Sample records for solid phase material

  1. 40 CFR 227.32 - Liquid, suspended particulate, and solid phases of a material.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... solid phases of a material. 227.32 Section 227.32 Protection of Environment ENVIRONMENTAL PROTECTION... MATERIALS Definitions § 227.32 Liquid, suspended particulate, and solid phases of a material. (a) For the... obtained above prior to centrifugation and filtration. The solid phase includes all material settling to...

  2. 40 CFR 227.32 - Liquid, suspended particulate, and solid phases of a material.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... solid phases of a material. 227.32 Section 227.32 Protection of Environment ENVIRONMENTAL PROTECTION... MATERIALS Definitions § 227.32 Liquid, suspended particulate, and solid phases of a material. (a) For the... obtained above prior to centrifugation and filtration. The solid phase includes all material settling to...

  3. Solid state phase change materials for thermal energy storage in passive solar heated buildings

    NASA Astrophysics Data System (ADS)

    Benson, D. K.; Christensen, C.

    1983-11-01

    A set of solid state phase change materials was evaluated for possible use in passive solar thermal energy storage systems. The most promising materials are organic solid solutions of pentaerythritol, pentaglycerine and neopentyl glycol. Solid solution mixtures of these compounds can be tailored so that they exhibit solid-to-solid phase transformations at any desired temperature within the range from less than 25 deg to 188 deg. Thermophysical properties such as thermal conductivity, density and volumetric expansion were measured. Computer simulations were used to predict the performance of various Trombe wall designs incorporating solid state phase change materials. Optimum performance was found to be sensitive to the choice of phase change temperatures and to the thermal conductivity of the phase change material. A molecular mechanism of the solid state phase transition is proposed and supported by infrared spectroscopic evidence.

  4. Materials research for passive solar systems: Solid-state phase-change materials

    NASA Astrophysics Data System (ADS)

    Benson, D. K.; Webb, J. D.; Burrows, R. W.; McFadden, J. D. O.; Christensen, C.

    1985-03-01

    A set of solid-state phase-change materials is being evaluated for possible use in passive solar thermal energy storage systems. The most promising materials are organic solid solutions of pentaerythritol (C5H12O4), pentaglycerinve (C5H12O3), and neopentyl glycol (C5H12O2). Solid solution mixtures of these compounds can be tailored so that they exhibit solid-to-solid phase transformations at any desired temperature between 25 C and 188 C, and have latent heats of transformation etween 20 and 70 cal/g. Transformation temperatures, specific heats, and latent heats of transformation have been measured for a number of these materials. Limited cyclic experiments suggest that the solid solutions are stable. These phase-change materials exhibit large amounts of undercooling; however, the addition of certain nucleating agents as particulate dispersions in the solid phase-change material greatly reduces this effect. Computer simulations suggest that the use of an optimized solid-state phase-change material in a Trombe wall could provide better performance than a concrete Trombe wall four times thicker and nine times heavier.

  5. Engineered glass seals for solid-oxide fuel cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Surdoval, Wayne; Lara-Curzio, Edgar; Stevenson, Jeffry

    2017-02-07

    A seal for a solid oxide fuel cell includes a glass matrix having glass percolation therethrough and having a glass transition temperature below 650.degree. C. A deformable second phase material is dispersed in the glass matrix. The second phase material can be a compliant material. The second phase material can be a crushable material. A solid oxide fuel cell, a precursor for forming a seal for a solid oxide fuel cell, and a method of making a seal for a solid oxide fuel cell are also disclosed.

  6. Crystallization process

    DOEpatents

    Adler, Robert J.; Brown, William R.; Auyang, Lun; Liu, Yin-Chang; Cook, W. Jeffrey

    1986-01-01

    An improved crystallization process is disclosed for separating a crystallizable material and an excluded material which is at least partially excluded from the solid phase of the crystallizable material obtained upon freezing a liquid phase of the materials. The solid phase is more dense than the liquid phase, and it is separated therefrom by relative movement with the formation of a packed bed of solid phase. The packed bed is continuously formed adjacent its lower end and passed from the liquid phase into a countercurrent flow of backwash liquid. The packed bed extends through the level of the backwash liquid to provide a drained bed of solid phase adjacent its upper end which is melted by a condensing vapor.

  7. Solid-solid phase change thermal storage application to space-suit battery pack

    NASA Astrophysics Data System (ADS)

    Son, Chang H.; Morehouse, Jeffrey H.

    1989-01-01

    High cell temperatures are seen as the primary safety problem in the Li-BCX space battery. The exothermic heat from the chemical reactions could raise the temperature of the lithium electrode above the melting temperature. Also, high temperature causes the cell efficiency to decrease. Solid-solid phase-change materials were used as a thermal storage medium to lower this battery cell temperature by utilizing their phase-change (latent heat storage) characteristics. Solid-solid phase-change materials focused on in this study are neopentyl glycol and pentaglycerine. Because of their favorable phase-change characteristics, these materials appear appropriate for space-suit battery pack use. The results of testing various materials are reported as thermophysical property values, and the space-suit battery operating temperature is discussed in terms of these property results.

  8. Modeling of Shock Waves with Multiple Phase Transitions in Condensed Materials

    NASA Astrophysics Data System (ADS)

    Missonnier, Marc; Heuzé, Olivier

    2006-07-01

    When a shock wave crosses a solid material and subjects it to solid-solid or solid-liquid phase transition, related phenomena occur: shock splitting, and the corresponding released shock wave after reflection. Modelling of these phenomena raises physical and numerical issues. After shock loading, such materials can reach different kinds of states: single-phase states, binary-phase states, and triple points. The thermodynamic path can be studied and easily understood in the (V,E) or (V,S) planes. In the case of 3 phase tin (β,γ, and liquid) submitted to shock waves, seven states can occur: β,γ, liquid, β-γ, β-liquid, γ-liquid, and β-γ-liquid. After studying the thermodynamic properties with a complete 3-phase Equation of State, we show the existence of these seven states with a hydrodynamic simulation.

  9. Enhanced densification under shock compression in porous silicon

    NASA Astrophysics Data System (ADS)

    Lane, J. Matthew D.; Thompson, Aidan P.; Vogler, Tracy J.

    2014-10-01

    Under shock compression, most porous materials exhibit lower densities for a given pressure than that of a full-dense sample of the same material. However, some porous materials exhibit an anomalous, or enhanced, densification under shock compression. We demonstrate a molecular mechanism that drives this behavior. We also present evidence from atomistic simulation that silicon belongs to this anomalous class of materials. Atomistic simulations indicate that local shear strain in the neighborhood of collapsing pores nucleates a local solid-solid phase transformation even when bulk pressures are below the thermodynamic phase transformation pressure. This metastable, local, and partial, solid-solid phase transformation, which accounts for the enhanced densification in silicon, is driven by the local stress state near the void, not equilibrium thermodynamics. This mechanism may also explain the phenomenon in other covalently bonded materials.

  10. Review of high-throughput techniques for detecting solid phase Transformation from material libraries produced by combinatorial methods

    NASA Technical Reports Server (NTRS)

    Lee, Jonathan A.

    2005-01-01

    High-throughput measurement techniques are reviewed for solid phase transformation from materials produced by combinatorial methods, which are highly efficient concepts to fabricate large variety of material libraries with different compositional gradients on a single wafer. Combinatorial methods hold high potential for reducing the time and costs associated with the development of new materials, as compared to time-consuming and labor-intensive conventional methods that test large batches of material, one- composition at a time. These high-throughput techniques can be automated to rapidly capture and analyze data, using the entire material library on a single wafer, thereby accelerating the pace of materials discovery and knowledge generation for solid phase transformations. The review covers experimental techniques that are applicable to inorganic materials such as shape memory alloys, graded materials, metal hydrides, ferric materials, semiconductors and industrial alloys.

  11. Investigation on thixojoining to produce hybrid components with intermetallic phase

    NASA Astrophysics Data System (ADS)

    Seyboldt, Christoph; Liewald, Mathias

    2018-05-01

    Current research activities at the Institute for Metal Forming Technology of the University of Stuttgart are focusing on the manufacturing of hybrid components using semi-solid forming strategies. One process investigated is the joining of different materials in the semi-solid state and is so called "thixojoining". In this process, metallic inlays are inserted into the semi-solid forming die before the actual forming process and are then joined with a material which was heated up to its semi-solid state. Earlier investigations have shown that using this process a very well-shaped form closure can be produced. Furthermore, it was found that sometimes intermetallic phases are built between the different materials, which decisively influence the part properties of such hybrid components for its future application. Within the framework presented in this paper, inlays made of aluminum, brass and steel were joined with aluminum in the semi-solid state. The aim of the investigations was to create an intermetallic bond between the different materials. For this investigations the liquid phase fraction of the aluminum and the temperature of the inlay were varied in order to determine the influence on the formation of the intermetallic phase. Forming trials were performed using a semi-solid forming die with a disk shaped design. Furthermore, the intermetallic phase built was investigated using microsections.

  12. Comparison of the solid-phase extraction efficiency of a bounded and an included cyclodextrin-silica microporous composite for polycyclic aromatic hydrocarbons determination in water samples.

    PubMed

    Mauri-Aucejo, Adela; Amorós, Pedro; Moragues, Alaina; Guillem, Carmen; Belenguer-Sapiña, Carolina

    2016-08-15

    Solid-phase extraction is one of the most important techniques for sample purification and concentration. A wide variety of solid phases have been used for sample preparation over time. In this work, the efficiency of a new kind of solid-phase extraction adsorbent, which is a microporous material made from modified cyclodextrin bounded to a silica network, is evaluated through an analytical method which combines solid-phase extraction with high-performance liquid chromatography to determine polycyclic aromatic hydrocarbons in water samples. Several parameters that affected the analytes recovery, such as the amount of solid phase, the nature and volume of the eluent or the sample volume and concentration influence have been evaluated. The experimental results indicate that the material possesses adsorption ability to the tested polycyclic aromatic hydrocarbons. Under the optimum conditions, the quantification limits of the method were in the range of 0.09-2.4μgL(-1) and fine linear correlations between peak height and concentration were found around 1.3-70μgL(-1). The method has good repeatability and reproducibility, with coefficients of variation under 8%. Due to the concentration results, this material may represent an alternative for trace analysis of polycyclic aromatic hydrocarbons in water trough solid-phase extraction. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Solid materials for removing arsenic and method thereof

    DOEpatents

    Coronado, Paul R.; Coleman, Sabre J.; Sanner, Robert D.; Dias, Victoria L.; Reynolds, John G.

    2010-09-28

    Solid materials have been developed to remove arsenic compounds from aqueous media. The arsenic is removed by passing the aqueous phase through the solid materials which can be in molded, granular, or powder form. The solid materials adsorb the arsenic leaving a purified aqueous stream. The materials are aerogels or xerogels and aerogels or xerogels and solid support structure, e.g., granulated activated carbon (GAC), mixtures. The species-specific adsorption occurs through specific chemical modifications of the solids tailored towards arsenic.

  14. Solid materials for removing arsenic and method thereof

    DOEpatents

    Coronado, Paul R [Livermore, CA; Coleman, Sabre J [Oakland, CA; Sanner, Robert D [Livermore, CA; Dias, Victoria L [Livermore, CA; Reynolds, John G [San Ramon, CA

    2008-07-01

    Solid materials have been developed to remove arsenic compounds from aqueous media. The arsenic is removed by passing the aqueous phase through the solid materials which can be in molded, granular, or powder form. The solid materials adsorb the arsenic leaving a purified aqueous stream. The materials are aerogels or xerogels and aerogels or xerogels and solid support structure, e.g., granulated activated carbon (GAC), mixtures. The species-specific adsorption occurs through specific chemical modifications of the solids tailored towards arsenic.

  15. Enhanced densification under shock compression in porous silicon

    DOE PAGES

    Lane, J. Matthew; Thompson, Aidan Patrick; Vogler, Tracy

    2014-10-27

    Under shock compression, most porous materials exhibit lower densities for a given pressure than that of a full-dense sample of the same material. However, some porous materials exhibit an anomalous, or enhanced, densification under shock compression. The mechanism driving this behavior was not completely determined. We present evidence from atomistic simulation that pure silicon belongs to this anomalous class of materials and demonstrate the associated mechanisms responsible for the effect in porous silicon. Atomistic response indicates that local shear strain in the neighborhood of collapsing pores catalyzes a local solid-solid phase transformation even when bulk pressures are below the thermodynamicmore » phase transformation pressure. This metastable, local, and partial, solid-solid phase transformation, which accounts for the enhanced densification in silicon, is driven by the local stress state near the void, not equilibrium thermodynamics. This mechanism may also explain the phenomenon in other covalently bonded materials.« less

  16. A study of room-temperature LixMn1.5Ni0.5O4 solid solutions

    NASA Astrophysics Data System (ADS)

    Saravanan, Kuppan; Jarry, Angelique; Kostecki, Robert; Chen, Guoying

    2015-01-01

    Understanding the kinetic implication of solid-solution vs. biphasic reaction pathways is critical for the development of advanced intercalation electrode materials. Yet this has been a long-standing challenge in materials science due to the elusive metastable nature of solid solution phases. The present study reports the synthesis, isolation, and characterization of room-temperature LixMn1.5Ni0.5O4 solid solutions. In situ XRD studies performed on pristine and chemically-delithiated, micron-sized single crystals reveal the thermal behavior of LixMn1.5Ni0.5O4 (0 <= x <= 1) cathode material consisting of three cubic phases: LiMn1.5Ni0.5O4 (Phase I), Li0.5Mn1.5Ni0.5O4 (Phase II) and Mn1.5Ni0.5O4 (Phase III). A phase diagram capturing the structural changes as functions of both temperature and Li content was established. The work not only demonstrates the possibility of synthesizing alternative electrode materials that are metastable in nature, but also enables in-depth evaluation on the physical, electrochemical and kinetic properties of transient intermediate phases and their role in battery electrode performance.

  17. Solid materials for removing metals and fabrication method

    DOEpatents

    Coronado, Paul R.; Reynolds, John G.; Coleman, Sabre J.

    2004-10-19

    Solid materials have been developed to remove contaminating metals and organic compounds from aqueous media. The contaminants are removed by passing the aqueous phase through the solid materials which can be in molded, granular, or powder form. The solid materials adsorb the metals and the organics leaving a purified aqueous stream. The materials are sol-gel and or sol-gel and granulated activated carbon (GAC) mixtures. The species-specific adsorption occurs through specific chemical modifications of the solids tailored towards the contaminant(s). The contaminated solid materials can then be disposed of or the contaminant can be removed and the solids recycled.

  18. A novel mechanical model for phase-separation in debris flows

    NASA Astrophysics Data System (ADS)

    Pudasaini, Shiva P.

    2015-04-01

    Understanding the physics of phase-separation between solid and fluid phases as a two-phase mass moves down slope is a long-standing challenge. Here, I propose a fundamentally new mechanism, called 'separation-flux', that leads to strong phase-separation in avalanche and debris flows. This new model extends the general two-phase debris flow model (Pudasaini, 2012) to include a separation-flux mechanism. The new flux separation mechanism is capable of describing and controlling the dynamically evolving phase-separation, segregation, and/or levee formation in a real two-phase, geometrically three-dimensional debris flow motion and deposition. These are often observed phenomena in natural debris flows and industrial processes that involve the transportation of particulate solid-fluid mixture material. The novel separation-flux model includes several dominant physical and mechanical aspects that result in strong phase-separation (segregation). These include pressure gradients, volume fractions of solid and fluid phases and their gradients, shear-rates, flow depth, material friction, viscosity, material densities, boundary structures, gravity and topographic constraints, grain shape, size, etc. Due to the inherent separation mechanism, as the mass moves down slope, more and more solid particles are brought to the front, resulting in a solid-rich and mechanically strong frontal surge head followed by a weak tail largely consisting of the viscous fluid. The primary frontal surge head followed by secondary surge is the consequence of the phase-separation. Such typical and dominant phase-separation phenomena are revealed here for the first time in real two-phase debris flow modeling and simulations. However, these phenomena may depend on the bulk material composition and the applied forces. Reference: Pudasaini, Shiva P. (2012): A general two-phase debris flow model. J. Geophys. Res., 117, F03010, doi: 10.1029/2011JF002186.

  19. Molecular Simulation of the Free Energy for the Accurate Determination of Phase Transition Properties of Molecular Solids

    NASA Astrophysics Data System (ADS)

    Sellers, Michael; Lisal, Martin; Brennan, John

    2015-06-01

    Investigating the ability of a molecular model to accurately represent a real material is crucial to model development and use. When the model simulates materials in extreme conditions, one such property worth evaluating is the phase transition point. However, phase transitions are often overlooked or approximated because of difficulty or inaccuracy when simulating them. Techniques such as super-heating or super-squeezing a material to induce a phase change suffer from inherent timescale limitations leading to ``over-driving,'' and dual-phase simulations require many long-time runs to seek out what frequently results in an inexact location of phase-coexistence. We present a compilation of methods for the determination of solid-solid and solid-liquid phase transition points through the accurate calculation of the chemical potential. The methods are applied to the Smith-Bharadwaj atomistic potential's representation of cyclotrimethylene trinitramine (RDX) to accurately determine its melting point (Tm) and the alpha to gamma solid phase transition pressure. We also determine Tm for a coarse-grain model of RDX, and compare its value to experiment and atomistic counterpart. All methods are employed via the LAMMPS simulator, resulting in 60-70 simulations that total 30-50 ns. Approved for public release. Distribution is unlimited.

  20. Subscale solid motor nozzle tests, phase 4 and nozzle materials screening and thermal characterization, phase 5

    NASA Technical Reports Server (NTRS)

    Arnold, J.; Dodson, J.; Laub, B.

    1979-01-01

    Subscale solid motor nozzles containing a baseline material or low cost materials to be considered as potential replacements for the baseline material are designed and tested. Data are presented from tests of four identically designed 2.5 inch throat diameter nozzles and one 7 inch throat diameter nozzle. The screening of new candidate low cost materials, as well as their thermophysical and thermochemical characterization is also discussed.

  1. Further insight into the mechanism of heavy metals partitioning in stormwater runoff.

    PubMed

    Djukić, Aleksandar; Lekić, Branislava; Rajaković-Ognjanović, Vladana; Veljović, Djordje; Vulić, Tatjana; Djolić, Maja; Naunovic, Zorana; Despotović, Jovan; Prodanović, Dušan

    2016-03-01

    Various particles and materials, including pollutants, deposited on urban surfaces are washed off by stormwater runoff during rain events. The interactions between the solid and dissolved compounds in stormwater runoff are phenomena of importance for the selection and improvement of optimal stormwater management practices aimed at minimizing pollutant input to receiving waters. The objective of this research was to further investigate the mechanisms responsible for the partitioning of heavy metals (HM) between the solid and liquid phases in urban stormwater runoff. The research involved the collection of samples from urban asphalt surfaces, chemical characterization of the bulk liquid samples, solids separation, particle size distribution fractionation and chemical and physico-chemical characterization of the solid phase particles. The results revealed that a negligible fraction of HM was present in the liquid phase (less than 3% by weight), while there was a strong correlation between the total content of heavy metals and total suspended solids. Examinations of surface morphology and mineralogy revealed that the solid phase particles consist predominantly of natural macroporous materials: alpha quartz (80%), magnetite (11.4%) and silicon diphosphate (8.9%). These materials have a low surface area and do not have significant adsorptive capacity. These materials have a low surface area and do not have significant adsorptive capacity. The presence of HM on the surface of solid particles was not confirmed by scanning electron microscopy and energy dispersive X-ray microanalyses. These findings, along with the results of the liquid phase sample characterization, indicate that the partitioning of HM between the liquid and solid phases in the analyzed samples may be attributed to precipitation processes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Solid electrolyte-electrode system for an electrochemical cell

    DOEpatents

    Tuller, Harry L.; Kramer, Steve A.; Spears, Marlene A.

    1995-01-01

    An electrochemical device including a solid electrolyte and solid electrode composed of materials having different chemical compositions and characterized by different electrical properties but having the same crystalline phase is provided. A method for fabricating an electrochemical device having a solid electrode and solid electrolyte characterized by the same crystalline phase is also provided.

  3. Ammonium nitrate-polymer glasses: a new concept for phase and thermal stabilization of ammonium nitrate.

    PubMed

    Lang, Anthony J; Vyazovkin, Sergey

    2008-09-11

    Dissolving of ammonium nitrate in highly polar polymers such as poly(vinylpyrrolidone) and/or poly(acrylamide) can result in the formation of single-phase glassy solid materials, in which NH 4 (+) and NO 3 (-) are separated through an ion-dipole interaction with the polymer matrix. Below the glass transition temperature of the polymer matrix the resulting materials remain phase and thermally stable as demonstrated through the absence of decomposition as well as the solid-solid transitions and melting of ammonium nitrate. The structure of the materials is explored by Fourier transform infrared spectroscopy and density functional calculations. Differential scanning calorimetry, thermogravimetry, and isoconversional kinetic analysis are applied to characterize the thermal behavior of the materials.

  4. A study of room-temperature LixMn1.5Ni0.5O4 solid solutions

    PubMed Central

    Saravanan, Kuppan; Jarry, Angelique; Kostecki, Robert; Chen, Guoying

    2015-01-01

    Understanding the kinetic implication of solid-solution vs. biphasic reaction pathways is critical for the development of advanced intercalation electrode materials. Yet this has been a long-standing challenge in materials science due to the elusive metastable nature of solid solution phases. The present study reports the synthesis, isolation, and characterization of room-temperature LixMn1.5Ni0.5O4 solid solutions. In situ XRD studies performed on pristine and chemically-delithiated, micron-sized single crystals reveal the thermal behavior of LixMn1.5Ni0.5O4 (0 ≤ x ≤ 1) cathode material consisting of three cubic phases: LiMn1.5Ni0.5O4 (Phase I), Li0.5Mn1.5Ni0.5O4 (Phase II) and Mn1.5Ni0.5O4 (Phase III). A phase diagram capturing the structural changes as functions of both temperature and Li content was established. The work not only demonstrates the possibility of synthesizing alternative electrode materials that are metastable in nature, but also enables in-depth evaluation on the physical, electrochemical and kinetic properties of transient intermediate phases and their role in battery electrode performance. PMID:25619504

  5. A study of room-temperature Li xMn 1.5Ni 0.5O 4 solid solutions

    DOE PAGES

    Saravanan, Kuppan; Jarry, Angelique; Kostecki, Robert; ...

    2015-01-26

    Understanding the kinetic implication of solid-solution vs. biphasic reaction pathways is critical for the development of advanced intercalation electrode materials. Yet this has been a long-standing challenge in materials science due to the elusive metastable nature of solid solution phases. The present study reports the synthesis, isolation, and characterization of room-temperature Li xMn 1.5Ni 0.5O 4 solid solutions. In situ XRD studies performed on pristine and chemically-delithiated, micron-sized single crystals reveal the thermal behavior of Li xMn 1.5Ni 0.5O 4 (0 ≤ x ≤ 1) cathode material consisting of three cubic phases: LiMn 1.5Ni 0.5O 4 (Phase I), Li 0.5Mnmore » 1.5Ni 0.5O 4 (Phase II) and Mn 1.5Ni 0.5O 4 (Phase III). A phase diagram capturing the structural changes as functions of both temperature and Li content was established. In conclusion, the work not only demonstrates the possibility of synthesizing alternative electrode materials that are metastable in nature, but also enables in-depth evaluation on the physical, electrochemical and kinetic properties of transient intermediate phases and their role in battery electrode performance.« less

  6. Experimental Method Development for Estimating Solid-phase Diffusion Coefficients and Material/Air Partition Coefficients of SVOCs

    EPA Science Inventory

    The solid-phase diffusion coefficient (Dm) and material-air partition coefficient (Kma) are key parameters for characterizing the sources and transport of semivolatile organic compounds (SVOCs) in the indoor environment. In this work, a new experimental method was developed to es...

  7. Method for making an electrochemical cell

    DOEpatents

    Tuller, Harry L.; Kramer, Steve A.; Spears, Marlene A.; Pal, Uday B.

    1996-01-01

    An electrochemical device including a solid electrolyte and solid electrode composed of materials having different chemical compositions and characterized by different electrical properties but having the same crystalline phase is provided. A method for fabricating an electrochemical device having a solid electrode and solid electrolyte characterized by the same crystalline phase is provided.

  8. Solid electrolyte-electrode system for an electrochemical cell

    DOEpatents

    Tuller, H.L.; Kramer, S.A.; Spears, M.A.

    1995-04-04

    An electrochemical device including a solid electrolyte and solid electrode composed of materials having different chemical compositions and characterized by different electrical properties but having the same crystalline phase is provided. A method for fabricating an electrochemical device having a solid electrode and solid electrolyte characterized by the same crystalline phase is also provided. 17 figures.

  9. Method for removing solid particulate material from within liquid fuel injector assemblies

    DOEpatents

    Simandl, R.F.; Brown, J.D.; Andriulli, J.B.; Strain, P.D.

    1998-09-08

    A method is described for removing residual solid particulate material from the interior of liquid fuel injectors and other fluid flow control mechanisms having or being operatively associated with a flow-regulating fixed or variable orifice. The method comprises the sequential and alternate introduction of columns of a non-compressible liquid phase and columns of a compressed gas phase into the body of a fuel injector whereby the expansion of each column of the gas phase across the orifice accelerates the liquid phase in each trailing column of the liquid phase and thereby generates turbulence in each liquid phase for lifting and entraining the solid particulates for the subsequent removal thereof from the body of the fuel injector. 1 fig.

  10. Method for removing solid particulate material from within liquid fuel injector assemblies

    DOEpatents

    Simandl, Ronald F.; Brown, John D.; Andriulli, John B.; Strain, Paul D.

    1998-01-01

    A method for removing residual solid particulate material from the interior of liquid fuel injectors and other fluid flow control mechanisms having or being operatively associated with a flow-regulating fixed or variable orifice. The method comprises the sequential and alternate introduction of columns of a non-compressible liquid phase and columns of a compressed gas phase into the body of a fuel injector whereby the expansion of each column of the gas phase across the orifice accelerates the liquid phase in each trailing column of the liquid phase and thereby generates turbulence in each liquid phase for lifting and entraining the solid particulates for the subsequent removal thereof from the body of the fuel injector.

  11. Two-dimensional solid-phase extraction strategy for the selective enrichment of aminoglycosides in milk.

    PubMed

    Shen, Aijin; Wei, Jie; Yan, Jingyu; Jin, Gaowa; Ding, Junjie; Yang, Bingcheng; Guo, Zhimou; Zhang, Feifang; Liang, Xinmiao

    2017-03-01

    An orthogonal two-dimensional solid-phase extraction strategy was established for the selective enrichment of three aminoglycosides including spectinomycin, streptomycin, and dihydrostreptomycin in milk. A reversed-phase liquid chromatography material (C 18 ) and a weak cation-exchange material (TGA) were integrated in a single solid-phase extraction cartridge. The feasibility of two-dimensional clean-up procedure that experienced two-step adsorption, two-step rinsing, and two-step elution was systematically investigated. Based on the orthogonality of reversed-phase and weak cation-exchange procedures, the two-dimensional solid-phase extraction strategy could minimize the interference from the hydrophobic matrix existing in traditional reversed-phase solid-phase extraction. In addition, high ionic strength in the extracts could be effectively removed before the second dimension of weak cation-exchange solid-phase extraction. Combined with liquid chromatography and tandem mass spectrometry, the optimized procedure was validated according to the European Union Commission directive 2002/657/EC. A good performance was achieved in terms of linearity, recovery, precision, decision limit, and detection capability in milk. Finally, the optimized two-dimensional clean-up procedure incorporated with liquid chromatography and tandem mass spectrometry was successfully applied to the rapid monitoring of aminoglycoside residues in milk. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Phase Transformations and Microstructural Evolution: Part II

    DOE PAGES

    Clarke, Amy Jean

    2015-10-30

    The activities of the Phase Transformations Committee of the Materials Processing & Manufacturing Division (MPMD) of The Minerals, Metals & Materials Society (TMS) are oriented toward understanding the fundamental aspects of phase transformations. Emphasis is placed on the thermodynamic driving forces for phase transformations, the kinetics of nucleation and growth, interfacial structures and energies, transformation crystallography, surface reliefs, and, above all, the atomic mechanisms of phase transformations. Phase transformations and microstructural evolution are directly linked to materials processing, properties, and performance. In this issue, aspects of liquid–solid and solid-state phase transformations and microstructural evolution are highlighted. Many papers in thismore » issue are highlighted by this paper, giving a brief summary of what they bring to the scientific community.« less

  13. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kirka, Michael M.; Nandwana, Peeyush; Lee, Yousub

    Additive manufacturing (AM) of metals is rapidly emerging as an established manufacturing process for metal components. Unlike traditional metals fabrication processes, metals fabricated via AM undergo localized thermal cycles during fabrication. As a result, AM presents the opportunity to control the liquid-solid phase transformation, i.e. material texture. But, thermal cycling presents challenges from the standpoint of solid-solid phase transformations. We will discuss the opportunities and challenges in metals AM in the context of texture control and associated solid-solid phase transformations in Ti-6Al-4V and Inconel 718.

  14. Method and apparatus for acoustic plate mode liquid-solid phase transition detection

    DOEpatents

    Blair, Dianna S.; Freye, Gregory C.; Hughes, Robert C.; Martin, Stephen J.; Ricco, Antonio J.

    1993-01-01

    A method and apparatus for sensing a liquid-solid phase transition event is provided which comprises an acoustic plate mode detecting element placed in contact with a liquid or solid material which generates a high-frequency acoustic wave that is attenuated to an extent based on the physical state of the material is contact with the detecting element. The attenuation caused by the material in contact with the acoustic plate mode detecting element is used to determine the physical state of the material being detected. The method and device are particularly suited for detecting conditions such as the icing and deicing of wings of an aircraft. In another aspect of the present invention, a method is provided wherein the adhesion of a solid material to the detecting element can be measured using the apparatus of the invention.

  15. Solidification and solid-state transformation sciences in metals additive manufacturing

    DOE PAGES

    Kirka, Michael M.; Nandwana, Peeyush; Lee, Yousub; ...

    2017-02-11

    Additive manufacturing (AM) of metals is rapidly emerging as an established manufacturing process for metal components. Unlike traditional metals fabrication processes, metals fabricated via AM undergo localized thermal cycles during fabrication. As a result, AM presents the opportunity to control the liquid-solid phase transformation, i.e. material texture. But, thermal cycling presents challenges from the standpoint of solid-solid phase transformations. We will discuss the opportunities and challenges in metals AM in the context of texture control and associated solid-solid phase transformations in Ti-6Al-4V and Inconel 718.

  16. Nanostructured lipid carriers: effect of solid phase fraction and distribution on the release of encapsulated materials.

    PubMed

    Dan, Nily

    2014-11-25

    Emulsions, solid lipid nanoparticles (SLN), and nanostructured lipid carriers (NLC) containing a mix of liquid and solid domains are of interest as encapsulation vehicles for hydrophobic compounds. Studies of the release rate from these particles yield contradictory results: Some find that increasing the fraction of solid phase increases the rate of release and others the opposite. In this paper we study the release of encapsulated materials from lipid-based nanoparticles using Monte Carlo simulations. We find that, quite surprisingly, the release rate is largely insensitive to the size of solid domains or the fraction of solid phase. However, the distribution of the domains significantly affects the rate of release: Solid domains located at the interface with the surrounding solution inhibit transport, while nanoparticles where the solid domains are concentrated in the center enhance it. The latter can lead to release rates in NLCs that are faster than in the equivalent emulsions. We conclude that controlling the release rate from NLCs requires the ability to determine the location and distribution of the solid phase, which may be achieved through choice of the surfactants stabilizing the particles, incorporation of nucleation sites, and/or the cooling rates and temperatures.

  17. Complexities of One-Component Phase Diagrams

    ERIC Educational Resources Information Center

    Ciccioli, Andrea; Glasser, Leslie

    2011-01-01

    For most materials, the solid at and near the triple-point temperature is denser than the liquid with which it is in equilibrium. However, for water and certain other materials, the densities of the phases are reversed, with the solid being less dense. The profound consequences for the appearance of the "pVT" diagram of one-component materials…

  18. Effect of Process Parameter on Barium Titanate Stannate (BTS) Materials Sintered at Low Sintering

    NASA Astrophysics Data System (ADS)

    Shukla, Alok; Bajpai, P. K.

    2011-11-01

    Ba(Ti1-xSnx)O3 solid solutions with (x = 0.15, 0.20, 0.30 and 0.40) are synthesized using conventional solid state reaction method. Formation of solid solutions in the range 0 ≤ x ≤0.40 is confirmed using X-ray diffraction technique. Single phase solid solutions with homogeneous grain distribution are observed at relatively low sintering by controlling process parameters viz. sintering time. Composition at optimized temperature (1150 °C) sintered by varying the sintering time, stabilize in cubic perovskite phase. The % experimental density increase with increasing the time of sintering instead of increasing sintering temperature. The lattice parameter increases by increasing the tin composition in the material. This demonstrates that process parameter optimization can lead to single phase at relatively lower sintering-a major advantage for the materials used as capacitor element in MLCC.

  19. Structure and transport properties of a plastic crystal ion conductor: diethyl(methyl)(isobutyl)phosphonium hexafluorophosphate.

    PubMed

    Jin, Liyu; Nairn, Kate M; Forsyth, Craig M; Seeber, Aaron J; MacFarlane, Douglas R; Howlett, Patrick C; Forsyth, Maria; Pringle, Jennifer M

    2012-06-13

    Understanding the ion transport behavior of organic ionic plastic crystals (OIPCs) is crucial for their potential application as solid electrolytes in various electrochemical devices such as lithium batteries. In the present work, the ion transport mechanism is elucidated by analyzing experimental data (single-crystal XRD, multinuclear solid-state NMR, DSC, ionic conductivity, and SEM) as well as the theoretical simulations (second moment-based solid static NMR line width simulations) for the OIPC diethyl(methyl)(isobutyl)phosphonium hexafluorophosphate ([P(1,2,2,4)][PF(6)]). This material displays rich phase behavior and advantageous ionic conductivities, with three solid-solid phase transitions and a highly "plastic" and conductive final solid phase in which the conductivity reaches 10(-3) S cm(-1). The crystal structure shows unique channel-like packing of the cations, which may allow the anions to diffuse more easily than the cations at lower temperatures. The strongly phase-dependent static NMR line widths of the (1)H, (19)F, and (31)P nuclei in this material have been well simulated by different levels of molecular motions in different phases. Thus, drawing together of the analytical and computational techniques has allowed the construction of a transport mechanism for [P(1,2,2,4)][PF(6)]. It is also anticipated that utilization of these techniques will allow a more detailed understanding of the transport mechanisms of other plastic crystal electrolyte materials.

  20. High-Resolution Solid-State NMR Spectroscopy: Characterization of Polymorphism in Cimetidine, a Pharmaceutical Compound

    ERIC Educational Resources Information Center

    Pacilio, Julia E.; Tokarski, John T.; Quiñones, Rosalynn; Iuliucci, Robbie J.

    2014-01-01

    High-resolution solid-state NMR (SSNMR) spectroscopy has many advantages as a tool to characterize solid-phase material that finds applications in polymer chemistry, nanotechnology, materials science, biomolecular structure determination, and others, including the pharmaceutical industry. The technology associated with achieving high resolution…

  1. Thermophysical Properties of Fluid Latent Heat Storage Material using Urea-Water Mixture

    NASA Astrophysics Data System (ADS)

    Hokamura, Taku; Ohkubo, Hidetoshi; Ashizawa, Kiyonori

    This study is concerned with the measurement of thermophysical properties of a urea-water mixture with the aim of adopting the mixture as a latent heat storage material for air-conditioning systems. The urea-water mixture is made of natural substances and has a good fluidity. The urea concentration in the mixture was controlled by measuring the refractive index of the mixture. Being a multi-component substance, a urea-water solution has a liquid-solid co-existent phase on a phase-diagram. Therefore, the liquidus temperature was measured to establish a relationship between the fraction of the solid-phase and temperature. Furthermore, apparent values of specific heat and coefficient of viscosity were measured in the two-phase region where the solid phase is ice. The apparent specific heat and coefficient of viscosity were measure by using an adiabatic calorimeter and a stirring torque meter respectively. The results revealed that the urea-water mixture can probably be used as a latent heat storage material of good fluidity.

  2. Preparation and characterization of novel anion phase change heat storage materials.

    PubMed

    Hong, Wei; Lil, Qingshan; Sun, Jing; Di, Youbo; Zhao, Zhou; Yu, Wei'an; Qu, Yuan; Jiao, TiFeng; Wang, Guowei; Xing, Guangzhong

    2013-10-01

    In this paper, polyurethane phase change material was successfully prepared with TDI with BDO for hard segments and PEG for soft segments. Moreover, based on this the solid-solid phase change material, A-PCM1030 which can release anions was prepared with the successful addition of anion additives A1030 for the first time. Then the test of the above material was conducted utilizing FT-IR, DSC, TEM, WAXD and Air Ion Detector. The Results indicated that the polyurethane phase change material possesses excellent thermal stability since there was no appearance of liquid leakage and phase separation after 50 times warming-cooling thermal cycles. It also presented reversibility on absorbing and releasing heat. In addition, adding a little A1030 can increase the thermal stability and reduce phase transition temperatures, as well as reduce the undercooling of the polyurethane phase change material. In addition, the anion test results suggested that the supreme amount of anion released by A-PCM1030 could reach 2510 anions/cm3 under dynamic conditions, which is beneficial for human health.

  3. Melting of Simple Solids and the Elementary Excitations of the Communal Entropy

    NASA Astrophysics Data System (ADS)

    Bongiorno, Angelo

    2010-03-01

    The melting phase transition of simple solids is addressed through the use of atomistic computer simulations. Three transition metals (Ni, Au, and Pt) and a semiconductor (Si) are considered in this study. Iso-enthalpic molecular dynamics simulations are used to compute caloric curves across the solid-to-liquid phase transition of a periodic crystalline system, to construct the free energy function of the solid and liquid phases, and thus to derive the thermodynamical limit of the melting point, latent heat and entropy of fusion of the material. The computational strategy used in this study yields accurate estimates of melting parameters, it consents to determine the superheating and supercooling temperature limits, and it gives access to the atomistic mechanisms mediating the melting process. In particular, it is found that the melting phase transition in simple solids is driven by exchange steps involving a few atoms and preserving the crystalline structure. These self-diffusion phenomena correspond to the elementary excitations of the communal entropy and, as their rate depends on the local material cohesivity, they mediate both the homogeneous and non-homogeneous melting process in simple solids.

  4. Solid phase extraction membrane

    DOEpatents

    Carlson, Kurt C [Nashville, TN; Langer, Roger L [Hudson, WI

    2002-11-05

    A wet-laid, porous solid phase extraction sheet material that contains both active particles and binder and that possesses excellent wet strength is described. The binder is present in a relatively small amount while the particles are present in a relatively large amount. The sheet material is sufficiently strong and flexible so as to be pleatable so that, for example, it can be used in a cartridge device.

  5. Solid catalyzed isoparaffin alkylation at supercritical fluid and near-supercritical fluid conditions

    DOEpatents

    Ginosar, Daniel M.; Fox, Robert V.; Kong, Peter C.

    2000-01-01

    This invention relates to an improved method for the alkylation reaction of isoparaffins with olefins over solid catalysts including contacting a mixture of an isoparaffin, an olefin and a phase-modifying material with a solid acid catalyst member under alkylation conversion conditions at either supercritical fluid, or near-supercritical fluid conditions, at a temperature and a pressure relative to the critical temperature(T.sub.c) and the critical pressure(P.sub.c) of the reaction mixture. The phase-modifying phase-modifying material is employed to promote the reaction's achievement of either a supercritical fluid state or a near-supercritical state while simultaneously allowing for decreased reaction temperature and longer catalyst life.

  6. Disorder-induced localization in crystalline phase-change materials.

    PubMed

    Siegrist, T; Jost, P; Volker, H; Woda, M; Merkelbach, P; Schlockermann, C; Wuttig, M

    2011-03-01

    Localization of charge carriers in crystalline solids has been the subject of numerous investigations over more than half a century. Materials that show a metal-insulator transition without a structural change are therefore of interest. Mechanisms leading to metal-insulator transition include electron correlation (Mott transition) or disorder (Anderson localization), but a clear distinction is difficult. Here we report on a metal-insulator transition on increasing annealing temperature for a group of crystalline phase-change materials, where the metal-insulator transition is due to strong disorder usually associated only with amorphous solids. With pronounced disorder but weak electron correlation, these phase-change materials form an unparalleled quantum state of matter. Their universal electronic behaviour seems to be at the origin of the remarkable reproducibility of the resistance switching that is crucial to their applications in non-volatile-memory devices. Controlling the degree of disorder in crystalline phase-change materials might enable multilevel resistance states in upcoming storage devices.

  7. An effect of surface properties on detachment of adhered solid to cooling surface for formation of clathrate hydrate slurry

    NASA Astrophysics Data System (ADS)

    Daitoku, Tadafumi; Utaka, Yoshio

    In air-conditioning systems, it is desirable that the liquid-solid phase change temperature of a cool energy storage material is approximately 10 °C from the perspective of improving coefficient of performance (COP). Moreover, a thermal storage material that forms slurry can realize large heat capacity of working fluids. Since the solid that adheres to the heat transfer surface forms a thermal resistance layer and remarkably reduces the rate of cold storage, it is important to avoid the adhesion of a thick solid layer on the surface so as to realize efficient energy storage. Considering a harvest type cooling unit, the force required for removing the solid phase from the heat transfer surface was studied. Tetra-n-butylammonium Bromide (TBAB) clathrate hydrate was used as a cold storage material. The effect of the heat transfer surface properties on the scraping force for detachment of adhered solid of TBAB hydrate to the heat transfer surface was examined experimentally.

  8. Replacement of Ablators with Phase-Change Material for Thermal Protection of STS Elements

    NASA Technical Reports Server (NTRS)

    Kaul, Raj K.; Stuckey, Irvin; Munafo, Paul M. (Technical Monitor)

    2002-01-01

    As part of the research and development program to develop new Thermal Protection System (TPS) materials for aerospace applications at NASA's Marshall Space Flight Center (MSFC), an experimental study was conducted on a new concept for a non-ablative TPS material. Potential loss of TPS material and ablation by-products from the External Tank (ET) or Solid Rocket Booster (SRB) during Shuttle flight with the related Orbiter tile damage necessitates development of a non-ablative thermal protection system. The new Thermal Management Coating (TMC) consists of phase-change material encapsulated in micro spheres and a two-part resin system to adhere the coating to the structure material. The TMC uses a phase-change material to dissipate the heat produced during supersonic flight rather than an ablative material. This new material absorbs energy as it goes through a phase change during the heating portion of the flight profile and then the energy is slowly released as the phase-change material cools and returns to its solid state inside the micro spheres. The coating was subjected to different test conditions simulating design flight environments at the NASA/MSFC Improved Hot Gas Facility (IHGF) to study its performance.

  9. Microwave impregnation of porous materials with thermal energy storage materials

    DOEpatents

    Benson, David K.; Burrows, Richard W.

    1993-01-01

    A method for impregnating a porous, non-metallic construction material with a solid phase-change material is described. The phase-change material in finely divided form is spread onto the surface of the porous material, after which the porous material is exposed to microwave energy for a time sufficient to melt the phase-change material. The melted material is spontaneously absorbed into the pores of the porous material. A sealing chemical may also be included with the phase-change material (or applied subsequent to the phase-change material) to seal the surface of the porous material. Fire retardant chemicals may also be included with the phase-change materials. The treated construction materials are better able to absorb thermal energy and exhibit increased heat storage capacity.

  10. Microwave impregnation of porous materials with thermal energy storage materials

    DOEpatents

    Benson, D.K.; Burrows, R.W.

    1993-04-13

    A method for impregnating a porous, non-metallic construction material with a solid phase-change material is described. The phase-change material in finely divided form is spread onto the surface of the porous material, after which the porous material is exposed to microwave energy for a time sufficient to melt the phase-change material. The melted material is spontaneously absorbed into the pores of the porous material. A sealing chemical may also be included with the phase-change material (or applied subsequent to the phase-change material) to seal the surface of the porous material. Fire retardant chemicals may also be included with the phase-change materials. The treated construction materials are better able to absorb thermal energy and exhibit increased heat storage capacity.

  11. Collection-efficient, axisymmetric vacuum sublimation module for the purification of solid materials.

    PubMed

    May, Michael; Paul, Elizabeth; Katovic, Vladimir

    2015-11-01

    A vacuum sublimation module of axisymmetric geometry was developed and employed to purify solid-phase materials. The module provides certain practical advantages and it comprises: a metering valve, glass collector, glass lower body, main seal, threaded bushing, and glass internal cartridge (the latter to contain starting material). A complementary process was developed to de-solvate, sublime, weigh, and collect solid chemical materials exemplified by oxalic acid, ferrocene, pentachlorobenzene, chrysene, and urea. The oxalic acid sublimate was analyzed by titration, melting range, Fourier Transform Infrared (FT-IR) Spectroscopy, cyclic voltammetry, and its (aqueous phase) electrolytically generated gas. The analytical data were consistent with a high-purity, anhydrous oxalic acid sublimate. Cyclic voltammograms of 0.11 mol. % oxalic acid in water displayed a 2.1 V window on glassy carbon electrode beyond which electrolytic decomposition occurs. During module testing, fifteen relatively pure materials were sublimed with (energy efficient) passive cooling and the solid-phase recovery averaged 95 mass %. Key module design features include: compact vertical geometry, low-angle conical collector, uniformly compressed main seal, modest power consumption, transparency, glovebox compatibility, cooling options, and preferential conductive heat transfer. To help evaluate the structural (module) heat transfer, vertical temperature profiles along the dynamically evacuated lower body were measured versus electric heater power: for example, an input of 18.6 W generated a temperature 443-K at the bottom. Experimental results and engineering calculations indicate that during sublimation, solid conduction is the primary mode of heat transfer to the starting material.

  12. Wave transmission approach based on modal analysis for embedded mechanical systems

    NASA Astrophysics Data System (ADS)

    Cretu, Nicolae; Nita, Gelu; Ioan Pop, Mihail

    2013-09-01

    An experimental method for determining the phase velocity in small solid samples is proposed. The method is based on measuring the resonant frequencies of a binary or ternary solid elastic system comprising the small sample of interest and a gauge material of manageable size. The wave transmission matrix of the combined system is derived and the theoretical values of its eigenvalues are used to determine the expected eigenfrequencies that, equated with the measured values, allow for the numerical estimation of the phase velocities in both materials. The known phase velocity of the gauge material is then used to asses the accuracy of the method. Using computer simulation and the experimental values for phase velocities, the theoretical values for the eigenfrequencies of the eigenmodes of the embedded elastic system are obtained, to validate the method. We conclude that the proposed experimental method may be reliably used to determine the elastic properties of small solid samples whose geometries do not allow a direct measurement of their resonant frequencies.

  13. Extensively Reversible Thermal Transformations of a Bistable, Fluorescence-Switchable Molecular Solid: Entry into Functional Molecular Phase-Change Materials.

    PubMed

    Srujana, P; Radhakrishnan, T P

    2015-06-15

    Functional phase-change materials (PCMs) are conspicuously absent among molecular materials in which the various attributes of inorganic solids have been realized. While organic PCMs are primarily limited to thermal storage systems, the amorphous-crystalline transformation of materials like Ge-Sb-Te find use in advanced applications such as information storage. Reversible amorphous-crystalline transformations in molecular solids require a subtle balance between robust supramolecular assembly and flexible structural elements. We report novel diaminodicyanoquinodimethanes that achieve this transformation by interlinked helical assemblies coupled with conformationally flexible alkoxyalkyl chains. They exhibit highly reversible thermal transformations between bistable (crystalline/amorphous) forms, along with a prominent switching of the fluorescence emission energy and intensity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Phase Relations in Ternary Systems in the Subsolidus Region: Methods to Formulate Solid Solution Equations and to Find Particular Compositions

    ERIC Educational Resources Information Center

    Alvarez-Montan~o, Victor E.; Farías, Mario H.; Brown, Francisco; Mun~oz-Palma, Iliana C.; Cubillas, Fernando; Castillon-Barraza, Felipe F.

    2017-01-01

    A good understanding of ternary phase diagrams is required to advance and/or to reproduce experimental research in solid-state and materials chemistry. The aim of this paper is to describe the solutions to problems that appear when studying or determining ternary phase diagrams. A brief description of the principal features shown in phase diagrams…

  15. THE FEASIBILITY OF UTILIZING SOLID WASTES FOR BUILDING MATERIALS. EXECUTIVE SUMMARY

    EPA Science Inventory

    This report focuses on two phases of a suggested four phase study to evaluate the technological and commercial possibilities of waste - derived composites. The first phase involved a joint and comprehensive literature search to identify wastes with potential as building materials...

  16. Solid-phase extraction microfluidic devices for matrix removal in trace element assay of actinide materials

    DOE PAGES

    Gao, Jun; Manard, Benjamin Thomas; Castro, Alonso; ...

    2017-02-02

    Advances in sample nebulization and injection technology have significantly reduced the volume of solution required for trace impurity analysis in plutonium and uranium materials. Correspondingly, we have designed and tested a novel chip-based microfluidic platform, containing a 100-µL or 20-µL solid-phase microextraction column, packed by centrifugation, which supports nuclear material mass and solution volume reductions of 90% or more compared to standard methods. Quantitative recovery of 28 trace elements in uranium was demonstrated using a UTEVA chromatographic resin column, and trace element recovery from thorium (a surrogate for plutonium) was similarly demonstrated using anion exchange resin AG MP-1. Of ninemore » materials tested, compatibility of polyvinyl chloride (PVC), polypropylene (PP), and polytetrafluoroethylene (PTFE) chips with the strong nitric acid media was highest. Finally, the microcolumns can be incorporated into a variety of devices and systems, and can be loaded with other solid-phase resins for trace element assay in high-purity metals.« less

  17. Solid-phase extraction microfluidic devices for matrix removal in trace element assay of actinide materials

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gao, Jun; Manard, Benjamin Thomas; Castro, Alonso

    Advances in sample nebulization and injection technology have significantly reduced the volume of solution required for trace impurity analysis in plutonium and uranium materials. Correspondingly, we have designed and tested a novel chip-based microfluidic platform, containing a 100-µL or 20-µL solid-phase microextraction column, packed by centrifugation, which supports nuclear material mass and solution volume reductions of 90% or more compared to standard methods. Quantitative recovery of 28 trace elements in uranium was demonstrated using a UTEVA chromatographic resin column, and trace element recovery from thorium (a surrogate for plutonium) was similarly demonstrated using anion exchange resin AG MP-1. Of ninemore » materials tested, compatibility of polyvinyl chloride (PVC), polypropylene (PP), and polytetrafluoroethylene (PTFE) chips with the strong nitric acid media was highest. Finally, the microcolumns can be incorporated into a variety of devices and systems, and can be loaded with other solid-phase resins for trace element assay in high-purity metals.« less

  18. Investigation of the Ignition and Burning of Materials in Space Cabin Atmospheres. Part 1: Ignition and Burning of Material

    NASA Technical Reports Server (NTRS)

    Lew, H. G.

    1972-01-01

    An analytical study of the theory of ignition and burning of a plastic material immersed in an atmosphere of a space cabin which may be subjected to gravity force changes is considered. The hazardous condition in a space cabin environment where the changes of gravity may effect the combustion process is evaluated. The model considered the analysis of the coupled gas and solid phases and is based on the premise that material heating leads to the formation of pyrolysis gases from the decomposed solid which then react with the ambient oxidizer to further the combustion process. Moreover, free convection plays a dominant role in transporting these hot gases to the virgin material. A time-dependent study of the coupled gas-solid model as required for ignition processes with emphasis on the surface energy interchange of the gas and solid phases has been made. Detailed distribution of species composition and temperature patterns provide a spatial and time map of the evolving gases from the material combustion.

  19. Minimization of Poisson’s ratio in anti-tetra-chiral two-phase structure

    NASA Astrophysics Data System (ADS)

    Idczak, E.; Strek, T.

    2017-10-01

    One of the most important goal of modern material science is designing structures which exhibit appropriate properties. These properties can be obtained by optimization methods which often use numerical calculations e.g. finite element method (FEM). This paper shows the results of topological optimization which is used to obtain the greatest possible negative Poisson’s ratio of the two-phase composite. The shape is anti-tetra-chiral two-dimensional unit cell of the whole lattice structure which has negative Poisson’s ratio when it is built of one solid material. Two phase used in optimization are two solid materials with positive Poisson’s ratio and Young’s modulus. Distribution of reinforcement hard material inside soft matrix material in anti-tetra-chiral domain influenced mechanical properties of structure. The calculations shows that the resultant structure has negative Poisson’s ratio even eight times smaller than homogenous anti-tetra chiral structure made of classic one material. In the analysis FEM is connected with algorithm Method of Moving Asymptote (MMA). The results of materials’ properties parameters are described and calculated by means of shape interpolation scheme - Solid Isotropic Material with Penalization (SIMP) method.

  20. The use of lipids as phase change materials for thermal energy storage

    USDA-ARS?s Scientific Manuscript database

    Phase change materials (PCMs) are substances capable of absorbing and releasing large 2 amounts of thermal energy (heat or cold) as latent heat over constant temperature as they 3 undergo a change in state of matter (phase transition), commonly, between solid and 4 liquid phases. Since the late 194...

  1. Heating of solid earthen material, measuring moisture and resistivity

    DOEpatents

    Heath, William O.; Gauglitz, Phillip A.; Pillay, Gautam; Bergsman, Theresa M.; Eschbach, Eugene A.; Goheen, Steven C.; Richardson, Richard L.; Roberts, Janet S.; Schalla, Ronald

    1996-01-01

    The present invention includes a method of treating solid earthen material having volatile, semi-volatile, and non-volatile contaminants that utilizes electrical energy. A plurality of electrodes are inserted into a region of earthen material to be treated in a selected geometric pattern. Varying phase and voltages configurations are applied to corresponding electrodes to achieve heating, physical phase changes, and the placement of substances within the treatment region. Additionally, treatment mediums can be added to either treat the contamination within the soil or to restrict their mobility.

  2. Heating of solid earthen material, measuring moisture and resistivity

    DOEpatents

    Heath, W.O.; Gauglitz, P.A.; Pillay, G.; Bergsman, T.M.; Eschbach, E.A.; Goheen, S.C.; Richardson, R.L.; Roberts, J.S.; Schalla, R.

    1996-08-13

    The present invention includes a method of treating solid earthen material having volatile, semi-volatile, and non-volatile contaminants that utilizes electrical energy. A plurality of electrodes are inserted into a region of earthen material to be treated in a selected geometric pattern. Varying phase and voltages configurations are applied to corresponding electrodes to achieve heating, physical phase changes, and the placement of substances within the treatment region. Additionally, treatment mediums can be added to either treat the contamination within the soil or to restrict their mobility. 29 figs.

  3. Phase diagram of nanoscale alloy particles used for vapor-liquid-solid growth of semiconductor nanowires.

    PubMed

    Sutter, Eli; Sutter, Peter

    2008-02-01

    We use transmission electron microscopy observations to establish the parts of the phase diagram of nanometer sized Au-Ge alloy drops at the tips of Ge nanowires (NWs) that determine their temperature-dependent equilibrium composition and, hence, their exchange of semiconductor material with the NWs. We find that the phase diagram of the nanoscale drop deviates significantly from that of the bulk alloy, which explains discrepancies between actual growth results and predictions on the basis of the bulk-phase equilibria. Our findings provide the basis for tailoring vapor-liquid-solid growth to achieve complex one-dimensional materials geometries.

  4. Boron-Based Hydrogen Storage: Ternary Borides and Beyond

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Vajo, John J.

    DOE continues to seek reversible solid-state hydrogen materials with hydrogen densities of ≥11 wt% and ≥80 g/L that can deliver hydrogen and be recharged at moderate temperatures (≤100 °C) and pressures (≤100 bar) enabling incorporation into hydrogen storage systems suitable for transportation applications. Boron-based hydrogen storage materials have the potential to meet the density requirements given boron’s low atomic weight, high chemical valance, and versatile chemistry. However, the rates of hydrogen exchange in boron-based compounds are thus far much too slow for practical applications. Although contributing to the high hydrogen densities, the high valance of boron also leads to slowmore » rates of hydrogen exchange due to extensive boron-boron atom rearrangements during hydrogen cycling. This rearrangement often leads to multiple solid phases occurring over hydrogen release and recharge cycles. These phases must nucleate and react with each other across solid-solid phase boundaries leading to energy barriers that slow the rates of hydrogen exchange. This project sought to overcome the slow rates of hydrogen exchange in boron-based hydrogen storage materials by minimizing the number of solid phases and the boron atom rearrangement over a hydrogen release and recharge cycle. Two novel approaches were explored: 1) developing matched pairs of ternary borides and mixed-metal borohydrides that could exchange hydrogen with only one hydrogenated phase (the mixed-metal borohydride) and only one dehydrogenated phase (the ternary boride); and 2) developing boranes that could release hydrogen by being lithiated using lithium hydride with no boron-boron atom rearrangement.« less

  5. An automatic granular structure generation and finite element analysis of heterogeneous semi-solid materials

    NASA Astrophysics Data System (ADS)

    Sharifi, Hamid; Larouche, Daniel

    2015-09-01

    The quality of cast metal products depends on the capacity of the semi-solid metal to sustain the stresses generated during the casting. Predicting the evolution of these stresses with accuracy in the solidification interval should be highly helpful to avoid the formation of defects like hot tearing. This task is however very difficult because of the heterogeneous nature of the material. In this paper, we propose to evaluate the mechanical behaviour of a metal during solidification using a mesh generation technique of the heterogeneous semi-solid material for a finite element analysis at the microscopic level. This task is done on a two-dimensional (2D) domain in which the granular structure of the solid phase is generated surrounded by an intergranular and interdendritc liquid phase. Some basic solid grains are first constructed and projected in the 2D domain with random orientations and scale factors. Depending on their orientation, the basic grains are combined to produce larger grains or separated by a liquid film. Different basic grain shapes can produce different granular structures of the mushy zone. As a result, using this automatic grain generation procedure, we can investigate the effect of grain shapes and sizes on the thermo-mechanical behaviour of the semi-solid material. The granular models are automatically converted to the finite element meshes. The solid grains and the liquid phase are meshed properly using quadrilateral elements. This method has been used to simulate the microstructure of a binary aluminium-copper alloy (Al-5.8 wt% Cu) when the fraction solid is 0.92. Using the finite element method and the Mie-Grüneisen equation of state for the liquid phase, the transient mechanical behaviour of the mushy zone under tensile loading has been investigated. The stress distribution and the bridges, which are formed during the tensile loading, have been detected.

  6. Solid-phase materials for chelating metal ions and methods of making and using same

    DOEpatents

    Harrup, Mason K.; Wey, John E.; Peterson, Eric S.

    2003-06-10

    A solid material for recovering metal ions from aqueous streams, and methods of making and using the solid material, are disclosed. The solid material is made by covalently bonding a chelating agent to a silica-based solid, or in-situ condensing ceramic precursors along with the chelating agent to accomplish the covalent bonding. The chelating agent preferably comprises a oxime type chelating head, preferably a salicylaldoxime-type molecule, with an organic tail covalently bonded to the head. The hydrocarbon tail includes a carbon-carbon double bond, which is instrumental in the step of covalently bonding the tail to the silica-based solid or the in-situ condensation. The invented solid material may be contacted directly with aqueous streams containing metal ions, and is selective to ions such as copper (II) even in the presence of such ions as iron (III) and other materials that are present in earthen materials. The solid material with high selectivity to copper may be used to recover copper from mining and plating industry streams, to replace the costly and toxic solvent extraction steps of conventional copper processing.

  7. A review on development of solid phase microextraction fibers by sol-gel methods and their applications.

    PubMed

    Kumar, Ashwini; Gaurav; Malik, Ashok Kumar; Tewary, Dhananjay Kumar; Singh, Baldev

    2008-03-03

    Solid phase microextraction (SPME) is an innovative, solvent free technology that is fast, economical and versatile. SPME is a fiber coated with a liquid (polymer), a solid (sorbent) or a combination of both. The fiber coating takes up the compounds from the sample by absorption in the case of liquid coatings or adsorption in the case of solid coatings. The SPME fiber is then transferred with the help of a syringe like device into the analytical instrument for desorption and analysis of the target analytes. The sol-gel process provides a versatile method to prepare size, shape and charge selective materials of high purity and homogeneity by means of preparation techniques different from the traditional ones, for the chemical analysis. This review is on the current state of the art and future trends in the developments of solid phase microextraction (SPME) fibers using sol-gel method. To achieve more selective determination of different compound classes, the variety of different coating material for SPME fibers has increased. Further developments in SPME as a highly efficient extraction technique, will greatly depend on new breakthroughs in the area of new coating material developments for the SPME fibers. In sol-gel approach, appropriate sol-gel precursors and other building blocks can be selected to create a stationary phase with desired structural and surface properties. This approach is efficient in integrating the advantageous properties of organic and inorganic material systems and thereby increasing and improving the extraction selectivity of the produced amalgam organic-inorganic stationary phases. This review is mainly focused on recent advanced developments in the design, synthesis, characterisation, properties and application of sol-gel in preparation of coatings for the SPME fibers.

  8. Discovering Volatile Chemicals from Window Weatherstripping through Solid-Phase Microextraction/Gas Chromatography-Mass Spectrometry

    ERIC Educational Resources Information Center

    Rosu, Cornelia; Cueto, Rafael; Veillion, Lucas; David, Connie; Laine, Roger A.; Russo, Paul S.

    2017-01-01

    Volatile compounds from polymeric materials such as weatherstripping were identified by solid-phase microextraction (SPME), a solvent-free analytical method, coupled to gas chromatography-mass spectrometry (GC-MS). These compounds, originating from additives and fillers used in weatherstripping processing, were mostly polycyclic aromatic…

  9. Headspace analysis of polar organic compounds in biological matrixes using solid phase microextraction (SPME)

    USDA-ARS?s Scientific Manuscript database

    Analysis of biological fluids and waste material is difficult and tedious given the sample matrix. A rapid automated method for the determination of volatile fatty acids and phenolic and indole compounds was developed using a multipurpose sampler (MPS) with solid phase microextraction (SPME) and GC-...

  10. Method of producing particulate-reinforced composites and composites produced thereby

    DOEpatents

    Han, Qingyou; Liu, Zhiwei

    2013-12-24

    A process for producing particle-reinforced composite materials through utilization of an in situ reaction to produce a uniform dispersion of a fine particulate reinforcement phase. The process includes forming a melt of a first material, and then introducing particles of a second material into the melt and subjecting the melt to high-intensity acoustic vibration. A chemical reaction initiates between the first and second materials to produce reaction products in the melt. The reaction products comprise a solid particulate phase, and the high-intensity acoustic vibration fragments and/or separates the reaction products into solid particles that are dispersed in the melt and are smaller than the particles of the second material. Also encompassed are particle-reinforced composite materials produced by such a process.

  11. Method of producing particulate-reinforced composites and composites produced thereby

    DOEpatents

    Han, Qingyou; Liu, Zhiwei

    2015-12-29

    A process for producing particle-reinforced composite materials through utilization of an in situ reaction to produce a uniform dispersion of a fine particulate reinforcement phase. The process includes forming a melt of a first material, and then introducing particles of a second material into the melt and subjecting the melt to high-intensity acoustic vibration. A chemical reaction initiates between the first and second materials to produce reaction products in the melt. The reaction products comprise a solid particulate phase, and the high-intensity acoustic vibration fragments and/or separates the reaction products into solid particles that are dispersed in the melt and are smaller than the particles of the second material. Also encompassed are particle-reinforced composite materials produced by such a process.

  12. Method of producing particulate-reinforced composites and composties produced thereby

    DOEpatents

    Han, Qingyou; Liu, Zhiwei

    2013-12-24

    A process for producing particle-reinforced composite materials through utilization of an in situ reaction to produce a uniform dispersion of a fine particulate reinforcement phase. The process includes forming a melt of a first material, and then introducing particles of a second material into the melt and subjecting the melt to high-intenisty acoustic vibration. A chemical reaction initiates between the first and second materials to produce reaction products in the melt. The reaciton products comprise a solide particulate phase, and the high-intensity acoustic vibration fragments and/or separates the reaction products into solid particles that are dispersed in the melt and are smaller than the particles of the second material. Also encompassed are particles-reinforced composite materials produced by such a process.

  13. Microwave assisted solid phase extraction for separation preconcentration sulfamethoxazole in wastewater using tyre based activated carbon as solid phase material prior to spectrophotometric determination

    NASA Astrophysics Data System (ADS)

    Mogolodi Dimpe, K.; Mpupa, Anele; Nomngongo, Philiswa N.

    2018-01-01

    This work was chiefly encouraged by the continuous consumption of antibiotics which eventually pose harmful effects on animals and human beings when present in water systems. In this study, the activated carbon (AC) was used as a solid phase material for the removal of sulfamethoxazole (SMX) in wastewater samples. The microwave assisted solid phase extraction (MASPE) as a sample extraction method was employed to better extract SMX in water samples and finally the analysis of SMX was done by the UV-Vis spectrophotometer. The microwave assisted solid phase extraction method was optimized using a two-level fractional factorial design by evaluating parameters such as pH, mass of adsorbent (MA), extraction time (ET), eluent ratio (ER) and microwave power (MP). Under optimized conditions, the limit of detection (LOD) and limit of quantification (LOQ) were 0.5 μg L- 1 and 1.7 μg L- 1, respectively, and intraday and interday precision expressed in terms of relative standard deviation were > 6%.The maximum adsorption capacity was 138 mg g- 1 for SMX and the adsorbent could be reused eight times. Lastly, the MASPE method was applied for the removal of SMX in wastewater samples collected from a domestic wastewater treatment plant (WWTP) and river water.

  14. Chemically and compositionally modified solid solution disordered multiphase nickel hydroxide positive electrode for alkaline rechargeable electrochemical cells

    DOEpatents

    Ovshinsky, Stanford R.; Corrigan, Dennis; Venkatesan, Srini; Young, Rosa; Fierro, Christian; Fetcenko, Michael A.

    1994-01-01

    A high capacity, long cycle life positive electrode for use in an alkaline rechargeable electrochemical cell comprising: a solid solution nickel hydroxide material having a multiphase structure that comprises at least one polycrystalline .gamma.-phase including a polycrystalline .gamma.-phase unit cell comprising spacedly disposed plates with at least one chemical modifier incorporated around the plates, the plates having a range of stable intersheet distances corresponding to a 2.sup.+ oxidation state and a 3.5.sup.+, or greater, oxidation state; and at least one compositional modifier incorporated into the solid solution nickel hydroxide material to promote the multiphase structure.

  15. Results of Copper-Silver Rail Materials Tests

    DTIC Science & Technology

    2006-05-01

    dislocation-dense grain structure. An annealing, recrystallization , and re-straining model is proposed to predict the bandwidth within which the...darker phase is the copper-rich solid solution, while the lighter regions are the eutectic structure consisting of both copper-rich and silver-rich solid...solutions. The eutectic phase ribbons consist of finer copper and silver filaments [1], [5]. The two phases are inhomogeneously deformed during the

  16. Imprinted magnetic graphene oxide for the mini-solid phase extraction of Eu (III) from coal mine area

    NASA Astrophysics Data System (ADS)

    Patra, Santanu; Roy, Ekta; Madhuri, Rashmi; Sharma, Prashant K.

    2017-05-01

    The present work represents the preparation of imprinted magnetic reduced graphene oxide and applied it for the selective removal of Eu (III) from local coal mines area. A simple solid phase extraction method was used for this purpose. The material shows a very high adsorption as well as removal efficiency towards Eu (III), which suggest that the material have potential to be used in future for their real time applications in removal of Eu (III) from complex matrices.

  17. Building Materials from Colloidal Nanocrystal Assemblies: Molecular Control of Solid/Solid Interfaces in Nanostructured Tetragonal ZrO 2

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shaw, Santosh; Silva, Tiago F.; Bobbitt, Jonathan M.

    We describe in this paper a bottom-up approach to control the composition of solid/solid interfaces in nanostructured materials, and we test its effectiveness on tetragonal ZrO 2, an inorganic phase of great technological significance. Colloidal nanocrystals capped with trioctylphosphine oxide (TOPO) or oleic acid (OA) are deposited, and the organic fraction of the ligands is selectively etched with O 2 plasma. The interfaces in the resulting all-inorganic colloidal nanocrystal assemblies are either nearly bare (for OA-capped nanocrystals) or terminated with phosphate groups (for TOPO-capped nanocrystals) resulting from the reaction of phosphine oxide groups with plasma species. The chemical modification ofmore » the interfaces has extensive effects on the thermodynamics and kinetics of the material. Different growth kinetics indicate different rate limiting processes of growth (surface diffusion for the phosphate-terminated surfaces and dissolution for the “bare” surfaces). Phosphate termination led to a higher activation energy of growth, and a 3-fold reduction in interfacial energy, and facilitated significantly the conversion of the tetragonal phase into the monoclinic phase. Finally, films devoid of residual ligands persisted in the tetragonal phase at temperatures as high as 900 °C for 24 h.« less

  18. Building Materials from Colloidal Nanocrystal Assemblies: Molecular Control of Solid/Solid Interfaces in Nanostructured Tetragonal ZrO 2

    DOE PAGES

    Shaw, Santosh; Silva, Tiago F.; Bobbitt, Jonathan M.; ...

    2017-08-28

    We describe in this paper a bottom-up approach to control the composition of solid/solid interfaces in nanostructured materials, and we test its effectiveness on tetragonal ZrO 2, an inorganic phase of great technological significance. Colloidal nanocrystals capped with trioctylphosphine oxide (TOPO) or oleic acid (OA) are deposited, and the organic fraction of the ligands is selectively etched with O 2 plasma. The interfaces in the resulting all-inorganic colloidal nanocrystal assemblies are either nearly bare (for OA-capped nanocrystals) or terminated with phosphate groups (for TOPO-capped nanocrystals) resulting from the reaction of phosphine oxide groups with plasma species. The chemical modification ofmore » the interfaces has extensive effects on the thermodynamics and kinetics of the material. Different growth kinetics indicate different rate limiting processes of growth (surface diffusion for the phosphate-terminated surfaces and dissolution for the “bare” surfaces). Phosphate termination led to a higher activation energy of growth, and a 3-fold reduction in interfacial energy, and facilitated significantly the conversion of the tetragonal phase into the monoclinic phase. Finally, films devoid of residual ligands persisted in the tetragonal phase at temperatures as high as 900 °C for 24 h.« less

  19. Computer modelling of solid alkali metal carboxylates

    NASA Astrophysics Data System (ADS)

    Barreto, L. S.; Mort, K. A.; Jackson, R. A.; Alves, O. L.

    2000-11-01

    A computational study of solid lithium acetate dihydrate and anhydrous sodium acetate is presented. Interatomic potentials are obtained by empirical fitting to experimental structural data for both materials and the resulting potentials were found to be transferable to different phases of the same materials, giving good agreement with the experimental structure.

  20. A unified momentum equation approach for computing thermal residual stresses during melting and solidification

    NASA Astrophysics Data System (ADS)

    Yeo, Haram; Ki, Hyungson

    2018-03-01

    In this article, we present a novel numerical method for computing thermal residual stresses from a viewpoint of fluid-structure interaction (FSI). In a thermal processing of a material, residual stresses are developed as the material undergoes melting and solidification, and liquid, solid, and a mixture of liquid and solid (or mushy state) coexist and interact with each other during the process. In order to accurately account for the stress development during phase changes, we derived a unified momentum equation from the momentum equations of incompressible fluids and elastoplastic solids. In this approach, the whole fluid-structure system is treated as a single continuum, and the interaction between fluid and solid phases across the mushy zone is naturally taken into account in a monolithic way. For thermal analysis, an enthalpy-based method was employed. As a numerical example, a two-dimensional laser heating problem was considered, where a carbon steel sheet was heated by a Gaussian laser beam. Momentum and energy equations were discretized on a uniform Cartesian grid in a finite volume framework, and temperature-dependent material properties were used. The austenite-martensite phase transformation of carbon steel was also considered. In this study, the effects of solid strains, fluid flow, mushy zone size, and laser heating time on residual stress formation were investigated.

  1. Study on biphasic material model and mechanical analysis of knee joint cartilage

    NASA Astrophysics Data System (ADS)

    Nakatani, A.; Sakashita, A.

    2008-02-01

    A material model of articular cartilage is formulated, and fundamental problems are analyzed. The soft tissue is assumed to comprise two phases: solid and fluid. The biphasic theory proposed by Spilker and Suh (1990) to deal with such materials is reviewed, and some new additional analyses are carried out on the basis of this theory. Assuming the elasticity for the solid phase and introducing the pressure, which is defined by the product of the volume change and penalty coefficient, it is shown that the viscoelastic property of the soft tissue can be reproduced. A preferable solution is obtained for the solid phase by using the reduction integral, even if a high-order interpolation function is used. However, the high-order element cannot satisfactorily capture the velocity distribution of fluids. The pressure distribution is studied by assuming the change in the surface characteristics of the cartilage tissue with the progress of osteoarthritis. The pressure is strongly related to the lubrication conditions, i.e., perfect lubrication, perfect adhesion, and partial adhesion.

  2. Conditioning of carbonaceous material prior to physical beneficiation

    DOEpatents

    Warzinski, Robert P.; Ruether, John A.

    1987-01-01

    A carbonaceous material such as coal is conditioned by contact with a supercritical fluid prior to physical beneficiation. The solid feed material is contacted with an organic supercritical fluid such as cyclohexane or methanol at temperatures slightly above the critical temperature and pressures of 1 to 4 times the critical pressure. A minor solute fraction is extracted into critical phase and separated from the solid residuum. The residuum is then processed by physical separation such as by froth flotation or specific gravity separation to recover a substantial fraction thereof with reduced ash content. The solute in supercritical phase can be released by pressure reduction and recombined with the low-ash, carbonaceous material.

  3. Method to separate lignin-rich solid phase from acidic biomass suspension at an acidic pH

    DOEpatents

    Yasarla, Kumar Lakshmi Rakesh; Ramarao, Bandaru V; Amidon, Thomas

    2017-09-05

    A method of separating a lignin-rich solid phase from a solution suspension, by pretreating a lignocellulosic biomass with a pretreatment fluid having remove soluble components, colloidal material and primarily lignin containing particles; separating the pretreated lignocellulosic biomass from the pretreatment fluid with soluble components, colloidal material and primarily lignin containing particles; flocculating the separated pretreatment fluid with soluble components, colloidal material and primarily lignin containing particles using polyethylene oxide (i.e., PEO) or cationic Poly acrylamide (i.e., CPAM) as a flocculating agent; and filtering the flocculated separated pretreatment fluid with soluble components, colloidal material and primarily lignin containing particles to remove agglomerates.

  4. Method and apparatus for nucleating the crystallization of undercooled materials

    DOEpatents

    Benson, David K.; Barret, Peter F.

    1989-01-01

    A method of storing and controlling a release of latent heat of transition of a phase-change material is disclosed. The method comprises trapping a crystallite of the material between two solid objects and retaining it there under high pressure by applying a force to press the two solid objects tightly together. A crystallite of the material is exposed to a quantity of the material that is in a supercooled condition to nucleate the crystallization of the supercooled material.

  5. Microanalytical Efforts in Support of NASA's Materials Science Programs

    NASA Technical Reports Server (NTRS)

    Gillies, Donald C.

    2004-01-01

    Following a brief overview of NASA s Microgravity Materials Science programs, specific examples will be given showing electron beam and optical microscopic applications to two-phase glass structures, dendrite tip radii, solid solution semiconductors, undercooled two-phase stainless steels and meteorites.

  6. Sewage sludge as a fuel and raw material for phosphorus recovery: Combined process of gasification and P extraction.

    PubMed

    Gorazda, K; Tarko, B; Werle, S; Wzorek, Z

    2018-03-01

    Increasing problems associated with sewage sludge disposal are observed nowadays. As the thermal conversion of sewage sludge (combustion, co-combustion, gasification and pyrolysis) appears to be the most promising alternative for its management, the solid residues left after gasification were examined. The present study evaluates the potential of this waste as an alternative phosphorus source in the context of phosphorus recovery. The obtained solid gasification residues were characterised (chemical and phase composition, thermal properties, surface properties and technological parameters used for phosphorus raw materials) and compared to commercial phosphate raw materials. It was revealed that gasification residue is a valuable source of phosphorus and microelements, comparable to sewage sludge ash (SSA) considered nowadays as secondary phosphorus raw materials. Chemical properties as well as technological parameters characteristic for natural phosphate ores are different. Solid gasification residue was leached with mineral acids (phosphoric and nitric) according to the patented method of phosphorus recovery - PolFerAsh, developed by Cracow University of Technology. It was revealed that phosphorus can be selectively leached from solid gasification residue with high efficiency (73-82%); moreover, most of the iron and heavy metals stay in the solid phase due to the low concentration of acids and proper solid to liquid phase ratio. The obtained leachates are valuable products that can be considered for the production of fertilisers. Combining the gasification process with nutrient recovery provides the opportunity for more environmentally efficient technologies driven by sustainable development rules. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Modelling solid solutions with cluster expansion, special quasirandom structures, and thermodynamic approaches

    NASA Astrophysics Data System (ADS)

    Saltas, V.; Horlait, D.; Sgourou, E. N.; Vallianatos, F.; Chroneos, A.

    2017-12-01

    Modelling solid solutions is fundamental in understanding the properties of numerous materials which are important for a range of applications in various fields including nanoelectronics and energy materials such as fuel cells, nuclear materials, and batteries, as the systematic understanding throughout the composition range of solid solutions for a range of conditions can be challenging from an experimental viewpoint. The main motivation of this review is to contribute to the discussion in the community of the applicability of methods that constitute the investigation of solid solutions computationally tractable. This is important as computational modelling is required to calculate numerous defect properties and to act synergistically with experiment to understand these materials. This review will examine in detail two examples: silicon germanium alloys and MAX phase solid solutions. Silicon germanium alloys are technologically important in nanoelectronic devices and are also relevant considering the recent advances in ternary and quaternary groups IV and III-V semiconductor alloys. MAX phase solid solutions display a palette of ceramic and metallic properties and it is anticipated that via their tuning they can have applications ranging from nuclear to aerospace industries as well as being precursors for particular MXenes. In the final part, a brief summary assesses the limitations and possibilities of the methodologies discussed, whereas there is discussion on the future directions and examples of solid solution systems that should prove fruitful to consider.

  8. Beamline Electrostatic Levitator (BESL) for in-situ High Energy K-Ray Diffraction Studies of Levitated Solids and Liquids at High Temperature

    NASA Technical Reports Server (NTRS)

    Gangopadhyay, A. K.; Lee, G. W.; Kelton, K. F.; Rogers, J. R.; Goldman, A. I.; Robinson, D. S.; Rathz, T. J.; Hyers, R. W.

    2005-01-01

    Determinations of the phase formation sequence, the crystal structures and the thermodynamic properties of materials at high temperatures are difficult because of contamination from the sample container and environment. Containerless processing techniques, such as electrostatic (ESL), electromagnetic (EML), aerodynamic, and acoustic levitation, are most suitable these studies. An adaptation of ESL for in-situ structural studies of a wide range of materials, including metals, semiconductors, insulators using high energy (125 keV) synchrotron x-rays is described here. This beamline ESL (BESL) allows the in-situ determination of the atomic structures of equilibrium solid and liquid phases, including undercooled liquids, as well as real-time studies of solid-solid and liquid-solid phase transformations. The use of image plate (MAR345) or GE-Angio detectors enables fast (30 ms - 1s) acquisition of complete diffraction patterns over a wide q-range (4 - 140/mm). The wide temperature range (300 - 2500 K), containerless processing under high vacuum (10(exp -7) - 10(exp -8) torr), and fast data acquisition, make BESL particularly suitable for phase diagram studies of high temperature materials. An additional, critically important, feature of BESL is the ability to also make simultaneous measurement of a host of thermo-physical properties, including the specific heat, enthalpy of transformation, solidus and liquidus temperatures, density, viscosity, and surface tension; all on the same sample and simultaneous with the structural measurements.

  9. Nonstoichiometric fluorides—Solid electrolytes for electrochemical devices: A review

    NASA Astrophysics Data System (ADS)

    Sorokin, N. I.; Sobolev, B. P.

    2007-09-01

    The solid electrolytes with fluorine-ion conductivity that were revealed during the analysis of the phase diagrams of the MF m - RF n systems within the program of search for new multicomponent fluoride crystalline materials carried out at the Shubnikov Institute of Crystallography, Russian Academy of Sciences, are described. The most widespread and promising materials are the nonstoichiometric phases with fluorite (CaF2) and tysonite (LaF3) structures, which are formed in the MF2- RF3 systems ( M = Ca, Sr, Ba, Cd, or Pb; R = Sc, Y, or La-Lu). These phases have superionic fluorine conductivity due to the anion sublattice disorder. The ionic conductivity of crystals of both structure types has been studied and the limits of its change with composition and temperature are determined. Nonstoichiometric fluorides are used as solid electrolytes in chemical sensors, fluorine sources, and batteries. The prospects of the use of fluorine-ion conductors in solid-state electrochemical devices, principles of their operation, and the problems of optimization of their composition are discussed.

  10. Homogeneous synthesis of cellulose acrylate-g-poly (n-alkyl acrylate) solid-solid phase change materials via free radical polymerization.

    PubMed

    Qian, Yong-Qiang; Han, Na; Bo, Yi-Wen; Tan, Lin-Li; Zhang, Long-Fei; Zhang, Xing-Xiang

    2018-08-01

    A novel solid-solid phase change materials, namely, cellulose acrylate-g-poly (n-alkyl acrylate) (CA-g-PAn) (n = 14, 16 and 18) were successfully synthesized by free radical polymerization in N, N-dimethylacetamide (DMAc). The successful grafting was confirmed by fourier transform infrared spectra (FT-IR) and nuclear magnetic resonance (NMR). The properties of the CA-g-PAn copolymers were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA). The phase change temperatures and the melting enthalpies of CA-g-PAn copolymers are in the range of 10.1-53.2 °C and 15-95 J/g, respectively. It can be adjusted by the contents of poly (n-alkyl acrylate) and the length of alkyl side-chain. The thermal resistant temperatures of CA-g-PA14, 16 and 18 copolymers are 308 °C, 292 °C and 273 °C, respectively. It show that all of grafting materials exhibit good thermal stability and shape stability. Therefore, it is expected to be applied in the cellulose-based thermos-regulating field. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. A New Class of Ternary Compound for Lithium-Ion Battery: from Composite to Solid Solution.

    PubMed

    Wang, Jiali; Wu, Hailong; Cui, Yanhua; Liu, Shengzhou; Tian, Xiaoqing; Cui, Yixiu; Liu, Xiaojiang; Yang, Yin

    2018-02-14

    Searching for high-performance cathode materials is a crucial task to develop advanced lithium-ion batteries (LIBs) with high-energy densities for electrical vehicles (EVs). As a promising lithium-rich material, Li 2 MnO 3 delivers high capacity over 200 mAh g -1 but suffers from poor structural stability and electronic conductivity. Replacing Mn 4+ ions by relatively larger Sn 4+ ions is regarded as a possible strategy to improve structural stability and thus cycling performance of Li 2 MnO 3 material. However, large difference in ionic radii of Mn 4+ and Sn 4+ ions leads to phase separation of Li 2 MnO 3 and Li 2 SnO 3 during high-temperature synthesis. To prepare solid-solution phase of Li 2 MnO 3 -Li 2 SnO 3 , a buffer agent of Ru 4+ , whose ionic radius is in between that of Mn 4+ and Sn 4+ ions, is introduced to assist the formation of a single solid-solution phase. The results show that the Li 2 RuO 3 -Li 2 MnO 3 -Li 2 SnO 3 ternary system evolves from mixed composite phases into a single solid-solution phase with increasing Ru content. Meanwhile, discharge capacity of this ternary system shows significantly increase at the transformation point which is ascribed to the improvement of Li + /e - transportation kinetics and anionic redox chemistry for solid-solution phase. The role of Mn/Sn molar ratio of Li 2 RuO 3 -Li 2 MnO 3 -Li 2 SnO 3 ternary system has also been studied. It is revealed that higher Sn content benefits cycling stability of the system because Sn 4+ ions with larger sizes could partially block the migration of Mn 4+ and Ru 4+ from transition metal layer to Li layer, thus suppressing structural transformation of the system from layered-to-spinel phase. These findings may enable a new route for exploring ternary or even quaternary lithium-rich cathode materials for LIBs.

  12. A Study on Phase Changes of Heterogeneous Composite Materials

    NASA Astrophysics Data System (ADS)

    Hirasawa, Yoshio; Saito, Akio; Takegoshi, Eisyun

    In this study, a phase change process in heterogeneous composite materials which consist of water and coiled copper wires as conductive solid is investigated by four kinds of typical calculation models : 1) model-1 in which the effective thermal conductivity of the composite material is used, 2) model-2 in which a fin metal acts for many conductive solids, 3) model-3 in which the effective thermal conductivities between nodes are estimated and three-dimensional calculation is performed, 4) model-4 proposed by authors in the previous paper in which effective thermal conductivity is not needed. Consequently, model-1 showed the phase change rate considerably lower than the experimental results. Model-2 gave the larger amount of the phase change rate. Model-3 agreed well with the experiment in the case of small coil diameter and relatively large Vd. Model-4 showed a very well agreement with the experiment in the range of this study.

  13. Mycoestrogen determination in cow milk: Magnetic solid-phase extraction followed by liquid chromatography and tandem mass spectrometry analysis.

    PubMed

    Capriotti, Anna Laura; Cavaliere, Chiara; Foglia, Patrizia; La Barbera, Giorgia; Samperi, Roberto; Ventura, Salvatore; Laganà, Aldo

    2016-12-01

    Recently, magnetic solid-phase extraction has gained interest because it presents various operational advantages over classical solid-phase extraction. Furthermore, magnetic nanoparticles are easy to prepare, and various materials can be used in their synthesis. In the literature, there are only few studies on the determination of mycoestrogens in milk, although their carryover in milk has occurred. In this work, we wanted to develop the first (to the best of our knowledge) magnetic solid-phase extraction protocol for six mycoestrogens from milk, followed by liquid chromatography and tandem mass spectrometry analysis. Magnetic graphitized carbon black was chosen as the adsorbent, as this carbonaceous material, which is very different from the most diffuse graphene and carbon nanotubes, had already shown selectivity towards estrogenic compounds in milk. The graphitized carbon black was decorated with Fe 3 O 4 , which was confirmed by the characterization analyses. A milk deproteinization step was avoided, using only a suitable dilution in phosphate buffer as sample pretreatment. The overall process efficiency ranged between 52 and 102%, whereas the matrix effect considered as signal suppression was below 33% for all the analytes even at the lowest spiking level. The obtained method limits of quantification were below those of other published methods that employ classical solid-phase extraction protocols. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Microwave assisted solid phase extraction for separation preconcentration sulfamethoxazole in wastewater using tyre based activated carbon as solid phase material prior to spectrophotometric determination.

    PubMed

    Mogolodi Dimpe, K; Mpupa, Anele; Nomngongo, Philiswa N

    2018-01-05

    This work was chiefly encouraged by the continuous consumption of antibiotics which eventually pose harmful effects on animals and human beings when present in water systems. In this study, the activated carbon (AC) was used as a solid phase material for the removal of sulfamethoxazole (SMX) in wastewater samples. The microwave assisted solid phase extraction (MASPE) as a sample extraction method was employed to better extract SMX in water samples and finally the analysis of SMX was done by the UV-Vis spectrophotometer. The microwave assisted solid phase extraction method was optimized using a two-level fractional factorial design by evaluating parameters such as pH, mass of adsorbent (MA), extraction time (ET), eluent ratio (ER) and microwave power (MP). Under optimized conditions, the limit of detection (LOD) and limit of quantification (LOQ) were 0.5μgL -1 and 1.7μgL -1 , respectively, and intraday and interday precision expressed in terms of relative standard deviation were >6%.The maximum adsorption capacity was 138mgg -1 for SMX and the adsorbent could be reused eight times. Lastly, the MASPE method was applied for the removal of SMX in wastewater samples collected from a domestic wastewater treatment plant (WWTP) and river water. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Molecularly imprinted polymer/cryogel composites for solid-phase extraction of bisphenol A from river water and wine.

    PubMed

    Baggiani, Claudio; Baravalle, Patrizia; Giovannoli, Cristina; Anfossi, Laura; Giraudi, Gianfranco

    2010-05-01

    Superporous monolithic hydrogels (cryogel monoliths) are elastic, sponge-like materials that can be prepared in an aqueous medium through a cryotropic gelation technique. These monoliths show interesting properties for the development of high-throughput solid-phase extraction supports to treat large volumes of aqueous samples. In this work, a cryogel-supported molecularly imprinted solid-phase extraction approach for the endocrine disruptor bisphenol A (BPA) from river water and wine samples is presented. An imprinted polymer with molecular recognition properties for BPA was prepared in acetonitrile by thermal polymerization of a mixture of 4,4'-dihydroxy-2,2-diphenyl-1,1,1,3,3,3-trifluoropropane as a mimic template of BPA, 4-vinylpyridine and trimethylolpropane trimethacrylate in a molar ratio of 1 + 6 + 6. Fine imprinted particles (<10 microm) were embedded in a poly-acrylamide-co-N,N'-methylenbisacrylamide cryogel obtained by ammonium persulfate-induced cryopolymerization at -18 degrees C. The resulting monolithic gel was evaluated for its use as a sorbent support in an off-line solid-phase extraction approach to recover BPA from dilute aqueous samples with minimum pre-loading work-up. The optimized extraction protocol resulted in a reliable MISPE method suitable to selectively extract and preconcentrate BPA from river water and red wine samples, demonstrating the practical feasibility of cryogel-trapped imprinted polymers as solid-phase extraction materials.

  16. Development of a poly(dimethylacrylamide) based matrix material for solid phase high density peptide array synthesis employing a laser based material transfer

    NASA Astrophysics Data System (ADS)

    Ridder, Barbara; Foertsch, Tobias C.; Welle, Alexander; Mattes, Daniela S.; von Bojnicic-Kninski, Clemens M.; Loeffler, Felix F.; Nesterov-Mueller, Alexander; Meier, Michael A. R.; Breitling, Frank

    2016-12-01

    Poly(dimethylacrylamide) (PDMA) based matrix materials were developed for laser-based in situ solid phase peptide synthesis to produce high density arrays. In this specific array synthesis approach, amino acid derivatives are embedded into a matrix material, serving as a ;solid; solvent material at room temperature. Then, a laser pulse transfers this mixture to the target position on a synthesis slide, where the peptide array is synthesized. Upon heating above the glass transition temperature of the matrix material, it softens, allowing diffusion of the amino acid derivatives to the synthesis surface and serving as a solvent for peptide bond formation. Here, we synthesized PDMA six-arm star polymers, offering the desired matrix material properties, using atom transfer radical polymerization. With the synthesized polymers as matrix material, we structured and synthesized arrays with combinatorial laser transfer. With densities of up to 20,000 peptide spots per cm2, the resolution could be increased compared to the commercially available standard matrix material. Time-of-Flight Secondary Ion Mass Spectrometry experiments revealed the penetration behavior of an amino acid derivative into the prepared acceptor synthesis surface and the effectiveness of the washing protocols.

  17. Heterogeneous fuel for hybrid rocket

    NASA Technical Reports Server (NTRS)

    Stickler, David B. (Inventor)

    1996-01-01

    Heterogeneous fuel compositions suitable for use in hybrid rocket engines and solid-fuel ramjet engines, The compositions include mixtures of a continuous phase, which forms a solid matrix, and a dispersed phase permanently distributed therein. The dispersed phase or the matrix vaporizes (or melts) and disperses into the gas flow much more rapidly than the other, creating depressions, voids and bumps within and on the surface of the remaining bulk material that continuously roughen its surface, This effect substantially enhances heat transfer from the combusting gas flow to the fuel surface, producing a correspondingly high burning rate, The dispersed phase may include solid particles, entrained liquid droplets, or gas-phase voids having dimensions roughly similar to the displacement scale height of the gas-flow boundary layer generated during combustion.

  18. Magnetic graphene oxide modified by imidazole-based ionic liquids for the magnetic-based solid-phase extraction of polysaccharides from brown alga.

    PubMed

    Wang, Xiaoqin; Li, Guizhen; Row, Kyung Ho

    2017-08-01

    Magnetic graphene oxide was modified by four imidazole-based ionic liquids to synthesize materials for the extraction of polysaccharides by magnetic solid-phase extraction. Fucoidan and laminarin were chosen as the representative polysaccharides owing to their excellent pharmaceutical value and availability. Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, and thermogravimetric analysis were applied to characterize the synthesized materials. Single-factor experiments showed that the extraction efficiency of polysaccharides was affected by the amount of ionic liquids for modification, solid-liquid ratio of brown alga and ethanol, the stirring time of brown alga and ionic liquid-modified magnetic graphene oxide materials, and amount of 1-(3-aminopropyl)imidazole chloride modified magnetic graphene oxide materials added to the brown alga sample solution. The results indicated that 1-(3-aminopropyl)imidazole chloride modified magnetic graphene oxide possessed better extraction ability than graphene oxide, magnetic graphene oxide, and other three ionic-liquid-modified magnetic graphene oxide materials. The highest extraction recoveries of fucoidan and laminarin extracted by 1-(3-aminopropyl)imidazole chloride modified magnetic graphene oxide were 93.3 and 87.2%, respectively. In addition, solid materials could be separated and reused easily owing to their magnetic properties. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Potential High-Temperature Shape-Memory-Alloy Actuator Material Identified

    NASA Technical Reports Server (NTRS)

    Noebe, Ronald D.; Gaydosh, Darrell J.; Biles, Tiffany A.; Garg, Anita

    2005-01-01

    Shape-memory alloys are unique "smart materials" that can be used in a wide variety of adaptive or "intelligent" components. Because of a martensitic solid-state phase transformation in these materials, they can display rather unusual mechanical properties including shape-memory behavior. This phenomenon occurs when the material is deformed at low temperatures (below the martensite finish temperature, Mf) and then heated through the martensite-to-austenite phase transformation. As the material is heated to the austenite finish temperature Af, it is able to recover its predeformed shape. If a bias is applied to the material as it tries to recover its original shape, work can be extracted from the shape-memory alloy as it transforms. Therefore, shape-memory alloys are being considered for compact solid-state actuation devices to replace hydraulic, pneumatic, or motor-driven systems.

  20. Long-wave equivalent viscoelastic solids for porous rocks saturated by two-phase fluids

    NASA Astrophysics Data System (ADS)

    Santos, J. E.; Savioli, G. B.

    2018-04-01

    Seismic waves traveling across fluid-saturated poroelastic materials with mesoscopic-scale heterogeneities induce fluid flow and Biot's slow waves generating energy loss and velocity dispersion. Using Biot's equations of motion to model these type of heterogeneities would require extremely fine meshes. We propose a numerical upscaling procedure to determine the complex and frequency dependent P-wave and shear moduli of an effective viscoelastic medium long-wave equivalent to a poroelastic solid saturated by a two-phase fluid. The two-phase fluid is defined in terms of capillary pressure and relative permeability flow functions. The P-wave and shear effective moduli are determined using harmonic compressibility and shear experiments applied on representative samples of the bulk material. Each experiment is associated with a boundary value problem that is solved using the finite element method. Since a poroelastic solid saturated by a two-phase fluid supports the existence of two slow waves, this upscaling procedure allows to analyze their effect on the mesoscopic-loss mechanism in hydrocarbon reservoir formations. Numerical results show that a two-phase Biot medium model predicts higher attenuation than classic Biot models.

  1. Long-wave equivalent viscoelastic solids for porous rocks saturated by two-phase fluids

    NASA Astrophysics Data System (ADS)

    Santos, J. E.; Savioli, G. B.

    2018-07-01

    Seismic waves travelling across fluid-saturated poroelastic materials with mesoscopic-scale heterogeneities induce fluid flow and Biot's slow waves generating energy loss and velocity dispersion. Using Biot's equations of motion to model these type of heterogeneities would require extremely fine meshes. We propose a numerical upscaling procedure to determine the complex and frequency-dependent Pwave and shear moduli of an effective viscoelastic medium long-wave equivalent to a poroelastic solid saturated by a two-phase fluid. The two-phase fluid is defined in terms of capillary pressure and relative permeability flow functions. The Pwave and shear effective moduli are determined using harmonic compressibility and shear experiments applied on representative samples of the bulk material. Each experiment is associated with a boundary value problem that is solved using the finite element method. Since a poroelastic solid saturated by a two-phase fluid supports the existence of two slow waves, this upscaling procedure allows to analyse their effect on the mesoscopic loss mechanism in hydrocarbon reservoir formations. Numerical results show that a two-phase Biot medium model predicts higher attenuation than classic Biot models.

  2. Crystallization features of normal alkanes in confined geometry.

    PubMed

    Su, Yunlan; Liu, Guoming; Xie, Baoquan; Fu, Dongsheng; Wang, Dujin

    2014-01-21

    How polymers crystallize can greatly affect their thermal and mechanical properties, which influence the practical applications of these materials. Polymeric materials, such as block copolymers, graft polymers, and polymer blends, have complex molecular structures. Due to the multiple hierarchical structures and different size domains in polymer systems, confined hard environments for polymer crystallization exist widely in these materials. The confined geometry is closely related to both the phase metastability and lifetime of polymer. This affects the phase miscibility, microphase separation, and crystallization behaviors and determines both the performance of polymer materials and how easily these materials can be processed. Furthermore, the size effect of metastable states needs to be clarified in polymers. However, scientists find it difficult to propose a quantitative formula to describe the transition dynamics of metastable states in these complex systems. Normal alkanes [CnH2n+2, n-alkanes], especially linear saturated hydrocarbons, can provide a well-defined model system for studying the complex crystallization behaviors of polymer materials, surfactants, and lipids. Therefore, a deeper investigation of normal alkane phase behavior in confinement will help scientists to understand the crystalline phase transition and ultimate properties of many polymeric materials, especially polyolefins. In this Account, we provide an in-depth look at the research concerning the confined crystallization behavior of n-alkanes and binary mixtures in microcapsules by our laboratory and others. Since 2006, our group has developed a technique for synthesizing nearly monodispersed n-alkane containing microcapsules with controllable size and surface porous morphology. We applied an in situ polymerization method, using melamine-formaldehyde resin as shell material and nonionic surfactants as emulsifiers. The solid shell of microcapsules can provide a stable three-dimensional (3-D) confining environment. We have studied multiple parameters of these microencapsulated n-alkanes, including surface freezing, metastability of the rotator phase, and the phase separation behaviors of n-alkane mixtures using differential scanning calorimetry (DSC), temperature-dependent X-ray diffraction (XRD), and variable-temperature solid-state nuclear magnetic resonance (NMR). Our investigations revealed new direct evidence for the existence of surface freezing in microencapsulated n-alkanes. By examining the differences among chain packing and nucleation kinetics between bulk alkane solid solutions and their microencapsulated counterparts, we also discovered a mechanism responsible for the formation of a new metastable bulk phase. In addition, we found that confinement suppresses lamellar ordering and longitudinal diffusion, which play an important role in stabilizing the binary n-alkane solid solution in microcapsules. Our work also provided new insights into the phase separation of other mixed system, such as waxes, lipids, and polymer blends in confined geometry. These works provide a profound understanding of the relationship between molecular structure and material properties in the context of crystallization and therefore advance our ability to improve applications incorporating polymeric and molecular materials.

  3. An optoelectronic framework enabled by low-dimensional phase-change films.

    PubMed

    Hosseini, Peiman; Wright, C David; Bhaskaran, Harish

    2014-07-10

    The development of materials whose refractive index can be optically transformed as desired, such as chalcogenide-based phase-change materials, has revolutionized the media and data storage industries by providing inexpensive, high-speed, portable and reliable platforms able to store vast quantities of data. Phase-change materials switch between two solid states--amorphous and crystalline--in response to a stimulus, such as heat, with an associated change in the physical properties of the material, including optical absorption, electrical conductance and Young's modulus. The initial applications of these materials (particularly the germanium antimony tellurium alloy Ge2Sb2Te5) exploited the reversible change in their optical properties in rewritable optical data storage technologies. More recently, the change in their electrical conductivity has also been extensively studied in the development of non-volatile phase-change memories. Here we show that by combining the optical and electronic property modulation of such materials, display and data visualization applications that go beyond data storage can be created. Using extremely thin phase-change materials and transparent conductors, we demonstrate electrically induced stable colour changes in both reflective and semi-transparent modes. Further, we show how a pixelated approach can be used in displays on both rigid and flexible films. This optoelectronic framework using low-dimensional phase-change materials has many likely applications, such as ultrafast, entirely solid-state displays with nanometre-scale pixels, semi-transparent 'smart' glasses, 'smart' contact lenses and artificial retina devices.

  4. Apparatus for the processing of solid mixed waste containing radioactive and hazardous materials

    DOEpatents

    Gotovchikov, Vitaly T.; Ivanov, Alexander V.; Filippov, Eugene A.

    1999-03-16

    Apparatus for the continuous heating and melting of a solid mixed waste bearing radioactive and hazardous materials to form separate metallic, slag and gaseous phases for producing compact forms of the waste material to facilitate disposal includes a copper split water-cooled (cold) crucible as a reaction vessel for receiving the waste material. The waste material is heated by means of the combination oaf plasma torch directed into the open upper portion of the cold crucible and an electromagnetic flux produced by induction coils disposed about the crucible which is transparent to electromagnetic fields. A metallic phase of the waste material is formed in a lower portion of the crucible and is removed in the form of a compact ingot suitable for recycling and further processing. A glass-like, non-metallic slag phase containing radioactive elements is also formed in the crucible and flows out of the open upper portion of the crucible into a slag ingot mold for disposal. The decomposition products of the organic and toxic materials are incinerated and converted to environmentally safe gases in the melter.

  5. Processing of solid mixed waste containing radioactive and hazardous materials

    DOEpatents

    Gotovchikov, Vitaly T.; Ivanov, Alexander V.; Filippov, Eugene A.

    1998-05-12

    Apparatus for the continuous heating and melting of a solid mixed waste bearing radioactive and hazardous materials to form separate metallic, slag and gaseous phases for producing compact forms of the waste material to facilitate disposal includes a copper split water-cooled (cold) crucible as a reaction vessel for receiving the waste material. The waste material is heated by means of the combination of a plasma torch directed into the open upper portion of the cold crucible and an electromagnetic flux produced by induction coils disposed about the crucible which is transparent to electromagnetic fields. A metallic phase of the waste material is formed in a lower portion of the crucible and is removed in the form of a compact ingot suitable for recycling and further processing. A glass-like, non-metallic slag phase containing radioactive elements is also formed in the crucible and flows out of the open upper portion of the crucible into a slag ingot mold for disposal. The decomposition products of the organic and toxic materials are incinerated and converted to environmentally safe gases in the melter.

  6. Apparatus for the processing of solid mixed waste containing radioactive and hazardous materials

    DOEpatents

    Gotovchikov, V.T.; Ivanov, A.V.; Filippov, E.A.

    1999-03-16

    Apparatus for the continuous heating and melting of a solid mixed waste bearing radioactive and hazardous materials to form separate metallic, slag and gaseous phases for producing compact forms of the waste material to facilitate disposal includes a copper split water-cooled (cold) crucible as a reaction vessel for receiving the waste material. The waste material is heated by means of the combination of a plasma torch directed into the open upper portion of the cold crucible and an electromagnetic flux produced by induction coils disposed about the crucible which is transparent to electromagnetic fields. A metallic phase of the waste material is formed in a lower portion of the crucible and is removed in the form of a compact ingot suitable for recycling and further processing. A glass-like, non-metallic slag phase containing radioactive elements is also formed in the crucible and flows out of the open upper portion of the crucible into a slag ingot mold for disposal. The decomposition products of the organic and toxic materials are incinerated and converted to environmentally safe gases in the melter. 6 figs.

  7. Processing of solid mixed waste containing radioactive and hazardous materials

    DOEpatents

    Gotovchikov, V.T.; Ivanov, A.V.; Filippov, E.A.

    1998-05-12

    Apparatus for the continuous heating and melting of a solid mixed waste bearing radioactive and hazardous materials to form separate metallic, slag and gaseous phases for producing compact forms of the waste material to facilitate disposal includes a copper split water-cooled (cold) crucible as a reaction vessel for receiving the waste material. The waste material is heated by means of the combination of a plasma torch directed into the open upper portion of the cold crucible and an electromagnetic flux produced by induction coils disposed about the crucible which is transparent to electromagnetic fields. A metallic phase of the waste material is formed in a lower portion of the crucible and is removed in the form of a compact ingot suitable for recycling and further processing. A glass-like, non-metallic slag phase containing radioactive elements is also formed in the crucible and flows out of the open upper portion of the crucible into a slag ingot mold for disposal. The decomposition products of the organic and toxic materials are incinerated and converted to environmentally safe gases in the melter. 6 figs.

  8. A review of solid-fluid selection options for optical-based measurements in single-phase liquid, two-phase liquid-liquid and multiphase solid-liquid flows

    NASA Astrophysics Data System (ADS)

    Wright, Stuart F.; Zadrazil, Ivan; Markides, Christos N.

    2017-09-01

    Experimental techniques based on optical measurement principles have experienced significant growth in recent decades. They are able to provide detailed information with high-spatiotemporal resolution on important scalar (e.g., temperature, concentration, and phase) and vector (e.g., velocity) fields in single-phase or multiphase flows, as well as interfacial characteristics in the latter, which has been instrumental to step-changes in our fundamental understanding of these flows, and the development and validation of advanced models with ever-improving predictive accuracy and reliability. Relevant techniques rely upon well-established optical methods such as direct photography, laser-induced fluorescence, laser Doppler velocimetry/phase Doppler anemometry, particle image/tracking velocimetry, and variants thereof. The accuracy of the resulting data depends on numerous factors including, importantly, the refractive indices of the solids and liquids used. The best results are obtained when the observational materials have closely matched refractive indices, including test-section walls, liquid phases, and any suspended particles. This paper reviews solid-liquid and solid-liquid-liquid refractive-index-matched systems employed in different fields, e.g., multiphase flows, turbomachinery, bio-fluid flows, with an emphasis on liquid-liquid systems. The refractive indices of various aqueous and organic phases found in the literature span the range 1.330-1.620 and 1.251-1.637, respectively, allowing the identification of appropriate combinations to match selected transparent or translucent plastics/polymers, glasses, or custom materials in single-phase liquid or multiphase liquid-liquid flow systems. In addition, the refractive indices of fluids can be further tuned with the use of additives, which also allows for the matching of important flow similarity parameters such as density and viscosity.

  9. Experimental evidence for an absorbing phase transition underlying yielding of a soft glass

    NASA Astrophysics Data System (ADS)

    Nagamanasa, K. Hima; Gokhale, Shreyas; Sood, A. K.; Ganapathy, Rajesh

    2014-03-01

    A characteristic feature of solids ranging from foams to atomic crystals is the existence of a yield point, which marks the threshold stress beyond which a material undergoes plastic deformation. In hard materials, it is well-known that local yield events occur collectively in the form of intermittent avalanches. The avalanche size distributions exhibit power-law scaling indicating the presence of self-organized criticality. These observations led to predictions of a non-equilibrium phase transition at the yield point. By contrast, for soft solids like gels and dense suspensions, no such predictions exist. In the present work, by combining particle scale imaging with bulk rheology, we provide a direct evidence for a non-equilibrium phase transition governing yielding of an archetypal soft solid - a colloidal glass. The order parameter and the relaxation time exponents revealed that yielding is an absorbing phase transition that belongs to the conserved directed percolation universality class. We also identified a growing length scale associated with clusters of particles with high Debye-Waller factor. Our findings highlight the importance of correlations between local yield events and may well stimulate the development of a unified description of yielding of soft solids.

  10. Nondestructive ultrasonic characterization of engineering materials

    NASA Technical Reports Server (NTRS)

    Salama, K.

    1985-01-01

    The development of an ultrasonic method for the nondestructive characterization of mechanical properties of engineering material is described. The method utilizes the nonlinearity parameter measurement which describes the anharmonic behavior of the solid through measurements of amplitudes of the fundamental and of the generated second harmonic ultrasonic waves. The nonlinearity parameter is also directly related to the acoustoelastic constant of the solid which can be determined by measuring the linear dependence of ultrasonic velocity on stress. A major advantage of measurements of the nonlinearity parameter over that of the acoustoelastic constant is that it may be determined without the application of stress on the material, which makes it more applicable for in-service nondestructive characterization. The relationships between the nonlinearity parameter of second-harmonic generation and the percentage of solid solution phase in engineering materials such as heat treatable aluminum alloys was established. The acoustoelastic constants are measured on these alloys for comparison and confirmation. A linear relationship between the nonlinearity parameter and the volume fraction of second phase precipitates in the alloys is indicated.

  11. Synthesis and structural studies on cerium substituted La0.4Ca0.6MnO3 as solid oxide fuel cell electrode material

    NASA Astrophysics Data System (ADS)

    Singh, Monika; Kumar, Dinesh; Singh, Akhilesh Kumar

    2018-04-01

    For solid oxide fuel cell electrode material, calcium doped lanthanum manganite La0.4Ca0.6MnO3 (LCMO) and cerium-incorporated on Ca-site with composition La0.40Ca0.55Ce0.05MnO3 (LCCMO) were synthesized using most feasible and efficient glycine-nitrate method. The formation of crystalline single phase was confirmed by x-ray diffraction (XRD). The Rietveld analysis reveals that both systems crystallize into orthorhombic crystal structure with Pnma space group. Additionally, 8 mole % Y2O3 stabilized ZrO2 (8YSZ) solid electrolyte was also synthesized using high energy ball mill to check the reaction with electrode materials. It was found that the substitution of Ce+4 cations in LCMO perovskite suppressed formation of undesired insulating CaZrO3 phase.

  12. Electron-beam-irradiation-induced crystallization of amorphous solid phase change materials

    NASA Astrophysics Data System (ADS)

    Zhou, Dong; Wu, Liangcai; Wen, Lin; Ma, Liya; Zhang, Xingyao; Li, Yudong; Guo, Qi; Song, Zhitang

    2018-04-01

    The electron-beam-irradiation-induced crystallization of phase change materials in a nano sized area was studied by in situ transmission electron microscopy and selected area electron diffraction. Amorphous phase change materials changed to a polycrystalline state after being irradiated with a 200 kV electron beam for a long time. The results indicate that the crystallization temperature strongly depends on the difference in the heteronuclear bond enthalpy of the phase change materials. The selected area electron diffraction patterns reveal that Ge2Sb2Te5 is a nucleation-dominated material, when Si2Sb2Te3 and Ti0.5Sb2Te3 are growth-dominated materials.

  13. A novel approach to model the transient behavior of solid-oxide fuel cell stacks

    NASA Astrophysics Data System (ADS)

    Menon, Vikram; Janardhanan, Vinod M.; Tischer, Steffen; Deutschmann, Olaf

    2012-09-01

    This paper presents a novel approach to model the transient behavior of solid-oxide fuel cell (SOFC) stacks in two and three dimensions. A hierarchical model is developed by decoupling the temperature of the solid phase from the fluid phase. The solution of the temperature field is considered as an elliptic problem, while each channel within the stack is modeled as a marching problem. This paper presents the numerical model and cluster algorithm for coupling between the solid phase and fluid phase. For demonstration purposes, results are presented for a stack operated on pre-reformed hydrocarbon fuel. Transient response to load changes is studied by introducing step changes in cell potential and current. Furthermore, the effect of boundary conditions and stack materials on response time and internal temperature distribution is investigated.

  14. Molecularly imprinted solid-phase extraction sorbent for the clean-up of chlorinated phenoxyacids from aqueous samples.

    PubMed

    Baggiani, C; Giovannoli, C; Anfossi, L; Tozzi, C

    2001-12-14

    A molecularly imprinted polymer (MIP) was synthesized using the herbicide 2,4,5-trichlorophenoxyacetic acid as a template, 4-vinylpyridine as an interacting monomer, ethylendimethacrylate as a cross-linker and a methanol-water mixture as a porogen. The binding properties and the selectivity of the polymer towards the template were investigated by frontal and zonal liquid chromatography. The polymer was used as a solid-phase extraction material for the clean-up of the template molecule and some related herbicides (2,4-dichlorophenoxyacetic acid, fenoprop, dichlorprop) from river water samples at a concentration level of ng/ml with quantitative recoveries comparable with those obtained with a traditional C18 reversed-phase column when analyzed by capillary electrophoresis. The results obtained show that the MIP-based approach to the solid-phase extraction is comparable with the more traditional solid-phase extraction with C18 reversed-phase columns in terms of recovery, but it is superior in terms of sample clean-up.

  15. Microscale solid-state thermal diodes enabling ambient temperature thermal circuits for energy applications.

    PubMed

    Wang, Song; Cottrill, Anton L; Kunai, Yuichiro; Toland, Aubrey R; Liu, Pingwei; Wang, Wen-Jun; Strano, Michael S

    2017-05-24

    Thermal diodes, or devices that transport thermal energy asymmetrically, analogous to electrical diodes, hold promise for thermal energy harvesting and conservation, as well as for phononics or information processing. The junction of a phase change material and phase invariant material can form a thermal diode; however, there are limited constituent materials available for a given target temperature, particularly near ambient. In this work, we demonstrate that a micro and nanoporous polystyrene foam can house a paraffin-based phase change material, fused to PMMA, to produce mechanically robust, solid-state thermal diodes capable of ambient operation with Young's moduli larger than 11.5 MPa and 55.2 MPa above and below the melting transition point, respectively. Moreover, the composites show significant changes in thermal conductivity above and below the melting point of the constituent paraffin and rectification that is well-described by our previous theory and the Maxwell-Eucken model. Maximum thermal rectifications range from 1.18 to 1.34. We show that such devices perform reliably enough to operate in thermal diode bridges, dynamic thermal circuits capable of transforming oscillating temperature inputs into single polarity temperature differences - analogous to an electrical diode bridge with widespread implications for transient thermal energy harvesting and conservation. Overall, our approach yields mechanically robust, solid-state thermal diodes capable of engineering design from a mathematical model of phase change and thermal transport, with implications for energy harvesting.

  16. Static SPME sampling of VOCs emitted from indoor building materials: prediction of calibration curves of single compounds for two different emission cells.

    PubMed

    Mocho, Pierre; Desauziers, Valérie

    2011-05-01

    Solid-phase microextraction (SPME) is a powerful technique, easy to implement for on-site static sampling of indoor VOCs emitted by building materials. However, a major constraint lies in the establishment of calibration curves which requires complex generation of standard atmospheres. Thus, the purpose of this paper is to propose a model to predict adsorption kinetics (i.e., calibration curves) of four model VOCs. The model is based on Fick's laws for the gas phase and on the equilibrium or the solid diffusion model for the adsorptive phase. Two samplers (the FLEC® and a home-made cylindrical emission cell), coupled to SPME for static sampling of material emissions, were studied. A good agreement between modeling and experimental data is observed and results show the influence of sampling rate on mass transfer mode in function of sample volume. The equilibrium model is adapted to quite large volume sampler (cylindrical cell) while the solid diffusion model is dedicated to small volume sampler (FLEC®). The limiting steps of mass transfer are the diffusion in gas phase for the cylindrical cell and the pore surface diffusion for the FLEC®. In the future, this modeling approach could be a useful tool for time-saving development of SPME to study building material emission in static mode sampling.

  17. High energy density physics effects predicted in simulations of the CERN HiRadMat beam-target interaction experiments

    NASA Astrophysics Data System (ADS)

    Tahir, N. A.; Burkart, F.; Schmidt, R.; Shutov, A.; Wollmann, D.; Piriz, A. R.

    2016-12-01

    Experiments have been done at the CERN HiRadMat (High Radiation to Materials) facility in which large cylindrical copper targets were irradiated with 440 GeV proton beam generated by the Super Proton Synchrotron (SPS). The primary purpose of these experiments was to confirm the existence of hydrodynamic tunneling of ultra-relativistic protons and their hadronic shower in solid materials, that was predicted by previous numerical simulations. The experimental measurements have shown very good agreement with the simulation results. This provides confidence in our simulations of the interaction of the 7 TeV LHC (Large Hadron Collider) protons and the 50 TeV Future Circular Collider (FCC) protons with solid materials, respectively. This work is important from the machine protection point of view. The numerical simulations have also shown that in the HiRadMat experiments, a significant part of thetarget material is be converted into different phases of High Energy Density (HED) matter, including two-phase solid-liquid mixture, expanded as well as compressed hot liquid phases, two-phase liquid-gas mixture and gaseous state. The HiRadMat facility is therefore a unique ion beam facility worldwide that is currently available for studying the thermophysical properties of HED matter. In the present paper we discuss the numerical simulation results and present a comparison with the experimental measurements.

  18. Drug delivery properties of macroporous polystyrene solid foams.

    PubMed

    Canal, Cristina; Aparicio, Rosa Maria; Vilchez, Alejandro; Esquena, Jordi; García-Celma, Maria José

    2012-01-01

    Polymeric porous foams have been evaluated as possible new pharmaceutical dosage forms. These materials were obtained by polymerization in the continuous phase of highly concentrated emulsions prepared by the phase inversion temperature method. Their porosity, specific surface and surface topography were characterized, and the incorporation and release of active principles was studied using ketoprofen as model lipophilic molecule. Solid foams with very high pore volume, mainly inside macropores, were obtained by this method. The pore morphology of the materials was characterized, and very rough topography was observed, which contributed to their nearly superhydrophobic properties. These solid foams could be used as delivery systems for active principles with pharmaceutical interest, and in the present work ketoprofen was used as a model lipophilic molecule. Drug incorporation and release was studied from solid foam disks, using different concentrations of the loading solutions, achieving a delayed release with short lag-time.

  19. Effect of transition dipole phase on high-order-harmonic generation in solid materials

    NASA Astrophysics Data System (ADS)

    Jiang, Shicheng; Wei, Hui; Chen, Jigen; Yu, Chao; Lu, Ruifeng; Lin, C. D.

    2017-11-01

    High-order harmonic spectra from solid materials driven by single-color multicycle laser fields sometimes contain even harmonics. In this work we attribute the appearance of even harmonics to the nonzero transition dipole phase (TDP) when the solid system has broken symmetry. By calculating the harmonic efficiency from graphene and gapped graphene by using the semiconductor Bloch equations under the tight-binding approximation, we demonstrate the role of the TDP, which has been ignored for a long time. When the crystal has inversion symmetry, or reflection symmetry with the symmetry plane perpendicular to the laser polarization direction, the TDP can be neglected. Without such symmetry, however, the TDP will lead to the appearance of even harmonics. We further show that the TDP is sensitive to the crystal geometry. To extract the structure information from the harmonic spectra of a solid the TDP cannot be ignored.

  20. Phase equilibrium modeling for high temperature metallization on GaAs solar cells

    NASA Technical Reports Server (NTRS)

    Chung, M. A.; Davison, J. E.; Smith, S. R.

    1991-01-01

    Recent trends in performance specifications and functional requirements have brought about the need for high temperature metallization technology to be developed for survivable DOD space systems and to enhance solar cell reliability. The temperature constitution phase diagrams of selected binary and ternary systems were reviewed to determine the temperature and type of phase transformation present in the alloy systems. Of paramount interest are the liquid-solid and solid-solid transformations. Data are being utilized to aid in the selection of electrical contact materials to gallium arsenide solar cells. Published data on the phase diagrams for binary systems is readily available. However, information for ternary systems is limited. A computer model is being developed which will enable the phase equilibrium predictions for ternary systems where experimental data is lacking.

  1. Separation and purification of thymopentin with molecular imprinting membrane by solid phase extraction disks.

    PubMed

    Wang, Chaoli; Hu, Xiaoling; Guan, Ping; Wu, Danfeng; Qian, Liwei; Li, Ji; Song, Renyuan

    2015-01-01

    The synthesis and performance of molecularly imprinted membranes (MIMs) as a solid phase extraction packing materials for the separation and purification of thymopentin from crude samples was described. In order to increase structural selectivity and imprinting efficiency, surface-initiated ATRP and ionic liquid (1-vinyl-3-ethyl acetate imidazolium chloride) were used to prepare molecularly imprinting membranes. The results demonstrated that solid phase extraction disks stuffed by MIMs with ionic liquids as functional monomer demonstrated high isolation and purification of performance to the thymopentin. The molecular recognition of thymopentin was analyzed by using molecular modeling software. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Microwavable thermal energy storage material

    DOEpatents

    Salyer, I.O.

    1998-09-08

    A microwavable thermal energy storage material is provided which includes a mixture of a phase change material and silica, and a carbon black additive in the form of a conformable dry powder of phase change material/silica/carbon black, or solid pellets, films, fibers, moldings or strands of phase change material/high density polyethylene/ethylene vinyl acetate/silica/carbon black which allows the phase change material to be rapidly heated in a microwave oven. The carbon black additive, which is preferably an electrically conductive carbon black, may be added in low concentrations of from 0.5 to 15% by weight, and may be used to tailor the heating times of the phase change material as desired. The microwavable thermal energy storage material can be used in food serving applications such as tableware items or pizza warmers, and in medical wraps and garments. 3 figs.

  3. Microwavable thermal energy storage material

    DOEpatents

    Salyer, Ival O.

    1998-09-08

    A microwavable thermal energy storage material is provided which includes a mixture of a phase change material and silica, and a carbon black additive in the form of a conformable dry powder of phase change material/silica/carbon black, or solid pellets, films, fibers, moldings or strands of phase change material/high density polyethylene/ethylene-vinyl acetate/silica/carbon black which allows the phase change material to be rapidly heated in a microwave oven. The carbon black additive, which is preferably an electrically conductive carbon black, may be added in low concentrations of from 0.5 to 15% by weight, and may be used to tailor the heating times of the phase change material as desired. The microwavable thermal energy storage material can be used in food serving applications such as tableware items or pizza warmers, and in medical wraps and garments.

  4. Ionic liquid-modified materials for solid-phase extraction and separation: a review.

    PubMed

    Vidal, Lorena; Riekkola, Marja-Liisa; Canals, Antonio

    2012-02-17

    In recent years, materials science has propelled to the research forefront. Ionic liquids with unique and fascinating properties have also left their footprints to the developments of materials science during the last years. In this review we highlight some of their recent advances and provide an overview at the current status of ionic liquid-modified materials applied in solid-phase extraction, liquid and gas chromatography and capillary electrochromatography with reference to recent applications. In addition, the potential of ionic liquids in the modification of capillary inner wall in capillary electrophoresis is demonstrated. The main target material modified with ionic liquids is silica, but polymers and monoliths have recently joined the studies. Although imidazolium is still clearly the most commonly used ionic liquid for the covalently modification of materials, the exploitation of pyridinium and phosphonium will most probably increase in the future. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Development of SiAlON materials

    NASA Technical Reports Server (NTRS)

    Layden, G. K.

    1977-01-01

    Cold pressing and sintering techniques were used to produce ceramic bodies in which the major phase was beta prime Si3-Al-O-N4 solid solution. A variety of foreign oxides were used to promote liquid phase sintering, and this resulted in the incorporation of additional solid phases in the ceramic bodies which controlled elevated temperature properties. None of the bodies studied to date exhibited both adequate high temperature mechanical properties and oxidation resistance. Criteria are suggested to guide the formulation of bodies with improved high temperature properties.

  6. CO2-Doped Diamond: A Potential Solid-State CO2 Laser Material?

    NASA Technical Reports Server (NTRS)

    Tratt, D.

    1994-01-01

    This paper describes a novel concept for a solid-state CO subscript 2 laser medium which, by eschewing the gas-phase approach, may offer prospects for a compact, robust 9 - 11 (micro)m coherent source, coupled with the potentially superior frequency stability characteristics afforded by monolithic solid-state construction.

  7. Solid State NMR Studies of the Aluminum Hydride Phases

    NASA Technical Reports Server (NTRS)

    Hwang, Son-Jong; Bowman, R. C., Jr.; Graetz, Jason; Reilly, J. J.

    2006-01-01

    Several solid state NMR techniques including magic-angle-spinning (MAS) and multiple-quantum (MQ) MAS experiments have been used to characterize various AlH3 samples. MAS-NMR spectra for the 1H and 27Al nuclei have been obtained on a variety of AlH3 samples that include the (beta)- and (gamma)- phases as well as the most stable (alpha)-phase. While the dominant components in these NMR spectra correspond to the aluminum hydride phases, other species were found that include Al metal, molecular hydrogen (H2), as well as peaks that can be assigned to Al-O species in different configurations. The occurrence and concentration of these extraneous components are dependent upon the initial AlH3 phase composition and preparation procedures. Both the (beta)-AlH3 and (gamma)-AlH3 phases were found to generate substantial amounts of Al metal when the materials were stored at room temperature while the (alpha)-phase materials do not exhibit these changes.

  8. Identification and quantification of odours from oxobiodegradable polyethylene oxidised under a free radical flow by headspace solid-phase microextraction followed by gas chromatography-olfactometry-mass spectrometry.

    PubMed

    Wrona, Magdalena; Vera, Paula; Pezo, Davinson; Nerín, Cristina

    2017-09-01

    Recently oxobiodegradable polyethylene gained popularity as food packaging material due to its potential to reduce polymer waste. However, this type of material can release after its oxidation off-odour compounds that affect the organoleptic properties of packaged food. Odour compounds released from both polyethylene and oxobiodegradable polyethylene before and after oxidation under a free radicals flow were investigated after 1 day, 2 days and 3 days of oxidation. The samples were analysed using headspace solid phase microextraction followed by gas chromatography-mass spectrometry and headspace solid phase microextraction coupled to gas chromatography-olfactometry-mass spectrometry. Sixty-two different odorous compounds were identified. 4-methylthio-2-butanone (fruit), nonanal (fat) and 3,6-nonadienal (fat) were present in different materials before oxidation. Multiple headspace-solid phase microextraction has been used to quantify all analytes. The most abundant compound was (Z)-3-hexenyl hexanoate with a concentration range between 1.5791±0.1387µg/g and 4.8181±0.3123µg/g. Compounds such as 2-dodecenal, 2-octenal, 2-pentanol, 3-nonenal, 3,6-nonadienal, ethyl 3-methylbutanoate, ethyl octenoate, hexanone, isopropyl hexanoate, octanal were below their LOD evaluated using MS detector; however, they were detected by gas chromatography-olfactometry. The minimum LOD and LOQ were 0.011µg/g and 0.036µg/g, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Interface-Driven Phenomena in Solids: Thermodynamics, Kinetics and Chemistry

    DOE PAGES

    Abdeljawad, Fadi; Foiles, Stephen M.

    2016-05-04

    The study of materials interfaces dates back over a century. In solid systems and from an engineering perspective, free surfaces and internal (grain and/or phase) boundaries influence a wide range of properties, such as thermal, electrical and optical transport, and mechanical ones. The properties and the role of interfaces has been discussed extensively in various reviews such as by Sutton and Balluffi. As the characteristic feature size of a materials system (i.e., grain size) is decreased to the nanometer scale, interface-driven physics is expected to dominate due to the increased density of such planar defects. Moreover, interfacial attributes, thermodynamics, andmore » mobility play a key role in phase transformations, such as solidification dynamics and structural transitions in solids, and in homogenization and microstructural evolution processes, such as grain growth, coarsening, and recrystallization. In summary, the set of articles published in this special topic titled: “Interface-Driven Phenomena in Solids: Thermodynamics, Kinetics and Chemistry” covers topics related to microstructure evolution, segregation/adsorption phenomena and interface interactions with other materials defects.« less

  10. Interface-Driven Phenomena in Solids: Thermodynamics, Kinetics and Chemistry

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Abdeljawad, Fadi; Foiles, Stephen M.

    The study of materials interfaces dates back over a century. In solid systems and from an engineering perspective, free surfaces and internal (grain and/or phase) boundaries influence a wide range of properties, such as thermal, electrical and optical transport, and mechanical ones. The properties and the role of interfaces has been discussed extensively in various reviews such as by Sutton and Balluffi. As the characteristic feature size of a materials system (i.e., grain size) is decreased to the nanometer scale, interface-driven physics is expected to dominate due to the increased density of such planar defects. Moreover, interfacial attributes, thermodynamics, andmore » mobility play a key role in phase transformations, such as solidification dynamics and structural transitions in solids, and in homogenization and microstructural evolution processes, such as grain growth, coarsening, and recrystallization. In summary, the set of articles published in this special topic titled: “Interface-Driven Phenomena in Solids: Thermodynamics, Kinetics and Chemistry” covers topics related to microstructure evolution, segregation/adsorption phenomena and interface interactions with other materials defects.« less

  11. A green synthesis of a layered titanate, potassium lithium titanate; lower temperature solid-state reaction and improved materials performance

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ogawa, Makoto, E-mail: waseda.ogawa@gmail.com; Department of Earth Sciences, Waseda University, 1-6-1 Nishiwaseda, Shinjuku-ku, Tokyo 169-8050; Morita, Masashi, E-mail: m-masashi@y.akane.waseda.jp

    2013-10-15

    A layered titanate, potassium lithium titanate, with the size range from 0.1 to 30 µm was prepared to show the effects of the particle size on the materials performance. The potassium lithium titanate was prepared by solid-state reaction as reported previously, where the reaction temperature was varied. The reported temperature for the titanate preparation was higher than 800 °C, though 600 °C is good enough to obtain single-phase potassium lithium titanate. The lower temperature synthesis is cost effective and the product exhibit better performance as photocatalysts due to surface reactivity. - Graphical abstract: Finite particle of a layered titanate, potassiummore » lithium titanate, was prepared by solid-state reaction at lower temperature to show modified materials performance. Display Omitted - Highlights: • Potassium lithium titanate was prepared by solid-state reaction. • Lower temperature reaction resulted in smaller sized particles of titanate. • 600 °C was good enough to obtain single phased potassium lithium titanate. • The product exhibited better performance as photocatalyst.« less

  12. In operando spectroscopic studies of high temperature electrocatalysts used for energy conversion

    NASA Astrophysics Data System (ADS)

    McIntyre, Melissa Dawn

    Solid-state electrochemical cells are efficient energy conversion devices that can be used for clean energy production or for removing air pollutants from exhaust gas emitted by combustion processes. For example, solid oxide fuel cells generate electricity with low emissions from a variety of fuel sources; solid oxide electrolysis cells produce zero-emission H2 fuel; and solid-state DeNOx cells remove NOx gases from diesel exhaust. In order to maintain high conversion efficiencies, these systems typically operate at temperatures ≥ 500°C. The high operating temperatures, however, accelerate chemical and mechanical cell degradation. To improve device durability, a mechanistic understanding of the surface chemistry occurring at the cell electrodes (anode and cathode) is critical in terms of refining cell design, material selection and operation protocols. The studies presented herein utilized in operando Raman spectroscopy coupled with electrochemical measurements to directly correlate molecular/material changes with device performance in solid oxide cells under various operating conditions. Because excessive carbon accumulation with carbon-based fuels destroys anodes, the first three studies investigated strategies for mitigating carbon accumulation on Ni cermet anodes. Results from the first two studies showed that low amounts of solid carbon stabilized the electrical output and improved performance of solid oxide fuel cells operating with syn-gas (H 2/CO fuel mixture). The third study revealed that infiltrating anodes with Sn or BaO suppressed carbon accumulation with CH4 fuel and that H2O was the most effective reforming agent facilitating carbon removal. The last two studies explored how secondary phases formed in traditional solid oxide cell materials doped with metal oxides improve electrochemical performance. Results from the fourth study suggest that the mixed ion-electron conducting Zr5Ti7O24 secondary phase can expand the electrochemically active region and increase electrochemical activity in cermet electrodes. The final study of lanthanum strontium manganite cathodes infiltrated with BaO revealed the reversible decomposition/formation of a Ba3Mn2O8 secondary phase under applied potentials and proposed mechanisms for the enhanced electrocatalytic oxygen reduction associated with this compound under polarizing conditions. Collectively, these studies demonstrate that mechanistic information obtained from molecular/material specific techniques coupled with electrochemical measurements can be used to help optimize materials and operating conditions in solid-state electrochemical cells.

  13. Thermodynamic Investigation of the Effect of Interface Curvature on the Solid-Liquid Equilibrium and Eutectic Point of Binary Mixtures.

    PubMed

    Liu, Fanghui; Zargarzadeh, Leila; Chung, Hyun-Joong; Elliott, Janet A W

    2017-10-12

    Thermodynamic phase behavior is affected by curved interfaces in micro- and nanoscale systems. For example, capillary freezing point depression is associated with the pressure difference between the solid and liquid phases caused by interface curvature. In this study, the thermal, mechanical, and chemical equilibrium conditions are derived for binary solid-liquid equilibrium with a curved solid-liquid interface due to confinement in a capillary. This derivation shows the equivalence of the most general forms of the Gibbs-Thomson and Ostwald-Freundlich equations. As an example, the effect of curvature on solid-liquid equilibrium is explained quantitatively for the water/glycerol system. Considering the effect of a curved solid-liquid interface, a complete solid-liquid phase diagram is developed over a range of concentrations for the water/glycerol system (including the freezing of pure water or precipitation of pure glycerol depending on the concentration of the solution). This phase diagram is compared with the traditional phase diagram in which the assumption of a flat solid-liquid interface is made. We show the extent to which nanoscale interface curvature can affect the composition-dependent freezing and precipitating processes, as well as the change in the eutectic point temperature and concentration with interface curvature. Understanding the effect of curvature on solid-liquid equilibrium in nanoscale capillaries has applications in the food industry, soil science, cryobiology, nanoporous materials, and various nanoscience fields.

  14. Polysaccharide-derived mesoporous materials (Starbon®) for sustainable separation of complex mixtures.

    PubMed

    Zuin, Vânia G; Budarin, Vitaliy L; De Bruyn, Mario; Shuttleworth, Peter S; Hunt, Andrew J; Pluciennik, Camille; Borisova, Aleksandra; Dodson, Jennifer; Parker, Helen L; Clark, James H

    2017-09-21

    The recovery and separation of high value and low volume extractives are a considerable challenge for the commercial realisation of zero-waste biorefineries. Using solid-phase extractions (SPE) based on sustainable sorbents is a promising method to enable efficient, green and selective separation of these complex extractive mixtures. Mesoporous carbonaceous solids derived from renewable polysaccharides are ideal stationary phases due to their tuneable functionality and surface structure. In this study, the structure-separation relationships of thirteen polysaccharide-derived mesoporous materials and two modified types as sorbents for ten naturally-occurring bioactive phenolic compounds were investigated. For the first time, a comprehensive statistical analysis of the key molecular and surface properties influencing the recovery of these species was carried out. The obtained results show the possibility of developing tailored materials for purification, separation or extraction, depending on the molecular composition of the analyte. The wide versatility and application span of these polysaccharide-derived mesoporous materials offer new sustainable and inexpensive alternatives to traditional silica-based stationary phases.

  15. Role of phase instabilities in the early response of bulk fused silica during laser-induced breakdown

    NASA Astrophysics Data System (ADS)

    Demange, P.; Negres, R. A.; Raman, R. N.; Colvin, J. D.; Demos, S. G.

    2011-08-01

    We report on the experimental and hydrocode modeling investigation of the early material response to localized energy deposition via nanosecond laser pulses in bulk fused silica. A time-resolved microscope system was used to acquire transient images with adequate spatial and temporal resolution to resolve the material behavior from the onset of the process. These images revealed a high-pressure shock front propagating at twice the speed of sound at ambient conditions and bounding a region of modified material at delays up to one nanosecond. Hydrocode simulations matching the experimental conditions were also performed and indicated initial pressures of ˜40 GPa and temperatures of ˜1 eV at the absorption region. Both the simulations and the image data show a clear boundary between distinct material phases, a hot plasma and solid silica, with a suggestion that growth of perturbations at the Rayleigh-Taylor unstable interface between the two phases is the seed mechanism for the growth of cracks into the stressed solid.

  16. On the formation of molecules and solid-state compounds from the AGB to the PN phases

    NASA Astrophysics Data System (ADS)

    García-Hernández, D. A.; Manchado, A.

    2016-07-01

    During the asymptoyic giant branch (AGB) phase, different elements are dredge- up to the stellar surface depending on progenitor mass and metallicity. When the mass loss increases at the end of the AGB, a circumstellar dust shell is formed, where different (C-rich or O-rich) molecules and solid-state compounds are formed. These are further processed in the transition phase between AGB stars and planetary nebulae (PNe) to create more complex organic molecules and inorganic solid-state compounds (e.g., polycyclic aromatic hydrocarbons, fullerenes, and graphene precursors in C-rich environments and oxides and crystalline silicates in O-rich ones). We present an observational review of the different molecules and solid-state materials that are formed from the AGB to the PN phases. We focus on the formation routes of complex fullerene (and fullerene-based) molecules as well as on the level of dust processing depending on metallicity.

  17. Multi-layer coatings for bipolar rechargeable batteries with enhanced terminal voltage

    DOEpatents

    Farmer, Joseph C.; Kaschmitter, James; Pierce, Steve

    2017-06-06

    A method for producing a multi-layer bipolar coated cell according to one embodiment includes applying a first active cathode material above a substrate to form a first cathode; applying a first solid-phase ionically-conductive electrolyte material above the first cathode to form a first electrode separation layer; applying a first active anode material above the first electrode separation layer to form a first anode; applying an electrically conductive barrier layer above the first anode; applying a second active cathode material above the anode material to form a second cathode; applying a second solid-phase ionically-conductive electrolyte material above the second cathode to form a second electrode separation layer; applying a second active anode material above the second electrode separation layer to form a second anode; and applying a metal material above the second anode to form a metal coating section. In another embodiment, the anode is formed prior to the cathode. Cells are also disclosed.

  18. Melting along the Hugoniot and solid phase transition for Sn via sound velocity measurements

    NASA Astrophysics Data System (ADS)

    Song, Ping; Cai, Ling-cang; Tao, Tian-jiong; Yuan, Shuai; Chen, Hong; Huang, Jin; Zhao, Xin-wen; Wang, Xue-jun

    2016-11-01

    It is very important to determine the phase boundaries for materials with complex crystalline phase structures to construct their corresponding multi-phase equation of state. By measuring the sound velocity of Sn with different porosities, different shock-induced melting pressures along the solid-liquid phase boundary could be obtained. The incipient shock-induced melting of porous Sn samples with two different porosities occurred at a pressure of about 49.1 GPa for a porosity of 1.01 and 45.6 GPa for a porosity of 1.02, based on measurements of the sound velocity. The incipient shock-induced melting pressure of solid Sn was revised to 58.1 GPa using supplemental measurements of the sound velocity. Trivially, pores in Sn decreased the shock-induced melting pressure. Based on the measured longitudinal sound velocity data, a refined solid phase transition and the Hugoniot temperature-pressure curve's trend are discussed. No bcc phase transition occurs along the Hugoniot for porous Sn; further investigation is required to understand the implications of this finding.

  19. Study of Ti 4+ substitution in ZrW 2O 8 negative thermal expansion materials

    NASA Astrophysics Data System (ADS)

    De Buysser, Klaartje; Van Driessche, Isabel; Putte, Bart Vande; Schaubroeck, Joseph; Hoste, Serge

    2007-08-01

    Powder XRD-analysis and thermo-mechanical analysis on sintered TiO 2-WO 3-ZrO 2 mixtures revealed the formation of Zr 1-xTi xW 2O 8 solid solutions. A noticeable decrease in unit cell parameter ' a' and in the order-disorder transition temperature could be seen in the case of Zr 1-xTi xW 2O 8 solid solutions. Studies performed on other ZrW 2O 8 solid solutions have attributed an increase in phase transition temperature to a decrease in free lattice volume, whereas a decrease in phase transition temperature was suggested to be due to the presence of a more disordered state. Our studies indicate that the phase transition temperature in our materials is strongly influenced by the bond dissociation energy of the substituting ion-oxygen bond. A decrease in bond strength may compensate for the effect of a decrease in lattice free volume, lowering the phase transition temperature as the degree of substitution by Ti 4+ increases. This hypothesis is proved by differential scanning calorimetry.

  20. Designing, Describing and Disseminating New Materials by using the Network Topology Approach.

    PubMed

    Öhrström, Lars

    2016-09-19

    This Concept article describes how network topology analysis is applied to different fields of solid-state chemistry. Its usefulness is demonstrated by examples from metal-organic frameworks, group 14 allotropes and related compounds, ice polymorphs, zeolites, supramolecular (organic) solid-state chemistry, Zintl phases, and cathode materials for Li-ion batteries. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Modeling the Capillary Pressure for the Migration of the Liquid Phase in Granular Solid-Liquid-Vapor Systems: Application to the Control of the Composition Profile in W-Cu FGM Materials

    NASA Astrophysics Data System (ADS)

    Missiaen, Jean-Michel; Raharijaona, Jean-Joël; Delannay, Francis

    2016-11-01

    A model is developed to compute the capillary pressure for the migration of the liquid phase out or into a uniform solid-liquid-vapor system. The capillary pressure is defined as the reduction of the overall interface energy per volume increment of the transferred fluid phase. The model takes into account the particle size of the solid particle aggregate, the packing configuration (coordination number, porosity), the volume fractions of the different phases, and the values of the interface energies in the system. The model is used for analyzing the stability of the composition profile during processing of W-Cu functionally graded materials combining a composition gradient with a particle size gradient. The migration pressure is computed with the model in two stages: (1) just after the melting of copper, i.e., when sintering and shape accommodation of the W particle aggregate can still be neglected and (2) at high temperature, when the system is close to full density with equilibrium particle shape. The model predicts well the different stages of liquid-phase migration observed experimentally.

  2. Hydrothermal carbonization of food waste and associated packaging materials for energy source generation.

    PubMed

    Li, Liang; Diederick, Ryan; Flora, Joseph R V; Berge, Nicole D

    2013-11-01

    Hydrothermal carbonization (HTC) is a thermal conversion technique that converts food wastes and associated packaging materials to a valuable, energy-rich resource. Food waste collected from local restaurants was carbonized over time at different temperatures (225, 250 and 275°C) and solids concentrations to determine how process conditions influence carbonization product properties and composition. Experiments were also conducted to determine the influence of packaging material on food waste carbonization. Results indicate the majority of initial carbon remains integrated within the solid-phase at the solids concentrations and reaction temperatures evaluated. Initial solids concentration influences carbon distribution because of increased compound solubilization, while changes in reaction temperature imparted little change on carbon distribution. The presence of packaging materials significantly influences the energy content of the recovered solids. As the proportion of packaging materials increase, the energy content of recovered solids decreases because of the low energetic retention associated with the packaging materials. HTC results in net positive energy balances at all conditions, except at a 5% (dry wt.) solids concentration. Carbonization of food waste and associated packaging materials also results in net positive balances, but energy needs for solids post-processing are significant. Advantages associated with carbonization are not fully realized when only evaluating process energetics. A more detailed life cycle assessment is needed for a more complete comparison of processes. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Containerless Liquid-Phase Processing of Ceramic Materials

    NASA Technical Reports Server (NTRS)

    Weber, J. K. Richard (Principal Investigator); Nordine, Paul C.

    1996-01-01

    The present project builds on the results of research supported under a previous NASA grant to investigate containerless liquid-phase processing of molten ceramic materials. The research used an aero-acoustic levitator in combination with cw CO2 laser beam heating to achieve containerless melting, superheating, undercooling, and solidification of poorly-conducting solids and liquids. Experiments were performed on aluminum oxide, binary aluminum oxide-silicon dioxide materials, and oxide superconductors.

  4. Disorder-induced stiffness degradation of highly disordered porous materials

    NASA Astrophysics Data System (ADS)

    Laubie, Hadrien; Monfared, Siavash; Radjaï, Farhang; Pellenq, Roland; Ulm, Franz-Josef

    2017-09-01

    The effective mechanical behavior of multiphase solid materials is generally modeled by means of homogenization techniques that account for phase volume fractions and elastic moduli without considering the spatial distribution of the different phases. By means of extensive numerical simulations of randomly generated porous materials using the lattice element method, the role of local textural properties on the effective elastic properties of disordered porous materials is investigated and compared with different continuum micromechanics-based models. It is found that the pronounced disorder-induced stiffness degradation originates from stress concentrations around pore clusters in highly disordered porous materials. We identify a single disorder parameter, φsa, which combines a measure of the spatial disorder of pores (the clustering index, sa) with the pore volume fraction (the porosity, φ) to scale the disorder-induced stiffness degradation. Thus, we conclude that the classical continuum micromechanics models with one spherical pore phase, due to their underlying homogeneity assumption fall short of addressing the clustering effect, unless additional texture information is introduced, e.g. in form of the shift of the percolation threshold with disorder, or other functional relations between volume fractions and spatial disorder; as illustrated herein for a differential scheme model representative of a two-phase (solid-pore) composite model material.

  5. Tunable Bragg filters with a phase transition material defect layer

    DOE PAGES

    Wang, Xi; Gong, Zilun; Dong, Kaichen; ...

    2016-01-01

    We propose an all-solid-state tunable Bragg filter with a phase transition material as the defect layer. Bragg filters based on a vanadium dioxide defect layer sandwiched between silicon dioxide/titanium dioxide Bragg gratings are experimentally demonstrated. Temperature dependent reflection spectroscopy shows the dynamic tunability and hysteresis properties of the Bragg filter. Temperature dependent Raman spectroscopy reveals the connection between the tunability and the phase transition of the vanadium dioxide defect layer. This work paves a new avenue in tunable Bragg filter designs and promises more applications by combining phase transition materials and optical cavities.

  6. Tunable Bragg filters with a phase transition material defect layer

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wang, Xi; Gong, Zilun; Dong, Kaichen

    We propose an all-solid-state tunable Bragg filter with a phase transition material as the defect layer. Bragg filters based on a vanadium dioxide defect layer sandwiched between silicon dioxide/titanium dioxide Bragg gratings are experimentally demonstrated. Temperature dependent reflection spectroscopy shows the dynamic tunability and hysteresis properties of the Bragg filter. Temperature dependent Raman spectroscopy reveals the connection between the tunability and the phase transition of the vanadium dioxide defect layer. This work paves a new avenue in tunable Bragg filter designs and promises more applications by combining phase transition materials and optical cavities.

  7. Investigation of fragrance stability used in the formulation of cosmetic and hygienic products using headspace solid-phase microextraction by nanostructured materials followed by gas chromatography with mass spectrometry.

    PubMed

    Masoum, Saeed; Gholami, Ali; Ghaheri, Salehe; Bouveresse, Delphine Jouan-Rimbaud; Cordella, Christophe B Y; Rutledge, Douglas N

    2016-07-01

    A new composite coating of polypyrrole and sodium lauryl ether sulfate was electrochemically prepared on a stainless-steel wire using cyclic voltammetry. The application and performance of the fiber was evaluated for the headspace solid-phase microextraction of a fragrance in aqueous bleach samples followed by gas chromatography combined with mass spectrometry to assess the fragrance stability in this kind of household cleaning product. To obtain a stable and efficient composite coating, parameters related to the coating process such as scan rate and numbers of cycles were optimized using a central composite design. In addition, the effects of various parameters on the extraction efficiency of the headspace solid-phase microextraction process such as extraction temperature and time, ionic strength, sample volume, and stirring rate were investigated by experimental design methods using Plackett-Burman and Doehlert designs. The optimum values of 53°C and 28 min for sample temperature and time, respectively, were found through response surface methodology. Results show that the combination of polypyrrole and sodium lauryl ether sulfate in a composite form presents desirable opportunities to produce new materials to study fragrance stability by headspace solid-phase microextraction. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Magnetic dispersive solid-phase extraction based on modified magnetic nanoparticles for the detection of cocaine and cocaine metabolites in human urine by high-performance liquid chromatography-mass spectrometry.

    PubMed

    Yang, Feiyu; Zou, Yun; Ni, Chunfang; Wang, Rong; Wu, Min; Liang, Chen; Zhang, Jiabin; Yuan, Xiaoliang; Liu, Wenbin

    2017-11-01

    An easy-to-handle magnetic dispersive solid-phase extraction procedure was developed for preconcentration and extraction of cocaine and cocaine metabolites in human urine. Divinyl benzene and vinyl pyrrolidone functionalized silanized Fe 3 O 4 nanoparticles were synthesized and used as adsorbents in this procedure. Scanning electron microscopy, vibrating sample magnetometry, and infrared spectroscopy were employed to characterize the modified adsorbents. A high-performance liquid chromatography with mass spectrometry method for determination of cocaine and its metabolites in human urine sample has been developed with pretreatment of the samples by magnetic dispersive solid-phase extraction. The obtained results demonstrated the higher extraction capacity of the prepared nanoparticles with recoveries between 75.1 to 105.7% and correlation coefficients higher than 0.9971. The limits of detection for the cocaine and cocaine metabolites were 0.09-1.10 ng/mL. The proposed magnetic dispersive solid-phase extraction method provided a rapid, environmentally friendly and magnetic stuff recyclable approach and it was confirmed that the prepared adsorbents material was a kind of highly effective extraction materials for the trace cocaine and cocaine metabolites analyses in human urine. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Murgia, Fabrizio; Antitomaso, Philippe; Stievano, Lorenzo

    The ternary Chevrel phase Cu{sub 2}Mo{sub 6}S{sub 8} was successfully synthetized using a simple and cost-effective solid-state microwave-assisted reaction. While solid-state routes require days of high-temperature treatment under inert atmosphere, highly pure and crystalline Cu{sub 2}Mo{sub 6}S{sub 8} could be obtained in only 400 s from this precursor, the Chevrel binary phase Mo{sub 6}S{sub 8} was then obtained by copper removal through acidic leaching, and was evaluated as a positive electrode material for Mg-battery. The electrochemical performance in half-cell configuration shows reversible capacity exceeding 80 mAh/g, which is comparable to previous works carried out with materials synthesized by conventional high-temperaturemore » solid-state routes. - Graphical abstract: Ultrafast micro-wave synthesis of Chevrel phase Cu{sub 2}Mo{sub 6}S{sub 8} towards Mo{sub 6}S{sub 8} as positive electrode of Mg-battery. - Highlights: • Chevrel phase Cu{sub 2}Mo{sub 6}S{sub 8} is synthesized by fast microwave-assisted solid-state reaction. • Highly-pure and well-crystalline Cu{sub 2}Mo{sub 6}S{sub 8} is obtained. • Mo{sub 6}S{sub 8} obtained from leaching is tested as a positive electrode for Mg batteries.« less

  10. Characterisation of chamomile volatiles by simultaneous distillation solid-phase extraction in comparison to hydrodistillation and simultaneous distillation extraction.

    PubMed

    Krüger, Hans

    2010-05-01

    A new method for complete separation of steam-volatile organic compounds is described using the example of chamomile flowers. This method is based on the direct combination of hydrodistillation and solid-phase extraction in a circulation apparatus. In contrast to hydrodistillation and simultaneous distillation extraction (SDE), an RP-18 solid phase as adsorptive material is used rather than a water-insoluble solvent. Therefore, a prompt and complete fixation of all volatiles takes place, and the circulation of water-soluble bisabololoxides as well as water-soluble and thermolabile en-yne-spiroethers is inhibited. This so-called simultaneous distillation solid-phase extraction (SD-SPE) provides extracts that better characterise the real composition of the vapour phase, as well as the composition of inhalation vapours, than do SDE extracts or essential oils obtained by hydrodistillation. The data indicate that during inhalation therapy with chamomile, the bisabololoxides and spiroethers are more strongly involved in the inhaling activity than so far assumed. Georg Thieme Verlag KG Stuttgart New York.

  11. Thermal insulating coating for spacecrafts

    NASA Technical Reports Server (NTRS)

    Kaul, Raj K. (Inventor)

    2005-01-01

    To protect spacecraft and their contents from excessive heat thermal protection systems are essential. For such thermal protection, metal coatings, ceramic materials, ablative materials, and various matrix materials have all been tried, but none have been found entirely satisfactory. The basis for this thermal protection system is the fact that the heat required to melt a substance is 80 to 100 times larger than the heat required to raise its temperature one degree. This led to the use herein of solid-liquid phase change materials. Unlike conventional heat storage materials, when phase change materials reach the temperature at which they change phase they absorb large amounts of heat without getting hotter. By this invention, then, a coating composition is provided for application to substrates subjected to temperatures above 100? F. The coating composition includes a phase change material.

  12. Thermal Insulating Coating for Spacecrafts

    NASA Technical Reports Server (NTRS)

    Kaul, Raj K. (Inventor)

    2005-01-01

    To protect spacecraft and their contents from excessive heat thermal protection system are essential. For such thermal protection, metal coatings, ceramic materials, ablative materials, and various matrix materials have all been tried, but none have been found entirely satisfactory. The basis for this thermal protection system is the fact that the heat required to melt a substance is 80 to 100 times larger than the heat required to raise its temperature one degree. This led to the use herein of solid-liquid phase change materials. Unlike conventional heat storage materials, when phase change materials reach the temperature at which they change phase they absorb large amounts of heat without getting hotter. By this invention, then, a coating composition is provided for application to substrates subjected to temperatures above 100 F. The coating composition includes a phase change material.

  13. New Density Functional Approach for Solid-Liquid-Vapor Transitions in Pure Materials

    NASA Astrophysics Data System (ADS)

    Kocher, Gabriel; Provatas, Nikolas

    2015-04-01

    A new phase field crystal (PFC) type theory is presented, which accounts for the full spectrum of solid-liquid-vapor phase transitions within the framework of a single density order parameter. Its equilibrium properties show the most quantitative features to date in PFC modeling of pure substances, and full consistency with thermodynamics in pressure-volume-temperature space is demonstrated. A method to control either the volume or the pressure of the system is also introduced. Nonequilibrium simulations show that 2- and 3-phase growth of solid, vapor, and liquid can be achieved, while our formalism also allows for a full range of pressure-induced transformations. This model opens up a new window for the study of pressure driven interactions of condensed phases with vapor, an experimentally relevant paradigm previously missing from phase field crystal theories.

  14. Solid-phase extraction sorbent consisting of alkyltrimethylammonium surfactants immobilized onto strong cation-exchange polystyrene resin.

    PubMed

    Reid, Kendra R; Kennedy, Lonnie J; Crick, Eric W; Conte, Eric D

    2002-10-25

    Presented is a solid-phase extraction sorbent material composed of cationic alkyltrimethylammonium surfactants attached to a strong cation-exchange resin via ion-exchange. The original hydrophilic cation-exchange resin is made hydrophobic by covering the surface with alkyl chains from the hydrophobic portion of the surfactant. The sorbent material now has a better ability to extract hydrophobic molecules from aqueous samples. The entire stationary phase (alkyltrimethylammonium surfactant) is removed along with the analyte during the elution step. The elution step requires a mild elution solvent consisting of 0.25 M Mg2+ in a 50% 2-propanol solution. The main advantage of using a removable stationary phase is that traditionally utilized toxic elution solvents such as methylene chloride, which are necessary to efficiently release strongly hydrophobic species from SPE stationary phases, may now be avoided. Also, the final extract is directly compatible with reversed-phase liquid chromatography. The performance of this procedure is presented using pyrene as a test molecule.

  15. Ordered structure of FeGe2 formed during solid-phase epitaxy

    NASA Astrophysics Data System (ADS)

    Jenichen, B.; Hanke, M.; Gaucher, S.; Trampert, A.; Herfort, J.; Kirmse, H.; Haas, B.; Willinger, E.; Huang, X.; Erwin, S. C.

    2018-05-01

    Fe3Si /Ge (Fe ,Si ) /Fe3Si thin-film stacks were grown by a combination of molecular beam epitaxy and solid-phase epitaxy (Ge on Fe3Si ). The stacks were analyzed using electron microscopy, electron diffraction, and synchrotron x-ray diffraction. The Ge(Fe,Si) films crystallize in the well-oriented, layered tetragonal structure FeGe2 with space group P 4 m m . This kind of structure does not exist as a bulk material and is stabilized by the solid-phase epitaxy of Ge on Fe3Si . We interpret this as an ordering phenomenon induced by minimization of the elastic energy of the epitaxial film.

  16. Method and apparatus for optimized sampling of volatilizable target substances

    DOEpatents

    Lindgren, Eric R.; Phelan, James M.

    2002-01-01

    An apparatus for capturing, from gases such as soil gas, target analytes. Target analytes may include emanations from explosive materials or from residues of explosive materials. The apparatus employs principles of sorption common to solid phase microextraction, and is best used in conjunction with analysis means such as a gas chromatograph. To sorb target analytes, the apparatus functions using various sorptive structures to capture target analyte. Depending upon the embodiment, those structures may include 1) a conventional solid-phase microextraction (SPME) fiber, 2) a SPME fiber suspended in a capillary tube (with means provided for moving gases through the capillary tube so that the gases come into close proximity to the suspended fiber), and 3) a capillary tube including an interior surface on which sorptive material (similar to that on the surface of a SPME fiber) is supported (along with means for moving gases through the capillary tube so that the gases come into close proximity to the sorptive material). In one disclosed embodiment, at least one such sorptive structure is associated with an enclosure including an opening in communication with the surface of a soil region potentially contaminated with buried explosive material such as unexploded ordnance. Emanations from explosive materials can pass into and accumulate in the enclosure where they are sorbed by the sorptive structures. Also disclosed is the use of heating means such as microwave horns to drive target analytes into the soil gas from solid and liquid phase components of the soil.

  17. Overview: Experimental studies of crystal nucleation: Metals and colloids.

    PubMed

    Herlach, Dieter M; Palberg, Thomas; Klassen, Ina; Klein, Stefan; Kobold, Raphael

    2016-12-07

    Crystallization is one of the most important phase transformations of first order. In the case of metals and alloys, the liquid phase is the parent phase of materials production. The conditions of the crystallization process control the as-solidified material in its chemical and physical properties. Nucleation initiates the crystallization of a liquid. It selects the crystallographic phase, stable or meta-stable. Its detailed knowledge is therefore mandatory for the design of materials. We present techniques of containerless processing for nucleation studies of metals and alloys. Experimental results demonstrate the power of these methods not only for crystal nucleation of stable solids but in particular also for investigations of crystal nucleation of metastable solids at extreme undercooling. This concerns the physical nature of heterogeneous versus homogeneous nucleation and nucleation of phases nucleated under non-equilibrium conditions. The results are analyzed within classical nucleation theory that defines the activation energy of homogeneous nucleation in terms of the interfacial energy and the difference of Gibbs free energies of solid and liquid. The interfacial energy acts as barrier for the nucleation process. Its experimental determination is difficult in the case of metals. In the second part of this work we therefore explore the potential of colloidal suspensions as model systems for the crystallization process. The nucleation process of colloids is observed in situ by optical observation and ultra-small angle X-ray diffraction using high intensity synchrotron radiation. It allows an unambiguous discrimination of homogeneous and heterogeneous nucleation as well as the determination of the interfacial free energy of the solid-liquid interface. Our results are used to construct Turnbull plots of colloids, which are discussed in relation to Turnbull plots of metals and support the hypothesis that colloids are useful model systems to investigate crystal nucleation.

  18. Formation of soft magnetic high entropy amorphous alloys composites containing in situ solid solution phase

    NASA Astrophysics Data System (ADS)

    Wei, Ran; Sun, Huan; Chen, Chen; Tao, Juan; Li, Fushan

    2018-03-01

    Fe-Co-Ni-Si-B high entropy amorphous alloys composites (HEAACs), which containing high entropy solid solution phase in amorphous matrix, show good soft magnetic properties and bending ductility even in optimal annealed state, were successfully developed by melt spinning method. The crystallization phase of the HEAACs is solid solution phase with body centered cubic (BCC) structure instead of brittle intermetallic phase. In addition, the BCC phase can transformed into face centered cubic (FCC) phase with temperature rise. Accordingly, Fe-Co-Ni-Si-B high entropy alloys (HEAs) with FCC structure and a small amount of BCC phase was prepared by copper mold casting method. The HEAs exhibit high yield strength (about 1200 MPa) and good plastic strain (about 18%). Meanwhile, soft magnetic characteristics of the HEAs are largely reserved from HEAACs. This work provides a new strategy to overcome the annealing induced brittleness of amorphous alloys and design new advanced materials with excellent comprehensive properties.

  19. Top-down solid-phase fabrication of nanoporous cadmium oxide architectures.

    PubMed

    Yu, Haidong; Wang, Deshen; Han, Ming-Yong

    2007-02-28

    In this article, we have demonstrated one-step solid-phase transformation from high-quality cadmium carbonate microcrystals into highly nanoporous cadmium oxide. The high crystal quality of cadmium carbonate is critical for the successful fabrication of porous nanoarchitectures with predetermined morphology and well-controlled internal structure. This novel strategy has a good potential to prepare nanoporous materials at a large scale by using perfect monolithic carbonate crystals, and it is also useful to synthesize different nanoporous materials on metal-oxide-coated substrates. Meanwhile, this simple thermal transformation of cadmium carbonate into porous structures has further been extended to convert calcium carbonate into such porous structures.

  20. Nanometer-sized materials for solid-phase extraction of trace elements.

    PubMed

    Hu, Bin; He, Man; Chen, Beibei

    2015-04-01

    This review presents a comprehensive update on the state-of-the-art of nanometer-sized materials in solid-phase extraction (SPE) of trace elements followed by atomic-spectrometry detection. Zero-dimensional nanomaterials (fullerene), one-dimensional nanomaterials (carbon nanotubes, inorganic nanotubes, and nanowires), two-dimensional nanomaterials (nanofibers), and three-dimensional nanomaterials (nanoparticles, mesoporous nanoparticles, magnetic nanoparticles, and dendrimers) for SPE are discussed, with their application for trace-element analysis and their speciation in different matrices. A variety of other novel SPE sorbents, including restricted-access sorbents, ion-imprinted polymers, and metal-organic frameworks, are also discussed, although their applications in trace-element analysis are relatively scarce so far.

  1. Computational designing and screening of solid materials for CO2capture

    NASA Astrophysics Data System (ADS)

    Duan, Yuhua

    In this presentation, we will update our progress on computational designing and screening of solid materials for CO2 capture. By combining thermodynamic database mining with first principles density functional theory and phonon lattice dynamics calculations, a theoretical screening methodology to identify the most promising CO2 sorbent candidates from the vast array of possible solid materials have been proposed and validated at NETL. The advantage of this method is that it identifies the thermodynamic properties of the CO2 capture reaction as a function of temperature and pressure without any experimental input beyond crystallographic structural information of the solid phases involved. The calculated thermodynamic properties of different classes of solid materials versus temperature and pressure changes were further used to evaluate the equilibrium properties for the CO2 adsorption/desorption cycles. According to the requirements imposed by the pre- and post- combustion technologies and based on our calculated thermodynamic properties for the CO2 capture reactions by the solids of interest, we were able to identify only those solid materials for which lower capture energy costs are expected at the desired working conditions. In addition, we present a simulation scheme to increase and decrease the turnover temperature (Tt) of solid capturing CO2 reaction by mixing other solids. Our results also show that some solid sorbents can serve as bi-functional materials: CO2 sorbent and CO oxidation catalyst. Such dual functionality could be used for removing both CO and CO2 after water-gas-shift to obtain pure H2.

  2. Apparatus and Method for Increasing the Diameter of Metal Alloy Wires Within a Molten Metal Pool

    DOEpatents

    Hartman, Alan D.; Argetsinger, Edward R.; Hansen, Jeffrey S.; Paige, Jack I.; King, Paul E.; Turner, Paul C.

    2002-01-29

    In a dip forming process the core material to be coated is introduced directly into a source block of coating material eliminating the need for a bushing entrance component. The process containment vessel or crucible is heated so that only a portion of the coating material becomes molten, leaving a solid portion of material as the entrance port of, and seal around, the core material. The crucible can contain molten and solid metals and is especially useful when coating core material with reactive metals. The source block of coating material has been machined to include a close tolerance hole of a size and shape to closely fit the core material. The core material moves first through the solid portion of the source block of coating material where the close tolerance hole has been machined, then through a solid/molten interface, and finally through the molten phase where the diameter of the core material is increased. The crucible may or may not require water-cooling depending upon the type of material used in crucible construction. The system may operate under vacuum, partial vacuum, atmospheric pressure, or positive pressure depending upon the type of source material being used.

  3. Apparatus and method for increasing the diameter of metal alloy wires within a molten metal pool

    DOEpatents

    Hartman, Alan D.; Argetsinger, Edward R.; Hansen, Jeffrey S.; Paige, Jack I.; King, Paul E.; Turner, Paul C.

    2002-01-29

    In a dip forming process the core material to be coated is introduced directly into a source block of coating material eliminating the need for a bushing entrance component. The process containment vessel or crucible is heated so that only a portion of the coating material becomes molten, leaving a solid portion of material as the entrance port of, and seal around, the core material. The crucible can contain molten and solid metals and is especially useful when coating core material with reactive metals. The source block of coating material has been machined to include a close tolerance hole of a size and shape to closely fit the core material. The core material moves first through the solid portion of the source block of coating material where the close tolerance hole has been machined, then through a solid/molten interface, and finally through the molten phase where the diameter of the core material is increased. The crucible may or may not require water-cooling depending upon the type of material used in crucible construction. The system may operate under vacuum, partial vacuum, atmospheric pressure, or positive pressure depending upon the type of source material being used.

  4. Materials research at Stanford University. [composite materials, crystal structure, acoustics

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Research activity related to the science of materials is described. The following areas are included: elastic and thermal properties of composite materials, acoustic waves and devices, amorphous materials, crystal structure, synthesis of metal-metal bonds, interactions of solids with solutions, electrochemistry, fatigue damage, superconductivity and molecular physics and phase transition kinetics.

  5. Electric-Field-Oriented Growth of Long Hair-Like Silica Microfibrils and Derived Functional Monolithic Solids

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hu, Michael Z.; DePaoli, David W.; Kuritz, Tanya

    We present a “bottom-up” fabrication approach to first grow a new class of inorganic (silica) long hair-like microfibers or microwires and then to form monolithic solid pellet that contains parallel arrays of bundled microfibers with a controlled orientation. During the sol-gel solution processing, reactive precursor species are utilized as molecular “building blocks” for the field-directed assembly growth of microfibers driven by an electric field of pulsed direct current (dc) with controlled frequency. In principle, this reactive electrofibrilation process that combines an external field with a solid-phase nucleation and growth process has no limitation on reactions (such as the one heremore » that involves sol-gel reaction chemistry) and on materials compositions (such as the example silica oxide), thus will enable bulk production of long microfibers of wide variety of inorganic materials (other oxides or metals). Furthermore, we have fabricated uniquely architectured monolithic solid materials containing aligned microfibers by “wet press” of the in-situ grown microfiber structure in the electric field. The consolidated monolithic slabs (1 cm x 1 cm x 3 mm) have shown anisotropic properties and desirable retention of DNA molecule fragments, thus, could serve as a platform stationary-phase materials for future development of capillary electrochromatography for biomolecule separations.« less

  6. Electric-Field-Oriented Growth of Long Hair-Like Silica Microfibrils and Derived Functional Monolithic Solids

    DOE PAGES

    Hu, Michael Z.; DePaoli, David W.; Kuritz, Tanya; ...

    2017-09-11

    We present a “bottom-up” fabrication approach to first grow a new class of inorganic (silica) long hair-like microfibers or microwires and then to form monolithic solid pellet that contains parallel arrays of bundled microfibers with a controlled orientation. During the sol-gel solution processing, reactive precursor species are utilized as molecular “building blocks” for the field-directed assembly growth of microfibers driven by an electric field of pulsed direct current (dc) with controlled frequency. In principle, this reactive electrofibrilation process that combines an external field with a solid-phase nucleation and growth process has no limitation on reactions (such as the one heremore » that involves sol-gel reaction chemistry) and on materials compositions (such as the example silica oxide), thus will enable bulk production of long microfibers of wide variety of inorganic materials (other oxides or metals). Furthermore, we have fabricated uniquely architectured monolithic solid materials containing aligned microfibers by “wet press” of the in-situ grown microfiber structure in the electric field. The consolidated monolithic slabs (1 cm x 1 cm x 3 mm) have shown anisotropic properties and desirable retention of DNA molecule fragments, thus, could serve as a platform stationary-phase materials for future development of capillary electrochromatography for biomolecule separations.« less

  7. The Importance of Phonons with Negative Phase Quotient in Disordered Solids.

    PubMed

    Seyf, Hamid Reza; Lv, Wei; Rohskopf, Andrew; Henry, Asegun

    2018-02-08

    Current understanding of phonons is based on the phonon gas model (PGM), which is best rationalized for crystalline materials. However, most of the phonons/modes in disordered materials have a different character and thus may contribute to heat conduction in a fundamentally different way than is described by PGM. For the modes in crystals, which have sinusoidal character, one can separate the modes into two primary categories, namely acoustic and optical modes. However, for the modes in disordered materials, such designations may no longer rigorously apply. Nonetheless, the phase quotient (PQ) is a quantity that can be used to evaluate whether a mode more so shares a distinguishing property of acoustic vibrations manifested as a positive PQ, or a distinguishing property of an optical vibrations manifested as negative PQ. In thinking about this characteristic, there is essentially no intuition regarding the role of positive vs. negative PQ vibrational modes in disordered solids. Given this gap in understanding, herein we studied the respective contributions to thermal conductivity for several disordered solids as a function of PQ. The analysis sheds light on the importance of optical like/negative PQ modes in structurally/compositionally disordered solids, whereas in crystalline materials, the contributions of optical modes are usually small.

  8. Computational study of Li2OHCl as a possible solid state battery material

    NASA Astrophysics Data System (ADS)

    Howard, Jason; Holzwarth, N. A. W.

    Preparations of Li2OHCl have recently been experimentally studied as solid state Li ion electrolytes. A disordered cubic phase is known to be stable at temperatures T >35o C. Following previous ideas, first principles supercells are constructed with up to 320 atoms to model the cubic phase. First principles molecular dynamics simulations of the cubic phase show Li ion diffusion occuring on the t =10-12 s time scale, at temperatures as low as T = 400 K. The structure of the lower temperature phase (T <35o C) is not known in detail. A reasonable model of this structure is developed by using the tetragonal ideal structure found by first principles simulations and a model Hamiltonian to account for alternative orientations of the OH groups. Supported by NSF Grant DMR-1507942. Thanks to Zachary D. Hood of GaTech and ORNL for introducing these materials to us.

  9. Kinetic precipitation of solution-phase polyoxomolybdate followed by transmission electron microscopy: a window to solution-phase nanostructure.

    PubMed

    Zhu, Yan; Cammers-Goodwin, Arthur; Zhao, Bin; Dozier, Alan; Dickey, Elizabeth C

    2004-05-17

    This study aimed to elucidate the structural nature of the polydisperse, nanoscopic components in the solution and the solid states of partially reduced polyoxomolybdate derived from the [Mo132] keplerate, [(Mo)Mo5]12-[Mo2 acetate]30. Designer tripodal hexamine-tris-crown ethers and nanoscopic molybdate coprecipitated from aqueous solution. These microcrystalline solids distributed particle radii between 2-30 nm as assayed by transmission electron microscopy (TEM). The solid materials and their particle size distributions were snap shots of the solution phase. The mother liquor of the preparation of the [Mo132] keplerate after three days revealed large species (r=20-30 nm) in the coprecipitate, whereas [Mo132] keplerate redissolved in water revealed small species (3-7 nm) in the coprecipitate. Nanoparticles of coprecipitate were more stable than solids derived solely from partially reduced molybdate. The TEM features of all material analyzed lacked facets on the nanometer length scale; however, the structures diffracted electrons and appeared to be defect-free as evidenced by Moiré patterns in the TEM images. Moiré patterns and size-invariant optical densities of the features in the micrographs suggested that the molybdate nanoparticles were vesicular.

  10. High performance of SDC and GDC core shell type composite electrolytes using methane as a fuel for low temperature SOFC

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Irshad, Muneeb; Siraj, Khurram, E-mail: razahussaini786@gmail.com, E-mail: khurram.uet@gmail.com; Javed, Fayyaz

    Nanocomposites Samarium doped Ceria (SDC), Gadolinium doped Ceria (GDC), core shell SDC amorphous Na{sub 2}CO{sub 3} (SDCC) and GDC amorphous Na{sub 2}CO{sub 3} (GDCC) were synthesized using co-precipitation method and then compared to obtain better solid oxide electrolytes materials for low temperature Solid Oxide Fuel Cell (SOFCs). The comparison is done in terms of structure, crystallanity, thermal stability, conductivity and cell performance. In present work, XRD analysis confirmed proper doping of Sm and Gd in both single phase (SDC, GDC) and dual phase core shell (SDCC, GDCC) electrolyte materials. EDX analysis validated the presence of Sm and Gd in bothmore » single and dual phase electrolyte materials; also confirming the presence of amorphous Na{sub 2}CO{sub 3} in SDCC and GDCC. From TGA analysis a steep weight loss is observed in case of SDCC and GDCC when temperature rises above 725 °C while SDC and GDC do not show any loss. The ionic conductivity and cell performance of single phase SDC and GDC nanocomposite were compared with core shell GDC/amorphous Na{sub 2}CO{sub 3} and SDC/ amorphous Na{sub 2}CO{sub 3} nanocomposites using methane fuel. It is observed that dual phase core shell electrolytes materials (SDCC, GDCC) show better performance in low temperature range than their corresponding single phase electrolyte materials (SDC, GDC) with methane fuel.« less

  11. Thermal Decomposition of the Solid Phase of Nitromethane: Ab Initio Molecular Dynamics Simulations

    NASA Astrophysics Data System (ADS)

    Chang, Jing; Lian, Peng; Wei, Dong-Qing; Chen, Xiang-Rong; Zhang, Qing-Ming; Gong, Zi-Zheng

    2010-10-01

    The Car-Parrinello molecular dynamics simulations were employed to investigate thermal decomposition of the solid nitromethane. It is found that it undergoes chemical decomposition at about 2200 K under ambient pressure. The initiation of reactions involves both proton transfer and commonly known C-N bond cleavage. About 75 species and 100 elementary reactions were observed with the final products being H2O, CO2, N2, and CNCNC. It represents the first complete simulation of solid-phase explosive reactions reported to date, which is of far-reaching implication for design and development of new energetic materials.

  12. Atomic scale dynamics of a solid state chemical reaction directly determined by annular dark-field electron microscopy.

    PubMed

    Pennycook, Timothy J; Jones, Lewys; Pettersson, Henrik; Coelho, João; Canavan, Megan; Mendoza-Sanchez, Beatriz; Nicolosi, Valeria; Nellist, Peter D

    2014-12-22

    Dynamic processes, such as solid-state chemical reactions and phase changes, are ubiquitous in materials science, and developing a capability to observe the mechanisms of such processes on the atomic scale can offer new insights across a wide range of materials systems. Aberration correction in scanning transmission electron microscopy (STEM) has enabled atomic resolution imaging at significantly reduced beam energies and electron doses. It has also made possible the quantitative determination of the composition and occupancy of atomic columns using the atomic number (Z)-contrast annular dark-field (ADF) imaging available in STEM. Here we combine these benefits to record the motions and quantitative changes in the occupancy of individual atomic columns during a solid-state chemical reaction in manganese oxides. These oxides are of great interest for energy-storage applications such as for electrode materials in pseudocapacitors. We employ rapid scanning in STEM to both drive and directly observe the atomic scale dynamics behind the transformation of Mn3O4 into MnO. The results demonstrate we now have the experimental capability to understand the complex atomic mechanisms involved in phase changes and solid state chemical reactions.

  13. Fluorescence Approaches to Growing Macromolecule Crystals

    NASA Technical Reports Server (NTRS)

    Pusey, Marc; Forsythe, Elizabeth; Achari, Aniruddha

    2006-01-01

    Trace fluorescent labeling, typically < 1%, can be a powerful aid in macromolecule crystallization. Precipitation concentrates a solute, and crystals are the most densely packed solid form. The more densely packed the fluorescing material, the more brightly the emission from it, and thus fluorescence intensity of a solid phase is a good indication of whether one has crystals or not. The more brightly fluorescing crystalline phase is easily distinguishable, even when embedded in an amorphous precipitate. This approach conveys several distinct advantages: one can see what the protein is doing in response to the imposed conditions, and distinguishing between amorphous and microcrystalline precipitated phases are considerably simpler. The higher fluorescence intensity of the crystalline phase led us to test if we could derive crystallization conditions from screen outcomes which had no obvious crystalline material, but simply "bright spots" in the precipitated phase. Preliminary results show that the presence of these bright spots, not observable under white light, is indeed a good indicator of potential crystallization conditions.

  14. Phase conjugate Twyman-Green interferometer for testing spherical surfaces and lenses and for measuring refractive indices of liquids or solid transparent materials

    NASA Technical Reports Server (NTRS)

    Shukla, R. P.; Dokhanian, Mostafa; Venkateswarlu, Putcha; George, M. C.

    1990-01-01

    The present paper describes an application of a phase conjugate Twyman-Green interferometer using barium titanate as a self-pumping mirror for testing optical components like concave and convex spherical mirrors and lenses. The aberrations introduced by the beam splitter while testing concave or convex spherical mirrors of large aperture are automatically eliminated due to self-focussing property of the phase conjugate mirror. There is no necessity for a good spherical surface as a reference surface unlike in classical Twyman-Green interferometer or Williams interferometer. The phase conjugate Twyman Green interferometer with a divergent illumination can be used as a test plate for checking spherical surfaces. A nondestructive technique for measuring the refractive indices of a Fabry Perot etalon by using a phase conjugate interferometer is also suggested. The interferometer is found to be useful for measuring the refractive indices of liquids and solid transparent materials with an accuracy of the order of + or - 0.0004.

  15. Photoluminescent Metal–Organic Frameworks for Gas Sensing

    PubMed Central

    Lin, Rui‐Biao; Liu, Si‐Yang; Ye, Jia‐Wen; Li, Xu‐Yu

    2016-01-01

    Luminescence of porous coordination polymers (PCPs) or metal–organic frameworks (MOFs) is sensitive to the type and concentration of chemical species in the surrounding environment, because these materials combine the advantages of the highly regular porous structures and various luminescence mechanisms, as well as diversified host‐guest interactions. In the past few years, luminescent MOFs have attracted more and more attention for chemical sensing of gas‐phase analytes, including common gases and vapors of solids/liquids. While liquid‐phase and gas‐phase luminescence sensing by MOFs share similar mechanisms such as host‐guest electron and/or energy transfer, exiplex formation, and guest‐perturbing of excited‐state energy level and radiation pathways, via various types of host‐guest interactions, gas‐phase sensing has its unique advantages and challenges, such as easy utilization of encapsulated guest luminophores and difficulty for accurate measurement of the intensity change. This review summarizes recent progresses by using luminescent MOFs as reusable sensing materials for detection of gases and vapors of solids/liquids especially for O2, highlighting various strategies for improving the sensitivity, selectivity, stability, and accuracy, reducing the materials cost, and developing related devices. PMID:27818903

  16. Development of thermal energy storage materials for biomedical applications.

    PubMed

    Shukla, A; Sharma, Atul; Shukla, Manjari; Chen, C R

    2015-01-01

    The phase change materials (PCMs) have been utilized widely for solar thermal energy storage (TES) devices. The quality of these materials to remain at a particular temperature during solid-liquid, liquid-solid phase transition can also be utilized for many biomedical applications as well and has been explored in recent past already. This study reports some novel PCMs developed by them, along with some existing PCMs, to be used for such biomedical applications. Interestingly, it was observed that the heating/cooling properties of these PCMs enhance the quality of a variety of biomedical applications with many advantages (non-electric, no risk of electric shock, easy to handle, easy to recharge thermally, long life, cheap and easily available, reusable) over existing applications. Results of the present study are quite interesting and exciting, opening a plethora of opportunities for more work on the subject, which require overlapping expertise of material scientists, biochemists and medical experts for broader social benefits.

  17. A review on solid phase extraction of actinides and lanthanides with amide based extractants.

    PubMed

    Ansari, Seraj A; Mohapatra, Prasanta K

    2017-05-26

    Solid phase extraction is gaining attention from separation scientists due to its high chromatographic utility. Though both grafted and impregnated forms of solid phase extraction resins are popular, the later is easy to make by impregnating a given organic extractant on to an inert solid support. Solid phase extraction on an impregnated support, also known as extraction chromatography, combines the advantages of liquid-liquid extraction and the ion exchange chromatography methods. On the flip side, the impregnated extraction chromatographic resins are less stable against leaching out of the organic extractant from the pores of the support material. Grafted resins, on the other hand, have a higher stability, which allows their prolong use. The goal of this article is a brief literature review on reported actinide and lanthanide separation methods based on solid phase extractants of both the types, i.e., (i) ligand impregnation on the solid support or (ii) ligand functionalized polymers (chemically bonded resins). Though the literature survey reveals an enormous volume of studies on the extraction chromatographic separation of actinides and lanthanides using several extractants, the focus of the present article is limited to the work carried out with amide based ligands, viz. monoamides, diamides and diglycolamides. The emphasis will be on reported applied experimental results rather than on data pertaining fundamental metal complexation. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Characterization of various two-phase materials based on thermal conductivity using modified transient plane source method

    NASA Astrophysics Data System (ADS)

    Jayachandran, S.; Prithiviraajan, R. N.; Reddy, K. S.

    2017-07-01

    This paper presents the thermal conductivity of various two-phase materials using modified transient plane source (MTPS) technique. The values are determined by using commercially available C-Therm TCi apparatus. It is specially designed for testing of low to high thermal conductivity materials in the range of 0.02 to 100 Wm-1K-1 within a temperature range of 223-473 K. The results obtained for the two-phase materials (solids, powders and liquids) are having an accuracy better than 5%. The transient method is one of the easiest and less time consuming method to determine the thermal conductivity of the materials compared to steady state methods.

  19. 40 CFR 227.32 - Liquid, suspended particulate, and solid phases of a material.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... interact with ocean water to form insoluble matter or new toxic compounds, or materials which may release toxic compounds upon deposition, the Administrator, Regional Administrator, or the District Engineer, as... the material be performed upon a mixture of the waste with ocean water rather than on the material...

  20. 40 CFR 227.32 - Liquid, suspended particulate, and solid phases of a material.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... interact with ocean water to form insoluble matter or new toxic compounds, or materials which may release toxic compounds upon deposition, the Administrator, Regional Administrator, or the District Engineer, as... the material be performed upon a mixture of the waste with ocean water rather than on the material...

  1. 40 CFR 227.32 - Liquid, suspended particulate, and solid phases of a material.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... interact with ocean water to form insoluble matter or new toxic compounds, or materials which may release toxic compounds upon deposition, the Administrator, Regional Administrator, or the District Engineer, as... the material be performed upon a mixture of the waste with ocean water rather than on the material...

  2. Process for forming a homogeneous oxide solid phase of catalytically active material

    DOEpatents

    Perry, Dale L.; Russo, Richard E.; Mao, Xianglei

    1995-01-01

    A process is disclosed for forming a homogeneous oxide solid phase reaction product of catalytically active material comprising one or more alkali metals, one or more alkaline earth metals, and one or more Group VIII transition metals. The process comprises reacting together one or more alkali metal oxides and/or salts, one or more alkaline earth metal oxides and/or salts, one or more Group VIII transition metal oxides and/or salts, capable of forming a catalytically active reaction product, in the optional presence of an additional source of oxygen, using a laser beam to ablate from a target such metal compound reactants in the form of a vapor in a deposition chamber, resulting in the deposition, on a heated substrate in the chamber, of the desired oxide phase reaction product. The resulting product may be formed in variable, but reproducible, stoichiometric ratios. The homogeneous oxide solid phase product is useful as a catalyst, and can be produced in many physical forms, including thin films, particulate forms, coatings on catalyst support structures, and coatings on structures used in reaction apparatus in which the reaction product of the invention will serve as a catalyst.

  3. Dynamics of excimer laser ablation of thin tungsten films studied by fast photography

    NASA Astrophysics Data System (ADS)

    Toth, Zsolt; Hopp, Bela; Kantor, Zoltan; Ignacz, Ferenc; Szoerenyi, Tamas; Bor, Zsolt

    1994-09-01

    The time evolution of ablation and material transport during ArF excimer laser induced blow off of tungsten films from glass substrates is studied by fast photography using delayed dye laser pulses. The analysis of experimental results combined with heat flow calculations provides evidence that tungsten removal in the solid phase is the dominant mechanism in the 40 - 200 mJ/cm2 fluence domain, while partially inhomogeneous melting is observed between 200 and 800 mJ/cm2. In this fluence range, solid fragments and a halo consisting of molten droplets are observed indicating spatial separation of the two phases. The molten phase advances faster, forming a protective mist in front of the solid piece(s). At yet higher fluences (800 - 1000 mJ/cm2), a well separated solid phase could be recorded under the halo although model calculations suggest full vaporization of the layer. This unexpected phenomenon is explained by the optical shielding effect of the halo.

  4. Method of separating lignocellulosic material into lignin, cellulose and dissolved sugars

    DOEpatents

    Black, S.K.; Hames, B.R.; Myers, M.D.

    1998-03-24

    A method is described for separating lignocellulosic material into (a) lignin, (b) cellulose, and (c) hemicellulose and dissolved sugars. Wood or herbaceous biomass is digested at elevated temperature in a single-phase mixture of alcohol, water and a water-immiscible organic solvent (e.g., a ketone). After digestion, the amount of water or organic solvent is adjusted so that there is phase separation. The lignin is present in the organic solvent, the cellulose is present in a solid pulp phase, and the aqueous phase includes hemicellulose and any dissolved sugars.

  5. Method of separating lignocellulosic material into lignin, cellulose and dissolved sugars

    DOEpatents

    Black, Stuart K.; Hames, Bonnie R.; Myers, Michele D.

    1998-01-01

    A method for separating lignocellulosic material into (a) lignin, (b) cellulose, and (c) hemicellulose and dissolved sugars. Wood or herbaceous biomass is digested at elevated temperature in a single-phase mixture of alcohol, water and a water-immiscible organic solvent (e.g., a ketone). After digestion, the amount of water or organic solvent is adjusted so that there is phase separation. The lignin is present in the organic solvent, the cellulose is present in a solid pulp phase, and the aqueous phase includes hemicellulose and any dissolved sugars.

  6. Degradation of naproxen and carbamazepine in spiked sludge by slurry and solid-phase Trametes versicolor systems.

    PubMed

    Rodríguez-Rodríguez, Carlos E; Marco-Urrea, Ernest; Caminal, Gloria

    2010-04-01

    Growth and activity of the white-rot fungus Trametes versicolor on sewage sludge were assessed in bioslurry and solid-phase systems. Bioslurry cultures with different loads of sludge (10%, 25% and 38%, w/v) were performed. A lag phase of at least 2 d appeared in the 25 and 38%-cultures, however, the total fungal biomass was higher for the latter and lower for the 10%-culture after 30 d, as revealed by ergosterol determination. Detectable laccase activity levels were found in the 10 and 25%-cultures (up to 1308 and 2588 AUL(-1), respectively) while it was negligible in the 38%-culture. Important levels of ergosterol and laccase were obtained over a 60 d period in sludge solid-phase cultures amended with different concentrations of wheat straw pellets as lignocellulosic bulking material. Degradation experiments in 25%-bioslurry cultures spiked with naproxene (NAP, analgesic) and carbamazepine (CBZ, antiepileptic) showed depletion of around 47% and 57% within 24h, respectively. Complete depletion of NAP and around 48% for CBZ were achieved within 72 h in sludge solid cultures with 38% bulking material. CBZ degradation is especially remarkable due to its high persistence in wastewater treatment plants. Results showed that T. versicolor may be an interesting bioremediation agent for elimination of emerging pollutants in sewage sludge. Copyright 2009 Elsevier Ltd. All rights reserved.

  7. Phenylboronic acid modified solid-phase extraction column: Preparation, characterization, and application to the analysis of amino acids in sepia capsule by removing the maltose.

    PubMed

    Guo, Mengzhe; Yin, Dengyang; Han, Jie; Zhang, Liyan; Li, Xiao; He, Dandan; Du, Yan; Tang, Daoquan

    2016-09-01

    Maltose, a common auxiliary material of pharmaceutical preparation, may disturb the analysis of total amino acids in sepia capsule by aldolization. Therefore, it is necessary to remove the maltose through a convenient method. In this work, a phenylboronic acid modified solid-phase extraction column has been synthesized and used to remove the maltose. The materials were synthesized by one step "thiol-ene" reaction and the parameters of the column such as absorption capacity, recovery, and absorption specificity have been investigated. The results showed the column (0.5 cm of length × 0.5 cm of inner diameter) can absorb 4.6 mg maltose with a linear absorption and absorption specificity. Then this technique was applied in the quantification of amino acids in sepia capsule. After the optimization of the method, four kinds of amino acids, which were the most abundant, were quantified by high-performance liquid chromatography with diode array detection. The amounts of the four kinds of amino acids are 1.5∼2 times more than that without the treatment of solid-phase extraction column, which almost overcomes the influence of the maltose. All the results indicate that the phenylboronic acid modified solid-phase extraction column can successfully help to accurately quantify the total amino acids in sepia capsule. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Using reweighting and free energy surface interpolation to predict solid-solid phase diagrams

    NASA Astrophysics Data System (ADS)

    Schieber, Natalie P.; Dybeck, Eric C.; Shirts, Michael R.

    2018-04-01

    Many physical properties of small organic molecules are dependent on the current crystal packing, or polymorph, of the material, including bioavailability of pharmaceuticals, optical properties of dyes, and charge transport properties of semiconductors. Predicting the most stable crystalline form at a given temperature and pressure requires determining the crystalline form with the lowest relative Gibbs free energy. Effective computational prediction of the most stable polymorph could save significant time and effort in the design of novel molecular crystalline solids or predict their behavior under new conditions. In this study, we introduce a new approach using multistate reweighting to address the problem of determining solid-solid phase diagrams and apply this approach to the phase diagram of solid benzene. For this approach, we perform sampling at a selection of temperature and pressure states in the region of interest. We use multistate reweighting methods to determine the reduced free energy differences between T and P states within a given polymorph and validate this phase diagram using several measures. The relative stability of the polymorphs at the sampled states can be successively interpolated from these points to create the phase diagram by combining these reduced free energy differences with a reference Gibbs free energy difference between polymorphs. The method also allows for straightforward estimation of uncertainties in the phase boundary. We also find that when properly implemented, multistate reweighting for phase diagram determination scales better with the size of the system than previously estimated.

  9. Numerical investigation of influence on heat transfer characteristics to pneumatically conveyed dense phase flow by selecting models and boundary conditions

    NASA Astrophysics Data System (ADS)

    Zheng, Y.; Liu, Q.; Li, Y.

    2012-03-01

    Solids moving with a gas stream in a pipeline can be found in many industrial processes, such as power generation, chemical, pharmaceutical, food and commodity transfer processes. A mass flow rate of the solids is important characteristic that is often required to be measured (and controlled) to achieve efficient utilization of energy and raw materials in pneumatic conveying systems. The methods of measuring the mass flow rate of solids in a pneumatic pipeline can be divided into direct and indirect (inferential) measurements. A thermal solids' mass flow-meter, in principle, should ideally provide a direct measurement of solids flow rate, regardless of inhomogeneities in solids' distribution and environmental impacts. One key issue in developing a thermal solids' mass flow-meter is to characterize the heat transfer between the hot pipe wall and the gas-solids dense phase flow. The Eulerian continuum modeling with gas-solid two phases is the most common method for pneumatic transport. To model a gas-solid dense phase flow passing through a heated region, the gas phase is described as a continuous phase and the particles as the second phase. This study aims to describe the heat transfer characteristics between the hot wall and the gas-solids dense phase flow in pneumatic pipelines by modeling a turbulence gas-solid plug passing through the heated region which involves several actual and crucial issues: selections of interphase exchange coefficient, near-wall region functions and different wall surface temperatures. A sensitivity analysis was discussed to identify the influence on the heat transfer characteristics by selecting different interphase exchange coefficient models and different boundary conditions. Simulation results suggest that sensitivity analysis in the choice of models is very significant. The simulation results appear to show that a combination of choosing the Syamlal-O'Brien interphase exchange coefficient model and the standard k-ɛ model along with the standard wall function model might be the best approach, by which, the simulation data seems to be closest to the experimental results.

  10. Thermodynamics of HMX Polymorphs and HMX/RDX Mixtures

    DOE PAGES

    Myint, Philip C.; Nichols, Albert L.

    2016-12-09

    In this paper, we present thermodynamic models for the five most commonly studied phases of the energetic material octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX): liquid HMX and four solid polymorphs (α-, β-, γ-, and δ-HMX). We show results for the density, heat capacity, bulk modulus, and sound speed, as well as a phase diagram that illustrates the temperature and pressure regions over which the various HMX phases are most thermodynamically stable. The models are based on the same equation of state presented in our recently published paper [Myint et al., Ind. Eng. Chem. Res., 2016, 55, 2252] on another energetic material, hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Wemore » combine our HMX and RDX models together so that the equation of state can also be applied to liquid and solid mixtures of HMX/RDX. This allows us to generate an HMX/RDX phase diagram and calculate the enthalpy change associated with a few different kinds of phase transitions that these mixtures may undergo. Our paper is the first to present a single equation of state that is capable of modeling both pure HMX and HMX/RDX mixtures. A distinct feature of HMX is the strongly metastable nature of its polymorphs. This has caused some ambiguity in the literature regarding the thermodynamic stability of α-HMX. Finally, by examining possible arrangements for the relative order of the six different solid-solid transition (α–β, α–γ, α–δ, β–γ, β–δ, and γ–δ) temperatures, we conclude that α-HMX must be thermodynamically stable so that the HMX phase diagram must have an α phase region.« less

  11. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Myint, Philip C.; Nichols, Albert L.

    In this paper, we present thermodynamic models for the five most commonly studied phases of the energetic material octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX): liquid HMX and four solid polymorphs (α-, β-, γ-, and δ-HMX). We show results for the density, heat capacity, bulk modulus, and sound speed, as well as a phase diagram that illustrates the temperature and pressure regions over which the various HMX phases are most thermodynamically stable. The models are based on the same equation of state presented in our recently published paper [Myint et al., Ind. Eng. Chem. Res., 2016, 55, 2252] on another energetic material, hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Wemore » combine our HMX and RDX models together so that the equation of state can also be applied to liquid and solid mixtures of HMX/RDX. This allows us to generate an HMX/RDX phase diagram and calculate the enthalpy change associated with a few different kinds of phase transitions that these mixtures may undergo. Our paper is the first to present a single equation of state that is capable of modeling both pure HMX and HMX/RDX mixtures. A distinct feature of HMX is the strongly metastable nature of its polymorphs. This has caused some ambiguity in the literature regarding the thermodynamic stability of α-HMX. Finally, by examining possible arrangements for the relative order of the six different solid-solid transition (α–β, α–γ, α–δ, β–γ, β–δ, and γ–δ) temperatures, we conclude that α-HMX must be thermodynamically stable so that the HMX phase diagram must have an α phase region.« less

  12. Mechanism and microstructures in Ga2O3 pseudomartensitic solid phase transition.

    PubMed

    Zhu, Sheng-Cai; Guan, Shu-Hui; Liu, Zhi-Pan

    2016-07-21

    Solid-to-solid phase transition, although widely exploited in making new materials, challenges persistently our current theory for predicting its complex kinetics and rich microstructures in transition. The Ga2O3α-β phase transformation represents such a common but complex reaction with marked change in cation coordination and crystal density, which was known to yield either amorphous or crystalline products under different synthetic conditions. Here we, via recently developed stochastic surface walking (SSW) method, resolve for the first time the atomistic mechanism of Ga2O3α-β phase transformation, the pathway of which turns out to be the first reaction pathway ever determined for a new type of diffusionless solid phase transition, namely, pseudomartensitic phase transition. We demonstrate that the sensitivity of product crystallinity is caused by its multi-step, multi-type reaction pathway, which bypasses seven intermediate phases and involves all types of elementary solid phase transition steps, i.e. the shearing of O layers (martensitic type), the local diffusion of Ga atoms (reconstructive type) and the significant lattice dilation (dilation type). While the migration of Ga atoms across the close-packed O layers is the rate-determining step and yields "amorphous-like" high energy intermediates, the shearing of O layers contributes to the formation of coherent biphase junctions and the presence of a crystallographic orientation relation, (001)α//(201[combining macron])β + [120]α//[13[combining macron]2]β. Our experiment using high-resolution transmission electron microscopy further confirms the theoretical predictions on the atomic structure of biphase junction and the formation of (201[combining macron])β twin, and also discovers the late occurrence of lattice expansion in the nascent β phase that grows out from the parent α phase. By distinguishing pseudomartensitic transition from other types of mechanisms, we propose general rules to predict the product crystallinity of solid phase transition. The new knowledge on the kinetics of pseudomartensitic transition complements the theory of diffusionless solid phase transition.

  13. Experimental data showing the thermal behavior of a flat roof with phase change material.

    PubMed

    Tokuç, Ayça; Başaran, Tahsin; Yesügey, S Cengiz

    2015-12-01

    The selection and configuration of building materials for optimal energy efficiency in a building require some assumptions and models for the thermal behavior of the utilized materials. Although the models for many materials can be considered acceptable for simulation and calculation purposes, the work for modeling the real time behavior of phase change materials is still under development. The data given in this article shows the thermal behavior of a flat roof element with a phase change material (PCM) layer. The temperature and energy given to and taken from the building element are reported. In addition the solid-liquid behavior of the PCM is tracked through images. The resulting thermal behavior of the phase change material is discussed and simulated in [1] A. Tokuç, T. Başaran, S.C. Yesügey, An experimental and numerical investigation on the use of phase change materials in building elements: the case of a flat roof in Istanbul, Build. Energy, vol. 102, 2015, pp. 91-104.

  14. Path-integral simulation of solids.

    PubMed

    Herrero, C P; Ramírez, R

    2014-06-11

    The path-integral formulation of the statistical mechanics of quantum many-body systems is described, with the purpose of introducing practical techniques for the simulation of solids. Monte Carlo and molecular dynamics methods for distinguishable quantum particles are presented, with particular attention to the isothermal-isobaric ensemble. Applications of these computational techniques to different types of solids are reviewed, including noble-gas solids (helium and heavier elements), group-IV materials (diamond and elemental semiconductors), and molecular solids (with emphasis on hydrogen and ice). Structural, vibrational, and thermodynamic properties of these materials are discussed. Applications also include point defects in solids (structure and diffusion), as well as nuclear quantum effects in solid surfaces and adsorbates. Different phenomena are discussed, as solid-to-solid and orientational phase transitions, rates of quantum processes, classical-to-quantum crossover, and various finite-temperature anharmonic effects (thermal expansion, isotopic effects, electron-phonon interactions). Nuclear quantum effects are most remarkable in the presence of light atoms, so that especial emphasis is laid on solids containing hydrogen as a constituent element or as an impurity.

  15. Stabilizing Superionic-Conducting Structures via Mixed-Anion Solid Solutions of Monocarba- closo -borate Salts

    DOE PAGES

    Tang, Wan Si; Yoshida, Koji; Soloninin, Alexei V.; ...

    2016-09-01

    Solid lithium and sodium closo-polyborate-based salts are capable of superionic conductivities surpassing even liquid electrolytes, but often only at above-ambient temperatures where their entropically driven disordered phases become stabilized. Here we show by X-ray diffraction, quasielastic neutron scattering, differential scanning calorimetry, NMR, and AC impedance measurements that by introducing 'geometric frustration' via the mixing of two different closo-polyborate anions, namely, 1-CB 9H 10- and CB 11H 12-, to form solid-solution anion-alloy salts of lithium or sodium, we can successfully suppress the formation of possible ordered phases in favor of disordered, fast-ion-conducting alloy phases over a broad temperature range from subambientmore » to high temperatures. Finally, this result exemplifies an important advancement for further improving on the remarkable conductive properties generally displayed by this class of materials and represents a practical strategy for creating tailored, ambient-temperature, solid, superionic conductors for a variety of upcoming all-solid-state energy devices of the future.« less

  16. Shock Response and Phase Transitions of MgO at Planetary Impact Conditions.

    PubMed

    Root, Seth; Shulenburger, Luke; Lemke, Raymond W; Dolan, Daniel H; Mattsson, Thomas R; Desjarlais, Michael P

    2015-11-06

    The moon-forming impact and the subsequent evolution of the proto-Earth is strongly dependent on the properties of materials at the extreme conditions generated by this violent collision. We examine the high pressure behavior of MgO, one of the dominant constituents in Earth's mantle, using high-precision, plate impact shock compression experiments performed on Sandia National Laboratories' Z Machine and extensive quantum calculations using density functional theory (DFT) and quantum Monte Carlo (QMC) methods. The combined data span from ambient conditions to 1.2 TPa and 42 000 K, showing solid-solid and solid-liquid phase boundaries. Furthermore our results indicate that under impact the solid and liquid phases coexist for more than 100 GPa, pushing complete melting to pressures in excess of 600 GPa. The high pressure required for complete shock melting has implications for a broad range of planetary collision events.

  17. All solid-state SBS phase conjugate mirror

    DOEpatents

    Dane, Clifford B.; Hackel, Lloyd A.

    1999-01-01

    A stimulated Brillouin scattering (SBS) phase conjugate laser mirror uses a solid-state nonlinear gain medium instead of the conventional liquid or high pressure gas medium. The concept has been effectively demonstrated using common optical-grade fused silica. An energy threshold of 2.5 mJ and a slope efficiency of over 90% were achieved, resulting in an overall energy reflectivity of >80% for 15 ns, 1 um laser pulses. The use of solid-state materials is enabled by a multi-pass resonant architecture which suppresses transient fluctuations that would otherwise result in damage to the SBS medium. This all solid state phase conjugator is safer, more reliable, and more easily manufactured than prior art designs. It allows nonlinear wavefront correction to be implemented in industrial and defense laser systems whose operating environments would preclude the introduction of potentially hazardous liquids or high pressure gases.

  18. All solid-state SBS phase conjugate mirror

    DOEpatents

    Dane, C.B.; Hackel, L.A.

    1999-03-09

    A stimulated Brillouin scattering (SBS) phase conjugate laser mirror uses a solid-state nonlinear gain medium instead of the conventional liquid or high pressure gas medium. The concept has been effectively demonstrated using common optical-grade fused silica. An energy threshold of 2.5 mJ and a slope efficiency of over 90% were achieved, resulting in an overall energy reflectivity of >80% for 15 ns, 1 um laser pulses. The use of solid-state materials is enabled by a multi-pass resonant architecture which suppresses transient fluctuations that would otherwise result in damage to the SBS medium. This all solid state phase conjugator is safer, more reliable, and more easily manufactured than prior art designs. It allows nonlinear wavefront correction to be implemented in industrial and defense laser systems whose operating environments would preclude the introduction of potentially hazardous liquids or high pressure gases. 8 figs.

  19. Crystal Chemistry and Electrochemistry of Li xMn 1.5Ni 0.5O 4 Solid Solution Cathode Materials

    DOE PAGES

    Kan, Wang Hay; Kuppan, Saravanan; Cheng, Lei; ...

    2017-07-19

    For ordered high-voltage spinel LiMn 1.5Ni 0.5O 4 (LMNO) with the P4 32 1 symmetry, the two consecutive two-phase transformations at ~4.7 V (vs Li +/Li), involving three cubic phases of LMNO, Li 0.5Mn 1.5Ni 0.5O 4 (L 0.5MNO), and Mn 1.5Ni 0.5O 4 (MNO), have been well-established. Such a mechanism is traditionally associated with poor kinetics due to the slow movement of the phase boundaries and the large mechanical strain resulting from the volume changes among the phases, yet ordered LMNO has been shown to have excellent rate capability. In this paper, we show the ability of the phasesmore » to dissolve into each other and determine their solubility limit. We characterized the properties of the formed solid solutions and investigated the role of non-equilibrium single-phase redox processes during the charge and discharge of LMNO. Finally, by using an array of advanced analytical techniques, such as soft and hard X-ray spectroscopy, transmission X-ray microscopy, and neutron/X-ray diffraction, as well as bond valence sum analysis, the present study examines the metastable nature of solid-solution phases and provides new insights in enabling cathode materials that are thermodynamically unstable.« less

  20. Ecological evaluation of proposed dredged material from St. Andrew Bay, Florida

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mayhew, H.L.; Word, J.Q.; Kohn, N.P.

    1993-10-01

    The US Army Corps of Engineers (USACE), Mobile District, requested that the Battelle/Marine Sciences Laboratory (MSL) conduct field sampling and chemical and biological testing to determine the suitability of potential dredged material for open ocean disposal. Sediment from St. Andrew Bay was chemically characterized and evaluated for biological toxicity and bioaccumulation of contaminants. The Tier III guidance for ocean disposal testing requires tests of water column effects (following dredged material disposal), deposited sediment toxicity, and bioaccumulation of contaminants from deposited sediment (dredged material). To meet these requirements, the MSL conducted suspended-particulate-phase (SPP) toxicity tests, solid-phase toxicity tests, and bioaccumulation testingmore » on sediment representing potential dredged material from Panama City Harbor. Physical and chemical characterization of sediment to support toxicity and bioaccumulation results was also conducted on both the test and reference sediments. The MSL collected sediment samples from five sites in St. Andrew Bay and one reference site near Lands End Peninsula. The five test sediments and the reference sediment were analyzed for physical and chemical sediment characteristics, SPP chemical contaminants, solid-phase toxicity, SPP toxicity, and bioaccumulation of contaminants.« less

  1. Characterization of rhamnolipids by liquid chromatography/mass spectrometry after solid-phase extraction.

    PubMed

    Behrens, Beate; Engelen, Jeannine; Tiso, Till; Blank, Lars Mathias; Hayen, Heiko

    2016-04-01

    Rhamnolipids are surface-active agents with a broad application potential that are produced in complex mixtures by bacteria of the genus Pseudomonas. Analysis from fermentation broth is often characterized by laborious sample preparation and requires hyphenated analytical techniques like liquid chromatography coupled to mass spectrometry (LC-MS) to obtain detailed information about sample composition. In this study, an analytical procedure based on chromatographic method development and characterization of rhamnolipid sample material by LC-MS as well as a comparison of two sample preparation methods, i.e., liquid-liquid extraction and solid-phase extraction, is presented. Efficient separation was achieved under reversed-phase conditions using a mixed propylphenyl and octadecylsilyl-modified silica gel stationary phase. LC-MS/MS analysis of a supernatant from Pseudomonas putida strain KT2440 pVLT33_rhlABC grown on glucose as sole carbon source and purified by solid-phase extraction revealed a total of 20 congeners of di-rhamnolipids, mono-rhamnolipids, and their biosynthetic precursors 3-(3-hydroxyalkanoyloxy)alkanoic acids (HAAs) with different carbon chain lengths from C8 to C14, including three rhamnolipids with uncommon C9 and C11 fatty acid residues. LC-MS and the orcinol assay were used to evaluate the developed solid-phase extraction method in comparison with the established liquid-liquid extraction. Solid-phase extraction exhibited higher yields and reproducibility as well as lower experimental effort.

  2. Fuel-Flexible Gasification-Combustion Technology for Production of H2 and Sequestration-Ready CO2

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Parag Kulkarni; Jie Guan; Raul Subia

    In the near future, the nation will continue to rely on fossil fuels for electricity, transportation, and chemicals. It is necessary to improve both the process efficiency and environmental impact of fossil fuel utilization including greenhouse gas management. GE Global Research (GEGR) investigated an innovative fuel-flexible Unmixed Fuel Processor (UFP) technology with potential to produce H{sub 2}, power, and sequestration-ready CO{sub 2} from coal and other solid fuels. The UFP technology offers the long-term potential for reduced cost, increased process efficiency relative to conventional gasification and combustion systems, and near-zero pollutant emissions. GE was awarded a contract from U.S. DOEmore » NETL to investigate and develop the UFP technology. Work started on the Phase I program in October 2000 and on the Phase II effort in April 2005. In the UFP technology, coal, water and air are simultaneously converted into (1) hydrogen rich stream that can be utilized in fuel cells or turbines, (2) CO{sub 2} rich stream for sequestration, and (3) high temperature/pressure vitiated air stream to produce electricity in a gas turbine expander. The process produces near-zero emissions with an estimated efficiency higher than Integrated Gasification Combined Cycle (IGCC) process with conventional CO{sub 2} separation. The Phase I R&D program established the chemical feasibility of the major reactions of the integrated UFP technology through lab-, bench- and pilot-scale testing. A risk analysis session was carried out at the end of Phase I effort to identify the major risks in the UFP technology and a plan was developed to mitigate these risks in the Phase II of the program. The Phase II effort focused on three high-risk areas: economics, lifetime of solids used in the UFP process, and product gas quality for turbines (or the impact of impurities in the coal on the overall system). The economic analysis included estimating the capital cost as well as the costs of hydrogen and electricity for a full-scale UFP plant. These costs were benchmarked with IGCC polygen plants with similar level of CO{sub 2} capture. Based on the promising economic analysis comparison results (performed with the help from Worley Parsons), GE recommended a 'Go' decision in April 2006 to continue the experimental investigation of the UFP technology to address the remaining risks i.e. solids lifetime and the impact of impurities in the coal on overall system. Solids attrition and lifetime risk was addressed via bench-scale experiments that monitor solids performance over time and by assessing materials interactions at operating conditions. The product gas under the third reactor (high-temperature vitiated air) operating conditions was evaluated to assess the concentration of particulates, pollutants and other impurities relative to the specifications required for gas turbine feed streams. During this investigation, agglomeration of solids used in the UFP process was identified as a serious risk that impacts the lifetime of the solids and in turn feasibility of the UFP technology. The main causes of the solids agglomeration were the combination of oxygen transfer material (OTM) reduction at temperatures {approx}1000 C and interaction between OTM and CO{sub 2} absorbing material (CAM) at high operating temperatures (>1200 C). At the end of phase II, in March 2008, GEGR recommended a 'No-go' decision for taking the UFP technology to the next level of development, i.e. development of a 3-5 MW prototype system, at this time. GEGR further recommended focused materials development research programs on improving the performance and lifetime of solids materials used in UFP or chemical looping technologies. The scale-up activities would be recommended only after mitigating the risks involved with the agglomeration and overall lifetime of the solids. This is the final report for the phase II of the DOE-funded Vision 21 program entitled 'Fuel-Flexible Gasification-Combustion Technology for Production of H{sub 2} and Sequestration-Ready CO{sub 2}' (DOE Award No. DE-FC26-00NT40974). The report focuses on the major accomplishments and lessons learned in analyzing the risks of the novel UFP technology during Phase II of the DOE program.« less

  3. Silicon Nitride Equation of State

    NASA Astrophysics Data System (ADS)

    Swaminathan, Pazhayannur; Brown, Robert

    2015-06-01

    This report presents the development a global, multi-phase equation of state (EOS) for the ceramic silicon nitride (Si3N4) . Structural forms include amorphous silicon nitride normally used as a thin film and three crystalline polymorphs. Crystalline phases include hexagonal α-Si3N4, hexagonalβ-Si3N4, and the cubic spinel c-Si3N4. Decomposition at about 1900 °C results in a liquid silicon phase and gas phase products such as molecular nitrogen, atomic nitrogen, and atomic silicon. The silicon nitride EOS was developed using EOSPro which is a new and extended version of the PANDA II code. Both codes are valuable tools and have been used successfully for a variety of material classes. Both PANDA II and EOSPro can generate a tabular EOS that can be used in conjunction with hydrocodes. The paper describes the development efforts for the component solid phases and presents results obtained using the EOSPro phase transition model to investigate the solid-solid phase transitions in relation to the available shock data. Furthermore, the EOSPro mixture model is used to develop a model for the decomposition products and then combined with the single component solid models to study the global phase diagram. Sponsored by the NASA Goddard Space Flight Center Living With a Star program office.

  4. Multi-crack imaging using nonclassical nonlinear acoustic method

    NASA Astrophysics Data System (ADS)

    Zhang, Lue; Zhang, Ying; Liu, Xiao-Zhou; Gong, Xiu-Fen

    2014-10-01

    Solid materials with cracks exhibit the nonclassical nonlinear acoustical behavior. The micro-defects in solid materials can be detected by nonlinear elastic wave spectroscopy (NEWS) method with a time-reversal (TR) mirror. While defects lie in viscoelastic solid material with different distances from one another, the nonlinear and hysteretic stress—strain relation is established with Preisach—Mayergoyz (PM) model in crack zone. Pulse inversion (PI) and TR methods are used in numerical simulation and defect locations can be determined from images obtained by the maximum value. Since false-positive defects might appear and degrade the imaging when the defects are located quite closely, the maximum value imaging with a time window is introduced to analyze how defects affect each other and how the fake one occurs. Furthermore, NEWS-TR-NEWS method is put forward to improve NEWS-TR scheme, with another forward propagation (NEWS) added to the existing phases (NEWS and TR). In the added phase, scanner locations are determined by locations of all defects imaged in previous phases, so that whether an imaged defect is real can be deduced. NEWS-TR-NEWS method is proved to be effective to distinguish real defects from the false-positive ones. Moreover, it is also helpful to detect the crack that is weaker than others during imaging procedure.

  5. Photoinduced Trans-to-cis Phase Transition of Polycrystalline Azobenzene at Low Irradiance Occurs in the Solid State

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bhattacharjee, Ujjal; Freppon, Daniel; Men, Long

    2017-07-09

    The ability to produce large-scale, reversible structural changes in a variety of materials by photoexcitation of a wide variety of azobenzene derivatives has been recognized for almost two decades. Because photoexcitation of trans-azobenzene produces the cis-isomer in solution, it has generally been inferred that the macroscopic structural changes occurring in materials are also initiated by a similar large-amplitude trans-to-cis isomerization. This paper provides the first demonstration that a trans-to-cis photoisomerization occurs in polycrystalline azobenzene, and is consistent with the previously hypothesized nature of the trigger in the photoactuated mechanisms of the materials in question. It is also demonstrated that undermore » low irradiance, trans-to-cis isomerization occurs in the solid (not via a pre-melted phase); and the presence of the cis-isomer thus lowers the melting point of the sample, providing a liquid phase. A variety of experimental techniques were employed, including X-ray diffraction measurements of polycrystalline azobenzene during exposure to laser irradiation and fluorescence measurements of the solid sample. Finally, a practical consequence of this work is that it establishes trans-azobenzene as an easily obtainable and well-defined control for monitoring photoinduced structural changes in X-ray diffraction experiments, using easily accessible laser wavelengths.« less

  6. Application of advanced oxidation processes for cleaning of industrial water generated in wet dedusting of shaft furnace gases.

    PubMed

    Czaplicka, Marianna; Kurowski, Ryszard; Jaworek, Katarzyna; Bratek, Łukasz

    2013-01-01

    The paper presents results of studies into advanced oxidation processes in 03 and 03/UV systems. An advanced oxidation process (AOP) was conducted to reduce the load of impurities in circulating waters from wet de-dusting of shaft furnace gases. Besides inorganic impurities, i.e. mainly arsenic compounds (16 g As L(-1) on average), lead, zinc, chlorides and sulphates, the waters also contain some organic material. The organic material is composed of a complex mixture that contains, amongst others, aliphatic compounds, phenol and its derivatives, pyridine bases, including pyridine, and its derivatives. The test results show degradation of organic and inorganic compounds during ozonation and photo-oxidation processes. Analysis of the solutions from the processes demonstrated that the complex organic material in the industrial water was oxidized in ozonation and in photo-oxidation, which resulted in formation of aldehydes and carboxylic acids. Kinetic degradation of selected pollutants is presented. Obtained results indicated that the O3/UV process is more effective in degradation of organic matter than ozonation. Depending on the process type, precipitation of the solid phase was observed. The efficiency of solid-phase formation was higher in photo-oxidation with ozone. It was found that the precipitated solid phase is composed mainly of arsenic, iron and oxygen.

  7. Study of the properties and the choice of alloys for bladed disks (blisks) and a method for their joining

    NASA Astrophysics Data System (ADS)

    Povarova, K. B.; Valitov, V. A.; Obsepyan, S. V.; Drozdov, A. A.; Bazyleva, O. A.; Valitova, E. V.

    2014-09-01

    The choice of materials for the bladed disks (blisks) that are intended for next-generation aviation gas turbine engines is grounded. As blade materials, single crystals of light heterophase γ' + γ VKNA-type alloys based on the γ'(Ni3Al) intermetallic compound with an ordered structure are proposed. The choice of novel deformable EP975-type nickel superalloys, which are intended for operation at 800-850°C, as the disk material is grounded. It is shown that the most effective method for forming one-piece joints of an Ni3Al-based alloy and a high-alloy EP975-type nickel superalloy is the new process of solid-phase pressure welding under conditions of high-temperature superplasticity. Solid-phase joints are formed for heterophase Ni3Al-based alloy single crystals and deformable EK61 and EP975 nickel alloys. The gradient structures in the zone of the solid-phase joints that form under the conditions of low- and high-temperature superplasticity at homologous temperatures of ˜0.6 T m and 0.9 T m are studied. The character and direction of the diffusion processes at the joint of an intermetallic alloy single crystal and a deformable polycrystalline alloy are determined.

  8. Boronate ligands in materials: determining their local environment by using a combination of IR/solid-state NMR spectroscopies and DFT calculations.

    PubMed

    Sene, Saad; Reinholdt, Marc; Renaudin, Guillaume; Berthomieu, Dorothée; Zicovich-Wilson, Claudio M; Gervais, Christel; Gaveau, Philippe; Bonhomme, Christian; Filinchuk, Yaroslav; Smith, Mark E; Nedelec, Jean-Marie; Bégu, Sylvie; Mutin, P Hubert; Laurencin, Danielle

    2013-01-14

    Boronic acids (R-B(OH)(2)) are a family of molecules that have found a large number of applications in materials science. In contrast, boronate anions (R-B(OH)(3)(-)) have hardly been used so far for the preparation of novel materials. Here, a new crystalline phase involving a boronate ligand is described, Ca[C(4)H(9)-B(OH)(3)](2), which is then used as a basis for the establishment of the spectroscopic signatures of boronates in the solid state. The phase was characterized by IR and multinuclear solid-state NMR spectroscopy ((1)H, (13)C, (11)B and (43)Ca), and then modeled by periodic DFT calculations. Anharmonic OH vibration frequencies were calculated as well as NMR parameters (by using the Gauge Including Projector Augmented Wave--GIPAW--method). These data allow relationships between the geometry around the OH groups in boronates and the IR and (1)H NMR spectroscopic data to be established, which will be key to the future interpretation of the spectra of more complex organic-inorganic materials containing boronate building blocks. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Enhanced ionic conductivity with Li 7O 2Br 3 phase in Li 3OBr anti-perovskite solid electrolyte

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhu, Jinlong; Li, Shuai; Zhang, Yi

    Cubic anti-perovskites with general formula Li 3OX (X = Cl, Br, I) were recently reported as superionic conductors with the potential for use as solid electrolytes in all-solid-state lithium ion batteries. These electrolytes are nonflammable, low-cost, and suitable for thermoplastic processing. However, the primary obstacle of its practical implementation is the relatively low ionic conductivity at room temperature. In this work, we synthesized a composite material consisting of two anti-perovskite phases, namely, cubic Li 3OBr and layered Li 7O 2Br 3, by solid state reaction routes. The results indicate that with the phase fraction of Li 7O 2Br 3 increasingmore » to 44 wt. %, the ionic conductivity increased by more than one order of magnitude compared with pure phase Li 3OBr. Formation energy calculations revealed the meta-stable nature of Li 7O 2Br 3, which supports the great difficulty in producing phase-pure Li 7O 2Br 3 at ambient pressure. Here, methods of obtaining phase-pure Li 7O 2Br 3 will continue to be explored, including both high pressure and metathesis techniques.« less

  10. Enhanced ionic conductivity with Li 7O 2Br 3 phase in Li 3OBr anti-perovskite solid electrolyte

    DOE PAGES

    Zhu, Jinlong; Li, Shuai; Zhang, Yi; ...

    2016-09-07

    Cubic anti-perovskites with general formula Li 3OX (X = Cl, Br, I) were recently reported as superionic conductors with the potential for use as solid electrolytes in all-solid-state lithium ion batteries. These electrolytes are nonflammable, low-cost, and suitable for thermoplastic processing. However, the primary obstacle of its practical implementation is the relatively low ionic conductivity at room temperature. In this work, we synthesized a composite material consisting of two anti-perovskite phases, namely, cubic Li 3OBr and layered Li 7O 2Br 3, by solid state reaction routes. The results indicate that with the phase fraction of Li 7O 2Br 3 increasingmore » to 44 wt. %, the ionic conductivity increased by more than one order of magnitude compared with pure phase Li 3OBr. Formation energy calculations revealed the meta-stable nature of Li 7O 2Br 3, which supports the great difficulty in producing phase-pure Li 7O 2Br 3 at ambient pressure. Here, methods of obtaining phase-pure Li 7O 2Br 3 will continue to be explored, including both high pressure and metathesis techniques.« less

  11. Study on the Microstructure and Liquid Phase Formation in a Semisolid Gray Cast Iron

    NASA Astrophysics Data System (ADS)

    Benati, Davi Munhoz; Ito, Kazuhiro; Kohama, Kazuyuki; Yamamoto, Hajime; Zoqui, Eugenio José

    2017-10-01

    The development of high-quality semisolid raw materials requires an understanding of the phase transformations that occur as the material is heated up to the semisolid state, i.e., its melting behavior. The microstructure of the material plays a very important role during semisolid processing as it determines the flow behavior of the material when it is formed, making a thorough understanding of the microstructural evolution essential. In this study, the phase transformations and microstructural evolution in Fe2.5C1.5Si gray cast iron specially designed for thixoforming processes as it was heated to the semisolid state were observed using in situ high-temperature confocal laser scanning microscopy. At room temperature, the alloy has a matrix of pearlite and ferrite with fine interdendritic type D flake graphite. During heating, the main transformations observed were graphite precipitation inside the grains and at the austenite grain boundaries; graphite flakes and graphite precipitates growing and becoming coarser with the increasing temperature; and the beginning of melting at around 1413 K to 1423 K (1140 °C to 1150 °C). Melting begins with the eutectic phase ( i.e., the carbon-rich phase) and continues with the primary phase (primary austenite), which is consumed as the temperature increases. Melting of the eutectic phase composed by coarsened interdendritic graphite flakes produced a semi-continuous liquid network homogeneously surrounding and wetting the dendrites of the solid phase, causing grains to detach from each other and producing the intended solid globules immersed in liquid.

  12. Ferromagnetic ordering in superatomic solids.

    PubMed

    Lee, Chul-Ho; Liu, Lian; Bejger, Christopher; Turkiewicz, Ari; Goko, Tatsuo; Arguello, Carlos J; Frandsen, Benjamin A; Cheung, Sky C; Medina, Teresa; Munsie, Timothy J S; D'Ortenzio, Robert; Luke, Graeme M; Besara, Tiglet; Lalancette, Roger A; Siegrist, Theo; Stephens, Peter W; Crowther, Andrew C; Brus, Louis E; Matsuo, Yutaka; Nakamura, Eiichi; Uemura, Yasutomo J; Kim, Philip; Nuckolls, Colin; Steigerwald, Michael L; Roy, Xavier

    2014-12-03

    In order to realize significant benefits from the assembly of solid-state materials from molecular cluster superatomic building blocks, several criteria must be met. Reproducible syntheses must reliably produce macroscopic amounts of pure material; the cluster-assembled solids must show properties that are more than simply averages of those of the constituent subunits; and rational changes to the chemical structures of the subunits must result in predictable changes in the collective properties of the solid. In this report we show that we can meet these requirements. Using a combination of magnetometry and muon spin relaxation measurements, we demonstrate that crystallographically defined superatomic solids assembled from molecular nickel telluride clusters and fullerenes undergo a ferromagnetic phase transition at low temperatures. Moreover, we show that when we modify the constituent superatoms, the cooperative magnetic properties change in predictable ways.

  13. Perspectives of advanced thermal management in solar thermochemical syngas production using a counter-flow solid-solid heat exchanger

    NASA Astrophysics Data System (ADS)

    Falter, Christoph; Sizmann, Andreas; Pitz-Paal, Robert

    2017-06-01

    A modular reactor model is presented for the description of solar thermochemical syngas production involving counter-flow heat exchangers that recuperate heat from the solid phase. The development of the model is described including heat diffusion within the reactive material as it travels through the heat exchanger, which was previously identified to be a possibly limiting factor in heat exchanger design. Heat transfer within the reactive medium is described by conduction and radiation, where the former is modeled with the three-resistor model and the latter with the Rosseland diffusion approximation. The applicability of the model is shown by the analysis of heat exchanger efficiency for different material thicknesses and porosities in a system with 8 chambers and oxidation and reduction temperatures of 1000 K and 1800 K, respectively. Heat exchanger efficiency is found to rise strongly for a reduction of material thickness, as the element mass is reduced and a larger part of the elements takes part in the heat exchange process. An increase of porosity enhances radiation heat exchange but deteriorates conduction. The overall heat exchange in the material is improved for high temperatures in the heat exchanger, as radiation dominates the energy transfer. The model is shown to be a valuable tool for the development and analysis of solar thermochemical reactor concepts involving heat exchange from the solid phase.

  14. Production of aligned microfibers and nanofibers and derived functional monoliths

    DOEpatents

    Hu, Michael Z [Knoxville, TN; DePaoli, David W [Knoxville, TN; Kuritz, Tanya [Kingston, TN; Omatete, Ogbemi [New Port Richey, FL

    2007-08-14

    The present invention comprises a method for producing microfibers and nanofibers and further fabricating derived solid monolithic materials having aligned uniform micro- or nanofibrils. A method for producing fibers ranging in diameter from micrometer-sized to nanometer-sized comprises the steps of producing an electric field and preparing a solid precipitative reaction media wherein the media comprises at least one chemical reactive precursor and a solvent having low electrical conductivity and wherein a solid precipitation reaction process for nucleation and growth of a solid phase occurs within the media. Then, subjecting the media to the electric field to induce in-situ growth of microfibers or nanofibers during the reaction process within the media causing precipitative growth of solid phase particles wherein the reaction conditions and reaction kinetics control the size, morphology and composition of the fibers. The fibers can then be wet pressed while under electric field into a solid monolith slab, dried and consolidated.

  15. Optically-controlled long-term storage and release of thermal energy in phase-change materials.

    PubMed

    Han, Grace G D; Li, Huashan; Grossman, Jeffrey C

    2017-11-13

    Thermal energy storage offers enormous potential for a wide range of energy technologies. Phase-change materials offer state-of-the-art thermal storage due to high latent heat. However, spontaneous heat loss from thermally charged phase-change materials to cooler surroundings occurs due to the absence of a significant energy barrier for the liquid-solid transition. This prevents control over the thermal storage, and developing effective methods to address this problem has remained an elusive goal. Herein, we report a combination of photo-switching dopants and organic phase-change materials as a way to introduce an activation energy barrier for phase-change materials solidification and to conserve thermal energy in the materials, allowing them to be triggered optically to release their stored latent heat. This approach enables the retention of thermal energy (about 200 J g -1 ) in the materials for at least 10 h at temperatures lower than the original crystallization point, unlocking opportunities for portable thermal energy storage systems.

  16. Persistent dopants and phase segregation in organolead mixed-halide perovskites

    DOE PAGES

    Rosales, Bryan A.; Men, Long; Cady, Sarah D.; ...

    2016-07-25

    Organolead mixed-halide perovskites such as CH 3NH 3PbX 3–aX' a (X, X' = I, Br, Cl) are interesting semiconductors because of their low cost, high photovoltaic power conversion efficiencies, enhanced moisture stability, and band gap tunability. Using a combination of optical absorption spectroscopy, powder X-ray diffraction (XRD), and, for the first time, 207Pb solid state nuclear magnetic resonance (ssNMR), we probe the extent of alloying and phase segregation in these materials. Because 207Pb ssNMR chemical shifts are highly sensitive to local coordination and electronic structure, and vary linearly with halogen electronegativity and band gap, this technique can provide the truemore » chemical speciation and composition of organolead mixed-halide perovskites. We specifically investigate samples made by three different preparative methods: solution phase synthesis, thermal annealing, and solid phase synthesis. 207Pb ssNMR reveals that nonstoichiometric dopants and semicrystalline phases are prevalent in samples made by solution phase synthesis. We show that these nanodomains are persistent after thermal annealing up to 200 °C. Further, a novel solid phase synthesis that starts from the parent, single-halide perovskites can suppress phase segregation but not the formation of dopants. Our observations are consistent with the presence of miscibility gaps and spontaneous spinodal decomposition of the mixed-halide perovskites at room temperature. This underscores how strongly different synthetic procedures impact the nanostructuring and composition of organolead halide perovskites. In conclusion, better optoelectronic properties and improved device stability and performance may be achieved through careful manipulation of the different phases and nanodomains present in these materials.« less

  17. Persistent dopants and phase segregation in organolead mixed-halide perovskites

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rosales, Bryan A.; Men, Long; Cady, Sarah D.

    Organolead mixed-halide perovskites such as CH 3NH 3PbX 3–aX' a (X, X' = I, Br, Cl) are interesting semiconductors because of their low cost, high photovoltaic power conversion efficiencies, enhanced moisture stability, and band gap tunability. Using a combination of optical absorption spectroscopy, powder X-ray diffraction (XRD), and, for the first time, 207Pb solid state nuclear magnetic resonance (ssNMR), we probe the extent of alloying and phase segregation in these materials. Because 207Pb ssNMR chemical shifts are highly sensitive to local coordination and electronic structure, and vary linearly with halogen electronegativity and band gap, this technique can provide the truemore » chemical speciation and composition of organolead mixed-halide perovskites. We specifically investigate samples made by three different preparative methods: solution phase synthesis, thermal annealing, and solid phase synthesis. 207Pb ssNMR reveals that nonstoichiometric dopants and semicrystalline phases are prevalent in samples made by solution phase synthesis. We show that these nanodomains are persistent after thermal annealing up to 200 °C. Further, a novel solid phase synthesis that starts from the parent, single-halide perovskites can suppress phase segregation but not the formation of dopants. Our observations are consistent with the presence of miscibility gaps and spontaneous spinodal decomposition of the mixed-halide perovskites at room temperature. This underscores how strongly different synthetic procedures impact the nanostructuring and composition of organolead halide perovskites. In conclusion, better optoelectronic properties and improved device stability and performance may be achieved through careful manipulation of the different phases and nanodomains present in these materials.« less

  18. Two-dimensional tin selenide nanostructures for flexible all-solid-state supercapacitors.

    PubMed

    Zhang, Chunli; Yin, Huanhuan; Han, Min; Dai, Zhihui; Pang, Huan; Zheng, Yulin; Lan, Ya-Qian; Bao, Jianchun; Zhu, Jianmin

    2014-04-22

    Due to their unique electronic and optoelectronic properties, tin selenide nanostructures show great promise for applications in energy storage and photovoltaic devices. Despite the great progress that has been achieved, the phase-controlled synthesis of two-dimensional (2D) tin selenide nanostructures remains a challenge, and their use in supercapacitors has not been explored. In this paper, 2D tin selenide nanostructures, including pure SnSe2 nanodisks (NDs), mixed-phase SnSe-SnSe2 NDs, and pure SnSe nanosheets (NSs), have been synthesized by reacting SnCl2 and trioctylphosphine (TOP)-Se with borane-tert-butylamine complex (BTBC) and 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone. Utilizing the interplay of TOP and BTBC and changing only the amount of BTBC, the phase-controlled synthesis of 2D tin selenide nanostructures is realized for the first time. Phase-dependent pseudocapacitive behavior is observed for the resulting 2D nanostructures. The specific capacitances of pure SnSe2 NDs (168 F g(-1)) and SnSe NSs (228 F g(-1)) are much higher than those of other reported materials (e.g., graphene-Mn3O4 nanorods and TiN mesoporous spheres); thus, these tin selenide materials were used to fabricate flexible, all-solid-state supercapacitors. Devices fabricated with these two tin selenide materials exhibited high areal capacitances, good cycling stabilities, excellent flexibilities, and desirable mechanical stabilities, which were comparable to or better than those reported recently for other solid-state devices based on graphene and 3D GeSe2 nanostructures. Additionally, the rate capability of the SnSe2 NDs device was much better than that of the SnSe NS device, indicating that SnSe2 NDs are promising active materials for use in high-performance, flexible, all-solid-state supercapacitors.

  19. Thermal decomposition of the solid phase of nitromethane: ab initio molecular dynamics simulations.

    PubMed

    Chang, Jing; Lian, Peng; Wei, Dong-Qing; Chen, Xiang-Rong; Zhang, Qing-Ming; Gong, Zi-Zheng

    2010-10-29

    The Car-Parrinello molecular dynamics simulations were employed to investigate thermal decomposition of the solid nitromethane. It is found that it undergoes chemical decomposition at about 2200 K under ambient pressure. The initiation of reactions involves both proton transfer and commonly known C-N bond cleavage. About 75 species and 100 elementary reactions were observed with the final products being H2O, CO2, N2, and CNCNC. It represents the first complete simulation of solid-phase explosive reactions reported to date, which is of far-reaching implication for design and development of new energetic materials.

  20. Silicon nitride equation of state

    NASA Astrophysics Data System (ADS)

    Brown, Robert C.; Swaminathan, Pazhayannur K.

    2017-01-01

    This report presents the development of a global, multi-phase equation of state (EOS) for the ceramic silicon nitride (Si3N4).1 Structural forms include amorphous silicon nitride normally used as a thin film and three crystalline polymorphs. Crystalline phases include hexagonal α-Si3N4, hexagonal β-Si3N4, and the cubic spinel c-Si3N4. Decomposition at about 1900 °C results in a liquid silicon phase and gas phase products such as molecular nitrogen, atomic nitrogen, and atomic silicon. The silicon nitride EOS was developed using EOSPro which is a new and extended version of the PANDA II code. Both codes are valuable tools and have been used successfully for a variety of material classes. Both PANDA II and EOSPro can generate a tabular EOS that can be used in conjunction with hydrocodes. The paper describes the development efforts for the component solid phases and presents results obtained using the EOSPro phase transition model to investigate the solid-solid phase transitions in relation to the available shock data that have indicated a complex and slow time dependent phase change to the c-Si3N4 phase. Furthermore, the EOSPro mixture model is used to develop a model for the decomposition products; however, the need for a kinetic approach is suggested to combine with the single component solid models to simulate and further investigate the global phase coexistences.

  1. Tailor Made Synthesis of T-Shaped and π-STACKED Dimers in the Gas Phase: Concept for Efficient Drug Design and Material Synthesis

    NASA Astrophysics Data System (ADS)

    Kumar, Sumit; Das, Aloke

    2013-06-01

    Non-covalent interactions play a key role in governing the specific functional structures of biomolecules as well as materials. Thus molecular level understanding of these intermolecular interactions can help in efficient drug design and material synthesis. It has been found from X-ray crystallography that pure hydrocarbon solids (i.e. benzene, hexaflurobenzene) have mostly slanted T-shaped (herringbone) packing arrangement whereas mixed solid hydrocarbon crystals (i.e. solid formed from mixtures of benzene and hexafluorobenzene) exhibit preferentially parallel displaced (PD) π-stacked arrangement. Gas phase spectroscopy of the dimeric complexes of the building blocks of solid pure benzene and mixed benzene-hexafluorobenzene adducts exhibit similar structural motifs observed in the corresponding crystal strcutures. In this talk, I will discuss about the jet-cooled dimeric complexes of indole with hexafluorobenzene and p-xylene in the gas phase using Resonant two photon ionzation and IR-UV double resonance spectroscopy combined with quantum chemistry calculations. In stead of studying benzene...p-xylene and benzene...hexafluorobenzene dimers, we have studied corresponding indole complexes because N-H group is much more sensitive IR probe compared to C-H group. We have observed that indole...hexafluorobenzene dimer has parallel displaced (PD) π-stacked structure whereas indole...p-xylene has slanted T-shaped structure. We have shown here selective switching of dimeric structure from T-shaped to π-stacked by changing the substituent from electron donating (-CH3) to electron withdrawing group (fluorine) in one of the complexing partners. Thus, our results demonstrate that efficient engineering of the non-covalent interactions can lead to efficient drug design and material synthesis.

  2. Promiscuous interactions and protein disaggregases determine the material state of stress-inducible RNP granules

    PubMed Central

    Kroschwald, Sonja; Maharana, Shovamayee; Mateju, Daniel; Malinovska, Liliana; Nüske, Elisabeth; Poser, Ina; Richter, Doris; Alberti, Simon

    2015-01-01

    RNA-protein (RNP) granules have been proposed to assemble by forming solid RNA/protein aggregates or through phase separation into a liquid RNA/protein phase. Which model describes RNP granules in living cells is still unclear. In this study, we analyze P bodies in budding yeast and find that they have liquid-like properties. Surprisingly, yeast stress granules adopt a different material state, which is reminiscent of solid protein aggregates and controlled by protein disaggregases. By using an assay to ectopically nucleate RNP granules, we further establish that RNP granule formation does not depend on amyloid-like aggregation but rather involves many promiscuous interactions. Finally, we show that stress granules have different properties in mammalian cells, where they show liquid-like behavior. Thus, we propose that the material state of RNP granules is flexible and that the solid state of yeast stress granules is an adaptation to extreme environments, made possible by the presence of a powerful disaggregation machine. DOI: http://dx.doi.org/10.7554/eLife.06807.001 PMID:26238190

  3. High-pressure/high-temperature polymorphs of energetic materials by first-principles simulations

    NASA Astrophysics Data System (ADS)

    Le, Nam; Schweigert, Igor

    2017-06-01

    Energetic molecular crystals exhibit complex phase diagrams that include solid-solid phase transitions, melting, and decomposition. Sorescu and Rice have recently demonstrated that first-principles molecular dynamics (MD) simulations based on dispersion-corrected density functional theory (DFT) can capture the α to γ phase transition in hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) on time scales of several picoseconds. Motivated by their work, we are using DFT-based MD to model the relative stability of solid phases in several molecular crystals. In this presentation, we report simulations of pentaerythritol tetranitrate (PETN) and 2,4,6-trinitrotoluene (TNT) under high pressures and temperatures and compare them with experimentally observed polymorphs. This work was supported by the U.S. Naval Research Laboratory via the National Research Council and by the Office of Naval Research through the U.S. Naval Research Laboratory.

  4. Investigating Li 2NiO 2–Li 2CuO 2 Solid Solutions as High-Capacity Cathode Materials for Li-Ion Batteries

    DOE PAGES

    Xu, Jing; Renfrew, Sara; Marcus, Matthew A.; ...

    2017-05-11

    Li 2Ni 1–xCu xO 2 solid solutions were prepared by a solid-state method to study the correlation between composition and electrochemical performance. Cu incorporation improved the phase purity of Li 2Ni 1–xCu xO 2 with orthorhombic Immm structure, resulting in enhanced capacity. However, the electrochemical profiles suggested Cu incorporation did not prevent irreversible phase transformation during the electrochemical process, instead, it likely influenced the phase transformation upon lithium removal. By combining ex situ X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), and differential electrochemical mass spectrometry (DEMS) measurements, this study elucidates the relevant phase transformation (e.g., crystal structure, local environment, andmore » charge compensation) and participation of electrons from lattice oxygen during the first cycle in these complex oxides.« less

  5. An agent-based method for simulating porous fluid-saturated structures with indistinguishable components

    NASA Astrophysics Data System (ADS)

    Kashani, Jamal; Pettet, Graeme John; Gu, YuanTong; Zhang, Lihai; Oloyede, Adekunle

    2017-10-01

    Single-phase porous materials contain multiple components that intermingle up to the ultramicroscopic level. Although the structures of the porous materials have been simulated with agent-based methods, the results of the available methods continue to provide patterns of distinguishable solid and fluid agents which do not represent materials with indistinguishable phases. This paper introduces a new agent (hybrid agent) and category of rules (intra-agent rule) that can be used to create emergent structures that would more accurately represent single-phase structures and materials. The novel hybrid agent carries the characteristics of system's elements and it is capable of changing within itself, while also responding to its neighbours as they also change. As an example, the hybrid agent under one-dimensional cellular automata formalism in a two-dimensional domain is used to generate patterns that demonstrate the striking morphological and characteristic similarities with the porous saturated single-phase structures where each agent of the ;structure; carries semi-permeability property and consists of both fluid and solid in space and at all times. We conclude that the ability of the hybrid agent to change locally provides an enhanced protocol to simulate complex porous structures such as biological tissues which could facilitate models for agent-based techniques and numerical methods.

  6. Expanding hollow metal rings

    DOEpatents

    Peacock, Harold B [Evans, GA; Imrich, Kenneth J [Grovetown, GA

    2009-03-17

    A sealing device that may expand more planar dimensions due to internal thermal expansion of a filler material. The sealing material is of a composition such that when desired environment temperatures and internal actuating pressures are reached, the sealing materials undergoes a permanent deformation. For metallic compounds, this permanent deformation occurs when the material enters the plastic deformation phase. Polymers, and other materials, may be using a sealing mechanism depending on the temperatures and corrosivity of the use. Internal pressures are generated by either rapid thermal expansion or material phase change and may include either liquid or solid to gas phase change, or in the gaseous state with significant pressure generation in accordance with the gas laws. Sealing material thickness and material composition may be used to selectively control geometric expansion of the seal such that expansion is limited to a specific facing and or geometric plane.

  7. Feasibility of using microencapsulated phase change materials as filler for improving low temperature performance of rubber sealing materials.

    PubMed

    Tiwari, Avinash; Shubin, Sergey N; Alcock, Ben; Freidin, Alexander B; Thorkildsen, Brede; Echtermeyer, Andreas T

    2017-11-01

    The feasibility of a novel composite rubber sealing material to improve sealing under transient cooling (in a so-called blowdown scenario) is investigated here. A composite of hydrogenated nitrile butadiene rubber (HNBR) filled with Micro Encapsulated Phase Change Materials (MEPCM) is described. The fillers contain phase change materials that release heat during the phase transformation from liquid to solid while cooling. This exotherm locally heats the rubber and may improve the function of the seal during a blowdown event. A representative HNBR-MEPCM composite was made and the critical thermal and mechanical properties were obtained by simulating the temperature distribution during a blowdown event. Simulations predict that the MEPCM composites can delay the temperature decrease in a region of the seal during the transient blowdown. A sensitivity analysis of material properties is also presented which highlights possible avenues of improvement of the MEPCMs for sealing applications.

  8. Mesoscale modeling of strain induced solid state amorphization in crystalline materials

    NASA Astrophysics Data System (ADS)

    Lei, Lei

    Solid state amorphization, and in particular crystalline to amorphous transformation, can be observed in metallic alloys, semiconductors, intermetallics, minerals, and also molecular crystals when they undergo irradiation, hydrogen gas dissolution, thermal interdiffusion, mechanical alloying, or mechanical milling. Although the amorphization mechanisms may be different, the transformation occurs due to the high level of disorder introduced into the material. Milling induced solid state amorphization is proposed to be the result of accumulation of crystal defects, specifically dislocations, as the material is subjected to large deformations during the high energy process. Thus, understanding the deformation mechanisms of crystalline materials will be the first step in studying solid state amorphization in crystalline materials, which not only has scientific contributions, but also technical consequences. A phase field dislocation dynamics (PFDD) approach is employed in this work to simulate plastic deformation of molecular crystals. This PFDD model has the advantage of tracking all of the dislocations in a material simultaneously. The model takes into account the elastic interaction between dislocations, the lattice resistance to dislocation motion, and the elastic interaction of dislocations with an external stress field. The PFDD model is employed to describe the deformation of molecular crystals with pharmaceutical applications, namely, single crystal sucrose, acetaminophen, gamma-indomethacin, and aspirin. Stress-strain curves are produced that result in expected anisotropic material response due to the activation of different slip systems and yield stresses that agree well with those from experiments. The PFDD model is coupled to a phase transformation model to study the relation between plastic deformation and the solid state amorphization of crystals that undergo milling. This model predicts the amorphous volume fraction in excellent agreement with experimental observation. Finally, we incorporate the effect of stress free surfaces to model the behavior of dislocations close to these surfaces and in the presence of voids.

  9. Visualization of electrochemically driven solid-state phase transformations using operando hard X-ray spectro-imaging

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Li, Linsen; Chen-Wiegart, Yu-chen Karen; Wang, Jiajun

    In situ techniques with high temporal, spatial and chemical resolution are key to understand ubiquitous solid-state phase transformations, which are crucial to many technological applications. Hard X-ray spectro-imaging can visualize electrochemically driven phase transformations but demands considerably large samples with strong absorption signal so far. Here we show a conceptually new data analysis method to enable operando visualization of mechanistically relevant weakly absorbing samples at the nanoscale and study electrochemical reaction dynamics of iron fluoride, a promising high-capacity conversion cathode material. In two specially designed samples with distinctive microstructure and porosity, we observe homogeneous phase transformations during both discharge andmore » charge, faster and more complete Li-storage occurring in porous polycrystalline iron fluoride, and further, incomplete charge reaction following a pathway different from conventional belief. In conclusion, these mechanistic insights provide guidelines for designing better conversion cathode materials to realize the promise of high-capacity lithium-ion batteries.« less

  10. Visualization of electrochemically driven solid-state phase transformations using operando hard X-ray spectro-imaging

    DOE PAGES

    Li, Linsen; Chen-Wiegart, Yu-chen Karen; Wang, Jiajun; ...

    2015-04-20

    In situ techniques with high temporal, spatial and chemical resolution are key to understand ubiquitous solid-state phase transformations, which are crucial to many technological applications. Hard X-ray spectro-imaging can visualize electrochemically driven phase transformations but demands considerably large samples with strong absorption signal so far. Here we show a conceptually new data analysis method to enable operando visualization of mechanistically relevant weakly absorbing samples at the nanoscale and study electrochemical reaction dynamics of iron fluoride, a promising high-capacity conversion cathode material. In two specially designed samples with distinctive microstructure and porosity, we observe homogeneous phase transformations during both discharge andmore » charge, faster and more complete Li-storage occurring in porous polycrystalline iron fluoride, and further, incomplete charge reaction following a pathway different from conventional belief. In conclusion, these mechanistic insights provide guidelines for designing better conversion cathode materials to realize the promise of high-capacity lithium-ion batteries.« less

  11. Eutectics as improved pharmaceutical materials: design, properties and characterization.

    PubMed

    Cherukuvada, Suryanarayan; Nangia, Ashwini

    2014-01-28

    Eutectics are a long known class of multi-component solids with important and useful applications in daily life. In comparison to other multi-component crystalline solids, such as salts, solid solutions, molecular complexes and cocrystals, eutectics are less studied in terms of molecular structure organization and bonding interactions. Classically, a eutectic is defined based on its low melting point compared to the individual components. In this article, we attempt to define eutectics not just based on thermal methods but from a structural organization view point, and discuss their microstructures and properties as organic materials vis-a-vis solid solutions and cocrystals. The X-ray crystal structure of a cocrystal is different from that of the individual components whereas the unit cell of a solid solution is similar to that of one of the components. Eutectics are closer to the latter species in that their crystalline arrangement is similar to the parent components but they are different with respect to the structural integrity. A solid solution possesses structural homogeneity throughout the structure (single phase) but a eutectic is a heterogeneous ensemble of individual components whose crystal structures are like discontinuous solid solutions (phase separated). Thus, a eutectic may be better defined as a conglomerate of solid solutions. A structural analysis of cocrystals, solid solutions and eutectics has led to an understanding that materials with strong adhesive (hetero) interactions between the unlike components will lead to cocrystals whereas those having stronger cohesive (homo/self) interactions will more often give rise to solid solutions (for similar structures of components) and eutectics (for different structures of components). We demonstrate that the same crystal engineering principles which have been profitably utilized for cocrystal design in the past decade can now be applied to make eutectics as novel composite materials, illustrated by stable eutectics of the hygroscopic salt of the anti-tuberculosis drug ethambutol as a case study. A current gap in the characterization of eutectic microstructure may be fulfilled through pair distribution function (PDF) analysis of X-ray diffraction data, which could be a rapid signature technique to differentiate eutectics from their components.

  12. Removal and recovery of mercury(II) from hazardous wastes using 1-(2-thiazolylazo)-2-naphthol functionalized activated carbon as solid phase extractant.

    PubMed

    Starvin, A M; Rao, T Prasada

    2004-09-10

    As a part of removal of toxic heavy metals from hazardous wastes, solid phase extraction (SPE) of mercury(II) at trace and ultra trace levels was studied using 1-(2-thiazolylazo)-2-naphthol (TAN) functionalized activated carbon (AC). The SPE material removes traces of mercury(II) quantitatively in the pH range 6.0 +/- 0.2. Other parameters that influence quantitative recovery of mercury(II), viz. percent concentration of TAN in AC, amount of TAN-AC, preconcentration time and volume of aqueous phase were varied and optimized. The possible means of removal of Hg(II) from other metal ions that are likely to be present in the wastes of the chloroalkali industry is discussed. The potential of TAN-functionalized AC SPE material for decontaminating mercury from the brine sludge and cell house effluent of a chloralkali plant has been evaluated.

  13. Structure, Chemistry and Property Correlations in FeSe and 122 Pnictides

    NASA Astrophysics Data System (ADS)

    Cava, Robert

    2010-03-01

    Determining how crystal structure and chemical bonding influence the properties of solids is at the heart of collaborative research programs between materials physicists and solid state chemists. In some materials, the high Tc copper oxides and colossal magnetoresistance manganates, for example, the subtleties of how structure, bonding and properties are coupled yields an almost baffling complexity, while in others, such as many classical intermetallic superconductors, the properties are more easily understood, with bonding and structure playing a less profound role. The new superconducting pnictides appear to fall somewhere between these two limits, and have so far been the subject of relatively little study by solid state chemists. Here I will describe some of our recent work on superconducting FeSe and superconductor-related ``122'' (ThCr2Si2-type) solid solution phases as examples of the kinds of insights that structural and chemical studies can contribute to understanding these important materials.

  14. Measurement of gas-liquid partition coefficient and headspace concentration profiles of perfume materials by solid-phase microextraction and capillary gas chromatography-mass spectrometry

    PubMed

    Liu; Wene

    2000-09-01

    An empirical model describing the relationship between the partition coefficients (K) of perfume materials in the solid-phase microextraction (SPME) fiber stationary phase and the Linearly Temperature Programmed Retention Index (LTPRI) is obtained. This is established using a mixture of eleven selected fragrance materials spiked in mineral oil at different concentration levels to simulate liquid laundry detergent matrices. Headspace concentrations of the materials are measured using both static headspace and SPME-gas chromatography analysis. The empirical model is tested by measuring the K values for fourteen perfume materials experimentally. Three of the calculated K values are within 2-19% of the measured K value, and the other eleven calculated K values are within 22-59%. This range of deviation is understandable because a diverse mixture was used to cover most chemical functionalities in order to make the model generally applicable. Better prediction accuracy is expected when a model is established using a specific category of compounds, such as hydrocarbons or aromatics. The use of this method to estimate distribution constants of fragrance materials in liquid matrices is demonstrated. The headspace SPME using the established relationship between the gas-liquid partition coefficient and the LTPRI is applied to measure the headspace concentration of fragrances. It is demonstrated that this approach can be used to monitor the headspace perfume profiles over consumer laundry and cleaning products. This method can provide high sample throughput, reproducibility, simplicity, and accuracy for many applications for screening major fragrance materials over consumer products. The approach demonstrated here can be used to translate headspace SPME results into true static headspace concentration profiles. This translation is critical for obtaining the gas-phase composition by correcting for the inherent differential partitioning of analytes into the fiber stationary phase.

  15. [Determination of patulin in fruits and jam by solid phase extraction-ultra performance liquid chromatography].

    PubMed

    Lü, Weichao; Shen, Shuchang; Wang, Chao

    2017-11-08

    With magnesium silicate, silica gel, diatomite and calcium sulfate as raw materials, a new solid phase extraction column was prepared through a series of processes of grinding to ethanol homogenate, drying and packing into polypropylene tube. The sample was hydrolyzed by pectinase, extracted by acetonitrile and purified by solid phase extraction. The target compounds were separated on a C18 column (100 mm×2.1 mm, 1.8 μm), using 0.8% (v/v) tetrahydrofuran solution as mobile phase with a flow rate of 0.5 mL/min. The detection wavelength was 276 nm. The effect of pectinase on extraction yield and purification effect of solid-phase extraction column were investigated. The optimum chromatographic conditions were selected. There was a good linear relationship between the peak heights and the mass concentrations of patulin in the range of 0.1 to 10 mg/L with the correlation coefficient ( R 2 ) of 1. The limit of detection for this method was 10.22 μg/kg. The spiked recoveries of samples were 86.58%-94.84% with the relative standard deviations (RSDs) of 1.45%-2.28%. The results indicated that the self-made solid phase extraction column had a good purification efficiency, and the UPLC had a high separation efficiency. The method is simple, accurate and of great significance for the quality and safety control of fruit products.

  16. Phase diagrams and crystal growth

    NASA Astrophysics Data System (ADS)

    Venkrbec, Jan

    1980-04-01

    Phase diagrams are briefly treated as generalized property-composition relationships, with respect to crystal technology optimization. The treatment is based on mutual interaction of three systems related to semiconductors: (a) the semiconducting material systems, (b0 the data bank, (c) the system of crystallization methods. A model is proposed enabling optimatization on the path from application requirements to the desired material. Further, several examples of the selection as to the composition of LED and laser diode material are given. Some of molten-solution-zone methods are being successfully introduced for this purpose. Common features of these methods, the application of phase diagrams, and their pecularities compared with other crystallization methods are illustrated by schematic diagrams and by examples. LPE methods, particularly the steady-state LPE methods such as Woodall's ISM and Nishizawa's TDM-CVP, and the CAM-S (Crystallization Method Providing Composition Autocontrol in Situ) have been chosen as examples. Another approach of exploiting phase diagrams for optimal material selection and for determination of growth condition before experimentation through a simple calculation is presented on InP-GaP solid solutions. Ternary phase diagrams are visualized in space through calculation and constructions based on the corresponding thermodynamic models and anaglyphs. These make it easy to observe and qualitatively analyze the crystallization of every composition. Phase diagrams can be also used as a powerful tool for the deduction of new crystallization methods. Eutectic crystallization is an example of such an approach where a modified molten-solution-zone method can give a sandwich structure with an abrupt concentration change. The concentration of a component can range from 0 to 100% in the different solid phases.

  17. Rapid determination of 54 pharmaceutical and personal care products in fish samples using microwave-assisted extraction-Hollow fiber-Liquid/solid phase microextraction.

    PubMed

    Zhang, Yi; Guo, Wen; Yue, Zhenfeng; Lin, Li; Zhao, Fengjuan; Chen, Peijin; Wu, Weidong; Zhu, Hong; Yang, Bo; Kuang, Yanyun; Wang, Jiong

    2017-04-15

    In this paper, a simple, rapid, solvent-less and environmental friendliness microextraction method, microwave-assisted extraction-hollow fiber-liquid/solid phase microextraction (MAE-HF-L/SME), was developed for simultaneous extraction and enrichment of 54 trace hydrophilic/lipophilic pharmaceutical and personal care products (PPCPs) from fish samples. A solid-phase extraction material, solid-phase microextraction (SPME) fiber, was synthesized. The SPME fiber had a homogeneous, loose structure and good mechanical properties, and they exhibited a good adsorption capacity for most PPCPs selected. The material formed the basis for the method of MAE-HF-L/SME. A method of liquid chromatography-high resolution mass spectroscopy (LC-HRMS) for analysis of 54 PPCPs. Under optimal synthesis and extraction conditions, the limits of detection (LODs, n=3) and the limits of quantitation (LOQs, n=10) for the 54 PPCPs were between 0.01-0.50μg·kg -1 and 0.052.00μg·kg -1 , respectively. Percent recoveries and the relative standard deviations (RSDs) in spiked fish samples (n=6) were between 56.3%-119.9% and 0.3%-17.1%, respectively. The microextraction process of 54 PPCPs in MAE-HF-L/SME took approximately 12min. The method has a low matrix interference and high enrichment factor and may be applicable for determination of 54 different PPCPs in fish samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Hot-water and solid-phase extraction of fluorescent whitening agents in paper materials and infant clothes followed by unequivocal determination with ion-pair chromatography-tandem mass spectrometry.

    PubMed

    Chen, Hsin-Chang; Ding, Wang-Hsien

    2006-03-10

    A comprehensive method for the determination of four stilbene-type disulfonate and one distyrylbiphenyl-type fluorescent whitening agents (FWAs) in paper materials (napkin and paper tissue) and infant clothes was developed. FWAs were extracted from paper material and cloth samples using a hot-water extraction, and the aqueous extracts were then preconcentrated with the newly developed Oasis WAX (mixed-mode of weak anion exchange and reversed-phase sorbent) solid-phase extraction cartridge. The analytes were unequivocal determined by ion pair chromatography coupled with negative electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS-MS), applying a di-n-hexyl-ammonium acetate (DHAA) as the ion-pairing reagent in mobile phase. Limits of quantitation (LOQ) were established between 0.2 and 0.9 ng/g in 2 g of samples. Recovery of five FWAs in spiked commercial samples was between 42 and 95% and RSD (n = 3) ranging from 2 to 11%. The method was finally applied to commercial samples, showing that two stilbene-type disulfonates were predominant FWAs detected in napkin and infant cloth samples.

  19. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kashkooli, Ali Ghorbani; Foreman, Evan; Farhad, Siamak

    In this study, synchrotron X-ray computed tomography has been utilized using two different imaging modes, absorption and Zernike phase contrast, to reconstruct the real three-dimensional (3D) morphology of nanostructured Li 4Ti 5O 12 (LTO) electrodes. The morphology of the high atomic number active material has been obtained using the absorption contrast mode, whereas the percolated solid network composed of active material and carbon-doped polymer binder domain (CBD) has been obtained using the Zernike phase contrast mode. The 3D absorption contrast image revealed that some LTO nano-particles tend to agglomerate and form secondary micro-sized particles with varying degrees of sphericity. Themore » tortuosity of electrode’s pore and solid phases were found to have directional dependence, different from Bruggeman’s tortuosity commonly used in macro-homogeneous models. The electrode’s heterogeneous structure was investigated by developing a numerical model to simulate galvanostatic discharge process using the Zernike phase contrast mode. The inclusion of CBD in the Zernike phase contrast results in an integrated percolated network of active material and CBD that is highly suited for continuum modeling. As a result, the simulation results highlight the importance of using the real 3D geometry since the spatial distribution of physical and electrochemical properties have a strong non-uniformity due to microstructural heterogeneities.« less

  20. A uniaxial constitutive model for superelastic NiTi SMA including R-phase and martensite transformations and thermal effects

    NASA Astrophysics Data System (ADS)

    Helbert, Guillaume; Saint-Sulpice, Luc; Arbab Chirani, Shabnam; Dieng, Lamine; Lecompte, Thibaut; Calloch, Sylvain; Pilvin, Philippe

    2017-02-01

    The well-known martensitic transformation is not always the unique solid-solid phase change in NiTi shape memory alloys (SMA). For this material, R-phase can occur from both austenite and martensite. In some applications, macroscopic strain of the material can be limited to 2%. In these cases, R-phase contribution can not be neglected anymore when compared with martensite. Furthermore, different thermomechanical couplings have to be taken into account to carefully predict strain rate effects and to better describe application conditions. In this paper, a new model taking into account various phase transformations with thermomechanical couplings is presented. This model is based on several transformation criteria. In most applications, SMA are used as wires, submitted to tensile-tensile loadings, in the superelasticity working range. Consequently, a uniaxial reduction of the model is presented for its simplicity. A thermodynamic framework is proposed. It enables to describe the internal variables evolution laws. The simple and fast identification process of model parameters is briefly presented. To verify the validity of the proposed model, simulation results are compared with experimental ones. The influences of testing temperature and strain amplitude on the material behavior is discussed. The damping capacity is also studied, using an energy-based criterion.

  1. Impact of the volume of gaseous phase in closed reactors on ANC results and modelling

    NASA Astrophysics Data System (ADS)

    Drapeau, Clémentine; Delolme, Cécile; Lassabatere, Laurent; Blanc, Denise

    2016-04-01

    The understanding of the geochemical behavior of polluted solid materials is often challenging and requires huge expenses of time and money. Nevertheless, given the increasing amounts of polluted solid materials and related risks for the environment, it is more and more crucial to understand the leaching of majors and trace metals elements from these matrices. In the designs of methods to quantify pollutant solubilization, the combination of experimental procedures with modeling approaches has recently gained attention. Among usual methods, some rely on the association of ANC and geochemical modeling. ANC experiments - Acid Neutralization Capacity - consists in adding known quantities of acid or base to a mixture of water and contaminated solid materials at a given liquid / solid ratio in closed reactors. Reactors are agitated for 48h and then pH, conductivity, redox potential, carbon, majors and heavy metal solubilized are quantified. However, in most cases, the amounts of matrix and water do not reach the total volume of reactors, leaving some space for air (gaseous phase). Despite this fact, no clear indication is given in standard procedures about the effect of this gaseous phase. Even worse, the gaseous phase is never accounted for when exploiting or modeling ANC data. The gaseous phase may exchange CO2 with the solution, which may, in turn, impact both pH and element release. This study lies within the most general framework for the use of geochemical modeling for the prediction of ANC results for the case of pure phases to real phase assemblages. In this study, we focus on the effect of the gaseous phase on ANC experiments on different mineral phases through geochemical modeling. To do so, we use PHREEQC code to model the evolution of pH and element release (including majors and heavy metals) when several matrices are put in contact with acid or base. We model the following scenarios for the gaseous phase: no gas, contact with the atmosphere (open system) and real reactors conditions (semi-closed systems). The solid phases tested are pure phases (calcite, sulfides, etc.) and synthetic assemblages mimicking complex polluted matrices. The modeling clearly shows that the systems are sensitive to the opening to the atmosphere. If the open system and the system with no gas are entirely different, "real" reactors also differ significantly from the other systems. Apparently, the presence of the gaseous phase in reactors greatly impacts pH and element release. This parameter should be accounted for in ANC experimental procedures and modeling. In addition to this numerical study, experimental results, previously obtained for urban polluted sediments, are analyzed in lights of the findings of the numerical study. This step allows us to strengthen conclusions and to pinpoint at the necessity to account for the gaseous phase when performing and modeling ANC experiments.

  2. Enthalpy-based multiple-relaxation-time lattice Boltzmann method for solid-liquid phase-change heat transfer in metal foams.

    PubMed

    Liu, Qing; He, Ya-Ling; Li, Qing

    2017-08-01

    In this paper, an enthalpy-based multiple-relaxation-time (MRT) lattice Boltzmann (LB) method is developed for solid-liquid phase-change heat transfer in metal foams under the local thermal nonequilibrium (LTNE) condition. The enthalpy-based MRT-LB method consists of three different MRT-LB models: one for flow field based on the generalized non-Darcy model, and the other two for phase-change material (PCM) and metal-foam temperature fields described by the LTNE model. The moving solid-liquid phase interface is implicitly tracked through the liquid fraction, which is simultaneously obtained when the energy equations of PCM and metal foam are solved. The present method has several distinctive features. First, as compared with previous studies, the present method avoids the iteration procedure; thus it retains the inherent merits of the standard LB method and is superior to the iteration method in terms of accuracy and computational efficiency. Second, a volumetric LB scheme instead of the bounce-back scheme is employed to realize the no-slip velocity condition in the interface and solid phase regions, which is consistent with the actual situation. Last but not least, the MRT collision model is employed, and with additional degrees of freedom, it has the ability to reduce the numerical diffusion across the phase interface induced by solid-liquid phase change. Numerical tests demonstrate that the present method can serve as an accurate and efficient numerical tool for studying metal-foam enhanced solid-liquid phase-change heat transfer in latent heat storage. Finally, comparisons and discussions are made to offer useful information for practical applications of the present method.

  3. Development and Validation of HPLC Method for Determination of Crocetin, a constituent of Saffron, in Human Serum Samples

    PubMed Central

    Mohammadpour, Amir Hooshang; Ramezani, Mohammad; Tavakoli Anaraki, Nasim; Malaekeh-Nikouei, Bizhan; Amel Farzad, Sara; Hosseinzadeh, Hossein

    2013-01-01

    Objective(s): The present study reports the development and validation of a sensitive and rapid extraction method beside high performance liquid chromatographic method for the determination of crocetin in human serum. Materials and Methods: The HPLC method was carried out by using a C18 reversed-phase column and a mobile phase composed of methanol/water/acetic acid (85:14.5:0.5 v/v/v) at the flow rate of 0.8 ml/min. The UV detector was set at 423 nm and 13-cis retinoic acid was used as the internal standard. Serum samples were pretreated with solid-phase extraction using Bond Elut C18 (200mg) cartridges or with direct precipitation using acetonitrile. Results: The calibration curves were linear over the range of 0.05-1.25 µg/ml for direct precipitation method and 0.5-5 µg/ml for solid-phase extraction. The mean recoveries of crocetin over a concentration range of 0.05-5 µg/ml serum for direct precipitation method and 0.5-5 µg/ml for solid-phase extraction were above 70 % and 60 %, respectively. The intraday coefficients of variation were 0.37- 2.6% for direct precipitation method and 0.64 - 5.43% for solid-phase extraction. The inter day coefficients of variation were 1.69 – 6.03% for direct precipitation method and 5.13-12.74% for solid-phase extraction, respectively. The lower limit of quantification for crocetin was 0.05 µg/ml for direct precipitation method and 0.5 µg/ml for solid-phase extraction. Conclusion: The validated direct precipitation method for HPLC satisfied all of the criteria that were necessary for a bioanalytical method and could reliably quantitate crocetin in human serum for future clinical pharmacokinetic study. PMID:23638292

  4. Enthalpy-based multiple-relaxation-time lattice Boltzmann method for solid-liquid phase-change heat transfer in metal foams

    NASA Astrophysics Data System (ADS)

    Liu, Qing; He, Ya-Ling; Li, Qing

    2017-08-01

    In this paper, an enthalpy-based multiple-relaxation-time (MRT) lattice Boltzmann (LB) method is developed for solid-liquid phase-change heat transfer in metal foams under the local thermal nonequilibrium (LTNE) condition. The enthalpy-based MRT-LB method consists of three different MRT-LB models: one for flow field based on the generalized non-Darcy model, and the other two for phase-change material (PCM) and metal-foam temperature fields described by the LTNE model. The moving solid-liquid phase interface is implicitly tracked through the liquid fraction, which is simultaneously obtained when the energy equations of PCM and metal foam are solved. The present method has several distinctive features. First, as compared with previous studies, the present method avoids the iteration procedure; thus it retains the inherent merits of the standard LB method and is superior to the iteration method in terms of accuracy and computational efficiency. Second, a volumetric LB scheme instead of the bounce-back scheme is employed to realize the no-slip velocity condition in the interface and solid phase regions, which is consistent with the actual situation. Last but not least, the MRT collision model is employed, and with additional degrees of freedom, it has the ability to reduce the numerical diffusion across the phase interface induced by solid-liquid phase change. Numerical tests demonstrate that the present method can serve as an accurate and efficient numerical tool for studying metal-foam enhanced solid-liquid phase-change heat transfer in latent heat storage. Finally, comparisons and discussions are made to offer useful information for practical applications of the present method.

  5. Magnetic separation of general solid particles realised by a permanent magnet

    PubMed Central

    Hisayoshi, K.; Uyeda, C.; Terada, K.

    2016-01-01

    Most existing solids are categorised as diamagnetic or weak paramagnetic materials. The possibility of magnetic motion has not been intensively considered for these materials. Here, we demonstrate for the first time that ensembles of heterogeneous particles (diamagnetic bismuth, diamond and graphite particles, as well as two paramagnetic olivines) can be dynamically separated into five fractions by the low field produced by neodymium (NdFeB) magnets during short-duration microgravity (μg). This result is in contrast to the generally accepted notion that ordinary solid materials are magnetically inert. The materials of the separated particles are identified by their magnetic susceptibility (χ), which is determined from the translating velocity. The potential of this approach as an analytical technique is comparable to that of chromatography separation because the extraction of new solid phases from a heterogeneous grain ensemble will lead to important discoveries about inorganic materials. The method is applicable for the separation of the precious samples such as lunar soils and/or the Hayabusa particles recovered from the asteroids, because even micron-order grains can be thoroughly separated without sample-loss. PMID:27929081

  6. Magnetic separation of general solid particles realised by a permanent magnet

    NASA Astrophysics Data System (ADS)

    Hisayoshi, K.; Uyeda, C.; Terada, K.

    2016-12-01

    Most existing solids are categorised as diamagnetic or weak paramagnetic materials. The possibility of magnetic motion has not been intensively considered for these materials. Here, we demonstrate for the first time that ensembles of heterogeneous particles (diamagnetic bismuth, diamond and graphite particles, as well as two paramagnetic olivines) can be dynamically separated into five fractions by the low field produced by neodymium (NdFeB) magnets during short-duration microgravity (μg). This result is in contrast to the generally accepted notion that ordinary solid materials are magnetically inert. The materials of the separated particles are identified by their magnetic susceptibility (χ), which is determined from the translating velocity. The potential of this approach as an analytical technique is comparable to that of chromatography separation because the extraction of new solid phases from a heterogeneous grain ensemble will lead to important discoveries about inorganic materials. The method is applicable for the separation of the precious samples such as lunar soils and/or the Hayabusa particles recovered from the asteroids, because even micron-order grains can be thoroughly separated without sample-loss.

  7. Magnetic separation of general solid particles realised by a permanent magnet.

    PubMed

    Hisayoshi, K; Uyeda, C; Terada, K

    2016-12-08

    Most existing solids are categorised as diamagnetic or weak paramagnetic materials. The possibility of magnetic motion has not been intensively considered for these materials. Here, we demonstrate for the first time that ensembles of heterogeneous particles (diamagnetic bismuth, diamond and graphite particles, as well as two paramagnetic olivines) can be dynamically separated into five fractions by the low field produced by neodymium (NdFeB) magnets during short-duration microgravity (μg). This result is in contrast to the generally accepted notion that ordinary solid materials are magnetically inert. The materials of the separated particles are identified by their magnetic susceptibility (χ), which is determined from the translating velocity. The potential of this approach as an analytical technique is comparable to that of chromatography separation because the extraction of new solid phases from a heterogeneous grain ensemble will lead to important discoveries about inorganic materials. The method is applicable for the separation of the precious samples such as lunar soils and/or the Hayabusa particles recovered from the asteroids, because even micron-order grains can be thoroughly separated without sample-loss.

  8. [Possibility of the species identification using blood stains located on the material evidences and bone fragments with the method of solid phase enzyme immunoassay with "IgG general-EIA-BEST" kit and human immunoglobulin G].

    PubMed

    Sidorov, V L; Shvetsova, I V; Isakova, I V

    2007-01-01

    The authors give the comparative analysis of Russian and foreign forensic medical methods of species character identification of the blood from the stains on the material evidences and bone fragments. It is shown that for this purpose it is feasible to apply human immunoglobulin G (IgG) and solid phase enzyme immunoassay (EIA) with the kit "IgG general-EIA-BEST". In comparison with the methods used in Russia this method is more sensitive, convenient for objective registration and computer processing. The results of experiments shown that it is possible to use the kit "IgG general-EIA-BEST" in forensic medicine for the species character identification of the blood from the stains on the material evidences and bone fragments.

  9. Validation of material point method for soil fluidisation analysis

    NASA Astrophysics Data System (ADS)

    Bolognin, Marco; Martinelli, Mario; Bakker, Klaas J.; Jonkman, Sebastiaan N.

    2017-06-01

    The main aim of this paper is to describe and analyse the modelling of vertical column tests that undergo fluidisation by the application of a hydraulic gradient. A recent advancement of the material point method (MPM), allows studying both stationary and non-stationary fluid flow while interacting with the solid phase. The fluidisation initiation and post-fluidisation processes of the soil will be investigated with an advanced MPM formulation (Double Point) in which the behavior of the solid and the liquid phase is evaluated separately, assigning to each of them a set of material points (MPs). The result of these simulations are compared to analytic solutions and measurements from laboratory experiments. This work is used as a benchmark test for the MPM double point formulation in the Anura3D software and to verify the feasibility of the software for possible future engineering applications.

  10. Metal-organic frameworks for analytical chemistry: from sample collection to chromatographic separation.

    PubMed

    Gu, Zhi-Yuan; Yang, Cheng-Xiong; Chang, Na; Yan, Xiu-Ping

    2012-05-15

    In modern analytical chemistry researchers pursue novel materials to meet analytical challenges such as improvements in sensitivity, selectivity, and detection limit. Metal-organic frameworks (MOFs) are an emerging class of microporous materials, and their unusual properties such as high surface area, good thermal stability, uniform structured nanoscale cavities, and the availability of in-pore functionality and outer-surface modification are attractive for diverse analytical applications. This Account summarizes our research on the analytical applications of MOFs ranging from sampling to chromatographic separation. MOFs have been either directly used or engineered to meet the demands of various analytical applications. Bulk MOFs with microsized crystals are convenient sorbents for direct application to in-field sampling and solid-phase extraction. Quartz tubes packed with MOF-5 have shown excellent stability, adsorption efficiency, and reproducibility for in-field sampling and trapping of atmospheric formaldehyde. The 2D copper(II) isonicotinate packed microcolumn has demonstrated large enhancement factors and good shape- and size-selectivity when applied to on-line solid-phase extraction of polycyclic aromatic hydrocarbons in water samples. We have explored the molecular sieving effect of MOFs for the efficient enrichment of peptides with simultaneous exclusion of proteins from biological fluids. These results show promise for the future of MOFs in peptidomics research. Moreover, nanosized MOFs and engineered thin films of MOFs are promising materials as novel coatings for solid-phase microextraction. We have developed an in situ hydrothermal growth approach to fabricate thin films of MOF-199 on etched stainless steel wire for solid-phase microextraction of volatile benzene homologues with large enhancement factors and wide linearity. Their high thermal stability and easy-to-engineer nanocrystals make MOFs attractive as new stationary phases to fabricate MOF-coated capillaries for high-resolution gas chromatography (GC). We have explored a dynamic coating approach to fabricate a MOF-coated capillary for the GC separation of important raw chemicals and persistent organic pollutants with high resolution and excellent selectivity. We have combined a MOF-coated fiber for solid-phase microextraction with a MOF-coated capillary for GC separation, which provides an effective MOF-based tandem molecular sieve platform for selective microextraction and high-resolution GC separation of target analytes in complex samples. Microsized MOFs with good solvent stability are attractive stationary phases for high-performance liquid chromatography (HPLC). These materials have shown high resolution and good selectivity and reproducibility in both the normal-phase HPLC separation of fullerenes and substituted aromatics on MIL-101 packed columns and position isomers on a MIL-53(Al) packed column and the reversed-phase HPLC separation of a wide range of analytes from nonpolar to polar and acidic to basic solutes. Despite the above achievements, further exploration of MOFs in analytical chemistry is needed. Especially, analytical application-oriented engineering of MOFs is imperative for specific applications.

  11. Thermophysical Parameters of Organic PCM Coconut Oil from T-History Method and Its Potential as Thermal Energy Storage in Indonesia

    NASA Astrophysics Data System (ADS)

    Silalahi, Alfriska O.; Sukmawati, Nissa; Sutjahja, I. M.; Kurnia, D.; Wonorahardjo, S.

    2017-07-01

    The thermophysical parameters of organic phase change material (PCM) of coconut oil (co_oil) have been studied by analyzing the temperature vs time data during liquid-solid phase transition (solidification process) based on T-history method, adopting the original version and its modified form to extract the values of mean specific heats of the solid and liquid co_oil and the heat of fusion related to phase transition of co_oil. We found that the liquid-solid phase transition occurs rather gradually, which might be due to the fact that co_oil consists of many kinds of fatty acids with the largest amount of lauric acid (about 50%), with relatively small supercooling degree. For this reason, the end of phase transition region become smeared out, although the inflection point in the temperature derivative is clearly observed signifying the drastic temperature variation between the phase transition and solid phase periods. The data have led to the values of mean specific heat of the solid and liquid co_oil that are comparable to the pure lauric acid, while the value for heat of fusion is resemble to those of the DSC result, both from references data. The advantage of co_oil as the potential sensible and latent TES for room-temperature conditioning application in Indonesia is discussed in terms of its rather broad working temperature range due to its mixture composition characteristic.

  12. Hypercrosslinked particles for the extraction of sweeteners using dispersive solid-phase extraction from environmental samples.

    PubMed

    Lakade, Sameer S; Zhou, Qing; Li, Aimin; Borrull, Francesc; Fontanals, Núria; Marcé, Rosa M

    2018-04-01

    This work presents a new extraction material, namely, Q-100, based on hypercrosslinked magnetic particles, which was tested in dispersive solid-phase extraction for a group of sweeteners from environmental samples. The hypercrosslinked Q-100 magnetic particles had the advantage of suitable pore size distribution and high surface area, and showed good retention behavior toward sweeteners. Different dispersive solid-phase extraction parameters such as amount of magnetic particles or extraction time were optimized. Under optimum conditions, Q-100 showed suitable apparent recovery, ranging in the case of river water sample from 21 to 88% for all the sweeteners, except for alitame (12%). The validated method based on dispersive solid-phase extraction using Q-100 followed by liquid chromatography with tandem mass spectrometry provided good linearity and limits of quantification between 0.01 and 0.1 μg/L. The method was applied to analyze samples from river water and effluent wastewater, and four sweeteners (acesulfame, saccharin, cyclamate, and sucralose) were found in both types of sample. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. [Simultaneous determination of 9 ultraviolet stabilizers in food plastic packaging materials by solid phase extraction-high performance liquid chromatography].

    PubMed

    Zhang, Juzhou; Li, Jing; Shao, Dongliang; Yao, Bangben; Jiang, Junshu

    2012-02-01

    An effective high performance liquid chromatographic (HPLC) method has been developed for the simultaneous determination of 9 ultraviolet stabilizers in food plastic packaging materials. The food packaging samples were firstly extracted by methanol-ethyl acetate, and then purified by a C18 solid-phase extraction (SPE) column. The target compounds were separated on a ZORBAX SB-C18 column (250 mm x 4.6 mm, 5 microm) in gradient elution mode using methanol and water as mobile phases. The detection wavelength was at 310 nm. The linear plots of the nine ultraviolet stabilizers were obtained between 0.2 and 10 mg/L, with the correlation coefficients of above 0. 999 for the nine ultraviolet stabilizers. The limits of detection for this method were in the range from 0.05 to 0.1 mg/L. The recoveries spiked in commercial food plastic packaging materials were in the range of 70.2% - 89.0% with the relative standard deviations of 0.4% - 4.5%. The results indicated that the method is simple, accurate, and suitable for the simultaneous determination of the nine ultraviolet stabilizers in food plastic packaging materials.

  14. Visualization of anisotropic-isotropic phase transformation dynamics in battery electrode particles

    DOE PAGES

    Wang, Jiajun; Karen Chen-Wiegart, Yu-chen; Eng, Christopher; ...

    2016-08-12

    Anisotropy, or alternatively, isotropy of phase transformations extensively exist in a number of solid-state materials, with performance depending on the three-dimensional transformation features. Fundamental insights into internal chemical phase evolution allow manipulating materials with desired functionalities, and can be developed via real-time multi-dimensional imaging methods. In this paper, we report a five-dimensional imaging method to track phase transformation as a function of charging time in individual lithium iron phosphate battery cathode particles during delithiation. The electrochemically driven phase transformation is initially anisotropic with a preferred boundary migration direction, but becomes isotropic as delithiation proceeds further. We also observe the expectedmore » two-phase coexistence throughout the entire charging process. Finally, we expect this five-dimensional imaging method to be broadly applicable to problems in energy, materials, environmental and life sciences.« less

  15. Flow Strength of Shocked Aluminum in the Solid-Liquid Mixed Phase Region

    NASA Astrophysics Data System (ADS)

    Reinhart, William

    2011-06-01

    Shock waves have been used to determine material properties under high shock stresses and very-high loading rates. The determination of mechanical properties such as compressive strength under shock compression has proven to be difficult and estimates of strength have been limited to approximately 100 GPa or less in aluminum. The term ``strength'' has been used in different ways. For a Von-Mises solid, the yield strength is equal to twice the shear strength of the material and represents the maximum shear stress that can be supported before yield. Many of these concepts have been applied to materials that undergo high strain-rate dynamic deformation, as in uni-axial strain shock experiments. In shock experiments, it has been observed that the shear stress in the shocked state is not equal to the shear strength, as evidenced by elastic recompressions in reshock experiments. This has led to an assumption that there is a yield surface with maximum (loading)and minimum (unloading), shear strength yet the actual shear stress lies somewhere between these values. This work provides the first simultaneous measurements of unloading velocity and flow strength for transition of solid aluminum to the liquid phase. The investigation describes the flow strength observed in 1100 (pure), 6061-T6, and 2024 aluminum in the solid-liquid mixed phase region. Reloading and unloading techniques were utilized to provide independent data on the two unknowns (τc and τo) , so that the actual critical shear strength and the shear stress at the shock state could be estimated. Three different observations indicate a change in material response for stresses of 100 to 160 GPa; 1) release wave speed (reloading where applicable) measurements, 2) yield strength measurements, and 3) estimates of Poisson's ratio, all of which provide information on the melt process including internal consistency and/or non-equilibrium and rate-dependent melt behavior. The study investigates the strength properties in the solid region and as the material transverses the solid-mixed-liquid regime. Differences observed appear to be the product of alloying and/or microstructural composition of the aluminum. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  16. The investigation of solid slag obtained by neutralization of sewage sludge.

    PubMed

    Kavaliauskas, Zydrunas; Valincius, Vitas; Stravinskas, Giedrius; Milieska, Mindaugas; Striugas, Nerijus

    2015-11-01

    The purpose of this research is to investigate the feasibility of utilizing the slag collected after gasification of organic fuel combined with sewage sludge. The residue left after gasification process is likely usable as raw material for production of supercondensers. The sewage sludge neutralization system consists of a dosing system (fuel tank), gasifier, plasma reactor, electrostatic filter, and heat exchangers. For the gasification process, dried solid sewage is supplied in proportion of 70% to biomass 30% by weight. The slag is collected in a specially designed chamber beneath the gasifier. A scanning electron microscope (SEM) was used to evaluate surface morphology of the samples. Elemental analysis of the sewage sludge slag was performed using the energy-dispersive spectroscopy (EDS) method, which showed different solid-state elements contained in the porous structure of the solid phase: carbon 29%, aluminum 26%, potassium 20%, chlorine 1%, and others. The specific surface area of the sewage sludge slag is 6.15 m(2)/g as the BET analysis shows. In order to use the slag as a secondary raw material, detailed analysis of the structure and properties is necessary for a decision on whether the slag left after gasification of sewage sludge is suitable for any further usages. Initial results indicate that the slag may be used for production of electrodes for supercapacitors. Every year thousands of tons of sewage sludge are formed in Lithuania. Sewage sludge consists of organic and inorganic compounds. Partial combustion, plasma decomposition, and other methods are used to neutralize the sewage sludge. The incineration of sewage sludge results in generation of solid-phase slag. In this paper the material structure and composition of a solid slag (formed during neutralization of sewage sludge) is considered. Also, the impact the ambient temperature on structure and composition of solid slag is analyzed.

  17. Phase formation and UV luminescence of Gd3+ doped perovskite-type YScO3

    NASA Astrophysics Data System (ADS)

    Shimizu, Yuhei; Ueda, Kazushige

    2016-10-01

    Synthesis of pure and Gd3+doped perovskite-type YScO3 was attempted by a polymerized complex (PC) method and solid state reaction (SSR) method. Crystalline phases and UV luminescence of samples were examined with varying heating temperatures. The perovskite-type single phase was not simply formed in the SSR method, as reported in some literatures, and two cubic C-type phases of starting oxide materials remained forming slightly mixed solid solutions. UV luminescence of Gd3+ doped samples increased with an increase in heating temperatures and volume of the perovskite-type phase. In contrast, a non-crystalline precursor was crystallized to a single C-type phase at 800 °C in the PC method forming a completely mixed solid solution. Then, the phase of perovskite-type YScO3 formed at 1200 °C and its single phase was obtained at 1400 °C. It was revealed that high homogeneousness of cations was essential to generate the single perovskite-phase of YScO3. Because Gd3+ ions were also dissolved into the single C-type phase in Gd3+ doped samples, intense UV luminescence was observed above 800 °C in both C-type phase and perovskite-type phase.

  18. Computational Modeling of Mixed Solids for CO2 CaptureSorbents

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Duan, Yuhua

    2015-01-01

    Since current technologies for capturing CO2 to fight global climate change are still too energy intensive, there is a critical need for development of new materials that can capture CO2 reversibly with acceptable energy costs. Accordingly, solid sorbents have been proposed to be used for CO2 capture applications through a reversible chemical transformation. By combining thermodynamic database mining with first principles density functional theory and phonon lattice dynamics calculations, a theoretical screening methodology to identify the most promising CO2 sorbent candidates from the vast array of possible solid materials has been proposed and validated. The calculated thermodynamic properties of differentmore » classes of solid materials versus temperature and pressure changes were further used to evaluate the equilibrium properties for the CO2 adsorption/desorption cycles. According to the requirements imposed by the pre- and post- combustion technologies and based on our calculated thermodynamic properties for the CO2 capture reactions by the solids of interest, we were able to screen only those solid materials for which lower capture energy costs are expected at the desired pressure and temperature conditions. Only those selected CO2 sorbent candidates were further considered for experimental validations. The ab initio thermodynamic technique has the advantage of identifying thermodynamic properties of CO2 capture reactions without any experimental input beyond crystallographic structural information of the solid phases involved. Such methodology not only can be used to search for good candidates from existing database of solid materials, but also can provide some guidelines for synthesis new materials. In this presentation, we apply our screening methodology to mixing solid systems to adjust the turnover temperature to help on developing CO2 capture Technologies.« less

  19. Stabilized antiferroelectricity in xBiScO3-(1-x)NaNbO3 lead-free ceramics with established double hysteresis loops

    NASA Astrophysics Data System (ADS)

    Gao, Lisheng; Guo, Hanzheng; Zhang, Shujun; Randall, Clive A.

    2018-02-01

    We previously reported various solid solution systems that demonstrated the stabilized antiferroelectric (P) phases in NaNbO3 through lowering the tolerance factor. However, all those reported modifications were achieved by adding A2+B4+O3 type solid solutions. A lead-free antiferroelectric (AFE) solid solution xBiScO3-(1-x)NaNbO3 was rationalized by adopting the tolerance factor design rule. Specifically, adding BiScO3 was found to effectively stabilize the AFE phase without changing the crystal symmetry of NaNbO3. Microstructure and electron zone axis diffraction patterns from transmission electron microscopy revealed the stabilized AFE (P) phase in this solid solution. Besides, the electric-field-induced polarization with a double-hysteresis loop was observed. The present results pointed out that the strategy could also be applied while adding A3+B3+O3 type solid solutions. In addition, it expanded the compositional design that can be applied to antiferroelectric materials.

  20. Variable dimensionality in the uranium fluoride/2-methyl-piperazine system: Synthesis and structures of UFO-5, -6, and -7; Zero-, one-, and two-dimensional materials with unprecedented topologies

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Francis, R.J.; Halasyamani, P.S.; Bee, J.S.

    Recently, low temperature (T < 300 C) hydrothermal reactions of inorganic precursors in the presence of organic cations have proven highly productive for the synthesis of novel solid-state materials. Interest in these materials is driven by the astonishingly diverse range of structures produced, as well as by their many potential materials chemistry applications. This report describes the high yield, phase pure hydrothermal syntheses of three new uranium fluoride phases with unprecedented structure types. Through the systematic control of the synthesis conditions the authors have successfully controlled the architecture and dimensionality of the phase formed and selectively synthesized novel zero-, one-,more » and two-dimensional materials.« less

  1. Innovative design and material solutions of thermal contact layers for high heat flux applications in fusion devices

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Federici, G.; Matera, R.; Chiocchio, S.

    1994-11-01

    One difficulty associated with the design and development of sacrificial plasma facing components that have to handle the high heat and particle fluxes in ITER is achieving the necessary contact conductance between the plasma protection material and the high-conductivity substrate in contact with the coolant. This paper presents a novel bond idea which is proposed as one of the options for the sacrificial energy dump targets located at the bottom of the divertor legs. The bonded joint in this design concept provides thermal and electrical contact between the armour and the cooled sub-structure while promoting remote, in-situ maintenance repair andmore » an easy replaceability of the armour part without disturbing the cooling pipes or rewelding neutron irradiated materials. To provide reliable and demountable adhesion, the bond consists of a metal alloy, treated in the semi-solid phase so that it leads to a fine dispersion of a globular solid phase into a liquid matrix (rheocast process). This thermal bond layer would normally operate in the solid state but could be brought reversibly to the semi-solid state during the armour replacement simply by heating it slightly above its solidus temperature. Material and design options are discussed in this paper. Possible methods of installation and removal are described, and lifetime considerations are addressed. In order to validate this concept within the ITER time-frame, a R&D programme must be rapidly implemented.« less

  2. Functional nucleic acid entrapment in sol-gel derived materials.

    PubMed

    Carrasquilla, Carmen; Brennan, John D

    2013-10-01

    Functional nucleic acids (FNAs) are single-stranded DNA or RNA molecules, typically generated through in vitro selection, that have the ability to act as receptors for target molecules (aptamers) or perform catalysis of a chemical reaction (deoxyribozymes and ribozymes). Fluorescence-signaling aptamers and deoxyribozymes have recently emerged as promising biological recognition and signaling elements, although little has been done to evaluate their potential for solid-phase assays, particularly with species made of RNA due to their lack of chemical stability and susceptibility to nuclease attack. Herein, we present a detailed overview of the methods utilized for solid-phase immobilization of FNAs using a sol-gel entrapment method that can provide protection from nuclease degradation and impart long-term chemical stability to the FNA reporter systems, while maintaining their signaling capabilities. This article will also provide a brief review of the results of such entrapment studies involving fluorescence-signaling versions of a DNA aptamer, selected RNA-cleaving deoxyribozymes, and two different RNA aptamers in a series of sol-gel derived composites, ranging from highly polar silica to hydrophobic methylsilsesquioxane-based materials. Given the ability to produce sol-gel derived materials in a variety of configurations, particularly as thin film coatings on electrodes, optical fibers, and other devices, this entrapment method should provide a useful platform for numerous solid-phase FNA-based biosensing applications. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Analysis of isothiazolinones in environmental waters by gas chromatography-mass spectrometry.

    PubMed

    Rafoth, Astrid; Gabriel, Sabine; Sacher, Frank; Brauch, Heinz-Jürgen

    2007-09-14

    This paper describes an analytical method for the determination of five biocides of isothiazolinone type (2-methyl-3-isothiazolinone (MI), 5-chloro-2-methyl-3-isothiazolinone (CMI), 1,2-benzisothiazolinone (BIT), 2-octyl-3-isothiazolinone (OI), 4,5-dichloro-2-octyl-3-isothiazolinone (DCOI)) in environmental waters. The method is based on pre-concentration of the analytes by solid-phase extraction onto a mixture of a polymeric material and RP-C18 material and subsequent determination by gas chromatography-mass spectrometry (GC-MS). One of the target compounds (BIT) is derivatised with diazomethane after pre-concentration to improve its chromatographic performance. The method was optimised with respect to pre-concentration conditions (liquid-liquid extraction versus solid-phase extraction, solid-phase material, elution solvent and volume) and extensively validated. Applying the method to surface waters, groundwaters, and drinking waters, limits of detection between 0.01 and 0.1 microg/l could be achieved and the repeatability was below 10% for all compounds except for MI. Additional investigations showed that the stability of the isothiazolinones in environmental waters is limited and sample storage at 4 degrees C is mandatory to preserve the target biocides. First investigations of influents and effluents of a wastewater treatment plant showed that conventional wastewater treatment exhibits a high efficiency for removal of the isothiazolinones. In river waters, the target isothiazolinones could not be detected.

  4. Room temperature synthesis of copper indium diselenide in non-aqueous solution using an organoindium reagent

    NASA Technical Reports Server (NTRS)

    Hepp, Aloysius F.; Andras, Maria T.; Bailey, Sheila G.; Duraj, Stan A.

    1992-01-01

    A novel two-phase synthesis of CuInSe2 at 25 C from Cu2Se and Cp3In in 4-methylpyridine has been discovered. Characterization of the material produced shows it to be platelet-shaped crystallites with an average particle size of 10 microns, less than 2 percent C and H, with a small amount of unidentified crystalline impurity. The results demonstrate that it is possible to produce from solution a material that is ordinarily synthesized in bulk or films at much higher temperatures or using extraneous reagents and/or electrons. The use of a solid-state reagent as a starting material which is converted to another solid-state compound by an organometallic reagent has tremendous potential to produce precursors for a wide range of solid-state materials of interest to the electronics, defense, and aerospace communities.

  5. Thermodynamic Analysis of the Combustion of Metallic Materials

    NASA Technical Reports Server (NTRS)

    Wilson, D. Bruce; Stoltzfus, Joel M.

    2000-01-01

    Two types of computer codes are available to assist in the thermodynamic analysis of metallic materials combustion. One type of code calculates phase equilibrium data and is represented by CALPHAD. The other type of code calculates chemical reaction by the Gordon-McBride code. The first has seen significant application for alloy-phase diagrams, but only recently has it been considered for oxidation systems. The Gordon-McBride code has been applied to the combustion of metallic materials. Both codes are limited by their treatment of non-ideal solutions and the fact they are limited to treating volatile and gaseous species as ideal. This paper examines the significance of these limitations for combustion of metallic materials. In addition, the applicability of linear-free energy relationships for solid-phase oxidation and their possible extension to liquid-phase systems is examined.

  6. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Du Hongliang; Zhou Wancheng; Luo Fa

    The (1-x)(K{sub 0.5}Na{sub 0.5})NbO{sub 3}-x(Ba{sub 0.5}Sr{sub 0.5})TiO{sub 3} (KNN-BST) solid solution has been synthesized by conventional solid-state sintering in order to search for the new lead-free relaxor ferroelectrics for high temperature applications. The phase structure, dielectric properties, and relaxor behavior of the (1-x)KNN-xBST solid solution are systematically investigated. The phase structure of the (1-x)KNN-xBST solid solution gradually changes from pure perovskite phase with an orthorhombic symmetry to the tetragonal symmetry, then to the pseudocubic phase, and to the cubic phase with increasing addition of BST. The 0.90KNN-0.10BST solid solution shows a broad dielectric peak with permittivity maximum near 2500 andmore » low dielectric loss (<4%) in the temperature range of 100-250 deg. C. The result indicates that this material may have great potential for a variety of high temperature applications. The diffuse phase transition and the temperature of the maximum dielectric permittivity shifting toward higher temperature with increasing frequency, which are two typical characteristics for relaxor ferroelectrics, are observed in the (1-x)KNN-xBST solid solution. The dielectric relaxor behavior obeys a modified Curie-Weiss law and a Vogel-Fulcher relationship. The relaxor nature is attributed to the appearance of polar nanoregions owing to the formation of randon fields including local electric fields and elastic fields. These results confirm that the KNN-based relaxor ferroelectrics can be regarded as an alternative direction for the development of high temperature lead-free relaxor ferroelectrics.« less

  7. Oriented antibody immobilization to polystyrene macrocarriers for immunoassay modified with hydrazide derivatives of poly(meth)acrylic acid

    PubMed Central

    Shmanai, Vadim V; Nikolayeva, Tamara A; Vinokurova, Ludmila G; Litoshka, Anatoli A

    2001-01-01

    Background Hydrophobic polystyrene is the most common material for solid phase immunoassay. Proteins are immobilized on polystyrene by passive adsorption, which often causes considerable denaturation. Biological macromolecules were found to better retain their functional activity when immobilized on hydrophilic materials. Polyacrylamide is a common material for solid-phase carriers of biological macromolecules, including immunoreagents used in affinity chromatography. New macroformats for immunoassay modified with activated polyacrylamide derivatives seem to be promising. Results New polymeric matrices for immunoassay in the form of 0.63-cm balls which contain hydrazide functional groups on hydrophilic polymer spacer arms at their surface shell are synthesized by modification of aldehyde-containing polystyrene balls with hydrazide derivatives of poly(meth)acrylic acid. The beads contain up to 0.31 μmol/cm2 active hydrazide groups accessible for covalent reaction with periodate-oxidized antibodies. The matrices obtained allow carrying out the oriented antibody immobilization, which increases the functional activity of immunosorbents. Conclusions An efficient site-directed antibody immobilization on a macrosupport is realized. The polymer hydrophilic spacer arms are the most convenient and effective tools for oriented antibody coupling with molded materials. The suggested scheme can be used for the modification of any other solid supports containing electrophilic groups reacting with hydrazides. PMID:11545680

  8. Heating of solid earthen material, measuring moisture and resistivity

    DOEpatents

    Heath, W.O.; Richardson, R.L.; Goheen, S.C.

    1994-07-19

    The present invention includes a method of treating solid earthen material having volatile, semi-volatile, and non-volatile contaminants. Six electrodes are inserted into a region of earthen material to be treated in a substantially equilateral hexagonal arrangement. Six phases of voltages are applied to corresponding electrodes. The voltages are adjusted within a first range of voltages to create multiple current paths between pairs of the electrodes. The current paths are evenly distributed throughout the region defined by the electrodes and therefore uniformly heat the region. The region of earthen material is heated to a temperature sufficient to substantially remove volatile and semi-volatile contaminants by promoting microbial action. This temperature is less than a melting temperature of the earthen material. 13 figs.

  9. Heating of solid earthen material, measuring moisture and resistivity

    DOEpatents

    Heath, William O.; Richardson, Richard L.; Goheen, Steven C.

    1994-01-01

    The present invention includes a method of treating solid earthen material having volatile, semi-volatile, and non-volatile contaminants. Six electrodes are inserted into a region of earthen material to be treated in a substantially equilateral hexagonal arrangement. Six phases of voltages are applied to corresponding electrodes. The voltages are adjusted within a first range of voltages to create multiple current paths between pairs of the electrodes. The current paths are evenly distributed throughout the region defined by the electrodes and therefore uniformly heat the region. The region of earthen material is heated to a temperature sufficient to substantially remove volatile and semi-volatile contaminants by promoting microbial action. This temperature is less than a melting temperature of the earthen material.

  10. Nanolayered Features of Collagen-like Peptides

    NASA Technical Reports Server (NTRS)

    Valluzzi, Regina; Bini, Elisabetta; Haas, Terry; Cebe, Peggy; Kaplan, David L.

    2003-01-01

    We have been investigating collagen-like model oligopeptides as molecular bases for complex ordered biomimetic materials. The collagen-like molecules incorporate aspects of native collagen sequence and secondary structure. Designed modifications to native primary and secondary structure have been incorporated to control the nanostructure and microstructure of the collagen-like materials produced. We find that the collagen-like molecules form a number of lyotropic rod liquid crystalline phases, which because of their strong temperature dependence in the liquid state can also be viewed as solvent intercalated thermotropic liquid crystals. The liquid crystalline phases formed by the molecules can be captured in the solid state by drying off solvent, resulting in solid nanopatterned (chemically and physically) thermally stable (to greater than 100 C) materials. Designed sequences which stabilize smectic phases have allowed a variety of nanoscale multilayered biopolymeric materials to be developed. Preliminary investigations suggest that chemical patterns running perpendicular to the smectic layer plane can be functionalized and used to localize a variety of organic, inorganic, and organometallic moieties in very simple multilayered nanocomposites. The phase behavior of collagen-like oligopeptide materials is described, emphasizing the correlation between mesophase, molecular orientation, and chemical patterning at the microscale and nanoscale. In many cases, the textures observed for smectic and hexatic phase collagens are remarkably similar to the complex (and not fully understood) helicoids observed in biological collagen-based tissues. Comparisons between biological morphologies and collagen model liquid crystalline (and solidified materials) textures may help us understand the molecular features which impart order and function to the extracellular matrix and to collagen-based mineralized tissues. Initial studies have utilized synthetic collagen-like peptides while future work will also focus on similar sequences generated via genetic engineering methods.

  11. Formation of amorphous materials

    DOEpatents

    Johnson, William L.; Schwarz, Ricardo B.

    1986-01-01

    Metastable amorphous or fine crystalline materials are formed by solid state reactions by diffusion of a metallic component into a solid compound or by diffusion of a gas into an intermetallic compound. The invention can be practiced on layers of metals deposited on an amorphous substrate or by intermixing powders with nucleating seed granules. All that is required is that the diffusion of the first component into the second component be much faster than the self-diffusion of the first component. The method is practiced at a temperature below the temperature at which the amorphous phase transforms into one or more crystalline phases and near or below the temperature at which the ratio of the rate of diffusion of the first component to the rate of self-diffusion is at least 10.sup.4. This anomalous diffusion criteria is found in many binary, tertiary and higher ordered systems of alloys and appears to be found in all alloy systems that form amorphous materials by rapid quenching. The method of the invention can totally convert much larger dimensional materials to amorphous materials in practical periods of several hours or less.

  12. Directing the phase behavior of polyelectrolyte complexes using chiral patterned peptides

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pacalin, Naomi M.; Leon, Lorraine; Tirrell, Matthew

    Polyelectrolyte complexes (PECs) have a broad range of promising applications as soft materials due to their self-assembly and diversity of structure and chemical composition. Peptide polymer PECs are highly biocompatible and biodegradable, making them particularly useful for encapsulation of food additives and flavors, micellar drug delivery, medical and underwater adhesives, fetal membrane patches, and scaffolds for cell growth in tissue engineering. While parameters affecting PEC formation and stability in regards to charge effects are well researched, little is known about the effects of van der Waals interactions, hydrogen bonding, and secondary structure in these materials. Peptide chirality provides a uniquemore » opportunity to manipulate PEC phase to modulate the amount of solid-like (precipitate) or liquid-like (coacervate) character by influencing hydrogen bonding interactions among peptide chains. In previous work, we showed that chiral peptides form solid complexes, while complexes with even one racemic peptide were fluid. This raised the interesting question of how long a homochiral sequence must be to result in solid phase formation. In this work, we designed chiral patterned peptides of polyglutamic acid and polylysine ranging from 50 to 90% L-chiral residues with increasing numbers of sequential L-chiral residues before a chirality change. These polymers were mixed together to form PECs. We observed that 8 or more sequential L-chiral residues are necessary to achieve both the appearance of a precipitate phase and sustained beta-sheets in the complex, as determined by optical imaging and FTIR Spectroscopy. Less homochiral content results in formation of a coacervate phase. Thus, we show that chiral sequence can be used to control the phase transition of PECs. Understanding how to manipulate PEC phase using chiral sequence as presented here may enable tuning of the material properties to achieve the desired mechanical strength for coatings and polymer brushes, or the most effective molecular release kinetics for drug delivery applications, for example.« less

  13. Directing the phase behavior of polyelectrolyte complexes using chiral patterned peptides

    NASA Astrophysics Data System (ADS)

    Pacalin, Naomi M.; Leon, Lorraine; Tirrell, Matthew

    2016-10-01

    Polyelectrolyte complexes (PECs) have a broad range of promising applications as soft materials due to their self-assembly and diversity of structure and chemical composition. Peptide polymer PECs are highly biocompatible and biodegradable, making them particularly useful for encapsulation of food additives and flavors, micellar drug delivery, medical and underwater adhesives, fetal membrane patches, and scaffolds for cell growth in tissue engineering. While parameters affecting PEC formation and stability in regards to charge effects are well researched, little is known about the effects of van der Waals interactions, hydrogen bonding, and secondary structure in these materials. Peptide chirality provides a unique opportunity to manipulate PEC phase to modulate the amount of solid-like (precipitate) or liquid-like (coacervate) character by influencing hydrogen bonding interactions among peptide chains. In previous work, we showed that chiral peptides form solid complexes, while complexes with even one racemic peptide were fluid. This raised the interesting question of how long a homochiral sequence must be to result in solid phase formation. In this work, we designed chiral patterned peptides of polyglutamic acid and polylysine ranging from 50 to 90% L-chiral residues with increasing numbers of sequential L-chiral residues before a chirality change. These polymers were mixed together to form PECs. We observed that 8 or more sequential L-chiral residues are necessary to achieve both the appearance of a precipitate phase and sustained β-sheets in the complex, as determined by optical imaging and FTIR Spectroscopy. Less homochiral content results in formation of a coacervate phase. Thus, we show that chiral sequence can be used to control the phase transition of PECs. Understanding how to manipulate PEC phase using chiral sequence as presented here may enable tuning of the material properties to achieve the desired mechanical strength for coatings and polymer brushes, or the most effective molecular release kinetics for drug delivery applications, for example.

  14. Quick and selective extraction of Z-ligustilide from Angelica sinensis using magnetic multiwalled carbon nanotubes.

    PubMed

    Zeng, Qiong; Jia, Yan-Wei; Xu, Pei-Li; Xiao, Meng-Wei; Liu, Yi-Ming; Peng, Shu-Lin; Liao, Xun

    2015-12-01

    A facile and highly efficient magnetic solid-phase extraction method has been developed for Z-ligustilide, the major therapeutic agent in Angelica sinensis. The solid-phase adsorbent material used was prepared by conjugating carbon nanotubes with magnetic Fe3 O4 nanoparticles via a hydrothermal reaction. The magnetic material showed a high affinity toward Z-ligustilide due to the π-π stacking interaction between the carbon nanotubes and Z-ligustilide, allowing a quick and selective exaction of Z-ligustilide from complex sample matrices. Factors influencing the magnetic solid-phase extraction such as the amount of the added adsorbent, adsorption and desorption time, and desorption solvent, were investigated. Due to its high extraction efficiency, this method was proved highly useful for sample cleanup/enrichment in quantitative high-performance liquid chromatography analysis. The proposed method had a linear calibration curve (R(2) = 0.9983) over the concentration between 4 ng/mL and 200 μg/mL Z-ligustilide. The accuracy of the method was determined by the recovery, which was from 92.07 to 104.02%, with the relative standard deviations >4.51%. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Dipole-Oriented Molecular Solids Can Undergo a Phase Change and Still Maintain Electrical Polarization

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cassidy, Andrew; Jørgensen, Mads R. V.; Rosu-Finsen, Alexander

    2016-10-02

    It has recently been demonstrated that nanoscale molecular films can spontaneously assemble to self-generate intrinsic electric fields that can exceed 10 8 V/m. These electric fields originate from polarization charges in the material that arise because the films self-assemble to orient molecular dipole moments. This has been called the spontelectric effect. Such growth of spontaneously polarized layers of molecular solids has implications for our understanding of how intermolecular interactions dictate the structure of molecular materials used in a range of applications, for example, molecular semiconductors, sensors, and catalysts. In this paper, we present the first in situ structural characterization ofmore » a representative spontelectric solid, nitrous oxide. Infrared spectroscopy, temperature-programmed desorption, and neutron reflectivity measurements demonstrate that polarized films of nitrous oxide undergo a structural phase transformation upon heating above 48 K. A mean-field model can be used to describe quantitatively the magnitude of the spontaneously generated field as a function of film-growth temperature, and this model also recreates the phase change. Finally, this reinforces the spontelectric model as a means of describing long-range dipole–dipole interactions and points to a new type of ordering in molecular thin films.« less

  16. Phase Transformation Induced Self-Healing Behavior of Al-Ag Alloy.

    PubMed

    Michalcová, Alena; Marek, Ivo; Knaislová, Anna; Sofer, Zdeněk; Vojtěch, Dalibor

    2018-01-27

    Self-healing alloys are promising materials that can decrease the consequences of accidents. To detect crack formation in a material is simple task that can be performed by e.g., sonic or ultrasound detection, but it is not always possible to immediately replace the damaged parts. In this situation, it is very advantageous to have the chance to heal the crack during operation, which can be done e.g., by annealing. In this paper, self-healing behavior was proven by TEM (Transmission electron microscope) observation of crack healing after annealing. The crack was observed in the rapidly solidified Al-30Ag alloy with non-equilibrium phase composition formed by a minor amount of Ag₂Al and a supersaturated solid solution of Ag in an fcc-Al matrix (fcc = face centered cubic). After annealing at 450 °C, equilibrium phase composition was obtained by forming a higher amount of Ag₂Al. This phase transformation did not allow the crack to be healed. Subsequent annealing at 550 °C caused recrystallization to a supersaturated solid solution of Ag in fcc-Al, followed by a return to the mixture of fcc-Al and Ag₂Al by cooling, and this process was accompanied by the closing of the crack. This observation proved the self-healing possibilities of the Ag₂Al phase. Practical application of this self-healing behavior could be achieved through the dispersion of fine Ag₂Al particles in a structural material, which will enrich the material with self-healing properties.

  17. Determination of Thermal Conductivity of Silicate Matrix for Applications in Effective Media Theory

    NASA Astrophysics Data System (ADS)

    Fiala, Lukáš; Jerman, Miloš; Reiterman, Pavel; Černý, Robert

    2018-02-01

    Silicate materials have an irreplaceable role in the construction industry. They are mainly represented by cement-based- or lime-based materials, such as concrete, cement mortar, or lime plaster, and consist of three phases: the solid matrix and air and water present in the pores. Therefore, their effective thermal conductivity depends on thermal conductivities of the involved phases. Due to the time-consuming experimental determination of the effective thermal conductivity, its calculation by means of homogenization techniques presents a reasonable alternative. In the homogenization theory, both volumetric content and particular property of each phase need to be identified. For porous materials the most problematic part is to accurately identify thermal conductivity of the solid matrix. Due to the complex composition of silicate materials, the thermal conductivity of the matrix can be determined only approximately, based on the knowledge of thermal conductivities of its major compounds. In this paper, the thermal conductivity of silicate matrix is determined using the measurement of a sufficiently large set of experimental data. Cement pastes with different open porosities are prepared, dried, and their effective thermal conductivity is determined using a transient heat-pulse method. The thermal conductivity of the matrix is calculated by means of extrapolation of the effective thermal conductivity versus porosity functions to zero porosity. Its practical applicability is demonstrated by calculating the effective thermal conductivity of a three-phase silicate material and comparing it with experimental data.

  18. A multi-scale Lattice Boltzmann model for simulating solute transport in 3D X-ray micro-tomography images of aggregated porous materials

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoxian; Crawford, John W.; Flavel, Richard J.; Young, Iain M.

    2016-10-01

    The Lattice Boltzmann (LB) model and X-ray computed tomography (CT) have been increasingly used in combination over the past decade to simulate water flow and chemical transport at pore scale in porous materials. Because of its limitation in resolution and the hierarchical structure of most natural soils, the X-ray CT tomography can only identify pores that are greater than its resolution and treats other pores as solid. As a result, the so-called solid phase in X-ray images may in reality be a grey phase, containing substantial connected pores capable of conducing fluids and solute. Although modified LB models have been developed to simulate fluid flow in such media, models for solute transport are relatively limited. In this paper, we propose a LB model for simulating solute transport in binary soil images containing permeable solid phase. The model is based on the single-relaxation time approach and uses a modified partial bounce-back method to describe the resistance caused by the permeable solid phase to chemical transport. We derive the relationship between the diffusion coefficient and the parameter introduced in the partial bounce-back method, and test the model against analytical solution for movement of a pulse of tracer. We also validate it against classical finite volume method for solute diffusion in a simple 2D image, and then apply the model to a soil image acquired using X-ray tomography at resolution of 30 μm in attempts to analyse how the ability of the solid phase to diffuse solute at micron-scale affects the behaviour of the solute at macro-scale after a volumetric average. Based on the simulated results, we discuss briefly the danger in interpreting experimental results using the continuum model without fully understanding the pore-scale processes, as well as the potential of using pore-scale modelling and tomography to help improve the continuum models.

  19. Methods of Fabricating a Layer of Metallic Glass-Based Material Using Immersion and Pouring Techniques

    NASA Technical Reports Server (NTRS)

    Hofmann, Douglas (Inventor)

    2015-01-01

    Systems and methods in accordance with embodiments of the invention implement layers of metallic glass-based materials. In one embodiment, a method of fabricating a layer of metallic glass includes: applying a coating layer of liquid phase metallic glass to an object, the coating layer being applied in a sufficient quantity such that the surface tension of the liquid phase metallic glass causes the coating layer to have a smooth surface; where the metallic glass has a critical cooling rate less than 1000 K/s; and cooling the coating layer of liquid phase metallic glass to form a layer of solid phase metallic glass.

  20. Jet formation in cerium metal to examine material strength

    DOE PAGES

    Jensen, B. J.; Cherne, F. J.; Prime, M. B.; ...

    2015-11-18

    Examining the evolution of material properties at extreme conditions advances our understanding of numerous high-pressure phenomena from natural events like meteorite impacts to general solid mechanics and fluid flow behavior. Some recent advances in synchrotron diagnostics coupled with dynamic compression platforms have introduced new possibilities for examining in-situ, spatially resolved material response with nanosecond time resolution. In this work, we examined jet formation from a Richtmyer-Meshkov instability in cerium initially shocked into a transient, high-pressure phase, and then released to a low-pressure, higher-temperature state. Cerium's rich phase diagram allows us to study the yield stress following a shock induced solid-solidmore » phase transition. X-ray imaging was used to obtain images of jet formation and evolution with 2–3 μm spatial resolution. And from these images, an analytic method was used to estimate the post-shock yield stress, and these results were compared to continuum calculations that incorporated an experimentally validated equation-of-state (EOS) for cerium coupled with a deviatoric strength model. Reasonable agreement was observed between the calculations and the data illustrating the sensitivity of jet formation on the yield stress values. Finally, the data and analysis shown here provide insight into material strength during dynamic loading which is expected to aid in the development of strength aware multi-phase EOS required to predict the response of matter at extreme conditions.« less

  1. A STUDY OF THE FEASIBILITY OF UTILIZING SOLID WASTES FOR BUILDING MATERIALS. PHASE III AND IV SUMMARY REPORTS

    EPA Science Inventory

    This report summarizes work to develop building materials containing inorganic and organic wastes and wastes-derived products. Attempts were made to produce full-scale products and qualify them for structural applications. Particle board panels were made of peanut hulls and wood ...

  2. Preparation of Paraffin@Poly(styrene-co-acrylic acid) Phase Change Nanocapsules via Combined Miniemulsion/Emulsion Polymerization.

    PubMed

    Zhang, Feng; Liu, Tian-Yu; Hou, Gui-Hua; Guan, Rong-Feng; Zhang, Jun-Hao

    2018-06-01

    The fast development of solid-liquid phase change materials calls for nanomaterials with large specific surface area for rapid heat transfer and encapsulation of phase change materials to prevent potential leakage. Here we report a combined miniemulsion/emulsion polymerization method to prepare poly(styrene-co-acrylic acid)-encapsulated paraffin (paraffin@P(St-co-AA)) nanocapsules. The method could suppress the shortcomings of common miniemulsion polymerization (such as evaporation of monomer and decomposition of initiator during ultrasonication). The paraffin@P(St-co-AA) nanocapsules are uniform in size and the polymer shell can be controlled by the weight ratio of St to paraffin. The phase change behavior of the nanocapsules is similar to that of pure paraffin. We believe our method can also be utilized to synthesize other core-shell phase change materials.

  3. Materials for high-temperature thermoelectric conversion

    NASA Technical Reports Server (NTRS)

    Feigelson, R. S.; Elwell, D.

    1983-01-01

    High boron materials of high efficiency for thermoelectric power generation and capable of prolonged operation at temperatures over 1200 C are discussed. Background theoretical studies indicated that the low carrier mobility of materials with beta boron and related structures is probably associated with the high density of traps. Experimental work was mainly concerned with silicon borides in view of promising data from European laboratories. A systematic study using structure determination and lattice constant measurements failed to confirm the existence of an SiBn phase. Only SiB6 and a solid solution of silicon in beta boron with a maximum solid solubility of 5.5-6 at % at 1650 C were found.

  4. Layered Lepidocrocite Type Structure Isolated by Revisiting the Sol–Gel Chemistry of Anatase TiO 2 : A New Anode Material for Batteries

    DOE PAGES

    Ma, Jiwei; Reeves, Kyle G.; Porras Gutierrez, Ana-Gabriela; ...

    2017-09-19

    Searches for new electrode materials for batteries must comply on financial and environmental costs to be useful in practical devices. The sol-gel chemistry has been widely used to design and implemented new concepts for the emergence of advanced materials such as hydride organic-inorganic composites. Here, we show that the simple reaction system including titanium alkoxide and water can be used to stabilize a new class of electrode materials. By investigating the crystallization path of anatase TiO2, an X-ray amorphous intermediate phase has been identified whose local structure probed by the pair distribution function, 1H solid-state NMR and DFT calculations, consistsmore » of a layered-type structure as found in the lepido-crocite. This phase presents the following general formula Ti 2-x⟂ xO 4-4x(OH) 4x.nH 2O (x ~ 0.5) where the substitution of oxide by hydroxide anions leads to the formation of titanium vacancies (•) and H 2O molecules are located in interlayers. Solid-state 1H NMR has enabled to characterize three main hydroxide environments that are Ti⟂-OH, Ti 2⟂ 2-OH and Ti3⟂-OH and layered H 2O molecules. The electrochemical properties of this phase were further investigated versus lithium and is shown to be very promising with reversible capacities of around 200 mAh.g -1 and an operating voltage of 1.55 V. We further showed that the lithium intercalation proceeds via a solid-solution mechanism. 7Li solid-state NMR and DFT calculations allowed to identify lithium host sites that are located at the titanium vacancies and interlayer space with lithium being solvated by structural water molecules. The easy fabrication, the absence of lithium and easier recycling and the encouraging properties makes this class of materials very attractive for competitive electrodes for batteries. We thus demonstrate that the revisit of an “old” chemistry with advanced characterization tools allows discovering new materials of technological relevance.« less

  5. Layered Lepidocrocite Type Structure Isolated by Revisiting the Sol–Gel Chemistry of Anatase TiO 2 : A New Anode Material for Batteries

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ma, Jiwei; Reeves, Kyle G.; Porras Gutierrez, Ana-Gabriela

    Searches for new electrode materials for batteries must comply on financial and environmental costs to be useful in practical devices. The sol-gel chemistry has been widely used to design and implemented new concepts for the emergence of advanced materials such as hydride organic-inorganic composites. Here, we show that the simple reaction system including titanium alkoxide and water can be used to stabilize a new class of electrode materials. By investigating the crystallization path of anatase TiO2, an X-ray amorphous intermediate phase has been identified whose local structure probed by the pair distribution function, 1H solid-state NMR and DFT calculations, consistsmore » of a layered-type structure as found in the lepido-crocite. This phase presents the following general formula Ti 2-x⟂ xO 4-4x(OH) 4x.nH 2O (x ~ 0.5) where the substitution of oxide by hydroxide anions leads to the formation of titanium vacancies (•) and H 2O molecules are located in interlayers. Solid-state 1H NMR has enabled to characterize three main hydroxide environments that are Ti⟂-OH, Ti 2⟂ 2-OH and Ti3⟂-OH and layered H 2O molecules. The electrochemical properties of this phase were further investigated versus lithium and is shown to be very promising with reversible capacities of around 200 mAh.g -1 and an operating voltage of 1.55 V. We further showed that the lithium intercalation proceeds via a solid-solution mechanism. 7Li solid-state NMR and DFT calculations allowed to identify lithium host sites that are located at the titanium vacancies and interlayer space with lithium being solvated by structural water molecules. The easy fabrication, the absence of lithium and easier recycling and the encouraging properties makes this class of materials very attractive for competitive electrodes for batteries. We thus demonstrate that the revisit of an “old” chemistry with advanced characterization tools allows discovering new materials of technological relevance.« less

  6. Solid-phase synthesis of molecularly imprinted nanoparticles.

    PubMed

    Canfarotta, Francesco; Poma, Alessandro; Guerreiro, Antonio; Piletsky, Sergey

    2016-03-01

    Molecularly imprinted polymers (MIPs) are synthetic materials, generally based on acrylic or methacrylic monomers, that are polymerized in the presence of a specific target molecule called the 'template' and capable of rebinding selectively to this target molecule. They have the potential to be low-cost and robust alternatives to biomolecules such as antibodies and receptors. When prepared by traditional synthetic methods (i.e., with free template in solution), their usefulness has been limited by high binding site heterogeneity, the presence of residual template and the fact that the production methods are complex and difficult to standardize. To overcome some of these limitations, we developed a method for the synthesis of MIP nanoparticles (nanoMIPs) using an innovative solid-phase approach, which relies on the covalent immobilization of the template molecules onto the surface of a solid support (glass beads). The obtained nanoMIPs are virtually free of template and demonstrate high affinity for the target molecule (e.g., melamine and trypsin in our published work). Because of an affinity separation step performed on the solid phase after polymerization, poor binders and unproductive polymer are removed, so the final product has more uniform binding characteristics. The overall protocol, starting from the immobilization of the template onto the solid phase and including the purification and characterization of the nanoparticles, takes up to 1 week.

  7. NiTi shape memory via solid-state nudge-elastic band

    NASA Astrophysics Data System (ADS)

    Zarkevich, Nikolai A.; Johnson, Duane D.

    2014-03-01

    We determine atomic mechanisms of the shape memory effect in NiTi from a generalized solid-state nudge elastic band (SSNEB) method. We consider transformation between the austenite B2 and the ground-state base-centered orthorhombic (BCO) structures. In these pathways we obtain the R-phase and discuss its structure. We confirm that BCO is the ground state, and determine the pathways to BCO martensite, which dictate transition barriers. While ideal B2 is unstable, we find a B2-like NiTi high-temperature solid phase with significant local displacement disorder, which is B2 on average. This B2-like phase appears to be entropically stabilized. This work is supported by the U.S. Department of Energy, Office of Basic Energy Science, Division of Materials Science and Engineering. Ames Laboratory is operated for the U.S. DOE by Iowa State University under contract DE-AC02-07CH11358.

  8. Shock response and phase transitions of MgO at planetary impact conditions

    DOE PAGES

    Root, Seth; Shulenburger, Luke; Lemke, Raymond W.; ...

    2015-11-04

    The moon-forming impact and the subsequent evolution of the proto-Earth is strongly dependent on the properties of materials at the extreme conditions generated by this violent collision. We examine the high pressure behavior of MgO, one of the dominant constituents in Earth’s mantle, using high-precision, plate impact shock compression experiments performed on Sandia National Laboratories’ Z Machine and extensive quantum calculations using density functional theory (DFT) and quantum Monte Carlo (QMC) methods. The combined data span from ambient conditions to 1.2 TPa and 42,000 K, showing solid-solid and solid-liquid phase boundaries. Furthermore our results indicate that under impact the solidmore » and liquid phases coexist for more than 100 GPa, pushing complete melting to pressures in excess of 600 GPa. Furthermore, the high pressure required for complete shock melting has implications for a broad range of planetary collision events.« less

  9. Chirality-selected phase behaviour in ionic polypeptide complexes

    DOE PAGES

    Perry, Sarah L.; Leon, Lorraine; Hoffmann, Kyle Q.; ...

    2015-01-14

    In this study, polyelectrolyte complexes present new opportunities for self-assembled soft matter. Factors determining whether the phase of the complex is solid or liquid remain unclear. Ionic polypeptides enable examination of the effects of stereochemistry on complex formation. Here we demonstrate that chirality determines the state of polyelectrolyte complexes, formed from mixing dilute solutions of oppositely charged polypeptides, via a combination of electrostatic and hydrogen-bonding interactions. Fluid complexes occur when at least one of the polypeptides in the mixture is racemic, which disrupts backbone hydrogen-bonding networks. Pairs of purely chiral polypeptides, of any sense, form compact, fibrillar solids with amore » β-sheet structure. Analogous behaviour occurs in micelles formed from polypeptide block copolymers with polyethylene oxide, where assembly into aggregates with either solid or fluid cores, and eventually into ordered phases at high concentrations, is possible. Chirality is an exploitable tool for manipulating material properties in polyelectrolyte complexation.« less

  10. Scientific support for an orbiter middeck experiment on solid surface combustion

    NASA Technical Reports Server (NTRS)

    Altenkirch, Robert A.; Vedha-Nayagam, M.; Srikantaiah, Nataraj

    1988-01-01

    The objective is to determine the mechanism of gas-phase flame spread over solid fuel surfaces in the absence of any buoyancy or externally imposed gas-phase flow. Such understanding can be used to improve the fire safety aspects of space travel by providing information that will allow judicious selections of spacecraft materials and environments to be made. The planned experiment consists of measuring the flame spread rate over thermally thin and thermally thick fuels in a closed container in the low-gravity environment of the Space Shuttle. Measurements consist of flame spread rate and shape obtained from two views of the process as recorded on movie film and surface and gas-phase temperatures obtained from fine-wire thermocouples. The temperature measurements along with appropriate modeling provide information about the gas-to-solid heat flux. Environmental parameters to be varied are the oxygen concentration and pressure.

  11. Reversible temperature regulation of electrical and thermal conductivity using liquid–solid phase transitions

    PubMed Central

    Zheng, Ruiting; Gao, Jinwei; Wang, Jianjian; Chen, Gang

    2011-01-01

    Reversible temperature tuning of electrical and thermal conductivities of materials is of interest for many applications, including seasonal regulation of building temperature, thermal storage and sensors. Here we introduce a general strategy to achieve large contrasts in electrical and thermal conductivities using first-order phase transitions in percolated composite materials. Internal stress generated during a phase transition modulates the electrical and thermal contact resistances, leading to large contrasts in the electrical and thermal conductivities at the phase transition temperature. With graphite/hexadecane suspensions, the electrical conductivity changes 2 orders of magnitude and the thermal conductivity varies up to 3.2 times near 18 °C. The generality of the approach is also demonstrated in other materials such as graphite/water and carbon nanotube/hexadecane suspensions. PMID:21505445

  12. Reversible temperature regulation of electrical and thermal conductivity using liquid-solid phase transitions.

    PubMed

    Zheng, Ruiting; Gao, Jinwei; Wang, Jianjian; Chen, Gang

    2011-01-01

    Reversible temperature tuning of electrical and thermal conductivities of materials is of interest for many applications, including seasonal regulation of building temperature, thermal storage and sensors. Here we introduce a general strategy to achieve large contrasts in electrical and thermal conductivities using first-order phase transitions in percolated composite materials. Internal stress generated during a phase transition modulates the electrical and thermal contact resistances, leading to large contrasts in the electrical and thermal conductivities at the phase transition temperature. With graphite/hexadecane suspensions, the electrical conductivity changes 2 orders of magnitude and the thermal conductivity varies up to 3.2 times near 18 °C. The generality of the approach is also demonstrated in other materials such as graphite/water and carbon nanotube/hexadecane suspensions.

  13. Cooling apparatus and couplings therefor

    NASA Technical Reports Server (NTRS)

    Lomax, Curtis (Inventor); Webbon, Bruce (Inventor)

    1993-01-01

    The present invention relates generally to the field of thermal transfer and, more specifically, to a direct-interface, fusible heat sink for non-venting, regenerable, and self-contained thermal regulation. A quick connect coupling includes a male and a female portion. The female portion is frozen in a container of solid-phase coolant fluid, i.e., water, so that passages in the housing are blocked by ice initially. The ice is melted by direct interface with liquid coolant fluid delivered from the male portion. The present invention has advantages in that the phase change material remains sealed at all times, including during regeneration. Also, it uses quick-disconnect couplings that allow the phase change material to completely fill the container and is easily handled in microgravity without spills, leakage, or handling of phase change material.

  14. Segmented nanowires displaying locally controllable properties

    DOEpatents

    Sutter, Eli Anguelova; Sutter, Peter Werner

    2013-03-05

    Vapor-liquid-solid growth of nanowires is tailored to achieve complex one-dimensional material geometries using phase diagrams determined for nanoscale materials. Segmented one-dimensional nanowires having constant composition display locally variable electronic band structures that are determined by the diameter of the nanowires. The unique electrical and optical properties of the segmented nanowires are exploited to form electronic and optoelectronic devices. Using gold-germanium as a model system, in situ transmission electron microscopy establishes, for nanometer-sized Au--Ge alloy drops at the tips of Ge nanowires (NWs), the parts of the phase diagram that determine their temperature-dependent equilibrium composition. The nanoscale phase diagram is then used to determine the exchange of material between the NW and the drop. The phase diagram for the nanoscale drop deviates significantly from that of the bulk alloy.

  15. Method and apparatus for optimized sampling of volatilizable target substances

    DOEpatents

    Lindgren, Eric R.; Phelan, James M.

    2004-10-12

    An apparatus for capturing, from gases such as soil gas, target analytes. Target analytes may include emanations from explosive materials or from residues of explosive materials. The apparatus employs principles of sorption common to solid phase microextraction, and is best used in conjunction with analysis means such as a gas chromatograph. To sorb target analytes, the apparatus functions using various sorptive structures to capture target analyte. Depending upon the embodiment, those structures may include a capillary tube including an interior surface on which sorptive material (similar to that on the surface of a SPME fiber) is supported (along with means for moving gases through the capillary tube so that the gases come into close proximity to the sorptive material). In one disclosed embodiment, at least one such sorptive structure is associated with an enclosure including an opening in communication with the surface of a soil region potentially contaminated with buried explosive material such as unexploded ordnance. Emanations from explosive materials can pass into and accumulate in the enclosure where they are sorbed by the sorptive structures. Also disclosed is the use of heating means such as microwave horns to drive target analytes into the soil gas from solid and liquid phase components of the soil.

  16. MaRIE first experiments summaries version: May 9, 2010

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sarrao, John L

    2010-01-01

    A predictive understanding of microstructure-based heterogeneity and its consequences for materials damage & failure and phase transformation initiation is presently lacking. Most metallic materials used in applications are polycrystalline aggregates - individual single crystals separated by grain boundaries. Most of these materials are either metallic alloys or contain impurities. In either case, there is spatial variability in their chemical composition. These materials also contain dislocations which will be distributed in some way throughout the individual grains and increase in density with deformation and typically form dislocation sub-cell arrangements - producing spatial distribution in dislocation density. Many materials also produce twinmore » or slip band structures with deformation which produce further heterogeneity within individual crystals. The objective of this first experiment is to probe the physics of dynamic solid-solid phase transformation and damage at length scales approaching those at which they nucleate in order to gain a detailed understanding of this process and the influence real material microstructure has on these events. These experiments would simultaneously be simulated by the appropriate modeling tools to further develop these predictive tools and to assist in our interpretation of experimental results.« less

  17. Phased Array Approach To Retrieve Gases, Liquids, Or Solids From Subsurface And Subaqueous Geologic Or Man-Made Formations

    DOEpatents

    Rynne, Timothy M.; Spadaro, John F.; Iovenitti, Joe L.; Dering, John P.; Hill, Donald G.

    1998-10-27

    A method of enhancing the remediation of contaminated soils and ground water, production of oil and gas, and production of any solid, gas, and/or liquid from subsurface geologic and man-made formations including the steps of estimating the geometric boundaries of the region containing the material to be recovered, drilling a recovery well(s) into subsurface in a strategic location to recover the material of interest, establishing multiple sources of acoustical power in an array about and spaced-apart from the surface or at various depths below the surface in a borehole(s) and/or well(s), directing a volume of acoustical excitation from the sources into the region containing the material to be recovered, the excitation in the form of either controllable sinusoidal, square, pulsed, or various combinations of these three waveforms, and controlling the phasing, frequency, power, duration, and direction of these waveforms from the sources to increase and control the intensity of acoustical excitation in the region of the material to be recovered to enhance. the recovery of said material from the recovery well(s). The invention will augment any technology affecting the removal of materials from the subsurface.

  18. Large effect of membrane tension on the fluid-solid phase transitions of two-component phosphatidylcholine vesicles.

    PubMed

    Chen, Dong; Santore, Maria M

    2014-01-07

    Model phospholipid membranes and vesicles have long provided insight into the nature of confined materials and membranes while also providing a platform for drug delivery. The rich thermodynamic behavior and interesting domain shapes in these membranes have previously been mapped in extensive studies that vary temperature and composition; however, the thermodynamic impact of tension on bilayers has been restricted to recent reports of subtly reduced fluid-fluid transition temperatures. In two-component phosphatidylcholine unilamellar vesicles [1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)], we report a dramatic influence of tension on the fluid-solid transition and resulting phases: At fixed composition, systematic variations in tension produce differently shaped solid domains (striped or irregular hexagons), shift fluid-solid transition temperatures, and produce a triple-point-like intersection of coexistence curves at elevated tensions, about 3 mN/m for 30% DOPC/70% DPPC. Tension therefore represents a potential switch of microstructure in responsive engineered materials; it is an important morphology-determining variable in confined systems, and, in biological membranes, it may provide a means to regulate dynamic structure.

  19. Important aspects in the formulation of solid-fluid debris-flow models. Part I. Thermodynamic implications

    NASA Astrophysics Data System (ADS)

    Hutter, Kolumban; Schneider, Lukas

    2010-06-01

    This article points at some critical issues which are connected with the theoretical formulation of the thermodynamics of solid-fluid mixtures of frictional materials. It is our view that a complete thermodynamic exploitation of the second law of thermodynamics is necessary to obtain the proper parameterizations of the constitutive quantities in such theories. These issues are explained in detail in a recently published book by Schneider and Hutter (Solid-Fluid Mixtures of Frictional Materials in Geophysical and Geotechnical Context, 2009), which we wish to advertize with these notes. The model is a saturated mixture of an arbitrary number of solid and fluid constituents which may be compressible or density preserving, which exhibit visco-frictional (visco-hypoplastic) behavior, but are all subject to the same temperature. Mass exchange between the constituents may account for particle size separation and phase changes due to fragmentation and abrasion. Destabilization of a saturated soil mass from the pre- and the post-critical phases of a catastrophic motion from initiation to deposition is modeled by symmetric tensorial variables which are related to the rate independent parts of the constituent stress tensors.

  20. Chemistry and Evolution of Interstellar Clouds

    NASA Technical Reports Server (NTRS)

    Wooden, D. H.; Charnley, S. B.; Ehrenfreund, P.

    2003-01-01

    In this chapter we describe how elements have been and are still being formed in the galaxy and how they are transformed into the reservoir of materials present at the time of formation of our protosolar nebula. We discuss the global cycle of matter, beginning at its formation site in stars, where it is ejected through winds and explosions into the diffuse interstellar medium. In the next stage of the global cycle occurs in cold, dense molecular clouds, where the complexity of molecules and ices increases relative to the diffuse ISM.. When a protostar forms in a dense core within a molecular cloud, it heats the surrounding infalling matter warms and releases molecules from the solid phase into the gas phase in a warm, dense core, sponsoring a rich gas-phase chemistry. Some material from the cold and warm regions within molecular clouds probably survives as interstellar matter in the protostellar disk. For the diffuse ISM, for cold, dense clouds, and for dense-warm cores, the physio-chemical processes that occur within the gas and solid phases are discussed in detail.

  1. Overview of the Tusas Code for Simulation of Dendritic Solidification

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Trainer, Amelia J.; Newman, Christopher Kyle; Francois, Marianne M.

    2016-01-07

    The aim of this project is to conduct a parametric investigation into the modeling of two dimensional dendrite solidification, using the phase field model. Specifically, we use the Tusas code, which is for coupled heat and phase-field simulation of dendritic solidification. Dendritic solidification, which may occur in the presence of an unstable solidification interface, results in treelike microstructures that often grow perpendicular to the rest of the growth front. The interface may become unstable if the enthalpy of the solid material is less than that of the liquid material, or if the solute is less soluble in solid than itmore » is in liquid, potentially causing a partition [1]. A key motivation behind this research is that a broadened understanding of phase-field formulation and microstructural developments can be utilized for macroscopic simulations of phase change. This may be directly implemented as a part of the Telluride project at Los Alamos National Laboratory (LANL), through which a computational additive manufacturing simulation tool is being developed, ultimately to become part of the Advanced Simulation and Computing Program within the U.S. Department of Energy [2].« less

  2. Carbon and Sulfur Isotopic Composition of Rocknest Soil as Determined with the Sample Analysis at Mars(SAM) Quadrupole Mass Spectrometer

    NASA Technical Reports Server (NTRS)

    Franz, H. B.; McAdam, C.; Stern, J. C.; Archer, P. D., Jr.; Sutter, B.; Grotzinger, J. P.; Jones, J. H.; Leshin, L. A.; Mahaffy, P. R.; Ming, D. W.; hide

    2013-01-01

    The Sample Analysis at Mars (SAM) instrument suite on the Mars Science Laboratory (MSL) Curiosity rover got its first taste of solid Mars in the form of loose, unconsolidated materials (soil) acquired from an aeolian bedform designated Rocknest. Evolved gas analysis (EGA) revealed the presence of H2O as well as O-, C- and S-bearing phases in these samples. CheMin did not detect crystalline phases containing these gaseous species but did detect the presence of X-ray amorphous materials. In the absence of definitive mineralogical identification by CheMin, SAM EGA data can provide clues to the nature and/or mineralogy of volatile-bearing phases through examination of temperatures at which gases are evolved from solid samples. In addition, the isotopic composition of these gases, particularly when multiple sources contribute to a given EGA curve, may be used to identify possible formation scenarios and relationships between phases. Here we report C and S isotope ratios for CO2 and SO2 evolved from Rocknest soil samples as measured with SAM's quadrupole mass spectrometer (QMS).

  3. Combination of sorption properties of polydimethylsiloxane and solid-phase extraction sorbents in a single composite material for the passive sampling of polar and apolar pesticides in water.

    PubMed

    Martin, Alexis; Margoum, Christelle; Coquery, Marina; Randon, Jérôme

    2016-10-01

    Passive sampling techniques have been developed as an alternative method for in situ integrative monitoring of trace levels of neutral pesticides in environmental waters. The objective of this work was to develop a new receiving phase for pesticides with a wide range of polarities in a single step. We describe the development of three new composite silicone rubbers, combining polydimethylsiloxane mechanical and sorption properties with solid-phase extraction sorbents, prepared as a receiving phase for passive sampling. A composite silicone rubber composed of polydimethylsiloxane/poly(divinylbenzene-co-N-vinylpyrrolidone) was selected by batch experiments for its high sorption properties for pesticides with octanol-water partition coefficients ranging from 2.3 to 5.5. We named this composite material "Polar/Apolar Composite Silicone Rubber". A structural study by scanning electron microscopy confirmed the homogeneous dispersion of the sorbent particles and the encapsulation of particles within the polydimethylsiloxane matrix. We also demonstrate that this composite material is resistant to common solvents used for the back-extraction of analytes and has a maximal resistance temperature of 350°C. Therefore, the characteristics of the "Polar/Apolar Composite Silicone Rubber" meet most of the criteria for use as a receiving phase for the passive sampling of pesticides. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Morphological and Electrochemical Characterization of Nanostructured Li 4Ti 5O 12 Electrodes Using Multiple Imaging Mode Synchrotron X-ray Computed Tomography

    DOE PAGES

    Kashkooli, Ali Ghorbani; Foreman, Evan; Farhad, Siamak; ...

    2017-09-21

    In this study, synchrotron X-ray computed tomography has been utilized using two different imaging modes, absorption and Zernike phase contrast, to reconstruct the real three-dimensional (3D) morphology of nanostructured Li 4Ti 5O 12 (LTO) electrodes. The morphology of the high atomic number active material has been obtained using the absorption contrast mode, whereas the percolated solid network composed of active material and carbon-doped polymer binder domain (CBD) has been obtained using the Zernike phase contrast mode. The 3D absorption contrast image revealed that some LTO nano-particles tend to agglomerate and form secondary micro-sized particles with varying degrees of sphericity. Themore » tortuosity of electrode’s pore and solid phases were found to have directional dependence, different from Bruggeman’s tortuosity commonly used in macro-homogeneous models. The electrode’s heterogeneous structure was investigated by developing a numerical model to simulate galvanostatic discharge process using the Zernike phase contrast mode. The inclusion of CBD in the Zernike phase contrast results in an integrated percolated network of active material and CBD that is highly suited for continuum modeling. As a result, the simulation results highlight the importance of using the real 3D geometry since the spatial distribution of physical and electrochemical properties have a strong non-uniformity due to microstructural heterogeneities.« less

  5. Surface-modified multifunctional MIP nanoparticles

    NASA Astrophysics Data System (ADS)

    Moczko, Ewa; Poma, Alessandro; Guerreiro, Antonio; Perez de Vargas Sansalvador, Isabel; Caygill, Sarah; Canfarotta, Francesco; Whitcombe, Michael J.; Piletsky, Sergey

    2013-04-01

    The synthesis of core-shell molecularly imprinted polymer nanoparticles (MIP NPs) has been performed using a novel solid-phase approach on immobilised templates. The same solid phase also acts as a protective functionality for high affinity binding sites during subsequent derivatisation/shell formation. This procedure allows for the rapid synthesis, controlled separation and purification of high-affinity materials, with each production cycle taking just 2 hours. The aim of this approach is to synthesise uniformly sized imprinted materials at the nanoscale which can be readily grafted with various polymers without affecting their affinity and specificity. For demonstration purposes we grafted anti-melamine MIP NPs with coatings which introduce the following surface characteristics: high polarity (PEG methacrylate); electro-activity (vinylferrocene); fluorescence (eosin acrylate); thiol groups (pentaerythritol tetrakis(3-mercaptopropionate)). The method has broad applicability and can be used to produce multifunctional imprinted nanoparticles with potential for further application in the biosensors, diagnostics and biomedical fields and as an alternative to natural receptors.The synthesis of core-shell molecularly imprinted polymer nanoparticles (MIP NPs) has been performed using a novel solid-phase approach on immobilised templates. The same solid phase also acts as a protective functionality for high affinity binding sites during subsequent derivatisation/shell formation. This procedure allows for the rapid synthesis, controlled separation and purification of high-affinity materials, with each production cycle taking just 2 hours. The aim of this approach is to synthesise uniformly sized imprinted materials at the nanoscale which can be readily grafted with various polymers without affecting their affinity and specificity. For demonstration purposes we grafted anti-melamine MIP NPs with coatings which introduce the following surface characteristics: high polarity (PEG methacrylate); electro-activity (vinylferrocene); fluorescence (eosin acrylate); thiol groups (pentaerythritol tetrakis(3-mercaptopropionate)). The method has broad applicability and can be used to produce multifunctional imprinted nanoparticles with potential for further application in the biosensors, diagnostics and biomedical fields and as an alternative to natural receptors. Electronic supplementary information (ESI) available: Details of the synthesis of eosin O-acrylate monomer and 1H-NMR spectrum of MIP NPs post-derivatised with PEG shell. See DOI: 10.1039/c3nr00354j

  6. Preparative isolation of flavonoid glycosides from Sphaerophysa salsula using hydrophilic interaction solid-phase extraction coupled with two-dimensional preparative liquid chromatography.

    PubMed

    Jiao, Lijin; Tao, Yanduo; Wang, Weidong; Shao, Yun; Mei, Lijuan; Wang, Qilan; Dang, Jun

    2017-10-01

    An offline preparative two-dimensional reversed-phase liquid chromatography/hydrophilic interaction liquid chromatography coupled with hydrophilic interaction solid-phase extraction method was developed for the preparative isolation of flavonoid glycosides from a crude sample of Sphaerophysa salsula. First, the non-flavonoids were removed using an XAmide solid-phase extraction cartridge. Based on the separation results of three different chromatographic stationary phases, the first-dimensional preparation was performed on an XAqua C18 prep column, and 15 fractions were obtained from the 5.2 g target sample. Then, three representative fractions were selected for additional purification on an XAmide preparative column to further isolate the flavonoid glycosides. In all, eight flavonoid glycosides were isolated in purities over 97%. The results demonstrated that the two-dimensional liquid chromatography method used in this study was effective for the preparative separation of flavonoid glycosides from Sphaerophysa salsula. Additionally, this method showed great potential for the separation of flavonoid glycosides from other plant materials. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Formation of sodium bismuth titanate-barium titanate during solid-state synthesis

    DOE PAGES

    Hou, Dong; Aksel, Elena; Fancher, Chris M.; ...

    2017-01-12

    Phase formation of sodium bismuth titanate (Na 0.5Bi 0.5TiO 3 or NBT) and its solid solution with barium titanate (BaTiO 3 or BT) during the calcination process is studied using in situ high-temperature diffraction. The reactant powders were mixed and heated to 1000°C, while X-ray diffraction patterns were recorded continuously. Phase evolutions from starting materials to final perovskite products are observed, and different transient phases are identified. The formation mechanism of NBT and NBT–xBT perovskite structures is discussed, and a reaction sequence is suggested based on the observations. The in situ study leads to a new processing approach, which ismore » the use of nano-TiO 2, and gives insights to the particle size effect for solid-state synthesis products. Lastly, it was found that the use of nano-TiO 2 as reactant powder accelerates the synthesis process, decreases the formation of transient phases, and helps to obtain phase-pure products using a lower thermal budget.« less

  8. A new carbon-based magnetic material for the dispersive solid-phase extraction of UV filters from water samples before liquid chromatography-tandem mass spectrometry analysis.

    PubMed

    Piovesana, Susy; Capriotti, Anna Laura; Cavaliere, Chiara; La Barbera, Giorgia; Samperi, Roberto; Zenezini Chiozzi, Riccardo; Laganà, Aldo

    2017-07-01

    Magnetic solid-phase extraction is one of the most promising new extraction methods for liquid samples before ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis. Several types of materials, including carbonaceous ones, have been prepared for this purpose. In this paper, for the first time, the preparation, characterization, and sorption capability of Fe 3 O 4 -graphitized carbon black (mGCB) composite toward some compounds of environmental interest were investigated. The synthesized mGCB consisted of micrometric GCB particles with 55 m 2  g -1 surface area bearing some carbonyl and hydroxyl functionalities and the surface partially decorated by Fe 3 O 4 microparticles. The prepared mGCB was firstly tested as an adsorbent for the extraction from surface water of 50 pollutants, including estrogens, perfluoroalkyl compounds, UV filters, and quinolones. The material showed good affinity to many of the tested compounds, except carboxylates and glucoronates; however, some compounds were difficult to desorb. Ten UV filters belonging to the chemical classes of benzophenones and p-aminobenzoates were selected, and parameters were optimized for the extraction of these compounds from surface water before UHPLC-MS/MS determination. Then, the method was validated in terms of linearity, trueness, intra-laboratory precision, and detection and quantification limits. In summary, the method performance (trueness, expressed as analytical recovery, 85-114%; RSD 5-15%) appears suitable for the determination of the selected compounds at the level of 10-100 ng L -1 , with detection limits in the range of 1-5 ng L -1 . Finally, the new method was compared with a published one, based on conventional solid-phase extraction with GCB, showing similar performance in real sample analysis. Graphical Abstract Workflow of the analytical method based on magnetic solid-phase extraction followed by LC-MS/MS determination.

  9. Evaluation of ionic liquids supported on silica as a sorbent for fully automated online solid-phase extraction with LC-MS determination of sulfonamides in bovine milk samples.

    PubMed

    da Silva, Meire Ribeiro; Mauro Lanças, Fernando

    2018-03-10

    Sulfonamides are antibiotics widely used in the treatment of diseases in dairy cattle. However, their indiscriminate use for disease control may lead to their presence in tissues and milk and their determination requires a sample preparation step as part of an analytical approach. Among the several sample preparation techniques available, those based upon the use of sorptive materials have been widely employed. Recently, the application of ionic liquids immobilized on silica surfaces or polymeric materials has been evaluated for such an application. This manuscript addresses the evaluation of silica-based ionic liquid obtained by a sol-gel synthesis process by basic catalysis as sorbent for online solid-phase extraction with liquid chromatography and electrospray ionization time-of-flight mass spectrometry for sulfonamides determination. Infrared vibrational spectroscopy confirmed the presence of the ionic liquid on the silica surface, suggesting that the ionic liquid was anchored on to the silica surface. Other sorbents varying the ionic liquid alkyl chain were also synthesized and evaluated by off-line solid-phase extraction in the sulfonamide extraction. As the length of the alkyl chain increased, the amount of extracted sulfonamides decreased, possibly due to a decrease in the electrostatic interaction caused by the reduction in the polarity, as well as the presence of a hexafluorophosphate anion that increases the hydrophobic character of the material. The use of 1-butyl-3-methylimidazolium hexafluorophosphate as a selective ionic liquid sorbent enabled the isolation and sulfonamide preconcentration in bovine milk by online solid-phase extraction with liquid chromatography and electrospray ionization time-of-flight mass spectrometry. The limit of quantification for the method developed was 5-7, 5 μg/mL, with extraction recoveries ranging between 74 and 93% and intra- and interassay between 1.5-12.5 and 2.3-13.1, respectively. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Theoretical calculating the thermodynamic properties of solid sorbents for CO{sub 2} capture applications

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Duan, Yuhua

    2012-11-02

    Since current technologies for capturing CO{sub 2} to fight global climate change are still too energy intensive, there is a critical need for development of new materials that can capture CO{sub 2} reversibly with acceptable energy costs. Accordingly, solid sorbents have been proposed to be used for CO{sub 2} capture applications through a reversible chemical transformation. By combining thermodynamic database mining with first principles density functional theory and phonon lattice dynamics calculations, a theoretical screening methodology to identify the most promising CO{sub 2} sorbent candidates from the vast array of possible solid materials has been proposed and validated. The calculatedmore » thermodynamic properties of different classes of solid materials versus temperature and pressure changes were further used to evaluate the equilibrium properties for the CO{sub 2} adsorption/desorption cycles. According to the requirements imposed by the pre- and post- combustion technologies and based on our calculated thermodynamic properties for the CO{sub 2} capture reactions by the solids of interest, we were able to screen only those solid materials for which lower capture energy costs are expected at the desired pressure and temperature conditions. Only those selected CO{sub 2} sorbent candidates were further considered for experimental validations. The ab initio thermodynamic technique has the advantage of identifying thermodynamic properties of CO{sub 2} capture reactions without any experimental input beyond crystallographic structural information of the solid phases involved. Such methodology not only can be used to search for good candidates from existing database of solid materials, but also can provide some guidelines for synthesis new materials. In this presentation, we first introduce our screening methodology and the results on a testing set of solids with known thermodynamic properties to validate our methodology. Then, by applying our computational method to several different kinds of solid systems, we demonstrate that our methodology can predict the useful information to help developing CO{sub 2} capture Technologies.« less

  11. Evaluating structure selection in the hydrothermal growth of FeS 2 pyrite and marcasite

    DOE PAGES

    Kitchaev, Daniil A.; Ceder, Gerbrand

    2016-12-14

    While the ab initio prediction of the properties of solids and their optimization towards new proposed materials is becoming established, little predictive theory exists as to which metastable materials can be made and how, impeding their experimental realization. Here we propose a quasi-thermodynamic framework for predicting the hydrothermal synthetic accessibility of metastable materials and apply this model to understanding the phase selection between the pyrite and marcasite polymorphs of FeS 2. We demonstrate that phase selection in this system can be explained by the surface stability of the two phases as a function of ambient pH within nano-size regimes relevantmore » to nucleation. This result suggests that a first-principles understanding of nano-size phase stability in realistic synthesis environments can serve to explain or predict the synthetic accessibility of structural polymorphs, providing a guideline to experimental synthesis via efficient computational materials design.« less

  12. Releasing metal catalysts via phase transition: (NiO)0.05-(SrTi0.8Nb0.2O3)0.95 as a redox stable anode material for solid oxide fuel cells.

    PubMed

    Xiao, Guoliang; Wang, Siwei; Lin, Ye; Zhang, Yanxiang; An, Ke; Chen, Fanglin

    2014-11-26

    Donor-doped perovskite-type SrTiO3 experiences stoichiometric changes at high temperatures in different Po2 involving the formation of Sr or Ti-rich impurities. NiO is incorporated into the stoichiometric strontium titanate, SrTi0.8Nb0.2O3-δ (STN), to form an A-site deficient perovskite material, (NiO)0.05-(SrTi0.8Nb0.2O3)0.95 (Ni-STN), for balancing the phase transition. Metallic Ni nanoparticles can be released upon reduction instead of forming undesired secondary phases. This material design introduces a simple catalytic modification method with good compositional control of the ceramic backbones, by which transport property and durability of solid oxide fuel cell anodes are largely determined. Using Ni-STN as anodes for solid oxide fuel cells, enhanced catalytic activity and remarkable stability in redox cycling have been achieved. Electrolyte-supported cells with the cell configuration of Ni-STN-SDC anode, La0.8Sr0.2Ga0.87Mg0.13O3 (LSGM) electrolyte, and La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) cathode produce peak power densities of 612, 794, and 922 mW cm(-2) at 800, 850, and 900 °C, respectively, using H2 as the fuel and air as the oxidant. Minor degradation in fuel cell performance resulted from redox cycling can be recovered upon operating the fuel cells in H2. Such property makes Ni-STN a promising regenerative anode candidate for solid oxide fuel cells.

  13. A finite difference method for a coupled model of wave propagation in poroelastic materials.

    PubMed

    Zhang, Yang; Song, Limin; Deffenbaugh, Max; Toksöz, M Nafi

    2010-05-01

    A computational method for time-domain multi-physics simulation of wave propagation in a poroelastic medium is presented. The medium is composed of an elastic matrix saturated with a Newtonian fluid, and the method operates on a digital representation of the medium where a distinct material phase and properties are specified at each volume cell. The dynamic response to an acoustic excitation is modeled mathematically with a coupled system of equations: elastic wave equation in the solid matrix and linearized Navier-Stokes equation in the fluid. Implementation of the solution is simplified by introducing a common numerical form for both solid and fluid cells and using a rotated-staggered-grid which allows stable solutions without explicitly handling the fluid-solid boundary conditions. A stability analysis is presented which can be used to select gridding and time step size as a function of material properties. The numerical results are shown to agree with the analytical solution for an idealized porous medium of periodically alternating solid and fluid layers.

  14. From Two-Phase to Three-Phase: The New Electrochemical Interface by Oxide Electrocatalysts

    NASA Astrophysics Data System (ADS)

    Xu, Zhichuan J.

    2018-03-01

    Electrochemical reactions typically occur at the interface between a solid electrode and a liquid electrolyte. The charge exchange behaviour between these two phases determines the kinetics of electrochemical reactions. In the past few years, significant advances have been made in the development of metal oxide electrocatalysts for fuel cell and electrolyser reactions. However, considerable gaps remain in the fundamental understanding of the charge transfer pathways and the interaction between the metal oxides and the conducting substrate on which they are located. In particular, the electrochemical interfaces of metal oxides are significantly different from the traditional (metal) ones, where only a conductive solid electrode and a liquid electrolyte are considered. Oxides are insulating and have to be combined with carbon as a conductive mediator. This electrode configuration results in a three-phase electrochemical interface, consisting of the insulating oxide, the conductive carbon, and the liquid electrolyte. To date, the mechanistic insights into this kind of non-traditional electrochemical interface remain unclear. Consequently conventional electrochemistry concepts, established on classical electrode materials and their two-phase interfaces, are facing challenges when employed for explaining these new electrode materials. [Figure not available: see fulltext.

  15. Melt coaxial electrospinning: a versatile method for the encapsulation of solid materials and fabrication of phase change nanofibers.

    PubMed

    McCann, Jesse T; Marquez, Manuel; Xia, Younan

    2006-12-01

    We have developed a method based on melt coaxial electrospinning for fabricating phase change nanofibers consisting of long-chain hydrocarbon cores and composite sheaths. This method combines melt electrospinning with a coaxial spinneret and allows for nonpolar solids such as paraffins to be electrospun and encapsulated in one step. Shape-stabilized, phase change nanofibers have many potential applications as they are able to absorb, hold, and release large amounts of thermal energy over a certain temperature range by taking advantage of the large heat of fusion of long-chain hydrocarbons. We have focused on compounds with melting points near room temperature (octadecane) and body temperature (eicosane) as these temperature ranges are most valuable in practice. We have produced thermally stable, phase change materials up to 45 wt % octadecane, as measured by differential scanning calorimetry. In addition, the resultant fibers display novel segmented morphologies for the cores due to the rapid solidification of the hydrocarbons driven by evaporative cooling of the carrier solution. Aside from the fabrication of phase change nanofibers, the melt coaxial method is promising for applications related to microencapsulation and controlled release of drugs.

  16. Molecular Modeling of Three Phase Contact for Static and Dynamic Contact Angle Phenomena

    NASA Astrophysics Data System (ADS)

    Malani, Ateeque; Amat, Miguel; Raghavanpillai, Anilkumar; Wysong, Ernest; Rutledge, Gregory

    2012-02-01

    Interfacial phenomena arise in a number of industrially important situations, such as repellency of liquids on surfaces, condensation, etc. In designing materials for such applications, the key component is their wetting behavior, which is characterized by three-phase static and dynamic contact angle phenomena. Molecular modeling has the potential to provide basic insight into the detailed picture of the three-phase contact line resolved on the sub-nanometer scale which is essential for the success of these materials. We have proposed a computational strategy to study three-phase contact phenomena, where buoyancy of a solid rod or particle is studied in a planar liquid film. The contact angle is readily evaluated by measuring the position of solid and liquid interfaces. As proof of concept, the methodology has been validated extensively using a simple Lennard-Jones (LJ) fluid in contact with an LJ surface. In the dynamic contact angle analysis, the evolution of contact angle as a function of force applied to the rod or particle is characterized by the pinning and slipping of the three phase contact line. Ultimately, complete wetting or de-wetting is observed, allowing molecular level characterization of the contact angle hysteresis.

  17. Investigation of the kinetics and microscopic mechanism of solid-solid phase transitions in HMX

    NASA Astrophysics Data System (ADS)

    Bowlan, Pamela; Suvorova, Natalya; Oschwald, Dave; Bowlan, John; Rector, Kirk; Henson, Bryan; Smilowitz, Laura

    2017-06-01

    Although studied intensely in the 2000's, a number of important questions about solid-solid phase transitions in the energetic organic material octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) remain. The mechanism by which one of the four isomorphs, known as δ, γ, α and β, transforms into another, and the conditions (i.e. temperature and pressure) and rates at which these transitions take place are still not fully known, yet important for predicting and controlling energy release phenomena in HMX such as detonation. The theory of virtual melting, by which a liquid forms at the interface of a nucleation site, is necessary to explain transformations between certain of the four different phases of HMX, such as the β to δ transition. However the existence of this disordered intermediate state has never been directly proven due to the need for both spatial (<µm), temporal (the lifetime of the transient melt state is unknown) and structural information. Also, while the β to δ transition was more thoroughly studied, less is known about the other 10 possible phase transitions. We will report on our study of phase transitions in HMX using X-ray diffraction and confocal Raman and near-field infrared microscopy.

  18. Controlling Fundamentals in High-Energy High-Rate Pulsed Power Materials Processing of Powdered Tungsten, Titanium Aluminides, and Copper-Graphite Composites

    DTIC Science & Technology

    1990-10-01

    phase systems such as tungsten; plastic flow of a minor low -temperature phase in a two phase non-interacting system such as tungsten- copper ; and...consolidation heat treatment. The de- the wetting of graphite by copper or during consolidation by this tech- tailed phase transformation evolution other...The driving potential for this solid state phase transformation is the free surface energy associated with the total powder particle surface area in the

  19. Proceedings of the 12th Army Symposium on Solid Mechanics, ’Synergism of Mechanics Mathematics and Materials’ 4-7 November 1991, Plymouth, Massachusetts.

    DTIC Science & Technology

    1991-11-07

    proposed that a phase transformation to untempered martensite (via austenite) occurred within the shear band [9]. Wittman et al used TEM observations to...porous materials is used to simulate the plate impact experiment. 1. Introduction While second phase precipitates or particles greatly enhance the...34Dispersed Particle Hard- ening of Aluminum- Copper Alloy Single Crystals", Acta Metall., Vol. 8, March, pp. 147-155. [2] Meiklejohn, W. H. and Skoda

  20. Nuclear fuel alloys or mixtures and method of making thereof

    DOEpatents

    Mariani, Robert Dominick; Porter, Douglas Lloyd

    2016-04-05

    Nuclear fuel alloys or mixtures and methods of making nuclear fuel mixtures are provided. Pseudo-binary actinide-M fuel mixtures form alloys and exhibit: body-centered cubic solid phases at low temperatures; high solidus temperatures; and/or minimal or no reaction or inter-diffusion with steel and other cladding materials. Methods described herein through metallurgical and thermodynamics advancements guide the selection of amounts of fuel mixture components by use of phase diagrams. Weight percentages for components of a metallic additive to an actinide fuel are selected in a solid phase region of an isothermal phase diagram taken at a temperature below an upper temperature limit for the resulting fuel mixture in reactor use. Fuel mixtures include uranium-molybdenum-tungsten, uranium-molybdenum-tantalum, molybdenum-titanium-zirconium, and uranium-molybdenum-titanium systems.

  1. Overview of NASA's Microgravity Materials Research Program

    NASA Technical Reports Server (NTRS)

    Downey, James Patton; Grugel, Richard

    2012-01-01

    The NASA microgravity materials program is dedicated to conducting microgravity experiments and related modeling efforts that will help us understand the processes associated with the formation of materials. This knowledge will help improve ground based industrial production of such materials. The currently funded investigations include research on the distribution of dopants and formation of defects in semiconductors, transitions between columnar and dendritic grain morphology, coarsening of phase boundaries, competition between thermally and kinetically favored phases, and the formation of glassy vs. crystalline material. NASA microgravity materials science investigators are selected for funding either through a proposal in response to a NASA Research Announcement or by participation in a team proposing to a foreign agency research announcement. In the latter case, a US investigator participating in a successful proposal to a foreign agency can then apply to NASA for funding of an unsolicited proposal. The program relies on cooperation with other aerospace partners from around the world. The ISS facilities used for these investigations are provided primarily by partnering with foreign agencies and in most cases the US investigators are working as a part of a larger team studying a specific area of materials science. The following facilities are to be utilized for the initial investigations. The ESA provided Low Gradient Facility and the Solidification and Quench Inserts to the Materials Research Rack/Materials Science Laboratory are to be used primarily for creating bulk samples that are directionally solidified or quenched from a high temperature melt. The CNES provided DECLIC facility is used to observe morphological development in transparent materials. The ESA provided Electro-Magnetic Levitator (EML) is designed to levitate, melt and then cool samples in order to study nucleation behavior. The facility provides conditions in which nucleation of the solid is not triggered from the wall and in which fluid flows in the sample can be controlled and manipulated. These conditions allow scientists ideal conditions for understanding the relative amounts and distribution of different phases that form in the solid. Finally, the Coarsening of Solid Liquid Melts hardware allows quenching of low temperature samples in the Microgravity Science Glovebox.

  2. Biorefinery process for production of paper and oligomers from Leucaena leucocephala K360 with or without prior autohydrolysis.

    PubMed

    Feria, M J; García, J C; Díaz, M J; Fernández, M; López, F

    2012-12-01

    Lignocellulosic material from Leucaena leucocephala was subjected to a two-stage fractionation process to obtain a valorized effluent containing hemicellulose derivatives and a solid phase for producing cellulose pulp by conventional soda-anthraquinone delignification. This solid phase allows the production of cellulose pulp, under less rigorous conditions from NaOH-AQ process (177 °C, 21%, 120 min) than without pretreatment delignification (185 °C, 25%, 150 min) and better or similar properties in the paper sheets obtained (yield 27.6 and 34.0%, brightness 39.3 and 31.6% ISO, tensile index 7.8 and 10.5 N m/g, burst index 0.43 and 0.29 MPa m(2)/kg with and without previous autohydrolysis) have be found. Also, the first autohydrolysis stage allows up to 46.6% of the initial hemicellulose in the raw material to be extracted as xylooligomers, xylose and furfural into the liquid phase. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Electrolysis-induced protonation of VO2 thin film transistor for the metal-insulator phase modulation

    NASA Astrophysics Data System (ADS)

    Katase, Takayoshi; Endo, Kenji; Ohta, Hiromichi

    2016-02-01

    Compared to state-of-the-art modulation techniques, protonation is the most ideal to control the electrical and optical properties of transition metal oxides (TMOs) due to its intrinsic non-volatile operation. However, the protonation of TMOs is not typically utilized for solid-state devices because of imperative high-temperature annealing treatment in hydrogen source. Although one solution for room temperature (RT) protonation of TMOs is liquid-phase electrochemistry, it is unsuited for practical purposes due to liquid-leakage problem. Herein we demonstrate solid-state RT-protonation of vanadium dioxide (VO2), which is a well-known thermochromic TMO. We fabricated the three terminal thin-film-transistor structure on an insulating VO2 film using a water-infiltrated nanoporous glass, which serves as a solid electrolyte. For gate voltage application, water electrolysis and protonation/deprotonation of VO2 film surface occurred, leading to reversible metal-insulator phase conversion of ~11-nm-thick VO2 layer. The protonation was clearly accompanied by the structural change from an insulating monoclinic to a metallic tetragonal phase. Present results offer a new route for the development of electro-optically active solid-state devices with TMO materials by engineering RT protonation.

  4. Room-temperature ferromagnetism in Fe-based perovskite solid solution in lead-free ferroelectric Bi0.5Na0.5TiO3 materials

    NASA Astrophysics Data System (ADS)

    Hung, Nguyen The; Bac, Luong Huu; Trung, Nguyen Ngoc; Hoang, Nguyen The; Van Vinh, Pham; Dung, Dang Duc

    2018-04-01

    The integration of ferromagnetism in lead-free ferroelectric materials is important to fabricate smart materials for electronic devices. In this work, (1 - x)Bi0.5Na0.5TiO3 + xMgFeO3-δ materials (x = 0-9 mol%) were prepared through sol-gel method. X-ray diffraction characterization indicated that MgFeO3-δ materials existed as a well solid solution in lead-free ferroelectric Bi0.5Na0.5TiO3 materials. The rhombohedral structure of Bi0.5Na0.5TiO3 materials was distorted due to the random distribution of Mg and Fe cations into the host lattice. The reduced optical band gap and the induced room-temperature ferromagnetism were due to the spin splitting of transition metal substitution at the B-site of perovskite Bi0.5Na0.5TiO3 and the modification by A-site co-substitution. This work elucidates the role of secondary phase as solid solution in Bi0.5Na0.5TiO3 material for development of lead-free multiferroelectric materials.

  5. Numerical Analysis of a Class of THM Coupled Model for Porous Materials

    NASA Astrophysics Data System (ADS)

    Liu, Tangwei; Zhou, Jingying; Lu, Hongzhi

    2018-01-01

    We consider the coupled models of the Thermo-hydro-mechanical (THM) problem for porous materials which arises in many engineering applications. Firstly, mathematical models of the THM coupled problem for porous materials were discussed. Secondly, for different cases, some numerical difference schemes of coupled model were constructed, respectively. Finally, aassuming that the original water vapour effect is neglectable and that the volume fraction of liquid phase and the solid phase are constants, the nonlinear equations can be reduced to linear equations. The discrete equations corresponding to the linear equations were solved by the Arnodli method.

  6. Studies in Three Phase Gas-Liquid Fluidised Systems

    NASA Astrophysics Data System (ADS)

    Awofisayo, Joyce Ololade

    1992-01-01

    Available from UMI in association with The British Library. The work is a logical continuation of research started at Aston some years ago when studies were conducted on fermentations in bubble columns. The present work highlights typical design and operating problems that could arise in such systems as waste water, chemical, biochemical and petroleum operations involving three-phase, gas-liquid -solid fluidisation; such systems are in increasing use. It is believed that this is one of few studies concerned with "true" three-phase, gas-liquid-solid fluidised systems, and that this work will contribute significantly to closing some of the gaps in knowledge in this area. The research work was experimentally based and involved studies of the hydrodynamic parameters, phase holdups (gas and solid), particle mixing and segregation, and phase flow dynamics (flow regime and circulation patterns). The studies have focused particularly on the solid behaviour and the influence of properties of solids present on the above parameters in three-phase, gas-liquid-solid fluidised systems containing single particle components and those containing binary and ternary mixtures of particles. All particles were near spherical in shape and two particle sizes and total concentration levels were used. Experiments were carried out in two- and three-dimensional bubble columns. Quantitative results are presented in graphical form and are supported by qualitative results from visual studies which are also shown as schematic diagrams and in photographic form. Gas and solid holdup results are compared for air-water containing single, binary and ternary component particle mixtures. It should be noted that the criteria for selection of the materials used are very important if true three-phase fluidisation is to be achieved: this is very evident when comparing the results with those in the literature. The fluid flow and circulation patterns observed were assessed for validation of the generally accepted patterns, and the author believes that the present work provides more accurate insight into the modelling of liquid circulation in bubble columns. The characteristic bubbly flow at low gas velocity in a two-phase system is suppressed in the three-phase system. The degree of mixing within the system is found to be dependent on flow regime, liquid circulation and the ratio of solid phase physical properties.

  7. Amorphous and nanocrystalline luminescent Si and Ge obtained via a solid-state chemical metathesis synthesis route

    NASA Astrophysics Data System (ADS)

    McMillan, Paul F.; Gryko, Jan; Bull, Craig; Arledge, Richard; Kenyon, Anthony J.; Cressey, Barbara A.

    2005-03-01

    A new solid-state metathesis synthesis route was applied to obtain bulk samples of amorphous or microcrystalline Si and Ge. The method involves reaction of Zintl phases such as NaSi or NaGe, with ammonium or metal (e.g., CuCl, CoBr 2) halides. The driving force for the solid-state reaction is provided by the formation of alkali halides and the transition metals or metal silicides, or gaseous ammonia and hydrogen. The semiconductors were purified by washing to remove other solid products. The amorphous semiconductors were obtained in bulk form from reactions carried out at 200-300 °C. Syntheses at higher temperatures gave rise to microcrystalline semiconductors, or to micro-/nanocrystalline particles contained within the amorphous material. Similar crystalline/amorphous composites were obtained after heat treatment of bulk amorphous materials.

  8. Enhanced ionic conductivity with Li{sub 7}O{sub 2}Br{sub 3} phase in Li{sub 3}OBr anti-perovskite solid electrolyte

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhu, Jinlong, E-mail: jlzhu04@physics.unlv.edu, E-mail: yusheng.zhao@unlv.edu, E-mail: zhaoys@sustc.edu.cn; Li, Shuai; Zhang, Yi

    Cubic anti-perovskites with general formula Li{sub 3}OX (X = Cl, Br, I) were recently reported as superionic conductors with the potential for use as solid electrolytes in all-solid-state lithium ion batteries. These electrolytes are nonflammable, low-cost, and suitable for thermoplastic processing. However, the primary obstacle of its practical implementation is the relatively low ionic conductivity at room temperature. In this work, we synthesized a composite material consisting of two anti-perovskite phases, namely, cubic Li{sub 3}OBr and layered Li{sub 7}O{sub 2}Br{sub 3,} by solid state reaction routes. The results indicate that with the phase fraction of Li{sub 7}O{sub 2}Br{sub 3} increasing to 44 wt.more » %, the ionic conductivity increased by more than one order of magnitude compared with pure phase Li{sub 3}OBr. Formation energy calculations revealed the meta-stable nature of Li{sub 7}O{sub 2}Br{sub 3}, which supports the great difficulty in producing phase-pure Li{sub 7}O{sub 2}Br{sub 3} at ambient pressure. Methods of obtaining phase-pure Li{sub 7}O{sub 2}Br{sub 3} will continue to be explored, including both high pressure and metathesis techniques.« less

  9. Multistep synthesis on SU-8: combining microfabrication and solid-phase chemistry on a single material.

    PubMed

    Cavalli, Gabriel; Banu, Shahanara; Ranasinghe, Rohan T; Broder, Graham R; Martins, Hugo F P; Neylon, Cameron; Morgan, Hywel; Bradley, Mark; Roach, Peter L

    2007-01-01

    SU-8 is an epoxy-novolac resin and a well-established negative photoresist for microfabrication and microengineering. The photopolymerized resist is an extremely highly crosslinked polymer showing outstanding chemical and physical robustness with residual surface epoxy groups amenable for chemical functionalization. In this paper we describe, for the first time, the preparation and surface modification of SU-8 particles shaped as microbars, the attachment of appropriate linkers, and the successful application of these particles to multistep solid-phase synthesis leading to oligonucleotides and peptides attached in an unambiguous manner to the support surface.

  10. Phase Behavior of Complex Superprotonic Solid Acids

    NASA Astrophysics Data System (ADS)

    Panithipongwut, Chatr

    Superprotonic phase transitions and thermal behaviors of three complex solid acid systems are presented, namely Rb3H(SO4) 2-RbHSO4 system, Rb3H(SeO4)2-Cs 3H(SeO4)2 solid solution system, and Cs6 (H2SO4)3(H1.5PO4) 4. These material systems present a rich set of phase transition characteristics that set them apart from other, simpler solid acids. A.C. impedance spectroscopy, high-temperature X-ray powder diffraction, and thermal analysis, as well as other characterization techniques, were employed to investigate the phase behavior of these systems. Rb3H(SO4)2 is an atypical member of the M3H(XO4)2 class of compounds (M = alkali metal or NH4+ and X = S or Se) in that a transition to a high-conductivity state involves disproportionation into two phases rather than a simple polymorphic transition [1]. In the present work, investigations of the Rb3H(SO4)2-RbHSO4 system have revealed the disproportionation products to be Rb2SO 4 and the previously unknown compound Rb5H3(SO 4)4. The new compound becomes stable at a temperature between 25 and 140 °C and is isostructural to a recently reported trigonal phase with space group P3m of Cs5H 3(SO4)4 [2]. At 185 °C the compound undergoes an apparently polymorphic transformation with a heat of transition of 23.8 kJ/mol and a slight additional increase in conductivity. The compounds Rb3H(SeO4)2 and Cs 3H(SeO4)2, though not isomorphous at ambient temperatures, are quintessential examples of superprotonic materials. Both adopt monoclinic structures at ambient temperatures and ultimately transform to a trigonal (R3m) superprotonic structure at slightly elevated temperatures, 178 and 183 °C, respectively. The compounds are completely miscible above the superprotonic transition and show extensive solubility below it. Beyond a careful determination of the phase boundaries, we find a remarkable 40-fold increase in the superprotonic conductivity in intermediate compositions rich in Rb as compared to either end-member. The compound Cs6(H2SO4)3(H 1.5PO4)4 is unusual amongst solid acid compounds in that it has a complex cubic structure at ambient temperature and apparently transforms to a simpler cubic structure of the CsCl-type (isostructural with CsH2PO4) at its transition temperature of 100-120 °C [3]. Here it is found that, depending on the level of humidification, the superprotonic transition of this material is superimposed with a decomposition reaction, which involves both exsolution of (liquid) acid and loss of H2O. This reaction can be suppressed by application of sufficiently high humidity, in which case Cs6(H2SO4)3(H 1.5PO4)4 undergoes a true superprotonic transition. It is proposed that, under conditions of low humidity, the decomposition/dehydration reaction transforms the compound to Cs6(H2-0.5xSO 4)3(H1.5PO4)4-x, also of the CsCl structure type at the temperatures of interest, but with a smaller unit cell. With increasing temperature, the decomposition/dehydration proceeds to greater and greater extent and unit cell of the solid phase decreases. This is identified to be the source of the apparent negative thermal expansion behavior. References: [1] L.A. Cowan, R.M. Morcos, N. Hatada, A. Navrotsky, S.M. Haile, Solid State Ionics 179 (2008) (9-10) 305. [2] M. Sakashita, H. Fujihisa, K.I. Suzuki, S. Hayashi, K. Honda, Solid State Ionics 178 (2007) (21-22) 1262. [3] C.R.I. Chisholm, Superprotonic Phase Transitions in Solid Acids: Parameters affecting the presence and stability of superprotonic transitions in the MHnXO4 family of compounds (X=S, Se, P, As; M=Li, Na, K, NH4, Rb, Cs), Materials Science, California Institute of Technology, Pasadena, California (2003).

  11. Effect of various electrokinetic treatment regimes on solids surface properties and thermal behavior of oil sediments.

    PubMed

    Kariminezhad, Esmaeel; Elektorowicz, Maria

    2018-04-10

    The electrokinetic process has shown its ability to separate the different material phases. However, not much is known about the effect of the electric fields on the surface properties of solids in the oil sediments and their behavior under different electrical regimes. In this study, the effect of four different types of electrical current on the surface properties of oil sediments was investigated, namely constant direct current (CDC), pulsed direct current (PDC), incremental direct current (IDC) and decremental direct current (DDC). X-ray photoelectron spectroscopy (XPS) analyses showed a decrease in the concentration of carbon from 99% in centrifuged samples to 63% on the surface of the solids in the PDC-treated oil sediment. Wettability alteration and contact angle studies showed an enhance in hydrophilicity of the solids following electrokinetic treatment. A significant change in carbon and oxygen-containing functionalities at the surface solids of the DDC-treated sediment was also observed. Thermogravimetric analyses (TGA) confirmed the ability of electrokinetic treatment in separating the phases by shifting the thermogram profiles towards lower temperatures. The findings showed that the electrokinetic process exerts its effect by altering the surface properties of the sediment solids and destabilizing water-in-oil emulsions to facilitate phase separation of this complex waste. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Soil

    USDA-ARS?s Scientific Manuscript database

    Soil is a diverse natural material characterized by solid, liquid, and gas phases that impart unique chemical, physical, and biological properties. Soil provides many key functions, including supporting plant growth and providing environmental remediation. Monitoring key soil properties and processe...

  13. Effects of Shock-Breakout Pressure on Ejection of Micron-Scale Material from Shocked Tin Surfaces

    NASA Astrophysics Data System (ADS)

    Zellner, Michael; Hammerberg, James; Hixson, Robert; Morley, Kevin; Obst, Andrew; Olson, Russell; Payton, Jeremy; Rigg, Paulo; Buttler, William; Grover, Michael; Iverson, Adam; Macrum, Gregory; Stevens, Gerald; Turley, William; Veeser, Lynn; Routley, Nathan

    2007-06-01

    Los Alamos National Lab (LANL) is actively engaged in the development of a model to predict the formation of micron-scale fragments ejected (ejecta) from shocked metal surfaces. The LANL ejecta model considers that the amount of ejecta is mainly related to the material's phase on shock release at the free-surface. This effort investigates the relation between ejecta production and shock-breakout pressure for Sn shocked with high explosives to pressures near the solid-on-release/partial-liquid-on-release phase transition region. We found that the amount of ejecta produced for shock-breakout pressures that resulted in partial-liquid-on-release increased significantly compared to that which resulted in solid-on-release. Additionally, we found that the amount of ejecta remained relatively constant within the partial-liquid-on-release, regardless of shock-breakout pressure.

  14. Pressure Effects on the Ejection of Material from Shocked Tin Surfaces

    NASA Astrophysics Data System (ADS)

    Zellner, M. B.; Grover, M.; Hammerberg, J. E.; Hixson, R. S.; Iverson, A. J.; Macrum, G. S.; Morley, K. B.; Obst, A. W.; Olson, R. T.; Payton, J. R.; Rigg, P. A.; Routley, N.; Stevens, G. D.; Turley, W. D.; Veeser, L.; Buttler, W. T.

    2007-12-01

    Los Alamos National Lab (LANL) is actively engaged in the development of a model to predict the formation of micron-scale fragments ejected (ejecta) from shocked metals that have surface defects. The LANL ejecta model considers that the amount of ejecta is mainly related to the material's phase on shock release at the free-surface. This effort investigates the relation between ejecta production and shock-breakout pressure for Sn shocked with high explosives to pressures near the solid-on-release/partial-liquid-on-release phase transition region. We found that the amount of ejecta produced for shock-breakout pressures that resulted in partial-liquid-on-release increased significantly compared to that which resulted in solid-on-release. Additionally, we found that the amount of ejecta remained relatively constant within the partial-liquid-on-release, regardless of shock-breakout pressure.

  15. Numerical analysis of fluid flow and heat transfer during melting inside a cylindrical container for thermal energy storage system

    NASA Astrophysics Data System (ADS)

    Bellan, Selvan; Cheok, Cho Hyun; Gokon, Nobuyuki; Matsubara, Koji; Kodama, Tatsuya

    2017-06-01

    This paper presents a numerical analysis of unconstrained melting of high temperature(>1000K) phase change material (PCM) inside a cylindrical container. Sodium chloride and Silicon carbide have been used as phase change material and shell of the capsule respectively. The control volume discretization approach has been used to solve the conservation equations of mass, momentum and energy. The enthalpy-porosity method has been used to track the solid-liquid interface of the PCM during melting process. Transient numerical simulations have been performed in order to study the influence of radius of the capsule and the Stefan number on the heat transfer rate. The simulation results show that the counter-clockwise Buoyancy driven convection over the top part of the solid PCM enhances the melting rate quite faster than the bottom part.

  16. Ionic Liquid-Hybrid Molecularly Imprinted Material-Filter Solid-Phase Extraction Coupled with HPLC for Determination of 6-Benzyladenine and 4-Chlorophenoxyacetic Acid in Bean Sprouts.

    PubMed

    Han, Yehong; Yang, Chunliu; Zhou, Yang; Han, Dandan; Yan, Hongyuan

    2017-03-01

    A new method involving ionic liquid-hybrid molecularly imprinted material-filter solid-phase extraction coupled to high-performance liquid chromatography (IL-HIM-FSPE-HPLC) was developed for the simultaneous isolation and determination of 6-benzyladenine (6-BA) and 4-chlorophenoxyacetic acid (4-CPA) in bean sprouts. Sample preconcentration was performed using a modified filter, with the new IL-HIM as the adsorbent, which shows double adsorption. The first adsorption involves special recognition of molecular imprinting, and the second involves ion exchange and electrostatic attraction caused by the ionic liquid. This method combines the advantages of ionic liquids, hybrid materials, and molecularly imprinted polymers and was successfully applied to determine 6-BA and 4-CPA in bean sprouts. The adsorption of 6-BA to IL-HIM is based on selective imprinted recognition, whereas the adsorption of 4-CPA is mainly dependent on ion-exchange interactions.

  17. [The progress in speciation analysis of trace elements by atomic spectrometry].

    PubMed

    Wang, Zeng-Huan; Wang, Xu-Nuo; Ke, Chang-Liang; Lin, Qin

    2013-12-01

    The main purpose of the present work is to review the different non-chromatographic methods for the speciation analysis of trace elements in geological, environmental, biological and medical areas. In this paper, the sample processing methods in speciation analysis were summarized, and the main strategies for non-chromatographic technique were evaluated. The basic principles of the liquid extractions proposed in the published literatures recently and their advantages and disadvantages were discussed, such as conventional solvent extraction, cloud point extraction, single droplet microextraction, and dispersive liquid-liquid microextraction. Solid phase extraction, as a non-chromatographic technique for speciation analysis, can be used in batch or in flow detection, and especially suitable for the online connection to atomic spectrometric detector. The developments and applications of sorbent materials filled in the columns of solid phase extraction were reviewed. The sorbents include chelating resins, nanometer materials, molecular and ion imprinted materials, and bio-sorbents. Other techniques, e. g. hydride generation technique and coprecipitation, were also reviewed together with their main applications.

  18. Radioactivity concentration in liquid and solid phases of scale and sludge generated in the petroleum industry.

    PubMed

    Paranhos Gazineu, Maria Helena; de Araújo, Andressa Arruda; Brandão, Yana Batista; Hazin, Clovis Abrahão; de O Godoy, José Marcos

    2005-01-01

    Scales and sludge generated during oil extraction and production can contain uranium, thorium, radium and other natural radionuclides, which can cause exposure of maintenance personnel. This work shows how the oil content can influence the results of measurements of radionuclide concentration in scale and sludge. Samples were taken from a PETROBRAS unit in Northeast Brazil. They were collected directly from the inner surface of water pipes or from barrels stored in the waste storage area of the E&P unit. The oil was separated from the solids with a Soxhlet extractor by using aguarras at 90+/-5 degrees C as solvent. Concentrations of 226Ra and 228Ra in the samples were determined before and after oil extraction by using an HPGe gamma spectrometric system. The results showed an increase in the radionuclide concentration in the solid (dry) phase, indicating that the above radionuclides concentrate mostly in the solid material.

  19. Composite materials for thermal energy storage

    DOEpatents

    Benson, David K.; Burrows, Richard W.; Shinton, Yvonne D.

    1986-01-01

    The present invention discloses composite material for thermal energy storage based upon polyhydric alcohols, such as pentaerythritol, trimethylol ethane (also known as pentaglycerine), neopentyl glycol and related compounds including trimethylol propane, monoaminopentaerythritol, diamino-pentaerythritol and tris(hydroxymethyl)acetic acid, separately or in combinations, which provide reversible heat storage through crystalline phase transformations. These phase change materials do not become liquid during use and are in contact with at least one material selected from the group consisting of metals, carbon siliceous, plastic, cellulosic, natural fiber, artificial fiber, concrete, gypsum, porous rock, and mixtures thereof. Particulate additions, such as aluminum or graphite powders, as well as metal and carbon fibers can also be incorporated therein. Particulate and/or fibrous additions can be introduced into molten phase change materials which can then be cast into various shapes. After the phase change materials have solidified, the additions will remain dispersed throughout the matrix of the cast solid. The polyol is in contact with at least one material selected from the group consisting of metals, carbon siliceous, plastic, cellulosic, natural fiber, artificial fiber, concrete, gypsum, and mixtures thereof.

  20. Silicon nanowire synthesis by a vapor-liquid-solid approach.

    PubMed

    Mao, Aaron; Ng, H T; Nguyen, Pho; McNeil, Melanie; Meyyappan, M

    2005-05-01

    Synthesis of silicon nanowires is studied by using a vapor-liquid-solid growth technique. Silicon tetrachloride reduction with hydrogen in the gas phase is used with gold serving as catalyst to facilitate growth. Only a narrow set of conditions of SiCl4 concentration and temperature yield straight nanowires. High concentrations and temperatures generally result in particulates, catalyst coverage and deactivation, and coatinglike materials.

  1. Silicon nanowire synthesis by a vapor-liquid-solid approach

    NASA Technical Reports Server (NTRS)

    Mao, Aaron; Ng, H. T.; Nguyen, Pho; McNeil, Melanie; Meyyappan, M.

    2005-01-01

    Synthesis of silicon nanowires is studied by using a vapor-liquid-solid growth technique. Silicon tetrachloride reduction with hydrogen in the gas phase is used with gold serving as catalyst to facilitate growth. Only a narrow set of conditions of SiCl4 concentration and temperature yield straight nanowires. High concentrations and temperatures generally result in particulates, catalyst coverage and deactivation, and coatinglike materials.

  2. IN SITU SOURCE TREATMENT OF CR(VI) USING A FE(II)-BASED REDUCTANT BLEND: LONG-TERM MONITORING AND EVALUATION

    EPA Science Inventory

    The long-term effectiveness of a FeSO4 + Na2S2O4 reductant solution blend for in situ saturated zone treatment of dissolved and solid phase Cr(VI) in a high pH chromite ore processing solid waste (COPSW) fill material was investigated. Two field pilot injection studies were cond...

  3. (Magneto)caloric refrigeration: Is there light at the end of the tunnel?

    DOE PAGES

    Pecharsky, Vitalij K.; Cui, Jun; Johnson, Duane D.

    2016-07-11

    Here, caloric cooling and heat pumping rely on reversible thermal effects triggered in solids by magnetic, electric or stress fields. In the recent past, there have been several successful demonstrations of using first-order phase transition materials in laboratory cooling devices based on both the giant magnetocaloric and elastocaloric effects. All such materials exhibit non-equilibrium behaviours when driven through phase transformations by corresponding fields. Common wisdom is that non-equilibrium states should be avoided; yet, as we show using a model material exhibiting a giant magnetocaloric effect, non-equilibrium phase-separated states offer a unique opportunity to achieve uncommonly large caloric effects by verymore » small perturbations of the driving field(s).« less

  4. (Magneto)caloric refrigeration: Is there light at the end of the tunnel?

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pecharsky, Vitalij K.; Cui, Jun; Johnson, Duane D.

    Here, caloric cooling and heat pumping rely on reversible thermal effects triggered in solids by magnetic, electric or stress fields. In the recent past, there have been several successful demonstrations of using first-order phase transition materials in laboratory cooling devices based on both the giant magnetocaloric and elastocaloric effects. All such materials exhibit non-equilibrium behaviours when driven through phase transformations by corresponding fields. Common wisdom is that non-equilibrium states should be avoided; yet, as we show using a model material exhibiting a giant magnetocaloric effect, non-equilibrium phase-separated states offer a unique opportunity to achieve uncommonly large caloric effects by verymore » small perturbations of the driving field(s).« less

  5. Application of binomial-edited CPMG to shale characterization

    USGS Publications Warehouse

    Washburn, Kathryn E.; Birdwell, Justin E.

    2014-01-01

    Unconventional shale resources may contain a significant amount of hydrogen in organic solids such as kerogen, but it is not possible to directly detect these solids with many NMR systems. Binomial-edited pulse sequences capitalize on magnetization transfer between solids, semi-solids, and liquids to provide an indirect method of detecting solid organic materials in shales. When the organic solids can be directly measured, binomial-editing helps distinguish between different phases. We applied a binomial-edited CPMG pulse sequence to a range of natural and experimentally-altered shale samples. The most substantial signal loss is seen in shales rich in organic solids while fluids associated with inorganic pores seem essentially unaffected. This suggests that binomial-editing is a potential method for determining fluid locations, solid organic content, and kerogen–bitumen discrimination.

  6. Thermodynamic phase behavior of API/polymer solid dispersions.

    PubMed

    Prudic, Anke; Ji, Yuanhui; Sadowski, Gabriele

    2014-07-07

    To improve the bioavailability of poorly soluble active pharmaceutical ingredients (APIs), these materials are often integrated into a polymer matrix that acts as a carrier. The resulting mixture is called a solid dispersion. In this work, the phase behaviors of solid dispersions were investigated as a function of the API as well as of the type and molecular weight of the carrier polymer. Specifically, the solubility of artemisinin and indomethacin was measured in different poly(ethylene glycol)s (PEG 400, PEG 6000, and PEG 35000). The measured solubility data and the solubility of sulfonamides in poly(vinylpyrrolidone) (PVP) K10 and PEG 35000 were modeled using the perturbed-chain statistical associating fluid theory (PC-SAFT). The results show that PC-SAFT predictions are in a good accordance with the experimental data, and PC-SAFT can be used to predict the whole phase diagram of an API/polymer solid dispersion as a function of the kind of API and polymer and of the polymer's molecular weight. This remarkably simplifies the screening process for suitable API/polymer combinations.

  7. Phonon scattering mechanisms dictating the thermal conductivity of lead zirconate titanate (PbZr 1- xTi xO 3) thin films across the compositional phase diagram

    DOE PAGES

    Foley, Brian M.; Paisley, Elizabeth A.; DiAntonio, Christopher; ...

    2017-05-23

    This paper represents a thorough investigation of the thermal conductivity (κ) in both thin film and bulk PbZr 1–xTi xO 3 (PZT) across the compositional phase diagram. Given the technological importance of PZT as a superb piezoelectric and ferroelectric material in devices and systems impacting a wide array of industries, this research serves to fill the gap in knowledge regarding the thermal properties. The thermal conductivities of both thin film and bulk PZT are found to vary by a considerable margin as a function of composition x. Additionally, we observe a discontinuity in κ in the vicinity of the morphotropicmore » phase boundary (MPB, x = 0.48) where there is a 20%–25% decrease in κ in our thin film data, similar to that found in literature data for bulk PZT. The comparison between bulk and thin film materials highlights the sensitivity of κ to size effects such as film thickness and grain size even in disordered alloy/solid-solution materials. A model for the thermal conductivity of PZT as a function of composition (κ(x)) is presented, which enables the application of the virtual crystal approximation for alloy-type material systems with very different crystals structures, resulting in differing temperature trends for κ. We show that in the case of crystalline solid-solutions where the thermal conductivity of one of the parent materials exhibits glass-like temperature trends the compositional dependence of thermal conductivity is relatively constant for most values of x. Finally, this is in stark contrast with the typical trends of thermal conductivity with x in alloys, where the thermal conductivity increases dramatically as the composition of the alloy or solid-solution approaches that of a pure parent materials (i.e., as x = 0 or 1).« less

  8. Phonon scattering mechanisms dictating the thermal conductivity of lead zirconate titanate (PbZr 1- xTi xO 3) thin films across the compositional phase diagram

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Foley, Brian M.; Paisley, Elizabeth A.; DiAntonio, Christopher

    This paper represents a thorough investigation of the thermal conductivity (κ) in both thin film and bulk PbZr 1–xTi xO 3 (PZT) across the compositional phase diagram. Given the technological importance of PZT as a superb piezoelectric and ferroelectric material in devices and systems impacting a wide array of industries, this research serves to fill the gap in knowledge regarding the thermal properties. The thermal conductivities of both thin film and bulk PZT are found to vary by a considerable margin as a function of composition x. Additionally, we observe a discontinuity in κ in the vicinity of the morphotropicmore » phase boundary (MPB, x = 0.48) where there is a 20%–25% decrease in κ in our thin film data, similar to that found in literature data for bulk PZT. The comparison between bulk and thin film materials highlights the sensitivity of κ to size effects such as film thickness and grain size even in disordered alloy/solid-solution materials. A model for the thermal conductivity of PZT as a function of composition (κ(x)) is presented, which enables the application of the virtual crystal approximation for alloy-type material systems with very different crystals structures, resulting in differing temperature trends for κ. We show that in the case of crystalline solid-solutions where the thermal conductivity of one of the parent materials exhibits glass-like temperature trends the compositional dependence of thermal conductivity is relatively constant for most values of x. Finally, this is in stark contrast with the typical trends of thermal conductivity with x in alloys, where the thermal conductivity increases dramatically as the composition of the alloy or solid-solution approaches that of a pure parent materials (i.e., as x = 0 or 1).« less

  9. Phase separation in biopolymer gels: a low- to high-solid exploration of structural morphology and functionality.

    PubMed

    Kasapis, Stefan

    2008-04-01

    Phase separation in protein and polysaccharide gels remains one of the basic tools of achieving the required structural properties and textural profile in food product formulations. As ever, the industrialist is faced with the challenge of innovation in an increasingly competitive market in terms of ingredient cost, product added-value, and expectations of a healthy life-style to mention but a few. It appears, however, that a gap persists between the fundamental knowledge and a direct application to food related concepts with a growing need for scientific input. Furthermore, within the context of materials science, there is a tendency to examine research findings in either low- or high-solid systems without considering synergistic insights/benefits to contemporary needs, spanning the full range of relevant time-, length-, and concentration scales. This review highlights the latest attempts made to utilize and further develop fundamental protocols from the advanced synthetic polymer research as a source of inspiration for contemporary bio-related applications in low- and intermediate-solid composite gels. Then, it takes advantage of this school of thought to "force a passage" through the phase topology and molecular dynamics of binary biopolymer mixtures at high levels of co-solute. It is hoped that these phenomenological and fundamental tools should be able to bridge the divide in the analysis of the two "types" of composite materials (from low to high solids) thus dealing effectively with the specific and often intricate problems of their science and applications.

  10. Application of the powder of porous titanium carbide ceramics to a reusable adsorbent for environmental pollutants.

    PubMed

    Moriwaki, Hiroshi; Kitajima, Shiori; Shirai, Koji; Kiguchi, Kenji; Yamada, Osamu

    2011-01-30

    The aim of this study is to investigate the utilization of the powder of porous titanium carbide (TiC) ceramics as a novel adsorbent or a material for solid-phase extraction (SPE). The adsorption and elution of inorganic and organic pollutants, Pb(II), 2,4,6-trichlorophenol (TCP), perfluorooctane sulfonate (PFOS), and perfluorooctanoic acid (PFOA), to the material were evaluated. The cartridge packed with TiC ceramics powder was used for the extraction test of pollutants. The solution containing pollutants at 1.0 μg mL(-1) was passed through the TiC cartridge, and the substances were almost quantitatively removed. Furthermore, the pollutants retained in the cartridge were eluted with 3N HCl for Pb(II) and with methanol for organic pollutants. The recoveries of pollutants were over 80%. In addition, we used the TiC cartridge for the solid-phase extraction of water samples (500 mL each of the distilled water and the river water) by adding pollutants at determined concentrations. Every pollutant was adsorbed almost quantitatively, and eluted by 3N HCl or methanol. From these results, we concluded that the powder of porous TiC ceramics is a useful reusable adsorbent for the water cleanup and solid-phase extraction. Copyright © 2010 Elsevier B.V. All rights reserved.

  11. Biomimetic Silica Nanoparticles Prepared by a Combination of Solid-Phase Imprinting and Ostwald Ripening.

    PubMed

    Piletska, Elena; Yawer, Heersh; Canfarotta, Francesco; Moczko, Ewa; Smolinska-Kempisty, Katarzyna; Piletsky, Stanislav S; Guerreiro, Antonio; Whitcombe, Michael J; Piletsky, Sergey A

    2017-09-14

    Herein we describe the preparation of molecularly imprinted silica nanoparticles by Ostwald ripening in the presence of molecular templates immobilised on glass beads (the solid-phase). To achieve this, a seed material (12 nm diameter silica nanoparticles) was incubated in phosphate buffer in the presence of the solid-phase. Phosphate ions act as a catalyst in the ripening process which is driven by differences in surface energy between particles of different size, leading to the preferential growth of larger particles. Material deposited in the vicinity of template molecules results in the formation of sol-gel molecular imprints after around 2 hours. Selective washing and elution allows the higher affinity nanoparticles to be isolated. Unlike other strategies commonly used to prepare imprinted silica nanoparticles this approach is extremely simple in nature and can be performed under physiological conditions, making it suitable for imprinting whole proteins and other biomacromolecules in their native conformations. We have demonstrated the generic nature of this method by preparing imprinted silica nanoparticles against targets of varying molecular mass (melamine, vancomycin and trypsin). Binding to the imprinted particles was demonstrated in an immunoassay (ELISA) format in buffer and complex media (milk or blood plasma) with sub-nM detection ability.

  12. A mixed-penalty biphasic finite element formulation incorporating viscous fluids and material interfaces.

    PubMed

    Chan, B; Donzelli, P S; Spilker, R L

    2000-06-01

    The fluid viscosity term of the fluid phase constitutive equation and the interface boundary conditions between biphasic, solid and fluid domains have been incorporated into a mixed-penalty finite element formulation of the linear biphasic theory for hydrated soft tissue. The finite element code can now model a single-phase viscous incompressible fluid, or a single-phase elastic solid, as limiting cases of a biphasic material. Interface boundary conditions allow the solution of problems involving combinations of biphasic, fluid and solid regions. To incorporate these conditions, the volume-weighted mixture velocity is introduced as a degree of freedom at interface nodes so that the kinematic continuity conditions are satisfied by conventional finite element assembly techniques. Results comparing our numerical method with an independent, analytic solution for the problem of Couette flow over rigid and deformable porous biphasic layers show that the finite element code accurately predicts the viscous fluid flows and deformation in the porous biphasic region. Thus, the analysis can be used to model the interface between synovial fluid and articular cartilage in diarthrodial joints. This is an important step toward modeling and understanding the mechanisms of joint lubrication and another step toward fully modeling the in vivo behavior of a diarthrodial joint.

  13. Bacterial toxicity assessment of drinking water treatment residue (DWTR) and lake sediment amended with DWTR.

    PubMed

    Yuan, Nannan; Wang, Changhui; Pei, Yuansheng

    2016-11-01

    Drinking water treatment residue (DWTR) seems to be very promising for controlling lake sediment pollution. Logically, acquisition of the potential toxicity of DWTR will be beneficial for its applications. In this study, the toxicity of DWTR and sediments amended with DWTR to Aliivibrio fischeri was evaluated based on the Microtox(®) solid and leachate phase assays, in combination with flow cytometry analyses and the kinetic luminescent bacteria test. The results showed that both solid particles and aqueous/organic extracts of DWTR exhibited no toxicity to the bacterial luminescence and growth. The solid particles of DWTR even promoted bacterial luminescence, possibly because DWTR particles could act as a microbial carrier and provide nutrients for bacteria growth. Bacterial toxicity (either luminescence or growth) was observed from the solid phase and aqueous/organic extracts of sediments with or without DWTR addition. Further analysis showed that the solid phase toxicity was determined to be related mainly to the fixation of bacteria to fine particles and/or organic matter, and all of the observed inhibition resulting from aqueous/organic extracts was identified as non-significant. Moreover, DWTR addition not only had no adverse effect on the aqueous/organic extract toxicity of the sediment but also reduced the solid phase toxicity of the sediment. Overall, in practical application, the solid particles, the water-soluble substances transferred to surface water or the organic substances in DWTR had no toxicity or any delayed effect on bacteria in lakes, and DWTR can therefore be considered as a non-hazardous material. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. An experimental evaluation of two effective medium theories for ultrasonic wave propagation in concrete.

    PubMed

    Chaix, Jean-François; Rossat, Mathieu; Garnier, Vincent; Corneloup, Gilles

    2012-06-01

    This study compares ultrasonic wave propagation modeling and experimental data in concrete. As a consequence of its composition and manufacturing process, this material has a high elastic scattering (sand and aggregates) and air (microcracks and porosities) content. The behavior of the "Waterman-Truell" and "Generalized Self Consistent Method" dynamic homogenization models are analyzed in the context of an application for strong heterogeneous solid materials, in which the scatterers are of various concentrations and types. The experimental validations of results predicted by the models are carried out by making use of the phase velocity and the attenuation of longitudinal waves, as measured by an immersed transmission setup. The test specimen material has a cement-like matrix containing spherical inclusions of air or glass, with radius close to the ultrasonic wavelength. The models are adapted to the case of materials presenting several types of scattering particle, and allow the propagation of longitudinal waves to be described at the scale of materials such as concrete. The validity limits for frequency and for particle volume ratio can be approached through a comparison with experimental data. The potential of these homogenization models for the prediction of phase velocity and attenuation in strongly heterogeneous solids is demonstrated.

  15. Observation of solid–solid transitions in 3D crystals of colloidal superballs

    PubMed Central

    Meijer, Janne-Mieke; Pal, Antara; Ouhajji, Samia; Lekkerkerker, Henk N. W.; Philipse, Albert P.; Petukhov, Andrei V.

    2017-01-01

    Self-organization in anisotropic colloidal suspensions leads to a fascinating range of crystal and liquid crystal phases induced by shape alone. Simulations predict the phase behaviour of a plethora of shapes while experimental realization often lags behind. Here, we present the experimental phase behaviour of superball particles with a shape in between that of a sphere and a cube. In particular, we observe the formation of a plastic crystal phase with translational order and orientational disorder, and the subsequent transformation into rhombohedral crystals. Moreover, we uncover that the phase behaviour is richer than predicted, as we find two distinct rhombohedral crystals with different stacking variants, namely hollow-site and bridge-site stacking. In addition, for slightly softer interactions we observe a solid–solid transition between the two. Our investigation brings us one step closer to ultimately controlling the experimental self-assembly of superballs into functional materials, such as photonic crystals. PMID:28186101

  16. Polymeric CO: A new class of High Energy Density Material

    NASA Astrophysics Data System (ADS)

    Lipp, Magnus

    2005-03-01

    Covalently bonded extended phases of molecular solids made of first- and second-row elements at high pressures are a new class of material with advanced optical, mechanical and energetic properties. The existence of such extended solids has recently been demonstrated using diamond anvil cells in several systems, including N2, CO2, and CO. However, the microscopic quantities produced at the formidable high-pressure/temperature conditions have limited the characterization of their predicted novel properties including high-energy content. Here we present the first experimental evidence that these extended low-Z solids are indeed high energy density materials via milligram-scale high-pressure synthesis, recovery and characterization of polymeric CO (p-CO). This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

  17. Stable and metastable nanowires displaying locally controllable properties

    DOEpatents

    Sutter, Eli Anguelova; Sutter, Peter Werner

    2014-11-18

    Vapor-liquid-solid growth of nanowires is tailored to achieve complex one-dimensional material geometries using phase diagrams determined for nanoscale materials. Segmented one-dimensional nanowires having constant composition display locally variable electronic band structures that are determined by the diameter of the nanowires. The unique electrical and optical properties of the segmented nanowires are exploited to form electronic and optoelectronic devices. Using gold-germanium as a model system, in situ transmission electron microscopy establishes, for nanometer-sized Au--Ge alloy drops at the tips of Ge nanowires (NWs), the parts of the phase diagram that determine their temperature-dependent equilibrium composition. The nanoscale phase diagram is then used to determine the exchange of material between the NW and the drop. The phase diagram for the nanoscale drop deviates significantly from that of the bulk alloy.

  18. In situ study of LaY2Ni9 compound as Ni MH negative-electrode material

    NASA Astrophysics Data System (ADS)

    Latroche, M.; Isnard, O.

    2008-03-01

    The behavior of a Ni-MH (metal hydride) negative composite electrode made of LaY2Ni9 active material has been studied dynamically using in situ neutron diffraction during a complete charge-discharge electrochemical cycle. From the analysis of the collected diffraction patterns, the phase identity, phase amount variations and cell volume evolutions have been determined as a function of the electrochemical state of (dis)charge. The active material shows a typical two-phase behavior with equilibrium between a hydrogen-poor α phase and a hydrogen-rich β one. The lower electrochemical reversible capacity as compared to solid-gas properties has been interpreted in terms of hydrogen gas evolving during charge and kinetic limitation due to slow β to α transformation during discharge, which hinders high discharge rates.

  19. In vitro toxicity test of nano-sized magnesium oxide synthesized via solid-phase transformation

    NASA Astrophysics Data System (ADS)

    Zheng, Jun; Zhou, Wei

    2018-04-01

    Nano-sized magnesium oxide (MgO) has been a promising potential material for biomedical pharmaceuticals. In the present investigation, MgO nanoparticles synthesized through in-situ solid-phase transformation based on the previous work (nano-Mg(OH)2 prepared by precipitation technique) using magnesium nitrate and sodium hydroxide. The phase structure and morphology of the MgO nanoparticles are characterized by X-ray powder diffraction (XRD), selected area electronic diffraction (SAED) and transmission electron microscopy (TEM) respectively. In vitro hemolysis tests are adopted to evaluate the toxicity of the synthesized nano-MgO. The results evident that nano-MgO with lower concentration is slightly hemolytic, and with concentration increasing nano-MgO exhibit dose-responsive hemolysis.

  20. Many-Body Perturbation Theory for Understanding Optical Excitations in Organic Molecules and Solids

    NASA Astrophysics Data System (ADS)

    Sharifzadeh, Sahar

    Organic semiconductors are promising as light-weight, flexible, and strongly absorbing materials for next-generation optoelectronics. The advancement of such technologies relies on understanding the fundamental excited-state properties of organic molecules and solids, motivating the development of accurate computational approaches for this purpose. Here, I will present first-principles many-body perturbation theory (MBPT) calculations aimed at understanding the spectroscopic properties of select organic molecules and crystalline semiconductors, and improving these properties for enhanced photovoltaic performance. We show that for both gas-phase molecules and condensed-phase crystals, MBPT within the GW/BSE approximation provides quantitative accuracy of transport gaps extracted from photoemission spectroscopy and conductance measurements, as well as with measured polarization-dependent optical absorption spectra. We discuss the implications of standard approximations within GW/BSE on accuracy of these results. Additionally, we demonstrate significant exciton binding energies and charge-transfer character in the crystalline systems, which can be controlled through solid-state morphology or change of conjugation length, suggesting a new strategy for the design of optoelectronic materials. We acknowledge NSF for financial support; NERSC and Boston University for computational resources.

  1. Metal-semiconductor phase transition of order arrays of VO2 nanocrystals

    NASA Astrophysics Data System (ADS)

    Lopez, Rene; Suh, Jae; Feldman, Leonard; Haglund, Richard

    2004-03-01

    The study of solid-state phase transitions at nanometer length scales provides new insights into the effects of material size on the mechanisms of structural transformations. Such research also opens the door to new applications, either because materials properties are modified as a function of particle size, or because the nanoparticles interact with a surrounding matrix material, or with each other. In this paper, we describe the formation of vanadium dioxide nanoparticles in silicon substrates by pulsed laser deposition of ion beam lithographically selected sites and thermal processing. We observe the collective behavior of 50 nm diameter VO2 oblate nanoparticles, 10 nm high, and ordered in square arrays with arbitrary lattice constant. The metal-semiconductor-transition of the VO2 precipitates shows different features in each lattice spacing substrate. The materials are characterized by electron microscopy, x-ray diffraction, Rutherford backscattering. The features of the phase transition are studied via infrared optical spectroscopy. Of particular interest are the enhanced scattering and the surface plasmon resonance when the particles reach the metallic state. This resonance amplifies the optical contrast in the range of near-infrared optical communication wavelengths and it is altered by the particle-particle coupling as in the case of noble metals. In addition the VO2 nanoparticles exhibit sharp transitions with up to 50 K of hysteresis, one of the largest values ever reported for this transition. The optical properties of the VO2 nanoarrays are correlated with the size of the precipitates and their inter-particle distance. Nonlinear and ultra fast optical measurements have shown that the transition is the fastest known solid-solid transformation. The VO2 nanoparticles show the same bulk property, transforming in times shorter than 150 fs. This makes them remarkable candidates for ultrafast optical and electronic switching applications.

  2. Conformational polymorphism and thermochemical analysis of 5,5' ''-bis[(2,2,5,5-tetramethyl-1-aza-2,5-disila-1-cyclopentyl)ethyl]-2,2':5',2' ':5' ',2' ''-quaterthiophene.

    PubMed

    Muguruma, Hitoshi; Hotta, Shu

    2006-11-23

    The titled compound exists as two polymorphic solid phases (denoted form-I and form-II). Form-I obtained by as-synthesized material is a more stable phase. Form-II is a less stable phase. Spontaneous solid-solid transformation from form-II to form-I is observed in the temperature range between room temperature and the melting point of form-I (Tm = 156.5 degrees C), and its activation energy is estimated to be 96 kJ mol-1 by Arrhenius plot. The solid-solute-solid transformation (recrystallization from solution) from form-II to form-I is also observed. In contrast, form-II is obtained only by a solid-melt-solid transformation from form-I. Therefore, the system of two polymorphs is monotropic. The solid-state NMR measurement shows that form-I has the molecular conformation of complete S-syn-anti-syn in the oligothiophene backbone, whereas form-II has that of S-all-anti. With the solution NMR data, the polymorphism could not be observed. Therefore, the polymorphs originate from the different molecular packing involving the conformational change of the molecule. This unique property is attributed to the extra bulky terminal groups of the compounds. However, despite the extra bulky terminal groups, the mentioned polymorphism is not observed in the titled compound analogue which has S-all-anti conformation (like form-II).

  3. Microstructural Evolution and Phase Formation in 2nd-Generation Refractory-Based High Entropy Alloys

    PubMed Central

    Eshed, Eyal; Larianovsky, Natalya; Kovalevsky, Alexey; Popov, Vladimir; Gorbachev, Igor; Popov, Vladimir; Katz-Demyanetz, Alexander

    2018-01-01

    Refractory-based high entropy alloys (HEAs) of the 2nd-generation type are new intensively-studied materials with a high potential for structural high-temperature applications. This paper presents investigation results on microstructural evolution and phase formation in as-cast and subsequently heat-treated HEAs at various temperature-time regimes. Microstructural examination was performed by means of scanning electron microscopy (SEM) combined with the energy dispersive spectroscopy (EDS) mode of electron probe microanalysis (EPMA) and qualitative X-ray diffraction (XRD). The primary evolutionary trend observed was the tendency of Zr to gradually segregate as the temperature rises, while all the other elements eventually dissolve in the BCC solid solution phase once the onset of Laves phase complex decomposition is reached. The performed thermodynamic modelling was based on the Calculation of Phase Diagrams method (CALPHAD). The BCC A2 solid solution phase is predicted by the model to contain increasing amounts of Cr as the temperature rises, which is in perfect agreement with the actual results obtained by SEM. However, the model was not able to predict the existence of the Zr-rich phase or the tendency of Zr to segregate and form its own solid solution—most likely as a result of the Zr segregation trend not being an equilibrium phenomenon. PMID:29360763

  4. Research on ignition and flame spread of solid materials in Japan

    NASA Technical Reports Server (NTRS)

    Ito, Kenichi; Fujita, Osamu

    1995-01-01

    Fire safety is one of the main concerns for crewed missions such as the space station. Materials used in spacecraft may burn even if metalic. There are severe restrictions on the materials used in spacecraft from the view of fire safety. However, such restrictions or safety standards are usually determined based on experimental results under normal gravity, despite large differences between the phenomena under normal and microgravity. To evaluate the appropriateness of materials for use in space, large amount of microgravity fire-safety combustion data is urgently needed. Solid material combustion under microgravity, such as ignition and flame spread, is a relatively new research field in Japan. As the other reports in this workshop describe, most of microgravity combustion research in Japan is droplet combustion as well as some research on gas phase combustion. Since JAMIC, the Japan Microgravity Center, (which offers 10 seconds microgravity time) opened in 1992, microgravity combustion research is robust, and many drop tests relating to solid combustion (paper combustion, cotton string combustion, metal combustion with Aluminium or Magnesium) have been performed. These tests proved that the 10 seconds of microgravity time at JAMIC is useful for solid combustion research. Some experiments were performed before JAMIC opened. For example, latticed paper was burned under microgravity by using a 50 m drop tower to simulate porous material combustion under microgravity. A 50 m tower provides only 2 seconds microgravity time however, and it was not long enough to investigate the solid combustion phenomena.

  5. New environmentally friendly MSPD solid support based on golden mussel shell: characterization and application for extraction of organic contaminants from mussel tissue.

    PubMed

    Rombaldi, Caroline; de Oliveira Arias, Jean Lucas; Hertzog, Gabriel Ianzer; Caldas, Sergiane Souza; Vieira, João P; Primel, Ednei Gilberto

    2015-06-01

    The use of golden mussel shells as a solid support in vortex-assisted matrix solid-phase dispersion (MSPD) was evaluated for the first time for extraction of residues of 11 pesticides and nine pharmaceutical and personal care products from mussel tissue samples. After they had been washed, dried, and milled, the mussel shells were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, infrared spectroscopy, and Brunauer-Emmett-Teller analysis. The MSPD procedure with analysis by liquid chromatography-tandem mass spectrometry allowed the determination of target analytes at trace concentrations (nanograms per gram), with mean recoveries ranging from 61 to 107 % and relative standard deviations lower than 18 %. The optimized method consisted of dispersion of 0.5 g of mussel tissue, 0.5 g of NaSO4, and 0.5 g of golden mussel shell for 5 min, and subsequent extraction with 5 mL of ethyl acetate. The matrix effect was evaluated, and a low effect was found for all compounds. The results showed that mussel shell is an effective material and a less expensive material than materials that have traditionally been used, i.e., it may be used in the MSPD dispersion step during the extraction of pesticides and pharmaceutical and personal care products from golden mussel tissues. Graphical Abstract Vortex-assited matrix solid-phase dispersion for extraction of 11 pesticides and 9 PPCPs care products from mussel tissue samples.

  6. Computational understanding of Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Urban, Alexander; Seo, Dong-Hwa; Ceder, Gerbrand

    2016-03-01

    Over the last two decades, computational methods have made tremendous advances, and today many key properties of lithium-ion batteries can be accurately predicted by first principles calculations. For this reason, computations have become a cornerstone of battery-related research by providing insight into fundamental processes that are not otherwise accessible, such as ionic diffusion mechanisms and electronic structure effects, as well as a quantitative comparison with experimental results. The aim of this review is to provide an overview of state-of-the-art ab initio approaches for the modelling of battery materials. We consider techniques for the computation of equilibrium cell voltages, 0-Kelvin and finite-temperature voltage profiles, ionic mobility and thermal and electrolyte stability. The strengths and weaknesses of different electronic structure methods, such as DFT+U and hybrid functionals, are discussed in the context of voltage and phase diagram predictions, and we review the merits of lattice models for the evaluation of finite-temperature thermodynamics and kinetics. With such a complete set of methods at hand, first principles calculations of ordered, crystalline solids, i.e., of most electrode materials and solid electrolytes, have become reliable and quantitative. However, the description of molecular materials and disordered or amorphous phases remains an important challenge. We highlight recent exciting progress in this area, especially regarding the modelling of organic electrolytes and solid-electrolyte interfaces.

  7. Nano powders, components and coatings by plasma technique

    DOEpatents

    McKechnie, Timothy N [Brownsboro, AL; Antony, Leo V. M. [Huntsville, AL; O'Dell, Scott [Arab, AL; Power, Chris [Guntersville, AL; Tabor, Terry [Huntsville, AL

    2009-11-10

    Ultra fine and nanometer powders and a method of producing same are provided, preferably refractory metal and ceramic nanopowders. When certain precursors are injected into the plasma flame in a reactor chamber, the materials are heated, melted and vaporized and the chemical reaction is induced in the vapor phase. The vapor phase is quenched rapidly to solid phase to yield the ultra pure, ultra fine and nano product. With this technique, powders have been made 20 nanometers in size in a system capable of a bulk production rate of more than 10 lbs/hr. The process is particularly applicable to tungsten, molybdenum, rhenium, tungsten carbide, molybdenum carbide and other related materials.

  8. Nano powders, components and coatings by plasma technique

    NASA Technical Reports Server (NTRS)

    McKechnie, Timothy N. (Inventor); Antony, Leo V. M. (Inventor); O'Dell, Scott (Inventor); Power, Chris (Inventor); Tabor, Terry (Inventor)

    2009-01-01

    Ultra fine and nanometer powders and a method of producing same are provided, preferably refractory metal and ceramic nanopowders. When certain precursors are injected into the plasma flame in a reactor chamber, the materials are heated, melted and vaporized and the chemical reaction is induced in the vapor phase. The vapor phase is quenched rapidly to solid phase to yield the ultra pure, ultra fine and nano product. With this technique, powders have been made 20 nanometers in size in a system capable of a bulk production rate of more than 10 lbs/hr. The process is particularly applicable to tungsten, molybdenum, rhenium, tungsten carbide, molybdenum carbide and other related materials.

  9. Simulation of radial solute segregation in vertical Bridgman growth of pyridine-doped benzene, a surrogate for binary organic nonlinear optical materials

    NASA Astrophysics Data System (ADS)

    Lee, Hanjie; Pearlstein, Arne J.

    2000-09-01

    We present steady axisymmetric computations of solute distributions and radial segregation for vertical Bridgman growth of pyridine-doped benzene, a binary aromatic system with anisotropic solid-phase thermal conductivity, that serves as a model of solute transport in crystal growth of organic nonlinear optical materials. The radial variation of solid-phase mass fraction ( Cs) of pyridine, which is rejected at the growing interface, depends strongly on growth conditions. High growth velocities tend to increase Cs near the centerline, the ampoule wall, or both, and low growth velocities give more nearly uniform radial distributions. The maximum ampoule-wall temperature gradient also affects radial segregation, with convex-to-the-liquid interfaces at small temperature gradients being associated with radially monotonic Cs distributions, and ridged interfaces at higher gradients being associated with nonmonotonic distributions having maxima at the centerline and ampoule wall. Nonuniformity is strongly determined by both interface shape and the nature of the flow near the interface. Solute is transported down to the interface by a large toroidal vortex, and swept radially inward to the centerline by a second, flattened toroidal cell. When the interface is depressed at its junction with the ampoule wall, rejected solute accumulates in the overlying liquid, where convection is relatively weak, resulting in local solute enrichment of the solid. Computations at normal and zero gravity show that for two very similar interface shapes, a maximum in the radial solid-phase solute distribution at the ampoule wall is associated with the interface shape, while the maximum on the centerline is associated with sweeping of solute to the centerline by a vortical flow on the interface. We also show that radial solute segregation depends significantly on whether account is taken of the anisotropy of the solid-phase thermal conductivity. Finally, the computations provide guidance as to the minimum ampoule length required to produce an axially uniform solute distribution over at least part of the length of a boule.

  10. Physics and Chemistry of Earth Materials

    NASA Astrophysics Data System (ADS)

    Navrotsky, Alexandra

    1994-11-01

    Stressing the fundamental solid state behavior of minerals, and emphasizing both theory and experiment, this text surveys the physics and chemistry of earth materials. The author begins with a systematic tour of crystal chemistry of both simple and complex structures (with completely new structural drawings) and discusses how to obtain structural and thermodynamic information experimentally. Dr. Navrotsky also reviews the quantitative concepts of chemical bonding--band theory, molecular orbit and ionic models. She then covers physical properties and relates microscopic features to macroscopic thermodynamic behavior and treats high pressure phase transitions, amorphous materials and solid state reactions. The author concludes with a look at the interface between mineral physics and materials science. Highly illustrated throughout, this book fills the gap between undergraduate texts and specialized review volumes and is appropriate for students and researchers in earth science and materials science.

  11. Structure and dielectric properties of Na0.5Bi0.5TiO3-CaTiO3 solid solutions

    NASA Astrophysics Data System (ADS)

    Birks, E.; Dunce, M.; Ignatans, R.; Kuzmin, A.; Plaude, A.; Antonova, M.; Kundzins, K.; Sternberg, A.

    2016-02-01

    Despite wide studies of Na0.5Bi0.5TiO3, structure of this material and its connection with the observed physical properties still raise numerous questions due to mutually contradicting results obtained. Here, structure and dielectric properties of poled and unpoled Na0.5Bi0.5TiO3-CaTiO3 solid solutions are studied, projecting the obtained concentration dependence of structure and dielectric properties on pure Na0.5Bi0.5TiO3 as the end member of this material group. X-ray diffraction patterns for Na0.5Bi0.5TiO3-CaTiO3 solid solutions reveal dominating of an orthorhombic Pnma phase, even for the compositions approaching the end composition (Na0.5Bi0.5TiO3), whereas structure of pure Na0.5Bi0.5TiO3 can be considered, assuming coexistence of rhombohedral and orthorhombic phases. This allows one to avoid appearance of a large difference of rhombohedral distortions between the unpoled and poled Na0.5Bi0.5TiO3, if the rhombohedral distortion is calculated as for single R3c phase. Features of dielectric permittivity, corresponding to the observed structural phase transition, are identified. It is discussed that the rhombohedral R3c phase is responsible for appearance of the frequency-dependent shoulder of dielectric permittivity temperature dependence, characteristic for unpoled Na0.5Bi0.5TiO3.

  12. Crystal growth of argyrodite-type phases Cu 8-xGeS 6-xI x and Cu 8-xGeSe 6-xI x (0⩽ x⩽0.8)

    NASA Astrophysics Data System (ADS)

    Tomm, Yvonne; Schorr, Susan; Fiechter, Sebastian

    2008-04-01

    The growth of single crystalline argyrodites of type Cu 8-xGeX 6-xY x ( X=S, Se; Y=I) is reported. These materials undergo solid-solid phase transitions at temperatures ranging from 30 to 90 °C. In the high temperature phase, Cu 8GeS 6 crystallizes in the cubic space group F4¯3m. In the low temperature phase, the compound is present in the orthorhombic space group Pmn2 1. Cu 8GeSe 6 appears exclusively in the hexagonal space groups P6 3mc or P6 3cm, respectively. Single crystals of these argyrodites were obtained by chemical vapor transport in a temperature gradient Δ T=980-950 and Δ T=700-620 °C for sulfides and selenides, respectively. As a result of the growth process, the high temperature phase remains stable even at ambient temperature by incorporation of the transport agent iodine during the growth process. As determined by energy dispersive X-ray analysis (EDAX), the composition of the sulfide crystals grown ranges from Cu 8GeS 6 to Cu 7.16GeS 5.16I 0.84. The selenide crystallizes as Cu 7.69GeSe 5.69I 0.31. In contrast, the solid state reaction of the elements Cu, Ge and X produces a material in the low temperature modification with an ideal composition of Cu 8GeX 6.

  13. Ultrafast studies of shock-induced melting and phase transitions at LCLS

    NASA Astrophysics Data System (ADS)

    McMahon, Malcolm

    The study of shock-induced phase transitions, which is vital to the understanding of material response to rapid pressure changes, dates back to the 1950s, when Bankcroft et al reported a transition in iron. Since then, many transitions have been reported in a wide range of materials, but, due to the lack of sufficiently bright x-ray sources, the structural details of these new phases has been notably lacking. While the development of nanosecond in situ x-ray diffraction has meant that lattice-level studies of such phenomena have become possible, including studies of the phase transition reported 60 years ago in iron, the quality of the diffraction data from such studies is noticeably poorer than that obtained from statically-compressed samples on synchrotrons. The advent of x-ray free electron lasers (XFELs), such as the LCLS, has resulted in an unprecedented improvement in the quality of diffraction data that can be obtained from shock-compressed matter. Here I describe the results from three recent experiment at the LCLS that looked at the solid-solid and solid-liquid phase transitions in Sb, Bi and Sc using single 50 fs x-ray exposures. The results provide new insight into the structural changes and melting induced by shock compression. This work is supported by EPSRC under Grant No. EP/J017051/1. Use of the LCLS, SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515.

  14. Electronic Structure of CO2 at High Pressure

    NASA Astrophysics Data System (ADS)

    Shieh, S. R.; Jarrige, I.; Hiraoka, N.; Cai, Y.

    2009-12-01

    Carbon dioxide (CO2) is one of the important planetary materials that can be found in the Venus, Earth and Mars. Therefore, the behavior of CO2 under different pressure and temperature conditions is of great importance for understanding the evolution of these planets. Recent studies showed that there are six solid phases and one amorphous phase of CO2 found at various pressure and temperature conditions. This indicates that CO2 may exhibit different forms within planetary interiors. To better understand the behavior of CO2 polymorphs and their interactions with other materials it is necessary to study the electronic structures of CO2 polymorphs. Here we report the electronic structures of CO2-I and -III at high pressure and room temperature. The high-pressure inelastic scattering measurements of CO2 were conducted at beamline 12XU, SPring-8. A monochromatic beam with incident energy about 10 KeV was focused by a pair of KB mirrors to a size of 20 by 30 μm2. The inelastic x-ray scattering photons were collected at about 35 degrees and a solid state Si detector with resolution of about 1.4eV was used. Each spectrum was collected for 8-20 hours. Our results show that a strong pi bond, together with weak sigma bonds of oxygen K-edge were observed in CO2-I and -III phase. For the carbon K-edge of CO2-I, only a single pi bond was observed. This suggests that the molecular solid phase of CO2-I exhibits a gas-like phase instead of a crystal-like phase. Similar results were also observed form CO2-III.

  15. Amorphous and nanocrystalline luminescent Si and Ge obtained via a solid-state chemical metathesis synthesis route

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    McMillan, Paul F.; Gryko, Jan; Bull, Craig

    A new solid-state metathesis synthesis route was applied to obtain bulk samples of amorphous or microcrystalline Si and Ge. The method involves reaction of Zintl phases such as NaSi or NaGe, with ammonium or metal (e.g., CuCl, CoBr{sub 2}) halides. The driving force for the solid-state reaction is provided by the formation of alkali halides and the transition metals or metal silicides, or gaseous ammonia and hydrogen. The semiconductors were purified by washing to remove other solid products. The amorphous semiconductors were obtained in bulk form from reactions carried out at 200-300{sup o}C. Syntheses at higher temperatures gave rise tomore » microcrystalline semiconductors, or to micro-/nanocrystalline particles contained within the amorphous material. Similar crystalline/amorphous composites were obtained after heat treatment of bulk amorphous materials.« less

  16. Magnetic self-orientation of lyotropic hexagonal phases based on long chain alkanoic (fatty) acids.

    PubMed

    Douliez, Jean-Paul

    2010-07-06

    It is presently shown that long chain (C14, C16, and C18) alkanoic (saturated fatty) acids can form magnetically oriented hexagonal phases in aqueous concentrated solutions in mixtures with tetrabutylammonium (TBAOH) as the counterion. The hexagonal phase occurred for a molar ratio, alkanoic acid/TBAOH, higher than 1, i.e., for an excess of fatty acid. The hexagonal phase melted to an isotropic phase (micelles) upon heating at a given temperature depending on the alkyl chain length. The self-orientation of the hexagonal phase occurred upon cooling from the "high-temperature" isotropic phase within the magnetic field. The long axis of the hexagonal phase was shown to self-orient parallel to the magnetic field as evidenced by deuterium solid-state NMR. This finding is expected to be of interest in the field of structural biology and materials chemistry for the synthesis of oriented materials.

  17. Two-Step Vapor/Liquid/Solid Purification

    NASA Technical Reports Server (NTRS)

    Holland, L. R.

    1986-01-01

    Vertical distillation system combines in single operation advantages of multiple zone refining with those of distillation. Developed specifically to load Bridgman-Stockbarger (vertical-solidification) growth ampoules with ultrapure tellurium and cadmium, system, with suitable modifications, serves as material refiner. In first phase of purification process, ampoule heated to drive off absorbed volatiles. Second phase, evaporator heated to drive off volatiles in charge. Third phase, slowly descending heater causes distillation from evaporator to growing crystal in ampoule.

  18. Mesoporous carbons and polymers

    DOEpatents

    Bell, William; Dietz, Steven

    2001-01-01

    A mesoporous material prepared by polymerizing a resorcinol/formaldehyde system from an aqueous solution containing resorcinol, formaldehyde and a surfactant and optionally pyrolyzing the polymer to form a primarily carbonaceous solid. The material has an average pore size between 4 and 75 nm and is suitable for use in liquid-phase surface limited applications, including sorbent, catalytic, and electrical applications.

  19. Target design for materials processing very far from equilibrium

    NASA Astrophysics Data System (ADS)

    Barnard, John J.; Schenkel, Thomas

    2016-10-01

    Local heating and electronic excitations can trigger phase transitions or novel material states that can be stabilized by rapid quenching. An example on the few nanometer scale are phase transitions induced by the passage of swift heavy ions in solids where nitrogen-vacancy color centers form locally in diamonds when ions heat the diamond matrix to warm dense matter conditions at 0.5 eV. We optimize mask geometries for target materials such as silicon and diamond to induce phase transitions by intense ion pulses (e. g. from NDCX-II or from laser-plasma acceleration). The goal is to rapidly heat a solid target volumetrically and to trigger a phase transition or local lattice reconstruction followed by rapid cooling. The stabilized phase can then be studied ex situ. We performed HYDRA simulations that calculate peak temperatures for a series of excitation conditions and cooling rates of crystal targets with micro-structured masks. A simple analytical model, that includes ion heating and radial, diffusive cooling, was developed that agrees closely with the HYDRA simulations. The model gives scaling laws that can guide the design of targets over a wide range of parameters including those for NDCX-II and the proposed BELLA-i. This work was performed under the auspices of the U.S. DOE under contracts DE-AC52-07NA27344 (LLNL), DE-AC02-05CH11231 (LBNL) and was supported by the US DOE Office of Science, Fusion Energy Sciences. LLNL-ABS-697271.

  20. Understanding the bond-energy, hardness, and adhesive force from the phase diagram via the electron work function

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lu, Hao; Huang, Xiaochen; Li, Dongyang, E-mail: dongyang.li@ualberta.ca

    2014-11-07

    Properties of metallic materials are intrinsically determined by their electron behavior. However, relevant theoretical treatment involving quantum mechanics is complicated and difficult to be applied in materials design. Electron work function (EWF) has been demonstrated to be a simple but fundamental parameter which well correlates properties of materials with their electron behavior and could thus be used to predict material properties from the aspect of electron activities in a relatively easy manner. In this article, we propose a method to extract the electron work functions of binary solid solutions or alloys from their phase diagrams and use this simple approachmore » to predict their mechanical strength and surface properties, such as adhesion. Two alloys, Fe-Ni and Cu-Zn, are used as samples for the study. EWFs extracted from phase diagrams show same trends as experimentally observed ones, based on which hardness and surface adhesive force of the alloys are predicted. This new methodology provides an alternative approach to predict material properties based on the work function, which is extractable from the phase diagram. This work may also help maximize the power of phase diagram for materials design and development.« less

  1. Propagation of a Chemical Reaction through Heterogeneous Lithium- Polytetrafluoroethylene Mixtures

    DTIC Science & Technology

    1975-12-11

    Condensed Phases ........... ............... 9 1.2.1 Lithium-Gas Surface Reactions. .......... 10 1.2.2 Composite Solid Propellant Combustion. . .. 13...f:- the o:cu:=ence _A a surface reaction was developed, but no analyti7al reaction zate model was presented- 1.2.2 Composite S’-lid Propellant...Combustion Composite solid propellants are plastic-like materials consisting of small oxidizer particles embedded in a fuel matrix. Ammonium perchlorate is

  2. Silicon Nanostructures, Excitonic Interactions, Laser Consequences

    DTIC Science & Technology

    2008-07-11

    etching using an anodized aluminum oxide membrane as mask. The results described here lay a solid foundation for the next phase of development aimed at...achieved though reactive-ion-etching using an anodized aluminum oxide membrane as mask. The results described here lay a solid foundation for the next...Materials, April 4, 2006 issue). 6. Aijun Yin, Marian Tzolov, David Cardimona and Jimmy Xu, "Fabrication of Highly Ordered Anodic Aluminum Oxide

  3. Solid state synthesis of poly(dichlorophosphazene)

    DOEpatents

    Allen, Christopher W.; Hneihen, Azzam S.; Peterson, Eric S.

    2001-01-01

    A method for making poly(dichlorophosphazene) using solid state reactants is disclosed and described. The present invention improves upon previous methods by removing the need for chlorinated hydrocarbon solvents, eliminating complicated equipment and simplifying the overall process by providing a "single pot" two step reaction sequence. This may be accomplished by the condensation reaction of raw materials in the melt phase of the reactants and in the absence of an environmentally damaging solvent.

  4. Yield stress in amorphous solids: A mode-coupling-theory analysis

    NASA Astrophysics Data System (ADS)

    Ikeda, Atsushi; Berthier, Ludovic

    2013-11-01

    The yield stress is a defining feature of amorphous materials which is difficult to analyze theoretically, because it stems from the strongly nonlinear response of an arrested solid to an applied deformation. Mode-coupling theory predicts the flow curves of materials undergoing a glass transition and thus offers predictions for the yield stress of amorphous solids. We use this approach to analyze several classes of disordered solids, using simple models of hard-sphere glasses, soft glasses, and metallic glasses for which the mode-coupling predictions can be directly compared to the outcome of numerical measurements. The theory correctly describes the emergence of a yield stress of entropic nature in hard-sphere glasses, and its rapid growth as density approaches random close packing at qualitative level. By contrast, the emergence of solid behavior in soft and metallic glasses, which originates from direct particle interactions is not well described by the theory. We show that similar shortcomings arise in the description of the caging dynamics of the glass phase at rest. We discuss the range of applicability of mode-coupling theory to understand the yield stress and nonlinear rheology of amorphous materials.

  5. Extended Solids of Carbon Monoxide formed from Re2(CO)12

    NASA Astrophysics Data System (ADS)

    Ciezak-Jenkins, Jennifer

    Extended solids are formed from simple molecular gases under extreme P/T and are of considerable interest as high-energy-density materials. It has been postulated that a transformation from a single-bonded polymeric-like material back to the more stable triply-bonded diatomic phase would be a highly exothermic process yielding large amounts of energy. The extended polymeric solid of CO was first reported and recovered from high pressure conditions in 2005. Although the material was found to have potentially interesting energetic properties, it showed a number of stability issues, degrading into CO2 and graphitic carbon over 3 to 5 days. As such, our lab has been focused on the identification of methods to increase the metastability of the recovered solid. Metal carbonyls offer one such route for stabilization. In this talk, our progress in the study of the synthesis, characterization, and recovery of extended solids of CO starting from Re2(CO)12\\ to pressures near 50 GPa will be presented. I will discuss the analysis and the implications of these results. New opportunities and challenges that have arisen in the course of our studies that will be pursued in the future will also be presented. Ref

  6. Pipette-tip solid-phase extraction using polypyrrole as efficient adsorbent for extraction of avermectins and milbemycins in milk.

    PubMed

    Florez, Diego Hernando Ângulo; Teixeira, Roseane Andrade; da Silva, Ricky Cássio Santos; Pires, Bruna Carneiro; Dutra, Flávia Viana Avelar; Borges, Keyller Bastos

    2018-05-01

    In this work, we developed a HPLC method for the multidetermination of avermectins (AVM) (abamectin-ABA 1b and ABA 1a, eprinomectin-EPR, and ivermectin-IVM) and milbemycins (moxidectin-MOX) in milk samples using polypyrrole (PPy) as adsorbent material in pipette-tip solid-phase extraction (PT-PPy-SPE). PPy was characterized by scanning electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, and X-ray diffraction and the data agreed with the literature. The sample preparation included the clean-up of the milk by protein precipitation (PP) with acetonitrile and extraction of the analytes by PT-PPy-SPE. The chromatographic method was developed in reverse phase and isocratic mode with flow rate at 1.2 mL min -1 and ultraviolet detection at 250 nm. The mobile phase composition was acetonitrile:methanol:water (55:25:20, v/v/v). The studied parameters and the optimized conditions for the sample preparation were washing solvent (300 μL water), volume and type of eluent (500 μL methanol), volume and pH of sample (1 mL and pH 10), amount of adsorbent material (50 mg PPy), and without addition of salt (NaCl). The method was linear over the concentration range from 20 to 3000 ng mL -1 with coefficients of correlation (r) ≥ 0.99 for all analytes and recoveries around 100%. The method developed and validated was used for the analyses of real milk samples from cow treated with Ivomec ® (IVM 3.5%), in which were found 21.51 ± 2.94 ng mL -1 of IVM. Finally, the results proved that PT-PPy-SPE coupled to HPLC-UV was economical, simple, and easy-to-perform technique. Graphical abstract Pipette-tip solid phase extraction using polypirrole as adsorbent material for determination of avermectins and milbemycins in milk.

  7. Couplings

    NASA Astrophysics Data System (ADS)

    Stošić, Dušan; Auroux, Aline

    Basic principles of calorimetry coupled with other techniques are introduced. These methods are used in heterogeneous catalysis for characterization of acidic, basic and red-ox properties of solid catalysts. Estimation of these features is achieved by monitoring the interaction of various probe molecules with the surface of such materials. Overview of gas phase, as well as liquid phase techniques is given. Special attention is devoted to coupled calorimetry-volumetry method. Furthermore, the influence of different experimental parameters on the results of these techniques is discussed, since it is known that they can significantly influence the evaluation of catalytic properties of investigated materials.

  8. Gas dispersion and immobile gas volume in solid and porous particle biofilter materials at low air flow velocities.

    PubMed

    Sharma, Prabhakar; Poulsen, Tjalfe G

    2010-07-01

    Gas-phase dispersion in granular biofilter materials with a wide range of particle sizes was investigated using atmospheric air and nitrogen as tracer gases. Two types of materials were used: (1) light extended clay aggregates (LECA), consisting of highly porous particles, and (2) gravel, consisting of solid particles. LECA is a commercial material that is used for insulation, as a soil conditioner, and as a carrier material in biofilters for air cleaning. These two materials were selected to have approximately the same particle shape. Column gas transport experiments were conducted for both materials using different mean particle diameters, different particle size ranges, and different gas flow velocities. Measured breakthrough curves were modeled using the advection-dispersion equation modified for mass transfer between mobile and immobile gas phases. The results showed that gas dispersivity increased with increasing mean particle diameter for LECA but was independent of mean particle diameter for gravel. Gas dispersivity also increased with increasing particle size range for both media. Dispersivities in LECA were generally higher than for gravel. The mobile gas content in both materials increased with increasing gas flow velocity but it did not show any strong dependency on mean particle diameter or particle size range. The relative fraction of mobile gas compared with total porosity was highest for gravel and lowest for LECA likely because of its high internal porosity.

  9. Photoacoustic spectroscopy for chemical detection

    NASA Astrophysics Data System (ADS)

    Holthoff, Ellen L.; Pellegrino, Paul M.

    2012-06-01

    The Global War on Terror has made rapid detection and identification of chemical and biological agents a priority for Military and Homeland Defense applications. Reliable real-time detection of these threats is complicated by our enemy's use of a diverse range of materials. Therefore, an adaptable platform is necessary. Photoacoustic spectroscopy (PAS) is a useful monitoring technique that is well suited for trace detection of gaseous media. This method routinely exhibits detection limits at the parts-per-billion (ppb) or sub-ppb range. The versatility of PAS also allows for the investigation of solid and liquid analytes. Current research utilizes quantum cascade lasers (QCLs) in combination with an air-coupled solid-phase photoacoustic cell design for the detection of condensed phase material films deposited on a surface. Furthermore, variation of the QCL pulse repetition rate allows for identification and molecular discrimination of analytes based solely on photoacoustic spectra collected at different film depths.

  10. Two-dimensional fluid-filled closed-cell cellular solid as an acoustic metamaterial with negative index

    NASA Astrophysics Data System (ADS)

    Dorodnitsyn, V.; Van Damme, B.

    2016-04-01

    A concept for acoustic metamaterials consisting of a cellular medium with fluid-filled cells is fabricated and studied experimentally. In such a system, the fluid and solid structure explicitly interact, and elastic wave propagation is coupled to both phases. Focusing here on shear wave behavior, we confirm previous numerical studies in three steps. We first measure the material deformations pertaining to three qualitatively different shear wave modes in the frequency range below 3.5 kHz. We then measure the group velocity and demonstrate that, within a certain frequency interval, the group and phase velocity have opposite signs. This shows that the system acts as a negative-index metamaterial. Finally, we confirm the presence of band gaps due to the locally resonant behavior of the cell walls. The demonstrated concept of a closed, fluid-filled cellular material as an acoustic metamaterial opens a wide space for applications.

  11. Surface-modified multifunctional MIP nanoparticles.

    PubMed

    Moczko, Ewa; Poma, Alessandro; Guerreiro, Antonio; Perez de Vargas Sansalvador, Isabel; Caygill, Sarah; Canfarotta, Francesco; Whitcombe, Michael J; Piletsky, Sergey

    2013-05-07

    The synthesis of core-shell molecularly imprinted polymer nanoparticles (MIP NPs) has been performed using a novel solid-phase approach on immobilised templates. The same solid phase also acts as a protective functionality for high affinity binding sites during subsequent derivatisation/shell formation. This procedure allows for the rapid synthesis, controlled separation and purification of high-affinity materials, with each production cycle taking just 2 hours. The aim of this approach is to synthesise uniformly sized imprinted materials at the nanoscale which can be readily grafted with various polymers without affecting their affinity and specificity. For demonstration purposes we grafted anti-melamine MIP NPs with coatings which introduce the following surface characteristics: high polarity (PEG methacrylate); electro-activity (vinylferrocene); fluorescence (eosin acrylate); thiol groups (pentaerythritol tetrakis(3-mercaptopropionate)). The method has broad applicability and can be used to produce multifunctional imprinted nanoparticles with potential for further application in the biosensors, diagnostics and biomedical fields and as an alternative to natural receptors.

  12. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Coker, Eric Nicholas; Rodriguez, Mark A.; Ambrosini, Andrea

    Hydrogen and carbon monoxide may be produced using solar-thermal energy in two-stage reactions of water and carbon dioxide, respectively, over certain metal oxide materials. The most active materials observed experimentally for these processes are complex mixtures of ferrite and zirconia based solids, and it is not clear how far the ferrites, the zirconia, or a solid solution between the two participate in the change of oxidation state during the cycling. Identification of the key phases in the redox material that enable splitting is of paramount importance to developing a working model of the materials. A three-pronged approach was adopted here:more » computer modeling to determine thermodynamically favorable materials compositions, bench reactor testing to evaluate materials’ performance, and in-situ characterization of reactive materials to follow phase changes and identify the phases active for splitting. For the characterization and performance evaluation thrusts, cobalt ferrites were prepared by co-precipitation followed by annealing at 1400 °C. An in-situ X-ray diffraction capability was developed and tested, allowing phase monitoring in real time during thermochemical redox cycling. Key observations made for an un-supported cobalt ferrite include: 1) ferrite phases partially reduce to wustite upon heating to 1400 °C in helium; 2) exposing the material to air at 1100 °C causes immediate re-oxidation; 3) the re-oxidized material may be thermally reduced at 1400 °C under inert; 4) exposure of a reduced material to CO 2 results in gradual re-oxidation at 1100 °C, but minimization of background O 2-levels is essential; 5) even after several redox cycles, the lattice parameters of the ferrites remain constant, indicating that irreversible phase separation does not occur, at least over the first five cycles; 6) substituting chemical (hydrogen) reduction for thermal reduction resulted in formation of a CoFe metallic alloy. Materials were also evaluated for their CO 2-splitting performance in bench reactor systems utilizing chemical reduction in place of thermal reduction. These tests lead to the following general conclusions: 1) despite over-reduction of the cobalt ferrite phase to CoFe alloy on chemical reduction, splitting of CO 2 still occurs; 2) the kinetics of chemical reduction follow the sequence: un-supported < ZrO 2-supported < yttria-stabilized ZrO 2 (YSZ)-supported ferrite; 3) ferrite/YSZ re-oxidizes faster than ferrite/ZrO 2 under CO 2 in the range 400 – 700 °C. The temperature and pressure regimes in which the thermal reduction and water-splitting steps are thermodynamically favorable in terms of the enthalpy and entropy of oxide reduction, were determined. These metrics represent a useful design goal for any proposed water-splitting cycle. Applying this theoretical framework to available thermodynamic data, it was shown that none of the 105 binary oxide redox couples that were screened possess both energetically favorable reduction and oxidation steps. However, several driving forces, including low pressure and a large positive solid-state entropy of reduction of the oxide, have the potential to enable thermodynamically-favored two-step cycles.« less

  13. Simulation of the infiltration process of a ceramic open-pore body with a metal alloy in semi-solid state to design the manufacturing of interpenetrating phase composites

    NASA Astrophysics Data System (ADS)

    Schomer, Laura; Liewald, Mathias; Riedmüller, Kim Rouven

    2018-05-01

    Metal-ceramic Interpenetrating Phase Composites (IPC) belong to a special subcategory of composite materials and reveal enhanced properties compared to conventional composite materials. Currently, IPC are produced by infiltration of a ceramic open-pore body with liquid metal applying high pressure and I or high temperature to avoid residual porosity. However, these IPC are not able to gain their complete potential, because of structural damages and interface reactions occurring during the manufacturing process. Compared to this, the manufacturing of IPC using the semi-solid forming technology offers great perspectives due to relative low processing temperatures and reduced mechanical pressure. In this context, this paper is focusing on numerical investigations conducted by using the FLOW-3D software for gaining a deeper understanding of the infiltration of open-pore bodies with semi-solid materials. For flow simulation analysis, a geometric model and different porous media drag models have been used. They have been adjusted and compared to get a precise description of the infiltration process. Based on these fundamental numerical investigations, this paper also shows numerical investigations that were used for basically designing a semi-solid forming tool. Thereby, the development of the flow front and the pressure during the infiltration represent the basis of the evaluation. The use of an open and closed tool cavity combined with various geometries of the upper die shows different results relating to these evaluation arguments. Furthermore, different overflows were designed and its effects on the pressure at the end of the infiltration process were investigated. Thus, this paper provides a general guideline for a tool design for manufacturing of metal-ceramic IPC using semi-solid forming.

  14. Effects of Primary Processing Techniques and Significance of Hall-Petch Strengthening on the Mechanical Response of Magnesium Matrix Composites Containing TiO2 Nanoparticulates

    PubMed Central

    Meenashisundaram, Ganesh Kumar; Nai, Mui Hoon; Gupta, Manoj

    2015-01-01

    In the present study, Mg (1.98 and 2.5) vol % TiO2 nanocomposites are primarily synthesized utilizing solid-phase blend-press-sinter powder metallurgy (PM) technique and liquid-phase disintegrated melt deposition technique (DMD) followed by hot extrusion. Microstructural characterization of the synthesized Mg-TiO2 nanocomposites indicated significant grain refinement with DMD synthesized Mg nanocomposites exhibiting as high as ~47% for 2.5 vol % TiO2 NPs addition. X-ray diffraction studies indicated that texture randomization of pure Mg depends not only on the critical amount of TiO2 NPs added to the Mg matrix but also on the adopted synthesis methodology. Irrespective of the processing technique, theoretically predicted tensile yield strength of Mg-TiO2 nanocomposites was found to be primarily governed by Hall-Petch mechanism. Among the synthesized Mg materials, solid-phase synthesized Mg 1.98 vol % TiO2 nanocomposite exhibited a maximum tensile fracture strain of ~14.5%. Further, the liquid-phase synthesized Mg-TiO2 nanocomposites exhibited higher tensile and compression properties than those primarily processed by solid-phase synthesis. The tensile-compression asymmetry values of the synthesized Mg-TiO2 nanocomposite was found to be lower than that of pure Mg with solid-phase synthesized Mg 1.98 vol % TiO2 nanocomposite exhibiting as low as 1.06. PMID:28347063

  15. Arbuscular mycorrhizal fungi make a complex contribution to soil aggregation

    NASA Astrophysics Data System (ADS)

    McGee, Peter; Daynes, Cathal; Damien, Field

    2013-04-01

    Soil aggregates contain solid and fluid components. Aggregates develop as a consequence of the organic materials, plants and hyphae of arbuscular mycorrhizal (AM) fungi acting on the solid phase. Various correlative studies indicate hyphae of AM fungi enmesh soil particles, but their impact on the pore space is poorly understood. Hyphae may penetrate between particles, remove water from interstitial spaces, and otherwise re-arrange the solid phase. Thus we might predict that AM fungi also change the pore architecture of aggregates. Direct observations of pore architecture of soil, such as by computer-aided tomography (CT), is difficult. The refractive natures of solid and biological material are similar. The plant-available water in various treatments allows us to infer changes in pore architecture. Our experimental studies indicate AM fungi have a complex role in the formation and development of aggregates. Soils formed from compost and coarse subsoil materials were planted with mycorrhizal or non-mycorrhizal seedlings and the resultant soils compared after 6 or 14 months in separate experiments. As well as enmeshing particles, AM fungi were associated with the development of a complex pore space and greater pore volume. Even though AM fungi add organic matter to soil, the modification of pore space is not correlated with organic carbon. In a separate study, we visualised hyphae of AM fungi in a coarse material using CT. In this study, hyphae appeared to grow close to the surfaces of particles with limited ramification across the pore spaces. Hyphae of AM fungi appear to utilise soil moisture for their growth and development of mycelium. The strong correlation between moisture and hyphae has profound implications for soil aggregation, plant utilisation of soil water, and the distribution of water as water availability declines.

  16. Thermomechanical behavior of shape memory elastomeric composites

    NASA Astrophysics Data System (ADS)

    Ge, Qi; Luo, Xiaofan; Rodriguez, Erika D.; Zhang, Xiao; Mather, Patrick T.; Dunn, Martin L.; Qi, H. Jerry

    2012-01-01

    Shape memory polymers (SMPs) can fix a temporary shape and recover their permanent shape in response to environmental stimuli such as heat, electricity, or irradiation. Most thermally activated SMPs use the macromolecular chain mobility change around the glass transition temperature ( Tg) to achieve the shape memory (SM) effects. During this process, the stiffness of the material typically changes by three orders of magnitude. Recently, a composite materials approach was developed to achieve thermally activated shape memory effect where the material exhibits elastomeric response in both the temporary and the recovered configurations. These shape memory elastomeric composites (SMECs) consist of an elastomeric matrix reinforced by a semicrystalline polymer fiber network. The matrix provides background rubber elasticity while the fiber network can transform between solid crystals and melt phases over the operative temperature range. As such it serves as a reversible "switching phase" that enables shape fixing and recovery. Shape memory elastomeric composites provide a new paradigm for the development of a wide array of active polymer composites that utilize the melt-crystal transition to achieve the shape memory effect. This potentially allows for material systems with much simpler chemistries than most shape memory polymers and thus can facilitate more rapid material development and insertion. It is therefore important to understand the thermomechanical behavior and to develop corresponding material models. In this paper, a 3D finite-deformation constitutive modeling framework was developed to describe the thermomechanical behavior of SMEC. The model is phenomenological, although inspired by micromechanical considerations of load transfer between the matrix and fiber phases of a composite system. It treats the matrix as an elastomer and the fibers as a complex solid that itself is an aggregate of melt and crystal phases that evolve from one to the other during a temperature change. As such, the composite consists of an elastomer reinforced by a soft liquid at high temperature and a stiff solid at low temperature. The model includes a kinetic description of the non-isothermal crystallization and melting of the fibers during a temperature change. As the fibers transform from melt to crystal during cooling it is assumed that new crystals are formed in an undeformed state, which requires careful tracking of the kinematics of the evolving phases which comes at a significant computational cost. In order to improve the computational efficiency, an effective phase model (EPM) is adopted to treat the evolving crystal phases as an effective medium. A suite of careful thermomechanical experiments with a SMEC was carried out to calibrate various model parameters, and then to demonstrate the ability of the model to accurately capture the shape memory behavior of the SMEC system during complex thermomechanical loading scenarios. The model also identifies the effects of microstructural design parameters such as the fiber volume fraction.

  17. Critical Issues for Producing UHTC-Brazed Joints: Wetting and Reactivity

    NASA Astrophysics Data System (ADS)

    Passerone, A.; Muolo, M. L.; Valenza, F.

    2016-08-01

    A brief survey is presented of the most important interaction phenomena occurring at the solid-liquid interfaces in metal-ceramic systems at high temperatures, with special attention to the most recent developments concerning wetting and joining transition metals diborides. These phenomena are described and discussed from both the experimental and theoretical points of view in relation to joining ceramic and metal-ceramic systems by means of processes in the presence of a liquid phase (brazing, TLPB etc.). It is shown that wetting and the formation of interfacial dissolution regions are the results of the competition between different phenomena: dissolution of the ceramic in the liquid phase, reaction and formation of new phases at the solid-liquid interface, and drop spreading along the substrate surface. We emphasize the role of phase diagrams to support both the design of the experiments and the choice of active alloying elements, and to interpret the evolution of the system in relation to temperature and composition. In this respect, the sessile-drop technique has been shown to be helpful in assessing critical points of newly calculated phase diagrams. These studies are essential for the design of joining processes, for the creation of composite materials, and are of a particular relevance when applied to UHTC materials.

  18. Phase diagram, chemical stability and physical properties of the solid-solution Ba{sub 4}Nb{sub 2-x}Ta{sub x}O{sub 9}

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dunstan, Matthew T., E-mail: m.dunstan@chem.usyd.edu.au; Southon, Peter D.; Kepert, Cameron J.

    Through the construction of the Ba{sub 4}Nb{sub 2-x}Ta{sub x}O{sub 9} phase diagram, it was discovered that the unique high-temperature {gamma} phase is a thermodynamic intermediate between the low-temperature {alpha} phase (Sr{sub 4}Ru{sub 2}O{sub 9}-type) and a 6H-perovskite. Refined site occupancies for the {gamma} phase across the Ba{sub 4}Nb{sub 2-x}Ta{sub x}O{sub 9} solid-solution indicate that Nb preferentially occupies the tetrahedral sites over the octahedral sites in the structure. When annealed in a CO{sub 2}-rich atmosphere, all of the phases studied absorb large amounts of CO{sub 2} at high temperatures between {approx}700 and 1300 K. In situ controlled-atmosphere diffraction studies show thatmore » this behaviour is linked to the formation of BaCO{sub 3} on the surface of the material, accompanied by a Ba{sub 5}(Nb,Ta){sub 4}O{sub 15} impurity phase. In situ diffraction in humid atmospheres also confirms that these materials hydrate below {approx}1273K, and that this plays a critical role in the various reconstructive phase transitions as well as giving rise to proton conduction. - Graphical abstract: Thermodynamic phase diagram of Ba{sub 4}Nb{sub 2-x}Ta{sub x}O{sub 9}. Highlights: > {gamma}-Ba{sub 4}Nb{sub 2}O{sub 9} phase is a structural intermediate between the {alpha} and 6H-perovskite phases. > Ba{sub 4}Nb{sub 2}O{sub 9} and Ba{sub 4}Ta{sub 2}O{sub 9} decompose at high temperatures in the presence of CO{sub 2}. > These materials all absorb between 5% and 6% of CO{sub 2} by mass between {approx}800 and 1200 K.« less

  19. Characterization of SrCo1.5Ti1.5Fe9O19 hexagonal ferrite synthesized by sol-gel combustion and solid state route

    NASA Astrophysics Data System (ADS)

    Vinaykumar, R.; Mazumder, R.; Bera, J.

    2017-05-01

    Co-Ti co-substituted SrM hexagonal ferrite (SrCo1.5Ti1.5Fe9O19) was synthesized by sol-gel combustion and solid state route. The effects of sources of TiO2 raw materials; titanium tetra-isopropoxide (TTIP) and titanyl nitrate (TN) on the phase formation behavior and properties of the ferrite were studied. The thermal decomposition behavior of the gel was studied using TG-DSC. The phase formation behavior of the ferrite was studied by using X-ray powder diffraction and FTIR analysis. Phase formation was comparatively easier in the TN-based sol-gel process. The morphology of powder and sintered ferrite was investigated using scanning electron microscope. Magnetic properties like magnetization, coercivity, permeability, tan δμ and dielectric properties were investigated. The ferrite synthesized by sol-gel based chemical route showed higher saturation magnetization, permeability and permittivity compared to the ferrite synthesized by solid state route.

  20. Platform construction and extraction mechanism study of magnetic mixed hemimicelles solid-phase extraction

    NASA Astrophysics Data System (ADS)

    Xiao, Deli; Zhang, Chan; He, Jia; Zeng, Rong; Chen, Rong; He, Hua

    2016-12-01

    Simple, accurate and high-throughput pretreatment method would facilitate large-scale studies of trace analysis in complex samples. Magnetic mixed hemimicelles solid-phase extraction has the power to become a key pretreatment method in biological, environmental and clinical research. However, lacking of experimental predictability and unsharpness of extraction mechanism limit the development of this promising method. Herein, this work tries to establish theoretical-based experimental designs for extraction of trace analytes from complex samples using magnetic mixed hemimicelles solid-phase extraction. We selected three categories and six sub-types of compounds for systematic comparative study of extraction mechanism, and comprehensively illustrated the roles of different force (hydrophobic interaction, π-π stacking interactions, hydrogen-bonding interaction, electrostatic interaction) for the first time. What’s more, the application guidelines for supporting materials, surfactants and sample matrix were also summarized. The extraction mechanism and platform established in the study render its future promising for foreseeable and efficient pretreatment under theoretical based experimental design for trace analytes from environmental, biological and clinical samples.

  1. Optical Limiting by Index-Matched Phase-Segregated Mixtures

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Exarhos, Gregory J.; Ferris, Kim F.; Manijeh Razeghi, Gail J. Brown

    The nonlinear optical response for index-matched, non-absorbing immiscible phases (liquid-solid, liquid-liquid, solid-solid) has been determined by means of open aperture z-scan measurements. In mixtures where one constituent shows a relatively high optical nonlinearity, rapid and reversible transformation to a light-scattering state is observed under conditions where a critical incident light fluence is exceeded. This passive broadband response is induced by a transient change in the dispersive part of the refractive index, and is based upon the Christiansen-Shelyubskii filter that at one time was used as a means to monitor the temperature of glass melts. Modeling studies are used to simulatemore » scattering intensities in such textured composites as a function of composition, microstructure, and constituent optical properties. Results provide a rational approach to the selection of materials for use in these limiters. Challenges to preparing dispersed phase mixtures and their response to 532 nm nanosecond pulsed laser irradiation are described.« less

  2. Materials and other needs for advanced phase change memory (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Sosa, Norma E.

    2015-09-01

    Phase change memory (PCM), with its long history, may now hold its brightest promise to date. This bright future is being fueled by the "push" from big data. PCM is a non-volatile memory technology used to create solid-state random access memory devices that operate based the resistance properties of materials. Employing the electrical resistance differences-as opposed to differences in charge stored-between the amorphous and crystalline phases of the material, PCM can store bits, namely one's and zero's. Indeed, owing to the method of storage, PCM can in fact be designed to hold multiple bits thus leading to a high-density technology twice the storage density and less than half the cost of DRAM, the main kind found in typical personal computers. It has been long known that PCM can fill a need gap that spans 3 decades in performance from DRAM to solid state drive (NAND Flash). Furthermore, PCM devices can lead to performance and reliability improvements essential to enabling significant steps forward to supporting big data centric computing. This talk will focus on the science and challenges of aggressive scaling to realize the density needed, how this scaling challenge is intertwined with materials needs for endurance into the giga-cycles, and the associated forefront research aiming to realizing multi-level functionality into these nanoscale programmable resistor devices.

  3. [Simultaneous determination of ten benzotriazole ultraviolet stabilizers in food contact plastic materials by solid phase extraction and ultra performance liquid chromatography with tandem mass spectrometry].

    PubMed

    Gou, Xinlei; Zhao, Xinying; Chi, Haitao; Gao, Xia; Zhou, Mingqiang; Liu, Weili

    2015-06-01

    A sensitive method was developed for the simultaneous determination of ten benzotriazole ultraviolet stabilizers in food contact plastic materials by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The sample was extracted by methanol-dichloromethane, and purified by a C18 solid-phase extraction (SPE) column. The separation was performed by using water containing 0. 1% (v/v) formic acid and methanol as the mobile phases with gradient elution at a flow rate of 0. 3 mL/min. The electrospray ionization (ESI) source in positive ion mode was used for the analysis of the ten benzotriazole ultraviolet stabilizers in multiple reaction monitoring (MRM) mode. The results showed that the standard curves were obtained with good correlation coefficients (r2 > 0.996) in their linear concentration ranges. The limits of detection (LODs, S/N = 3) for the ten benzotriazole ultraviolet stabilizers were in the range of 0.6-1.6 µg/kg. The mean recoveries for the ten benzotriazole ultraviolet stabilizers at three spiked levels (low, medium and high) were 75.2%-85.3% with relative standard deviations of 1.0%-5.7%. Ten kinds of food contact plastic materials were tested, and 2,2'-methylenebis (6-(benzotriazol-2-yl)-4-tert-octylphenol) (UV-360) was found in a sample of polyethylene (PE) material. The method is accurate, simple, rapid and feasible for the simultaneous determination of benzotriazole ultraviolet stabilizers in food plastic materials.

  4. Advanced functional materials in solid phase extraction for ICP-MS determination of trace elements and their species - A review.

    PubMed

    He, Man; Huang, Lijin; Zhao, Bingshan; Chen, Beibei; Hu, Bin

    2017-06-22

    For the determination of trace elements and their species in various real samples by inductively coupled plasma mass spectrometry (ICP-MS), solid phase extraction (SPE) is a commonly used sample pretreatment technique to remove complex matrix, pre-concentrate target analytes and make the samples suitable for subsequent sample introduction and measurements. The sensitivity, selectivity/anti-interference ability, sample throughput and application potential of the methodology of SPE-ICP-MS are greatly dependent on SPE adsorbents. This article presents a general overview of the use of advanced functional materials (AFMs) in SPE for ICP-MS determination of trace elements and their species in the past decade. Herein the AFMs refer to the materials featuring with high adsorption capacity, good selectivity, fast adsorption/desorption dynamics and satisfying special requirements in real sample analysis, including nanometer-sized materials, porous materials, ion imprinting polymers, restricted access materials and magnetic materials. Carbon/silica/metal/metal oxide nanometer-sized adsorbents with high surface area and plenty of adsorption sites exhibit high adsorption capacity, and porous adsorbents would provide more adsorption sites and faster adsorption dynamics. The selectivity of the materials for target elements/species can be improved by using physical/chemical modification, ion imprinting and restricted accessed technique. Magnetic adsorbents in conventional batch operation offer unique magnetic response and high surface area-volume ratio which provide a very easy phase separation, greater extraction capacity and efficiency over conventional adsorbents, and chip-based magnetic SPE provides a versatile platform for special requirement (e.g. cell analysis). The performance of these adsorbents for the determination of trace elements and their species in different matrices by ICP-MS is discussed in detail, along with perspectives and possible challenges in the future development. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Application of computational methods to the design and characterisation of porous molecular materials.

    PubMed

    Evans, Jack D; Jelfs, Kim E; Day, Graeme M; Doonan, Christian J

    2017-06-06

    Composed from discrete units, porous molecular materials (PMMs) possess unique properties not observed for conventional, extended, solids, such as solution processibility and permanent porosity in the liquid phase. However, identifying the origin of porosity is not a trivial process, especially for amorphous or liquid phases. Furthermore, the assembly of molecular components is typically governed by a subtle balance of weak intermolecular forces that makes structure prediction challenging. Accordingly, in this review we canvass the crucial role of molecular simulations in the characterisation and design of PMMs. We will outline strategies for modelling porosity in crystalline, amorphous and liquid phases and also describe the state-of-the-art methods used for high-throughput screening of large datasets to identify materials that exhibit novel performance characteristics.

  6. Structural Characterization of AgGaS2-type Photocatalysts for Hydrogen Production from Water Under Visible Light

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Choi, Sun Hee; Shin, Namsoo; Jang, Jum Suk

    Bulky AgGaS2 was synthesized as a p-type semiconductor photocatalyst by a conventional solid state reaction under N2 flow for hydrogen production under visible light. To remove the impurity phase involved in the synthesized material and improve its crystallinity, the material was treated at various temperatures of 873-1123 K under H2S flow. Impurity phases were identified as {beta}-Ga2O3 and Ag9GaS6 with Rietveld analysis of XRD, and the local coordination structure around gallium atom in AgGaS2 was investigated by EXAFS. As the H2S-treatment temperature increased, the contribution from impurity phase was diminished. When the temperature reached 1123 K, the impurity phases weremore » completely removed and the material showed the highest photocatalytic activity.« less

  7. Importance of material and friction characterisation for FE-aided process design of hybrid bevel gears

    NASA Astrophysics Data System (ADS)

    Behrens, B.-A.; Bouguecha, A.; Bonk, C.; Matthias, T.

    2017-10-01

    Solid-forming components are often used in areas where they are subjected to very high loads. For most solid components locally divergent and sometimes contradictory requirements exist. Despite these contradictory requirements, almost exclusively monomaterials are nowadays used for the production of solid components. These components often reach their material-specific limits because of increasing demands on the products. Thus a significant increase in product quality and profitability would result from combining different materials in order to create tailored properties. In the Collaborative Research Center (CRC) 1153 "Tailored Forming" at the Leibniz Universität Hannover, this topic is investigated. The primary objective of the CRC 1153 is to develop and investigate new tailored manufacturing processes to produce reliable hybrid solid semi-finished components. In contrast to existing production processes of hybrid solid components, semi-finished workpieces in the CRC 1153 are joined before the forming phase. Thus, it will be possible to produce complex and highly stressable solid components made of different metals, which cannot be produced yet with the current used technologies. In this work the material and friction characteristics are investigated and the forming tool for the production of hybrid bevel gears made of different steel alloys (C22 and 41Cr4) is designed by numerical simulations. For this purpose, flow curves of both materials are determined by means of upsetting tests at process-related forming temperatures and strain rates. The temperature range for the forming process of the semi-finished product is determined by comparing the respective flow curves regarding similar flow stresses. Furthermore, the friction between the tool and the joining materials is investigated by means of ring upsetting tests at a process-relevant temperature. Finally, a stress analysis of the forming tools is carried out.

  8. Three-dimensional mapping of crystalline ceramic waste form materials

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cocco, Alex P.; DeGostin, Matthew B.; Wrubel, Jacob A.

    Here, we demonstrate the use of synchrotron-based, transmission X-ray microscopy (TXM) and scanning electron microscopy to image the 3-D morphologies and spatial distributions of Ga-doped phases within model, single- and two-phase waste form material systems. Gallium doping levels consistent with those commonly used for nuclear waste immobilization (e.g., Ba 1.04Cs 0.24Ga 2.32Ti 5.68O 16) could be readily imaged. This analysis suggests that a minority phase with different stoichiometry/composition from the primary hollandite phase can be formed by the solid-state ceramic processing route with varying morphology (globular vs. cylindrical) as a function of Cs content. Our results represent a crucial stepmore » in developing the tools necessary to gain an improved understanding of the microstructural and chemical properties of waste form materials that influence their resistance to aqueous corrosion. This understanding will aid in the future design of higher durability waste form materials.« less

  9. Three-dimensional mapping of crystalline ceramic waste form materials

    DOE PAGES

    Cocco, Alex P.; DeGostin, Matthew B.; Wrubel, Jacob A.; ...

    2017-04-21

    Here, we demonstrate the use of synchrotron-based, transmission X-ray microscopy (TXM) and scanning electron microscopy to image the 3-D morphologies and spatial distributions of Ga-doped phases within model, single- and two-phase waste form material systems. Gallium doping levels consistent with those commonly used for nuclear waste immobilization (e.g., Ba 1.04Cs 0.24Ga 2.32Ti 5.68O 16) could be readily imaged. This analysis suggests that a minority phase with different stoichiometry/composition from the primary hollandite phase can be formed by the solid-state ceramic processing route with varying morphology (globular vs. cylindrical) as a function of Cs content. Our results represent a crucial stepmore » in developing the tools necessary to gain an improved understanding of the microstructural and chemical properties of waste form materials that influence their resistance to aqueous corrosion. This understanding will aid in the future design of higher durability waste form materials.« less

  10. Effect of synthesis methods on the Ca{sub 3}Co{sub 4}O{sub 9} thermoelectric ceramic performances

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sotelo, A.; Rasekh, Sh.; Torres, M.A.

    2015-01-15

    Three different synthesis methods producing nanometric grain sizes, coprecipitation with ammonium carbonate, oxalic acid, and by attrition milling have been studied to produce Ca{sub 3}Co{sub 4}O{sub 9} ceramics and compared with the classical solid state route. These three processes have produced high reactive precursors and all the organic material and CaCO{sub 3}·have been decomposed in a single thermal treatment. Coprecipitation leads to pure Ca{sub 3}Co{sub 4}O{sub 9} phase, while attrition milling and classical solid state produce small amounts of Ca{sub 3}Co{sub 2}O{sub 6} secondary phase. Power factor values are similar for all three samples, being slightly lower for the onesmore » produced by attrition milling. These values are much higher than the obtained in samples prepared by the classical solid state method, used as reference. The maximum power factor values determined at 800 °C (∼0.43 mW/K{sup 2} m) are slightly higher than the best reported values obtained in textured ones which also show much higher density values. - Graphical abstract: Impressive raise of PF in Ca{sub 3}Co{sub 4}O{sub 9} thermoelectric materials obtained from nanometric grains. - Highlights: • Ca{sub 3}Co{sub 4}O{sub 9} has been produced by four different methods. • Precursors particle sizes influences on the final performances. • Coprecipitation methods produce single Ca{sub 3}Co{sub 4}O{sub 9} phase. • Power factor reaches values comparable to high density textured materials.« less

  11. The model of the long-range effect in solids: Evolution of structure, clusters of internal boundaries, and their statistical descriptors

    NASA Astrophysics Data System (ADS)

    Herega, Alexander; Sukhanov, Volodymyr; Vyrovoy, Valery

    2017-12-01

    It is known that the multifocal mechanism of genesis of structure of heterogeneous materials provokes intensive formation of internal boundaries. In the present papers, the dependence of the structure and properties of material on the characteristic size and shape, the number and size distribution, and the character of interaction of individual internal boundaries and their clusters is studied. The limitation on the applicability of the material damage coefficient is established; the effective information descriptor of internal boundaries is proposed. An idea of the effect of long-range interaction in irradiated solids on the realization of the second-order phase transition is introduced; a phenomenological percolation model of the effect is proposed.

  12. In Situ and Ex Situ TEM Study of Lithiation Behaviours of Porous Silicon Nanostructures

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shen, Chenfei; Ge, Mingyuan; Luo, Langli

    Here in this work, we study the lithiation behaviours of both porous silicon (Si) nanoparticles and porous Si nanowires by in situ and ex situ transmission electron microscopy (TEM) and compare them with solid Si nanoparticles and nanowires. The in situ TEM observation reveals that the critical fracture diameter of porous Si particles reaches up to 1.52 μm, which is much larger than the previously reported 150 nm for crystalline Si nanoparticles and 870 nm for amorphous Si nanoparticles. After full lithiation, solid Si nanoparticles and nanowires transform to crystalline Li 15Si 4 phase while porous Si nanoparticles and nanowiresmore » transform to amorphous Li xSi phase, which is due to the effect of domain size on the stability of Li 15Si 4 as revealed by the first-principle molecular dynamic simulation. Ex situ TEM characterization is conducted to further investigate the structural evolution of porous and solid Si nanoparticles during the cycling process, which confirms that the porous Si nanoparticles exhibit better capability to suppress pore evolution than solid Si nanoparticles. The investigation of structural evolution and phase transition of porous Si nanoparticles and nanowires during the lithiation process reveal that they are more desirable as lithium-ion battery anode materials than solid Si nanoparticles and nanowires.« less

  13. In Situ and Ex Situ TEM Study of Lithiation Behaviours of Porous Silicon Nanostructures

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shen, Chenfei; Ge, Mingyuan; Luo, Langli

    In this work, we study the lithiation behaviours of both porous silicon (Si) nanoparticles and porous Si nanowires by in situ and ex situ transmission electron microscopy (TEM) and compare them with solid Si nanoparticles and nanowires. The in situ TEM observation reveals that the critical fracture diameter of porous Si particles reaches up to 1.52 μm, which is much larger than the previously reported 150 nm for crystalline Si nanoparticles and 870 nm for amorphous Si nanoparticles. After full lithiation, solid Si nanoparticles and nanowires transform to crystalline Li15Si4 phase while porous Si nanoparticles and nanowires transform to amorphousmore » LixSi phase, which is due to the effect of domain size on the stability of Li15Si4 as revealed by the first-principle molecular dynamic simulation. Ex situ TEM characterization is conducted to further investigate the structural evolution of porous and solid Si nanoparticles during the cycling process, which confirms that the porous Si nanoparticles exhibit better capability to suppress pore evolution than solid Si nanoparticles. The investigation of structural evolution and phase transition of porous Si nanoparticles and nanowires during the lithiation process reveal that they are more desirable as lithium-ion battery anode materials than solid Si nanoparticles and nanowires.« less

  14. In Situ and Ex Situ TEM Study of Lithiation Behaviours of Porous Silicon Nanostructures

    NASA Astrophysics Data System (ADS)

    Shen, Chenfei; Ge, Mingyuan; Luo, Langli; Fang, Xin; Liu, Yihang; Zhang, Anyi; Rong, Jiepeng; Wang, Chongmin; Zhou, Chongwu

    2016-08-01

    In this work, we study the lithiation behaviours of both porous silicon (Si) nanoparticles and porous Si nanowires by in situ and ex situ transmission electron microscopy (TEM) and compare them with solid Si nanoparticles and nanowires. The in situ TEM observation reveals that the critical fracture diameter of porous Si particles reaches up to 1.52 μm, which is much larger than the previously reported 150 nm for crystalline Si nanoparticles and 870 nm for amorphous Si nanoparticles. After full lithiation, solid Si nanoparticles and nanowires transform to crystalline Li15Si4 phase while porous Si nanoparticles and nanowires transform to amorphous LixSi phase, which is due to the effect of domain size on the stability of Li15Si4 as revealed by the first-principle molecular dynamic simulation. Ex situ TEM characterization is conducted to further investigate the structural evolution of porous and solid Si nanoparticles during the cycling process, which confirms that the porous Si nanoparticles exhibit better capability to suppress pore evolution than solid Si nanoparticles. The investigation of structural evolution and phase transition of porous Si nanoparticles and nanowires during the lithiation process reveal that they are more desirable as lithium-ion battery anode materials than solid Si nanoparticles and nanowires.

  15. In Situ and Ex Situ TEM Study of Lithiation Behaviours of Porous Silicon Nanostructures

    PubMed Central

    Shen, Chenfei; Ge, Mingyuan; Luo, Langli; Fang, Xin; Liu, Yihang; Zhang, Anyi; Rong, Jiepeng; Wang, Chongmin; Zhou, Chongwu

    2016-01-01

    In this work, we study the lithiation behaviours of both porous silicon (Si) nanoparticles and porous Si nanowires by in situ and ex situ transmission electron microscopy (TEM) and compare them with solid Si nanoparticles and nanowires. The in situ TEM observation reveals that the critical fracture diameter of porous Si particles reaches up to 1.52 μm, which is much larger than the previously reported 150 nm for crystalline Si nanoparticles and 870 nm for amorphous Si nanoparticles. After full lithiation, solid Si nanoparticles and nanowires transform to crystalline Li15Si4 phase while porous Si nanoparticles and nanowires transform to amorphous LixSi phase, which is due to the effect of domain size on the stability of Li15Si4 as revealed by the first-principle molecular dynamic simulation. Ex situ TEM characterization is conducted to further investigate the structural evolution of porous and solid Si nanoparticles during the cycling process, which confirms that the porous Si nanoparticles exhibit better capability to suppress pore evolution than solid Si nanoparticles. The investigation of structural evolution and phase transition of porous Si nanoparticles and nanowires during the lithiation process reveal that they are more desirable as lithium-ion battery anode materials than solid Si nanoparticles and nanowires. PMID:27571919

  16. In Situ and Ex Situ TEM Study of Lithiation Behaviours of Porous Silicon Nanostructures

    DOE PAGES

    Shen, Chenfei; Ge, Mingyuan; Luo, Langli; ...

    2016-08-30

    Here in this work, we study the lithiation behaviours of both porous silicon (Si) nanoparticles and porous Si nanowires by in situ and ex situ transmission electron microscopy (TEM) and compare them with solid Si nanoparticles and nanowires. The in situ TEM observation reveals that the critical fracture diameter of porous Si particles reaches up to 1.52 μm, which is much larger than the previously reported 150 nm for crystalline Si nanoparticles and 870 nm for amorphous Si nanoparticles. After full lithiation, solid Si nanoparticles and nanowires transform to crystalline Li 15Si 4 phase while porous Si nanoparticles and nanowiresmore » transform to amorphous Li xSi phase, which is due to the effect of domain size on the stability of Li 15Si 4 as revealed by the first-principle molecular dynamic simulation. Ex situ TEM characterization is conducted to further investigate the structural evolution of porous and solid Si nanoparticles during the cycling process, which confirms that the porous Si nanoparticles exhibit better capability to suppress pore evolution than solid Si nanoparticles. The investigation of structural evolution and phase transition of porous Si nanoparticles and nanowires during the lithiation process reveal that they are more desirable as lithium-ion battery anode materials than solid Si nanoparticles and nanowires.« less

  17. Influence of defect distribution on the thermoelectric properties of FeNbSb based materials.

    PubMed

    Guo, Shuping; Yang, Kaishuai; Zeng, Zhi; Zhang, Yongsheng

    2018-05-21

    Doping and alloying are important methodologies to improve the thermoelectric performance of FeNbSb based materials. To fully understand the influence of point defects on the thermoelectric properties, we have used density functional calculations in combination with the cluster expansion and Monte Carlo methods to examine the defect distribution behaviors in the mesoscopic FeNb1-xVxSb and FeNb1-xTixSb systems. We find that V and Ti exhibit different distribution behaviors in FeNbSb at low temperature: forming the FeNbSb-FeVSb phase separations in the FeNb1-xVxSb system but two thermodynamically stable phases in FeNb1-xTixSb. Based on the calculated effective mass and band degeneracy, it seems the doping concentration of V or Ti in FeNbSb has little effect on the electrical properties, except for one of the theoretically predicted stable Ti phases (Fe6Nb5Ti1Sb6). Thus, an essential methodology to improve the thermoelectric performance of FeNbSb should rely on phonon scattering to decrease the thermal conductivity. According to the theoretically determined phase diagrams of Fe(Nb,V)Sb and Fe(Nb,Ti)Sb, we propose the (composition, temperature) conditions for the experimental synthesis to improve the thermoelectric performance of FeNbSb based materials: lowering the experimental preparation temperature to around the phase boundary to form a mixture of the solid solution and phase separation. The point defects in the solid solution effectively scatter the short-wavelength phonons and the (coherent or incoherent) interfaces introduced by the phase separation can additionally scatter the middle-wavelength phonons to further decrease the thermal conductivity. Moreover, the induced interfaces could enhance the Seebeck coefficient as well, through the energy filtering effect. Our results give insight into the understanding of the impact of the defect distribution on the thermoelectric performance of materials and strengthen the connection between theoretical predictions and experimental measurements.

  18. Two-Phase Solid/Fluid Simulation of Dense Granular Flows With Dilatancy Effects

    NASA Astrophysics Data System (ADS)

    Mangeney, A.; Bouchut, F.; Fernández-Nieto, E. D.; Kone, E. H.; Narbona-Reina, G.

    2016-12-01

    Describing grain/fluid interaction in debris flows models is still an open and challenging issue with key impact on hazard assessment [1]. We present here a two-phase two-thin-layer model for fluidized debris flows that takes into account dilatancy effects. It describes the velocity of both the solid and the fluid phases, the compression/ dilatation of the granular media and its interaction with the pore fluid pressure [2]. The model is derived from a 3D two-phase model proposed by Jackson [3] and the mixture equations are closed by a weak compressibility relation. This relation implies that the occurrence of dilation or contraction of the granular material in the model depends on whether the solid volume fraction is respectively higher or lower than a critical value. When dilation occurs, the fluid is sucked into the granular material, the pore pressure decreases and the friction force on the granular phase increases. On the contrary, in the case of contraction, the fluid is expelled from the mixture, the pore pressure increases and the friction force diminishes. To account for this transfer of fluid into and out of the mixture, a two-layer model is proposed with a fluid or a solid layer on top of the two-phase mixture layer. Mass and momentum conservation are satisfied for the two phases, and mass and momentum are transferred between the two layers. A thin-layer approximation is used to derive average equations. Special attention is paid to the drag friction terms that are responsible for the transfer of momentum between the two phases and for the appearance of an excess pore pressure with respect to the hydrostatic pressure. By comparing quantitatively the results of simulation and laboratory experiments on submerged granular flows, we show that our model contains the basic ingredients making it possible to reproduce the interaction between the granular and fluid phases through the change in pore fluid pressure. In particular, we analyse the different time scales in the model and their role in granular/fluid flow dynamics. References[1] R. Delannay, A. Valance, A. Mangeney, O. Roche, P. Richard, J. Phys. D: Appl. Phys., in press (2016). [2] F. Bouchut, E. D. Fernández-Nieto, A. Mangeney, G. Narbona-Reina, J. Fluid Mech., 801, 166-221 (2016). [3] R. Jackson, Cambridges Monographs on Mechanics (2000).

  19. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Iwamoto, Y.; Shin, S.G.; Matsubara, H.

    The grain growth behavior of ceramic materials under the existence of a liquid phase was investigated for Si{sub 3}N{sub 4}-Y{sub 2}O{sub 3}-SiO{sub 2}, TiC-Ni, and WC-Co systems. The kinetics of grain growth behavior of these systems closely fitted to the cubic relation of d{sup 3} - d{sub 0}{sup 3} = Kt. The growth rate of {beta}-Si{sub 3}N{sub 4} grain was approximately one order of magnitude larger in length direction than that in width direction. The growth rate slightly increased with increasing liquid phase content in both these directions of the {beta}-Si{sub 3}N{sub 4} grain. TiC-Ni and WC-Co cermets had amore » peak in growth rate at a certain liquid phase content. The rate constant values of these systems were much smaller by a factor of 10{sup 3}{approximately}10{sup 5} compared to the theoretical values expected from the diffusion-controlled growth model. The experimental growth rates tended to decrease with increasing contiguity of the solid phase. The grain growth behavior of these systems could be explained by the mechanism resulting from the existence of contiguous boundaries of solid phase, which suppressed the movement of solid/liquid interfaces during liquid phase sintering.« less

  20. Tested Demonstrations.

    ERIC Educational Resources Information Center

    Gilbert, George L., Ed.

    1983-01-01

    Describes a lecture demonstration of a solid state phase transition using a thermodynamic material which changes state at room temperature. Also describes a demonstration on kinetics using a "Big Bang" (trade mark) calcium carbide cannon. Indicates that the cannon is safe to use. (JN)

  1. Solid-solid phase transformation via internal stress-induced virtual melting, significantly below the melting temperature. Application to HMX energetic crystal.

    PubMed

    Levitas, Valery I; Henson, Bryan F; Smilowitz, Laura B; Asay, Blaine W

    2006-05-25

    We theoretically predict a new phenomenon, namely, that a solid-solid phase transformation (PT) with a large transformation strain can occur via internal stress-induced virtual melting along the interface at temperatures significantly (more than 100 K) below the melting temperature. We show that the energy of elastic stresses, induced by transformation strain, increases the driving force for melting and reduces the melting temperature. Immediately after melting, stresses relax and the unstable melt solidifies. Fast solidification in a thin layer leads to nanoscale cracking which does not affect the thermodynamics or kinetics of the solid-solid transformation. Thus, virtual melting represents a new mechanism of solid-solid PT, stress relaxation, and loss of coherence at a moving solid-solid interface. It also removes the athermal interface friction and deletes the thermomechanical memory of preceding cycles of the direct-reverse transformation. It is also found that nonhydrostatic compressive internal stresses promote melting in contrast to hydrostatic pressure. Sixteen theoretical predictions are in qualitative and quantitative agreement with experiments conducted on the PTs in the energetic crystal HMX. In particular, (a) the energy of internal stresses is sufficient to reduce the melting temperature from 551 to 430 K for the delta phase during the beta --> delta PT and from 520 to 400 K for the beta phase during the delta --> beta PT; (b) predicted activation energies for direct and reverse PTs coincide with corresponding melting energies of the beta and delta phases and with the experimental values; (c) the temperature dependence of the rate constant is determined by the heat of fusion, for both direct and reverse PTs; results b and c are obtained both for overall kinetics and for interface propagation; (d) considerable nanocracking, homogeneously distributed in the transformed material, accompanies the PT, as predicted by theory; (e) the nanocracking does not change the PT thermodynamics or kinetics appreciably for the first and the second PT beta <--> delta cycles, as predicted by theory; (f) beta <--> delta PTs start at a very small driving force (in contrast to all known solid-solid transformations with large transformation strain), that is, elastic energy and athermal interface friction must be negligible; (g) beta --> alpha and alpha --> beta PTs, which are thermodynamically possible in the temperature range 382.4 < theta < 430 K and below 382.4 K, respectively, do not occur.

  2. Chemical hydrogen storage material property guidelines for automotive applications

    NASA Astrophysics Data System (ADS)

    Semelsberger, Troy A.; Brooks, Kriston P.

    2015-04-01

    Chemical hydrogen storage is the sought after hydrogen storage media for automotive applications because of the expected low pressure operation (<20 atm), moderate temperature operation (<200 °C), system gravimetric capacities (>0.05 kg H2/kgsystem), and system volumetric capacities (>0.05 kg H2/Lsystem). Currently, the primary shortcomings of chemical hydrogen storage are regeneration efficiency, fuel cost and fuel phase (i.e., solid or slurry phase). Understanding the required material properties to meet the DOE Technical Targets for Onboard Hydrogen Storage Systems is a critical knowledge gap in the hydrogen storage research community. This study presents a set of fluid-phase chemical hydrogen storage material property guidelines for automotive applications meeting the 2017 DOE technical targets. Viable material properties were determined using a boiler-plate automotive system design. The fluid-phase chemical hydrogen storage media considered in this study were neat liquids, solutions, and non-settling homogeneous slurries. Material properties examined include kinetics, heats of reaction, fuel-cell impurities, gravimetric and volumetric hydrogen storage capacities, and regeneration efficiency. The material properties, although not exhaustive, are an essential first step in identifying viable chemical hydrogen storage material properties-and most important, their implications on system mass, system volume and system performance.

  3. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Van Valin, R.; Morse, J.W.

    The operation of an OTEC plant will result in the mixing of large volumes of seawater from different depths within the ocean. Because suspended particulate material is intimately involved in marine food webs and transition metals, such as copper, can have toxic effects, it is important to develop a sound methodology for characterizing and quantifying transition metal behavior associated with the solid material. The characterization of solid-phase-associated transition metals in the marine environment has largely been directed at marine sediments. These studies have generally indicated that it is not possible to uniquely identify the solid phases or chemical speciation ofmore » a given metal. There are many reasons for this difficulty, but the probable major analytical problems arise from the fact that many of the transition metals of interest are present only in trace concentrations as adsorbed species on amorphous oxides or as coprecipitates. In one approach transition metals are classified according to how easily they are solubilized when exposed to different types of chemical attack, as defined in chemical extraction schemes. In this study, several of the most widely accepted extraction techniques were compared for many of the most commonly measured transition metals to a variety of marine sediments. Based on the results of this study, the sequential extraction scheme of Tessler et al. (1979) is the recommended method for the characterization of solid-phase associated transition metals. An increase of the reducing agent concentration in the intermediate step and temperature decrease with an additional HCl digestion in the residual step are recommended as improvements, based on the results of the individual extraction method studies.« less

  4. Solid State Ionic Materials - Proceedings of the 4th Asian Conference on Solid State Ionics

    NASA Astrophysics Data System (ADS)

    Chowdari, B. V. R.; Yahaya, M.; Talib, I. A.; Salleh, M. M.

    1994-07-01

    The Table of Contents for the full book PDF is as follows: * Preface * I. INVITED PAPERS * Diffusion of Cations and Anions in Solid Electrolytes * Silver Ion Conductors in the Crystalline State * NMR Studies of Superionic Conductors * Hall Effect and Thermoelectric Power in High Tc Hg-Ba-Ca-Cu-O Ceramics * Solid Electrolyte Materials Prepared by Sol-Gel Chemistry * Preparation of Proton-Conducting Gel Films and their Application to Electrochromic Devices * Thin Film Fuel Cells * Zirconia based Solid Oxide Ion Conductors in Solid Oxide Fuel Cells * The Influence of Anion Substitution on Some Phosphate-based Ion Conducting Glasses * Lithium Intercalation in Carbon Electrodes and its Relevance in Rocking Chair Batteries * Chemical Sensors using Proton Conducting Ceramics * NMR/NQR Studies of Y-Ba-Cu-O Superconductors * Silver Molybdate Glasses and Battery Systems * New Highly Conducting Polymer Ionics and their Application in Electrochemical Devices * Study of Li Electrokinetics on Oligomeric Electrolytes using Microelectrodes * Calculation of Conductivity for Mixed-Phase Electrolytes PEO-MX-Immiscible Additive by Means of Effective Medium Theory * II. CONTRIBUTED PAPERS * Phase Relationship and Electrical Conductivity of Sr-V-O System with Vanadium Suboxide * Amorphous Li+ Ionic Conductors in Li2SO4-Li2O-P2O5 System * Fast Ion Transport in KCl-Al2O3 Composites * The Effect of the Second Phase Precipitation on the Ionic Conductivity of Zr0.85Mg0.15O1.85 * Conductivity Measurements and Phase Relationships in CaCl2-CaHCl Solid Electrolyte * Relationships Between Crystal Structure and Sodium Ion Conductivity in Na7Fe4(AsO4)6 and Na3Al2(AsO4)3 * Electrical Conductivity and Solubility Limit of Ti4+ Ion in Na1+x TiyZr2-ySixP3-xO12 System * Study on Sodium Fast Ion Conductors of Na1+3xAlxTi2-xSi2xP3-2xO12 System * Influences of Zirconia on the Properties of β''-Alumina Ceramics * Decay of Luminescence from Cr3+ Ions in β-Alumina * Lithium Ion Conductivity in the Li4XO4-Li2SO4 (X=Si, Ge, Ti) Systems * A DSC and Conductivity Study of the Influence of Cesium Ion on the Beta-Alpha Transition in Silver Iodide * Phase Diagrams, Stoichiometries and Properties of Bi4V2O11:M2+ Solid Electrolytes * Physical Properties of Electrodeposited Silver Chromotungstate * Pseudopotential Study of Bonding in the Superionic Material AgI: The Effect of Statistical Distribution of Mobile Ions * Cubic Phase Dominant Region in Submicron BaTiO3 Particles * The Crystallization of CoZr Amorphous Alloys via Electrical Resistivity * Cation Ratio Related Properties of Synthetic Mg/Al Layered Double Hydroxide and it's Nanocomposite * DC Conductivity of Nano-Particles of Silver Iodide * Effect of Anomalous Diffusion on Quasielastic Scattering in Superionic Conductors * Computer Simulation Study of Conductivity Enhancement in Superionic-Insulator Composites * Dynamics of Superionic Silver and Copper Iodide Salt Melts * Influence of Dopant Salt AgI, Glass Modifier Ag2O and Glass Formers (SeO3 + MoO3) on Electrical Conductivity in Quaternary Glassy System * Fast Ion Conductivity in the Presence of Competitive Network Formers * Role of Alkali Ions in Borate Glasses * Inelastic Light Scattering in Cadmium Borate Glasses * Investigation on Transport Properties of Mixed Glass System 0.75 [0.75AgI:0.25AgCl]. 0.25[Ag2O:CrO3] * Conduction Mechanism in Lithium Tellurite Glasses * Optimized Silver Tungstoarsenate Glass Electrolyte * Stabilized Superfine Zirconia Powder Prepared by Sol-Gel Process * Study of New PAN-based Electrolytes * Electrical and Thermal Characterization of PVA based Polymer Electrolytes * Conductive Electroactive Polymers: Versatile Solid State Ionic Materials * The Role of Ag2O Addition on the Superconducting Properties of Y-124 Compound * Absorption Spectra Studies of the C60 Films on Transition Metal Film Substrates * Effect of Alumina Dispersal on the Conductivity and Crystallite Size of Polymer Electrolyte * New Mixed Galss-Polymer Solid Electrolytes * The Sputtered La0.5Sr0.5MnO3-Yttria Stabilized Zirconia Composite Electrode in Solid Oxide Fuel Cells * A Solid Electrochemical Ferro Sensor for Molten Matte * SnO2-based Sensor for H2S Monitoring-Electrical Conductivity Measurements and Device Testing * Humidity Sensor using Potassium Tungsten Bronze Synthesized from Peroxo-Polytungstic Acid * Study on Li/LiClO4/V6O13 Test Cells * Fabrication and Characterisation of Some Solid Electrolyte Cells Containing CuI and Silver Oxysalts * Solid State Battery of Proton Conducting Sodium Thiosulphate Pentahydrate * Low Temperature Synthesis of LiMn2O4 for Secondary Lithium Batteries * Effect of Different Cathode Active Materials on Battery Performance with Silver Molybdate Electrolyte Partially Substituted with Zinc Oxide * Fabrication and Characterization of Electrochemical Cells based on Silver Molybdoarsenate and Silver Tungstoarsenate Glass Electrolytes * Lorentz Force Dependence of Dissipation in a Granular Superconductor * Late Entry (Invited paper) * Simultaneous Voltammetry and Spectroscopy of Polyaniline in Propylene Carbonate * Author Index * Tentative List of Participants

  5. Municipal solid waste composition determination supporting the integrated solid waste management system in the island of Crete.

    PubMed

    Gidarakos, E; Havas, G; Ntzamilis, P

    2006-01-01

    A one-year survey was conducted in the greater region of Crete (located at the lower region of the Aegean Sea) for the purpose of identifying waste composition (including chemical and physical characterization), as well as any seasonal variation. The investigation was carried out repeatedly at seven landfills and one transfer station in Crete, in four phases. Each sampling phase corresponded to a season (autumn, winter, spring, summer). ASTM D5231-92(2003) standard method and RCRA Waste Sampling Draft Technical Guidance were used. Hand sorting was used for classifying the collected wastes into the following categories: plastics, paper, metals, aluminium, leather-wood-textiles-rubbers, organic wastes, non-combustibles and miscellaneous. Further analysis included proximate and ultimate analysis of combustible materials. Metals such as lead, cadmium and mercury were also investigated. The results show that there has been a significant decrease of organic wastes during the last decade due to the increase of packaging materials, as a result of a change in consumption patterns. Three main waste categories were determined: organic wastes, paper and plastics, which combined represent 76% of the total waste in Crete. Furthermore, a high fraction of glass and a seasonal variation of aluminium indicate a strong correlation of waste composition with certain human activities, such as tourism. There is also a variation between the municipal solid waste (MSW) composition in the region of Crete (2003-2004) and MSW composition suggested in the National Solid Waste Planning (2000) [National Solid Waste Planning, 2000. Completion and particularization of Common Ministerial Act 113944//1944/1997: National Solid Waste Planning, June 2000]. The results of this survey are to be utilized by the regional solid waste authorities in order to establish an integrated waste treatment site, capable of fulfilling the regional waste management demands.

  6. Flexibility transition and guest-driven reconstruction in a ferroelastic metal-organic framework†Electronic supplementary information (ESI) available: Atomic coordinates and lattice parameter data. CCDC 1016797. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c4ce01572jClick here for additional data file.

    PubMed

    Hunt, Sarah J; Cliffe, Matthew J; Hill, Joshua A; Cairns, Andrew B; Funnell, Nicholas P; Goodwin, Andrew L

    2015-01-14

    The metal-organic framework copper(i) tricyanomethanide, Cu(tcm), undergoes a ferroelastic transition on cooling below T f = 240 K. Thermal expansion measurements reveal an order-of-magnitude variation in framework flexibility across T f . The low-temperature phase α-Cu(tcm) exhibits colossal positive and negative thermal expansion that is the strongest ever reported for a framework material. On exposure to acetonitrile, Cu(tcm) undergoes a reconstructive solid-phase transition to acetonitrilocopper(i) tricyanomethanide. This transition can be reversed by heating under vacuum. Infrared spectroscopy measurements are sensitive to the phase change, suggesting that Cu(tcm) may find application in solid-phase acetonitrile sensing.

  7. Perspective: Toward "synthesis by design": Exploring atomic correlations during inorganic materials synthesis

    NASA Astrophysics Data System (ADS)

    Soderholm, L.; Mitchell, J. F.

    2016-05-01

    Synthesis of inorganic extended solids is a critical starting point from which real-world functional materials and their consequent technologies originate. However, unlike the rich mechanistic foundation of organic synthesis, with its underlying rules of assembly (e.g., functional groups and their reactivities), the synthesis of inorganic materials lacks an underpinning of such robust organizing principles. In the latter case, any such rules must account for the diversity of chemical species and bonding motifs inherent to inorganic materials and the potential impact of mass transport on kinetics, among other considerations. Without such assembly rules, there is less understanding, less predictive power, and ultimately less control of properties. Despite such hurdles, developing a mechanistic understanding for synthesis of inorganic extended solids would dramatically impact the range of new material discoveries and resulting new functionalities, warranting a broad call to explore what is possible. Here we discuss our recent approaches toward a mechanistic framework for the synthesis of bulk inorganic extended solids, in which either embryonic atomic correlations or fully developed phases in solutions or melts can be identified and tracked during product selection and crystallization. The approach hinges on the application of high-energy x-rays, with their penetrating power and large Q-range, to explore reaction pathways in situ. We illustrate this process using two examples: directed assembly of Zr clusters in aqueous solution and total phase awareness during crystallization from K-Cu-S melts. These examples provide a glimpse of what we see as a larger vision, in which large scale simulations, data-driven science, and in situ studies of atomic correlations combine to accelerate materials discovery and synthesis, based on the assembly of well-defined, prenucleated atomic correlations.

  8. Perspective: Toward “synthesis by design”: Exploring atomic correlations during inorganic materials synthesis

    DOE PAGES

    Soderholm, L.; Mitchell, J. F.

    2016-05-26

    Synthesis of inorganic extended solids is a critical starting point from which real-world functional materials and their consequent technologies originate. However, unlike the rich mechanistic foundation of organic synthesis, with its underlying rules of assembly (e.g., functional groups and their reactivities), the synthesis of inorganic materials lacks an underpinning of such robust organizing principles. In the latter case, any such rules must account for the diversity of chemical species and bonding motifs inherent to inorganic materials and the potential impact of mass transport on kinetics, among other considerations. Without such assembly rules, there is less understanding, less predictive power, andmore » ultimately less control of properties. Despite such hurdles, developing a mechanistic understanding for synthesis of inorganic extended solids would dramatically impact the range of new material discoveries and resulting new functionalities, warranting a broad call to explore what is possible. Here we discuss our recent approaches toward a mechanistic framework for the synthesis of bulk inorganic extended solids, in which either embryonic atomic correlations or fully developed phases in solutions or melts can be identified and tracked during product selection and crystallization. The approach hinges on the application of high-energy x-rays, with their penetrating power and large Q-range, to explore reaction pathways in situ. We illustrate this process using two examples: directed assembly of Zr clusters in aqueous solution and total phase awareness during crystallization from K–Cu–S melts. These examples provide a glimpse of what we see as a larger vision, in which large scale simulations, data-driven science, and in situ studies of atomic correlations combine to accelerate materials discovery and synthesis, based on the assembly of well-defined, prenucleated atomic correlations.« less

  9. Field Verification Program (Aquatic Disposal). Bioenergetic Effects of Black Rock Harbor Dredged Material on the Polychaete Nephtys incisa: A Field Verification.

    DTIC Science & Technology

    1988-03-01

    observed in the laboratory, and to determine the degree of correlation between the bioaccumulation of contaminants and bioenergetic responses...toxicity of liquid, suspended particulate, and solid phases; (c) estimating the potential contami- nant bioaccumulation ; and (d) describing the initial... bioaccumulation of dredged material contami- nants with biological responses from laboratory and field exposure to dredged material. However, this study

  10. The Cu-Li-Sn Phase Diagram: Isopleths, Liquidus Projection and Reaction Scheme

    PubMed Central

    Flandorfer, Hans

    2016-01-01

    The Cu-Li-Sn phase diagram was constructed based on XRD and DTA data of 60 different alloy compositions. Eight ternary phases and 14 binary solid phases form 44 invariant ternary reactions, which are illustrated by a Scheil-Schulz reaction scheme and a liquidus projection. Phase equilibria as a function of concentration and temperature are shown along nine isopleths. This report together with an earlier publication of our group provides for the first time comprehensive investigations of phase equilibria and respective phase diagrams. Most of the phase equilibria could be established based on our experimental results. Only in the Li-rich part where many binary and ternary compounds are present estimations had to be done which are all indicated by dashed lines. A stable ternary miscibility gap could be found which was predicted by modelling the liquid ternary phase in a recent work. The phase diagrams are a crucial input for material databases and thermodynamic optimizations regarding new anode materials for high-power Li-ion batteries. PMID:27788175

  11. Optical and Raman microspectroscopy of nitrogen and hydrogen mixtures at high pressures

    NASA Astrophysics Data System (ADS)

    Ciezak, Jennifer; Jenkins, T.; Hemley, R.

    2009-06-01

    Extended phases of molecular solids formed from simple molecules have led to polymeric materials under extreme conditions with advanced optical, mechanical and energetic properties. Although the existence of extended phases has been demonstrated in N2, CO and CO2, recovery of the materials to ambient conditions has posed considerable difficulty. Recent molecular dynamics simulations have predicted that the addition of hydrogen to nitrogen may increase the stability of the cubic-gauche nitrogen polymer and thereby offer the possibility of synthesis at lower pressures and temperatures. Here we present optical and Raman microspectroscopy measurements performed on nitrogen and hydrogen mixtures to 85 GPa. To pressures of 30 GPa, large deviations in the internal molecular stretching modes of the mixtures relative to those of the pure material reveal unusual phase behavior. After an unusual phase separation near 35 GPa, a phase assemblage of consisting of a phase rich in both nitrogen and hydrogen, a phase of relatively amorphous nitrogen and a mixture of the two is observed. Near this pressure, Raman bands attributed to the N-N single bonded stretch were observed.

  12. Mechanical Alloying of W-Mo-V-Cr-Ta High Entropy Alloys

    NASA Astrophysics Data System (ADS)

    Das, Sujit; Robi, P. S.

    2018-04-01

    Recent years have seen the emergence of high-entropy alloys (HEAs) consisting of five or more elements in equi-atomic or near equi-atomic ratios. These alloys in single phase solid solution exhibit exceptional mechanical properties viz., high strength at room and elevated temperatures, reasonable ductility and stable microstructure over a wide range of temperatures making it suitable for high temperature structural materials. In spite of the attractive properties, processing of these materials remains a challenge. Reports regarding fabrication and characterisation of a few refractory HEA systems are available. The processing of these alloys have been carried out by arc melting of small button sized materials. The present paper discusses the development of a novel refractory W-Mo-V-Cr-Ta HEA powder based on a new alloy design concept. The powder mixture was milled for time periods up to 64 hours. Single phase alloy powder having body centred cubic structure was processed by mechanical alloying. The milling characteristics and extent of alloying during the ball milling were characterized using X-ray diffractiometre (XRD), field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). A single phase solid solution alloy powder having body-centred cubic (BCC) structure with a lattice parameter of 3.15486 Å was obtained after milling for 32 hours.

  13. Improved Vemurafenib Dissolution and Pharmacokinetics as an Amorphous Solid Dispersion Produced by KinetiSol® Processing.

    PubMed

    Ellenberger, Daniel J; Miller, Dave A; Kucera, Sandra U; Williams, Robert O

    2018-03-14

    Vemurafenib is a poorly soluble, low permeability drug that has a demonstrated need for a solubility-enhanced formulation. However, conventional approaches for amorphous solid dispersion production are challenging due to the physiochemical properties of the compound. A suitable and novel method for creating an amorphous solid dispersion, known as solvent-controlled coprecipitation, was developed to make a material known as microprecipitated bulk powder (MBP). However, this approach has limitations in its processing and formulation space. In this study, it was hypothesized that vemurafenib can be processed by KinetiSol into the same amorphous formulation as MBP. The KinetiSol process utilizes high shear to rapidly process amorphous solid dispersions containing vemurafenib. Analysis of the material demonstrated that KinetiSol produced amorphous, single-phase material with acceptable chemical purity and stability. Values obtained were congruent to analysis conducted on the comparator material. However, the materials differed in particle morphology as the KinetiSol material was dense, smooth, and uniform while the MBP comparator was porous in structure and exhibited high surface area. The particles produced by KinetiSol had improved in-vitro dissolution and pharmacokinetic performance for vemurafenib compared to MBP due to slower drug nucleation and recrystallization which resulted in superior supersaturation maintenance during drug release. In the in-vivo rat pharmacokinetic study, both amorphous solid dispersions produced by KinetiSol exhibited mean AUC values at least two-fold that of MBP when dosed as a suspension. It was concluded that the KinetiSol process produced superior dosage forms containing vemurafenib with the potential for substantial reduction in patient pill burden.

  14. A Single-Phase Analytic Equation of State for Solid Polyurea and Polyurea Aerogels

    NASA Astrophysics Data System (ADS)

    Whitworth, Nicholas; Lambourn, Brian

    2017-06-01

    Commercially available polymers are commonly used as impactors in high explosive gas-gun experiments. This paper presents a relatively simple, single-phase, analytic equation of state (EoS) for solid polyurea and polyurea aerogels suitable for use in hydrocode simulations. An exponential shock velocity-particle velocity relation is initially fit to available Hugoniot data on the solid material, which has a density of 1.13 g/cm3. This relation is then converted to a finite strain relation along the principal isentrope, which is used as the reference curve for a Mie-Gruneisen form of EoS with an assumed form for the variation of Gruneisen Γ with specific volume. Using the solid EoS in conjunction with the Snowplough model for porosity, experimental data on the shock response of solid polyurea and polyurea aerogels with initial densities of 0.20 and 0.35 g/cm3 can be reproduced to a reasonable degree of accuracy. A companion paper at this conference describes the application of this and other EoS in modelling shock-release-reshock gas-gun experiments on the insensitive high explosive PBX 9502.

  15. Bis(trifluoromethylsulfonyl)imide-based frozen ionic liquid for the hollow-fiber solid-phase microextraction of dichlorodiphenyltrichloroethane and its main metabolites.

    PubMed

    Pang, Long; Yang, Peijie; Pang, Rong; Li, Shunyi

    2017-08-01

    1-Hexadecyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide is a solid-phase ionic organic material under ambient temperature and is considered as a kind of "frozen" ionic liquid. Because of their solid-state and ultra-hydrophobicity, "frozen" ionic liquids are able to be confined in the pores of hollow fiber, based on which a simple method was developed for the hollow-fiber solid-phase microextraction of dichlorodiphenyltrichloroethane and its main metabolites. Under optimized conditions, the proposed method results in good linearity (R 2 > 0.9965) over the range of 0.5-50 μg/L, with low limits of detection and quantification in the range of 0.33-0.38 and 1.00-1.25 μg/L, respectively. Intra- and interday precisions evaluated by relative standard deviation were 3-6 and 1-6%, respectively. The spiked recoveries of dichlorodiphenyltrichloroethane and its main metabolites from real water samples were in the range of 64-113 and 79-112%, respectively, at two different concentration levels. The results suggest that "frozen" ionic liquids are promising for use as a class of novel sorbents. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Quantitative experimental determination of the solid solution hardening potential of rhenium, tungsten and molybdenum in single-crystal nickel-based superalloys

    DOE PAGES

    Fleischmann, Ernst; Miller, Michael K.; Affeldt, Ernst; ...

    2015-01-31

    Here, the solid-solution hardening potential of the refractory elements rhenium, tungsten and molybdenum in the matrix of single-crystal nickel-based superalloys was experimentally quantified. Single-phase alloys with the composition of the nickel solid-solution matrix of superalloys were cast as single crystals, and tested in creep at 980 °C and 30–75 MPa. The use of single-phase single-crystalline material ensures very clean data because no grain boundary or particle strengthening effects interfere with the solid-solution hardening. This makes it possible to quantify the amount of rhenium, tungsten and molybdenum necessary to reduce the creep rate by a factor of 10. Rhenium is moremore » than two times more effective for matrix strengthening than either tungsten or molybdenum. The existence of rhenium clusters as a possible reason for the strong strengthening effect is excluded as a result of atom probe tomography measurements. If the partitioning coefficient of rhenium, tungsten and molybdenum between the γ matrix and the γ' precipitates is taken into account, the effectiveness of the alloying elements in two-phase superalloys can be calculated and the rhenium effect can be explained.« less

  17. Performance evaluation of extractor cutting blade configuration in Inulin extraction process from Dahlia sp. L tuber

    NASA Astrophysics Data System (ADS)

    Sundari, E.; Praputri, E.; Marthiana, W.; Jaya, M.

    2018-03-01

    Inulin, a polysaccharide plant-based nutrient, can be isolated from dahlia flower tubers by liquid-solid extraction processes and is generally carried out in an extractor tank equipped with an agitator. To accelerate the diffusion rate of solute from the solid phase (bulk phase) to the external surface (boundary layer) in order to increase yield of inulin, the size reduction of material is required. The purpose of this research was to design the cutting blade needed for dahlia tuber size reduction and investigate the effect of blade types, agitator speed (350, 700, 1050, and 1400 rpm), and configuration of cutting blade to material fineness at 90 minutes of contacting time. The results showed that higher cutting blade speed results in higher cut material fineness rate. The best conditions was achieved by the configuration of two four-blade turbine combined with one three-blade turbine with fineness rate more than 90% in 30 minutes of contacting time at every variation of agitator speed. The cutting blade designed in this study can be used for size reduction purpose of tubers other than dahlia tubers.

  18. Thermodynamic Phenomenology for Perovskite Structure Ferroelectric Solid Solutions with Morphotropic Phase Boundaries

    DTIC Science & Technology

    2005-12-13

    American Advanced Study Institute on Science and Technology of Ferroelectric Materials: Rosario Argentina, September 2002. a. Brief History of...zirconium-rich rhombohedral perovskite and the titani - composition. 8,𔄃) um-rich tetragonal perovskite phases. Within recent years, three factors have...of Physics. [DOI: 10.1063/1.1570517] The well-known elastoelectric coupling effects include When reviewing the history of flexoelectric investiga

  19. Geochemical, mineralogical and microbiological characteristics of sediment from a naturally reduced zone in a uranium-contaminated aquife

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Campbell, K M; K Kukkadapu, R K; Qafoku, N P

    2012-05-23

    Localized zones or lenses of naturally reduced sediments have the potential to play a significant role in the fate and transport of redox-sensitive metals and metalloids in aquifers. To assess the mineralogy, microbiology and redox processes that occur in these zones, several cores from a region of naturally occurring reducing conditions in a U-contaminated aquifer (Rifle, CO) were examined. Sediment samples from a transect of cores ranging from oxic/suboxic Rifle aquifer sediment to naturally reduced sediment were analyzed for U and Fe content, oxidation state, and mineralogy; reduced S phases; and solid-phase organic C content using a suite of analyticalmore » and spectroscopic techniques on bulk sediment and size fractions. Solid-phase U concentrations were higher in the naturally reduced zone, with a high proportion of the U present as U(IV). The sediments were also elevated in reduced S phases and Fe(II), indicating it is very likely that U(VI), Fe(III), and SO4 reduction has occurred or is occurring in the sediment. The microbial community was assessed using lipid- and DNA-based techniques, and statistical redundancy analysis was performed to determine correlations between the microbial community and the geochemistry. Increased concentrations of solid-phase organic C and biomass in the naturally reduced sediment suggests that natural bioreduction is stimulated by a zone of increased organic C concentration associated with fine-grained material and lower permeability to groundwater flow. Characterization of the naturally bioreduced sediment provides an understanding of the natural processes that occur in the sediment under reducing conditions and how they may impact natural attenuation of radionuclides and other redox sensitive materials. Results also suggest the importance of recalcitrant organic C for maintaining reducing conditions and U immobilization.« less

  20. Geochemical, mineralogical and microbiological characteristics of sediment from a naturally reduced zone in a uranium-contaminated aquifer

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Campbell, Kate M.; Kukkadapu, Ravi K.; Qafoku, Nikolla

    2012-05-23

    Localized zones or lenses of naturally reduced sediments have the potential to play a significant role in the fate and transport of redox-sensitive metals and metalloids in aquifers. To assess the mineralogy, microbiology, and redox processes that occur in these zones, we examined several cores from a region of naturally occurring reducing conditions in a uranium-contaminated aquifer (Rifle, CO). Sediment samples from a transect of cores ranging from oxic/suboxic Rifle aquifer sediment to naturally reduced sediment were analyzed for uranium and iron content, oxidation state, and mineralogy, reduced sulfur phases, and solid phase organic carbon content using a suite ofmore » analytical and spectroscopic techniques on bulk sediment and size fractions. Solid-phase uranium concentrations were higher in the naturally reduced zone, with a high proportion of the uranium present as reduced U(IV). The sediments were also elevated in reduced sulfur phases and Fe(II), indicating it is very likely that U(VI), Fe(III), and sulfate reduction occurred or is occurring in the sediment. The microbial community was assessed using lipid- and DNA-based techniques, and statistical redundancy analysis was performed to determine correlations between the microbial community and the geochemistry. Increased concentration of solid phase organic carbon and biomass in the naturally reduced sediment suggests that natural bioreduction is stimulated by a zone of increased organic carbon concentration associated with fine-grained material and lower permeability to groundwater flow. Characterization of the naturally bioreduced sediment provides an understanding of the natural processes that occur in the sediment under reducing conditions and how they may impact natural attenuation of radionuclides and other redox sensitive materials. Results also suggest the importance of recalcitrant organic carbon for maintaining reducing conditions and uranium immobilization.« less

  1. Geochemical, mineralogical and microbiological characteristics of sediment from a naturally reduced zone in a uranium-contaminated aquifer

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Campbell, K. M.; Kukkadapu, R. K.; Qafoku, N. P.

    2012-08-01

    Localized zones or lenses of naturally reduced sediments have the potential to play a significant role in the fate and transport of redox-sensitive metals and metalloids in aquifers. To assess the mineralogy, microbiology and redox processes that occur in these zones, several cores from a region of naturally occurring reducing conditions in a U-contaminated aquifer (Rifle, CO) were examined. Sediment samples from a transect of cores ranging from oxic/suboxic Rifle aquifer sediment to naturally reduced sediment were analyzed for U and Fe content, oxidation state, and mineralogy; reduced S phases; and solid-phase organic C content using a suite of analyticalmore » and spectroscopic techniques on bulk sediment and size fractions. Solid-phase U concentrations were higher in the naturally reduced zone, with a high proportion of the U present as U(IV). The sediments were also elevated in reduced S phases and Fe(II), indicating it is very likely that U(VI), Fe(III), and SO 4 reduction has occurred or is occurring in the sediment. The microbial community was assessed using lipid- and DNA-based techniques, and statistical redundancy analysis was performed to determine correlations between the microbial community and the geochemistry. Increased concentrations of solid-phase organic C and biomass in the naturally reduced sediment suggests that natural bioreduction is stimulated by a zone of increased organic C concentration associated with fine-grained material and lower permeability to groundwater flow. Characterization of the naturally bioreduced sediment provides an understanding of the natural processes that occur in the sediment under reducing conditions and how they may impact natural attenuation of radionuclides and other redox sensitive materials. Results also suggest the importance of recalcitrant organic C for maintaining reducing conditions and U immobilization.« less

  2. Solid state amorphization of metastable Al 0.5TiZrPdCuNi high entropy alloy investigated by high voltage electron microscopy

    DOE PAGES

    Nagase, Takeshi; Takeuchi, Akira; Amiya, Kenji; ...

    2017-07-18

    Here, the phase stability of high entropy alloy (HEA), Al 0.5TiZrPdCuNi, under fast electron irradiation was studied by in-situ high voltage electron microscopy (HVEM). The initial phase of this alloy quenched from the melt was dependent on cooling rate. At high cooling rates an amorphous phase was obtained, whereas a body-centered cubic ( b.c.c.) phase were obtained at low cooling rates. By thermal crystallization of the amorphous phase b.c.c. phase nano-crystals were formed. Upon fast electron irradiation solid state amorphization (SSA) was observed in b.c.c. phase regardless of the initial microstructure (i.e., “coarse crystalline structure” or “nano-crystalline structure with grainmore » boundaries as a sink for point defects”). SSA behavior in the Al 0.5TiZrPdCuNi HEAs was investigated by in-situ transmission electron microscopy observations. Because the amorphization is very rarely achieved in a solid solution phase under fast electron irradiation in common metallic materials, this result suggests that the Al 0.5TiZrPdCuNi HEA from other common alloys and the other HEAs. The differences in phase stability against the irradiation between the Al 0.5TiZrPdCuNi HEA and the other HEAs were discussed. This is the first experimental evidence of SSA in HEAs stimulated by fast electron irradiation.« less

  3. Influence of ignition process on mineral phase transformation in municipal solid waste incineration (MSWI) fly ash: Implications for estimating loss-on-ignition (LOI).

    PubMed

    Mu, Yue; Saffarzadeh, Amirhomayoun; Shimaoka, Takayuki

    2017-01-01

    This research focused on the mineral phase transformation under varied ignition conditions with the objective of estimating loss-on-ignition (LOI) parameter in municipal solid waste incineration (MSWI) fly ash residues. LOI is commonly used to measure the volatile species, unburned carbon and moisture in the solid materials. There are criteria for LOI measurement in some research fields, while there is no standard protocol for LOI measurement in MSWI fly ash. Using thermogravimetry technique, the ignition condition candidates were proposed at 440/700/900°C for 1 and 2h. Based on X-ray diffractometry results, obvious mineral phase transformation occurred as a function of ignition temperature variation rather than ignition time. Until 440°C, only some minor phases disappeared comparing with the original state. Significant mineral phase transformations of major phases (Ca- and Cl-based minerals) occurred between 440 and 700°C. The mineral phase transformation and the occurrence of newly-formed phases were determined not only by the ignition condition but also by the content of the co-existing components. Mineral phase components rarely changed when ignition temperature rose from 700 to 900°C. Consequently, in order to prevent critical damages to the original mineralogical composition of fly ash, the lowest ignition temperature (440°C) for 2h was suggested as an ideal measurement condition of LOI in MSWI fly ash. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Thermal modeling with solid/liquid phase change of the thermal energy storage experiment

    NASA Technical Reports Server (NTRS)

    Skarda, J. Raymond Lee

    1991-01-01

    A thermal model which simulates combined conduction and phase change characteristics of thermal energy storage (TES) materials is presented. Both the model and results are presented for the purpose of benchmarking the conduction and phase change capabilities of recently developed and unvalidated microgravity TES computer programs. Specifically, operation of TES-1 is simulated. A two-dimensional SINDA85 model of the TES experiment in cylindrical coordinates was constructed. The phase change model accounts for latent heat stored in, or released from, a node undergoing melting and freezing.

  5. Lindemann histograms as a new method to analyse nano-patterns and phases

    NASA Astrophysics Data System (ADS)

    Makey, Ghaith; Ilday, Serim; Tokel, Onur; Ibrahim, Muhamet; Yavuz, Ozgun; Pavlov, Ihor; Gulseren, Oguz; Ilday, Omer

    The detection, observation, and analysis of material phases and atomistic patterns are of great importance for understanding systems exhibiting both equilibrium and far-from-equilibrium dynamics. As such, there is intense research on phase transitions and pattern dynamics in soft matter, statistical and nonlinear physics, and polymer physics. In order to identify phases and nano-patterns, the pair correlation function is commonly used. However, this approach is limited in terms of recognizing competing patterns in dynamic systems, and lacks visualisation capabilities. In order to solve these limitations, we introduce Lindemann histogram quantification as an alternative method to analyse solid, liquid, and gas phases, along with hexagonal, square, and amorphous nano-pattern symmetries. We show that the proposed approach based on Lindemann parameter calculated per particle maps local number densities to material phase or particles pattern. We apply the Lindemann histogram method on dynamical colloidal self-assembly experimental data and identify competing patterns.

  6. Heat storage in alloy transformations

    NASA Technical Reports Server (NTRS)

    Birchenall, C. E.; Gueceri, S. I.; Farkas, D.; Labdon, M. B.; Nagaswami, N.; Pregger, B.

    1981-01-01

    The feasibility of using metal alloys as thermal energy storage media was determined. The following major elements were studied: (1) identification of congruently transforming alloys and thermochemical property measurements; (2) development of a precise and convenient method for measuring volume change during phase transformation and thermal expansion coefficients; (3) development of a numerical modeling routine for calculating heat flow in cylindrical heat exchangers containing phase change materials; and (4) identification of materials that could be used to contain the metal alloys. Several eutectic alloys and ternary intermetallic phases were determined. A method employing X-ray absorption techniques was developed to determine the coefficients of thermal expansion of both the solid and liquid phases and the volume change during phase transformation from data obtained during one continuous experimental test. The method and apparatus are discussed and the experimental results are presented. The development of the numerical modeling method is presented and results are discussed for both salt and metal alloy phase change media.

  7. Enhancing heat capacity of colloidal suspension using nanoscale encapsulated phase-change materials for heat transfer.

    PubMed

    Hong, Yan; Ding, Shujiang; Wu, Wei; Hu, Jianjun; Voevodin, Andrey A; Gschwender, Lois; Snyder, Ed; Chow, Louis; Su, Ming

    2010-06-01

    This paper describes a new method to enhance the heat-transfer property of a single-phase liquid by adding encapsulated phase-change nanoparticles (nano-PCMs), which absorb thermal energy during solid-liquid phase changes. Silica-encapsulated indium nanoparticles and polymer-encapsulated paraffin (wax) nanoparticles have been made using colloid method, and suspended into poly-alpha-olefin (PAO) and water for potential high- and low-temperature applications, respectively. The shells prevent leakage and agglomeration of molten phase-change materials, and enhance the dielectric properties of indium nanoparticles. The heat-transfer coefficients of PAO containing indium nanoparticles (30% by mass) and water containing paraffin nanoparticles (10% by mass) are 1.6 and 1.75 times higher than those of corresponding single-phase fluids. The structural integrity of encapsulation allows repeated use of such nanoparticles for many cycles in high heat generating devices.

  8. Evaluation of Cone Penetrometer Testing (CPT) for Use with Transportation Projects Phase 1

    DOT National Transportation Integrated Search

    2008-07-01

    The ODOT Office of Geotechnical Engineering (OGE) currently uses conventional drilling methods (e.g., hollow stem auger, solid stem auger) to perform subsurface investigations in unconsolidated materials. These techniques have been used for decades a...

  9. Mixed conductivity, structural and microstructural characterization of titania-doped yttria tetragonal zirconia polycrystalline/titania-doped yttria stabilized zirconia composite anode matrices

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Colomer, M.T., E-mail: tcolomer@icv.csic.e; Maczka, M.

    2011-02-15

    Taking advantage of the fact that TiO{sub 2} additions to 8YSZ cause not only the formation of a titania-doped YSZ solid solution but also a titania-doped YTZP solid solution, composite materials based on both solutions were prepared by solid state reaction. In particular, additions of 15 mol% of TiO{sub 2} give rise to composite materials constituted by 0.51 mol fraction titania-doped yttria tetragonal zirconia polycrystalline and 0.49 mol fraction titania-doped yttria stabilized zirconia (0.51TiYTZP/0.49TiYSZ). Furthermore, Y{sub 2}(Ti{sub 1-y}Zr{sub y}){sub 2}O{sub 7} pyrochlore is present as an impurity phase with y close to 1, according to FT-Raman results. Lower and highermore » additions of titania than that of 15 mol%, i.e., x=0, 5, 10, 20, 25 and 30 mol% were considered to study the evolution of 8YSZ phase as a function of the TiO{sub 2} content. Furthermore, zirconium titanate phase (ZrTiO{sub 4}) is detected when the titania content is equal or higher than 20 mol% and this phase admits Y{sub 2}O{sub 3} in solid solution according to FE-SEM-EDX. The 0.51TiYTZP/0.49TiYSZ duplex material was selected in this study to establish the mechanism of its electronic conduction under low oxygen partial pressures. In the pO{sub 2} range from 0.21 to 10{sup -7.5} atm. the conductivity is predominantly ionic and constant over the range and its value is 0.01 S/cm. The ionic plus electronic conductivity is 0.02 S/cm at 1000 {sup o}C and 10{sup -12.3} atm. Furthermore, the onset of electronic conductivity under reducing conditions exhibits a -1/4 pO{sub 2} dependence. Therefore, it is concluded that the n-type electronic conduction in the duplex material can be due to a small polaron-hopping between Ti{sup 3+} and Ti{sup 4+}. -- Graphical abstract: FE-SEM micrograph of a polished and thermal etched surface of a Ti-doped YTZP/Ti-doped YSZ composite material. Display Omitted Research highlights: {yields} Ti-doped YTZP/Ti-doped YSZ composite materials are mixed conductors under low partial pressures. {yields} From 5 mol% of TiO{sub 2}, Y{sub 2}(Ti{sub 1-y},Zr{sub y}){sub 2}O{sub 7} pyrochlore is present as a minor phase, being y close to 1 according to FT-Raman studies. {yields} The onset of the electronic conductivity under reducing conditions exhibit a -1/4 pO{sub 2} dependence. The n-type electronic conduction is due to a small polaron-hopping between Ti{sup 3+} and Ti{sup 4+}.« less

  10. Measurement of a solid-state triple point at the metal-insulator transition in VO2.

    PubMed

    Park, Jae Hyung; Coy, Jim M; Kasirga, T Serkan; Huang, Chunming; Fei, Zaiyao; Hunter, Scott; Cobden, David H

    2013-08-22

    First-order phase transitions in solids are notoriously challenging to study. The combination of change in unit cell shape, long range of elastic distortion and flow of latent heat leads to large energy barriers resulting in domain structure, hysteresis and cracking. The situation is worse near a triple point, where more than two phases are involved. The well-known metal-insulator transition in vanadium dioxide, a popular candidate for ultrafast optical and electrical switching applications, is a case in point. Even though VO2 is one of the simplest strongly correlated materials, experimental difficulties posed by the first-order nature of the metal-insulator transition as well as the involvement of at least two competing insulating phases have led to persistent controversy about its nature. Here we show that studying single-crystal VO2 nanobeams in a purpose-built nanomechanical strain apparatus allows investigation of this prototypical phase transition with unprecedented control and precision. Our results include the striking finding that the triple point of the metallic phase and two insulating phases is at the transition temperature, Ttr = Tc, which we determine to be 65.0 ± 0.1 °C. The findings have profound implications for the mechanism of the metal-insulator transition in VO2, but they also demonstrate the importance of this approach for mastering phase transitions in many other strongly correlated materials, such as manganites and iron-based superconductors.

  11. Thermodynamic Properties of CO{sub 2} Capture Reaction by Solid Sorbents: Theoretical Predictions and Experimental Validations

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Duan, Yuhua; Luebke, David; Pennline, Henry

    2012-01-01

    It is generally accepted that current technologies for capturing CO{sub 2} are still too energy intensive. Hence, there is a critical need for development of new materials that can capture CO{sub 2} reversibly with acceptable energy costs. Accordingly, solid sorbents have been proposed to be used for CO{sub 2} capture applications through a reversible chemical transformation. By combining thermodynamic database mining with first principles density functional theory and phonon lattice dynamics calculations, a theoretical screening methodology to identify the most promising CO{sub 2} sorbent candidates from the vast array of possible solid materials has been proposed and validated. The calculatedmore » thermodynamic properties of different classes of solid materials versus temperature and pressure changes were further used to evaluate the equilibrium properties for the CO{sub 2} adsorption/desorption cycles. According to the requirements imposed by the pre- and post- combustion technologies and based on our calculated thermodynamic properties for the CO{sub 2} capture reactions by the solids of interest, we were able to screen only those solid materials for which lower capture energy costs are expected at the desired pressure and temperature conditions. These CO{sub 2} sorbent candidates were further considered for experimental validations. In this presentation, we first introduce our screening methodology with validating by solid dataset of alkali and alkaline metal oxides, hydroxides and bicarbonates which thermodynamic properties are available. Then, by studying a series of lithium silicates, we found that by increasing the Li{sub 2}O/SiO{sub 2} ratio in the lithium silicates their corresponding turnover temperatures for CO{sub 2} capture reactions can be increased. Compared to anhydrous K{sub 2}CO{sub 3}, the dehydrated K{sub 2}CO{sub 3}1.5H{sub 2}O can only be applied for post-combustion CO{sub 2} capture technology at temperatures lower than its phase transition (to anhydrous phase) temperature, which depends on the CO{sub 2} pressure and the steam pressure with the best range being PH{sub 2}O≤1.0 bar. Above the phase-transition temperature, the sorbent will be regenerated into anhydrous K{sub 2}CO{sub 3}. Our theoretical investigations on Na-promoted MgO sorbents revealed that the sorption process takes place through formation of the Na{sub 2}Mg(CO{sub 3}){sub 2} double carbonate with better reaction kinetics over porous MgO, that of pure MgO sorbent. The experimental sorption tests also indicated that the Na-promoted MgO sorbent has high reactivity and capacity towards CO{sub 2} sorption and can be easily regenerated either through pressure or temperature swing processes.« less

  12. Hydrogen and related materials at high density: Physics, chemistry and planetary implications

    NASA Technical Reports Server (NTRS)

    Hemley, R. J.; Mao, H. K.; Duffy, T. S.; Goncharov, A.; Vos, W.; Zha, C. S.; Eggert, J. H.; Li, M.; Hanfland, M.

    1994-01-01

    Recent studies of low-Z molecular materials including hydrogen to multimegabar pressures (less than 300 GPa) have uncovered a range of phenomena relevant to understanding the nature of the interiors of the outer planets and their satellites. Synchrotron x ray diffraction measurements (to 42 GPa) have been used to determine the crystal structure of the solid (hexagonal-close packed) and equation of state. Sound velocities in fluid and solid hydrogen (to 24 GPa) have been inverted to obtain elastic constants and aggregate bulk and shear moduli. In addition, an improved intermolecular potential has been determined which fits both static and shock-wave data. Use of the new potential for the molecular envelope of Jupiter suggests the need for major revisions of existing Jovian models or a reanalysis of reported free oscillations for the planet. Studies at higher pressures (greater than 100 GPa) reveal a sequence of pressure-induced symmetry-breaking transitions in molecular hydrogen, giving rise to three high-pressure phases (1, 2, and 3). Phase 1 is the rotationally disordered hcp phase which persists from low pressure to well above 100 GPa at high temperature (e.g., 300 K). Phase 2 is a low-temperature, high-pressure phase (transition at 100 GPa and 77 K in H2) with spectral features indicative of partial rotational ordering and crystallographic distortion. The transition to Phase 3 at 150 GPa is accompanied by a weakening of the molecular bond, gradual changes in orientational ordering, strong enhancement of the infrared intramolecular vibrational absorption, and strong intermolecular interactions similar to those of ambient-pressure network solids. Studies of the phase diagram reveal a triple point near 130 K and 160 GPa. Higher pressure measurements of vibrational spectra place a lower bound of approximately 250 GPa on the predicted transition pressure for dissociation of molecular hydrogen to form a monatomic metal.

  13. Nature of hardness evolution in nanocrystalline NiTi shape memory alloys during solid-state phase transition

    PubMed Central

    Amini, Abbas; Cheng, Chun

    2013-01-01

    Due to a distinct nature of thermomechanical smart materials' reaction to applied loads, a revolutionary approach is needed to measure the hardness and to understand its size effect for pseudoelastic NiTi shape memory alloys (SMAs) during the solid-state phase transition. Spherical hardness is increased with depths during the phase transition in NiTi SMAs. This behaviour is contrary to the decrease in the hardness of NiTi SMAs with depths using sharp tips and the depth-insensitive hardness of traditional metallic alloys using spherical tips. In contrast with the common dislocation theory for the hardness measurement, the nature of NiTi SMAs' hardness is explained by the balance between the interface and the bulk energy of phase transformed SMAs. Contrary to the energy balance in the indentation zone using sharp tips, the interface energy was numerically shown to be less dominant than the bulk energy of the phase transition zone using spherical tips. PMID:23963305

  14. Quaternary ammonium-functionalized silica sorbents for the solid-phase extraction of aromatic amines under normal phase conditions.

    PubMed

    Vidal, Lorena; Robin, Orlane; Parshintsev, Jevgeni; Mikkola, Jyri-Pekka; Riekkola, Marja-Liisa

    2013-04-12

    Quaternary ammonium-functionalized silica materials were synthesized and applied for solid-phase extraction (SPE) of aromatic amines, which are classified as priority pollutants by US Environmental Protection Agency. Hexamethylenetetramine used for silica surface modification for the first time was employed as SPE sorbent under normal phase conditions. Hexaminium-functionalized silica demonstrated excellent extraction efficiencies for o-toluidine, 4-ethylaniline and quinoline (recoveries 101-107%), while for N,N-dimethylaniline and N-isopropylaniline recoveries were from low to moderate (14-46%). In addition, the suitability of 1-alkyl-3-(propyl-3-sulfonate) imidazolium-functionalized silica as SPE sorbent was tested under normal phase conditions. The recoveries achieved for the five aromatic amines ranged from 89 to 99%. The stability of the sorbent was evaluated during and after 150 extractions. Coefficients of variation between 4.5 and 10.2% proved a high stability of the synthesized sorbent. Elution was carried out using acetonitrile in the case of hexaminium-functionalized silica and water for 1-alkyl-3-(propyl-3-sulfonate) imidazolium-functionalized silica sorbent. After the extraction the analytes were separated and detected by liquid chromatography ultraviolet detection (LC-UV). The retention mechanism of the materials was primarily based on polar hydrogen bonding and π-π interactions. Comparison made with activated silica proved the quaternary ammonium-functionalized materials to offer different selectivity and better extraction efficiencies for aromatic amines. Finally, 1-alkyl-3-(propyl-3-sulfonate) imidazolium-functionalized silica sorbent was successfully tested for the extraction of wastewater and soil samples. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. High-temperature solution growth and characterization of (1-x)PbTiO3-xBi(Zn2/3Nb1/3)O3 piezo-/ferroelectric single crystals

    NASA Astrophysics Data System (ADS)

    Paterson, Alisa R.; Zhao, Jinyan; Liu, Zenghui; Wu, Xiaoqing; Ren, Wei; Ye, Zuo-Guang

    2018-03-01

    Complex perovskite PbTiO3-Bi(Me‧Me″)O3 solid solutions represent new materials systems that possess a higher Curie temperature (TC) than the relaxor-PbTiO3 solid solutions, and are useful for potential applications. To this end, novel ferroelectric single crystals of the (1-x)PbTiO3-xBi(Zn2/3Nb1/3)O3 (PT-BZN) solid solution were successfully grown by the high-temperature solution growth (HTSG) method. Powder X-ray diffraction shows that the symmetry of the grown crystals is tetragonal. The dielectric permittivity and optical domain structures were characterized by dielectric measurements and polarized light microscopy, respectively, as a function of temperature, revealing a first-order ferroelectric-paraelectric phase transition at a TC of 436 ± 2 °C. Based on the TC, the average composition of the crystal platelet was estimated to be 0.58PT-0.42BZN. Piezoresponse force microscopy measurements of the phase and amplitude as a function of voltage reveal the complex polar domain structure and demonstrate the ferroelectric switching behaviour of these materials. These results suggest that the PT-BZN single crystals indeed form a new family of high TC piezo-/ferroelectric materials which are potentially useful for the fabrication of electromechanical transducers for high-temperature applications.

  16. Magnetic ferrite particles combined with electrothermal atomic absorption spectrometry for the speciation of low concentrations of arsenic.

    PubMed

    López-García, Ignacio; Marín-Hernández, Juan José; Hernández-Córdoba, Manuel

    2018-05-01

    Freshly in situ prepared ferrite particles were used for the micro-solid phase extraction of arsenic species. When the separation was carried out at pH 8, inorganic arsenic (As(III) + As(V)) and monomethylarsonic acid (MMA) were retained in the magnetic material. A second aliquot was treated with 2,3 dimercapto propanol, leading to the retention of As(V)+MMA, while a third aliquot was first treated with sodium thiosulphate, in which case only inorganic arsenic passed to the solid phase. In all cases, the solid residue collected by a magnet was suspended in a dilute nitric acid solution containing Triton X-100 and introduced into the electrothermal atomizer to obtain the analytical signal of arsenic. The use of palladium as a chemical modifier allowed calibration to be carried out with aqueous standards. The detection limit was 0.02µgL -1 arsenic for a 10mL sample volume. The procedure was applied to waters and herbal infusions, and its reliability was evaluated by analyzing eleven certified reference materials for which speciation data are provided. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Advanced methods for preparation and characterization of infrared detector materials. [mercury cadmium telluride alloys

    NASA Technical Reports Server (NTRS)

    Lehoczky, S. L.; Szofran, F. R.

    1981-01-01

    Differential thermal analysis data were obtained on mercury cadmium telluride alloys in order to establish the liquidus temperatures for the various alloy compositions. Preliminary theoretical analyses was performed to establish the ternary phase equilibrium parameters for the metal rich region of the phase diagram. Liquid-solid equilibrium parameters were determined for the pseudobinary alloy system. Phase equilibrium was calculated and Hg(l-x) Cd(x) Te alloys were directionally solidified from pseudobinary melts. Electrical resistivity and Hall coefficient measurements were obtained.

  18. 3D Porous Nanoarchitectures Derived from SnS/S-Doped Graphene Hybrid Nanosheets for Flexible All-Solid-State Supercapacitors.

    PubMed

    Liu, Chunyan; Zhao, Shulin; Lu, Yanan; Chang, Yingxue; Xu, Dongdong; Wang, Qi; Dai, Zhihui; Bao, Jianchun; Han, Min

    2017-03-01

    3D porous nanoarchitectures derived from SnS/S-doped graphene hybrid nanosheets are successfully prepared by controllable thermal conversion of oleylamine-capped mixed-phase SnS 2 -SnS nanodisks precursors, and employed as electroactive material to fabricate flexible, symmetric, all-solid-state supercapacitors. The fabricated solid devices exhibit very high areal specific capacitance (2.98 mF cm -2 ), good cycling stability (99% for 10 000 cycles), excellent flexibility, and desirable mechanical stability. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Solid-state polymerisation via [2+2] cycloaddition reaction involving coordination polymers.

    PubMed

    Medishetty, Raghavender; Park, In-Hyeok; Lee, Shim Sung; Vittal, Jagadese J

    2016-03-14

    Highly crystalline metal ions containing organic polymers are potentially useful to manipulate the magnetic and optical properties to make advanced multifunctional materials. However, it is challenging to synthesise monocrystalline metal complexes of organic polymers and single-phase hybrid materials made up of both coordination and organic polymers by traditional solution crystallisation. This requires an entirely different approach in the solid-state by thermal or photo polymerisation of the ligands. Among the photochemical methods available, [2+2] cycloaddition reaction has been recently employed to generate cyclobutane based coordination polymers from the metal complexes. Cyclobutane polymers have also been integrated into coordination polymers in this way. Recent advancements in the construction of polymeric chains of cyclobutane rings through photo-dimerisation reaction in the monocrystalline solids containing metal complexes, coordination polymers and metal-organic framework structures are discussed here.

  20. Molten salt synthesis of nanocrystalline phase of high dielectric constant material CaCu3Ti4O12.

    PubMed

    Prakash, B Shri; Varma, K B R

    2008-11-01

    Nanocrystalline powders of giant dielectric constant material, CaCu3Ti4O12 (CCTO), have been prepared successfully by the molten salt synthesis (MSS) using KCl at 750 degrees C/10 h, which is significantly lower than the calcination temperature (approximately 1000 degrees C) that is employed to obtain phase pure CCTO in the conventional solid-state reaction route. The water washed molten salt synthesized powder, characterized by X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), and Transmission electron microscopy (TEM) confirmed to be a phase pure CCTO associated with approximately 150 nm sized crystallites of nearly spherical shape. The decrease in the formation temperature/duration of CCTO in MSS method was attributed to an increase in the diffusion rate or a decrease in the diffusion length of reacting ions in the molten salt medium. As a consequence of liquid phase sintering, pellets of as-synthesized KCl containing CCTO powder exhibited higher sinterability and grain size than that of KCl free CCTO samples prepared by both MSS method and conventional solid-state reaction route. The grain size and the dielectric constant of KCl containing CCTO ceramics increased with increasing sintering temperature (900 degrees C-1050 degrees C). Indeed the dielectric constants of these ceramics were higher than that of KCl free CCTO samples prepared by both MSS method and those obtained via the solid-state reaction route and sintered at the same temperature. Internal barrier layer capacitance (IBLC) model was invoked to correlate the observed dielectric constant with the grain size in these samples.

  1. Ionic Conductivity of TlBr1-xIx(x = 0, 0.2, 1): Candidate Gamma Ray Detector

    NASA Astrophysics Data System (ADS)

    Bishop, S. R.; Ciampi, G.; Lee, C. D.; Kuhn, M.; Tuller, H. L.; Higgins, W.; Shah, K. S.

    2012-10-01

    The ionic conductivity of TlBr, TlI and their solid solutions, candidates for high energy radiation detection, was examined using impedance spectroscopy. The orthorhombic to cubic phase change in TlI was observed via a steep change in conductivity with increasing temperature, whereas the TlBr-TlI solid solution was cubic throughout the measured temperature range, in agreement with the literature. The intrinsic conductivity of the cubic phase of each material showed nearly identical behavior, indicating that I substitution for Br has little to no effect on the combined defect formation and transport parameters in the studied range. Additionally, optical transmission was correlated with I concentration.

  2. Thermodynamically constrained correction to ab initio equations of state

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    French, Martin; Mattsson, Thomas R.

    2014-07-07

    We show how equations of state generated by density functional theory methods can be augmented to match experimental data without distorting the correct behavior in the high- and low-density limits. The technique is thermodynamically consistent and relies on knowledge of the density and bulk modulus at a reference state and an estimation of the critical density of the liquid phase. We apply the method to four materials representing different classes of solids: carbon, molybdenum, lithium, and lithium fluoride. It is demonstrated that the corrected equations of state for both the liquid and solid phases show a significantly reduced dependence ofmore » the exchange-correlation functional used.« less

  3. Modeling of sorption processes on solid-phase ion-exchangers

    NASA Astrophysics Data System (ADS)

    Dorofeeva, Ludmila; Kuan, Nguyen Anh

    2018-03-01

    Research of alkaline elements separation on solid-phase ion-exchangers is carried out to define the selectivity coefficients and height of an equivalent theoretical stage for both continuous and stepwise filling of column by ionite. On inorganic selective sorbents the increase in isotope enrichment factor up to 0.0127 is received. Also, parametrical models that are adequately describing dependence of the pressure difference and the magnitude expansion in the ion-exchange layer from the flow rate and temperature have been obtained. The concentration rate value under the optimum realization conditions of process and depending on type of a selective material changes in a range 1.021÷1.092. Calculated results show agreement with experimental data.

  4. The autowave modes of solid phase polymerization of metal-containing monomers in two- and three-dimensional fiberglass-filled matrices

    NASA Astrophysics Data System (ADS)

    Barelko, V. V.; Pomogailo, A. D.; Dzhardimalieva, G. I.; Evstratova, S. I.; Rozenberg, A. S.; Uflyand, I. E.

    1999-06-01

    The phenomenon of autowave (frontal) solid phase polymerization of metal-containing monomers based on metal-acrylamide complexes is considered. The comparison of the features of autowave processes realized in both the single-component matrices of the monomer and the matrices filled by the fiberglass materials is performed. The unstable regimes of the polymerization wave as well as the conditions for the stabilization of the flat front in the filled matrices are described. The peculiarities of the frontal regimes in the three- and two-dimensional media are studied. Some possibilities for using of autowave polymerization in the fabrication of the polymer-fiberglass composites and composition prepregs are discussed.

  5. Solid-phase data from cores at the proposed Dewey Burdock uranium in-situ recovery mine, near Edgemont, South Dakota

    USGS Publications Warehouse

    Johnson, Raymond H.; Diehl, Sharon F.; Benzel, William M.

    2013-01-01

    This report releases solid-phase data from cores at the proposed Dewey Burdock uranium in-situ recovery site near Edgemont, South Dakota. These cores were collected by Powertech Uranium Corporation, and material not used for their analyses were given to the U.S. Geological Survey for additional sampling and analyses. These additional analyses included total carbon and sulfur, whole rock acid digestion for major and trace elements, 234U/238U activity ratios, X-ray diffraction, thin sections, scanning electron microscopy analyses, and cathodoluminescence. This report provides the methods and data results from these analyses along with a short summary of observations.

  6. (U) Equation of State and Compaction Modeling for CeO 2

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Fredenburg, David A.; Chisolm, Eric D.

    2014-10-20

    Recent efforts have focused on developing a solid-liquid and three-phase equation of state (EOS) for CeO 2, while parallel experimental efforts have focused on obtaining high-fidelity Hugoniot measurements on CeO 2 in the porous state. The current work examines the robustness of two CeO 2 SESAME equations of state, a solid-liquid EOS, 96170, and a three-phase EOS, 96171, by validating the EOS against a suite of high-pressure shock compression experiments on initially porous CeO 2. At lower pressures compaction is considered by incorporating a two-term exponential form of the P-compaction model, using three separate definitions for α(P). Simulations are executedmore » spanning the partially compacted and fully compacted EOS regimes over the pressure range 0.5 - 109 GPa. Comparison of calculated Hugoniot results with those obtained experimentally indicate good agreement for all definitions of α(P) with both the solid-liquid and three-phase EOS in the low-pressure compaction regime. At higher pressures the three-phase EOS does a better job at predicting the measured Hugoniot response, though at the highest pressures EOS 96171 predicts a less compliant response than is observed experimentally. Measured material velocity profiles of the shock-wave after it has transmitted through the powder are also compared with those simulated using with solid-liquid and three-phase EOS. Profiles lend insight into limits of the current experimental design, as well as the threshold conditions for the shock-induced phase transition in CeO 2.« less

  7. Characterization of a water-solid interaction in a partially ordered system.

    PubMed

    Chakravarty, Paroma; Lubach, Joseph W

    2013-11-04

    GNE068-PC, a developmental compound, was previously characterized to be mesomorphous, i.e. having long-range order associated with significant local molecular disorder (Chakravarty et. al., Mol. Pharmaceutics, accepted). The compound was exposed to moisture under different relative humidity conditions ranging from 11% to 60% RH at room temperature (RT) for 7 days, and the resultant product phases were characterized. The partially ordered sample progressively lost crystallinity (long-range order) and birefringence (orientational order) upon exposure to increasing RH conditions, leading to the formation of a completely disordered amorphous phase at 60% RH (RT). Long-range positional order was irrecoverable even after moisture removal from the sample exposed to 60% RH. This was attributed to replacement of residual ethyl acetate by water, the former being critical for maintenance of long-range order in the material. In addition, water sorption appeared to irreversibly alter the molecular orientation, thereby affecting sample birefringence. Solid-state NMR revealed increases in (1)H and (13)C spin-lattice relaxation times (T1) going from the mesomorphous phase to the fully amorphous phase. This was indicative of reduction in lattice mobility, likely due to the decreased motion of the aromatic portions of the molecule, in particular C17, which showed the most dramatic increase in (13)C T1. This is likely due to decrease in available free volume upon water sorption. Drying of the hydrated disordered phase showed somewhat greater mobility than the hydrated phase, likely due to increased relative free volume through removal of water. A water-solid interaction therefore irreversibly changed the solid-state makeup of GNE068-PC.

  8. Synthesis and Raman spectroscopy of a layered SiS2 phase at high pressures

    NASA Astrophysics Data System (ADS)

    Wang, Yu; Jiang, Shu-Qing; Goncharov, Alexander F.; Gorelli, Federico A.; Chen, Xiao-Jia; Plašienka, Dušan; MartoÅák, Roman; Tosatti, Erio; Santoro, Mario

    2018-01-01

    Dichalcogenides are known to exhibit layered solid phases, at ambient and high pressures, where 2D layers of chemically bonded formula units are held together by van der Waals forces. These materials are of great interest for solid-state sciences and technology, along with other 2D systems such as graphene and phosphorene. SiS2 is an archetypal model system of the most fundamental interest within this ensemble. Recently, high pressure (GPa) phases with Si in octahedral coordination by S have been theoretically predicted and also experimentally found to occur in this compound. At variance with stishovite in SiO2, which is a 3D network of SiO6 octahedra, the phases with octahedral coordination in SiS2 are 2D layered. Very importantly, this type of semiconducting material was theoretically predicted to exhibit continuous bandgap closing with pressure to a poor metallic state at tens of GPa. We synthesized layered SiS2 with octahedral coordination in a diamond anvil cell at 7.5-9 GPa, by laser heating together elemental S and Si at 1300-1700 K. Indeed, Raman spectroscopy up to 64.4 GPa is compatible with continuous bandgap closing in this material with the onset of either weak metallicity or of a narrow bandgap semiconductor state with a large density of defect-induced, intra-gap energy levels, at about 57 GPa. Importantly, our investigation adds up to the fundamental knowledge of layered dichalcogenides.

  9. The Local Atomic Structure and Chemical Bonding in Sodium Tin Phases

    DOE PAGES

    Baggetto, Loic; Bridges, Craig A.; Jumas, Dr. Jean-Claude; ...

    2014-09-25

    To understand these electrochemically-derived materials we have reinvestigated the formation of Na-Sn alloys to identify all the phases which form when x ≥ 1 (NaxSn) and characterized the local bonding around the Sn atoms with X-ray diffraction, 119Sn M ssbauer spectroscopy, and X-ray absorption spectroscopies. The results from the well-defined crystallographic materials were compared to the spectroscopic measurements of the local Sn structures in the electrochemically prepared materials. The reinvestigation of the Na-Sn compounds yields a number of new results: (i) Na 7Sn 3 is a new thermodynamically-stable phase with a rhombohedral structure and R-3m space group; (ii) orthorhombic Namore » 9Sn 4 (Cmcm) has relatively slow formation kinetics suggesting why it does not form at room temperature during the electrochemical reaction; (iii) orthorhombic Na 14.78Sn 4 (Pnma), better described as Na 16-xSn 4, is Na-richer than cubic Na 15Sn 4 (I-43d). Characterization of electrochemically prepared Na-Sn alloys indicate that, at the exception of Na 7Sn 3 and Na 15Sn 4, different crystal structures than similar Na-Sn compositions prepared via classic solid state reactions are formed. These phases are composed of disordered structures characteristic of kinetic-driven solid-state amorphization reactions. In these structures, Sn coordinates in asymmetric environments, which differ significantly from the environments present in Na-Sn model compounds.« less

  10. Spray-formed tooling

    NASA Astrophysics Data System (ADS)

    McHugh, K. M.; Key, J. F.

    The United States Council for Automotive Research (USCAR) has formed a partnership with the Idaho National Engineering Laboratory (INEL) to develop a process for the rapid production of low-cost tooling based on spray forming technology developed at the INEL. Phase 1 of the program will involve bench-scale system development, materials characterization, and process optimization. In Phase 2, prototype systems will be designed, constructed, evaluated, and optimized. Process control and other issues that influence commercialization will be addressed during this phase of the project. Technology transfer to USCAR, or a tooling vendor selected by USCAR, will be accomplished during Phase 3. The approach INEL is using to produce tooling, such as plastic injection molds and stamping dies, combines rapid solidification processing and net-shape materials processing into a single step. A bulk liquid metal is pressure-fed into a de Laval spray nozzle transporting a high velocity, high temperature inert gas. The gas jet disintegrates the metal into fine droplets and deposits them onto a tool pattern made from materials such as plastic, wax, clay, ceramics, and metals. The approach is compatible with solid freeform fabrication techniques such as stereolithography, selective laser sintering, and laminated object manufacturing. Heat is extracted rapidly, in-flight, by convection as the spray jet entrains cool inert gas to produce undercooled and semi-solid droplets. At the pattern, the droplets weld together while replicating the shape and surface features of the pattern. Tool formation is rapid; deposition rates in excess of 1 ton/h have been demonstrated for bench-scale nozzles.

  11. In situ neutron scattering study of nanoscale phase evolution in PbTe-PbS thermoelectric material

    DOE PAGES

    Ren, Fei; Schmidt, Robert; Keum, Jong K.; ...

    2016-08-24

    Introducing nanostructural second phases has been proved to be an effective approach to reduce the lattice thermal conductivity and thus enhance the figure of merit for many thermoelectric materials. Furthermore studies of the formation and evolution of these second phases are central to understanding temperature dependent material behavior, improving thermal stabilities, as well as designing new materials. We examined powder samples of PbTe-PbS thermoelectric material using in situ neutron diffraction and small angle neutron scattering (SANS) techniques from room temperature to elevated temperature up to 663 K, to explore quantitative information on the structure, weight fraction, and size of themore » second phase. Neutron diffraction data showed the as-milled powder was primarily solid solution before heat treatment. During heating, PbS second phase precipitated out of the PbTe matrix around 480 K, while re-dissolution started around 570 K. The second phase remained separated from the matrix upon cooling. Furthermore, SANS data indicated there are two populations of nanostructures. The size of the smaller nanostructure increased from initially 5 nm to approximately 25 nm after annealing at 650 K, while the size of the larger nanostructure remained unchanged. Our study demonstrated that in situ neutron techniques are effective means to obtain quantitative information to study temperature dependent nanostructural behavior of thermoelectrics and likely other high-temperature materials.« less

  12. Liquid-like ionic conduction in solid lithium and sodium monocarba- closo-decaborates near or at room temperature

    DOE PAGES

    Tang, Wan Si; Matsuo, Motoaki; Wu, Hui; ...

    2016-02-05

    Both LiCB 9H 10 and NaCB 9H 10 exhibit liquid-like cationic conductivities (≥0.03 S cm –1) in their disordered hexagonal phases near or at room temperature. Furthermore, these unprecedented conductivities and favorable stabilities enabled by the large pseudoaromatic polyhedral anions render these materials in their pristine or further modified forms as promising solid electrolytes in next-generation, power devices.

  13. Stabilization of superionic α-Agl at room temperature in a glass matrix

    NASA Astrophysics Data System (ADS)

    Tatsumisago, Masahiro; Shinkuma, Yoshikane; Minami, Tsutomu

    1991-11-01

    SINCE the discovery1 that the high-temperature phase of silver iodide (α-AgI) has an ionic conductivity comparable to that of the best liquid electrolytes, solid electrolytes have attracted wide interest. Possible applications of these materials range from solid-state batteries to electrochromic displays and sensors2. Although α-AgI displays conductivities of more than 10 S cm-1 (ref. 3), owing to the almost liquid-like mobility of Ag+ ions, the crystal transforms below 147 °C to the β-phase with a conductivity of only ~10-5 S cm-1 at room temperature. Efforts to achieve good conductivities at lower temperatures have focused on the addition of a second component to AgI to form solid solutions or new compounds such as RbAg4I5 and Ag2HgI4 (refs 4-7). Here we report our success in depressing the α-->β transformation temperature so as to stabilize α-AgI itself at room temperature. We use a melt-quenching technique to prepare crystallites of α-AgI frozen into a silver borate glass matrix. The quenched material showed diffraction peaks characteristic of α-AgI and displayed ionic conductivities of about 10-1 S cm-1. Further development of these glass/crystal composites may make the high ionic conductivity of α-AgI available for room-temperature solid-state applications.

  14. Halloysite nanotubes as a solid sorbent in ultrasound-assisted dispersive micro solid-phase extraction for the determination of bismuth in water samples using high-resolution continuum source graphite-furnace atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Krawczyk-Coda, Magdalena

    2017-03-01

    In this research, a simple, accurate, and inexpensive preconcentration procedure was developed for the determination of bismuth in water samples, using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR CS GFAAS). During the preconcentration step, halloysite nanotubes (HNTs) were used as a solid sorbent in ultrasound-assisted dispersive micro solid-phase extraction (USA DMSPE). The influence of the pH of the sample solution, amount of HNTs, and extraction time, as well as of the main parameters of HR CS GFAAS, on absorbance was investigated. The limit of detection was 0.005 μg L- 1. The preconcentration factor achieved for bismuth was 32. The relative standard deviation (RSD) was 4%. The accuracy of this method was validated by analyses of NIST SRM 1643e (Trace elements in water) and TMDA-54.5 (A high level fortified sample for trace elements) certified reference materials. The measured bismuth contents in these certified reference materials were in satisfactory agreement with the certified values according to the t-test for a 95% confidence level. The proposed method has been successfully applied to the determination of bismuth in five different real water samples (seawater, lake water, river water, stream water and rain water).

  15. Piezoelectric Ceramics of the (1 − x)Bi0.50Na0.50TiO3–xBa0.90Ca0.10TiO3 Lead-Free Solid Solution: Chemical Shift of the Morphotropic Phase Boundary, a Case Study for x = 0.06

    PubMed Central

    Vivar-Ocampo, Rodrigo; Pardo, Lorena; Ávila, David; Morán, Emilio; González, Amador M.; Bucio, Lauro; Villafuerte-Castrejón, María-Elena

    2017-01-01

    Research and development of lead-free piezoelectric materials are still the hottest topics in the field of piezoelectricity. One of the most promising lead-free family of compounds to replace lead zirconate–titanate for actuators is that of Bi0.50Na0.50TiO3 (BNT) based solid solutions. The pseudo-binary (1 − x)Bi0.50Na0.50TiO3–xBa1 − yCayTiO3 system has been proposed for high temperature capacitors and not yet fully explored as piezoelectric material. In this work, the solid solution with x = 0.06 and y = 0.10 was obtained by two different synthesis routes: solid state and Pechini, aiming at using reduced temperatures, both in synthesis (<800 °C) and sintering (<1150 °C), while maintaining appropriated piezoelectric performance. Crystal structure, ceramic grain size, and morphology depend on the synthesis route and were analyzed by X-ray diffraction, together with scanning and transmission electron microscopy. The effects of processing and ceramic microstructure on the structural, dielectric, ferroelectric, and piezoelectric properties were discussed in terms of a shift of the Morphotropic Phase Boundary, chemically induced by the synthesis route. PMID:28773096

  16. Piezoelectric Ceramics of the (1 - x)Bi0.50Na0.50TiO₃-xBa0.90Ca0.10TiO₃ Lead-Free Solid Solution: Chemical Shift of the Morphotropic Phase Boundary, a Case Study for x = 0.06.

    PubMed

    Vivar-Ocampo, Rodrigo; Pardo, Lorena; Ávila, David; Morán, Emilio; González, Amador M; Bucio, Lauro; Villafuerte-Castrejón, María-Elena

    2017-07-01

    Research and development of lead-free piezoelectric materials are still the hottest topics in the field of piezoelectricity. One of the most promising lead-free family of compounds to replace lead zirconate-titanate for actuators is that of Bi 0.50 Na 0.50 TiO₃ (BNT) based solid solutions. The pseudo-binary (1 - x )Bi 0.50 Na 0.50 TiO₃- x Ba 1 - y Ca y TiO₃ system has been proposed for high temperature capacitors and not yet fully explored as piezoelectric material. In this work, the solid solution with x = 0.06 and y = 0.10 was obtained by two different synthesis routes: solid state and Pechini, aiming at using reduced temperatures, both in synthesis (<800 °C) and sintering (<1150 °C), while maintaining appropriated piezoelectric performance. Crystal structure, ceramic grain size, and morphology depend on the synthesis route and were analyzed by X-ray diffraction, together with scanning and transmission electron microscopy. The effects of processing and ceramic microstructure on the structural, dielectric, ferroelectric, and piezoelectric properties were discussed in terms of a shift of the Morphotropic Phase Boundary, chemically induced by the synthesis route.

  17. Preparation and properties of a MnCo2O4 for ceramic interconnect of solid oxide fuel cell via glycine nitrate process

    NASA Astrophysics Data System (ADS)

    Yoon, Mi Young; Lee, Eun Jung; Song, Rak Hyun; Hwang, Hae Jin

    2011-12-01

    MnCo2O4 powder was prepared by a wet chemistry method using metal nitrates and glycine in an aqueous solution. The phase stability, sintering behavior, thermal expansion and electrical conductivity were examined to characterize powder suitability as an interconnect material in solid oxide fuel cells (SOFCs). X-ray diffraction indicated that the MnCo2O4 spinel synthesized by the glycine nitrate process was stable until 1100 °C and it was possible to obtain a fully densified single phase spinel. On the other hand, the MnCo2O4 synthesized by a solid state reaction decomposed into a cubic spinel and CoO after being sintered at 1100 °C. This might be associated with the reduction of Co3+ in the octahedral site of the cubic spinel phase. MnCo2O4 showed a thermal expansion coefficient comparable to that of other SOFCs components, as well as good electrical conductivity. Therefore, MnCo2O4 is a potential candidate for the ceramic interconnects in SOFCs, provided the phase instability under reducing environments can be improved.

  18. Liquid-solid surface phase transformation of fluorinated fullerene on monolayer tungsten diselenide

    NASA Astrophysics Data System (ADS)

    Song, Zhibo; Wang, Qixing; Li, Ming-Yang; Li, Lain-Jong; Zheng, Yu Jie; Wang, Zhuo; Lin, Tingting; Chi, Dongzhi; Ding, Zijing; Huang, Yu Li; Thye Shen Wee, Andrew

    2018-04-01

    Hybrid van der Waals heterostructures constructed by the integration of organic molecules and two-dimensional (2D) transition metal dichalcogenide (TMD) materials have useful tunable properties for flexible electronic devices. Due to the chemically inert and atomically smooth nature of the TMD surface, well-defined crystalline organic films form atomically sharp interfaces facilitating optimal device performance. Here, the surface phase transformation of the supramolecular packing structure of fluorinated fullerene (C60F48 ) on single-layer tungsten diselenide (WSe2) is revealed by low-temperature scanning tunneling microscopy, from thermally stable liquid to solid phases as the coverage increases. Statistical analysis of the intermolecular interaction potential reveals that the repulsive dipole-dipole interaction induced by interfacial charge transfer and substrate-mediated interactions play important roles in stabilizing the liquid C60F48 phases. Theoretical calculations further suggest that the dipole moment per C60F48 molecule varies with the surface molecule density, and the liquid-solid transformation could be understood from the perspective of the thermodynamic free energy for open systems. This study offers insights into the growth behavior at 2D organic/TMD hybrid heterointerfaces.

  19. Optimization of single crystals of solid electrolytes with tysonite-type structure (LaF3) for conductivity at 293 K: 2. Nonstoichiometric phases R 1- y M y F3- y ( R = La-Lu, Y; M = Sr, Ba)

    NASA Astrophysics Data System (ADS)

    Sorokin, N. I.; Sobolev, B. P.; Krivandina, E. A.; Zhmurova, Z. I.

    2015-01-01

    Single crystals of fluorine-conducting solid electrolytes R 1 - y Sr y F3 - y and R 1 - y Ba y F3 - y ( R = La-Lu, Y) with a tysonite-type structure (LaF3) have been optimized for room-temperature conductivity σ293 K. The optimization is based on high-temperature measurements of σ( T) in two-component nonstoichiometric phases R 1 - y M y F3 - y ( M = Sr, Ba) as a function of the MF2 content. Optimization for thermal stability is based on studying the phase diagrams of MF2- RF3 systems ( M = Sr, Ba) and the behavior of nonstoichiometric crystals upon heating when measuring temperature dependences σ( T). Single crystals of many studied R 1 - y Sr y F3 - y and R 1 - y Ba y F3 - y phases have σ293 K values large enough to use these materials in solid-state electrochemical devices (chemical sensors, fluorine-ion batteries, accumulators, etc.) operating at room temperature.

  20. BIOREMEDIATION USING THE LAND TREATMENT CONCEPT

    EPA Science Inventory

    This document is designed to be used by those who are involved with the use of land treatment technologies for the remediation of contaminated solid phase materials. In addition to a discussion of the basic processes which drive land treatment applications, the parameters involv...

  1. A Binary Solid-Liquid Phase Diagram Experiment Including Determination of Purity, Enthalpy of Fusion and True Melting Point.

    ERIC Educational Resources Information Center

    Meyer, Edwin F.; Meyer, Joseph A.

    1980-01-01

    Describes an experiment as an alternative to undergraduate experiments limited to high temperature metal systems or lower temperature systems involving objectionable or unstable materials. Lists six advantages of the experiment. (Author/JN)

  2. Headspace and direct immersion solid phase microextraction procedures for selenite determination in urine, saliva and milk by gas chromatography mass spectrometry.

    PubMed

    Kapsimali, D C; Zachariadis, G A

    2009-10-01

    Two solid phase microextraction modes were investigated and compared for their performance on the determination of selenites in various biological liquids like human urine and saliva and various types of milk. Using sodium tetraethylborate (NaBEt(4)) as ethylating reagent, selenites are converted in situ to volatile diethylselenides (DESe) in aqueous medium. The derivative is collected in situ by solid phase microextraction (SPME) using a silica fiber coated with poly(dimethylsiloxane) (PDMS) either from the headspace (HS-SPME) or directly from the liquid phase (LP-SPME) and finally determined by capillary GC/MS. Under optimum conditions of SPME, the GC separation was also optimized. Between the two examined microextraction techniques, direct immersion of the PDMS fiber in the liquid phase was proved less satisfactory. In contrast, the headspace procedure appears to be more efficient. The quantification of selenites was achieved in SIM mode with good analytical performance. A non-fat milk powder certified reference material was analyzed to evaluate the accuracy of the method. The overall precision of the method was ranged between 6.2% and 9.7%. Detection limits achieved were 0.05microgL(-1) for human urine, 0.08microgL(-1) for saliva and 0.03-0.06microgL(-1) in various milk matrices.

  3. Solid-phase extraction with the metal-organic framework MIL-101(Cr) combined with direct analysis in real time mass spectrometry for the fast analysis of triazine herbicides.

    PubMed

    Li, Xianjiang; Xing, Jiawei; Chang, Cuilan; Wang, Xin; Bai, Yu; Yan, Xiuping; Liu, Huwei

    2014-06-01

    MIL-101(Cr) is an excellent metal-organic framework with high surface area and nanoscale cavities, making it promising in solid-phase extraction. Herein, we used MIL-101(Cr) as a solid-phase extraction packing material combined with fast detection of direct analysis in real time mass spectrometry (DART-MS) for the analysis of triazine herbicides. After systematic optimization of the operation parameters, including the gas temperature of DART, the moving speed of the 1D platform, solvent for desorption, amount of MIL-101(Cr) extraction time, eluent volume and salt concentration, this method can realize the simultaneous detection of five kinds of triazine herbicides. The limits of detection were 0.1∼0.2 ng/mL and the linear ranges covered more than two orders of magnitude with the quantitation limits of 0.5∼1 ng/mL. Moreover, the developed method has been applied for the analysis of lake water samples and the recoveries for spiked analytes were in the range of 85∼110%. These results showed that solid-phase extraction with metal-organic frameworks is an efficient sample preparation approach for DART-MS analysis and could find more applications in environmental analysis. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Sintering of Lead-Free Piezoelectric Sodium Potassium Niobate Ceramics

    PubMed Central

    Malič, Barbara; Koruza, Jurij; Hreščak, Jitka; Bernard, Janez; Wang, Ke; Fisher, John G.; Benčan, Andreja

    2015-01-01

    The potassium sodium niobate, K0.5Na0.5NbO3, solid solution (KNN) is considered as one of the most promising, environment-friendly, lead-free candidates to replace highly efficient, lead-based piezoelectrics. Since the first reports of KNN, it has been recognized that obtaining phase-pure materials with a high density and a uniform, fine-grained microstructure is a major challenge. For this reason the present paper reviews the different methods for consolidating KNN ceramics. The difficulties involved in the solid-state synthesis of KNN powder, i.e., obtaining phase purity, the stoichiometry of the perovskite phase, and the chemical homogeneity, are discussed. The solid-state sintering of stoichiometric KNN is characterized by poor densification and an extremely narrow sintering-temperature range, which is close to the solidus temperature. A study of the initial sintering stage revealed that coarsening of the microstructure without densification contributes to a reduction of the driving force for sintering. The influences of the (K + Na)/Nb molar ratio, the presence of a liquid phase, chemical modifications (doping, complex solid solutions) and different atmospheres (i.e., defect chemistry) on the sintering are discussed. Special sintering techniques, such as pressure-assisted sintering and spark-plasma sintering, can be effective methods for enhancing the density of KNN ceramics. The sintering behavior of KNN is compared to that of a representative piezoelectric lead zirconate titanate (PZT). PMID:28793702

  5. On-line solid phase selective separation and preconcentration of Cd(II) by solid-phase extraction using carbon active modified with methyl thymol blue.

    PubMed

    Ensafi, Ali A; Ghaderi, Ali R

    2007-09-05

    An on-line flow system was used to develop a selective and efficient on-line sorbent extraction preconcentration system for cadmium. The method is based on adsorption of cadmium ions onto the activated carbon modified with methyl thymol blue. Then the adsorbed ions were washed using 0.5M HNO(3) and the eluent was used to determine the Cd(II) ions using flame atomic absorption spectrometry. The results obtained show that the modified activated carbon has the greatest adsorption capacity of 80 microg of Cd(II) per 1.0 g of the solid phase. The optimal pH value for the quantitative preconcentration was 9.0 and full desorption is achieved by using 0.5M HNO(3) solution. It is established that the solid phase can be used repeatedly without a considerable adsorption capacity loss. The detection limit was less than 1 ngmL(-1) Cd(II), with an enrichment factor of 1000. The calibration graph was linear in the range of 1-2000 ngmL(-1) Cd(II). The developed method has been applied to the determination of trace cadmium (II) in water samples and in the following reference materials: sewage sludge (CRM144R), and sea water (CASS.4) with satisfactory results. The accuracy was assessed through recovery experiments.

  6. Incorporating technetium in minerals and other solids: A review

    NASA Astrophysics Data System (ADS)

    Luksic, Steven A.; Riley, Brian J.; Schweiger, Michael; Hrma, Pavel

    2015-11-01

    Technetium (Tc) can be incorporated into a number of different solids including spinel, sodalite, rutile, tin dioxide, pyrochlore, perovskite, goethite, layered double hydroxides, cements, and alloys. Synthetic routes are possible for each of these phases, ranging from high-temperature ceramic sintering to ball-milling of constituent oxides. However, in practice, Tc has only been incorporated into solid materials by a limited number of the possible syntheses. A review of the diverse ways in which Tc-immobilizing materials can be made shows the wide range of options available. Special consideration is given to hypothetical application to the Hanford Tank Waste and Vitrification Plant, such as adding a Tc-bearing mineral to waste glass melter feed. A full survey of solid Tc waste forms, the common synthesis routes to those waste forms, and their potential for application to vitrification processes are presented. The use of tin dioxide or ferrite spinel precursors to reduce Tc(VII) out of solution and into a durable form are shown to be of especially high potential.

  7. Thermodynamic Model Formulations for Inhomogeneous Solids with Application to Non-isothermal Phase Field Modelling

    NASA Astrophysics Data System (ADS)

    Gladkov, Svyatoslav; Kochmann, Julian; Reese, Stefanie; Hütter, Markus; Svendsen, Bob

    2016-04-01

    The purpose of the current work is the comparison of thermodynamic model formulations for chemically and structurally inhomogeneous solids at finite deformation based on "standard" non-equilibrium thermodynamics [SNET: e. g. S. de Groot and P. Mazur, Non-equilibrium Thermodynamics, North Holland, 1962] and the general equation for non-equilibrium reversible-irreversible coupling (GENERIC) [H. C. Öttinger, Beyond Equilibrium Thermodynamics, Wiley Interscience, 2005]. In the process, non-isothermal generalizations of standard isothermal conservative [e. g. J. W. Cahn and J. E. Hilliard, Free energy of a non-uniform system. I. Interfacial energy. J. Chem. Phys. 28 (1958), 258-267] and non-conservative [e. g. S. M. Allen and J. W. Cahn, A macroscopic theory for antiphase boundary motion and its application to antiphase domain coarsening. Acta Metall. 27 (1979), 1085-1095; A. G. Khachaturyan, Theory of Structural Transformations in Solids, Wiley, New York, 1983] diffuse interface or "phase-field" models [e. g. P. C. Hohenberg and B. I. Halperin, Theory of dynamic critical phenomena, Rev. Modern Phys. 49 (1977), 435-479; N. Provatas and K. Elder, Phase Field Methods in Material Science and Engineering, Wiley-VCH, 2010.] for solids are obtained. The current treatment is consistent with, and includes, previous works [e. g. O. Penrose and P. C. Fife, Thermodynamically consistent models of phase-field type for the kinetics of phase transitions, Phys. D 43 (1990), 44-62; O. Penrose and P. C. Fife, On the relation between the standard phase-field model and a "thermodynamically consistent" phase-field model. Phys. D 69 (1993), 107-113] on non-isothermal systems as a special case. In the context of no-flux boundary conditions, the SNET- and GENERIC-based approaches are shown to be completely consistent with each other and result in equivalent temperature evolution relations.

  8. Multiphase Dynamics of Magma Oceans

    NASA Astrophysics Data System (ADS)

    Boukaré, Charles-Edouard; Ricard, Yanick; Parmentier, Edgar M.

    2017-04-01

    Since the earliest study of the Apollo lunar samples, the magma ocean hypothesis has received increasing consideration for explaining the early evolution of terrestrial planets. Giant impacts seem to be able to melt significantly large planets at the end of their accretion. The evolution of the resulting magma ocean would set the initial conditions (thermal and compositionnal structure) for subsequent long-term solid-state planet dynamics. However, magma ocean dynamics remains poorly understood. The major challenge relies on understanding interactions between the physical properties of materials (e.g., viscosity (at liquid or solid state), buoyancy) and the complex dynamics of an extremely vigorously convecting system. Such complexities might be neglected in cases where liquidus/adiabat interactions and density stratification leads to stable situations. However, interesting possibilities arise when exploring magma ocean dynamics in other regime. In the case of the Earth, recent studies have shown that the liquidus might intersect the adiabat at mid-mantle depth and/or that solids might be buoyant at deep mantle conditions. These results require the consideration of more sophisticated scenarios. For instance, how does bottom-up crystallization look with buoyant crystals? To understand this complex dynamics, we develop a multiphase phase numerical code that can handle simultaneously phase change, the convection in each phase and in the slurry, as well as the compaction or decompaction of the two phases. Although our code can only run in a limited parameter range (Rayleigh number, viscosity contrast between phases, Prandlt number), it provides a rich dynamics that illustrates what could have happened. For a given liquidus/adiabat configuration and density contrast between melt and solid, we explore magma ocean scenarios by varying the relative timescales of three first order processes: solid-liquid separation, thermo-chemical convective motions and magma ocean cooling.

  9. Tuning the electrocaloric enhancement near the morphotropic phase boundary in lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Le Goupil, Florian; McKinnon, Ruth; Koval, Vladimir; Viola, Giuseppe; Dunn, Steve; Berenov, Andrey; Yan, Haixue; Alford, Neil Mcn.

    2016-06-01

    The need for more energy-efficient and environmentally-friendly alternatives in the refrigeration industry to meet global emission targets has driven efforts towards materials with a potential for solid state cooling. Adiabatic depolarisation cooling, based on the electrocaloric effect (ECE), is a significant contender for efficient new solid state refrigeration techniques. Some of the highest ECE performances reported are found in compounds close to the morphotropic phase boundary (MPB). This relationship between performance and the MPB makes the ability to tune the position of the MPB an important challenge in electrocaloric research. Here, we report direct ECE measurements performed on MPB tuned NBT-06BT bulk ceramics with a combination of A-site substitutions. We successfully shift the MPB of these lead-free ceramics closer to room temperature, as required for solid state refrigeration, without loss of the criticality of the system and the associated ECE enhancement.

  10. Tuning the electrocaloric enhancement near the morphotropic phase boundary in lead-free ceramics

    PubMed Central

    Le Goupil, Florian; McKinnon, Ruth; Koval, Vladimir; Viola, Giuseppe; Dunn, Steve; Berenov, Andrey; Yan, Haixue; Alford, Neil McN.

    2016-01-01

    The need for more energy-efficient and environmentally-friendly alternatives in the refrigeration industry to meet global emission targets has driven efforts towards materials with a potential for solid state cooling. Adiabatic depolarisation cooling, based on the electrocaloric effect (ECE), is a significant contender for efficient new solid state refrigeration techniques. Some of the highest ECE performances reported are found in compounds close to the morphotropic phase boundary (MPB). This relationship between performance and the MPB makes the ability to tune the position of the MPB an important challenge in electrocaloric research. Here, we report direct ECE measurements performed on MPB tuned NBT-06BT bulk ceramics with a combination of A-site substitutions. We successfully shift the MPB of these lead-free ceramics closer to room temperature, as required for solid state refrigeration, without loss of the criticality of the system and the associated ECE enhancement. PMID:27312287

  11. One Step Combustion Synthesis Of YAG:Ce Phosphor For Solid State Lighting

    NASA Astrophysics Data System (ADS)

    Yadav, Pooja; Gupta, K. Vijay Kumar; Muley, Aarti; Joshi, C. P.; Moharil, S. V.

    2011-10-01

    YAG:Ce is an important phosphor having applications in various fields ranging from solid state lighting to scintillation detectors. YAG phosphors doped with activators are mainly synthesized by solid state reaction techniques that require high sintering temperatures (above 1500°C) to eliminate YAM and YAP phases. Though several soft chemical routes have been explored for synthesis of YAG, most of these methods are complex and phase pure materials are not obtained in one step, but prolonged annealing at temperatures around 1000 C or above becomes necessary. One step combustion synthesis of YAG:Ce3+ and related phosphors carried out at 500 C furnace temperature is reported here. Activation with Ce3+ could be achieved during the synthesis without taking recourse to any post-combustion thermal treatment. LEDs prepared from the combustion synthesized YAG:Ce3+, exhibited properties comparable to those produced from the commercial phosphor.

  12. Tuning the electrocaloric enhancement near the morphotropic phase boundary in lead-free ceramics.

    PubMed

    Le Goupil, Florian; McKinnon, Ruth; Koval, Vladimir; Viola, Giuseppe; Dunn, Steve; Berenov, Andrey; Yan, Haixue; Alford, Neil McN

    2016-06-17

    The need for more energy-efficient and environmentally-friendly alternatives in the refrigeration industry to meet global emission targets has driven efforts towards materials with a potential for solid state cooling. Adiabatic depolarisation cooling, based on the electrocaloric effect (ECE), is a significant contender for efficient new solid state refrigeration techniques. Some of the highest ECE performances reported are found in compounds close to the morphotropic phase boundary (MPB). This relationship between performance and the MPB makes the ability to tune the position of the MPB an important challenge in electrocaloric research. Here, we report direct ECE measurements performed on MPB tuned NBT-06BT bulk ceramics with a combination of A-site substitutions. We successfully shift the MPB of these lead-free ceramics closer to room temperature, as required for solid state refrigeration, without loss of the criticality of the system and the associated ECE enhancement.

  13. Phase stability and processing of strontium and magnesium doped lanthanum gallate

    NASA Astrophysics Data System (ADS)

    Zheng, Feng

    Fuel Cells are one of the most promising energy transformers with respect to ecological and environmental issues. Solid Oxide Fuel Cells (SOFC) are all solid-state devices. One of the challenges to improve a SOFC is to lower the operating temperature while maintaining or increasing its output voltage. Undoped LaGaO3 is an insulator, doping transforms it into an oxygen-ionic conductor. Sr and Mg doped LaGaO3 (LSGM) perovskite is a new oxygen-ionic conductor with higher conductivity than yttria-stabilized zirconia (YSZ). This material is a candidate for a wide variety of electrochemical devices. In order to realize this potential, the phase stability and processing of this material needs to be investigated in detail. In this study, a systematic investigation of the LSGM materials in terms of phase stability, phase transition, sintering, microstructure and electrical conductivity as functions of temperature, doping content and A/B cation ratio has been carried out. The generalized formula of the materials investigated is (La1--xSrx)A(Ga1--yMg y)BO3--delta. Optimized processing parameters have been obtained by investigating their impact on density change and microstructure. Consequently, a suitable compositional window of the LSGM perovskite has been identified for SOFC electrolyte applications. Based on detailed diffraction analysis, it is found that the undoped LaGaO3 takes on the orthorhombic (Pbnm) symmetry at room temperature. This structure changes to rhombohedral (R3c) at 147 +/- 2°C or changes to monoclinic (I2/a) when the doping level increases from 0.1 to 0.2 moles. We have optimized the compositional window to make the single perovskite phase with high oxygen ionic conductivity (x = 0.10 to 0.20 with A/B ratio between 0.98 to 1.02). The best processing condition, starting from glycine nitrate process (GNP) combustion synthesized ultra-fine LSGM powder, is sintering in air at 1500°C for 2 hours. The doped material has higher oxygen ionic conductivity than YSZ at all temperatures. In addition, based on the structure and phase relations, a high temperature phase diagram for this system has been proposed. Finally, a model has been proposed to account for the high ionic conductivity of this material and to explain the effect of the doping content and the stoichiometry on the ionic conductivity. (Abstract shortened by UMI.)

  14. On the roles of solid wall in the thermal analysis of micro heat pipes

    NASA Astrophysics Data System (ADS)

    Hung, Yew Mun

    Micro heat pipe is a small-scale passive heat transfer device of very high thermal conductance that uses phase change and circulation of its working fluid to transfer thermal energy. Different from conventional heat pipe, a micro heat pipe does not contain any wick structure. In this thesis, a one-dimensional, steady-state mathematical model of a single triangular micro heat pipe is developed, with the main purpose of establishing a series of analytical studies on the roles of the solid wall of micro heat pipes in conjunction with the characterization of the thermal performance under the effects of various design and operational parameters. The energy equation of the solid wall is solved analytically to obtain the temperature distribution. The liquid phase is coupled with the solid wall through the continuity of heat flux at their interface, and the continuity, momentum and energy equations of the liquid and vapour phases, together with the Young-Laplace equation for capillary pressure, are solve numerically to yield the heat and fluid flow characteristics of the micro heat pipe. By coupling this mathematical model with the phase-change interfacial resistance model, the relationships for the axial temperature distributions of the liquid and vapour phases throughout the longitudinal direction of a micro heat pipe are also formulated. Four major aspects associated with the operational performance of micro heat pipes are discussed. Firstly, the investigation of the effects of axial conduction in the solid wall reveals that the presence of the solid wall induces change in the phase-change heat transport of the working fluid besides facilitating axial heat conduction in the solid wall. The analysis also highlights the effects of the thickness and thermal conductivity of the solid wall on the axial temperature distribution of solid wall, in the wake of the effects of the axial heat conduction induced on the phase-change heat transport of the working fluid. Secondly, analysis on thermal performance and physical phenomena of an overloaded micro heat pipes incorporating the effects of axial conduction in the solid wall is carried out. The thermal effects of the solid material are investigated and it is observed that the behaviour of the solid wall temperature distribution varies drastically as the applied heat load exceeds the heat transport capacity. The abrupt change in the temperature profile of an overloaded micro heat pipe is of considerable practical significance in which the occurrence of dryout can be identified by physically measuring the solid wall temperatures along the axial direction. Thirdly, by taking into account the axial conduction in the solid wall, the effect of gravity on the thermal performance of an inclined micro heat pipe is explored. Attributed to the occurrence of dryout, an abrupt temperature rise is observed at the evaporator end when the micro heat pipe is negatively inclined. Therefore, the orientation of a micro heat pipe can be determined by physically measuring the solid wall temperature. Lastly, by coupling the heat transfer model of phase-change phenomena at the liquid-vapour interface, the model with axial conduction in the solid wall of the micro heat pipe is extended to predict the axial liquid and vapour temperature distributions of the working fluid, which is useful for the verification of certain assumptions made in the derivation of the mathematical model besides for analyzing the heat transfer characteristics of the evaporation process.

  15. Biological Testing of Solid Phase and Suspended Phase Dredged Material from Commencement Bay, Tacoma, Washington

    DTIC Science & Technology

    1983-04-01

    BAY, TACOMA, WASHINGTON PREPARED BY: FISHERIES RESEARCH INSTITUTE University of Washington DTIC C. A ELECTE JUL11 1985 DISTRIBUTIONSTATEMENT A...Nakatani 9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT. PROJECT, TASK Fisheries Research Institute AREA & WORK UNIT NUMBERS School of... Fisheries WH-10 University of Washington Seattle, Washington 98195 11. CONTROLLING OFFICE NAME AND ADDRESS 12. REPORT DATE US Army Corps of Engineers

  16. Particles at fluid-fluid interfaces: A new Navier-Stokes-Cahn-Hilliard surface- phase-field-crystal model.

    PubMed

    Aland, Sebastian; Lowengrub, John; Voigt, Axel

    2012-10-01

    Colloid particles that are partially wetted by two immiscible fluids can become confined to fluid-fluid interfaces. At sufficiently high volume fractions, the colloids may jam and the interface may crystallize. The fluids together with the interfacial colloids form an emulsion with interesting material properties and offer an important route to new soft materials. A promising approach to simulate these emulsions was presented in Aland et al. [Phys. Fluids 23, 062103 (2011)], where a Navier-Stokes-Cahn-Hilliard model for the macroscopic two-phase fluid system was combined with a surface phase-field-crystal model for the microscopic colloidal particles along the interface. Unfortunately this model leads to spurious velocities which require very fine spatial and temporal resolutions to accurately and stably simulate. In this paper we develop an improved Navier-Stokes-Cahn-Hilliard-surface phase-field-crystal model based on the principles of mass conservation and thermodynamic consistency. To validate our approach, we derive a sharp interface model and show agreement with the improved diffuse interface model. Using simple flow configurations, we show that the new model has much better properties and does not lead to spurious velocities. Finally, we demonstrate the solid-like behavior of the crystallized interface by simulating the fall of a solid ball through a colloid-laden multiphase fluid.

  17. Role of bond adaptability in the passivation of colloidal quantum dot solids.

    PubMed

    Thon, Susanna M; Ip, Alexander H; Voznyy, Oleksandr; Levina, Larissa; Kemp, Kyle W; Carey, Graham H; Masala, Silvia; Sargent, Edward H

    2013-09-24

    Colloidal quantum dot (CQD) solids are attractive materials for photovoltaic devices due to their low-cost solution-phase processing, high absorption cross sections, and their band gap tunability via the quantum size effect. Recent advances in CQD solar cell performance have relied on new surface passivation strategies. Specifically, cadmium cation passivation of surface chalcogen sites in PbS CQDs has been shown to contribute to lowered trap state densities and improved photovoltaic performance. Here we deploy a generalized solution-phase passivation strategy as a means to improving CQD surface management. We connect the effects of the choice of metal cation on solution-phase surface passivation, film-phase trap density of states, minority carrier mobility, and photovoltaic power conversion efficiency. We show that trap passivation and midgap density of states determine photovoltaic device performance and are strongly influenced by the choice of metal cation. Supported by density functional theory simulations, we propose a model for the role of cations, a picture wherein metals offering the shallowest electron affinities and the greatest adaptability in surface bonding configurations eliminate both deep and shallow traps effectively even in submonolayer amounts. This work illustrates the importance of materials choice in designing a flexible passivation strategy for optimum CQD device performance.

  18. Environmentally Friendly Method: Development and Application to Carbon Aerogel as Sorbent for Solid-Phase Extraction.

    PubMed

    Dong, Sheying; Huang, Guiqi; Su, Meiling; Huang, Tinglin

    2015-10-14

    We developed two simple, fast, and environmentally friendly methods using carbon aerogel (CA) and magnetic CA (mCA) materials as sorbents for micro-solid-phase extraction (μ-SPE) and magnetic solid-phase extraction (MSPE) techniques. The material performances such as adsorption isotherm, adsorption kinetics, and specific surface area were discussed by N2 adsorption-desorption isotherm measurements, ultraviolet and visible (UV-vis) spectrophotometry, scanning electron microscopy (SEM), and high resolution transmission electron microscopy (HR-TEM). The experimental results proved that the heterogeneities of CA and mCA were well modeled with the Freundlich isotherm model, and the sorption process well followed the pseudo-second-order rate equation. Moreover, plant growth regulators (PGRs) such as kinetin (6-KT), 6-benzylaminopurine (6-BA), 2,4-dichlorophenoxyacetic acid (2,4-D), and uniconazole (UN) in a reservoir raw water sample were selected as the evaluation of applicability for the proposed μ-SPE and MSPE techniques using high performance liquid chromatography (HPLC). The experimental conditions of two methods such as the amount of sorbent, extraction time, pH, salt concentration, and desorption conditions were studied. Under the optimized conditions, two extraction methods provided high recoveries (89-103%), low the limits of detection (LODs) (0.01-0.2 μg L(-1)), and satisfactory analytical features in terms of precision (relative standard deviation, RSD, 1.7-5.1%, n=3). This work demonstrates the feasibility and the potential of CA and mCA materials as sorbents for μ-SPE and MSPE techniques. Besides, it also could serve as a basis for future development of other functional CAs in pretreatment technology and make them valuable for analysis of pollutants in environmental applications.

  19. Dynamic interaction of two-phase debris flow with pyramidal defense structures: An optimal strategy to efficiently protecting the desired area

    NASA Astrophysics Data System (ADS)

    Kattel, Parameshwari; Kafle, Jeevan; Fischer, Jan-Thomas; Mergili, Martin; Tuladhar, Bhadra Man; Pudasaini, Shiva P.

    2017-04-01

    In this work we analyze the dynamic interaction of two phase debris flows with pyramidal obstacles. To simulate the dynamic interaction of two-phase debris flow (a mixture of solid particles and viscous fluid) with obstacles of different dimensions and orientations, we employ the general two-phase mass flow model (Pudasaini, 2012). The model consists of highly non-linear partial differential equations representing the mass and momentum conservations for both solid and fluid. Besides buoyancy, the model includes some dominant physical aspects of the debris flows such as generalized drag, virtual mass and non-Newtonian viscous stress as induced by the gradient of solid-volume-fraction. Simulations are performed with high-resolution numerical schemes to capture essential dynamics, including the strongly re-directed flow with multiple stream lines, mass arrest and debris-vacuum generation when the rapidly cascading debris mass suddenly encounters the obstacle. The solid and fluid phases show fundamentally different interactions with obstacles, flow spreading and dispersions, run-out dynamics, and deposition morphology. A forward-facing pyramid deflects the mass wider, and a rearward-facing pyramid arrests a portion of solid-mass at its front. Our basic study reveals that appropriately installed obstacles, their dimensions and orientations have a significant influence on the flow dynamics, material redistribution and redirection. The precise knowledge of the change in dynamics is of great importance for the optimal and effective protection of designated areas along the mountain slopes and the runout zones. Further important results are, that specific installations lead to redirect either solid, or fluid, or both, in the desired amounts and directions. The present method of the complex interactions of real two-phase mass flows with the obstacles may help us to construct defense structures and to design advanced and physics-based engineering solutions for the prevention and mitigation of natural hazards caused by geophysical mass flows. References: Pudasaini, S. P. (2012): A general two-phase debris flow model. J. Geophys. Res. 117, F03010, doi: 10.1029/ 2011JF002186.

  20. Multi-layer solid-phase extraction and evaporation-enrichment methods for polar organic chemicals from aqueous matrices.

    PubMed

    Köke, Niklas; Zahn, Daniel; Knepper, Thomas P; Frömel, Tobias

    2018-03-01

    Analysis of polar organic chemicals in the aquatic environment is exacerbated by the lack of suitable and widely applicable enrichment methods. In this work, we assessed the suitability of a novel combination of well-known solid-phase extraction (SPE) materials in one cartridge as well as an evaporation method and for the enrichment of 26 polar model substances (predominantly log D < 0) covering a broad range of physico-chemical properties in three different aqueous matrices. The multi-layer solid-phase extraction (mlSPE) and evaporation method were investigated for the recovery and matrix effects of the model substances and analyzed with hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS). In total, 65% of the model substances were amenable (> 10% recovery) to the mlSPE method with a mean recovery of 76% while 73% of the model substances were enriched with the evaporation method achieving a mean recovery of 78%. Target and non-target screening comparison of both methods with a frequently used reversed-phase SPE method utilizing "hydrophilic and lipophilic balanced" (HLB) material was performed. Target analysis showed that the mlSPE and evaporation method have pronounced advantages over the HLB method since the HLB material retained only 30% of the model substances. Non-target screening of a ground water sample with the investigated enrichment methods showed that the median retention time of all detected features on a HILIC system decreased in the order mlSPE (3641 features, median t R 9.7 min), evaporation (1391, 9.3 min), HLB (4414, 7.2 min), indicating a higher potential of the described methods to enrich polar analytes from water compared with HLB-SPE. Graphical abstract Schematic of the method evaluation (recovery and matrix effects) and method comparison (target and non-target analysis) of the two investigated enrichment methods for very polar chemicals in aqueousmatrices.

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