WorldWideScience

Sample records for unit density materials

  1. Recommended reference materials for realization of physicochemical properties density

    CERN Document Server

    Herington, E F G

    1976-01-01

    This book first presents the nomenclature and units used in the determination of densities of liquids and solids, followed by a general description of the apparatus and the methods used in the measurement of density, with particular reference to the pycnometric, hydrostatic weighing, magnetic float, and temperature flotation methods. The use of water as a density reference material is then explained, focusing on the isotopic composition of Standard Mean Ocean Water (SMOW) and the absolute density of SMOW as a function of temperature. Problems due to the effect of pressure and dissolved gases o

  2. Kernel density estimation using graphical processing unit

    Science.gov (United States)

    Sunarko, Su'ud, Zaki

    2015-09-01

    Kernel density estimation for particles distributed over a 2-dimensional space is calculated using a single graphical processing unit (GTX 660Ti GPU) and CUDA-C language. Parallel calculations are done for particles having bivariate normal distribution and by assigning calculations for equally-spaced node points to each scalar processor in the GPU. The number of particles, blocks and threads are varied to identify favorable configuration. Comparisons are obtained by performing the same calculation using 1, 2 and 4 processors on a 3.0 GHz CPU using MPICH 2.0 routines. Speedups attained with the GPU are in the range of 88 to 349 times compared the multiprocessor CPU. Blocks of 128 threads are found to be the optimum configuration for this case.

  3. Density functional theory and multiscale materials modeling

    Indian Academy of Sciences (India)

    Swapan K Ghosh

    2003-01-01

    One of the vital ingredients in the theoretical tools useful in materials modeling at all the length scales of interest is the concept of density. In the microscopic length scale, it is the electron density that has played a major role in providing a deeper understanding of chemical binding in atoms, molecules and solids. In the intermediate mesoscopic length scale, an appropriate picture of the equilibrium and dynamical processes has been obtained through the single particle number density of the constituent atoms or molecules. A wide class of problems involving nanomaterials, interfacial science and soft condensed matter has been addressed using the density based theoretical formalism as well as atomistic simulation in this regime. In the macroscopic length scale, however, matter is usually treated as a continuous medium and a description using local mass density, energy density and other related density functions has been found to be quite appropriate. A unique single unified theoretical framework that emerges through the density concept at these diverse length scales and is applicable to both quantum and classical systems is the so called density functional theory (DFT) which essentially provides a vehicle to project the many-particle picture to a single particle one. Thus, the central equation for quantum DFT is a one-particle Schrödinger-like Kohn–Sham equation, while the same for classical DFT consists of Boltzmann type distributions, both corresponding to a system of noninteracting particles in the field of a density-dependent effective potential. Selected illustrative applications of quantum DFT to microscopic modeling of intermolecular interaction and that of classical DFT to a mesoscopic modeling of soft condensed matter systems are presented.

  4. Novel negative mass density resonant metamaterial unit cell

    Energy Technology Data Exchange (ETDEWEB)

    Cselyuszka, Norbert, E-mail: cselyu@yahoo.com; Sečujski, Milan, E-mail: secujski@uns.ac.rs; Crnojević-Bengin, Vesna, E-mail: bengin@uns.ac.rs

    2015-01-02

    In this paper a novel resonant unit cell of one-dimensional acoustic metamaterials is presented, which exhibits negative effective mass density. We theoretically analyze the unit cell and develop a closed analytical formula for its effective mass density. Then we proceed to demonstrate left-handed propagation of acoustic waves using the proposed unit cell. Finally, we present its dual-band version, capable of operating at two independent frequencies. - Highlights: • A novel acoustic metamaterial unit cell provides Lorentz-type resonant effective mass density. • Analytical formula for effective mass density is derived. • Acoustic bandstop medium and left-handed metamaterial based on the novel unit cell are presented. • Modified version of the unit cell, operating at two independent frequencies, is proposed.

  5. Size-dependent density of nanoparticles and nanostructured materials

    Energy Technology Data Exchange (ETDEWEB)

    Nanda, Karuna Kar, E-mail: nanda@mrc.iisc.ernet.in [Materials Research Centre, Indian Institute of Science, Bangalore 12 (India)

    2012-10-01

    We discuss the size-dependent density of nanoparticles and nanostructured materials keeping the recent experimental results in mind. The density is predicted to increase with decreasing size for nanoparticles but it can decrease with size for nanostructured materials that corroborates the experimental results reported in the literature. -- Highlights: ► Density of nanoparticles depends mainly on the size-dependent lattice parameter. ► Density is predicted to increase with decreasing size for nanoparticles. ► Density decreases with size for nanostructured materials.

  6. Critical current densities in superconducting materials

    Indian Academy of Sciences (India)

    P Chaddah

    2003-02-01

    We discuss recent research in the area of critical current densities $(J_C)$ in superconductors. This shall cover recent work on newly discovered superconductors, as well as on the magnetic-field dependence of $J_C$.

  7. Density functional theory in materials science.

    Science.gov (United States)

    Neugebauer, Jörg; Hickel, Tilmann

    2013-09-01

    Materials science is a highly interdisciplinary field. It is devoted to the understanding of the relationship between (a) fundamental physical and chemical properties governing processes at the atomistic scale with (b) typically macroscopic properties required of materials in engineering applications. For many materials, this relationship is not only determined by chemical composition, but strongly governed by microstructure. The latter is a consequence of carefully selected process conditions (e.g., mechanical forming and annealing in metallurgy or epitaxial growth in semiconductor technology). A key task of computational materials science is to unravel the often hidden composition-structure-property relationships using computational techniques. The present paper does not aim to give a complete review of all aspects of materials science. Rather, we will present the key concepts underlying the computation of selected material properties and discuss the major classes of materials to which they are applied. Specifically, our focus will be on methods used to describe single or polycrystalline bulk materials of semiconductor, metal or ceramic form.

  8. MATERIAL COMPOSITIONS AND NUMBER DENSITIES FOR NEUTRONICS CALCULATIONS

    Energy Technology Data Exchange (ETDEWEB)

    D. A. Thomas

    1996-01-02

    The purpose of this analysis is to calculate the number densities and isotopic weight percentages of the standard materials to be used in the neutronics (criticality and radiation shielding) evaluations by the Waste Package Development Department. The objective of this analysis is to provide material number density information which can be referenced by future neutronics design analyses, such as for those supporting the Conceptual Design Report.

  9. Urinary density measurement and analysis methods in neonatal unit care

    Directory of Open Access Journals (Sweden)

    Maria Vera Lúcia Moreira Leitão Cardoso

    2013-09-01

    Full Text Available The objective was to assess urine collection methods through cotton in contact with genitalia and urinary collector to measure urinary density in newborns. This is a quantitative intervention study carried out in a neonatal unit of Fortaleza-CE, Brazil, in 2010. The sample consisted of 61 newborns randomly chosen to compose the study group. Most neonates were full term (31/50.8% males (33/54%. Data on urinary density measurement through the methods of cotton and collector presented statistically significant differences (p<0.05. The analysis of interquartile ranges between subgroups resulted in statistical differences between urinary collector/reagent strip (1005 and cotton/reagent strip (1010, however there was no difference between urinary collector/ refractometer (1008 and cotton/ refractometer. Therefore, further research should be conducted with larger sampling using methods investigated in this study and whenever possible, comparing urine density values to laboratory tests.

  10. United States Automotive Materials Partnership LLC (USAMP)

    Energy Technology Data Exchange (ETDEWEB)

    United States Automotive Materials Partnership

    2011-01-31

    The United States Automotive Materials Partnership LLC (USAMP) was formed in 1993 as a partnership between Chrysler Corporation, Ford Motor Company, and General Motors Corporation. Since then the U.S. Department of Energy (DOE) has supported its activities with funding and technical support. The mission of the USAMP is to conduct vehicle-oriented research and development in materials and materials processing to improve the competitiveness of the U.S. Auto Industry. Its specific goals are: (1) To conduct joint research to further the development of lightweight materials for improved automotive fuel economy; and (2) To work with the Federal government to explore opportunities for cooperative programs with the national laboratories, Federal agencies such as the DOE and universities. As a major component of the DOE's Office of FreedomCAR and Vehicle Technologies Program (FCVT) collaboration with the USAMP, the Automotive Lightweighting Materials (ALM) program focuses on the development and validation of advanced materials and manufacturing technologies to significantly reduce automotive vehicle body and chassis weight without compromising other attributes such as safety, performance, recyclability, and cost. The FCVT was announced in FY 2002 and implemented in FY 2003, as a successor of the Partnership for a New Generation of Vehicles (PNGV), largely addressed under the first Cooperative Agreement. This second USAMP Cooperative Agreement with the DOE has expanded a unique and valuable framework for collaboratively directing industry and government research efforts toward the development of technologies capable of solving important societal problems related to automobile transportation. USAMP efforts are conducted by the domestic automobile manufacturers, in collaboration with materials and manufacturing suppliers, national laboratories, universities, and other technology or trade organizations. These interactions provide a direct route for implementing newly

  11. Separation of colloidal two dimensional materials by density gradient ultracentrifugation

    Energy Technology Data Exchange (ETDEWEB)

    Kuang, Yun; Song, Sha [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Huang, Jinyang, E-mail: huangjy@mail.buct.edu.cn [Department of Mathematics, College of Science, Beijing University of Chemical Technology, Beijing 100029 (China); Sun, Xiaoming, E-mail: sunxm@mail.buct.edu.cn [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)

    2015-04-15

    Two-dimensional (2D) materials have been made through various approaches but obtaining monodispersed simply by synthesis optimization gained little success, which highlighted the need for introducing nanoseparation methods. Density gradient ultracentrifugation method has emerged as a versatile and scalable method for sorting colloidal 2D nanomaterials. Isopycnic separation was applied on thickness-dependent separation of graphene nanosheets. And rate-zonal separation, as a more versatile separation method, demonstrated its capability in sorting nanosheets of chemically modified single layered graphene, layered double hydroxide, and even metallic Ag. Establishing such density gradient ultracentrifugation method not only achieves monodispersed nanosheets and provides new opportunities for investigation on size dependent properties of 2D materials, but also makes the surface modification possible by introducing “reaction zones” during sedimentation of the colloids. - Graphical abstract: Two-dimensional (2D) materials have been made through various approaches but obtaining monodispersed simply by synthesis optimization gained little success, which highlighted the need for introducing nanoseparation methods. Density gradient ultracentrifugation method has emerged as a versatile and scalable method for sorting colloidal 2D nanomaterials according to their size of thickness difference. Establishing such density gradient ultracentrifugation method not only achieves monodispersed nanosheets and provides new opportunities for investigation on size dependent properties of 2D materials, but also makes the surface modification possible by introducing “reaction zones” during sedimentation of the colloids. - Highlights: • Density gradient ultracentrifugation was applied on size separation of 2D material. • Isopycnic separation was applied on separation of low density materials. • Rate-zonal separation was applied on separation of large density materials. • Size

  12. Molecular Design of Low-Density Multifunctional Hybrid Materials

    Science.gov (United States)

    2016-01-01

    Structure -Property Relationships of Hybrid Mixed Oxide Organic - Inorganic Films for Multilayer Adhesive Bonding”, MRS 2012 Spring Meeting, San Francisco...AVAILABILITY STATEMENT No distribution limitation. 13. SUPPLEMENTARY NOTES 14. ABSTRACT Low-density hybrid materials, which contain organic and... hybrid materials, which contain organic and inorganic molecular components, can be engineered over a wide range of length scales to exhibit unique

  13. Magnetocaloric Materials and the Optimization of Cooling Power Density

    Science.gov (United States)

    Wikus, Patrick; Canavan, Edgar; Heine, Sarah Trowbridge; Matsumoto, Koichi; Numazawa, Takenori

    2014-01-01

    The magnetocaloric effect is the thermal response of a material to an external magnetic field. This manuscript focuses on the physics and the properties of materials which are commonly used for magnetic refrigeration at cryogenic temperatures. After a brief overview of the magnetocaloric effect and associated thermodynamics, typical requirements on refrigerants are discussed from a standpoint of cooling power density optimization. Finally, a compilation of the most important properties of several common magnetocaloric materials is presented.

  14. United States Automotive Materials Partnership LLC (USAMP)

    Energy Technology Data Exchange (ETDEWEB)

    United States Automotive Materials Partnership

    2011-01-31

    The United States Automotive Materials Partnership LLC (USAMP) was formed in 1993 as a partnership between Chrysler Corporation, Ford Motor Company, and General Motors Corporation. Since then the U.S. Department of Energy (DOE) has supported its activities with funding and technical support. The mission of the USAMP is to conduct vehicle-oriented research and development in materials and materials processing to improve the competitiveness of the U.S. Auto Industry. Its specific goals are: (1) To conduct joint research to further the development of lightweight materials for improved automotive fuel economy; and (2) To work with the Federal government to explore opportunities for cooperative programs with the national laboratories, Federal agencies such as the DOE and universities. As a major component of the DOE's Office of FreedomCAR and Vehicle Technologies Program (FCVT) collaboration with the USAMP, the Automotive Lightweighting Materials (ALM) program focuses on the development and validation of advanced materials and manufacturing technologies to significantly reduce automotive vehicle body and chassis weight without compromising other attributes such as safety, performance, recyclability, and cost. The FCVT was announced in FY 2002 and implemented in FY 2003, as a successor of the Partnership for a New Generation of Vehicles (PNGV), largely addressed under the first Cooperative Agreement. This second USAMP Cooperative Agreement with the DOE has expanded a unique and valuable framework for collaboratively directing industry and government research efforts toward the development of technologies capable of solving important societal problems related to automobile transportation. USAMP efforts are conducted by the domestic automobile manufacturers, in collaboration with materials and manufacturing suppliers, national laboratories, universities, and other technology or trade organizations. These interactions provide a direct route for implementing newly

  15. Population densities of painted buntings in the southeastern United States

    Science.gov (United States)

    Meyers, J. Michael

    2011-01-01

    The eastern population trend of Passerina ciris (Painted Bunting) declined 3.5% annually during the first 30 yrs of the Breeding Bird Survey (BBS, 1966–1996). Recently, the US Fish and Wildlife Service listed Painted Buntings as a focal species. Surveys for this focal species for the next 10 yrs (BBS, 1997–2007), however, are too low (2 in young pine plantations to 42 per km2 in maritime shrub. Effective detection radii for habitats varied from 64 to 90 m and were slightly higher in developed than in undeveloped habitats. Distance sampling is recommended to determine densities of Painted Buntings; however, large sample sizes (70–100 detections/habitat type) are required to monitor Painted Bunting densities in most habitats in the Atlantic coastal region of the southeastern United States. Special attention should be given to maritime shrub habitats, which may be important to maintaining the Painted Bunting population in the southeastern US.

  16. High density data storage principle, technology, and materials

    CERN Document Server

    Zhu, Daoben

    2009-01-01

    The explosive increase in information and the miniaturization of electronic devices demand new recording technologies and materials that combine high density, fast response, long retention time and rewriting capability. As predicted, the current silicon-based computer circuits are reaching their physical limits. Further miniaturization of the electronic components and increase in data storage density are vital for the next generation of IT equipment such as ultra high-speed mobile computing, communication devices and sophisticated sensors. This original book presents a comprehensive introduction to the significant research achievements on high-density data storage from the aspects of recording mechanisms, materials and fabrication technologies, which are promising for overcoming the physical limits of current data storage systems. The book serves as an useful guide for the development of optimized materials, technologies and device structures for future information storage, and will lead readers to the fascin...

  17. The density matrix method in photonic bandgap and antiferromagnetic materials

    Science.gov (United States)

    Barrie, Scott B.

    In this thesis, a theory for dispersive polaritonic bandgap (DPBG) and photonic bandgap (PBG) materials is developed. An ensemble of multi-level nanoparticles, such as non-interacting two-, three- and four-level atoms doped in DPBG and PBG materials is considered. The optical properties of these materials such as spontaneous emission, line broadening, fluorescence and narrowing of the natural linewidth have been studied using the density matrix method. Numerical simulations for these properties have been performed for the DPBG materials SiC and InAs, and for a PBG material with a 20 percent gap-to-midgap ratio. When a three-level nanoparticle is doped into a DPBG material, it is predicted that one or two bound states exist when one or both resonance energies, respectively, lie in the bandgap. It is shown when a resonance energy lies below the bandgap, its spectral density peak weakens and broadens as the resonance energy increases to the lower band edge. For the first time it is predicted that when a nanoparticle's resonance energy lies above the bandgap, its spectral density peak weakens and broadens as the resonance energy increases. A relation is also found between spectral structure and gap-to-midgap ratios. The dressed states of a two-level atom doped into a DPBG material under the influence of an intense monochromatic laser field are examined. The splitting of the dressed state energies is calculated, and it is predicted that the splitting depends on the polariton density of states and the Rabi frequency of laser field. The fluoresence is also examined, and for the first time two distinct control processes are found for the transition from one peak to three peaks. It was previously known that the Rabi frequency controlled the Stark effect, but this thesis predicts that the local of the peak with respect to the optical bandgap can cause a transition from one to three peaks even with a weak Rabi frequency. The transient linewidth narrowing of PBG crystal

  18. Laser Propagation in Nanostructured Ultra-Low-Density Materials

    Energy Technology Data Exchange (ETDEWEB)

    Fournier, K. B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Colvin, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Yogo, A [Osaka Univ. (Japan). Inst. of Laser Engineering; Kemp, G. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Matsukuma, H. [Osaka Univ. (Japan). Inst. of Laser Engineering; Tanaka, N. [Osaka Univ. (Japan). Inst. of Laser Engineering; Zhang, Z. [Osaka Univ. (Japan). Inst. of Laser Engineering; Koga, K. [Osaka Univ. (Japan). Inst. of Laser Engineering; Tosaki, S. [Osaka Univ. (Japan). Inst. of Laser Engineering; Nishimura, H. [Osaka Univ. (Japan). Inst. of Laser Engineering

    2016-03-15

    The nanostructure of very-low-density aerogels (< 10 mg/cm3) affects the laser heating and propagation of the subsequent heat front. Simulations treat these materials as an atomistic medium without any structure differentiating between near-solid-density material and voids. Thus, simulations fail to predict the effects of the aerogel’s physical micro or nanostructure on the laser-matter interaction. We have designed an experiment using the GEKKO XII laser and ILE diagnostics to characterize the ionization-wave propagation and x-ray yield from aerogel and mass-matched gaseous targets as the laser passes through each. By design, the gas and aerogel targets will have identical densities and identical effective ionization states.

  19. Density Functional Theory and Materials Modeling at Atomistic Length Scales

    Directory of Open Access Journals (Sweden)

    Swapan K. Ghosh

    2002-04-01

    Full Text Available Abstract: We discuss the basic concepts of density functional theory (DFT as applied to materials modeling in the microscopic, mesoscopic and macroscopic length scales. The picture that emerges is that of a single unified framework for the study of both quantum and classical systems. While for quantum DFT, the central equation is a one-particle Schrodinger-like Kohn-Sham equation, the classical DFT consists of Boltzmann type distributions, both corresponding to a system of noninteracting particles in the field of a density-dependent effective potential, the exact functional form of which is unknown. One therefore approximates the exchange-correlation potential for quantum systems and the excess free energy density functional or the direct correlation functions for classical systems. Illustrative applications of quantum DFT to microscopic modeling of molecular interaction and that of classical DFT to a mesoscopic modeling of soft condensed matter systems are highlighted.

  20. Effective atomic numbers and electron density of dosimetric material

    Directory of Open Access Journals (Sweden)

    Kaginelli S

    2009-01-01

    Full Text Available A novel method for determination of mass attenuation coefficient of x-rays employing NaI (Tl detector system and radioactive sources is described.in this paper. A rigid geometry arrangement and gating of the spectrometer at FWHM position and selection of absorber foils are all done following detailed investigation, to minimize the effect of small angle scattering and multiple scattering on the mass attenuation coefficient, m/r, value. Firstly, for standardization purposes the mass attenuation coefficients of elemental foils such as Aluminum, Copper, Molybdenum, Tantalum and Lead are measured and then, this method is utilized for dosimetric interested material (sulfates. The experimental mass attenuation coefficient values are compared with the theoretical values to find good agreement between the theory and experiment within one to two per cent. The effective atomic numbers of the biological substitute material are calculated by sum rule and from the graph. The electron density of dosimetric material is calculated using the effective atomic number. The study has discussed in detail the attenuation coefficient, effective atomic number and electron density of dosimetric material/biological substitutes.

  1. Electromagnetic field energy density in homogeneous negative index materials.

    Science.gov (United States)

    Shivanand; Webb, Kevin J

    2012-05-07

    An exact separation of both electric and magnetic energies into stored and lost energies is shown to be possible in the special case when the wave impedance is independent of frequency. A general expression for the electromagnetic energy density in such a dispersive medium having a negative refractive index is shown to be accurate in comparison with numerical results. Using an example metamaterial response that provides a negative refractive index, it is shown that negative time-averaged stored energy can occur. The physical meaning of this negative energy is explained as the energy temporarily borrowed by the field from the material. This observation for negative index materials is of interest when approaching properties for a perfect lens. In the broader context, the observation of negative stored energy is of consequence in the study of dispersive materials.

  2. High power densities from high-temperature material interactions

    Energy Technology Data Exchange (ETDEWEB)

    Morris, J.F.

    1981-01-01

    Thermionic energy conversion (TEC) and metallic-fluid heat pipes (MFHPs) offer important and unique advantages in terrestrial and space energy processing. And they are well suited to serve together synergistically. TEC and MFHPs operate through working-fluid vaporization, condensation cycles that accept great thermal power densities at high temperatures. TEC and MFHPs have apparently simple, isolated performance mechanisms that are somewhat similar. And they also have obviously difficult, complected material problems that again are somewhat similar. Intensive investigation reveals that aspects of their operating cycles and material problems tend to merge: high-temperature material effects determine the level and lifetime of performance. Simplified equations verify the preceding statement for TEC and MFHPs. Material properties and interactions exert primary influences on operational effectiveness. And thermophysicochemical stabilities dictate operating temperatures which regulate the thermoemissive currents of TEC and the vaporization flow rates of MFHPs. Major high-temperature material problems of TEC and MFHPs have been solved. These solutions lead to productive, cost-effective applications of current TEC and MFHPs - and point to significant improvements with anticipated technological gains.

  3. Advanced Porous Coating for Low-Density Ceramic Insulation Materials

    Science.gov (United States)

    Leiser, Daniel B.; Churchward, Rex; Katvala, Victor; Stewart, David; Balter, Aliza

    1988-01-01

    The need for improved coatings on low-density reusable surface insulation (RSI) materials used on the space shuttle has stimulated research into developing tougher coatings. The processing of a new porous composite "coating" for RST called toughened unipiece fibrous insulation Is discussed. Characteristics including performance in a simulated high-speed atmospheric entry, morphological structure before and after this exposure, resistance to Impact, and thermal response to a typical heat pulse are described. It is shown that this coating has improved impact resistance while maintaining optical and thermal properties comparable to the previously available reaction-cured glass coating.

  4. Image density property of optical information recording microcapsule material

    Science.gov (United States)

    Lai, Weidong; Li, Xiaowei; Li, Xinzheng; Fu, Guangsheng

    2009-05-01

    The microcapsules can act as novel optical functional material in which the optical recording substance such as color-forming substance, photoinitiator and prepolymer are encapsulated. In this paper, the microcapsules with average particle diameter of 300nm are prepared with interfacial polymerization method. The optical responding character of the microcapsule is analyzed based on IR spectra and image density technique. Results show that the microcapsule material encapsulated prepolymer TMPTA and photoinitiator Irgacure-ITX, TPO has thermal phase-change at 140°C, at which the penetrability of the microcapsule has the highest efficiency. With the increase of exposure time, the reduction in absorption intensities of the prepolymer TMPTA are observed at 1635cm-1 of C=C stretching and 898cm-1 of C-H stretching on the C=C molecular bond. Such a result can be ascribed to the double bond cleavage process of the prepolymer TMPTA is initiated by the optical-exposed photoinitiator, and superpolymer network is formed. The image density contrast between the unexposed and exposed microcapsule is enhanced with exposure time increased.

  5. Teaching Materials Evaluation and Adaptation of a Unit

    Institute of Scientific and Technical Information of China (English)

    沈化

    2014-01-01

    Teaching materials are quite important for teachers and students. Students only pay attention to interesting materials which can be counted good. Teachers should adapt the materials if they want to make the learning really take place and make their teaching more effective. The teaching materials in Unit 7 Weather in 21st Century Practical College English Viewing, Listen-ing&Speaking I can be counted good. But it is not good enough and needs adapting to make it better.

  6. Microstructural characterization of pressed HMX material sets at differing densities

    Science.gov (United States)

    Molek, C. D.; Welle, E. J.; Wixom, R. R.; Ritchey, M. B.; Samuels, P.; Horie, Y.

    2017-01-01

    The detonation physics community has embraced the idea that initiation of high explosives (HE) proceeds from an ignition event through subsequent growth to steady detonation. A weakness of all the commonly used ignition and growth models is the microstructural characteristics of the HE are not explicitly incorporated in their ignition and growth terms. This is the case in spite of a demonstrated, but not well-understood, empirical link between particle morphology and initiation of HE. Morphological effects have been parametrically studied in many ways, the majority of efforts focus on establishing a tie between bulk powder metrics and initiation of the pressed beds. More recently, there has been a shift toward characterizing the microstructure of pressed beds in order to understand the underlying mechanisms governing initiation behavior. In this work, we have characterized the microstructures of two HMX classes pressed at three densities using ion bombardment techniques. We find more significant compaction associated with the larger crystalline material - Class 3 - than the smaller fluid energy milled material. The Class 3 material exhibits evidence of crystal cracking. Finally, we discuss this evidence and our attempt to correlate microstructural features to observed changes in continuum level initiation behavior.

  7. Density of Line Features in the Western United States

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Density of linear features, such as roads, power lines, telephone lines, and railroad tracks have been shown to influence synanthropic predator abundance patterns...

  8. Applications of density functional theory in materials science and engineering

    Science.gov (United States)

    Alvarado, Manuel, Jr.

    Density Functional Theory (DFT) is a powerful tool that can be used to model various systems in materials science. Our research applies DFT to two problems of interest. First, an organic/inorganic complex dye system known as a Mayan pigment is modeled to determine chemical binding sites, verifying each model with physical data such as UV/Vis spectra. Preliminary studies on palygorskite-based mayan pigments (mayacrom blue, mayacrom purple) show excellent agreement with experimental studies when using a dimer dye geometry binding with tetrahedrally-coordinated aluminum impurity sites in palygorksite. This approach is applied to a sepiolite-based organic/inorganic dye system using thioindigo attached to a tetrahedral aluminum impurity site with an additional aluminum impurity site in close proximity to the binding site. As a second application of DFT, various grain orientations in beta-Sn are modeled under imposed strains in order to calculate elastic properties of this system. These calculations are intended to clarify discrepancies in published, experimental crystal compliance values.

  9. United abominations: Density functional studies of heavy metal chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Schoendorff, George [Iowa State Univ., Ames, IA (United States)

    2012-01-01

    Carbonyl and nitrile addition to uranyl (UO22+) are studied. The competition between nitrile and water ligands in the formation of uranyl complexes is investigated. The possibility of hypercoordinated uranyl with acetone ligands is examined. Uranyl is studied with diactone alcohol ligands as a means to explain the apparent hypercoordinated uranyl. A discussion of the formation of mesityl oxide ligands is also included. A joint theory/experimental study of reactions of zwitterionic boratoiridium(I) complexes with oxazoline-based scorpionate ligands is reported. A computational study was done of the catalytic hydroamination/cyclization of aminoalkenes with zirconium-based catalysts. Techniques are surveyed for programming for graphical processing units (GPUs) using Fortran.

  10. Fair Verbal Behavior: A Protocol Materials Unit for Teachers.

    Science.gov (United States)

    Mullis, Ina V. S.

    This protocol materials unit, based on the interaction component of instruction, is designed to help prospective teachers better understand verbal behaviors as related to fair (positive feedback) and unfair (negative feedback) responses. Fair verbal behavior is defined as following a standard of equal treatment toward all students and as free from…

  11. Design of high energy density thermoelectric energy conversion unit by using FGM compliant pads

    CERN Document Server

    Kambe, M

    1999-01-01

    In order to provide increasingly large amounts of electrical power to space and terrestrial systems with a sufficiently high level of reliability at a reasonable cost, thermoelectric (TE) energy conversion system by using $9 functionally graded material (FGM) compliant pads has been focused. To achieve high thermal energy density in TE power conversion systems, conductively coupling the TE units to the hot and cold heat exchangers is the most effective $9 configuration. This is accomplished by two sets of FGM compliant pads. This design strategy provides (1) a high flux, direct conduction path to heat source and heat sink, (2) the structural flexibility to protect the cell from high $9 stress due to thermal expansion, (3) an extended durability by a simple FGM structure, and (4) manufacturing cost reduction by spark plasma sintering. High thermal energy density of ten times as much as conventional radioisotope $9 thermoelectric generator is expected. Manufacturing of Cu/Al/sub 2/O/sub 3//Cu symmetrical FGM co...

  12. Tensile Behavior of Low Density Thermally Bonded Nonwoven Material

    Directory of Open Access Journals (Sweden)

    Xiaonan Hou

    2009-06-01

    Full Text Available A discontinuous and non-uniform microstructure of alow-density thermally bonded nonwoven materialdisplays in a complicated and unstable tensilebehavior. This paper reports uniaxial tensile tests of alow density thermally bonded nonwoven toinvestigate the effect of the specimen size and shapefactor, as well as the cyclic tensile loading conditionsemployed to investigate the deformational behaviorand performance of the nonwoven at differentloading stages. The experimental data are comparedwith results of microscopic image analysis and FEmodels.

  13. The role of adequate reference materials in density measurements in hemodialysis

    Science.gov (United States)

    Furtado, A.; Moutinho, J.; Moura, S.; Oliveira, F.; Filipe, E.

    2015-02-01

    In hemodialysis, oscillation-type density meters are used to measure the density of the acid component of the dialysate solutions used in the treatment of kidney patients. An incorrect density determination of this solution used in hemodialysis treatments can cause several and adverse events to patients. Therefore, despite the Fresenius Medical Care (FME) tight control of the density meters calibration results, this study shows the benefits of mimic the matrix usually measured to produce suitable reference materials for the density meter calibrations.

  14. 75 FR 52069 - Hazardous Materials: Harmonization With the United Nations Recommendations, International...

    Science.gov (United States)

    2010-08-24

    .... Hazardous Materials: Harmonization With the United Nations Recommendations, International Maritime Dangerous... Materials: Harmonization With the United Nations Recommendations, International Maritime Dangerous Goods... the Safe Transport of Dangerous Goods by Air, and the United Nations Recommendations on the...

  15. Modelling density segregation in flowing bidisperse granular materials

    Science.gov (United States)

    Xiao, Hongyi; Umbanhowar, Paul B.; Ottino, Julio M.; Lueptow, Richard M.

    2016-07-01

    Preventing segregation in flowing granular mixtures is an ongoing challenge for industrial processes that involve the handling of bulk solids. A recent continuum-based modelling approach accurately predicts spatial concentration fields in a variety of flow geometries for mixtures varying in particle size. This approach captures the interplay between advection, diffusion and segregation using kinematic information obtained from experiments and/or discrete element method (DEM) simulations combined with an empirically determined relation for the segregation velocity. Here, we extend the model to include density-driven segregation, thereby validating the approach for the two important cases of practical interest. DEM simulations of density bidisperse flows of mono-sized particles in a quasi-two-dimensional-bounded heap were performed to determine the dependence of the density-driven segregation velocity on local shear rate and particle concentration. The model yields theoretical predictions of segregation patterns that quantitatively match the DEM simulations over a range of density ratios and flow rates. Matching experiments reproduce the segregation patterns and quantitative segregation profiles obtained in both the simulations and the model, thereby demonstrating that the modelling approach captures the essential physics of density-driven segregation in granular heap flow.

  16. Achieving tunable sensitivity in composite high-energy density materials

    Science.gov (United States)

    Kuklja, Maija M.; Tsyshevsky, Roman V.; Rashkeev, Sergey

    2017-01-01

    Laser irradiation provides a unique opportunity for selective, predictive, and controlled initiation of energetic materials. We propose a consistent micro-scale mechanism of photoexcitation at the interface, formed by a molecular energetic material and a metal oxide. A specific PETN-MgO model composite is used to illustrate and explain seemingly puzzling experiments on selective laser initiation of energetic materials, which reported that the presence of metal oxide additives triggered the photoinitiation by an unusually low energy. We suggest that PETN photodecomposition is catalyzed by oxygen vacancies (F0 centers) at the MgO surface. The proposed model suggests ways to tune sensitivity of energetic molecular materials to photoinitiation. Our quantum-chemical calculations suggest that the structural point defects (e.g., oxygen vacancies) strongly interact with the molecular material (e.g., adsorbed energetic molecules) by inducing a charge transfer at the interface and hence play an imperative role in governing both energy absorption and energy release in the system. Our approach and conclusions provide a solid basis for novel design of energetic interfaces with desired properties and offers a new perspective in the field of explosive materials and devices.

  17. Relative Density of Backfilled Soil Material around Monopiles for Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo; Frigaard, Peter

    2012-01-01

    The relative density of backfilled soil material around offshore monopiles is assessed through experimental testing in the Large Wave Channel (GWK) of the Coastal Research Centre (FZK) in Hannover. The relative density of the backfill material was found to vary between 65 and 80 %. The dependency...... of the relative density of backfill on the maximum pile bending moment is assessed through three-dimensional numerical modeling of a monopile foundation located at the offshore wind farm at Horns Reef, Denmark....

  18. Thixoinfiltration: a new approach to produce cellular and other low density metallic materials

    OpenAIRE

    M.H. Robert; A.F. Jorge; F. Gatamorta; R. R. SILVA

    2010-01-01

    Purpose: the work presents an innovative approach for the production of cellular metallic materials as well as low density metal matrix composites, by using thixoforming techniques; thixotropic semisolid metal is infiltrated into removable and non-removable space holder preforms. Different kinds of preforms are tested to obtain open cell material (sponges), syntactic foams and low density composites. Products are evaluated concerning relative density and mechanical behavior under compressive ...

  19. Density-Driven Currents and Deposition of Fine Materials

    DEFF Research Database (Denmark)

    Saremi, Sina

    Dredging is a key element in river, ports, coastal and offshore development. In general dredging is conducted for excavation at the river,lake or seabed, relocation of the material, maintenance of the navigation channels, mining underwater deposits, land reclamation or cleaning up the environment....... Dredging activities always make changes to the environment, such as alteration of the coastal or river morphology, currents and wave climates, and water quality. Such changes may be considered improving or degrading to the environment. The type of material being dredged, type of the dredging equipment...... and type of sediments change along and into the seabed. Variations in the material entering the hopper have been studied by assuming fluctuating inflow concentrations. The fluctuations impose a mean net change on the overflow concentrations. In the third part of this study, the above described CFD model...

  20. Materials for high-density electronic packaging and interconnection

    Science.gov (United States)

    1990-01-01

    Electronic packaging and interconnections are the elements that today limit the ultimate performance of advanced electronic systems. Materials in use today and those becoming available are critically examined to ascertain what actions are needed for U.S. industry to compete favorably in the world market for advanced electronics. Materials and processes are discussed in terms of the final properties achievable and systems design compatibility. Weak points in the domestic industrial capability, including technical, industrial philosophy, and political, are identified. Recommendations are presented for actions that could help U.S. industry regain its former leadership position in advanced semiconductor systems production.

  1. Progress in materials and technologies for ultrahigh density data storage

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    With the development of information superhighway, nanometer-scale data storage has been proposed and attracted great interest in recent years. This article reviews the research achievements in this field, and especially focuses on the materials for data recording by using an atomic force microscope (AFM) and scanning tunneling microscope (STM).

  2. A Method for Determining Bulk Density, Material Density, and Porosity of Melter Feed During Nuclear Waste Vitrification

    Energy Technology Data Exchange (ETDEWEB)

    Hilliard, Zachary J.; Hrma, Pavel R.

    2016-01-31

    Abstract Glass making efficiency largely depends on heat transfer to reacting glass batch (melter feed), which in turn is influenced by the bulk density (ρb) and porosity (Φ) as functions of temperature (T). Neither b(T) nor Φ(T) functions are readily accessible to direct measurement, but they can be determined based on monitoring the profile area of heated glass batch pellets and material density of batches quenched at various stages of conversion via pycnometry. For the determination of Φb, the bulk volume must be calculated as a function of temperature. This is done via a program constructed in MATLAB which takes an image of a pellet profile at a given temperature and calculates the volume of said pellet. The quenched density measured by pycnometry must be converted to the density at heat treatment temperature. This is done by taking into account the volume change due to thermal expansion/contraction.

  3. Materials Assessment of Components of the Extravehicular Mobility Unit

    Science.gov (United States)

    Olivas, John D.; Barrera, Enrique V.

    1996-01-01

    Current research interests for Extravehicular Mobility Unit (EMU) design and development are directed toward enhancements of the Shuttle EMU, implementation of the Mark 3 technology for Shuttle applications, and development of a next generation suit (the X suit) which has applications for prolonged space flight, longer extravehicular activity (EVA), and Moon and Mars missions. In this research project two principal components of the EMU were studied from the vantage point of the materials and their design criteria. An investigation of the flexible materials which make up the lay-up of materials for abrasion and tear protection, thermal insulation, pressure restrain, etc. was initiated. A central focus was on the thermal insulation. A vacuum apparatus for measuring the flexibility of the materials was built to access their durability in vacuum. Plans are to include a Residual Gas Analyzer on the vacuum chamber to measure volatiles during the durability testing. These tests will more accurately simulate space conditions and provide information which has not been available on the materials currently used on the EMU. Durability testing of the aluminized mylar with a nylon scrim showed that the material strength varied in the machine and transverse directions. Study of components of the EMU also included a study of the EMU Bearing Assemblies as to materials selection, engineered materials, use of coatings and flammability issues. A comprehensive analysis of the performance of the current design, which is a stainless steel assembly, was conducted and use of titanium alloys or engineered alloy systems and coatings was investigated. The friction and wear properties are of interest as are the general manufacturing costs. Recognizing that the bearing assembly is subject to an oxygen environment, all currently used materials as well as titanium and engineered alloys were evaluated as to their flammability. An aim of the project is to provide weight reduction since bearing

  4. [Reducing patient pressure sore incidence density in the pediatric surgical intensive care unit].

    Science.gov (United States)

    Huang, Wei-Chen; Chang, Shiow-Ru; Tang, Chi-Min

    2014-04-01

    Our unit recorded 21 cases of pressure sores from January 2011 to June 2011. The resulting pressure-sore incidence density of 0.74% exceeded the Taiwan Clinical Performance Indicator (TCPI) for medical centers (0.62%) as well as the mean incidence density for our unit (0.55%) during the same period in 2010. We developed this project to decrease the incidence density of pressure sores at our pediatric-surgical-intensive-care unit from 0.74% to 0.31%. Strategies implemented included: 1. providing on-the-job education; 2. providing bedside teaching; 3. developing a series of pictures to illustrate proper sitting, lying, and changing positions and the proper fixation of catheters; 4. implementing a reminder mechanism; 5. introducing pressure-preventing devices; 6. and establishing an audit team. Incidence density decreased from 0.74% (Jan. to Jun. 2011) to 0.18% (Mar. to Jul. 2012). We demonstrated that the developed improvement program effectively reduced the incidence density of pressure sores and increased the quality of nursing care.

  5. Examination of Poststroke Alteration in Motor Unit Firing Behavior Using High-Density Surface EMG Decomposition.

    Science.gov (United States)

    Li, Xiaoyan; Holobar, Ales; Gazzoni, Marco; Merletti, Roberto; Rymer, William Zev; Zhou, Ping

    2015-05-01

    Recent advances in high-density surface electromyogram (EMG) decomposition have made it a feasible task to discriminate single motor unit activity from surface EMG interference patterns, thus providing a noninvasive approach for examination of motor unit control properties. In the current study, we applied high-density surface EMG recording and decomposition techniques to assess motor unit firing behavior alterations poststroke. Surface EMG signals were collected using a 64-channel 2-D electrode array from the paretic and contralateral first dorsal interosseous (FDI) muscles of nine hemiparetic stroke subjects at different isometric discrete contraction levels between 2 to 10 N with a 2 N increment step. Motor unit firing rates were extracted through decomposition of the high-density surface EMG signals and compared between paretic and contralateral muscles. Across the nine tested subjects, paretic FDI muscles showed decreased motor unit firing rates compared with contralateral muscles at different contraction levels. Regression analysis indicated a linear relation between the mean motor unit firing rate and the muscle contraction level for both paretic and contralateral muscles (p < 0.001), with the former demonstrating a lower increment rate (0.32 pulses per second (pps)/N) compared with the latter (0.67 pps/N). The coefficient of variation (averaged over the contraction levels) of the motor unit firing rates for the paretic muscles (0.21 ± 0.012) was significantly higher than for the contralateral muscles (0.17 ± 0.014) (p < 0.05). This study provides direct evidence of motor unit firing behavior alterations poststroke using surface EMG, which can be an important factor contributing to hemiparetic muscle weakness.

  6. Nuclear isomers as ultra-high-energy-density materials

    Science.gov (United States)

    Poppe, C. H.; Weiss, M. S.; Anderson, J. D.

    1992-09-01

    A major energy advance could result if the enormous potential of nuclear energy storage could be tapped without the penalty of radioactive by-products. Recent research has uncovered a new method for nuclear energy storage with high energy density and no residual radioactivity. Nuclear isomers are metastable states of atomic nuclei which release their energy in a prompt burst of electromagnetic radiation; in many cases the product remaining after decay of isomer is stable and no activity is produced by the electromagnetic decay. Two kinds of nuclear isomers are known: spin isomers and shape isomers. The former lacks a release mechanism. Theory has predicted the existence of shape isomers in the mass range around mercury and gold where decay by fission is prohibited. Experiments on the existence of fissionless shape isomers have resulted in evidence for 27 different shape isomers in isotopes of mercury, lead, and thallium. Three potential candidates for release mechanisms have been identified to date: neutron catalysis (Hf- 178), laser-electron-nuclear coupling (Th-229), and Stark-shift-induced mixing (speculative). Ways of producing nonfissioning shape isomers are discussed.

  7. Supersonic Propagation of Heat Waves in Low Density Heavy Material

    Institute of Scientific and Technical Information of China (English)

    Jiang Shaoen; Zhang Wenhai; Yi Rongqing; Cui Yanli; Chen Jiusen; Xu Yan; Ding Yongkun; Lai Dongxian; Zheng Zhijian; Huang Yikiang; Li Jinghong; Sun Kexu; Hu Xin

    2005-01-01

    The propagation of a supersonic heat-wave through copper-doped foam with a density of 50 mg/cm3 was experimentally investigated. The wave is driven by 140 eV Holhraum radiations generated in a cylindrical gold cavity heated by a 2 k J, 1ns laser pulse (0.35 μm). The delayed breakout time of the radiation waves from the rear side of the foam is measured by a threechromatic streaked x-ray spectrometer (TCS) consisting of a set of three-imaging pinholes and an array of three transmission gratings coupled with an x-ray streak camera (XSC). With one shot,simultaneous measurements of the delays of the drive source and the radiation with two different energies (210 eV, 840 eV) through the foam have been made for the first time. The experimental results indicate that the time delays vary with photon energies. The radiation with an energy of 210 eV propagates at a lower velocity. The radiating heat wave propagates with a velocity that is larger than the sound speed. Using TGS, the transmitting spectrum was measured, and then lower limit of the optical depth which is more than 1, was obtained. The experimental data were in agreement with numerical simulations.

  8. 76 FR 82163 - Hazardous Materials: Harmonization With the United Nations Recommendations on the Transport of...

    Science.gov (United States)

    2011-12-30

    ... Hazardous Materials: Harmonization With the United Nations Recommendations on the Transport of Dangerous... United Nations Recommendations on the Transport of Dangerous Goods: Model Regulations (UN Model... and from the United States. In this document, PHMSA responds to administrative appeals,...

  9. Advanced Cathode Material For High Energy Density Lithium-Batteries Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced cathode materials having high red-ox potential and high specific capacity offer great promise to the development of high energy density lithium-based...

  10. Quantifying Density, Water Adsorption and Equilibration Properties of Wind Tunnel Materials

    Science.gov (United States)

    Yu, Xinting; Horst, Sarah; He, Chao; Bridges, Nathan; Burr, Devon M.; Sebree, Joshua

    2016-10-01

    Aeolian processes are found on various planetary bodies including Earth, Venus, Mars, Titan, Triton, Pluto, and Comet 67P. Wind tunnels can simulate aeolian processes under different planetary parameters, with the robustness of results relying on experimental conditions and understanding of experimental materials. Threshold wind speed, the minimum wind speed to initiate saltation, is one parameter that can be investigated in wind tunnels. Liquid water adsorbed on wind tunnel materials could greatly enhance the threshold wind speed by increasing the interparticle force, density, and effective size of particles. Previous studies have shown that this effect could increase the threshold by 100% by putting 0.3-0.6% of water into typical dry quartz sand (Fecan et al. 1998). In order to simulate the weight of particles on other planetary bodies where gravity is significantly lower than on Earth, low-density materials are used in planetary wind tunnels, including walnut shells, activated charcoal, iced tea, and instant coffee.We first quantified the densities for all wind tunnel materials using a pycnometer and updated the density for low-density materials (e.g., walnut shells have density of 1.4 g/cm3 instead of 1.1 g/cm3 in the literature (Greeley et al. 1980)). Then we present a set of measurements that quantify water adsorption for both low and high-density materials (sand, basalt, and chromite). We first measured the water content and equilibration timescales for the materials through gravimetric measurements. We found low-density materials tend to have much more water (>5%) compared to high-density materials ( 6 hrs) compared to high-density materials (10-50 minutes). Since only water adsorbed on the particle surface would change the interparticle force, we then separate the surface and internal water using thermo-gravimetric analysis, and found that >80% of the water is still on the surface. Thus we assume water adsorption for low-density materials could greatly

  11. 30 CFR 57.22606 - Explosive materials and blasting units (III mines).

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Explosive materials and blasting units (III... materials and blasting units (III mines). (a) Mine operators shall notify the appropriate MSHA District Manager of all nonapproved explosive materials and blasting units to be used prior to their use....

  12. Bulk Density Adjustment of Resin-Based Equivalent Material for Geomechanical Model Test

    Directory of Open Access Journals (Sweden)

    Pengxian Fan

    2015-01-01

    Full Text Available An equivalent material is of significance to the simulation of prototype rock in geomechanical model test. Researchers attempt to ensure that the bulk density of equivalent material is equal to that of prototype rock. In this work, barite sand was used to increase the bulk density of a resin-based equivalent material. The variation law of the bulk density was revealed in the simulation of a prototype rock of a different bulk density. Over 300 specimens were made for uniaxial compression test. Test results indicated that the substitution of quartz sand by barite sand had no apparent influence on the uniaxial compressive strength and elastic modulus of the specimens but can increase the bulk density, according to the proportional coarse aggregate content. An ideal linearity was found in the relationship between the barite sand substitution ratio and the bulk density. The relationship between the bulk density and the usage of coarse aggregate and barite sand was also presented. The test results provided an insight into the bulk density adjustment of resin-based equivalent materials.

  13. Effect of density on forward and upward smoldering combustion of cellulosic material

    Science.gov (United States)

    Veronica, Sherly; Putri, R. H.; Fitriani, F.; Ramadhan, M. L.; Riki, M.; Reynaldo, S.; Imran, F. A.; Nugroho, Yulianto S.

    2017-03-01

    Smoldering is a slow, flameless and the most persistent type of combustion. Wildland fire or ground fire is an example of smoldering combustion which has become one of the most important issue in Indonesia and no effective solution has been found to solve this phenomenon yet. The organic materials contained in peatland can potentially become a flammable fuel with the presence of a trigger for wildland fire. In this experimental work tobacco material was used to study smoldering phenomenon. The relation between material density with temperature distribution and mass loss rate are conducted in the experiment. The transmissivity of the smoke produced by the smoldering combustion will also be analyzed. Experiments are carried out for the material density ranging from 0.12 - 0.2 g/cm3. The result showed that smoldering combustion are affected by density, due to the allowance of airflow and heat propagation. The result showed that material bed with the lowest density of 0.12 g/cm3 has the slowest smoldering velocity and mass loss rate while the material bed with the highest density of 0.2 g/cm3 has the fastest smoldering velocity and mass loss rate. The smoke took a longer period time to reach the bed surface at higher bed density.

  14. An algorithm for noise correction of dual-energy computed tomography material density images.

    Science.gov (United States)

    Maia, Rafael Simon; Jacob, Christian; Hara, Amy K; Silva, Alvin C; Pavlicek, William; Ross, Mitchell J

    2015-01-01

    Dual-energy computed tomography (DECT) images can undergo a two-material decomposition process which results in two images containing material density information. Material density images obtained by that process result in images with increased pixel noise. Noise reduction in those images is desirable in order to improve image quality. A noise reduction algorithm for material density images was developed and tested. A three-level wavelet approach combined with the application of an anisotropic diffusion filter was used. During each level, the resulting noise maps are further processed, until the original resolution is reached and the final noise maps obtained. Our method works in image space and, therefore, can be applied to any type of material density images obtained from any DECT vendor. A quantitative evaluation of the noise-reduced images using the signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and 2D noise power spectrum was done to quantify the improvements. The noise reduction algorithm was applied to a set of images resulting in images with higher SNR and CNR than the raw density images obtained by the decomposition process. The average improvement in terms of SNR gain was about 49 % while CNR gain was about 52 %. The difference between the raw and filtered regions of interest mean values was far from reaching statistical significance (minimum [Formula: see text], average [Formula: see text]). We have demonstrated through a series of quantitative analyses that our novel noise reduction algorithm improves the image quality of DECT material density images.

  15. Degradation of cementitious materials associated with salstone disposal units

    Energy Technology Data Exchange (ETDEWEB)

    Flach, G. P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Smith, F. G. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2014-09-01

    The Saltstone facilities at the DOE Savannah River Site (SRS) stabilize and dispose of low-level radioactive salt solution originating from liquid waste storage tanks at the site. The Saltstone Production Facility (SPF) receives treated salt solution and mixes the aqueous waste with dry cement, blast furnace slag, and fly ash to form a grout slurry which is mechanically pumped into concrete disposal cells that compose the Saltstone Disposal Facility (SDF). The solidified grout is termed “saltstone”. Cementitious materials play a prominent role in the design and long-term performance of the SDF. The saltstone grout exhibits low permeability and diffusivity, and thus represents a physical barrier to waste release. The waste form is also reducing, which creates a chemical barrier to waste release for certain key radionuclides, notably Tc-99. Similarly, the concrete shell of a saltstone disposal unit (SDU) represents an additional physical and chemical barrier to radionuclide release to the environment. Together the waste form and the SDU compose a robust containment structure at the time of facility closure. However, the physical and chemical state of cementitious materials will evolve over time through a variety of phenomena, leading to degraded barrier performance over Performance Assessment (PA) timescales of thousands to tens of thousands of years. Previous studies of cementitious material degradation in the context of low-level waste disposal have identified sulfate attack, carbonation influenced steel corrosion, and decalcification (primary constituent leaching) as the primary chemical degradation phenomena of most relevance to SRS exposure conditions. In this study, degradation time scales for each of these three degradation phenomena are estimated for saltstone and concrete associated with each SDU type under conservative, nominal, and best estimate assumptions.

  16. Retrospective Assessment of Follicular Unit Density in Asian Men With Androgenetic Alopecia.

    Science.gov (United States)

    Ortega-Castillejos, Dell Kristie A; Pathomvanich, Damkerng

    2017-05-01

    Hair density, together with hair diameter has a tremendous impact on the cosmetic outcome of hair transplantation surgery. This retrospective study aims to assess the average number of follicular unit (FU) grafts in the donor area of Asian men with androgenetic alopecia. Seventy patients (ages 24-65 years old) with virgin scalp who had their first hair transplantation were included. During the harvesting procedure, a 2- to 3-cm-wide area of the donor site was shaved from ear to ear with 5 specific areas assigned as reference points for the study namely the central occipital area, left and right parietal and temporal areas. A video microscope was used to capture the field of each reference point. Follicular units in each area were counted and the number of 1-hair, 2-hair, and 3-hair follicular groupings was recorded. East and Southeast Asians had an average of 61.1 FU/cm (111.2 hairs/cm); West Asians had an average density of 63.6 FU/cm (126.8 hairs/cm); South Asians were noted to have an average density of 63.5 FU/cm (126.8 hairs/cm). Asian hair density has slight variations in the number of FU grafts in each donor area.

  17. Quantifying Slope Effects and Variations in Crater Density across a Single Geologic Unit

    Science.gov (United States)

    Meyer, Heather; Mahanti, Prasun; Robinson, Mark; Povilaitis, Reinhold

    2016-10-01

    Steep underlying slopes (>~5°) significantly increase the rate of degradation of craters [1-3]. As a result, the density of craters is less on steeper slopes for terrains of the same age [2, 4]. Thus, when age-dating a planetary surface, an area encompassing one geologic unit of constant low slope is chosen. However, many key geologic units, such as ejecta blankets, lack sufficient area of constant slope to derive robust age estimates. Therefore, accurate age-dating of such units requires an accurate understanding of the effects of slope on age estimates. This work seeks to determine if the observed trend of decreasing crater density with increasing slopes [2] holds for craters >1 km and to quantify the effect of slope for craters of this size, focusing on the effect of slopes over the kilometer scale. Our study focuses on the continuous ejecta of Orientale basin, where we measure craters >1 km excluding secondaries that occur as chains or clusters. Age-dating via crater density measurements relies on uniform cratering across a single geologic unit. In the case of ejecta blankets and other impact related surfaces, this assumption may not hold due to the formation of auto- secondary craters. As such, we use LRO WAC mosaics [5], crater size-frequency distributions, absolute age estimates, a 3 km slope map derived from the WAC GLD100 [6], and density maps for various crater size ranges to look for evidence of non-uniform cratering across the continuous ejecta of Orientale and to determine the effect of slope on crater density. Preliminary results suggest that crater density does decrease with increasing slope for craters >1 km in diameter though at a slower rate than for smaller craters.References: [1] Trask N. J. and Rowan L. C. (1967) Science 158, 1529-1535. [2] Basilevsky (1976) Proc. Lunar Sci. Conf. 7th, p. 1005-1020. [3] Pohn and Offield (1970) USGS Prof. Pap., 153-162. [4] Xiao et al. (2013) Earth and Planet. Sci. Lett., 376, pgs. 1-11. doi:10.1016/j.epsl.2013

  18. 77 FR 31274 - Hazardous Materials: Harmonization With the United Nations Recommendations on the Transport of...

    Science.gov (United States)

    2012-05-25

    ... 2137-AE83 Hazardous Materials: Harmonization With the United Nations Recommendations on the Transport... Goods Regulations (TDG Regulations), and the United Nations Recommendations on the Transport of... hazardous materials internationally, to, from, and within the United States. In this notice of...

  19. 77 FR 58173 - Proposed Extension of Existing Information Collection; Explosive Materials and Blasting Units...

    Science.gov (United States)

    2012-09-19

    ... Materials and Blasting Units (Pertains to Metal and Nonmetal Underground Mines Deemed To Be Gassy AGENCY... materials and blasting units as permissible for use in the mining industry. However, since there are no permissible explosives or blasting units available that have adequate blasting capacity for some metal...

  20. Density functional theory calculation on many-cores hybrid central processing unit-graphic processing unit architectures.

    Science.gov (United States)

    Genovese, Luigi; Ospici, Matthieu; Deutsch, Thierry; Méhaut, Jean-François; Neelov, Alexey; Goedecker, Stefan

    2009-07-21

    We present the implementation of a full electronic structure calculation code on a hybrid parallel architecture with graphic processing units (GPUs). This implementation is performed on a free software code based on Daubechies wavelets. Such code shows very good performances, systematic convergence properties, and an excellent efficiency on parallel computers. Our GPU-based acceleration fully preserves all these properties. In particular, the code is able to run on many cores which may or may not have a GPU associated, and thus on parallel and massive parallel hybrid machines. With double precision calculations, we may achieve considerable speedup, between a factor of 20 for some operations and a factor of 6 for the whole density functional theory code.

  1. A study on photon attenuation coefficients of different wood materials with different densities

    Science.gov (United States)

    Saritha, B.; Nageswara Rao, A. S.

    2015-12-01

    A study on the variation of linear attenuation coefficients with the densities of the wood samples is under taken. The soft wood and hard wood samples were collected from the forest area of Pakal in Warangal district. The linear and mass attenuation coefficients are measured using gamma ray spectrometry based on NaI (Tl) scintillation detector with energies of 662 KeV and 59.5 KeV respectively. The mass attenuation coefficient values measured from experiment and are compared with theoretical methods using XCOM program. The plots of density versus linear attenuation coefficient for different wood materials correspond to higher order polynomial are presented. It is observed that variation of linear attenuation coefficient depends on densities of materials. The Chloroxylon swietenia with more density has more linear attenuation coefficient at 59.5 KeV and 662 KeV. The variation in attenuation coefficient attributed to chemical composition of wood used in the experiment.

  2. [A study on image processing of digital radiography and measure of material micro-density directly].

    Science.gov (United States)

    Xia, Ping; Xu, Guang-Ming; Yin, Song; Liu, Sheng-Quan; Xu, Lian-Yuan

    2008-05-01

    Due to the high influents of the device itself and the surrounding environment, the background brightness of the digital radiography image is uniform and the image shows big noise. Therefore, in order to identify digital radiography images precisely, a further image processing is necessary. In this study, adaptive filtering, histogram equalization techniques and difference image methods were used for image processing and the results show that these techniques were useful to denoise, to intensify brightness and to rectify the background. In order to verify the feasibility of these techniques, poplar wood samples of heterogeneous material were used as experimental materials and Micro-density was measured directly by applying the linear relationship between grey scale of DR image and penetrate material density and contrasted with the result of microdensitometer. The results show these techniques were feasible and even gave a more precise measurement on wood micro-density compared to microdensitometer.

  3. Degradation Of Cementitious Materials Associated With Saltstone Disposal Units

    Energy Technology Data Exchange (ETDEWEB)

    Flach, G. P; Smith, F. G. III

    2013-03-19

    The Saltstone facilities at the DOE Savannah River Site (SRS) stabilize and dispose of low-level radioactive salt solution originating from liquid waste storage tanks at the site. The Saltstone Production Facility (SPF) receives treated salt solution and mixes the aqueous waste with dry cement, blast furnace slag, and fly ash to form a grout slurry which is mechanically pumped into concrete disposal cells that compose the Saltstone Disposal Facility (SDF). The solidified grout is termed “saltstone”. Cementitious materials play a prominent role in the design and long-term performance of the SDF. The saltstone grout exhibits low permeability and diffusivity, and thus represents a physical barrier to waste release. The waste form is also reducing, which creates a chemical barrier to waste release for certain key radionuclides, notably Tc-99. Similarly, the concrete shell of an SDF disposal unit (SDU) represents an additional physical and chemical barrier to radionuclide release to the environment. Together the waste form and the SDU compose a robust containment structure at the time of facility closure. However, the physical and chemical state of cementitious materials will evolve over time through a variety of phenomena, leading to degraded barrier performance over Performance Assessment (PA) timescales of thousands to tens of thousands of years. Previous studies of cementitious material degradation in the context of low-level waste disposal have identified sulfate attack, carbonation influenced steel corrosion, and decalcification (primary constituent leaching) as the primary chemical degradation phenomena of most relevance to SRS exposure conditions. In this study, degradation time scales for each of these three degradation phenomena are estimated for saltstone and concrete associated with each SDU type under conservative, nominal, and best estimate assumptions. The nominal value (NV) is an intermediate result that is more probable than the conservative

  4. van der Waals Density Functional Theory vdW-DFq for Semihard Materials

    Science.gov (United States)

    Peng, Qing; de, Suvranu

    There are a large number of materials with mild stiffness, which are not as soft as tissues and not as strong as metals. These semihard materials includes energetic materials, molecular crystals, layered materials, and van der Waals crystals. The integrity and mechanical stability are mainly determined by the interactions between instantaneously induced dipoles, the so called London dispersion force or van der Waals force. It is challenging to accurately model the structural and mechanical properties of these semihard materials in the frame of density functional theory where the non-local correlation functionals are not well known. Here we propose a van der Waals density functional named vdW-DFq to accurately model the density and geometry of semihard materials. Using β-cyclotetramethylene tetranitramine as a prototype, we adjust the enhancement factor of the exchange energy functional with generalized gradient approximations. We find this method to be simple and robust over a wide tuning range when calibrating the functional on-demand with experimental data. With a calibrated value q = 1 . 05 , the proposed vdW-DFq method shows good performance in predicting the geometries of 11 common energetic material molecular crystals and 3 typical layered van der Waals crystals. The authors would like to acknowledge the generous financial support from the Defense Threat Reduction Agency (DTRA) Grant # HDTRA1-13-1-0025.

  5. Theoretical characterization and design of small molecule donor material containing naphthodithiophene central unit for efficient organic solar cells.

    Science.gov (United States)

    Duan, Yu-Ai; Geng, Yun; Li, Hai-Bin; Jin, Jun-Ling; Wu, Yong; Su, Zhong-Min

    2013-07-15

    To seek for high-performance small molecule donor materials used in heterojunction solar cell, six acceptor-donor-acceptor small molecules based on naphtho[2,3-b:6,7-b']dithiophene (NDT) units with different acceptor units were designed and characterized using density functional theory and time-dependent density functional theory. Their geometries, electronic structures, photophysical, and charge transport properties have been scrutinized comparing with the reported donor material NDT(TDPP)2 (TDPP  =  thiophene-capped diketopyrrolopyrrole). The open circuit voltage (V(oc)), energetic driving force(ΔE(L-L)), and exciton binding energy (E(b)) were also provided to give an elementary understanding on their cell performance. The results reveal that the frontier molecular orbitals of 3-7 match well with the acceptor material PC61 BM, and compounds 3-5 were found to exhibit the comparable performances to 1 and show promising potential in organic solar cells. In particular, comparing with 1, system 7 with naphthobisthiadiazole acceptor unit displays broader absorption spectrum, higher V(oc), lower E(b), and similar carrier mobility. An in-depth insight into the nature of the involved excited states based on transition density matrix and charge density difference indicates that all S1 states are mainly intramolecular charge transfer states with the charge transfer from central NDT unit to bilateral acceptor units, and also imply that the exciton of 7 can be dissociated easily due to its large extent of the charge transfer. In a word, 7 maybe superior to 1 and may act as a promising donor candidate for organic solar cell. Copyright © 2013 Wiley Periodicals, Inc.

  6. Unit-Sphere Anisotropic Multiaxial Stochastic-Strength Model Probability Density Distribution for the Orientation of Critical Flaws

    Science.gov (United States)

    Nemeth, Noel

    2013-01-01

    Models that predict the failure probability of monolithic glass and ceramic components under multiaxial loading have been developed by authors such as Batdorf, Evans, and Matsuo. These "unit-sphere" failure models assume that the strength-controlling flaws are randomly oriented, noninteracting planar microcracks of specified geometry but of variable size. This report develops a formulation to describe the probability density distribution of the orientation of critical strength-controlling flaws that results from an applied load. This distribution is a function of the multiaxial stress state, the shear sensitivity of the flaws, the Weibull modulus, and the strength anisotropy. Examples are provided showing the predicted response on the unit sphere for various stress states for isotropic and transversely isotropic (anisotropic) materials--including the most probable orientation of critical flaws for offset uniaxial loads with strength anisotropy. The author anticipates that this information could be used to determine anisotropic stiffness degradation or anisotropic damage evolution for individual brittle (or quasi-brittle) composite material constituents within finite element or micromechanics-based software

  7. Computing the Density Matrix in Electronic Structure Theory on Graphics Processing Units.

    Science.gov (United States)

    Cawkwell, M J; Sanville, E J; Mniszewski, S M; Niklasson, Anders M N

    2012-11-13

    The self-consistent solution of a Schrödinger-like equation for the density matrix is a critical and computationally demanding step in quantum-based models of interatomic bonding. This step was tackled historically via the diagonalization of the Hamiltonian. We have investigated the performance and accuracy of the second-order spectral projection (SP2) algorithm for the computation of the density matrix via a recursive expansion of the Fermi operator in a series of generalized matrix-matrix multiplications. We demonstrate that owing to its simplicity, the SP2 algorithm [Niklasson, A. M. N. Phys. Rev. B2002, 66, 155115] is exceptionally well suited to implementation on graphics processing units (GPUs). The performance in double and single precision arithmetic of a hybrid GPU/central processing unit (CPU) and full GPU implementation of the SP2 algorithm exceed those of a CPU-only implementation of the SP2 algorithm and traditional matrix diagonalization when the dimensions of the matrices exceed about 2000 × 2000. Padding schemes for arrays allocated in the GPU memory that optimize the performance of the CUBLAS implementations of the level 3 BLAS DGEMM and SGEMM subroutines for generalized matrix-matrix multiplications are described in detail. The analysis of the relative performance of the hybrid CPU/GPU and full GPU implementations indicate that the transfer of arrays between the GPU and CPU constitutes only a small fraction of the total computation time. The errors measured in the self-consistent density matrices computed using the SP2 algorithm are generally smaller than those measured in matrices computed via diagonalization. Furthermore, the errors in the density matrices computed using the SP2 algorithm do not exhibit any dependence of system size, whereas the errors increase linearly with the number of orbitals when diagonalization is employed.

  8. Characteristic parameters of diffusive supersonic radiation transport in low density materials

    Institute of Scientific and Technical Information of China (English)

    Jiang Shao-En; Yang Jia-Min; Zheng Zhi-Jian; Ding Yong-Kun

    2007-01-01

    Diffusive heat waves play an important role in radiation hydrodynamics. In low density material, it may be possible that the radiative energy flux dominates the material energy flux and thus energy flow can be determined. In this paper by means of a simple algebraic method, the expressions characterizing the condition of diffusion approximation and supersonic transport of heat wave are found. In this case, the ratio of the radiative energy flux to the material energy flux is directly proportional to the product of Mach number M multiplied by optical depth τ. And it may also be expressed by radiation temperature heating material. The materiel density and length may be determined in order to aceve above-mentioned conditions when the driven temperature and duration are given.

  9. Density functional theory and beyond-opportunities for quantum methods in materials modeling semiconductor technology.

    Science.gov (United States)

    Shankar, Sadasivan; Simka, Harsono; Haverty, Michael

    2008-02-13

    In the semiconductor industry, the use of new materials has been increasing with the advent of nanotechnology. As critical dimensions decrease, and the number of materials increases, the interactions between heterogeneous materials themselves and processing increase in complexity. Traditionally, applications of ab initio techniques are confined to electronic structure and band gap calculations of bulk materials, which are then used in coarse-grained models such as mesoscopic and continuum models. Density functional theory is the most widely used ab initio technique that was successfully extended to several applications. This paper illustrates applications of density functional theory to semiconductor processes and proposes further opportunities for use of such techniques in process development.

  10. Density of loose-fill insulation material exposed to cyclic humidity conditions

    DEFF Research Database (Denmark)

    Rasmussen, Torben Valdbjørn

    the granulated loose-fill material is exposed to a climate that is characterised as cyclic humidity conditions (a constant temperature and a relative humidity alternating between two predetermined constant relative humidity levels). A better understanding of the behaviour of granulated loose-fill material...... is provided and a standardised method is proposed. This enables control of the settling and prediction of densities necessary to prevent settling. The Nordtest, Organisation for Testing in Scandinavia funded the Nordtest Projekt 1623-03....

  11. Ru/Al Multilayers Integrate Maximum Energy Density and Ductility for Reactive Materials

    OpenAIRE

    K. Woll; Bergamaschi, A; Avchachov, K.; Djurabekova, F.; Gier, S.; Pauly, C.; Leibenguth, P.; Wagner, C; Nordlund, K.; Mücklich, F

    2016-01-01

    Established and already commercialized energetic materials, such as those based on Ni/Al for joining, lack the adequate combination of high energy density and ductile reaction products. To join components, this combination is required for mechanically reliable bonds. In addition to the improvement of existing technologies, expansion into new fields of application can also be anticipated which triggers the search for improved materials. Here, we present a comprehensive characterization of the ...

  12. Range shift and dose perturbation with high-density materials in proton beam therapy

    Energy Technology Data Exchange (ETDEWEB)

    Nichiporov, D., E-mail: nichipor@indiana.edu [Indiana University Integrated Science and Technology Hall, 2401 Milo B. Sampson La, Bloomington, IN 47408-1398 (United States); Moskvin, V. [Indiana University School of Medicine, 535 Barnhill Dr., RT 041, Indianapolis, IN 46202 (United States); Indiana University Health Proton Therapy Center, 2425 Milo B. Sampson La, Bloomington, IN 47408 (United States); Fanelli, L. [Indiana University Health Proton Therapy Center, 2425 Milo B. Sampson La, Bloomington, IN 47408 (United States); Das, I.J. [Indiana University School of Medicine, 535 Barnhill Dr., RT 041, Indianapolis, IN 46202 (United States); Indiana University Health Proton Therapy Center, 2425 Milo B. Sampson La, Bloomington, IN 47408 (United States)

    2011-11-15

    Radiotherapy with proton beams requires accurate knowledge of the proton range. When materials with high atomic numbers (Z) and densities (e.g. prostheses or implants) are present in the patient, they give rise to pronounced uncertainties in computed tomography data and to large errors in proton range and dose calculations. A modified analytical expression is proposed for the observed range shift in water in the presence of a high-density material of known thickness and density. The expression was verified experimentally in a clinical beam with various thicknesses and materials in a water phantom, at several beam ranges and at different depths. Measurements were also made behind the medium-to-water interface to evaluate dose perturbation using a thin window parallel plate ion chamber. Primary particle fluence variations due to the range shift were studied in a separate experiment. The measured range shift was in good agreement ({+-}0.3 mm) with the analytical expression for most of the materials studied. A small, but consistent dependence of range shift on the energy of impinging protons was found. Dose perturbation factor in water downstream of the material is less than +5% for thicknesses up to 8 g/cm{sup 2}. The proposed analytical expression can be used in clinical situations to determine the range shift in patient caused by an implanted material. Dose perturbation in the presence of an implant is due to the changes in primary particle fluence resulting from several physical processes.

  13. Density functional studies of functionalized graphitic materials with late transition metals for oxygen reduction reactions

    DEFF Research Database (Denmark)

    Vallejo, Federico Calle; Martinez, Jose Ignacio; Rossmeisl, Jan

    2011-01-01

    ) at the cathode. In this contribution, on the basis of Density Functional Theory (DFT) calculations, we show that graphitic materials with active sites composed of 4 nitrogen atoms and transition metal atoms belonging to groups 7 to 9 in the periodic table are active towards ORR, and also towards Oxygen Evolution...

  14. Some considerations of organic materials for high density optical disk data storage

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The application possibilities of organic materials for high density optical disk data storage are discussed.Several points,such as physical and chemical stabilities,wavelength match and reversible property changes,which should be taken into consideration,are presented.

  15. Measuring the Density of Different Materials by Using the Collimated Fast Neutron Beam

    Energy Technology Data Exchange (ETDEWEB)

    Sudac, D.; Nad, K.; Orlic, Z.; Obhodas, J. [Rudjer Boskovic Institute, Bijenicka c. 54, 10000 Zagreb (Croatia); Valkovic, V. [Rudjer Boskovic Institute, Zagreb (Croatia); Kvinticka 62, Zagreb (Croatia)

    2015-07-01

    It was demonstrated in the previous work that various threat materials could be detected inside the sea going cargo container by measuring the three variables, carbon and oxygen concentration and density of investigated material. Density was determined by measuring transmitted neutrons, which is not always practical in terms of setting up the instrument geometry. In order to enable more geometry flexibility, we have investigated the possibility of using the scattered neutrons in cargo material identification. For that purpose, the densities of different materials were measured depending on the position of neutron detectors and neutron generator with respect to the target position. One neutron detector was put above the target, one behind and one in front of the target, above the neutron generator. It was shown that all three positions of neutron detectors can be successfully used to measure the target density, but only if the detected neutrons are successfully discriminated from the gamma rays. Although the associated alpha particle technique/associate particle imaging (API) was used to discriminate the neutrons from the gamma rays, it is believed that the same results would be obtained by using the pulse shape discrimination method. In that way API technique can be avoided and the neutron generator which produces much higher beam intensity than 10{sup 8} n/s can be used. (authors)

  16. Self-Expanded Clustering Algorithm Based on Density Units with Evaluation Feedback Section

    Institute of Scientific and Technical Information of China (English)

    YU Yongqian; ZHAO Xiangguo; CHEN Hengyue; WANG Bin; YU Ge; WANG Guoren

    2006-01-01

    This paper presents an effective clustering mode and a novel clustering result evaluating mode. Clustering mode has two limited integral parameters. Evaluating mode evaluates clustering results and gives each a mark. The higher mark the clustering result gains, the higher quality it has. By organizing two modes in different ways, we can build two clustering algorithms: SECDU(Self-Expanded Clustering Algorithm based on Density Units) and SECDUF(Self-Expanded Clustering Algorithm Based on Density Units with Evaluation Feedback Section). SECDU enumerates all value pairs of two parameters of clustering mode to process data set repeatedly and evaluates every clustering result by evaluating mode. Then SECDU output the clustering result that has the highest evaluating mark among all the ones. By applying "hill-climbing algorithm", SECDUF improves clustering efficiency greatly. Data sets that have different distribution features can be well adapted to both algorithms. SECDU and SECDUF can output high-quality clustering results. SECDUF tunes parameters of clustering mode automatically and no man's action involves through the whole process. In addition, SECDUF has a high clustering performance.

  17. Metal azides under pressure: An emerging class of high energy density materials

    Indian Academy of Sciences (India)

    G Vaitheeswaran; K Ramesh Babu

    2012-11-01

    Metal azides are well-known for their explosive properties such as detonation or deflagration. As chemically pure sources of nitrogen, alkali metal azides under high pressure have the ability to form polymeric nitrogen, an ultimate green high energy density material with energy density three times greater than that of known high energetic materials. With this motive, in this present work, we try to address the high-pressure behaviour of LiN3 and KN3 by means of density functional calculations. All the calculations are performed with the inclusion of van derWaals interactions at semi empirical level, as these materials are typical molecular solids. We found that both LiN3 and KN3 are structurally stable up to the studied pressure range of 60 GPa and 16 GPa, respectively. At ambient conditions both the materials are insulators with a gap of 3.48 eV (LiN3) and 4.08 eV (KN3) and as pressure increases the band gap decreases and show semiconducting nature at high pressures.We also found that the compressibility of both the crystals is anisotropic which is in good agreement with experiment. Our theoretical study proved that the materials under study may have the ability to form polymeric nitrogen because of the decrease in interazide ion distance and possible overlapping of N atomic orbitals.

  18. α MnMoO₄/graphene hybrid composite: high energy density supercapacitor electrode material.

    Science.gov (United States)

    Ghosh, Debasis; Giri, Soumen; Moniruzzaman, Md; Basu, Tanya; Mandal, Manas; Das, Chapal Kumar

    2014-07-28

    A unique and cost effective hydrothermal procedure has been carried out for the synthesis of hexahedron shaped α MnMoO4 and its hybrid composite with graphene using three different weight percentages of graphene. Characterization techniques, such as XRD, Raman and FTIR analysis, established the phase and formation of the composite. The electrochemical characterization of the pseudocapacitive MnMoO4 and the MnMoO4/graphene composites in 1 M Na2SO4 displayed highest specific capacitances of 234 F g(-1) and 364 F g(-1), respectively at a current density of 2 A g(-1). Unlike many other pseudocapacitive electrode materials our prepared materials responded in a wide range of working potentials of (-)1 V to (+)1 V, which indeed resulted in a high energy density without substantial loss of power density. The highest energy densities of 130 Wh kg(-1) and 202.2 Wh kg(-1) were achieved, respectively for the MnMoO4 and the MnMoO4/graphene composite at a constant power delivery rate of 2000 W kg(-1). The synergistic effect of the graphene with the pseudocapacitive MnMoO4 caused an increased cycle stability of 88% specific capacitance retention after 1000 consecutive charge discharge cycles at 8 A g(-1) constant current density, which was higher than the virgin MnMoO4 with 84% specific capacitance retention.

  19. Progress in High Power Density SOFC Material Development for Aerospace Applications

    Science.gov (United States)

    Cable, Thomas L.; Sofie, Stephen W.; Setlock, John A.; Misra, Ajay K.

    2004-01-01

    Solid oxide fuel cell (SOFC) systems for aircraft applications require order of magnitude increase in specific power density and long life under aircraft operating conditions. Advanced SOFC materials and fabrication processes are being developed at NASA GRC to increase specific power density and durability of SOFC cell and stack. Initial research efforts for increasing specific power density are directed toward increasing the operating temperature for the SOFC system and reducing the weight of the stack. While significant research is underway to develop anode supported SOFC system operating at temperatures in the range of 650 - 850 C for ground power generation applications, such temperatures may not yield the power densities required for aircraft applications. For electrode-supported cells, SOFC stacks with power densities greater than 1.0 W/sq cm are favorable at temperatures in excess of 900 C. The performance of various commercial and developmental anode supported cells is currently being evaluated in the temperature range of 900 to 1000 C to assess the performance gains and materials reliability. The results from these studies will be presented. Since metal interconnects developed for lower temperature operation are not practical at these high temperatures, advanced perovskite based ceramic interconnects with high electronic conductivity and lower sintering temperatures are being developed. Another option for increasing specific power density of SOFC stacks is to decrease the stack weight. Since the interconnect contributes to a significant portion of the stack weight, considerable weight benefits can be derived by decreasing its thickness. Eliminating the gas channels in the interconnect by engineering the pore structure in both anode and cathode can offer significant reduction in thickness of the ceramic interconnect material. New solid oxide fuel cells are being developed with porous engineered electrode supported structures with a 10 - 20 micron thin

  20. Expancel Foams: Fabrication and Characterization of a New Reduced Density Cellular Material for Structural Applications

    Energy Technology Data Exchange (ETDEWEB)

    L. Whinnery; S. Goods; B. Even

    2000-08-01

    This study was initiated to produce a low-density centering medium for use in experiments investigating the response of materials to shock-loading. While the main drivers for material selection were homogeneity, dimensional stability, performance and cost, other secondary requirements included fine cell size, the ability to manufacture 5--10 cm-sized parts and an extremely compressed development time. The authors chose a non-traditional methodology using a hollow, expandable, polymeric microballoon material system called Expancel{reg_sign}. These microballoons are made from a copolymer of polyacrylonitrile (PAN) and polymethacrylonitrile (PMAN) and use iso-pentane as the blowing agent. The average diameter (by volume) of the unexpanded powder is approximately 13 {micro}m, while the average of the expanded powder is 35--55 {micro}m, with a few large microballoons approaching 150--200 p.m. A processing method was developed that established a pre-mixed combination of unexpanded and expanded Expancel at a ratio such that the tap (or vibration) density of the mixed powders was the same as that desired of the final part. Upon heating above the tack temperature of the polymer, this zero-rise approach allowed only expansion of the unexpanded powder to fill the interstices between the pre-expanded balloons. The mechanical action of the expanding powder combined with the elevated processing temperature yielded flee-standing and mechanically robust parts. Although mechanical properties of these foams were not a key performance requirement, the data allowed for the determination of the best temperature to heat the samples. Processing the foam at higher temperatures enhanced both modulus and strength. The maximum allowable temperature was limited by dimensional stability and shrinkback considerations. Tomographic analysis of foam billets revealed very flat density profiles. Parts of any density between the low density expanded powder (approximately 0.013 g/cm{sup 3}) and the

  1. Isotope-specific detection of low density materials with mono-energetic (gamma)-rays

    Energy Technology Data Exchange (ETDEWEB)

    Albert, F; Anderson, S G; Gibson, D J; Hagmann, C A; Johnson, M S; Messerly, M J; Semenov, V A; Shverdin, M Y; Tremaine, A M; Hartemann, F V; Siders, C W; McNabb, D P; Barty, C J

    2009-03-16

    The first demonstration of isotope-specific detection of a low-Z, low density object, shielded by a high-Z and high density material using mono-energetic gamma-rays is reported. Isotope-specific detection of LiH shielded by Pb and Al is accomplished using the nuclear resonance fluorescence line of {sup 7}Li at 0.478 MeV. Resonant photons are produced via laser-based Compton scattering. The detection techniques are general and the confidence level obtained is shown to be superior to that yielded by conventional x-ray/{gamma}-ray techniques in these situations.

  2. 78 FR 1101 - Hazardous Materials: Harmonization With the United Nations Recommendations on the Transport of...

    Science.gov (United States)

    2013-01-07

    ... 178 RIN 2137-AE83 Hazardous Materials: Harmonization With the United Nations Recommendations on the... Regulations), and the United Nations Recommendations on the Transport of Dangerous Goods: Model Regulations... a Department of Transportation (DOT) or United Nations (UN) standard packaging. Most...

  3. Ru/Al Multilayers Integrate Maximum Energy Density and Ductility for Reactive Materials.

    Science.gov (United States)

    Woll, K; Bergamaschi, A; Avchachov, K; Djurabekova, F; Gier, S; Pauly, C; Leibenguth, P; Wagner, C; Nordlund, K; Mücklich, F

    2016-01-01

    Established and already commercialized energetic materials, such as those based on Ni/Al for joining, lack the adequate combination of high energy density and ductile reaction products. To join components, this combination is required for mechanically reliable bonds. In addition to the improvement of existing technologies, expansion into new fields of application can also be anticipated which triggers the search for improved materials. Here, we present a comprehensive characterization of the key parameters that enables us to classify the Ru/Al system as new reactive material among other energetic systems. We finally found that Ru/Al exhibits the unusual integration of high energy density and ductility. For example, we measured reaction front velocities up to 10.9 (± 0.33) ms(-1) and peak reaction temperatures of about 2000 °C indicating the elevated energy density. To our knowledge, such high temperatures have never been reported in experiments for metallic multilayers. In situ experiments show the synthesis of a single-phase B2-RuAl microstructure ensuring improved ductility. Molecular dynamics simulations corroborate the transformation behavior to RuAl. This study fundamentally characterizes a Ru/Al system and demonstrates its enhanced properties fulfilling the identification requirements of a novel nanoscaled energetic material.

  4. Tracking motor units longitudinally across experimental sessions with high‐density surface electromyography

    Science.gov (United States)

    Martinez‐Valdes, E.; Negro, F.; Laine, C. M.; Falla, D.; Mayer, F.

    2017-01-01

    Key points Classic motor unit (MU) recording and analysis methods do not allow the same MUs to be tracked across different experimental sessions, and therefore, there is limited experimental evidence on the adjustments in MU properties following training or during the progression of neuromuscular disorders.We propose a new processing method to track the same MUs across experimental sessions (separated by weeks) by using high‐density surface electromyography.The application of the proposed method in two experiments showed that individual MUs can be identified reliably in measurements separated by weeks and that changes in properties of the tracked MUs across experimental sessions can be identified with high sensitivity.These results indicate that the behaviour and properties of the same MUs can be monitored across multiple testing sessions.The proposed method opens new possibilities in the understanding of adjustments in motor unit properties due to training interventions or the progression of pathologies. Abstract A new method is proposed for tracking individual motor units (MUs) across multiple experimental sessions on different days. The technique is based on a novel decomposition approach for high‐density surface electromyography and was tested with two experimental studies for reliability and sensitivity. Experiment I (reliability): ten participants performed isometric knee extensions at 10, 30, 50 and 70% of their maximum voluntary contraction (MVC) force in three sessions, each separated by 1 week. Experiment II (sensitivity): seven participants performed 2 weeks of endurance training (cycling) and were tested pre–post intervention during isometric knee extensions at 10 and 30% MVC. The reliability (Experiment I) and sensitivity (Experiment II) of the measured MU properties were compared for the MUs tracked across sessions, with respect to all MUs identified in each session. In Experiment I, on average 38.3% and 40.1% of the identified MUs could be

  5. Spatial association between dissection density and environmental factors over the entire conterminous United States

    Science.gov (United States)

    Luo, Wei; Jasiewicz, Jaroslaw; Stepinski, Tomasz; Wang, Jinfeng; Xu, Chengdong; Cang, Xuezhi

    2016-01-01

    Previous studies of land dissection density (D) often find contradictory results regarding factors controlling its spatial variation. We hypothesize that the dominant controlling factors (and the interactions between them) vary from region to region due to differences in each region's local characteristics and geologic history. We test this hypothesis by applying a geographical detector method to eight physiographic divisions of the conterminous United States and identify the dominant factor(s) in each. The geographical detector method computes the power of determinant (q) that quantitatively measures the affinity between the factor considered and D. Results show that the factor (or factor combination) with the largest q value is different for physiographic regions with different characteristics and geologic histories. For example, lithology dominates in mountainous regions, curvature dominates in plains, and glaciation dominates in previously glaciated areas. The geographical detector method offers an objective framework for revealing factors controlling Earth surface processes.

  6. A high speed compact microwave interferometer for density fluctuation measurements in Sino-UNIted Spherical Tokamak

    Science.gov (United States)

    Zhong, H.; Tan, Y.; Liu, Y. Q.; Xie, H. Q.; Gao, Z.

    2016-11-01

    A single-channel 3 mm interferometer has been developed for plasma density diagnostics in the Sino-UNIted Spherical Tokamak (SUNIST). The extremely compact microwave interferometer utilizes one corrugated feed horn antenna for both emitting and receiving the microwave. The beam path lies on the equatorial plane so the system would not suffer from beam path deflection problems due to the symmetry of the cross section. A focusing lens group and an oblique vacuum window are carefully designed to boost the signal to noise ratio, which allows this system to show good performance even with the small-diameter central column itself as a reflector, without a concave mirror. The whole system discards the reference leg for maximum compactness, which is particularly suitable for the small-sized tokamak. An auto-correcting algorithm is developed to calculate the phase evolution, and the result displays good phase stability of the whole system. The intermediate frequency is adjustable and can reach its full potential of 2 MHz for best temporal resolution. Multiple measurements during ohmic discharges proved the interferometer's capability to track typical density fluctuations in SUNIST, which enables this system to be utilized in the study of MHD activities.

  7. Relationship of Terminal Duct Lobular Unit Involution of the Breast with Area and Volume Mammographic Densities

    Science.gov (United States)

    Gierach, Gretchen L.; Patel, Deesha A.; Pfeiffer, Ruth M.; Figueroa, Jonine D.; Linville, Laura; Papathomas, Daphne; Johnson, Jason M.; Chicoine, Rachael E.; Herschorn, Sally D.; Shepherd, John A.; Wang, Jeff; Malkov, Serghei; Vacek, Pamela M.; Weaver, Donald L.; Fan, Bo; Mahmoudzadeh, Amir Pasha; Palakal, Maya; Xiang, Jackie; Oh, Hannah; Horne, Hisani N.; Sprague, Brian L.; Hewitt, Stephen M.; Brinton, Louise A.; Sherman, Mark E.

    2016-01-01

    Elevated mammographic density (MD) is an established breast cancer risk factor. Reduced involution of terminal duct lobular units (TDLUs), the histologic source of most breast cancers, has been associated with higher MD and breast cancer risk. We investigated relationships of TDLU involution with area and volumetric MD, measured throughout the breast and surrounding biopsy targets (peri-lesional). Three measures inversely related to TDLU involution (TDLU count/mm2, median TDLU span, median acini count/TDLU) assessed in benign diagnostic biopsies from 348 women, ages 40–65, were related to MD area (quantified with thresholding software) and volume (assessed with a density phantom) by analysis of covariance, stratified by menopausal status and adjusted for confounders. Among premenopausal women, TDLU count was directly associated with percent peri-lesional MD (P-trend=0.03), but not with absolute dense area/volume. Greater TDLU span was associated with elevated percent dense area/volume (P-trendbreast cancer risk suggest that associations of MD with breast cancer may partly reflect amounts of at-risk epithelium. If confirmed, these results could suggest a prevention paradigm based on enhancing TDLU involution and monitoring efficacy by assessing MD reduction. PMID:26645278

  8. Dislocation-density based description of the deformation of a composite material

    Science.gov (United States)

    Schulz, K.; Sudmanns, M.; Gumbsch, P.

    2017-09-01

    Composite materials consisting of hard particles in a ductile metallic matrix are of major interest since their strength and deformability can be dramatically changed by varying volume fraction, size and shape of the particles. Understanding dislocation motion in composite materials as the cause of plastic deformation therefore is an important task. Recently, advanced dislocation-based continuum theories of plasticity have been developed for performing meaningful averages over systems of straight and curved dislocation lines in a continuum approach. In this paper, we focus on a single slip heterogeneous microstructure and investigate how the dislocation interactions can be represented in an averaged dislocation density based continuum description. The representation of strong dislocation density gradients is discussed in the context of a formulation, which aims at a coarse-grained resolution. We introduce a set of dislocation density evolution equations which account for the formation and dissolution of dislocation dipoles. By applying the model to a composite structure, we demonstrate that the dislocation density based description can well describe the physical processes in the microstructure and a comparison to discrete dislocation dynamics simulations shows good agreement for the relaxation behavior of the considered composites.

  9. Graphene, a material for high temperature devices; intrinsic carrier density, carrier drift velocity, and lattice energy

    CERN Document Server

    Yin, Yan; Wang, Li; Jin, Kuijuan; Wang, Wenzhong

    2016-01-01

    Heat has always been a killing matter for traditional semiconductor machines. The underlining physical reason is that the intrinsic carrier density of a device made from a traditional semiconductor material increases very fast with a rising temperature. Once reaching a temperature, the density surpasses the chemical doping or gating effect, any p-n junction or transistor made from the semiconductor will fail to function. Here, we measure the intrinsic Fermi level (|E_F|=2.93k_B*T) or intrinsic carrier density (n_in=3.87*10^6 cm^-2 K^-2*T^2), carrier drift velocity, and G mode phonon energy of graphene devices and their temperature dependencies up to 2400 K. Our results show intrinsic carrier density of graphene is an order of magnitude less sensitive to temperature than those of Si or Ge, and reveal the great potentials of graphene as a material for high temperature devices. We also observe a linear decline of saturation drift velocity with increasing temperature, and identify the temperature coefficients of ...

  10. Energetic multifunctionalized nitraminopyrazoles and their ionic derivatives: ternary hydrogen-bond induced high energy density materials.

    Science.gov (United States)

    Yin, Ping; Parrish, Damon A; Shreeve, Jean'ne M

    2015-04-15

    Diverse functionalization was introduced into the pyrazole framework giving rise to a new family of ternary hydrogen-bond induced high energy density materials. By incorporating extended cationic interactions, nitramine-based ionic derivatives exhibit good energetic performance and enhanced molecular stability. Performance parameters including heats of formation and detonation properties were calculated by using Gaussian 03 and EXPLO5 v6.01 programs, respectively. It is noteworthy to find that 5-nitramino-3,4-dinitropyrazole, 4, has a remarkable measured density of 1.97 g cm(-3) at 298 K, which is consistent with its crystal density (2.032 g cm(-3), 150 K), and ranks highest among azole-based CHNO compounds. Energetic evaluation indicates that, in addition to the molecular compound 4, some ionic derivatives, 9, 11, 12, 17, 19, and 22, also have high densities (1.83-1.97 g cm(-3)), excellent detonation pressures and velocities (P, 35.6-41.6 GPa; vD, 8880-9430 m s(-1)), as well as acceptable impact and friction sensitivities (IS, 4-30 J; FS, 40-240 N). These attractive features highlight the application potential of nitramino hydrogen-bonded interactions in the design of advanced energetic materials.

  11. The contact density to characterize the mechanics of cohesive granular materials: application to snow microstructure modeling.

    Science.gov (United States)

    Gaume, Johan; Löwe, Henning

    2016-04-01

    Microstructural properties are essential to characterize the mechanics of loose and cohesive granular materials such as snow. In particular, mechanical properties and physical processes of porous media are often related to the volume fraction ν. Low-density microstructures typically allow for considerable structural diversity at a given volume fraction, leading to uncertainties in modeling approaches using ν-based parametrizations only. We have conducted discrete element simulations of cohesive granular materials with initial configurations which are drawn from Baxter's sticky hard sphere (SHS) model. This method allows to control independently the initial volume fraction ν and the average coordination number Z. We show that variations in elasticity and strength of the samples can be fully explained by the initial contact density C = νZ over a wide range of volume fractions and coordination numbers. Hence, accounting for the contact density C allows to resolve the discrepancies in particle based modeling between samples with similar volume fractions but different microstructures. As an application, we applied our method to the microstructure of real snow samples which have been imaged by micro-computed tomography and reconstructed using the SHS model. Our new approach opens a promising route to evaluate snow physical and mechanical properties from field measurements, for instance using the Snow Micro Penetrometer (SMP), by linking the penetration resistance to the contact density.

  12. Advanced High Energy Density Secondary Batteries with Multi-Electron Reaction Materials.

    Science.gov (United States)

    Chen, Renjie; Luo, Rui; Huang, Yongxin; Wu, Feng; Li, Li

    2016-10-01

    Secondary batteries have become important for smart grid and electric vehicle applications, and massive effort has been dedicated to optimizing the current generation and improving their energy density. Multi-electron chemistry has paved a new path for the breaking of the barriers that exist in traditional battery research and applications, and provided new ideas for developing new battery systems that meet energy density requirements. An in-depth understanding of multi-electron chemistries in terms of the charge transfer mechanisms occuring during their electrochemical processes is necessary and urgent for the modification of secondary battery materials and development of secondary battery systems. In this Review, multi-electron chemistry for high energy density electrode materials and the corresponding secondary battery systems are discussed. Specifically, four battery systems based on multi-electron reactions are classified in this review: lithium- and sodium-ion batteries based on monovalent cations; rechargeable batteries based on the insertion of polyvalent cations beyond those of alkali metals; metal-air batteries, and Li-S batteries. It is noted that challenges still exist in the development of multi-electron chemistries that must be overcome to meet the energy density requirements of different battery systems, and much effort has more effort to be devoted to this.

  13. High density porous polyethylene material (Medpor) as an unwrapped orbital implant

    Institute of Scientific and Technical Information of China (English)

    CHEN Yan-hong; CUI Hong-guang

    2006-01-01

    Objective: To introduce the clinical effect among patients who received an unwrapped orbital implant with high density porous polyethylene material (Medpor) after enucleation or evisceration. Methods: Retrospective analysis of a series of 302 patients with anophthalmia who underwent placement of an unwrapped high density porous polyethylene orbital implant. We compared the patients (n=180) who accepted primary implant placement with those (n=122) who accepted secondary implant placement. Parameters evaluated included: age at time of surgery, date of surgery, sex, implant type and size, surgery type, the surgical procedure and technique performed, and complications. Results: The time of follow-up ranged from 2.0 to 58.0 months (mean 32.5 months). A total of 5 of 302 (1.66%) cases had documented postoperative complications. The following problems were noted after surgery: implant exposure, 3 patients (0.99%); implant removed due to orbital infection, 1 patient (0.34%); ptosis, 1 patient (0.34%). There were no significant complications observed in other 297 cases and all implants showed good orbital motility. The clinical effect of primary implant placement is better than that of secondary placement. Conclusion: High density porous polyethylene material can be used successfully as an unwrapped orbital implant in anopthalmic socket surgery with minimal complications. The material is well tolerated, nonantigenic and has low rate of infection and migration.

  14. Novel LLM series high density energy materials: Synthesis, characterization, and thermal stability

    Science.gov (United States)

    Pagoria, Philip; Zhang, Maoxi; Tsyshevskiy, Roman; Kuklja, Maija

    Novel high density energy materials must satisfy specific requirements, such as an increased performance, reliably high stability to external stimuli, cost-efficiency and ease of synthesis, be environmentally benign, and be safe for handling and transportation. During the last decade, the attention of researchers has drifted from widely used nitroester-, nitramine-, and nitroaromatic-based explosives to nitrogen-rich heterocyclic compounds. Good thermal stability, the low melting point, high density, and moderate sensitivity make heterocycle materials attractive candidates for use as oxidizers in rocket propellants and fuels, secondary explosives, and possibly as melt-castable ingredients of high explosive formulations. In this report, the synthesis, characterization, and results of quantum-chemical DFT study of thermal stability of LLM-191, LLM-192 and LLM-200 high density energy materials are presented. Work performed under the auspices of the DOE by the LLNL (Contract DE-AC52-07NA27344). This research is supported in part by ONR (Grant N00014-12-1-0529) and NSF. We used NSF XSEDE (Grant DMR-130077) and DOE NERSC (Contract DE-AC02-05CH11231) resources.

  15. 40 CFR 63.7886 - What are the general standards I must meet for my affected remediation material management units?

    Science.gov (United States)

    2010-07-01

    ... meet for my affected remediation material management units? 63.7886 Section 63.7886 Protection of... meet for my affected remediation material management units? (a) For each remediation material... material management units exempted under paragraph (c) or (d) of this section. (b) For each affected...

  16. Tailoring correlations of the local density of states in disordered photonic materials

    CERN Document Server

    Riboli, F; Monaco, G; Caselli, N; Intonti, F; Gurioli, M; Skipetrov, S E

    2016-01-01

    We present experimental evidence for the different mechanisms driving the fluctuations of the local density of states (LDOS) in disordered photonic systems. We establish a clear link between the microscopic structure of the material and the frequency correlation function of LDOS accessed by a near-field hyperspectral imaging technique. We show, in particular, that short- and long-range frequency correlations of LDOS are controlled by different physical processes (multiple or single scattering processes, respectively) that can be---to some extent---manipulated independently. We also demonstrate that the single scattering contribution to the LDOS fluctuations is sensitive to subwavelength features of the material and, in particular, to the correlation length of its dielectric function. Our work paves the way towards a complete control of statistical properties of disordered photonic systems, allowing for designing materials with predefined LDOS correlations.

  17. Critical parameters governing energy density of Li-storage cathode materials unraveled by confirmatory factor analysis

    Science.gov (United States)

    Sohn, Kee-Sun; Han, Su Cheol; Park, Woon Bae; Pyo, Myoungho

    2016-03-01

    Despite extensive effort during the past few decades, a comprehensive understanding of the key variables governing the electrochemical properties of cathode materials in Li-ion batteries is still far from complete. To elucidate the critical parameters affecting energy density (ED) and capacity (Q) retention in layer and spinel cathodes, we data-mine the existing experimental data via confirmatory factor analysis (CFA) based on a structural equation model (SEM), which is a proven, versatile tool in understanding complex problems in the social science. The data sets are composed of 18 and 15 parameters extracted from 38 layer and 33 spinel compounds, respectively. CFA reveals the irrelevance of Q retention to all the parameters we adopt, but it also reveals the sensitive variations of ED with specific parameters. We validate the usefulness of CFA in material science and pinpointed critical parameters for high-ED cathodes, hoping to suggest a new insight in materials design.

  18. Scalable Sub-micron Patterning of Organic Materials Toward High Density Soft Electronics.

    Science.gov (United States)

    Kim, Jaekyun; Kim, Myung-Gil; Kim, Jaehyun; Jo, Sangho; Kang, Jingu; Jo, Jeong-Wan; Lee, Woobin; Hwang, Chahwan; Moon, Juhyuk; Yang, Lin; Kim, Yun-Hi; Noh, Yong-Young; Jaung, Jae Yun; Kim, Yong-Hoon; Park, Sung Kyu

    2015-09-28

    The success of silicon based high density integrated circuits ignited explosive expansion of microelectronics. Although the inorganic semiconductors have shown superior carrier mobilities for conventional high speed switching devices, the emergence of unconventional applications, such as flexible electronics, highly sensitive photosensors, large area sensor array, and tailored optoelectronics, brought intensive research on next generation electronic materials. The rationally designed multifunctional soft electronic materials, organic and carbon-based semiconductors, are demonstrated with low-cost solution process, exceptional mechanical stability, and on-demand optoelectronic properties. Unfortunately, the industrial implementation of the soft electronic materials has been hindered due to lack of scalable fine-patterning methods. In this report, we demonstrated facile general route for high throughput sub-micron patterning of soft materials, using spatially selective deep-ultraviolet irradiation. For organic and carbon-based materials, the highly energetic photons (e.g. deep-ultraviolet rays) enable direct photo-conversion from conducting/semiconducting to insulating state through molecular dissociation and disordering with spatial resolution down to a sub-μm-scale. The successful demonstration of organic semiconductor circuitry promise our result proliferate industrial adoption of soft materials for next generation electronics.

  19. Ab initio density-functional calculations in materials science: from quasicrystals over microporous catalysts to spintronics.

    Science.gov (United States)

    Hafner, Jürgen

    2010-09-29

    During the last 20 years computer simulations based on a quantum-mechanical description of the interactions between electrons and atomic nuclei have developed an increasingly important impact on materials science, not only in promoting a deeper understanding of the fundamental physical phenomena, but also enabling the computer-assisted design of materials for future technologies. The backbone of atomic-scale computational materials science is density-functional theory (DFT) which allows us to cast the intractable complexity of electron-electron interactions into the form of an effective single-particle equation determined by the exchange-correlation functional. Progress in DFT-based calculations of the properties of materials and of simulations of processes in materials depends on: (1) the development of improved exchange-correlation functionals and advanced post-DFT methods and their implementation in highly efficient computer codes, (2) the development of methods allowing us to bridge the gaps in the temperature, pressure, time and length scales between the ab initio calculations and real-world experiments and (3) the extension of the functionality of these codes, permitting us to treat additional properties and new processes. In this paper we discuss the current status of techniques for performing quantum-based simulations on materials and present some illustrative examples of applications to complex quasiperiodic alloys, cluster-support interactions in microporous acid catalysts and magnetic nanostructures.

  20. Segregation of Granular Material in Two and Three-Dimensional Units

    Indian Academy of Sciences (India)

    Sandhya Mishra; Ankit Namdev; Munindra Bisen; Jeeshan Ahmad; Vishal Mishra

    2016-10-01

    Segregation of particulate materials in mixtures is controlledby differences in density, shape, and size. Experiments on segregationwere performed in two and three-dimensional demonstrationunits. The results conclusively indicated that the segregationof solids is affected by the shape, size and density ofgranular particles.

  1. Survey of radioactive material shipments in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, J.L.; Cloninger, M.O.; Cole, B.M.; Medford, A.E.

    1976-04-01

    The survey period was from March 1, 1974, through February 28, 1975. Of over 15,000 NRC and Agreement States licensees, and ERDA prime contractors, 2275 received questionnaire packets. Approximately 59 percent of those recipients responded to the survey; of these respondents, 35 percent reported shipping activities. Based on the number of packages shipped annually, the major nuclides were /sup 131/I, /sup 125/I, /sup 99m/Tc, /sup 99/Mo, and /sup 238/U, while those shipped in the greatest amounts (grams or curies) were /sup 60/Co, /sup 192/Ir, and /sup 238/U. The majority of package types shipped were Types A and LS (low specific activity), while the most common modes of transport were rail and truck. The shipping activities of approximately 14,600 minor shippers were estimated to be on the order of 200,000 radioactive packages/year. The combined annual shipping activities of 761 major shippers, SNM licensees, and ERDA contractors who responded were estimated to be approximately 300,000 packages of SNM and Source Material plus 800,000 packages containing nuclides other than SNM or Source Material. There were also about 800,000 packages (mostly exempt) shipped by 21 apparent major shippers who responded to a part of the survey intended for minor shippers. Also, classified data containing information regarding nonweapons shipments indicated 850 packages. The possibility of using the survey data for projection use was briefly investigated.

  2. The effect of light curing units, curing time, and veneering materials on resin cement microhardness

    Directory of Open Access Journals (Sweden)

    Nurcan Ozakar Ilday

    2013-06-01

    Conclusion: Light-curing units, curing time, and veneering materials are important factors for achieving adequate dual cure resin composite microhardness. High-intensity light and longer curing times resulted in the highest microhardness values.

  3. Anomalous Lithium Adsorption Propensity of Monolayer Carbonaceous Materials: A Density Functional Study

    Indian Academy of Sciences (India)

    SWATI PANIGRAHI; DEIVASIGAMANI UMADEVI; G NARAHARI SASTRY

    2016-10-01

    Interaction between lithium and carbonaceous materials has gained a lot of importance in lithium battery industry as an important source of energy and storage. The size, dimension, curvature and chirality of the carbonaceous materials are found to be very important factors in controlling the sequential binding oflithium. The propensity of lithium binding to the monolayer carbonaceous materials has been studied using Density functional theory (DFT). Structural and energetical parameters of the complexes have been analyzed through interaction energy, sequential energy, Mulliken population analysis and spin density distribution. Spindensity of odd Li doped systems reveals the preferences for addition of further lithium atoms on the surface. Upon analyzing the interaction energy in armchair carbon nanotubes (A-CNTs) and zigzag carbon nanotubes (Z-CNTs), it has been observed that external and internal surfaces of CNTs have contrasting binding preferences for sequential addition of Li atoms. Internal surface is found to be more feasible site for lithium adsorption than the external surface. This current study provides fundamental understanding of the mechanism of lithium adsorption in lithium battery.

  4. Nanoscale Tunable Strong Carrier Density Modulation of 2D Materials for Metamaterials and Other Tunable Optoelectronics

    Science.gov (United States)

    Peng, Cheng; Efetov, Dmitri; Shiue, Ren-Jye; Nanot, Sebastien; Hempel, Marek; Kong, Jing; Koppens, Frank; Englund, Dirk

    Strong spatial tunability of the charge carrier density at nanoscale is essential to many 2D-material-based electronic and optoelectronic applications. As an example, plasmonic metamaterials with nanoscale dimensions would make graphene plasmonics at visible and near-infrared wavelengths possible. However, existing gating techniques based on conventional dielectric gating geometries limit the spatial resolution and achievable carrier concentration, strongly restricting the available wavelength, geometry, and quality of the devices. Here, we present a novel spatially selective electrolyte gating approach that allows for in-plane spatial Fermi energy modulation of 2D materials of more than 1 eV (carrier density of n = 1014 cm-2) across a length of 2 nm. We present electrostatic simulations as well as electronic transport, photocurrent, cyclic voltammetry and optical spectroscopy measurements to characterize the performance of the gating technique applied to graphene devices. The high spatial resolution, high doping capacity, full tunability and self-aligned device geometry of the presented technique opens a new venue for nanoscale metamaterial engineering of 2D materials for complete optical absorption, nonlinear optics and sensing, among other applications.

  5. Characterization of Thin Film Materials using SCAN meta-GGA, an Accurate Nonempirical Density Functional

    Science.gov (United States)

    Buda, I. G.; Lane, C.; Barbiellini, B.; Ruzsinszky, A.; Sun, J.; Bansil, A.

    2017-03-01

    We discuss self-consistently obtained ground-state electronic properties of monolayers of graphene and a number of ’beyond graphene’ compounds, including films of transition-metal dichalcogenides (TMDs), using the recently proposed strongly constrained and appropriately normed (SCAN) meta-generalized gradient approximation (meta-GGA) to the density functional theory. The SCAN meta-GGA results are compared with those based on the local density approximation (LDA) as well as the generalized gradient approximation (GGA). As expected, the GGA yields expanded lattices and softened bonds in relation to the LDA, but the SCAN meta-GGA systematically improves the agreement with experiment. Our study suggests the efficacy of the SCAN functional for accurate modeling of electronic structures of layered materials in high-throughput calculations more generally.

  6. High-Tc superconductor/linear low density polyethylene (LLDPE) composite materials for diamagnetic applications

    Science.gov (United States)

    Bhadrakumari, S.; Predeep, P.

    2006-08-01

    A series of composite samples of YBa2Cu3O7-x and linear low density polyethylene (Y-123/LLDPE) with volume percentage ranging from 0 to 75% was prepared. The crystallinity of the composites was studied using x-ray diffraction (XRD) patterns. It is found that the percentage of crystallinity in the composite samples increases with increasing volume of the LLDPE. A four-phase system for the composite materials may be inferred from a combination of XRD and density data. Repulsive force measurements showed that the diamagnetic properties were preserved in the composites and the samples exhibited appreciable magnetic levitation forces and this force increases with increasing volume fraction of the superconductor filler.

  7. Continuous Learning Graphical Knowledge Unit for Cluster Identification in High Density Data Sets

    Directory of Open Access Journals (Sweden)

    K.K.L.B. Adikaram

    2016-12-01

    Full Text Available Big data are visually cluttered by overlapping data points. Rather than removing, reducing or reformulating overlap, we propose a simple, effective and powerful technique for density cluster generation and visualization, where point marker (graphical symbol of a data point overlap is exploited in an additive fashion in order to obtain bitmap data summaries in which clusters can be identified visually, aided by automatically generated contour lines. In the proposed method, the plotting area is a bitmap and the marker is a shape of more than one pixel. As the markers overlap, the red, green and blue (RGB colour values of pixels in the shared region are added. Thus, a pixel of a 24-bit RGB bitmap can code up to 224 (over 1.6 million overlaps. A higher number of overlaps at the same location makes the colour of this area identical, which can be identified by the naked eye. A bitmap is a matrix of colour values that can be represented as integers. The proposed method updates this matrix while adding new points. Thus, this matrix can be considered as an up-to-time knowledge unit of processed data. Results show cluster generation, cluster identification, missing and out-of-range data visualization, and outlier detection capability of the newly proposed method.

  8. Preliminary Material Properties Handbook. Volume 1: English Units

    Science.gov (United States)

    2000-07-01

    4.2 Aluminium 4.8 5.3 Titanium 1.6 2.0 Tungsten 5.2 5.9 Niobium 2.4 2.8 Hafnium 0.1 0.4 Zirconium — 0.015 Magnesium — 0.02 Boron — 0.015 Cerium — 0.01...HAYNES® HR-120® alloy Inconel alloy MA754 EP741NP (Russian Powder Material) Cobalt-Base Alloys Other Alloys C-103 (Niobium- Hafnium -Titanium) HEAT...thermal expansion for EP741NP superalloy. 6-37 6.4 COBALT-BASE ALLOYS No alloys included at this time. 6.5 OTHER ALLOYS 6.5.1 C-103 (NIOBIUM- HAFNIUM

  9. Preliminary Material Properties Handbook. Volume 2: SI Units

    Science.gov (United States)

    2000-07-01

    Aluminium 4.8 5.3 Titanium 1.6 2.0 Tungsten 5.2 5.9 Niobium 2.4 2.8 Hafnium 0.1 0.4 Zirconium — 0.015 Magnesium — 0.02 Boron — 0.015 Cerium — 0.01...alloy MA754 EP741NP (Russian Powder Material) Cobalt-Base Alloys Other Alloys C-103 (Niobium- Hafnium -Titanium) HEAT-RESISTANT ALLOYS Heat-resistant... HAFNIUM -TITANIUM) 6.5.1.0 Comments and Properties — C-103 is a Niobium-based alloy (Nb-10Hf-0.7 to1.3Ti) used for elevated temperature applications with

  10. ELT Materials Design of a Speaking Unit based on Needs Analysis

    Institute of Scientific and Technical Information of China (English)

    LIU Ai-juan; TONG Xing-hong; DU Wen-jing

    2016-01-01

    In this article, the authors design a speaking unit based on needs analysis following Hutchinson and Waters’(1987) model. First, the rationale in designing this unit is introduced, which involves the teaching approach adopted and relevant theo-ries in organizing the materials. Then, the teaching plan of this speaking unit is provided and some activities are designed to cre-ate an authentic and optimal situation for students to practice their speaking skill.

  11. Distributed material density and anisotropy for optimized eigenfrequency of 2D continua

    DEFF Research Database (Denmark)

    Pedersen, Pauli; Pedersen, Niels Leergaard

    2015-01-01

    with respect to material density and from this values of the element OC. Each factor of this expression has a physical interpretation. Stated alternatively, the optimization problem of material distribution is converted into a problem of determining a design of uniform OC values. The constitutive matrices...... are described by non-dimensional matrices with unity norms of trace and Frobenius, and thus this part of the optimized design has no influence on the mass distribution. Gradients of eigenfrequency with respect to the components of these non-dimensional constitutive matrices are therefore simplified......, and an additional optimization criterion shows that the optimized redesign of anisotropy are described directly by the element strains. The fact that all components of an optimal constitutive matrix are expressed by the components of a strain state, imply a reduced number of independent components of an optimal...

  12. Development of high power density cathode materials for Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Ketterer, B.; Vasilchina, H.; Seemann, K.; Ulrich, S.; Besser, H.; Pfleging, W.; Kaiser, T.; Adelhelm, C. [Forschungszentrum Karlsruhe (Germany). IMF I

    2008-10-15

    Cathode material for Li-ion batteries can be synthesised by r.f. magnetron sputtering of LiCoO{sub 2} targets in a pure Ar plasma. This technique is suitable for large-scale implementation in foil coating set-ups. By choosing the process parameters and by employing post heat treatment nanocrystalline, stoichiometrical LiCoO{sub 2} films can be fabricated which exhibit the desired high temperature phase. The determination of the elementary composition is possible by optical emission spectroscopy including plasma stimulation and carrier gas temperature extraction. The proof of crystal structure is carried out by X-ray diffraction and Raman spectroscopy. Heat treatment can be conventionally realised in a furnace or by laser impact. With regard to increasing the power density, the surface of the cathode material can be enhanced six-fold by laser-assisted surface patterning. (orig.)

  13. Isoreticular expansion of metal-organic frameworks with triangular and square building units and the lowest calculated density for porous crystals.

    Science.gov (United States)

    Furukawa, Hiroyasu; Go, Yong Bok; Ko, Nakeun; Park, Young Kwan; Uribe-Romo, Fernando J; Kim, Jaheon; O'Keeffe, Michael; Yaghi, Omar M

    2011-09-19

    The concept and occurrence of isoreticular (same topology) series of metal-organic frameworks (MOFs) is reviewed. We describe the preparation, characterization, and crystal structures of three new MOFs that are isoreticular expansions of known materials with the tbo (Cu(3)(4,4',4''-(benzene-1,3,5-triyl-tris(benzene-4,1-diyl))tribenzoate)(2), MOF-399) and pto topologies (Cu(3)(4,4',4''-(benzene-1,3,5-triyl-tribenzoate)(2), MOF-143; Cu(3)(4,4',4''-(triazine-2,4,6-triyl-tris(benzene-4,1-diyl))tribenzoate)(2), MOF-388). One of these materials (MOF-399) has a unit cell volume 17 times larger than that of the first reported material isoreticular to it, and has the highest porosity (94%) and lowest density (0.126 g cm(-3)) of any MOFs reported to date.

  14. Quasi-1D van der Waals materials as high current-density local interconnects (Conference Presentation)

    Science.gov (United States)

    Stolyarov, Maxim; Aytan, Ece; Bloodgood, Matthew; Salguero, Tina T.; Balandin, Alexander A.

    2016-09-01

    The continuous downscaling of interconnect dimensions in combination with the introduction of low-k dielectrics has increased the number of heat dissipation, integration and reliability challenges in modern electronics. As a result, there is a strong need for new materials that have high current-carrying capacity for applications as nanoscale interconnects. In this presentation, we show that quasi-one-dimensional (1D) van der Waals metals such as TaSe3 have excellent breakdown current density exceeding that of 5 MA/cm2. This value is above that currently achievable in conventional copper or aluminum wires. The quasi-1D van der Waals materials are characterized by strong bonds along one dimension and weak van der Waals bonds along two other dimensions. The material for this study was grown by the chemical vapor transport (CVT) method. Both mechanical and chemical exfoliation methods were used to fabricate nanowires with lateral dimensions below 100 nm. The dimensions of the quasi-1D nanowires were verified with scanning electron microscopy (SEM) and atomic force microscopy (AFM). The metal (Ti/Au) contacts for the electrical characterization were deposited using electron beam evaporation (EBE). The measurements were conducted on a number of prototype interconnects with multiple electric contacts to ensure reproducibility. The obtained results suggest that quasi-1D van der Waals metals present a feasible alternative to conventional copper interconnects in terms of the current-carrying capacity and the breakdown current-density. This work was supported, in part, by the SRC and DARPA through STARnet Center for Function Accelerated nanoMaterial Engineering (FAME).

  15. Breeding Livestock. A Unit for Teachers of Vocational Agriculture. Production Agriculture Curriculum Materials Project.

    Science.gov (United States)

    O'Bryan, Robert C.

    Designed to provide instructional materials for use by vocational agriculture teachers, this unit on breeding livestock contains materials for use in teaching the importance of breeding, the physiology of livestock breeding, reproductive processes, sire selection, and breeding systems. Lessons on each of these competencies contain the following:…

  16. "Their Little Wooden Bricks": A History of the Material Culture of Kindergarten in the United States

    Science.gov (United States)

    Prochner, Larry

    2011-01-01

    This article explores the material culture of kindergarten in the United States in relation to the production and consumption of materials and kindergarten theory and pedagogy. The focus is on Friedrich Froebel's building gifts as they were manufactured and sold by the Milton Bradley Company from 1869 to 1939. A review of trade catalogues over the…

  17. Detonation shock dynamics calibration for pBX 9502 with temperature, density, and material lot variations

    Energy Technology Data Exchange (ETDEWEB)

    Hill, Larry G [Los Alamos National Laboratory; Aslam, Tariq D [Los Alamos National Laboratory

    2010-01-01

    We present a methodology for scaling the detonation shock dynamics D{sub n}[{kappa}] calibration function to accommodate variations in the HE starting material. We apply our model to the insensitive TATB-based explosive PBX 9502, for which we have enough front curvature rate stick data to characterize three material attributes: initial temperature T{sub 0}, nominal density {rho}{sub 0}, and manufacturing lot (representing different microstructures). A useful feature of the model is that it returns an absolute estimate for the reaction zone thickness, {delta}. Lacking demonstrated material metrics(s), we express microstructural variation indirectly, in terms of its effect on {delta}. This results in a D{sub n}[{kappa}] function that depends on T{sub 0}, {rho}{sub 0}, and {delta}. After examining the separate effects of each parameter on D{sub n}[{kappa}], we compute an arc geometry as a validation problem. We compare the calculation to a PBX 9502 arc experiment that was pressed from one of the calibrated HE lots. The agreement between the model and experiment is excellent. We compute worst, nominal, and best-performing material parameter combinations to show how much difference accrues throughout the arc.

  18. Relationships among Alcohol Outlet Density, Alcohol Use, and Intimate Partner Violence Victimization among Young Women in the United States

    Science.gov (United States)

    Waller, Martha W.; Iritani, Bonita J.; Christ, Sharon L.; Clark, Heddy Kovach; Moracco, Kathryn E.; Halpern, Carolyn Tucker; Flewelling, Robert L.

    2012-01-01

    Greater access to alcohol has been widely found to be associated with many negative outcomes including violence perpetration. This study examines the relationship between alcohol outlet density, alcohol use, and intimate partner violence (IPV) victimization among young women in the United States. A direct association between alcohol outlet density…

  19. Motor unit properties of biceps brachii in chronic stroke patients assessed with high-density surface EMG

    NARCIS (Netherlands)

    Kallenberg, L.A.C.; Hermens, Hermanus J.

    2009-01-01

    The aim of this study was to investigate motor unit (MU) characteristics of the biceps brachii in post-stroke patients, using high-density surface electromyography (sEMG). Eighteen chronic hemiparetic stroke patients took part. The Fugl-Meyer score for the upper extremity was assessed. Subjects

  20. Effective density of Aquadag and fullerene soot black carbon reference materials used for SP2 calibration

    Directory of Open Access Journals (Sweden)

    M. Gysel

    2011-08-01

    Full Text Available The mass and effective density of black carbon (BC particles generated from aqueous suspensions of Aquadag and fullerene soot was measured and parametrized as a function of their mobility diameter. The measurements were made by two independent research groups by operating a differential mobility analyser (DMA in series with an aerosol particle mass analyser (APM or a Couette centrifugal particle mass analyser (CPMA. Consistent and reproducible results were found in this study for different production lots of Aquadag, indicating that the effective density of these particles is a stable quantity and largely unaffected by differences in aerosol generation procedures and suspension treatments. The effective density of fullerene soot particles from one production lot was also found to be stable and independent of suspension treatments. Some difference to previous literature data was observed for both Aquadag and fullerene soot at larger particle diameters. Knowledge of the exact relationship between mobility diameter and particle mass is of great importance, as DMAs are commonly used to size-select particles from BC reference materials for calibration of single particle soot photometers (SP2, which quantitatively detect the BC mass in single particles.

  1. Effective density of Aquadag and fullerene soot black carbon reference materials used for SP2 calibration

    Directory of Open Access Journals (Sweden)

    M. Gysel

    2011-12-01

    Full Text Available The mass and effective density of black carbon (BC particles generated from aqueous suspensions of Aquadag and fullerene soot was measured and parametrized as a function of their mobility diameter. The measurements were made by two independent research groups by operating a differential mobility analyser (DMA in series with an aerosol particle mass analyser (APM or a Couette centrifugal particle mass analyser (CPMA. Consistent and reproducible results were found in this study for different production lots of Aquadag, indicating that the effective density of these particles is a stable quantity and largely unaffected by differences in aerosol generation procedures and suspension treatments. The effective density of fullerene soot particles from one production lot was also found to be stable and independent of suspension treatments. Some differences to previous literature data were observed for both Aquadag and fullerene soot at larger particle diameters. Knowledge of the exact relationship between mobility diameter and particle mass is of great importance, as DMAs are commonly used to size-select particles from BC reference materials for calibration of single particle soot photometers (SP2, which quantitatively detect the BC mass in single particles.

  2. A Noncontact Measurement Technique for the Density and Thermal Expansion Coefficient of Solid and Liquid Materials

    Science.gov (United States)

    Chung, Sang K.; Thiessen, David B.; Rhim, Won-Kyu

    1996-01-01

    A noncontact measurement technique for the density and the thermal expansion refractory materials in their molten as well as solid phases is presented. This technique is based on the video image processing of a levitated sample. Experiments were performed using the high-temperature electrostatic levitator (HTESL) at the Jet Propulsion Laboratory in which 2-3 mm diameter samples can be levitated, melted, and radiatively cooled in a vacuum. Due to the axisymmetric nature of the molten samples when levitated in the HTESL, a rather simple digital image analysis can be employed to accurately measure the volumetric change as a function of temperature. Density and the thermal expansion coefficient measurements were made on a pure nickel sample to test the accuracy of the technique in the temperature range of 1045-1565 C. The result for the liquid phase density can be expressed by p = 8.848 + (6.730 x 10(exp -4)) x T (degC) g/cu cm within 0.8% accuracy, and the corresponding thermal expansion coefficient can be expressed by Beta=(9.419 x 10(exp -5)) - (7.165 x 10(exp -9) x T (degC)/K within 0.2% accuracy.

  3. AFM-porosimetry: density and pore volume measurements of particulate materials.

    Science.gov (United States)

    Sörensen, Malin H; Valle-Delgado, Juan J; Corkery, Robert W; Rutland, Mark W; Alberius, Peter C

    2008-06-01

    We introduced the novel technique of AFM-porosimetry and applied it to measure the total pore volume of porous particles with a spherical geometry. The methodology is based on using an atomic force microscope as a balance to measure masses of individual particles. Several particles within the same batch were measured, and by plotting particle mass versus particle volume, the bulk density of the sample can be extracted from the slope of the linear fit. The pore volume is then calculated from the densities of the bulk and matrix materials, respectively. In contrast to nitrogen sorption and mercury porosimetry, this method is capable of measuring the total pore volume regardless of pore size distribution and pore connectivity. In this study, three porous samples were investigated by AFM-porosimetry: one ordered mesoporous sample and two disordered foam structures. All samples were based on a matrix of amorphous silica templated by a block copolymer, Pluronic F127, swollen to various degrees with poly(propylene glycol). In addition, the density of silica spheres without a template was measured by two independent techniques: AFM and the Archimedes principle.

  4. Strength and Density of Geopolymer Mortar Cured at Ambient Temperature for Use as Repair Material

    Science.gov (United States)

    Warid Wazien, A. Z.; Bakri Abdullah, Mohd Mustafa Al; Abd. Razak, Rafiza; Mohd Remy Rozainy, M. A. Z.; Faheem Mohd Tahir, Muhammad

    2016-06-01

    Geopolymers produced by synthesizing aluminosilicate source materials with an alkaline activator solution promised an excellent properties akin to the existing construction material. This study focused on the effect of various binder to sand ratio on geopolymer mortar properties. Mix design of geopolymer mortar was produced using NaOH concentration of 12 molars, ratio of fly ash/alkaline activator and ratio Na2SiO3/NaOH of 2.0 and 2.5 respectively. Samples subsequently ware cured at ambient temperature. The properties of geopolymer mortar were analysed in term of compressive strength and density at different period which are on the 3rd and 7th day of curing. Experimental results revealed that the addition of sand slightly increase the compressive strength of geopolymer. The optimum compressive strength obtained was up to 31.39 MPa on the 7th day. The density of geopolymer mortar was in the range between 2.0 g/cm3 to 2.23 g/cm3. Based on this findings, the special properties promoted by geopolymer mortar display high potential to be implemented in the field of concrete patch repair.

  5. NUMATH: a nuclear-material-holdup estimator for unit operations and chemical processes

    Energy Technology Data Exchange (ETDEWEB)

    Krichinsky, A.M.

    1983-02-01

    A computer program, NUMATH (Nuclear Material Holdup Estimator), has been developed to estimate compositions of materials in vessels involved in unit operations and chemical processes. This program has been implemented in a remotely operated nuclear fuel processing plant. NUMATH provides estimates of the steady-state composition of materials residing in process vessels until representative samples can be obtained and chemical analyses can be performed. Since these compositions are used for inventory estimations, the results are determined for the cataloged in container-oriented files. The estimated compositions represent materials collected in applicable vessels - including consideration for materials previously acknowledged in these vessels. The program utilizes process measurements and simple performance models to estimate material holdup and distribution within unit operations. In simulated run-testing, NUMATH typically produced estimates within 5% of the measured inventories for uranium and within 8% of the measured inventories for thorium during steady-state process operation.

  6. Density Functional Study on A-Units Based on Thieno[3,4- c]pyrrole-4,6-dione for Organic Solar Cells

    Science.gov (United States)

    Tang, Xiaoqin; Shen, Wei; Fu, Zhiyong; Liu, Xiaorui; Li, Ming

    2017-08-01

    The use of polymer donor materials has allowed great progress in organic solar cells. To search for potential donor materials, we have designed a series of donor-acceptor (D-A)-type alternating polymers composed of dithieno[3,2- b:2',3'- d]pyrrole (DTP) electron-rich units and thieno[3,4- c]pyrrole-4,6-dione (TPD) electron-deficient units. Their electronic and optical properties have been investigated using density functional theory and Marcus theory. The calculation results demonstrate that introduction of cyclic compounds (furyl, thienyl, and phenyl) into electron-deficient units of the molecules can result in lower highest occupied molecular orbital (HOMO) levels and reorganization energies compared with the experimental molecule ( X 0 ). To investigate the effects of electron-withdrawing units, three electron-withdrawing substituents (-OCH3, -F, and -CN) were introduced into the thienyl. The results indicated that the polymer X 2-3 will show the best performance among the designed polymers, offering low-lying HOMO energy level (-5.47 eV), narrow energy gap (1.97 eV), and high hole mobility (7.45 × 10-2 cm2 V-1 s-1). This work may provide a guideline for the design of efficient D-A polymers for organic solar cells with enhanced performance.

  7. Sustainable Materials Management (SMM) - Materials and Waste Management in the United States Key Facts and Figures

    Data.gov (United States)

    U.S. Environmental Protection Agency — Each year EPA produces a report called Advancing Sustainable Materials Management: Facts and Figures. It includes information on municipal solid waste (MSW)...

  8. In-situ Production of High Density Polyethylene and Other Useful Materials on Mars

    Science.gov (United States)

    Flynn, Michael

    2005-01-01

    This paper describes a revolutionary materials structure and power storage concept based on the in-situ production of abiotic carbon 4 compounds. One of the largest single mass penalties required to support the human exploration of Mars is the surface habitat. This proposal will use physical chemical technologies to produce high density polyethylene (HDPE) inflatable structures and construction materials from Mars atmospheric CO2. The formation of polyethylene from Mars CO2 is based on the use of the Sabatier and modified Fischer Tropsch reactions. The proposed system will fully integrate with existing in-situ propellant production concepts. The technology will also be capable of supplementing human caloric requirements, providing solid and liquid fuels for energy storage, and providing significant reduction in mission risk. The NASA Mars Reference Mission Definition Team estimated that a conventional Mars surface habitat structure would weigh 10 tonnes. It is estimated that this technology could reduce this mass by 80%. This reduction in mass will significantly contribute to the reduction in total mission cost need to make a Mars mission a reality. In addition the potential reduction of risk provided by the ability to produce C4 and potentially higher carbon based materials in-situ on Mars is significant. Food, fuel, and shelter are only three of many requirements that would be impacted by this research.

  9. In-situ Production of High Density Polyethylene and Other Useful Materials on Mars

    Science.gov (United States)

    Flynn, Michael

    2005-01-01

    This paper describes a revolutionary materials structure and power storage concept based on the in-situ production of abiotic carbon 4 compounds. One of the largest single mass penalties required to support the human exploration of Mars is the surface habitat. This proposal will use physical chemical technologies to produce high density polyethylene (HDPE) inflatable structures and construction materials from Mars atmospheric CO2. The formation of polyethylene from Mars CO2 is based on the use of the Sabatier and modified Fischer Tropsch reactions. The proposed system will fully integrate with existing in-situ propellant production concepts. The technology will also be capable of supplementing human caloric requirements, providing solid and liquid fuels for energy storage, and providing significant reduction in mission risk. The NASA Mars Reference Mission Definition Team estimated that a conventional Mars surface habitat structure would weigh 10 tonnes. It is estimated that this technology could reduce this mass by 80%. This reduction in mass will significantly contribute to the reduction in total mission cost need to make a Mars mission a reality. In addition the potential reduction of risk provided by the ability to produce C4 and potentially higher carbon based materials in-situ on Mars is significant. Food, fuel, and shelter are only three of many requirements that would be impacted by this research.

  10. Molecular Design for High Energy Density Materials%高能量密度材料的分子设计

    Institute of Scientific and Technical Information of China (English)

    董喜城; 陈敏伯

    2000-01-01

    CERIUS2 program was employed on an Indigo2 SGI workstation to investigate the vacuum and crystal structures of the high energy density materials (HEDM). Over 20 known HEDM were first studied with an emphasis on the enthalpy of formation, optimal lattice forms, crystal lattice energy and crystal density. On the basis of the study, about 20 potential HEDM were designed.

  11. Density measurements as a condition monitoring approach for following the aging of nuclear power plant cable materials

    Science.gov (United States)

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

    1999-10-01

    Monitoring changes in material density has been suggested as a potentially useful condition monitoring (CM) method for following the aging of cable jacket and insulation materials in nuclear power plants. In this study, we compare density measurements and ultimate tensile elongation results versus aging time for most of the important generic types of commercial nuclear power plant cable materials. Aging conditions, which include thermal-only, as well as combined radiation plus thermal, were chosen such that potentially anomalous effects caused by diffusion-limited oxidation (DLO) are unimportant. The results show that easily measurable density increases occur in most important cable materials. For some materials and environments, the density change occurs at a fairly constant rate throughout the mechanical property lifetime. For cases involving so-called induction-time behavior, density increases are slow to moderate until after the induction time, at which point they begin to increase dramatically. In other instances, density increases rapidly at first, then slows down. The results offer strong evidence that density measurements, which reflect property changes under both radiation and thermal conditions, could represent a very useful CM approach.

  12. HEAT STORAGE SYSTEM WITH PHASE CHANGE MATERIALS IN COGENERATION UNITS: STUDY OF PRELIMINARY MODEL

    Directory of Open Access Journals (Sweden)

    Claudio Caprara

    2008-12-01

    Full Text Available The continuous increase in the mechanization of farm activities, the rise in fuel prices and the environmental aspects concerning gas emissions are the main driving forces behind efforts toward more effective use of renewable energy sources and cogeneration systems even in agricultural and cattle farms. Nevertheless these systems are still not very suitable for this purpose because of their little flexibility in following the changing energy demand as opposed to the extremely various farm load curves, both in daytime and during the year. In heat recovery systems, the available thermal energy supply is always linked to power production, thus it does not usually coincide in time with the heat demand. Hence some form of thermal energy storage (TES is necessary in order to reach the most effective utilization of the energy source. This study deals with the modelling of a packed bed latent heat TES unit, integrating a cogeneration system made up of a reciprocating engine. The TES unit contains phase change materials (PCMs filled in spherical capsules, which are packed in an insulated cylindrical storage tank. Water is used as heat transfer fluid (HTF to transfer heat from the tank to the final uses, and exhausts from the engine are used as thermal source. PCMs are considered especially for their large heat storage capacity and their isothermal behaviour during the phase change processes. Despite their high energy storage density, most of them have an unacceptably low thermal conductivity, hence PCMs encapsulation technique is adopted in order to improve heat transfer. The special modular configuration of heat exchange tubes and the possibility of changing water flow through them allow to obtain the right amount of thermal energy from the tank, according to the hourly demand of the day. The model permits to choose the electrical load of the engine, the dimensions of the tank and the spheres, thickness and diameter of heat exchanger and the nature of

  13. Predicting critical temperatures of iron(II) spin crossover materials: density functional theory plus U approach.

    Science.gov (United States)

    Zhang, Yachao

    2014-12-07

    A first-principles study of critical temperatures (T(c)) of spin crossover (SCO) materials requires accurate description of the strongly correlated 3d electrons as well as much computational effort. This task is still a challenge for the widely used local density or generalized gradient approximations (LDA/GGA) and hybrid functionals. One remedy, termed density functional theory plus U (DFT+U) approach, introduces a Hubbard U term to deal with the localized electrons at marginal computational cost, while treats the delocalized electrons with LDA/GGA. Here, we employ the DFT+U approach to investigate the T(c) of a pair of iron(II) SCO molecular crystals (α and β phase), where identical constituent molecules are packed in different ways. We first calculate the adiabatic high spin-low spin energy splitting ΔE(HL) and molecular vibrational frequencies in both spin states, then obtain the temperature dependent enthalpy and entropy changes (ΔH and ΔS), and finally extract T(c) by exploiting the ΔH/T - T and ΔS - T relationships. The results are in agreement with experiment. Analysis of geometries and electronic structures shows that the local ligand field in the α phase is slightly weakened by the H-bondings involving the ligand atoms and the specific crystal packing style. We find that this effect is largely responsible for the difference in T(c) of the two phases. This study shows the applicability of the DFT+U approach for predicting T(c) of SCO materials, and provides a clear insight into the subtle influence of the crystal packing effects on SCO behavior.

  14. Ab-initio simulations of materials using VASP: Density-functional theory and beyond.

    Science.gov (United States)

    Hafner, Jürgen

    2008-10-01

    During the past decade, computer simulations based on a quantum-mechanical description of the interactions between electrons and between electrons and atomic nuclei have developed an increasingly important impact on solid-state physics and chemistry and on materials science-promoting not only a deeper understanding, but also the possibility to contribute significantly to materials design for future technologies. This development is based on two important columns: (i) The improved description of electronic many-body effects within density-functional theory (DFT) and the upcoming post-DFT methods. (ii) The implementation of the new functionals and many-body techniques within highly efficient, stable, and versatile computer codes, which allow to exploit the potential of modern computer architectures. In this review, I discuss the implementation of various DFT functionals [local-density approximation (LDA), generalized gradient approximation (GGA), meta-GGA, hybrid functional mixing DFT, and exact (Hartree-Fock) exchange] and post-DFT approaches [DFT + U for strong electronic correlations in narrow bands, many-body perturbation theory (GW) for quasiparticle spectra, dynamical correlation effects via the adiabatic-connection fluctuation-dissipation theorem (AC-FDT)] in the Vienna ab initio simulation package VASP. VASP is a plane-wave all-electron code using the projector-augmented wave method to describe the electron-core interaction. The code uses fast iterative techniques for the diagonalization of the DFT Hamiltonian and allows to perform total-energy calculations and structural optimizations for systems with thousands of atoms and ab initio molecular dynamics simulations for ensembles with a few hundred atoms extending over several tens of ps. Applications in many different areas (structure and phase stability, mechanical and dynamical properties, liquids, glasses and quasicrystals, magnetism and magnetic nanostructures, semiconductors and insulators, surfaces

  15. Use of raw materials in the United States from 1900 through 2014

    Science.gov (United States)

    Matos, Grecia R.

    2017-08-22

    The economic growth of an industrialized nation such as the United States requires raw materials for construction (buildings, bridges, highways, and so forth), defense, and processing and manufacture of goods and services. Since the beginning of the 20th century, the types and quantities of raw materials used have increased and changed significantly. This fact sheet quantifies the amounts of raw materials (other than food and fuel) that have been used in the U.S. economy annually for a period of 115 years, from 1900 through 2014. It provides a broad overview of the quantity (weight) of nonfood and nonfuel materials used in the economy and illustrates the use and significance of raw nonfuel minerals in particular as building blocks of society.These data have been compiled to help the public and policymakers understand the changing annual flow of raw materials put into use in the United States. Such information can be helpful in assessing the potential effects of materials use on the environment, assessing materials’ intensity of use, and examining the role that these materials play in the economy. The data presented indicate the substitution and shift in materials usage from renewable to nonrenewable materials during the 20th century. The disaggregated quantities by commodity (not shown in this fact sheet) may be tested against supply adequacy and end of life issues.

  16. Photoelectron spectroscopy and density functional theory studies of N-rich energetic materials.

    Science.gov (United States)

    Zeng, Zhen; Bernstein, Elliot R

    2016-10-28

    The geometric and electronic structures of molecular anionic energetic materials (EMs) DAAF (3,3'-diamino-4,4'-azoxyfurazan), FOX-7 (1,1-diamino-2,2-dinitroethene), 5,5'-BT (5,5'-bistetrazole), and 1,5'-BT (1,5'-bistetrazole) are explored employing anionic photoelectron spectroscopy and density functional theory calculations. The electron binding energies of the observed anionic, energetic material related species are determined and their corresponding anionic structures are assigned. Decomposition reactions for negatively charged EMs can proceed with different energy barriers, and thus mechanisms, from those for their related neutral EMs. Reactivity based on the anionic initial fragments of these EM species further reinforces their respective highly reactive and explosive nature. Fragment ions of the form EM(-)-H-X (X = N2, N2+NH, …) are additionally observed. Detection of such species suggests that EM(-)-H could serve as promising new candidates for EMs, assuming that such species are synthetically available, perhaps as energetic salts. Vertical detachment energies for transitions to the ground and first triplet electronic excited states of neutral matrix dye anion DCM(-) are additionally determined.

  17. Thermo-mechanical characterisation of low density carbon foams and composite materials for the ATLAS upgrade

    CERN Document Server

    Isaac, Bonad

    As a result of the need to increase the luminosity of the Large Hadron Collider (LHC) at CERN-Geneva by 2020, the ATLAS detector requires an upgraded inner tracker. Up- grading the ATLAS experiment is essential due to higher radiation levels and high particle occupancies. The design of this improved inner tracker detector involves development of silicon sensors and their support structures. These support structures need to have well un- derstood thermal properties and be dimensionally stable in order to allow efficient cooling of the silicon and accurate track reconstruction. The work presented in this thesis is an in- vestigation which aims to qualitatively characterise the thermal and mechanical properties of the materials involved in the design of the inner tracker of the ATLAS upgrade. These materials are silicon carbide foam (SiC foam), low density carbon foams such as PocoFoam and Allcomp foam, Thermal Pyrolytic Graphite (TPG), carbon/carbon and Carbon Fibre Re- inforced Polymer (CFRP). The work involve...

  18. Photoelectron spectroscopy and density functional theory studies of N-rich energetic materials

    Science.gov (United States)

    Zeng, Zhen; Bernstein, Elliot R.

    2016-10-01

    The geometric and electronic structures of molecular anionic energetic materials (EMs) DAAF (3,3'-diamino-4,4'-azoxyfurazan), FOX-7 (1,1-diamino-2,2-dinitroethene), 5,5'-BT (5,5'-bistetrazole), and 1,5'-BT (1,5'-bistetrazole) are explored employing anionic photoelectron spectroscopy and density functional theory calculations. The electron binding energies of the observed anionic, energetic material related species are determined and their corresponding anionic structures are assigned. Decomposition reactions for negatively charged EMs can proceed with different energy barriers, and thus mechanisms, from those for their related neutral EMs. Reactivity based on the anionic initial fragments of these EM species further reinforces their respective highly reactive and explosive nature. Fragment ions of the form EM--H-X (X = N2, N2+NH, …) are additionally observed. Detection of such species suggests that EM--H could serve as promising new candidates for EMs, assuming that such species are synthetically available, perhaps as energetic salts. Vertical detachment energies for transitions to the ground and first triplet electronic excited states of neutral matrix dye anion DCM- are additionally determined.

  19. Effect of expanded graphite on the phase change materials of high density polyethylene/wax blends

    Energy Technology Data Exchange (ETDEWEB)

    AlMaadeed, M.A., E-mail: m.alali@qu.edu.qa [Center for Advanced Materials, Qatar University, 2713 Doha (Qatar); Labidi, Sami [Center for Advanced Materials, Qatar University, 2713 Doha (Qatar); Krupa, Igor [QAPCO Polymer Chair, Center for Advanced Materials, Qatar University, P.O. Box 2713, Doha (Qatar); Karkri, Mustapha [Université Paris-Est CERTES, 61 avenue du Général de Gaulle, 94010 Créteil (France)

    2015-01-20

    Highlights: • Expanded graphite (EG) and low melting point (42.3 °C) wax were added to HDPE to form phase change material. • EG was well dispersed in the composites and did not affect the melting or crystallization of the HDPE matrix. • EG increased the thermal stability of the composites by reducing chain mobility and inhibiting degradation. • The addition of a relatively small quantity of EG enhances the heat conduction in the composite. • HDPE/40% RT42 that contained up to 15% EG demonstrated excellent mechanical and thermal properties and can be used as PCM. - Abstract: Phase change materials fabricated from high density polyethylene (HDPE) blended with 40 or 50 wt% commercial wax (melting point of 43.08 °C) and up to 15 wt% expanded graphite (EG) were studied. Techniques including scanning electron microscope (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and an experimental device to measure diffusivity and conductivity (DICO) were used to determine the microstructural, mechanical and thermal properties of the composites. The composites possessed good mechanical properties. Additionally, no leaching was observed during material processing or characterization. Although the Young’s modulus increased with the addition of EG, no significant changes in tensile strength were detected. The maximum Young’s modulus achieved was 650 MPa for the HDPE/40% wax composite with 15 wt% EG. The EG was well dispersed within the composites and did not affect the melting or crystallization of the HDPE matrix. The incorporation of EG increased the thermal stability of the composites by reducing chain mobility and inhibiting degradation. The intensification of thermal conductivity occurred with increasing fractions of EG, which was attributed to the high thermal conductivity of graphite. The maximum quantity of heat stored by latent heat was found for the HDPE/40% wax composite with EG. The addition of a relatively small quantity

  20. The mineralogy and chemistry of cement and cement raw materials In the united arab emirates

    OpenAIRE

    Nasir, Sobhi J. [صبحي جابر نصر; El Etr, H.

    1996-01-01

    The raw materials, clinkers and cements from different cement factories in the United Arab Emirates have been investigated using polarizing microscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM), and chemical analyses. The chemical and mineralogical analyses indicate that the local raw materials are suitable for cement industry. Geological review shows that there is a good potential for industrial-grade local occurrences of limestone, marl, gypsum and iron oxide, that may be ...

  1. Attributes for NHDplus Catchments (Version 1.1) for the Conterminous United States: Population Density, 2000

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the average population density, in number of people per square kilometer multiplied by 10 for the year 2000, compiled for every catchment of...

  2. 2000 population density by block group for the conterminous United States

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents 2000 population density by block group as a 100-m grid using data from the 2000 Census of Population and Housing. The demographic data is...

  3. 1990 population density by block group for the conterminous United States

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents 1990 population density by block group as a 100-m grid using data from the 1990 Census of Population and Housing (Public Law 94-171...

  4. Calculation of polarization and bound charge density inside a dielectric material in triboelectric nanogenerators: Analytical and numerical study

    Science.gov (United States)

    Kim, SeongMin; Ha, Jaewook; Kim, Jin-Baek

    2016-11-01

    We analytically calculated polarization and bound charge density inside the dielectric material in metal-to-dielectric-mode triboelectric nanogenerators (TENG) where the transferred charges are collected on the bottom metal via electrostatic induction from the triboelectric charges that are generated by frictional contact. This bound charge density is associated with the surface density of states (DOS), overline{Ns(E)}. Two cases are considered here: i) for overline{Ns(E)} ≫ 1, it is calculated that the bound charge density is proportional to the dielectric constant and the work function difference between the two materials, but inversely proportional to the thickness of the dielectric material (ɛ0(ɛ2-1) (E0-W)/e \\cdot d2); ii) for overline{Ns(E)} ≪ 1 with constant overline{Ns(E)}, the bound charge density is mostly proportional to the work function difference between the materials, and inversely proportional to the thickness of the dielectric material ((ɛ2-1)x/d_{2+\\varepsilon2\\cdot x} \\cdot Ns(E)\\cdot e\\cdot (E0-W)).

  5. Corn Production. A Unit for Teachers of Vocational Agriculture. Production Agriculture Curriculum Materials Project.

    Science.gov (United States)

    Grace, Clyde, Jr.

    Designed to provide instructional materials for use by vocational agriculture teachers, this unit contains nine lessons based upon competencies needed to maximize profits in corn production. The lessons cover opportunities for growing corn; seed selection; seedbed preparation; planting methods and practices; fertilizer rates and application;…

  6. 3D-Printing Crystallographic Unit Cells for Learning Materials Science and Engineering

    Science.gov (United States)

    Rodenbough, Philip P.; Vanti, William B.; Chan, Siu-Wai

    2015-01-01

    Introductory materials science and engineering courses universally include the study of crystal structure and unit cells, which are by their nature highly visual 3D concepts. Traditionally, such topics are explored with 2D drawings or perhaps a limited set of difficult-to-construct 3D models. The rise of 3D printing, coupled with the wealth of…

  7. 3D-Printing Crystallographic Unit Cells for Learning Materials Science and Engineering

    Science.gov (United States)

    Rodenbough, Philip P.; Vanti, William B.; Chan, Siu-Wai

    2015-01-01

    Introductory materials science and engineering courses universally include the study of crystal structure and unit cells, which are by their nature highly visual 3D concepts. Traditionally, such topics are explored with 2D drawings or perhaps a limited set of difficult-to-construct 3D models. The rise of 3D printing, coupled with the wealth of…

  8. Ecologia: Spanish Ecology Packet Resource Units and Materials for Intermediate and Advanced Spanish Classes.

    Science.gov (United States)

    Bell, Mozelle Sawyer; Arribas, E. Jaime

    This Spanish ecology packet contains resource units and materials for intermediate and advanced Spanish classes. It is designed to be used for individual and small-group instruction in the senior high school to supplement the Spanish language curriculum. Included are articles, pictures, and cartoons from Spanish-language newspapers and magazines…

  9. High-density EEG coherence analysis using functional units applied to mental fatigue

    NARCIS (Netherlands)

    Caat, Michael ten; Lorist, Monicque M.; Bezdan, Eniko; Roerdink, Jos B.T.M.; Maurits, Natasha M.

    2008-01-01

    Electroencephalography (EEG) coherence provides a quantitative measure of functional brain connectivity which is calculated between pairs of signals as a function of frequency. Without hypotheses, traditional coherence analysis would be cumbersome for high-density EEG which employs a large number of

  10. Bone density: comparative evaluation of Hounsfield units in multislice and cone-beam computed tomography

    Directory of Open Access Journals (Sweden)

    Isabela Maria de Carvalho Crusoé Silva

    2012-12-01

    Full Text Available The aim of this study was to evaluate the validity of the bone density value of potential implant sites in HU obtained by a specific cone-beam computed tomography (CBCT device. In this study, the HU values obtained using a MSCT scanner were used as the gold standard. Twenty mandibles (40 potential implant sites were scanned using an MSCT scanner (Somatom Sensation 40 and a CBCT scanner (i-CAT. The MSCT images were evaluated using the Syngo CT Workplace software and the CBCT images, using the XoranCat software. The images were evaluated twice by three oral radiologists, at 60 day intervals. The trabecular bone density of the same area was evaluated on both images. Intraclass coefficients (ICC were calculated to examine the agreement between the examiners and between the two periods of evaluation. The bone density and area of the ROI were compared by the Student t test and Bland-Altman analysis. ICCs were excellent. The mean HU value obtained using CBCT (418.06 was higher than that obtained using MSCT (313.13, with a statistically significant difference (p < 0.0001. In addition, Bland-Altman analysis showed that the HU measures were not equivalent. In conclusion, the bone density in HU with CBCT images obtained using the device studied proved unreliable, since it was higher than that obtained using MSCT.

  11. High-density EEG coherence analysis using functional units applied to mental fatigue

    NARCIS (Netherlands)

    Caat, Michael ten; Lorist, Monicque M.; Bezdan, Eniko; Roerdink, Jos B.T.M.; Maurits, Natasha M.

    2008-01-01

    Electroencephalography (EEG) coherence provides a quantitative measure of functional brain connectivity which is calculated between pairs of signals as a function of frequency. Without hypotheses, traditional coherence analysis would be cumbersome for high-density EEG which employs a large number of

  12. Analysis of Interface Charge Densities for High-k Dielectric Materials based Metal Oxide Semiconductor Devices

    Science.gov (United States)

    Maity, N. P.; Thakur, R. R.; Maity, Reshmi; Thapa, R. K.; Baishya, S.

    2016-10-01

    In this paper, the interface charge densities (Dit) are studied and analyzed for ultra thin dielectric metal oxide semiconductor (MOS) devices using different high-k dielectric materials such as Al2O3, ZrO2 and HfO2. The Dit have been calculated by a new approach using conductance method and it indicates that by reducing the thickness of the oxide, the Dit increases and similar increase is also found by replacing SiO2 with high-k. For the same oxide thickness, SiO2 has the lowest Dit and found to be the order of 1011cm-2eV-1. Linear increase in Dit has been observed as the dielectric constant of the oxide increases. The Dit is found to be in good agreement with published fabrication results at p-type doping level of 1×1017cm-3. Numerical calculations and solutions are performed by MATLAB and device simulation is done by ATLAS.

  13. On Materiality and Dimensionality of the Space. Is There Some Unit of the Field?

    Directory of Open Access Journals (Sweden)

    Belyakov A. V.

    2014-10-01

    Full Text Available The article presents arguments with a view to recognize that space is material and has possibly a fractal dimension in the range of from three to two. It is proposed that along to the unit of substance (atom Some Unit of the field (vortex tubes should be set. It is shown that the formation of the field structures being a kind “ doubles” of atomic ones is possible. The existence of the three-zone electron structure is confirmed. It is indicated that this concept have already resulted in to the successful explanation of phenomena and to finding of their important parameters at different levels of the organization of matter.

  14. Density functional theory based tight binding study on theoretical prediction of low-density nanoporous phases ZnO semiconductor materials

    Science.gov (United States)

    Tuoc, Vu Ngoc; Doan Huan, Tran; Viet Minh, Nguyen; Thi Thao, Nguyen

    2016-06-01

    Polymorphs or phases - different inorganic solids structures of the same composition usually have widely differing properties and applications, thereby synthesizing or predicting new classes of polymorphs for a certain compound is of great significance and has been gaining considerable interest. Herein, we perform a density functional theory based tight binding (DFTB) study on theoretical prediction of several new phases series of II-VI semiconductor material ZnO nanoporous phases from their bottom-up building blocks. Among these, three phases are reported for the first time, which could greatly expand the family of II- VI compound nanoporous phases. We also show that all these generally can be categorized similarly to the aluminosilicate zeolites inorganic open-framework materials. The hollow cage structure of the corresponding building block ZnkOk (k= 9, 12, 16) is well preserved in all of them, which leads to their low-density nanoporous and high flexibility. Additionally the electronic wide-energy gap of the individual ZnkOk is also retained. Our study reveals that they are all semiconductor materials with a large band gap. Further, this study is likely to be the common for II-VI semiconductor compounds and will be helpful for extending their range of properties and applications.

  15. Hounsfield units variations. Impact on CT-density based conversion tables and their effects on dose distribution

    Energy Technology Data Exchange (ETDEWEB)

    Zurl, B.; Winkler, P.; Kapp, K.S. [University Medical School of Graz, Comprehensive Cancer Center Graz, Department of Therapeutic Radiotherapy and Oncology, Graz (Austria); Tiefling, R.; Kindl, P. [University of Technology, Institute of Materials Physics, Graz (Austria)

    2014-01-15

    Determination of dose error margins in radiation therapy planning due to variations in Hounsfield Units (HU) values dependent on the use of different CT scanning protocols. Based on a series of different CT scanning protocols used in clinical practice, conversion tables for radiation dose calculations were generated and subsequently tested on a phantom. These tables were then used to recalculate the radiation therapy plans of 28 real patients after an incorrect scanning protocol had inadvertently been used for these patients. Different CT parameter settings resulted in errors of HU values of up to 2.6 % for densities of < 1.1 g/cm{sup 3}, but up to 25.6 % for densities of > 1.1 g/cm{sup 3}. The largest errors were associated with changes in the tube voltage. Tests on a virtual water phantom with layers of variable thickness and density revealed a sawtooth-shaped curve for the increase of dose differences from 0.3 to 0.6 % and 1.5 % at layer thicknesses of 1, 3, and 7 cm, respectively. Use of a beam hardening filter resulted in a reference dose difference of 0.6 % in response to a density change of 5 %. The recalculation of data from 28 patients who received radiation therapy to the head revealed an overdose of 1.3 ± 0.4 % to the bone and 0.7 ± 0.1 % to brain tissue. On average, therefore, one monitor unit (range 0-3 MU) per 100 MU more than the correct dose had been given. Use of different CT scanning protocols leads to variations of up to 20 % in the HU values. This can result in a mean systematic dose error of 1.5 %. Specific conversion tables and automatic CT scanning protocol recognition could reduce dose errors of these types. (orig.)

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

    Science.gov (United States)

    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. A Room to Grow: The Residential Density-Dependence of Childbearing in Europe and the United States

    Directory of Open Access Journals (Sweden)

    Nathanael Lauster

    2010-12-01

    produce new density-dependent fertility dynamics. In particular, childbearing becomes dependent upon residential roominess. This relationship is culturally specific, and that the cultural nature of this relationship means that professional and managerial classes are likely to be particularly influenced by residential roominess, while immigrants are less likely to be influenced. Hypotheses are tested linking residential roominess to the presence of an “own infant” in the household using census data from the Austria, Greece, Portugal, Spain, and the United States. Roominess predicts fertility in all countries, but to differing degrees.

  18. A Room to Grow: The Residential Density-dependence of Childbearing in Europe and the United States

    Directory of Open Access Journals (Sweden)

    Nathanael Lauster

    2010-01-01

    Full Text Available I argue that cultural processes linked to the demographic transition produce new density-dependent fertility dynamics. In particular, childbearing becomes dependent upon residential roominess. This relationship is culturally specific, and I argue that the cultural nature of this relationship means that professional and managerial classes are likely to be particularly influenced by residential roominess, while immigrants are less likely to be influenced. I test hypotheses linking residential roominess to the presence of an “own infant” in the household using census data from the Austria, Greece, Portugal, Spain, and the United States. Roominess predicts fertility in all countries, but to differing degrees.

  19. Low-Density and High Porosity Hydrogen Storage Materials Built from Ultra-Light Elements. Final Scientific/Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Pingyun [Univ. of California, Riverside, CA (United States)

    2014-01-10

    A number of significant advances have been achieved, opening up new opportunities for the synthetic development of novel porous materials and their energy-related applications including gas storage and separation and catalysis. These include lithium-based metal-organic frameworks, magnesium-based metal-organic frameworks, and high gas uptake in porous frameworks with high density of open donor sites.

  20. Multiple unit gastroretentive drug delivery systems: a new preparation method for low density microparticles.

    Science.gov (United States)

    Streubel, A; Siepmann, J; Bodmeier, R

    2003-01-01

    The aim of this study was to develop a new preparation method for low density foam-based, floating microparticles and to demonstrate the systems' performance in vitro. Major advantages of the novel preparation technique include: (i) short processing times, (ii) no exposure of the ingredients to high temperatures, (iii) the possibility to avoid toxic organic solvents, and (iv) high encapsulation efficiencies close to 100%. Floating microparticles consisting of polypropylene foam powder, model drug [chlorpheniramine maleate (CPM), diltiazem HCl, theophylline or verapamil HCl] and polymer [Eudragit RS or polymethyl methacrylate (PMMA)] were prepared by soaking the microporous foam carrier with an organic solution of drug and polymer and subsequent drying. The effects of various formulation and processing parameters on the resulting in vitro floating behaviour, internal and external particle morphology, drug loading, in vitro drug release and physical state of the incorporated drug were studied. Good in vitro floating behaviour was observed in most cases and a broad variety of drug release patterns could be achieved by varying the drug loading and type of polymer. Interestingly, PMMA-based microparticles showed incomplete drug release with verapamil HCl. This restriction could be overcome by forming the free base of the drug prior to microparticle preparation. In contrast to the salt, the free base acted as a plasticizer for PMMA, resulting in sufficiently high diffusion coefficients and, consequently, complete drug release. The low density microparticles were compressed into rapidly disintegrating tablets in order to provide an administrable oral dosage form.

  1. A flexible and high-voltage internal tandem supercapacitor based on graphene-based porous materials with ultrahigh energy density.

    Science.gov (United States)

    Zhang, Fan; Lu, Yanhong; Yang, Xi; Zhang, Long; Zhang, Tengfei; Leng, Kai; Wu, Yingpeng; Huang, Yi; Ma, Yanfeng; Chen, Yongsheng

    2014-06-12

    Pursuing higher working voltage and packaged energy density, an internal tandem supercapacitor has been successfully designed and fabricated based on graphene-based porous carbon hybrid material. Compared with the packaged energy density of 27.2 Wh kgcell (-1) and working voltage of 3.5 V using EMIMBF4 electrolyte for the conventional single-cell supercapacitor, the internal tandem device with the same material achieves a much higher working voltage of 7 V as well as a significantly improved energy density of 36.3 Wh kgcell (-1) (increased by 33%), which is also about 7 times of that of the state-of-art commercial supercapacitors. A flexible internal tandem device is also designed and fabricated and demonstrated similar excellent performance.

  2. Hounsfield Unit inaccuracy in computed tomography lesion size and density, diagnostic quality vs attenuation correction

    Science.gov (United States)

    Szczepura, Katy; Thompson, John; Manning, David

    2017-03-01

    In computed tomography the Hounsfield Units (HU) are used as an indicator of the tissue type based on the linear attenuation coefficients of the tissue. HU accuracy is essential when this metric is used in any form to support diagnosis. In hybrid imaging, such as SPECT/CT and PET/CT, the information is used for attenuation correction (AC) of the emission images. This work investigates the HU accuracy of nodules of known size and HU, comparing diagnostic quality (DQ) images with images used for AC.

  3. Use of raw materials in the United States from 1900 through 2010

    Science.gov (United States)

    Matos, Grecia R.

    2012-01-01

    Since the beginning of the 20th century, the types and quantities of raw materials used by U.S. manufacturers and consumers have changed over time. This fact sheet quantifies the amounts of those materials (other than food and fuel) that have been input into the U.S. economy annually for a period of 111 years, from 1900 through 2010. It provides a broad overview of all materials used but highlights the use and importance of raw nonfuel minerals in particular. This fact sheet supersedes U.S. Geological Survey Fact Sheet 2009–3008, which was published in April 2009 and covered the period 1900 through 2006. These data have been compiled to help the public and policymakers understand the flow of raw materials used in the United States in physical terms. Such information can be helpful in assessing the past and potential effects of the materials on the environment, evaluating the materials’ intensity of use, and examining the role that these materials play in the economy. It can also provide insight into what may happen to the materials at the end of their useful life.

  4. Unit-Sphere Multiaxial Stochastic-Strength Model Applied to Anisotropic and Composite Materials

    Science.gov (United States)

    Nemeth, Noel, N.

    2013-01-01

    Models that predict the failure probability of brittle materials under multiaxial loading have been developed by authors such as Batdorf, Evans, and Matsuo. These "unit-sphere" models assume that the strength-controlling flaws are randomly oriented, noninteracting planar microcracks of specified geometry but of variable size. This methodology has been extended to predict the multiaxial strength response of transversely isotropic brittle materials, including polymer matrix composites (PMCs), by considering (1) flaw-orientation anisotropy, whereby a preexisting microcrack has a higher likelihood of being oriented in one direction over another direction, and (2) critical strength, or K (sub Ic) orientation anisotropy, whereby the level of critical strength or fracture toughness for mode I crack propagation, K (sub Ic), changes with regard to the orientation of the microstructure. In this report, results from finite element analysis of a fiber-reinforced-matrix unit cell were used with the unit-sphere model to predict the biaxial strength response of a unidirectional PMC previously reported from the World-Wide Failure Exercise. Results for nuclear-grade graphite materials under biaxial loading are also shown for comparison. This effort was successful in predicting the multiaxial strength response for the chosen problems. Findings regarding stress-state interactions and failure modes also are provided.

  5. Dual-energy X-ray absorptiometry for the simultaneous determination of Density and Moisture Content in Porous Structural Materials

    DEFF Research Database (Denmark)

    Hansen, Kurt Kielsgaard; Jensen, Signe Kamp; Gerward, Leif

    1999-01-01

    The paper describes the dual-energy x-ray equipment, which consists of a x-ray source, filters and a detector. The x-ray beam can be moved automatically in two dimensions relative to a fixed specimen. The purpose of the equipment is to measure simultaneously the density and moisture content......-ray measurements show good agreement with results from the two standard materials which imitate water in a porous material. On this background the dual-energy x-ray absorptiometry measurement principle can be used on porous structural materials....

  6. Environmental risk assessment of low density polyethylene unit using the method of failure mode and effect analysis

    Directory of Open Access Journals (Sweden)

    Salati Parinaz

    2012-01-01

    Full Text Available The ninth olefin plan of Arya Sasol Petrochemical Company (A.S.P.C. is regarded the largest gas Olefin Unit located on Pars Special Economic Energy Zone (P.S.E.E.Z. Considering the importance of the petrochemical unit, its environmental assessment seems necessary to identify and reduce potential hazards. For this purpose, after determining the scope of the study area, identification and measurement of the environmental parameters, environmental risk assessment of the unit was carried out using Environment Failure Mode and Effect Analysis (EFMEA. Using the noted method, sources causing environmental risks were identified, rated and prioritized. Beside, the impacts of the environmental aspects derived from the unit activities as well as their consequences were also analyzed. Furthermore, the identified impacts were prioritized based on Risk Priority Number (RPN and severity level of the consequences imposed on the affected environment. After performing statistical calculations, it was found that the environmental aspects owing the risk priority number higher than 15 have a high level of risk. Results obtained from Low Density Polyethylene Unit revealed that the highest risk belongs to the emergency vent system with risk priority number equal to 48. It is occurred due to imperfect performance of the reactor safety system leading to the emissions of ethylene gas, particles, and radioactive steam as well as air and noise pollutions. Results derived from secondary assessment of the environmental aspects, through difference in calculated RPN and activities risk levels showed that employing modern methods and risk assessment are have remarkably reduced the severity of risk and consequently detracted the damages and losses incurred on the environment.

  7. Effects of environmental covariates and density on the catchability of fish populations and interpretation of catch per unit effort trends

    Science.gov (United States)

    Korman, Josh; Yard, Mike

    2017-01-01

    Article for outlet: Fisheries Research. Abstract: Quantifying temporal and spatial trends in abundance or relative abundance is required to evaluate effects of harvest and changes in habitat for exploited and endangered fish populations. In many cases, the proportion of the population or stock that is captured (catchability or capture probability) is unknown but is often assumed to be constant over space and time. We used data from a large-scale mark-recapture study to evaluate the extent of spatial and temporal variation, and the effects of fish density, fish size, and environmental covariates, on the capture probability of rainbow trout (Oncorhynchus mykiss) in the Colorado River, AZ. Estimates of capture probability for boat electrofishing varied 5-fold across five reaches, 2.8-fold across the range of fish densities that were encountered, 2.1-fold over 19 trips, and 1.6-fold over five fish size classes. Shoreline angle and turbidity were the best covariates explaining variation in capture probability across reaches and trips. Patterns in capture probability were driven by changes in gear efficiency and spatial aggregation, but the latter was more important. Failure to account for effects of fish density on capture probability when translating a historical catch per unit effort time series into a time series of abundance, led to 2.5-fold underestimation of the maximum extent of variation in abundance over the period of record, and resulted in unreliable estimates of relative change in critical years. Catch per unit effort surveys have utility for monitoring long-term trends in relative abundance, but are too imprecise and potentially biased to evaluate population response to habitat changes or to modest changes in fishing effort.

  8. Determination of total mass attenuation coefficients, effective atomic numbers and electron densities for different shielding materials used in radiation protection

    Energy Technology Data Exchange (ETDEWEB)

    Almeida J, A. T. [FUNDACENTRO, Centro Regional de Minas Gerais, Brazilian Institute for Safety and Health at Work, Belo Horizonte, 30180-100 Minas Gerais (Brazil); Nogueira, M. S. [Center of Development of Nuclear Technology / CNEN, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil); Santos, M. A. P., E-mail: mnogue@cdtn.br [Regional Center for Nuclear Science / CNEN, 50.740-540 Recife, Pernambuco (Brazil)

    2015-10-15

    Full text: In this paper, the interaction of X-rays with some shielding materials has been studied for materials containing different amounts of barite and aggregates. The total mass attenuation coefficient (μ{sub t}) for three shielding materials has been calculated by using WinXCOM program in the energy range from RQR qualities (RQR-4, RQR-6, RQR-9, and RQR-10). They were: cream barite (density 2.99 g/cm{sup 3} collected in the State of Sao Paulo), purple barite (density 2.95 g/cm{sup 3} collected in the State of Bahia) and white barite (density 3.10 g/cm{sup 3} collected in the State of Paraiba). The chemical analysis was carried out by an X-ray fluorescence spectrometer model EDX-720, through dispersive energy. The six elements of the higher concentration found in the sample and analyzed by Spectrophotometry of Energy Dispersive X-ray for the samples were Ba(60.9% - white barite), Ca(17,92% - cream barite), Ce(3,60% - white barite), Fe(17,16% - purple barite), S(12,11% - white barite) and Si(29,61% - purple barite). Also, the effective atomic number (Z{sub eff}) and the effective electron density (N{sub eff}) were calculated using the values of the total mass attenuation coefficient. The dependence of these parameters on the incident photon energy and the chemical composition has been examined. (Author)

  9. Effect of raw material properties and die geometry on the density of biomass pellets from composted municipal solid waste

    Directory of Open Access Journals (Sweden)

    Abedin Zafari

    2012-11-01

    Full Text Available Densification of biomass feedstocks, such as pelletizing, can increase bulk density, improve storability, reduce transportation costs, and ease the handling of biomass using existing handling and storage equipment for grains. In order to study the pelletizing process, compost pellets were produced under controlled conditions. The aim of the work was to investigate the effect of raw material properties and the die geometry on the true density of formed pellets and also find the optimal conditions of the densification process for producing pellets with high density. Compost was extruded into cylindrical pellets utilizing open-end dies under axial stress from a vertical piston applied by a hydraulic press. The effects of independent variables, including the raw material moisture content (35 to 45% (wet basis, hammer mill screen size (0.3 to 1.5 mm, speed of piston (2 to 10 mm/s, and die length (8 to 12 mm on pellet density, were determined using response surface methodology. A quadratic model was proposed to predict the pellet density, which had high F and R2 values along with a low p value, indicating the predictability of the model. Moisture content, speed of piston, and particle size significantly affected (P 0.05.

  10. Research on high density and safety LiCoO2 as cathode materials for lithium ion batteries

    Institute of Scientific and Technical Information of China (English)

    CHEN; Yan-bin; LIU; Ya-fei; BAI; Hou-shan

    2005-01-01

    Three LiCoO2 samples of different specifications were synthesized using different Co3O4 s as starting material, and characterized in physical, electrochemical and safety properties. There demonstrates clear dependence of LiCoO2 on Co3O4 in particle size and density. The main difference among the three LiCoO2 samples lies in physical, rate capability and safety properties, the sample with larger particle size, higher density (accordingly smaller surface area) demonstrates better safety but lower rate capability, while there is little difference among them in terms of capacity and cycling stability despite of the variation in physical properties.

  11. Computational Design of Non-natural Sugar Alcohols to Increase Thermal Storage Density: Beyond Existing Organic Phase Change Materials.

    Science.gov (United States)

    Inagaki, Taichi; Ishida, Toyokazu

    2016-09-14

    Thermal storage, a technology that enables us to control thermal energy, makes it possible to reuse a huge amount of waste heat, and materials with the ability to treat larger thermal energy are in high demand for energy-saving societies. Sugar alcohols are now one promising candidate for phase change materials (PCMs) because of their large thermal storage density. In this study, we computationally design experimentally unknown non-natural sugar alcohols and predict their thermal storage density as a basic step toward the development of new high performance PCMs. The non-natural sugar alcohol molecules are constructed in silico in accordance with the previously suggested molecular design guidelines: linear elongation of a carbon backbone, separated distribution of OH groups, and even numbers of carbon atoms. Their crystal structures are then predicted using the random search method and first-principles calculations. Our molecular simulation results clearly demonstrate that the non-natural sugar alcohols have potential ability to have thermal storage density up to ∼450-500 kJ/kg, which is significantly larger than the maximum thermal storage density of the present known organic PCMs (∼350 kJ/kg). This computational study suggests that, even in the case of H-bonded molecular crystals where the electrostatic energy contributes mainly to thermal storage density, the molecular distortion and van der Waals energies are also important factors to increase thermal storage density. In addition, the comparison between the three eight-carbon non-natural sugar alcohol isomers indicates that the selection of preferable isomers is also essential for large thermal storage density.

  12. The StreamCat Dataset: Accumulated Attributes for NHDPlusV2 (Version 2.1) Catchments Riparian Buffer for the Conterminous United States: 2010 US Census Housing Unit and Population Density

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset represents the population and housing unit density within individual, local NHDPlusV2 catchments and upstream, contributing watersheds riparian buffers...

  13. The StreamCat Dataset: Accumulated Attributes for NHDPlusV2 Catchments (Version 2.1) for the Conterminous United States: 2010 US Census Housing Unit and Population Density

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset represents the population and housing unit density within individual, local NHDPlusV2 catchments and upstream, contributing watersheds based on 2010 US...

  14. [Achievement of low-density lipoprotein cholesterol therapeutic goal in lipid and vascular risk units of the Spanish Arteriosclerosis Society].

    Science.gov (United States)

    Pedro-Botet, Juan; Mostaza, José M; Pintó, Xavier; Banegas, José R

    2013-01-01

    To evaluate low-density lipoprotein-cholesterol (LDLc) goal achievement among dyslipidemic patients treated in lipid and vascular risk units of the Spanish Society of Arteriosclerosis (SEA). The LDLc goal was based on the 2007 European guidelines for cardiovascular prevention. Observational, longitudinal, retrospective, multicenter national study that included consecutive patients of both sexes over 18 years of age referred for dyslipidemia and cardiovascular risk. Information was collected from medical records corresponding to two visits in the lipid unit. We included 1,828 patients from 43 lipid units. In the initial visit, 846 (46.3%) patients were on lipid lowering drug treatment. On the follow-up there was a significant increase in the use of cholesterol-lowering agents, except for a decrease in the use of nicotinic acid. 65.3% of patients with vascular disease and 50.4% with diabetes achieved an LDLc level <100mg/dL. Overall, 44.7% of patients achieved the LDLc goal and the predictors in the multivariate analysis were age, waist circumference, diabetes and the presence of vascular disease. Dyslipidemic patients referred to SEA lipid units have improved LDLc goal achievement after follow-up compared with data reported from previous studies in other health care settings. This improvement was associated with a substantial increase in the prescription of statins, both in monotherapy and combined with ezetimibe. There is still a wide room for improvement in the effectiveness of hypercholesterolemia treatment. Copyright © 2013 Elsevier España, S.L. y SEA. All rights reserved.

  15. High-density 3D graphene-based monolith and related materials, methods, and devices

    Energy Technology Data Exchange (ETDEWEB)

    Worsley, Marcus A.; Baumann, Theodore F.; Biener, Juergen; Charnvanichborikarn, Supakit; Kucheyev, Sergei; Montalvo, Elizabeth; Shin, Swanee; Tylski, Elijah

    2017-03-21

    A composition comprising at least one high-density graphene-based monolith, said monolith comprising a three-dimensional structure of graphene sheets crosslinked by covalent carbon bonds and having a density of at least 0.1 g/cm.sup.3. Also provided is a method comprising: preparing a reaction mixture comprising a suspension and at least one catalyst, said suspension selected from a graphene oxide (GO) suspension and a carbon nanotube suspension; curing the reaction mixture to produce a wet gel; drying the wet gel to produce a dry gel, said drying step is substantially free of supercritical drying and freeze drying; and pyrolyzing the dry gel to produce a high-density graphene-based monolith. Exceptional combinations of properties are achieved including high conductive and mechanical properties.

  16. High-density 3D graphene-based monolith and related materials, methods, and devices

    Science.gov (United States)

    Worsley, Marcus A.; Baumann, Theodore F.; Biener, Juergen; Charnvanichborikarn, Supakit; Kucheyev, Sergei; Montalvo, Elizabeth; Shin, Swanee; Tylski, Elijah

    2017-03-21

    A composition comprising at least one high-density graphene-based monolith, said monolith comprising a three-dimensional structure of graphene sheets crosslinked by covalent carbon bonds and having a density of at least 0.1 g/cm.sup.3. Also provided is a method comprising: preparing a reaction mixture comprising a suspension and at least one catalyst, said suspension selected from a graphene oxide (GO) suspension and a carbon nanotube suspension; curing the reaction mixture to produce a wet gel; drying the wet gel to produce a dry gel, said drying step is substantially free of supercritical drying and freeze drying; and pyrolyzing the dry gel to produce a high-density graphene-based monolith. Exceptional combinations of properties are achieved including high conductive and mechanical properties.

  17. HoneySiC: a new optomechanical material for low-areal cost and density

    Science.gov (United States)

    Goodman, William A.

    2013-09-01

    One of the major problems perceived for deposited silicon carbide mirrors and structures is the cost associated with machining and lightweighting the material to the specifications of a drawing. Molded pedigrees of silicon carbide address these concerns by casting or molding a slurry and prefiring the slurry to make a consolidated and porous greenbody which is relatively soft and not very difficult to machine. The machined greenbody is then infiltrated with molten silicon in an exothermic process that yields a two phase reaction bonded silicon carbide material that must undergo a final machining step. Converted silicon carbide pedigrees machine a graphite or carbon/carbon precursor material to near net shape and then infiltrate the part with gaseous silicon monoxide or molten silicon to convert most or all of the carbon to silicon carbide. Some pedigrees are highly porous, while others may be dense and containing 2 or 3 different phases of material. We have created and demonstrated a new fiber reinforced silicon carbide material that combines the benefits of molding, infiltration and conversion processes. The resulting HoneySiC material requires a minimal amount of machining. HoneySiC material achieves lightweighting of 92% relative to bulk material and net production cost on the order of 38K per square meter (unpolished), less than half of NASA's goal of 100K per square meter.

  18. Evaluation of the Anisotropic Radiative Conductivity of a Low-Density Carbon Fiber Material from Realistic Microscale Imaging

    Science.gov (United States)

    Nouri, Nima; Panerai, Francesco; Tagavi, Kaveh A.; Mansour, Nagi N.; Martin, Alexandre

    2015-01-01

    The radiative heat transfer inside a low-density carbon fiber insulator is analyzed using a three-dimensional direct simulation model. A robust procedure is presented for the numerical calculation of the geometric configuration factor to compute the radiative energy exchange processes among the small discretized surface areas of the fibrous material. The methodology is applied to a polygonal mesh of a fibrous insulator obtained from three-dimensional microscale imaging of the real material. The anisotropic values of the radiative conductivity are calculated for that geometry. The results yield both directional and thermal dependence of the radiative conductivity.

  19. Theoretical Electron Density Distributions for Fe- and Cu-Sulfide Earth Materials: A Connection between Bond Length, Bond Critical Point Properties, Local Energy Densities, and Bonded Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Gibbs, Gerald V.; Cox, David F.; Rosso, Kevin M.; Ross, Nancy L.; Downs, R. T.; Spackman, M. A.

    2007-03-01

    Bond critical point and local energy density properties together with net atomic charges were calculated for theoretical electron density distributions, F(r), generated for a variety of Fe and Cu metal-sulfide materials with high- and low-spin Fe atoms in octahedral coordination and high-spin Fe atoms in tetrahedral coordination. The electron density, F(rc), the Laplacian, 32F(rc), the local kinetic energy, G(rc), and the oxidation state of Fe increase as the local potential energy density, V(rc), the Fe-S bond lengths, and the coordination numbers of the Fe atoms decrease. The properties of the bonded interactions for the octahedrally coordinated low-spin Fe atoms for pyrite and marcasite are distinct from those for high-spin Fe atoms for troilite, smythite, and greigite. The Fe-S bond lengths are shorter and the values of F(rc) and 32F(rc) are larger for pyrite and marcasite, indicating that the accumulation and local concentration of F(r) in the internuclear region are greater than those involving the longer, high-spin Fe-S bonded interactions. The net atomic charges and the bonded radii calculated for the Fe and S atoms in pyrite and marcasite are also smaller than those for sulfides with high-spin octahedrally coordinated Fe atoms. Collectively, the Fe-S interactions are indicated to be intermediate in character with the low-spin Fe-S interactions having greater shared character than the highspin interactions. The bond lengths observed for chalcopyrite together with the calculated bond critical point properties are consistent with the formula Cu+Fe3+S2. The bond length is shorter and the F(rc) value is larger for the FeS4 tetrahedron displayed by metastable greigite than those displayed by chalcopyrite and cubanite, consistent with a proposal that the Fe atom in greigite is tetravalent. S-S bond paths exist between each of the surface S atoms of adjacent slabs of FeS6 octahedra comprising the layer sulfide smythite, suggesting that the neutral Fe3S4 slabs are

  20. Real-space density functional theory on graphical processing units: computational approach and comparison to Gaussian basis set methods

    CERN Document Server

    Andrade, Xavier

    2013-01-01

    We discuss the application of graphical processing units (GPUs) to accelerate real-space density functional theory (DFT) calculations. To make our implementation efficient, we have developed a scheme to expose the data parallelism available in the DFT approach; this is applied to the different procedures required for a real-space DFT calculation. We present results for current-generation GPUs from AMD and Nvidia, which show that our scheme, implemented in the free code OCTOPUS, can reach a sustained performance of up to 90 GFlops for a single GPU, representing an important speed-up when compared to the CPU version of the code. Moreover, for some systems our implementation can outperform a GPU Gaussian basis set code, showing that the real-space approach is a competitive alternative for DFT simulations on GPUs.

  1. Real-Space Density Functional Theory on Graphical Processing Units: Computational Approach and Comparison to Gaussian Basis Set Methods.

    Science.gov (United States)

    Andrade, Xavier; Aspuru-Guzik, Alán

    2013-10-01

    We discuss the application of graphical processing units (GPUs) to accelerate real-space density functional theory (DFT) calculations. To make our implementation efficient, we have developed a scheme to expose the data parallelism available in the DFT approach; this is applied to the different procedures required for a real-space DFT calculation. We present results for current-generation GPUs from AMD and Nvidia, which show that our scheme, implemented in the free code Octopus, can reach a sustained performance of up to 90 GFlops for a single GPU, representing a significant speed-up when compared to the CPU version of the code. Moreover, for some systems, our implementation can outperform a GPU Gaussian basis set code, showing that the real-space approach is a competitive alternative for DFT simulations on GPUs.

  2. Tilted Magnetic Levitation Enables Measurement of the Complete Range of Densities of Materials with Low Magnetic Permeability.

    Science.gov (United States)

    Nemiroski, Alex; Soh, Siowling; Kwok, Sen Wai; Yu, Hai-Dong; Whitesides, George M

    2016-02-03

    Magnetic levitation (MagLev) of diamagnetic or weakly paramagnetic materials suspended in a paramagnetic solution in a magnetic field gradient provides a simple method to measure the density of small samples of solids or liquids. One major limitation of this method, thus far, has been an inability to measure or manipulate materials outside of a narrow range of densities (0.8 g/cm(3) levitated magnetically. Tilting the MagLev device relative to the gravitational vector enables the magnetic force to be decreased (relative to the magnetic force) along the axis of measurement. This approach enables many practical measurements over the entire range of densities observed in matter at ambient conditions-from air bubbles (ρ ≈ 0) to osmium and iridium (ρ ≈ 23 g/cm(3)). The ability to levitate, simultaneously, objects with a broad range of different densities provides an operationally simple method that may find application to forensic science (e.g., for identifying the composition of miscellaneous objects or powders), industrial manufacturing (e.g., for quality control of parts), or resource-limited settings (e.g., for identifying and separating small particles of metals and alloys).

  3. Nanostructured Electrode Materials Derived from Metal-Organic Framework Xerogels for High-Energy-Density Asymmetric Supercapacitor.

    Science.gov (United States)

    Mahmood, Asif; Zou, Ruqiang; Wang, Qingfei; Xia, Wei; Tabassum, Hassina; Qiu, Bin; Zhao, Ruo

    2016-01-27

    This work successfully demonstrates metal-organic framework (MOF) derived strategy to prepare nanoporous carbon (NPC) with or without Fe3O4/Fe nanoparticles by the optimization of calcination temperature as highly active electrode materials for asymmetric supercapacitors (ASC). The nanostructured Fe3O4/Fe/C hybrid shows high specific capacitance of 600 F/g at a current density of 1 A/g and excellent capacitance retention up to 500 F/g at 8 A/g. Furthermore, hierarchically NPC with high surface area also obtained from MOF gels displays excellent electrochemical performance of 272 F/g at 2 mV/s. Considering practical applications, aqueous ASC (aASC) was also assembled, which shows high energy density of 17.496 Wh/kg at the power density of 388.8 W/kg. The high energy density and excellent capacity retention of the developed materials show great promise for the practical utilization of these energy storage devices.

  4. High-performance nickel-cobalt-boron material for an asymmetric supercapacitor with an ultrahigh energy density

    Science.gov (United States)

    Chen, Rongna; Liu, Lei; Zhou, Junshuang; Hou, Li; Gao, Faming

    2017-02-01

    Nickel-cobalt-borons are synthesized using a facile and cost-effective reduction method. The effects of Ni/Co molar ratios and crystallinity on its supercapacitive performance are systematically investigated. It was found that nickel-cobalt-borons with the Ni/Co ratio being 2:1 and amorphous structure manifest the optimum specific capacitance of 2226.96 F/g at a current density of 1 A/g and still remain 1879.2 F/g with a high discharge current density of 20 A/g. An asymmetric supercapacitor device (ASC) has been fabricated with nickel-cobalt-borons (Ni-Co-B) as the positive electrode and commercial activated carbon (CAC) as the negative electrode material. The Ni-Co-B//CAC delivers an ultrahigh energy density of 66.40 Wh/kg at a power density of 788.91 W/kg. This ASC remains 85.76% of its initial capacitance even after 5000 charge-discharge cycles. The results demonstrate that amorphous nickel-cobalt-boron material is a promising candidate for energy storage application.

  5. Conductive Polymer Binder for High-Tap-Density Nanosilicon Material for Lithium-Ion Battery Negative Electrode Application.

    Science.gov (United States)

    Zhao, Hui; Wei, Yang; Qiao, Ruimin; Zhu, Chenhui; Zheng, Ziyan; Ling, Min; Jia, Zhe; Bai, Ying; Fu, Yanbao; Lei, Jinglei; Song, Xiangyun; Battaglia, Vincent S; Yang, Wanli; Messersmith, Phillip B; Liu, Gao

    2015-12-09

    High-tap-density silicon nanomaterials are highly desirable as anodes for lithium ion batteries, due to their small surface area and minimum first-cycle loss. However, this material poses formidable challenges to polymeric binder design. Binders adhere on to the small surface area to sustain the drastic volume changes during cycling; also the low porosities and small pore size resulting from this material are detrimental to lithium ion transport. This study introduces a new binder, poly(1-pyrenemethyl methacrylate-co-methacrylic acid) (PPyMAA), for a high-tap-density nanosilicon electrode cycled in a stable manner with a first cycle efficiency of 82%-a value that is further improved to 87% when combined with graphite material. Incorporating the MAA acid functionalities does not change the lowest unoccupied molecular orbital (LUMO) features or lower the adhesion performance of the PPy homopolymer. Our single-molecule force microscopy measurement of PPyMAA reveals similar adhesion strength between polymer binder and anode surface when compared with conventional polymer such as homopolyacrylic acid (PAA), while being electronically conductive. The combined conductivity and adhesion afforded by the MAA and pyrene copolymer results in good cycling performance for the high-tap-density Si electrode.

  6. Tube-Super Dielectric Materials: Electrostatic Capacitors with Energy Density Greater than 200 J·cm−3

    Directory of Open Access Journals (Sweden)

    Francisco Javier Quintero Cortes

    2015-09-01

    Full Text Available The construction and performance of a second generation of super dielectric material based electrostatic capacitors (EC, with energy density greater than 200 J·cm−3, which rival the best reported energy density of electric double layer capacitors (EDLC, also known as supercapacitors, are reported. The first generation super dielectric materials (SDM are multi-material mixtures with dielectric constants greater than 1.0 × 105, composed of a porous, electrically insulating powder filled with a polarizable, ion-containing liquid. Second-generation SDMs (TSDM, introduced here, are anodic titania nanotube arrays filled with concentrated aqueous salt solutions. Capacitors using TiO2 based TSDM were found to have dielectric constants at ~0 Hz greater than 107 in all cases, a maximum operating voltage of greater than 2 volts and remarkable energy density that surpasses the highest previously reported for EC capacitors by approximately one order of magnitude. A simple model based on the classic ponderable media model was shown to be largely consistent with data from nine EC type capacitors employing TSDM.

  7. Temperature Buffer Test. Measurements of water content and density of the excavated buffer material

    Energy Technology Data Exchange (ETDEWEB)

    Johannesson, Lars-Erik [Clay Technology AB, Lund (Sweden)

    2010-12-15

    TBT (Temperature Buffer Test) is a joint project between SKB/ANDRA and supported by ENRESA (modeling) and DBE (instrumentation), which aims at understanding and modeling the thermo-hydromechanical behavior of buffers made of swelling clay submitted to high temperatures (over 100 deg C) during the water saturation process. The test was carried out at the - 420 m level in Aespoe HRL in a 8 meters deep and 1.76 m diameter deposition hole, with two heaters (3 m long, 0.6 m diameter), surrounded by a MX-80 bentonite buffer and a confining plug on top anchored with 9 rods. It was installed during spring 2003. The bentonite around upper heater was removed during the period October - December 2009 and the buffer around the lower heater was removed during January - Mars 2010. During dismantling of the buffer, samples were taken on which analyses were made. This report describes the work with the deteroemoeination of the water content and the density of the taken samples. Most of the samples were taken from the buffer by core drilling from the upper surface of each installed bentonite block. The cores had a diameter of about 50 mm and a maximum length equal to the original height of the bentonite blocks (about 500 mm). The water content of the buffer was determined by drying a sample at a temperature of 105 deg C for 24 h and the bulk density was determined by weighing a sample both in the air and immerged in paraffin oil with known density. The water content, dry density, degree of saturation and void ratio of the buffer were then plotted. The plots show that all parts of the buffer had taken up water and the degree of saturation of the buffer varied between 90 - 100%. Large variation in the dry density of the buffer was also observed.

  8. Quantitative evaluation of metal artifacts using different CBCT devices, high-density materials and field of views.

    Science.gov (United States)

    Codari, Marina; de Faria Vasconcelos, Karla; Ferreira Pinheiro Nicolielo, Laura; Haiter Neto, Francisco; Jacobs, Reinhilde

    2017-04-22

    To objectively compare the influence of different cone-beam computed tomography (CBCT) devices, high-density materials and field of views (FOVs) on metal artifact expression. For this in vitro study, three customized acrylic resin phantoms containing high-density materials cylinders: titanium, copper-aluminum alloy and amalgam were scanned on three CBCT devices using high-resolution protocols, same voxel size (0.2 mm) and different FOVs. After fully automatic segmentation and image registration, the same region of interest was defined for the small and medium FOVs. The difference between the segmented and the real volume of the metal cylinders was assessed. Moreover for each segmented slice, the area difference between the segmented and the real axial section was determined. The artifacts on the background were measured as normalizing standard deviation of voxel values in the vicinity of the cylinder, in three different distances. Considerable differences were observed in volume measurements for all CBCTs devices and materials for both FOV sizes (up to 67%). The slice per slice area analysis indicated higher artifacts at the edges of the metal cylinder. Within the materials, amalgam and titanium had, respectively, the worst and best artifact expression in all the CBCT devices. Standard deviation values varied differently between the three distances in each device. Our in vitro study showed that different CBCT devices, high-density materials and FOV should be considered while evaluating CBCT images. More carefully, diagnosis conclusions should be drawn in images containing amalgam and copper-aluminum alloy. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Density functional theory study of phase stability and defect thermodynamics in iron-oxyhydroxide mineral materials

    Science.gov (United States)

    Pinney, Nathan Douglas

    Due to their high surface area and reactivity toward a variety of heavy metal and oxyanion species of environmental concern, Fe-(oxyhydr)oxide materials play an important role in the geochemical fate of natural and anthropogenic contaminants in soils, aquifers and surface water environments worldwide. In this research, ab initio simulations describe the bulk structure, magnetic properties, and relative phase stability of major Fe-(oxyhydr)oxide materials, including hematite, goethite, lepidocrocite, and ferrihydrite.These bulk models are employed in further studies of point defect and alloy/dopant thermodynamics in these materials, allowing construction of a phase stability model that better replicates the structure and composition of real materials. Li + adsorption at the predominant goethite (101) surface is simulated using ab initio methods, offering energetic and structural insight into the binding mechanisms of metal cations over a range of surface protonation conditions.

  10. The primary circuit materials properties results analysis performed on archive material used in NPP V-1 and Kola NPP Units 1 and 2

    Energy Technology Data Exchange (ETDEWEB)

    Kupca, L.; Beno, P. [Nuclear Power Plants Research Institute Inc., Trnava (Slovakia)

    1997-04-01

    A very brief summary is provided of a primary circuit piping material properties analysis. The analysis was performed for the Bohunice V-1 reactor and the Kola-1 and -2 reactors. Assessment was performed on Bohunice V-1 archive materials and primary piping material cut from the Kola units after 100,000 hours of operation. Main research program tasks included analysis of mechanical properties, corrosion stability, and microstructural properties. Analysis results are not provided.

  11. Didactical Design Material Units of Distance and Speed to Developed Mathematical Connection in Elementary School

    Science.gov (United States)

    Jannah, R. R.; Apriliya, S.; Karlimah

    2017-03-01

    This study aims to develop alternative instructional design based of barriers learning which identified by developing mathematical connection capabilities to the material unit of distance and speed. The research was conducted in the fifth grade elementary school Instructional design is complemented with a hypothetical learning trajectory in the form of a pedagogical didactic anticipation. The method used is descriptive method with qualitative approach. Techniques data collection used were observation, interviews, and documentation. The instrument used the researchers themselves are equipped with an instrument written test. The data were analyzed qualitatively to determine the student learning obstacles, then arrange hypothetical learning trajectory and pedagogical didactic anticipation. Learning obstacle are identified, it is learning obstacle related the connections between mathematical topics, learning obstacle related with other disciplines, and learning obstacle related with everyday life. The results of this research are improvement and development of didactic design in mathematics which has activities mathematical connection to the material unit of distance and speed in elementary school. The learning activities are carried out is using varied methods include method lectures, demonstrations, practice and exercise, as well as using the modified instructional media.

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

    Science.gov (United States)

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

    2017-01-01

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

  13. Time-domain pumping a quantum-critical charge density wave ordered material

    Science.gov (United States)

    Matveev, O. P.; Shvaika, A. M.; Devereaux, T. P.; Freericks, J. K.

    2016-09-01

    We determine the exact time-resolved photoemission spectroscopy for a nesting driven charge density wave (described by the spinless Falicov-Kimball model within dynamical mean-field theory). The pump-probe experiment involves two light pulses: the first is an ultrashort intense pump pulse that excites the system into nonequilibrium, and the second is a lower amplitude, higher frequency probe pulse that photoexcites electrons. We examine three different cases: the strongly correlated metal, the quantum-critical charge density wave, and the critical Mott insulator. Our results show that the quantum critical charge density wave has an ultraefficient relaxation channel that allows electrons to be de-excited during the pump pulse, resulting in little net excitation. In contrast, the metal and the Mott insulator show excitations that are closer to what one expects from these systems. In addition, the pump field produces spectral band narrowing, peak sharpening, and a spectral gap reduction, all of which rapidly return to their field free values after the pump is over.

  14. Analysis of surface degradation of high density polyethylene (HDPE) insulation material due to tracking

    Indian Academy of Sciences (India)

    R Sarathi; S Chandrasekar; V Sabari Giri; C Venkataseshaiah; R Velmurugan

    2004-06-01

    In the present work, tracking phenomena has been studied with HDPE material under a.c. voltage, with ammonium chloride as the contaminant. It is noticed that the tracking time depends on the conductivity and flow rate of the contaminant. The diffusion coefficient of the material was obtained. The thermal and chemical stability of the material were identified by carrying out a methodical experimental study. The physico-chemical analyses viz. wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA), were carried out and it was concluded that the mechanism of tracking process is due to the surface degradation. The surface condition of the insulation structure was characterized for any surface discharges or tracking, using the leakage current measurement, utilizing the wavelet concepts.

  15. Distributed material density and anisotropy for optimized eigenfrequency of 2D continua

    DEFF Research Database (Denmark)

    Pedersen, Pauli; Pedersen, Niels Leergaard

    2015-01-01

    A practical approach to optimize a continuum/structural eigenfrequency is presented, including design of the distribution of material anisotropy. This is often termed free material optimization (FMO). An important aspect is the separation of the overall material distribution from the local design...... constitutive matrix. For 3D problems from 21 to 6 parameters, for 2D from 6 to 3 parameters, and for axisymmetric problems from 10 to 4 parameters....... are described by non-dimensional matrices with unity norms of trace and Frobenius, and thus this part of the optimized design has no influence on the mass distribution. Gradients of eigenfrequency with respect to the components of these non-dimensional constitutive matrices are therefore simplified...

  16. Density of loose-fill insulation material exposed to cyclic humidity conditions

    DEFF Research Database (Denmark)

    Rasmussen, Torben Valdbjørn

    This report presents a proposal for a standardised method for creep tests and the necessary theoretical and empirical framework that can be used to describe creep of granulated loose-fill material exposed to climate. Furthermore results from a round-robin test are shown. The round-robin test...... and Transport in Espoo and the Danish Building Research Institute department of Building Design and Technology. For the round-robin test a cellulosic fibre insulation material was used. The proposed standardised method for creep tests and theoretical and empirical framework are limited to cases when...

  17. Investigation of mud density and weighting materials effect on drilling fluid filter cake properties and formation damage

    Science.gov (United States)

    Fattah, K. A.; Lashin, A.

    2016-05-01

    Drilling fluid density/type is an important factor in drilling and production operations. Most of encountered problems during rotary drilling are related to drilling mud types and weights. This paper aims to investigate the effect of mud weight on filter cake properties and formation damage through two experimental approaches. In the first approach, seven water-based drilling fluid samples with same composition are prepared with different densities (9.0-12.0 lb/gal) and examined to select the optimum mud weight that has less damage. The second approach deals with investigating the possible effect of the different weighting materials (BaSO4 and CaCO3) on filter cake properties. High pressure/high temperature loss tests and Scanning Electron Microscopy (SEM) analyses were carried out on the filter cake (two selected samples). Data analysis has revealed that mud weigh of 9.5 lb/gal has the less reduction in permeability of ceramic disk, among the seven used mud densities. Above 10.5 ppg the effect of the mud weight density on formation damage is stabilized at constant value. Fluids of CaCO3-based weighting material, has less reduction in the porosity (9.14%) and permeability (25%) of the filter disk properties than the BaSO4-based fluid. The produced filter cake porosity increases (from 0.735 to 0.859) with decreasing of fluid density in case of drilling samples of different densities. The filtration loss tests indicated that CaCO3 filter cake porosity (0.52) is less than that of the BaSO4 weighted material (0.814). The thickness of the filter cake of the BaSO4-based fluid is large and can cause some problems. The SEM analysis shows that some major elements do occur on the tested samples (Ca, Al, Si, and Ba), with dominance of Ca on the expense of Ba for the CaCO3 fluid sample and vice versa. The less effect of 9.5 lb/gal mud sample is reflected in the well-produced inter-particle pore structure and relatively crystal size. A general recommendation is given to

  18. Changing patterns in the use, recycling, and material substitution of mercury in the United States

    Science.gov (United States)

    Wilburn, David R.

    2013-01-01

    Environmental concerns have led to numerous regulations that have dramatically decreased the reported production and use of mercury in the United States since the 1980s. Government legislation and subsequent industry actions have led to increased collection of mercury-containing materials and the recovery of mercury through recycling. Mercury emissions have been reduced and effective alternatives to mercury products have been developed for many applications. This study updates and quantifies the changes in demand, supply, use, and material flow for mercury in various sectors in the United States that have taken place since 1996. Nearly all primary mercury produced in the United States is derived as a byproduct of processing of gold and silver ore in Nevada. Since 2001, annual production of mercury from gold and silver mining in Nevada has decreased by 22 percent overall because ore from greater depths containing low grade mercury is recovered, and mercury emissions from this source have decreased by 95 percent as a result of increased regulation and improved collection and suppression technology. The distribution of consumption of mercury in the United States has changed as a result of regulation (elimination of large-scale mercury use in the paint and battery sectors), reduction by consumers (decommissioning of mercury-cell chloralkali manufacturing capacity), and technological advances (improvements in dental, lighting, and wiring sectors). Mercury use in the chloralkali sector, the leading end-use sector in the United States in 1996, has declined by 98 percent from 136 metric tons (t) in 1996 to about 0.3 t in 2010 because of increased processing and recycling efficiencies and plant closures or conversion to other technologies. As plants were closed, mercury recovered from the infrastructure of decommissioned plants has been exported, making the United States a net exporter of mercury, even though no mercury has been produced as the primary product from mines in

  19. Density Functional Theory Simulations Predict New Materials for Magnesium-Ion Batteries (Fact Sheet), NREL Highlights, Science

    Energy Technology Data Exchange (ETDEWEB)

    2011-10-01

    Multivalence is identified in the light element, B, through structure morphology. Boron sheets exhibit highly versatile valence, and the layered boron materials may hold the promise of a high-energy-density magnesium-ion battery. Practically, boron is superior to previously known multivalence materials, especially transition metal compounds, which are heavy, expensive, and often not benign. Based on density functional theory simulations, researchers at the National Renewable Energy Laboratory (NREL) have predicted a series of stable magnesium borides, MgB{sub x}, with a broad range of stoichiometries, 2 < x < 16, by removing magnesium atoms from MgB{sub 2}. The layered boron structures are preserved through an in-plane topological transformation between the hexagonal lattice domains and the triangular domains. The process can be reversibly switched as the charge transfer changes with Mg insertion/extraction. The mechanism of such a charge-driven transformation originates from the versatile valence state of boron in its planar form. The discovery of these new physical phenomena suggests the design of a high-capacity magnesium-boron battery with theoretical energy density 876 mAh/g and 1550 Wh/L.

  20. High-Throughput Characterization of Porous Materials Using Graphics Processing Units

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jihan; Martin, Richard L.; Rübel, Oliver; Haranczyk, Maciej; Smit, Berend

    2012-05-08

    We have developed a high-throughput graphics processing units (GPU) code that can characterize a large database of crystalline porous materials. In our algorithm, the GPU is utilized to accelerate energy grid calculations where the grid values represent interactions (i.e., Lennard-Jones + Coulomb potentials) between gas molecules (i.e., CH$_{4}$ and CO$_{2}$) and material's framework atoms. Using a parallel flood fill CPU algorithm, inaccessible regions inside the framework structures are identified and blocked based on their energy profiles. Finally, we compute the Henry coefficients and heats of adsorption through statistical Widom insertion Monte Carlo moves in the domain restricted to the accessible space. The code offers significant speedup over a single core CPU code and allows us to characterize a set of porous materials at least an order of magnitude larger than ones considered in earlier studies. For structures selected from such a prescreening algorithm, full adsorption isotherms can be calculated by conducting multiple grand canonical Monte Carlo simulations concurrently within the GPU.

  1. High-Energy-Density LCA-Coupled Structural Energetic Materials for Counter WMD Applications

    Science.gov (United States)

    2014-04-01

    morphology , etc.) of reactants. In the case of the equivolumetric Ta+Fe2O3 powder mixtures, pre-densification results in generating Fe2O3 as the more...published in the following papers. • N.N. Thadhani and J.K. Cochran, "Energetic Materials", DTRA Basic and Applied Research Program Newsletter , V2, N3, p

  2. The influence of increasing riverbank vegetation density on bed shear stresses and transport of bed material

    Science.gov (United States)

    Liu, Da; Valyrakis, Manousos

    2017-04-01

    Riverbank vegetation can significantly influence the hydrodynamics of the river, such as flow velocity and bed shear stress, as well as affecting geomorphic processes across it. The aim of this study is to report preliminary results from extensive set of experiments aiming to better establish the link between flow and solid transport processes at the vicinity of the riverbank. A set of laboratory experiments is conducted in a recirculating flume with a series of acrylic panels mounted on the side of the flume at an angle to simulate the riverbank, and a large number of acrylic rods placed on top of it simulating riparian vegetation. Ten different vegetation configurations are examined, for the range of vegetation densities found in natural river systems. Three of these are configured in linear arrangement; another three of them in staggered; and the other four follow a random configuration at chosen densities. Turbulent flow is measured across the channel using acoustic Doppler velocimetry (ADV) along a dense measurement grid. The measurements covered the whole cross-section of the channel at the main measurement plane, as well as the riverbank region. The results reported include mean streamwise flow velocity and turbulent intensity profiles, bed shear stresses, momentum transfer at the riverbank region. These are associated with transport metrics obtained using an instrumented tracer particle entrained from different release locations (both from the centerline of the main channel and the near bank region). The results show that the flow velocity at the riverbank reduces with increasing densities of riparian vegetation, while they increase at the main channel. Likewise, the bed shear stresses increased at the main channel, and decreased within the vegetated riverbank, which is replicated by the observations from the particle transport experiments.

  3. High-density polyethylene pipe: A new material for pass-by passive integrated transponder antennas

    Science.gov (United States)

    Kazyak, David C.; Zydlewski, Joseph

    2012-01-01

    Pass-by passive integrated transponder (PIT) antennas are widely used to study the movements of fish in streams. At many sites, stream conditions make it difficult to maintain antennas and obtain a continuous record of movement. We constructed pass-by PIT antennas by using high-density polyethylene (HDPE) and found them to be robust to high flows and winter ice flows. Costs for HDPE antennas were similar to those of traditional polyvinyl chloride (PVC) antennas, although construction was somewhat more complicated. At sites where PVC antennas are frequently damaged, HDPE is a durable and economical alternative for PIT antenna construction.

  4. Free-space reflection method for measuring moisture content and bulk density of particulate materials at microwave frequency

    Science.gov (United States)

    Li, Chenxiao; Han, Bing; Zhang, Tao

    2015-03-01

    A measurement system based on free-space reflection method is designed for simultaneous and independent determination of moisture content and bulk density of particulate materials. The proposed system consists of microwave cavity oscillator, horn antenna, slide rail, sample holder, mixer, and digital meter. Sand and rice with different moisture contents and bulk densities are chosen as samples. Calibration models for moisture content and bulk density are proposed according to the measurement of the position of the minimum of the traveling-standing wave and the ratio of the maximum-to-minimum field strength of the traveling-standing wave at different temperatures. The moisture constant, ranging from 0% to 24.6%, is obtained with a coefficient of determination (R2) greater than 0.982 and a standard error of prediction (SEP) value of less than 0.695%. The bulk density, ranging from 0.501 g/cm3 to 1.822 g/cm3, is determined with a R2 ≥ 0.961 and a SEP value ranging from 0.0144 g/cm3 to 0.0382 g/cm3 for different samples.

  5. Interface structure of Ag(111)/SnO2(200) composite material studied by density functional theory

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Electric contact material of Ag/SnO2 was successfully synthesized by in situ process method.The in-terface structure was characterized by high-resolution transmission electron microscopy(HTEM) and simulated at atomic scale on computer.The mean-square displacements of atoms near the interface were calculated,and the results showed that near the interface both Ag side and SnO2 were mis-matched and this effect decays rapidly far from the interface.By inspecting the calculated density of states(DOS),we found that the electric-conductivity of this composite material was decreased because of the localized 4d and 2p electrons of Ag and O near the Fermi surface,respectively.Electron density changed acutely across the interface,so that there was no extra compound precipitated.A mi-cro-electric field also formed in the whole material due to the interface structure,and this may affect the electron conduction and the related electric-conductivity of the composite.It is found that the interface cohesive energy of Ag(111)/SnO2(200) was-3.50 J/m2,which is higher than the experimental results.

  6. A tunneling current density model for ultra thin HfO2 high-k dielectric material based MOS devices

    Science.gov (United States)

    Maity, Niladri Pratap; Maity, Reshmi; Thapa, R. K.; Baishya, Srimanta

    2016-07-01

    In this paper, an analytical model for evaluation of tunneling current density of ultra thin MOS devices is presented. The impacts of the promising high-k dielectric material, HfO2 on the current density model have been carried out. In this work, improvement in the results is brought in by taking into account the barrier height lowering due to the image force effect. The considered voltage range is from 0 to ψ1/e i.e., 0 neglecting the image force effect for a MOS device consisting asymmetric barrier. Later, image force effect of ultra thin oxide layer has been introduced for practical potential barrier by superimposing the potential barrier on the trapezoidal barrier. Theoretical predictions are compared with the results obtained by the 2-D numerical device simulator ATLAS and published experimental results. Excellent agreements among the three are observed.

  7. High-T{sub c} superconductor/linear low density polyethylene (LLDPE) composite materials for diamagnetic applications

    Energy Technology Data Exchange (ETDEWEB)

    Bhadrakumari, S [Department of Physics, St. Berchman' s College, Changanassery, Kerala (India); Predeep, P [Condensed Matter Physics Laboratory, Department of Physics, Sree Narayana College, Kollam 691 001, Kerala (India)

    2006-08-15

    A series of composite samples of YBa{sub 2}Cu{sub 3}O{sub 7-x} and linear low density polyethylene (Y-123/LLDPE) with volume percentage ranging from 0 to 75% was prepared. The crystallinity of the composites was studied using x-ray diffraction (XRD) patterns. It is found that the percentage of crystallinity in the composite samples increases with increasing volume of the LLDPE. A four-phase system for the composite materials may be inferred from a combination of XRD and density data. Repulsive force measurements showed that the diamagnetic properties were preserved in the composites and the samples exhibited appreciable magnetic levitation forces and this force increases with increasing volume fraction of the superconductor filler.

  8. High-Pressure Preparation of High-Density Cu2ZnSnS4 Materials

    Science.gov (United States)

    Yi-Ming, Li; Li-Xia, Qiu; Zhan-Hui, Ding; Yong-Feng, Li; Bin, Yao; Zhen-Yu, Xiao; Pin-Wen, Zhu

    2016-07-01

    Not Available Supported by the National Natural Science Foundation of China under Grant Nos 10874178, 11074093, 61205038 and 11274135, the National Found for Fostering Talents of Basic Science under Grant No J1103202, the Ph.D. Programs Foundation of Ministry of Education of China under Grant No 20120061120011, the Open Project of State Key Laboratory of Superhard Materials of Jilin University, and the State Key Laboratory of Inorganic Synthesis and Preparative Chemistry of Jilin University.

  9. Combining density functional theory calculations, supercomputing, and data-driven methods to design new materials (Conference Presentation)

    Science.gov (United States)

    Jain, Anubhav

    2017-04-01

    Density functional theory (DFT) simulations solve for the electronic structure of materials starting from the Schrödinger equation. Many case studies have now demonstrated that researchers can often use DFT to design new compounds in the computer (e.g., for batteries, catalysts, and hydrogen storage) before synthesis and characterization in the lab. In this talk, I will focus on how DFT calculations can be executed on large supercomputing resources in order to generate very large data sets on new materials for functional applications. First, I will briefly describe the Materials Project, an effort at LBNL that has virtually characterized over 60,000 materials using DFT and has shared the results with over 17,000 registered users. Next, I will talk about how such data can help discover new materials, describing how preliminary computational screening led to the identification and confirmation of a new family of bulk AMX2 thermoelectric compounds with measured zT reaching 0.8. I will outline future plans for how such data-driven methods can be used to better understand the factors that control thermoelectric behavior, e.g., for the rational design of electronic band structures, in ways that are different from conventional approaches.

  10. Scalable real space pseudopotential-density functional codes for materials applications

    Science.gov (United States)

    Chelikowsky, James R.; Lena, Charles; Schofield, Grady; Saad, Yousef; Deslippe, Jack; Yang, Chao

    2015-03-01

    Real-space pseudopotential density functional theory has proven to be an efficient method for computing the properties of matter in many different states and geometries, including liquids, wires, slabs and clusters with and without spin polarization. Fully self-consistent solutions have been routinely obtained for systems with thousands of atoms. However, there are still systems where quantum mechanical accuracy is desired, but scalability proves to be a hindrance, such as large biological molecules or complex interfaces. We will present an overview of our work on new algorithms, which offer improved scalability by implementing another layer of parallelism, and by optimizing communication and memory management. Support provided by the SciDAC program, Department of Energy, Office of Science, Advanced Scientific Computing Research and Basic Energy Sciences. Grant Numbers DE-SC0008877 (Austin) and DE-FG02-12ER4 (Berkeley).

  11. Relativistic plasma optics enabled by near-critical density nanostructured material

    CERN Document Server

    Bin, J H; Wang, H Y; Streeter, M J V; Kreuzer, C; Kiefer, D; Yeung, M; Cousens, S; Foster, P S; Dromey, B; Yan, X Q; Meyer-ter-Vehn, J; Zepf, M; Schreiber, J

    2014-01-01

    The nonlinear optical properties of a plasma due to the relativistic electron motion in an intense laser field are of fundamental importance for current research and the generation of brilliant laser-driven sources of particles and photons1-15. Yet, one of the most interesting regimes, where the frequency of the laser becomes resonant with the plasma, has remained experimentally hard to access. We overcome this limitation by utilizing ultrathin carbon nanotube foam16 (CNF) targets allowing the strong relativistic nonlinearities at near- critical density (NCD) to be exploited for the first time. We report on the experimental realization of relativistic plasma optics to spatio-temporally compress the laser pulse within a few micrometers of propagation, while maintaining about half its energy. We also apply the enhanced laser pulses to substantially improve the properties of an ion bunch accelerated from a secondary target. Our results provide first insights into the rich physics of NCD plasmas and the opportuni...

  12. Crystal structure of the high-energy-density material guanylurea dipicrylamide

    Directory of Open Access Journals (Sweden)

    Raik Deblitz

    2014-08-01

    Full Text Available The title compound, 1-carbamoylguanidinium bis(2,4,6-trinitrophenylamide [H2NC(=ONHC(NH22]+[N{C6H2(NO23-2,4,6}2]− (= guanylurea dipicrylamide, was prepared as dark-red block-like crystals in 70% yield by salt-metathesis reaction between guanylurea sulfate and sodium dipicrylamide. In the solid state, the new compound builds up an array of mutually linked guanylurea cations and dipicrylamide anions. The crystal packing is dominated by an extensive network of N—H...O hydrogen bonds, resulting in a high density of 1.795 Mg m−3, which makes the title compound a potential secondary explosive.

  13. Crystal structure of the high-energy-density material guanylurea dipicryl-amide.

    Science.gov (United States)

    Deblitz, Raik; Hrib, Cristian G; Hilfert, Liane; Edelmann, Frank T

    2014-08-01

    The title compound, 1-carbamoylguanidinium bis-(2,4,6-tri-nitro-phen-yl)amide [H2NC(=O)NHC(NH2)2](+)[N{C6H2(NO2)3-2,4,6}2](-) (= guanylurea dipicryl-amide), was prepared as dark-red block-like crystals in 70% yield by salt-metathesis reaction between guanylurea sulfate and sodium dipicryl-amide. In the solid state, the new compound builds up an array of mutually linked guanylurea cations and dipicryl-amide anions. The crystal packing is dominated by an extensive network of N-H⋯O hydrogen bonds, resulting in a high density of 1.795 Mg m(-3), which makes the title compound a potential secondary explosive.

  14. High Torque Density Transverse Flux Machine without the Need to Use SMC Material for 3D Flux Paths

    DEFF Research Database (Denmark)

    Lu, Kaiyuan; Wu, Weimin

    2015-01-01

    This paper presents a new transverse flux permanent magnet machine. In a normal transverse flux machine, complicated 3-D flux paths often exist. Such 3-D flux paths would require the use of soft magnetic composites material instead of laminations for construction of the machine stator. In the new...... machine topology proposed in this paper, by advantageously utilizing the magnetic flux path provided by an additional rotor, use of laminations that allow 2-D flux paths only will be sufficient to accomplish the required 3-D flux paths. The machine also has a high torque density and is therefore...

  15. Density Functional Theory Meta-GGA+U Study of Water Incorporation in the Metal Organic Framework Material Cu-BTC

    OpenAIRE

    Cockayne, Eric; Nelson, Eric B.

    2015-01-01

    Water absorption in the metal-organic framework (MOF) material Cu-BTC, up to a concentration of 3.5 H$_2$O per Cu ion, is studied via density functional theory at the meta-GGA+U level. The stable arrangements of water molecules show chains of hydrogen-bonded water molecules and a tendency to form closed cages at high concentration. Water clusters are stabilized primarily by a combination of water-water hydrogen bonding and Cu-water oxygen interactions. Stability is further enhanced by van der...

  16. Field assessment of the urban density of air conditioning use in the United Kingdom in non domestic buildings

    Energy Technology Data Exchange (ETDEWEB)

    Caeiro, Jorge A.J. [The Bartlett School of Graduate Studies, Univ. College London (United Kingdom); Brown, Neil [Inst. of Energy and Sustainable Development, De Montfort Univ., Leicester (United Kingdom); Altan, Hasim [School of Architecture, Building Energy Analysis Unit, The Univ. of Sheffield (United Kingdom)

    2007-07-01

    Increasing sales of air conditioning (AC) will exacerbate future heat waves, paradoxically with positive feedback, since the resulting augmented emission of greenhouse effect gases will in turn contribute to global warming. According to a research study carried out in 2000 (Hitchin, E.R et al), the total air-conditioned UK building area, under both cooling and reverse systems, was estimated to have almost doubled over the previous decade and is projected to nearly double again by 2020. This has now become an urgent concern. However the estimated increase is based on sales data and the detailed patterns of increase in urban density of air conditioning use in service and retail sectors in the UK are largely unknown. Energy use information was collected from a major study carried out in the early 1990s. Since then there have been many changes in these sectors, with shifts in location patterns, and increased use of air conditioning in offices and shops. Unfortunately, AC unit sales figures may not indicate which stock is new, and which is sold as replacement. In this paper, the results of surveys of over 2000 retail premises and offices are presented. These are derived from ongoing surveys with the goal of a statistically representative picture of AC usage within the UK.

  17. Muscle-tendon units localization and activation level analysis based on high-density surface EMG array and NMF algorithm

    Science.gov (United States)

    Huang, Chengjun; Chen, Xiang; Cao, Shuai; Zhang, Xu

    2016-12-01

    Objective. Some skeletal muscles can be subdivided into smaller segments called muscle-tendon units (MTUs). The purpose of this paper is to propose a framework to locate the active region of the corresponding MTUs within a single skeletal muscle and to analyze the activation level varieties of different MTUs during a dynamic motion task. Approach. Biceps brachii and gastrocnemius were selected as targeted muscles and three dynamic motion tasks were designed and studied. Eight healthy male subjects participated in the data collection experiments, and 128-channel surface electromyographic (sEMG) signals were collected with a high-density sEMG electrode grid (a grid consists of 8 rows and 16 columns). Then the sEMG envelopes matrix was factorized into a matrix of weighting vectors and a matrix of time-varying coefficients by nonnegative matrix factorization algorithm. Main results. The experimental results demonstrated that the weightings vectors, which represent invariant pattern of muscle activity across all channels, could be used to estimate the location of MTUs and the time-varying coefficients could be used to depict the variation of MTUs activation level during dynamic motion task. Significance. The proposed method provides one way to analyze in-depth the functional state of MTUs during dynamic tasks and thus can be employed on multiple noteworthy sEMG-based applications such as muscle force estimation, muscle fatigue research and the control of myoelectric prostheses. This work was supported by the National Nature Science Foundation of China under Grant 61431017 and 61271138.

  18. Comparative studies on physico-mechanical properties of composite materials of low density polyethylene and raw/calcined kaolin

    Directory of Open Access Journals (Sweden)

    Amit Mallik

    2015-06-01

    Full Text Available The paper describes the preparation of the composite materials of low density polyethylene (LDPE as the base mixed separately with raw kaolin and the same calcined at 800 °C under the same variation in weight percentage using single-screw extruder and a mixing machine operated at a temperature between 190 and 200 °C. Some of the mechanical and physical properties such as Young's modulus, elongation at break, shore hardness and water absorption were determined at different weight fractions of filler (0, 2, 7, 10 and 15%. It was found that the addition of filler increases the mechanical properties. Absorption test was done in water at different immersion times for different composites. The degree of water absorption of composite materials was found to decrease with increasing wt% of kaolin filler (0–15% according to Fick's law. Calcined kaolin produces better mechanical properties than raw kaolin.

  19. A chemistry and material perspective on lithium redox flow batteries towards high-density electrical energy storage.

    Science.gov (United States)

    Zhao, Yu; Ding, Yu; Li, Yutao; Peng, Lele; Byon, Hye Ryung; Goodenough, John B; Yu, Guihua

    2015-11-21

    Electrical energy storage system such as secondary batteries is the principle power source for portable electronics, electric vehicles and stationary energy storage. As an emerging battery technology, Li-redox flow batteries inherit the advantageous features of modular design of conventional redox flow batteries and high voltage and energy efficiency of Li-ion batteries, showing great promise as efficient electrical energy storage system in transportation, commercial, and residential applications. The chemistry of lithium redox flow batteries with aqueous or non-aqueous electrolyte enables widened electrochemical potential window thus may provide much greater energy density and efficiency than conventional redox flow batteries based on proton chemistry. This Review summarizes the design rationale, fundamentals and characterization of Li-redox flow batteries from a chemistry and material perspective, with particular emphasis on the new chemistries and materials. The latest advances and associated challenges/opportunities are comprehensively discussed.

  20. Theoretical Study of the N-NO2 Bond Dissociation Energies for Energetic Materials with Density Functional Theory

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-Hong; TANG Zheng-Xin; Abraham F.Jalbout; ZHANG Xian-Zhou; CHENG Xin-Lu

    2008-01-01

    The N-NO2 bond dissociation energies (BDEs) for 7 energetic materials were computed by means of accurate density functional theory (B3LYP, B3PW91 and B3P86) with 6-31G** and 6-311G** basis sets. By comparing the computed energies and experimental results, we find that the B3P86/6-311G** method can give good results of BDE, which has the mean absolute deviation of 1.30 kcal/mol. In addition, substituent effects were also taken into account. It is noted that the Hammett constants of substituent groups are related to the BDEs of the N-NO2 bond and the bond dissociation energies of the energetic materials studied decrease when increasing the number of NO2 group.

  1. Covalent Organic Framework Material bearing Phloroglucinol Building Units as a Potent Anticancer Agent

    KAUST Repository

    Bhanja, Piyali

    2017-08-23

    Covalent organic frameworks (COFs) having periodicity in pores of nanoscale dimensions can be suitably designed for the organic building units bearing reactive functional groups at their surfaces. Thus, they are an attractive option as an anticancer agent to overcome the limitations of chemotherapy. Herein, we first report a new porous biodegradable nitrogen containing COF material, EDTFP-1 (ethylenedianiline-triformyl phloroglucinol), synthesized using 4,4\\'-ethylenedianiline and 2,4,6-triformylphloroglucinol via Schiff base condensation reaction. EDTFP-1 exhibited 3D-hexagonal porous structure with average pores of ca. 1.5 nm dimension. Here, we have explored the anti-cancer potentiality of EDTFP-1. Result demonstrated an enhanced cytotoxicity was observed against four cancer cells HCT 116, HepG2, A549, and MIA-Paca2 with significant lower IC50 on HCT116 cells. Additionally, EDTFP-1-induced cell death was associated with the characteristic apoptotic changes like cell membrane blebbing, nuclear DNA fragmentation, externalization of phosphatidylserine from the cell membrane followed by a loss of mitochondrial membrane potential as well as modulation of pro and anti-apoptotic proteins. Further, the result depicted a direct correlation between the generations of ROS with mitochondrial-dependant apoptosis through the involvement of p53 phosphorylation upon EDTFP-1 induction, suggesting this COF material is a novel chemotherapeutic agent for cancer treatment.

  2. Scalable real space pseudopotential density functional codes for materials in the exascale regime

    Science.gov (United States)

    Lena, Charles; Chelikowsky, James; Schofield, Grady; Biller, Ariel; Kronik, Leeor; Saad, Yousef; Deslippe, Jack

    Real-space pseudopotential density functional theory has proven to be an efficient method for computing the properties of matter in many different states and geometries, including liquids, wires, slabs, and clusters with and without spin polarization. Fully self-consistent solutions using this approach have been routinely obtained for systems with thousands of atoms. Yet, there are many systems of notable larger sizes where quantum mechanical accuracy is desired, but scalability proves to be a hindrance. Such systems include large biological molecules, complex nanostructures, or mismatched interfaces. We will present an overview of our new massively parallel algorithms, which offer improved scalability in preparation for exascale supercomputing. We will illustrate these algorithms by considering the electronic structure of a Si nanocrystal exceeding 104 atoms. Support provided by the SciDAC program, Department of Energy, Office of Science, Advanced Scientific Computing Research and Basic Energy Sciences. Grant Numbers DE-SC0008877 (Austin) and DE-FG02-12ER4 (Berkeley).

  3. Molecular Design and Property Prediction for a Series of Novel Dicyclic Cyclotrimethylene Trinitramines (RDX) Derivatized as High Energy Density Materials.

    Science.gov (United States)

    Shen, Cheng; Wang, Pengcheng; Lu, Ming

    2015-07-23

    Quantum chemistry calculations and thermodynamics methods were carried out to screen out novel high energy density materials (HEDMs) from several new derivatives with dicyclic structures of Cyclotrimethylene trinitramine (RDX). Their volumes, densities, heats of formation, detonation properties and impact sensitivities have been calculated with thermodynamics methods under DFT B3LYP 6-31++g (d, p) level and all of these compounds exhibit good performance as HEDMs. Especially, R4 has given outstanding values as a potential HEDM. Its crystal density (2.07 g/cm(3)), heat of detonation (1.67 kJ/g), detonation velocity (10051m/s), and detonation pressure (48.5 GPa) are even higher than those of CL-20 while its impact sensitivity (h50, 16 cm) remains a relative safety value. The results indicate that the derivative work in common explosives is a good strategy which can design novel HEDMs with high energetic properties and low sensitivity. And furthermore, some mature processes can be used to synthesize them.

  4. Device Architecture and Materials for Organic Light-Emitting Devices Targeting High Current Densities and Control of the Triplet Concentration

    CERN Document Server

    Schols, Sarah

    2011-01-01

    Device Architecture and Materials for Organic Light-Emitting Devices focuses on the design of new device and material concepts for organic light-emitting devices, thereby targeting high current densities and an improved control of the triplet concentration. A new light-emitting device architecture, the OLED with field-effect electron transport, is demonstrated. This device is a hybrid between a diode and a field-effect transistor. Compared to conventional OLEDs, the metallic cathode is displaced by one to several micrometers from the light-emitting zone, reducing optical absorption losses. The electrons injected by the cathode accumulate at an organic heterojunction and are transported to the light-emission zone by field-effect. High mobilities for charge carriers are achieved in this way, enabling a high current density and a reduced number of charge carriers in the device. Pulsed excitation experiments show that pulses down to 1 µs can be applied to this structure without affecting the light intensity, sug...

  5. An Evaluation of United States Government Immigration Education Materials [and] Investigation of United States Immigration Education Correspondence Courses.

    Science.gov (United States)

    Nielson, Lynn E.

    An analysis of eight current government publications on citizenship for immigrants to the United States and results of a survey investigating immigration education correspondence courses are provided. In the first part, subjective evaluations of eight textbooks, based on seven designated criteria (copyright, readability, subject matter,…

  6. Tomography of atomic number and density of materials using dual-energy imaging and the Alvarez and Macovski attenuation model

    Science.gov (United States)

    Paziresh, M.; Kingston, A. M.; Latham, S. J.; Fullagar, W. K.; Myers, G. M.

    2016-06-01

    Dual-energy computed tomography and the Alvarez and Macovski [Phys. Med. Biol. 21, 733 (1976)] transmitted intensity (AMTI) model were used in this study to estimate the maps of density (ρ) and atomic number (Z) of mineralogical samples. In this method, the attenuation coefficients are represented [Alvarez and Macovski, Phys. Med. Biol. 21, 733 (1976)] in the form of the two most important interactions of X-rays with atoms that is, photoelectric absorption (PE) and Compton scattering (CS). This enables material discrimination as PE and CS are, respectively, dependent on the atomic number (Z) and density (ρ) of materials [Alvarez and Macovski, Phys. Med. Biol. 21, 733 (1976)]. Dual-energy imaging is able to identify sample materials even if the materials have similar attenuation coefficients at single-energy spectrum. We use the full model rather than applying one of several applied simplified forms [Alvarez and Macovski, Phys. Med. Biol. 21, 733 (1976); Siddiqui et al., SPE Annual Technical Conference and Exhibition (Society of Petroleum Engineers, 2004); Derzhi, U.S. patent application 13/527,660 (2012); Heismann et al., J. Appl. Phys. 94, 2073-2079 (2003); Park and Kim, J. Korean Phys. Soc. 59, 2709 (2011); Abudurexiti et al., Radiol. Phys. Technol. 3, 127-135 (2010); and Kaewkhao et al., J. Quant. Spectrosc. Radiat. Transfer 109, 1260-1265 (2008)]. This paper describes the tomographic reconstruction of ρ and Z maps of mineralogical samples using the AMTI model. The full model requires precise knowledge of the X-ray energy spectra and calibration of PE and CS constants and exponents of atomic number and energy that were estimated based on fits to simulations and calibration measurements. The estimated ρ and Z images of the samples used in this paper yield average relative errors of 2.62% and 1.19% and maximum relative errors of 2.64% and 7.85%, respectively. Furthermore, we demonstrate that the method accounts for the beam hardening effect in density (ρ) and

  7. Ecohydrologic controls on vegetation density and evapotranspiration partitioning across the climatic gradients of the central United States

    Directory of Open Access Journals (Sweden)

    J. P. Kochendorfer

    2008-03-01

    Full Text Available The soil-water balance and plant water use are investigated over a domain encompassing the central United States using the Statistical-Dynamical Ecohydrology Model (SDEM. The seasonality in the model and its use of the two-component Shuttleworth-Wallace canopy model allow for application of an ecological optimality hypothesis in which vegetation density, in the form of peak green leaf area index (LAI, is maximized, within upper and lower bounds, such that, in a typical season, soil moisture in the latter half of the growing season just reaches the point at which water stress is experienced. Another key feature of the SDEM is that it partitions evapotranspiration into transpiration, evaporation from canopy interception, and evaporation from the soil surface. That partitioning is significant for the soil-water balance because the dynamics of the three processes are very different. The partitioning and the model-determined peak in green LAI are validated based on observations in the literature, as well as through the calculation of water-use efficiencies with modeled transpiration and large-scale estimates of grassland productivity. Modeled-determined LAI are seen to be at least as accurate as the unaltered satellite-based observations on which they are based. Surprising little dependence on climate and vegetation type is found for the percentage of total evapotranspiration that is soil evaporation, with most of the variation across the study region attributable to soil texture and the resultant differences in vegetation density. While empirical evidence suggests that soil evaporation in the forested regions of the most humid part of the study region is somewhat overestimated, model results are in excellent agreement with observations from croplands and grasslands. The implication of model results for water-limited vegetation is that the higher (lower soil moisture content in wetter (drier climates is more-or-less completely offset by the greater

  8. Structural materialization of stainless steel molds and dies by the low temperature high density plasma nitriding

    Directory of Open Access Journals (Sweden)

    Aizawa Tatsuhiko

    2015-01-01

    Full Text Available Various kinds of stainless steels have been widely utilized as a mold substrate material for injection molding and as a die for mold-stamping and direct stamping processes. Since they suffered from high temperature transients and thermal cycles in practice, they must be surface-treated by dry and wet coatings, or, by plasma nitriding. Martensitic stainless steel mold was first wet plated by the nickel phosphate (NiP, which was unstable at the high temperature stamping condition; and, was easy to crystalize or to fracture by itself. This issue of nuisance significantly lowered the productivity in fabrication of optical elements at present. In the present paper, the stainless steel mold was surface-treated by the low-temperature plasma nitriding. The nitrided layer by this surface modification had higher nitrogen solute content than 4 mass%; the maximum solid-solubility of nitrogen is usually 0.1 mass% in the equilibrium phase diagram. Owing to this solid-solution with high nitrogen concentration, the nitrided layer had high hardness of 1400 Hv within its thickness of 40 μm without any formation of nitrides after 14.4 ks plasma nitriding at 693 K. This nitrogen solid-solution treated stainless steel had thermal resistivity even at the mold-stamping conditions up to 900 K.

  9. The recent prevalence of Osteoporosis and low bone mass in the United States based on bone mineral density at the Femoral Neck or Lumbar Spine

    Science.gov (United States)

    The goal of our study was to estimate the prevalence of osteoporosis and low bone mass based on bone mineral density (BMD) at the femoral neck and the lumbar spine in adults 50 years and older in the United States (US). We applied prevalence estimates of osteoporosis or low bone mass at the femoral ...

  10. Furazans with Azo Linkages: Stable CHNO Energetic Materials with High Densities, Highly Energetic Performance, and Low Impact and Friction Sensitivities.

    Science.gov (United States)

    Qu, Yanyang; Zeng, Qun; Wang, Jun; Ma, Qing; Li, Hongzhen; Li, Haibo; Yang, Guangcheng

    2016-08-22

    Various highly energetic azofurazan derivatives were synthesized by simple and efficient chemical routes. These nitrogen-rich materials were fully characterized by FTIR spectroscopy, elemental analysis, multinuclear NMR spectroscopy, and high-resolution mass spectrometry. Four of them were further confirmed structurally by single-crystal X-ray diffraction. These compounds exhibit high densities, ranging from 1.62 g cm(-3) up to a remarkably high 2.12 g cm(-3) for nitramine-substituted azofurazan DDAzF (2), which is the highest yet reported for an azofurazan-based CHNO energetic compound and is a consequence of the formation of strong intermolecular hydrogen-bonding networks. From the heats of formation, calculated with Gaussian 09, and the experimentally determined densities, the energetic performances (detonation pressure and velocities) of the materials were ascertained with EXPLO5 v6.02. The results suggest that azofurazan derivatives exhibit excellent detonation properties (detonation pressures of 21.8-46.1 GPa and detonation velocities of 6602-10 114 m s(-1) ) and relatively low impact and friction sensitivities (6.0-80 J and 80-360 N, respectively). In particular, they have low electrostatic spark sensitivities (0.13-1.05 J). These properties, together with their high nitrogen contents, make them potential candidates as mechanically insensitive energetic materials with high-explosive performance. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. The 5th surveillance testing for Kori unit 2 reactor vessel materials

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Kee Ok; Kim, Byoung Chul; Lee, Sam Lai; Choi, Kwon Jae; Gong, Un Sik; Chang, Jong Hwa; Joo, Yong Sun; Ahn, Sang Bok; Hong, Joon Hwa [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2001-03-01

    Surveillance testing for reactor vessel materials is performed in order to evaluate the irradiation embrittlement due to neutrons during operation and set the condition of safe operation of nuclear reactor. The 5th surveillance testing was performed completely by Korea Atomic Energy Research Institute at Taejeon after the capsule was transported from Kori site including its removal from reactor. Fast neutron fluences for capsules were calculated and various testing including mechanical and chemistry analysis were performed in order to evaluate the integrity of Kori unit 2 reactor vessel during the operation until life time. The evaluation results are as follows; Fast neutron fluences for capsules V, R, P, T and N are 2.837E+18, 1.105E+19, 2.110E+19, 3.705E+19 and 4.831E+19n/cm{sup 2}, respectively. The bias factor, the ratio of measurement/calculation, was 0.918 for the 1st through 5th testing and the calculational uncertainty, 11.6% satisfied the requirement of USNRC Reg.Guide DG-1053, 20%. The best estimated neutron fluence for reactor vessel inside surface was 1.898E+19n/cm{sup 2} based on the end of 15th fuel cycle and it was predicted that the fluences of vessel inside surface at 32, 40, 48 and 56EFPY would reach 4.203E+19, 5.232E+19, 6.262E+19 and 7.291E+19n/cm{sup 2} based on the current calculation. The result through this analysis for Kori unit 2 showed that there would be no problem for the pressurized thermal shock(PTS) during the operation until design life. 49 refs., 35 figs., 48 tabs. (Author)

  12. The 4th surveillance testing for Kori unit 3 reactor vessel materials

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Kee Ok; Kim, Byoung Chul; Lee, Sam Lai; Choi, Kwun Jae; Gong, Un Sik; Chang, Jong Hwa; Joo, Yong Sun; Ahn, Sang Bok; Hong, Joon Hwa [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2000-10-01

    Surveillance testing for reactor vessel materials is performed in order to evaluate the irradiation embrittlement due to neutrons during operation and set the condition of safe operation of nuclear reactor. The 4th surveillance testing was performed completely by Korea Atomic Energy Research Institute at Taejeon after the capsule was transported from Kori site including its removal from reactor. Fast neutron fluences for capsules were calculated and various testing including mechanical and chemistry analysis were performed in order to evaluate the integrity of Kori unit 3 reactor vessel during the operation until life time. The evaluation results are as follows; Fast neutron fluences for capsules U, V, X and W are 4.983E+18, 1.641E+19, 3.158E+19, and 4.469E+19n/cm{sup 2}, respectively. The bias factor, the ratio of calculation/measurement, was 0.840 for the 1st through 4th testing and the calculational uncertainty, 12% satisfied the requirement of USNRC Reg.Guide DG-1053, 20%. The best estimated neutron fluence for reactor vessel inside surface was 1.362E+19n/cm{sup 2} based on the end of 12th fuel cycle and it was predicted that the fluences of vessel inside surface at 32, 40, 48 and 56EFPY would reach 3.481E+19, 4.209E+19, 5.144E+19 and 5.974E+19n/cm{sup 2} based on the current calculation. The result through this analysis for Kori unit 3 showed that there would be no problem for the pressurized thermal shock(PTS) during the operation until design life. 48 refs., 35 figs., 41 tabs. (Author)

  13. Report on residual radioactive materials on public or acquired lands of the United States

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-07-01

    This report identifies sites located on public or acquired lands of the United States containing residual radioactive materials and other radioactive waste (excluding waste resulting from the production of electric energy) and was developed in accordance with the provisions of Section 114(b) of Public Law 95-604, "Uranium Mill Tailings Radiation Control Act of 1978," enacted on November 8, 1978. Additionally, the report specifies which Federal agency has jurisdiction over such sites and, where appropriate data were available, provides a description of the radiological status of each of the sites reported. For purpose of providing a timely report t o t h e Congress, a termination date of May 31, 1979 was established for the receipt, correlation, and analysis of the input data. As of this date, residual radioactive materials and other radioactive waste have been identified by six Federal agencies at 48 sites throughout the United States. Table 1 on page vi provides a summary listing of the number of sites under the jurisdiction of each of these reporting agencies. A cross listing in tabular form by affected state is presented in Table 2 on page viii. Of the 48 sites reported, 36 are located i n three western states - Colorado (27 sites), Wyoming (5 sites), and Utah (4 sites). Based upon t h e data submitted, the sites were categorized into three broad radiological status categories -- controlled, unstabilized, and risk to the public. At controlled sites, the residue is stabilized, access t o t h e site is controlled, the s i t e is well monitored, and does not currently constitute a risk to the public. At sites in the unstabilized category, a probability exists for the spread of contamination. Sites in the risk category contain residue which represents a long-term risk to the public under present conditions. Of the 48 reported sites,. 9 (approximately 19%) could be classified in the controlled category; 38 (approximately 79%) were in the unstabilized category and

  14. Nano-sized structured layered positive electrode materials to enable high energy density and high rate capability lithium batteries

    Science.gov (United States)

    Deng, Haixia; Belharouak, Ilias; Amine, Khalil

    2012-10-02

    Nano-sized structured dense and spherical layered positive active materials provide high energy density and high rate capability electrodes in lithium-ion batteries. Such materials are spherical second particles made from agglomerated primary particles that are Li.sub.1+.alpha.(Ni.sub.xCo.sub.yMn.sub.z).sub.1-tM.sub.tO.sub.2-dR.sub.d- , where M is selected from can be Al, Mg, Fe, Cu, Zn, Cr, Ag, Ca, Na, K, In, Ga, Ge, V, Mo, Nb, Si, Ti, Zr, or a mixture of any two or more thereof, R is selected from F, Cl, Br, I, H, S, N, or a mixture of any two or more thereof, and 0.ltoreq..alpha..ltoreq.0.50; 0materials and their use in electrochemical devices are also described.

  15. The 5th surveillance testing for Kori unit 1 reactor vessel materials

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Kee Ok; Kim, Byoung Chul; Lee, Sam Lai; Choi, Kwun Jae; Gong, Un Sik; Chang, Jong Hwa; Joo, Yong Sun; Ahn, Sang Bok; Hong, Joon Hwa [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2000-08-01

    Surveillance testing for reactor vessel materials is performed in order to evaluate the irradiation embrittlement due to neutrons during operation and set the condition of safe operation of nuclear reactor. The 5th surveillance testing was performed primarily by Korea Atomic Energy Research Institute and Westinhouse corporation partially involved in testing and calculation data evaluation in order to obtain reliable test result. Fast neutron fluences for capsule V, T, S, R and P were 5.087E+18, 1.115E+19, 1.228E+19, 2.988E+19, and 3.938E+19n/cm2, respectively. The bias factor, the ratio of calculation/measurement, was 0.940 for the 1st through 5th testing and the calculational uncertainty, 7% satisfied the requirement of USNRC Reg.Guide DG-1053, 20%. The best estimated neutron fluence for reactor vessel inside surface was 1.9846E+19n/cm{sup 2} based on the end of 17th fuel cycle and it was predicted that the fluences of vessel inside surface at 24, 32, 40 and 48EFPY would reach 3.0593E+19, 4.0695E+19, 5.0797E+19 and 6.0900E+19n/cm{sup 2} based on the current calculation. PTS analysis for Kori unit 1 showed that 27.93EFPY was the threshold value for 300 deg F requirement. 71 refs., 33 figs., 52 tabs. (Author)

  16. Influence of composite restorative materials and light-curing units on diametrical tensile strength.

    Science.gov (United States)

    Tolosa, Maria Cecília Caldas Giorgi; Paulillo, Luís Alexandre Maffei Sartini; Giannini, Marcelo; Santos, Alex José Souza dos; Dias, Carlos Tadeu dos Santos

    2005-01-01

    The aim of this study was to evaluate the diametrical tensile strength (DTS) of three light-curing photo-activated composites with two different light curing units (LCU). Three types of dental restorative composites were used in this study: micro filled A110 (3M Espe); P60 (3M Espe) for posterior restorations, and micro-hybrid Charisma (Heraeus-Kulzer). The two LCUs were: halogen light (HAL) (Degulux, Degussa) and blue light emitting diode (LED) (Ultrablue, DMC). Resin composite specimens were inserted incrementally into a Teflon split mold measuring 3 mm in depth and 6 mm in internal diameter, and cured using either LCU (n = 10). Specimens were placed into a dark bottle containing distilled water at 37 degrees C for 7 days. DTS tests were performed in a Universal Testing Machine (0.5 mm/min). Data were submitted to two-way ANOVA and Tukey's test. Results were (MPa): A110/HAL: 276.50 +/- 62.94a; A110/LED: 306.01 +/- 65.16a; P60/HAL: 568.29 +/- 60.77b and P60/LED: 543.01 +/- 83.65b; Charisma/HAL: 430.94 +/- 67.28c; Charisma/LED: 435.52 +/- 105.12c. Results suggested that no significant difference in DTS was obtained with LCUs for the same composite. However, resin composite restorative materials presented different DTS.

  17. Considering adaptation of electrical ovens with unit-type releasing to peculiarities of thermal energization of mineral raw materials

    Science.gov (United States)

    Zvezdin, A. V.; Bryanskikh, T. B.

    2017-01-01

    The paper gives a short overview of technologies of mineral raw material thermal treatment where application of electrical ovens with unit-type releasing is possible. Efficiency of such ovens for vermiculite concentrate and conglomerate roasting is proved by more than 13-years experience of their industrial operation. The paper furthermore considers alternative connections of energotechnological blocks of an oven in order to determine its efficient design for specific technology related to one or another mineral raw material.

  18. Fabrication and materials properties of high-density polyethylene (HDPE)/biphasic calcium phosphate (BCP) hybrid bone plates

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Sun Young; Youn, Min Ho; Lim, Youn Mook; Gwon, Hui Jeong; Park, Jong Seok; Nho, Young Chang [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2010-06-15

    Biphasic calcium phosphate-reinforced high-density polyethylene (BCP/HDPE) hybrid composite is a new orthopedic biomaterial, which was made to simulate a natural bone composition. Calcium phosphate systems and HDPE hybrid composites have been used in biomedical applications without any inflammatory response. Differences in natural bone of both materials have motivated the use of coupling agents to improve their interfacial interfacial interactions. The composites were prepared using medical grade BCP powder and granular polyethylene. This material was produced by replacing the mineral component and collagen soft tissue of the bone with BCP and HDPE, respectively. As expected, increased volume fraction of either reinforcement type over 0 {approx} 50 vol.% resulted in a increased Vickers hardness and Young's modulus. Thus, BCP particle-reinforced HDPE composites possessed improved material and mechanical properties. BCP particles-reinforced composites were anisotropic due to an alignment of the particles in the matrix during a processing. On the other hand, bending and tensile strength was dramatically changed in the matrix. To change the material and mechanical properties of HDPE/BCP composites, the process of a blending was used, and its effect on the microstructure and mechanical proprieties of HDPE/BCP composites were investigated by means of FT-IR/ATR spectroscopy, XRD, FE-SEM, Vickers Hardness Testing Machine, Universal Testing Machine, Mercury Porosimeter and Ultrasonic Flaw Detector at room temperature. For the evaluation of the cell viability and proliferation onto the external surface of HDPE/BCP hybrid plates with a HaCaT cell line, which is a multipotent cell line able to differentiate towards different phenotypes under the action of biological factors, has been evaluated with in vitro studies and quantified by colormetric assays. These findings indicate that the HDPE/BCP hybrid plates are biocompatible and non-toxic.

  19. Correlation between Cohesive Energy Density, Fractional Free Volume, and Gas Transport Properties of Poly(ethylene-co-vinyl acetate Materials

    Directory of Open Access Journals (Sweden)

    Piotr Kubica

    2015-01-01

    Full Text Available The transport properties of the poly(ethylene-co-vinyl acetate (EVA materials to He, N2, O2, and CO2 are correlated with two polymer molecular structure parameters, that is, cohesive energy density (CED and fractional free volume (FFV, determined by the group contribution method. In our preceding paper, the attempt was made to approximate EVA permeability using a linear function of 1/FFV as predicted by the free volume theory. However, the deviations from this relationship appeared to be significant. In this paper, it is shown that permeation of gas molecules is controlled not only by free volume but also by the polymer cohesive energy. Moreover, the behavior of CO2 was found to differ significantly from that of other gases. In this instance, the correlation is much better when diffusivity instead of permeability is taken into account in a modified transport model.

  20. Investigation of nano-talc as a filling material and a reinforcing agent in high density polyethylene (HDPE)

    Institute of Scientific and Technical Information of China (English)

    CHEN Nanchun; MA Lei; ZHANG Tao

    2006-01-01

    An experiment of producing high density polyethylene (HDPE) nano-composite filled with 4wt.% talc was presented. Acting as filler and a reinforcing agent in the HDPE, talc powder, sized at around 5 μm, was surface-treated with aluminum diethylene glycol dinitrate coupling agent before adding to the HDPE. Analyses of the reinforced HDPE nano-composite show significant improvement in its mechanical properties including, tensile strength (>26 MPa), break elongation (<1.1%), flexural strength (>22 MPa), and friction coefficients<0.11. The results demonstrate that, after surface-treated, talc can be used as a promising filling material and a reinforcing agent in making HDPE nano-composite.

  1. Relationship between anode material, supporting electrolyte and current density during electrochemical degradation of organic compounds in water.

    Science.gov (United States)

    Guzmán-Duque, Fernando L; Palma-Goyes, Ricardo E; González, Ignacio; Peñuela, Gustavo; Torres-Palma, Ricardo A

    2014-08-15

    Taking crystal violet (CV) dye as pollutant model, the electrode, electrolyte and current density (i) relationship for electro-degrading organic molecules is discussed. Boron-doped diamond (BDD) or Iridium dioxide (IrO2) used as anode materials were tested with Na2SO4 or NaCl as electrolytes. CV degradation and generated oxidants showed that degradation pathways and efficiency are strongly linked to the current density-electrode-electrolyte interaction. With BDD, the degradation pathway depends on i: If idegraded by OH radicals, whereas if i>i(lim), generated oxidants play a major role in the CV elimination. When IrO2 was used, CV removal was not dependent on i, but on the electrolyte. Pollutant degradation in Na2SO4 on IrO2 seems to occur via IrO3; however, in the presence of NaCl, degradation was dependent on the chlorinated oxidative species generated. In terms of efficiency, the Na2SO4 electrolyte showed better results than NaCl when BDD anodes were employed. On the contrary, NaCl was superior when combined with IrO2. Thus, the IrO2/Cl(-) and BDD/SO4(2-) systems were better at removing the pollutant, being the former the most effective. On the other hand, pollutant degradation with the BDD/SO4(2-) and IrO2/Cl(-) systems is favored at low and high current densities, respectively. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Phantom-less bone mineral density (BMD) measurement using dual energy computed tomography-based 3-material decomposition

    Science.gov (United States)

    Hofmann, Philipp; Sedlmair, Martin; Krauss, Bernhard; Wichmann, Julian L.; Bauer, Ralf W.; Flohr, Thomas G.; Mahnken, Andreas H.

    2016-03-01

    Osteoporosis is a degenerative bone disease usually diagnosed at the manifestation of fragility fractures, which severely endanger the health of especially the elderly. To ensure timely therapeutic countermeasures, noninvasive and widely applicable diagnostic methods are required. Currently the primary quantifiable indicator for bone stability, bone mineral density (BMD), is obtained either by DEXA (Dual-energy X-ray absorptiometry) or qCT (quantitative CT). Both have respective advantages and disadvantages, with DEXA being considered as gold standard. For timely diagnosis of osteoporosis, another CT-based method is presented. A Dual Energy CT reconstruction workflow is being developed to evaluate BMD by evaluating lumbar spine (L1-L4) DE-CT images. The workflow is ROI-based and automated for practical use. A dual energy 3-material decomposition algorithm is used to differentiate bone from soft tissue and fat attenuation. The algorithm uses material attenuation coefficients on different beam energy levels. The bone fraction of the three different tissues is used to calculate the amount of hydroxylapatite in the trabecular bone of the corpus vertebrae inside a predefined ROI. Calibrations have been performed to obtain volumetric bone mineral density (vBMD) without having to add a calibration phantom or to use special scan protocols or hardware. Accuracy and precision are dependent on image noise and comparable to qCT images. Clinical indications are in accordance with the DEXA gold standard. The decomposition-based workflow shows bone degradation effects normally not visible on standard CT images which would induce errors in normal qCT results.

  3. Spectroscopic Investigation of the Canopy Configurations in Nanoparticle Organic Hybrid Materials of Various Grafting Densities during CO 2 Capture

    KAUST Repository

    Petit, Camille

    2012-01-12

    Novel liquid-like nanoparticle organic hybrid materials (NOHMs) made of polyetheramine chains tethered onto functionalized silica nanoparticles were synthesized and characterized before and after exposure to CO 2 using NMR, Raman, and ATR FT-IR spectroscopies in order to investigate the effect of the grafting densities on the NOHM canopy structure. Considering the promising tunable properties for CO 2 capture of NOHMs, this study was conducted to provide important structural information to better design NOHMs for CO 2 capture. In order to minimize the CO 2 absorption via enthalpic effect and provide a more accurate assessment of the structural effects, the NOHMs were synthesized without task-specific groups. A greater chain ordering and decreased intermolecular interactions were observed in NOHMs compared to the unbound polymer. This was attributed to the specific structural arrangement of the frustrated canopy. The distinct configuration of grafted polymer chains caused different CO 2 packing and CO 2-induced swelling behaviors between the NOHMs and the unbound polymer. The grafting density influenced the ordering and coupling of the polymer chains and CO 2-induced swelling. Its effect on the CO 2 packing behavior was less pronounced. © 2011 American Chemical Society.

  4. Dentist material selection for single-unit crowns: Findings from the National Dental Practice-Based Research Network.

    Science.gov (United States)

    Makhija, Sonia K; Lawson, Nathaniel C; Gilbert, Gregg H; Litaker, Mark S; McClelland, Jocelyn A; Louis, David R; Gordan, Valeria V; Pihlstrom, Daniel J; Meyerowitz, Cyril; Mungia, Rahma; McCracken, Michael S

    2016-12-01

    Dentists enrolled in the National Dental Practice-Based Research Network completed a study questionnaire about techniques and materials used for single-unit crowns and an enrollment questionnaire about dentist/practice characteristics. The objectives were to quantify dentists' material recommendations and test the hypothesis that dentist's and practice's characteristics are significantly associated with these recommendations. Surveyed dentists responded to a contextual scenario asking what material they would use for a single-unit crown on an anterior and posterior tooth. Material choices included: full metal, porcelain-fused-to-metal (PFM), all-zirconia, layered zirconia, lithium disilicate, leucite-reinforced ceramic, or other. 1777 of 2132 eligible dentists responded (83%). The top 3 choices for anterior crowns were lithium disilicate (54%), layered zirconia (17%), and leucite-reinforced glass ceramic (13%). There were significant differences (p<0.05) by dentist's gender, race, years since graduation, practice type, region, practice busyness, hours worked/week, and location type. The top 3 choices for posterior crowns were all-zirconia (32%), PFM (31%), and lithium disilicate (21%). There were significant differences (p<0.05) by dentist's gender, practice type, region, practice busyness, insurance coverage, hours worked/week, and location type. Network dentists use a broad range of materials for single-unit crowns for anterior and posterior teeth, adopting newer materials into their practices as they become available. Material choices are significantly associated with dentist's and practice's characteristics. Decisions for crown material may be influenced by factors unrelated to tooth and patient variables. Dentists should be cognizant of this when developing an evidence-based approach to selecting crown material. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Material characterization and computer model simulation of low density polyurethane foam used in a rodent traumatic brain injury model.

    Science.gov (United States)

    Zhang, Liying; Gurao, Manish; Yang, King H; King, Albert I

    2011-05-15

    Computer models of the head can be used to simulate the events associated with traumatic brain injury (TBI) and quantify biomechanical response within the brain. Marmarou's impact acceleration rodent model is a widely used experimental model of TBI mirroring axonal pathology in humans. The mechanical properties of the low density polyurethane (PU) foam, an essential piece of energy management used in Marmarou's impact device, has not been fully characterized. The foam used in Marmarou's device was tested at seven strain rates ranging from quasi-static to dynamic (0.014-42.86 s⁻¹) to quantify the stress-strain relationships in compression. Recovery rate of the foam after cyclic compression was also determined through the periods of recovery up to three weeks. The experimentally determined stress-strain curves were incorporated into a material model in an explicit Finite Element (FE) solver to validate the strain rate dependency of the FE foam model. Compression test results have shown that the foam used in the rodent impact acceleration model is strain rate dependent. The foam has been found to be reusable for multiple impacts. However the stress resistance of used foam is reduced to 70% of the new foam. The FU_CHANG_FOAM material model in an FE solver has been found to be adequate to simulate this rate sensitive foam.

  6. Relationship between anode material, supporting electrolyte and current density during electrochemical degradation of organic compounds in water

    Energy Technology Data Exchange (ETDEWEB)

    Guzmán-Duque, Fernando L. [Grupo de diagnóstico y control de la contaminación, Facultad de ingeniería, Universidad de Antioquia, A.A. 1226, Medellín (Colombia); Palma-Goyes, Ricardo E. [Grupo de Investigación en Remediación Ambiental y Biocatálisis, Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquía Udea, A.A. 1226, Medellín (Colombia); González, Ignacio [Universidad Autónoma Metropolitana-Iztapalapa, Departamento de Química, Av. San Rafael Atlixco No 186, C.P 09340, México D.F (Mexico); Peñuela, Gustavo [Grupo de diagnóstico y control de la contaminación, Facultad de ingeniería, Universidad de Antioquia, A.A. 1226, Medellín (Colombia); Torres-Palma, Ricardo A., E-mail: rtorres@matematicas.udea.edu.co [Grupo de Investigación en Remediación Ambiental y Biocatálisis, Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquía Udea, A.A. 1226, Medellín (Colombia)

    2014-08-15

    Highlights: • Pathway and efficiency are linked to the current-electrode–electrolyte interaction. • Unlike BDD, IrO{sub 2} route was independent of current but dependent on the electrolyte. • IrO{sub 2}/SO{sub 4}{sup 2−} and IrO{sub 2}/Cl{sup −} routes were via IrO{sub 3} and chlorine species, respectively. • BDD/SO{sub 4}{sup 2−} and IrO{sub 2}/Cl{sup −} systems were favored at low and high currents, respectively. - Abstract: Taking crystal violet (CV) dye as pollutant model, the electrode, electrolyte and current density (i) relationship for electro-degrading organic molecules is discussed. Boron-doped diamond (BDD) or Iridium dioxide (IrO{sub 2}) used as anode materials were tested with Na{sub 2}SO{sub 4} or NaCl as electrolytes. CV degradation and generated oxidants showed that degradation pathways and efficiency are strongly linked to the current density-electrode–electrolyte interaction. With BDD, the degradation pathway depends on i: If i < the limiting current density (i{sub lim}), CV is mainly degraded by ·OH radicals, whereas if i > i{sub lim}, generated oxidants play a major role in the CV elimination. When IrO{sub 2} was used, CV removal was not dependent on i, but on the electrolyte. Pollutant degradation in Na{sub 2}SO{sub 4} on IrO{sub 2} seems to occur via IrO{sub 3}; however, in the presence of NaCl, degradation was dependent on the chlorinated oxidative species generated. In terms of efficiency, the Na{sub 2}SO{sub 4} electrolyte showed better results than NaCl when BDD anodes were employed. On the contrary, NaCl was superior when combined with IrO{sub 2}. Thus, the IrO{sub 2}/Cl{sup −} and BDD/SO{sub 4}{sup 2−} systems were better at removing the pollutant, being the former the most effective. On the other hand, pollutant degradation with the BDD/SO{sub 4}{sup 2−} and IrO{sub 2}/Cl{sup −} systems is favored at low and high current densities, respectively.

  7. Low Density Materials

    Science.gov (United States)

    2013-03-07

    Orthogonal transport of phonons for thermal management • Mechanical reinforcement MURI 11: Nanofabrication of 3D Nanotube Architectures 14...in Aerospace Platforms 27 Self-Similar Hierarchical Honeycombs A new class of self-similar ( fractal - appearing) hierarchical honeycombs with a...Optimum topology of hierarchical honeycombs, which approaches the fractal limit. DISTRIBUTION STATEMENT A – Unclassified, Unlimited Distribution 28

  8. Low Density Materials

    Science.gov (United States)

    2012-03-09

    achieve: - Organo -solubility - Structural rigidity and toughness - High thermal stability 6 DISTRIBUTION A: Approved for public release; distribution...unlimited. 1D Carbon Nanotubes 2D Graphene Nanostructured Carbon 0D Fullerene 3D ? 19 DISTRIBUTION A: Approved for public release...distribution is unlimited. MURI 11 Topic: Nanofabrication of 3D Nanotube Architectures Objective: Controlled assembly and atomic-scale bonding of

  9. Naturally Occurring Radioactive Materials in Coals and Coal Combustion Residuals in the United States.

    Science.gov (United States)

    Lauer, Nancy E; Hower, James C; Hsu-Kim, Heileen; Taggart, Ross K; Vengosh, Avner

    2015-09-15

    The distribution and enrichment of naturally occurring radioactive materials (NORM) in coal combustion residuals (CCRs) from different coal source basins have not been fully characterized in the United States. Here we provide a systematic analysis of the occurrence of NORM ((232)Th, (228)Ra, (238)U, (226)Ra, and (210)Pb) in coals and associated CCRs from the Illinois, Appalachian, and Powder River Basins. Illinois CCRs had the highest total Ra ((228)Ra + (226)Ra = 297 ± 46 Bq/kg) and the lowest (228)Ra/(226)Ra activity ratio (0.31 ± 0.09), followed by Appalachian CCRs (283 ± 34 Bq/kg; 0.67 ± 0.09), and Powder River CCRs (213 ± 21 Bq/kg; 0.79 ± 0.10). Total Ra and (228)Ra/(226)Ra variations in CCRs correspond to the U and Th concentrations and ash contents of their feed coals, and we show that these relationships can be used to predict total NORM concentrations in CCRs. We observed differential NORM volatility during combustion that results in (210)Pb enrichment and (210)Pb/(226)Ra ratios greater than 1 in most fly-ash samples. Overall, total NORM activities in CCRs are 7-10- and 3-5-fold higher than NORM activities in parent coals and average U.S. soil, respectively. This study lays the groundwork for future research related to the environmental and human health implications of CCR disposal and accidental release to the environment in the context of this elevated radioactivity.

  10. Determining the effectiveness of illustrated communication material for communication with intubated patients at an intensive care unit.

    Science.gov (United States)

    Otuzoğlu, Münevver; Karahan, Azize

    2014-10-01

    Communication with non-speaking patients in intensive care unit is stress for both nurse and patients. Semi-experimental study that took place at a University Hospital was to develop illustrated material for patient communication and determine its effectiveness. The study sample consisted of 90 intubated patients at the Adult Cardiovascular Intensive Care Unit who had undergone open heart surgery. The patients were divided into the intervention and control groups. Data analysis was with descriptive statistics and the χ(2) test. The illustrated communication material was stated to be helpful by 77.8% and partially helpful by 22.2% of the intervention group patients regarding the communication between the health-care staff and the patients. Control group patients had more difficulties communicating with the health-care staff. Illustrated communication material was an effective method in communicating with intubated patients. © 2013 Wiley Publishing Asia Pty Ltd.

  11. Stockless Medical Materials Management: Applications for the United States Air Force Medical Service

    Science.gov (United States)

    1991-09-01

    percent would agree with the following stockless materials management definition . This research effort will adopt the following stockless materials... management definition : In a stockless program, the distributor takes over the hospitals central distribution function (i.e., the "pick-and-pack" operation...study developed a generally accepted stockless materials management definition . It defines stockless materials management as an inventory system where

  12. Far infrared conductivity of charge density wave materials and the oxygen isotope effect in high-T sub c superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Creager, W.N.

    1991-09-01

    The far infrared reflectance and conductivity of (Ta{sub 1-x}Nb{sub x}Se{sub 4}){sub 2}I and TaS{sub 3} have been measured to determine the origin of a huge infrared resonance that dominates the charge density wave (CDW) dynamics along with the pinned acoustic phason mode in the related materials (TaSe{sub 4}){sub 2}I and K{sub 0. 3}MoO{sub 3}. The measurements cover frequencies from 3 to 700cm{sup {minus}1} and the temperature range from 15K to 300K. In the niobium-doped alloys (Ta{sub 1-x}Nb{sub x}Se{sub 4}){sub 2}I, the size and frequency of the giant infrared mode remain nearly constant as the impurity concentration x is increased. For TaS{sub 3}, the pinned acoustic phason near 0.5cm{sup {minus}1} dominates {var epsilon}({omega}) and an additional small mode lies near 9cm{sup {minus}1}. The latter mode is much smaller than the infrared mode in other CDW materials. These results rule out several models of a generic infrared mode'' in CDW excitations. They are compared in detail to the predictions of a recent theory attributing the infrared mode to a bound collective mode localized at impurity sites within the crystal. The transmittance of K{sub 0.3}MoO{sub 3} has been measured at 1.2K with a strong dc electric field applied across the crystal. Under these conditions, the charge density wave depins abruptly and carries large currents with near-zero differential resistance. For some samples, the low-frequency transmittance is enhanced slightly when the CDW depins. The magnitude of the oxygen isotope effect in the high-{Tc} superconductor YBa{sub 2}Cu{sub 3}O{sub 7} has been determined by substitution of {sup 18}O for {sup 16}O. A series of cross-exchanges was performed on high-quality polycrystalline specimens to eliminate uncertainties due to sample heat treatments and sample inhomogeneities.

  13. The StreamCat Dataset: Accumulated Attributes for NHDPlusV2 Catchments (Version 2.1) for the Conterminous United States: 2010 US Census Road Density

    Science.gov (United States)

    This dataset represents the road density within individual, local NHDPlusV2 catchments and upstream, contributing watersheds. Attributes of the landscape layer were calculated for every local NHDPlusV2 catchment and accumulated to provide watershed-level metrics. (See Supplementary Info for Glossary of Terms) This data set is derived from TIGER/Line Files of roads in the conterminous United States. Road density describes how many kilometers of road exist in a square kilometer. A raster was produced using the ArcGIS Line Density Tool to form the landscape layer for analysis. (see Data Sources for links to NHDPlusV2 data and Census Data) The (kilometer of road/square kilometer) was summarized by local catchment and by watershed to produce local catchment-level and watershed-level metrics as a continuous data type (see Data Structure and Attribute Information for a description).

  14. Mechanical Properties of Ti-6Al-4V Octahedral Porous Material Unit Formed by Selective Laser Melting

    Directory of Open Access Journals (Sweden)

    Jianfeng Sun

    2012-01-01

    Full Text Available The Ti-6Al-4V octahedral porous material unit is designed to calculate its load. In this paper, ANSYS is adopted for the load simulation of the unit. And a simplified model of dimensional theoretical calculation is established, by which the analytical equation of the fracture load is obtained and the calculation of the load of Ti-6Al-4V is completed. Moreover, selective laser melting is adopted in processing the Ti-6Al-4V porous material unit. The experimental value of fracture load of this material is obtained through compression experiment. The results show that the simulation curves approximate the variation tendency of the elastic deformation of the compression curves; the curves of theoretical calculation approximate the general variation tendency; and the experimental value of fracture load is very close to the theoretical value. Therefore, the theoretical prediction accuracy of fracture load is high, which lays the foundation for the mechanical properties of the octahedral porous material.

  15. Closure Report for Corrective Action Unit 166: Storage Yards and Contaminated Materials, Nevada Test Site, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    NSTec Environmental Restoration

    2009-08-01

    Corrective Action Unit (CAU) 166 is identified in the Federal Facility Agreement and Consent Order (FFACO) as 'Storage Yards and Contaminated Materials' and consists of the following seven Corrective Action Sites (CASs), located in Areas 2, 3, 5, and 18 of the Nevada Test Site: CAS 02-42-01, Condo Release Storage Yd - North; CAS 02-42-02, Condo Release Storage Yd - South; CAS 02-99-10, D-38 Storage Area; CAS 03-42-01, Conditional Release Storage Yard; CAS 05-19-02, Contaminated Soil and Drum; CAS 18-01-01, Aboveground Storage Tank; and CAS 18-99-03, Wax Piles/Oil Stain. Closure activities were conducted from March to July 2009 according to the FF ACO (1996, as amended February 2008) and the Corrective Action Plan for CAU 166 (U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office, 2007b). The corrective action alternatives included No Further Action and Clean Closure. Closure activities are summarized. CAU 166, Storage Yards and Contaminated Materials, consists of seven CASs in Areas 2, 3, 5, and 18 of the NTS. The closure alternatives included No Further Action and Clean Closure. This CR provides a summary of completed closure activities, documentation of waste disposal, and confirmation that remediation goals were met. The following site closure activities were performed at CAU 166 as documented in this CR: (1) At CAS 02-99-10, D-38 Storage Area, approximately 40 gal of lead shot were removed and are currently pending treatment and disposal as MW, and approximately 50 small pieces of DU were removed and disposed as LLW. (2) At CAS 03-42-01, Conditional Release Storage Yard, approximately 7.5 yd{sup 3} of soil impacted with lead and Am-241 were removed and disposed as LLW. As a BMP, approximately 22 ft{sup 3} of asbestos tile were removed from a portable building and disposed as ALLW, approximately 55 gal of oil were drained from accumulators and are currently pending disposal as HW, the portable building was removed and

  16. Single and multiple scattering XAFS Debye-Waller factors for crystalline materials using periodic Density Functional Theory

    Energy Technology Data Exchange (ETDEWEB)

    Dimakis, N; Mion, T [Department of Physics and Geology, University of Texas-Pan American, Edinburg, TX 78539 (United States); Bunker, G, E-mail: dimakis@utpa.ed [Department of Biological Chemical and Physical Sciences, Illinois Institute of Technology, Chicago, IL 60616 (United States)

    2009-11-15

    We present an accurate and efficient technique for calculating thermal X-ray absorption fine structure (XAFS) Debye-Waller factors (DWFs) applicable to crystalline materials. Using Density Functional Theory on a 3x3x3 supercell pattern of MnO structure, under the nonlocal hybrid B3LYP functional paired with Gaussian local basis sets, we obtain the normal mode eigenfrequencies and eigenvectors; these parameters are in turn used to calculate single and multiple scattering XAFS DWFs. The DWFs obtained via this technique are temperature dependent expressions and can be used to substantially reduce the number of fitting parameters, when experimental spectra are fitted with a hypothetical structure. The size of the supercell size limits the R-space range that these parameters could be used. Therefore corresponding DWFs for paths outside of this range are calculated using the correlated Debye model. Our method is compared with prior cluster calculations and with corresponding values obtained from fitting experimental XAFS spectra on manganosite with simulated spectra.

  17. NEXT GENERATION SOLVENT-MATERIALS COMPATIBILITY WITH POLYMER COMPONENTS WITHIN MODULAR CAUSTIC-SIDE SOLVENT EXTRACTION UNIT (FINAL REPORT)

    Energy Technology Data Exchange (ETDEWEB)

    Fondeur, F.; Peters, T.; Fink, S.

    2012-01-17

    The Office of Waste Processing, within the Office of Technology Innovation and Development, is funding the development of an enhanced solvent for deployment at the Savannah River Site for removal of cesium from High Level Waste. The technical effort is collaboration between Oak Ridge National Laboratory (ORNL), Savannah River National Laboratory (SRNL), and Argonne National Laboratory. The first deployment target for the technology is within the Modular Caustic-Side Solvent Extraction Unit (MCU). Deployment of a new chemical within an existing facility requires verification that the chemical components are compatible with the installed equipment. In the instance of a new organic solvent, the primary focus is on compatibility of the solvent with organic polymers used in the facility. This report provides the data from exposing these polymers to the Next Generation Solvent (NGS). The test was conducted over six months. An assessment of the dimensional stability of polymers present in MCU (i.e., PEEK, Grafoil, Tefzel and Isolast) in the modified NGS (where the concentration of LIX{reg_sign}79 and MaxCalix was varied systematically) showed that LIX{reg_sign}79 selectively affected Tefzel and its different grades (by an increase in size and lowering its density). The copolymer structure of Tefzel and possibly its porosity allows for the easier diffusion of LIX{reg_sign}79. Tefzel is used as the seat material in some of the valves at MCU. Long term exposure to LIX{reg_sign}79, may make the valves hard to operate over time due to the seat material (Tefzel) increasing in size. However, since the physical changes of Tefzel in the improved solvent are comparable to the changes in the CSSX baseline solvent, no design changes are needed with respect to the Tefzel seating material. PEEK, Grafoil and Isolast were not affected by LIX{reg_sign}79 and MaxCalix within six months of exposure. The initial rapid weight gain observed in every polymer is assigned to the finite and

  18. Dancing with Energetic Nitrogen Atoms: Versatile N-Functionalization Strategies for N-Heterocyclic Frameworks in High Energy Density Materials.

    Science.gov (United States)

    Yin, Ping; Zhang, Qinghua; Shreeve, Jean'ne M

    2016-01-19

    Nitrogen-rich heterocycles represent a unique class of energetic frameworks featuring high heats of formation and high nitrogen content, which have generated considerable research interest in the field of high energy density materials (HEDMs). Although traditional C-functionalization methodology of aromatic hydrocarbons has been fully established, studies on N-functionalization strategies of nitrogen-containing heterocycles still have great potential to be exploited by virtue of forming diverse N-X bonds (X = C, N, O, B, halogen, etc.), which are capable of regulating energy performance and the stability of the resulting energetic compounds. In this sense, versatile N-functionalization of N-heterocyclic frameworks offers a flexible strategy to meet the requirements of developing new-generation HEDMs. In this Account, the role of strategic N-functionalization in designing new energetic frameworks, including the formation of N-C, N-N, N-O, N-B and N-halogen bonds, is emphasized. In the family of N-functionalized HEDMs, energetic derivatives, by virtue of forming N-C bonds, are the most widely used type due to the good nucleophilic capacity of most heterocyclic backbones. Although introduction of carbon tends to decrease energetic performance, significant improvement in material sensitivity makes this strategy attractive for safety concerns. More importantly, most "explosophores" can be readily introduced into the N-C linkage, thus providing a promising route to various HEDMs. Formation of additional N-N bonds typically gives rise to higher heats of formation, implying the potential enhancement in detonation performance. In many cases, the increased hydrogen bonding interactions within N-N functionalized heterocycles also improve thermal stability accordingly. Introduction of a single N,N'-azo bridge into several azole moieties leads to an extended nitrogen chain, demonstrating a new strategy for designing high-nitrogen compounds. The strategy of N-O functionalization

  19. Insights into the crystal chemistry of Earth materials rendered by electron density distributions: Pauling's rules revisited

    Energy Technology Data Exchange (ETDEWEB)

    Gibbs, Gerald V.; Ross, Nancy L.; Cox, David F.; Rosso, Kevin M.

    2014-05-20

    coordination number of the atom is determined uniquely independent of the asphericity and sizes of the atom. A power law connection established between the bond lengths and bond strengths for crystals and molecules is mirrored by a comparable power law connection between bond length and the accumulation of the electron density between bonded pairs of atoms, a connection that is consistent with Pauling's electroneutrality postulate that the charges of the atoms in an oxide are negligibly small. The connection indicates that a one-to-one correspondence exists between the accumulation between a pair of bonded atoms and the Pauling bond strength for M-O bonded interaction for all atoms of the periodic table. The connection provides a common basis for understanding the success of the manifold applications that have been made with the bond valence theory model together with the modeling of crystal structures, chemical zoning, leaching and cation transport in batteries and the like. We believe that the wide spread applications of the model in mineralogy and material science owes much of its success to the direct connection between bond strength and the quantum mechanical observable, the electron density distribution. Comparable power law expressions established for the bonded interactions for both crystals and molecules support Pauling's assertion that his second rule has significance for molecules as well as for crystals. A simple expression is found that provides a one to one connection between the accumulation of the electron density between bonded M and O atoms and the Pauling bond strength for all M atoms of the periodic table with ~ 95 % of the variation of the bond strength being explained in terms of a linear dependence on the accumulated electron density. Compelling evidence is presented that supports the argument that the Si-O bonded interactions for tiny siloxane molecules and silicate crystals are chemically equivalent.

  20. A density functional theory study on the thermodynamic and dynamic properties of anthraquinone analogue cathode materials for rechargeable lithium ion batteries.

    Science.gov (United States)

    Yang, Shu-Jing; Qin, Xiao-Ya; He, Rongxing; Shen, Wei; Li, Ming; Zhao, Liu-Bin

    2017-05-21

    Organic redox compounds have become the emerging electrode materials for rechargeable lithium ion batteries. The high electrochemical performance provides organic electrode materials with great opportunities to be applied in electric energy storage devices. Among the different types of organic materials, conjugated carbonyl compounds are the most promising type at present, because only they can simultaneously achieve, high energy density, high cycling stability, and high power density. In this research, a series of heteroatom substituted anthraquinone (AQ) derivatives were designed theoretically so that the high theoretical capacity of AQ remained. The discharge and charge mechanism as well as the thermodynamic and dynamic properties of AQ and its derivatives were investigated using first-principles density functional theory. Using heteroatom substitution, both the thermodynamic and dynamic properties of AQ as cathode materials could be largely improved. Among these conjugated carboxyl compounds, BDOZD and BDIOZD with a simultaneously high theoretical capacity and high working potential exhibit the largest energy density of about 780 W h kg(-1), which is 41% larger than that of AQ. The PQD with the smallest value of λ gives the largest charge transfer rate constant, which is about four times as large as the prototype molecule, AQ. The most interesting finding is that the lithium ion transfer plays a very important role in influencing both the discharge potential and electrochemical charge transfer rate. The present study illustrates that theoretical calculations provide a highly effective way to discover potential materials for use with rechargeable lithium ion batteries.

  1. Sustainable Materials Management (SMM) Web Academy Webinar: Advancing Sustainable Materials Management: Facts and Figures 2013 - Assessing Trends in Materials Generation, Recycling and Disposal in the United States

    Science.gov (United States)

    This is a webinar page for the Sustainable Management of Materials (SMM) Web Academy webinar titled Let’s WRAP (Wrap Recycling Action Program): Best Practices to Boost Plastic Film Recycling in Your Community

  2. Comparison of United States and British Methods for Testing Plastic Materials

    Science.gov (United States)

    1976-09-01

    materials including cost, hot- molded and sheet materials. Two procedures, refractometric and microscopical, are proposed in order to cover satisfactorily...duplicability. The refractometric method, which is preferred, is based on the standard Abbe refractometer, almost universally used for liquids. For solids

  3. Motor unit properties in the biceps brachii of chronic stroke patients assessed with high-density surface EMG

    NARCIS (Netherlands)

    Kallenberg, L.A.C.; Hermens, Hermanus J.

    2009-01-01

    Motor unit properties of the biceps brachii and Fugl-Meyer score were assessed in stroke patients and healthy controls during passive and active elbow flexion and extension contractions. The level of motor recovery as assessed with the Fugl-Meyer was correlated with the ration of the size of the

  4. Materials

    Science.gov (United States)

    Glaessgen, Edward H.; Schoeppner, Gregory A.

    2006-01-01

    NASA Langley Research Center has successfully developed an electron beam freeform fabrication (EBF3) process, a rapid metal deposition process that works efficiently with a variety of weldable alloys. The EBF3 process can be used to build a complex, unitized part in a layer-additive fashion, although the more immediate payoff is for use as a manufacturing process for adding details to components fabricated from simplified castings and forgings or plate products. The EBF3 process produces structural metallic parts with strengths comparable to that of wrought product forms and has been demonstrated on aluminum, titanium, and nickel-based alloys to date. The EBF3 process introduces metal wire feedstock into a molten pool that is created and sustained using a focused electron beam in a vacuum environment. Operation in a vacuum ensures a clean process environment and eliminates the need for a consumable shield gas. Advanced metal manufacturing methods such as EBF3 are being explored for fabrication and repair of aerospace structures, offering potential for improvements in cost, weight, and performance to enhance mission success for aircraft, launch vehicles, and spacecraft. Near-term applications of the EBF3 process are most likely to be implemented for cost reduction and lead time reduction through addition of details onto simplified preforms (casting or forging). This is particularly attractive for components with protruding details that would require a significantly large volume of material to be machined away from an oversized forging, offering significant reductions to the buy-to-fly ratio. Future far-term applications promise improved structural efficiency through reduced weight and improved performance by exploiting the layer-additive nature of the EBF3 process to fabricate tailored unitized structures with functionally graded microstructures and compositions.

  5. Optimization of sintering conditions in bulk MgB{sub 2} material for improvement of critical current density

    Energy Technology Data Exchange (ETDEWEB)

    Muralidhar, M., E-mail: miryala1@shibaura-it.ac.jp [Superconducting Materials Laboratory, Department of Materials Science and Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548 (Japan); Nozaki, K.; Kobayashi, H. [Superconducting Materials Laboratory, Department of Materials Science and Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548 (Japan); Zeng, X.L.; Koblischka-Veneva, A.; Koblischka, M.R. [Experimental Physics, Saarland University, P.O. Box 151150, 66041 Saarbrücken (Germany); Inoue, K.; Murakami, M. [Superconducting Materials Laboratory, Department of Materials Science and Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548 (Japan)

    2015-11-15

    The present investigation focuses on methods to further improve the J{sub c} values of disk-shaped bulk MgB{sub 2} superconductors by optimizing the sintering conditions. We prepared two sets of bulk MgB{sub 2} material from commercial high-purity powders of Mg metal and amorphous B using a single-step solid-state reaction process. To optimize the sintering time, a set of samples was sintered at 775 °C with sintering duration ranging between 1 and 10 h (pure Ar atmosphere). A second set of samples was produced similarly at 775, 780, 785, 795, 800 and 805 °C (3 h, pure argon atmosphere). X-ray diffraction analysis showed that both sets of samples were single phase MgB{sub 2}. Magnetization measurements confirmed a sharp superconducting transition with T{sub c,onset} ≈ 38.2 K–38.8 K. The critical current density (J{sub c}) values for MgB{sub 2} samples produced for 1 h were the highest in all processed materials, i.e., the high J{sub c} value of 270,000 A/cm{sup 2} and 125,000 A/cm{sup 2} (20 K, self-field and 1 T) were achieved in the sample produced at 775 °C, without any additional doping. In contrast, the second series of samples clearly indicated that at 805 °C (3 h) the highest J{sub c} of 245,000 A/cm{sup 2} and 110,000 A/cm{sup 2} (20 K, self-field and 1 T) were achieved. AFM and EBSD observations indicated that largest amount of fine grains do exist in the sample sintered at 775 °C, but the narrowest distribution of grains does exist in the sample sintered at 800 °C. The present results clearly demonstrate a strong relation between the microstructure and the pinning performance. The optimization of the sintering conditions is crucial to improve the performance of bulk MgB{sub 2} samples. - Highlights: • We had successfully improved the performance of sintered, pure bulk MgB{sub 2} materials. • EBSD observations clarified that the grain sizes are in the 100–500 nm range. • The high J{sub c} value at 20 K, 0 T and 1 T are 2.70 × 10{sup 5} A

  6. High-density surface EMG decomposition allows for recording of motor unit discharge from proximal and distal flexion synergy muscles simultaneously in individuals with stroke.

    Science.gov (United States)

    Miller, Laura C; Thompson, Christopher K; Negro, Francesco; Heckman, C J; Farina, Dario; Dewald, Julius P A

    2014-01-01

    Analysis of motor unit discharge can provide insight into the neural control of movement in healthy and pathological states, but it is typically completed in one muscle at a time. For some research investigations, it would be advantageous to study motor unit discharge from multiple muscles simultaneously. One such example is investigation of the flexion synergy, an abnormal muscle co-activation pattern in post-stroke individuals in which activation of shoulder abductors is involuntarily coupled with that of elbow and finger flexors. However, limitations in available technology have hindered the ability to efficiently extract motor unit discharge from multiple muscles simultaneously. In this study, we propose the use of high-density surface EMG decomposition from proximal and distal flexion synergy muscles (deltoid, biceps, wrist/finger flexors) in combination with an isometric joint torque recording device in individuals with chronic stroke. This innovative approach provides the ability to efficiently analyze both motor units and joint torques that have been simultaneously recorded from the shoulder, elbow, and fingers. In preliminary experiments, 3 stroke and 5 control participants generated shoulder abduction, elbow flexion, and finger flexion torques at 10, 20, 30 and 40% of maximum torque. Motor unit spike trains could be extracted from all muscles at each torque level. Mean motor unit firing rates were significantly lower in the stroke group than in the control group for all three muscles. Within the stroke group, wrist/finger flexor motor units had the lowest coefficient of variation. Additionally, modulation of mean firing rates across torque levels was significantly impaired in all three paretic muscles. The implications of these findings and overall impact of this approach are discussed.

  7. Calibrating Reaction Enthalpies: Use of Density Functional Theory and the Correlation Consistent Composite Approach in the Design of Photochromic Materials.

    Science.gov (United States)

    Letterman, Roger G; DeYonker, Nathan J; Burkey, Theodore J; Webster, Charles Edwin

    2016-12-22

    Acquisition of highly accurate energetic data for chromium-containing molecules and various chromium carbonyl complexes is a major step toward calibrating bond energies and thermal isomerization energies from mechanisms for Cr-centered photochromic materials being developed in our laboratories. The performance of six density functionals in conjunction with seven basis sets, utilizing Gaussian-type orbitals, has been evaluated for the calculation of gas-phase enthalpies of formation and enthalpies of reaction at 298.15 K on various chromium-containing systems. Nineteen molecules were examined: Cr(CO)6, Cr(CO)5, Cr(CO)5(C2H4), Cr(CO)5(C2ClH3), Cr(CO)5(cis-(C2Cl2H2)), Cr(CO)5(gem-(C2Cl2H2)), Cr(CO)5(trans-(C2Cl2H2)), Cr(CO)5(C2Cl3H), Cr(CO)5(C2Cl4), CrO2, CrF2, CrCl2, CrCl4, CrBr2, CrBr4, CrOCl2, CrO2Cl2, CrOF2, and CrO2F2. The performance of 69 density functionals in conjunction with a single basis set utilizing Slater-type orbitals (STO) and a zeroth-order relativistic approximation was also evaluated for the same test set. Values derived from density functional theory were compared to experimental values where available, or values derived from the correlation consistent composite approach (ccCA). When all reactions were considered, the functionals that exhibited the smallest mean absolute deviations (MADs, in kcal mol(-1)) from ccCA-derived values were B97-1 (6.9), VS98 (9.0), and KCIS (9.4) in conjunction with quadruple-ζ STO basis sets and B97-1 (9.3) in conjunction with cc-pVTZ basis sets. When considering only the set of gas-phase reaction enthalpies (ΔrH°gas), the functional that exhibited the smallest MADs from ccCA-derived values were B97-1 in conjunction with cc-pVTZ basis sets (9.1) and PBEPBE in conjunction with polarized valence triple-ζ basis set/effective core potential combination for Cr and augmented and multiple polarized triple-ζ Pople style basis sets (9.5). Also of interest, certainly because of known cancellation of errors, PBEPBE with the

  8. Theoretical Studies of Possible Synthetic Routes for the High Energy Density Material Td N4: Excited Electronic States

    Science.gov (United States)

    Lee, Timothy J.; Dateo, Christopher E.

    2001-01-01

    Vertical electronic excitation energies for single states have been computed for the high energy density material (HEDM) Td N4 in order to assess possible synthetic routes that originate from excited electronic states of N2 molecules. Several ab initio theoretical approaches have been used, including complete active space self-consistent field (CASSCF), state averaged CASSCF (SA-CASSCF), singles configuration interaction (CIS), CIS with second-order and third-order correlation corrections [CIS(D)) and CIS(3)], and linear response singles and doubles coupled-cluster (LRCCSD), which is the highest level of theory employed. Standard double zeta polarized (DZP) and triple zeta double polarized (TZ2P) one-particle basis sets were used. The CASSCF calculations are found to overestimate the excitation energies, while the SA-CASSCF approach rectifies this error to some extent, but not completely. The accuracy of the CIS calculations varied depending on the particular state, while the CIS(D), CIS(3), and LRCCSD results are in generally good agreement. Based on the LRCCSD calculations, the lowest six excited singlet states are 9.35(l(sup)T1), 10.01(l(sup)T2), 10.04(1(sup)A2), 10.07(1(sup)E), 10.12(2(sup)T1), and 10.42(2(sup)T2) eV above the ground state, respectively. Comparison of these excited state energies with the energies of possible excited states of N2+N2 fragments, leads us to propose that the most likely synthetic route for Td N4 involving this mechanism arises from combination of two bound quintet states of N2.

  9. EnviroAtlas - Food, Fuel, and Materials Metrics for Conterminous United States

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas web service supports research and online mapping activities related to EnviroAtlas (https://www.epa.gov/enviroatlas). The Food, Fuel, and Materials...

  10. On the effective atomic number and electron density: A comprehensive set of formulas for all types of materials and energies above 1 keV

    DEFF Research Database (Denmark)

    Manohara, S.R.; Hanagodimath, S.M.; Thind, K.S.;

    2008-01-01

    A comprehensive and consistent set of formulas is given for calculating the effective atomic number and electron density for all types of materials and for all photon energies greater than 1 keV. The are derived from first principles using photon interaction cross sections of the constituent atoms...

  11. 76 FR 3307 - Hazardous Materials: Harmonization With the United Nations Recommendations, International...

    Science.gov (United States)

    2011-01-19

    ... communicate the hazards of hydrogen sulfide in the workplace. They supported other means of hazard... (FedEx); (9) Saft America, Inc. (Saft); (10) People for the Ethical Treatment of Animals (PETA); (11.... marking provides no additional value * * * because many people in the United States system will have no...

  12. The StreamCat Dataset: Accumulated Attributes for NHDPlusV2 (Version 2.1) Catchments Riparian Buffer for the Conterminous United States: 2010 US Census Housing Unit and Population Density

    Science.gov (United States)

    This dataset represents the population and housing unit density within individual, local NHDPlusV2 catchments and upstream, contributing watersheds riparian buffers based on 2010 US Census data. Densities are calculated for every block group and watershed averages are calculated for every local NHDPlusV2 catchment(see Data Sources for links to NHDPlusV2 data and Census Data). This data set is derived from The TIGER/Line Files and related database (.dbf) files for the conterminous USA. It was downloaded as Block Group-Level Census 2010 SF1 Data in File Geodatabase Format (ArcGIS version 10.0). The landscape raster (LR) was produced based on the data compiled from the questions asked of all people and about every housing unit. The (block-group population / block group area) and (block-group housing units / block group area) were summarized by local catchment and by watershed to produce local catchment-level and watershed-level metrics as a continuous data type (see Data Structure and Attribute Information for a description).

  13. The StreamCat Dataset: Accumulated Attributes for NHDPlusV2 Catchments (Version 2.1) for the Conterminous United States: 2010 US Census Housing Unit and Population Density

    Science.gov (United States)

    This dataset represents the population and housing unit density within individual, local NHDPlusV2 catchments and upstream, contributing watersheds based on 2010 US Census data. Densities are calculated for every block group and watershed averages are calculated for every local NHDPlusV2 catchment(see Data Sources for links to NHDPlusV2 data and Census Data). This data set is derived from The TIGER/Line Files and related database (.dbf) files for the conterminous USA. It was downloaded as Block Group-Level Census 2010 SF1 Data in File Geodatabase Format (ArcGIS version 10.0). The landscape raster (LR) was produced based on the data compiled from the questions asked of all people and about every housing unit. The (block-group population / block group area) and (block-group housing units / block group area) were summarized by local catchment and by watershed to produce local catchment-level and watershed-level metrics as a continuous data type (see Data Structure and Attribute Information for a description). Using a riparian buffer(see Process Steps), statistics were generated for areas within each catchment that are within 100 meters of the stream reach in an attempt to evaluate for the riparian zone.

  14. Monte carlo simulation of innovative neutron and photon shielding material composing of high density concrete, waste rubber, lead and boron carbide

    Science.gov (United States)

    Aim-O, P.; Wongsawaeng, D.; Phruksarojanakun, P.; Tancharakorn, S.

    2017-06-01

    High-density concrete exhibits high strength and can perform an important role of gamma ray attenuation. In order to upgrade this material’s radiation-shielding performance, hydrogen-rich material can be incorporated. Waste rubber from vehicles has high hydrogen content which is the prominent characteristic to attenuate neutron. The objective of this work was to evaluate the radiation-shielding properties of this composite material against neutron and photon radiations. Monte Carlo transport simulation was conducted to simulate radiation through the composite material. Am-241/Be was utilized for neutron source and Co-60 for photon source. Parameters of the study included volume percentages of waste rubber, lead and boron carbide and thickness of the shielding material. These designs were also fabricated and the radiation shielding properties were experimentally evaluated. The best neutron and gamma ray shielding material was determined to be high-density concrete mixed with 5 vol% crumb rubber and 5 vol% lead powder. This shielding material increased the neutron attenuation by 64% and photon attenuation by 68% compared to ordinary concrete. Also, increasing the waste rubber content to greater than 5% resulted in a decrease in the radiation attenuation. This innovative composite radiation shielding material not only benefits nuclear science and engineering applications, but also helps solve the environmental issue of waste rubber.

  15. Temperature changes under demineralized dentin during polymerization of three resin-based restorative materials using QTH and LED units

    Directory of Open Access Journals (Sweden)

    Sayed-Mostafa Mousavinasab

    2014-08-01

    Full Text Available Objectives Light-curing of resin-based materials (RBMs increases the pulp chamber temperature, with detrimental effects on the vital pulp. This in vitro study compared the temperature rise under demineralized human tooth dentin during light-curing and the degrees of conversion (DCs of three different RBMs using quartz tungsten halogen (QTH and light-emitting diode (LED units (LCUs. Materials and Methods Demineralized and non-demineralized dentin disks were prepared from 120 extracted human mandibular molars. The temperature rise under the dentin disks (n = 12 during the light-curing of three RBMs, i.e. an Ormocer-based composite resin (Ceram. X, Dentsply DeTrey, a low-shrinkage silorane-based composite (Filtek P90, 3M ESPE, and a giomer (Beautifil II, Shofu GmbH, was measured with a K-type thermocouple wire. The DCs of the materials were investigated using Fourier transform infrared spectroscopy. Results The temperature rise under the demineralized dentin disks was higher than that under the non-demineralized dentin disks during the polymerization of all restorative materials (p 0.05. Conclusions Although there were no significant differences in the DCs, the temperature rise under demineralized dentin disks for the silorane-based composite was higher than that for dimethacrylate-based restorative materials, particularly with QTH LCU.

  16. Instructional materials in a STSE perspective: an analisys of units produced by secondary chemistry teachers in continuant formation

    Directory of Open Access Journals (Sweden)

    Maria Eunice Ribeiro Marcondes

    2009-10-01

    Full Text Available Some research has shown that teachers present conceptions that indicate a vision of teaching focused on memorization and transmission of knowledge and do not consider an approach that regards to the STSE aspects. The aim of this study is to investigate the conceptions of contextualization present in instructional materials produced by a group of chemistry secondary teachers. The data were collected in a service course offered to teachers of São Paulo Metropolitan area. One of the strategies of the course was the production of instructional units based on STSE (Science, Technology, Society and Environment orientations. The data analysis takes into account: presence of problematization, its development throughout the unit; the relations established between experiments or text and the proposed theme, and the nature of information presented in the texts (scientific, social, technological, environmental. Four context profiles were built to characterize the 13 units elaborated by the teachers. Four of the teachers’ units revealed simple contextualization view profiles, although six of them revealed more complex profiles, compatible with STSE orientation.

  17. Examples of density, orientation and shape optimal design for stiffness and/or strength with orthotropic materials

    DEFF Research Database (Denmark)

    Pedersen, Pauli

    2004-01-01

    a penalization approach to obtain "black and white" designs, i.e. uniform material or holes, is often applied in optimal design. A specific example is studied to show the effect of the penalization, but is restricted here to an isotropic material. When the total amount of material is not specified, a conflict...

  18. A Brief Assessment of Structural Composite Materials Research in Universities in the United States.

    Science.gov (United States)

    1985-12-01

    composites. ’ 2. Improved techniques are strongly needed in nondestructive evaluation ( NDE ). 3. Combination of NDE , pattern recognition, artificial...Santa Barbara. California 93106 Dean, College of Engineering (905) 961-3141 August 20, 1985 9_. Dr. Ben Wilcox Assistant Director Materials Science

  19. Biomass and carbon attributes of downed woody materials in forests of the United States

    Science.gov (United States)

    C.W. Woodall; B.F. Walters; S.N. Oswalt; G.M. Domke; C. Toney; A.N. Gray

    2013-01-01

    Due to burgeoning interest in the biomass/carbon attributes of forest downed and dead woody materials (DWMs) attributable to its fundamental role in the carbon cycle, stand structure/diversity, bioenergy resources, and fuel loadings, the U.S. Department of Agriculture has conducted a nationwide field-based inventory of DWM. Using the national DWM inventory, attributes...

  20. Rechargeable Biofilm-Controlling Tubing Materials for Use in Dental Unit Water Lines

    OpenAIRE

    Luo, Jie; Porteous, Nuala; Sun, Yuyu

    2011-01-01

    A simple and practical surface grafting approach was developed to introduce rechargeable N-halamine-based antimicrobial functionality onto the inner surfaces of continuous small-bore polyurethane (PU) dental unit waterline (DUWL) tubing. In this approach, tetrahydrofuran (THF) solution of a free-radical initiator, dicumyl peroxide (DCP), flowed through the PU tubing (inner diameter of 1/16 inch, or 1.6 mm) to diffuse DCP into the tube’s inner walls, which was used as initiator in the subseque...

  1. Integration of high capacity materials into interdigitated mesostructured electrodes for high energy and high power density primary microbatteries

    Science.gov (United States)

    Pikul, James H.; Liu, Jinyun; Braun, Paul V.; King, William P.

    2016-05-01

    Microbatteries are increasingly important for powering electronic systems, however, the volumetric energy density of microbatteries lags behind that of conventional format batteries. This paper reports a primary microbattery with energy density 45.5 μWh cm-2 μm-1 and peak power 5300 μW cm-2 μm-1, enabled by the integration of large volume fractions of high capacity anode and cathode chemistry into porous micro-architectures. The interdigitated battery electrodes consist of a lithium metal anode and a mesoporous manganese oxide cathode. The key enabler of the high energy and power density is the integration of the high capacity manganese oxide conversion chemistry into a mesostructured high power interdigitated bicontinuous cathode architecture and an electrodeposited dense lithium metal anode. The resultant energy density is greater than previously reported three-dimensional microbatteries and is comparable to commercial conventional format lithium-based batteries.

  2. Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States: Model of predicted nitrate concentration in shallow, recently recharged ground water -- Input data set for population density (gwava-s_popd)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents 1990 block group population density, in people per square kilometer, in the conterminous United States. The data set was used as an input...

  3. Strategic Consolidation of Medical War Reserve Material (WRM) Equipment Unit Type Code (UTC) Assemblages

    Science.gov (United States)

    2013-03-01

    location data was extracted from Excel and uploaded into the optimization modeling software LINGO . Once the objective function and constraints were...created with VBA and uploaded into LINGO as well, the software program provided the minimized cost and UTC movements and exported the results into a text...region there would still be the risk of a single event incapacitating all material. Multi-site Once the VBA code was written to allow LINGO to

  4. Ultrahigh energy density Li-ion batteries based on cathodes of 1D metals with –Li–N–B–N– repeating units in α-Li{sub x}BN{sub 2} (1 ⩽ x ⩽ 3)

    Energy Technology Data Exchange (ETDEWEB)

    Németh, Károly, E-mail: nemeth@agni.phys.iit.edu [Physics Department, Illinois Institute of Technology, Chicago, Illinois 60616 (United States)

    2014-08-07

    Ultrahigh energy density batteries based on α-Li{sub x}BN{sub 2} (1 ⩽ x ⩽ 3) positive electrode materials are predicted using density functional theory calculations. The utilization of the reversible LiBN{sub 2} + 2 Li{sup +} + 2 e{sup −} ⇌ Li{sub 3}BN{sub 2} electrochemical cell reaction leads to a voltage of 3.62 V (vs Li/Li{sup +}), theoretical energy densities of 3251 Wh/kg and 5927 Wh/l, with capacities of 899 mAh/g and 1638 mAh/cm{sup 3}, while the cell volume of α-Li{sub 3}BN{sub 2} shrinks only 2.8% per two-electron transfer on charge. These values are far superior to the best existing or theoretically designed intercalation or conversion-based positive electrode materials. For comparison, the theoretical energy density of a Li–O{sub 2}/peroxide battery is 3450 Wh/kg (including the weight of O{sub 2}), that of a Li–S battery is 2600 Wh/kg, that of Li{sub 3}Cr(BO{sub 3})(PO{sub 4}) (one of the best designer intercalation materials) is 1700 Wh/kg, while already commercialized LiCoO{sub 2} allows for 568 Wh/kg. α-Li{sub 3}BN{sub 2} is also known as a good Li-ion conductor with experimentally observed 3 mS/cm ionic conductivity and 78 kJ/mol (≈0.8 eV) activation energy of conduction. The attractive features of α-Li{sub x}BN{sub 2} (1 ⩽ x ⩽ 3) are based on a crystal lattice of 1D conjugated polymers with –Li–N–B–N– repeating units. When some of the Li is deintercalated from α-Li{sub 3}BN{sub 2} the crystal becomes a metallic electron conductor, based on the underlying 1D conjugated π electron system. Thus, α-Li{sub x}BN{sub 2} (1 ⩽ x ⩽ 3) represents a new type of 1D conjugated polymers with significant potential for energy storage and other applications.

  5. Association of proximity and density of parks and objectively measured physical activity in the United States: A systematic review.

    Science.gov (United States)

    Bancroft, Carolyn; Joshi, Spruha; Rundle, Andrew; Hutson, Malo; Chong, Catherine; Weiss, Christopher C; Genkinger, Jeanine; Neckerman, Kathryn; Lovasi, Gina

    2015-08-01

    One strategy for increasing physical activity is to create and enhance access to park space. We assessed the literature on the relationship of parks and objectively measured physical activity in population-based studies in the United States (US) and identified limitations in current built environment and physical activity measurement and reporting. Five English-language scholarly databases were queried using standardized search terms. Abstracts were screened for the following inclusion criteria: 1) published between January 1990 and June 2013; 2) US-based with a sample size greater than 100 individuals; 3) included built environment measures related to parks or trails; and 4) included objectively measured physical activity as an outcome. Following initial screening for inclusion by two independent raters, articles were abstracted into a database. Of 10,949 abstracts screened, 20 articles met the inclusion criteria. Five articles reported a significant positive association between parks and physical activity. Nine studies found no association, and six studies had mixed findings. Our review found that even among studies with objectively measured physical activity, the association between access to parks and physical activity varied between studies, possibly due to heterogeneity of exposure measurement. Self-reported (vs. independently-measured) neighborhood park environment characteristics and smaller (vs. larger) buffer sizes were more predictive of physical activity. We recommend strategies for further research, employing standardized reporting and innovative study designs to better understand the relationship of parks and physical activity.

  6. Transient Testing of Nuclear Fuels and Materials in the United States

    Science.gov (United States)

    Wachs, Daniel M.

    2012-12-01

    The United States has established that transient irradiation testing is needed to support advanced light water reactors fuel development. The U.S. Department of Energy (DOE) has initiated an effort to reestablish this capability. Restart of the Transient Testing Reactor (TREAT) facility located at the Idaho National Laboratory (INL) is being considered for this purpose. This effort would also include the development of specialized test vehicles to support stagnant capsule and flowing loop tests as well as the enhancement of postirradiation examination capabilities and remote device assembly capabilities at the Hot Fuel Examination Facility. It is anticipated that the capability will be available to support testing by 2018, as required to meet the DOE goals for the development of accident-tolerant LWR fuel designs.

  7. Variable Density Flow Modeling for Simulation Framework for Regional Geologic CO{sub 2} Storage Along Arches Province of Midwestern United States

    Energy Technology Data Exchange (ETDEWEB)

    Joel Sminchak

    2011-09-30

    The Arches Province in the Midwestern U.S. has been identified as a major area for carbon dioxide (CO{sub 2}) storage applications because of the intersection of Mt. Simon sandstone reservoir thickness and permeability. To better understand large-scale CO{sub 2} storage infrastructure requirements in the Arches Province, variable density scoping level modeling was completed. Three main tasks were completed for the variable density modeling: Single-phase, variable density groundwater flow modeling; Scoping level multi-phase simulations; and Preliminary basin-scale multi-phase simulations. The variable density modeling task was successful in evaluating appropriate input data for the Arches Province numerical simulations. Data from the geocellular model developed earlier in the project were translated into preliminary numerical models. These models were calibrated to observed conditions in the Mt. Simon, suggesting a suitable geologic depiction of the system. The initial models were used to assess boundary conditions, calibrate to reservoir conditions, examine grid dimensions, evaluate upscaling items, and develop regional storage field scenarios. The task also provided practical information on items related to CO{sub 2} storage applications in the Arches Province such as pressure buildup estimates, well spacing limitations, and injection field arrangements. The Arches Simulation project is a three-year effort and part of the United States Department of Energy (U.S. DOE)/National Energy Technology Laboratory (NETL) program on innovative and advanced technologies and protocols for monitoring/verification/accounting (MVA), simulation, and risk assessment of CO{sub 2} sequestration in geologic formations. The overall objective of the project is to develop a simulation framework for regional geologic CO{sub 2} storage infrastructure along the Arches Province of the Midwestern U.S.

  8. B-vitamin status and bone mineral density and risk of lumbar osteoporosis in older females in the United States.

    Science.gov (United States)

    Bailey, Regan L; Looker, Anne C; Lu, Zhaohui; Fan, Ruzong; Eicher-Miller, Heather A; Fakhouri, Tala H; Gahche, Jaime J; Weaver, Connie M; Mills, James L

    2015-09-01

    Previous data suggest that elevated serum total homocysteine (tHcy) may be a risk factor for bone fracture and osteoporosis. Nutritional causes of elevated tHcy are suboptimal B-vitamin status. To our knowledge, this is the first nationally representative report on the relation of B vitamins and bone health from a population with folic acid fortification. The purpose of this analysis was to examine the relation between B-vitamin status biomarkers and bone mineral density (BMD), risk of osteoporosis, and biomarkers of bone turnover. We examined the relation of tHcy, methylmalonic acid (MMA), and serum/red blood cell folate and total-body and lumbar spine BMD in women aged ≥50 y participating in the NHANES 1999-2004 (n = 2806), a nationally representative cross-sectional survey. These are the only years with concurrent measurement of tHcy and whole-body dual-energy X-ray absorptiometry. We also examined B-vitamin biomarkers relative to bone turnover markers, bone alkaline phosphatase, and urinary N-terminal cross-linked telopeptide of type I collagen in a 1999-2002 subset with available data (n = 1813). In comparison with optimal concentrations, women with elevated tHcy were older with lower serum vitamin B-12, red blood cell folate, and dietary micronutrient intakes and had significantly higher mean ± SE markers of bone turnover (bone alkaline phosphatase: 15.8 ± 0.59 compared with 14.0 ± 0.25 μg/L; urinary N-terminal cross-linked telopeptide of type I collagen: 48.2 ± 2.9 compared with 38.9 ± 0.90 nmol bone collagen equivalents per mmol creatinine/L). Elevated MMA (OR: 1.88; 95% CI: 1.10, 3.18) and tHcy (OR: 2.17; 95% CI: 1.14, 4.15) were related to increased risk of lumbar osteoporosis. When examined as a continuous variable, tHcy was negatively associated, serum folates were positively associated, and MMA and vitamin B-12 were not significantly associated with lumbar and total-body BMD. In this nationally representative population of older US women with

  9. Structure factor of blends of solvent-free nanoparticle–organic hybrid materials: density-functional theory and small angle X-ray scattering

    KAUST Repository

    Yu, Hsiu-Yu

    2014-09-15

    © the Partner Organisations 2014. We investigate the static structure factor S(q) of solvent-free nanoparticle-organic hybrid materials consisting of silica nanocores and space-filling polyethylene glycol coronas using a density-functional theory and small angle X-ray scattering measurements. The theory considers a bidisperse suspension of hard spheres with different radii and tethered bead-spring oligomers with different grafting densities to approximate the polydispersity effects in experiments. The experimental systems studied include pure samples with different silica core volume fractions and the associated mean corona grafting densities, and blends with different mixing ratios of the pure samples, in order to introduce varying polydispersity of corona grafting density. Our scattering experiments and theory show that, compared to the hard-sphere suspension with the same core volume fraction, S(q) for pure samples exhibit both substantially smaller values at small q and stronger particle correlations corresponding to a larger effective hard core at large q, indicating that the tethered incompressible oligomers enforce a more uniform particle distribution, and the densely grafted brush gives rise to an additional exclusionary effect between the nanoparticles. According to the theory, polydispersity in the oligomer grafting density controls the deviation of S(q) from the monodisperse system at smaller q, and the interplay of the enhanced effective core size and the entropic attraction among the particles is responsible for complex variations in the particle correlations at larger q. The successful comparison between the predictions and the measurements for the blends further suggests that S(q) can be used to assess the uniformity of grafting density in polymer-grafted nanoparticle materials. This journal is

  10. Concentration and risk of pharmaceuticals in freshwater systems are related to the population density and the livestock units in Iberian Rivers.

    Science.gov (United States)

    Osorio, Victoria; Larrañaga, Aitor; Aceña, Jaume; Pérez, Sandra; Barceló, Damià

    2016-01-01

    , gemfibrozil and loratidine were identified as the more concerning compounds. Significantly positive relationships were found among levels of pharmaceuticals and toxic units and population density and livestock units in both surface water and sediment matrices. Copyright © 2015. Published by Elsevier B.V.

  11. Nanocluster metal films as thermoelectric material for radioisotope mini battery unit

    Science.gov (United States)

    Borisyuk, P. V.; Krasavin, A. V.; Tkalya, E. V.; Lebedinskii, Yu. Yu.; Vasiliev, O. S.; Yakovlev, V. P.; Kozlova, T. I.; Fetisov, V. V.

    2016-10-01

    The paper is devoted to studying the thermoelectric and structural properties of films based on metal nanoclusters (Au, Pd, Pt). The experimental results of the study of single nanoclusters' tunneling conductance obtained with scanning tunneling spectroscopy are presented. The obtained data allowed us to evaluate the thermoelectric power of thin film consisting of densely packed individual nanoclusters. It is shown that such thin films can operate as highly efficient thermoelectric materials. A scheme of miniature thermoelectric radioisotope power source based on the thorium-228 isotope is proposed. The efficiency of the radioisotope battery using thermoelectric converters based on nanocluster metal films is shown to reach values up to 1.3%. The estimated characteristics of the device are comparable with the parameters of up-to-date radioisotope batteries based on nickel-63.

  12. Fracture Strength of Three-Unit Implant Supported Fixed Partial Dentures with Excessive Crown Height Fabricated from Different Materials

    Directory of Open Access Journals (Sweden)

    Vahideh Nazari

    2017-01-01

    Full Text Available Objectives: Fracture strength is an important factor influencing the clinical long-term success of implant-supported prostheses especially in high stress situations like excessive crown height space (CHS. The purpose of this study was to compare the fracture strength of implant-supported fixed partial dentures (FPDs with excessive crown height, fabricated from three different materials.Materials and Methods: Two implants with corresponding abutments were mounted in a metal model that simulated mandibular second premolar and second molar. Thirty 3-unit frameworks with supportive anatomical design were fabricated using zirconia, nickel-chromium alloy (Ni-Cr, and polyetheretherketone (PEEK (n=10. After veneering, the CHS was equal to 15mm. Then; samples were axially loaded on the center of pontics until fracture in a universal testing machine at a crosshead speed of 0.5 mm/minute. The failure load data were analyzed by one-way ANOVA and Games-Howell tests at significance level of 0.05.Results: The mean failure loads for zirconia, Ni-Cr and PEEK restorations were 2086±362N, 5591±1200N and 1430±262N, respectively. There were significant differences in the mean failure loads of the three groups (P<0.001. The fracture modes in zirconia, metal ceramic and PEEK restorations were cohesive, mixed and adhesive type, respectively.Conclusions: According to the findings of this study, all implant supported three-unit FPDs fabricated of zirconia, metal ceramic and PEEK materials are capable to withstand bite force (even para-functions in the molar region with excessive CHS.Keywords: Dental Implants; Polyetheretherketone; Zirconium oxide; Dental Restoration Failure; Dental Porcelain

  13. Fracture Strength of Three-Unit Implant Supported Fixed Partial Dentures with Excessive Crown Height Fabricated from Different Materials

    Science.gov (United States)

    Nazari, Vahideh; Ghodsi, Safoura; Alikhasi, Marzieh; Shamshiri, Ahmad Reza

    2016-01-01

    Objectives: Fracture strength is an important factor influencing the clinical long-term success of implant-supported prostheses especially in high stress situations like excessive crown height space (CHS). The purpose of this study was to compare the fracture strength of implant-supported fixed partial dentures (FPDs) with excessive crown height, fabricated from three different materials. Materials and Methods: Two implants with corresponding abutments were mounted in a metal model that simulated mandibular second premolar and second molar. Thirty 3-unit frameworks with supportive anatomical design were fabricated using zirconia, nickel-chromium alloy (Ni-Cr), and polyetheretherketone (PEEK) (n=10). After veneering, the CHS was equal to 15mm. Then; samples were axially loaded on the center of pontics until fracture in a universal testing machine at a crosshead speed of 0.5 mm/minute. The failure load data were analyzed by one-way ANOVA and Games-Howell tests at significance level of 0.05. Results: The mean failure loads for zirconia, Ni-Cr and PEEK restorations were 2086±362N, 5591±1200N and 1430±262N, respectively. There were significant differences in the mean failure loads of the three groups (Pzirconia, metal ceramic and PEEK restorations were cohesive, mixed and adhesive type, respectively. Conclusions: According to the findings of this study, all implant supported three-unit FPDs fabricated of zirconia, metal ceramic and PEEK materials are capable to withstand bite force (even para-functions) in the molar region with excessive CHS. PMID:28243301

  14. Analysis of factors influence the power density of light curing units%光固化灯功率密度的影响因素分析

    Institute of Scientific and Technical Information of China (English)

    邓淑丽; 李聪; 朱海华; 陈晖

    2012-01-01

    Objective To analyze factors that influence the power density of light curing units.Methods The power density values of 104 curing-light units from two dental hospitals in Hangzhou were investigated.Three lights among them with different power density were used to project to the radiometer sensor at different distances and angles.The power density was measured also when the curing tips were coated with protective sleeve or not.Results The values of power density were from 0 to 1180 mW/cm2.The mean power density was (519.7 ± 294.5) mW/cm2.With the curing distance increasing,the power densities were decreased significantly (P < 0.05).When the distance was 8 mm,the power densities were (545.7 ± 25.1),(448.0 ± 22.7) and (200.0 ± 7.5) mW/cm2.The power densities decreased to (269.0 ± 3.0),(265.3 ± 26.8) and (129.7 ± 4.7) mW/cm2 as the projecting angle increased to 60°.There was statistically significant difference in power density between the curing tips with or without protective sleeve (P < 0.05).Conclusions The factors that influence power density of light-curing units were the curing distance,projected angle and protective sleeve.%目的 分析复合树脂充填治疗中可能影响复合树脂固化的光固化灯的使用因素,为临床选择合适的光固化灯提供参考.方法 调查杭州市两家口腔专科医院104盏临床使用的光固化灯的功率密度及相关信息;对其中3盏不同功率密度的光固化灯(分别为1、2、3号灯)以不同距离和角度照射及光固化灯使用不同防护套前、后功率密度的变化进行对比分析.结果 104盏光固化灯的功率密度范围为0 ~ 1180 mW/cm2,平均值为(519.7±294.5) mW/cm2.随着光固化灯光导棒照射距离和角度的增加,辐射仪感应窗测得的功率密度值降低,当照射距离增加至8 mm时,1、2、3号灯的功率密度值分别从(1133.7±17.6)、(895.3±7.4)、(401.3±6.0) mW/cm2下降为(545.7±25.1)、(448.0±22.7)、(200.0±7.5) m

  15. Dual-energy X-ray absorptiometry for the simultaneous determination of Density and Moisture Content in Porous Structural Materials

    DEFF Research Database (Denmark)

    Hansen, Kurt Kielsgaard; Jensen, Signe Kamp; Gerward, Leif

    1999-01-01

    The paper describes the dual-energy x-ray equipment, which consists of a x-ray source, filters and a detector. The x-ray beam can be moved automatically in two dimensions relative to a fixed specimen. The purpose of the equipment is to measure simultaneously the density and moisture content...

  16. Density functional theory based screening of ternary alkali-transition metal borohydrides: A computational material design project

    DEFF Research Database (Denmark)

    Hummelshøj, Jens Strabo; Landis, David; Voss, Johannes

    2009-01-01

    We present a computational screening study of ternary metal borohydrides for reversible hydrogen storage based on density functional theory. We investigate the stability and decomposition of alloys containing 1 alkali metal atom, Li, Na, or K (M1); and 1 alkali, alkaline earth or 3d/4d transition...

  17. SYNCHROTRON-RADIATION X-RAY-DIFFRACTION OF MODULATED STRUCTURES IN CHARGE-DENSITY-WAVE MATERIALS - APPLICATION TO NBSE3

    NARCIS (Netherlands)

    VANSMAALEN, S; DEBOER, JL; COPPENS, P

    1993-01-01

    Synchrotron radiation X-ray diffraction has been performed on niobium triselenide at 20K. The modulation parameters belonging to both Charge-Density-Waves (CDW's) have been determined. The high-temperature CDW is found to comprise of displacements on all atoms of column III, as well as on Se atoms o

  18. Parallel Two-Electron Reduced Density Matrix Based Electronic Structure Software for Highly Correlated Molecules and Materials

    Science.gov (United States)

    2015-04-07

    units (GPUs), which are automatically detected and utilized by our software (if the software is configured with a “ cuda ” option). Figure 5 provides...library (for the diagonalization) and the cublasDgemm call of the NVIDIA CUDA Basic Linear Algebra Subroutine (cuBLAS) library (for the transformation

  19. Flammability of radiation cross-linked low density polyethylene as an insulating material for wire and cable

    Science.gov (United States)

    Basfar, A. A.

    2002-03-01

    Various formulations of low-density polyethylene blended with ethylene vinyl acetate were prepared to improve the flame retardancy for wire and cable applications. The prepared formulations were cross-linked by γ-rays to 50, 100, 150 and 200 kGy in the presence of trimethylolpropane triacrylate (TMPTA). The effect of thermal aging on mechanical properties of these formulations were investigated. In addition, the influence of various combinations of aluminum trihydroxide and zinc borate as flame retardant fillers on the flammability was explored. Limiting oxygen index (LOI) and average extent of burning were used to characterize the flammability of investigated formulations. An improved flame retardancy of low density polyethylene was achieved by various combinations of flame ratardant fillers and cross-linking by gamma radiation.

  20. Surface layer structure and average contact temperature of copper-containing materials under dry sliding with high electric current density

    Science.gov (United States)

    Fadin, V. V.; Aleutdinova, M. I.; Rubtsov, V. Ye.; Aleutdinov, K. A.

    2016-11-01

    Dry sliding of copper and powder composites of Cu-Fe and Cu-Fe-graphite compositions against 1045 steel under electric current of contact density higher than 250 A/cm2 has been studied, which demonstrated the change in surface layer structure and formation of tribolayer consisting of iron, copper and FeO oxide. Signs of quasi-viscous flow of worn surface were observed. It was noted that the thin contact layer containing about 40 at % of oxygen and 40% of Fe was the main factor decreasing the adhesion interaction. It was affirmed that the introduction of graphite into the primary structure of the composite leads to rather low content of FeO oxide and to the increased tendency of surface layer to catastrophic deterioration under sliding with contact current density of about 300 A/cm2. The temperature of contact did not exceed 400°C.

  1. Electronic and atomic structures of the Sr3Ir4Sn13 single crystal: A possible charge density wave material

    Science.gov (United States)

    Wang, H.-T.; Srivastava, M. K.; Wu, C.-C.; Hsieh, S.-H.; Wang, Y.-F.; Shao, Y.-C.; Liang, Y.-H.; Du, C.-H.; Chiou, J.-W.; Cheng, C.-M.; Chen, J.-L.; Pao, C.-W.; Lee, J.-F.; Kuo, C. N.; Lue, C. S.; Wu, M.-K.; Pong, W.-F.

    2017-01-01

    X-ray scattering (XRS), x-ray absorption near-edge structure (XANES) and extended x-ray absorption fine structure (EXAFS) spectroscopic techniques were used to study the electronic and atomic structures of the high-quality Sr3Ir4Sn13 (SIS) single crystal below and above the transition temperature (T* ≈ 147 K). The evolution of a series of modulated satellite peaks below the transition temperature in the XRS experiment indicated the formation of a possible charge density wave (CDW) in the (110) plane. The EXAFS phase derivative analysis supports the CDW-like formation by revealing different bond distances [Sn1(2)-Sn2] below and above T* in the (110) plane. XANES spectra at the Ir L3-edge and Sn K-edge demonstrated an increase (decrease) in the unoccupied (occupied) density of Ir 5d-derived states and a nearly constant density of Sn 5p-derived states at temperatures T atomic structures and the CDW-like phase in the SIS single crystal. PMID:28106144

  2. Synthesis and properties of two novel copolymers based on squaraine and fluorene units for solar cell materials

    Institute of Scientific and Technical Information of China (English)

    Zheng Wang; Wei Zhang; Feng Tao; Kai Ge Meng; Long Yi Xi; Ying Li; Qing Jiang

    2011-01-01

    Two novel copolymers based on squaraine and fluorine units have been synthesized through palladium catalyzed Suzuki coupling reaction and Sonogashira coupling reaction, respectively. The structures and properties of the two copolymers were characterized by FT-IR, NMR, UV-vis absorbance (Abs), gel permeation chromatography (GPC), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and cyclic voltammetry (CV). The solution absorption spectrums of P1 and P2 show two distinct absorption bands, one locates at 300-500 nm and the other at 600-800 nm. The absorption spectrums of P1 and P2 in films are broadened obviously and the spectral responses are extended up to 900 nm. Thermal gravimetric analysis demonstrates that the polymers are stable. Cyclic voltammetry experiment shows that the band gaps of the copolymers are 1.65 eV and 1.67 eV, respectively, suggesting their potential for applications as solar cells materials.

  3. 复合材料飞轮结构与储能密度%COMPOSITE MATERIAL FLYWHEEL STRUCTURE AND ENERGY-S TORING DENSITY

    Institute of Scientific and Technical Information of China (English)

    李文超; 沈祖培

    2001-01-01

    为提高飞轮的储能密度,需采用合适的转子材料和合理的转子结构。复合材料与各向同性材料相比具有明显优势。多层转子结构突破了单层转子内外半径比的限制,可明显改善转子内部的应力分布,提高飞轮的储能密度。该文论述了复合材料飞轮储能密度的影响因素,对复合材料转子的应力分布作了定量分析,比较了单层和多层转子的特点,综合考虑飞轮设计的各种因素,提出了飞轮转子结构参数的设计方法。%In order to increase energy-storin g density offlywheel,appropriate rotor material and reasonable structure should be used.Co mpared with isotropic materials,the composite material has evident advantages.M u lti-ring rotor structure breaks through restriction of the ratio of inner radii to outer radii,which can evidently improve the distribution of rotor stress and incre ase flywheel energy-storing density.This paper discusses the influence factor i n the energy-storing density of composite flywheel,quantificationally analyzes the stress distribution of composite material rotor,and compared the characteris tics of single-ring with multi-ring rotor.Synthetically considering all these factors,the design method of flywheel rotor structure parameters was put forward

  4. Trigonal Planar [HgSe3](4-) Unit: A New Kind of Basic Functional Group in IR Nonlinear Optical Materials with Large Susceptibility and Physicochemical Stability.

    Science.gov (United States)

    Li, Chao; Yin, Wenlong; Gong, Pifu; Li, Xiaoshuang; Zhou, Molin; Mar, Arthur; Lin, Zheshuai; Yao, Jiyong; Wu, Yicheng; Chen, Chuangtian

    2016-05-18

    A new mercury selenide BaHgSe2 was synthesized. This air-stable compound displays a large nonlinear optical (NLO) response and melts congruently. The structure contains chains of corner-sharing [HgSe3](4-) anions in the form of trigonal planar units, which may serve as a new kind of basic functional group in IR NLO materials to confer large NLO susceptibilities and physicochemical stability. Such trigonal planar units may inspire a path to finding new classes of IR NLO materials of practical utility that are totally different from traditional chalcopyrite materials.

  5. An analysis of the impact of native oxide, surface contamination and material density on total electron yield in the absence of surface charging effects

    Science.gov (United States)

    Iida, Susumu; Ohya, Kaoru; Hirano, Ryoichi; Watanabe, Hidehiro

    2016-10-01

    The effects of the presence of a native oxide film or surface contamination as well as variations in material density on the total electron yield (TEY) of Ru and B4C were assessed in the absence of any surface charging effect. The experimental results were analyzed using semi-empirical Monte Carlo simulations and demonstrated that a native oxide film increased the TEY, and that this effect varied with film thickness. These phenomena were explained based on the effect of the backscattered electrons (BSEs) at the interface between Ru and RuO2, as well as the lower potential barrier of RuO2. Deviations in the material density from the theoretical values were attributed to the film deposition procedure based on fitting simulated TEY curves to experimental results. In the case of B4C, the TEY was enhanced by the presence of a 0.8-nm-thick surface contamination film consisting of oxygenated hydrocarbons. The effect of the low potential barrier of the contamination film was found to be significant, as the density of the B4C was much lower than that of the Ru. Comparing the simulation parameters generated in the present work with Joy's database, it was found that the model and the input parameters used in the simulations were sufficiently accurate.

  6. Local states in one-dimensional CDW (charge density wave) materials: Spectral signatures for polarons and bipolarons in MX chains

    Energy Technology Data Exchange (ETDEWEB)

    Swanson, B. I.; Donohoe, R. J.; Worl, L. A.; Bulou, A. D.F.; Arrington, C. A.; Gammel, J. T.; Saxena, A.; Bishop, A. R.

    1990-01-01

    We have undertaken a combined theoretical and experimental effort directed toward the examination of both the ground and defect states in halide-bridged mixed-valence metal linear chains materials as they are tuned within and between broken symmetry phases. Novel low-dimensional highly correlated electronic materials offer a difficult theoretical challenge as we must span from a description of electronic structure on a molecular scale to the meso scale structure that is intrinsic to these solids. Our theoretical effort at Los Alamos combines quantum chemistry, band structure calculations, and many body modeling using Peierls-Hubbard Hamiltonians in order to model ground and local states. The experimental effort combines synthesis and a variety of microscopic structural and spectroscopic probes and macroscopic measurements in an effort to fully characterize both ground and local states as these materials are tuned in the phase boundary regions between broken symmetry states. The present article summarizes some of our recent research using optical spectroscopy to obtain signatures of photoexcited and intrinsic local states and compares these experimental results with Peierls-Hubbard calculations of the optical properties of these materials. Details concerning the theoretical and experimental approaches can be found elsewhere.

  7. Development and characterization of high temperature, high energy density dielectric materials to establish routes towards power electronics capacitive devices

    Science.gov (United States)

    Shay, Dennis P.

    The maximum electrostatic energy density of a capacitor is a function of the relative permittivity (epsilonr) and the square of the dielectric breakdown strength (Eb). Currently, state-of-the art high temperature (>200 °C), SiC-based power electronics utilize CaZrO3-rich NP0/C0G-type capacitors, which have low relative permittivities of epsilonr ˜ 30-40, high breakdown strengths (> 1.0 MV/cm), and are chosen for their minimal change in energy storage with temperature. However, with operating temperatures exceeding the rated temperatures for such capacitors, there is an opportunity to develop new dielectric ceramics having higher energy densities and volumetric efficiencies at high temperatures (>200 °C) by utilizing higher permittivity dielectrics while maintaining high breakdown strengths via doping. The solid solution behavior of was characterized in order to determine the optimal composition for balancing permittivity and dielectric breakdown strength to obtain high energy densities at elevated temperatures. Characterization by X-ray diffraction (XRD) showed Vegard's law behavior across the solid solution with minimal 2nd phases. To determine a Ca(TixZr1-x)O3 composition that will also minimize electronic or band conduction, the optical properties of the Ca(TixZr1-x)O3 solid solution were investigated to identify a composition on the CaTiO3 - rich end of the solid solution with a large band gap. Both ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis) and spectroscopic ellipsometry were utilized to determine the Ca(TixZr1-x)O3 band gaps and optical properties. The resistivity at 250 °C scaled with the band gap energy across the solid solution. Comparing the current-voltage (I--V) behavior at 250 °C for Ca(Tix-yMnyZr0.2)O3 (CTZ + Mn) where x = 0.7, 0.8, 0.9, and y = 0.005, it was found that the Ca(Ti 0.795Mn0.005Zr0.2)O3 composition showed the lowest current density and a decrease in current density of 5 orders of magnitude compared to the un

  8. Density functional description of adsorption in slitlike pores modified with chain molecules: a simple model for pillaredlike materials.

    Science.gov (United States)

    Matusewicz, M; Patrykiejew, A; Sokołowski, S; Pizio, O

    2007-11-07

    We propose a density functional theory to describe adsorption of Lennard-Jones fluid in slitlike pores modified by chain molecules. Specifically, the chains are bonded by their ends to the opposite pore walls, so they can form pillaredlike structure. Two models are studied. In the first model, the nonterminating segments of chains can change their configuration inside the pore upon adsorption of spherical species. In the second model, the chains configuration remains fixed, so that the system is similar to a nonuniform quenched-annealed mixture. We study capillary condensation of fluid species inside such modified pores and compare the results obtained for two models.

  9. Effective atomic numbers and electron densities of some human tissues and dosimetric materials for mean energies of various radiation sources relevant to radiotherapy and medical applications

    Science.gov (United States)

    Kurudirek, Murat

    2014-09-01

    Effective atomic numbers, Zeff, and electron densities, neff, are convenient parameters used to characterise the radiation response of a multi-element material in many technical and medical applications. Accurate values of these physical parameters provide essential data in medical physics. In the present study, the effective atomic numbers and electron densities have been calculated for some human tissues and dosimetric materials such as Adipose Tissue (ICRU-44), Bone Cortical (ICRU-44), Brain Grey/White Matter (ICRU-44), Breast Tissue (ICRU-44), Lung Tissue (ICRU-44), Soft Tissue (ICRU-44), LiF TLD-100H, TLD-100, Water, Borosilicate Glass, PAG (Gel Dosimeter), Fricke (Gel Dosimeter) and OSL (Aluminium Oxide) using mean photon energies, Em, of various radiation sources. The used radiation sources are Pd-103, Tc-99, Ra-226, I-131, Ir-192, Co-60, 30 kVp, 40 kVp, 50 kVp (Intrabeam, Carl Zeiss Meditec) and 6 MV (Mohan-6 MV) sources. The Em values were then used to calculate Zeff and neff of the tissues and dosimetric materials for various radiation sources. Different calculation methods for Zeff such as the direct method, the interpolation method and Auto-Zeff computer program were used and agreements and disagreements between the used methods have been presented and discussed. It has been observed that at higher Em values agreement is quite satisfactory (Dif.<5%) between the adopted methods.

  10. Proceedings of the High Energy Density Materials Contractors Conference Held on 25-28 February 1990 in Long Beach, California

    Science.gov (United States)

    1990-05-01

    4 LUI 0 F- u u < cc z cc U- m< t CD z U - < 4 ) _ u w 282 Stabilization of HEDM Materials S.D. Thompson, R.A. van Opijnen, M.I. Kenney1 , S.L...Soc. (in press). 5. M. Rincon , N. Kirchner and M.T. Bowers, Int. J. Mass Spectrom. lion Proc. 86, 369 (1988). 5. The ground state of carbon ion, C

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

    Directory of Open Access Journals (Sweden)

    Weigelt C.

    2012-08-01

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

  12. Large-scale atomistic simulations of nanostructured materials based on divide-and-conquer density functional theory

    Directory of Open Access Journals (Sweden)

    Vashishta P.

    2011-05-01

    Full Text Available A linear-scaling algorithm based on a divide-and-conquer (DC scheme is designed to perform large-scale molecular-dynamics simulations, in which interatomic forces are computed quantum mechanically in the framework of the density functional theory (DFT. This scheme is applied to the thermite reaction at an Al/Fe2O3 interface. It is found that mass diffusion and reaction rate at the interface are enhanced by a concerted metal-oxygen flip mechanism. Preliminary simulations are carried out for an aluminum particle in water based on the conventional DFT, as a target system for large-scale DC-DFT simulations. A pair of Lewis acid and base sites on the aluminum surface preferentially catalyzes hydrogen production in a low activation-barrier mechanism found in the simulations

  13. Optimal III-nitride HEMTs: from materials and device design to compact model of the 2DEG charge density

    Science.gov (United States)

    Li, Kexin; Rakheja, Shaloo

    2017-02-01

    In this paper, we develop a physically motivated compact model of the charge-voltage (Q-V) characteristics in various III-nitride high-electron mobility transistors (HEMTs) operating under highly non-equilibrium transport conditions, i.e. high drain-source current. By solving the coupled Schrödinger-Poisson equation and incorporating the two-dimensional electrostatics in the channel, we obtain the charge at the top-of-the-barrier for various applied terminal voltages. The Q-V model accounts for cutting off of the negative momenta states from the drain terminal under high drain-source bias and when the transmission in the channel is quasi-ballistic. We specifically focus on AlGaN and AlInN as barrier materials and InGaN and GaN as the channel material in the heterostructure. The Q-V model is verified and calibrated against numerical results using the commercial TCAD simulator Sentaurus from Synopsys for a 20-nm channel length III-nitride HEMT. With 10 fitting parameters, most of which have a physical origin and can easily be obtained from numerical or experimental calibration, the compact Q-V model allows us to study the limits and opportunities of III-nitride technology. We also identify optimal material and geometrical parameters of the device that maximize the carrier concentration in the HEMT channel in order to achieve superior RF performance. Additionally, the compact charge model can be easily integrated in a hierarchical circuit simulator, such as Keysight ADS and CADENCE, to facilitate circuit design and optimization of various technology parameters.

  14. Energy and density analysis of the H2 molecule from the united atom to dissociation: The 3Σg+ and 3Σu+ states

    Science.gov (United States)

    Corongiu, Giorgina; Clementi, Enrico

    2009-11-01

    The first 14 Σ3g+ and the first 15 Σ3u+ states of the H2 molecule are computed with full configuration interaction both from Hartree-Fock molecular orbitals and Heitler-London atomic orbitals within the Born-Oppenheimer approximation, following recent studies for the Σ1g+ and Σ1u+ manifolds [Corongiu and Clementi, J. Chem. Phys. 131, 034301 (2009) and J. Phys. Chem. (in press)]. The basis sets utilized are extended and optimized Slater-type functions and spherical Gaussian functions. The states considered correspond to the configurations (1s1nl1) with n from 1 to 5; the internuclear separations sample the distances from 0.01 to 10 000 bohrs. For the first three Σ3g+ and Σ3u+ states and for the fourth and fifth Σ3g+ states, our computed energies at the equilibrium internuclear separation, when compared to the accurate values by Staszewska and Wolniewicz and by Kołos and Rychlewski, show deviations of about 0.006 kcal/mol, a test on the quality of our computations. Motivation for this work comes not only from obtaining potential energy curves for the high excited states of H2 but also from characterizing the electronic density evolution from the united atom to dissociation to provide a detailed analysis of the energy contributions from selected basis subsets and to quantitatively decompose the state energies into covalent and ionic components. Furthermore, we discuss the origin of the seemingly irregular patterns in potential energy curves in the two manifolds, between 4 and 6-9 bohrs—there are two systems of states: the first, from the united atom to about 4 bohrs, is represented by functions with principal quantum number higher than the one needed at dissociation; this system interacts at around 4 bohrs with the second system, which is represented by functions with principal quantum number corresponding to one of the dissociation products.

  15. Accounting for density reduction and structural loss in standing dead trees: Implications for forest biomass and carbon stock estimates in the United States

    Directory of Open Access Journals (Sweden)

    Domke Grant M

    2011-11-01

    Full Text Available Abstract Background Standing dead trees are one component of forest ecosystem dead wood carbon (C pools, whose national stock is estimated by the U.S. as required by the United Nations Framework Convention on Climate Change. Historically, standing dead tree C has been estimated as a function of live tree growing stock volume in the U.S.'s National Greenhouse Gas Inventory. Initiated in 1998, the USDA Forest Service's Forest Inventory and Analysis program (responsible for compiling the Nation's forest C estimates began consistent nationwide sampling of standing dead trees, which may now supplant previous purely model-based approaches to standing dead biomass and C stock estimation. A substantial hurdle to estimating standing dead tree biomass and C attributes is that traditional estimation procedures are based on merchantability paradigms that may not reflect density reductions or structural loss due to decomposition common in standing dead trees. The goal of this study was to incorporate standing dead tree adjustments into the current estimation procedures and assess how biomass and C stocks change at multiple spatial scales. Results Accounting for decay and structural loss in standing dead trees significantly decreased tree- and plot-level C stock estimates (and subsequent C stocks by decay class and tree component. At a regional scale, incorporating adjustment factors decreased standing dead quaking aspen biomass estimates by almost 50 percent in the Lake States and Douglas-fir estimates by more than 36 percent in the Pacific Northwest. Conclusions Substantial overestimates of standing dead tree biomass and C stocks occur when one does not account for density reductions or structural loss. Forest inventory estimation procedures that are descended from merchantability standards may need to be revised toward a more holistic approach to determining standing dead tree biomass and C attributes (i.e., attributes of tree biomass outside of sawlog

  16. Spectral properties of actinide materials: Charge density self-consistent LDA+Hubbard I method in FP-LAPW basis

    Energy Technology Data Exchange (ETDEWEB)

    Kolorenc, Jindrich [Institute of Physics ASCR, Prague (Czech Republic); University of Hamburg, Hamburg (Germany); Shick, Alexander B. [Institute of Physics ASCR, Prague (Czech Republic); Havela, Ladislav [Charles University, Prague (Czech Republic); Lichtenstein, Alexander I. [University of Hamburg, Hamburg (Germany)

    2010-07-01

    We provide a numerically efficient procedure to perform LDA+Hubbard I calculations including self-consistency over the charge density in the FP-LAPW basis. The method is applied to Pu, Am, and PuAm and PuCe alloys. Our results for valence photoemission spectra (PES) agree with experimental data and with previous LDA+DMFT calculations. Analysis of the J=5/2 and J=7/2 contributions to the f-occupation supports the intermediate-coupling picture of f-states in heavy actinides. The electronic specific heat coefficient is calculated for PuAm and PuCe alloys in reasonable agreement with recent experiments. We show that Pu atoms keep their mixed-valence character in these alloys. Next, we study electronic and spectral properties of Pu-based superconductor PuCoGa{sub 5} and obtain good agreement with experimental PES. Finally, we analyze surface effects. In Pu monolayer, we find substantial modification of PES due to 5f-electron localization consistent with experimental observations.

  17. Energy and Density Analyses of the 1Σu+ States in the H2 Molecule from the United Atom to Dissociation

    Science.gov (United States)

    Corongiu, Giorgina; Clementi, Enrico

    2009-07-01

    The 1Σu+ excited states of the H2 molecule are computed following a recent study by Corongiu and Clementi (J. Chem. Phys. 2009, 131, 034301) on the 1Σg+ states. Full configuration interaction computations both from Hartree-Fock molecular orbitals and Heitler-London atomic orbitals are presented and correlated with a comprehensive analysis. The basis sets utilized are either extended and optimized Slater type functions, STO, or spherical Gaussian functions, GTO. Computations and analyses are presented for states 1 to 14, covering the internuclear distances from 0.01 to 10000 bohr. The accurate data by L. Wolniewicz and collaborators, available for the first six excited states, verify the good quality of our computations. We focus on the characterization of the orbitals in the excited state wave functions, on the electronic density evolution from the united atom to dissociation, on quantitative decomposition of the total energy into covalent and ionic components and on detailed analyses of energy contributions to the total state energy from selected STO subsets. Each manifold has one state, specifically the states 1, 3 and 6, where the second minimum has strong ionic character. State 10 dissociates into the ion pair H+H-.

  18. Energy and density analyses of the 1Sigma(u)+ states in the H2 molecule from the united atom to dissociation.

    Science.gov (United States)

    Corongiu, Giorgina; Clementi, Enrico

    2009-12-31

    The 1Sigma(u)+ excited states of the H2 molecule are computed following a recent study by Corongiu and Clementi (J. Chem. Phys. 2009, 131, 034301) on the 1Sigma(g)+ states. Full configuration interaction computations both from Hartree-Fock molecular orbitals and Heitler-London atomic orbitals are presented and correlated with a comprehensive analysis. The basis sets utilized are either extended and optimized Slater type functions, STO, or spherical Gaussian functions, GTO. Computations and analyses are presented for states 1 to 14, covering the internuclear distances from 0.01 to 10000 bohr. The accurate data by L. Wolniewicz and collaborators, available for the first six excited states, verify the good quality of our computations. We focus on the characterization of the orbitals in the excited state wave functions, on the electronic density evolution from the united atom to dissociation, on quantitative decomposition of the total energy into covalent and ionic components and on detailed analyses of energy contributions to the total state energy from selected STO subsets. Each manifold has one state, specifically the states 1, 3 and 6, where the second minimum has strong ionic character. State 10 dissociates into the ion pair H+H-.

  19. Catalytic Pyrolysis of Low Density Polyethylene Using Cetyltrimethyl Ammonium Encapsulated Monovacant Keggin Units C19H42N4H3(PW11O39 and ZSM-5

    Directory of Open Access Journals (Sweden)

    Madeeha Batool

    2016-01-01

    Full Text Available The effect of the catalysts on the pyrolysis of commercial low density polyethylene (LDPE has been studied in a batch reactor. The thermal catalytic cracking of the LDPE has been done using cetyltrimethyl ammonium encapsulated monovacant keggin units (C19H42N4H3(PW11O39, labeled as CTA-POM and compared with the ZSM-5 catalyst. GC-MS results showed that catalytic cracking of LDPE beads generated oilier fraction over CTA-POM as compared to ZSM-5. Thus, the use of CTA-POM is more significant because it yields more useful fraction. It was also found that the temperature required for the thermal degradation of LDPE was lower when CTA-POM was used as a catalyst while high temperature was required for degradation over ZSM-5 catalyst. Better activity of CTA-POM was due to hydrophobic nature of CTA moiety which helps in catalyst mobility and increases its interaction with hydrocarbons.

  20. Development of a low-adiabat drive for material science experiments on NIF using release and recompression of low density organic foams

    Science.gov (United States)

    Wehrenberg, Christopher; Prisbrey, Shon T.; Park, Hye-Sook; Benedetti, L. Robin; Huntington, Channing; McNaney, James; Smith, Ray; Panas, Cynthia; Cook, Angela; Remington, Bruce; Arsenlis, Tom; Graham, Peter

    2015-11-01

    A series of experiments were performed on NIF to develop a planar, 3-shock, low-adiabat drive for material science experiments. Physics samples (Ta, Pb, etc.) are loaded to 3-4 Mbar while staying well below the melt temperature. X-ray ablation from an indirect drive launches a strong (~ 50 Mbar), decaying shock through a precision fabricated ``reservoir,'' consisting of a CH ablator, followed by layers of Al, CH(18.75%I), ~ 375 mg/cc carbonized resorcinol formaldehyde foam, and a final layer of low density (10-35) mg/cc foam. As the releasing reservoir stagnates on a Ta drive plate, VISAR is used to measures the resulting compression waves. The lowest density reservoir layer is responsible for the leading shock and induces the most entropy during the drive. LLNL has developed a new, low-density foam called JX6 (C20H30) for the purpose of controlling the leading shock. We will describe a series of experiments done on NIF to test the combined release and recompression properties of JX6 and to develop a new, lower-adiabat drive. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344.

  1. [Regeneration processes in bone defects after implantation of composite material of different density of polylactide origin filled with HAP (experimental-morphological study)].

    Science.gov (United States)

    Kulakov, A A; Grigor'ian, A S; Krotova, L I; Popov, V K; Volozhin, A I; Losev, V F

    2009-01-01

    In experimental-morphological study on 6 dogs the dynamics of regenerate formation in ulna and mandible defects after implantation in them composite material of different density (0.46-0.50 and 0.38-0.42 g/cm(3)) of polylactide (PL) origin filled with HAP was followed at the terms of 6 and 9 months. Histologic study and structural determinant distribution analysis in the content of regenerate showed that optimal results according to the bone defect substitution by bone regenerate criterion at 9th month of the experiment were received after composite material from PL and HAP with the density of 0.38-0.42 g/cm(3) implantation. Newly formed trabecular bone tissue was seen in the regenerate and as well as strong tendency for bone matrix maturation. It was confirmed by the appearance of lamellar structures in newly formed bone trabecules situated in peripheral zones of bone defect. In bone mandible defects the substitution process of the implants from PL with HAP by the bone tissue was much slower than in ulna defects.

  2. Beam hardening and smoothing correction effects on performance of micro-ct SkyScan 1173 for imaging low contrast density materials

    Energy Technology Data Exchange (ETDEWEB)

    Sriwayu, Wa Ode [Physics Departement, Haluoleo University Indonesia (Indonesia); Haryanto, Freddy; Khotimah, Siti Nurul; Latief, Fourier Dzar Eljabbar [Physics Departement, ITB Indonesia email : ayoe-fisika@yahoo.com (Indonesia)

    2015-04-16

    We have designed and fabricated phantom mimicking breast cancer composition known as a region that has low contrast density. The used compositions are a microcalcifications, fatty tissues and tumor mass by using Al{sub 2}O{sub 3}, C{sub 27}H{sub 46}O, and hard nylon materials. Besides, phantom also has a part to calculate low cost criteria /CNR (Contrast to Noise Ratio). Uniformity will be measured at water distillation medium located in a part of phantom scale contrast. Phantom will be imaged by using micro ct-sky scan 1173 high energy type, and then also can be quantified CT number to examine SkyScan 1173 performance in imaging low contrast density materials. Evaluation of CT number is done at technique configuration parameter using voltage of 30 kV, exposure 0.160 mAs, and camera resolution 560x560 pixel, the effect of image quality to reconstruction process is evaluated by varying image processing parameters in the form of beam hardening corrections with amount of 25%, 66% and100% with each smoothing level S10,S2 and S7. To obtain the better high quality image, the adjustment of beam hardening correction should be 66% and smoothing level reach maximal value at level 10.

  3. A density functional study on properties of a Cu3Zn material and CO adsorption onto its surfaces

    Science.gov (United States)

    Tang, Qian-Lin; Duan, Xiao-Xuan; Liu, Bei; Wei, An-Qing; Liu, Sheng-Long; Wang, Qi; Liang, Yan-Ping; Ma, Xiao-Hua

    2016-02-01

    Prior experimental and theoretical efforts have provided strong evidence that the formation of α-brass such as Cu3Zn alloys in Cu/ZnO/Al2O3 CO2/CO hydrogenation catalysts enhances dramatically the catalytic activity toward methanol synthesis. In this work, a density functional theory (DFT) slab model has been adopted to get information concerning the bulk and surface properties of DO23-like Cu3Zn and to explore CO molecular adsorption, which will help pave the way to future rationalization of the impact of surface alloying on Cu/ZnO-based catalysis for CO2 and CO hydrogenations. Our calculations imply that the bulk modulus and cohesive energy of the binary solid solution lie between the corresponding ones for the individual components, but only the former quantity equals its composition weighted average. From the DFT-computed surface energies, the stability of Cu3Zn surfaces was predicted to be reinforced in the sequence (1 1 0) electronic structure evaluation reveals that as far as all the alloy surfaces under scrutiny are concerned, a layer of CO brought a decrease, not an increase, in work function for (1 0 1)Zn and (1 1 0)CuZn, though the electrons always flowed from the substrate to the adsorbate. The finding is not trivial at all since it counters the classical rule that an electronegative species raises the work function of the underlying surface. The bonding of CO to the Cu3Zn systems via C-Cu contacts was identified as being primarily covalent rather than ionic. A simple d-band energy model is able to capture the bonding tendency observed.

  4. Changes in forest composition, stem density, and biomass from the settlement era (1800s) to present in the upper Midwestern United States

    Science.gov (United States)

    Goring, Simon; Mladenoff, David J.; Cogbill, Charles; Record, Sydne; Paciorek, Christopher J.; Dietze, Michael C.; Dawson, Andria; Matthes, Jaclyn; McLachlan, Jason S.; Williams, John W.

    2016-01-01

    EuroAmerican land use and its legacies have transformed forest structure and composition across the United States (US). More accurate reconstructions of historical states are critical to understanding the processes governing past, current, and future forest dynamics. Gridded (8x8km) estimates of pre-settlement (1800s) forests from the upper Midwestern US (Minnesota, Wisconsin, and most of Michigan) using 19th Century Public Land Survey (PLS) records provide relative composition, biomass, stem density, and basal area for 26 tree genera. This mapping is more robust than past efforts, using spatially varying correction factors to accommodate sampling design, azimuthal censoring, and biases in tree selection. We compare pre-settlement to modern forests using Forest Inventory and Analysis (FIA) data, with respect to structural changes and the prevalence of lost forests, pre-settlement forests with no current analogue, and novel forests, modern forests with no past analogs. Differences between PLSS and FIA forests are spatially structured as a result of differences in the underlying ecology and land use impacts in the Upper Midwestern United States. Modern biomass is higher than pre-settlement biomass in the northwest (Minnesota and north-eastern Wisconsin, including regions that were historically open savanna), and lower in the east (eastern Wisconsin and Michigan), due to shifts in species composition and, presumably, average stand age. Modern forests are more homogeneous, and ecotonal gradients are more diffuse today than in the past. Novel forest assemblages represent 29% of all FIA cells, while 25% of pre-settlement forests no longer exist in a modern context. Lost forests are centered around the forests of the Tension Zone, particularly in hemlock dominated forests of north-central Wisconsin, and in oak-elm-basswood forests along the forest-prairie boundary in south central Minnesota and eastern Wisconsin. Novel FIA forest assemblages are distributed evenly across

  5. Energy and density analysis of the H2 molecule from the united atom to dissociation: the 3Sigma(g)+ and 3Sigma(u)+ states.

    Science.gov (United States)

    Corongiu, Giorgina; Clementi, Enrico

    2009-11-14

    The first 14 (3)Sigma(g)(+) and the first 15 (3)Sigma(u)(+) states of the H(2) molecule are computed with full configuration interaction both from Hartree-Fock molecular orbitals and Heitler-London atomic orbitals within the Born-Oppenheimer approximation, following recent studies for the (1)Sigma(g)(+) and (1)Sigma(u)(+) manifolds [Corongiu and Clementi, J. Chem. Phys. 131, 034301 (2009) and J. Phys. Chem. (in press)]. The basis sets utilized are extended and optimized Slater-type functions and spherical Gaussian functions. The states considered correspond to the configurations (1s(1)nl(1)) with n from 1 to 5; the internuclear separations sample the distances from 0.01 to 10,000 bohrs. For the first three (3)Sigma(g)(+) and (3)Sigma(u)(+) states and for the fourth and fifth (3)Sigma(g)(+) states, our computed energies at the equilibrium internuclear separation, when compared to the accurate values by Staszewska and Wolniewicz and by Kołos and Rychlewski, show deviations of about 0.006 kcal/mol, a test on the quality of our computations. Motivation for this work comes not only from obtaining potential energy curves for the high excited states of H(2) but also from characterizing the electronic density evolution from the united atom to dissociation to provide a detailed analysis of the energy contributions from selected basis subsets and to quantitatively decompose the state energies into covalent and ionic components. Furthermore, we discuss the origin of the seemingly irregular patterns in potential energy curves in the two manifolds, between 4 and 6-9 bohrs--there are two systems of states: the first, from the united atom to about 4 bohrs, is represented by functions with principal quantum number higher than the one needed at dissociation; this system interacts at around 4 bohrs with the second system, which is represented by functions with principal quantum number corresponding to one of the dissociation products.

  6. Effect of technique and impression material on the vertical misfit of a screw-retained, three-unit implant bridge: An in vitro study

    Directory of Open Access Journals (Sweden)

    Hamidreza Rajati Haghi

    2017-01-01

    Conclusion: Within the limitations of this study, the following conclusions can be drawn: The impression method had no effect on marginal discrepancy of 3-unit screw retained fixed partial dentures. A higher marginal accuracy was obtained using polyether impression material compared to polyvinyl siloxane.

  7. Density functional theory meta-GGA + U study of water incorporation in the metal-organic framework material Cu-BTC

    Science.gov (United States)

    Cockayne, Eric; Nelson, Eric B.

    2015-07-01

    Water absorption in the metal-organic framework (MOF) material Cu-BTC, up to a concentration of 3.5 H2O per Cu ion, is studied via density functional theory at the meta-GGA + U level. The stable arrangements of water molecules show chains of hydrogen-bonded water molecules and a tendency to form closed cages at high concentration. Water clusters are stabilized primarily by a combination of water-water hydrogen bonding and Cu-water oxygen interactions. Stability is further enhanced by van der Waals interactions, electric field enhancement of water-water bonding, and hydrogen bonding of water to framework oxygens. We hypothesize that the tendency to form such stable clusters explains the particularly strong affinity of water to Cu-BTC and related MOFs with exposed metal sites.

  8. Three-dimensional assessment of the effects of high-density embolization material on the absorbed dose in the target for Gamma Knife radiosurgery of arteriovenous malformations.

    Science.gov (United States)

    Watanabe, Yoichi; Sandhu, Divyajot; Warmington, Leighton; Moen, Sean; Tummala, Ramachandra

    2016-12-01

    OBJECTIVE Arteriovenous malformation (AVM) is an intracranial vascular disorder. Gamma Knife radiosurgery (GKRS) is used in conjunction with intraarterial embolization to eradicate the nidus of AVMs. Clinical results indicate that patients with prior embolization tend to gain less benefit from GKRS. The authors hypothesized that this was partly caused by dosimetric deficiency. The actual dose delivered to the target may be smaller than the intended dose because of increased photon attenuation by high-density embolic materials. The authors performed a phantom-based study to quantitatively evaluate the 3D dosimetric effect of embolic material on GKRS. METHODS A 16-cm-diameter and 12-cm-long cylindrical phantom with a 16-cm-diameter hemispherical dome was printed by a 3D printer. The phantom was filled with radiologically tissue-equivalent polymer gel. To simulate AVM treatment with embolization, phantoms contained Onyx 18. The material was injected into an AVM model, which was suspended in the polymer gel. The phantom was attached to a Leksell frame by standard GK fixation method, using aluminum screws, for imaging. The phantom was scanned by a Phillips CT scanner with the standard axial-scanning protocol (120 kV and 1.5-mm slice thickness). CT-based treatment planning was performed with the GammaPlan treatment planning system (version 10.1.1). The plan was created to cover a fictitious AVM target volume near the embolization areas with eleven 8-mm shots and a prescription dose of 20 Gy to 50% isodose level. Dose distributions were computed using both tissue maximum ratio (TMR) 10 and convolution dose-calculation algorithms. These two 3D dose distributions were compared using an in-house program. Additionally, the same analysis method was applied to evaluate the dosimetric effects for 2 patients previously treated by GKRS. RESULTS The phantom-based analyses showed that the mean dose difference between TMR 10 and convolution doses of the AVM target was no larger than

  9. Standard test method for nondestructive assay of special nuclear material in low density scrap and waste by segmented passive gamma-Ray scanning

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method covers the transmission-corrected nondestructive assay (NDA) of gamma-ray emitting special nuclear materials (SNMs), most commonly 235U, 239Pu, and 241Am, in low-density scrap or waste, packaged in cylindrical containers. The method can also be applied to NDA of other gamma-emitting nuclides including fission products. High-resolution gamma-ray spectroscopy is used to detect and measure the nuclides of interest and to measure and correct for gamma-ray attenuation in a series of horizontal segments (collimated gamma detector views) of the container. Corrections are also made for counting losses occasioned by signal processing limitations (1-3). 1.2 There are currently several systems in use or under development for determining the attenuation corrections for NDA of radioisotopic materials (4-8). A related technique, tomographic gamma-ray scanning (TGS), is not included in this test method (9, 10, 11). 1.2.1 This test method will cover two implementations of the Segmented Gamma Scanning ...

  10. 24 CFR 245.417 - Initial submission of materials to HUD: Conversion of residential units to a nonresidential use...

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Initial submission of materials to... housing), the materials specified in paragraphs (a)(1), (a)(2) and (a)(3) of this section and the following additional materials: (1) An estimate of the demand for cooperative housing, including an estimate...

  11. Trends in low-density lipoprotein cholesterol goal achievement in high risk United States adults: longitudinal findings from the 1999-2008 National Health and Nutrition Examination Surveys.

    Directory of Open Access Journals (Sweden)

    Matthew C Tattersall

    Full Text Available BACKGROUND: Previous studies have demonstrated gaps in achievement of low-density lipoprotein-cholesterol (LDL-C goals among U.S. individuals at high cardiovascular disease risk; however, recent studies in selected populations indicate improvements. OBJECTIVE: We sought to define the longitudinal trends in achieving LDL-C goals among high-risk United States adults from 1999-2008. METHODS: We analyzed five sequential population-based cross-sectional National Health and Nutrition Examination Surveys 1999-2008, which included 18,656 participants aged 20-79 years. We calculated rates of LDL-C goal achievement and treatment in the high-risk population. RESULTS: The prevalence of high-risk individuals increased from 13% to 15.5% (p = 0.046. Achievement of LDL-C <100 mg/dL increased from 24% to 50.4% (p<0.0001 in the high-risk population with similar findings in subgroups with (27% to 64.8% p<0.0001 and without (21.8% to 43.7%, p<0.0001 coronary heart disease (CHD. Achievement of LDL-C <70 mg/dL improved from 2.4% to 17% (p<0.0001 in high-risk individuals and subgroups with (3.4% to 21.4%, p<0.0001 and without (1.7% to 14.9%, p<0.0001 CHD. The proportion with LDL-C ≥130 mg/dL and not on lipid medications decreased from 29.4% to 18% (p = 0.0002, with similar findings among CHD (25% to 11.9% p = 0.0013 and non-CHD (35.8% to 20.8% p<0.0001 subgroups. CONCLUSION: The proportions of the U.S. high-risk population achieving LDL-C <100 mg/dL and <70 mg/dL increased over the last decade. With 65% of the CHD subpopulation achieving an LDL-C <100 mg/dL in the most recent survey, U.S. LDL-C goal achievement exceeds previous reports and approximates rates achieved in highly selected patient cohorts.

  12. Evaluation of accuracy of complete-arch multiple-unit abutment-level dental implant impressions using different impression and splinting materials.

    Science.gov (United States)

    Buzayan, Muaiyed; Baig, Mirza Rustum; Yunus, Norsiah

    2013-01-01

    This in vitro study evaluated the accuracy of multiple-unit dental implant casts obtained from splinted or nonsplinted direct impression techniques using various splinting materials by comparing the casts to the reference models. The effect of two different impression materials on the accuracy of the implant casts was also evaluated for abutment-level impressions. A reference model with six internal-connection implant replicas placed in the completely edentulous mandibular arch and connected to multi-base abutments was fabricated from heat-curing acrylic resin. Forty impressions of the reference model were made, 20 each with polyether (PE) and polyvinylsiloxane (PVS) impression materials using the open tray technique. The PE and PVS groups were further subdivided into four subgroups of five each on the bases of splinting type: no splinting, bite registration PE, bite registration addition silicone, or autopolymerizing acrylic resin. The positional accuracy of the implant replica heads was measured on the poured casts using a coordinate measuring machine to assess linear differences in interimplant distances in all three axes. The collected data (linear and three-dimensional [3D] displacement values) were compared with the measurements calculated on the reference resin model and analyzed with nonparametric tests (Kruskal-Wallis and Mann-Whitney). No significant differences were found between the various splinting groups for both PE and PVS impression materials in terms of linear and 3D distortions. However, small but significant differences were found between the two impression materials (PVS, 91 μm; PE, 103 μm) in terms of 3D discrepancies, irrespective of the splinting technique employed. Casts obtained from both impression materials exhibited differences from the reference model. The impression material influenced impression inaccuracy more than the splinting material for multiple-unit abutment-level impressions.

  13. Wind energy in the United States and materials required for the land-based wind turbine industry from 2010 through 2030

    Science.gov (United States)

    Wilburn, David R.

    2011-01-01

    The generation of electricity in the United States from wind-powered turbines is increasing. An understanding of the sources and abundance of raw materials required by the wind turbine industry and the many uses for these materials is necessary to assess the effect of this industry's growth on future demand for selected raw materials relative to the historical demand for these materials. The U.S. Geological Survey developed estimates of future requirements for raw (and some recycled) materials based on the assumption that wind energy will supply 20 percent of the electricity consumed in the United States by 2030. Economic, environmental, political, and technological considerations and trends reported for 2009 were used as a baseline. Estimates for the quantity of materials in typical "current generation" and "next generation" wind turbines were developed. In addition, estimates for the annual and total material requirements were developed based on the growth necessary for wind energy when converted in a wind powerplant to generate 20 percent of the U.S. supply of electricity by 2030. The results of the study suggest that achieving the market goal of 20 percent by 2030 would require an average annual consumption of about 6.8 million metric tons of concrete, 1.5 million metric tons of steel, 310,000 metric tons of cast iron, 40,000 metric tons of copper, and 380 metric tons of the rare-earth element neodymium. With the exception of neodymium, these material requirements represent less than 3 percent of the U.S. apparent consumption for 2008. Recycled material could supply about 3 percent of the total steel required for wind turbine production from 2010 through 2030, 4 percent of the aluminum required, and 3 percent of the copper required. The data suggest that, with the possible exception of rare-earth elements, there should not be a shortage of the principal materials required for electricity generation from wind energy. There may, however, be selective

  14. The StreamCat Dataset: Accumulated Attributes for NHDPlusV2 Catchments (Version 2.1) for the Conterminous United States: Canal Density

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset represents the canal density within individual, local NHDPlusV2 catchments and upstream, contributing watersheds. Attributes of the landscape layer were...

  15. The StreamCat Dataset: Accumulated Attributes for NHDPlusV2 Catchments (Version 2.1) for the Conterminous United States: 2010 US Census Road Density

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset represents the road density within individual, local NHDPlusV2 catchments and upstream, contributing watersheds. Attributes of the landscape layer were...

  16. The StreamCat Dataset: Accumulated Attributes for NHDPlusV2 Catchments (Version 2.1) for the Conterminous United States: Dam Density and Storage Volume

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset represents the dam density and storage volumes within individual, local NHDPlusV2 catchments and upstream, contributing watersheds based on National...

  17. EnviroAtlas - Frequency and Density of Candidate Areas for Ecological Restoration by 12-digit HUC for the Conterminous United States

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset shows the number and density of candidate areas for ecological restoration in each 12-digit HUC. Ecological restoration may become a more...

  18. NOAA Point Shapefile - 100m2 Fish Density for Virgin Passage, United States Virgin Islands, Project NF-10-03-USVI, 2010, WGS84

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data contains densities of fishes detected using mobile fisheries sonar on board the NOAA Ship Nancy Foster. The data were acquired in concert with a multibeam...

  19. NOAA Point Shapefile - 100m2 Fish Density of St. Johns Shelf, United States Virgin Islands, Project NF-10-03-USVI, 2010, WGS84

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data contains densities of fishes detected using mobile fisheries sonar on board the NOAA Ship Nancy Foster. The data were acquired in concert with a multibeam...

  20. Development of innovative teaching materials: clinical pharmacology problem-solving (CPPS) units: comparison with patient-oriented problem-solving units and problem-based learning--a 10-year review.

    Science.gov (United States)

    Lathers, Claire M; Smith, Cedric M

    2002-05-01

    academic centers. Evaluations by faculty and students have been overwhelmingly positive. Requests to use the CPPS units in various clinical pharmacology teaching programs were received from numerous schools within the United States and from abroad. The third teaching clinic in September 1995 included a follow-up focused on the uses of drug information databases in case problem exercises. These examples are presented to demonstrate the variety of educational activities the American College of Clinical Pharmacology is sponsoring to fulfill its strategic initiative dedicated to offer innovative teaching programs and to develop new teaching materials in clinical pharmacology. Collectively, all of the teaching clinics, symposia, and workshop efforts, sponsored by the various academic professional societies alone or together over the past decade, are necessary if new and innovative teaching materials in the field of basic science and in the fields of pharmacology and clinical pharmacology are to be continuously developed to keep pace with the new, rapidly changing developments in medicine to provide the best treatment for patients in the 21st century.

  1. Density functional theory study the effects of oxygen-containing functional groups on oxygen molecules and oxygen atoms adsorbed on carbonaceous materials.

    Science.gov (United States)

    Qi, Xuejun; Song, Wenwu; Shi, Jianwei

    2017-01-01

    Density functional theory was used to study the effects of different types of oxygen-containing functional groups on the adsorption of oxygen molecules and single active oxygen atoms on carbonaceous materials. During gasification or combustion reactions of carbonaceous materials, oxygen-containing functional groups such as hydroxyl(-OH), carbonyl(-CO), quinone(-O), and carboxyl(-COOH) are often present on the edge of graphite and can affect graphite's chemical properties. When oxygen-containing functional groups appear on a graphite surface, the oxygen molecules are strongly adsorbed onto the surface to form a four-member ring structure. At the same time, the O-O bond is greatly weakened and easily broken. The adsorption energy value indicates that the adsorption of oxygen molecules changes from physisorption to chemisorption for oxygen-containing functional groups on the edge of a graphite surface. In addition, our results indicate that the adsorption energy depends on the type of oxygen-containing functional group. When a single active oxygen atom is adsorbed on the bridge site of graphite, it gives rise to a stable epoxy structure. Epoxy can cause deformation of the graphite lattice due to the transition of graphite from sp2 to sp3 after the addition of an oxygen atom. For quinone group on the edge of graphite, oxygen atoms react with carbon atoms to form the precursor of CO2. Similarly, the single active oxygen atoms of carbonyl groups can interact with edge carbon atoms to form the precursor of CO2. The results show that oxygen-containing functional groups on graphite surfaces enhance the activity of graphite, which promotes adsorption on the graphite surface.

  2. Computing mammographic density from a multiple regression model constructed with image-acquisition parameters from a full-field digital mammographic unit

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Lee-Jane W [Department of Preventive Medicine and Community Health, University of Texas Medical Branch, Galveston, TX 77555-1109 (United States); Nishino, Thomas K [Department of Radiology, University of Texas Medical Branch, Galveston, TX 77555-0709 (United States); Khamapirad, Tuenchit [Department of Radiology, University of Texas Medical Branch, Galveston, TX 77555-0709 (United States); Grady, James J [Department of Preventive Medicine and Community Health, University of Texas Medical Branch, Galveston, TX 77555-1109 (United States); Jr, Morton H Leonard [Department of Radiology, University of Texas Medical Branch, Galveston, TX 77555-0709 (United States); Brunder, Donald G [Department of Academic Computing/Academic Resources, University of Texas Medical Branch, Galveston, TX 77555-1035 (United States)

    2007-08-21

    Breast density (the percentage of fibroglandular tissue in the breast) has been suggested to be a useful surrogate marker for breast cancer risk. It is conventionally measured using screen-film mammographic images by a labor-intensive histogram segmentation method (HSM). We have adapted and modified the HSM for measuring breast density from raw digital mammograms acquired by full-field digital mammography. Multiple regression model analyses showed that many of the instrument parameters for acquiring the screening mammograms (e.g. breast compression thickness, radiological thickness, radiation dose, compression force, etc) and image pixel intensity statistics of the imaged breasts were strong predictors of the observed threshold values (model R{sup 2} = 0.93) and %-density (R{sup 2} = 0.84). The intra-class correlation coefficient of the %-density for duplicate images was estimated to be 0.80, using the regression model-derived threshold values, and 0.94 if estimated directly from the parameter estimates of the %-density prediction regression model. Therefore, with additional research, these mathematical models could be used to compute breast density objectively, automatically bypassing the HSM step, and could greatly facilitate breast cancer research studies.

  3. Computing mammographic density from a multiple regression model constructed with image-acquisition parameters from a full-field digital mammographic unit

    Science.gov (United States)

    Lu, Lee-Jane W.; Nishino, Thomas K.; Khamapirad, Tuenchit; Grady, James J.; Leonard, Morton H., Jr.; Brunder, Donald G.

    2007-08-01

    Breast density (the percentage of fibroglandular tissue in the breast) has been suggested to be a useful surrogate marker for breast cancer risk. It is conventionally measured using screen-film mammographic images by a labor-intensive histogram segmentation method (HSM). We have adapted and modified the HSM for measuring breast density from raw digital mammograms acquired by full-field digital mammography. Multiple regression model analyses showed that many of the instrument parameters for acquiring the screening mammograms (e.g. breast compression thickness, radiological thickness, radiation dose, compression force, etc) and image pixel intensity statistics of the imaged breasts were strong predictors of the observed threshold values (model R2 = 0.93) and %-density (R2 = 0.84). The intra-class correlation coefficient of the %-density for duplicate images was estimated to be 0.80, using the regression model-derived threshold values, and 0.94 if estimated directly from the parameter estimates of the %-density prediction regression model. Therefore, with additional research, these mathematical models could be used to compute breast density objectively, automatically bypassing the HSM step, and could greatly facilitate breast cancer research studies.

  4. Variation in chlorophyll content per unit leaf area in spring wheat and implications for selection in segregating material.

    Directory of Open Access Journals (Sweden)

    John Hamblin

    Full Text Available Reduced levels of leaf chlorophyll content per unit leaf area in crops may be of advantage in the search for higher yields. Possible reasons include better light distribution in the crop canopy and less photochemical damage to leaves absorbing more light energy than required for maximum photosynthesis. Reduced chlorophyll may also reduce the heat load at the top of canopy, reducing water requirements to cool leaves. Chloroplasts are nutrient rich and reducing their number may increase available nutrients for growth and development. To determine whether this hypothesis has any validity in spring wheat requires an understanding of genotypic differences in leaf chlorophyll content per unit area in diverse germplasm. This was measured with a SPAD 502 as SPAD units. The study was conducted in series of environments involving up to 28 genotypes, mainly spring wheat. In general, substantial and repeatable genotypic variation was observed. Consistent SPAD readings were recorded for different sampling positions on leaves, between different leaves on single plant, between different plants of the same genotype, and between different genotypes grown in the same or different environments. Plant nutrition affected SPAD units in nutrient poor environments. Wheat genotypes DBW 10 and Transfer were identified as having consistent and contrasting high and low average SPAD readings of 52 and 32 units, respectively, and a methodology to allow selection in segregating populations has been developed.

  5. The StreamCat Dataset: Accumulated Attributes for NHDPlusV2(Version 2.1) Catchments Riparian Buffer for the Conterminous United States: 2010 US Census Road Density

    Science.gov (United States)

    This dataset represents the road density within individual, local NHDPlusV2 catchments and upstream, contributing watersheds riparian buffers. Attributes of the landscape layer were calculated for every local NHDPlusV2 catchment and accumulated to provide watershed-level metrics. (See Supplementary Info for Glossary of Terms) This data set is derived from TIGER/Line Files of roads in the conterminous United States. Road density describes how many kilometers of road exist in a square kilometer. A raster was produced using the ArcGIS Line Density Tool to form the landscape layer for analysis. (see Data Sources for links to NHDPlusV2 data and Census Data) The (kilometer of road/square kilometer) was summarized by local catchment and by watershed to produce local catchment-level and watershed-level metrics as a continuous data type (see Data Structure and Attribute Information for a description).

  6. Technological and material related challenges for large area, high aspect-ratio, near teradot/inch2 areal density and three-dimensional structuring of polyaniline.

    Science.gov (United States)

    Jedrasik, Piotr; Vlad, Alexandru; Södervall, Ulf

    2011-10-01

    In this manuscript we report on a newly developed technology for the nanoscale processing of the conducting polyaniline (PANI) with an unprecedented areal patterning order and density control exceeding 0.25 teradot/inch2. High resolution electron beam lithography was used to generate ordered 2D and 3D templates. A novel type of resist and dose-modulated 3D-electron beam lithography (RDM-3D-EBL), extensively exploiting the intrinsic properties of resist-electron beam interaction is detailed. Surface initiated and template confined aniline polymerization, through catalytic activity of metallic platinum, was then exploited to provide a genuine method for controlled nanoscale processing of polyaniline, a prototypical conjugated polymer that definitively settled the concept of synthetic metals. Using nanoscale polymerization reactors, ultimate resolution patterning and processing control of single polyaniline nanostructures was feasible. Aspects of the nanoscale polyaniline growth mechanism are discussed and the highly controllable, sub-picogram scale fabrication is emphasized. Near teradot/inch2 pattern transfer technology, complex 3D structuring and physico-chemical functionalization of polyaniline can be subsequently harnessed to build a large variety of architectures with potential for emerging optoelectronic technologies. The method is scalable, can be applied on virtually any type of flexible or rigid substrates and provides a generic approach for nanopatterning surfaces with functional polymers. Technological and material related fabrication challenges are detailed and discussed.

  7. Benchmarking Density Functional Theory Based Methods To Model NiOOH Material Properties: Hubbard and van der Waals Corrections vs Hybrid Functionals.

    Science.gov (United States)

    Zaffran, Jeremie; Caspary Toroker, Maytal

    2016-08-09

    NiOOH has recently been used to catalyze water oxidation by way of electrochemical water splitting. Few experimental data are available to rationalize the successful catalytic capability of NiOOH. Thus, theory has a distinctive role for studying its properties. However, the unique layered structure of NiOOH is associated with the presence of essential dispersion forces within the lattice. Hence, the choice of an appropriate exchange-correlation functional within Density Functional Theory (DFT) is not straightforward. In this work, we will show that standard DFT is sufficient to evaluate the geometry, but DFT+U and hybrid functionals are required to calculate the oxidation states. Notably, the benefit of DFT with van der Waals correction is marginal. Furthermore, only hybrid functionals succeed in opening a bandgap, and such methods are necessary to study NiOOH electronic structure. In this work, we expect to give guidelines to theoreticians dealing with this material and to present a rational approach in the choice of the DFT method of calculation.

  8. Resistance of different materials used in sewers systems:Polyvinyl chloride (PVC, polypropylene (PP and High density polyethylene (HDPE, to sulfuric acid and sodium sulfate attack.

    Directory of Open Access Journals (Sweden)

    LASFAR Sara

    2014-02-01

    Full Text Available The behaviour of PVC, PP and HDPE used in sewer systems exposed to acid and sulfate solutions was investigated at 25°C and 40°C. Gravimetric characterization proves that PVC has a fickian behavior. It shows also, that PP has a non-fickian behavior, characterized by a rapid acceleration of water absorption, and the HDPE has a fickian behavior at 25°C, while it has a non-fickian behavior at 40°C, characterized by a weight loss after a certain aging period. The prolongation of the time of exposure to sulfuric acid solution leads to a progressive increase in tensile strength followed by a slight decrease at 40°C. The unaged samples of all materials have a much lower tensile strength than those of the aged samples, and a drop in elongation at break could be observed. These results can be explained by the increase of crystallinity, followed by the increase of crosslinking density due to the diffusion of the solvent and the effect of the temperature as the exposure time increases. These results prove that there is a correlation between the diffusion of the solvent as well as the increased exposure time and temperature on the mechanical properties of polymer.

  9. On density forecast evaluation

    NARCIS (Netherlands)

    Diks, C.

    2008-01-01

    Traditionally, probability integral transforms (PITs) have been popular means for evaluating density forecasts. For an ideal density forecast, the PITs should be uniformly distributed on the unit interval and independent. However, this is only a necessary condition, and not a sufficient one, as

  10. A Meso-Scale Unit-Cell Based Material Model for the Single-Ply Flexible-Fabric Armor

    Science.gov (United States)

    2009-01-01

    next implemented in the material user subrou- tine, VUMAT , of the commercial finite element program ABAQUS/ Explicit [24]. This subroutine is compiled... VUMAT Material User Subrou- tine at each time increment at each integration point of each element can be summarized as follows: (a) The corresponding...values of the mate- rial state variables at the end of the time increment are determined within the VUMAT and returned to the ABA- QUS/Explicit finite

  11. Unit with Fluidized Bed for Gas-Vapor Activation of Different Carbonaceous Materials for Various Purposes: Design, Computation, Implementation

    Science.gov (United States)

    Strativnov, Eugene

    2017-02-01

    We propose the technology of obtaining the promising material with wide specter of application-activated nanostructured carbon. In terms of technical indicators, it will stand next to the materials produced by complex regulations with the use of costly chemical operations. It can be used for the following needs: as a sorbent for hemosorption and enterosorption, for creation of the newest source of electric current (lithium and zinc air batteries, supercapacitors), and for processes of short-cycle adsorption gas separation.

  12. A Method to Formulate the Unit Cell for Density Functional Theory (DFT) Calculations of the Electronic Band Structure of Heterostructures of Two-dimensional Nanosheets

    Science.gov (United States)

    2015-04-01

    distribution is unlimited. i CONTENTS Page Introduction 1 Two-dimensional Material Geometry and Analogs with Close-packed Systems 1 Matching...distribution is unlimited. 1 INTRODUCTION Two-dimensional (2D) material heterostructures offer novel and compelling electronic and optical...methods have undoubtedly been created for matching lattice constants of dissimilar nanomaterials , very few are actually covered explicitly in literature

  13. A survey of power density of clinical curing-light units used in Changchun%长春市口腔临床应用光固化灯的调查

    Institute of Scientific and Technical Information of China (English)

    郝新青; 罗梦; 冷鑫; 朱松

    2011-01-01

    目的调查长春市临床应用光固化灯的功率密度及其相关信息,为临床医师正确维护使用光固化灯提供参考。方法调查对象为长春市口腔专科医院、综合医院口腔科、民营诊所,采用简单随机抽样的方法,共检测270盏光固化灯的功率密度及相关信息,包括光固化灯的品牌、类型、使用年限、光导头数目及类型,光导头玷污、破损情况,使用频率,装置的检测及维修情况,灯数目/牙椅数。结果270盏光固化灯中,卤光灯174盏,发光二极管灯96盏,检测功率密度变化范围在0~1702 mW/cm2,平均功率密度为413.2 mW/cm2,73盏灯小于200 mW/cm2,不能充分聚合光固化复合树脂。光固化灯的平均使用年限为4.7年。大多数医师未检测过光固化灯的功率密度,84%(227/270)的光导头表面有树脂的玷污和破损。结论 长春市大部分光固化灯为卤光灯,部分灯老化明显,需要更新,大多数医师没有注意光固化灯需要定期检测和维修。%Objectives To investigate the power density and other relevant data of clinical curinglight units used in Changchun, and to provide practice recommendations to clinical dentists about maintaining of cuing-light units. Methods Stomatology hospitals, departments of stomatology in general hospitals, and private dental offices in Changchun were randomly selected to participate in the Survey. The investigation analyzed 270 curing-light units. The following data of curing-light units were gathered: brand, type, operation ages, numbers and types of light guide, resin build-ups on light guides, damages of light guides, use frequency, monitor and maintenance of curing lights, and unit numbers/chair nunbers. Results There were 174 QTH and 96 LED units. The distribution of power density was from 0 to 1702 mW/cm2. The mean power density was 413. 2 mW/cm2. The power densities of 73 lights were less than 200 mW/cm2 and could not

  14. Substantiation of the Structural-Layout Scheme of the Mirror-Space-Antenna Reflector with a High Shape Stability and a Low Density per Unit Length

    Science.gov (United States)

    Reznik, S. V.; Prosuntsov, P. V.; Azarov, A. V.

    2015-05-01

    Problems of designing space-antenna reflectors from composite materials for promising telecommunication satellites are considered. Selection of designs is based on the numerical modeling of heat-transfer and mechanics processes corresponding to orbital-flight conditions.

  15. 放射性物位计在连续重整装置的应用%Application of Radioactive Material Level Meter in Continuous Reforming Unit

    Institute of Scientific and Technical Information of China (English)

    杨霄

    2015-01-01

    Catalyst regeneration system is the core part of reaction and regeneration of continuous reforming unit. To provide reliable parameters for control system, the catalyst should be accurately detected in the process of catalyst regeneration and recycling. Radioactive material level meter is an instrument which can accurately detect the catalyst material level. This paper introduces the radioactive material level meter's working principle, configu-rations and protection matters, and meanwhile, introduces the setting and calibration of the meter in continuous re-forming unit with the domestic continuous reforming process.%催化剂再生系统是连续重整装置反再部分的核心环节。在催化剂再生和循环的过程中需要准确检测催化剂的物位,为控制系统提供可靠参数。放射性物位计就是一种能准确检测设备中催化剂物位的仪表。本文介绍了放射性物位计的工作原理、配置方法和防护事项。同时,结合国产连续重整工艺,介绍了放射性物位计在连续重整中的设置和标定。

  16. 77 FR 26317 - Exemption of Material for Proposed Disposal Procedures for the Humboldt Bay Power Plant, Unit 3...

    Science.gov (United States)

    2012-05-03

    ... meters) of hazardous waste, soil, and debris containing low-activity radioactive debris generated during... disposal zone). The engineered features include an engineered cover, liners and leachate monitoring systems.... Need for Proposed Action The subject waste material consists of hazardous waste, soil, and...

  17. National inventories of down and dead woody material forest carbon stocks in the United States: Challenges and opportunities

    Science.gov (United States)

    C.W. Woodall; L.S. Heath; J.E. Smith

    2008-01-01

    Concerns over the effect of greenhouse gases and consequent international agreements and regional/national programs have spurred the need for comprehensive assessments of forest ecosystem carbon stocks. Down and dead woody (DDW) materials are a substantial component of forest carbon stocks; however, few surveys of DDW carbon stocks have been conducted at national-...

  18. Fungicides affect the production of extracellular mucilaginous material (ECMM) and the peripheral growth unit (PGU) in two wood-rotting basidiomycetes.

    Science.gov (United States)

    Vesentini, Damiano; Dickinson, David J; Murphy, Richard J

    2006-10-01

    This study shows the effect of two fungicides on the production of extracellular mucilaginous material (ECMM) in two wood-rotting basidiomycetes and identifies a mechanism that might be responsible for the variation observed. Increasing concentrations of the fungicides copper sulphate (CuSO4) and cyproconazole in the growth medium increased the proportion of ECMM in the biomass of Trametes versicolor and Gloeophyllum trabeum. These fungicides also caused a reduction in the length of the peripheral growth unit (PGU) of the mycelia leading to a more highly branched morphology and a larger number of hyphal tips, the sites for active secretion of ECMM, per unit length of mycelium. It is postulated that both in T. versicolor and G. trabeum this change in growth leads to the increases observed in the proportion of ECMM in the total biomass. The implications of these results are discussed with a view to a potential protective role of ECMM against stress and toxic environments.

  19. Some molecular/crystalline factors that affect the sensitivities of energetic materials: molecular surface electrostatic potentials, lattice free space and maximum heat of detonation per unit volume.

    Science.gov (United States)

    Politzer, Peter; Murray, Jane S

    2015-02-01

    We discuss three molecular/crystalline properties that we believe to be among the factors that influence the impact/shock sensitivities of energetic materials (i.e., their vulnerabilities to unintended detonation due to impact or shock). These properties are (a) the anomalously strong positive electrostatic potentials in the central regions of their molecular surfaces, (b) the free space per molecule in their crystal lattices, and (c) their maximum heats of detonation per unit volume. Overall, sensitivity tends to become greater as these properties increase; however these are general trends, not correlations. Nitramines are exceptions in that their sensitivities show little or no variation with free space in the lattice and heat of detonation per unit volume. We outline some of the events involved in detonation initiation and show how the three properties are related to different ones of these events.

  20. Material Use in the United States - Selected Case Studies for Cadmium, Cobalt, Lithium, and Nickel in Rechargeable Batteries

    Science.gov (United States)

    Wilburn, David R.

    2008-01-01

    This report examines the changes that have taken place in the consumer electronic product sector as they relate to (1) the use of cadmium, cobalt, lithium, and nickel contained in batteries that power camcorders, cameras, cell phones, and portable (laptop) computers and (2) the use of nickel in vehicle batteries for the period 1996 through 2005 and discusses forecasted changes in their use patterns through 2010. Market penetration, material substitution, and technological improvements among nickel-cadmium (NiCd), nickel-metal-hydride (NiMH), and lithium-ion (Li-ion) rechargeable batteries are assessed. Consequences of these changes in light of material consumption factors related to disposal, environmental effects, retail price, and serviceability are analyzed in a series of short case studies.

  1. Unit with Fluidized Bed for Gas-Vapor Activation of Different Carbonaceous Materials for Various Purposes: Design, Computation, Implementation.

    Science.gov (United States)

    Strativnov, Eugene

    2017-12-01

    We propose the technology of obtaining the promising material with wide specter of application-activated nanostructured carbon. In terms of technical indicators, it will stand next to the materials produced by complex regulations with the use of costly chemical operations. It can be used for the following needs: as a sorbent for hemosorption and enterosorption, for creation of the newest source of electric current (lithium and zinc air batteries, supercapacitors), and for processes of short-cycle adsorption gas separation.In this study, the author gives recommendations concerning the design of the apparatus with fluidized bed and examples of calculation of specific devices. The whole given information can be used as guidelines for the design of energy effective aggregates. Calculation and design of the reactor were carried out using modern software complexes (ANSYS and SolidWorks).

  2. Using Defects in Materials to Store Energy: a Theoretical Study

    Science.gov (United States)

    Lu, I.-Te; Bernardi, Marco

    We study the energy stored by defects in materials using density functional theory (DFT) calculations. Leveraging experimental data to estimate the energy density of defects, expressed as the defect formation energy per unit volume (units of MJ/L) or weight (units of MJ/kg), we identify candidates for high energy density storage, including tungsten, diamond, graphite, silicon, and graphene. DFT calculations are applied to these materials to study the formation energy of vacancies, interstitials, and Frenkel pairs. Our results indicate that the energy density stored by defects in these materials, with experimentally accessible non-equilibrium defect concentrations, can be higher than that of common energy storage technologies such as lithium batteries and supercapacitors. We discuss storage of solar energy and electrical energy (through ion bombardment) using defects.

  3. Synthesis, characterization, and properties of peroxo-based oxygen-rich compounds for potential use as greener high energy density materials

    Science.gov (United States)

    Gamage, Nipuni-Dhanesha Horadugoda

    One main aspect of high energy density material (HEDM) design is to obtain greener alternatives for HEDMs that produce toxic byproducts. Primary explosives lead azide, lead styphnate, and mercury fulminate contain heavy metals that cause heavy metal poisoning. Leaching of the widely used tertiary explosive NH4ClO4 into groundwater has resulted in human exposure to ClO4-- ions, which cause disruptions of thyroid related metabolic pathways and even thyroid cancer. Many research efforts to find replacements have gained little success. Thus, there is a need for greener HEDMs. Peroxo-based oxygen-rich compounds are proposed as a potential new class of greener HEDMs due to the evolution of CO2 and/or CO, H2O, and O 2 as the main decomposition products. Currently, triacetone triperoxide (TATP), diacetone diperoxide (DADP), hexamethylene triperoxide diamine (HMTD), and methyl ethyl ketone peroxide (MEKP) are the only well-studied highly energetic peroxides. However, due to their high impact and friction sensitivities, low thermal stabilities, and low detonation velocities they have not found any civil or military HEDM applications. In this dissertation research, we have synthesized and fully characterized four categories of peroxo-based compounds: tert-butyl peroxides, tert-butyl peroxy esters, hydroperoxides, and peroxy acids to perform a systematic study of their sensitivities and the energetic properties for potential use as greener HEDMs. tert-Butyl peroxides were not sensitive to impact, friction, or electrostatic spark. Hence, tert-butyl peroxides can be described as fairly safe peroxo-based compounds to handle. tert-Butyl peroxy esters were all surprisingly energetic (4896--6003 m/s), despite the low oxygen and nitrogen contents. Aromatic tert -butyl peroxy esters were much lower in impact and friction sensitivities with respect to the known peroxo-based explosives. These are among the first low sensitivity peroxo-based compounds that can be categorized as secondary

  4. Influence of Curing Units and Indirect Restorative Materials on the Hardness of Two Dual-curing Resin Cements Evaluated by the Nanoindentation Test.

    Science.gov (United States)

    Kuguimiya, Rosiane Noqueira; Rode, Kátia Martins; Carneiro, Paula Mendes Acatauassú; Aranha, Ana Cecilia Corrêa; Turbino, Miriam Lacalle

    2015-06-01

    To evaluate the hardness of a dual-curing self-adhesive resin cement (RelyX U200) and a conventional dual-curing resin cement (RelyX ARC) cured with different light curing units of different wavelengths (Elipar Freelight 2 LED [430 to 480 nm, conventional], Bluephase LED [380 to 515 nm, polywave], AccuCure 3000 Laser [488 nm]) by means of the nanoindentation test. Bovine incisors were cleaned and then sectioned at the cementoenamel junction to remove the crown. After embedding in acrylic, dentin surfaces of the specimens were exposed and ground flat to standardize the surfaces. To simulate clinically placing indirect restorations, ceramic (IPS e.maxPress/Ivoclar Vivadent) or indirect composite resin (SR Adoro/Ivoclar Vivadent) slabs were cemented on dentin surfaces. The specimens were sectioned longitudinally at low speed under constant irrigation and then polished. In the positive control group, the cement was light cured without the interposition of indirect restorative material; in the negative control group, after the indirect restorative material was cemented, no light curing was performed, allowing only chemical polymerization of the cement. All specimens were stored in distilled water at 37°C for 7 days. Nanoindentadion hardness of the cement layer was measured under a 100-mN load. Data were statistically analyzed using ANOVA and Tukey's test (p < 0.05). Although the self-adhesive cement is technically simple, conventional cement showed the best polymerization performance. The polywave LED technology did not differ significantly from other light-curing units. The hardness of the resin cements evaluated was negatively influenced by the interposition of an indirect restorative material; only the LEDs were able to maintain the same degree of cement polymerization when an indirect restorative material was used. The photoactivation step is required during the cementation of indirect restorations to ensure adequate polymerization of dual-curing resin cements.

  5. It`s not always quantity that counts. The apparent density of insulating material made of mineral wool may be a misleading quality criterion; Masse muss nicht Klasse sein. Warum die Rohdichte von Mineralwolle-Daemmstoffen ein irrefuehrendes Qualitaetsmerkmal ist

    Energy Technology Data Exchange (ETDEWEB)

    Royar, J.

    1995-10-01

    The apparent density of insulating material made of mineral wool is a popular quality criterion that can be assessed easily but does not allow one to evaluate materials reliably. It is not the only characteristic property of such materials and it should always be used in combination with other parameters. Requirements should be based on the relevant material data, i.e. on the thermal conductivity, behavior in fire, dynamic stiffness, sound absorption properties, and mechanical strength of insulating material made of mineral wool. (orig./HW) [Deutsch] Die Rohdichte von Mineralwolle-Daemmstoffen ist zwar eine leicht feststellbare Groesse und erfreut sich grosser Beliebtheit bei der vermeintlich sicheren Beurteilung der Qualitaet. Sie ist jedoch allein niemals und nur im Verbund mit anderen Materialparametern eine kennzeichnende Eigenschaft von Mineralwolle-Daemmstoffen. Bei der Formulierung von Anforderungen sollte man sich demnach auf die relevanten Materialdaten von MW-Daemmstoffen beschraenken: Waermeleitfaehigkeit, Brandverhalten, dynamische Steifigkeit, Schallabsorptionsvermoegen, mechanische Festigkeit. (orig./HW)

  6. APPLICATION OF SPYRO SOFTWARE ON CRUDE MATERIAL OPTIMIZATION IN ETHYLENE UNIT%SPYRO 软件在乙烯原料优化中的应用

    Institute of Scientific and Technical Information of China (English)

    高辉

    2014-01-01

    Final products distribution of Qilu ethylene unit was obtained and the optimiza-tion model on the crude material was built by simulation calculation on analysis data of each crude material combining SPYRO software and prices of crude material and product .Input -output benefit model was built combing with corresponding price system .Adjustment direction on the crude material and process conditions was determined by the calculation and comparison on the double models , which realized value maximization of the cracking products .%将SPYRO软件与原料和产品价格相结合,通过软件对齐鲁乙烯装置各种原料的分析数据进行模拟计算后得到最终产品分布结果,建立原料优化模型;同时结合相应价格体系,建立投入产出效益模型。通过两套模型的计算对比,确定原料和工艺条件的调整方向,实现裂解产物价值最大化。

  7. Benthic Foraminiferal Mg/Ca and Sr/Ca Presented Under Varying Population Densities on the Southeastern United States Continental Shelf

    Science.gov (United States)

    Blanks, J. K.; Hintz, C. J.; Chandler, G. T.; McCorkle, D. C.; Bernhard, J. M.; Shaw, T. J.; Etson, K. M.

    2006-12-01

    Unraveling the inherent variabilities in benthic foraminiferal Mg/Ca and other trace elements will help produce a more refined temperature proxy for benthic foraminiferal calcification temperature. To date, proxy signature variability in field samples has been attributed to microhabitat and poorly understood vital effects. Vital effects such as food supply, calcification rate, metabolic rate, may influence microhabitat chemistry or foraminiferal shell chemistry, but are difficult to measure. However, easily measurable benthic population densities and abundances are likely to be driven by food supply, and may also be controlled by foraminiferal calcification or metabolic rates. Mg/Ca and Sr/Ca from live core-top benthic foraminfera were investigated to test whether vital effect factors, as reflected by faunal abundance and diversity, influence foraminiferal element/calcium ratios. Foraminiferal element/calcium ratios are presented along with corresponding abundances and species diversities of cores collected in 2001, 2005, and 2006 from the shallow-slope environ of the Charleston Bump (31° 55'N, 79° 11'W; ~220m water depth; temp range: 9.4-11.2° C; calcite saturation state: 2.29- 2.73). Overall total foraminiferal population densities increased by 6 fold in the more recent years (2001, n=350, 6.1 individuals/cm3; 2005, n>2300, 40 individuals/cm3; 2006, n>1900, 33.6 individuals/cm3). If a correlation exists between benthic foraminiferal population densities and element/calcium ratios, then this may suggest that biological processes can affect foraminiferal element/calcium shell chemistry. Funded by NSF OCE9911654, OCE0351029, and OCE 0437366.

  8. Factors influencing densities of non-indigenous species in the ballast water of ships arriving at ports in Puget Sound, Washington, United States

    Science.gov (United States)

    Cordell, J.R.; Lawrence, D.J.; Ferm, N.C.; Tear, L.M.; Smith, S.S.; Herwig, R.P.

    2009-01-01

    Oceanographic characteristics and the presence of international shipping in Puget Sound, Washington, USA contribute to its vulnerability to non-indigenous species (NIS) invasions. To evaluate NIS arriving in ballast water, zooplankton was sampled in 380 ballast tanks of ships after they entered Puget Sound. Taxa were classified into a higher risk group of coastal organisms (including known NIS), and a lower risk group of largely oceanic species. Most ships reported conducting mid-ocean ballast water exchange (BWE). However, despite state regulations requiring BWE, and apparent compliance by ship operators, most sampled tanks from both transpacific and coastal routes had coastal zooplankton densities exceeding internationally proposed discharge standards. BWE efficiency models and controlled before-and-after BWE experiments indicate that BWE consistently removes most coastal zooplankton. However, this study found that although the empty-refill method of BWE significantly reduced coastal plankton compared with un-exchanged tanks, the flow-through method did not, and in either case remaining coastal plankton densities presented appreciable risks of introducing NIS. Densities of high risk taxa were consistently and significantly higher from US domestic trips dominated by tank ships carrying ballast water from California, and lower in samples from trans-Pacific trips dominated by container ships and bulk carriers with ballast from Asia. These findings are probably a result of the dense and diverse NIS assemblages present in California and other US west coast estuaries and the comparatively short transit times between them and Puget Sound. While it appears that BWE can effectively replace NIS with less risky ocean species, new reporting, verification, and operational procedures may be necessary to enhance BWE efficacy. In the long-term, the introduction of ballast water treatment technologies may be required to significantly reduce the discharge of risky organisms from

  9. c(4 × 2) and related structural units on the SrTiO3(001) surface: scanning tunneling microscopy, density functional theory, and atomic structure.

    Science.gov (United States)

    Becerra-Toledo, A E; Marshall, M S J; Castell, M R; Marks, L D

    2012-06-07

    Density functional theory is used to simulate high-bias, constant-current scanning tunneling micrographs for direct comparison with experimental images. Coupled to previous spectroscopic data, these simulations are used to determine the atomic structure of Ti-rich nanostructures on strontium titanate (001) surfaces. These nanostructures have three consecutive TiO(x) surface layers and exploit the distinctive structural motif of the c(4 × 2) reconstruction as their main building block. A structural model of a characteristic triline defect is also proposed.

  10. Small D-π-A systems with o-phenylene-bridged accepting units as active materials for organic photovoltaics.

    Science.gov (United States)

    Leliège, Antoine; Grolleau, Jérémie; Allain, Magali; Blanchard, Philippe; Demeter, Dora; Rousseau, Théodulf; Roncali, Jean

    2013-07-22

    Donor-acceptor (D-π-A) systems that combine triarylamine donor blocks and dicyanovinyl (DCV) acceptor groups have been synthesized. Starting from the triphenylamine (TPA)-thiophene-DCV compound (1) as a reference system, various synthetic approaches have been developed for controlling the light-harvesting properties and energy levels of the frontier orbitals in this molecule. Thus, the introduction of methoxy groups onto TPA, the replacement of one phenyl ring of TPA by a thiophene ring, or the extension of the π-conjugating spacer group lead to the modulation of the HOMO level. On the other hand, the fusion of the DCV group onto the vicinal thiophene ring by an ortho-phenylene bridge allows for a specific fine-tuning of the LUMO level. The electronic properties of the molecules were analyzed by using UV/Vis spectroscopy and cyclic voltammetry and the compounds were evaluated as donor materials in basic bilayer planar heterojunction solar cells by using C60 as acceptor material. The relationships between the electronic properties of the donors and the performance of the corresponding photovoltaic devices are discussed. Bilayer planar heterojunction solar cells that used reference compound 1 and C70 afforded power-conversion efficiencies of up to 3.7 %.

  11. Solution Processed Organic Photovoltaic Cells Using D-A-D-A-D Type Small Molecular Donor Materials with Benzodithiophene and Diketopyrrolopyrrole Units.

    Science.gov (United States)

    Park, Sangman; Nam, So Yeon; Suh, Dong Hack; Lee, Jaemin; Lee, Changjin; Yoon, Sung Cheol

    2016-03-01

    Organic photovoltaic Cells (OPVs) have been considered to be a next-generation energy source to overcome exhaustion of resources. Currently, OPVs are developed based on two types of donor material with polymer and small molecule. Polymeric donor materials have shown better power conversion efficiency (PCE) than small molecular donor materials, since it's easy to control the morphology of photoactive film. However, the difficulty in synthetic reproducibility and purification of polymeric donor were main drawback to overcome. And then, recently small molecule donor materials have been overcome bad morphology of OPVs film by using appropriate alkyl substituents and relatively long conjugation system. In this study, we designed and synthesized D-A-D-A-D type small molecular donor materials containing alternatively linked benzodithiophene (BDT) and diketopyrrolopyrrole (DPP) units. Also, we studied on the effect of photovoltaic performance of prepared small molecular D-A-D-A-D type donor with variation of thiophene links and with/without hexyl substituent. Our small molecular donors showed HOMO energy levels from -5.26 to -5.34 eV and optical bandgaps from 1.70 to 1.87 eV by CV (cyclic voltammetry) and UV/Vis spectroscopy, respectively. Finally, 3.4% of PCE can be obtained using a mixture of BDT(DPP)2-T2 and PCBM as an active layer with a Voc of 0.78 V, a Jsc of 9.72 mA/cm2, and a fill factor of 0.44 under 100 mW/cm2 AM 1.5G simulated light. We will discuss the performance of D-A-D-A-D type small molecular donor based OPVs with variation of both terminal substituents.

  12. New electroactive polymers with electronically isolated 3,6,9-triarylcarbazole units as efficient hole transporting materials for organic light emitting diodes

    Science.gov (United States)

    Griniene, R.; Tavgeniene, D.; Baranauskyte, U.; Xie, Z.; Zhang, B.; Gelzinis, A.; Grigalevicius, S.

    2017-04-01

    Polyethers containing electronically isolated 3,6,9-triarylcarbazole moieties have been synthesized by the multi-step synthetic procedures. A polymer containing unsubstituted carbazole rings was also prepared for comparison of properties. Full characterization of the materials is presented. The new polymers represent materials of high thermal stability with initial thermal degradation temperatures exceeding 367 °C. The high glass transition temperatures of the amorphous materials were in the rage of 133-146 °C. The electron photoemission spectra of thin layers of the polymers showed ionization potentials in the range of 5.52-5.6 eV. Hole-transporting properties of the electroactive materials were tested in the structures of organic light emitting diodes (OLEDs) with tris(quinolin-8-olato)aluminium as the green emitter and electron transporting material. The OLED devices in general exhibited rather low turn-on voltages of 3.2-4.2 V, high maximum brightness of 4910-7500 cd/m2 and luminous efficiency of 1.7-3.1 cd/A. It was confirmed that the devices containing the polymers with 3,6,9-triarylcarbazole moieties demonstrate considerably better OLED performance than that of device with polymer containing unsubstituted carbazole rings due to its higher ionization potential and accordingly worse hole injecting properties. The device containing hole-transporting layer of polymer with 3,6-di(1-naphthyl)-9-phenylcarbazole units exhibited the best overall performance with rather low turn on voltage of 4.4 V, maximum photometric efficiency exceeding 3.1 cd/A and maximum brightness of about 7500 cd/m2.

  13. Road density

    Data.gov (United States)

    U.S. Environmental Protection Agency — Road density is generally highly correlated with amount of developed land cover. High road densities usually indicate high levels of ecological disturbance. More...

  14. The effect of different restorative and abutment materials on marginal and internal adaptation of three-unit cantilever implant-supported fixed partial dentures: an in vitro study.

    Science.gov (United States)

    Kahramanoğlu, Erkut; Kulak-Özkan, Yasemin

    2013-12-01

    Passive fit is generally assumed to be a significant prerequisite for long-term implant success. The aim of this study was to evaluate the precision fit of three-unit implant-supported fixed partial dentures with different restorative and abutment materials on two implant systems: the Straumann and Astra Tech. Two mandibular epoxy resin models (one for each implant system) were fabricated, and two implants were inserted at the first and second molar region. Poly(vinyl siloxane) impression material was used to make the dental impression. For each implant system, fifteen models were fabricated, and each group was divided into three subgroups (group 1: titanium abutment with metal framework, group 2: titanium abutment with zirconium framework, group 3: zirconium abutment with zirconium framework). The replica technique was used to examine the marginal and internal gap values. For each restoration, 20 measurements were performed, totaling 1200 measurements for all groups. Data were evaluated statistically using ANOVA and LSD post hoc test (p study, marginal measurement values were found to be 46 to 87 μm. The marginal discrepancy of the tested materials could be considered clinically acceptable. © 2013 by the American College of Prosthodontists.

  15. Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States: Model of predicted nitrate concentration in U.S. ground water used for drinking (simulation depth 50 meters) -- Input data set for population density (gwava-dw_popd)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents 1990 block group population density, in people per square kilometer, in the conterminous United States. This data set represents The data...

  16. Influence of different light-curing units on the surface roughness of restorative materials: in situ study

    Directory of Open Access Journals (Sweden)

    Juliane Cristina Ciccone-Nogueira

    2007-09-01

    Full Text Available The aim of this study was to evaluate the influence of different light sources (LED and Halogen lamp on the roughness (superficial of composite resin (Filtek Z250, Filtek P60, Charisma and Durafill varying post-irradiation times, in an in situ experiment. For this purpose, 80 specimens were made in polyurethane moulds. Ten volunteers without medicament use and good oral condition were selected and from them study moulds were obtained. A palatal intra-oral acrylic resin appliance was made for each of the subjects of the experiment. In each appliance, two specimens of each material were fixed (LED/Halogen lamp - control group. Roughness tests were performed immediately and 30 days after initial light-curing. Statistical analysis was performed using ANOVA. Statistically significant difference was observed only between post-irradiation times, where the 30th day showed the highest roughness values. It be concluded that roughness was influenced only by post-irradiation times, presenting the 30- days period inferior behavior.

  17. Materials considerations in the design of a metal-hydride heat pump for an advanced extravehicular mobility unit

    Science.gov (United States)

    Liebert, B. E.

    1986-01-01

    A metal-hydride heat pump (HHP) has been proposed to provide an advanced regenerable nonventing thermal sink for the liquid-cooled garment worn during an extravehicular activity (EVA). The conceptual design indicates that there is a potential for significant advantages over the one presently being used by shuttle crew personnel as well as those that have been proposed for future use with the space station. Compared to other heat pump designs, a HHP offers the potential for extended use with no electrical power requirements during the EVA. In addition, a reliable, compact design is possible due to the absence of moving parts other than high-reliability check valves. Because there are many subtleties in the properties of metal hydrides for heat pump applications, it is essential that a prototype hydride heat pump be constructed with the selected materials before a committment is made for the final design. Particular care must be given to the evaporator heat exchanger worn by the astronaut since the performance of hydride heat pumps is generally heat transfer limited.

  18. Optimizing LED lighting for space plant growth unit: Joint effects of photon flux density, red to white ratios and intermittent light pulses

    Science.gov (United States)

    Avercheva, O. V.; Berkovich, Yu. A.; Konovalova, I. O.; Radchenko, S. G.; Lapach, S. N.; Bassarskaya, E. M.; Kochetova, G. V.; Zhigalova, T. V.; Yakovleva, O. S.; Tarakanov, I. G.

    2016-11-01

    The aim of this work were to choose a quantitative optimality criterion for estimating the quality of plant LED lighting regimes inside space greenhouses and to construct regression models of crop productivity and the optimality criterion depending on the level of photosynthetic photon flux density (PPFD), the proportion of the red component in the light spectrum and the duration of the duty cycle (Chinese cabbage Brassica сhinensis L. as an example). The properties of the obtained models were described in the context of predicting crop dry weight and the optimality criterion behavior when varying plant lighting parameters. Results of the fractional 3-factor experiment demonstrated the share of the PPFD level participation in the crop dry weight accumulation was 84.4% at almost any combination of other lighting parameters, but when PPFD value increased up to 500 μmol m-2 s-1 the pulse light and supplemental light from red LEDs could additionally increase crop productivity. Analysis of the optimality criterion response to variation of lighting parameters showed that the maximum coordinates were the following: PPFD = 500 μmol m-2 s-1, about 70%-proportion of the red component of the light spectrum (PPFDLEDred/PPFDLEDwhite = 1.5) and the duty cycle with a period of 501 μs. Thus, LED crop lighting with these parameters was optimal for achieving high crop productivity and for efficient use of energy in the given range of lighting parameter values.

  19. Bion's Notes on memory and desire--its initial clinical reception in the United States: a note on archival material.

    Science.gov (United States)

    Aguayo, Joseph

    2014-10-01

    While Bion's 1967 memory and desire paper reflected a crucial episode in his clinical thinking during his epistemological period, it was also central to his evolution as a Kleinian psychoanalyst who worked with seriously disturbed adult patients. The author explicates and contextualizes these claims with a new archival document, the Los Angeles Seminars delivered by Bion in April 1967, and the full-length version of Notes on memory and desire. Bion here instigated a radical departure from years of theory-laden work when he made his clinical work and ideas accessible to a new audience of American Freudian analysts. While this new group was keenly interested to hear about Bion's clinical technique with both borderline and psychotic patients, there were varied reactions to Bion's ideas on the technical implications of the analyst's abandonment of memory and desire. Both the Los Angeles Seminars and Notes elicited responses ranging from bewilderment, admiration to skepticism amongst his audience of listeners and readers. These materials also however allow for a more complete and systematic presentation of important ideas about analytic technique - and while his ideas in this domain have been long valued and known by many psychoanalysts, this contribution stresses the crucial aspect of the reception of his ideas about technique in a particular American context. American analysts gained a much more explicit idea of how Bion worked analytically, how he listened, formulated interpretations and factored in the analyst's listening receptivity in the here-and-now. The author concludes with a consideration of the importance of Bion's American reception in 1967.

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

    Science.gov (United States)

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

    2009-01-01

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

  1. Optimizing LED lighting for space plant growth unit: Joint effects of photon flux density, red to white ratios and intermittent light pulses.

    Science.gov (United States)

    Avercheva, O V; Berkovich, Yu A; Konovalova, I O; Radchenko, S G; Lapach, S N; Bassarskaya, E M; Kochetova, G V; Zhigalova, T V; Yakovleva, O S; Tarakanov, I G

    2016-11-01

    The aim of this work were to choose a quantitative optimality criterion for estimating the quality of plant LED lighting regimes inside space greenhouses and to construct regression models of crop productivity and the optimality criterion depending on the level of photosynthetic photon flux density (PPFD), the proportion of the red component in the light spectrum and the duration of the duty cycle (Chinese cabbage Brassica сhinensis L. as an example). The properties of the obtained models were described in the context of predicting crop dry weight and the optimality criterion behavior when varying plant lighting parameters. Results of the fractional 3-factor experiment demonstrated the share of the PPFD level participation in the crop dry weight accumulation was 84.4% at almost any combination of other lighting parameters, but when PPFD value increased up to 500µmol m(-2)s(-1) the pulse light and supplemental light from red LEDs could additionally increase crop productivity. Analysis of the optimality criterion response to variation of lighting parameters showed that the maximum coordinates were the following: PPFD = 500µmol m(-2)s(-1), about 70%-proportion of the red component of the light spectrum (PPFDLEDred/PPFDLEDwhite = 1.5) and the duty cycle with a period of 501µs. Thus, LED crop lighting with these parameters was optimal for achieving high crop productivity and for efficient use of energy in the given range of lighting parameter values. Copyright © 2016 The Committee on Space Research (COSPAR). Published by Elsevier Ltd. All rights reserved.

  2. Corrective Action Investigation Plan for Corrective Action Unit 529: Area 25 Contaminated Materials, Nevada Test Site, Nevada, Rev. 0, Including Record of Technical Change No. 1

    Energy Technology Data Exchange (ETDEWEB)

    U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office

    2003-02-26

    This Corrective Action Investigation Plan contains the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office's approach to collect the data necessary to evaluate corrective action alternatives appropriate for the closure of Corrective Action Unit (CAU) 529, Area 25 Contaminated Materials, Nevada Test Site (NTS), Nevada, under the Federal Facility Agreement and Consent Order. CAU 529 consists of one Corrective Action Site (25-23-17). For the purpose of this investigation, the Corrective Action Site has been divided into nine parcels based on the separate and distinct releases. A conceptual site model was developed for each parcel to address the translocation of contaminants from each release. The results of this investigation will be used to support a defensible evaluation of corrective action alternatives in the corrective action decision document.

  3. Influence of flavour absorption by food-packaging materials (low-density polyethylene, polycarbonate and polyethylene terephthalate) on taste perception of a model solution and orange juice

    NARCIS (Netherlands)

    Willige, van R.W.G.; Linssen, J.P.H.; Legger, A.; Voragen, A.G.J.

    2003-01-01

    The influence of flavour absorption by low-density polyethylene (LDPE), polycarbonate (PC) and polyethylene terephthalate (PET) on taste perception of a model solution containing seven flavour compounds and orange juice in glass bottles was studied with and without pieces of the respective plastic

  4. Bis[3-(5-nitroimino-1,2,4-triazolate)]-based energetic salts: synthesis and promising properties of a new family of high-density insensitive materials.

    Science.gov (United States)

    Wang, Ruihu; Xu, Hongyan; Guo, Yong; Sa, Rongjian; Shreeve, Jean'ne M

    2010-09-01

    Bis[3-(5-nitroimino-1,2,4-triazolate)]-based energetic salts were synthesized in a simple, straightforward manner. They exhibit low solubility in available solvents, high hydrolytic stability, excellent thermal stability, high density, positive heat of formation, low shock sensitivity, and excellent detonation properties. The physical and energetic properties of some salts are similar and even superior to those of RDX.

  5. Influence of flavour absorption by food-packaging materials (low-density polyethylene, polycarbonate and polyethylene terephthalate) on taste perception of a model solution and orange juice

    NARCIS (Netherlands)

    Willige, van R.W.G.; Linssen, J.P.H.; Legger, A.; Voragen, A.G.J.

    2003-01-01

    The influence of flavour absorption by low-density polyethylene (LDPE), polycarbonate (PC) and polyethylene terephthalate (PET) on taste perception of a model solution containing seven flavour compounds and orange juice in glass bottles was studied with and without pieces of the respective plastic f

  6. Thoughts on Strengthening Material Management Work of Geological Exploration Units%对地勘单位加强材料管理工作的思考

    Institute of Scientific and Technical Information of China (English)

    袁哲

    2013-01-01

    Geological exploration unit is gradually turned to self-ifnancing enterprise management pattern. So it is of great signiifcance for us to attache great importance to the material management work. This paper first points out some flaws existed in the links of materials purchased, daily management inventory materials, the management of using the material, and financial accounting of material. On account of this, this paper proposes that we should set up the team consciousness, and strengthen the sense of responsibility education. At the same time, we should strengthen the system construction and the business skills training by using the method of reform, intensify the internal surveillance in feasible measures. In addition, the computer should be allocated for the daily management of storage materials.%地勘单位正逐步转向“自负盈亏”的企业化经营管理模式,加强、重视材料管理工作具有重要意义。地勘单位材料的有效管理是地勘单位经营管理的基础环节,目前地勘单位在材料的购进环节、库存材料日常管理环节、在用材料的管理环节、在材料的财务核算环节存在一些漏洞。针对“四不管”的现象,应树立团队意识,加强责任心教育;应用改革的办法强化制度建设,加强业务技能学习培训;以切实可行的措施强化内部监督;可配置计算机进行在库材料的日常管理工作。

  7. Estimating the effect of a phase change material on the performance of a photovoltaic unit using a five parameter model approach

    Directory of Open Access Journals (Sweden)

    Panagiotis Kladisios, Athina Stegou-Sagia

    2017-01-01

    Full Text Available Photovoltaic modules operate under a large range of conditions. This, combined with the fact that manufacturers provide electrical parameters at specific conditions (STC, Standard Test Conditions renders the prediction of a PV module’s power efficiency very difficult. The most common model for calculating the electric characteristics and, consequently, the generated power of a photovoltaic unit under real transient conditions is the five-parameter model. It is noteworthy that this model demands a relatively small amount of data that are normally available from the manufacturer. The purpose of this paper is to determine the actual benefit in the power efficiency of a photovoltaic unit that has its cell temperature reduced using a phase change material. All approaches of the five-parameter model involve simulating the solar cell, photovoltaic module or photovoltaic array with an one-diode equivalent electrical circuit. The operation of such a circuit is defined by a characteristic I-V equation which contains five parameters: the photocurrent I0, the reverse saturation current Il, the series resistance Rs, the parallel resistance Rp and, depending on the approach, either the diode’s ideality factor m or the modified ideality factor α. For every pair of cell temperature T and solar radiation G, a new characteristic I-V is in effect and, therefore, the above parameters must be calculated anew using correlations between reference and non-reference values of the parameters.

  8. Final Report for the 1st Surveillance Test of the Reactor Pressure Vessel Material (CAPSULE 2) of Ulchin Nuclear Power Plant Unit 3

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Kee Ok; Kim, Byoung Chul; Lee, Sam Lai (and others)

    2006-12-15

    Surveillance testing for reactor vessel materials is performed in order to evaluate the irradiation embrittlement due to neutrons during operation and set the condition of safe operation of nuclear reactor. The 1st surveillance testing was performed completely by Korea Atomic Energy Research Institute at Taejon after the capsule was transported from Ulchin site including its removal from reactor. Fast neutron fluences for capsules were calculated and various testing including mechanical and chemistry analysis were performed in order to evaluate the integrity of Ulchin unit 3 reactor vessel during the operation until life time. The evaluation results are as follows; Fast neutron fluences for capsule 2 is 4.674E 18n/cm{sup 2}. The bias factor, the ratio of calculation/measurement, was 0.920 for the 1st testing and the calculational uncertainty,7.0% satisfied the requirement of USNRC Reg.Guide 1.190, 20%. The best estimated neutron fluence for reactor vessel inside surface was 3.913E 18n/cm{sup 2} based on the end of 6th fuel cycle and it was predicted that the fluences of vessel inside surface at 16 and 32EFPY would reach 9.249E 18 and 1.834E 19n/cm{sup 2} based on the current calculation. The result through this analysis for Ulchin unit 3 showed that there would be no problem for the pressurized thermal shock(PTS) during the operation until design life.

  9. Final Report for the 1st Surveillance Test of the Reactor Pressure Vessel Material (Capsule 2) of Ulchin Nuclear Power Plant Unit 4

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Kee Ok; Kim, Byoung Chul; Lee, Sam Lai (and others)

    2007-04-15

    Surveillance testing for reactor vessel materials is performed in order to evaluate the irradiation embrittlement due to neutrons during operation and set the condition of safe operation of nuclear reactor. The 1st surveillance testing was performed completely by Korea Atomic Energy Research Institute at Daejon after the capsule was transported from Ulchin site including its removal from reactor. Fast neutron fluences for capsules were calculated and various testing including mechanical and chemistry analysis were performed in order to evaluate the integrity of Ulchin Unit 4 reactor vessel during the operation until life time. The evaluation results are as follows; Fast neutron fluences for capsule 2 is 4.306E+18n/cm{sup 2}. The bias factor, the ratio of calculation/measurement, was 0.918 for the 1st testing and the calculational uncertainty,7.0% satisfied the requirement of USNRC Reg.Guide 1.190, 20%. The best estimated neutron fluence for reactor vessel inside surface was 3.615E+18n/cm{sup 2} based on the end of 6th fuel cycle and it was predicted that the fluences of vessel inside surface at 16 and 32EFPY would reach 8.478E+18 and 1.673E+19n/cm{sup 2} based on the current calculation. The result through this analysis for Ulchin Unit 4 showed that there would be no problem for the pressurized thermal shock(PTS) during the operation until design life.

  10. Corrosion Analysis and Material Selection for Anti-corrosion in Hydrotreating Units%加氢装置的腐蚀分析和选材防腐

    Institute of Scientific and Technical Information of China (English)

    李黎

    2016-01-01

    The rapid development of hydrotreating technology and the inferior feed oil make corrosion problems of equipments and pipelines increasingly prominent in the hydrotreating plant. Leak accidents happen from time to time, affecting the running safety of the device. New requirements to the material selection of the hydrotreating unit were put forward. Common corrosion types in hydrotreating unit were analyzed, and then preventive measures were given.%加氢技术的飞速发展和加氢原料的劣质化使得加氢装置的设备及管道腐蚀问题愈显突出,泄露等事故时有发生,合理的选材设计对加氢装置的安全长周期运行至关重要。首先分析了加氢装置里典型的腐蚀类型,然后从选材角度给出了防护措施。

  11. Corrective Action Decision Document for Corrective Action Unit 166: Storage Yards and Contaminated Materials, Nevada Test Site, Nevada with Errata Sheet

    Energy Technology Data Exchange (ETDEWEB)

    Grant Evenson

    2007-03-01

    This Corrective Action Decision Document (CADD) has been prepared for Corrective Action Unit (CAU) 166, Storage Yards and Contaminated Materials, in accordance with the Federal Facility Agreement and Consent Order (1996). The corrective action sites (CASs) are located in Areas 2, 3, 5, and 18 of the Nevada Test Site, Nevada. Corrective Action Unit 166 is comprised of the following CASs: • 02-42-01, Cond. Release Storage Yd - North • 02-42-02, Cond. Release Storage Yd - South • 02-99-10, D-38 Storage Area • 03-42-01, Conditional Release Storage Yard • 05-19-02, Contaminated Soil and Drum • 18-01-01, Aboveground Storage Tank • 18-99-03, Wax Piles/Oil Stain The purpose of this CADD is to identify and provide the rationale for the recommendation of a corrective action alternative (CAA) for the seven CASs within CAU 166. Corrective action investigation (CAI) activities were performed from July 31, 2006, through February 28, 2007, as set forth in the CAU 166 Corrective Action Investigation Plan (NNSA/NSO, 2006).

  12. Porous Carbon Materials Based on Graphdiyne Basis Units by the Incorporation of the Functional Groups and Li Atoms for Superior CO2 Capture and Sequestration.

    Science.gov (United States)

    Dang, Yong; Guo, Wenyue; Zhao, Lianming; Zhu, Houyu

    2017-09-06

    The graphdiyne family has attracted a high degree of concern because of its intriguing and promising properties. However, graphdiyne materials reported to date represent only a tiny fraction of the possible combinations. In this work, we demonstrate a computational approach to generate a series of conceivable graphdiyne-based frameworks (GDY-Rs and Li@GDY-Rs) by introducing a variety of functional groups (R = -NH2, -OH, -COOH, and -F) and doping metal (Li) in the molecular building blocks of graphdiyne without restriction of experimental conditions and rapidly screen the best candidates for the application of CO2 capture and sequestration (CCS). The pore topology and morphology and CO2 adsorption and separation properties of these frameworks are systematically investigated by combining density functional theory (DFT) and grand canonical Monte Carlo (GCMC) simulations. On the basis of our computer simulations, combining Li-doping and hydroxyl groups strategies offer an unexpected synergistic effect for efficient CO2 capture with an extremely CO2 uptake of 4.83 mmol/g at 298 K and 1 bar. Combined with its superior selectivity (13 at 298 K and 1 bar) for CO2 over CH4, Li@GDY-OH is verified to be one of the most promising materials for CO2 capture and separation.

  13. Computational studies on the crystal structure, thermodynamic properties, detonation performance, and pyrolysis mechanism of 2,4,6,8-tetranitro-1,3,5,7-tetraazacubane as a novel high energy density material.

    Science.gov (United States)

    Wang, Fang; Du, Hongchen; Zhang, Jianying; Gong, Xuedong

    2011-10-27

    Studies have suggested that octanitrocubane (ONC) is one of the most powerful non-nuclear high energy density material (HEDM) currently known. 2,4,6,8-Tetranitro-1,3,5,7-tetraazacubane (TNTAC) studied in this work may also be a novel HEDM due to its high nitrogen content and crystal density. Density functional theory and molecular mechanics methods have been employed to study the crystal structure, IR spectrum, electronic structure, thermodynamic properties, gas-phase and condensed-phase heat of formation, detonation performance, and pyrolysis mechanism of TNTAC. The TNTAC has a predicted density of about 2.12 g/cm(3), and its detonation velocity (10.42 km/s) and detonation pressure (52.82 GPa) are higher than that of ONC. The crystalline packing is P2(1)2(1)2(1), and the corresponding cell parameters are Z = 4, a = 8.87 Å, b = 8.87 Å, and c = 11.47 Å. Both the density of states of the predicted crystal and the bond dissociation energy of the molecule in gas phase show that the cage C-N bond is the trigger bond during thermolysis. The activation energy of the pyrolysis initiation reaction obtained from the B3LYP/6-311++G(2df,2p) level is 125.98 kJ/mol, which indicates that TNTAC meets the thermal stability request as an exploitable HEDM.

  14. Screened-exchange density functional theory description of the electronic structure and phase stability of the chalcopyrite materials AgInSe2 and AuInSe2

    Science.gov (United States)

    Kim, Namhoon; Martin, Pamela Peña; Rockett, Angus A.; Ertekin, Elif

    2016-04-01

    We present a systematic assessment of the structural properties, the electronic density of states, the charge densities, and the phase stabilities of AgInSe2 and AuInSe2 using screened-exchange hybrid density functional theory, and compare their properties to those of CuInSe2. For AgInSe2, hybrid density functional theory properly captures several experimentally measured properties, including the increase in the band gap and the change in the direction of the lattice distortion parameter u in comparison to CuInSe2. While the electronic properties of AuInSe2 have not yet been experimentally characterized, we predict it to be a small gap (≈0.15 eV) semiconductor. We also present the phase stability of AgInSe2 and AuInSe2 according to screened-exchange density functional theory, and compare the results to predictions from conventional density functional theory, results tabulated from several online materials data repositories, and experiment (when available). In comparison to conventional density functional theory, the hybrid functional predicts phase stabilities of AgInSe2 in better agreement with experiment: discrepancies in the calculated formation enthalpies are reduced by approximately a factor of 3, from ≈0.20 eV/atom to ≈0.07 eV/atom, similar to the improvement observed for CuInSe2. We further predict that AuInSe2 is not a stable phase, and can only be present under nonequilibrium conditions.

  15. Lung density

    DEFF Research Database (Denmark)

    Garnett, E S; Webber, C E; Coates, G

    1977-01-01

    The density of a defined volume of the human lung can be measured in vivo by a new noninvasive technique. A beam of gamma-rays is directed at the lung and, by measuring the scattered gamma-rays, lung density is calculated. The density in the lower lobe of the right lung in normal man during quiet...... breathing in the sitting position ranged from 0.25 to 0.37 g.cm-3. Subnormal values were found in patients with emphsema. In patients with pulmonary congestion and edema, lung density values ranged from 0.33 to 0.93 g.cm-3. The lung density measurement correlated well with the findings in chest radiographs...... but the lung density values were more sensitive indices. This was particularly evident in serial observations of individual patients....

  16. Development of optimum process for electron beam cross-linking of high density polyethylene thermal energy storage pellets, process scale-up and production of application qualities of material

    Science.gov (United States)

    Salyer, I. O.

    1980-01-01

    The electron irradiation conditions required to prepare thermally from stable high density polyethylene (HDPE) were defined. The conditions were defined by evaluating the heat of fusion and the melting temperature of several HDPE specimens. The performance tests conducted on the specimens, including the thermal cycling tests in the thermal energy storage unit are described. The electron beam irradiation tests performed on the specimens, in which the total radiation dose received by the pellets, the electron beam current, the accelerating potential, and the atmospheres were varied, are discussed.

  17. Shock-Absorbing Materials. Report 2. Cellular Concrete as a Backpacking Material.

    Science.gov (United States)

    The use of low-density cellular concrete, having an oven-try unit weight of 50 pcf or less, as a backpacking material for deeply buried protective...difficulty during prototype use of cellular concrete as a backpacking , such as lift heights, cold joints, temperature problems, and water-saturation problems, are also explored. (Author)

  18. Assessment of the failure behavior of dangerous goods containers made of high density polyethylene using relevant material parameters; Beurteilung des Versagensverhaltens von Gefahrengutbehaeltern aus Polyethylen hoher Dichte auf Basis relevanter Werkstoffkennwerte

    Energy Technology Data Exchange (ETDEWEB)

    Menrad, Andreas

    2013-09-01

    To obtain approval as dangerous goods packaging, different experimental tests are required to show the eligibility for the transportation of those goods. The data obtained from the material test performed on the pressed plates is not used to get absolute values for the failure time in an internal pressure test or the medium drop height. The goal is to see if there are changes in the behavior because a different HDPE is being used. All the jerrycans and pressed plates were specially made of four different materials to gain knowledge about the material properties. The plates and jerrycans were made of resin from the same batch to prevent variations caused by batch differences. The wall thickness is decisive and, therefore packagings were analyzed using computer tomography and the fringe projection technique. The results were compared to the magnetostatic measurement technique. The deformation under internal pressure was measured by digital image correlation. Deformations in the radial direction and the equivalent strains were determined. These deformations, strains, and their acceleration due to the swelling effect could be reproduced in the finite element analysis by using the temperature in the material model. The resistance against both internal pressure and absorption depend on the density of the material. Conditioning at elevated temperatures causes post crystallization and reduces internal stresses. Differences in the densities of the materials can be determined by using plates manufactured by compression molding. A higher density leads to a better performance under internal pressure. A correlation could be proved between the medium failure drop height (50 % of the packagings fail because of a crack) and the tensile impact strength of notched specimens cut out of the jerrycans side walls and the notched impact strength (NIS) of pressed plates. A higher NIS leads to a higher medium failure drop height. A low resistance against oxidative degradation will reduce

  19. The Weighted Burgers Vector: a new quantity for constraining dislocation densities and types using electron backscatter diffraction on 2D sections through crystalline materials.

    Science.gov (United States)

    Wheeler, J; Mariani, E; Piazolo, S; Prior, D J; Trimby, P; Drury, M R

    2009-03-01

    The Weighted Burgers Vector (WBV) is defined here as the sum, over all types of dislocations, of [(density of intersections of dislocation lines with a map) x (Burgers vector)]. Here we show that it can be calculated, for any crystal system, solely from orientation gradients in a map view, unlike the full dislocation density tensor, which requires gradients in the third dimension. No assumption is made about gradients in the third dimension and they may be non-zero. The only assumption involved is that elastic strains are small so the lattice distortion is entirely due to dislocations. Orientation gradients can be estimated from gridded orientation measurements obtained by EBSD mapping, so the WBV can be calculated as a vector field on an EBSD map. The magnitude of the WBV gives a lower bound on the magnitude of the dislocation density tensor when that magnitude is defined in a coordinate invariant way. The direction of the WBV can constrain the types of Burgers vectors of geometrically necessary dislocations present in the microstructure, most clearly when it is broken down in terms of lattice vectors. The WBV has three advantages over other measures of local lattice distortion: it is a vector and hence carries more information than a scalar quantity, it has an explicit mathematical link to the individual Burgers vectors of dislocations and, since it is derived via tensor calculus, it is not dependent on the map coordinate system. If a sub-grain wall is included in the WBV calculation, the magnitude of the WBV becomes dependent on the step size but its direction still carries information on the Burgers vectors in the wall. The net Burgers vector content of dislocations intersecting an area of a map can be simply calculated by an integration round the edge of that area, a method which is fast and complements point-by-point WBV calculations.

  20. Causes of failure to achieve the low density lipoprotein cholesterol therapeutic target in patients with high and very high vascular risk controlled in Lipid and Vascular Risk Units. EROMOT study.

    Science.gov (United States)

    Morales, Clotilde; Plana, Núria; Arnau, Anna; Matas, Laia; Mauri, Marta; Vila, Àlex; Vila, Lluís; Soler, Cristina; Montesinos, Jesús; Masana, Lluís; Pedro-Botet, Juan

    2017-09-12

    Determination of the level of achievement of the low density lipoprotein cholesterol (LDL-C) therapeutic target in patients with high and very high vascular risk treated in Lipid Units, as well as the causes of non-achievement. Multicentre retrospective observational study that included patients over 18 years with high and very high vascular risk, according to the criteria of the 2012 European Guidelines on Cardiovascular Disease Prevention, referred consecutively to Lipid Units between January and June 2012 and with follow-up two years after the first visit. The study included a total of 243 patients from 16 lipid units. The mean age was 52.2 years (SD 13.7), of whom 62.6% were males, and 40.3% of them were very high risk. At the first visit, 86.8% (25.1% in combination) and 95.0% (47.3% in combination) in the second visit (P<.001) were treated with lipid-lowering treatment. The therapeutic target was achieved by 28% (95 CI: 22.4-34.1). As regards the causes of non-achievement, 24.6% were related to the medication (10.3% maximum tolerated dose and 10.9% due to the appearance of adverse effects), 43.4% due to the physician (19.4% by inertia, 31.7% considering that target already reached), and 46.9% due to the patient, highlighting the therapeutic non-compliance (13,4%). LDL-C targets were achieved in about one-third of patients. The low adherence of the patient, followed by medical inertia are the most frequent causes that can explain these results. Copyright © 2017 Sociedad Española de Arteriosclerosis. Publicado por Elsevier España, S.L.U. All rights reserved.

  1. Discussion on Selection of Crude Distillation Unit Hot Overhead Condenser Tube Bundle Material%浅谈常顶热交换器管束选材

    Institute of Scientific and Technical Information of China (English)

    刘洋; 高威

    2016-01-01

    炼油企业常减压装置中的常顶热交换器管束腐独问题一直比较突出,对常减压装置安稳长周期运行构成了严重威胁。通过查找近年来多套常减压装置常顶热交换器管束选材及使用情况,总结归纳了常用的3种常顶热交换器管束材质09Cr2AlMoRE、双相钢2205、钛在对应使用工况下的注意事项,经过对多套常减压装置常顶热交换器管束腐蚀情况的分析,列出了每种常减压装置常顶热交换器管束材质的腐蚀机理以及改进措施,对今后常减压装置常顶热交换器管束选材具有一定的参考意义。%The corrosion problem of crude distillation unit (CDU ) hot overhead condenser tube has been more prominent for many years ,this problem is a serious threat for long‐term operation constitutes of CDU .For finding CDU hot overhead condenser tubes material selection in several sets of CDU ,and using of CDU hot overhead condenser tube in each refinery after production op‐erations ,this article summarizes the notes of CDU hot overhead condenser tubes commonly used three types of material (09Cr2AlMoRE ,dual‐phase steel 2205 ,TA) under the corresponding use condition .By analysis of the corrosion of CDU hot overhead condenser tube in several sets of CDU ,CDU hot overhead condenser tubes corrosion mechanism and improvement measures of each type material were list in this text which has a certain reference significance in future for the CDU hot overhead condenser tube material selection in CDU .

  2. Comparative analysis of phraseological units of Body parts lexico-semantic field (on the material of Arabic, Avar and Russian languages

    Directory of Open Access Journals (Sweden)

    Зайнаб Ибрагимовна Исмаилова

    2011-06-01

    Full Text Available The article attempts to study phraseological units with somatic body parts component of the Arabic language in comparison with Аvar and Russian languages. The paper covers the following problems: the comparison of phraseological units of three unrelated languages, the exposure of semantic peculariaties of analyzed somatic phraseological units, the description of structural-grammatical composition of Arabic, Avar and Russian somatic phraseological units, the research of interlanguage equivalence of somatic phraseological units in compared languages.

  3. The 4th surveillance test and evaluation of the reactor pressure vessel material (capsule W) of Younggwang nuclear power plant unit1

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Byoung Chul; Lee, Sam Lai; Choi, Kwon Jae [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2001-08-01

    Surveillance testing for reactor vessel materials is performed in order to evaluate the irradiation embrittlement due to neutrons during operation and set the condition of safe operation of nuclear reactor. The 4th surveillance testing was performed completely by Korea Atomic Energy Research Institute at Taejeon after the capsule was transported from Yonggwang site including its removal from reactor. Fast neutron fluences for capsules were calculated and various testing including mechanical and chemistry analysis were performed in order to evaluate the integrity of Yonggwang unit 1 reactor vessel during the operation until life time. The evaluation results are as follows; Fast neutron fluences for capsules U, V, X and W are 5.555E+18, 1.662E+19, 3.358E+19, and 4.521E+19 n/cm{sup 2}, respectively. The bias factor, the ratio of measurement versus calculation, was 0.859 for the 1st through 4th testing and the calculational uncertainty, 11.80% satisfied the requirement of USNRC Reg.Guide 1.190, 20%. The best estimated neutron fluence for reactor vessel inside surface was 1.551E+19 n/cm{sup 2} based on the end of 12th fuel cycle and it was predicted that the fluences of vessel inside surface at 32, 40, 48 and 56EFPY would reach 3.929E+19, 4.880E+19, 5.831E+19 and 6.782E+19 n/cm{sup 2} based on the current calculation. The result through this analysis for Yonggwang unit 1 showed that there would be no problem for the pressurized thermal shock(PTS) during the operation until design life. 4 refs., 41 figs., 35 tabs. (Author)

  4. Final report for the 5th surveillance test of the reactor pressure vessel material (capsule Y) of Yonggwang Nuclear Power Plant unit 2

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sam Lai; Kim, ByoungChul; Chang, Kee Ok (and others)

    2006-02-15

    Surveillance testing for reactor vessel materials is performed in order to evaluate the irradiation embrittlement due to neutrons during operation and set the condition of safe operation of nuclear reactor. The 5th surveillance testing was performed completely by Korea Atomic Energy Research Institute at Daejeon after the capsule was transported from Yonggwang site including its removal from reactor. Fast neutron fluences for capsules were calculated and various testing including mechanical and chemistry analysis were performed in order to evaluate the integrity of Yonggwang unit 2 reactor vessel during the operation until life time. The evaluation results are as follows; Fast neutron fluences for capsules U, V, X, W and Y are 5.777E+18, 1.5371E+19, 3.7634E+19, 4.3045E+19, and 4.8662E+19n/cm{sup 2}, respectively. The bias factor, the ratio of calculation/measurement, was 0.953 for the 1st through 5th testing and the calculational uncertainty,7.2% satisfied the requirement of USNRC Reg.Guide 1.190, 20%. The best estimated neutron fluence for reactor vessel inside surface was 1.659E+19n/cm{sup 2} based on the end of 13th fuel cycle and it was predicted that the fluences of vessel inside surface at 32, 48, 56 and 64EFPY would reach 3.625E+19, 5.293E+19, 6.127E+19 and 6.960E+19n/cm{sup 2} based on the current calculation. The result through this analysis for Yonggwang unit 2 showed that there would be no problem for the Pressurized Thermal Shock(PTS) during the operation until design life.

  5. The 4th surveillance test and evaluation of the reactor pressure vessel material (capsule W) of Yonggwang nuclear power plant unit 2

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Kee Ok; Kim, Byoung Chul; Lee, Sam Lai; Choi, Kwon Jae; Gong, Un Sik; Chang, Jong Hwa; Joo, Yong Sun; Ahn, Sang Bok; Hong, Joon Hwa [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2001-02-01

    Surveillance testing for reactor vessel materials is performed in order to evaluate the irradiation embrittlement due to neutrons during operation and set the condition of safe operation of nuclear reactor. The 4th surveillance testing was performed completely by Korea Atomic Energy Research Institute at Taejeon after the capsule was transported from Kori site including its removal from reactor. Fast neutron fluences for capsules were calculated and various testing including mechanical and chemistry analysis were performed in order to evaluate the integrity of Yonggwang unit 2 reactor vessel during the operation until life time. The evaluation results are as follows; Fast neutron fluences for capsules U, V, X and W are 5.762E+18, 1.5391E+19, 3.5119E+19, and 4.2610E+19 n/cm{sup 2}, respectively. The bias factor, the ratio of measurement versus calculation, was 0.899 for the 1st through 4th testing and the calculational uncertainty, 12.3% satisfied the requirement of USNRC Reg.Guide DG-1053, 20%. The best estimated neutron fluence for reactor vessel inside surface was 1.357E+19 n/cm{sup 2} based on the end of 11th fuel cycle and it was predicted that the fluences of vessel inside surface at 32, 40, 48 and 56EFPY would reach 3.525E+19, 4.337E+19, 5.148E+19 and 5.960E+19 n/cm{sup 2} based on the current calculation. The result through this analysis for Yonggwang unit 2 showed that there would be no problem for the pressurized thermal shock(PTS) during the operation until design life. 48 refs., 35 figs., 42 tabs. (Author)

  6. Generation of intense X-radiation and high-energy-density matter by laser-accelerated electrons; Erzeugung von intensiver Roentgenstrahlung und Materie hoher Energiedichte durch Laserbeschleunigte Elektronen

    Energy Technology Data Exchange (ETDEWEB)

    Schoenlein, Andreas

    2015-07-01

    Aim of this thesis was to study the processes of the interaction between highly intense short-pulse laser and matter. The focus lied thereby on the generation of intense X-radiation and warm dense matter. The studies performed for this thesis comprehend thereby the influence of laser parameters like energy, pulse length, focus size, and intensity as well as the influence of the target geometry on the interaction and generation of high-energy-density matter. In this thesis for this two selected experiments are presented. First a silver foil was used as target, in order to study the generation of radiation at 21 keV. Both bremsstrahlung and characteristic X-radiation were used in order to characterize the interaction. For the second experiment freely standing titanium wires were used as target. Hereby the focus lied on the characterization of the heated matter.

  7. Poly(vinylidene fluoride-co-hexafluoropropylene)-graft-poly(dopamine methacrylamide) copolymers: A nonlinear dielectric material for high energy density storage

    Science.gov (United States)

    Rahimabady, Mojtaba; Qun Xu, Li; Arabnejad, Saeid; Yao, Kui; Lu, Li; Shim, Victor P. W.; Gee Neoh, Koon; Kang, En-Tang

    2013-12-01

    A nonlinear dielectric poly(vinylidene fluoride-co-hexafluoropropylene)-graft-poly(dopamine methacrylamide) [P(VDF-HFP)-g-PDMA] graft copolymer with ultra-high energy density of 33 J/cm3 was obtained by thermally initiated radical graft polymerization. It was observed that the dielectric constant of the graft copolymer films was 63% higher than that of P(VDF-HFP), with a large dielectric breakdown strength (>850 MV/m). Theoretical analyses and experimental measurements showed that the significant improvement in the electric polarization was attributed to the introduction of the highly polarizable hydroxyl groups in the PDMA side chains, and the large breakdown strength arose from the strong adhesion bonding of the catechol-containing graft copolymer to the metal electrode.

  8. Studies of protein adsorption on implant materials in relation to biofilm formation I. Activity of Pseudomonas aeruginosa on Polypropylene and High density Polyethylene in presence of serum albumin

    CERN Document Server

    Sinha, S Dutta; Maity, P K; Tarafdar, S; Moulik, S P

    2014-01-01

    The surface of biomaterials used as implants are highly susceptible to bacterial colonization and subsequent infection. The amount of protein adsorption on biomaterials, among other factors, can affect the nature and quality of biofilms formed on them. The variation in the adsorption time of the protein on the biomaterial surface produces a phenotypic change in the bacteria by alteration of the production of EPS (exoplysaccharide) matrix. Knowledge of the effects of protein adsorption on implant infection will be very useful in understanding the chemistry of the biomaterial surfaces, which can deter the formation of biofilms. It is observed that the adsorption of BSA on the biomaterial surfaces increases with time and concentration, irrespective of their type and the nature of the EPS matrix of the bacterial biofilm is dependent on the amount of protein adsorbed on the biomaterial surface. The adsorption of protein (BSA) on the biomaterials, polypropylene (PP) and high density polyethylene (HDPE) has been stu...

  9. High energy density of Li3-xNaxV2(PO4)3/C cathode material with high rate cycling performance for lithium-ion batteries

    Science.gov (United States)

    Zuo, Zong-Lin; Deng, Jian-Qiu; Pan, Jin; Luo, Wen-Bin; Yao, Qing-Rong; Wang, Zhong-Min; Zhou, Huai-Ying; Liu, Hua-Kun

    2017-07-01

    A serials of micro-sized Li3-xNaxV2(PO4)3/C composite has been synthesized by sol-gel method, comprised of numerous primary nanocrystals. This structure can efficiently facilitate lithium-ion transport in secondary aggregated individual particles due to the short diffusion distance among primary nanocrystals, along with a high tap density. With the increasing of Na doping content, the structure evolution occurs in Li3-xNaxV2(PO4)3 from a single-phase structure to a two-phase structure. The appearance of rhombohedral phase can provide a larger free volume of the interstitial space, fastening ionic movement to offer an excellent high rate capability. Furthermore, Na doping can stabilize the rhombohedral structure of the V2(PO4)3 framework, leading to the remarkable cycling stability. Among all the composites, Li2.6Na0.4V2(PO4)3/C presents the best electrochemical performance with a high energy density of 478.8 Wh kg-1, delivering high initial discharge capacities of 121.6, 113.8 and 109.7 mAh g-1 at the rate of 5 C, 10 C and 20 C in a voltage range of 3.0 - 4.3 V, respectively. It also exhibit an excellent high rate cycling performance, with capacity retention of 85.9 %, 81.7 % and 76.5 % after 1000 cycles at the rate of 5 C, 10 C and 20 C in a voltage range of 3.0 - 4.3 V.

  10. MOF-derived crumpled-sheet-assembled perforated carbon cuboids as highly effective cathode active materials for ultra-high energy density Li-ion hybrid electrochemical capacitors (Li-HECs)

    Science.gov (United States)

    Banerjee, Abhik; Upadhyay, Kush Kumar; Puthusseri, Dhanya; Aravindan, Vanchiappan; Madhavi, Srinivasan; Ogale, Satishchandra

    2014-03-01

    Lithium ion hybrid capacitors (Li-HECs) have attracted significant attention for use in next generation advanced energy storage technologies to satisfy the demand of both high power density as well as energy density. Herein we demonstrate the use of very high surface area 3D carbon cuboids synthesized from a metal-organic framework (MOF) as a cathode material with Li4Ti5O12 as the anode for high performance Li-HECs. The energy density of the cell is ~65 W h kg-1 which is significantly higher than that achievable with commercially available activated carbon (~36 W h kg-1) and a symmetric supercapacitor based on the same MOF-derived carbon (MOF-DC ~20 W h kg-1). The MOF-DC/Li4Ti5O12 Li-HEC assembly also shows good cyclic performance with ~82% of the initial value (~25 W h kg-1) retained after 10 000 galvanostatic cycles under high rate cyclic conditions. This result clearly indicates that MOF-DC is a very promising candidate for future P-HEVs in a Li-HEC configuration.Lithium ion hybrid capacitors (Li-HECs) have attracted significant attention for use in next generation advanced energy storage technologies to satisfy the demand of both high power density as well as energy density. Herein we demonstrate the use of very high surface area 3D carbon cuboids synthesized from a metal-organic framework (MOF) as a cathode material with Li4Ti5O12 as the anode for high performance Li-HECs. The energy density of the cell is ~65 W h kg-1 which is significantly higher than that achievable with commercially available activated carbon (~36 W h kg-1) and a symmetric supercapacitor based on the same MOF-derived carbon (MOF-DC ~20 W h kg-1). The MOF-DC/Li4Ti5O12 Li-HEC assembly also shows good cyclic performance with ~82% of the initial value (~25 W h kg-1) retained after 10 000 galvanostatic cycles under high rate cyclic conditions. This result clearly indicates that MOF-DC is a very promising candidate for future P-HEVs in a Li-HEC configuration. Electronic supplementary information

  11. Measurement of hard tissue density of head phantom based on the HU by using CBCT

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Moon Sun; Kang, Dong Wan; Kim, Jae Duk [School of Dentistry, Chosun University, Gwangju (Korea, Republic of)

    2009-09-15

    The purpose of this study was to determine a conversion coefficient for Hounsfield Units(HU) to material density (g cm{sup -3}) obtained from cone-beam computed tomography (CBMercuRay{sup TM}) data and to measure the hard tissue density based on the Hounsfield scale on dental head phantom. CT Scanner Phantom (AAPM) equipped with CT Number Insert consists of five cylindrical pins of materials with different densities and teflon ring was scanned by using the CBMercuRay{sup TM} (Hitachi, Tokyo, Japan) volume scanner. The raw data were converted into DICOM format and the HU of different areas of CT number insert measured by using CBWorks{sup TM}. Linear regression analysis and Student t-test were performed statistically. There was no significant difference (P>0.54) between real densities and measured densities. A linear regression was performed using the density, {rho} (g cm{sup -3}), as the dependent variable in terms of the HU (H). The regression equation obtained was {rho}=0.00072 H-0.01588 with an R2 value of 0.9968. Density values based on the Hounsfield scale was 1697.1 {+-} 24.9 HU in cortical bone, 526.5 {+-} 44.4 HU in trabecular bone, 2639.1 {+-} 48.7 HU in enamel, 1246.1 {+-} 39.4 HU in dentin of dental head phantom. CBCT provides an effective option for determination of material density expressed as Hounsfield Units.

  12. All Road Density (18km)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Density (km / km^2) of all roads in the western United States. Dataset was developed to generalize the 2000 US Census TIGER/Line Roads layer to a density within 18km...

  13. Corrective Action Investigation Plan for Corrective Action Unit 545: Dumps, Waste Disposal Sites, and Buried Radioactive Materials Nevada Test Site, Nevada, Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    Wickline, Alfred

    2007-06-01

    Corrective Action Unit 545, Dumps, Waste Disposal Sites, and Buried Radioactive Materials, consists of seven inactive sites located in the Yucca Flat area and one inactive site in the Pahute Mesa area. The eight CAU 545 sites consist of craters used for mud disposal, surface or buried waste disposed within craters or potential crater areas, and sites where surface or buried waste was disposed. The CAU 545 sites were used to support nuclear testing conducted in the Yucca Flat area during the 1950s through the early 1990s, and in Area 20 in the mid-1970s. This Corrective Action Investigation Plan has been developed in accordance with the Federal Facility Agreement and Consent Order that was agreed to by the State of Nevada, the U.S. Department of Energy, and the U.S. Department of Defense. Under the Federal Facility Agreement and Consent Order, this Corrective Action Investigation Plan will be submitted to the Nevada Division of Environmental Protection for approval. Fieldwork will be conducted following approval.

  14. Certified Reference Material for Use in (1)H, (31)P, and (19)F Quantitative NMR, Ensuring Traceability to the International System of Units.

    Science.gov (United States)

    Rigger, Romana; Rück, Alexander; Hellriegel, Christine; Sauermoser, Robert; Morf, Fabienne; Breitruck, KathrinBreitruck; Obkircher, Markus

    2017-09-01

    In recent years, quantitative NMR (qNMR) spectroscopy has become one of the most important tools for content determination of organic substances and quantitative evaluation of impurities. Using Certified Reference Materials (CRMs) as internal or external standards, the extensively used qNMR method can be applied for purity determination, including unbroken traceability to the International System of Units (SI). The implementation of qNMR toward new application fields, e.g., metabolomics, environmental analysis, and physiological pathway studies, brings along more complex molecules and systems, thus making use of 1H qNMR challenging. A smart workaround is possible by the use of other NMR active nuclei, namely 31P and 19F. This article presents the development of three classes of qNMR CRMs based on different NMR active nuclei (1H, 31P, and 19F), and the corresponding approaches to establish traceability to the SI through primary CRMs from the National Institute of Standards and Technology and the National Metrology Institute of Japan. These TraceCERT® qNMR CRMs are produced under ISO/IEC 17025 and ISO Guide 34 using high-performance qNMR.

  15. High-Density Magnetic Recording and Integrated Magneto-Optics: Materials and Devices; Symposium Held in San Francisco, California, on April 12-16 1998

    Science.gov (United States)

    1998-04-01

    Veloso1,2, P. P. Freitas1,2, J. Fernandes3, M. Ferreira3 ’instituto de Engenharia de Sistemas e Computadores (INESC), R. Alves Redol 9, 1000 Lisboa...Freitasa’b, T.T. Galväoab, JJ. Sun", V. Soares", A. Klingc’d, M.F. da Silva’, and J.C. Soarescd ’Institute de Engenharia de Sistemas e Computadores (INESC...is remarkable that an amor - phous material that is half hydrogen has a hardness comparable to that of single-crystal silicon. We suggested that the

  16. Density functional investigation of mercury and arsenic adsorption on nitrogen doped graphene decorated with palladium clusters: A promising heavy metal sensing material in farmland

    Science.gov (United States)

    Zhao, Chunjiang; Wu, Huarui

    2017-03-01

    Density functional theory calculations are carried out to study the adsorption of mercury and arsenic on Pdn (n = 1-6) supported on pyridine-like nitrogen doped graphene (PNG). Owing to the promising sensitivity in trace amounts of atoms or molecules, PNG can be acted as micro-sensor for sensing heavy metals in agriculture soils. Through the analyses of structural and electronic properties of pristine PNG and Pd atom decorated PNG, we find that the most favorable adsorption site for Pd atom is the vacancy site. The analyses of structural and electronic properties reveal that the Pd atom or clusters can enhance the reactivity for Hg and AsH3 adsorption on PNG. The adsorption ability of Hg on Pdn decorated PNG is found to be related to the d-band center (εd) of the Pdn, in which the closer εd of Pdn to the Fermi level, the higher adsorption strength for Hg on Pdn decorated PNG. Moreover, the charge transfer between Pdn and arsenic may constitute arsenic adsorption on Pdn decorated PNG. Further design of highly efficient carbon based sorbents for heavy metals removal should be focused on tailoring εd of adsorbed metals.

  17. Influence of flavour absorption by food-packaging materials (low-density polyethylene, polycarbonate and polyethylene terephthalate) on taste perception of a model solution and orange juice.

    Science.gov (United States)

    Van Willige, R W G; Linssen, J P H; Legger-Huysman, A; Voragen, A G J

    2003-01-01

    The influence of flavour absorption by low-density polyethylene (LDPE), polycarbonate (PC) and polyethylene terephthalate (PET) on taste perception of a model solution containing seven flavour compounds and orange juice in glass bottles was studied with and without pieces of the respective plastic films after dark storage at 20 degrees C. Owing to absorption, the amount of flavour compounds in the model solution exposed to LDPE decreased substantially. From the model flavour solution valencene was almost completely absorbed by LDPE, followed to a lesser extent by decanal, hexyl acetate, octanal and nonanone. Less flavour compounds were absorbed from the model solution by PC and PET. In contrast to LDPE, valencene was absorbed in the lowest amounts and decanal in the highest. Limonene was readily absorbed from orange juice by LDPE, while myrcene, valencene, pinene and decanal were absorbed in smaller quantities. Only three flavour compounds were absorbed from orange juice by PC and PET in very small amounts: limonene, myrcene and decanal. Although the flavour content between controls and polymer-treated samples differed substantially, the loss of flavour compounds due to absorption by LDPE, PC and PET did not influence taste perception of a model solution and orange juice significantly up to 29 days of dark storage at 20 degrees C as determined by triangular taste panel tests.

  18. Blending of Low-Density Polyethylene and Poly-Lactic Acid with Maleic Anhydride as A Compatibilizer for Better Environmentally Food-Packaging Material

    Science.gov (United States)

    Setiawan, A. H.; Aulia, F.

    2017-05-01

    The common conventional food packaging materialsare using a thin layer plastic or film, which is made of a synthetic polymer, such as Low-Density Poly Ethylene (LDPE). However, the use of these polymers hasan adverse impact on the environment, because the synthetic polymersare difficult to degrade naturally. Poly-Lactic Acid (PLA) is a biodegradable polymer that can be substituted to synthetic polymers. Since LDPE and PLA have a difference in polarity, therefore the first step of research is to graft them with maleic anhydride (MAH) for increasing the properties of its miscibility. The interaction between them is confirmed by FTIR; whereas the environment issueis characterized by the water adsorption and biodegradability. The FTIR spectra indicated that there had been an interaction between LDPE and MAH and LDPE/LDPE-g-MAH/PLA blend. Increasing PLA content in the blend affected to the increasing in their water absorption and biodegradable. Poly-blend with 20% PLA content was the optimum composition for environmentally food packaging.

  19. A Novel Type of Thermal Solar Water Disinfection Unit

    OpenAIRE

    Dietl, Jochen; Engelbart, Hendryk; Sielaff, Axel

    2015-01-01

    A novel type of solar thermal water disinfection unit is presented in this work. The system is safe and easy to use and can be built with basic tools and widely available materials. In the unit, water is disinfected by temperature increase up to the boiling point and output is controlled by the change in density. For employing the change in density to control the water output, a dimensioning procedure is suggested, giving the required height of the water reservoir, the heating section and ...

  20. An In-situ materials analysis particle probe (MAPP) diagnostic to study particle density control and hydrogenic fuel retention in NSTX

    Energy Technology Data Exchange (ETDEWEB)

    Allain, Jean-Paul [Purdue Univ., West Lafayette, IN (United States)

    2014-09-05

    A new materials analysis particle probe (MAPP) was designed, constructed and tested to develop understanding of particle control and hydrogenic fuel retention in lithium-based plasma-facing surfaces in NSTX. The novel feature of MAPP is an in-situ tool to probe the divertor NSTX floor during LLD and lithium-coating shots with subsequent transport to a post-exposure in-vacuo surface analysis chamber to measure D retention. In addition, the implications of a lithiated graphite-dominated plasma-surface environment in NSTX on LLD performance, operation and ultimately hydrogenic pumping and particle control capability are investigated in this proposal. MAPP will be an invaluable tool for erosion/redeposition simulation code validation.

  1. Molecular and Crystal Structure of a New High Energy Density Material: Aminoguanidinium-styphnate, [H2NNHC(NH22]2[C6HO2(NO23

    Directory of Open Access Journals (Sweden)

    Frank T. Edelmann

    2012-01-01

    Full Text Available The title compound [H2NNHC(NH22]2[C6HO2(NO23] (2 was prepared in 85% yield by treatment of sodium styphnate with 2 equivalents of aminoguanidinium nitrate, followed by crystallization from aqueous solution. Compound 2 crystallizes in the triclinic space group Pī with unit cell dimensions a = 6.7224(3 Å, b = 10.7473(4 Å, c = 11.9604(5 Å, α = 113.212(4°, β = 90.579(3°, γ = 99.815(3°, V = 779.68(6 Å3, Z = 2. In the solid state structure of 2, no water of crystallization is present. Bond angles within the aromatic ring of the styphnate anion indicate a significant distortion with larger angles (122.04(18–125.96(18 Å at the carbons bearing the nitro groups, and smaller ones (113.30(17 and 114.07(17 Å at the C-O− carbon atoms. The crystal structure of 2 consists of layers formed by an extensive network of N-H...O hydrogen bonds between NH2 groups of the aminoguanidinium cation and the negatively charged oxygens of the styphnate anion. The layers are again interconnected by N-H...N hydrogen bonds between neighboring aminoguanidinium cations.

  2. MOF-derived crumpled-sheet-assembled perforated carbon cuboids as highly effective cathode active materials for ultra-high energy density Li-ion hybrid electrochemical capacitors (Li-HECs).

    Science.gov (United States)

    Banerjee, Abhik; Upadhyay, Kush Kumar; Puthusseri, Dhanya; Aravindan, Vanchiappan; Madhavi, Srinivasan; Ogale, Satishchandra

    2014-04-21

    Lithium ion hybrid capacitors (Li-HECs) have attracted significant attention for use in next generation advanced energy storage technologies to satisfy the demand of both high power density as well as energy density. Herein we demonstrate the use of very high surface area 3D carbon cuboids synthesized from a metal-organic framework (MOF) as a cathode material with Li₄Ti₅O₁₂ as the anode for high performance Li-HECs. The energy density of the cell is ∼65 W h kg(-1) which is significantly higher than that achievable with commercially available activated carbon (∼36 W h kg(-1)) and a symmetric supercapacitor based on the same MOF-derived carbon (MOF-DC ∼20 W h kg(-1)). The MOF-DC/Li₄Ti₅O₁₂ Li-HEC assembly also shows good cyclic performance with ∼82% of the initial value (∼25 W h kg(-1)) retained after 10,000 galvanostatic cycles under high rate cyclic conditions. This result clearly indicates that MOF-DC is a very promising candidate for future P-HEVs in a Li-HEC configuration.

  3. Fast-Rate Capable Electrode Material with Higher Energy Density than LiFePO4: 4.2V LiVPO4F Synthesized by Scalable Single-Step Solid-State Reaction.

    Science.gov (United States)

    Kim, Minkyung; Lee, Seongsu; Kang, Byoungwoo

    2016-03-01

    Use of compounds that contain fluorine (F) as electrode materials in lithium ion batteries has been considered, but synthesizing single-phase samples of these compounds is a difficult task. Here, it is demonstrated that a simple scalable single-step solid-state process with additional fluorine source can obtain highly pure LiVPO4F. The resulting material with submicron particles achieves very high rate capability ≈100 mAh g(-1) at 60 C-rate (1-min discharge) and even at 200 C-rate (18 s discharge). It retains superior capacity, ≈120 mAh g(-1) at 10 C charge/10 C discharge rate (6-min) for 500 cycles with >95% retention efficiency. Furthermore, LiVPO4F shows low polarization even at high rates leading to higher operating potential >3.45 V (≈3.6 V at 60 C-rate), so it achieves high energy density. It is demonstrated for the first time that highly pure LiVPO4F can achieve high power capability comparable to LiFePO4 and much higher energy density (≈521 Wh g(-1) at 20 C-rate) than LiFePO4 even without nanostructured particles. LiVPO4F can be a real substitute of LiFePO4.

  4. Corrective Action Investigation Plan for Corrective Action Unit 166: Storage Yards and Contaminated Materials, Nevada Test Site, Nevada, Rev. No.: 0

    Energy Technology Data Exchange (ETDEWEB)

    David Strand

    2006-06-01

    Corrective Action Unit 166 is located in Areas 2, 3, 5, and 18 of the Nevada Test Site, which is 65 miles northwest of Las Vegas, Nevada. Corrective Action Unit (CAU) 166 is comprised of the seven Corrective Action Sites (CASs) listed below: (1) 02-42-01, Cond. Release Storage Yd - North; (2) 02-42-02, Cond. Release Storage Yd - South; (3) 02-99-10, D-38 Storage Area; (4) 03-42-01, Conditional Release Storage Yard; (5) 05-19-02, Contaminated Soil and Drum; (6) 18-01-01, Aboveground Storage Tank; and (7) 18-99-03, Wax Piles/Oil Stain. These sites are being investigated because existing information on the nature and extent of potential contamination is insufficient to evaluate and recommend corrective action alternatives. Additional information will be obtained by conducting a corrective action investigation (CAI) before evaluating corrective action alternatives and selecting the appropriate corrective action for each CAS. The results of the field investigation will support a defensible evaluation of viable corrective action alternatives that will be presented in the Corrective Action Decision Document. The sites will be investigated based on the data quality objectives (DQOs) developed on February 28, 2006, by representatives of the Nevada Division of Environmental Protection; U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office; Stoller-Navarro Joint Venture; and Bechtel Nevada. The DQO process was used to identify and define the type, amount, and quality of data needed to develop and evaluate appropriate corrective actions for CAU 166. Appendix A provides a detailed discussion of the DQO methodology and the DQOs specific to each CAS. The scope of the CAI for CAU 166 includes the following activities: (1) Move surface debris and/or materials, as needed, to facilitate sampling. (2) Conduct radiological surveys. (3) Perform field screening. (4) Collect and submit environmental samples for laboratory analysis to determine if

  5. Movimento e inativação do metribuzin em materiais de dois solos, sob diferentes densidades aparentes Movement and inactivation of metribuzin in two soil materials with different bulk densities

    Directory of Open Access Journals (Sweden)

    L.E.F. Fontes

    1980-06-01

    Full Text Available Numa série de ensaios em laboratório e casa-de-vegetação, estudou-se a mobilidade e a inativação do herbicida metribuzin em materiais de um Latossolo e de um Podzólico representativos de duas regiões do Estado de Minas Gerais, em função de diferentes densidades aparentes. Ensaios biológicos foram utilizados para medir a inativação e a mobilidade do metribuzin nos diferentes solos e densidades. A densidade aparente alterou de forma pronunciada a quantidade de herbicida lixiviado através das colunas dos materiais dos solos estudados. Quanto maior a densidade, menor a quantidade de herbicida lixiviado. A quantidade de herbicida que permaneceu biologicamente ativo ao longo da coluna foi diretamente relacionada com a densidade, em cada solo. A mobilidade do metribuzin no material do Latossolo foi maior que no de Podzólico, em consequência de maior atividade coloidal deste.The leaching and inactivation of metribuzin were studied with materials of two mineral soilsat different bulk densities. Plastic tubing of' 7.25 cm diameter and 10 cm height were filled up with different amounts of soil to get different bulk densities. One kg/ha of a.i. of metribuzin placed on the surface are a of the column was le ached through these soil colums using 250 ml of water. The cotyledon disk bioassay method was used to detect the metribuzin leachet. The biological active metribuzin in the soil colunn at different depths, and the inativation abil ity of the soils were determined using the assay with cucumber (Cucumis sativus L. as test-plant. The increase of bulk density reduced the leaching and enhanced the biologically active metribuzin in the soil column. Metribuzin was more mobil in the Red -yellow Lato ssol and more inactivated in the Red-yellow Podzolic soils.

  6. Energy in density gradient

    CERN Document Server

    Vranjes, J

    2015-01-01

    Inhomogeneous plasmas and fluids contain energy stored in inhomogeneity and they naturally tend to relax into lower energy states by developing instabilities or by diffusion. But the actual amount of energy in such inhomogeneities has remained unknown. In the present work the amount of energy stored in a density gradient is calculated for several specific density profiles in a cylindric configuration. This is of practical importance for drift wave instability in various plasmas, and in particular in its application in models dealing with the heating of solar corona because the instability is accompanied with stochastic heating, so the energy contained in inhomogeneity is effectively transformed into heat. It is shown that even for a rather moderate increase of the density at the axis in magnetic structures in the corona by a factor 1.5 or 3, the amount of excess energy per unit volume stored in such a density gradient becomes several orders of magnitude greater than the amount of total energy losses per unit ...

  7. Energy in density gradient

    Energy Technology Data Exchange (ETDEWEB)

    Vranjes, J., E-mail: jvranjes@yahoo.com [Instituto de Astrofísica de Canarias, 38205 La Laguna, Tenerife (Spain); Departamento de Astrofísica, Universidad de La Laguna, 38205 La Laguna, Tenerife (Spain); Kono, M., E-mail: kono@fps.chuo-u.ac.jp [Faculty of Policy Studies, Chuo University, Tokyo (Japan)

    2015-01-15

    Inhomogeneous plasmas and fluids contain energy stored in inhomogeneity and they naturally tend to relax into lower energy states by developing instabilities or by diffusion. But the actual amount of energy in such inhomogeneities has remained unknown. In the present work, the amount of energy stored in a density gradient is calculated for several specific density profiles in a cylindrical configuration. This is of practical importance for drift wave instability in various plasmas, and, in particular, in its application in models dealing with the heating of solar corona because the instability is accompanied with stochastic heating, so the energy contained in inhomogeneity is effectively transformed into heat. It is shown that even for a rather moderate increase of the density at the axis in magnetic structures in the corona by a factor 1.5 or 3, the amount of excess energy per unit volume stored in such a density gradient becomes several orders of magnitude greater than the amount of total energy losses per unit volume (per second) in quiet regions in the corona. Consequently, within the life-time of a magnetic structure such energy losses can easily be compensated by the stochastic drift wave heating.

  8. Corrective Action Decision Document/Closure Report for Corrective Action Unit 529: Area 25 Contaminated Materials, Nevada Test Site, Nevada, Rev. No.: 1

    Energy Technology Data Exchange (ETDEWEB)

    Robert F. Boehlecke

    2004-11-01

    This Corrective Action Decision Document (CADD)/Closure Report (CR) has been prepared for Corrective Action Unit (CAU) 529, Area 25 Contaminated Materials, Nevada Test Site (NTS), Nevada, in accordance with the ''Federal Facility Agreement and Consent Order'' (FFACO) that was agreed to by the State of Nevada, U.S. Department of Energy (DOE), and the U.S. Department of Defense (FFACO, 1996). The NTS is approximately 65 miles (mi) northwest of Las Vegas, Nevada (Figure 1-1). Corrective Action Site (CAS) 25-23-17, Contaminated Wash, is the only CAS in CAU 529 and is located in Area 25 of the NTS, in Nye County, Nevada (Figure 1-2). Corrective Action Site 25-23-17, Contaminated Wash, was divided into nine parcels because of the large area impacted by past operations and the complexity of the source areas. The CAS was subdivided into separate parcels based on separate and distinct releases as determined and approved in the Data Quality Objectives (DQO) process and Corrective Action Investigation Plan (CAIP). Table 1-1 summarizes the suspected sources for the nine parcels. Corrective Action Site 25-23-17 is comprised of the following nine parcels: (1) Parcel A, Kiwi Transient Nuclear Test (TNT) 16,000-foot (ft) Arc Area (Kiwi TNT); (2) Parcel B, Phoebus 1A Test 8,000-ft Arc Area (Phoebus); (3) Parcel C, Topopah Wash at Test Cell C (TCC); (4) Parcel D, Buried Contaminated Soil Area (BCSA) l; (5) Parcel E, BCSA 2; (6) Parcel F, Borrow Pit Burial Site (BPBS); (7) Parcel G, Drain/Outfall Discharges; (8) Parcel H, Contaminated Soil Storage Area (CSSA); and (9) Parcel J, Main Stream/Drainage Channels.

  9. Effectiveness of the International Phytosanitary Standard ISPM No. 15 on reducing wood borer infestation rates in wood packaging material entering the United States.

    Directory of Open Access Journals (Sweden)

    Robert A Haack

    Full Text Available Numerous bark- and wood-infesting insects have been introduced to new countries by international trade where some have caused severe environmental and economic damage. Wood packaging material (WPM, such as pallets, is one of the high risk pathways for the introduction of wood pests. International recognition of this risk resulted in adoption of International Standards for Phytosanitary Measures No. 15 (ISPM15 in 2002, which provides treatment standards for WPM used in international trade. ISPM15 was originally developed by members of the International Plant Protection Convention to "practically eliminate" the risk of international transport of most bark and wood pests via WPM. The United States (US implemented ISPM15 in three phases during 2005-2006. We compared pest interception rates of WPM inspected at US ports before and after US implementation of ISPM15 using the US Department of Agriculture AQIM (Agriculture Quarantine Inspection Monitoring database. Analyses of records from 2003-2009 indicated that WPM infestation rates declined 36-52% following ISPM15 implementation, with results varying in statistical significance depending on the selected starting parameters. Power analyses of the AQIM data indicated there was at least a 95% chance of detecting a statistically significant reduction in infestation rates if they dropped by 90% post-ISPM15, but the probability fell as the impact of ISPM15 lessened. We discuss several factors that could have reduced the apparent impact of ISPM15 on lowering WPM infestation levels, and suggest ways that ISPM15 could be improved. The paucity of international interception data impeded our ability to conduct more thorough analyses of the impact of ISPM15, and demonstrates the need for well-planned sampling programs before and after implementation of major phytosanitary policies so that their effectiveness can be assessed. We also present summary data for bark- and wood-boring insects intercepted on WPM at US

  10. Effectiveness of the International Phytosanitary Standard ISPM No. 15 on reducing wood borer infestation rates in wood packaging material entering the United States.

    Science.gov (United States)

    Haack, Robert A; Britton, Kerry O; Brockerhoff, Eckehard G; Cavey, Joseph F; Garrett, Lynn J; Kimberley, Mark; Lowenstein, Frank; Nuding, Amelia; Olson, Lars J; Turner, James; Vasilaky, Kathryn N

    2014-01-01

    Numerous bark- and wood-infesting insects have been introduced to new countries by international trade where some have caused severe environmental and economic damage. Wood packaging material (WPM), such as pallets, is one of the high risk pathways for the introduction of wood pests. International recognition of this risk resulted in adoption of International Standards for Phytosanitary Measures No. 15 (ISPM15) in 2002, which provides treatment standards for WPM used in international trade. ISPM15 was originally developed by members of the International Plant Protection Convention to "practically eliminate" the risk of international transport of most bark and wood pests via WPM. The United States (US) implemented ISPM15 in three phases during 2005-2006. We compared pest interception rates of WPM inspected at US ports before and after US implementation of ISPM15 using the US Department of Agriculture AQIM (Agriculture Quarantine Inspection Monitoring) database. Analyses of records from 2003-2009 indicated that WPM infestation rates declined 36-52% following ISPM15 implementation, with results varying in statistical significance depending on the selected starting parameters. Power analyses of the AQIM data indicated there was at least a 95% chance of detecting a statistically significant reduction in infestation rates if they dropped by 90% post-ISPM15, but the probability fell as the impact of ISPM15 lessened. We discuss several factors that could have reduced the apparent impact of ISPM15 on lowering WPM infestation levels, and suggest ways that ISPM15 could be improved. The paucity of international interception data impeded our ability to conduct more thorough analyses of the impact of ISPM15, and demonstrates the need for well-planned sampling programs before and after implementation of major phytosanitary policies so that their effectiveness can be assessed. We also present summary data for bark- and wood-boring insects intercepted on WPM at US ports during 1984-2008.

  11. History and modern applications of nano-composite materials carrying GA/cm2 current density due to a Bose-Einstein Condensate at room temperature produced by Focused Electron Beam Induced Processing for many extraordinary novel technical applications

    Science.gov (United States)

    Koops, Hans W. P.

    2015-12-01

    The discovery of Focused Electron Beam Induced Processing and early applications of this technology led to the possible use of a novel nanogranular material “Koops-GranMat®” using Pt/C and Au/C material. which carries at room temperature a current density > 50 times the current density which high TC superconductors can carry. The explanation for the characteristics of this novel material is given. This fact allows producing novel products for many applications using Dual Beam system having a gas supply and X.Y.T stream data programming and not using GDSII layout pattern control software. Novel products are possible for energy transportation. -distribution.-switching, photon-detection above 65 meV energy for very efficient energy harvesting, for bright field emission electron sources used for vacuum electronic devices like amplifiers for HF electronics, micro-tubes, 30 GHz to 6 THz switching amplifiers with signal to noise ratio >10(!), THz power sources up to 1 Watt, in combination with miniaturized vacuum pumps, vacuum gauges, IR to THz detectors, EUV- and X-Ray sources. Since focusing electron beam induced deposition works also at low energy, selfcloning multibeam-production machines for field emitter lamps, displays, multi-beam - lithography, - imaging, and - inspection, energy harvesting, and power distribution with switches controlling field-emitter arrays for KA of currents but with < 100 V switching voltage are possible. Finally the replacement of HTC superconductors and its applications by the Koops-GranMat® having Koops-Pairs at room temperature will allow the investigation devices similar to Josephson Junctions and its applications now called QUIDART (Quantum interference devices at Room Temperature). All these possibilities will support a revolution in the optical, electric, power, and electronic technology.

  12. Corrective Action Decision Document for Corrective Action Unit 168: Area 25 and 26 Contaminated Materials and Waste Dumps, Nevada Test Site, Nevada, Rev. No.: 2 with Errata Sheet

    Energy Technology Data Exchange (ETDEWEB)

    Wickline, Alfred

    2006-12-01

    This Corrective Action Decision Document has been prepared for Corrective Action Unit (CAU) 168: Area 25 and 26, Contaminated Materials and Waste Dumps, Nevada Test Site, Nevada. The purpose of this Corrective Action Decision Document is to identify and provide a rationale for the selection of a recommended corrective action alternative for each corrective action site (CAS) within CAU 168. The corrective action investigation (CAI) was conducted in accordance with the ''Corrective Action Investigation Plan for Corrective Action Unit 168: Area 25 and 26, Contaminated Materials and Waste Dumps, Nevada Test Site, Nevada'', as developed under the ''Federal Facility Agreement and Consent Order'' (1996). Corrective Action Unit 168 is located in Areas 25 and 26 of the Nevada Test Site, Nevada and is comprised of the following 12 CASs: CAS 25-16-01, Construction Waste Pile; CAS 25-16-03, MX Construction Landfill; CAS 25-19-02, Waste Disposal Site; CAS 25-23-02, Radioactive Storage RR Cars; CAS 25-23-13, ETL - Lab Radioactive Contamination; CAS 25-23-18, Radioactive Material Storage; CAS 25-34-01, NRDS Contaminated Bunker; CAS 25-34-02, NRDS Contaminated Bunker; CAS 25-99-16, USW G3; CAS 26-08-01, Waste Dump/Burn Pit; CAS 26-17-01, Pluto Waste Holding Area; and CAS 26-19-02, Contaminated Waste Dump No.2. Analytes detected during the CAI were evaluated against preliminary action levels (PALs) to determine contaminants of concern (COCs) for CASs within CAU 168. Radiological measurements of railroad cars and test equipment were compared to unrestricted (free) release criteria. Assessment of the data generated from the CAI activities revealed the following: (1) Corrective Action Site 25-16-01 contains hydrocarbon-contaminated soil at concentrations exceeding the PAL. The contamination is at discrete locations associated with asphalt debris. (2) No COCs were identified at CAS 25-16-03. Buried construction waste is present in at least two

  13. Investigation of The regularities of the process and development of method of management of technological line operation within the process of mass raw mate-rials supply in terms of dynamics of inbound traffic of unit trains

    Directory of Open Access Journals (Sweden)

    Катерина Ігорівна Сізова

    2015-03-01

    Full Text Available Large-scale sinter plants at metallurgical enterprises incorporate highly productive transport-and-handling complexes (THC that receive and process mass iron-bearing raw materials. Such THCs as a rule include unloading facilities and freight railway station. The central part of the THC is a technological line that carries out operations of reception and unloading of unit trains with raw materials. The technological line consists of transport and freight modules. The latter plays a leading role and, in its turn, consists of rotary car dumpers and conveyor belts. This module represents a determinate system that carries out preparation and unloading operations. Its processing capacity is set in accordance with manufacturing capacity of the sinter plant. The research has shown that in existing operating conditions, which is characterized by “arrhythmia” of interaction between external transport operation and production, technological line of THC functions inefficiently. Thus, it secures just 18-20 % of instances of processing of inbound unit trains within set standard time. It was determined that duration of the cycle of processing of inbound unit train can play a role of regulator, under stochastic characteristics of intervals between inbound unit trains with raw materials on the one hand, and determined unloading system on the other hand. That is why evaluation of interdependence between these factors allows determination of duration of cycle of processing of inbound unit trains. Basing on the results of the study, the method of logistical management of the processing of inbound unit trains was offered. At the same time, real duration of processing of inbound unit train is taken as the regulated value. The regulation process implies regular evaluation and comparison of these values, and, taking into account different disturbances, decision-making concerning adaptation of functioning of technological line. According to the offered principles

  14. Corrective Action Decision Document/Closure Report for Corrective Action Unit 545: Dumps, Waste Disposal Sites, and Buried Radioactive Materials Nevada Test Site, Nevada, Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    Alfred Wickline

    2008-04-01

    This Corrective Action Decision Document (CADD)/Closure Report (CR) has been prepared for Corrective Action Unit (CAU) 545, Dumps, Waste Disposal Sites, and Buried Radioactive Materials, in Areas 2, 3, 9, and 20 of the Nevada Test Site, Nevada, in accordance with the Federal Facility Agreement and Consent Order that was agreed to by the State of Nevada; U.S. Department of Energy (DOE), Environmental Management; U.S. Department of Defense; and DOE, Legacy Management (1996, as amended February 2008). Corrective Action Unit 545 is comprised of the following eight Corrective Action Sites (CASs): • 02-09-01, Mud Disposal Area • 03-08-03, Mud Disposal Site • 03-17-01, Waste Consolidation Site 3B • 03-23-02, Waste Disposal Site • 03-23-05, Europium Disposal Site • 03-99-14, Radioactive Material Disposal Area • 09-23-02, U-9y Drilling Mud Disposal Crater • 20-19-01, Waste Disposal Site While all eight CASs are addressed in this CADD/CR, sufficient information was available for the following three CASs; therefore, a field investigation was not conducted at these sites: • For CAS 03-08-03, though the potential for subsidence of the craters was judged to be extremely unlikely, the data quality objective (DQO) meeting participants agreed that sufficient information existed about disposal and releases at the site and that a corrective action of close in place with a use restriction is recommended. Sampling in the craters was not considered necessary. • For CAS 03-23-02, there were no potential releases of hazardous or radioactive contaminants identified. Therefore, the Corrective Action Investigation Plan for CAU 545 concluded that: “Sufficient information exists to conclude that this CAS does not exist as originally identified. Therefore, there is no environmental concern associated with CAS 03-23-02.” This CAS is closed with no further action. • For CAS 03-23-05, existing information about the two buried sources and lead pig was considered to be

  15. Superfund record of decision (EPA Region 5): Feed Materials Production Center, (USDOE), Operable Unit 1, Fernald, Hamilton and Butler Counties, OH, March 1, 1995. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-02-01

    The decision document presents the selected remedial action for Operable Unit 1 of the FEMP site in Hamilton and Butler Counties, Ohio. Operable Unit 1 consists of Waste Pits 1 through 6, the Burn Pit, the Clearwell, and associated environmental media (excluding groundwater).

  16. Studies of Phase Change Materials and a Latent Heat Storage Unit Used for a Natural Circulation Cooling/Latent Heat Storage System

    Science.gov (United States)

    Sakitani, Katsumi; Honda, Hiroshi

    Experimental and theoretical studies were made of the heat transfer characteristics of a latent heat storage unit used for a natural circulation cooling /latent heat storage system. Heating and cooling curves of the latent heat storage unit undergoing solid-liquid phase change of a PCM (lauric acid) was obtained by using anatural circulation loop of R22 which consisted of an electrically heated evaporater, a water cooled condenser and the latent heat storage unit. The latent heat storage unit showed a heat transfer performance which was high enough for practical use. An approximate theoretical analysis was conducted to investigate transient behavior of the latent heat storage unit. Predictions of the refrigerant and outer surface temperatures during the melting process were in fair agreement with the experimental data, whereas that of the refrigerant temperature during the solidification process was considerably lower than the measurement.

  17. Preparation, thermal and flammability properties of a novel form-stable phase change materials based on high density polyethylene/poly(ethylene-co-vinyl acetate)/organophilic montmorillonite nanocomposites/paraffin compounds

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Yibing [State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230027 (China); Key Laboratory of Eco-textiles, Ministry of Education, Jiangnan University, Wuxi, Jiangsu 214122 (China); Song, Lei; He, Qingliang; Yang, Dandan; Hu, Yuan [State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230027 (China)

    2008-08-15

    The paraffin is one of important thermal energy storage materials with many desirable characteristics (i.e., high heat of fusion, varied phase change temperature, negligible supercooling, self-nucleating, no phase segregation and cheap, etc.), but has low thermal stability and flammable. Hence, a novel form-stable phase change materials (PCM) based on high density polyethylene (HDPE)/poly(ethylene-co-vinyl acetate) (EVA)/organophilic montmorillonite (OMT) nanocomposites and paraffin are prepared by twin-screw extruder technique. The structures of the HDPE-EVA/OMT nanocomposites and the form-stable PCM are evidenced by the X-ray diffraction (XRD), transmission electronic microscopy (TEM) and scanning electronic microscope (SEM). The results of XRD and TEM show that the HDPE-EVA/OMT nanocomposites form the ordered intercalated nanomorphology. The form-stable PCM consists of the paraffin, which acts as a dispersed phase change material and the HDPE-EVA/OMT nanocomposites, which acts as the supporting material. The paraffin disperses in the three-dimensional net structure formed by HDPE-EVA/OMT nanocomposites. The thermal stability, latent heat and flammability properties are characterized by thermogravimetry analysis (TGA), dynamic Fourier-transform infrared (FTIR), differential scanning calorimeter (DSC) and cone calorimeter, respectively. The TGA and dynamic FTIR analyses indicate that the incorporation of suitable amount of OMT into the form-stable PCM increase the thermal stability. The DSC results show that the latent heat of the form-stable PCM has a certain degree decrease. The cone calorimeter shows that the heat release rate (HRR) has remarkably decreases with loading of OMT in the form-stable PCM, contributing to the improved flammability properties. (author)

  18. Preparation, thermal and flammability properties of a novel form-stable phase change materials based on high density polyethylene/poly(ethylene-co-vinyl acetate)/organophilic montmorillonite nanocomposites/paraffin compounds

    Energy Technology Data Exchange (ETDEWEB)

    Cai Yibing [State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230027 (China); Key Laboratory of Eco-textiles, Ministry of Education, Jiangnan University, Wuxi, Jiangsu 214122 (China); Song Lei [State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230027 (China)], E-mail: leisong@ustc.edu.cn; He Qingliang; Yang Dandan; Hu Yuan [State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230027 (China)

    2008-08-15

    The paraffin is one of important thermal energy storage materials with many desirable characteristics (i.e., high heat of fusion, varied phase change temperature, negligible supercooling, self-nucleating, no phase segregation and cheap, etc.), but has low thermal stability and flammable. Hence, a novel form-stable phase change materials (PCM) based on high density polyethylene (HDPE)/poly(ethylene-co-vinyl acetate) (EVA)/organophilic montmorillonite (OMT) nanocomposites and paraffin are prepared by twin-screw extruder technique. The structures of the HDPE-EVA/OMT nanocomposites and the form-stable PCM are evidenced by the X-ray diffraction (XRD), transmission electronic microscopy (TEM) and scanning electronic microscope (SEM). The results of XRD and TEM show that the HDPE-EVA/OMT nanocomposites form the ordered intercalated nanomorphology. The form-stable PCM consists of the paraffin, which acts as a dispersed phase change material and the HDPE-EVA/OMT nanocomposites, which acts as the supporting material. The paraffin disperses in the three-dimensional net structure formed by HDPE-EVA/OMT nanocomposites. The thermal stability, latent heat and flammability properties are characterized by thermogravimetry analysis (TGA), dynamic Fourier-transform infrared (FTIR), differential scanning calorimeter (DSC) and cone calorimeter, respectively. The TGA and dynamic FTIR analyses indicate that the incorporation of suitable amount of OMT into the form-stable PCM increase the thermal stability. The DSC results show that the latent heat of the form-stable PCM has a certain degree decrease. The cone calorimeter shows that the heat release rate (HRR) has remarkably decreases with loading of OMT in the form-stable PCM, contributing to the improved flammability properties.

  19. Synthesis, characterization, and energetic properties of 6-amino-tetrazolo[1,5-b]-1,2,4,5-tetrazine-7-N-oxide: a nitrogen-rich material with high density.

    Science.gov (United States)

    Wei, Hao; Zhang, Jiaheng; Shreeve, Jean'ne M

    2015-05-01

    The synthesis and energetic properties of a novel N-oxide high-nitrogen compound, 6-amino-tetrazolo[1,5-b]-1,2,4,5-tetrazine-7-N-oxide, are described. Resulting from the N-oxide and fused rings system, this molecule exhibits high density, excellent detonation properties, and acceptable impact and friction sensitivities, which suggests potential applications as an energetic material. Compared to known high-nitrogen compounds, such as 3,6-diazido-1,2,4,5-tetrazine (DiAT), 2,4,6-tri(azido)-1,3,5-triazine (TAT), and 4,4',6,6'-tetra(azido)azo-1,3,5-triazine (TAAT), a marked performance and stability increase is seen. This supports the superior qualities of this new compound and the advantage of design strategy.

  20. Ⅲ-Ⅴ family of semiconductor materials photonic crystal state density characteristics%Ⅲ-Ⅴ族半导体材料组成光子晶体能态密度特性

    Institute of Scientific and Technical Information of China (English)

    陈士芹

    2012-01-01

    Application of the plane wave expansion method research □-□ family of semiconductor materials photonic crystal can state density, get filled with a radius of grid work rate f the variations between the corresponding state density distribution, when f = 0.2 a normalized when frequency biggest photonic band gap. Through the comparison for semiconductor compound material, AlP AIAs,AISb GaP and a 2 d square photonic crystals that has a wide GaP of the photon belt, with filling rate increase photonic crystal increase. The results of photonic crystal devices to provide the theory basis.%应用平面波展开法研究Ⅲ-Ⅴ族半导体材料组成光子晶体能态密度特性,得到填充率f随品格半径a之间的变化对应的能态密度分布,当f=0.2a时归一化频率存在最大光子带隙。通过比较化合物半导体材料为AIP、AJAs、AISb和GaP构成二维方形光子晶体得出GaP有较宽的光子禁带,随着填充率的增加光子晶体带隙增加。研究结果为光子晶体器件的研究提供理论依据。

  1. Tuning of the vinyl groups' spacing at surface of modified silica in preparation of high density imprinted layer-coated silica nanoparticles: a dispersive solid-phase extraction materials for chlorpyrifos.

    Science.gov (United States)

    Lu, Qing; Chen, Xuemei; Nie, Li; Luo, Jing; Jiang, Huijun; Chen, Lina; Hu, Qin; Du, Shuhu; Zhang, Zhongping

    2010-05-15

    This paper reports the preparation of high density imprinted layer-coated silica nanoparticles toward selective recognition and fast enrichment of chlorpyrifos (CP) from complicated matrices. The molecularly imprinted polymers (MIPs) were successfully coated at the surface of modified silica through using the chemical immovable vinyl groups at the nanoparticles' surface, followed by the graft copolymerization of methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) in the presence of templates CP. It has been demonstrated that the space of end vinyl groups at the surface of silica can be controlled by changing the condition of chemical modification, regulating the thickness of imprinted shells and the density of efficient imprinted sites. After removal of templates by solvent extraction, the recognition sites of CP were created in the polymer coating layer. The CP-imprinted nanoparticles exhibited high recognition selectivity and binding affinity to CP analyte. When the CP-imprinted nanoparticles were used as dispersive solid-phase extraction (dSPE) materials, the high recovery yields of 76.1-93.5% from various spiked samples with only 1microg/mL analyte were achieved by one-step extraction. These results reported herein provide the possibility for the separation and enrichment of CP from complicated matrices by the molecular imprinting modification at the surface of common silica nanoparticles.

  2. Propulsion materials

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-01-01

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

  3. Scientific Opinion on the safety evaluation of the process “Schoeller Arca Systems”, used to recycle polypropylene and high-density polyethylene crates for use as food contact material

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF

    2013-04-01

    Full Text Available This scientific opinion of the EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids deals with the safety evaluation of the recycling process “Schoeller Arca Systems”, EC register number RECYC075. The process recycles damaged food contact re-usable polypropylene (PP and high-density polyethylene (HDPE crates which have been used in a closed and controlled product loop into new recycled crates. Through this process, damaged crates are firstly ground into flakes which are further blended with virgin PP or HDPE or used at 100 % to manufacture new recycled PP and HDPE crates. The CEF Panel concluded that the input of the process “Schoeller Arca Systems” originates from a product loop which is in a closed and controlled chain ensuring that only materials and articles which have been intended for food contact are used and that any contamination can be ruled out when run under the conditions described by the applicant. The Panel considered that the repeated grinding and injection moulding of PP and HDPE crates, which is part of the recycling process, under conditions described by the applicant, is not of safety concern. Therefore the recycling process “Schoeller Arca Systems” is able to produce recycled PP and HDPE suitable for manufacturing crates intended to be used in contact at room temperature or below with meat, whole fruits and vegetables as requested by the applicant.

  4. Physico-chemical characterization, density functional theory (DFT) studies and Hirshfeld surface analysis of a new organic optical material: 1H-benzo[d]imidazol-3-ium-2,4,6-trinitrobenzene-1,3 bis(olate)

    Science.gov (United States)

    Dhamodharan, P.; Sathya, K.; Dhandapani, M.

    2017-10-01

    A novel organic crystal, 1H-benzo[d]imidazol-3-ium-2,4,6-trinitrobenzene-1,3 bis(olate) (BITB), was synthesized. Single crystals of BITB were harvested by solution growth-slow evaporation technique. 1H and 13C NMR spectroscopic techniques were utilized to confirm the presence of various types of carbons and protons in BITB. Single crystal XRD confirms that BITB crystallizes in monoclinic system with a space group of P21/n. The suitability of this material for optical applications was assessed by optical absorption, transmittance, reflectance and refractive index spectroscopic techniques. Gaussian 09 program at B3LYP/6-311++G(d,p) level of basis set as used for the optimization of molecular structure of BITB. Greater first order hyperpolarizability value of BITB is due to intensive hydrogen bond network in the crystal. The value is 15 times greater than that of Urea, a reference standard. Computation of frontier molecular orbitals and electrostatic potential surface helped to understand the electron density and reactive sites in BITB. The material was thermally stable up to 220 °C. Hirshfeld surface analysis was performed to quantify the covalent and non covalent interactions.

  5. Amorphous LiCoO2sbnd Li2SO4 active materials: Potential positive electrodes for bulk-type all-oxide solid-state lithium batteries with high energy density

    Science.gov (United States)

    Nagao, Kenji; Hayashi, Akitoshi; Deguchi, Minako; Tsukasaki, Hirofumi; Mori, Shigeo; Tatsumisago, Masahiro

    2017-04-01

    Newly amorphous Li2-x/100Cox/100S1-x/100O4-x/50 (xLiCoO2·(100-x)Li2SO4 (mol%)) positive electrode active materials are synthesized using mechanochemical techniques. SEM observation indicates that average radii of the Li1.2Co0.8S0.2O2.4 (80LiCoO2·20Li2SO4 (mol%)) particles are about 3 μm. HR-TEM images indicate that the particles comprise nano-crystalline and amorphous phases. The crystalline phase is attributable to cubic LiCoO2 phase. These active materials exhibit a high electronic conductivity of around 10-5-10-1 S cm-1 and an ionic conductivity of around 10-7-10-6 S cm-1 at room temperature. Bulk-type all-oxide solid-state cells (Lisbnd In alloy/Li3BO3-based glass-ceramic electrolyte/amorphous Li2-x/100Cox/100S1-x/100O4-x/50) are fabricated by pressing at room temperature without high temperature sintering. Although the cell with the milled LiCoO2 shows no capacity, the cell using the Li1.2Co0.8S0.2O2.4 electrode with no conductive components (ca. 150 μm thickness) operates as a secondary battery at 100 °C, with an average discharge potential of 3.3 V (vs. Li+/Li) and discharge capacity of 163 mAh g-1. A positive electrode with large amounts of active materials is suitable for achieving high energy density in all-solid-state batteries. These newly synthesized amorphous Li2-x/100Cox/100S1-x/100O4-x/50 electrodes with ionic and electronic conductivities and good processability meet that demand.

  6. 不同半导体材料构成光子晶体在太赫兹波段能态密度特性%State Density Properties of Photonic Crystal Composited by Different Semiconductor Material in Terahertz Band

    Institute of Scientific and Technical Information of China (English)

    邴丕彬; 闫昕

    2012-01-01

    Based on the plane wave expansion method research Ⅳ, Ⅲ-Ⅴ and Ⅱ- Ⅵ semiconductor material composition family 2d triangle photonic crystal lattice terahertz band state density of characteristics, numerical simulation to get Ⅳ family in filling SiC rate f = 0. 8 form 0. 037 THz band gap width, Ⅱ-Ⅵ ZnO family in filling rate f = 0. 73 form 0. 0417 THz band gap width form, the filler rate case Ⅲ-Ⅴ race semiconductor material form 0.027 THz band gap width, more data Ⅱ-Ⅵ race semiconductor material form more wide band gap, the result is too Hertz photonic crystal devices to provide the theoretical basis for development.%基于平面波展开法研究Ⅳ、Ⅲ-Ⅴ和Ⅱ-Ⅵ族半导体材料构成二维三角晶格光子晶体在太赫兹波段的能态密度特性,数值模拟得到Ⅳ族SiC在填充率f=0.8时形成0.037 THz带隙宽度,Ⅱ-Ⅵ族ZnO在填充率f=0.73时形成0.0417 THz带隙宽度,不同填充率情况下Ⅲ-Ⅴ族半导体材料形成0.027 THz带隙宽度,比较数据Ⅱ-Ⅵ族半导体材料形成较宽的带隙,研究结果为太赫兹光子晶体器件的开发提供了理论依据.

  7. Effective Thermal Conductivity Analysis of Xonotlite-aerogel Composite Insulation Material

    Institute of Scientific and Technical Information of China (English)

    Gaosheng WEI; Xinxin ZHANG; Fan YU

    2009-01-01

    A 3-dimensional unit cell model is developed for analyzing effective thermal conductivity of xonotlite-aerogel composite insulation material based on its microstructure features. Effective thermal conductivity comparisons between xonotlite-type calcium silicate and aerogel as well as xonotlite-aerogei composite insulation material are presented. It is shown that the density of xonotlite-type calcium silicate is the key factor affecting the effective thermal conductivity of xonotlite-aerogel composite insulation material, and the density of aerogel has tittle in-fluence. The effective thermal conductivity can be lowered greatly by composite of the two materials at an ele-vated temperature.

  8. The Identification and Role of School Libraries that Function as Instructional Materials Centers and Implications for Library Education in the United States.

    Science.gov (United States)

    Lohrer, Alice

    In 1961, the American Association of School Librarians requested a status study to identify elementary, junior and senior high school library programs which serve as instructional materials centers (IMC). An IMC library provides all types of instructional materials and services for teachers and pupils. Initial findings, which were tabulated after…

  9. Influence of composite restorative materials and light-curing units on diametrical tensile strength Influência do material restaurador e de aparelhos fotoativadores na resistência à tração diametral

    Directory of Open Access Journals (Sweden)

    Maria Cecília Caldas Giorgi Tolosa

    2005-06-01

    Full Text Available The aim of this study was to evaluate the diametrical tensile strength (DTS of three light-curing photo-activated composites with two different light curing units (LCU. Three types of dental restorative composites were used in this study: micro filled A110 (3M Espe; P60 (3M Espe for posterior restorations, and micro-hybrid Charisma (Heraeus-Kulzer. The two LCUs were: halogen light (HAL (Degulux, Degussa and blue light emitting diode (LED (Ultrablue, DMC. Resin composite specimens were inserted incrementally into a Teflon split mold meas-uring 3 mm in depth and 6 mm in internal diameter, and cured using either LCU (n = 10. Specimens were placed into a dark bottle containing distilled water at 37°C for 7 days. DTS tests were performed in a Universal Testing Machine (0.5 mm/min. Data were submitted to two-way ANOVA and Tukey's test. Results were (MPa: A110/HAL: 276.50 ± 62.94ª; A110/LED: 306.01 ± 65.16ª; P60/HAL: 568.29 ± 60.77b and P60/LED: 543.01 ± 83.65b; Charisma/HAL: 430.94 ± 67.28c; Charisma/LED: 435.52 ± 105.12c. Results suggested that no significant difference in DTS was obtained with LCUs for the same composite. However, resin composite restorative materials presented different DTS.O objetivo deste estudo foi avaliar a resistência à tração diametral (DTS de três compósitos fotoativados com dois aparelhos de fotoativação (LCU. Os compósitos utilizados neste estudo foram: resina de micropartículas A110 (3M Espe; P60 (3M Espe, indicada para restaurações posteriores, e micro-híbrida Charisma (Heraeus-Kulzer. As fontes de luz foram: halógena (HAL - Degulux (Degussa e luz emitida por diodos (LED - Ultrablue (DMC. As amostras foram confeccionadas através de dois incrementos inseridos em uma matriz de Teflon bipartida medindo 3 mm de profundidade e 6 mm de diâmetro interno e foram fotoativadas pelas LCUs (n = 10. As amostras foram armazenadas dentro de recipientes escuros contendo água destilada a 37°C por 7 dias. O

  10. Reineke’s stand density index: a quantitative and non-unitless measure of stand density

    Science.gov (United States)

    Curtis L. VanderSchaaf

    2013-01-01

    When used as a measure of relative density, Reineke’s stand density index (SDI) can be made unitless by relating the current SDI to a standard density but when used as a quantitative measure of stand density SDI is not unitless. Reineke’s SDI relates the current stand density to an equivalent number of trees per unit area in a stand with a quadratic mean diameter (Dq)...

  11. High Energy Density aluminum/oxygen cell

    Science.gov (United States)

    Rudd, E. J.; Gibbons, D. W.

    An alternative to a secondary battery as the power source for vehicle propulsion is a fuel cell, an example of which is the metal/air cell using metals such as aluminum, zinc, or iron. Aluminum is a particularly attractive candidate, with high energy and power densities, environmentally acceptable and having a large, established industrial base for production and distribution. An aluminum/oxygen system is currently under development for a prototype unmanned, undersea vehicle (UUV) for the US navy and recent work has focussed upon low corrosion aluminum alloys, and an electrolyte management system for processing the by-products of the energy-producing reactions. This paper summarizes the progress made in both areas. Anode materials capable of providing high utilization factors over current densities ranging from 5 to 150 mA/cm 2 have been identified, such materials being essential to realize mission life for the UUV. With respect to the electrolyte management system, a filter/precipitator unit has been successfully operated for over 250 h in a large scale, half-cell system.

  12. CsB4O6F: A Congruent-melting Deep-ultraviolet Nonlinear Optical Material with Superior Functional Units Recombination.

    Science.gov (United States)

    Wang, Xuefei; Wang, Ying; Zhang, Bingbing; Zhang, Fangfang; Yang, Zhihua; Pan, Shilie

    2017-09-12

    The discovery of new nonlinear optical (NLO) materials for coherent light generation in the deep-ultraviolet (DUV, wavelength below 200 nm) region is essential for the development of laser technologies. Herein, we report a new material CsB4O6F (CBF), which combines the superior structural genes of two famous NLO materials-β-BaB2O4 (BBO) and KBe2BO3F2 (KBBF). CBF exhibits excellent DUV optical properties including a short cutoff edge (155 nm), a large SHG response (~1.9 × KDP), and a suitable birefringence that enables frequency doubling down to 171.6 nm. Remarkably, CBF melts congruently and show an improved growth habit. In addition, our rational design strategy will contribute to the discovery of DUV NLO materials. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Density states of photonic crystal with Ⅳ-Ⅵ family of Semiconducting material%Ⅳ-Ⅵ族半导体材料构成光子晶体能态密度特性

    Institute of Scientific and Technical Information of China (English)

    王发友

    2013-01-01

    应用平面波展开法,取Ⅳ-Ⅵ族的PbS、PbSe和PbTe半导体材料构成二维三角晶格光子晶体.数值模拟其构成光子晶体能态密度特性.结果表明,随着介电常数的增大,形成的光子带隙宽度增加.结论为光子晶体器件的开发提供参考.%Two-dimensional triangle lattice photonic crystal were consist of PbS,PbSe and PbTe Ⅳ-Ⅵ family of Semiconducting material,energy state density distribute of photonic crystal were calculated by plane wave expansion method.The results show that,with the increase of dielectric constant,form the photonic band gap width increases,the normalized frequency as filling rate changes.This result provides theoretic basis theoretic basis for the photonic crystal devices.

  14. Conflict Resolution Unit.

    Science.gov (United States)

    Busselle, Tish

    This 7-day unit, intended for use with secondary students, contains a statement of rationale and objectives, lesson plans, class assignments, teacher and student bibliographies, and suggestions for instructional materials on conflict resolution between individuals, groups, and nations. Among the six objectives listed for the unit are: 1) explain…

  15. Comparison of subjective and fully automated methods for measuring mammographic density.

    Science.gov (United States)

    Moshina, Nataliia; Roman, Marta; Sebuødegård, Sofie; Waade, Gunvor G; Ursin, Giske; Hofvind, Solveig

    2017-01-01

    Background Breast radiologists of the Norwegian Breast Cancer Screening Program subjectively classified mammographic density using a three-point scale between 1996 and 2012 and changed into the fourth edition of the BI-RADS classification since 2013. In 2015, an automated volumetric breast density assessment software was installed at two screening units. Purpose To compare volumetric breast density measurements from the automated method with two subjective methods: the three-point scale and the BI-RADS density classification. Material and Methods Information on subjective and automated density assessment was obtained from screening examinations of 3635 women recalled for further assessment due to positive screening mammography between 2007 and 2015. The score of the three-point scale (I = fatty; II = medium dense; III = dense) was available for 2310 women. The BI-RADS density score was provided for 1325 women. Mean volumetric breast density was estimated for each category of the subjective classifications. The automated software assigned volumetric breast density to four categories. The agreement between BI-RADS and volumetric breast density categories was assessed using weighted kappa (kw). Results Mean volumetric breast density was 4.5%, 7.5%, and 13.4% for categories I, II, and III of the three-point scale, respectively, and 4.4%, 7.5%, 9.9%, and 13.9% for the BI-RADS density categories, respectively ( P for trend density categories was kw = 0.5 (95% CI = 0.47-0.53; P density increased with increasing density category of the subjective classifications. The agreement between BI-RADS and volumetric breast density categories was moderate.

  16. Investigation of four problems on the units of material and its properties, energy with heat and temperature in the secondary school physics textbooks

    Science.gov (United States)

    Kavcar, Nevzat; Özen, Ali Ihsan

    2017-02-01

    In the present study, three units in textbooks in accordance with the 2013 Secondary School Physics Curriculum were analyzed in defined four problems, and some recommendations were made. The study carried out in the Spring semester of education year 2015-2016, within the scope of an undergraduate course. Method of the study is the descriptive model based on qualitative research technics. The data collection instruments were textbook evaluation reports prepared by the participants and pre-service teachers, and presentations reflecting teachers' and pre-service teachers' ideas on the textbooks. A document analysis was conducted by means of these data collection tools. It has been concluded that in the related units a significant shortcoming is not found regarding being student-centered, activity and contex-based approximations. However, some shortcomings were found in activity-gain concordance with measurement and evaluation applications. On the basis of the collected data, some recommendations for improving the textbooks have been presented.

  17. Low Bone Density

    Science.gov (United States)

    ... Information › Bone Density Exam/Testing › Low Bone Density Low Bone Density Low bone density is when your ... compared to people with normal bone density. Detecting Low Bone Density A bone density test will determine ...

  18. The StreamCat Dataset: Accumulated Attributes for NHDPlusV2 Catchments (Version 2.1) for the Conterminous United States: Mine Density Active Mines and Mineral Plants in the US

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset represents the mine density within individual, local NHDPlusV2 catchments and upstream, contributing watersheds based on mine plants and operations...

  19. The StreamCat Dataset: Accumulated Attributes for NHDPlusV2 Catchments (Version 2.1) for the Conterminous United States: Mine Density Active Mines and Mineral Plants in the US

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset represents the mine density within individual, local NHDPlusV2 catchments and upstream, contributing watersheds based on mine plants and operations...

  20. The StreamCat Dataset: Accumulated Attributes for NHDPlusV2(Version 2.1) Catchments Riparian Buffer for the Conterminous United States: 2010 US Census Road Density

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset represents the road density within individual, local NHDPlusV2 catchments and upstream, contributing watersheds riparian buffers. Attributes of the...

  1. Development of the effective teaching material of the science unit "the Moon and the Sun" of the elementary school of Japan. - Method for understanding of the movement of the celestial sphere

    Science.gov (United States)

    Taketa, I.; Matsumoto, I.

    2014-12-01

    In general, elementary school teacher relatively poor at the science field about "earth and universe". There is the science unit "the Moon and the Sun" in the sixth grader in elementary school in Japan. In this study, we developed the effective teaching material that is both student is easy understanding and teacher is easy treating. The teaching material that we developed is the Movement of the Moon and the Sun using about 30-cm turntable and a USB Camera. As for the previous teaching materials, every student was checking (see) the moon and the sun spatial relationship, and the shape of the moon to each. The developed teaching material have the advantage that all student in the class can check the same phenomenon on a Video screen, by using a USB Camera. And we carried the questionnaire survey to student of attached elementary school of Shimane University. The result checked that such teaching materials were useful to a student's understanding of the movement of the celestial sphere.

  2. Effectiveness of the International Phytosanitary Standard ISPM No. 15 on reducing wood borer infestation rates in wood packaging material entering the United States

    Science.gov (United States)

    Robert A. Haack; Kerry O. Britton; Eckelhard G. Brockerhoff; Joseph F. Cavey; Lynn J. Garrett; Mark Kimberley; Frank Lowenstein; Amelia Nuding; Lars J. Olson; James Tumer; Kathryn N. Vasilaky

    2014-01-01

    Numerous bark- and wood-infesting insects have been introduced to new countries by international trade where some have caused severe environmental and economic damage. Wood packaging material (WPM), such as pallets, is one of the high risk pathways for the introduction of wood pests. International recognition of this risk resulted in adoption of International Standards...

  3. A Study of Teacher Opinions and Evaluations Concerning Selected Free Printed Materials Provided by the American Iron and Steel Institute to Individuals Throughout the United States.

    Science.gov (United States)

    DuVall, Charles R.; And Others

    The focus of this study was teacher assessment of several factors relating to selected materials provided by the American Iron and Steel Institute. The design and rationale, instrumentation, methodology, and questionnaire mailing are discussed in Chapter I. Chapter II reviews the related literature, including the historic nature of free and…

  4. The Use of Sexually Explicit Material in Clinical, Educational and Research Settings in the United Kingdom and Its Relation to the Development of Psychosexual Therapy and Sex Education

    Science.gov (United States)

    Brewster, Marnie; Wylie, Kevan R.

    2008-01-01

    The present review describes the development and use of sexually explicit material in sex education within UK psychosexual therapy clinics, medical schools and also in state-maintained secondary schools with reference to interests that have shaped the provision of sex education since the early twentieth century. A short summary of published books…

  5. Charge density waves in solids

    CERN Document Server

    Gor'kov, LP

    2012-01-01

    The latest addition to this series covers a field which is commonly referred to as charge density wave dynamics.The most thoroughly investigated materials are inorganic linear chain compounds with highly anisotropic electronic properties. The volume opens with an examination of their structural properties and the essential features which allow charge density waves to develop.The behaviour of the charge density waves, where interesting phenomena are observed, is treated both from a theoretical and an experimental standpoint. The role of impurities in statics and dynamics is considered and an

  6. Microcraters formed in glass by low density projectiles

    Science.gov (United States)

    Mandeville, J.-C.; Vedder, J. F.

    1971-01-01

    Microcraters were produced in soda-lime glass by the impact of low density projectiles of polystyrene with masses between 0.7 and 62 picograms and velocities between 2 and 14 kilometers per second. The morphology of the craters depends on the velocity and angle of incidence of the projectiles. The transitions in morphology of the craters formed by polystyrene spheres occur at higher velocities than they do for more dense projectiles. For oblique impact, the craters are elongated and shallow with the spallation threshold occuring at higher velocity. For normal incidence, the total displaced mass of the target material per unit of projectile kinetic energy increases slowly with the energy.

  7. Cooperation Between the Russia Federation and the United States to Enhance the Existing Nuclear-Material Protection, Control, and Accounting Systems at Mayak Production Association

    Energy Technology Data Exchange (ETDEWEB)

    Cahalane, P.T.; Ehinger, M.H.; James, L.T.; Jarrett, J.H.; Lundgren, R.A.; Manatt, D.R.; Niederauer, G.F.; Olivos, J.D.; Prishchepov, A.I.; Starodubtsev, G.S.; Suda, S.C.; Tittemore, G.W.; Zatorsky, Y.M.

    1999-07-19

    The Ministry of the Russian Federation for Atomic Energy (MINATOM) and the US Department of Energy (DOE) are engaged in joint, cooperative efforts to reduce the likelihood of nuclear proliferation by enhancing Material Protection, Control and Accounting (MPC&A) systems in both countries. Mayak Production Association (Mayak) is a major Russian nuclear enterprise within the nuclear complex that is operated by lylINATOM. This paper describes the nature, scope, and status of the joint, cooperative efforts to enhance existing MPC&A systems at Mayak. Current cooperative efforts are focused on enhancements to the existing MPC&A systems at two of the plants operated by Mayak that work with proliferation-sensitive nuclear materials.

  8. Determination of Physical Properties of Carbon Materials by Results of Ablative Experiments Con-ducted in the Jets of Gas Dynamic Units

    Directory of Open Access Journals (Sweden)

    V. V. Gorsky

    2015-01-01

    Full Text Available The process of hypersonic vehicles’ movement in the dense layers of the atmosphere is accompanied by the considerable combustion of heat shield, which effects on the aerodynamic, mass-inertial and centering characteristics of the product.For correct calculation of model's movement parameters it is necessary:* Using the theoretical and computation methods for determining ablative characteristics of heat-protective materials;* Taking into account all the basic physical and chemical processes, involved in their ablation, using the above mentioned methods;* Testing these techniques in the wide range of experimental data. This physic-mathematical model of carbon materials (CM aerothermochemical destruction is based on using the following:* Arrhenius equations to calculate carbon kinetic oxidation;* Langmuir-Knudsen formula to calculate the velocity of non-equilibrium carbon’s sublimation;* Carbon erosion law represented as a unique dependence of this process velocity on the gas pressure on the wall.Mathematical description of all major processes included in this formulation of the problem, contains a number of "free" parameters that can be determined only on the basis of comparison of theoretical and experimental data according to total ablation characteristics of these materials.This comparison was performed in the article applicable to the tests conditions of modern CM in the stream of electric arc plant and in combustion products of liquid-propellant rocket engines.As the result, the data of kinetic of carbon oxidation by atomic oxygen at sublimation mode of material ablation were obtained for the first time. Carbon erosion law under high pressure was established for the first time.The new approach to processing of ablation experiments is enunciated. Using this approach allows to turn this experiments for CM from comparative tests into the tests to determine ablation properties of thermal protection. Moreover, it enables us also to use the

  9. A Computer-Supported Instructional Material Design Based on 5E Learning Model: A Case of “Work, Power and Energy” Unit

    OpenAIRE

    2012-01-01

    Teaching and learning of the concept of energy and related concepts through traditional teaching methods are difficult since these concepts are abstract and their scientific meanings are different from their daily-life meanings. Moreover, another source of this difficulty is due to deficiency of appropriate teaching materials for such abstract concepts. Constructivist approach derives from students' real-world experiences and suggests the use of computer technology for solving these problems....

  10. Giant magnetostrictive materials

    Institute of Scientific and Technical Information of China (English)

    LIU JingHua; JIANG ChengBao; XU HuiBin

    2012-01-01

    Giant magnetostrictive materials are a kind of functional materials developed since 1970s,known as their large magnetostrain and high energy density.In this paper,an introduction of magnetosttiction and the history of magnetostrictive materials are described firstly.Then we review the recent developments of both rare earth and non-rare earth magnetostrictive materials.Finally,the tendency of developing new giant magnetostrictive materials is presented.

  11. Synthesis, characterization, thermal behaviour and single crystal X-ray analysis of two new insensitive high energy density materials [8-hydroxyquinolinium 5-(2,4,6-trinitrophenyl)barbiturate (I) and 8-hydroxyquinolinium 5-(5-chloro-2,4-dinitrophenyl)-1,3-dimethyl barbiturate (II)

    Science.gov (United States)

    Manickkam, V.; Devi, P. Poornima; Kalaivani, D.

    2014-12-01

    Barbiturates I and II have been synthesized as maroon red and red orange coloured solids by mixing the ethanolic solutions of 2-chloro-1,3,5-trinitrobenzene ( TNCB), pyrimidine-2,4,6(1 H,3 H,5 H)-trione [barbituric acid ( BA)] and 8-hydroxyquinoline and 1,3-dichloro-4,6-dinitrobenzene ( DCDNB), 1,3-dimethylpyrimidine-2,4,6(1 H,3 H,5 H)-trione(1,3-dimethylbarbituric acid) and 8-hydroxyquinoline respectively. The structures of these two barbiturates have been predicted from the spectral studies (UV-VIS, IR, 1H NMR, 13C NMR, mass) and elemental analysis. Qualitative tests have been carried out to infer the presence of nitrogen and nitro groups and also chlorine atom in barbiturate II. Slow evaporation of ethanol-dimethylsulphoxide/ethanol solutions of barbiturate I/barbiturate II at 293 K yielded good for X-Ray diffraction crystals. Single crystal X-ray diffraction studies of the crystals further confirm the putative structures of the barbiturates. The asymmetric unit of the barbiturate I comprises of 8-hydroxyquinolinium cation, 5-(2,4,6-trinitrophenyl) barbiturate anion and a molecule of dimethylsulphoxide (DMSO), which is used as a recrystallizing solvent. It crystallizes in the triclinic system with space group (centrosymmetric). Barbiturate II crystallizes in the orthorhombic system with space group P212121 (non-centrosymmetric). Barbiturates I and II are stable towards an impact sensitivity test, when a weight of 2 kg mass hammer is dropped from a height of 160 cm of the instrument. TGA/ DTA analyses at four different heating rates (5, 10, 20, and 40 K/min) imply that they undergo exothermic decomposition (˜85%) in three different stages between 273 and 873 K. Activation energies for these decomposition processes have been calculated by employing Kissinger and Ozawa plots. Impact sensitivity test and activation energies have revealed that the titled barbiturates are insensitive high energy density materials ( IHEDMS).

  12. 600 MW燃煤空冷机组特殊材料的焊接工艺%Special material welding process of 600 MW coal-fired air cooling unit

    Institute of Scientific and Technical Information of China (English)

    杨德云; 石南辉

    2013-01-01

    In order to of air cooling unit welding construction can have a better understanding, through their participation in the installation of the observation of shanxi mountain power plant phase ii 2×600 MW coal-fired empty cold engineering #3 unit project construction management experience was summarized, with emphasis on the special materials of the main parts of welding process (such as: SA335 - P91 joint of hot,WB36 steel welding,TP347H welding) were introduced,the hope can give similar unit installation construction and provide some reference,this project won the "2009 annual national excellent welding engineering award".%为更好地了解空冷机组焊接施工,通过对某发电厂二期2×600 MW燃煤空冷工程#3机组工程的施工管理经验进行总结,重点对特殊材料主要部件的焊接工艺(如:SA335-P91焊口的后热、WB36钢焊接、TP347H的焊接)加以介绍,希望能给类似机组的安装施工提供一些借鉴.

  13. SU-E-T-470: Importance of HU-Mass Density Calibration Technique in Proton Pencil Beam Dose Calculation

    Energy Technology Data Exchange (ETDEWEB)

    Penfold, S; Miller, A [University of Adelaide, Adelaide, SA (Australia)

    2015-06-15

    Purpose: Stoichiometric calibration of Hounsfield Units (HUs) for conversion to proton relative stopping powers (RStPs) is vital for accurate dose calculation in proton therapy. However proton dose distributions are not only dependent on RStP, but also on relative scattering power (RScP) of patient tissues. RScP is approximated from material density but a stoichiometric calibration of HU-density tables is commonly neglected. The purpose of this work was to quantify the difference in calculated dose of a commercial TPS when using HU-density tables based on tissue substitute materials and stoichiometric calibrated ICRU tissues. Methods: Two HU-density calibration tables were generated based on scans of the CIRS electron density phantom. The first table was based directly on measured HU and manufacturer quoted density of tissue substitute materials. The second was based on the same CT scan of the CIRS phantom followed by a stoichiometric calibration of ICRU44 tissue materials. The research version of Pinnacle{sup 3} proton therapy was used to compute dose in a patient CT data set utilizing both HU-density tables. Results: The two HU-density tables showed significant differences for bone tissues; the difference increasing with increasing HU. Differences in density calibration table translated to a difference in calculated RScP of −2.5% for ICRU skeletal muscle and 9.2% for ICRU femur. Dose-volume histogram analysis of a parallel opposed proton therapy prostate plan showed that the difference in calculated dose was negligible when using the two different HU-density calibration tables. Conclusion: The impact of HU-density calibration technique on proton therapy dose calculation was assessed. While differences were found in the calculated RScP of bony tissues, the difference in dose distribution for realistic treatment scenarios was found to be insignificant.

  14. Radiopacity of restorative materials using digital images.

    Science.gov (United States)

    Salzedas, Leda Maria Pescinini; Louzada, Mário Jefferson Quirino; de Oliveira Filho, Antonio Braz

    2006-04-01

    The radiopacity of esthetic restorative materials has been established as an important requirement, improving the radiographic diagnosis. The aim of this study was to evaluate the radiopacity of six restorative materials using a direct digital image system, comparing them to the dental tissues (enamel-dentin), expressed as equivalent thickness of aluminum (millimeters of aluminum). Five specimens of each material were made. Three 2-mm thick longitudinal sections were cut from an intact extracted permanent molar tooth (including enamel and dentin). An aluminum step wedge with 9 steps was used. The samples of different materials were placed on a phosphor plate together with a tooth section, aluminum step wedge and metal code letter, and were exposed using a dental x-ray unit. Five measurements of radiographic density were obtained from each image of each item assessed (restorative material, enamel, dentin, each step of the aluminum step wedge) and the mean of these values was calculated. Radiopacity values were subsequently calculated as equivalents of aluminum thickness. Analysis of variance (ANOVA) indicated significant differences in radiopacity values among the materials (Pcomposite restorations it is important that the restorative material to be used has enough radiopacity, in order to be easily distinguished from the tooth structure in the radiographic image. Knowledge on the radiopacity of different materials helps professionals to select the most suitable material, along with other properties such as biocompatibility, adhesion and esthetic.

  15. Comparison of LiV3O8 cathode materials prepared by different methods

    DEFF Research Database (Denmark)

    West, Keld; Zachau-Christiansen, Birgit; Skaarup, Steen

    1996-01-01

    (xerogels) to remove loosely bound water they show a high capacity for lithium insertion, approaching four additional lithium per formula unit, and good reversibility as electrode materials for high energy density lithium cells. How the heat-treatment temperature influences the crystal structure...

  16. Syntheses, structures and properties of two 2-D layered hybrid organic-inorganic materials based on different V4O12 building units.

    Science.gov (United States)

    Hou, Wentao; Guo, Jiuyu; Xu, Xiao; Wang, Zuoxiang; Zhang, Deng; Wan, Hongxiang; Song, You; Zhu, Dunru; Xu, Yan

    2014-01-14

    Two new layered hybrid organic-inorganic compounds [Zn(pyim)]2V4O12 () (pyim = 2-(2-pyridyl)imidazole) and [Cu(bim)2]2V4O12(H2O)·CH3CH2OH () (bim = bis(1-imidazolyl)methane) based on polyoxovanadates (POVs) and organic ligands decorated transition metal units have been synthesized by hydrothermal and solvothermal methods respectively. Single crystal XRD, fluorescence spectrum, magnetic measurement, IR spectra, powder XRD and thermogravimetric (TG) measurements were performed to analyze the structures and properties of and . The structural analysis reveals that compound features a two-dimensional {[Zn(pyim)]2V4O12}n layered structure, constructed by sine wave-like {V4O12}n(4n-) chains, Zn(2+) ions and pyim ligands. In the layered structure of , {V4O12}(4-) circles are connected by Cu(2+) ions to form {Cu(V4O12)}n(2n-) chains, which are further linked by {Cu(bim)4}(2+) subunits to generate a hybrid layer of . The magnetic susceptibility measurement indicates strong antiferromagnetic interactions between Cu(2+) ions in .

  17. EURISOL-DS multi-MW target unit: Neutronics performance and shielding assessment, dose rate and material activation calculations for the MAFF configuration

    CERN Document Server

    Romanets, Y; Kadi, Y; Luis, R; Goncalves, I F; Tecchio, L; Kharoua, C; Vaz, P; Ene, D; David, J C; Rocca, R; Negoita, F

    2010-01-01

    One of the objectives of the EURISOL (EURopean Isotope Separation On-Line Radioactive Ion Beam) Design Study consisted of providing a safe and reliable facility layout and design for the following operational parameters and characteristics: (a) a 4 MW proton beam of 1 GeV energy impinging on a mercury target (the converter); (b) high neutron fluxes (similar to 3 x 10(16) neutrons/s) generated by spallation reactions of the protons impinging in the converter and (c) fission rate on fissile U-235 targets in excess of 10(15) fissions/s. In this work, the state-of-the-art Monte Carlo codes MCNPX (Pelowitz, 2005) and FLUKA (Vlachoudis, 2009; Ferrari et al., 2008) were used to characterize the neutronics performance and to perform the shielding assessment (Herrera-Martinez and Kadi, 2006; Cornell, 2003) of the EURISOLTarget Unit and to provide estimations of dose rate and activation of different components, in view of the radiation safety assessment of the facility. Dosimetry and activation calculations were perfor...

  18. Concrete density estimation by rebound hammer method

    Science.gov (United States)

    Ismail, Mohamad Pauzi bin; Jefri, Muhamad Hafizie Bin; Abdullah, Mahadzir Bin; Masenwat, Noor Azreen bin; Sani, Suhairy bin; Mohd, Shukri; Isa, Nasharuddin bin; Mahmud, Mohamad Haniza bin

    2016-01-01

    Concrete is the most common and cheap material for radiation shielding. Compressive strength is the main parameter checked for determining concrete quality. However, for shielding purposes density is the parameter that needs to be considered. X- and -gamma radiations are effectively absorbed by a material with high atomic number and high density such as concrete. The high strength normally implies to higher density in concrete but this is not always true. This paper explains and discusses the correlation between rebound hammer testing and density for concrete containing hematite aggregates. A comparison is also made with normal concrete i.e. concrete containing crushed granite.

  19. Concrete density estimation by rebound hammer method

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, Mohamad Pauzi bin, E-mail: pauzi@nm.gov.my; Masenwat, Noor Azreen bin; Sani, Suhairy bin; Mohd, Shukri [NDT Group, Nuclear Malaysia, Bangi, Kajang, Selangor (Malaysia); Jefri, Muhamad Hafizie Bin; Abdullah, Mahadzir Bin [Material Technology Program, Faculty of Applied Sciences, UiTM, Shah Alam, Selangor (Malaysia); Isa, Nasharuddin bin; Mahmud, Mohamad Haniza bin [Pusat Penyelidikan Mineral, Jabatan Mineral dan Geosains, Ipoh, Perak (Malaysia)

    2016-01-22

    Concrete is the most common and cheap material for radiation shielding. Compressive strength is the main parameter checked for determining concrete quality. However, for shielding purposes density is the parameter that needs to be considered. X- and -gamma radiations are effectively absorbed by a material with high atomic number and high density such as concrete. The high strength normally implies to higher density in concrete but this is not always true. This paper explains and discusses the correlation between rebound hammer testing and density for concrete containing hematite aggregates. A comparison is also made with normal concrete i.e. concrete containing crushed granite.

  20. Union Density and Hospital Outcomes.

    Science.gov (United States)

    Koys, Daniel J; Martin, Wm Marty; LaVan, Helen; Katz, Marsha

    2015-01-01

    The authors address the hospital outcomes of patient satisfaction, healthcare quality, and net income per bed. They define union density as the percentage of a hospital's employees who are in unions, healthcare quality as its 30-day acute myocardial infraction (AMI; heart attack) mortality rate, and patient satisfaction as its overall Hospital Consumer Assessment of Healthcare Providers and Systems score. Using a random sample of 84 union and 84 nonunion hospitals from across the United States, multiple regression analyses show that union density is negatively related to patient satisfaction. Union density is not related to healthcare quality as measured by the AMI mortality rate or to net income per bed. This implies that unions per se are not good or bad for hospitals. The authors suggest that it is better for hospital administrators to take a Balanced Scorecard approach and be concerned about employee satisfaction, patient satisfaction, healthcare quality, and net income.

  1. Matter density versus distance for the neutrino beam from Fermilab to Lead, South Dakota, and comparison of oscillations with variable and constant density

    Science.gov (United States)

    Roe, Byron

    2017-06-01

    This paper is divided into two parts. In the first part, the material densities passed through for neutrinos going from FNAL to Sanford Laboratory are calculated using two recent density tables, Crustal [G. Laske, G. Masters, Z. Ma, and M. Pasyanos, Update on CRUST1.0—A 1-degree global model of Earth's crust, Geophys. Res. Abstracts 15, EGU2013-2658 (2013),; For the programs and tables, see the website: http://igppweb.ucsd.edu/ gabi/crust1.html.] and Shen-Ritzwoller [W. Shen and M. H. Ritzwoller, Crustal and uppermost mantle structure beneath the United States, J. Geophys. Res.: Solid Earth 121, 4306 (2016)], as well as the values from an older table PEMC [A. M. Dziewonski, A. L. Hales, and E. R. Lapwood, Parametrically simple earth models consistent with geophysical data, Phys. Earth Plan. Int. 10, 12 (1975); For further information see the website: http://ds.iris.edu/ds/products/emc-pem/.]. In the second part, neutrino oscillations at Sanford Laboratory are examined for the variable density table of Shen-Ritzwoller. These results are then compared with oscillation results using the mean density from the Shen-Ritzwoller tables and with one other fixed density. For the tests made here, the mean density results are quite similar to the results using the variable density vs distance.

  2. Moldable cork ablation material

    Science.gov (United States)

    1977-01-01

    A successful thermal ablative material was manufactured. Moldable cork sheets were tested for density, tensile strength, tensile elongation, thermal conductivity, compression set, and specific heat. A moldable cork sheet, therefore, was established as a realistic product.

  3. Quantum coherent switch utilizing commensurate nanoelectrode and charge density periodicities

    Science.gov (United States)

    Harrison, Neil; Singleton, John; Migliori, Albert

    2008-08-05

    A quantum coherent switch having a substrate formed from a density wave (DW) material capable of having a periodic electron density modulation or spin density modulation, a dielectric layer formed onto a surface of the substrate that is orthogonal to an intrinsic wave vector of the DW material; and structure for applying an external spatially periodic electrostatic potential over the dielectric layer.

  4. Research of Structure, Material Processing and Test of the United States Space Airplane%美国空天飞机计划验证飞行器结构、材料工艺及试验技术

    Institute of Scientific and Technical Information of China (English)

    卢兆勇; 郑义; 隋阳; 任湘

    2013-01-01

    Based on space airplane project of united states, X-40A, X-37A and X-37B, the paper introduces the elementary structure, material process and testing of Reusable Orbital Maneuver Vehicle(ROMV), with purpose of enabling readers to have a good understanding of manufacturing technologies of ROMV.%结合美国空天飞机计划验证飞行器X-40A、X-37A 和X-37B,介绍了可重复使用轨道机动飞行器验证试验所采用的基本结构、材料工艺和试验情况,使读者一窥可重复使用轨道机动飞行器制造技术。

  5. Density controlled carbon nanotube array electrodes

    Science.gov (United States)

    Ren, Zhifeng F [Newton, MA; Tu, Yi [Belmont, MA

    2008-12-16

    CNT materials comprising aligned carbon nanotubes (CNTs) with pre-determined site densities, catalyst substrate materials for obtaining them and methods for forming aligned CNTs with controllable densities on such catalyst substrate materials are described. The fabrication of films comprising site-density controlled vertically aligned CNT arrays of the invention with variable field emission characteristics, whereby the field emission properties of the films are controlled by independently varying the length of CNTs in the aligned array within the film or by independently varying inter-tubule spacing of the CNTs within the array (site density) are disclosed. The fabrication of microelectrode arrays (MEAs) formed utilizing the carbon nanotube material of the invention is also described.

  6. Obtaining the conversion curve of CT numbers to electron density from the effective energy of the CT using the dummy SEFM; Obtencion de la curva de conversion de numeros TC a densidad electronica a partir de la energia efectiva del TC usando el maniqui de la SEFM

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Viera Cueto, J. A.; Garcia Pareja, S.; Benitez Villegas, E. M.; Moreno Saiz, E. M.; Bodineau Gil, C.; Caudepon Moreno, F.

    2011-07-01

    The objective of this work is to obtain the conversion curve of Hounsfield units (A) versus electron densities using a mannequin with different tissue equivalent materials. This provides for the effective energy beam CT and is used to characterize the linear coefficients of absorption of different materials that comprise the dummy.

  7. Effect of comprehensive intervention for bone mineral density of patients with cerebral apoplexy in stroke unit mode%在卒中单元模式下应用综合干预对脑卒中男性患者骨密度的影响

    Institute of Scientific and Technical Information of China (English)

    刘小辉; 刘楠; 周柏玉; 王静

    2012-01-01

    Objective To discuss the application of comprehensive intervention for bone mineral density of patients with cerebral apoplexy in stroke unit mode. Methods The lumbar bone mineral density(BMD) of 400 male patients with stroke aged 40 to 75 years old was detected by using dual energy X-ray BMD apparatus and given rehabilitation exercise,nutrition,daylight balneology,therapeutic interventions,caring for protection,comprehensive health education intervention measures,again 12 months after the detection of lumbar bone mineral density(BMD). Results After the intervention,the bone density of the age bracket was improved obviously. Conclusion Comprehensive interventions can improve the bone mineral density in male patients with stroke.%目的 探讨在卒中单元模式下应用综合干预对脑卒中男性患者骨密度的影响.方法 采用双能X线BMD仪对400例年龄40~75岁脑卒中男性患者检测腰椎骨密度(BMD)并给予康复锻炼、膳食营养、日光浴疗、治疗干预、关爱防护、健康教育等综合干预措施,12个月后再次检测腰椎骨密度(BMD).结果 干预后较干预前各年龄段骨密度明显提高.结论 综合干预措施能提高脑卒中男性患者骨密度,降低骨量减少的比率.

  8. Building Blocks Incorporating Waste Materials Bound with Bitumen

    Directory of Open Access Journals (Sweden)

    Thanaya I.N.A.

    2010-01-01

    Full Text Available This paper described an investigation and evaluation which was carried out in the United Kingdom-UK, on the properties of masonry building block materials that incorporate waste materials, namely: steel slag, crushed glass, coal fly ash, rice husk ash (RHA, incinerator sewage sludge ash (ISSA, municipal solid waste incinerator bottom ash (MSWIBA or shortened as IBA, bound with bitumen or asphalt, named as Bitublock. The binder used was 50 pen bitumen. The properties of the blocks evaluated were: compressive strength, density, porosity, initial rate of suction (IRS, creep, and volume stability. It was found that the Bitublock performance can be improved by optimizing porosity and curing regime. Compaction level of 2 MPa and curing regime of 200°C for 24 hours gave satisfactory bitublock performances that at least comparable to concrete block found in the United Kingdom (UK. The Volume stability (expansion of the unit is affected by environment relative humidity.

  9. 3D simulation of the catalyst density radial distribution in a riser of the FCC unit; Simulacao 3D da distribuicao radial de densidade do catalisador num riser de uma unidade de FCC

    Energy Technology Data Exchange (ETDEWEB)

    Apolonio, Adelia M.; Santos, Valdemir A. dos; Finkler, Christine L.L. [Universidade Catolica de Pernambuco (UNICAP), Recife, PE (Brazil); Dantas, Carlos C. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear

    2008-07-01

    Local variations in the catalyst/vacuum gas oils mixing can lead to low conversions in some parts of a fluid cracking catalytic riser, while in other parts, high conversions will produce undesirable fuel gas and coke quantities. Knowledge of the apparent solid concentration in a cross-section of the riser is then essential. A computational program to generate tri dimensional graphics and level curves of the radial catalyst density in FCC risers was elaborated. The algorithm is based on determinations of the polynomial coefficients with aid of least square method and was tested with literature data, obtained by applications of nuclear technique of gamma radiation attenuation. The simulation results showed convergence with the experimental data. The precision of the mapping depends on the number of measurements and promote better conditions of diagnostic of the distribution catalyst type in the riser. (author)

  10. Density of very small meteoroids

    Science.gov (United States)

    Kikwaya Eluo, Jean-Baptiste

    2015-08-01

    chondritic-like bulk densities, suggesting either the sintering of the meteoroids through evolutionary processes, or the original radial transportation of chondritic materials up to the Kuiper Belt region.

  11. Laboratory Density Functionals

    OpenAIRE

    Giraud, B. G.

    2007-01-01

    We compare several definitions of the density of a self-bound system, such as a nucleus, in relation with its center-of-mass zero-point motion. A trivial deconvolution relates the internal density to the density defined in the laboratory frame. This result is useful for the practical definition of density functionals.

  12. Laboratory Density Functionals

    OpenAIRE

    Giraud, B G

    2007-01-01

    We compare several definitions of the density of a self-bound system, such as a nucleus, in relation with its center-of-mass zero-point motion. A trivial deconvolution relates the internal density to the density defined in the laboratory frame. This result is useful for the practical definition of density functionals.

  13. Material monitoring

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-11-01

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

  14. Absolute measurement of the effective atomic number and the electron density by using dual-energy CT images

    Science.gov (United States)

    Kim, Dae-Hong; Lee, Won-Hyung; Jeon, Sung-Soo; Kim, Hee-Joung

    2012-12-01

    Material decomposition using dual-energy and material-selective techniques was performed using computed-tomography (CT)-generated reconstructed images. Previous work using the dual-energy method focused on extracting the effective atomic number and the electron density of materials to confirm the dosimetric accuracy in radiation therapy. Dual-energy methods mostly depend on the device generating the X-rays, such as a synchrotron, and on dose verification for radiation treatment planning. Information obtained from CT imaging is important both in diagnosis and in planning radiation therapy. In a clinical setting, CT images are usually displayed as Houndsfield units (HU), which are extracted from the attenuation coefficient of a material. The attenuation coefficient is calculated using the effective atomic number and the electron density of a material; thus, information expressed in HU can be converted into the effective atomic number and the electron density by using the dual-energy equation. This study was performed using realistic Xray spectra to differentiate between the contrast media and plaque in vascular images. Our results suggest that the effective atomic number and electron density are useful in distinguishing between two adjacent materials with similar HUs.

  15. Measurement of Power Density in a Lossy Material by means of Electromagnetically induced acoustic signals for non-invasive determination of spatial thermal absorption in connection with pulsed hyperthermia

    CERN Document Server

    Caspers, Friedhelm

    1982-01-01

    For non-invasive determination of the spatial power density distribution during RF- and microwave hyperthermia it is proposed to apply the electromagnetic energy as short, high intensity pulses. This pulsed signal should have the same average power and thus give the same temperature elevation as the CW source usually applied. Due to the high peak power of the equivalent pulsed signal, with a duty cycle < 1:100, externally measurable thermoacoustic oscillations are induced in the irradiated object. They can be evaluated for the reconstruction of a spatial power density profile.

  16. Mesostructured Metal Germanium Sulfide and Selenide Materials Based on the Tetrahedral [Ge 4S 10] 4- and [Ge 4Se 10] 4- Units: Surfactant Templated Three-Dimensional Disordered Frameworks Perforated with Worm Holes

    Science.gov (United States)

    Wachhold, Michael; Kasthuri Rangan, K.; Lei, Ming; Thorpe, M. F.; Billinge, Simon J. L.; Petkov, Valeri; Heising, Joy; Kanatzidis, Mercouri G.

    2000-06-01

    The polymerization of [Ge4S10]4- and [Ge4Se10]4- unit clusters with the divalent metal ions Zn2+, Cd2+, Hg2+, Ni2+, and Co2+ in the presence of various surfactant cations leads to novel mesostructured phases. The surfactants are the quaternary ammonium salts C12H25NMe3Br, C14H29NMe3Br, C16H33NMe3Br, and C18H37NMe3Br, which play the role of templates, helping to assemble a three-dimensional mesostructured metal-germanium chalcogenide framework. These materials are stoichiometric in nature and have the formula of (R-NMe3)2[MGe4Q10] (Q=S, Se). The local atomic structure was probed by X-ray diffuse scattering and pair distribution function analysis methods and indicates that the adamantane clusters stay intact while the linking metal atoms possess a tetrahedral coordination environment. A model can be derived, from the comparison of measured and simulated X-ray powder diffraction patterns, describing the structure as an amorphous three-dimensional framework consisting of adamantane [Ge4Q10]4- units that are bridged by tetrahedral coordinated M2+ cations. The network structures used in the simulations were derived from corresponding disordered structures developed for amorphous silicon. The frameworks in (R-NMe3)2[MGe4Q10] are perforated with worm hole-like tunnels, occupied by the surfactant cations, which show no long-range order. This motif is supported by transmission electron microscopy images of these materials. The pore sizes of these channels were estimated to lie in the range of 20-30 Å, depending on the appointed surfactant cation length. The framework wall thickness of ca. 10 Å is thereby independent from the surfactant molecules used. Up to 80% of the surfactant molecules can be removed by thermal degradation under vacuum without loss of mesostructural integrity. Physical, chemical, and spectroscopic properties of these materials are discussed.

  17. High energy density aluminum battery

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Gilbert M.; Paranthaman, Mariappan Parans; Dai, Sheng; Dudney, Nancy J.; Manthiram, Arumugan; McIntyre, Timothy J.; Sun, Xiao-Guang; Liu, Hansan

    2016-10-11

    Compositions and methods of making are provided for a high energy density aluminum battery. The battery comprises an anode comprising aluminum metal. The battery further comprises a cathode comprising a material capable of intercalating aluminum or lithium ions during a discharge cycle and deintercalating the aluminum or lithium ions during a charge cycle. The battery further comprises an electrolyte capable of supporting reversible deposition and stripping of aluminum at the anode, and reversible intercalation and deintercalation of aluminum or lithium at the cathode.

  18. High energy density aluminum battery

    Science.gov (United States)

    Brown, Gilbert M.; Paranthaman, Mariappan Parans; Dai, Sheng; Dudney, Nancy J.; Manthiram, Arumugan; McIntyre, Timothy J.; Sun, Xiao-Guang; Liu, Hansan

    2016-10-11

    Compositions and methods of making are provided for a high energy density aluminum battery. The battery comprises an anode comprising aluminum metal. The battery further comprises a cathode comprising a material capable of intercalating aluminum or lithium ions during a discharge cycle and deintercalating the aluminum or lithium ions during a charge cycle. The battery further comprises an electrolyte capable of supporting reversible deposition and stripping of aluminum at the anode, and reversible intercalation and deintercalation of aluminum or lithium at the cathode.

  19. Standardizing CT lung density measure across scanner manufacturers.

    Science.gov (United States)

    Chen-Mayer, Huaiyu Heather; Fuld, Matthew K; Hoppel, Bernice; Judy, Philip F; Sieren, Jered P; Guo, Junfeng; Lynch, David A; Possolo, Antonio; Fain, Sean B

    2017-03-01

    Computed Tomography (CT) imaging of the lung, reported in Hounsfield Units (HU), can be parameterized as a quantitative image biomarker for the diagnosis and monitoring of lung density changes due to emphysema, a type of chronic obstructive pulmonary disease (COPD). CT lung density metrics are global measurements based on lung CT number histograms, and are typically a quantity specifying either the percentage of voxels with CT numbers below a threshold, or a single CT number below which a fixed relative lung volume, nth percentile, falls. To reduce variability in the density metrics specified by CT attenuation, the Quantitative Imaging Biomarkers Alliance (QIBA) Lung Density Committee has organized efforts to conduct phantom studies in a variety of scanner models to establish a baseline for assessing the variations in patient studies that can be attributed to scanner calibration and measurement uncertainty. Data were obtained from a phantom study on CT scanners from four manufacturers with several protocols at various tube potential voltage (kVp) and exposure settings. Free from biological variation, these phantom studies provide an assessment of the accuracy and precision of the density metrics across platforms solely due to machine calibration and uncertainty of the reference materials. The phantom used in this study has three foam density references in the lung density region, which, after calibration against a suite of Standard Reference Materials (SRM) foams with certified physical density, establishes a HU-electron density relationship for each machine-protocol. We devised a 5-step calibration procedure combined with a simplified physical model that enabled the standardization of the CT numbers reported across a total of 22 scanner-protocol settings to a single energy (chosen at 80 keV). A standard deviation was calculated for overall CT numbers for each density, as well as by scanner and other variables, as a measure of the variability, before and after the

  20. The use of high-density concretes in radiotherapy treatment room design.

    Science.gov (United States)

    Facure, A; Silva, A X

    2007-09-01

    With the modernization of radiotherapic centers, medical linear accelerators are largely replacing (60)Co teletherapy units. In many cases, the same vault housing the (60)Co teletherapy unit is reused for the linear accelerator and, when space is at a premium, high-density concrete (3.0-5.0 g/cm(3)) is employed to provide shielding against the primary, scatter and leakage radiation. This work presents a study based on Monte Carlo simulations of transmission of some clinical photon spectra (of 4-10 MV accelerators) through some types of high-density concretes, normally used in the construction of radiotherapy bunkers. From the simulations, the initial and subsequent tenth-value layers (TVL) for these materials, taking into account realistic clinical photon spectra, are presented, for primary radiation.