WorldWideScience

Sample records for semi conducting properties

  1. Dielectric properties and conductivity of carbon nanofiber/semi-crystalline polymer composites

    International Nuclear Information System (INIS)

    Sui, G.; Jana, S.; Zhong, W.H.; Fuqua, M.A.; Ulven, C.A.

    2008-01-01

    The properties of semi-crystalline polymer nanocomposites are affected by the nanofillers directly and indirectly, as two phases, i.e., crystalline and amorphous, exist in the polymer. The effects of nanofillers on the two phases could be competitive. The dielectric properties and conductivity of carbon nanofibers (CNF)/semi-crystalline polymer nanocomposites are studied in this paper. CNF/polypropylene (PP) nanocomposites are prepared in experiment by melt blending. The resulting morphology and crystalline structure are characterized by means of differential scanning calorimetry, wide angle X-ray diffraction and scanning electron microscopy. The PP nanocomposite containing 5 wt.% CNF exhibits a surprisingly high dielectric constant under wide sweep frequencies attended by low dielectric loss. Its dielectric constant is >600 under lower frequency, and remains >200 at a frequency of 4000 Hz. The electrical and thermal conductivities of the nanocomposites are studied, and enhancements are seen with increased CNF content. Theoretical analyses on the physical properties are carried out by applying the existing models. Research results indicate that a common commercial plastic with good comprehensive performance, which exhibited the potential for applications in advanced electronics, was obtained by a simple industry benign technique

  2. Thermal Conductance and High-Frequency Properties of Cryogenic Normal or Superconducting Semi-rigid Coaxial Cables in the Temperature Range of 1-8 K

    Science.gov (United States)

    Kushino, A.; Kasai, S.; Ukibe, M.; Ohkubo, M.

    2018-04-01

    In this study, the characteristics of thin semi-rigid cables composed of different conductors and with outer diameters ranging from 0.86 to 1.19 mm were investigated at low temperatures. The thermal conductance was measured between approximately 1 and 8 K, and the frequency dependence of the attenuation in the cables was obtained at 3 K. The electrical conductors used in the cables were alloys: beryllium copper, brass, stainless steel (SUS304), phosphor bronze, cupronickel (CuNi), and niobium-titanium (NbTi). The thermal conductance of a commercial miniature coaxial cable with braided wires forming the outer electrical conductor was also examined for reference. The measured thermal conductance was compared to published data and that generated from material libraries and databases. Among the measured cables using normal metals, the semi-rigid cable composed of SUS304 conductors and a polytetrafluoroethylene insulator showed the lowest thermal conductance. The transmission performance of the semi-rigid cables using SUS304 or CuNi was improved by plating the central conductors with a silver coating of approximately 3 μm thickness, and their thermal conductance with the plating increased by approximately one order of magnitude. The superconducting NbTi semi-rigid cable exhibited the lowest thermal conductance of all the cables considered in the present study along with very small attenuation up to above 5 GHz.

  3. Paramagnetic resonance and electronic conduction in organic semiconductors; Resonance paramagnetique et conduction electroniques dans les semi-conducteurs organiques

    Energy Technology Data Exchange (ETDEWEB)

    Nechtschein, M. [Commissariat a l' energie atomique et aux energies alternatives - CEA, Laboratoire de Resonance Magnetique (France)

    1963-07-01

    As some organic bodies simultaneously display semi-conducting properties and a paramagnetism, this report addresses the study of conduction in organic bodies. The author first briefly recalls how relationships between conductibility and Electron Paramagnetic Resonance (EPR) can be noticed in a specific case (mineral and metallic semiconductors). He discusses published results related to paramagnetism and conductibility in organic bodies. He reviews various categories of organic bodies in which both properties are simultaneously present. He notably addresses radical molecular crystals, non-radical molecular crystals, charge transfer complexes, pyrolyzed coals, and pseudo-ferromagnetic organic structures. He discusses the issue of relationships between conduction (charge transfer by electrons) and ERP (which reveals the existence of non-paired electrons which provide free spins)

  4. Heat Conduction Analysis Using Semi Analytical Finite Element Method

    International Nuclear Information System (INIS)

    Wargadipura, A. H. S.

    1997-01-01

    Heat conduction problems are very often found in science and engineering fields. It is of accrual importance to determine quantitative descriptions of this important physical phenomena. This paper discusses the development and application of a numerical formulation and computation that can be used to analyze heat conduction problems. The mathematical equation which governs the physical behaviour of heat conduction is in the form of second order partial differential equations. The numerical resolution used in this paper is performed using the finite element method and Fourier series, which is known as semi-analytical finite element methods. The numerical solution results in simultaneous algebraic equations which is solved using the Gauss elimination methodology. The computer implementation is carried out using FORTRAN language. In the final part of the paper, a heat conduction problem in a rectangular plate domain with isothermal boundary conditions in its edge is solved to show the application of the computer program developed and also a comparison with analytical solution is discussed to assess the accuracy of the numerical solution obtained

  5. Properties of semi-infinite nuclei

    International Nuclear Information System (INIS)

    El-Jaick, L.J.; Kodama, T.

    1976-04-01

    Several relations among density distributions and energies of semi-infinite and infinite nuclei are iventigated in the framework of Wilets's statistical model. The model is shown to be consistent with the theorem of surface tension given by Myers and Swiatecki. Some numerical results are shown by using an appropriate nuclear matter equation of state

  6. Organic semi-conducting architectures for supramolecular electronics

    NARCIS (Netherlands)

    Leclère, P.E.L.G.; Surin, M.; Jonkheijm, P.; Henze, O.; Schenning, A.P.H.J.; Biscarini, F.; Grimsdale, A.C.; Feast, W.J.; Meijer, E.W.; Müllen, K.; Brédas, J.L.; Lazzaroni, R.

    2004-01-01

    The properties of organic electronic materials in the solid-state are determined not only by those of individual molecules but also by those of ensembles of molecules. The ability to control the architectures of these ensembles is thus essential for optimizing the properties of conjugated materials

  7. Semi-conducting plastics for disposable electronic devices - What are the organic semi-conductors arriving on the market?; Des plastiques semi-conducteurs pour l'electronique jetable. Qui sont les semi-conducteurs organiques qui arrivent sur le marche?

    Energy Technology Data Exchange (ETDEWEB)

    Nueesch, F. A. [EMPA, Duebendorf (Switzerland)

    2010-07-01

    This is a popularization article that describes basic properties of semi-conductors and reports on the status of research and development of organic semi-conductors. In a first part, fundamentals of semi-conductors are recalled. Comparisons are made between inorganic and organic (i.e. based on carbon polymers) compounds. Indications are given on how semi-conducting polymers are obtained. Potential applications are listed: flexible organic solar cells, light emitting diodes, flexible organic displays, intelligent cards for ticketing, etc. Research on organic semi-conductors is of great interest for industry, worldwide, and several companies are widely investing in this area.

  8. Conductive properties of methanogenic biofilms.

    Science.gov (United States)

    Li, Cheng; Lesnik, Keaton Larson; Liu, Hong

    2018-02-01

    Extracellular electron transfer between syntrophic partners needs to be efficiently maintained in methanogenic environments. Direct extracellular electron transfer via electrical current is an alternative to indirect hydrogen transfer but requires construction of conductive extracellular structures. Conductive mechanisms and relationship between conductivity and the community composition in mixed-species methanogenic biofilms are not well understood. The present study investigated conductive behaviors of methanogenic biofilms and examined the correlation between biofilm conductivity and community composition between different anaerobic biofilms enriched from the same inoculum. Highest conductivity observed in methanogenic biofilms was 71.8±4.0μS/cm. Peak-manner response of conductivity upon changes over a range of electrochemical potentials suggests that electron transfer in methanogenic biofilms occurs through redox driven super-exchange. The strong correlation observed between biofilm conductivity and Geobacter spp. in the metabolically diverse anaerobic communities suggests that the efficiency of DEET may provide pressure for microbial communities to select for species that can produce electrical conduits. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Semi-metallic, strong conductive polymer microfiber, method and fast response rate actuators and heating textiles

    KAUST Repository

    Zhou, Jian; Li, Er Qiang; Lubineau, Gilles; Thoroddsen, Sigurdur T; Mulle, Matthieu

    2016-01-01

    A method comprising: providing at least one first composition comprising at least one conjugated polymer and at least one solvent, wet spinning the at least one first composition to form at least one first fiber material, hot-drawing the at least one fiber to form at least one second fiber material. In lead embodiments, high-performance poly(3,4-ethylenedioxy- thiophene)/poly(styrenesulfonate) (PEDOT/PSS) conjugated polymer microfibers were fabricated via wet- spinning followed by hot-drawing. In these lead embodiments, due to the combined effects of the vertical hot-drawing process and doping/de-doping the microfibers with ethylene glycol (EG), a record electrical conductivity of 2804 S · cm-1 was achieved. This is believed to be a six-fold improvement over the best previously reported value for PEDOT/PSS fibers (467 S · cm-1) and a twofold improvement over the best values for conductive polymer films treated by EG de-doping (1418 S · cm-1). Moreover, these lead, highly conductive fibers experience a semiconductor-metal transition at 313 K. They also have superior mechanical properties with a Young's modulus up to 8.3 GPa, a tensile strength reaching 409.8 MPa and a large elongation before failure (21%). The most conductive fiber also demonstrates an extraordinary electrical performance during stretching/unstretching: the conductivity increased by 25% before the fiber rupture point with a maximum strain up to 21%. Simple fabrication of the semi-metallic, strong and stretchable wet-spun PEDOT/PSS microfibers can make them available for conductive smart electronics. A dramatic improvement in electrical conductivity is needed to make conductive polymer fibers viable candidates in applications such as flexible electrodes, conductive textiles, and fast-response sensors and actuators.

  10. Semi-metallic, strong conductive polymer microfiber, method and fast response rate actuators and heating textiles

    KAUST Repository

    Zhou, Jian

    2016-06-09

    A method comprising: providing at least one first composition comprising at least one conjugated polymer and at least one solvent, wet spinning the at least one first composition to form at least one first fiber material, hot-drawing the at least one fiber to form at least one second fiber material. In lead embodiments, high-performance poly(3,4-ethylenedioxy- thiophene)/poly(styrenesulfonate) (PEDOT/PSS) conjugated polymer microfibers were fabricated via wet- spinning followed by hot-drawing. In these lead embodiments, due to the combined effects of the vertical hot-drawing process and doping/de-doping the microfibers with ethylene glycol (EG), a record electrical conductivity of 2804 S · cm-1 was achieved. This is believed to be a six-fold improvement over the best previously reported value for PEDOT/PSS fibers (467 S · cm-1) and a twofold improvement over the best values for conductive polymer films treated by EG de-doping (1418 S · cm-1). Moreover, these lead, highly conductive fibers experience a semiconductor-metal transition at 313 K. They also have superior mechanical properties with a Young\\'s modulus up to 8.3 GPa, a tensile strength reaching 409.8 MPa and a large elongation before failure (21%). The most conductive fiber also demonstrates an extraordinary electrical performance during stretching/unstretching: the conductivity increased by 25% before the fiber rupture point with a maximum strain up to 21%. Simple fabrication of the semi-metallic, strong and stretchable wet-spun PEDOT/PSS microfibers can make them available for conductive smart electronics. A dramatic improvement in electrical conductivity is needed to make conductive polymer fibers viable candidates in applications such as flexible electrodes, conductive textiles, and fast-response sensors and actuators.

  11. Proton conductive membranes based on poly (styrene-co-allyl alcohol semi-IPN

    Directory of Open Access Journals (Sweden)

    Felipe Augusto Moro Loureiro

    2014-01-01

    Full Text Available The optimization of fuel cell materials, particularly polymer membranes, for PEMFC has driven the development of methods and alternatives to achieve systems with more adequate properties to this application. The sulfonation of poly (styrene-co-allyl alcohol (PSAA, using sulfonating agent:styrene ratios of 2:1, 1:1, 1:2, 1:4, 1:6, 1:8 and 1:10, was previously performed to obtain proton conductive polymer membranes. Most of those membranes exhibited solubility in water with increasing temperature and showed conductivity of approximately 10-5 S cm-1. In order to optimize the PSAA properties, especially decreasing its solubility, semi-IPN (SIPN membranes are proposed in the present study. These membranes were obtained from the diglycidyl ether of bisphenol A (DGEBA, curing reactions in presence of DDS (4,4-diaminodiphenyl sulfone and PSAA. Different DGEBA/PSAA weight ratios were employed, varying the PSAA concentration between 9 and 50% and keeping the mass ratio of DGEBA:DDS as 1:1. The samples were characterized by FTIR and by electrochemical impedance spectroscopy. Unperturbed bands of PSAA were observed in the FTIR spectra of membranes, suggesting that chemical integrity of the polymer is maintained during the synthesis. In particular, bands involving C-C stretching (1450 cm-1, C=C (aromatic, ~ 3030 cm-1 and C-H (2818 and 2928 cm-1 were observed, unchanged after the synthesis. The disappearance or reduction of the intensity of the band at 916 cm-1, attributed to the DGEBA epoxy ring, is evidenced for all samples, indicating the epoxy ring opening and the DGEBA crosslinking. Conductivity of H3PO4 doped membranes increases with temperature, reaching 10-4 S cm-1.

  12. Semi-convergence properties of Kaczmarz’s method

    International Nuclear Information System (INIS)

    Elfving, Tommy; Hansen, Per Christian; Nikazad, Touraj

    2014-01-01

    Kaczmarz’s method—sometimes referred to as the algebraic reconstruction technique—is an iterative method that is widely used in tomographic imaging due to its favorable semi-convergence properties. Specifically, when applied to a problem with noisy data, during the early iterations it converges very quickly toward a good approximation of the exact solution, and thus produces a regularized solution. While this property is generally accepted and utilized, there is surprisingly little theoretical justification for it. The purpose of this paper is to present insight into the semi-convergence of Kaczmarz’s method as well as its projected counterpart (and their block versions). To do this we study how the data errors propagate into the iteration vectors and we derive upper bounds for this noise propagation. Our bounds are compared with numerical results obtained from tomographic imaging. (paper)

  13. Surface properties of semi-infinite Fermi systems

    International Nuclear Information System (INIS)

    Campi, X.; Stringari, S.

    1979-10-01

    A functional relation between the kinetic energy density and the total density is used to analyse the surface properties of semi-infinite Fermi systems. One find an explicit expression for the surface thickness in which the role of the infinite matter compressibility, binding energy and non-locality effects is clearly shown. The method, which holds both for nuclear and electronic systems (liquid metals), yields a very simple relation between the surface thickness and the surface energy

  14. Electrical and Electrochemical Properties of Conducting Polymers

    Directory of Open Access Journals (Sweden)

    Thanh-Hai Le

    2017-04-01

    Full Text Available Conducting polymers (CPs have received much attention in both fundamental and practical studies because they have electrical and electrochemical properties similar to those of both traditional semiconductors and metals. CPs possess excellent characteristics such as mild synthesis and processing conditions, chemical and structural diversity, tunable conductivity, and structural flexibility. Advances in nanotechnology have allowed the fabrication of versatile CP nanomaterials with improved performance for various applications including electronics, optoelectronics, sensors, and energy devices. The aim of this review is to explore the conductivity mechanisms and electrical and electrochemical properties of CPs and to discuss the factors that significantly affect these properties. The size and morphology of the materials are also discussed as key parameters that affect their major properties. Finally, the latest trends in research on electrochemical capacitors and sensors are introduced through an in-depth discussion of the most remarkable studies reported since 2003.

  15. Thermostatic properties of semi-infinite polarized nuclear matter

    International Nuclear Information System (INIS)

    Abd-Alla, M.; Hassan, M.Y.M.; Ramadan, S.

    1988-03-01

    The surface and curvature properties of semi-infinite polarized nuclear matter (SPNM) are calculated using an expansion for the Fermi integrals up to T 2 . A density matrix expansion is obtained for a modified form of Seyler-Blanchard interaction. New parameters that characterize the surface and curvature properties of SPNM are introduced. The level density parameter is extracted from the low temperature expansion of the free energy and compared with previous calculations. A reasonable agreement is obtained for the parameters calculated before. (author). 78 refs, 1 fig., 5 tabs

  16. Thermal conductivity of organic semi-conducting materials using 3omega and photothermal radiometry techniques

    Directory of Open Access Journals (Sweden)

    Reisdorffer Frederic

    2014-01-01

    Full Text Available Organic semiconductors for opto-electronic devices show several defects which can be enhanced while increasing the operating temperature. Their thermal management and especially the reduction of their temperature are of great interest. For the heat transfer study, one has to measure the thermal conductivity of thin film organic materials. However the major difficulty for this measurement is the very low thickness of the films which needs the use of very specific techniques. In our work, the 3-omega and photothermal radiometric methods were used to measure the thermal conductivity of thin film organic semiconducting material (Alq3. The measurements were performed as function of the thin film thickness from 45 to 785 nm and also of its temperature from 80 to 350 K. With the 3 omega method, a thermal conductivity value of 0.066 W.m−1K−1 was obtained for Alq3 thin film of 200 nm at room temperature, in close agreement with the photothermal value. Both techniques appear to be complementary: the 3 omega method is easier to implement for large temperature range and small thicknesses down to a few tens of nanometers whereas the photothermal method is more suitable for thicknesses over 200nm since it provides additional information such as the thin film volumetric heat capacity.

  17. Thin sensing layer based on semi-conducting β-cyclodextrin rotaxane for toxic metals detection

    Energy Technology Data Exchange (ETDEWEB)

    Teka, S.; Gaied, A.; Jaballah, N. [Laboratoire des Interfaces et Matériaux Avancés (LIMA), Université de Monastir, Faculté des Sciences de Monastir, Bd. de l' Environnement, 5019 Monastir (Tunisia); Xiaonan, S. [Université Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baı̈ f, 75205 Paris Cedex 13 (France); Majdoub, M., E-mail: mustapha.majdoub@fsm.rnu.tn [Laboratoire des Interfaces et Matériaux Avancés (LIMA), Université de Monastir, Faculté des Sciences de Monastir, Bd. de l' Environnement, 5019 Monastir (Tunisia)

    2016-02-15

    Highlights: • Microwave-assisted synthesis of rotaxane based on anthracene and β-cyclodextrin. • Morphological and optical characterization of thin solid film. • Elaboration of impedimetric gold/rotaxane sensor. • Investigation of the membrane sensitivity towards Hg{sup 2+}, Cu{sup 2+} and Pb{sup 2+} cations. - Abstract: An impedimetric sensor based on a new semi-conducting rotaxane has been described for detection of toxic cations. The rotaxane, consists on a π-conjugated material encapsulated into β-cyclodextrin (β-CD); it has been synthesized via the Williamson reaction under microwaves irradiation. The supramolecular structure of the compound was confirmed by NMR and FT-IR spectroscopies. A thin solid film of the rotaxane was deposited by spin-coating to develop a new electrochemical sensor. The morphological properties of the organic membrane were evaluated using contact angle measurements and atomic force microscopy. The gold/rotaxane/solution interfaces were investigated by electrochemical impedance spectroscopy and the obtained data were fitted using an equivalent electrical circuit. The response of the gold/rotaxane membrane towards Hg{sup 2+}, Cu{sup 2+} and Pb{sup 2+} cations was studied and the results showed a good sensitivity to the mercury cations.

  18. Growth and Functionality of Cells Cultured on Conducting and Semi-Conducting Surfaces Modified with Self-Assembled Monolayers (SAMs

    Directory of Open Access Journals (Sweden)

    Rajendra K. Aithal

    2016-02-01

    Full Text Available Bioengineering of dermal and epidermal cells on surface modified substrates is an active area of research. The cytotoxicity, maintenance of cell phenotype and long-term functionality of human dermal fibroblast (HDF cells on conducting indium tin oxide (ITO and semi-conducting, silicon (Si and gallium arsenide (GaAs, surfaces modified with self-assembled monolayers (SAMs containing amino (–NH2 and methyl (–CH3 end groups have been investigated. Contact angle measurements and infrared spectroscopic studies show that the monolayers are conformal and preserve their functional end groups. Morphological analyses indicate that HDFs grow well on all substrates except GaAs, exhibiting their normal spindle-shaped morphology and exhibit no visible signs of stress or cytoplasmic vacuolation. Cell viability analyses indicate little cell death after one week in culture on all substrates except GaAs, where cells died within 6 h. Cells on all surfaces proliferate except on GaAs and GaAs-ODT. Cell growth is observed to be greater on SAM modified ITO and Si-substrates. Preservation of cellular phenotype assessed through type I collagen immunostaining and positive staining of HDF cells were observed on all modified surfaces except that on GaAs. These results suggest that conducting and semi-conducting SAM-modified surfaces support HDF growth and functionality and represent a promising area of bioengineering research.

  19. Semi-convergence properties of Kaczmarz’s method

    DEFF Research Database (Denmark)

    Elfving, Tommy; Hansen, Per Christian; Nikazad, Touraj

    2014-01-01

    Kaczmarz’s method—sometimes referred to as the algebraic reconstruction technique—is an iterative method that is widely used in tomographic imaging due to its favorable semi-convergence properties. Specifically, when applied to a problem with noisy data, during the early iterations it converges......-convergence of Kaczmarz’s method as well as its projected counterpart (and their block versions). To do this we study how the data errors propagate into the iteration vectors and we derive upper bounds for this noise propagation. Our bounds are compared with numerical results obtained from tomographic imaging....

  20. Properties of conductive thick-film inks

    Science.gov (United States)

    Holtze, R. F.

    1972-01-01

    Ten different conductive inks used in the fabrication of thick-film circuits were evaluated for their physical and handling properties. Viscosity, solid contents, and spectrographic analysis of the unfired inks were determined. Inks were screened on ceramic substrates and fired for varying times at specified temperatures. Selected substrates were given additional firings to simulate the heat exposure received if thick-film resistors were to be added to the same substrate. Data are presented covering the (1) printing characteristics, (2) solderability using Sn-63 and also a 4 percent silver solder, (3) leach resistance, (4) solder adhesion, and (5) wire bonding properties. Results obtained using different firing schedules were compared. A comparison was made between the various inks showing general results obtained for each ink. The changes in firing time or the application of a simulated resistor firing had little effect on the properties of most inks.

  1. Preoperative headband assessment for semi-implantable bone conduction hearing devices in conductive hearing loss: is it useful or misleading?

    Science.gov (United States)

    Rainsbury, James W; Williams, Blair A; Gulliver, Mark; Morris, David P

    2015-02-01

    To establish whether preoperative assessment using a conventional, percutaneous bone conducting implant (pBCI) processor on a headband accurately represents postoperative performance of a semi-implantable BCI (siBCI). Retrospective case series. Tertiary otology unit. Five patients with chronic otitis media (implanted unilaterally) and one with bilateral congenital ossicular fixation (implanted bilaterally). Semi-implantable bone conduction hearing implant. Functional hearing gain; preoperative (headband) versus postoperative (aided) speech discrimination; unaided bone conduction (BC) versus postoperative (aided) soundfield threshold. Significant functional gain was seen at all frequencies (one-tailed t test p G 0.01; n = 7). There was a 50 dB improvement in median speech reception threshold (SRT) from 70 dB unaided to 20 dB aided. Compared to the preoperative BC, aided siBCI thresholds were worse at 0.5 kHz, but at frequencies from 1 to 6 kHz, the siBCI closely matched the bone curve ( p G 0.01). The siBCI performed better than both pBCI processors on a headband at 3 to 4 kHz, except 1 kHz ( p G 0.01). BC thresholds may be a better indicator of implant performance than headband assessment. Candidacy assessment for siBCI implantation that relies on headband testing with pBCI processors should be interpreted with caution because the headband may under-represent the implanted device. This seems to be especially true at 3 kHz and above and may make it difficult for surgeons to conduct accurate informed consent discussions with patients about the realistic anticipated outcomes and benefits of the procedure.

  2. Bias-dependent amino-acid-induced conductance changes in short semi-metallic carbon nanotubes

    International Nuclear Information System (INIS)

    Abadir, G B; Walus, K; Pulfrey, D L

    2010-01-01

    We study the interaction between short semi-metallic carbon nanotubes and different amino acids using molecular dynamics and ab initio (density functional theory/non-equilibrium Green's function) simulations. We identify two different mechanisms of nanotube conductance change upon adsorption of amino acids: one due to the change of the coordinates of the nanotube arising from van der Waals forces of interaction with the adsorbed amino acid; and one due to electrostatic interactions, which appear only in the case of charged amino acids. We also find that the transport mechanism and the changes in the conductance of the tube upon amino acid adsorption are bias dependent.

  3. Relaxation Mechanisms, Structure and Properties of Semi-Coherent Interfaces

    Directory of Open Access Journals (Sweden)

    Shuai Shao

    2015-10-01

    Full Text Available In this work, using the Cu–Ni (111 semi-coherent interface as a model system, we combine atomistic simulations and defect theory to reveal the relaxation mechanisms, structure, and properties of semi-coherent interfaces. By calculating the generalized stacking fault energy (GSFE profile of the interface, two stable structures and a high-energy structure are located. During the relaxation, the regions that possess the stable structures expand and develop into coherent regions; the regions with high-energy structure shrink into the intersection of misfit dislocations (nodes. This process reduces the interface excess potential energy but increases the core energy of the misfit dislocations and nodes. The core width is dependent on the GSFE of the interface. The high-energy structure relaxes by relative rotation and dilatation between the crystals. The relative rotation is responsible for the spiral pattern at nodes. The relative dilatation is responsible for the creation of free volume at nodes, which facilitates the nodes’ structural transformation. Several node structures have been observed and analyzed. The various structures have significant impact on the plastic deformation in terms of lattice dislocation nucleation, as well as the point defect formation energies.

  4. Influence of Conductive and Semi-Conductive Nanoparticles on the Dielectric Response of Natural Ester-Based Nanofluid Insulation

    Directory of Open Access Journals (Sweden)

    M. Z. H. Makmud

    2018-02-01

    Full Text Available Nowadays, studies of alternative liquid insulation in high voltage apparatus have become increasingly important due to higher concerns regarding safety, sustainable resources and environmentally friendly issues. To fulfil this demand, natural ester has been extensively studied and it can become a potential product to replace mineral oil in power transformers. In addition, the incorporation of nanoparticles has been remarkable in producing improved characteristics of insulating oil. Although much extensive research has been carried out, there is no general agreement on the influence on the dielectric response of base oil due to the addition of different amounts and conductivity types of nanoparticle concentrations. Therefore, in this work, a natural ester-based nanofluid was prepared by a two-step method using iron oxide (Fe2O3 and titanium dioxide (TiO2 as the conductive and semi-conductive nanoparticles, respectively. The concentration amount of each nanoparticle types was varied at 0.01, 0.1 and 1.0 g/L. The nanofluid samples were characterised by visual inspection, morphology and the dynamic light scattering (DLS method before the dielectric response measurement was carried out for frequency-dependent spectroscopy (FDS, current-voltage (I-V, and dielectric breakdown (BD strength. The results show that the dielectric spectra and I-V curves of nanofluid-based iron oxide increases with the increase of iron oxide nanoparticle loading, while for titanium dioxide, it exhibits a decreasing response. The dielectric BD strength is enhanced for both types of nanoparticles at 0.01 g/L concentration. However, the increasing amount of nanoparticles at 0.1 and 1.0 g/L led to a contrary dielectric BD response. Thus, the results indicate that the augmentation of conductive nanoparticles in the suspension can lead to overlapping mechanisms. Consequently, this reduces the BD strength compared to pristine materials during electron injection in high electric

  5. Stomatal conductance of semi-natural Mediterranean grasslands: Implications for the development of ozone critical levels

    International Nuclear Information System (INIS)

    Alonso, R.; Bermejo, V.; Sanz, J.; Valls, B.; Elvira, S.; Gimeno, B.S.

    2007-01-01

    Intra-genus and intra-specific variation and the influence of nitrogen enrichment on net assimilation and stomatal conductance of some annual Trifolium species of Mediterranean dehesa grasslands were assessed under experimental conditions. Also gas exchange rates were compared between some Leguminosae and Poaceae species growing in the field in a dehesa ecosystem in central Spain. The results showed that the previously reported different O 3 sensitivity of some Trifolium species growing in pots does not seem to be related to different maximum g s values. In addition, no clear differences on gas exchange rates could be attributed to Leguminosae and Poaceae families growing in the field, with intra-genus variation being more important than differences found between families. Further studies are needed to increase the database for developing a flux-based approach for setting O 3 critical levels for semi-natural Mediterranean species. - The stomatal conductance model incorporated within the EMEP DO 3 SE deposition module needs to be re-parameterised for Mediterranean semi-natural vegetation

  6. Surface and conductivity properties of imidazoles solutions

    International Nuclear Information System (INIS)

    Rogalski, Marek; Domanska, Urszula; Czyrny, Dagmara; Dyczko, Dagmara

    2002-01-01

    The surface tension, σ, of the solutions of benzimidazole, 2-phenylimidazole and 2,4,5-triphenylimidazole in water, or water + 10 mol% of acetonitrile, or in other solvents as well as the solubilities and conductivity of benzimidazole and 2-phenylimidazole in water in function of concentration at 298.15 K were measured. The enthalpy of fusion, or solid-solid phase transition and the melting temperatures were determined for the substances under study by the scanning calorimetry (DSC). These solutions exhibit, in a wide range of concentrations, the normal linear, or parabolic decreasing dependencies and the maximum of surface tension at very low concentrations and show the S-shaped dependencies, being in function of the initial sample, never reported before. The results were confirmed by the conductivity measurements. The results were interpreted in terms of the changing structure of the interface. It was concluded that the observed phenomena were caused by an induced nucleation of benzimidazole, 2-phenylimidazole and especially by 2,4,5-triphenylimidazole by columnar discotic structures due to the initial concentration. The surface properties of these solutions reflect the interactions of hydrophobic parts of the guest molecules adsorbed at the interface, as a result of the hydrogen bonded structure of the solution

  7. Evaluating soil moisture and hydraulic conductivity in semi-arid rangeland soils

    International Nuclear Information System (INIS)

    Whitaker, M.P.L.

    1993-01-01

    The US DOE's Office of Civilian Radioactive Waste Management (DOE-OCRWM) Fellowship Program supports various disciplines of academic research related to the isolation of radionuclides from the biosphere. The purpose of this paper is to provide an example of a university research application in the specific discipline of hydrology and water resources (a multi-disciplinary field encompassing engineering and the earth sciences), and to discuss how this research pertains to the objectives of the DOE-OCRWM Fellowship Program. The university research application is twofold: One portion focuses on the spatial variability of soil moisture (θ) and the other section compares point measurements with small watershed estimates of hydraulic conductivity (K) in a semi-arid rangeland soil in Arizona. For soil moisture measurements collected over a range of horizontal sampling intervals, no spatial correlation was evident. This outcome is reassuring to computer modelers who have assumed no spatial correlation for soil moisture over smaller scales. In regard to hydraulic conductivity, point measurements differed significantly from small watershed estimates of hydraulic conductivity which were derived from a calibrated and verified rainfall-runoff computer model. The estimates of saturated hydraulic conductivity (Ks) were obtained from previous computer simulations in which measured data was collected in the same research location as the present study

  8. Conduction properties of strongly interacting Fermions

    Science.gov (United States)

    Brantut, Jean-Philippe; Stadler, David; Krinner, Sebastian; Meineke, Jakob; Esslinger, Tilman

    2013-05-01

    We experimentally study the transport process of ultracold fermionic atoms through a mesoscopic, quasi two-dimensional channel connecting macroscopic reservoirs. By observing the current response to a bias applied between the reservoirs, we directly access the resistance of the channel in a manner analogous to a solid state conduction measurement. The resistance is further controlled by a gate potential reducing the atomic density in the channel, like in a field effect transistor. In this setup, we study the flow of a strongly interacting Fermi gas, and observe a striking drop of resistance with increasing density in the channel, as expected at the onset of superfluidity. We relate the transport properties to the in-situ evolution of the thermodynamic potential, providing a model independant thermodynamic scale. The resistance is compared to that of an ideal Fermi gas in the same geometry, which shows an order of magnitude larger resistance, originating from the contact resistance between the channel and the reservoirs. The extension of this study to a channel containing a tunable disorder is briefly outlined.

  9. Synthesis of conductive semi-transparent silver films deposited by a Pneumatically-Assisted Ultrasonic Spray Pyrolysis Technique

    Energy Technology Data Exchange (ETDEWEB)

    Zaleta-Alejandre, E.; Balderas-Xicoténcatl, R. [Centro de Investigación y de Estudios Avanzados-IPN, Departamento de Física, , Apdo. Postal 14-470, Del, Gustavo A. Madero, C.P. 07000, México, D.F. (Mexico); Arrieta, M.L. Pérez [Universidad Autónoma de Zacatecas, Unidad Académica de Física, Calzada Solidaridad esq. Paseo, La Bufa s/n, C.P. 98060, Zacatecas, México (Mexico); Meza-Rocha, A.N.; Rivera-Álvarez, Z. [Centro de Investigación y de Estudios Avanzados-IPN, Departamento de Física, , Apdo. Postal 14-470, Del, Gustavo A. Madero, C.P. 07000, México, D.F. (Mexico); Falcony, C., E-mail: cfalcony@fis.cinvestav.mx [Centro de Investigación y de Estudios Avanzados-IPN, Departamento de Física, , Apdo. Postal 14-470, Del, Gustavo A. Madero, C.P. 07000, México, D.F. (Mexico)

    2013-10-01

    Highlights: • We deposited metallic silver films without post-deposition annealing. • The spray pyrolysis technique is of low cost and scalable for industrial applications. • We obtained deposition rate of 60 nm min{sup −1} at 300 °C. • The average resistivity was 1E−7 Ω m. • Semi-transparent silver films were obtained at 350 °C and deposition time of 45 s. -- Abstract: The synthesis and characterization of nanostructured silver films deposited on corning glass by a deposition technique called Pneumatically-Assisted Ultrasonic Spray Pyrolysis are reported. Silver nitrate and triethanolamine were used as silver precursor and reducer agent, respectively. The substrate temperatures during deposition were in the range of 300–450 °C and the deposition times from 30 to 240 s. The deposited films are polycrystalline with cubic face-centered structure, and crystalline grain size less than 30 nm. Deposition rates up to 600 Å min{sup −1} were obtained at substrate temperature as low as 300 °C. The electrical, optical, and morphological properties of these films are also reported. Semi-transparent conductive silver films were obtained at 350 °C with a deposition time of 45 s.

  10. Synthesis of conductive semi-transparent silver films deposited by a Pneumatically-Assisted Ultrasonic Spray Pyrolysis Technique

    International Nuclear Information System (INIS)

    Zaleta-Alejandre, E.; Balderas-Xicoténcatl, R.; Arrieta, M.L. Pérez; Meza-Rocha, A.N.; Rivera-Álvarez, Z.; Falcony, C.

    2013-01-01

    Highlights: • We deposited metallic silver films without post-deposition annealing. • The spray pyrolysis technique is of low cost and scalable for industrial applications. • We obtained deposition rate of 60 nm min −1 at 300 °C. • The average resistivity was 1E−7 Ω m. • Semi-transparent silver films were obtained at 350 °C and deposition time of 45 s. -- Abstract: The synthesis and characterization of nanostructured silver films deposited on corning glass by a deposition technique called Pneumatically-Assisted Ultrasonic Spray Pyrolysis are reported. Silver nitrate and triethanolamine were used as silver precursor and reducer agent, respectively. The substrate temperatures during deposition were in the range of 300–450 °C and the deposition times from 30 to 240 s. The deposited films are polycrystalline with cubic face-centered structure, and crystalline grain size less than 30 nm. Deposition rates up to 600 Å min −1 were obtained at substrate temperature as low as 300 °C. The electrical, optical, and morphological properties of these films are also reported. Semi-transparent conductive silver films were obtained at 350 °C with a deposition time of 45 s

  11. Magneto-optical properties of semi-parabolic plus semi-inverse squared quantum wells

    Science.gov (United States)

    Tung, Luong V.; Vinh, Pham T.; Phuc, Huynh V.

    2018-06-01

    We theoretically study the optical absorption in a quantum well with the semi-parabolic potential plus the semi-inverse squared potential (SPSIS) in the presence of a static magnetic field in which both one- and two-photon absorption processes have been taken into account. The expression of the magneto-optical absorption coefficient (MOAC) is expressed by the second-order golden rule approximation including the electron-LO phonon interaction. We also use the profile method to obtain the full width at half maximum (FWHM) of the absorption peaks. Our numerical results show that either MOAC or FWHM strongly depends on the confinement frequency, temperature, and magnetic field but their dependence on the parameter β is very weak. The temperature dependence of FWHM is consistent with the previous theoretical and experimental works.

  12. Liquid state behaviour of semi-conducting materials; Comportement a l'etat liquide des materiaux semiconducteurs

    Energy Technology Data Exchange (ETDEWEB)

    Vandevyver, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    This work is a review of the present state of knowledge concerning the behaviour in the liquid state of materials having semi-conducting properties in the solid state. In the case of many materials it is observed that a 'short-distance order' persists (with modifications) at temperatures above the melting point; this phenomenon is responsible for the semi-conducting properties of certain liquids. A decrease in the mobility of the carriers is generally observed on fusion, whereas the width of the forbidden zone increases: {delta}E{sub g} = {delta}E{sub g1} + {delta}E{sub g2}; {delta}E{sub g1} which is related to the expansion of the crystal is usually positive whereas {delta}E{sub g2} which is related to a change in the short-distance order is negative. According to the relative importance of these two phenomena, {delta}E{sub g} is either positive or negative, involving an increase or a decrease in the semiconducting nature of the material at its melting point. Various examples are presented, in particular that of selenium-tellurium solutions. The experimental study of the electrical properties of liquids comes up against major difficulties (the Hall effect in particular). It is shown nevertheless that the theoretical studies explain semi-quantitatively the known experimental results. (author) [French] Cette etude fait le point sur l'etat actuel des connaissances relatives au comportement a l'etat liquide des materiaux presentant a l'etat solide des proprietes semiconductrices. Dans de nombreux materiaux on observe la persistance (avec modification), d'un 'ordre a courte distance' a des temperatures superieures a celles de la fusion; ceci est a l'origine des proprietes semiconductrices de certains liquides. A la fusion on observe generalement une diminution de la mobilite des porteurs tandis que la largeur de la bande interdite subit un accroissement: {delta}E{sub g} = {delta}E{sub g1} + {delta}E{sub g2}; {delta}E{sub g1

  13. Feasibility of a semi-automated method for cardiac conduction velocity analysis of high-resolution activation maps

    NARCIS (Netherlands)

    Doshi, Ashish N.; Walton, Richard D.; Krul, Sébastien P.; de Groot, Joris R.; Bernus, Olivier; Efimov, Igor R.; Boukens, Bastiaan J.; Coronel, Ruben

    2015-01-01

    Myocardial conduction velocity is important for the genesis of arrhythmias. In the normal heart, conduction is primarily dependent on fiber direction (anisotropy) and may be discontinuous at sites with tissue heterogeneities (trabeculated or fibrotic tissue). We present a semi-automated method for

  14. CO2 Absorption from Biogas by Glycerol: Conducted in Semi-Batch Bubble Column

    Science.gov (United States)

    puji lestari, Pratiwi; Mindaryani, Aswati; Wirawan, S. K.

    2018-03-01

    Biogas is a renewable energy source that has been developed recently. The main contents of Biogas itself are Methane and carbon dioxide (CO2) where Methane is the main component of biogas with CO2 as the highest impurities. The quality of biogas depends on the CO2 content, the lower CO2 levels, the higher biogas quality. Absorption is one of the methods to reduce CO2 level. The selections of absorbent and appropriate operating parameters are important factors in the CO2 absorption from biogas. This study aimed to find out the design parameters for CO2 absorption using glycerol that represented by the overall mass transfer coefficient (KLa) and Henry’s constant (H). This study was conducted in semi-batch bubble column. Mixed gas was contacted with glycerol in a bubble column. The concentration of CO2 in the feed gas inlet and outlet columns were analysed by Gas Chromatograph. The variables observed in this study were superficial gas velocity and temperatures. The results showed that higher superficial gas velocity and lower temperature increased the rate of absorption process and the amount of CO2 absorbed.

  15. CT pre-operative planning of a new semi-implantable bone conduction hearing device

    Energy Technology Data Exchange (ETDEWEB)

    Law, Eric K.C.; Bhatia, Kunwar S.S. [Prince of Wales Hospital, The Chinese University of Hong Kong, Department of Imaging and Interventional Radiology, Hong Kong, SAR (China); Tsang, Willis S.S.; Tong, Michael C.F. [Prince of Wales Hospital, The Chinese University of Hong Kong, Department of Otorhinolaryngology, Head and Neck Surgery, Hong Kong, SAR (China); Shi, Lin [The Chinese University of Hong Kong, Department of Medicine and Therapeutics, Hong Kong, SAR (China); The Chinese University of Hong Kong, Chow Yuk Ho Technology Center for Innovative Medicine, Hong Kong, SAR (China)

    2016-06-15

    Accommodating a novel semi-implantable bone conduction hearing device within the temporal bone presents challenges for surgical planning. This study describes the utility of CT in pre-operative assessment of such an implant. Retrospective review of pre-operative CT, clinical and surgical records of 16 adults considered for device implantation. Radiological suitability was assessed on CT using 3D simulation software. Antero-posterior (AP) dimensions of the mastoid bone and minimum skull thickness were measured. CT planning results were correlated with operative records. Eight and five candidates were suitable for device placement in the transmastoid and retrosigmoid positions, respectively, and three were radiologically unsuitable. The mean AP diameter of the mastoid cavity was 14.6 mm for the transmastoid group and 4.6 mm for the retrosigmoid group (p < 0.05). Contracted mastoid and/or prior surgery were predisposing factors for unsuitability. Four transmastoid and five retrosigmoid positions required sigmoid sinus/dural depression and/or use of lifts due to insufficient bone capacity. A high proportion of patients being considered have contracted or operated mastoids, which reduces the feasibility of the transmastoid approach. This finding combined with the complex temporal bone geometry illustrates the importance of careful CT evaluation using 3D software for precise device simulation. (orig.)

  16. 75 FR 78915 - Conduct on Postal Property

    Science.gov (United States)

    2010-12-17

    ... lottery ticket sales contains an exception for Randolph-Sheppard vendors. This exception is amended to... tickets ``for any lottery authorized by State law and conducted by an agency of a State''. This amendment... lottery or pool, or the selling or purchasing of lottery tickets, is prohibited on postal premises. In...

  17. Polyfuran Conducting Polymers: Synthesis, Properties, and Applications.

    OpenAIRE

    González-Tejera, M.J.; Sánchez de la Blanca, Emilia; Carrillo Ramiro, Isabel

    2008-01-01

    In this review, polyfuran (PFu) synthesis methods and the nucleation mechanism; the electrochemical, structural, morphological, and magnetic properties of PFu; thermal behavior; theoretical calculations on PFu, as well as its applications reported to date, have been compiled. Not only PFu homopolymers have been reviewed, but also PFu co-polymers, PFu bipolymers, and PFu composites. The results are listed, discussed, and compared. It is hoped that this assembly of all the relevant data might e...

  18. New membrane structures with proton conducting properties

    DEFF Research Database (Denmark)

    Nørgaard, Casper Frydendal

    if higher operating temperature is enabled. One approach to obtain improved membranes in the aspects of applicable operating temperature and methanol permeability, which has attracted considerable attention, is the formation of composites by distributing inorganic fillers into Nafion or alternative polymers...... temperature and high relative humidity can cause excessive swelling of the membranes, yielding insufficient mechanical properties and breakdown of membrane function. Moreover, in the case of the Direct Methanol Fuel Cell (DMFC), their significant methanol permeability causes loss of efficiency. Higher...

  19. Effect of fully and semi austempering treatment on the fatigue properties of ductile cast iron

    International Nuclear Information System (INIS)

    Kim, Min Gun; Lim, Bok Kyu; Hwang, Jung Gak; Kim, Dong Youl

    2005-01-01

    Single phase bainite structure which is obtained by the conventional austempering treatment reduces the ductility of ductile cast iron. Because of the reduction of ductility it is possible to worsen the fatigue properties. Therefore, semi austempered ductile iron which is treated from α+γ is prepared to investigate the static strength and fatigue properties in comparison with fully austempered ductile iron (is treated from γ). In spite of semi austempered ductile iron shows the 86% increase of ductility. Also, semi austempered ductile iron shows the higher fatigue limit and lower fatigue crack growth rate as compared with fully austempered ductile iron. By the fractographical analysis, it is revealed that the ferrite obtained by semi austempering process brings about the plastic deformation (ductile striation) of crack tip and gives the prior path of crack propagation. The relatively low crack growth rate in semi austempered specimen is caused by above fractographical reasons

  20. Thermal properties of conducting polypyrrole nanotubes

    Czech Academy of Sciences Publication Activity Database

    Rudajevová, A.; Varga, M.; Prokeš, J.; Kopecká, J.; Stejskal, Jaroslav

    2015-01-01

    Roč. 128, č. 4 (2015), s. 730-736 ISSN 0587-4246. [ISPMA 13 - International Symposium on Physics of Materials /13./. Praha, 31.08.2014-04.09.2014] R&D Projects: GA ČR(CZ) GA13-00270S Institutional support: RVO:61389013 Keywords : conducting polymer * polyaniline * polypyrrole Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.525, year: 2015

  1. PCL-PLLA Semi-IPN Shape Memory Polymers (SMPs): Degradation and Mechanical Properties.

    Science.gov (United States)

    Woodard, Lindsay N; Page, Vanessa M; Kmetz, Kevin T; Grunlan, Melissa A

    2016-12-01

    Thermoresponsive shape memory polymers (SMPs) based on poly(ε-caprolactone) (PCL) whose shape may be actuated by a transition temperature (T trans ) have shown utility for a variety of biomedical applications. Important to their utility is the ability to modulate mechanical and degradation properties. Thus, in this work, SMPs are formed as semi-interpenetrating networks (semi-IPNs) comprised of a cross-linked PCL diacrylate (PCL-DA) network and thermoplastic poly(l-lactic acid) (PLLA). The semi-IPN uniquely allows for requisite crystallization of both PCL and PLLA. The influence of PLLA (PCL:PLLA wt% ratio) and PCL-DA molecular weight (n) on film properties are investigated. PCL-PLLA semi-IPNs are able to achieve enhanced mechanical properties and accelerated rates of degradation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Thermal Properties of Asphalt Mixtures Modified with Conductive Fillers

    Directory of Open Access Journals (Sweden)

    Byong Chol Bai

    2015-01-01

    Full Text Available This paper investigates the thermal properties of asphalt mixtures modified with conductive fillers used for snow melting and solar harvesting pavements. Two different mixing processes were adopted to mold asphalt mixtures, dry- and wet-mixing, and two conductive fillers were used in this study, graphite and carbon black. The thermal conductivity was compared to investigate the effects of asphalt mixture preparing methods, the quantity, and the distribution of conductive filler on thermal properties. The combination of conductive filler with carbon fiber in asphalt mixture was evaluated. Also, rheological properties of modified asphalt binders with conductive fillers were measured using dynamic shear rheometer and bending beam rheometer at grade-specific temperatures. Based on rheological testing, the conductive fillers improve rutting resistance and decrease thermal cracking resistance. Thermal testing indicated that graphite and carbon black improve the thermal properties of asphalt mixes and the combined conductive fillers are more effective than the single filler.

  3. Proton conducting semi-IPN based on Nafion and crosslinked poly(AMPS) for direct methanol fuel cell

    International Nuclear Information System (INIS)

    Cho, Ki-Yun; Jung, Ho-Young; Shin, Seung-Shik; Choi, Nam-Soon; Sung, Shi-Joon; Park, Jung-Ki; Choi, Jong-Ho; Park, Kyung-Won; Sung, Yung-Eun

    2004-01-01

    For direct methanol fuel cell, the proton conducting membrane based on semi-interpenetrating polymer networks (IPNs) of Nafion and crosslinked poly(AMPS) was prepared and characterized. The modification of Nafion with crosslinked poly(AMPS) such as hydrocarbon polymer changed the state of water in membranes. Without a significant increase of the membrane resistance, the semi-IPNs demonstrated a reduction of the methanol permeability, comparing to the native Nafion. And the maximum power density of AMPS60 increased as much as 22.2% compared with Nafion

  4. Studies on aerosol optical properties over urban and semi-urban environments of Hyderabad and Anantapur

    International Nuclear Information System (INIS)

    Lata, K.M.; Badarinath, K.V.S.; Rao, T.V. Ramakrishna; Reddy, R.R.; Ahammed, Y. Nazeer; Gopal, K. Rama; Azeem, P. Abdul

    2003-01-01

    Aerosols in the troposphere exert an important influence on global climate and the environment through scattering, transmission and absorption of radiation as well as acting as nuclei for cloud formation. Atmospheric aerosol particles influence the earth's radiation balance directly by scattering of infrared energy and indirectly by modifying the properties of clouds through microphysical processes. The present study addresses visibility, radiative forcing, size distribution and attenuation of aerosols over the period from January to May, 2001 for urban and semi-urban regions of Hyderabad and Anantapur. High aerosol loading has been observed over urban environment compared to semi-urban environment. Aerosol optical depth values increased from January to April and then decreased during May over both urban and semi-urban regions. Over urban region, visibility decreased from January to April and increased during May. Similar trend has been observed over semi-urban region with relatively higher values of visibility. Radiative forcing estimated using aerosol optical depth values increased from January to April and then decreased during the month of May over urban and semi-urban areas. High visibility and low radiative forcing has been noticed over semi-urban area due to less aerosol loading. Wavelength exponent and turbidity coefficient registered high values over urban environment compared to semi-urban environment. Attenuation coefficient showed high values over urban region compared to semi-urban region. It reveals that semi-urban environment receives high solar flux than urban environment. Using 10 channel quartz crystal microbalance, measurements of total mass concentration and mass size distribution of near surface aerosols has been made over semi-urban environment and compared with size distribution derived from inversion methods based on aerosol optical depth variation with wavelength. The sensitivity of constrained linear inversions for inferring columnar

  5. Tribological properties of rice starch in liquid and semi-solid food model systems

    NARCIS (Netherlands)

    Liu, K.; Stieger, M.A.; Linden, van der E.; Velde, van de Fred

    2016-01-01

    This study investigated the tribological and rheological properties of liquid and semi-solid food model systems containing micro-granular rice starch. Native (uncooked) and gelatinized rice starch dispersions, o/w emulsions and emulsion-filled gelatin gels were studied as food model systems. Native

  6. Characterization and swelling-deswelling properties of wheat straw cellulose based semi-IPNs hydrogel.

    Science.gov (United States)

    Liu, Jia; Li, Qian; Su, Yuan; Yue, Qinyan; Gao, Baoyu

    2014-07-17

    A novel wheat straw cellulose-g-poly(potassium acrylate)/polyvinyl alcohol (WSC-g-PKA/PVA) semi-interpenetrating polymer networks (semi-IPNs) hydrogel was prepared by polymerizing wheat straw and an aqueous solution of acrylic acid (AA), and further semi-interpenetrating with PVA occurred during the chemosynthesis. The swelling and deswelling properties of WSC-g-PKA/PVA semi-IPNs hydrogel and WSC-g-PKA hydrogel were studied and compared in various pH solutions, salt solutions, temperatures, particle sizes and ionic strength. The results indicated that both hydrogels had the largest swelling capacity at pH=6, and the effect of ions on the swelling of hydrogels was in the order: Na(+)>K(+)>Mg(2+)>Ca(2+). The Schott's pseudo second order model can be effectively used to evaluate swelling kinetics of hydrogels. Moreover, the semi-IPNs hydrogel had improved swelling-deswelling properties compared with that of WSC-g-PKA hydrogel. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Properties of solutions in semi-hyperbolic patches for unsteady transonic small disturbance equations

    Directory of Open Access Journals (Sweden)

    Ilija Jegdic

    2015-09-01

    Full Text Available We consider a two-dimensional Riemann problem for the unsteady transonic small disturbance equation resulting in diverging rarefaction waves. We write the problem in self-similar coordinates and we obtain a mixed type (hyperbolic-elliptic system. Resolving the one-dimensional discontinuities in the far field, where the system is hyperbolic, and using characteristics, we formulate the problem in a semi-hyperbolic patch that is between the hyperbolic and the elliptic regions. A semi-hyperbolic patch is known as a region where one family out of two nonlinear families of characteristics starts on a sonic curve and ends on a transonic shock. We obtain existence of a smooth local solution in this semi-hyperbolic patch and we prove various properties of global smooth solutions based on a characteristic decomposition using directional derivatives.

  8. Semi-conducting material obtained from natural fiber modified with PAni

    International Nuclear Information System (INIS)

    Rocha, Eli V. da; Silva Junior, Fernando Gomes; Oliveira, Geiza E.; Pinto, Jose Carlos

    2009-01-01

    The surface of natural Brazilian Amazonic fibers (curaua, Ananas erectifolius) was modified with polyaniline nanoparticles, through in-situ preparation of polyaniline nanoparticles in presence of the curaua fibers. As it was shown here, this modification allowed a very significant increase of the electrical conductivity of the fibers (about 2.500 times). The modified materials were also characterized by FTIR (Fourier Transform Infrared Spectroscopy), AFM (Atomic Force Microscopy) and SAXS (Small Angle X-ray Scattering) and the obtained results were used to explain some of the chemical and morphological aspects of the materials. (author)

  9. Semi-degradable poly(β-amino ester) networks with temporally controlled enhancement of mechanical properties.

    Science.gov (United States)

    Safranski, David L; Weiss, Daiana; Clark, J Brian; Taylor, W Robert; Gall, Ken

    2014-08-01

    Biodegradable polymers are clinically used in numerous biomedical applications, and classically show a loss of mechanical properties within weeks of implantation. This work demonstrates a new class of semi-degradable polymers that show an increase in mechanical properties through degradation via a controlled shift in a thermal transition. Semi-degradable polymer networks, poly(β-amino ester)-co-methyl methacrylate, were formed from a low glass transition temperature crosslinker, poly(β-amino ester), and high glass transition temperature monomer, methyl methacrylate, which degraded in a manner dependent upon the crosslinker chemical structure. In vitro and in vivo degradation revealed changes in mechanical behavior due to the degradation of the crosslinker from the polymer network. This novel polymer system demonstrates a strategy to temporally control the mechanical behavior of polymers and to enhance the initial performance of smart biomedical devices. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  10. Analytical Evalution of Heat Transfer Conductivity with Variable Properties

    DEFF Research Database (Denmark)

    Rahimi, Masoume; Hosseini, Mohammad Javad; Barari, Amin

    2011-01-01

    The homotopy analysis method (HAM) as a new technique which is powerful and easy-to-use, is applied to solve heat transfer problems. In this paper, we use HAM for heat transfer conductivity equation with variable properties which may contain highly nonlinear terms. The obtained results are also...

  11. Electromagnetic properties of conducting polymers encapsulated in an insulating matrix

    International Nuclear Information System (INIS)

    Esnouf, Stephane

    1995-01-01

    The aim of this work is to study the electronic properties of conducting polymers encapsulated in zeolite. We studied two kinds of polymers: intrinsic conducting polymers (poly-pyrrole) and pyrolyzed polymers (polyacrylonitrile and poly-furfuryl alcohol). These systems were characterized by electron paramagnetic resonance and microwave conductivity measurements. In the first part, we present the preparation and the characterization of encapsulated poly-pyrrole. Conductivity measurements show that the encapsulated material is insulating, certainly because a strong interaction with the zeolite traps the charge carriers. In the second part, we focus on pyrolyzed encapsulated polyacrylonitrile. This system has a metal-like susceptibility at room temperature and a relatively high microwave conductivity. These results demonstrate the formation during the pyrolysis of extended aromatic clusters. Finally, we study pyrolyzed encapsulated poly-furfuryl alcohol. We show that the only effect of the pyrolysis is to fragment the polymers. We also discuss the spin relaxation and the EPR line broadening. (author) [fr

  12. Visualizing One-Dimensional Electronic States and their Scattering in Semi-conducting Nanowires

    Science.gov (United States)

    Beidenkopf, Haim; Reiner, Jonathan; Norris, Andrew; Nayak, Abhay Kumar; Avraham, Nurit; Shtrikman, Hadas

    One-dimensional electronic systems constitute a fascinating playground for the emergence of exotic electronic effects and phases, within and beyond the Tomonaga-Luttinger liquid paradigm. More recently topological superconductivity and Majorana modes were added to that long list of phenomena. We report scanning tunneling microscopy and spectroscopy measurements conducted on pristine, epitaxialy grown InAs nanowires. We resolve the 1D electronic band structure manifested both via Van-Hove singularities in the local density-of-states, as well as by the quasi-particle interference patterns, induced by scattering from surface impurities. By studying the scattering of the one-dimensional electronic states off various scatterers, including crystallographic defects and the nanowire end, we identify new one-dimensional relaxation regimes and yet unexplored effects of interactions. Some of these may bear implications on the topological superconducting state and Majorana modes therein. The authors acknowledge support from the Israeli Science Foundation (ISF).

  13. Electric properties of semi-insulating crystals CdTe:Cl

    International Nuclear Information System (INIS)

    Arkadyeva, E.N.; Matveev, O.A.

    1977-01-01

    Hall effect and conductivity measurement were carried out on chlorine doped semi-insulating CdTe crystals, of p and n electric type. In p type crystals the depth of the dominating level was determined (+0.7eV) as well as the concentration of associated centres (10 13 -10 14 cm -3 ). The mobility values are limited by a process of diffusion on heterogeneities

  14. Viscosity, Conductivity, and Electrochemical Property of Dicyanamide Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Wen-Li Yuan

    2018-03-01

    Full Text Available The instructive structure-property relationships of ionic liquids (ILs can be put to task-specific design of new functionalized ILs. The dicyanamide (DCA ILs are typical CHN type ILs which are halogen free, chemical stable, low-viscous, and fuel-rich. The transport properties of DCA ionic liquids are significant for their applications as solvents, electrolytes, and hypergolic propellants. This work systematically investigates several important transport properties of four DCA ILs ([C4mim][N(CN2], [C4m2im][N(CN2], N4442[N(CN2], and N8444[N(CN2] including viscosity, conductivity, and electrochemical property at different temperatures. The melting points, temperature-dependent viscosities and conductivities reveal the structure-activity relationship of four DCA ILs. From the Walden plots, the imidazolium cations exhibit stronger cation–anion attraction than the ammonium cations. DCA ILs have relatively high values of electrochemical windows (EWs, which indicates that the DCA ILs are potential candidates for electrolytes in electrochemical applications. The cyclic voltammograms of Eu(III in these DCA ILs at GC working electrode at various temperatures 303–333 K consists of quasi-reversible waves. The electrochemical properties of the DCA ILs are also dominated by the cationic structures. The current intensity (ip, the diffusion coefficients (Do, the charge transfer rate constants (ks of Eu(III in DCA ILs all increased with the molar conductivities increased. The cationic structure-transport property relationships of DCA ILs were constructed for designing novel functionalized ILs to fulfill specific demands.

  15. Proton conductivity and relaxation properties of chitosan-acetate films

    International Nuclear Information System (INIS)

    Prokhorov, E.; Luna-Bárcenas, G.; González-Campos, J.B.; Kovalenko, Yu.; García-Carvajal, Z.Y.; Mota-Morales, J.

    2016-01-01

    Graphical abstract: Temperature dependence of conductivity, the number of density and proton mobility in chitosan-acetate film. - Highlights: • DD, conductivity, Vogel temperature dependent on the concentration of acetic acid. • Proton conductivity of CS-acetate films interpreted using two Grotthuss mechanisms. • Transformation between two mechanisms observed at the glass transition temperature. - Abstract: The effect of aqueous acetic acid solution concentration during the preparation of chitosan-acetate (CS-acetate) films on the conductivity and relaxation properties were studied by dielectric and FTIR spectroscopies, TGA measurements and X-Ray diffraction. Analyses of the experimental results on the degree of deacetylation, water absorption, conductivity, Vogel temperature and activation energy demonstrate a strong dependence of these parameters on the concentration of the acid acetic solutions from which the films have been obtained. The proton conductivity and relaxation properties of CS-acetate films have been interpreted using two Grotthuss “structural diffusion” and “pack-acid” mechanisms. The transformation between these two mechanisms observed at temperature higher than CS-acetate glass transition temperature is due to an increase in the thermal motion of CS chains, water evaporation, hydrogen bond between water molecules and side groups of CS breaking and formation of new bonds between NH 3 + and acetate ions. Additionally, application of the Rice and Roth model allowed estimating the temperature dependence of proton number and their mobility in CS-acetate films. A systematic interpretation on the appropriate conductivity mechanism will help trigger the design of smart materials used in flexible electronic, solid polymer electrolytes for fuel cells and solid polymer batteries based on CS-acetate films.

  16. Predicting saturated hydraulic conductivity using soil morphological properties

    Directory of Open Access Journals (Sweden)

    Gülay Karahan

    2016-01-01

    Full Text Available Many studies have been conducted to predict soil saturated hydraulic conductivity (Ks by parametric soil properties such as bulk density and particle-size distribution. Although soil morphological properties have a strong effect on Ks, studies predicting Ks by soil morphological properties such as type, size, and strength of soil structure; type, orientation and quantity of soil pores and roots and consistency are rare. This study aimed at evaluating soil morphological properties to predict Ks. Undisturbed soil samples (15 cm length and 8.0 cm id. were collected from topsoil (0-15 cm and subsoil (15-30 cm (120 samples with a tractor operated soil sampler at sixty randomly selected sampling sites on a paddy field and an adjecent grassland in Central Anatolia (Cankırı, Turkey. Synchronized disturbed soil samples were taken from the same sampling sites and sampling depths for basic soil analyses. Saturated hydraulic conductivity was measured on the soil columns using a constant-head permeameter. Following the Ks measurements, the upper part of soil columns were covered to prevent evaporation and colums were left to drain in the laboratory. When the water flow through the column was stopped, a subsample were taken for bulk density and then soil columns were disturbed for describing the soil morphological properties. In addition, soil texture, bulk density, pH, field capacity, wilting point, cation exchange capacity, specific surface area, aggregate stability, organic matter, and calcium carbonate were measured on the synchronized disturbed soil samples. The data were divided into training (80 data values and validation (40 data values sets. Measured values of Ks ranged from 0.0036 to 2.14 cmh-1 with a mean of 0.86 cmh-1. The Ks was predicted from the soil morphological and parametric properties by stepwise multiple linear regression analysis. Soil structure class, stickiness, pore-size, root-size, and pore-quantity contributed to the Ks prediction

  17. Thermophysical Properties of Liquid Te: Density, Electrical Conductivity, and Viscosity

    Science.gov (United States)

    Li, C.; Su, C.; Lehoczky, S. L.; Scripa, R. N.; Ban, H.; Lin, B.

    2004-01-01

    The thermophysical properties of liquid Te, namely, density, electrical conductivity, and viscosity, were determined using the pycnometric and transient torque methods from the melting point of Te (723 K) to approximately 1150 K. A maximum was observed in the density of liquid Te as the temperature was increased. The electrical conductivity of liquid Te increased to a constant value of 2.89 x 10(exp 5 OMEGA-1m-1) as the temperature was raised above 1000 K. The viscosity decreased rapidly upon heating the liquid to elevated temperatures. The anomalous behaviors of the measured properties are explained as caused by the structural transitions in the liquid and discussed in terms of Eyring's and Bachiskii's predicted behaviors for homogeneous liquids. The Properties were also measured as a function of time after the liquid was coded from approximately 1173 or 1123 to 823 K. No relaxation phenomena were observed in the properties after the temperature of liquid Te was decreased to 823 K, in contrast to the relaxation behavior observed for some of the Te compounds.

  18. Transport properties of olivine grain boundaries from electrical conductivity experiments

    Science.gov (United States)

    Pommier, Anne; Kohlstedt, David L.; Hansen, Lars N.; Mackwell, Stephen; Tasaka, Miki; Heidelbach, Florian; Leinenweber, Kurt

    2018-05-01

    Grain boundary processes contribute significantly to electronic and ionic transports in materials within Earth's interior. We report a novel experimental study of grain boundary conductivity in highly strained olivine aggregates that demonstrates the importance of misorientation angle between adjacent grains on aggregate transport properties. We performed electrical conductivity measurements of melt-free polycrystalline olivine (Fo90) samples that had been previously deformed at 1200 °C and 0.3 GPa to shear strains up to γ = 7.3. The electrical conductivity and anisotropy were measured at 2.8 GPa over the temperature range 700-1400 °C. We observed that (1) the electrical conductivity of samples with a small grain size (3-6 µm) and strong crystallographic preferred orientation produced by dynamic recrystallization during large-strain shear deformation is a factor of 10 or more larger than that measured on coarse-grained samples, (2) the sample deformed to the highest strain is the most conductive even though it does not have the smallest grain size, and (3) conductivity is up to a factor of 4 larger in the direction of shear than normal to the shear plane. Based on these results combined with electrical conductivity data for coarse-grained, polycrystalline olivine and for single crystals, we propose that the electrical conductivity of our fine-grained samples is dominated by grain boundary paths. In addition, the electrical anisotropy results from preferential alignment of higher-conductivity grain boundaries associated with the development of a strong crystallographic preferred orientation of the grains.

  19. Microwave conductance properties of aligned multiwall carbon nanotube textile sheets

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Brian L. [Univ. of Texas, Dallas, TX (United States); Martinez, Patricia [Univ. of Texas, Dallas, TX (United States); Zakhidov, Anvar A. [Univ. of Texas, Dallas, TX (United States); Shaner, Eric A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lee, Mark [Univ. of Texas, Dallas, TX (United States)

    2015-07-06

    Understanding the conductance properties of multi-walled carbon nanotube (MWNT) textile sheets in the microwave regime is essential for their potential use in high-speed and high-frequency applications. To expand current knowledge, complex high-frequency conductance measurements from 0.01 to 50 GHz and across temperatures from 4.2 K to 300 K and magnetic fields up to 2 T were made on textile sheets of highly aligned MWNTs with strand alignment oriented both parallel and perpendicular to the microwave electric field polarization. Sheets were drawn from 329 and 520 μm high MWNT forests that resulted in different DC resistance anisotropy. For all samples, the microwave conductance can be modeled approximately by a shunt capacitance in parallel with a frequency-independent conductance, but with no inductive contribution. Finally, this is consistent with diffusive Drude conduction as the primary transport mechanism up to 50 GHz. Further, it is found that the microwave conductance is essentially independent of both temperature and magnetic field.

  20. Structural, ac conductivity and dielectric properties of 3-formyl chromone

    Science.gov (United States)

    Ali, H. A. M.

    2017-07-01

    The structure for the powder of 3-formyl chromone was examined by X-ray diffraction technique in the 2θ° range ( 4° - 60° . The configuration of Al/3-formyl chromone/Al samples was designed. The electrical and dielectric properties were studied as a function of frequency (42- 5 × 106 Hz) and temperature (298-408K). The ac conductivity data of bulk of 3-formyl chromone varies as a power law with the frequency at different temperatures. The predominant mechanism for ac conduction was deduced. The ac conductivity shows a thermally activated process at different frequencies. The dielectric constant and dielectric loss were determined using the capacitance and dissipation factor measurements at different temperatures. The dielectric loss shows a peak of relaxation time that shifted to higher frequency with an increase in the temperature. The activation energy of the relaxation process was estimated.

  1. Thermophysical properties of fluids: dynamic viscosity and thermal conductivity

    Science.gov (United States)

    Latini, G.

    2017-11-01

    Thermophysical properties of fluids strongly depend upon atomic and molecular structure, complex systems governed by physics laws providing the time evolution. Theoretically the knowledge of the initial position and velocity of each atom, of the interaction forces and of the boundary conditions, leads to the solution; actually this approach contains too many variables and it is generally impossible to obtain an acceptable solution. In many cases it is only possible to calculate or to measure some macroscopic properties of fluids (pressure, temperature, molar volume, heat capacities...). The ideal gas “law,” PV = nRT, was one of the first important correlations of properties and the deviations from this law for real gases were usefully proposed. Moreover the statistical mechanics leads for example to the “hard-sphere” model providing the link between the transport properties and the molecular size and speed of the molecules. Further approximations take into account the intermolecular interactions (the potential functions) which can be used to describe attractions and repulsions. In any case thermodynamics reduces experimental or theoretical efforts by relating one physical property to another: the Clausius-Clapeyron equation provides a classical example of this method and the PVT function must be known accurately. However, in spite of the useful developments in molecular theory and computers technology, often it is usual to search for physical properties when the existing theories are not reliable and experimental data are not available: the required value of the physical or thermophysical property must be estimated or predicted (very often estimation and prediction are improperly used as synonymous). In some cases empirical correlations are useful, if it is clearly defined the range of conditions on which they are based. This work is concerned with dynamic viscosity µ and thermal conductivity λ and is based on clear and important rules to be respected

  2. Research Note:Determination of soil hydraulic properties using pedotransfer functions in a semi-arid basin, Turkey

    Directory of Open Access Journals (Sweden)

    M. Tombul

    2004-01-01

    Full Text Available Spatial and temporal variations in soil hydraulic properties such as soil moisture q(h and hydraulic conductivity K(q or K(h, may affect the performance of hydrological models. Moreover, the cost of determining soil hydraulic properties by field or laboratory methods makes alternative indirect methods desirable. In this paper, various pedotransfer functions (PTFs are used to estimate soil hydraulic properties for a small semi-arid basin (Kurukavak in the north-west of Turkey. The field measurements were a good fit with the retention curve derived using Rosetta SSC-BD for a loamy soil. To predict parameters to describe soil hydraulic characteristics, continuous PTFs such as Rosetta SSC-BD (Model H3 and SSC-BD-q33q1500 (Model H5 have been applied. Using soil hydraulic properties that vary in time and space, the characteristic curves for three soil types, loam, sandy clay loam and sandy loam have been developed. Spatial and temporal variations in soil moisture have been demonstrated on a plot and catchment scale for loamy soil. It is concluded that accurate site-specific measurements of the soil hydraulic characteristics are the only and probably the most promising method to progress in the future. Keywords: soil hydraulic properties, soil characteristic curves, PTFs

  3. Prediction of Physicochemical Properties of Organic Molecules Using Semi-Empirical Methods

    International Nuclear Information System (INIS)

    Kim, Chan Kyung; Kim, Chang Kon; Kim, Miri; Lee, Hai Whang; Cho, Soo Gyeong

    2013-01-01

    Prediction of physicochemical properties of organic molecules is an important process in chemistry and chemical engineering. The MSEP approach developed in our lab calculates the molecular surface electrostatic potential (ESP) on van der Waals (vdW) surfaces of molecules. This approach includes geometry optimization and frequency calculation using hybrid density functional theory, B3LYP, at the 6-31G(d) basis set to find minima on the potential energy surface, and is known to give satisfactory QSPR results for various properties of organic molecules. However, this MSEP method is not applicable to screen large database because geometry optimization and frequency calculation require considerable computing time. To develop a fast but yet reliable approach, we have re-examined our previous work on organic molecules using two semi-empirical methods, AM1 and PM3. This new approach can be an efficient protocol in designing new molecules with improved properties

  4. Scattering and radiative properties of semi-external versus external mixtures of different aerosol types

    International Nuclear Information System (INIS)

    Mishchenko, Michael I.; Liu Li; Travis, Larry D.; Lacis, Andrew A.

    2004-01-01

    The superposition T-matrix method is used to compute the scattering of unpolarized light by semi-external aerosol mixtures in the form of polydisperse, randomly oriented two-particle clusters with touching components. The results are compared with those for composition-equivalent external aerosol mixtures, in which the components are widely separated and scatter light in isolation from each other. It is concluded that aggregation is likely to have a relatively weak effect on scattering and radiative properties of two-component tropospheric aerosols and can be replaced by the much simpler external-mixture model in remote sensing studies and atmospheric radiation balance computations

  5. High accuracy thermal conductivity measurement of aqueous cryoprotective agents and semi-rigid biological tissues using a microfabricated thermal sensor

    Science.gov (United States)

    Liang, Xin M.; Sekar, Praveen K.; Zhao, Gang; Zhou, Xiaoming; Shu, Zhiquan; Huang, Zhongping; Ding, Weiping; Zhang, Qingchuan; Gao, Dayong

    2015-01-01

    An improved thermal-needle approach for accurate and fast measurement of thermal conductivity of aqueous and soft biomaterials was developed using microfabricated thermal conductivity sensors. This microscopic measuring device was comprehensively characterized at temperatures from 0 °C to 40 °C. Despite the previous belief, system calibration constant was observed to be highly temperature-dependent. Dynamic thermal conductivity response during cooling (40 °C to –40 °C) was observed using the miniaturized single tip sensor for various concentrations of CPAs, i.e., glycerol, ethylene glycol and dimethyl sulfoxide. Chicken breast, chicken skin, porcine limb, and bovine liver were assayed to investigate the effect of anatomical heterogeneity on thermal conductivity using the arrayed multi-tip sensor at 20 °C. Experimental results revealed distinctive differences in localized thermal conductivity, which suggests the use of approximated or constant property values is expected to bring about results with largely inflated uncertainties when investigating bio-heat transfer mechanisms and/or performing sophisticated thermal modeling with complex biological tissues. Overall, the presented micro thermal sensor with automated data analysis algorithm is a promising approach for direct thermal conductivity measurement of aqueous solutions and soft biomaterials and is of great value to cryopreservation of tissues, hyperthermia or cryogenic, and other thermal-based clinical diagnostics and treatments. PMID:25993037

  6. Semi-Empirical Predictions on the Structure and Properties of ent-Kaurenoic Acid and Derivatives

    Directory of Open Access Journals (Sweden)

    Jose Isagani B. Janairo

    2011-01-01

    Full Text Available The physicochemical properties of ent- kaurenoic acid model derivatives, which possibly influence its therapeutic application, were calculated. Results revealed that the molecule possess favourable attributes which renders it possible to be considered as a drug lead only that its very hydrophobic nature can result to poor bioavailabilty, low absorption and poor systemic circulation. In silico simulations revealed that this setback can be overcome by introduction of hydroxyl group to the tertiary carbon of ent-kaurenoic acid employing m-CPBA catalyzed hydroxylation, thus, unleashing its full drug potency. Moreover, molecular similarity analyses derived from semi-empirical calculations between ent-kaurenoic acid and a set of kaurane diterpenoids showed differences in hydrophobic complementarity, size and electronic properties despite possessing nearly identical molecular frameworks, thus, arriving in a generalization for their observed mechanistic differences on acting on different targets.

  7. Semi-metallic polymers

    DEFF Research Database (Denmark)

    Bubnova, Olga; Khan, Zia Ullah; Wang, Hui

    2014-01-01

    Polymers are lightweight, flexible, solution-processable materials that are promising for low-cost printed electronics as well as for mass-produced and large-area applications. Previous studies demonstrated that they can possess insulating, semiconducting or metallic properties; here we report...... that polymers can also be semi-metallic. Semi-metals, exemplified by bismuth, graphite and telluride alloys, have no energy bandgap and a very low density of states at the Fermi level. Furthermore, they typically have a higher Seebeck coefficient and lower thermal conductivities compared with metals, thus being...... a Fermi glass to a semi-metal. The high Seebeck value, the metallic conductivity at room temperature and the absence of unpaired electron spins makes polymer semi-metals attractive for thermoelectrics and spintronics....

  8. Enhancing the piezoelectric properties of flexible hybrid AlN materials using semi-crystalline parylene

    Science.gov (United States)

    Jackson, Nathan; Mathewson, Alan

    2017-04-01

    Flexible piezoelectric materials are desired for numerous applications including biomedical, wearable, and flexible electronics. However, most flexible piezoelectric materials are not compatible with CMOS fabrication technology, which is desired for most MEMS applications. This paper reports on the development of a hybrid flexible piezoelectric material consisting of aluminium nitride (AlN) and a semi-crystalline polymer substrate. Various types of semi-crystalline parylene and polyimide materials were investigated as the polymer substrate. The crystallinity and surfaces of the polymer substrates were modified by micro-roughening and annealing in order to determine the effects on the AlN quality. The AlN crystallinity and piezoelectric properties decreased when the polymer surfaces were treated with O2 plasma. However, increasing the crystallinity of the parylene substrate prior to deposition of AlN caused enhanced c-axis (002) AlN crystallinity and piezoelectric response of the AlN. Piezoelectric properties of 200 °C annealed parylene-N substrate resulted in an AlN d 33 value of 4.87 pm V-1 compared to 2.17 pm V-1 for AlN on polyimide and 4.0 pm V-1 for unannealed AlN/parylene-N. The electrical response measurements to an applied force demonstrated that the parylene/AlN hybrid material had higher V pp (0.918 V) than commercial flexible piezoelectric material (PVDF) (V pp 0.36 V). The results in this paper demonstrate that the piezoelectric properties of a flexible AlN hybrid material can be enhanced by increasing the crystallinity of the polymer substrate, and the enhanced properties can function better than previous flexible piezoelectrics.

  9. Construction of a photovoltaic cell based on the photoelectrochemistry of organic dyes at transparent semi-conducting electrodes. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Nasielski, J; Kirsch-De Mesmaeker, A

    1982-01-01

    It is shown that the study of the photoelectrochemical mechanisms of different dye-reductant systems at transparent semi-conducting bubbling gas electrodes, coupled with a detailed analysis of the photovoltammetric curves, allows: a deeper insight into the operation principles of the corresponding dye photogalvanic cells; prediction of the parameters important for optimizing the cell operation; and working out of strategies for improving the cell output. In order to compare the behaviors of an adsorbed type dye (rhodamine-hydroquinone) with a solution type dye in a photogalvanic cell, the thionine-Fe/sup 2 +/ system was examined, including a detailed kinetic analysis of the photocurrents at the bubbling gas electrode as a function of several parameters. Photoelectrochemical mechanisms related to the sensitization and supersensitization in this system have thus been determined. Photoelectrochemical methods were applied to analyze other dye-reductant systems. The photoelectrochemisty of three triphenyl-methanes, methyl violet, crystal violet, and malachite green were examined at the bubbling gas electrode. These dyes produce photocurrents originating from the adsorbed molecules and behave very much like rhodamine. The photoelectrochemical behavior of the erythrosine-hydroquinone couple is also examined. For constructing photogalvanic cells, the CdS-on-SnO/sub 2/-cysteine system is found promising. (LEW)

  10. The Properties of Normal Conducting Cathodes in FZD Superconducting Gun

    CERN Document Server

    Xiang, R; Buettig, H; Janssen, D; Justus, M; Lehnert, U; Michel, P; Murcek, P; Schamlott, A; Schneider, Ch; Schurig, R; Staufenbiel, F; Teichert, J

    2009-01-01

    The superconducting radio frequency photoinjector (SRF photoinjector) is one of the latest applications of SC technology in the accelerator field. Since superconducting cathodes with high QE are not available up to now, normal conducting cathode material is the main choice for the SRF photoinjectors. However, the compatibility between the cathode and the cavity is one of the challenges for this concept. The SRF gun with Cs2Te cathode has been successfully operated under the collaboration of BESSY, DESY, FZD, and MBI. In this paper, some experience gained in the gun commissioning will be concluded. The results of the properties of Cs2Te photocathode in the cavity will be presented, such as the Q.E., the life time, the dark current and the thermal emittance.

  11. Development of spatial heterogeneity in vegetation and soil properties after land abandonment in a semi-arid ecosystem

    NARCIS (Netherlands)

    Lesschen, J.P.; Cammeraat, L.H.; Kooijman, A.M.; van Wesemael, B.

    2008-01-01

    To mitigate erosion on abandoned fields in semi-arid ecosystems, it is important to understand how vegetation and soil properties and patterns develop after land abandonment. Our objective was to investigate the development of spatial heterogeneity in vegetation and soil properties after land

  12. Thermoelectric properties of fully hydrogenated graphene: Semi-classical Boltzmann theory

    International Nuclear Information System (INIS)

    Reshak, A. H.

    2015-01-01

    Based on the calculated band structure, the electronic transport coefficients of chair-/boat-like graphane were evaluated by using the semi-classical Boltzmann theory and rigid band model. The maximum value of electrical conductivity for chair (boat)-like graphane of about 1.4 (0.6) × 10 19 (Ωms) −1 is achieved at 600 K. The charge carrier concentration and the electrical conductivity linearly increase with increasing the temperature in agreement with the experimental work for graphene. The investigated materials exhibit the highest value of Seebeck coefficient at 300 K. We should emphasize that in the chemical potential between ∓0.125 μ(eV) the investigated materials exhibit minimum value of electronic thermal conductivity, therefore, maximum efficiency. As the temperature increases, the electronic thermal conductivity increases exponentially, in agreement with the experimental data of graphene. We also calculated the power factor of chair-/boat-like graphane at 300 and 600 K as a function of chemical potential between ∓0.25 μ(eV)

  13. Life test of DMFC using poly(ethylene glycol)bis(carboxymethyl)ether plasticized PVA/PAMPS proton-conducting semi-IPNs

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, Jinli [National Institute of Advanced Industrial Science and Technology, Higashi 1-1-1, Central 5, Tsukuba, Ibaraki 305-8565 (Japan); New Energy Technology Research Center, Tongji University, Shanghai 201804 (China); Ikesaka, Shinya; Saito, Morihiro; Kuwano, Jun [Department of Industrial Chemistry, Faculty of Engineering, Tokyo University of Science, 12-1 Ichigayafunagawara-machi, Shinjuku-ku, Tokyo 162-0826 (Japan); Okada, Tatsuhiro [National Institute of Advanced Industrial Science and Technology, Higashi 1-1-1, Central 5, Tsukuba, Ibaraki 305-8565 (Japan)

    2007-08-15

    A novel, low-cost proton-conducting semi-IPN (semi-interpenetrating polymer network) has been successfully prepared from PVA/PAMPS (poly(vinyl alcohol) and poly(2-acrylamindo-2-methyl-1-propanesulfonic acid))blends by incorporating poly(ethylene glycol)bis(carboxymethyl)ether (PEGBCME) as a novel plasticizer. Although, the polymer is based on a relatively low content of PAMPS as a component of ion conducting sites, the resulting semi-IPN exhibited high proton conductivity (0.1 S cm{sup -1}) at 25 C, which afforded a higher power density of 51 mW cm{sup -2} at 80 C. A striking feature is that a long-term initial performance is achieved with a 130 h of stable fuel cell operation in DMFC mode due to effectively suppressed methanol crossover. This is a new record for a fully hydrocarbon membrane in DMFC, seeing that the PVA-PAMPS proton-conducting semi-IPNs are made simply of aliphatic skeletons. (author)

  14. Structure-Property Relationships in Amorphous Transparent Conducting Oxides

    Science.gov (United States)

    Moffitt, Stephanie Lucille

    Over the last 20 years a new field of amorphous transparent conducting oxides (a-TCOs) has developed. The amorphous nature of these films makes them well suited for large area applications. In addition, a-TCOs can be made at low temperatures and through solution processing methods. These assets provide promising opportunities to improve applications such as solar cells and back-lit displays where traditional crystalline TCOs are used. In addition, it opens the door for new technological applications including the possibility for transparent, flexible electronics. Despite the recent growth in this field, fundamental understanding of the true nature of conductivity and the amorphous structure in this materials system is still progressing. To develop a greater understanding of a-TCOs, structure-property relationships were developed in the a-IGO and a-IZO systems. From the combination of element-specific local structure studies and liquid quench molecular dynamics simulations it is clear that a degree of structure remains in a-TCOs. By understanding this structure, the effect of gallium on thermal stability, carrier concentration and carrier mobility is understood. The source of charge carriers in a-IZO is identified as oxygen vacancies through the application of in situ Brouwer analysis. The continued development of the Brouwer analysis technique for use in amorphous oxides adds to the available methods for studying defects in amorphous systems. Finally, the foundational knowledge gained from the in-depth study of a-IGO was extended to understand the role of combustion processing and pulsed laser deposition as growth methods for transistors based on a-IGO.

  15. Electrochemical Properties for Co-Doped Pyrite with High Conductivity

    Directory of Open Access Journals (Sweden)

    Yongchao Liu

    2015-09-01

    Full Text Available In this paper, the hydrothermal method was adopted to synthesize nanostructure Co-doped pyrite (FeS2. The structural properties and morphology of the synthesized materials were characterized using X-ray diffraction (XRD and scanning electron microscopy (SEM, respectively. Co in the crystal lattice of FeS2 could change the growth rate of different crystal planes of the crystal particles, which resulted in various polyhedrons with clear faces and sharp outlines. In addition, the electrochemical performance of the doping pyrite in Li/FeS2 batteries was evaluated using the galvanostatic discharge test, cyclic voltammetry and electrochemical impedance spectroscopy. The results showed that the discharge capacity of the doped material (801.8 mAh·g−1 with a doping ratio of 7% was significantly higher than that of the original FeS2 (574.6 mAh·g−1 because of the enhanced conductivity. Therefore, the doping method is potentially effective for improving the electrochemical performance of FeS2.

  16. Electrochromic properties of a novel low band gap conductive copolymer

    Energy Technology Data Exchange (ETDEWEB)

    Yigitsoy, Basak; Varis, Serhat; Tanyeli, Cihangir; Akhmedov, Idris M.; Toppare, Levent [Department of Chemistry, Middle East Technical University, 06531 Ankara (Turkey)

    2007-07-10

    A copolymer of 2,5-di(thiophen-2-yl)-1-p-tolyl-1H-pyrrole (DTTP) with 3,4-ethylene dioxythiophene (EDOT) was electrochemically synthesized. The resultant copolymer P(DTTP-co-EDOT) was characterized via cyclic voltammetry, FTIR, SEM, conductivity measurements and spectroelectrochemistry. Copolymer film has distinct electrochromic properties. It has four different colors (chestnut, khaki, camouflage green, and blue). At the neutral state {lambda}{sub max} due to the {pi}-{pi}{sup *} transition was found to be 487 nm and E{sub g} was calculated as 1.65 eV. Double potential step chronoamperometry experiment shows that copolymer film has good stability, fast switching time (less than 1 s) and good optical contrast (20%). An electrochromic device based on P(DTTP-co-EDOT) and poly(3,4-ethylenedioxythiophene) (PEDOT) was constructed and characterized. The device showed reddish brown color at -0.6 V when the P(DTTP-co-EDOT) layer was in its reduced state; whereas blue color at 2.0 V when PEDOT was in its reduced state and P(DTTP-co-EDOT) layer was in its oxidized state. At 0.2 V intermediate green state was observed. Maximum contrast (%{delta}T) and switching time of the device were measured as 18% and 1 s at 615 nm. ECD has good environmental and redox stability. (author)

  17. A semi-local quasi-harmonic model to compute the thermodynamic and mechanical properties of silicon nanostructures

    International Nuclear Information System (INIS)

    Zhao, H; Aluru, N R

    2007-01-01

    This paper presents a semi-local quasi-harmonic model with local phonon density of states (LPDOS) to compute the thermodynamic and mechanical properties of silicon nanostructures at finite temperature. In contrast to an earlier approach (Tang and Aluru 2006 Phys. Rev. B 74 235441), where a quasi-harmonic model with LPDOS computed by a Green's function technique (QHMG) was developed considering many layers of atoms, the semi-local approach considers only two layers of atoms to compute the LPDOS. We show that the semi-local approach combines the accuracy of the QHMG approach and the computational efficiency of the local quasi-harmonic model. We present results for several silicon nanostructures to address the accuracy and efficiency of the semi-local approach

  18. Semi-Arid Plantation by Anatolian Black Pine and Its Effects on Soil Erosion and Soil Properties

    Directory of Open Access Journals (Sweden)

    Sezgin Hacisalihoglu

    2018-04-01

    Full Text Available In this study, the effects of Anatolian Black pine [(Pinus nigra Arn. subsp. pallasiana (Lamb. Holmboe] plantation on hydro-physical soil properties and soil loss were investigated. This study was carried out on the afforestation field of Anatolian Black Pine in the Gölbaşı district of Ankara province, which is included in the arid and semi-arid regions. Totally 48 soil sample in two soil depth level (0-20cm, 20-50cm were collected from forest (36 soil sample and barren (control area (12 soil sample. Hydro-physically important soil properties were analysed [Sand (%, Silt (%, Clay (%, Organic Matter (%, pH, Field Capacity (%, Wilting Point (%, Saturation (%, Available Water Holding Capacity (cm/cm Saturated Hydraulic Conductivity (cm/hr, Bulk Density (gr/cm3]. And soil loss in a unit area by using ABAG (Allgemeine Boden Abtrags Gleichung model was estimated. Soil properties and soil loss amount relations among the land use group were determined. Topsoil (0-20cm and subsoil (20-50cm properties except subsoil organic matter were significantly affected by land use group. Finally, Significant changes were found for annual soil loss amounts in a unit area. Avarage annual soil loss in planted area was found approximately 5.5 times less than barren area at 0-50 cm soil depth. Vegetation factor (C which is one of the most important components of the soil loss equation, has been significantly affected by afforestation in a short period of 40 years and thus it was a variable to reduce to soil loss.

  19. Interpreting equilibrium-conductivity and conductivity-relaxation measurements to establish thermodynamic and transport properties for multiple charged defect conducting ceramics.

    Science.gov (United States)

    Zhu, Huayang; Ricote, Sandrine; Coors, W Grover; Kee, Robert J

    2015-01-01

    A model-based interpretation of measured equilibrium conductivity and conductivity relaxation is developed to establish thermodynamic, transport, and kinetics parameters for multiple charged defect conducting (MCDC) ceramic materials. The present study focuses on 10% yttrium-doped barium zirconate (BZY10). In principle, using the Nernst-Einstein relationship, equilibrium conductivity measurements are sufficient to establish thermodynamic and transport properties. However, in practice it is difficult to establish unique sets of properties using equilibrium conductivity alone. Combining equilibrium and conductivity-relaxation measurements serves to significantly improve the quantitative fidelity of the derived material properties. The models are developed using a Nernst-Planck-Poisson (NPP) formulation, which enables the quantitative representation of conductivity relaxations caused by very large changes in oxygen partial pressure.

  20. Determination of Transport Properties From Flowing Fluid Temperature Logging In Unsaturated Fractured Rocks: Theory And Semi-Analytical Solution

    International Nuclear Information System (INIS)

    Mukhopadhyay, Sumit; Tsang, Yvonne W.

    2008-01-01

    Flowing fluid temperature logging (FFTL) has been recently proposed as a method to locate flowing fractures. We argue that FFTL, backed up by data from high-precision distributed temperature sensors, can be a useful tool in locating flowing fractures and in estimating the transport properties of unsaturated fractured rocks. We have developed the theoretical background needed to analyze data from FFTL. In this paper, we present a simplified conceptualization of FFTL in unsaturated fractured rock, and develop a semianalytical solution for spatial and temporal variations of pressure and temperature inside a borehole in response to an applied perturbation (pumping of air from the borehole). We compare the semi-analytical solution with predictions from the TOUGH2 numerical simulator. Based on the semi-analytical solution, we propose a method to estimate the permeability of the fracture continuum surrounding the borehole. Using this proposed method, we estimated the effective fracture continuum permeability of the unsaturated rock hosting the Drift Scale Test (DST) at Yucca Mountain, Nevada. Our estimate compares well with previous independent estimates for fracture permeability of the DST host rock. The conceptual model of FFTL presented in this paper is based on the assumptions of single-phase flow, convection-only heat transfer, and negligible change in system state of the rock formation. In a sequel paper (Mukhopadhyay et al., 2008), we extend the conceptual model to evaluate some of these assumptions. We also perform inverse modeling of FFTL data to estimate, in addition to permeability, other transport parameters (such as porosity and thermal conductivity) of unsaturated fractured rocks

  1. An environment-dependent semi-empirical tight binding model suitable for electron transport in bulk metals, metal alloys, metallic interfaces, and metallic nanostructures. II. Application—Effect of quantum confinement and homogeneous strain on Cu conductance

    Science.gov (United States)

    Hegde, Ganesh; Povolotskyi, Michael; Kubis, Tillmann; Charles, James; Klimeck, Gerhard

    2014-03-01

    The Semi-Empirical tight binding model developed in Part I Hegde et al. [J. Appl. Phys. 115, 123703 (2014)] is applied to metal transport problems of current relevance in Part II. A systematic study of the effect of quantum confinement, transport orientation, and homogeneous strain on electronic transport properties of Cu is carried out. It is found that quantum confinement from bulk to nanowire boundary conditions leads to significant anisotropy in conductance of Cu along different transport orientations. Compressive homogeneous strain is found to reduce resistivity by increasing the density of conducting modes in Cu. The [110] transport orientation in Cu nanowires is found to be the most favorable for mitigating conductivity degradation since it shows least reduction in conductance with confinement and responds most favorably to compressive strain.

  2. An environment-dependent semi-empirical tight binding model suitable for electron transport in bulk metals, metal alloys, metallic interfaces, and metallic nanostructures. II. Application—Effect of quantum confinement and homogeneous strain on Cu conductance

    International Nuclear Information System (INIS)

    Hegde, Ganesh; Povolotskyi, Michael; Kubis, Tillmann; Charles, James; Klimeck, Gerhard

    2014-01-01

    The Semi-Empirical tight binding model developed in Part I Hegde et al. [J. Appl. Phys. 115, 123703 (2014)] is applied to metal transport problems of current relevance in Part II. A systematic study of the effect of quantum confinement, transport orientation, and homogeneous strain on electronic transport properties of Cu is carried out. It is found that quantum confinement from bulk to nanowire boundary conditions leads to significant anisotropy in conductance of Cu along different transport orientations. Compressive homogeneous strain is found to reduce resistivity by increasing the density of conducting modes in Cu. The [110] transport orientation in Cu nanowires is found to be the most favorable for mitigating conductivity degradation since it shows least reduction in conductance with confinement and responds most favorably to compressive strain

  3. An environment-dependent semi-empirical tight binding model suitable for electron transport in bulk metals, metal alloys, metallic interfaces, and metallic nanostructures. II. Application—Effect of quantum confinement and homogeneous strain on Cu conductance

    Energy Technology Data Exchange (ETDEWEB)

    Hegde, Ganesh, E-mail: ghegde@purdue.edu; Povolotskyi, Michael; Kubis, Tillmann; Charles, James; Klimeck, Gerhard, E-mail: gekco@purdue.edu [Network for Computational Nanotechnology (NCN), Department of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

    2014-03-28

    The Semi-Empirical tight binding model developed in Part I Hegde et al. [J. Appl. Phys. 115, 123703 (2014)] is applied to metal transport problems of current relevance in Part II. A systematic study of the effect of quantum confinement, transport orientation, and homogeneous strain on electronic transport properties of Cu is carried out. It is found that quantum confinement from bulk to nanowire boundary conditions leads to significant anisotropy in conductance of Cu along different transport orientations. Compressive homogeneous strain is found to reduce resistivity by increasing the density of conducting modes in Cu. The [110] transport orientation in Cu nanowires is found to be the most favorable for mitigating conductivity degradation since it shows least reduction in conductance with confinement and responds most favorably to compressive strain.

  4. Pore scale modelling of electrical and hydraulic properties of a semi-consolidated sandstone under unsaturated conditions

    Science.gov (United States)

    Cassiani, G.; dalla, E.; Brovelli, A.; Pitea, D.; Binley, A. M.

    2003-04-01

    The development of reliable constitutive laws to translate geophysical properties into hydrological ones is the fundamental step for successful applications of hydrogeophysical techniques. Many such laws have been proposed and applied, particularly with regard to two types of relationships: (a) between moisture content and dielectric properties, and (b) between electrical resistivity, rock structure and water saturation. The classical Archie's law belongs to this latter category. Archie's relationship has been widely used, starting from borehole logs applications, to translate geoelectrical measurements into estimates of saturation. However, in spite of its popularity, it remains an empirical relationship, the parameters of which must be calibrated case by case, e.g. on laboratory data. Pore-scale models have been recently recognized and used as powerful tools to investigate the constitutive relations of multiphase soils from a pore-scale point of view, because they bridge the microscopic and macroscopic scales. In this project, we develop and validate a three-dimensional pore-scale method to compute electrical properties of unsaturated and saturated porous media. First we simulate a random packing of spheres [1] that obeys the grain-size distribution and porosity of an experimental porous medium system; then we simulate primary drainage with a morphological approach [2]; finally, for each state of saturation during the drainage process, we solve the electrical conduction equation within the grain structure with a new numerical model and compute the apparent electrical resistivity of the porous medium. We apply the new method to a semi-consolidated Permo-Triassic Sandstone from the UK (Sherwood Sandstone) for which both pressure-saturation (Van Genuchten) and Archie's law parameters have been measured on laboratory samples. A comparison between simulated and measured relationships has been performed.

  5. Low-temperature VRH conduction through complex materials in the presence of a temperature-dependent voltage threshold: A semi-classical percolative approach

    International Nuclear Information System (INIS)

    Sen, A.K.; Bhattacharya, S.

    2006-12-01

    In this paper, we study the variation of low temperature (T) dc conductance, G(T), of a semi-classical percolative Random Resistor cum Tunneling-bond Network (RRTN), in the presence of a linearly temperature-dependent microscopic voltage threshold, υ g (T). This model (proposed by our group in the early 90's) considers a phenomenological semi-classical tunneling (or, hopping through a barrier) process. Just as in our previous constant-υ g case, we find in the present study also that the variable range hopping (VRH) exponent γ varies continuously with the ohmic concentration p in a non-monotonic fashion. In addition, we observe a new shoulder-like behaviour of G(T) in the intermediate temperature range, below the conductance maximum. (author)

  6. Studies on conductivity and dielectric properties of polyaniline–zinc ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. In the present paper, we report electrical conductivity and dielectric studies on the composites of conducting polyaniline (PANI) with crystalline semiconducting ZnS powder, wherein PANI has been taken as inclusion and ZnS crystallites as the host matrix. From the studies, it has been observed that the value of.

  7. Soil hydraulic properties near saturation, an improved conductivity model

    DEFF Research Database (Denmark)

    Børgesen, Christen Duus; Jacobsen, Ole Hørbye; Hansen, Søren

    2006-01-01

    of commonly used hydraulic conductivity models and give suggestions for improved models. Water retention and near saturated and saturated hydraulic conductivity were measured for a variety of 81 top and subsoils. The hydraulic conductivity models by van Genuchten [van Genuchten, 1980. A closed-form equation...... for predicting the hydraulic conductivity of unsaturated soils. Soil Sci. Soc. Am. J. 44, 892–898.] (vGM) and Brooks and Corey, modified by Jarvis [Jarvis, 1991. MACRO—A Model of Water Movement and Solute Transport in Macroporous Soils. Swedish University of Agricultural Sciences. Department of Soil Sciences....... Optimising a matching factor (k0) improved the fit considerably whereas optimising the l-parameter in the vGM model improved the fit only slightly. The vGM was improved with an empirical scaling function to account for the rapid increase in conductivity near saturation. Using the improved models...

  8. Temperature-dependent ionic conductivity and transport properties ...

    Indian Academy of Sciences (India)

    Administrator

    A conductivity cell containing two stainless-steel block- ing electrodes ... tions by matching the device impedance to the cable .... reveals that the presence of large negative value in the ... site exhibits VTF phenomenological relationship. 1/2 dc.

  9. Nanoionics phenomenon in proton-conducting oxide: Effect of dispersion of nanosize platinum particles on electrical conduction properties

    Directory of Open Access Journals (Sweden)

    Hiroshige Matsumoto et al

    2007-01-01

    Full Text Available High-temperature proton conductors are oxides in which low-valence cations are doped as electron acceptors; the incorporation of water molecules into the oxides results in the formation of protonic defects that act as charge carriers. Since the protons thus formed are in equilibrium with other electronic defects, electrons and holes, the oxides possibly have different proton-conduction properties at and near boundaries when they are in contact with another phase. In this paper, we present our recent experimental observation of a marked change in the electrical properties of a proton conductor upon the dispersal of fine platinum particles in the oxide. First, the material shows extremely low electrical conductivity in comparison with the original proton-conducting perovskite. Second, there was a threshold amount of platinum at which such a drop in conductivity occurred. A percolation model is employed to explain these experimental results; the fine platinum particles dispersed in the proton-conducting oxide wears highly resistive skin that is formed due to shifts in defect equilibriums, which prevents ionic/electronic conduction. The experiments suggest that the ion-conducting properties of oxides can be varied by introducing interfaces at a certain density; nanoionics is a key to yielding enhanced and/or controlled ionic conduction in solids.

  10. Optimization of electrical conduction and passivity properties of stainless steels used for PEM fuel cell bipolar plates

    International Nuclear Information System (INIS)

    Andre, J.

    2007-10-01

    Among the new technologies for energy for sustainable development, PEMFC (proton exchange membrane fuel cells) offer seducing aspects. However, in order to make this technology fit large scale application requirements, it has to comply with stringent cost, performance, and durability criteria. In such a frame, the goal of this work was to optimize electrical conduction properties and passivity of stainless steels for the conception of PEMFC bipolar plates, used instead of graphite, the reference material. This work presents the possible ways of performance loss when using stainless steels and some methods to solve this problem. Passive film properties were studied, as well as their modifications by low cost industrial surface treatments, without deposition. Ex situ characterizations of corrosion resistance and electrical conduction were performed. Electrochemical impedance spectroscopy, water analysis, surface analysis by microscopy and photoelectron spectroscopy allowed to study the impact of ageing on two alloys in different states, and several conditions representative of an exposure to PEMFC media. Correlations between semi-conductivity properties, composition, and structure of passive layers were considered, but not leading to clear identification of all parameters responsible for electrical conduction and passivity. The plate industrial state is not convenient for direct use in fuel cell to comply with durability and performance requirements. A surface modification studied improves widely electrical conduction at initial state. The performance is degraded with ageing, but maintaining a level higher than the initial industrial state. This treatment increases also corrosion resistance, particularly on the anode side. (author)

  11. 39 CFR 232.1 - Conduct on postal property.

    Science.gov (United States)

    2010-07-01

    ... promotion of social welfare but do not participate or intervene in any political campaign on behalf of any candidate or political party for any public office. (ii) Absolutely no partisan or political literature may... that will protect Postal Service property. (3) Postal Inspectors, Office of Inspector General Criminal...

  12. Deriving seasonal dynamics in ecosystem properties of semi-arid savanna grasslands from in situ-based hyperspectral reflectance

    DEFF Research Database (Denmark)

    Tagesson, Håkan Torbern; Fensholt, Rasmus; Huber, S.

    2015-01-01

    strongly affected by solar zenith angles and sensor viewing geometry, as were many combinations of visible wavelengths. This study provides analyses based upon novel multi-angular hyperspectral data for validation of Earth-observation-based properties of semi-arid ecosystems, as well as insights...... between normalised difference spectral indices (NDSIs) and the measured ecosystem properties. Finally, the effects of variable sun sensor viewing geometry on different NDSI wavelength combinations were analysed. The wavelengths with the strongest correlation to seasonal dynamics in ecosystem properties...

  13. Tunable Surface Properties of a Conductive PEDOT/EVAL blend

    DEFF Research Database (Denmark)

    Pizzi, Elisa; Martinelli, Andrea; D'Ilario, Lucio

    Conductive polymers have been studied extensively during recent years. Especially,poly(3,4-ethylenedioxythiophene) (PEDOT) have found many application areas and arebroadly considered one of the most promising conductive polymers. In order to broadenthe application field of PEDOT we have developed...... an azide functional poly(3,4-ethylenedioxythiophene) (PEDOT-N3)1. The azide functional conductive polymer canbe postpolymerization functionalized to introduce a large range of molecules onto theconductive backbone through click chemistry2.Here we present a study of the incorporation of poly......(ethylene-co-vinyl alcohol) (EVAL)into a copolymer of EDOT and EDOT-N3 (poly(EDOT-co-EDOT-N3)). Poly(ethyleneco-vinyl alcohol) (EVAL) is known to swell in polar solvents, which was exploited inthis study to permit a good blending of the two polymers. Since both polymers haveresidual functional groups the polymer blend...

  14. Dielectric and conductivity properties of composite polyaniline/polyurethane network

    Science.gov (United States)

    Liang, C.; Gest, J.; Leroy, G.; Carru, J.-C.

    2013-09-01

    In this work, we present the dielectric characterization of polyaniline/polyurethane composite. The samples consisting of 0.5%, 1%, and 5% of polyaniline were deposited on glass fiber, and the measurements were performed in a frequency range of 20 Hz to 20 GHz. The results showed a dielectric relaxation strongly dependent on the concentration of polyaniline. This phenomenon is explained by a theoretical model. In this model, we assume that the alternative conductivity of the polymer network systems is due to conducting clusters whose lengths followed a Gaussian distribution. Depending on their size and the frequency of the excitation signal, the clusters showed a resistive or capacitive effect.

  15. Synthesis, ionic conductivity, and thermal properties of proton conducting polymer electrolyte for high temperature fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Takahito; Hamaguchi, Yohei; Uno, Takahiro; Kubo, Masataka [Department of Chemistry for Materials, Faculty of Engineering, Mie University, 1577 Kurima Machiya-cho, Tsu, Mie 514-8507 (Japan); Aihara, Yuichi; Sonai, Atsuo [Samsung Yokohama Research Institute, 2-7 Sugasawa-cho, Tsurumi-ku, Yokohama 230-0027 (Japan)

    2006-01-16

    Hyperbranched polymer (poly-1a) with sulfonic acid groups at the end of chains was successfully synthesized. Interpenetration reaction of poly-1a with a hyperbranched polymer with acryloyl groups at the end of chains (poly-1b) as a cross-linker afforded a tough electrolyte membrane. The poly-1a and the resulting electrolyte membrane showed the ionic conductivities of 7x10{sup -4} and 8x10{sup -5} S/cm, respectively, at 150C under dry condition. The ionic conductivities of the poly-1a and the electrolyte membrane exhibited the VTF type temperature dependence. And also, both poly-1a and the resulting electrolyte membrane were thermally stable up to 200C. (author)

  16. Effect of Ultrasonic Vibration on Mechanical Properties of 3D Printing Non-Crystalline and Semi-Crystalline Polymers.

    Science.gov (United States)

    Li, Guiwei; Zhao, Ji; Wu, Wenzheng; Jiang, Jili; Wang, Bofan; Jiang, Hao; Fuh, Jerry Ying Hsi

    2018-05-17

    Fused deposition modeling 3D printing has become the most widely used additive manufacturing technology because of its low manufacturing cost and simple manufacturing process. However, the mechanical properties of the 3D printing parts are not satisfactory. Certain pressure and ultrasonic vibration were applied to 3D printed samples to study the effect on the mechanical properties of 3D printed non-crystalline and semi-crystalline polymers. The tensile strength of the semi-crystalline polymer polylactic acid was increased by 22.83% and the bending strength was increased by 49.05%, which were almost twice the percentage increase in the tensile strength and five times the percentage increase in the bending strength of the non-crystalline polymer acrylonitrile butadiene styrene with ultrasonic strengthening. The dynamic mechanical properties of the non-crystalline and semi-crystalline polymers were both improved after ultrasonic enhancement. Employing ultrasonic energy can significantly improve the mechanical properties of samples without modifying the 3D printed material or adjusting the forming process parameters.

  17. Voltage-Induced Nonlinear Conduction Properties of Epoxy Resin/Micron-Silver Particles Composites

    Science.gov (United States)

    Qu, Zhaoming; Lu, Pin; Yuan, Yang; Wang, Qingguo

    2018-01-01

    The nonlinear conduction properties of epoxy resin (ER)/micron-silver particles (MP) composites were investigated. Under sufficient high intensity applied constant voltage, the obvious nonlinear conduction properties of the samples with volume fraction 25% were found. With increments in the voltage, the conductive switching effect was observed. The nonlinear conduction mechanism of the ER/MP composites under high applied voltages could be attributed to the electrical current conducted via discrete paths of conductive particles induced by the electric field. The test results show that the ER/MP composites with nonlinear conduction properties are of great potential application in electromagnetic protection of electron devices and systems.

  18. AC Conductivity and Dielectric Properties of Borotellurite Glass

    Science.gov (United States)

    Taha, T. A.; Azab, A. A.

    2016-10-01

    Borotellurite glasses with formula 60B2O3-10ZnO-(30 - x)NaF- xTeO2 ( x = 0 mol.%, 5 mol.%, 10 mol.%, and 15 mol.%) have been synthesized by thermal melting. X-ray diffraction (XRD) analysis confirmed that the glasses were amorphous. The glass density ( ρ) was determined by the Archimedes method at room temperature. The density ( ρ) and molar volume ( V m) were found to increase with increasing TeO2 content. The direct-current (DC) conductivity was measured in the temperature range from 473 K to 623 K, in which the electrical activation energy of ionic conduction increased from 0.27 eV to 0.48 eV with increasing TeO2 content from 0 mol.% to 15 mol.%. The dielectric parameters and alternating-current (AC) conductivity ( σ ac) were investigated in the frequency range from 1 kHz to 1 MHz and temperature range from 300 K to 633 K. The AC conductivity and dielectric constant decreased with increasing TeO2 content from 0 mol.% to 15 mol.%.

  19. Effect of conduction band nonparabolicity on the optical properties in ...

    Indian Academy of Sciences (India)

    the bulk conduction band edge, the correction due to nonparabolicity can be important. [9,10]. In a narrow QW under a strong magnetic field, the optical absorption coefficients calculated with the nonparabolicity correction shows remarkable deviation from results obtained using parabolic energy approximation [11].

  20. Silicate bonding properties: Investigation through thermal conductivity measurements

    Energy Technology Data Exchange (ETDEWEB)

    Lorenzini, M; Cesarini, E; Cagnoli, G; Campagna, E; Losurdo, G; Martelli, F; Piergiovanni, F; Vetrano, F [INFN, Istituto Nazionale di Fisica Nucleare, Sez. di Firenze, via G. Sansone 1, 50019 Sesto Fiorentino (Italy); Haughian, K; Hough, J; Martin, I; Reid, S; Rowan, S; Veggel, A A van, E-mail: lorenzini@fi.infn.i [SUPA, University of Glasgow, Department of Physics and Astronomy, Kelvin Building G12 8QQ Glasgow, Scotland (United Kingdom)

    2010-05-01

    A direct approach to reduce the thermal noise contribution to the sensitivity limit of a GW interferometric detector is the cryogenic cooling of the mirrors and mirrors suspensions. Future generations of detectors are foreseen to implement this solution. Silicon has been proposed as a candidate material, thanks to its very low intrinsic loss angle at low temperatures and due to its very high thermal conductivity, allowing the heat deposited in the mirrors by high power lasers to be efficiently extracted. To accomplish such a scheme, both mirror masses and suspension elements must be made of silicon, then bonded together forming a quasi-monolithic stage. Elements can be assembled using hydroxide-catalysis silicate bonding, as for silica monolithic joints. The effect of Si to Si bonding on suspension thermal conductance has therefore to be experimentally studied. A measurement of the effect of silicate bonding on thermal conductance carried out on 1 inch thick silicon bonded samples, from room temperature down to 77 K, is reported. In the explored temperature range, the silicate bonding does not seem to affect in a relevant way the sample conductance.

  1. Mobility of indaziflam influenced by soil properties in a semi-arid area.

    Directory of Open Access Journals (Sweden)

    Amir M González-Delgado

    Full Text Available Indaziflam, a broad-spectrum, pre-emergence herbicide was the focus of a field investigation conducted after the identification of sporadic injury symptoms on the pecan trees a few months after the application. The study was conducted in two pecan orchards located in southern New Mexico, USA, and southeastern Arizona, USA. The objectives of this study were to evaluate the occurrence and distribution of indaziflam in the soil profile of areas where pecan trees were injured (impacted and areas where no injury symptoms were observed (unimpacted, and to determine the relationship between indaziflam concentrations and soil properties in those locations. Soil samples were collected, one year after applications, from six depth representing 0-7, 7-15, 15-30, 30-60, 60-90 and 90-120 cm depth to determine the concentration of indaziflam in impacted and unimpacted areas of the two orchards. Soil samples were analyzed to determine texture, bulk density, organic matter content, cation exchange capacity, pH, nitrate, chloride and calcium concentrations. The detection frequency of indaziflam was higher in Arizona than in New Mexico, likely due to the differences between the tillage practices and sand contents of the orchards. No significant correlations were observed between indaziflam and soil properties, however indaziflam was mostly detected in areas where pecan trees were unimpacted probably as result of greater organic matter content and soil porosity. More research is needed to understand the causes of injury to pecan trees by indaziflam application.

  2. 41 CFR 102-75.1260 - Does GSA conduct Federal screening on every property reported as excess real property?

    Science.gov (United States)

    2010-07-01

    ... of hazardous substances at the Government-owned facility; (e) The property is an easement; (f) The... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Does GSA conduct Federal... Contracts and Property Management Federal Property Management Regulations System (Continued) FEDERAL...

  3. Structural and electrical properties of conducting diamond nanowires.

    Science.gov (United States)

    Sankaran, Kamatchi Jothiramalingam; Lin, Yen-Fu; Jian, Wen-Bin; Chen, Huang-Chin; Panda, Kalpataru; Sundaravel, Balakrishnan; Dong, Chung-Li; Tai, Nyan-Hwa; Lin, I-Nan

    2013-02-01

    Conducting diamond nanowires (DNWs) films have been synthesized by N₂-based microwave plasma enhanced chemical vapor deposition. The incorporation of nitrogen into DNWs films is examined by C 1s X-ray photoemission spectroscopy and morphology of DNWs is discerned using field-emission scanning electron microscopy and transmission electron microscopy (TEM). The electron diffraction pattern, the visible-Raman spectroscopy, and the near-edge X-ray absorption fine structure spectroscopy display the coexistence of sp³ diamond and sp² graphitic phases in DNWs films. In addition, the microstructure investigation, carried out by high-resolution TEM with Fourier transformed pattern, indicates diamond grains and graphitic grain boundaries on surface of DNWs. The same result is confirmed by scanning tunneling microscopy and scanning tunneling spectroscopy (STS). Furthermore, the STS spectra of current-voltage curves discover a high tunneling current at the position near the graphitic grain boundaries. These highly conducting regimes of grain boundaries form effective electron paths and its transport mechanism is explained by the three-dimensional (3D) Mott's variable range hopping in a wide temperature from 300 to 20 K. Interestingly, this specific feature of high conducting grain boundaries of DNWs demonstrates a high efficiency in field emission and pave a way to the next generation of high-definition flat panel displays or plasma devices.

  4. Semi-Degradable Poly(β-amino ester) Networks with Temporally-Controlled Enhancement of Mechanical Properties

    Science.gov (United States)

    Safranski, David L.; Weiss, Daiana; Clark, J. Brian; Taylor, W.R.; Gall, Ken

    2014-01-01

    Biodegradable polymers are clinically used in numerous biomedical applications, and classically show a loss in mechanical properties within weeks of implantation. This work demonstrates a new class of semi-degradable polymers that show an increase in mechanical properties through degradation via a controlled shift in a thermal transition. Semi-degradable polymer networks, poly(β-amino ester)-co-methyl methacrylate, were formed from a low glass transition temperature crosslinker, poly(β-amino ester), and high glass transition temperature monomer, methyl methacrylate, which degraded in a manner dependent upon the crosslinker chemical structure. In vitro and in vivo degradation revealed changes in mechanical behavior due to the degradation of the crosslinker from the polymer network. This novel polymer system demonstrates a strategy to temporally control the mechanical behavior of polymers and to enhance the initial performance of smart biomedical devices. PMID:24769113

  5. The Spectroscopic and Conductive Properties of Ru(II Complexes with Potential Anticancer Properties

    Directory of Open Access Journals (Sweden)

    Adebayo A. Adeniyi

    2014-01-01

    Full Text Available Different density functional methods (DFT have been used to optimize and study the chemistry of five potential anticancer complexes in terms of their electronic, conductive, and spectroscopic properties. Many of the computed properties in addition to the IR and QTAIM analysis of the NMR are dipole moment vector (μi, linear polarizability tensor (αij, first hyperpolarizability tensors (βijk, polarizability exaltation index (Γ, and chemical hardness (η of the complexes. Stable low energy geometries are obtained using basis set with effective core potential (ECP approximation but, in the computation of atomic or molecular properties, the metal Ru atom is better treated with higher all electron basis set like DGDZVP. The spectroscopic features like the IR of the metal-ligand bonds and the isotropic NMR shielding tensor of the coordinated atoms are significantly influenced by the chemical environment of the participating atoms. The carboxylic and pyrazole units are found to significantly enhance the polarizabilities and hyperpolarizabilities of the complexes while the chloride only improves the polarity of the complexes. Fermi contacts (FC have the highest effect followed by the PSO among all the four Ramsey terms which defined the total spin-spin coupling constant J (HZ of these complexes.

  6. Modeling the overall heat conductive and convective properties of open-cell graphite foam

    International Nuclear Information System (INIS)

    Tee, C C; Yu, N; Li, H

    2008-01-01

    This work develops analytic models on the overall thermal conductivity, pressure drop and overall convective heat transfer coefficient of graphite foam. The models study the relationship between the overall heat conductive and convective properties, and foam microstructure, temperature, foam surface friction characteristics and cooling fluid properties. The predicted thermal conductivity, convective heat transfer coefficient and pressure drop agree well with experimental data

  7. Steady-state properties of Josephson junctions with direct conductivity

    International Nuclear Information System (INIS)

    Zubkov, A.A.; Kupriyanov, M.Y.; Semenov, V.K.

    1981-01-01

    A new criterion for determining the kinetic inductance of Josephson junctions is introduced. The effects of temperature T, the critical temperatures of the superconducting electrodes T/sub c/1 and T/sub c/2, and the weak-link length on the kinetic inductance of ''dirty'' junctions with direct conductivity are analyzed within the framework of the Usadel equations. Numerical calculations show that both a large characteristic voltage and a nearly harmonic dependence of the current on the phase difference of the superconducting-electrode wave functions cannot be obtained by varying the junction parameters

  8. Heat pipes with variable thermal conductance property for space applications

    Energy Technology Data Exchange (ETDEWEB)

    Kravets, V.; Alekseik, Ye.; Alekseik, O.; Khairnasov, S. [National Technical University of Ukraine, Kyiv (Ukraine); Baturkin, V.; Ho, T. [Explorationssysteme RY-ES, Bremen (Germany); Celotti, L. [Active Space Technologies GmbH, Berlin (Germany)

    2017-06-15

    The activities presented in this paper demonstrate a new approach to provide passive thermal control using heat pipes, as demonstrated on the electronic unit of DLR’s MASCOT lander, which embarked on the NEA sample return mission Hayabusa 2 (JAXA). The focus is on the development and testing of heat pipes with variable thermal conductance in a predetermined temperature range. These heat pipes act as thermal switches. Unlike standard gasloaded heat pipes and thermal-diode heat pipes construction of presented heat pipes does not include any additional elements. Copper heat pipes with metal fibrous wicks were chosen as baseline design. We obtained positive results by choosing the heat carrier and structural parameters of the wick (i.e., pore diameter, porosity, and permeability). The increase in the thermal conductivity of the heat pipes from 0.04 W/K to 2.1 W/K was observed in the temperature range between −20 °C and +55 °C. Moreover, the heat pipes transferred the predetermined power of not less than 10 W within the same temperature range. The heat pipes have been in flight since December 2014, and the supporting telemetry data were obtained in September 2015. The data showed the nominal operation of the thermal control system.

  9. Scaling properties of conduction velocity in heterogeneous excitable media

    Science.gov (United States)

    Shajahan, T. K.; Borek, Bartłomiej; Shrier, Alvin; Glass, Leon

    2011-10-01

    Waves of excitation through excitable media, such as cardiac tissue, can propagate as plane waves or break up to form reentrant spiral waves. In diseased hearts reentrant waves can be associated with fatal cardiac arrhythmias. In this paper we investigate the conditions that lead to wave break, reentry, and propagation failure in mathematical models of heterogeneous excitable media. Two types of heterogeneities are considered: sinks are regions in space in which the voltage is fixed at its rest value, and breaks are nonconducting regions with no-flux boundary conditions. We find that randomly distributed heterogeneities in the medium have a decremental effect on the velocity, and above a critical density of such heterogeneities the conduction fails. Using numerical and analytical methods we derive the general relationship among the conduction velocity, density of heterogeneities, diffusion coefficient, and the rise time of the excitation in both two and three dimensions. This work helps us understand the factors leading to reduced propagation velocity and the formation of spiral waves in heterogeneous excitable media.

  10. Synthesis of polymer nanostructures with conductance switching properties

    Science.gov (United States)

    Su, Kai; Nuraje, Nurxat; Zhang, Lingzhi; Matsui, Hiroshi; Yang, Nan Loh

    2015-03-03

    The present invention is directed to crystalline organic polymer nanoparticles comprising a conductive organic polymer; wherein the crystalline organic polymer nanoparticles have a size of from 10 nm to 200 nm and exhibits two current-voltage states: (1) a high resistance current-voltage state, and (2) a low resistance current-voltage state, wherein when a first positive threshold voltage (V.sub.th1) or higher positive voltage, or a second negative threshold voltage (V.sub.th2) or higher negative voltage is applied to the nanoparticle, the nanoparticle exhibits the low-resistance current-voltage state, and when a voltage less positive than the first positive threshold voltage or a voltage less negative than the second negative threshold voltage is applied to the nanoparticle, the nanoparticle exhibits the high-resistance current-voltage state. The present invention is also directed methods of manufacturing the nanoparticles using novel interfacial oxidative polymerization techniques.

  11. Synthesis, sintering properties and thermal conductivity of uranium carbonitrides

    International Nuclear Information System (INIS)

    Wolters, R.A.M.

    1978-01-01

    An introduction to the applications and chemistry of uranium carbonitrides is given including the potential use as a nuclear fuel. The powder synthesis of UC, UN and mixtures of UC and UN by a cyclic process is described. The correlation between the composition ratio UN/(UC+UN) in the final product and the parameters of the process is only determined qualitatively. Batch synthesis of a powder does not lead to an increase of the content of metallic impurities and oxygen. The impurity level is determined by that of the starting uranium metal and the thermal conductivity of the sintered compacts of uranium carbonitrides are determined via the measurement of the thermal diffusivity at 1100-1700 K. (Auth.)

  12. Structure and properties of semi-interpenetrating network hydrogel based on starch.

    Science.gov (United States)

    Zhu, Baodong; Ma, Dongzhuo; Wang, Jian; Zhang, Shuang

    2015-11-20

    Starch-g-P(acrylic acid-co-acrylamide)/PVA semi-interpenetrating network (semi-IPN) hydrogels were prepared by aqueous solution polymerization method. Starch grafting copolymerization reaction, semi-IPN structure and crystal morphology were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The PVA in the form of partial crystallization distributing in the gel matrix uniformly were observed by Field emission scanning electron microscope (FESEM). The space network structure, finer microstructure and pore size in the interior of hydrogel were presented by biomicroscope. The results demonstrated that absorption ratio of water and salt generated different degree changes with the effect of PVA. In addition, the mechanical strength of hydrogel was improved. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Impact of Industrial Grade Modified PVA to Vinyl Acetate Semi-continuous Emulsion Polymerization and Properties of Final Product

    Directory of Open Access Journals (Sweden)

    Mindaugas DUBININKAS

    2013-03-01

    Full Text Available Successful vinyl acetate radical emulsion polymerization in water with different type of industrial grade poly(vinyl alcohol were produced by semi continuous way. The poly(vinyl alcohol type has crucial impact on dispersion rheological as well on films and bonding strength properties. It should be stated that the films containing modified poly (vinyl alcohol has better water resistance and mechanical properties. Poly(vinyl alcohol with higher ethylene moieties content and high hydrolization degree determines extremely low viscosity of final dispersion.DOI: http://dx.doi.org/10.5755/j01.ms.19.1.3823

  14. Volatile and non-volatile/semi-volatile compounds and in vitro bioactive properties of Chilean Ulmo (Eucryphia cordifolia Cav.) honey.

    Science.gov (United States)

    Acevedo, Francisca; Torres, Paulina; Oomah, B Dave; de Alencar, Severino Matias; Massarioli, Adna Prado; Martín-Venegas, Raquel; Albarral-Ávila, Vicenta; Burgos-Díaz, César; Ferrer, Ruth; Rubilar, Mónica

    2017-04-01

    Ulmo honey originating from Eucryphia cordifolia tree, known locally in the Araucania region as the Ulmo tree is a natural product with valuable nutritional and medicinal qualities. It has been used in the Mapuche culture to treat infections. This study aimed to identify the volatile and non-volatile/semi-volatile compounds of Ulmo honey and elucidate its in vitro biological properties by evaluating its antioxidant, antibacterial, antiproliferative and hemolytic properties and cytotoxicity in Caco-2 cells. Headspace volatiles of Ulmo honey were isolated by solid-phase microextraction (SPME); non-volatiles/semi-volatiles were obtained by removing all saccharides with acidified water and the compounds were identified by GC/MS analysis. Ulmo honey volatiles consisted of 50 compounds predominated by 20 flavor components. Two of the volatile compounds, lyrame and anethol have never been reported before as honey compounds. The non-volatile/semi-volatile components of Ulmo honey comprised 27 compounds including 13 benzene derivatives accounting 75% of the total peak area. Ulmo honey exhibited weak antioxidant activity but strong antibacterial activity particularly against gram-negative bacteria and methicillin-resistant Staphylococcus aureus (MRSA), the main strain involved in wounds and skin infections. At concentrations >0.5%, Ulmo honey reduced Caco-2 cell viability, released lactate dehydrogenase (LDH) and increased reactive oxygen species (ROS) production in a dose dependent manner in the presence of foetal bovine serum (FBS). The wide array of volatile and non-volatile/semi-volatile constituents of Ulmo honey rich in benzene derivatives may partly account for its strong antibacterial and antiproliferative properties important for its therapeutic use. Our results indicate that Ulmo honey can potentially inhibit cancer growth at least partly by modulating oxidative stress. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. A thermodynamic analysis of non-equilibrium heat conduction in a semi-infinite medium subjected to a step change in temperature

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, A.K.; Hussain, T.A.; Shahad, Haroun A.K. [Babylon Univ., Dept. of Mechanical Engineering, Babylon (Iraq)

    2003-05-01

    The problem of non-equilibrium heat conduction in a semi-infinite medium subjected to a step change in temperature is analyzed thermodynamically using the extended irreversible thermodynamic approach. The results show clearly the wave nature of the dimensionless temperature distribution, Stanton number and the dimensionless entropy change profiles. The non-equilibrium profiles approach the equilibrium profiles as the speed of wave propagation is increased. The results also show that the non-equilibrium temperature is higher than the equilibrium temperature but the difference decreases as the wave propagation speed increases. (Author)

  16. Photonic crystal waveguides with semi-slow light and tailored dispersion properties

    DEFF Research Database (Denmark)

    Frandsen, Lars Hagedorn; Lavrinenko, Andrei; Fage-Pedersen, Jacob

    2006-01-01

    waveguide with either vanishing, positive, or negative group velocity dispersion and semi-slow light. We realize experimentally a silicon-on-insulator photonic crystal waveguide having nearly constant group velocity [similar to]c$-0$//34 in an 11-nm bandwidth below the silica-line. $CPY@2006 Optical Society...

  17. Effects of irrigation and plastic mulch on soil properties on semi-arid abandoned fields

    NARCIS (Netherlands)

    van der Meulen, E.S.; Nol, L.; Cammeraat, L.H.

    2006-01-01

    The Guadalentín Basin in Spain is one of the driest areas of Europe and has problems with high evaporation rates, and high risks of desertification exist including soil quality loss and soil erosion. Farmers in this semi-arid region use polyethylene covers on their irrigated croplands to reduce

  18. Semi-local scaling and turbulence modulation in variable property turbulent channel flows

    NARCIS (Netherlands)

    Patel, A.; Peeters, J.W.R.; Boersma, B.J.; Pecnik, R.

    2015-01-01

    We theoretically and numerically investigate the effect of temperature dependent density and viscosity on turbulence in channel flows. First, a mathematical framework is developed to support the validity of the semi-local scaling as proposed based on heuristic arguments by Huang, Coleman, and

  19. WOOD HEMICELLULOSE/CHITOSAN-BASED SEMI-INTERPENETRATING NETWORK HYDROGELS: MECHANICAL, SWELLING AND CONTROLLED DRUG RELEASE PROPERTIES

    Directory of Open Access Journals (Sweden)

    Muzaffer Ahmet Karaaslan

    2010-04-01

    Full Text Available The cell wall of most plant biomass from forest and agricultural resources consists of three major polymers, cellulose, hemicellulose, and lignin. Of these, hemicelluloses have gained increasing attention as sustainable raw materials. In this study, novel pH-sensitive semi-IPN hydrogels based on hemicelluloses and chitosan were prepared using glutaraldehyde as the crosslinking agent. The hemicellulose isolated from aspen was analyzed for sugar content by HPLC, and its molecular weight distribution was determined by high performance size exclusion chromatography. Results revealed that hemicellulose had a broad molecular weight distribution with a fair amount of polymeric units, together with xylose, arabinose, and glucose. The effects of hemicellulose content on mechanical properties and swelling behavior of hydrogels were investigated. The semi-IPNs hydrogel structure was confirmed by FT-IR, X-ray study, and the ninhydrin assay method. X-ray analysis showed that higher hemicellulose contents yielded higher crystallinity. Mechanical properties were mainly dependent on the crosslink density and average molecular weight between crosslinks. Swelling ratios increased with increasing hemicellulose content and were high at low pH values due to repulsion between similarly charged groups. In vitro release study of a model drug showed that these semi-IPN hydrogels could be used for controlled drug delivery into gastric fluid.

  20. Preparation and Properties of a Novel Semi-IPN Slow-Release Fertilizer with the Function of Water Retention.

    Science.gov (United States)

    Xiang, Yang; Ru, Xudong; Shi, Jinguo; Song, Jiang; Zhao, Haidong; Liu, Yaqing; Guo, Dongdong; Lu, Xin

    2017-12-20

    A new semi-interpenetrating polymer network (semi-IPN) slow-release fertilizer (SISRF) with water absorbency, based on the kaolin-g-poly(acrylic acid-co-acrylic amide) (kaolin-g-P(AA-co-AM)) network and linear urea-formaldehyde oligomers (UF), was prepared by solution polymerization. Nutrients phosphorus and potassium were supplied by adding dipotassium hydrogen phosphate during the preparation process. The structure and properties of SISRF were characterized by various characterization methods. SISRF showed excellent water absorbency of 68 g g -1 in tap water. The slow-release behavior of nutrients and water-retention capacity of SISRF were also measured. Meanwhile, the swelling kinetics was well described by a pseudo-second-order kinetics model. Results suggested the formation of SISRF with simultaneously good slow-release and water-retention capacity, which was expected to apply in modern agriculture and horticulture.

  1. Conduction properties of thin films from a water soluble carbon nanotube/hemicellulose complex

    Science.gov (United States)

    Shao, Dongkai; Yotprayoonsak, Peerapong; Saunajoki, Ville; Ahlskog, Markus; Virtanen, Jorma; Kangas, Veijo; Volodin, Alexander; Van Haesendonck, Chris; Burdanova, Maria; Mosley, Connor D. W.; Lloyd-Hughes, James

    2018-04-01

    We have examined the conductive properties of carbon nanotube based thin films, which were prepared via dispersion in water by non-covalent functionalization of the nanotubes with xylan, a type of hemicellulose. Measurements of low temperature conductivity, Kelvin probe force microscopy, and high frequency (THz) conductivity elucidated the intra-tube and inter-tube charge transport processes in this material. The measurements show excellent conductive properties of the as prepared thin films, with bulk conductivity up to 2000 S cm-1. The transport results demonstrate that the hemicellulose does not seriously interfere with the inter-tube conductance.

  2. Effect of the V{sub As}V{sub Ga} complex defect doping on properties of the semi-insulating GaAs

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Deming, E-mail: xautmdm@163.com; Qiao, Hongbo; Shi, Wei; Li, Enling [Department of Applied Physics, Xi' an University of Technology, Xi' an 710054 (China)

    2014-04-21

    The different position V{sub As}V{sub Ga} cluster defect doping in semi-insulating (SI) GaAs has been studied by first-principles calculation based on hybrid density functional theory. Our calculated results show that EL6 level is formed due to the V{sub As}V{sub Ga} complex defect, which is very close to the experimental result. It provides the explanation of the absorption of laser with the wavelength beyond in semi-insulating GaAs. The formation energy of V{sub As}V{sub Ga} complex defect is found to decrease from surface to interior gradually. The conduction band minima and valence band maxima of GaAs (001) surface with the V{sub As}V{sub Ga} complex defect are all located at Γ point, and some defect levels are produced in the forbidden band. In contrast, the conduction band minima and valence band maxima of GaAs with the interior V{sub As}V{sub Ga} complex defect are not located at the same k-point, so it might involve the change of momentum in the electron transition process. The research will help strengthen the understanding of photoelectronic properties and effectively guide the preparation of the SI-GaAs materials.

  3. Storage properties of gamma-irradiated semi-dried fish varieties

    International Nuclear Information System (INIS)

    Vinh, P.Q.; Alur, M.D.; Nair, P.M.

    1993-01-01

    Several varieties of semi-dried unirradiated and irradiated (1 and 3 kGy) fish, namely, anchovies (Stolephorus commersonii), Bombay duck (Harpodon nehereus), shrimp (Penaeus indicus) and Vietnam scad (Alepes mate) were stored at ambient temperature (26 degree C). During the course of storage, quality characteristics such as total bacterial count (TBC), mould count and biochemical indices of freshness were studied. These studies indicated that initial TBC of semi-dried fish varied from 700-5400 cfu per g of fish, while mould could ranged from 27-1500 cfu per g. However, upon irradiation at 3 kGy, initial bacterial load was considerably reduced. Vietnam scad was not contaminated with mould after 3-5 months of storage at room temperature. Indices such as TVA and TVBN increased during storage at room temperature for both unirradiated and irradiated samples

  4. Fluctuation theory for transport properties in multicomponent mixtures: thermodiffusion and heat conductivity

    DEFF Research Database (Denmark)

    Shapiro, Alexander

    2004-01-01

    The theory of transport properties in multicomponent gas and liquid mixtures, which was previously developed for diffusion coefficients, is extended onto thermodiffusion coefficients and heat conductivities. The derivation of the expressions for transport properties is based on the general statis...... of the heat conductivity coefficient for ideal gas. (C) 2003 Elsevier B.V. All rights reserved.......The theory of transport properties in multicomponent gas and liquid mixtures, which was previously developed for diffusion coefficients, is extended onto thermodiffusion coefficients and heat conductivities. The derivation of the expressions for transport properties is based on the general...

  5. Mathematical properties of a semi-classical signal analysis method: Noisy signal case

    KAUST Repository

    Liu, Dayan

    2012-08-01

    Recently, a new signal analysis method based on a semi-classical approach has been proposed [1]. The main idea in this method is to interpret a signal as a potential of a Schrodinger operator and then to use the discrete spectrum of this operator to analyze the signal. In this paper, we are interested in a mathematical analysis of this method in discrete case considering noisy signals. © 2012 IEEE.

  6. Prediction of mechanical properties by means of semi-destructive methods: a review

    Czech Academy of Sciences Publication Activity Database

    Kloiber, Michal; Drdácký, Miloš; Machado, J. S.; Piazza, M.; Yamaguchi, N.

    2015-01-01

    Roč. 101, SI (2015), s. 1215-1234 ISSN 0950-0618 R&D Projects: GA MK(CZ) DF11P01OVV001; GA MŠk(CZ) LO1219 Keywords : semi-destructive testing * wood * in situ assessment * strength * resistance Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 2.421, year: 2015 http://www.sciencedirect.com/science/article/pii/S0950061815006923

  7. Mathematical properties of a semi-classical signal analysis method: Noisy signal case

    KAUST Repository

    Liu, Dayan; Laleg-Kirati, Taous-Meriem

    2012-01-01

    Recently, a new signal analysis method based on a semi-classical approach has been proposed [1]. The main idea in this method is to interpret a signal as a potential of a Schrodinger operator and then to use the discrete spectrum of this operator to analyze the signal. In this paper, we are interested in a mathematical analysis of this method in discrete case considering noisy signals. © 2012 IEEE.

  8. Effect of fat types on the structural and textural properties of dough and semi-sweet biscuit.

    Science.gov (United States)

    Mamat, Hasmadi; Hill, Sandra E

    2014-09-01

    Fat is an important ingredient in baking products and it plays many roles in providing desirable textural properties of baking products, particularly biscuit. In this study, the effect of fat types on dough rheological properties and quality of semi-sweet biscuit (rich tea type) were investigated using various techniques. Texture profile and extensibility analysis were used to study the dough rheology, while three-point bend test and scanning electron microscopy were used to analyse the textural characteristics of final product. TPA results showed that the type of fat significantly influenced dough textural properties. Biscuit produced with higher solid fat oil showed higher breaking force but this was not significantly different when evaluated by sensory panel. Scanning electron microscopy showed that biscuit produced with palm mid-fraction had an open internal microstructure and heterogeneous air cells as compared to other samples.

  9. The Reliability of Technical and Tactical Tagging Analysis Conducted by a Semi-Automatic VTS in Soccer.

    Science.gov (United States)

    Beato, Marco; Jamil, Mikael; Devereux, Gavin

    2018-06-01

    The Video Tracking multiple cameras system (VTS) is a technology that records two-dimensional position data (x and y) at high sampling rates (over 25 Hz). The VTS is of great interest because it can record external load variables as well as collect technical and tactical parameters. Performance analysis is mainly focused on physical demands, yet less attention has been afforded to technical and tactical factors. Digital.Stadium® VTS is a performance analysis device widely used at national and international levels (i.e. Italian Serie A, Euro 2016) and the reliability evaluation of its technical tagging analysis (e.g. shots, passes, assists, set pieces) could be paramount for its application at elite level competitions, as well as in research studies. Two professional soccer teams, with 30 male players (age 23 ± 5 years, body mass 78.3 ± 6.9 kg, body height 1.81 ± 0.06 m), were monitored in the 2016 season during a friendly match and data analysis was performed immediately after the game ended. This process was then replicated a week later (4 operators conducted the data analysis in each week). This study reports a near perfect relationship between Match and its Replication. R2 coefficients (relationships between Match and Replication) were highly significant for each of the technical variables considered (p technical tagging data accurately.

  10. Synthesis and properties of hemicelluloses-based semi-IPN hydrogels.

    Science.gov (United States)

    Peng, Feng; Guan, Ying; Zhang, Bing; Bian, Jing; Ren, Jun-Li; Yao, Chun-Li; Sun, Run-Cang

    2014-04-01

    Hemicelluloses were extracted from holocellulose of bamboo by alkaline treatment. The phosphorylated poly(vinyl alcohol) (P-PVA) samples with various substitution degrees were prepared through the esterification of PVA and phosphoric acid. A series of hydrogels of semi-interpenetrating polymeric networks (semi-IPN) composed of hemicelluloses-g-poly(acrylic acid) (HM-g-PAA) and the phosphorylated poly(vinyl alcohol) (P-PVA) were prepared by radical polymerization using potassium persulphate (KPS) as initiator. The HM-g-PAA networks were crosslinked by N,N-methylenebisacrylamide (MBA) as a crosslinking agent in the presence of linear P-PVA. FT-IR results confirmed that the hydrogels comprised a porous crosslink structure of P-PVA and HM with side chains that carried carboxylate and phosphorylate groups. SEM observations indicated that the incorporation of P-PVA induced highly porous structure, and P-PVA was uniformly dispersed in the polymeric network. The interior network structures of the semi-IPN matrix became more porous with increasing P-PVA. The TGA results showed that the thermo-decomposing temperature and thermal stability were increased effectively for intruding the chain of P-PVA. The maximum equilibrium swelling ratio of hydrogels in distilled water and 0.9 wt% sodium chloride solutions was up to 1085 g g(-1) and 87 g g(-1), respectively. The compressive strength increased with increasing the MBA/HM and P-PVA/HM ratios, and decreased with the increment of AA/HM ratio. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Information content of slug tests for estimating hydraulic properties in realistic, high-conductivity aquifer scenarios

    Science.gov (United States)

    Cardiff, Michael; Barrash, Warren; Thoma, Michael; Malama, Bwalya

    2011-06-01

    SummaryA recently developed unified model for partially-penetrating slug tests in unconfined aquifers ( Malama et al., in press) provides a semi-analytical solution for aquifer response at the wellbore in the presence of inertial effects and wellbore skin, and is able to model the full range of responses from overdamped/monotonic to underdamped/oscillatory. While the model provides a unifying framework for realistically analyzing slug tests in aquifers (with the ultimate goal of determining aquifer properties such as hydraulic conductivity K and specific storage Ss), it is currently unclear whether parameters of this model can be well-identified without significant prior information and, thus, what degree of information content can be expected from such slug tests. In this paper, we examine the information content of slug tests in realistic field scenarios with respect to estimating aquifer properties, through analysis of both numerical experiments and field datasets. First, through numerical experiments using Markov Chain Monte Carlo methods for gauging parameter uncertainty and identifiability, we find that: (1) as noted by previous researchers, estimation of aquifer storage parameters using slug test data is highly unreliable and subject to significant uncertainty; (2) joint estimation of aquifer and skin parameters contributes to significant uncertainty in both unless prior knowledge is available; and (3) similarly, without prior information joint estimation of both aquifer radial and vertical conductivity may be unreliable. These results have significant implications for the types of information that must be collected prior to slug test analysis in order to obtain reliable aquifer parameter estimates. For example, plausible estimates of aquifer anisotropy ratios and bounds on wellbore skin K should be obtained, if possible, a priori. Secondly, through analysis of field data - consisting of over 2500 records from partially-penetrating slug tests in a

  12. Effects of irrigation and plastic mulch on soil properties on semi-arid abandoned fields

    OpenAIRE

    van der Meulen, E.S.; Nol, L.; Cammeraat, L.H.

    2006-01-01

    The Guadalentín Basin in Spain is one of the driest areas of Europe and has problems with high evaporation rates, and high risks of desertification exist including soil quality loss and soil erosion. Farmers in this semi-arid region use polyethylene covers on their irrigated croplands to reduce evaporation in order to enhance crop yield. When farmers abandon the acres, they leave the plastic covers on the fields. Up to now research has been concentrating on the effects of plastic covers on cr...

  13. Novel electrical transport properties in conducting polymers such as polythiophene and Poly(3-Methylthiophene)

    International Nuclear Information System (INIS)

    Kazama, Shigeo; Masubuchi, Shin-ichi; Matsuyama, Tomochika; Matsushita, Rokuji.

    1994-01-01

    Electric transport properties in most of the conducting organic polymers have provided a riddle that prevents a thorough physical understanding of the conduction mechanism. Major difficulties for approaching the most substantial aspect in the electrical transport properties underlie in complicated higher order structure inherent to polymeric materials consisting of crystalline regions entangled with disordered amorphous regions. In order to clearly understand the origin of the metallic nature of conducting polymers, we have to extract the proper transport properties characteristics of the ordered crystalline regions. We have made a series of experimental studies of the transport properties in conductive polythiophene and poly(3-methylthiophene) obtained with the electrochemical polymerization. For polythiophene, we have investigated both the as-grown samples and the ones that contain controlled amount of dopant species exchanged after the neutralization aiming to see the effect of dopant concentration on the transport properties. (author)

  14. Control of Transboundary Movement of Radioactive Material Inadvertently Incorporated into Scrap Metal and Semi-finished Products of the Metal Recycling Industries. Results of the Meetings Conducted to Develop a Draft Code of Conduct

    International Nuclear Information System (INIS)

    2014-02-01

    In 2010, the IAEA initiated the development of a code of conduct on the transboundary movement of radioactive material inadvertently incorporated into scrap metal and semi- finished products of the metal recycling industries (Metal Recycling Code of Conduct). The Metal Recycling Code of Conduct was intended to harmonize the approaches of Member States in relation to the discovery of radioactive material that may inadvertently be present in scrap metals and semi-finished products subject to transboundary movement, and their safe handling and management to facilitate regulatory control. The Metal Recycling Code of Conduct was envisaged as being complementary to the Safety Guide on Control of Orphan Sources and Other Radioactive Material in the Metal Recycling and Production Industries (IAEA Safety Standards Series No. SSG-17), which provides recommendations, principally within a national context, on the protection of workers, members of the public and the environment in relation to the control of radioactive material inadvertently incorporated in scrap metal. In February 2013, the third open-ended meeting of technical and legal experts to develop the Metal Recycling Code of Conduct was organized. The objective of this meeting was to address the comments received from Member States and to finalize the text of the draft Metal Recycling Code of Conduct. Representatives from 55 Member States, one non-Member State and the EU, together with seven observers from the metal recycling industry, reviewed the comments and revised the draft accordingly. In September 2013, in Resolution GC(57)/RES/9, the IAEA General Conference recorded that it 'Appreciates the intensive efforts undertaken by the Secretariat to develop a code of conduct on the transboundary movement of scrap metal, or materials produced from scrap metal, that may inadvertently contain radioactive material, and encourages the Secretariat to make the results of the discussion conducted on this issue available to

  15. Semi-structured Interview Measure of Stigma (SIMS) in psychosis: Assessment of psychometric properties.

    Science.gov (United States)

    Wood, Lisa; Burke, Eilish; Byrne, Rory; Enache, Gabriela; Morrison, Anthony P

    2016-10-01

    Stigma is a significant difficulty for people who experience psychosis. To date, there have been no outcome measures developed to examine stigma exclusively in people with psychosis. The aim of this study was develop and validate a semi-structured interview measure of stigma (SIMS) in psychosis. The SIMS is an eleven item measure of stigma developed in consultation with service users who have experienced psychosis. 79 participants with experience of psychosis were recruited for the purposes of this study. They were administered the SIMS alongside a battery of other relevant outcome measures to examine reliability and validity. A one-factor solution was identified for the SIMS which encompassed all ten rateable items. The measure met all reliability and validity criteria and illustrated good internal consistency, inter-rater reliability, test retest reliability, criterion validity, construct validity, sensitivity to change and had no floor or ceiling effects. The SIMS is a reliable and valid measure of stigma in psychosis. It may be more engaging and acceptable than other stigma measures due to its semi-structured interview format. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

  16. Surface profile gradient in amorphous Ta{sub 2}O{sub 5} semi conductive layers regulates nanoscale electric current stability

    Energy Technology Data Exchange (ETDEWEB)

    Cefalas, A.C., E-mail: ccefalas@eie.gr [National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vassileos Constantinou Avenue, Athens 11635 (Greece); Kollia, Z.; Spyropoulos-Antonakakis, N.; Gavriil, V. [National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vassileos Constantinou Avenue, Athens 11635 (Greece); Christofilos, D.; Kourouklis, G. [Physics Division, School of Technology, Aristotle University of Thessaloniki, Thessaloniki 54124 (Greece); Semashko, V.V.; Pavlov, V. [Kazan Federal University, Institute of Physics, 18 Kremljovskaja str., Kazan 420008 (Russian Federation); Sarantopoulou, E. [National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vassileos Constantinou Avenue, Athens 11635 (Greece); Kazan Federal University, Institute of Physics, 18 Kremljovskaja str., Kazan 420008 (Russian Federation)

    2017-02-28

    Highlights: • The work links the surface morphology of amorphous semiconductors with both their electric-thermal properties and current stability at the nanoscale (<1 μm). • Measured high correlation value between surface morphological spatial gradient and conductive electron energy spatial gradient or thermal gradient. • Unidirectional current stability is associated with asymmetric nanodomains along nanosize conductive paths. • Bidirectional current stability is inherent with either long conductive paths or nanosize conductive paths along symmetric nanodomains. • Conclusion: Surface design improves current stability across nanoelectonic junctions. - Abstract: A link between the morphological characteristics and the electric properties of amorphous layers is established by means of atomic, conductive, electrostatic force and thermal scanning microscopy. Using amorphous Ta{sub 2}O{sub 5} (a-Ta{sub 2}O{sub 5}) semiconductive layer, it is found that surface profile gradients (morphological gradient), are highly correlated to both the electron energy gradient of trapped electrons in interactive Coulombic sites and the thermal gradient along conductive paths and thus thermal and electric properties are correlated with surface morphology at the nanoscale. Furthermore, morphological and electron energy gradients along opposite conductive paths of electrons intrinsically impose a current stability anisotropy. For either long conductive paths (L > 1 μm) or along symmetric nanodomains, current stability for both positive and negative currents i is demonstrated. On the contrary, for short conductive paths along non-symmetric nanodomains, the set of independent variables (L, i) is spanned by two current stability/intability loci. One locus specifies a stable state for negative currents, while the other locus also describes a stable state for positive currents.

  17. Thermo-sensitive and swelling properties of cellouronic acid sodium/poly (acrylamide-co-diallyldimethylammonium chloride) semi-IPN.

    Science.gov (United States)

    Zhang, Heng; Gao, Xin; Chen, Keli; Li, Hui; Peng, Lincai

    2018-02-01

    In current study, cellouronic acid sodium (CAS), obtained from bagasse pith, has been introduced into poly(acrylamide-co-diallyldimethylammonium chloride) (poly(AM-co-DAC)) network to form novel thermo-sensitive semi-IPNs. The structure and morphology of the hydrogels were proved by Fourier transformation infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The effects of CAS content, initiator charge, cross-linker dosage and swelling-medium property on the thermo-responsive water absorptivity were investigated in detail. The results elucidated that the prepared gels exhibited a thermo-sensibility with an upper critical solution temperature (UCST) and a high water-absorbency. And the values of UCST and equilibrium swelling ratio largely depended on the inner structure of the semi-IPNs and the external solvent property. It was also revealed that the swelling process conformed to the Schott's pseudo second order model and diffusion type was non-Fickian diffusion. The value of activation energy for this polyelectrolyte was found to be 8.74kJ/mol. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Mechanical and solubility properties of bio-nanocomposite film of semi refined kappa carrageenan/ZnO nanoparticles

    Science.gov (United States)

    Saputri, Apriliana Eka; Praseptiangga, Danar; Rochima, Emma; Panatarani, Camellia; Joni, I. Made

    2018-02-01

    The aim of this present work is to develop semi refined kappa carrageenan based bio-nanocomposite film as an alternative to synthetic petroleum based food packaging materials. Among natural polymers, carrageenan is one of the most promising material, since it is a renewable bioresource. The ZnO nanoparticles (0.5%; 1.0%; 1.5% w/w carrageenan) was incorporated into carrageenan polymer to prepare bio-nanocomposite films, where ZnO acts as reinforcement for carrageenan matrix. The mechanical and solubility properties of the prepared films were investigated as a function of ZnO concentration. The results indicated that the addition of ZnO exhibits greater solubility compared to the neat film. The elongation at break is insignificantly different on the films with and without addition ZnO. The tensile strength of the film was highest for the sample with 0.5% ZnO. These mechanical and solubility properties suggest that bio-nanocomposite film of semi refined kappa carrageenan and nanoparticle ZnO can be effectively used as food packaging material.

  19. Effect of microparticulated whey protein on sensory properties of liquid and semi-solid model foods

    NARCIS (Netherlands)

    Liu, K.; Stieger, M.A.; Linden, van der E.; Velde, van de Fred

    2016-01-01

    This work describes the sensory properties of microparticulated whey protein (MWP) particles in relation to their rheological and tribological properties. The aim of this work is to obtain a better understanding of the sensory perception of MWP particles compared to oil droplets in liquid and

  20. Electrical properties of conducting loads produced from polyaniline deposited in natural fibers and nanoclays

    International Nuclear Information System (INIS)

    Kosenhoski, Dirlaine; Saade, Wesley; Pinto, Camila P.; Becker, Daniela; Dalmolin, Carla; Pachekoski, Wagner M.

    2015-01-01

    Conducting polymers are known for their excellent magnetic and electrical properties, but they still are an expensive and limited choice to their use as a conducting load for composite materials. An alternative to optimize the electrical conductivity of polymeric composites is the deposition of a conducting polymer on materials already used as loads, as the deposition on natural fibers or the encapsulation of polymeric chains in the voids of host structures. In this work, bananastem fiber and montmorillonite nanoclay (MMT) were used as host structures for polyaniline synthesis in order to produce conducting loads. Samples were characterized by FT-IR and X-Rays Diffraction in order to confirm the formation of polyanilina / bananastem fibers or polyanilina / nanoclays loads. Influence on the electrical properties of the composites were evaluated by Electrochemical Impedance Spectroscopy (EIS), showing the maintenance of the electric conductivity of polyaniline and its potential use as a load for the formation of conducting composites. (author)

  1. Saturated hydraulic conductivity in relation to physical properties of soils in the Nsukka Plains, SE Nigeria

    International Nuclear Information System (INIS)

    Mbagwu, J.S.C.

    1994-05-01

    The objective of the study is to develop and validate statistical models for estimating the saturated hydraulic conductivity of soils with high water intake rates from more easily-determined properties and to test the hypothesis that it is equal to Philip transmissivity term and the steady infiltration rate. The results of the study show that the dominant physical property influencing saturated hydraulic conductivity of the investigated soils is the macroporosity. 37 refs, 6 figs, 5 tabs

  2. Solid-state poly(ethylene glycol)-polyurethane/polymethylmethacrylate/rutile TiO2 nanofiber composite electrolyte-correlation between morphology and conducting properties

    International Nuclear Information System (INIS)

    Chilaka, Naresh; Ghosh, Sutapa

    2012-01-01

    Highlights: ► Semi IPN composite of PEG-PU/PMMA with different wt% of rutile TiO 2 is synthesized. ► Formation of nanocomposite is confirmed by SEM, XRD and IR spectroscopic analysis. ► DSC and TGA confirmed the enhanced thermal stability of the composite. ► Composite with 18 wt% rutile TiO 2 is found to be the best conducting material. - Abstract: A series of lithium electrolyte materials based on hybrid of semi Inter penetrating Polymer Network of [poly(ethylene glycol)-polyurethane-polymethylmethacrylate] [60:40] and TiO 2 nanofibers is described. TiO 2 nanofibers are made by simple solvothermal procedure. Rutile phase of TiO 2 and its fibrous morphology are confirmed by X-ray diffraction pattern and scanning electron microscopy image respectively. Semi Inter penetrating Polymer Network of polyethylene glycol-polyurethane/polymethylmethacrylate with LiClO 4 and its nanocomposite with different weight percent of TiO 2 nano fibers have been synthesized. The formation of Inter penetrating Polymer Network and its amorphous nature are confirmed by Fourier transform infrared spectra, X-ray diffraction pattern and differential scanning calorimetry results. Thermo gravimetric analysis shows enhanced thermal stability of the composite compared to the semi Inter penetrating Polymer Network system. The electrical characterizations of the nanocomposites are done by current–voltage (I–V) measurements and impedance spectroscopy. These results confirm that incorporation of TiO 2 nanofibers by 18% enhances the conductivity of the Inter penetrating Polymer Network system by ten times . The nanoscale structure of the inorganic material is found to be responsible for the bulk properties of the system, especially those that differ from the properties of similar, pure salt-in-polymer electrolytes. Further differential scanning calorimetry, scanning electron microscopy and impedance data confirm the presence of two polymeric phases in the semi Inter penetrating Polymer

  3. Analysis of the variability of some properties of a semi-deciduous forest soil

    International Nuclear Information System (INIS)

    Okae-Anti, D.; Ogoe, J.I.

    2003-05-01

    The formation of soils in any region is influenced by many factors such as the parent materials and the secondary materials derived from them, the vegetation and the history of land use. These factors vary from place to place and they contribute to the spatial variation in properties of the soil. Quantification of the magnitude, location and causes of spatial variability is an essential but insufficient ingredient of soil surveys. We took soil samples from the 0-20 cm depth covering soils in the Asuansi-Akroso-Nta-Ofin compound association (Lixisol, Cambisol and Fluvisol association) at the study site, following the nested balanced hierarchical sampling technique. This covered distances between 100 and 0.80 m. Standard laboratory analyses were performed to quantify the selected properties, namely, pH, organic carbon, total nitrogen, total phosphorus, exchangeable potassium and content of sand, silt and clay. Classical statistics and geostatistical procedures were performed on the data and models fitted to the variability patterns. Physical and the more stable properties such as sand, silt and clay were fitted with spherical variogram models. These models indicate a high level of spatial dependence and therefore such properties may be said to be fairly stable in the field. On the contrary, chemical properties such as exchangeable potassium, were fitted with exponential variogram models, indicating that these properties were less stable and showed dependence over longer distances. The scale of variation of the properties ranged between 35 m - 62 m. The degree of uncertainty associated with time and space can be reduced by improved documentation of field variability using the tools of geostatistics. (author)

  4. Damping properties of non-conductive composite materials for applications in power transmission pylons

    DEFF Research Database (Denmark)

    Kliem, Mathias; Rüppel, Marvin; Høgsberg, Jan

    2018-01-01

    This study aims to characterize the fibre direction dependent damping properties of non-conductive composite materialsto be used in newly designed electrical power transm°ission pylons, on which the conducting cables will be directlyconnected. Thus, the composite structure can be designed both to...

  5. FY 2000 report on the results of the R and D of fundamental technologies for semi conductivity applications; 2000 nendo chodendo oyo kiban gijutsu kenkyu kaihatsu seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-05-01

    In relation to the project on the R and D of fundamental technologies for semi conductivity applications, the FY 2000 results were summed up. As to the study of the high temperature superconductivity mechanism, it was found out that a theoretical model of the strong scattering limit in d-wave superconductor can be used for the breaking of superconductivity due to Zn impurities. Concerning the study of the critical current mechanism, the elucidation was proceeded with of the magnetic flux pinning and grain-boundary conduction mechanism. Relating to the development of element technology of bulks with great electromagnetic force, the mechanical strength of superconducting bulk materials was raised to 100MPa or more by the epoxy resin impregnation method. As to the development of the basic technology for fabrication of high next-generation current conductors, the expansion was confirmed of conditions for growing single grains in the zone-melt process for very fine filaments. About the development of technology of single crystal substrates, in the development of the pseudo single crystalline film growth process by LPE method, a yield ratio of high quality crystal of 63% was achieved. Concerning the development of technology of thin film/multi-layer, the area of uniform composition/thickness of NdBa{sub 2}Cu{sub 3}O{sub 7-x} MOCVD films was enlarged up to 20mm square. (NEDO)

  6. Numerical studies of heat transfer by simultaneous radiative-conduction and radiative-convection in a two dimensional semi-transparent medium

    International Nuclear Information System (INIS)

    Draoui, Abdeslam

    1989-01-01

    The works we present here are on numerical approaches of heat transfer coupling radiation-conduction and radiation-convection within semi-transparent two-dimensional medium. The first part deals with a review of equations of radiative transfer and introduces three numerical methods (Pl, P3, Hottel's zones) which enable one to solve this problem in a two-dimensional environment. After comparing the three methods in the case where radiation is the only mode of transfer, we introduce in the second chapter a study of the coupling of radiation with conduction. So, a fourth method is used to solve this problem. These comparisons lead us to various methods which enable us to show the interest of the spherical harmonics approximations. In the third part, the Pl approximation is kept because it is simple to use, moreover it enables us to introduce both the coupling of radiative transfers with laminar convective equations in a thermally driven two-dimensional cavity. The results show a significant influence of the radiative participation of the fluid on heat and dynamic transfer we met in this type of problem. (author) [fr

  7. Electrical properties and conduction mechanism of [C2H5NH3]2CuCl4 compound

    Science.gov (United States)

    Mohamed, C. Ben; Karoui, K.; Jomni, F.; Guidara, K.; Rhaiem, A. Ben

    2015-02-01

    The [(C2H5)NH3]2CuCl4 compound was prepared and characterized by several technique: the X-ray powder diffraction confirms the purity of the synthetized compound, the differential scanning calorimetric show several phase transitions at 236 K, 330 K, 357 K and 371 K, the dialectical properties confirms the ferroelectric-paraelectric phase transition at 238 K, which is reported by V. Kapustianyk et al. (2007) [1]. The two semi-circles observed in the complex impedance identify the presence of the grain interior and grain boundary contributions to the electrical response in this material. The equivalent circuit is modeled by a combination series of two parallel RP-CPE circuits. The temperature dependence of the alternative current conductivity (σg) and direct current conductivity (σdc) confirm the observed transitions in the calorimetric study. The (AC) electrical conduction in [(C2H5)NH3]2CuCl4 was studied by two processes that can be attributed to a hopping transport mechanism: the non-overlapping small polaron tunneling (NSPT) model in phase III and the correlated barrier hopping (CBH) model in phases I, II, IV, V and VI.

  8. Effect of ionizing radiation on structural and conductive properties of copper nanotubes

    Science.gov (United States)

    Zdorovets, M. V.; Borgekov, D. B.; Kenzhina, I. E.; Kozlovskiy, A. L.

    2018-01-01

    The use of electron radiation is an effective tool for stimulating a controlled modification of structural and conductive properties of nanomaterials in modern materials science. The paper presents the results of studies of the influence of various types of radiation on structural and conductive properties of copper nanotubes obtained by electrochemical synthesis in pores of templates based on polyethylene terephthalate. Such methods as SEM, X-ray diffraction and EDS show that irradiation with a stream of high-energy electrons with doses of 50-250 kGy makes it possible to modify the crystal structure of nanotubes, increasing their conductivity and decreasing the resistance of nanostructures without destroying the structure.

  9. Synthesis of the semi-organic nonlinear optical crystal l-glutamic acid zinc chloride and investigation of its growth and physiochemical properties

    Directory of Open Access Journals (Sweden)

    S. Chennakrishnan

    2017-11-01

    Full Text Available The aim of this study is to synthesize and investigate the growth and physiochemical properties of the nonlinear optical semi-organic crystal l-glutamic acid zinc chloride (LGAZC. An optically transparent and defect-free crystal was grown with the slow evaporation solution growth technique under optimized conditions. The induction periods were measured at various supersaturations, and the interfacial energies were evaluated. Single crystal X-ray diffraction reveals that the crystal has an orthorhombic structure with space group P212121, and the calculated lattice parameters are a = 5.20 Å, b = 6.99 Å, c = 17.58 Å, α = β = γ = 90° and volume = 623.411 Å3. Spectroscopic properties were investigated by recording the Fourier transform infrared and optical transmission spectra. The thermal decomposition of the grown crystal was investigated by Thermo Gravimetric and Differential Thermal Analysis (TG/DTA. The LGAZC crystal exhibits second harmonic generation (SHG efficiency 1.5 times that of inorganic KDP crystal. The presence of the metal ion (Zn+ in a grown crystal was identified by EDAX spectrum analysis. The photoconductivity study demonstrates that LGAZC crystal has a positive photo conducting nature. The dielectric response of the LGAZC crystal was investigated and reported. Keywords: Semi-organic nonlinear optical crystal, X-ray Diffraction, UV-vis-NIR, Thermal study

  10. Fabrication and properties of shape-memory polymer coated with conductive nanofiber paper

    Science.gov (United States)

    Lu, Haibao; Liu, Yanju; Gou, Jan; Leng, Jinsong

    2009-07-01

    A unique concept of shape-memory polymer (SMP) nanocomposites making up of carbon nanofiber paper was explored. The essential element of this method was to design and fabricate nanopaper with well-controlled and optimized network structure of carbon nanofibers. In this study, carbon nanofiber paper was prepared under ultrasonicated processing and vapor press method, while the dispersion of nanofiber was treated by BYK-191 dispersant. The morphologies of carbon nanofibers within the paper were characterized with scanning electron microscopy (SEM). In addition, the thermomechanical properties of SMP coated with carbon nanofiber paper were measured by the dynamic mechanical thermal analysis (DMTA). It was found that the glass transition temperature and thermomechanical properties of nanocomposites were strongly determined by the dispersion of polymer in conductive paper. Subsequently, the electrical conductivity of conductive paper and nanocomposites were measured, respectively. And experimental results revealed that the conductive properties of nanocoposites were significantly improved by carbon nanopaper, resulting in actuation driven by electrical resistive heating.

  11. The porosity effect on properties of sintered materials as their conductivity and Youngs modulus of elasticity

    International Nuclear Information System (INIS)

    Ondracek, G.; Thuemmler, F.

    1979-01-01

    A set of equations derived demonstrates quantitatively the influence of closed pores on the conductivity as well as on Youngsmodulus of elasticity of sintered materials. There are three microstructural parameters following from the theoretical derivation controlling the porosity effect on the properties, which are the total porosity, the form factor and the orientation factor of the pores. By quantitative microstructure analysis these factors become available providing together with the equations the tool - to calculate the conductivity and Youngs modulus of elasticity from microstructural quantities of sintered materials thus substituting direct property measurements by quantitative microstructure analysis if desired - to endeaver technologically optimum microstructures to obtain theoretically predicted special property values and to precalculate property alterations by microstructure variations ('taylor-made-materials') - to supplement the conventional microstructural quality control by calculated property data. (orig.) [de

  12. Semi-Continuous Fermentation of Onion Vinegar and Its Functional Properties.

    Science.gov (United States)

    Lee, Sulhee; Lee, Jin-A; Park, Gwi-Gun; Jang, Jae-Kweon; Park, Young-Seo

    2017-08-08

    For the fermentation of vinegar using onion, acetic acid bacteria and yeast strains with high fermentation ability were screened. Among them, Saccharomyces cerevisiae 1026 was selected as a starter for ethanol production and Acetobacter orientalis MAK88 was selected as a vinegar producer. When the two-stage fermentation of onion vinegar was performed at 28 °C, the titratable acidity reached 4.80% at 24 h of fermentation. When semi-continuous fermentation proceeded to charge-discharge consisting of three cycles, the acetic acid content reached 4.35% at 48 h of fermentation. At this stage, the fermentation efficiency, acetic acid productivity, and specific product formation rate were 76.71%, 17.73 g/(L·d), and 20.58 g/(g·h), respectively. The process in this study significantly reduced the fermentation time and simplified the vinegar production process. The content of total flavonoids and total polyphenols in onion vinegar were 104.36 and 455.41 μg/mL, respectively. The antioxidant activities of onion vinegar in terms of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic) acid (ABTS⁺) radical scavenging activity, and reducing power were 75.33%, 98.88%, and 1.28, respectively. The nitrite scavenging abilities of onion vinegar were 95.38 at pH 1.2. The onion vinegar produced in this study showed higher organoleptic acceptability than commercial onion vinegar.

  13. Dielectric properties of semi-insulating Fe-doped InP in the terahertz spectral region.

    Science.gov (United States)

    Alyabyeva, L N; Zhukova, E S; Belkin, M A; Gorshunov, B P

    2017-08-04

    We report the values and the spectral dependence of the real and imaginary parts of the dielectric permittivity of semi-insulating Fe-doped InP crystalline wafers in the 2-700 cm -1 (0.06-21 THz) spectral region at room temperature. The data shows a number of absorption bands that are assigned to one- and two-phonon and impurity-related absorption processes. Unlike the previous studies of undoped or low-doped InP material, our data unveil the dielectric properties of InP that are not screened by strong free-carrier absorption and will be useful for designing a wide variety of InP-based electronic and photonic devices operating in the terahertz spectral range.

  14. Magnetic properties of a ferromagnet spin-S, Ising, XY and Heisenberg models semi-infinites systems

    International Nuclear Information System (INIS)

    Masrour, R.; Hamedoun, M.; Hourmatallah, A.; Bouslykhane, K.; Benzakour, N.

    2008-01-01

    The magnetic properties of a ferromagnet spin-S a disordered semi-infinite system with a face-centered cubic lattice are investigated using the high-temperature series expansions technique extrapolated with Pade approximants method for Heisenberg, XY and Ising models. The reduced critical temperature of the system τ c =(k B T c )/(2S(S+1)J b ) is studied as function of the thickness of the film and the exchange interactions in the bulk, and within the surfaces J b ,J s and J perpendicular , respectively. It is found that τ c increases with the exchange interactions of surface. The magnetic phase diagrams (τ c versus the dilution x) and the percolation threshold are obtained

  15. The influence of guar gum on textural and sensory properties of rolls made from semi-finished frozen products

    Directory of Open Access Journals (Sweden)

    Pavlína Boudová Pečivová

    2014-07-01

    Full Text Available Textural and sensory properties of rolls produced from semi-finished frozen products with additions of guar gum were assessed. A commercial wheat flour T 512, ingredients such as yeast Saccharomyces cerevisiae, rapeseed oil, sodium chloride were used for preparing dough and final products. Guar gum and commercial additive Trial RC2 were used as additives for production. The textural properties of rolls were measured by a TA-XT Plus Texture Analyzer. All samples were evaluated by selected assessors. A five-point hedonic scale was used for evaluation characteristics such as taste, pliancy, texture, porosity, stickiness, gumminess, crispness and quality. The obtained data showed nonsignificant difference in moisture of rolls after baking and 3 days after baking. Control sample of rolls had higher firmness in comparison to other samples with guar gum after baking. Samples of rolls with higher addition of guar gum (10 g.kg-1 and 15 g.kg-1 had less firmness in comparison to control sample and sample with 5 g.kg-1 of guar gum. Sensory analysis showed negligible differences among all samples in monitored characteristics. Sensory assessors evaluated all samples as identical. Increased addition of guar gum in rolls led to the extension of shelf life (lower firmness at unchanged sensory properties of the rolls.

  16. Synthesis, growth, structure, mechanical and optical properties of a new semi-organic 2-methyl imidazolium dihydrogen phosphate single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Nagapandiselvi, P., E-mail: nagapandiselvip@ssn.edu.in [Department of Physics, SSN College of Engineering, Kalavakkam (India); Baby, C. [Sophisticated Analytical Instrument Facility, Indian Institute of Technology Madras, Chennai (India); Gopalakrishnan, R. [Crystal Research Lab, Department of Physics, Anna University, Chennai (India)

    2016-09-15

    Highlights: • 2MIDP crystals were grown by slow evaporation solution growth technique. • Single crystal XRD revealed self-assembled supramolecular framework. • Z scan technique is employed for third order nonlinear optical susceptibility. • Structure-property correlation is established. - Abstract: A new semi-organic compound, 2-methyl imidazolium dihydrogen phosphate (2MIDP), was prepared and good quality single crystals of 2MIDP were grown by slow evaporation solution growth technique. Crystal structure elucidated using Single crystal XRD showed that 2MIDP crystallizes in monoclinic system with P2{sub 1}/c space group. FT-IR, UV-Vis-NIR, Fluorescence and FT-NMR spectra confirm the molecular structure of 2MIDP. The UV-Vis-NIR spectra established the suitability of the compound for NLO applications. TG-DSC showed that 2MIDP is thermally stable up to 200 °C. Mechanical characteristics like hardness number (H{sub v}), stiffness constant (C{sub 11}), yield strength (σ{sub v}), fracture toughness (K{sub c}) and brittleness index (B{sub i}) were assessed using Vicker’s microhardness tester. Third order nonlinear optical properties determined from Z-scan measurement using femto and picosecond lasers showed two photon reverse saturable absorption. The enhancement of nonlinear optical properties in femto second laser, revealed the suitability of 2MIDP for optical limiting applications.

  17. Semi-analytic models for the CANDELS survey: comparison of predictions for intrinsic galaxy properties

    International Nuclear Information System (INIS)

    Lu, Yu; Wechsler, Risa H.; Somerville, Rachel S.; Croton, Darren; Porter, Lauren; Primack, Joel; Moody, Chris; Behroozi, Peter S.; Ferguson, Henry C.; Koo, David C.; Guo, Yicheng; Safarzadeh, Mohammadtaher; White, Catherine E.; Finlator, Kristian; Castellano, Marco; Sommariva, Veronica

    2014-01-01

    We compare the predictions of three independently developed semi-analytic galaxy formation models (SAMs) that are being used to aid in the interpretation of results from the CANDELS survey. These models are each applied to the same set of halo merger trees extracted from the 'Bolshoi' high-resolution cosmological N-body simulation and are carefully tuned to match the local galaxy stellar mass function using the powerful method of Bayesian Inference coupled with Markov Chain Monte Carlo or by hand. The comparisons reveal that in spite of the significantly different parameterizations for star formation and feedback processes, the three models yield qualitatively similar predictions for the assembly histories of galaxy stellar mass and star formation over cosmic time. Comparing SAM predictions with existing estimates of the stellar mass function from z = 0-8, we show that the SAMs generally require strong outflows to suppress star formation in low-mass halos to match the present-day stellar mass function, as is the present common wisdom. However, all of the models considered produce predictions for the star formation rates (SFRs) and metallicities of low-mass galaxies that are inconsistent with existing data. The predictions for metallicity-stellar mass relations and their evolution clearly diverge between the models. We suggest that large differences in the metallicity relations and small differences in the stellar mass assembly histories of model galaxies stem from different assumptions for the outflow mass-loading factor produced by feedback. Importantly, while more accurate observational measurements for stellar mass, SFR and metallicity of galaxies at 1 < z < 5 will discriminate between models, the discrepancies between the constrained models and existing data of these observables have already revealed challenging problems in understanding star formation and its feedback in galaxy formation. The three sets of models are being used to construct catalogs

  18. Semi-analytic models for the CANDELS survey: comparison of predictions for intrinsic galaxy properties

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yu; Wechsler, Risa H. [Kavli Institute for Particle Astrophysics and Cosmology, Physics Department, and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Somerville, Rachel S. [Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Croton, Darren [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, P.O. Box 218, Hawthorn, VIC 3122 (Australia); Porter, Lauren; Primack, Joel; Moody, Chris [Department of Physics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); Behroozi, Peter S.; Ferguson, Henry C. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Koo, David C.; Guo, Yicheng [UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Safarzadeh, Mohammadtaher; White, Catherine E. [Department of Physics and Astronomy, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Finlator, Kristian [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark); Castellano, Marco; Sommariva, Veronica, E-mail: luyu@stanford.edu, E-mail: rwechsler@stanford.edu [INAF-Osservatorio Astronomico di Roma, via Frascati 33, I-00040 Monteporzio (Italy)

    2014-11-10

    We compare the predictions of three independently developed semi-analytic galaxy formation models (SAMs) that are being used to aid in the interpretation of results from the CANDELS survey. These models are each applied to the same set of halo merger trees extracted from the 'Bolshoi' high-resolution cosmological N-body simulation and are carefully tuned to match the local galaxy stellar mass function using the powerful method of Bayesian Inference coupled with Markov Chain Monte Carlo or by hand. The comparisons reveal that in spite of the significantly different parameterizations for star formation and feedback processes, the three models yield qualitatively similar predictions for the assembly histories of galaxy stellar mass and star formation over cosmic time. Comparing SAM predictions with existing estimates of the stellar mass function from z = 0-8, we show that the SAMs generally require strong outflows to suppress star formation in low-mass halos to match the present-day stellar mass function, as is the present common wisdom. However, all of the models considered produce predictions for the star formation rates (SFRs) and metallicities of low-mass galaxies that are inconsistent with existing data. The predictions for metallicity-stellar mass relations and their evolution clearly diverge between the models. We suggest that large differences in the metallicity relations and small differences in the stellar mass assembly histories of model galaxies stem from different assumptions for the outflow mass-loading factor produced by feedback. Importantly, while more accurate observational measurements for stellar mass, SFR and metallicity of galaxies at 1 < z < 5 will discriminate between models, the discrepancies between the constrained models and existing data of these observables have already revealed challenging problems in understanding star formation and its feedback in galaxy formation. The three sets of models are being used to construct catalogs

  19. Direct radiative forcing properties of atmospheric aerosols over semi-arid region, Anantapur in India.

    Science.gov (United States)

    Kalluri, Raja Obul Reddy; Gugamsetty, Balakrishnaiah; Kotalo, Rama Gopal; Nagireddy, Siva Kumar Reddy; Tandule, Chakradhar Rao; Thotli, Lokeswara Reddy; Rajuru Ramakrishna, Reddy; Surendranair, Suresh Babu

    2016-10-01

    This paper describes the aerosols optical, physical characteristics and the aerosol radiative forcing pertaining to semi-arid region, Anantapur for the period January 2013-December 2014. Collocated measurements of Aerosol Optical Depth (AOD) and Black Carbon mass concentration (BC) are carried out by using MICROTOPS II and Aethalometer and estimated the aerosol radiative forcing over this location. The mean values of AOD at 500nm are found to be 0.47±0.09, 0.34±0.08, 0.29±0.06 and 0.30±0.07 during summer, winter, monsoon and post-monsoon respectively. The Angstrom exponent (α380-1020) value is observed maximum in March (1.25±0.19) and which indicates the predominance of fine - mode aerosols and lowest in the month of July (0.33±0.14) and may be due to the dominance of coarse-mode aerosols. The diurnal variation of BC is exhibited two height peaks during morning 07:00-08:00 (IST) and evening 19:00-21:00 (IST) hours and one minima noticed during afternoon (13:00-16:00). The highest monthly mean BC concentration is observed in the month of January (3.4±1.2μgm(-3)) and the lowest in July (1.1±0.2μgm(-3)). The estimated Aerosol Direct Radiative Forcing (ADRF) in the atmosphere is found to be +36.8±1.7Wm(-2), +26.9±0.2Wm(-2), +18.0±0.6Wm(-2) and +18.5±3.1Wm(-2) during summer, winter, monsoon and post-monsoon seasons, respectively. Large difference between TOA and BOA forcing is observed during summer which indicate the large absorption of radiant energy (36.80Wm(-2)) which contributes more increase in atmospheric heating by ~1K/day. The BC contribution on an average is found to be 64% and is responsible for aerosol atmospheric heating. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Effects of elevated ozone on leaf {delta}{sup 13}C and leaf conductance of plant species grown in semi-natural grassland with or without irrigation

    Energy Technology Data Exchange (ETDEWEB)

    Jaeggi, M. [Agroscope FAL Reckenholz, Swiss Federal Research Station for Agroecology and Agriculture, Air Pollution/Climate Group, CH-8046 Zurich (Switzerland)]. E-mail: maya.jaeggi@psi.ch; Saurer, M. [Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Volk, M. [Agroscope FAL Reckenholz, Swiss Federal Research Station for Agroecology and Agriculture, Air Pollution/Climate Group, CH-8046 Zurich (Switzerland); Fuhrer, J. [Agroscope FAL Reckenholz, Swiss Federal Research Station for Agroecology and Agriculture, Air Pollution/Climate Group, CH-8046 Zurich (Switzerland)

    2005-03-01

    Stable carbon isotope ratios ({delta}{sup 13}C) and leaf conductance (g{sub s}) were measured (2002, 2003) in Holcus lanatus L., Plantago lanceolata L. Ranunculus friesianus (Jord.), and Trifolium pratense L. at two levels of ozone (O{sub 3}) with or without irrigation. In non-irrigated control plots, R. friesianus showed the least negative {delta}{sup 13}C, and the smallest response to the treatments. Irrigation caused more negative {delta}{sup 13}C, especially in H. lanatus. Irrespective of irrigation, O{sub 3} increased {delta}{sup 13}C in relationship to a decrease in g{sub s} in P. lanceolata and T. pratense. The strongest effect of O{sub 3} on {delta}{sup 13}C occurred in the absence of irrigation, suggesting that under field conditions lack of moisture in the top soil does not always lead to protection from O{sub 3} uptake. It is concluded that in species such as T. pratense plants can maintain stomatal O{sub 3} uptake during dry periods when roots can reach deeper soil layers where water is not limiting. - Under natural field conditions, lack of precipitation may not protect semi-natural vegetation from O{sub 3} effects on leaf gas exchange.

  1. Effects of elevated ozone on leaf δ13C and leaf conductance of plant species grown in semi-natural grassland with or without irrigation

    International Nuclear Information System (INIS)

    Jaeggi, M.; Saurer, M.; Volk, M.; Fuhrer, J.

    2005-01-01

    Stable carbon isotope ratios (δ 13 C) and leaf conductance (g s ) were measured (2002, 2003) in Holcus lanatus L., Plantago lanceolata L. Ranunculus friesianus (Jord.), and Trifolium pratense L. at two levels of ozone (O 3 ) with or without irrigation. In non-irrigated control plots, R. friesianus showed the least negative δ 13 C, and the smallest response to the treatments. Irrigation caused more negative δ 13 C, especially in H. lanatus. Irrespective of irrigation, O 3 increased δ 13 C in relationship to a decrease in g s in P. lanceolata and T. pratense. The strongest effect of O 3 on δ 13 C occurred in the absence of irrigation, suggesting that under field conditions lack of moisture in the top soil does not always lead to protection from O 3 uptake. It is concluded that in species such as T. pratense plants can maintain stomatal O 3 uptake during dry periods when roots can reach deeper soil layers where water is not limiting. - Under natural field conditions, lack of precipitation may not protect semi-natural vegetation from O 3 effects on leaf gas exchange

  2. Direct radiative forcing properties of atmospheric aerosols over semi-arid region, Anantapur in India

    Energy Technology Data Exchange (ETDEWEB)

    Kalluri, Raja Obul Reddy; Gugamsetty, Balakrishnaiah [Aerosol & Atmospheric Research Laboratory, Department of Physics, Sri Krishnadevaraya University, Anantapur 515 003, Andhra Pradesh (India); Kotalo, Rama Gopal, E-mail: krgverma@yahoo.com [Aerosol & Atmospheric Research Laboratory, Department of Physics, Sri Krishnadevaraya University, Anantapur 515 003, Andhra Pradesh (India); Nagireddy, Siva Kumar Reddy; Tandule, Chakradhar Rao; Thotli, Lokeswara Reddy [Aerosol & Atmospheric Research Laboratory, Department of Physics, Sri Krishnadevaraya University, Anantapur 515 003, Andhra Pradesh (India); Rajuru Ramakrishna, Reddy [Aerosol & Atmospheric Research Laboratory, Department of Physics, Sri Krishnadevaraya University, Anantapur 515 003, Andhra Pradesh (India); Srinivasa Ramanujan Institute of Technology, B.K. Samudram Mandal, Anantapur 515 701, Andhra Pradesh (India); Surendranair, Suresh Babu [Space Physics Laboratory, Vikram Sarabhai Space Centre, Trivandrum 695 022, Kerala (India)

    2016-10-01

    This paper describes the aerosols optical, physical characteristics and the aerosol radiative forcing pertaining to semi-arid region, Anantapur for the period January 2013-December 2014. Collocated measurements of Aerosol Optical Depth (AOD) and Black Carbon mass concentration (BC) are carried out by using MICROTOPS II and Aethalometer and estimated the aerosol radiative forcing over this location. The mean values of AOD at 500 nm are found to be 0.47 ± 0.09, 0.34 ± 0.08, 0.29 ± 0.06 and 0.30 ± 0.07 during summer, winter, monsoon and post-monsoon respectively. The Angstrom exponent (α{sub 380–1020}) value is observed maximum in March (1.25 ± 0.19) and which indicates the predominance of fine - mode aerosols and lowest in the month of July (0.33 ± 0.14) and may be due to the dominance of coarse-mode aerosols. The diurnal variation of BC is exhibited two height peaks during morning 07:00–08:00 (IST) and evening 19:00–21:00 (IST) hours and one minima noticed during afternoon (13:00–16:00). The highest monthly mean BC concentration is observed in the month of January (3.4 ± 1.2 μg m{sup −3}) and the lowest in July (1.1 ± 0.2 μg m{sup −3}). The estimated Aerosol Direct Radiative Forcing (ADRF) in the atmosphere is found to be + 36.8 ± 1.7 W m{sup −2}, + 26.9 ± 0.2 W m{sup −2}, + 18.0 ± 0.6 W m{sup −2} and + 18.5 ± 3.1 W m{sup −2} during summer, winter, monsoon and post-monsoon seasons, respectively. Large difference between TOA and BOA forcing is observed during summer which indicate the large absorption of radiant energy (36.80 W m{sup −2}) which contributes more increase in atmospheric heating by ~ 1 K/day. The BC contribution on an average is found to be 64% and is responsible for aerosol atmospheric heating. - Highlights: • The mean values of AOD{sub 500} are found to be high during summer whereas low in monsoon. • The highest values of BC are observed in January and the lowest in the month of July. • The annual mean

  3. Direct radiative forcing properties of atmospheric aerosols over semi-arid region, Anantapur in India

    International Nuclear Information System (INIS)

    Kalluri, Raja Obul Reddy; Gugamsetty, Balakrishnaiah; Kotalo, Rama Gopal; Nagireddy, Siva Kumar Reddy; Tandule, Chakradhar Rao; Thotli, Lokeswara Reddy; Rajuru Ramakrishna, Reddy; Surendranair, Suresh Babu

    2016-01-01

    This paper describes the aerosols optical, physical characteristics and the aerosol radiative forcing pertaining to semi-arid region, Anantapur for the period January 2013-December 2014. Collocated measurements of Aerosol Optical Depth (AOD) and Black Carbon mass concentration (BC) are carried out by using MICROTOPS II and Aethalometer and estimated the aerosol radiative forcing over this location. The mean values of AOD at 500 nm are found to be 0.47 ± 0.09, 0.34 ± 0.08, 0.29 ± 0.06 and 0.30 ± 0.07 during summer, winter, monsoon and post-monsoon respectively. The Angstrom exponent (α_3_8_0_–_1_0_2_0) value is observed maximum in March (1.25 ± 0.19) and which indicates the predominance of fine - mode aerosols and lowest in the month of July (0.33 ± 0.14) and may be due to the dominance of coarse-mode aerosols. The diurnal variation of BC is exhibited two height peaks during morning 07:00–08:00 (IST) and evening 19:00–21:00 (IST) hours and one minima noticed during afternoon (13:00–16:00). The highest monthly mean BC concentration is observed in the month of January (3.4 ± 1.2 μg m"−"3) and the lowest in July (1.1 ± 0.2 μg m"−"3). The estimated Aerosol Direct Radiative Forcing (ADRF) in the atmosphere is found to be + 36.8 ± 1.7 W m"−"2, + 26.9 ± 0.2 W m"−"2, + 18.0 ± 0.6 W m"−"2 and + 18.5 ± 3.1 W m"−"2 during summer, winter, monsoon and post-monsoon seasons, respectively. Large difference between TOA and BOA forcing is observed during summer which indicate the large absorption of radiant energy (36.80 W m"−"2) which contributes more increase in atmospheric heating by ~ 1 K/day. The BC contribution on an average is found to be 64% and is responsible for aerosol atmospheric heating. - Highlights: • The mean values of AOD_5_0_0 are found to be high during summer whereas low in monsoon. • The highest values of BC are observed in January and the lowest in the month of July. • The annual mean atmospheric forcing is found to be

  4. Physical and chemical properties of soils under some wild Pistachio (Pistacia atlantica Desf) canopies in a semi-arid ecosystem, southwestern Iran.

    Science.gov (United States)

    Owliaie, Hamidreza

    2010-05-01

    Pistacia atlantica Desf. is one of the most important wild species in Zagros forests which is of high economical and environmental value. Sustainability of these forests primarily depends on soil quality and water availability. Study the relationships between trees and soil is one of the basic factors in management and planning of forests. Hence, this study was undertaken with the objective of assessing the effect of tree species on soil physical and chemical properties in a semi-arid region (Kohgilouye Province) in the southwestern part of Iran. The experimental design was a factorial 4×2 (4 depths and 2 distances) in a randomized complete block design with six replications. Soil samples (0-20, 20-40, 40-60 and 60-80 cm depth) were taken from beneath the tree crowns and adjacent open areas. Soil samples were analyzed for physical and chemical properties. The results showed that wild pistachio canopy increased mostly organic carbon, hydraulic conductivity, total N, SP, available K+, P (olsen), EC, EDTA extractable Fe2+ and Mn2+, while bulk density, CCE and DTPA extractable Cu2+ were decreased. Pistachio canopy had no significant effect on soil texture, Zn2+ and pH.

  5. Tunable electronic transport properties of silicon-fullerene-linked nanowires: Semiconductor, conducting wire, and tunnel diode

    OpenAIRE

    Nishio, Kengo; Ozaki, Taisuke; Morishita, Tetsuya; Mikami, Masuhiro

    2010-01-01

    We explore the possibility of controllable tuning of the electronic transport properties of silicon-fullerene-linked nanowires by encapsulating guest atoms into their cages. Our first-principles calculations demonstrate that the guest-free nanowires are semiconductors, and do not conduct electricity. The iodine or sodium doping improves the transport properties, and makes the nanowires metallic. In the junctions of I-doped and Na-doped NWs, the current travels through the boundary by quantum ...

  6. Optical and electrical properties of Cu-based all oxide semi-transparent photodetector

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hong-Sik; Patel, Malkeshkumar; Yadav, Pankaj; Kim, Joondong, E-mail: joonkim@inu.ac.kr, E-mail: dwkim@ewha.ac.kr [Photoelectric and Energy Device Application Lab (PEDAL) and Department of Electrical Engineering, Incheon National University, 119 Academy Rd., Yeonsu, Incheon 406772 (Korea, Republic of); Sohn, Ahrum; Kim, Dong-Wook, E-mail: joonkim@inu.ac.kr, E-mail: dwkim@ewha.ac.kr [Department of Physics, Ewha Womans University, Seoul 120750 (Korea, Republic of)

    2016-09-05

    Zero-bias operating Cu oxide-based photodetector was achieved by using large-scale available sputtering method. Cu oxide (Cu{sub 2}O or CuO) was used as p-type transparent layer to form a heterojunction by contacting n-type ZnO layer. All metal-oxide materials were employed to realize transparent device at room temperature and showed a high transparency (>75% at 600 nm) with excellent photoresponses. The structural, morphological, optical, and electrical properties of Cu oxides of CuO and Cu{sub 2}O are evaluated in depth by UV-visible spectrometer, X-ray diffraction, scanning electron microscopy, atomic force microscopy, Kelvin probe force microscopy, and Hall measurements. We may suggest a route of high-functional Cu oxide-based photoelectric devices for the applications in flexible and transparent electronics.

  7. Mechanical and magnetic properties of semi-Heusler/light-metal composites consolidated by spark plasma sintering

    Czech Academy of Sciences Publication Activity Database

    Koller, M.; Chráska, Tomáš; Cinert, Jakub; Heczko, Oleg; Kopeček, Jaromír; Landa, Michal; Mušálek, Radek; Rameš, Michal; Seiner, Hanuš; Stráský, J.; Janeček, M.

    2017-01-01

    Roč. 126, July (2017), s. 351-357 ISSN 0264-1275 R&D Projects: GA ČR GB14-36566G Institutional support: RVO:61389021 ; RVO:68378271 ; RVO:61388998 Keywords : Metal–metal composites * Spark plasma sintering * Light metals * Ferromagnetic alloys * Mechanical properties Subject RIV: JI - Composite Materials; JI - Composite Materials (FZU-D); JI - Composite Materials (UT-L) OBOR OECD: Composites (including laminates, reinforced plastics, cermets, combined natural and synthetic fibre fabrics; Composites (including laminates, reinforced plastics, cermets, combined natural and synthetic fibre fabrics (FZU-D); Composites (including laminates, reinforced plastics, cermets, combined natural and synthetic fibre fabrics (UT-L) Impact factor: 4.364, year: 2016 https://www.sciencedirect.com/science/ article /pii/S0264127517303842?via%3Dih

  8. Magnetorheological technology for fabricating tunable solid electrolyte with enhanced conductivity and mechanical property

    Science.gov (United States)

    Peng, Gangrou; Ge, Yu; Ding, Jie; Wang, Caiyun; Wallace, Gordon G.; Li, Weihua

    2018-03-01

    Ionogels are a new class of hybrid materials where ionic liquids are immobilized by macromolecular support. The excessive amount of crosslinking polymer enhances the mechanical strength but compromises the conductivity. Here, we report an elastomeric magnetorheological (MR) ionogel with an enhanced conductivity and mechanical strength as well. Following the application of magnetic nanoparticles into an ionic liquid containing minimum cross-linking agent, the formation, thus physical properties, of MR ionogels are co-controlled by simultaneously applied UV light and external magnetic field. The application of MR ionogels as solid electrolytes in supercapacitors is also demonstrated to study electrochemical performance. This work opens a new avenue to synthesize robust ionogels with the desired conductivity and controllable mechanical properties for soft flexible electronic devices. Besides, as a new class of conductive MR elastomers, the proposed MR ionogel also possesses the potential for engineering applications, such as sensors and actuators.

  9. The influence of increased membrane conductance on response properties of spinal motoneurons

    DEFF Research Database (Denmark)

    Grigonis, Ramunas; Guzulaitis, Robertas; Buisas, Rokas

    2016-01-01

    During functional spinal neural network activity motoneurons receive massive synaptic excitation and inhibition, and their membrane conductance increases considerably – they are switched to a high-conductance state. High-conductance states can substantially alter response properties of motoneurons....... In the present study we investigated how an increase in membrane conductance affects spike frequency adaptation, the gain (i.e., the slope of the frequency-current relationship) and the threshold for action potential generation. We used intracellular recordings from adult turtle motoneurons in spinal cord slices....... Membrane conductance was increased pharmacologically by extracellular application of the GABAA receptor agonist muscimol. Our findings suggest that an increase in membrane conductance of about 40–50% increases the magnitude of spike frequency adaptation, but does not change the threshold for action...

  10. Effect of Graphene Nanoplatelets addition on mechanical properties of pure aluminum using a semi-powder method

    Directory of Open Access Journals (Sweden)

    Muhammad Rashad

    2014-04-01

    Full Text Available In recent years, graphene has attracted considerable research interest in all fields of science due to its unique properties. Its excellent mechanical properties lead it to be used in nano-composites for strength enhancement. This paper reports an Aluminum–Graphene Nanoplatelets (Al/GNPs composite using a semi-powder method followed by hot extrusion. The effect of GNP nano-particle integration on tensile, compressive and hardness response of Al is investigated in this paper. It is demonstrated that 0.3 wt% Graphene Nanoplatelets distributed homogeneously in the matrix aluminum act as an effective reinforcing filler to prevent deformation. Compared to monolithic aluminum (in tension, Al–0.3 wt% GNPs composite exhibited higher 0.2% yield strength (+14.7%, ultimate tensile strength (+11.1% and lower failure strain (−40.6%. Surprisingly, compared to monolithic Al (in compression, Al–0.3 wt% GNPs composite exhibited same 0.2% compressive yield strength and lower ultimate compression strength (−7.8%, and lower failure strain (−20.2%. The Al–0.3 wt% GNPs composite exhibited higher Vickers hardness compared to monolithic aluminum (+11.8%. Scanning electron microscopy (SEM, Energy-Dispersive X-ray Spectroscopy (EDS and X-ray diffraction (XRD were used to investigate the surface morphology, elemental percentage composition, and phase analysis, respectively.

  11. EXPRESIÓN SEMI-ANALÍTICA PARA EL CÁLCULO DE MATRICES DE CONDUCTIVIDAD DE ELEMENTOS FINITOS EN PROBLEMAS DE CONDUCCIÓN DE CALOR //\tA SEMI-ANALYTICAL EXPRESSION FOR CALCULATING FINITE ELEMENT CONDUCTIVITY MATRICES IN HEAT CONDUCTION PROBLEMS

    Directory of Open Access Journals (Sweden)

    Hector Godoy

    2012-12-01

    Full Text Available The heat transfer equation by conduction is not more than a mathematical expression of the energy conservation law for a given solid. Solving the equation which model this problem is generally very dificult or impossible in an analytical way, so it is necessary to make a discrete approximation of the continuous problem. In this paper, we present a methodology applied to the quadrilateral finite elements in problems of heat transfer by conduction, where the components of the thermal conductivity matrix are obtained by a semi-analytical expression and simple algebraic manipulations. This technique has been used successfully in stiness arrays' integrations of bidimensional and tridimensional finite elements, reporting substantial improvements of CPU times compared with the Gaussian integration. // RESUMEN: La ecuación para la transferencia de calor por conducción no es más que una expresión matemática de la ley de conservación de la energía para un sólido dado. La resolución de la ecuación que modela este problema generalmente es muy difícil o imposible de obtener de forma analítica, por ello es necesario efectuar una aproximación discreta del problema continuo. En este trabajo, se presenta una metodología aplicada a elementos finitos cuadriláteros en problemas de transferencia de calor por conducción, donde las componentes de la matriz de conductividad térmica son obtenidas mediante una expresión semi-analítica y manipulaciones algebraicas sencillas. Esta técnica ha sido utilizada exitosamente en integraciones de matrices de rigidez de elementos finitos bidimensionales y tridimensionales,reportando mejoras sustanciales de tiempos de CPU en comparación con la integración Gaussiana.

  12. Nanoscale electrical property studies of individual GeSi quantum rings by conductive scanning probe microscopy.

    Science.gov (United States)

    Lv, Yi; Cui, Jian; Jiang, Zuimin M; Yang, Xinju

    2012-11-29

    The nanoscale electrical properties of individual self-assembled GeSi quantum rings (QRs) were studied by scanning probe microscopy-based techniques. The surface potential distributions of individual GeSi QRs are obtained by scanning Kelvin microscopy (SKM). Ring-shaped work function distributions are observed, presenting that the QRs' rim has a larger work function than the QRs' central hole. By combining the SKM results with those obtained by conductive atomic force microscopy and scanning capacitance microscopy, the correlations between the surface potential, conductance, and carrier density distributions are revealed, and a possible interpretation for the QRs' conductance distributions is suggested.

  13. Electrical Properties of PPy-Coated Conductive Fabrics for Human Joint Motion Monitoring

    Directory of Open Access Journals (Sweden)

    Jiyong Hu

    2016-03-01

    Full Text Available Body motion signals indicate several pathological features of the human body, and a wearable human motion monitoring system can respond to human joint motion signal in real time, thereby enabling the prevention and treatment of some diseases. Because conductive fabrics can be well integrated with the garment, they are ideal as a sensing element of wearable human motion monitoring systems. This study prepared polypyrrole conductive fabric by in situ polymerization, and the anisotropic property of the conductive fabric resistance, resistance–strain relationship, and the relationship between resistance and the human knee and elbow movements are discussed preliminarily.

  14. Phonon scattering and thermal conductance properties in two coupled graphene nanoribbons modulated with bridge atoms

    International Nuclear Information System (INIS)

    Tan, Shi-Hua; Tang, Li-Ming; Chen, Ke-Qiu

    2014-01-01

    The phonon scattering and thermal conductance properties have been studied in two coupled graphene nanoribbons connected by different bridge atoms by using density functional theory in combination with non-equilibrium Green's function approach. The results show that a wide range of thermal conductance tuning can be realized by changing the chemical bond strength and atom mass of the bridge atoms. It is found that the chemical bond strength (bridge atom mass) plays the main role in phonon scattering at low (high) temperature. A simple equation is presented to describe the relationship among the thermal conductance, bridge atom, and temperature.

  15. Manipulating dispersion and distribution of graphene in PLA through Novel Interface Engineering for improved conductive properties

    Science.gov (United States)

    This study aimed to enhance the conductive properties of PLA nanocomposite by controlling the dispersion and distribution of graphene within the minor phase of the polymer blend. Functionalized graphene (f-GO) was achieved by reacting graphene oxide (GO) with various silanes under the aid of an ioni...

  16. Inversion of soil electrical conductivity data to estimate layered soil properties

    Science.gov (United States)

    CBulk apparent soil electrical conductivity (ECa) sensors respond to multiple soil properties, including clay content, water content, and salt content (i.e., salinity). They provide a single sensor value for an entire soil profile down to a sensor-dependent measurement depth, weighted by a nonlinear...

  17. A green and facile hydrothermal approach for the synthesis of high-quality semi-conducting Sb{sub 2}S{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Meng; Gong, Yongshuai; Li, Zhilin; Dou, Meiling, E-mail: douml@mail.buct.edu.cn; Wang, Feng, E-mail: wangf@mail.buct.edu.cn

    2016-11-30

    Highlights: • A green and facile hydrothermal approach for Sb{sub 2}S{sub 3} films was developed. • The film possessed a relatively ideal S/Sb atomic ratio and a compact surface. • The grain size of Sb{sub 2}S{sub 3} was increased by high temperature annealing. • The film annealed at 450 °C showed the improved optical and electrical performance. - Abstract: High-quality semi-conducting antimony sulfide (Sb{sub 2}S{sub 3}) thin films were directly deposited on the indium tin oxide (ITO) substrates by a green and facile one-step approach based on a hydrothermal reaction and post-annealing process without any assistance of complexing agents. The obtained Sb{sub 2}S{sub 3} films possessed a relatively ideal S/Sb atomic ratio and a compact and continuous surface as the grain size of Sb{sub 2}S{sub 3} was increased by high temperature annealing. The Sb{sub 2}S{sub 3} film annealed at 450 °C exhibited the improved optical and electrical performances, with a narrow band gap of 1.63 eV, an electrical resistivity of 1.3 × 10{sup 4} Ω cm, a carrier concentration of 7.3 × 10{sup 13} cm{sup −3} and a carrier mobility of 6.4 cm{sup 2} V{sup −1} s{sup −1}. This environmentally friendly synthetic route is promising for the preparation of high-quality Sb{sub 2}S{sub 3} films to be used as absorber layer materials for high-performance solar cells.

  18. Estimating saturated hydraulic conductivity and air permeability from soil physical properties using state-space analysis

    DEFF Research Database (Denmark)

    Poulsen, Tjalfe; Møldrup, Per; Nielsen, Don

    2003-01-01

    and gaseous chemicals in the vadose zone. In this study, three modeling approaches were used to identify the dependence of saturated hydraulic conductivity (K-S) and air permeability at -100 cm H2O soil-water potential (k(a100)) on soil physical properties in undisturbed soil: (i) Multiple regression, (ii......) ARIMA (autoregressive integrated moving average) modeling, and (iii) State-space modeling. In addition to actual soil property values, ARIMA and state-space models account for effects of spatial correlation in soil properties. Measured data along two 70-m-long transects at a 20-year old constructed......Estimates of soil hydraulic conductivity (K) and air permeability (k(a)) at given soil-water potentials are often used as reference points in constitutive models for K and k(a) as functions of moisture content and are, therefore, a prerequisite for predicting migration of water, air, and dissolved...

  19. Interaction forces and conduction properties between multi wall carbon nanotube tips and Au(1 1 1)

    Energy Technology Data Exchange (ETDEWEB)

    Luna, M.; Pablo, P.J. de; Colchero, J.; Gomez-Herrero, J.; Baro, A.M.; Tokumoto, H.; Jarvis, S.P

    2003-07-15

    We have studied the interaction forces and electrical conduction properties arising between multiwall carbon nanotube tips and the Au(1 1 1) surface in air, by means of amplitude modulation scanning force microscopy, also called intermittent contact. We have centered our work on tips with metallic electronic structure and for the specific parameters used we have found a preliminary interaction range where there is no contact between tip and surface. Stable imaging in this non-contact range is possible with multiwall carbon nanotube tips. These tips have also been used to obtain simultaneous topographic and current maps of the surface. They show excellent properties as tips due to their high aspect ratio and durability, as a result of their elastic and non-reactive properties. Correspondingly, multiwall carbon nanotube tips allow high resolution local analysis of electrical conductivity on a nanometer scale.

  20. Fabrication and simulation of semi-transparent and flexible PMMA/ATO conductive nanocomposites obtained by compression molding at different temperatures and pressures

    Directory of Open Access Journals (Sweden)

    Youngho Jin

    2017-05-01

    Full Text Available This paper investigated the effect of temperature and pressure on the microstructure and electrical behavior of compression molded and mechanically blended polymer composites. Poly (methyl methacrylate (PMMA and antimony tin oxide (ATO were used as the matrix and conductive filler respectively and the composition was varied from 0 to 1.75 ATO vol %. Mixtures of the two precursor materials were compression molded at temperatures ranging from 150 to 190 °C and pressures ranging from 12 to 50 MPa. It was found that a segregated network microstructure was formed in all cases but that the distribution of the conductive ATO fillers varied as a function of the compression molding temperature and pressure used. The thickness of the specimens, determined by the amount of precursor materials and pressure used during compression molding, was also found to affect the resulting microstructure and concomitant properties. The electrical conductivity of these polymer matrix composites can be increased by up to 2 orders of magnitude by decreasing the processing temperature, while maintaining the processing pressure and the filler concentration constant. On the other hand, the flexibility of PMCs can be improved by increasing the processing temperature. For the compositions evaluated, the maximum electrical conductivity obtained was 5 x 10-3 S/m (about three orders of magnitude lower than the conductivity of the filler. Finite element simulations were used to model this microstructure-driven phase segregated percolation behavior. COMSOL Multiphysics® was used to calculate the electric potential and current density distribution in a 3D geometry. There was good agreement between the experimental and simulation results.

  1. Development of Semi-Stochastic Algorithm for Optimizing Alloy Composition of High-Temperature Austenitic Stainless Steels (H-Series) for Desired Mechanical and Corrosion Properties.

    Energy Technology Data Exchange (ETDEWEB)

    Dulikravich, George S.; Sikka, Vinod K.; Muralidharan, G.

    2006-06-01

    The goal of this project was to adapt and use an advanced semi-stochastic algorithm for constrained multiobjective optimization and combine it with experimental testing and verification to determine optimum concentrations of alloying elements in heat-resistant and corrosion-resistant H-series stainless steel alloys that will simultaneously maximize a number of alloy's mechanical and corrosion properties.

  2. Detection and differentiation of pollution in urban surface soils using magnetic properties in arid and semi-arid regions of northwestern China.

    Science.gov (United States)

    Wang, Bo; Xia, Dunsheng; Yu, Ye; Jia, Jia; Xu, Shujing

    2014-01-01

    Increasing urbanization and industrialization over the world has caused many social and environmental problems, one of which drawing particular concern is the soil pollution and its ecological degradation. In this study, the efficiency of magnetic methods for detecting and discriminating contaminates in the arid and semi-arid regions of northwestern China was investigated. Topsoil samples from six typical cities (i.e. Karamay, Urumqi, Lanzhou, Yinchuan, Shizuishan and Wuhai) were collected and a systematic analysis of their magnetic properties was conducted. Results indicate that the topsoil samples from the six cities were all dominated by coarse low-coercivity magnetite. In addition, the average magnetite contents in the soils from Urumqi and Lanzhou were shown to be much higher than those from Karamay, Yinchuan, Shizuishan and Wuhai, and they also have relatively higher χlf and χfd% when compared with cities in eastern China. Moreover, specific and distinctive soil pollution signals were identified at each sampling site using the combined various magnetic data, reflecting distinct sources. Industrial and traffic-derived pollution was dominant in Urumqi and Lanzhou, in Yinchuan industrial progress was observed to be important with some places affected by vehicle emission, while Karamay, Shizuishan and Wuhai were relatively clean. The magnetic properties of these latter three cities are significantly affected by both anthropogenic pollution and local parent materials from the nearby Gobi desert. The differences in magnetic properties of topsoil samples affected by mixed industrial and simplex traffic emissions are not obvious, but significant differences exist in samples affected by simplex industrial/vehicle emissions and domestic pollution. The combined magnetic analyses thus provide a sensitive and powerful tool for classifying samples according to likely sources, and may even provide a valuable diagnostic tool for discriminating among different cities

  3. The effect of edge and impurities sites properties on their localized states in semi-infinite zigzag edged 2D honeycomb graphene sheet

    OpenAIRE

    Ahmed, Maher

    2011-01-01

    In this work, the tridiagonal method is used to distinguish between edges modes and area modes to study the edge sites properties effect on edge localized states of semi-infinite zigzag 2D honeycomb graphene sheet. The results show a realistic behavior for the dependance of edge localized states of zigzag graphene on the edge sites properties which explaining the experimental results of measured local density of states at the edge of graphene, while at the same time removing the inconsistence...

  4. Site properties for Crimean juniper (Juniperus excelsa) in semi-natural forests of south western Anatolia, Turkey.

    Science.gov (United States)

    Ozkan, Kürsad; Gulsoy, Serkan; Aerts, Raf; Muys, Bart

    2010-01-01

    We explored the semi-natural forests in south western Anatolia along a gradient between Mediterranean and continental climates to determine the site requirements of Juniperus excelsa in Turkey. We hypothesized that environmental variables and indicator species can be used to predict differences in occurrence and cover of J. excelsa and can therefore support decision making in reforestation management planning. Plant species composition and environmental variables were assessed in 153 plots. Association between J. excelsa and other plant species and environmental variables were analyzed using Fisher exact probability tests and stepwise discriminant analysis. High altitude (> 1000 m) as a proxy for an Oromediterranean climate, and high surface stoniness as a proxy for low competition by other tree species, are positive site properties for J. excelsa. The tree species avoids Eumediterranean and Supramediterranean plant communities. Twelve plant species, including the herbs Dianthus zonatus, Ajuga chamaepitys and Paronchia carica and the shrub Cotoneaster nummularia may be used as site indicators for J. excelsa restoration. Platanus orientalis, with similar site requirements but at present negatively associated to J. excelsa due to competitive effects, may be considered an additional indicator if stand conversion (harvesting and replacing P. orientalis) is part of the management plan.

  5. Molecular models of zinc phthalocyanines: semi-empirical molecular orbital computations and physicochemical properties studied by molecular mechanics simulations

    International Nuclear Information System (INIS)

    Gantchev, Tsvetan G.; van Lier, Johan E.; Hunting, Darel J.

    2005-01-01

    To build 3D-molecular models of Zinc-phthalocyanines (ZnPc) and to study their diverse chemical and photosensitization properties, we performed quantum mechanical molecular orbital (MO) semi-empirical (AM1) computations of the ground, excited singlet and triplet states as well as free radical (ionic) species. RHF and UHF (open shell) geometry optimizations led to near-perfect symmetrical ZnPc. Predicted ionization potentials (IP), electron affinities (EA) and lowest electronic transitions of ZnPc are in good agreement with the published experimental and theoretical data. The computation-derived D 4h /D 2h -symmetry 3D-structures of ground and excited states and free radicals of ZnPc, together with the frontier orbital energies and Mulliken electron population analysis enabled us to build robust molecular models. These models were used to predict important chemical-reactivity entities such as global electronegativity (χ), hardness (η) and local softness based on Fukui-functions analysis. Examples of molecular mechanics (MM) applications of the 3D-molecular models are presented as approaches to evaluate solvation free energy (ΔG 0 ) solv and to estimate ground- and excited- state oxidation/reduction potentials as well as intermolecular interactions and stability of ground and excited state dimers (exciplexes) and radical ion-pairs

  6. Reflecting and Polarizing Properties of Conductive Fabrics in Ultra-High Frequency Range

    Directory of Open Access Journals (Sweden)

    Oleg Kiprijanovič

    2015-09-01

    Full Text Available The system based on ultra-wide band (UWB signals was employed for qualitative estimation of attenuating, reflecting and polarizing properties of conductive fabrics, capable to prevent local static charge accumulation. Pulsed excitation of triangle monopole antenna of 6.5 cm height by rectangular electric pulses induced radiation of UWB signals with spectral density of power having maximum in ultra-high frequency (UHF range. The same antenna was used for the radiated signal receiving. Filters and amplifiers of different passband were employed to divide UHF range into subranges of 0.3-0.55 GHz, 0.55-1 GHz, 1-2 GHz and 2-4 GHz bands. The free space method, when conductive fabric samples of 50x50 cm2 were placed between transmitting and receiving antennas, was used to imitate a practical application. Received wideband signals corresponding to the defined range were detected by unbiased detectors. The fabrics made of two types of warps, containing different threads with conductive yarns, were investigated. It was estimated attenuation and reflective properties of the fabrics when electric field is collinear or perpendicular to thread direction. In the UHF range it was revealed good reflecting properties of the fabrics containing metallic component in the threads. The system has advantages but not without a certain shortcoming. Adapting it for specific tasks should lead to more effective usage, including yet unused properties of the UWB signals.

  7. Prediction of Geomechanical Properties from Thermal Conductivity of Low-Permeable Reservoirs

    Science.gov (United States)

    Chekhonin, Evgeny; Popov, Evgeny; Popov, Yury; Spasennykh, Mikhail; Ovcharenko, Yury; Zhukov, Vladislav; Martemyanov, Andrey

    2016-04-01

    A key to assessing a sedimentary basin's hydrocarbon prospect is correct reconstruction of thermal and structural evolution. It is impossible without adequate theory and reliable input data including among other factors thermal and geomechanical rock properties. Both these factors are also important in geothermal reservoirs evaluation and carbon sequestration problem. Geomechanical parameters are usually estimated from sonic logging and rare laboratory measurements, but sometimes it is not possible technically (low quality of the acoustic signal, inappropriate borehole and mud conditions, low core quality). No wonder that there are attempts to correlate the thermal and geomechanical properties of rock, but no one before did it with large amount of high quality thermal conductivity data. Coupling results of sonic logging and non-destructive non-contact thermal core logging opens wide perspectives for studying a relationship between the thermal and geomechanical properties. More than 150 m of full size cores have been measured at core storage with optical scanning technique. Along with results of sonic logging performed with Sonic Scanner in different wells drilled in low permeable formations in West Siberia (Russia) it provided us with unique data set. It was established a strong correlation between components of thermal conductivity (measured perpendicular and parallel to bedding) and compressional and shear acoustic velocities in Bazhen formation. As a result, prediction of geomechanical properties via thermal conductivity data becomes possible, corresponding results was demonstrated. The work was supported by the Russian Ministry of Education and Science, project No. RFMEFI58114X0008.

  8. Semi-Markov processes

    CERN Document Server

    Grabski

    2014-01-01

    Semi-Markov Processes: Applications in System Reliability and Maintenance is a modern view of discrete state space and continuous time semi-Markov processes and their applications in reliability and maintenance. The book explains how to construct semi-Markov models and discusses the different reliability parameters and characteristics that can be obtained from those models. The book is a useful resource for mathematicians, engineering practitioners, and PhD and MSc students who want to understand the basic concepts and results of semi-Markov process theory. Clearly defines the properties and

  9. Defined-size DNA triple crossover construct for molecular electronics: modification, positioning and conductance properties.

    Science.gov (United States)

    Linko, Veikko; Leppiniemi, Jenni; Paasonen, Seppo-Tapio; Hytönen, Vesa P; Toppari, J Jussi

    2011-07-08

    We present a novel, defined-size, small and rigid DNA template, a so-called B-A-B complex, based on DNA triple crossover motifs (TX tiles), which can be utilized in molecular scale patterning for nanoelectronics, plasmonics and sensing applications. The feasibility of the designed construct is demonstrated by functionalizing the TX tiles with one biotin-triethylene glycol (TEG) and efficiently decorating them with streptavidin, and furthermore by positioning and anchoring single thiol-modified B-A-B complexes to certain locations on a chip via dielectrophoretic trapping. Finally, we characterize the conductance properties of the non-functionalized construct, first by measuring DC conductivity and second by utilizing AC impedance spectroscopy in order to describe the conductivity mechanism of a single B-A-B complex using a detailed equivalent circuit model. This analysis also reveals further information about the conductivity of DNA structures in general.

  10. Light brick mortar with low thermal conductivity for stressed brickwork. Types, properties, limits of application

    Energy Technology Data Exchange (ETDEWEB)

    Plank, A [Bundesanstalt fuer Materialpruefung, Berlin (Germany, F.R.)

    1980-03-01

    Between 40 and 50% of the total energy consumption are used for space heating. 40% of the total heat loss dissipate through external walls due to transmission. The heat insulation properties of a brickwork is decisively determined by the mortar joints. Using light brick mortars with low thermal conductivity an improvement of the total thermal insulation of nearly 20% can be reached in most of the cases. The mechanical properties of these mortars that differ from the common mortars decisively reduce the application of the light brick mortar in brick working and require special measures for stability which are described in detail.

  11. Consistency in thermophysical properties: enthalpy, heat capacity, thermal conductivity and thermal diffusivity of solid UO2

    International Nuclear Information System (INIS)

    Fink, J.K.; Chasanov, M.G.; Leibowitz, L.

    Equations have been derived for the enthalpy, heat capacity, thermal conductivity, and thermal diffusivity of UO 2 . In selection of these equations, we considered the traditional criterion of lowest relative standard deviation between experimental data and the function chosen to fit these data as well as consistency between the thermophysical properties. In the latter case, we considered consistency in (1) thermodynamic relations among properties, (2) the choice of physical phenomena on which to base the theoretical formulation of the equations, and (3) the existence and temperature of phase transitions

  12. Thermal conductivity and phase-change properties of aqueous alumina nanofluid

    International Nuclear Information System (INIS)

    Teng, Tun-Ping

    2013-01-01

    Highlights: ► The alumina nanofluid with chitosan was produced by two-step synthesis method. ► The k and phase-change properties of alumina nanofluid were examined. ► Adding Al 2 O 3 nanoparticles into water indeed improves the k. ► Adding the chitosan decreases the thermal conductivity of alumina nanofluid. ► The T cp and h c are 53.4% and 97.8% of those in DW with the optimal combination. - Abstract: This study uses thermal conductivity and differential scanning calorimeter experiments to explore the thermal conductivity and phase-change properties of alumina (Al 2 O 3 )–water nanofluid produced using a two-step synthesis method. Deionized water (DW) is used as a control group, and the Al 2 O 3 –water nanofluid uses chitosan as a dispersant. Nanoparticle morphology and materials were confirmed using transmission electron microscopy (TEM) and X-ray diffraction (XRD), respectively. The results show that adding Al 2 O 3 nanoparticles to DW improves DW thermal conductivity, but adding chitosan reduces the thermal conductivity of Al 2 O 3 –water nanofluid. Adding the nanoparticles to DW affects the phase-change peak temperature and phase change heat. The optimal combination is 0.1 wt.% chitosan and 0.5 wt.% Al 2 O 3 nanoparticles; the charging phase-change peak temperature and latent heat are 53.4% and 97.8% of those in DW, respectively

  13. Thermal conduction properties of Mo/Si multilayers for extreme ultraviolet optics

    Science.gov (United States)

    Bozorg-Grayeli, Elah; Li, Zijian; Asheghi, Mehdi; Delgado, Gil; Pokrovsky, Alexander; Panzer, Matthew; Wack, Daniel; Goodson, Kenneth E.

    2012-10-01

    Extreme ultraviolet (EUV) lithography requires nanostructured optical components, whose reliability can be influenced by radiation absorption and thermal conduction. Thermal conduction analysis is complicated by sub-continuum electron and phonon transport and the lack of thermal property data. This paper measures and interprets thermal property data, and their evolution due to heating exposure, for Mo/Si EUV mirrors with 6.9 nm period and Mo/Si thickness ratios of 0.4/0.6 and 0.6/0.4. We use time-domain thermoreflectance and the 3ω method to estimate the thermal resistance between the Ru capping layer and the Mo/Si multilayers (RRu-Mo/Si = 1.5 m2 K GW-1), as well as the out-of-plane thermal conductivity (kMo/Si 1.1 W m-1 K-1) and thermal anisotropy (η = 13). This work also reports the impact of annealing on thermal conduction in a co-deposited MoSi2 layer, increasing the thermal conductivity from 1.7 W m-1 K-1 in the amorphous phase to 2.8 W m-1 K-1 in the crystalline phase.

  14. Crystallite Size Effect on Thermal Conductive Properties of Nonwoven Nanocellulose Sheets.

    Science.gov (United States)

    Uetani, Kojiro; Okada, Takumi; Oyama, Hideko T

    2015-07-13

    The thermal conductive properties, including the thermal diffusivity and resultant thermal conductivity, of nonwoven nanocellulose sheets were investigated by separately measuring the thermal diffusivity of the sheets in the in-plane and thickness directions with a periodic heating method. The cross-sectional area (or width) of the cellulose crystallites was the main determinant of the thermal conductive properties. Thus, the results strongly indicate that there is a crystallite size effect on phonon conduction within the nanocellulose sheets. The results also indicated that there is a large interfacial thermal resistance between the nanocellulose surfaces. The phonon propagation velocity (i.e., the sound velocity) within the nanocellulose sheets was estimated to be ∼800 m/s based on the relationship between the thermal diffusivities and crystallite widths. The resulting in-plane thermal conductivity of the tunicate nanocellulose sheet was calculated to be ∼2.5 W/mK, markedly higher than other plastic films available for flexible electronic devices.

  15. The effect of replaced recycled glass on thermal conductivity and compression properties of cement

    Science.gov (United States)

    khalil, A. S.; Mahmoud, M. A.; AL-Hathal, A.; Jawad, M. K.; Mozahim, B. M.

    2018-05-01

    This study deal with recycling of waste colorless glass bottles which are prepared as a powder and use them as an alternative for cement to save the environment from west and reduce some of cement(ceramic) damage and interactions with conserving physical properties of block concrete. Different weight percentage (0%, 2%, 4%, 5%, 6%, 8%, 10%, 15%, 20% and 25%) of recycled glass bottle were use in this research to be replaced by a certain percentages of cement. Thermal conductivity was studied for prepared samples. Results show that the thermal conductivity decrease with the increase of weight percentage of glass powder comparing with the stander sample.

  16. Membrane potential and response properties of populations of cortical neurons in the high conductance state

    International Nuclear Information System (INIS)

    Moreno-Bote, Ruben; Parga, Nestor

    2005-01-01

    Because of intense synaptic activity, cortical neurons are in a high conductance state. We show that this state has important consequences on the properties of a population of independent model neurons with conductance-based synapses. Using an adiabaticlike approximation we study both the membrane potential and the firing probability distributions across the population. We find that the latter is bimodal in such a way that at any particular moment some neurons are inactive while others are active. The population rate and the response variability are also characterized

  17. Photo control of transport properties in a disordered wire: Average conductance, conductance statistics, and time-reversal symmetry

    International Nuclear Information System (INIS)

    Kitagawa, Takuya; Oka, Takashi; Demler, Eugene

    2012-01-01

    In this paper, we study the full conductance statistics of a disordered 1D wire under the application of light. We develop the transfer matrix method for periodically driven systems to analyze the conductance of a large system with small frequency of light, where coherent photon absorptions play an important role to determine not only the average but also the shape of conductance distributions. The average conductance under the application of light results from the competition between dynamic localization and effective dimension increase, and shows non-monotonic behavior as a function of driving amplitude. On the other hand, the shape of conductance distribution displays a crossover phenomena in the intermediate disorder strength; the application of light dramatically changes the distribution from log-normal to normal distributions. Furthermore, we propose that conductance of disordered systems can be controlled by engineering the shape, frequency and amplitude of light. Change of the shape of driving field controls the time-reversals symmetry and the disordered system shows analogous behavior as negative magneto-resistance known in static weak localization. A small change of frequency and amplitude of light leads to a large change of conductance, displaying giant opto-response. Our work advances the perspective to control the mean as well as the full conductance statistics by coherently driving disordered systems. - Highlights: ► We study conductance of disordered systems under the application of light. ► Full conductance distributions are obtained. ► A transfer matrix method is developed for driven systems. ► Conductances are dramatically modified upon the application of light. ► Time-reversal symmetry can also be controlled by light application.

  18. Correlation of Electrical and Swelling Properties with Nano Free Volume Structure of Conductive Silicone Rubber Composites

    International Nuclear Information System (INIS)

    Abd-El Salam, M.H.; El-Gamal, S.; Abd El-Maqsoud, D.M.; Mohsen, M.

    2013-01-01

    The present study focuses on finding a correlation between the positron annihilation parameters in silicone rubber based on Poly dimethyl siloxane (PDMS) composites loaded with different conductive fillers and their swelling and electrical properties. Four types of conductive fillers have been used in this study: carbon black, graphite, copper, and nickel powders. The maximum degree of swelling Q m %, the penetration rate, P, as well as the diffusion coefficient, D, decrease with increasing the filler content due to the reduction of the size of free volume, as observed through a decrease of the probability of ortho-positronium (o-Ps) formation I 3 and the o-Ps lifetime Τ 3 , representing the size of free volume measured by the positron annihilation lifetime technique (PAL). The electrical conductivity ln (Σ) is positively correlated with the probability of free annihilation of positrons at interfaces I 2 , thus suggesting an increase in the electron density with the filler content. The activation energy of conduction, E a , is found to decrease with the increase in the loading of conductive filler and the particle size of the filler. A correlation between the free-volume V f , and the d.c. electrical conductivity ln (Σ) is found to be in accordance with Miyamoto and Shibayma model of ion conduction.

  19. Properties of grafted polymer metal complexes as ion exchangers and its electrical conductivity

    International Nuclear Information System (INIS)

    El-Arnaouty, M.B.; Abdel Ghaffar, A.M.; Eid, M.

    2011-01-01

    The polyelectrolyte has been prepared as a potential proton exchanger polymer by grafting of acrylic acid/acrylamide and acrylic acid/acrylonitrile comonomer onto low density polyethylene film via gamma radiation. The influence of grafting percent on the electrical conductivity was studied. The resulting polymers were then characterized by evaluating their physico-chemical properties such as ion exchange capacity, and electrical conductivity as a function of grafting yield. The grafted films at different compositions was characterized by FTIR, TGA and SEM. The ion exchange capacity (IEC) of the grafted film at grafting % (191) and monomer concentration ratio 50:50 for (LDPE-g-AAc/AAm) was found to be more than that for (LDPE-g-AAc/AN). The electrical conductivity was found to be greatly affected by the comonomer composition where it increased as the degree of grafting increased for all grafted films. After alkaline treatment with 3% KOH, the electrical conductivity of the grafted films found to be increased. The presence of potassium as counter ion maximized the electrical conductivity of the grafted films. The electrical conductivity of Cu-membrane complexes was higher than that of both Co and Ni complexes. The electrical conductivity increases by increasing both Cu ions content and temperature

  20. Investigations on the Mechanical Properties of Conducting Polymer Coating-Substrate Structures and Their Influencing Factors

    Directory of Open Access Journals (Sweden)

    Xin Hua

    2009-12-01

    Full Text Available This review covers recent advances and work on the microstructure features, mechanical properties and cracking processes of conducting polymer film/coatingsubstrate structures under different testing conditions. An attempt is made to characterize and quantify the relationships between mechanical properties and microstructure features. In addition, the film cracking mechanism on the micro scale and some influencing factors that play a significant role in the service of the film-substrate structure are presented. These investigations cover the conducting polymer film/coating nucleation process, microstructure-fracture characterization, translation of brittle-ductile fractures, and cracking processes near the largest inherent macromolecule defects under thermal-mechanical loadings, and were carried out using in situ scanning electron microscopy (SEM observations, as a novel method for evaluation of interface strength and critical failure stress.

  1. Hydrothermal temperature effect on crystal structures, optical properties and electrical conductivity of ZnO nanostructures

    Science.gov (United States)

    Dhafina, Wan Almaz; Salleh, Hasiah; Daud, Mohd Zalani; Ghazali, Mohd Sabri Mohd; Ghazali, Salmah Mohd

    2017-09-01

    ZnO is an wide direct band gap semiconductor and possess rich family of nanostructures which turned to be a key role in the nanotechnology field of applications. Hydrothermal method was proven to be simple, robust and low cost among the reported methods to synthesize ZnO nanostructures. In this work, the properties of ZnO nanostructures were altered by varying temperatures of hydrothermal process. The changes in term of morphological, crystal structures, optical properties and electrical conductivity were investigated. A drastic change of ZnO nanostructures morphology and decreases of 002 diffraction peak were observed as the hydrothermal temperature increased. The band gap of samples decreased as the size of ZnO nanostructure increased, whereas the electrical conductivity had no influence on the band gap value but more on the morphology of ZnO nanostructures instead.

  2. Tetrazole amphiphile inducing growth of conducting polymers hierarchical nanostructures and their electromagnetic absorption properties

    Science.gov (United States)

    Xie, Aming; Sun, Mengxiao; Zhang, Kun; Xia, Yilu; Wu, Fan

    2018-05-01

    Conducting polymers (CPs) at nano scales endow materials with special optical, electrical, and magnetic properties. The crucial factor to construct and regulate the micro-structures of CPs is the inducing reagent, particular in its chemical structure, such active sites, self-assembling properties. In this paper, we design and synthesize an amphiphile bearing tetrazole moiety on its skeleton, and use this amphiphile as an inducing reagent to prepare and regulate the micro-structures of a series of CPs including polypyrrole, polyaniline, poly(3,4-ethylenedioxythiophene) and poly(p-phenylenediamine). Because of the unique electric properties of CPs and size effect, we next explored the electromagnetic absorption performances of these CPs nanostructures. A synergetic combination of electric loss and magnetic loss is used to explain the absorption mechanism of these CPs nano-structures.

  3. Conductivity and properties of polysiloxane-polyether cluster-LiTFSI networks as hybrid polymer electrolytes

    Science.gov (United States)

    Boaretto, Nicola; Joost, Christine; Seyfried, Mona; Vezzù, Keti; Di Noto, Vito

    2016-09-01

    This report describes the synthesis and the properties of a series of polymer electrolytes, composed of a hybrid inorganic-organic matrix doped with LiTFSI. The matrix is based on ring-like oligo-siloxane clusters, bearing pendant, partially cross-linked, polyether chains. The dependency of the thermo-mechanic and of the transport properties on several structural parameters, such as polyether chains' length, cross-linkers' concentration, and salt concentration is studied. Altogether, the materials show good thermo-mechanical and electrochemical stabilities, with conductivities reaching, at best, 8·10-5 S cm-1 at 30 °C. In conclusion, the cell performances of one representative sample are shown. The scope of this report is to analyze the correlations between structure and properties in networked and hybrid polymer electrolytes. This could help the design of optimized polymer electrolytes for application in lithium metal batteries.

  4. Electrical properties of fast ion conducting silver based borate glasses: Application in solid battery

    International Nuclear Information System (INIS)

    Masoud, Emad M.; Khairy, M.; Mousa, M.A.

    2013-01-01

    Graphical abstract: -- Highlights: •AgI dopant created more opened borate network structure. •Dielectric constant and loss values increased with AgI concentration. •AgI dopant enhanced both ion migration and orientation. •0.6 AgI–0.27 Ag 2 O–0.13 B 2 O 3 showed the highest DC-conductivity at room temperature. •It showed also good life time as a solid electrolyte in solid battery at room temperature. -- Abstract: The electrical properties of the ternary ionic conducting glass system xAgI–(1 – x)[0.67Ag 2 O–0.33B 2 O 3 ], where x = 0.4 , 0.5, 0.6, 0.7 and 0.8, were studied for emphasizing the influence of silver iodide concentration on the transport properties in the based borate glasses. The glasses were prepared by melt quenching technique and characterized using X-ray diffraction (XRD), FT-IR spectra and differential thermal analysis (DTA). XRD confirmed a glassy nature for all investigated compositions. Electrical conductivity (σ), dielectric constant (ε′), dielectric loss (ε ″ ) and impedance spectra (Z′–Z′′) were studied for all samples at a frequency range of 0–10 6 Hz and over a temperature range of 303–413 K. Changes of conductivity and dielectric properties with composition, temperature and frequency were analyzed and discussed. A silver iodine battery using glassy electrolyte sample with the highest ionic conductivity (x = 0.6) was studied

  5. Effects of Tillage Methods on Some Soil Physical Properties, Growth and Yield of Water Melon in a Semi-Arid Region of Nigeria

    Directory of Open Access Journals (Sweden)

    A. Dauda

    2017-02-01

    Full Text Available An appropriate tillage method is necessary to create an optimum seed bed condition for optimum crop growth and yield. Two-year field experiment was conducted in 2013 and 2014 to investigate the effects of different tillage methods on the physical properties of sandy loam soil, growth and yield of water melon (Citrullus vulgaris in a semi-arid environment. The Tillage treatments were disc ploughing plus disc harrowing (DP+DH, double disc ploughing (DDP, double disc harrowing (DDH, disc ploughing (DP and disc harrowing (DH as minimum tillage (MT and zero tillage (ZT and direct drilling method (control. The watermelon seeds were Planted manually placing three (3 seeds per hole at an interval of 1.5m along the rows and 50cm between the rows at an average depth of 5cm. The treatments were laid in a randomized complete block design (RCBD with four replications. Results showed that disc ploughing + disc harrowing (DP+DH was found to be more appropriate and profitable tillage method in improving soil physical properties and growth and yield of water melon in a sandy loam soil. Watermelon yield, fruit weight (FW, fruit length (FL, fruit diameter (FD and leaf area index (LAI were significantly influenced (P=0.05, but influence of tillage treatments were not significant on the number of fruit per plant (NFPP. A numerical value of 31.0t/ha, 26.0, 5.4kg, 29.0cm, and 33.8cm were recorded for maximum crop yield, NFPP, FW, FD and FL respectively in DP+DH-treated plots. For zero tillage (ZT treatment, maximum of crop yield and NFPP were 26.5t/ha and 20.0 respectively. Thus for enhanced growth and yield of watermelon, DP/DH would be more preferable. The orthodox method of zero tillage is out rightly discouraged

  6. Consequences of Ca multisite occupation for the conducting properties of BaTiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Zulueta, Y.A., E-mail: yohandysalexis.zuluetaleyva@student.kuleuven.be [Departamento de Física, Facultad de Ciencias Naturales, Universidad de Oriente, CP-90500 Santiago de Cuba (Cuba); Department of Chemistry, KU Leuven, B-3001 Leuven (Belgium); Dawson, J.A. [Department of Engineering, University of Cambridge, Cambridge CB2 1PZ (United Kingdom); Leyet, Y. [Departamento de Engenharia de Materiais, Universidade Federal do Amazonas, Av. General Rodrigo Otávio, 6200 – Coroado I, 69077-000 Manaus (Brazil); Departamento de Física, Universidade Federal do Amazonas, Av. General Rodrigo Otávio, 6200 – Coroado I, 69077-000 Manaus, Amazonas (Brazil); Anglada-Rivera, J. [Instituto Federal de Educação Ciência e Tecnologia do Amazonas, Av. 7de Setembro, 1975, 69020-120 Manaus (Brazil); Guerrero, F. [Departamento de Física, Universidade Federal do Amazonas, Av. General Rodrigo Otávio, 6200 – Coroado I, 69077-000 Manaus, Amazonas (Brazil); Silva, R.S. [Departamento de Física, Universidade Federal de Sergipe, 49100-000 São Cristóvão, SE (Brazil); Nguyen, Minh Tho [Department of Chemistry, KU Leuven, B-3001 Leuven (Belgium)

    2016-11-15

    In combination with the dielectric modulus formalism and theoretical calculations, a newly developed defect incorporation mode, which is a combination of the standard A- and B-site doping mechanisms, is used to explain the conducting properties in 5 mol% Ca-doped BaTiO{sub 3}. Simulation results for Ca solution energies in the BaTiO{sub 3} lattice show that the new oxygen vacancy inducing mixed mode exhibits low defect energies. A reduction in dc conductivity compared with undoped BaTiO{sub 3} is witnessed for the incorporation of Ca. The conducting properties of 5 mol% Ca-doped BaTiO{sub 3} are analyzed using molecular dynamics and impedance spectroscopy. The ionic conductivity activation energies for each incorporation mode are calculated and good agreement with experimental data for oxygen migration is observed. The likely existence of the proposed defect configuration is also analyzed on the basis of these methods. - Graphical abstract: Oxygen vacancy formation as a result of self-compensation in Ca-doped BaTiO{sub 3}.

  7. A Numerical Method for Analyzing Electromagnetic Scattering Properties of a Moving Conducting Object

    Directory of Open Access Journals (Sweden)

    Lei Kuang

    2014-01-01

    Full Text Available A novel numerical approach is developed to analyze electromagnetic scattering properties of a moving conducting object based on the finite-difference time-domain (FDTD algorithm. Relativistic boundary conditions are implemented into the FDTD algorithm to calculate the electromagnetic field on the moving boundary. An improved technique is proposed to solve the scattered field in order to improve the computational efficiency and stability of solutions. The time-harmonic scattered field from a one-dimensional moving conducting surface is first simulated by the proposed approach. Numerical results show that the amplitude and frequency of the scattered field suffer a modulation shift. Then the transient scattered field is calculated, and broadband electromagnetic scattering properties of the moving conducting surface are obtained by the fast Fourier transform (FFT. Finally, the scattered field from a two-dimensional moving square cylinder is analyzed. The numerical results demonstrate the Doppler effect of a moving conducting object. The simulated results agree well with analytical results.

  8. Structural, thermal and ion transport properties of radiation grafted lithium conductive polymer electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Nasef, Mohamed Mahmoud [Business and Advanced Technology Centre (BATC), Universiti Teknologi Malaysia, Jalan Semarak, 54100 Kuala Lumpur (Malaysia)]. E-mail: mahmoudeithar@mailcity.com; Saidi, Hamdani [Business and Advanced Technology Centre (BATC), Universiti Teknologi Malaysia, Jalan Semarak, 54100 Kuala Lumpur (Malaysia)

    2006-10-10

    Structural, thermal and ion transport properties of lithium conductive polymer electrolytes prepared by radiation-induced grafting of styrene onto poly(vinylidene fluoride) (PVDF) films and subsequent activation with LiPH{sub 6}/EC/DEC liquid electrolyte were investigated in correlation with the content of the grafted polystyrene (Y%). The changes in the structure were studied using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Thermal gravimetric analysis (TGA) was used to evaluate the thermal stability. The ionic conductivity was measured by means of ac impedance spectroscopy at various temperatures. The polymer electrolytes were found to undergo considerable structural and morphological changes that resulted in a noticeable increase in their ionic conductivity with the increase in Y% at various temperatures (25-65 deg. C). The ionic conductivity achieved a value of 1.61 x 10{sup -3} S cm{sup -1} when Y of the polymer electrolyte reached 50% and at 25 deg. C. The polymer electrolytes also showed a multi-step degradation behaviour and thermal stability up to 120 deg. C, which suits normal lithium battery operation temperature range. The overall results of this work suggest that the structural changes took place in PVDF matrix during the preparation of these polymer electrolytes have a strong impact on their various properties.

  9. Studying the influence of substrate conductivity on the optoelectronic properties of quantum dots langmuir monolayer

    Science.gov (United States)

    Al-Alwani, Ammar J.; Chumakov, A. S.; Begletsova, N. N.; Shinkarenko, O. A.; Markin, A. V.; Gorbachev, I. A.; Bratashov, D. N.; Gavrikov, M. V.; Venig, S. B.; Glukhovskoy, E. G.

    2018-04-01

    The formation of CdSe quantum dots (QDs) monolayers was studied by Langmuir Blodgett method. The fluorescence (PL) spectra of QD monolayers were investigated at different substrate type (glass, silicon and ITO glass) and the influence of graphene sheets layer (as a conductive surface) on the QDs properties has also been studied. The optoelectronic properties of QDs can be tuned by deposition of insulating nano-size layers of the liquid crystal between QDs and conductive substrate. The monolayer of QDs transferred on conductive surface (glass with ITO) has lowest intensity of PL spectra due to quenching effect. The PL intensity of QDs could be tuned by using various type of substrates or/and by transformed high conductive layer. Also the photooxidation processes of CdSe QDs monolayer on the solid surface can be controlled by selection of suitable substrate. The current-voltage (I–V) characteristics of QDs thin film on ITO surface was studied using scanning tunneling microscope (STM).

  10. Effect of conducting polypyrrole on the transport properties of carbon nanotube yarn

    International Nuclear Information System (INIS)

    Foroughi, Javad; Kimiaghalam, Bahram; Ghorbani, Shaban Reza; Safaei, Farzad; Abolhasan, Mehran

    2012-01-01

    Experiments were conducted to measure the electrical conductivity in three types of pristine and carbon nanotube-polypyrrole (CNT-PPy) composite yarns and its dependence on over a wide temperature range. The experimental results fit well with the analytical models developed. The effective energy separation between localized states of the pristine CNT yarn is larger than that for both the electrochemically and chemically prepared CNT-PPy yarns. It was found that all samples are in the critical regime in the insulator–metal transition, or close to the metallic regime at low temperature. The electrical conductivity results are in good agreement with a Three Dimensional Variable Range Hopping model at low temperatures, which provides a strong indication that electron hopping is the main means of current transfer in CNT yarns at T < 100 K. We found that the two shell model accurately describes the electronic properties of CNT and CNT-PPy composite yarns in the temperature range of 5–350 K. - Highlights: ► We developed hybrid carbon nanotube conducting polypyrrole composite yarns. ► The main current transfer scheme in yarn is via three dimensional electrons hopping. ► Two shell model describes well electronic properties of yarns in range of 5-350 K.

  11. Bending of conjugated molecular wires and its effect on electron conduction properties

    International Nuclear Information System (INIS)

    Das, Bidisa

    2010-01-01

    The electronic structure and electron transport properties of simple conjugated molecular wires like oligophenylene ethynylene (OPE) and oligophenylene vinylene (OPV) are studied under compression. If artificially confined to a given shorter length, the oligomers tend to bend and bending causes a loss in the overlap of the conjugated molecular orbitals. Theoretical modeling of electronic transport has been carried out for all undistorted and compressed OPE/OPV oligomers. OPV exists in step-like or V-like conformations and they have the same stability with very similar frontier molecular orbitals. The conductances of these molecular wires are calculated when inserted between two gold probes and the conductances for OPV are found to be comparable to OPE when the interfaces are same. The conductance decreases with bending due to the gradual loss in overlap of the molecular orbitals. It is also found that the conductances of the molecular wires decrease very strongly if the terminal sulfur atom is simultaneously bonded to hydrogen and a gold surface, thus reflecting the importance of the interface in determining the conductance in two-probe systems. From the conductance studies it may be concluded that if one or more benzene rings of OPE are rotated from coplanar conditions, the orthogonal molecular orbitals may completely block the electronic transport, rendering the molecule insulating.

  12. Effects of stretching and compression on conducting properties of an Au–alkanedithiol–Au molecular junction

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Fang; Zhang, Xiao-Jiao; Yu, Ji-Hai; Xu, Hua; Chu, Yu-Fang [Physics Science and Engineering Technology College, Yichun University, Yichun 336000 (China); Fan, Zhi-Qiang, E-mail: fan0221@163.com [School of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410004 (China)

    2016-03-01

    We have studied the effects of stretching and compression on the electronic properties of 7-alkanedithiol covalently linked to two Au electrodes. Results show a progressive increase in conductivity upon molecule compression and decrease with molecule stretching. The notable conductance increase at high compression is attributed to a significant modification of HOMO and LUMO orbitals of the junction, which enhances electron delocalization and promotes tunneling across the junction. More important, the current switching ratios between the various stages of compressed/extended geometries almost maintain the constant values on the bias region from 0 V to 2 V. In other word, the mechanically-induced conductance enhancement and weakening are stable within a large bias voltage range.

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

    Science.gov (United States)

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

    2012-11-01

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

  14. Electrical properties and conduction mechanisms of Ru-based thick-film (cermet) resistors

    International Nuclear Information System (INIS)

    Pike, G.E.; Seager, C.H.

    1977-01-01

    This paper presents an experimental study of the electrical conduction mechanisms in thick-film (cermet) resistor. The resistors were made from one custom and three commercially formulated inks with sheet resistivities ranging from 10 2 to 10 6 Ω/D 7 Alembertian in decade increments. Their microstructure and composition have been examined using optical and scanning electron microscopy, electron microprobe analysis, x-ray diffraction, and various chemical analyses. This portion of our study shows that the resistors are heterogeneous mixtures of metallic metal oxide particles (approx.4 x 10 -5 cm in diameter) and a lead silicate glass. The metal oxide particles are ruthenium containing pyrochlores, and are joined to form a continuous three-dimensional network of chain segments. The principal experimental work reported here is an extensive study of the electrical transport properties of the resistors. The temperature dependence of conductance has been measured from 1.2 to 400 K, and two features common to all resistors are found. There is a pronounced decrease in conductance at low temperatures and a shallow maximum at several hundred Kelvin. Within the same range of temperatures the reversible conductance as a function of electric field from 0 to 28 kV/cm has been studied. The resistors are non-Ohmic at all temperatures, but particularly at cryogenic temperatures for low fields. At higher fields the conductance shows a linear variation with electric field. The thick-film resistors are found to have a small dielectric constant and a (nearly) frequency-independent conductance from dc to 50 MHz. The magnetoresistance to 100 kG, the Hall mobility, and the Seebeck coefficient of most of the resistors have been measured and discovered to be quite small. Many of the electrical transport properties have also been determined for the metal oxide particles which were extracted from the fired resistors

  15. The structure of new germanates, gallates, borates and silicates with laser, piezo, ferroelectric and ion conducting properties

    International Nuclear Information System (INIS)

    Belokonev, E.L.

    1994-01-01

    The results of structure investigation of more than 50 new crystalline germanates, gallates, borogermanates, borates, and silicates with laser, piezo, ferroelectric, and ion-conducting properties are described. The structure - properties relationship is examined. 71 refs.; 24 figs.; 10 tabs

  16. The effects of MWNT on thermal conductivity and thermal mechanical properties of epoxy

    Science.gov (United States)

    Ismadi, A. I.; Othman, R. N.

    2017-12-01

    Multiwall nanotube (MWNT) was used as filler in various studies to improve thermal conductivity and mechanical properties of epoxy. Present study varied different weight loading (0, 0.1 %, 0.5 %, 1 %, 1.5 %, 3 % and 5 %) of MWNT in order to observe the effects on the epoxy. Nanocomposite was analyzed by dynamic-mechanical thermal analyser (DMTA) and KD2 pro analyzer. DMTA measured storage modulus (E') and glass transition temperature (Tg) of the nanocomposite. Result showed that Tg value of neat epoxy is higher than all MWNT epoxy nanocomposite. Tg values drop from 81.55 °C (neat epoxy) to 65.03 °C (at 0.1 wt%). This may happen due to the agglomeration of MWNT in the epoxy. However, Tg values increases with the increase of MWNT wt%. Tg values increased from 65.03 °C to 78.53 °C at 1 wt%. Increment of storage modulus (E') at 3 °C (glassy region) was observed as the MWNT loading increases. Maximum value of E' during glassy region was observed to be at 5 wt% with (7.26±0.7) E+08 Pa compared to neat epoxy. On the contrary, there is slight increased and slight decreased with E' values at 100 °C (rubbery region) for all nanocomposite. Since epoxy exhibits low thermal conductivity properties, addition of MWNT has enhanced the properties. Optimum value of thermal conductivity was observed at 3 wt%. The values increased up to 9.03 % compared to neat epoxy. As expected, the result showed decrease value in thermal conductivity at 5 wt% as a result of agglomeration of MWNT in the epoxy.

  17. Detection and differentiation of pollution in urban surface soils using magnetic properties in arid and semi-arid regions of northwestern China

    International Nuclear Information System (INIS)

    Wang, Bo; Xia, Dunsheng; Yu, Ye; Jia, Jia; Xu, Shujing

    2014-01-01

    Increasing urbanization and industrialization over the world has caused many social and environmental problems, one of which drawing particular concern is the soil pollution and its ecological degradation. In this study, the efficiency of magnetic methods for detecting and discriminating contaminates in the arid and semi-arid regions of northwestern China was investigated. Topsoil samples from six typical cities (i.e. Karamay, Urumqi, Lanzhou, Yinchuan, Shizuishan and Wuhai) were collected and a systematic analysis of their magnetic properties was conducted. Results indicate that the topsoil samples from the six cities were all dominated by coarse low-coercivity magnetite. In addition, the average magnetite contents in the soils from Urumqi and Lanzhou were shown to be much higher than those from Karamay, Yinchuan, Shizuishan and Wuhai, and they also have relatively higher χ lf and χ fd % when compared with cities in eastern China. Moreover, specific and distinctive soil pollution signals were identified at each sampling site using the combined various magnetic data, reflecting distinct sources. Industrial and traffic-derived pollution was dominant in Urumqi and Lanzhou, in Yinchuan industrial progress was observed to be important with some places affected by vehicle emission, while Karamay, Shizuishan and Wuhai were relatively clean. The magnetic properties of these latter three cities are significantly affected by both anthropogenic pollution and local parent materials from the nearby Gobi desert. The differences in magnetic properties of topsoil samples affected by mixed industrial and simplex traffic emissions are not obvious, but significant differences exist in samples affected by simplex industrial/vehicle emissions and domestic pollution. The combined magnetic analyses thus provide a sensitive and powerful tool for classifying samples according to likely sources, and may even provide a valuable diagnostic tool for discriminating among different cities

  18. Electrical Properties of Conductive Cotton Yarn Coated with Eosin Y Functionalized Reduced Graphene Oxide.

    Science.gov (United States)

    Kim, Eunju; Arul, Narayanasamy Sabari; Han, Jeong In

    2016-06-01

    This study reports the fabrication and investigation of the electrical properties of two types of conductive cotton yarns coated with eosin Y or eosin B functionalized reduced graphene (RGO) and bare graphene oxide (GO) using dip-coating method. The surface morphology of the conductive cotton yarn coated with reduced graphene oxide was observed by Scanning Electron Microscope (SEM). Due to the strong electrostatic attractive forces, the negatively charged surface such as the eosin Y functionalized reduced graphene oxide or bare GO can be easily coated to the positively charged polyethyleneimine (PEI) treated cotton yarn. The maximum current for the conductive cotton yarn coated with eosin Y functionalized RGO and bare GO with 20 cycles repetition of (5D + R) process was found to be 793.8 μA and 3482.8 μA. Our results showed that the electrical conductivity of bare GO coated conductive cotton yarn increased by approximately four orders of magnitude with the increase in the dipping cycle of (5D+R) process.

  19. DC conductivity of twisted bilayer graphene: Angle-dependent transport properties and effects of disorder

    Science.gov (United States)

    Andelković, M.; Covaci, L.; Peeters, F. M.

    2018-03-01

    The in-plane dc conductivity of twisted bilayer graphene is calculated using an expansion of the real-space Kubo-Bastin conductivity in terms of Chebyshev polynomials. We investigate within a tight-binding approach the transport properties as a function of rotation angle, applied perpendicular electric field, and vacancy disorder. We find that for high-angle twists, the two layers are effectively decoupled, and the minimum conductivity at the Dirac point corresponds to double the value observed in monolayer graphene. This remains valid even in the presence of vacancies, hinting that chiral symmetry is still preserved. On the contrary, for low twist angles, the conductivity at the Dirac point depends on the twist angle and is not protected in the presence of disorder. Furthermore, for low angles and in the presence of an applied electric field, we find that the chiral boundary states emerging between AB and BA regions contribute to the dc conductivity, despite the appearance of localized states in the AA regions. The results agree qualitatively with recent transport experiments in low-angle twisted bilayer graphene.

  20. Experimental Investigation of Surface Layer Properties of High Thermal Conductivity Tool Steel after Electrical Discharge Machining

    Directory of Open Access Journals (Sweden)

    Rafał Świercz

    2017-12-01

    Full Text Available New materials require the use of advanced technology in manufacturing complex shape parts. One of the modern materials widely used in the tool industry for injection molds or hot stamping dies is high conductivity tool steel (HTCS 150. Due to its hardness (55 HRC and thermal conductivity at 66 W/mK, this material is difficult to machine by conventional treatment and is being increasingly manufactured by nonconventional technology such as electrical discharge machining (EDM. In the EDM process, material is removed from the workpiece by a series of electrical discharges that cause changes to the surface layers properties. The final state of the surface layer directly influences the durability of the produced elements. This paper presents the influence of EDM process parameters: discharge current Ic and the pulse time ton on surface layer properties. The experimental investigation was carried out with an experimental methodology design. Surface layers properties including roughness 3D parameters, the thickness of the white layer, heat affected zone, tempered layer and occurring micro cracks were investigated and described. The influence of the response surface methodology (RSM of discharge current Ic and the pulse time ton on the thickness of the white layer and roughness parameters Sa, Sds and Ssc were described and established.

  1. Properties of TiO{sub 2}-based transparent conducting oxides

    Energy Technology Data Exchange (ETDEWEB)

    Hitosugi, Taro [Kanagawa Academy of Science and Technology (KAST), 213-0012 Kawasaki (Japan); Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 980-8577 Sendai (Japan); Yamada, Naoomi; Nakao, Shoichiro [Kanagawa Academy of Science and Technology (KAST), 213-0012 Kawasaki (Japan); Hirose, Yasushi; Hasegawa, Tetsuya [Kanagawa Academy of Science and Technology (KAST), 213-0012 Kawasaki (Japan); Department of Chemistry, University of Tokyo, 113-0033 Tokyo (Japan)

    2010-07-15

    The development and properties of titanium dioxide (TiO{sub 2})-based transparent conducting oxides (TCO), which exhibit properties comparable to those of In{sub 2-x}Sn{sub x}O{sub 3} (ITO), are reviewed in this article. An epitaxial thin film of anatase Ti{sub 0.94}Nb{sub 0.06}O{sub 2} exhibited a resistivity ({rho}) of 2.3 x 10{sup -4}{omega} cm and internal transmittance of {proportional_to}95% in the visible light region. Furthermore, we prepared polycrystalline films with {rho} of 6.4 x 10{sup -4}{omega} cm at room temperature on glass substrates by using sputtering. We focus on characteristics unique to TiO{sub 2}-based TCO, such as a high refractive index, high transmittance in infrared, and high stability in reducing atmospheres. Possible applications of TiO{sub 2}-based TCOs, as well as the mechanism of the transparent conducting properties found in this d-electron-based TCO, are discussed in this review. Photograph showing TiO{sub 2}-based TCO on a transparent plastic film. Note that the film appears greenish due to interference in the film originating from its high refractive index. This high refractive index is one of the unique characteristics of TiO{sub 2}-based TCO. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  2. Effects Of Elevated Ozone On Leaf {delta} {sup 13} C And Leaf Conductance Of Plant Species Grown In Semi-Natural Grassland With Or Without Irrigation

    Energy Technology Data Exchange (ETDEWEB)

    Jaeggi, M.; Saurer, M.; Volk, M. [Agroscope-FAL (Switzerland); Fuhrer, J. [Agroscope-FAL (Switzerland)

    2005-03-01

    At the Swiss prealpine site Le Mouret (754 m a.s.l. 46deg 45min N / 7deg 10min E), semi-natural grassland species were kept under ambient or elevated ozone, paired with or without additional irrigation. Two of the four investigated grassland species showed an additive increase in {sup 13}C-values under drought and elevated ozone conditions. (author)

  3. Electrical anisotropy properties of ZnO nanorods analyzed by conductive atomic force microscopy

    International Nuclear Information System (INIS)

    Wu Yunfeng; Yu Naisen; Liu Dongping; He Yangyang; Liu Yuanda; Liang Hongwei; Du Guotong

    2013-01-01

    Highlights: ► The electrical properties of one individual lying ZnO nanorod were performed by C-AFM measurement. ► Inhomogeneous spatial current distribution was detected. ► Current was detected along the side facets while no current was detected in the top plane for ZnO nanorod. ► The side facets were more conductive than the top facets of ZnO nanorods. - Abstract: In this study, we have prepared ZnO nanorods on cracked GaN substrates using aqueous solution method. Unique electrical characterization of one individual lying ZnO nanorod is analyzed by conductive atomic force microscopy (C-AFM). Effect of anisotropy properties on the conductivity of a single nanorod has been investigated. The current maps of ZnO nanorods have been simultaneously recorded with the topography which is gained by AFM-contact mode. The C-AFM measurement present local current–voltage (I–V) characteristics of the side facets of one individual lying nanorod, however, no current is detected on the top facets of ZnO nanorods. Measurement results indicate that the side facets are more electrically active than the top facets of ZnO nanorods due to lower Schottky barrier height of the side facets.

  4. Prediction of thermal conductivity of rock through physico-mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Singh, T.N. [Department of Earth Sciences, Indian Institute of Technology, Bombay 400 076 (India); Sinha, S.; Singh, V.K. [Institute of Technology, Banaras Hindu University, Varanasi 221 005 (India)

    2007-01-15

    The transfer of energy between two adjacent parts of rock mainly depends on its thermal conductivity. Present study supports the use of artificial neural network (ANN) and adaptive neuro fuzzy inference system (ANFIS) in the study of thermal conductivity along with other intrinsic properties of rock due to its increasing importance in many areas of rock engineering, agronomy and geo environmental engineering field. In recent years, considerable effort has been made to develop techniques to determine these properties. Comparative analysis is made to analyze the capabilities among six different models of ANN and ANFIS. ANN models are based on feedforward backpropagation network with training functions resilient backpropagation (RP), one step secant (OSS) and Powell-Beale restarts (CGB) and radial basis with training functions generalized regression neural network (GRNN) and more efficient design radial basis network (NEWRB). A data set of 136 has been used for training different models and 15 were used for testing purposes. A statistical analysis is made to show the consistency among them. ANFIS is proved to be the best among all the networks tried in this case with average absolute percentage error of 0.03% and regression coefficient of 1, whereas best performance shown by the FFBP (RP) with average absolute error of 2.26%. Thermal conductivity is predicted using P-wave velocity, porosity, bulk density, uniaxial compressive strength of rock as input parameters. (author)

  5. Effect of the interface on the mechanical properties and thermal conductivity of bismuth telluride films

    Science.gov (United States)

    Lai, Tang-Yu; Wang, Kuan-Yu; Fang, Te-Hua; Huang, Chao-Chun

    2018-02-01

    Bismuth telluride (Bi2Te3) is a type of thermoelectric material used for energy generation that does not cause pollution. Increasing the thermoelectric conversion efficiency (ZT) is one of the most important steps in the development of thermoelectric components. In this study, we use molecular dynamics to investigate the mechanical properties and thermal conductivity of quintuple layers of Bi2Te3 nanofilms with different atomic arrangements at the interface and study the effects of varying layers, angles, and grain boundaries. The results indicate that the Bi2Te3 nanofilm perfect substrate has the ideal Young’s modulus and thermal conductivity, and the maximum yield stress is observed for a thickness of ∼90 Å. As the interface changed, the structural disorder of atomic arrangement affected the mechanical properties; moreover, the phonons encounter lattice disordered atomic region will produce scattering reduce heat conduction. The results of this investigation are helpful for the application of Bi2Te3 nanofilms as thermoelectric materials.

  6. Edge magnetism impact on electrical conductance and thermoelectric properties of graphenelike nanoribbons

    Science.gov (United States)

    Krompiewski, Stefan; Cuniberti, Gianaurelio

    2017-10-01

    Edge states in narrow quasi-two-dimensional nanostructures determine, to a large extent, their electric, thermoelectric, and magnetic properties. Nonmagnetic edge states may quite often lead to topological-insulator-type behavior. However, another scenario develops when the zigzag edges are magnetic and the time reversal symmetry is broken. In this work we report on the electronic band structure modifications, electrical conductance, and thermoelectric properties of narrow zigzag nanoribbons with spontaneously magnetized edges. Theoretical studies based on the Kane-Mele-Hubbard tight-binding model show that for silicene, germanene, and stanene both the Seebeck coefficient and the thermoelectric power factor are strongly enhanced for energies close to the charge neutrality point. A perpendicular gate voltage lifts the spin degeneracy of energy bands in the ground state with antiparallel magnetized zigzag edges and makes the electrical conductance significantly spin polarized. Simultaneously the gate voltage worsens the thermoelectric performance. Estimated room-temperature figures of merit for the aforementioned nanoribbons can exceed a value of 3 if phonon thermal conductances are adequately reduced.

  7. Properties of polyacrylic acid-coated silver nanoparticle ink for inkjet printing conductive tracks on paper with high conductivity

    International Nuclear Information System (INIS)

    Huang, Qijin; Shen, Wenfeng; Xu, Qingsong; Tan, Ruiqin; Song, Weijie

    2014-01-01

    Silver nanoparticles with a mean diameter of approximately 30 nm were synthesized by reduction of silver nitrate with triethanolamine in the presence of polyacrylic acid. Silver nanoparticle-based ink was prepared by dispersing silver nanoparticles into a mixture of water and ethylene glycol. The mechanism for the dispersion and aggregation of silver nanoparticles in ink is discussed. The strong electrostatic repulsions of the carboxylate anions of the adsorbed polyacrylic acid molecules disturbed the aggregation of metal particles in solutions with a high pH value (pH > 5). An inkjet printer was used to deposit this silver nanoparticle-based ink to form silver patterns on photo paper. The actual printing qualities of the silver tracks were then analyzed by variation of printing passes, sintering temperature and time. The results showed that sintering temperature and time are associated strongly with the conductivity of the inkjet-printed conductive patterns. The conductivity of printed patterns sintered at 150 °C increased to 2.1 × 10 7  S m −1 , which was approximately one third that of bulk silver. In addition, silver tracks on paper substrate also showed better electrical performance after folding. This study demonstrated that the resulting ink-jet printed patterns can be used as conductive tracks in flexible electronic devices. - Highlights: • An ink from silver nanoparticles coated with polyacrylic acid was prepared. • The ink was used for inkjet-printed tracks at varying printing parameters. • The conductivity of printed tracks sintered at 150 °C increased to 2.1 × 10 7  S/m. • Mechanism for dispersion and aggregation of the nanoparticles in ink is discussed

  8. Properties of polyacrylic acid-coated silver nanoparticle ink for inkjet printing conductive tracks on paper with high conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Qijin [Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201 (China); Shen, Wenfeng, E-mail: wfshen@nimte.ac.cn [Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201 (China); Xu, Qingsong [Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201 (China); Tan, Ruiqin [Faculty of Information Science and Engineering, Ningbo University, Ningbo, Zhejiang 315211 (China); Song, Weijie, E-mail: weijiesong@nimte.ac.cn [Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201 (China)

    2014-10-15

    Silver nanoparticles with a mean diameter of approximately 30 nm were synthesized by reduction of silver nitrate with triethanolamine in the presence of polyacrylic acid. Silver nanoparticle-based ink was prepared by dispersing silver nanoparticles into a mixture of water and ethylene glycol. The mechanism for the dispersion and aggregation of silver nanoparticles in ink is discussed. The strong electrostatic repulsions of the carboxylate anions of the adsorbed polyacrylic acid molecules disturbed the aggregation of metal particles in solutions with a high pH value (pH > 5). An inkjet printer was used to deposit this silver nanoparticle-based ink to form silver patterns on photo paper. The actual printing qualities of the silver tracks were then analyzed by variation of printing passes, sintering temperature and time. The results showed that sintering temperature and time are associated strongly with the conductivity of the inkjet-printed conductive patterns. The conductivity of printed patterns sintered at 150 °C increased to 2.1 × 10{sup 7} S m{sup −1}, which was approximately one third that of bulk silver. In addition, silver tracks on paper substrate also showed better electrical performance after folding. This study demonstrated that the resulting ink-jet printed patterns can be used as conductive tracks in flexible electronic devices. - Highlights: • An ink from silver nanoparticles coated with polyacrylic acid was prepared. • The ink was used for inkjet-printed tracks at varying printing parameters. • The conductivity of printed tracks sintered at 150 °C increased to 2.1 × 10{sup 7} S/m. • Mechanism for dispersion and aggregation of the nanoparticles in ink is discussed.

  9. Identification of conduction and hot electron property in ZnS, ZnO and SiO2

    International Nuclear Information System (INIS)

    Huang Jinzhao; Xu Zheng; Zhao Suling; Li Yuan; Yuan Guangcai; Wang Yongsheng; Xu Xurong

    2007-01-01

    The impact excitation and ionization is the most important process in layered optimization scheme and solid state cathodoluminescence. The conduction property (semiconductor property) of SiO 2 , ZnS and ZnO is studied based on organic/inorganic electroluminescence. The hot electron property (acceleration and multiplication property) of SiO 2 and ZnS is investigated based on the solid state cathodoluminescence. The results show that the SiO 2 has the fine hot electron property and the conduction property is not as good as ZnO and ZnS

  10. Thermal Properties and Phonon Spectral Characterization of Synthetic Boron Phosphide for High Thermal Conductivity Applications.

    Science.gov (United States)

    Kang, Joon Sang; Wu, Huan; Hu, Yongjie

    2017-12-13

    Heat dissipation is an increasingly critical technological challenge in modern electronics and photonics as devices continue to shrink to the nanoscale. To address this challenge, high thermal conductivity materials that can efficiently dissipate heat from hot spots and improve device performance are urgently needed. Boron phosphide is a unique high thermal conductivity and refractory material with exceptional chemical inertness, hardness, and high thermal stability, which holds high promises for many practical applications. So far, however, challenges with boron phosphide synthesis and characterization have hampered the understanding of its fundamental properties and potential applications. Here, we describe a systematic thermal transport study based on a synergistic synthesis-experimental-modeling approach: we have chemically synthesized high-quality boron phosphide single crystals and measured their thermal conductivity as a record-high 460 W/mK at room temperature. Through nanoscale ballistic transport, we have, for the first time, mapped the phonon spectra of boron phosphide and experimentally measured its phonon mean free-path spectra with consideration of both natural and isotope-pure abundances. We have also measured the temperature- and size-dependent thermal conductivity and performed corresponding calculations by solving the three-dimensional and spectral-dependent phonon Boltzmann transport equation using the variance-reduced Monte Carlo method. The experimental results are in good agreement with that predicted by multiscale simulations and density functional theory, which together quantify the heat conduction through the phonon mode dependent scattering process. Our finding underscores the promise of boron phosphide as a high thermal conductivity material for a wide range of applications, including thermal management and energy regulation, and provides a detailed, microscopic-level understanding of the phonon spectra and thermal transport mechanisms of

  11. Improved dielectric properties, mechanical properties, and thermal conductivity properties of polymer composites via controlling interfacial compatibility with bio-inspired method

    Science.gov (United States)

    Ruan, Mengnan; Yang, Dan; Guo, Wenli; Zhang, Liqun; Li, Shuxin; Shang, Yuwei; Wu, Yibo; Zhang, Min; Wang, Hao

    2018-05-01

    Surface functionalization of Al2O3 nano-particles by mussel-inspired poly(dopamine) (PDA) was developed to improve the dielectric properties, mechanical properties, and thermal conductivity properties of nitrile rubber (NBR) matrix. As strong adhesion of PDA to Al2O3 nano-particles and hydrogen bonds formed by the catechol groups of PDA and the polar acrylonitrile groups of NBR, the dispersion of Al2O3-PDA/NBR composites was improved and the interfacial force between Al2O3-PDA and NBR matrix was enhanced. Thus, the Al2O3-PDA/NBR composites exhibited higher dielectric constant, better mechanical properties, and larger thermal conductivity comparing with Al2O3/NBR composites at the same filler content. The largest thermal conductivity of Al2O3-PDA/NBR composite filled with 30 phr Al2O3-PDA was 0.21 W/m K, which was 122% times of pure NBR. In addition, the Al2O3-PDA/NBR composite filled with 30 phr Al2O3-PDA displayed a high tensile strength about 2.61 MPa, which was about 255% of pure NBR. This procedure is eco-friendly and easy handling, which provides a promising route to polymer composites in application of thermal conductivity field.

  12. Stiffness effect of conductive composite powder on electrical properties of ACF for FPD

    Science.gov (United States)

    Kim, Taesung; Moon, Hyuk-Soo; Choi, Chang-Hee; Lee, Duck-Hoon

    1999-12-01

    Elastic moduli of C/Ps were varied to develop an epoxy-based reparable thermosetting ACF for FPD without causing bounce-up in the contact resistance and fracture of the conductive composite powders (C/Ps). The modification of the elastic properties of the C/Ps was done by modulating of the elastic properties of the Polystyrene (PS) bead that is the core of the C/P. The elastic properties of the PS bead changed by crosslinking degree during seeded emulsion polymerization. A simulation based on the experimental results was done to find the optimum mechanical properties of C/Ps for future finer pitch size application. For better simulation, both cases (with/without consideration of interfacial friction and slip) were compared. From these experiments, the following results were confirmed. C//P stiffness was controlled by a change of cross-linking density of the PS bead. The mechanical behaviors between the C/P and PS bead were similar within error range. When the cross-linking density of the C/P was less than 50%, the C/P could be deformed over 40% without fracture. Also, the ACF with a 50% cross-linking density C/P didnt show any bounce-up in C/Ps contact resistance and fracture. Although differences between the cases (with and without consideration of interfacial friction and slip) were observed, neither case matched the experimental result. For a closer simulation, a variation in factional coefficient is needed.

  13. Electrical conduction and NO{sub 2} gas sensing properties of ZnO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Şahin, Yasin [Council of Forensic Medicine, Bahçelievler, 34196 Istanbul (Turkey); Öztürk, Sadullah, E-mail: sadullahozturk@gyte.edu.tr [Gebze Institute of Technology, Science Faculty, Department of Physics, 41400 Gebze, Kocaeli (Turkey); Kılınç, Necmettin [Gebze Institute of Technology, Science Faculty, Department of Physics, 41400 Gebze, Kocaeli (Turkey); Koc University, Department of Electrical and Electronics Engineering, Sariyer, 34450 Istanbul (Turkey); Kösemen, Arif [Gebze Institute of Technology, Science Faculty, Department of Physics, 41400 Gebze, Kocaeli (Turkey); Mus Alparslan University, Department of Physics, 49100 Mus (Turkey); Erkovan, Mustafa [SAKARYA University, Engineering Faculty, Department of Metallurgical and Materials Engineering, Esentepe Campus, 54187 Sakarya (Turkey); Öztürk, Zafer Ziya [Gebze Institute of Technology, Science Faculty, Department of Physics, 41400 Gebze, Kocaeli (Turkey); TÜBİTAK-Marmara Research Center, Materials Institute, 41470 Gebze, Kocaeli (Turkey)

    2014-06-01

    Thermally stimulated current (TSC), photoresponse and gas sensing properties of zinc oxide (ZnO) nanorods were investigated depending on heating rates, illumination and dark aging times with using sandwich type electrode system. Vertically aligned ZnO nanorods were grown on indium tin oxide (ITO) coated glass substrate by hydrothermal process. TSC measurements were performed at different heating rates under constant potential. Photoresponse and gas sensing properties were investigated in dry air ambient at 200 °C. For gas sensing measurements, ZnO nanorods were exposed to NO{sub 2} (100 ppb to 1 ppm) in dark and illuminated conditions and the resulting resistance transient was recorded. It was found from dark electrical measurements that the dependence of the dc conductivity on temperature followed Mott's variable range hopping (VRH) model. In addition, response time and recovery times of ZnO nanorods to NO{sub 2} gas decreased by exposing to white light.

  14. Electromagnetic Scattering from a PEC Wedge Capped with Cylindrical Layers with Dielectric and Conductive Properties

    Directory of Open Access Journals (Sweden)

    H. Ozturk

    2017-04-01

    Full Text Available Electromagnetic scattering from a layered capped wedge is studied. The wedge is assumed infinite in z-direction (longitudinal and capped with arbitrary layers of dielectric with varying thicknesses and dielectric properties including conductive loss. Scalar Helmholtz equation in two dimensions is formulated for each solution region and a matrix of unknown coefficients are arrived at for electric field representation. Closed form expressions are derived for 2- and 3-layer geometries. Numerical simulations are performed for different wedge shapes and dielectric layer properties and compared to PEC-only case. It has been shown that significant reduction in scattered electric field can be obtained with 2- and 3-layered cap geometries. Total electric field in the far field normalized to incident field is also computed as a precursor to RCS analysis. Analytical results can be useful in radar cross section analysis for aerial vehicles.

  15. Thermophysical properties of proton conducting perovskite: BaCeO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Shukla, Aarti, E-mail: aarti.phy@gmail.com; Parey, Vanshree; Thakur, Rasna; Shrivastava, Archana; Gaur, N. K. [Department of Physics, Barkatullah University, Bhopal-462026 (India)

    2015-06-24

    We present the thermal properties of the proton conducting orthorhombic BaCeO{sub 3} by the means of a Rigid Ion Model (RIM). We report the cohesive energy (φ), Reststrahlen frequency (υ), Debye temperature (θ{sub D}) and Gruneisen parameter (γ). The value of Gruneisen parameter (γ), which supports the earlier, reported values. Besides, the specific heat values presented in this work by using RIM are in reasonable agreement with the available experimental data for BaCeO{sub 3} at low temperature (2K ≤ T ≤ 300K)

  16. Design and Fabrication of a Soil Moisture Meter Using Thermal Conductivity Properties of Soil

    Directory of Open Access Journals (Sweden)

    Subir DAS

    2011-09-01

    Full Text Available Study of soil for agricultural purposes is one of the main focuses of research since the beginning of civilization as food related requirements is closely linked with the soil. The study of soil has generated an interest among the researchers for very similar other reasons including understanding of soil water dynamics, evolution of agricultural water stress and validation of soil moisture modeling. In this present work design of a soil moisture measurement meter using thermal conductivity properties of soil has been proposed and experimental results are reported.

  17. Dynamic properties of silica aerogels as deduced from specific-heat and thermal-conductivity measurements

    DEFF Research Database (Denmark)

    Bernasconi, A.; Sleator, T.; Posselt, D.

    1992-01-01

    The specific heat C(p) and the thermal conductivity lambda of a series of base-catalyzed silica aerogels have been measured at temperatures between 0.05 and 20 K. The results confirm that the different length-scale regions observed in the aerogel structure are reflected in the dynamic behavior of...... SiO2 are most likely not due to fractal behavior....... the possibility of two spectral dimensions characterizing the fracton modes. Our data imply important differences between the physical mechanisms dominating the low-temperature behavior of aerogels and dense glasses, respectively. From our analysis we also conclude that the low-temperature properties of amorphous...

  18. Sulfonation degree effect on ion-conducting SPEEK-titanium oxide membranes properties

    Energy Technology Data Exchange (ETDEWEB)

    Marrero, Jacqueline Costa; Gomes, Ailton de Souza; Dutra Filho, José Carlos, E-mail: jacquecosta@gmail.com [Universidade Federal do Rio de Janeiro (IMA/UFRJ), RJ (Brazil). Instituto de Macromoléculas Professora Eloisa Mano; Hui, Wang Shu [Universidade de São Paulo (USP), São Paulo, SP (Brazil). Departamento de Engenharia Metalúrgica e de Materiais; Oliveira, Vivianna Silva de [Escola Técnica Rezende Rammel (ETRR), Rio de Janeiro, RJ (Brazil)

    2017-07-01

    Polymeric membranes were developed using a SPEEK (sulfonated poly(ether ether ketone)) polymer matrix, containing titanium oxide (TiO{sub 2}) (incorporated by sol-gel method). SPEEK with different sulfonation degrees (SD): 63% and 50% were used. The influence of sulfonation degree on membrane properties was investigated. The thermal analysis (TGA and DTGA) and X-ray diffraction (XRD) were carried out to characterize the membranes and electrochemical impedance spectroscopy (EIS) was carried out to evaluate the proton conductivity of the membranes. The proton conductivities in water were of 3.25 to 37.08 mS.cm{sup -1}. Experimental data of impedance spectroscopy were analyzed with equivalent circuits using the Zview software, and the results showed that, the best fitted was at 80 °C. (author)

  19. Analytical Solution of the Hyperbolic Heat Conduction Equation for Moving Semi-Infinite Medium under the Effect of Time-Dependent Laser Heat Source

    Directory of Open Access Journals (Sweden)

    R. T. Al-Khairy

    2009-01-01

    source, whose capacity is given by (,=((1−− while the semi-infinite body has insulated boundary. The solution is obtained by Laplace transforms method, and the discussion of solutions for different time characteristics of heat sources capacity (constant, instantaneous, and exponential is presented. The effect of absorption coefficients on the temperature profiles is examined in detail. It is found that the closed form solution derived from the present study reduces to the previously obtained analytical solution when the medium velocity is set to zero in the closed form solution.

  20. Interplay of activation kinetics and the derivative conductance determines resonance properties of neurons

    Science.gov (United States)

    Pena, Rodrigo F. O.; Ceballos, Cesar C.; Lima, Vinicius; Roque, Antonio C.

    2018-04-01

    In a neuron with hyperpolarization activated current (Ih), the correct input frequency leads to an enhancement of the output response. This behavior is known as resonance and is well described by the neuronal impedance. In a simple neuron model we derive equations for the neuron's resonance and we link its frequency and existence with the biophysical properties of Ih. For a small voltage change, the component of the ratio of current change to voltage change (d I /d V ) due to the voltage-dependent conductance change (d g /d V ) is known as derivative conductance (GhDer). We show that both GhDer and the current activation kinetics (characterized by the activation time constant τh) are mainly responsible for controlling the frequency and existence of resonance. The increment of both factors (GhDer and τh) greatly contributes to the appearance of resonance. We also demonstrate that resonance is voltage dependent due to the voltage dependence of GhDer. Our results have important implications and can be used to predict and explain resonance properties of neurons with the Ih current.

  1. Conductive properties of switchable photoluminescence thermosetting systems based on liquid crystals.

    Science.gov (United States)

    Tercjak, Agnieszka; Gutierrez, Junkal; Ocando, Connie; Mondragon, Iñaki

    2010-03-16

    Conductive properties of different thermosetting materials modified with nematic 4'-(hexyl)-4-biphenyl-carbonitrile (HBC) liquid crystal and rutile TiO(2) nanoparticles were successfully studied by means of tunneling atomic force miscroscopy (TUNA). Taking into account the liquid crystal state of the HBC at room temperature, depending on both the HBC content and the presence of TiO(2) nanoparticles, designed materials showed different TUNA currents passed through the sample. The addition of TiO(2) nanoparticles into the systems multiply the detected current if compared to the thermosetting systems without TiO(2) nanoparticles and simultaneously stabilized the current passed through the sample, making the process reversible since the absolute current values were almost the same applying both negative and positive voltage. Moreover, thermosetting systems modified with liquid crystals with and without TiO(2) nanoparticles are photoluminescence switchable materials as a function of temperature gradient during repeatable heating/cooling cycle. Conductive properties of switchable photoluminescence thermosetting systems based on liquid crystals can allow them to find potential application in the field of photoresponsive devices, with a high contrast ratio between transparent and opaque states.

  2. Statistical properties of Joule heating rate, electric field and conductances at high latitudes

    Directory of Open Access Journals (Sweden)

    A. T. Aikio

    2009-07-01

    Full Text Available Statistical properties of Joule heating rate, electric field and conductances in the high latitude ionosphere are studied by a unique one-month measurement made by the EISCAT incoherent scatter radar in Tromsø (66.6 cgmlat from 6 March to 6 April 2006. The data are from the same season (close to vernal equinox and from similar sunspot conditions (about 1.5 years before the sunspot minimum providing an excellent set of data to study the MLT and Kp dependence of parameters with high temporal and spatial resolution.

    All the parameters show a clear MLT variation, which is different for low and high Kp conditions. Our results indicate that the response of morning sector conductances and conductance ratios to increased magnetic activity is stronger than that of the evening sector. The co-location of Pedersen conductance maximum and electric field maximum in the morning sector produces the largest Joule heating rates 03–05 MLT for Kp≥3. In the evening sector, a smaller maximum occurs at 18 MLT. Minimum Joule heating rates in the nightside are statistically observed at 23 MLT, which is the location of the electric Harang discontinuity.

    An important outcome of the paper are the fitted functions for the Joule heating rate as a function of electric field magnitude, separately for four MLT sectors and two activity levels (Kp<3 and Kp≥3. In addition to the squared electric field, the fit includes a linear term to study the possible anticorrelation or correlation between electric field and conductance. In the midday sector, positive correlation is found as well as in the morning sector for the high activity case. In the midnight and evening sectors, anticorrelation between electric field and conductance is obtained, i.e. high electric fields are associated with low conductances. This is expected to occur in the return current regions adjacent to

  3. Statistical properties of Joule heating rate, electric field and conductances at high latitudes

    Directory of Open Access Journals (Sweden)

    A. T. Aikio

    2009-07-01

    Full Text Available Statistical properties of Joule heating rate, electric field and conductances in the high latitude ionosphere are studied by a unique one-month measurement made by the EISCAT incoherent scatter radar in Tromsø (66.6 cgmlat from 6 March to 6 April 2006. The data are from the same season (close to vernal equinox and from similar sunspot conditions (about 1.5 years before the sunspot minimum providing an excellent set of data to study the MLT and Kp dependence of parameters with high temporal and spatial resolution. All the parameters show a clear MLT variation, which is different for low and high Kp conditions. Our results indicate that the response of morning sector conductances and conductance ratios to increased magnetic activity is stronger than that of the evening sector. The co-location of Pedersen conductance maximum and electric field maximum in the morning sector produces the largest Joule heating rates 03–05 MLT for Kp≥3. In the evening sector, a smaller maximum occurs at 18 MLT. Minimum Joule heating rates in the nightside are statistically observed at 23 MLT, which is the location of the electric Harang discontinuity. An important outcome of the paper are the fitted functions for the Joule heating rate as a function of electric field magnitude, separately for four MLT sectors and two activity levels (Kp<3 and Kp≥3. In addition to the squared electric field, the fit includes a linear term to study the possible anticorrelation or correlation between electric field and conductance. In the midday sector, positive correlation is found as well as in the morning sector for the high activity case. In the midnight and evening sectors, anticorrelation between electric field and conductance is obtained, i.e. high electric fields are associated with low conductances. This is expected to occur in the return current regions adjacent to auroral arcs as a result of ionosphere-magnetosphere coupling, as discussed by Aikio et al. (2004 In

  4. Modeling properties of chromospheric evaporation driven by thermal conduction fronts from reconnection shocks

    Energy Technology Data Exchange (ETDEWEB)

    Brannon, Sean; Longcope, Dana [Department of Physics, Montana State University, Bozeman, MT 59717 (United States)

    2014-09-01

    Magnetic reconnection in the corona results in contracting flare loops, releasing energy into plasma heating and shocks. The hydrodynamic shocks produced in this manner drive thermal conduction fronts (TCFs) which transport energy into the chromosphere and drive upflows (evaporation) and downflows (condensation) in the cooler, denser footpoint plasma. Observations have revealed that certain properties of the transition point between evaporation and condensation (the 'flow reversal point' or FRP), such as temperature and velocity-temperature derivative at the FRP, vary between different flares. These properties may provide a diagnostic tool to determine parameters of the coronal energy release mechanism and the loop atmosphere. In this study, we develop a one-dimensional hydrodynamical flare loop model with a simplified three-region atmosphere (chromosphere/transition region/corona), with TCFs initiated by shocks introduced in the corona. We investigate the effect of two different flare loop parameters (post-shock temperature and transition region temperature ratio) on the FRP properties. We find that both of the evaporation characteristics have scaling-law relationships to the varied flare parameters, and we report the scaling exponents for our model. This provides a means of using spectroscopic observations of the chromosphere as quantitative diagnostics of flare energy release in the corona.

  5. Effect of ionic conductivity of zirconia electrolytes on polarization properties of various electrodes in SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Masahiro; Uchida, Hiroyuki; Yoshida, Manabu [Yamanashi Univ., Kofu (Japan)

    1996-12-31

    Solid oxide fuel cells (SOFCs) have been intensively investigated because, in principle, their energy conversion efficiency is fairly high. Lowering the operating temperature of SOFCs from 1000{degrees}C to around 800{degrees}C is desirable for reducing serious problems such as physical and chemical degradation of the constructing materials. The object of a series of the studies is to find a clue for achieving higher electrode performances at a low operating temperature than those of the present level. Although the polarization loss at electrodes can be reduced by using mixed-conducting ceria electrolytes, or introducing the mixed-conducting (reduced zirconia or ceria) laver on the conventional zirconia electrolyte surface, no reports are available on the effect of such an ionic conductivity of electrolytes on electrode polarizations. High ionic conductivity of the electrolyte, of course, reduces the ohmic loss. However, we have found that the IR-free polarization of a platinum anode attached to zirconia electrolytes is greatly influenced by the ionic conductivity, {sigma}{sub ion}, of the electrolytes used. The higher the {sigma}{sub ion}, the higher the exchange current density, j{sub 0}, for the Pt anode in H{sub 2} at 800 {approximately} 1000{degrees}C. It was indicated that the H{sub 2} oxidation reaction rate was controlled by the supply rate of oxide ions through the Pt/zirconia interface which is proportional to the {sigma}{sub ion}. Recently, we have proposed a new concept of the catalyzed-reaction layers which realizes both high-performances of anodes and cathodes for medium-temperature operating SOFCs. We present the interesting dependence of the polarization properties of various electrodes (the SDC anodes with and without Ru microcatalysts, Pt cathode, La(Sr)MnO{sub 3} cathodes with and without Pt microcatalysts) on the {sigma}{sub ion} of various zirconia electrolytes at 800 {approximately} 1000{degrees}C.

  6. Effects of silicon, copper and iron on static and dynamic properties of alloy 206 (aluminum-copper) in semi-solids produced by the SEED process

    Science.gov (United States)

    Lemieux, Alain

    The advantages of producing metal parts by rheocasting are generally recognised for common foundry alloys of Al-Si. However, other more performing alloys in terms of mechanical properties could have a great interest in specialized applications in the automotive industry, while remaining competitive in the forming. Indeed, the growing demand for more competitive products requires the development of new alloys better suited to semi-solid processes. Among others, Al-Cu alloys of the 2XX series are known for their superior mechanical strength. However, in the past, 2XX alloys were never candidates for pressure die casting. The main reason is their propensity to hot tearing. Semi-solid processes provide better conditions for molding with the rheological behavior of dough and molding temperatures lower reducing this type of defect. In the initial phase, this research has studied factors that reduce hot tearing susceptibility of castings produced by semi-solid SEED of alloy 206. Subsequently, a comparative study on the tensile properties and fatigue was performed on four variants of the alloy 206. The results of tensile strength and fatigue were compared with the specifications for applications in the automotive industry and also to other competing processes and alloys. During this study, several metallurgical aspects were analyzed. The following main points have been validated: i) the main effects of compositional variations of silicon, iron and copper alloy Al-Cu (206) on the mechanical properties, and ii) certain relationships between the mechanism of hot cracking and the solidification rate in semi-solid. Parts produced from the semi-solid paste coming from the SEED process combined with modified 206 alloys have been successfully molded and achieved superior mechanical properties than the requirements of the automotive industry. The fatigue properties of the two best modified 206 alloys were higher than those of A357 alloy castings and are close to those of the

  7. Wood hemicellulose/chitosan-based semi-interpenetrating network hydrogels : mechanical swelling and controlled drug release properties

    Science.gov (United States)

    Ahmet M. Karaaslan; Mandla A. Tshabalala; Gisela Buschle-Diller

    2010-01-01

    The cell wall of most plant biomass from forest and agricultural resources consists of three major polymers, cellulose, hemicellulose, and lignin. Of these, hemicelluloses have gained increasing attention as sustainable raw materials. In this study, novel pH-sensitive semi-IPN hydrogels based on hemicelluloses and chitosan were prepared using glutaraldehyde as the...

  8. Semi-Interpenetrating polymer network hydrogels based on aspen hemicellulose and chitosan: Effect of crosslinking sequence on hydrogel properties

    Science.gov (United States)

    Muzaffer Ahmet Karaaslan; Mandla A. Tshabalala; Gisela Buschle-Diller

    2012-01-01

    Semi-interpenetrating network hydrogel films were prepared using hemicellulose and chemically crosslinked chitosan. Hemicellulose was extracted from aspen by using a novel alkaline treatment and characterized by HPSEC, and consisted of a mixture of high and low molecular weight polymeric fractions. HPLC analysis of the acid hydrolysate of the hemicellulose showed that...

  9. Generation of conductivity through transfer charge properties, for polyesters and polyamides with characteristic functional groups

    Science.gov (United States)

    Gonzalez, Carmen; Tagle, Luis Hernan; Terraza, Claudio A.; Barriga, Andres; Cabrera, A. L.; Volkmann, Ulrich G.

    2011-03-01

    Electro-optic properties of σ -conjugated polymers, as polysilylene; are associated with electron conjugation in the silicon atom, which allows a significant delocalization of electrons along of the chain. Thus, the conductivity is intimately connected to the mobility of charge carriers, which in turn depends on the structure and morphology of the system. We report the characterization of polyesters (PEFs) and polyamides (PAFs). Film thicknesses were obtained by ellipsometry. The vibration frequencies of the groups were determined by FT-IR and corroborated by Raman spectroscopy. Structural information was obtained from X-Ray diffraction (XRD). The structural and surface morphology were studied by scanning electron microscope (SEM). Electrical conductivity of the polymers was measured before and after exposure to iodine vapor, for films of different thicknesses. Morphological differentiation was studied by energy dispersive microscopy (EDX), showing a regular distribution of iodine within the polymer. Preliminary conductivity measurements showed adverse effects when oxidation of the polymer films is induced These effects are related to a certain grade of disorder within the system

  10. Chitosan nanocomposite films: enhanced electrical conductivity, thermal stability, and mechanical properties.

    Science.gov (United States)

    Marroquin, Jason B; Rhee, K Y; Park, S J

    2013-02-15

    A novel, high-performance Fe(3)O(4)/MWNT/Chitosan nanocomposite has been prepared by a simple solution evaporation method. A significant synergistic effect of Fe(3)O(4) and MWNT provided enhanced electrical conductivity, mechanical properties, and thermal stability on the nanocomposites. A 5% (wt) loading of Fe(3)O(4)/MWNT in the nanocomposite increased conductivity from 5.34×10(-5) S/m to 1.49×10(-2) S/m compared to 5% (wt) MWNT loadings. The Fe(3)O(4)/MWNT/Chitosan films also exhibited increases in tensile strength and modulus of 70% and 155%, respectively. The integral procedure decomposition temperature (IPDT) was enhanced from 501 °C to 568 °C. These effects resulted from a number of factors: generation of a greater number of conductive channels through interactions between MWNT and Fe(3)O(4) surfaces, a higher relative crystallinity, the antiplasticizing effects of Fe(3)O(4), a restricted mobility and hindrance of depolymerization of the Chitosan chain segments, as well as uniform distribution, improved dispersion, and strong interfacial adhesion between the MWNT and Chitosan matrix. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Investigation of thermal conductivity and rheological properties of nanofluids containing graphene nanoplatelets

    Science.gov (United States)

    2014-01-01

    In the present study, stable homogeneous graphene nanoplatelet (GNP) nanofluids were prepared without any surfactant by high-power ultrasonic (probe) dispersion of GNPs in distilled water. The concentrations of nanofluids were maintained at 0.025, 0.05, 0.075, and 0.1 wt.% for three different specific surface areas of 300, 500, and 750 m2/g. Transmission electron microscopy image shows that the suspensions are homogeneous and most of the materials have been well dispersed. The stability of nanofluid was investigated using a UV-visible spectrophotometer in a time span of 600 h, and zeta potential after dispersion had been investigated to elucidate its role on dispersion characteristics. The rheological properties of GNP nanofluids approach Newtonian and non-Newtonian behaviors where viscosity decreases linearly with the rise of temperature. The thermal conductivity results show that the dispersed nanoparticles can always enhance the thermal conductivity of the base fluid, and the highest enhancement was obtained to be 27.64% in the concentration of 0.1 wt.% of GNPs with a specific surface area of 750 m2/g. Electrical conductivity of the GNP nanofluids shows a significant enhancement by dispersion of GNPs in distilled water. This novel type of nanofluids shows outstanding potential for replacements as advanced heat transfer fluids in medium temperature applications including solar collectors and heat exchanger systems. PMID:24410867

  12. Pyroelectric properties and electrical conductivity in samarium doped BiFeO 3 ceramics

    KAUST Repository

    Yao, Yingbang

    2012-06-01

    Samarium (Sm 3+) doped BiFeO 3 (BFO) ceramics were prepared by a modified solid-state-reaction method which adopted a rapid heating as well as cooling during the sintering process. The pyroelectric coefficient increased from 93 to 137 μC/m 2 K as the Sm 3+ doping level increased from 1 mol% to 8 mol%. Temperature dependence of the pyroelectric coefficient showed an abrupt decrease above 80 °C in all samples, which was associated with the increase of electrical conductivity with temperature. This electrical conduction was attributed to oxygen vacancy existing in the samples. An activation energy of ∼0.7 eV for the conduction process was found to be irrespective of the Sm 3+ doping level. On the other hand, the magnetic Néel temperature (T N) decreased with increasing Sm 3+ doping level. On the basis of our results, the effects of Sm doping level on the pyroelectric and electrical properties of the BFO were revealed. © 2011 Elsevier Ltd. All rights reserved.

  13. High temperature conductance mapping for correlation of electrical properties with micron-sized chemical and microstructural features

    DEFF Research Database (Denmark)

    Hansen, Karin Vels; Norrman, Kion; Jacobsen, Torben

    2016-01-01

    High temperature AC conductance mapping is a scanning probe technique for resolving local electrical properties in microscopic areas. It is especially suited for detecting poorly conducting phases and for ionically conducting materials such as those used in solid oxide electrochemical cells...

  14. Evaluation of thermal physical properties for fast reactor fuels. Melting point and thermal conductivities

    International Nuclear Information System (INIS)

    Kato, Masato; Morimoto, Kyoichi; Komeno, Akira; Nakamichi, Shinya; Kashimura, Motoaki; Abe, Tomoyuki; Uno, Hiroki; Ogasawara, Masahiro; Tamura, Tetsuya; Sugata, Hirotada; Sunaoshi, Takeo; Shibata, Kazuya

    2006-10-01

    Japan Atomic Energy Agency has developed a fast breeder reactor (FBR), and plutonium and uranium mixed oxide (MOX) having low density and 20-30%Pu content has used as a fuel of the FBR, Monju. In plutonium, Americium has been accumulated during long-term storage, and Am content will be increasing up to 2-3% in the MOX. It is essential to evaluate the influence of Am content on physical properties of MOX on the development of FBR in the future. In this study melting points and thermal conductivities which are important data on the fuel design were measured systematically in wide range of composition, and the effects of Am accumulated were evaluated. The solidus temperatures of MOX were measured as a function of Pu content, oxygen to metal ratio (O/M) and Am content using thermal arrest technique. The sample was sealed in a tungsten capsule in vacuum for measuring solidus temperature. In the measurements of MOX with Pu content of more than 30%, a rhenium inner capsule was used to prevent the reaction between MOX and tungsten. In the results, it was confirmed that the melting points of MOX decrease with as an increase of Pu content and increase slightly with a decrease of O/M ratio. The effect of Am content on the fuel design was negligible small in the range of Am content up to 3%. Thermal conductivities of MOX were evaluated from thermal diffusivity measured by laser flash method and heat capacity calculated by Neumann- Kopp's law. The thermal conductivity of MOX decreased slightly in the temperature of less than 1173K with increasing Am content. The effect of Am accumulated in long-term storage fuel was evaluated from melting points and thermal conductivities measured in this study. It is concluded that the increase of Am in the fuel barely affect the fuel design in the range of less than 3%Am content. (author)

  15. Wireless communication with implanted medical devices using the conductive properties of the body.

    Science.gov (United States)

    Ferguson, John E; Redish, A David

    2011-07-01

    Many medical devices that are implanted in the body use wires or wireless radiofrequency telemetry to communicate with circuitry outside the body. However, the wires are a common source of surgical complications, including breakage, infection and electrical noise. In addition, radiofrequency telemetry requires large amounts of power and results in low-efficiency transmission through biological tissue. As an alternative, the conductive properties of the body can be used to enable wireless communication with implanted devices. In this article, several methods of intrabody communication are described and compared. In addition to reducing the complications that occur with current implantable medical devices, intrabody communication can enable novel types of miniature devices for research and clinical applications.

  16. Temperature Dependence on Structural, Tribological, and Electrical Properties of Sputtered Conductive Carbon Thin Films

    International Nuclear Information System (INIS)

    Park, Yong Seob; Hong, Byung You; Cho, Sang Jin; Boo, Jin Hyo

    2011-01-01

    Conductive carbon films were prepared at room temperature by unbalanced magnetron sputtering (UBMS) on silicon substrates using argon (Ar) gas, and the effects of post-annealing temperature on the structural, tribological, and electrical properties of carbon films were investigated. Films were annealed at temperatures ranging from 400 .deg. C to 700 .deg. C in increments of 100 .deg. C using a rapid thermal annealing method by vacuum furnace in vacuum ambient. The increase of annealing temperature contributed to the increase of the ordering and formation of aromatic rings in the carbon film. Consequently, with increasing annealing temperature the tribological properties of sputtered carbon films are deteriorated while the resistivity of carbon films significantly decreased from 4.5 x 10 -3 to 1.0 x 10 -6 Ω-cm and carrier concentration as well as mobility increased, respectively. This behavior can be explained by the increase of sp 2 bonding fraction and ordering sp 2 clusters in the carbon networks caused by increasing annealing temperature

  17. Effect of lanthanum substitution on dielectric relaxation, impedance response, conducting and magnetic properties of strontium hexaferrite

    Energy Technology Data Exchange (ETDEWEB)

    Want, Basharat, E-mail: bawant@kashmiruniversity.ac.in; Bhat, Bilal Hamid; Ahmad, Bhat Zahoor

    2015-04-05

    Highlights: • The substitution of La affects the dielectric and magnetic properties of strontium hexaferrite. • The electric behaviour of the compound follows the Koop’s phenomenological theory. • The impedance study shows the role of grain boundaries to the electric properties of the compound. • The substitution of La to strontium hexaferrite reduces the resistive nature of grain boundaries. - Abstract: Lanthanum strontium hexaferrite Sr{sub 1−x}La{sub x}Fe{sub 12}O{sub 19} (x = 0, 0.08, 0.13 , 0.18) has been successfully synthesized by using citrate-precursor method and characterized by different techniques. The X-ray diffraction results revealed that the sample is crystalline in nature and is of single phase with the space group P63/mmc. The dielectric, conducting and impedance related studies have been carried out as a function of frequency and concentration of lanthanum in the frequency ranges of 20 Hz–3 MHz. Impedance studies were performed in the frequency domain to distinguish between bulk and grain boundary contributions of the material to the overall dielectric response. The electric response of the material was also modeled by an equivalent circuit and different circuit parameters were calculated. Magnetic characterization of the material was also performed and the effect of lanthanum concentration was studied. The hysteresis loop obtained from the magnetometer showed that with the increase of lanthanum concentration, the saturation magnetisation decreases while as coercivity increases.

  18. Structural and physical properties of transparent conducting, amorphous Zn-doped SnO2 films

    Science.gov (United States)

    Zhu, Q.; Ma, Q.; Buchholz, D. B.; Chang, R. P. H.; Bedzyk, M. J.; Mason, T. O.

    2014-01-01

    The structural and physical properties of conducting amorphous Zn-doped SnO2 (a-ZTO) films, prepared by pulsed laser deposition, were investigated as functions of oxygen deposition pressure (pO2), composition, and thermal annealing. X-ray scattering and X-ray absorption spectroscopy measurements reveal that at higher pO2, the a-ZTO films are highly transparent and have a structural framework similar to that found in crystalline (c-), rutile SnO2 in which the Sn4+ ion is octahedrally coordinated by 6 O2- ions. The Sn4+ ion in these films however has a coordination number (CN) smaller by 2%-3% than that in c-SnO2, indicating the presence of oxygen vacancies, which are the likely source of charge carriers. At lower pO2, the a-ZTO films show a brownish tint and contain some 4-fold coordinated Sn2+ ions. Under no circumstances is the CN around the Zn2+ ion larger than 4, and the Zn-O bond is shorter than the Sn-O bond by 0.07 Å. The addition of Zn has no impact on the electroneutrality but improves significantly the thermal stability of the films. Structural changes due to pO2, composition, and thermal annealing account well for the changes in the physical properties of a-ZTO films.

  19. Electrical and optical properties of Zn–In–Sn–O transparent conducting thin films

    International Nuclear Information System (INIS)

    Carreras, Paz; Antony, Aldrin; Rojas, Fredy; Bertomeu, Joan

    2011-01-01

    Indium tin oxide (ITO) is one of the widely used transparent conductive oxides (TCO) for application as transparent electrode in thin film silicon solar cells or thin film transistors owing to its low resistivity and high transparency. Nevertheless, indium is a scarce and expensive element and ITO films require high deposition temperature to achieve good electrical and optical properties. On the other hand, although not competing as ITO, doped Zinc Oxide (ZnO) is a promising and cheaper alternative. Therefore, our strategy has been to deposit ITO and ZnO multicomponent thin films at room temperature by radiofrequency (RF) magnetron co-sputtering in order to achieve TCOs with reduced indium content. Thin films of the quaternary system Zn–In–Sn–O (ZITO) with improved electrical and optical properties have been achieved. The samples were deposited by applying different RF powers to ZnO target while keeping a constant RF power to ITO target. This led to ZITO films with zinc content ratio varying between 0 and 67%. The optical, electrical and morphological properties have been thoroughly studied. The film composition was analysed by X-ray Photoelectron Spectroscopy. The films with 17% zinc content ratio showed the lowest resistivity (6.6 × 10 −4 Ω cm) and the highest transmittance (above 80% in the visible range). Though X-ray Diffraction studies showed amorphous nature for the films, using High Resolution Transmission Electron Microscopy we found that the microstructure of the films consisted of nanometric crystals embedded in a compact amorphous matrix. The effect of post deposition annealing on the films in both reducing and oxidizing atmospheres were studied. The changes were found to strongly depend on the zinc content ratio in the films.

  20. Dynamics investigation of change of freshness and properties of new types of semi-smoked sausages during storage

    Directory of Open Access Journals (Sweden)

    Ірина Іллівна Маркович

    2015-03-01

    Full Text Available Stable quality of sausages during storage is achieved through improving processes, modes and storage conditions, use of various food additives and antioxidants that will positively affect the inhibition of hydrolytic and oxidative changes in lipids. In production technology of semi- smoked sausages we propose the use of plant material – flour of sprouted and not sprouted lentil, and to lengthen shelf life – thyme and juniper 

  1. Measurement of the conductance properties of single organic molecules using gold nanoparticles

    Science.gov (United States)

    Gordin, Yoav

    In this work we describe the development and application of a new method for the electrical conductance measurement of single molecules. The issue of reliable theoretical modeling of molecular electronic transport is still very much in debate. The experimental methods used in the field are difficult to realize and interpret; most have very low yield, preventing proper statistical analysis and many have problems in the researchers' ability to characterize the system properly. We address this issue by using self assembly of gold nanoparticle-molecule-gold nanoparticle objects called dimers. This method allows fabrication of molecular junctions with greater ease; moreover it allows individual characterization of the various elements of the junction, removing much of the uncertainties that exist in this kind of measurements. We make use of home grown gold nanoparticles with a few tens of nanometer diameter to form the hybrid dimers. The dimers are large enough to connect between electrodes fabricated using electron beam lithography and to measure the electric properties of the molecule. We have invested significant effort in the characterization of the system, ensuring that the dimers are indeed bridged by the molecules, and that the chances that more than a single molecule exists in a dimer are negligibly small. We have made measurements on single gold nanoparticles, to characterize their properties separately from those of the molecule. These measurements have allowed us to observe single electron transistor (SET) behavior, resulting from the requirement that electrons charge the nanoparticle during transport. We have shown that the energy associated with this charging scales with nanoparticle size as expected. We have performed measurements on single organic molecules, showing that there is a very strong influence of molecular conjugation (the way electronic orbitals are spread along the molecular backbone) on its conductance. The molecules with broken conjugation

  2. The thermal properties of a carbon nanotube-enriched epoxy: Thermal conductivity, curing, and degradation kinetics

    KAUST Repository

    Ventura, Isaac Aguilar

    2013-05-31

    Multiwalled carbon nanotube-enriched epoxy polymers were prepared by solvent evaporation based on a commercially available epoxy system and functionalized multiwalled carbon nanotubes (COOH-MWCNTs). Three weight ratio configurations (0.05, 0.5, and 1.0 wt %) of COOH-MWCNTs were considered and compared with neat epoxy and ethanol-treated epoxy to investigate the effects of nano enrichment and processing. Here, the thermal properties of the epoxy polymers, including curing kinetics, thermal conductivity, and degradation kinetics were studied. Introducing the MWCNTs increased the curing activation energy as revealed by differential scanning calorimetry. The final thermal conductivity of the 0.5 and 1.0 wt % MWCNT-enriched epoxy samples measured by laser flash technique increased by up to 15% compared with the neat material. The activation energy of the degradation process, investigated by thermogravimetric analysis, was found to increase with increasing CNT content, suggesting that the addition of MWCNTs improved the thermal stability of the epoxy polymers. © 2013 Wiley Periodicals, Inc.

  3. Highly Porous, Rigid-Rod Polyamide Aerogels with Superior Mechanical Properties and Unusually High Thermal Conductivity.

    Science.gov (United States)

    Williams, Jarrod C; Nguyen, Baochau N; McCorkle, Linda; Scheiman, Daniel; Griffin, Justin S; Steiner, Stephen A; Meador, Mary Ann B

    2017-01-18

    We report here the fabrication of polyamide aerogels composed of poly-p-phenylene-terephthalamide, the same backbone chemistry as DuPont's Kevlar. The all-para-substituted polymers gel without the use of cross-linker and maintain their shape during processing-an improvement over the meta-substituted cross-linked polyamide aerogels reported previously. Solutions containing calcium chloride (CaCl 2 ) and para-phenylenediamine (pPDA) in N-methylpyrrolidinone (NMP) at low temperature are reacted with terephthaloyl chloride (TPC). Polymerization proceeds over the course of 5 min resulting in gelation. Removal of the reaction solvent via solvent exchange followed by extraction with supercritical carbon dioxide provides aerogels with densities ranging from 0.1 to 0.3 g/cm 3 , depending on the concentration of calcium chloride, the formulated number of repeat units, n, and the concentration of polymer in the reaction mixture. These variables were assessed in a statistical experimental study to understand their effects on the properties of the aerogels. Aerogels made using at least 30 wt % CaCl 2 had the best strength when compared to aerogels of similar density. Furthermore, aerogels made using 30 wt % CaCl 2 exhibited the lowest shrinkage when aged at elevated temperatures. Notably, whereas most aerogel materials are highly insulating (thermal conductivities of 10-30 mW/m K), the polyamide aerogels produced here exhibit remarkably high thermal conductivities (50-80 mW/(m K)) at the same densities as other inorganic and polymer aerogels. These high thermal conductivities are attributed to efficient phonon transport by the rigid-rod polymer backbone. In conjunction with their low cost, ease of fabrication with respect to other polymer aerogels, low densities, and high mass-normalized strength and stiffness properties, these aerogels are uniquely valuable for applications such as lightweighting in consumer electronics, automobiles, and aerospace where weight reduction is

  4. Pulsed EM Field Response of a Thin, High-Contrast, Finely Layered Structure With Dielectric and Conductive Properties

    NARCIS (Netherlands)

    De Hoop, A.T.; Jiang, L.

    2009-01-01

    The response of a thin, high-contrast, finely layered structure with dielectric and conductive properties to an incident, pulsed, electromagnetic field is investigated theoretically. The fine layering causes the standard spatial discretization techniques to solve Maxwell's equations numerically to

  5. DC conductivity and magnetic properties of piezoelectric–piezomagnetic composite system

    International Nuclear Information System (INIS)

    Hemeda, O.M.; Tawfik, A.; A-Al-Sharif; Amer, M.A.; Kamal, B.M.; El Refaay, D.E.; Bououdina, M.

    2012-01-01

    A series of composites (1−x) (Ni 0.8 Zn 0.2 Fe 2 O 4 )+x (BaTiO 3 ), where x=0%, 20%, 40%, 60%, 80% and 100% BT content, have been prepared by the standard ceramic technique, then sintered at 1200 °C for 8 h. X-ray diffraction analysis shows that the prepared composites consist of two phases, ferrimagnetic and ferroelectric. DC electrical resistivity, thermoelectric power, charge carriers concentration and charge carrier mobility have been studied at different temperatures. It was found that the DC electrical conductivity increases with increasing BT content. The values of the thermoelectric power were positive and negative for the composites indicating that there are two conduction mechanisms, hopping and band conduction, respectively. Using the values of DC electrical conductivity and thermoelectric power, the values of charge carrier mobility and the charge carrier concentration were calculated. Magnetic measurements (hysteresis loop and magnetic permeability) show that the magnetization decreases by increasing BT content. M–H loop of pure Ni 0.6 Zn 0.4 Fe 2 O 4 composite indicates that it is paramagnetic at room temperature and that the magnetization is diluted by increasing the BT content in the composite system. The value of magnetoelectric coefficient for the composites decreases by increasing BT content for all the compositions except for 40% BT content, which may be due to the low resistivity of magnetic phase compared with the BT phase that causes a leakage of induced charges on the piezoelectric phase. Since both ferroelectric and magnetic phases preserve their basic properties in the bulk composite, the present BT–NZF composite are potential candidates for applications as pollution sensors and electromagnetic waves. - Highlights: ► Studied composite has a high magnetoelectric coefficient compared with other composites. ► A p–n transition is observed for the composite with 80% BT and 100% BT content. ► Ni-ferrite can lead to a strong shift

  6. DC conductivity and magnetic properties of piezoelectric-piezomagnetic composite system

    Energy Technology Data Exchange (ETDEWEB)

    Hemeda, O.M., E-mail: omhemeda@yahoo.co.uk [Tanta University, Faculty of Science, Physics Department (Egypt); Taif University, Faculty of Science, Physics Department (Saudi Arabia); Tawfik, A. [Taif University, Faculty of Science, Physics Department (Saudi Arabia); A-Al-Sharif [Moata University, Faculty of Science, Physics Department (Jordan); Amer, M.A. [Taif University, Faculty of Science, Physics Department (Saudi Arabia); Kamal, B.M.; El Refaay, D.E. [Suez Canal University, Faculty of Science, Physics Department (Egypt); Bououdina, M. [Nanotechnology Centre, College of Science, University of Bahrain, PO Box 32038 (Bahrain); Department of Physics, College of Science, University of Bahrain, PO Box 32038 (Bahrain)

    2012-11-15

    A series of composites (1-x) (Ni{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4})+x (BaTiO{sub 3}), where x=0%, 20%, 40%, 60%, 80% and 100% BT content, have been prepared by the standard ceramic technique, then sintered at 1200 Degree-Sign C for 8 h. X-ray diffraction analysis shows that the prepared composites consist of two phases, ferrimagnetic and ferroelectric. DC electrical resistivity, thermoelectric power, charge carriers concentration and charge carrier mobility have been studied at different temperatures. It was found that the DC electrical conductivity increases with increasing BT content. The values of the thermoelectric power were positive and negative for the composites indicating that there are two conduction mechanisms, hopping and band conduction, respectively. Using the values of DC electrical conductivity and thermoelectric power, the values of charge carrier mobility and the charge carrier concentration were calculated. Magnetic measurements (hysteresis loop and magnetic permeability) show that the magnetization decreases by increasing BT content. M-H loop of pure Ni{sub 0.6} Zn{sub 0.4} Fe{sub 2}O{sub 4} composite indicates that it is paramagnetic at room temperature and that the magnetization is diluted by increasing the BT content in the composite system. The value of magnetoelectric coefficient for the composites decreases by increasing BT content for all the compositions except for 40% BT content, which may be due to the low resistivity of magnetic phase compared with the BT phase that causes a leakage of induced charges on the piezoelectric phase. Since both ferroelectric and magnetic phases preserve their basic properties in the bulk composite, the present BT-NZF composite are potential candidates for applications as pollution sensors and electromagnetic waves. - Highlights: Black-Right-Pointing-Pointer Studied composite has a high magnetoelectric coefficient compared with other composites. Black-Right-Pointing-Pointer A p-n transition is observed

  7. The capability of graphene on improving the electrical conductivity and anti-corrosion properties of Polyurethane coatings

    Science.gov (United States)

    Tong, Yao; Bohm, Siva; Song, Mo

    2017-12-01

    Graphite and graphene particles were used to reinforce the electrical conductivity and anti-corrosion properties of polyurethane (PU) coatings. The effect of graphite and graphene were compared. Hybrid filler using carbon nanotube was adopted as well and the performance in electrical conductivity was much superior to single filler system. At the same filler loading, the electrical conductivity of hybrid filler system was significantly higher than single filler system (0.77 S/m at 5 wt% while single filler system was not conductive). The conductive mechanism was revealed. In terms of anti-corrosion properties, the coatings with low filler loading had better anti-corrosion properties. The resistance values obtained from EIS (Electrochemical Impedance Spectroscopy) and four point probe method were compared and discussed.

  8. Metallic and semi-conducting resistivity behaviour of La0.7Ca0.3- x K x MnO3 ( x = 0.05, 0.1) manganites

    Science.gov (United States)

    Varshney, Dinesh; Dodiya, Neha

    2015-12-01

    The temperature dependence of electrical resistivity, ρ, of ceramic La0.7Ca0.3- x K x MnO3 ( x = 0.05, 0.1) is investigated in metallic and semi-conducting phase. The metallic resistivity is attributed to be caused by electron-phonon, electron-electron and electron-magnon scattering. Substitutions affect average mass and ionic radii of A-site resulting in an increase in Debye temperature θ D attributed to hardening of lattice with K doping. The optical phonon modes shift gradually to lower mode frequencies leading to phonon softening. Estimated resistivity compared with reported metallic resistivity, accordingly ρ diff. = [ ρ exp. - { ρ 0 + ρ e-ph (= ρ ac + ρ op)}], infers electron-electron and electron-magnon dependence over most of the temperature range. Semi-conducting nature is discussed with variable range hopping and small polaron conduction model. The decrease in activation energies and increase in density of states at the Fermi level with enhanced Ca doping is consistently explained by cationic disorder and Mn valence.

  9. Molecular mechanics of DNA bricks: in situ structure, mechanical properties and ionic conductivity

    International Nuclear Information System (INIS)

    Slone, Scott Michael; Li, Chen-Yu; Aksimentiev, Aleksei; Yoo, Jejoong

    2016-01-01

    The DNA bricks method exploits self-assembly of short DNA fragments to produce custom three-dimensional objects with subnanometer precision. In contrast to DNA origami, the DNA brick method permits a variety of different structures to be realized using the same library of DNA strands. As a consequence of their design, however, assembled DNA brick structures have fewer interhelical connections in comparison to equivalent DNA origami structures. Although the overall shape of the DNA brick objects has been characterized and found to conform to the features of the target designs, the microscopic properties of DNA brick objects remain yet to be determined. Here, we use the all-atom molecular dynamics method to directly compare the structure, mechanical properties and ionic conductivity of DNA brick and DNA origami structures different only by internal connectivity of their consistituent DNA strands. In comparison to equivalent DNA origami structures, the DNA brick structures are found to be less rigid and less dense and have a larger cross-section area normal to the DNA helix direction. At the microscopic level, the junction in the DNA brick structures are found to be right-handed, similar to the structure of individual Holliday junctions (HJ) in solution, which contrasts with the left-handed structure of HJ in DNA origami. Subject to external electric field, a DNA brick plate is more leaky to ions than an equivalent DNA origami plate because of its lower density and larger cross-section area. Overall, our results indicate that the structures produced by the DNA brick method are fairly similar in their overall appearance to those created by the DNA origami method but are more compliant when subject to external forces, which likely is a consequence of their single crossover design. (paper)

  10. Gold-ionic liquid nanofluids with preferably tribological properties and thermal conductivity

    Directory of Open Access Journals (Sweden)

    Wang Baogang

    2011-01-01

    Full Text Available Abstract Gold/1-butyl-3-methylimidazolium hexafluorophosphate (Au/[Bmim][PF6] nanofluids containing different stabilizing agents were fabricated by a facile one-step chemical reduction method, of which the nanofluids stabilized by cetyltrimethylammonium bromide (CTABr exhibited ultrahighly thermodynamic stability. The transmission electron microscopy, UV-visible absorption, Fourier transform infrared, and X-ray photoelectron characterizations were conducted to reveal the stable mechanism. Then, the tribological properties of these ionic liquid (IL-based gold nanofluids were first investigated in more detail. In comparison with pure [Bmim][PF6] and the nanofluids possessing poor stability, the nanofluids with high stability exhibited much better friction-reduction and anti-wear properties. For instance, the friction coefficient and wear volume lubricated by the nanofluid with rather low volumetric concentration (1.02 × 10-3% stabilized by CTABr under 800 N are 13.8 and 45.4% lower than that of pure [Bmim][PF6], confirming that soft Au nanoparticles (Au NPs also can be excellent additives for high performance lubricants especially under high loads. Moreover, the thermal conductivity (TC of the stable nanofluids with three volumetric fraction (2.55 × 10-4, 5.1 × 10-4, and 1.02 × 10-3% was also measured by a transient hot wire method as a function of temperature (33 to 81°C. The results indicate that the TC of the nanofluid (1.02 × 10-3% is 13.1% higher than that of [Bmim][PF6] at 81°C but no obvious variation at 33°C. The conspicuously temperature-dependent and greatly enhanced TC of Au/[Bmim][PF6] nanofluids stabilized by CTABr could be attributed to micro-convection caused by the Brownian motion of Au NPs. Our results should open new avenues to utilize Au NPs and ILs in tribology and the high-temperature heat transfer field.

  11. Electrical conductivity and transport properties of cement-based materials measured by impedance spectroscopy

    Science.gov (United States)

    Shane, John David

    The use of Impedance Spectroscopy (IS) as a tool to evaluate the electrical and transport properties of cement-based materials was critically evaluated. Emphasis was placed on determining the efficacy of IS by applying it as a tool to investigate several families of cement-based materials. Also, the functional aspects of electroding and null corrections were also addressed. The technique was found to be advantageous for these analyses, especially as a non-destructive, in-situ, rapid test. Moreover, key insights were gained into several cement-based systems (e.g., cement mortars and oil-well grouts) as well as the effect that certain testing techniques can have on materials (e.g., the rapid chloride permeability test). However, some limitations of IS were identified. For instance, improper electroding of samples can lead to erroneous results and incorrect interpretations for both two-point and multi-point measurements. This is an area of great importance, but it has received very little attention in the literature. Although the analysis of cement/electrode techniques is in its infancy, much progress was made in gaining a full understand of how to properly and reliably connect electrodes to cement-based materials. Through the application of IS to materials such as oil-well grouts, cement mortars and concretes, a great deal of valuable information about the effectiveness of IS has been gained. Oil-well cementing is somewhat limited by the inability to make measurements in the well-bore. By applying IS to oil-well grouts in a laboratory environment, it was demonstrated that IS is a viable technique with which to test the electrical and transport properties of these materials in-situ. Also, IS was shown to have the ability to measure the electrical conductivity of cement mortars with such accuracy, that very subtle changes in properties can be monitored and quantified. Through the use of IS and theoretical models, the complex interplay between the interfacial transition

  12. Thermal conductivity and heat transport properties of nitrogen-doped graphene.

    Science.gov (United States)

    Goharshadi, Elaheh K; Mahdizadeh, Sayyed Jalil

    2015-11-01

    In the present study, the thermal conductivity (TC) and heat transport properties of nitrogen doped graphene (N-graphene) were investigated as a function of temperature (107-400K) and N-doped concentration (0.0-7.0%) using equilibrium molecular dynamics simulation based on Green-Kubo method. According to the results, a drastic decline in TC of graphene observed at very low N-doped concentration (0.5 and 1.0%). Substitution of just 1.0% of carbon atoms with nitrogens causes a 77.2, 65.4, 59.2, and 53.7% reduction in TC at 107, 200, 300, and 400K, respectively. The values of TC of N-graphene at different temperatures approach to each other as N-doped concentration increases. The results also indicate that TC of N-graphene is much less sensitive to temperature compared with pristine graphene and the sensitivity decreases as N-doped concentration increases. The phonon-phonon scattering relaxation times and the phonon mean free path of phonons were also calculated. The contribution of high frequency optical phonons for pristine graphene and N-graphene with 7.0% N-doped concentration is 0-2% and 4-8%, respectively. These findings imply that it is potentially feasible to control heat transfer on the nanoscale when designing N-graphene based thermal devices. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Optimization of white organic light emitting diodes based on emitting layer charge carrier conduction properties

    International Nuclear Information System (INIS)

    Baek, H I; Lee, C H

    2008-01-01

    We have fabricated white organic light emitting diodes (OLEDs) with multi-emitting layer (EML) structures in which 4,4'-N,N'-dicarbazole-biphenyl (CBP) layers doped with the phosphorescent dopants fac-tris(2-phenylpyridine) iridium (Ir(ppy) 3 ) and bis(2-(2'-benzo[4,5-a]thienyl)pyridinato-N,C3')iridium(acetylacetonate) (btp 2 Ir(acac)) and the fluorescent dopant 4,4'-bis[2-{4-(N,N-diphenylamino) phenyl}vinyl]biphenyl (DPAVBi) were used as green (G), red (R) and blue (B) EMLs, respectively. A higher efficiency was expected with the R/G/B EML sequence from the hole transport layer interface than with the G/R/B sequence because of the differences in the charge carrier conduction properties of the EMLs doped with phosphorescent dopants and the luminance balance between the phosphorescent and fluorescent emissions. A high efficiency of 18.3 cd A -1 (an external quantum efficiency of 8.5%) at 100 cd m -2 and good colour stability were achieved with the R/G/B EML sequence as expected, with an additional non-doped CBP interlayer used between the G and B EMLs. In addition, the OLED with this sequence was found to have the longest lifetime of the white devices we tested

  14. Optimization of white organic light emitting diodes based on emitting layer charge carrier conduction properties

    Energy Technology Data Exchange (ETDEWEB)

    Baek, H I; Lee, C H [School of Electrical Engineering and Computer Science and Inter-University Semiconductor Research Center, Seoul National University, Seoul 151-744 (Korea, Republic of)], E-mail: hibaek75@snu.ac.kr

    2008-05-21

    We have fabricated white organic light emitting diodes (OLEDs) with multi-emitting layer (EML) structures in which 4,4'-N,N'-dicarbazole-biphenyl (CBP) layers doped with the phosphorescent dopants fac-tris(2-phenylpyridine) iridium (Ir(ppy){sub 3}) and bis(2-(2'-benzo[4,5-a]thienyl)pyridinato-N,C3')iridium(acetylacetonate) (btp{sub 2}Ir(acac)) and the fluorescent dopant 4,4'-bis[2-{l_brace}4-(N,N-diphenylamino) phenyl{r_brace}vinyl]biphenyl (DPAVBi) were used as green (G), red (R) and blue (B) EMLs, respectively. A higher efficiency was expected with the R/G/B EML sequence from the hole transport layer interface than with the G/R/B sequence because of the differences in the charge carrier conduction properties of the EMLs doped with phosphorescent dopants and the luminance balance between the phosphorescent and fluorescent emissions. A high efficiency of 18.3 cd A{sup -1} (an external quantum efficiency of 8.5%) at 100 cd m{sup -2} and good colour stability were achieved with the R/G/B EML sequence as expected, with an additional non-doped CBP interlayer used between the G and B EMLs. In addition, the OLED with this sequence was found to have the longest lifetime of the white devices we tested.

  15. High temperature conductance mapping for correlation of electrical properties with micron-sized chemical and microstructural features

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Karin Vels, E-mail: karv@dtu.dk [Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Norrman, Kion [Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Jacobsen, Torben [Department of Chemistry, Technical University of Denmark, Kemitorvet Building 207, DK-2800 Lyngby (Denmark)

    2016-11-15

    High temperature AC conductance mapping is a scanning probe technique for resolving local electrical properties in microscopic areas. It is especially suited for detecting poorly conducting phases and for ionically conducting materials such as those used in solid oxide electrochemical cells. Secondary silicate phases formed at the edge of lanthanum strontium manganite microelectrodes are used as an example for correlation of chemical, microstructural and electrical properties with a spatial resolution of 1–2 µm to demonstrate the technique. The measurements are performed in situ in a controlled atmosphere high temperature scanning probe microscope at 650 °C in air. - Highlights: • A high temperature SPM technique for conductance measurements was developed. • Two examples from microelectrodes were used for demonstration. • Conductance mapping at 650 °C revealed poorly conducting secondary phases. • The secondary phases could be correlated with microstructure and chemistry.

  16. Improvement of the optoelectronic properties of tin oxide transparent conductive thin films through lanthanum doping

    Energy Technology Data Exchange (ETDEWEB)

    Mrabet, C., E-mail: chokri.mrabet@hotmail.com; Boukhachem, A.; Amlouk, M.; Manoubi, T.

    2016-05-05

    This work highlights some physical investigations on tin oxide thin films doped with different lanthanum content (ratio La–to-Sn = 0–3%). Such doped thin films have been successfully grown by spray pyrolysis onto glass substrates at 450 °C. X-ray diffraction (XRD) patterns showed that SnO{sub 2}:La thin films were polycrystalline with tetragonal crystal structure. The preferred orientation of crystallites for undoped SnO{sub 2} thin film was along (110) plane, whereas La-doped ones have rather preferential orientations along (200) direction. Although the grain size values exhibited a decreasing tendency with increasing doping content confirming the role of La as a grain growth inhibitor, dislocation density and microstrain values showed an increasing tendency. Also, Raman spectroscopy shows the bands corresponding to the tetragonal structure for the entire range of La doping. The same technique confirms the presence of La{sub 2}O{sub 3} as secondary phase. Moreover, SEM images showed a porous architecture with presence of big clusters with different sizes and shapes resulting from the agglomeration of small grains round shaped. Photoluminescence spectra of SnO{sub 2}:La thin films exhibit a decrease in the emission intensity with La concentration due to the decrease in grain size. Optical transmittance spectra of the films showed high transparency (∼80%) in the visible region. The dispersion of the refractive index is discussed using both Cauchy model and Wemple–Di-Domenico method. The optical band gap values vary slightly with La doping and were found to be around 3.8 eV. It has been found that La doping causes a pronounced decrease in the sheet resistance by up to two orders of magnitude and allows improving the Haacke's figure of merit (Φ) of the sprayed thin films. Moreover, we have introduced for a first time a new figure of merit for qualifying photo-thermal conversion applications. The obtained high conducting and transparent SnO{sub 2}:La

  17. Effect of the type of metal on the electrical conductivity and thermal properties of metal complexes: The relation between ionic radius of metal complexes and electrical conductivity

    Science.gov (United States)

    Morgan, Sh. M.; El-Ghamaz, N. A.; Diab, M. A.

    2018-05-01

    Co(II) complexes (1-4) and Ni(II) complexes (5-8) were prepared and characterized by elemental analysis, IR spectra and thermal analysis data. Thermal decomposition of all complexes was discussed using thermogravimetric analysis. The dielectric properties and alternating current conductivity were investigated in the frequency range 0.1-100 kHz and temperature range 300-660 K. The thermal activation energies of electrical conductivity (ΔE1 and ΔE2) values for complexes were calculated and discussed. The values of ΔE1 and ΔE2 for complexes (1-8) were found to decrease with increasing the frequency. Ac electrical conductivity (σac) values increases with increasing temperatures and the values of σac for Co(II) complexes are greater than Ni(II) complexes. Co(II) complexes showed a higher conductivity than other Ni(II) complexes due to the higher crystallinity as confirmed by X-ray diffraction analysis.

  18. Electrical and mechanical properties of asphalt concrete containing conductive fibers and fillers

    NARCIS (Netherlands)

    Wang, H.; Yang, Jun; Liao, Hui; Chen, Xianhua

    2016-01-01

    Electrically conductive asphalt concrete has the potential to satisfy multifunctional applications. Designing such asphalt concrete needs to balance the electrical and mechanical performance of asphalt concrete. The objective of this study is to design electrically conductive asphalt concrete

  19. The thermal properties of a carbon nanotube-enriched epoxy: Thermal conductivity, curing, and degradation kinetics

    KAUST Repository

    Ventura, Isaac Aguilar; Rahaman, Ariful; Lubineau, Gilles

    2013-01-01

    conductivity, and degradation kinetics were studied. Introducing the MWCNTs increased the curing activation energy as revealed by differential scanning calorimetry. The final thermal conductivity of the 0.5 and 1.0 wt % MWCNT-enriched epoxy samples measured

  20. UV-screening, transparency and water barrier properties of semi refined iota carrageenan packaging film incorporated with ZnO nanoparticles

    Science.gov (United States)

    Khoirunnisa, Assifa Rahma; Joni, I. Made; Panatarani, Camellia; Rochima, Emma; Praseptiangga, Danar

    2018-02-01

    This study aims to develop film for food packaging application with high UV-screening, transparency and water barrier properties. Semi refined iota carrageenan (SRiC) nanocomposite films prepared by addition of zinc oxide (ZnO) nanoparticles as nanofiller using solution casting method. The effect of nanofiller with different concentration (0%, 0.5%, 1.0%, 1.5% w/w carrageenan) on UV-screening, transparency and water barrier properties of films were tested. The water barrier properties of the films were studied by measuring water vapor permeability (WVP) and the optical properties of the films were studied by using UV-Vis spectrophotometer at 280 nm for UV-screening test and at 660 nm for transparency test. WVP value of carrageenan films with addition of ZnO is low compared to a control carrageenan film and the lowest WVP value was found for the film with addition of 1.5% of ZnO. These result indicate that the addition of ZnO had a positive effect on the water barrier properties of the carrageenan matrix. Increase in the concentration of nanofiller leads to an increase in the UV-screening properties. Among all the films, carrageenan film with 1.5% ZnO has the highest UV-screening. The result showed that adding 0.5% and 1.0% of ZnO was insignificantly affect transparency of the films, however the transparency decreased sligthly when 1.5% ZnO was added. In conclusion, incorporating no more than 1.0% of ZnO to the films can obtain films with high UV-screening, transparency and water barrier properties and suitable for food packaging application.

  1. Estimation of cloud optical thickness by processing SEVIRI images and implementing a semi analytical cloud property retrieval algorithm

    Science.gov (United States)

    Pandey, P.; De Ridder, K.; van Lipzig, N.

    2009-04-01

    Clouds play a very important role in the Earth's climate system, as they form an intermediate layer between Sun and the Earth. Satellite remote sensing systems are the only means to provide information about clouds on large scales. The geostationary satellite, Meteosat Second Generation (MSG) has onboard an imaging radiometer, the Spinning Enhanced Visible and Infrared Imager (SEVIRI). SEVIRI is a 12 channel imager, with 11 channels observing the earth's full disk with a temporal resolution of 15 min and spatial resolution of 3 km at nadir, and a high resolution visible (HRV) channel. The visible channels (0.6 µm and 0.81 µm) and near infrared channel (1.6µm) of SEVIRI are being used to retrieve the cloud optical thickness (COT). The study domain is over Europe covering the region between 35°N - 70°N and 10°W - 30°E. SEVIRI level 1.5 images over this domain are being acquired from the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) archive. The processing of this imagery, involves a number of steps before estimating the COT. The steps involved in pre-processing are as follows. First, the digital count number is acquired from the imagery. Image geo-coding is performed in order to relate the pixel positions to the corresponding longitude and latitude. Solar zenith angle is determined as a function of latitude and time. The radiometric conversion is done using the values of offsets and slopes of each band. The values of radiance obtained are then used to calculate the reflectance for channels in the visible spectrum using the information of solar zenith angle. An attempt is made to estimate the COT from the observed radiances. A semi analytical algorithm [Kokhanovsky et al., 2003] is implemented for the estimation of cloud optical thickness from the visible spectrum of light intensity reflected from clouds. The asymptotical solution of the radiative transfer equation, for clouds with large optical thickness, is the basis of

  2. Mechanical and Barrier Properties of Semi Refined Kappa Carrageenan-based Composite Edible Film and Its Application on Minimally Processed Chicken Breast Fillet

    Science.gov (United States)

    Praseptiangga, D.; Maimuni, B. H.; Manuhara, G. J.; Muhammad, D. R. A.

    2018-03-01

    Kappa-carrageenan (KC) is one of the most interesting biopolymers that is composed of a linear chain of sulfated galactans and extracted from red seaweed, Kappaphycus alvarezii. It shows good potential for development as a source of biodegradable or edible films. However, KC films do not have good water vapor barrier properties, as they are intrinsically hydrophilic. Palmitic acid (PA) as hydrophobic material was incorporated into semi-refined kappa-carrageenan (SRKC) edible films in order to improve water vapor barrier properties. In this study, composite films based on SRKC incorporating PA were prepared and their applications on minimally processed chicken breast fillet were evaluated. Composite SRKC-based films with varying concentrations of PA (5%, 10%, and 15% w/w) were obtained by a solvent casting method. Their mechanical and barrier properties were investigated. Results showed that the incorporation of PA in films caused an increase in thickness, but decrease in water vapor transmission rate (WVTR) as the concentration of PA increased (from 5% to 15% w/w). Composite SRKC-based edible film incorporating 15% w/w of PA presented better water vapor barrier properties as compared to other films with 5% and 10% w/w PA incorporation. Thus, formulation containing 15% w/w PA was used as a wrapping material for film application on minimally processed chicken breast fillet. The application results showed that the incorporation of PA in film caused an effect (p 0.05) change the color of minimally processed chicken breast fillet.

  3. Ecosystem properties of semi-arid savanna grassland in West Africa and its relationship to environmental variability

    DEFF Research Database (Denmark)

    Tagesson, Torbern; Fensholt, Rasmus; Guiro, Idrissa

    2015-01-01

    he Dahra field site in Senegal, West Africa, was established in 2002 to monitor ecosystem properties of semiarid savanna grassland and their responses to climatic and environmental change. This article describes the environment and the ecosystem properties of the site using a unique set of in situ......), biomass, vegetation water content, and land-atmosphere exchanges of carbon (NEE) and energy. The Dahra field site experiences a typical Sahelian climate and is covered by coexisting trees (~3% canopy cover) and grass species, characterizing large parts of the Sahel. This makes the site suitable...

  4. Changes in Properties of Auditory Nerve Synapses following Conductive Hearing Loss.

    Science.gov (United States)

    Zhuang, Xiaowen; Sun, Wei; Xu-Friedman, Matthew A

    2017-01-11

    Auditory activity plays an important role in the development of the auditory system. Decreased activity can result from conductive hearing loss (CHL) associated with otitis media, which may lead to long-term perceptual deficits. The effects of CHL have been mainly studied at later stages of the auditory pathway, but early stages remain less examined. However, changes in early stages could be important because they would affect how information about sounds is conveyed to higher-order areas for further processing and localization. We examined the effects of CHL at auditory nerve synapses onto bushy cells in the mouse anteroventral cochlear nucleus following occlusion of the ear canal. These synapses, called endbulbs of Held, normally show strong depression in voltage-clamp recordings in brain slices. After 1 week of CHL, endbulbs showed even greater depression, reflecting higher release probability. We observed no differences in quantal size between control and occluded mice. We confirmed these observations using mean-variance analysis and the integration method, which also revealed that the number of release sites decreased after occlusion. Consistent with this, synaptic puncta immunopositive for VGLUT1 decreased in area after occlusion. The level of depression and number of release sites both showed recovery after returning to normal conditions. Finally, bushy cells fired fewer action potentials in response to evoked synaptic activity after occlusion, likely because of increased depression and decreased input resistance. These effects appear to reflect a homeostatic, adaptive response of auditory nerve synapses to reduced activity. These effects may have important implications for perceptual changes following CHL. Normal hearing is important to everyday life, but abnormal auditory experience during development can lead to processing disorders. For example, otitis media reduces sound to the ear, which can cause long-lasting deficits in language skills and verbal

  5. Electrochemical properties of mixed conducting (La,M)(CoFe) oxide perovskites (M=3DSr, Ca, and Ba)

    Energy Technology Data Exchange (ETDEWEB)

    Stevenson, J.W.; Armstrong, T.R.; Bates, J.L. [and others

    1996-04-01

    Electrical properties and oxygen permeation properties of solid mixed-conducting electrolytes (La,M)(CoFe) oxide perovskites (M=3DSr, Ca, and Ba) have been characterized. These materials are potentially useful as passive membranes to separate high purity oxygen from air and as the cathode in a fuel cell. Dilatometric linear expansion measurements were performed as a function of temperature and oxygen partial pressure to evaluate the stability.

  6. A study of tensile and thermal properties of 3D printed conductive ABS - ZnO composite

    Science.gov (United States)

    Aw, Y. Y.; Yeoh, C. K.; Idris, M. A.; Amali, H. K.; Aqzna, S. S.; Teh, P. L.

    2017-04-01

    Research into 3D printed composites are interesting because the properties of 3D printed components are usually insufficient for robust engineering applications. In this paper, conductive ABS - ZnO composites were successfully fabricated using a 3D printer. Tensile strength increases when filler loading increases up to 11wt%. Dynamic storage modulus of the conductive ABS-ZnO composite increases with the addition of ZnO filler, indicating stiffness enhancement of the composites. Higher loss modulus is also observed on samples with ZnO filler. Thermal conductivity increases from 0.2204 W/mK to 0.3508 W/mK when the filler concentration increases to 14wt% due to the formation of conductive network among fillers within the polymer matrix. With these promising tensile and thermal properties, the 3D printed composites are suitable to be used as automobile parts.

  7. Dynamics of nonequilibrium conductivity of dielectrics with polaration properties controlled by in ection

    International Nuclear Information System (INIS)

    Arkhipov, V.I.; Rudenko, A.I.

    1979-01-01

    The effect of changes of radiation stimulation permittivity on nonequilibrium conductivity of dielectrics and high-resistance conductors in a radiation field has been studied theoretically. The plane-parallel sample under the constant voltage has been irradiated by penetrating radiation. The uniform radiation caused the transfer the current carriers from traps to the conduction band. The dependence of permittivity on charged traps concentration is shown to lead to negative nonequilibrium conductivity of high-resistance materials

  8. The study of heat conductivity properties of GdS1.48 and DyS1.48

    International Nuclear Information System (INIS)

    Ahmadov, O.R.

    2009-01-01

    The heat conductivity properties of sulfides of gadolinium and dysprosium up to 900 K with use of the average speed of ultrasound distribution, a specific thermal capacity and Viderman-Frans law have been investigated. The value of Debay temperature, thermal extension coefficient and the temperature dependence are established. It is shown that the scattering on crystal lattice phonons plays the main role in lattice heat conductivity

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1976-10-08

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

  10. Effect of pH on the electrical properties and conducting mechanism of SnO{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Periathai, R.Sudha [Department of Physics, Standard Fireworks Rajaratnam College for Women, Sivakasi 626123 (India); Abarna, S.; Hirankumar, G. [Centre for Scientific and Applied Research, PSN College of Engineering and Technology, Tirunelveli 627152 (India); Jeyakumaran, N. [Department of Physics, V.H.N. Senthikumara Nadar College, Virudhunagar 626001 (India); Prithivikumaran, N., E-mail: janavi_p@yahoo.com [Department of Physics, V.H.N. Senthikumara Nadar College, Virudhunagar 626001 (India)

    2017-03-15

    Semiconductor nanoparticles have attracted more interests because of their size-dependent optical and electrical properties.SnO{sub 2} is an oxygen-deficient n-type semiconductor with a wide band gap of 3.6 eV (300 K). It has many remarkable applications as sensors, catalysts, transparent conducting electrodes, anode material for rechargeable Li- ion batteries and optoelectronic devices. In the present work, the role of pH in determining the electrical and dielectric properties of SnO{sub 2} nanoparticles has been studied as a function of temperature ranging from Room temperature (RT) to 114 °C in the frequency range of 7 MHz to 50 mHz using impedance spectroscopic technique. The non linear behavior observed in the thermal dependence of the conductance of SnO{sub 2} nanoparticles is explained by means of the surface property of SnO{sub 2} nanoparticles where proton hopping mechanism is dealt with. Jonscher's power law has been fitted for the conductance spectra and the frequency exponent (“s” value) gives an insight about the ac conducting mechanism. The temperature dependence of electrical relaxation phenomenon in the material has been observed. The complex electric modulus analysis indicates the possibility of hopping conduction mechanism in the system with non-exponential type of conductivity relaxation.

  11. Effect of pH on the electrical properties and conducting mechanism of SnO_2 nanoparticles

    International Nuclear Information System (INIS)

    Periathai, R.Sudha; Abarna, S.; Hirankumar, G.; Jeyakumaran, N.; Prithivikumaran, N.

    2017-01-01

    Semiconductor nanoparticles have attracted more interests because of their size-dependent optical and electrical properties.SnO_2 is an oxygen-deficient n-type semiconductor with a wide band gap of 3.6 eV (300 K). It has many remarkable applications as sensors, catalysts, transparent conducting electrodes, anode material for rechargeable Li- ion batteries and optoelectronic devices. In the present work, the role of pH in determining the electrical and dielectric properties of SnO_2 nanoparticles has been studied as a function of temperature ranging from Room temperature (RT) to 114 °C in the frequency range of 7 MHz to 50 mHz using impedance spectroscopic technique. The non linear behavior observed in the thermal dependence of the conductance of SnO_2 nanoparticles is explained by means of the surface property of SnO_2 nanoparticles where proton hopping mechanism is dealt with. Jonscher's power law has been fitted for the conductance spectra and the frequency exponent (“s” value) gives an insight about the ac conducting mechanism. The temperature dependence of electrical relaxation phenomenon in the material has been observed. The complex electric modulus analysis indicates the possibility of hopping conduction mechanism in the system with non-exponential type of conductivity relaxation.

  12. Low-temperature properties of orientationally degenerated (OH)- centers in proton-conducting oxides

    International Nuclear Information System (INIS)

    Ivanov, M.A.; Fishman, A.Ya.; Tsidil'kovsky, V.I.

    2007-01-01

    It is shown that the proton-associated dipole centers (OH) - can provide glasslike low-temperature properties of ABO 3-y oxides doped with cations of lower valence. These properties result from the splitting of the orientationally degenerated states of the (OH) - centers by proton tunnelling and random crystal fields. It is found that the substitution of hydrogen by deuterium or tritium leads to large and abnormal isotope effects for the contributions of degenerated centers to thermodynamic properties and absorption of elastic and electromagnetic waves

  13. Effect of H{sup +} implantation on the optical properties of semi-insulating GaAs crystals in the IR spectral region

    Energy Technology Data Exchange (ETDEWEB)

    Klyui, N. I.; Lozinskii, V. B., E-mail: lvb@isp.kiev.ua [Jilin University, College of Physics (China); Liptuga, A. I.; Dikusha, V. N. [National Academy of Sciences of Ukraine, Lashkaryov Institute of Semiconductor Physics (Ukraine); Oksanych, A. P.; Kogdas’, M. G.; Perekhrest, A. L.; Pritchin, S. E. [Kremenchug National University (Ukraine)

    2017-03-15

    The optical properties of semi-insulating GaAs crystals subjected to multienergy hydrogen-ion implantation and treatment in a high-frequency electromagnetic field are studied in the infrared spectral region. It is established that such combined treatment provides a means for substantially increasing the transmittance of GaAs crystals to values characteristic of crystals of high optical quality. On the basis of analysis of the infrared transmittance and reflectance data, Raman spectroscopy data, and atomic-force microscopy data on the surface morphology of the crystals, a physical model is proposed to interpret the effects experimentally observed in the crystals. The model takes into account the interaction of radiation defects with the initial structural defects in the crystals as well as the effect of compensation of defect centers by hydrogen during high-frequency treatment.

  14. Effect of H+ implantation on the optical properties of semi-insulating GaAs crystals in the IR spectral region

    International Nuclear Information System (INIS)

    Klyui, N. I.; Lozinskii, V. B.; Liptuga, A. I.; Dikusha, V. N.; Oksanych, A. P.; Kogdas’, M. G.; Perekhrest, A. L.; Pritchin, S. E.

    2017-01-01

    The optical properties of semi-insulating GaAs crystals subjected to multienergy hydrogen-ion implantation and treatment in a high-frequency electromagnetic field are studied in the infrared spectral region. It is established that such combined treatment provides a means for substantially increasing the transmittance of GaAs crystals to values characteristic of crystals of high optical quality. On the basis of analysis of the infrared transmittance and reflectance data, Raman spectroscopy data, and atomic-force microscopy data on the surface morphology of the crystals, a physical model is proposed to interpret the effects experimentally observed in the crystals. The model takes into account the interaction of radiation defects with the initial structural defects in the crystals as well as the effect of compensation of defect centers by hydrogen during high-frequency treatment.

  15. Effect of the thickness and hydrogen treatment on the properties of Ga-doped ZnO transparent conductive films

    International Nuclear Information System (INIS)

    Lee, Min-Jung; Lim, Jinhyong; Bang, Jungsik; Lee, Woong; Myoung, Jae-Min

    2008-01-01

    Combined effects of the thickness and hydrogen post-annealing treatment on the structural, electrical, and optical properties of Ga-doped ZnO (GZO) films were investigated as a potential substitute for indium tin oxide transparent conductive oxide. In the as-deposited films, microstructural evolution initially improved the crystallinity up to the thickness of 160 nm accompanying enhanced electrical and optical properties, but further thickness increase resulted in the deterioration of these properties attributable to the development of ZnGa 2 O 4 and Ga 2 O 3 phases originating from the excessive amount of the Ga dopant. Post-annealing treatment of the GZO films in a hydrogen atmosphere improved the electrical and optical properties substantially through possible reduction of the oxide phases and passivation of the surfaces and grain boundaries. In this case, electrical and optical properties remained almost similar for the thickness above 160 nm indicating that there exists a certain optimal film thickness.

  16. Pyroelectric properties and electrical conductivity in samarium doped BiFeO 3 ceramics

    KAUST Repository

    Yao, Yingbang; Liu, Wenchao; Mak, C. L.

    2012-01-01

    . This electrical conduction was attributed to oxygen vacancy existing in the samples. An activation energy of ∼0.7 eV for the conduction process was found to be irrespective of the Sm 3+ doping level. On the other hand, the magnetic Néel temperature (T N) decreased

  17. Cross-linked sulfonated aromatic ionomers via SO2 bridges: Conductivity properties

    Science.gov (United States)

    Di Vona, M. L.; Pasquini, L.; Narducci, R.; Pelzer, K.; Donnadio, A.; Casciola, M.; Knauth, P.

    2013-12-01

    The proton conductivity of SPEEK membranes in situ cross-linked by thermal treatment at 180 °C for various times was investigated by impedance spectroscopy. The conductivity measurements were made on fully humidified membranes between 25 and 65 °C and on membranes exposed to different relative humidity between 80 and 140 °C. The Ionic Exchange Capacity (IEC) was determined by acid-base titration and the water uptake by gravimetry. The proton conductivity was determined as function of temperature, IEC, degree of cross-linking and hydration number. A curve of proton conductivity vs. hydration number allows predicting that in order to reach a value of 0.1 S/cm at 100 °C a hydration number above 20 is necessary. The measured conductivity at this temperature is 0.16 S/cm for a hydration number of 60.

  18. The effects of deep level traps on the electrical properties of semi-insulating CdZnTe

    Energy Technology Data Exchange (ETDEWEB)

    Zha, Gangqiang; Yang, Jian; Xu, Lingyan; Feng, Tao; Wang, Ning; Jie, Wanqi [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an (China)

    2014-01-28

    Deep level traps have considerable effects on the electrical properties and radiation detection performance of high resistivity CdZnTe. A deep-trap model for high resistivity CdZnTe was proposed in this paper. The high resistivity mechanism and the electrical properties were analyzed based on this model. High resistivity CdZnTe with high trap ionization energy E{sub t} can withstand high bias voltages. The leakage current is dependent on both the deep traps and the shallow impurities. The performance of a CdZnTe radiation detector will deteriorate at low temperatures, and the way in which sub-bandgap light excitation could improve the low temperature performance can be explained using the deep trap model.

  19. Investigations on electrical conductivity and dielectric properties of Na doped ZnO synthesized from sol gel method

    Energy Technology Data Exchange (ETDEWEB)

    Tabib, Asma; Sdiri, Nasr [Laboratoire de Physico-Chimie des Matériaux Minéraux et leurs Applications, Centre National de Recherches en Sciences des Matériaux, B.P. 95 Hammam-Lif, 2050 (Tunisia); Elhouichet, Habib, E-mail: habib.elhouichet@fst.rnu.tn [Laboratoire de Physico-Chimie des Matériaux Minéraux et leurs Applications, Centre National de Recherches en Sciences des Matériaux, B.P. 95 Hammam-Lif, 2050 (Tunisia); Département de Physique, Faculté des Sciences de Tunis, University Tunis El Manar, Tunis 2092 (Tunisia); Férid, Mokhtar [Laboratoire de Physico-Chimie des Matériaux Minéraux et leurs Applications, Centre National de Recherches en Sciences des Matériaux, B.P. 95 Hammam-Lif, 2050 (Tunisia)

    2015-02-15

    Highlights: • ZnO nanoparticles doped with Na were prepared from sol-gel method. • Electric conductivity and dielectric properties were investigated. • The ZnO conductivity is estimated to be of p-type for critical Na doping of 1.5% at. - Abstract: Na doped ZnO nanoparticles (NPs) were elaborated by sol gel technique. The X-ray diffraction patterns show that the peaks are indexed to the hexagonal structure without any trace of an extra phase. Electric and dielectric properties were investigated using complex impedance spectroscopy. The impedance spectra were analyzed in terms of equivalent circuits involving resistors, capacitors and constant phase elements (CPE). The contribution of grain boundary resistance to the total resistance of the system is remarkable. The AC conductivity increases with temperature following the Arrhenius law, with single apparent activation energy for conduction process. The frequency dependence of the electric conductivity follows a simple power law behavior, in according to relation σ{sub AC}(ω) = σ(0) + A ω{sup s}, where s is smaller than 1. The analysis of dc conductivity indicates that the conduction is ionic in nature. The study of its variation, at fixed temperature, with Na content shows sharp decrease which is explained by the formation of Na{sub Zn} acceptor. It was found that the dc conductivity reaches its minimum value for critical Na concentration of 1.5% at which the conductivity is estimated to be of p-type. Impedance and modulus study reveals the temperature dependent non-Debye type relaxation phenomenon. Dielectric studies revealed a promising dielectric properties (relatively high ε′ at low frequencies and low loss at high frequencies). In the low-frequency region, the values of M′ tends to zero suggesting negligible or absent electrode polarization phenomenon. The frequency dependent maxima in the imaginary modulus are found to obey to Arrhenius law.

  20. Optical transparency and mechanical properties of semi-refined iota carrageenan film reinforced with SiO2 as food packaging material

    Science.gov (United States)

    Aji, Afifah Iswara; Praseptiangga, Danar; Rochima, Emma; Joni, I. Made; Panatarani, Camellia

    2018-02-01

    Food packaging is important for protecting food from environmental influences such as heat, light, water vapor, oxygen, dirt, dust particles, gas emissions and so on, which leads to decrease the quality of food. The most widely used type of packaging in the food industry is plastic which is made from synthetic polymers and takes hundreds of years to biodegrade. Recently, food packaging with high bio-degradability is being developed using biopolymer combined with nanoparticles as reinforcing agent (filler) to improve its properties. In this study, semi-refined iota carrageenan films were prepared by incorporating SiO2 nanoparticles as filler at different concentrations (0%, 0.5%, 1.0% and 1.5% w/w carrageenan) using solution casting method. The optical transparency and mechanical properties (tensile strength and elongation at break) of the films were analyzed. The results showed that incorporation of SiO2 nanoparticles to carrageenan matrix on optical transparency of the films. For the mechanical properties, the highest tensile strength was found for incorporation of 0.5% SiO2, while the elongation at break of the films improved with increasing SiO2 concentration.

  1. Improved electrical conduction properties in unintentionally-doped ZnO thin films treated by rapid thermal annealing

    International Nuclear Information System (INIS)

    Lee, Youngmin; Lee, Choeun; Shim, Eunhee; Jung, Eiwhan; Lee, Jinyong; Kim, Deukyoung; Lee, Sejoon; Fu, Dejun; Yoon, Hyungdo

    2011-01-01

    The effects of thermal treatments on the electrical conduction properties for the unintentionally doped ZnO thin films were investigated. Despite the decreased carrier density in the annealed ZnO thin films, the conductivity was increased because the contribution of the effective carrier mobility to the conductivity of the unintentionally-doped ZnO thin films is greater than that of the carrier density. The resistivity exponentially decreased with increasing RTA temperature, and this result was confirmed to come from the enhanced effective carrier-mobility, which originated from the increased crystallite size in the annealed ZnO thin films.

  2. Improved electrical conduction properties in unintentionally-doped ZnO thin films treated by rapid thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Youngmin; Lee, Choeun; Shim, Eunhee; Jung, Eiwhan; Lee, Jinyong; Kim, Deukyoung; Lee, Sejoon [Dongguk University-Seoul, Seoul (Korea, Republic of); Fu, Dejun [Wuhan University, Wuhan (China); Yoon, Hyungdo [Korea Electronics Technology Institute, Seongnam (Korea, Republic of)

    2011-10-15

    The effects of thermal treatments on the electrical conduction properties for the unintentionally doped ZnO thin films were investigated. Despite the decreased carrier density in the annealed ZnO thin films, the conductivity was increased because the contribution of the effective carrier mobility to the conductivity of the unintentionally-doped ZnO thin films is greater than that of the carrier density. The resistivity exponentially decreased with increasing RTA temperature, and this result was confirmed to come from the enhanced effective carrier-mobility, which originated from the increased crystallite size in the annealed ZnO thin films.

  3. Thermoelectric Properties of Solution-Processed n-Doped Ladder-Type Conducting Polymers

    DEFF Research Database (Denmark)

    Wang, Suhao; Sun, Hengda; Ail, Ujwala

    2016-01-01

    Ladder-type "torsion-free" conducting polymers (e.g., polybenzimidazobenzophenanthroline (BBL)) can outperform "structurally distorted" donor-acceptor polymers (e.g., P(NDI2OD-T2)), in terms of conductivity and thermoelectric power factor. The polaron delocalization length is larger in BBL than...... in P(NDI2OD-T2), resulting in a higher measured polaron mobility. Structure-function relationships are drawn, setting material-design guidelines for the next generation of conducting thermoelectric polymers....

  4. Electrical property heterogeneity at transparent conductive oxide/organic semiconductor interfaces: mapping contact ohmicity using conducting-tip atomic force microscopy.

    Science.gov (United States)

    MacDonald, Gordon A; Veneman, P Alexander; Placencia, Diogenes; Armstrong, Neal R

    2012-11-27

    We demonstrate mapping of electrical properties of heterojunctions of a molecular semiconductor (copper phthalocyanine, CuPc) and a transparent conducting oxide (indium-tin oxide, ITO), on 20-500 nm length scales, using a conductive-probe atomic force microscopy technique, scanning current spectroscopy (SCS). SCS maps are generated for CuPc/ITO heterojunctions as a function of ITO activation procedures and modification with variable chain length alkyl-phosphonic acids (PAs). We correlate differences in small length scale electrical properties with the performance of organic photovoltaic cells (OPVs) based on CuPc/C(60) heterojunctions, built on these same ITO substrates. SCS maps the "ohmicity" of ITO/CuPc heterojunctions, creating arrays of spatially resolved current-voltage (J-V) curves. Each J-V curve is fit with modified Mott-Gurney expressions, mapping a fitted exponent (γ), where deviations from γ = 2.0 suggest nonohmic behavior. ITO/CuPc/C(60)/BCP/Al OPVs built on nonactivated ITO show mainly nonohmic SCS maps and dark J-V curves with increased series resistance (R(S)), lowered fill-factors (FF), and diminished device performance, especially near the open-circuit voltage. Nearly optimal behavior is seen for OPVs built on oxygen-plasma-treated ITO contacts, which showed SCS maps comparable to heterojunctions of CuPc on clean Au. For ITO electrodes modified with PAs there is a strong correlation between PA chain length and the degree of ohmicity and uniformity of electrical response in ITO/CuPc heterojunctions. ITO electrodes modified with 6-8 carbon alkyl-PAs show uniform and nearly ohmic SCS maps, coupled with acceptable CuPc/C(60)OPV performance. ITO modified with C14 and C18 alkyl-PAs shows dramatic decreases in FF, increases in R(S), and greatly enhanced recombination losses.

  5. Analysis of the conduction mechanism and dielectric properties of N, N', N" tris(4-methylphenyl)phosphoric triamide

    Science.gov (United States)

    Ali, H. A. M.

    2016-03-01

    The structure for the powder of N,N', N"-tris(4-methylphenyl)phosphoric triamide, TMP-TA, was characterized using X-ray diffraction (XRD) and differential thermal analysis (DTA) techniques. The ac conductivity and dielectric properties were measured in the frequency range of 42-105 Hz for the bulk TMP-TA in a pellet form at different temperatures. The frequency dependence of ac conductivity was expressed by a Jonscher's universal power law. The frequency exponent (s) was determined from the fitting of experimental data of ac conductivity. The correlated barrier hopping (CBH) model was found to be responsible for the ac conduction mechanism in TMP-TA. The activation energy was calculated from the temperature dependence of ac conductivity. The values of the density of states at the Fermi level were determined for different frequencies. The components of the electric modulus (M' and M") were calculated and used to estimate the relaxation time.

  6. Electrical conduction and thermal properties of Bi-doped Pr0·7Sr0 ...

    Indian Academy of Sciences (India)

    mal conductivity and thermo-power measurements show that larger Bi-ion, in place of smaller Pr ion, enhances ... correlated electron system and technological applications because of ..... doping level (c) indicate the reliability of fitting with this.

  7. Studies on physical properties of cadmium soaps. Part 2. Conductance behavior in 1-butanol

    International Nuclear Information System (INIS)

    Varma, R.P.; Virmani, A.K.

    1981-01-01

    Specific conductance of cadmium soap solutions in 1-butanol has been measured at temperatures 308-323 K. These soaps form micellar aggregates and the c.m.c. which increases with decreasing chain length of the soaps (C 18 -C 5 ) has been found to be independent of temperature. Conductance behavior of soaps is given by the equation: log lambda = A+B log C. log lambda = A+B log C. Constant A decreases with increasing temperature, whereas B is found independent. These constants, however, increase with an increase in the chain length of the soaps. Dissociation constant K, molecular conductance at infinite dilution lamda infinity, activation energy of conductance ΔE lamda, and activation parameters of dissociation ΔH 0 , ΔG 0 and ΔS 0 have been evaluated. (author)

  8. Impression creep properties of a semi-solid processed magnesium-aluminum alloy containing calcium and rare earth elements

    International Nuclear Information System (INIS)

    Nami, B.; Razavi, H.; Miresmaeili, S.M.; Mirdamadi, Sh.; Shabestari, S.G.

    2011-01-01

    The creep properties of a thixoformed magnesium-aluminum alloy containing calcium and rare earth elements were studied under shear modulus-normalized stresses ranging from 0.0225 to 0.035 at temperatures of 150-212 o C using the impression creep technique. Analysis of the creep mechanism based on a power-law equation indicated that pipe diffusion-controlled dislocation climb is the dominant mechanism during creep. The alloy has a better creep resistance than high-pressure die-cast magnesium-aluminum alloy.

  9. Enhanced AC conductivity and dielectric relaxation properties of polypyrrole nanoparticles irradiated with Ni12+ swift heavy ions

    International Nuclear Information System (INIS)

    Hazarika, J.; Kumar, A.

    2014-01-01

    In this paper, we report the 160 MeV Ni 12+ swift heavy ions (SHIs) irradiation effects on AC conductivity and dielectric relaxation properties of polypyrrole (PPy) nanoparticles in the frequency range of 42 Hz–5 MHz. Four ion fluences of 5 × 10 10 , 1 × 10 11 , 5 × 10 11 and 1 × 10 12 ions/cm 2 have been used for the irradiation purpose. Transport properties in the pristine and irradiated PPy nanoparticles have been investigated with permittivity and modulus formalisms to study the polarization effects and conductivity relaxation. With increasing ion fluence, the relaxation peak in imaginary modulus (M ″ ) plots shifts toward high frequency suggesting long range motion of the charge carriers. The AC conductivity studies suggest correlated barrier hopping as the dominant transport mechanism. The hopping distance (R ω ) of the charge carriers decreases with increasing the ion fluence. Binding energy (W m ) calculations depict that polarons are the dominant charge carriers

  10. Optimization of electrical conduction and passivity properties of stainless steels used for PEM fuel cell bipolar plates; Opmisation des proprietes de conduction electrique et de passivite d'aciers inoxydables pour la realisation de plaques bipolaires de pile a combustible de type PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Andre, J

    2007-10-15

    Among the new technologies for energy for sustainable development, PEMFC (proton exchange membrane fuel cells) offer seducing aspects. However, in order to make this technology fit large scale application requirements, it has to comply with stringent cost, performance, and durability criteria. In such a frame, the goal of this work was to optimize electrical conduction properties and passivity of stainless steels for the conception of PEMFC bipolar plates, used instead of graphite, the reference material. This work presents the possible ways of performance loss when using stainless steels and some methods to solve this problem. Passive film properties were studied, as well as their modifications by low cost industrial surface treatments, without deposition. Ex situ characterizations of corrosion resistance and electrical conduction were performed. Electrochemical impedance spectroscopy, water analysis, surface analysis by microscopy and photoelectron spectroscopy allowed to study the impact of ageing on two alloys in different states, and several conditions representative of an exposure to PEMFC media. Correlations between semi-conductivity properties, composition, and structure of passive layers were considered, but not leading to clear identification of all parameters responsible for electrical conduction and passivity. The plate industrial state is not convenient for direct use in fuel cell to comply with durability and performance requirements. A surface modification studied improves widely electrical conduction at initial state. The performance is degraded with ageing, but maintaining a level higher than the initial industrial state. This treatment increases also corrosion resistance, particularly on the anode side. (author)

  11. Optimization of electrical conduction and passivity properties of stainless steels used for PEM fuel cell bipolar plates; Opmisation des proprietes de conduction electrique et de passivite d'aciers inoxydables pour la realisation de plaques bipolaires de pile a combustible de type PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Andre, J

    2007-10-15

    Among the new technologies for energy for sustainable development, PEMFC (proton exchange membrane fuel cells) offer seducing aspects. However, in order to make this technology fit large scale application requirements, it has to comply with stringent cost, performance, and durability criteria. In such a frame, the goal of this work was to optimize electrical conduction properties and passivity of stainless steels for the conception of PEMFC bipolar plates, used instead of graphite, the reference material. This work presents the possible ways of performance loss when using stainless steels and some methods to solve this problem. Passive film properties were studied, as well as their modifications by low cost industrial surface treatments, without deposition. Ex situ characterizations of corrosion resistance and electrical conduction were performed. Electrochemical impedance spectroscopy, water analysis, surface analysis by microscopy and photoelectron spectroscopy allowed to study the impact of ageing on two alloys in different states, and several conditions representative of an exposure to PEMFC media. Correlations between semi-conductivity properties, composition, and structure of passive layers were considered, but not leading to clear identification of all parameters responsible for electrical conduction and passivity. The plate industrial state is not convenient for direct use in fuel cell to comply with durability and performance requirements. A surface modification studied improves widely electrical conduction at initial state. The performance is degraded with ageing, but maintaining a level higher than the initial industrial state. This treatment increases also corrosion resistance, particularly on the anode side. (author)

  12. The influence of Ga{sup +} irradiation on the transport properties of mesoscopic conducting thin films

    Energy Technology Data Exchange (ETDEWEB)

    Barzola-Quiquia, J; Dusari, S; Bridoux, G; Bern, F; Molle, A; Esquinazi, P, E-mail: j.barzola@physik.uni-leipzig.de, E-mail: esquin@physik.uni-leipzig.de [Division of Superconductivity and Magnetism, Universitaet Leipzig, Linnestrasse 5, D-04103 Leipzig (Germany)

    2010-04-09

    We studied the influence of 30 keV Ga{sup +}-ions-commonly used in focused-ion-beam (FIB) devices-on the transport properties of thin crystalline graphite flakes, and La{sub 0.7}Ca{sub 0.3}MnO{sub 3} and Co thin films. The changes in electrical resistance were measured in situ during irradiation and also the temperature and magnetic field dependence before and after irradiation. Our results show that the transport properties of these materials strongly change at Ga{sup +} fluences much below those used for patterning and ion-beam-induced deposition (IBID), seriously limiting the use of FIB when the intrinsic properties of the materials of interest are of importance. We present a method that can be used to protect the sample as well as to produce selectively irradiation-induced changes.

  13. Correlation between conductivity and prognostic factors in invasive breast cancer using magnetic resonance electric properties tomography (MREPT)

    International Nuclear Information System (INIS)

    Kim, Soo-Yeon; Kim, Min Jung; Kim, Eun-Kyung; Moon, Hee Jung; Yoon, Jung Hyun; Shin, Jaewook; Kim, Dong-Hyun

    2016-01-01

    To investigate the correlation between conductivity and prognostic factors of invasive breast cancer using magnetic resonance electric properties tomography (MREPT). This retrospective study was approved by the Institutional Review Board, and verbal informed consent was obtained prior to breast MRI. This study included 65 women with surgically confirmed invasive breast cancers measuring 1 cm or larger on T2-weighted fast spin echo (FSE). Phase-based MREPT and the coil combination technique were used to reconstruct conductivity. Simple and multiple linear regression analysis were used to find an independent factor associated with conductivity. In total tumours, tumours with HER-2 overexpression showed lower conductivity than those without, and HER-2 overexpression was independently associated with conductivity. In 37 tumours 2 cm or larger, tumours with high mitosis or PR positivity showed higher conductivity than those without, and high mitosis and PR positivity were independently associated with conductivity. In 28 tumours 1-2 cm in size, there were no differences in conductivity according to the prognostic factors. Conductivity values measured using MREPT are associated with the HER-2 overexpression status, and may provide information about mitosis and the PR status of invasive breast cancers 2 cm or larger. (orig.)

  14. Properties of Nb-doped ZnO transparent conductive thin films ...

    Indian Academy of Sciences (India)

    Administrator

    by rf magnetron sputtering using a high quality ceramic target ... Guangxi Key Laboratory of Information Materials, Guilin University of Electronic ... films are highly textured along the c axis and perpendicular to the surface of the substrate. ... ZnO films; Nb-doped; magnetron sputtering; optical and electrical properties. 1.

  15. Conduction band splitting and transport properties of Bi2Se3

    Czech Academy of Sciences Publication Activity Database

    Navrátil, Jiří; Horák, Jaromír; Plecháček, T.; Kamba, Stanislav; Lošťák, P.; Dyck, J. S.; Chen, W.; Uher, C.

    2004-01-01

    Roč. 177, č. 4-5 (2004), s. 1704-1712 ISSN 0022-4596 R&D Projects: GA AV ČR KSK2050602; GA AV ČR KSK1010104 Keywords : transport properties * carrier scattering Subject RIV: CA - Inorganic Chemistry Impact factor: 1.815, year: 2004

  16. 31 CFR 605.1 - Conduct on Bureau of Engraving and Printing property.

    Science.gov (United States)

    2010-07-01

    ... influence of intoxicating beverages, narcotics, hallucinogenic or dangerous drugs, or marijuana, or the consumption of such beverages or the use of such drugs or marijuana in or on the property is prohibited... such directives shall have the same force and effect as if made a part hereof. (m) Weapons and...

  17. Soil physical property estimation from soil strength and apparent electrical conductivity sensor data

    Science.gov (United States)

    Quantification of soil physical properties through soil sampling and laboratory analyses is time-, cost-, and labor-consuming, making it difficult to obtain the spatially-dense data required for precision agriculture. Proximal soil sensing is an attractive alternative, but many currently available s...

  18. Electrokinetic properties and conductance relaxation of polystyrene and silver iodide plugs

    NARCIS (Netherlands)

    Hoven, van den J.J.

    1984-01-01

    This thesis describes an experimental study on the electrokinetic and electrical properties of concentrated polystyrene and silver iodide dispersions. The purpose of the study is to obtain information on the structure of the electrical double layer at the solid-liquid interface. Special

  19. The special features of the crystal structure and properties of oxides with mixed conductivity based on lanthanum gallate

    Science.gov (United States)

    Politova, E. D.; Ivanov, S. A.; Kaleva, G. M.; Mosunov, A. V.; Rusakov, V. S.

    2008-10-01

    The paper presents a review of works on the synthesis, structural composition effects, phase transitions, and electrical conductivity properties of multicomponent solid solutions based on heterosubstituted lanthanum gallate (La,A)(Ga,M)O3 - y . High-temperature phase transitions and structural and charge ordering effects were studied. The presence of iron cations in different valence states was proved; the relative contents of these cations depended on the x parameter and nonstoichiometry parameter y of the base composition. For M = Fe, antiferromagnetic ordering was observed; its temperature interval was determined by the concentration of iron cations in the high-spin state. The total conductivity was found to increase as the concentration of transition metal cations grew because of an increase in the electronic conductivity component. The data on structural parameters and dc and ac conductivity substantiated the conclusion that the highest ionic conductivity and permeability to oxygen were characteristic of iron-containing oxides. The results obtained are evidence that crystal chemical factors play a determining role in the formation of the ion-conducting properties of anion-deficient perovskite-like oxides.

  20. Preparation and Properties of Silver Nanowire-Based Transparent Conductive Composite Films

    Science.gov (United States)

    Tian, Ji-Li; Zhang, Hua-Yu; Wang, Hai-Jun

    2016-06-01

    Silver nanowire-based transparent conductive composite films with different structures were successfully prepared using various methods, including liquid polyol, magnetron sputtering and spin coating. The experimental results revealed that the optical transmittance of all different structural composite films decreased slightly (1-3%) compared to pure films. However, the electrical conductivity of all composite films had a great improvement. Under the condition that the optical transmittance was greater than 78% over the wavelength range of 400-800 nm, the AgNW/PVA/AgNW film became a conductor, while the AZO/AgNW/AZO film and the ITO/AgNW/ITO film showed 88.9% and 94% reductions, respectively, for the sheet resistance compared with pure films. In addition, applying a suitable mechanical pressure can improve the conductivity of AgNW-based composite films.

  1. Thermoelectric properties of conducting polyaniline/BaTiO3 nanoparticle composite films

    Science.gov (United States)

    Anno, H.; Yamaguchi, K.; Nakabayashi, T.; Kurokawa, H.; Akagi, F.; Hojo, M.; Toshima, N.

    2011-05-01

    Conducting polyaniline (PANI)/BaTiO3 nanoparticle composite films with different molar ratio values R=1, 5, 10, and 100 have been prepared on a quartz substrate by casting the m-cresol solution of PANI, (±)-10-camphorsulfonic acid (CSA) and BaTiO3 nanoparticle with an average diameter of about 20 nm. The CSA-doped PANI/BaTiO3 composite films were characterized by x-ray diffraction, Fourier transform infrared spectroscopy, and UV-Vis transmission spectroscopy. The Seebeck coefficient and the electrical conductivity of the films with different R values, together with CSA-doped PANI films, were measured in the temperature range from room temperature to ~400 K. The relation between the Seebeck coefficient and the electrical conductivity in the composite films are discussed from a comparison of them with those of CSA-doped PANI films and other PANI composite films.

  2. The Preparation and Property of Graphene /Tin Oxide Transparent Conductive Film

    Directory of Open Access Journals (Sweden)

    SUN Tao

    2017-02-01

    Full Text Available Graphene doped tin oxide composites were prepared with SnCIZ·2HZ 0 and graphene oxide as raw materials with sol-gel method and then spincoated on the quartz glass to manufacture a new transparent conductive film. The composite film was characterized with X-ray diffraction(XRDand scanning electron microscopy(SEM analysis. XRD results show that the graphene oxide was successfully prepared with Hummers method. The graphene layers and particulate SnOZ can be clearly observed in SEM photos. The transmittance and conductivity of the thin films were tested with ultraviolet visible spectrophotometer and Hall effect measurement. The results show that the transmittivity of composite film in visible region is more than 90% and surface square resistance is 41 S2/口.The graphene/ SnOZ film exhibits a higher performance in transparence and conductivity than commercial FTO glass.

  3. Synthesis, crystal structures, and luminescent properties of Cd(II) coordination polymers assembled from semi-rigid multi-dentate N-containing ligand

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Gang; Shao, Kui-Zhan; Chen, Lei; Liu, Xin-Xin [Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, Jilin (China); Su, Zhong-Min, E-mail: zmsu@nenu.edu.cn [Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, Jilin (China); Ma, Jian-Fang [Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, Jilin (China)

    2012-12-15

    Three new polymers, [Cd(L){sub 2}(H{sub 2}O){sub 2}]{sub n} (1), [Cd{sub 3}(L){sub 2}({mu}{sub 3}-OH){sub 2}({mu}{sub 2}-Cl){sub 2}(H{sub 2}O){sub 2}]{sub n} (2), {l_brace}[Cd{sub 2}(L){sub 2}(nic){sub 2}(H{sub 2}O){sub 2}]{center_dot}H{sub 2}O{r_brace}{sub n} (3) (HL=5-(4-((1H-1,2,4-triazol-1-yl)methyl)phenyl)-1H-tetrazole, Hnic=nicotinic acid) have been prepared and structurally characterized. Compounds 1 and 2 display 2D monomolecular layers built by the inter-linking single helical chains and L{sup -} ligands connecting chain-like [Cd({mu}{sub 3}-OH)({mu}{sub 2}-Cl)]{sub n} secondary building units, respectively. Compound 3 is constructed from the mixed ligands and possesses a (3,4)-connected framework with (4{center_dot}8{sup 2})(4{center_dot}8{sup 2}{center_dot}10{sup 3}) topology. Moreover, the fluorescent properties of HL ligand and compounds 1-3 are also been investigated. - Graphical abstract: Three new coordination polymers based on the semi-rigid multidentate N-donor ligand have been successfully synthesized by hydrothermal reaction. Complexes 1 and 2 exhibit the 2D layers formed by inter-linking single helices and L{sup -} anions bridging 1D chain-like SBUs, respectively. Complex 3 is buit by L{sup -} and assistant nic{sup -} ligands connecting metal centers and possesses a (3,4)-connected framework with (4 Multiplication-Sign 8{sup 2})(4 Multiplication-Sign 8{sup 2} Multiplication-Sign 10{sup 3}) topology. Moreover, these complexes display fluorescent properties indicating that they may have potential applications as optical materials. Highlights: Black-Right-Pointing-Pointer Three Cd-compounds were prepared from semi-rigid HL ligand with different N-containing groups. Black-Right-Pointing-Pointer They exhibit diverse structures from 2D monomolecular layer to 3D covalent framework. Black-Right-Pointing-Pointer The HL ligands displayed various coordination modes under different reaction conditions. Black-Right-Pointing-Pointer These compounds exhibit

  4. Synthesis and characterization of physical properties of Gd{sub 2}O{sub 2}S:Pr{sup 3+} semi-nanoflower phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Bagheri, A.; Rezaee Ebrahim Saraee, Kh.; Shakur, H.R. [University of Isfahan, Department of Nuclear Engineering, Faculty of Advance Sciences and Technologies, Isfahan (Iran, Islamic Republic of); Zamani Zeinali, H. [Nuclear Science and Technology Research Institute, Agriculture, Medical and Industrial Research School, Karaj (Iran, Islamic Republic of)

    2016-05-15

    Pure gadolinium oxysulfide phosphor (Gd{sub 2}O{sub 2}S) and trivalent praseodymium-doped gadolinium oxysulfide phosphor (Gd{sub 2}O{sub 2}S:Pr{sup 3+}) scintillators with semi-nanoflower crystalline structures were successfully synthesized through a precipitation method and subsequent calcination treatment as a converter for X-ray imaging detectors. The characterization such as the crystal structures and nanostructure of Gd{sub 2}O{sub 2}S:Pr{sup 3+} scintillator measured by XRD and FeE-SEM experiment. The optical properties of Gd{sub 2}O{sub 2}S:Pr{sup 3+} scintillator were studied. Luminescence spectra of Gd{sub 2}O{sub 2}S:Pr{sup 3+} under 320 nm UV excitation show a green emission at near 511 nm corresponding to the {sup 3}P{sub 0}-{sup 3}H{sub 4} of Pr ions. After scintillation properties of synthesized Gd{sub 2}O{sub 2}S:Pr{sup 3+} scintillator investigated, Gd{sub 2}O{sub 2}S:Pr{sup 3+} scintillating film fabricated on a glass substrate by a sedimentation method. X-ray imaging of the fabricated scintillators confirmed that the Gd{sub 2}O{sub 2}S:Pr{sup 3+} scintillator could be used for radiography applications in which good spatial resolution is needed. (orig.)

  5. Chain conformation, rheological and charge properties of fucoidan extracted from sea cucumber Thelenota ananas: A semi-flexible coil negative polyelectrolyte.

    Science.gov (United States)

    Xu, Xiaoqi; Xue, Changhu; Chang, Yaoguang; Liu, Guanchen

    2017-12-15

    As a bioactive and functional polysaccharide, sea cucumber fucoidan has received increasing attention. Chain conformation and physicochemical properties of fucoidan extracted from Thelenota ananas (Ta-FUC) was investigated by utilizing HPSEC-MALLS-Visc-RI, microelectrophoresis and steady shear measurements. The conformation parameter α s (0.61±0.02), the Mark-Houwink-Kuhn-Sakurada exponent α η (0.92±0.01), α h (0.64±0.01) and the Smidsrød-Haug stiffness parameter B (0.036±0.010) consistently manifested that Ta-FUC adopted a semi-flexible coil conformation in NaCl solution. Based on a wormlike cylinder model, stiffness parameters, including persistence length q (13.27±0.80nm) and cylinder diameter d (0.79nm), were calculated. This polysaccharide demonstrated shear-thinning rheological behaviour, and critical concentration from dilute to semidilute concentration regime was determined as 3.6mg/ml. Ta-FUC exhibited as a negative polyelectrolyte in wide pH and ionic strength ranges. These molecular characteristics and physicochemical properties would facilitate further application of Ta-FUC as a functional ingredient in food. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. A synthesis of light absorption properties of the Pan-Arctic Ocean: application to semi-analytical estimates of dissolved organic carbon concentrations from space

    Science.gov (United States)

    Matsuoka, A.; Babin, M.; Doxaran, D.; Hooker, S. B.; Mitchell, B. G.; Bélanger, S.; Bricaud, A.

    2013-11-01

    The light absorption coefficients of particulate and dissolved materials are the main factors determining the light propagation of the visible part of the spectrum and are, thus, important for developing ocean color algorithms. While these absorption properties have recently been documented by a few studies for the Arctic Ocean (e.g., Matsuoka et al., 2007, 2011; Ben Mustapha et al., 2012), the datasets used in the literature were sparse and individually insufficient to draw a general view of the basin-wide spatial and temporal variations in absorption. To achieve such a task, we built a large absorption database at the pan-Arctic scale by pooling the majority of published datasets and merging new datasets. Our results showed that the total non-water absorption coefficients measured in the Eastern Arctic Ocean (EAO; Siberian side) are significantly higher than in the Western Arctic Ocean (WAO; North American side). This higher absorption is explained by higher concentration of colored dissolved organic matter (CDOM) in watersheds on the Siberian side, which contains a large amount of dissolved organic carbon (DOC) compared to waters off North America. In contrast, the relationship between the phytoplankton absorption (aφ(λ)) and chlorophyll a (chl a) concentration in the EAO was not significantly different from that in the WAO. Because our semi-analytical CDOM absorption algorithm is based on chl a-specific aφ(λ) values (Matsuoka et al., 2013), this result indirectly suggests that CDOM absorption can be appropriately derived not only for the WAO but also for the EAO using ocean color data. Derived CDOM absorption values were reasonable compared to in situ measurements. By combining this algorithm with empirical DOC vs. CDOM relationships, a semi-analytical algorithm for estimating DOC concentrations for coastal waters at the Pan-Arctic scale is presented and applied to satellite ocean color data.

  7. Soil quality evaluation following the implementation of permanent cover crops in semi-arid vineyards. Organic matter, physical and biological soil properties

    Energy Technology Data Exchange (ETDEWEB)

    Virto, I.; Imaz, M. J.; Fernandez-Ugalde, O.; Urrutia, I.; Enrique, A.; Bescansa, P.

    2012-07-01

    Changing from conventional vineyard soil management, which includes keeping bare soil through intense tilling and herbicides, to permanent grass cover (PGC) is controversial in semi-arid land because it has agronomic and environmental advantages but it can also induce negative changes in the soil physical status. The objectives of this work were (i) gaining knowledge on the effect of PGC on the soil physical and biological quality, and (ii) identifying the most suitable soil quality indicators for vineyard calcareous soils in semi-arid land. Key soil physical, organic and biological characteristics were determined in a Cambic Calcisol with different time under PGC (1 and 5 years), and in a conventionally managed control. Correlation analysis showed a direct positive relationship between greater aggregate stability (WSA), soil-available water capacity (AWC), microbial biomass and enzymatic activity in the topsoil under PGC. Total and labile organic C concentrations (SOC and POM-C) were also correlated to microbial parameters. Factor analysis of the studied soil attributes using principal component analysis (PCA) was done to identify the most sensitive soil quality indicators. Earthworm activity, AWC, WSA, SOC and POM-C were the soil attributes with greater loadings in the two factors determined by PCA, which means that these properties can be considered adequate soil quality indicators in this agrosystem. These results indicate that both soil physical and biological attributes are different under PGC than in conventionally-managed soils, and need therefore to be evaluated when assessing the consequences of PGC on vineyard soil quality. (Author) 65 refs.

  8. A Synthesis of Light Absorption Properties of the Arctic Ocean: Application to Semi-analytical Estimates of Dissolved Organic Carbon Concentrations from Space

    Science.gov (United States)

    Matsuoka, A.; Babin, M.; Doxaran, D.; Hooker, S. B.; Mitchell, B. G.; Belanger, S.; Bricaud, A.

    2014-01-01

    The light absorption coefficients of particulate and dissolved materials are the main factors determining the light propagation of the visible part of the spectrum and are, thus, important for developing ocean color algorithms. While these absorption properties have recently been documented by a few studies for the Arctic Ocean [e.g., Matsuoka et al., 2007, 2011; Ben Mustapha et al., 2012], the datasets used in the literature were sparse and individually insufficient to draw a general view of the basin-wide spatial and temporal variations in absorption. To achieve such a task, we built a large absorption database at the pan-Arctic scale by pooling the majority of published datasets and merging new datasets. Our results showed that the total non-water absorption coefficients measured in the Eastern Arctic Ocean (EAO; Siberian side) are significantly higher 74 than in the Western Arctic Ocean (WAO; North American side). This higher absorption is explained 75 by higher concentration of colored dissolved organic matter (CDOM) in watersheds on the Siberian 76 side, which contains a large amount of dissolved organic carbon (DOC) compared to waters off 77 North America. In contrast, the relationship between the phytoplankton absorption (a()) and chlorophyll a (chl a) concentration in the EAO was not significantly different from that in the WAO. Because our semi-analytical CDOM absorption algorithm is based on chl a-specific a() values [Matsuoka et al., 2013], this result indirectly suggests that CDOM absorption can be appropriately erived not only for the WAO but also for the EAO using ocean color data. Derived CDOM absorption values were reasonable compared to in situ measurements. By combining this algorithm with empirical DOC versus CDOM relationships, a semi-analytical algorithm for estimating DOC concentrations for coastal waters at the Pan-Arctic scale is presented and applied to satellite ocean color data.

  9. Macrophysical and optical properties of mid-latitude cirrus clouds over a semi-arid area observed by micro-pulse lidar

    International Nuclear Information System (INIS)

    Wang, Jin; Zhang, Lei; Huang, Jianping; Cao, Xianjie; Liu, Ruijin; Zhou, Bi; Wang, Hongbin; Huang, Zhongwei; Bi, Jianrong; Zhou, Tian; Zhang, Beidou; Wang, Tengjiao

    2013-01-01

    Macrophysical and optical characteristics of cirrus clouds were investigated at the Semi-Arid Climate Observatory and Laboratory (SACOL; 35.95°N, 104.14°E) of Lanzhou University in northwest China during April to December 2007 using micro-pulse lidar data and profiling radiometer measurements. Analysis of the measurements allowed the determination of macrophysical properties such as cirrus cloud height, ambient temperature, and geometrical depth, and optical characteristics were determined in terms of optical depth, extinction coefficient, and lidar ratio. Cirrus clouds were generally observed at heights ranging from 5.8 to 12.7 km, with a mean of 9.0±1.0 km. The mean cloud geometrical depth and optical depth were found to be 2.0±0.6 km and 0.350±0.311, respectively. Optical depth increased linearly with increasing geometrical depth. The results derived from lidar signals showed that cirrus over SACOL consisted of thin cirrus and opaque cirrus which occurred frequently in the height of 8–10 km. The lidar ratio varied from 5 to 70 sr, with a mean value of 26±16 sr, after taking into account multiple scattering effects. The mean lidar ratio of thin cirrus was greater than that of opaque cirrus. The maximum lidar ratio appeared between 0.058 and 0.3 when plotted against optical depth. The lidar ratio increased exponentially as the optical depth increased. The maximum lidar ratio fell between 11 and 12 km when plotted against cloud mid-height. The lidar ratio first increased and then decreased with increasing mid-height. -- Highlights: ► Cirrus clouds over semi-arid area were firstly observed by ground-based lidar. ► Macrophysical and optical characteristics of cirrus clouds were discussed. ► Thin cirrus and opaque cirrus occurred most frequently over SACOL. ► Thin cirrus often occurred above 10 km

  10. Crystal structure and ion conducting properties of La5NbMo2O16

    KAUST Repository

    Vu, T.D.; Krichen, F.; Barre, M.; Busselez, R.; Adil, Karim; Jouanneaux, A.; Suard, E.; Goutenoire, F.

    2016-01-01

    .2250(1) Å. La5NbMo2O16 is a new analogue of the R5Mo3O16 series (R=Pr, Nd). The structure was refined from a combined data X-ray and neutron powder diffraction. The ionic conductivity of the compound is then measured on sintered pellets, by means of complex

  11. Structure and conductive properties of poly(ethylene oxide)/layered double hydroxide nanocomposite polymer electrolytes

    International Nuclear Information System (INIS)

    Liao, C.-S.; Ye, W.-B.

    2004-01-01

    The oligo(ethylene oxide) modified layered double hydroxide (LDH) prepared by template method was added as a nanoscale nucleating agent into poly(ethylene oxide) (PEO) to form PEO/OLDH nanocomposite electrolytes. The effects of OLDH addition on morphology and conductivities of nanocomposite electrolytes were studied using wide-angle X-ray diffractometer, polarized optical microscopy, differential scanning calorimetry and ionic conductivity measurement. The results show that the exfoliated morphology of nanocomposites is formed due to the surface modification of LDH layers with PEO matrix compatible oligo(ethylene oxide)s. The nanoscale dispersed OLDH layers inhibit the crystal growth of PEO crystallites and result in a plenty amount of intercrystalline grain boundary within PEO/OLDH nanocomposites. The ionic conductivities of nanocomposite electrolytes are enhanced by three orders of magnitude compared to the pure PEO polymer electrolytes at ambient temperature. It can be attributed to the ease transport of Li + along intercrystalline amorphous phase. This novel nanocomposite electrolytes system with high conductivities will be benefited to fabricate the thin-film type of Li-polymer secondary battery

  12. The role of the salt electrolyt on the electrical conductive properties of a polymeric bipolar membrane

    NARCIS (Netherlands)

    Alcaraz, Antonio; Wilhelm, F.G.; Wessling, Matthias; Ramirez, Patricio

    2001-01-01

    We have studied the contribution of the salt electrolyte to the electrical conductive characteristics of a bipolar membrane. We present first a critical analysis of previous theoretical approaches, and discuss the limits of validity. Experimental current-voltage curves of several commercial bipolar

  13. Electrical conductivity and dielectric properties of TlInS2 single crystals

    Science.gov (United States)

    El-Nahass, M. M.; Youssef, S. B.; Ali, H. A. M.; Hassan, A.

    2011-07-01

    TlInS2 single crystals were grown by using Bridgman-Stockbauer technique. Measurements of DC conductivity were carried out in parallel (σ//) and perpendicular (σ⊥) directions to the c-axis over a temperature range from 303 to 463 K. The anisotropic behaviour of the electrical conductivity was also detected. AC conductivity and dielectric measurements were studied as a function of both frequency (102-106 Hz) and temperature (297-375 K). The frequency dependence of the AC conductivity revealed that σac(ω) obeys the universal law: σac(ω) = Aωs. The mechanism of the ac charge transport across the layers of TlInS2 single crystals was referred to the hopping over localized states near the Fermi level in the frequency range >3.5 × 103 Hz. The temperature dependence of σac(ω) for TlInS2 showed that σac is thermally activated process. Both of ɛ1 and ɛ2 decrease by increasing frequency and increase by increasing temperature. Some parameters were calculated as: the density of localized states near the Fermi level NF = 1.5 × 1020 eV-1 cm-3, the average time of charge carrier hoping between localized states τ = 3.79 μs and the average hopping distance R = 6.07 nm.

  14. Synthesis of rock-salt type lithium borohydride and its peculiar Li+ ion conduction properties

    Directory of Open Access Journals (Sweden)

    R. Miyazaki

    2014-05-01

    Full Text Available The high energy density and excellent cycle performance of lithium ion batteries makes them superior to all other secondary batteries and explains why they are widely used in portable devices. However, because organic liquid electrolytes have a higher operating voltage than aqueous solution, they are used in lithium ion batteries. This comes with the risk of fire due to their flammability. Solid electrolytes are being investigated to find an alternative to organic liquid. However, the nature of the solid-solid point contact at the interface between the electrolyte and electrode or between the electrolyte grains is such that high power density has proven difficult to attain. We develop a new method for the fabrication of a solid electrolyte using LiBH4, known for its super Li+ ion conduction without any grain boundary contribution. The modifications to the conduction pathway achieved by stabilizing the high pressure form of this material provided a new structure with some LiBH4, more suitable to the high rate condition. We synthesized the H.P. form of LiBH4 under ambient pressure by doping LiBH4 with the KI lattice by sintering. The formation of a KI - LiBH4 solid solution was confirmed both macroscopically and microscopically. The obtained sample was shown to be a pure Li+ conductor despite its small Li+ content. This conduction mechanism, where the light doping cation played a major role in ion conduction, was termed the “Parasitic Conduction Mechanism.” This mechanism made it possible to synthesize a new ion conductor and is expected to have enormous potential in the search for new battery materials.

  15. Influence of sputtering gas pressure on properties of transparent conducting Si-doped zinc oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Hua; Liu, Hunfa; Lei, Chengxin [Shandong Univ. of Technology, Zibo (China). Dept. of Sciences

    2013-10-15

    Si-doped zinc oxide (SZO, Si 3%) thin films were deposited on glass substrates by means of direct current magnetron sputtering under different pressures. The influence of sputtering pressure on structure, morphology, optical and electrical properties of SZO thin films was investigated. The results reveal that the sputtering pressures have a significant impact on the growth rate, crystal quality and electrical properties of the films, but have little impact on the optical properties of the films. SZO thin film samples grown on glasses are polycrystalline with a hexagonal wurtzite structure and have a preferred orientation along the c-axis perpendicular to the substrate. When the sputtering pressure increases from 2 to 8 Pa, the film surface becomes compact and smooth, the degree of crystallization of the films increases, and the resistivity of films decreases. However, when the sputtering pressure continues to increase from 8 to 10 Pa, the degree of crystallization of the films decreases, the grain size decreases, and the resistivity of the films increases. SZO(3%) thin film deposited at a sputtering pressure of 8 Pa shows the largest carrier concentration, the largest mobility, the lowest resistivity of 3.0 x 10{sup -4} {Omega} cm and a high overall transmission of 93.3% in the visible range. (orig.)

  16. A parametric study on hydraulic conductivity and self-healing properties of geotextile clay liners used in landfills.

    Science.gov (United States)

    Parastar, Fatemeh; Hejazi, Sayyed Mahdi; Sheikhzadeh, Mohammad; Alirezazadeh, Azam

    2017-11-01

    Nowadays, the raise of excessive generation of solid wastes is considered as a major environmental concern due to the fast global population growth. The contamination of groundwater from landfill leachate compromises every living creature. Geotextile clay liner (GCL) that has a sandwich structure with two fibrous sheets and a clay core can be considered as an engineered solution to prevent hazardous pollutants from entering into groundwater. The main objective of the present study is therefore to enhance the performance of GCL structures. By changing some structural factors such as clay type (sodium vs. calcium bentonite), areal density of clay, density of geotextile, geotextile thickness, texture type (woven vs. nonwoven), and needle punching density a series of GCL samples were fabricated. Water pressure, type of cover soil and overburden pressure were the environmental variables, while the response variables were hydraulic conductivity and self-healing rate of GCL. Rigid wall constant head permeability test was conducted on all the samples. The outlet water flow was measured and evaluated at a defined time period and the hydraulic conductivity was determined for each sample. In the final stage, self-healing properties of samples were investigated and an analytical model was used to explain the results. It was found that higher Montmorillonite content of clay, overburden pressure, needle punching density and areal density of clay poses better self-healing properties and less hydraulic conductivity, meanwhile, an increase in water pressure increases the hydraulic conductivity. Moreover, the observations were aligned with the analytical model and indicated that higher fiber inclusion as a result of higher needle-punching density produces closer contact between bentonite and fibers, reduces hydraulic conductivity and increases self-healing properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Finite-Element Analysis of Crack Arrest Properties of Fiber Reinforced Composites Application in Semi-Elliptical Cracked Pipelines

    Science.gov (United States)

    Wang, Linyuan; Song, Shulei; Deng, Hongbo; Zhong, Kai

    2018-04-01

    In nowadays, repair method using fiber reinforced composites as the mainstream pipe repair technology, it can provide security for X100 high-grade steel energy long-distance pipelines in engineering. In this paper, analysis of cracked X100 high-grade steel pipe was conducted, simulation analysis was made on structure of pipes and crack arresters (CAs) to obtain the J-integral value in virtue of ANSYS Workbench finite element software and evaluation on crack arrest effects was done through measured elastic-plastic fracture mechanics parameter J-integral and the crack arrest coefficient K, in a bid to summarize effect laws of composite CAs and size of pipes and cracks for repairing CAs. The results indicate that the K value is correlated with laying angle λ, laying length L2/D1, laying thickness T1/T2of CAs, crack depth c/T1 and crack length a/c, and calculate recommended parameters for repairing fiber reinforced composite CAs in terms of two different crack forms.

  18. Effect of epoxidation level on thermal properties and ionic conductivity of epoxidized natural rubber solid polymer nanocomposite electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Harun, Fatin; Chan, Chin Han; Winie, Tan [Faculty of Applied Sciences, UniversitiTeknologi MARA (UiTM), Shah Alam, 40450 Selangor Darul Ehsan (Malaysia); Sim, Lai Har; Zainal, Nurul Fatahah Asyqin [Center of Foundation Studies, PuncakAlam Campus, UniversitiTeknologi MARA, 40430 Selangor Darul Ehsan (Malaysia)

    2015-08-28

    Effect of epoxide content on the thermal and conductivity properties of epoxidized natural rubber (ENR) solid polymer nanocomposite electrolytes was investigated. Commercial available epoxidized natural rubber having 25 (ENR25) and 50 mole% (ENR50) epoxide, respectively were incorporated with lithium perchlorate (LiClO{sub 4}) salt and titanium dioxide (TiO{sub 2}) nanofiller via solution casting method. The solid polymer nanocomposite electrolytes were characterized by differential scanning calorimetry (DSC) and impedance spectroscopy (IS) for their thermal properties and conductivity, respectively. It was evident that introduction of LiClO{sub 4} causes a greater increase in glass transition temperature (T{sub g}) and ionic conductivity of ENR50 as compared to ENR25. Upon addition of TiO{sub 2} in ENR/LiClO{sub 4} system, a remarkable T{sub g} elevation was observed for both ENRs where ENR50 reveals a more pronounced changes. It is interesting to note that they exhibit different phenomenon in ionic conductivity with TiO{sub 2} loading where ENR25 shows enhancement of conductivity while ENR50 shows declination.

  19. Effect of electrical conductivity on the polarization behaviour and pyroelectric, piezoelectric property prediction of 0-3 ferroelectric composites

    International Nuclear Information System (INIS)

    Wei Nian; Zhang Duanming; Yang Fengxia; Han Xiangyun; Zhong Zhicheng; Zheng Keyu

    2007-01-01

    We have investigated the effect of electrical conductivity of the constituents on the poling behaviour of the ceramic inclusions in 0-3 ferroelectric composites which comprise a dilute suspension of spherical particles uniformly distributed in the matrix material. A new model for the pyroelectric and piezoelectric properties in terms of the poling conditions (poling field and poling time) has been developed to include electrical conductivity. Simulated results show that conductivity plays an important role in the poling process. Properly increasing the conductivity of the matrix σ m can enhance the polarization in the ceramic inclusion of the composite P i , thereby making the poling of the composite more efficient. In contrast, higher conductivity of the ceramic inclusion σ i results in lower polarization P i , which is unfavourable to the poling of the composite. These results provide insights into the observed behaviour of 0-3 composites. The model predicts the pyroelectric and piezoelectric properties under different poling conditions, which agree well with the corresponding experimental data

  20. Effect of helium gas pressure on dc conduction mechanism and EMI shielding properties of nanocrystalline carbon thin films

    Energy Technology Data Exchange (ETDEWEB)

    Rawal, Ishpal, E-mail: rawalishpal@gmail.com [Department of Physics, Kirori Mal College, University of Delhi, Delhi 110007 (India); Panwar, O.S., E-mail: ospanwar@mail.nplindia.ernet.in [Polymorphic Carbon Thin Films Group, Physics of Energy Harvesting Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012 (India); Tripathi, R.K. [Polymorphic Carbon Thin Films Group, Physics of Energy Harvesting Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012 (India); Singh, Avanish Pratap; Dhawan, S.K. [Polymeric and Soft Materials Group, Physics Engineering of Carbon, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012 (India); Srivastava, A.K. [Electron and Ion Microscopy, Sophisticated and Analytical Instruments, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012 (India)

    2015-05-05

    This paper reports the effect of helium partial pressures ∼1.2 × 10{sup −5} (base pressure), 1.4 × 10{sup −4}, 8.6 × 10{sup −3} and 0.1 mbar on the variable range hopping conduction in nanocrystalline carbon thin films deposited by filtered cathodic jet carbon arc technique. High resolution transmission electron microscopy studies suggest the random distribution of nanocrystallites (∼3–7 nm) in the amorphous matrix. The DC conduction behavior of the deposited nanocrystalline films has been studied in the light of Mott's variable range hopping (VRH) model and found to obey three dimensional VRH conduction. The randomly distributed nanocrystallites in amorphous matrix may lead to change in the distribution of density of states near Fermi level and hence, the conduction behavior. The enhanced electrical conductivity of the deposited films due to the helium environment makes them suitable for electromagnetic interference shielding applications. The sample deposited at a helium partial pressure of 0.1 mbar has a value of shielding effectiveness ∼7.84 dB at 18 GHz frequency. - Highlights: • Nanocrystalline carbon thin films (NCTF) has been deposited by FCJCA technique. • Effect of helium gas pressure has been studied on the properties of NCTF. • Investigation of EMI shielding properties of NCTF has been carried out.

  1. Crystal structure and ion conducting properties of La5NbMo2O16

    KAUST Repository

    Vu, T.D.

    2016-01-29

    The new compound La5NbMo2O16 with high ionic conduction has been discovered during the study of the ternary phase diagram of La2O3-MoO3-Nb2O5. The material crystallizes in the cubic space group Pn 3n (no 222) with the unit cell parameter a=11.2250(1) Å. La5NbMo2O16 is a new analogue of the R5Mo3O16 series (R=Pr, Nd). The structure was refined from a combined data X-ray and neutron powder diffraction. The ionic conductivity of the compound is then measured on sintered pellets, by means of complex impedance spectroscopy. © 2016 Elsevier Inc. All rights reserved.

  2. Conductivity and electrical properties of corn starch-chitosan blend biopolymer electrolyte incorporated with ammonium iodide

    Science.gov (United States)

    Yusof, Y. M.; Shukur, M. F.; Illias, H. A.; Kadir, M. F. Z.

    2014-03-01

    This work focuses on the characteristics of polymer blend electrolytes based on corn starch and chitosan doped with ammonium iodide (NH4I). The electrolytes were prepared using the solution cast method. A polymer blend comprising 80 wt% starch and 20 wt% chitosan was found to be the most amorphous blend and suitable to serve as the polymer host. Fourier transform infrared spectroscopy analysis proved the interaction between starch, chitosan and NH4I. The highest room temperature conductivity of (3.04 ± 0.32) × 10-4 S cm-1 was obtained when the polymer host was doped with 40 wt% NH4I. This result was further proven by field emission scanning electron microscopy study. All electrolytes were found to obey the Arrhenius rule. Dielectric studies confirm that the electrolytes obeyed non-Debye behavior. The temperature dependence of the power law exponent s for the highest conducting sample follows the quantum mechanical tunneling model.

  3. On the effect of ammonia and wet atmospheres on the conducting properties of different lutetium bisphthalocyanine thin films

    International Nuclear Information System (INIS)

    Parra, Vicente; Bouvet, Marcel; Brunet, Jerome; Rodriguez-Mendez, Maria Luz; Saja, Jose Antonio de

    2008-01-01

    In this article, we present new experimental data regarding the influence of ammonia (NH 3 ) and water (from wet atmospheres) in the conducting properties of lutetium bisphthalocyanine (LuPc 2 )-based films in two very different structural features, namely Langmuir-Blodgett (LB) and vacuum evaporated (VE) films, deposited onto interdigitated electrodes. We pay particular attention to the effect of the mass flow rate ratios of the active gases, which certainly influence the mechanism of conduction of the chemiresistors. The particular trends observed are discussed on the basis of two main contributions: the electronic effects and the competition between gases in the adsorption process

  4. On the effect of ammonia and wet atmospheres on the conducting properties of different lutetium bisphthalocyanine thin films

    Energy Technology Data Exchange (ETDEWEB)

    Parra, Vicente [Ecole Superieure de Physique et Chimie Industrielles (ESPCI) and Laboratoire de Chimie Inorganique et Materiaux Moleculaires-CNRS UMR 7071, Universite Pierre et Marie Curie (Paris 6) (France); Bouvet, Marcel [Ecole Superieure de Physique et Chimie Industrielles (ESPCI) and Laboratoire de Chimie Inorganique et Materiaux Moleculaires-CNRS UMR 7071, Universite Pierre et Marie Curie (Paris 6) (France)], E-mail: marcel.bouvet@espci.fr; Brunet, Jerome [Universite Blaise Pascal, LASMEA-CNRS UMR 6602, Clermont-Ferrand (France); Rodriguez-Mendez, Maria Luz [Dept. Quimica Fisica y Quimica Inorganica, Escuela Tecnica Superior de Ingenieros Industriales (E.T.S.I.I), Universidad de Valladolid (Spain); Saja, Jose Antonio de [Dept. Fisica de la Materia Condensada, Facultad de Ciencias, Universidad de Valladolid (Spain)

    2008-10-31

    In this article, we present new experimental data regarding the influence of ammonia (NH{sub 3}) and water (from wet atmospheres) in the conducting properties of lutetium bisphthalocyanine (LuPc{sub 2})-based films in two very different structural features, namely Langmuir-Blodgett (LB) and vacuum evaporated (VE) films, deposited onto interdigitated electrodes. We pay particular attention to the effect of the mass flow rate ratios of the active gases, which certainly influence the mechanism of conduction of the chemiresistors. The particular trends observed are discussed on the basis of two main contributions: the electronic effects and the competition between gases in the adsorption process.

  5. Mechanical property and conductivity changes in several copper alloys after 13.5 dpa neutron irradiation

    International Nuclear Information System (INIS)

    Ames, M.; Kohse, G.; Lee, T.S.; Grant, N.J.; Harling, O.K.

    1986-01-01

    A scoping experiment in which 25 different copper materials of 17 alloy compositions were irradiated to approx.13.5 dpa approx.400 0 C in a fast reactor is described. The materials include rapidly solidified (RS) alloys, with and without oxide dispersion strengthening, as well as conventionally processed alloys. Immersion density (swelling), electrical conductivity (which can be related to thermal conductivity), and yield stress and ductility by miniature disk bend testing have been measured before and after irradiation. It was found, in general, that the Rs alloys are stable under irradiation to 13.5 dpa, showing small conductivity changes and little or no swelling. Reduction of strength and ductility, in post-irradiation tests at the irradiation temperature, are not generally observed. Some conventionally processed alloys also performed well, although irradiation softening and swelling of several percent were observed in some cases, and pure copper swelled in excess of 5%. It is concluded that a number of copper alloys should receive further study, and that higher dose irradiations will be required to establish the limits of swelling suppression in these alloys

  6. Novel electrical conductivity properties in Ca-doped BiFeO3 nanoparticles

    International Nuclear Information System (INIS)

    Wang, X.; Wang, S. Y.; Liu, W. F.; Xi, X. J.; Zhang, H.; Guo, F.; Xu, X. L.; Li, M.; Liu, L.; Zhang, C.; Li, X.; Yang, J. B.

    2015-01-01

    The charge defective structure in Bi 1−x Ca x FeO 3 (CBFO, x = 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3) nanoparticles (NPs) ranging from 140 to 25 nm as well as their relations to band gap and leakage current behavior are investigated. It is demonstrated that Ca doping effectively narrows the band gap from ∼2.16 to ∼2.02 eV, due to the appearance and accumulation of oxygen vacancy. Subsequently, enhanced electrical conductivity was obtained in these CBFO NPs, which leads to the appearance of a distinct threshold switching behavior in Ca-doped BFO NPs with higher conductivity at room temperature. Possible mechanisms for Ca doping effects on the electric conduction were discussed upon the interplay of NPs’ size effect and mobile charged defects on the basis of reduced particle size and the increased density of oxygen vacancy analyzed through X-ray photoelectron spectrum

  7. Novel electrical conductivity properties in Ca-doped BiFeO{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.; Wang, S. Y., E-mail: shouyu.wang@yahoo.com [Tianjin Normal University, College of Physics and Materials Science (China); Liu, W. F., E-mail: wfliu@tju.edu.cn [Tianjin University, Department of Applied Physics, Institute of Advanced Materials Physics, Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Faculty of Science (China); Xi, X. J. [Tianjin Normal University, College of Physics and Materials Science (China); Zhang, H. [Tianjin University, Department of Applied Physics, Institute of Advanced Materials Physics, Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Faculty of Science (China); Guo, F. [Tianjin Normal University, College of Physics and Materials Science (China); Xu, X. L. [Tianjin University, Department of Applied Physics, Institute of Advanced Materials Physics, Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Faculty of Science (China); Li, M.; Liu, L.; Zhang, C.; Li, X.; Yang, J. B. [Tianjin Normal University, College of Physics and Materials Science (China)

    2015-05-15

    The charge defective structure in Bi{sub 1−x}Ca{sub x}FeO{sub 3} (CBFO, x = 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3) nanoparticles (NPs) ranging from 140 to 25 nm as well as their relations to band gap and leakage current behavior are investigated. It is demonstrated that Ca doping effectively narrows the band gap from ∼2.16 to ∼2.02 eV, due to the appearance and accumulation of oxygen vacancy. Subsequently, enhanced electrical conductivity was obtained in these CBFO NPs, which leads to the appearance of a distinct threshold switching behavior in Ca-doped BFO NPs with higher conductivity at room temperature. Possible mechanisms for Ca doping effects on the electric conduction were discussed upon the interplay of NPs’ size effect and mobile charged defects on the basis of reduced particle size and the increased density of oxygen vacancy analyzed through X-ray photoelectron spectrum.

  8. Silver nanowire based flexible electrodes with improved properties: High conductivity, transparency, adhesion and low haze

    International Nuclear Information System (INIS)

    Kiran Kumar, A.B.V.; Wan Bae, Chang; Piao, Longhai; Kim, Sang-Ho

    2013-01-01

    Graphical abstract: This graphical abstract illustrates the schematic representation of the main drawbacks and rectifications for AgNWs based transparent electrodes. - Highlights: • Films exhibited low sheet resistance and optical properties with R s ≤ 30 Ω/□ and T ≥ 90%. • We decreased haze to 2% by controlling AgNWs length, diameter, and concentration. • We achieved good adhesion for AgNWs on PET film. • There is no significant change in resistance in the bending angle from 0° to 180°, and on twisting. - Abstract: Recent work has been focusing on solution processable transparent electrodes for various applications including solar cells and displays. As well as, the research aims majorly at silver nanowires (AgNWs) to replace ITO. We enhance the transparent electrode performance as a function of optical and mechanical properties with low sheet resistance, by controlling the AgNWs accept ratios, ink composition, and processing conditions. The nanowire network of transparent films agrees with the 2D percolation law. The film transmittance values at 550 nm are coping with a reference ITO film. Sheet resistance and haze values are suitable for flexible electronic applications. We fabricate transparent flexible film using a low-cost processing technique

  9. Silver nanowire based flexible electrodes with improved properties: High conductivity, transparency, adhesion and low haze

    Energy Technology Data Exchange (ETDEWEB)

    Kiran Kumar, A.B.V.; Wan Bae, Chang; Piao, Longhai, E-mail: piaolh@kongju.ac.kr; Kim, Sang-Ho, E-mail: sangho1130@kongju.ac.kr

    2013-08-01

    Graphical abstract: This graphical abstract illustrates the schematic representation of the main drawbacks and rectifications for AgNWs based transparent electrodes. - Highlights: • Films exhibited low sheet resistance and optical properties with R{sub s} ≤ 30 Ω/□ and T ≥ 90%. • We decreased haze to 2% by controlling AgNWs length, diameter, and concentration. • We achieved good adhesion for AgNWs on PET film. • There is no significant change in resistance in the bending angle from 0° to 180°, and on twisting. - Abstract: Recent work has been focusing on solution processable transparent electrodes for various applications including solar cells and displays. As well as, the research aims majorly at silver nanowires (AgNWs) to replace ITO. We enhance the transparent electrode performance as a function of optical and mechanical properties with low sheet resistance, by controlling the AgNWs accept ratios, ink composition, and processing conditions. The nanowire network of transparent films agrees with the 2D percolation law. The film transmittance values at 550 nm are coping with a reference ITO film. Sheet resistance and haze values are suitable for flexible electronic applications. We fabricate transparent flexible film using a low-cost processing technique.

  10. Optoelectronic properties of sprayed transparent and conducting indium doped zinc oxide thin films

    International Nuclear Information System (INIS)

    Shinde, S S; Shinde, P S; Bhosale, C H; Rajpure, K Y

    2008-01-01

    Indium doped zinc oxide (IZO) thin films are grown onto Corning glass substrates using the spray pyrolysis technique. The effect of doping concentration on the structural, electrical and optical properties of IZO thin films is studied. X-ray diffraction studies show a change in preferential orientation from the (0 0 2) to the (1 0 1) crystal planes with increase in indium doping concentration. Scanning electron microscopy studies show polycrystalline morphology of the films. Based on the Hall-effect measurements and analysis, impurity scattering is found to be the dominant mechanism determining the diminished mobility in ZnO thin films having higher indium concentration. The addition of indium also induces a drastic decrease in the electrical resistivity of films; the lowest resistivity (4.03 x 10 -5 Ω cm) being observed for the film deposited with 3 at% indium doping. The effect of annealing on the film properties has been reported. Films deposited with 3 at% In concentration have relatively low resistivity with 90% transmittance at 550 nm and the highest value of figure of merit 7.9 x 10 -2 □ Ω -1

  11. Electronic properties of polyamide-PPy/metal junction and electrical conductivity of a typical sample at low temperatures

    International Nuclear Information System (INIS)

    Suenel, N.; Sedef, A.G.; Parlak, M.; Toppare, L.

    2005-01-01

    Electronic properties of junctions fabricated by polyamide-polypyrrole composite films polymerized with adjusted doping concentration and various metal contacts (In, Al, Au and Ag) were investigated. For the junctions giving good rectification I 0 , n and φ b were specified. Conductivity of polyamide-polypyrrole composite polymer was obtained as a function of temperature in the 70-320 K range and was found to obey the VRH model. In addition the Mott parameters were evaluated

  12. Electronic properties of polyamide-PPy/metal junction and electrical conductivity of a typical sample at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Suenel, N. [Gaziosmanpasa University, Physics Department, Tasliciftlik Kampasu, Tokat (Turkey)]. E-mail: nsunel@gop.edu.tr; Sedef, A.G. [Gaziosmanpasa University, Physics Department, Tasliciftlik Kampasu, Tokat (Turkey); Parlak, M. [Middle East Technical University, Physics Department, Ankara (Turkey); Toppare, L. [Middle East Technical University, Chemistry Department, Ankara (Turkey)

    2005-05-15

    Electronic properties of junctions fabricated by polyamide-polypyrrole composite films polymerized with adjusted doping concentration and various metal contacts (In, Al, Au and Ag) were investigated. For the junctions giving good rectification I{sub 0}, n and {phi}{sub b} were specified. Conductivity of polyamide-polypyrrole composite polymer was obtained as a function of temperature in the 70-320 K range and was found to obey the VRH model. In addition the Mott parameters were evaluated.

  13. Preparation and properties of highly conductive palmitic acid/graphene oxide composites as thermal energy storage materials

    International Nuclear Information System (INIS)

    Mehrali, Mohammad; Latibari, Sara Tahan; Mehrali, Mehdi; Indra Mahlia, Teuku Meurah; Cornelis Metselaar, Hendrik Simon

    2013-01-01

    PA/GO (palmitic acid/graphene oxide) as PCMs (phase change materials) prepared by vacuum impregnation method, have high thermal conductivity. The GO (graphene oxide) composite was used as supporting material to improve thermal conductivity and shape stabilization of composite PCM (phase change material). SEM (Scanning electronic microscope), FT-IR (Fourier transformation infrared spectroscope) and XRD (X-ray diffractometer) were applied to determine microstructure, chemical structure and crystalloid phase of palmitic acid/GO composites, respectively. DSC (Differential scanning calorimeter) test was done to investigate thermal properties which include melting and solidifying temperatures and latent heat. FT-IR analysis represented that the composite instruction of porous palmitic acid and GO were physical. The temperatures of melting, freezing and latent heats of the composite measured through DSC analysis were 60.45, 60.05 °C, 101.23 and 101.49 kJ/kg, respectively. Thermal cycling test showed that the form-stable composite PCM has good thermal reliability and chemical stability. Thermal conductivity of the composite PCM was improved by more than three times from 0.21 to 1.02. As a result, due to their acceptable thermal properties, good thermal reliability, chemical stability and great thermal conductivities, we can consider the prepared form-stable composites as highly conductive PCMs for thermal energy storage applications. - Highlights: • Novel composite PCM with high thermal conductivity and latent heat storage. • New thermal cycling test for thermal reliability of composite PCMs. • Increasing thermal conductivity of composite PCM with graphene oxide. • Increasing thermal stability of phase change material by adding graphene oxide

  14. Investigation of the lithium ion mobility in cyclic model compounds and their ion conduction properties

    Energy Technology Data Exchange (ETDEWEB)

    Thielen, Joerg

    2011-07-27

    In view of both, energy density and energy drain, rechargeable lithium ion batteries outperform other present accumulator systems. However, despite great efforts over the last decades, the ideal electrolyte in terms of key characteristics such as capacity, cycle life, and most important reliable safety, has not yet been identified. Steps ahead in lithium ion battery technology require a fundamental understanding of lithium ion transport, salt association, and ion solvation within the electrolyte. Indeed, well defined model compounds allow for systematic studies of molecular ion transport. Thus, in the present work, based on the concept of immobilizing ion solvents, three main series with a cyclotriphosphazene (CTP), hexaphenylbenzene (HBP), and tetramethylcyclotetrasiloxane (TMS) scaffold were prepared. Lithium ion solvents, among others ethylene carbonate (EC), which has proven to fulfill together with propylene carbonate safety and market concerns in commercial lithium ion batteries, were attached to the different cores via alkyl spacers of variable length. All model compounds were fully characterized, pure and thermally stable up to at least 235 C, covering the requested broad range of glass transition temperatures from -78.1 C up to +6.2 C. While the CTP models tend to rearrange at elevated temperatures over time, which questions the general stability of alkoxide related (poly)phosphazenes, both, the HPB and CTP based models show no evidence of core stacking. In particular the CTP derivatives represent good solvents for various lithium salts, exhibiting no significant differences in the ionic conductivity {sigma}{sub dc} and thus indicating comparable salt dissociation and rather independent motion of cations and ions. In general, temperature-dependent bulk ionic conductivities investigated via impedance spectroscopy follow a William-Landel-Ferry (WLF) type behavior. Modifications of the alkyl spacer length were shown to influence ionic conductivities only in

  15. Correlation of electrochemical properties of expanded pyridinium compounds with their single molecule conductance

    Czech Academy of Sciences Publication Activity Database

    Nováková Lachmanová, Štěpánka; Šebera, Jakub; Kolivoška, Viliam; Gasior, Jindřich; Mészáros, G.; Dupeyre, G.; Lainé, P. P.; Hromadová, Magdaléna

    Roč. 301, FEB 2018 ( 2018 ), s. 301-311 ISSN 0013-4686 R&D Projects: GA ČR GA18-04682S; GA ČR GJ16-07460Y; GA MŠk(CZ) 7AMB15FR027 Grant - others:AV ČR(CZ) MTA-16-02 Program:Bilaterální spolupráce Institutional support: RVO:61388955 Keywords : Expanded pyridinium * Electron transfer and electron transport * Single molecule conductance Subject RIV: CG - Electrochemistry OBOR OECD: Physical chemistry Impact factor: 4.798, year: 2016

  16. Thermophysical Properties of Matter - The TPRC Data Series. Volume 2. Thermal Conductivity - Nonmetallic Solids

    Science.gov (United States)

    1971-01-01

    Rept. NYO-6451, 1-16, 1955. [AD 80 699] Ratcliffe, E.H.. Phys. and Chem. of Glasses, 1.(3), 103-4, 1960. Sujak, B. , ACTA Physica Polonica , 20(2...1954. Boundary Resistance 61. Casimir, H. B. G., "Note on the Conduction of Heat in Crystals," Physica , 5(6), 495-500, 1938. 62. Berman, R., Simon...TP! r, f Theory, Estimation, and Measurement 39« Liquids by a Nonstationary Method." Physica , 19(3) 208-16, 1953. 429. Hooper, F. C. and

  17. ac conductivity and dielectric properties of amorphous Se80Te20-xGex chalcogenide glass film compositions

    International Nuclear Information System (INIS)

    Hegab, N.A.; Afifi, M.A.; Atyia, H.E.; Farid, A.S.

    2009-01-01

    Thin films of the prepared Se 80 Te 20-x Ge x (x = 5, 7 and 10 at.%) were prepared by thermal evaporation technique. X-ray diffraction patterns showed that the films were in amorphous state. The ac conductivity and dielectric properties of the investigated film compositions were studied in the frequency range 0.1-100 kHz and in temperature range (303-373 K). The experimental results indicated that the ac conductivity and the dielectric properties depended on the temperature and frequency. The ac conductivity is found to obey the ω s law, in accordance with the hopping model, s is found to be temperature dependent (s 1 and dielectric loss ε 2 were found to decrease with frequency and increase with temperature. The maximum barrier height W m , calculated from dielectric measurements according to Guintini equation, agrees with that proposed by the theory of hopping over potential barrier as suggested by Elliott in case of chalcogenide glasses. The density of localized states was estimated for the studied film compositions. The variation of the studied properties with Ge content was also investigated.

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

    Science.gov (United States)

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

    2008-07-01

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

  19. Conductivity and electrical properties of corn starch–chitosan blend biopolymer electrolyte incorporated with ammonium iodide

    International Nuclear Information System (INIS)

    Yusof, Y M; Shukur, M F; Illias, H A; Kadir, M F Z

    2014-01-01

    This work focuses on the characteristics of polymer blend electrolytes based on corn starch and chitosan doped with ammonium iodide (NH 4 I). The electrolytes were prepared using the solution cast method. A polymer blend comprising 80 wt% starch and 20 wt% chitosan was found to be the most amorphous blend and suitable to serve as the polymer host. Fourier transform infrared spectroscopy analysis proved the interaction between starch, chitosan and NH 4 I. The highest room temperature conductivity of (3.04 ± 0.32) × 10 −4  S cm −1 was obtained when the polymer host was doped with 40 wt% NH 4 I. This result was further proven by field emission scanning electron microscopy study. All electrolytes were found to obey the Arrhenius rule. Dielectric studies confirm that the electrolytes obeyed non-Debye behavior. The temperature dependence of the power law exponent s for the highest conducting sample follows the quantum mechanical tunneling model. (paper)

  20. Nature of Dielectric Properties, Electric Modulus and AC Electrical Conductivity of Nanocrystalline ZnIn2Se4 Thin Films

    Science.gov (United States)

    El-Nahass, M. M.; Attia, A. A.; Ali, H. A. M.; Salem, G. F.; Ismail, M. I.

    2018-02-01

    The structural characteristics of thermally deposited ZnIn2Se4 thin films were indexed utilizing x-ray diffraction as well as scanning electron microscopy techniques. Dielectric properties, electric modulus and AC electrical conductivity of ZnIn2Se4 thin films were examined in the frequency range from 42 Hz to 106 Hz. The capacitance, conductance and impedance were measured at different temperatures. The dielectric constant and dielectric loss decrease with an increase in frequency. The maximum barrier height was determined from the analysis of the dielectric loss depending on the Giuntini model. The real part of the electric modulus revealed a constant maximum value at higher frequencies and the imaginary part of the electric modulus was characterized by the appearance of dielectric relaxation peaks. The AC electrical conductivity obeyed the Jonscher universal power law. Correlated barrier hopping model was the appropriate mechanism for AC conduction in ZnIn2Se4 thin films. Estimation of the density of states at the Fermi level and activation energy, for AC conduction, was carried out based on the temperature dependence of AC electrical conductivity.

  1. Superhydrophobic conductive textiles with antibacterial property by coating fibers with silver nanoparticles

    International Nuclear Information System (INIS)

    Xue Chaohua; Chen Jia; Yin Wei; Jia Shuntian; Ma Jianzhong

    2012-01-01

    Silver nanoparticles (Ag NPs) were produced on cotton fibers by reduction of [Ag(NH 3 ) 2 ] + complex with glucose. Further modification of the fibers coated by Ag NPs with hexadecyltrimethoxysilane led to superhydrophobic cotton textiles. Scanning electron microscopy images of the textiles showed that the treated fibers were covered with uniform Ag NPs, which generate a dual-size roughness on the textiles favouring the formation of superhydrophobic surfaces, and the Ag NPs formed dense coating around the fibers rendering the intrinsic insulating cotton textiles conductive. Antibacterial test showed that the as-fabricated textiles had high antibacterial activity against the gram-negative bacteria, Escherichia coli. These multifunctional textiles might find applications in biomedical electronic devices.

  2. Tubular array, dielectric, conductivity and electrochemical properties of biodegradable gel polymer electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Sudhakar, Y.N. [Department of Chemistry, Manipal Institute of Technology, Manipal, Karnataka (India); Selvakumar, M., E-mail: chemselva78@gmail.com [Department of Chemistry, Manipal Institute of Technology, Manipal, Karnataka (India); Bhat, D. Krishna [Department of Chemistry, National Institute of Technology Karnataka, Surathkal, Mangalore (India)

    2014-02-15

    Highlights: • A new finding of tubular array of 10–20 μm in length and 1–2 μm in thickness of gel polymer electrolyte (GPE) having 2.2 × 10{sup −3} S cm{sup −1} conductivity is reported. • Thermal and electrochemical characterizations of GPEs show good interaction among the polymer, plasticizer and salt. • GPE based supercapacitor demonstrates high capacitance of 186 F g{sup −1}. • Low temperature studies did not influence much on capacitance values obtained from AC impedance studies. • Charge–discharge exhibits high capacity with excellent cyclic stability and energy density. -- Abstract: A supercapacitor based on a biodegradable gel polymer electrolyte (GPE) has been fabricated using guar gum (GG) as the polymer matrix, LiClO{sub 4} as the doping salt and glycerol as the plasticizer. The scanning electron microscopy (SEM) images of the gel polymer showed an unusual tubular array type surface morphology. FTIR, DSC and TGA results of the GPE indicated good interaction between the components used. Highest ionic conductivity and lowest activation energy values were 2.2 × 10{sup −3} S cm{sup −1} and 0.18 eV, respectively. Dielectric studies revealed ionic behavior and good capacitance with varying frequency of the GPE system. The fabricated supercapacitor showed a maximum specific capacitance value of 186 F g{sup −1} using cyclic voltammetry. Variation of temperature from 273 K to 293 K did not significantly influence the capacitance values obtained from AC impedance studies. Galvanostatic charge–discharge study of supercapacitor indicated that the device has good stability, high energy density and power density.

  3. Divalent Cations Regulate the Ion Conductance Properties of Diverse Classes of Aquaporins

    Directory of Open Access Journals (Sweden)

    Mohamad Kourghi

    2017-11-01

    Full Text Available Aquaporins (AQPs are known to facilitate water and solute fluxes across barrier membranes. An increasing number of AQPs are being found to serve as ion channels. Ion and water permeability of selected plant and animal AQPs (plant Arabidopsis thaliana AtPIP2;1, AtPIP2;2, AtPIP2;7, human Homo sapiens HsAQP1, rat Rattus norvegicus RnAQP4, RnAQP5, and fly Drosophila melanogaster DmBIB were expressed in Xenopus oocytes and examined in chelator-buffered salines to evaluate the effects of divalent cations (Ca2+, Mg2+, Ba2+ and Cd2+ on ionic conductances. AtPIP2;1, AtPIP2;2, HsAQP1 and DmBIB expressing oocytes had ionic conductances, and showed differential sensitivity to block by external Ca2+. The order of potency of inhibition by Ca2+ was AtPIP2;2 > AtPIP2;1 > DmBIB > HsAQP1. Blockage of the AQP cation channels by Ba2+ and Cd2+ caused voltage-sensitive outward rectification. The channels with the highest sensitivity to Ca2+ (AtPIP2;1 and AtPIP2;2 showed a distinctive relief of the Ca2+ block by co-application of excess Ba2+, suggesting that divalent ions act at the same site. Recognizing the regulatory role of divalent cations may enable the discovery of other classes of AQP ion channels, and facilitate the development of tools for modulating AQP ion channels. Modulators of AQPs have potential value for diverse applications including improving salinity tolerance in plants, controlling vector-borne diseases, and intervening in serious clinical conditions involving AQPs, such as cancer metastasis, cardiovascular or renal dysfunction.

  4. A SURVEY OF SEMI-SUPERVISED LEARNING

    OpenAIRE

    Amrita Sadarangani *, Dr. Anjali Jivani

    2016-01-01

    Semi Supervised Learning involves using both labeled and unlabeled data to train a classifier or for clustering. Semi supervised learning finds usage in many applications, since labeled data can be hard to find in many cases. Currently, a lot of research is being conducted in this area. This paper discusses the different algorithms of semi supervised learning and then their advantages and limitations are compared. The differences between supervised classification and semi-supervised classific...

  5. Thermo-mechanical properties of mixed ion-electron conducting membrane materials

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Bingxin

    2011-07-01

    The thesis presents thermo-mechanical properties of La{sub 0.58}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} (LSCF) and Ba{sub 0.5}Sr{sub 0.5}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} (BSCF) perovskite materials, which are considered as oxygen transport membranes (OTM) for gas separation units. Ring-on-ring bending test with disk-shaped samples and depth-sensitive micro-indentation have been used as macroscopic and microscopic tests, respectively. In addition, the thermo-mechanical properties of a third OTM candidate material La{sub 2}NiO{sub 4+{delta}} (LNO) were investigated. The results of the thermo-mechanical measurements with the BSCF revealed an anomaly between 200 C and 400 C. In particular, the temperature dependence of Young's modulus shows a minimum at {proportional_to} 200 C. Fracture stress and toughness exhibit a qualitatively similar behavior with a minimum between 200 C and 400 C, before recovering between 500 C and 800 C. X-ray diffraction analyses verified that BSCF remains cubic in the relevant temperature range. Hence the anomalies were assumed to be related to the transition of Co{sup 3+} spin states reported for other Co-containing perovskites. This assumption could be experimentally confirmed by magnetic susceptibility measurements. The fracture surfaces of the specimens are not affected by the mechanical anomalies at intermediate temperatures, since only a transgranular fracture mode has been observed. Complementary to the mechanical characterization of BSCF, also the temperature dependency of fracture stress and elastic behavior of LSCF have been determined. Phase compositions of LSCF have been studied by in-situ high temperature XRD. Changes in phase composition with temperature are observed. At ambient temperature the LSCF perovskite material comprises two phases: rhombohedral and cubic symmetry. The ratio of the two phases depends on both cooling rate and atmosphere. The transition of rhombohedral to cubic occurs between 700 C and

  6. Variable-Frequency Ultrasonic Treatment on Microstructure and Mechanical Properties of ZK60 Alloy during Large Diameter Semi-Continuous Casting

    Directory of Open Access Journals (Sweden)

    Xingrui Chen

    2017-05-01

    Full Text Available Traditional fixed-frequency ultrasonic technology and a variable-frequency ultrasonic technology were applied to refine the as-cast microstructure and improve the mechanical properties of a ZK60 (Mg–Zn–Zr alloy during large diameter semi-continuous casting. The acoustic field propagation was obtained by numerical simulation. The microstructure of the as-cast samples was characterized by optical and scanning electron microscopy. The variable-frequency ultrasonic technology shows its outstanding ability in grain refinement compared with traditional fixed-ultrasonic technology. The variable-frequency acoustic field promoted the formation of small α-Mg globular grains and changed the distribution and morphology of β-phases throughout the castings. Ultimate tensile strength and elongation are increased to 280 MPa and 8.9%, respectively, which are 19.1% and 45.9% higher than the values obtained from billets without ultrasonic treatment and are 11.6% and 18.7% higher than fixed-frequency ultrasound treated billets. Different refinement efficiencies appear in different districts of billets attributed to the sound attenuation in melt. The variable-frequency acoustic field improves the refinement effect by enhancing cavitation-enhanced heterogeneous nucleation and dendrite fragmentation effects.

  7. Effect of the local morphology in the field emission properties of conducting polymer surfaces

    International Nuclear Information System (INIS)

    De Assis, T A; Borondo, F; Benito, R M; Losada, J C; Andrade, R F S; Miranda, J G V; De Souza, Nara C; De Castilho, C M C; De B Mota, F

    2013-01-01

    In this work, we present systematic theoretical evidence of a relationship between the point local roughness exponent (PLRE) (which quantifies the heterogeneity of an irregular surface) and the cold field emission properties (indicated by the local current density and the macroscopic current density) of real polyaniline (PANI) surfaces, considered nowadays as very good candidates in the design of field emission devices. The latter are obtained from atomic force microscopy data. The electric field and potential are calculated in a region bounded by the rough PANI surface and a distant plane, both boundaries held at distinct potential values. We numerically solve Laplace’s equation subject to appropriate Dirichlet’s condition. Our results show that local roughness reveals the presence of specific sharp emitting spots with a smooth geometry, which are the main ones responsible (but not the only) for the emission efficiency of such surfaces for larger deposition times. Moreover, we have found, with a proper choice of a scale interval encompassing the experimentally measurable average grain length, a highly structured dependence of local current density on PLRE, considering different ticks of PANI surfaces. (paper)

  8. Effect of heat treatments on the tensile and electrical properties of high-strength, high-conductivity copper alloys

    International Nuclear Information System (INIS)

    Zinkle, S.J.; Eatherly, W.S.

    1997-01-01

    The unirradiated tensile properties of CuCrZr produced by two different vendors have been measured following different heat treatments. Room temperature electrical resistivity measurements were also performed in order to estimate the thermal conductivity of these specimens. The thermomechanical conditions studied included solution quenched, solution quenched and aged (ITER reference heat treatment), simulated slow HIP thermal cycle (∼1 degrees C/min cooling from solutionizing temperature) and simulated fast HIP thermal cycle (∼100 degrees C/min cooling from solutionizing temperature). Specimens from the last two heat treatments were tested in both the solution-cooled condition and after subsequent precipitate aging at 475 degrees C for 2 h. Both of the simulated HIP thermal cycles caused a pronounced decreases in the strength and electrical conductivity of CuCrZr. The tensile and electrical properties were unchanged by subsequent aging in the slow HIP thermal cycles caused a pronounced decrease in the strength and electrical conductivity of CuCrZr. The tensile and electrical properties were unchanged by subsequent aging in the slow HIP thermal cycle specimens, whereas the strength and conductivity following aging in the fast HIP thermal cycle improved to ∼65% of the solution quenched and aged CuCrZr values. Limited tensile and electrical resistivity measurements were also made on two new heats of Hycon 3HP CuNiBe. High strength but poor uniform and total elongations were observed at 500 degrees C on one of these new heats of CuNiBe, similar to that observed in other heats

  9. Effect of heat treatments on the tensile and electrical properties of high-strength, high-conductivity copper alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zinkle, S.J.; Eatherly, W.S. [Oak Ridge National Lab., TN (United States)

    1997-08-01

    The unirradiated tensile properties of CuCrZr produced by two different vendors have been measured following different heat treatments. Room temperature electrical resistivity measurements were also performed in order to estimate the thermal conductivity of these specimens. The thermomechanical conditions studied included solution quenched, solution quenched and aged (ITER reference heat treatment), simulated slow HIP thermal cycle ({approximately}1{degrees}C/min cooling from solutionizing temperature) and simulated fast HIP thermal cycle ({approximately}100{degrees}C/min cooling from solutionizing temperature). Specimens from the last two heat treatments were tested in both the solution-cooled condition and after subsequent precipitate aging at 475{degrees}C for 2 h. Both of the simulated HIP thermal cycles caused a pronounced decreases in the strength and electrical conductivity of CuCrZr. The tensile and electrical properties were unchanged by subsequent aging in the slow HIP thermal cycles caused a pronounced decrease in the strength and electrical conductivity of CuCrZr. The tensile and electrical properties were unchanged by subsequent aging in the slow HIP thermal cycle specimens, whereas the strength and conductivity following aging in the fast HIP thermal cycle improved to {approximately}65% of the solution quenched and aged CuCrZr values. Limited tensile and electrical resistivity measurements were also made on two new heats of Hycon 3HP CuNiBe. High strength but poor uniform and total elongations were observed at 500{degrees}C on one of these new heats of CuNiBe, similar to that observed in other heats.

  10. Characteristics of dielectric properties and conduction mechanism of TlInS2:Cu single crystals

    Science.gov (United States)

    El-Nahass, M. M.; Ali, H. A. M.; El-Zaidia, E. F. M.

    2013-12-01

    Single crystals of TlInS2:Cu were grown by the modified Bridgman method. The dielectric behavior of TlInS2:Cu was investigated using the impedance spectroscopy technique. The real (ε1), imaginary (ε2) parts of complex dielectric permittivity and ac conductivity were measured in the frequency range (42-2×105) Hz with a variation of temperature in the range from 291 K to 483 K. The impedance data were presented in Nyquist diagrams for different temperatures. The frequency dependence of σtot (ω) follows the Jonscher's universal dynamic law with the relation σtot (ω)=σdc+Aωs, (where s is the frequency exponent). The mechanism of the ac charge transport across the layers of TlInS2:Cu single crystals was referred to the hopping over localized states near the Fermi level. The examined system exhibits temperature dependence of σac (ω), which showed a linear increase with the increase in temperature at different frequencies. Some parameters were calculated as: the density of localized states near the Fermi level, NF, the average time of charge carrier hopping between localized states, τ, and the average hopping distance, R.

  11. Conducting properties of nearly depleted ZnO nanowire UV sensors fabricated by dielectrophoresis

    International Nuclear Information System (INIS)

    García Núñez, C; García Marín, A; Piqueras, J; Pau, J L; Nanterne, P; Kung, P

    2013-01-01

    ZnO nanowires (NWs) with different radii (r NW ) have been aligned between pre-patterned electrodes using dielectrophoresis (DEP) for the fabrication of high gain UV sensors. The DEP conditions (voltage amplitude and frequency) and electrode material, geometry and size were optimized to enhance the efficiency during the DEP process. To understand the alignment mechanism of the ZnO NWs, the dielectrophoretic force (F DEP ) was analyzed as a function of the DEP conditions and NW dimensions. These studies showed that the DEP alignment process tends to trap NWs with a smaller radius. The effects of NW size on device performance were analyzed by means of I–V measurements in darkness and under illumination (200 nm NW decreases due to the reduction of the conduction volume, until saturation is reached for r NW 8 A W −1 (measured at 5 V and λ NW , presenting a clear blue-shift for NWs with a lower radius (r NW 2 reduces the dynamic range of the photoresponse due to a strong increase of the dark current. (paper)

  12. Arsenic compromises conducting airway epithelial barrier properties in primary mouse and immortalized human cell cultures.

    Directory of Open Access Journals (Sweden)

    Cara L Sherwood

    Full Text Available Arsenic is a lung toxicant that can lead to respiratory illness through inhalation and ingestion, although the most common exposure is through contaminated drinking water. Lung effects reported from arsenic exposure include lung cancer and obstructive lung disease, as well as reductions in lung function and immune response. As part of their role in innate immune function, airway epithelial cells provide a barrier that protects underlying tissue from inhaled particulates, pathogens, and toxicants frequently found in inspired air. We evaluated the effects of a five-day exposure to environmentally relevant levels of arsenic {<4μM [~300 μg/L (ppb] as NaAsO2} on airway epithelial barrier function and structure. In a primary mouse tracheal epithelial (MTE cell model we found that both micromolar (3.9 μM and submicromolar (0.8 μM arsenic concentrations reduced transepithelial resistance, a measure of barrier function. Immunofluorescent staining of arsenic-treated MTE cells showed altered patterns of localization of the transmembrane tight junction proteins claudin (Cl Cl-1, Cl-4, Cl-7 and occludin at cell-cell contacts when compared with untreated controls. To better quantify arsenic-induced changes in tight junction transmembrane proteins we conducted arsenic exposure experiments with an immortalized human bronchial epithelial cell line (16HBE14o-. We found that arsenic exposure significantly increased the protein expression of Cl-4 and occludin as well as the mRNA levels of Cl-4 and Cl-7 in these cells. Additionally, arsenic exposure resulted in altered phosphorylation of occludin. In summary, exposure to environmentally relevant levels of arsenic can alter both the function and structure of airway epithelial barrier constituents. These changes likely contribute to the observed arsenic-induced loss in basic innate immune defense and increased infection in the airway.

  13. Thermal cure effects on electromechanical properties of conductive wires by direct ink write for 4D printing and soft machines

    Science.gov (United States)

    Mu, Quanyi; Dunn, Conner K.; Wang, Lei; Dunn, Martin L.; Qi, H. Jerry; Wang, Tiejun

    2017-04-01

    Recent developments in soft materials and 3D printing are promoting the rapid development of novel technologies and concepts, such as 4D printing and soft machines, that in turn require new methods for fabricating conductive materials. Despite the ubiquity of silver nanoparticles (NPs) in the conducting electrodes of printed electronic devices, their potential use in stretchable conductors has not been fully explored in 4D printing and soft machines. This paper studies the effect of thermal cure conditions on conductivity and electro-mechanical behaviors of silver ink by the direct ink write (DIW) printing approach. We found that the electro-mechanical properties of silver wires can be tailored by controlling cure time and cure temperature to achieve conductivity as well as stretchability. For the silver NP ink we used in the experiments, silver wires cured at 80 °C for 10-30 min have conductivity >1% bulk silver, Young’s modulus printed silver ink patterns on the surface of 3D printed polymer parts, with the future goal of constructing fully 3D printed arbitrarily formed soft and stretchable devices and of applying them to 4D printing. We demonstrated a fully printed functional soft-matter sensor and a circuit element that can be stretched by as much as 45%.

  14. Electrical Conduction Mechanism and Dielectric Properties of Spherical Shaped Fe₃O₄ Nanoparticles Synthesized by Co-Precipitation Method.

    Science.gov (United States)

    Radoń, Adrian; Łukowiec, Dariusz; Kremzer, Marek; Mikuła, Jarosław; Włodarczyk, Patryk

    2018-05-05

    On the basis of dielectric measurements performed in a wide temperature range (173⁻373 K), a comprehensive analysis of the dielectric and electrical properties of magnetite nanoparticles electrical conduction mechanism of compressed spherical shaped Fe₃O₄ nanoparticles was proposed. The electrical conductivity of Fe₃O₄ nanoparticles was related to two different mechanisms (correlated barrier hopping and non-overlapping small polaron tunneling mechanisms); the transition between them was smooth. Additionally, role of grains and grain boundaries with charge carrier mobility and with observed hopping mechanism was described in detail. It has been confirmed that conductivity dispersion (as a function of frequencies) is closely related to both the long-range mobility (conduction mechanism associated with grain boundaries) and to the short-range mobility (conduction mechanism associated with grains). Calculated electron mobility increases with temperature, which is related to the decreasing value of hopping energy for the tunneling of small polarons. The opposite scenario was observed for the value of electron hopping energy.

  15. Density, electrical conductivity, viscosity and excess properties of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide + propylene carbonate binary mixtures

    International Nuclear Information System (INIS)

    Vraneš, Milan; Zec, Nebojša; Tot, Aleksandar; Papović, Snežana; Dožić, Sanja; Gadžurić, Slobodan

    2014-01-01

    Highlights: • Densities of [bmim][NTf 2 ] mixtures with propylene carbonate were measured. • Excess properties were calculated. • Formation of hydrogen bonds between IL and PC was discussed. • Electrical conductivity and viscosity were also measured. • Influence of temperature and composition on mixture properties were studied. -- Abstract: Densities of binary liquid mixtures of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [bmim][NTf 2 ], with propylene carbonate (PC) were measured at temperatures from (293.15 to 323.15) K and at atmospheric pressure over the whole composition range. The electrical conductivity was measured in the range from (293.15 to 328.15) K. Also, viscosity of [bmim][NTf 2 ] + PC binary mixtures was measured from (298.15 to 333.15) K. Excess molar volumes, V E , have been obtained from the experimental densities and were fitted to Redlich–Kister polynomial equation. Other volumetric properties, such as isobaric thermal expansion coefficients, partial molar volumes, apparent molar volumes and partial molar volumes at infinite dilution have been also calculated, in order to obtain information about interactions between PC and selected ionic liquid. Results are discussed in order to understand the hydrogen bonds formation between components of the mixture

  16. On the optical properties of carbon nanotubes. Part I. A general formula for the dynamical optical conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, Morten Grud, E-mail: morteng@math.aau.dk [Department of Mathematical Sciences, Aalborg University, Fredrik Bajers Vej 7G, 9220 Aalborg (Denmark); Ricaud, Benjamin, E-mail: benjamin.ricaud@epfl.ch [Laboratoire de Traitement des Signaux 2, École Polytechnique Fédérale de Lausanne, Lausanne, Vaud (Switzerland); Savoie, Baptiste, E-mail: baptiste.savoie@gmail.com [Dublin Institute for Advanced Studies, School of Theoretical Physics, 10 Burlington Road, Dublin 04 (Ireland)

    2016-02-15

    This paper is the first one in a series of two articles in which we revisit the optical properties of single-walled carbon nanotubes (SWNTs). Produced by rolling up a graphene sheet, SWNTs owe their intriguing properties to their cylindrical quasi-one-dimensional (quasi-1D) structure (the ratio length/radius is experimentally of order of 10{sup 3}). We model SWNT by circular cylinders of small diameters on the surface of which the conduction electron gas is confined by the electric field generated by the fixed carbon ions. The pair-interaction potential considered is the 3D Coulomb potential restricted to the cylinder. To reflect the quasi-1D structure, we introduce a 1D effective many-body Hamiltonian which is the starting-point of our analysis. To investigate the optical properties, we consider a perturbation by a uniform time-dependent electric field modeling an incident light beam along the longitudinal direction. By using Kubo’s method, we derive within the linear response theory an asymptotic expansion in the low-temperature regime for the dynamical optical conductivity at fixed density of particles. The leading term only involves the eigenvalues and associated eigenfunctions of the (unperturbed) 1D effective many-body Hamiltonian and allows us to account for the sharp peaks observed in the optical absorption spectrum of SWNT.

  17. Atributos químicos de solos sob diferentes usos em perímetro irrigado no semiárido de Pernambuco Soil chemical properties under different uses in an irrigated area in the semi arid region of Pernambuco, Brazil

    Directory of Open Access Journals (Sweden)

    Rossini Mattos Corrêa

    2009-04-01

    salinização do solo, tornando suas utilizações agrícolas menos sustentáveis.Soils developed at semi-arid climate can present salt accumulation, which compromise the agricultural use, being increased by inadequate irrigation management. Based on the use, the degradation of these soils can occur at higher or smaller intensity. This study aimed to evaluate the effect of soil uses based on physical and chemical properties of an irrigated area in the semi-arid region of northeastern Brazil. The soil uses were annual crops (C, fruticulture (F, pasture (P, discarded lands (D, or native vegetation (V. Disturbed soil samples were collected from the 0-10, 10-30 and 30-60 cm layers for chemical analysis, and undisturbed samples from the first two layers for soil density analysis. The indicators pH and electrical conductivity of the saturation extract, soil pH, available phosphorus, total organic carbon, exchangeable cations, calcium, magnesium, potassium, and sodium, cation exchange capacity, sum of bases, base saturation percentage, percentage of exchangeable sodium, and carbon stocks were subjected to multivariate analysis by Principal Component Analysis, and clustering by the Tocher method. The soil chemical properties under production systems was different from V; the chemical quality of the production systems C and D, and that of C and P was similar. For the uses C, D, P, and F, the values of the soil properties (pH, pH and electrical conductivity of the saturation extract, exchangeable calcium and magnesium, sum of bases, base saturation and available phosphorus was higher than for V in the three analyzed layers. The highest total organic carbon content was observed under F and P. The electrical conductivity of the saturation extract was higher under C, D and P than under F and V, indicating the beginning of a soil salinization process, thus characterizing them as less sustainable land uses.

  18. Ion-conductive properties of polyether-based composite electrolytes filled with mesoporous silica, alumina and titania

    International Nuclear Information System (INIS)

    Tominaga, Yoichi; Endo, Masanori

    2013-01-01

    Composite polymer electrolytes were prepared consisting of amorphous polyether, Li salt and mesoporous inorganic filler, and we investigated their ion-conductive properties. We synthesized three types of filler, mesoporous silica, alumina and titania (MP-Si, Al, Ti), and characterized their structural and physicochemical properties using SEM, TEM, SAXS and BET surface area measurements. From these measurements, we confirmed that MP fillers have well-defined arrays of mesoporous and hexagonal structures. Dependence on the MP filler content of the glass transition temperature (T g ) revealed that the addition of filler to original polyether-salt electrolyte causes T g decrease, to due to the dissociation of aggregated ions such as triples or crystalline complex domains. The MP-Ti composites had the greatest ionic conductivity (1.4 × 10 −5 S/cm, 7.5 wt% at 30 °C) of all samples, and the values were more than double that of the original. The addition of MP-Ti also increased the lithium transference number, because the electrolyte/filler interface provided active sites that increase mobile Li ions and conducting paths so as to enhance the mobility

  19. Enhanced AC conductivity and dielectric relaxation properties of polypyrrole nanoparticles irradiated with Ni{sup 12+} swift heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Hazarika, J.; Kumar, A., E-mail: ask@tezu.ernet.in

    2014-08-15

    In this paper, we report the 160 MeV Ni{sup 12+} swift heavy ions (SHIs) irradiation effects on AC conductivity and dielectric relaxation properties of polypyrrole (PPy) nanoparticles in the frequency range of 42 Hz–5 MHz. Four ion fluences of 5 × 10{sup 10}, 1 × 10{sup 11}, 5 × 10{sup 11} and 1 × 10{sup 12} ions/cm{sup 2} have been used for the irradiation purpose. Transport properties in the pristine and irradiated PPy nanoparticles have been investigated with permittivity and modulus formalisms to study the polarization effects and conductivity relaxation. With increasing ion fluence, the relaxation peak in imaginary modulus (M{sup ″}) plots shifts toward high frequency suggesting long range motion of the charge carriers. The AC conductivity studies suggest correlated barrier hopping as the dominant transport mechanism. The hopping distance (R{sub ω}) of the charge carriers decreases with increasing the ion fluence. Binding energy (W{sub m}) calculations depict that polarons are the dominant charge carriers.

  20. Thermal Conductivity and High-Frequency Dielectric Properties of Pressureless Sintered SiC-AlN Multiphase Ceramics

    Directory of Open Access Journals (Sweden)

    Jialin Gu

    2018-06-01

    Full Text Available SiC-AlN multiphase ceramics with 10 wt. %Y2O3-BaO-SiO2 additives were fabricated by pressureless sintering in a nitrogen atmosphere. The effects of SiC contents and sintering temperatures on the sinterability, microstructure, thermal conductivity and high-frequency dielectric properties were characterized. In addition to 6H-SiC and AlN, the samples also contained Y3Al5O12 and Y4Al2O9. SiC-AlN ceramics sintered with 50 wt. % SiC at 2173 K exhibited the best thermal diffusivity and thermal conductivity (26.21 mm2·s−1 and 61.02 W·m−1·K−1, respectively. The dielectric constant and dielectric loss of the sample sintered with 50 wt. % SiC and 2123 K were 33–37 and 0.4–0.5 at 12.4–18 GHz. The dielectric constant and dielectric loss of the samples decreased as the frequency of electromagnetic waves increased from 12.4–18 GHz. The dielectric thermal conductivity properties of the SiC-AlN samples are discussed.

  1. The Effect of Vegetation on Soil Water Infiltration and Retention Capacity by Improving Soil Physiochemical Property in Semi-arid Grassland

    Science.gov (United States)

    A, Y.; Wang, G.

    2017-12-01

    Water shortage is the main limiting factor for semi-arid grassland development. However, the grassland are gradually degraded represented by species conversion, biomass decrease and ecosystem structure simplification under the influence of human activity. Soil water characteristics such as moisture, infiltration and conductivity are critical variables affecting the interactions between soil parameters and vegetation. In this study, Cover, Height, Shannon-Wiener diversity index, Pielou evenness index and Richness index are served as indexes of vegetation productivity and community structure. And saturated hydraulic conductivity (Ks) and soil moisture content are served as indexes of soil water characters. The interaction between vegetation and soil water is investigated through other soil parameters, such as soil organic matter content at different vertical depths and in different degradation area (e.g., initial, transition and degraded plots). The results show that Ks significantly controlled by soil texture other than soil organic matter content. So the influence of vegetation on Ks through increasing soil organic content (SOM) might be slight. However, soil moisture content (SMC) appeared significantly positive relationship with SOM and silt content and negative relationship with sand content at all depth, significantly. This indicated that capacity of soil water storage was influenced both by soil texture and organic matter. In addition, the highest correlation coefficient of SMC was with SOM at the sub-surficial soil layer (20 40 cm). At the depth of 20 40 cm, the soil water content was relatively steady which slightly influenced by precipitation and evaporation. But it significantly influenced by soil organic matter content which related to vegetation. The correlation coefficient between SOM and SMC at topsoil layer (0 20 cm) was lowest (R2=0.36, pwater content not only by soil organic matter content but also the other influential factors, such as the root

  2. Ablation resistance and mechanical/conductive properties of ZrB{sub 2} reinforced carbon based composites

    Energy Technology Data Exchange (ETDEWEB)

    Li, X.T.; Shi, J.L.; Zhang, H.; Zhang, G.B.; Guo, Q.G.; Liu, L. [Chinese Academy of Sciences, Taiyuan (China)

    2007-02-15

    Zirconium diboride reinforced carbon (ZrB{sub 2}/C) particulate composites are prepared from petroleum coke, coal tar pitch, and ZrB{sub 2} powder by hot-pressing. The ablation, mechanical, thermal, and electrical properties of the composites are studied. Results show that the composites have excellent flexural strength and thermal conductivity, with highest values reaching 131 MPa and 161 W/mK for a 10% ZrB{sub 2} addition in raw materials. The electrical resistivity reduces rapidly with increasing amount of ZrB{sub 2}. The values of mass and linear ablation rates are lower in the composites than those measured for pure carbon, decreasing with increasing ZrB{sub 2} content, confirming that these materials are promising for ultrahigh temperature materials. Correlations between properties and microstructure of the composites are also discussed.

  3. Electrical transport properties of spray deposited transparent conducting ortho-Zn2SnO4 thin films

    Science.gov (United States)

    Ramarajan, R.; Thangaraju, K.; Babu, R. Ramesh; Joseph, D. Paul

    2018-04-01

    Ortho Zinc Stannate (Zn2SnO4) exhibits excellent electrical and optical properties to serve as alternate transparent electrode in optoelectronic devices. Here we have optimized ortho-Zn2SnO4 thin film by spray pyrolysis method. Deposition was done onto a pre-heated glass substrate at a temperature of 400 °C. The XRD pattern indicated films to be polycrystalline with cubic structure. The surface of films had globular and twisted metal sheet like morphologies. Films were transparent in the visible region with band gap around 3.6 eV. Transport properties were studied by Hall measurements at 300 K. Activation energies were calculated from Arrhenius's plot from temperature dependent electrical measurements and the conduction mechanism is discussed.

  4. A semi-supervised learning approach to predict synthetic genetic interactions by combining functional and topological properties of functional gene network

    Directory of Open Access Journals (Sweden)

    Han Kyungsook

    2010-06-01

    Full Text Available Abstract Background Genetic interaction profiles are highly informative and helpful for understanding the functional linkages between genes, and therefore have been extensively exploited for annotating gene functions and dissecting specific pathway structures. However, our understanding is rather limited to the relationship between double concurrent perturbation and various higher level phenotypic changes, e.g. those in cells, tissues or organs. Modifier screens, such as synthetic genetic arrays (SGA can help us to understand the phenotype caused by combined gene mutations. Unfortunately, exhaustive tests on all possible combined mutations in any genome are vulnerable to combinatorial explosion and are infeasible either technically or financially. Therefore, an accurate computational approach to predict genetic interaction is highly desirable, and such methods have the potential of alleviating the bottleneck on experiment design. Results In this work, we introduce a computational systems biology approach for the accurate prediction of pairwise synthetic genetic interactions (SGI. First, a high-coverage and high-precision functional gene network (FGN is constructed by integrating protein-protein interaction (PPI, protein complex and gene expression data; then, a graph-based semi-supervised learning (SSL classifier is utilized to identify SGI, where the topological properties of protein pairs in weighted FGN is used as input features of the classifier. We compare the proposed SSL method with the state-of-the-art supervised classifier, the support vector machines (SVM, on a benchmark dataset in S. cerevisiae to validate our method's ability to distinguish synthetic genetic interactions from non-interaction gene pairs. Experimental results show that the proposed method can accurately predict genetic interactions in S. cerevisiae (with a sensitivity of 92% and specificity of 91%. Noticeably, the SSL method is more efficient than SVM, especially for

  5. Modification of Aspergillus niger by conducting polymer, Polypyrrole, and the evaluation of electrochemical properties of modified cells.

    Science.gov (United States)

    Apetrei, Roxana-Mihaela; Carac, Geta; Bahrim, Gabriela; Ramanaviciene, Almira; Ramanavicius, Arunas

    2018-06-01

    The enhancement of bioelectrochemical properties of microorganism by in situ formation of conducting polymer within the cell structures (e.g. cell wall) was performed. The synthesis of polypyrrole (Ppy) within fungi (Aspergillus niger) cells was achieved. Two different Aspergillus niger strains were selected due to their ability to produce glucose oxidase, which initiated the Ppy formation through products of enzymatic reaction. The evolution of Ppy structural features was investigated by absorption spectroscopy, cyclic voltammetry and Fourier transform infrared spectroscopy. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. Transport, Optical, and Magnetic Properties of the Conducting Halide Perovskite CH 3NH 3SnI 3

    Science.gov (United States)

    Mitzi, D. B.; Feild, C. A.; Schlesinger, Z.; Laibowitz, R. B.

    1995-01-01

    A low-temperature ( T ≤ 100°C) solution technique is described for the preparation of polycrystalline and single crystal samples of the conducting halide perovskite, CH 3NH 3SnI 3. Transport, Hall effect, magnetic, and optical properties are examined over the temperature range 1.8-300 K, confirming that this unusual conducting halide perovskite is a low carrier density p-type metal with a Hall hole density, 1/ RHe ≃ 2 × 10 19 cm -3. The resistivity of pressed pellet samples decreases with decreasing temperature with resistivity ratio ρ(300 K)/ρ(2 K) ≃ 3 and room temperature resistivity ρ(300 K) ≃ 7 mΩ-cm. A free-carrier infrared reflectivity spectrum with a plasma edge observed at approximately 1600 cm -1 further attests to the metallic nature of this compound and suggests a small optical effective mass, m* ≃ 0.2.

  7. Vibration electrospinning of Polyamide-66/Multiwall Carbon Nanotube Nanocomposite: introducing electrically conductive, ultraviolet blocking and antibacterial properties

    Directory of Open Access Journals (Sweden)

    Zohoori Salar

    2017-09-01

    Full Text Available Fabrication of electro-conductive fiber is a novel process. Nanocomposites of multiwall carbon nanotube/polyamide66 were produced by electrospinning with different amounts of multiwall carbon nanotube. Field emission scanning electron microscope and Fourier transform infrared spectroscopy of samples proved the existence of multiwall carbon nanotube distribution in polyamide 66 nanofibers. Results showed that electro conductivity of electrospun multiwall carbon nanotube/polyamide 66 nano fiber has increased in comparison with electrospun polyamide 66. Moreover, UV blocking of samples was investigated which has shown that using multiwall carbon nanotube in polyamide 66 increases UV blocking of fibers. Furthermore, anti-bacterial activity of nanocomposite showed that these nanocomposites have antibacterial property against both Staphylococcus Aureus and Escherichia Coli bacteria according to AATCC test method.

  8. Length-controlled few-walled carbon nanotubes and their effect on the electrical property of flexible transparent conductive films

    Science.gov (United States)

    Lee, Byeong-Joo; Shin, Eui-Chul; Jeong, Goo-Hwan

    2012-06-01

    We investigated the effect of the length of carbon nanotubes (CNTs) on the electrical property of CNT-based flexible, transparent, and conductive films (TCFs). We grew vertically aligned CNTs with controlled lengths, dispersed them in ethanol by ultrasonication, and spray coated them onto polyethylene terephthalate (PET) sheets. We focused on the variation in the sheet resistance and transmittance of the above-mentioned films as a function of the CNT length, and we found that the optimum CNT length was 200 μm. We concluded that the CNT length should be carefully optimized because a shorter tube affords the advantage of efficient dispersion, while a longer tube helps in reducing the number of contact points between tubes along the electrical conduction path.

  9. Transparent conducting properties of anatase Ti0.94Nb0.06O2 polycrystalline films on glass substrate

    International Nuclear Information System (INIS)

    Hitosugi, T.; Ueda, A.; Nakao, S.; Yamada, N.; Furubayashi, Y.; Hirose, Y.; Konuma, S.; Shimada, T.; Hasegawa, T.

    2008-01-01

    We report on transparent conducting properties of anatase Ti 0.94 Nb 0.06 O 2 (TNO) polycrystalline films on glass substrate, and discuss the role of grain crystallinity and grain boundary on resistivity. Thin films of TNO were deposited using pulsed laser deposition at substrate temperature ranging from room temperature to 350 deg. C, with subsequent H 2 -annealing at 500 deg. C. Polycrystalline TNO films showed resistivity of 4.5 x 10 -4 Ω cm and 1.5 x 10 -3 Ω cm for films prepared at substrate temperature of room temperature and 250 deg. C, respectively. X-ray diffraction measurements and transmission electron microscopy reveal that grain crystallinity and grain boundary play key roles in conductive films

  10. Effect of substrate temperature on ac conduction properties of amorphous and polycrystalline GaSe thin films

    International Nuclear Information System (INIS)

    Thamilselvan, M.; PremNazeer, K.; Mangalaraj, D.; Narayandass, Sa.K.; Yi, Junsin

    2004-01-01

    X-ray diffraction analysis of GaSe thin films used in the present investigation showed that the as-deposited and the one deposited at higher substrate temperature are in amorphous and polycrystalline state, respectively. The alternating current (ac) conduction properties of thermally evaporated films of GaSe were studied ex situ employing symmetric aluminium ohmic electrodes in the frequency range of 120-10 5 Hz at various temperature regimes. For the film deposited at elevated substrate temperature (573 K) the ac conductivity was found to increase with improvement of its crystalline structure. The ac conductivity (σ ac ) is found to be proportional to (ω s ) where s m calculated from ac conductivity measurements are compared with optical studies of our previous reported work for a-GaSe and poly-GaSe thin films. The distance between the localized centres (R), activation energy (ΔE σ ) and the number of sites per unit energy per unit volume N(E F ) at the Fermi level were evaluated for both a-GaSe and poly-GaSe thin films. Goswami and Goswami model has been invoked to explain the dependence of capacitance on frequency and temperature

  11. Electrical conductivity, optical properties and mechanical stability of 3, 4, 9, 10-perylenetetracarboxylic dianhidride based organic semiconductor

    Science.gov (United States)

    Pandey, Mayank; Joshi, Girish M.; Deshmukh, Kalim; Nath Ghosh, Narendra; Nambi Raj, N. Arunai

    2015-05-01

    The 3, 4, 9, 10-perylenetetracarboxylic dianhydride (PTCDA) doped polymer films were prepared with Polypyrrole (PPy) and Polyvinyl alcohol (PVA) polymers by solution-casting. The change in structure and chemical composition of samples was identified by XRD and FTIR respectively. The UV-visible spectroscopy demonstrates the optical characteristics and band gap properties of sample. The homogeneous morphology of sample for higher wt% of PTCDA was examined by atomic force microscopy (AFM). The differential scanning calorimetry (DSC) results demonstrate the decrease in melting temperature (Tm) and degree of crystallinity (χc%) of polymeric organic semiconductor. The mechanical property demonstrates the high tensile strength and improved plasticity nature. Impedance spectroscopy was evaluated to determine the conductivity response of polymeric organic semiconductor. The highest DC conductivity (2.08×10-3 S/m) was obtained for 10 wt% of PTCDA at 140 °C. The decrease in activation energy (Ea) represents the non-Debye process and was evaluated from the slope of ln σdc vs. 103/T plot.

  12. A Three-Dimensional Porous Conducting Polymer Composite with Ultralow Density and Highly Sensitive Pressure Sensing Properties

    Directory of Open Access Journals (Sweden)

    Jin-Dong Su

    2016-01-01

    Full Text Available An ultralight conducting polyaniline/SiC/polyacrylonitrile (PANI/SiC/PAN composite was fabricated by in situ polymerization of aniline monomer on the surface of fibers in SiC/PAN aerogel. The SiC/PAN aerogel was obtained by electrospinning, freeze-drying, and heat treatment. The ingredient, morphology, structure, and electrical properties of the aerogel before and after in situ polymerization were investigated by X-ray powder diffraction (XRD, Fourier transform infrared spectroscopy (FT-IR, scanning electron microscope (SEM, and voltage-current characteristic measurement. The thermostability of PANI/SiC/PAN composite was investigated by thermogravimetric analysis (TGA and electrical resistance measured at different temperatures. The density of the PANI/SiC/PAN composite was approximately 0.211 g cm−3, the porosity was 76.44%, and the conductivity was 0.013 S m−1. The pressure sensing properties were evaluated at room temperature. The electrical resistance of as-prepared sample decreased gradually with the increase of pressure. Furthermore, the pressure sensing process was reversible and the response time was short (about 1 s. This composite may have application in pressure sensor field.

  13. A Three-Dimensional Porous Conducting Polymer Composite with Ultralow Density and Highly Sensitive Pressure Sensing Properties

    International Nuclear Information System (INIS)

    Su, J. D.; Sun, J.L.; Chen, J.H.; Jia, X.Sh.; Li, J.T.; Yan, X.; Long, Y.Z.; Lou, T.; Yan, X.; Long, Y.Z.

    2016-01-01

    An ultra light conducting poly aniline/Si C/polyacrylonitrile (PANI/Si C/PAN) composite was fabricated by in situ polymerization of aniline monomer on the surface of fibers in Si C/PAN aerogel. The Si C/PAN aerogel was obtained by electro spinning, freeze-drying, and heat treatment. The ingredient, morphology, structure, and electrical properties of the aerogel before and after in situ polymerization were investigated by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and voltage-current characteristic measurement. The thermostability of PANI/Si C/PAN composite was investigated by thermogravimetric analysis (TGA) and electrical resistance measured at different temperatures. The density of the PANI/SiC/PAN composite was approximately 0.211gcm - 3, the porosity was 76.44%, and the conductivity was 0.013Sm - 1. The pressure sensing properties were evaluated at room temperature. The electrical resistance of as-prepared sample decreased gradually with the increase of pressure. Furthermore, the pressure sensing process was reversible and the response time was short (about 1s). This composite may have application in pressure sensor field

  14. Structures and electrochemical properties of pyrolytic carbon films infiltrated from gas phase into electro-conductive substrates derived from wood

    International Nuclear Information System (INIS)

    Ohzawa, Yoshimi; Mitani, Masami; Li, Jianling; Nakajima, Tsuyoshi

    2004-01-01

    Using the pressure-pulsed chemical vapor infiltration technique, pyrolytic carbon (pyrocarbon) films were deposited into two sorts of conductive porous substrates, that is, the carbonized wood (A) and the TiN-coated wood (B). Structures and electrochemical properties were investigated as the negative electrodes of lithium-ion secondary battery. The electrodes had the three-dimensionally continuous current paths in the pyrocarbon-based anodes without the organic binders and the additional conductive fillers. The pyrocarbon films adhered tightly to the carbonized wood or TiN as current collector. These macro-structures of electrodes were effective in improving the high rate property. The sort of substrates affected the nano-structure of pyrocarbon. The pyrocarbon in sample (A) had the relatively high crystallinity, whereas the pyrocarbon in sample (B) was disordered. The capacity of pyrocarbon in sample (B) was higher than that of sample (A), reflecting the disordered microstructure of pyrocarbon film (B). However, sample (A) showed higher Coulombic efficiency at first cycle (i.e. 87%) than that of sample (B), which would result from the high crystallinity, laminar microstructure and low surface area of pyrocarbon in sample (A)

  15. Artificial nacre-like papers based on noncovalent functionalized boron nitride nanosheets with excellent mechanical and thermally conductive properties

    Science.gov (United States)

    Zeng, Xiaoliang; Ye, Lei; Yu, Shuhui; Li, Hao; Sun, Rong; Xu, Jianbin; Wong, Ching-Ping

    2015-04-01

    Inspired by the nano/microscale hierarchical structure and the precise inorganic/organic interface of natural nacre, we fabricated artificial nacre-like papers based on noncovalent functionalized boron nitride nanosheets (NF-BNNSs) and poly(vinyl alcohol) (PVA) via a vacuum-assisted self-assembly technique. The artificial nacre-like papers exhibit excellent tensile strength (125.2 MPa), on a par with that of the natural nacre, and moreover display a 30% higher toughness (2.37 MJ m-3) than that of the natural nacre. These excellent mechanical properties result from an ordered `brick-and-mortar' arrangement of NF-BNNSs and PVA, in which the long-chain PVA molecules act as the bridge to link NF-BNNSs via hydrogen bonds. The resulting papers also render high thermal conductivity (6.9 W m-1 K-1), and reveal their superiority as flexible substrates to support light-emitting-diode chips. The combined mechanical and thermal properties make the materials highly desirable as flexible substrates for next-generation commercial portable electronics.Inspired by the nano/microscale hierarchical structure and the precise inorganic/organic interface of natural nacre, we fabricated artificial nacre-like papers based on noncovalent functionalized boron nitride nanosheets (NF-BNNSs) and poly(vinyl alcohol) (PVA) via a vacuum-assisted self-assembly technique. The artificial nacre-like papers exhibit excellent tensile strength (125.2 MPa), on a par with that of the natural nacre, and moreover display a 30% higher toughness (2.37 MJ m-3) than that of the natural nacre. These excellent mechanical properties result from an ordered `brick-and-mortar' arrangement of NF-BNNSs and PVA, in which the long-chain PVA molecules act as the bridge to link NF-BNNSs via hydrogen bonds. The resulting papers also render high thermal conductivity (6.9 W m-1 K-1), and reveal their superiority as flexible substrates to support light-emitting-diode chips. The combined mechanical and thermal properties make

  16. Is optimality in stomatal conductance an endogenous process or an emergent property arising from interactions with the environment?

    Science.gov (United States)

    Resco de Dios, Victor; Gessler, Arthur; Ferrio, Juan Pedro; Bahn, Michael; Milcu, Alexandru; Tissue, David; Voltas, Jordi; Roy, Jacques

    2016-04-01

    Plants are sessile and poikilothermic organisms that need to respond and adjust promptly to an ever-changing environment. Over a single 24 h period, a plant may experience the same level of variation in radiation as in its entire life-time and, in some climates, the oscillation in day-night temperature and vapor pressure deficit might be of similar magnitude to that experienced across a full year. Plants need to maintain a positive C balance without depleting soil water reserves in the face of such a diverse environment, and feedbacks between assimilation (A) and water losses (E) are thought to have evolved to optimize stomatal conductance (gs). In short, the optimal conductance hypothesis proposes that cross-talks between A and stomatal conductance gs lead to a constant marginal water use (λ) during a day, such that A is maximized and E minimized. The biological mechanism by which biochemical processes would feedback gs remains unknown, but multiple studies have shown empirical support for this hypothesis, leading to its current consideration of theory by many. Here we test whether optimal stomatal conductance is an endogenous property, that is, driven solely by factors internal to the plant, and in the absence of environmental fluctuations. After 5 days of entrainment, where monoculture canopies of bean and of cotton were subjected to the average environmental conditions of an August sunny day in Montpellier (at the CNRS European Ecotron, FR), we kept temperature, relative humidity and photosynthetically active radiation constant for 48 h at the values observed at noon. During this period, we monitored leaf gas exchange continuously every two minutes, and canopy gas exchange every 15 minutes. We observed a periodic oscillation in λ, showing a 24 h period, and consistent with a circadian regulation of water use efficiency. Hourly variations in λ could thus not be explained by the optimal stomatal hypothesis. Moreover, the pattern of variation (of maximal water

  17. Effect of cross-linkable polymer on the morphology and properties of transparent multi-walled carbon nanotube conductive films

    International Nuclear Information System (INIS)

    Huang, Yuan-Li; Tien, Hsi-Wen; Ma, Chen-Chi M.; Teng, Chih-Chun; Yu, Yi-Hsiuan; Yang, Shin-Yi; Wei, Ming-Hsiung; Wu, Sheng-Yen

    2011-01-01

    In this study, we fabricated optically transparent and electrically conductive multi-walled carbon nanotube (MWCNT) thin films using a spray-coating technique. The transparency and the electrical resistance of thin film are dependent on the nanotube content deposited on the polyethylene terephthalate (PET) substrate. Poly(acrylic acid) (PAA) and poly(N-vinyl pyrrolidone) (PVP) were used as adhesion promoters to improve MWCNT coating more significantly. The cross-linked polymer resulted in a superior bond between the MWCNTs and the substrates. The surface electrical resistance was significantly lower than the original sheet after nitric acid (HNO 3 ) treatment because of the removed surfactant and the increased interconnecting networks of MWCNT bundles, thus improving the electrical and optical properties of the films. Stronger interaction between the MWCNTs and the substrates resulted in lower decomposition of the polymer chain and less amounts of MWCNTs separated into the HNO 3 solution. The lower sheet electrical resistance of PVP/PAA-g-MWCNT conductive films on the PET substrate was because of a more complete conductive path with the cross-linked polymer than that without. Such an improved sheet of electrical resistance varied from 8.83 x 10 4 Ω/□ to 2.65 x 10 3 Ω/□ with 5.0 wt.% PVP/PAA-g-MWCNT sprayed on the PET after acid treatment.

  18. Effect of cross-linkable polymer on the morphology and properties of transparent multi-walled carbon nanotube conductive films

    Science.gov (United States)

    Huang, Yuan-Li; Tien, Hsi-Wen; Ma, Chen-Chi M.; Teng, Chih-Chun; Yu, Yi-Hsiuan; Yang, Shin-Yi; Wei, Ming-Hsiung; Wu, Sheng-Yen

    2011-10-01

    In this study, we fabricated optically transparent and electrically conductive multi-walled carbon nanotube (MWCNT) thin films using a spray-coating technique. The transparency and the electrical resistance of thin film are dependent on the nanotube content deposited on the polyethylene terephthalate (PET) substrate. Poly(acrylic acid) (PAA) and poly(N-vinyl pyrrolidone) (PVP) were used as adhesion promoters to improve MWCNT coating more significantly. The cross-linked polymer resulted in a superior bond between the MWCNTs and the substrates. The surface electrical resistance was significantly lower than the original sheet after nitric acid (HNO 3) treatment because of the removed surfactant and the increased interconnecting networks of MWCNT bundles, thus improving the electrical and optical properties of the films. Stronger interaction between the MWCNTs and the substrates resulted in lower decomposition of the polymer chain and less amounts of MWCNTs separated into the HNO 3 solution. The lower sheet electrical resistance of PVP/PAA-g-MWCNT conductive films on the PET substrate was because of a more complete conductive path with the cross-linked polymer than that without. Such an improved sheet of electrical resistance varied from 8.83 × 10 4 Ω/□ to 2.65 × 10 3 Ω/□ with 5.0 wt.% PVP/PAA-g-MWCNT sprayed on the PET after acid treatment.

  19. A Ta/W mixed addenda heteropolyacid with excellent acid catalytic activity and proton-conducting property

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shujun; Peng, Qingpo [School of Chemistry and Chemical Engineering, Henan Key Laboratory of Boron Chemistry and Advanced Energy Materials, Henan Normal University, Xinxiang, Henan 453007 (China); Chen, Xuenian, E-mail: xnchen@htu.edu.cn [School of Chemistry and Chemical Engineering, Henan Key Laboratory of Boron Chemistry and Advanced Energy Materials, Henan Normal University, Xinxiang, Henan 453007 (China); Wang, Ruoya; Zhai, Jianxin; Hu, Weihua [School of Chemistry and Chemical Engineering, Henan Key Laboratory of Boron Chemistry and Advanced Energy Materials, Henan Normal University, Xinxiang, Henan 453007 (China); Ma, Fengji, E-mail: fengji.ma@yahoo.com [College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan 453000 (China); Zhang, Jie, E-mail: jie.zhang@htu.edu.cn [School of Chemistry and Chemical Engineering, Henan Key Laboratory of Boron Chemistry and Advanced Energy Materials, Henan Normal University, Xinxiang, Henan 453007 (China); Liu, Shuxia [Key Laboratory of Polyoxometalates Science of Ministry of Education, College of Chemistry, Northeast Normal University, Changchun City, Jilin 130024 (China)

    2016-11-15

    A new HPAs H{sub 20}[P{sub 8}W{sub 60}Ta{sub 12}(H{sub 2}O){sub 4}(OH){sub 8}O{sub 236}]·125H{sub 2}O (H-1) which comprises a Ta/W mixed addenda heteropolyanion, 20 protons, and 125 crystalline water molecules has been prepared through ion-exchange method. The structure and properties of H-1 have been explored in detail. AC impedance measurements indicate that H-1 is a good solid state proton conducting material at room temperature with a conductivity value of 7.2×10{sup −3} S cm{sup −1} (25 °C, 30% RH). Cyclic voltammograms of H-1 indicate the electrocatalytic activity towards the reduction of nitrite. Hammett acidity constant H{sub 0} of H-1 in CH{sub 3}CN is −2.91, which is the strongest among the present known HPAs. Relatively, H-1 exhibits excellent catalytic activities toward acetal reaction. - Highlights: • A Ta/W mixed addenda Heteropolyacid (H-1) was isolated. • Hammett acidity constant H{sub 0} of H-1 is the strongest among the present known HPAs. • H-1 exhibits excellent catalytic activities toward acetal reaction. • H-1 is a good solid state proton conducting material at room temperature.

  20. Mussel-Inspired Anisotropic Nanocellulose and Silver Nanoparticle Composite with Improved Mechanical Properties, Electrical Conductivity and Antibacterial Activity

    Directory of Open Access Journals (Sweden)

    Hoang-Linh Nguyen

    2016-03-01

    Full Text Available Materials for wearable devices, tissue engineering and bio-sensing applications require both antibacterial activity to prevent bacterial infection and biofilm formation, and electrical conductivity to electric signals inside and outside of the human body. Recently, cellulose nanofibers have been utilized for various applications but cellulose itself has neither antibacterial activity nor conductivity. Here, an antibacterial and electrically conductive composite was formed by generating catechol mediated silver nanoparticles (AgNPs on the surface of cellulose nanofibers. The chemically immobilized catechol moiety on the nanofibrous cellulose network reduced Ag+ to form AgNPs on the cellulose nanofiber. The AgNPs cellulose composite showed excellent antibacterial efficacy against both Gram-positive and Gram-negative bacteria. In addition, the catechol conjugation and the addition of AgNP induced anisotropic self-alignment of the cellulose nanofibers which enhances electrical and mechanical properties of the composite. Therefore, the composite containing AgNPs and anisotropic aligned the cellulose nanofiber may be useful for biomedical applications.

  1. Numerical study of different conduction models for Al_2O_3-water nanofluid with variable properties inside a trapezoidal enclosure

    International Nuclear Information System (INIS)

    Arani, Ali Akbar Abbasian; Azemati, Ali Akbar; Rezaee, Mohammad; Hadavand, Behzad Shirkavand

    2017-01-01

    Natural convection in enclosures containing nanofluids is important in physical and environmental applications. Different models for conduction have been developed because of the importance of this phenomenon in natural convection in enclosures. In this study, effects of conduction models of Chon, Corcione, Khanafer, and Koo and Kleinstreuer on the natural convection inside a trapezoidal enclosure with hot and cold walls are evaluated numerically. The enclosure contains Al_2O_3-water nanofluid with variable properties. Effects of the conduction models on fluid flow, natural convection, variations in volume fraction, and diameter of nanoparticles in the models, as well as the variations in the Rayleigh number, are examined. Results show that at Rayleigh numbers of 105 and 106, the maximum and minimum values of the average Nusselt number are obtained using the models of Khanafer and Chon, respectively. In all models, the average Nusselt number presents upward and downward trends when the volume fraction of nanoparticles increases but decreases when the di- ameter of the nanoparticles increases. At Ra = 105 in all models, as the volume fraction of nanoparticles increases, the nanofluid provides a higher average Nusselt number compared with the base fluid. By contrast, at Ra = 106, at volume fractions larger than 0.01 and using the model of Chon, the average Nusselt number of the nanofluid is lower compared with that of the base fluid.

  2. Effects of ageing time on the mechanical and conductivity properties for various round bar diameters of AA 2219 Al alloy

    Directory of Open Access Journals (Sweden)

    T. Ram Prabhu

    2017-02-01

    Full Text Available In the present study, AA 2219 alloys of 120 mm round bar are forged into various round bars (25, 50, 75 mm and subjected to T6 temper heat treatment to identify the peak ageing time for various round bars. The electrical conductivity of the round bars is also measured and correlated with the mechanical properties. It is found that the peak ageing time is 23 h and does not vary up to 75 mm round bar. It increases to 25 h for the 120 mm round bar. The yield and tensile strength of the alloy are found to be in the range of 288–304 MPa and 410–428 MPa for the peak ageing condition. The hardness and conductivity vary in the range of 121–128 BHN and 30–30.96% IACS respectively for the peak ageing condition. Although a near linear relation is found to exist between the strength/hardness and the electrical conductivity values for the selected heat treatment parameters (solution temperature: 535 °C, ageing temperature: 191 °C and the peak ageing time: 23 h, the slope of the curve is different for different round bars. Microstructure characterization studies show the precipitate coarsening with increasing ageing time. Further, precipitate segregation is not found in the microstructure for any cases of round bar diameter and ageing time combinations.

  3. Clay/Polyaniline Hybrid through Diazonium Chemistry: Conductive Nanofiller with Unusual Effects on Interfacial Properties of Epoxy Nanocomposites.

    Science.gov (United States)

    Jlassi, Khouloud; Chandran, Sarath; Poothanari, Mohammed A; Benna-Zayani, Mémia; Thomas, Sabu; Chehimi, Mohamed M

    2016-04-12

    The concept of conductive network structure in thermoset matrix without sacrificing the inherent mechanical properties of thermoset polymer (e.g., epoxy) is investigated here using "hairy" bentonite fillers. The latter were prepared through the in situ polymerization of aniline in the presence of 4-diphenylamine diazonium (DPA)-modified bentonite (B-DPA) resulting in a highly exfoliated bentonite-DPA/polyaniline (B-DPA/PANI). The nanocomposite filler was mixed with diglycidyl ether of bisphenol A (DGEBA), and the curing agent (4,4'-diaminodiphenylsulfone) (DDS) at high temperature in order to obtain nanocomposites through the conventional melt mixing technique. The role of B-DPA in the modification of the interface between epoxy and B-DPA/polyaniline (B-DPA/PANI) is investigated and compared with the filler B/PANI prepared without any diazonium modification of the bentonite. Synergistic improvement in dielectric properties and mechanical properties points to the fact that the DPA aryl groups from the diazonium precursor significantly modify the interface by acting as an efficient stress transfer medium. In DPA-containing nanocomposites, unique fibril formation was observed on the fracture surface. Moreover, dramatic improvement (210-220%) in fracture toughness of epoxy composite was obtained with B-DPA/PANI filler as compared to the weak improvement of 20-30% noted in the case of the B/PANI filler. This work shows that the DPA diazonium salt has an important effect on the improvement of the interfacial properties and adhesion of DGEBA and clay/PANI nanofillers.

  4. Electroactive semi-interpenetrating polymer networks architecture with tunable IR reflectivity

    Science.gov (United States)

    Chevrot, C.; Teyssié, D.; Verge, P.; Goujon, L.; Tran-Van, F.; Vidal, F.; Aubert, P. H.; Peralta, S.; Sauques, L.

    2011-04-01

    A promising alternative of multi-layered devices showing electrochromic properties results from the design of a self-supported semi-interpenetrating polymer network (semi-IPN) including an electronic conductive polymer (ECP) formed within. The formation of the ECP in the network has already been described by oxidative polymerization using iron trichloride as an oxidant and leading to conducting semi-IPN with mixed electronic and ionic conductivities as well as convenient mechanical properties. This presentation relates to the elaboration of such semi-IPN using polyethyleneoxide (PEO) network or a PEO/NBR (Nitrile Butadiene Rubber) IPN in which a linear poly (3,4-ethylenedioxythiophene) (PEDOT) is formed symmetrically and selectively as very thin layers very next to the two main faces of the film matrix. PEO/PEDOT semi-IPNs lead to interesting optical reflective properties in the IR between 0.8 and 25 μm. Reflectance contrasts up to 35 % is observed when, after swelling in an ionic liquid, a low voltage is applied between the two main faces of the film. However the low flexibility and brittleness of the film and a slow degradation in air at temperature up from 60°C prompted to replace the PEO matrix by a flexible PEO/NBR IPN one. Indeed, the combination of NBR and PEO in an IPN leads to materials possessing flexible properties, good ionic conductivity at 25°C as well as a better resistance to thermal ageing. Finally, NBR/PEO/PEDOT semi-IPNs allow observing comparable reflectance contrast in the IR range than those shown by PEO/PEDOT semi-IPNs.

  5. Facile fabrication and characterization of poly(tetrafluoroethylene)@polypyrrole/nano-silver composite membranes with conducting and antibacterial property

    Science.gov (United States)

    Shi, Zhiquan; Zhou, Hui; Qing, Xutang; Dai, Tingyang; Lu, Yun

    2012-06-01

    Porous poly(tetrafluoroethylene) (PTFE) membranes play an important role in air purification and separation engineering. To achieve the bi-functionality of conducting and antibacterial property, two kinds of poly(tetrafluoroethylene)@ polypyrrole/nano-silver composite membranes have been prepared. One involves hydrophobic polypyrrole/nano-silver composite with hollow capsule nanostructures immobilized on the surface of the PTFE membranes. The other is a type of composite membranes with polypyrrole/nano-silver composite wholly packed on the fibrils of the expand PTFE membrane to form core/shell coaxial cable structures. The structure and morphology of the two kinds of composite membranes have been characterized by FTIR, UV-vis, XRD, TGA and SEM measurements. Possible formation mechanisms of the hollow capsules and the core/shell nanocable structures have been discussed in detail. The antibacterial effects of composite membranes are also briefly investigated.

  6. Enhanced catalytic and dopamine sensing properties of electrochemically reduced conducting polymer nanocomposite doped with pure graphene oxide.

    Science.gov (United States)

    Wang, Wenting; Xu, Guiyun; Cui, Xinyan Tracy; Sheng, Ge; Luo, Xiliang

    2014-08-15

    Significantly enhanced catalytic activity of a nanocomposite composed of conducting polymer poly (3,4-ethylenedioxythiophene) (PEDOT) doped with graphene oxide (GO) was achieved through a simple electrochemical reduction process. The nanocomposite (PEDOT/GO) was electrodeposited on an electrode and followed by electrochemical reduction, and the obtained reduced nanocomposite (PEDOT/RGO) modified electrode exhibited lowered electrochemical impedance and excellent electrocatalytic activity towards the oxidation of dopamine. Based on the excellent catalytic property of PEDOT/RGO, an electrochemical sensor capable of sensitive and selective detection of DA was developed. The fabricated sensor can detect DA in a wide linear range from 0.1 to 175μM, with a detection limit of 39nM, and it is free from common interferences such as uric acid and ascorbic acid. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Energy gaps, valence and conduction charge densities and optical properties of GaAs1‑xPx

    Science.gov (United States)

    Al-Hagan, O. A.; Algarni, H.; Bouarissa, N.; Alhuwaymel, T. F.; Ajmal Khan, M.

    2018-04-01

    The electronic structure and its derived valence and conduction charge distributions along with the optical properties of zinc-blende GaAs1‑xPx ternary alloys have been studied. The calculations are performed using a pseudopotential approach under the virtual crystal approximation (VCA) which takes into account the compositional disorder effect. Our findings are found to be generally in good accord with experiment. The composition dependence of direct and indirect bandgaps showed a clear bandgap bowing. The nature of the gap is found to depend on phosphorous content. The bonding and ionicity of the material of interest have been examined in terms of the anti-symmetric gap and charge densities. The variation in the optical constants versus phosphorous concentration has been discussed. The present investigation may give a useful applications in infrared and visible spectrum light emitters.

  8. The properties of transparent conducting molybdenum-doped ZnO films grown by radio frequency magnetron sputtering

    International Nuclear Information System (INIS)

    Xiu Xian-Wu; Zhao Wen-Jing

    2012-01-01

    Transparent conducting molybdenum-doped zinc oxide films are prepared by radio frequency (RF) magnetron sputtering at ambient temperature. The MoO 3 content in the target varies from 0 to 5 wt%, and each film is polycrystalline with a hexagonal structure and a preferred orientation along the c axis. The resistivity first decreases and then increases with the increase in MoO 3 content. The lowest resistivity achieved is 9.2×10 −4 Ω·cm, with a high Hall mobility of 30 cm 2 ·V −1 ·s 1 and a carrier concentration of 2.3×10 20 cm −3 at an MoO 3 content of 2 wt%. The average transmittance in the visible range is reduced from 91% to 80% with the increase in the MoO 3 content in the target. (condensed matter: structural, mechanical, and thermal properties)

  9. Influence of the applied potentials difference on structural and conductive properties of CoZnO nanotubes

    Science.gov (United States)

    Ibragimova, M. A.; Kozlovskiy, A. L.; Kenzhina, I. E.; Zdorovets, M. V.

    2018-04-01

    A series of CoZnO nanotubes was obtained by electrochemical deposition, with different atomic metal coefficients, due to a change in the applied potential difference. A systematic study of the morphology, structural and conductive properties of nanotubes was also carried out. It is established that the samples synthesized at the applied potentials difference of 1.5 and 1.75 V are three-component systems consisting of two oxide phases of ZnO and CoO1.92 cubic system and a phase of a solid solution of substitution Co0.65Zn0.35 of hexagonal type. The samples synthesized at a potential difference of 2.0 V represent an alloy of two oxide phases, ZnO and CoO1.92.

  10. Performance evaluation of cryogenic counter-flow heat exchangers with longitudinal conduction, heat in-leak and property variations

    Science.gov (United States)

    Jiang, Q. F.; Zhuang, M.; Zhu, Z. G.; Y Zhang, Q.; Sheng, L. H.

    2017-12-01

    Counter-flow plate-fin heat exchangers are commonly utilized in cryogenic applications due to their high effectiveness and compact size. For cryogenic heat exchangers in helium liquefaction/refrigeration systems, conventional design theory is no longer applicable and they are usually sensitive to longitudinal heat conduction, heat in-leak from surroundings and variable fluid properties. Governing equations based on distributed parameter method are developed to evaluate performance deterioration caused by these effects. The numerical model could also be applied in many other recuperators with different structures and, hence, available experimental data are used to validate it. For a specific case of the multi-stream heat exchanger in the EAST helium refrigerator, quantitative effects of these heat losses are further discussed, in comparison with design results obtained by the common commercial software. The numerical model could be useful to evaluate and rate the heat exchanger performance under the actual cryogenic environment.

  11. Study on the optical and electrical properties of tetracyanoethylene doped bilayer graphene stack for transparent conducting electrodes

    International Nuclear Information System (INIS)

    Limbu, Tej B.; Barrionuevo, Danilo; Katiyar, Ram S.; Morell, Gerardo; Mendoza, Frank; Carpena, Jennifer; Maruyama, Benji; Weiner, Brad R.

    2016-01-01

    We report the optical and electrical properties of chemically-doped bilayer graphene stack by tetracyanoethylene, a strong electron acceptor. The Tetracyanoethylene doping on the bilayer graphene via charge transfer was confirmed by Raman spectroscopy and Infrared Fourier transform spectroscopy. Doped graphene shows a significant increase in the sheet carrier concentration of up to 1.520 × 10"1"3 cm"−"2 with a concomitant reduction of the sheet resistance down to 414.1 Ω/sq. The high optical transmittance (ca. 84%) in the visible region in combination with the low sheet resistance of the Tetracyanoethylene-doped bilayer graphene stack opens up the possibility of making transparent conducting electrodes for practical applications.

  12. Surface plasmon resonances, optical properties, and electrical conductivity thermal hystersis of silver nanofibers produced by the electrospinning technique.

    Science.gov (United States)

    Barakat, Nasser A M; Woo, Kee-Do; Kanjwal, Muzafar A; Choi, Kyung Eun; Khil, Myung Seob; Kim, Hak Yong

    2008-10-21

    In the present study, silver metal nanofibers have been successfully prepared by using the electrospinning technique. Silver nanofibers have been produced by electrospinning a sol-gel consisting of poly(vinyl alcohol) and silver nitrate. The dried nanofiber mats have been calcined at 850 degrees C in an argon atmosphere. The produced nanofibers do have distinct plasmon resonance compared with the reported silver nanoparticles. Contrary to the introduced shapes of silver nanoparticles, the nanofibers have a blue-shifted plasmon resonance at 330 nm. Moreover, the optical properties study indicated that the synthesized nanofibers have two band gap energies of 0.75 and 2.34 eV. An investigation of the electrical conductivity behavior of the obtained nanofibers shows thermal hystersis. These privileged physical features greatly widen the applications of the prepared nanofibers in various fields.

  13. Heat conduction

    International Nuclear Information System (INIS)

    Grigull, U.; Sandner, H.

    1984-01-01

    Included are discussions of rates of heat transfer by conduction, the effects of varying and changing properties, thermal explosions, distributed heat sources, moving heat sources, and non-steady three-dimensional conduction processes. Throughout, the importance of thinking both numerically and symbolically is stressed, as this is essential to the development of the intuitive understanding of numerical values needed for successful designing. Extensive tables of thermophysical properties, including thermal conductivity and diffusivity, are presented. Also included are exact and approximate solutions to many of the problems that arise in practical situations

  14. Improved optoelectronics properties of ITO-based transparent conductive electrodes with the insertion of Ag/Ni under-layer

    Science.gov (United States)

    Ali, Ahmad Hadi; Abu Bakar, Ahmad Shuhaimi; Hassan, Zainuriah

    2014-10-01

    ITO-based transparent conductive electrodes (TCE) with Ag/Ni thin metal under-layer were deposited on Si and glass substrates by thermal evaporator and RF magnetron sputtering system. Ceramic ITO with purity of 99.99% and In2O3:SnO2 weight ratio of 90:10 was used as a target at room temperature. Post-deposition annealing was performed on the TCE at moderate temperature of 500 °C, 600 °C and 700 °C under N2 ambient. It was observed that the structural properties, optical transmittance, electrical characteristics and surface morphology were improved significantly after the post-annealing process. Post-annealed ITO/Ag/Ni at 600 °C shows the best quality of TCE with figure-of-merit (FOM) of 1.5 × 10-2 Ω-1 and high optical transmittance of 83% at 470 nm as well as very low electrical resistivity of 4.3 × 10-5 Ω-cm. The crystalline quality and surface morphological plays an important role in determining the quality of the TCE multilayer thin films properties.

  15. Effect of addition of Ag nano powder on mechanical properties of epoxy/polyaminoamide adduct coatings filled with conducting polymer

    Energy Technology Data Exchange (ETDEWEB)

    Samad, Ubair Abdus [Department of Chemical Engineering, College of Engineering, King Saud University, P. O. Box 800, Riyadh 11421 (Saudi Arabia); Center of excellence for research in engineering materials (CEREM), Advance Manufacturing Institute, King Saud University, P. O. Box 800, Riyadh 11421 (Saudi Arabia); Khan, Rawaiz [Department of Chemical Engineering, College of Engineering, King Saud University, P. O. Box 800, Riyadh 11421 (Saudi Arabia); Alam, Mohammad Asif [Center of excellence for research in engineering materials (CEREM), Advance Manufacturing Institute, King Saud University, P. O. Box 800, Riyadh 11421 (Saudi Arabia); Al-Othman, Othman Y. [Department of Chemical Engineering, College of Engineering, King Saud University, P. O. Box 800, Riyadh 11421 (Saudi Arabia); Deanship of Graduate Studies, The Saudi Electric University, P. O. Box 93499, Riyadh 11673 (Saudi Arabia); Al-Zahrani, Saeed M. [Center of excellence for research in engineering materials (CEREM), Advance Manufacturing Institute, King Saud University, P. O. Box 800, Riyadh 11421 (Saudi Arabia); SABIC Polymer Research Center (SPRC) and department of chemical engineering, college of engineering, King Saud University, P. O. Box 800, Riyadh 11421 (Saudi Arabia)

    2015-05-22

    In this study the effect of Ag Nano powder on mechanical properties of epoxy coatings filled with optimized ratio of conducting polymers (Polyaniline and Polyppyrole) was evaluated. Bisphenol A diglycidyl ether epoxy resin (DGEBA) along with polyaminoamide adduct (ARADUR 3282-1 BD) is used as curing agent under optimized stoichiometry values. Curing is performed at room temperature with different percentages of Nano filler. Glass and steel panels were used as coating substrate. Bird applicator was used to coat the samples in order to obtain thin film with wet film thickness (WFT) of about 70-90 µm. The samples were kept in dust free environment for about 7 days at room temperature for complete curing. The coated steel panels were used to evaluate the mechanical properties of coating such as hardness, scratch and impact tests whereas coated glass panels were used for measuring pendulum hardness of the coatings. To check the dispersion and morphology of Nano filler in epoxy matrix scanning electron microscopy (SEM) was used in addition Nano indentation was also performed to observe the effect of Nano filler on modulus of elasticity and hardness at Nano scale.

  16. Does the number of nitrogen atoms have an influence on the conducting properties of diphenylazines? A DFT insight

    Science.gov (United States)

    Moral, Mónica; Granadino-Roldán, José Manuel; Garzón, Andrés; García, Gregorio; Fernández-Gómez, Manuel

    2011-01-01

    The present study reports on the variation of some structural and electronic properties related to the electron conductivity for the series of diphenylazines represented by the formula Ph sbnd (C 2+nN 4-nH n) sbnd Ph, n = 0 - 4. Properties such as planarity, aromaticity, HOMO → LUMO excitation energy, electron affinity, LUMO level energy, reorganization energy and electron coupling between neighboring molecules in the crystal were analyzed from a theoretical perspective as a function of the number of nitrogen atoms in the molecular structure. As a result, the planarity, aromaticity and electron affinity increase with the number of N atoms in the central ring while the HOMO → LUMO excitation energy and LUMO levels diminish. It is worth noting that up to n = 3, the frontier orbitals appear delocalized throughout the whole system while for n = 4 the localized character of the LUMO might explain the increase in the reorganization energy and thus the higher difficulty to delocalize the excess of negative charge. Electron coupling between neighboring molecules was also estimated on the basis of the energy splitting in dimer method and the reported crystal structures for some of the studied molecules. Accordingly, the highest | t12| value was obtained for Ph 2T N3 (0.06 eV) while Ph 2Tz should be the most advantageous candidate of the series in terms of electron injection.

  17. Artificial nacre-like papers based on noncovalent functionalized boron nitride nanosheets with excellent mechanical and thermally conductive properties.

    Science.gov (United States)

    Zeng, Xiaoliang; Ye, Lei; Yu, Shuhui; Li, Hao; Sun, Rong; Xu, Jianbin; Wong, Ching-Ping

    2015-04-21

    Inspired by the nano/microscale hierarchical structure and the precise inorganic/organic interface of natural nacre, we fabricated artificial nacre-like papers based on noncovalent functionalized boron nitride nanosheets (NF-BNNSs) and poly(vinyl alcohol) (PVA) via a vacuum-assisted self-assembly technique. The artificial nacre-like papers exhibit excellent tensile strength (125.2 MPa), on a par with that of the natural nacre, and moreover display a 30% higher toughness (2.37 MJ m(-3)) than that of the natural nacre. These excellent mechanical properties result from an ordered 'brick-and-mortar' arrangement of NF-BNNSs and PVA, in which the long-chain PVA molecules act as the bridge to link NF-BNNSs via hydrogen bonds. The resulting papers also render high thermal conductivity (6.9 W m(-1) K(-1)), and reveal their superiority as flexible substrates to support light-emitting-diode chips. The combined mechanical and thermal properties make the materials highly desirable as flexible substrates for next-generation commercial portable electronics.

  18. Effect of addition of Ag nano powder on mechanical properties of epoxy/polyaminoamide adduct coatings filled with conducting polymer

    International Nuclear Information System (INIS)

    Samad, Ubair Abdus; Khan, Rawaiz; Alam, Mohammad Asif; Al-Othman, Othman Y.; Al-Zahrani, Saeed M.

    2015-01-01

    In this study the effect of Ag Nano powder on mechanical properties of epoxy coatings filled with optimized ratio of conducting polymers (Polyaniline and Polyppyrole) was evaluated. Bisphenol A diglycidyl ether epoxy resin (DGEBA) along with polyaminoamide adduct (ARADUR 3282-1 BD) is used as curing agent under optimized stoichiometry values. Curing is performed at room temperature with different percentages of Nano filler. Glass and steel panels were used as coating substrate. Bird applicator was used to coat the samples in order to obtain thin film with wet film thickness (WFT) of about 70-90 µm. The samples were kept in dust free environment for about 7 days at room temperature for complete curing. The coated steel panels were used to evaluate the mechanical properties of coating such as hardness, scratch and impact tests whereas coated glass panels were used for measuring pendulum hardness of the coatings. To check the dispersion and morphology of Nano filler in epoxy matrix scanning electron microscopy (SEM) was used in addition Nano indentation was also performed to observe the effect of Nano filler on modulus of elasticity and hardness at Nano scale

  19. Effect of addition of Ag nano powder on mechanical properties of epoxy/polyaminoamide adduct coatings filled with conducting polymer

    Science.gov (United States)

    Samad, Ubair Abdus; Khan, Rawaiz; Alam, Mohammad Asif; Al-Othman, Othman Y.; Al-Zahrani, Saeed M.

    2015-05-01

    In this study the effect of Ag Nano powder on mechanical properties of epoxy coatings filled with optimized ratio of conducting polymers (Polyaniline and Polyppyrole) was evaluated. Bisphenol A diglycidyl ether epoxy resin (DGEBA) along with polyaminoamide adduct (ARADUR 3282-1 BD) is used as curing agent under optimized stoichiometry values. Curing is performed at room temperature with different percentages of Nano filler. Glass and steel panels were used as coating substrate. Bird applicator was used to coat the samples in order to obtain thin film with wet film thickness (WFT) of about 70-90 µm. The samples were kept in dust free environment for about 7 days at room temperature for complete curing. The coated steel panels were used to evaluate the mechanical properties of coating such as hardness, scratch and impact tests whereas coated glass panels were used for measuring pendulum hardness of the coatings. To check the dispersion and morphology of Nano filler in epoxy matrix scanning electron microscopy (SEM) was used in addition Nano indentation was also performed to observe the effect of Nano filler on modulus of elasticity and hardness at Nano scale.

  20. Quantification and impact of nonparabolicity of the conduction band of indium tin oxide on its plasmonic properties

    International Nuclear Information System (INIS)

    Liu, Xiaoge; Park, Junghyun; Kang, Ju-Hyung; Yuan, Hongtao; Cui, Yi; Hwang, Harold Y.; Brongersma, Mark L.

    2014-01-01

    Doped indium tin oxide (ITO) behaves as a Drude metal with a plasma frequency that is controlled by its free carrier density. In this work, we systematically tune this frequency across the mid-infrared range by annealing treatments in a reducing environment that produce high electron concentrations (∼10 21  cm −3 ). The changes in ITO's optical properties that result from the changes in carrier density are measured by attenuated total reflection measurements. These optical frequency measurements are complemented by Hall measurements to obtain a comprehensive picture of the Drude response of the ITO films. It was found that a complete description of the optical properties at very high carrier densities needs to account for the nonparabolicity of the conduction band of ITO and a reduced carrier mobility. More specifically, an increase in carrier concentration from 6.2 × 10 19  cm −3 to 1.4 × 10 21  cm −3 comes with a change of the effective electron mass from 0.35 m 0 to 0.53 m 0 and a decrease in the optical frequency mobility from about 20 cm 2  V −1  s −1 to 9 cm 2  V −1  s −1

  1. Investigation on Synthesis, Stability, and Thermal Conductivity Properties of Water-Based SnO2/Reduced Graphene Oxide Nanofluids

    Science.gov (United States)

    Yu, Xiaofen; Wu, Qibai; Zhang, Haiyan; Zeng, Guoxun; Li, Wenwu; Qian, Yannan; Li, Yang; Yang, Guoqiang; Chen, Muyu

    2017-01-01

    With the rapid development of industry, heat removal and management is a major concern for any technology. Heat transfer plays a critically important role in many sectors of engineering; nowadays utilizing nanofluids is one of the relatively optimized techniques to enhance heat transfer. In the present work, a facile low-temperature solvothermal method was employed to fabricate the SnO2/reduced graphene oxide (rGO) nanocomposite. X-ray diffraction (XRD), thermogravimetric analysis (TGA), X-ray photoelectron spectroscope (XPS), Raman spectroscopy, and transmission electron microscopy (TEM) have been performed to characterize the SnO2/rGO nanocomposite. Numerous ultrasmall SnO2 nanoparticles with average diameters of 3–5 nm were anchored on the surface of rGO, which contain partial hydrophilic functional groups. Water-based SnO2/rGO nanofluids were prepared with various weight concentrations by using an ultrasonic probe without adding any surfactants. The zeta potential was measured to investigate the stability of the as-prepared nanofluid which exhibited great dispersion stability after quiescence for 60 days. A thermal properties analyzer was employed to measure thermal conductivity of water-based SnO2/rGO nanofluids, and the results showed that the enhancement of thermal conductivity could reach up to 31% at 60 °C under the mass fraction of 0.1 wt %, compared to deionized water. PMID:29280972

  2. Effect of test temperature and strain rate on the tensile properties of high-strength, high-conductivity copper alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zinkle, S.J.; Eatherly, W.S. [Oak Ridge National Lab., TN (United States)

    1997-04-01

    The unirradiated tensile properties of wrought GlidCop AL25 (ITER grade zero, IGO) solutionized and aged CuCrZr, and cold-worked and aged and solutionized and aged Hycon 3HP{trademark} CuNiBe have been measured over the temperature range of 20-500{degrees}C at strain rates between 4 x 10{sup {minus}4} s{sup {minus}1} and 0.06 s{sup {minus}1}. The measured room temperature electrical conductivity ranged from 64 to 90% IACS for the different alloys. All of the alloys were relatively insensitive to strain rate at room temperature, but the strain rate sensitivity of GlidCop Al25 increased significantly with increasing temperature. The CuNiBe alloys exhibited the best combination of high strength and high conductivity at room temperature. The strength of CuNiBe decreased slowly with increasing temperature. However, the ductility of CuNiBe decreased rapidly with increasing temperature due to localized deformation near grain boundaries, making these alloy heats unsuitable for typical structural applications above 300{degrees}C. The strength and uniform elongation of GlidCop Al25 decreased significantly with increasing temperature at a strain rate of 1 x 10{sup {minus}3} s{sup {minus}1}, whereas the total elongation was independent of test temperature. The strength and ductility of CuCrZr decreased slowly with increasing temperature.

  3. AC/DC electrical conduction and dielectric properties of PMMA/PVAc/C60 down-shifting nanocomposite films

    Science.gov (United States)

    El-Bashir, S. M.; Alwadai, N. M.; AlZayed, N.

    2018-02-01

    Polymer nanocomposite films were prepared by doping fullerene C60 in polymer blend composed of polymethacrylate/polyvinyl acetate blends (PMMA/PVAc) using solution cast technique. The films were characterized by differential scanning calorimeter (DSC), Transmission electron microscope (TEM), DC/AC electrical conductivity and dielectric measurements in the frequency range (100 Hz- 1 MHz). The glass transition temperature, Tg, was increased by increasing the concentration of fullerene C60; this property reflects the increase of thermal stability by increasing the nanofiller content. The DC and AC electrical conductivities were enhanced by increasing C60 concentration due to the electron hopping or tunneling between filled and empty localized states above Tg. The relaxation time was determined from the αβ -relaxations and found to be attenuated by increasing the temperature as a typical behavior of amorphous polymers. The calculated values of thermodynamic parameters revealed the increase of molecular stability by increasing the doping concentration; this feature supports the application of PMMA/PVAc/C60 nanocomposite films in a wide scale of solar energy conversion applications such as luminescent down-shifting (LDS) coatings for photovoltaic cells.

  4. Influences of Structure Disorder and Temperature on Properties of Proton Conductivity in Hydrogen-Bond Molecular Systems

    Institute of Scientific and Technical Information of China (English)

    PANG Xiao-Feng; YU Jia-Feng

    2007-01-01

    The dynamic properties of proton conductivity along hydrogen-bonded molecular systems,for example,ice crystal,with structure disorder or damping and finite temperatures exposed in an externally applied electric-field have been numerically studied by Runge-Kutta way in our Soliton model.The results obtained show that the proton-soliton is very robust against the structure disorder including the fluctuation of the force constant and disorder in the sequence of masses and thermal perturbation and damping of medium,the velocity of its conductivity increases with increasing of the externally applied electric-field and decreasing of the damping coefficient of medium,but the proton-soliton disperses for quite great fluctuation of the force constant and damping coefficient.In the numerical simulation we find that the proton-soliton in our model is thermally stable in a large region of temperature of T ≤ 273 K under influences of damping and externally applied electric-field in ice crystal.This shows that our model is available and appropriate to ice.

  5. Effect of surface states of layered double hydroxides on conductive and transport properties of nanocomposite polymer electrolytes

    International Nuclear Information System (INIS)

    Liao, C.-S.; Ye, W.-B.

    2004-01-01

    All solid-state poly(ethylene oxide) (PEO) nanocomposite electrolytes were made containing nanoscale fillers of layered double hydroxides (LDHs). Two kinds of LDHs with different surface states were prepared by aqueous co-precipitation method. The LDHs were added into PEO matrix to study the structures, conductivities and ionic transport properties of nanocomposite electrolytes. The structures of LDHs were characterized by infrared spectra, thermogravimetric analysis and wide-angle X-ray diffraction. With enhanced compatibility of LDH sheets by oligo(ethylene oxide) surface modification, the PEO/OMLDH nanocomposite electrolyte exhibits an amorphous morphology and an enhancement of conductivity by three orders of magnitude as compared to pure PEO electrolyte. The lithium ion transference number T Li + of PEO/LDH nanocomposite electrolyte measured with a value of 0.42 is two times higher than the one of pure PEO electrolyte, which can be attributed to the Lewis acid-base interaction between surface states of metal hydroxides and counter anions of lithium salts

  6. AC conductivity and dielectric properties of amorphous GexSb40-xSe60 thin films

    International Nuclear Information System (INIS)

    Atyia, H.E.; Farid, A.M.; Hegab, N.A.

    2008-01-01

    Measurements of AC conductivity and dielectric properties have been made for chalcogenide film samples of Ge x Sb 40-x Se 60 (with x=0, 10 and 20 at%) at different temperatures (303-393 K) and various frequencies (10 2 -10 5 Hz). It was found that the AC conductivity obeys the law σ(ω, T)=Aω s . The exponent s 1 and dielectric loss ε 2 were found to decrease with frequency and increase with temperature. The maximum barrier height W M was calculated from dielectric measurements according to the Guintini equation. It was found that the obtained value of W m agrees with that proposed by the theory of hopping of charge carriers over potential barrier as suggested by Elliott in case of chalcogenide glasses. The density of localized states N(E F ) has also been calculated for the studied compositions. The effect of decreasing the Sb content at the expense of the Ge content was investigated for the obtained results of the studied parameters

  7. Investigation on Synthesis, Stability, and Thermal Conductivity Properties of Water-Based SnO2/Reduced Graphene Oxide Nanofluids

    Directory of Open Access Journals (Sweden)

    Xiaofen Yu

    2017-12-01

    Full Text Available With the rapid development of industry, heat removal and management is a major concern for any technology. Heat transfer plays a critically important role in many sectors of engineering; nowadays utilizing nanofluids is one of the relatively optimized techniques to enhance heat transfer. In the present work, a facile low-temperature solvothermal method was employed to fabricate the SnO2/reduced graphene oxide (rGO nanocomposite. X-ray diffraction (XRD, thermogravimetric analysis (TGA, X-ray photoelectron spectroscope (XPS, Raman spectroscopy, and transmission electron microscopy (TEM have been performed to characterize the SnO2/rGO nanocomposite. Numerous ultrasmall SnO2 nanoparticles with average diameters of 3–5 nm were anchored on the surface of rGO, which contain partial hydrophilic functional groups. Water-based SnO2/rGO nanofluids were prepared with various weight concentrations by using an ultrasonic probe without adding any surfactants. The zeta potential was measured to investigate the stability of the as-prepared nanofluid which exhibited great dispersion stability after quiescence for 60 days. A thermal properties analyzer was employed to measure thermal conductivity of water-based SnO2/rGO nanofluids, and the results showed that the enhancement of thermal conductivity could reach up to 31% at 60 °C under the mass fraction of 0.1 wt %, compared to deionized water.

  8. Influences of Structure Disorder and Temperature on Properties of Proton Conductivity in Hydrogen-Bond Molecular Systems

    International Nuclear Information System (INIS)

    Pang Xiaofeng; Yu Jiafeng

    2007-01-01

    The dynamic properties of proton conductivity along hydrogen-bonded molecular systems, for example, ice crystal, with structure disorder or damping and finite temperatures exposed in an externally applied electric-field have been numerically studied by Runge-Kutta way in our soliton model. The results obtained show that the proton-soliton is very robust against the structure disorder including the fluctuation of the force constant and disorder in the sequence of masses and thermal perturbation and damping of medium, the velocity of its conductivity increases with increasing of the externally applied electric-field and decreasing of the damping coefficient of medium, but the proton-soliton disperses for quite great fluctuation of the force constant and damping coefficient. In the numerical simulation we find that the proton-soliton in our model is thermally stable in a large region of temperature of T≤273 K under influences of damping and externally applied electric-field in ice crystal. This shows that our model is available and appropriate to ice.

  9. Effect of variation in the glass-former network structure on the relaxation properties of conductive Ag+ ions in AgI-based fast ion conducting glasses

    Science.gov (United States)

    Hanaya, Minoru; Nakayama, Michiko; Hatate, Atsuo; Oguni, Masaharu

    1995-08-01

    Heat capacities and ac conductivities of AgI-based fast ion conducting glasses of AgI-Ag2O-P2O5 and AgI-Ag2O-B2O3 systems with different P-O or B-O network structures but with the same AgI concentration of 1.55×104 mol m-3 were measured in the temperature range 14-400 K and in the temperature and frequency ranges 100-200 K and 10 Hz-1 MHz, respectively. The β-glass transition due to a freezing-in of the rearrangement of Ag+ ions was observed by adiabatic calorimetry for the glasses in the liquid-nitrogen temperature region, and the conductometry was suggested to see the same mode of Ag+-ion motion as the calorimetry. It was found that the development of the network structure of the glass former at constant AgI concentration resulted in the decrease of the β-glass transition temperature and the activation energy for the diffusional motion of Ag+ ions and in the increase of the heat-capacity jump associated with the glass transition. The results support the amorphous AgI aggregate model for the structure of the conductive region in the glasses with relatively high AgI compositions, indicating that Ag+-ion conductivity is mainly dominated by the degree of development of the AgI aggregate region dependent on the glass-former network structure as well as the AgI composition.

  10. Study of transport properties and conduction mechanism of pure and composite resorcinol formaldehyde aerogel doped with Co-ferrite

    International Nuclear Information System (INIS)

    Attia, S.M.; Sharshar, T.; Abd-Elwahed, A.R.; Tawfik, A.

    2013-01-01

    Highlights: • A novel composite RF aerogels with Co-ferrite were prepared by sol–gel process. • RF aerogels exhibit a semiconducting behavior. • The dielectric constant of RF aerogel is very low (4 times as that of air) and can be controlled by adding Co-ferrite. • Large overlapping polaron (OLP) was found to be the preferred conduction mechanism in these materials. -- Abstract: A series of resorcinol formaldehyde aerogels (RF aerogels) composite with nanoparticles of CoFe 2 O 4 have been prepared by sol–gel method. Four samples of pure RF aerogels were prepared at different concentrations of Na 2 CO 3 as catalyst (0.02, 0.025, 0.03, and 0.04 wt.%) and four samples of composite RF aerogels were prepared at different concentration of doped CoFe 2 O 4 (0.075, 0.1, 0.125, and 0.15 wt.%; Na 2 CO 3 concentration = 0.03 wt.%). DC electrical conductivity as a function of temperature was studied in the temperature range 25 °C–200 °C for all samples. AC electrical conductivity and dielectric properties were determined using RLC Bridge in the frequency range 100 Hz–1 MHz at different temperature (25–200 °C). The pore size of the samples was determined using positron annihilation lifetime spectroscopy (PALS). RF aerogels are found to exhibit a semiconducting behavior and characterized by two transition temperatures T 1 and T 2 . Also σ DC increases with increase of Co-ferrite contents. Pure RF aerogels posses a very low dielectric constant, where the lowest value of ε′ is ∼4 times as that of air. ε′ decreases with increase of frequency, and increases with increase of temperature. Large overlapping polaron (OLP) is found to be the preferred conduction mechanism in these materials. The results of PALS show that there are two types of pore size in these samples; the first ranges from 1.9 to 2.5 nm, while the second ranges from 3.2 to 5.3 nm

  11. Effects of laser-induced recovery process on conductive property of SnO2:F thin films

    International Nuclear Information System (INIS)

    Chen, Ming-Fei; Lin, Keh-moh; Ho, Yu-Sen

    2011-01-01

    In this study, we developed a laser annealing process to enhance the electrical properties of SnO 2 :F (FTO) films. It is already known that in contrast to indium oxides or zinc oxides, the carrier mobility of FTO films is relatively lower. Thus, improving the mobility is a direct way to enhance the conductivity of FTO films. Furthermore, improving the crystal quality of the thin films is in turn a direct way to enhance the mobility effectively. Contrary to the high working temperatures of traditional annealing processes, the laser annealing process, with its focusing character, enables us to modify the crystal quality of oxide films on substrates with low-melting points. Using a self-built laser system, which consists of a Nd:YAG solid-state laser with a wavelength of 1064 nm and a beam shaper lens, we carried out a series of experiments to achieve the optimal laser annealing process. Hall, SEM, and XRD measurements were used to characterize the opto-electrical as well as the structural properties. As experimental results show, the tin oxide crystallites recovered well during the laser annealing process. By using a suitable beam profile and a proper laser intensity, the film resistivity was reduced from 7.19 ± 0.55 x 10 -3 Ω cm to 6.70 ± 0.20 x 10 -3 Ω cm while the carrier mobility was enhanced from 11.18 ± 0.29 cm 2 /V s to 11.71 ± 0.34 cm 2 /V s.

  12. Does the number of nitrogen atoms have an influence on the conducting properties of diphenylazines? A DFT insight

    International Nuclear Information System (INIS)

    Moral, Monica; Granadino-Roldan, Jose Manuel; Garzon, Andres; Garcia, Gregorio; Fernandez-Gomez, Manuel

    2011-01-01

    Research highlights: → Planarity and aromaticity increase when increasing the number of N atoms. → HOMO → LUMO excitation energy decreases when increasing the number of N atoms. → AEA increases stepwise with the number of N atoms up to 1.51 eV for Ph 2 Tz. → Ph 2 Tz becomes the best candidate of the series in terms of electron injection. → Ph 2 T N3 seems to be the best candidate in terms of electron transport. - Abstract: The present study reports on the variation of some structural and electronic properties related to the electron conductivity for the series of diphenylazines represented by the formula Ph-(C 2+n N 4-n H n )-Ph, n = 0 - 4. Properties such as planarity, aromaticity, HOMO → LUMO excitation energy, electron affinity, LUMO level energy, reorganization energy and electron coupling between neighboring molecules in the crystal were analyzed from a theoretical perspective as a function of the number of nitrogen atoms in the molecular structure. As a result, the planarity, aromaticity and electron affinity increase with the number of N atoms in the central ring while the HOMO → LUMO excitation energy and LUMO levels diminish. It is worth noting that up to n = 3, the frontier orbitals appear delocalized throughout the whole system while for n = 4 the localized character of the LUMO might explain the increase in the reorganization energy and thus the higher difficulty to delocalize the excess of negative charge. Electron coupling between neighboring molecules was also estimated on the basis of the energy splitting in dimer method and the reported crystal structures for some of the studied molecules. Accordingly, the highest |t 12 | value was obtained for Ph 2 T N3 (0.06 eV) while Ph 2 Tz should be the most advantageous candidate of the series in terms of electron injection.

  13. A Preliminary Study of the Application of Electromagnetic Conductivity Meter on Soil Properties of Paddy Cultivation Areas at Wue Village, Jantho, Aceh Besar District, Indonesia

    OpenAIRE

    Marwan,

    2015-01-01

    Conventional soil sampling is time consuming and requires meticulous laboratory analysis. Hence, mapping of soil apparent in respect to electrical conductivity (ECa) has been developed to identify areas of contrasting soil properties. Such ECa values are represent measures of soil properties. The sensor system, GF Instrument model CMD-4 were used to analyze soil physical properties. This system consists of three important parts, ECa sensor, data logger and Global Positioning System (DGPS) rec...

  14. Positivity for Convective Semi-discretizations

    KAUST Repository

    Fekete, Imre; Ketcheson, David I.; Loczi, Lajos

    2017-01-01

    We propose a technique for investigating stability properties like positivity and forward invariance of an interval for method-of-lines discretizations, and apply the technique to study positivity preservation for a class of TVD semi-discretizations

  15. Optical and electrical properties of transparent conductive ITO thin films under proton radiation with 100 keV

    International Nuclear Information System (INIS)

    Wei, Q.; He, S.Y.; Yang, D.Z.; Liu, J.C.

    2005-01-01

    Under the simulation environment for the vacuum and heat sink in space, the changes in optical and electrical properties of transparent conductive indium tin oxide (ITO) thin films induced by radiation of protons with 100 keV were studied. The ITO thin films were deposited on JGS1 quartz substrate by a sol-gel method. The sheet resistance and transmittance spectra of the ITO thin films were measured using the four-point probe method and a spectrophotometer, respectively. The surface morphology was analyzed by AFM. The experimental results showed that the electrical and optical performances of the ITO thin films were closely related to the irradiation fluence. When the fluence exceeded a given value 2 x 10 16 cm -2 , the sheet resistance increased obviously and the optical transmittance decreased. The AFM analysis indicated that the grain size of the ITO thin films diminished. The studies about the radiation effect on ITO thin films will help to predict performance evolution of the second surface mirrors on satellites under space radiation environment. (orig.)

  16. Electrochemical properties and electrocatalytic activity of conducting polymer/copper nanoparticles supported on reduced graphene oxide composite

    Science.gov (United States)

    Ehsani, Ali; Jaleh, Babak; Nasrollahzadeh, Mahmoud

    2014-07-01

    Reduced graphene oxide (rGO) was used to support Cu nanoparticles. As electro-active electrodes for supercapacitors composites of reduced graphene oxide/Cu nanoparticles (rGO/CuNPs) and polytyramine (PT) with good uniformity are prepared by electropolymerization. Composite of rGO/CuNPs-PT was synthesized by cyclic voltammetry (CV) methods and electrochemical properties of film were investigated by using electrochemical techniques. The results show that, the rGO/CuNPs-PT/G has better capacitance performance. This is mainly because of the really large surface area and the better electronic and ionic conductivity of rGO/CuNPs-PT/G, which lead to greater double-layer capacitance and faradic pseudo capacitance. Modified graphite electrodes (rGO/CuNPs-PT/G) were examined for their redox process and electrocatalytic activities towards the oxidation of methanol in alkaline solutions. The methods of cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) were employed. In comparison with a Cu-PT/G (Graphite), rGO/CuNPs-PT/G modified electrode shows a significantly higher response for methanol oxidation. A mechanism based on the electro-chemical generation of Cu(III) active sites and their subsequent consumptions by methanol have been discussed.

  17. Properties of transparent and conductive Al:ZnO/Au/Al:ZnO multilayers on flexible PET substrates

    International Nuclear Information System (INIS)

    Dimopoulos, T.; Bauch, M.; Wibowo, R.A.; Bansal, N.; Hamid, R.; Auer, M.; Jäger, M.; List-Kratochvil, E.J.W.

    2015-01-01

    Highlights: • Transparent, low resistive AZO/Au/AZO layers were sputtered on PET substrates. • AZO/Au/AZO has higher figure of merit than ITO for specific Au thicknesses. • The resistance of AZO/Au/AZO is stable against repetitive substrate bending. • AZO/Au/AZO electrode performance is comparable to ITO in light emitting diodes. - Abstract: We investigate the structural, electrical and optical properties of transparent electrodes, consisting of Al-doped ZnO (AZO) and ultrathin Au layers, sputtered on polyethylene terephthalate (PET). These electrodes are relevant for optoelectronic devices and thin film photovoltaics. When deposited on AZO, Au films as thin as 3 nm form electrically conductive, meandering structures, whereas uniform Au films are obtained from a thickness of 5 nm. The sheet resistance decreases with Au thickness, reaching 7 Ω for 11 nm-thick Au. AZO/Au/AZO trilayers combine lowest resistance with highest transparency, while their resistance stability against bending fatigue is superior to the Sn-doped In 2 O 3 (ITO) electrode. The figure of merit of AZO/Au/AZO is larger than of ITO for Au thickness equal to or larger than 9 nm. To demonstrate the applicability of the AZO/Au/AZO transparent electrode, simple organic light emitting diodes were fabricated and tested in comparison to PET/ITO standard substrates

  18. Properties of transparent and conductive Al:ZnO/Au/Al:ZnO multilayers on flexible PET substrates

    Energy Technology Data Exchange (ETDEWEB)

    Dimopoulos, T., E-mail: theodoros.dimopoulos@ait.ac.at [AIT-Austrian Institute of Technology, Energy Department, Photovoltaic Systems, Giefinggasse 2, 1210, Vienna (Austria); Bauch, M.; Wibowo, R.A.; Bansal, N. [AIT-Austrian Institute of Technology, Energy Department, Photovoltaic Systems, Giefinggasse 2, 1210, Vienna (Austria); Hamid, R. [AIT-Austrian Institute of Technology, Mobility Department, Electric Drive Technologies, Giefinggasse 2, 1210, Vienna (Austria); Auer, M.; Jäger, M. [NanoTecCenter Weiz Forschungsgesellschaft mbH, Franz-Pichler Straße 32, A-8160 Weiz (Austria); List-Kratochvil, E.J.W. [NanoTecCenter Weiz Forschungsgesellschaft mbH, Franz-Pichler Straße 32, A-8160 Weiz (Austria); Institute of Solid State Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz (Austria)

    2015-10-15

    Highlights: • Transparent, low resistive AZO/Au/AZO layers were sputtered on PET substrates. • AZO/Au/AZO has higher figure of merit than ITO for specific Au thicknesses. • The resistance of AZO/Au/AZO is stable against repetitive substrate bending. • AZO/Au/AZO electrode performance is comparable to ITO in light emitting diodes. - Abstract: We investigate the structural, electrical and optical properties of transparent electrodes, consisting of Al-doped ZnO (AZO) and ultrathin Au layers, sputtered on polyethylene terephthalate (PET). These electrodes are relevant for optoelectronic devices and thin film photovoltaics. When deposited on AZO, Au films as thin as 3 nm form electrically conductive, meandering structures, whereas uniform Au films are obtained from a thickness of 5 nm. The sheet resistance decreases with Au thickness, reaching 7 Ω for 11 nm-thick Au. AZO/Au/AZO trilayers combine lowest resistance with highest transparency, while their resistance stability against bending fatigue is superior to the Sn-doped In{sub 2}O{sub 3} (ITO) electrode. The figure of merit of AZO/Au/AZO is larger than of ITO for Au thickness equal to or larger than 9 nm. To demonstrate the applicability of the AZO/Au/AZO transparent electrode, simple organic light emitting diodes were fabricated and tested in comparison to PET/ITO standard substrates.

  19. Heat transfer study on convective–radiative semi-spherical fins with temperature-dependent properties and heat generation using efficient computational methods

    International Nuclear Information System (INIS)

    Atouei, S.A.; Hosseinzadeh, Kh.; Hatami, M.; Ghasemi, Seiyed E.; Sahebi, S.A.R.; Ganji, D.D.

    2015-01-01

    In this study, heat transfer and temperature distribution equations for semi-spherical convective–radiative porous fins are presented. Temperature-dependent heat generation, convection and radiation effects are considered and after deriving the governing equation, Least Square Method (LSM), Collocation Method (CM) and fourth order Runge-Kutta method (NUM) are applied for predicting the temperature distribution in the described fins. Results reveal that LSM has excellent agreement with numerical method, so can be suitable analytical method for solving the problem. Also, the effect of some physical parameters which are appeared in the mathematical formulation on fin surface temperature is investigated to show the effect of radiation and heat generation in a solid fin temperature. - Highlights: • Thermal analysis of a semi-spherical fin is investigated. • Collocation and Least Square Methods are applied on the problem. • Convection, radiation and heat generation is considered. • Physical results are compared to numerical outcomes.

  20. Thermoelectric Properties of Silicon Germanium: An Investigation of the Reduction of Lattice Thermal Conductivity and Enhancement of Power Factor

    Science.gov (United States)

    Lahwal, Ali Sadek

    theoretical density. At room temperature, we observed approximately a 50% reduction in the lattice thermal conductivity as result of adding 10 volume % YSZ to the Si80Ge 20P2 host matrix. A phenomenological Callaway model was used to corroborate both the temperature dependence and the reduction of kappaL over the measured temperature range (30--800K) of both Si80Ge 20P2 and Si80 Ge20P2 + YSZ samples. The observed kappaL is discussed and interpreted in terms of various phonon scattering mechanisms including alloy disorder, the Umklapp process, and boundary scattering. Specifically, a contribution from the phonon scattering by YSZ nanoparticles was further included to account for the kappaL of Si80Ge20P 2 +YSZ samples. In addition, a core shell treatment was applied onto p-type SiGe. Ball milled Si80Ge 20B1.7 alloys were coated with YSZ with different thicknesses and characterized upon their thermoelectric properties. The results show that YSZ coatings are capable of greatly reducing the thermal conductivity especially the lattice thermal conductivity. These coatings are applied directly onto mechanical alloyed (MA), p-type SiGe. The only concern about the YSZ core shelling is that these coatings turned out to be too thick degrading the electrical conductivity of the material. Our second approach, in a parallel work, is to enhance the thermoelectric power factor as well as the dimensionless figure of merit ZT of: (i) single element spark plasma sintered (SE SPS) SiGe alloys. (ii) ball milled (BM) SiGe , via sodium boron hydrate (NaBH4) alkali-metal-salt treatment. Sodium boron hydrate alkali-metal-salt thermally decomposes (decompose temperature 600 ˜ 700 K) to elemental solid sodium, solid boron, and hydrogen gas, as binary phases, e.g., Na-B or Na-H, or as a ternary phase, Na- B-H. Upon SPS at 1020 K, it is inferred that Na dopes SiGe while forming Na 2B29 phase, leading to a reduction in the electrical resistivity without much degrading the Seebeck coefficient, consequently

  1. Study of strength properties of semi-finished products from economically alloyed high-strength aluminium-scandium alloys for application in automobile transport and shipbuilding

    Science.gov (United States)

    Baranov, Vladimir; Sidelnikov, Sergey; Zenkin, Evgeny; Frolov, Viktor; Voroshilov, Denis; Yakivyuk, Olga; Konstantinov, Igor; Sokolov, Ruslan; Belokonova, Irina

    2018-04-01

    The results of a study on the strength of rolled products from aluminium alloys doped with scandium under various processing conditions of hot and cold rolling are presented. The regularities of metal flow and the level of strength of deformed semi-finished products from aluminum-scandium alloys are established, depending on the total degree of deformation and the various modes of single reduction during rolling. It is shown that when using one heating of a cast billet to obtain high-quality semi-finished products, the temperature during the rolling process should not be lower than 350-370°, and the total degree of deformation does not exceed 50-60%. It was found that the semi-finished products from alloys with a content of scandium in the range 0.11-0.12% in the deformed state had elevated values of ultimate tensile strength and yield strength of the metal, which allows them to be recommended for industrial production of sheet metal products.

  2. Influence wt.% of SiC and borax on the mechanical properties of AlSi-Mg-TiB-SiC composite by the method of semi solid stir casting

    Science.gov (United States)

    Bhiftime, E. I.; Guterres, Natalino F. D. S.; Haryono, M. B.; Sulardjaka, Nugroho, Sri

    2017-04-01

    SiC particle reinforced metal matrix composites (MMCs) with solid semi stir casting method is becoming popular in recent application (automotive, aerospace). Stirring the semi solid condition is proven to enhance the bond between matrix and reinforcement. The purpose of this study is to investigate the effect of the SiC wt.% and the addition of borax on mechanical properties of composite AlSi-Mg-TiB-SiC and AlSi-Mg-TiB-SiC/Borax. Specimens was tested focusing on the density, porosity, tensile test, impact test microstructure and SEM. AlSi is used as a matrix reinforced by SiC with percentage variations (10, 15, 20 wt.%). Giving wt.% Borax which is the ratio of 1: 4 between wt.% SiC. The addition of 1.5% of TiB gives grain refinement. The use of semi-solid stir casting method is able to increase the absorption of SiC particles into a matrix AlSi evenly. The improved composite presented here can be used as a guideline to make a new composite.

  3. Optical spectroscopy, optical conductivity, dielectric properties and new methods for determining the gap states of CuSe thin films

    International Nuclear Information System (INIS)

    Sakr, G.B.; Yahia, I.S.; Fadel, M.; Fouad, S.S.; Romcevic, N.

    2010-01-01

    Research highlights: → The structural, optical dispersion parameters and the Raman spectroscopy have been studied for CuSe thin films. → X-ray diffraction results indicate the amorphous nature of the thermally evaporated CuSe thin films. → The refractive index shows an anomalous dispersion at the lower wavelength (absorption region) and a normal dispersion at the higher wavelengths (transparent region). → The refractive index dispersion obeys the single oscillator model proposed by Wemple and DiDomenico WDD model and the single oscillator parameters were determined. → The band gap of CuSe thin films was determined by three novel methods i.e. (relaxation time, real and imaginary dielectric constant and real and imaginary optical conductivity) which in a good agreement with the Tauc band gap value. - Abstract: The paper describes the structural and optical properties of CuSe thin films. X-ray diffraction pattern indicates that CuSe thin film has an amorphous structure. Transmittance T(λ) and reflectance R(λ) measurements in the wavelength range (300-1700 nm) were used to calculate the refractive index n(λ), the absorption index and the optical dispersion parameters according to Wemple and Didomenico WDD model. The dispersion curve of the refractive index shows an anomalous dispersion in the absorption region and a normal dispersion in the transparent region. The optical bandgap has been estimated and confirmed by four different methods. The value for the direct bandgap for the as-deposited CuSe thin film approximately equals 2.7 eV. The Raman spectroscopy was used to identify and quantify the individual phases presented in the CuSe films.

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

    Directory of Open Access Journals (Sweden)

    Nicola H. Perry

    2016-10-01

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

  5. EFFECT OF COMMERCIALLY MANUFACTURED KAPPA SEMI-REFINED CARRAGEENAN (SRC WITH DIFFERENT PHOSPHATE SALTS ON YIELD, TEXTURAL AND SENSORY PROPERTIES OF BEEF MEAT

    Directory of Open Access Journals (Sweden)

    Marimuthu Murugesan

    2016-06-01

    Full Text Available The phosphate salts such as SDP, TSP, SHMP, DSP, TPPP, TKPP and STPP were blended with semi-refined kappa carrageenan (SRC individually and their aqueous solution was injected into the fresh beef meat. The highest weight gain (24% in fresh meat was obtained from injection of blend made with SRC and STPP as compared to other blends and control sample after forzen storage. Similarly, it also showed low cooking loss (24% with good testural and sensory proerties as compared to other blends. It can be concluded from the presnt study that blend of SRC and STPP can be used in beef meat for yield and quality improvement.

  6. Thermal conductivity, bulk properties, and thermal stratigraphy of silicic tuffs from the upper portion of hole USW-G1, Yucca Mountain, Nye County, Nevada

    International Nuclear Information System (INIS)

    Lappin, A.R.; VanBuskirk, R.G.; Enniss, D.O.; Buters, S.W.; Prater, F.M.; Muller, C.B.; Bergosh, J.L.

    1982-03-01

    Thermal-conductivity and bulk-property measurements were made on welded and nonwelded silicic tuffs from the upper portion of Hole USW-G1, located near the southwestern margin of the Nevada Test Site. Bulk-property measurements were made by standard techniques. Thermal conductivities were measured at temperatures as high as 280 0 C, confining pressures to 10 MPa, and pore pressures to 1.5 MPa. Extrapolation of measured saturated conductivities to zero porosity suggests that matrix conductivity of both zeolitized and devitrified tuffs is independent of stratigraphic position, depth, and probably location. This fact allows development of a thermal-conductivity stratigraphy for the upper portion of Hole G1. Estimates of saturated conductivities of zeolitized nonwelded tuffs and devitrified tuffs below the water table appear most reliable. Estimated conductivities of saturated densely welded devitrified tuffs above the water table are less reliable, due to both internal complexity and limited data presently available. Estimation of conductivity of dewatered tuffs requires use of different air thermal conductivities in devitrified and zeolitized samples. Estimated effects of in-situ fracturing generally appear negligible

  7. Multivariate semi-logistic distribution and processes | Umar | Journal ...

    African Journals Online (AJOL)

    Multivariate semi-logistic distribution is introduced and studied. Some characterizations properties of multivariate semi-logistic distribution are presented. First order autoregressive minification processes and its generalization to kth order autoregressive minification processes with multivariate semi-logistic distribution as ...

  8. Langmuir–Blodgett films based on poly(p-phenylene vinylene) and protein-stabilised palladium nanoparticles: Implications in luminescent and conducting properties

    Energy Technology Data Exchange (ETDEWEB)

    Goto, Thiago E.; Sakai, Andrei [Institute of Environmental, Chemical and Pharmaceutical Sciences, Federal University of São Paulo, Diadema, SP 09972-270 (Brazil); Iost, Rodrigo M. [Institute of Chemistry of de São Carlos, University of São Paulo, São Carlos, SP 13560-970 (Brazil); Silva, Welter C. [Center of Nature Sciences, Federal University of Piauí, Teresina, PI 64049-550 (Brazil); Crespilho, Frank N. [Institute of Chemistry of de São Carlos, University of São Paulo, São Carlos, SP 13560-970 (Brazil); Péres, Laura O. [Institute of Environmental, Chemical and Pharmaceutical Sciences, Federal University of São Paulo, Diadema, SP 09972-270 (Brazil); Caseli, Luciano, E-mail: lcaseli@unifesp.br [Institute of Environmental, Chemical and Pharmaceutical Sciences, Federal University of São Paulo, Diadema, SP 09972-270 (Brazil)

    2013-07-01

    In this paper, poly(p-phenylene vinylene) block copolymers (PPV) were immobilised in stearic acid (HSt) Langmuir–Blodgett (LB) films, and their conducting and luminescent properties were enhanced by the incorporation of palladium nanoparticles stabilised by glucose oxidase (GOx-PdNPs). The nanobiocomposite, based on HSt, PPV, and GOx-PdNPs, was transferred from the air-water interface onto solid supports using the LB technique. The films were characterised by surface pressure–area isotherms, polarisation modulation infrared reflection–absorption spectroscopy, fluorescence spectroscopy, and conductivity measurements. The results indicated that the incorporation of GOx-PdNPs in PPV-HSt LB films enhances the luminescence and conducting properties of the PPV. Based on the higher conductivity and emission obtained with the hybrid LB films and the ability to tune the molecular-level interactions between the film components by changing the experimental conditions, thus allowing for further optimisation, one may envisage applications for these films in optical and electronic devices, such as organic light-emitting diodes. - Highlights: • Palladium nanoparticles were introduced in conducting polymer-fatty acid monolayers. • Hybrid films were characterised with tensiometry and infrared spectroscopy. • Films were transferred to solid supports with the Langmuir–Blodgett technique. • Nanoparticles enhanced luminescence and conducting properties.

  9. Thermo-Mechanical Properties of Semi-Degradable Poly(β-amino ester)-co-Methyl Methacrylate Networks under Simulated Physiological Conditions

    Science.gov (United States)

    Safranski, David L.; Crabtree, Jacob C.; Huq, Yameen R.; Gall, Ken

    2011-01-01

    Poly(β-amino ester) networks are being explored for biomedical applications, but they may lack the mechanical properties necessary for long term implantation. The objective of this study is to evaluate the effect of adding methyl methacrylate on networks' mechanical properties under simulated physiological conditions. The networks were synthesized in two parts: (1) a biodegradable crosslinker was formed from a diacrylate and amine, (2) and then varying concentrations of methyl methacrylate were added prior to photopolymerizing the network. Degradation rate, mechanical properties, and glass transition temperature were studied as a function of methyl methacrylate composition. The crosslinking density played a limited role on mechanical properties for these networks, but increasing methyl methacrylate concentration improved the toughness by several orders of magnitude. Under simulated physiological conditions, networks showed increasing toughness or sustained toughness as degradation occurred. This work establishes a method of creating degradable networks with tailorable toughness while undergoing partial degradation. PMID:21966028

  10. Ga and Al doped zinc oxide thin films for transparent conducting oxide applications: Structure-property correlations

    Science.gov (United States)

    Temizer, Namik K.; Nori, Sudhakar; Narayan, Jagdish

    2014-01-01

    We report a detailed investigation on the structure-property correlations in Ga and Al codoped ZnO films on c-sapphire substrates where the thin film microstructure varies from nanocrystalline to single crystal. We have achieved highly epitaxial films with very high optical transmittance (close to 90%) and low resistivity (˜110 μΩ-cm) values. The films grown in an ambient oxygen partial pressure (PO2) of 5 × 10-2 Torr and at growth temperatures from room temperature to 600 °C show semiconducting behavior, whereas samples grown at a PO2 of 1 × 10-3 Torr show metallic nature. The most striking feature is the occurrence of resistivity minima at relatively high temperatures around 110 K in films deposited at high temperatures. The measured optical and transport properties were found to be a strong function of growth conditions implying that the drastic changes are brought about essentially by native point defects. The structure-property correlations reveal that point defects play an important role in modifying the structural, optical, electrical, and magnetic properties and such changes in physical properties are controlled predominantly by the defect content.

  11. Amorphous Fast Ion Conducting Systems, Part 1. Structure and Properties of Mid and Far IR Transmitting Materials, Part 2

    Science.gov (United States)

    1991-10-31

    Glasses with high conductivities can also be formed with the Lewis acids GeO 2 (11 ) and no doubt Bi 20 3, TeO2 , etc., but these have been less...P age 3 1. Mechanical Relaxation and Relation to Electrical Relaxation in Fast Ion-Conducting Glasses ...relaxation although considerable information was available for the classical alkali silicate and borate glasses . Our program was to utilize the rheovibron

  12. Preparation and Characterization of Conducting Polymer Latices by Chemical Polymerization of Aniline or Anisidine in Presence of Latex: Study of Their Electroactivity and Anti-Corrosion Properties

    Directory of Open Access Journals (Sweden)

    Bakhshali Massoumi

    2013-06-01

    Full Text Available Poly (vinylacetate-co-butylmethacrylate was prepared in presence of potassium persulphate as an oxidizing agent in aqueous solution of dodecylbenzene sulfonate sodium as an emulsifying agent. Then, aniline was polymerized by chemical oxidation method at three different concentrations of aniline monomer (0.1, 0.2 and 0.3 M in toluene in presence of poly(vinylacetate-co-butylmethacrylate in order to obtain polyaniline/poly(vinylacetate-co-butylmethacrylate. To prepare conducting-latex of polyanisidine/poly(vinylacetate-co-butylmethacrylate the same method was employed as above for aniline monomer in obtaining conducting polyaniline/poly(vinylacetate-co-butylmethacrylate latex. In addition, the purification of conducting-latex polymers, polyaniline/poly(vinylacetate-co-butylmethacrylate and polyanisidine/poly(vinylacetate-co-butylmethacrylate was conducted and preparation of tin layer films of conducting-latex polymers was carried out by casting method on glassy lames. The electroactivity properties of the prepared latex-polymers, polyaniline/poly(vinylacetate-co-butylmethacrylate and polyanisidine/poly(vinylacetate-co-butylmethacrylate were investigated by cyclic voltammetery (CV. The voltamogrames showed that the latex films were electroactive. Because of conductivity and electroactivity, the obtained films may find applications in anti-corrosion coatings. The anti-corrosion properties of conducting-latex polymers were studied on aluminum surface by impedance technique. The structure of the prepared conducting-latex polymers was confirmed by Fourier transform infrared (FTIR. Finally, the electrical conductivity of synthesized conducting-latex polymers, polyaniline/poly(vinylacetate-co-butylmethacrylate and polyanisidine/poly(vinylacetate-co-butylmethacrylate was measured by four probe technique.

  13. Specific features of the photoconductivity of semi-insulating cadmium telluride

    Energy Technology Data Exchange (ETDEWEB)

    Golubyatnikov, V. A.; Grigor’ev, F. I.; Lysenko, A. P., E-mail: aplysenko@hse.ru; Strogankova, N. I.; Shadov, M. B. [National Research University Higher School of Economics, Moscow Institute of Electronics and Mathematics (Russian Federation); Belov, A. G. [OAO GIREDMET State Research and Design Institute of the Rare-Metal Industry (Russian Federation)

    2014-12-15

    The effect of local illumination providing a high level of free-carrier injection on the conductivity of a sample of semi-insulating cadmium telluride and on the properties of ohmic contacts to the sample is studied. It is found that, irrespective of the illumination region, the contact resistance of ohmic contacts decreases and the concentration of majority carriers in the sample grows in proportion to the illumination intensity. It is shown that inherent heterogeneities in crystals of semi-insulating semiconductors can be studied by scanning with a light probe.

  14. Semi-mechanistic partial buffer approach to modeling pH, the buffer properties, and the distribution of ionic species in complex solutions.

    Science.gov (United States)

    Dougherty, Daniel P; Da Conceicao Neta, Edith Ramos; McFeeters, Roger F; Lubkin, Sharon R; Breidt, Frederick

    2006-08-09

    In many biological science and food processing applications, it is very important to control or modify pH. However, the complex, unknown composition of biological media and foods often limits the utility of purely theoretical approaches to modeling pH and calculating the distributions of ionizable species. This paper provides general formulas and efficient algorithms for predicting the pH, titration, ionic species concentrations, buffer capacity, and ionic strength of buffer solutions containing both defined and undefined components. A flexible, semi-mechanistic, partial buffering (SMPB) approach is presented that uses local polynomial regression to model the buffering influence of complex or undefined components in a solution, while identified components of known concentration are modeled using expressions based on extensions of the standard acid-base theory. The SMPB method is implemented in a freeware package, (pH)Tools, for use with Matlab. We validated the predictive accuracy of these methods by using strong acid titrations of cucumber slurries to predict the amount of a weak acid required to adjust pH to selected target values.

  15. Aluminum powder size and microstructure effects on properties of boron nitride reinforced aluminum matrix composites fabricated by semi-solid powder metallurgy

    International Nuclear Information System (INIS)

    Chen, Cunguang; Guo, Leichen; Luo, Ji; Hao, Junjie; Guo, Zhimeng; Volinsky, Alex A.

    2015-01-01

    Al matrix composite reinforced by hexagonal boron nitride (h-BN) with nearly full densification was successfully fabricated by the semi-solid powder metallurgy technique. The h-BN/Al composites were synthesized with elemental pure Al powder size of d_5_0=35, 12 and 2 μm. The powder morphology and the structural characteristics of the composites were analyzed using X-ray diffraction, scanning and transmission electron microscopy. The density, Brinell hardness and compressive behavior of the samples were characterized. Density measurement of the Al composites revealed that the composite densification can be effectively promoted by plenty of embedded liquid phase under pressure. Composites prepared using Al powder with varying granularity showed different grain characteristics, and in situ recrystallization occurred inside the original grains with 35 μm Al powder. A sharp interface consisting of Al/Al_2O_3/h-BN was present in the composites. Both the compressive strength and the fracture strain of the investigated composites increased with the decrease of the Al powder size, along with the Brinell hardness. The composite with 2 μm Al powder exhibited the highest relative density (99.3%), Brinell harness (HB 128), compressive strength (763 MPa) and fracture strain (0.299).

  16. Electrical properties (dielectric constant and conductivity) of igneous rock specimens; Kaseigan shiryo no hiyudenritsu, dodenritsu ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Toida, M; Miyajima, Y; Inaba, T [Kajima Corp., Tokyo (Japan)

    1997-10-22

    Dielectric constants and conductivity of several volcanic and plutonic rock specimens are measured and their dielectric characteristics and water contents are examined for the purpose of achieving a high-accuracy evaluation of the result of electromagnetic wave tomography conducted in situ. A total of 13 kinds of igneous rocks are examined, the volcanic rocks including andesite, basalt, and rhyolite and the plutonic rocks including granite and granodiorite. The specimens are caused to get wet and to be dried up, their resistance and static capacity are measured, and their dielectric constants and conductivity are determined. It is found that the dielectric constant increases upon addition of water and the rate of increase is greatly influenced by porosity, that conductivity increases upon addition of water and the rate of increase is much higher than that of the dielectric constant, and that the impact of added water on the electromagnetic wave propagation velocity and damping coefficient as calculated from actually measured dielectric constant and conductivity is greater on the damping coefficient than on the electromagnetic wave propagation velocity. 6 refs., 10 figs., 1 tab.

  17. On the conductive properties of MgO films grown on ultrathin hexagonal close-packed Co(0001) layer

    International Nuclear Information System (INIS)

    Gladczuk, L.; Aleszkiewicz, M.

    2013-01-01

    Here we present a scanning tunneling microscopy study of electrical conductivity of (110)-oriented MgO ultrathin films grown on hexagonal close-packed Co(0001) surface by molecular beam epitaxy, being a good candidate for tunneling barrier for future-generation spintronic devices. Three-dimensional growth of the tunneling barrier, expected for compressive strains emerging at the Co/MgO interface, is demonstrated by reflection high-energy electron diffraction and atomic force microscopy. The 5 eV height of the full barrier of MgO is reached at a layer thickness of 4 nm. Thinner MgO layers exhibit randomly distributed spots of the high conductance on the tunneling current map. The current–voltage curves indicate the existence of vacancies in MgO crystal lattice, lowering the resistivity of the tunneling barrier. - Highlights: • Conductivity of MgO barrier in MgO/hexagonal close-packed-Co bilayer • Conductivity strongly varies with MgO thickness • MgO barrier exhibits randomly distributed spots of particularly high conductance • Tunneling current–voltage curves indicate the existence of vacancies in MgO lattice

  18. In-plane conductance of thin films as a probe of surface chemical environment: Adsorbate effects on film electronic properties of indium tin oxide and gold

    Science.gov (United States)

    Swint, Amy Lynn

    Changes in the in-plane conductance of conductive thin films are observed as a result of chemical adsorption at the surface. Reaction of the indium tin oxide (ITO) surface with Bronsted acids (bases) leads to increases (decreases) in its in-plane conductance as measured by a four-point probe configuration. The conductance varies monotonically with pH suggesting that the degree of surface protonation or hydroxylation controls the surface charge density, which in turn affects the width of the n-type depletion layer, and ultimately the in-plane conductance. Measurements at constant pH with a series of tetraalkylammonium hydroxide species of varying cation size indicate that surface dipoles also affect ITO conductance by modulating the magnitude of the surface polarization. Modulating the double layer with varying aqueous salt solutions also affects ITO conductance, though not to the same degree as strong Bronsted acids and bases. Solvents of varying dielectric constant and proton donating ability (ethanol, dimethylformamide) decrease ITO conductance relative to H2O. In addition, changing solvent gives rise to thermally-derived conductance transients, which result from exothermic solvent mixing. The self-assembly of alkanethiols at the surface increases the conductance of ITO films, most likely through carrier population effects. In all cases examined the combined effects of surface charge, adsorbed dipole layer magnitude and carrier injection are responsible for altering the ITO conductance. Besides being directly applicable to the control of electronic properties, these results also point to the use of four-point probe resistance measurements in condensed phase sensing applications. Ultrasensitive conductance-based gas phase sensing of organothiol adsorption to gold nanowires is accomplished with a limit of detection in the 105 molecule range. Further refinement of the inherently low noise resistance measurement may lead to observation of single adsorption events at

  19. Improved transparent-conducting properties in N2- and H2- annealed GaZnO thin films grown on glass substrates

    International Nuclear Information System (INIS)

    Lee, Youngmin; Kim, Deukyoung; Lee, Sejoon

    2012-01-01

    The effects of N 2 - and H 2 - annealing on the transparent-conducting properties of Ga-doped ZnO (GaZnO) were examined. The as-grown GaZnO thin film, which was deposited on a soda-lime glass substrate by r.f. magnetron sputtering, exhibited moderate transparent-conducting properties: a resistivity of ∼10 0 Ω·cm and an optical transmittance of ∼86%. After annealing in N 2 or H 2 , the GaZnO samples showed great improvements in both the electrical and the optical properties. Particularly, in the H 2 -annealed sample, a dramatic decrease in the resistivity (7 x 10 -4 Ω·cm) with a considerable increase in the carrier concentration (4.22 x 10 21 cm -3 ) was observed. This is attributed to both an increase in the number of Ga-O bonds and a reduction in the number of chemisorbed oxygen atoms though H 2 annealing. The sample revealed an enhanced optical transmittance (∼91%), which comes from the Burstein-Moss effect. Namely, a blue-shift of the optical absorption edge, which results from the increased carrier concentration, was observed in the H 2 -annealed sample. The results suggest that hydrogen annealing can help improve the transparent conducting properties of GaZnO via a modification of the electrochemical bonding structures.

  20. Conduction properties of KcsA measured using brownian dynamics with flexible carbonyl groups in the selectivity filter.

    Science.gov (United States)

    Chung, Shin-Ho; Corry, Ben

    2007-07-01

    In the narrow segment of an ion conducting pathway, it is likely that a permeating ion influences the positions of the nearby atoms that carry partial or full electronic charges. Here we introduce a method of incorporating the motion of charged atoms lining the pore into Brownian dynamics simulations of ion conduction. The movements of the carbonyl groups in the selectivity filter of the KcsA channel are calculated explicitly, allowing their bond lengths, bond angles, and dihedral angels to change in response to the forces acting upon them. By systematically changing the coefficients of bond stretching and of angle bending, the carbon and oxygen atoms can be made to fluctuate from their fixed positions by varying mean distances. We show that incorporating carbonyl motion in this way does not alter the mechanism of ion conduction and only has a small influence on the computed current. The slope conductance of the channel increases by approximately 25% when the root mean-square fluctuations of the carbonyl groups are increased from 0.01 to 0.61 A. The energy profiles and the number of resident ions in the channel remain unchanged. The method we utilized here can be extended to allow the movement of glutamate or aspartate side chains lining the selectivity filters of other ionic channels.

  1. Ionic conductivity of metal oxides : an essential property for all-solid-state Lithium-ion batteries

    NARCIS (Netherlands)

    Chen, C.; Eichel, R.-A.; Notten, P.H.L.

    2017-01-01

    Essential progress has been made for adopting metal oxides (MeO) in various energy storage and energy conversion applications. Among these, utilizing MeO in Lithium-ions batteries (LIBs) seems to be one of the most promising applications. In particular, conductive Li-containing oxides or

  2. Ionic conductivity and fuel cell properties of apatite-type lanthanum silicates doped with Mg and containing excess oxide ions

    Energy Technology Data Exchange (ETDEWEB)

    Yoshioka, Hideki [Hyogo Prefectural Institute of Technology, 3-1-12 Yukihira-cho, Suma-ku, Kobe 654-0037 (Japan); Nojiri, Yoshihiro [Kyushu University, Department of Mechanical Engineering Science, Faculty of Engineering, Motooka 744, Nishi-ku, Fukuoka 819-0935 (Japan); Tanase, Shigeo [National Institute of Advanced Industrial Science and Technology, 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 (Japan)

    2008-11-30

    Enhancement of the ionic conductivity of lanthanum silicate-based apatites is examined with emphasis on optimizing the La composition and the Mg doping level at the same time. La{sub 10}Si{sub 5.8}Mg{sub 0.2}O{sub 26.8} and La{sub 9.8}Si{sub 5.7}Mg{sub 0.3}O{sub 26.4} show the highest level of the ionic conductivities among apatite silicates, 8.8 and 7.4 x 10{sup -} {sup 2} S cm{sup -} {sup 1} at 800 C, respectively, with a very low level of activation energy (0.42-0.43 eV). Their conductivities are higher than yttria stabilized zirconia (YSZ) below 900 C and even comparable to Sr and Mg doped lanthanum gallate (LSGM) below 550 C. A solid oxide fuel cell using La{sub 9.8}Si{sub 5.7}Mg{sub 0.3}O{sub 26.4} as an electrolyte with Ni-ceria cermet anode and Sr doped lanthanum cobaltite cathode exhibits a remarkable improvement in power generation compared to previous data using Pt electrodes. Structural investigation by the Rietveld analysis on the powder X-ray diffraction pattern shows significant enlargement of the bottleneck triangle sizes of the conduction channel with the Mg doping. (author)

  3. Heterogeneous in situ polymerization of polyaniline (PANI) nanofibers on cotton textiles: Improved electrical conductivity, electrical switching, and tuning properties.

    Science.gov (United States)

    Tissera, Nadeeka D; Wijesena, Ruchira N; Rathnayake, Samantha; de Silva, Rohini M; de Silva, K M Nalin

    2018-04-15

    Electrically conductive cotton fabric was fabricated by in situ one pot oxidative polymerization of aniline. Using a simple heterogeneous polymerization method, polyaniline (PANI) nano fibers with an average fiber diameter of 40-75 nm were grafted in situ onto cotton fabric. The electrical conductivity of the PANI nanofiber grafted fabric was improved 10 fold compared to fabric grafted with PANI nanoclusters having an average cluster size of 145-315 nm. The surface morphology of the cotton fibers was characterized using SEM and AFM. Electrical conductivity of PANI nanofibers on the cotton textile was further improved from 76 kΏ/cm to 1 kΏ/cm by increasing the HCl concentration from 1 M to 3 M in the polymerization medium. PANI grafted cotton fabrics were analyzed using FTIR, and the data showed the presence of polyaniline functional groups on the treated fabric. Further evidence was present for the chemical interaction of PANI with cellulose. Dopant level and morphology dependent electron transition behavior of PANI nanostructures grafted on cotton fabric was further characterized using UV-vis spectroscopy. The electrical conductivity of the PANI nano fiber grafted cotton fabric can be tuned by immersing the fabric in pH 2 and pH 6 solutions for multiple cycles. Copyright © 2018. Published by Elsevier Ltd.

  4. A study on the strength properties of the rock mass based on triaxial tests conducted at the Horonobe Underground Research Laboratory

    International Nuclear Information System (INIS)

    Aoyagi, Kazuhei; Ishii, Eiichi; Fujita, Tomoo; Kondo, Keiji; Tsusaka, Kimikazu

    2015-03-01

    Japan Atomic Energy Agency (JAEA) has been conducting R and D activities at the off-site URL at Horonobe, Hokkaido, Japan in order to enhance reliability of technology related to deep geological disposal of HLW in sedimentary rocks. In this report, strength properties (cohesion and frictional angle) of rock masses in the Koetoi and Wakkanai formations are investigated on the basis of triaxial tests conducted in the Horonobe URL considering the relative depths to the formation. Strength properties investigated in this report are compared with the properties obtained in the designing phase. The cohesion in the Koetoi Formation increased with increasing depth. On the other hand, in the transition zone of the Wakkanai Formation, the cohesion increased significantly in the shallow Wakkanai formation (transition zone). Below the transition zone, the cohesion does not significantly depend on the depth. Thus the strength properties between two formations were found to be different. Comparing the cohesions and frictional angles determined from triaxial tests with the values determined in the designing phase, there was no agreement between these values in almost all the depth. Thus it is essential to determine cohesion and frictional angle considering the relative depths to the formation for detailed understanding of strength properties of rock mass. A CD-ROM is attached as an appendix. (J.P.N.)

  5. First-principles simulations of the streching and final breaking of Al nanowires: Mechanical properties and electrical conductance

    Czech Academy of Sciences Publication Activity Database

    Jelínek, Pavel; Pérez, R.; Ortega, J.; Flores, F.

    2003-01-01

    Roč. 68, č. 8 (2003), 085403/1-085403/6 ISSN 0163-1829 Grant - others:European Project(XE) HPRN-CT-2000-00154; DGI-MCyT(ES) MAT2001-0665; Consejera de Educacio de la Comunidad de Madrid(ES) 07N/0050/2001 Institutional research plan: CEZ:AV0Z1010914 Keywords : nanowires * transport properties * first principles simulations Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.962, year: 2003

  6. Comment on: Shukla, M.K. et al., 2006: Physical and chemical properties of soils under some pinon-juniper-oak canopies in a semi-arid ecosystem in New Mexico

    DEFF Research Database (Denmark)

    Mollerup, Mikkel; Jensen, Jens Raunsø

    2008-01-01

    The paper by Shukla et al. [2006. Physical and chemical properties of soils under some pinon-juniper-oak canopies in an semi-arid ecosystem in New Mexico. Journal of Arid Environment 66, 673-685] treats interesting topics of sustainability of different ecosystems and their water availability....... However, the physical-based infiltration theories by Green and Ampt [1911. Studies on soil physics, I, flow of air and water through soils. Journal of Agricultural Science 4, 1-24] and Philip [1957. The theory of infiltration: 1. The infiltration equation and its solution. Soil Science 83, 345-357] seems...... to be applied without necessary reflections. The actual analysis can have resulted in coefficients without their original physical significance...

  7. Ash Deposit Formation and Deposit Properties. A Comprehensive Summary of Research Conducted at Sandia's Combustion Research Facility

    Energy Technology Data Exchange (ETDEWEB)

    Larry L. Baxter

    2000-08-01

    This report summarizes experimental and theoretical work performed at Sandia's Combustion Research Facility over the past eight years on the fate of inorganic material during coal combustion. This work has been done under four broad categories: coal characterization, fly ash formation, ash deposition, and deposit property development. The objective was to provide sufficient understanding of these four areas to be able to predict coal behavior in current and advanced conversion systems. This work has led to new characterization techniques for fuels that provide, for the first time, systematic and species specific information regarding the inorganic material. The transformations of inorganic material during combustion can be described in terms of the net effects of the transformations of these individual species. Deposit formation mechanisms provide a framework for predicting deposition rates for abroad range of particle sizes. Predictions based on these rates many times are quite accurate although there are important exceptions. A rigorous framework for evaluating deposit has been established. Substantial data have been obtained with which to exercise this framework, but this portion of the work is less mature than is any other. Accurate prediction of deposit properties as functions of fuel properties, boiler design, and boiler operating conditions represents the single most critical area where additional research is needed.

  8. Transient Heat Conduction

    DEFF Research Database (Denmark)

    Rode, Carsten

    1998-01-01

    Analytical theory of transient heat conduction.Fourier's law. General heat conducation equation. Thermal diffusivity. Biot and Fourier numbers. Lumped analysis and time constant. Semi-infinite body: fixed surface temperature, convective heat transfer at the surface, or constant surface heat flux...

  9. Conduction and TSC properties of LB films adsorbing cyanine dyes; Cyanine shikiso kyuchaku LB maku ni okeru denki dendo oyobi netsushigeki denryu tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Shinbo, K.; Kato, K.; Kaneko, F.; Kobayashi, S. [Niigata University, Niigata (Japan)

    1995-05-20

    The electric properties were investigated for phosphatidic acid (PA) LB films adsorbing cyanide dyes (NK-3) with sandwich electrodes. PA LB adsorbing the dyes and the monolayers of Cd salt without the dyes are deposited using subphases, containing various concentrations of the dyes and containing CdCl2 instead of the dyes, respectively. Conduction currents are measured at room temperature for the PA LB film devices. Increases in the conduction currents are observed in the LB films containing the dyes. Furthermore, the conduction currents remarkably increase using the Au upper electrode. The current(I) vs. voltage (V) properties nearly follow the Poole conduction, log(I)-V. Therefore, the conduction currents are very complicated and are thought to be due to composite mechanisms in the film and at the interface. TSC measurements are used to examine the dipolar polarizations in the PA LB films, in the temperature region between 150 K and 300 K. Remarkable increase of TSCs are observed above 260 K for the devices containing the dyes. The TSCs are caused by the dipolar polarizations, and increase with the quantity of the dyes contained in the LB devices and/or aggregations of the dyes. The results are useful for applications of ultrathin film devices in the future. 16 refs., 11 figs., 3 tabs.

  10. Effect of Zirconium Oxide Nanofiller and Dibutyl Phthalate Plasticizer on Ionic Conductivity and Optical Properties of Solid Polymer Electrolyte

    Science.gov (United States)

    Yasin, Siti Mariah Mohd; Ibrahim, Suriani

    2014-01-01

    New solid polymer electrolytes (SPE) based on poly(ethylene oxide) (PEO) doped with lithium trifluoromethanesulfonate (LiCF3SO3), dibutyl phthalate (DBP) plasticizer, and zirconium oxide (ZrO2) nanoparticles were prepared by solution-casting technique. The conductivity was enhanced by addition of dibutyl phthalate (DBP) plasticizer and ZrO2 nanofiller with maximum conductivity (1.38 × 10−4 Scm−1). The absorption edge and band gap values showed decreases upon addition of LiSO3CF3, DBP, and ZrO2 due to the formation of localized states in the SPE and the degree of disorder in the films increased. PMID:25133244

  11. Effect of Zirconium Oxide Nanofiller and Dibutyl Phthalate Plasticizer on Ionic Conductivity and Optical Properties of Solid Polymer Electrolyte

    Directory of Open Access Journals (Sweden)

    Siti Mariah Mohd Yasin

    2014-01-01

    Full Text Available New solid polymer electrolytes (SPE based on poly(ethylene oxide (PEO doped with lithium trifluoromethanesulfonate (LiCF3SO3, dibutyl phthalate (DBP plasticizer, and zirconium oxide (ZrO2 nanoparticles were prepared by solution-casting technique. The conductivity was enhanced by addition of dibutyl phthalate (DBP plasticizer and ZrO2 nanofiller with maximum conductivity (1.38×10-4 Scm-1. The absorption edge and band gap values showed decreases upon addition of LiSO3CF3, DBP, and ZrO2 due to the formation of localized states in the SPE and the degree of disorder in the films increased.

  12. Semi-leptonic interactions

    International Nuclear Information System (INIS)

    Gaillard, J.M.

    In spite of the presence of poorly understood strong interaction effects, the theory of hadronic currents leads to a considerable predictive power. This is shown in the discussion of the semi-leptonic decays

  13. Fabrication of conducting composite sheets using cost-effective graphite flakes and amorphous styrene acrylonitrile for enhanced thermistor, dielectric, and electromagnetic interference shielding properties

    Energy Technology Data Exchange (ETDEWEB)

    Panwar, Varij, E-mail: varijpanwarcertain@gmail.com [Electronics and Communication Engineering, Graphic Era University, Dehradun, Uttarakhand (India); Gill, Fateh Singh; Rathi, Vikas; Tewari, V.K. [Electronics and Communication Engineering, Graphic Era University, Dehradun, Uttarakhand (India); Mehra, R.M. [Sharda University, Greater Noida (India); Park, Jong-Oh, E-mail: jop@jnu.ac.kr [School of Mechanical Engineering, Chonnam National University, Gwangju (Korea, Republic of); Park, Sukho, E-mail: shpark12@dgist.ac.kr [Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology, Daegu (Korea, Republic of)

    2017-06-01

    The fabrication of strong conducting composite sheets (CCSs) using a simple technique with cost-effective materials is desirable for capacitor, decoupling capacitor, and electromagnetic interference (EMI) shielding applications. Here, we used cost-effective graphite flakes (GFs) as a conducting filler and amorphous poly (styrene-co-acrylonitrile) (PSAN) as an insulating polymer to fabricate a CCS via a simple mechanical mixing and hot compression molding process in 2.5 h, with the aim to save time and avoid the use of toxic reagents, which are generally used in chemical methods. In the present method, the GFs are connected in diffusively adhere polymer matrix, controlled by temperature and pressure that generate the conduction in the CCSs. The resulting PSAN/GF CCSs were characterized by using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and hardness tests. The GFs penetrated the interfacial region of PSAN, thus improving the thermistor and dielectric properties (dielectric constant, AC conductivity, and dissipation factor) of the PSAN/GF CCSs. Furthermore, the PSAN/GF CCSs showed enhanced hardness and EMI shielding effectiveness (SE) properties in the X-band frequency range (8.5–12.5 GHz). The percolation theory was implemented to DC and AC conductivity. To detect the transition of the dielectric properties, the dielectric constant of the CCSs was analyzed with increasing volume fraction of GFs in the radio frequency region. The improved dielectric constant, AC conductivity, and dissipation factor of the PSAN/GF CCS, indicated a significant improvement in their EMI shielding properties in the X-band frequency range, which were measured using the waveguide method. The ac conductivity of PSAN/GF CCS shows stable behavior in the higher frequency ranges. The EMISE of PSAN/GF CCS were found to increase with increasing GF content due to the absorbance mechanism. - Highlights: • Enhanced hardness and

  14. Thermal conductivity enhancements and viscosity properties of water based Nanofluid containing carbon nanotubes decorated with ag nanoparticles

    Science.gov (United States)

    Gu, Yanni; Xu, Sheng; Wu, Xiaoshan

    2018-01-01

    The water based nanofluid containing carbon nanotube (CNT) decorated with Ag nanoparticles (Ag/CNT) is prepared. Its thermal conductivity (k) enhancement increases with the thermal filler loading and the decoration quantity of Ag nanoparticles. The low absolute CNT content will decrease the tangles or aggregations among the CNTs, and it will be good at the Brownian motion of CNTs in the water. It has positive effects on the thermal conductivity of nanofluid. With the increase of Ag loading, the average size of Ag nanoparticles increased, and further results in the decrease of dispersing amount of Ag/CNT as the weight of Ag/CNT is fixed. Little dispersing quantity of Ag/CNT makes it possible that the Ag/CNT particles disperse well in the fluid. So it is not easy for CNTs to form aggregation. The high intrinsic k of CNT and the effective thermal conductive networks forming by CNTs and Ag nanoparticles are good at the k enhancement. With temperature increase the k of Ag/CNT nanofluid appears improvement. The study results make it possible to develop high-efficiency nanofluid for advanced thermal management regions.

  15. Structural and optical properties of sol-gel deposited proton conducting Ta{sub 2}O{sub 5} films

    Energy Technology Data Exchange (ETDEWEB)

    Ozer, N.; Lampert, C.M.

    1995-08-01

    Proton conducting tantalum oxide films were deposited by spin coating using a sol-gel process. The coating solutions were prepared using Ta(OC{sub 2}H{sub 5}){sub 5} as a precursor. X-ray diffraction studies determined that the sol-gel films, heat treated at temperatures below 400 C, were amorphous. Films heat treated at higher temperatures were crystalline Ta{sub 2}O{sub 5}. The solar transmission values (T{sub s}) of tantala films on glass generally range from 0.8--0.9 depending on thickness. The refractive index and the extinction coefficient were evaluated from transmittance characteristics in the UV-VIS-NIR regions. The refractive index values calculated at 550 nm increased from 1.78 to 1.97 with increasing heat treatment from 150 to 450 C. The films heat treated at different temperatures showed low absorption with extinction coefficients of less than k=1x10{sup -3} in the visible range. Spectrophotometric and impedance spectroscopic investigations performed on Ta{sub 2}O{sub 5} films revealed that these films have protonic conductivity of 3.2x10{sup -6} S/cm. The films are suitable for proton conducting layers in electrochromic (EC) devices.

  16. Thermal conductivity enhancements and viscosity properties of water based Nanofluid containing carbon nanotubes decorated with ag nanoparticles

    Science.gov (United States)

    Gu, Yanni; Xu, Sheng; Wu, Xiaoshan

    2018-06-01

    The water based nanofluid containing carbon nanotube (CNT) decorated with Ag nanoparticles (Ag/CNT) is prepared. Its thermal conductivity ( k) enhancement increases with the thermal filler loading and the decoration quantity of Ag nanoparticles. The low absolute CNT content will decrease the tangles or aggregations among the CNTs, and it will be good at the Brownian motion of CNTs in the water. It has positive effects on the thermal conductivity of nanofluid. With the increase of Ag loading, the average size of Ag nanoparticles increased, and further results in the decrease of dispersing amount of Ag/CNT as the weight of Ag/CNT is fixed. Little dispersing quantity of Ag/CNT makes it possible that the Ag/CNT particles disperse well in the fluid. So it is not easy for CNTs to form aggregation. The high intrinsic k of CNT and the effective thermal conductive networks forming by CNTs and Ag nanoparticles are good at the k enhancement. With temperature increase the k of Ag/CNT nanofluid appears improvement. The study results make it possible to develop high-efficiency nanofluid for advanced thermal management regions.

  17. Effect of doping concentration on the conductivity and optical properties of p-type ZnO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Pathak, Trilok Kumar [Semiconductor Research Lab, Department of Physics, Gurukula Kangri University, Haridwar (India); Kumar, Vinod, E-mail: vinod.phy@gmail.com [Department of Physics, University of the Free State, Bloemfontein (South Africa); Swart, H.C., E-mail: swarthc@ufs.ac.za [Department of Physics, University of the Free State, Bloemfontein (South Africa); Purohit, L.P., E-mail: proflppurohitphys@gmail.com [Semiconductor Research Lab, Department of Physics, Gurukula Kangri University, Haridwar (India)

    2016-01-01

    Nitrogen doped ZnO (NZO) thin films were synthesized on glass substrates by the sol–gel and spin coating method. Zinc acetate dihydrates and ammonium acetate were used as precursors for zinc and nitrogen, respectively. X-ray diffraction study showed that the thin films have a hexagonal wurtzite structure corresponding (002) peak for undoped and doped ZnO thin films. The transmittance of the films was above 80% and the band gap of the film varies from 3.21±0.03 eV for undoped and doped ZnO. The minimum resistivity of NZO thin films was obtained as 0.473 Ω cm for the 4 at% of nitrogen (N) doping with a mobility of 1.995 cm{sup 2}/V s. The NZO thin films showed p-type conductivity at 2 and 3 at% of N doping. The AC conductivity measurements that were carried out in the frequency range 10 kHz to 0.1 MHz showed localized conduction in the NZO thin films. These highly transparent ZnO films can be used as a possible window layer in solar cells.

  18. An electron conductive polymer, poly-aniline, in gas separation: optimisation of transport properties by alternated acid-base treatment

    International Nuclear Information System (INIS)

    Rebattet, Laurence

    1994-01-01

    The objective of this research thesis is to study the variation of gas permeation properties of poly-aniline during a doping/de-doping/re-doping cycle, and to study the evolution of the separation power of this polymer. Scanning electronic microscopy is used to study the microstructure and more particularly how the doping agent is distributed within the polymer. Permeabilities, diffusion coefficients, sorption solubilities and interaction energies are measured by using coupled permeation and micro-gravimetry-calorimetry methods. A range of gases (H 2 , O 2 , CO 2 , N 2 , CH 4 ) is analysed [fr

  19. A study on the optical, structural, electrical conductivity and dielectric properties of a lithium bismuth germanium tungsten glasses

    Energy Technology Data Exchange (ETDEWEB)

    Salem, Shaaban M., E-mail: shaabansalem@gmail.com [Department of Physics, Faculty of Science, Al Azhar University, Nasr City 11884, Cairo (Egypt); Abdel-Khalek, E.K. [Department of Physics, Faculty of Science, Al Azhar University, Nasr City 11884, Cairo (Egypt); Department of Physics, Faculty of Science, Jazan University (Saudi Arabia); Mohamed, E.A. [Department of Physics, Faculty of Science (Girl' s Branch), Al Azhar University, Nasr City, Cairo (Egypt); Department of Physics, Faculty of Science, Jazan University (Saudi Arabia); Farouk, M. [Department of Physics, Faculty of Science, Al Azhar University, Nasr City 11884, Cairo (Egypt); Department of Physics, Faculty of Science, Jazan University (Saudi Arabia)

    2012-02-05

    Highlights: Black-Right-Pointing-Pointer I report, for the first time, the effect of WO{sub 3} on Bi{sub 2}O{sub 3}, Li{sub 2}O, GeO{sub 2} and WO{sub 3} glasses through structural, optical, conductivity and dielectric studies. Black-Right-Pointing-Pointer Optical band gap E{sub op} for all types of electronic transitions, Urbach energy (E{sub r}), and refractive index determined. Black-Right-Pointing-Pointer The WO{sub 3} promotes as bitter constituent the reduction of W{sup 6+} to W{sup 5+} giving the bluish color. Black-Right-Pointing-Pointer Infrared spectra reveal characteristic GeO{sub 4}, GeO{sub 6}, Bi{sub 2}O{sub 3}, BiO{sub 6}, WO{sub 4} and WO{sub 6} units. Black-Right-Pointing-Pointer Based on ac and dc conductivity the conductivity increased and activation energies decreased with increase of WO{sub 3} content at all frequencies. - Abstract: Glasses in the system (65 - x)Bi{sub 2}O{sub 3}-15Li{sub 2}O-20GeO{sub 2}-xWO{sub 3} (where x = 2, 5 and 10 mol%) were prepared by normal melt quenching method. The change in density and molar volume in these glasses indicates the effect of WO{sub 3} on the glass structure. Fourier transform infrared (FT-IR) spectra show that these glasses are made up of GeO{sub 4}, GeO{sub 6}, BiO{sub 6}, BiO{sub 3}, WO{sub 4} and WO{sub 6} basic structural units. The structural units of BiO{sub 6}, GeO{sub 6} and WO{sub 6} increase with the increasing of WO{sub 3} content. The optical constants of these glasses are determined over a spectral range, providing the complex dielectric constant to be calculated. Higher values for the refractive index and dispersion are recorded due to the high polarizability of bismuth and tungsten ions. The values of the optical band gap E{sub g} for all types of electronic transitions and refractive index have been determined and discussed. The dc conductivity measured in the temperature range 423-623 K obeys Arrhenius law. The dielectric constant ({epsilon} Prime ), dielectric loss (tan {delta}) and

  20. Studies of YBa{sub 2}Cu{sub 3}O{sub 6+x} degradation and surface conductivity properties by Scanning Spreading Resistance Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Truchly, Martin, E-mail: martin.truchly@fmph.uniba.sk [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, 84248 Bratislava (Slovakia); Plecenik, Tomas; Krsko, Ondrej; Gregor, Maros; Satrapinskyy, Leonid; Roch, Tomas; Grancic, Branislav; Mikula, Marian [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, 84248 Bratislava (Slovakia); Dujavova, Agata; Chromik, Stefan [Institute of Electrical Engineering, Slovak Academy of Sciences, 84104 Bratislava (Slovakia); Kus, Peter; Plecenik, Andrej [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, 84248 Bratislava (Slovakia)

    2012-12-14

    Local surface conductivity properties and surface degradation of c-axis oriented YBa{sub 2}Cu{sub 3}O{sub 6+x} (YBCO) thin films were studied by Scanning Spreading Resistance Microscopy (SSRM). For the surface degradation studies, the YBCO surface was cleaned by ion beam etching and the SSRM surface conductivity map has been subsequently repeatedly measured over several hours in air and pure nitrogen. Average surface conductivity of the scanned area was gradually decreasing over time in both cases, faster in air. This was explained by oxygen out-diffusion in both cases and chemical reactions with water vapor in air. The obtained surface conductivity images also revealed its high inhomogenity on micrometer and nanometer scale with numerous regions of highly enhanced conductivity compared to the surroundings. Furthermore, it has been shown that the size of these conductive regions considerably depends on the applied voltage. We propose that such inhomogeneous surface conductivity is most likely caused by varying thickness of degraded YBCO surface layer as well as varying oxygen concentration (x parameter) within this layer, what was confirmed by scanning Auger electron microscopy (SAM). In our opinion the presented findings might be important for analysis of current-voltage and differential characteristics measured on classical planar junctions on YBCO as well as other perovskites.

  1. Semi-Autonomous Systems Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — VisionThe Semi-Autonomous Systems Lab focuses on developing a comprehensive framework for semi-autonomous coordination of networked robotic systems. Semi-autonomous...

  2. Density, excess properties, electrical conductivity and viscosity of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide + γ-butyrolactone binary mixtures

    International Nuclear Information System (INIS)

    Vraneš, Milan; Papović, Snežana; Tot, Aleksandar; Zec, Nebojša; Gadžurić, Slobodan

    2014-01-01

    Highlights: • Densities of [bmim][NTf 2 ] mixtures with γ-butyrolactone were measured. • Excess properties were calculated. • Nature of interactions between IL and GBL were discussed. • Specific conductivity and viscosity were also measured. • Walden plot is presented. - Abstract: Density, electrical conductivity and viscosity of binary liquid mixtures of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [bmim][NTf 2 ], with γ-butyrolactone (GBL) were measured at temperatures from (293.15 to 323.15) K and at atmospheric pressure over the whole composition range. Excess molar volumes have been calculated from the experimental densities and were fitted with Redlich–Kister polynomial equation. Other volumetric properties, such as isobaric thermal expansion coefficients, partial molar volumes, apparent molar volumes and partial molar volumes at infinite dilution have been also calculated, in order to obtain information about interactions between GBL and selected ionic liquid

  3. The effects of particle size and content on the thermal conductivity and mechanical properties of Al2O3/high density polyethylene (HDPE composites

    Directory of Open Access Journals (Sweden)

    2011-07-01

    Full Text Available The influences of filler size and content on the properties (thermal conductivity, impact strength and tensile strength of Al2O3/high density polyethylene (HDPE composites are studied. Thermal conductivity and tensile strength of the composites increase with the decrease of particle size. The dependence of impact strength on the particle size is more complicated. The SEM micrographs of the fracture surface show that Al2O3 with small particle size is generally more efficient for the enhancement of the impact strength, while the 100 nm particles prone to aggregation due to their high surface energy deteriorate the impact strength. Composite filled with Al2O3 of 0.5 µm at content of 25 vol% show the best synthetic properties. It is suggested that the addition of nano-Al2O3 to HDPE would lead to good performance once suitably dispersed.

  4. Effect of short-range ordering on the electrical conductivity and superconducting properties of Nb6C5 single crystals

    International Nuclear Information System (INIS)

    Utkina, T.G.

    1995-01-01

    Niobium carbide, NbC x , belongs to the family of so called interstital phases. Metal atoms form a face-centered cubic lattice, whose octahedral interstices are occupied by carbon atoms. The fraction (1 - x) of interstices remain vacant, and this determines the nonstoichiometry of these phases: most of them are characterized by a wide homogeneity range, 0.70 m ≅ 3308 - 3886 K). In contrast, the metalloid atoms exhibit high mobility at relatively low temperatures. For compositions close to Nb 6 C 5 (0.81 O-D ≅ 1300 K. The presence of vacancies in the carbon sublattice considerably affects the physical properties of carbides, which depend not only on total vacancy concentration but also on their distribution, i.e., on the degree of ordering (both short-range and long-range order) in the metalloid sublattice. The purpose of this work is to study the effects of such ordering on the superconducting properties of Nb 6 C 5 single crystals

  5. Numerical simulation of the induction heating of hybrid semi-finished materials into the semi-solid state

    Science.gov (United States)

    Seyboldt, Christoph; Liewald, Mathias

    2017-10-01

    Current research activities at the Institute for Metal Forming Technology (IFU) of the University of Stuttgart are focusing on the manufacturing of hybrid components using semi-solid forming strategies. As part of the research project "Hybrid interaction during and after thixoforging of multi-material systems", which is founded by the German Research Foundation (DFG), a thixoforging process for producing hybrid components with cohesive metal-to-metal connections is developed. In this context, this paper deals with the numerical simulation of the inductive heating process of hybrid semi-finished materials, consisting of two different aluminium alloys. By reason of the skin effect that leads to inhomogeneous temperature distributions during inductive heating processes, the aluminium alloy with the higher melting point is thereby assembled in the outer side and the alloy with the lower melting point is assembled in the core of the semi-finished material. In this way, the graded heat distribution can be adapted to the used materialś flow properties that are heavily heat dependent. Without this graded heat distribution a proper forming process in the semi-solid state will not be possible. For numerically modelling the inductive heating system of the institute, a coupling of the magnetostatic and the thermal solver was realized by using Ansys Workbench. While the electromagnetic field and its associated heat production rate were solved in a frequency domain, the temperature development was solved in the time based domain. The numerical analysis showed that because of the high thermal conductivity of the aluminium, which leads to a rapid temperature equalization in the semi-finished material, the heating process has to be fast and with a high frequency for produce most heat in the outer region of the material. Finally, the obtained numerical results were validated with experimental heating tests.

  6. Experimental and numerical analysis of semi-destructive device for in situ assessment of wood properties in compression parallel to grain

    Czech Academy of Sciences Publication Activity Database

    Kloiber, Michal; Kunecký, Jiří; Drdácký, Miloš; Tippner, J.; Sebera, V.

    2017-01-01

    Roč. 51, č. 2 (2017), s. 345-356 ISSN 0043-7719 R&D Projects: GA MK(CZ) DG16P02M026; GA MŠk(CZ) LO1219 Keywords : finite element method * experimental and numerical analysis * historical construction * mechanical properties of wood Subject RIV: AL - Art, Architecture, Cultural Heritage OBOR OECD: Paper and wood Impact factor: 1.509, year: 2016 http://link.springer.com/article/10.1007%2Fs00226-016-0881-6

  7. Electronic structures, elastic properties, and minimum thermal conductivities of cermet M{sub 3}AlN

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jin [Faculty of Materials and Energy, Southwest University, Chongqing 400715 (China); Key Laboratory of Liquid–Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Chen, ZhiQian, E-mail: chen_zq@swu.edu.cn [Faculty of Materials and Energy, Southwest University, Chongqing 400715 (China); Li, ChunMei; Li, Feng; Nie, ChaoYin [Faculty of Materials and Energy, Southwest University, Chongqing 400715 (China)

    2014-08-15

    The electronic structures and elastic anisotropies of cubic Ti{sub 3}AlN, Zr{sub 3}AlN, and Hf{sub 3}AlN are investigated by pseudopotential plane-wave method based on density functional theory. At the Fermi level, the electronic structures of these compounds are successive with no energy gap between conduct and valence bands, and exhibit metallicity in ground states. In valence band of each partial density of states, the different orbital electrons indicate interaction of corresponding atoms. In addition, the anisotropy of Hf{sub 3}AlN is found to be significantly different from that of Ti{sub 3}AlN and Zr{sub 3}AlN, which involve the differences in the bonding strength. It is notable that Hf{sub 3}AlN is a desired thermal barrier material with the lowest thermal conductivity at high temperature among the three compounds. - Graphical abstract: 1.Young's moduli of anti-perovskite Ti{sub 3}AlN, Zr{sub 3}AlN, and Hf{sub 3}AlN in full space. 2.Electron density differences on crystal planes (1 0 0), (2 0 0), and (1 1 0) of anti-perovskite Zr{sub 3}AlN. - Highlights: • We calculated three anti-perovskite cermets with first-principles theory. • We illustrated 3D Young modulus and found the anomalous anisotropy. • We explained the anomaly and calculated the minimum thermal conductivities.

  8. Method of making composition suitable for use as inert electrode having good electrical conductivity and mechanical properties

    Science.gov (United States)

    Ray, S.P.; Rapp, R.A.

    1986-04-22

    An improved inert electrode composition is suitable for use as an inert electrode in the production of metals such as aluminum by the electrolytic reduction of metal oxide or metal salt dissolved in a molten salt bath. The composition comprises one or more metals or metal alloys and metal compounds which may include oxides of the metals comprising the alloy. The alloy and metal compounds are interwoven in a network which provides improved electrical conductivity and mechanical strength while preserving the level of chemical inertness necessary for such an electrode to function satisfactorily. 8 figs.

  9. Changes in Myocardial Composition and Conduction Properties in Rat Heart Failure Model Induced by Chronic Volume Overload

    Czech Academy of Sciences Publication Activity Database

    Sedmera, David; Neckář, Jan; Beneš Jr., Jiří; Pospíšilová, J.; Petrák, J.; Sedláček, K.; Melenovský, V.

    2016-01-01

    Roč. 7, Aug 25 (2016), s. 367 ISSN 1664-042X R&D Projects: GA MŠk(CZ) ED1.1.00/02.0109; GA ČR(CZ) GAP302/11/1308; GA ČR(CZ) GA13-12412S; GA MZd(CZ) NV15-27735A Institutional support: RVO:67985823 Keywords : connexin43 * autonomic heart innervation * hypertrophy * conduction velocity * aorto-caval fistula Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery Impact factor: 4.134, year: 2016

  10. Volumetric, viscosity, and electrical conductivity properties of aqueous solutions of two n-butylammonium-based protic ionic liquids at several temperatures

    International Nuclear Information System (INIS)

    Xu, Yingjie

    2013-01-01

    Highlights: • Densities and viscosities of N4AC + water and N4NO 3 + water mixtures were measured. • Volumetric and viscosity properties were calculated. • Redlich–Kister equation was used to correlate the excess molar volumes and viscosity deviations. • Electrical conductivity was fitted according to the empirical Casteel–Amis equation. • The interactions and structural effects of N4AC or N4NO 3 with water were analyzed. -- Abstract: Densities and viscosities of (n-butylammonium acetate (N4AC) protic ionic liquid + water) and (n-butylammonium nitrate (N4NO 3 ) protic ionic liquid + water) mixtures were measured at T = (293.15, 298.15, 303.15, 308.15, and 313.15) K under atmospheric pressure. Electrical conductivities of the above-mentioned systems were determined at 298.15 K. Excess molar volumes and viscosity deviations were obtained from the experimental results and fitted to the Redlich–Kister equation with satisfactory results. Other volumetric properties, such as apparent molar volumes, partial molar volumes, and excess partial molar volumes were also calculated. The concentration dependence of electrical conductivity was fitted according to the empirical Casteel–Amis equation. Based on the measured and derived properties, the molecular interactions and structural factors in the above-mentioned systems were discussed

  11. Effects of (La, Sr) co-doping on electrical conduction and magnetic properties of BiFeO3 nanoparticles

    International Nuclear Information System (INIS)

    Liu Li; Wang Shouyu; Yin Zi; Zhang Chuang; Li Xiu; Yang Jiabin; Liu Weifang; Xu Xunling

    2016-01-01

    Multiferroic material as a photovoltaic material has gained considerable attention in recent years. Nanoparticles (NPs) La 0.1 Bi 0.9−x Sr x FeO y (LBSF, x = 0, 0.2, 0.4) with dopant Sr 2+ ions were synthesized by the sol–gel method. A systematic change in the crystal structure from rhombohedral to tetragonal upon increasing Sr doping was observed. There is an obvious change in the particle size from 180 nm to 50 nm with increasing Sr substitution into LBFO. It was found that Sr doping effectively narrows the band gap from ∼ 2.08 eV to ∼ 1.94 eV, while it leads to an apparent enhancement in the electrical conductivity of LBSF NPs, making a transition from insulator to semiconductor. This suggests an effective way to modulate the conductivity of BiFeO 3 -based multiferroic materials with pure phase by co-doping with La and Sr at the A sites of BiFeO 3 . (paper)

  12. Effect of double bonds on the conducting properties of ciguatoxin 3C and tetrahydropyrane-based polymers: a theoretical study.

    Science.gov (United States)

    Matus, Myrna H; Garza, Jorge; Galván, Marcelo

    2006-01-26

    The electronic structure of the ciguatoxin 3C is analyzed through the Kohn-Sham model by using two different kinds of basis sets: localized basis set (Gaussian functions) and nonlocalized basis set (plane wave functions). With the localized basis functions, two approximations are used for the exchange-correlation functional: the local density approximation and the generalized gradient approximation. With the nonlocalized basis set, just the local density approximation is used. The energy gap, obtained from the frontier molecular orbitals, for this molecule predicts that this system is a semiconductor, even when the number of double bonds is increased inside the structure. However, as large molecules built with the basic unit--the tetrahydropyrane--of the ciguatoxin 3C are found in nature, it suggests studying the gap in polymeric systems built with the basic unit of this molecule. It is demonstrated that the presence of double bonds reduces considerably the gap, indicating the possibility of forming conducting materials by introducing double bonds in this kind of molecular systems. Thus, molecules strongly linked with biological systems can be used as precursor to build electric conducting systems.

  13. Effects of transverse electric field and heterogeneity of a poorly electrically conducting fluid saturated nanoporous zeolites acquiring smart material properties

    International Nuclear Information System (INIS)

    Rudraiah, N.; Ranganna, G.; Shilpa, P.

    2013-01-01

    In this paper we explain a Mathematical Model involving Darcy linear drag, Forchheimer quadratic drag, horizontal density gradient and the variation of electrical conductivity due to organic substances dissolved in a heterogeneous Boussinesq poorly conducting couple stress fluid flow (PCPCSFF) through Nano Porous Zeolites regarded as densely packed porous media. Initially, the flow is at rest and set in motion due to initial piecewise horizontal concentration gradient. Analytical solutions, for electric potential using the Maxwell field equations and for velocity and density using nonlinear Darcy – Forchheimer equation in the presence of couple stress and electric force are obtained using the method of time series evolution. The analytical solutions for streamlines and density are computed for different values of time, t, for a particular value of electric number W 1 and couple stress parameter β and the results are depicted graphically in figures 1 and 2. From these figures we found that the streamlines are closer in the region of x 0 and the density profiles are concentrated in the lower region and develop curvature in the presence of electric field and couple stress parameter. The physical reason for the nature of streamlines and density profiles are given in the last section and some important conclusions are drawn. (author)

  14. Effects of in situ plasma treatment on optical and electrical properties of index-matched transparent conducting oxide layer

    International Nuclear Information System (INIS)

    Lim, Yong Hwan; Yoo, Hana; Choi, Bum Ho; Kim, Young Baek; Lee, Jong Ho; Shin, Dong Chan

    2010-01-01

    We investigated the effects of in situ plasma-treatment on optical and electrical properties of index-matched indium tin oxide (IMITO) thin film. To render the IMITO-coated surface hydrophilic and study the optical and electrical characteristics, we performed in situ oxygen plasma post-treatment without breaking vacuum. The 94.6% transmittance in the visible wavelength range (400-700 nm) increased on average to 96.4% and the maximum transmittance reached 98% over a broad wavelength range. The surface roughness and sheet resistance improved from 0.9 nm and 200 Ω/sq to 0.0905 nm and 100 Ω/sq, respectively, by in situ plasma post-treatment. We confirmed by contact angle measurement that the hydrophobic IMITO surface was altered to hydrophilic. The improved optical and electrical characteristics of in situ plasma-treated IMITO makes it adequate for high-resolution liquid crystal on silicon displays.

  15. Effect of thermal annealing on the properties of transparent conductive In–Ga–Zn oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ling [Key Laboratory of Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi' an 710049, China and School of Information Science and Engineering, Shandong University, Jinan 250100 (China); Fan, Lina; Li, Yanhuai; Song, Zhongxiao; Ma, Fei, E-mail: mafei@mail.xjtu.edu.cn, E-mail: chlliu@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Liu, Chunliang, E-mail: mafei@mail.xjtu.edu.cn, E-mail: chlliu@mail.xjtu.edu.cn [Key Laboratory of Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi' an 710049 (China)

    2014-03-15

    Amorphous In–Ga–Zn oxide (IGZO) thin films were prepared using radio frequency magnetron sputtering at room temperature. Upon thermal annealing at temperatures even up to 500 °C, the amorphous characteristics were still maintained, but the electronic properties could be considerably enhanced. This could be ascribed to the increased optical band gap and the increased oxygen vacancies, as corroborated by the microstructure characterizations. In addition, the surface became smoother upon thermal annealing, guaranteeing good interface contact between electrode and a-IGZO. The optical transmittance at 400–800 nm exceeded 90% for all samples. All in all, thermal annealing at appropriate temperatures is expected to improve the performances of relevant a-IGZO thin film transistors.

  16. Hidrogéis semi-IPN baseados em rede de alginato-Ca2+ com PNIPAAm entrelaçado: propriedades hidrofílicas, morfológicas e mecânicas Semi-IPN hydrogels based on alginate-Ca2+ network and PNIPAAm: hydrophilic, morphological and mechanical properties

    Directory of Open Access Journals (Sweden)

    Márcia R. de Moura

    2008-06-01

    Full Text Available Neste trabalho, a termossensibilidade dos hidrogéis do tipo semi-IPN baseados em rede de alginato-Ca2+com poli(N-isopropil acrilamida (PNIPAAm entrelaçado, com diferentes teores de alginato e de PNIPAAm, foi caracterizada por meio de medidas de grau de intumescimento (Q, microscopia eletrônica de varredura (MEV e propriedades mecânicas [tensão máxima de compressão (σ, densidade aparente de reticulação (νe e módulo de elasticidade (E]. Os valores de Q variam inversamente com νe. Para o parâmetro νe contribuem as concentrações de retículos alginato-Ca2+ e de cadeias de PNIPAAm. Hidrogéis com maiores valores de Q possuem maiores poros. Resultados de propriedades mecânicas demonstraram que hidrogéis com maior νe apresentam maior rigidez e resistência à compressão, sendo este efeito mais intenso acima da LCST do PNIPAAm. O controle dessas propriedades nesses hidrogéis termos-sensíveis torna esses materiais potencialmente viáveis para aplicação em sistemas carreadores para liberação controlada e/ou prolongada de fármacos e substratos para crescimento e cultura de célula.In this study, the thermosensitivity of semi-IPN hydrogels based on alginate-Ca2+ network and having PNIPAAm entangled was characterized by swelling degree (Q, scanning electron microscopy (SEM and mechanical properties [compressive stress (σ, apparent cross-linking density (νe and modulus of elasticity (E]. The Q values change inversely to the νe ones. The concentrations of the alginate-Ca2+ cross-linking and of the PNIPAAm chains contribute to the νe parameter. Higher values of Q correlate to larger pores size in the hydrogel. Hydrogels richer in alginate and PNIPAAm were more rigid, highly resistant to deformation because of their higher compressive modulus of elasticity. This is more intense at temperatures above the LCST of PNIPAAm in water (32-35 °C. The control of thermosensitive properties by tailoring the alginate-Ca2+/PNIPAAm ratio and

  17. Synthesis and thermal properties of the MA/HDPE composites with nano-additives as form-stable PCM with improved thermal conductivity

    International Nuclear Information System (INIS)

    Tang, Yaojie; Su, Di; Huang, Xiang; Alva, Guruprasad; Liu, Lingkun; Fang, Guiyin

    2016-01-01

    Highlights: • MA/HDPE composites with nano-additives were prepared for thermal conductivity enhancement. • Microstructure and chemical structure of the FSPCM were analyzed. • Thermal properties and thermal reliability of the FSPCM were investigated. • Thermal conductivity of the FSPCM can be enhanced by adding NAO and NG. - Abstract: For the purpose of improving the thermal conductivity of the form–stable phase change materials (FSPCM), two types of nano–powders with high thermal conductivity were added into the samples. In the modified FSPCM, myristic acid (MA) was used as a solid–liquid phase change material (PCM), high density polyethylene (HDPE) acted as supporting material to prevent the leakage of the melted MA. Nano–Al 2 O 3 (NAO) and nano–graphite (NG) were the additives for thermal conductivity enhancement. Scanning electronic microscope (SEM), Fourier transformation infrared spectroscope (FT–IR) and X-ray diffractometer (XRD) were used to analyze the microstructure, chemical structure and crystalline phase of the samples, respectively. Furthermore, the specific latent heat and phase transition temperature, thermal conductivity and thermal reliability were investigated using differential scanning calorimeter (DSC), thermal conductivity meter and thermo–gravimetric analyzer (TGA). The results showed that the MA was uniformly absorbed in the HDPE matrices and there was no leakage during the melting process when the mass fraction of the MA in the MA/HDPE composite was less than 70%. The DSC results revealed that the modified FSPCM have a constant phase change temperature and high specific latent heat. The thermal conductivity of the FSPCM was measured in the solid (30 °C) and liquid (60 °C) states of the MA. When the mass fraction of nano–powder additives is 12%, the thermal conductivities of the FSPCM increase by 95% (NAO) and 121% (NG) at 30 °C. It is anticipated that the FSPCM possess a potential application for thermal energy

  18. The ionic conductivity and dielectric properties of Ba{sub 1−x}Sn{sub x}F{sub 2} solid solutions prepared by mechanochemical milling

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Mohamad M., E-mail: mmohamad@kfu.edu.sa [Department of Physics, College of Science, King Faisal University, Al-Ahsaa 31982 (Saudi Arabia); Department of Science and Mathematics, Faculty of Education in The New Valley, Assiut University, El-Kharga 72511 (Egypt); Yamane, Yohei; Yamada, Koji [Department of Applied Molecular Chemistry, College of Industrial Technology, Nihon University, Narashino, Chiba 275-8575 (Japan)

    2013-09-01

    Highlights: • New Ba{sub 1−x}Sn{sub x}F{sub 2} compositions have been synthesized by the mechanochemical milling. • Considerably higher ionic conductivity is obtained when increasing SnF{sub 2} content. • The increased conductivity is due to the enhanced mobility of fluoride ions -- Abstract: Solid solutions of Ba{sub 1−x}Sn{sub x}F{sub 2} fluoride ion conductors, with x = 0.1–0.4, have been synthesized by the mechanochemical milling technique for the first time. All of the prepared materials crystallize in the cubic fluorite-type structure, which indicates that the solid solution can be synthesized in the studied composition range by the mechanochemical milling technique at ambient temperature and pressure. The ionic conduction of the investigated materials has been studied by impedance spectroscopy. The ionic conductivity increased considerably, by up to six orders of magnitude compared to pure un-milled BaF{sub 2}, with increasing SnF{sub 2} content. From the analysis of the conductivity spectra of the investigated materials it is found that the concentration of mobile fluoride ions is independent of temperature with almost the same values for the investigated materials. The present results suggest that the enhanced mobility of mobile ions is the origin of the higher ionic conductivity. The dielectric properties and the associated relaxation phenomena of the current materials are also described.

  19. Effect of plasticization on the conductivity and dielectric properties of starch-chitosan blend biopolymer electrolytes infused with NH4Br

    Science.gov (United States)

    Shukur, M. F.; Majid, N. A.; Ithnin, R.; Kadir, M. F. Z.

    2013-11-01

    The present work examines the effect of plasticization on the conductivity and dielectric properties of starch-chitosan blend biopolymer electrolytes. Initial Fourier transform infrared (FTIR) spectroscopy analysis of the hydroxyl band recorded 3280 cm-1 for starch and 3354 cm-1 for chitosan. The FTIR spectrum of starch-chitosan blend films shows that the hydroxyl band shifted to 3288 cm-1, indicating interaction between pure starch and chitosan. Different concentrations of ammonium bromide (NH4Br) were then added to the blend solution and stirred until complete dissolution. The homogeneous solutions were then placed onto different plastic Petri dishes, where they were left to dry. The highest conductivity value of (9.72 ± 0.95) × 10-5 S cm-1 was obtained with addition of 35 wt% NH4Br. Addition of 30 wt% ethylene carbonate increased the conductivity value to (1.44 ± 0.51) × 10-3 S cm-1. The plots of dielectric constant, ɛr, against frequency for both plasticized and unplasticized systems show non-Debye behaviour. The temperature dependence of the power law exponent for the highest conducting sample in the unplasticized system follows the small polaron hopping model while the conduction mechanism of the highest conducting sample in the plasticized system can be represented by the quantum mechanical tunnelling model.

  20. Effects of reduction temperature on the optoelectronic properties of diodes based on n-type Si and reduced graphene oxide doped with a conductive polymer

    International Nuclear Information System (INIS)

    Zeng, Jian-Jhou; Lin, Yow-Jon; Ruan, Cheng-He; Lin, Jian-Huang

    2013-01-01

    The effect of reduction temperature on the optoelectronic properties of diodes based on n-type Si and reduced graphene oxide (RGO) doped with a conductive polymer [poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) (PEDOT:PSS)] was examined in this study. It is found that conductivity of RGO-doped PEDOT:PSS films increases with increasing reduction temperature of graphene oxide (GO) sheets. The improvement of electrical conductivity is considered to mainly come from the carrier mobility enhancement. In addition, the ideality factor of n-type Si/RGO-doped PEDOT:PSS diodes decreases with increasing reduction temperature of GO sheets. The device-performance improvement originates from high-mobility hole transport combined with long-lifetime electron trapping in the RGO-doped PEDOT:PSS film. In addition, note that a suitable reduction temperature is an important issue for improving the device performance. (paper)