20-35 μm to balance the requirements associated with the wall erosion in ITER and thermo-mechanical performances. The coatings structure and composition were evaluated by glow discharge optical emission spectrometry (GDOES), and energy dispersive x-ray spectroscopy measurements (EDX). The adhesion of the coatings to the substrate has been assessed by scratch test method. In order to evaluate their effectiveness as potential markers for fusion applications, the marker coatings have been tested in an electron beam facility at a temperature of 1000 °C and a power density of about 3 MW m-2. A number of 300 pulses with duration of 420 s (35 testing hours) were applied on the marker coated samples.

  14. Structure and properties of cerium oxides in bulk and nanoparticulate forms

    Gangopadhyay, Shruba; Frolov, Dmitry D.; Masunov, Artëm E.; Seal, Sudipta

    2014-01-01

    The experimental and computational studies on the cerium oxide nanoparticles, as well as stoichiometric phases of bulk ceria are reviewed. Based on structural similarities of these phases in hexagonal aspect, electroneutral and non-polar pentalayers are identified as building blocks of type A sesquioxide structure. The idealized core/shell structure of the ceria nanoparticles is described as dioxide core covered by a single pentalayer of sesquioxide, which explains the exceptional stability of subsurface vacancies in nanoceria. The density functional theory (DFT) predictions of the lattice parameters and elastic moduli for the Ce(IV) and Ce(III) oxides at the hybrid DFT level are also presented. The calculated values for both compounds agree with available experimental data and allow predicting changes in the lattice parameter with decreasing size of the nanoparticles. The lattice parameter is calculated as equilibrium between contraction of sesquioxide structure in the core, and expansion of dioxide structure in the shell of the nanoparticle. This is consistent with available XRD data on ceria NPs obtained in mild aqueous conditions. The core/shell model, however, breaks down when applied to the size dependence of lattice parameter in NPs obtained by the laser ablation techniques

  15. Synthesis and gas permeation properties of a novel thermally-rearranged polybenzoxazole made from an intrinsically microporous hydroxyl-functionalized triptycene-based polyimide precursor

    Alghunaimi, Fahd; Ghanem, Bader; Wang, Yingge; Salinas, Octavio; Alaslai, Nasser Y.; Pinnau, Ingo

    2017-01-01

    A hydroxyl-functionalized triptycene-based polyimide of intrinsic microporosity (TDA1-APAF) was converted to a polybenzoxazole (PBO) by heat treatment at 460 °C under nitrogen atmosphere. TDA1-APAF treated for 15 min (TR 460) resulted in a PBO conversion of 95% based on a theoretical weight loss of 11.7 wt% of the polyimide precursor. The BET surface area of the TR 460 (680 m2 g−1) was significantly higher than that of the TDA1-APAF polyimide (260 m2 g−1) as determined by nitrogen adsorption at −196 °C. Heating TDA1-APAF for 30 min (TRC 460) resulted in a weight loss of 13.5 wt%, indicating full conversion to PBO and partial main-chain degradation. The TR 460 membrane displayed excellent O2 permeability of 311 Barrer coupled with an O2/N2 selectivity of 5.4 and CO2 permeability of 1328 Barrer with a CO2/CH4 selectivity of 27. Interestingly, physical aging over 150 days resulted in enhanced O2/N2 selectivity of 6.3 with an O2 permeability of 185 Barrer. The novel triptycene-based TR 460 PBO outperformed all previously reported APAF-polyimide-based PBOs with gas permeation performance close to recently reported polymers located on the 2015 O2/N2 upper bound. Based on this study, thermally-rearranged membranes from hydroxyl-functionalized triptycene-based polyimides are promising candidate membrane materials for air separation, specifically in applications where space and weight of membrane systems are of utmost importance such as nitrogen production for inert atmospheres in fuel lines and tanks on aircrafts and off-shore oil- or natural gas platforms. Mixed-gas permeation experiments also demonstrated good performance of the TR 460 membrane for natural gas sweetening with a CO2 permeability of ∼1000 Barrer and CO2/CH4 selectivity of 22 at a typical CO2 wellhead partial pressure of 10 bar.

  16. Synthesis and gas permeation properties of a novel thermally-rearranged polybenzoxazole made from an intrinsically microporous hydroxyl-functionalized triptycene-based polyimide precursor

    Alghunaimi, Fahd

    2017-06-06

    A hydroxyl-functionalized triptycene-based polyimide of intrinsic microporosity (TDA1-APAF) was converted to a polybenzoxazole (PBO) by heat treatment at 460 °C under nitrogen atmosphere. TDA1-APAF treated for 15 min (TR 460) resulted in a PBO conversion of 95% based on a theoretical weight loss of 11.7 wt% of the polyimide precursor. The BET surface area of the TR 460 (680 m2 g−1) was significantly higher than that of the TDA1-APAF polyimide (260 m2 g−1) as determined by nitrogen adsorption at −196 °C. Heating TDA1-APAF for 30 min (TRC 460) resulted in a weight loss of 13.5 wt%, indicating full conversion to PBO and partial main-chain degradation. The TR 460 membrane displayed excellent O2 permeability of 311 Barrer coupled with an O2/N2 selectivity of 5.4 and CO2 permeability of 1328 Barrer with a CO2/CH4 selectivity of 27. Interestingly, physical aging over 150 days resulted in enhanced O2/N2 selectivity of 6.3 with an O2 permeability of 185 Barrer. The novel triptycene-based TR 460 PBO outperformed all previously reported APAF-polyimide-based PBOs with gas permeation performance close to recently reported polymers located on the 2015 O2/N2 upper bound. Based on this study, thermally-rearranged membranes from hydroxyl-functionalized triptycene-based polyimides are promising candidate membrane materials for air separation, specifically in applications where space and weight of membrane systems are of utmost importance such as nitrogen production for inert atmospheres in fuel lines and tanks on aircrafts and off-shore oil- or natural gas platforms. Mixed-gas permeation experiments also demonstrated good performance of the TR 460 membrane for natural gas sweetening with a CO2 permeability of ∼1000 Barrer and CO2/CH4 selectivity of 22 at a typical CO2 wellhead partial pressure of 10 bar.

  17. Effect of metallurgical factors on the bulk magnetic properties of non-oriented electrical steels

    Ghosh, Pampa, E-mail: pampaghosh@gmail.com [Department of Mining and Materials Engineering, McGill University, 3610 University Street, Montreal, Que., Canada H3A 0C5 (Canada); Chromik, Richard R., E-mail: richard.chromik@mcgill.ca [Department of Mining and Materials Engineering, McGill University, 3610 University Street, Montreal, Que., Canada H3A 0C5 (Canada); Knight, Andrew M. [Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alta., Canada T6G 2V4 (Canada); Wakade, Shekhar G. [GM Powertrain, General Motors Company, 823 Joslyn Avenue, Building B, 4AJ35, Pontiac, MI 48340-2920 (United States)

    2014-04-01

    Non-oriented electrical steel (NOES) is one of the most common material used in electrical motors. Core loss and permeability are the most important properties that the motor manufacturers look for. Both these properties are structure sensitive and depend on several metallurgical factors; such as chemistry, grain size, crystallographic texture, cleanliness and stress states in non-oriented electrical steels. It has been observed in this course of the study that the grain size and Si content of NOES are the primary controlling factors to core loss, especially at higher frequencies. On the contrary, crystallographic texture plays an important role at lower frequencies. At higher frequency, core loss increases with increasing grain size and decreasing Si content of the steels. Small difference in grain size (∼50 μm) at lower frequency range has little influence on the magnetic properties but has significant adverse effect as frequency reaches high enough. - Highlights: • Magnetic properties of a set of electrical steels were measured. • Crystallographic texture, chemistry and grain size were studied for their effects on core loss and permeability. • Structure–magnetic property relationships were identified for the electrical steels.

  18. INFLUENCE OF RARE-EARTH ELEMENTS ON THE ELECTRICAL AND OPTICAL PROPERTIES OF INP BULK CRYSTALS

    Yatskiv, Roman; Zavadil, Jiří; Pekárek, Ladislav

    -, - (2011), s. 58-65 ISSN 1335-9053. [Development of Materials Science in Research and Education . Závažná Poruba, 31.08.2009-04.09.2009] Institutional research plan: CEZ:AV0Z20670512 Keywords : Crystal growth * REEs elements * Electrical properties Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  19. Effect of crystallographic texture on the bulk magnetic properties of non-oriented electrical steels

    Ghosh, Pampa, E-mail: pampaghosh@gmail.com [Department of Mining and Materials Engineering, McGill University, 3610 University Street, Montreal, Quebec, Canada H3A 0C5 (Canada); Chromik, Richard R., E-mail: richard.chromik@mcgill.ca [Department of Mining and Materials Engineering, McGill University, 3610 University Street, Montreal, Quebec, Canada H3A 0C5 (Canada); Vashegi, Babak; Knight, Andrew M. [Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada T6G 2V4 (Canada)

    2014-09-01

    Quantitative physical models for non-oriented electrical steels require precise knowledge of chemical and microstructural parameters for the material, with crystallographic texture being one of the most important. Describing the structure–property relationships in these materials is made difficult in that all of the parameters have an effect on magnetic properties. In the present study, a set of non-oriented electrical steel specimens are examined, where chemistry and grain size are kept similar from sample to sample, but texture is varied. A new texture parameter called Magnetic Texture Factor is introduced which is defined as the ratio of the volume fractions of 〈100〉 direction to 〈111〉 direction along magnetization vector. It was found that this Magnetic Texture Factor was a better parameter for identifying trends of magnetic properties with crystallographic texture than the often used Texture Factor, which is described as the ratio of the volume fractions of {100} planes to {111} planes. - Highlights: • Magnetic properties of a set of electrical steels were measured. • The effect of crystallographic texture was isolated from other material parameters. • A new texture factor is introduced called the Magnetic Texture Factor.

  20. Bulk and surface properties of liquid Al-Cr and Cr-Ni alloys

    Novakovic, R

    2011-01-01

    The energetics of mixing and structural arrangement in liquid Al-Cr and Cr-Ni alloys has been analysed through the study of surface properties (surface tension and surface segregation), dynamic properties (chemical diffusion) and microscopic functions (concentration fluctuations in the long-wavelength limit and chemical short-range order parameter) in the framework of statistical mechanical theory in conjunction with quasi-lattice theory. The Al-Cr phase diagram exhibits the existence of different intermetallic compounds in the solid state, while that of Cr-Ni is a simple eutectic-type phase diagram at high temperatures and includes the low-temperature peritectoid reaction in the range near a CrNi 2 composition. Accordingly, the mixing behaviour in Al-Cr and Cr-Ni alloy melts was studied using the complex formation model in the weak interaction approximation and by postulating Al 8 Cr 5 and CrNi 2 chemical complexes, respectively, as energetically favoured.

  1. Bulk and surface properties of liquid Al-Cr and Cr-Ni alloys.

    Novakovic, R

    2011-06-15

    The energetics of mixing and structural arrangement in liquid Al-Cr and Cr-Ni alloys has been analysed through the study of surface properties (surface tension and surface segregation), dynamic properties (chemical diffusion) and microscopic functions (concentration fluctuations in the long-wavelength limit and chemical short-range order parameter) in the framework of statistical mechanical theory in conjunction with quasi-lattice theory. The Al-Cr phase diagram exhibits the existence of different intermetallic compounds in the solid state, while that of Cr-Ni is a simple eutectic-type phase diagram at high temperatures and includes the low-temperature peritectoid reaction in the range near a CrNi(2) composition. Accordingly, the mixing behaviour in Al-Cr and Cr-Ni alloy melts was studied using the complex formation model in the weak interaction approximation and by postulating Al(8)Cr(5) and CrNi(2) chemical complexes, respectively, as energetically favoured.

  2. Airbreathing Propulsion Fuels and Energy Exploratory Research and Development (APFEERD) Sub Task: Review of Bulk Physical Properties of Synthesized Hydrocarbon:Kerosenes and Blends

    2017-06-01

    Fuels and Energy Branch Turbine Engine Division Turbine Engine Division CHARLES W. STEVENS, Lead Engineer Turbine Engine Division Aerospace Systems...evaluation concludes, based on fundamental physical chemistry , that all hydrocarbon kerosenes that meet the minimum density requirement will have bulk...alternative jet fuels; renewable jet fuel; fuel physical properties; fuel chemistry ; fuel properties 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF

  3. Thermal properties and modeling of aluminosilicate materials for low-temperature bulk applications

    Kaushal, S.

    1988-01-01

    This thesis concerns itself with the thermal properties of aluminosilicate materials such as cements, blended cements and clays and their application to the problem of radioactive waste encapsulation. The objective of this thesis is to study the thermal properties (heat of hydration, thermal conductivity and diffusivity) of these materials and to determine their effect on the temperature in large monoliths and on the material itself. In this thesis the hydration temperatures for the extreme conditions (adiabatic) were experimentally measured and compared to those predicted under real conditions. Such a simulation can be made by measuring the thermal properties and studying the temperature distribution predicted by a finite differences computer model. Measurements of adiabatic temperature rise were made using a computer-controlled adiabatic calorimeter which was designed and developed for this thesis. Conditions very close to zero heat exchange with the environment were achieved. The existence of this method made it possible to actually observe the fact that cement hydration results in boiling off of the water in such conditions. A number of additives were tried to prevent this. It was observed that waste or by-product materials such as blast furnace slag and fly ash could be used to dramatically reduced the temperature in large bodies. These materials also reacted extensively with the highly alkaline radioactive waste solution to form hydrogarnet and zeolitic material which had useful cementing properties. The conclusion was reached that a selection of blends of aluminosilicate materials can be utilized for providing the proper thermal environment for long-term geological disposal of radioactive waste

  4. The Surface and Bulk Magnetic Properties of Fe-Al Alloys

    Hendrych, A.; Žitovsky, O.; Jirásková, Yvonna; Matko, I.

    2014-01-01

    Roč. 126, č. 1 (2014), s. 58-59 ISSN 0587-4246. [CSMAG Czech and Slovak Conference on Magnetism /15./. Košice, 17.06.2013-21.06.2013] R&D Projects: GA MŠk 7AMB12SK009 Institutional support: RVO:68081723 Keywords : Fe-Al * MOKE * Surface properties * MFM Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.530, year: 2014

  5. Independent Control of Adhesive and Bulk Properties of Hybrid Silica Coatings on Polycarbonate

    Lionti , Krystelle; Cui , Linying; Volksen , Willi; Dauskardt , Reinhold; Dubois , Geraud; Toury , Bérangère

    2013-01-01

    International audience; Transparent polymers are widely used in many 9 applications ranging from automotive windows to micro-10 electronics packaging. However, their intrinsic characteristics, 11 in particular their mechanical properties, are significantly 12 degraded with exposure to different weather conditions. For 13 instance, under humid environment or UV-irradiation, 14 polycarbonate (PC) undergoes depolymerization, leading to 15 the release of Bisphenol A, a molecule presumed to be a 1...

  6. Mechanical Properties Transformation On Zr54Al17Co29 Bulk Metallic Glass by Partial Crystallization

    Yanuar Rohmat Aji Pradana

    2017-05-01

    Full Text Available Study on biomaterials is recently essential for rapid development of medical application and Zr54Al17Co29 BMGbecomes promising candidate due to the lack of toxic elements. Partial crystallization by isothermal annealing at SCL region was used to variate the crystallinities of BMG. The structural and thermal properties of as cast and partially crystallized samples were confirmed by XRD and DSC test, while microvickers and compression test were further utilized to investigate their mechanical properties. By the higher crystallinity, the hardness could be slightly increased in range 540 ± 5 to 575 ± 5 Hv. As-cast sample shows the yield strength and plastic strain of 2130 ± 75 MPa and 2.2 ± 1.6%. The yield strength is increased by the presence of 10% nanocrystal, afterwards, fall and raise phenomena are obtained with further crystallinity. However, with higher crystallinity, the plasticity is significantly degraded and no more plastic strain observed at sample with 50% of crystallinity. Both the presence of nanocrystalline phase and free volume annihilation are the reason of mechanical properties change on the Zr-based BMG.

  7. Electronic properties of Mn-phthalocyanine–C60 bulk heterojunctions: Combining photoemission and electron energy-loss spectroscopy

    Roth, Friedrich; Herzig, Melanie; Knupfer, Martin; Lupulescu, Cosmin; Darlatt, Erik; Gottwald, Alexander; Eberhardt, Wolfgang

    2015-01-01

    The electronic properties of co-evaporated mixtures (blends) of manganese phthalocyanine and the fullerene C 60 (MnPc:C 60 ) have been studied as a function of the concentration of the two constituents using two supplementary electron spectroscopic methods, photoemission spectroscopy (PES) and electron energy-loss spectroscopy (EELS) in transmission. Our PES measurements provide a detailed picture of the electronic structure measured with different excitation energies as well as different mixing ratios between MnPc and C 60 . Besides a relative energy shift, the occupied electronic states of the two materials remain essentially unchanged. The observed energy level alignment is different compared to that of the related CuPc:C 60 bulk heterojunction. Moreover, the results from our EELS investigations show that, despite the rather small interface interaction, the MnPc related electronic excitation spectrum changes significantly by admixing C 60 to MnPc thin films

  8. Effect of annealing on the magnetic properties of Nd70Fe20Al10 bulk metallic glasses

    Olivetti, Elena; Baricco, Marcello; Ferrara, Enzo; Tiberto, Paola; Martino, Luca

    2005-01-01

    In this work, the influence of thermal treatments on the hysteresis behaviour of Nd 70 Fe 20 Al 10 bulk metallic glasses is studied. Two samples obtained applying different quenching rates have been characterized: (a) master alloy ingots, prepared through arc melting, and (b) cone-shaped ingots obtained by copper mould casting. DSC measurements have been performed on both alloys. Selected samples have been submitted to subsequent annealing. Hard magnetic properties have been observed at room temperature either in the as-cast master alloy or in the cone-shaped ingots. High values of coercivity are still observed after treatment at temperatures close to the crystallisation temperature (up to 500 deg. C). The different magnetic behaviour of the samples is discussed in terms of differences in the residual amorphous phase composition

  9. A novel in situ device based on a bionic piezoelectric actuator to study tensile and fatigue properties of bulk materials.

    Wang, Shupeng; Zhang, Zhihui; Ren, Luquan; Zhao, Hongwei; Liang, Yunhong; Zhu, Bing

    2014-06-01

    In this work, a miniaturized device based on a bionic piezoelectric actuator was developed to investigate the static tensile and dynamic fatigue properties of bulk materials. The device mainly consists of a bionic stepping piezoelectric actuator based on wedge block clamping, a pair of grippers, and a set of precise signal test system. Tensile and fatigue examinations share a set of driving system and a set of signal test system. In situ tensile and fatigue examinations under scanning electron microscope or metallographic microscope could be carried out due to the miniaturized dimensions of the device. The structure and working principle of the device were discussed and the effects of output difference between two piezoelectric stacks on the device were theoretically analyzed. The tensile and fatigue examinations on ordinary copper were carried out using this device and its feasibility was verified through the comparison tests with a commercial tensile examination instrument.

  10. Enhanced Mechanical Properties of MgZnCa Bulk Metallic Glass Composites with Ti-Particle Dispersion

    Pei Chun Wong

    2016-05-01

    Full Text Available Rod samples of Mg60Zn35Ca5 bulk metallic glass composites (BMGCs dispersed with Ti particles have been successfully fabricated via injection casting. The glass forming ability (GFA and the mechanical properties of these Mg-based BMGCs have been systematically investigated as a function of the volume fraction (Vf of Ti particles. The results showed that the compressive ductility increased with Vf. The mechanical performance of these BMGCs, with up to 5.4% compressive failure strain and 1187 MPa fracture strength at room temperature, can be obtained for the Mg-based BMGCs with 50 vol % Ti particles, suggesting that these dispersed Ti particles can absorb the energy of the crack propagations and can induce branches of the primary shear band into multiple secondary shear bands. It follows that further propagation of the shear band is blocked, enhancing the overall plasticity.

  11. Effect of high-order multicomponent on formation and properties of Zr-based bulk glassy alloys

    Inoue, A., E-mail: ainouebmg@yahoo.co.jp [International Institute of Green Materials, Josai International University, Togane 283-8555 (Japan); School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Department of Physics, King Abdulaziz University, Jeddah 22254 (Saudi Arabia); Wang, Z.; Louzguine-Luzgin, D.V. [WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Han, Y. [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Kong, F.L. [International Institute of Green Materials, Josai International University, Togane 283-8555 (Japan); Shalaan, E.; Al-Marzouki, F. [Department of Physics, King Abdulaziz University, Jeddah 22254 (Saudi Arabia)

    2015-07-25

    Highlights: • A multicomponent Zr{sub 55}Al{sub 10}Fe{sub 6}Co{sub 6}Ni{sub 6}Cu{sub 6}Pd{sub 6}Ag{sub 5} bulk glassy alloy was formed. • The high-order multiplication suppression of the decrease in mechanical strength. • The BGAs show good corrosion resistance and slow growth rate of primary precipitates. - Abstract: We examined the formation, thermal stability, mechanical properties and corrosion behavior of a multicomponent Zr{sub 55}Al{sub 10}Fe{sub 6}Co{sub 6}Ni{sub 6}Cu{sub 6}Pd{sub 6}Ag{sub 5} bulk glassy alloy, with the aim of clarifying the effect of high-order multiplication of the number of components on their properties. The bulk glassy alloy rods of 2 and 6 mm in diameter were formed by suction casting even at the low total content of typical glass-forming 3-d late transition metals like Co, Ni and Cu. The Vickers hardness is different in the center region and in the outer surface region. The difference seems to reflect the relaxation level of glassy structure. The Young’s modulus and the compressive fracture strength are nearly the same for the base Zr{sub 55}Al{sub 10}Ni{sub 5}Cu{sub 30} alloy in spite of the existence of immiscible atomic pairs. Moreover, the multicomponent alloy exhibits better corrosion resistance than that for the base alloy. The glassy phase changes to a supercooled liquid state at 720 K and then starts to crystallize at 754 K with a single exothermic peak, in contrast to the appearance of a wide supercooled liquid region for the base alloy. The primary crystalline phase precipitates with very short incubation time and very low growth rate, which are different from those for the base alloy. The extremely low growth rate of the crystallites is presumably due to the reduction of diffusivity of late transition metal elements resulting from multiplication. Thus, the high-order multiplication has the features of (1) the maintenance of high glass-forming ability even at the lower Co, Ni and Cu content and in the absence of

  12. Emergent Low-Symmetry Phases and Large Property Enhancements in Ferroelectric KNbO 3 Bulk Crystals

    Lummen, Tom T. A. [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 USA; Leung, J. [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 USA; Kumar, Amit [School of Mathematics and Physics, Queen' s University Belfast, University Road, Belfast BT71NN Northern Ireland UK; Wu, X. [Department of Physics, University of Texas at Austin, Austin TX 78712 USA; Ren, Y. [Department of Physics, University of Texas at Austin, Austin TX 78712 USA; VanLeeuwen, Brian K. [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 USA; Haislmaier, Ryan C. [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 USA; Holt, Martin [Center for Nanoscale Materials, Argonne National Laboratory, Argonne IL 60439 USA; Lai, Keji [Department of Physics, University of Texas at Austin, Austin TX 78712 USA; Kalinin, Sergei V. [Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge TN 37831 USA; Gopalan, Venkatraman [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 USA

    2017-06-19

    The design of new or enhanced functionality in materials is traditionally viewed as requiring the discovery of new chemical compositions through synthesis. Large property enhancements may however also be hidden within already well-known materials, when their structural symmetry is deviated from equilibrium through a small local strain or field. Here, the discovery of enhanced material properties associated with a new metastable phase of monoclinic symmetry within bulk KNbO3 is reported. This phase is found to coexist with the nominal orthorhombic phase at room temperature, and is both induced by and stabilized with local strains generated by a network of ferroelectric domain walls. While the local microstructural shear strain involved is only approximate to 0.017%, the concurrent symmetry reduction results in an optical second harmonic generation response that is over 550% higher at room temperature. Moreover, the meandering walls of the low-symmetry domains also exhibit enhanced electrical conductivity on the order of 1 S m(-1). This discovery reveals a potential new route to local engineering of significant property enhancements and conductivity through symmetry lowering in ferroelectric crystals.

  13. The effect of inclusions on macroscopic composite elasticity: A systematic finite-element analysis of constituent and bulk elastic properties

    Yoneda, A; Sohag, F H

    2010-01-01

    The bulk physical properties of composite systems are difficult to predict - even when the properties of the constituent materials in the system are well known. We conducted a finite-element method simulation to examine the inclusion effect by substituting an inclusion phase (second phase) into a host phase (first phase). We have organized the simulation results as a function of the elasticity of host and inclusion phases. In this procedure, special attention was paid to the initial change of elastic constants as the inclusion volume ratio was varied. To accomplish this, we introduced a new parameter D ij defined as the derivatives of the normalized stiffness elastic constant over the inclusion volume ratio. We succeeded in obtaining useful systematic formulations for D ij . These formulations are expected to be applicable to the study of composite systems in many disciplines, such as geophysics, mechanics, material engineering, and biology. The present results provide much more effective constraints on the physical properties of composite systems, like rocks, than traditional methods, such as the Voigt-Reuss bounds.

  14. Solvent properties of hydrazine in the preparation of metal chalcogenide bulk materials and films.

    Yuan, Min; Mitzi, David B

    2009-08-21

    A combination of unique solvent properties of hydrazine enables the direct dissolution of a range of metal chalcogenides at ambient temperature, rendering this an extraordinarily simple and soft synthetic approach to prepare new metal chalcogenide-based materials. The extended metal chalcogenide parent framework is broken up during this process, and the resulting metal chalcogenide building units are re-organized into network structures (from 0D to 3D) based upon their interactions with the hydrazine/hydrazinium moieties. This Perspective will review recent crystal and materials chemistry developments within this family of compounds and will briefly discuss the utility of this approach in metal chalcogenide thin-film deposition.

  15. Tuning the Properties of Polymer Bulk Heterojunction Solar Cells by Adjusting Fullerene Size to Control Intercalation

    Cates, Nichole C.; Gysel, Roman; Beiley, Zach; Miller, Chad E.; Toney, Michael F.; Heeney, Martin; McCulloch, Iain; McGehee, Michael D.

    2009-01-01

    We demonstrate that intercalation of fullerene derivatives between the side chains of conjugated polymers can be controlled by adjusting the fullerene size and compare the properties of intercalated and nonintercalated poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (pBTTT):fullerene blends. The intercalated blends, which exhibit optimal solar-cell performance at 1:4 polymer:fullerene by weight, have better photoluminescence quenching and lower absorption than the nonintercalated blends, which optimize at 1:1. Understanding how intercalation affects performance will enable more effective design of polymer:fullerene solar cells. © 2009 American Chemical Society.

  16. Structure–property relationships of oligothiophene–isoindigo polymers for efficient bulk-heterojunction solar cells

    Ma, Zaifei; Sun, Wenjun; Himmelberger, Scott

    2014-01-01

    interfacial energy level offset ensures efficient exciton separation and charge generation. The structure–property relationship demonstrated in this work would be a valuable guideline for the design of high performance polymers with small energy losses during the charge generation process, allowing......) in the repeating unit alters both polymer crystallinity and polymer–fullerene interfacial energetics, which results in a decreasing open-circuit voltage (Voc) of the solar cells with increasing n. The short-circuit current density (Jsc) of P1TI:PCBM devices is limited by the absence of a significant driving force...

  17. Tuning the Properties of Polymer Bulk Heterojunction Solar Cells by Adjusting Fullerene Size to Control Intercalation

    Cates, Nichole C.

    2009-12-09

    We demonstrate that intercalation of fullerene derivatives between the side chains of conjugated polymers can be controlled by adjusting the fullerene size and compare the properties of intercalated and nonintercalated poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (pBTTT):fullerene blends. The intercalated blends, which exhibit optimal solar-cell performance at 1:4 polymer:fullerene by weight, have better photoluminescence quenching and lower absorption than the nonintercalated blends, which optimize at 1:1. Understanding how intercalation affects performance will enable more effective design of polymer:fullerene solar cells. © 2009 American Chemical Society.

  18. An analytical model of the mechanical properties of bulk coal under confined stress

    Wang, G.X.; Wang, Z.T.; Rudolph, V.; Massarotto, P.; Finley, R.J.

    2007-01-01

    This paper presents the development of an analytical model which can be used to relate the structural parameters of coal to its mechanical properties such as elastic modulus and Poisson's ratio under a confined stress condition. This model is developed primarily to support process modeling of coalbed methane (CBM) or CO2-enhanced CBM (ECBM) recovery from coal seam. It applied an innovative approach by which stresses acting on and strains occurring in coal are successively combined in rectangular coordinates, leading to the aggregated mechanical constants. These mechanical properties represent important information for improving CBM/ECBM simulations and incorporating within these considerations of directional permeability. The model, consisting of constitutive equations which implement a mechanically consistent stress-strains correlation, can be used as a generalized tool to study the mechanical and fluid behaviors of coal composites. An example using the model to predict the stress-strain correlation of coal under triaxial confined stress by accounting for the elastic and brittle (non-elastic) deformations is discussed. The result shows a good agreement between the prediction and the experimental measurement. ?? 2007 Elsevier Ltd. All rights reserved.

  19. Properties of unirradiated fuel element graphites H-451 and SO818. [Bulk density, tensile properties, thermal expansion, thermal conductivity

    Engle, G.B.; Johnson, W.R.

    1976-10-08

    Nuclear graphites H-451, lot 440 (Great Lakes Carbon Corporation (GLCC)), and SO818 (Airco Speer Division, Air Reduction Corporation (AS)) are described, and physical, mechanical, and chemical property data are presented for the graphites in the unirradiated state. A summary of the mean values of the property data and of data on TS-1240 and H-451, lot 426, is tabulated. A direct comparison of H-451, lot 426, chosen for Fort St. Vrain (FSV) fuel reload production, TS-1240, and SO818 may be made from the table. (auth)

  20. AC conductivity and dielectric properties of bulk tungsten trioxide (WO3)

    El-Nahass, M. M.; Ali, H. A. M.; Saadeldin, M.; Zaghllol, M.

    2012-11-01

    AC conductivity and dielectric properties of tungsten trioxide (WO3) in a pellet form were studied in the frequency range from 42 Hz to 5 MHz with a variation of temperature in the range from 303 K to 463 K. AC conductivity, σac(ω) was found to be a function of ωs where ω is the angular frequency and s is the frequency exponent. The values of s were found to be less than unity and decrease with increasing temperature, which supports the correlated barrier hopping mechanism (CBH) as the dominant mechanism for the conduction in WO3. The dielectric constant (ε‧) and dielectric loss (ε″) were measured. The Cole-Cole diagram determined complex impedance for different temperatures.

  1. Relations between structural and superconducting properties of bulk and thin film high-Tc materials

    Hessel Andersen, N.

    1994-06-01

    The structural ordering of oxygen deficient and Co-doped YBCO (YBa 2 Cu 3-y Co y O 6+x ) have been studied experimentally, and by computer simulations of the oxygen ordering in the basal plane of the structure. The calculations are based on the two-dimensional ASYNNNI model and its modifications. Good agreement is established between the ASYNNNI calculations and the experimentally observed structural properties of the double cell ortho-II structure and the oxygen disordering process from Co-doping into the basal plane. A model that relates the superconducting transition temperature T c (x) of undoped YBCO and T c (y) of Co-doped YBCO to the formation of specific domains of the two orthorhombic ordered oxygen phases, ortho-I and ortho-II, shows a close agreement with experimental T c (x) and T c (y) data of samples prepared under equilibrium conditions. The structural changes as a result of metal ion substitutions and oxidation/reduction processes have been studied by neutron powder diffraction in Pb 2 Sr 2 Ln 1-x Ca x Cu 3 O 8+y (Ln = Y and Ho), Nd 1.85 Ce 0.15 CuO 4+y , and chemically oxidized La 2-x Sr x CuO 4+y 2 Cu 3-y Al y O 6+x (y 2 Cu 3 O 6+x and Bi 2 Sr 2 CaCu 2 O 8+x thin films deposited on SrTiO 3 (001), MgO (001), LaAlO 3 (001), and NdGaO 3 (001) substrates has been studied by x-ray diffraction, TEM and RBS, and the structural ordering has been analysed in relation to their superconducting properties. (au) (30 ills., 29 refs.)

  2. Electrical properties of bulk InP synthesized by modified horizontal Bridgman method

    Pak, K.; Matsui, M.; Fukuhara, H.; Nishinaga, T.; Nakamura, T.; Yasuda, Y.

    1986-01-01

    High purity polycrystalline InP has been required for preparation of starting materials in LEC pulling. Usually, these materials are synthesized by the horizontal Bridgman (HB) or gradient freeze (GF) method. The major problem for InP synthesis has been attributed to silicon contamination during the growth, as shown by several workers. In a previous paper, the authors proposed a model in which the silicon contamination would occur due to the transport of SiO and In/sub 2/O gas species from the In-P melt to the phosphorus region by the reaction of the melt with the quartz boat in the HB growth system and suggested that the Si concentration in the In-P melt would have an intimate correlation with the temperature in the phosphorus region. However, the effect of the temperature in the phosphorus region on the electrical properties has not been studied in details as of yet. In this note, a modified horizontal Bridgman (MHB) method was developed to reduce the residual donor impurities, and the reduction mechanism is discussed

  3. 3D printed glass: surface finish and bulk properties as a function of the printing process

    Klein, Susanne; Avery, Michael P.; Richardson, Robert; Bartlett, Paul; Frei, Regina; Simske, Steven

    2015-03-01

    It is impossible to print glass directly from a melt, layer by layer. Glass is not only very sensitive to temperature gradients between different layers but also to the cooling process. To achieve a glass state the melt, has to be cooled rapidly to avoid crystallization of the material and then annealed to remove cooling induced stress. In 3D-printing of glass the objects are shaped at room temperature and then fired. The material properties of the final objects are crucially dependent on the frit size of the glass powder used during shaping, the chemical formula of the binder and the firing procedure. For frit sizes below 250 μm, we seem to find a constant volume of pores of less than 5%. Decreasing frit size leads to an increase in the number of pores which then leads to an increase of opacity. The two different binders, 2- hydroxyethyl cellulose and carboxymethylcellulose sodium salt, generate very different porosities. The porosity of samples with 2-hydroxyethyl cellulose is similar to frit-only samples, whereas carboxymethylcellulose sodium salt creates a glass foam. The surface finish is determined by the material the glass comes into contact with during firing.

  4. Impact of the structural state on the mechanical properties in a Zr–Co–Al bulk metallic glass

    Qiao, J.C.; Pelletier, J.M.; Esnouf, C.; Liu, Y.; Kato, H.

    2014-01-01

    Highlights: • Atomic mobility in metallic glass was studied by DMA, HRTEM and nanoindentation. • Physical ageing and crystallization reduce the atomic mobility. • Plastic deformation, i.e. cold-rolling enhances the atomic mobility. • Atomic mobility in glassy materials can be described by quasi-point defects model. - Abstract: This paper reports on the use of differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and nanoindentation technique to investigate atomic mobility in Zr 56 Co 28 Al 16 bulk metallic glass in the as-cast state, after thermal annealing and after cold rolling. From the DMA results together with nanoindentation data point of view, the atomic mobility is significantly modified by the thermo-mechanical history. On the one hand, atomic mobility in bulk metallic glass is reduced after physical aging or crystallization. On the other hand, the atomic mobility in metallic glass is enhanced by cold rolling. To analyze the atomic mobility in amorphous materials, a physical theory is introduced. This model invoked the concept of quasi-point defects, which correspond to the density fluctuations in the glassy materials. Correlated movements of atoms are assisted by these quasi-point defects and the correlation factor χ is connected to the concentration of these “defects” in metallic glasses: (i) physical aging and crystallization decreases the parameter χ and (ii) the concentration of defects augments via plastic deformation (i.e. cold-rolling), suggesting that the correlation factor χ reflects the atomic mobility for glassy materials in a quantitative manner. This correlation bridges the gap between the mechanical properties on macroscopic scale and atomic mobility in microstructural regions in metallic glasses

  5. Effects of Bi-2212 addition on the levitation force properties of bulk MgB2 superconductors

    Taylan Koparan, E.; Savaskan, B.; Guner, S.B.; Celik, S.

    2016-01-01

    We present a detailed investigation of the effects of Bi 2 Sr 2 Ca 1 Cu 2 O 8+κ (Bi-2212) adding on the levitation force and magnetic properties of bulk MgB 2 obtained by hot press method. The amount of Bi-2212 was varied between 0 and 10 wt% (0, 2, 4, 6, 10 wt%) of the total MgB 2 . Moreover, we present MgB 2 bulk samples fabricated by using different production methods including hot pressing method to our knowledge. All samples were prepared by using elemental magnesium (Mg) powder, amorphous nano-boron (B) powder and Bi-2212 powder which are produced by hot press method. As a result of hot press process, compact pellet samples were manufactured. The vertical and lateral levitation force measurements were executed at the temperatures of 20, 24 and 28 K under zero-field-cooled (ZFC) and field-cooled (FC) regimes for samples with various adding levels. At 24 K and 28 K under ZFC regime, the 2 wt% Bi-2212 added sample exhibits a higher vertical levitation force than the pure sample. Bi-2212 added MgB 2 samples compared to the pure sample have lower attractive force values in FC regime. The magnetic field dependence of the critical current density J c was calculated from the M-H loops for Bi-2212 added MgB 2 samples. The 2 wt% Bi-2212 added sample has the best levitation and critical current density performance compared to other samples. The critical temperature (T c ) has slightly dropped from 37.8 K for the pure MgB 2 sample to 36.7 K for the 10 wt% of Bi-2212 added sample. The transition temperature slightly decreases when Bi-2212 adding level is increased. (orig.)

  6. Effect of MoSi2 Content on Dry Sliding Tribological Properties of Zr-Based Bulk Metallic Glass Composites

    Liu, Longfei; Yang, Jun

    2017-12-01

    Zr55Cu30Al10Ni5 bulk metallic glass and its composites were prepared by suction casting into a copper mold. The effect of MoSi2 content on the tribological behavior of Zr55Cu30Al10Ni5 BMG was studied by using a high-speed reciprocating friction and wear tester. The results indicate that the friction coefficient and wear resistance of the BMGs can be improved by a certain amount of crystalline phase induced by MoSi2 content from 1 to 3% and deteriorated with MoSi2 content of 4%. The wear mechanism of both the metallic glass and its composite is abrasive wear. The mechanism of crystalline phase-dependent tribological properties of the composite was discussed based on the wear track and mechanical properties in the present work. The wear behavior of Zr55Cu30Al10Ni5 BMG and its composite indicates that a good combination of the toughness and the hardness can make the composite be well wear resistant.

  7. Microstructural evolution during the synthesis of bulk components from nanocrystalline ceramic powder, part II: microstructure and properties

    Ajaal, T. T.; Metak, A. M.

    2004-01-01

    Part I of this review, published in 5 /4th of Al-Nawah magazine, was devoted to the synthetic techniques used in the production processes of a bulk components of nanocrystalline materials. In this part, the microstructural evolution and its effect on the materials properties will be detailed. Minimizing grain growth and maximizing densification during the sintering stage of the ultrafine particles as well as the homogeneous densification in pressureless sintering, grain growth and rapid rate pressureless sintering will be discussed. Ceramics are well known for their high strength at elevated temperatures, as well as the extreme brittleness that prevents their application in many critical components. However, researchers have found that brittleness can be overcome by reducing particle sizes to nanometer levels. These fine grain structures are believed to provide improved ductility the individual grains can slide over one another without causing cracks. In addition, nanophase ceramics are more easily formed than their conventional counterparts, and easier to machine without cracking or breaking. Shrinkage during sintering is also greatly reduced in nanophase ceramics, and they can be sintered at lower temperatures than conventional ceramics. As a result, nanophase ceramics have the potential to deliver an ideal combination of ductility and high-temperature strength, allowing increased efficiency in applications ranging from automobile engines to jet aircraft. This part of the review covers the microstructural evolution during the synthetic process of nanocrystalline ceramic materials and its effects on the materials properties.(author)

  8. Transport Properties of Bulk Thermoelectrics—An International Round-Robin Study, Part I: Seebeck Coefficient and Electrical Resistivity

    Wang, Hsin; Porter, Wallace D.; Böttner, Harald; König, Jan; Chen, Lidong; Bai, Shengqiang; Tritt, Terry M.; Mayolet, Alex; Senawiratne, Jayantha; Smith, Charlene; Harris, Fred; Gilbert, Patricia; Sharp, Jeff W.; Lo, Jason; Kleinke, Holger; Kiss, Laszlo

    2013-04-01

    Recent research and development of high-temperature thermoelectric materials has demonstrated great potential for converting automobile exhaust heat directly into electricity. Thermoelectrics based on classic bismuth telluride have also started to impact the automotive industry by enhancing air-conditioning efficiency and integrated cabin climate control. In addition to engineering challenges of making reliable and efficient devices to withstand thermal and mechanical cycling, the remaining issues in thermoelectric power generation and refrigeration are mostly materials related. The dimensionless figure of merit, ZT, still needs to be improved from the current value of 1.0 to 1.5 to above 2.0 to be competitive with other alternative technologies. In the meantime, the thermoelectric community could greatly benefit from the development of international test standards, improved test methods, and better characterization tools. Internationally, thermoelectrics have been recognized by many countries as a key component for improving energy efficiency. The International Energy Agency (IEA) group under the Implementing Agreement for Advanced Materials for Transportation (AMT) identified thermoelectric materials as an important area in 2009. This paper is part I of the international round-robin testing of transport properties of bulk thermoelectrics. The main foci in part I are the measurement of two electronic transport properties: Seebeck coefficient and electrical resistivity.

  9. Properties of millimetre wave sintered and oxygenated YBa2Cu3Ox bulk material

    Hunyar, C.

    1999-12-01

    High temperature superconductors are ceramic materials whose properties strongly depend on the techniques used for their production. The successful use of microwaves for the sintering of other oxidic ceramics suggests the examination of the advantages and disadvantages of that production technique for superconductors. For this purpose pellets of commercially available YBa 2 Cu 3 O x powder from the Solvay company were pressed and sintered by millimetre wave heating (30 GHz, generated in a gyrotron). In various experiments the sintering temperatures were varied between 920 C and 990 C, and the holding times between 15 min and 240 min. The densities of the pellets were measured by the Archimedes method and the material structure was examined with an optical microscope. A strong densification from 86 to 93% of theoretical density could be observed within 30 min at a holding temperature of 960 C. With sintering temperatures above 960 C no significant increase in density occurred. At 950 C, only minor grain growth could be observed, which increased up to 960 C temperature. At higher temperatures a mixture of small grains and crystallites of about 150 μm size established itself. CuO already present in the original powder started to melt along the grain boundaries where it acts as a limiting factor for grain growth. With millimetre wave sintering the same material densities could be achieved in less than one third of the time needed for conventional sintering processes. In addition the effects of millimetre wave heating on the oxygen diffusion in YBCO were investigated with several pairs of identical samples. The pairs were deoxygenated and subsequently oxygenated in an atmosphere of pure O 2 in a conventional tube furnace and by millimetre wave heating respectively. To compare the oxygen concentration of the samples, their specific surface resistance at room temperature, which correlates with the oxygen content, was measured in a cylindrical copper resonator with

  10. Assessing the dependence of bulk ice properties from probes with anti-shatter tips on environmental conditions

    Jackson, Robert C.

    Ice clouds have significant impacts on the Earth's radiative budget. Their radiative impact highly depends on ice cloud microphysical properties. Climate and weather prediction models have to make certain assumptions about how the various processes are represented. Observations of how cloud properties vary with environmental conditions can help evaluate some parameterizations used in models. However, sufficient data are not available to characterize how ice crystal properties vary as a function of environmental conditions. Furthermore, many of these assumptions are derived from historical datasets collected by in situ probes, namely optical array probes that can be contaminated by shattered artifacts generated by large particles shattering on the probe tips and inlets. Therefore this study has two main objectives. Prior estimates of ice crystal size distributions derived from 2D Cloud Probes (2DCs) have been artificially amplified by small ice crystals generated from the shattering of large ice crystals on the probe tips. Although anti-shatter tips and algorithms exist, there is considerable uncertainty in their effectiveness. Therefore, this thesis first examines the differences in ice crystal size distributions, and bulk and optical properties from adjacent 2DCs with standard and anti-shatter tips, and processed with and without anti-shattering algorithms. The measurements were obtained from the National Research Council of Canada Convair-580 during the 2008 Indirect and Semi-Direct Aerosol Campaign (ISDAC) and the National Center for Atmospheric Research C-130 during the 2011 Instrumentation Development and Education in Airborne Science 2011 (IDEAS-2011). The 2DC size distributions are compared with those from the Holographic Detector for Clouds (HOLODEC), which has anti-shatter tips and allows for identification of shattering through spatial statistics. The ratio of the number concentration N of particles with maximum dimensions 125 to 500 mum from the 2DC with

  11. Effect of niobium on microstructure and magnetic properties of bulk anisotropic NdFeB/{alpha}-Fe nanocomposites

    Li Jun [School of Materials Science and Engineering, Sichuan University, Chengdu 610065 (China); Liu Ying, E-mail: Liuying5536@163.com [School of Materials Science and Engineering, Sichuan University, Chengdu 610065 (China) and Key Laboratory of Advanced Special Material and Technology, Ministry of Education, Chengdu 610065 (China); Ma Yilong [School of Materials Science and Engineering, Sichuan University, Chengdu 610065 (China)

    2012-07-15

    Bulk anisotropic NdFeB/{alpha}-Fe nano-composites were obtained directly from alloys of Nd{sub 11}Dy{sub 0.5}Fe{sub 82.4-x}Nb{sub x}B{sub 6.1} (x=0,0.5,1.0,1.5). High resolution transmission electron microscopy images showed the existence of Nb-rich amorphous grain boundary phase in the alloys with Nb doped. Field emission scanning electron microscope morphologies and X-ray diffraction patterns revealed the grain size and grain alignment of hot pressed and hot deformed nanocomposites. It was found that Nb could refine the grain size and grain texture in hot worked ribbons. Vibrating sample magnetometer results showed that the magnetic properties of the anisotropic nanocomposites were improved with increased Nb doping. The remanence, coercivity and maximum energy product of the bulk anisotropic Nd{sub 11}Dy{sub 0.5}Fe{sub 80.4}Nb{sub 2}B{sub 6.1} nanocomposites were 1.04 T, 563 kA/m and 146 kJ/m{sup 3}, respectively. - Highlights: Black-Right-Pointing-Pointer Nb has great influence on the microstructure and magnetic properties of (NdDy){sub 11.5}Fe{sub 82.4-x}Nb{sub x}B{sub 6.1} (x=0-2.0) nanocomposites. Black-Right-Pointing-Pointer Most of Nb atoms gather in the grain boundary to form Nb-rich amorphous intergranular phase, not NbFeB boride. Black-Right-Pointing-Pointer Furthermore, grain alignment can be prompt by the Nb-rich solid intergranular phase during deform. Black-Right-Pointing-Pointer Remanence, coercivity and (BH){sub m} of deformed (NdDy){sub 11.5}Fe{sub 80.4}Nb{sub 2}B{sub 6.1} nanocomposite is 1.04T, 563 kA/m and 146 kJ/m{sup 3} respectively. Black-Right-Pointing-Pointer This study provides an alternative method for prepare anisotropic nanocomposite direct from Nd-lean alloys with low cost.

  12. Bulk contribution to magnetotransport properties of low-defect-density Bi2Te3 topological insulator thin films

    Ngabonziza, P.; Wang, Y.; Brinkman, A.

    2018-04-01

    An important challenge in the field of topological materials is to carefully disentangle the electronic transport contribution of the topological surface states from that of the bulk. For Bi2Te3 topological insulator samples, bulk single crystals and thin films exposed to air during fabrication processes are known to be bulk conducting, with the chemical potential in the bulk conduction band. For Bi2Te3 thin films grown by molecular beam epitaxy, we combine structural characterization (transmission electron microscopy), chemical surface analysis as function of time (x-ray photoelectron spectroscopy) and magnetotransport analysis to understand the low defect density and record high bulk electron mobility once charge is doped into the bulk by surface degradation. Carrier densities and electronic mobilities extracted from the Hall effect and the quantum oscillations are consistent and reveal a large bulk carrier mobility. Because of the cylindrical shape of the bulk Fermi surface, the angle dependence of the bulk magnetoresistance oscillations is two dimensional in nature.

  13. In-pile tritium permeation experiment

    Longhurst, G.R.; Miller, L.G.; Watts, K.D.; Kershner, C.J.; Rogers, M.L.

    1982-01-01

    The experiments in progress are examining various aspects of the permeation of hydrogen isotopes through fusion materials. Of particular importance will be the measurement of permeation due to ion implantation in the presence of a neutron radiation field. Theoretical and early experimental results for these experiments have suggested that sufficient tritium will permeate fusion reactor interior structures that development of a permeation barrier will be needed. (orig.)

  14. In-pile tritium permeation experiment

    Longhurst, G.R.; Miller, L.G.; Watts, K.D. (Idaho National Engineering Lab., Idaho Falls (USA)); Kershner, C.J.; Rogers, M.L. (Monsanto Research Corp., Miamisburg, OH (USA). Mound Facility)

    The experiments in progress are examining various aspects of the permeation of hydrogen isotopes through fusion materials. Of particular importance will be the measurement of permeation due to ion implantation in the presence of a neutron radiation field. Theoretical and early experimental results for these experiments have suggested that sufficient tritium will permeate fusion reactor interior structures that development of a permeation barrier will be needed.

  15. Study of the Thermal Properties and the Fire Performance of Flame Retardant-Organic PCM in Bulk Form.

    Palacios, Anabel; De Gracia, Alvaro; Haurie, Laia; Cabeza, Luisa F; Fernández, A Inés; Barreneche, Camila

    2018-01-12

    The implementation of organic phase change materials (PCMs) in several applications such as heating and cooling or building comfort is an important target in thermal energy storage (TES). However, one of the major drawbacks of organic PCMs implementation is flammability. The addition of flame retardants to PCMs or shape-stabilized PCMs is one of the approaches to address this problem and improve their final deployment in the building material sector. In this study, the most common organic PCM, Paraffin RT-21, and fatty acids mixtures of capric acid (CA), myristic acid (MA), and palmitic acid (PA) in bulk, were tested to improve their fire reaction. Several flame retardants, such as ammonium phosphate, melamine phosphate, hydromagnesite, magnesium hydroxide, and aluminum hydroxide, were tested. The properties of the improved PCM with flame retardants were characterized by thermogravimetric analyses (TGA), the dripping test, and differential scanning calorimetry (DSC). The results for the dripping test show that fire retardancy was considerably enhanced by the addition of hydromagnesite (50 wt %) and magnesium hydroxide (50 wt %) in fatty acids mixtures. This will help the final implementation of these enhanced PCMs in building sector. The influence of the addition of flame retardants on the melting enthalpy and temperatures of PCMs has been evaluated.

  16. Study of the Thermal Properties and the Fire Performance of Flame Retardant-Organic PCM in Bulk Form

    Anabel Palacios

    2018-01-01

    Full Text Available The implementation of organic phase change materials (PCMs in several applications such as heating and cooling or building comfort is an important target in thermal energy storage (TES. However, one of the major drawbacks of organic PCMs implementation is flammability. The addition of flame retardants to PCMs or shape-stabilized PCMs is one of the approaches to address this problem and improve their final deployment in the building material sector. In this study, the most common organic PCM, Paraffin RT-21, and fatty acids mixtures of capric acid (CA, myristic acid (MA, and palmitic acid (PA in bulk, were tested to improve their fire reaction. Several flame retardants, such as ammonium phosphate, melamine phosphate, hydromagnesite, magnesium hydroxide, and aluminum hydroxide, were tested. The properties of the improved PCM with flame retardants were characterized by thermogravimetric analyses (TGA, the dripping test, and differential scanning calorimetry (DSC. The results for the dripping test show that fire retardancy was considerably enhanced by the addition of hydromagnesite (50 wt % and magnesium hydroxide (50 wt % in fatty acids mixtures. This will help the final implementation of these enhanced PCMs in building sector. The influence of the addition of flame retardants on the melting enthalpy and temperatures of PCMs has been evaluated.

  17. Study of the Thermal Properties and the Fire Performance of Flame Retardant-Organic PCM in Bulk Form

    Palacios, Anabel; De Gracia, Alvaro

    2018-01-01

    The implementation of organic phase change materials (PCMs) in several applications such as heating and cooling or building comfort is an important target in thermal energy storage (TES). However, one of the major drawbacks of organic PCMs implementation is flammability. The addition of flame retardants to PCMs or shape-stabilized PCMs is one of the approaches to address this problem and improve their final deployment in the building material sector. In this study, the most common organic PCM, Paraffin RT-21, and fatty acids mixtures of capric acid (CA), myristic acid (MA), and palmitic acid (PA) in bulk, were tested to improve their fire reaction. Several flame retardants, such as ammonium phosphate, melamine phosphate, hydromagnesite, magnesium hydroxide, and aluminum hydroxide, were tested. The properties of the improved PCM with flame retardants were characterized by thermogravimetric analyses (TGA), the dripping test, and differential scanning calorimetry (DSC). The results for the dripping test show that fire retardancy was considerably enhanced by the addition of hydromagnesite (50 wt %) and magnesium hydroxide (50 wt %) in fatty acids mixtures. This will help the final implementation of these enhanced PCMs in building sector. The influence of the addition of flame retardants on the melting enthalpy and temperatures of PCMs has been evaluated. PMID:29329212

  18. Effects of the copper content on the structural and electrical properties of Cu2ZnSnSe4 bulks

    Tsega, Moges; Dejene, F. B.; Koao, L. F.

    2016-01-01

    We have investigated the concept of defect in CuxZnSnSe4 (x=1.6-2.0) and Cuy(Zn0.9Sn1.1)Se4 (y= 1.6-2.0) bulks prepared by liquid-phase sintering at 600 °C for 2 h with soluble sintering aids of Sb2S3 and Te. All samples were found to exhibit p-type semiconductor for CuxZnSnSe4, while n-type of behavior obtained at y= 1.8-2.0 for Cuy(Zn0.9Sn1.1)Se4 pellets. The Cu vacancy acts as an acceptor point defect to form the p-type semiconductor, and Sn4+ acts as a donor to form the n-type behavior for the Sn-rich CZTSe. SEM images of pellets show dense surface morphology, and increase in grain size upon Cu inclusion. The largely increased Hall mobility and the slightly changed carrier concentration for Cuy(Zn0.9Sn1.1)Se4 with increasing the Cu content is related to the types of its defects. At y=2.0 with carrier concentration of 4.88×1017 cm-3 showed the highest mobility of around 58 cm2/V s. Based upon the proposed point defects, the CZTSe property can be consistently explained.

  19. Influence of the nuclear bulk properties and the MIT bag constant on the phase transition to the quark gluon plas

    Waldhauser, B.M.; Rischke, D.H.; Maruhn, J.A.; Stoecker, H.; Greiner, W.

    1989-01-01

    We consider the influence of the bulk properties of nuclear matter, namely the ground state incompressibility and the effective nucleon mass, and of the MIT bag constant on the phase transition from hadron matter to quark gluon plasma. It is mainly the effective nucleon mass which determines the stiffness of the equation of state and therefore also the behaviour of the phase transition curves. The energy densities in the coexistence region are found to increase for finite chemical potentials and softer equations of state up to 10 GeV/fm 3 . For small bag constants and for softer nuclear equations of state the phase boundary exhibits unusual deformations, due to the fact that the phase transition sets in already at pressures not too far from the saturation value. Although this would increase the experimental possibility to create the QGP, it is more likely that one must regard bag constants in the range of the original MIT value as not producing a realistic behaviour of the quark-hadron matter phase transition in the context of an MIT bag equation of state for the quark side. (orig.)

  20. Effect of pre-existing shear bands on the tensile mechanical properties of a bulk metallic glass

    Cao, Q.P.; Liu, J.W.; Yang, K.J.; Xu, F.; Yao, Z.Q.; Minkow, A.; Fecht, H.J.; Ivanisenko, J.; Chen, L.Y.; Wang, X.D.; Qu, S.X.; Jiang, J.Z.

    2010-01-01

    Bulk Zr 64.13 Cu 15.75 Ni 10.12 Al 10 metallic glass has been rolled at room temperature in two different directions, and the dependences of microstructure and tensile mechanical property on the degree of deformation and rolling directions have been investigated. No deformation-induced crystallization occurs except for shear bands. Shear band formation in conjugated directions is achieved in the specimen rolled in two directions, while rolling in one direction induces shear band formation only in a single direction. Pre-existing properly spaced soft inhomogeneities can stabilize shear bands and lead to tensile plastic strain, and the efficient intersection of shear bands in conjugated directions results in work-hardening behavior, which is further confirmed by in situ tensile scanning electron microscopic observation. Based on the experimental results obtained in two different specimen geometries and finite element analysis, it is deduced that a normal-stress-modified maximum shear stress criterion rather than a shear plane criterion can describe the conditions for the formation of shear bands in uniaxial tension.

  1. Electrical and magnetic properties of Fe-based bulk metallic glass with minor Co and Ni addition

    Jung, H.Y. [IFW Dresden, Institute for Complex Materials, D–01069 Dresden (Germany); Stoica, M. [IFW Dresden, Institute for Complex Materials, D–01069 Dresden (Germany); POLITEHNICA University of Timisoara, P-ta Victoriei 2, Timisoara (Romania); Yi, S. [Department of Materials Science and Metallurgical Engineering, Kyungpook National University, 702–701 Daegu (Korea, Republic of); Kim, D.H. [Center for Non-crystalline Materials, Department of Metallurgical Engineering, Yonsei University, 120–749 Seoul (Korea, Republic of); Eckert, J. [IFW Dresden, Institute for Complex Materials, D–01069 Dresden (Germany); University of Technology Dresden, Institute of Materials Science, D–01062 Dresden (Germany)

    2014-09-01

    The effect of minor Co and Ni alloying on soft magnetic properties and electrical resistivity of Fe{sub 75.5}C{sub 7.0}Si{sub 3.3}B{sub 5.5}P{sub 8.7} (at%) bulk metallic glass has been investigated. Within examined compositional range (Co and Ni up to 4 at%, respectively), the saturation magnetization and electrical resistivity of the alloys continuously decrease with increasing Co or Ni content, while the Curie temperature and initial permeability increase. Comparing the effect of Co and Ni additions, the alloys with Co addition have much higher Curie temperature and saturation magnetization than the alloy with Ni addition. Also, the Co-added alloys show smaller coercivity and larger permeability than the Ni-added alloys. The present results suggest that minor addition of Co can provide better effectiveness to enhance the magnetic softness of Fe-based BMGs than minor Ni addition. - Highlights: • Soft magnetic characteristics of CI-based BMGs can be enhanced with minor Co and Ni alloying. • Minor Co addition can provide better effectiveness to enhance the magnetic softness of CI-based BMG than Ni addition. • Optimum Co addition enlarges atomic packing density and randomness of amorphous structure.

  2. First results on the charge collection properties of segmented detectors made with p-type bulk silicon

    Casse, G.; Allport, P.P.; Bowcock, T.J.V.; Greenall, A.; Hanlon, M.; Jackson, J.N.

    2002-01-01

    Radiation damage of n-type bulk detectors introduces stable defects acting as effective p-type doping and leads to the change of the conductivity type of the silicon substrate (type inversion) after a fluence of a few times 10 13 protons cm -2 . The diode junction after inversion migrates from the original side to the back plane of the detector. The migration of the junction can be prevented using silicon detectors with p-type substrates. Furthermore, the use of n-side readout gives higher charge collection efficiency for segmented devices operated below the full depletion voltage. Large area (∼6.4x6.4 cm 2 ) capacitively coupled 80 μm pitch detectors using polysilicon bias resistors have been fabricated on p-type substrates (n-in-p diode structure). These detectors have been irradiated with 24 GeV/c protons to an integrated fluence of 3x10 14 cm -2 and kept for 7 days at 25 deg. C to reach the broad minimum of the annealing curve. Results are presented on the comparison of their charge collection properties with detectors using p-strip read-out after corresponding dose and annealing

  3. Towards a unified model of passive drug permeation I: origins of the unstirred water layer with applications to ionic permeation.

    Ghosh, Avijit; Scott, Dennis O; Maurer, Tristan S

    2014-02-14

    In this work, we provide a unified theoretical framework describing how drug molecules can permeate across membranes in neutral and ionized forms for unstirred in vitro systems. The analysis provides a self-consistent basis for the origin of the unstirred water layer (UWL) within the Nernst-Planck framework in the fully unstirred limit and further provides an accounting mechanism based simply on the bulk aqueous solvent diffusion constant of the drug molecule. Our framework makes no new assumptions about the underlying physics of molecular permeation. We hold simply that Nernst-Planck is a reasonable approximation at low concentrations and all physical systems must conserve mass. The applicability of the derived framework has been examined both with respect to the effect of stirring and externally applied voltages to measured permeability. The analysis contains data for 9 compounds extracted from the literature representing a range of permeabilities and aqueous diffusion coefficients. Applicability with respect to ionized permeation is examined using literature data for the permanently charged cation, crystal violet, providing a basis for the underlying mechanism for ionized drug permeation for this molecule as being due to mobile counter-current flow. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Hydrogen permeation preventive structural materials

    Fukushima, Kimichika; Nakahigashi, Shigeo; Imura, Masashi; Terasawa, Michitaka; Ebisawa, Katsuyuki.

    1986-01-01

    Purpose: To provide highly practical wall materials for use in thermonuclear reactors capable of effectively preventing the permeation of hydrogen isotopes such as tritium thereby preventing the contamination of coolants. Constitution: Helium gas is injected into or at the surface of base materials comprising stainless steel plates to form a helium gas region. Alternatively, boron, nitrogen or the compound thereof having a greater helium forming nuclear reaction cross section than that of the base materials is mixed or injected into the base material to form the helium gas region through (n,α) reaction under neutron irradiation. Since the helium gas region constitutes a diffusion barrier for the tritium as the hydrogen isotope, the permeation amount of tritium is significantly suppressed. Helium gas bubbles or lattice defects are formed in the helium gas region under the neutron irradiation, by which the hydrogen isotope capturing effect can also be effected. In this way, permeation of the hydrogen isotope, contamination of the coolants, etc. can be prevented to provide great practical effectives. (Kawakami, Y.)

  5. Impact of Bulk Aggregation on the Electronic Structure of Streptocyanines: Implications for the Solid-State Nonlinear Optical Properties and All-Optical Switching Applications

    Gieseking, Rebecca L.

    2014-10-16

    Polymethine dyes in dilute solutions show many of the electronic and optical properties required for all-optical switching applications. However, in the form of thin films, their aggregation and interactions with counterions do generally strongly limit their utility. Here, we present a theoretical approach combining molecular-dynamics simulations and quantum-chemical calculations to describe the bulk molecular packing of streptocyanines (taken as representative of simple polymethines) with counterions of different hardness (Cl and BPh4 ) and understand the impact on the optical properties. The accuracy of the force field we use is verified by reproducing experimental crystal parameters as well as the configurations of polymethine/counterion complexes obtained from electronic-structure calculations. The aggregation characteristics can be understood in terms of both polymethinecounterion and polymethinepolymethine interactions. The counterions are found to localize near one end of the streptocyanine backbones, and the streptocyanines form a broad range of aggregates with significant electronic couplings between neighboring molecules. As a consequence, the linear and nonlinear optical properties are substantially modified in the bulk. By providing an understanding of the relationship between the molecular interactions and the bulk optical properties, our results point to a clear strategy for designing polymethine and counterion molecular structures and optimizing the materials properties for all-optical switching applications.

  6. Impact of Bulk Aggregation on the Electronic Structure of Streptocyanines: Implications for the Solid-State Nonlinear Optical Properties and All-Optical Switching Applications

    Gieseking, Rebecca L.; Mukhopadhyay, Sukrit; Shiring, Stephen B.; Risko, Chad; Bredas, Jean-Luc

    2014-01-01

    Polymethine dyes in dilute solutions show many of the electronic and optical properties required for all-optical switching applications. However, in the form of thin films, their aggregation and interactions with counterions do generally strongly limit their utility. Here, we present a theoretical approach combining molecular-dynamics simulations and quantum-chemical calculations to describe the bulk molecular packing of streptocyanines (taken as representative of simple polymethines) with counterions of different hardness (Cl and BPh4 ) and understand the impact on the optical properties. The accuracy of the force field we use is verified by reproducing experimental crystal parameters as well as the configurations of polymethine/counterion complexes obtained from electronic-structure calculations. The aggregation characteristics can be understood in terms of both polymethinecounterion and polymethinepolymethine interactions. The counterions are found to localize near one end of the streptocyanine backbones, and the streptocyanines form a broad range of aggregates with significant electronic couplings between neighboring molecules. As a consequence, the linear and nonlinear optical properties are substantially modified in the bulk. By providing an understanding of the relationship between the molecular interactions and the bulk optical properties, our results point to a clear strategy for designing polymethine and counterion molecular structures and optimizing the materials properties for all-optical switching applications.

  7. Deuterium permeation through Flibe facing materials

    Fukada, S.; Anderl, R.A.; Smolik, G.R.

    2004-01-01

    Experiment of deuterium permeation through Ni facing with purified Flibe is being carried out under the Japan-US joint research project (JUPITER-II). The experiment has been proceeding in the following phases; (i) fabrication and assembly of a dual-probe permeation apparatus, (ii) a single-probe Ni/D 2 , permeation experiment without Flibe, (iii) a dual-probe Ar/Ni/D 2 permeation experiment without Flibe, (iv) Flibe chemical purification by HF/H 2 gas bubbling, (v) physical purification by Flibe transport through a porous Ni filter, (vi) Ar/Ni/Flibe/Ni/D 2 permeation experiment using the dual Ni probe, and (vii) Ar/Ni/Flibe/Ni/HT permeation experiment. The present paper describe results until the Ar/Ni/Flibe/Ni/D 2 permeation experiment in detail. (author)

  8. Structural and magnetic properties of rapidly quenched and as-cast bulk NdFeBCu alloys

    Sanchez Ll, J.L.; Bustamante S, R.; Barthem, V.M.T.S.; Miranda, P.E.V. de

    2005-01-01

    A study of the structural and magnetic properties of as-cast and melt spun (x)Nd 2 Fe 14 B(100-x)Nd 70 Cu 30 alloys (x=10, 50 and 75%wt.) is presented. In as-cast alloys for x=10wt%. the formation of a high coercivity phase, referred to as N (T C =240 deg. C, i H C =4.9kOe) is found. N is a (Nd-Fe)-based phase with a Fe/Nd ratio lower than that of phase Nd 2 Fe 14 B (φ). It is suggested that this phase is related to the A 1 phase found in binary Nd-Fe alloys. In melt-spun alloys, at the same x value of 10wt%, another hard phase is found which is suggested to be the Nd 6 Fe 13 Cu δ-phase (T C =192 deg. C, i H C =4.8kOe). Transmission electron microscope (TEM) micrographs of the ribbons with x=10wt% shows the formation of nanograins with a non-uniform grain size distribution. In cast alloys with x=50 and 75wt% large slab-like grains of φ are formed, in the inter-granular region a Nd-Cu eutectic phase and Nd grains, are observed. High coercivities are obtained in ribbons with x=50wt% ( i H C =19.7kOe) and 75wt% ( i H C =13.0kOe). A slight reduction in the Curie temperature of the φ-phase with respect to the bulk value is found in these ribbons

  9. Effect of Si addition on glass-forming ability and mechanical properties of Cu-Zr-Al bulk metallic glass

    Malekan, M.; Shabestari, S.G.; Zhang, W.; Seyedein, S.H.; Gholamipour, R.; Makino, A.; Inoue, A.

    2010-01-01

    Research highlights: The Cu 50 Zr 43 Al 7 alloy has a surprising GFA, and the glassy rods with diameter of 10 mm have been produced in this research. It has not been reported that the Cu-based glassy rods (Cu ≥ 50 at.%) to be produced with the critical diameter greater than 10 mm. The novelty of this research is that the glass formation has been improved and the critical diameter increased to 12 mm for the alloy having x = 1 with the addition of Si. Different criteria are used to evaluate the influence of Si content on the GFA, and the possible mechanisms involved in the achievement of this GFA are also discussed. - Abstract: The effect of Si addition on the glass-forming ability (GFA) and mechanical properties of (Cu 50 Zr 43 Al 7 ) 100-x Si x (x = 0, 0.5, 1, 1.5 and 2 at.%) alloys were investigated. The GFA of Cu 50 Zr 43 Al 7 alloy is improved by addition of a small amount of Si, and the critical diameter for glass formation increases from 10 mm for the alloy with x = 0-12 mm for the alloy with x = 1 when prepared using copper mold casting. Different criteria are used to evaluate the influence of Si content on the GFA, and the possible mechanisms involved in the achievement of this GFA are also discussed. In the uniaxial compression, the bulk glassy alloys exhibit a limited plastic strain of less than 1%, but the compressive fracture strength and Young's modulus were obtained in high values of 1969-2129 MPa and 101-144 GPa, respectively. Fracture surface and shear bands of samples were studied by using scanning electron microscopy (SEM).

  10. Influence of Size on the Microstructure and Mechanical Properties of an AISI 304L Stainless Steel—A Comparison between Bulk and Fibers

    Francisco J. Baldenebro-Lopez

    2015-01-01

    Full Text Available In this work, the mechanical properties and microstructural features of an AISI 304L stainless steel in two presentations, bulk and fibers, were systematically studied in order to establish the relationship among microstructure, mechanical properties, manufacturing process and effect on sample size. The microstructure was analyzed by XRD, SEM and TEM techniques. The strength, Young’s modulus and elongation of the samples were determined by tensile tests, while the hardness was measured by Vickers microhardness and nanoindentation tests. The materials have been observed to possess different mechanical and microstructural properties, which are compared and discussed.

  11. Facile and cost-effective preparation of PVA/modified calcium carbonate nanocomposites via ultrasonic irradiation: Application in adsorption of heavy metal and oxygen permeation property.

    Mallakpour, Shadpour; Khadem, Elham

    2017-11-01

    This work is focused on the fabrication and determination of physicochemical behaviors of new poly(vinyl alcohol) (PVA) nanocomposites (NCs) containing various contents of calcium carbonate (CC) nanoparticles modified with γ-aminopropyl triethoxy silane (ATS) (henceforth designated as CC-ATS) which could be a crucial treatment for their application as gas barrier to O 2 gas and uptake of metal ions in waste waters. Samples were produced through the solution casting method under ultrasound irradiation. Thermal and mechanical performances were also evaluated for all ultrasonically synthesized nanocomposites and the results indicated that thermal and mechanical stability are dramatically enhanced by addition of a small amount of modified CC-ATS within PVA up to 5wt% and higher amounts has low effect on the composite properties. The result of oxygen gas permeability of PVA showed a 25.44% reduction by adding of 5wt% of CC-ATS into polymer matrix. Experimental adsorption isotherm data indicated that PVA NC has more efficiency for Cu(II) adsorption relative to pure PVA and well simulated by Langmuir model with maximum adsorption capacity of 45.45mgg -1 . Moreover, study of sorption kinetic indicated that the solute adsorption on PVA/CC-ATS NC 5wt% was well modeled using the pseudo-second-order. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Permeation behavior of deuterium implanted into beryllium

    Nakamura, Hirofumi; Hayashi, Takumi; O' hira, Shigeru; Nishi, Masataka [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-09-01

    Study on Implantation Driven Permeation (IDP) behavior of deuterium through pure beryllium was investigated as a part of the research to predict the tritium permeation through the first wall components ITER (International Thermonuclear Experimental Reactor). The permeation experiments were carried out with two beryllium specimens, one was an unannealed specimen and the other was that annealed at 1173 K. The permeation flux was measured as a function of specimen temperature and incident ion flux. Surface analysis of specimen was also carried out after the permeation experiment. Permeation was observed only with the annealed specimen and no significant permeation was observed with unannealed specimen under the present experimental condition (maximum temperature: 685 K, detection limit: 1x10{sup 13} D atoms/m{sup 2}s). It could be attributed that the intrinsic lattice defects, which act as diffusion preventing site, decreased with the specimen annealing. Based on the result of steady and transient permeation behavior and surface analysis, it was estimated that the deuterium permeation implanted into annealed beryllium was controlled by surface recombination due to the oxide layer on the surface of the permeated side. (author)

  13. Hydrogen permeation through metallic foils

    Bernardi, M.I.B.; Rodrigues, J.A.

    1987-01-01

    The process of electrolytic permeation of hydrogen through metallic foils is studied. A double electrolytic cell, in glass, in which the two compartments of reaction are separated by a metallic foil to be studied, was built. As direct result, the hydrogen diffusion coefficient in the metal is obtained. The hydrogen diffusion coefficients in the palladium and, in austenitic stainless steels 304 and 304 L, used in the Angra-1 reactor, were obtained. Samples of stainless steels with and without welding, were used. (Author) [pt

  14. Water vapor permeation and dehumidification performance of poly(vinyl alcohol)/lithium chloride composite membranes

    Bui, Duc Thuan; Nida, Aqdas; Ng, Kim  Choon; Chua, Kian  Jon

    2015-01-01

    were observed for membranes with increased lithium chloride content up to 50%. The permeation and sorption properties of the membranes were investigated under different temperatures. The results provided a deeper insight into the membrane water vapor

  15. Elastic properties of Pd40Cu30Ni10P20 bulk glass in supercooled liquid region

    Nishiyama, N.; Inoue, A.; Jiang, Jianzhong

    2001-01-01

    In situ ultrasonic measurements for the Pd40Cu30Ni10P20 bulk glass in three states: Glassy solid, supercooled liquid, and crystalline, have been performed. It is found that velocities of both longitudinal and transverse waves and elastic moduli (shear modulus, bulk modulus, Young's modulus......, and Lame parameter), together with Debye temperature, gradually decrease with increasing temperature through the glass transition temperature as the Poisson's ratio increases. The behavior of the velocity of transverse wave vs. temperature in the supercooled liquid region could be explained by viscosity...

  16. Tritium permeation in fusion reactors: INTOR

    Baskes, M.I.; Bauer, W.; Kerst, R.A.; Swansiger, W.A.; Wilson, K.L.

    1981-12-01

    Tritium permeation through the first wall of advanced fusion reactors is examined. A fraction of the D-T which bombards the first wall as charge exchange neutral particles will permeate through the first wall and enter the coolant. Calculations of the steady state permeation rate for the US INTOR Tokamak design result in values of less than or equal to 0.002 grams of tritium per day under the most favorable conditions. For unfavorable surface conditions the rate is greater than or equal to 0.1 g/day. The magnitude of these permeation rates is critically dependent on the temperatures and surface conditions of the wall. The introduction of permeation barriers at the wall-coolant interface can significantly reduce permeation rates and hence may be desirable for reactor applications

  17. Comparisons of Soil Properties, Enzyme Activities and Microbial Communities in Heavy Metal Contaminated Bulk and Rhizosphere Soils of Robinia pseudoacacia L. in the Northern Foot of Qinling Mountain

    Yurong Yang

    2017-11-01

    Full Text Available The toxic effects of heavy metal (HM contamination on plant metabolism and soil microorganisms have been emphasized recently; however, little is known about the differences in soil physical, chemical, and biological properties between bulk and rhizosphere soils contaminated with HMs in forest ecosystem. The present study was conducted to evaluate the rhizosphere effect on soil properties, enzyme activities and bacterial communities associated with Robinia pseudoacacia L. along a HM contamination gradient. Soil organic matter (SOM, available nitrogen (AN and phosphorus (AP contents were significantly higher in rhizosphere soil than those in bulk soil at HM contaminated sites (p < 0.05. Compared to bulk soil, activities of four soil enzymes indicative of C cycle (β-glucosidase, N cycle (protease, urease and P cycle (alkaline phosphatase in rhizosphere soil across all study sites increased by 47.5%, 64.1%, 52.9% and 103.8%, respectively. Quantitative PCR (qPCR and restriction fragment length polymorphism (RFLP were used to determine the relative abundance, composition and diversity of bacteria in both bulk and rhizosphere soils, respectively. The copy number of bacterial 16S rRNA gene in bulk soil was significantly lower than that in rhizosphere soil (p < 0.05, and it had significantly negative correlations with total/DTPA-extractable Pb concentrations (p < 0.01. Alphaproteobacteria, Gammaproteobacteria and Firmicutes were the most dominant groups of bacteria at different study sites. The bacterial diversity index of Species richness (S and Margalef (dMa were significantly higher in rhizosphere soil compared with those in bulk soil, although no difference could be found in Simpson index (D between bulk and rhizosphere soils (p > 0.05. Redundancy analysis (RDA results showed that soil pH, EC, SOM and total/DTPA-extractable Pb concentrations were the most important variables affecting relative abundance, composition and diversity of bacteria (p < 0

  18. Optical and electronic properties of 2 H -Mo S2 under pressure: Revealing the spin-polarized nature of bulk electronic bands

    Brotons-Gisbert, Mauro; Segura, Alfredo; Robles, Roberto; Canadell, Enric; Ordejón, Pablo; Sánchez-Royo, Juan F.

    2018-05-01

    Monolayers of transition-metal dichalcogenide semiconductors present spin-valley locked electronic bands, a property with applications in valleytronics and spintronics that is usually believed to be absent in their centrosymmetric (as the bilayer or bulk) counterparts. Here we show that bulk 2 H -Mo S2 hides a spin-polarized nature of states determining its direct band gap, with the spin sequence of valence and conduction bands expected for its single layer. This relevant finding is attained by investigating the behavior of the binding energy of A and B excitons under high pressure, by means of absorption measurements and density-functional-theory calculations. These results raise an unusual situation in which bright and dark exciton degeneracy is naturally broken in a centrosymmetric material. Additionally, the phonon-assisted scattering process of excitons has been studied by analyzing the pressure dependence of the linewidth of discrete excitons observed at the absorption coefficient edge of 2 H -Mo S2 . Also, the pressure dependence of the indirect optical transitions of bulk 2 H -Mo S2 has been analyzed by absorption measurements and density-functional-theory calculations. These results reflect a progressive closure of the indirect band gap as pressure increases, indicating that metallization of bulk Mo S2 may occur at pressures higher than 26 GPa.

  19. Differences in photoluminescence properties and thermal degradation between nanoparticle and bulk particle BaMgAl10O17:Eu2+ phosphors under UV?VUV irradiation.

    Liu, Bitao; Xin, Shuangyu; Li, Fenghua; Zhang, Jiachi; Wang, Yuhua

    2014-05-01

    BaMgAl10O17:Eu2+ (BAM) phosphors used for plasma display panels and three-band fluorescence lamps are exposed to an oxidizing environment at about 500 degrees C, which is currently unavoidable in actual applications. We investigated the mechanism of the luminance degradation of BAM caused by annealing at 500 degrees C based on the difference in luminance degradation of bulk particle and nanoparticle samples under various excitation source irradiations. When the samples were excited by the different light sources, more than 30% degradation of luminance occurred under 147 nm while less than 10% degradation occurred under 254 nm both for nanoparticle and bulk particle samples. In addition, the luminescence degradation of nanophosphors shows a different tendency compared to the bulk phosphors. With a model based on the particle size and excitation light penetration depth, we demonstrate that the degradation is still mainly ascribed to the oxidized of divalent Eu. The differences in luminescence properties between nanophosphors and bulk phosphors are also illustrated by this model. As a result, the potential industrial applications of nanophosphors are evaluated.

  20. Water permeation through anion exchange membranes

    Luo, Xiaoyan; Wright, Andrew; Weissbach, Thomas; Holdcroft, Steven

    2018-01-01

    An understanding of water permeation through solid polymer electrolyte (SPE) membranes is crucial to offset the unbalanced water activity within SPE fuel cells. We examine water permeation through an emerging class of anion exchange membranes, hexamethyl-p-terphenyl poly (dimethylbenzimidazolium) (HMT-PMBI), and compare it against series of membrane thickness for a commercial anion exchange membrane (AEM), Fumapem® FAA-3, and a series of proton exchange membranes, Nafion®. The HMT-PMBI membrane is found to possess higher water permeabilities than Fumapem® FAA-3 and comparable permeability than Nafion (H+). By measuring water permeation through membranes of different thicknesses, we are able to decouple, for the first time, internal and interfacial water permeation resistances through anion exchange membranes. Permeation resistances on liquid/membrane interface is found to be negligible compared to that for vapor/membrane for both series of AEMs. Correspondingly, the resistance of liquid water permeation is found to be one order of magnitude smaller compared to that of vapor water permeation. HMT-PMBI possesses larger effective internal water permeation coefficient than both Fumapem® FAA-3 and Nafion® membranes (60 and 18% larger, respectively). In contrast, the effective interfacial permeation coefficient of HMT-PMBI is found to be similar to Fumapem® (±5%) but smaller than Nafion®(H+) (by 14%).

  1. Mechanical properties of Zr41.2Ti13.8Ni10Cu12.5Be22.5 bulk metallic glass with different geometric confinements

    Zhang, Changqin; Zhang, Haifeng; Sun, Qilei; Liu, Kegao

    2018-03-01

    Zr41.2Ti13.8Ni10Cu12.5Be22.5 (Vit 1) bulk metallic glass with Cu sleeves at different positions was prepared by the Cu mold casting method, and the effects of different geometric confinements offered by Cu sleeves on the mechanical properties of Vit 1 were investigated. It was found that the mechanical properties were prominently influenced by different geometric confinements and the plasticity could be modified by optimizing the positions of Cu sleeves. The results revealed that shear band initiation and propagation could be efficiently intervened by changing the radial boundary restraints, which led to quite different mechanical behaviors.

  2. Preparation of Silica Nanoparticles Loaded with Nootropics and Their In Vivo Permeation through Blood-Brain Barrier

    Jampilek, Josef; Zaruba, Kamil; Oravec, Michal; Kunes, Martin; Babula, Petr; Ulbrich, Pavel; Brezaniova, Ingrid; Opatrilova, Radka; Triska, Jan; Suchy, Pavel

    2015-01-01

    The blood-brain barrier prevents the passage of many drugs that target the central nervous system. This paper presents the preparation and characterization of silica-based nanocarriers loaded with piracetam, pentoxifylline, and pyridoxine (drugs from the class of nootropics), which are designed to enhance the permeation of the drugs from the circulatory system through the blood-brain barrier. Their permeation was compared with non-nanoparticle drug substances (bulk materials) by means of an i...

  3. Hydrogen ion-driven permeation in carbonaceous films

    Anderl, R.A.; Holland, D.F.; Longhurst, G.R.

    1989-01-01

    This paper presents the results of investigations into the permeation properties of amorphous carbonaceous, a-C:H, films produced by plasmachemical deposition techniques. Carbonaceous films on iron substrates with thickness ranging from 60 nm to 110 nm were subjected to high fluence implantations with mass analyzed D 3 + ions with energies ranging from 600 eV to 3000 eV and fluxes ranging from 5x10 14 D/cm 2 s to 5x10 15 D/cm 2 s, respectively. Deuterium re-emission upstream, deuterium permeation downstream and secondary ions sputtered from the implantation surface were measured as a function of implantation fluence for specimens at 420 K. The present studies indicate that the a-C:H film permeability is directly related to the time, hence the fluence, required to achieve isotopic replacement and saturation of the deuterium ion beam atoms stopped in the implant region. Once the deuterium saturation level is achieved in the layer, a significant fraction of the implanting ions can result in permeation. For the present experiment, this permeation factor was much higher than that for uncoated iron specimens subjected to similar beam conditions. Carbon sputter yields of 0.008-0.01 C/D were determined in this work for 1000-eV to 400-eV deuterium ions incident on a-C:H films. (orig.)

  4. Hydrogen ion-driven permeation in carbonaceous films

    Anderl, R.A.; Holland, D.F.; Longhurst, G.R.

    1989-04-01

    This paper presents the results of investigations into the permeation properties of amorphous carbonaceous, a-C:H, films produced by plasmachemical deposition techniques. Carbonaceous films on iron substrates with thickness ranging from 60 nm to 110 nm were subjected to high fluence implantations with mass analyzed D/sub 3//sup +/ ions with energies ranging from 600 eV to 3000 eV and fluxes ranging from 5x10/sup 14/ D/cm/sup 2/ s to 5x10/sup 15/ D/cm/sup 2/ s, respectively. Deuterium re-emission upstream, deuterium permeation downstream and secondary ions sputtered from the implantation surface were measured as a function of implantation fluence for specimens at 420 K. The present studies indicate that the a-C:H film permeability is directly related to the time, hence the fluence, required to achieve isotopic replacement and saturation of the deuterium ion beam atoms stopped in the implant region. Once the deuterium saturation level is achieved in the layer, a significant fraction of the implanting ions can result in permeation. For the present experiment, this permeation factor was much higher than that for uncoated iron specimens subjected to similar beam conditions. Carbon sputter yields of 0.008-0.01 C/D were determined in this work for 1000-eV to 400-eV deuterium ions incident on a-C:H films. (orig.).

  5. Hydrogen ion-driven permeation in carbonaceous films

    Anderl, R. A.; Holland, D. F.; Longhurst, G. R.

    1989-04-01

    This paper presents the results of investigations into the permeation properties of amorphous carbonaceous, a-C: H, films produced by plasmachemical deposition techniques. Carbonaceous films on iron substrates with thickness ranging from 60 nm to 110 nm were subjected to high fluence implantations with mass analyzed D +3 ions with energies ranging from 600 eV to 3000 eV and fluxes ranging from 5 × 10 14D/ cm2 s to 5 × 10 15D/ cm2 s, respectively. Deuterium re-emission upstream, deuterium permeation downstream and secondary ions sputtered from the implantation surface were measured as a function of implantation fluence for specimens at 420 K. The present studies indicate that the a-C : H film permeability is directly related to the time, hence the fluence, required to achieve isotopic replacement and saturation of the deuterium ion beam atoms stopped in the implant region. Once the deuterium saturation level is achieved in the layer, a significant fraction of the implanting ions can result in permeation. For the present experiment, this permeation factor was much higher than that for uncoated iron specimens subjected to similar beam conditions. Carbon sputter yields of 0.008-0.01 C/D were determined in this work for 1000-eV to 400-eV deuterium ions incident on a-C : H films.

  6. Assessment of permeation of lipoproteins in human carotid tissue

    Ghosn, Mohamad G.; Syed, Saba H.; Leba, Michael; Morrisett, Joel D.; Tuchin, Valery V.; Larin, Kirill V.

    2010-02-01

    Cardiovascular disease is among the leading causes of death in the United States. Specifically, atherosclerosis is an increasingly devastating contributor to the tally and has been found to be a byproduct of arterial permeability irregularities in regards to lipoprotein penetration. To further explore arterial physiology and molecular transport, the imaging technique of Optical Coherence Tomography (OCT) was employed. With OCT, the permeation of glucose (MW = 180 Da), low density lipoprotein (LDL; MW = 2.1 × 106 Da), and high density lipoprotein (HDL; MW = 2.5 × 105 Da) in human carotid tissue was studied to determine the effect of different molecular characteristics on permeation in atherosclerotic tissues. The permeability rates calculated from the diffusion of the molecular agents into the abnormal carotid tissue samples is compared to those of normal, healthy tissue. The results show that in the abnormal tissue, the permeation of agents correlate to the size constraints. The larger molecules of LDL diffuse the slowest, while the smallest molecules of glucose diffuse the fastest. However, in normal tissue, LDL permeates at a faster rate than the other two agents, implying the existence of a transport mechanism that facilitates the passage of LDL molecules. These results highlight the capability of OCT as a sensitive and specific imaging technique as well as provide significant information to the understanding of atherosclerosis and its effect on tissue properties.

  7. Preparation by Poly(Acrylic Acid) Sol-Gel Method and Thermoelectric Properties of γ-Na x CoO2 Bulk Materials

    Li, Xiaoyu; Zhang, Li; Tang, Xinfeng

    2017-11-01

    γ-Na x CoO2 single-phase powders have been synthesized by a poly(acrylic acid) (PAA) sol-gel (SG) method, and γ-Na x CoO2 bulk ceramic fabricated using spark plasma sintering. The effects of the PAA concentration on the sample phase composition and morphology were investigated. The thermoelectric properties of the γ-Na x CoO2 bulk ceramic were also studied. The results show that the PAA concentration did not significantly affect the crystalline phase of the product. However, agglomeration of γ-Na x CoO2 crystals was suppressed by the steric effect of PAA. The Na x CoO2 bulk ceramic obtained using the PAA SG method had higher crystallographic anisotropy, better chemical homogeneity, and higher density than the sample obtained by solid-state reaction (SSR), leading to improved thermoelectric performance. The PAA SG sample had power factor (in-plane PF = σS 2) of 0.61 mW m-1 K-2 and dimensionless figure of merit ( ZT) along the in-plane direction of 0.19 at 900 K, higher than for the SSR sample (in-plane PF = 0.51 mW m-1 K-2, in-plane ZT = 0.17). These results demonstrate that a simple and feasible PAA SG method can be used for synthesis of Na x CoO2 ceramics with improved thermoelectric properties.

  8. Effects of Cu substitution for Fe on the glass-forming ability and soft magnetic properties for Fe-based bulk metallic glasses

    Dou, Lintao; Liu, Haishun; Hou, Long; Xue, Lin; Yang, Weiming; Zhao, Yucheng; Chang, Chuntao

    2014-01-01

    The effects of Cu substitution for Fe on the glass-forming ability (GFA) and soft magnetic properties for Fe 72−x Cu x B 20 Si 4 Nb 4 (x=0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) bulk metallic glasses (BMGs) are investigated. It is found that the investigated BMGs exhibit large GFA as well as excellent soft magnetic properties, and proper substitution of Fe by Cu improves the saturation magnetization, coercive force, and effective permeability without obvious deterioration of the GFA. - Highlights: • Fully glassy rods of Fe 72−x Cu x B 20 Si 4 Nb 4 BMGs were produced above 1 mm in diameter. • Investigated BMGs exhibit large glass-forming ability and excellent soft magnetic properties. • Proper Cu substitution improves magnetic properties without obvious deterioration of glass-forming ability

  9. Performance studies under high irradiation and ageing properties of resistive bulk Micromegas chambers at the new CERN Gamma Irradiation Facility

    Sidiropoulou, O.; Gonzalez, B. Alvarez; Bianco, M.; Farina, E.M.; Iengo, P.; Longo, L.; Pfeiffer, D.; Wotschack, J.

    2017-01-01

    Resistive bulk Micromegas chambers, produced at CERN, have been installed at the new CERN Gamma Irradiation Facility (GIF++) in order to study the effects of ageing and to evaluate the detector behaviour under high irradiation. The chambers have an active area of 10×10 cm 2 , strip pitch of 400 μm and an amplification gap of 128 μm. We present the detector performance as a function of the background rate of up to 20 MHz/cm 2 . - Highlights: • Small-size resistive bulk Micromegas detectors have been exposed to the new GIF++. • 9 months irradiation to γ up to 20 Mhz/cm 2 . 0.09 C/cm 2 collected integrated charge. • Νo degradation of the detector performance was observed. • Muon tracks successfully reconstructed up to 68 kHz/cm 2 gamma background. • Higher background rates will be studied in the coming months.

  10. Hydrogen permeation modification of 4140 steel by ion nitriding with pulsed plasmas

    Bruzzoni, P.; Ortiz, M. [Comision Nacional de Energia Atomica, Buenos Aires (Argentina); Bruehl, S.P.; Gomez, B.J.A.; Feugeas, J.N. [Inst. de Fisica Rosario (UNR-CONICET), Rosario (Argentina); Nosei, L. [Inst. de Mecanica Aplicada y Estructuras (UNR), Rosario (Argentina)

    1998-11-10

    It is widely known that the hydrogen in steel produces embrittlement. This effect may cause the failure of the elements (confining walls, mechanical parts, etc.) whose surfaces are in contact with this gas or with processes in which hydrogen is continuously generated. In this work it is shown that the ion nitriding of the surface of AISI 4140 is a good mechanism to act as a barrier against hydrogen permeation in its bulk. The ion nitriding was performed using a square wave DC glow discharge. The development of a compound layer of iron nitrides was observed as the cause of the hydrogen permeation reduction. For equal duration of treatment, thicker compound layers were developed in higher discharge/post-discharge ratios in the square wave of the applied voltage onto the sample (cathode), with a greater reduction of hydrogen permeation coefficient as a consequence. Nevertheless, the permeation was not reduced to zero in any of the treatment conditions used. The results of the analysis of the permeation tests and the image of the photomicrographs showed that the existence of cracks, fractures, failures, etc. in the compound layer (pre-existing in the AISI 4140 steel) could be the cause of the residual hydrogen permeation. This can be attributed to the movement of the hydrogen through these defects diffusing through the original {alpha}-Fe phase of the non-treated steel. (orig.) 11 refs.

  11. Novel low temperature processing techniques for apatite ceramics and chitosan polymer composite bulk materials and its mechanical properties

    Onoki, Takamasa; Nakahira, Atsushi; Tago, Tomoyuki; Hasegawa, Yoshiyuki; Kuno, Tomoaki

    2012-12-01

    A co-precipitation method was used for processing chitosan (CHI)/calcium hydrogen phosphate dehydrate (DCPD) hybrid material. CHI solution was mixed into 1.0-M calcium nitrate solution. CHI/DCPD hybrid material was prepared by the above explained addition of CHI and Ca ion source to 1.0-M diammonium hydrogen phosphate solution. It was observed by transmission electron microscopy that CHI and DCPD were mixed within submicron meter scale. CHI/HA bulk materials derived from the CHI/DCPD hybrid materials were obtained by using a hydrothermal hot-pressing (HHP) method. A pressure of 40 MPa was initially applied to the sample. An HHP autoclave was heated up to 150 °C for 2 h. Modified 3-point bending tests were conducted to obtain an easy estimate of the fracture toughness for the CHI/HA bulk materials made with the HHP method. The critical stress intensity factor Kc of the fabricated CHI/HA bulk materials was enhanced from 0.30 to 0.40 MPam1/2 by the hybridization of CHI into DCPD.

  12. Implanted-tritium permeation experiments

    Longhurst, G.R.; Holland, D.F.; Casper, L.A.; Hsu, P.Y.; Miller, L.G.; Schmunk, R.E.; Watts, K.D.; Wilson, C.J.; Kershner, C.J.; Rogers, M.L.

    1982-04-01

    In fusion reactors, charge exchange neutral atoms of tritium coming from the plasma will be implanted into the first wall and other interior structures. EG and G Idaho is conducting two experiments to determine the magnitude of permeation into the coolant streams and the retention of tritium in those structures. One experiment uses an ion gun to implant deuterium. The ion gun will permit measurements to be made for a variety of implantation energies and fluxes. The second experiment utilizes a fission reactor to generate a tritium implantation flux by the 3 He(n,p) 3 H reaction. This experiment will simulate the fusion reactor radiation environment. We also plan to verify a supporting analytical code development program, in progress, by these experiments

  13. Permeation Tests on Polypropylene Fiber Materials

    2018-03-16

    Permeation Tests on Polypropylene Fiber Materials Brandy J. White Martin H. Moore Brian J. Melde Laboratory for the Study of Molecular Interfacial...ABSTRACT Permeation Tests on Polypropylene Fiber Materials Brandy J. White, Martin H. Moore, Brian J. Melde Center for Bio/Molecular Science

  14. Tritium permeation in stainless-steel structures exposed to plasma ions

    Anderl, R.A.; Holland, D.F.; Struttmann, D.A.; Longhurst, G.R.; Merrill, B.J.

    1985-01-01

    This paper presents a comparison of the hydrogen permeation properties of the austenitic primary candidate alloy, PCA, and of the advanced ferritic alloy, HT-9. The comparison is based on experimental measurements of the permeation and reemission of deuterium from specimens undergoing implantation with 3-keV, D 3 + ions produced by an accelerator. Characterization of the specimen surface facing the ion beam is provided by secondary ion mass spectrometer (SIMS) analysis of the species sputtered from the surface during the implantation. Recombination and diffusivity data for PCA and HT-9 were derived from an analysis in which model calculations were applied to the reemission and permeation measurements

  15. Epitaxially Grown Layered MFI–Bulk MFI Hybrid Zeolitic Materials

    Kim, Wun-gwi

    2012-11-27

    The synthesis of hybrid zeolitic materials with complex micropore-mesopore structures and morphologies is an expanding area of recent interest for a number of applications. Here we report a new type of hybrid zeolite material, composed of a layered zeolite material grown epitaxially on the surface of a bulk zeolite material. Specifically, layered (2-D) MFI sheets were grown on the surface of bulk MFI crystals of different sizes (300 nm and 10 μm), thereby resulting in a hybrid material containing a unique morphology of interconnected micropores (∼0.55 nm) and mesopores (∼3 nm). The structure and morphology of this material, referred to as a "bulk MFI-layered MFI" (BMLM) material, was elucidated by a combination of XRD, TEM, HRTEM, SEM, TGA, and N2 physisorption techniques. It is conclusively shown that epitaxial growth of the 2-D layered MFI sheets occurs in at least two principal crystallographic directions of the bulk MFI crystal and possibly in the third direction as well. The BMLM material combines the properties of bulk MFI (micropore network and mechanical support) and 2-D layered MFI (large surface roughness, external surface area, and mesoporosity). As an example of the uses of the BMLM material, it was incorporated into a polyimide and fabricated into a composite membrane with enhanced permeability for CO2 and good CO2/CH4 selectivity for gas separations. SEM-EDX imaging and composition analysis showed that the polyimide and the BMLM interpenetrate into each other, thereby forming a well-adhered polymer/particle microstructure, in contrast with the defective interfacial microstructure obtained using bare MFI particles. Analysis of the gas permeation data with the modified Maxwell model also allows the estimation of the effective volume of the BMLM particles, as well as the CO2 and CH4 gas permeabilities of the interpenetrated layer at the BMLM/polyimide interface. © 2012 American Chemical Society.

  16. An efficient and economical way to enhance the performance of present HTS Maglev systems by utilizing the anisotropy property of bulk superconductors

    Deng Zigang; Wang Jiasu; Zheng Jun; Zhang Ya; Wang Suyu

    2013-01-01

    We report a simple, efficient and economical way to enhance the levitation or guidance performance of present high-temperature superconducting (HTS) Maglev systems by exploring the anisotropic properties of the critical current density in the a–b plane and along the c-axis of bulk superconductors. In the method, the bulk laying mode with different c-axis directions is designed to match with the magnetic field configuration of the applied permanent magnet guideway (PMG). Experimental results indicate that more than a factor of two improvement in the levitation force or guidance force is achieved when changing the laying mode of bulk superconductors from the traditional fashion of keeping the c-axis vertical to the PMG surface to the studied one of keeping the c-axis parallel to the PMG surface, at the maximum horizontal and vertical magnetic field positions of the PMG, respectively. These phenomena resulted from the physical nature of the generated levitation force and guidance force (electromagnetic forces) and the fact that there are different critical current densities in the a–b plane and along the c axis. Based on the experimental results, new HTS Maglev systems can be designed to meet the requirements of practical heavy-load or curved-route applications. (paper)

  17. An efficient and economical way to enhance the performance of present HTS Maglev systems by utilizing the anisotropy property of bulk superconductors

    Deng, Zigang; Wang, Jiasu; Zheng, Jun; Zhang, Ya; Wang, Suyu

    2013-02-01

    We report a simple, efficient and economical way to enhance the levitation or guidance performance of present high-temperature superconducting (HTS) Maglev systems by exploring the anisotropic properties of the critical current density in the a-b plane and along the c-axis of bulk superconductors. In the method, the bulk laying mode with different c-axis directions is designed to match with the magnetic field configuration of the applied permanent magnet guideway (PMG). Experimental results indicate that more than a factor of two improvement in the levitation force or guidance force is achieved when changing the laying mode of bulk superconductors from the traditional fashion of keeping the c-axis vertical to the PMG surface to the studied one of keeping the c-axis parallel to the PMG surface, at the maximum horizontal and vertical magnetic field positions of the PMG, respectively. These phenomena resulted from the physical nature of the generated levitation force and guidance force (electromagnetic forces) and the fact that there are different critical current densities in the a-b plane and along the c axis. Based on the experimental results, new HTS Maglev systems can be designed to meet the requirements of practical heavy-load or curved-route applications.

  18. Ferromagnetic bulk glassy alloys

    Inoue, Akihisa; Makino, Akihiro; Mizushima, Takao

    2000-01-01

    This paper deals with the review on the formation, thermal stability and magnetic properties of the Fe-based bulk glassy alloys in as-cast bulk and melt-spun ribbon forms. A large supercooled liquid region over 50 K before crystallization was obtained in Fe-(Al, Ga)-(P, C, B, Si), Fe-(Cr, Mo, Nb)-(Al, Ga)-(P, C, B) and (Fe, Co, Ni)-Zr-M-B (M=Ti, Hf, V, Nb, Ta, Cr, Mo and W) systems and bulk glassy alloys were produced in a thickness range below 2 mm for the Fe-(Al, Ga)-(P, C, B, Si) system and 6 mm for the Fe-Co-(Zr, Nb, Ta)-(Mo, W)-B system by copper-mold casting. The ring-shaped glassy Fe-(Al, Ga)-(P, C, B, Si) alloys exhibit much better soft magnetic properties as compared with the ring-shaped alloy made from the melt-spun ribbon because of the formation of the unique domain structure. The good combination of high glass-forming ability and good soft magnetic properties indicates the possibility of future development as a new bulk glassy magnetic material

  19. Permeation of hydrogen through metal membranes

    Wienhold, P.; Rota, E.; Waelbroeck, F.; Winter, J.; Banno, Tatsuya.

    1986-08-01

    Experiments show that the permeant flux of hydrogen through a metal membrane at low driving pressures ( r is introduced into the model as a new material constant and the rate equations are given. After the description of the wall pump effect, a variety of different limiting cases are discussed for a symmetrical permeation membrane. This is modified to the asymmetric case and to the influence of particle implantation. The permeation number W turns out to be a dimensionless quantity which characterizes the permeation range and predicts the permeant flux in steady state. (orig.)

  20. Studies on Tasar Cocoon Cooking Using Permeation Method

    Javali, Uday C.; Malali, Kiran B.; Ramya, H. G.; Naik, Subhas V.; Padaki, Naveen V.

    2018-02-01

    Cocoon cooking is an important process before reeling of tasar silk yarn. Cooking ensures loosening of the filaments in the tasar cocoons thereby easing the process of yarn withdrawal during reeling process. Tasar cocoons have very hard shell and hence these cocoons need chemical cooking process to loosen the silk filaments. Attempt has been made in this article to study the effect of using vacuum permeation chamber for tasar cocoon cooking in order to reduce the cooking time and improve the quality of tasar silk yarn. Vacuum assisted permeation cooking method has been studied in this article on tasar daba cocoons for cooking efficiency, deflossing and reelability. Its efficiency has been evaluated with respect to different cooking methods viz, traditional and open pan cooking methods. The tasar silk produced after reeling process has been tested for fineness, strength and cohesion properties. Results indicate that permeation method of tasar cooking ensures uniform cooking with higher efficiency along with better reeling performance and improved yarn properties.

  1. Experimental measurements of the permeation of hydrogen isotopes in lithium filled niobium cells

    Goodall, D.H.J.; McCracken, G.M.; Austin, G.E.

    1976-01-01

    Lithium filled niobium cells have been heated in vacua at temperatures in the range 300 to 900 0 C. By measuring the flow of deuterium into the cell it has been possible to make estimates of the rate of permeation of deuterium in the niobium wall. After initial fast diffusion into the capsule the rate of permeation becomes very much slower than that determined by diffusion in the bulk niobium indicating that a second, slower, rate process is involved. Measurements of the rate of deuterium permeation out of the cell have been made for a number of different cell geometries and a range of temperatures. The results indicate that the slow rate process, which is dominant at low concentrations, is the desorption step from the metal to the gas phase

  2. An approach to the research on ion and water properties in the interphase between the plasma membrane and bulk extracellular solution.

    Hibino, Hiroshi; Takai, Madoka; Noguchi, Hidenori; Sawamura, Seishiro; Takahashi, Yasufumi; Sakai, Hideki; Shiku, Hitoshi

    2017-07-01

    In vivo, cells are immersed in an extracellular solution that contains a variety of bioactive substances including ions and water. Classical electrophysiological analyses of epithelial cells in the stomach and small intestine have revealed that within a distance of several hundred micrometers above their apical plasma membrane, lies an extracellular layer that shows ion concentration gradients undetectable in the bulk phase. This "unstirred layer", which contains stagnant solutes, may also exist between the bulk extracellular solution and membranes of other cells in an organism and may show different properties. On the other hand, an earlier study using a bacterial planar membrane indicated that H + released from a transporter migrates in the horizontal direction along the membrane surface much faster than it diffuses vertically toward the extracellular space. This result implies that between the membrane surface and unstirred layer, there is a "nanointerface" that has unique ionic dynamics. Advanced technologies have revealed that the nanointerface on artificial membranes possibly harbors a highly ordered assembly of water molecules. In general, hydrogen bonds are involved in formation of the ordered water structure and can mediate rapid transfer of H + between neighboring molecules. This description may match the phenomenon on the bacterial membrane. A recent study has suggested that water molecules in the nanointerface regulate the gating of K + channels. Here, the region comprising the unstirred layer and nanointerface is defined as the interphase between the plasma membrane and bulk extracellular solution (iMES). This article briefly describes the physicochemical properties of ions and water in the iMES and their physiological significance. We also describe the methodologies that are currently used or will be applicable to the interphase research.

  3. Formation, thermal stability and mechanical properties of bulk glassy alloys with a diameter of 20 mm in Zr-(Ti,Nb)-Al-Ni-Cu system

    Inoue, A.; Zhang, Q.S.; Zhang, W.; Yubuta, K.; Son, K.S.; Wang, X.M.

    2009-01-01

    Bulk glassy alloy rods with a diameter of 20 mm were produced for Zr 61 Ti 2 Nb 2 Al 7.5 Ni 10 Cu 17.5 and Zr 60 Ti 2 Nb 2 Al 7.5 Ni 10 Cu 18.5 by a tilt casting method. The replacement of Zr by a small amount of Ti and Nb caused a distinct increase in the maximum diameter from 16 mm for Zr 65 Al 7.5 Ni 10 Cu 17.5 to 20 mm, accompanying the decrease in liquidus temperature and the increase in reduced glass transition temperature. The primary precipitation phase from supercooled liquid also shows a distinct change, i.e., from coexistent Zr 2 Cu, Zr 2 Ni and Zr 6 NiAl 2 phases for the 65%Zr alloy to an icosahedral phase for the 61%Zr and 60%Zr alloys. These results allow us to presume that the enhancement of the glass-forming ability is due to an increase in the stability of supercooled liquid against crystallization caused by the development of icosahedral short-range ordered atomic configurations. The 60%Zr specimens taken from the central and near-surface regions in the transverse cross section at the site which is 15 mm away from the bottom surface of the cast glassy rod with a diameter of 20 mm exhibit good mechanical properties under a compressive deformation mode, i.e., Young's modulus of 81 GPa, large elastic strain of 0.02, high yield strength of 1610 MPa and distinct plastic strain of 0.012. Besides, a number of shear bands are observed along the maximum shear stress plane on the peripheral surface near the final fracture site. The finding of producing the large scale Zr-based bulk glassy alloys exhibiting reliable mechanical properties is encouraging for future advancement of bulk glassy alloys as a new type of functional material. (author)

  4. Water absorption in thermally grown oxides on SiC and Si: Bulk oxide and interface properties

    Liu, Gang [Institute for Advanced Materials, Devices and Nanotechnology, Rutgers University, Piscataway, New Jersey 08854 (United States); Xu, Can; Feldman, Leonard C. [Institute for Advanced Materials, Devices and Nanotechnology, Rutgers University, Piscataway, New Jersey 08854 (United States); Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854 (United States); Yakshinskiy, Boris; Wielunski, Leszek; Gustafsson, Torgny [Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854 (United States); Bloch, Joseph [Institute for Advanced Materials, Devices and Nanotechnology, Rutgers University, Piscataway, New Jersey 08854 (United States); NRCN, Beer-Sheva 84190 (Israel); Dhar, Sarit [Department of Physics, Auburn University, Auburn, Alabama 36849 (United States)

    2014-11-10

    We combine nuclear reaction analysis and electrical measurements to study the effect of water exposure (D{sub 2}O) on the n-type 4H-SiC carbon face (0001{sup ¯}) MOS system and to compare to standard silicon based structures. We find that: (1) The bulk of the oxides on Si and SiC behave essentially the same with respect to deuterium accumulation; (2) there is a significant difference in accumulation of deuterium at the semiconductor/dielectric interface, the SiC C-face structure absorbs an order of magnitude more D than pure Si; (3) standard interface passivation schemes such as NO annealing greatly reduce the interfacial D accumulation; and (4) the effective interfacial charge after D{sub 2}O exposure is proportional to the total D amount at the interface.

  5. Combined effect of bulk and surface damage on strip insulation properties of proton irradiated n$^{+}$-p silicon strip sensors

    Dalal, R; Ranjan, K; Moll, M; Elliott-Peisert, A

    2014-01-01

    Silicon sensors in next generation hadron colliders willface a tremendously harsh radiation environment. Requirement tostudy rarest reaction channels with statistical constraints hasresulted in a huge increment in radiation flux, resulting in bothsurface damage and bulk damage. For sensors which are used in acharged hadron environment, both of these degrading processes takeplace simultaneously. Recently it has been observed in protonirradiated n$^{+}$-p Si strip sensors that n$^{+}$ strips had a goodinter-strip insulation with low values of p-spray and p-stop dopingdensities which is contrary to the expected behaviour from thecurrent understanding of radiation damage. In this work a simulationmodel has been devised incorporating radiation damage to understandand provide a possible explanation to the observed behaviour ofirradiated sensors.

  6. Electrochemical properties of the passive film on bulk Zr–Fe–Cr intermetallic fabricated by spark plasma sintering

    Bai, Yakui [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Ling, Yunhan, E-mail: yhling@mail.tsinghua.edu.cn [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Lai, Wensheng [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Xing, Shupei; Ma, Wen [School of Materials Science and Engineering, Inner Mongolia University of Technology, Huhhot 010051 (China)

    2016-12-01

    Highlights: • SPS was employed to prepare Zr-based intermetallics which were commonly existed in zircaloy. • Zr-based intermetallics act as cathode when they embedded in zirconium matrix. • The passive films on surface of intermetallics behaved as n-type semiconductors. • Carrier concentration of Zr(Fe{sub 3}Cr){sub 2} was much lower than that of other intermetallics. - Abstract: Although Zr-based second phase particles (SPPs) are important factors influencing corrosion resistance of zircaloy cladding materials, the corrosion behavior of SPPs has not been investigated by means of electrochemical method so far. In order to clarify the role of SPPs commonly existed in zircaloy, bulk Zr-based intermetallics were firstly fabricated by spark plasma sintering (SPS) at temperatures 1373 K and an applied pressure of 60 MPa in this work. Both the natural passive film on surface and oxidation behavior of intermetallic has been investigated in this work. X-ray diffraction (XRD) pattern showed that as-prepared intermetallic of crystal structure belongs to Laves phase with AB{sub 2} type. Electrochemical measurement of passive film on surface of bulk Zr-based intermetallic exhibited significant difference with that of zirconium. Potentiodynamic measurements results revealed that intermetallic exhibited higher corrosion potential and lower corrosion current density than that of pure zirconium, implying that Zr-based second phase will act as cathode when they are included in zirconium matrix. Meanwhile, significant improvement of Zr–Fe–Cr intermetallic on the water chemistry corrosion resistance was demonstrated comparing with Zr–Fe and Zr–Cr binary intermetallics.

  7. Monoterpene oxidation in an oxidative flow reactor: SOA yields and the relationship between bulk gas-phase properties and organic aerosol growth

    Friedman, B.; Link, M.; Farmer, D.

    2016-12-01

    We use an oxidative flow reactor (OFR) to determine the secondary organic aerosol (SOA) yields of five monoterpenes (alpha-pinene, beta-pinene, limonene, sabinene, and terpinolene) at a range of OH exposures. These OH exposures correspond to aging timescales of a few hours to seven days. We further determine how SOA yields of beta-pinene and alpha-pinene vary as a function of seed particle type (organic vs. inorganic) and seed particle mass concentration. We hypothesize that the monoterpene structure largely accounts for the observed variance in SOA yields for the different monoterpenes. We also use high-resolution time-of-flight chemical ionization mass spectrometry to calculate the bulk gas-phase properties (O:C and H:C) of the monoterpene oxidation systems as a function of oxidant concentrations. Bulk gas-phase properties can be compared to the SOA yields to assess the capability of the precursor gas-phase species to inform the SOA yields of each monoterpene oxidation system. We find that the extent of oxygenated precursor gas-phase species corresponds to SOA yield.

  8. Thermal conductivity, bulk properties, and thermal stratigraphy of silicic tuffs from the upper portion of hole USW-G1, Yucca Mountain, Nye County, Nevada

    Lappin, A.R.; VanBuskirk, R.G.; Enniss, D.O.; Buters, S.W.; Prater, F.M.; Muller, C.B.; Bergosh, J.L.

    1982-03-01

    Thermal-conductivity and bulk-property measurements were made on welded and nonwelded silicic tuffs from the upper portion of Hole USW-G1, located near the southwestern margin of the Nevada Test Site. Bulk-property measurements were made by standard techniques. Thermal conductivities were measured at temperatures as high as 280 0 C, confining pressures to 10 MPa, and pore pressures to 1.5 MPa. Extrapolation of measured saturated conductivities to zero porosity suggests that matrix conductivity of both zeolitized and devitrified tuffs is independent of stratigraphic position, depth, and probably location. This fact allows development of a thermal-conductivity stratigraphy for the upper portion of Hole G1. Estimates of saturated conductivities of zeolitized nonwelded tuffs and devitrified tuffs below the water table appear most reliable. Estimated conductivities of saturated densely welded devitrified tuffs above the water table are less reliable, due to both internal complexity and limited data presently available. Estimation of conductivity of dewatered tuffs requires use of different air thermal conductivities in devitrified and zeolitized samples. Estimated effects of in-situ fracturing generally appear negligible

  9. SC lipid model membranes designed for studying impact of ceramide species on drug diffusion and permeation--part II: diffusion and permeation of model drugs.

    Ochalek, M; Podhaisky, H; Ruettinger, H-H; Wohlrab, J; Neubert, R H H

    2012-10-01

    The barrier function of two quaternary stratum corneum (SC) lipid model membranes, which were previously characterized with regard to the lipid organization, was investigated based on diffusion studies of model drugs with varying lipophilicities. Diffusion experiments of a hydrophilic drug, urea, and more lipophilic drugs than urea (i.e. caffeine, diclofenac sodium) were conducted using Franz-type diffusion cells. The amount of permeated drug was analyzed using either HPLC or CE technique. The subjects of interest in the present study were the investigation of the influence of physicochemical properties of model drugs on their diffusion and permeation through SC lipid model membranes, as well as the study of the impact of the constituents of these artificial systems (particularly ceramide species) on their barrier properties. The diffusion through both SC lipid model membranes and the human SC of the most hydrophilic model drug, urea, was faster than the permeation of the more lipophilic drugs. The slowest rate of permeation through SC lipid systems occurred in the case of caffeine. The composition of SC lipid model membranes has a significant impact on their barrier function. Model drugs diffused and permeated faster through Membrane II (presence of Cer [EOS]). In terms of the barrier properties, Membrane II is much more similar to the human SC than Membrane I. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Effect of Yttrium Addition on Glass-Forming Ability and Magnetic Properties of Fe–Co–B–Si–Nb Bulk Metallic Glass

    Teruo Bitoh

    2015-06-01

    Full Text Available The glass-forming ability (GFA and the magnetic properties of the [(Fe0.5Co0.50.75B0.20Si0.05]96Nb4−xYx bulk metallic glasses (BMGs have been studied. The partial replacement of Nb by Y improves the thermal stability of the glass against crystallization. The saturation mass magnetization (σs exhibits a maximum around 2 at. % Y, and the value of σs of the alloy with 2 at. % Y is 6.5% larger than that of the Y-free alloy. The coercivity shows a tendency to decrease with increasing Y content. These results indicate that the partial replacement of Nb by Y in the Fe–Co–B–Si–Nb BMGs is useful to simultaneous achievement of high GFA, high σs, and good soft magnetic properties.

  11. Theoretical approach to embed nanocrystallites into a bulk crystalline matrix and the embedding influence on the electronic band structure and optical properties of the resulting heterostructures.

    Balagan, Semyon Anatolyevich; Nazarov, Vladimir U; Shevlyagin, Alexander Vladimirovich; Goroshko, Dmitrii L; Galkin, N G

    2018-05-03

    We develop an approach and present results of the combined molecular dynamics and density functional theory calculations of the structural and optical properties of the nanometer-sized crystallites embedded in a bulk crystalline matrix. The method is designed and implemented for both compatible and incompatible lattices of the nanocrystallite (NC) and the host matrix, when determining the NC optimal orientation relative to the matrix constitutes a challenging problem. We suggest and substantiate an expression for the cost function of the search algorithm, which is the energy per supercell generalized for varying number of atoms in the latter. The epitaxial relationships at the Si/NC interfaces and the optical properties are obtained and found to be in a reasonable agreement with experimental data. Dielectric functions show significant sensitivity to the NC's orientation relative to the matrix at energies below 0.5 eV. © 2018 IOP Publishing Ltd.

  12. Influence of thermal annealing-induced molecular aggregation on film properties and photovoltaic performance of bulk heterojunction solar cells based on a squaraine dye

    Zhang, Pengpeng; Ling, Zhitian; Chen, Guo; Wei, Bin

    2018-04-01

    Squaraine (SQ) dyes have been considered as efficient photoactive materials for organic solar cells. In this work, we purposely controlled the molecular aggregation of an SQ dye, 2,4-bis[4-(N,N-dibutylamino)-2-dihydroxyphenyl] SQ (DBSQ-(OH)2) in the DBSQ(OH)2:[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) blend film by using the thermal annealing method, to study the influence of the molecular aggregation on film properties as well as the photovoltaic performance of DBSQ(OH)2:PCBM-based bulk heterojunction (BHJ) solar cells. Our results demonstrate that thermal annealing may change the aggregation behavior of DBSQ(OH)2 in the DBSQ(OH)2:PCBM film, and thus significantly influence the surface morphology, optical and electrical properties of the blend film, as well as the photovoltaic performance of DBSQ(OH)2:PCBM BHJ cells.

  13. Theoretical approach to embed nanocrystallites into a bulk crystalline matrix and the embedding influence on the electronic band structure and optical properties of the resulting heterostructures

    Balagan, Semyon A.; Nazarov, Vladimir U.; Shevlyagin, Alexander V.; Goroshko, Dmitrii L.; Galkin, Nikolay G.

    2018-06-01

    We develop an approach and present results of the combined molecular dynamics and density functional theory calculations of the structural and optical properties of the nanometer-sized crystallites embedded in a bulk crystalline matrix. The method is designed and implemented for both compatible and incompatible lattices of the nanocrystallite (NC) and the host matrix, when determining the NC optimal orientation relative to the matrix constitutes a challenging problem. We suggest and substantiate an expression for the cost function of the search algorithm, which is the energy per supercell generalized for varying number of atoms in the latter. The epitaxial relationships at the Si/NC interfaces and the optical properties are obtained and found to be in a reasonable agreement with experimental data. Dielectric functions show significant sensitivity to the NC’s orientation relative to the matrix at energies below 0.5 eV.

  14. Permeation of deuterium implanted into vanadium alloys

    Anderl, R.A.; Longhurst, G.R.; Struttmann, D.A.

    1986-05-01

    Permeation of deuterium through the vanadium alloy, V-15Cr-5Ti, was investigated using 3-keV, D 3 + ion beams from a small accelerator. The experiments consisted of measurements of the deuterium reemission and permeation rates as a function of implantation fluence for 0.5-mm thick specimens heated to tempertures from 623 to 823 0 K. Implantation-side surface characterization was made by simultaneous measurements of sputtered ions with a secondary ion mass spectrometer (SIMS). Analyses of these measurements indicate that for the experimental conditions used, the steady-state deuterium permeation flux in V-15Cr-5Ti is approximately 18% of the implantation flux. This corresponds to approximately 1000 times that seen in the ferritic steel, HT-9, under comparable conditions. Measurement of deuterium diffusivity in V-15Cr-5Ti using permeation break-through times indicates D = 1.4 x 10 -8 exp(-.11 eV/kT) (m 2 /s)

  15. Dissolution and permeation characteristics of artemether tablets ...

    characterized by delayed drug release but enhanced permeation of the released drug. Keywords: ... and prosopis gum as binders and to consider the relationship between ..... higher tensile strength and higher brittle fracture index compared ...

  16. Bulk-Like Electrical Properties Induced by Contact-Limited Charge Transport in Organic Diodes: Revised Space Charge Limited Current

    Xu, Guangwei; Gao, Nan; Lu, Congyan; Wang, Wei; Ji, Zhuoyu; Bi, Chong; Han, Zhiheng; Lu, Nianduan; Yang, Guanhua; Li, Yuan; Liu, Qi; Li, Ling; Liu, Ming

    2018-01-01

    , the charge transport properties of organic diodes are usually characterized by probing the current–voltage (I–V) curves of the devices. However, to unveil the landscape of the underlying potential/charge distribution, which essentially determines the I

  17. Proton permeation of lipid bilayers.

    Deamer, D W

    1987-10-01

    Proton permeation of the lipid bilayer barrier has two unique features. First, permeability coefficients measured at neutral pH ranges are six to seven orders of magnitude greater than expected from knowledge of other monovalent cations. Second, proton conductance across planar lipid bilayers varies at most by a factor of 10 when pH is varied from near 1 to near 11. Two mechanisms have been proposed to account for this anomalous behavior: proton conductance related to contaminants of lipid bilayers, and proton translocation along transient hydrogen-bonded chains (tHBC) of associated water molecules in the membrane. The weight of evidence suggests that trace contaminants may contribute to proton conductance across planar lipid membranes at certain pH ranges, but cannot account for the anomalous proton flux in liposome systems. Two new results will be reported here which were designed to test the tHBC model. These include measurements of relative proton/potassium permeability in the gramicidin channel, and plots of proton flux against the magnitude of pH gradients. (1) The relative permeabilities of protons and potassium through the gramicidin channel, which contains a single strand of hydrogen-bonded water molecules, were found to differ by at least four orders of magnitude when measured at neutral pH ranges. This result demonstrates that a hydrogen-bonded chain of water molecules can provide substantial discrimination between protons and other cations. It was also possible to calculate that if approximately 7% of bilayer water was present in a transient configuration similar to that of the gramicidin channel, it could account for the measured proton flux. (2) The plot of proton conductance against pH gradient across liposome membranes was superlinear, a result that is consistent with one of three alternative tHBC models for proton conductance described by Nagle elsewhere in this volume.

  18. Analysis of transient permeation behavior of hydrogen isotope caused by abrupt temperature change of first wall and blanket wall material

    Yamawaki, Michio; Tanaka, Satoru; Kiyoshi, Tsukasa

    1989-01-01

    To obtain further information on the transient permeation behavior of hydrogen isotopes as caused by an abrupt temperature change, numerical calculations were carried out for two typical metals, nickel and vanadium. Deuterium permeation through nickel is analyzed as a typical case of bulk-diffusion-limited permeation. Its transient behavior changed dramatically according to the specimen thickness. The transient behavior, in general, is separated into two parts, initial and latter period behaviors. Conditions which cause such a separation were evaluated. Evaluation of the hydrogen diffusivity and solubility by an analysis of transient curves of hydrogen permeation was carried out. The transient behavior of simultaneous gas- and ion-driven hydrogen permeation through vanadium was also analyzed. Overshooting of the hydrogen permeation rate appears with an abrupt temperature increase. Increasing the impinging ion flux causes the overshooting peak to become sharper, and also reduces the change of the steady-state permeation rate to be attained after the temperature change compared with the initial value. (orig.)

  19. Study of microstructure and correlative magnetic property in bulk Fe{sub 61}Nd{sub 10}B{sub 25}Nb{sub 4} permanent magnet

    Man, H.; Xu, H. [Laboratory for Microstructures, Shanghai University, Shanghai 200444 (China); Liu, H.W. [The Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia); Tan, X.H., E-mail: tanxiaohua123@163.com [Laboratory for Microstructures, Shanghai University, Shanghai 200444 (China); Peng, J.C.; Bai, Q. [Laboratory for Microstructures, Shanghai University, Shanghai 200444 (China)

    2012-11-01

    Highlights: Black-Right-Pointing-Pointer A fully dense bulk Fe{sub 61}Nd{sub 10}B{sub 25}Nb{sub 4} permanent magnet was obtained by the simple process of copper mold casting and subsequent annealed at 943 K. Black-Right-Pointing-Pointer The relationship between microstructures and correlative magnetic property of Fe{sub 61}Nd{sub 10}B{sub 25}Nb{sub 4} alloy was investigated. Black-Right-Pointing-Pointer The high value of intrinsic coercivity of 1191 kA/m was obtained due to the existence of hard magnetic Nd{sub 2}Fe{sub 14}B phase. - Abstract: The correlation between microstructure and magnetic property of a bulk Fe{sub 61}Nd{sub 10}B{sub 25}Nb{sub 4} alloy are investigated. The microstructure of the as-cast Fe{sub 61}Nd{sub 10}B{sub 25}Nb{sub 4} alloy shows a small amount of NbFeB phase with a grain size of 500 nm embedded in an amorphous matrix. The as-cast sample shows soft magnetic behavior at room temperature, after a heat treatment the hard magnetic properties are observed. A fully dense bulk Fe{sub 61}Nd{sub 10}B{sub 25}Nb{sub 4} permanent magnet is obtained with an intrinsic coercivity ({sub i}H{sub c}) of 1191 kA/m and a maximum energy product ((BH){sub max}) of 31.7 kJ/m{sup 3} after annealing at 943 K for 20 min. The corresponding microstructure consists of Nd{sub 2}Fe{sub 14}B, NdFe{sub 4}B{sub 4} and NbFeB phases. The existence of the hard magnetic Nd{sub 2}Fe{sub 14}B phase is the reason resulting in a high value of {sub i}H{sub c}. On the other hand, the influences of NdFe{sub 4}B{sub 4} and NbFeB phases in the annealed specimen on the magnetic properties are also discussed.

  20. Permeation of Ionic Liquids through the skin

    Ana Júlio

    2017-12-01

    Full Text Available Alternative forms of drug delivery such as delivery through the skin, have been developed to explore other routes. However, the incorporation of poorly soluble or partially insoluble drugs into these delivery systems represents a major problem. Ionic liquids (ILs may be incorporated in aqueous, oily or hydroalcoholic solutions and thus, may be used as excipients in drug delivery systems to increase/improve the topical and transdermal drug delivery. However, it is fundamental to consider the cytotoxicity of these salts and it is also crucial to evaluate if these compounds permeate through the skin. Herein, three imidazole-based ILs: [C2mim][Br], [C4mim][Br] and [C6mim][Br], were synthesized and each IL was incorporated within caffeine saturated solutions. Permeation studies of the active (caffeine in these solutions were performed to evaluate the amount of IL that permeated through the porcine ear skin in the presence of the active. To achieve this, gravimetric studies of the receptor compartment were performed. Results showed that the more lipophilic IL [C6mim][Br] presented the highest permeation through the skin. The permeation is dependent upon the size of the alkyl chain of the IL, and as more than 60% of the ILs permeate is it vital to consider the cytotoxicity of these salts when considering their incorporation in topical systems.

  1. Water vapor permeation and dehumidification performance of poly(vinyl alcohol)/lithium chloride composite membranes

    Bui, Duc Thuan

    2015-10-09

    Thin and robust composite membranes comprising stainless steel scaffold, fine and porous TiO2 and polyvinyl alcohol/lithium chloride were fabricated and studied for air dehumidification application. Higher hydrophilicity, sorption and permeation were observed for membranes with increased lithium chloride content up to 50%. The permeation and sorption properties of the membranes were investigated under different temperatures. The results provided a deeper insight into the membrane water vapor permeation process. It was specifically noted that lithium chloride significantly reduces water diffusion energy barrier, resulting in the change of permeation energy from positive to negative values. Higher water vapor permeance was observed for the membrane with higher LiCl content at lower temperature. The isothermal air dehumidification tests show that the membrane is suitable for dehumidifying air in high humid condition. Additionally, results also indicate a trade-off between the humidity ratio drop with the water vapor removal rate when varying air flowrate.

  2. Optical properties of C-doped bulk GaN wafers grown by halide vapor phase epitaxy

    Khromov, S.; Hemmingsson, C.; Monemar, B.; Hultman, L.; Pozina, G.

    2014-01-01

    Freestanding bulk C-doped GaN wafers grown by halide vapor phase epitaxy are studied by optical spectroscopy and electron microscopy. Significant changes of the near band gap (NBG) emission as well as an enhancement of yellow luminescence have been found with increasing C doping from 5 × 10 16 cm −3 to 6 × 10 17 cm −3 . Cathodoluminescence mapping reveals hexagonal domain structures (pits) with high oxygen concentrations formed during the growth. NBG emission within the pits even at high C concentration is dominated by a rather broad line at ∼3.47 eV typical for n-type GaN. In the area without pits, quenching of the donor bound exciton (DBE) spectrum at moderate C doping levels of 1–2 × 10 17 cm −3 is observed along with the appearance of two acceptor bound exciton lines typical for Mg-doped GaN. The DBE ionization due to local electric fields in compensated GaN may explain the transformation of the NBG emission

  3. Theoretical study on the spectroscopic properties of CO3(*-).nH2O clusters: extrapolation to bulk.

    Pathak, Arup K; Mukherjee, Tulsi; Maity, Dilip K

    2008-10-24

    Vertical detachment energies (VDE) and UV/Vis absorption spectra of hydrated carbonate radical anion clusters, CO(3)(*-).nH(2)O (n=1-8), are determined by means of ab initio electronic structure theory. The VDE values of the hydrated clusters are calculated with second-order Moller-Plesset perturbation (MP2) and coupled cluster theory using the 6-311++G(d,p) set of basis functions. The bulk VDE value of an aqueous carbonate radical anion solution is predicted to be 10.6 eV from the calculated weighted average VDE values of the CO(3)(*-).nH(2)O clusters. UV/Vis absorption spectra of the hydrated clusters are calculated by means of time-dependent density functional theory using the Becke three-parameter nonlocal exchange and the Lee-Yang-Parr nonlocal correlation functional (B3LYP). The simulated UV/Vis spectrum of the CO(3)(*-).8H(2)O cluster is in excellent agreement with the reported experimental spectrum for CO(3)(*-) (aq), obtained based on pulse radiolysis experiments.

  4. Photodetachment and UV-Vis spectral properties of Cl2rad -·nHO clusters: Extrapolation to bulk

    Pathak, A. K.; Mukherjee, T.; Maity, D. K.

    2008-03-01

    Vertical detachment energy (VDE) and UV-Vis spectra of Cl2rad -·nHO clusters ( n = 1-11) are reported based on first principle electronic structure calculations. VDE of the hydrated clusters are calculated following second order Moller-Plesset perturbation (MP2) as well as coupled cluster theory with 6-311++G(d,p) set of basis function. The excess electron in these hydrated clusters is mainly localized over the solute Cl atoms. A linear relationship is obtained for VDE vs. ( n + 2.6) -1/3 and bulk VDE of Cl2rad - aqueous solution is calculated as 10.61 eV at CCSD(T) level of theory. UV-Vis spectra of these hydrated clusters are calculated applying CI with single electron (CIS) excitation procedure. Simulated UV-Vis spectra of Cl2rad -·10HO cluster is noted to be in excellent agreement with the reported spectra of Cl2rad - (aq) system, λmax for Cl2rad -·11HO system is calculated to be red shifted though.

  5. Magnetic properties and critical current density of bulk MgB2 polycrystalline with Bi-2212 addition

    Shen, T M; Li, G; Zhu, X T; Cheng, C H; Zhao, Y

    2005-01-01

    Bulk samples of MgB 2 were prepared with 0, 3, 5, and 10 wt% Bi 2 Sr 2 CaCu 2 O 8 (Bi-2212) particles, added using a simple solid-state reaction route in order to investigate the effect of inclusions of a material with higher T c than the superconducting matrix. The density, diamagnetic signal, and critical current density, J c , of the samples change significantly with the doping level. It is found that J c is significantly enhanced by the Bi-2212 addition. Microstructural analysis indicates that a small amount of Bi-2212 is decomposed into Cu 2 O and other impurity phases while a significant amount of unreacted Bi-2212 particles remains in MgB 2 matrix, and these act as effective pinning centres for vortices. The enhanced pinning force is mainly attributable to these highly dispersed inclusions inserted in the MgB 2 grains. Despite the effectiveness of the high-T c inclusions in increasing superconducting critical currents in our experiment, our results seem to demonstrate the superiority of attractive centres over repulsive ones. A pinning mechanism is proposed to account for the contribution of this type of pinning centre in MgB 2 superconductors. (rapid communication)

  6. Effects of alkyl chain length and substituent pattern of fullerene bis-adducts on film structures and photovoltaic properties of bulk heterojunction solar cells.

    Tao, Ran; Umeyama, Tomokazu; Kurotobi, Kei; Imahori, Hiroshi

    2014-10-08

    A series of alkoxycarbonyl-substituted dihydronaphthyl-based [60]fullerene bis-adduct derivatives (denoted as C2BA, C4BA, and C6BA with the alkyl chain of ethyl, n-butyl, and n-hexyl, respectively) have been synthesized to investigate the effects of alkyl chain length and substituent pattern of fullerene bis-adducts on the film structures and photovoltaic properties of bulk heterojunction polymer solar cells. The shorter alkyl chain length caused lower solubility of the fullerene bis-adducts (C6BA > C4BA > C2BA), thereby resulting in the increased separation difficulty of respective bis-adduct isomers. The device performance based on poly(3-hexylthiophene) (P3HT) and the fullerene bis-adduct regioisomer mixtures was enhanced by shortening the alkyl chain length. When using the regioisomerically separated fullerene bis-adducts, the devices based on trans-2 and a mixture of trans-4 and e of C4BA exhibited the highest power conversion efficiencies of ca. 2.4%, which are considerably higher than those of the C6BA counterparts (ca. 1.4%) and the C4BA regioisomer mixture (1.10%). The film morphologies as well as electron mobilities of the P3HT:bis-adduct blend films were found to affect the photovoltaic properties considerably. These results reveal that the alkyl chain length and substituent pattern of fullerene bis-adducts significantly influence the photovoltaic properties as well as the film structures of bulk heterojunction solar cells.

  7. Effect of sintering pressure on structure and magnetic properties of Zn0.99Ni0.01O bulk samples synthesized under different pressures

    Wang, Yongqiang; Yuan, Chaosheng; Su, Lei; Wang, Zheng; Hao, Junhong; Ren, Yufen

    2015-01-01

    A series of Zn 0.99 Ni 0.01 O bulk samples were prepared by a coprecipitation method, and then sintered at 600 °C under various pressures from normal pressure(NP) to 3 GPa. The effects of sintering pressure (P S ) on the structure, morphology and magnetic properties of the doping samples were investigated in detail. The XRD and HRTEM results reveal that all samples are of single-phase hexagonal structure. Compared with the sample sintered at normal pressure, the lattice parameters a and c of the samples sintered at high pressures (HP) show a sharply decrease. With the increase of sintering pressure, the particle size gradually increases as well as the particles get closer to each other. At 300 K, the sample sintered at normal pressure shows a superparamagnetic-like behavior, while the samples sintered at high pressures display typical ferromagnetic behaviors. The saturation magnetization of the samples sintered at high pressures is three orders of magnitude larger than that of the one sintered at normal pressure. Our results reveal that an appropriate sintering pressure can tune the magnetic properties of Ni-doped ZnO system by changing the lattice parameters, particle size and inter-particle spacing, which may be helpful to the practical applications. - Highlights: • A series of Zn 0.99 Ni 0.01 O bulk samples were sintered in different pressures. • The lattice constants of the samples sintered at high pressure clearly decrease. • The particle size increases gradually with the increase of sintering pressure. • The samples sintered at different pressures show different magnetic behaviors. • Appropriate sintering pressure can tune the magnetic properties of Zn–Ni–O system

  8. The effect of Al substitution on thermal and mechanical properties of Fe-based bulk metallic glass

    Ma, R.D.; Zhang, H.F.; Yu, H.S.; Hu, Z.Q.

    2008-01-01

    In this paper, a systematic investigation about the effect of Al substitution on properties of Fe-Cr-Mo-Er-C-B amorphous material, including glass-forming ability (GFA), thermal properties, and mechanical properties was presented. It was found out by X-ray diffraction (XRD) that the glass-forming ability decreased with the increase of Al, when Al reached 7 at%, fully amorphous specimen was not obtained. With regard to thermal parameters, such as glass transition temperature T g , crystallization temperature T x , supercooled liquid region ΔT x , and reduced glass temperature T rg were checked by differential scanning calorimeter. A rather wide supercooled liquid region more than 40 K was found. During compression test, results showed Al substitution slightly improved the fracture strength from 3.4 to 3.7 GPa. The fracture morphology was observed by scanning electron microscopy. Micrographs showed the same cleavage-like fracture in spite of different Al substitution

  9. Effect of helium irradiation on deuterium permeation behavior in tungsten

    Uemura, Yuki; Sakurada, Shodai; Fujita, Hiroe; Azuma, Keisuke; Zhou, Quilai [Graduate School of Science & Technology, Shizuoka University, 836 Ohya, Suruga, Shizuoka, 422-8529 Japan (Japan); Hatano, Yuji [Hydrogen Isotope Research Center, University of Toyama, 3190 Gofuku, Toyama, 930-8555 Japan (Japan); Yoshida, Naoaki; Watanabe, Hideo [Institute for Applied Mechanics, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka, 816-8580 Japan (Japan); Oyaizu, Makoto; Isobe, Kanetsugu [National Institutes for Quantum and Radiological Science and Technology, 2166 Obuchi, Rokkasho, Aomori, 039-3212 Japan (Japan); Shimada, Masashi [Idaho National Laboratory, 1955 N. Fremont Avenue, Idaho Falls, ID 83415 (United States); Buchenauer, Dean; Kolasinski, Robert [Sandia National Laboratories, Chemistry, Combustion and Materials Center, Livermore, CA 94550 (United States); Chikada, Takumi [Graduate School of Science & Technology, Shizuoka University, 836 Ohya, Suruga, Shizuoka, 422-8529 Japan (Japan); Oya, Yasuhisa, E-mail: oya.yasuhisa@shizuoka.ac.jp [Graduate School of Science & Technology, Shizuoka University, 836 Ohya, Suruga, Shizuoka, 422-8529 Japan (Japan)

    2017-07-15

    In this study, we measured deuterium (D) gas-driven permeation through tungsten (W) foils that had been pre-damaged by helium ions (He{sup +}). The goal of this work was to determine how ion-induced damage affects hydrogen isotope permeation. At 873 K, the D permeability for W irradiated by 3.0 keV He{sup +} was approximately one order of magnitude lower than that for un-damaged W. This difference diminished with increasing temperature. Even after heating to 1173 K, the permeability returned to less than half of the value measured for un-damaged W. We propose that this is due to nucleation of He bubbles near the surface which potentially serve as a barrier to diffusion deeper into the bulk. Exposure at higher temperatures shows that the D permeability and diffusion coefficients return to levels observed for undamaged material. It is possible that these effects are linked to annealing of defects introduced by ion damage, and whether the defects are stabilized by the presence of trapped He.

  10. Skin penetration and tissue permeation after topical administration of diclofenac.

    Hagen, Martina; Baker, Mark

    2017-09-01

    Topical delivery of drugs is an alternative to oral administration, often with similar efficacy but potentially a more favorable tolerability profile. However, topical formulations need to be able to penetrate the skin and permeate to the target areas in quantities sufficient to exert a therapeutic effect. Many factors can affect this process, including the physicochemical properties of the drug, the formulation used, and the site and mode of application. It is believed that measurement of drug concentrations at the sites of action may be an indicator of their likely efficacy. This review addresses these issues, with reference to topically administered diclofenac in osteoarthritis. Articles relevant to this review were identified after a systematic search of Medline and Embase, using the key words "diclofenac", "topical administration" and "osteoarthritis" in the search strategy. The sparse data available indicate that topical diclofenac can penetrate and permeate to deeper tissues, with a lower plasma to tissue ratio than oral diclofenac. The tissue diclofenac levels after topical delivery are sustained over time (at least several hours). However, there is not enough data to establish how diclofenac levels in the joint compare with IC 50 levels (50% of the maximum inhibition of prostaglandin synthesis) established following oral administration. After topical application, diclofenac can penetrate the skin and permeate to deeper tissues, where it reaches a concentration that appears to be sufficient to exert a therapeutic effect. More robust methods are required for in vivo characterization to better estimate the clinical efficacy of topically applied drugs.

  11. Determination of electronic and atomic properties of surface, bulk and buried interfaces: Simultaneous combination of hard X-ray photoelectron spectroscopy and X-ray diffraction

    Rubio-Zuazo, J., E-mail: rubio@esrf.fr [SpLine, Spanish CRG BM25 Beamline at the ESRF, ESRF, B.P. 220, F-38043 Grenoble (France); Instituto de Ciencia de Materiales de Madrid, ICMM, CSIC, Cantoblanco, E-28049 Madrid (Spain); Castro, G.R. [SpLine, Spanish CRG BM25 Beamline at the ESRF, ESRF, B.P. 220, F-38043 Grenoble (France); Instituto de Ciencia de Materiales de Madrid, ICMM, CSIC, Cantoblanco, E-28049 Madrid (Spain)

    2013-10-15

    Highlights: •We have developed a novel and exceptional tool for non-destructive characterization of bulk and buried interfaces that combine XRD and HAXPES. •We studied the correlation between the atomic, electronic and transport properties of oxygen deficient manganite thin films. •The diffraction data showed a cooperative tilt of the MnO{sub 6} block along the out-of-plane direction. •We shown the absence of the conventional basal plane rotation for the oxygen deficient samples. -- Abstract: Hard X-ray photoelectron spectroscopy (HAXPES) is a powerful novel emerging technique for bulk compositional, chemical and electronic properties determination in a non-destructive way. It benefits from the exceptionally large escape depth of high kinetic energy photoelectrons enabling the study of bulk and buried interfaces up to several tens of nanometres depth. Its advantage over conventional XPS is based on the long mean free path of high kinetic energetic photoelectrons. Using the advantage of tuneable X-ray radiation provided by synchrotron sources the photoelectron kinetic energy, i.e. the information depth can be changed and consequently electronic and compositional depth profiles can be obtained. The combination of HAXPES with an atomic structure sensitive technique, as X-ray diffraction, opens a new research field with great potential for many systems in which their electronic properties are intimately linked to their crystallographic structure. At SpLine, the Spanish CRG Beamline at the European Synchrotron Radiation Facility (ESRF) we have developed a novel and exceptional set-up that combine grazing incidence X-ray diffraction (GIXRD) and HAXPES. Both techniques can be operated simultaneously on the same sample and using the same excitation source. The set-up includes a heavy 2S+3D diffractometer and UHV chamber equipped with an electrostatic analyzer. The UHV chamber has also MBE evaporation sources, an ion gun, a LEED optic, a sample heating and cooling

  12. Structural, chemical, and thermoelectric properties of Bi2Te3 Peltier materials. Bulk, thin films, and superlattices

    Peranio, Nicola

    2008-01-01

    In this work, the nature of the natural nanostructure (nns) was analysed and the correlations to the transport coefficients, particularly the lattice thermal conductivity, is discussed. Experimental methods are presented for the first time, yielding an accurate quantitative analysis of the chemical composition and of stress fields in Bi 2 Te 3 and in compounds with similar structural and chemical microstructures. This work can be subdivided as follows: (I) N-type Bi 2 (Te 0.91 Se 0.09 ) 3 and p-type (Bi 0.26 Sb 0.74 ) 1.98 (Te 0.99 Se 0.01 ) 3.02 bulk materials synthesised by the Bridgman technique. (II) Bi 2 Te 3 thin films and Bi 2 Te 3 /Bi 2 (Te 0.88 Se 0.12 ) 3 superlattices epitaxially grown by molecular beam epitaxy (MBE) on BaF 2 substrates with periods of δ-12 nm at the Fraunhofer-Institut fuer Physikalische Messtechnik (IPM). (III) Experimental methods, i.e., TEM specimen preparation, high-accuracy quantitative chemical analysis by EDX in the TEM, and image simulations of dislocations and the nns according to the two-beam dynamical diffraction theory. The nns was analysed in detail by stereomicroscopy and by image simulation and was found to be a pure sinusoidal displacement field with (i) a displacement vector parallel to and an amplitude of about 10 pm and (ii) a wave vector parallel to {1,0,10} and a wavelength of 10 nm. The results obtained here showed a significant amount of stress in the samples, induced by the nns which was still not noticed and identified. Both kinds of nanostructures, artificial (ans) and natural (nns) nanostructures, yielded in thermoelectric materials a low lattice thermal conductivity which was beneficial for the thermoelectric figure of merit ZT. (orig.)

  13. Optical and terahertz measurement techniques for flat-faced pharmaceutical tablets: a case study of gloss, surface roughness and bulk properties of starch acetate tablets

    Juuti, M; Tuononen, H; Kontturi, V; Peiponen, K-E; Prykäri, T; Alarousu, E; Myllylä, R; Kuosmanen, M; Ketolainen, J

    2009-01-01

    Surface and bulk properties of flat-faced starch acetate tablets were studied. For surface quality inspection optical coherence tomography and recently developed diffractive glossmeter were utilized. Both these optical devices together provide local information on surface roughness and gloss of a tablet over a measured area. The concepts of mean topography and mean gloss profile for surface quality of a tablet are introduced. It was observed that the surface quality of the tablet varies, and compression at high pressure may not guarantee a good surface quality of the tablet. Using novel statistical parameters for gloss and relevant surface roughness parameter, it is possible to get more comprehensive quantitative data on the surface condition of a tablet. THz spectrometer was utilized for detection of THz pulse delay in transmission measurement mode from the tablets. The delay time and thickness ratio of the tablet are consistent with the porosity of the tablet as a function of compression pressure. We suggest that the multimeasurement scheme using three different devices helps tablet makers to better assess bulk and surface quality of their products

  14. Evaluation of whey, milk, and delactosed permeates as salt substitutes.

    Smith, S T; Metzger, L; Drake, M A

    2016-11-01

    Whey and milk permeates are by-products of high-protein dairy powder manufacture. Previous work has shown that these permeates contribute to salty taste without contributing significantly to sodium content. The objective of this study was to explore the sensory characteristics and compositional analysis of permeates from different milk and whey streams and a low-sodium product application made from them. Skim milk, Cheddar, cottage, and Mozzarella cheese whey permeates were manufactured in triplicate, and delactosed whey permeate was obtained in triplicate. Composition (protein, fat, solids, minerals) was conducted on permeates. Organic acid composition was determined using HPLC. Volatile compounds were extracted from permeates by solid phase microextraction with gas chromatography-mass spectrometry. A trained sensory panel documented sensory attributes of permeates and cream of broccoli soups with and without salt or permeates followed by consumer acceptance testing (n=105) on the soups. Cottage cheese whey permeate contained a higher lactic acid content than other permeates, which has been shown to contribute to a higher salty taste. Cottage cheese whey permeate also contained potato or brothy and caramel flavors and sour and salty tastes, whereas delactosed whey permeate had high intensities of cardboard and beefy or brothy flavors and salty taste. Milk, Cheddar, and Mozzarella cheese whey permeates were characterized by sweet taste and cooked milky flavor. Permeates with higher cardboard flavor had higher levels of aldehydes. All permeates contributed to salty taste and to salty taste perception in soups; although the control soup with added salt was perceived as saltier and was preferred by consumers over permeate soups. Soup with permeate from cottage cheese was the least liked of all soups, likely due to its sour taste. All other permeate soups scored at parity for liking. These results demonstrate the potential for milk, whey, and delactosed permeates from

  15. Tritium permeation barriers for fusion technology

    Perujo, A.; Forcey, K.

    1994-01-01

    An important issue concerning the safety, feasibility and fueling (i.e., tritium breeding ratio and recovery from the breeding blanket) of a fusion reactor is the possible tritium leakages through the structural materials and in particular through those operating at high temperatures. The control of tritium permeation could be a critical factor in determining the viability of a future fusion power reactor. The formation of tritium permeation barriers to prevent the loss of tritium to the coolant by diffusion though the structural material seems to be the most practical method to minimize such losses. Many authors have discussed the formation of permeation barriers to reduce the leakage of hydrogen isotopes through proposed first wall and structural materials. In general, there are two routes for the formation of such a barrier, namely: the growth of oxide layers (e.g., Cr 2 O 3 , Al 2 O 3 , etc.) or the application of surface coatings. Non-metals are the most promising materials from the point of view of the formation of permeation barriers. Oxides such as Al 2 O 3 or Cr 2 O 3 or carbides such as SiC or TiC have been proposed. Amongst the metals only tungsten or gold are sufficiently less permeable than steel to warrant investigation as candidate materials for permeation barriers. It is of course possible to grow oxide layers on steel directly by heating in the atmosphere or under a variety of conditions (first route above). The direct oxidizing is normally done in an environment of open-quotes wet hydrogenclose quotes to promote the growth of chromia on, for example, nickel steels or ternary oxides on 316L to prevent corrosion. The application of surface layers (second route above), offers a greater range of materials for the formation of permeation barriers. In addition to reducing permeation, such layers should be adhesive, resistant to attack by corrosive breeder materials and should not crack during thermal cycling

  16. Isothermal Stability and Selected Mechanical Properties of Zr48Cu36Al8Ag8 Bulk Metallic Glass

    Błyskun P.

    2017-09-01

    Full Text Available The aim of this work was to investigate the influence of isothermal annealing on the amorphous structure stability of the Zr48Cu36Al8Ag8 alloy. A series of continuous heating examinations was performed on the differential scanning calorimeter in order to determine the temperature limits for isothermal annealing series where the time to crystallization was measured. The obtained results were calculated and a time-temperature-transformation diagram was created and discussed. Static compression test as well as microhardness measurements of the as-quenched samples gave a mechanical properties results supplement. The measured properties (σc = 1800 MPa and 614 HV0.05 are comparable to the literature results for this alloy. Fractographic observations with the scanning electron microscope were also performed in order to prove some plasticity observed during the strength tests.

  17. Growth and physical properties of top-seeded infiltration growth processed large grain (Gd, Dy)BCO bulk superconductors

    Naik, S.P.K.; Muralidhar, M.; Jirsa, Miloš; Murakami, M.

    2017-01-01

    Roč. 122, č. 19 (2017), s. 1-10, č. článku 193902. ISSN 0021-8979 Institutional support: RVO:68378271 Keywords : silver sheathed superconducting tapes * thick REBaCuO films * electromagnetic properties * solid phase -liquid phase reaction Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 2.068, year: 2016

  18. Bulk dielectric and magnetic properties of PFW-PZT ceramics: absence of magnetically switched-off polarization

    Kempa, Martin; Kamba, Stanislav; Savinov, Maxim; Maryško, Miroslav; Frait, Zdeněk; Vaněk, Přemysl; Tomczyk, M.; Vilarinho, P. M.

    2010-01-01

    Roč. 22, č. 44 (2010), 445902/1-445902/5 ISSN 0953-8984 R&D Projects: GA ČR(CZ) GA202/09/0682 Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z10100521 Keywords : dielectric and magnetic properties * ceramics * polarization * phase transitions Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.332, year: 2010

  19. The effect of various quantum mechanically derived partial atomic charges on the bulk properties of chloride-based ionic liquids

    Zolghadr, Amin Reza, E-mail: arzolghadr@shirazu.ac.ir [Department of Chemistry, Shiraz University, Shiraz 71946-84795 (Iran, Islamic Republic of); Ghatee, Mohammad Hadi [Department of Chemistry, Shiraz University, Shiraz 71946-84795 (Iran, Islamic Republic of); Moosavi, Fatemeh [Department of Chemistry, Ferdowsi University of Mashhad, Mashhad 91779 (Iran, Islamic Republic of)

    2016-08-22

    Partial atomic charges using various quantum mechanical calculations for [C{sub n}mim]Cl (n = 1, 4) ionic liquids (ILs) are obtained and used for development of molecular dynamics simulation (MD) force fields. The isolated ion pairs are optimized using HF, B3LYP, and MP2 methods for electronic structure with 6-311++G(d,p) basis set. Partial atomic charges are assigned to the atomic center with CHELPG and NBO methods. The effect of these sets of partial charges on the static and dynamic properties of ILs is evaluated by performing a series of MD simulations and comparing the essential thermodynamic properties with the available experimental data and available molecular dynamics simulation results. In contrast to the general trends reported for ionic liquids with BF{sub 4}, PF{sub 6}, and iodide anions (in which restrained electrostatic potential (RESP) charges are preferred), partial charges derived by B3LYP-NBO method are relatively good in prediction of the structural, dynamical, and thermodynamic energetic properties of the chloride based ILs.

  20. Bulk dielectric and magnetic properties of PFW-PZT ceramics: absence of magnetically switched-off polarization.

    Kempa, M; Kamba, S; Savinov, M; Maryško, M; Frait, Z; Vaněk, P; Tomczyk, M; Vilarinho, P M

    2010-11-10

    We investigated ceramics samples of solid solutions of [PbFe(2/3)W(1/3)O(3)](x)-[PbZr(0.53)Ti(0.47)O(3)](1 - x) (PFW(x)-PZT(1 - x), x = 0.2 and 0.3) by means of broad-band dielectric spectroscopy, differential scanning calorimetry and SQUID magnetometry. We did not confirm the observations of Kumar et al (2009 J. Phys.: Condens. Matter 21 382204), who reported on reversible suppression of ferroelectric polarization in polycrystalline PFW(x)-PZT(1 - x) thin films for magnetic fields above 0.5 T. We did not observe any change of ferroelectric polarization with external magnetic fields up to 3.2 T. Pirc et al (2009 Phys. Rev. B 79 214114) developed a theory explaining the reported large magnetoelectric effect in PFW(x)-PZT(1 - x), taking into account relaxor magnetic and relaxor ferroelectric properties of the system. Our data revealed classical ferroelectric properties below 525 K and 485 K in samples with x = 0.2 and 0.3, respectively. Moreover, paramagnetic behavior was observed down to 4.5 K instead of previously reported relaxor magnetic behavior. It seems that the reported switching-off of ferroelectric polarization in PFW(x)-PZT(1 - x) thin films is not an intrinsic property, but probably an effect of electrodes, interlayers, grain boundaries or second phases presented in polycrystalline thin films.

  1. The bulk composition and leaching properties of electroplating sludge prior/following the solidification/stabilization by calcium oxide.

    Orescanin, Visnja; Mikulic, Nenad; Mikelic, Ivanka Lovrencic; Posedi, Mario; Kampic, Stefica; Medunic, Gordana

    2009-10-01

    Eighteen samples of electroplating sludge were taken from three vertical profiles of waste storage pond of the zinc plating facility. Dry matter and organic matter content, pH value, bulk concentrations and leachate composition were determined. A sludge sample with the highest zinc value in the leachate was treated with calcium oxide (10% to 70%) and the obtained solidificate was repeatedly tested. There were found significant variations of all measured parameters among the profiles of untreated waste. Dry matter content varied from 125 to 455 mgg(-1), organic matter varied from 94.3 to 293.9 mgg(-1), and pH value varied from 3.42 to 5.90 (mean 4.34). Iron content ranged from 38.4 to 191.4 mgg(-1) (mean 136 mgg(-1); RSD 0.25), while zinc ranged from 10.9 to 58.2 mgg(-1) (mean 33.4 mgg(-1); RSD 0.38). According to its DIN38414-S4 leachate composition, this material was not suitable for landfilling of inert waste since zinc and nickel mean values were 10 and 1.5 times higher, respectively, and maximum values 27 and 2.5 times higher, respectively, compared to the upper permissible limit. Maximum values of Cr(VI), Fe, Ni, Cu, and Zn in the DIN38414-S4 leachate were 0.183 mgL(-1), 34.085 mgL(-1), 1.052 mgL(-1), 0.829 mgL(-1) and 107.475 mgL(-1)L, respectively. Following the solidification/stabilization procedure with CaO (sample/CaO = 90/10), concentrations of Cr(VI), Fe, Cu and Zn were reduced 92, 44, 66 and 57 times, respectively, compared to the untreated sample. The addition of 50% of CaO into the sludge reduced zinc and nickel concentrations 79 and 45 times, respectively, in the DIN38414-S4 leachate of the solidified waste compared to the original sludge, thereby converting an hazardous waste into the inert material suitable for landfilling or reuse in the construction processes.

  2. Influence of Sm2O3 microalloying and Yb contamination on Y211 particles coarsening and superconducting properties of IG YBCO bulk superconductors

    Vojtkova, L.; Diko, P.; Kovac, J.; Vojtko, M.

    2018-06-01

    Single grain YBa2Cu3O7‑x (YBCO or Y123) bulk superconductors were produced by an infiltration growth process. The solid phase precursor was prepared by solid state synthesis from Y2O3 + BaCuO2 powders. The influence of the addition of Sm2O3 and YB contamination from the substrate on the microstructure and superconducting properties was analyzed. The dependences of Yb concentration on the distance from the bottom of the samples measured by energy dispersive spectroscopy microanalysis used in conjunction with scanning electron microscopy confirmed the contamination of the samples during the melting stage of the sample preparation. It is shown that the addition of Sm in low concentration and its combination with Yb from the substrate modify the coarsening of the Y211 particles as well as lead to the appearance of a secondary peak effect in the field dependences of the critical current density.

  3. Ultra-violet absorption induced modifications in bulk and nanoscale electrical transport properties of Al-doped ZnO thin films

    Kumar, Mohit; Basu, Tanmoy; Som, Tapobrata, E-mail: tsom@iopb.res.in [SUNAG Laboratory, Institute of Physics, Sachivalaya Marg, Bhubaneswar 751 005 (India)

    2015-08-07

    Using conductive atomic force microscopy and Kelvin probe force microscopy, we study local electrical transport properties in aluminum-doped zinc oxide (ZnO:Al or AZO) thin films. Current mapping shows a spatial variation in conductivity which corroborates well with the local mapping of donor concentration (∼10{sup 20 }cm{sup −3}). In addition, a strong enhancement in the local current at grains is observed after exposing the film to ultra-violet (UV) light which is attributed to persistent photocurrent. Further, it is shown that UV absorption gives a smooth conduction in AZO film which in turn gives rise to an improvement in the bulk photoresponsivity of an n-AZO/p-Si heterojunction diode. This finding is in contrast to the belief that UV absorption in an AZO layer leads to an optical loss for the underneath absorbing layer of a heterojunction solar cell.

  4. LOW MACH NUMBER MODELING OF CONVECTION IN HELIUM SHELLS ON SUB-CHANDRASEKHAR WHITE DWARFS. II. BULK PROPERTIES OF SIMPLE MODELS

    Jacobs, A. M.; Zingale, M. [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States); Nonaka, A.; Almgren, A. S.; Bell, J. B. [Center for Computational Sciences and Engineering, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2016-08-10

    The dynamics of helium shell convection driven by nuclear burning establish the conditions for runaway in the sub-Chandrasekhar-mass, double-detonation model for SNe Ia, as well as for a variety of other explosive phenomena. We explore these convection dynamics for a range of white dwarf core and helium shell masses in three dimensions using the low Mach number hydrodynamics code MAESTRO. We present calculations of the bulk properties of this evolution, including time-series evolution of global diagnostics, lateral averages of the 3D state, and the global 3D state. We find a variety of outcomes, including quasi-equilibrium, localized runaway, and convective runaway. Our results suggest that the double-detonation progenitor model is promising and that 3D dynamic convection plays a key role.

  5. Electronic-structure origin of the glass-forming ability and magnetic properties in Fe–RE–B–Nb bulk metallic glasses

    Li, J.W.; Estévez, D.; Jiang, K.M.; Yang, W.M.; Man, Q.K.; Chang, C.T.; Wang, X.M.

    2014-01-01

    Highlights: • Relation between GFA and electronic structure of RE doped BMGs is investigated. • Tm enhances RE–B bonds and decreases the density of states near the Fermi level. • Magnetic properties of the alloys are related to the electronic structure of RE. - Abstract: (Fe 0.71 RE 0.05 B 0.24 ) 96 Nb 4 (RE = Gd, Tb, Ho, Er, Tm) bulk metallic glasses (BMGs) were found exhibiting excellent glass-forming ability (GFA) with critical diameters ranging from 3.5 to 6.5 mm, and high compressive fracture strength larger than 4300 MPa. Moreover, they displayed good soft-magnetic properties with saturation magnetic flux density of 0.71–0.87 T, coercive force of 1.23–39.76 A/m and effective permeability of 1500–12,740 at 1 kHz. X-ray photoelectron spectroscopy was performed to clarify the origin of the excellent GFA from the viewpoint of electronic structure. It was found that the Tm doped alloy displayed unique electronic structure including the deepest core-level binding energy, the most numerous RE–B bonds and the minimum density of states near the Fermi level, making this alloy the best glass former. The various trends noticed in the magnetic properties were ascribed mainly to the differences in the magnetic anisotropy and magnetic moment of RE elements

  6. Synthesis and characterization of multiferroic Sm-doped BiFeO{sub 3} nanopowders and their bulk dielectric properties

    Yotburut, Benjaporn [School of Physics, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand); Thongbai, Prasit [Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Yamwong, Teerapon [National Metals and Materials Technology Center (MTEC), Thailand Science Park, Pathumthani 12120 (Thailand); Maensiri, Santi, E-mail: santimaensiri@g.sut.ac.th [School of Physics, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand); SUT Center of Excellence on Advanced Functional Materials, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand)

    2017-09-01

    Highlights: • Bi{sub 1−x}Sm{sub x}FeO{sub 3} nanopowders were prepared by a simple co-precipitation method. • The prepared samples were well characterized by XRD, TEM, SEM, and XAS. • The XANES spectra identified the valence state of Fe ion in all nanopowders as 3+. • Increasing in applied dc bias voltage from 0 to 20 V causes a decrease in the dielectric constant. • The relaxation activation energy of a LFR is larger than that of a HFR. - Abstract: Multiferroic Bi{sub 1−x}Sm{sub x}FeO{sub 3} (x = 0, 0.05, 0.1, 0.2, and 0.3) nanopowders with particle sizes of 69–22.6 nm were prepared by a simple co-precipitation method. The structure and morphology of the samples were examined using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD patterns confirmed the phase transition from rhombohedral to orthorhombic phases. The results of X-ray absorption spectroscopy (XAS) data indicate that the oxidation state of Fe in the sample was Fe{sup 3+}. The results of magnetic properties revealed the enhancement of weak ferromagnetic property with increasing Sm doping in BFO nanopowders. SEM images revealed that the average grain size decreased with an increase in Sm concentration. Undoped BFO ceramics exhibited a high dielectric constant ε′ ∼1.1 × 10{sup 4} and a low loss tangent of tan δ ∼0.5 at room temperature for 1 kHz. The room temperature dielectric constant decreased with increasing concentration of Sm doping and the dielectric relaxation peaks were observed at x ≤ 0.1. The dielectric relaxation peaks which were observed at all frequency ranges were x ≤ 0.1 samples which were attributed to Maxwell-Wagner relaxation. As the temperature increased, great increases in dielectric permittivity were observed in all the Bi{sub 1−x}Sm{sub x}FeO{sub 3} samples. The effects of grain boundaries on the dielectric properties of Sm-doped BFO ceramics were investigated by measuring the dielectric responds in the frequencies of 100 Hz–1

  7. Skin permeation of D-limonene-based nanoemulsions as a transdermal carrier prepared by ultrasonic emulsification.

    Lu, Wen-Chien; Chiang, Been-Huang; Huang, Da-Wei; Li, Po-Hsien

    2014-03-01

    Nanoemulsions can be used for transporting pharmaceutical phytochemicals in skin-care products because of their stability and rapid permeation properties. However, droplet size may be a critical factor aiding permeation through skin and transdermal delivery efficiency. We prepared D-limonene nanoemulsions with various droplet sizes by ultrasonic emulsification using mixed surfactants of sorbitane trioleate and polyoxyethylene (20) oleyl ether under different hydrophilic-lipophilic balance (HLB) values. Droplet size decreased with increasing HLB value. With HLB 12, the droplet size was 23 nm, and the encapsulated ratio peaked at 92.3%. Transmission electron microscopy revealed spherical droplets and the gray parts were D-limonene precipitation incorporated in spherical droplets of the emulsion system. Franz diffusion cell was used to evaluate the permeation of D-limonene nanoemulsion through rat abdominal skin; the permeation rate depended on droplet size. The emulsion with the lowest droplet size (54 nm) achieved the maximum permeation rate. The concentration of D-limonene in the skin was 40.11 μL/cm(2) at the end of 360 min. Histopathology revealed no distinct voids or empty spaces in the epidermal region of permeated rat skin, so the D-limonene nanoemulsion may be a safe carrier for transdermal drug delivery. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Characterisation of bulk solids

    D. McGlinchey [Glasgow Caledonian University, Glasgow (United Kingdom). Centre for Industrial Bulk Solids Handling

    2005-07-01

    Handling of powders and bulk solids is a critical industrial technology across a broad spectrum of industries, including minerals processing. With contributions from leading authors in their respective fields, this book provides the reader with a sound understanding of the techniques, importance and application of particulate materials characterisation. It covers the fundamental characteristics of individual particles and bulk particulate materials, and includes discussion of a wide range of measurement techniques, and the use of material characteristics in design and industrial practice. Contents: Characterising particle properties; Powder mechanics and rheology; Characterisation for hopper and stockpile design; Fluidization behaviour; Characterisation for pneumatic conveyor design; Explosiblility; 'Designer' particle characteristics; Current industrial practice; and Future trends. 130 ills.

  9. Permeation of Comite through protective gloves.

    Zainal, Hanaa; Que Hee, Shane S

    2006-09-01

    The goal of the study was to assess how protective disposable (Safeskin) and chemical protective (Sol-Vex) nitrile gloves were against Comite emulsifiable concentrate formulation containing propargite (PROP) as active pesticidal ingredient, because there were no explicit recommendations for the gloves that should be worn for hand protection. The glove material was exposed in ASTM-type I-PTC-600 permeation cells at 30.0+/-0.5 degrees C, and gas chromatography-mass spectrometry used for PROP analysis. Aqueous solutions of Comite at 40.4 mg/mL permeated both Safeskin and Sol-Vex nitrile by 8h. Safeskin showed a mean PROP mass permeated of 176+/-27 microg after 8h compared with a mean mass permeated for Sol-Vex of 3.17+/-4.08 microg. Thus, Sol-Vex was about 56 times more protective than Safeskin for an 8-h exposure. However, the kinetics of the permeation revealed that Safeskin can be worn for at least 200 min before disposal. When undiluted Comite challenged both types of nitrile, much faster permeation was observed. Safeskin gloves showed two steady state periods. The first had lag times (t(l)) values of about 1h, although normalized breakthrough times (t(b)) were gloves exposed continuously to undiluted Comite permeated above the normalized breakthrough threshold beyond 2.7h. A risk assessment revealed that the PROP skin permeation rate of 7.1 ng cm(-2)h(-1) was much slower than the first steady state Safeskin glove P(s) of 62,000 ng cm(-2)h(-1). Infrared analysis showed that the glove surfaces were not degraded by the Comite challenge. The chemically protective Sol-Vex gloves protected adequately against undiluted formulation for about 2.7h, whereas they provided protection for nearly 8h when the formulation was diluted with water to the highest concentration for field application. In contrast, the disposable Safeskin gloves did not protect at all for the undiluted formulation, but did for 200 min when the formulation was diluted with water to the highest

  10. Effect of pulverization of the bulk powder on the hydration of creatine anhydrate tablets and their pharmaceutical properties.

    Sakata, Yukoh; Shiraishi, Sumihiro; Otsuka, Makoto

    2005-12-10

    The hydration behavior and expansion properties of untreated and pulverized creatine anhydrate (CRA) tablets were studied under 60 and 75%RH at 25 degrees C by using differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD). The tablet hardness of untreated and pulverized CRA tablets was significantly decreased after hydration. There was a linear relationship between the degree of hydration and the tablet hardness of untreated CRA tablets compressed at 1000 kg/cm2. In contrast, the relationship between the degree of hydration and the tablet hardness of pulverized CRA tablets was nonlinear. These results suggest that the reduction in hardness of pulverized CRA tablets does not depend solely on the hydration level of crystal water. PXRD analysis indicated that the diffraction pattern of the pulverized CRA powder was similar to that of the untreated CRA powder. However, the diffraction intensity of the pulverized CRA powder was slightly lower than that of the untreated CRA powder at high angle. The micropore radius of both untreated and pulverized CRA tablets was significantly increased after hydration, but analysis of the relationship between micropore radius and fractional hydration of crystal water showed that untreated CRA tablets were more affected than pulverized CRA tablets. Therefore, the reduction in tablet hardness depends not only on the hydration behavior but also on the crystal orientation of the CRA powder.

  11. Electric transport properties study of bulk BaFe{sub 12}O{sub 19} by complex impedance spectroscopy

    Pattanayak, R., E-mail: ranjit.p20@gmail.com [Department of Physics and Astronomy, National Institute of Technology, Rourkela, Odisha (India); Panigrahi, S. [Department of Physics and Astronomy, National Institute of Technology, Rourkela, Odisha (India); Dash, T. [CSIR-Institute of Minerals and Materials Technology, Bhubaneswar, Odisha (India); Muduli, R.; Behera, D. [Department of Physics and Astronomy, National Institute of Technology, Rourkela, Odisha (India)

    2015-10-01

    Polycrystalline M-type hexagonal Barium ferrite (BaFe{sub 12}O{sub 19}) was prepared by the solid state reaction method. The single phase and well grain growth of micrometer range was confirmed by XRD pattern and SEM image respectively. The presence of Fe{sup 2+} and Fe{sup 3+} states were verified by XPS study. In this report, the electric transport properties of BaFe{sub 12}O{sub 19} (BaM) was systematically investigated and analyzed in the frequency range of 100 Hz to 1 MHz and temperature range of 30–200 °C. The relaxation behaviors were examined by considering both impedance and modulus formalism, to differentiate intrinsic (grain) and extrinsic (grain boundary and electrode polarization) conduction process. The co-contribution effect of grain and grain boundary was verified which appeared as a single relaxation process in the chosen frequency and temperature range. However, the sample experienced the early (even at room temperature) arrival of surface conduction which dominates over grain boundary with increasing of temperature.

  12. Development of a low tritium partial pressure permeation system for mass transport measurement in lead lithium eutectic

    Pawelko, R.; Shimada, M.; Katayama, K.; Fukada, S.; Terai, T.

    2014-01-01

    A new experimental system designed to investigate tritium mass transfer properties in materials important to fusion technology is operational at the Safety and Tritium Applied Research (STAR) facility located at the Idaho National Laboratory (INL). The tritium permeation measurement system was developed as part of the Japan/US TITAN collaboration to investigate tritium mass transfer properties in liquid lead lithium eutectic (LLE) alloy. The system is similar to a hydrogen/deuterium permeation measurement system developed at Kyushu University and also incorporates lessons learned from previous tritium permeation experiments conducted at the STAR facility. This paper describes the experimental system that is configured specifically to measure tritium mass transfer properties at low tritium partial pressures. We present preliminary tritium permeation results for α-Fe and α-Fe/LLE samples at 600degC and at tritium partial pressures between 1.0E-3 and 2.4 Pain helium. The preliminary results are compared with literature data. (author)

  13. In-site coatings to reduce H and Tr permeation

    Stoever, D.; Buchkremer, H.P.; Hecker, R.; Jonas, H.; Schaefer, J.; Zink, U.; Forsyth, N.; Thiele, W.

    1982-01-01

    The main goal of this project is the development of protective coatings to reduce or prevent Tr and H permeation through the heat exchanger walls of HTR components. The tasks of the project are: Measurement of the permeation inhibition efficiency of oxidic coatings on the high-temperature- resistant heat exchanger walls; establishing the parameters influencing permeation by variation of the process gas and steam parameters, temperature and mechanical stress; characterisation of coatings and correlation of coating characteristics with permeation measurements; investigation of permeation and corrosion mechanisms; quantitative description of H and Tr permeation by means of mathematical/physical models. (orig./IHOE) [de

  14. The Effect of Thermal Cycling Treatments on the Thermal Stability and Mechanical Properties of a Ti-Based Bulk Metallic Glass Composite

    Fan Bu

    2016-11-01

    Full Text Available The effect of thermal cycling treatments on the thermal stability and mechanical properties of a Ti48Zr20Nb12Cu5Be15 bulk metallic glass composite (BMGC has been investigated. Results show that moderate thermal cycles in a temperature range of −196 °C (cryogenic temperature, CT to 25 °C (room temperature, RT or annealing time at CT has not induced obvious changes of thermal stability and then it decreases slightly over critical thermal parameters. In addition, the dendritic second phases with a bcc structure are homogeneously embedded in the amorphous matrix; no visible changes are detected, which shows structural stability. Excellent mechanical properties as high as 1599 MPa yield strength and 34% plastic strain are obtained, and the yield strength and elastic modulus also increase gradually. The effect on the stability is analyzed quantitatively by crystallization kinetics and plastic-flow models, and indicates that the reduction of structural relaxation enthalpy, which is related to the degradation of spatial heterogeneity, reduces thermal stability but does not imperatively deteriorate the plasticity.

  15. Bulk and mechanical properties of the Paintbrush tuff recovered from borehole USW NRG-7/7A: Data report. Yucca Mountain Site Characterization Project

    Martin, R.J.; Boyd, P.J.; Noel, J.S.; Price, R.H.

    1995-05-01

    An integral part of the licensing procedure for the potential nuclear waste repository at Yucca Mountain, Nevada, involves prediction of the in situ rheology for the design and construction of the facility and the emplacement of canisters containing radioactive waste. The data used to model the thermal and mechanical behavior of the repository and surrounding lithologies include dry and saturated bulk densities, average grain density, porosity, compressional and shear wave velocities, elastic moduli, and compressional and tensional fracture strengths. In this study, a suite of experiments was performed on cores recovered from the USW NRG-717A borehole drilled in support of the Exploratory Studies Facility (ESF) at Yucca Mountain. USW NRG-7/7A was drilled to a depth of 1,513.4 feet through five thermal/mechanical units of Paintbrush tuff and terminating in the tuffaceous beds of the Calico IEUS. The thermal/mechanical stratigraphy was defined by Orfiz et al. to group rock horizons of similar properties for the purpose of simplifying modeling efforts. The relationship between the geologic stratigraphy and the thermal/mechanical stratigraphy is presented. The tuff samples in this study have a wide range of welding characteristics, and a smaller range of mineralogy and petrology characteristics. Generally, the samples are silicic, ash-fall tuffs that exhibit large variability in their elastic and strength properties

  16. Temperature-dependent dielectric and energy-storage properties of Pb(Zr,Sn,Ti)O{sub 3} antiferroelectric bulk ceramics

    Chen, Xuefeng; Liu, Zhen; Xu, Chenhong; Cao, Fei; Wang, Genshui; Dong, Xianlin, E-mail: xldong@mail.sic.ac.cn [Key laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 200050, Shanghai (China)

    2016-05-15

    The dielectric and energy-storage properties of Pb{sub 0.99}Nb{sub 0.02}[(Zr{sub 0.60}Sn{sub 0.40}){sub 0.95}Ti{sub 0.05}]{sub 0.98}O{sub 3} (PNZST) bulk ceramics near the antiferroelectric (AFE)-ferroelectric (FE) phase boundary are investigated as a function of temperature. Three characteristic temperatures T{sub 0}, T{sub C}, T{sub 2} are obtained from the dielectric temperature spectrum. At different temperature regions (below T{sub 0}, between T{sub 0} and T{sub C}, and above T{sub C}), three types of hysteresis loops are observed as square double loop, slim loop and linear loop, respectively. The switching fields and recoverable energy density all first increase and then decrease with increasing temperature, and reach their peak values at ∼T{sub 0}. These results provide a convenient method to optimize the working temperature of antiferroelectric electronic devices through testing the temperature dependent dielectric properties of antiferroelectric ceramics.

  17. Exploitation of inimitable properties of CuInS2 quantum dots for energy conversion in bulk heterojunction hybrid solar cell

    Jindal, Shikha; Giripunje, Sushama M.

    2017-11-01

    Quantum dots (QDs) are the suitable material for solar cell devices owing to its distinctive optical, electrical and electronic properties. Currently, the most efficient devices have employed the toxic QDs which cause destructive impact on environment. In the present article, we have used environment benign CuInS2 QDs as an acceptor material in bulk heterojunction device of P3HT and QDs. The energy level positions corroborated from UPS spectra substantiates the acceptor property of CuInS2. We scrutinized the hybrid solar cell by tailoring the acceptor content in active layer. The increased acceptor content intensifies the performance of device. The enhancement in photovoltaic parameters is mainly due to the fast dissociation and extraction of photogenerated excitons which occurs with the larger wt% of acceptor QDs. Current density-voltage characteristics describes the greater V oc and I sc in the 60 wt% CuInS2 QDs based solar cell as compared to the low wt% of QDs in the active layer.

  18. An overview of experimental results from ultra-relativistic heavy-ion collisions at the CERN LHC: Bulk properties and dynamical evolution

    Panagiota Foka

    2016-11-01

    Full Text Available The first collisions of lead nuclei, delivered by the CERN Large Hadron Collider (LHC at the end of 2010, at a centre-of-mass energy per nucleon pair sNN= 2.76 TeV, marked the beginning of a new era in ultra-relativistic heavy-ion physics. Following the Run 1 period, LHC also successfully delivered Pb–Pb collisions at the collision energy sNN= 5.02 TeV at the end of 2015. The study of the properties of the produced hot and dense strongly-interacting matter at these unprecedented energies is experimentally pursued by all four big LHC experiments, ALICE, ATLAS, CMS, and LHCb. This review presents selected experimental results from heavy-ion collisions delivered during the first three years of the LHC operation focusing on the bulk matter properties and the dynamical evolution of the created system. It also presents the first results from Run 2 heavy-ion data at the highest energy, as well as from the studies of the reference pp and p–Pb systems, which are an integral part of the heavy-ion programme. Keywords: Large hadron collider, Heavy-ion collisions, High energy physics

  19. Hydrogen and deuterium permeation in copper alloys, copper--gold brazing alloys, gold, and the in situ growth of stable oxide permeation barriers

    Begeal, D.R.

    1978-01-01

    The deuterium permeation through several copper alloys has been measured over a temperature range of 550 to 830 K using the membrane technique. In some cases, the hydrogen permeability was also measured. The results were divided into three categories: common alloys, gold alloys, and stable oxide forming alloys. Common alloys which showed typical bulk metallic diffusion with litle change in the permeation activation energy as compared to copper (77 kJ/mol for D 2 ) were: (additions are in weight percent) 5% Sn, 2.3% U, 0.15% Zr, 4% Sn+4% Pb+4% Zn, 3% Si, and 7% Al+2% Fe. Compared to copper, the D 2 permeability at 573 K was reduced by factors of 2.0, 2.7, 4.5, 5.3, 5.9, and 7.0, respectively. A series of gold--copper alloys including pure gold, 80% Au, 50% Au, 49% Au, and 35% Au also showed typical bulk metallic diffusion with a trend of decreasing permeability (increasing activation energies for permeation) with increasing gold content. There were also pronounced inflections or shifts in the permeability at approx.370 0 C, or about the order--disorder transition for Cu 3 Au and CuAu, for the 80% and 50% alloys. Two alloys did not exhibit bulk metallic permeation behavior and the permeabiltiy was in fact controlled by surface oxide layers. It was found that a layer of beryllium oxide could be formed on Cu+2% Be and a layer of aluminum oxide could be formed on Cu+7% Al+2% Si. As compared to 0.25 mm-thick copper, the deuterium permeability at 500 0 C was reduced by a factor of approx.250 for Cu--Be and approx.1000 for Cu--Al--Si. The activation energies for deuterium permeation were 98 kJ/mol and 132 kJ/mol, respectively. The mechanism for the oxide growth is the high-temperature hydrogen reduction of nearby less stable oxides, simultaneous with oxidation of the active metal, Be or Al, by trace amounts of water in the hydrogen. Ion microprobe mass analysis identified the oxide layers as containing beryllium or aluminum but not containing copper

  20. Investigation of non-magnetic alloys for the suppression of tritium permeation. Final report

    1980-07-01

    This report describes a small (300 man hour) literature survey relating to the suppression of tritium loss by permeation through the walls of fusion reactors. The program was based on prior in-house Thermacore work to suppress hydrogen permeation into high temperature (800 0 C) heat pipes. The Thermacore approach involves selection of a steel with a small (.5 to 5%) aluminum content. The aluminum is diffused to the surface and oxidized. The present work was aimed at identification of alloys which might combine low tritium permeation with other properties desired in fusion reactor vessels, heat exchangers, lithium-handling plumbing and other components likely to contain tritium. These properties include low radiation damage, low magnetic permeability, high temperature strength, and compatibility with potential heat transfer and blanket materials. The work consisted of two tasks: Problem Definition and Literature Search and Analysis

  1. Thermal treatment induced modification of structural, surface and bulk magnetic properties of Fe61.5Co5Ni8Si13.5B9Nb3 metallic glass

    Shah, M.; Satalkar, M.; Kane, S. N.; Ghodke, N. L.; Sinha, A. K.; Varga, L. K.; Teixeira, J. M.; Araujo, J. P.

    2018-05-01

    Effect of thermal annealing induced modification of structural, surface and bulk magnetic properties of Fe61.5Co5Ni8Si13.5B9Nb3 alloy is presented. The changes in properties were observed using synchrotron x-ray diffraction technique (SXRD), atomic force microscopy (AFM), magneto-optical kerr effect (MOKE) and bulk magnetic measurements. Significant variations on the both side of surface occur for the annealing temperature upto 500 °C promotes the surface crystallization. Surface roughness appears due to presence of nanocrystallization plays an important role in determining magnetic properties. Observed lower value of bulk coercivity Hc of 6.2 A/m annealed temperature at 450 °C/1 h ascribed to reduction of disorder as compared to the surface (both shiny and wheel side observed by MOKE measurement) whereas improvement of bulk saturation magnetization with annealing temperature indicates first near neighbor shell of Fe atoms are surrounded by Fe atoms. Evolution of coercivity of surface and bulk with annealing temperature has been presented in conjunction with the structural observations.

  2. Resistance of gloves and protective clothing materials to permeation of cytostatic solutions.

    Krzemińska, Sylwia; Pośniak, Małgorzata; Szewczyńska, Małgorzata

    2018-01-15

    The objective of the work was to determine the resistance of selected protective clothing and glove materials to permeation of cytostatics such as docetaxel, fluorouracil, and doxorubicin. The following glove materials were used: natural rubber latex (code A), acrylonitrile-butadiene rubber (code B) and chloroprene rubber (code C). In addition, we tested a layered material composed of a non-woven polyester (PES), a polypropylene (PP) film, and a non-woven PP used for protective coats (code D). The cytostatics were analyzed by liquid chromatography with diode array detection. The tested samples were placed in a purpose-built permeation cell modified to be different from that specified in the standard EN 6529:2001. The tested materials were characterized by good resistance to solutions containing 2 out of the 3 selected cytostatics: doxorubicin and 5-fluorouracil, as indicated by a breakthrough time of over 480 min. Equally high resistance to permeation of the third cytostatic (docetaxel) was exhibited by natural rubber latex, acrylonitrile-butadiene rubber, and chloroprene rubber. However, docetaxel permeated much more readily through the clothing layered material, compromising its barrier properties. It was found that the presence of additional components in cytostatic preparations accelerated permeation through material samples, thus deteriorating their barrier properties. Int J Occup Med Environ Health 2018;31(3):341-350. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  3. Ultrathin graphene-based membrane with precise molecular sieving and ultrafast solvent permeation

    Yang, Q.; Su, Y.; Chi, C.; Cherian, C. T.; Huang, K.; Kravets, V. G.; Wang, F. C.; Zhang, J. C.; Pratt, A.; Grigorenko, A. N.; Guinea, F.; Geim, A. K.; Nair, R. R.

    2017-12-01

    Graphene oxide (GO) membranes continue to attract intense interest due to their unique molecular sieving properties combined with fast permeation. However, their use is limited to aqueous solutions because GO membranes appear impermeable to organic solvents, a phenomenon not yet fully understood. Here, we report efficient and fast filtration of organic solutions through GO laminates containing smooth two-dimensional (2D) capillaries made from large (10-20 μm) flakes. Without modification of sieving characteristics, these membranes can be made exceptionally thin, down to ~10 nm, which translates into fast water and organic solvent permeation. We attribute organic solvent permeation and sieving properties to randomly distributed pinholes interconnected by short graphene channels with a width of 1 nm. With increasing membrane thickness, organic solvent permeation rates decay exponentially but water continues to permeate quickly, in agreement with previous reports. The potential of ultrathin GO laminates for organic solvent nanofiltration is demonstrated by showing >99.9% rejection of small molecular weight organic dyes dissolved in methanol. Our work significantly expands possibilities for the use of GO membranes in purification and filtration technologies.

  4. Hydrogen permeation through Flinabe fluoride molten salts for blanket candidates

    Nishiumi, Ryosuke, E-mail: r.nishiumi@aees.kyushu-u.ac.jp; Fukada, Satoshi; Nakamura, Akira; Katayama, Kazunari

    2016-11-01

    Highlights: • H{sub 2} diffusivity, solubility and permeability in Flinabe as T breeder are determined. • Effects in composition differences among Flibe, Fnabe and Flinabe are compared. • Changes of pressure dependence of Flinabe permeation rate are clarified. - Abstract: Fluoride molten salt Flibe (2LiF + BeF{sub 2}) is a promising candidate for the liquid blanket of a nuclear fusion reactor, because of its large advantages of tritium breeding ratio and heat-transfer fluid. Since its melting point is higher than other liquid candidates, another new fluoride molten salt Flinabe (LiF + NaF + BeF{sub 2}) is recently focused on because of its lower melting point while holding proper breeding properties. In this experiment, hydrogen permeation behavior through the three molten salts of Flibe (2LiF + BeF{sub 2}), Fnabe (NaF + BeF{sub 2}) and Flinabe are investigated in order to clarify the effects of their compositions on hydrogen transfer properties. After making up any of the three molten salts and purifying it using HF, hydrogen permeability, diffusivity and solubility of the molten salts are determined experimentally by using a system composed of tertiary cylindrical tubes. Close agreement is obtained between experimental data and analytical solutions. H{sub 2} permeability, diffusivity and solubility are correlated as a function of temperature and are compared among the three molten salts.

  5. LIBRETTO-3: modelling tritium extraction/permeation and evaluation of permeation barriers under irradiation

    Sedano, L.A.; Fuetterer, M.A.; Viola, R.; Dies, X.

    1996-01-01

    Permeation barriers are required in order to limit the size and cost of the detritiation plants for future fusion reactor blankets of the water-cooled Pb-17Li type. The LIBRETTO irradiations were performed to evaluate the efficiency of permeation barriers under high flux reactor (HFR) conditions. Tritium extraction and permeation characteristics from Pb-17Li under variable temperatures 553-723 K, H 2 doping (0-1 vol%) and purge gas flow rates 20-100 scc/min were tested in LIBRETTO-3. An external TiC coating, an internal (TiC+Al 2 O 3 ), both produced by chemical vapour deposition (CVD), and an internal Al 2 O 3 produced by pack cementation (PC) on AISI 316L steel were tested as permeation barriers. The release mechanisms, experimental uncertainties and method for permeation barriers qualification are presented. As a result permeation reduction factors (PRF) at 0.1 dpa of 17 and 34 were obtained for the CVD-Al 2 O 3 at 498 K and for the PC-Al 2 O 3 at 508 K, respectively. These values were confirmed by a residence time analysis and are higher than in a preliminary analysis. (orig.)

  6. Effect of Permeation Enhancers on the Release Behavior and ...

    Purpose: The aim of this research work was to formulate, characterize and evaluate the in vitro permeation behavior of tramadol lotion containing propylene glycol (PG) and polyethylene glycol (PEG) as permeation enhancers. Methods: The permeation experiments were conducted in vitro using full thickness rabbit skin in ...

  7. Mechanical properties and fracture mechanism of as-cast Mg77TM12Zn5Y6 (TM = Cu, Ni) bulk amorphous matrix composites

    Qiu, K.Q.; Hu, N.N.; Zhang, H.B.; Jiang, W.H.; Ren, Y.L.; Liaw, P.K.

    2009-01-01

    Comparative investigations on the microstructures, thermal stability and mechanical properties of Mg 77 Cu 12 Zn 5 Y 6 and Mg 77 Ni 12 Zn 5 Y 6 bulk metallic glass matrix composites were carried out by using scanning electron microscopy (SEM), DSC and compressive tester. The results show that the microstructure of as-cast samples with 3 mm in diameter for Cu-containing alloy is consisted of Mg flakes and dotted Mg 2 Cu phase in the amorphous matrix, while the as-cast Ni-containing alloy with the same diameter is mainly consisted of Mg flakes in the amorphous matrix. The glass transition temperature and supercooled liquid region are 413 K and 27 K for the Cu-containing, 443 K and 32 K for the Ni-containing amorphous matrix composites, respectively. The fracture strength, yield strength and plastic strain are 532 MPa, 390 MPa and 2.4% for the Cu-containing alloy, 667 MPa, 412 MPa and 7% for the Ni-containing alloy, respectively. Furthermore, the fracture mechanism for the amorphous matrix composites was discussed according to both the fracture surfaces and the stress-strain curves.

  8. The Effect of Ag Addition on the Enhancement of the Thermal and Mechanical Properties of CuZrAl Bulk Metallic Glasses

    Tsan-Man Chung

    2016-09-01

    Full Text Available In this study, the thermal and mechanical properties of Cu50−xZr43Al7Agx (x = 0, 3, 4, 5, 6 bulk metallic glasses (BMGs are investigated by using an X-ray diffractometer (XRD, a differential scanning calorimeter (DSC, differential thermal analysis (DTA, a Vickers hardness tester, a material test system (MTS, scanning electron microscopy (SEM, and transmission electron microscopy (TEM. Cu50−xZr43Al7Agx (x = 0, 3, 4, 5, 6 BMGs were made by arc-melting and an injection casting process. The results revealed that the glass transition temperature (Tg and the crystallization temperature (Tx of CuZrAl alloy decreased with the Ag addition. Hence, the supercooled liquid region and γ of Cu45Zr43Al7Ag5 alloy increased to 76 K and 0.42, respectively. The thermal stability and glass forming ability of CuZrAlAg BMG alloys were enhanced by the microalloyed Ag content. The room temperature compressive fracture strength and strain measured of Cu47Zr43Al7Ag3 were about 2200 MPa and 2.1%, respectively. The distribution of vein patterns and the formation of nanocrystalline phases on the fracture surface of Cu47Zr43Al7Ag3 alloy can be observed by SEM and TEM to be significant, indicating a typical ductile fracture behavior and an improved plasticity of alloys with the addition of microalloyed Ag from 0 to 6 atom %.

  9. Water Vapor Permeation in Plastics

    Keller, Paul E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kouzes, Richard T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-01-01

    Polyvinyl toluene (PVT) and polystyrene (PS) (referred to as “plastic scintillator”) are used for gamma ray detectors. A significant decrease in radiation detection performance has been observed in some PVT-based gamma-ray detectors in systems in outdoor environments as they age. Recent studies have revealed that plastic scintillator can undergo an environmentally related material degradation that adversely affects gamma ray detection performance under certain conditions and histories. A significant decrease in sensitivity has been seen in some gamma-ray detectors in some systems as they age. The degradation of sensitivity of plastic scintillator over time is due to a variety of factors, and the term “aging” is used to encompass all factors. Some plastic scintillator samples show no aging effects (no significant change in sensitivity over more than 10 years), while others show severe aging (significant change in sensitivity in less than 5 years). Aging effects arise from weather (variations in heat and humidity), chemical exposure, mechanical stress, light exposure, and loss of volatile components. The damage produced by these various causes can be cumulative, causing observable damage to increase over time. Damage may be reversible up to some point, but becomes permanent under some conditions. The objective of this report is to document the phenomenon of permeability of plastic scintillator to water vapor and to derive the relationship between time, temperature, humidity and degree of water penetration in plastic. Several conclusions are documented about the properties of water permeability of plastic scintillator.

  10. High energy-resolution electron energy-loss spectroscopy study of the dielectric properties of bulk and nanoparticle LaB6 in the near-infrared region

    Sato, Yohei; Terauchi, Masami; Mukai, Masaki; Kaneyama, Toshikatsu; Adachi, Kenji

    2011-01-01

    The dielectric properties of LaB 6 crystals and the plasmonic behavior of LaB 6 nanoparticles, which have been applied to solar heat-shielding filters, were studied by high energy-resolution electron energy-loss spectroscopy (HR-EELS). An EELS spectrum of a LaB 6 crystal showed a peak at 2.0 eV, which was attributed to volume plasmon excitation of carrier electrons. EELS spectra of single LaB 6 nanoparticles showed peaks at 1.1-1.4 eV depending on the dielectric effect from the substrates. The peaks were assigned to dipole oscillation excitations. These peak energies almost coincided with the peak energy of optical absorption of a heat-shielding filter with LaB 6 nanoparticles. On the other hand, those energies were a smaller than a dipole oscillation energy predicted using the dielectric function of bulk LaB 6 crystal. It is suggested that the lower energy than expected is due to an excitation at 1.2 eV, which was observed for oxidized LaB 6 area. -- Highlights: → The dielectric properties of LaB 6 nanoparticles applied to solar heat-shielding filters were studied by HR-EELS. → Plasmon peak energies of the LaB 6 nanoparticles were almost equal to optical absorption energy of a heat-shielding filter. → From this result, near-infrared optical absorption of the filter is due to the surface dipole mode of the nanoparticles.

  11. Handling of bulk solids theory and practice

    Shamlou, P A

    1990-01-01

    Handling of Bulk Solids provides a comprehensive discussion of the field of solids flow and handling in the process industries. Presentation of the subject follows classical lines of separate discussions for each topic, so each chapter is self-contained and can be read on its own. Topics discussed include bulk solids flow and handling properties; pressure profiles in bulk solids storage vessels; the design of storage silos for reliable discharge of bulk materials; gravity flow of particulate materials from storage vessels; pneumatic transportation of bulk solids; and the hazards of solid-mater

  12. Permeation tubes. Their use in the preparation of controlled gas atmospheres

    Galianos, J. A.; Palomares, F.

    1981-01-01

    In this paper, the state of the art on the nature, construction and properties of the permeation tubes Is reviewed; after describing the main calibration procedures In use, examples of their application in the area of the atmospheric pollution are given, especially in the case of sulfur dioxides. (Author) 38 refs

  13. A Zr-based bulk metallic glass for future stent applications: Materials properties, finite element modeling, and in vitro human vascular cell response.

    Huang, Lu; Pu, Chao; Fisher, Richard K; Mountain, Deidra J H; Gao, Yanfei; Liaw, Peter K; Zhang, Wei; He, Wei

    2015-10-01

    Despite the prevalent use of crystalline alloys in current vascular stent technology, new biomaterials are being actively sought after to improve stent performance. In this study, we demonstrated the potential of a Zr-Al-Fe-Cu bulk metallic glass (BMG) to serve as a candidate stent material. The mechanical properties of the Zr-based BMG, determined under both static and cyclic loadings, were characterized by high strength, which would allow for the design of thinner stent struts to improve stent biocompatibility. Finite element analysis further complemented the experimental results and revealed that a stent made of the Zr-based BMG was more compliant with the beats of a blood vessel, compared with medical 316L stainless steel. The Zr-based BMG was found to be corrosion resistant in a simulated body environment, owing to the presence of a highly stable ZrO2-rich surface passive film. Application-specific biocompatibility studies were conducted using human aortic endothelial cells and smooth muscle cells. The Zr-Al-Fe-Cu BMG was found to support stronger adhesion and faster coverage of endothelial cells and slower growth of smooth muscle cells than 316L stainless steel. These results suggest that the Zr-based BMG could promote re-endothelialization and potentially lower the risk of restenosis, which are critical to improve vascular stent implantation integration. In general, findings in this study raised the curtain for the potential application of BMGs as future candidates for stent applications. Vascular stents are medical devices typically used to restore the lumen of narrowed or clogged blood vessel. Despite the clinical success of metallic materials in stent-assisted angioplasty, post-surgery complications persist due to the mechanical failures, corrosion, and in-stent restenosis of current stents. To overcome these hurdles, strategies including new designs and surface functionalization have been exercised. In addition, the development of new materials with

  14. Purification Simulation With Vapor Permeation and Distillation-Adsorption In Bioethanol Plant

    Misri Gozan

    2017-04-01

    Full Text Available High purity of Bioethanol is required in biofuel mixing with gasoline (EXX. In bioethanol production line, the azeotropic property of ethanol-water becomes the barrier for purification process. This study examined two bioethanol separation processes by support of simulation tools, Superpro Designer 9.0 software. Ethanol purity and a low costeconomical process were the major considerations. Purification method of vapor permeation membrane technology was compared with distillation-adsorption method. Data from previous lab experiments and some literatures were used. The results showed that distillation-adsorption method is more economical compared to vapor permeation technology. Payback period of the simulation is 3.9 years and 4.3 years to distillation adsorption and vapor permeation respectively with each IRR value is 20.23% and 17.89%. Initial investment value of vapor permeation is 9.6% higher than distillation method. Significant difference observed in operating costs, since more units involved in vapor permeation require more labors to operate.

  15. Investigating the sonophoresis effect on the permeation of diclofenac sodium using 3D skin equivalent.

    Aldwaikat, Mai; Alarjah, Mohammed

    2015-01-01

    Ultrasound temporally increases skin permeability by altering stratum corneum SC function (sonophoresis). The objective of this study was to evaluate the effect of variable ultrasound conditions on the permeation of diclofenac sodium DS with range of physicochemical properties through EpiDerm™. Permeation studies were carried out in vitro using Franz diffusion cell. HPLC method was used for the determination of the concentration of diclofenac sodium in receiving compartment. Parameters like ultrasound frequency, application time, amplitude, and mode of sonication and distance of ultrasound horn from skin were investigated, and the conditions where the maximum enhancement rate obtained were determined. Application of ultrasound enhanced permeation of diclofenac sodium across EpiDerm™ by fivefolds. The most effective enhancing parameters were power sonication of 20kHz frequency, 20% amplitude at continuous mode for 5min. Copyright © 2014. Published by Elsevier B.V.

  16. Effect of phonophoresis on skin permeation of commercial anti-inflammatory gels: sodium diclofenac and ketoprofen.

    Souza, Jaqueline; Meira, Alianise; Volpato, Nadia Maria; Mayorga, Paulo; Gottfried, Carmem

    2013-09-01

    This study evaluated the use of ultrasound in combination with the commercial anti-inflammatory drugs ketoprofen and sodium diclofenac, according to the parameters used in physiotherapy. Ketoprofen and sodium diclofenac were used in the Franz diffusion cell model adapted to an ultrasound transducer in three conditions: no ultrasound, one application of ultrasound and two applications of ultrasound. High-performance liquid chromatography was used to quantify the total amount of drug permeating skin per unit area, as well as flux and latency. The results showed that for ketoprofen, the amount of drug permeating skin and flux increased with two ultrasound applications. Permeation of sodium diclofenac decreased in the presence of ultrasound. Ultrasound parameters and drug properties must be considered in the use of phonophoresis. Copyright © 2013 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  17. Fermentation of lactose to ethanol in cheese whey permeate and concentrated permeate by engineered Escherichia coli.

    Pasotti, Lorenzo; Zucca, Susanna; Casanova, Michela; Micoli, Giuseppina; Cusella De Angelis, Maria Gabriella; Magni, Paolo

    2017-06-02

    Whey permeate is a lactose-rich effluent remaining after protein extraction from milk-resulting cheese whey, an abundant dairy waste. The lactose to ethanol fermentation can complete whey valorization chain by decreasing dairy waste polluting potential, due to its nutritional load, and producing a biofuel from renewable source at the same time. Wild type and engineered microorganisms have been proposed as fermentation biocatalysts. However, they present different drawbacks (e.g., nutritional supplements requirement, high transcriptional demand of recombinant genes, precise oxygen level, and substrate inhibition) which limit the industrial attractiveness of such conversion process. In this work, we aim to engineer a new bacterial biocatalyst, specific for dairy waste fermentation. We metabolically engineered eight Escherichia coli strains via a new expression plasmid with the pyruvate-to-ethanol conversion genes, and we carried out the selection of the best strain among the candidates, in terms of growth in permeate, lactose consumption and ethanol formation. We finally showed that the selected engineered microbe (W strain) is able to efficiently ferment permeate and concentrated permeate, without nutritional supplements, in pH-controlled bioreactor. In the conditions tested in this work, the selected biocatalyst could complete the fermentation of permeate and concentrated permeate in about 50 and 85 h on average, producing up to 17 and 40 g/l of ethanol, respectively. To our knowledge, this is the first report showing efficient ethanol production from the lactose contained in whey permeate with engineered E. coli. The selected strain is amenable to further metabolic optimization and represents an advance towards efficient biofuel production from industrial waste stream.

  18. Improved permeation barriers for tritiated waste packaging

    Vassallo, G.; Van Den Bergh, R.; Forcey, K.S.; Perujo, A.

    1994-01-01

    High-density polyethylene (HDPE) is extensively used as flexible bagging or packaging for soft tritiated waste in the tritium community because of its low permeability to the more radiotoxic form of tritium, i.e., tritiated water (HTO). However, HDPE does not represent a perfect barrier to HTO nor does it effectively hinder the permeation of elemental tritium, i.e, HT. This latter drawback is particularly important considering that the elemental form may readily convert to HTO outside of the waste package. The possible use of a multilayer film as packing material for the conditioning of tritiated waste is assessed, and its capability to hinder the permeation of elemental tritium is measured and compared with that of bare HDPE. The material investigated is readily available from the food industry. 5 refs., 1 tab

  19. Modeling and experiments on tritium permeation in fusion reactor blankets

    Holland, D. F.; Longhurst, G. R.

    The determination of tritium loss from helium-cooled fusion breeding blankets are discussed. The issues are: (1) applicability of present models to permeation at low tritium pressures; (2) effectiveness of oxide layers in reducing permeation; (3) effectiveness of hydrogen addition as a means to lower tritium permeation; and (4) effectiveness of conversion to tritiated water and subsequent trapping to reduce permeation. Theoretical models applicable to these issues are discussed, and results of experiments in two areas are presented; permeation of mixtures of hydrogen isotopes and conversion to tritiated water.

  20. Modeling and experiments on tritium permeation in fusion reactor blankets

    Holland, D.F.; Longhurst, G.R.

    1985-01-01

    Issues are discussed that are critical in determining tritium loss from helium-cooled fusion breeding blankets. These issues are: (a) applicability of present models to permeation at low tritium pressures, (b) effectiveness of oxide layers in reducing permeation, (c) effectiveness of hydrogen addition as a means to lower tritium permeation, and (d) effectiveness of conversion to tritiated water and subsequent trapping as a means to reduce permeation. The paper discusses theoretical models applicable to these issues, and presents results of experiments in two areas: permeation of mixtures of hydrogen isotopes and conversion to tritiated water

  1. Enzymatic hydrolysis of lactose of whey permeate

    Karina Nascimento de Almeida

    2015-09-01

    Full Text Available The whey permeate is the residual of the concentration process of the whey proteins by ultrafiltration method. It contains important nutrients such as lactose, minerals and some proteins and lipids. It is without an ending industrial waste that causes serious damage to the environment. For its full use the lactose must be hydrolyzed to enable its consumption by intolerant people. The enzymatic hydrolysis by lactase (β-galactosidase of Kluyveromyces lactis yeast is a safe method that does not compromise the integrity of other nutrients, enabling further use of the permeate as a raw material. This study aimed to perform tests of enzymatic hydrolysis of lactose in whey permeate formulations in a concentration of 0.2%, 0.7% and 1% at 30, 60 and 90 minutes with pH 6.3 medium and 37 °C. The reactions were monitored by high performance liquid chromatography which showed that the enzyme concentration of 0.7% at time 30 minutes formulations became safe for consumption by lactose intolerant people, according to minimum levels established by law.

  2. Flibe-D2 Permeation Experiment and Analysis

    Fukada, S.; Anderl, R.A.; Pawelko, R.J.; Smolik, G.R.; Schuetz, S.T.; O'Brien, J.E.; Nishimura, H.; Hatano, Y.; Terai, T.; Petti, D.A.; Sze, D.-K.; Tanaka, S.

    2003-01-01

    Experiment of D 2 permeation through Ni facing with purified Flibe is being carried out under the Japan-US joint research project (JUPITER-II). The experiment is proceeding in the following phases; (i) fabrication and assembly of a dual-probe permeation apparatus, (ii) a single-probe Ni/D 2 permeation experiment without Flibe, (iii) a dual-probe Ni/D 2 permeation experiment without Flibe, (iv) Flibe chemical purification by HF/H 2 gas bubbling, (v) physical purification by Flibe transport through a porous Ni filter, (vi) Ni/Flibe/D 2 permeation experiment, and (vii) Ni/Flibe/HT permeation experiment. The present paper describes results of the single and dual Ni/D 2 permeation experiments in detail

  3. Electronic properties and bulk moduli of novel boron nitride polymorphs: hyperdiamond B12N12 and the simple cubic B24N24, B12N12 fulborenites

    Pokrivnyj, V.V.; Bekenev, V.L.

    2006-01-01

    Equation of states, energy band structure, electronic density of states, and bulk moduli of the boron nitride fulborenite crystals: B 12 N 12 with a diamond lattice and B 24 N 24 , B 12 N 12 with a simple cubic lattice have been calculated for the first time by FLAPW method. Calculated parameters of these compounds are as follows: equilibrium lattice parameter, the length of B-N bond, the number of atoms per conventional cell, density, bulk modulus, band gap. Hyperdiamond B 12 N 12 is shown to have the record bulk modulus B 0 = 658 GPa [ru

  4. Effects of the copper content on the structural and electrical properties of Cu{sub 2}ZnSnSe{sub 4} bulks

    Tsega, Moges, E-mail: mogestsega@yahoo.com [Department of Physics, University of the Free State (Qwaqwa Campus), Private Bag X13, Phuthaditjhaba 9866 (South Africa); Department of Physics, Bahir Dar University (Ethiopia); Dejene, F.B.; Koao, L.F. [Department of Physics, University of the Free State (Qwaqwa Campus), Private Bag X13, Phuthaditjhaba 9866 (South Africa)

    2016-01-01

    We have investigated the concept of defect in Cu{sub x}ZnSnSe{sub 4} (x=1.6–2.0) and Cu{sub y}(Zn{sub 0.9}Sn{sub 1.1})Se{sub 4} (y= 1.6–2.0) bulks prepared by liquid-phase sintering at 600 °C for 2 h with soluble sintering aids of Sb{sub 2}S{sub 3} and Te. All samples were found to exhibit p-type semiconductor for Cu{sub x}ZnSnSe{sub 4}, while n-type of behavior obtained at y= 1.8–2.0 for Cu{sub y}(Zn{sub 0.9}Sn{sub 1.1})Se{sub 4} pellets. The Cu vacancy acts as an acceptor point defect to form the p-type semiconductor, and Sn{sup 4+} acts as a donor to form the n-type behavior for the Sn-rich CZTSe. SEM images of pellets show dense surface morphology, and increase in grain size upon Cu inclusion. The largely increased Hall mobility and the slightly changed carrier concentration for Cu{sub y}(Zn{sub 0.9}Sn{sub 1.1})Se{sub 4} with increasing the Cu content is related to the types of its defects. At y=2.0 with carrier concentration of 4.88×10{sup 17} cm{sup −3} showed the highest mobility of around 58 cm{sup 2}/V s. Based upon the proposed point defects, the CZTSe property can be consistently explained.

  5. Co-current Doping Effect of Nanoscale Carbon and Aluminum Nitride on Critical Current Density and Flux Pinning Properties of Bulk MgB2 Superconductors

    Tripathi, D.; Dey, T. K.

    2018-05-01

    The effect of nanoscale aluminum nitride (n-AlN) and carbon (n-C) co-doping on superconducting properties of polycrystalline bulk MgB2 superconductor has been investigated. Polycrystalline pellets of MgB2, MgB2 + 0.5 wt% AlN (nano), MgB_{1.99}C_{0.01} and MgB_{1.99}C_{0.01} + 0.5 wt% AlN (nano) have been synthesized by a solid reaction process under inert atmosphere. The transition temperature (TC) estimated from resistivity measurement indicates only a small decrease for C (nano) and co-doped MgB2 samples. The magnetic field response of investigated samples has been measured at 4, 10, and 20 K in the field range ± 6 T. MgB2 pellets co-doped with 0.5 wt% n-AlN and 1 wt% n-C display appreciable enhancement in critical current density (J_C) of MgB2 in both low (≥ 3 times), as well as, high-field region (≥ 15 times). J_C versus H behavior of both pristine and doped MgB2 pellets is well explained in the light of the collective pinning model. Further, the normalized pinning force density f_p(= F_p/F_{pmax}) displays a fair correspondence with the scaling procedure proposed by Eisterer et al. Moreover, the scaled data of the pinning force density (i.e., f_p{-}h data) of the investigated pellets at different temperature are well interpreted by a modified Dew-Hughes expression reported by Sandu and Chee.

  6. Mechanical properties and microstructure of commercial amorphous golf club heads made of Zr-Ti-Cu-Ni-Be bulk metallic glass

    Choi, Y.C.; Hong, S.I.

    2007-01-01

    Mechanical properties and microstructures of Zr 41.2 Ti 13.8 Cu 12.5 Ni 10 Be 22.5 (numbers indicate at.%) bulk metallic glass taken from commercial golf club heads were investigated at room temperature and 573 K. Transmission electron microscopy (TEM) and differential scanning calorimetry (DSC) indicate that the thin central section of the golf club head is amorphous and the outer rim of the head is crystallized. X-ray diffraction (XRD) analyses revealed the presence of Zr 2 Cu, ZrBe 2 , Cu 2 Ni and BeNi in the rim of the iron head. In the crystallized region, crystalline particles with the size of ∼1 μm were observed. At room temperature, amorphous sample (∼2100 MPa) revealed higher fracture stress than crystallized sample (∼1700 MPa). Crystallized sample fractured in the elastic region whereas the amorphous sample displayed some plasticity corresponding serrated flow before the fracture. The serrated flow region with some plasticity in the amorphous alloy results from strain hardening and repetitive shear band initiation and propagation. The crystallized alloy extracted from the thick part of the club fractured in the elastic region, at a much lower stress level than the amorphous, suggesting that relatively coarse crystal particles formed during cooling cause the brittle fracture. Scanning electron microscope observations revealed that the compressive fracture surface of the samples from the central thin section mainly consisted of vein-like structure, but the samples from the outer rim of the head showed mixture of vein-like structure and featureless brittle fracture morphology. At 573 K, both samples exhibited the decrease of strength and fractured in the elastic region. In this study, the effect of crystallization on the reliability and safety of golf club heads was also examined

  7. First-principles modeling of metal (ii) ferrocyanide: electronic property, magnetism, bulk moduli, and the role of C  ≡  N− defect

    Le, Hung M; Pham, Tan-Tien; Dat, Vo Duy; Kawazoe, Yoshiyuki

    2017-01-01

    The ferrocyanide structures of transition metals (M) Ti 2+ , Cr 2+ , Mn 2+ , or Co 2+ are investigated using a first-principles modeling approach. The crystal structure of cobalt ferrocyanide is found to resemble previous experimental data with good accuracy (∼1% error). The considered porous structures possess magnetic moments of 8.00 µ B /cell, 8.00 µ B /cell, 4.00 µ B /cell, and 4.00 µ B /cell given by the [TiFe(CN) 6 ] 2− , [CrFe(CN) 6 ] 2− , [MnFe(CN) 6 ] 2− , and [CoFe(CN) 6 ] 2− frameworks, respectively. There is only one spin-state occupation at the Fermi level, which leads to the conclusion of semi-metallicity of the four structures. To verify the reliability of the electronic and magnetic properties, linear-response DFT  +   U calculations are performed and establish excellent agreement with the conventional DFT calculations. Then, the mechanical strength is evaluated by estimating the bulk moduli of the four structures, which fall in the range of 114 GPa–133 GPa. Upon the consideration of one C  ≡  N − linker defect, the magnetic moments of cobalt ferrocyanide and manganese ferrocyanide rise dramatically to 8 µ B /cell, while that of the titanium structure drops to 6 µ B /cell. In light of the electronic structure evidence, we believe that the low-spin Fe cation nearby the C  ≡  N − defect has an indirect effect on spin polarization of the four Co cations in the unit cell. (paper)

  8. Crystallization kinetics and magnetic properties of Fe{sub 66}Nb{sub 4}B{sub 30} bulk metallic glass

    Stoica, M., E-mail: m.stoica@ifw-dresden.d [IFW Dresden, Institute for Complex Materials, P.O. Box 270116, D-01171 Dresden (Germany); Kumar, S. [IFW Dresden, Institute for Complex Materials, P.O. Box 270116, D-01171 Dresden (Germany); Roth, S. [IFW Dresden, Institute for Metallic Materials, P.O. Box 270116, D-01171 Dresden (Germany); Ram, S. [Materials Science Centre, Indian Institute of Technology, Kharagpur 721302 (India); Eckert, J. [IFW Dresden, Institute for Complex Materials, P.O. Box 270116, D-01171 Dresden (Germany); Vaughan, G. [European Synchrotron Radiation Facilities ESRF, 38402 Grenoble (France); Yavari, A.R. [LTPCM-CNRS, Institut National Politechnique de Grenoble, 1130 Rue de la Piscine, BP 75, Saint Martin d' Heres Campus 38402 (France)

    2009-08-26

    Fe-based bulk metallic glasses (BMGs) have a high application potential because of their unique soft magnetic properties, mechanical behaviour and high corrosion resistance. Also, they can be obtained directly in the final shape suitable for use as magnetic sensors, magnetic valves, magnetic clutches etc. in different devices. Fe-based alloys able to form magnetic BMGs are of the type transition metal-metalloid and often contain 5 or more elements. Usually, the metalloid content is around 20 at.%. Recently, a new Fe-based BMG containing only 3 elements and a very high boron content was synthesized. The preparation of this BMG was done by employing the copper mold casting method and using the fluxing technique. This new BMG is ferromagnetic, with a Curie temperature around 550 K and a saturation magnetization of 105 Am{sup 2}/kg. Differential scanning calorimetry (DSC) investigations revealed a reduced glass transition temperature of 0.55 and an extension of the supercooled liquid region of about 31 K, values which indicate a relatively good thermal stability. Despite of numerous studies about Fe-based BMGs, there is still a lack of data about the crystallization kinetics. Also, the intermediate metastable phases, which form upon crystallization from the amorphous state, as well as the mechanism of their formation, are not fully understood. The present work discusses the kinetics of the phase formation using the Kissinger analysis and Johnson-Mehl-Avrami plots, correlated with the results obtained upon X-ray diffraction (XRD) of samples with different metastable structures. Additionally, the magnetic behaviour of different phase(s) is presented.

  9. Zirconium based bulk metallic glasses

    Dey, G.K.; Neogy, S.; Savalia, R.T.; Tewari, R.; Srivastava, D.; Banerjee, S.

    2006-01-01

    Metallic glasses have come into prominence in recent times because their nanocrystalline atomic arrangement imparts many useful and unusual properties to these metallic solids. In this study, bulk glasses have been obtained in Zr based multicomponent alloy by induction melting these alloys in silica crucibles and casting these in form of rods 3 and 6 mm in diameter in a copper mould

  10. Structure and soft magnetic properties of the bulk samples prepared by compaction of the mixtures of Co-based and Fe-based powders

    Fuezer, J.; Bednarcik, J.; Kollar, P.; Roth, S.

    2007-01-01

    Ball milling of CoFeZrB ribbons and subsequent compaction of the resulting powders were used to prepare bulk amorphous samples. Further, two sets of powder samples were prepared by cryomilling of FeCuNbMoSiB alloy in amorphous and nanocrystalline state. Amorphous and nanocrystalline FeCuNbMoSiB powders were blended with CoFeZrB powder at different concentrations. Such powder mixtures were consolidated and several bulk nanocomposites have been synthesized. An addition of nanocrystalline or amorphous FeCuNbMoSiB powder to amorphous CoFeZrB powder caused a decrease of the magnetostriction of the resultant bulk samples, while the coercivity shows an opposite behavior. Our results show that the powder consolidation by hot pressing is an alternative method for the preparation of bulk metallic glasses, which are difficult to prepare by casting methods

  11. The ‘ideal selectivity’ vs ‘true selectivity’ for permeation of gas mixture in nanoporous membranes

    He, Zhou; Wang, Kean

    2018-03-01

    In this study, we proposed and validated a novel and non-destructive experimental technology for measuring the permeation of binary gas mixture in nanoporous membranes. The traditional time lag rig was modified to examine the permeation characteristics of each gas component as well as that of the binary gas mixtures. The difference in boiling points of each species were explored. Binary gas mixtures of CO2/He were permeated through the nanoporous carbon molecular sieve membrane (CMSM). The results showed that, due to the strong interaction among different molecules and with the porous network of the membrane, the measured perm-selectivity or ‘true selectivity’ of a binary mixture can significantly deviate from the ‘ideal selectivity’ calculated form the permeation flux of each pure species, and this deviation is a complicated function of the molecular properties and operation conditions.

  12. Modelling the effect of mixture components on permeation through skin.

    Ghafourian, T; Samaras, E G; Brooks, J D; Riviere, J E

    2010-10-15

    A vehicle influences the concentration of penetrant within the membrane, affecting its diffusivity in the skin and rate of transport. Despite the huge amount of effort made for the understanding and modelling of the skin absorption of chemicals, a reliable estimation of the skin penetration potential from formulations remains a challenging objective. In this investigation, quantitative structure-activity relationship (QSAR) was employed to relate the skin permeation of compounds to the chemical properties of the mixture ingredients and the molecular structures of the penetrants. The skin permeability dataset consisted of permeability coefficients of 12 different penetrants each blended in 24 different solvent mixtures measured from finite-dose diffusion cell studies using porcine skin. Stepwise regression analysis resulted in a QSAR employing two penetrant descriptors and one solvent property. The penetrant descriptors were octanol/water partition coefficient, logP and the ninth order path molecular connectivity index, and the solvent property was the difference between boiling and melting points. The negative relationship between skin permeability coefficient and logP was attributed to the fact that most of the drugs in this particular dataset are extremely lipophilic in comparison with the compounds in the common skin permeability datasets used in QSAR. The findings show that compounds formulated in vehicles with small boiling and melting point gaps will be expected to have higher permeation through skin. The QSAR was validated internally, using a leave-many-out procedure, giving a mean absolute error of 0.396. The chemical space of the dataset was compared with that of the known skin permeability datasets and gaps were identified for future skin permeability measurements. Copyright 2010 Elsevier B.V. All rights reserved.

  13. Design of a permeator against vacuum for tritium extraction from eutectic lithium-lead in a DCLL DEMO

    Garcinuño, Belit, E-mail: belit.garcinuno@ciemat.es [CIEMAT-LNF (Laboratorio Nacional de Fusión), Madrid (Spain); Rapisarda, David [CIEMAT-LNF (Laboratorio Nacional de Fusión), Madrid (Spain); Fernández, Iván [Fundación & Departamento de Ingeniería Energética, UNED, Madrid (Spain); CIEMAT-LNF (Laboratorio Nacional de Fusión), Madrid (Spain); Moreno, Carlos; Palermo, Iole; Ibarra, Ángel [CIEMAT-LNF (Laboratorio Nacional de Fusión), Madrid (Spain)

    2017-04-15

    Highlights: • A conceptual design of a Permeator Against Vacuum is presented. • The efficiency is dependent on geometry and Tritium transport. • The use of different membrane materials is discussed. • A squared PAV with alternated PbLi flowing and vacuum flat ducts is designed. • 80% efficiency of Tritium extraction is accomplished under DCLL-BB requirements. - Abstract: One of the most important issues in future fusion power plants is the extraction of tritium generated in the breeders in order to achieve self-sufficiency. When the breeder is a liquid metal one of the most promising techniques is the Permeation Against Vacuum, whose principle is based on tritium diffusion through a permeable membrane in contact with the liquid metal carrier and its further extraction by a vacuum pump. A conceptual design of permeator has been developed, taking into account the features of a DEMO reactor with a Dual Coolant Lithium Lead (DCLL) breeder blanket. The study is based on the analysis of different membranes and geometries aiming at the overall efficiency (extraction capability) of the device, as well as its compatibility with the breeder material. The permeator is based on a rectangular section multi-channel distribution where the liquid metal channels and vacuum channels are alternated in order to maximize the contact area and therefore to promote tritium transport from the bulk to the walls. The resulting permeator design has an excellent estimated extraction efficiency, of 80%, in a relatively compact device.

  14. Modelling of bulk superconductor magnetization

    Ainslie, M D; Fujishiro, H

    2015-01-01

    This paper presents a topical review of the current state of the art in modelling the magnetization of bulk superconductors, including both (RE)BCO (where RE = rare earth or Y) and MgB 2 materials. Such modelling is a powerful tool to understand the physical mechanisms of their magnetization, to assist in interpretation of experimental results, and to predict the performance of practical bulk superconductor-based devices, which is particularly important as many superconducting applications head towards the commercialization stage of their development in the coming years. In addition to the analytical and numerical techniques currently used by researchers for modelling such materials, the commonly used practical techniques to magnetize bulk superconductors are summarized with a particular focus on pulsed field magnetization (PFM), which is promising as a compact, mobile and relatively inexpensive magnetizing technique. A number of numerical models developed to analyse the issues related to PFM and optimise the technique are described in detail, including understanding the dynamics of the magnetic flux penetration and the influence of material inhomogeneities, thermal properties, pulse duration, magnitude and shape, and the shape of the magnetization coil(s). The effect of externally applied magnetic fields in different configurations on the attenuation of the trapped field is also discussed. A number of novel and hybrid bulk superconductor structures are described, including improved thermal conductivity structures and ferromagnet–superconductor structures, which have been designed to overcome some of the issues related to bulk superconductors and their magnetization and enhance the intrinsic properties of bulk superconductors acting as trapped field magnets. Finally, the use of hollow bulk cylinders/tubes for shielding is analysed. (topical review)

  15. Bulk viscosity and cosmological evolution

    Beesham, A.

    1996-01-01

    In a recent interesting paper, Pimentel and Diaz-Rivera (Nuovo Cimento B, 109(1994) 1317) have derived several solutions with bulk viscosity in homogeneous and isotropic cosmological models. They also discussed the properties of these solutions. In this paper the authors relate the solutions of Pimentel and Diaz-Rivera by simple transformations to previous solutions published in the literature, showing that all the solutions can be derived from the known existing ones. Drawbacks to these approaches of studying bulk viscosity are pointed out, and better approaches indicated

  16. Preparation, characterization and permeation studies of a nanovesicular system containing diclofenac for transdermal delivery.

    Gaur, Praveen Kumar; Purohit, Suresh; Kumar, Yatendra; Mishra, Shikha; Bhandari, Anil

    2014-02-01

    Transdermal formulations contain permeation enhancer which causes skin damage. Ceramide 2 is natural lipid found in stratum corneum (SC). Drug-loaded nanovesicles of ceramide-2, cholesterol, palmitic acid, cholesteryl sulfate were formulated and analyzed for physical and biological properties. Diclofenac was used as a model drug. The vesicles were prepared using the film hydration method and characterized for physical parameters, in vitro drug release, accelerated stability studies and formulated into gel. Respective gels were compared with a commercial formulation (CEG) and plain carbopol gel (CG) containing drug for ex vivo, in vivo drug permeation and anti-inflammatory activity. The vesicles were stable with optimum physical parameters. DCG-1 showed 92.89% in vitro drug release. Ceramide vesicles showed drug release between 18 and 25 μg/cm(2) whereas CG and CEG released 0.33 and 1.35 μg/cm(2) drug, respectively. DCG-1 and CEG showed corresponding Cmax at 6 and 4 h, respectively. DCG-1 showed six times AUC than CEG. DCG-1 inhibited edema by 86.37% by 4th hour of application. The presence of ceramide 2 specifically promotes the drug permeation through SC and dermis and also contribute towards stability and non-irritancy. The composition of the nanovesicle played an important role in physical properties and drug permeation.

  17. Restoration with pioneer plants changes soil properties and remodels the diversity and structure of bacterial communities in rhizosphere and bulk soil of copper mine tailings in Jiangxi Province, China.

    Sun, Xiaoyan; Zhou, Yanling; Tan, Yinjing; Wu, Zhaoxiang; Lu, Ping; Zhang, Guohua; Yu, Faxin

    2018-05-25

    To unravel the ecological function played by pioneer plants in the practical restoration of mine tailings, it is vital to explore changes of soil characteristics and microbial communities in rhizosphere and bulk soil following the adaptation and survival of plants. In the present study, the diversity and structure of rhizospheric bacterial communities of three pioneer plants in copper mine tailings were investigated by Illumina MiSeq sequencing, and the effects of pioneer plants on soil properties were also evaluated. Significant soil improvement was detected in rhizospheric samples, and Alnus cremastogyne showed higher total organic matter, total nitrogen, and available phosphorus than two other herbaceous plants. Microbial diversity indices in rhizosphere and bulk soil of reclaimed tailings were significantly higher than bare tailings, even the soil properties of bulk soil in reclaimed tailings were not significantly different from those of bare tailings. A detailed taxonomic composition analysis demonstrated that Alphaproteobacteria and Deltaproteobacteria, Chloroflexi, Acidobacteria, and Gemmatimonadetes showed significantly higher relative abundance in rhizosphere and bulk soil. In contrast, Gammaproteobacteria and Firmicutes were abundant in bare tailings, in which Bacillus, Pseudomonas, and Lactococcus made up the majority of the bacterial community (63.04%). Many species within known heavy metal resistance and nutrient regulatory microorganism were identified in reclaimed tailings, and were more abundant among rhizospheric microbes. Hierarchical clustering and principal coordinate analysis (PCoA) analysis demonstrated that the bacterial profiles in the rhizosphere clustered strictly together according to plant types, and were distinguishable from bulk soil. However, we also identified a large shared OTUs that occurred repeatedly and was unaffected by highly diverse soil properties in rhizosphere and bulk samples. Redundancy analysis indicated that water

  18. Microstructural Study on Oxygen Permeated Arc Beads

    Kuan-Heng Liu

    2015-01-01

    Full Text Available We simulated short circuit of loaded copper wire at ambient atmosphere and successfully identified various phases of the arc bead. A cuprous oxide flake was formed on the surface of the arc bead in the rapid solidification process, and there were two microstructural constituents, namely, Cu-κ eutectic structure and solutal dendrites. Due to the arc bead formed at atmosphere during the local equilibrium solidification process, the phase of arc bead has segregated to the cuprous oxide flake, Cu-κ eutectic, and Cu phase solutal dendrites, which are the fingerprints of the arc bead permeated by oxygen.

  19. Hydrogen isotope permeation in elastomeric materials

    Steinmeyer, R.H.; Braun, J.D.

    1976-01-01

    The permeabilities of elastomeric and polymeric materials to hydrogen isotopes were measured at room temperature. The technique for measuring permeation rates is based on the following constant-volume method: a fixed pressure of gas is applied to one side of the specimen to be studied and the permeability constant is determined from the observed rate of pressure increase in an initially evacuated volume on the other side of the specimen. Permeability constants for hydrogen, deuterium, and tritium were measured for Mylar, Teflon, Kapton, Saran, Buna-N, and latex rubber. Results were compared with literature values for hydrogen and deuterium where available and showed excellent agreement

  20. Organic fluid permeation through fluoropolymer membranes

    Nemser, Stuart M.; Kosaraju, Praveen; Bowser, John

    2015-07-14

    Separation of the components of liquid mixtures is achieved by contacting a liquid mixture with a nonporous membrane having a fluoropolymer selectively permeable layer and imposing a pressure gradient across the membrane from feed side to permeate side. Unusually high transmembrane flux is obtained when the membrane is subjected to one or more process conditions prior to separation. These include (a) leaving some residual amount of membrane casting solvent in the membrane, and (b) contacting the membrane with a component of the mixture to be separated for a duration effective to saturate the membrane with the component.

  1. Bulk oil clauses

    Gough, N.

    1993-01-01

    The Institute Bulk Oil Clauses produced by the London market and the American SP-13c Clauses are examined in detail in this article. The duration and perils covered are discussed, and exclusions, adjustment clause 15 of the Institute Bulk Oil Clauses, Institute War Clauses (Cargo), and Institute Strikes Clauses (Bulk Oil) are outlined. (UK)

  2. Tritium permeation losses in HYLIFE-II heat exchanger tubes

    Longhurst, G.R.; Dolan, T.J.

    1990-01-01

    Tritium permeation through the intermediate heat exchanger of the HYLIFE-II inertial fusion design concept is evaluated for routine operating conditions. The permeation process is modelled using the Lewis analogy combined with surface recombination. It is demonstrated that at very low driving potentials, permeation becomes proportional to the first power of the driving potential. The model predicts that under anticipated conditions the primary cooling loop will pass about 6% of the tritium entering it to the intermediate coolant. Possible approached to reducing tritium permeation are explored. Permeation is limited by turbulent diffusion transport through the molten salt. Hence, surface barriers with impendance factors typical of present technology can do very little to reduce permeation. Low Flibe viscosity is desirable. An efficient tritium removal system operating on the Flibe before it gets to the intermediate heat exchanger is required. Needs for further research are highlighted. 9 refs., 2 figs., 1 tab

  3. Plasma spray formed near-net-shape MoSi2-Si3N4 bulk nanocomposites-structure property evaluation

    Hong, S.J.; Viswanathan, V.; Rea, K.; Patil, S.; Deshpande, S.; Georgieva, P.; McKechnie, T.; Seal, S.

    2005-01-01

    This article, for the first time, presents the challenges toward the successful consolidation of near-net-shape bulk MoSi 2 -Si 3 N 4 -SiC nanocomposite using plasma spray forming. A detailed characterization of the spray formed bulk nanocomponent has been performed using optical microscopy (OM), scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), and Vickers hardness testing. Vickers hardness (900 Hv) and fracture toughness (∼>5 MPa m 1/2 ) of the nanocomposite showed a little deviation from the expected, which might be due to the difference in the particle (Si 3 N 4 ) size and their distribution in the MoSi 2 matrix as a function of component thickness. Relatively higher hardness is attributed to the retention of the nanostructure in the composite. In addition, the as fabricated bulk nanocomposite showed enhanced oxidation resistance

  4. Development of a Contact Permeation Test Fixture and Method

    2013-04-01

    Permeation and Analytical Solutions Team Quality System documentation and the guidance found in the ISO 17025 standard. All permeation and...annular ring (left) and no pressure (right). 2.2.4 Quality Controls Analytical permeation testing was conducted in accordance with ISO 17025 quality...internal standard. This mixture was vortexed for 20–30 s then centrifuged at 15,000 rpm for 5 min in a Micromax microcentrifuge (Thermo IEC ; Needham

  5. In situ measurement of tritium permeation through stainless steel

    Luscher, Walter G.; Senor, David J.; Clayton, Kevin K.; Longhurst, Glen R.

    2013-06-01

    The TMIST-2 irradiation experiment was conducted in the Advanced Test Reactor at Idaho National Laboratory to evaluate tritium permeation through Type 316 stainless steel (316 SS). The interior of a 316 SS seamless tube specimen was exposed to a 4He carrier gas mixed with a specified quantity of tritium (T2) to yield partial pressures of 0.1, 5, and 50 Pa at 292 °C and 330 °C. In situ tritium permeation measurements were made by passing a He-Ne sweep gas over the outer surface of the specimen to carry the permeated tritium to a bubbler column for liquid scintillation counting. Results from in situ permeation measurements were compared with predictions based on an ex-reactor permeation correlation in the literature. In situ permeation data were also used to derive an in-reactor permeation correlation as a function of temperature and pressure over the ranges considered in this study. In addition, the triton recoil contribution to tritium permeation, which results from the transmutation of 3He to T, was also evaluated by introducing a 4He carrier gas mixed with 3He at a partial pressure of 1013 Pa at 330 °C. Less than 3% of the tritium resulting from 3He transmutation contributed to tritium permeation.

  6. Separation of aromatics by vapor permeation through solvent swollen membrane

    Ito, A.; Adachi, K.; Feng, Y. [Niigata University, Niigata (Japan)

    1995-12-20

    A vapor permeation process for aromatics separation from a hydrocarbon mixture was studied by means of the simultaneous permeation of dimethylsulfoxide vapor as an agent for membrane swelling and preferential permeation of aromatics. The separation performance of the process was demonstrated by a polyvinylalcohol membrane for mixed vapors of benzene/cyclohexane, xylene/octane and a model gasoline. The aromatic vapors preferentially permeated from these mixed vapor feeds. The separation factor was over 10. The separation mechanism of the process mainly depends on the relative salability of the vapors between aromatics and other hydrocarbons in dimethylsulfoxide. 14 refs., 9 figs., 1 tab.

  7. Hydrogen permeation resistant layers for liquid metal reactors

    McGuire, J.C.

    1980-03-01

    Reviewing the literature in the tritium diffusion field one can readily see a wide divergence in results for both the response of permeation rate to pressure, and the effect of oxide layers on total permeation rates. The basic mechanism of protective oxide layers is discussed. Two coatings which are less hydrogen permeable than the best naturally occurring oxide are described. The work described is part of an HEDL-ANL cooperative research program on Tritium Permeation in Liquid Metal Cooled Reactors. This includes permeation work on hydrogen, deuterium, and tritium with the hydrogen-deuterium research leading to the developments presented

  8. Temperature dependence of the mechanical properties of melt-processed Dy-Ba-Cu-O bulk superconductors evaluated by three point bending tests

    Katagiri, K; Nyilas, A; Sato, T; Hatakeyama, Y; Hokari, T; Teshima, H; Iwamoto, A; Mito, T

    2006-01-01

    Dy-Ba-Cu-O bulk superconductor has an excellent capability of trapping magnetic flux and lower heat conductivity at cryogenic temperatures as compared with Y-Ba-Cu-O bulk superconductor. The Young's modulus and the bending strength in the range from room temperature to 7 K were measured by the three-point bending tests using specimens cut from a melt-processed Dy-Ba-Cu-O bulk superconductor. They were tested in a helium gas flow type cryostat at Forschungszentrum Karlsruhe and in a liquid nitrogen bath at Iwate University. The Young's modulus was calculated by either the slope of stress-strain curve or that of the load-deflection curve of the specimen. Although the bending strength measured in the two institutes coincided well, there was a significant discrepancy in the Young's modulus. The Young's modulus and bending strength increased with decrease of temperature down to 7 K. The amount of increase in the Young's modulus and the bending strength were about 32% and 36% of those at room temperature, respectively. The scatter of data for each run was significant and did not depend on temperature. The temperature dependence of the Young's modulus coincided with that in Y-Ba-Cu-O obtained by ultrasonic velocity. The temperature dependence of the Young's modulus and the bending strength was discussed from the view point of interatomic distance of the bulk crystal

  9. Water Vapor Permeation of Metal Oxide/Polymer Coated Plastic Films

    Numata, Yukihiro; Oya, Toshiyuki; Kuwahara, Mitsuru; Ito, Katsuya

    Barrier performance to water vapor permeation of ceramic coated layers deposited on flexible polymer films is of great interest to food packaging, medical device packaging and flat panel display industries. In this study, a new type film in which a ceramic layer is deposited on a polymer coated film was proposed for lower water vapor permeation. It is important how to control interfacial properties between each layer and film for good barrier performance. Several kinds of polymer coated materials were prepared for changing surface free energy of the films before and after depositing the ceramic layer. The ceramic layer, which is composed of mixed material of SiO2 and Al2O3, was adopted under the same conditions. The following results were obtained; 1) Water vapor permeation is not related to the surface energy of polymer coated films, 2) After depositing the ceramic layer, however, a strong correlation is observed between the water vapor permeation and surface free energy. 3) The phenomenon is considered that the polarity of the polymer layers plays a key role in changing the structure of ceramic coated layers.

  10. In situ measurement of tritium permeation through stainless steel

    Luscher, Walter G., E-mail: walter.luscher@pnnl.gov [Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA 99352 (United States); Senor, David J., E-mail: david.senor@pnnl.gov [Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA 99352 (United States); Clayton, Kevin K., E-mail: kevin.clayton@inl.gov [Idaho National Laboratory, 2525 Fremont Ave., Idaho Falls, ID 83415 (United States); Longhurst, Glen R., E-mail: glenlonghurst@suu.edu [Idaho National Laboratory, 2525 Fremont Ave., Idaho Falls, ID 83415 (United States)

    2013-06-15

    Highlights: ► In situ tritium permeation measurements collected over broad pressure range. ► Test conditions relevant to 316 SS in commercial light water reactors. ► Comparisons between in- and ex-reactor measurements provided. ► Correlation between tritium permeation, temperature, and pressure developed. -- Abstract: The TMIST-2 irradiation experiment was conducted in the Advanced Test Reactor at Idaho National Laboratory to evaluate tritium permeation through Type 316 stainless steel (316 SS). The interior of a 316 SS seamless tube specimen was exposed to a {sup 4}He carrier gas mixed with a specified quantity of tritium (T{sub 2}) to yield partial pressures of 0.1, 5, and 50 Pa at 292 °C and 330 °C. In situ tritium permeation measurements were made by passing a He–Ne sweep gas over the outer surface of the specimen to carry the permeated tritium to a bubbler column for liquid scintillation counting. Results from in situ permeation measurements were compared with predictions based on an ex-reactor permeation correlation in the literature. In situ permeation data were also used to derive an in-reactor permeation correlation as a function of temperature and pressure over the ranges considered in this study. In addition, the triton recoil contribution to tritium permeation, which results from the transmutation of {sup 3}He to T, was also evaluated by introducing a {sup 4}He carrier gas mixed with {sup 3}He at a partial pressure of 1013 Pa at 330 °C. Less than 3% of the tritium resulting from {sup 3}He transmutation contributed to tritium permeation.

  11. Oxygen transport properties of tubular Ce0.9Gd0.1O1.95-La0.6Sr0.4FeO3−d composite asymmetric oxygen permeation membranes supported on magnesium oxide

    Ovtar, Simona; Gurauskis, Jonas; Bjørnetun Haugen, Astri

    2017-01-01

    The oxygen permeation through dense Ce0.9Gd0.1O1.95-La0.6Sr0.4FeO3−d  dual-phase composite asymmetric membranes supported on a porous MgO tube was studied. The membranes were prepared by thermoplastic extrusion, dip coating, co-sintering and infiltration of a catalyst. Oxygen permeation measureme...

  12. Permeation of Light Gases through Hexagonal Ice

    Luis Gales

    2012-09-01

    Full Text Available Gas separation using porous solids have attracted great attention due to their energetic applications. There is an enormous economic and environmental interest in the development of improved technologies for relevant processes, such as H2 production, CO2 separation or O2 and N2 purification from air. New materials are needed for achieving major improvements. Crystalline materials, displaying unidirectional and single-sized pores, preferentially with low pore tortuosity and high pore density, are promising candidates for membrane synthesis. Herein, we study hexagonal ice crystals as an example of this class of materials. By slowly growing ice crystals inside capillary tubes we were able to measure the permeation of several gas species through ice crystals and investigate its relation with both the size of the guest molecules and temperature of the crystal.

  13. Electrical insulator assembly with oxygen permeation barrier

    Van Der Beck, Roland R.; Bond, James A.

    1994-01-01

    A high-voltage electrical insulator (21) for electrically insulating a thermoelectric module (17) in a spacecraft from a niobium-1% zirconium alloy wall (11) of a heat exchanger (13) filled with liquid lithium (16) while providing good thermal conductivity between the heat exchanger and the thermoelectric module. The insulator (21) has a single crystal alumina layer (SxAl.sub.2 O.sub.3, sapphire) with a niobium foil layer (32) bonded thereto on the surface of the alumina crystal (26) facing the heat exchanger wall (11), and a molybdenum layer (31) bonded to the niobium layer (32) to act as an oxygen permeation barrier to preclude the oxygen depleting effects of the lithium from causing undesirable niobium-aluminum intermetallic layers near the alumina-niobium interface.

  14. Tritium permeation model for plasma facing components

    Longhurst, G. R.

    1992-12-01

    This report documents the development of a simplified one-dimensional tritium permeation and retention model. The model makes use of the same physical mechanisms as more sophisticated, time-transient codes such as implantation, recombination, diffusion, trapping and thermal gradient effects. It takes advantage of a number of simplifications and approximations to solve the steady-state problem and then provides interpolating functions to make estimates of intermediate states based on the steady-state solution. The model is developed for solution using commercial spread-sheet software such as Lotus 123. Comparison calculations are provided with the verified and validated TMAP4 transient code with good agreement. Results of calculations for the ITER CDA diverter are also included.

  15. Tritium permeation model for plasma facing components

    Longhurst, G.R.

    1992-12-01

    This report documents the development of a simplified one-dimensional tritium permeation and retention model. The model makes use of the same physical mechanisms as more sophisticated, time-transient codes such as implantation, recombination, diffusion, trapping and thermal gradient effects. It takes advantage of a number of simplifications and approximations to solve the steady-state problem and then provides interpolating functions to make estimates of intermediate states based on the steady-state solution. The model is developed for solution using commercial spread-sheet software such as Lotus 123. Comparison calculations are provided with the verified and validated TMAP4 transient code with good agreement. Results of calculations for the ITER CDA diverter are also included

  16. Experimental heat capacities, excess entropies, and magnetic properties of bulk and nano Fe3O4-Co3O4 and Fe3O4-Mn3O4 spinel solid solutions

    Schliesser, Jacob M.; Huang, Baiyu; Sahu, Sulata K.; Asplund, Megan; Navrotsky, Alexandra; Woodfield, Brian F.

    2018-03-01

    We have measured the heat capacities of several well-characterized bulk and nanophase Fe3O4-Co3O4 and Fe3O4-Mn3O4 spinel solid solution samples from which magnetic properties of transitions and third-law entropies have been determined. The magnetic transitions show several features common to effects of particle and magnetic domain sizes. From the standard molar entropies, excess entropies of mixing have been generated for these solid solutions and compared with configurational entropies determined previously by assuming appropriate cation and valence distributions. The vibrational and magnetic excess entropies for bulk materials are comparable in magnitude to the respective configurational entropies indicating that excess entropies of mixing must be included when analyzing entropies of mixing. The excess entropies for nanophase materials are even larger than the configurational entropies. Changes in valence, cation distribution, bonding and microstructure between the mixing ions are the likely sources of the positive excess entropies of mixing.

  17. Permeation of Telone EC through protective gloves.

    Zainal, Hanaa; Que Hee, Shane S

    2005-09-30

    Telone is a potent fumigant that is based on the chlorinated unsaturated hydrocarbon, 1,3-dichloropropene (1,3-DCP). It is often applied without dilution and so poses severe inhalation and air pollution threats. Urinary metabolites of 1,3-DCP have been detected after Telone skin exposure, so that preventing dermal exposure is also important. The objective of the study was to assess if nitrile and multi-layer ("laminated") gloves provide adequate protection against Telone EC formulation. To accomplish this, disposable (Safeskin) and chemically resistant (Sol-Vex) nitrile and laminated (Barrier mark and Silver Shield) glove materials were challenged by Telone EC with hexane liquid collection in an ASTM-type I-PTC-600 permeation cell. Analyses of cis- and trans-1,3-DCP in the collection fluid at specified times were performed on a moderately polar capillary column by gas chromatography-electron capture detection. Telone EC caused microholes in both nitrile materials, though the chemically protective material was degraded slower than the disposable nitrile. The laminated gloves offered limited protection. Silver Shield protected best because 1.5-2.3 mg 1,3-DCP permeated by 8 h relative to 2.5-7.6 mg for Barrier, implying about 2.5 times more protection for 8 h. Even for Silver Shield, the extent of protection was inadequate as illustrated by a risk assessment of the skin exposure situation. The normalized breakthrough times for both types of laminated gloves varied between 27 and 60 min. It is recommended that Viton gloves still be worn for protection.

  18. A study on reverse osmosis permeating treatment for yarn dyeing ...

    This paper presents a fuzzy linear regression model for estimation of reverse osmosis permeating parameters conditions. The proposed model can effectively take on non-crisp, fuzzy and crisp data. This study model used for estimation of reverse osmosis permeating parameters data from Tirupur examines the variables that ...

  19. Effect of Nutrient Formulations on Permeation of Proteins and Lipids ...

    Purpose: To investigate the effect of nutrient formulations on the permeation of proteins and lipids through porcine intestine in vitro. Method: In vitro permeation studies of proteins and lipids of two peptide-based formulations, composed of various compounds and sources of hydrolyzed protein was carried out, and compared ...

  20. An unheated permeation device for calibrating atmospheric VOC measurements

    J. Brito

    2011-10-01

    Full Text Available The development of an unpowered permeation device for continuous calibration of in-situ instruments measuring atmospheric volatile organic compounds (VOCs is described. Being lightweight and compact, and containing only negligible amounts of chemicals, the device is especially suited for field use such as on board aircraft. Its speciality is to maintain the permeation process in thermal equilibrium, so that the instantaneous permeation rate can be ascribed to a simple temperature measurement. This equilibrium state is maintained by a combination of three features: (i a thin PTFE membrane as permeation medium which guarantees short stabilization times, (ii a water bath as heat buffer, and (iii a vacuum-panel based insulation, in which features (ii and (iii minimize temperature drifts to ~30 mK h−1 per Kelvin temperature difference to the environment. The respective uncertainty of the permeation rate due to thermal non-equilibrium is kept below 1%. An extensive theory part details the major permeation processes of gases through porous polymers, being Fick's diffusion, Knudsen flow, and viscous flow. Both the measured stabilization time and the measured temperature dependence of the permeation rate independently indicate that the permeation can be described by a viscous flow model, where diffusion of the gas molecules in large pores (having a diameter of >0.05 μm dominates.

  1. Implantation driven permeation behavior of deuterium through pure tungsten

    Nakamura, Hirofumi E-mail: nakamura@tpl.tokai.jaeri.go.jp; Hayashi, Takumi; Nishi, Masataka; Arita, Makoto; Okuno, Kenji

    2001-09-01

    Implantation driven permeation behavior of deuterium through pure tungsten has been investigated to estimate the amount of tritium permeation through its barrier in a thermo-nuclear fusion device. The permeation experiments were performed on pure tungsten foil of 25 {mu}m thickness under conditions of incident flux of 1.9x10{sup 18}-1.1x10{sup 19} D{sup +}/m{sup 2}s, incident ion energy of 200-2000 eV, and specimen temperature of 512-660 K. As a result of this steady-state permeation experiment, the rate-determining process of deuterium permeation was found to be controlled by diffusion at both implanted and permeated sides. On the other hand, transient permeation was strongly affected by trap effect in the specimen. Simulation analysis using TMAP code on transient permeation behavior indicates the existence of a trap site with a trap energy of nearly 1eV and with a trap density of over several ten's ppm in tungsten.

  2. Implantation driven permeation behavior of deuterium through pure tungsten

    Nakamura, Hirofumi; Hayashi, Takumi; Nishi, Masataka; Arita, Makoto; Okuno, Kenji

    2001-01-01

    Implantation driven permeation behavior of deuterium through pure tungsten has been investigated to estimate the amount of tritium permeation through its barrier in a thermo-nuclear fusion device. The permeation experiments were performed on pure tungsten foil of 25 μm thickness under conditions of incident flux of 1.9x10 18 -1.1x10 19 D + /m 2 s, incident ion energy of 200-2000 eV, and specimen temperature of 512-660 K. As a result of this steady-state permeation experiment, the rate-determining process of deuterium permeation was found to be controlled by diffusion at both implanted and permeated sides. On the other hand, transient permeation was strongly affected by trap effect in the specimen. Simulation analysis using TMAP code on transient permeation behavior indicates the existence of a trap site with a trap energy of nearly 1eV and with a trap density of over several ten's ppm in tungsten

  3. Synthesis and mechanical properties of bulk Al{sub 76}Ni{sub 8}Ti{sub 8}Zr{sub 4}Y{sub 4} alloy fabricated by consolidation of mechanically alloyed amorphous powders

    Wang, Xinfu; Wang, Kun; Li, Zhendong; Wang, Xingfu; Wang, Dan; Han, Fusheng, E-mail: fshan@issp.ac.cn

    2015-05-25

    Graphical abstract: Different regions indentation morphologies under 50 g load consolidated at 723 K (left), nanohardness of the Al{sub 76}Ni{sub 8}Ti{sub 8}Zr{sub 4}Y{sub 4} alloy as a function consolidation temperature (right). It can be seen from the above figures that the consolidated sample presents white regions, and the microhardness in the white regions is a little lower than the matrix, which could be caused by the difference of the chemical composition and chemical bonding forces between them. Interestingly, the cracks were formed around the indentation periphery in the white regions, which are not shown in the matrix. The nanohardness of the bulk composites increased from 11.16 to 13.27 GPa with the consolidation temperature increasing, mechanical softening was also found in the present alloys. - Highlights: • Bulk amorphous–nanocrystalline Al-based alloys were prepared by HPS process. • The Vickers microhardness of bulk samples is in the range of 945–1177HV0.1. • The nanohardness agrees well with the Vickers hardness testing results. - Abstract: Mechanically alloyed amorphous Al{sub 76}Ni{sub 8}Ti{sub 8}Zr{sub 4}Y{sub 4} (at.%) alloy powder was consolidated by high-pressure sintering process. The influence of the consolidation temperature on the structure and mechanical properties of the consolidated bulk alloys was examined by X-ray diffraction (XRD), Optical microscopy (OM), Scanning electron microscopy (SEM), Vickers Hardness Tester and Nano Indenter. Structural investigations of the bulk materials revealed that most of the amorphous structure was retained after consolidation at 623 K, however, compaction at 723 K and 823 K caused crystallization of the amorphous phase with the appearance of white regions. The results also indicate that application of high pressure affected the crystallization products of the present alloy. Micro mechanical analysis showed that the microhardness of the bulk composites increased from 945HV{sub 0.1} to 1177HV

  4. Accelerating universes driven by bulk particles

    Brito, F.A.; Cruz, F.F.; Oliveira, J.F.N.

    2005-01-01

    We consider our universe as a 3d domain wall embedded in a 5d dimensional Minkowski space-time. We address the problem of inflation and late time acceleration driven by bulk particles colliding with the 3d domain wall. The expansion of our universe is mainly related to these bulk particles. Since our universe tends to be permeated by a large number of isolated structures, as temperature diminishes with the expansion, we model our universe with a 3d domain wall with increasing internal structures. These structures could be unstable 2d domain walls evolving to fermi-balls which are candidates to cold dark matter. The momentum transfer of bulk particles colliding with the 3d domain wall is related to the reflection coefficient. We show a nontrivial dependence of the reflection coefficient with the number of internal dark matter structures inside the 3d domain wall. As the population of such structures increases the velocity of the domain wall expansion also increases. The expansion is exponential at early times and polynomial at late times. We connect this picture with string/M-theory by considering BPS 3d domain walls with structures which can appear through the bosonic sector of a five-dimensional supergravity theory

  5. Development of Fe-AI CVD coatings as tritium permeation barrier

    Chabrol, C.; Schuster, F.; Le Marois, G.; Serra, E.

    1998-01-01

    A specific method of pack-cementation has been developed in order to perform a CVD deposition of Fe-Al alloys on a martensitic steel at a temperature which respects its mechanical properties ( 2 Al 5 intermetallic phases thanks to a low pressure deposition and using a special cement containing Fe and Al. These coatings coated with an Al 2 O 3 top layer drastically reduce the permeation rate of deuterium with regards to the uncoated substrate. (authors)

  6. Purification Simulation With Vapor Permeation and Distillation-Adsorption In Bioethanol Plant

    Misri Gozan; Mia Sari Setiawan; Kenny Lischer

    2017-01-01

    High purity of Bioethanol is required in biofuel mixing with gasoline (EXX). In bioethanol production line, the azeotropic property of ethanol-water becomes the barrier for purification process. This study examined two bioethanol separation processes by support of simulation tools, Superpro Designer 9.0 software. Ethanol purity and a low costeconomical process were the major considerations. Purification method of vapor permeation membrane technology was compared with distillation-adsorption m...

  7. New experimental set-up and procedure for analyzing the dynamics of permeation of H2(g) across Pd-based metallic membranes

    Decaux, C.; Millet, P.; Decaux, C.

    2006-01-01

    Hydrogen permeation through metallic membranes is an industrial process used for purification purposes. Palladium-based alloys are generally used as permeation materials at operating temperatures above the critical value so that the metal-H system remains monophasic and that diffusion proceeds at sufficient rate. In state of the art systems, metallic membranes with typical thickness of a few tens of microns are used and rate limitation are generally attributed to atomic H transport by diffusion. Because of cost considerations, it is necessary to reduce the thickness of these membranes. In the micron thick range, surface contributions are expected to become rate determining, or at least to play an increasing role. Further, when the membrane is used on the exit side of a gas reformer to directly extract hydrogen, corrosion problems are expected to occur on the upstream side of the membrane. For all these reasons, there is a need to separately measure surface and bulk (diffusion) rate contributions to the overall permeation flux. A new experimental equipment has been specifically designed for this purpose. This setup can be operated in two different modes: for sorption or permeation experiments. In a typical sorption experiment, the metallic membrane is disposed in the reaction chamber and hydrogen is allowed to react from both side of the surface. This procedure allows the separate measurement of surface absorption and desorption resistances associated with the chemisorption step. In a typical permeation experiment, the membrane is mounted between two volume chambers, a pressurized hydrogen source reservoir and an empty sink reservoir. Initially, a difference of pressure is set between the two reservoirs. When the valve of the source tank is opened, H 2 (g) flows to the membrane and permeation proceeds until pressure reaches an equilibrium value. In both experimental configurations, gas pressure transients are synchronously sampled all along the experiment

  8. Permeation mechanisms of pulsed microwave plasma deposited silicon oxide films for food packaging applications

    Deilmann, Michael; Grabowski, Mirko; Theiss, Sebastian; Bibinov, Nikita; Awakowicz, Peter

    2008-01-01

    Silicon oxide barrier layers are deposited on polyethylene terephthalate as permeation barriers for food packaging applications by means of a low pressure microwave plasma. Hexamethyldisiloxane (HMDSO) and oxygen are used as process gases to deposit SiO x coatings via pulsed low pressure plasmas. The layer composition of the coating is investigated by Fourier transform infrared spectroscopy and energy dispersive x-ray spectroscopy to show correlations with barrier properties of the films. The oxygen permeation barrier is determined by the carrier gas method using an electrochemical detector. The transition from low to high barrier films is mapped by the transition from organic SiO x C y H z layers to quartz-like SiO 1.7 films containing silanol bound hydrogen. A residual permeation as low as J = 1 ± 0.3 cm 3 m -2 day -1 bar -1 is achieved, which is a good value for food packaging applications. Additionally, the activation energy E p of oxygen permeation is analysed and a strong increase from E p = 31.5 kJ mol -1 for SiO x C y H z -like coatings to E p = 53.7 kJ mol -1 for SiO 1.7 films is observed by increasing the oxygen dilution of HMDSO:O 2 plasma. The reason for the residual permeation of high barrier films is discussed and coating defects are visualized by capacitively coupled atomic oxygen plasma etching of coated substrates. A defect density of 3000 mm -2 is revealed

  9. Evidence of a Transition Layer between the Free Surface and the Bulk

    Ogieglo, Wojciech

    2018-02-21

    The free surface, a very thin layer at the interface between polymer and air, is considered the main source of the perturbations in the properties of ultrathin polymer films, i.e., nanoconfinement effects. The structural relaxation of such a layer is decoupled from the molecular dynamics of the bulk. The free surface is, in fact, able to stay liquid even below the temperature where the polymer resides in the glassy state. Importantly, this surface layer is expected to have a very sharp interface with the underlying bulk. Here, by analyzing the penetration of n-hexane into polystyrene films, we report on the existence of a transition region, not observed by previous investigations, extending for 12 nm below the free surface. The presence of such a layer permits reconciling the behavior of interfacial layers with current models and has profound implications on the performance of ultrathin membranes. We show that the expected increase in the flux of the permeating species is actually overruled by nanoconfinement.

  10. Evidence of a Transition Layer between the Free Surface and the Bulk

    Ogieglo, Wojciech; Tempelman, Kristianne; Napolitano, Simone; Benes, Nieck E.

    2018-01-01

    The free surface, a very thin layer at the interface between polymer and air, is considered the main source of the perturbations in the properties of ultrathin polymer films, i.e., nanoconfinement effects. The structural relaxation of such a layer is decoupled from the molecular dynamics of the bulk. The free surface is, in fact, able to stay liquid even below the temperature where the polymer resides in the glassy state. Importantly, this surface layer is expected to have a very sharp interface with the underlying bulk. Here, by analyzing the penetration of n-hexane into polystyrene films, we report on the existence of a transition region, not observed by previous investigations, extending for 12 nm below the free surface. The presence of such a layer permits reconciling the behavior of interfacial layers with current models and has profound implications on the performance of ultrathin membranes. We show that the expected increase in the flux of the permeating species is actually overruled by nanoconfinement.

  11. Evidence of a Transition Layer between the Free Surface and the Bulk.

    Ogieglo, Wojciech; Tempelman, Kristianne; Napolitano, Simone; Benes, Nieck E

    2018-03-15

    The free surface, a very thin layer at the interface between polymer and air, is considered the main source of the perturbations in the properties of ultrathin polymer films, i.e., nanoconfinement effects. The structural relaxation of such a layer is decoupled from the molecular dynamics of the bulk. The free surface is, in fact, able to stay liquid even below the temperature where the polymer resides in the glassy state. Importantly, this surface layer is expected to have a very sharp interface with the underlying bulk. Here, by analyzing the penetration of n-hexane into polystyrene films, we report on the existence of a transition region, not observed by previous investigations, extending for 12 nm below the free surface. The presence of such a layer permits reconciling the behavior of interfacial layers with current models and has profound implications on the performance of ultrathin membranes. We show that the expected increase in the flux of the permeating species is actually overruled by nanoconfinement.

  12. Ion Permeation and Mechanotransduction Mechanisms of Mechanosensitive Piezo Channels.

    Zhao, Qiancheng; Wu, Kun; Geng, Jie; Chi, Shaopeng; Wang, Yanfeng; Zhi, Peng; Zhang, Mingmin; Xiao, Bailong

    2016-03-16

    Piezo proteins have been proposed as the long-sought-after mechanosensitive cation channels in mammals that play critical roles in various mechanotransduction processes. However, the molecular bases that underlie their ion permeation and mechanotransduction have remained functionally undefined. Here we report our finding of the miniature pore-forming module of Piezo1 that resembles the pore architecture of other trimeric channels and encodes the essential pore properties. We further identified specific residues within the pore module that determine unitary conductance, pore blockage and ion selectivity for divalent and monovalent cations and anions. The non-pore-containing region of Piezo1 confers mechanosensitivity to mechano-insensitive trimeric acid-sensing ion channels, demonstrating that Piezo1 channels possess intrinsic mechanotransduction modules separate from their pore modules. In conclusion, this is the first report on the bona fide pore module and mechanotransduction components of Piezo channels, which define their ion-conducting properties and gating by mechanical stimuli, respectively. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Preparation of Silica Nanoparticles Loaded with Nootropics and Their In Vivo Permeation through Blood-Brain Barrier

    Josef Jampilek

    2015-01-01

    Full Text Available The blood-brain barrier prevents the passage of many drugs that target the central nervous system. This paper presents the preparation and characterization of silica-based nanocarriers loaded with piracetam, pentoxifylline, and pyridoxine (drugs from the class of nootropics, which are designed to enhance the permeation of the drugs from the circulatory system through the blood-brain barrier. Their permeation was compared with non-nanoparticle drug substances (bulk materials by means of an in vivo model of rat brain perfusion. The size and morphology of the nanoparticles were characterized by transmission electron microscopy. The content of the drug substances in silica-based nanocarriers was analysed by elemental analysis and UV spectrometry. Microscopic analysis of visualized silica nanocarriers in the perfused brain tissue was performed. The concentration of the drug substances in the tissue was determined by means of UHPLC-DAD/HRMS LTQ Orbitrap XL. It was found that the drug substances in silica-based nanocarriers permeated through the blood brain barrier to the brain tissue, whereas bulk materials were not detected in the brain.

  14. Preparation of silica nanoparticles loaded with nootropics and their in vivo permeation through blood-brain barrier.

    Jampilek, Josef; Zaruba, Kamil; Oravec, Michal; Kunes, Martin; Babula, Petr; Ulbrich, Pavel; Brezaniova, Ingrid; Opatrilova, Radka; Triska, Jan; Suchy, Pavel

    2015-01-01

    The blood-brain barrier prevents the passage of many drugs that target the central nervous system. This paper presents the preparation and characterization of silica-based nanocarriers loaded with piracetam, pentoxifylline, and pyridoxine (drugs from the class of nootropics), which are designed to enhance the permeation of the drugs from the circulatory system through the blood-brain barrier. Their permeation was compared with non-nanoparticle drug substances (bulk materials) by means of an in vivo model of rat brain perfusion. The size and morphology of the nanoparticles were characterized by transmission electron microscopy. The content of the drug substances in silica-based nanocarriers was analysed by elemental analysis and UV spectrometry. Microscopic analysis of visualized silica nanocarriers in the perfused brain tissue was performed. The concentration of the drug substances in the tissue was determined by means of UHPLC-DAD/HRMS LTQ Orbitrap XL. It was found that the drug substances in silica-based nanocarriers permeated through the blood brain barrier to the brain tissue, whereas bulk materials were not detected in the brain.

  15. The influence of irradiation potential on the degree of conversion and mechanical properties of two bulk-fill flowable RBC base materials.

    Finan, Leah; Palin, William M; Moskwa, Natalia; McGinley, Emma Louise; Fleming, Garry J P

    2013-08-01

    To assess the depth of cure claims of two bulk-fill flowable RBC bases (SDR and x-tra base) using Fourier transform infrared (FTIR) spectroscopy, biaxial flexure strength (BFS), and Vickers hardness number (VHN) for specimen depths of 8mm (in 1mm increments). The degree of conversion (DC) was measured by monitoring the peak height (6164cm(-1)) of specimens (11.0±0.1mm diameter, 1.0±0.1mm thickness) during light irradiation for 20s using a quartz tungsten halogen light curing unit at 650±26mW/cm(2). DC was measured up to 120s post irradiation and repeated (n=3) for irradiation depths up to 8mm (in 1mm increments). Further series (n=20) of eight discs were prepared, stacked, light irradiated and numbered from one to eight (distance from the LCU). The specimens were stored at 37±1°C for 24h and BFS tested with the fracture fragments used to determine the VHN for each specimen. X-tra base can be irradiated to 8mm without a change in DC, something the SDR material cannot claim. However, the DC results confirm both bulk-fill flowable RBC bases have a depth of cure in excess of 4mm. One-way ANOVAs of BFS and VHN data showed significant differences between irradiation depths for x-tra base and SDR with increasing irradiation depth (4mm) resulting in significant reductions in mean BFS and VHN. The claims that the bulk-fill flowable RBC bases have a depth of cure in excess of 4mm can be confirmed but the differing chemistry of the resin formulations and filler characteristics contribute to significant differences in DC, BFS and VHN data between the two materials tested. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  16. Effect of shock pressure on the structure and superconducting properties of Y-Ba-Cu-O in explosively fabricated bulk metal-matrix composites

    Murr, L. E.; Niou, C. S.; Pradhan-Advani, M.

    1991-01-01

    While it is now well established that copper-oxide-based power, or virtually any other ceramic superconductor powder, can be consolidated and encapsulated within a metal matrix by explosive consolidation, the erratic superconductivity following fabrication has posed a major problem for bulk applications. The nature of this behavior was found to arise from microstructural damage created in the shock wave front, and the residual degradation in superconductivity was demonstrated to be directly related to the peak shock pressure. The explosively fabricated or shock loaded YBa2Cu3Ox examples exhibit drastically altered rho (or R) - T curves. The deterioration in superconductivity is even more noticeable in the measurement of ac magnetic susceptibility and flux exclusion or shielding fraction which is also reduced in proportion to increasing peak shock pressure. The high frequency surface resistance (in the GHz range) is also correspondingly compromised in explosively fabricated, bulk metal-matrix composites based on YBa2Cu3O7. Transmission electron microscopy (including lattice imaging techniques) is being applied in an effort to elucidate the fundamental (microstructural) nature of the shock-induced degradation of superconductivity and normal state conductivity. One focus of TEM observations has assumed that oxygen displaced from b-chains rather than oxygen-vacancy disorder in the basal plane of oxygen deficient YBa2Cu3Ox may be a prime mechanism. Shock-wave displaced oxygen may also be locked into new positions or interstitial clusters or chemically bound to displaced metal (possibly copper) atoms to form precipitates, or such displacements may cause the equivalent of local lattice cell changes as a result of stoichiometric changes. While the shock-induced suppression of T(sub c) is not desirable in the explosive fabrication of bulk metal-matrix superconductors, it may be turned into an advantage if the atomic-scale distortion can be understood and controlled as local

  17. Preparation of high crystalline nanoparticles of rare-earth based complex pervoskites and comparison of their structural and magnetic properties with bulk counterparts

    Basith, M. A.; Islam, M. A.; Ahmmad, Bashir

    2017-01-01

    of crystalline and amorphous phases. FESEM images demonstrate the formation of nanoparticles with average particle size in the range of 50–100 nm for both ultrasonication and 4 h (h) of ball milling. The bulk materials and nanoparticles synthesized by both ultrasonication and 4 h ball milling exhibit...... of the nanoparticles due to ball milling particularly for milling time exceeding 8 h. This investigation demonstrates the potential of ultrasonication as a simple route to prepare high crystalline rare-earth based manganite nanoparticles with improved control compared to the traditional ball milling technique....

  18. The effect of nano-size ZrO2 powder addition on the microstructure and superconducting properties of single-domain Y-Ba-Cu-O bulk superconductors

    Iida, K; Babu, N H; Reddy, E S; Shi, Y-H; Cardwell, D A

    2005-01-01

    The effect of nano-size ZrO 2 powder addition on the microstructure and superconducting properties of Y-Ba-Cu-O single grain bulk superconductors has been investigated. Significant pushing phenomena of Y 2 BaCuO 5 (Y-211) particles, particularly in the c growth sector, were observed even with a small amount of ZrO 2 added to the precursor powder. An increase in Y-211 particle pushing was observed with increasing ZrO 2 content, leading to an inhomogeneous bulk microstructure. In addition, a growth cycle consisting of a Y-211 free layer-porous narrow layer-Y-211 high concentration layer was observed for samples prepared with 0.25 wt% ZrO 2 in both the a and c growth sectors. The extent of the growth of single grain Y-Ba-Cu-O (YBCO) decreased with increasing ZrO 2 content due to increased pushing of Y-211 particles towards molten liquid. The superconducting transition temperature, T c , of the ZrO 2 containing YBCO samples was sharp but depressed slightly (by up to 1 K) compared with an undoped YBCO grain, indicating a relative insensitivity of T c to ZrO 2 content. Finally, the sensitivity of critical current density, J c , to applied magnetic field in large grain bulk YBCO containing ZrO 2 was observed to depend critically on position due to the inhomogeneous sample microstructure

  19. Bulk amorphous alloys: Preparation and properties of (Mg0.98Al0.02)x(Cu0.75Y0.25)100

    Eldrup, Morten Mostgaard; Pedersen, Allan Schrøder; Ohnuma, M.

    2000-01-01

    New bulk amorphous quaternary alloys of the composition (Mg1-xAlx)(60)Cu30Y10 (x = 0 - 0.17) were recently reported by the authors and preliminary results of the influence of Al content on the ability to form a bulk amorphous phase were presented. In the present note we extend this work to look...... for the influence of the Mg-Al content on the glass forming ability by studying a range of compositions, (Mg0.98Al0.02)(x)(Cu0.75Y0.25)(100-x) for x = 60 - 80 at.%. As previously, the alloys were prepared by a relatively simple technique, i.e. rapid cooling of the melt in a wedge-shaped copper mould. This method...... provides a range of cooling rates within a single ingot during the solidification that link the slowly and rapidly cooled microstructure for each alloy composition. Hence, the maximum thickness of the amorphous part of the cast material will be a measure of the glass forming ability (GFA) of the particular...

  20. Naphtho[2,1-b:3,4-b']dithiophene-based bulk heterojunction solar cells: how molecular structure influences nanoscale morphology and photovoltaic properties.

    Kim, Yu Jin; Cheon, Ye Rim; Back, Jang Yeol; Kim, Yun-Hi; Chung, Dae Sung; Park, Chan Eon

    2014-11-10

    Organic bulk heterojunction photovoltaic devices based on a series of three naphtho[2,1-b:3,4-b']dithiophene (NDT) derivatives blended with phenyl-C71-butyric acid methyl ester were studied. These three derivatives, which have NDT units with various thiophene-chain lengths, were employed as the donor polymers. The influence of their molecular structures on the correlation between their solar-cell performances and their degree of crystallization was assessed. The grazing-incidence angle X-ray diffraction and atomic force microscopy results showed that the three derivatives exhibit three distinct nanoscale morphologies. We correlated these morphologies with the device physics by determining the J-V characteristics and the hole and electron mobilities of the devices. On the basis of our results, we propose new rules for the design of future generations of NDT-based polymers for use in bulk heterojunction solar cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Development of tritium permeation barriers on Al base in Europe

    Benamati, G.; Chabrol, C.; Perujo, A.; Rigal, E.; Glasbrenner, H.

    The development of the water cooled lithium lead (WCLL) DEMO fusion reactor requires the production of a material capable of acting as a tritium permeation barrier (TPB). In the DEMO blanket reactor permeation barriers on the structural material are required to reduce the tritium permeation from the Pb-17Li or the plasma into the cooling water to acceptable levels (HIP) technology and spray (this one developed also for repair) deposition techniques. The final goal is to select a reference technique to be used in the blanket of the DEMO reactor and in the ITER test module fabrication. The activities performed in four European laboratories are summarised here.

  2. Reemission and permeation of deuterium implanted into metals

    Tanabe, T.; Furuyama, Y.; Imoto, S.

    1984-01-01

    Focusing on the marked depression of deuterium permeation rate during the deuteron bombardment, implantation experiments coupled with gaseous permeation experiments are performed on pure Ni and Ni with evaporated MnO. It is concluded that the reemission of implanted deuterium is initially depressed, but it soon becomes enhanced with increase of fluence leading to a rapid decrease of permeation rate at the intermediate temperatures 600-1000 K, which is attributed to the formation of short diffusion paths from the projected range to the front surface. (orig.)

  3. Permeation enhancer strategies in transdermal drug delivery.

    Marwah, Harneet; Garg, Tarun; Goyal, Amit K; Rath, Goutam

    2016-01-01

    Today, ∼74% of drugs are taken orally and are not found to be as effective as desired. To improve such characteristics, transdermal drug delivery was brought to existence. This delivery system is capable of transporting the drug or macromolecules painlessly through skin into the blood circulation at fixed rate. Topical administration of therapeutic agents offers many advantages over conventional oral and invasive techniques of drug delivery. Several important advantages of transdermal drug delivery are prevention from hepatic first pass metabolism, enhancement of therapeutic efficiency and maintenance of steady plasma level of the drug. Human skin surface, as a site of drug application for both local and systemic effects, is the most eligible candidate available. New controlled transdermal drug delivery systems (TDDS) technologies (electrically-based, structure-based and velocity-based) have been developed and commercialized for the transdermal delivery of troublesome drugs. This review article covers most of the new active transport technologies involved in enhancing the transdermal permeation via effective drug delivery system.

  4. Permeation rates for RTF metal hydride vessels

    Klein, J.E.

    1992-01-01

    Contamination rates have been estimated for the RTF nitrogen heating and cooling system (NH and CS) due to tritium permeation through the walls of metal hydride vessels. Tritium contamination of the NH and CS will be seen shortly after start-up of the RTF with the majority of it coming from the TCAP units. Contamination rates of the NH and CS are estimated to exceed 400 Ci/year after three years of operation and will elevate tritium concentrations in the NH and CS above 6 x 10 -3 μCi/cc. To reduce tritium activity in the NH and CS, a stripper or ''getter'' bed may need to be installed in the NH and CS. Increasing the purge rate of nitrogen from the NH and CS is shown to be an impractical method for reducing tritium activity due to the high purge rates required. Stripping of the NH and CS nitrogen in the glove box stripper system will give a temporary lowering of tritium activity in the NH and CS, but tritium activity will return to its previous level in approximately two weeks

  5. Permeation of sumatriptan succinate across human skin using multiple types of self-dissolving microneedle arrays fabricated from sodium hyaluronate.

    Wu, Dan; Katsumi, Hidemasa; Quan, Ying-Shu; Kamiyama, Fumio; Kusamori, Kosuke; Sakane, Toshiyasu; Yamamoto, Akira

    2016-09-01

    Available formulations of sumatriptan succinate (SS) have low bioavailability or are associated with site reactions. We developed various types of self-dissolving microneedle arrays (MNs) fabricated from sodium hyaluronate as a new delivery system for SS and evaluated their skin permeation and irritation in terms of clinical application. In vitro permeation studies with human skin, physicochemical properties (needle length, thickness and density), and penetration enhancers (glycerin, sodium dodecyl sulfate and lauric acid diethanolamide) were investigated. SS-loaded high-density MNs of 800 µm in length were the optimal formulation and met clinical therapeutic requirements. Penetration enhancers did not significantly affect permeation of SS from MNs. Optical coherence tomography images demonstrated that SS-loaded high-density MNs (800 µm) uniformly created drug permeation pathways for the delivery of SS into the skin. SS-loaded high-density MNs induced moderate primary skin irritations in rats, but the skin recovered within 72 h of removal of the MNs. These findings suggest that high-density MNs of 800 µm in length are an effective and promising formulation for transdermal delivery of SS. To our knowledge, this is the first report of SS permeation across human skin using self-dissolving MNs.

  6. Large area bulk superconductors

    Miller, Dean J.; Field, Michael B.

    2002-01-01

    A bulk superconductor having a thickness of not less than about 100 microns is carried by a polycrystalline textured substrate having misorientation angles at the surface thereof not greater than about 15.degree.; the bulk superconductor may have a thickness of not less than about 100 microns and a surface area of not less than about 50 cm.sup.2. The textured substrate may have a thickness not less than about 10 microns and misorientation angles at the surface thereof not greater than about 15.degree.. Also disclosed is a process of manufacturing the bulk superconductor and the polycrystalline biaxially textured substrate material.

  7. Characterization of silver/polystyrene nanocomposites prepared by in situ bulk radical polymerization

    Vukoje, Ivana D., E-mail: ivanav@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia); Vodnik, Vesna V., E-mail: vodves@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia); Džunuzović, Jasna V., E-mail: jasnav2002@googlemail.com [Institute of Chemistry, Technology and Metallurgy (ICTM)-Center of Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade (Serbia); Džunuzović, Enis S., E-mail: edzunuzovic@tmf.bg.ac.rs [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11120 Belgrade (Serbia); Marinović-Cincović, Milena T., E-mail: milena@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia); Jeremić, Katarina, E-mail: kjeremic@tmf.bg.ac.rs [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11120 Belgrade (Serbia); Nedeljković, Jovan M., E-mail: jovned@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia)

    2014-01-01

    Graphical abstract: - Highlights: • Synthesis and characterization of polystyrene nanocomposites based on Ag nanoparticles. • The glass transition temperature decreased in nanocomposites with respect to the pure polymer. • Resistance of the polymer to thermal degradation enhanced with Ag nanoparticles content. - Abstract: Nanocomposites (NCs) with different content of silver nanoparticles (Ag NPs) embeded in polystyrene (PS) matrix were prepared by in situ bulk radical polymerization. The nearly monodisperse Ag NPs protected with oleylamine were synthesized via organic solvo-thermal method and further used as a filler. The as-prepared spherical Ag NPs with diameter of 7.0 ± 1.5 nm were well dispersed in the PS matrix. The structural properties of the resulting Ag/PS NCs were characterized by transmission electron microscope (TEM) and Fourier transform infrared (FTIR) spectroscopy, while optical properties were characterized using optical absorption measurements. The gel permeation chromatography (GPC) measurements showed that the presence of Ag NPs stabilized with oleylamine has no influence on the molecular weight and polydispersity of the PS matrix. The influence of silver content on the thermal properties of Ag/PS NCs was investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results indicated that resistance of PS to thermal degradation was improved upon incorporation of Ag NPs. The Ag/PS NCs have lower glass transition temperatures than neat PS because loosely packed oleylamine molecules at the interface caused the increase of free volume and chain segments mobility near the surface of Ag NPs.

  8. Hydrogen permeation through steel coated with erbium oxide by sol-gel method

    Yao Zhenyu; Suzuki, Akihiro; Levchuk, Denis; Chikada, Takumi; Tanaka, Teruya; Muroga, Takeo; Terai, Takayuki

    2009-01-01

    Er 2 O 3 coating is formed on austenitic stainless steel 316ss by sol-gel method. The results showed good crystallization of coating by baking in high purity flowing-argon at 973 K, and indicated that a little oxygen in baking atmosphere is necessary to crystallization of coating. The best baking temperature could be thought as 973 K, to get good crystallization of coating and avoid strong oxidation of steel substrate. The deuterium permeation test was performed for coated and bare 316ss, to evaluate the property of Er 2 O 3 sol-gel coating as a potential tritium permeation barrier. In this study, the deuterium permeability of coated 316ss is about 1-2 orders of magnitude lower than that of bare 316ss, and is about 2-3 orders of magnitude than the referred data of bare Eurofer97 and F82H martensitic steel.

  9. Electro-Conductive Membranes for Permeation Enhancement and Fouling Mitigation: A Short Review.

    Formoso, Patrizia; Pantuso, Elvira; De Filpo, Giovanni; Nicoletta, Fiore Pasquale

    2017-07-28

    The research on electro-conductive membranes has expanded in recent years. These membranes have strong prospective as key components in next generation water treatment plants because they are engineered in order to enhance their performance in terms of separation, flux, fouling potential, and permselectivity. The present review summarizes recent developments in the preparation of electro-conductive membranes and the mechanisms of their response to external electric voltages in order to obtain an improvement in permeation and mitigation in the fouling growth. In particular, this paper deals with the properties of electro-conductive polymers and the preparation of electro-conductive polymer membranes with a focus on responsive membranes based on polyaniline, polypyrrole and carbon nanotubes. Then, some examples of electro-conductive membranes for permeation enhancement and fouling mitigation by electrostatic repulsion, hydrogen peroxide generation and electrochemical oxidation will be presented.

  10. Electro-Conductive Membranes for Permeation Enhancement and Fouling Mitigation: A Short Review

    Patrizia Formoso

    2017-07-01

    Full Text Available The research on electro-conductive membranes has expanded in recent years. These membranes have strong prospective as key components in next generation water treatment plants because they are engineered in order to enhance their performance in terms of separation, flux, fouling potential, and permselectivity. The present review summarizes recent developments in the preparation of electro-conductive membranes and the mechanisms of their response to external electric voltages in order to obtain an improvement in permeation and mitigation in the fouling growth. In particular, this paper deals with the properties of electro-conductive polymers and the preparation of electro-conductive polymer membranes with a focus on responsive membranes based on polyaniline, polypyrrole and carbon nanotubes. Then, some examples of electro-conductive membranes for permeation enhancement and fouling mitigation by electrostatic repulsion, hydrogen peroxide generation and electrochemical oxidation will be presented.

  11. Contaminant Permeation in the Ionomer-Membrane Water Processor (IWP) System

    Kelsey, Laura K.; Finger, Barry W.; Pasadilla, Patrick; Perry, Jay

    2016-01-01

    The Ionomer-membrane Water Processor (IWP) is a patented membrane-distillation based urine brine water recovery system. The unique properties of the IWP membrane pair limit contaminant permeation from the brine to the recovered water and purge gas. A paper study was conducted to predict volatile trace contaminant permeation in the IWP system. Testing of a large-scale IWP Engineering Development Unit (EDU) with urine brine pretreated with the International Space Station (ISS) pretreatment formulation was then conducted to collect air and water samples for quality analysis. Distillate water quality and purge air GC-MS results are presented and compared to predictions, along with implications for the IWP brine processing system.

  12. Investigation of aluminised steel as a barrier to tritium using accelerator-based and hydrogen permeation techniques

    Sokhi, R S; Forcey, K S; Ross, D K; Earwaker, L G [Birmingham Univ. (UK). School of Physics and Space Research

    1989-04-01

    Aluminised steel has been proposed as a barrier to tritium permeation in fusion reactors. The properties of these materials as tritium barriers have been studied using accelerator-based techniques and hydrogen permeation methods. The aluminide layers has been characterised by Rutherford backscattering spectroscopy (RBS) and nuclear reaction analysis (NRA) techniques using the 3 MV Dynamitron accelerator based at the School of Physics and Space Research Radiation Centre. The effectiveness of the aluminide layer as a tritium barrier has been measured directly by a conventional permeation apparatus over a range of temperatures. The effect of high temperatures on the structure of the aluminide layer has been examined. Any correlation between the composition of the layer and its effectiveness as a tritium barrier is also discussed. (orig.).

  13. Preparation and properties of Fe{sub 80−x}Ni{sub x}P{sub 14}B{sub 6} bulk metallic glasses

    Zhang, Ling; Ma, XiuHua [School of Physics Science and Technology, Xinjiang University, Urumqi, Xinjiang 830046 (China); Li, Qiang, E-mail: qli@xju.edu.cn [School of Physics Science and Technology, Xinjiang University, Urumqi, Xinjiang 830046 (China); Zhang, Jijun [School of Physics Science and Technology, Xinjiang University, Urumqi, Xinjiang 830046 (China); Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201 (China); Dong, Yaqiang; Chang, Chuntao [Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201 (China)

    2014-09-01

    Highlights: • Fe{sub 80−x}Ni{sub x}P{sub 14}B{sub 6} (x = 20–50 at.%) BMGs were prepared by fluxing and J-quenching techniques. • The highest GFA is reached at x = 40 and the corresponding critical diameter is up to 2.5 mm. • The present FeNi-based BMGs exhibit very large ε{sub p} and the ε{sub p} of Fe{sub 30}Ni{sub 50}P{sub 14}B{sub 6} BMG is 11.7%. • The present FeNi-based BMGs have much higher corrosion resistance than stainless steel. - Abstract: Bulk Fe{sub 80−x}Ni{sub x}P{sub 14}B{sub 6} (x = 20, 30, 40, 50 at.%) glassy alloy rods with the diameters of 1.0–2.5 mm were synthesized by combining fluxing technique and J-quenching technique. The glassy alloy rods were characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and vibrating sample magnetometer (VSM). It is found that the range of supercooled liquid region (ΔT{sub x}) is 27–32 K. The saturation magnetization of Fe{sub 80−x}Ni{sub x}P{sub 14}B{sub 6} (x = 20, 30, 40, 50 at.%) bulk glassy alloys gradually decreases from 1.13 T to 0.58 T with increasing Ni content from x = 20 to x = 50. More importantly, the present quaternary FeNiPB bulk metallic glasses (BMGs) shows a significant plastic strain, in particular, the plastic strain of Fe{sub 30}Ni{sub 50}P{sub 14}B{sub 6} BMG reaches as high as 11.7%. The corrosion resistance of the present FeNiPB BMGs was studied by weight-loss method, potentiodynamic polarization curves and scanning electron microscopy (SEM). It is shown that the corrosion resistance of the present FeNiPB BMGs in 0.5 M NaCl and 1 M HCl solution increases with Ni content, and further the present FeNiPB BMGs exhibit larger E{sub corr} values and lower I{sub corr} values, i.e. higher corrosion resistances, than that of stainless steel.

  14. Magneto-thermo-gravimetric technique to investigate the structural and magnetic properties of Fe-B-Nb-Y Bulk Metallic Glass

    Lee, Sangmin; Makino, Akihiro; Inoue, Akihisa [Department of Materials Science, Graduate School of Engineering, Tohoku University, Sendai 980-8579 (Japan); Masood, Ansar; Tamaki, Takahiko; Valter, Strom; Rao, K V, E-mail: smlee@imr.tohoku.ac.j [Royal Institute of Technology (KTH), SE-100 44 Stockhom (Sweden)

    2009-01-01

    Magneto-thermo-gravimetric (MTG) technique is highly informative about the changes in the magnetic state, as well as structural changes in a system, which cannot be often noticed in calorimetric measurements. We demonstrate the versatility of this technique in determining the magnetic transition temperature, and the subsequent crystallization process in a (Fe{sub 0.72}B{sub 0.24}Nb{sub 0.04}){sub 95.5}Y{sub 4.5} Bulk Metallic Glass (BMG). MTG and DSC analyses were carried out at the heating rate of 0.67 K/s from RT {approx}1170 K. As a result of the repeated MTG measurements, a magnetic 2nd amorphous phase was observed in the BMG sample, which could be the first measurement for the Magnetic Short Range Ordering (MSRO). Consequently, the MTG measurement is proved as the most convenient method for determining the various structural and magnetic transitions in a glassy material.

  15. The effect of H- and J-aggregation on the photophysical and photovoltaic properties of small Thiophene–Pyridine–DPP molecules for bulk-heterojunction solar cells

    Más-Montoya, M.; Janssen, R.A.J.

    2017-01-01

    The performance of organic semiconductors in optoelectronic devices depends on the functional properties of the individual molecules and their mutual orientations when they are in the solid state. The effect of H- and J-aggregation on the photophysical properties and photovoltaic behavior of four

  16. Study of tritium permeation through Peach Bottom Steam Generator tubes

    Yang, L.; Baugh, W.A.; Baldwin, N.L.

    1977-06-01

    The report describes the equipment developed, samples tested, procedures used, and results obtained in the tritium permeation tests conducted on steam generator tubing samples which were removed from the Peach Bottom Unit No. 1 reactor

  17. Recent results on implantation and permeation into fusion reactor materials

    Anderl, R. A.; Holland, D. F.; Longhurst, G. R.; Struttman, D. A.

    This paper reports on implantation-driven permeation experiments that have been made for primary candidate alloy (PCA) and the ferritic steel HT-9 using deuterium ion beams from an accelerator. The results include measurements of the implantation flux and fluence dependence of the deuterium reemission and permeation for specimens heated to approximately 430(0)C. Simultaneous measurements of the ions sputtered from the specimen front surface with a secondary ion mass spectrometer provided some characterization of the surface condition throughout an experiment. For both materials, the permeation rate was lowered by the implantation process. However, the steady state permeation rate for HT-9 was found to be at least a factor of 5 greater than that for PCA.

  18. Phase Change Permeation Technology for Environmental Control & Life Support Systems

    National Aeronautics and Space Administration — NASA is evaluating Dutyion™, a phase change permeation membrane technology developed by Design Technology and Irrigation (DTI), for use in future advanced life...

  19. Effect of residual stresses on hydrogen permeation in iron

    Mouanga, M.; Bercot, P.; Takadoum, J.

    2010-01-01

    The effect of residual stresses on electrochemical permeation in iron membrane was investigated. Four thermal and mechanical treatments were chosen to obtain different surface states in relation to the residual stresses. Residual stresses were determined by X-ray diffraction (XRD) using the Macherauch and Mueller method. The results were completed by the microhardness measurements. For all iron membranes, compressive residual stresses were obtained. Electrochemical permeation experiments using a Devanathan and Stachurski cell were employed to determine the hydrogen permeation behaviour of the various iron membranes. The latter was charged with hydrogen by galvanostatic cathodic polarization in 0.1 M NaOH at 25 deg. C. The experimental results revealed that hydrogen permeation rate increases with increasing residual stresses introduced in iron membranes.

  20. Phase evolution and its effect on magnetic properties of Nd sub 6 sub 0 Al sub 1 sub 0 Fe sub 2 sub 0 Co sub 1 sub 0 bulk metallic glass

    Lei Xia; Pan, M X; Zhao, D Q; Wang, W H; Dong, Y D

    2003-01-01

    The thermal stability of nanocrystalline clusters, the phase evolution, and their effects on magnetic properties were studied for as-cast Nd sub 6 sub 0 Al sub 1 sub 0 Fe sub 2 sub 0 Co sub 1 sub 0 alloy using differential scanning calorimetry curves, x-ray diffraction patterns, scanning electron microscopy, and high-resolution transition electron microscopy. Thermomagnetic curves and hysteresis loops of the bulk metallic glass were measured during the annealing process. The high thermostability of the hard magnetic properties of the samples observed is attributed to the stability of the nanocrystalline clusters upon annealing, while the slight enhancement in the magnetization is due to the precipitation of some Nd-rich metastable phases. The mechanism of thermostability of the nanocrystalline clusters and the formation of the metastable phases are discussed.